WorldWideScience
 
 
1

Composite polymer electrolytes using fumed silica fillers: synthesis, rheology and electrochemistry  

Energy Technology Data Exchange (ETDEWEB)

The goal of the synthesis research was to devise routes to PEG/fumed silica/lithium salt composites that can be processed and then photochemically cross-linked to form mechanically stable electrolytes. An essential feature of the system is that the ionic conductivity and the mechanical properties must be de-coupled from each other, i.e., cross-linking of the fumed silica matrix must not cause a significant deterioration of the conductivity of the composite. As shown in Figure 2, we prepared a range of surface-modified fumed silicas and investigated their ability to form mechanically stable composite electrolytes. The groups used to modify the surface properties of the silica ranged from simple linear alkyls that render the silica hydrophobia to polyethers that promote compatibility with the electrolyte. From these materials we developed a cross-linkable system that satisfies the criteria of processibility and high-conductivity. The key material needed for the cross-linking reaction are silicas that bear surface-attached monomers. As shown schematically in Figure 3a, we prepared fumed silicas with a combination of surface groups, for example, an octyl chain with different coverages of tethered methacrylates. The length of the tether was varied, and we found that both C{sub 3} and C{sub 8} tethers gave useful composites. The functionalized silicas were combined with PEG-DM, AIBN or benzophenone (free radical initiators), LiClO{sub 4} or Li imide, and either methyl, butyl, or octyl, methacrylate to form stable clear gels. Upon irradiation with UV light, polymerization of both the tethered methacrylate and the added methacrylate took place, yielding a cross-linked rubbery composite material. Ionic conductivity measurements before and after cross-linking showed only a slight decrease (see Figure 9 later), thereby offering strong experimental evidence that the mechanical properties conferred by the silica matrix are de-coupled from the ionic conductivity of the PEG-DM matrix.

Khan, Saad A.; Fedkiw, Peter S.; Baker, Gregory L.

1999-06-28

2

Self-Assembled Silica Nano-Composite Polymer Electrolytes: Synthesis, Rheology & Electrochemistry  

Energy Technology Data Exchange (ETDEWEB)

The ultimate objectives of this research are to understand the principles underpinning nano-composite polymer electrolytes (CPEs) and facilitate development of novel CPEs that are low-cost, have high conductivities, large Li+ transference numbers, improved electrolyte-electrode interfacial stability, yield long cycle life, exhibit mechanical stability and are easily processable. Our approach is to use nanoparticulate silica fillers to formulate novel composite electrolytes consisting of surface-modified fumed silica nano-particles in polyethylene oxides (PEO) in the presence of lithium salts. We intend to design single-ion conducting silica nanoparticles which provide CPEs with high Li+ transference numbers. We also will develop low-Mw (molecular weight), high-Mw and crosslinked PEO electrolytes with tunable properties in terms of conductivity, transference number, interfacial stability, processability and mechanical strength

Khan, Saad A.: Fedkiw Peter S.; Baker, Gregory L.

2007-01-24

3

Fumed silica-based composite polymer electrolytes: synthesis, rheology, and electrochemistry  

Science.gov (United States)

An overview of our research is presented on developing composite polymer electrolytes (CPEs) based on low-molecular weight polyethylene oxide (PEO) (namely, poly(ethylene glycol) dimethyl ether), lithium salts (e.g. lithium triflate, lithium imide, etc.), and fumed silica. These CPEs demonstrate high room-temperature conductivites (>10 -3 S/cm), mechanical strength, and form stable interfaces with lithium metal as a result of the fumed silica. The surface groups on the fumed silica determine the mechanical properties of the CPE while the low-molecular weight PEO and lithium salt determine the ionic transport properties. These CPEs show promise as electrolytes for the next generation of rechargeable lithium batteries.

Walls, H. J.; Zhou, Jian; Yerian, Jeffrey A.; Fedkiw, Peter S.; Khan, Saad A.; Stowe, Micah K.; Baker, Gregory L.

4

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

5

Electrolytic Synthesis and Characterizations of Silver Nanopowder  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work reports a simple, novel, cost effective and eco-friendly electrolytic synthesis of silver nanoparticles using AgNO3 as metal precursor. The synthesis rate is much faster than other methods and this approach is suitable for large scale production. They are characterized by XRD, SEM and FT-IR techniques to analyze size, morphology and functional groups. XRD studies reveal a high degree of crystallinity and monophasic Ag nanoparticles. Their particle size is found to ...

Theivasanthi, T.; Alagar, M.

2011-01-01

6

Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. ...

MichaelStoukides

2014-01-01

7

Xanthan Rheological: a review about the influence of electrolytes on the viscosity of aqueous solutions of xanthan gums  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several strains of Xanthomonas campestris are able to produce a bacterial biopolymer called xanthan which is widely used in the food industry. In order to have an effective use of the xanthan in the industry, not only the studies concerning the chemical properties of the xanthan should be considered, but also the studies related to its addition of electrolytes, and its effects in the rheological behaviour. When a new bacterial biopolymer is sinthetized, new rheological behaviours appear. This...

João Luiz Silva Vendruscolo; Patrícia Silva Diaz; Claire Tondo Vendruscolo

2004-01-01

8

Xanthan Rheological: a review about the influence of electrolytes on the viscosity of aqueous solutions of xanthan gums  

Directory of Open Access Journals (Sweden)

Full Text Available Several strains of Xanthomonas campestris are able to produce a bacterial biopolymer called xanthan which is widely used in the food industry. In order to have an effective use of the xanthan in the industry, not only the studies concerning the chemical properties of the xanthan should be considered, but also the studies related to its addition of electrolytes, and its effects in the rheological behaviour. When a new bacterial biopolymer is sinthetized, new rheological behaviours appear. This study aims at review the influence of the chemical structural and addition of salts to the rheological behaviour of the xanthan aqueous solution.

João Luiz Silva Vendruscolo

2004-01-01

9

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

10

Electrolytic Synthesis and Characterizations of Silver Nanopowder  

CERN Document Server

This work reports a simple, novel, cost effective and eco-friendly electrolytic synthesis of silver nanoparticles using AgNO3 as metal precursor. The synthesis rate is much faster than other methods and this approach is suitable for large scale production. They are characterized by XRD, SEM and FT-IR techniques to analyze size, morphology and functional groups. XRD studies reveal a high degree of crystallinity and monophasic Ag nanoparticles. Their particle size is found to be 24 nm and specific surface area (SSA) is 24 m2/g. Analysis of Ag nanoparticles SSA reports that increasing their SSA improves their antibacterial actions. Microbiology assay founds that Ag nanoparticles are effective against E.coli and B.megaterium bacteria. SSA of bacteria analysis reveals that it plays a major role while reacting with antimicrobial agents.

Theivasanthi, T

2011-01-01

11

Synthesis and characterizations of novel polymer electrolytes  

Science.gov (United States)

Polymer electrolytes are an important component of many electrochemical devices. The ability to control the structures, properties, and functions of polymer electrolytes remains a key subject for the development of next generation functional polymers. Taking advantage of synthetic strategies is a promising approach to achieve the desired chemical structures, morphologies, thermal, mechanical, and electrochemical properties. Therefore, the major goal of this thesis is to develop synthetic methods for of novel proton exchange membranes and ion conductive membranes. In Chapter 2, new classes of fluorinated polymer- polysilsesquioxane nanocomposites have been designed and synthesized. The synthetic method employed includes radical polymerization using the functional benzoyl peroxide initiator for the telechelic fluorinated polymers with perfluorosulfonic acids in the side chains and a subsequent in-situ sol-gel condensation of the prepared triethoxylsilane-terminated fluorinated polymers with alkoxide precursors. The properties of the composite membranes have been studied as a function of the content and structure of the fillers. The proton conductivity of the prepared membranes increases steadily with the addition of small amounts of the polysilsesquioxane fillers. In particular, the sulfopropylated polysilsesquioxane based nanocomposites display proton conductivities greater than Nafion. This is attributed to the presence of pendant sulfonic acids in the fillers, which increases ion-exchange capacity and offers continuous proton transport channels between the fillers and the polymer matrix. The methanol permeability of the prepared membranes has also been examined. Lower methanol permeability and higher electrochemical selectivity than those of Nafion have been demonstrated in the polysilsesquioxane based nanocomposites. In Chapter 3, the synthesis of a new class of ionic liquid-containing triblock copolymers with fluoropolymer mid-block and imidazolium methacrylate end-blocks is described for the first time. The synthetic strategy involves the preparation of the telechelic fluoropolymers using a functional benzoyl peroxide initiator as the macro-chain transfer agent for subsequent RAFT polymerization of the imidazolium methacrylate monomer. As revealed in DSC, SAXS and dielectric relaxation spectroscopy (DRS) measurements, there was no microphase separation in the triblock copolymers, likely due to solubility of ionic liquid moieties in the fluoropolymer matrix. The anionic counterion has direct impact on the thermal properties, ionic conductivity and segmental dynamics of the polymers. The temperature dependence of the ionic conductivity is well described by the Vogel-Tamman-Fulcher model, suggesting that ion motion is closely coupled to segmental motion. In Chapter 4 and 5, new solid electrolytes for lithium cations have been synthesized by catalyzed hydrosilylation reaction involving hydrogen atoms of polysiloxane and polyhedral oligomeric silsesquioxane (POSS) and double bonds of vinyl tris17-bromo-3,6,9,12,15- pentaoxaheptadecan-1-ol silane. The obtained structures are based on branched or dendritic with ionic liquid-ethylene oxide oligomer. High room temperature ionic conductivities have been obtained in the range of 10-4-10-5 can be regarded as solid electrolytes. This is attributed to the high concentration of ions from ionic liquid moieties in the tripodand molecule, high segmental mobility, and high ion dissociation from ethylene oxide spacers. The influence of anion structures and lithium salts and concentration has been investigated.

Chanthad, Chalathorn

12

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

13

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 cons...

Leonardo Tavares Stutz; Fernando Alves Rochinha

2011-01-01

14

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

15

Carboxymethylation of Cassia angustifolia seed gum: Synthesis and rheological study.  

Science.gov (United States)

The seeds of Cassia angustifolia are a rich source of galactomannan gum. The seed gums possess a wide variety of industrial applications. To utilize C. angustifolia seed gum for broader industrial applications, the carboxymethyl-Cassia angustifolia seed gum (CM-CAG) was synthesized. The gum was etherified with sodium monochloroacetate (SMCA) in a methanol-water system in presence of alkali (NaOH) at different reaction conditions. The variables studied includes alkali concentration, SMCA concentration, methanol:water ratio, liquor:gum ratio, reaction temperature and time. The extent of carboxymethylation was determined as degree of substitution (DS). The optimum conditions for preparing CM-CAG (DS=0.474) comprised 0.100mol of NaOH, 0.05mol of SMCA, 80% of methanol:water ratio (as % methanol) and liquor:gum ratio (v/w) of 10:1 at 75°C for 60min using 0.03mol (as AGU) of CAG. Rheological studies showed CM-CAG to exhibit non-Newtonian pseudoplastic behaviour, relatively high viscosity, cold water solubility and solution stability. PMID:25498663

Rajput, Gaurav; Pandey, I P; Joshi, Gyanesh

2015-03-01

16

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

17

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

18

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

19

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

20

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.

2011-12-01

 
 
 
 
21

Microplasma synthesis on aluminum with additions of iron and nickel soluble complexes in electrolyte  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Alkaline homogeneous electrolyte with transition metals complexes. Black-Right-Pointing-Pointer Coatings contain metallic iron, nickel and their oxides in alumina-silica matrix. Black-Right-Pointing-Pointer Effect of Fe/Ni ratio on coatings properties and process characteristics. - Abstract: The microplasma synthesis of coatings containing iron and nickel from homogeneous electrolytes has been studied. For stabilization of transition metals in solution, it is proposed to use chelation. It was found that the synthesis of coatings using alternating current leads to the formation of metallic iron and nickel particles in addition to oxide phases. The iron and nickel complexes concentrations ratio in the electrolyte correlates with the coatings composition. Obtained coatings have been studied by scanning electron microscopy with X-ray microanalyser and by X-ray diffraction with Cu and Mo radiation. The metal content in the coating was determined spectrophotometrically from the absorption of iron thiocyanate complexes and nickel dimethylglyoxime complex.

Rogov, A.B., E-mail: alex-lab@bk.ru [Nikolaev Institute of Inorganic Chemistry. 3, Acad. Lavrentiev Ave, Novosibirsk, 630090 (Russian Federation); Mironov, I.V.; Terleeva, O.P.; Slonova, A.I. [Nikolaev Institute of Inorganic Chemistry. 3, Acad. Lavrentiev Ave, Novosibirsk, 630090 (Russian Federation)

2012-10-01

22

Microplasma synthesis on aluminum with additions of iron and nickel soluble complexes in electrolyte  

International Nuclear Information System (INIS)

Highlights: ? Alkaline homogeneous electrolyte with transition metals complexes. ? Coatings contain metallic iron, nickel and their oxides in alumina–silica matrix. ? Effect of Fe/Ni ratio on coatings properties and process characteristics. - Abstract: The microplasma synthesis of coatings containing iron and nickel from homogeneous electrolytes has been studied. For stabilization of transition metals in solution, it is proposed to use chelation. It was found that the synthesis of coatings using alternating current leads to the formation of metallic iron and nickel particles in addition to oxide phases. The iron and nickel complexes concentrations ratio in the electrolyte correlates with the coatings composition. Obtained coatings have been studied by scanning electron microscopy with X-ray microanalyser and by X-ray diffraction with Cu and Mo radiation. The metal content in the coating was determined spectrophotometrically from the absorption of iron thiocyanate complexes and nickel dimethylglyoxime complex.

23

ASSOCIATIVE SYSTEMS BASED ON MODIFIED HYALURONIC ACID: SYNTHESIS AND STUDY OF THE RELATIONS BETWEEN THE STRUCTURE AND THE RHEOLOGICAL PROPERTIES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The work described in this memory is devoted to the development of new amphiphilic derivatives of hyaluronic acid (HA) obtained by grafting hydrophobic alkyl chains along the hydrophilic macromolecular backbone. The strategy of grafting presented was optimized in order to be able to transpose the synthesis on an industrial scale. The behavior in aqueous medium of the native polymers and the viscoelastic properties of the associative systems were studied by flow and dynamic rheological measure...

Kadi, Shirin

2007-01-01

24

Microplasma synthesis on aluminum with additions of iron and nickel soluble complexes in electrolyte  

Science.gov (United States)

The microplasma synthesis of coatings containing iron and nickel from homogeneous electrolytes has been studied. For stabilization of transition metals in solution, it is proposed to use chelation. It was found that the synthesis of coatings using alternating current leads to the formation of metallic iron and nickel particles in addition to oxide phases. The iron and nickel complexes concentrations ratio in the electrolyte correlates with the coatings composition. Obtained coatings have been studied by scanning electron microscopy with X-ray microanalyser and by X-ray diffraction with Cu and Mo radiation. The metal content in the coating was determined spectrophotometrically from the absorption of iron thiocyanate complexes and nickel dimethylglyoxime complex.

Rogov, A. B.; Mironov, I. V.; Terleeva, O. P.; Slonova, A. I.

2012-10-01

25

Solvothermal synthesis of gallium-indium-zinc-oxide nanoparticles for electrolyte-gated transistors.  

Science.gov (United States)

Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium-indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 10(6), threshold voltage (VTh) of 0.3-1.9 V, and mobility up to 1 cm(2)/(V s), as a function of gallium-indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping. PMID:25517251

Santos, Lídia; Nunes, Daniela; Calmeiro, Tomás; Branquinho, Rita; Salgueiro, Daniela; Barquinha, Pedro; Pereira, Luís; Martins, Rodrigo; Fortunato, Elvira

2015-01-14

26

Synthesis and Characterization of Thin Film Lithium-Ion Batteries Using Polymer Electrolytes  

Science.gov (United States)

The present paper describes the integration of thin film electrodes with polymer electrolytes to form a complete thin film lithium-ion battery. Thin film batteries of the type, LiCoO2 [PAN, EC, PC, LiN(CF3SO2)2] SnO2 have been fabricated. The results of the synthesis and characterization studies will be presented and discussed.

Maranchi, Jeffrey P.; Kumta, Prashant N.; Hepp, Aloysius F.; Raffaelle, Ryne P.

2002-01-01

27

Electrochemical synthesis of ammonia at atmospheric pressure and low temperature in a solid polymer electrolyte cell  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The heterogeneous electrocatalytic synthesis of ammonia rom nitrogen and water is carried out at Ru cathodes, using a Solid Polymer Electrolyte Cell (SPE), at atmospheric pressure and low temperature; the reduction rate increases with increase of temperature up to 100 °C, while with the increase of the negative potential a maximum is observed at 21.02 V vs. Ag/AgCl and gradually decreases in the hydrogen discharge region.

Kordali, V.; Kyriacou, G.; Lambrou, Ch

2012-01-01

28

Synthesis of tough nanoporous metals by controlled electrolytic dealloying  

Science.gov (United States)

Dealloying (selective dissolution) of homogeneous metallic alloys such as Ag-Au generates nanoporous metals with intriguing properties. Until now, it has not been possible routinely to prepare such materials in a form in which they would resist mechanical strains, such as might be encountered in applications as membranes, sensors or actuators. Now a threshold potential has been identified, for dealloying of Ag-Au in aqueous HClO4, above which spontaneous transgranular fracture occurs due to the formation of a monolayer of gold hydroxide. The fracture mechanism involves a reduction in surface diffusivity, preventing relaxation of induced tension in the porous material, and possible more exotic effects. By optimizing the Au content of the alloy, staying below the threshold potential and increasing the temperature of the electrolyte, dealloyed membranes with a high degree of mechanical integrity have been prepared. When prepared in this way, the nanoporous material shows peculiar behaviours, such as grain-boundary sintering under annealing, and reversible stiffening and embrittlement when dried in air.

Senior, N. A.; Newman, R. C.

2006-05-01

29

Synthesis and Rheological Characterization of Water-Soluble Glycidyltrimethylammonium-Chitosan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 constan...

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

2014-01-01

30

Associative polyelectrolytes: Synthesis, characterisation, rheology and application in Enhanced Oil Recovery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The studies presented in literature show that monografted Hydrophobically Modified Polymers (HMP) present in water original rheological properties. To improve the rheological properties of these systems, we played on the nature of grafting by particularly considering bigrafted HPE by mixing of short (C4) and long alkyl chains (C12). To clarify the respective effect of each graft on their associative properties, we decided to work on a model system where the degree of polymerization and distri...

Paillet, Sabrina

2009-01-01

31

Synthesis and investigation of electric conductivity of solid electrolytes in the LaF3-La2O3 system  

International Nuclear Information System (INIS)

Synthesis and investigation of electroconductivity of solid electrolytes in the system LaF3-La2O3 have been carried out. Electronic conductivity has been estimated. The conclusion about pure ionic character of electroconductivity in the investigated solid electrolytes LaF3-La2O3 has been made. The range existence and temperatures of polymorphous phase transition of LaOnF3-2n have been found. 11 refs., 2 figs., 1 tab

32

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

33

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

34

The preparation of some novel electrolytes: synthesis of partially fluorinated alkanesulfonic acids as potential fuel cell electrolytes. Final technical report  

Energy Technology Data Exchange (ETDEWEB)

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, H/sup 3/PO/sup 4/, currently under investigation by Fort Belvoir as a fuel cell electrolyte is TFMSA, CF/sup 3/SO/sup 3/H.H/sub 2/O, trifluoromethanesulfonic acid monohydrate aqueous solutions and sodium salt mixtures. TFMSA has been found to be superior to H/sup 3/PO/sup 4/ from the standpoint of electrode kinetics, but certain undesirable characteristics (volatility; wetting of Teflon) led to this research for a better fuel cell electrolyte.

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

1979-09-01

35

Towards the synthesis of hydroxyapatite/protein scaffolds with controlled porosities: bulk and interfacial shear rheology of a hydroxyapatite suspension with protein additives.  

Science.gov (United States)

The synthesis of porous hydroxyapatite scaffolds is essential for biomedical applications such as bone tissue engineering and replacement. One way to induce macroporosity, which is needed to support bone in-growth, is to use protein additives as foaming agents. Another reason to use protein additives is the potential to introduce a specific biofunctionality to the synthesized scaffolds. In this work, we study the rheological properties of a hydroxyapatite suspension system with additions of the proteins bovine serum albumin (BSA), lysozyme (LSZ) and fibrinogen (FIB). Both the rheology of the bulk phase as well as the interfacial shear rheology are studied. The bulk rheological data provides important information on the setting behavior of the thixotropic suspension, which we find to be faster with the addition of FIB and LSZ and much slower with BSA. Foam bubble stabilization mechanisms can be rationalized via interfacial shear rheology and we show that it depends on the growth of interfacial films at the suspension/air interface. These interfacial films support the stabilization of bubbles within the ceramic matrix and thereby introduce macropores. Due to the weak interaction of the protein molecules with the hydroxyapatite particles of the suspension, we find that BSA forms the most stable interfacial films, followed by FIB. LSZ strongly interacts with the hydroxyapatite particles and thus only forms thin films with very low elastic moduli. In summary, our study provides fundamental rheological insights which are essential for tailoring hydroxyapatite/protein suspensions in order to synthesize scaffolds with controlled porosities. PMID:23859812

Maas, Michael; Bodnar, Pedro Marcus; Hess, Ulrike; Treccani, Laura; Rezwan, Kurosch

2013-10-01

36

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

37

RHEOLOGICAL PHASE SYNTHESIS AND CHARACTERIZATION OF MICRO-SIZED Li4Ti5O12  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english 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 analy [...] sis (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; XIAOYU, CAO; CHANGWEI, LIU; CHIWEI, WANG.

38

Synthesis and rheological characterization of intercalated polystyrene /organophylic montmorillonite nano composite  

International Nuclear Information System (INIS)

Polystyrene ( PS) / organophilic montmorillonite ( OMMT) clay nano composites were prepared by intercalation method using a plastograph as a mixer. Intercalation of the OMMT in the PS matrix was achieved as revealed by X- ray diffraction. The IR spectra of the products indicated that the OMMT is homogeneously dispersed in the PS matrix. A thermogravimetric analysis ( TGA) showed that the maximum temperature of degradation increases with the clay content until 5%, then it decreases when it reaches 10%. The glass transition temperature of the PS, examined using differential scanning calorimetry, had a trend similar to that from the TGA. The rheological properties of the PS/ OMMT nano composites were also investigated via a rotational rheometer with a parallel plate geometry, The storage and loss moduli were increased with increasing the clay content. The stress at break is also improved relatively to the virgin polystyrene in our experimental conditions. Keywords: Montmorillonite, nano composite, melt intercalation, polystyrene, rheology thermal stability

39

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

40

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)

 
 
 
 
41

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.

42

Synthesis and Rheological Characterization of Water-Soluble Glycidyltrimethylammonium-Chitosan  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Syang-Peng Rwei

2014-11-01

43

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

2014-11-01

44

Use of Sodium Silicate from Rice Husk Ash Basic Materials for Coating Electrolytes in the Synthesis of Magnetite Nanoparticles22  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnetite nanoparticles had a measurement about 6,76 nm was synthesized through electrochemical technique in the synthetic sodium silicate solution which was gained through the extraction process of silica which content in the rice husk ash by using NaOH 1,5 M. Sodium silicate functions as electrolyte and simultaneously as a coated to maintain the size of the magnetite particle which was formed through electrolysis process. The synthesis of magnetite nanoparticles was implemented in the varia...

Syahrul, Muh

2013-01-01

45

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

Directory of Open Access Journals (Sweden)

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

46

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

47

Synthesis, extrusion and rheological behaviour of PU/HA composites for biomedical applications.  

Science.gov (United States)

Biostable polyurethane/hydroxyapatite (PU/HA) composites with potential application as bone replacement materials were synthesized in bulk and processed in a screw extruder. The polyurethanes (PU) were prepared by reacting an aliphatic diisocyanate, 4-methylene-bis-diisocyanate (MDI), with poly-(epsilon-caprolactone) (PCL) diols and polytetramethylene oxide (PTMO) of different molecular weights, extended with 1, 4-butanediol (BDO). Glass-transition temperatures were measured by differential scanning calorimetry (DSC). The specific PU groups were assessed by total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The effects of polymer chemistry and filler content on the rheological behaviour were studied by oscillatory rheometry. Polymers with larger chain lengths showed higher viscosity and, for identical chain lengths, polyether urethanes seem to have higher viscosities than polyester based urethanes. A lubricating effect was found for composites containing 50% weight of filler, whereas at higher filler contents a solid-like behaviour was measured. Polymer chemistry seems to be affected by ageing but not so by the presence of filler. Ageing is characterized by a decrease in the concentration of hydrogen bonds involving between urethane linkages. PMID:20405172

Machado, H B; Correia, Rui N; Covas, J A

2010-07-01

48

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

Directory of Open Access Journals (Sweden)

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

49

A synthesis of crystalline Li7P3S11 solid electrolyte from 1,2-dimethoxyethane solvent  

Science.gov (United States)

A crystalline solid electrolyte, Li7P3S11, was synthesized by a liquid-phase reaction of Li2S and P2S5 in an organic solvent. A precursor, which was a mixture of solvated Li3PS4 and Li4P2S7, was prepared by mixing Li2S and P2S5 powders in 1,2-dimethoxyethane (DME) solvent. After a vacuum drying of the precursor, the crystalline phase of Li7P3S11 was obtained by heat treatment at 250 °C for 1 h in Ar atmosphere. The Li7P3S11 sample showed high ionic conductivity of 2.7 × 10-4 S cm-1 at room temperature. The liquid-phase synthesis of the solid electrolyte has advantages for mass-production of all-solid-state batteries.

Ito, Seitaro; Nakakita, Moeka; Aihara, Yuichi; Uehara, Takahiro; Machida, Nobuya

2014-12-01

50

Synthesis and characterization of nanocrystalline dysprosia stabilized zirconia based electrolyte for intermediate-temperature solid oxide fuel cell  

Energy Technology Data Exchange (ETDEWEB)

The present work concerns studies on synthesis (by chemical co-precipitation) and characterization (microstructural and electrical) of 8 and 10 mol% dysprosia stabilized nanocrystalline cubic-zirconia (DySZ) for use as electrolyte materials in solid oxide fuel cell in the intermediate temperature range. Identity and crystallite size of the calcined powders were determined by X-ray diffraction. Microstructural studies of calcined/sintered product by transmission and scanning electron microscopes allowed verification of crystallite/particle size and analysis of morphology/density/distribution of the defects, respectively. Impedance spectroscopy revealed that the contribution of grain boundary resistance is higher than that of the bulk. Furthermore, conductivity analysis evidenced an Arrhenius type thermally activated ionic conduction above 300 deg. C. Thus, DySZ appears a possible alternative to yttria stabilized zirconia (YSZ) as electrolyte for solid oxide fuel cells due to its lower thermal and comparable ionic conductivity as YSZ.

Maiti, S.; Pastor, M.; Sundaram, R.S.; Ravichandran, J.; Kumar, A.; Biswas, K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, WB 721302 (India); Manna, I. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, WB 721302 (India)], E-mail: imanna@metal.iitkgp.ernet.in

2009-05-05

51

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

52

Synthesis and conductivity of PEGME branched poly(ethylene-alt-maleimide) based solid polymer electrolyte  

International Nuclear Information System (INIS)

A thermally stable comb-like polymer electrolyte, poly(ethylene glycol) monomethyl ether (PEGME) grafted poly(ethylene-alt-maleimide), has been synthesized and characterized. The copolymer was thermally stable up to 250.deg.C and had good film forming property. The copolymer was well mixed with poly(ethylene glycol) dimethyl ether(PEGDME, Mw = 400). The activation energy of ionic conduction decreased and conductivity increased with the increase of PEGDME content in the polymer electrolyte. The maximum conductivity of the resulting polymer electrolyte containing 66 wt% of PEGDME was found to be 3 x 10-4 S/cm at 30.deg.C. The polymer electrolyte showed electrochemical stability window of greater than 4.7 V

53

Synthesis and conductivity of PEGME branched poly(ethylene-alt-maleimide) based solid polymer electrolyte  

Energy Technology Data Exchange (ETDEWEB)

A thermally stable comb-like polymer electrolyte, poly(ethylene glycol) monomethyl ether (PEGME) grafted poly(ethylene-alt-maleimide), has been synthesized and characterized. The copolymer was thermally stable up to 250.deg.C and had good film forming property. The copolymer was well mixed with poly(ethylene glycol) dimethyl ether(PEGDME, M{sub w} = 400). The activation energy of ionic conduction decreased and conductivity increased with the increase of PEGDME content in the polymer electrolyte. The maximum conductivity of the resulting polymer electrolyte containing 66 wt% of PEGDME was found to be 3 x 10{sup -4} S/cm at 30.deg.C. The polymer electrolyte showed electrochemical stability window of greater than 4.7 V.

Kang, Yong Ku; Seo, Yeon Ho; Lee, Chang Jin [Korea Research Institute of Chemical Technology, Taejon (Korea, Republic of)

2000-02-01

54

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

55

Synthesis and electrochemical properties of lithium methacrylate-based self-doped gel polymer electrolytes  

International Nuclear Information System (INIS)

In this study, a strategy for synthesizing lithium methacrylate (LiMA)-based self-doped gel polymer electrolytes was described and the electrochemical properties were investigated by impedance spectroscopy and linear sweep voltammetry. LiMA was found to dissolve in ethylene carbonate (EC)/diethyl carbonate (DEC) (3/7, v/v) solvent after complexing with boron trifluoride (BF3). This was achieved by lowering the ionic interactions between the methacrylic anion and lithium cation. As a result, gel polymer electrolytes consisting of BF3-LiMA complexes and poly(ethylene glycol) diacrylate were successfully synthesized by radical polymerization in an EC/DEC liquid electrolyte. The FT-IR and AC impedance measurements revealed that the incorporation of BF3 into the gel polymer electrolytes increases the solubility of LiMA and the ionic conductivity by enhancing the ion disassociations. Despite the self-doped nature of the LiMA salt, an ionic conductivity value of 3.0 x 10-5 S cm-1 was achieved at 25 deg. C in the gel polymer electrolyte with 49 wt% of polymer content. Furthermore, linear sweep voltammetry measurements showed that the electrochemical stability of the gel polymer electrolyte was around 5.0 V at 25 deg. C.

56

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.

57

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

Energy Technology Data Exchange (ETDEWEB)

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.

Seo, Dong-Wan [Department of Applied Chemistry, Konkuk University, 322 Danwol-dong, 380-701 Chungju (Korea, Republic of); Sarker, Subrata; Nath, Narayan Chandra Deb [Department of Advanced Technology Fusion, Konkuk University, Seoul (Korea, Republic of); Choi, Seung-Woo [Department of Applied Chemistry, Konkuk University, 322 Danwol-dong, 380-701 Chungju (Korea, Republic of); Ahammad, A.J. Saleh [Department of Advanced Technology Fusion, Konkuk University, Seoul (Korea, Republic of); Lee, Jae-Joon, E-mail: jjlee@kku.ac.k [Department of Applied Chemistry, Konkuk University, 322 Danwol-dong, 380-701 Chungju (Korea, Republic of); Department of Advanced Technology Fusion, Konkuk University, Seoul (Korea, Republic of); Kim, Whan-Gi, E-mail: wgkim@kku.ac.k [Department of Applied Chemistry, Konkuk University, 322 Danwol-dong, 380-701 Chungju (Korea, Republic of)

2010-01-25

58

Computational rheology  

CERN Document Server

Modern day high-performance computers are making available to 21st-century scientists solutions to rheological flow problems of ever-increasing complexity. Computational rheology is a fast-moving subject - problems which only 10 years ago were intractable, such as 3D transient flows of polymeric liquids, non-isothermal non-Newtonian flows or flows of highly elastic liquids through complex geometries, are now being tackled owing to the availability of parallel computers, adaptive methods and advances in constitutive modelling.Computational Rheology traces the development of numerical methods fo

Owens, RG

2002-01-01

59

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 thae, transparent and free-standing films that were characterized by measurements of conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry.

60

Synthesis of polymer gel electrolyte with high molecular weight poly(methyl methacrylate)-clay nanocomposite  

Energy Technology Data Exchange (ETDEWEB)

Polymer nanocomposite gel electrolytes consisting of high molecular weight poly(methyl methacrylate) PMMA-clay nanocomposite, ethylene carbonate (EC)/propylene carbonate (PC) as plasticizer, and LiClO{sub 4} electrolyte are reported. Montmorillonite clay was ion exchanged with a zwitterionic surfactant (octadecyl dimethyl betaine) and dispersed in methyl methacrylate, which was then polymerized to synthesize PMMA-clay nanocomposites. The nanocomposite was dissolved in a mixture of EC/PC with LiClO{sub 4}, heated and pressed to obtain polymer gel electrolyte. X-ray diffraction (XRD) of the gels indicated intercalated clay structure with d-spacings of 2.85 and 1.40 nm. In the gel containing plasticizer, the clay galleries shrink suggesting intercalation rather than partial exfoliation observed in the PMMA--clay nanocomposite. Ionic conductivity varied slightly and exhibited a maximum value of 8 x 10{sup -4} S/cm at clay content of 1.5 wt. %. The activation energy was determined by modeling the conductivity with a Vogel-Tamman-Fulcher expression. The clay layers are primarily trapped inside the polymer matrix. Consequently, the polymer does not interact significantly with LiClO{sub 4} electrolyte as shown by FTIR. The presence of the clay increased the glass transition temperature (Tg) of the gel as determined by differential scanning calorimetry. The PMMA nanocomposite gel electrolyte shows a stable lithium interfacial resistance over time, which is a key factor for use in electrochemical applications. (Author)

Meneghetti, Paulo; Qutubuddin, Syed [Case Western Reserve Univ., Dept. of Chemical Engineering, Cleveland, OH (United States); Webber, Andrew [Eveready Battery Co., Westlake, OH (United States)

2004-10-30

 
 
 
 
61

Synthesis of polymer gel electrolyte with high molecular weight poly(methyl methacrylate)-clay nanocomposite  

International Nuclear Information System (INIS)

Polymer nanocomposite gel electrolytes consisting of high molecular weight poly(methyl methacrylate) PMMA-clay nanocomposite, ethylene carbonate (EC)/propylene carbonate (PC) as plasticizer, and LiClO4 electrolyte are reported. Montmorillonite clay was ion exchanged with a zwitterionic surfactant (octadecyl dimethyl betaine) and dispersed in methyl methacrylate, which was then polymerized to synthesize PMMA-clay nanocomposites. The nanocomposite was dissolved in a mixture of EC/PC with LiClO4, heated and pressed to obtain polymer gel electrolyte. X-ray diffraction (XRD) of the gels indicated intercalated clay structure with d-spacings of 2.85 and 1.40 nm. In the gel containing plasticizer, the clay galleries shrink suggesting intercalation rather than partial exfoliation observed in the PMMA-clay nanocomposite. Ionic conductivity varied slightly and exhibited a maximum value of 8 x 10-4 S/cm at clay content of 1.5 wt.%. The activation energy was determined by modeling the conductivity with a Vogel-Tamman-Fulcher expression. The clay layers are primarily trapped inside the polymer matrix. Consequently, the polymer does not interact significantly with LiClO4 electrolyte as shown by FTIR. The presence of the clay increased the glass transition temperature (Tg) of the gel as determined by differential scanning calorimetry. The PMMA nanocomposite gel electrolyte shows a stable lithium interfacial resistance over time, which is a erfacial resistance over time, which is a key factor for use in electrochemical applications

62

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

63

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

64

Spray pyrolytic synthesis and electrolytic properties of BiCuVOx films for fuel cell applications  

International Nuclear Information System (INIS)

The fuel cell material of bismuth copper vanadium oxide (BICUVOX) were deposited in thin film form on glass substrates using spray pyrolysis technique. The substrate temperature, quantity of sprayed solution and annealing temperature were charged to study the structural and electrolytic properties of BICUVOX thin films for fuel cell applications. It has been observed that the changes in spray parameters can be used to monitor the electrical properties of BICUVOX thin films suitable for their potential application as electrolyte for solid oxide fuel cell. It is found that the onset of the ionic conductivity region shifts to low temperature region of the fuel cell operating temperature with increase in substrate temperature of the films. (author)

65

Synthesis of new solid polymer electrolyte and actuator based on PEDOT/NBR/ionic liquid  

Science.gov (United States)

The conducting polymer actuator was presented. The solid polymer electrolyte based on nitrile rubber (NBR) activated with different ionic liquids was prepared. The three different grades of NBR films were synthesized by emulsion polymerization with different amount of acrylonitrile, 23, 35, and 40 mol. %, respectively. The effect of acrylonitrile content on the ionic conductivity and dielectric constant of solid polymer electrolytes was characterized. A conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), was synthesized on the surface of the NBR layer by using a chemical oxidation polymerization technique, and room temperature ionic liquids (RTIL) based on imidazolium salts, e.g. 1-butyl-3-methyl imidazolium X [where X= BF 4 -, PF 6 -, (CF 3SO II) IIN -], were absorbed into the composite film. The effects of the anion size of the ionic liquids on the displacement of the actuator were examined. The displacement increased with increasing the anion-size of the ionic liquids.

Cho, M. S.; Seo, H. J.; Nam, J. D.; Choi, H. R.; Koo, J. C.; Lee, Y.

2006-03-01

66

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 i 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.

67

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

Directory of Open Access Journals (Sweden)

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

68

Synthesis and Properties of Acyclic Ammonium-based Ionic Liquids with Allyl Substituents as Electrolytes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several new acyclic ammonium-TFSI ionic liquids with an allyl substituent(s) were synthesized and their physicochemical and electrochemical properties were characterized. [AAMM]Am-TFSI (3) with two allyl groups showed the widest electrochemical stability window (5.9 V) among the ammonium-based ILs reported to date because of the increment of both the anodic and cathodic limits. The charge-discharge performance of a LiCoO2-based half-cell containing [AAMM]Am-TFSI as an electrolyte was better i...

Young Gyu Kim; Oh, Seung M.; Junyoung Mun; Chang Young Choi; Taeeun Yim

2009-01-01

69

Synthesis and Properties of Acyclic Ammonium-based Ionic Liquids with Allyl Substituents as Electrolytes  

Directory of Open Access Journals (Sweden)

Full Text Available Several new acyclic ammonium-TFSI ionic liquids with an allyl substituent(s were synthesized and their physicochemical and electrochemical properties were characterized. [AAMM]Am-TFSI (3 with two allyl groups showed the widest electrochemical stability window (5.9 V among the ammonium-based ILs reported to date because of the increment of both the anodic and cathodic limits. The charge-discharge performance of a LiCoO2-based half-cell containing [AAMM]Am-TFSI as an electrolyte was better in cycleability (the capacity retention ratio: 99% after 20 cycles than that of the cell with the corresponding partially saturated analogue, [AMMP]Am-TFSI (2 (the capacity retention ratio: 92% after 20 cycles.

Young Gyu Kim

2009-05-01

70

Design, synthesis, and testing of potential antisickling agents. 6. Rheologic studies with active phenoxy and benzyloxy acids.  

Science.gov (United States)

In vitro rheologic studies have been performed with homozygous sickle erythrocytes in the presence of phenoxy and benzyloxy antigelling agents. The results correlate with those obtained previously from a standard hemoglobin S solubility assay (C-sat) that monitors the inhibition of hemoglobin S polymerization in solution. The order of activity of compounds in both studies was found to be about the same. The rheologic assay monitors the reduction in pressure (130 mm Hg sickled vs 9 mm Hg nonsickled) needed to push erythrocytes through a 5 micron filter. Among the drugs studied, the antilipidemic drug Clofibrate reduced the filtration pressure by as little as 9%, and a derivative of the diuretic agent ethacrynic acid (Merck-595, 595) reduced it by as much as 94%. Human Serum Albumin (HSA) (0.1% wt/vol) drastically reduced the activity of the noncovalently-acting aromatic acids by requiring at least three times the concentration of drug to obtain similar reductions in pressure. Two covalently-acting compounds, ethacrynic acid and Merck-595, 595, strongly increased the filterability of homozygous S erythrocytes at 1 and 3 mM drug concentrations even in the presence of HSA. No reason is given for the strong inhibitory effect of HSA at such high drug to HSA concentrations. PMID:3651614

Patwa, D C; Abraham, D J; Hung, T C

1987-01-01

71

Synthesis and modeling of polysiloxane-based salt-in-polymer electrolytes with various additives.  

Science.gov (United States)

The effect of both nanoparticles and low molecular weight borate esters on the ionic conductivity of cross-linked polysiloxanes was systematically investigated by means of measuring conductivity spectra in the impedance regime at temperatures between -30 and 90 degrees C. Salt-in-polymer electrolytes were prepared by dissolving lithium triflate (LiSO(3)CF(3)) in comblike polysiloxanes bearing one methyl and one oligoether side group per silicon. An amount of 10 mol % of the oligoether side groups exhibited a terminal allytrimethoxysilane serving as a cross-linker moiety (T(0.1)OPS). Thus prepared polymer electrolyte membranes were completely amorphous and mechanically stable with an optimum conductivity value of 5.7 x 10(-5) S x cm(-1) at 15 wt % of lithium triflate (LiSO(3)CF(3)) at room temperature (T(0.1)OPS + 15 wt % LiSO(3)CF(3)). Further investigations concerned the influence of additives, i.e., nanosized ceramic fillers (alpha-Al(2)O(3) and SiO(2), up to 10 wt %) as well as two low molecular weight borate esters (tris(2-(2-methoxyethoxy)ethyl) borate (B2) and tris(2-(2-(2-methoxyethoxy)ethoxy)ethyl) borate (B3)) with maximum concentrations of 40 wt % as referred to polysiloxane T(0.1)OPS. The addition of borate esters resulted in a considerable increase of the conductivity, while still maintaining the mechanical stability. Optimum conductivities of 3.7 x 10(-5) and 1.6 x 10(-4) S x cm(-1) were measured for B2 and B3, respectively, at room temperature. A fit of the temperature-dependent DC conductivity by the empirical Vogel-Tammann-Fulcher (VTF) equation showed that there was an increased number density of mobile charge carriers in the case of borate esters as additives. However, the shape of the conductivity spectra in the dispersive regime changed considerably in going from nanoparticles as additives to borate esters. A careful and consistent modeling of the conductivity spectra and of the temperature dependence of the DC conductivity was done within the framework of the MIGRATION concept. The result was that the addition of borate esters to the polymer host most probably increased both number density of mobile charge carriers as well as their mobility. PMID:19845380

Karatas, Y; Banhatti, Radha D; Kaskhedikar, N; Burjanadze, M; Funke, K; Wiemhöfer, Hans-D

2009-11-26

72

Synthesis and rheological investigation of a magnetic fluid using olivary silica-coated iron particles as a precursor  

Energy Technology Data Exchange (ETDEWEB)

A new type of magnetic fluid was prepared by dispersing monodispersed iron-silica (Fe-SiO{sub 2}) composite particles in polyethylene glycol (PEG) 400. The composite particles Fe-SiO{sub 2} were synthesized by hydrogen reduction from {alpha}-Fe{sub 2}O{sub 3}-SiO{sub 2} spheres. Their microstructures were observed by a high-resolution transmission electron microscope (HRTEM) and the magnetism was characterized with a superconducting quantum interference device (SQUID) magnetometer. Both steady-state and dynamic rheological properties of the magnetic fluid under different magnetic fields were studied by using a rheometer. Experimental results show that this magnetic fluid has a relatively high magnetoviscous effect at low shear rates. The yield stress of this material shows an increasing trend with a magnetic flux density. Also, viscoealstic properties of such materials are different from conventional ones.

Gu Rui [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Gong Xinglong [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China)], E-mail: gongxl@ustc.edu.cn; Jiang Wanquan [Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China); Hao Lingyun [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Fuyang Normal College, Fuyang 236032 (China); Xuan Shouhu [Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China); Zhang Zhong [National Center for Nanoscience and Technology, Beijing 100080 (China)

2008-11-15

73

Synthesis and rheological investigation of a magnetic fluid using olivary silica-coated iron particles as a precursor  

International Nuclear Information System (INIS)

A new type of magnetic fluid was prepared by dispersing monodispersed iron-silica (Fe-SiO2) composite particles in polyethylene glycol (PEG) 400. The composite particles Fe-SiO2 were synthesized by hydrogen reduction from ?-Fe2O3-SiO2 spheres. Their microstructures were observed by a high-resolution transmission electron microscope (HRTEM) and the magnetism was characterized with a superconducting quantum interference device (SQUID) magnetometer. Both steady-state and dynamic rheological properties of the magnetic fluid under different magnetic fields were studied by using a rheometer. Experimental results show that this magnetic fluid has a relatively high magnetoviscous effect at low shear rates. The yield stress of this material shows an increasing trend with a magnetic flux density. Also, viscoealstic properties of such materials are different from conventional ones

74

Synthesis of polymeric pour point depressants for Nada crude oil (Gujarat, India) and its impact on oil rheology  

Energy Technology Data Exchange (ETDEWEB)

Five flow improvers have been synthesized to study rheological properties of Nada crude oil (Gujarat, India). Anhydride copolymers were prepared making use of the copolymerization of acrylates of different alkyls with maleic anhydride and the Poly (n-alkyl acrylates-co-N-hexadecylmaleimide) were prepared by the reaction of copolymer with hexadecylamine. The additives were purified and characterized by FTIR, GPC. The prepared polymeric additives shows dual function both as wax dispersants and flow improvers and all of them acts as good pour point depressants. Yield stress and the viscosity of the crude oil at different temperatures and concentrations of additives were evaluated by zero friction advanced rheometer AR-500 of TA instrument. Comparison of morphologies and structures of wax crystals or aggregates in waxy crude oils beneficiated with and without a PPD was also done by micro photographic studies which show the modification in wax crystal morphology due to additives. (author)

Deshmukh, Srushti; Bharambe, D.P. [Department of Applied Chemistry, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Kalabhavan, VADODARA-390 001, Gujarat (India)

2008-03-15

75

Synthesis of coral-like tantalum oxide films via anodization in mixed organic-inorganic electrolytes.  

Science.gov (United States)

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 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%. PMID:23799106

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

2013-01-01

76

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 6 M 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 cm2 s-1. Further, electrochemical impedance studies confirmed that the ?-Ni(OH)2 electrode reaction processes are diffusion controlled.

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

2015-01-01

77

Effect of process medium on the synthesis of carbon coated lithium vanadium phosphate composite using rheological phase reaction method  

Science.gov (United States)

Li3V2(PO4)3/C composites (LVP/C) are synthesized by rheological phase reaction (RPR) method using alginic acid (HAlg) as the carbon source. Different process media are applied in the synthetic process to assess the possible effects on LVP/C composite. And the whole synthetic route is discussed in detail with qualitative and instrumental analysis, in terms of ball-milling process, rheology phase reaction process and thermogravimetric analysis of precursors. The much different morphological properties of as-prepared LVP/C composites demonstrate that process medium indeed has some effects on the synthetic process, especially on the refinement and dispersion of particles. According to these investigations, ethylene glycol (EG) is revealed more proper for preparing LVP/C using this method attributed to its moderate viscosity, surface activity and synergistic effects with HAlg. The corresponding LVP/C composite shows nanoscaled particles with smooth surfaces and uniform size distribution. Besides, LVP-EG sample exhibits excellent electrochemical performances under different voltage windows as well. Between 3.0 and 4.3 V, when charge/discharge at 20/50 C, the composite exhibits relatively high capacity and stable cycling performance for 300 cycles. Within 3.0-4.8 V, it can cycle for 200 times at a high rate of 20 C without obvious capacity fading. The outstanding performances can be attributed to the enhanced electronic/ionic conductivities of LVP/C benefitting from the influences of EG and HAlg via the RPR method.

Wu, Yue; Zhao, Xiaoming; Song, Zhihao; Lin, Liping; Du, Chenqiang; Tang, Zhiyuan

2015-01-01

78

Synthesis of LiNi0.65Co0.25Mn0.1O2 as cathode material for lithium-ion batteries by rheological phase method  

International Nuclear Information System (INIS)

Research highlights: ? In this paper, for the first time, rheological phase method, a simple and effective route, was applied to synthesis high capacity cathode material LiNi0.65Co0.25Mn0.1O2. ? All of the results obtained by X-ray diffraction spectrometer, X-ray photoelectron spectrometer, charge-discharge tests and electrochemical impedance spectroscopy show that the rheological phase production have better properties than that of the report. - Abstract: Rheological phase (RP) method has been successfully applied to synthesize a promising cathode material LiNi0.65Co0.25Mn0.1O2. X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma and transmission electron microscope are used to investigate the structure, composition and morphology, respectively. XRD result shows that the as-prepared powder has a layered ?-NaFeO2 structure. XPS pattern reveals that the Ni ions have valences of 2+ and 3+, and the Co and Mn are 3+, 4+, respectively. The electrode consisting of the obtained powder presents the better electrochemical properties, which is attributed to the fewer amounts of Ni2+ ions and the smaller particles. All the results suggest that the rheological phase method is a promising technique for the preparation of LiNi0.65Co0.25Mn0.1O2 cathode material of lithium-ion batteries.f lithium-ion batteries.

79

The preparation of some novel electrolytes: synthesis of partially fluorinated alkane sulfonic acids as potential fuel cell electrolytes. Interim technical report  

Energy Technology Data Exchange (ETDEWEB)

The objective of this research was to prepare some strong acids for evaluation by Fort Belvoir as potential fuel cell electrolytes. The only acid other than phosphoric, H/sup 3/PO/sup 4/, currently under investigation by Fort Belvoir as a fuel cell electrolyte is TFMSA, CF/sup 3/SO/sup 3/H.H/sup 2/O, trifluoromethanesulfonic acid monohydrate aqueous solutions and sodium salt mixtures. TFMSA has been found to be superior to H/sup 3/PO/sup 4/ from the standpoint of electrode kinetics, but certain undesirable characteristics (volatility; wetting of Teflon) led to this search for a better fuel cell electrolyte. The following acids were prepared: Methanedisulfonic acid; Ethanesulfonic acid; Ethane-1,2-disulfonic acid; Propane-1,3-disulfonic acid; Propane-1,2,3-trisulfonic acid; Chlorotrifluoroethanesulfonic acid; and 1,2,2-trifluoroethane-1,1,2-trisulfonic acid. Yields were low because of purification difficulties and future work will be concerned with scaling up the preparations.

Bunyagidj, C.; Aldridge, M.H.

1978-03-01

80

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

Directory of Open Access Journals (Sweden)

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

 
 
 
 
81

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 iPO3)0.5 superionic increased from 2.5 x 10-3 S/cm to 1.143 S/cm. (author)

82

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

2011-12-01

83

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)

84

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

85

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

86

Rheology and deep tectonics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 dyn...

Ranalli, G.

1997-01-01

87

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.

88

Electrolytic cell  

Science.gov (United States)

An apparatus is described for the separation of the anolyte and the catholyte during electrolysis. The electrolyte flows through an electrolytic cell between the oppositely charged electrodes. The cell is equipped with a wedge-shaped device, the tapered end is located between the electrodes on the effluent side of the cell. The wedge diverts the flow of the electrolyte to either side of the wedge, substantially separating the anolyte and the catholyte.

Bullock, J. S.; Hale, B. D.

1984-09-01

89

Ce0.8Sm0.2O1.9 synthesis for solid oxide fuel cell electrolyte by ultrasound assisted co-precipitation method.  

Science.gov (United States)

In this study, the synthesis of Ce(0.8)Sm(0.2)O(1.9) (SDC) solid electrolyte by the ultrasound assisted co-precipitation method was accomplished to explore the effects of ultrasound power, ultrasound pulse ratio and probe type upon the ionic conductivity of SDC as well as the lattice parameter, the microstructure and the density. Fine powders of uniform crystallite sizes (average 11.70±0.62nm) were obtained, needing lower sintering temperature. The SDC powders were successfully sintered to a relative density of over 95% at 1200°C (5°Cmin(-1)) for 6h. The micrograph of SDC pellets showed non-agglomerated and well-developed grains with average size of about 200nm. X-ray diffraction analysis showed that the lattice parameter increased with increasing acoustic intensity and reached a maximum for the 14.94Wcm(-2). Further, a linear relationship was detected between the lattice parameter and the ionic conductivity, inspiring a dopant like effect of US on the electrolyte properties. The highest ionic conductivity as ?(800°C)=3.07×10(-2)Scm(-1) with an activation energy E(a)=0.871kJmol(-1) was obtained with pulsed ultrasound for an acoustic intensity of 14.94Wcm(-2), using 19mm probe and 8:2 pulse ratio. PMID:23178079

Okkay, Hikmet; Bayramoglu, Mahmut; Faruk Öksüzömer, M

2013-05-01

90

Role of interfacial rheological properties in oil field chemistry  

Energy Technology Data Exchange (ETDEWEB)

Interfacial rheological properties of different Hungarian crude oil/water systems were determined in wide temperature and shear rate range and in presence of inorganic electrolytes, tensides, alkaline materials and polymers. The detailed laboratory study definitely proved that the interfacial rheological properties are extremely sensitive parameters towards the chemical composition of inmiscible formation liquids. Comparison and interpretation of the interfacial rheological properties may contribute significantly to extension of the weaponry of the reservoir characterization, better understanding of the displacement mechanism, development of the more profitable EOR/IOR methods, intensification of the surface technologies, optimization of the pipeline transportation and improvement of the refinery operations. It was evidenced that the interfacial rheology is an efficient and powerful detection technique, which may enhance the knowledge on formation, structure, properties and behaviour of interfacial layers. 17 refs., 18 figs., 2 tabs.

Lakatos-Szabo, J.; Lakatos, I.; Kosztin, B.

1996-12-31

91

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 (PGSp>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.

92

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

93

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

94

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

95

Rheology of the Cytoskeleton  

Science.gov (United States)

The cytoskeleton is the primary internal structure of the cell, providing its structural integrity. The rheology and mechanics of the cytoskeleton, therefore, are key to the cell's ability to accomplish its diverse functions in health and disease. Although the importance of the cytoskeleton is well established, the relationship between the microstructural details and the macroscopic rheological behavior of the cytoskeleton remains elusive. A wide range of computational and phenomenological models as well as experimental techniques have been proposed over the past two decades to describe the cytoskeleton, giving rise to several, often contradictory, theories for describing its rheology. This concise review attempts to bring together the key experimental methods and theoretical and computational models regarding cytoskeletal rheology and mechanics.

Mofrad, Mohammad R. K.

2009-01-01

96

Influence of arc duration time on the synthesis of carbon nanohorns by a gas-injected arc-in-water system: application to polymer electrolyte fuel cell electrodes  

International Nuclear Information System (INIS)

Single-walled carbon nanohorns (SWCNH) can be synthesized by a gas-injected arc-in-water (GI-AIW) method at low cost. This study revealed the influence of arc discharge duration time on the yield of SWCNH in the synthesis using this method. As a result, the yield of SWCNH increased with the arc discharge duration time, while an increase in arc plasma temperature was observed. This result can be explained by considering that the increased temperature of the reaction zone can lead to an increase in carbon radical density, which can positively affect the production yield. Here, two arc discharge modes, continuous and discrete, were generated so that modes having different temperatures with the same discharge current could be compared. From this investigation, it was suggested that an excessive ion density may cause a decrease in SWCNH production. The as-grown SWCNH possessed a high specific surface area when the arc discharge current was optimized with continuous arc mode using the GI-AIW method. Such a product can support Pt catalyst with high dispersivity, leading to high performance in polymer electrolyte fuel cells as catalyst layers.

97

Synthesis of amorphous silica and sulfonic acid functionalized silica used as reinforced phase for polymer electrolyte membrane  

International Nuclear Information System (INIS)

In this work silica (SiO2) and sulfonic acid-functionalized silica (sul-SiO2) were synthesized by sol–gel method from tetraethoxysilane (TEOS) and 3-mercatopropyltrimethoxysilane (MPTMS) with various ratios between them. The synthesized materials were characterized by x-ray diffraction (XRD) for crystalline structure, Brunauer–Emmet–Teller (BET) specific surface area analysis, transmission electronic microscopy (TEM) and dynamic light scattering (DLS) for particle size analysis, and ion exchange capacity (IEC) for determining sulfur content in Sul-SiO2 materials. The initial results showed that the average particle size of amorphous SiO2 and Sul-SiO2 at different TEOS: MPTMS ratios are in narrow distribution with average diameter about 20–30 nm. The particle size of Sul-SiO2 is almost unaffected by the content of MPTMS while IEC depends strongly on it. Composite membranes of 60 ?m thickness were successfully prepared from blending of poly(vinylidene fluoride) (PVDF) and synthesized amorphous SiO2. It was shown that the latter may be used as a reinforced phase for composite membrane electrolytes based on PVDF. (paper)

98

Electrolytic preparation of lanthanide and actinide hexaborides using a molten, cryolite-base electrolyte  

International Nuclear Information System (INIS)

Lanthanide and actinide hexaborides are electrolytically synthesized using a molten salt electrolyte containing a major portion of cryolite and minor portions of an alkali borate and a source compound to supply the lanthanide or actinide metal. Minor amounts of an alkali hydroxide or carbonate added to the electrolyte tend to improve product recovery and purity. The synthesis may be accomplished in a cell open to the atmosphere to produce highly pure lanthanide and actinide hexaborides. (auth)

99

Rheological phase reaction synthesis and electrochemical performance of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/carbon cathode for lithium ion batteries  

Energy Technology Data Exchange (ETDEWEB)

Monoclinic lithium vanadium phosphate/carbon (Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C) cathode has been synthesized for applications in lithium ion batteries, via a rheological phase reaction (RPR) method. The sample is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). This material exhibits high initial discharge capacity of 189 and 177 mAh g{sup -1} at 0.1 and 0.2 C between 3.0 and 4.8 V, respectively. Moreover, it displays good fast rate performance, which discharge capacities of 140, 133, 129 and 124 mAh g{sup -1} can be delivered after 100 cycles between 3.0 and 4.8 V vs. Li at a different rate of 0.5, 1, 2 and 5 C, respectively. The electrochemical impedance spectroscopy (EIS) is also investigated. (author)

Chang, Caixian; Xiang, Jiangfeng; Shi, Xixi; Han, Xiaoyan; Yuan, Liangjie; Sun, Jutang [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

2008-01-01

100

Rheological phase reaction synthesis and electrochemical performance of Li3V2(PO4)3/carbon cathode for lithium ion batteries  

International Nuclear Information System (INIS)

Monoclinic lithium vanadium phosphate/carbon (Li3V2(PO4)3/C) cathode has been synthesized for applications in lithium ion batteries, via a rheological phase reaction (RPR) method. The sample is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). This material exhibits high initial discharge capacity of 189 and 177 mAh g-1 at 0.1 and 0.2 C between 3.0 and 4.8 V, respectively. Moreover, it displays good fast rate performance, which discharge capacities of 140, 133, 129 and 124 mAh g-1 can be delivered after 100 cycles between 3.0 and 4.8 V vs. Li at a different rate of 0.5, 1, 2 and 5 C, respectively. The electrochemical impedance spectroscopy (EIS) is also investigated

 
 
 
 
101

Rheological phase reaction synthesis and electrochemical performance of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/carbon cathode for lithium ion batteries  

Energy Technology Data Exchange (ETDEWEB)

Monoclinic lithium vanadium phosphate/carbon (Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C) cathode has been synthesized for applications in lithium ion batteries, via a rheological phase reaction (RPR) method. The sample is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). This material exhibits high initial discharge capacity of 189 and 177 mAh g{sup -1} at 0.1 and 0.2 C between 3.0 and 4.8 V, respectively. Moreover, it displays good fast rate performance, which discharge capacities of 140, 133, 129 and 124 mAh g{sup -1} can be delivered after 100 cycles between 3.0 and 4.8 V vs. Li at a different rate of 0.5, 1, 2 and 5 C, respectively. The electrochemical impedance spectroscopy (EIS) is also investigated.

Chang Caixian; Xiang Jiangfeng; Shi Xixi; Han Xiaoyan; Yuan Liangjie [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Sun Jutang [Department of Chemistry, Wuhan University, Wuhan 430072 (China)], E-mail: jtsun@whu.edu.cn

2008-01-01

102

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

103

Cryogenic electrolytes  

International Nuclear Information System (INIS)

The emphasis is made on experimentally observed indications of the presence of metastable ion dipoles in solid helium. Similar quasiparticles possessing positive scattering length for injected electrons are assumed to exist in liquid phases of cryogenic liquids. The observed phenomena allowing to detect and monitor the behavior of dipole gas in superfluid helium (referred to as cryogenic electrolyte) are discussed. Most interesting among these phenomena are: special features of the dielectric behavior of ion dipole gas, details of the temperature dependence of the ion dipole gas osmotic pressure at the boundary of the liquid 3He-4He solution stratification, relaxation phenomena of collective origin in cryogenic electrolytes, and liquid helium phonon spectrum transformation due to strong interaction between phonons and heavy dipole quasiparticles.

104

Rubbery block copolymer electrolytes for solid-state rechargeable lithium batteries  

Energy Technology Data Exchange (ETDEWEB)

For nearly 20 years, poly(ethylene oxide)-based materials have been researched for use as electrolytes in solid-state rechargeable lithium batteries. Technical obstacles to commercialize derive from the inability to satisfy simultaneously the electrical and mechanical performance requirements: high ionic conductivity along with resistance to flow. Herein, the synthesis and characterization of a series of poly(lauryl methacrylate)-b-poly[oligo(oxyethylene) methacrylate]-based block copolymer electrolytes (BCEs) are reported. With both blocks in the rubbery state (i.e., having glass transition temperatures well below room temperature) these materials exhibit improved conductivities over those of glassy-rubbery block copolymer systems. Dynamic rheological testing verifies that these materials are dimensionally stable, whereas cyclic voltammetry shows them to be electrochemically stable over a wide potential window, i.e., up to 5 V at 55 C. A solid-state rechargeable lithium battery was constructed by laminating lithium metal, BCE, and a composite cathode composed of particles of LiAl{sub 0.25}Mn{sub 0.75}O{sub 2} (monoclinic), carbon black, and graphite in a BCE binder. Cycle testing showed the Li/BCE/LiAl{sub 0.25}Mn{sub 0.75}O{sub 2} battery to have a high reversible capacity and good capacity retention. Li/BCE/Al cells have been cycled at temperatures as low as {minus}20 C.

Soo, P.P.; Huang, B.; Jang, Y.I.; Chiang, Y.M; Sadoway, D.R.; Mayes, A.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

1999-01-01

105

Utilization of the secondary energy of Itaipu, Parana State, Brazil, for electrolytical ammonia production for nitrogenous fertilizers synthesis; Utilizacao da energia secundaria da usina hidreletrica de Itaipu, PR, Brasil para producao de amonia eletrolitica para sintese de fertilizantes nitrogenados  

Energy Technology Data Exchange (ETDEWEB)

Secondary energy can be described as a surplus of electrical energy in hydraulic power plant due to the lower demand of energy during some periods of time, and the excess of water in the reservoir, during rainy periods. The largest hydroelectric power plant both in Brazil and South America is Itaipu, jointly operated by Brazil and Paraguay. This power plant has a large amount of secondary energy available, and this energy is lost as no turbine spilled water out of the reservoir. This study proposes the using of this energy for electrolytic hydrogen production and ammonia for nitrogenous fertilizers. The hydrogen is produced as a gas by mean of electrolyses and with the atmospheric nitrogen for the electrolytic ammonia synthesis, used as the most important raw material for the nitrogen fertilizers synthesis. This study performs the determination of the minimal cost of hydrogen production and the correspondent hydrogen production capacity in accordance with the ammonia market for nitrogenated fertilizers in the Center/South region, estimating the better production capacity for an ammonia plant to be installed close to Itaipu.

Souza, S.N.M. de; Siqueira, J.A.C.

2000-07-01

106

Rheology of aqueous foams  

Science.gov (United States)

Aqueous foams are suspensions of bubbles inside aqueous phases. Their multiphasic composition leads to a complex rheological behavior that is useful in numerous applications, from oil recovery to food/cosmetic processing. Their structure is very similar to the one of emulsions, so that both materials share common mechanical properties. In particular, the presence of surfactants at the gas-liquid interfaces leads to peculiar interfacial and dissipative properties. Foam rheology has been an active research topics and is already reported in several reviews, most of them covering rheometry measurements at the scale of the foam, coupled with interpretations at the local scale of bubbles or interfaces. In this review, we start following this approach, then we try to cover the multiscale features of aqueous foam flows, emphasizing regimes where intermediate length scales need to be taken into account or regimes fast enough regarding internal time scales so that the flow goes beyond the quasi-static limit. xml:lang="fr"

Dollet, Benjamin; Raufaste, Christophe

2014-10-01

107

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

108

Rheology of calciium sulfate suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work has been initiated to improve the development of mineral suspension used for building construction. In this industrial field, the rheological evolution needs to be controlled from the mixing to the setting up. The study is herein focused on the influence of polycarboxylates superplasticizers as additives on the rheological properties of suspensions made with a reactive anhydrite. Firstly, we develop some protocols of rheological characterization which have been calibrated using a mo...

Pierre, Alexandre

2013-01-01

109

Modeling pulp fiber suspension rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheological properties of pulp suspensions play a very important role in the industry, mainly due to the consumption of energy for transporting pulp among the different parts of the paper mill. In this work, we determined the rheology of long- and short-fiber bleached kraft pulp suspensions by using a new rotational viscometer especially designed for their analysis. The experimental rheograms were adjusted to the Herschel-Bulkley model. We established the dependence of the rheological p...

Ventura, Carla; Blanco, Angeles; Negro, Carlos; Ferreira, Paulo; Garcia, Fernando; Rasteiro, Maria

2007-01-01

110

Experiments on Paint Rheology  

Science.gov (United States)

We seek a better understanding of the atomization of paints for purposes of limiting the environmental impact of spray painting. However, to do so one must confront both the shear and extensional rheology of mobile non-Newtonian fluids whose very composition is often complex and even unknown. A conventional Couette rheometer yields data on paint shear behavior, but no commercial instrument is available to measure the extensional viscosity, which is believed to govern ligamentary breakup in spray painting. Here a converging-flow extensional rheometer has been built for this purpose. Flow rate and orifice pressure drop are measured and related to the rheological properties of the fluid. At first, experience was gained by visualizing in this device the flow of clear aqueous solutions of both Newtonian (glycerol) and non-Newtonian (polyacrylamide) thickeners. Commercial latex and marine paints were then tested, with the goal of characterizing their extensional behavior and the hope that they might be replaceable by simpler aqueous rheological "substitute" fluids insofar as their atomization behavior is concerned. (Research supported by the US Navy via the Penn State Applied Research Laboratory.)

Hartranft, Thomas J.; Settles, Gary S.

1998-11-01

111

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

112

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)

113

Hydrothermal synthesis of carbon/vanadium dioxide core-shell microspheres with good cycling performance in both organic and aqueous electrolytes  

International Nuclear Information System (INIS)

Carbon/vanadium dioxide (C/VO2(B)) core-shell microspheres were prepared by a one-step hydrothermal process and characterized by X-ray diffraction and scanning electron microscopy. The electric cycling performance of C/VO2(B) in organic and LiCl aqueous electrolytes was evaluated by the galvanostatic method and by cyclic voltammetry, respectively. The results showed that the product had very stable cycling performance in both types of electrolytes compared to pure VO2(B).

114

The rheology of caramel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rheology of caramel was determined as a function of processing temperature and hydrocolloid additions. As the processing temperature increased the water content decreased and the caramel viscosity increased. X-ray diffraction showed that although crystalline fat was present, for the most part the sugars were in the amorphous state. The exception was the lowest water content caramel (7.9% water w.w.b.) which had been processed to a temperature of 122ºC. This had a small amount of crystall...

Barra, Giuseppina

2004-01-01

115

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)

116

Fuel cell having electrolyte  

Science.gov (United States)

A fuel cell having an electrolyte control volume includes a pair of porous opposed electrodes. A maxtrix is positioned between the pair of electrodes for containing an electrolyte. A first layer of backing paper is positioned adjacent to one of the electrodes. A portion of the paper is substantially previous to the acceptance of the electrolyte so as to absorb electrolyte when there is an excess in the matrix and to desorb electrolyte when there is a shortage in the matrix. A second layer of backing paper is positioned adjacent to the first layer of paper and is substantially impervious to the acceptance of electrolyte.

Wright, Maynard K. (Bethel Park, PA)

1989-01-01

117

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

118

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

119

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 sh...

Endang Sulistyowati; Harso Pawignyo; Purwo Subagyo; Eniya Listiani Dewi; Tjukup Marnoto; Mahreni Mahreni

2011-01-01

120

Rheology of Monodisperse Emulsions  

Science.gov (United States)

We have conducted an extensive investigation of the rheology of monodisperse emulsions which have a uniform droplet size and are highly controllable. Their rheological behavior ranges from purely viscous to highly elastic depending on the degree of deformation of the droplet interfaces. We have made the first measurements of their osmotic pressure and shear elasticity as a function of droplet size, volume fraction, and viscosity from weak to strong droplet compression limits. We find a remarkable similarity in the volume fraction dependence of the shear modulus and the osmotic pressure which has not been previously observed. We attribute this to the coupling of transverse shear and osmotic compression of droplets within the emulsion. Using optical and mechanical techniques, we have measured the linear shear viscoelastic susceptibility of a compressed emulsion over nine orders of magnitude in frequency. To compare with emulsions, which have deformable droplet interfaces, we have measured the frequency dependence of the linear shear viscoelasticity of concentrated hard spheres. This spectrum shows high and low frequency viscous relaxations with a dominant elasticity at intermediate frequencies. We have developed a theory for the observed spectrum which incorporates mode coupling theories of glassy dynamics with diffusional boundary layer theories. This is the first observation of the consequences of the glass transition in the viscoelasticity of hard sphere suspensions and is the first application of mode coupling theory to their rheology. Finally, we have also developed a novel light scattering technique to measure the frequency dependent viscoelastic moduli of complex fluids. This establishes a very general framework connecting the average microscopic motion of particles suspended in a complex fluid to its bulk viscoelasticity. Because optical techniques can measure particle motion over a large temporal dynamic range, we can determine the viscoelasticity over a similarly broad range in frequencies, including high frequencies which are difficult to achieve with mechanical techniques. This optical technique is suitable for concentrated suspensions and for tracer particles suspended in general complex fluids. With it, we have measured the viscoelasticity of monodisperse emulsions, hard sphere suspensions, and polymeric solutions over a greatly extended frequency range.

Mason, Thomas Graves

1995-01-01

 
 
 
 
121

Solid polymer electrolyte compositions  

Science.gov (United States)

An electrolyte composition is featured that includes a solid, ionically conductive polymer, organically modified oxide particles that include organic groups covalently bonded to the oxide particles, and an alkali metal salt. The electrolyte composition is free of lithiated zeolite. The invention also features cells that incorporate the electrolyte composition.

Garbe, James E. (Stillwater, MN); Atanasoski, Radoslav (Edina, MN); Hamrock, Steven J. (St. Paul, MN); Le, Dinh Ba (St. Paul, MN)

2001-01-01

122

Lithium ion conducting electrolytes  

Science.gov (United States)

The present invention relates generally to highly conductive alkali-metal ion non-crystalline electrolyte systems, and more particularly to novel and unique molten (liquid), rubbery, and solid electrolyte systems which are especially well suited for use with high current density electrolytic cells such as primary and secondary batteries.

Angell, Charles Austen (Mesa, AZ); Liu, Changle (Midland, MI); Xu, Kang (Montgomery Village, MD); Skotheim, Terje A. (Tucson, AZ)

1999-01-01

123

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

124

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

125

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

126

Electro-rheological disk pump  

Science.gov (United States)

The invention is directed to a device for pumping electro-rheological fluids comprising a casing that defines an inner rotor chamber having a central inlet opening and a peripheral discharge opening. Rotatably disposed within said chamber is a rotor for imparting energy to the pumped electro-rheological fluid comprising of a plurality of non-conducting coaxial substantially parallel spaced disks. On one face of each disk are embedded one or more electrodes and on the opposing face of each disk are attached one or more conductive surfaces. By selectively applying an electric charge to the embedded electrodes, an electric field is produced between the electrodes and the conducting surfaces of adjacent disks. As a result, the viscosity of the electro-rheological fluid exposed to the applied electric field is increased thereby producing electro-rheological fluid vanes between adjacent disks. When the rotor is placed in rotation and a voltage is applied to the embedded electrodes, the electro-rheological fluid that is not exposed to the applied electric field, it is accelerated from the center of the rotor towards the outer periphery by the combined action of the electro-rheological fluid vanes and the friction force acting between the fluid and the rotating disks.

Iorio, Vincent M.; Loy, Luke W.

1993-02-01

127

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

128

Rheological characterization of nuclear waste using falling-ball rheometry  

Energy Technology Data Exchange (ETDEWEB)

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.

Abbott, J.R.; Unal, C.; Stephens, T.; Pasamehmetoglu, K.O.; Graham, A.L.; Edwards, J.N.

1994-07-01

129

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

130

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

131

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

132

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

133

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

134

Initial rheological description of high performance concretes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 is 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 rheologic...

Alessandra Lorenzetti de Castro; Jefferson Benedicto Libardi Liborio

2006-01-01

135

Electrolytic purification of metals  

Science.gov (United States)

A method of electrolytically separating metal from impurities comprises providing the metal and impurities in a molten state in a container having a porous membrane therein, the membrane having a thickness in the range of about 0.01 to 0.1 inch, being capable of containing the molten metal in the container, and being permeable by a molten electrolyte. The metal is electrolytically transferred through the membrane to a cathode in the presence of the electrolyte for purposes of separating or removing impurities from the metal.

Bowman, Kenneth A. (Leechburg, PA)

1980-01-01

136

Synthesis of a new electrolyte by co-poly-esters doped with sodium dodecyl sulfate for application on PEM fuel cells  

Energy Technology Data Exchange (ETDEWEB)

Proton exchange membrane fuel cells (PEMFCs) use polymer membranes as electrolytes and protons as conductors. This paper reported on a study in which co-polyesters were doped with sodium dodecyl sulfate. The co-polymers were synthesized by a copolymerization process that used terephthalic and adipic acids with glycerol. A reactor was used to process the material, which was then hot-pressed to produce homogenous and flexible plates. X-ray diffraction (XRD) scanning electron microscopy (SEM), thermogravimetric, direct scanning calorimetry (DSC) and Fourier Transform Infrared (FTIR) analyses were conducted. Results of the analyses demonstrated that the composite material was stable up to a temperature of 250 degrees C. A micrographics study showed that MDS was homogeneously dispersed in the polymeric matrix. It was concluded that with an electrical conductivity between 10-7 to 10-1 S per cm, the copolymers were suitable for use in PEMFC applications.

Fiuza, J.R.A.; Boaventura, F.J.S.; Jose, N.M.; Bresciani, D. [Univ. Federal da Bahia, Salvador (Brazil). Dept. of Physical Chemistry

2009-07-01

137

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

138

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

139

Features of microarc oxidation coatings formation technology in slurry electrolytes  

Science.gov (United States)

A group of electrolytes composed of different powders entered into electrolyte presents a separate direction in microarc oxidation (MAO) technology. This group of electrolytes is most complex and however it has not been sufficiently studied yet. This paper shows that addition of powders of different nature into electrolyte influences both on properties of obtained coatings and on speed of their formation. The MAO-coatings formed in similar electrolytes-suspensions or slurry electrolytes (SE) contain in their composition an essential share of powder material entered into electrolyte as corpuscles of disperse phase (DP). Different nonmetallic combinations are used: oxides, carbides, borides, nitrides of metals and others. The particular conditions of microarc discharge regime (high temperature and pressure in a zone of breakdown) cause a thermolysis of electrolyte together with weighed corpuscles of solid matter, the realization of plasma chemical reactions on oxidizing surface and provide the synthesis of chemical combinations in an oxide matrix. A new composition of slurry electrolyte which allows improving the quality of obtained coatings on the basis of held investigations was developed.

Malyshev, V. N.; Zorin, K. M.

2007-12-01

140

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

 
 
 
 
141

Cavitation Rheology of Polyacrylamide Hydrogels  

Science.gov (United States)

Cavitation rheology is a new characterization technique for the measurement of mechanical properties on small length scales, e.g. 10 -100 ?m, at any arbitrary location within a soft material. The technique involves growing a cavity at the tip of a syringe needle and monitoring the pressure of the cavity at the onset of instability. This critical pressure is directly related to the local modulus of the material. We used this technique to characterize the network mechanics of polyacrylamide hydrogel materials, a common material used in many biological applications. We compared the cavitation rheology results with that obtained from shear rheometry. This technique was used to investigate the rheological properties of gels with different dimensions and different moduli, which were obtained by varying initial monomer to water ratio. These results provide a quantitative foundation for the extension of this technique to in vivo characterization of biological tissues.

Kundu, Santanu; Zimberlin, Jessica; Crosby, Alfred

2008-03-01

142

A facile method for the synthesis of the Li(0.3)La(0.57)TiO? solid state electrolyte.  

Science.gov (United States)

We report a facile method for the synthesis of Li(0.3)La(0.57)TiO3 by forming a coagulated precursor solution which contains Li(+), La(3+), and TiO2 nanoparticles mixed highly homogeneously. The grain and overall conductivities of the synthesized Li(0.3)La(0.57)TiO3 are comparable to the values in literature for the material prepared by other methods. PMID:24728175

Zhang, Qifeng; Schmidt, Nick; Lan, Jolin; Kim, Whungwhoe; Cao, Guozhong

2014-05-30

143

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

144

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

145

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

146

Citrate gel synthesis of aluminum-doped lithium lanthanum titanate solid electrolyte for application in organic-type lithium-oxygen batteries  

Science.gov (United States)

Aluminium doped lithium lanthanum titanate (A-LLTO) powders with various excess Li2O content are synthesized using a simple citrate gel method. The obtained A-LLTO powders show an agglomerated form, composed of nano-sized particles of 20-50 nm. The morphology and conductivity of the A-LLTO ceramics are largely affected by the content of excess Li2O. The highest total ionic conductivity of 3.17 × 10-4 S cm-1 is achieved for the A-LLTO sample containing 20% excess Li2O, exhibiting a vacancy content of 6%, and a total activation energy of 0.358 eV. The A-LLTO can act as a membrane to protect lithium metal from oxygen and other contaminants diffused through the oxygen electrode part. The Li-O2 cell employing the A-LLTO solid electrolyte shows a good cycle life of longer than 100 discharge-charge cycles, under the constant capacity mode of 300 mAh g-1.

Le, Hang T. T.; Kalubarme, Ramchandra S.; Ngo, Duc Tung; Jang, Seong-Yong; Jung, Kyu-Nam; Shin, Kyoung-Hee; Park, Chan-Jin

2015-01-01

147

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

148

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

149

Molecular Rheology of Complex Fluids  

DEFF Research Database (Denmark)

The processing of polymer materials is highly governed by its rheology, and influences the properties of the final product. For example, a recurring problem is instability in extrusion that leads to imperfect plastic parts. The ability to predict and control the rheological behavior of polymer fluids as a function of molecular chemistry has attracted a long history of collaboration between industry and academia. In industrial polymer processes, there is usually a combination of both shear and extensional flows. In some processing operations such as blow molding and fiber spinning, extensional flow is the dominant type of deformation. The polymer molecules experience a significant amount of chain orientation and stretching during these processes. Shear rheology measured by conventional shear rheometers is good at describing chain orientation, whereas extensional rheology gives a good way of inducing chain stretching. Accurate and reliable stress–strain measurements of extensional flow play a crucial role in the understanding of non–linear rheological properties of polymers. However, the non–linear extensional rheology has not been extensively studied. It is known that the rheology of polymer melts is highly sensitive to molecular architecture, but the precise connection between architecture and non–linear rheology is still not fully understood. For example, linear polymer melts have the simplest architecture, but the possible existence of a qualitative difference on extensional steady–state viscosity between melts and solutions is still an open question. Branched polymer melts have more complex molecular structures. A stress maximum during the start–up of uniaxial extensional flow was reported in 1979 for a low–density polyethylene (LDPE) melt. Subsequently observations of a steady stress following a stress maximum were reported for two LDPE melts. However the rheological significance of the stress maximum as well as the existence of steady flow conditions following the maximum is still a matter of some debate. This thesis focuses on the experimental study of extensional rheology of linear and branched polymer melts. We report the stress–strain measurements in extensional flows using a unique Filament Stretching Rheometer (FSR) in controlled strain rate mode and controlled stress mode. Extensional flow is difficult to measure reliably in Laboratory circumstances. In this thesis we first present an updated control scheme that allows us to control the kinematics of polymer melts in an FSR, which is the foundation of our experimental work. Next we investigate four categories of polymer melts from the simplest system to the most complicated system, including 1) the narrow molar mass distribution (NMMD) linear polystyrene melts and solutions; 2) the bidisperse and polydisperse linear polystyrene melts; 3) the NMMD branched polystyrene melts; and 4) the polydisperse branched polyethylene melts. The experimental results are also compared with some developing theoretical models. Finally, to ensure the experimental data is accurate, the measurements from the FSR are compared with the data from some other extensional rheometers as well.

Huang, Qian

2013-01-01

150

Molecular simulation of rheological properties using massively parallel supercomputers  

Energy Technology Data Exchange (ETDEWEB)

Advances in parallel supercomputing now make possible molecular-based engineering and science calculations that will soon revolutionize many technologies, such as those involving polymers and those involving aqueous electrolytes. We have developed a suite of message-passing codes for classical molecular simulation of such complex fluids and amorphous materials and have completed a number of demonstration calculations of problems of scientific and technological importance with each. In this paper, we will focus on the molecular simulation of rheological properties, particularly viscosity, of simple and complex fluids using parallel implementations of non-equilibrium molecular dynamics. Such calculations represent significant challenges computationally because, in order to reduce the thermal noise in the calculated properties within acceptable limits, large systems and/or long simulated times are required.

Bhupathiraju, R.K.; Cui, S.T.; Gupta, S.A.; Cummings, P.T. [Univ. of Tennessee, Knoxville, TN (United States). Dept of Chemical Engineering; Cochran, H.D. [Oak Ridge National Lab., TN (United States)

1996-11-01

151

Sol-Gel Synthesis and Conductivity Properties of Sodium Ion Solid State Electrolytes Na3Zr2Si2PO12  

Directory of Open Access Journals (Sweden)

Full Text Available NASICON-structured Na3Zr2Si2PO12 was synthesized by a Sol-Gel approach. Phase-pure samples were successfully sintered at 1050? when adding 10% excessive Na and P in the precursors, while a small amount of ZrO2 impurity was detected without adding excessive phosphorus. Electrochemical impedance spectrum tests indicate that the ionic conductivity of the former is as high as 5.4×10-4 S/cm at room temperature, which is higher than that of samples prepared from the precursors without adding excessive phosphorus (3.7×10-4 S/cm. Further analysis reveals that the evaporation of phosphorus at high temperature would cause the formation of ZrO2 impurity in the samples, leading to a lower ionic conductivity. Compared with solid state reaction approach, samples with enhanced ionic conductivity can be obtained at a rather lower temperature by Sol-Gel synthesis.

ZHANG Zhi-Zhen, SHI Si-Qi, HU Yong-Sheng, CHEN Li-Quan

2013-11-01

152

Development of New Electrochemical Synthesis of Oxides: Electrolytic Deposition of La2CuO4 Thick Layer on Zirconia Surface in Molten Salt  

Science.gov (United States)

A new method for electrochemical synthesis of oxides in molten salt was developed. The following galvanic cell was assembled and electrolysis was carried out at 973 K between the electrodes LaB6 vs Pt/O2 and between Cu vs Pt/O2 simultaneously. Pt, LaB6 |80%KCl-14%NaCl-(6-x)%LaCl3-x%CuCl2|ZrO2(Y2O3)|O2, Pt Pt, Cu Formation of almost-single-phased La2CuO4 on the ZrO2(Y2O3) surface was confirmed when the ratio of electric currents passed through electrodes LaB6 vs Pt/O2 and Cu vs Pt/O2 was controlled to 3:1.1 and the molten salt composition was fixed at 80%KCl-14%NaCl-6%LaCl3.

Nakamura, Tetsur?; Natsuhara, Masuhiro; Kawaji, Hitoshi; Itoh, Mitsuru

1991-08-01

153

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 Depaain 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.

154

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

155

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

156

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

157

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

158

Solid electrolyte cell  

Science.gov (United States)

A solid electrolyte cell including a body of solid ionized gas-conductive electrolyte having mutually spaced surfaces and on which is deposited a multiplicity of mutually spaced electrodes is described. Strips and of bare substances are interposed between electrodes, so that currents of ionic gas may be established between the electrodes via the bare strips, whereby electrical resistance for the cells is lowered and the gas conductivity is enhanced.

Richter, R.

1982-05-01

159

Capillary Forces in Suspension Rheology  

Science.gov (United States)

The rheology of suspensions (solid particles dispersed in a fluid) is controlled primarily through the volume fraction of solids. We show that the addition of small amounts of a secondary fluid, immiscible with the continuous phase of the suspension, causes agglomeration due to capillary forces and creates particle networks, dramatically altering the bulk rheological behavior from predominantly viscous or weakly elastic to highly elastic or gel-like. This universal phenomenon is observed for a rich variety of particle/liquid systems, independent of whether the second liquid wets the particles better or worse than the primary liquid. These admixtures form stable suspensions where settling would otherwise occur and may serve as a precursor for microporous polymer foams, or lightweight ceramics.

Koos, Erin; Willenbacher, Norbert

2011-02-01

160

Rheology of sedimenting particle pastes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study the local and global rheology of non-Brownian suspensions in a solvent that is not density-matched, leading to either creaming or sedimentation of the particles. Both local and global measurements show that the incomplete density matching leads to the appearance of a critical shear rate above which the suspension is homogenized by the flow, and below which sedimentation or creaming happens. We show that the value of the critical shear rate and its dependence on the ...

Fall, Abdoulaye; Cagny, Henri; Bonn, Daniel; Ovarlez, Guillaume; Wandersman, Elie; Dijksman, Joshua; Hecke, Martin

2013-01-01

 
 
 
 
161

Critical Scaling of Granular Rheology  

Science.gov (United States)

Rheology of dense granular matter in the vicinity of the jamming transition is investigated. Critical scaling laws that describe shear stress, pressure, and kinetic temperature are investigated. The scaling exponents are modified from those previously estimated by the present author [T. Hatano, J. Phys. Soc. Jpn. 77 (2008), 123002]. and also compared with those proposed by Otsuki and Hayakawa [M. Otsuki and H. Hayakawa, Prog. Theor. Phys. 121 (2009), 647].

Hatano, T.

162

Granular Rheology in Zero Gravity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present an experimental investigation on the rheological behavior 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 airplane 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 sh...

Bossis, G.; Grasselli, Y.; Volkova, O.

2003-01-01

163

RHEOLOGICAL PROPERTIES OF MINERAL OIL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

164

Cement with adjustable rheological behavior  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays, cement manufacturers use polymers, called superplastizicers, to enhance cement pastes workability. However, cement suspensions with superplastizicers often become unstable and settle. We showed thermoassociative polymers utilization enables to avoid the settle or decrease the yield stress with temperature change. Rheological measurements have been completed with polymer adsorption data on cement particles. So, we proved that the active part of thermoassociative polymers in the thick...

Noe?l, Marie-he?le?ne

2009-01-01

165

RHEOLOGICAL BEHAVIOUR OF PSYLLIUM GUM FRACTIONS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Psyllium (Plantago psyllium) is a native plant that grows widely in India, Iran and Pinjab. Studies showed psyllium gum has good rheological properties for using in wide range of food products. In this study, different fractions of psyllium gum extracted by water and alkali treatment. Rheological properties of these fractions determined by Brookfield rheometer (RV DVIII). Obtained data fitted in three temperatures 30, 60 and 80°C by Herschel-bulkly rheological model. Results showed that frac...

Mohammad Hojjatoleslamyi; Fatemeh Raisi; Masoumeh AsadiiiMohammad Ali Shariaty

2013-01-01

166

Hybrid inorganic-organic polymer electrolytes: synthesis, FT-Raman studies and conductivity of {Zr[(CH2CH2O)8.7]?/(LiClO4)z}n network complexes  

International Nuclear Information System (INIS)

This paper describes the synthesis and characterization of three-dimensional hybrid inorganic-organic networks prepared by a polycondensation reaction between Zr(O(CH2)3CH3)4 and polyethylene glycol 400 (PEG400). Eleven hybrid networks doped with varying concentrations of LiClO4 salt were prepared. On the basis of analytical data and FT-Raman studies it was concluded that these polymer electrolytes consist of inorganic-organic networks with zirconium atoms bonded together by PEG400 bridges. These polymers are transparent with a solid rubber consistency and are very stable under inert atmosphere. Scanning electron microscopy revealed a smooth glassy surface. X-ray fluorescence microanalysis with energy dispersive spectroscopy demonstrated that all the constituent elements are homogeneously distributed in the materials. Thermogravimetric measurements revealed that these materials are thermally stable up to 262 deg. C. Differential Scanning Calorimetry measurements indicated that the glass transition temperature Tg of these inorganic-organic hybrids varies from -43 to -15 deg. C with increasing LiClO4 concentration. FT-Raman investigations revealed the TGT (T=trans, G=gauche) conformation of polyether chains and allowed characterization of the types of ion-ion and ion-polymer host interactions in the bulk materials. The conductivity of the materials at different temperatures was determined by imifferent temperatures was determined by impedance spectroscopy over the 20 Hz-1 MHz frequency range. Results indicated that the materials conduct ionically and that their ionic conductivity is strongly influenced by the segmental motion of the polymer network and the type of ionic species distributed in the bulk material. Finally, it is to be highlighted that the hybrid network with a nLi/nO molar ratio of 0.0223 shows a conductivity of ca. 1x10-5 S cm-1 at 40 deg. C

167

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

168

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

169

Coal water mixtures: effect on coal particles physicochemical properties and milling mode on suspensions rheology  

Energy Technology Data Exchange (ETDEWEB)

The coal water mixture (CWM) quality is determined by coal physicochemical properties and mode of preparation. High rank coals (bituminous and anthracite) give more concentrated suspensions than low rank coals (high volatile bituminous and lignite). It is attributed to coal rank related properties such as oxygen/carbon ratio (O/C), capacity of water absorption, state of the surface and particles shape. After an adequate additives selection and CWM rheological classification an optimal particle size distribution was investigated for improving suspensions rheological properties, it is characterized by 6% in weight under 1mum and 3% above 200mum or a slope of 0.70 to 0.75 in the Rosin-Rammler graphic. Satisfactory results were obtained by two-stage concentrated pulp milling. This preparation extrapolated into continuous procedure gives optimal particle size distribution and concentrated suspensions with the majority of coals. The improvement recorded is explained by an increase of the spread of the particle size distribution with formation of colloidal particles, transformation of rough to smooth surfaces and particles shape with rounded edges. The pH and viscosity of suspensions vary with time and added electrolytes: optimum pH is between 9 and 10, addition of multivalent cations to concentrated suspensions affects deeply rheology, viscosity depends on cation nature and quantity ratio. Taking in account the compatibility of results between rheological and electrokinetical measurements. The Zeta potential method can be used for selecting ionic additives.

Elomrani, M.

1987-01-01

170

Lithium sulfide compositions for battery electrolyte and battery electrode coatings  

Science.gov (United States)

Method of forming lithium-containing electrolytes are provided using wet chemical synthesis. In some examples, the lithium containing electrolytes 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 of .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, Wujun; Lin, Zhan; Dudney, Nancy J; Howe, Jane Y; Rondinone, Adam J

2014-10-28

171

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

172

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

173

Chocolate rheology Reologia de chocolate  

Directory of Open Access Journals (Sweden)

Full Text Available 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 crystalsReologia 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 reológico, 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

Estela Vidal Gonçalves

2010-12-01

174

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

175

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

176

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

177

Rheology of unstable mineral emulsions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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), ...

Sokolovi? Dunja S.; Še?erov-Sokolovi? Radmila M.; Sokolovi? Slobodan M.

2013-01-01

178

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

179

Conductance of strong electrolytes  

International Nuclear Information System (INIS)

An introduction to the theory of strong electrolytes is presented. The derivation of Onsager's limiting law is presented and five empirical and theoretical conductance equations are given. These are compared with measurements by Chiu and Fouss on KCl and NaCl. APL programs for computing the conductivity from the different equations are listed

180

RHEOLOGIC BEHAVIOR OF PASTRY CREAMS  

Directory of Open Access Journals (Sweden)

Full Text Available The increased social and economic importance of ready–made food production, together with the complexity of production technology, processing, handling and acceptance of these fragile and perishable products requires extensive knowledge of their physical properties. Viscoelastic properties play an important role in the handling and quality attributes of creams.Our study was to investigate the rheological properties of different confectionary creams, by scanning the field of shear rates at constant temperature and frequency, angular frequency scanning at small deformations and quantification of rheological changes during application of deformation voltages. The creams tested were made in the laboratory using specific concentrates as fine powders, marketed by the company “Dr. Oetker” compared with similar creams based on traditional recipes and techniques. Following the researches conducted we could conclude that both traditional creams and the instant ones are semi fluid food products with pseudoplastic and thixotropic shear flow behavior, with structural viscosity. Instant and traditional creams behaved as physical gels with links susceptible to destruction, when subjected to deformation forces.

Camelia Vizireanu

2012-03-01

 
 
 
 
181

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

182

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

183

Electrolytic cell with reference electrode  

Science.gov (United States)

A reference electrode device is provided for a high temperature electrolytic cell used to electrolytically recover uranium from spent reactor fuel dissolved in an anode pool, the device having a glass tube to enclose the electrode and electrolyte and serve as a conductive membrane with the cell electrolyte, and an outer metal tube about the glass tube to serve as a shield and basket for any glass sections broken by handling of the tube to prevent their contact with the anode pool, the metal tube having perforations to provide access between the bulk of the cell electrolyte and glass membrane.

Kessie, Robert W. (Naperville, IL)

1989-01-01

184

Reference electrode for electrolytic cell  

Science.gov (United States)

A reference electrode device is provided for a high temperature electrolytic cell used to electrolytically recover uranium from spent reactor fuel dissolved in an anode pool, the device having a glass tube to enclose the electrode and electrolyte and serve as a conductive membrane with the cell electrolyte, and an outer metal tube about the glass tube to serve as a shield and basket for any glass sections broken by handling of the tube to prevent their contact with the anode pool, the metal tube having perforations to provide access between the bulk of the cell electrolyte and glass membrane.

Kessie, Robert W.

1988-07-01

185

Gel polymer electrolytes for batteries  

Energy Technology Data Exchange (ETDEWEB)

Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

2014-11-18

186

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

187

Effects of size and concentration on the thermals and rheologicals properties of nanofluids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The work presented in this thesis involves the synthesis and thermal and rheological characterization of a new type of nanofluid : the Cu2O/glycerol system. The characterization was carried out as a function of the size of the particles in suspension, the temperature and the volume fraction of nanoparticles. The nanoparticles and nanofluids were synthesised by the thermal decomposition method, providing a good yield of nanoparticles (17%). Apparatus for thermal measurements using the 3? meth...

Hadaoui, Abdellah

2010-01-01

188

Analogy between dynamics of thermo-rheological and piezo-rheological pendulums  

International Nuclear Information System (INIS)

The constitutive stress-strain relations of the standard thermo-rheological and piezo-rheological hereditary element in differential form as well as in two different integro-differential forms are defined. The considered problem of a thermo-rheological hereditary discrete system nonlinear dynamics in the form of thermo-rheological double pendulum system with coupled pendulums gets the significance of two constrained bodies in plane motion problem, as a problem important for studying a sensor dynamics or actuator dynamics in active structure dynamics. System of the averaged equations in the first approximation for amplitudes and phases are derived and qualitatively analyzed. Analogy between nonlinear dynamics of the double pendulum systems with thermo-rheological and piezo-rheological properties between pendulums is pointed out

189

RHEOLOGICAL BEHAVIOUR OF PSYLLIUM GUM FRACTIONS  

Directory of Open Access Journals (Sweden)

Full Text Available Psyllium (Plantago psyllium is a native plant that grows widely in India, Iran and Pinjab. Studies showed psyllium gum has good rheological properties for using in wide range of food products. In this study, different fractions of psyllium gum extracted by water and alkali treatment. Rheological properties of these fractions determined by Brookfield rheometer (RV DVIII. Obtained data fitted in three temperatures 30, 60 and 80°C by Herschel-bulkly rheological model. Results showed that fractions have different behaviour during heating treatment. The most difference observed in AEG0.5 fraction.

Mohammad Hojjatoleslamyi

2013-10-01

190

Granular rheology in zero gravity  

Energy Technology Data Exchange (ETDEWEB)

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.

Bossis, G [LPMC UMR 6622, Universite de Nice, Parc Valrose, 06108 Nice Cedex 2 (France); Grasselli, Y [EAI Tech CERAM, Rue A Einstein, BP 085, 06902 Sophia Antipolis Cedex (France); Volkova, O [LPMC UMR 6622, Universite de Nice, Parc Valrose, 06108 Nice Cedex 2 (France)

2004-05-12

191

Granular Rheology in Zero Gravity  

CERN Document Server

We present an experimental investigation on the rheological behavior 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 airplane undergoing parabolic flights to cancel the effect of gravity. In this configuration, the particles of the granular medium under flow can be compared to molecules of a dense gas. 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 behavior as a function of the solid volume fraction of particles exhibits a power law function. We observe at intermediate volume fraction, the formation of rings of particles regularly spaced along the height of the outer cylinder. The differences observed between experimental results and theoretical predictions are discussed and related to the structure formed in the granular medium submitt...

Bossis, G; Volkova, O

2003-01-01

192

Solid electrolyte electrochemical cell  

International Nuclear Information System (INIS)

A new type of electrochemical cell which can be used for generating electricity or in an electrolysis mode for producing gases such as hydrogen and oxygen comprises laterally spaced apart or side-by-side catalyst layers as electrodes with the gap between the catalyst layers being bridged by a solid electrolyte which provides an ion conductive path from one catalyst layer to the other. The catalyst layers and the electrolyte are preferably in the form of thin films or layers on the surface of an inert supporting substrate. A plurality of these cells may be disposed on the substrate and interconnected electrically forming a network of series and parallel connected cells. Means are provided to feed fuel and oxidant to the electrodes either as separate gases or mixed together if appropriate catalytic materials are selected

193

Solid-state graft copolymer electrolytes for lithium battery applications.  

Science.gov (United States)

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (< 80 °C), flammable, and volatile organic electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 °C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 °C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed. PMID:23963203

Hu, Qichao; Caputo, Antonio; Sadoway, Donald R

2013-01-01

194

Rheological properties of magnetorheological fluids  

Science.gov (United States)

The effects of dispersed phase saturation magnetization and applied magnetic fields on the rheological properties of magnetorheological (MR) fluids are described. MR fluids based on two different grades of carbonyl iron powder with different average particle size, 7-9 ?m (grade A) and 2 ?m (grade B), were prepared. Vibrating sample magnetometer measurements showed that the saturation magnetization values were 2.03 and 1.89 T for grades A and B, respectively. Rheological measurements were conducted for 33 and 40 vol% grade A and grade B based MR fluids with a specially built double Couette strain rate controlled rheometer at flux densities ranging from 0.2 to ~0.8 T. The yield stresses of 33 and 40 vol% grade A were 100 +/- 3 and 124 +/- 3 kPa, respectively at 0.8 +/- 0.1 T. The yield stress values of MR fluids based on finer particles (grade B) were consistently smaller. For example, the yield stresses for 33 and 40 vol% grade B based MR fluid were 80 +/- 8 and 102 +/- 2 kPa, respectively at 0.8 +/- 0.1 T. The yield stresses at the flux density approaching magnetic saturation in particles (B ~ 0.8T) were found to increase quadratically with the saturation magnetization (?0Ms) of the dispersed magnetic phase. This is in good agreement with the analytical models of uniformly saturated particle chains developed by Ginder and co-workers. The results presented here show that the decrease in yield stress for finer particle based MR fluids is due to the relatively smaller magnetization of the finer particles.

Genç, Seval; Phulé, Pradeep P.

2002-02-01

195

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 gn 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

196

Electrowetting with Electrolytes  

Science.gov (United States)

A theory of electrowetting is developed for systems containing an interface between two immiscible electrolytic solutions. Laws for the dependence of contact angle on electrode potential are presented. Ionic impermeability of the liquid-liquid interface and nonlinear double-layer responses rationalize observed phenomena such as contact-angle saturation and droplet contraction or detachment. The theoretical results can be applied to design new, precisely controllable microfluidic devices.

Monroe, Charles W.; Daikhin, Leonid I.; Urbakh, Michael; Kornyshev, Alexei A.

2006-09-01

197

Ice electrode electrolytic cell  

Science.gov (United States)

This invention relates to a method and apparatus for removing heavy metals from waste water, soils, or process streams by electrolytic cell means. The method includes cooling a cell cathode to form an ice layer over the cathode and then applying an electric current to deposit a layer of the heavy metal over the ice. The metal is then easily removed after melting the ice. In a second embodiment, the same ice-covered electrode can be employed to form powdered metals.

Glenn, David F. (Idaho Falls, ID); Suciu, Dan F. (Idaho Falls, ID); Harris, Taryl L. (Idaho Falls, ID); Ingram, Jani C. (Idaho Falls, ID)

1993-01-01

198

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

199

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

200

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

 
 
 
 
201

Lithium ion conducting electrolytes  

Science.gov (United States)

A liquid, predominantly lithium-conducting, ionic electrolyte having exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature, and comprising the lithium salts selected from the group consisting of the thiocyanate, iodide, bromide, chloride, perchlorate, acetate, tetrafluoroborate, perfluoromethane sulfonate, perfluoromethane sulfonamide, tetrahaloaluminate, and heptahaloaluminate salts of lithium, with or without a magnesium-salt selected from the group consisting of the perchlorate and acetate salts of magnesium. Certain of the latter embodiments may also contain molecular additives from the group of acetonitrile (CH.sub.3 CN) succinnonitrile (CH.sub.2 CN).sub.2, and tetraglyme (CH.sub.3 --O--CH.sub.2 --CH.sub.2 --O--).sub.2 (or like solvents) solvated to a Mg.sup.+2 cation to lower the freezing point of the electrolyte below room temperature. Other particularly useful embodiments contain up to about 40, but preferably not more than about 25, mol percent of a long chain polyether polymer dissolved in the lithium salts to provide an elastic or rubbery solid electrolyte of high ambient temperature conductivity and exceptional 100.degree. C. conductivity. Another embodiment contains up to about but not more than 10 mol percent of a molecular solvent such as acetone.

Angell, C. Austen (Tempe, AZ); Liu, Changle (Tempe, AZ)

1996-01-01

202

Electrolyte materials - Issues and challenges  

Science.gov (United States)

Electrolytes are vital components of an electrochemical energy storage device. They are usually composed of a solvent or mixture of solvents and a salt or a mixture of salts which provide the appropriate environment for ionic conduction. One of the main issues associated with the selection of a proper electrolyte is that its electronic properties have to be such that allow a wide electrochemical window - defined as the voltage range in which the electrolyte is not oxidized or reduced - suitable to the battery operating voltage. In addition, electrolytes must have high ionic conductivity and negligible electronic conductivity, be chemically stable with respect to the other battery components, have low flammability, and low cost. Weak stability of the electrolyte against oxidation or reduction leads to the formation of a solid-electrolyte interphase (SEI) layer at the surface of the cathode and anode respectively. Depending on the materials of the electrolyte and those of the electrode, the SEI layer may be composed by combinations of organic and inorganic species, and it may exert a passivating role. In this paper we discuss the current status of knowledge about electrolyte materials, including non-aqueous liquids, ionic liquids, solid ceramic and polymer electrolytes. We also review the basic knowledge about the SEI layer formation, and challenges for a rational design of stable electrolytes.

Balbuena, Perla B.

2014-06-01

203

Rheological Behavior of Schizophyllan in Fermentation System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 inde...

Singhal, Rekha S.; Kumar, Maushmi S.

2011-01-01

204

Rheological characterization of media containing Penicillium chrysogenum  

DEFF Research Database (Denmark)

Samples from fed-batch fermentations of Penicillium chrysogenum on complex medium are rheologically characterized. The behavior is well described by a power law model for which the parameters are estimates. Furthermore, two types of model media are characterized and compared with the real fermentation samples. Xanthan solutions are found to mimic the rheological properties of the filamentous fungi much better than carboxymethyl cellulose (CMC) solutions.

Pedersen, Annemarie Gade; Bundgaard-Nielsen, Mikael

1993-01-01

205

Rheological studies of concentrated guar gum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polymers and surfactants are essential ingredients of the printing paste. Polysaccharides are used commercially to thicken, suspend or stabilise aqueoussystems. Also they are used to produce gels and to act as flocculates, binders, lubricants, to serve as modifiers of film properties, and have a function as adjusters of rheological parameters. Surfactants, on the other hand, perform numerous functions acting as dispersants, wetting agents, emulsifiers and antifoaming agents. The rheological p...

Oblons?ek, Marija; S?ostar-turk, Sonja; Lapasin, Romano

2012-01-01

206

RHEOLOGY OF CHICKPEA PROTEIN CONCENTRATE DISPERSIONS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 stora...

Aurelia Ionescu; Iuliana Aprodu; Gabriela Gurau; Iuliana Banu

2011-01-01

207

Ultrasonic irradiation to modify the PEO/P(VDF-HFP)/TiO2 nanoparticle composite polymer electrolyte for dye sensitized solar cells  

International Nuclear Information System (INIS)

As a novel technology, ultrasonic irradiation was applied to modify the PEO/P(VDF-HFP)/TiO2 nanoparticle composite polymer electrolyte for dye sensitized solar cells (DSSCs). The ultrasonic irradiation effectively changes the rheology and the glass transition temperature and the crystallinity of the composite polymer. The experiments showed that 20 min moderate ultrasonic irradiation resulted in better penetration of the polymer electrolyte into the TiO2 nanoporous photo-anode, and the ionic conductivity was improved to 0.956 ms cm-1 compared with 0.386 ms cm-1 of the original polymer electrolyte. The DSSC fabricated with 20 min ultrasonic irradiation modified polymer electrolyte exhibited an improved solar energy conversion efficiency of 4.39% compared with the 3.6% of the unmodified polymer electrolyte DSSC at 30.2 mW cm-2 light intensity

208

Rheological properties of concentrated alumina slurries: influence of ph and dispersant agent  

International Nuclear Information System (INIS)

The relationship between the ph, the electrolyte concentrations and the rheological properties of high concentrated alumina slurries in aqueous medium is of great importance because it is considered to be the key to control the stability of the slurries from flocculation. Zeta potential of alumina slurries with and without Duramax C (dispersant agent) as a function of ph was studied. Two ph around the zero point of charge of alumina slurries were selected for the investigation of rheological properties. The rheological properties of aqueous alumina slurries with respect to different parameters, e.g.: viscosity, elastic modulus (storage modulus G) and viscous modulus (loss modulus G), were investigated. Viscosity measurements of the slurries as a function of Duramax C content at both ph 8.4 and 9.4) were used to determine the state of slurries. Three states of slurries, termed flocculated, partially de flocculated and fully de flocculated, were selected for further investigation. The viscosity of the three slurries at both ph as a function of shear rate was determined. Fully de flocculated slurry shows Newtonian behavior at all shear rates at both tested ph compared by the partial de flocculated and flocculated system. Results of investigation of G and G at ph of 9.4 as a function of applied stress explored the critical stress

209

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 gammaclim, 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

210

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

211

Magnetic rotational spectroscopy with nanorods to probe time-dependent rheology of microdroplets.  

Science.gov (United States)

In situ characterization of minute amounts of fluids that rapidly change their rheological properties is a challenge. In this paper, the rheological properties of fluids were evaluated by examining the behavior of magnetic nanorods in a rotating magnetic field. We proposed a theory describing the rotation of a magnetic nanorod in a fluid when its viscosity increases with time exponentially fast. To confirm the theory, we studied the time-dependent rheology of microdroplets of 2-hydroxyethyl-methacrylate (HEMA)/diethylene glycol dimethacylate (DEGDMA)-based hydrogel during photopolymerization synthesis. We demonstrated that magnetic rotational spectroscopy provides rich physicochemical information about the gelation process. The method allows one to completely specify the time-dependent viscosity by directly measuring characteristic viscosity and characteristic time. Remarkably, one can analyze not only the polymer solution, but also the suspension enriched with the gel domains being formed. Since the probing nanorods are measured in nanometers, this method can be used for the in vivo mapping of the rheological properties of biofluids and polymers on a microscopic level at short time intervals when other methods fall short. PMID:22668085

Tokarev, Alexander; Luzinov, Igor; Owens, Jeffery R; Kornev, Konstantin G

2012-07-01

212

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

Energy Technology Data Exchange (ETDEWEB)

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.

Lugao, Ademar B. E-mail: ablugao@net.ipen.br; Rogero, Sizue O.; Malmonge, S.M

2002-03-01

213

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

Science.gov (United States)

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.

Lugão, Ademar B.; Rogero, Sizue O.; Malmonge, Sônia M.

2002-03-01

214

Electrolytes for rechargeable lithium batteries  

Science.gov (United States)

Recent advances in the liquid electrolyte area for high-energy lithium 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 conductivity and differential scanning calorimetry results for polymer film electrolytes are presented. The advantages and the disadvantages of polymer thin-film electrolytes are discussed. It is apparent from these studies that films processed with a plasticizer such as PEGDME show improved conductivity, possibly due to increased amorphous phase content.

Venkatasetty, H. V.

215

Wormlike micelles in mixed amino acid surfactant/nonionic surfactant aqueous systems and the effect of added electrolytes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The formation of viscoelastic wormlike micelles in mixed amino acid surfactant/nonionic surfactant aqueous systems in the presence of different counterions and salts is reported, and the effects of the different electrolytes on the rheological behavior are discussed. N-dodecanoylglutamic acid (LAD) is neutralized with biologically relevant L-lysine and L-arginine to obtain anionic surfactants (LAD-Lys2, LAD-Arg2) which form aqueous micellar solutions at 25 degrees C. Addition of a nonionic su...

Shresta, Rekha Goswami; Rodriguez-abreu, Carlos; Aramaki, Kenji

2009-01-01

216

Electrolytic titanium production  

Energy Technology Data Exchange (ETDEWEB)

The Ginatta electrolytic plant was specifically designed and constructed for the production of titanium. Development stages that led to the construction of the electrowinning plant were reviewed. Electrochemical concepts and engineering criteria were outlined. Continuous steady state production of titanium crystals from the extraction compartments are obtained by supplying tetrachloride to the dissolution compartment. The cell electrodes are supplied with direct current from standard rectifiers. The equipment and the molten salt cells are operated by an aqueous tank house. The design is cost effective on an industrial scale because of significantly lower capital and operating costs. 13 refs., 5 figs.

Ginatta, M.; Berruti, R.; Orsello, G.; Semeraro, G.; Nidola, G. [GTT, Ginatta Torino Titanium (Italy)

1992-12-31

217

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

218

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

219

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

220

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

 
 
 
 
221

All-solid-state polymer electrolyte with plastic crystal materials for rechargeable lithium-ion battery  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we report the synthesis and properties of a series of composite polymer electrolytes formed by dispersion of a non-ionic organic plastic material succinonitrile (SN) into poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) complexed with four kinds of lithium salts. The addition of SN greatly enhances ionic conductivities of the electrolytes which is due to the high polarity and diffusivity of SN. The integrity of the plastic-crystalline phase is kept at low temperature range in polymer electrolytes. The high solubility of SN on Li salts is observed by Fourier transform infrared (FTIR) spectra measurement, thus could lead to enhanced lithium-ion transference number. The battery performances of composite polymer electrolytes at different temperatures are tested and the results are comparable to that of the pure plastic crystal electrolytes. (author)

Fan, Li-Zhen [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Wang, Xiao-Liang [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, 100084 Beijing (China); Long, Fei [Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, 541004 Guilin (China)

2009-04-01

222

Electrolytes - Technology review  

International Nuclear Information System (INIS)

Safety, lifetime, energy density, and costs are the key factors for battery development. This generates the need for improved cell chemistries and new, advanced battery materials. The components of an electrolyte are the solvent, in which a conducting salt and additives are dissolved. Each of them plays a specific role in the overall mechanism of a cell: the solvent provides the host medium for ionic conductivity, which originates in the conductive salt. Furthermore, additives can be used to optimize safety, performance, and cyclability. By understanding the tasks of the individual components and their optimum conditions of operation, the functionality of cells can be improved from a holistic point of view. This paper will present the most important technological features and requirements for electrolytes in lithium-ion batteries. The state-of-the-art chemistry of each component is presented, as well as different approaches for their modification. Finally, a comparison of Li-cells with lithium-based technologies currently under development is conducted

223

Gelled Electrolytes For Lithium Batteries  

Science.gov (United States)

Gelled polymer electrolyte consists of polyacrylonitrile (PAN), LiBF4, and propylene carbonate (PC). Thin films of electrolyte found to exhibit stable bulk conductivities of order of 10 to the negative 3rd power S/cm at room temperature. Used in thinfilm rechargeable lithium batteries having energy densities near 150 W h/kg.

Nagasubramanian, Ganesan; Attia, Alan; Halpert, Gerald

1993-01-01

224

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

225

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

226

Initial rheological description of high performance concretes  

Directory of Open Access Journals (Sweden)

Full Text Available 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 is 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

2006-12-01

227

Rheological porperties of simulated vitrification feeds  

International Nuclear Information System (INIS)

Radioactive waste will be immobilized in borosilicate glass at the Savannah River Site inside a remotely operated vitrification facility. In-process, on-line rheological measurements are preferred in a plant operating environment. Experiments were conducted to determine the rheological properties of a vitrification feed simulant to ensure compatibility with process equipment and determine the best data system for slurry characterization. Rheological feed properties were measured using a concentric cylinder rheometer and compared to theoretical models. Above shear rates of 200 sec-1, the appearance of the flow curves indicated inertial forces were significant and the analysis was hindered by variable gap sizes caused by particle deposition on the outer cylinder surface. Samples with varying weight percents of insoluble solids were analyzed to determine the variation in rheological properties with solids concentration. The consistency was found to be temperature dependent, but the yield stress was found to be relatively insensitive to temperatures between 25 and 50 C. These correlations were used to guide the operation of the dewatering process. The target solids concentration of the feed was set at 41 wt% insoluble solids to raise the yield stress of the slurry to about 100 dynes/cm2. This alleviated foaming of the material caused by entrainment of air within the processing equipment and the slurry was successfully vitrified. A combination of conccessfully vitrified. A combination of concentric cylinder rheometers and tube rheometers provides the best data system for characterizing the rheology of a vitrification slurry

228

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

229

Rheological properties of myosin-gelatin mixtures.  

Science.gov (United States)

This study was designed to investigate changes of dynamic rheological properties of myosin and gelatin mixtures during heating and cooling. The rheological and calorimetric attributes (G', G'', tan delta, and heat flow) of myosin and gelatin mixtures were measured during heating and cooling. The results indicated that gelatin could increase the G' and G'' values and decrease the denaturation temperature of myosin. The G' and G'' values of myosin and gelatin mixtures decreased with pH over 5.5 to 7.5 and ionic strength over 0.3 to 0.6. Therefore, it is advisable to add gelatin into chicken meat comminuted products in that it could improve the rheological attributes of myosin. PMID:17995714

Yang, Y L; Zhou, G H; Xu, X L; Wang, Y

2007-06-01

230

Rheological characteristics of Saudi crude oil emulsions  

Energy Technology Data Exchange (ETDEWEB)

Rheological characteristics of saudi crude oil emulsions were measured with a Brookfield viscometer at temperatures of 10, 20, 30 and 40C. The Saudi field crude oils used in the present study were: heavy, medium, light and extralight. The emulsion constituents were crude oil, brine, emulsifier (Triton X-100) and dilute hydrochloric acid. The measured data were first classified into two groups for Newtonian and non-Newtonian fluids. The results showed that the non-Newtonian emulsions exhibit pseudoplastic behavior and their rheological characteristics can be described by the power-law model. Then, the effect of dispersed phase (oil) concentration and temperature on the rheological behavior of the emulsions were thoroughly investigated using statistical analysis (t-test). 16 figs., 5 tabs., 13 refs.

Omar, A.E.; Desouky, S.M.; Karama, B. (King Saud Univ., Riyadh (Saudi Arabia))

1991-09-01

231

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

232

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

233

Crosslinkable fumed silica-based nanocomposite electrolytes for rechargeable lithium batteries  

Energy Technology Data Exchange (ETDEWEB)

Electrochemical and rheological properties are reported of composite polymer electrolytes (CPEs) consisting of dual-functionalized fumed silica with methacrylate and octyl groups+low-molecular weight poly(ethylene glycol) dimethyl ether (PEGdm)+lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, lithium imide)+butyl methacrylate (BMA). The role of butyl methacrylate, which aids in formation of a crosslinked network by tethering adjacent fumed silica particles, on rheology and electrochemistry is examined together with the effects of fumed silica surface group, fumed silica weight percent, salt concentration, and solvent molecular weight. Chemical crosslinking of the fumed silica with 20% BMA shows a substantial increase in the elastic modulus of the system and a transition from a liquid-like/flocculated state to an elastic network. In contrast, no change in lithium transference number and only a modest decrease (factor of 2) on conductivity of the CPE are observed, indicating that a crosslinked silica network has minimal effect on the mechanism of ionic transport. These trends suggest that the chemical crosslinks occur on a microscopic scale, as opposed to a molecular scale, between adjacent silica particles and therefore do not impede the segmental mobility of the PEGdm. The relative proportion of the methacrylate and octyl groups on the silica surface displays a nominal effect on both rheology and conductivity following crosslinking although the pre-cure rheology is a function of the surface groups. Chemical crosslinked nanocomposite polymer electrolytes offer significant higher elastic modulus and yield stress than the physical nanocomposite counterpart with a small/negligible penalty of transport properties. The crosslinked CPEs exhibit good interfacial stability with lithium metal at open circuit, however, they perform poorly in cycling of lithium-lithium cells. (author)

Li, Yangxing; Yerian, Jeffrey A.; Khan, Saad A.; Fedkiw, Peter S. [Department of Chemical & amp; Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905 (United States)

2006-10-27

234

Rheology of interfacial protein-polysaccharide composites  

Science.gov (United States)

The morphology and mechanical properties of protein adsorption layers can significantly be altered by the presence of surfactants, lipids, particles, other proteins, and polysaccharides. In food emulsions, polysaccharides are primarily considered as bulk thickener but can under appropriate environmental conditions stabilize or destabilize the protein adsorption layer and, thus, the entire emulsion system. Despite their ubiquitous usage as stabilization agent, relatively few investigations focus on the interfacial rheology of composite protein/polysaccharide adsorption layers. The manuscript provides a brief review on both main stabilization mechanisms, thermodynamic phase separation and electrostatic interaction and discusses the rheological response in light of the environmental conditions such as ionic strength and pH.

Fischer, P.

2013-05-01

235

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

236

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

237

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

238

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.degree. 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.

Angell, C. Austen (Mesa, AZ); Xu, Kang (Tempe, AZ); Liu, Changle (Tulsa, OK)

1996-01-01

239

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

240

Electrolytic production of uranium alloy in molten salt electrolyte  

International Nuclear Information System (INIS)

Uranium alloy is produced in an electrolytic cell from a molten salt electrolyte by adding an alloying component eg.rod to the uranium produced in the cell. The addition of the alloying component can take place inside the cell, or to uranium withdrawn from the cell and subsequently returned to the cell. The alloying component may also be liquid, granules. Addition of the alloying component enables reduction in the operating temperature of the cell. (author)

 
 
 
 
241

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

242

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

243

Effects of swimming on erythrocyte rheological properties  

Directory of Open Access Journals (Sweden)

Full Text Available Exercise and lactate usually change blood rheology but, effect of swimming on blood rheology is not clear. Blood lactate concentration increases after 400-meter freestyle swimming. In the hemorheological studies, determination of the erythrocyte deformability and aggregation facilitates the evaluation of rheological behaviours of the erythrocytes. The present study was performed to investigate the effects of acute swimming exercise on erythrocyte deformability and aggregation. Seventeen male university swimmers participated in the study. For 400-meter freestyle swimming, participants were asked to swim as fast as they could. Blood lactate concentration, erythrocyte lipid peroxidation and plasma protein oxidation levels, erythrocyte deformability and aggregation, and several haematological parameters were investigated after swimming and they were compared with pre-exercise values. Erythrocyte lipid peroxidation and plasma protein oxidation were unchanged with swimming. Blood lactate concentration increased after 400-meter swimming (p<0.001. Erythrocyte aggregation increased after acute swimming (p<0.01 while erythrocyte deformability was not change. There were no correlations between blood lactate and erythrocyte hemorheological properties before and after swimming.In conclusion, we found that erythrocyte aggregation increased after acute swimming. Further studies are needed to reveal the late effects of acute swimming and to elucidate the effect of swimming different distances on erythrocyte rheological properties.

AE Ustuntas

2010-06-01

244

Morphology and rheology in filamentous cultivations.  

Science.gov (United States)

Because of their metabolic diversity, high production capacity, secretion efficiency, and capability of carrying out posttranslational modifications, filamentous fungi are widely exploited as efficient cell factories in the production of metabolites, bioactive substances, and native or heterologous proteins, respectively. There is, however, a complex relationship between the morphology of these microorganisms, transport phenomena, the viscosity of the cultivation broth, and related productivity. The morphological characteristics vary between freely dispersed mycelia and distinct pellets of aggregated biomass, every growth form having a distinct influence on broth rheology. Hence, the advantages and disadvantages for mycelial or pellet cultivation have to be balanced out carefully. Because of the still inadequate understanding of the morphogenesis of filamentous microorganisms, fungal morphology is often a bottleneck of productivity in industrial production. To obtain an optimized production process, it is of great importance to gain a better understanding of the molecular and cell biology of these microorganisms as well as the relevant approaches in biochemical engineering. In this chapter, morphology and growth of filamentous fungi are described, with special attention given to specific problems as they arise from fungal growth forms; growth and mass transfer in fungal biopellets are discussed as an example. To emphasize the importance of the flow behavior of filamentous cultivation broths, an introduction to rheology is also given, reviewing important rheological models and recent studies concerning rheological parameters. Furthermore, current knowledge on morphology and productivity in relation to the environom is outlined in the last section of this review. PMID:20602989

Wucherpfennig, T; Kiep, K A; Driouch, H; Wittmann, C; Krull, R

2010-01-01

245

Non-Newtonian Rheology in Blood Circulation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Blood is a complex suspension that demonstrates several non-Newtonian rheological characteristics such as deformation-rate dependency, viscoelasticity and yield stress. In this paper we outline some issues related to the non-Newtonian effects in blood circulation system and present modeling approaches based mostly on the past work in this field.

Sochi, Taha

2013-01-01

246

NEW RHEOLOGICAL MODELS FOR MINERAL OIL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2013-01-01

247

Study of the rheology and dynamics in micellar triblock copolymers and the shear thickening of CTA-n-Fluorobenzoate systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis aims to understand the effect of the dynamics of copolymer micelles on their rheological properties. Indeed amphiphilic copolymers can self-assemble in water to form various micellar microstructures spherical, cylindrical or lamellar. Their dynamic is a critical parameter to define their range of applications, particularly in the transport of drugs and in the synthesis of mesostructured materials. Micelles are structured continuous: they can form and dissociate into monomers, merg...

Landazuri Gomez, Gabriel

2013-01-01

248

Polypropylene/Mg3Al-tartrazine LDH nanocomposites with enhanced thermal stability, UV absorption, and rheological properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report the synthesis of coloured polypropylene (PP)/Mg 3Al-tartrazine layered double hydroxide (LDH) nanocomposites with enhanced thermal stability, UV absorption capacity, and rheological properties using a modified solvent mixing method for the first time. SEM images indicated that the LDH nanoparticles were evenly dispersed within the PP matrix due to the favourable interactions between PP and LDHs. TGA and DSC analysis indicated that the thermal stability of PP/LDH nanocomposites was s...

Wang, Q.; Wu, J.; Gao, Y.; Zhang, Z.; Wang, J.; Zhang, X.; Yan, X.; Umar, A.; Guo, Z.; O Hare, D.

2013-01-01

249

Plasma spray synthesis of La{sub 10}(SiO{sub 4}){sub 6}O{sub 3} as a new electrolyte for intermediate temperature solid oxide fuel cells  

Energy Technology Data Exchange (ETDEWEB)

The apatite-type lanthanum silicate films were successfully synthesized by modified atmosphere plasma spraying using lanthanum oxide and silicon oxide mixed powders and precalcined hypereutectic powders in the size range 1-3 {mu}m and 5-8 {mu}m, respectively, as starting feedstock materials. The films differed not only in microstructural scale, but also in the characteristic of the degree of film densification. A detail describing the evolution of microstructure has been discussed. A considerable improvement in densification of the La{sub 10}(SiO{sub 4}){sub 6}O{sub 3} electrolyte films has been observed. (author)

Gao, Wei [LERMPS, University of Technology of Belfort-Montbeliard, Belfort 90010 (France); National Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Liao, Han-Lin; Coddet, Christian [LERMPS, University of Technology of Belfort-Montbeliard, Belfort 90010 (France)

2008-05-01

250

Electrolytes for lithium ion batteries  

Science.gov (United States)

A family of electrolytes for use in a lithium ion battery. The genus of electrolytes includes ketone-based solvents, such as, 2,4-dimethyl-3-pentanone; 3,3-dimethyl 2-butanone(pinacolone) and 2-butanone. These solvents can be used in combination with non-Lewis Acid salts, such as Li.sub.2[B.sub.12F.sub.12] and LiBOB.

Vaughey, John; Jansen, Andrew N.; Dees, Dennis W.

2014-08-05

251

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

252

Electrode, current collector, and electrolyte studies for AMTEC cells  

International Nuclear Information System (INIS)

Studies of components for AMTEC devices at JPL have focussed on electrode materials, materials and construction of the current collection network, and the ? double-prime-alumina solid electrolyte. Electrode materials include thin films of molybdenum metal and metal alloys such as PtW and RhW. Surface self-diffusion coefficients have been determined for Mo electrodes in the temperature range 1050--1200 K, and for RhW at 1125 K. The diffusion coefficients have been used in a grain growth model to predict electrode operating lifetimes at temperatures in this range. Current collection networks sputtered with a thin film of platinum have decreased total electrical resistance in an operating device by 35%. Electrolyte studies have found no mechanical stress or chemical degradation induced by long term operation. Further electrolyte studies have focussed on synthesis of both sodium and potassium ? double-prime-alumina ceramic. Potassium ? double-prime-alumina solid electrolyte has potential application in a potassium-based AMTEC device which operates at a hot side temperature of ?1000 K

253

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

254

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

255

Influence of the type of electrolyte on the morphological and crystallographic characteristics of lead powder particles  

Directory of Open Access Journals (Sweden)

Full Text Available Lead electrodeposition processes from the basic (nitrate and complex (acetate electrolytes were mutually compared by the scanning electron microscopic and the X-ray diffraction analysis of the produced powder particles. The shape of dendritic particles strongly depended on the type of electrolyte. The dendrites composed of stalk and weakly developed primary branches (the primary type were predominantly formed from the basic electrolyte. The ramified dendrites composed of stalk and of both primary and secondary branches (the secondary type were mainly formed from the complex electrolyte. In the both type of powder particles Pb crystallites were predominantly oriented in the (111 plane. Formation of powder particles of the different shape with the strong (111 preferred orientation was discussed and explained by the consideration of the general characteristics of the growth of a crystal in the electrocrystallization processes. [Projekat Ministarstva nauke Republike Srbije, br. 172046: Electrochemical synthesis and characterization of nanostructured functional materials for application in new technologies

Nikoli? Nebojša D.

2013-01-01

256

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

257

Hybrid proton-conducting membranes for polymer electrolyte fuel cells  

International Nuclear Information System (INIS)

The synthesis and characterization of a novel hybrid organic-inorganic material formed by phosphomolybdic acid H3PMo12O40 (PMo12) and poly(2,5-benzimidazole) (ABPBI) is reported. This material, composed of two proton-conducting components, can be cast in the form of membranes from methanesulfonic acid (MSA) solutions. Upon impregnation with phosphoric acid, the hybrid membranes present higher conductivity than the best ABPBI polymer membranes impregnated in the same conditions. These electrolyte membranes are stable up to 200 deg. C, and have a proton conductivity of 3 x 10-2 S cm-1 at 185 deg. C without humidification. These properties make them very good candidates as membranes for polymer electrolyte membrane fuel cells (PEMFC) at temperatures of 100-200 deg. C

258

Hybrid proton-conducting membranes for polymer electrolyte fuel cells  

Energy Technology Data Exchange (ETDEWEB)

The synthesis and characterization of a novel hybrid organic-inorganic material formed by phosphomolybdic acid H{sub 3}PMo{sub 12}O{sub 40} (PMo{sub 12}) and poly(2,5-benzimidazole) (ABPBI) is reported. This material, composed of two proton-conducting components, can be cast in the form of membranes from methanesulfonic acid (MSA) solutions. Upon impregnation with phosphoric acid, the hybrid membranes present higher conductivity than the best ABPBI polymer membranes impregnated in the same conditions. These electrolyte membranes are stable up to 200 deg. C, and have a proton conductivity of 3 x 10{sup -2} S cm{sup -1} at 185 deg. C without humidification. These properties make them very good candidates as membranes for polymer electrolyte membrane fuel cells (PEMFC) at temperatures of 100-200 deg. C.

Gomez-Romero, Pedro [Institut de Ciencia de Materials de Barcelona (CSIC), Campus UAB, E-08193 Bellaterra (Barcelona) (Spain)]. E-mail: pedro.gomez@icmab.es; Asensio, Juan Antonio [Institut de Ciencia de Materials de Barcelona (CSIC), Campus UAB, E-08193 Bellaterra (Barcelona) (Spain); Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta 390, E-08017 Barcelona (Spain); Borros, Salvador [Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta 390, E-08017 Barcelona (Spain)

2005-08-30

259

Analytical rheology of metallocene-catalyzed polyethylenes  

Science.gov (United States)

A computational algorithm that seeks to invert the linear viscoelastic spectrum of single-site metallocene-catalyzed polyethylenes is presented. The algorithm uses a general linear rheological model of branched polymers as its underlying engine, and is based on a Bayesian formulation that transforms the inverse problem into a sampling problem. Given experimental rheological data on unknown single-site metallocene- catalyzed polyethylenes, it is able to quantitatively describe the range of values of weight-averaged molecular molecular weight, MW, and average branching density, bm, consistent with the data. The algorithm uses a Markov-chain Monte Carlo method to simulate the sampling problem. If, and when information about the molecular weight is available through supplementary experiments, such as chromatography or light scattering, it can easily be incorporated into the algorithm, as demonstrated.

Shanbhag, Sachin; Takeh, Arsia

2011-03-01

260

Experimental droplet dynamics and interfacial rheology characterization  

Science.gov (United States)

Many properties of emulsions arise from interfacial rheology. Recently, a theory of droplet dynamics accounting for interfacial rheology, Marangoni forces and mass transport was developed. Here, we describe experimental observations of droplet dynamics in light of this theory. Using particle tracking velocimetry, we examine the dynamics of surfactant-stabilized droplets in the Poiseuille flow of a microfluidic device. Interfacial shear and dilatational properties are evaluated, and we distinguish viscous and elastic effects. We find that the shear viscosity of the interface populated by block copolymer surfactant is greater than with small molecule alcohol surfactant. Investigation of small droplets is of interest not only for their relevance to emulsion applications, but their small size has potential for improved force sensitivity and temporal resolution. Other droplet dynamic approaches will be discussed.

Erk, Kendra; Martin, Jeffrey; Schwalbe, Jonathan; Phelan, Frederick, Jr.; Hudson, Steven

2011-11-01

 
 
 
 
261

On transient rheology and glacial isostasy  

Science.gov (United States)

The effect of transient creep on the inference of long-term mantle viscosity is investigated using theoretical predictions from self-gravitating, layered earth models with Maxwell, Burgers' body, and standard linear solid rheologies. The interaction between transient and steady-state rheologies is studied. The responses of the standard linear solid and Burgers' body models to transient creep in the entire mantle, and of the Burgers' body and Maxwell models to creep in the lower mantle are described. The models' responses are examined in terms of the surface displacement, free air gravity anomaly, wander of the rotation pole, and the secular variation of the degree 2 zonal coefficient of the earth's gravitational potential field. The data reveal that transient creep cannot operate throughout the entire mantle.

Yuen, David A.; Sabadini, Roberto C. A.; Gasperini, Paolo; Boschi, Enzo

1986-01-01

262

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

263

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

264

RHEOLOGICAL BEHAVIOR STUDY OF HIDRAULIC OIL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheological behavior of this article presents hydraulic oil. Dynamic viscosity of hydraulic oil was determined at temperatures between 400C -900C and shear rates ranging from 3.3-120s^-1. Temperature of hydraulic oil at 313K has a Bingham fluid behavior with correlation coefficient value close to one. Between 323 and 333K temperature behavior of oil has a Casson fluid and the temperature range 343 to363K oil and behaves like an Ostwald-de Waele fluid.

IOANA STANCIU

2012-01-01

265

Rheological evaluation of pretreated cladding removal waste  

International Nuclear Information System (INIS)

Cladding removal waste (CRW) contains concentrations of transuranic (TRU) elements in the 80 to 350 nCi/g range. This waste will require pretreatment before it can be disposed of as glass or grout at Hanford. The CRW will be pretreated with a rare earth strike and solids removal by centrifugation to segregate the TRU fraction from the non-TRU fraction of the waste. The centrifuge centrate will be neutralized with sodium hydroxide. This neutralized cladding removal waste (NCRW) is expected to be suitable for grouting. The TRU solids removed by centrifugation will be vitrified. The goal of the Rheological Evaluation of Pretreated Cladding Removal Waste Program was to evaluate those rheological and transport properties critical to assuring successful handling of the NCRW and TRU solids streams and to demonstrate transfers in a semi-prototypic pumping environment. This goal was achieved by a combination of laboratory and pilot-scale evaluations. The results obtained during these evaluations were correlated with classical rheological models and scaled-up to predict the performance that is likely to occur in the full-scale system. The Program used simulated NCRW and TRU solid slurries. Rockwell Hanford Operations (Rockwell) provided 150 gallons of simulated CRW and 5 gallons of simulated TRU solid slurry. The simulated CRW was neutralized by Pacific Northwest Laboratory (PNL). The physical and rheological properties of the NCRW and TRU solid slurries were evaluated in the laboratory. The properties displayed by NCRW allowed it to be classified as a pseudoplastic or yield-pseudoplastic non-Newtonian fluid. The TRU solids slurry contained very few solids. This slurry exhibited the properties associated with a pseudoplastic non-Newtonian fluid

266

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

267

Rheological properties of alumina injection feedstocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2005-01-01

268

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

269

Rheological studies of tautomerization kinetics in supercooled glibenclamide drug  

Science.gov (United States)

Rheological measurements have been applied to study the tautomerization of the pharmaceutically active compound glibenclamide. The rate constant and activation energy of the imidic-acid-amide transformation have been successfully determined by monitoring the evolution of shear viscosity. The kinetic parameters from rheological measurements agree reasonably well with the data previously obtained from dielectric spectroscopy. The present Brief Report demonstrates that rheology can provide a fast and precise way to characterize the reaction kinetics of tautomerization.

Wojnarowska, Z.; Wang, Y.; Sokolov, A. P.; Paluch, M.

2012-12-01

270

Rheological performance of cementitious materials used in well cementing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

PAPER 8: Hodne, H., Saasen, A. and Pita, E., "Rheology of cementitious suspensionscontaining weighting agents", Annual Transactions The Nordic RheologySociety, 13, 191-197, (2005) - http://www.sik.se/nrs/Open_transactions/2005/Rheology%20of%20cementitious%20suspensions%20containing%20weighting%20agents%20H.%20Hodne,%20A.%20Saasen%20and%20E.%20Pita.pdf

Hodne, Helge

2007-01-01

271

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

272

Decontamination process through electrolytic reduction  

International Nuclear Information System (INIS)

Purpose: To improve the decontamination efficiency by increasing solubility of radioactive oxide layers. Method: Materials to be decontaminated are subjected to electrolytic reducing decontamination while connecting metal materials deposited with radioactive elements, an electrolytic cell and the negative electrode of a power source. The electrolytic cell is separated into two cells, that is, a cathode chamber and an anode chamber. A cationic exchange membrane is disposed between the cells and a cathode electrode and an anode electrode are disposed respectively to each of the cells. Substances leached out upon decontamination are eliminated by through a filterating desalter. Such a decontaminating process can remove oxide layers containing radioactive elements on the surface of equipments and pipeways, as well as suppress the dose rate at the surface thereof in the primary cooling circuit of a nuclear power plant. (Moriyama, K.)

273

High elastic modulus polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

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

274

Rheological properties of a vesicle suspension  

Science.gov (United States)

The rheological behavior of a dilute suspension of vesicles in linear shear flow at a finite concentration is analytically examined. In the quasispherical limit, two coupled nonlinear equations that describe the vesicle orientation in the flow and its shape evolution were derived [Phys. Rev. Lett. 96, 028104 (2006), 10.1103/PhysRevLett.96.028104] and serve here as a starting point. Of special interest is to provide, for the first time, an exact analytical prediction of the time-dependent effective viscosity ?eff and normal stress differences N1 and N2. Our results shed light on the effect of the viscosity ratio ? (defined as the inner over the outer fluid viscosities) as the main controlling parameter. It is shown that ?eff,N1 , and N2 either tend to a steady state or describe a periodic time-dependent rheological response, previously reported numerically and experimentally. In particular, the shear viscosity minimum and the cusp singularities of ?eff,N1 , and N2 at the tumbling threshold are brought to light. We also report on rheology properties for an arbitrary linear flow. We were able to obtain a constitutive law in a closed form relating the stress tensor to the strain rate tensor. It is found that the resulting constitutive markedly contrasts with classical laws known for other complex fluids, such as emulsions, capsule suspensions, and dilute polymer solutions (Oldroyd B model). We highlight the main differences between our law and classical laws.

Guedda, M.; Benlahsen, M.; Misbah, C.

2014-11-01

275

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

276

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

277

Superionic solids and solid electrolytes  

International Nuclear Information System (INIS)

Superionic solids and solid electrolytes are a special group of materials showing high ionic conductivity with tremendous technological potential. This book updates the present status of the field. Starting with an overview of recent trends in solid state ionics, the book ends with the assessment of future implications. Different theoretical, experimental (including NMR), and materials aspects have been covered along with applications. Important materials covered include alkali and silver ion conductors, fluorites, Nasicon, heterogeneous solid electrolytes, and glasses. The theoretical topics covered in this volume include phenomenological models, fractal techniques, the pre-exponential problem, and fluctuations

278

Superionic solids and solid electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Superionic solids and solid electrolytes are a special group of materials showing high ionic conductivity with tremendous technological potential. This book updates the present status of the field. Starting with an overview of recent trends in solid state ionics, the book ends with the assessment of future implications. Different theoretical, experimental (including NMR), and materials aspects have been covered along with applications. Important materials covered include alkali and silver ion conductors, fluorites, Nasicon, heterogeneous solid electrolytes, and glasses. The theoretical topics covered in this volume include phenomenological models, fractal techniques, the pre-exponential problem, and fluctuations.

Laskar, A. (Clemson Univ., SC (US)); Chandra, S. (Banaras Hindu Univ., Varanasi (IN))

1989-01-01

279

Electrolytic indium refining from cadmium in glycerine electrolyte  

International Nuclear Information System (INIS)

The results of investigations directed on development of electrochemical indium cleaning from cadmium in glycerine base electrolyte are presented. Optimal operational conditions, specific consumption of reactants and electric power are determined. Relationship between variation of concentration of cadmium impurity in refined metal and duration of electrolysis is revealed. The method for determination of cleaning time is proposed. Developed process was put into commercial operation

280

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

 
 
 
 
281

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

282

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

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

Development of Alternative Rheological Measurements for DWPF Slurry Samples  

International Nuclear Information System (INIS)

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 toof 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

285

Ionic conductivity of solid electrolytes  

International Nuclear Information System (INIS)

It is defined, that in the solid electrolytes the conductivity is determines by both liquid and jump mechanisms. In the ionic conductors of NASICON-type it is possible realization of superionic conductivity due to mainly by the liquid mechanism of conductivity. (author)

286

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

287

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

288

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

289

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

290

Rheological complexity in simple chain models.  

Science.gov (United States)

Dynamical properties of short freely jointed and freely rotating chains are studied using molecular dynamics simulations. These results are combined with those of previous studies, and the degree of rheological complexity of the two models is assessed. New results are based on an improved analysis procedure of the rotational relaxation of the second Legendre polynomials of the end-to-end vector in terms of the Kohlrausch-Williams-Watts (KWW) function. Increased accuracy permits the variation of the KWW stretching exponent beta to be tracked over a wide range of state points. The smoothness of beta as a function of packing fraction eta is a testimony both to the accuracy of the analytical methods and the appropriateness of (eta(0)-eta) as a measure of the distance to the ideal glass transition at eta(0). Relatively direct comparison is made with experiment by viewing beta as a function of the KWW relaxation time tau(KWW). The simulation results are found to be typical of small molecular glass formers. Several manifestations of rheological complexity are considered. First, the proportionality of alpha-relaxation times is explored by the comparison of translational to rotational motion (i.e., the Debye-Stokes-Einstein relation), of motion on different length scales (i.e., the Stokes-Einstein relation), and of rotational motion at intermediate times to that at long time. Second, the range of time-temperature superposition master curve behavior is assessed. Third, the variation of beta across state points is tracked. Although no particulate model of a liquid is rigorously rheologically simple, we find freely jointed chains closely approximated this idealization, while freely rotating chains display distinctly complex dynamical features. PMID:18532846

Dotson, Taylor C; Heffernan, Julieanne V; Budzien, Joanne; Dotson, Keenan T; Avila, Francisco; Limmer, David T; McCoy, Daniel T; McCoy, John D; Adolf, Douglas B

2008-05-14

291

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.)

292

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

293

Measurements of rheological and structural properties of lubricant films  

Science.gov (United States)

Understanding the rheological and structural properties of long-chain molecules presents fundamental challenges and yet is of immense technological importance. Most common, experimental techniques available for studying the rheological and structural properties are cone-plate and Couette geometries. However, these techniques are limited to moderate shear rate because of the difficulty in removing the viscous heat. A high shear rate home-built parallel-plate rotational rheometer has been used for measurements of rheological and structural properties. The design is similar to a hard disk drive; a thin film is sheared between optically transparent disc and slider. While the rheological properties of the polymer thin film can be obtained from the stresses on the slider, small-angel light scattering and other optical techniques can investigate the sample structure. The film thickness is monitored using a capacitive method. Perfluoropolyether lubricant films were used to test the apparatus and investigate the rheological and structural properties of the films.

Mriziq, Khaled S.; Dai, Horn-Ji; Dadmun, Mark D.; Cochran, Hank D.

2002-03-01

294

Interfacial shear rheology of protein-surfactant layers.  

Science.gov (United States)

The shear rheology of adsorbed or spread layers at air/liquid and liquid/liquid phase boundaries is relevant in a wide range of technical applications such as mass transfer, monolayers, foaming, emulsification, oil recovery, or high speed coating. Interfacial shear rheological properties can provide important information about interactions and molecular structure in the interfacial layer. A variety of measuring techniques have been proposed in the literature to measure interfacial shear rheological properties and have been applied to pure protein or mixed protein adsorption layers at air/water or oil/water interfaces. Such systems play for example an important role as stabilizers in foams and emulsions. The aim of this contribution is to give a literature overview of interfacial shear rheological studies of pure protein and protein/surfactant mixtures at liquid interfaces measured with different techniques. Techniques which utilize the damping of waves, spectroscopic or AFM techniques and all micro-rheological techniques will not discuss here. PMID:18823871

Krägel, J; Derkatch, S R; Miller, R

2008-12-01

295

New trivalent imidazole-derived salt for lithium-ion cell electrolyte  

Science.gov (United States)

Lithium-ion cells utilize almost exclusively monovalent lithium salts as main electrolyte component. Apart from scarce works on sulfonyl imide derivatives, even in terms of basic parameters little is known about multivalent lithium salts' behavior in electrolytes. Here we present the new trivalent lithium salt dedicated to electrolytes for lithium-ion cells. Trilithium 2,2?,2?-tris(trifluoromethyl)benzotris(imidazolate) (Li3BTI) synthesis and its performance in PC and EC:DMC solutions is described in this paper. The structure and stability of this new lithium salt was fully characterized by NMR and Raman techniques as well as thermal methods. Basic electrochemical parameters of electrolytes based on this salt were done by linear sweep voltammetry, lithium cation transference number and conductivity measurements. The salt was designed specifically to manifest extraordinarily high lithium cation transference number (0.73 in EC:DMC 1:1 ratio mixture). However this new salt exhibits also thermal stability of 160 °C and electrochemical stability up to 4.5 V vs Li, as well as conductivities of the 1 mS cm-1 order of magnitude in liquid electrolytes. Promising compatibility results of the obtained electrolyte against Si/C composite anodes are also reported in this paper.

Trzeciak, Tomasz; Niedzicki, Leszek; Groszek, Grazyna; Wieczorek, Piotr; Marcinek, Marek; Wieczorek, Wladyslaw

2014-04-01

296

Effect of a novel amphipathic ionic liquid on lithium deposition in gel polymer electrolytes  

International Nuclear Information System (INIS)

Highlights: · Synthesis of a dimeric ionic liquid. · Gel polymer electrolytes providing uniform lithium deposit pathway. · An amphipathic ionic liquid locates at the interface between an electrolyte-rich phase and a polymer matrix in a gel polymer electrolyte. · The presence of PDMITFSI ionic liquid leads to the suppression of dendritic lithium formation on a lithium metal electrode. - Abstract: A novel dimeric ionic liquid based on imidazolium cation and bis(trifluoromethanesulfonyl) imide (TFSI) anion has been synthesized through a metathesis reaction. Its chemical shift values and thermal properties are identified via 1H nuclear magnetic resonance (NMR) imaging and differential scanning calorimetry (DSC). The effect of the synthesized dimeric ionic liquid on the interfacial resistance of gel polymer electrolytes is described. Differences in the SEM images of lithium electrodes after lithium deposition with and without the 1,1'-pentyl-bis(2,3-dimethylimidazolium) bis(trifluoromethane-sulfonyl)imide (PDMITFSI) ionic liquid in gel polymer electrolytes are clearly discernible. This occurs because the PDMITFSI ionic liquid with hydrophobic moieties and polar groups modulates lithium deposit pathways onto the lithium metal anode. Moreover, high anodic stability for a gel polymer electrolyte with the PDMITFSI ionic liquid was clearly observed.

297

RHEOLOGICAL BEHAVIOR STUDY OF HIDRAULIC OIL  

Directory of Open Access Journals (Sweden)

Full Text Available Rheological behavior of this article presents hydraulic oil. Dynamic viscosity of hydraulic oil was determined at temperatures between 400C -900C and shear rates ranging from 3.3-120s^-1. Temperature of hydraulic oil at 313K has a Bingham fluid behavior with correlation coefficient value close to one. Between 323 and 333K temperature behavior of oil has a Casson fluid and the temperature range 343 to363K oil and behaves like an Ostwald-de Waele fluid.

IOANA STANCIU

2012-03-01

298

Hydrodynamics and Rheology of Active Liquid Crystals  

Science.gov (United States)

Active liquid crystals such as swimming bacteria, active gels and assemblies of motors and filaments are active complex fluids. Such systems differ from their passive counterparts in that particles absorb energy and generate motion. They are interesting from a more fundamental perspective as their dynamic phenomenons are both physically fascinating and potentially of great biological significance. In this talk, I will present a continuum model for active liquid crystals and analyze the behavior of a suspension subjected to a weak Poiseuille flow. Hydrodynamics, stability and rheology will also be discussed.

Cui, Zhenlu

2012-02-01

299

Rheological Characterization of Shale – Mud Interactions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Emofurieta, W. O.; Odeh, A. O.

2012-01-01

300

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

 
 
 
 
301

Vertically Integrated Rheology of Deforming Oceanic Lithosphere  

Science.gov (United States)

The tectonics of the oceans have traditionally been modeled in terms of rigid plates interacting at narrow boundaries. The now well-documented existence of diffuse oceanic plate boundaries, across which relative motion is distributed over hundreds to thousands of kilometers, demonstrates the need for a different approach to understanding the tectonics and geodynamics of a substantial fraction of oceanic lithosphere. A model that has usefully been applied to diffuse zones of continental deformation is that of a thin viscous sheet of fluid obeying a power-law rheology. The model has few adjustable parameters, typically a power-law exponent, n, and the Argand number [England & McKenzie, 1982], which is a measure of the size of buoyancy forces caused by the deformation, and which can be neglected for deformation of oceanic lithosphere. In prior investigations of a thin sheet of power-law fluid for continental regions, most studies have found that the most appropriate power-law exponent is ?3 [e.g., England & Molnar 1991, 1997], but a value as large as ?10 has been recently suggested by Dayem et al. [2009]. Because the rheology of oceanic lithosphere differs significantly from that of continental lithosphere, the most appropriate exponent may be larger than 3, and should in some sense be an appropriately weighted average between the properties of the upper lithosphere, which deforms brittlely and semi-brittlely, and for which the power-law exponent is n ? ?, and the lower lithosphere, which deforms by dislocation glide [Goetze 1978; Evans & Goetze 1979; Ratteron et al. 2003; Dayem et al. 2009; Mei et al. 2010], which obeys an exponential law, and by dislocation creep for which n?3 [Sonder & England, 1986]. To estimate the appropriate power-law exponent consistent with laboratory experiments we determine strain rate as a function of applied end load on the lithosphere for various ages of lithosphere. We find that a power-law fluid well approximates the vertically integrated rheology of oceanic lithosphere determined from laboratory experiments and that the best-fitting power-law exponent for the vertically integrated rheology is insensitive to strain rate. We also find that, except for very young lithosphere (< ?10 Ma old), the best-fitting power law exponent is insensitive to the age of the lithosphere, with the value of the exponent being between 14 and 16 when failing for thrust faulting for the flow laws of Kohlstedt et al [1995] and between 15 and 19 for more recently published flow laws. These results support the application of thin viscous sheet models to diffuse oceanic plate boundaries, such as the ones accommodating motion between the India, Capricorn, and Australia plates in the Indian Ocean.

Mishra, J. K.; Gordon, R. G.

2011-12-01

302

Rheology, and how to stop aging  

CERN Document Server

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 effective temperature. The approach does not invoke any particular geometry for the constituents of the fluid, provided it has glassy behaviour.

Kurchan, J

1998-01-01

303

Influence of electrolytes and membranes on cell operation for syn-gas production  

Energy Technology Data Exchange (ETDEWEB)

The impact of membrane type and electrolyte composition for the electrochemical generation of synthesis gas (CO + H2) using a Ag gas diffusion electrode are presented. Changing from a cation exchange membrane to an anion exchange membrane (AEM) extended the cell operational time at low Ecell values (up to 4x) without impacting product composition. The use of KOH as the catholyte decreased the Ecell and resulted in a minimum electrolyte cost reduction of 39%. The prime factor in determining operational time at low Ecell values was the ability to maintain a sufficiently high anolyte pH.

Eric J. Dufek; Tedd E. Lister; Michael E. McIlwain

2012-02-01

304

Iron-containing coatings obtained by microplasma method on aluminum with usage of homogeneous electrolytes  

Energy Technology Data Exchange (ETDEWEB)

The microplasma synthesis method of multicomponent oxide coatings including iron oxide on an aluminum alloy surface has been studied. The homogeneous electrolytes containing iron complexes with Edta{sup 4-} under pH 9-10 have been used. The dynamics reducing the pH of the electrolyte during formation process have been studied. The content of iron in the coatings has been measured spectrophotometricaly. Morphlogy and phase composition of the coatings have been studied by the scanning electron microscopy and X-ray powder diffraction.

Rogov, A.B., E-mail: alex-lab@bk.ru [Nikolaev Institute of Inorganic Chemistry, 3, Acad. Lavrentiev Ave, Novosibirsk, 630090 (Russian Federation); Terleeva, O.P., E-mail: oterleeva@yandex.ru [Nikolaev Institute of Inorganic Chemistry, 3, Acad. Lavrentiev Ave, Novosibirsk, 630090 (Russian Federation); Mironov, I.V., E-mail: imir@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, 3, Acad. Lavrentiev Ave, Novosibirsk, 630090 (Russian Federation); Slonova, A.I., E-mail: antaris@ngs.ru [Nikolaev Institute of Inorganic Chemistry, 3, Acad. Lavrentiev Ave, Novosibirsk, 630090 (Russian Federation)

2012-01-15

305

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

306

Electrolytic production of neodymium metal from a molten chloride electrolyte  

International Nuclear Information System (INIS)

This paper reports that the U.S. Bureau of Mines conducted experiments on electrowinning of neodymium metal by using a molten-metal cathode at 650 degrees C and an electrolyte of 50 mol pet NdCl, (neodymium chloride) and 50 mol pet KCl (potassium chloride). The molten-metal cathodes were alloys of magnesium and zinc or magnesium and cadmium. Current efficiencies were 90 pct with a Mg-Zn cathode and 80 pct with a Mg-Cd cathode. The Mg-Cd cathode was easily separated from the electrolyte. In contrast, the Mg-Zn cathode tended to mix with the electrolyte, making separation difficult. The cathode metals were separated from the neodymium by distillation at 1,100 degrees C under a vacuum of 10-4 torr. Neodymium metal of 99.9 + purity was recovered from the Mg-Cd alloy cathode after 30 min distillation time. The neodymium recovered from the Mg-Zn system contained almost 2 pct Zn after vacuum distillation. Continuous operation using the Mg-Cd alloy cathode was demonstrated

307

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

308

Electrolyte for niobium coating deposition  

International Nuclear Information System (INIS)

Electrolyte composition is devised, which permits to increase by an order (as compared with the known compositions) current efficiency in the process of niobium coating electrodeposition. The following ratio of the electrolyte components, g/l, is recommended: dicyclopentadienylniobiumdichloride 5-10, sodium perchlorate - 10-50, dimethylformamide or its mixture with methanol (4:1-20:1) - to 1 l. The process of electrodeposition is realized at the temperature 20-40 deg C and cathode current density 0.05 A/dm2 for 0.25-2 h. The cathode potential has the value 0.9-1.5 V (as to relatively saturated mercurous chloride electrode). Copper, platinum, graphite were used as the cathode materials, graphite - as the anode one. The results obtained are substantiated

309

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

310

Cerium ion conducting solid electrolyte  

International Nuclear Information System (INIS)

A cerium ion conducting solid electrolyte, (CexZr1-x)4/4-xNb(PO4)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(WO4)3 and R1/3Zr2(PO4)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

311

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

312

Electrolytic matrix for fuel cell  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to the improvement of a matrix retaining electrolyte of a fuel cell whose electrolyte is phosphoric acid. The invention offers a matrix in which, in order to improve its retainability of phosphoric acid, zirconium phosphate having good affinity with phosphoric acid is used and at least one of polyethersulfone and polyetherketon is included as consolidating agent. Since both polyethersulfone and polyetherketon have hydrophilic property, wettability of phosphoric acid is good and after forming a matrix on the electrodes, the specified amount of phosphoric acid can easily be impregnated. Besides, since these polymers have polarity, they couple firmly with zirconium phosphate increasing the mechanical strength of the matrix. (1 fig, 1 tab)

Iisaka, Katsuyoshi; Hirata, Kuniyuki; Koda, Norio; Kimura, Hiroshi

1988-02-08

313

Rheological Investigation on the Effect of Shear and Time Dependent Behavior of Waxy Crude Oil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheological measurements are essential in transporting crude oil, especially for waxy crude oil. Several rheological measurements have been conducted to determine various rheological properties of waxy crude oil including the viscosity, yield strength, wax appearance temperature (WAT), wax disappearance temperature (WDT), storage modulus and loss modulus, amongst others, by using controlled stress rheometers. However, a procedure to determine the correct parameters for rheological measurement...

Japper-Jaafar A.; Bhaskoro P.; Sariman M.Z.; Rozlee R.

2014-01-01

314

Rheological changes in irradiated chicken eggs  

Energy Technology Data Exchange (ETDEWEB)

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 results are discussed in terms of possible industrial applications.

Ferreira, Lucia F. S.; Del Mastro, Nelida L

1998-06-01

315

Improving feed slurry rheology by colloidal techniques  

International Nuclear Information System (INIS)

Pacific Northwest Laboratory (PSN) has investigated three colloidal techniques in the laboratory to improve the sedimentation and flowability of Hanford simulated (nonradioactive) current acid waste (CAW) melter feed slurry: polymer-induced bridging flocculation; manipulating glass former (raw SiO2 or frit) particle size; and alteration of nitric acid content. All three methods proved successful in improving the rheology of the simulated CAW feed. This initially had exhibited nearly worst-case flow and clogging properties, but was transformed into a flowable, resuspendable (nonclogging) feed. While each has advantages and disadvantages, the following three specific alternatives proved successful: addition of a polyelectrolyte in 2000 ppM concentration to feed slurry; substitution of a 49 wt % SiO2 colloidal suspension (approx. 10-micron particle size) for the -325 mesh (less than or equal to 44-micron particle size) raw-chemical SiO2; and increase of nitric acid content from the reference 1.06 M to optimum 1.35 M. The first method, polymer-induced bridging flocculation, results in a high sediment volume, nonclogging CAW feed. The second method, involving the use of colloidal silica particles results in a nonsedimenting feed that when left unagitated forms a gel. The third method, increase in feed acidity, results in a highly resuspendable (nonclogging) melter feed. Further research is therefore required to determine which of the three alternatives is the preferred method of achieving rheological control of CAW melter feeds

316

Study of the rheological properties of oil  

Energy Technology Data Exchange (ETDEWEB)

The author describes industrial research into the process of disturbing the thixotropic structure of oil in well L-3 during constant oil coagulation inside the ''Rheostat'' rotating cylindrical viscosity meter. This oil, containing paraffin, has a high viscosity and corresponds to the chemical classification for pseudo water plastic thixotropic flowing liquid. This research was conducted at temperatures of 15,20,25, and 30 degrees C. The final time period is determined for the disintegration of the oil structure, during which almost no indicator changes are detected by industrial metering devices. This process of disintegration was viewed by the author as a breakdown of the thixotropic structure during the given rate of coagulation. Metering results were approximated and found to be most significant in non-stationary processes over a relatively short period of time. The rheological curve is then often replaced by a straight angle. This article also examines certain factors in the transport of such oil and trunklines and the resulting effects upon that oil's rheological composition.

Jewulski, J.

1979-01-01

317

Plasma electrolytic oxidation of tantalum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

318

Plasma electrolytic oxidation of metals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

319

Review Of Rheology Modifiers For Hanford Waste  

Energy Technology Data Exchange (ETDEWEB)

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.

Pareizs, J. M.

2013-09-30

320

Development of magneto-rheological fluid composites with rigidification characteristics  

International Nuclear Information System (INIS)

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 forceso 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

 
 
 
 
321

Effect of a maltodextrin-electrolyte, a maltodextrin-nutrient-electrolyte and a standard electrolyte solution on water and electrolyte fluxes in the secreting rat intestine.  

Science.gov (United States)

The effects of a maltodextrin (dextrose equivalent 12)-electrolyte solution and a maltodextrin-electrolyte solution with added nutrients on net water and electrolyte transport in the secreting rat intestine was compared with the citrate-World Health Organization oral rehydration solution to determine the need for a clinical trial to evaluate the efficacy of these maltodextrin solutions in acute diarrhoea treatment. Cholera toxin consistently produced net water secretion (-36.5 +/- 9.9 mean +/- SEM microliter/min/g dry weight of intestine). All three solutions reversed the cholera toxin-induced net intestinal water secretion to net absorption. Significantly greater net water absorption occurred from the maltodextrin-electrolyte solution compared to the World Health Organization solution (P maltodextrin-electrolyte-nutrient solution. Net sodium, potassium and chloride fluxes due to the World Health Organization-solution were not significantly different from the maltodextrin-electrolyte solution. These data provide a rationale for initiating a clinical trial. PMID:8188993

Rolston, D D; Raghupathy, P; Cutting, W A

1993-12-01

322

Engineering the Electrode-Electrolyte Interface: From Electrode Architecture to Zinc Redox in Ionic Liquid Electrolytes  

Science.gov (United States)

The electrode-electrolyte interface in electrochemical environments involves the understanding of complex processes relevant for all electrochemical applications. Some of these processes include electronic structure, charge storage, charge transfer, solvent dynamics and structure and surface adsorption. In order to engineer electrochemical systems, no matter the function, requires fundamental intuition of all the processes at the interface. The following work presents different systems in which the electrode-electrolyte interface is highly important. The first is a charge storage electrode utilizing percolation theory to develop an electrode architecture producing high capacities. This is followed by Zn deposition in an ionic liquid in which the deposition morphology is highly dependant on the charge transfer and surface adsorption at the interface. Electrode Architecture: A three-dimensional manganese oxide supercapacitor electrode architecture is synthesized by leveraging percolation theory to develop a hierarchically designed tri-continuous percolated network. The three percolated phases include a faradaically-active material, electrically conductive material and pore-former templated void space. The micropores create pathways for ionic conductivity, while the nanoscale electrically conducting phase provides both bulk conductivity and local electron transfer with the electrochemically active phase. Zn Electrodeposition: Zn redox in air and water stable N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, [C2nmm][NTf2] is presented. Under various conditions, characterization of overpotential, kinetics and diffusion of Zn species and morphological evolution as a function of overpotential and Zn concentration are analyzed. The surface stress evolution during Zn deposition is examined where grain size and texturing play significant rolls in compressive stress generation. Morphological repeatability in the ILs led to a novel study of purity in ionic liquids where it is found that surface adsorption of residual amine and chloride from the organic synthesis affect growth characteristics. The drivers of this work are to understand the processes occurring at the electrode-electrolyte interface and with that knowledge, engineer systems yielding optimal performance. With this in mind, the design of a bulk supercapacitor electrode architecture with excellent composite specific capacitances, as well as develop conditions producing ideal Zn deposition morphologies was completed.

Engstrom, Erika

2011-12-01

323

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

324

Rheological study of a water based oil well drilling fluid  

Energy Technology Data Exchange (ETDEWEB)

Organic polymers are commonly used to control the rheology and filtrate loss required for water-based drilling fluids. An ecologically-friendly water-based drilling fluid was developed by studying the rheological behavior of tamarind gum and polyanionic cellulose on bentonite water suspensions. The effect of drilling fluid filtrate on formation damage was also analyzed. The drilling fluid that was developed has better rheological properties and fluid loss control which are required for optimum performance of oil well drilling. In addition, the drilling fluid filtrate exhibits minimum formation damage on sandstone cores.

Mahto, Vikas; Sharma, V.P. [Department of Petroleum Engineering, Indian School of Mines, Dhanbad-826004, Jharkhand (India)

2004-11-30

325

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

326

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

327

Chemical modification of electrolytes for lithium batteries  

International Nuclear Information System (INIS)

Modern approaches to modifying chemically electrolytes for lithium batteries are analysed with the aim of optimising the charge-transfer processes in liquid-phase and solid (polymeric) media. The main regularities of transport properties of lithium electrolyte solutions containing complex (encapsulated) ions in aprotic solvents and polymers are discussed. The prospects for the development of electrolytic solvosystems with the chain (ionotropic) mechanism of conduction with respect to lithium ions are outlined. The bibliography includes 126 references.

328

Novel Electrolytes for Lithium Ion Batteries  

Energy Technology Data Exchange (ETDEWEB)

We have been investigating three primary areas related to lithium ion battery electrolytes. First, we have been investigating the thermal stability of novel electrolytes for lithium ion batteries, in particular borate based salts. Second, we have been investigating novel additives to improve the calendar life of lithium ion batteries. Third, we have been investigating the thermal decomposition reactions of electrolytes for lithium-oxygen batteries.

Lucht, Brett L

2014-12-12

329

Solid electrolytes general principles, characterization, materials, applications  

CERN Document Server

Solid Electrolytes: General Principles, Characterization, Materials, Applications presents specific theories and experimental methods in the field of superionic conductors. It discusses that high ionic conductivity in solids requires specific structural and energetic conditions. It addresses the problems involved in the study and use of solid electrolytes. Some of the topics covered in the book are the introduction to the theory of solid electrolytes; macroscopic evidence for liquid nature; structural models; kinetic models; crystal structures and fast ionic conduction; interstitial motion in

Hagenmuller, Paul

1978-01-01

330

Electrolytic cell. [For separating anolyte and catholyte  

Science.gov (United States)

An apparatus is described for the separation of the anolyte and the catholyte during electrolysis. The electrolyte flows through an electrolytic cell between the oppositely charged electrodes. The cell is equipped with a wedge-shaped device, the tapered end being located between the electrodes on the effluent side of the cell. The wedge diverts the flow of the electrolyte to either side of the wedge, substantially separating the anolyte and the catholyte.

Bullock, J.S.; Hale, B.D.

1984-09-14

331

Advances in electrolyte cooling tower technology  

International Nuclear Information System (INIS)

Cooling towers play an important role in the production of metals by means of electrowinning. These towers are subject to severe operating conditions, and hence, standard cooling tower designs and practices are often not applicable. This paper reviews the operational requirements and conditions applicable to electrolyte cooling towers, specifically zinc electrolyte towers. Aspects covered include the physical factors influencing electrolyte cooling, cooling tower design, coupling of cooling towers to ventilation systems and environmental compliance requirements. (author)

332

Electrodeposition of Fe powder from acid electrolytes  

Directory of Open Access Journals (Sweden)

Full Text Available Polarization characteristics of the electrodeposition processes of Fe powders from sulfate and chloride electrolytes and the morphology of the obtained powders were investigated. The morphology depended on the anion presence in the electrolyte but not on the current density in the investigated range. A characteristic feature of the dendritic powder with cauliflower endings obtained from sulfate electrolyte is the presence of cone-like cavities and the crystallite morphology of the powders surface. On the other hand, Fe powders electrodeposited from chloride electrolyte appear in the form of agglomerates. A soap solution treatment applied as a method of washing and drying provides good protection from oxidation of the powders.

VESNA M. MAKSIMOVIC

2008-08-01

333

Ion transport phenomena in polymeric electrolytes  

International Nuclear Information System (INIS)

The aim of the present work is to generalize an ion transport phenomena observed in composite polymeric electrolytes using the previously developed models as well as design a new approach which would be helpful in describing changes in conductivity and lithium ion transference numbers occurring upon addition of fillers to polymeric electrolytes. The concept is based on the observation of changes in ionic associations in the polymeric electrolytes studied in a wide salt concentration range. The idea is illustrated by the results coming from a variety of electrochemical and structural data obtained for composite electrolytes containing specially designed inorganic and organic fillers

334

Electrolytic process for preparing uranium metal  

Science.gov (United States)

An electrolytic process for making uranium from uranium oxide using Cl.sub.2 anode product from an electrolytic cell to react with UO.sub.2 to form uranium chlorides. The chlorides are used in low concentrations in a melt comprising fluorides and chlorides of potassium, sodium and barium in the electrolytic cell. The electrolysis produces Cl.sub.2 at the anode that reacts with UO.sub.2 in the feed reactor to form soluble UCl.sub.4, available for a continuous process in the electrolytic cell, rather than having insoluble UO.sub.2 fouling the cell.

Haas, Paul A. (Knoxville, TN)

1990-01-01

335

Electrochemical cell with high conductivity glass electrolyte  

Science.gov (United States)

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with an ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

Nelson, P. A.; Bloom, I. D.; Roche, M. F.

1986-04-01

336

Rebalancing electrolytes in redox flow battery systems  

Energy Technology Data Exchange (ETDEWEB)

Embodiments of redox flow battery rebalancing systems include a system for reacting an unbalanced flow battery electrolyte with a rebalance electrolyte in a first reaction cell. In some embodiments, the rebalance electrolyte may contain ferrous iron (Fe.sup.2+) which may be oxidized to ferric iron (Fe.sup.3+) in the first reaction cell. The reducing ability of the rebalance reactant may be restored in a second rebalance cell that is configured to reduce the ferric iron in the rebalance electrolyte back into ferrous iron through a reaction with metallic iron.

Chang, On Kok; Pham, Ai Quoc

2014-12-23

337

Handbook of Aqueous Electrolyte Thermodynamics Theory & Application  

CERN Document Server

Expertise in electrolyte systems has become increasingly important in traditional CPI operations, as well as in oil/gas exploration and production. This book is the source for predicting electrolyte systems behavior, an indispensable "do-it-yourself" guide, with a blueprint for formulating predictive mathematical electrolyte models, recommended tabular values to use in these models, and annotated bibliographies. The final chapter is a general recipe for formulating complete predictive models for electrolytes, along with a series of worked illustrative examples. It can serve as a usef

Zemaitis, Joseph F; Rafal, Marshall

1986-01-01

338

Photocured Gelled Electrolytes For Secondary Li Cells  

Science.gov (United States)

Class of photocured polymers exhibiting lithium-ion conductivities greater than those of well-studied polymers based on polyethylene oxide (PEO) show promise as polymeric electrolytes in rechargeable lithium cells. Increase in conductivity occasioned by use of electrolytes, coupled with amenability of electrolytes to formation into uniform thin (less than 25 micrometers thick), wide films, expected to result in cells with power densities greater than 100 W h/kg and charge/discharge rates exceeding currents equal, in amperes, to ampere-hour ratings. All-solid-state lithium batteries containing these electrolytes used as high-power, high-rate rechargeable power sources in commercial and aerospace applications.

Nagasubramanian, Ganesan

1994-01-01

339

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.)

340

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

 
 
 
 
341

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

342

Rheology of Vimentin Intermediate Filament Networks  

Science.gov (United States)

A cell's ability to function is highly dependent on its structure and material properties - its capacity to withstand and respond to forces in its environment. The cytoskeleton, which largely determines the cellular mechanical properties, is comprised of biopolymer networks, including filamentous actin, microtubules, and intermediate filaments (IF). Intermediate filaments are much less studied than actin and microtubules. They are much more varied and specialized as well, and have been suggested as being an important platform in mechanotransduction processes in cells. It is thought that they can withstand very high strains and exhibit strain stiffening behavior. We are characterizing vimentin, a type III IF that is found in all vertebrate cells, using rheological techniques. Vimentin elasticity increases upon addition of multivalent cations, which act like molecular crosslinkers. By varying the concentration of cations, we can extract valuable information about how the networks assemble and function.

Wu, Huayin

2012-02-01

343

Dimorphic magnetorheological fluid with improved rheological properties  

International Nuclear Information System (INIS)

A type of dimorphic magnetorheological (MR) fluid was prepared by adding wire-like iron nanostructures into the conventional carbonyl iron based MR fluid. The Fe nanowires were synthesized through reducing Fe2+ ion with excessive sodium borohydride in aqueous solution. The rheological behaviors of the dimorphic MR fluids were measured with a rotational rheometer and the sedimentation properties were also studied in this work. It was found that the Fe wires additives can greatly enhance the stress strength of the dimorphic MR fluids comparing with the conventional MR fluids. The sedimentation of the dimorphic MR fluids was also mitigated greatly. - Highlights: ? Dimorphic MR fluids with enhanced MR effect were prepared. ? Fe nanowires and spherical carbonyl iron particles show a synergistic effect on improving the performance of MR fluid. ? Sedimentations of the dimorphic MR fluids were mitigated greatly.

344

Dimorphic magnetorheological fluid with improved rheological properties  

Energy Technology Data Exchange (ETDEWEB)

A type of dimorphic magnetorheological (MR) fluid was prepared by adding wire-like iron nanostructures into the conventional carbonyl iron based MR fluid. The Fe nanowires were synthesized through reducing Fe{sup 2+} ion with excessive sodium borohydride in aqueous solution. The rheological behaviors of the dimorphic MR fluids were measured with a rotational rheometer and the sedimentation properties were also studied in this work. It was found that the Fe wires additives can greatly enhance the stress strength of the dimorphic MR fluids comparing with the conventional MR fluids. The sedimentation of the dimorphic MR fluids was also mitigated greatly. - Highlights: > Dimorphic MR fluids with enhanced MR effect were prepared. > Fe nanowires and spherical carbonyl iron particles show a synergistic effect on improving the performance of MR fluid. > Sedimentations of the dimorphic MR fluids were mitigated greatly.

Jiang Wanquan, E-mail: jiangwq@ustc.edu.cn [Department of Chemistry, University of Science and Technology of China (USTC), Hefei 230026 (China); Zhang Yanli [Department of Chemistry, University of Science and Technology of China (USTC), Hefei 230026 (China); Xuan Shouhu; Guo Chaoyang [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, USTC, Hefei 230027 (China); Gong Xinglong, E-mail: gongxl@ustc.edu.cn [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, USTC, Hefei 230027 (China)

2011-12-15

345

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

346

Rheological effects in roll coating of paints  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english the aim of this work is the study of the problems that arise during roll coating application of paints on steel sheets. We put in evidence the particular effects due to the non-Newtonian properties of these fluids. At speeds above a certain critical value, the flow of paint through the applicator su [...] ffers a hydrodynamical instability called ribbing, which generates a patterned interface on the film applied. Threshold of instability as well as waveform of the pattern is function of rheological properties of paints as well as surface tension. Thixotropy of paints as well as shear-thinning behaviour has been determined for several industrial paints used in the steel industry, and correlated with levelling performance after application.

F., Varela López; M., Rosen.

2002-07-01

347

Rheological and microstructural properties of Irradiated starch  

International Nuclear Information System (INIS)

Gamma irradiation ia s fast and efficient method to improve the functional properties of straches. Wheat and potato starches were submitted, in the present study, at 3,5,10 and 20 kGy radiation dose. The changes induced by irradiation on the rheological properties of these starches showed a decrease in the viscosity with increasing radiation dose. Chemicals bond's hydrolysis has been induced by free radicals that have been identified by EPR. Wheat starch presents five EPR signals after irradiation, whiles potato starch has a weak EPR signal. On the other hand, irradiation caused decrease in amylose content. This decrease is more pronounced in potato starch. Dry irradiated starch's MEB revealed no change in the shape, size and distribution of the granules. While, the observation of wheat starch allowed the complete disappearance of the granular structure and the dissolution of its macromolecules after irradiation which justifies the significant decrease in wheat starch's viscosity irradiated at 20 kGy.

348

Interfacial behavior of polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Evidence is presented concerning the effect of surfaces on the segmental motion of PEO-based polymer electrolytes in lithium batteries. For dry systems with no moisture the effect of surfaces of nano-particle fillers is to inhibit the segmental motion and to reduce the lithium ion transport. These effects also occur at the surfaces in composite electrodes that contain considerable quantities of carbon black nano-particles for electronic connection. The problem of reduced polymer mobility is compounded by the generation of salt concentration gradients within the composite electrode. Highly concentrated polymer electrolytes have reduced transport properties due to the increased ionic cross-linking. Combined with the interfacial interactions this leads to the generation of low mobility electrolyte layers within the electrode and to loss of capacity and power capability. It is shown that even with planar lithium metal electrodes the concentration gradients can significantly impact the interfacial impedance. The interfacial impedance of lithium/PEO-LiTFSI cells varies depending upon the time elapsed since current was turned off after polarization. The behavior is consistent with relaxation of the salt concentration gradients and indicates that a portion of the interfacial impedance usually attributed to the SEI layer is due to concentrated salt solutions next to the electrode surfaces that are very resistive. These resistive layers may undergo actual phase changes in a non-uniform manner and the possible role of the reduced mobility polymer layers in dendrite initiation and growth is also explored. It is concluded that PEO and ethylene oxide-based polymers are less than ideal with respect to this interfacial behavior.

Kerr, John; Kerr, John B.; Han, Yong Bong; Liu, Gao; Reeder, Craig; Xie, Jiangbing; Sun, Xiaoguang

2003-06-03

349

Electrolytic production of metal oxides  

International Nuclear Information System (INIS)

Partially-conducting metal oxide, particularly magnetite in finely-divided form, is produced in a cell comprising a first electrode constituted substantially by the metal whose oxide is to be produced, an aqueous conductive electrolyte, and another electrode which evolves hydrogen and is inert, preferably austenitic steel. If the first electrode is steel contaminated with radioactive material, waste radioactive material in a form which is relatively convenient for handling and long-term storage is produced. The cell may be solar powered, for use in space. (Author)

350

Plasma electrolytic oxidation of tantalum  

Directory of Open Access Journals (Sweden)

Full Text Available 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. The oxide coatings are partly crystallized and mainly composed of WO3, Ta2O5 and SiO2.

Petkovi? Marija

2012-01-01

351

Emission properties of electrolytic rhenium  

International Nuclear Information System (INIS)

Studied are emission properties of a tubular cathode made of a chloride rhenium-containing melt by the galvanoplastic method. The vacuum density of the sample and a possibility of fusing it with niobium by means of electron-beam welding have been shown. The electron work function is found to make 4.94+-0.05 eV. The structure of the sample has been shown to be thermally stable. The experiments show that electrolyte rhenium can be applied as a material for cathodes of thermo-emission converters. There are possibilities of considerable improvement of its properties by precipitation of layers with highly perfect texture (0001)

352

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

353

Viscoelastic and rheological behavior of concentrated colloidal suspensions  

Science.gov (United States)

Molecular approaches are discussed to the density ( ?), viscoeleastic ( ?), and rheological ( ?) behavior of the viscosity ?( ?,?,?) of concentrated colloidal suspensions with 0.3 theore for ?( ?,?,?) is clearly needed and pursued.

de Schepper, I. M.; Cohen, E. G. D.

1994-11-01

354

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

355

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

356

Rheology and Contact Lifetime Distribution in Dense Granular Flows  

CERN Document Server

We study the rheology and distribution of interparticle contact lifetimes for gravity-driven, dense granular flows of non-cohesive 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.

Silbert, L E; Brewster, R; Levine, A J; Silbert, Leonardo E.; Grest, Gary S.; Brewster, Robert; Levine, Alex J.

2007-01-01

357

Innovative polymer nanocomposite electrolytes: nanoscale manipulation of ion channels by functionalized graphenes.  

Science.gov (United States)

The chemistry and structure of ion channels within the polymer electrolytes are of prime importance for studying the transport properties of electrolytes as well as for developing high-performance electrochemical devices. Despite intensive efforts on the synthesis of polymer electrolytes, few studies have demonstrated enhanced target ion conduction while suppressing unfavorable ion or mass transport because the undesirable transport occurs through an identical pathway. Herein, we report an innovative, chemical strategy for the synthesis of polymer electrolytes whose ion-conducting channels are physically and chemically modulated by the ionic (not electronic) conductive, functionalized graphenes and for a fundamental understanding of ion and mass transport occurring in nanoscale ionic clusters. The functionalized graphenes controlled the state of water by means of nanoscale manipulation of the physical geometry and chemical functionality of ionic channels. Furthermore, the confinement of bound water within the reorganized nanochannels of composite membranes was confirmed by the enhanced proton conductivity at high temperature and the low activation energy for ionic conduction through a Grotthus-type mechanism. The selectively facilitated transport behavior of composite membranes such as high proton conductivity and low methanol crossover was attributed to the confined bound water, resulting in high-performance fuel cells. PMID:21534602

Choi, Bong Gill; Hong, Jinkee; Park, Young Chul; Jung, Doo Hwan; Hong, Won Hi; Hammond, Paula T; Park, Hoseok

2011-06-28

358

Rheological behavior of blueberry Comportamento reológico de mirtilo  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The physical and physicochemical characteristics of blueberry (Vaccinium myrtillus) fruits produced in Brazil were analyzed. Rheological properties were measured at 5, 25, 45 and 65 °C, on a stress controlled rheometer equipped with grooved a stainless-steel parallel-plate in a shear rate range of 0-300 s-1, with the objective of determining the influence of temperature on the rheological properties. The pseudoplastic behavior with yield stress was well described by the Ostwald-de-Waele (Pow...

Graziella Colato Antonio; Flávia Regina Faria; Cristina Yoshie Takeiti; Kil Jin Park

2009-01-01

359

Rheological study of chitosan and its blends: An overview  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 rheolog...

El-hefian, Esam A.

2010-01-01

360

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

 
 
 
 
361

Steady Rheological Properties of Rotating Biological Contactor (RBC) Sludge  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rheological characterization of sewage sludge at different steps of wastewater treatment is important since it allows predicting and estimating sludge behavior when submitted to almost all treatment and disposal operations. Rotating biological contactor (RBC) is being widely used for wastewater treatment, which is a biological treatment process following primary treatment. The rheological characterization of RBC sludge at different solid contents (TSS = 32.2 g/L–50.2 g/L) and temperatur...

Al-sameraiy, Mukheled; Banat, Fawzi; Abu-jdayil, Basim

2010-01-01

362

Evaluating Physical, Rheological and Chemical Properties of Modified Bitumen  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In India, the methods for rheological characterization of bituminous binders are inadequate to characterize the bitumen. Hence a complete rheological study and characterization of bitumen using dynamic shear rheometer would be helpful. Also there is limited insight about the chemistry of modified bitumen. Modification of asphalt binders can serve several purposes. It can increase the overall performance of a binder by widening the range between the binder?s high and low-temperature grades. In...

Maninder Singh

2012-01-01

363

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

364

The rheological properties of silated hydroxypropylmethylcellulose tissue engineering matrices  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes the rheological properties of silated hydroxypropylmethylcellulose (HPMC-Si) used in biomaterials domain as a three-dimensional synthetic matrix for tissue engineering. The HPMC-Si is an HPMC grafted with 3-glycidoxypropyltrimethoxysilane (GPTMS). HPMC and HPMC-Si were studied. It is shown that although silanization reduces the hydrodynamic volume in dilute solution, it does not affect significantly the rheological behavior of the concentrated solutions. The HPMC-Si visco...

Fatimi, Ahmed; Tassin, Jean-franc?ois; Quillard, Sophie; Axelos, Monique; Weiss, Pierre

2008-01-01

365

Viscoplastic modelling of granular column collapse with pressure dependent rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose a mechanical and numerical model of dry granular flows that quantitatively reproduces laboratory experiments of granular column collapse over inclined planes, with rheological parameters directly derived from the experiments. We reformulate the so-called µ(I) rheology in the framework of Drucker-Prager plasticity with yield stress and a viscosity ?(||D||, p) depending on both the pressure p and the norm of the strain rate tensor ||D||. The gran-ular domain, the velocities, the st...

Ionescu, Ioan; Mangeney, Anne; Bouchut, Franc?ois; Roche, Olivier

2014-01-01

366

Modelling the linear viscoelastic rheological properties of bituminous binders  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheology involves the study and evaluation of the flow and permanent deformation of time-and temperature-dependent materials, such as bitumen, that are stressed through the application of a force. The fundamental rheological properties of bituminous materials including bitumen are normally measured using a dynamic shear rheometer (DSR), from low to high temperatures. DSR is a powerful tool to measure elastic, viscoelastic and viscous properties of binders over a wide range of temperatures and...

Md Yusoff, Nur Izzi

2012-01-01

367

Electrochemical and rheological behaviour of a fluid zinc paste; Comportement electrochimique et rheologique d`une pate de zinc fluide  

Energy Technology Data Exchange (ETDEWEB)

Zinc is a performing anodic material in numerous types of batteries. The anode of alkaline cells is typically a suspension of metallic powder in a gelled potassium hydroxide electrolyte, called zinc paste. We process such a homogeneous, fluid and stable paste, we study its physical electrochemical and rheological properties. Electrical power delivered during galvano-static electrolysis is about a few tens of mW.cm{sup -2} for anodic overvoltages inferior to 200 mV until the complete oxidation of the metal, 10 oxidation-reduction cycles are realised on paste samples of few mm width. In other respects, the product has a Bingham-type flow behavior, of critical shearing stress close to 200 Pa, and plastic viscosity about Pa.s, valid from 0,1 s{sup -1} shear rate. Zinc paste circulates in a slim rectangular section channel. Movement is ensured by a peristaltic pump placed on a cylindrical flexible tube. The paste transit between rectangular and circular sections is made through a profiled mechanical piece called a fish tail, without draft edge or roughness. An electrolytic separator and a current collector form the walls of the parallelopipedal channel, thus an electrolysis cell is framed. We record electrical and rheological characteristics of 2 oxidation-reduction cycles, during which the paste continues to flow and remains conductive. Established performances on the elementary cell allow to make up an air-zinc circulating paste battery for an electrical vehicle: the hydraulic recharge of a 100 l anodic paste tank is made in a few minutes, corresponding to a 300 km autonomy. (author) 87 refs.

Sajot, N.

1997-12-04

368

Supercapacitor behavior of ?-MnMoO{sub 4} nanorods on different electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: SEM image of ?-MnMoO{sub 4} nanorods on FTO substrate. Highlights: ? Synthesis of ?-MnMoO{sub 4} nanorods by spin coating method. ? First study on the effect of electrolyte on the pseudocapacitance behavior. ? ?-MnMoO{sub 4} nanorods exhibit maximum specific capacitance of 998 F/g. ? At higher scan rates p-TSA electrolyte exhibits superior capacitive behavior. -- Abstract: ?-MnMoO{sub 4} 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 ?-MnMoO{sub 4} nanorods was studied using para toluene sulfonic acid (p-TSA), sulfuric acid (H{sub 2}SO{sub 4}) and hydrochloric acid (HCl) as electrolytes. X-ray diffraction analysis reveals the formation of ?-MnMoO{sub 4} 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. ?-MnMoO{sub 4} nanorods exhibit maximum specific capacitance of 998 F/g at a scan rate of 5 mV/s in H{sub 2}SO{sub 4} 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 H{sub 2}SO{sub 4}.

Purushothaman, K.K., E-mail: purushoth_gri@yahoo.co.in [Department of Physics, TRP Engineering College (SRM Group), Irungalur, Trichy, Tamilnadu (India); Cuba, M. [Department of Physics, Gandhigram Rural Institute – Deemed University, Gandhigram, Tamilnadu (India); Muralidharan, G., E-mail: muralg@rediffmail.com [Department of Physics, Gandhigram Rural Institute – Deemed University, Gandhigram, Tamilnadu (India)

2012-11-15

369

Improvement by heating of the electronic conductivity of cobalt spinel phases, electrochemically synthesized in various electrolytes  

International Nuclear Information System (INIS)

The nature of the alkaline electrolyte (based on KOH, NaOH, LiOH), in which Co3O4 spinel type phases are synthesized by electrooxidation of CoO, is shown to play a key role on the composition, the structure and the electronic conductivity of the materials. In the materials, prepared in pure LiOH electrolyte or in mixed ternary electrolyte (KOH, NaOH, LiOH), Co4+ ions are present in the octahedral framework, which entails electronic delocalization in the cobalt T2g band and a high conductivity. The structure of the sample, synthesized in KOH, is on the opposite closer to that of ideal Co3O4, with only Co3+ in the octahedral sublattice, which leads to a semi-conducting behavior. Whatever the initial material, a thermal treatment induces an increase of the Co4+/Co3+ ratio in the octahedral network, resulting in a significant increase of the electronic conductivity. - Graphical abstract: In 'Co3O4' type spinel phases synthesized by eleectrooxidation, the nature of the alkaline electrolyte allows to monitor the amounts of hydrogen and lithium, inserted in spinel framework and therefore the electronic conductivity. Whatever the initial synthesis electrolyte, a moderate thermal treatment of the materials induces a significant increase of the electronic conductivity, due to a structural reorganization (illustrated by the evolution of the cell parameter) andy the evolution of the cell parameter) and an increase of the Co4+/Co3+ ratio in the octahedral framework.

370

Multivariant simulator for vacuum cooling processes of three component electrolyte systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a computer aided analysis and synthesis of the crystallization processes from multicomponent electrolyte systems were studied. In addition, the vacuum crystallization processes with adiabatic cooling of the system are presented. The cooling process of a multicomponent electrolyte system can be considered as a process with the concentration of the system and/or the crystallization of the solid phase from the system. Requirements for multivariant options of the process simulator are the result of practical needs in the design of new processes or the improvement of exploitation processes. According to this, there are needs for a simulation of a simple flashing of the system as well as for the vacuum cooling crystallization processes with the cyclic structure. The possibilities of the created process simulator are illustrated on three component electrolyte systems. Application of the process simulator for any other electrolyte systems requires only an update of the thermodynamic model, and physico-chemical properties related to electrolyte system.

Suljkanovi? Midhat

2010-01-01

371

Fast protonic conducting solid electrolytes  

Science.gov (United States)

Theoretical and experimental research on glassy and crystalline solid electrolytes materials has been pursued. In lithium aluminum silicate we found that the presence of disorder in the aluminosilicate framework can exert substantial effects on the conductivity of the lithium ion; in particular the activation energy for ionic motion is substantially lower in the glassy phase than in the crystalline one, despite the greater disorder in the glass. This was explained in terms of reduced effects of interionic correlation in the disordered material compared to the rigidly alternating crystal. This substantial reduction in the localizing effects of ionic correlations should be operative in all glasses, and may account for enhancements of conductivity in stoichiometric glass compositions at relatively low temperatures. Complex impedance spectroscopy, magnetic resonance, vibrational spectroscopy and differential anomalous scattering techniques have been used to study local structures in silver selenide-germanium selenide glasses. The data seems to show the coexistence of well-defined local order with typical glassy randomness. Diffusion measurements on both uranyl phosphate and beta alumina protonic electrolytes were completed using nuclear magnetic resonance spectroscopy. The results strongly suggest that the Grotthus mechanism is not operative here. A detailed study of the transport properties of the proton conducting hydrogen-uranyl-periodate-water glasses was made.

Ratner, Mark A.; Whitmore, Donald H.

372

Plasma electrolytic oxidation of metals  

Directory of Open Access Journals (Sweden)

Full Text Available 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 determination of electron temperature, electron number density, spatial density of micro-discharges, the active surface covered by micro-discharges, and dimensional distribution of micro-discharges at various stages of PEO process. Special attention was focused on the results of the study of the morphology, chemical, and phase composition of oxide layers obtained by PEO process on aluminum, tantalum, and titanium in electrolytes containing tungsten. Physicochemical methodes: atomic force microscopy (AFM, scanning electron microscopy (SEM-EDS, x-ray diffraction (XRD, x-ray photoelectron spectroscopy (XPS, and Raman spectroscopy served as tools for examining obtained oxide coatings. Also, the application of the obtained oxide coatings, especially the application of TiO2/WO3 coatings in photocatalysis, were discussed.

Stojadinovi? Stevan

2013-01-01

373

Study and development of a hydrogen/oxygen fuel cell in solid polymer electrolyte technology  

Energy Technology Data Exchange (ETDEWEB)

The hydrogen/oxygen fuel cell appears today as the best candidate to the replacing of the internal combustion engine for automobile traction. This system uses the non explosive electrochemical recombination of hydrogen and oxygen. It is a clean generator whom only reactive product is water. This thesis shows a theoretical study of this system, the synthesis of different kinds of used electrodes and finally an analysis of water movements in polymer electrolyte by different original technologies. 70 refs., 73 figs., 15 tabs.

Mosdale, R.

1992-10-29

374

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

375

ThO2-based solid electrolyte  

International Nuclear Information System (INIS)

A ThO2-based fixed electrolyte contains 0.1 to 25 mol% of at least one of yttrium and magnesium oxides and 5 to 40 mol% of one of alkali earth and lanthanide oxides. The electrolyte not only has a high ion oxygen conductivity but also lower sintering interval. (J.P.)

376

Method of regenerating electrolytic decontaminating liquid  

International Nuclear Information System (INIS)

Purpose: To reduce the amount of secondary wastes and decrease the cost by the recovery of a liquid electrolyte, by regenerating the degraded liquid electrolyte used for the metal decontamination while utilizing the diffusion osmosis and diaphragm electrolysis. Method: When metal wastes produced from a nuclear power plant are electrolytically decontaminated, contaminating materials on the metal surfaces are transferred into the liquid electrolyte. The electrolytic decontaminating liquid is introduced into the diffusion osmotic vessel and separated into acidic ingredients (H2SO4, H3PO4) and metal ion components. Then, the acid components are transferred to a portion between the cation exchange membrane and anion exchange membrane in the diaphragm electrolytic cell, and the metal ion components are transferred to a portion between the anionic exchange membranes and the cathode. The anions contained so far in the metal ions (SO42-, PO42-) are accumulated between the anionic exchange membrane and the cationic ion exchange membrane and then returned to the electrolytic cell after having been converted into acid components (H2SO4, H3PO4) as the liquid electrolyte. While on the other hand, metal ions are formed into metal hydroxides to discharge and then discharged out of the system. (Kamimura, M.)

377

Electrodeposition of Palladium Coatings from Iminodiacetate Electrolyte  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ionic composition of an iminodiacetate electrolyte as a function of solution composition and pH has been deter-mined. The kinetic parameters (exchange currents and apparent transfer coefficients) of the electroreduction of a palla-dium(II) bis-iminodiacetate complex from an electrolyte ...

Kublanovsky, Valeriy S.; Nikitenko, Vasiliy N.; Rudenko, Kostiantyn P.

2013-01-01

378

F4U production by electrolytic reduction  

International Nuclear Information System (INIS)

As a part of the nuclear fuel cycle program developed at the Spanish Atomic Energy Commission it has been studied the electrolytic reduction of U-VI to U-IV. The effect of the materials, electrolyte concentration, pH, current density, cell size and laboratory scale production is studied. The Pilot Plant and the production data are also described. (Author) 18 refs

379

Review Of Rheology Models For Hanford Waste Blending  

Energy Technology Data Exchange (ETDEWEB)

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; o From single source tanks that feed the qualification tanks; o 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 experie

Koopman, D. C.; Stone, M.

2013-09-26

380

Highly flexible, proton-conductive silicate glass electrolytes for medium-temperature/low-humidity proton exchange membrane fuel cells.  

Science.gov (United States)

We demonstrate highly flexible, proton-conductive silicate glass electrolytes integrated with polyimide (PI) nonwoven fabrics (referred to as "b-SS glass electrolytes") for potential use in medium-temperature/low-humidity proton exchange membrane fuel cells (PEMFCs). The b-SS glass electrolytes are fabricated via in situ sol-gel synthesis of 3-trihydroxysilyl-1-propanesulfonic acid (THPSA)/3-glycidyloxypropyl trimethoxysilane (GPTMS) mixtures inside PI nonwoven substrates that serve as a porous reinforcing framework. Owing to this structural uniqueness, the b-SS glass electrolytes provide noticeable improvements in mechanical bendability and membrane thickness, in comparison to typical bulk silicate glass electrolytes that are thick and easily fragile. Another salient feature of the b-SS glass electrolytes is the excellent proton conductivity at harsh measurement conditions of medium temperature/low humidity, which is highly important for PEMFC-powered electric vehicle applications. This beneficial performance is attributed to the presence of a highly interconnected, proton-conductive (THPSA/GPTMS-based) silicate glass matrix in the PI reinforcing framework. Notably, the b-SS glass electrolyte synthesized from THPSA/GPTMS = 9/1 (mol/mol) exhibits a higher proton conductivity than water-swollen sulfonated polymer electrolyte membranes (here, sulfonated poly(arylene ether sulfone) and Nafion are chosen as control samples). This intriguing behavior in the proton conductivity of the b-SS glass electrolytes is discussed in great detail by considering its structural novelty and Grotthuss mechanism-driven proton migration that is strongly affected by ion exchange capacity (IEC) values and also state of water. PMID:23672268

Lee, Hyeon-Ji; Kim, Jung-Hwan; Won, Ji-Hye; Lim, Jun-Muk; Hong, Young Taik; Lee, Sang-Young

2013-06-12

 
 
 
 
381

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

382

LiNi0.5Mn1.5O4 spinel cathode using room temperature ionic liquid as electrolyte  

International Nuclear Information System (INIS)

In this study, LiNi0.5Mn1.5O4 (LNMO) nanoparticles were prepared as a 5 V cathode material via a rheological phase method and annealed at different temperatures: 680 °C, 750 °C, and 820 °C. The sample annealed at 750 °C shows the best performance. A room temperature ionic liquid (RTIL) containing 1 M lithium bis(trifluoromethanesulfonyl) imide (LiNTf2) in N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide (C4mpyrNTf2) was used as novel electrolyte in conjunction with the LNMO cathodes and their electrochemical properties have been investigated. The results show that the LNMO using RTIL as electrolyte has better coulombic efficiency and comparable discharge capacities to those of the cells assembled with standard liquid electrolyte (1 M LiPF6 in ethylene carbonate/diethyl carbonate). Electrochemical impedance spectroscopy shows that the RTIL is much more stable as the electrolyte for LiNi0.5Mn1.5O4 than the conventional electrolyte

383

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

2007-12-01

384

Rheological Characterization of Drag-Reducing Fluids.  

Science.gov (United States)

The efficient design and commercialization of processes involving flow of dilute polymer solutions are based on a fundamental understanding of the complex rheological behavior of these fluids. Of particular importance are situations associated with the drag reduction phenomenon, because of the potential for significant energy savings. In this research the important rheological characteristics of dilute polymer solutions are investigated in ways that are meaningful for applications to drag reducing conditions. The approach used is an alternative to conventional viscometric techniques, which are unsuccessful in measuring elastic properties of such fluids. The steady streaming flow, manifested by fluid nonlinearities, is employed as a model nonviscometric flow for studying the response of polymer solutions. Flow reversal and several common features with turbulence, make this flow particularly interesting for non-Newtonian fluids. Fluid elasticity is determined by measuring the steady streaming velocity profiles and then fitting theoretical predictions to data, which reveals the relevant relaxation times. The Maxwell and Oldroyd models are employed, as special cases of a generalized Giesekus model, involving Gordon-Schowalter derivatives. The special features of these derivatives were found to have no effect on steady streaming. The experimental system is based on laser Doppler velocimetry and a photographic technique. The polymers are well characterized aqueous solutions of polyacrylamide or polyethylene oxide. Results show that elasticity increases with concentration or frequency. They also prove that the models used can adequately describe the features of steady streaming. A comparison with pipe flow experiments reveals an interesting correlation between elasticity and drag reduction, which suggests that ranking polymers according to their elasticity provides sufficient information on their drag reducing effectiveness. The relaxation times from this work seem to be more appropriate in characterizing polymer response in drag reducing flows, than the "longest relaxation time", estimated from viscometry. No stretching occurs as a result of the primary flow. Of special interest are surfactants, because of their shear and thermal stability. Aqueous mixtures of cetyltrimethylammonium bromide and sodium salicylate are found to behave like polymers. Therefore, the elasticity -drag reduction correlation holds for surfactants as well. No evidence of flow-induced structure is found.

Vlassopoulos, Dimitris

385

Impact of Rheological Modifiers on Various Slurries Supporting DOE Waste Processing  

International Nuclear Information System (INIS)

Controlling the stability and subsequent rheological properties of slurries has been an important but challenging issue in nuclear waste treatment, one that previous research has yet to sufficiently address. At the Hanford and Savannah River sites, operation of the waste treatment facilities at increased solids loading reduces the evaporative load on the melter systems and thereby increases waste processing rates. However, at these higher solids loadings, increased slurry rheology becomes a significant processing issue. The current study evaluates the use of several rheological modifiers to alleviate increased slurry rheology at high waste solids concentrations. Rheological modifiers change particle interactions in slurry. For colloidal slurries, modifiers mainly alter the electrostatic and steric interactions between particles, leading to a change in slurry rheology. Weak organic acid type rheological modifiers strengthen electrostatic repulsion whereas nonionic/polymer surfactant type rheological modifiers introduce a steric repulsion. We investigated various rheological modifiers using high level waste (HLW) nuclear waste simulants characterized typically by high ionic strength and a wide range of pH from 4 to 13. Using rheological analysis, it was found that citric acid and polyacrylic acid would be good rheological modifiers for the HLW simulants tested, effectively reducing slurry rheology by 40% or more. Physical insights into the mechanisms driving stabilizatits into the mechanisms driving stabilization by these rheological modifiers will be discussed.

386

Catalyzed electrolytic plutonium oxide dissolution  

International Nuclear Information System (INIS)

Catalyzed electrolytic plutonium oxide dissolution (CEPOD) was first demonstrated at Pacific Northwest Laboratory (PNL) in early 1974 in work funded by the Exxon Corporation. The work, aimed at dissolution of Pu-containing residues remaining after the dissolution of spent mixed-oxide reactor fuels, was first publicly disclosed in 1981. The process dissolves PuO2 in an anolyte containing small (catalytic) amounts of elements that form kinetically fast, strongly oxidizing ions. These are continuously regenerated at the anode. Catalysts used, in their oxidized form, include Ag2+, Ce4+, Co3+, and AmO22+. This paper reviews the chemistry involved in CEPOD and the results of its application to the dissolution of the Pu content of a variety of PuO2-containing materials such as off-standard oxide, fuels dissolution residues, incinerator ash, contaminated soils, and other scraps or wastes. Results are presented for both laboratory-scale and plant-scale dissolves

387

LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES  

Energy Technology Data Exchange (ETDEWEB)

This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and Testing of Planar Single Cells. During this time period substantial progress has been made in developing low temperature deposition techniques to produce dense, nanocrystalline yttrium-stabilized zirconia films on both dense oxide and polymer substrates. Progress has been made in the preparation and characterization of thin electrolytes and porous LSM substrates. Both of these tasks are essentially on or ahead of schedule. In our proposal, we suggested that the ZrO{sub 2}/Sc system needed to be considered as a candidate as a thin electrolyte. This was because microcrystalline ZrO{sub 2}/Sc has a significantly higher ionic conductivity than YSZ, particularly at the lower temperatures. As a result, some 0.5 micron thick film of ZrO{sub 2}/16% Sc on an alumina substrate (grain size 20nm) was prepared and the electrical conductivity measured as a function of temperature and oxygen activity. The Sc doped ZrO{sub 2} certainly has a higher conductivity that either 20nm or 2400nm YSZ, however, electronic conductivity dominates the conductivity for oxygen activities below 10{sup -15}. Whereas for YSZ, electronic conductivity is not a problem until the oxygen activity decreases below 10{sup -25}. These initial results show that the ionic conductivity of 20nm YSZ and 20nm ZrO{sub 2}/16% Sc are essentially the same and the enhanced conductivity which is observed for Sc doping in microcrystalline specimens is not observed for the same composition when it is nanocrystalline. In addition they show that the electronic conductivity of Sc doped ZrO{sub 2} is at least two orders of magnitude higher than that observed for YSZ. The conclusion one reaches is that for 0.5 to 1 micron thick nanocrystalline films, Sc doping of ZrO{sub 2} has no benefits compared to YSZ. As a result, electrolyte films of ZrO{sub 2}/Sc should not be considered as candidates. However, they have the potential of being useful as an interface on the anode side of the electrolyte. NexTech has focused much of its effort during the past few months on establishing tape casting methods for porous LSM substrates. This work, performed under a separate DOE-funded program, involved tape casting formulations comprising LSM powders with bi-modal particle size distributions and fugitive pore forming additives. Sintered LSM substrates with porosities in the 30 to 40 vol% range, and pore sizes of 10 {approx} 20 microns have been prepared. In addition, tape casting formulations involving composite mixtures of LSM and Sm-doped ceria (SDC) have been evaluated. The LSM/SDC cathode substrates are expected to provide better performance at low temperatures. Characterization of these materials is currently underway.

Harlan U. Anderson

2000-03-31

388

Mixed metal fluorides as solid state electrolyte in battery application  

Energy Technology Data Exchange (ETDEWEB)

Solid-state based battery technology offers, in principle, the largest temperature range (from room temperature to 500 C) of any battery technology. In fluoride based batteries, the chemical reaction used to create electrical energy is a solid-state reaction of a metal with fluoride anion. Among the various types of solid preparation techniques, the mechanochemical synthesis has been recognized as a powerful route to novel, high-performance, and low-cost materials. Thus, a mixed and highly disordered fluoride phase with retained cubic symmetry can be obtained with a very high F{sup -} diffusivity. In our group, a series of new electrolytes was developed, namely LaF{sub 3}-BaF{sub 2}KF solid solutions, using mechanosynthesis method. The cubic structure of the product was confirmed by XRD. The nanoscale nature and morphology of the samples were characterized by SEM and TEM. First Solid-state electrochemical cells were built with LiF based composite cathode, LaF{sub 3}-BaF{sub 2}KF derived electrolyte and Fe based composite anode. (orig.)

Wang, Dechao; Reddy, M. Anji; Sepelak, V.; Hahn, H.; Fichtner, M. [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Nanotechnologie

2010-07-01

389

Rheological characterization of hydraulic fracturing slurries  

Energy Technology Data Exchange (ETDEWEB)

Few studies have dealt with the flow behavior of concentrated suspensions or slurries prepared with non-Newtonian carrier fluids. Therefore, the purpose of this investigation is to present experimental results obtained by pumping various hydraulic fracturing slurries into a fracture model and gathering data on differential pressure vs. flow rate. Several concentrations of hydroxypropyl guard (HPG), a wide range of proppant concentrations, and three test temperatures were studies. The effects of such variables as polymer gelling-agent concentration, proppant concentration, test temperature, and fracture-flow shear rate on the rheological properties of slurries were investigated. The correlations for predicting the relative slurry viscosity for these HPG fluids are presented. Substantial increases in viscosity of fracturing gels were observed, and results are discussed in light of several affecting variables. Results also are compared with those available for Newtonian and non-Newtonian concentrated suspensions. Applications of these correlations to estimate the hindered particle-settling velocity in the fracture caused by the presence of surrounding particles also is discussed. The correlations presented can easily be included in any currently available 2D or 3D fracture-design simulators; thus, the information can be applied directly to predict fracture geometry and extension.

Shah, S.N. (Halliburton Services, Duncan, OK (United States). Research and Engineering Dept.)

1993-05-01

390

Microfluidic Rheology of Soft Colloidal Suspensions  

Science.gov (United States)

The rheology of a suspension of soft colloidal particles is investigated using a pressure-driven flow in a deep 25 ?m wide microchannel. The system is composed of N-isopropylacrylamide (NIPA), colloidal microgel particles, suspended in aqueous solution. NIPA is temperature-sensitive in that the hydrodynamic radius of a particle decreases as temperature increases [1]. Therefore, colloidal suspensions of different packing fraction can be obtained simply by varying the temperature using a temperature-controlled stage. We determine the velocity profile and the local shear rate of the suspension using particle image velocimetry (PIV). We have developed methods to accurately infer the suspension shear viscosity and shear stress as a function of shear rate. The dynamical range of shear rates probed is approximately 5 orders of magnitude, ranging from 10-3 to 10^2 s-1. Results show that as the packing fraction is increased towards the jamming point, the velocity profiles are markedly non-Newtonian. Further, near the jamming point, the stress versus shear rate curves show yield stress behavior. [1] Alsayed, A.M., Islam, M.F., Zhang, J., Collings, P.J., Yodh, A.J., Science 309, 1207.-1210 (2005)

Nordstrom, Kerstin; Arratia, Paulo; Verneuil, Emilie; Gollub, Jerry; Durian, Douglas

2008-11-01

391

Rheology of Soft Suspensions near Jamming  

Science.gov (United States)

The rheology of a suspension of soft colloidal particles is investigated using a pressure-driven flow in a deep 25 ?m wide microchannel. The system is composed of N-isopropylacrylamide (NIPA) colloidal microgel particles, suspended in aqueous solution. NIPA is temperature-sensitive in that the hydrodynamic radius decreases as temperature increases [1]. Therefore, colloidal suspensions of different packing fraction can be obtained simply by varying the temperature using a temperature-controlled stage. We determine the velocity profile and the local shear rate of the suspension using particle image velocimetry (PIV). We have developed methods to accurately infer the suspension shear viscosity and shear stress as a function of shear rate. The dynamical range of shear rates probed is approximately 5 orders of magnitude, ranging from 10-4 to 10^1 s-1. Results show that as the packing fraction is increased towards the jamming point, the velocity profiles are markedly non-Newtonian. Further, above the jamming point, the stress versus shear rate curves show yield stress behavior. [1] Alsayed, A.M.;Islam, M.F.;Zhang, J.;Collings, P.J.;Yodh, A.J., Science 2005.

Nordstrom, Kerstin; Verneuil, Emilie; Arratia, Paulo; Gollub, Jerry; Durian, Douglas

2009-03-01

392

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

393

Predictability of Complex Modulus Using Rheological Models  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to investigate the advantages and disadvantages of several linear visco-elastic rheological models applied to the unmodified and polymer-modified bitumens. It was found that all the models studied can be used to predict the linear visco-elastic of unmodified bitumens, aged and unaged samples reasonably well. In contrary, this condition was not really applicable on polymer-modified bitumens particularly for the unaged samples. The measured and predicted data was assessed using the discrepancy ratio (Ri, Mean Normalized Error (MNE and Average Geometric Deviation (AGD goodness of fitting statistical analysis. From the study, the modified Sigmoidal and Generalized Logistic Sigmoidal models were observed to be the most outstanding models, followed by the Christensen Anderson and Marasteanu (CAM, Christensen and Anderson (CA and 2S2P1D (2 springs, 2 parabolic elements and 1 spring models. The presence of semi-crystalline waves and elastomeric structures in the mixtures render the breakdown of time temperature equivalency principle.

N.I.Md. Yusoff

2010-01-01

394

Rheological properties of cold recycled mixtures  

Directory of Open Access Journals (Sweden)

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

395

Influence of Fat Content on Chocolate Rheology  

Science.gov (United States)

Molten chocolate is a suspension having properties strongly affected by particle characteristics including not only the dispersed particles but also the fat crystals formed during chocolate cooling and solidification. Even though chocolate rheology is extensively studied, mainly viscosity at high temperature was determined and no information on amount and type of fat crystals can be detected in these conditions. However chocolate texture and stability is strongly affected by the presence of specific crystals. In this work a different approach, based on creep test, was proposed to characterize chocolate samples at typical process temperatures (approximately 30 °C). The analysis of compliance, as time function, at short times enable to evaluate a material "elasticity" related to the solid-like behavior of the material and given by the differential area between the Newtonian and the experimental compliance. Moreover a specific time dependent elasticity was defined as the ratio between the differential area, in a time range, and total area. Chocolate samples having a different fat content were prepared and they were conditioned directly on rheometer plate by applying two different controlled cooling rate; therefore creep were performed by applying a low stress to ensure material linear behavior. Experimental data were analyzed by the proposed method and specific elasticity was related to single crystal properties. It was found that fat crystal amount and properties depend in different way on fat content and cooling rate; moreover creep proved to be able to detect even small differences among tested samples.

Gabriele, D.; Migliori, M.; Baldino, N.; de Cindio, B.

2008-07-01

396

Apparatus for the electrolytic production of metals  

Energy Technology Data Exchange (ETDEWEB)

Improved electrolytic cells for producing metals by the electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells, at least one electrode includes a protective layer comprising an oxide of the cell product metal formed upon an alloy of the cell product metal and a more noble metal. In the case of an aluminum reduction cell, the electrode can comprise an alloy of aluminum with copper, nickel, iron, or combinations thereof, upon which is formed an aluminum oxide protective layer. 5 figures.

Sadoway, D.R.

1993-10-19

397

Apparatus for the electrolytic production of metals  

Energy Technology Data Exchange (ETDEWEB)

Improved electrolytic cells for producing metals by the electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells, at least one electrode includes a protective layer comprising an oxide of the cell product metal formed upon an alloy of the cell product metal and a more noble metal. In the case of an aluminum reduction cell, the electrode can comprise an alloy of aluminum with copper, nickel, iron, or combinations thereof, upon which is formed an aluminum oxide protective layer.

Sadoway, Donald R. (Belmont, MA)

1993-01-01

398

Electrolytic orthoborate salts for lithium batteries  

Science.gov (United States)

Orthoborate salts suitable for use as electrolytes in lithium batteries and methods for making the electrolyte salts are provided. The electrolytic salts have one of the formulae (I). In this formula anionic orthoborate groups are capped with two bidentate chelating groups, Y1 and Y2. Certain preferred chelating groups are dibasic acid residues, most preferably oxalyl, malonyl and succinyl, disulfonic acid residues, sulfoacetic acid residues and halo-substituted alkylenes. The salts are soluble in non-aqueous solvents and polymeric gels and are useful components of lithium batteries in electrochemical devices.

Angell, Charles Austen [Mesa, AZ; Xu, Wu [Tempe, AZ

2009-05-05

399

Electrodeposition of Palladium Coatings from Iminodiacetate Electrolyte  

Directory of Open Access Journals (Sweden)

Full Text Available The ionic composition of an iminodiacetate electrolyte as a function of solution composition and pH has been deter-mined. The kinetic parameters (exchange currents and apparent transfer coefficients of the electroreduction of a palla-dium(II bis-iminodiacetate complex from an electrolyte containing excess ligand have been calculated. It has been shown that the rate of the electrode process is controlled by the diffusion of reduced ions to the electrode surface and by the electron-transfer reaction. The possibility of using iminodiacetate electrolyte for palladium plating for the deposition of fine-crystalline adherent and ductile palladium coatings has been examined.

Valeriy S. Kublanovsky

2013-11-01

400

Investigation of a basic electrolyte for decontamination  

International Nuclear Information System (INIS)

An electrolyte for decontaminating metals in a basic solution (pH greater than 7) was invented. The use of a basic electrolyte simplified recovery problems with respect to radioactive contaminants and anodically dissolved base metals. The electrolyte was used on a lab scale to decontaminate stainless steel which had been exposed to plutonium and americium. Actual glove box samples, as well as artifically contaminated samples, were decontaminated to less than 0.14 disintegrations per square centimeter per minute. Separation of the radioactive species and most of the anodically dissolved materials was accomplished by filtration

 
 
 
 
401

77 FR 25406 - Consortium on “Concrete Rheology: Enabling Metrology (CREME)”: Membership Fee Update  

Science.gov (United States)

...Technology Consortium on ``Concrete Rheology: Enabling Metrology (CREME)'': Membership Fee Update AGENCY: National Institute...NIST/Industry Consortium on Concrete Rheology: Enabling Metrology (CREME)''. The notice stated that membership fees...

2012-04-30

402

Model of ciliary clearance and the role of mucus rheology  

Science.gov (United States)

It has been observed that the transportability of mucus by cilial mats is dependent on the rheological properties of the mucus. Mucus is a non-Newtonian fluid that exhibits a plethora of phenomena such as stress relaxation, tensile stresses, shear thinning, and yielding behavior. These observations motivate the analysis in this paper that considers the first two attributes in order to construct a transport model. The model developed here assumes that the mucus is transported as a rigid body, the metachronal wave exhibits symplectic behavior, that the mucus is thin compared to the metachronal wavelength, and that the effects of individual cilia can be lumped together to impart an average strain to the mucus during contact. This strain invokes a stress in the mucus, whose non-Newtonian rheology creates tensile forces that persist into unsheared regions and allow the unsupported mucus to move as a rigid body whereas a Newtonian fluid would retrograde. This work focuses primarily on the Doi-Edwards model but results are generalized to the Jeffrey's fluid as well. The model predicts that there exists an optimal mucus rheology that maximizes the shear stress imparted to the mucus by the cilia for a given cilia motion. We propose that this is the rheology that the body strives for in order to minimize energy consumption. Predicted optimal rheologies are consistent with results from previous experimental studies when reasonable model parameters are chosen.

Norton, Michael M.; Robinson, Risa J.; Weinstein, Steven J.

2011-01-01

403

Rheological dependence of extension in wedge models of convergent orogens  

Science.gov (United States)

Although several mechanical models of extension in contractional orogens have been proposed, in many cases these models have been based on viscous constitutive laws. Lack of more complicated rheological models has primarily been due to the technical difficulty of solving for deformation with complex rheological behavior and boundary conditions. A finite-element model is presented that allows for solution of the wedge mechanical problem with viscous, non-linear viscous and Coulomb plastic rheologies. This model is used to investigate extension in a doubly-vergent wedge model in which deformation is primarily contractional, driven by a reversal of basal traction. Proposed models showing extension in the crust at shallow crustal levels, in spite of overall contraction and contraction at depth, are confirmed, but only for high Argand number (low crustal viscosity). At low Argand number little or no extension is observed. Non-linear stress dependence (power-law flow) also suppresses extension, but not entirely; some extension is observed at high effective Argand number. However with a Coulomb plastic rheology, no extension is observed for a wide range of parameter values. No extension is observed for models with viscous deformation at depth and plastic deformation near the surface. This suggests that the extension is a function of the rheologic model, not the effective strength of the crust. Coeval extension and contraction in convergent orogens with steady external forcing therefore requires viscous deformation to very shallow depths.

Willett, Sean D.

1999-05-01

404

Modelling surface rheology of complex interfaces with extended irreversible thermodynamics  

Science.gov (United States)

The rheological properties of the interfaces in complex multiphase systems often play a crucial role in the dynamic behavior of these systems. For example, these properties affect the dynamics of emulsions, of dispersions of vesicles, of biological fluids, or of free surface flows. In the past three to four decades a vast amount of literature has been produced dealing with the rheological properties of interfaces stabilized by low molecular weight surfactants, proteins, (bio)polymers, lipids, colloidal particles, and various mixtures of these surface active components. The data of these surface rheological experiments are often analyzed with ad hoc generalizations of rheological models used for the analysis of rheological properties of bulk phases. The validity of these generalizations is in general not discussed. Here we show how the extended irreversible thermodynamics (EIT) formalism can be used to generate a wide range of thermodynamically admissible constitutive models for the surface stress tensor, which not only encompass currently used constitutive models, but also suggest several new ones, particularly useful for modelling the nonlinear response of interfaces.

Sagis, Leonard M. C.

2010-02-01

405

Synthesis and characterization of partially fluorinated poly(acryl) ionomers for polymer electrolyte membrane fuel cells and ESR-spectroscopic investigation of the radically induced degradation of model compounds; Synthese und Charakterisierung teilfluorierter Poly(acryl)-Ionomere als Polymerelektrolytmembranen fuer Brennstoffzellen und ESR-spektroskopische Untersuchung der radikalinduzierten Degradation von Modellverbindungen  

Energy Technology Data Exchange (ETDEWEB)

In the first part of this work different strategies for the design of sulfonated partially fluorinated poly(aryl)s are developed and synthetically realized. The applied concept is that partially fluorinated poly(aryl)s are distinguished from the nonfluorinated ones by an enhanced acidity. Moreover they possess higher bond dissociation energies of both the C-F bonds and any adjacent C-H bonds which should be associated with a gain in radical stability and thus in chemical and thermal stability. In order to investigate the influence of the chemical structure of (partially fluorinated) monomeric building blocks, homo-polymers with different structural units (with aromatic C-F bonds, C(CF3)2-bridged and/or CF3-substituted phenylene rings) are synthesized by polycondensation and structurally characterized (elemental analysis, NMR spectroscopy, gel permeation chromatography). Established organic reactions, such as the Balz-Schiemann reaction, Suzuki reaction and Ullmann's biaryl synthesis, are applied for the synthesis of the specific monomers. After sulfonation of the homo-polymers (ionically crosslinked) membranes are prepared and characterized in terms of suitability as polymer electrolyte membrane in fuel cells (ion-exchange capacity, proton conductivity, thermal and chemical stability, water uptake, dimensional change). Both the chemical nature of the monomers and their constitution in the ionomer are important for the properties of the resulting membranes. Therefore microphase-separated multiblock-co-ionomers based on hydrophilic (sulfonated) and hydrophobic (partially fluorinated) telechelic macromonomers are prepared and characterized. Both the influence of the block length and the chemical nature of the used monomers on the membrane properties are comparatively investigated. On the basis of the findings gained in this part of the work, the advantages and disadvantages of partially fluorinated ionomer membranes are analyzed and discussed. The second part of this work deals with the EPR-spectroscopic investigation of radically induced degradation reactions of model compounds which represent structural units of poly(aryl) ionomers prepared in the first part of this work. These model compounds are exposed to hydroxyl and hydroperoxyl radicals in a flow cell, which are generated directly by photolysis of hydrogen peroxide in the cavity of an ESR spectrometer. By using this experimental setup different parameters (such as concentration of hydroxyl radicals, monomer concentration, flow rate, and pH value) are varied systematically and their influences in terms of the observed product formation of the aromatic model compounds with the hydroxyl radicals are estimated. Conclusions in terms of possible radical reactions of the poly(aryl) ionomer can be drawn from these investigations and information of avoidable structural features (e.g. type of the end groups of the ionomers) and avoidable conditions (e.g. inhomogeneities of pH values in the membrane) are obtained. (orig.)

Schoenberger, Frank

2008-07-09

406

Preparation of lithium indium oxide via a rheological phase route and its electrochemical characteristics in LiOH and Li{sub 2}SO{sub 4} solutions  

Energy Technology Data Exchange (ETDEWEB)

Submicrometer-sized lithium indium oxide (LiInO{sub 2}) powder via a rheological phase method using trilithium citrate tetra hydrate (C{sub 6}H{sub 5}Li{sub 3}O{sub 7} . 4H{sub 2}O) and indium oxide (In{sub 2}O{sub 3}) has been prepared in this work for the first time. The optimal pyrolyzing temperature range to prepare crystalline LiInO{sub 2} is between 650 and 900 C, which was confirmed by thermal gravimetric and differential thermogravimetric analysis of the precursor and X-ray diffraction analysis. The pure phase LiInO{sub 2} sample obtained has a uniform particle morphology and submicrosize, which was observed by scanning electron microscopy. The electrochemical studies show that a new pair of cathodic and anodic peaks at 0.23 and 0.38 V (vs. saturated calomel electrode) was obviously observed from the cyclic voltammetry curve of LiInO{sub 2} in 1 M LiOH solution, indicating a battery characteristic of the material in this electrolyte. While in 1 M Li{sub 2}SO{sub 4} solution, the sample presents a supercapacitive characteristic within the same potential range. The reasons for different electrochemical behaviors in these two electrolytes can be attributed to the fact that the reaction of lithium ion insertion/extraction into/out of a LiInO{sub 2} electrode takes place in the bulk material in LiOH electrolyte solution, whereas it takes place on the electrode/electrolyte interface for Li{sub 2}SO{sub 4} electrolyte case. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Zhang, Guo-Qing [Department of Chemistry and Environment Science of Yangtze Normal University, 408100 Chongqing (China); College of Chemistry and Chemical Engineering of Chongqing University, Chongqing 400030 (China); Zhang, Sheng-Tao [College of Chemistry and Chemical Engineering of Chongqing University, Chongqing 400030 (China); Wu, Xing-Fa [Department of Chemistry and Environment Science of Yangtze Normal University, 408100 Chongqing (China)

2010-01-15

407

Improved Cyclability of Liquid Electrolyte Lithium/Sulfur Batteries by Optimizing Electrolyte/Sulfur Ratio  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A liquid electrolyte lithium/sulfur (Li/S) cell is a liquid electrochemical system. In discharge, sulfur is first reduced to highly soluble Li2S8, which dissolves into the organic electrolyte and serves as the liquid cathode. In solution, lithium polysulfide (PS) undergoes a series of complicated disproportionations, whose chemical equilibriums vary with the PS concentration and affect the cell’s performance. Since the PS concentration relates to a certain electrolyte/sulfur (E/S) r...

Zhang, Sheng S.

2012-01-01

408

Single-ion conducting polymer-silicate nanocomposite electrolytes for lithium battery applications  

International Nuclear Information System (INIS)

Solid-state polymer-silicate nanocomposite electrolytes based on an amorphous polymer poly[(oxyethylene)8 methacrylate], POEM, and lithium montmorillonite clay were fabricated and characterized to investigate the feasibility of their use as 'salt-free' electrolytes in lithium polymer batteries. X-ray scattering and transmission electron microscopy studies indicate the formation of an intercalated morphology in the nanocomposites due to favorable interactions between the polymer matrix and the clay. The morphology of the nanocomposite is intricately linked to the amount of silicate in the system. At low clay contents, dynamic rheological testing verifies that silicate incorporation enhances the mechanical properties of POEM, while impedance spectroscopy shows an improvement in electrical properties. With clay content ?15 wt.%, mechanical properties are further improved but the formation of an apparent superlattice structure correlates with a loss in the electrical properties of the nanocomposite. The use of suitably modified clays in nanocomposites with high clay contents eliminates this superstructure formation, yielding materials with enhanced performance

409

Single-ion conducting polymer-silicate nanocomposite electrolytes for lithium battery applications  

Energy Technology Data Exchange (ETDEWEB)

Solid-state polymer-silicate nanocomposite electrolytes based on an amorphous polymer poly[(oxyethylene){sub 8} methacrylate], POEM, and lithium montmorillonite clay were fabricated and characterized to investigate the feasibility of their use as 'salt-free' electrolytes in lithium polymer batteries. X-ray scattering and transmission electron microscopy studies indicate the formation of an intercalated morphology in the nanocomposites due to favorable interactions between the polymer matrix and the clay. The morphology of the nanocomposite is intricately linked to the amount of silicate in the system. At low clay contents, dynamic rheological testing verifies that silicate incorporation enhances the mechanical properties of POEM, while impedance spectroscopy shows an improvement in electrical properties. With clay content {>=}15 wt.%, mechanical properties are further improved but the formation of an apparent superlattice structure correlates with a loss in the electrical properties of the nanocomposite. The use of suitably modified clays in nanocomposites with high clay contents eliminates this superstructure formation, yielding materials with enhanced performance. (Author)

Kurian, Mary; Galvin, Mary E. [Delaware Univ., Dept. of Materials Science and Engineering, Newark, DE (United States); Trapa, Patrick E.; Sadoway, Donald R.; Mayes, Anne M. [Massachusetts Inst. of Technology, Dept. of Materials Science and Engineering, Cambridge, MA (United States)

2005-03-15

410

Investigation of novel electrolyte systems for advanced metal/air batteries and fuel cells  

Science.gov (United States)

It is a worldwide challenge to develop advanced green power sources for modern portable devices, transportation and stationary power generation. Metal/air batteries and fuel cells clearly stand out in view of their high specific energy, high energy efficiency and environment-friendliness. Advanced metal/air batteries based on metal ion conductors and proton exchange membrane (PEM) fuel cells operated at elevated temperatures (>120°C) can circumvent the limitations of current technologies and bring considerable advantages. The key is to develop suitable electrolytes to enable these new technologies. In this thesis research, investigation of novel electrolytes systems for advanced metal/air batteries and PEM fuel cells is conducted. Novel polymer gel electrolyte systems, [metal salt/ionic liquid/polymer] and [metal salt/liquid polyether/polymer] are prepared. Such systems contain no volatile solvents, conduct metal ions (Li+ or Zn 2+) with high ionic conductivity, possess wide electrochemical stability windows, and exhibit wide operating temperature ranges. They promise to enable non-aqueous, all-solid-state, thin-film Li/air batteries and Zn/air batteries. They are advantageous for application in other battery systems as well, such as rechargeable lithium and lithium ion batteries. In the case of proton exchange membranes, polymer gel electrolyte systems [acid/ionic liquid/polymer] are prepared. Especially, H3PO4/PMIH2PO 4/PBI is demonstrated as prospective proton exchange membranes for PEM fuel cells operating at elevated temperatures. Comprehensive electrochemical characterization, thermal analysis (TGA and DSC) and spectroscopy analysis (NMR and FTIR) are carried out to investigate these novel electrolyte systems and their ion transport mechanisms. The design and synthesis of novel ionic liquids and electrolyte systems based on them for advantageous application in various electrochemical power sources are highlighted in this work.

Ye, Hui

411

Highly Quantitative Electrochemical Characterization of Non-Aqueous Electrolytes & Solid Electrolyte Interphases  

Energy Technology Data Exchange (ETDEWEB)

The methods to measure solid electrolyte interphase (SEI) electrochemical properties and SEI formation capability of non-aqueous electrolyte solutions are not adequately addressed in the literature. And yet, there is a strong demand in new electrolyte generations that promote stabilized SEIs and have an influence to resolve safety, calendar life and other limitations of Li-ion batteries. To fill this gap, in situ electrochemical approach with new descriptive criteria for highly quantitative characterization of SEI and electrolytes is proposed. These criteria are: SEI formation capacity, SEI corrosion rate, SEI maintenance rate, and SEI kinetic stability. These criteria are associated with battery parameters like irreversible capacity, self-discharge, shelf-life, power, etc. Therefore, they are especially useful for electrolyte development and standard fast screening, allowing a skillful approach to narrow down the search for the best electrolyte. The characterization protocol also allows retrieving information on interfacial resistance for SEI layers and the electrochemical window of electrolytes, the other important metrics of characterization. The method validation was done on electrolyte blends containing phosphazenes, developed at Idaho National Laboratory, as 1.2M LiPF6 [80 % EC-MEC (2:8) (v/v) + 20% Phosphazene variety] (v/v), which were ta