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Morphological, rheological and electrochemical studies ofpoly(ethylene oxide) electrolytes containing fumed silicananoparticles  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the rheology and crystallization of composite Poly(Ethylene Oxide) (PEO) electrolytes were studied by dynamic mechanical analysis, DSC and polarized light microscopy. The effects of fumed silica nanoparticles on the conductivities of the polymer electrolytes at temperatures above and below their melting point were measured and related to their rheology and crystallization behavior, respectively. The electrolyte/electrode interfacial properties and cycling performances of the composite polymer electrolytes in Li/Li cells are also discussed. The measured electrochemical properties were found to depend heavily on the operational environments and sample processing history.

Xie, Jiangbing; Kerr, John B.; Duan, Robert G.; Han, Yongbong

2003-06-01

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THE EFFECT OF ELECTROLYTE CONCENTRATION AND PH ON THE FLOCCULATION AND RHEOLOGICAL BEHAVIOUR OF KAOLINITE SUSPENSIONS  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of the electrolyte concentration and pH on the settling behaviour, floc sizes and rheological behaviour of kaolinite suspensions were investigated. The results show that the settling behaviour of kaolinite changes with the ionic strength and pH of the suspension. In the acidic pH range, (pH 2 particles settle in flocculated form regardless of electrolyte concentration, however, in the basic pH range, the particles settle both, in dispersed form (at lower electrolyte concentrations and in flocculated form (at higher electrolyte concentrations. The Bingham yield stress and time-dependent behaviour for these flocculated and deflocculated suspensions was investigated. In this study, the fundamental of structural kinetic model (SKM was used to investigate the time-dependent viscosity behaviour of flocculated and deflocculated kaolinite suspensions. It was found that the kaolinite suspensions in the deflocculated form show viscosity time-independent behaviour with negligible Bingham yield stress. While, the flocculated suspensions show marked non-Newtonian time-dependent behaviour. This work has been very successful in establishing the link among particle-particle interactions, floc size, Bingham yield stress, breakdown rate constant, and extent of thixotropy.

M. S. NASSER

2009-12-01

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The rheology of oxide dispersions and the role of concentrated electrolyte solutions  

International Nuclear Information System (INIS)

Stability control of particulate dispersions is critical to a wide range of industrial processes. In the UK nuclear industry, significant volumes of waste materials arising from the corrosion products of Magnox fuel rods currently require treatment and storage. The majority of this waste is present as aqueous dispersions of oxide particulates. Treatment of these dispersions will require a variety of unit operations including mobilisation, transport and solid- liquid separation. Typically these processes must operate across a narrow optimal range of pH and the dispersions are, almost without exception, found in complex electrolyte conditions of high overall concentration. Knowledge of the behaviour of oxides in various electrolyte conditions and over a large pH range is essential for the efficient design and control of any waste processing approach. The transport properties of particle dispersions are characterised by the rheological properties. It is well known that particle dispersion rheology is strongly influenced by particle-particle interaction forces, and that particle-particle interactions are strongly influenced by adsorbed ions on the particle surfaces. Here we correlate measurements of the shear yield stress and the particle zeta potentials to provide insight as to the role of ions in moderating particle interactions. The zeta potential of model TiO2 suspensions were determined (Colloidal Dynamics Zeta Probe) over a range of pH for a series of alkbe) over a range of pH for a series of alkali metal halides and quaternary ammonium halides at a range of solution concentrations (0.001 M - 1 M). The results show some surprising co-ion effects at high electrolyte concentrations (>0.5 M) and indicate that even ions generally considered to be indifferent induce a shift in iso-electric point (i.e.p.) which is inferred as being due to specific adsorption of ions. The shear yield stress values of concentrated titania dispersions were measured using a Bohlin C-VOR stress controlled rheometer. The shear yield stress of a material is defined as the minimum applied shear stress required to induce flow. The yield stress vs. pH curves obtained reflected the shifts in i.e.p. seen in the zeta potential results. Interestingly, specific ion adsorption results in an unexplained increase in the value of the yield stress over that expected for simple systems with no such interfacial ion adsorption. Possible reasons for this effect such as ion-ion correlation effects are discussed. The importance of this increased attraction for the mobilisation of settled solids in an aqueous environment and especially the likely effects on the treatment of Magnox fuel waste materials is discussed. (authors)

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Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells  

Directory of Open Access Journals (Sweden)

Full Text Available Developed in the early 1900's, the “Haber-Bosch” synthesis is the dominant NH3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS, more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13×10?8 mol s?1 cm?2, obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe0.7Cu0.1Ni0.2O3, cathode. At high temperatures (>500oC the maximum rate was 9.5*10-9 mol s?1 cm?2 using Ce0.8Y0.2O2-? -[Ca3(PO42 -K3PO4] as electrolyte and Ag-Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level, are discussed.

MichaelStoukides

2014-01-01

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Rheology of concentrated, heterogeneous slurries containing >1M electrolyte - a case study in nuclear waste suspensions  

International Nuclear Information System (INIS)

Neutralized current acid waste (NCAW) simulant was produced to chemically simulate the properties of the washed solids of a high-level waste stream generated from the reprocessing of irradiated nuclear fuel. The NCAW simulant was evaluated by viscosity, yield stress, solid loading, particle size, and anion and cation solubility. For similar solid loadings and pH, the NCAW simulant had higher yield stresses and viscosities than NCAW. The differences in the rheological behavior between NCAW and the simulant were attributed to differences in the suspension microstructure. The effects of formic and nitric acid additions to the NCAW simulant on yield stress and viscosity were measured as a function of solids loading and pH for both acids. In addition, anion and cation solubilities were evaluated. Viscosity and yield stress decreased as pH was lowered. The change in rheological properties was attributed to floc breakdown and particle dissolution, which were initiated by the solubilization of the waste constituents. These results show that the effectiveness of the simulant studied here is unproven rheologically. (orig.)

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Synthesis and electric conductivity of solid electrolyte of NASICON type  

International Nuclear Information System (INIS)

The sequences of solid-phase reactions during synthesis of solid electrolyte corresponding to Na3Zr2Si2PO12 stoichiometric composition are studied. It is shown that solid-phase reaction of ZrO(NO3)2x2H2O, Na2CO3, NH4H2PO4 and amorphous SiO2 proceeds through stages of nitrate-zirconium oxide dehydration, ammonium dihydrophosphate decomposition, formation and decomposition of ammonium and sodium. Intermediate reaction products are sodium and zirconium phosphates, and some of ZrO2 takes part in the reaction in the form of amorphous or metastable tetragonal modification and another part transforms into a stable monoclinic one. NASICON formation starts at 1000 deg C, only at this stage silicon dioxide begins to react, which is already transformed from amorphous phase into a mixture of tridymite and ?-crystobalyte. After annealing at 1230 deg C a single-phase solid electrolyte Na3Zr2Si2PO12 having conductivity 0.14 S/cm at 300 deg C and 0.00028 S/cm at 25 deg C

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Synthesis and rheological properties of poly(vinyl alcohol)  

International Nuclear Information System (INIS)

Vinyl acetate usually used in PVA resin preparation was converted to PVAc by bulk poly-merization using AIBN as a initiator and PVA was synthesized by changing the concentration of NaOH added for saponification subsequently. As a result of estimating molecular weight using GPC, molecular weight increased as the NaOH concentration increased to 2.5 N, 5.0 N, 7.5 N and 10.0 N and polydispersity had similar values of 2.1?2.3, however, showed slightly decreasing tendency. In addition, PVA saponificated by 10.0 N-NaOH showed high syndiotacticity in observation of tacticity using NMR spectroscopy. From this fact, the degree of tacticity was predicted to be high and it was in good agreement with the tendency of polydisperisity by GPC. Also, from the result of FT-IR spectroscopy, it might be known that hydrolysis was more promoted in the PVA with 10.0 N-NaOH than other NaOH concentration. Intrinsic viscosity measured using Ubbelohde viscometer, which increased as the concentration of NaOH added for saponification increased. The change of shear strength with the change of shear rate was investigated using Brookfield viscometer, in consequence, viscosity of PVA synthesized decreased as shear rate increased. PVA solution confirmed to show the shear thinning behavior by Casson plot and PVA with 10.0 N-NaOH had the largest yield value. DSC measurement was performed to know the thermal properties of PVA. Tp had nearly constant value of 214 .deg. C in all cases except for adding 2.deg. C in all cases except for adding 2.5 N-NaOH and ?H was increased as the concentration of NaOH increased. From this properties, it was concluded that the degree of hydrogen bonding was proportional to the added concentration of NaOH and the increase of the degree of hydrogen bonding and hydrophobic interaction could affect the rheological and thermal properties of title compound

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Preparation and electrochemical properties of LiMn2O4 by a rheological-phase-assisted microwave synthesis method  

International Nuclear Information System (INIS)

By using LiCO3 and MnO2, a rheological-phase-assisted microwave synthesis method has been applied in the fast preparation of spinel LiMn2O4 in order to reduce the cost of cathode materials. Comparing with the pristine LiMn2O4 obtained by the traditional solid-state reaction method, the structure and surface morphology of the samples synthesized by the rheological-phase-assisted microwave synthesis method have been investigated. The powders were used as positive materials for lithium-ion battery, whose charge/discharge properties and cycle performance have been examined in detail. As a result, the powders prepared by the rheological phase-assisted microwave synthesis method at 750 deg C are pure spinel LiMn2O4 with regular shapes and uniform distribution, which exhibit higher capacity and much better reversibility than the sample prepared by the traditional solid-state reaction

9

Synthesis, rheology and forming of Y-Ba-Cu-O ceramics  

International Nuclear Information System (INIS)

A chemical synthesis route is discussed which results in a low- temperature precursor to Y-Ba-Cu-O ceramics; it is based on use of molten Ba(OH)2·8H2O flux. Two different chemical systems have been examined; the first one, based on nitrate salts, has been demonstrated to be a viable precursor material for tape casting and extrusion; the second, made from acetate salts, has been used for powder synthesis and extrusion. Rheology of pastes shows that their flow may be fit to either Bingham Plastic or Hershel- Bulkley models. Yield stress is controlled in both pastes by volume fraction solids. Viscosity also follows solids loading in the paste. Shear thinning is controlled by colloidal nature of precursor. The paste has colloidal microstructure. Comparison of concentric cylinder rheometry and piston extrusion rheometry shows order of magnitude differences in yield stress, resulting from the test method and paste dilation

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Synthesis, rheology and forming of Y-Ba-Cu-O ceramics  

Energy Technology Data Exchange (ETDEWEB)

A chemical synthesis route is discussed which results in a low- temperature precursor to Y-Ba-Cu-O ceramics; it is based on use of molten Ba(OH){sub 2}{center_dot}8H{sub 2}O flux. Two different chemical systems have been examined; the first one, based on nitrate salts, has been demonstrated to be a viable precursor material for tape casting and extrusion; the second, made from acetate salts, has been used for powder synthesis and extrusion. Rheology of pastes shows that their flow may be fit to either Bingham Plastic or Hershel- Bulkley models. Yield stress is controlled in both pastes by volume fraction solids. Viscosity also follows solids loading in the paste. Shear thinning is controlled by colloidal nature of precursor. The paste has colloidal microstructure. Comparison of concentric cylinder rheometry and piston extrusion rheometry shows order of magnitude differences in yield stress, resulting from the test method and paste dilation.

Green, T.M.

1993-07-01

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Synthesis of a Magneto-Rheological vehicle suspension system built on the variable structure control approach  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The synthesis of a magneto-rheological vehicle suspension system built on the variable structure control approach is considered in the present work. The suspension is synthesized in order to improve the ride comfort obtained by a standard passive suspension. Although a nominal half-vehicle model wit [...] h rigid body is considered in the synthesis of the suspension, phenomenological models for the MR dampers and for the seat-driver subsystem, along with the flexibility of the vehicle body, are considered in the performance assessment. For comparison purposes, active and magneto-rheological suspensions built on the optimal control approach and an active suspension built on the variable structure control approach are also considered. The numerical results show that the proposed suspension outperforms the passive suspension and presents a performance comparable to that of the active ones when the vehicle body may be assumed as rigid. Besides, when its flexibility is an important issue, a great performance drop may be observed, depending on the road quality, the damper characteristics and the adopted control strategy.

Leonardo Tavares, Stutz; Fernando Alves, Rochinha.

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Synthesis of a Magneto-Rheological vehicle suspension system built on the variable structure control approach  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis of a magneto-rheological vehicle suspension system built on the variable structure control approach is considered in the present work. The suspension is synthesized in order to improve the ride comfort obtained by a standard passive suspension. Although a nominal half-vehicle model with rigid body is considered in the synthesis of the suspension, phenomenological models for the MR dampers and for the seat-driver subsystem, along with the flexibility of the vehicle body, are considered in the performance assessment. For comparison purposes, active and magneto-rheological suspensions built on the optimal control approach and an active suspension built on the variable structure control approach are also considered. The numerical results show that the proposed suspension outperforms the passive suspension and presents a performance comparable to that of the active ones when the vehicle body may be assumed as rigid. Besides, when its flexibility is an important issue, a great performance drop may be observed, depending on the road quality, the damper characteristics and the adopted control strategy.

Leonardo Tavares Stutz

2011-12-01

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Synthesis of and characterization of lithium ceramic electrolytes  

Science.gov (United States)

The depleting fossil fuel reserves, rising oil prices and the need for reduction in CO2 emissions have created an unprecedented impetus for vehicle electrification. Lithium batteries have the highest energy density of the various available battery technologies. They are the most promising battery candidate to enable Hybrid Electric Vehicles (HEVs) and Plug-in Electric Vehicles (PEVs). However, current Li-ion current battery technology is costly and requires a significant increase in energy density to achieve range comparable to conventional gasoline-powered vehicles. Advanced lithium battery technologies such as Li-S and Li-O2 could potentially offer significant improvements in energy density to address the limitations with current Li-ion technology. The implementation of these advanced battery technologies, however, has been limited by the lack of electrolyte technology to enable the use of metallic lithium anodes. Thus, there is a clear and compelling need to develop new electrolyte materials that exhibit the unique combination of fast ion conductivity, stability against lithium, air and moisture. Lithium Lanthanum Titanium Oxide (LLTO) and Lithium Lanthanum Zirconium Oxide (LLZO) have been identified as viable candidates for the advanced battery technologies. However, issues concerning phase purity and densification warrant developing new and novel synthetic techniques. A single step procedure has been developed for the synthesis of Lithium Lanthanum Titanium Oxide (LLTO) membranes. The single step procedure combines phase formation and densification of the ceramic electrolyte in a hot pressing technique. The effect of synthetic technique on relative density, grain structure and ionic conductivity of the LLTO membranes has been explored in detail. The critical step of synthesizing cubic Lithium Lanthanum Zirconium Oxide (LLZO) has been systematically studied through the controlled doping of Al, using X-Ray Diffraction (XRD) analysis. Effects of Li and Al concentration on the crystal structure of LLZO were also studied in detail. Critical dopant concentration of Al to stabilize cubic LLZO was established during the course of this study. Systematic doping studies on the 24c site of La3+ in the primary lattice have also been explored in detail using XRD analysis to improve the ionic conductivity by maintaining the Li sub-lattice free of dopants. It is hypothesized that the supervalent substitutions create Li vacancies in the sub-lattice promoting disorder, thereby stabilizing cubic LLZO. While Ce4+ substitution for La3+ proved to be effective in synthesizing cubic LLZO, precipitation of Ce4+ observed under Backscattered electron (BSE) imaging limited its ionic conductivity. In an effort to develop flexible, solution-based synthetic techniques, two novel processes were established to prepare low dimensional, cubic LLZO powders. Hot pressing of the synthesized LLZO samples yielded high relative density (>95%) ceramic electrolyte membranes. Arrhenius studies using EIS to measure activation energy revealed and empirical relationship between the grain size and activation energy for dense LLZO membranes.

Rangasamy, Ezhiylmurugan

14

Electrolytes and Electrodes for Electrochemical Synthesis of Ammonia  

DEFF Research Database (Denmark)

In order to make Denmark independent of fossil fuels by 2050 the share of renewable energy in electricity production, in particular wind energy, is expected to increase significantly. Since the power output of renewable energy sources heavily fluctuates over time there is a pressing need to find effective energy storage solutions. Production of synthetic fuels (e.g. ammonia) is a promising possibility. Ammonia (NH3) can be an interesting energy carrier, thanks to its high energy density and the existence of well developed storage and transportation technologies. However the present-day production technology is based on the Haber-Bosch process, which is energy intensive and requires large-scale plants. One possible way to produce ammonia from sustainable electricity, nitrogen and hydrogen/water is using an electrochemical cell. This thesis studies a number of electrolytes and electrocatalysts to evaluate their applicability to electrochemical synthesis of ammonia. First a number of potential electrolytes areinvestigated in the temperature range 25-400°C in order to find a proton conductor with a conductivity higher than 10-4 S/cm in dry atmosphere (pH2O < 0.001 atm). The conductivity of materials prepared from FeOOH nanoparticles is measured at 25-40°C between pH2O = 0.037 atm and pH2O < 0.001 atm. The conductivity is low in dry air (10-6-10-8 S/cm), while it can be up to 7·10-3 S/cm in wet air. The conductivity of Y-droped Ti, Si, Sn, Zr, Ce pyrophosphates, Gd-doped cerium phosphate and cerium pyrophosphate - KH2PO4 composite is measured at 100-400°C at pH2O from 0.2 atm to below 0.001 atm. The phase stability and long term conductivity of the compounds with the highest conductivities are investigated, and conductivity is found to depend heavily on pH2O and phosphorus content. High temperature solid state proton conductors are briefly reviewed and defect chemistry and partial conductivities of Y-doped BaZrO3-BaCeO3 solid solutions are studied as a function of temperature, pH2O and chemical compositions by means of defect chemistry modelling. BaCe0.2Zr0.6Y0.2O2.9 (BCZY26) is chosen as electrolyte, and used to fabricate symmetrical cells with composite metal-BCZY26 electrodes. Two metals (iron and molybdenum) are tested as electrocatalysts: the choice is based on the use of catalysts in the Haber-Bosch process and density functional theory calculations. The symmetrical cells are tested at OCV (i.e. without polarization) by impedance spectroscopy in dry H2/N2 and H2/Ar atmospheres, in the temperature range 440-650°C for Mo-BCZY electrodes and 350-500°C fir Fe-BCZY electrodes. No clear evidence of activity of Fe and Mo towards nitrogen reduction to ammonia is found. The kinetics of the electrode reaction (hydrogen oxidation/reduction) at the Mo-BCZY electrode are studied in detail by impedance spectroscopy to identify the electrode processes. Further studies carried out under polarization will be necessary in order to fully assess the potential of Fe and Mo as electrocatalysts for ammonia synthesis.

Lapina, Alberto

2013-01-01

15

Design and synthesis of a crystalline LiPON electrolyte  

Science.gov (United States)

In the course of a computation study of the broad class of lithium phosphorus oxy-nitride materials of interest for solid electrolyte applications, Du and Holzwarth,footnotetextY. A. Du and N. A. W. Holzwarth, Phys. Rev. B 81 184106 (2010) recently predicted a stable crystalline material with the stoichiometry Li2PO2N. The present paper reports the experimental preparation of the material using high temperature solid state synthesis and reports the results of experimental and calculational characterization studies. The so-named SD-Li2PO2N crystal structure has the orthorhombic space group Cmc21 with lattice constants a=9.0692(4) ,=5.3999(2) ,nd c=4.6856(2) å. The structure is similar but not identical to the predicted structure, characterized by parallel arrangements of anionic phosphorus oxy-nitride chains having planar P-N-P-N backbones. Nitrogen 2p? states contribute to the strong bonding and to the chemical and thermal stablility of the material in air up to 600^o C and in vacuum up to 1050^o C. The measured Arrhenius activation energy for ionic conductivity is 0.6 eV which is comparable to computed vacancy migration energies in the presence of a significant population of Li^+ ion vacancies.

Holzwarth, N. A. W.; Senevirathne, Keerthi; Day, Cynthia S.; Lachgar, Abdessadek; Gross, Michael D.

2013-03-01

16

Electrolytes  

Science.gov (United States)

An electrochemical cell consists of two electronic conductors (electrodes) connected via the external circuit (metallic conductor) and separated by an ionic conductor that is called the electrolyte. While the electrodes can be either pure metallic conductors, or mixed electronic and ionic conductors, the separator must be an electronic insulator to prevent a short circuit between the electrodes. In principle, electrolytes can be used in all three physical states: solid, liquid, and gas. Solid electrolytes, e.g., RbAg4I5, are confined to special studies using solid-state electrochemical cells and sensors for gases such as oxygen, hydrogen, sulfur dioxide, and carbon dioxide as well as for ion-selective electrodes [1]. The most common solid electrolyte sensor is a pH electrode in which a glass membrane is an ionic conductor with sodium ions as charge carriers [2

Komorsky-Lovri?, Šebojka

17

The Preparation of Some Novel Electrolytes: Synthesis of Partially Fluorinated Alkanesulfonic Acids as Potential Fuel Cell Electrolytes.  

Science.gov (United States)

The objective of this research was to prepare some strong acids for evaluation by Fort Belvoir as potential fuel cell electrolytes. The major acid, other than phosphoric, H3PO4, currently under investigation by Fort Belvoir as a fuel cell electrolyte is T...

C. Bunyagidj, H. Pietrowska, M. H. Aldridge

1979-01-01

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Synthesis of Single Phase Hg-1223 High Tc Superconducting Films With Multistep Electrolytic Process  

CERN Document Server

We report the multistep electrolytic process for the synthesis of high Tc single phase HgBa2Ca2Cu3O8+? (Hg-1223) superconducting films. The process includes : i) deposition of BaCaCu precursor alloy, ii) oxidation of BaCaCu films, iii) electrolytic intercalation of Hg in precursor BaCaCuO films and iv) electrochemical oxidation and annealing of Hg-intercalated BaCaCuO films to convert into Hg1Ba2Ca2Cu3O8+? (Hg-1223). Films were characterized by thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrolytic intercalation of Hg in BaCaCuO precursor is proved to be a novel alternative to high temperature-high pressure mercuration process. The films are single phase Hg-1223 with Tc = 121.5 K and Jc = 4.3 x 104 A/cm2.

Shivagan, D D; Ekal, L A; Pawar, S H

2003-01-01

19

RHEOLOGICAL PHASE SYNTHESIS AND CHARACTERIZATION OF MICRO-SIZED Li4Ti5O12  

Directory of Open Access Journals (Sweden)

Full Text Available Zero-strain anode material of Li4Ti5O12 for lithium ion battery was successfully synthesized via the rheological phase reaction (RPR method. The as-prepared powders were characterized by means of powder X-ray diffraction (XRD, scanning electron microscope (SEM and particle size distribution analysis (PSD, and the electrochemical properties of the powders were evaluated by the galvanostatic discharge test and cyclic voltammetry (CV. The results revealed that well-crystallized uniform micro-sized Li4Ti5O12 powders were obtained at 800°C for different calcination times via the simple template-free rheological phase route. Among these RPR-derived Li4Ti5O12 powders, one synthesized at 800°C for 22 h displays the initial discharge capacity of 184.3 mAh/g and excellent characteristic of cyclic voltammetry.

LINGLING XIE

2010-01-01

20

The influence of homogeneous electrolyte composition on microplasma synthesis and characteristics of Fe-containing coatings on A1050 alloy  

Science.gov (United States)

In this study the influence of the iron complexes and sodium metasilicate concentrations on the microstructure, thickness and total iron content in the microplasma coatings are reported. The microplasma synthesis of iron containing coatings on A1050 aluminum alloy at the alternative current is able to be controlled by the electrolyte composition variation. The coatings were obtained in electrolytes within the range of concentrations 0-0.05 M for sodium metasilicate and 0.01-0.04 M for iron EDTA complexes. The synthesis process was studied by the analysis of the anodic and cathodic voltage-time curves behavior, chemical composition of the coatings, their thickness and phase composition.

Rogov, A. B.; Slonova, A. I.; Mironov, I. V.

2013-12-01

 
 
 
 
21

Design and synthesis of new electrolyte systems for lithium-ion batteries  

Science.gov (United States)

Rechargeable lithium-ion batteries are extensively used in consumer electronic products, including laptop computers, cellular phones, cameras, camcorders, and medical devices. They have great potential for application in electric and hybrid electric vehicles by virtue of their high energy and power density. Research and development in this direction have been focused all around the globe. The major challenges include the higher cost, safety issues related to the solvents, and conductivities at lower ambient temperature of the solvent-free solid polymer electrolyte (SPE) systems. In this dissertation, three different approaches are presented to achieve an improved electrolyte system for lithium-ion batteries. A plasticizer was synthesized and incorporated into a conventional poly(ethylene oxide) (PEO)-based solid polymer electrolyte system. The ambient temperature ionic conductivity observed at room temperature was noteworthy, due to the decrease of the glass transition temperature of the polymer. Secondly, a branched polymer was synthesized and used as the base matrix in SPEs. Polymers with a higher order of branching remained undissolved in common organic solvents, thereby limiting the scope of their use for making films for the study. The ones with a lower order of branching exhibited ionic conductivities comparable to regular PEO-based electrolytes. The third and most successful approach involved the strategic design and synthesis of a series of low lattice energy lithium salts and their chemical, thermal and electrochemical characterization. In this methodology, the two-to-three step synthetic strategy involved chlorosulfonation of an activated aromatic ring, reaction of the corresponding sulfonyl chloride with trifluoromethanesulfonamide in the presence of triethylamine as a base, followed by lithiation of the resulting triethylammonium salt to generate monolithium, dilithium and scaffolded polylithium salts. The mono- and dilithium salts were tested in electrolyte systems for SPEs, whereas the polylithium salts were characterized as potential candidates for liquid electrolyte systems. The tri-lithium salt based on triptycene proved to be the best of the lot. While all of them showed excellent thermal and electrochemical stability, the salt based on triptycene also demonstrated very good ambient temperature conductivity at low concentrations. The cycling characteristics observed, as well as lithium ion transference number measured with this salt, were impressive and equal to or exceed those for the currently best salt, lithium trifluromethanesulfonimide (LiTFSI).

Chakrabarti, Amartya

22

Electrolyte low concentrations effects on the the rheology of water and bentonitic clays basis drilling fluids; Efeito de baixas concentracoes de eletrolitos na reologia de fluidos de perfuracao a base de agua e argilas bentoniticas  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is to study the effect of low electrolytes concentration on the rheology of the water based oil well drilling fluids and bentonite clays from Boa Vista, PB. It were selected seven samples of bentonite clays (four from industry and three from natural polycationic clay treated with concentrated Na{sub 2}CO{sub 3} solution). The drilling fluids were prepared with a concentration of 4.86 % w/w, according to PETROBRAS norms and treated with different CaCl{sub 2} + MgCl{sub 2} concentration. After, the drilling fluids were submitted to a cure for 24 hours and measured apparent viscosity (AV), plastic viscosity (PV) and water loss (WL). To study the effect of the electrolyte on the rheology of the dispersions it was developed a factorial design 2{sup 2} + 3 test in the central point. The results showed that the addition of CaCl{sub 2} + MgCl{sub 2} caused a degradation of the drilling fluids prepared with industrialized clays, as showed by the decrease in AV and PV and great increase in WL. Also, it was observed an increase in AV and a decrease in PV in the drilling fluids prepared with natural clays treated with Na{sub 2}CO{sub 3}, conducting a flocculated-gel state. (author)

Amorim, Luciana Viana [Universidade Federal, Campina Grande, PB (Brazil). Engenharia de Processos]. E-mail: lucianaa@labdes.ufpb.br; Viana, Josiane Dantas; Farias, Kassie Vieira; Lira, Helio de Lucena; Ferreira, Heber Carlos [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Engenharia de Materiais]. E-mail: josianedantas@bol.com.br; kassievieira@bol.com.br; helio@dema.ufpb.br; heber@dema.ufpb.br; Franca, Kepler Borges [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Engenharia Quimica]. E-mail: kepler@labdes.ufpb.br

2003-07-01

23

Reactions with ZrO(NO3)2 in the synthesis of solid electrolytes of the NASICON type  

International Nuclear Information System (INIS)

The process of NASICON solid phase synthesis is studied in detail. Solid phase reactions during the synthesis of solid electrolytes of the NASICON type taking place with zirconium dinitrate-oxide end at 300-400 deg C,i.e.before the teransition of appearing zirconium dioxide into the stable monoclinic modification The presense of the nitrate group brings about the decrease in the temperature of intensive decomposition of sodium carbonate and nitrate and sodium zirconate formation close to 180 deg C

24

Synthesis and Rheological Characterization of Water-Soluble Glycidyltrimethylammonium-Chitosan  

Science.gov (United States)

In this study, chitosan (CS) grafted by glycidyltrimethylammonium chloride (GTMAC) to form GTMAC-CS was synthesized, chemically identified, and rheologically characterized. The Maxwell Model can be applied to closely simulate the dynamic rheological performance of the chitosan and the GTMAC-CS solutions, revealing a single relaxation time pertains to both systems. The crossover point of G? and G? shifted toward lower frequencies as the CS concentration increased but remained almost constant frequencies as the GTMAC-CS concentration increased, indicating the solubility of GTMAC-CS in water is good enough to diminish influence from the interaction among polymer chains so as to ensure the relaxation time is independent of the concentration. A frequency–concentration superposition master curve of the CS and GTMAC-CS solutions was subsequently proposed and well fitted with the experimental results. Finally, the sol-gel transition of CS is 8.5 weight % (wt %), while that of GTMAC-CS is 20 wt %, reconfirming the excellent water solubility of the latter. PMID:25419996

Rwei, Syang-Peng; Chen, Yu-Ming; Lin, Wen-Yan; Chiang, Whe-Yi

2014-01-01

25

Synthesis and rheological characterization of water-soluble glycidyltrimethylammonium-chitosan.  

Science.gov (United States)

In this study, chitosan (CS) grafted by glycidyltrimethylammonium chloride (GTMAC) to form GTMAC-CS was synthesized, chemically identified, and rheologically characterized. The Maxwell Model can be applied to closely simulate the dynamic rheological performance of the chitosan and the GTMAC-CS solutions, revealing a single relaxation time pertains to both systems. The crossover point of G' and G" shifted toward lower frequencies as the CS concentration increased but remained almost constant frequencies as the GTMAC-CS concentration increased, indicating the solubility of GTMAC-CS in water is good enough to diminish influence from the interaction among polymer chains so as to ensure the relaxation time is independent of the concentration. A frequency-concentration superposition master curve of the CS and GTMAC-CS solutions was subsequently proposed and well fitted with the experimental results. Finally, the sol-gel transition of CS is 8.5 weight % (wt %), while that of GTMAC-CS is 20 wt %, reconfirming the excellent water solubility of the latter. PMID:25419996

Rwei, Syang-Peng; Chen, Yu-Ming; Lin, Wen-Yan; Chiang, Whe-Yi

2014-01-01

26

Electrocatalytic study of ammonia synthesis and methane dimerization in high temperature solid electrolyte cells  

Science.gov (United States)

The present report covers the first year of the three year project. The work is funded 50-50 by the National Science Foundation and the Department of Energy. The NSF support started on February 15, 1989 while the DOE support started on September 15, 1989. This created some minor difficulties in the budget distribution but hopefully within the second year everything will be smoothed out. The personnel involved in the project includes the principal investigator (M. Stoukides) who devotes 25 to 30 percent of his time during the year. Douglas Eng is going to work as a research scientist in the project on a full-time basis. Dr. Eng worked under the P.I. in the area of methane oxidation and he is probably the most qualified person for this position. Mr. Po-Hung Chiang has started working as a Ph.D. candidate in the H(sup +) solid electrolyte aided study of methane dimerization. Mr. Hyatham Algahtang, a new graduate student, is the most favorite candidate for the study of NH3 synthesis. He is already examining preliminary aspects of the project. Most of the equipment required for this research was in operating condition in the laboratory. Additional equipment purchased included a Lindberg furnace that could reach as high as 1500 C for fabrication of the solid electrolyte and a Rosemount Analytical hydrogen analyzer for continuous measurement of the concentration of hydrogen on either the cathodic or the anodic side.

Stoukides, M.

1990-01-01

27

Hot-pressed Ag+ Ion Conducting Glass-Polymer Electrolytes: Synthesis and Battery Application  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english Synthesis of new Ag+ ion conducting glass-polymer electrolytes (GPEs): (1-x) PEO: x [0.75(0.75AgI:0.25AgCl):0.25(Ag2O:P2O5)], where 0 [...] )], with conductivity (?) ? 6.0 × 10-6 S cm-1, was identified from the compositional dependent conductivity studies and this has been referred to as the Optimum Conducting Composition (OCC). Approximately three orders of conductivity enhancement have been achieved in GPE OCC from that of the pure polymer PEO. The glass-polymer complexation has been confirmed by SEM and DSC analysis. Ion transport parameters viz. ionic conductivity (?), ionic mobility (?), mobile ion concentration (n) and ionic transference number (tion) have been characterized using different experimental techniques. Solid-state polymeric batteries were fabricated using GPE OCC as electrolyte and the cell-potential discharge characteristics were studied under different load conditions at room temperature.

Angesh, Chandra.

2012-07-01

28

Synthesis of yttria-doped zirconia anodes and calcium-doped ceria electrolyte to fuel cell  

International Nuclear Information System (INIS)

From the pursuit of lower operating temperature of fuel cells solid oxide was used polymeric precursor for the synthesis of reactive powder compositions Zr0,92Y0,08O2 for the anode and Ce0,88Ca0,12O2 for the electrolyte. The solutions were prepared using the metal in much of the composition and citric acid molar ratio of 1:3, under stirring at 60 deg C/1 h. The mixture of metallic citrates was subjected to agitation at a temperature of 80 deg C which was added ethylene glycol in the ratio 60:40 by weight citric acid / ethylene glycol, to form a resin that was pre-calcined at 300 deg C/3 h for to form the expanded resin. The powders were disaggregated in a mortar, screened and calcined at 400, 600 and 800 deg C/2 h. The powders were characterized by standard X-ray diffraction. (author)

29

Synthesis, characterization and rheological property of biphenyl-based polyarylene ether nitrile copolymers  

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Full Text Available The high molecular weight biphenyl-based polyarylene ether nitrile copolymers were synthesized by nucleophilic substitution reaction of 2,6-dichlorobenzonitrile (DCBN with varying molar ratios of 4,4’-dihydroxybiphenyl (BP and hydroquinone (HQ. The BP content of the copolymers has influence on glass transition temperature (Tg, initial decomposition temperature (Tid, mechanical properties and the crystallinity. All the copolymers could be dissolved in NMP, DMF and DMAc on heating, and were stable up to 450°C with a high char yield above 50% at 800°C in nitrogen atmosphere. The glass transition temperature, the melting temperature and tensile strength of copolymers were found to increase with increase in concentration of the BP units in the polymer. The dynamical viscosity and the storage modulus have been influenced by the BP concentration, frequency, temperature and time. This rheological results show that these copolymers have best thermoplastic processability and stability at 300–400°C.

2007-08-01

30

Synthesis and characterization of polyphosphazenes as polymer electrolytes for secondary lithium battery applications  

Science.gov (United States)

This thesis describes the synthesis and characterization of polyphosphazenes as polymer electrolytes for secondary lithium battery applications. The polyphosphazenes that were synthesized include (a) species with linear and branched oligo(oxyethylene) side groups, (b) examples which incorporate crown ethers of various sizes, and (c) polymers which include sulfone or sulfoxide functional groups. Additional work involved the investigation of the factors that limit the cycle life of lithium-polymer secondary batteries. New polymers that contain either linear or branched oligo(oxyethylene) side-chains were synthesized. The polymers that bear linear side-chains have low glass transition temperatures and poor physical properties. The polymers with branched side-chains have similar glass transition temperatures, but have significantly improved bulk dimensional stabilities. The two systems have comparable ionic conductivities. Phosphazene polymers, bearing either 12-crown-4, 15-crown-5, or 18-crown-6 groups, either as single-substituent polymers or with 2-(2sp'-methoxyethoxy)ethoxy cosubstituents, were synthesized. The polymers in which all the side groups are crown ether units generate relatively low ionic conductivities at ambient temperatures. The ambient temperature ionic conductivity of the cosubstituent polyphosphazenes, as well as of MEEP, when complexed with MClOsb4 (M = Li, Na, K, Rb, Cs), was measured. The ionic conductivity is reduced when a favorable 1:1 or 2:1 crown ether-cation complex is formed. There is an increased glass transition temperature when a favorable 2:1 complex is formed. A synthetic method for the introduction of sulfone or sulfoxide functional groups into polyphosphazenes has been developed. This procedure involves the prior introduction of thioether groups followed by oxidation by Hsb2Osb2 or m-chloroperbenzoic acid. Oxidation of the sulfur atom results in polymers with relatively high glass transition temperatures. The potential of these materials as polymer electrolytes, both in the solid state or in systems with added propylene carbonate, was explored. The compatibility of polyphosphazene electrolytes with manganese (IV) oxide-based cathodes was investigated. Laminates of a solid polymer electrolyte (SMEP) between two MnOsb2-based intercalation cathodes were constructed. The cathodes were fabricated by solvent-casting and compression techniques. Both lambda-MnOsb2 and gamma-MnOsb2 were used. MEEP was the cathode binder material. Charge cycling was carried out and cell performance monitored by electrochemical impedance spectroscopy.

Olmeijer, David L.

31

Synthesis, morphology and rheology of core-shell silicone acrylic emulsion stabilized with polymerisable surfactant  

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Full Text Available Core-shell silicone acrylic emulsions with 3-methacryloxypropyl trimethoxysilane (MPTS in the shell were prepared by seeded polymerization with the assistance of polymerisable maleate surfactant (MT. Fourier transform infrared (FT-IR demonstrated the incorporation of polymerisable surfactant in copolymer. It was found that small amount of octadecyl acrylate was beneficial to emulsion stability with decreasing the particle size from 194.6 to 165.7 nm. It was also found that the particle size increased from 165.7 to 242.9 nm with the increase of MPTS concentration. Furthermore, rheological measurement indicated that the emulsion was endowed with pseudoplasticity. At low shear rate, marginal reduction in viscosity was detected when MPTS concentration increased to 2%, while great increase in viscosity was observed with higher MPTS concentration, the interaction force among emulsion particles became the predominant factor instead of particle size. In addition, better water resistance was observed when MT concentration was lower than 1.5%, and MPTS concentration higher than 2%. Moreover, surface roughness was increased with MPTS addition, the crosslinking among core and shell reconstructed the surface morphology of film.

2010-11-01

32

Influence of a singly-charged electrolyte on the efficiency of solubilization compositions for the template synthesis of silica nanoadsorbents  

Science.gov (United States)

Silica mesoporous materials of the MSM-41 type were obtained by bitemplate (solubilization) synthesis in an aqueous electrolyte solution (sodium chloride) using sodium metasilicate as the source of silica, alkylpyridinium halogenides as the micelle-forming surfactants, and monoethanoamides of n-aliphatic acids or trialkylphosphine oxides as the solubilizers. The influence of a singly-charged electrolyte and a solution of bitemplate composition on the X-ray structure and structure adsorption characteristics of the synthesized materials was analyzed. It was shown that mesoporous silica with better spatial structure and high specific surface values ( S sp = 1170-1200 m2/g, ? V = 0.80-1.10 cm3/g, D meso = 3.5-4.1 nm) are formed under the investigated conditions of synthesis when alkylpyridinium halogenides with a length of a hydrocarbon radical consisting of 10, 12, or 14 carbon atoms are used.

Yaroshenko, N. A.; Trofimenko, S. I.; Govorek, Ya.; Zub, Yu. L.

2010-08-01

33

Synthesis of ozone from air via a polymer-electrolyte-membrane cell with a doped tin oxide anode  

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The generation of ozone from air using an electrochemical cell consisting of an air cathode, a polymer-electrolyte-membrane (PEM), and a doped tin oxide anode is reported. This synthesis is environmentally friendly compared to the conventional high-voltage corona discharge process since NOx formation is eliminated; a higher ozone concentration is generated; and lower energy may be required. © The Royal Society of Chemistry 2006.

Wang, Yh; Cheng, S.; Chan, Ky

2006-01-01

34

Synthesis and ceramic processing of zirconia alumina composites for application as solid oxide fuel cell electrolytes  

International Nuclear Information System (INIS)

The global warmness and the necessity to obtain clean energy from alternative methods than petroleum raises the importance of developing cleaner and more efficient systems of energy generation, among then, the solid oxide fuel cell (SOFC). Cubic stabilized zirconia (CSZ) has been the most studied material as electrolyte in SOFC, due to its ionic conductivity and great stability at operation conditions. However, its low fracture toughness difficulties its application as a thin layer, what could lead to an improvement of cell efficiency. In this sense, the alumina addition in CSZ forms a composite, which can shift its mechanical properties, without compromising its electrical properties. In this work, coprecipitation synthesis route and ceramic processing of zirconia-alumina composites were studied, in order to establish optimum conditions to attain high density, homogeneous microstructure, and better mechanical properties than CSZ, without compromising ionic conductivity. For this purpose, composites containing up to 40 wt % of alumina, in a 9 mol % yttria-stabilized zirconia (9Y-CSZ) matrix were evaluated. In order to optimize the synthesis of the composites, a preliminary study of powder obtaining and processing were carried out, at compositions containing 20 wt % of alumina, in 9Y-CSZ. The ceramic powders were characterized by helium picnometry, X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, differential scanning calorimetry, granulometry by laser diffraction and gas adsorption (BET). The characterization of sinterized compacts were performed by X-ray diffraction, scanning electron microscopy, optical microscopy, density measurements, Vickers indentation and impedance spectroscopy. The obtained results show that the alumina addition, in the 9Y-CSZ matrix powders, raises the specific surface area, promotes deagglomeration of powders and elevates the oxides crystallization temperature, requiring higher energetic thermal treatments to attain high densities. In relation to the sintered products, it was confirmed the excellent homogeneity and crystallinity of microstructure provided by the chosen route, the restriction of grain growth by alumina addition, raise of hardness and fracture toughness, and higher ionic conductivity, even tough a lower bulk conductivity. These results indicate that the addition of 5 wt % alumina in CSZ matrix allows the application of this material as solid oxide fuel cell electrolytes, due to its better fracture toughness and ionic conductivity, compared to yttria-stabilized cubic zirconia ceramics. (author)

35

Synthesis and examination of electrolytic sodium-vanadium oxide compounds intended for cathodes of lithium batteries: the mechanism of formation of electrolytic bronze ?-NaxV2O5  

International Nuclear Information System (INIS)

For ascertaining the mechanism of electrolytic sodium-vanadium oxide bronze e-NaxV2O5 formation, which had been previously synthesized from acid vanadyl sulfate electrolyte, synthesis of ?-bronze i-NaxV2O5 was performed by electrolytic (e) oxide e-V2O5 exposure in the same sodium-containing electrolyte without current and with subsequent annealing of the exposed sample. The investigation, conducted by the methods of IR spectroscopy thermal and X-ray phase analyses, permitted ascertaining the identity of two modification of ?-bronze (e-NaxV2O5, i-NaxV2O5) and the proof of ion-exchange mechanism realization of electrolytic precursors of ?-bronze NaxV2O5 was found

36

Synthesis of carbon-supported titanium oxynitride nanoparticles as cathode catalyst for polymer electrolyte fuel cells  

International Nuclear Information System (INIS)

Highlights: • A sol–gel route for the synthesis of rutile TiO2 was modified to synthesize TiOxNy-C. • N atoms were doped into TiOx nanoparticles solely by the heat-treatment under N2 gas. • The N2-treatment produced sites more active toward ORR compared with NH3-treatment. • TiOx doped with a small amount of N atoms are suggested to be responsible for ORR. -- Abstract: For use as the oxygen reduction reaction (ORR) catalyst in polymer electrolyte fuel cell cathodes, carbon-supported titanium oxynitride (TiOxNy-C) nanoparticles with a size of approximately 5 nm or less were synthesized without using NH3 gas. A sol–gel route developed for the synthesis of pure rutile TiO2 nanopowders was modified to prepare the carbon-supported titanium oxide nanoparticles (TiOx-C). For the first time, N atoms were doped into TiOx solely by heating TiOx-C under an inexpensive N2 atmosphere at 873 K for 3 h, which could be due to carbothermal reduction. The TiOx-C powder was also heated under NH3 gas at various temperatures (873–1273 K) and durations (3–30 h). This step resulted in the formation of a TiN phase irrespective of the heating conditions. Both N2- and NH3-treated TiOxNy-C did not crystallize well; however, the former showed a mass activity more than three times larger than that of the latter at 0.74 V versus the standard hydrogen electrode. Thus, titanium oxide nanoparticles doped with a small amount of N atoms are suggested to be responsible for catalyzing ORR in the case of N2-treated TiOxNy-C

37

Synthesis of Bismuth Oxide Based Material for Sofc Electrolyte with Yttria addictive and their Characterization  

International Nuclear Information System (INIS)

Research on synthesis of solid electrolyte SOFC based on bismuth oxide and yttrium oxide as dopant has been done through pressing technique process, where bismuth oxide and yttrium oxide chloride are as its raw materials. Both of materials are dissolved and then co-precipitated to get a mixture material which has very small grain size (nm), continued with sintering process with temperature variation of 1000 oC, 1050 oC, 1100oC and holding time of 1 hour. The result of this process is analyzed by dilatometer at room temperature until 1000 oC, which gave the coefficient of thermal expansion of 11.9 x 10-6/ oC to 13.4 x 10-6/ oC. The measurement of density by Archimedes method (ASTM D 792), gave the value of density of 6.2 g/cm3 until 7.6 g/cm3. Using ASTM C20 procedure, the porosity measured are 18.3 % until 0.2 %. The Impedance complex spectroscopy and Frequency Response Analyzer (FRA) Solartron 1260 is used for measuring ionic conductivity. The ionic conductivity are increasing on temperature range 500 oC until 800 oC, which are 5 x 10-3/ ?.cm to 1.8 x I0-1/ ?.cm. The yttrium oxide dopant increased bismuth oxide ionic conductivity for 10 times until 1000 times. (author)

38

Synthesis and Characterization of Cross-linked Polymer Electrolyte Membranes for Supercapacitor  

Science.gov (United States)

Cross-linked polyvinyl alcohol (PVA) electrolyte membranes have been synthesized by using a solution casting method. In this study, PVA was blended with oxidative cross-linked agent (zinc acetate) and nano-sized silica as filler to stabilize PVA matrix and enhance conductivity. The cross-linked membranes were immersed into lithium hydroxide (LiOH) aqueous solution to increase their ionic conductivity. Two techniques were used to characterize the resulted membranes including Fourier transform infra red (FTIR) and AC impedance spectroscopies. The results showed that absorption peaks of C-O-C group and Si-O-Si are presence in the FTIR spectra attributed to the cross-linking process. Impedance spectra indicated that the contribution of ionic dopant (LiOH) to enhance conductivity is insignificant. The highest conductivity of the studied cross-linked PVA membrane is 1.34×10-3 S cm-1 corresponding to 5% LiOH dopant concentration of cross-linked PVA-zinc acetate-nano silica membrane. The present study also suggested that the solution casting is appropriate for cross-linked membrane synthesis.

Rosi, Memoria; Ekaputra, Muhamad Prama; Abdullah, Mikrajuddin; Khairurrijal

2010-10-01

39

Molecular rheology of branched polymers: decoding and exploring the role of architectural dispersity through a synergy of anionic synthesis, interaction chromatography, rheometry and modeling.  

Science.gov (United States)

An emerging challenge in polymer physics is the quantitative understanding of the influence of a macromolecular architecture (i.e., branching) on the rheological response of entangled complex polymers. Recent investigations of the rheology of well-defined architecturally complex polymers have determined the composition in the molecular structure and identified the role of side-products in the measured samples. The combination of different characterization techniques, experimental and/or theoretical, represents the current state-of-the-art. Here we review this interdisciplinary approach to molecular rheology of complex polymers, and show the importance of confronting these different tools for ensuring an accurate characterization of a given polymeric sample. We use statistical tools in order to relate the information available from the synthesis protocols of a sample and its experimental molar mass distribution (typically obtained from size exclusion chromatography), and hence obtain precise information about its structural composition, i.e. enhance the existing sensitivity limit. We critically discuss the use of linear rheology as a reliable quantitative characterization tool, along with the recently developed temperature gradient interaction chromatography. The latter, which has emerged as an indispensable characterization tool for branched architectures, offers unprecedented sensitivity in detecting the presence of different molecular structures in a sample. Combining these techniques is imperative in order to quantify the molecular composition of a polymer and its consequences on the macroscopic properties. We validate this approach by means of a new model asymmetric comb polymer which was synthesized anionically. It was thoroughly characterized and its rheology was carefully analyzed. The main result is that the rheological signal reveals fine molecular details, which must be taken into account to fully elucidate the viscoelastic response of entangled branched polymers. It is important to appreciate that, even optimal model systems, i.e., those synthesized with high-vacuum anionic methods, need thorough characterization via a combination of techniques. Besides helping to improve synthetic techniques, this methodology will be significant in fine-tuning mesoscopic tube-based models and addressing outstanding issues such as the quantitative description of the constraint release mechanism. PMID:24705637

van Ruymbeke, E; Lee, H; Chang, T; Nikopoulou, A; Hadjichristidis, N; Snijkers, F; Vlassopoulos, D

2014-07-21

40

Synthesis and investigation of electrolytic sodium-vanadium oxide compounds for cathodes of lithium batteries: the production of compounds with stable initial characteristics  

International Nuclear Information System (INIS)

Heterogeneous vanadium oxide compounds were prepared during electrolysis of vanadyl sulfate solution in the presence of sodium ions. The limits of process parameters for synthesis of electrolysis products with stable initial electrochemical characteristics were ascertained. It is shown that the presence of sodium ions gives rise to the deposit adhesion o substrate. Electrochemical properties of the electrolytic deposits depend on the content of sodium ions in deposition electrolyte and subsequent thermal treatment of the deposit. Specific discharge capacity of electrolytic Na-vanadium oxide compounds may reach 320 Ah/kg in case of discharge up to 2.0 V at a density of 100 ?A/cm2

 
 
 
 
41

Synthesis and electrochemical characterization of PEO-based polymer electrolytes with room temperature ionic liquids  

International Nuclear Information System (INIS)

New gel polymer electrolytes containing 1-butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide (BMPyTFSI) ionic liquid are prepared by solution casting method. Thermal and electrochemical properties have been determined for these gel polymer electrolytes. The addition of BMPyTFSI to the P(EO)20LiTFSI electrolyte results in an increase of the ionic conductivity, and at high BMPyTFSI concentration (BMPy+/Li+ = 1.0), the ionic conductivity reaches the value of 6.9 x 10-4 S/cm at 40 oC. The lithium ion transference numbers obtained from polarization measurements at 40 oC were found to decrease as the amount of BMPyTFSI increased. However, the lithium ionic conductivity increased with the content of BMPyTFSI. The electrochemical stability and interfacial stability for these gel polymer electrolytes were significantly improved due to the incorporation of BMPyTFSI

42

Synthesis and electrochemical characterization of PEO-based polymer electrolytes with room temperature ionic liquids  

Energy Technology Data Exchange (ETDEWEB)

New gel polymer electrolytes containing 1-butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide (BMPyTFSI) ionic liquid are prepared by solution casting method. Thermal and electrochemical properties have been determined for these gel polymer electrolytes. The addition of BMPyTFSI to the P(EO){sub 20}LiTFSI electrolyte results in an increase of the ionic conductivity, and at high BMPyTFSI concentration (BMPy{sup +}/Li{sup +} = 1.0), the ionic conductivity reaches the value of 6.9 x 10{sup -4} S/cm at 40 C. The lithium ion transference numbers obtained from polarization measurements at 40 C were found to decrease as the amount of BMPyTFSI increased. However, the lithium ionic conductivity increased with the content of BMPyTFSI. The electrochemical stability and interfacial stability for these gel polymer electrolytes were significantly improved due to the incorporation of BMPyTFSI. (author)

Cheng, Hu; Zhu, Changbao; Huang, Bin; Lu, Mi; Yang, Yong [State Key Laboratory for Physical Chemistry of Solid Surface, Department of Chemistry, Xiamen University, Xiamen 361005 (China)

2007-05-25

43

Synthesis and Characterization of Triazolium Iodide Ionic Liquid Electrolyte for Dye Sensitized Solar Cells  

Energy Technology Data Exchange (ETDEWEB)

Imidazolium iodide compounds have been utilized in the electrolytes for dye sensitized solar cells (DSSC). Most of the investigations with these compounds focus on the formulation of eutectic mixtures that promote efficient dissociation and diffusion of the iodide and triiodide species. Facile alternative synthetic approaches such as click chemistry (Huisgen 3+2 dipolar cycloaddition reaction) can be utilized to broaden the scope of electrochemically stable promising materials for novel electrolyte systems. Here, we report the first example of a triazolium functionalized cyclic siloxane that can be used as an electrolyte component in solvent-based DSSCs. The devices fabricated with this new triazolium salt in the electrolyte yielded short circuit current densities (26 mA/cm{sup 2}), as well as power conversion efficiencies of 8%, these values are comparable to those obtained for imidazolium salt analogues.

Kokil, Akshay; Renna, A.; Kumar, Jayant; Granados-Focil, S.

2011-01-01

44

Synthesis of a novel imidazolium-based electrolytes and application for dye-sensitized solar cells  

International Nuclear Information System (INIS)

A series of new imidazolium-based oligomers with different length of a poly(ethylene glycol) moiety as a linker were synthesized and studied as electrolytes for dye-sensitized solar cell (DSSC). These oligomeric molecules are expected to have an intra- or inter-molecular hydrogen bonding interaction through its urethane and urea bonds. They can be used to prepare the liquid-type electrolytes for DSSC by dissolving them into conventional solvent system or to develop solvent-free electrolytes by incorporating an extra redox mediator and other functional materials together as additives. It was found that these oligomers could replace the cationic component of the conventional electrolytes and became the source of redox species when iodine is added. The photocurrent-voltage characteristics of DSSCs with the electrolytes containing these oligomers demonstrated that they can successfully replace the conventional ionic liquid-type electrolytes such as 1-methyl-3-propyl imidazolium iodide (PMII) in 3-methoxypropionitrile (MPN) if the length of the linker is optimized.

45

Synthesis and characterization of amorphous poly(ethylene oxide)/poly(trimethylene carbonate) polymer blend electrolytes  

International Nuclear Information System (INIS)

Solid polymer electrolytes (SPEs) have been proposed as substitutes for conventional non-aqueous electrolytes in various electrochemical devices. These promising materials may be of interest in various practical devices including batteries, sensors and electrochromic displays as they can offer high performance in terms of specific energy and specific power (batteries), safe operation, form flexibility in device arquitecture and low manufacturing costs. Many different host polymers have been characterized over the last 30 years, however a relatively un-explored strategy involves the use of interpenetrating blends incorporating two or more polymers. Electrolyte systems based on interpenetrating blends of known host polymers, poly(ethylene oxide) and poly(trimethylene carbonate), doped with lithium perchlorate, were prepared by co-dissolution in acetonitrile. This combination of polymer components results in the formation of a material that may be applicable in batteries and electrochromic devices. The results of characterization of polymer electrolyte systems based on interpenetrating blends of amorphous poly(ethylene oxide) and poly(trimethylene carbonate) host matrices, with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as guest salt, are described in this study. Electrolytes with compositions of n between 5 and 15 (where n represents the total number of cation-coordinating units per lithium ion) were obtained as flexible, transparent and free-standing films that were characterized by measurements of conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry.

46

Facile synthesis of polypyrrole nanofiber and its enhanced electrochemical performances in different electrolytes  

Directory of Open Access Journals (Sweden)

Full Text Available A porous nanocomposite based on polypyrrole (PPy and sodium alginate (SA has been synthesized by easy, inexpensive, eco-friendly method. As prepared nanocomposite showed fibrillar morphology in transmission electron microscopic (TEM analysis. The average diameter of ~100 nm for the nanofibers was observed from scanning electron microscopic (SEM analysis. As prepared nanofiber, was investigated as an electrode material for supercapacitor application in different aqueous electrolyte solutions. PPy nanofiber showed enhanced electrochemical performances in 1M KCl solution as compared to 1M Na2SO4 solution. Maximum specific capacitance of 284 F/g was found for this composite in 1 M KCl electrolyte. It showed 76% specific capacitance retention after 600 cycles in 1 M KCl solution. Electrochemical Impedance Spectra showed moderate capacitive behavior of the composite in both the electrolytes. Further PPy nanofiber demonstrated higher thermal stability as compared to pure PPy.

C. K. Das

2012-12-01

47

Synthesis and properties of a cation-conducting, high temperature polymer electrolyte  

Energy Technology Data Exchange (ETDEWEB)

A new class of polymer electrolyte, high temperature polymer electroltyes, as an electrolyte in high discharge rate batteries is proposed. As an initial effort in the development of these materials, sodium and lithium salts of sulfonated poly(p-phenyleneterephtalamide) have been prepared. DSC and electrical conductivity studies have been performed on these films. The conductivity exhibits Arrhenius behavior over the temperature range in which they are thermally stable (180-240 C) with the material containing sodium being more conductive than those containing lithium. Although the electrical performance of these materials is inadequate from a practical standpoint, it is suggested that with additional development these materials could function as electrolytes for high discharge rate batteries. (orig.)

Okamoto, Y. (Dept. of Chemistry, Polytechnic Univ., Brooklyn, NY (United States)); Xu, Z.S. (Dept. of Chemistry, Polytechnic Univ., Brooklyn, NY (United States)); McLin, M.G. (Physics Dept., U.S. Naval Academy, Annapolis, MD (United States)); Fontanella, J.J. (Physics Dept., U.S. Naval Academy, Annapolis, MD (United States)); Pak, Y.S. (Physics Dept., Hunter Coll. of CUNY, New York (United States)); Greenbaum, S.G. (Physics Dept., Hunter Coll. of CUNY, New York (United States))

1993-03-01

48

Synthesis and electrolytic polymerization of the ethylenedioxy-substituted terthiophene-fullerene dyad.  

Science.gov (United States)

[reaction: see text] Two derivatives of ethylenedioxy-substituted terthiophene-fullerene dyads were newly synthesized as the precursors for polythiophene having fullerene side chains. By electrolytic oxidation of dyad 1, the charm-bracelet type polythiophene, poly-1, was obtained as a purple film, which showed electrochemical activity, electrochromism, and photoelectronic response. PMID:15606086

Yamazaki, Tetsuya; Murata, Yasujiro; Komatsu, Koichi; Furukawa, Kazuaki; Morita, Masao; Maruyama, Norihiko; Yamao, Takeshi; Fujita, Shizuo

2004-12-23

49

Synthesis of nano-sized electrolyte materials of SOFC by gel combustion route  

International Nuclear Information System (INIS)

A typical SOFC operating at high temperature utilizes cubic yttria-stabilized zirconia (YSZ) as the electrolyte because it fulfils several desired criteria (high ionic conductivity, low or nearly zero electronic conductivity and rational strength to stand the mechanical and thermal stresses). High-temperature operation (about 1000 deg C) causes many serious problems, i.e. degradation of the cell performance and a limited choice of materials and so on, hence it is desirable to operate SOFCs at a moderate temperature around 800 deg C. In order to explore alternate electrolytes, other rare earth (La, Nd and Gd) substituted zirconia were prepared by gel combustion and co-precipitation route to produce homogeneous, very fine, crystalline and unagglomerated powders, without the intermediate decomposition step. Most of these electrolyte materials are synthesized using traditional solid state techniques with sintering at 1600-1650 deg C leading to densities of less than 95% which normally reduces ionic conductivity of the electrolytes. The structural characterizations of prepared sample were done by powder XRD and thermal expansion data was generated by dilatometric studies

50

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

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

K. Sownthari

2013-06-01

51

Iodide-conducting polymer electrolytes based on poly-ethylene glycol and MgI2: Synthesis and structural characterization  

International Nuclear Information System (INIS)

A major obstacle for a viable technological development of dye sensitized solar cells (DSSCs) is still the synthesis of a high performance iodide-conducting polymer electrolyte. Here we present a series of eight electrolytic complexes with formula PEG1000/(MgI2)x(I2)y (0.0038 ? x ? 0.5801, 0 ? y ? 0.0636). The synthesis involves the preparation of a disordered form of MgI2 by a metallorganic route, which enables us to dissolve high amounts of salt in the chosen polymer host. The thermal analysis of the resulting polymer electrolytes was performed using modulated differential scanning calorimetry measurements. Vibrational studies were carried out using medium FT-IR, far FT-IR and FT-Raman. The variation of the CO and OH stretching modes in the medium infrared, as a function of the mole-to-mole ratio nMg/nO, was investigated by Gaussian decomposition to provide insight into the polymer–polymer and salt–polymer interactions in these materials. The FT-Raman spectra confirmed and complemented the vibrational assignment. The conductivity study of these systems was performed by electrical spectroscopy in the frequency interval 10 mHz–10 MHz. The direct current conductivity (?DC) profiles versus the reciprocal temperature exhibited a Vögel-Tamman-Fülcher (VTF) behavior. The best ?DC at 50 °C was 5 × 10?5 S cm?1. The overall results indicate the presence of bivalent, monovalent and neutral species, Mg2+, [MgI]+ and MgI2, respectively, which participate in the conduction process. These results are consistent with what was previously observed in PEG400-based systems doped with ?-MgCl2. The presence of at least one Mg site containing a distribution in parameters was observed using 25Mg solid state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The site has been assigned to a Mg complex involving the coordination by oxygen atoms of the polymer backbone.

52

Synthesis of Coral-Like Tantalum Oxide Films via Anodization in Mixed Organic-Inorganic Electrolytes  

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We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two–electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 ...

Yu, Hongbin; Zhu, Suiyi; Yang, Xia; Wang, Xinhong; Sun, Hongwei; Huo, Mingxin

2013-01-01

53

A sol-gel synthesis of polyether-based proton conducting electrolytes  

International Nuclear Information System (INIS)

Proton conducting electrolyte gels composed of short polyether ''tails'' bound to a sol-gel matrix ([MePEG350S(CH2)3SiO3]n) and sulfonated oligomeric methyl polyethylene glycol (MePEG350-SO3H) exhibit dry and unplasticized H+ conductivities of up to 2.3x10-5 S/cm at 50 deg. C under vacuum. Proton conductivities in these electrolyte gels increase with added acid (MePEG350-SO3H). Activation barriers to H+ conductivity were between 20 kJ/mol for 0.25 M MePEG350-SO3H in (MePEG350S(CH2)3SiO3)n, and 38 kJ/mol for the 1.26 M mixture. Air equilibrated conductivities in these materials reached a maximum of 3.4x10-4 S/cm for neat MePEG350-SO3H

54

Synthesis of yttria-doped bismuth oxide powder by carbonate coprecipitation for IT-SOFC electrolyte.  

Science.gov (United States)

Yttria-doped bismuth oxide (YBO) powders were synthesized by ammonium carbonate coprecipitation for the preparation of electrolytes of an intermediate temperature solid oxide fuel cell (IT-SOFC). The starting salts were yttrium and bismuth nitrate. The crystal structures and the morphological characteristics of the particles were analyzed by XRD and SEM, respectively. The ionic conductivity of the sintered pellet was measured by an electrochemical impedance analyzer. The size of the calcined YBO powders were in the range of 20-100 nm as measured by SEM images. The YBO pellets had a face-centered cubic structure, and their crystallite size was about 54-88 nm. The ionic conductivity of the YBO pellets sintered at 800 degrees C was observed to be 2.7 x 10(-1) Scm-(-1) at 700 degrees C. The ball-milling of the YBO powder before it was pelletized was found to have been unrequired probably because of a good sinterability of the YBO powders that was prepared via the ammonium carbonate coprecipitation method. The results showed that the ammonium carbonate coprecipitation process could be used as the cost-efficient method of producing YBO electrolytes for IT-SOFC. PMID:21446553

Lee, J G; Kim, S H; Yoon, H H

2011-01-01

55

Synthesis, characterization and influence of electrolyte solutions on electrical properties of organic-inorganic composite membrane  

Science.gov (United States)

In this work various electrical properties of titanium molybdate composite membrane had been discussed. The membrane was characterized by X-ray diffraction, scanning electron microscopy, particle size analysis and Infra-red spectroscopy. The effective fixed charge density of the membrane was determined by TMS method and it showed the dependence of membrane potential on, the charge on the membrane matrix, porosity and size of permeating ions. The change in membrane capacitance and resistance values with the change in electrolyte concentration and applied frequency had been interpreted in terms of the charges produced in the electrical double layer at the membrane solution interface. The magnitude of membrane capacitance had been found to be dependent on the capacitance of the double layer. In higher frequency range the impedance data evaluated on the basis of simple equivalent electrical circuit model and had been found to follow theoretical prediction. Other parameters such as transport number, distribution coefficient and charge effectiveness were also calculated.

Ishrat, Urfi; Rafiuddin

2013-10-01

56

Alkali Influence on Synthesis of Solid Electrolyte Based on Alkali Nitrate-Alumina  

International Nuclear Information System (INIS)

Research of solid electrolyte based on alumina with addition of alkali materials of barium nitrate, calcium nitrate, sodium nitrate and lithium nitrate has been done. Aluminium hydroxide and alkali nitrate were mixed in mole ratio of 1 : 1 in water media and pyrolyzed at 300oC for 1 hour Pyrolysis result were then mixed with alumina in mole ratio of 1 : 1, compacted and heated at 600oC for 3 hours. To characterize the sample, XRD (X-Ray Diffractometers) and LCR meter (impedance, capacitance, and resistance) were used for analysis the phase and conductivity properties. The result showed formation of alkali-aluminate in which Li-base have the highest room temperature conductivity of 3.1290 x 10-5 S.cm-1, while Ba-base have the lowest conductivity of 5.7266 x 10-8 S.cm-1. (author)

57

Synthesis, rheological behavior and swelling properties of copolymer hydrogels based on poly(N-isopropylacrylamide with hydrophilic monomers  

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Full Text Available In this study, hydrogels of poly(N-isopropylacrylamide-co-acrylamide and poly(N-isopropylacrylamide-co-acrylic acid having a thermoresponsive character were prepared by aqueous free-radical co-polymerization using the ammonium persulfate/N,N,N',N'-tetramethylethylenediamine (APS/TEMED redox-pair initiator system in the presence of N,N'-methylenebisacrylamide (MBAAm crosslinker. (NIPAAm-co-AAm and (NIPAAm-co-AAc hydrogels with different thermoresponsive properties were obtained by fixing the initial NIPAAm/AAm mole ratio and and (NIPAAm-co-AAc mole ratio to 80/20 and changing the crosslinker concentration. The copolymers were characterized with infrared spectroscopy (IR and differential scanning calorimetry (DSC techniques. The swelling response of the copolymers networks as a function of time, temperature and swelling environment has been observed to be dependent on both structural aspects of the polymers and swelling environment. The swelling has been observed to be decrease with increase in MBAAm in the copolypolymers networks. Rheological behavior was studies in oscillatory module. All copolymers have a viscoelastic behaviour. We note that the elastic modulus G' increases with increasing hydrophilic monomers.DOI: http://dx.doi.org/10.4314/bcse.v27i3.14

D. Aliouche

2013-09-01

58

Combustion synthesis-derived tantalum powder for solid-electrolyte capacitors  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the synthesis of capacitor-grade tantalum (Ta) powder via the self-propagating high-temperature synthesis (SHS) method is described. In addition, the sintering aspects and electrical characteristics of the powder are discussed. Ta powder was prepared via the combustion of a Ta{sub 2}O{sub 5}-xMg-kNaCl mixture, under argon pressure. The morphology and size of the final powder particles was controlled by adjusting the Mg-NaCl concentration. The final powder particles had nodular shapes and sizes ranging from 0.1 to 0.5 {mu}m. A leakage current of a sintered Ta sample containing the smallest particle size was 10 {mu}A; its capacitance was 92,738 CV, when a 40-V voltage was applied to the sample.

Won, H.I. [Rapidly Solidified Materials Research Center (RASOM), Chungnam National University, Yuseong, Daejeon 305-764 (Korea, Republic of)], E-mail: rotc4379@hanmail.net; Nersisyan, H.H.; Won, C.W. [Rapidly Solidified Materials Research Center (RASOM), Chungnam National University, Yuseong, Daejeon 305-764 (Korea, Republic of)

2009-06-10

59

Combustion synthesis-derived tantalum powder for solid-electrolyte capacitors  

International Nuclear Information System (INIS)

In this paper, the synthesis of capacitor-grade tantalum (Ta) powder via the self-propagating high-temperature synthesis (SHS) method is described. In addition, the sintering aspects and electrical characteristics of the powder are discussed. Ta powder was prepared via the combustion of a Ta2O5-xMg-kNaCl mixture, under argon pressure. The morphology and size of the final powder particles was controlled by adjusting the Mg-NaCl concentration. The final powder particles had nodular shapes and sizes ranging from 0.1 to 0.5 ?m. A leakage current of a sintered Ta sample containing the smallest particle size was 10 ?A; its capacitance was 92,738 CV, when a 40-V voltage was applied to the sample.

60

Synthesis and characterization of zirconia electrolytes for potential use in energy conversion systems  

Energy Technology Data Exchange (ETDEWEB)

Using a wet-chemical procedure, a series of compositions having between 0 and 22.2 mol % CaO was prepared and subsequently formed into sintered samples having a relative density from 95 to 98%. Sintered samples were prepared of each composition with a geometry appropriate for determining the thermal, electrical or microstructural characteristics. The microstructural aspects of powder synthesis and the development of sintered materials are covered.

Wheat, T.A.

1978-11-15

 
 
 
 
61

Synthesis and proton conductivity studies of doped azole functional polymer electrolyte membranes  

Energy Technology Data Exchange (ETDEWEB)

The development of anhydrous proton-conducting membranes is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 {sup o}C). In this work, poly(vinylbenzylchloride), PVBC was produced by free radical polymerization of 4-vinylbenzylchloride and then it was modified with 5-aminotetrazole (ATET) to obtain poly(vinylbenzylaminotetrazole), PVBC-ATET. The composition of the polymer was verified by elemental analysis (EA) and the structure was characterized by FT-IR and {sup 13}C NMR spectra. According to the elemental analysis result, PVBC was modified by ATET with 80% yield. The polymer was doped with trifluoromethanesulfonic acid (TA) at various molar ratios, x = 1.25, 2.5, 3.75 with respect to tetrazole unit. The proton transfer from TA to the tetrazole rings was proved with FT-IR spectroscopy. Thermogravimetry (TG) analysis showed that the samples are thermally stable up to approximately 200 {sup o}C. Differential scanning calorimetry (DSC) results illustrated the homogeneity of the materials. Cyclic voltammetry (CV) study illustrated that the electrochemical stability domain for PVBC-ATET-TA{sub 2.5} extends over 3.0 V. The proton conductivity of these materials increased with dopant concentration and the temperature. Maximum proton conductivity of PVBC-ATET-TA{sub 2.5} was found to be 0.01 S/cm at 150 {sup o}C in the anhydrous state.

Ozden, Sehmus [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey); Celik, Sevim Unueguer, E-mail: sunugur@fatih.edu.t [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey); Bozkurt, Ayhan [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey)

2010-12-01

62

Synthesis and proton conductivity studies of doped azole functional polymer electrolyte membranes  

International Nuclear Information System (INIS)

The development of anhydrous proton-conducting membranes is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 oC). In this work, poly(vinylbenzylchloride), PVBC was produced by free radical polymerization of 4-vinylbenzylchloride and then it was modified with 5-aminotetrazole (ATET) to obtain poly(vinylbenzylaminotetrazole), PVBC-ATET. The composition of the polymer was verified by elemental analysis (EA) and the structure was characterized by FT-IR and 13C NMR spectra. According to the elemental analysis result, PVBC was modified by ATET with 80% yield. The polymer was doped with trifluoromethanesulfonic acid (TA) at various molar ratios, x = 1.25, 2.5, 3.75 with respect to tetrazole unit. The proton transfer from TA to the tetrazole rings was proved with FT-IR spectroscopy. Thermogravimetry (TG) analysis showed that the samples are thermally stable up to approximately 200 oC. Differential scanning calorimetry (DSC) results illustrated the homogeneity of the materials. Cyclic voltammetry (CV) study illustrated that the electrochemical stability domain for PVBC-ATET-TA2.5 extends over 3.0 V. The proton conductivity of these materials increased with dopant concentration and the temperature. Maximum proton conductivity of PVBC-ATET-TA2.5 was found to be 0.01 S/cm at 150 oC in the anhydrous state.

63

Synthesis of zinc oxide porous structures by anodization with water as an electrolyte  

Science.gov (United States)

We report a simple, reliable and one-step method of synthesizing ZnO porous structures at room temperature by anodization of zinc (Zn) sheet with water as an electrolyte and graphite as a counter electrode. We observed that the de-ionized (DI) water used in the experiment is slightly acidic (pH=5.8), which is due to the dissolution of carbon dioxide from the atmosphere forming carbonic acid. Porous ZnO is characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and photoluminescence (PL) studies. The current-transient measurement is carried out using a Gamry Instruments Reference 3000 and the thickness of the deposited films is measured using a Dektak surface profilometer. The PL, Raman and X-ray photoelectron spectroscopy are used to confirm the presence of ZnO phase. We have demonstrated that the hybrid structures of ZnO and poly (3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) exhibit good rectifying characteristics. The evaluated barrier height and the ideality factor are 0.45 eV and 3.6, respectively.

Shetty, Amitha; Nanda, Karuna Kar

2012-10-01

64

Synthesis, spectroscopic and electrochemical performance of pasted ?-nickel hydroxide electrode in alkaline electrolyte.  

Science.gov (United States)

?-Nickel hydroxide (?-Ni(OH)2) was successfully synthesized using precipitation method. The structure and property of the ?-Ni(OH)2 were characterized by X-ray diffraction (XRD), Fourier Transform infra-red (FT-IR), Raman spectra and thermal gravimetric-differential thermal analysis (TG-DTA). The results of the FTIR spectroscopy and TG-DTA studies indicate that the ?-Ni(OH)2 contains water molecules and anions. The microstructural and composition studies have been performed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. A pasted-type electrode is prepared using ?-Ni(OH)2 powder as the active material on a nickel sheet as a current collector. Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) studies were performed to evaluate the electrochemical performance of the ?-Ni(OH)2 electrode in 6M KOH electrolyte. CV curves showed a pair of strong redox peaks as a result of the Faradaic redox reactions of ?-Ni(OH)2. The proton diffusion coefficient (D) for the present ?-Ni(OH)2 electrode material is found to be 1.44×10(-12) cm(2) s(-1). Further, electrochemical impedance studies confirmed that the ?-Ni(OH)2 electrode reaction processes are diffusion controlled. PMID:25128682

Shruthi, B; Bheema Raju, V; Madhu, B J

2015-01-25

65

Synthesis, processing and characterization of calcia-stabilized zirconia solid electrolytes for oxygen sensing applications  

International Nuclear Information System (INIS)

Precursor powders of calcia-stabilized zirconia (CSZ) solid electrolytes have been synthesized by a sol-gel method. The phase evolution of the precursor powders after thermal treatments at different temperatures were analysized by X-ray diffraction technique. Disc-shaped sensor elements were fabricated via uniaxial pressing of the calcined powders and subsequently sintered at 1650 deg. C. Scanning electron microscopy (SEM) was used to analyze the microstructure of the sintered pellets. Platinum electrodes were applied to the sintered elements to produce potentiometric/electrochemical gas sensors. The electrical response of the gas sensors to oxygen and the complex impedance of the sensors in air were measured at various temperatures. Impedance analyses indicate that the sensor cell with 15 mol% CaO has much lower resistance (the sum of bulk and grain-boundary resistance) than the sensor cell with 22 mol% CaO. This is also reflected by the EMF responses of both sensor cells to various oxygen concentrations in the testing gas. The EMF deviation from the theoretical value of the CSZ sensor cell with 22 mol% CaO was larger than that of the CSZ sensor cell with 15 mol% CaO. The corrrelations between material compositions, microstructures of the sintered pellets and the electrical properties of the sensors are discussed

66

Self-propagating high-temperature synthesis of La(Sr)Ga(Mg)O3-? for electrolyte of solid oxide fuel cells  

International Nuclear Information System (INIS)

This paper describes self-propagating high-temperature synthesis (SHS) of an electrolyte for solid oxide fuel (SOFC), in comparison to a conventional solid-state reaction method (SRM). Doped-lanthanum gallate: La0.9Sr0.1Ga0.8Mg0.2O3-? (LSGM9182) and LSGM9173 as the SOFC electrolyte, was prepared by the SHS and sintered at different temperatures, for measuring the electrical conductivity of the sintered LSGM and the power generating performance at 1073 K, in comparison to the SRM. In the SHS, the LSGM powders with smaller size were obtained and easily sintered at the 100 K-lower temperature, 1673 K, than in the SRM. Most significantly, the electrical conductivity of the sintered LSGM9182 was as high as 0.11 S cm-1 and its maximum power density was a value of 245 mW cm-2 in the cell configuration of Ni/LSGM9182 (0.501 mm in thickness)/Sm0.5Sr0.5CoO3. The conclusion was that the proposed SHS-sintering method with many benefits of minimizing the energy requirement and the processing time in the production, easing temperature restriction for the sintering, and improving the electrolyte performance up to a conventional level is practicable for producing the LSGM-electrolyte of SOFC at an intermediate-temperature application

67

Simultaneous generation of synthesis gas and electric power by internal reforming fuel cells utilizing LaGaO{sub 3} based electrolytes  

Energy Technology Data Exchange (ETDEWEB)

A novel solid oxide fuel cell (SOFC) utilizing partial oxidation of methane (CH{sub 4}+1/2O{sub 2}=CO+2H{sub 2}) as internal reforming reaction was investigated in the present study. Large electric power as well as CO-H{sub 2} mixture with molar ratio of 2 were obtained by applying LaGaO{sub 3} perovskite as electrolyte. Although the open circuit potential decreased, the maximum power density increased by doping a small amount of Co to the LaGaO{sub 3} electrolyte. In particular, the increase in the power density at 1073K was significant. Increasing the amount of doped Co monotonically enhanced the hole conduction resulting in a decrease in the open circuit potential and an increase on the amount of leaked oxygen which results in diminished electric power. Consequently, it became clear that the optimized composition for this electrolyte was La{sub 0.9}Sr{sub 0.1}Ga{sub 0.115}Co{sub 0.085}O{sub 3} considering the power density and the amount of oxygen leakage. Although the thickness of electrolyte with the above composition was as thick as 0.5 mm, a maximum power density and yield of synthesis gas were obtained at 242 mW/cm{sup 2} and 16%, respectively

Yamada, Takashi; Hiei, Yoshiko; Akbay, Taner; Ishihara, Tatsumi; Takita, Yusaku [Department of Applied Chemistry, Faculty of Engineering, Oita University, Dannoharu 700, Oita 870-11 (Japan)

1998-12-01

68

Synthesis, physical and electrical characterization of polymer electrolytes and polymer complexes containing polyhalides  

Energy Technology Data Exchange (ETDEWEB)

The conductivity and dielectric response was determined for poly (propylene oxide) (PPO), the polymeric solid electrolytes (PPO)[sub 8]NH[sub 4]SO[sub 3]CF[sub 3], (PPO)[sub 16]NaI, (PPO)[sub 10]NaI and (PPO)[sub 8]NaI and the sodium polyiodide complex, (PPO)[sub 8]NaI[sub 9], in the frequency range from dc to 6 GHz and the temperature range from 173-323 K at 3 GHz. These data were used to make the first comparisons between an amorphous host polymer and its salt complexes. The addition of salt to PPO results in a considerable change in dielectric properties. The dielectric loss spectrum of PPO displays a broad [beta]-relaxation attributed to the micro-Brownian motion of the polymer while no appreciable relaxation peak is observed for (PPO)[sub 8]NH[sub 4]SO[sub 3]CF[sub 3]. The conductivity of the previously characterized (PEO)[sub 8]NH[sub 4]SO[sub 3]CF[sub 3] is higher than (PPO)[sub 8]NH[sub 4]SO[sub 3]CF[sub 3] over the entire frequency range covered. The methyl group on PPO apparently sterically restricts the local motions of the polymer necessary for ion conduction. The dielectric loss spectrum of (PPO)[sub 8]NaI displays a narrow relaxation peak around 10 MHz, possibly associated with the motions of NaI aggregates. (PPO)[sub 8]NaI[sub 9] displays a much higher conductivity than simple polymer-salt complexes. The lack of frequency dependence of the (PPO)[sub 8]NaI[sub 9] conductivity compared to that of the simple polymer-salt complexes suggests that long range charge transport in (PPO)[sub 8]NaI[sub 9] is dominated by a process that is much faster than the diffusion of ions in the polymer solvent. Resonance Raman spectra reveal the presence of a rich variety of polyhalide species in the products resulting from the addition of Br[sub 2], IBr or I[sub 2] to PPO-LiBr or PPO-LiI salt complexes. Impedance measurements demonstrate high bulk conductivities. There appears to be little correlation between conductivity and iodine or bromine content.

Tipton, A.L.

1992-01-01

69

Synthesis of Solid Electrolyte Based on Lithium Glass (Ag2S)x(LiPO3)1-x  

International Nuclear Information System (INIS)

Synthesis of solid electrolyte based on lithium glass (Ag2S)x(LiPO3)1-x has been developed. Melt quenching method was used to synthesize the superionic conducting glasses (Ag2S)x(LiPO3)1-x with x 0; 0.3; and 0.5 by using LiPO3 and Ag2S. X-ray diffraction showed that LiPO3 (x =0, LSX 00) (Ag2S)0.3(LiPO3)0.7, (LSX 03) and (Ag2S)0.5(LiPO3)0.5 (LSX 05) have amorphous structure. Thermal data measured by DSC showed that the glass transition temperature decreases from 149 oC for x = 0 (LSX 00) to 147 oC for x = 0.5 (LSX 05). SEM photo of LiPO3 showed smooth surface without grain, while for (Ag2S)0.3(LiPO3)0.7-C (LSX 03 C) and (Ag2S)0.5-C(LiPO3)0.5-C(LSX 05 C), the Ag2S grain that dissolved in LiPO3 matrix is shown. Increasing of Ag2S in LiPO3 glass consistently increased the conductivity of (Ag2S)x(LiPO3)1-x superionic. The milling of Ag2S could also increase the conductivity of (Ag2S)x(LiPO3)1-x superionic, in which the conductivity of (Ag2S)0.5(LiPO3)0.5 superionic increased from 2.5 x 10-3 S/cm to 1.143 S/cm. (author)

70

Synthesis and characterization of polymer electrolyte membranes with controlled ion transport properties  

Science.gov (United States)

Ion-containing block copolymers hold promise as next-generation polymer electrolyte membrane (PEM) materials due to their capability to self-assemble into ordered nanostructures facilitating proton transport over a wide range of conditions. Ion-containing block copolymers, sulfonated poly(styrene- b-vinylidene fluoride-b-styrene), with varied degrees of sulfonation were synthesized. The synthetic strategy involved a new approach to chain-end functionalized poly(vinylidene fluoride) as a macro-initiator followed by atom transfer polymerization of styrene and sulfonation. Characterization of the polymers were extensively carried out by 1H and 19F nuclear magnetic resonance and Fouriertransform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry analysis. Tapping mode atomic force microscopy and transmission electron microscopy were applied to study the phase separation and self-assembled morphology. Strong dependence of ion exchange capacity, water absorption, morphology and proton conductivity on the degree of sulfonation has been found. It has been observed that the conductivities of the block copolymers are considerably higher than the random copolymers of polystyrene and sulfonated polystyrene possessing similar ion exchange capacities. Copolymers of vinylidene fluoride and perfluoro(4-methyl-3,6-dioxane-7-ene) sulfonyl fluoride containing amino end-groups were synthesized for the first time. The prepared aminoterminated polymers underwent cross-linking reactions with 1,3,5-benzene triisocyanate to form proton conductive networks. The chain-end crosslinked fluoropolymer membranes exhibited excellent thermal, hydrolytic and oxidative stabilities. The ion exchange capacity, water uptake, the state of absorbed water, and transport properties of the membranes were found to be highly dependent upon the chemical composition of the copolymers. The cross-linked membranes showed extremely low methanol permeability, while maintaining high proton conductivity at the same order of magnitude as Nafion. This unique transport feature gave rise to exceedingly higher electrochemical selectivity in relation to Nafion. The selectivity characteristics have been rationalized based on the formation of restrained ionic domains and the state of the absorbed water within the membranes. A series of new Nafion-based composite membranes were prepared via an in situ sol-gel reaction of 3-(trihydroxylsilyl) propane-1-sulfonic acid and solution casting method. The morphological structure, ion-exchange capacity, water uptake, proton conductivity, and methanol permeability of the resulting composite membranes were extensively investigated as functions of the content of sulfopropylated polysilsesquioxane filler, temperature, and relative humidity. Unlike the conventional Nafion/silica composites, the prepared membranes exhibit an increased water uptake and associated enhancement in proton conductivity compared to unmodified Nafion. In particular, considerably high proton conductivities at 80 and 120 °C under 30% relative humidity were demonstrated in the composite membranes, which are over 2 times greater than that of Nafion. In addition to a remarkable improvement in proton conductivity, the composite membranes displayed lower methanol permeability and superior electrochemical selectivity in comparison to the pure Nafion membrane. A versatile and facile synthetic approach was developed for the preparation of a family of new ionomers with rigid aromatic backbones and pendant perfluorinated sulfonic acid groups. Variation in the chemical composition and structure of the new aromatic ionomers were performed to optimize PEM properties and fuel cell performance. The ionomers prepared from condensation polymerization of Sodium 1,1,2,2-tetrafluoro-2-(2',3',5',6'-tetrafluoro-phenoxy)- ethane sulfonate and bisphenol monomers, e.g. hydroquinone, 4,4'-biphenol, or their mixture with appropriate ratio, exhibited comparable or greater proton conductivity in relation to Nafion. New aromatic ionomers also showed other outstanding PEM prop

Xu, Kui

71

Synthesis and electrochemical characterization of hybrid membrane Nafion-SiO2 for application as polymer electrolyte in PEM fuel cell  

International Nuclear Information System (INIS)

In this work, the effect of sol-gel synthesis parameters on the preparation and polarization response of Nafion-SiO2 hybrids as electrolytes for proton exchange membrane fuel cells (PEMFC) operating at high temperatures (130 degree C) was evaluated. The inorganic phase was incorporated in a Nafion matrix with the following purposes: to improve the Nafion water uptake at high temperatures (> 100 degree C); to increase the mechanical strength of Nafion and; to accelerate the electrode reactions. The hybrids were prepared by an in-situ incorporation of silica into commercial Nafion membranes using an acid-catalyzed sol-gel route. The effects of synthesis parameters, such as catalyst concentration, sol-gel solvent, temperature and time of both hydrolysis and condensation reactions, and silicon precursor concentration (Tetraethyl orthosilicate - TEOS), were evaluated as a function on the incorporation degree and polarization response. Nafion-SiO2 hybrids were characterized by gravimetry, thermogravimetric analysis (TGA), scanning electron microscopy and X-ray dispersive energy (SEM-EDS), electrochemical impedance spectroscopy (EIS), and X-ray small angle scattering (SAXS). The hybrids were tested as electrolyte in single H2/O2 fuel cells in the temperature range of 80 - 130 degree C and at 130 degree C and reduced relative humidity (75% and 50%). Summarily, the hybrid performance showed to be strongly dependent on the synthesis parameters, mainly, the type of alcohol and the TEOS concentration. (author)

72

Synthesis and properties of a cation-conducting, high temperature polymer electrolyte. Interim technical report, March 1992-April 1993  

Energy Technology Data Exchange (ETDEWEB)

A new class of polymer electrolyte, high temperature polymer electrolytes, as an electrolyte in high discharge rate batteries is proposed. As an initial effort in the development of these materials, sodium and lithium salts of sulfonated poly(p-phenyleneterephtalamide) have been prepared. DSC and electrical conductivity studies have been performed on these films. The conductivity exhibits Arrhenius behavior over the temperature range in which they are thermally stable (1 80-240 deg C) with the material containing sodium being more conductive than those containing lithium. Although the electrical performance of these materials is inadequate from a practical standpoint, it is suggested that with additional development these materials could function as electrolytes for high discharge rate batteries.... High temperature polymer electrolyte, Sulfonated polyaromide, Lithium conductor, Sodium conductor.

Okamoto, Y.; Xu, Z.S.; McLin, M.G.; Fontanella, J.J.; Pak, Y.S.

1993-04-16

73

Polymer Electrolytes  

Science.gov (United States)

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

Hallinan, Daniel T.; Balsara, Nitash P.

2013-07-01

74

Rheological characteristics of synthetic road binders  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with the synthesis of polymer binders from monomers that could in future be derived from renewable resources. These binders consist of polyethyl acrylate (PEA) of different molecular weight, polymethyl acrylate (PMA) and polybutyl acrylate (PBA), which were synthesised from ethyl acrylate, methyl acrylate and butyl acrylate, respectively, by atom transfer radical polymerization (ATRP). The fundamental rheological properties of these binders were determined by means of a dynamic shear rheometer (DSR) using a combination of temperature and frequency sweeps. The results indicate that PEA has rheological properties similar to that of 100/150 penetration grade bitumen, PMA similar rheological properties to that of 10/20 penetration grade bitumen, while PBA, due to its highly viscous nature and low complex modulus, cannot be used on its own as an asphalt binder. The synthetic binders were also combined with conventional penetration grade bitumen to produce a range of bitumen-synthetic polymer binder blends. These blends were batched by mass in the ratio of 1:1 or 3:1 and subjected to the same DSR rheological testing as the synthetic binders. The blends consisting of a softer bitumen (70/100 pen or 100/150 pen) with a hard synthetic binder (PMA) tended to be more compatible and therefore stable and produced rheological properties that combined the properties of the two components. The synthetic binders and particularly the extended bitumen samples (blends) produced rheological properties that showed similar characteristics to elastomeric SBS PMBs. 30 refs., 12 figs., 2 tabs.

Gordon D. Airey; Musarrat H. Mohammed; Caroline Fichter [University of Nottingham, Nottingham (United Kingdom)

2008-08-15

75

Synthesis of calcium-deficient by hydroxyapatite-collage composite by the electrolytic deposition method; Denkai sekishutsu ho ni yoru karushiumu kesson hidorokishiapataito-coragen fukugotai no gosei  

Energy Technology Data Exchange (ETDEWEB)

Hydroxyapatite is known as that it has a good joining property with teeth and bone, and a study on the application to the living body was conducted by using this property. Its application examples were given as the cement used in dentistry, the artificial tooth root, the artificial bone, the bone cement and the artificial joint. However, they were a sinter heated at more than 1000degC, and were put into use by means of reinforcement using a titanium alloy since their mechanical strength was low. In this study, synthesis of calcium-deficient hydroxyapatite (DAp) and collagen composite by the electrolytic deposition method was attempted in order to develop bionic materials, and the correlation of various physical properties of the obtained composite and the electrolytic deposition conditions were investigated. When the electrolytic voltage is more than 22.0V, a single phase of DAp could be obtained. It was clarified that a DAp and collagen composite was synthesized from results of IR and ESR. 16 refs., 5 figs.

Okamura, H. [Niigata University, Niigata (Japan). Graduate School Of Science and Technology; Yasuda, M.; Oota, M. [Niigata University, Niigata (Japan)

1997-07-05

76

Synthesis of single-phase HgBa2Ca2Cu3O8+dgr high-Tc superconducting films using the multistep electrolytic process  

Science.gov (United States)

We report on the use of the multistep electrolytic process for the synthesis of high-Tc single-phase HgBa2Ca2Cu3O8+dgr (Hg-1223) superconducting films. The process includes: (i) deposition of BaCaCu precursor alloy; (ii) oxidation of BaCaCu films; (iii) electrolytic intercalation of Hg in precursor Ba2Ca2Cu3Ox films; (iv) electrochemical oxidation and annealing of Hg-intercalated Ba2Ca2Cu3Ox films to convert into Hg-1223. Films were characterized by thermo-gravimetric analysis and differential thermal analysis, x-ray diffraction and scanning electron microscopy. The electrolytic intercalation of Hg in Ba2Ca2Cu3Ox precursor proves to be a novel alternative to the high-temperature-high-pressure mercuration process. The films are single-phase Hg-1223 with Tc = 121.5 K and Jc = 4.3 × 104 A cm-2 at 77 K.

Shivagan, D. D.; Shirage, P. M.; Ekal, L. A.; Pawar, S. H.

2004-01-01

77

Synthesis by sol–gel route of oxyapatite powders for dense ceramics : applications as electrolytes for solid oxide fuel cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Solid oxide fuel cells have considerable interest in recent years, because of their high efficiency and environmentally friendly nature. Such systems required oxygen-conducting electrolytes and now the most common electrolyte is yttria stabilized zirconia (YSZ). This compound exhibits high oxide ion conductivity at elevated temperatures (850–1000 °C). However, this high working temperature causes problems in terms of materials selection and lifetime. One solution is to develop new oxide...

Ce?le?rier, Ste?phane; Laberty-robert, Christel; Ansart, Florence; Calmet, Christophe; Stevens, Philippe

2005-01-01

78

Self-propagating high-temperature synthesis of La(Sr)Ga(Mg)O{sub 3-{delta}} for electrolyte of solid oxide fuel cells  

Energy Technology Data Exchange (ETDEWEB)

This paper describes self-propagating high-temperature synthesis (SHS) of an electrolyte for solid oxide fuel (SOFC), in comparison to a conventional solid-state reaction method (SRM). Doped-lanthanum gallate: La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM9182) and LSGM9173 as the SOFC electrolyte, was prepared by the SHS and sintered at different temperatures, for measuring the electrical conductivity of the sintered LSGM and the power generating performance at 1073 K, in comparison to the SRM. In the SHS, the LSGM powders with smaller size were obtained and easily sintered at the 100 K-lower temperature, 1673 K, than in the SRM. Most significantly, the electrical conductivity of the sintered LSGM9182 was as high as 0.11 S cm{sup -1} and its maximum power density was a value of 245 mW cm{sup -2} in the cell configuration of Ni/LSGM9182 (0.501 mm in thickness)/Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}. The conclusion was that the proposed SHS-sintering method with many benefits of minimizing the energy requirement and the processing time in the production, easing temperature restriction for the sintering, and improving the electrolyte performance up to a conventional level is practicable for producing the LSGM-electrolyte of SOFC at an intermediate-temperature application.

Ishikawa, Hiroyuki [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Sapporo 060-8628 (Japan); Enoki, Makiko [Department of Applied Chemistry, Faculty of Engineering, Kyusyu University, Fukuoka 812-8581 (Japan); Ishihara, Tatsumi [Department of Applied Chemistry, Faculty of Engineering, Kyusyu University, Fukuoka 812-8581 (Japan); Akiyama, Tomohiro [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Sapporo 060-8628 (Japan)]. E-mail: takiyama@eng.hokudai.ac.jp

2007-03-14

79

Synthesis and electrical properties of scheelite Ca1-xSmxMoO4+? solid electrolyte ceramics  

International Nuclear Information System (INIS)

Graphical abstract: Scheelite-type Ca1-xSmxMoO4+? electrolyte ceramics can be considered as one of the best candidates to replace the YSZ electrolyte materials for SOFCs because of their high oxide ion conduction. Research highlights: ? SmxCa1-xMoO4+? solid electrolyte with a tetragonal scheelite structure. ? SmxCa1-xMoO4+? electrolyte is one of the best candidates to replace the YSZ electrolyte for SOFCs because of their high oxide ion conduction. ? The sintering temperature is greatly lower than traditional YSZ electrolyte. -- Abstract: Scheelite-type Ca1-xSmxMoO4+? electrolyte powders were prepared by the sol-gel auto-combustion process. The crystal structure of the samples was determined by employing the techniques of X-ray diffraction (XRD). According to the XRD analysis, the formed continuous series of Ca1-xSmxMoO4+? (0 ? x ? 0.3) solid solutions had the structure of tetragonal scheelite, and the lattice parameters increased with increasing x in the Sm-substituted system. Results of sinterability and electrochemical testing revealed that the performances of Sm-doped calcium molybdate were superior to that of pure CaMoO4. Ca1-xSmxMoO4+? ceramics show higher sinterability, and the Ca0.8Sm0.2MoO4+? sample with 98.7% of the theoretical density were obtained after being sintered at 1250 oC for 4 h. The conductivity increased with increasing samarium content, and a total conductivity 9.54 x 10-3 S cm-1 at 800 oC could be obtained in Ca0.8Sm0.2MoO4+? sintered at 1250 oC for 4 h.

80

Electrolytes - urine  

Science.gov (United States)

The electrolytes - urine test measures specific chemicals called electrolytes in urine. It usually measures the levels of calcium, chloride, potassium, or sodium. See also: Calcium - urine Chloride - urine Potassium - urine ...

 
 
 
 
81

Synthesis of graphene nanosheets by the electrolytic exfoliation of graphite and their direct assembly for lithium ion battery anodes  

International Nuclear Information System (INIS)

Graphene nanosheets were produced through electrolytic exfoliation of graphite foils in an aqueous solution containing an electrolyte, poly(sodium-4-styrenesulfonate). We confirmed the formation of graphene nanosheets by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy. The electrochemical performance of the graphene nanosheets was evaluated using cyclic voltammetry, galvanostatic charge–discharge cycling, and electrochemical impedance spectroscopy. In order to address the feasibility of their use as lightweight anodes for a Li ion battery, we also present the direct assembly of graphene nanosheets onto metal current collectors and the fabrication of freestanding graphene nanosheets paper electrodes. Highlights: ? Graphene nanosheets were electrolytically synthesized from graphite foils. ? The direct electrophoretic deposition of the graphenes onto current collectors is described. ? Promising Li storage capabilities of graphene anode were found.

82

Synthesis of graphene nanosheets by the electrolytic exfoliation of graphite and their direct assembly for lithium ion battery anodes  

Energy Technology Data Exchange (ETDEWEB)

Graphene nanosheets were produced through electrolytic exfoliation of graphite foils in an aqueous solution containing an electrolyte, poly(sodium-4-styrenesulfonate). We confirmed the formation of graphene nanosheets by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy. The electrochemical performance of the graphene nanosheets was evaluated using cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. In order to address the feasibility of their use as lightweight anodes for a Li ion battery, we also present the direct assembly of graphene nanosheets onto metal current collectors and the fabrication of freestanding graphene nanosheets paper electrodes. Highlights: Black-Right-Pointing-Pointer Graphene nanosheets were electrolytically synthesized from graphite foils. Black-Right-Pointing-Pointer The direct electrophoretic deposition of the graphenes onto current collectors is described. Black-Right-Pointing-Pointer Promising Li storage capabilities of graphene anode were found.

Lee, Seung-Hun; Seo, Seung-Deok; Park, Kyung-Soo; Shim, Hyun-Woo [Department of Materials Science and Engineering, Ajou University, San 5, Woncheon-dong, Yeongtong-gu, Suwon 443-749 (Korea, Republic of); Kim, Dong-Wan, E-mail: dwkim@ajou.ac.kr [Department of Materials Science and Engineering, Ajou University, San 5, Woncheon-dong, Yeongtong-gu, Suwon 443-749 (Korea, Republic of)

2012-08-15

83

Rheology and deep tectonics  

Directory of Open Access Journals (Sweden)

Full Text Available The distribution of the rheological properties of the lithosphere in space, and their variations in time, have a profound effect on the resulting tectonic deformation. A classical way of estimating these properties makes use of rheological profiles (strength envelopes. Although rheological profiles are based on assumptions and approximations which limit their resolving power, they are an efficient first-order tool for the study of lithosphere rheology, and their application clarifies the dynamics of tectonic processes. Two examples of the interaction of rheology and tectonics are discussed, namely, the post-orogenic relaxation of Moho topography (which is an additional factor to be considered in tectonic inversion, and the strength control on the level of necking in extension (which may lead to apparent local isostasy at passive continental margins and in sedimentary basins.

G. Ranalli

1997-06-01

84

Development of a model colloidal system for rheology simulation.  

Energy Technology Data Exchange (ETDEWEB)

The objective of the experimental effort is to provide a model particle system that will enable modeling of the macroscopic rheology from the interfacial and environmental structure of the particles and solvent or melt as functions of applied shear and volume fraction of the solid particles. This chapter describes the choice of the model particle system, methods for synthesis and characterization, and results from characterization of colloidal dispersion, particle film formation, and the shear and oscillatory rheology in the system. Surface characterization of the grafted PDMS interface, dispersion characterization of the colloids, and rheological characterization of the dispersions as a function of volume fraction were conducted.

Schunk, Peter Randall; Tallant, David Robert; Piech, Martin (United Technologies Research Center, East Hartford, CT); Bell, Nelson Simmons; Frischknecht, Amalie Lucile

2008-10-01

85

Development and synthesis of materials for poly electrolyte membranes with ionic liquids for application in Lithium-ion batteries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Within the field of energy storage and charge transfer, the lithium polymer batteries are one of the leading technologies, due to their low manufacture cost and their possible variety of packaging shapes. Despite their good thermal stability and very good weight to energy ratio, lithium ion batteries use as a electrolyte system a mixture of ethylene carbonate and diethyl carbonate as solvent which have a high risk of deflagration when they come in contact with water. Thus the developement...

Grothe, Dorian C.

2012-01-01

86

Synthesis and characterization of a new hyperbranched organic-inorganic solid polymer electrolyte with cyanuric chloride as a core element  

Energy Technology Data Exchange (ETDEWEB)

Highlights: > The electrolyte exhibits an ionic conductivity value of 4.4 x 10{sup -5} S cm{sup -1} at 30 deg. C. > Solid-state NMR confirms the hybrid structure of hybrid electrolytes. > Li line width reveals that the mobility of Li ion is coupled with the polymer motion. > PGSE NMR indicates that polymer segmental mobility affects Li diffusion. - Abstract: A new hyperbranched organic-inorganic hybrid electrolyte based on the use of 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride, CC) as the coupling core to couple with oligo(oxyalkylene)-amines, followed by condensation with (3-glycidoxypropyl)-trimethoxysilane (GLYMO) and complexed with LiClO{sub 4}, has been prepared and characterized. The Vogel-Tamman-Fulcher (VTF) like conductivity behavior is observed in the present organic-inorganic hybrid electrolytes with a maximum ionic conductivity value of 4.4 x 10{sup -5} S cm{sup -1} at 30 deg. C. Multinuclear NMR techniques are used to provide a microscopic view for the specific interaction between the polymer chains and Li{sup +} cations and their dynamic behaviors. The results of 2D {sup 1}H-{sup 13}C wide-line separation (WISE) and {sup 7}Li static line NMR width measurements divulge that the mobility of the {sup 7}Li cations is strongly related to a dynamic environment created by the polymer motion in the amorphous phase. The combined results of conductivity and {sup 7}Li pulse-gradient spin-echo (PGSE) NMR self-diffusion coefficient measurements reveal that the conductivity enhancement at low salt concentrations is mainly caused by the high mobility of the lithium cations.

Pan, Yu-Chi; Saikia, Diganta [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China); Fang, Jason; Tsai, Li-Duan [Department of Fuel Cell Materials and Advanced Capacitors, Division of Energy Storage Materials and Technology, Material and Chemical Laboratories, Industrial Technology Research Institute, Hsin-Chu 300, Taiwan (China); Fey, George T.K. [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054, Taiwan (China); Kao, Hsien-Ming, E-mail: hmkao@cc.ncu.edu.t [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China)

2011-10-01

87

Synthesis and characterization of a new hyperbranched organic-inorganic solid polymer electrolyte with cyanuric chloride as a core element  

International Nuclear Information System (INIS)

Highlights: ? The electrolyte exhibits an ionic conductivity value of 4.4 x 10-5 S cm-1 at 30 deg. C. ? Solid-state NMR confirms the hybrid structure of hybrid electrolytes. ? Li line width reveals that the mobility of Li ion is coupled with the polymer motion. ? PGSE NMR indicates that polymer segmental mobility affects Li diffusion. - Abstract: A new hyperbranched organic-inorganic hybrid electrolyte based on the use of 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride, CC) as the coupling core to couple with oligo(oxyalkylene)-amines, followed by condensation with (3-glycidoxypropyl)-trimethoxysilane (GLYMO) and complexed with LiClO4, has been prepared and characterized. The Vogel-Tamman-Fulcher (VTF) like conductivity behavior is observed in the present organic-inorganic hybrid electrolytes with a maximum ionic conductivity value of 4.4 x 10-5 S cm-1 at 30 deg. C. Multinuclear NMR techniques are used to provide a microscopic view for the specific interaction between the polymer chains and Li+ cations and their dynamic behaviors. The results of 2D 1H-13C wide-line separation (WISE) and 7Li static line NMR width measurements divulge that the mobility of the 7Li cations is strongly related to a dynamic environment created by the polymer motion in the amorphous phase. The combined results of conductivity and 7Li pulse-gradient spin-echo (PGSE) NMR self-diffusion coefficient measurements reveal that the conductivity enhancement at low salt concentrations is mainly caused by the high mobility of the lithium cations.

88

Synthesis and studies of boron based anion receptors and their use in non-aqueous electrolytes for lithium batteries  

Energy Technology Data Exchange (ETDEWEB)

A new family of anion receptors based on boron compounds has been synthesized. These compounds can be used as anion receptors in lithium battery electrolytes and can greatly increase solubility and ionic conductivities of various lithium salts, such as LiF, LiCl, CF{sub 3}COOLi and C{sub 2}F{sub 5}COOLi, in DME solutions. Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy studies show that Cl{sup {minus}} anions of LiCl are complexed with these compounds in DME solutions. The electrochemical stability of lithium salts and one of the boron compounds in deferent solvents was studied. For the first time, LiF has been successfully used as conducting salt in a novel electrolyte with this boron compound as an additive in DME. A rechargeable Li/LiMn{sub 2}O{sub 4} cell using this electrolyte was successfully cycled 51 times. However, the capacity fades with cycling due to decomposition of the solvent. The cycling performance of the battery was greatly improved by replacing DME with PC-EC-DMC as the solvent.

Sun, X.; Yang, X.Q.; Lee, H.S.; McBreen, J. [Brookhaven National Lab., Upton, NY (United States); Choi, L.S. [Naval Research Lab., Washington, DC (United States)

1998-12-31

89

Rheological phenomena in focus  

CERN Document Server

More than possibly any other scientific discipline, rheology is easily visualized and the relevant literature contains many excellent photographs of unusual and often bizarre phenomena. The present book brings together these photographs for the first time. They are supported by a full explanatory text. Rheological Phenomena in Focus will be an indispensable support manual to all those who teach rheology or have to convince colleagues of the practical relevance of the subject within an industrial setting. For those who teach fluid mechanics, the book clearly illustrates the difference be

Boger, DV

1993-01-01

90

Rheology of waxy oils  

Energy Technology Data Exchange (ETDEWEB)

It is well known that below the crystallization temperature the rheology of waxy oils changes from Newtonian to an extremely complex non-Newtonian behavior, which is shear-rate and temperature-history dependent. Along the last decades a lot of effort has been put into obtaining reliable rheological measurements from different oils so as to understand the yielding of waxy oils as well as the effects of shear and temperature histories on rheological properties, such as viscosity, yield stress, storage and loss moduli. In this paper we examine in detail the related literature, discussing the main reasons for some disagreements concerning the history effects on the flow properties of waxy oils. In addition, we performed temperature ramps and stress-amplitude-sweep tests and compared the results obtained with the main trends observed, highlighting the effects of cooling and shear on the microstructure and consequently on the rheological properties of these oils. (author)

Alicke, Alexandra A.; Marchesini, Flavio H.; Mendes, Paulo R. de Souza [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)], e-mails: fhmo@puc-rio.br, pmendes@puc-rio.br; Ziglio, Claudio [Petrobras Research Center, Rio de Janeiro, RJ (Brazil)], e-mail: ziglio@petrobras.com.br

2010-07-01

91

Propriedades reológicas e microestruturais de eletrólito de ZrO2/Y2O3 / Microstructural and rheological properties of ZrO2/Y2O3 electrolyte  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Para reduzir a temperatura de operação das pilhas a combustível de óxido sólido (PaCOS), estruturas com filmes finos de eletrólito depositados, por aerografia, sobre suportes de anodo porosos foram desenvolvidas. As barbotinas, empregadas para fabricação dos filmes, foram preparadas a partir de susp [...] ensões com pós de zircônia estabilizada com ítria (ZEI), solventes, dispersantes, ligantes e plastificantes apropriados. Neste trabalho, foi feito o estudo da influência dos ligantes sobre a estabilidade das suspensões e as propriedades microestruturais dos filmes de ZEI. Três barbotinas foram elaboradas com composições diferentes de ligantes (0,5; 1,0 e 2,0 % p/p). Todas apresentaram comportamento de fluidos pseudoplásticos e tixotrópicos, de acordo com medidas de viscosidade e taxa de cisalhamento. Os filmes foram sinterizados a 1500 ºC/6h. As micrografias eletrônicas de varredura (MEV) foram tratadas através do programa Quantikov para determinar a porosidade do filme e o tamanho médio de grão da ZEI. Os filmes apresentaram porosidade adequada para serem empregados como eletrólito das PaCOS (entre 0,2 e 0,4 % ) e tamanho médio de grão entre 2,0 e 6,0 µm. A técnica de aerografia é adequada para fabricar eletrólito de ZEI para PaCOS. Abstract in english To reduce the operating temperature of solid oxide fuel cells, structures with thin films electrolytes, deposited by spray coating on porous anode were developed. The slurries used for the fabrication of the films were prepared using appropriates suspensions with ytria-stabilized zirconia (YSZ) powe [...] rs, solvents, dispersants, binders and plasticizers appropriates. In this work the study of the influence of the binders in the stability of the suspensions and the microstructures properties of the YSZ films were done. Three slurries were made with different composition of binders (0.5; 1.0 and 2.0 % in weight). All of them showed pseudo-plastics and thixotropics flow behavior, according to viscosities measurements and shear rate. The films were sintered to 1500 ºC /6 hours. The images of scanning electron micrographs (SEM) were treated by Quantikov program to determine the porosity of the film and average grain size of YSZ. The films showed adequate porosity for being used as SOFC electrolyte (between 0.2 and 0.4%) and average grain size between 2.0 and 6.0 µ m. The spray coating is a suitable technique to fabricate the YSZ electrolytes for SOFC.

H.A., Taroco; R. M. F., Basaglia; R. Z., Domingues; M., Brant; T., Matencio.

2008-09-01

92

Chocolate rheology Reologia de chocolate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheology is the science that studies the deformation and flow of solids and fluids under the influence of mechanical forces. The rheological measures of a product in the stage of manufacture can be useful in quality control. The microstructure of a product can also be correlated with its rheological behavior allowing for the development of new materials. Rheometry permits attainment of rheological equations applied in process engineering, particularly unit operations that involve heat and mas...

Estela Vidal Gonçalves; Suzana Caetano da Silva Lannes

2010-01-01

93

Rheology of giant micelles  

CERN Document Server

Giant micelles are elongated, polymer-like objects created by the self-assembly of amphiphilic molecules (such as detergents) in solution. Giant micelles are typically flexible, and can become highly entangled even at modest concentrations. The resulting viscoelastic solutions show fascinating flow behaviour (rheology) which we address theoretically in this article at two levels. First, we summarise advances in understanding linear viscoelastic spectra and steady-state nonlinear flows, based on microscopic constitutive models that combine the physics of polymer entanglement with the reversible kinetics of self-assembly. Such models were first introduced two decades ago, and since then have been shown to explain robustly several distinctive features of the rheology in the strongly entangled regime, including extreme shear-thinning. We then turn to more complex rheological phenomena, particularly involving spatial heterogeneity, spontaneous oscillation, instability, and chaos. Recent understanding of these comp...

Cates, M E; Cates, Michael E.; Fielding, Suzanne M.

2006-01-01

94

Food Rheology; Folding Fun  

Science.gov (United States)

In this activity students analyze the rheologic and structural properties of various foods (everything from pudding to white bread) and think about how they expect them to behave under lateral pressure and how they will affect each other. They design experiments, run the experiments and then do lab write-ups. Depending on your emphasis, you can use this to help teach folding mechanics, rheology, why beds deform the way they do, decollements (pudding works great), deformation mechanisms, folding and even more. It is a single lecture activity, though the lead-in lecture and activity and clean-up take about 40-50 minutes.

Beutel, Erin

95

Rheology of liquid foam  

International Nuclear Information System (INIS)

Liquid foams can behave like solids or liquids, depending on the applied stress and on the experimental timescale. Understanding the origin of this complex rheology which gives rise to many applications and which resembles that of many other forms of soft condensed matter made of closely packed soft units requires challenging theoretical questions to be solved. We briefly recall the basic physics and physicochemistry of foams and review the experiments, numerical simulations and theoretical models concerning foam rheology published in recent years. (topical review)

96

Direct microwave-assisted synthesis of CuAlO{sub 2} for quasi-solid electrolyte used for dye sensitized solar cells  

Energy Technology Data Exchange (ETDEWEB)

A single phase of delafossite CuAlO{sub 2} (CAO) was produced by direct reaction of the mixture of aluminium nitrate nanohydrate (Al(NO{sub 3}){sub 3}.9H{sub 2}O) and copper acetate hydrate (Cu(CH{sub 3}COO){sub 2}.nH{sub 2}O) with 1:1 molar ratio of Cu:Al by a 600 W microwave radiation for 20 min. The direct microwave heating of the starting raw materials for the synthesis of CAO enabled us to save energy consumption. The optical properties of CAO powder were investigated, including the influence of CAO contents on the photocurrent density-voltage characteristic by forming a quasi-solid electrolyte (QSE) of a DSSC. As the results suggested that the effect of CAO in QSE was to improve the ionic conduction and charge transport properties of the redox system. The optimum CAO content to achieve the maximum value of J{sub SC} (0.333 mA/cm{sup 2}) and V{sub OC} (0.317 V) was 1%wt CAO. (orig.)

Suriwong, Tawat; Pongtornkulpanich, Anan; Sukchai, Sukruedee [Naresuan Univ., Phitsanulok (Thailand). School of Renewable Energy Technology; Thongtem, Titipun [Chiang Mai Univ. (Thailand). Dept. of Chemistry; Chiang Mai Univ. (Thailand). Materials Science Research Center; Thongtem, Somchai [Chiang Mai Univ. (Thailand). Dept. of Physics and Materials Science; Chiang Mai Univ. (Thailand). Materials Science Research Center

2012-07-01

97

Synthesis and properties of phenylindane-containing polybenzimidazole (PBI) for high-temperature polymer electrolyte membrane fuel cells (PEMFCs)  

Science.gov (United States)

A thermally stable and organo-soluble phenylindane-containing polybenzimidazole (phenylindane-PBI) was synthesized from 3,3?,4,4?-tetraaminobiphenyl and 1,1,3-trimethyl-3-phenylindan-4?,5-dicarboxylic acid using polyphosphoric acid (PPA) as both solvent and dehydrating agent. Polymerization conditions were carefully investigated to achieve high molecular weight polymers (IV = 1.00 dL g-1). To study the effects of backbone structure on properties, meta-PBI was also synthesized in PPA. It was found the introduction of rigid bent phenylindane moiety into the polymer backbone greatly improved the polymer solubility in polar aprotic solvents. The fabrication of acid-doped phenylindane-PBI membranes was attempted by both sol-gel and acid imbibing processes. The membranes prepared by the latter method showed a maximum proton conductivity of 0.061 S cm-1 at 180 °C with a phosphoric acid doping level of 10.0 PA/RU. Both phenylindane-PBI and meta-PBI membranes were fabricated into membrane electrode assemblies (MEAs) and tested to evaluate their fuel cell performance. The phosphoric acid doped phenylindane-PBI membrane exhibited comparable fuel cell performance as meta-PBI under similar testing conditions, demonstrating that it is a promising polymer electrolyte membrane candidate for high-temperature fuel cell applications.

Li, Xin; Chen, Xiaoming; Benicewicz, Brian C.

2013-12-01

98

Synthesis of nanocrystalline Ce(0.8)Gd(0.2)O(2-delta) electrolyte materials for IT-SOFC.  

Science.gov (United States)

We successfully synthesized nano-sized Ce(0.8)Gd(0.2)O(2-delta) powders by combustion method, using gelatin as fuel. The calcined powders showed high-quality characteristics, i.e., nano-scale size (14-35 nm) and narrow size distribution. The structural, morphological, and electrical characteristics of the sintered Ce(0.8)Gd(0.2)O(2-delta) were studied systematically, depending on sintering temperature. The crystal structure of the Ce(0.8)Gd(0.2)O(2-delta) belonged to the cubic fluorite structure. The gelatin-assisted combustion synthesized Ce(0.8)Gd(0.2)O(2-delta) powders allowed to sinter well at low temperature for dense and ultra-fine Ce(0.8)Gd(0.2)O(2-delta) electrolyte with good electrical conductivity. The sintering temperature of the Ce(0.8)Gd(0.2)O2 powder was approximately 300 degrees C lower than that of conventional solid-state synthesized powder. The nanopowder produced was sintered into pellets with relative densities over 99.1% of the theoretical value even at 1400 degrees C. The Ce(0.8)Gd(0.2)O(2-delta) sintered at 1400 degrees C exhibited a conductivity of 0.101 S/cm at 800 degrees C in air. PMID:21138014

Park, K; Choi, J W; Hwang, H K; Saradha, T

2010-11-01

99

Design and Synthesis of Cross-Linked Copolymer Membranes Based on Poly(benzoxazine and Polybenzimidazole and Their Application to an Electrolyte Membrane for a High-Temperature PEM Fuel Cell  

Directory of Open Access Journals (Sweden)

Full Text Available Elevated-temperature (100~200 °C polymer electrolyte membrane (PEM fuel cells have many features, such as their high efficiency and simple system design, that make them ideal for residential micro-combined heat and power systems and as a power source for fuel cell electric vehicles. A proton-conducting solid-electrolyte membrane having high conductivity and durability at elevated temperatures is essential, and phosphoric-acid-containing polymeric material synthesized from cross-linked polybenzoxazine has demonstrated feasible characteristics. This paper reviews the design rules, synthesis schemes, and characteristics of this unique polymeric material. Additionally, a membrane electrode assembly (MEA utilizing this polymer membrane is evaluated in terms of its power density and lifecycle by an in situ accelerated lifetime test. This paper also covers an in-depth discussion ranging from the polymer material design to the cell performance in consideration of commercialization requirements.

Hyuk Chang

2013-01-01

100

Rheology of planetary ices  

Energy Technology Data Exchange (ETDEWEB)

The brittle and ductile rheology of ices of water, ammonia, methane, and other volatiles, in combination with rock particles and each other, have a primary influence of the evolution and ongoing tectonics of icy moons of the outer solar system. Laboratory experiments help constrain the rheology of solar system ices. Standard experimental techniques can be used because the physical conditions under which most solar system ices exist are within reach of conventional rock mechanics testing machines, adapted to the low subsolidus temperatures of the materials in question. The purpose of this review is to summarize the results of a decade-long experimental deformation program and to provide some background in deformation physics in order to lend some appreciation to the application of these measurements to the planetary setting.

Durham, W.B. [Lawrence Livermore National Lab., CA (United States); Kirby, S.H.; Stern, L.A. [Geological Survey, Menlo Park, CA (United States)

1996-04-24

 
 
 
 
101

Rheology of Attractive Emulsions  

CERN Document Server

We show how attractive interactions dramatically influence emulsion rheology. Unlike the repulsive case, attractive emulsions below random close packing, RCP, can form soft gel-like elastic solids. However, above RCP, attractive and repulsive emulsions have similar elasticities. Such compressed attractive emulsions undergo an additional shear-driven relaxation process during yielding. Our results suggest that attractive emulsions begin to yield at weak points through the breakage of bonds, and, above RCP, also undergo droplet configurational rearrangements.

Datta, Sujit S; Rhodes, Travers S; Mason, Thomas G; Weitz, David A; 10.1103/PhysRevE.84.041404

2012-01-01

102

Electrolyte salts for nonaqueous electrolytes  

Science.gov (United States)

Metal complex salts may be used in lithium ion batteries. Such metal complex salts not only perform as an electrolyte salt in a lithium ion batteries with high solubility and conductivity, but also can act as redox shuttles that provide overcharge protection of individual cells in a battery pack and/or as electrolyte additives to provide other mechanisms to provide overcharge protection to lithium ion batteries. The metal complex salts have at least one aromatic ring. The aromatic moiety may be reversibly oxidized/reduced at a potential slightly higher than the working potential of the positive electrode in the lithium ion battery. The metal complex salts may also be known as overcharge protection salts.

Amine, Khalil; Zhang, Zhengcheng; Chen, Zonghai

2012-10-09

103

THE ANALYSIS OF CONCRETE RHEOLOGICAL CHARACTERISTICS BEHAVIOUR  

Directory of Open Access Journals (Sweden)

Full Text Available In the rheological models used in the mathematical description of the rheological behavior ofconcrete. Plays stiffness modulus variation, tangential effort, apparent viscosity, friction angle.

Ramona PIN?OI

2013-05-01

104

Rheological behavior study of a clay-polymer mixture: effects of the polymer addition  

International Nuclear Information System (INIS)

The aim of the present work is to establish a bibliographical synthesis on the microstructure, the colloidal and rheological characterization of bentonite suspensions with and without polymer/surfactant addition; to lead to a rheological characterization of clay-additive mixtures and to understand the interaction between the clay particles and polymer/surfactants. Different experimental measurements: rheology, particle sizing, and x-ray diffraction were used to study the rheological character of the water-bentonite-anionic additive mixtures (CMC, SDS, xanthane) as well as the nature of the particle-particle interactions and particle-additive. The modeling part led to the adoption of Tiu and Boger's model to predict the thixotropy of the bentonite suspensions without additive. Thus, a new model is proposed with physical parameters for a better correlation of the rheological behavior of the various studied mixtures. (author)

105

Synthesis of single-phase HgBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8+{delta}} high-T{sub c} superconducting films using the multistep electrolytic process  

Energy Technology Data Exchange (ETDEWEB)

We report on the use of the multistep electrolytic process for the synthesis of high-T{sub c} single-phase HgBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8+{delta}} (Hg-1223) superconducting films. The process includes: (i) deposition of BaCaCu precursor alloy; (ii) oxidation of BaCaCu films; (iii) electrolytic intercalation of Hg in precursor Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} films; (iv) electrochemical oxidation and annealing of Hg-intercalated Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} films to convert into Hg-1223. Films were characterized by thermo-gravimetric analysis and differential thermal analysis, x-ray diffraction and scanning electron microscopy. The electrolytic intercalation of Hg in Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} precursor proves to be a novel alternative to the high-temperature-high-pressure mercuration process. The films are single-phase Hg-1223 with T{sub c} = 121.5 K and J{sub c} = 4.3 x 10{sup 4} A cm{sup -2} at 77 K.

Shivagan, D D; Shirage, P M; Ekal, L A; Pawar, S H [School of Energy Studies, Department of Physics, Shivaji University, Kolhapur 416 004 (India)

2004-01-01

106

[Electrolyte disorders].  

Science.gov (United States)

Disorders of electrolyte balance are frequent and pathophysiologically complex. Sodium is responsible for a large part of the osmolarity of extracellular fluids. Therefore, pathological concentrations of serum sodium reflect the relation between sodium and water in the extracellular compartment rather than the total body sodium content. The causes of hypo- or hypernatremia can only be deduced if total body volume status is considered. Patients with hyponatremia and volume deficit should receive sodium chloride solution while patients with this disorder in the presence of volume overload need strict water restriction. In certain cases additional specific pharmacotherapy directed at the effects of antidiuretic hormone may be considered. Potassium and calcium are extracellular regulatory ions; their concentrations do not relevantly contribute to osmolarity and water distribution but to electrophysiologically relevant transmembrane potentials. These ions are influenced by active membrane transporters and regulated by several hormones. The rather small extracellular pools are overfilled or depleted by alterations of intake and excretion. In addition, several inborn or acquired defects of transmembrane transporters may severely alter their extracellular concentrations. Therapy needs to consider the specific mechanisms that led to the electrolyte disorder including modification of intake, excretion or extra-intracellular distribution. PMID:21681474

Girndt, M

2011-08-01

107

Non-aqueous electrolyte solutions  

Science.gov (United States)

Non-aqueous electrolyte solutions are nowadays intensively studied owing to their unique properties for their application in various electrochemical devices and procedures. Important advances have already been made in high-energy primary batteries, wet capacitors, electroplating, phase-transfer catalysis and electro-organic synthesis; advances are expected in further fields such as high-energy secondary batteries, non-emissive displays, solar cells, thin-film procedures and coating. A survey is given both for successful recent applications and expectations.

Gores, H.-J.; Barthel, J.

1983-10-01

108

Rheology of capsule suspension  

Science.gov (United States)

Rheology of suspension of liquid-filled elastic capsules in linear shear flow is studied by three-dimensional numerical simulations using a front-tracking method. First, we consider dilute suspension capsules of spherical resting shape for which only a steady tank- treading motion is observed. We find a novel result that the capsule suspension exhibits a shear viscosity minimum at moderate values of the viscosity ratio, and high capillary numbers. The shear viscosity minimum exists for capsules with area-dilating membranes, but not for those with nearly-incompressible membranes. Physical mechanisms underlying these results are studied by decomposing the particle stress tensor into a contribution due to the elastic stresses in the capsule membrane, and a contribution due to the viscosity differences between the internal and suspending fluids. It is shown that the elastic contribution is shear-thinning, but the viscous contribution is shear-thickening. We then consider dilute suspension of oblate shape capsules which undergo unsteady motion such as swinging and tumbling. The effect of such unsteady dynamics on time-dependent rheology is addressed. Finally, we consider dense suspension, and observe that the shear viscosity minimum disappears with increasing capsule volume fraction.

Bagchi, Prosenjit; Murthy Kalluri, R.

2010-11-01

109

Rheology of coal suspensions  

Energy Technology Data Exchange (ETDEWEB)

Proper design of operations encountered in preparation, transport and employment of suspensions like coal slurries and coal-oil mixtures require an accurate knowledge of their rheological behaviour. Such concentrated suspensions generally exhibit non-Newtonian behaviour (shear-thinning) which is more pronounced at higher coal concentrations. The nature of the dispersing medium influences the aggregation state of the disperse phase and consequently affects the stability and the rheology of the systems. In the present paper coal suspensions prepared with different dispersing media and covering a wide range in solid phase concentration are studied by using a rotational coaxial cylinders viscometer. Different models have been taken into consideration for correlating experimental data. In particular, in order to describe the dependence of viscosity on shear rate and solid phase concentration, the suitability of the model suggested by Smith and Bruce is evaluated. Accordingly, the aggregation state of the disperse phase as well as its dependence on shear rate and dispersing medium can be estimated.

Alessandrini, A.; Kikic, I.; Lapasin, R.

1983-01-01

110

Solid state electrolyte systems  

Energy Technology Data Exchange (ETDEWEB)

Lanthanum gallates are a new family of solid electrolytes that exhibit high ionic conductivity and are stable to high temperatures. Compositions have been developed that are as much as a factor of two more conductive than yttria-stabilized zirconia at a given temperature, through partial replacement of lanthanum by calcium, strontium, and/or barium and through partial replacement of gallium by magnesium. Oxide powders were prepared using combustion synthesis techniques developed in this laboratory; these were sintered to >95% of theoretical density and consisted of a single crystalline phase. Electrical conductivities, electron and ion transference numbers, thermal expansion, and phase behavior were evaluated as a function of temperature and oxygen partial pressure. A key advantage of the use of lanthanum gallate electrolytes in solid oxide fuel cells is that the temperature of operation may be lowered to perhaps 800 C, yet provide approximately the same power density as zirconia-based cells operating at 1000 C. Ceramic electrolytes that conduct both oxygen ions and electrons are potentially useful to passively separate pure oxygen from an air source at low cost. In such materials, an oxygen ion flux in one direction is charge-compensated by an opposing electron flux. The authors have examined a wide range of mixed ion and electron conducting perovskite ceramics in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, where M = Sr, Ca, and Ba, and N = Pr, Mn, Ni, Cu, Ti, and Al, as well as mixed conducting brownmillerite ceramics, and have characterized oxygen permeation behavior, defect chemistry, structural and phase stability, and performance as cathodes.

Pederson, L.R.; Armstrong, B.L.; Armstrong, T.R. [Pacific Northwest Lab., Richland, WA (United States)] [and others

1997-12-01

111

Rheology for chemists an introduction  

CERN Document Server

Rheology is primarily concerned with materials: scientific, engineering and everyday products whose mechanical behaviour cannot be described using classical theories. From biological to geological systems, the key to understanding the viscous and elastic behaviour firmly rests in the relationship between the interactions between atoms and molecules and how this controls the structure, and ultimately the physical and mechanical properties. Rheology for Chemists An Introduction takes the reader through the range of rheological ideas without the use of the complex mathematics. The book gives part

Goodwin, J W

2008-01-01

112

Synthesis of single-crystalline ZnO nanowires and their applications in dye-sensitized solar cells (DSSCs) with a solid polyethylene glycol (PEG) redox electrolyte.  

Science.gov (United States)

We demonstrate for the first time ZnO nanowire dye-sensitized solar cells (DSSCs) with a solid-state poly (ethylene glycol) (PEG) redox electrolyte. From the current-voltage characteristics of this solid PEG electrolyte-based ZnO nanowire DSSCs, the open-circuit voltage and short-circuit current density, and fill factor were determined to be approximately 0.58 V, approximately 1.30 mA/cm2, and 0.31, respectively. We obtained a power conversion efficiency of approximately 0.24% under an incident irradiation of 100 mW/cm2, corresponding to air mass (AM) 1.5 global solar conditions. The solid-state DSSC experienced an efficiency that was approximately 0.1% lower than the efficiency a liquid electrolyte based ZnO nanowire DSSC. PMID:19198401

Hyung, Jung-Hwan; Suh, Duk-Il; Chun, Ji-Min; Yang, O-Bong; Suh, Eun-Kyung; Lee, Sang-Kwon

2008-10-01

113

Rheological behaviour of nanofluids  

International Nuclear Information System (INIS)

This work aims at a more fundamental understanding of the rheological behaviour of nanofluids and the interpretation of the discrepancy in the recent literature. Both experiments and theoretical analyses are carried out with the experimental work on ethylene glycol (EG)-based nanofluids containing 0.5-8.0 wt% spherical TiO2 nanoparticles at 20-60 0C and the theoretical analyses on the high shear viscosity, shear thinning behaviour and temperature dependence. The experimental results show that the EG-based nanofluids are Newtonian under the conditions of this work with the shear viscosity as a strong function of temperature and particle concentration. The relative viscosity of the nanofluids is, however, independent of temperature. The theoretical analyses show that the high shear viscosity of nanofluids can be predicted by the Krieger-Dougherty equation if the effective nanoparticle concentration is used. For spherical nanoparticles, an aggregate size of approximately 3 times the primary nanoparticle size gives the best prediction of experimental data of both this work and those from the literature. The shear thinning behaviour of nanofluids depends on the effective particle concentration, the range of shear rate and viscosity of the base liquid. Such non-Newtonian behaviour can be characterized by a characteristic shear rate, which decreases with increasing volume fraction, increasing base liquid viscosity, or increasing aggregate size. These fity, or increasing aggregate size. These findings explain the reported controversy of the rheological behaviour of nanofluids in the literature. At temperatures not very far from the ambient temperature, the relative high shear viscosity is independent of temperature due to negligible Brownian diffusion in comparison to convection in high shear flows, in agreement with the experimental results. However, the characteristic shear rate can have strong temperature dependence, thus affecting the shear thinning behaviour. The theoretical analyses also lead to a classification of nanofluids into dilute, semi-dilute, semi-concentrated and concentrated nanofluids depending on particle concentration and particle structuring

114

Study of an industrial process for the synthesis of high molar mass ethylene oxide-propylene oxide copolymers usable as extrusible electrolyte; Etude d`un procede industriel de synthese de copolymeres oxyde d`ethylene-oxyde de propylene de hautes masses molaires utilisables comme electrolyte extrudable  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is to develop an industrial process for the synthesis of an extrusible electrolyte polymer for lithium batteries. From literature data and precise specifications the high molar mass EO/OP copolymers synthesis by coordinative catalysis has been studied in order to reach a high productivity and to minimize the treatment steps. Two catalytic systems have been studied: the aluminium alkoxide-based Vandenberg-type catalysis and the calcium alcoholate amides catalysis. The first catalysis performed in solution gives excellent results. Its adaptation to silicon supported catalysis leads to a directly usable polymer in suspension but the productivity falls down and remains to be optimized. The calcium amide catalysis in heptane suspension generates acceptable productivities but also a too high proportion of low molar masses. Various approaches have been studied to minimize this proportion due to the presence of secondary sites that generate a cationic mechanism. The two synthesis ways explored are promising but remain to be optimized in order to increase the productivity of the efficient catalytic site and to reduce the formation of low molar masses generated by parasite catalytic sites. (J.S.) 9 refs.

Gramain, Ph. [Ecole Nationale Superieure de Chimie de Montpellier, 34 (France); Caselles, E. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France)

1996-12-31

115

Rheology of carbon nanotube dispersions  

CERN Document Server

We report on rheological properties of a dispersion of multi-walled carbon nanotubes in a viscous polymer matrix. Particular attention is paid to the process of nanotubes mixing and dispersion, which we monitor by the rheological signature of the composite. The response of the composite as a function of the dispersion mixing time and conditions indicates that a critical mixing time t* needs to be exceeded to achieve satisfactory dispersion of aggregates, this time being a function of nanotube concentration and the mixing shear stress. At shorter times of shear mixing, tt*, has several universal rheological features; at nanotube concentration above a characteristic value ~2-3wt% the effective elastic gel network is formed, while the low-concentration composite remains a viscous liquid. We use this rheological approach to determine the effects of aging and re-aggregation.

Huang, Y Y; Terentyev, E M

2006-01-01

116

Rheological properties of polypropylene nanocomposites  

International Nuclear Information System (INIS)

In this work, composites of polypropylene with a master batch to obtain clay containing nano composites were obtained. The materials were characterized by X ray diffraction, small angle X-ray scattering and by rheological analysis. (author)

117

Rheological measurements on cement grouts  

International Nuclear Information System (INIS)

This report describes the techniques which have been developed at Winfrith for assessing the rheological properties of cement grouts. A discussion of the theory of rheology and its application to cement is given and the methodology for calibrating a special paddle measuring system for a commercial viscometer is described. The use of the system for determining flow curves, equilibrium viscosity, viscosity as a function of shearing time and structure changes is also discussed. (author)

118

Plant cell suspension culture rheology.  

Science.gov (United States)

The results of rheological measurements on 10 different plant cell suspension cultures are presented. Nicotiana tabacum (tobacco) suspension cultures grown in serial batch subculture display high viscosity and power law rheology. This "undesirable" rheology is shown to be a result of elongated cell morphology. The rheology of Papaver somniferum (poppy) cell suspensions is quite different; poppy suspensions behave as Newtonian fluids and have relatively low viscosity (less than 15 cP) at fresh cell densities up to 250 g/L. This flow behavior can be attributed to a lack of elongation in batch-grown poppy cells. A simple correlation for the viscosity as a function of cell density is developed for poppy suspensions up to 300 g fresh weight (FW)/L. It is shown that tobacco cells do not elongate when grown in semicontinuous culture (daily media replacement). These semicontinuously cultured cells have rheological behavior that is indistinguishable from that of poppy, further confirming the dependence of rheology on plant cell morphology. The rheology of a wide variety of other plant suspensions at 200 g FW/L is presented. Most cell suspensions, including soybean, cotton, bindweed, and potato, display low viscosities similar to poppy suspensions. Only carrot and atriplex exhibit slight pseudoplastic behavior which corresponded to a slight degree of cellular elongation for these cultures. This demonstrates that complex rheology associated with elongated cell morphology is much less common than low-viscosity Newtonian behavior. High viscosity in plant cell culture is therefore not an intrinsic characteristic of plant cells but, instead, is a result of the ability to grow cultures to extremely high cell densities due to low biological oxygen demand. PMID:18613057

Curtis, W R; Emery, A H

1993-08-01

119

Rheological Modifiers and Wetting Agents  

International Nuclear Information System (INIS)

DOE tank waste treatment plants, the Waste Treatment Plant (WTP) at Hanford and Defense Waste Processing Facility (DWPF) at Savannah River, are designed to vitrify radioactive waste slurries for long-term storage. Plant throughput is currently limited by the waste solids loading. To increase waste throughput rates in the plant, an increase in the slurry solids concentration (or conversely, a reduction in the mass fraction of water in the waste) is being considered. However, the present mechanical designs used to mix and transport theses slurries are limited by the rheological properties. This reduction of water results in an increase in rheological properties that challenge plant design and performance. To support this increase in throughput, there is a need to reduce the rheological properties of these waste slurries. The objective of this project is to determine a small set of well-performing and commercially available rheological modifiers that allow control rheological properties of various simulated and actual waste slurries and to understand the physical mechanisms that govern modification of waste rheology. It is estimated that processing at a higher solids concentration will reduce the operating life of these plants by one year for both facilities, representing roughly $1B in lifecycle cost savings. In addition, this research is potentially important to sustainable operations of both WTP and DWPF

120

Synthesis, processing and characterization of the solid oxide half-cells cathode/electrolyte of strontium-doped lanthanum manganite/Yttria-stabilized zirconia  

International Nuclear Information System (INIS)

The ceramic films of strontium-doped lanthanum manganite (LSM) and strontium doped lanthanum manganite/Yttria-stabilized zirconia (LSM/YSZ) are used as cathodes of the high temperature solid oxide fuel cells (HTSOFC). These porous ceramic films had been deposited on the YSZ dense ceramic substrate, used as electrolyte, structural component of the module, thus conferring a configuration of half-cell called auto-support. The study of the half-cell it is basic, therefore in the interface cathode/electrolyte occurs the oxygen reduction reaction, consequently influencing in the performance of the HTSOFC. In this direction, the present work contributes for the processing of thin films, using the wet powder spraying technique, adopted for the conformation of the ceramic films for allowing the attainment of porous layers with thicknesses varied in the order of micrometers. The LSM powders were synthesized by the citrate technique and the LSM/YSZ powders synthesized by the solid mixture technique. In the stage of formation were prepared organic suspensions of LSM and LSM/YSZ fed by gravity in a manual aerograph. For the formation of the YSZ substrate was used a hydraulic uniaxial press. The attainment of solid oxide half-cells cathode/electrolyte was possible of crystalline structures hexagonal for phase LSM and cubic for phase YSZ. The half-cells micrographs show that the YSZ substrate is dense, enough to be used as solid electrolyte, and the LSM and LSM/YSZ films are presented porous with approximately 30 ?m of thickness and good adherence between the cathodes and the electrolyte. The presence of composite cathode between the LSM cathode and YSZ substrate, presented an increase in the electrochemical performance in the oxygen reduction reaction. (author)

 
 
 
 
121

Rheological characterization of nuclear waste using falling-ball rheometry  

International Nuclear Information System (INIS)

Knowledge of the rheological properties of saturated solutions containing solid particles is very important in nuclear waste management technology. For example, the nuclear waste in the Hanford Site high-level radioactive waste tanks contains strong electrolyte solutions with a high concentration of solids. Previous attempt using rotational viscometers to determine the rheology has shown unusual thixotropic and shear thinning behaviors with a lack of reproducibility. Using falling-ball rheometry, the rheology of the undisturbed simulant may be determined with much better reproducibility. In this study, a well-mixed simulant which has similar chemical composition to the actual waste will be tested. Falling-ball size and density will be varied to get data in a wide range of shear rates. To determine the rheogram, several methods will be tried to match the observed data. Based on these tests, a rheogram can be determined from the model and its best-fit parameters. The simulant shows shear-thinning behavior and a yield stress. This would suggest a H-B model. But when fitting to one of the simulants which showed a very low yield stress, the predictions assuming no yield and assuming yield resulted in no improvement in the fit when assuming yield

122

Rheology and Structure of Molten, Olefin Multiblock Copolymers  

Energy Technology Data Exchange (ETDEWEB)

Several samples of a recently developed olefin multiblock copolymer were studied by means of rheology, differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS). The synthesis involves a chain shuttling agent (CSA) that switches the growing chain between two catalysts, one that favors the incorporation of an {alpha}-olefin comonomer and one that suppresses incorporation. The data were used to determine the effect of octene comonomer content and CSA level on rheological behavior and the occurrence of mesophase separation transition (MST) in the melt. To distinguish between crystallization and MST, we made calorimetry scans and measured the density and rheological properties over a range of temperatures. Small angle X-ray scattering analysis of a sample that had undergone planar extensional flow revealed strong alignment of lamellar mesodomains, which maintained their alignment after annealing. This result confirmed the hypothesis based on rheological evidence that a lamellar mesophase is present in the melt at temperatures well above the melting point.

Park, Heon E.; Dealy, John M.; Marchand, Gary R.; Wang, Jian; Li, Sheng; Register, Richard A. (McGill); (Dow); (Princeton)

2010-12-07

123

Surface rheology and interface stability.  

Energy Technology Data Exchange (ETDEWEB)

We have developed a mature laboratory at Sandia to measure interfacial rheology, using a combination of home-built, commercially available, and customized commercial tools. An Interfacial Shear Rheometer (KSV ISR-400) was modified and the software improved to increase sensitivity and reliability. Another shear rheometer, a TA Instruments AR-G2, was equipped with a du Nouey ring, bicone geometry, and a double wall ring. These interfacial attachments were compared to each other and to the ISR. The best results with the AR-G2 were obtained with the du Nouey ring. A Micro-Interfacial Rheometer (MIR) was developed in house to obtain the much higher sensitivity given by a smaller probe. However, it was found to be difficult to apply this technique for highly elastic surfaces. Interfaces also exhibit dilatational rheology when the interface changes area, such as occurs when bubbles grow or shrink. To measure this rheological response we developed a Surface Dilatational Rheometer (SDR), in which changes in surface tension with surface area are measured during the oscillation of the volume of a pendant drop or bubble. All instruments were tested with various surfactant solutions to determine the limitations of each. In addition, foaming capability and foam stability were tested and compared with the rheology data. It was found that there was no clear correlation of surface rheology with foaming/defoaming with different types of surfactants, but, within a family of surfactants, rheology could predict the foam stability. Diffusion of surfactants to the interface and the behavior of polyelectrolytes were two subjects studied with the new equipment. Finally, surface rheological terms were added to a finite element Navier-Stokes solver and preliminary testing of the code completed. Recommendations for improved implementation were given. When completed we plan to use the computations to better interpret the experimental data and account for the effects of the underlying bulk fluid.

Yaklin, Melissa A.; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Walker, Lynn; Koehler, Timothy P.; Reichert, Matthew D. (Carnegie Mellon University, Pittsburgh, PA); Castaneda, Jaime N.; Mondy, Lisa Ann; Brooks, Carlton, F.

2010-11-01

124

Synthesis, characterization and electrical properties of solid electrolyte for solid oxide fuel cell; Preparacao, caracterizacao e propriedades eletricas de eletrolito solido para celula a combustivel de oxido solido  

Energy Technology Data Exchange (ETDEWEB)

Solid electrolytes of BaCe{sub 08}Gd{sub O29} were prepared by the polymeric precursor method. X-ray diffraction data shows a single phase with orthorhombic crystalline structure. The densification process was followed by scanning electronic microscopy and apparent density measurements. The apparent density was developed for different temperatures of sintering, reaching > 96% for sintered temperature of 1550 {sup 0}C deg . The electrochemical impedance analysis was development in the temperature of 400-700 deg C, in air atmosphere at 700 deg C a value of 30,6 mS.cm{sup -1} was obtained. The results of conductivity have confirmed the gadolinium doped barium cerate has a great potential for use as solid electrolyte for intermediate temperature solid oxide fuel cell, at experimental controlled conditions. (author)

Berton, Marco Antonio Coelho; Garcia, Carlos Mario; Matos, Jeferson Hrenechen [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], Emails: felsky@latec.org.br, garcia@latec.org.br, jeferson.h@latec.org.br

2010-04-15

125

Dry granular flows: rheological measurements of the I-Rheology  

CERN Document Server

Granular materials do not flow homogeneously like fluids when submitted to external stress,but often form rigid regions that are separated by narrow shear bands where the material yields and flows. This shear localization impacts their apparent rheology, which makes it difficult to infer a constitutive behaviour from conventional rheometric measurements. Moreover, they present a dilatant behaviour, which makes their study in classical fixedvolume geometries difficult. These features led to perform extensive studies with inclined plane flows, which were of crucial importance for the development and the validation of the $\\mu(I)$ rheology. Our aim is to develop a method to characterize granular materials with rheometrical tools. Using unusual rheometry measurements in an annular shear cell adapted from Boyer et al. (2011), dense granular flows are studied. A focus is placed on the comparison between the present results and the I-rheology.

Fall, Abdoulaye; Hautemayou, David; Mézière, Cédric; Roux, Jean-Noël; Chevoir, François

2014-01-01

126

Fluid and Electrolyte Balance  

Science.gov (United States)

... They are in your blood, urine and body fluids. Maintaining the right balance of electrolytes helps your ... them from the foods you eat and the fluids you drink. Levels of electrolytes in your body ...

127

Molten salt electrolyte separator  

Science.gov (United States)

A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.

Kaun, Thomas D. (New Lenox, IL)

1996-01-01

128

Synthesis of poly(ionic liquids) both in solution and on surface of silica nanoparticles as novel quasi-solid state electrolytes  

Science.gov (United States)

Ionic liquids (ILs) are compounds composed of cations and anions with low melting point, usually below room temperature. ILs have some unique properties, such as high intrinsic ionic conductivity, non-volatility, non-flammability, thermal and chemical stability. Based on these properties, ILs have been considered as promising electrolyte materials. However, the sealing and fabrication of IL electrolytes remained a challenge in industry applications due to their liquid property. One way to solve this problem was to polymerize the ILs. Compared to ILs, poly(ionic liquids) (PILs) have enhanced mechanical stability, improved processability and durability. However, PILs have their own drawback, which is that once polymerized, the ionic conductivity of PILs drops a lot, usually several orders of magnitude lower than that of their monomers. To successfully apply PILs as electrolyte materials, the ionic conductivity must be improved. To have high conductivity, the PILs synthesized must have low Tgs. A series of low Tg polymer polyepichlorohydrin (polyEPCH) with molecular weight ranging from 22,000 to 76,000 were synthesized by anionic ring-opening polymerization. After quaternarization and ion exchange, a novel family of PIL electrolytes were synthesized and characterized. The PILs obtained showed not only low T g, high conductivity and good thermal stability, but also a high viscosity, which is beneficial in fabricating process. To get even higher conductivity, another low T g monomer, 2-((2-(2-(2-methoxyethoxy)ethoxy)ethoxy)methyl)oxirane (ME 3MO), was synthesized and randomly copolymerized with EPCH by cationic ring-opening polymerization. The resulting copolymer (polyEPCH-co -polyME3MO) was quaternarized and ion exchanged to form a PIL copolymer (polyGBIMTFSI-co-polyME3MO). By tuning the monomer composition, a series of PIL copolymers from polyGBIMTFSI- co-polyME3MO-8/1 to polyGBIMTFSI-co-polyME 3MO-1/4 were synthesized. All PIL copolymer samples showed higher ionic conductivity than PIL homopolymer. Among them, polyGBIMTFSI-co-polyME 3MO-1/1 showed the highest ionic conductivity (around 1.2 x 10 -4 S/cm at 25 °C), which was more than 1 order of magnitude higher than PIL homopolymer (9.3 x 10-6 S/cm at 25 °C). We also synthesized PILs on the surface of silica nanoparticles via surface initiated atom transfer radical polymerization (ATRP). A gel electrolyte was formed by dispersing the PIL/silica nanocomposites in 1-methyl-3-propylimidazolium iodide and heating for 1 h. The gel electrolyte was used as a quasi-solid state electrolyte in DSSC and a 0.37 % conversion efficiency was achieved.

Hu, Heyi

129

Rheological approaches to food systems  

Science.gov (United States)

Foods, consumer products and cosmetics belong to a wide range of colloidal and non-colloidal materials. Often, they are composite materials comprising several classes of fluid and solid constituents, including biopolymer gels, particulate suspensions, emulsions and foams. Length scales relevant for such materials may be anywhere between those associated with the molecular conformation of the ingredients up to long-scale dimensions of processing flows. The corresponding time scales may be in the sub-millisecond regime during aggregation of the ingredients or up to years during the shelf life of the final product. Rheological research of food material focuses on both the interaction between its ingredients, which might exhibit a complex rheological response function themselves and the influence of processing on the food structure and its properties. This brief overview summarizes suitable food rheology approaches and is grouped by the degree of abstraction of length scales and interactions. To cite this article: P. Fischer et al., C. R. Physique 10 (2009).

Fischer, Peter; Pollard, Michael; Erni, Philipp; Marti, Irene; Padar, Stefan

2009-11-01

130

Rheological Behaviour of Raw Cement  

Directory of Open Access Journals (Sweden)

Full Text Available A series of rheometric tests was conducted on raw cement at different concentrations and particle finesses as well. The paste of raw cement, formed by a set of particles suspensions in water, presents rheological properties that make it different from the fluids commonly used. The obtained results have showed that the rheological behaviour is the shear-thinning type and can be described satisfactorily by a model of Herschel-Bulkley, characterized by three parameters ?0, K and n which connect the shear stress to the shear rate. In addition, the parameter ?0 was correlated by an exponential function of the volume concentration of particles, this correlation is valid for both the raw cement and limestone. This latter is the main component of raw cement, for that reason its rheology has been studied.

A. Lachemet

2008-01-01

131

Nanoporous polymer electrolyte  

Science.gov (United States)

A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

Elliott, Brian (Wheat Ridge, CO); Nguyen, Vinh (Wheat Ridge, CO)

2012-04-24

132

Electrolyte vapor condenser  

Science.gov (United States)

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

1983-02-08

133

Solid-state mechanochemical synthesis of CsHSO{sub 4} and 1,2,4-triazole inorganic-organic composite electrolytes for dry fuel cells  

Energy Technology Data Exchange (ETDEWEB)

Inorganic-organic composite electrolytes for use in dry fuel cells were synthesized from CsHSO{sub 4} (CHS) and 1,2,4-triazole (Tz). CHS and Tz were mechanochemically treated in a dry nitrogen atmosphere to obtain composites with xCHS.(100 - x)Tz, where x is the amount (mol) and was varied in increments of 10 between 90 and 50. Structural investigation of the composites indicated that chemical interactions occurred between CHS and Tz after solid-state mechanochemical treatment. The proton conductivity of the composite electrolytes was largely increased by introduction of Tz, particularly in the low temperature region. The composite with x = 80 showed high proton conductivity (6.0 x 10{sup -4} to 1.60 x 10{sup -3} S cm{sup -1}) over a wide temperature range (60-160 {sup o}C) in a dry atmosphere. These observations suggest that proton transfer in the CHS and Tz composite systems includes the proton-hopping mechanism and self-dissociation. This phenomenon probably supports proton diffusion, especially in low temperature regions.

Oh, Song-Yul, E-mail: ms089203@tutms.tut.ac.j [Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Yoshida, Toshihiro [Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Kawamura, Go [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Muto, Hiroyuki [Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@ee.tut.ac.j [Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

2011-02-01

134

Synthesis, Multinuclear NMR Characterization and Dynamic Property of Organic-Inorganic Hybrid Electrolyte Membrane Based on Alkoxysilane and Poly(oxyalkylene) Diamine  

Science.gov (United States)

Organic–inorganic hybrid electrolyte membranes based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) complexed with LiClO4 via the co-condensation of tetraethoxysilane (TEOS) and 3-(triethoxysilyl)propyl isocyanate have been prepared and characterized. A variety of techniques such as differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, alternating current (AC) impedance and solid-state nuclear magnetic resonance (NMR) spectroscopy are performed to elucidate the relationship between the structural and dynamic properties of the hybrid electrolyte and the ion mobility. A VTF (Vogel-Tamman-Fulcher)-like temperature dependence of ionic conductivity is observed for all the compositions studied, implying that the diffusion of charge carriers is assisted by the segmental motions of the polymer chains. A maximum ionic conductivity value of 5.3 × 10?5 Scm?1 is obtained at 30 °C. Solid-state NMR results provide a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains. PMID:24958176

Saikia, Diganta; Pan, Yu-Chi; Kao, Hsien-Ming

2012-01-01

135

Synthesis, Multinuclear NMR Characterization and Dynamic Property of Organic–Inorganic Hybrid Electrolyte Membrane Based on Alkoxysilane and Poly(oxyalkylene Diamine  

Directory of Open Access Journals (Sweden)

Full Text Available Organic–inorganic hybrid electrolyte membranes based on poly(propylene glycol-block-poly(ethylene glycol-block-poly(propylene glycol bis(2-aminopropyl ether complexed with LiClO4 via the co-condensation of tetraethoxysilane (TEOS and 3-(triethoxysilylpropyl isocyanate have been prepared and characterized. A variety of techniques such as differential scanning calorimetry (DSC, Fourier transform infrared (FTIR spectroscopy, alternating current (AC impedance and solid-state nuclear magnetic resonance (NMR spectroscopy are performed to elucidate the relationship between the structural and dynamic properties of the hybrid electrolyte and the ion mobility. A VTF (Vogel-Tamman-Fulcher-like temperature dependence of ionic conductivity is observed for all the compositions studied, implying that the diffusion of charge carriers is assisted by the segmental motions of the polymer chains. A maximum ionic conductivity value of 5.3 × 10?5 Scm?1 is obtained at 30 °C. Solid-state NMR results provide a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains.

Hsien-Ming Kao

2012-06-01

136

New polysaccharide-based polymer electrolytes; Nouveaux electrolytes polymeres a base de polysaccharides  

Energy Technology Data Exchange (ETDEWEB)

Polysaccharides like cellulose and chitosan are known for their filmic properties. This paper concerns the synthesis and the study of chitosan-based polymer electrolytes. A preliminary work concerns the study of glucosamine reactivity. The poly-condensation of chitosan ethers (obtained by reaction with ethylene oxide or propylene oxide) with bifunctional and monofunctional oligo-ethers leads to the formation of thin lattices (10 {mu}m) having excellent mechanical properties. The presence of grafted polyether chains along the polysaccharide skeleton allows to modify the vitreous transition temperature and the molecular disorder of the system. Two type of polymer electrolytes have been synthesized: electrolytes carrying a dissolved alkaline metal salt and ionomers. The analysis of their thermal, dynamical mechanical, nuclear magnetic relaxation, electrical, and electrochemical properties shows that this new class of polymer electrolytes has the same performances as ethylene poly-oxide based amorphous lattices plus the advantage of having good filmic properties. Abstract only. (J.S.)

Velasquez-Morales, P.; Le Nest, J.F.; Gandini, A. [Ecole Francaise de Papeterie et des Industries Graphique, 38 - Saint Martin d`Heres (France)

1996-12-31

137

Composite polyether electrolytes with Lewis acid type additives  

Energy Technology Data Exchange (ETDEWEB)

Polymer electrolytes based on low molecular weight poly(ethylene glycol)s doped with LiClO{sub 4} (0.1-1 mol kg PEG) and containing up to 10 mass% of AlBr{sub 3} additive were synthesized and characterized by impedance spectroscopy, FT-IR, DSC and rheological techniques. It has been found that addition of small amount (up to 5 mass%) of AlBr{sub 3} increases electrolytes conductivity in comparison with pure PEG-LiClO{sub 4} electrolytes for samples containing 1 mol of LiClO{sub 4} per kg PEG. Room temperature conductivity as high as 3x10{sup -4} S/cm was measured. For higher AlBr{sub 3} concentrations stiffening of the polymer organic electrolyte was observed which results in a decrease in the ionic conductivity. The systematic studies of the interfacial phenomena performed in the symmetrical cell comprising two lithium electrodes separated by PEG-LiClO{sub 4}-AlBr{sub 3} electrolyte allow us to postulate different rate of SEI (solid electrolyte interface) formation and limitation of its growth in the presence of AlBr{sub 3} interface thus enhancing the effectiveness of lithium cells. (author)

Borkowska, R.; Reda, A.; Zalewska, A.; Wieczorek, W. [Warsaw Univ. of Technology (Poland). Faculty of Chemistry

2001-07-01

138

Synthesis and characterization of polyether urethane acrylate-LiCF 3SO 3-based polymer electrolytes by UV-curing in lithium batteries  

Science.gov (United States)

The prepolymers of polyether urethane acrylate (PEUA) were synthesized from polyether polyol (polyethylene glycol (PEG) or polypropylene glycol (PPG)), diisocyanate (hexamethylene diisocyanate (HMDI) or toluene 2,4-diisocyanate (TDI)), and the caprolactone-modified hydroxyethyl acrylate (FA2D) using the catalyst (dibutyltin dilaurate (DBTDL)) by stepwise addition reaction. Lithium triflate (LiCF 3SO 3) was dissolved in PEUA prepolymers, and plasticizer (propylene carbonate (PC)) was added into prepolymer and salt mixtures. Then photoinitiator (Irgacure 184) was also dissolved in the mixtures. Thin films were prepared by casting on the glass plate, and then by curing the plasticized prepolymer and salt mixtures under UV radiation. Electrochemical and electrical properties of PEUA-LiCF 3SO 3-based polymer electrolytes were evaluated and discussed to be used in lithium batteries.

Kim, Cheon-Soo; Kim, Bo-Hyun; Kim, Keon

139

Synthesis and Characterization of Nafion-SiO2 Composite Membranes as an Electrolyte for Medium Temperature and Low Relative Humidity  

Directory of Open Access Journals (Sweden)

Full Text Available The weakness of the Nafion membrane as electrolyte of PEMFC associated with physical properties that is easy to shrink at temperatures above 80°C due to dehydration. Shrinkage will decrease the conductivity and membrane damage. Nafion-SiO2 composite membranes can improve membrane stability. The role of SiO2 in the Nafion clusters is as water absorbent cause the membrane remains wet at high temperatures and low humidity and conductivity remains high. The results showed the content of 2.8 wt% of SiO2 in the Nafion membrane, the conductivity of composite membrane is higher than the pure Nafion membrane that are 0.127 S cm-1 in dry conditions and 0.778 S cm-1 in wet conditions at room temperature. Compared with the pure Nafion membrane conductivity are 0.0661 S cm-1 and 0.448 S cm-1 respectively in dry and wet conditions.

Endang Sulistyowati

2011-12-01

140

Synthesis and ceramic processing of zirconia alumina composites for application as solid oxide fuel cell electrolytes; Sintese e processamento de compositos de zirconia-alumina para aplicacao como eletrolito em celulas a combustivel de oxido solido  

Energy Technology Data Exchange (ETDEWEB)

The global warmness and the necessity to obtain clean energy from alternative methods than petroleum raises the importance of developing cleaner and more efficient systems of energy generation, among then, the solid oxide fuel cell (SOFC). Cubic stabilized zirconia (CSZ) has been the most studied material as electrolyte in SOFC, due to its ionic conductivity and great stability at operation conditions. However, its low fracture toughness difficulties its application as a thin layer, what could lead to an improvement of cell efficiency. In this sense, the alumina addition in CSZ forms a composite, which can shift its mechanical properties, without compromising its electrical properties. In this work, coprecipitation synthesis route and ceramic processing of zirconia-alumina composites were studied, in order to establish optimum conditions to attain high density, homogeneous microstructure, and better mechanical properties than CSZ, without compromising ionic conductivity. For this purpose, composites containing up to 40 wt % of alumina, in a 9 mol % yttria-stabilized zirconia (9Y-CSZ) matrix were evaluated. In order to optimize the synthesis of the composites, a preliminary study of powder obtaining and processing were carried out, at compositions containing 20 wt % of alumina, in 9Y-CSZ. The ceramic powders were characterized by helium picnometry, X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, differential scanning calorimetry, granulometry by laser diffraction and gas adsorption (BET). The characterization of sinterized compacts were performed by X-ray diffraction, scanning electron microscopy, optical microscopy, density measurements, Vickers indentation and impedance spectroscopy. The obtained results show that the alumina addition, in the 9Y-CSZ matrix powders, raises the specific surface area, promotes deagglomeration of powders and elevates the oxides crystallization temperature, requiring higher energetic thermal treatments to attain high densities. In relation to the sintered products, it was confirmed the excellent homogeneity and crystallinity of microstructure provided by the chosen route, the restriction of grain growth by alumina addition, raise of hardness and fracture toughness, and higher ionic conductivity, even tough a lower bulk conductivity. These results indicate that the addition of 5 wt % alumina in CSZ matrix allows the application of this material as solid oxide fuel cell electrolytes, due to its better fracture toughness and ionic conductivity, compared to yttria-stabilized cubic zirconia ceramics. (author)

Garcia, Rafael Henrique Lazzari

2007-07-01

 
 
 
 
141

Summary Of 2009 Rheology Modifier Program  

International Nuclear Information System (INIS)

The overall objective of the EM-31 Rheological Modifiers and Wetting Agents program is to utilize commercially available rheology modifiers to increase the solids fraction of radioactive sludge based waste streams, resulting in an increase in throughput and decreasing the overall processing time. The program first investigates the impact of rheology modifiers on slurry simulants and then utilizes the most effective rheology modifiers on radioactive slurries. The work presented in this document covers the initial investigation of rheology modifier testing with simulants. This task is supported by both the Savannah River National Laboratory (SRNL) and Pacific Northwest National Laboratory (PNNL). The SRNL EM-31 task, for this year, was to investigate the use of rheology modifiers on simulant Defense Waste Processing Facility (DWPF) melter feeds. The task is to determine, based on the impact of the rheology modifier, if there are rheology modifiers that could reduce the water content of the slurry going to the DWPF melter, hence increasing the melt rate by decreasing the water loading. The rheology modifier in essence would allow a higher solids content slurry to have the same type of rheology or pumpability of a lower solids slurry. The modifiers selected in this report were determined based on previous modifiers used in high level waste melter feed simulants, on-going testing performed by counterparts at PNNL, and experiences gain through use of modifiers in other Department of Energy (DOE) processes such as grout processing. There were 12 rheology modifiers selected for testing, covering both organic and inorganic types and they were tested at four different concentrations for a given melter feed. Five different DWPF melter feeds were available and there was adequate material in one of the melter feeds to increase the solids concentration, resulting in a total of six simulants for testing. The mass of melter feed available in each simulant was not adequate for testing each rheology modifier, hence based on the changes in rheology for a given rheology modifier, rheology modifiers were either dropped or added between simulants. Three rheology modifiers were used on all simulants. The results from this testing indicate that citric acid or polycarboxylate based rheology modifiers are the most effective in reducing the yield stress, by as much as 70% at the higher rheology modifier additions and were effective on most of the tested simulants. These rheology modifiers are organic, hence the can also be used as reductants in melter operations. The most effective non-organic rheology modifiers, sodium metasilicate reduced the yield stress by 10%. It is recommended that both citric acid and commercially available polycarboxylate rheology modifiers be further investigated. Different molecular weight polycarboxylates and different types of polycarboxylates used in other industries must be considered. These polycarboxylates are extensively utilized in the cement, ceramic, and water treatment processes, hence readily available. Future work on DWPF melter feeds involving rheology modifiers should include, assuming the present method of processing sludge through DPWF does not change, is: (1) Investigate the use of polycarboxylate in various processes and procure polycarboxylates for testing. Limit rheology modifier selection and future testing between four and eight different types. (2) Test rheology modifiers on at least two different chemical types or bounding DWPF SME product simulants. Test to include the impact of boiling and the effectiveness in reducing water content via rheology versus weight percent curves. (3) Based on selected modifiers, perform testing on actual radioactive melter feed based on results from simulant testing.

142

SUMMARY OF 2009 RHEOLOGY MODIFIER PROGRAM  

Energy Technology Data Exchange (ETDEWEB)

The overall objective of the EM-31 Rheological Modifiers and Wetting Agents program is to utilize commercially available rheology modifiers to increase the solids fraction of radioactive sludge based waste streams, resulting in an increase in throughput and decreasing the overall processing time. The program first investigates the impact of rheology modifiers on slurry simulants and then utilizes the most effective rheology modifiers on radioactive slurries. The work presented in this document covers the initial investigation of rheology modifier testing with simulants. This task is supported by both the Savannah River National Laboratory (SRNL) and Pacific Northwest National Laboratory (PNNL). The SRNL EM-31 task, for this year, was to investigate the use of rheology modifiers on simulant Defense Waste Processing Facility (DWPF) melter feeds. The task is to determine, based on the impact of the rheology modifier, if there are rheology modifiers that could reduce the water content of the slurry going to the DWPF melter, hence increasing the melt rate by decreasing the water loading. The rheology modifier in essence would allow a higher solids content slurry to have the same type of rheology or pumpability of a lower solids slurry. The modifiers selected in this report were determined based on previous modifiers used in high level waste melter feed simulants, on-going testing performed by counterparts at PNNL, and experiences gain through use of modifiers in other Department of Energy (DOE) processes such as grout processing. There were 12 rheology modifiers selected for testing, covering both organic and inorganic types and they were tested at four different concentrations for a given melter feed. Five different DWPF melter feeds were available and there was adequate material in one of the melter feeds to increase the solids concentration, resulting in a total of six simulants for testing. The mass of melter feed available in each simulant was not adequate for testing each rheology modifier, hence based on the changes in rheology for a given rheology modifier, rheology modifiers were either dropped or added between simulants. Three rheology modifiers were used on all simulants. The results from this testing indicate that citric acid or polycarboxylate based rheology modifiers are the most effective in reducing the yield stress, by as much as 70% at the higher rheology modifier additions and were effective on most of the tested simulants. These rheology modifiers are organic, hence the can also be used as reductants in melter operations. The most effective non-organic rheology modifiers, sodium metasilicate reduced the yield stress by 10%. It is recommended that both citric acid and commercially available polycarboxylate rheology modifiers be further investigated. Different molecular weight polycarboxylates and different types of polycarboxylates used in other industries must be considered. These polycarboxylates are extensively utilized in the cement, ceramic, and water treatment processes, hence readily available. Future work on DWPF melter feeds involving rheology modifiers should include, assuming the present method of processing sludge through DPWF does not change, is: (1) Investigate the use of polycarboxylate in various processes and procure polycarboxylates for testing. Limit rheology modifier selection and future testing between four and eight different types. (2) Test rheology modifiers on at least two different chemical types or bounding DWPF SME product simulants. Test to include the impact of boiling and the effectiveness in reducing water content via rheology versus weight percent curves. (3) Based on selected modifiers, perform testing on actual radioactive melter feed based on results from simulant testing.

Hansen, E.

2009-12-08

143

Numerical Studies of Foam Rheology  

Science.gov (United States)

Most recent work on the rheology of foam has concentrated on the dry foam limit, where the gas volume fraction is nearly 1, the bubbles are polyhedral, and the liquid films, edges, and vertices between the bubbles are the relevant dynamical objects. A new model(D.J. Durian, to appear in Phys. Rev. Lett, Dec 95.) concentrates on the gas bubbles, rather than the liquid, and applies to the wet foam where the bubbles are more nearly spherical and the edges and vertices are not well defined. We present numerical simulations of this model, and show that it reproduces many of the rheological properties of foams. In particular, we examine the relation between inhomogeneous, intermittent microscopic bubble rearrangements and smooth macroscopic flow.

Langer, Stephen A.; Liu, Andrea J.; Durian, Douglas J.

1996-03-01

144

RHEOLOGICAL PROPERTIES OF MINERAL OIL  

Directory of Open Access Journals (Sweden)

Full Text Available In this article presents us rheological behavior of mineral oil. Apparent viscosity of mineral oil was determined at temperatures between 400C-900C and shear rates ranging from 3.3-120s-1. This study is to find a polynomial dependence on temperature and oil viscosity shear rate. Value of parameters of the theoretical models described by equations and correlation coefficient were determined by correlating a characteristic polynomial equation of each curve.

IOANA STANCIU

2011-12-01

145

Electrolytic cell and anode for brine electrolytes  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an electrolytic cell for the production of halogens or halates from their corresponding brine electrolytes, consisting essentially of: (a) an electrically conductive container for the electrolytes having a removable cover electrically insulated from a lower portion of the container; (b) an anode affixed to the cover and associated pairs of cathodes that are electrically connected to the lower portion of the container with the anode and cathodes being adapted to be operatively positioned within the container. At least a portion of the anode is overlapped by each adjacent cathode and the cathodes and anode are adapted to be immersed in the electrolytes. The anode consists essentially of: (i) a self supporting aluminum core, (ii) a sheath of metal from the titanium group completely covering at least that portion of the core that is disposed to be located within the interior of the container during cell operation, and (iii) an electroconductive coating of precious metal covering at least that portion of the anode and sheath that is overlapped by an adjacent cathode in (b); (c) means for applying a DC voltage between the anode and the lower portion of the container; (d) means for introducing brine electrolyte into the lower portion of the container, and (e) means for withdrawing from the container halogens or halates produced by electrolysis of the brine.

Hodges, J.R.

1987-04-14

146

Rheology of oil sands slurries  

Energy Technology Data Exchange (ETDEWEB)

This study focused on integrating rheology and colloid science to improve recovery of bitumen in surface mined oil sands. Factors that influence recovery, such as conditions of particle interaction, solids concentration and shear rate, were reviewed. In an effort to understand the rheological behaviour of clay-in-water suspensions, an elaborate procedure was developed to separate an inter-bedded clay layer from a site at Albian Sands Energy Inc. The variables were water chemistry, solids concentration, and shear rate. The research study was conducted at the Alberta Research Council with the support of the CONRAD Extraction Group. A controlled stress rheometer was used to provide the quantitative evaluations of the clay slurry properties. The research results indicate that the viscoelastic properties of the slurry are highly influenced by the shear history of the slurry, solids content, calcium concentration, and sample aging. Shear thinning behaviour was observed in all slurry samples, but the slurry viscosity increased with test time for a given shear rate. In order to classify the slurries, a method was developed to distinguish the gel strength. The slurries were then classified into 3 distinct patterns, including no gel, weak gel and strong gel. The evolution of the experimental protocols were described along with the current stability maps that correlate the domains of the gel strength according to the solids concentration, calcium ion content, and shear rate. It was concluded that the rheological properties of oil sands slurries influence bitumen recovery in commercial surface-mined oil sands operations. tabs., figs.

Chow, R.; Zhou, J. [Alberta Research Council, Edmonton, AB (Canada). Mineral Oil Sands Unit; Wallace, D. [Dean Wallace Consulting Inc., Beaumont, AB (Canada)

2006-07-01

147

Synthesis of yttria-doped zirconia anodes and calcium-doped ceria electrolyte to fuel cell; Sintese de anodos de zirconia dopada com itria e eletrolito de ceria dopada com calcia para celulas a combustivel  

Energy Technology Data Exchange (ETDEWEB)

From the pursuit of lower operating temperature of fuel cells solid oxide was used polymeric precursor for the synthesis of reactive powder compositions Zr{sub 0,92}Y{sub 0,08}O{sub 2} for the anode and Ce{sub 0,88}Ca{sub 0,12}O{sub 2} for the electrolyte. The solutions were prepared using the metal in much of the composition and citric acid molar ratio of 1:3, under stirring at 60 deg C/1 h. The mixture of metallic citrates was subjected to agitation at a temperature of 80 deg C which was added ethylene glycol in the ratio 60:40 by weight citric acid / ethylene glycol, to form a resin that was pre-calcined at 300 deg C/3 h for to form the expanded resin. The powders were disaggregated in a mortar, screened and calcined at 400, 600 and 800 deg C/2 h. The powders were characterized by standard X-ray diffraction. (author)

Almeida, G.R.S de; Fagury Neto, E.; Rabelo, A.A., E-mail: grs_gustavo@hotmail.co [Universidade Federal do Para (UFPA), Maraba, PA (Brazil). Fac. de Engenharia de Materiais

2010-07-01

148

Stabilized ?-BIMNVOX solid electrolyte: Ethylene glycol–citrate sol–gel synthesis, microwave-assisted calcination, and structural and electrical characterization  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •?-BIMNVOX was synthesized by ethylene glycol–citrate sol–gel route. •?-BIMNVOX crystallizes by 25-min microwave-assisted calcination. •Smaller particle sizes for microwave calcined BIMNVOX samples. •Best oxide-ion performance for microwave calcined BIMNVOX samples. -- Abstract: Samples of ?-BIMNVOX (Bi{sub 2}V{sub 1?x}Mn{sub x}O{sub 5.5?x/2}; 0.13 ? x ? 0.20) system were synthesized by an ethylene glycol–citrate sol–gel route. The resulting xerogels were then calcined by the microwave heating using a modified domestic microwave oven operated at 2.45 GHz. Microwave-assisted calcination samples in comparison with other conventionally calcined samples were characterized in terms of phase crystallization, stabilization and particle size using simultaneous thermogravimetric–differential thermal analysis (TG–DTA), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The AC impedance spectroscopy was employed for electrical characterization. It was found that the microwave-assisted calcination route successfully produces better crystalline stabilized ?-BIMNVOX samples with appreciably small average particle sizes after only 25 min of microwave heating. The electrical properties of microwave calcined ?-BIMNVOX system make it an advanced low-temperature solid electrolyte suitable for use in oxide-ion based electrochemical applications.

Al-Areqi, Niyazi A.S., E-mail: niyazi.alareqi@gmail.com [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Beg, Saba [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Al-Alas, Ahlam [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Hafeez, Shehla [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India)

2013-12-25

149

Gel-combustion synthesis of LiFePO4/C composite with improved capacity retention in aerated aqueous electrolyte solution  

International Nuclear Information System (INIS)

Highlights: ? Gel combustion route was used to prepare LiFePO4/C composite with high carbon content ? Theoretical discharge capacity was achieved in non-aqueous medium at rate 0.1 C ? Best so far reported capacity retention in aqueous electrolyte was achieved ? Thick C shell seems to be of crucial importance for LiFePO4 in aqueous media. -- Abstract: The LiFePO4/C composite containing 13.4 wt.% of carbon was synthesized by combustion of a metal salt–(glycine + malonic acid) gel, followed by an isothermal heat-treatment of combustion product at 750 °C in reducing atmosphere. By a brief test in 1 M LiClO4–propylene carbonate solution at a rate of C/10, the discharge capacity was proven to be equal to the theoretical one. In aqueous LiNO3 solution equilibrated with air, at a rate C/3, initial discharge capacity of 106 mAh g?1 was measured, being among the highest ones observed for various Li-ion intercalation materials in aqueous solutions. In addition, significant prolongation of cycle life was achieved, illustrated by the fact that upon 120 charging/discharging cycles at various rates, the capacity remained as high as 80% of initial value. The chemical diffusion coefficient of lithium in this composite was measured by cyclic voltammetry. The obtained values were compared to the existing literature data, and the reasons of high scatter of reported values were considered

150

Stabilized ?-BIMNVOX solid electrolyte: Ethylene glycol–citrate sol–gel synthesis, microwave-assisted calcination, and structural and electrical characterization  

International Nuclear Information System (INIS)

Highlights: •?-BIMNVOX was synthesized by ethylene glycol–citrate sol–gel route. •?-BIMNVOX crystallizes by 25-min microwave-assisted calcination. •Smaller particle sizes for microwave calcined BIMNVOX samples. •Best oxide-ion performance for microwave calcined BIMNVOX samples. -- Abstract: Samples of ?-BIMNVOX (Bi2V1?xMnxO5.5?x/2; 0.13 ? x ? 0.20) system were synthesized by an ethylene glycol–citrate sol–gel route. The resulting xerogels were then calcined by the microwave heating using a modified domestic microwave oven operated at 2.45 GHz. Microwave-assisted calcination samples in comparison with other conventionally calcined samples were characterized in terms of phase crystallization, stabilization and particle size using simultaneous thermogravimetric–differential thermal analysis (TG–DTA), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The AC impedance spectroscopy was employed for electrical characterization. It was found that the microwave-assisted calcination route successfully produces better crystalline stabilized ?-BIMNVOX samples with appreciably small average particle sizes after only 25 min of microwave heating. The electrical properties of microwave calcined ?-BIMNVOX system make it an advanced low-temperature solid electrolyte suitable for use in oxide-ion based electrochemical applications

151

Anesthetics and red blood cell rheology  

Science.gov (United States)

There are many conditions where it is useful for anesthetists to have a knowledge of blood rheology. Blood rheology plays an important role in numerous clinical situations. Hemorheologic changes may significantly affect the induction and recovery times with anesthetic agents. But also, hemorheologic factors are directly or indirectly affected by many anesthetic agents or their metabolites. In this review, the blood rheology with special emphasis on its application in anesthesiology, the importance hemorheological parameters in anesthesiology and also the effect of some anesthetic substances on red blood cell rheology were presented.

Aydogan, Burcu; Aydogan, Sami

2014-05-01

152

Electrolytes based on alkoxysilyl-functionalized ionic liquids: viscoelastic properties and conductivity.  

Science.gov (United States)

Ionic liquids can be successfully used as electrolytes in electrochemical devices when they are in their quasi-solid state. Among several methods of solidification, a sol-gel process was chosen and a set of alkoxysilyl-functionalized iodide imidazolium-based ionic liquids were synthesized. The electrolytes were prepared by mixing these ionic liquids with a non-polymerisable ionic liquid (1-methyl-3-propylimidazolium iodide (MPIm(+)I(-))). Iodine was dissolved in an electrolyte matrix in order to form an I3(-)/I(-) redox couple. The change of the structure from sol to gel was followed by rheological tests in order to show the effect of different rheological parameters on the gelation process. The solvolysis with glacial acetic acid and condensation were followed by rheological experiments on the samples taken from a batch, and in situ on the rheometer. The formed three-dimensional sol-gel networks of various alkoxysilyl-functionalized ionic liquids differed in their microstructures and viscoelastic properties that were correlated with conductivity. The results show that the conductivity of approximately 10(-3) S cm(-1) at room temperature was achieved for the gels with relatively high values of elastic modulus and noticeable viscous contribution. It is shown that not only the viscosity but also the viscoelastic behavior and especially the relationship between viscous and elastic moduli (phase shift) together with the time of gelation are essential for the high conductivity of electrolytes. PMID:24955729

Slemenik Perše, L; Colovi?, M; Hajzeri, M; Orel, B; Surca Vuk, A

2014-08-14

153

Chocolate rheology / Reologia de chocolate  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Reologia é a ciência que estuda a deformação e fluxo de sólidos e fluidos sob a influência de forças mecânicas. As determinações reológicas de um produto no estágio de produção podem ser úteis no controle de qualidade. A microestrutura de um produto pode ser correlacionada com o comportamento reológ [...] ico, permitindo desenvolver novos materiais. A reometria permite a aplicação de equações reológicas em processos de engenharia, particularmente nas operações unitárias que envolvem aquecimento e transferência de massa. A demanda dos consumidores torna possível obter um produto que esteja de acordo com as necessidades. As indústrias de chocolates trabalham com o produto na fase líquida na concha, na temperadeira e também durante o bombeamento. O desenho de cada tipo de equipamento é essencial para o ótimo processamento. No desenho de cada processo é necessário conhecer as características físicas do produto. O comportamento reológico do chocolate pode auxiliar no conhecimento das características de aplicação e dos consumidores do produto. Alimentos estão geralmente em estado metaestável. Sua textura depende das trocas estruturais que ocorrem com seu processamento. Chocolate líquido é uma suspensão com propriedades que são fortemente afetadas pelas características das partículas, incluindo não somente partículas dispersas mas também cristais de gordura formados durante o resfriamento e solidificação. A reologia de chocolates é extensivamente estudada, a textura do chocolate e sua estabilidade são fortemente afetadas pela presença de cristais específicos Abstract in english Rheology is the science that studies the deformation and flow of solids and fluids under the influence of mechanical forces. The rheological measures of a product in the stage of manufacture can be useful in quality control. The microstructure of a product can also be correlated with its rheological [...] behavior allowing for the development of new materials. Rheometry permits attainment of rheological equations applied in process engineering, particularly unit operations that involve heat and mass transfer. Consumer demands make it possible to obtain a product that complies with these requirements. Chocolate industries work with products in a liquid phase in conching, tempering, and also during pumping operations. A good design of each type of equipment is essential for optimum processing. In the design of every process, it is necessary to know the physical characteristics of the product. The rheological behavior of chocolate can help to know the characteristics of application of the product and its consumers. Foods are generally in a metastable state. Their texture depends on the structural changes that occur during processing. Molten chocolate is a suspension with properties that are strongly affected by particle characteristics including not only the dispersed particles but also the fat crystals formed during chocolate cooling and solidification. Chocolate rheology is extensively studied, and it is known that chocolate texture and stability is strongly affected by the presence of specific crystals

Estela Vidal, Gonçalves; Suzana Caetano da Silva, Lannes.

154

Chocolate rheology / Reologia de chocolate  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Reologia é a ciência que estuda a deformação e fluxo de sólidos e fluidos sob a influência de forças mecânicas. As determinações reológicas de um produto no estágio de produção podem ser úteis no controle de qualidade. A microestrutura de um produto pode ser correlacionada com o comportamento reológ [...] ico, permitindo desenvolver novos materiais. A reometria permite a aplicação de equações reológicas em processos de engenharia, particularmente nas operações unitárias que envolvem aquecimento e transferência de massa. A demanda dos consumidores torna possível obter um produto que esteja de acordo com as necessidades. As indústrias de chocolates trabalham com o produto na fase líquida na concha, na temperadeira e também durante o bombeamento. O desenho de cada tipo de equipamento é essencial para o ótimo processamento. No desenho de cada processo é necessário conhecer as características físicas do produto. O comportamento reológico do chocolate pode auxiliar no conhecimento das características de aplicação e dos consumidores do produto. Alimentos estão geralmente em estado metaestável. Sua textura depende das trocas estruturais que ocorrem com seu processamento. Chocolate líquido é uma suspensão com propriedades que são fortemente afetadas pelas características das partículas, incluindo não somente partículas dispersas mas também cristais de gordura formados durante o resfriamento e solidificação. A reologia de chocolates é extensivamente estudada, a textura do chocolate e sua estabilidade são fortemente afetadas pela presença de cristais específicos Abstract in english Rheology is the science that studies the deformation and flow of solids and fluids under the influence of mechanical forces. The rheological measures of a product in the stage of manufacture can be useful in quality control. The microstructure of a product can also be correlated with its rheological [...] behavior allowing for the development of new materials. Rheometry permits attainment of rheological equations applied in process engineering, particularly unit operations that involve heat and mass transfer. Consumer demands make it possible to obtain a product that complies with these requirements. Chocolate industries work with products in a liquid phase in conching, tempering, and also during pumping operations. A good design of each type of equipment is essential for optimum processing. In the design of every process, it is necessary to know the physical characteristics of the product. The rheological behavior of chocolate can help to know the characteristics of application of the product and its consumers. Foods are generally in a metastable state. Their texture depends on the structural changes that occur during processing. Molten chocolate is a suspension with properties that are strongly affected by particle characteristics including not only the dispersed particles but also the fat crystals formed during chocolate cooling and solidification. Chocolate rheology is extensively studied, and it is known that chocolate texture and stability is strongly affected by the presence of specific crystals

Estela Vidal, Gonçalves; Suzana Caetano da Silva, Lannes.

2010-12-01

155

Rheology and stability of water-in-oil-in-water multiple emulsions containing Span 83 and Tween 80  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Multiple emulsions are often stabilized using a combination of hydrophilic and hydrophobic surfactants. The ratio of these surfactants is important in achieving stable multiple emulsions. The objective of this study was to evaluate the long-term stability of water-in-oil-in-water (W/O/W) multiple emulsions with respect to the concentrations of Span 83 and Tween 80. In addition, the effect of surfactant and electrolyte concentration on emulsion bulk rheological properties was investigated. Lig...

Jiao, Jim; Burgess, Diane J.

2003-01-01

156

Rheology of unstable mineral emulsions  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the rheology of mineral oils and their unstable water emulsion were investigated. The oil samples were domestic crude oil UA, its fractions UA1, UA4 and blend semi-product UP1, while the concentration of oil in water emulsions was in the range from 1 up to 30%. The results were analyzed based on shear stress. The oil samples UA, UA1 and UP1 are Newtonian fluids, while UA4 is pseudoplastic fluid. The samples UA and UA4 show higher value of shear stress (83.75 Pa, 297 Pa, then other two samples UA1 and UP1 (18.41 Pa, 17.52 Pa. Rheology of investigated oils due to its complex chemical composition should be analyzed as a simultaneous effect of all their components. Therefore, structural composition of the oils was determined, namely content of paraffins, naphthenes, aromatics and asphaltenes. All samples contain paraffins, naphthenes and aromatics but only oils UA and UA4 contain asphaltenes as well. All investigated emulsions except 30% EUA4 are Newtonian fluids. The EUA4 30% emulsion shows pseudoplastic behaviour, and it is the only 30% emulsion among investigated ones that achieves lower shear stress then its oil. The characteristics of oil samples that could have an influence on their properties and their emulsion rheology, were determined. These characteristics are: neutralization number, interfacial tension, dielectric constant, and emulsivity. Oil samples UA and UA4 have significantly higher values of neutralization number, dielectric constants, and emulsivity. The sample UA has the lowest value of interface tension and the greatest emulsivity, indicating that this oil, among all investigated, has the highest preference for building emulsion. This could be the reason why 20% and 30% emulsions of the oil UA achieve the highest shear stress among all investigated emulsions.

Sokolovi? Dunja S.

2013-01-01

157

Rheology of coal slurries. 1; Sekitan slurry no rheology  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes rheological characteristics of coal slurries. Steady state models for coal slurries include the index law model, the Bingham model including yield stress in high shear velocity regions, and the Herschel-Bulkley model for the case of nonlinearity in regions higher than the yield stress. The Casson model is used to express nonlinearity and yield stress in slurry flows in middle to low shear velocity regions. While parameters for the models have been determined experimentally, discussions are given in the field of rheology on methods to forecast flow characteristics from slurry adjustment parameters. These methods may include the Einstein expression, the Guth-Simha expression, the Thomas forecasting expression, and the Happel`s cell model. The Mooney expression and the Roscoe expression are the semi-empirical expressions that can be applied to coagulation systems. Slurry preparation importantly requires high coal concentration and fluidity. For this requirement, an expression for the optimum grain size distribution has been proposed. This expression provides a volumetric rate for filling largest particles when a grain size distribution range is limited. The larger the rate, the freedom of movements of solid particles becomes larger. 18 refs., 4 figs.

Usui, H. [Yamaguchi University, Yamaguchi (Japan)

1995-09-20

158

Facile Synthesis of Porous Metal Oxide Nanotubes and Modified Nafion Composite Membranes for Polymer Electrolyte Fuel Cells Operated under Low Relative Humidity.  

Science.gov (United States)

We describe a facile route to fabricate mesoporous metal oxide (TiO2, CeO2 and ZrO1.95) nanotubes for efficient water retention and migration in a Nafion membrane operated in polymer electrolyte fuel cell under low relative humidity (RH). Porous TiO2 nanotubes (TNT), CeO2 nanotubes (CeNT), and ZrO1.95 (ZrNT) were synthesized by calcining electrospun polyacrylonitrile nanofibers embedded with metal precursors. The nanofibers were prepared using a conventional single spinneret electrospinning technique under an ambient atmosphere. Their porous tubular morphology was observed by SEM and TEM analyses. HR-TEM results revealed a porous metal oxide wall composed of small particles joined together. The mesoporous structure of the samples was analyzed using BET. The tubular morphology and outstanding water absorption ability of the TNT, CeNT, and ZrNT fillers resulted in the effective enhancement of proton conductivity of Nafion composite membranes under both fully humid and dry conditions. Compared to a commercial membrane (Nafion, NRE-212) operated under 100% RH at 80 °C, the Nafion-TNT composite membrane delivered approximately 1.29 times higher current density at 0.6 V. Compared to the Nafion-TiO2 nanoparticles membrane, the Nafion-TNT membrane also generated higher current density at 0.6 V. Additionally, compared to a NRE-212 membrane operated under 50% RH at 80 °C, the Nafion-TNT composite membrane exhibited 3.48 times higher current density at 0.6 V. Under dry conditions (18% RH at 80 °C), the Nafion-TNT, Nafion-CeNT, and Nafion-ZrNT composite membranes exhibited 3.4, 2.4, and 2.9 times higher maximum power density, respectively, than the NRE-212 membrane. The remarkably high performance of the Nafion composite membrane was mainly attributed to the reduction of ohmic resistance by the mesoporous hygroscopic metal oxide nanotubes, which can retain water and effectively enhance water diffusion through the membrane. PMID:25203667

Ketpang, Kriangsak; Lee, Kibong; Shanmugam, Sangaraju

2014-10-01

159

Rheology of Soft Glassy Materials  

CERN Document Server

We attribute similarities in the rheology of many soft materials (foams, emulsions, slurries, etc.) to the shared features of structural disorder and metastability. A generic model for the mesoscopic dynamics of ``soft glassy matter'' is introduced, with interactions represented by a mean-field noise temperature x. We find power law fluid behavior either with (x<1) or without (1

Sollich, P; Hébraud, P; Cates, M E; Sollich, Peter; Lequeux, Francois; Hebraud, Pascal; Cates, Michael E

1997-01-01

160

Laboratory Exercise: What Controls Rheology?  

Science.gov (United States)

A short laboratory exercise, conducted by students, is used to illustrate the multiple factors that contribute to rocks' varied responses to deformation. Analogue materials (play-doh, notebook springs, butter, silly putty, plastic bags, etc.) are used to illustrate many of the controlling factors such as lithology, stress, temperature, confining pressure, strain rate, preexisting weaknesses, and accumulated strain. The analogue experiments are presented in conjunction with parallel data from deformation experiments and field studies. The tandem presentation of analogue experiment and real data requires the students to obtain a natural "feel" for rheologic parameters and more exhaustively analyze the important conclusions obtained from field and deformation experiment data.

Czeck, Dyanna

 
 
 
 
161

Electrolytic cell stack with molten electrolyte migration control  

Science.gov (United States)

An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate.

Kunz, H. Russell (Vernon, CT); Guthrie, Robin J. (East Hartford, CT); Katz, Murray (Newington, CT)

1988-08-02

162

Electrochemically stable electrolytes  

Science.gov (United States)

This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes. 16 figs.

Angell, C.A.; Zhang, S.S.; Xu, K.

1999-01-05

163

Stable electrolytes for lithium batteries  

Science.gov (United States)

The physical and chemical properties of organic electrolytes for lithium batteries, and the factors affecting their conductivity, are discussed. In particular, attention is focussed on the modification of the solvent structure, organic electrolytes based on sulfolane or dimethyl sulfoxide, the addition effect of special organic compounds into the electrolyte, and some characteristics of miscellaneous electrolytes.

Matsuda, Y.

164

Blood rheology in marine mammals  

Directory of Open Access Journals (Sweden)

Full Text Available The field of blood oxygen transport and delivery to tissues has been studied by comparative physiologists for many decades. Within this general area, the particular differences in oxygen delivery between marine and terrestrial mammals has focused mainly on oxygen supply differences and delivery to the tissues under low blood flow diving conditions. Yet, the study of the inherent flow properties of the blood itself (hemorheology is rarely discussed when addressing diving. However, hemorheology is important to the study of marine mammals because of the critical nature of the oxygen stores that are carried in the blood during diving periods. This review focuses on the essential elements of hemorheology, how they are defined and on fundamental rheological applications to marine mammals. While the comparative rationale used throughout the review is much broader than the particular problems associated with diving, the basic concepts focus on how changes in the flow properties of whole blood would be critical to oxygen delivery during diving. This review introduces the reader to most of the major rheological concepts that are relevant to the unique and unusual aspects of the diving physiology of marine mammals.

OguzBaskurt

2010-12-01

165

Rheological behaviour of reconstructed skin.  

Science.gov (United States)

Reconstructed skins have been developed to replace skin when the integrity of tissue has been compromised following severe injury, and to provide alternative methods validating the innocuousness and effectiveness of dermatological and cosmetic products. However the functional properties of tissue substitutes have not been well characterised, mainly since mechanical measurement devices have not been designed to test cell culture materials in vitro. From the mechanical standpoint, reconstructed skin is a heterogeneous multi-layer viscoelastic material. To characterise the time-dependent behaviour of reconstructed skin, spherical indentation load-relaxation tests were performed with a specific original device adapted to measure small soft tissue samples. Load-relaxation indentation tests were performed on a standard reconstructed skin model and on sub-components of the reconstructed skin (3D-scaffold alone and dermal equivalent). Generalised Maxwell and Kelvin-Voigt rheological models are proposed for analysing the mechanical behaviour of each biological tissue. The results indicated a modification of the rheological behaviour of the samples tested as a function of their biological structure. The 3D-scaffold was modelled using the one-branch Maxwell model, while the dermis equivalent and the reconstructed skin were modeled using a one-branch and a two-branch Kelvin-Voigt model, respectively. Finally, we demonstrated that skin cells contribute to global mechanical behaviour through an increase of the instantaneous relaxation function, while the 3D-scaffold alone influences the mechanical response of long relaxation times. PMID:24956159

Pailler-Mattei, C; Laquièze, L; Debret, R; Tupin, S; Aimond, G; Sommer, P; Zahouani, H

2014-09-01

166

Microgravity Foam Structure and Rheology  

Science.gov (United States)

To exploit rheological and multiple-light scattering techniques, and ultimately microgravity conditions, in order to quantify and elucidate the unusual elastic character of foams in terms of their underlying microscopic structure and dynamics. Special interest is in determining how this elastic character vanishes, i.e. how the foam melts into a simple viscous liquid, as a function of both increasing liquid content and shear strain rate. The unusual elastic character of foams will be quantified macroscopically by measurement of the shear stress as a function of static shear strain, shear strain rate, and time following a step strain; such data will be analyzed in terms of a yield stress, a static shear modulus, and dynamical time scales. Microscopic information about bubble packing and rearrangement dynamics, from which these macroscopic non-Newtonian properties presumably arise, will be obtained non-invasively by novel multiple-light scattering diagnostics such as Diffusing-Wave Spectroscopy (DWS). Quantitative trends with materials parameters, such as average bubble size, and liquid content, will be sought in order to elucidate the fundamental connection between the microscopic structure and dynamics and the macroscopic rheology.

Durian, Douglas J.

1997-01-01

167

Nonlinear rheology of colloidal dispersions  

International Nuclear Information System (INIS)

Colloidal dispersions are commonly encountered in everyday life and represent an important class of complex fluid. Of particular significance for many commercial products and industrial processes is the ability to control and manipulate the macroscopic flow response of a dispersion by tuning the microscopic interactions between the constituents. An important step towards attaining this goal is the development of robust theoretical methods for predicting from first-principles the rheology and nonequilibrium microstructure of well defined model systems subject to external flow. In this review we give an overview of some promising theoretical approaches and the phenomena they seek to describe, focusing, for simplicity, on systems for which the colloidal particles interact via strongly repulsive, spherically symmetric interactions. In presenting the various theories, we will consider first low volume fraction systems, for which a number of exact results may be derived, before moving on to consider the intermediate and high volume fraction states which present both the most interesting physics and the most demanding technical challenges. In the high volume fraction regime particular emphasis will be given to the rheology of dynamically arrested states. (topical review)

168

Synthesis of fuel cell grade Bi{sub 2}Co{sub 0.1}V{sub 0.9}O{sub 5.35} solid electrolyte thin films  

Energy Technology Data Exchange (ETDEWEB)

Oxygen ion conducting solid electrolyte thin film of BIMEVOX family Bi{sub 2}Co{sub 0.1}V{sub 0.9}O{sub 5.35} was synthesized by an innovative and cost effective spray pyrolysis technique on alumina substrate. The uniformity in deposition is obtained by propane-2ol assisted atomization. Thermal decomposition behavior of precursors was studied using thermogravimetric analysis (TGA and DTA). The room temperature stabilized pure {gamma}-phase Bi{sub 2}Co{sub 0.1}V{sub 0.9}O{sub 5.35} was obtained by annealing films at 750 deg. C. The phase of the material is confirmed by XRD. The morphological studies were done using SEM. DC electrical conductivity measurements were done with respect to temperature to reveal the onset for ionic conduction and it was found to be about 420 deg. C. The AC conductivity measurements were also done using impedance spectroscopy in the frequency range 100 Hz to 1 MHz and in temperature range 228-550 deg. C. The ionic conductivity was found to be increasing with temperature. It was of the order of 21.16 S m{sup -1} at 550 deg. C. The single semicircular complex impedance plot shows that the ionic conduction is through grain interior hopping mechanism. The activation energy in high-temperature region was found to be 0.36 eV which is lower than other methods of synthesis. Which is very much favorable for usage of these films in low-temperature solid oxide fuel cells.

Joshi, R.S.; Nimat, R.K. [Department of Physics, Shivaji University, Vidyanagar, Kolhapur 416004, Maharashtra (India); Pawar, S.H. [Department of Physics, Shivaji University, Vidyanagar, Kolhapur 416004, Maharashtra (India); Department of technology, D.Y. Patil University, Kolhapur 416006, Maharashtra (India)], E-mail: pawar_s_h@yahoo.co.in

2009-03-05

169

Equation for Electrolyte Viscosity  

Science.gov (United States)

Equation agrees with measurements over wide concentration range. Plot of calculated values from equation and measured values show close match except at extremely low concentrations of electrolyte. Other equations do not match data as well and limited to dilute solutions.

Fedors, R. F.

1985-01-01

170

Electrolytic oxidation of anthracite  

Science.gov (United States)

An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

Senftle, F. E.; Patton, K. M.; Heard, Jr. , I.

1981-01-01

171

High efficiency solid state dye sensitized solar cells with graphene-polyethylene oxide composite electrolytes  

Science.gov (United States)

Novel and highly effective composite electrolytes were prepared by combining the two dimensional graphene (Gra) and polyethylene oxide (PEO) for the solid electrolyte of dye sensitized solar cells (DSSCs). Gra sheets were uniformly coated by the polymer layer through the ester carboxylate bonding between oxygenated species on Gra sheets and PEO. The Gra-PEO composite electrolyte showed the large scale generation of iodide ions in a redox couple. From rheological analysis, the decrease in viscosity after the addition of LiI and I2 in the Gra-PEO electrolyte might be explained by the dipolar interactions being severely disrupted by the ionic interactions of Li+, I-, and I3- ions. A composite electrolyte with 0.5 wt% Gra presented a higher ionic conductivity (3.32 mS cm-1) than those of PEO and other composite electrolytes at room temperature. A high overall conversion efficiency (~5.23%) with a very high short circuit current (JSC) of 18.32 mA cm-2, open circuit voltage (VOC) of 0.592 V and fill factor (FF) of 0.48 was achieved in DSSCs fabricated with the 0.5 wt% Gra-PEO composite electrolyte. This enhanced photovoltaic performance might be attributed to the large scale formation of iodide ions in the redox electrolyte and the relatively high ionic conductivity.

Akhtar, M. Shaheer; Kwon, Soonji; Stadler, Florian J.; Yang, O. Bong

2013-05-01

172

Nuclear electrolytic hydrogen  

International Nuclear Information System (INIS)

An extensive study of hydrogen supply has recently been carried out by Ontario Hydro which indicates that electrolytic hydrogen produced from nuclear electricity could offer the lowest cost option for any future large scale hydrogen supply in the Province of Ontario, Canada. This paper provides a synopsis of the Ontario Hydro study, a brief overview of the economic factors supporting the study conclusion and discussion of a number of issues concerning the supply of electrolytic hydrogen by electric power utilities

173

Rheologycal properties of sodium carboxymethylcellulose in the presence of electrolyte and mixed micelle of surfactants  

Directory of Open Access Journals (Sweden)

Full Text Available One of the most significant aspects of polymer-surfactant interaction, from the practical point of view, is that of rheology control and viscosity enhancement. In the oppositely charged polyelectrolyte-surfactant system strong ionic interaction often leads to precipitation of the formed complex yielding serious problems. In this paper the interaction between anionic polyelectrolyte - sodium carboxymethylcellulose (NaCMC and cationic surfactant - cethyltrimethylammonium bromide (CTMAB has been investigated by rheological measurements. Addition of electrolyte NaBr and nonionic surfactant - Tween 80 reduced the binding strength, prevented the precipitation of the complex and increased the viscosity of the system. It was found that rheological properties are strong influenced by NaCMC-CTMAB interaction and the system exhibits either pseudoplastic or thixotropic or rheopectic behavior according to the intensity of interaction.

Sovilj Verica J.

2003-01-01

174

Possibilities of applying rheological measurements in metallurgy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of this paper is to analyse from the literature point of view the issues concerning modern methods of measuring the viscosity of liquid steel and solid-liquid steel in the course of rheological research with the use of a high temperature rheometer. The paper reviews the subject of measuring and modelling the viscosity value of steel with the use of equations and data available in the literature. It also presents the difficulties connected to rheological measurements of liquid steel and metallurgical slag.Design/methodology/approach: The main purpose of this paper is to present the issues relating to rheological measurements and the possibilities of their application in metallurgy.Findings: The paper describes the issues pertaining to the viscosity measurements of liquid and metallurgical slag.Research limitations/implications: In the future the authors are planning to develop an empirical model which would include rheological parameters and would be used to calculate the viscosity of liquid iron solutions on the basis of conducted rheological measurements of liquid steel.Practical implications: The results of investigation might be used in the future in semi-solid metal (SSM forming. A fundamental and detailed understanding of the steel rheology is crucial for industrialization.Originality/value: The paper presents the issues connected to the subject of and difficulties encountered in the course of rheological measurements of liquid ferroalloys and metallurgical slag.

M. Korolczuk-Hejnak

2012-12-01

175

Rheology  

Science.gov (United States)

The properties of a rheid represent essentially all Earth materials: they behave elastically over short time scales and plastically over long time scales. In this demonstration, silly putty is used to help explain these properties as well as the yield strength of a material.

Barker, Jeffrey

176

Thermodynamics of Electrolyte Solutions.  

Science.gov (United States)

Thermodynamics of electrolyte solutions has been studied and a new equation of state for mixtures containing electrolytes has been derived using perturbation theory. In this equation, short-range interactions between molecules are calculated using the Perturbed-Anisotropic-Chain theory (PACT) of Vimalchand and Donohue. A perturbation expansion based on Henderson's restricted primitive model is used for charge-charge interactions among ions. Solvation effects caused by charge-molecule interactions very near ions are taken into account through an effective dielectric constant. Additional new expressions, a third-order perturbation expansion for charge-dipole interactions and a first-order perturbation expansion for charge-induced dipole interactions, were derived for interactions of ions with molecules in the bulk of solution. This equation of state contains four parameters: s, number of segments per particle, q, normalized surface area per particle, epsilon, a characteristic energy per unit external surface area of a particle, and c, one-third number of external degree of freedom. For neutral molecules, these parameters have been determined using PACT by fitting simultaneously experimental vapor -pressure and liquid-density data. For ions, the parameters are calculated using literature values for polarizability and ionic radius which are adjusted by an ionic size parameter, C_{s}. In this work, preliminary calculations involving mean ionic activity coefficients for fifty strong electrolytes in water, specific volumes of several strong aqueous solutions, K factors for argon and methane in aqueous solutions of NaCl and aqueous solutions of KOH and vapor-liquid equilibra for aqueous solutions containing volatile weak electrolytes are carried out. The results show the usefulness of this new equation of state. In these caulations, the ionic size parameter, C_{s}, is the only adjustable parameter used for strong electrolytes over a range of molarity form infinite dilution to 6 molal. The calculations involving weak electrolytes here are carried out without using any adjustable mixture parameter. Average absolute errors are less than 5% for activity coefficients of most strong electrolytes in water, 1.5% for specific volumes for the two electrolyte systems tested, 5% for partial pressures of weak electrolytes in water, and 5% for K factors for the ternary systems containing strong electrolytes.

Jin, Gang

1989-12-01

177

Rheology of welding: experimental constraints  

Science.gov (United States)

The rheological behavior of pyroclastic deposits during welding is incompletely understood and is based on a surprisingly small number of experimental studies. Previous pioneering experimental studies were done on small (1 cm thick) samples of ash/crystal mixtures under constant load. They established minimum welding temperatures between 600 and 700^oC under loads of 0.7 MPa (˜40 m of ignimbrite) to 3.6 MPa (˜250 m depth of ignimbrite). However, these data are neither sufficiently comprehensive nor coherent enough to fully describe the rheology of pyroclastic mixtures. In addition, previous studies did not examine the microstructural and geometric changes associated with welding compaction. Our goal is to provide accurate and comprehensive constitutive relationships between material properties, temperature, load and strain rate for pyroclastic material undergoing welding. Here we present results from a newly designed experimental apparatus. The experimental apparatus consists of a LoadTrac II fully automated uniaxial compression load frame manufactured by Geocomp Corporation. The load frame has a built in displacement transducer and can run both constant strain rate (10-6 to 0.25 cm/s) and constant load (up to 1150 kg) tests to a maximum displacement of 7.5 cm. The sample assembly comprises 5 cm diameter cylindrical upper and lower pistons (insulating ceramic with steel conductive ends) housed in a copper jacket. Samples are 5 cm diameter cores and can vary in length from 1 to 15 cm depending on experimental needs. A fiber insulated tube furnace capable of reaching temperatures ?1000^oC surrounds the sample assembly. Temperature is measured using a thermocouple located inside the sample through the bottom piston; the furnace controller is capable of maintaining temperature fluctuations to soda-lime glass beads and rhyolitic volcanic ash, as well as, cores of pumiceous rhyodacite. Experimental runs use strain rates of 10-4 and 10-5 cm/s and loads of ˜0 to 4.5 MPa. Experiments are run at temperatures between 400 and 850^oC corresponding to below and above the calorimetric glass transition temperatures of the respective materials. Data deriving from constant load and constant strain rate experiments are being used to constrain rheological models for welding of pyroclastic material.

Quane, S. L.; Russell, J. K.; Kennedy, L. A.

2003-04-01

178

Experimental investigation on the rheology of foams  

Energy Technology Data Exchange (ETDEWEB)

The rheology of foams was investigated using aqueous and gelled foams and employing a pipe-type viscometer. Surfactant at 0.5 per cent concentration was used as the foaming agent. Results indicated that foam fluid rheology can be adequately characterized by the Herschel-Bulkley model. The experimental data served as the starting point for the development of new empirical correlations to predict foam fluid apparent viscosity. The use of these new correlations is expected to provide more accurate estimates of foam fluid rheological properties. 14 refs., 5 tabs., 14 figs.

Bonilla, L. F. [Univ. Surcolombiana, Neiva, Huila (Colombia); Shah, S. N. [Oklahoma Univ., Norman, OK (United States)

2000-07-01

179

Rheology of glasses containing crystalline material  

International Nuclear Information System (INIS)

The rheology of nonhomogeneous glassy melts that contain crystalline material has not been studied in much detail. In this study, the rheology of melts containing simulated nuclear waste has been characterized as a function of melt temperature and crystalline content. These melts can be either Newtonian or non-Newtonian fluids, depending on their crystalline contents. Melts which are free of crystals are strictly Newtonian. Melts which contain from 2 to 10 vol % crystals are Newtonian fluids, which obey the Einstein-Smoluchovsky equation. The rheology of the melts containing ? 13 vol % is complex, but can be explained in terms of absolute rate theory

180

Granular rheology in zero gravity  

International Nuclear Information System (INIS)

We present an experimental investigation on the rheological behaviour of model granular media made of nearly elastic spherical particles. The experiments are performed in a cylindrical Couette geometry and the experimental device is placed inside an aeroplane undergoing parabolic flights to cancel the effect of gravity. The corresponding curves, shear stress versus shear rate, are presented, and a comparison with existing theories is proposed. The quadratic dependence on the shear rate is clearly shown, and the behaviour as a function of the solid volume fraction of particles exhibits a power law function. It is shown that theoretical predictions overestimate the experimental results. We observe, at intermediate volume fractions, the formation of rings of particles regularly spaced along the height of the cell. The differences observed between experimental results and theoretical predictions are discussed and related to the structures formed in the granular medium submitted to the external shear

 
 
 
 
181

Active rheology of phospholipid vesicles  

Science.gov (United States)

Optical tweezers are used to manipulate the shape of artificial dioleoyl-phosphatidylcholine (DOPC) phospholipid vesicles of around 30?m diameter. Using a time-shared trapping system, a complex of traps drives oscillations of the vesicle equator, with a sinusoidal time dependence and over a range of spatial and temporal frequencies. The mechanical response of the vesicle membrane as a function of the frequency and wavelength of the driving oscillation is monitored. A simple model of the vesicles as spherical elastic membranes immersed in a Newtonian fluid, driven by a harmonic trapping potential, describes the experimental data. The bending modulus of the membrane is recovered. The method has potential for future investigation of nonthermally driven systems, where comparison of active and passive rheology can help to distinguish nonthermal forces from equilibrium fluctuations.

Brown, Aidan T.; Kotar, Jurij; Cicuta, Pietro

2011-08-01

182

Rheology of tetraphenylborate precipitate slurry  

International Nuclear Information System (INIS)

Savannah River Plant (SRP) is the nation's primary source of nuclear materials for defense, space, medical, and energy applications. SRP was built in the early 1950's by the Du Pont Company for the U.S. Atomic Energy Commission. The Du Pont Company still operates the plant as prime contractor for the U.S. Department of Energy. Since plant startup, approximately 72 million gallons of radioactive waste have been generated. Approximately 10% of the waste is sludge, which contains most of the radionuclides. The rest of the waste is liquid and salt, which consists primarily of sodium nitrate, sodium nitrite, sodium aluminate, and sodium hydroxide. The salt solution, supernate, contains cesium-137 and strontium-90. The radioactive cesium and strontium will be removed from the supernate by an In-Tank Precipation Process as part of a permanent radioactive waste disposal plan. In the Precipitation Process, sodium tetraphenylborate is used to precipitate cesium and sodium titanate is used to adsorb strontium. Potassium also precipitates, forming potassium tetraphenylborate, which is a major solid component of the slurry. The slurry is washed with water to decrease the amount of soluble solids in the solution. After the phenyl groups are removed by the Precipitate Hydrolysis Process, the radionuclides will be incorporated into borosilicate glass in the Defense Waste Processing Facility. Rheological properties of slurry are needed to design slurry pumps, transfer pumps, transfer lines, and vessel agitation. Studies were conducted to determine the transport characteristics of the tetraphenylborate precipitate slurry. This paper presents rheological information on a simulated nonradioactive potassium tetraphenylborate precipitate

183

Polymer electrolytes for a rechargeable li-Ion battery  

Energy Technology Data Exchange (ETDEWEB)

Lithium-ion polymer electrolyte battery technology is attractive for many consumer and military applications. A Li{sub x}C/Li{sub y}Mn{sub 2}O{sub 4} battery system incorporating a polymer electrolyte separator base on novel Li-imide salts is being developed under sponsorship of US Army Research Laboratory (Fort Monmouth NJ). This paper reports on work currently in progress on synthesis of Li-imide salts, polymer electrolyte films incorporating these salts, and development of electrodes and cells. A number of Li salts have been synthesized and characterized. These salts appear to have good voltaic stability. PVDF polymer gel electrolytes based on these salts have exhibited conductivities in the range 10{sup -4} to 10{sub -3} S/cm.

Argade, S.D.; Saraswat, A.K.; Rao, B.M.L. [Technochem Co., Greensboro, NC (United States); Lee, H.S.; Xiang, C.L.; McBreen, J. [Brookhaven National Lab., Upton, NY (United States)

1996-10-01

184

Electrolyte modified photoelectrochemical solar cells  

Energy Technology Data Exchange (ETDEWEB)

Rationale electrolyte modification of photoelectrochemical systems can be used to (1) enhance facile charge transfer, (2) suppress competing reactions and suppress both (3) electrode and (4) electrolyte decomposition products, as well as (5) substantially effect the open-circuit photovoltage. Studies on polysulfide, ferrocyanide, polyselenide and polyiodide electrolyte modification of photoelectrochemical solar cells are discussed. Electrolyte modification of semiconductor/electrolyte systems entails investigation of the primary photo-redox species, the nature of the counter ion, the distribution of species in solution, and related competing reactions. The examples presented emphasize the fundamental and practical importance of probing the active electrolytic constituents pertinent to overall photoelectrochemical energy conversion

Licht, Stuart [Clark University, Department of Chemistry, Worcester, MA (United States)

1995-08-01

185

Toughness of membranes applied in polymer electrolyte fuel cells  

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.

Kiefer, J.; Brack, H.P.; Scherer, G.G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

186

Design of Hybrid Solid Polymer Electrolytes: Structure and Properties  

Science.gov (United States)

This paper reports synthesis, structure, and properties of novel hybrid solid polymer electrolytes (SPE's) consisting of organically modified aluminosilica (OM-ALSi), formed within a poly(ethylene oxide)-in-salt (Li triflate) phase. To alter the structure and properties we fused functionalized silanes containing poly(ethylene oxide) (PEO) tails or CN groups.

Bronstein, Lyudmila M.; Karlinsey, Robert L.; Ritter, Kyle; Joo, Chan Gyu; Stein, Barry; Zwanziger, Josef W.

2003-01-01

187

Structural Rheology of the Smectic Phase  

Directory of Open Access Journals (Sweden)

Full Text Available In this review article, we discuss the rheological properties of the thermotropic smectic liquid crystal 8CB with focal conic domains (FCDs from the viewpoint of structural rheology. It is known that the unbinding of the dislocation loops in the smectic phase drives the smectic-nematic transition. Here we discuss how the unbinding of the dislocation loops affects the evolution of the FCD size, linear and nonlinear rheological behaviors of the smectic phase. By studying the FCD formation from the perpendicularly oriented smectic layers, we also argue that dislocations play a key role in the structural development in layered systems. Furthermore, similarities in the rheological behavior between the FCDs in the smectic phase and the onion structures in the lyotropic lamellar phase suggest that these systems share a common physical origin for the elasticity.

Shuji Fujii

2014-07-01

188

Becker and Lomnitz rheological models: a comparison  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The viscoelastic material functions for the Becker and the Lomnitz rheological models, sometimes employed to describe the transient flow of rocks, are studied and compared. Their creep functions, which are known in a closed form, share a similar time dependence and asymptotic behavior. This is also found for the relaxation functions, obtained by solving numerically a Volterra equation of the second kind. We show that the two rheologies constitute a clear example of broadly s...

Mainardi, Francesco; Spada, Giorgio

2012-01-01

189

Self-rheology of cell monolayers  

Science.gov (United States)

Collective migration of cell sheets is a central feature of fundamental biological processes including morphogenesis, tissue regeneration, and cancer invasion. The dynamics of such processes are heavily determined by the rheology of the sheet and of the constituent cells. Such material properties have been extensively measured using a broad variety of rheological techniques, but none of these techniques has probed the ultraslow time scales that are central to collective cell migration, and exceed thousands of seconds. Here we present a novel approach we call `Self rheology' that probes cell rheology using the pulses of strain rate that cells spontaneously generate. Using this approach, we show that stress and strain rate are in quadrature, thus indicating that the dominant stresses that govern collective cell migration are elastic. The monolayer's Young modulus is found to be an order of magnitude lower than the stiffness of single cells determined through active micro-rheology techniques at shorter time scales. This elastic behavior is followed by a fluidization regime at higher strains, which we interpret in terms of cell rearrangements. ``Self-rheology'' provides a new approach to study the dynamics of collective cellular processes at ultraslow time scales.

Vincent, Romaric; Serra-Picamal, Xavier; Conte, Vito; Anon, Ester; Trepat, Xavier

2012-02-01

190

Design and Synthesis of Cross-Linked Copolymer Membranes Based on Poly(benzoxazine) and Polybenzimidazole and Their Application to an Electrolyte Membrane for a High-Temperature PEM Fuel Cell  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Elevated-temperature (100~200 °C) polymer electrolyte membrane (PEM) fuel cells have many features, such as their high efficiency and simple system design, that make them ideal for residential micro-combined heat and power systems and as a power source for fuel cell electric vehicles. A proton-conducting solid-electrolyte membrane having high conductivity and durability at elevated temperatures is essential, and phosphoric-acid-containing polymeric material synthesized from cross-linked poly...

Hyuk Chang; Jong-Chan Lee; Kyoung Hwan Choi; Chanho Pak; Seong-Woo Choi; Jung Ock Park

2013-01-01

191

Electrolyte for electrodeposition of rhenium  

International Nuclear Information System (INIS)

An electrolyte is proposed for electrochemical deposition of rhenium, comprising ammonium perrhenate and hydrofluoric acid, characterized by the fact that to produce rhenium coatings of black colour the electrolyte incorporates sodium hydroxide and thiorea

192

Rheology of semisolid metal suspensions  

Science.gov (United States)

The importance of processing metals in their semisolid state is increasing quite rapidly due to the distinct advantages the process offers over similar methods of near-net-shape making. However, despite the attractive features of the process, its implementation to industrial applications is hampered by technical problems primarily due to the complex rheology of the material. In this work we have developed three mathematical models addressing the transient rheology of this complicated material. The models have been implemented into computational codes to predict the material behavior in problems such as the flow in a straight channel and in a sudden square expansion. As a first attempt in the modeling, and consistent with the experimental evidence, the behavior of a SSM is represented by a Herschel-Bulkley fluid. In this investigation, by using analytic solutions for antiplane shear flow in a corner between two rigid walls, we discuss the ability of regularized Herschel-Bulkley models in determining the topography of the yield surfaces. Results are shown for different flow parameters and compared to the exact solutions. The time evolution of the three-dimensional yielded/unyielded surfaces has been investigated in a sudden-square expansion with a downstream-to-upstream expansion ratio of 2:1. The results show that during the evolution of the flow, two core regions and dead zones at the corners are formed. The extent of the core regions decreases with the pressure gradient and the Reynolds number and increases with the power-law index. We propose a constitutive relation based on the same Herschel-Bulkley fluid model mentioned above, now however the rheological parameters are functions of the solid volume fraction and a structural parameter that evolves with the processing history. The framework of the proposed theory is validated using experimental data. The model is implemented into a 3-d computer code to predict the flow field, yield surfaces, and distribution of parameters in a channel flow. The results indicate that the break-down of links is rather small in the corners and in the core region of the channel. The models described above are quite effective in representing the bulk behavior of the flow of semisolid metals. However, more detailed information about the microstructure of the material is obtained by taking into account the two-phase nature of the slurry. In this investigation, we used a two-phase model to predict the isothermal flow behavior of semisolid metals in a sudden 3-D square expansion. The model considers that the liquid-phase behaves as a Newtonian fluid while the solid-phase behaves as a Herschel-Bulkley fluid. The model is implemented numerically using a classical Galerkin-Finite element formulation with a segregated solution procedure. The results show that segregation of phases exists resulting in particle crowding in the corners of the channel. (Abstract shortened by UMI.)

Burgos, Gilmer R.

1999-07-01

193

Comportamento reológico de suspensões aquosas de cromito de lantânio Rheological behaviour of lanthanum chromite aqueous suspension  

Directory of Open Access Journals (Sweden)

Full Text Available O cromito de lantânio (LaCrO3 é o material mais estudado para a produção de interconectores para células a combustível de ??xido sólido (SOFC. Devido a complexidade das microestruturas e geometrias das SOFCs, freqüentemente são necessárias, técnicas de processamento coloidal, os quais têm recebido maior atenção nos últimos anos por permitirem a obtenção de partes complexas com microestrutura controlada e reprodutíveis. Nos últimos anos, muito esforço tem sido direcionado ao processamento dos eletrólitos e eletrodos, mas aos componentes como o interconector, pouca atenção tem sido dada. Este artigo apresenta o estudo reológico e de conformação em moldes de gesso do cromito de lantânio para a produção de interconectores para SOFCs. A composição La0,80Sr0,20Cr0,92Co0,08O3, obtida por reação de combustão, foi utilizada. As suspensões aquosas foram preparadas com conteúdo de sólidos variando de 8 a 17,5% vol. utilizando-se, poliacrilato de amônia (PAA como polieletrólito/dispersante e hidróxido de tetrametilamônio (HTMA como provedor de alcalinidade. A influência da concentração dos aditivos e o tempo em moinho de bolas foram estudados. Os resultados indicam que o tempo 24 h de homogeneização em moinho de bolas, com 3% e 1%, em massa, de PAA e HTMA respectivamente, proporcionam as melhores condições para colagem em moldes de gesso, sendo possível obter peças após sinterização com densidades relativas elevadas.Lanthanum chromite (LaCrO3 is the most studied material for SOFC's interconnectors' production. The complexity of microstructures and geometries of SOFC devices often requires the use of colloidal processing techniques, which have received increased attention in the last years for obtaining complex parts with controlled microstructure and high reliability. Much effort has been devoted to the processing of electrodes and electrolytes but the other layers, such as that of interconnecting material, have received scarce attention. This paper deals with the rheology and casting behaviour of lanthanum chromite based materials to produce interconnectors for SOFCs. A powder with the composition La0.80Sr0.20Cr0.92Co0.08O3 was obtained by combustion synthesis. Aqueous suspensions were prepared to solids loading ranging from 8 to 17.5 vol.%, using ammonium polyacrylate (PAA as polyelectrolyte/dispersant and tetramethylammonium hydroxide (TMAH to assure basic pH. The influence of the additives concentrations and suspension ball milling time were studied. Suspensions prepared with 24 h ball milling, with 3 wt.% and 1 wt.%, of PAA and TMAH respectively, yielded the best conditions for successful slip casting, leading to relatively dense sintered materials.

L. F. G. Setz

2011-06-01

194

Comportamento reológico de suspensões aquosas de cromito de lantânio / Rheological behaviour of lanthanum chromite aqueous suspension  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O cromito de lantânio (LaCrO3) é o material mais estudado para a produção de interconectores para células a combustível de óxido sólido (SOFC). Devido a complexidade das microestruturas e geometrias das SOFCs, freqüentemente são necessárias, técnicas de processamento coloidal, os quais têm recebido [...] maior atenção nos últimos anos por permitirem a obtenção de partes complexas com microestrutura controlada e reprodutíveis. Nos últimos anos, muito esforço tem sido direcionado ao processamento dos eletrólitos e eletrodos, mas aos componentes como o interconector, pouca atenção tem sido dada. Este artigo apresenta o estudo reológico e de conformação em moldes de gesso do cromito de lantânio para a produção de interconectores para SOFCs. A composição La0,80Sr0,20Cr0,92Co0,08O3, obtida por reação de combustão, foi utilizada. As suspensões aquosas foram preparadas com conteúdo de sólidos variando de 8 a 17,5% vol. utilizando-se, poliacrilato de amônia (PAA) como polieletrólito/dispersante e hidróxido de tetrametilamônio (HTMA) como provedor de alcalinidade. A influência da concentração dos aditivos e o tempo em moinho de bolas foram estudados. Os resultados indicam que o tempo 24 h de homogeneização em moinho de bolas, com 3% e 1%, em massa, de PAA e HTMA respectivamente, proporcionam as melhores condições para colagem em moldes de gesso, sendo possível obter peças após sinterização com densidades relativas elevadas. Abstract in english Lanthanum chromite (LaCrO3) is the most studied material for SOFC's interconnectors' production. The complexity of microstructures and geometries of SOFC devices often requires the use of colloidal processing techniques, which have received increased attention in the last years for obtaining complex [...] parts with controlled microstructure and high reliability. Much effort has been devoted to the processing of electrodes and electrolytes but the other layers, such as that of interconnecting material, have received scarce attention. This paper deals with the rheology and casting behaviour of lanthanum chromite based materials to produce interconnectors for SOFCs. A powder with the composition La0.80Sr0.20Cr0.92Co0.08O3 was obtained by combustion synthesis. Aqueous suspensions were prepared to solids loading ranging from 8 to 17.5 vol.%, using ammonium polyacrylate (PAA) as polyelectrolyte/dispersant and tetramethylammonium hydroxide (TMAH) to assure basic pH. The influence of the additives concentrations and suspension ball milling time were studied. Suspensions prepared with 24 h ball milling, with 3 wt.% and 1 wt.%, of PAA and TMAH respectively, yielded the best conditions for successful slip casting, leading to relatively dense sintered materials.

L. F. G., Setz; I., Santacruz; M. T., Colomer; R., Moreno; S. R. H., Mello-Castanho.

2011-06-01

195

Comportamento reológico de suspensões aquosas de cromito de lantânio / Rheological behaviour of lanthanum chromite aqueous suspension  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O cromito de lantânio (LaCrO3) é o material mais estudado para a produção de interconectores para células a combustível de óxido sólido (SOFC). Devido a complexidade das microestruturas e geometrias das SOFCs, freqüentemente são necessárias, técnicas de processamento coloidal, os quais têm recebido [...] maior atenção nos últimos anos por permitirem a obtenção de partes complexas com microestrutura controlada e reprodutíveis. Nos últimos anos, muito esforço tem sido direcionado ao processamento dos eletrólitos e eletrodos, mas aos componentes como o interconector, pouca atenção tem sido dada. Este artigo apresenta o estudo reológico e de conformação em moldes de gesso do cromito de lantânio para a produção de interconectores para SOFCs. A composição La0,80Sr0,20Cr0,92Co0,08O3, obtida por reação de combustão, foi utilizada. As suspensões aquosas foram preparadas com conteúdo de sólidos variando de 8 a 17,5% vol. utilizando-se, poliacrilato de amônia (PAA) como polieletrólito/dispersante e hidróxido de tetrametilamônio (HTMA) como provedor de alcalinidade. A influência da concentração dos aditivos e o tempo em moinho de bolas foram estudados. Os resultados indicam que o tempo 24 h de homogeneização em moinho de bolas, com 3% e 1%, em massa, de PAA e HTMA respectivamente, proporcionam as melhores condições para colagem em moldes de gesso, sendo possível obter peças após sinterização com densidades relativas elevadas. Abstract in english Lanthanum chromite (LaCrO3) is the most studied material for SOFC's interconnectors' production. The complexity of microstructures and geometries of SOFC devices often requires the use of colloidal processing techniques, which have received increased attention in the last years for obtaining complex [...] parts with controlled microstructure and high reliability. Much effort has been devoted to the processing of electrodes and electrolytes but the other layers, such as that of interconnecting material, have received scarce attention. This paper deals with the rheology and casting behaviour of lanthanum chromite based materials to produce interconnectors for SOFCs. A powder with the composition La0.80Sr0.20Cr0.92Co0.08O3 was obtained by combustion synthesis. Aqueous suspensions were prepared to solids loading ranging from 8 to 17.5 vol.%, using ammonium polyacrylate (PAA) as polyelectrolyte/dispersant and tetramethylammonium hydroxide (TMAH) to assure basic pH. The influence of the additives concentrations and suspension ball milling time were studied. Suspensions prepared with 24 h ball milling, with 3 wt.% and 1 wt.%, of PAA and TMAH respectively, yielded the best conditions for successful slip casting, leading to relatively dense sintered materials.

L. F. G., Setz; I., Santacruz; M. T., Colomer; R., Moreno; S. R. H., Mello-Castanho.

196

Batteries using molten salt electrolyte  

Science.gov (United States)

An electrolyte system suitable for a molten salt electrolyte battery is described where the electrolyte system is a molten nitrate compound, an organic compound containing dissolved lithium salts, or a 1-ethyl-3-methlyimidazolium salt with a melting temperature between approximately room temperature and approximately 250.degree. C. With a compatible anode and cathode, the electrolyte system is utilized in a battery as a power source suitable for oil/gas borehole applications and in heat sensors.

Guidotti, Ronald A. (Albuquerque, NM)

2003-04-08

197

Electrolytic production of praseodymium  

International Nuclear Information System (INIS)

A method is described for preparing praseodymium metal by electrolyzing praseodymium oxide in a molten electrolyte comprising lithium fluoride and praseodymium fluoride, wherein an initial weight ratio of lithium fluoride to praseodymium fluoride is about 0.1 to about 0.4 and collecting the praseodymium metal at temperatures at or above the melting point of the metal

198

Electrolytes for tungsten refining  

International Nuclear Information System (INIS)

Alkali metal chloride-fluoride and phosphate-fluoride salts with additions of sodium tungstate and tungsten anhydride are investigated aimed to be used as an electrolyte for tungsten refining. The realization of electrolysis in given molten salts is established to be radically possible. Coarsely crystalline tungsten powder of higher purity in a number of impurities is produced

199

Rheological behaviour of irradiated wound dressing poly(vinyl pyrrolidone) hydrogels  

International Nuclear Information System (INIS)

The use of hydrogels as biomaterials has increased lately. Poly(vinyl pyrrolidone) (PVP) is an example of polymer hydrogels applied for the synthesis of hydrogel to be used in different biomedical applications. This paper describes a study on rheological properties of PVP hydrogels obtained by gamma radiation techniques. PVP hydrogels were obtained by gamma radiation of PVP water solutions with different radiation doses. It was studied the influence of additives such as poly(ethylene glycol) (PEG), poly(ethylene oxide) (PEO) and glycerol on the rheological behaviour of the gel. The rheological behaviour of hydrogel samples was characterized by measuring the shear storage modulus (G') under dynamic shear loading. Besides this, sterility and cytotoxicity tests were performed. The study on rheological behaviour of hydrogels showed that G' of PVP gels change according to the additive used. Glycerol increases the fluidity of the gel. The influence of PEG depends on the amount and on its molecular mass. The increase on PEG amount and molecular mass cause a decrease of G' and an increase in the crosslinking density of PVP hydrogel network. The use of high molecular weight PEO allows the increase of the elasticity of the PVP gels

200

Nicotine alters mucin rheological properties.  

Science.gov (United States)

Tobacco smoke exposure, the major cause of chronic obstructive pulmonary disease (COPD), instigates a dysfunctional clearance of thick obstructive mucus. However, the mechanism underlying the formation of abnormally viscous mucus remains elusive. We investigated whether nicotine can directly alter the rheological properties of mucin by examining its physicochemical interactions with human airway mucin gels secreted from A549 lung epithelial cells. Swelling kinetics and multiple particle tracking were utilized to assess mucin gel viscosity change when exposed to nicotine. Herein we show that nicotine (?50 nM) significantly hindered postexocytotic swelling and hydration of released mucins, leading to higher viscosity, possibly by electrostatic and hydrophobic interactions. Moreover, the close association of nicotine and mucins allows airway mucus to function as a reservoir for prolonged nicotine release, leading to correlated pathogenic effects. Our results provide a novel explanation for the maltransport of poorly hydrated mucus in smokers. More importantly, this study further indicates that even low-concentration nicotine can profoundly increase mucus viscosity and thus highlights the health risks of secondhand smoke exposure. PMID:24838753

Chen, Eric Y; Sun, Albert; Chen, Chi-Shuo; Mintz, Alexander J; Chin, Wei-Chun

2014-07-15

 
 
 
 
201

Rheology of surface granular flows  

CERN Document Server

The rheology of surface granular flows is investigated by means of measurements of velocity and number density profiles in a quasi-two-dimensional rotating cylinder, half-filled with mono-disperse steel balls. The measurements are made at the center of the cylinder, where the flow is fully-developed, using streakline photography and image analysis . The stress profile is computed from the number density profile using a force balance taking into account wall friction. The profiles for the mean velocity superimpose when distance is scaled by the particle diameter and the velocity by a characteristic shear rate and the particle diameter. The mean velocity is found to decay exponentially with depth in the bed with a decay length of $\\lambda=1.1d$. The r.m.s. velocity is nearly constant near the free surface and below a transition point it decays linearly with depth. The shear rate, obtained by numerical differentiation of the velocity profile, shows a maximum which occurs at the same depth as the transition in th...

Orpe, A V; Orpe, Ashish V.

2005-01-01

202

Lubricant Rheology in Concentrated Contacts  

Science.gov (United States)

Lubricant behavior in highly stressed situtations shows that a Newtonian model for lubricant rheology is insufficient for explanation of traction behavior. The oil film build up is predicted by using a Newtonian lubricant model except at high slide to roll ratios and at very high loads, where the nonNewtonian behavior starts to be important already outside the Hertzian contact area. Static and dynamic experiments are reported. In static experiments the pressure is applied to the lubricant more than a million times longer than in an EHD contact. Depending on the pressure-temperature history of the experiment the lubricant will become a crystallized or amorphous solid at high pressures. In dynamic experiments, the oil is in an amorphous solid state. Depending on the viscosity, time scale, elasticity of the oil and the bearing surfaces, the oil film pressure, shear strain rate and the type of lubricant, different properties of the oil are important for prediction of shear stresses in the oil. The different proposed models for the lubricant, which describe it to a Newtonian liquid, an elastic liquid, a plastic liquid and an elastic-plastic solid.

Jacobson, B. O.

1984-01-01

203

Rheology of tetraphenylborate precipitate slurry  

International Nuclear Information System (INIS)

The rheological properties of tetraphenylborate precipitate slurry were determined. This nonradioactive slurry simulates the radioactive tetraphenylborate precipitate generated at the Savannah River Plant by the In-Tank Precipitation Process. The data obtained in this study was applied in the design of slurry pumps, transfer pumps, transfer lines, and vessel agitation for the Defense Waste Processing Facility and other High Level Waste treatment projects. The precipitate slurry behaves as a Bingham plastic. The yield stress is directly proportional to the concentration of insoluble solids over the range of concentrations studied. The consistency is also a linear function of insoluble solids over the same concentration range. Neither the yield stress nor the consistency was observed to be affected by the presence of the soluble solids. Temperature effects on flow properties of the slurry were also examined: the yield stress is inversely proportional to temperature, but the consistency of the slurry is independent of temperature. No significant time-dependent effects were found. 4 refs., 4 figs., 3 tabs

204

Initial rheological description of high performance concretes  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Concrete is defined as a composite material and, in rheological terms, it can be understood as a concentrated suspension of solid particles (aggregates) in a viscous liquid (cement paste). On a macroscopic scale, concrete flows as a liquid. It is known that the rheological behavior of the concrete i [...] s close to that of a Bingham fluid and two rheological parameters regarding its description are needed: yield stress and plastic viscosity. The aim of this paper is to present the initial rheological description of high performance concretes using the modified slump test. According to the results, an increase of yield stress was observed over time, while a slight variation in plastic viscosity was noticed. The incorporation of silica fume showed changes in the rheological properties of fresh concrete. The behavior of these materials also varied with the mixing procedure employed in their production. The addition of superplasticizer meant that there was a large reduction in the mixture's yield stress, while plastic viscosity remained practically constant.

Alessandra Lorenzetti de, Castro; Jefferson Benedicto Libardi, Liborio.

2006-12-01

205

Unified Solid-Viscous Mantle Rheology  

Science.gov (United States)

Despite their general similarities, the existing models for seismic, tidal, and geodynamic anelasticity of the Earth are difficult to compare quantitatively. The principal problem is that the viscoelastic quality factor Q, which is typically used for describing the near-elastic energy dissipation, is often incompatible with mechanics. To resolve this inconsistency, we present a new formulation of anelasticity based entirely on analytical mechanics. The Jeffreys-Ricker model of "solid friction" is recast in Lagrangian form in terms of viscosities, and extended to non-Newtonian rheologies. A unified model of the Earth's anelasticity is thus created by using a dissipation function, D, which is dependent on both strains and strain rates. This function gives a common rheological law describing the behavior of Earth's materials under seismic, tidal, quasi-static laboratory (creep), and geodynamic conditions. Function D is both strain and strain-rate dependent, and its dependence on strain rate is close to the power-law rheological relation commonly used in geodynamics. The dependence on strain varies from power-law in the elastic limit to constant in the plastic-flow limit. For the mantle, the characteristic value of the proposed "rheological viscosity" is estimated as 2.109 Pa.s, and the two power-law exponents are ?0 = 0.47 (for weak strain) and ?1 = 0.6 (for strain rate). With such a common rheological law and rigorous mechanical formulation, a unified picture of physical processes within the Earth becomes possible at all scales.

Morozov, I. B.

2011-12-01

206

The rheology of chain molecules under shear  

Science.gov (United States)

The rheology of chain molecules is a subject that comprises a wide variety of complex physical phenomena, challenging scientific questions, and fundamentally important practical applications. In this work, nonequilibrium molecular dynamics (NEMD) is employed to study linear and branched alkane chains in the melt state under transient and steady-state shearing conditions. This study focuses on three isomers of C30H62 (n- triacontane, squalane, and 9-n- octyldocosane) as well as a linear short-chain polyethylene (C100H202). A transferable united atom potential is used to model these alkane chains, and the simulations of planar Couette flow are performed using the SLLOD algorithm and a multi- timestep, simulation technique. The strain rates studied in this work (108-10 12 s-1) are extremely difficult to study experimentally yet typical of the severe conditions commonly found in engines and other machinery. NEMD and the united atom model underpredict the kinematic viscosities of n-triacontane and 9- n-octyldocosane but accurately predict the values for squalane (within 15%) at temperatures of 311 and 372 K. The predicted kinematic viscosity index values for both 9- n-octyldocosane and squalane are in quantitative agreement with experiment and represent the first such predictions by molecular simulation. Thus, this same general potential model and computational approach can be used to predict this important lubricant property for potential lubricants prior to their synthesis, offering the possibility of simulation-guided lubricant design. Simulations of C100H202 under steady-state shearing conditions reveal a pronounced minimum in the hydrostatic pressure at an intermediate strain rate that is associated with a minimum in the intermolecular potential energy as well as transitions in the strain-rate-dependent behavior of several other viscous and structural properties of the system. Upon onset of shear, the stress overshoot curves calculated for C100 are in good quantitative agreement with Doi-Edwards theory if the terminal relaxation time is assumed to have the same strain-rate dependence as the calculated self-diffusion coefficient in the flow direction. This shear-enhanced diffusion offers a possible mechanism for strain-rate-dependent relaxation times in the fast flows of polymers.

Moore, Jonathan David

207

Electrolytic 99TcO4- reduction at inert electrodes  

International Nuclear Information System (INIS)

Electrolytic pertechnetate reduction at inert electrodes was studied as an alternative procedure for synthesizing Tc complexes. Pertechnetate reduction was carried out in aqueous media using different aminated ligands (en, dien, trien and 1,3-dap) forming [TcO2(amine)2]+ type complexes. Simultaneously with synthesis of the desired Tc complex, TcO2 was electrodeposited onto the cathode. Conversion of TcO4- to Tc complex and TcO2 was studied as a function of several variables (kind and concentration of supporting electrolyte, ligand concentration, pH, current and electrolysis time). (author) 9 refs.; 6 figs.; 1 tab

208

Rheological behavior study of a clay-polymer mixture: effects of the polymer addition; Etude du comportement rheologique de melanges argiles - polymeres. Effets de l'ajout de polymeres  

Energy Technology Data Exchange (ETDEWEB)

The aim of the present work is to establish a bibliographical synthesis on the microstructure, the colloidal and rheological characterization of bentonite suspensions with and without polymer/surfactant addition; to lead to a rheological characterization of clay-additive mixtures and to understand the interaction between the clay particles and polymer/surfactants. Different experimental measurements: rheology, particle sizing, and x-ray diffraction were used to study the rheological character of the water-bentonite-anionic additive mixtures (CMC, SDS, xanthane) as well as the nature of the particle-particle interactions and particle-additive. The modeling part led to the adoption of Tiu and Boger's model to predict the thixotropy of the bentonite suspensions without additive. Thus, a new model is proposed with physical parameters for a better correlation of the rheological behavior of the various studied mixtures. (author)

Benchabane, A

2006-11-15

209

Rheological properties of alumina injection feedstocks  

Directory of Open Access Journals (Sweden)

Full Text Available The rheological behavior of alumina molding feedstocks containing polyethylene glycol (PEG, polyvinylbutyral (PVB and stearic acid (SA and having different powder loads were analyzed using a capillary rheometer. Some of the feedstocks showed a pseudoplastic behavior of n < 0, which can lead to the appearance of weld lines on molded parts. Their viscosity also displayed a strong dependence on the shear rate. The slip phenomenon, which can cause an unsteady front flow, was also observed. The results indicate that the feedstock containing a lower powder load displayed the best rheological behavior. The 55 vol. % powder loaded feedstock presented the best rheological behavior, thus appearing to be more suitable than the formulation containing a vol. 59% powder load, which attained viscosities exceeding 10³ Pa.s at low shear rates, indicating its unsuitability for injection molding.

Vivian Alexandra Krauss

2005-06-01

210

Rheological properties of alumina injection feedstocks  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The rheological behavior of alumina molding feedstocks containing polyethylene glycol (PEG), polyvinylbutyral (PVB) and stearic acid (SA) and having different powder loads were analyzed using a capillary rheometer. Some of the feedstocks showed a pseudoplastic behavior of n [...] e appearance of weld lines on molded parts. Their viscosity also displayed a strong dependence on the shear rate. The slip phenomenon, which can cause an unsteady front flow, was also observed. The results indicate that the feedstock containing a lower powder load displayed the best rheological behavior. The 55 vol. % powder loaded feedstock presented the best rheological behavior, thus appearing to be more suitable than the formulation containing a vol. 59% powder load, which attained viscosities exceeding 10³ Pa.s at low shear rates, indicating its unsuitability for injection molding.

Vivian Alexandra, Krauss; Eduardo Nunes, Pires; Aloísio Nelmo, Klein; Márcio Celso, Fredel.

2005-06-01

211

Rheological properties of alumina injection feedstocks  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The rheological behavior of alumina molding feedstocks containing polyethylene glycol (PEG), polyvinylbutyral (PVB) and stearic acid (SA) and having different powder loads were analyzed using a capillary rheometer. Some of the feedstocks showed a pseudoplastic behavior of n [...] e appearance of weld lines on molded parts. Their viscosity also displayed a strong dependence on the shear rate. The slip phenomenon, which can cause an unsteady front flow, was also observed. The results indicate that the feedstock containing a lower powder load displayed the best rheological behavior. The 55 vol. % powder loaded feedstock presented the best rheological behavior, thus appearing to be more suitable than the formulation containing a vol. 59% powder load, which attained viscosities exceeding 10³ Pa.s at low shear rates, indicating its unsuitability for injection molding.

Vivian Alexandra, Krauss; Eduardo Nunes, Pires; Aloísio Nelmo, Klein; Márcio Celso, Fredel.

212

The debris-flow rheology myth  

Science.gov (United States)

Models that employ a fixed rheology cannot yield accurate interpretations or predictions of debris-flow motion, because the evolving behavior of debris flows is too complex to be represented by any rheological equation that uniquely relates stress and strain rate. Field observations and experimental data indicate that debris behavior can vary from nearly rigid to highly fluid as a consequence of temporal and spatial variations in pore-fluid pressure and mixture agitation. Moreover, behavior can vary if debris composition changes as a result of grain-size segregation and gain or loss of solid and fluid constituents in transit. An alternative to fixed-rheology models is provided by a Coulomb mixture theory model, which can represent variable interactions of solid and fluid constituents in heterogeneous debris-flow surges with high-friction, coarse-grained heads and low-friction, liquefied tails. ?? 2003 Millpress.

Iverson, R.M.

2003-01-01

213

Thin film composite electrolyte  

Science.gov (United States)

The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

Schucker, Robert C. (The Woodlands, TX)

2007-08-14

214

Electrolyte disorders and arrhythmogenesis.  

Science.gov (United States)

Electrolyte disorders can alter cardiac ionic currents kinetics and depending on the changes can promote proarrhythmic or antiarrhythmic effects. The present report reviews the mechanisms, electrophysiolgical (EP), electrocardiographic (ECG), and clinical consequences of electrolyte disorders. Potassium (K?) is the most abundent intracellular cation and hypokalemia is the most commont electrolyte abnormality encountered in clinical practice. The most significant ECG manifestation of hypokalemia is a prominent U wave. Several cardiac and non cardiac drugs are known to suppress the HERG K? channel and hence the I(K), and especially in the presence of hypokalemia, can result in prolonged action potential duration and QT interval, QTU alternans, early afterdepolarizations, and torsade de pointes ventricular tachyarrythmia (TdP VT). Hyperkalemia affects up to 8% of hospitalized patients mainly in the setting of compromised renal function. The ECG manifestation of hyperkalemia depends on serum K? level. At 5.5-7.0 mmol/L K?, tall peaked, narrow-based T waves are seen. At > 10.0 mmol/L K?, sinus arrest, marked intraventricular conduction delay, ventricular techycardia, and ventricular fibrillation can develop. Isolated abnormalities of extracellular calcium (Ca??) produce clinically significant EP effects only when they are extreme in either direction. Hypocalcemia, frequently seen in the setting of chronic renal insufficiency, results in prolonged ST segment and QT interval while hypercalcemia, usually seen with hyperparathyroidism, results in shortening of both intervals. Although magnesium is the second most abudent intracellular cation, the significance of magnesium disorders are controversial partly because of the frequent association of other electrolyte abnormalities. However, IV magnesium by blocking the L-type Ca(??) current can successfully terminate TdP VT without affecting the prolonged QT interval. Finally, despite the frequency of sodium abnormalities, particularly hyponatremia, its EP effects are rarely clinically significant. PMID:21660912

El-Sherif, Nabil; Turitto, Gioia

2011-01-01

215

Rheological study of chitosan in solution  

International Nuclear Information System (INIS)

Chitosan is an abundant biopolymer with remarkable physicochemical and biological properties, usually employed in a wide range of applications. It acts as a cationic polyelectrolyte in aqueous acid solutions, leading to unique characteristics. In this work, chitosan was characterized by 1H NMR and its rheological behavior were studied as function of chitosan sample, shear rate, polymer concentration, ionic strength, time and temperature. In order to calculate rheological parameters and to understand the macromolecular dynamic in solution, the Otswald-de Waele model was fitted. (author)

216

Rheology of zirconia-alumina gelcasting slurries  

International Nuclear Information System (INIS)

This paper reports that the rheology of zirconia-alumina composite slurries for gelcasting was studied in order to maximize the solids loading. The viscosity and yield stress were controlled by adjusting the pH. This approach allows the solids loading to be maximized for the gelcasting of near-net-shape composites. A strong correspondence exists among the rheological behavior, the surface charge on the particles, colloidal stability, and the maximum solids loading. The best pH conditions for gelcasting composites depends on the specific binary compositions

217

Becker and Lomnitz rheological models: A comparison  

Science.gov (United States)

The viscoelastic material functions for the Becker and the Lomnitz rheological models, sometimes employed to describe the transient flow of rocks, are studied and compared. Their creep functions, which are known in a closed form, share a similar time dependence and asymptotic behavior. This is also found for the relaxation functions, obtained by solving numerically a Volterra equation of the second kind. We show that the two rheologies constitute a clear example of broadly similar creep and relaxation patterns associated with neatly distinct retardation spectra, for which analytical expressions are available.

Mainardi, Francesco; Spada, Giorgio

2012-07-01

218

Rheology of draining steady-state foams  

Science.gov (United States)

Aqueous foams continuously age due to fluid drainage and bubble coarsening, which makes it difficult to perform steady-state rheological measurements. Consequently we have developed the foam drainage rheology technique, where perfusion counteracts fluid drainage and bubble replenishment counteracts bubble coarsening during measurement of the shear stresses by a rheometer. We evaluate published power-law and Herschel-Bulkley models and find that parameters derived from emulsion experiments cannot describe our results. We propose a hybrid model, which combines our earlier film-shearing model, where the film thickness depends on liquid volume fraction, with a Herschel-Bulkley shear-rate dependence.

Soller, Raenell; Koehler, Stephan A.

2009-08-01

219

Rheology of draining steady-state foams.  

Science.gov (United States)

Aqueous foams continuously age due to fluid drainage and bubble coarsening, which makes it difficult to perform steady-state rheological measurements. Consequently we have developed the foam drainage rheology technique, where perfusion counteracts fluid drainage and bubble replenishment counteracts bubble coarsening during measurement of the shear stresses by a rheometer. We evaluate published power-law and Herschel-Bulkley models and find that parameters derived from emulsion experiments cannot describe our results. We propose a hybrid model, which combines our earlier film-shearing model, where the film thickness depends on liquid volume fraction, with a Herschel-Bulkley shear-rate dependence. PMID:19792130

Soller, Raenell; Koehler, Stephan A

2009-08-01

220

Rheology of the lithosphere: selected topics.  

Science.gov (United States)

Reviews recent results concerning the rheology of the lithosphere with special attention to the following topics: 1) the flexure of the oceanic lithosphere, 2) deformation of the continental lithosphere resulting from vertical surface loads and forces applied at plate margins, 3) the rheological stratification of the continents, 4) strain localization and shear zone development, and 5) strain-induced crystallographic preferred orientations and anisotropies in body-wave velocities. We conclude with a section citing the 1983-1986 rock mechanics literature by category.-Authors

Kirby, S.H.; Kronenberg, A.K.

1987-01-01

 
 
 
 
221

Osmotic coefficients of electrolyte solutions.  

Science.gov (United States)

In this paper, the osmotic coefficient, phi, of electrolyte solutions is considered. According to the Gibbs-Duhem equation, the calculation of phi follows from that of the mean activity coefficient, gamma, based on a pseudolattice approach recently proposed. For any given electrolyte, the whole range of concentrations providing gammaparameters where the (upper) concentration, clim, exists at which the electrolyte solution exhibits gamma=1. In the remaining cases, a unique parameter is required, that is, the value of clim that should ideally give gamma=1 for the electrolyte. Known values of clim from 1 up to 9 M (about) are available for several aqueous electrolytes at 25 degrees C. All formulas in this paper are applied for 1:1, 2:2, 1:2, and 2:1 aqueous electrolytes at 25 degrees C. PMID:18179191

Moggia, Elsa

2008-01-31

222

Lithium sulfide compositions for battery electrolyte and battery electrode coatings  

Science.gov (United States)

Methods of forming lithium-containing electrolytes are provided using wet chemical synthesis. In some examples, the lithium containing electroytes are composed of .beta.-Li.sub.3PS.sub.4 or Li.sub.4P.sub.2S.sub.7. The solid electrolyte may be a core shell material. In one embodiment, the core shell material includes a core of lithium sulfide (Li.sub.2S), a first shell of .beta.-Li.sub.3PS.sub.4 or Li.sub.4P.sub.2S.sub.7, and a second shell including one or .beta.-Li.sub.3PS.sub.4 or Li.sub.4P.sub.2S.sub.7 and carbon. The lithium containing electrolytes may be incorporated into wet cell batteries or solid state batteries.

Liang, Chengdu; Liu, Zengcai; Fu, Wunjun; Lin, Zhan; Dudney, Nancy J; Howe, Jane Y; Rondinone, Adam J

2013-12-03

223

Ceramic electrolyte coating and methods  

Science.gov (United States)

Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

Seabaugh, Matthew M. (Columbus, OH); Swartz, Scott L. (Columbus, OH); Dawson, William J. (Dublin, OH); McCormick, Buddy E. (Dublin, OH)

2007-08-28

224

NEW RHEOLOGICAL MODELS FOR MINERAL OIL  

Directory of Open Access Journals (Sweden)

Full Text Available This article proposes new rheological models for mineral oil. The purpose of this study was to find an exponential and linear dependence between temperature and dynamic viscosity of mineral oil, using the equations. Equation constants a, b c and ?o were determined by fitting exponential.

IOANA STANCIU

2013-03-01

225

RHEOLOGY OF CHICKPEA PROTEIN CONCENTRATE DISPERSIONS  

Directory of Open Access Journals (Sweden)

Full Text Available Chickpea proteins are used as ingredients in comminuted sausage products and many oriental textured foods. Rheological behaviour of chickpea protein concentrate was studied using a controlled stress rheometer. The protein dispersion prepared with phosphate buffer at pH 7.0 presented non-Newtonian shear thinning behaviour and rheological data well fitted to the Sisko, Carreau and Cross models. The viscoelastic properties of the chickpea protein suspensions were estimated by measuring the storage and loss moduli in oscillatory frequency conditions (0.1-10 Hz at 20°C. Moreover, thermally induced gelation of the chickpea proteins (16, 24 and 36% was studied at pH 7.0 and 4.5 in the temperature range 50 to 100oC and salt concentration ranging from 0 to 1 M. Gelling behaviour was quantified by means of dynamic rheological measurements. Gels formation was preceded by the decrease of storage modulus and loss moduli, coupled with the increase of the phase angle (delta. The beginning of thermal gelation was influenced by protein concentration, pH and salt level. In all studied cases, storage modulus increased rapidly in the temperature range 70-90°C. All rheological parameters measured at 90°C were significantly higher at pH 4.5 compared to pH 7.0.

Aurelia Ionescu

2011-12-01

226

Rheological properties of defense waste slurries  

Energy Technology Data Exchange (ETDEWEB)

The major objective of this two-year project has been to obtain refined and reliable experimental data about the rheological properties of melter feeds. The research has involved both experimental studies and model development. Two experimental facilities have been set up to measure viscosity and pressure drop. Mathematical models have been developed as a result of experimental observation and fundamental rheological theory. The model has the capability to predict the viscosity of melter slurries in a range of experimental conditions. The final results of the investigation could be used to enhance the current design base for slurry transportation systems and improve the performance of the slurry mixing process. If successful, the cost of this waste treatment will be reduced, and disposal safety will be increased. The specific objectives for this project included: (1) the design, implementation, and validation of the experimental facility in both batch and continuous operating modes; (2) the identification and preparation of melter feed samples of both the SRS and Hanford waste slurries at multiple solids concentration levels; (3) the measurement and analysis of the melter feeds to determine the effects of the solids concentration, pH value, and other factors on the rheological properties of the slurries; (4) the correlation of the rheological properties as a function of the measured physical and chemical parameters; and (5) transmission of the experimental data and resulting correlation to the DOE site user to guide melter feed preparation and transport equipment design.

Ebadian, M.A.

1998-01-01

227

RHEOLOGY OF CONCENTRATED SOLUTIONS OF HYPERBRANCHED POLYESTERS  

Science.gov (United States)

The solution rheology of different generations of hyperbranched polyesters in N-methyl-2- pyrrolidinone (NMP) solvent was examined in this study. The solutions exhibited Newtonian behavior over a wide range of polyester concentrations. Also, the relative viscosities of poly(amido...

228

Measurements and models of cytoskeletal rheology  

Science.gov (United States)

Much attention has recently focused on understanding the rheology of living cells and reconstituted actin gels using a variety of experimental methods (e.g., single- and multi-particle tracking, magnetic twisting cytometry, AFM indentation) and several different models or descriptors (e.g., biopolymer models, tensegrity, cellular solids, power-law rheology), but the debate continues regarding the fundamental basis for the experimental observations. Our recent studies examine the time-dependent behavior of neutrophils as they deform to enter a narrow channel with capillary-scale dimensions. A sudden drop in the shear modulus is observed, followed by recovery to pre-deformation values in agent. To better understand these processes and the nature of cytoskeletal rheology in general, we have developed a Brownian dynamics model for cytoskeletal self-assembly and subsequent rheological measurement by single particle tracking. Cross-linking proteins are included possessing a range of properties that lead to a variety of cytoskeletal structures from a fine, homogeneous mesh to a structure containing large stress fibers of varying thickness. These results are described in a multi-dimensional phase space that takes into account the geometry, dimensions and stiffness of the cross-linkers.

Kamm, Roger

2006-11-01

229

Rheological properties of defense waste slurries  

International Nuclear Information System (INIS)

The major objective of this two-year project has been to obtain refined and reliable experimental data about the rheological properties of melter feeds. The research has involved both experimental studies and model development. Two experimental facilities have been set up to measure viscosity and pressure drop. Mathematical models have been developed as a result of experimental observation and fundamental rheological theory. The model has the capability to predict the viscosity of melter slurries in a range of experimental conditions. The final results of the investigation could be used to enhance the current design base for slurry transportation systems and improve the performance of the slurry mixing process. If successful, the cost of this waste treatment will be reduced, and disposal safety will be increased. The specific objectives for this project included: (1) the design, implementation, and validation of the experimental facility in both batch and continuous operating modes; (2) the identification and preparation of melter feed samples of both the SRS and Hanford waste slurries at multiple solids concentration levels; (3) the measurement and analysis of the melter feeds to determine the effects of the solids concentration, pH value, and other factors on the rheological properties of the slurries; (4) the correlation of the rheological properties as a function of the measured physical and chemical parameters; and (5) transmission of the experimental data and resulting correlation to the DOE site user to guide melter feed preparation and transport equipment design

230

Aggregate of nanoparticles: rheological and mechanical properties  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract The understanding of the rheological and mechanical properties of nanoparticle aggregates is important for the application of nanofillers in nanocompoistes. In this work, we report a rheological study on the rheological and mechanical properties of nano-silica agglomerates in the form of gel network mainly constructed by hydrogen bonds. The elastic model for rubber is modified to analyze the elastic behavior of the agglomerates. By this modified elastic model, the size of the network mesh can be estimated by the elastic modulus of the network which can be easily obtained by rheology. The stress to destroy the aggregates, i.e., the yield stress (?y , and the elastic modulus (G' of the network are found to be depended on the concentration of nano-silica (?, wt.% with the power of 4.02 and 3.83, respectively. Via this concentration dependent behavior, we can extrapolate two important mechanical parameters for the agglomerates in a dense packing state (? = 1: the shear modulus and the yield stress. Under large deformation (continuous shear flow, the network structure of the aggregates will experience destruction and reconstruction, which gives rise to fluctuations in the viscosity and a shear-thinning behavior.

Wang Yu

2011-01-01

231

Rheological Modifier Testing with DWPF Process Slurries  

International Nuclear Information System (INIS)

Rheological modification agents were tested on simulated SRAT and SME products to determine if a suitable agent could be found for the DWPF process slurries. The agents tested were dispersants that lower the rheological properties of slurries by preventing agglomerization. Dolapix CE64, an ethylene glycol, and Disperse-Ayd W28, a polyacrylate, were the most effective dispersants tested. Further evaluation and testing should be performed on Dolapix CE64 and Disperse-Ayd W28 to determine if implementation is possible in DWPF. The initial phase of future work will include optimization of the rheology modifier by the Illinois Institute of Technology (IIT) and development of a maximum concentration limit for the rheology modifiers. IIT has been commissioned to evaluate the properties of these chemicals to determine if the chemical makeup can be optimized to enhance the properties of these modifiers. An initial concentration limit based upon the DWPF flammability limit and other constraints should be calculated to determine the potential downstream impacts

232

High voltage electrolytic cell  

International Nuclear Information System (INIS)

A novel electrode, an apparatus and a method are set out for electrolyzing a chloride ion containing aqueous solution to produce chlorine and ozone. Through utilization of a solid state rectifier network, and without the use of a transformer, full line voltage, after rectification, is applied between the anode and cathode of an electrolytic cell utilizing an anode which is a laminated body of a platinum group metal foil bonded to a tantalum or niobium layer which in turn is bonded to a titanium substrate. Chlorine and ozone production is quite rapid

233

Surface shear rheology of saponin adsorption layers.  

Science.gov (United States)

Saponins are a wide class of natural surfactants, with molecules containing a rigid hydrophobic group (triterpenoid or steroid), connected via glycoside bonds to hydrophilic oligosaccharide chains. These surfactants are very good foam stabiliziers and emulsifiers, and show a range of nontrivial biological activities. The molecular mechanisms behind these unusual properties are unknown, and, therefore, the saponins have attracted significant research interest in recent years. In our previous study (Stanimirova et al. Langmuir 2011, 27, 12486-12498), we showed that the triterpenoid saponins extracted from Quillaja saponaria plant (Quillaja saponins) formed adsorption layers with unusually high surface dilatational elasticity, 280 ± 30 mN/m. In this Article, we study the shear rheological properties of the adsorption layers of Quillaja saponins. In addition, we study the surface shear rheological properties of Yucca saponins, which are of steroid type. The experimental results show that the adsorption layers of Yucca saponins exhibit purely viscous rheological response, even at the lowest shear stress applied, whereas the adsorption layers of Quillaja saponins behave like a viscoelastic two-dimensional body. For Quillaja saponins, a single master curve describes the data for the viscoelastic creep compliance versus deformation time, up to a certain critical value of the applied shear stress. Above this value, the layer compliance increases, and the adsorption layers eventually transform into viscous ones. The experimental creep-recovery curves for the viscoelastic layers are fitted very well by compound Voigt rheological model. The obtained results are discussed from the viewpoint of the layer structure and the possible molecular mechanisms, governing the rheological response of the saponin adsorption layers. PMID:22830458

Golemanov, Konstantin; Tcholakova, Slavka; Denkov, Nikolai; Pelan, Edward; Stoyanov, Simeon D

2012-08-21

234

Rheology of surface granular flows  

Science.gov (United States)

Surface granular flow, comprising granular material flowing on the surface of a heap of the same material, occurs in several industrial and natural systems. The rheology of such a flow was investigated by means of measurements of velocity and number-density profiles in a quasi-two-dimensional rotating cylinder, half-filled with a model granular material monosize spherical stainless-steel particles. The measurements were made at the centre of the cylinder, where the flow is fully developed, using streakline photography and image analysis. The stress profile was computed from the number-density profile using a force balance which takes into account wall friction. Mean-velocity and root-mean-square (r.m.s.)-velocity profiles are reported for different particle sizes and cylinder rotation speeds. The profiles for the mean velocity superimpose when distance is scaled by the particle diameter d and velocity by a characteristic shear rate dot{gamma}_C = [gsin(beta_m-beta_s)/dcosbeta_s](1/2) and the particle diameter, where beta_m is the maximum dynamic angle of repose and beta_s is the static angle of repose. The maximum dynamic angle of repose is found to vary with the local flow rate. The scaling is also found to work for the r.m.s. velocity profiles. The mean velocity is found to decay exponentially with depth in the bed, with decay length lambda=1.1d. The r.m.s. velocity shows similar behaviour but with lambda=1.7d. The r.m.s. velocity profile shows two regimes: near the free surface the r.m.s. velocity is nearly constant and below a transition point it decays linearly with depth. The shear rate, obtained by numerical differentiation of the velocity profile, is not constant anywhere in the layer and has a maximum which occurs at the same depth as the transition in the r.m.s. velocity profile. Above the transition point the velocity distributions are Gaussian and below the transition point the velocity distributions gradually approach a Poisson distribution. The shear stress increases roughly linearly with depth. The variation in the apparent viscosity eta with r.m.s. velocity u shows a relatively sharp transition at the shear-rate maximum, and in the region below this point the apparent viscosity eta˜ u(-1.5) . The measurements indicate that the flow comprises two layers: an upper low-viscosity layer with a nearly constant r.m.s. velocity and a lower layer of increasing viscosity with a decreasing r.m.s. velocity. The thickness of the upper layer depends on the local flow rate and is independent of particle diameter while the reverse is found to hold for the lower-layer thickness. The experimental data is compared with the predictions of three models for granular flow.

Orpe, Ashish V.; Khakhar, D. V.

235

Characteristics of tantalum electrolytic capacitors using soluble polypyrrole electrolyte  

Science.gov (United States)

Polypyrrole (Ppy) electrolyte solutions in various organic solvents (dimethylformamide, DMF; N-methyl-2-pyrrolidone, NMP; chloroform; trifluoroacetic acid) were prepared using Ppy powder doped with di(2-ethylhexyl)sulfosuccinate sodium salt (Ppy-DEHS) and butylnaphthalene sulfonate sodium salt (Ppy-BNS), respectively. Several tantalum electrolytic capacitors were fabricated by dip coating in these solutions and their electrical properties such as capacitance and tan ? were measured. The capacitors prepared with Ppy-DEHS electrolyte in trifluoroacetic acid showed both high capacitance and low tan ?. Usage of a Ppy electrolyte solution containing both surfactant and a coupling agent also resulted in high capacitance and low tan ?. These phenomena were interpreted in terms of electrical conductivity and chemical structure of the electrolyte, and interactions such as hydrogen bonding, radical addition reaction, covalent bonding between the tantalum oxide layer and the solvent.

Jang, Kwan Sik; Moon, Bongjin; Oh, Eung Ju; Lee, Hoosung

236

Norbornene-Based Polymer Electrolytes for Lithium Cells  

Science.gov (United States)

Norbornene-based polymers have shown promise as solid electrolytes for lithium-based rechargeable electrochemical cells. These polymers are characterized as single-ion conductors. Single-ion-conducting polymers that can be used in lithium cells have long been sought. Single-ion conductors are preferred to multiple-ion conductors as solid electrolytes because concentration gradients associated with multiple-ion conduction lead to concentration polarization. By minimizing concentration polarization, one can enhance charge and discharge rates. Norbornene sulfonic acid esters have been synthesized by a ring-opening metathesis polymerization technique, using ruthenium-based catalysts. The resulting polymer structures (see figure) include sulfonate ionomers attached to the backbones of the polymer molecules. These molecules are single-ion conductors in that they conduct mobile Li+ ions only; the SO3 anions in these polymers, being tethered to the backbones, do not contribute to ionic conduction. This molecular system is especially attractive in that it is highly amenable to modification through functionalization of the backbone or copolymerization with various monomers. Polymers of this type have been blended with poly(ethylene oxide) to lend mechanical integrity to free-standing films, and the films have been fabricated into solid polymer electrolytes. These electrolytes have been demonstrated to exhibit conductivity of 2 10(exp -5)S/cm (which is high, relative to the conductivities of other solid electrolytes) at ambient temperature, plus acceptably high stability. This type of norbornene-based polymeric solid electrolyte is in the early stages of development. Inasmuch as the method of synthesis of these polymers is inherently flexible and techniques for the fabrication of the polymers into solid electrolytes are amenable to optimization, there is reason to anticipate further improvements.

Cheung, Iris; Smart, Marshall; Prakash, Surya; Miyazawa, Akira; Hu, Jinbo

2007-01-01

237

Physical and chemical characteristics of electrolytes based on lithium bis(oxalate)borate for lithium batteries  

International Nuclear Information System (INIS)

The physical-chemical properties of lithium bis(oxalate)borate (LiBOB) synthesized by solid phase synthesis and the electrolytes based on it have been investigated. The experiments showed that the electrolytes based on LiBOB have high electrochemical stability and conductivity in a wide temperature range. It has been demonstrated that the LiBOB addition has a promising use in lithium and lithium-ion power sources.

238

Physics of Electrolytic Gas Evolution  

CERN Document Server

A brief analysis of the physics and effects of electrolytic gas evolution is presented. Aspects considered include bubble nucleation, growth, and detachment, enhancement of mass and heat transfer, and decrease of apparent electrical conductivity of bubble containing electrolytes. This analysis is mainly oriented to hydrogen/oxygen evolving electrodes.

Sequeira, Cesar A C; Sljukic, Biljana; Amaral, Luis

2013-01-01

239

Electrodecontamination using a basic electrolyte  

Energy Technology Data Exchange (ETDEWEB)

A decontamination procedure for stainless steel is described that has the following advantages: rapid decontamination, one minute of time to reach nonretrievable level; easy to separate contamination by filtration; contamination is easy to recover in nitric acid; the electrolyte has an extended life - can be reused; and the waste generated from spent electrolyte is compatible with Rocky Flats waste processing.

Childs, E. L.

1979-01-01

240

High Energy Density Electrolytic Capacitor  

Science.gov (United States)

A new type of electrolytic capacitor which combines an electrolytic capacitor anode with an electrochemical capacitor cathode was developed. The resulting capacitor has a four time higher energy density than standard electrolytic capacitors, with comparable electric performance. The prototype, a 480 microFarad, 200 V device, has an energy density exceeding 4 J/cc. Now a 680 microFarad 50 V, MIL-style all tantalum device has been constructed and is undergoing qualification testing. Pending a favorable outcome, work will begin on other ratings. The potential for commercially significant development exists in applying this technology to aluminum-based electrolytic capacitors. It is possible to at least double the energy density of aluminum electrolytics, while using existing manufacturing methods, and without adding material expense. Data presented include electrical characteristics and performance measurements of the 200 V and 50 V hybrid capacitors and results from ongoing qualification testing of the MIL-style tantalum capacitors.

Evans, David A.

1996-01-01

 
 
 
 
241

Electrolytes for rechargeable lithium batteries  

International Nuclear Information System (INIS)

There is growing interest in high specific energy lithium rechargeable batteries with improved discharge/charge cycles. Some of the promising battery systems under development are Li/CoO2, Li/V2O5 and Li/MnO2. A major factor that controls the specific performance of these batteries is the electrolyte. Recent advances made in the liquid electrolyte area for lithium high energy cathode systems are reviewed. Experimental work on the processing of solid thin film polymer electrolytes using plasticizers such as polyethylene glycol dimethoxy ether (PEGDME) and the properties such as conductivity and differential scanning calorimetry of polymer film electrolytes are presented. The advantages and the disadvantages of polymer thin film electrolytes are discussed

242

Perovskite solid electrolytes for SOFC  

International Nuclear Information System (INIS)

The object of this program is to experimentally determine the utility of selected perovskite related solid electrolytes for application in SOFC's operating at intermediate temperatures (600-750 degrees C). Specific technical objectives addressed in this program include: Gaining useful insight into those crystallographic and thermodynamic parameters which influence both activation energy (Ea) for ionic transport and the population of ionic charge carriers. Synthesizing selected perovskite related solid electrolyte powders expected to possess (i) low Ea for ionic conduction and (ii) an intrinsically high population of ionic charge carriers. Preparing sintered solid electrolyte disks and determine their ionic conductivity. Incorporating solid electrolytes demonstrating acceptable ionic conductivity into small research size SOFC's operating at intermediate temperatures and determine their electrochemical performance. Determining the long-term stability of selected solid electrolyte materials incorporated into SOFC'S

243

Role of Yield Stress in Magma Rheology  

Science.gov (United States)

Magmas are essentially multiphase material composed of solid crystals, gaseous bubbles and silicate liquids. They exhibit various types of drastic change in rheology with variation of mutual volumetric fractions of the components. The nature of this variable rheology is a key factor in controlling dynamics of flowing magma through a conduit. Particularly the existence of yield stress in flowing magma is expected to control the wall friction and formation of density waves. As the volumetric fraction of solid phase increases yield stress emerges above the critical fraction. Several previous studies have been conducted to clarify this critical value of magmatic fluid both in numerical simulations and laboratory experiments ([Lejeune and Pascal, 1995], [Saar and Manga 2001], [Ishibashi and Sato 2010]). The obtained values range from 13.3 to 40 vol%, which display wide variation and associated change in rheology has not been clarified well. In this presentation we report physical mechanism of emergence of yield stress in suspension as well as the associated change in the rheology based on laboratory experiments using analog material. We utilized thermogel aqueous suspension as an analog material of multiphase magma. Thermogel, which is a commercial name for poly(N-isopropyl acrylamide) (PNIPAM) undergoes volumetric phase change at the temperature around 35C:below this temperature the gel phase absorbs water and swells while below this it expels water and its volume shrinks. Because of this the volumetric fraction of gel phase systematically changes with temperature and the concentration of gel powder. The viscosity measured at lower stress drastically decreases across this phase change with increasing temperature while the viscosity at higher stress does not exhibit large change across the transition. We have performed a series of rheological measurements focusing on the emergence of yield stress on this aqueous suspension. Since the definition of yield stress is not well defined in the suspension rheology we tested three types of measurement in determination of yield stress. Two methods utilized cone-plate geometry performing creep test (stress controlled) and variable shear rate test and one utilized narrow-gap concentric cylinder geometry with variable shear rate. Herschel-Bulckley model can be successfully applied to variable shear-rate tests to determine yield stress. Creep test and H-B model give almost identical yield stress, for instance 45±5Pa at 2.5wt%. At the gel volume fraction of 50% yield stress emerges and it increases with the increase of the concentration of gel powder. This critical value roughly corresponds to the random loose packing fraction while the viscosity begins to increase at lower fraction.

Kurokawa, A.; Di Giuseppe, E.; Davaille, A.; Kurita, K.

2012-04-01

244

Electrolyte paste for molten carbonate fuel cells  

Science.gov (United States)

The electrolyte matrix and electrolyte reservoir plates in a molten carbonate fuel cell power plant stack are filled with electrolyte by applying a paste of dry electrolyte powder entrained in a dissipatable carrier to the reactant flow channels in the current collector plate. The stack plates are preformed and solidified to final operating condition so that they are self sustaining and can be disposed one atop the other to form the power plant stack. Packing the reactant flow channels with the electrolyte paste allows the use of thinner electrode plates, particularly on the anode side of the cells. The use of the packed electrolyte paste provides sufficient electrolyte to fill the matrix and to entrain excess electrolyte in the electrode plates, which also serve as excess electrolyte reservoirs. When the stack is heated up to operating temperatures, the electrolyte in the paste melts, the carrier vaporizes, or chemically decomposes, and the melted electrolyte is absorbed into the matrix and electrode plates.

Bregoli, Lawrance J. (Southwick, MA); Pearson, Mark L. (New London, CT)

1995-01-01

245

Rheological behaviour of heated potato starch dispersions  

Science.gov (United States)

The study was designed to investigate the rheological properties of heated potato starch dispersions. Water suspensions of starch were heated at 65, 80 or 95°C for 5, 15, 30 or 60 min. The dispersions obtained were examined for granule size distribution and rheology. It was found that the starch dispersions significantly differed in both respects. The mean diameters of starch granules were largest for the dispersion heated at 65°C and smallest for that heated at 95°C. As the heating temperature was raised, the yield stresses and consistency coefficients decreased, while the flow behaviour indexes and Casson plastic viscosities increased. There were also differences in the viscoelastic properties of the dispersions: for those heated at 65°C the storage and loss moduli increased with heating time whereas for those heated at 80°C both moduli decreased.

Juszczak, L.; Witczak, M.; Ziêba, T.; Fortuna, T.

2012-10-01

246

Rheology dynamics of aggregating colloidal suspensions.  

Science.gov (United States)

We study a colloidal model based on population balances in the context of complex fluid rheology. Two typical particle microstructure kinetics, orthokinetic, collisions due to shear, and perikinetic, collisions due to Brownian motion, are found to appear at continuum as different flow behaviors - those having monotonic and non-monotonic flow curves, respectively. Solving the colloidal model together with the 1D Stokes equation for laminar, incompressible flow with Couette boundary conditions, allows bridging the gap between the rheological experiments and the microstructural modeling. The analysis of such a model reveals that orthokinetic particle suspensions have a uniquely defined, continuous steady state shear profile, whereas suspensions in which also perikinetic collisions are present, the steady state can be shear banded and non-unique. Thus, the shear banded configurations at a steady state are found to depend on the initial conditions and the collision kinetics of the system. At high shear rates all the studied cases show continuous shear profiles. PMID:24695455

Mohtaschemi, Mikael; Puisto, Antti; Illa, Xavier; Alava, Mikko J

2014-05-01

247

Rheology of a confined granular material  

CERN Document Server

We study the rheology of a granular material slowly driven in a confined geometry. The motion is characterized by a steady sliding with a resistance force increasing with the driving velocity and the surrounding relative humidity. For lower driving velocities a transition to stick-slip motion occurs, exhibiting a blocking enhancement whith decreasing velocity. We propose a model to explain this behavior pointing out the leading role of friction properties between the grains and the container's boundary.

Ovarlez, G; Clément, E; Ovarlez, Guillaume; Kolb, Evelyne; Cl\\'{e}ment, Eric

2001-01-01

248

Continuous measurement of materials rheology and hardness  

International Nuclear Information System (INIS)

Method for continuous measurement of materials rheology and hardness is based on multifunctional piezoelectric converters, in which both direct and inverse piezoelectric effects are used in combination with spatial control of three-dimensional oscillations, is presented. The method can be implemented by scanning the surface of any highly loaded part of a shaft, propeller or any friction surface by means of a special transducer. The scanning could be done by a robot, a coordinate measuring machine or a special positioning device. (orig.)

249

THERMOPHYSICAL AND RHEOLOGIC PROPERTIES OF BIOOIL SAMPLES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article deals with thermal properties of selected biooils Plahyd S biooil No1 and Plahyd N biooil No2 and rheologic properties of rapeseed oil. Plahyd S is a synthetic, rapidly biodegradable fluid which is based on sustainable raw materials. It is exceptionally suitable for applications in mobile and stationary hydraulic systems. Plahyd N is multigrade hydraulic oil based on rapeseed oil used in agricultural and construction machinery. For thermal parameters measurements was used Hot wir...

Monika Bozikova; Peter Hlavac

2013-01-01

250

Rheology Modifiers for Radioactive Waste Slurries  

International Nuclear Information System (INIS)

The goals of this study were to determine if trace levels of chemical additives could be used to reduce the rheological characteristics of radioactive waste slurries, identify potential chemical additives for this work and future testing, test a limited set of chemical additive candidates on simulated radioactive wastes, and develop advanced techniques to visualize the internal slurry structure and particle-particle interaction within the slurry

251

Rheology and structure of milk protein gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent studies on gel formation and rheology of milk gels are reviewed. A distinction is made between gels formed by aggregated casein, gels of `pure` whey proteins and gels in which both casein and whey proteins contribute to their properties. For casein' whey protein mixtures, it has been shown that both the fraction whey protein aggregated with the casein particles and whey protein aggregates dispersed in the continuous phase have a large impact on the structural and mechanical properties ...

Vliet, T.; Lakemond, C. M. M.; Visschers, R. W.

2004-01-01

252

Rheology of Active-Particle Suspensions  

CERN Document Server

We study the interplay of activity, order and flow through a set of coarse-grained equations governing the hydrodynamic velocity, concentration and stress fields in a suspension of active, energy-dissipating particles. We make several predictions for the rheology of such systems, which can be tested on bacterial suspensions, cell extracts with motors and filaments, or artificial machines in a fluid. The phenomena of cytoplasmic streaming, elastotaxis and active mechanosensing find natural explanations within our model.

Hatwalne, Y; Rao, M; Simha, R A; Hatwalne, Yashodhan; Ramaswamy, Sriram; Rao, Madan

2004-01-01

253

The rheology of a bubbly liquid.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A semiempirical constitutive model for the visco-elastic rheology of bubble suspensions with gas volume fractions &phis; < 0.5 and small deformations (Ca << 1) is developed. The model has its theoretical foundation in a physical analysis of dilute emulsions. The constitutive equation takes the form of a linear Jeffreys model involving observable material parameters: the viscosity of the continuous phase, gas volume fraction, the relaxation time, bubble size distribution and an empirically det...

Llewellin, E. W.; Mader, H. M.; Wilson, S. D. R.

2002-01-01

254

Relaxation and Rheology in Dense Athermal Suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study relaxation and rheology of dense athermal suspensions of frictionless particles close below the jamming density. Our key quantity, the relaxation time---determined from the exponential decay of the energy after the shearing has suddenly been switched off---is argued to be a determining factor behind the algebraic divergence of various quantities as the jamming density is approached from below. We also define and measure the ``dissipation time'', which is obtained di...

Olsson, Peter

2013-01-01

255

Rheology of Dense Sheared Granular Liquids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rheology of dense sheared granular liquids is investigated based on the mode-coupling theory (MCT). This extended MCT includes correlations for the density-current mode as well as the density-density correlation mode, and a self-consistent coupling equation for the energy balance condition. The extended MCT exhibits disappearance of the two-step relaxation of the density-density correlation function, and also successfully reproduces the density dependence of the shear vi...

Suzuki, Koshiro; Hayakawa, Hisao

2013-01-01

256

Density functional approach to nonlinear rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a density functional based closure of the pair Smoluchowski equation for Brownian particles under shear flow. Given an equilibrium free energy functional as input the theory provides first-principles predictions for the flow-distorted pair correlation function and associated rheological quantities over a wide range of volume fractions and flow rates. Taking two-dimensional hard-disks under shear flow as an illustrative model we calculate the pair correlation funct...

Reinhardt, Johannes; Weysser, F.; Brader, Joseph M.

2013-01-01

257

From Reactor to Rheology in LDPE Modeling  

International Nuclear Information System (INIS)

In recent years the association between molecular structure and linear rheology has been established and well-understood through the tube concept and its extensions for well-characterized materials (e.g. McLeish, Adv. Phys. 2002). However, for industrial branched polymeric material at processing conditions this piece of information is missing. A large number of phenomenological models have been developed to describe the nonlinear response of polymers. But none of these models takes into account the underlying molecular structure, leading to a fitting procedure with arbitrary fitting parameters. The goal of applied molecular rheology is a predictive scheme that runs in its entirety from the molecular structure from the reactor to the non-linear rheology of the resin. In our approach, we use a model for the industrial reactor to explicitly generate the molecular structure ensemble of LDPE's, (Tobita, J. Polym. Sci. B 2001), which are consistent with the analytical information. We calculate the linear rheology of the LDPE ensemble with the use of a tube model for branched polymers (Das et al., J. Rheol. 2006). We then, separate the contribution of the stress decay to a large number of pompom modes (McLeish et al., J. Rheol. 1998 and Inkson et al., J. Rheol. 1999) with the stretch time and the priority variables corresponding to the actual ensemble of molecules involved. This multimode pompom model allows us to predict the nonlinear properties without any fitting parametear properties without any fitting parameter. We present and analyze our results in comparison with experimental data on industrial materials

258

Rheology, and how to stop aging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent analytical developments in glass theory are equally relevant to the understanding of anomalous rheology, with characteristic features such as the Reynolds dilatancy and the driving-power dependence of the viscosity arising naturally. A notion of effective temperature based on the fluctuation-dissipation relation can be introduced in the limit of small driving power. Within mean-field, the analogue of the Edwards compactivity can be computed, and it coincides with this...

Kurchan, Jorge

1998-01-01

259

Crust rheology, slab detachment and topography  

Science.gov (United States)

The collision between continents following the closure of an ocean can lead to the subduction of continental crust. The introduction of buoyant crust within subduction zones triggers the development of extensional stresses in slabs which eventually result in their detachment. The dynamic consequences of slab detachment affects the development of topography, the exhumation of high-pressure rocks and the geodynamic evolution of collision zones. We employ two-dimensional thermo-mechanical modelling in order to study the importance of crustal rheology on the evolution of spontaneous subduction-collision systems and the occurrence of slab detachment. The modelling results indicate that varying the rheological structure of the crust can results in a broad range of collisional evolutions involving slab detachment, delamination (associated to slab rollback), or the combination of both mechanisms. By enhancing mechanical coupling at the Moho, a strong crust leads to the deep subduction of the crust (180 km). These collisions are subjected to slab detachment and subsequent coherent exhumation of the crust accommodated by eduction (inversion of subduction sense) and thrusting. In these conditions, slab detachment promotes the development of a high (> 4.5 km) and narrow (detachment to occur. Further shortening leads to buckling and thickening of the crust resulting in the development of topographic bulging on the lower plate. Collisions involving rheologically layered crust are characterised by a decoupling level at mid-crustal depths. These initial condition favours the delamination of the upper crust as well as the deep subduction of the lower crust. These collisions are thus successively affected by delamination and slab detachment and both processes contribute to the exhumation of the subducted crust. A wide (> 200 km) topographic plateau develops as the results of the buoyant extrusion of the upper crust onto the foreland, this mechanism is further amplified by slab detachment. Our results suggest that the occurrence of both delamination (Apennines) and slab detachment (Himalayas) in orogens may highlight significant differences in their initial rheological structure.

Duretz, T.; Gerya, T. V.

2012-04-01

260

Rheological properties of dairy cattle manure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheological properties are important for the design and modelling of handling and treating fluids. In the present study, the viscosity of liquid manure (about 10% total solids) was measured at different shear rates (2.38¿238 s¿1). The effect of temperature on the viscosity at different shear rates was also studied. The results showed that manure has non-Newtonian flow properties, because the viscosity strongly depended on the applied shear rate. The results showed also that manure behaves l...

El-mashad, H. M.; Loon, W. K. P.; Zeeman, G.; Bot, G. P. A.; Lettinga, G.

2005-01-01

 
 
 
 
261

Charge relaxation dynamics of an electrolytic nanocapacitor  

CERN Document Server

Understanding ion relaxation dynamics in overlapping electric double layers (EDLs) is critical for the development of efficient nanotechnology based electrochemical energy storage, electrochemomechanical energy conversion and bioelectrochemical sensing devices besides controlled synthesis of nanostructured materials. Here, using Lattice Boltzmann (LB) method, we present results from the simulations of an electrolytic nanocapacitor subjected to a step potential at t = 0 for various degrees of EDL overlap, solvent viscosities, ratios of cation to anion diffusivity and electrode separations. A continuously varying molecular speed dependent relaxation time, proposed for use with the LB equation, recovers the correct microscopic description of molecular collision phenomena and holds promise for enhancing the stability of the LB algorithm. Results for large EDL overlap showed oscillatory behavior for ionic current densities in contrast to monotonic relaxation to equilibrium for low EDL overlap. Further, at low solv...

Thakore, Vaibhav

2013-01-01

262

Cyclic Macromolecules: Dynamics and Nonlinear Rheology, Final Report DOE Award # DE-FG02-05ER46218, Texas Tech University  

Energy Technology Data Exchange (ETDEWEB)

The work described in the present report had the original goal to produce large, entangled, ring polymers that were uncontaminated by linear chains and to characterize by rheological methods the dynamics of these rings. While the work fell short of this specific goal, the outcomes of the research performed under support from this grant provided novel macromolecular synthesis methods, new separation methods for ring and linear chains, and novel rheological data on bottle brush polymers, wedge polymers and dendron-based ring molecules. The grant funded a total of 8 archival manuscripts and one patent, all of which are attached to the present report.

McKenna, Gregory B.; Grubbs, Robert H.; Kornfield, Julia A.

2012-04-25

263

Rheological Characterization of Shale – Mud Interactions  

Directory of Open Access Journals (Sweden)

Full Text Available

In a bid to identify a best drilling fluid for a problematic oil field in the Niger Delta region, rheological tests were carried out on three mud samples; BW1, BW3 and BW4. The results affirm that the load bearing capacity of XP-07 formulated as BW3 and BW4 in this investigation is excellent and fall within the same range or even better than those of REF Mud with a more than 90% drilling success history in Niger Delta. The rheological changes of XP-07 with increase in temperature and “assimilated” microscopic shale particles are very negligible and smaller than those of REF mud. XP-07 has been strongly recommended for all drilling operations in the problematic field. It has been re-emphasised as part of our recommendations that new guidelines for the close monitoring of drilling fluids supplied by mud companies and those actually used in the field (during drilling be put in place.

Key words: Shale – mud interactions; Rheological characterization; Niger delta

W. O. Emofurieta

2012-03-01

264

Electro-rheological finishing for optical surfaces  

Science.gov (United States)

Many polishing techniques such as fixed-abrasive polishing, abrasive-free polishing and magnetorheological finishing etc., have been developed. Meanwhile, a new technique is proposed using the mixture of the electro-rheological (Er) fluid with abrasives as polishing slurry, which is a special process does not require pad. Electrorheological fluid is a special suspension liquid, whose viscosity has an approximate proportional relation with the electric strength applied. When the field strength reaches a certain limit, the phase transition occurs and the liquid acquires a solid like character, and while the electric field is removed, the fluid regains its original viscosity during the order of milliseconds. In this research work, we employed the characteristics of viscosity change of Er fluid to hold the polishing particles for micromachining. A point-contact electro-rheological finishing (Erf) tool was designed with a tip diameter 0.5~1mm. Both the anode and the cathode of the electric field were combined in the tool. The electric field could be controllable. When the tool moves across the profile of the work piece, by controlling the electric field strength as well as the other manufacturing parameters we can assure the deterministic material removal. Furthermore, the electro-rheological finishing process has been planned in detailed.

Cheng, Haobo; Wang, Peng

2009-05-01

265

Structure and rheology of organoclay suspensions  

International Nuclear Information System (INIS)

We have characterized a montmorillonite-based organoclay dispersed in three different nonaqueous solvents using a combination of x-ray scattering, small-angle neutron scattering (SANS), and ultrasmall angle neutron scattering (USANS), together with rheological measurements. Consistent with these measurements, we present a structural model for the incompletely dispersed clay as consisting of randomly oriented tactoids made of partially overlapping clay sheets, with transverse dimensions of several microns. Intersheet correlation peaks are visible in x-ray scattering, and quantitatively fit by our model structure factor. SANS and USANS together show a power law of about -3 over a wide range of wave numbers below the intersheet correlation peak. Our model relates this power law to a power law distribution of the number of locally overlapping layers in a tactoid. The rheology data show that both storage and loss moduli, as well as yield stress, scale with a power law in volume fraction of about three. Equating the gel onset composition with the overlap of randomly oriented tactoids and taking into account the large transverse dimensions of the tactoids, we predict the gel point to be at or below 0.006 volume fraction organoclay. This is consistent with the rheology data

266

Rheological models applied to wheat and corn dough  

Directory of Open Access Journals (Sweden)

Full Text Available Rheological models of a food system are useful for simulating a material’s response to an applied stress or strain and for predicting the effect of composition and processing conditions. Rheological models can be applied when experimental data is expressed in fundamental units. This article describes two rheological models used for studying wheat and corn dough: the biaxial extensional model and the oscillatory dynamic model. The results of research related to this topic are also reported.

Eduardo Rodríguez Sandoval

2010-04-01

267

Rheological Behavior Analysis of Liver Fibrosis in Rats  

Directory of Open Access Journals (Sweden)

Full Text Available The process of liver fibrosis changes rheological properties of tissue. This study characterizes and compares two stages of liver fibrosis in rats. Two rheological models—Voigt model and Zener model are applied to the measured data. The experimental results demonstrate that Zener model is preferred to Voigt model for describing rheological properties of liver fibrosis stages F0 and F2 in rats.

Ying Zhu

2013-05-01

268

Bubble suspension rheology and implications for conduit flow.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bubbles are ubiquitous in magma during eruption and influence the rheology of the suspension. Despite this, bubble-suspension rheology is routinely ignored in conduit-flow and eruption models, potentially impairing accuracy and resulting in the loss of important phenomenological richness. The omission is due, in part, to a historical confusion in the literature concerning the effect of bubbles on the rheology of a liquid. This confusion has now been largely resolved and recently published stu...

Llewellin, E. W.; Manga, M.

2005-01-01

269

Lithium ion conducting ionic electrolytes  

Science.gov (United States)

A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100 C or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors. 4 figs.

Angell, C.A.; Xu, K.; Liu, C.

1996-01-16

270

Photopolymerized Electrolytes For Electrochromic Devices  

Science.gov (United States)

Thin ion-conducting electrolyte films for use in electrochromic devices now fabricated relatively easily and quickly with any of class of improved formulations containing ultraviolet-polymerizable components. Formulations are liquids in their monomeric forms and self-supporting, transparent solids in their polymeric forms. Thin solid electrolytes form quickly and easily between electrode-bearing substrates. Film thus polymerized acts not only as solid electrolyte but also as glue holding laminate together: feature simplifies fabrication by reducing need for sealants and additional mechanical supports.

Cogan, Stuart; Rauh, R. David

1994-01-01

271

Development of Alternative Rheological Measurements for DWPF Slurry Samples  

International Nuclear Information System (INIS)

of rheological measurement methods used to characterize DWPF slurry samples. The organization is by rheological measurement method. Progress on the first two goals was documented in a concurrent technical report, Koopman (2005). That report focused on the types and possible causes of unusual rheological behavior in simulant slurry samples. It was organized by the sample being studied. The experimental portion of this study was performed in the period of March to April 2004. A general rheology protocol for routine DWPF slurry samples, Koopman (2004b), was drafted in addition to the companion technical report to this document

272

Post-seismic stress relaxation with a linear transient rheology  

Directory of Open Access Journals (Sweden)

Full Text Available We performed an analysis of post-seismic stress relaxation, taking into account generalized linear rheologies. We compared the stress field (and its derived functions obtained with a classical Maxwell rheology with that obtained with a transient Burgers body. From a set of synthetic case studies, we have revealed quantitative and qualitative differences both in relaxation times and in local stress values when a transient rheology is introduced. As a practical application, we modeled the time evolution of the Coulomb failure function following the 2009 L'Aquila earthquake, and we show that a transient rheology can lead to non-monotonic time dependence.

Antonio Piersanti

2010-05-01

273

Review Of Rheology Modifiers For Hanford Waste  

International Nuclear Information System (INIS)

As part of Savannah River National Laboratory (SRNL)'s strategic development scope for the Department of Energy - Office of River Protection (DOE-ORP) Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste feed acceptance and product qualification scope, the SRNL has been requested to recommend candidate rheology modifiers to be evaluated to adjust slurry properties in the Hanford Tank Farm. SRNL has performed extensive testing of rheology modifiers for use with Defense Waste Processing Facility (DWPF) simulated melter feed - a high undissolved solids (UDS) mixture of simulated Savannah River Site (SRS) Tank Farm sludge, nitric and formic acids, and glass frit. A much smaller set of evaluations with Hanford simulated waste have also been completed. This report summarizes past work and recommends modifiers for further evaluation with Hanford simulated wastes followed by verification with actual waste samples. Based on the review of available data, a few compounds/systems appear to hold the most promise. For all types of evaluated simulated wastes (caustic Handford tank waste and DWPF processing samples with pH ranging from slightly acidic to slightly caustic), polyacrylic acid had positive impacts on rheology. Citric acid also showed improvement in yield stress on a wide variety of samples. It is recommended that both polyacrylic acid and citric acid be further evaluated as rheology modifiers for Hanford waste. These materials are weak organic acids with the following potential issues: The acidic nature of the modifiers may impact waste pH, if added in very large doses. If pH is significantly reduced by the modifier addition, dissolution of UDS and increased corrosion of tanks, piping, pumps, and other process equipment could occur. Smaller shifts in pH could reduce aluminum solubility, which would be expected to increase the yield stress of the sludge. Therefore, it is expected that use of an acidic modifier would be limited to concentrations that do not appreciably change the pH of the waste; Organics are typically reductants and could impact glass REDOX if not accounted for in the reductant addition calculations; Stability of the modifiers in a caustic, radioactive environment is not known, but some of the modifiers tested were specifically designed to withstand caustic conditions; These acids will add to the total organic carbon content of the wastes. Radiolytic decomposition of the acids could result in organic and hydrogen gas generation. These potential impacts must be addressed in future studies with simulants representative of real waste and finally with tests using actual waste based on the rheology differences seen between SRS simulants and actual waste. The only non-organic modifier evaluated was sodium metasilicate. Further evaluation of this modifier is recommended if a reducing modifier is a concern

274

Method of cadmium electrolytic deposition  

International Nuclear Information System (INIS)

A new method for cadmium electrolytic deposition from sulphate electrolytes at the presence of surface-active substances (SAS) is suggested. The method differs from the earlier known ones; it presupposes use of primary aliphatic alcohols, namely, methanol or ethanol at the quantity of 0.5-2.5 mass% as surface-active substances for increase of cadmium current efficiency and decrease of power consumption. The invention concerns nonferrous metallurgy. It may be applied for cadmium electrolytic preparation from sulphate electrolytes. Methanol and ethanol are shown to produce similar effect as SAS in cadmium electrolysis. Thus, they may be used in a mixture but not as separate components. The advantage of the suggested method is that it ensures reduction of power consumption by 200-250 kWxh/t and increase of current efficiency by 3-5% that is essential for large-scale cadmium production

275

Lithium organic liquid electrolyte batteries  

Science.gov (United States)

The application of organic electrolytes to primary and secondary Li batteries for terrestrial and space uses is examined. It is required that the organic liquid electrolytes be stable in the presence of Li and the cathode, operate over a wide temperature range, and have high specific conductance. The factors that are relevant to solvent properties, which include dielectric constant, viscosity, and electron donor number, are analyzed; the conductivity of the organic solution LiAsF6 is studied. The effect of Li surface film formation on the stability of liquid electrolyte batteries is investigated. The solvent-salt requirements for electrolytes of secondary batteries are described; the use of an ether/LiAsF6 solution in secondary batteries is discussed.

Abraham, K. M.

276

Composite solid polymer electrolyte membranes  

Science.gov (United States)

The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

Formato, Richard M. (Shrewsbury, MA); Kovar, Robert F. (Wrentham, MA); Osenar, Paul (Watertown, MA); Landrau, Nelson (Marlborough, MA); Rubin, Leslie S. (Newton, MA)

2001-06-19

277

Synthesis and characterization of La0.9Sr0.1Ga0.8Mg0.2O3-? intermediate-temperature electrolyte using conventional solid state reaction  

Science.gov (United States)

The perovskite-type La0.9Sr0.1Ga0.8Mg0.2O3-?(LSGM9182) with high oxygen-ionic conductivity is successfully synthesized using conventional solid-state reaction. The phase composition, grain size distribution, relative density, and oxygen-ionic conductivity of the samples are studied. The XRD result shows that the main perovskite LaGaO3 phase can be produced at 1,250 °C, with trace amount of second phase LaSrGaO4. When the temperature increases to 1,400 °C, the pure phase LSGM can be obtained. The relative density of LSGM pellets sintered at 1,400 °C reaches 98.08%. The average grain size of final powders is ?0.12 ?m, which is appropriate for the deposition of LSGM electrolyte film. The ideal oxygen-ionic conductivities of 0.04, 0.06, and 0.08 S cm-1 can be obtained at 700 °C, 750 °C, and 800 °C, respectively. Porous anode supported single cells with LSGM electrolyte film are fabricated using the as-prepared LSGM powders and the cells provide an open-circuit voltage of above 1.0 V, revealing that the LSGM film is gas-tight and crack-free.

Li, Minxia; Zhang, Yaohui; An, Maozhong; Lü, Zhe; Huang, Xiqiang; Xiao, Juncheng; Wei, Bo; Zhu, Xingbao; Su, Wenhui

2012-11-01

278

Solid polymer electrolyte lithium batteries  

Science.gov (United States)

This invention pertains to Lithium batteries using Li ion (Li.sup.+) conductive solid polymer electrolytes composed of solvates of Li salts immobilized in a solid organic polymer matrix. In particular, this invention relates to Li batteries using solid polymer electrolytes derived by immobilizing solvates formed between a Li salt and an aprotic organic solvent (or mixture of such solvents) in poly(vinyl chloride).

Alamgir, Mohamed (Dedham, MA); Abraham, Kuzhikalail M. (Needham, MA)

1993-01-01

279

Feeding electrolyte for sport horses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays is necessary to have a multidisciplinary approach to the horse, to find the key for the optimal performance not only by considering macronutriens such as protein, fat and sugar, but also minerals such as electrolyte. The electrolytes include minerals such as Sodium (Na), Potassium (K) Chloride (Cl), Calcium (Ca) and Magnesium (Mg), that when dissolved in a appropriate solvent are ionized and conduct an electric current. In the body ions are dissolved in three main compartments: the ...

Bergero, Domenico; Valle, Emanuela

2008-01-01

280

Ionic liquids as electrolytes  

International Nuclear Information System (INIS)

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batn in aluminium electroplating, lithium batteries and in electrochemical capacitors

 
 
 
 
281

Ionic liquids as electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors. (author)

Galinski, Maciej; Lewandowski, Andrzej; Stepniak, Izabela [Faculty of Chemical Technology, Poznan University of Technology, PL-60 965 Poznan (Poland)

2006-08-15

282

Hectorite-based nanocomposite electrolytes for lithium-ion batteries  

Science.gov (United States)

Hectorite clay is presented in this work as a promising component for electrolytes for lithium-ion batteries. This negatively-charged, plate-shaped (250 nm diameter by 1 nm thickness) clay has exchangeable cations for which lithium may be substituted. When properly dispersed in high-dielectric solvents such as the carbonates (ethylene carbonate and propylene carbonate) typically used in lithium-ion cells, a shear-thinning physical gel is created possessing a good conductivity (as high as 2 x 10-4 S/cm at room temperature has been measured) with near unity lithium-ion transference numbers. As a result, hectorite-based electrolytes could drastically reduce concentration polarization and present an inherently safer electrolyte as toxic salts such as LiPF6 that are typically used could be eliminated. Hectorite clay dispersions in aqueous and non-aqueous (1:1 (v:v) ethylene carbonate: poly(ethylene)glycol dimethyl ether 250 MW) solvents have been studied using rheology (dynamic and steady) and conductivity. The aqueous dispersions show a highly-exfoliated microstructure (fractal dimension, Df ? 1.6) created primarily through electrostatic repulsive forces which recovers after shear deformation by reorientation of the clay platelets. The non-aqueous dispersions form gel structures with a much higher degree of aggregation (Df ? 2.5), and recovery after shear deformation appears to be an aggregation controlled process as well. TEM imaging of non-aqueous clay dispersions shows the clay to be uniformly distributed, with the platelets existing in aggregates of 3 to 5 layers. Use of the hectorite-based electrolytes in lithium-ion cells requires electrodes that contain a single-ion conductor in the typically porous structures. Cathodes based on LiCoO2 that contain various lithium-conducting species (lithium hectorite, lithium LaponiteRTM, and lithium-exchanged NAFIONRTM) have been studied. AC impedance spectroscopy was used to probe the cells and equivalent circuits were used to model the physical processes that occur. Cathodes containing 4 wt. % lithium hectorite + 3 wt. lithium-exchanged NAFIONRTM + 3 wt. % carbon black exhibit capacities approximately 90 mAh/g LiCoO2. These hectorite-based electrolytes and clay-containing cathodes are potentially attractive for use in single-ion conducting lithium-ion batteries designed for high-discharge applications.

Riley, Michael William

283

Effective rheology of partially molten rocks: Numerical and experimental data  

Science.gov (United States)

We analyze the mechanical and rheological behavior of a two-phase system consisting of rigid grains and an interconnecting viscous fluid. For this purpose we use 2D direct numerical finite element simulations on the spatial scale of individual grains. We derived expressions for the effective viscosity for both Newtonian and non-Newtonian rheologies. Simulations using instantaneous deformation demonstrate that the effective rheology of the assemblage is non-Newtonian only if the fluid has a non-Newtonian rheology. At low fluid fractions the strain rates within the fluid are locally up to three orders of magnitude higher than the overall applied background strain rate. This may explain experimentally observed Newtonian to non-Newtonian rheological transitions. Laboratory experimental studies indicate that melt-grain systems behave non-linearly for moderate to high strain rates. However, the relative importance of shear heating, non-linear rheology, elasticity, plasticity and finite strain of the assemblage remains to be examined and may influence the effective rheology in a counter-intuitive manner. We have developed a 0D visco-elastic inversion model, which allows us to extract the effective rheological parameters from both numerical and laboratory experiments. We test the model against a series of 2D finite strain grain-scale numerical simulations. The rheology of each phase is controlled independently. Rheologies can be either linear or non-linear visco-elastic and the viscosity can be either temperature and composition dependent or independent. The simulations also account for shear heating. The 0D model reproduces well the rheological parameters (viscosity, temperature, elastic shear modulus) for the synthetic models. From this success we conclude that the model can be used to extract rheological information from laboratory data. Simulations with realistic grain shapes and linear visco-elastic rheology show no evidence that grain rearrangement causes a change to non-linear aggregate rheology. Thermal effects for strain rates <10-3 s-1 are too small to induce significant shear heating. However, realistic grain shapes do cause higher local stresses compared to regular grain shapes, e.g. spherical grains. Higher stresses enhance plastic failure, which aids in turn to locally reduce the viscosity. Such a process may additionally induce non-linear behaviour of the melt-grain system. The new findings can be applied to laboratory experiments on the effective rheology of partially molten rocks and have implications for volcanic eruptions and batholith emplacement.

Deubelbeiss, Yolanda; Kaus, Boris J. P.; Connolly, James A. D.

2010-05-01

284

Rheological Properties of Aqueous Nanometric Alumina Suspensions  

Energy Technology Data Exchange (ETDEWEB)

Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the {sup 17}O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles' surfaces in the aqueous suspension. The viscosity of the suspension increases dramatically when the solid volume fraction exceeds 30 vol.%. The overlap of physically adsorbed water layers at this level causes the sharp increase in viscosity. Fructose molecules can weaken the interactions between the particle surfaces and water molecules, as a consequence, they release some bound water layers from the surfaces to the bulk medium. It is believed that fraction of the water that is bound by the solid surface is reduced hence becoming available for flow. The oxygen-17 relaxation time decreased with the increase of particle volume fractions in the suspension. Fructose addition increased the overall water mobility in the suspension. Only part of the alumina particle surfaces was covered with fructose molecules. This adsorption of fructose molecules on the particle surfaces increased the pH of the suspension with a concomitant decrease in {zeta}-potential of the alumina nanoparticles. The interactions between the nanometric alumina particles in water to a large extent can be explained by the DLVO theory. However, the interactions between particles in fructose solutions cannot be well described by the DLVO theory. The interaction forces (magnitude and range) as well as adhesive force and surface tension between nanometric alumina particles were decreased with the fructose concentration.

Chuanping Li

2004-12-19

285

The rheological behavior of HDPE/coal blends  

Energy Technology Data Exchange (ETDEWEB)

The antistatic functional material of HDPE/coal [high density polyethylene mixed with coal fines] has a higher tensile strength, higher resistance and stability. The rheological properties of the blends are important for their processing and practical use. It was necessary to study the rheological behavior of the blends. P. Ujas et al (1994) had studied the rheology of HDPE/nylon-11 blends and the effect of nylon-11 on the rheological behavior of HDPE. If Shenfu coal is used as a special polymer, it has necessarily an important affect on the rheological behavior of HDPE. In this paper, the rheological behavior of HDPE/coal blends were investigated to study the effect of the coal polymer on the rheology of HDPE. The rheological behavior of the blends were found to be very different from that of HDPE. The curves of shear viscosity for the blends at different temperatures (478, 488, and 498K) reveal that HDPE and the blends are characteristic of pseudoplastic fluid, that is, there is a decrease of shear viscosity with an increase of shearing rate.

Zhou Anning; Ge Lingmei [Xi`an Mining Inst. (China). Dept. of New Material Engineering; Guo Shucai [Dalian Univ. of Technology (China)

1997-12-31

286

Concentration Dependence of Rheological Properties of Telechelic Associative Polymer Solutions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We consider concentration dependence of rheological properties of associative telechelic polymer solutions. Experimental results for model telechelic polymer solutions show rather strong concentration dependence of rheological properties. For solutions with relatively high concentrations, linear viscoelasticity deviates from the single Maxwell behavior. The concentration dependence of characteristic relaxation time and moduli is different in high and low concentration cases....

Uneyama, Takashi; Suzuki, Shinya; Watanabe, Hiroshi

2012-01-01

287

Electrolytic phase transformation actuators  

Science.gov (United States)

The emerging field of materials-based actuation continues to be the focus of considerable research due to its inherent scalability and its promise to drive devices in ways that cannot be realized with conventional mechanical actuator strategies. Current approaches include electrochemically responsive conducting polymers, capacitance-driven carbon nanotubes actuators, pH responsive hydrogels, ionic polymer metal composites, electric field responsive elastomers, and field-driven electrostrictive polymers. However, simple electrochemical processes that lead to phase transformations, particularly from liquid to gas, have been virtually ignored. Although a few specialized applications have been proposed, the nature of the reactions and their implication for design, performance, and widespread applicability have not been addressed. Herein we report an electrolytic phase transformation (EPT) actuator, a device capable of producing strains surpassing 136,000% and stresses beyond 200 MPa. These performance characteristics are several orders of magnitude greater than those reported for other materials and could potentially compete with existing commercial hydraulic systems. Furthermore, unlike other materials-based systems that rely on bimorph structures to translate infinitesimally small volume changes into observable deflections, this device can direct all of its output towards linear motion. We show here that an unoptimized actuator prototype can produce volume and pressure changes close to the theoretically predicted values, with maximum stress (70 kPa) limited only by the mechanical strength of the apparatus. Expansion is very rapid and scales with applied current density. Retraction depends on the catalytic nature of the electrode, and state-of-the-art commercial fuel cell electrodes should allow rates surpassing 0.9 mL's-1.cm-2 and 370 kPa's-1.cm-2. We anticipate that this approach will provide a new direction for producing scalable, low-weight, high performance actuators that will be useful in a broad range of applications.

Cameron, Colin G.; Freund, Michael S.

2003-07-01

288

Stress- and rate-controlled granular rheology  

Science.gov (United States)

Granular solid hydrodynamics (GSH) is employed to account for granular rheology, both the rate-controlled one, smoothly extending from the critical state to the Bagnold regime, and the stress-controlled one that is discontinuous and hysteretic. Employing GSH, it is shown that a quiescent state is stable below the smaller jamming stress and instable above the larger fluidization stress, with values in between being metastable; also, that the MiDi relation, appropriate for rigid grains, needs to be rectified, because real granular media, with a sound velocity one to three times that of air, are soft.

Jiang, Yimin; Liu, Mario

2013-06-01

289

Rheology of nearly ideal 3d foams  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We probe the complex rheology of nearly ideal 3d foam by flowing through a narrow column. The foams we investigate have large bubble size, to minimize the effects of coarsening, and are very dry. Foams of this type cannot be studied via conventional rheometry. The foam flows upward through a vertical rectangular column with a 4:1 cross-sectional aspect ratio, by bubbling gas through a soapy solution at the base of our apparatus. At the column's narrow surfaces are sticky bou...

Jones, C. D.; Nordstrom, K. N.; Durian, D. J.

2014-01-01

290

Mass Transfer and Rheology of Fiber Suspensions  

Science.gov (United States)

Rheological and mass transfer properties of non-Brownian fiber suspensions are affected by fiber characteristics, fiber interactions, and processing conditions. In this thesis we develop several simulation methods to study the dynamics of single fibers in simple shear flow, as well as the rheology and mass transfer of fiber suspensions. Isolated, rigid, neutrally-buoyant, non-Brownian, slightly curved, nonchiral fibers in simple shear flow of an incompressible Newtonian fluid at low Reynolds number can drift steadily in the gradient direction without external forces or torques. The average drift velocity and direction depend on the fiber aspect ratio, curvature and initial orientation. The drift results from the coupling of rotational and translational dynamics, and the combined effects of flipping, scooping, and spinning motions of the fiber. Irreversible fiber collisions in the suspensions cause shear-induced diffusion. The shear-induced self-diffusivity of dilute suspensions of fibers increases with increasing concentration and increasing static friction between contacts. The diffusivities in both the gradient and vorticity directions are larger for suspensions of curved fibers than for suspensions of straight fibers. For suspensions of curved fibers, significant enhancements in the diffusivity in the gradient direction are attributed to fiber drift in the gradient direction. The shear-induced self-diffusivity of concentrated suspensions of fibers increases with increasing concentration before fiber networks or flocs are formed, after which the diffusivity decreases with increasing concentration. The diffusivity increases with increasing fiber equilibrium bending angle, effective stiffness, coefficient of static friction, and rate of collisions. The specific viscosity of fiber suspensions increases with increasing fiber curvature, friction coefficient between mechanical contacts, and solids concentration. The specific viscosity increases linearly with concentration in the dilute regime, and increases with the cube of the concentration in the semi-dilute regime. Concentrated fiber suspensions are highly viscous, shear thinning, and exhibit significant yield stresses and normal stress differences. Yield stresses scale with volume concentration and fiber aspect ratio in the same way as that observed in experiments. The first normal stress difference increases linearly with shear rate. The shear-induced diffusivity increases linearly with the derivative of the particle contribution to stress for dilute suspensions with respective to concentration. This correlation between rheology and shear-induced diffusion makes it possible to predict diffusivity from easily measured rheological properties.

Wang, Jianghui

291

Rheology of spinel sludge in molten glass  

International Nuclear Information System (INIS)

Spinel sludge, which forms while vitrifying high-level waste, obstructs the flow of molten glass and damages the melter. The effectiveness of removing spinel sludge from a high-level waste glass melter depends on its rheological behavior. We prepared spinel sludge in a laboratory crucible by allowing spinel to settle from molten glass and measured the response of the sludge to shear using a rotating spindle viscometer. The shear stress increased nonlinearly with the velocity gradient (the shear rate) and with time at a constant velocity gradient, as is typical for a pseudoplastic rheopectic liquid. The apparent viscosity of the sludge substantially increased when RuO-2 needles were present

292

Rheological and phase behaviour of amphiphilic lipids  

Directory of Open Access Journals (Sweden)

Full Text Available This chapter reviews the different association structures which are likely to be formed by amphiphilic lipids in the liquid-crystalline state and their corresponding shear flow properties. The structure and rheological behaviour of thermotropic liquid crystals, emphasizing the properties of smectic mesophases, and those of lyotropic liquid crystals such as: nematic, lamellar, diluted lamellar, lamellar dispersions, hexagonal and cubic mesophases are described. The importance of a comprehensive rheological characterisation, including rheo-optical techniques, is pointed out for their practical applications, development of formulations and as a useful technique to assist in the determination of phase diagrams. A historical approach has been used to discuss the evolving field of the rheology and structure identification of liquid crystals formed by amphiphilic lipids and surfactants. Non-Newtonian viscous shear flow, thixotropic and antithixotropic phenomena, linear viscoelastic properties -described by dynamic and creep compliance experiments- and non-linear viscoelastic properties - described by the difference of normal stresses and stress relaxation tests are interpreted on the basis of a microstructure-rheology relationship. The polycrystalline nature of liquid crystals turns out to be rather sensitive to shear due to the change of both size and orientation of the liquid-crystalline monodomains under flow.En este capítulo se realiza una revisión de las distintas estructuras coloidales de asociación que pueden formar los lípidos anfifílicos en estado líquido-cristalino y de sus correspondientes propiedades de flujo en cizalla. Se describe la estructura y comportamiento reológico de cristales líquidos termotrópicos, con énfasis en los de tipo esméctico, fases gel, y cristales líquidos liotrópicos: nemáticos, laminares, laminares diluidos, dispersiones de laminares, hexagonales y cúbicos. Se hace hincapié en la importancia de una buena caracterización reológica y reo-óptica de cara a sus aplicaciones prácticas, desarrollo de formulaciones y como una técnica útil para determinar diagramas de fases y detectar cambios de estructura. Se ha usado una metodología histórica para analizar la evolución de la caracterización reológica e identificación de las diferentes estructuras líquido-cristalinas y estructuras afines. La interpretación de comportamientos de flujo viscoso no newtonianos, fenómenos tixotrópicos y antitixotrópicos y de las propiedades viscoelásticas lineales, determinadas con ensayos dinámicos y de fluencia, y no lineales, descritas mediante la diferencia de esfuerzos normales y ensayos de relajación del esfuerzo, se basa en la interrelación microestructuracomportamiento reológico. La naturaleza policristalina de los cristales líquidos resulta ser muy sensible a la cizalla, debido al cambio de tamaño y orientación de los dominios líquidocristalinos mientras fluyen.

Alfaro, M. C.

2000-04-01

293

Melt rheology and its applications in the plastics industry  

CERN Document Server

This is the second edition of Melt Rheology and its Role in Plastics Processing, although the title has changed to reflect its broadened scope. Advances in the recent years in rheometer technology and polymer science have greatly enhanced the usefulness of rheology in the plastics industry. It is now possible to design polymers having specific molecular structures and to predict the flow properties of melts having those structures. In addition, rheological properties now provide more precise information about molecular structure. This book provides all the information that is needed for the intelligent application of rheology in the development of new polymers, the determination of molecular structure and the correlation of processability with laboratory test data. Theory and equations are limited to what is essential for the use of rheology in the characterization of polymers, the development of new plastics materials and the prediction of plastics processing behavior. The emphasis is on information that wil...

Dealy, John M

2013-01-01

294

Rheological model and flow equation for elasto-viscoplastic mixtures ????????????? ?????? ? ????????? ??????? ??????-?????-?????????? ?????  

Directory of Open Access Journals (Sweden)

Full Text Available Advanced building materials technologies widely employ polymers. Viscoelastic and viscoplastic mixtures are used in the manufacturing of building materials and finishing products. Rheology studies deformation and flow patterns of different bodies.Markus Reiner developed mathematical formulations for rheological flows of viscous and plastic materials, processes of deformation of different bodies, behaviour of materials exposed to strain loads.A rheological flow of any material depends on deformation. Integrated analysis of linear deformations and strain is used to identify a relative change in the volume of an elasto-viscoplastic body. The flow of materials depends on their physicochemical properties. The flow of an elastic-viscous-plastic mixture in channels demonstrates its viscoelastic properties. Rheological equation of Oldroyd is used to relate strain to speed of displacement and the time of relaxation. The flow of polymeric materials is examined using Bingham’s rheological model.?????????? ??????? ????????? ?????????? ??????-?????-??????????? ?????????. ?????????? ???????????????? ????????? ???????? ? ????????????? ? ?????? ??????? ??????????, ??????? ?????????? ???????? ??????????? ????????? ????. ???????? ??????????? ??? ??????????? ?????????????? ????????? ?????? ??????-?????-????????????? ???? ??? ???????? ??????????. ?????????? ??????????? ?????????? ???????? ?????????????? ???????? ???? ?? ??????? ?????????? ??????????. ????????? ??????-?????-?????????? ????? ??????????? ?? ??????? ????????????? ?????? ???? ???????.

Luk’yanov Nikolai Andreevich

2013-05-01

295

Development of Alternative Rheological Measurements for DWPF Slurry Samples (U)  

Energy Technology Data Exchange (ETDEWEB)

Rheological measurements are used to evaluate the fluid dynamic behavior of Defense Waste Processing Facility, DWPF, slurry samples. Measurements are currently made on non-radioactive simulant slurries using two state-of-the-art rheometers located at the Aiken County Technical Laboratory, ACTL. Measurements are made on plant samples using a rheometer in the Savannah River National Laboratory, SRNL, Shielded Cells facility. Low activity simulants or plant samples can be analyzed using a rheometer located in a radioactive hood in SRNL. Variations in the rheology of SB2 simulants impacted the interpretation of results obtained in a number of related studies. A separate rheological study was initiated with the following four goals: (1) Document the variations seen in the simulant slurries, both by a review of recent data, and by a search for similar samples for further study. (2) Attempt to explain the variations in rheological behavior, or, failing that, reduce the number of possible causes. In particular, to empirically check for rheometer-related variations. (3) Exploit the additional capabilities of the rheometers by developing new measurement methods to study the simulant rheological properties in new ways. (4) Formalize the rheological measurement process for DWPF-related samples into a series of protocols. This report focuses on the third and fourth goals. The emphasis of this report is on the development and formalization of rheological measurement methods used to characterize DWPF slurry samples. The organization is by rheological measurement method. Progress on the first two goals was documented in a concurrent technical report, Koopman (2005). That report focused on the types and possible causes of unusual rheological behavior in simulant slurry samples. It was organized by the sample being studied. The experimental portion of this study was performed in the period of March to April 2004. A general rheology protocol for routine DWPF slurry samples, Koopman (2004b), was drafted in addition to the companion technical report to this document.

Koopman, D. c.

2005-09-01

296

Preparation of poly(acrylonitrile-butyl acrylate) gel electrolyte for lithium-ion batteries  

International Nuclear Information System (INIS)

Poly(acrylonitrile-butyl acrylate) gel polymer electrolyte was prepared for lithium ion batteries. The preparation started with synthesis of poly(acrylonitrile-butyl acrylate) by radical emulsion polymerization, followed by phase inversion to produce microporous membrane. Then, the microporous gel polymer electrolytes (MGPEs) was prepared with the microporous membrane and LiPF6 in ethylene carbonate/diethyl carbonate. The dry microporous membrane showed a fracture strength as high as 18.98 MPa. As-prepared gel polymer electrolytes presented ionic conductivity in excess of 3.0 x 10-3 S cm-1 at ambient temperature and a decomposition voltage over 6.6 V. The results showed that the as-prepared gel polymer electrolytes were promising materials for Li-ion batteries

297

Optimizing end-group cross-linking polymer electrolytes for fuel cell applications  

Energy Technology Data Exchange (ETDEWEB)

This paper demonstrates the optimization of proton conductivity and water uptake for cross-linkable polymer electrolytes through synthesis and characterization of end-group cross-linkable sulfonated poly(arylene ether) copolymers (ESF-BPs). The extent of reaction of cross-linking was controlled by reaction time resulting in a series of polymers with two, independent tunable parameters, degree of sulfonation (DS) and degree of cross-linking (DC). For the polymers presented, cross-linking improved proton conductivity while reducing water uptake, an uncommon trend in polymer electrolytes where water is critical for proton conduction. Other trends relating to changes are reported and the results yield insight into the role of DS and DC and how to optimize electrochemical properties and performance of polymer electrolytes through these tunable parameters. Select polymer electrolytes were tested in fuel cells where performance and durability with accelerated relative humidity cycling were compared with Nafion{reg_sign}.

Kim, Yu Seung [Los Alamos National Laboratory; Lee, Kwan Soo [Los Alamos National Laboratory; Jeong, Myung - Hwan [GIST, KOREA; Lee, Jae - Suk [GIST, KOREA

2009-01-01

298

The sodium sulfur battery system: Investigation of the solid electrolyte beta alumina  

Science.gov (United States)

Optimization procedures for the synthesis of beta alumina electrolyte ceramics are treated. Solid phases organized in the microstructure of the electrolyte and the corresponding stability of the ceramics against atmospheric attacks of H2O and CO2 were investigated. Thermoanalytical and X-ray diffraction studies of MgO- and Li2O-stabilized beta alumina samples demonstrate severe problems in the technological approach to synthesize pure MgO stabilized electrolyte ceramics of compositions 1Na2O.1MgO.5Al2O3 due Na2MgAl10O17 Monophasic beta-alumina type ceramic has the highest stability against atmospheric attack by H2O and CO2. Small variations in stoichiometry or in the temperature/time program of synthesis induce unwanted phases.

Felsche, J.

1983-06-01

299

Supercapacitor behavior of ?-MnMoO4 nanorods on different electrolytes  

International Nuclear Information System (INIS)

Graphical abstract: SEM image of ?-MnMoO4 nanorods on FTO substrate. Highlights: ? Synthesis of ?-MnMoO4 nanorods by spin coating method. ? First study on the effect of electrolyte on the pseudocapacitance behavior. ? ?-MnMoO4 nanorods exhibit maximum specific capacitance of 998 F/g. ? At higher scan rates p-TSA electrolyte exhibits superior capacitive behavior. -- Abstract: ?-MnMoO4 nanorods were prepared on conducting glass substrate via sol–gel spin coating method at the optimum doping level. The effect of electrolyte on the pseudocapacitance behavior of the ?-MnMoO4 nanorods was studied using para toluene sulfonic acid (p-TSA), sulfuric acid (H2SO4) and hydrochloric acid (HCl) as electrolytes. X-ray diffraction analysis reveals the formation of ?-MnMoO4 in monoclinic phase. FTIR spectra contain vibrational bands associated with Mo=O, M–O and Mo–O–Mo bonds. SEM image reveals the formation of nanorods. Supercapacitor behavior has been studied using cyclic voltammetry (CV) analysis. ?-MnMoO4 nanorods exhibit maximum specific capacitance of 998 F/g at a scan rate of 5 mV/s in H2SO4 electrolyte while a specific capacitance of 784 F/g and 530 F/g have been obtained using p-TSA and HCl electrolytes, respectively. At higher scan rates p-TSA electrolyte exhibits superior capacitive behavior than H2SO4.

300

Novel method for the preparation of uranium complexes via electrolytic amalgamation  

International Nuclear Information System (INIS)

Thermal degradiation of an electrolytically produced uranium amalgam produces a highly active metal powder which has been used in the synthesis of (1) uranium bis(cyclooctatetraene), (2) uranium tris(cyclopentadienyl), (3) uranium trifluoro-acetylacetonate. IR spectra and NMR spectral shifts were used for structural determinations. 1 table

 
 
 
 
301

Rheological Behavior of Schizophyllan in Fermentation System  

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Full Text Available Schizophyllan is a neutral extracellular polysaccharide produced by the fungus Schizophyllum commune, consisting of a 1,3--D-linked backbone of glucose residues with 1,6--D-glucosyl side groups. The polysaccharide rheological properties have been studied in the fermentation aqueous media over the time period of 168 h. The rheology of the schizophyllan produced by Schizophyllum commune NRCM isolated during the 168 h fermentation is also studied by determining the consistency index, K and flow behavior index, n of the fermentation broth and isolated schizophyllan samples. For measurement of intrinsic viscosity, [?], the viscosity was determined at 25C, at low polymer concentration and at low shear rate range. Schizophyllan biopolymer dispersion obeyed Power Law Model. Fermentation broth showed Newtonian behavior up to 96 h of fermentation time, beyond which the flow behavior was pseudoplastic. The molecular weight of schizophyllan was found to be 5.54 x105 Daltons after 168 h fermentation using Mark-Houwink relation.

Rekha S. Singhal

2011-01-01

302

Rheology and microstructure of concentrated suspensions  

International Nuclear Information System (INIS)

This paper gives an overview of some of the experiments currently underway to study the coupling of the microstructure and rheology of concentrated suspensions. Nuclear magnetic resonance imaging, real-time x-ray radiography, and refractive index matching allow the viewing of particles in concentrated suspensions. Both shear flow experiments and falling ball rheometry are reviewed. In the slow flow of these suspensions of large, hard, particles in a viscous Newtonian fluid, colloidal forces are negligible and hydrodynamic forces dominate. Large local concentration changes are shown to occur rapidly in suspensions of uniform spheres subjected to flow between concentric rotating cylinders. Suspensions of spheres with a bimodal size distribution not only show similar phenomena, but also exhibit particle separation according to size. In addition, the large particles in the bimodal suspension migrate into ordered, concentric, cylindrical sheets, parallel to the axis of the cylinders. These sheets of particles rotate relative to each other. The particle migration and structure formation induced by this inhomogeneous shear flow is believed to be responsible for torque reductions and other anomalous behavior witnessed during the rheological testing of concentrated suspensions reported in the literature. Thus, suspensions may not always be characterized by a viscosity that is a scalar material property

303

Rheology of rock glaciers: a preliminary assessment  

Energy Technology Data Exchange (ETDEWEB)

Movement of rock debris under the influence of gravity, i.e., mass movement, generates a range of phenomena from soil creep, through solifluction,debris flows and rock glaciers to rock falls. Whereas the resultant forms of these phenomena are different, common elements in the mechanics of movement are utilized in the basic interpretation of the processes of formation. Measurements of morphologic variables provide data for deductive analyses of processes that operate too slowly to observe or for processes that generated relict phenomena. External and internal characteristics or rock glacier morphometry and measured rates of motion serve as the basis for the development of a rheological model to explain phenomena classified as rock glaciers. A rock glacier in the Sangre de Cristo Mountains of Southern Colorado, which exhibits a large number of ridges and furrows and lichen bare fronts of lobes, suggests present day movement. A strain-net established on the surface provides evidence of movement characteristics. These data plus morphologic and fabric data suggest two rheological models to explain the flow of this rock glacier. Model one is based upon perfect plastic flow and model two is based upon stratified fluid movement with viscosity changing with depth. These models permit a better understanding of the movement mechanics and demonstrate that catastrophic events and slow creep contribute to the morphologic characteristics of this rock glacier.

Giardino, J.R.; Vitek, J.D.; Hoskins, E.R.

1985-01-01

304

Microstructure and rheology of lime putty.  

Science.gov (United States)

The rheology of lime binders, which is critical in the final performance of lime mortars and plasters, is poorly understood, particularly in its relationship with the microstructure and colloidal characteristics of slaked lime (Ca(OH)(2)) suspensions (i.e., lime putties). Here, the contrasting flow behavior of lime putties obtained upon slaking (hydration) of soft and hard burnt quicklimes (CaO) is compared and discussed in terms of the differences found in particle size, morphology, degree of aggregation, and fractal nature of aggregates as well as their evolution with aging time. We show that lime putties behave as non-Newtonian fluids, with thixotropic and rheopectic behavior observed for hard and soft burnt limes, respectively. Aggregation of portlandite nanoparticles in the aqueous suspension controls the time evolution of the rheological properties of lime putty, which is also influenced by the dominant slaking mechanism, that is, liquid versus vapor slaking in hard and soft burnt quicklimes, respectively. These results may be of relevance in the selection of optimal procedures and conditions for the preparation of lime mortars used in the conservation of historical buildings. PMID:19916534

Ruiz-Agudo, E; Rodriguez-Navarro, C

2010-03-16

305

Shear rheology of a cell monolayer  

International Nuclear Information System (INIS)

We report a systematic investigation of the mechanical properties of fibroblast cells using a novel cell monolayer rheology (CMR) technique. The new technique provides quantitative rheological parameters averaged over ?106 cells making the experiments highly reproducible. Using this method, we are able to explore a broad range of cell responses not accessible using other present day techniques. We perform harmonic oscillation experiments and step shear or step stress experiments to reveal different viscoelastic regimes. The evolution of the live cells under externally imposed cyclic loading and unloading is also studied. Remarkably, the initially nonlinear response becomes linear at long timescales as well as at large amplitudes. Within the explored rates, nonlinear behaviour is only revealed by the effect of a nonzero average stress on the response to small, fast deformations. When the cell cytoskeletal crosslinks are made permanent using a fixing agent, the large amplitude linear response disappears and the cells exhibit a stress stiffening response instead. This result shows that the dynamic nature of the cross-links and/or filaments is responsible for the linear stress-strain response seen under large deformations. We rule out the involvement of myosin motors in this using the inhibitor drug blebbistatin. These experiments provide a broad framework for understanding the mechanical responses of the cortical actin cytoskeleton of fibroblasts to differen cytoskeleton of fibroblasts to different imposed mechanical stimuli

306

Vortex jamming in superconductors and granular rheology  

International Nuclear Information System (INIS)

We demonstrate that a highly frustrated anisotropic Josephson junction array (JJA) on a square lattice exhibits a zero-temperature jamming transition, which shares much in common with those in granular systems. Anisotropy of the Josephson couplings along the horizontal and vertical directions plays roles similar to normal load or density in granular systems. We studied numerically static and dynamic response of the system against shear, i.e. injection of external electric current at zero temperature. Current-voltage curves at various strength of the anisotropy exhibit universal scaling features around the jamming point much as do the flow curves in granular rheology, shear-stress versus shear-rate. It turns out that at zero temperature the jamming transition occurs right at the isotropic coupling and anisotropic JJA behaves as exotic fragile vortex matter: it behaves as a superconductor (vortex glass) in one direction, whereas it is a normal conductor (vortex liquid) in the other direction even at zero temperature. Furthermore, we find a variant of the theoretical model for the anisotropic JJA quantitatively reproduces universal master flow-curves of the granular systems. Our results suggest an unexpected common paradigm stretching over seemingly unrelated fields-the rheology of soft materials and superconductivity.

307

Grain-size sensitive rheology of orthopyroxene  

Science.gov (United States)

grain-size sensitive rheology of orthopyroxene is investigated using data from rheological and microstructural studies. A deformation mechanism map is constructed assuming that orthopyroxene deforms by two independent mechanisms: dislocation creep and diffusion creep. The field boundary between these mechanisms is defined using two approaches. First, experimental data from Lawlis (1998), which show a deviation from non-linear power law behavior at low stresses, are used to prescribe the location of the field boundary. Second, a new orthopyroxene grain-size piezometer is used as a microstructural constraint to the field boundary. At constant temperature, both approaches yield sub-parallel field boundaries, separated in grain size by a factor of only 2-5. Extrapolating to lithospheric conditions, the deformation mechanism transition occurs at a grain size of ~150-500 µm, consistent with observations from nature. As the transition from dislocation to diffusion creep may promote shear localization, grain-size reduction of orthopyroxene may play a prominent role in plate-boundary deformation.

Bruijn, Rolf H. C.; Skemer, Philip

2014-07-01

308

Rheological changes in irradiated chicken eggs  

International Nuclear Information System (INIS)

Pathogenic bacteria may cause foodborne illnesses. Humans may introduce pathogens into foods during production, processing, distribution and or preparation. Some of these microorganisms are able to survive conventional preservation treatments. Heat pasteurization, which is a well established and satisfactory means of decontamination/disinfection of liquid foods, cannot efficiently achieve a similar objective for solid foods. Extensive work carried out worldwide has shown that irradiation is efficient in eradicating foodborne pathogens like Salmonella spp. that can contaminate poultry products. In this work Co-60 gamma irradiation was applied to samples of industrial powder white, yolk and whole egg at doses between 0 and 25 kGy. Samples were rehydrated and the viscosity measured in a Brookfield viscosimeter, model DV III at 5, 15 and 25 degree sign C. The rheological behaviour among the various kinds of samples were markedly different. Irradiation with doses up to 5 kGy, known to reduced bacterial contamination to non-detectable levels, showed almost no variation of viscosity of irradiated egg white samples. On the other hand, whole or yolk egg samples showed some changes in rheological properties depending on the dose level, showing the predominance of whether polimerization or degradation as a result of the irradiation. Additionally, irradiation of yolk egg powder reduced yolk color as a function of the irradiation exposure implemented. The importance of these resulimplemented. The importance of these results are discussed in terms of possible industrial applications

309

Rheological characterization of Poloxamer 407 nimesulide gels  

Directory of Open Access Journals (Sweden)

Full Text Available The thermal gelling property of Poloxamer 407- nimesulide gels was characterized by rheological studies. Nimesulide, a local anti-inflammatory and anesthetic drug used for the treatment of acute and chronic pain, has a short duration of action and a long-acting single-dose injection would be of clinical importance. Thus a poloxamer 407 gel applied intramuscularly could prolong the release and action of nimesulide. In this study, aqueous gels with nimesulide, containing three different concentrations of Poloxamer 407, were prepared. Viscosity measurements were performed by rheologial studies to obtain the optimal sol-gel transition temperature . Poloxamer 407 gels are pseudoplastic and viscoelastic materials, which have an elastic modulus (G', characteristic of the solid, and a viscous modulus (G'', characteristic of the liquid material. Moreover, being pseudoplastic gels, when they are deformed by shearing, their viscosity decreases. Increase of the polymer concentration increased the viscosity of the gels, which could affect the releasing process of nimesulide. Furthermore, the presence of nimesulide led to a lowering of the sol-gel transition temperature. Keywords: Poloxamer 407 gels; nimesulide; rheological characterization; viscosity; sol-gel transition temperature.

M. N. Freitas

2009-01-01

310

Anion exchange polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Solid anion exchange polymer electrolytes and compositions comprising chemical compounds comprising a polymeric core, a spacer A, and a guanidine base, wherein said chemical compound is uniformly dispersed in a suitable solvent and has the structure: ##STR00001## wherein: i) A is a spacer having the structure O, S, SO.sub.2, --NH--, --N(CH.sub.2).sub.n, wherein n=1-10, --(CH.sub.2).sub.n--CH.sub.3--, wherein n=1-10, SO.sub.2-Ph, CO-Ph, ##STR00002## wherein R.sub.5, R.sub.6, R.sub.7 and R.sub.8 each are independently --H, --NH.sub.2, F, Cl, Br, CN, or a C.sub.1-C.sub.6 alkyl group, or any combination of thereof; ii) R.sub.9, R.sub.10, R.sub.11, R.sub.12, or R.sub.13 each independently are --H, --CH.sub.3, --NH.sub.2, --NO, --CH.sub.nCH.sub.3 where n=1-6, HC.dbd.O--, NH.sub.2C.dbd.O--, --CH.sub.nCOOH where n=1-6, --(CH.sub.2).sub.n--C(NH.sub.2)--COOH where n=1-6, --CH--(COOH)--CH.sub.2--COOH, --CH.sub.2--CH(O--CH.sub.2CH.sub.3).sub.2, --(C.dbd.S)--NH.sub.2, --(C.dbd.NH)--N--(CH.sub.2).sub.nCH.sub.3, where n=0-6, --NH--(C.dbd.S)--SH, --CH.sub.2--(C.dbd.O)--O--C(CH.sub.3).sub.3, --O--(CH.sub.2).sub.n--CH--(NH.sub.2)--COOH, where n=1-6, --(CH.sub.2).sub.n--CH.dbd.CH wherein n=1-6, --(CH.sub.2).sub.n--CH--CN wherein n=1-6, an aromatic group such as a phenyl, benzyl, phenoxy, methylbenzyl, nitrogen-substituted benzyl or phenyl groups, a halide, or halide-substituted methyl groups; and iii) wherein the composition is suitable for use in a membrane electrode assembly.

Kim, Yu Seung; Kim, Dae Sik; Lee, Kwan-Soo

2013-07-23

311

Molten-salt synthesis of oxyapatite La{sub 9.33}Si{sub 6}O{sub 26} powders as electrolytes for intermediate temperature solid oxide fuel cells  

Energy Technology Data Exchange (ETDEWEB)

Lanthanum silicate oxy-apatites are thought of as ytrria-stabilized zirconia substitutes in intermediate temperature solid oxide fuel cells. Lanthanum silicate oxy-apatite powders La{sub 9.33}Si{sub 6}O{sub 26} are successfully synthesized at lower temperature by a molten-salt method. X-ray diffraction, scanning electron microscopy, and precision impedance analysis used to characterize the structure, appearance, and conductivity of La{sub 9.33}Si{sub 6}O{sub 26}. The results indicate that the apatite phase has been synthesized. The synthesis method decreases the synthesis temperature by about 300 C in comparison to the conventional solid-state reaction route and obtains homogeneous and nanosize powders. Dense ceramics have been prepared at sintering temperatures around 1450 C. The used of molten-salt powders allows a decrease of the dense ceramic pellet sintering temperature of about 200 C. The ceramic pellets sintering at 1550 C for 4 h have a relative density of 92% and an electrical conductivity of 1.1 x 10{sup -3} S cm{sup -1} at 700 C, higher than the some reported for the solid-state synthesis method and the sol-gel method. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Huang, Zhaoxiang [Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Wenhua College, Huazhong University of Science and Technology, Wuhan 430074 (China); Li, Buyin; Liu, Jia [Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

2010-10-15

312

Solution rheology of polyelectrolytes and polyelectrolyte-surfactant systems  

Science.gov (United States)

The fundamental understanding of polyelectrolytes in aqueous solutions is an important branch of polymer research. In this work, the rheological properties of polyelectrolytes and polyelectrolyte/surfactant systems are studied. Various synthetic poly electrolytes are chosen with varied hydrophobicity. We discuss the effects of adding various surfactants to aqueous solutions of poly(ethylene oxide)-b-poly(propylene oxide)- b-polyethylene oxide)-g-poly(acrylic acid) (PEO-PPO-PAA) in the first chapter. Thermogelation in aqueous solutions of PEO-PPO-PAA is due to micellization caused by aggregation of poly(propylene oxide) (PPO) blocks resulting from temperature-induced dehydration of PPO. When nonionic surfactants with hydrophilic-lipophilic balance (HLB) parameter exceeding 11 or Cn alkylsulfates; n-octyl (C8), n-decyl (C 10) and n-dodecyl (C12) sulfates are added, the gelation threshold temperature (Tgel) of 1.0wt% PEO-PPO-PAA in aqueous solutions increases. In contrast, when nonionic surfactants with HLB below 11 are added, the gelation temperature decreases. On the other hand, alkylsulfates with n = 16 or 18 and poly(ethylene oxide) (PEO) do not affect the Tgel. The results imply that both hydrophobicity and tail length of the added surfactant play important roles in the interaction of PEO-PPO-PAA micelles and the surfactant. In the second chapter, the solution behavior of alternating copolymers of maleic acid and hydrophobic monomer is studied. The alternating structure of monomers with two-carboxylic groups and hydrophobic monomers make these copolymers unique. Under appropriate conditions, these carboxylic groups dissociate leaving charges on the chain. The potentiometric titrations of copolymer solutions with added CaCl2 reveal two distinct dissociation processes corresponding to the dissociation of the two adjacent carboxylic acids. The viscosity data as a function of polymer concentration of poly(isobutylene-alt-sodium maleate), poly(styrene-alt-sodium maleate) and poly(diisobutylene- alt-sodium maleate) show the polyelectrolyte behavior as predicted. However, the viscosity as a function of concentration of sodium maleate based copolymers with 1-alkenes; 1-octene (C8), 1-decene (C10), 1-dodecene (C12) and 1-hexene (C14) exhibit an abnormal scaling power, which might be caused by aggregation of the alkene tails to form micelles. In the last chapter, we report the rheological properties of aqueous solutions of poly(acrylic acid) and oppositely charged surfactant, dodecyl trimethylammonium bromide (C12TAB). The solution viscosity decreases as surfactant is added, partly because the polyelectrolyte wraps around the surface of the spherical surfactant micelles, shortening the effective chain length. The effects of polymer molecular weight, polymer concentration, and polymer charge have been studied with no added salt. The results are compared with the predictions of a simple model based on the scaling theory for the viscosity of dilute and unentangled semidilute polyelectrolyte solutions in good solvent. This model takes into account two effects of added surfactant. The effective chain length of the polyelectrolyte is shortened when a significant fraction of the chain wraps around micelles. Another effect is the change of solution ionic strength resulting from surfactant addition that further lowers the viscosity. The parameters used in this model are independently determined, allowing the model to make a quantitative prediction of solution viscosity with no adjustable parameters. The model is also applied to predict the decrease in viscosity of various polyelectrolyte/oppositely charged surfactant systems reported in literature. The results are in good agreement with experimental data, proving that our model applies to all polyelectrolytes mixed with oppositely charged surfactants that form spherical micelles.

Plucktaveesak, Nopparat

313

The electrolyte challenge for a direct methanol-air polymer electrolyte fuel cell operating at temperatures up to 200 C  

Science.gov (United States)

Novel polymer electrolytes are being evaluated for use in a direct methanol-air fuel cell operating at temperatures in excess of 100 C. The evaluation includes tests of thermal stability, ionic conductivity, and vapor transport characteristics. The preliminary results obtained to date indicate that a high temperature polymer electrolyte fuel cell is feasible. For example, Nafion 117 when equilibrated with phosphoric acid has a conductivity of at least 0.4 Omega(exp -1)cm(exp -1) at temperatures up to 200 C in the presence of 400 torr of water vapor and methanol vapor cross over equivalent to 1 mA/cm(exp 2) under a one atmosphere methanol pressure differential at 135 C. Novel polymers are also showing similar encouraging results. The flexibility to modify and optimize the properties by custom synthesis of these novel polymers presents an exciting opportunity to develop an efficient and compact methanol fuel cell.

Savinell, Robert; Yeager, Ernest; Tryk, Donald; Landau, Uziel; Wainright, Jesse; Gervasio, Dominic; Cahan, Boris; Litt, Morton; Rogers, Charles; Scherson, Daniel

1993-01-01

314

Catalyzed electrolytic plutonium oxide dissolution  

International Nuclear Information System (INIS)

The principle, method and equipment of the catalyzed electrolytic plutonium oxide dissolution (CEPOD) are described. In the presence of small amount of catalyst (such as Ag+), PuO2 is oxidized into PuO22+ for dissolution by the electrolytic method. This method has the advantages of quick, thorough, batch dissolution and of working in the condition of near the environmental temperature, no adding of hydrofluoric acid (HF) and low acidity (HNO3), etc. It is fitted for dissolution of PuO2 which is prepared or calcined at high temperature (950-1700 degree C), for MOX spent fuel element, for leaching plutonium scrap and plutonium-contaminated waste and for electrolytic destroy about contaminated or deleterious waste, etc

315

Diabetes mellitus and electrolyte disorders.  

Science.gov (United States)

Diabetic patients frequently develop a constellation of electrolyte disorders. These disturbances are particularly common in decompensated diabetics, especially in the context of diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. These patients are markedly potassium-, magnesium- and phosphate-depleted. Diabetes mellitus (DM) is linked to both hypo- and hyper-natremia reflecting the coexistence of hyperglycemia-related mechanisms, which tend to change serum sodium to opposite directions. The most important causal factor of chronic hyperkalemia in diabetic individuals is the syndrome of hyporeninemic hypoaldosteronism. Impaired renal function, potassium-sparing drugs, hypertonicity and insulin deficiency are also involved in the development of hyperkalemia. This article provides an overview of the electrolyte disturbances occurring in DM and describes the underlying mechanisms. This insight should pave the way for pathophysiology-directed therapy, thus contributing to the avoidance of the several deleterious effects associated with electrolyte disorders and their treatment. PMID:25325058

Liamis, George; Liberopoulos, Evangelos; Barkas, Fotios; Elisaf, Moses

2014-10-16

316

High elastic modulus polymer electrolytes  

Science.gov (United States)

A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics.

Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel

2013-10-22

317

Hermetically Sealed Aluminum Electrolytic Capacitor  

Science.gov (United States)

Aluminum electrolytic capacitors are presently not allowed on NASA missions because they outgas water and organic vapors, as well as H2. As a consequence, for some applications, much larger and heavier packages of tantalum capacitors must be used. A hermetically sealed aluminum capacitor has been developed. This contains a nongassing electrolyte that was developed for this application so internal pressure would remain low. Capacitors rated from 250 V to 540 V have been operated under full load for thousands of hours at 85 and 105 C with good electrical performance and absence of gas generation. Electrolyte chemistry and seal engineering will be discussed, as well as the extension of this design concept to lower voltage ratings.

Alwitt, Robert S.; Liu, Yanming; Elias, William

1996-01-01

318

Towards Prognostics of Electrolytic Capacitors  

Science.gov (United States)

A remaining useful life prediction algorithm and degradation model for electrolytic capacitors is presented. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management research. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. In particular, experimental results of an accelerated aging test under electrical stresses are presented. The capacitors used in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors.

Celaya, Jose R.; Kulkarni, Chetan; Biswas, Gautam; Goegel, Kai

2011-01-01

319

Fuel cell electrolyte supply system and apparatus  

International Nuclear Information System (INIS)

A system and apparatus for supplying and circulating fresh electrolyte to and through the anode and ion exchange sections of a plurality of related air/metal fuel cells; preventing the flow of shunt currents through the electrolyte between the fuel cell sections; removing heat produced by fuel cell reaction from the electrolyte; removing solid by products of fuel cell reaction from the electrolyte; and reconstituting spent electrolyte. The system and apparatus commingles electrolyte with a hydrophobic liquid dielectric which has a specific gravity which is less than the specific gravity of the electrolyte and conducting the commingled liquids through small diameter conductors of dielectric material to the fuel cell sections. The liquid dielectric in the electrolytes and conductors maintain a current path in the electrolyte open and prevent the flow of shunt currents. The system and apparatus operate to separate commingled liquid dielectric and electrolyte flowing from the fuel cell sections; removed heat carried from the cell sections by the liquid dielectric; recommingles the liquid dielectric and electrolyte and reintroduces into the cell sections. The cell sections. The system and apparatus operate to intermittently transfer portions of partially spent byproduct ladened electrolyte circulated through the anode sections of the cells to a separator in which the byproduct is removed from the spent electrolyte

320

The effect of low-molecular-weight poly(ethylene glycol) (PEG) plasticizers on the transport properties of lithium fluorosulfonimide ionic melt electrolytes.  

Science.gov (United States)

The influence of low-molecular-weight poly(ethylene glycol) (PEG, Mw ? 550 Da) plasticizers on the rheology and ion-transport properties of fluorosulfonimide-based polyether ionic melt (IM) electrolytes has been investigated experimentally and via molecular dynamics (MD) simulations. Addition of PEG plasticizer to samples of IM electrolytes caused a decrease in electrolyte viscosity coupled to an increase in ionic conductivity. MD simulations revealed that addition of plasticizer increased self-diffusion coefficients for both cations and anions with the plasticizer being the fastest diffusing species. Application of a VTF model to fit variable-temperature conductivity and fluidity data shows that plasticization decreases the apparent activation energy (Ea) and pre-exponential factor A for ion transport and also for viscous flow. Increased ionic conductivity with plasticization is thought to reflect a combination of factors including lower viscosity and faster polyether chain segmental dynamics in the electrolyte, coupled with a change in the ion transport mechanism to favor ion solvation and transport by polyethers derived from the plasticizer. Current interrupt experiments with Li/electrolyte/Li cells revealed evidence for salt concentration polarization in electrolytes containing large amounts of plasticizer but not in electrolytes without added plasticizer. PMID:24773589

Geiculescu, Olt E; Hallac, Boutros B; Rajagopal, Rama V; Creager, Stephen E; DesMarteau, Darryl D; Borodin, Oleg; Smith, Grant D

2014-05-15

 
 
 
 
321

Effective dielectric constant of electrolytes  

Science.gov (United States)

We show that in the framework of the Poisson-Nernst-Planck model, where the ions are assumed point-like particles, the dielectric constant of the electrolyte coincides with that of the solvent in which the ions are dispersed. Only in the case where the ions are considered polarizable particles, their presence can contribute to the effective dielectric constant of the electrolyte and can play a role in the non-linear version of the Poisson-Nernst-Planck model. From this observation, it follows that generalizations of the linear Poisson-Nernst-Planck model in which the dielectric constant of the solution is considered depending on the ionic distributions are questionable.

Barbero, G.; Lelidis, I.

2014-05-01

322

Air-Stable, High-Conduction Solid Electrolytes of Arsenic-Substituted Li4SnS4  

Energy Technology Data Exchange (ETDEWEB)

Lithium-ion-conducting solid electrolytes show promise for enabling high-energy secondary battery chemistries and solving safety issues associated with conventional lithium batteries. Achieving the combination of high ionic conductivity and outstanding chemical stability in solid electrolytes is a grand challenge for the synthesis of solid electrolytes. Herein we report the design of aliovalent substitution of Li4SnS4 to achieve high conduction and excellent air stability based on the hard and soft acids and bases theory. The composition of Li3.833Sn0.833As 0.166S4 has a high ionic conductivity of 1.39 mS/cm 1 at 25 C. Considering the high Li+ transference number, this phase conducts Li+ as well as carbonate-based liquid electrolytes. This research also addresses the compatibility of the sulfide-based solid electrolytes through chemical passivation.

Sahu, Gayatri [ORNL; Lin, Zhan [ORNL; Li, Juchuan [ORNL; Liu, Zengcai [ORNL; Dudney, Nancy J [ORNL; Liang, Chengdu [ORNL

2014-01-01

323

Electrolyte changes in stroke.  

Science.gov (United States)

The present study was carried out in the department of Neurology and Medicine, Mymensingh Medical College Hospital, Bangladesh during the period of January 2009 to December 2010 to see the electrolyte changes in stroke. The serum concentration of Na?, K?, and Cl? were measured in 110 cases during acute period of stroke (55 ischemic and 55 haemorrhagic strokes). Data were analyzed by computer with SPSS programme using 't' test and chi square test. In haemorrhagic stroke, out of 55 patients 29(52.72%) had abnormal sodium level, of them 23(41.8%) had hyponatremia, 6(10.9%) had hypernatremia. In contrast in ischemic stroke 23(41.80%) out of 55 had abnormal sodium level, of them 21(38%) had hyponatremia. The result showed that hyponatremia is almost equally common in both haemorrhagic and ischaemic group without significant difference (p>0.05). The study also revealed that hyponatremia is more common than hypernatremia in both groups. Mean ± SD of age of the haemorrhagic group was 60.80 ± 15.97 while the age of ischaemic group was 59.89 ± 15.84 years. Male, female ratio in haemorrhagic and ischaemic group 1:0.62 and 1:0.89 respectively. Mean ± SD of serum Na?, K?, Cl? in haemorrhagic group were 136.18 ± 10.5, 3.83 ± 0.65, 97.96 ± 16.74 mmol/L, in ischaemic group 135.08 ± 9.08, 4.00 ± 0.75, 100.27 ± 8.39 mmol/L. The result showed no significant difference in haemorrhagic and ischemic stroke. Hyponatremia, hypokalamia and hyperchloredemia were more common than hypernatremia, hyperkalamia and hyperchloredemia. In haemorrhagic stroke, out of 55 patients, 21(38.18%) had abnormal potassium level, of them 19(34.55%) had hypokalemia, 2(3.63%) had hyperkalemia. In contrasts, in ischemic stroke, 15 out of 55(27.22%) had abnormal potassium level. Of them 12(21.81%) had hypokalemia and 3(5.45%) had hyperkalemia. The finding showed that hypokalemia is almost equally common in both haemorrhagic and ischaemic group without significant difference. The study also revealed that hypokalemia is more common than hyperkalemia in both groups. In haemorrhagic stroke, out of 55 patients 33(60%) had abnormal chloride level. Of them 20(36.4%) had hypochrloridemia, 13(23%) had hyperchrloridemia, in contrast, in ischemic stroke, 40 out of 55(60%) had abnormal chloride level, of them 22(40%) had hypochrloridemia and 18(32.7%) had hyperchrloridemia. The result showed that changes in chloride level after haemorrhagic and ischemic stroke are similar. The result showed hypochrloridemia is more common than hyperchrloridemia in both groups. PMID:23134903

Alam, M N; Uddin, M J; Rahman, K M; Ahmed, S; Akhter, M; Nahar, N; Swapan, M K; Alam, M M; Sultana, N; Hallaz, M M; Alam, M M; Uddin, M M; Bari, M S; Israil, M A

2012-10-01

324

Development of magneto-rheological fluid composites with rigidification characteristics  

Science.gov (United States)

Magnetic and magneto-rheological materials have been widely used in many engineering applications. The smart magnetic materials addressed in this study consist of magnetically activated composites made from a core layer of a carrier-material-like fabric, sponge and silicone in combination with small magnetizable ferrous particles suspended in a magneto-rheological fluid. Composite materials that contain magnetic and magneto-rheological ingredients are presently becoming very popular in shape and structure control solutions in a variety of engineering applications. The magneto-rheological response in smart materials allows for the real-time adaptation of material properties. Adequately designed magneto-rheological or magnetic composites are required to perform under different load conditions and provide some rigidification in a sample or a structure. Three different composites are developed in this study including: magneto-rheological fabric composites (MR/FC), magnetic elastomers (M-elastomers) and magneto-rheological sponge composites (MR/SC). The experimental set-up, including custom-made hardware, software and data acquisition system, is designed to conduct experiments used to quantify the material response in shear, tension and compression. The experimental results show a close correlation between the amount of magneto-rheological material present in the specimen and the final displacements in the samples. The resistance to the shear, compressive or tensile forces increases in the samples with the higher concentration of ferrous particles when subjected to a magnetic field. An increased intensity of the magnetic field allows for a stronger magneto-rheological effect and more stable formation of the ferrous chains inside the composites.

Glaser, Radek; Caccese, Vincent; Shahinpoor, Mohsen

2011-04-01

325

Experimental Investigation of Orthoenstatite Single Crystal Rheology  

Science.gov (United States)

The plasticity of enstatite, upper mantle second most abundant mineral, is still poorly constrained, mostly because of its high-temperature (T) transformation into proto- and clino-enstatite at low pressure (P). Mackwell (1991, GRL, 18, 2027) reports a pioneer study of protoenstatite (Pbcn) single-crystal rheology, but the results do not directly apply to the orthorhombic (Pbca) mantle phase. Ohuchi et al. (2011, Contri. Mineral. Petrol , 161, 961) carried out deformation experiments at P=1.3 GPa on oriented orthoenstatite crystals, investigating the activity of [001](100) and [001](010) dislocation slip systems; they report the first rheological laws for orthoenstatite crystals. However, strain and stress were indirectly constrained in their experiments, which questioned whether steady state conditions of deformation were achieved. Also, data reported for [001](100) slip system were obtained after specimens had transformed by twinning into clinoenstatite. We report here new data from deformation experiments carried out at high T and P ranging from 3.5 to 6.2 GPa on natural Fe-bearing enstatite single crystals, using the Deformation-DIA apparatus (D-DIA) that equipped the X17B2 beamline of the NSLS (NY, USA). The applied stress and specimen strain rates were measured in situ by X-ray diffraction and imaging techniques (e.g., Raterron & Merkel, 2009, J. Sync. Rad., 16, 748; Raterron et al., 2013, Rev. Sci. Instr., 84, 043906). Three specimen orientations were tested: i) with the compression direction along [101]c crystallographic direction, which forms a 45° angle with both [100] and [001] axes, to investigate [001](100) slip-system activity; ii) along [011]c direction to investigate [001](010) system activity; iii) and along enstatite [125] axis, to activate both slip systems together. Crystals were deformed two by two, to compare slip system activities, or against enstatite aggregates or orientated olivine crystals of known rheology for comparison. Run products microstructures were investigated by transmission electron microscopy. Despite a significant hardening with P, enstatite [001](100) slip system is found to be the easiest system at mantle P and T. Furthermore, orthoenstatite crystals exhibit a higher sensitivity to stress than olivine crystals, i.e. a higher n exponent in classical power laws. At the low stress level prevailing in the Earth mantle, enstatite crystals are thus harder than olivine crystals.

fraysse, G.; Girard, J.; Holyoke, C. W.; Raterron, P.

2013-12-01

326

Rheology of Dense Granular Mixtures and Slurries  

Science.gov (United States)

Dense granular flows, characterized by multiple contacts between grains, are common in many industrial processes and natural events, such as debris flows. Understanding the characteristics of these flows is crucial to predict quantities such as bedrock erosion and distance traveled by debris flows. However, the rheological properties of these flows are complicated due to wide particle size distribution and presence of interstitial fluids. Models for dense sheared granular materials indicate that their rheological properties depend on particle size, but the representative particle size for mixtures is not obvious. Using the discrete element method (DEM) we study sheared granular binary mixtures in a Couette cell to determine the relationship and rheological parameters such as stress and effective coefficient of friction and particle size distribution. The results indicate that the stress does not depend monotonically on the average particle size as it does in models derived from simple dimensional consideration. The stress has an additional dependence on a measure of the effective free volume per particle that is adapted from an expression for packing of monosized particles near the jammed state. The effective friction also has a complicated dependence on particle size distribution. For these systems of relatively hard particles, these relationships are governed largely by the ratio between average collision times and mean-free-path times. The characteristics of shallow free surface flows, important for applications such as debris flows, are different from confined systems. To address this, we also study shallow granular flows in a rotating drum. The stress at the boundary, height profiles and segregation patterns from DEM simulations are quantitatively similar to the results obtained from physical experiments of shallow granular flows in rotating drums. Individual particle-bed impacts rather than enduring contacts dominate the largest forces on the drum bed, which vary as the grain size squared and the 1.2 power of particle-bed impact velocity. In the presence of interstitial fluids (water + fine particles) these characteristics might change significantly. Modeling particle-particle and fluid-particle interaction in dense granular flows is still a challenge. We propose a modification to the DEM to account for specific effects of the interstitial fluid on the dynamics of certain granular fluid flows. The results from this simple model are qualitatively similar to results from experiments.

Tewoldebrhan, Bereket Yohannes

327

Rheological properties of cupuassu and cocoa fats  

Directory of Open Access Journals (Sweden)

Full Text Available Cocoa butter is an important ingredient in chocolate formulation as it dictates the main properties (texture, sensation in the mouth, and gloss. In the food industry, the texture of fat-containing products strongly depends on the macroscopic properties of the fat network formed within the finished product. Cupuassu ( Theobroma grandiflorum , Sterculiaceae is an Amazonian native fruit and the seeds can be used to derive a cocoa butter like product. In general, these fats are similar to those of cocoa, although they are different in some physical properties. The objective of this study was to analyze several properties of the cupuassu fat and cocoa butter (crystal formation at 25 ° C, rheological properties, and fatty acid composition and mixtures between the two fats (rheological properties, in order to understand the behavior of these fats for their use in chocolate products. Fat flow was described using common rheological models ( Newton , Power Law, Casson and Bingham plastic.La manteca de cacao es un ingrediente muy importante en la formulación de chocolates y es responsable de la mayor parte de sus propiedades (textura, palatibilidad y brillo. En la industria de alimentos, la textura de productos que contienen grasa depende enormemente de las propiedades macroscópicas de la red cristalina de la grasa en el producto final. El cupuaçu es una fruta nativa de la región amazónica y sus semillas pueden ser usadas para obtener una grasa semejante a la manteca de cacao. En general, esta grasa es similar a la manteca de cacao, pero difiere en algunas de sus propiedades fisicas . El objetivo de este estudio fue analizar algunas propiedades de la grasa de cupuaçu y de la manteca de cacao (formación de cristales a 25 °C, propiedades reológicas y composición en ácidos grasos y de algunas mezclas entre las dos grasas (propiedades reológicas, a fin de conocer el comportamiento de estas grasas para ser usadas en productos de la industria del chocolate. El flujo de la grasa se ha descrito utilizando modelos reológicos comunes (Newton, ley de la potencia, Casson y plástico de Bingham.

Gioielli, L. A.

2004-06-01

328

Rheology and interfacial tension of biopolymers  

Science.gov (United States)

The rheology and interfacial tension of biomaterials are important factors governing their potential use in biomedical applications. This dissertation presents a study of the rheology and interfacial tension of three very different biomaterials: (1) A hydrophobically modified Hyaluronic acid (HA) with polypeptide side chains, (2) Actin fibers and (3) a highly hydrophobic fluoroalkane, Perfluoropentane, and the effect of various surfactants and their mixtures on lowering its interfacial tension in an aqueous interface. In Chapter 1, we present a description of the properties and applications of these materials and a detailed literature review relevant to our studies to better understand the motivation of our work. In Chapter 2 we describe the techniques used for our studies. In Chapter 3, we present our studies on the hydrophobically modified HA with polyleucine side chains and compare them to unmodified HA of same or similar backbone molecular weights. We found a significantly enhanced viscosity for the modified HA compared to unmodified HA at the same concentration. We also found a viscoelastic behavior that was dependent on the concentration of the solution and grafting ratio of the hydrophobic side chains. The associative thickening properties of modified HA investigated with various rheological experiments and simulation results are presented in this chapter. In Chapter 4, we present our studies on the properties of actin fibers. We used a novel microrheometer VROC(TM) (Viscometer-rheometer-on-a-chip) for studying actin fibers at very high shear rates. We show that at very high shear rats, the actin filaments show irreversible network breakdown. We also studied the surface tension of actin filaments and monomer solutions at the interface with air and report induction times of these materials. In Chapter 5, we study the interfacial tension of a highly hydrophobic fluoroalkane, Perfluoropentane, in the presence of different surfactants and their mixtures. The surfactants studied are commonly used amphiphilic biopolymers polyethylene oxide-co-polylactic acid (PEO-PLA) and polyethylene oxide-co-poly-epsilon-caprolactone (PEO-PCL), and cetyl trimethyl ammonium bromide (CTAB). A significant lowering of the interfacial tension was observed with all these surfactants with the greatest lowering in the presence of CTAB.

Kandadai, Madhuvanthi A.

329

Shear History Extensional Rheology Experiment II (SHERE II) Microgravity Rheology with Non-Newtonian Polymeric Fluids  

Science.gov (United States)

The primary objective of SHERE II is to study the effect of torsional preshear on the subsequent extensional behavior of filled viscoelastic suspensions. Microgravity environment eliminates gravitational sagging that makes Earth-based experiments of extensional rheology challenging. Experiments may serve as an idealized model system to study the properties of lunar regolith-polymeric binder based construction materials. Filled polymeric suspensions are ubiquitous in foods, cosmetics, detergents, biomedical materials, etc.

Jaishankar, Aditya; Haward, Simon; Hall, Nancy Rabel; Magee, Kevin; McKinley, Gareth

2012-01-01

330

Polymer Electrolytes for Lithium/Sulfur Batteries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S) batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.

The Nam Long Doan; Denise Gosselink; Yongguang Zhang; Mikhail Sadhu; Ho-Jae Cheang; Pu Chen; Yan Zhao

2012-01-01

331

Polymer Electrolytes for Lithium/Sulfur Batteries  

Directory of Open Access Journals (Sweden)

Full Text Available This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.

The Nam Long Doan

2012-08-01

332

LOWER TEMPERATURE ELECTROLYTE AND ELECTRODE MATERIALS  

Energy Technology Data Exchange (ETDEWEB)

A thorough literature survey on low-temperature electrolyte and electrode materials for SOFC is given in this report. Thermodynamic stability of selected electrolyte and its chemical compatibility with cathode substrate were evaluated. Preliminary electrochemical characterizations were conducted on symmetrical cells consisting of the selected electrolyte and various electrode materials. Feasibility of plasma spraying new electrolyte material thin-film on cathode substrate was explored.

Keqin Huang

2003-04-30

333

Electrolytic beryllium deposit on liquid zinc cathode  

International Nuclear Information System (INIS)

Influence of electrolyte composition, cathode of current density, temperature and mixing on fractional of beryllium deposit, selected on the liquid zinc cathode at an electrolysis of a chlorine-fluoride electrolyte was investigated. Fine powders of electrorefining beryllium using electrolyte containing equimolar mixture out of potassium and sodium chlorides with 15% beryllium fluoride under intensive mixing of zinc cathode and electrolyte under cathode current density up to 1 A/cm2 have been obtained

334

Novel poly(ethylene glycol) gel electrolytes prepared using self-assembled 1,3:2,4-dibenzylidene-D-sorbitol.  

Science.gov (United States)

Gel electrolytes have usually been prepared by adding gelators or polymers to the liquid organic solvent-based electrolytes. In this study, we proposed a method to prepare gel electrolytes using gelators in liquid (low molecular weight) polymer-based electrolytes. Inexpensive 1,3:2,4-dibenzylidene-D-sorbitol (DBS) was chosen as a gelator for poly(ethylene glycol) (PEG)-based electrolytes at relatively low DBS concentrations. A series of gel electrolytes was produced by varying the DBS amounts, PEG molecular weights and PEG end groups. First, we found that DBS molecules self-assembled into 3-D networks consisting of nanofibrils that were approximately 10 nm in diameter, as measured by transmission electron microscopy; they exhibited spherulite-like morphologies under polarizing optical microscopy. Second, the dynamic rheological measurements demonstrated that the elastic modulus and the dissolution temperature of DBS-PEG gels increased with the increasing DBS content. The thermal degradation temperature of these gels also increased when the DBS concentration increased, as determined by thermogravimetric analysis. In addition, adding DBS may help to facilitate the dissolution of iodide and iodine in PEG due to its ether groups. Furthermore, the conductivity of the prepared DBS-PEG gel electrolytes was similar to that of the liquid PEG electrolytes (without DBS). When used in dye-sensitized solar cells (DSSC), the PEG-based electrolytes having inactive methyl end groups achieved the highest energy conversion efficiency among the tested cells. The efficiency of DSSC filled with our gel electrolytes remained basically the same over a one-month period, implying that the materials were relatively stable. PMID:24651903

Lai, Wei-Chi; Chen, Chien-Chu

2014-01-14

335

Improved stability of quasi-solid-state dye-sensitized solar cell based on poly (ethylene oxide)-poly (vinylidene fluoride) polymer-blend electrolytes  

Energy Technology Data Exchange (ETDEWEB)

We report two improved stability dye-sensitized TiO{sub 2} solar cells using poly (ethylene oxide)-poly (vinylidene fluoride) (PEO-PVDF) polymer-blend electrolytes modified with water and ethanol as hydroxyl-rich small-molecule additives. The effect of additive on the thermal property, viscosity, conductivity and the corresponding performance of the dye-sensitized solar cell (DSSC) were studied. After introducing the water and ethanol into the PEO-PVDF polymer-blend electrolytes, the conductivity is improved compared to that of the un-added electrolyte. This is due to the enhanced free ion concentration and ion transport channels in the electrolyte because of the cross-linking ability of these hydroxyl-rich additives. The increased ion concentration can be proved by the enhanced concentration of I{sup -} and I{sub 3}{sup -} in the additive-modified electrolytes from UV-vis studies. The increased cross-linking network can be explained by the increased glass transition temperature (T{sub g}) and viscosity of these additive-modified electrolytes from DSC and rheology studies. A more homogeneous morphology of ethanol-modified electrolyte from SEM study is used to further explain the better conductivity and stability of the cells based on these additive-modified electrolytes. From the evaluation of additive effect on the performance of the corresponding DSSC, we find that introducing water and ethanol leads to an increase in short-circuit photocurrent density (J{sub sc}). This is due to the efficient transport of I{sup -}/I{sup 3-} caused by enhanced I{sup -}/I{sup 3-} concentration and increased ion transport channels in the electrolyte by adding additives. The best efficiency of 3.9% is achieved in the cell with ethanol-modified electrolyte. (author)

Yang, Ying; Zhou, Cong-hua; Xu, Sheng; Hu, Hao; Chen, Bo-lei; Zhang, Jing; Wu, Su-juan; Liu, Wei [Department of Physics, Wuhan University, Wuhan 430072 (China); Zhao, Xing-zhong [Department of Physics, Wuhan University, Wuhan 430072 (China); Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072 (China)

2008-12-01

336

Numerical Implementation of Ice Rheology for Europa's Shell  

Science.gov (United States)

We present a discussion of approximations to the temperature dependent part of the rheology of ice. We have constructed deformation maps using the superplastic rheology of Goldsby & Kohlstedt and find that the rheologies that control convective flow in the Europa's are likely grain boundary sliding and basal slip for a range of grain sizes 0.1 mm Europa, implementing the non-Newtonian, lab-derived flow law directly is required to accurately judge the onset of convection in the ice shell and temperature gradient in the near-surface ice.

Barr, A. C.; Pappalardo, R. T.

2004-01-01

337

[Rheology and hyaluronic acid in inflammatory joint effusions (author's transl)].  

Science.gov (United States)

The Weissenberg rheogoniometer was used to measure viscosity, normal force and the number of molecular entanglements, calculated from a shear modulus obtained by prestationary experiments, in inflammatory and non-inflammatory synovial fluid effusions. The rheological properties show greater pathological change in the inflammatory synovial fluid samples than in the non-inflammatory. Variation in the hyaluronic acid concentration is only partly responsible for the pathological rheology. Initial experiments with a normalization method for the viscosity flow curves suggest the possibility of determining changes in polymerization or structure of the hyaluronic acid by rheological measurements. PMID:919558

Zeidler, H; Altmann, S

1977-11-11

338

Local interactions and global rheology in disordered media  

Science.gov (United States)

We generalize our scaling model for the rheology of soft, frictionless repulsive spheres to include general local viscous and elastic interactions and come to a prediction of the effect on the global behavior of these local interactions. As our scaling model combines elastic and geometric ingredients and a power balance that depends on the local viscous law, we predict that the global rheology of disordered media depends on the details of the local interactions in a universal but non-trivial manner. We compare our predictions for the effect of different elastic interactions to recent experimental results on the interactions and rheology of NIPA particles.

Woldhuis, Erik; Tighe, Brian; Nordstrom, Kerstin; Durian, Doug; Gollub, Jerry; van Hecke, Martin

2012-02-01

339

Rheological study of chitosan and its blends: An overview  

Directory of Open Access Journals (Sweden)

Full Text Available Chitosan, a modified natural carbohydrate polymer derived from carapaces of crabs and shrimps, has received a great deal of attention for its applications in diverse fields owing to its biodegradability, biocompatibility, non-toxicity and anti-bacterial property. The wide-ranging applications involve a broad spectrum of characterisation techniques and rheology represents one technique of growing importance in this field. This paper is an attempt to review the latest development in the rheology of chitosan, either on its own or associated with other materials, including the parameters that strongly influence its rheological behaviour such as concentration, pH and temperature.

Esam A. El-hefian

2010-06-01

340

Solid lithium-ion electrolyte  

Science.gov (United States)

The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li.sub.2 O--CeO.sub.2 --SiO.sub.2 system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications.

Zhang, Ji-Guang (Golden, CO); Benson, David K. (Golden, CO); Tracy, C. Edwin (Golden, CO)

1998-01-01

 
 
 
 
341

Solid lithium-ion electrolyte  

Science.gov (United States)

The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li{sub 2}O--CeO{sub 2}--SiO{sub 2} system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications. 12 figs.

Zhang, J.G.; Benson, D.K.; Tracy, C.E.

1998-02-10

342

Zinc electrode in alkaline electrolyte  

Energy Technology Data Exchange (ETDEWEB)

The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

McBreen, J.

1995-12-31

343

Thermodynamics and rheology of cycloolefin copolymers  

Science.gov (United States)

Cycloolefin copolymers of ethylene and norbornene, with norbornene content in the range from 36to62mol%, were studied with respect to the thermal, thermodynamic, and rheological properties using differential scanning calorimetry, pressure-volume-temperature, and dynamic mechanical measurements. All copolymers obey the principle of time-temperature superposition, i.e., they can be considered as thermorheologically simple except for a temperature range in the vicinity of Tg. Despite this, the results on (i) the ratio of activation energies EV*/H* used to quantify the origin of the liquid-to-glass transition, (ii) the pressure coefficient of the glass temperature Tg(P), and (iii) the dynamic fragility m suggest increasing dynamic heterogeneity with increasing norbornene content that is driven by the structural heterogeneity along the backbone.

Blochowiak, M.; Pakula, T.; Butt, H.-J.; Bruch, M.; Floudas, G.

2006-04-01

344

Transient rheology of crystallizing andesitic magmas  

Science.gov (United States)

The viscosity of magma strongly influences its rheological behaviour, which is a key determinant of magma transport processes and volcanic eruptions. Understanding the factors controlling the viscosity of magma is important to our assessment of hazards posed by active volcanoes. In nature, magmas span a very wide range in viscosity (10-1 to 1014 Pa s), depending on chemical composition (including volatile content), temperature, and importantly, crystal fraction, which further induces a complex strain rate dependence (i.e. non-Newtonian rheology). Here, we present results of transient viscosities of a crystallizing andesitic melt (57 wt.% SiO2) from Tungurahua volcano (Ecuador). We followed the experimental method developed by Vona et al. (2011) for the concentric cylinder apparatus, but optimized its implementation by leaving the spindle in situ before quenching the experimental products, to preserve the complete developed texture of the sample. The viscosity is investigated under super-liquidus (1400 ° C) and sub-liquidus temperatures (1162 and 1167 ° C). For each temperature increment, thermal equilibrium is achieved over a period of days while the spindle constantly stirs the magma. Simultaneous monitoring of the torque is used to calculate the apparent viscosity of the transient suspension. To get a better understanding of the nucleation and crystal growth processes that are involved at sub-liquidus conditions, further time-step experiments were carried out, where the samples were quenched at various equilibration stages. The mineralogical assemblage, as well as the crystal fraction, distribution and preferential alignment were then quantitatively analyzed. At temperatures below the liquidus, the suspension shows a progressive, but irregular increase of the relative shear viscosity. First, the viscosity slightly increases, possibly due to the crystallization of small, equant oxides and the formation of plagioclase nuclei. After some time (1.5-2.5 days), crystallization of large, tabular plagioclase begins, inducing a significantly stronger increase in apparent viscosity until thermo-chemical equilibration is achieved. After continued stirring the apparent viscosity slightly decreases, likely due to increasing crystal alignment. The analysis of pre-equilibrium quenched samples indicates that crystals nucleate and grow preferentially in proximity to both the spindle and the crucible wall. Furthermore, decreasing the stirring rate (aka strain rate) results in an increase in the apparent viscosity, which evidences the non-Newtonian characteristics of the magmatic suspension. In conclusion, these experiments indicate that natural andesitic magmas undergo significant rheological changes at the onset of crystallization. The observed thermo-chemical variations elucidate a transient viscosity, which deserves consideration into all problems of magma transport. Reference: Vona, A., Romano, C., Dingwell, D.B., Giordano, D. 2011. The rheology of crystal-bearing basaltic magmas from Stromboli and Etna. Geochim. Cosmochim. Acta, 75, 3214-3236.

de Biasi, L. J.; Chevrel, M. O.; Hanson, J. B.; Cimarelli, C.; Lavallée, Y.; Dingwell, D. B.

2012-04-01

345

Microfluidic Rheology of Soft Colloids near Jamming  

Science.gov (United States)

The rheology near jamming of a suspension of soft colloidal spheres is studied using pressure-driven flow in a deep 25 ?m wide microchannel. The system is composed of N-isopropylacrylamide (NIPA) microgel particles which exhibit thermoresponsive behavior; the suspension packing fraction is modified with a slight change in temperature. We use a force balance argument to infer the shear stress in the channel and use particle image velocimetry (PIV) to measure the strain rate. Stress vs. strain rate curves show clear non-Newtonian behavior below the jamming point and yield stress behavior above the jamming point. The data may be collapsed onto two branches but with different critical exponents than those obtained by Olsson and Teitel [1]. These results give credence to the idea that jamming is similar to a phase transition, but with interaction-dependent critical exponents. [1] Olsson and Teitel, PRL 2007

Nordstrom, Kerstin; Verneuil, E.; Arratia, P. E.; Gollub, J. P.; Durian, D. J.

2010-03-01

346

The Rheological Property of Potato Starch Adhesives  

Directory of Open Access Journals (Sweden)

Full Text Available The main goal of this study was to use potato starch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly potato starch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of potato starch adhesives decreased with the increasing of temperature; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared within potato starch adhesives which was pseudo-plastic fluids. Potato starch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

Junjun Liu

2014-02-01

347

Rheology of irradiated honey from Parana region  

International Nuclear Information System (INIS)

Viscosity characteristics can be governed by the molecular chain length of sugars present in the honey. Honey is essentially a mixture of sugar and water. When a physical treatment, as gamma radiation, is applied to food, some changes on its viscosity may occur. Viscosity is one of the important properties of honey and depends on water and sugar quantities. The objective of this work was to verify the rheological behavior of irradiated honey from Parana region in comparison to the unirradiated one. Each rheogram was measured at different shear rates that was increased to a certain value then immediately decreased to the starting point ('up and down curves'). These measurements were made for control and irradiated samples (5 and 10 kGy) in different temperatures (30 deg. C, 35 deg. C and 40 deg. C). The curves constructed with shear stress against shear rate presented linearity. Honey, irradiated and control, showed a Newtonian behavior and gamma radiation did not affect it

348

Erythrocyte dynamics in flow affects blood rheology  

International Nuclear Information System (INIS)

Normal blood consists of highly deformable particles (red blood cells, RBC, or erythrocytes) suspended in a Newtonian fluid (blood plasma). As a rough physical model of erythrocytes, giant unilamellar vesicles (GUV) are successfully used to probe their membrane properties. In shear flows vesicles and red blood cells show rich variety of dynamical behaviours influencing the rheological properties of their suspensions. Here, we focus on new experimental aspects of the problem in the case, when a combination of an oscillatory shear rate and a basic constant shear rate is applied to suspensions. Experimental examples with concentrated RBC suspensions are presented together with a discussion on the importance of the superposition of a constant shear flow to the pure oscillation, which is usually used to extract the viscoelastic properties of a complex fluid.

349

Impact of Helicobacter Pylori on Mucus Rheology  

Science.gov (United States)

It is well known that the viscoelastic properties of gastric mucin are crucial to the protection of the lining of the stomach against its own acidic secretions and other agents. Helicobacter Pylori, a rod shaped, gram-negative bacteria that dwells in the mucus layer of approximately 50% of the world's population is a class I carcinogen and is associated with gastric ulcers and severe gastritis. The structural damage to the mucus layer caused by H. Pylori is an important aspect of infection with this bacteria. We are examining the impact of H. Pylori on mucin and mucus rheology quantitatively using a combination of dynamic light scattering and multiple particle tracking experiments. Video microscopy data will also be presented on the motility of this bacteria in mucin at different pH and in other viscoelastic gels.

Celli, Jonathan; Keates, Sarah; Kelly, Ciaran; Turner, Bradley; Bansil, Rama; Erramilli, Shyamsunder

2006-03-01

350

Erythrocyte dynamics in flow affects blood rheology  

Science.gov (United States)

Normal blood consists of highly deformable particles (red blood cells, RBC, or erythrocytes) suspended in a Newtonian fluid (blood plasma). As a rough physical model of erythrocytes, giant unilamellar vesicles (GUV) are successfully used to probe their membrane properties. In shear flows vesicles and red blood cells show rich variety of dynamical behaviours influencing the rheological properties of their suspensions. Here, we focus on new experimental aspects of the problem in the case, when a combination of an oscillatory shear rate and a basic constant shear rate is applied to suspensions. Experimental examples with concentrated RBC suspensions are presented together with a discussion on the importance of the superposition of a constant shear flow to the pure oscillation, which is usually used to extract the viscoelastic properties of a complex fluid.

Vitkova, V.; Farutin, A.; Polack, B.; Misbah, C.; Podgorski, T.

2012-12-01

351

Rheological properties of sodium smectite clay  

International Nuclear Information System (INIS)

The rheological properties of Na-smectite Mx-80 have been investigated by various laboratory tests. The investigations include determination of the hydraulic conductivity, the undrained stress-strain-strength properties, the creep properties, the compression and swelling properties in drained and undrained conditions and the undrained thermomechanical properties. Measurements have been made at different densities, clay/sand mixtures and pore water compositions. The influence of temperature, rate of strain and testing technique has also been considered. The investigation has led to a supply of basic data for the material models which will be used at performance calculations. The results have also increased the general understanding of the function of smectitic clay as buffer material. The microstructural behaviour has been considered at the validation of the different test results and the validity of the effective stress theory has been discussed. Comparisons with the properties of Ca-smectite have also been made. (orig.)

352

Rheological Characterization of Vegetal Pear (Sechium edule)  

Science.gov (United States)

The national production of Mexican vegetal pear (Sechium edule) is located at the present time in more than 130,000 ton/year. The vegetal pear that produced in the center zone of the state of Veracruz is known in international markets; however it is a product that practically has not been studied. This work identifies the rheological behavior of vegetal pear (Sechium edule). A rheometer MCR301 of Anton Paar was utilized for viscosity and shear stress measurements. The objective of this experimental was modeling the rheological behavior of vegetal pear suspensions at three concentrations (1, 2 and 3% w/w), three particle size (1.00, 1.19 and 1.40 mm), at the same conditions of temperature (25, 40 and 70 °C). The results showed that all the suspensions there was a phenomenological behavior as a dilatants fluid (n>1) the performance of flow was represented by the Herschel-Bulkley model, and present values of "yield stress" between from 0.1 to 15 Pa for the different experiments. During evaluation of the activation energy of the suspensions of vegetal pear was found that decreases from 154.4039 kJ/mol to 9.1086 kJ/mol for a particle size of 1.00 mm to 1.4 mm, which implies that the effect of temperature is higher with smaller grains, in this case 1.00 mm. Furthermore, we assessed the effect of particle size by the Péclet number, showing an increase of the viscosity when the Péclet number also increases.

Castillo-Reyes, José A.; Luna-Solano, Guadalupe; Cantú-Lozano, Denis

2008-07-01

353

[Effect of smoking on blood rheology].  

Science.gov (United States)

The aim of this study was to compare the effects of cigarette smoking on biologic and rheologic tests, chiefly on the red blood cells (RBC) in measuring the deformability by the Cell Transit Analyser (CTA) and their aggregation by using an ultrasonic interferometry method based on A-mode echography allowed for the measurement of the accumulation rate of particles in a solid plate which is related to their sedimentation rate (Echo-Cell). Nine male smoker subjects with a high nicotine addiction measured by Fagerström questionnaire (> 8) and level of carbon monoxide (CM) in the breathed out air (> 20 ppm), have been compared with ten healthy no-smoker volunteers (CM < 3 ppm). One smoker has been eliminated of statistic evaluations because his glucose level showed a diabetes (10.5 mmol/l). A nailfold capillaroscopy performed in all subjects has eliminated the patterns of latent vasculitis or scleroderma. RBC and platelets counts, hemoglobin, ionogram, gamma GT, ASAT, ALAT, uric acid, total cholesterol and glucose levels were not significantly different between the two groups. On the other hand, in the smoker group, white blood cells count, serum triglycerides and especially fibrinogen values were higher than in the non-smoker's group. RBC sedimentation rate was normal in the two groups but was higher in smoker's group too. Without consumption of alcohol, the mean RBC volume was more important in smokers (91.9 +/- 1.2 versus 87.5 +/- 0.4, p = 0.003). Rheologic tests were more pathologic in smokers. The transit time or RBC by CTA was longer than in control group (1.6 ms +/- 0.02 versus 1.2 +/- 0.05, p = 0.0003). Echo-Cell technic showed a number and size of RBC aggregates more important with a rate of speed of accumulation higher than in the control group. These results demonstrated the toxic effects of smoking alone on blood toward a propensity for thrombotic status. PMID:9411009

Maurel, A; Apovo, M; Beuzard, Y; Boynard, M; Lagrue, G

1997-10-01

354

Rheological characterization of Alaska heavy oils  

Science.gov (United States)

Heavy crude oil reserves from the North Slope of Alaska are highly viscous, biodegraded oils that make standard oil production methods ineffective. A matrix of 18 mixtures with varying sand and water contents encompass the properties likely to be seen during production, especially cold production methods. Physical properties of the Alaska heavy oils were studied by viscosity measurements, including small amplitude shear tests and flow tests in a temperature range of -10°C to 60°C. The viscosity was observed to decrease with increasing temperature and displayed shear thinning. The activation energy of viscosity as a function of temperature ranged between 67 kJ/mol and 92 kJ/mol, similar to other heavy oils. Sand content alters the viscosity by up to 370% and non-monotonically while the water content changes viscosity by 53% or less. Also, a high pressure rheology apparatus was constructed to measure viscosity of Alaska heavy oil saturated with methane at pressures from 15 psi to 1800 psi and shear rates from 0.1 s-1 to 500 s-1. Viscosity of Alaska heavy oil is pressure dependent showing an order of magnitude decrease at a pressure of 1500 psi. Viscosity had a minimum value of 0.11 Pa-s and a maximum value of 590 Pa-s at 60°C/1810 psi and 0°C/15 psi, respectively. These rheological properties contribute to the overall objective of the project which is to advance seismic monitoring, using chemical and physical characterization of core samples in combination with stimulated production experiments, to optimize the recovery of heavy oils from Alaskan deposits.

Akeredolu, Babajide

355

Electrolyte measurement device and measurement procedure  

Science.gov (United States)

A method and apparatus for measuring the through-thickness resistance or conductance of a thin electrolyte is provided. The method and apparatus includes positioning a first source electrode on a first side of an electrolyte to be tested, positioning a second source electrode on a second side of the electrolyte, positioning a first sense electrode on the second side of the electrolyte, and positioning a second sense electrode on the first side of the electrolyte. current is then passed between the first and second source electrodes and the voltage between the first and second sense electrodes is measured.

Cooper, Kevin R. (Southern Pines, NC); Scribner, Louie L. (Southern Pines, NC)

2010-01-26

356

Polymeric electrolytes for ambient temperature lithium batteries  

Energy Technology Data Exchange (ETDEWEB)

A new type of highly conductive Li{sup +} polymer electrolyte, referred to as the Innovision polymer electrolyte, is completely amorphous at room temperature and has an ionic conductivity in the range of 10{sup {minus}3} S/cm. This report discusses the electrochemical characteristics (lithium oxidation and reduction), conductivity, and physical properties of Innovision electrolytes containing various dissolved salts. These electrolytes are particularly interesting since they appear to have some of the highest room-temperature lithium ion conductivities yet observed among polymer electrolytes. 13 refs. 11 figs., 2 tabs.

Farrington, G.C. (Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Materials Science and Engineering)

1991-07-01

357

Rheological behavior of Phanerochaete chrysosporium broth during lignin degradation.  

Science.gov (United States)

Rheological behavior of a lignin-degrading culture of Phanerochaete chrysosporium CDBB-H-298 was determined. Rheological characteristics revealed a Newtonian behavior in the culture medium without fungi, and a non-Newtonian dilatant behavior with fungi. In addition, the rheological behavior of the lignin-containing culture medium was complex, and changed from dilatant to pseudoplastic. During fungal growth without lignin in Kirk media rheological behavior exhibited a parabolic profile, and thixotropy showed a tendency to increase. Results indicated a small increase in the apparent viscosity in the presence of lignin; however, this may not affect the oxygen and mass transfer coefficients. The present findings can be applied to bioreactor desing for waste water treatment. PMID:11759909

Hernández-Peñaranda, A M; Salazar-Montoya, J A; Rodriguez-Vázquez, R; Ramos-Ramirez, E G

2001-01-01

358

RHEOLOGY AND SCALING BEHAVIOR OF SWELLING CLAY DISPERSIONS  

Directory of Open Access Journals (Sweden)

Full Text Available The microstructure and scaling of rheological properties of colloidal gels of bentonite investigated as a function of volume fraction and strength of interparticle interaction over a range of volume fractions, elastic modulus is well described with a scaling law functions of volume fractions, while the role of interparticle attractions can be accounted for by expressing these rheological properties as (?/?g-1n, where ?g captures the strength of particle interaction and n the microstructure.The scaling variable (?p/?pc-1, suggested in percolation theory to describe rheological behavior near percolation transition, acts to collapse G’ data suggesting that along lines of constant (?/?g-1 these gels are rheologically identical.

S. CHAOUI

2012-12-01

359

Rheology and contact lifetimes in dense granular flows.  

Science.gov (United States)

We study the rheology and distribution of interparticle contact lifetimes for gravity-driven, dense granular flows of noncohesive particles down an inclined plane using large-scale, three dimensional, granular dynamics simulations. Rather than observing a large number of long-lived contacts as might be expected for dense flows, brief binary collisions predominate. In the hard-particle limit, the rheology conforms to Bagnold scaling, where the shear stress is quadratic in the strain rate. As the particles are made softer, however, we find significant deviations from Bagnold rheology; the material flows more like a viscous fluid. We attribute this change in the collective rheology of the material to subtle changes in the contact lifetime distribution involving the increasing lifetime and number of the long-lived contacts in the softer particle systems. PMID:17930867

Silbert, Leonardo E; Grest, Gary S; Brewster, Robert; Levine, Alex J

2007-08-10

360

Bentonites from Boa Vista, Brazil: physical, mineralogical and rheological properties  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this work is to characterize physically and mineralogically six samples of natural and industrialized bentonites from Paraíba, Brazil, and to study its rheological properties to be used as a components of water based drilling fluids. Also it is intended to compare the evolution of the mineralogical composition and rheology of these clays after 40 years of exploitation. The natural bentonite clays were transformed into sodium bentonite by addition of concentrated Na2CO3 solution. The suspensions were prepared with 4.86% w/w to measure their rheological properties (apparent and plastic viscosities and water loss. The results showed that: i the samples present typical mineralogical compositions of bentonites, but after four decades of exploitation, presents inferior quality and ii among the clays samples, only one presented satisfactory rheological properties be used as a components of water based drilling fluids.

Luciana Viana Amorim

2004-12-01

 
 
 
 
361

Bentonites from Boa Vista, Brazil: physical, mineralogical and rheological properties  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The aim of this work is to characterize physically and mineralogically six samples of natural and industrialized bentonites from Paraíba, Brazil, and to study its rheological properties to be used as a components of water based drilling fluids. Also it is intended to compare the evolution of the min [...] eralogical composition and rheology of these clays after 40 years of exploitation. The natural bentonite clays were transformed into sodium bentonite by addition of concentrated Na2CO3 solution. The suspensions were prepared with 4.86% w/w to measure their rheological properties (apparent and plastic viscosities and water loss). The results showed that: i) the samples present typical mineralogical compositions of bentonites, but after four decades of exploitation, presents inferior quality and ii) among the clays samples, only one presented satisfactory rheological properties be used as a components of water based drilling fluids.

Luciana Viana, Amorim; Cynthia Morais, Gomes; Helio de Lucena, Lira; Kepler Borges, França; Heber Carlos, Ferreira.

2004-12-01

362

Microwave heating effect on rheology and microstructure of white sauces.  

Science.gov (United States)

The microstructure and rheological properties of white sauces formulated with different starches were analyzed after being microwave-heated for different times. Significant differences (P rheological parameters analyzed-storage modulus (G'), loss modulus (G?), and loss tangent (tan?)-were obtained for sauces made with different starches. Microwave reheating did not affect G' and G? values until water evaporation became significant. In addition, tan? values did not change significantly (P rheological measurements since starch and ?-carrageenan are mainly responsible for the viscoelastic behavior of the sauces. Practical Application:? The development of products appropriate to microwave heating is constantly rising in food industry. It is necessary to understand the behavior of the ingredients and the final product to microwave heating in order to choose those ingredients which will develop the best performance. Starches are common ingredients in industrial sauces, and rheological and microstructural techniques have shown their usefulness in characterization of starch-based systems. PMID:21913921

Guardeño, Luis M; Sanz, Teresa; Fiszman, Susana M; Quiles, Amparo; Hernando, Isabel

2011-10-01

363

Rheological Properties of HyperMacs—Long Chain Branched Analogues of Hyperbranched Polymers  

Science.gov (United States)

HyperMacs are long chain branched analogues of hyperbranched polymers, differing only in the sense that they have polymer chains, rather than monomers between branch points. Although the building blocks for HyperMacs, AB2 macromonomers, can be well-defined in terms of molecular weight and polydispersity, the nature of the coupling strategy adopted for the synthesis of the HyperMacs results in branched polymers with a distribution of molecular weights and architectures. Melt rheology showed polystyrene HyperMacs to be thermorheologically simple, obeying William-Landel-Ferry (WLF) behavior. Zero shear viscosities of the polymers were shown to increase with average molecular weight and the melts display shear thinning behavior. HyperMacs showed little evidence for relaxation by reptation and the rheological behavior agreed well with the Cayley tree model for hierarchical relaxation in tube models of branched polymers. This implies that HyperMacs exhibit architectures similar in nature to long chain branched polymers obtained commercially from metallocene catalysts.

Dodds, Jonathan M.; De Luca, Edoardo; Hutchings, Lian R.; Clarke, Nigel

2008-07-01

364

Dispersions of silica nanoparticles in ionic liquids investigated with advanced rheology  

International Nuclear Information System (INIS)

The colloidal stabilities of dispersions of unmodified and surface-functionalized SiO2 nanoparticles in hydrophobic and hydrophilic imidazolium-based ionic liquids were studied with advanced rheology at three temperatures (25, 100, and 200 °C). The rheological behavior of the dispersions was strongly affected by the ionic liquids hydrophilicity, by the nanoparticles surface, by the concentration of the nanoparticles in the dispersion as well as by the temperature. The unmodified hydrophilic nanoparticles showed a better compatibility with the hydrophilic ionic liquid. The SiO2 surface functionalization with hydrophobic groups clearly improved the colloidal stability of the dispersions in the hydrophobic ionic liquid. The temperature increase was found to lead to a destabilization in all studied systems, especially at higher concentrations. The results of this study imply that ionic liquids with tailored properties could be used in absorbers directly after reactors for gas-phase synthesis of nanoparticles or/and as solvents for their further surface functionalization without agglomeration or aggregation.

365

Dispersions of silica nanoparticles in ionic liquids investigated with advanced rheology  

Energy Technology Data Exchange (ETDEWEB)

The colloidal stabilities of dispersions of unmodified and surface-functionalized SiO{sub 2} nanoparticles in hydrophobic and hydrophilic imidazolium-based ionic liquids were studied with advanced rheology at three temperatures (25, 100, and 200 Degree-Sign C). The rheological behavior of the dispersions was strongly affected by the ionic liquids hydrophilicity, by the nanoparticles surface, by the concentration of the nanoparticles in the dispersion as well as by the temperature. The unmodified hydrophilic nanoparticles showed a better compatibility with the hydrophilic ionic liquid. The SiO{sub 2} surface functionalization with hydrophobic groups clearly improved the colloidal stability of the dispersions in the hydrophobic ionic liquid. The temperature increase was found to lead to a destabilization in all studied systems, especially at higher concentrations. The results of this study imply that ionic liquids with tailored properties could be used in absorbers directly after reactors for gas-phase synthesis of nanoparticles or/and as solvents for their further surface functionalization without agglomeration or aggregation.

Wittmar, Alexandra; Ruiz-Abad, David; Ulbricht, Mathias, E-mail: mathias.ulbricht@uni-due.de [Lehrstuhl fuer Technische Chemie II, Universitaet Duisburg-Essen (Germany)

2012-02-15

366

Local Rheology of Human Neutrophils Investigated Using Atomic Force Microscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the immune response, neutrophils display localized mechanical events by interacting with their environment through the micro-vascular transit, trans-endothelial, and trans-epithelial migration. Nano-mechanical studies of human neutrophils on localized nano-domains could provide the essential information for understanding their immune responsive functions. Using the Atomic Force Microscopy (AFM) - based micro-rheology, we have investigated rheological properties of the adherent human...

Yong J Lee, Dipika Patel

2011-01-01

367

Washing liquid effect on surimi gel rheological properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this research was to compare the rheological properties of the modori and su-wari gels, obtained from minced carp washed with water and electro-activated by water systems. The results of comparative analysis of rheological properties of suwari and modori gels from minced carp, washed with tap water, catholyte and anolyte are presented. Effective viscosity in all cases is reversibly reduced with increasing shear rate and is stabilized for all considered soft gel samples at strai...

Vinnov Alexey Sergeevich; Maevskaya Tatyana Nickolayevna; Dolganova Natalia Vadimovna

2013-01-01

368

Rheological and Electrical Transitions in Carbon Nanotube/Epoxy Suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rheological and electrical properties of suspensions of carbon nanotubes in an uncured epoxy resin were investigated by means of shear rheology and impedance spectroscopy. It was found that above an onset CNT weight fraction (0.1 wt %), the steady viscosity increased with CNT loading and presented a shear thinning behaviour. The concentration dependence of viscosity changed from a power law to an exponential with increasing shear rate, indicating a loss of interaction between aggregates a...

Allaoui, Aissa; El Bounia, Nour-eddine

2010-01-01

369

Rheology and texture of doughs: applications on wheat and corn  

Directory of Open Access Journals (Sweden)

Full Text Available A dough made of maylacceou materials shows a viscoelastic behavior, its macroestructural behavior depends on processing conditions, its constitutents and the interaction among them. Studies on dough rheology and texture are useful and important for applications that include ingredient specifications, quality control, product design and adaptation of new processing technologies. This work is a review of rheological and textural principles, testing methods and characteristics of wheat and com doughs.

Eduardo Rodríguez Sandoval

2010-04-01

370

Scaling of plate-tectonic convection with pseudoplastic rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The scaling of plate-tectonic convection is investigated by simulating thermal convection with pseudoplastic rheology and strongly temperature-dependent viscosity. The effect of mantle melting is also explored with additional depth-dependent viscosity. Heat-flow scaling can be constructed with only two parameters, the internal Rayleigh number and the lithospheric viscosity contrast, the latter of which is determined entirely by rheological properties. The critical viscosity ...

Korenaga, Jun

2010-01-01

371

Rheology of Carbon Fibre Reinforced Cement-Based Mortar  

International Nuclear Information System (INIS)

Carbon fibre reinforced cement based materials (CFRCs) offer the possibility of fabricating 'smart' electrically conductive materials. Rheology of the fresh mix is crucial to satisfactory moulding and fresh CFRC conforms to the Bingham model with slight structural breakdown. Both yield stress and plastic viscosity increase with increasing fibre length and volume concentration. Using a modified Viskomat NT, the concentration dependence of CFRC rheology up to 1.5% fibre volume is reported

372

Relationship between dynamic recrystallization, grain size distribution and rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The solid state flow behavior (rheology) of materials constituting the Earth?s mantle and crust is of key importance in controlling the dynamics of large scale geodynamic processes, such as mantle convection, subduction, mountain building and basin formation. Flow laws that are calibrated using laboratory experiments can provide constraints on the rheology of rock materials under natural conditions, given that all active deformation mechanisms and microphysical processes ...

Heege, Johannes Hendrik Ter

2002-01-01

373

Electrolytic decontamination method for radioactive contamination materials  

International Nuclear Information System (INIS)

Purpose: To improve the working efficiency and decrease the radiation exposure to workers by enabling continuous procession for electrolytic processing system. Method: Materials to be processed such as radioactive equipments or the likes are immersed as an anode in an electrolytic cell containing liquid electrolytes comprising electrolytes such as phosphoric acid and oxalic acid and incorporated with non-radioactive ions of the same kind as that of radioactive metal ions to be decontaminated. Then, radioactive metal ions are leached out into the electrolytic cell. The leached ions are electrolytically deposited to the depositing cathode disposed in the electrolytic cell to decontaminate the radioactive metals from the materials to be processed. Further, by replacing the depositing cathodes, radioactive metal ions can be processed continuously to improve the workability for the procession. (Moriyama, K.)

374

Characteristics analysis of electrolytic tritium separation using solid polymer electrolyte  

International Nuclear Information System (INIS)

The characteristics of electrolytic tritium separation using solid polymer electrode were analyzed. H-T separation factor (SFHT) and D-T separation factor (SFDT) were calculated from equilibrium constant of the hydrogen isotope exchange reaction between water and diatomic hydride and from two-phase distribution theory for isotopes. The calculated SFHT and SFDT were well agreed with the experimental values. The theory used in this study will available to select optimum cathode materials. (author)

375

Nonlocal granular rheology: Role of pressure and anisotropy  

Science.gov (United States)

We probe the secondary rheology of granular media, by imposing a main flow and immersing a vane-shaped probe into the slowly flowing granulate. The secondary rheology is then the relation between the exerted torque T and rotation rate ? of our probe. In the absence of any main flow, the probe experiences a clear yield-stress, whereas for any finite flow rate, the yield stress disappears and the secondary rheology takes on the form of a double-exponential relation between ? and T. This secondary rheology does not only depend on the magnitude of T, but it is also anisotropic —which we show by varying the relative orientation of the probe and main flow. By studying the depth dependence of the three characteristic torques that characterize the secondary rheology, we show that for counterflow, the dominant contribution is frictional-like —i.e., T and pressure are proportional for given ?— whereas for coflow, the situation is more complex. Our experiments thus reveal the crucial role of anisotropy for the rheology of granular media.

Wandersman, Elie; van Hecke, Martin

2014-01-01

376

Granular nanocrystalline zirconia electrolyte layers deposited on porous SOFC cathode substrates  

International Nuclear Information System (INIS)

Thin granular yttria-stabilized zirconia (YSZ) electrolyte layers were prepared by chemical vapor synthesis and deposition (CVD/CVS) on a porous substoichiometric lanthanum-strontium-manganite (ULSM) solid oxide fuel cell cathode substrate. The substrate porosity was optimized with a screen printed fine porous buffer layer. Structural analysis by scanning electron microscopy showed a homogeneous, granular nanocrystalline layer with a microstructure that was controlled via reactor settings. The CVD/CVS gas-phase process enabled the deposition of crack-free granular YSZ films on porous ULSM substrates. The electrolyte layers characterized with impedance spectroscopy exhibited enhanced grain boundary conductivity.

377

Review Of Rheology Models For Hanford Waste Blending  

International Nuclear Information System (INIS)

The area of rheological property prediction was identified as a technology need in the Hanford Tank Waste - waste feed acceptance initiative area during a series of technical meetings among the national laboratories, Department of Energy-Office of River Protection, and Hanford site contractors. Meacham et al. delivered a technical report in June 2012, RPP-RPT-51652 ''One System Evaluation of Waste Transferred to the Waste Treatment Plant'' that included estimating of single shell tank waste Bingham plastic rheological model constants along with a discussion of the issues inherent in predicting the rheological properties of blended wastes. This report was selected as the basis for moving forward during the technical meetings. The report does not provide an equation for predicting rheological properties of blended waste slurries. The attached technical report gives an independent review of the provided Hanford rheological data, Hanford rheological models for single tank wastes, and Hanford rheology after blending provided in the Meacham report. The attached report also compares Hanford to SRS waste rheology and discusses some SRS rheological model equations for single tank wastes, as well as discussing SRS experience with the blending of waste sludges with aqueous material, other waste sludges, and frit slurries. Some observations of note: Savannah River Site (SRS) waste samples from slurried tanks typically have yield stress >1 Pa at 10 wt.% undissolved solids (UDS), while core samples largely have little or no yield stress at 10 wt.% UDS. This could be due to how the waste has been processed, stored, retrieved, and sampled or simply in the differences in the speciation of the wastes. The equations described in Meacham's report are not recommended for extrapolation to wt.% UDS beyond the available data for several reasons; weak technical basis, insufficient data, and large data scatter. When limited data are available, for example two to three points, the equations are not necessarily satisfactory (justified) for interpolations, due to the number of unknown variables equal the number of known data points, resulting in a coefficient of determination of one. SRS has had some success predicting the rheology of waste blends for similar waste types using rheological properties of the individual wastes and empirical blending viscosity equations. Both the Kendall-Monroe and Olney-Carlson equations were used. High accuracy was not obtained, but predictions were reasonable compared to measured flow curves. Blending SRS processed waste with frit slurry (much larger particles and the source of SRS glass formers) is a different sort of problem than that of two similar slurries of precipitated waste particles. A different approach to rheology prediction has had some success describing the incorporation of large frit particles into waste than the one used for blending two wastes. In this case, the Guth-Simha equation was used. If Hanford waste is found to have significant particles in the >100 ?m diameter range, then it might be necessary to handle those particles differently from broadly distributed waste particles that are primarily <30 ?m in diameter. The following are recommendations for the Hanford tank farms: Investigate the impact of large-scale mixing operations on yield stress for one or more Hanford tanks to see if Hanford waste rheological properties change to become more like SRS waste during both tank retrieval and tank qualification operations; Determine rheological properties of mobilized waste slurries by direct measurement rather than by prediction; Collect and characterize samples during the waste feed qualification process for each campaign; From single source tanks that feed the qualification tanks; Blends from the qualification tanks; Predictive rheological models must be used with caution, due to the lack of data to support such models and the utilization of the results that come from these models in making process decisions (e.g. the lack of actual operation experience). As experience is gained, the use of blen

378

THERMOPHYSICAL AND RHEOLOGIC PROPERTIES OF BIOOIL SAMPLES  

Directory of Open Access Journals (Sweden)

Full Text Available This article deals with thermal properties of selected biooils Plahyd S biooil No1 and Plahyd N biooil No2 and rheologic properties of rapeseed oil. Plahyd S is a synthetic, rapidly biodegradable fluid which is based on sustainable raw materials. It is exceptionally suitable for applications in mobile and stationary hydraulic systems. Plahyd N is multigrade hydraulic oil based on rapeseed oil used in agricultural and construction machinery. For thermal parameters measurements was used Hot wire method. The experiment is based on measuring of the temperature rise vs. time evaluation of an electrically heated wire embedded in the tested material. The thermal conductivity is derived from the resulting change in temperature over a known time interval. Dependency of material resistance against the probe rotation was used at measurement of rheologic properties with instrument viscometer Anton Paar DV 3P. For two samples of biooils Plahyd N and Plahyd S were determined basic thermophysical parameters thermal conductivity, thermal diffusivity and volume specific heat. For each biooil samples were made two series of measurements. In the first series were measured thermal conductivity and thermal diffusivity at constant room temperature 20 C. Every thermophysical parameter was measured 10 times for each sample. The results were statistically processed. For biooil No1 thermal conductivity was 0.325 W*m 1 .K1 , it was higher value than we obtained for biooil No2 0.224 W*m 1 .K 1 . The similar results were obtained for thermal diffusivity of biooil No1 2.140.10 7 m 2 *s 1 and biooil No2 2.604.10 7 m 2* s 1 . For samples with constant temperature were calculated basic statistical characteristics as standard deviation for biooil No1 0.056 W*m 1*K 1 and biooil No2 0.054 W*m 1*K 1; probable error of the arithmetic average for biooil No 1 0.012 W*m 1*K 1 and biooil No 2 0.005 W*m 1*K 1, relative probable error in for biooil No1 3.69 per cent and biooil No2 2.23. The same statistical characteristics were calculated for thermal diffusivity. In the second series of measurements were measured relations of thermal conductivity and thermal diffusivity to the temperature in temperature range 20 29 C. From results was evident that all measured dependencies are nonlinear. For both thermophysical parameters were obtained polynomial functions of the second degree described by the polynomial coefficients. Type of function was selected according to statistical evaluation based on the coefficient of determination for every thermophysical parameter graphical dependency. In temperature dependency of rapeseed oil dynamic viscosity was used decreasing exponential function, which is in accordance with Arrhenius equation. The results obtained by the implementation of thermophysical and rheologic measurements on samples of biooils could be compared with the values presented in the literature.

Monika Bozikova

2013-09-01

379

Cerium ion conducting solid electrolyte  

Science.gov (United States)

A cerium ion conducting solid electrolyte, (Ce xZr 1- x) 4/4- xNb(PO 4) 3, was successfully realized with the NASICON-type structure which possesses a three-dimensional network, especially suitable for bulky ion migration. The cerium ion conductivity exceeds approximately one order of magnitude in comparison to that of the rare-earth ion conducting R2(WO 4) 3 and R1/3Zr 2(PO 4) 3 ( R=Sc, Y, Eu-Lu) series and the value is in the range between typical oxide anion conductors of yttria stabilized zirconia (YSZ) and calcia stabilized zirconia (CSZ). Since cerium ion has been demonstrated to be another migrating ion species in solid electrolyte field, a promising application for various functional materials is greatly expected.

Hasegawa, Yasunori; Imanaka, Nobuhito; Adachi, Gin-ya

2003-02-01

380

Improved Electrolytic Hydrogen Peroxide Generator  

Science.gov (United States)

An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

James, Patrick I.

2005-01-01

 
 
 
 
381

Composite electrode/electrolyte structure  

Science.gov (United States)

Provided is an electrode fabricated from highly electronically conductive materials such as metals, metal alloys, or electronically conductive ceramics. The electronic conductivity of the electrode substrate is maximized. Onto this electrode in the green state, a green ionic (e.g., electrolyte) film is deposited and the assembly is co-fired at a temperature suitable to fully densify the film while the substrate retains porosity. Subsequently, a catalytic material is added to the electrode structure by infiltration of a metal salt and subsequent low temperature firing. The invention allows for an electrode with high electronic conductivity and sufficient catalytic activity to achieve high power density in ionic (electrochemical) devices such as fuel cells and electrolytic gas separation systems.

Visco, Steven J. (Berkeley, CA); Jacobson, Craig P. (El Cerrito, CA); DeJonghe, Lutgard C. (Lafayette, CA)

2004-01-27

382

Electrical controlled rheology of a suspension of weakly conducting particles in dielectric liquid  

CERN Document Server

The properties of suspensions of fine particles in dielectric liquid (electrorheological fluids) subjected to an electric field lead to a drastic change of the apparent viscosity of the fluid. For high applied fields (~ 3-5 kV/mm) the suspension congeals to a solid gel (particles fibrillate span the electrode gap) having a finite yield stress. For moderate fields the viscosity of the suspension is continuously controlled by the electric field strength. We have roposed that in DC voltage the field distribution in the solid (particles) and liquid phases of the suspension and so the attractive induced forces between particles and the yield stress of the suspension are controlled by the conductivities of the both materials. In this paper we report investigation and results obtained with nanoelectrorheological suspensions: synthesis of coated nanoparticles (size ~ 50 to 600 nm, materials Gd2O3:Tb, SiOx...), preparation of ER fluids (nanoparticles mixed in silicone oil), electrical and rheological characterization ...

Guegan, Q; Foulc, J N; Tillement, O; Guegan, Quentin

2006-01-01

383

Suspension of SiC Powders in Allyhydridopolycarbosilane (AHPCS): Control of Rheology  

Science.gov (United States)

Inert particulate fillers can be blended with preceramic polymers prior to infiltration of composite preforms to increase pyrolysis yield and decrease shrinkage, thus reducing the number of infiltration/ pyrolysis cycles required for densification. However, particulate filler loadings and concentration of added dispersants necessary to maintain low viscosity (slurries vary with the characteristics of the particular AHPCS polymer batch. These batch to batch variations occur with alterations in the synthesis process and method of allyl substitution, which in turn alter polymer structure and molecular weight distribution. A number of different polymer batches were characterized by NMR, GPC and thermal analysis, and the influence of polymer structure on rheology of filled systems determined. When the high molecular weight fraction increased to too great a level, suitably fluid slurries could no longer be attained.

Hurwitz, Frances I.

1998-01-01

384

Cathode for an electrolytic capacitor  

International Nuclear Information System (INIS)

A metal container for use as a cathode in a tantalum electrolytic capacitor is drawn from a metal composite which has a layer of tantalum bonded to a copper layer in turn bonded to a nickel layer. The tantalum layer forms the interior of the can and the nickel, the exterior. A layer of tantalum carbide is formed on the tantalum interior ad is covered by a layer of finely-divided carbon

385

Plasma electrolytic oxidation of tantalum  

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This paper is a review of our research on the plasma electrolytic oxidation (PEO) process of tantalum in 12-tungstosilicic acid. For the characterization of microdischarges during PEO, real-time imaging and optical emission spectroscopy (OES) were used. The surface morphology, chemical and phase composition of oxide coatings were investigated by AFM, SEM-EDS and XRD. Oxide coating morphology is strongly dependent on PEO time. The elemental components of PEO coatings are Ta, O, Si and W....

Petkovi? Marija; Stojadinovi? Stevan; Vasili? Rastko; Bel?a Ivan; Kasalica Be?ko; Zekovi? Ljubiša

2012-01-01

386

Plasma electrolytic oxidation of metals  

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In this lecture results of the investigation of plasma electrolytic oxidation (PEO) process on some metals (aluminum, titanium, tantalum, magnesium, and zirconium) were presented. Whole process involves anodizing metals above the dielectric breakdown voltage where numerous micro-discharges are generated continuously over the coating surface. For the characterization of PEO process optical emission spectroscopy and real-time imaging were used. These investigations enabled the determinati...

Stojadinovi? Stevan

2013-01-01

387

Electrolytic precipitation of ammonium diuranate  

International Nuclear Information System (INIS)

Continuous precipitation of ammonium diuranate from a solution of uranyl sulphate and ammonium sulphate in the cathode compartment of an electrolytic cell has been investigated. It is found that the rate of precipitation and the settling rate of the precipitate can be correlated with the current consumed per unit volume of catholyte solution. The weight fraction of uranium in the dried solid product appears to be constant over the range of operating conditions used

388

Rheology and structure of thermoreversible hydrogels  

Science.gov (United States)

Highly concentrated solutions of non-ionic amphiphilic triblock copolymer poly(ethylene oxide)99-poly(propylene oxide)67-poly(ethylene oxide)99 (Pluronic F127) are widely used in numerous biomedical applications, such as drug delivery vehicles, and surfactants for emulsification of food and personal care products. The Pluronic copolymers are popular for these applications, since their gelation properties are thermoreversible and easily controlled by varying the concentration. They are liquid below room temperature and gel at body temperature. Hence they are great injectable biomaterials for tissue engineering and implantation. In this dissertation, thermal gelation and structure of high concentration triblock copolymer Pluronic F127-clay (Cloisite Na+ and Lucentite SWN) aqueous solutions were characterized by rheological measurements, differential scanning calorimetry (DSC) and small angle X-ray/neutron scattering. Small angle neutron scattering (SANS), under shear using a Couette cell in radial and tangential scattering geometry, was performed to examine the structural evolution of the polymeric micellar macro-lattice formed by concentrated aqueous solutions of triblock copolymer-Pluronic F127, as a function of the shear rate. The micellar gel showed a shear thinning, i.e., a reduction of the resistance to shear, by forming a layered stacking of two-dimensional hexagonally close packed (HCP) polymer micelles. A theoretical model was developed to calculate 2D SANS scattering patterns that can be compared with the experimental data. In order to improve the mechanical properties of the gel, while still maintaining the thermo-reversibility, we synthesized multiblock structures, where the F127 construct would be repeated several times. In this manner, physical interconnections between the micelles could occur as the multiblock copolymers formed interlocking loops and tails, thereby greatly increasing the mechanical strength of the gels. The rheological and structural properties of the gels were characterized as a function of temperature, composition and degree of polymerization. For F127 solutions just below their gel point, substitution of F127 with as little as 1% multiblock succeeded in forming a physical gel. Percolation theory was used to understand the modulus growth when multiblock was added to F127 solutions just below their gel point, assuming the multiblocks form bridges between adjacent micelles.

Jiang, Jun

389

Rheology and Gelling Behavior of Boehmite Sols  

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Full Text Available Rheological studies of boehmite sols based on pH was (1 to study the nature of flow properties of the boehmite sols and (2 to identify the sol-gel transition of boehmite sols with the change of pH of the liquid. It is evident that the shear rate and viscosity of the liquid exhibit a pseudoplastic (shear thinning flow behavior for all pH level. The transformation of sol-gel at low pH probably due to the hydrogen bond between the layers of the boehmite structure. The temperature has an appreciable effect on the activation energy during the sol-gel transition. The flow activation energies ?E? are in the range of 1.75 to 6.25 J mol-1 at temperature 298-384 K. Based on these results, the flow activation energy of boehmite sols sharply decreases with decreasing the pH. The flocculation of the suspension at pH 4 to 1 showed to be favourable in term of enhanced density of boehmite.

Eng-Seng Chan

2011-01-01

390

Rheological studies of polysaccharides for skin scaffolds.  

Science.gov (United States)

Polysaccharide hydrogels are good candidates for skin scaffolds because of their inherent biocompatibility and water transport properties. In the current study, hydrogels were made from a mixture of four polysaccharides: xanthan gum, konjac gum, iota-carrageenan, and kappa-carrageenan. Gel formation, strength, and structure of these polysaccharides were studied using rheological and thermal techniques. All gel samples studied were strong gels at all times because of the gradual water loss. However, after 12 h of storage, elastic (G') and loss (G'') moduli of hydrogel mixture containing all the ingredients is of one to two orders of magnitude greater than that of mixtures not containing either xanthan gum or iota-carrageenan, which confirmed the varied levels of gel strength. This is mainly due to the rate of water loss in each of these mixtures, resulting in gels of varying structures and dynamic moduli over a period of time. Iota-carrageenan and xanthan gum differ in their effect on gel strength and stability in combination with konjac gum and kappa-carrageenan. PMID:23703897

Almeida, Nalinda; Mueller, Anja; Hirschi, Stanley; Rakesh, Leela

2014-05-01

391

Rheological properties of cold recycled mixtures  

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Full Text Available The paper presents some of the results of research focused on cold recycled mixtures properties. Within the study, eight mixtures with a different amount of reclaimed asphalt, bitumen emulsion and cement were evaluated. The results of static creep, complex modulus and fatigue conducted on trapezoidal specimens are discussed in the paper. The static creep modulus and the complex modulus were investigated at temperatures 27 ºC, 11 ºC and 0 ºC. These temperatures represent temperatures of asphalt layer with a thickness in the range from 20 to 25 cm for summer, spring/ autumn and winter in Slovakia. In addition fatigue was investigated at the temperature of 27 ºC. It was found that the binder combination plays an important role in rheological performance of cold recycled mixtures. However, at different contents of reclaimed asphalt, the effect of bitumen emulsion was different. This can be observable particularly when analyzing the results of the fatigue test. The mixtures with a higher amount of cement were better in terms of the fatigue life. The investigated mixtures in general were little sensitive to the change of loading frequency which simulates the traffic speed.

Ján Gillinger

2007-04-01

392

Rheological properties of asphalts with particulate additives  

Energy Technology Data Exchange (ETDEWEB)

The Superpave asphalt binder specifications are performance-based specifications for purchasing asphalt binders for the construction of roads. This means that the asphalt is characterized by fundamental material (rheological) properties that relate to the distress modes of the pavements. The distress modes addressed are primarily rutting, fatigue cracking and low temperature cracking. For example, G*/sin({delta}) is designed to predict the rutting potential of pavements, where G* is the magnitude of the complex shear modulus and 6 is the phase angle. The binder for a road that is situated in a certain climatic zone requires the binder to have a minimum G*/sin({delta}) of 2200 Pa at the highest consecutive 7-day average pavement temperature the road had experienced. Implicit in such a performance based specification is that the fundamental property, G*/sin({delta}), of the binder correlates with rutting potential of the pavement