WorldWideScience
 
 
1

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

2

Electrolytic Synthesis and Characterizations of Silver Nanopowder  

CERN Multimedia

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

3

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

International Nuclear Information System (INIS)

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

2007-09-02

4

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

5

Synthesis and Rheology of Model Comb Polymer Architectures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For a better understanding of the extent of branching and its influence on the rheological properties of commercial branched polymers, well-defined linear and branched (comb) model polymers were synthesized. The correlation between the melt rheological properties and the polymer topology was investigated under small amplitude oscillatory shear (SAOS), uniaxial extension and medium- (MAOS) respectively large amplitude oscillatory shear (LAOS) in combination with Fourier-Transform rheology.

2012-01-01

6

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

7

Synthesis of metal nanoparticles by electrolytical STM and electrochemical discharges  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As conventional fabrication techniques reach their limits novel techniques are needed for fabrication of structures in the nanometer range. This thesis investigates new methods to create metal nanostructures or nanoparticles with an STM tip or a sharp metal tool working inside an electrolyte. Electrochemical synthesis has the advantage that since deposition/etching are controlled by electrode potentials, it can be relatively simple to control and in addition STM allows in situ observation. Ma...

2007-01-01

8

Synthesis and rheological properties of cation-exchanged Laponite suspensions  

Energy Technology Data Exchange (ETDEWEB)

In this paper we report our new approach to synthesize cation-exchanged Laponite suspensions. General observations of the prepared samples indicated that an aqueous suspension of 1 wt% Laponite retained its free flowing liquid phase characteristics even after aging for several weeks. When bivalent cationic metals (Cu, Co, Ni) were ablated into the suspension, the strong charge of the crystal face was reduced and, on standing, the suspension gelled becoming highly viscous. This sol-gel transition was induced by the formation of a space-filled structure due to both van derWaals and electrostatic bonds between the positively charged rims and negatively charged faces. Rheological properties of such prepared suspensions were measured using a Brookfield DV-H Pro Viscometer with a small sample adapter{SSA18/13RPY). The yield strengths of2.2 N/m2, 3.2 N/m2, and 1.7 N/m2 were measured for Ni-, Co-, and Cu-modified Laponite suspensions, respectively. These yield strengths are sufficiently high for suspending weighting materials such as barite which requires the gel strength of about 0.5 N/m2.

Tran, X.P.; Howard, B.; Chyu, M.K.

2009-01-01

9

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

1988-01-01

10

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)_2·8H_2O 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

1993-01-01

11

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

12

Synthesis of and characterization of lithium ceramic electrolytes  

Science.gov (United States)

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

Rangasamy, Ezhiylmurugan

13

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

14

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

15

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

16

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

17

RHEOLOGICAL PHASE SYNTHESIS AND CHARACTERIZATION OF MICRO-SIZED Li4Ti5O12  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 micr...

LINGLING XIE; XIAOYU CAO; CHANGWEI LIU; CHIWEI WANG

2010-01-01

18

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

Science.gov (United States)

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

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

2013-12-01

19

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

20

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)

2010-11-21

 
 
 
 
21

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

DEFF Research Database (Denmark)

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

Jankova Atanasova, Katja; Hvilsted, Søren

2007-01-01

22

Computational rheology  

CERN Multimedia

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

23

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

International Nuclear Information System (INIS)

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

2007-01-01

24

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

Science.gov (United States)

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

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

2014-07-21

25

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

International Nuclear Information System (INIS)

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

2013-12-15

26

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

International Nuclear Information System (INIS)

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

2008-12-01

27

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

28

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

2000-02-01

29

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

30

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.

2010-01-25

31

SYNTHESIS OF A NEW FAMILY OF FLUORINATED BORONATE COMPOUNDS AS ANION RECEPTORS AND STUDIES OF THEIR USE AS ADDITIVES IN LITHIUM BATTERY ELECTROLYTES.  

Energy Technology Data Exchange (ETDEWEB)

Numerous studies have been done on developing new electrolytes for lithium batteries with high ionic conductivity, and good chemical and electrochemical stability. In addition to the research on new salts and solvents, the use of cation receptors to reduce ion pairing in non-aqueous electrolytes has been considered as an approach to improve the properties of electrolytes. Although both cation and anion receptors enhance the dissociation of ion pairs and increase the conductivity of electrolytes, the use of anion receptors is more attractive for a lithium battery electrolyte because anion receptors increase the lithium transference number in the electrolyte. However, most available neutral anion receptors complex with anions through hydrogen binding and cannot be used in lithium batteries. Recently, we have reported on synthesis of a series of new neutral boron compounds as anion receptors based on the idea that electron-deficient boron would complex the anion of the ion pair. The anion complexation effect of these boron compounds was further enhanced by attaching electron-withdrawing groups. Here we report synthesis of another new family of boronate compounds. The effect of these new compounds on conductivity of lithium salts in non-aqueous solution was studied. The molecular weights of these new boronate compounds are lower than our previously reported boron compounds. Therefore, their effects on conductivity enhancement are superior. They also display high electrochemical stability up to 5 V.

MCBREEN,J.; LEE,H.S.; YANG,X.Q.

2001-06-08

32

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

International Nuclear Information System (INIS)

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

2012-12-30

33

Synthesis of a Lewis-acidic boric acid ester monomer and effect of its addition to electrolyte solutions and polymer gel electrolytes on their ion transport properties  

International Nuclear Information System (INIS)

A polymerizable anion receptor based on a boric acid ester was synthesized. When the anion receptor was added to different electrolyte solutions consisting of an aprotic solvent and a lithium salt, the ionic conductivity of certain electrolyte solutions, composed of low polar solvents or salts with low dissociation abilities, was enhanced appreciably. Viscosity measurements for the electrolyte solutions, with and without the added anion receptor, indicated that the conductivity enhancement was caused by an increase in the ionic dissociation due to the addition of the anion receptor. Pulse-field-gradient spin-echo (PGSE) NMR and 11B-NMR spectra supported that the ionic dissociation was facilitated by interaction between the Lewis-acidic anion receptor and Lewis-basic anions. The polymerizable anion receptor was crosslinked with a polyether macromonomer in different electrolyte solutions. Ionic conductivity of the resulting polymer gel electrolytes was also altered like that of the electrolyte solutions containing the anion receptor monomer

2003-06-30

34

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

35

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

2008-12-01

36

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

37

Synthesis of LiFePO{sub 4}/C cathode materials through an ultrasonic-assisted rheological phase method  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Display Omitted Highlights: > LiFePO{sub 4}/C active material was synthesized using an ultrasonic-assisted rheological phase method. > In addition, polyvinyl butyral (PVB) was added in various concentrations to provide carbon coating on the surface of the LiFePO{sub 4} particles for enhanced electrical conductivity. > The synthesized particle had a size range of 100 {approx} 150 nm and a carbon layer of about 8 nm. > The LiFePO{sub 4}/C (5 wt% PVB) delivered an initial discharge capacity of 167.5 mAh/g at a 0.1 C rate. - Abstract: LiFePO{sub 4}/C active material was synthesized using an ultrasonic-assisted rheological phase method. In addition, polyvinyl butyral (PVB) was added in various concentrations to provide carbon coating on the surface of the LiFePO{sub 4} particles for enhanced electrical conductivity. The crystal structure, morphology, and carbon coating layer of the synthesized LiFePO{sub 4}/C was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The electrochemical performance of LiFePO{sub 4}/C, such as initial capacity, rate capability, cycling performance and EIS, were also evaluated. The synthesized particle had a size range of 100-150 nm and a carbon layer of about 8 nm. The LiFePO{sub 4}/C (5 wt% PVB) delivered an initial discharge capacity of 167.5 mAh/g at a 0.1 C rate. It also showed an excellent capacity retention ratio of 100% after the 50th charging/discharging. EIS results demonstrate that the charge transfer resistance of the sample decreases greatly by coating with 5 wt% PVB.

Kim, Hyun-Ju; Kim, Jeong-Min [Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Kim, Woo-Seong [Daejung EM Co., Incheon 429-450 (Korea, Republic of); Koo, Hoe-Jin [Battery R and D Association of Korea, Seoul 137-894 (Korea, Republic of); Bae, Dong-Sik [Changwon National University, Changwon 641-773 (Korea, Republic of); Kim, Hyun-Soo, E-mail: hskim@keri.re.kr [Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of)

2011-05-05

38

Synthesis of LiFePO4/C cathode materials through an ultrasonic-assisted rheological phase method  

International Nuclear Information System (INIS)

Graphical abstract: Display Omitted Highlights: ? LiFePO4/C active material was synthesized using an ultrasonic-assisted rheological phase method. ? In addition, polyvinyl butyral (PVB) was added in various concentrations to provide carbon coating on the surface of the LiFePO4 particles for enhanced electrical conductivity. ? The synthesized particle had a size range of 100 ? 150 nm and a carbon layer of about 8 nm. ? The LiFePO4/C (5 wt% PVB) delivered an initial discharge capacity of 167.5 mAh/g at a 0.1 C rate. - Abstract: LiFePO4/C active material was synthesized using an ultrasonic-assisted rheological phase method. In addition, polyvinyl butyral (PVB) was added in various concentrations to provide carbon coating on the surface of the LiFePO4 particles for enhanced electrical conductivity. The crystal structure, morphology, and carbon coating layer of the synthesized LiFePO4/C was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The electrochemical performance of LiFePO4/C, such as initial capacity, rate capability, cycling performance and EIS, were also evaluated. The synthesized particle had a size range of 100-150 nm and a carbon layer of about 8 nm. The LiFePO4/C (5 wt% PVB) delivered an initial discharge capacity of 167.5 mAh/g at a 0.1 C rate. It also showed an excellent capacity retention ratio of 100% after the 50th charging/discharging. EIS results demonstrate that the charge transfer resistance of the sample decreases greatly by coating with 5 wt% PVB.

2011-05-05

39

Synthesis and electrochemical performances of di(trimethylolpropane) tetraacrylate-based gel polymer electrolyte  

Science.gov (United States)

The di(trimethylolpropane) tetraacrylate-based gel polymer electrolyte (GPE) was stable electrochemically up to 4.5 V versus Li/Li + and showed the ionic conductivity of 6.2 × 10 -3 S cm -1 at room temperature. Lithium-ion polymer batteries with the GPE were prepared and their performances were also investigated. The battery showed good rate capability and low temperature performance. The cell delivered 95.1% of the initial discharge capacity at 1.0 C rate after the 150th cycling. At the over-charged test, the temperature did not exceed 90 °C and neither leakage of electrolyte nor explosion was observed in the cell.

Kim, Hyun-Soo; Moon, Seong-In

40

Synthesis and investigation of electrolytic sodium-vanadium oxide compounds for lithium battery cathodes: electrolytic bronze ?-Na0.33V2O5  

International Nuclear Information System (INIS)

By the method of electrolysis from vanadyl sulfate electrolytes in the presence of 10-20 g/l of sium ions deposits were prepared, which after high-temperature effect transformed into bronze with monoclinic structure of ?-Na0.33V2O5 composition. The bronze composition and properties were studied by the method of X-ray diffraction and thermal analyses, absorption IR spectroscopy, as well as by electrochemical methods. It is shown that the synthesized electrolytic bronze ?-Na0.33V2O5 features a high specific discharge capacity and efficiency of cycling in propylenecarbonate + dimethoxyethane + 1 M LiClO4 electrolyte

2000-06-01

 
 
 
 
41

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 solutio...

Das, C. K.; Sahoo, S.; Dhibar, S.

2012-01-01

42

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

43

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

International Nuclear Information System (INIS)

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

2011-12-15

44

Synthesis and microstructural characterization of Sr- and Mg-substituted LaGaO3 solid electrolyte  

International Nuclear Information System (INIS)

Sr and Mg substituted LaGaO3 is a solid electrolyte for intermediate temperature solid oxide fuel cell. Phase purity of this material is a concern for the researchers for a long time. In this contribution the secondary phases that are evolved during the synthesis of Sr and Mg doped LaGaO3 are reported. For that purpose, a series of La1-xSr xGa1-yMgyO3-? (LSGM) was prepared by solid state synthesis route. Scanning electron microscopic photographs showed secondary phases namely La4Ga2O9, LaSrGa3O7, LaSrGaO4 along with the parent perovskite LSGM depending upon the amount of dopant. Amount of secondary phases was estimated from the peak positions of room temperature X-ray diffraction. It was observed that for a fixed amount of Mg dopant increasing the amount of Sr content also increased the amount of secondary phases whereas the reverse was found to be true when Sr content was fixed and Mg content was increased. This behaviour was attributed to the increase in solid solubility of Sr in presence of Mg

2007-04-15

45

Synthesis and microstructural characterization of Sr- and Mg-substituted LaGaO{sub 3} solid electrolyte  

Energy Technology Data Exchange (ETDEWEB)

Sr and Mg substituted LaGaO{sub 3} is a solid electrolyte for intermediate temperature solid oxide fuel cell. Phase purity of this material is a concern for the researchers for a long time. In this contribution the secondary phases that are evolved during the synthesis of Sr and Mg doped LaGaO{sub 3} are reported. For that purpose, a series of La{sub 1-x}Sr {sub x}Ga{sub 1-y}Mg{sub y}O{sub 3-{delta}} (LSGM) was prepared by solid state synthesis route. Scanning electron microscopic photographs showed secondary phases namely La{sub 4}Ga{sub 2}O{sub 9}, LaSrGa{sub 3}O{sub 7}, LaSrGaO{sub 4} along with the parent perovskite LSGM depending upon the amount of dopant. Amount of secondary phases was estimated from the peak positions of room temperature X-ray diffraction. It was observed that for a fixed amount of Mg dopant increasing the amount of Sr content also increased the amount of secondary phases whereas the reverse was found to be true when Sr content was fixed and Mg content was increased. This behaviour was attributed to the increase in solid solubility of Sr in presence of Mg.

Datta, Pradyot [Max-Planck-Institut fuer Metallforschung and Institut fuer Nichtmetallische, Anorganische Materialien, Universitaet Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstrasse 3, Stuttgart 70569 (Germany)]. E-mail: pdatta@rediffmail.com; Majewski, Peter [University of South Australia, Ian Wark Research Institute, Mawson Lakes, South Australia 5095 (Australia); Aldinger, Fritz [Max-Planck-Institut fuer Metallforschung and Institut fuer Nichtmetallische, Anorganische Materialien, Universitaet Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstrasse 3, Stuttgart 70569 (Germany)

2007-04-15

46

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

47

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

48

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

Science.gov (United States)

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

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

2011-01-01

49

Synthesis of supramolecular solid polymer electrolytes via self-assembly of diborylated ionic liquid  

Energy Technology Data Exchange (ETDEWEB)

Novel supramolecular type solid polymer electrolytes were prepared by self-assembly of diborylated ionic liquid in the presence of bifunctional ligands. The polymers obtained were well soluble in methanol, and their structures were supported by {sup 1}H and {sup 11}B NMR spectra. The ionic conductivity of the polymers was evaluated by ac-impedance method after the samples were dried thoroughly. The ionic conductivity observed was 8.8 x 10{sup -6} to 5.4 x 10{sup -6} S cm{sup -1} at 51 C in the presence of equimolar amount of LiTFSA to ionic liquid unit. The temperature dependence of ionic conductivity was successfully fitted to VFT (Vogel-Fulcher-Tamman) plots, indicating that ionic conduction is taking place according to typical ion transport model in viscous matrix. (author)

Matsumi, Noriyoshi; Kagata, Akihito; Aoi, Keigo [Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

2010-09-15

50

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

International Nuclear Information System (INIS)

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

2008-12-01

51

Synthesis and characterization of sulfonic acid containing polyimides for polymer electrolyte membranes (PEMs) in fuel cells  

Science.gov (United States)

Different polyimides bearing sulfonic acid groups were prepared for polymer electrolyte membranes (PEMs) in fuel cells. These polymers contained displacing, angled, multi-functional and/or fluorinated comonomers. Displacing and angled comonomers produce imperfections in the long rigid liquid crystalline polyimide backbone, generating nanoscale pores lined with sulfonic acid groups. Such pores absorb water strongly even at relatively low humidity, resulting in higher proton conductivity than NafionRTM . However, those copolyimides either dissolve or fragment easily in water at elevated temperatures. To overcome this drawback, a fluorinated comonomer was introduced into the polymer. Long-term stability of the polyimides was evaluated for the PEMs. We observed that the sulfonic acid containing polyimides degraded slowly under ambient conditions, and severely at high temperatures. This was analyzed using FT-IR and viscosity measurements.

Kim, Hyoung-Juhn

52

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

Science.gov (United States)

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

Ishrat, Urfi; Rafiuddin

2013-10-01

53

Advances in rheology  

Energy Technology Data Exchange (ETDEWEB)

Over 380 papers are presented collected in four volumes: Theory, Fluids, Polymers, and Applications. The papers are further divided into sections on: general theory, numerical analysis, fluids, suspensions, solids, melts, polymer processing, composites, rheometry, bio-rheology, food rheology, and petroleum rheology. All relevant papers have been abstracted separately.

Mena, B.; Garcia-Rejon, A.; Rangel-Nafaile, C. (eds.)

1984-01-01

54

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

Energy Technology Data Exchange (ETDEWEB)

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

Shetty, Amitha; Nanda, Karuna Kar [Indian Institute of Science, Materials Research Centre, Bangalore (India)

2012-10-15

55

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

International Nuclear Information System (INIS)

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

2006-04-13

56

Synthesis and characterization of Nafion-stabilized Pt nanoparticles for polymer electrolyte fuel cells  

Energy Technology Data Exchange (ETDEWEB)

Platinum nanoparticles are synthesized by alcohol reduction method using Nafion as a stabilizer under various conditions such as the Nafion/Pt molar ratio and reflux temperature. Nafion-Pt nanoparticles are characterized by agglomeration and the particle size is typically in the range of 2-4nm. The electrocatalytic activity of Nafion-Pt nanoparticles for polymer electrolyte and direct methanol fuel cells (PEFCs and DMFCs) is investigated in comparison to that of unsupported Pt black and carbon-supported Pt/C electrocatalysts. Nafion-Pt nanoparticles prepared with low Nafion/Pt ratios show higher and/or comparable activities towards O{sub 2} reduction reaction in the absence and presence of methanol in comparison to that of Pt black and Pt/C electrocatalysts. In contrast, the electrocatalytic activity of the Nafion-Pt nanoparticles for the methanol oxidation reaction is very low. The results indicate that Pt nanoparticles embedded in Nafion polyelectrolyte are potential methanol tolerant electrocatalysts for the O{sub 2} reduction reaction in DMFCs. (author)

Liu, Zengcai; Tian, Zhi Qun; Jiang, San Ping [Nanyang Technological University, (Singapore). School of Mechanical and Aerospace Engineering

2006-11-12

57

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-12-01

58

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

International Nuclear Information System (INIS)

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

2010-12-01

59

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

60

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

 
 
 
 
61

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

International Nuclear Information System (INIS)

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

2008-12-01

62

Nickel electrocrystallization in different electrolytes: An in-process and post synthesis analysis  

International Nuclear Information System (INIS)

The present report is solicited for contributions of nucleation–growth mechanisms of electrodeposition of nickel in different aqueous solutions. The cyclic voltammetry (CV) analysis has been performed on electrocrystallized Ni to understand the deposition and dissolution processes in four types of baths i.e. sulphate, chloride, Watts and sulphamate baths. The result shows that for chloride and sulphate bath there are distinct peaks but for Watts and sulphamate there is no such cathodic peaks, rather it increased to the specified vertex potential. And also it is observed that for sulphate bath the dissolution peak is observed but the physical observation of the electrode after the completion of CV depicts that dissolution takes place partially. The in-process and post synthesis analysis was studied by electrochemical techniques followed by morphological studies (by scanning electron microscope (SEM) and atomic force microscope (AFM)). The other technique used in this study includes XRD to analyze the phase, crystallite size and lattice strain, surface profilometer and Nanoindenter to analyze the structure and properties of deposits (residual stress and hardness). The thickness of the film varies from 1.3 to 2.7 ?m for baths from sulphate, sulphamate, Watts to chloride baths. The compressive stress obtained for different baths vary from 4.015 to 11.231 GPa and tensile stress vary from 3.778 to 16.608 GPa from sulphamate, Watts, sulphate to chloride baths. Also the stress reduces and hardness increases from sulphamate, Watts, sulphate to chloride baths. The grain size decreases and lattice strain increases from sulphamate, Watts, sulphate to chloride baths

2013-05-30

63

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

International Nuclear Information System (INIS)

The present work is part of a program to develop ionically conducting materials for potential use in energy storage and conversion systems. With applications in high energy-density batteries, magneto-hydrodynamic (MHD) generators, fuel cells and sensors, they ae playing an increasinly important role in developing more efficient energy storage and conversion devices. Using a wet-chemical procedure, a series of compostions having between 0 and 22.2 mol percent CaO in zirconia, was prepared and subsequently formed into sintered samples having a relative density from 95 to 98 percent. Sintered samples were prepared of each composition with a geometry appropriate for determining the thermal, electrical or microstructural characteristics. This report covers only the microstructural aspects of powder synthesis and the development of sintered materials. Using the reactive, homogeneous, chemically prepared powders, it has been shown that cubic and monoclinic zirconia can coexist in compositions containing up to 10 mol percent CaO. From 10 to 20 mol percent CaO, only the cubic phase is formed, whereas at higher CaO concentrations the cubic phase coexits with CaZro3. The change from a two-phase to single-phase system as the CaO concentration is increased above 10 mol percent, increases the grain size nearly an order of magnitude. It has been found that 5 and 7.6 mol percent CaO materials develop considerable stress during the cooling stage of the firing cycle. As a result, they undergo a progressive and irreversible expansion with each thermal shock cycle: the magnitude of the expansion is proportional to the severity of the thermal shock. The microstructural texture of these partially stablilized materials was also shown to be dependent on the thermal history and hence a strong dependence of the electrical and thermal properties can be anticipated. (auth)

1978-01-01

64

Electrolytes Test  

Science.gov (United States)

... of this website will be limited. Search Help? Electrolytes Share this page: Was this page helpful? Also known as: Lytes Formal name: Electrolyte Panel Related tests: Sodium , Potassium , Chloride , Bicarbonate , Comprehensive ...

65

Linear and nonlinear rheology of wormlike micelles  

CERN Document Server

Several surfactant molecules self-assemble in solution to form long, cylindrical, flexible wormlike micelles. These micelles can be entangled with each other leading to viscoelastic phases. The rheological properties of such phases are very interesting and have been the subject of a large number of experimental and theoretical studies in recent years. We shall report on our recent work on the macrorheology, microrheology and nonlinear flow behaviour of dilute aqueous solutions of a surfactant CTAT (Cetyltrimethylammonium Tosilate). This system forms elongated micelles and exhibits strong viscoelasticity at low concentrations ($\\sim$ 0.9 wt%) without the addition of electrolytes. Microrheology measurements of $G(\\omega)$ have been done using diffusing wave spectroscopy which will be compared with the conventional frequency sweep measurements done using a cone and plate rheometer. The second part of the paper deals with the nonlinear rheology where the measured shear stress $\\sigma$ is a nonmonotonic function o...

Sood, A K; Basappa, G; Basappa, Geetha

1999-01-01

66

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.

2011-02-01

67

Properties of Sulfolane Based Aprotic Electrolytes  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english The article deals with description of rheological and electrical properties of solvents for electrolytes of lithium-ion batteries. Solvents mixture of dimethyl sulfone and sulfolane at different volume ratios and with a lithium salt (LiClO4) appears as a potentially suitable electrolyte. In this wor [...] k, we investigate the influence of different solvents and their mixtures in order to find a solvent which increases the fire safety of such battery. The aim of this experiment is to investigate the rheological properties, particularly density and dynamic viscosity of solvents with lithium salt in temperature dependence and to find the optimal composition of the electrolyte from the perspective of achieving the lowest dynamic viscosity and better electrical conductivity, because both quantities are closely related with Walden's rule. The vibration method is used to determine the values of dynamic viscosity.

Josef, Maca; Martin, Frk; Zdenka, Rozsivalova; Marie, Sedlarikova.

2013-11-11

68

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-15

69

Synthesis and characterization of polyvinyl alcohol copolymer/phosphomolybdic acid-based crosslinked composite polymer electrolyte membranes  

Energy Technology Data Exchange (ETDEWEB)

Polymer electrolyte membrane fuel cells (PEMFCs) are very promising as future energy source due to their high-energy conversion efficiency and will help to solve the environmental concerns of energy production. Polymer electrolyte membrane (PEM) is recognised as the key element for an efficient PEMFC. Chemically crosslinked composite membranes consisting of a poly(vinyl alcohol-co-vinyl acetate-co-itaconic acid) (PVACO) and phosphomolybdic acid (PMA) have been prepared by solution casting and evaluated as proton conducting polymer electrolytes. The proton conductivity of the membranes is investigated as a function of PMA composition, crosslinking density and temperature. The membranes have also been characterized by FTIR spectroscopy, TGA, AFM and TEM. The proton conductivity of the composite membranes is of the order of 10{sup -3} S cm{sup -1} and shows better resistance to methanol permeability than Nafion 117 under similar measurement conditions. (author)

Anis, Arfat; Banthia, A.K. [Materials Science Centre, Indian Institute of Technology, Kharagpur (India); Bandyopadhyay, S. [School of Materials Science and Engineering, University of New South Wales, Sydney (Australia)

2008-04-15

70

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

International Nuclear Information System (INIS)

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

2012-08-15

71

Rheology of waxy oils  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-01

72

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

73

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

International Nuclear Information System (INIS)

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

2011-10-01

74

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-10-01

75

Chocolate rheology Reologia de chocolate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2010-01-01

76

Effects of chemical synthesis parameters on the Zr O2: 8% mol Mg O solid electrolytes electric conductivity and microstructure  

International Nuclear Information System (INIS)

Electrical conductivity measurements and scanning electron microscope observations have been done in Zr O2 - 8 mol % Mg O solid electrolytes. The main purpose was to investigate to what extent some processing variables can influence the electrical behaviour and microstructural characteristics of the sintered ceramic. Zirconia powders have been prepared under different pH and temperature of precipitation, and washing media conditions. The results show that many structural characteristics of the calcined powders are 'lost' during sintering, giving rise to ceramics with similar electrical properties, besides minor differences in the final microstructure. The washing media play the major role on both microstructural development and electrical conductivity. (author)

1996-12-08

77

Rheological Properties of Iron Oxide Based Ferrofluids  

Science.gov (United States)

In the present work, we report synthesis and magneto-viscous properties of cationic and anionic surfactant coated, iron oxide nanoparticles based ferrofluids. Structural and morphological aspects are revealed by x-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. We compare the rheological/magneto-viscous properties of different ferrofluids for various shear rates (2-450 sec-1) and applied magnetic fields (0-100 gauss). In the absence of a magnetic field, and under no shear case, the ferrofluid prepared with TMAH coated particle is found to be 12% more viscous compared to its counterpart. The rheological properties are governed by non-Newtonian features, and for a definite shear rate, viscosity of a given ferrofluid is found to be strongly dependent on the applied magnetic field as well as nature of the surfactant.

Devi, M.; Mohanta, D.

2009-06-01

78

Synthesis and Compatibility of Ionic Liquid Containing Rod-Coil Polyimide Gel Electrolytes with Lithium Metal Electrodes  

Science.gov (United States)

A highly cross-linked polyimide-polyethylene oxide copolymer has been synthesized that is capable of holding large volumes of liquid component, simultaneously maintaining good dimensional stability. An amine end capped oligomer was made that was imidized in solution, followed by reaction with a triisocyanate in the presence of desired additives at ambient temperature. Polymer films are able to hold over 4 times their weight in room temperature ionic liquid RTIL or carbonate solvent. Electrolytes were studied that contained varying amounts of RTIL, lithium trifluoromethanesulfonimide LiTFSi, and alumina nanoparticles. Electrochemical stability of these electrolytes with lithium metal electrodes was studied by galvanic cycling and impedance spectroscopy. Improved cycling stability and decreased interfacial resistance were observed when increasing amounts of RTIL and LiTFSi were added. The addition of small amounts of alumina further decreased interfacial resistance by nearly an order of magnitude. During the course of the study, cycling stability increased from less than 3 to greater than 1000 h at 60 C and 0.25 mA/cm2 current density.

Tigelaar, Dean M.; Palker, Allyson E.; Meador, Mary Ann B.; Bennett, William R.

2008-01-01

79

Solid Electrolyte Materials for use in Lithium-water Primary Batteries And the Synthesis and Characterization of Lanthanide Orthoferrite Magnetic Nanomaterials  

Science.gov (United States)

This thesis was developed in two parts with the overall goals of this work being (1) synthesize and develop solid electrolyte materials for use in a lithium-water battery and (2) synthesize and characterize ternary magnetic nanomaterials. Lithium metal in combination with water is a highly attractive power source due to its high specific energy. Because of the vigorous nature of the reaction between lithium and water, many obstacles must be overcome in order to harness the energy that this system is capable of producing. Parasitic reactions must be controlled so as not to passivate the lithium or consume it totally. In addition, production of hydrogen gas that accompanies both the electrochemical and parasitic reactions can present a serious challenge. As a result it is difficult to maintain high voltage and control the current density in these systems. In order to overcome these obstacles we have developed composite membranes of various lithium-ion conducting solid electrolytes and polymers. Lithium-ion conducting solid electrolytes are known to achieve ionic conductance as high as 10-3 S/cm2. Utilizing these materials in conjunction with polymers, we have created hydrophobic membranes that allow us to limit the parasitic reactions and maintain low cell impedance. Lanthanide orthoferrite materials are technologically important classes of magnetic materials. They have found application in magneto-optical devices as well as in magnetic recording devices. We have explored the syntheses and magnetic properties of nanocrystalline materials. The synthesis of the nanomaterials was done by co-reduction of lanthanide, Ln3+, and iron, Fe 3+, cations with alkalide solution producing the Ln-Fe alloy of the desired stoichiometry. Removal of the byproducts and oxidization of the alloy was accomplished by washing the product with aerated water. Presented herein, several nanoscale lanthanide orthoferrite materials (LnFeO3, Ln = Gd, Tb, Er, Tm, Sm, Dy, Ho, and La) have been prepared. The products have been characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and magnetic properties characterized by use of a Superconducting Quantum Interference Device (SQUID).

Cook, Clifford Corlin

80

Bi13-xMexMo5-yMe’yO34±? –based, Me, Me’ = IIA group and an iron triad metals, new electrolytic materials: synthesis, structure, properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research is devoted to the synthesis, structure, properties of substituted bismuth molybdates which have formulas Bi13-xMexMo5-yMe’yO34±?, Me,Me’== IIA metals of IIA group and an iron triad and show unique structure. The purposes of this research are development of methods of synthesis BiO-based complex oxides materials in Bi-Mo – O system, understanding the mechanism of formation of electrolytic properties of materials, and testing their electroconductive and catalytic propertie...

2013-01-01

 
 
 
 
81

Rock and soil rheology  

International Nuclear Information System (INIS)

The aim of the Euromech Colloquium 196 devoted to Rock and Soil Rheology is to review some of the main results obtained in the last years in this field of research and also to formulate some of the major not yet solved problems which are now under consideration. Exchange of opinions and scientific discussions are quite helpful mainly in those areas where some approaches are controversial and the progress made is quite fast. That is especially true for the rheology of geomaterials, domain of great interest for mining and petroleum engineers, engineering geology, seismology, geophysics, civil engineering, nuclear and industrial waste storage, geothermal energy storage, caverns for sports, culture, telecommunications, storage of goods and foodstuffs (cold, hot and refrigerated storages), underground oil and natural gas reservoirs etc. Some of the last obtained results are mentioned in the present volume. (orig./HP)

1985-09-10

82

[Rheological determinants of end-organ damage].  

Science.gov (United States)

Various studies demonstrated an interdependence between rheological parameters and advanced stages not only of ischaemic heart disease and peripheral arterial occlusive disease, but also of chronic obstructive lung disease. In ischaemic heart disease, rheological alterations in the poststenotic circulation can result in impairment of the oxygen supply of the myocardium. Rheological therapies aim for a reduction in plasma viscosity and improved microcirculatory flow by means of a reduction of the elevated levels of fibrinogen. As an example, intermittent therapy with urokinase has been established as a treatment of refractory angina pectoris. Treatment with fibrates also can result in an improvement of microcirculation due to reduced hepatic fibrinogen synthesis. Treatment with statins leads to an improvement of microcirculation due to effects on serum lipids. In patients with chronic obstructive lung disease and cor pulmonale who, secondary to chronic hypoxia, develop polycythaemia and disturbances in pulmonary microcirculation, isovolumic haemodilution may result in a reduction of pulmonary arterial pressure with consecutively increased cardiac output and improved exercise capacity. PMID:14631581

Leschke, M; Klimek, W; Jung, F

2003-07-01

83

Synthesis of Na-?''-Al2O3 electrolytes by microwave sintering precursors derived from the sol-gel method  

International Nuclear Information System (INIS)

Na-?''-Al2O3 electrolytes were synthesized by the microwave sintering assisted sol-gel technique in this study. The precursor powders and microwave-sintered pellets were systematically investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (TG-DSC) and Fourier transform infrared (FT-IR) spectroscopy. The ionic conductivity of the microwave-sintered pellets was also measured based on AC impedance spectroscopy. It was found that the calcining temperature of the precursor powders derived from the sol-gel method was the key factor to affect the purity of Na-?''-Al2O3 in the pellets. The sintered pellets prepared from the powders calcined at 850 oC exhibited a purity of 94.4% Na-?''-Al2O3 and the density of the sintered pellets was 98.91% of the theoretical density of Na-?''-Al2O3. In addition, the sample showed an ionic conductivity of 0.01085 S cm-1 at 300 oC by AC impedance measurement.

2010-05-14

84

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

Science.gov (United States)

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

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

2010-11-01

85

Electrolyte Racers  

Science.gov (United States)

A fast way to teach investigative skills in science is to tie them to NASCAR using Hot Wheels Formula Fuelers Race Cars. These inexpensive toy cars travel different distances based on the strength of the "electrolyte" (a substance that conducts electricity when dissolved in water) in their "fuel" tanks. Advertisements for these race cars urge kids…

Kellie, Shawn; Kellie, Tonya; Corbin-Tipton, Elizabeth

2006-01-01

86

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)

1975-01-01

87

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

88

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)

2006-01-01

89

Rheology of capsule suspension  

Science.gov (United States)

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

Bagchi, Prosenjit; Murthy Kalluri, R.

2010-11-01

90

Electrolyte salts for nonaqueous electrolytes  

Science.gov (United States)

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

Amine, Khalil; Zhang, Zhengcheng; Chen, Zonghai

2012-10-09

91

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

92

Rheology of Tetraphenylborate Precipitate Slurry.  

Science.gov (United States)

The rheological properties of tetraphenylborate precipitate slurry were determined. This nonradioactive slurry simulates the radioactive tetraphenylborate precipitate generated at the Savannah River Plant by the In-Tank Precipitation Process. The data obt...

I. D. Goren H. D. Martin M. A. McLain

1985-01-01

93

Rheological properties of polypropylene nanocomposites  

International Nuclear Information System (INIS)

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

2009-10-13

94

Synthesis of a New Family of Fluorinated Boronate Compounds as Anion Receptors and Studies of Their Use as Additives in Lithium Battery Electrolytes.  

Science.gov (United States)

Numerous studies have been done on developing new electrolytes for lithium batteries with high ionic conductivity, and good chemical and electrochemical stability. In addition to the research on new salts and solvents, the use of cation receptors to reduc...

J. McBreen H. S. Lee X. Q. Yang

2001-01-01

95

Rheological measurements on cement grouts  

International Nuclear Information System (INIS)

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

1986-01-01

96

Rheological characterization of aged asphalts  

International Nuclear Information System (INIS)

The present work shows the rheological properties of the three Colombian asphalts produced in the refineries at Barrancabermeja, Cartagena and Apiay, exposed to the open air during 18 months using a specially designed testing bank. rheological behavior was evaluated using the new specifications of SHRP technology in the Brookfield and DSR rheometers to determine viscosity, shear stress, shear rate, dynamic share modulus and other related variables. The measurements were made using different temperatures and load times

2002-01-01

97

RHEOLOGICAL INTERPRETATION OF RAYLEIGH DAMPING  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Damping is defined through various terms such as energy loss per cycle (for cyclic tests), logarithmic decrement (for vibration tests), complex modulus, rise-time or spectrum ratio (for wave propagation analysis), etc. For numerical modeling purposes, another type of damping is frequently used : it is called Rayleigh damping. It is a very convenient way of accounting for damping in numerical models, although the physical or rheological meaning of this approach is not clear. A rheological mode...

Semblat, Jean-franc?ois

1997-01-01

98

RHEOLOGICAL CHARACTERIZATION OF AGED ASPHALTS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present work shows the rheological properties of the three Colombian asphalts produced in the refineries at Barrancabermeja, Cartagena and Apiay, exposed to the open air during 18 months using a specially designed testing bank. Rheological behavior was evaluated using the new specifications of SHRP technology in the Brookfield and DSR rheometers to determine viscosity, Shear Stress, Shear Rate, Dynamic Share Modulus and other related variables. The measurements were made using different t...

Natalia Afanasieva; Mario Álvarez; Ortiz, Mo?nica J.

2002-01-01

99

Rheology of magnesite  

Science.gov (United States)

Magnesite (MgCO3) may be incorporated in the mantle either by the subduction of weathered oceanic crust or by reaction of lithospheric mantle with CO2, and it is commonly found within serpentinized peridotite bodies. Once magnesite is formed in subducting slabs, it is likely to remain as an important carbon-bearing phase, given that its stability extends to conditions of the mantle transition zone and possibly the lower mantle. Magnesite is a common mineral in kimberlites and it has been found as inclusions in diamonds, trapped at transition zone pressures. Our experimental results suggest that occurrences of magnesite in the mantle will lead to low strength and anomalous mantle rheology. In order to quantify the rheology of polycrystalline magnesite, we performed a series of triaxial compression experiments on cylinders of natural fine- (d~1 ?m) and coarse-grained (d~100 ?m) magnesite aggregates at temperatures of 400-1000°C and strain rates of 10-4/s - 10-7/s, at effective pressures of 300 and 900 MPa. Flow strengths of the fine-grained magnesite are only weakly dependent on temperature from 400 to 600°C at 1*10-5/s and decrease significantly at greater temperature, from 500 MPa (at T = 600°C) to 5 MPa (at T = 775°C). Strain rate stepping experiments performed at 650 to 750°C indicate that creep of the fine-grained magnesite in the strongly temperature dependent regime is nearly linear-viscous. Flow strengths of the coarse-grained magnesite are weakly dependent on temperature from 400 to 600°C at 1*10-5/s, gradually increase in temperature dependence from 600°C to 800°C, and become strongly temperature dependent from 800 to 1000°C (strengths decrease from 230 MPa to 30 MPa over this range). Strain rate stepping experiments performed at 500°C and 950°C indicate that the strain rate sensitivity of the strength of coarse-grained magnesite increases as the temperature sensitivity increases. The mechanical data of experiments on fine- and coarse-grained magnesite constrain the rheologies in three distinct deformation regimes governed by the predominant deformation mechanisms: 1) limited plasticity mechanisms (twinning and dislocation glide) that operate at low temperatures or high strain rates, 2) dislocation creep of coarse-grained magnesite deformed at high temperatures, and 3) diffusion creep of fine-grained magnesite deformed at high temperatures. The strength of magnesite is intermediate between those of dolomite (CaMg(CO3)2) and calcite (CaCO3), until high temperatures where magnesite becomes weaker than calcite. Magnesite is weaker than olivine at all temperatures. These results indicate that magnesite may play a significant role as a weak phase that could cause strain localization in subducting slabs.

Holyoke, C. W.; Kronenberg, A. K.; Newman, J.; Ulrich, C. A.

2012-12-01

100

Solid state electrolyte systems  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-12-01

 
 
 
 
101

Rheology of foam  

Energy Technology Data Exchange (ETDEWEB)

Both experimental and theoretical analyses were carried out on the rheological behavior of foam. This foam was generated by simultaneously injecting compressed air and an aqueous solution of a commercial foaming agent into a short porous medium. It then flowed into a capillary tube viscometer having 4 interchangeable glass tubes of different radii. A mathematical analysis was developed whereby both the very pronounced effects of fluid slippage at the tube wall and the foam compressibility were taken into consideration. The apparent viscosity was independent of foam quality, but not of tube radius. Bubble size and bubble size distribution were measured under a microscope and the change of bubble size with time studied through photomicrographs. Both the mean bubble diameter and bubble size distribution were functions of foam quality. The cumulative size distribution as a function of a quality is represented by a modified Weibull function. Although the flowing foam behaved like a pseudoplastic fluid, the static foam had a measureable gel strength which increased with foam quality. (18 refs.)

David, A.; Marsden, S.S. Jr.

1969-01-01

102

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

103

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

1994-11-13

104

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

105

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

106

The Deflocculation of Kaolin Suspensions – the Effect of Various Electrolytes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The deflocculation effect of conventional additives to kaolin suspensions is evaluated from the results standard rheological measurements. Several widely used electrolytes (NaOH, Na2CO3, Na2SiO3, SHMP = sodium hexametaphosphate, and CMC = sodium salts of carboxymethylcellulose) have been tested. The optimal concentrations of these deffloculants, in respect to reaching the maximum reduction of initial suspension viscosity, are found. The stability of deflocculated kaolin suspensions against...

2013-01-01

107

Design of magneto-rheological (MR) valve  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magneto-Rheological Fluid (“MRF”) technology has been successfully employed in various low and high volume automotive applications. Good understanding of specific design constraints is required to define and to optimize a magneto-rheological device. This article presents parametrical analyses with magnetic simulations, of a magneto-rheological valve and a magneto-rheological orifice. Experimental rig assemblies of two different control devices have been designed, built and the performance...

Grunwald, Artur; Olabi, Abdul-ghani

2008-01-01

108

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

109

Rheology of hemipelagic marine sediment  

Science.gov (United States)

The mobility and capacity of sediment-laden mass flows are influenced by the rheology of the mixture of water and particles. In order to develop a better understanding of the mechanics that drive these flows we measured the rheology of hemipelagic marine sediment. Using a cone-and-plate rheometer we applied a range of shear strain-rates and measured the shear stress at increasing water contents. We fit the measured shear stresses and shear strain-rates with a Herschel-Bulkley model to determine yield stress and consistency, from which we can find viscosity. By measuring the rheology at incremental increases in water we were are able to determine viscosity and yield stress as a function of particle concentration.

Knappe, E.; Manga, M.

2013-12-01

110

Synthesis and rheology of thermoreversible polyurethane hydrogels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polyurethanes based on poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer, succinic or citric acid, and ethyl ester L-lysine diisocyanate were synthesized and characterized by FT-IR and GPC. Wetting properties were evaluated by contact angle determinations. The critical micelle concentration was determined from surface tension measurements. Their abillity to undergo self-aggregation and temperature induced gelation was investigated through dynamic oscillatory m...

2012-01-01

111

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)

2010-01-01

112

Charge relaxation dynamics of an electrolytic nanocapacitor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 v...

Thakore, Vaibhav; Hickman, James J.

2013-01-01

113

Applied Rheology for Polymer Modification  

Science.gov (United States)

EPDM and EPM were modified using different processing conditions and amounts of peroxide. Rheological measurements were performed in other to characterize and follow the reactions that took place during processing (branching/crosslinking and/or degradation). The experimental results evidenced that branching/crosslinking occurs for EPDM and degradation is the main reaction for EPM.

Machado, Ana Vera; Antunes, Carla Filipa; van Duin, Martin

2009-07-01

114

Fluid and Electrolyte Balance  

Science.gov (United States)

Electrolytes are minerals in your body that have an electric charge. They are in your blood, urine and body fluids. Maintaining the right balance of electrolytes helps your body's blood chemistry, muscle action and ...

115

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Organic–inorganic hybrid electrolyte membranes based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) complexed with LiClO4 via the co-condensation of tetraethoxysilane (TEOS) and 3-(triethoxysilyl)propyl isocyanate have been prepared and characterized. A variety of techniques such as differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrosco...

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

2012-01-01

116

Solid electrolyte photocell  

Energy Technology Data Exchange (ETDEWEB)

A photocell comprising a solid electrolyte film or layer and a pair of electrodes sandwiching therebetween the electrolyte film. The solid electrolyte is AgBr, AgI and silver halide-containing double salts and mixed salts. One of the electrodes is optically transparent and the other electrode is made of a material capable of forming a charge transfer complex with the halogen generated on photodissociation of the electrolyte.

Sekido, S.; Sotomura, T.

1983-06-14

117

Solid polymer electrolyte compositions  

Energy Technology Data Exchange (ETDEWEB)

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

118

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

119

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

120

Rheological Interpretation of Rayleigh Damping  

CERN Document Server

Damping is defined through various terms such as energy loss per cycle (for cyclic tests), logarithmic decrement (for vibration tests), complex modulus, rise-time or spectrum ratio (for wave propagation analysis), etc. For numerical modeling purposes, another type of damping is frequently used : it is called Rayleigh damping. It is a very convenient way of accounting for damping in numerical models, although the physical or rheological meaning of this approach is not clear. A rheological model is proposed to be related to classical Rayleigh damping : it is a generalized Maxwell model with three parameters. For moderate damping (<25%), this model perfectly coincide with Rayleigh damping approach since internal friction has the same expression in both cases and dispersive phenomena are negligible. This is illustrated by finite element (Rayleigh damping) and analytical (generalized Maxwell model) results in a simple one-dimensional case.

Semblat, Jean-François

2009-01-01

 
 
 
 
121

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

122

Aggregate of nanoparticles: rheological and mechanical properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The understanding of the rheological and mechanical properties of nanoparticle aggregates is important for the application of nanofillers in nanocompoistes. In this work, we report a rheological study on the rheological and mechanical properties of nano-silica agglomerates in the form of gel network mainly constructed by hydrogen bonds. The elastic model for rubber is modified to analyze the elastic behavior of the agglomerates. By this modified elastic model, the size of the network mesh can...

Wang, Yu; Wu, Xiaojun; Yang, Wei; Zhai, Yuanming; Xie, Banghu; Yang, Mingbo

2011-01-01

123

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...

2013-01-01

124

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

125

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

Directory of Open Access Journals (Sweden)

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

Hsien-Ming Kao

2012-06-01

126

Evolution of induced structure and rheology of electro-rheological immiscible polymeric blends.  

Czech Academy of Sciences Publication Activity Database

. Vol. 2. Glasgow : Universities design and print unit, 2000, s. 108-110.[International Congress on Rheology /13./. Cambridge (GB), 31.08.2000-01.09.2000]Grant CEP: GA AV ?R KSK1076602; GA AV ?R IAA2060703Klí?ová slova: electro-rheological effect, polymer blend, maxwell-like rheological equationKód oboru RIV: BK - Mechanika tekutin

?íha, Pavel; Takimoto, J.; Masubuchi, Y.; Vlasák, Pavel; Koyama, K.

127

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

128

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

129

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

130

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.

131

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

132

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

133

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

134

Hydrogen selenide treatment of electrolytes  

Energy Technology Data Exchange (ETDEWEB)

A method for lowering the activation energy of a polycrystalline ceramic electrolyte is disclosed. Polycrystalline ceramic electrolytes, such as beta-alumina, when contacted with hydrogen selenide exhibit a lower activation energy than untreated electrolytes.

Rasmussen, J. R.; Virkar, A. V.

1985-01-29

135

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

136

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

2014-07-01

137

Microgravity Foam Structure and Rheology  

Science.gov (United States)

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

Durian, Douglas J.

1997-01-01

138

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

139

RHEOLOGICAL CHARACTERIZATION OF AGED ASPHALTS  

Directory of Open Access Journals (Sweden)

Full Text Available The present work shows the rheological properties of the three Colombian asphalts produced in the refineries at Barrancabermeja, Cartagena and Apiay, exposed to the open air during 18 months using a specially designed testing bank. Rheological behavior was evaluated using the new specifications of SHRP technology in the Brookfield and DSR rheometers to determine viscosity, Shear Stress, Shear Rate, Dynamic Share Modulus and other related variables. The measurements were made using different temperatures and load times.En el presente trabajo se estudian las propiedades reológicas de los tres tipos de asfaltos industriales producidos en Colombia, en las refinerías de Barrancabermeja, Cartagena y Apiay, después del envejecimiento durante 18 meses en un banco de pruebas al aire libre especialmente diseñado. La evaluación del comportamiento reológico se realizó a través de ensayos basados en las nuevas especificaciones de la tecnología SHRP en los reómetros Brookfield y DSR para determinar características tales como: viscosidad, esfuerzo de corte, susceptibilidad térmica, velocidad de deformación y módulo de corte dinámico, a diferentes temperaturas y tiempos de carga.

Natalia Afanasieva

2002-12-01

140

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

 
 
 
 
141

Synthesis of Na-{beta}''-Al{sub 2}O{sub 3} electrolytes by microwave sintering precursors derived from the sol-gel method  

Energy Technology Data Exchange (ETDEWEB)

Na-{beta}''-Al{sub 2}O{sub 3} electrolytes were synthesized by the microwave sintering assisted sol-gel technique in this study. The precursor powders and microwave-sintered pellets were systematically investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (TG-DSC) and Fourier transform infrared (FT-IR) spectroscopy. The ionic conductivity of the microwave-sintered pellets was also measured based on AC impedance spectroscopy. It was found that the calcining temperature of the precursor powders derived from the sol-gel method was the key factor to affect the purity of Na-{beta}''-Al{sub 2}O{sub 3} in the pellets. The sintered pellets prepared from the powders calcined at 850 {sup o}C exhibited a purity of 94.4% Na-{beta}''-Al{sub 2}O{sub 3} and the density of the sintered pellets was 98.91% of the theoretical density of Na-{beta}''-Al{sub 2}O{sub 3}. In addition, the sample showed an ionic conductivity of 0.01085 S cm{sup -1} at 300 {sup o}C by AC impedance measurement.

Wang, Jin; Jiang, Xiao-Ping; Wei, Xiao-Ling [College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu (China); Yang, Hui, E-mail: yanghui@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu (China); Shen, Xiao-Dong [College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu (China)

2010-05-14

142

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

2013-03-01

143

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

2013-12-25

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

Synthesis of 8YSZ-LSGM Composite Thick Film Ceramics for Solid Electrolyte From Nanopowder Utilizing Local Zircon Prepared Using Sol Gel Process  

Science.gov (United States)

Thick film ceramics of 8% mol Y2O3 doped-ZrO2 (8YSZ)-La0.8Sr0.2Ga0.2Mg0.8O3 (LSGM) composite for solid electrolyte have been synthesized from nanopowder. Concentration of LSGM was 0 and 10% weight. A paste for the thick films was made from 8YSZ nanopowder prepared using sol gel method and LSGM powder prepared by solid state reaction. Precursors for the 8YSZ nanopowder preparation were ZrOCl2.8H2O derived from local zircon as byproduct of Tin processing at Bangka Island using caustic fussion method, and Y(NO3)3. The thick films were produced by screen printing technique on alumina substrates. The films were sintered at 1500° C for 2 hours in air. X-ray diffraction (XRD) data showed that the nanopowder of 8YSZ was well produced with broad peaks. The particle size of the 8YSZ powder was about 12 nm as calculated using Debye Scherrer method. The thick films of 8YSZ and 8YSZ-LSGM (90:10 in weight %) composite could be produced, however, the films still contain voids. The ionic conductance of the YSZ-10LSGM films was smaller than that of the YSZ films.

Syarif, Dani Gustaman; Soepriyanto, Syoni; Ismunandar; Korda, Akhmad

2010-10-01

146

Synthesis of 8YSZ-LSGM Composite Thick Film Ceramics for Solid Electrolyte From Nanopowder Utilizing Local Zircon Prepared Using Sol Gel Process  

International Nuclear Information System (INIS)

Thick film ceramics of 8% mol Y2O3 doped-ZrO2(8YSZ)-La0.8Sr0.2Ga0.2Mg0.8O3(LSGM) composite for solid electrolyte have been synthesized from nanopowder. Concentration of LSGM was 0 and 10% weight. A paste for the thick films was made from 8YSZ nanopowder prepared using sol gel method and LSGM powder prepared by solid state reaction. Precursors for the 8YSZ nanopowder preparation were ZrOCl2·8H2O derived from local zircon as byproduct of Tin processing at Bangka Island using caustic fusion method, and Y(NO3)3. The thick films were produced by screen printing technique on alumina substrates. The films were sintered at 1500 deg. C for 2 hours in air. X-ray diffraction (XRD) data showed that the nanopowder of 8YSZ was well produced with broad peaks. The particle size of the 8YSZ powder was about 12 nm as calculated using Debye Scherrer method. The thick films of 8YSZ and 8YSZ-LSGM (90:10 in weight %) composite could be produced, however, the films still contain voids. The ionic conductance of the YSZ-10LSGM films was smaller than that of the YSZ films.

2010-10-24

147

Rheology of high flowing concrete. Koryudo concrete no rheology  

Energy Technology Data Exchange (ETDEWEB)

This review article describes the consistency of high flowing concrete, as for flow resistance, segregation resistance, and sliding resistance. It is provided that the consistency of high flowing concrete should be discussed with relation to the properties of matrix mortar and paste for evaluating it. The yielding value of whole concrete system increases with increasing the adhesion of the matrix mortar, and the viscosity value of whole concrete system increases with increasing the ductility of adhesion flow performance of matrix mortar. It is also provided that the stress state and flowing velocity should be arranged and analyzed by the dimensionless amounts which are not affected by test conditions for various consistency tests of high flowing concrete, to extract the rheological properties of materials. Measurement values thus obtained are suggested to be the evaluation indicators of high flowing concrete. 6 refs., 5 figs., 1 tab.

Tanigawa, Y.; Mori, H. (Nagoya University, Nagoya (Japan). Faculty of Engineering)

1993-08-01

148

Redox transitions in an electrolyte-free myoglobin fluid.  

Science.gov (United States)

Redox responses associated with the heme prosthetic group in a myoglobin-polymer surfactant solvent-free liquid are investigated for the first time in the absence of an electrolyte solution. Cyclic voltammograms from the biofluid exhibit responses that are consistent with planar diffusion of mobile charges in the melt. Temperature-dependent dynamic electrochemical and rheological responses are rationalized in terms of the effective electron hopping rate between heme centers and the transport of intrinsic ionic species in the viscous protein liquid. PMID:24245589

Sharma, Kamendra P; Bradley, Kieren; Brogan, Alex P S; Mann, Stephen; Perriman, Adam W; Fermin, David J

2013-12-11

149

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

150

Electrochemically stable electrolytes  

Energy Technology Data Exchange (ETDEWEB)

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

Angell, Charles Austen (Mesa, AZ); Zhang, Sheng-Shui (Tucson, AZ); Xu, Kang (Tempe, AZ)

1999-01-01

151

Rheologically interesting polysaccharides from yeasts  

Science.gov (United States)

We have examined the relationships between primary, secondary, and tertiary structures of polysaccharides exhibiting the rheological property of friction (drag) reduction in turbulent flows. We found an example of an exopolysaccharide from the yeast Cryptococcus laurentii that possessed high molecular weight but exhibited lower than expected drag reducing activity. Earlier correlations by Hoyt showing that beta 1 --> 3, beta 2 --> 4, and alpha 1 --> 3 linkages in polysaccharides favored drag reduction were expanded to include correlations to secondary structure. The effect of sidechains in a series of gellan gums was shown to be related to sidechain length and position. Disruption of secondary structure in drag reducing polysaccharides reduced drag reducing activity for some but not all exopolysaccharides. The polymer from C. laurentii was shown to be more stable than xanthan gum and other exopolysaccharides under the most vigorous of denaturing conditions. We also showed a direct relationship between extensional viscosity measurements and the drag reducing coefficient for four exopolysaccharides.

Petersen, G. R.; Nelson, G. A.; Cathey, C. A.; Fuller, G. G.

1989-01-01

152

Rheology of tetraphenylborate precipitate slurry  

International Nuclear Information System (INIS)

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

1985-01-01

153

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

154

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

155

Electrolytic refining of gold  

Digital Repository Infrastructure Vision for European Research (DRIVER)

At the request of the editor of ELECTROCHEMICAL INDUSTRY, I herewith give some notes on the electrolytic method of gold refining, to supplement the article of Dr. Tuttle (Vol. I, page 157, January, 1903).

Wohlwill, Emil

2008-01-01

156

On shear rheology of gel propellants  

Energy Technology Data Exchange (ETDEWEB)

Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel-Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine-based fuels, gelled with polysaccharides, were characterized as shear-thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red-fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers-Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Rahimi, Shai; Peretz, Arie [RAFAEL, MANOR Propulsion and Explosive Systems Division, Haifa (Israel); Natan, Benveniste [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

2007-04-15

157

Structural Rheology of the Smectic Phase  

Directory of Open Access Journals (Sweden)

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

Shuji Fujii

2014-07-01

158

Zirconia ceramic solid electrolytes  

International Nuclear Information System (INIS)

Magnesia partially stabilized zirconia ceramic solid electrolytes have been studied for the design of electrochemical transducers for oxygen detection. The main results show that around 3% MgO is the optimum solid solution level for ionic conductivity maximum, 2% alumina addition facilitates densification with no further degradation of the electrical behavior, and that thermal hysteresis of the electrical conductivity in zirconia-magnesia solid electrolytes with alumina additions is due in part to the decrease in cubic phase content. (author)

1990-12-09

159

Quasistatic rheology and the origins of strain  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Features of rheological laws applied to solid-like granular materials are recalled and confronted to microscopic approaches via discrete numerical simulations. We give examples of model systems with very similar equilibrium stress transport properties -- the much-studied force chains and force distribution -- but qualitatively different strain responses to stress increments. Results on the stability of elastoplastic contact networks lead to the definition of two different rheological regimes,...

Roux, Jean-noe?l; Combe, Gae?l

2002-01-01

160

Rheology of compatibilized immiscible viscoelastic polymer blends  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheological behavior of a PS/PE model viscoelastic immiscible blend compatibilized by two types of inter facial modifiers was investigated. Dynamic, steady shear, and transient experiments were performed to probe the effect of the interfacial modification on the rheological behavior of the blend. While the effect was relatively small in dynamic and steady shear experiments, significant signature of the presence of the copolymer was observed in transient experiments after start up of shear flo...

Iza, Mustapha; Bousmina, Mosto; Je?ro?me, Robert

2001-01-01

 
 
 
 
161

Becker and Lomnitz rheological models: a comparison  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Mainardi, Francesco; Spada, Giorgio

2012-01-01

162

Investigation of interfacial rheology & foam stability.  

Energy Technology Data Exchange (ETDEWEB)

The rheology at gas-liquid interfaces strongly influences the stability and dynamics of foams and emulsions. Several experimental techniques are employed to characterize the rheology at liquid-gas interfaces with an emphasis on the non-Newtonian behavior of surfactant-laden interfaces. The focus is to relate the interfacial rheology to the foamability and foam stability of various aqueous systems. An interfacial stress rheometer (ISR) is used to measure the steady and dynamic rheology by applying an external magnetic field to actuate a magnetic needle suspended at the interface. Results are compared with those from a double wall ring attachment to a rotational rheometer (TA Instruments AR-G2). Micro-interfacial rheology (MIR) is also performed using optical tweezers to manipulate suspended microparticle probes at the interface to investigate the steady and dynamic rheology. Additionally, a surface dilatational rheometer (SDR) is used to periodically oscillate the volume of a pendant drop or buoyant bubble. Applying the Young-Laplace equation to the drop shape, a time-dependent surface tension can be calculated and used to determine the effective dilatational viscosity of an interface. Using the ISR, double wall ring, SDR, and MIR, a wide range of sensitivity in surface forces (fN to nN) can be explored as each experimental method has different sensitivities. Measurements will be compared to foam stability.

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

2010-05-01

163

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 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

2003-01-15

164

[Rheology and coronary heart disease].  

Science.gov (United States)

More than 25 years ago it was demonstrated that an improvement in various parameters of blood flow in patients who have an hyperviscosity syndrome improves coronary blood flow. Hyperfibrinogenemia with resulting increase in plasma viscosity and erythrocyte aggregation has been demonstrated in patients with coronary heart disease. Poiseuille's law, which describes the interaction between vascular resistance, vessel geometry and blood viscosity, indicates--when applied to coronary artery disease--that an increase in the viscosity of blood, especially of plasma, can in the poststenotic microcirculation be a flow-limiting factor and a critical determinant of oxygen supply to myocardium that is at risk of ischaemia. An increased concentration of fibrinogen, which is the substance that causes the increase in plasma viscosity, has been shown to correlate prospectively with the risk of serious cardiovascular events. Patients with multiple-vessel coronary heart disease and treatment-refractory angina pectoris have clearly increased fibrinogen values. Chronic intermittent urokinase administrations--given with the aim of achieving fibrinogenolysis of the elevated fibrinogen concentration at a dose of 500 000 IU urokinase three times weekly -improves the rheological parameters and achieves an impressive decrease in symptoms. It is thus important in clinical practice to take into account that patients with atherosclerosis and a fibrinogen concentration of more than 300 mg may develop perfusion disorders and worsening of their symptoms. PMID:19085805

Leschke, M

2008-12-01

165

Rheology of tetraphenylborate precipitate slurry  

International Nuclear Information System (INIS)

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

1985-04-22

166

Lubricant rheology in concentrated contacts  

Science.gov (United States)

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

Jacobson, B. O.

1984-01-01

167

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.

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

168

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

169

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

170

Electrolytically decontaminating device  

International Nuclear Information System (INIS)

Purpose: To enable to electrolytic decontamination of contaminated metal materials in a nuclear power plant effectively and with a reduced amount of liquid wastes. Constitution: This device is put to an operated state by supplying an electrical current between the anode and the cathode, actuating a supersonic vibrator and further blowing airs to form air bubble walls. Since air bubbles uprise from the bottom to the liquid surface and the electrolyte is stirred to carry away metal ions or the likes leached out from the anode externally with no stagnation at the electrode, the surface of the electrode is always exposed to a fresh electrolyte, whereby the polarization is suppressed. The supersonic energy repeats random reflections between the corrugating liquid face and the air bubbles. The supersonic energy passing through the electrodes applied supersonic vibrations to the electrodes thereby destroy the polarization and promote the dissolution of the anode. (Horiuchi, T.)

1983-06-10

171

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

172

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.

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

173

Electrolytic decontamination of stainless steel using a basic electrolyte  

International Nuclear Information System (INIS)

An electrolytic plutonium decontamination process or stainless steel was developed for use as the final step in a proposed radioactive waste handling and decontamination facility to be construced at the Rockwell International Rocky Flats plutonium handling facility. This paper discusses test plan, which was executed to compare the basic electrolyte with phosphoric acid and nitric acid electrolytes. 1 ref

1981-01-01

174

Algorithm for the Automated Generation of Rheological Models.  

Science.gov (United States)

The paper presents a computational approach for generating rheological models. A rheological structure can be analogically described as a set of basic components connected in series or in parallel. The models are automatically created in two different for...

A. C. Capelo L. Ironi S. Tentoni

1990-01-01

175

[Rheologic findings in patients with Eales disease].  

Science.gov (United States)

In a retrospective analysis of findings in 12 patients with Eales' disease significant changes in blood fluidity were established. The six female and six male patients, aged between 15 and 59, were examined in the acute and subclinical stages and when a recurrence occurred. The rheologic parameters plasma viscosity, erythrocyte rigidity, and erythrocyte aggregation were significantly increased in the acute stage and when there was a recurrence, while in the subclinical stage the rheologic values improved to normal. No correlation could be found between the severity of the clinical picture in the various phases and the rheologic values. None of the other biochemical, microbiologic, and immunologic parameters were pathologic in any stage of the disease. In particular, virus serology, protein, immune, and hemoglobin electrophoresis were normal in all patients. While the etiology of Eales' disease remains unknown, deteroration in erythrocyte rigidity appears to play a part in the pathophysiology of the disease. PMID:2586003

Bertram, B; Wolf, S; Hof, A; Jung, F; Reim, M

1989-10-01

176

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

177

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.

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...

2013-01-01

179

Spin coating of electrolytes  

Science.gov (United States)

Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

Stetter, Joseph R. (Naperville, IL); Maclay, G. Jordan (Maywood, IL)

1989-01-01

180

Rheological behavior of coal-water slurry  

Energy Technology Data Exchange (ETDEWEB)

The rheological behavior of some Indian coal-water slurries (CWS) was investigated using a HAAKE RV30 viscometer. The objective was to study the effect of solid concentration, ash content, pH, and temperature on the rheology of CWS. It was found that CWS exhibits pseudoplastic behavior. The apparent viscosity varies with the amount of coal in the slurry, pH, and temperature, which is the highest around pH 6 and the lowest near pH 8. The effect of temperature on the viscosity could be described using an Arrhenius type of relation.

Mishra, S.K.; Senapati, P.K.; Panda, D. [Regional Research Lab., Orissa (India). CPAF Division

2002-02-01

 
 
 
 
181

Effect of rheology on gel placement  

Energy Technology Data Exchange (ETDEWEB)

This paper investigates whether rheology can be exploited to eliminate the need for zone isolation during gel placement. Eight different rheological models were used to represent the properties of existing non-Newtonian gelling agents. Gel placement was examined in linear and radial parallel corefloods and in fractured and unfractured injection wells. The analysis indicates that, compared with water-like gelling agents, existing non-Newtonian gelling agents will not reduce the need for zone isolation during gel placement in radial-flow systems.

Seright, R.S. (New Mexico Petroleum Recovery Research Center (US))

1991-05-01

182

Rheology and stability of magnetite dense media  

Energy Technology Data Exchange (ETDEWEB)

The purpose is to study the relationship between magnetite suspension properties and dense medium separation performance. The experimental studies include development of a method to measure the rheological properties of settling suspensions such as magnetite dense media; characterization of the rheological and settling properties of magnetite dense media; study of the effects of physical, chemical, and mechanical parameters on the medium properties; and examination of the effects of particle density distribution on the medium properties. The research has potential application to the optimization of separation efficiency through control of media properties, such as for processing fine coals and handling disperse systems, such as coal slurries. 266 refs., 130 figs., 31 tabs.

Klein, B. (University of British Columbia, Vancouver, BC (Canada). Department of Mining and Mineral Processing Engineering)

1992-05-01

183

Characterizing the rheology of fluidized granular matter.  

Science.gov (United States)

In this study we characterize the rheology of fluidized granular matter subject to secondary forcing. Our approach consists of first fluidizing granular matter in a drum half filled with grains via simple rotation and then superimposing oscillatory shear perpendicular to the downhill flow direction. The response of the system is mostly linear, with a phase lag between the grain motion and the oscillatory forcing. The rheology of the system can be well characterized by the GDR MiDi model if the system is forced with slow oscillations. The model breaks down when the forcing time scale becomes comparable to the characteristic time for energy dissipation in the flow. PMID:24125256

Desmond, Kenneth W; Villa, Umberto; Newey, Mike; Losert, Wolfgang

2013-09-01

184

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

185

Rheology of latex-modified grouts  

Energy Technology Data Exchange (ETDEWEB)

The pumpability and ability of cementitious grouts to penetrate voids and cracks is strongly dependent on the rheological behavior of the grout. This is important in diverse grouting applications including ground treatment, repair of concrete, reduction of rock or soil permeability, environmental remediation, prestressing concrete, rock anchors, sealing radioactive waste repositories, and well completion. The rheology of grouts containing latex was investigated. The two latex additives used were carboxylated styrene-butadiene and acrylic. The influences of superplasticizer, fly ash, and blast furnace slag on the rheology of latex-modified grouts were addressed. Shear stress-shear rate curves were determined for a variety of mix proportions. The time-dependent behavior of selected grouts was also studied. It was determined that the yield stress and apparent viscosity are influenced by latex content and that the grouts are shear thinning at low water/cement ratios. Latex imparts stability and thixotropy in grouts. Partial replacement of cement with either fly ash or slag diminishes the effect of latex on rheology.

Allan, M.L. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science

1997-12-01

186

Rheological and commodity properties of petroleum mixtures  

International Nuclear Information System (INIS)

Results of researches of rheological and commodity characteristics of prognosis petroleum mixtures, pumping on an Western Kazakhstan-Kumkol petroleum pipe-line are presented. It is shown, that petroleum mixtures are low viscous, low solidifying and have not viscosity anomaly at positive temperatures. (author)

1997-11-04

187

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

188

Aggregate of nanoparticles: rheological and mechanical properties  

Directory of Open Access Journals (Sweden)

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

Wang Yu

2011-01-01

189

Aggregate of nanoparticles: rheological and mechanical properties  

Science.gov (United States)

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

Wang, Yu; Wu, Xiaojun; Yang, Wei; Zhai, Yuanming; Xie, Banghu; Yang, Mingbo

2011-12-01

190

Advances in rheology. Volume 4: Applications  

Energy Technology Data Exchange (ETDEWEB)

This book contains over 50 selections. Some of the titles are: Rheology and mass transfer in a stationary or pulsatile two phase flow of suspended particles investigated by electrochemical techniques; The helical screw rheometer; Characterization of polymer solutions in flow through porous media; A discrete model for the recovery of oil from a reservoir; and Nonlinear creep characteristics of Devonian oil shale.

Mena, B.; Garcia-Rejon, A.; Rangel-Nafaile, C.

1984-01-01

191

RHEOLOGY OF CONCENTRATED SOLUTIONS OF HYPERBRANCHED POLYESTERS  

Science.gov (United States)

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

192

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

1998-01-01

193

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

194

Organic polymer gel electrolyte for Li-ion batteries  

Energy Technology Data Exchange (ETDEWEB)

The present paper describes a novel synthesis of organic polymer gel electrolyte for Li-ion cell, comprising of Polyethylene oxide (PEO), LiClO{sub 4}, LiOH, Li{sub 2}SO{sub 4} and dimethyl formamide (DMF). The gel was obtained with a specific weight ratio of these components after appropriate heat treatment. The gel when layered over graphite plate and LiCoO{sub 2} cathode, it forms laboratory model Li-ion cell. The cell shows an OCP value of 3.624V at 298K. The galvanostatic charge/discharge tests show performances comparable to liquid electrolyte system. (author)

Basumallick, I.; Roy, Pankaj; Chatterjee, Abhik; Bhattacharya, Arup; Chatterjee, Someswar; Ghosh, Susanta [Electrochemical Laboratory, Department of Chemistry, Visva-Bharati University, Santiniketan 731235, West Bengal (India)

2006-11-22

195

Electrolytic 99TcO4- reduction at inert electrodes  

International Nuclear Information System (INIS)

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

1990-05-17

196

The rheological properties of different GNPs  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Rheological analysis can be employed as a sensitive tool in predicting the physical properties of gold nanoparticles (GNPs. Understanding the rheological properties of GNPs can help to develop a better therapeutic cancer product, since these physical properties often link material formulation and processing stages with the ultimate end use. The rheological properties of GNPs have not been previously documented. The present study attempted to characterize the rheological properties of different sizes of GNPs at: 1 fixed temperature and wide range of shear rates; 2 varied temperature and fixed shear rate. Methods 10, 20 and 50 nm GNPs was used in this study. Several rheological parameters of GNPs such as viscosity, torque%, shear stress and shear rate were evaluated using Brookfield LVDV-III Programmable rheometer supplied with temperature bath and controlled by a computer. To measure fluid properties (viscosity as function of shear rate, e.g., to determine whether the flow is Newtonian or non-Newtonian flow behaviour, and viscoelasticity (viscosity as function of temperature, rheological parameters were firstly measured at starting temperature of 37°C and wide range of shear rates from 375 to 1875 s-1, and secondly at a gradual increase of temperature from 37 to 42°C and fixed shear rate of 1875 s-1. Results The 10, 20 and 50 nm GNPs showed mean size of 9.45 ± 1.33 nm, 20.18 ± 1.80 nm, and 50 nm GNPs, respectively. The 10 and 20 nm GNPs showed spherical morphology while 50 nm GNPs showed hexagonal morphology using the transmission electron microscope (TEM. The relation between viscosity (cp and shear rate (s-1 for 10, 20 and 50 nm GNPs at a temperature of 37°C showed non-Newtonian behaviour. Although the relationship between SS (dyne/cm2 and SR (s-1 for 10, 20 and 50 nm GNPs was linearly related however their fluid properties showed non-Newtonian behaviour. Conclusions The torque%, viscosity (cp and SS (dyne/cm2 of all GNP sizes decreased with increasing the temperature and with decreasing the GNP size (for each fixed temperature value. For each shear rate value, the viscosity of all GNPs decreased with decreasing the GNP size. This study demonstrates that the physical, dimensional and morphological changes of GNPs have effective influence on their rheological properties. To understand and categorize the role of GNPs in drug delivery and cancer therapy, GNPs of varying size, number of particles, shape and surface should be taken into consideration. Moreover, further additional in vivo studies after administration of GNPs in rats should be performed to support this hypothesis.

Abdelhalim Mohamed Anwar K

2012-01-01

197

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

1981-01-01

198

Sodium conducting polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

This section deals with the aspects of ionic conduction in general as well as specific experimental results obtained for sodium systems. The conductivity as a function of temperature and oxygen/metal ratio are given for the systems NaI, NaCF/sub 3/SO/sub 3/ and NaClO/sub 4/ plus polyethylene oxide. Attempts have been made to produce mixed phase solid electrolytes analogous to the lithium systems that have worked well. These consist of mixtures of polymer and a solid electrolyte. The addition of both nasicon and sodium beta alumina unexpectedly decreases the ionic conductivity in contrast to the lithium systems. Addition of the nonconducting silica AEROSIL in order to increase the internal surface area has the effect of retarding the phase transition at 60 deg. C, but does not enhance the conductivity. (author) 23 refs.

Skaarup, S.; West, K. (eds.)

1989-04-01

199

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

200

Solid polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to Li ion (Li{sup +}) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF{sub 3}SO{sub 2}){sub 2}, LiAsF{sub 6}, and LiClO{sub 4}. 2 figs.

Abraham, K.M.; Alamgir, M.; Choe, H.S.

1995-12-12

 
 
 
 
201

Solid polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF.sub.3 SO.sub.2).sub.2, LiAsF.sub.6, and LiClO.sub.4.

Abraham, Kuzhikalail M. (Needham, MA); Alamgir, Mohamed (Dedham, MA); Choe, Hyoun S. (Waltham, MA)

1995-01-01

202

Electrolyte Concentrates Treat Dehydration  

Science.gov (United States)

Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

2009-01-01

203

Thin film composite electrolyte  

Energy Technology Data Exchange (ETDEWEB)

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

204

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

205

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

206

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

207

Polymer-ceramic composite electrolytes  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews the state-of-the-art of polymer-ceramic composite electrolytes in view of three main issues, i.e., conductivity, transport number, and electrode-electrolyte interfacial reactions. These issues are believed to be critical to the development and commercialization of solid polymer batteries. The ceramic phase in limited amounts augments conductivity, enhances the cationic transport number, and suppresses electrode-electrolyte interfacial reactions. Scientific explanation for these effects is also discussed. (orig.)

Kumar, B. (University of Dayton Research Inst., Dayton, OH (United States) Aero Propulsion and Power Directorate, Wright Laboratory, Wright-Patterson Air Force Base, OH (United States)); Scanlon, L.G. (University of Dayton Research Inst., Dayton, OH (United States) Aero Propulsion and Power Directorate, Wright Laboratory, Wright-Patterson Air Force Base, OH (United States))

1994-12-01

208

Lithium sulfide compositions for battery electrolyte and battery electrode coatings  

Science.gov (United States)

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

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

2013-12-03

209

Rheological properties of a calcium smectite  

International Nuclear Information System (INIS)

The rheological and mechanical properties of a Ca-smectite have been investigated by different laboratory tests. By these tests the permeability, the water uptake properties, the swelling properties, the swelling pressure, the stress-strain properties, the strength and the creep properties have been determined. The influence of density, temperature, time and stress level have been considered. Mathematical models of the measured properties and behavior of the clay have been suggested so that calculations involving mechanical and rheological scenarios can be made. The behavior of the clay have been discussed with reference to the microstructure and comparisons between the investigated Ca-smectite and a Na-smectite (Mx-80) have been made. One main conclusion is that the difference between the properties and behavior of Ca-smectite and Na-smectite is small at densities >2.0 t/m3. At densities 3 the difference is increasing with decreasing density. (orig./HP)

1987-01-01

210

Shear thickening, frictionless and frictional rheologies  

CERN Document Server

Particles suspended in a Newtonian fluid raise the viscosity and also generally give rise to a shear-rate dependent rheology. In particular, pronounced shear thickening is observed at large solid volume fractions. In a recent article (R. Seto, R. Mari, J. F. Morris, and M. M. Denn., Phys. Rev. Lett., 111:218301, 2013) we have considered the minimum set of components to reproduce the experimentally observed shear thickening behavior, including Discontinuous Shear Thickening (DST). We have found frictional contact forces to be essential, and were able to reproduce the experimental behavior by a simulation including this physical ingredient. In the present article, we thoroughly investigate the effect of friction and express it in the framework of the jamming transition. The viscosity divergence at the jamming transition has been a well known phenomenon in suspension rheology, as reflected in many empirical laws for the viscosity. Friction can affect this divergence, and in particular the jamming packing fractio...

Mari, Romain; Morris, Jeffrey F; Denn, Morton M

2014-01-01

211

Comments on ER (electrorheological) fluid rheology  

Energy Technology Data Exchange (ETDEWEB)

The label electrorheological (ER) fluid reflects the salient feature of these materials that continues to attract the attention of scientists and technologists alike. This is the ability to induce significant changes in rheology through an applied electric field. This electrically induced transformation of a fluid-like suspension of nonconducting particles and liquid, to a solid-like gel with a yield stress and corresponding high viscosity, is as useful as it is striking. The ability to characterize and understand this so-called Winslow effect is fundamental to successful applications. The current interest in ER fluid development provides strong motivation to rheologists. Our purpose here is to discuss briefly some principles of rheology that apply to ER fluids; they range from well-established and familiar to somewhat subtle. We will focus on the measurement of viscosity and yield stress. 8 refs., 2 figs.

Kraynik, A.M.

1989-01-01

212

Glass electrolyte composition  

Energy Technology Data Exchange (ETDEWEB)

An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na.sub.2 O, ZrO.sub.2, Al.sub.2 O.sub.3 and SiO.sub.2 in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2.times.10.sup.-3 (ohm-cm).sup.-1 at 300.degree. C. and a glass transition temperature in excess of 500.degree. C.

Kucera, Gene H. (Downers Grove, IL); Roche, Michael F. (Downers Grove, IL)

1985-01-01

213

RELATIONSHIP BETWEEN MORPHOLOGY, RHEOLOGY AND GLUCOAMYLASE PRODUCTION BY Aspergillus awamori IN SUBMERGED CULTURES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of inoculum preparation on Aspergillus awamori morphology, broth rheology and glucoamylase synthesis in submerged cultures was investigated. A series of runs were performed in fermenters, using initial total reducing sugar concentrations of 20 g/L and 80 g/L. The inocula were prepared in a rotary shaker, at 35oC and 200 rev/min, using a spore concentration of 9.2 x 105 spores/mL and varying both cultivation time and medium pH during the spore germination step. Three types of ino...

Pamboukian, C. R. D.; Facciotti, M. C. R.; Schmidell, W.

1998-01-01

214

Multiphysical modeling of third-body rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As the rheology of the third body does not only depend on its mechanical properties, classical discrete element simulations are not capable of modeling its flows. Consequently to take into account the third body's mechanical, thermal and physicochemical properties, an extended discrete element approach is proposed and applied to the simulation of third-body flows. Each extension of the standard DEM model is compared to experimental results. The extended model's efficiency is demonstrated by u...

Renouf, Mathieu; Cao, Hong-phong; Nhu, Viet-hung

2011-01-01

215

Review. Rheological properties of biological materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Eucaryotic cells and biological materials are described from a rheological point of view. Single cell properties give rise to typical microrheological properties which can aect cell behaviour, in close connection with their adhesion properties. Single cell properties are also important in the context of multicellular systems, i.e. in biological tissues. Results from experiments are analyzed and models proposed both at the cellular scale and the macroscopic scale.

Verdier, Claude; Etienne, Jocelyn; Duperray, Alain; Preziosi, Luigi

2009-01-01

216

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

1986-01-01

217

Characterization, rheology and microstructure of laponite suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The research presented in this thesis is part of a broader ongoing effort aimed at validating at the laboratory scale the use of laponite suspensions for treating liquefiable soils, as an alternative to sodium pyro-phosphate treated bentonite suspensions. The specific objectives of the work were: (a) the characterization of laponite—a material new to the geotechnical community, (b) a study of the rheology of concentrated laponite-water suspensions, and (c) an investigation into differences ...

2011-01-01

218

Rheological characterization of Poloxamer 407 nimesulide gels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thermal gelling property of Poloxamer 407- nimesulide gels was characterized by rheological studies. Nimesulide, a local anti-inflammatory and anesthetic drug used for the treatment of acute and chronic pain, has a short duration of action and a long-acting single-dose injection would be of clinical importance. Thus a poloxamer 407 gel applied intramuscularly could prolong the release and action of nimesulide. In this study, aqueous gels with nimesulide, containing three different concent...

Freitas, M. N.; Farah, M.; Bretas, R. E. S.; Ricci-ju?nior, E.; Marchetti, J. M.

2009-01-01

219

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

220

Rheological properties of olefinic thermoplastic elastomer blends:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermoplastic Elastomers (TPE) are a class of materials that have rubber-like properties and can be processed like thermoplastic polymers. In this thesis, the rheological properties of two TPE blends are correlated to their morphology. The thermoplastic vulcanisates (TPV) consist of micron-sized, cured elastomer particles while the blends of PP and the triblock copolymer SEBS show co-continuous structures. Both blends also contain considerable amount of paraffinic oil.

Sengers, W. G. F.

2005-01-01

 
 
 
 
221

Two dimensional foam rheology with viscous drag  

CERN Multimedia

We formulate and apply a continuum model that incorporates elasticity, limit stress, plasticity and viscous drag. It is motivated by the two-dimensional foam rheology experiment of Debregeas \\emph{et al.} [G. Debr\\'egeas, H. Tabuteau, and J.-M. di Meglio, {\\em Phys. Rev. Lett.} {\\bf 87}, 178305 (2001).], and is successful in exhibiting its principal feature, that is velocity and strain localisation. Transient effects are also identified.

Weaire, D; Hutzler, S

2006-01-01

222

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

223

A rheological investigation of vesicular rhyolite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rheology of vesiculating rhyolitic systems exerts a strong control on the transport of silicic magmas in the subvolcanic to volcanic environments. We present here an investigation of vesiculating and vesiculated rhyolites using dilatometric methods. This study examines the effect of vesicle content on the viscosity of a natural supercooled rhyolitic liquid with 0–70% vesicles. The experimental samples of rhyolitic glass are derived from fusion of a natural obsidian from Little Glass...

Bagdassarov, Nikolai; Dingwell, Donald B.

1992-01-01

224

First International Symposium on Polymer Electrolytes  

Science.gov (United States)

Contents: Insights into ion-matrix and ion-ion couplings in polymer-salt electrolytes from relaxation spectroscopy; Proton conductors; diffusion of ions on polymer electrolytes; Comb shaped polymer electrolytes; Cross-linked polyethers as media for ionic ...

1987-01-01

225

Electrolytes - Technology review  

Science.gov (United States)

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.

Meutzner, Falk; de Vivanco, Mateo Ureña

2014-06-01

226

Rheological Behavior Analysis of Liver Fibrosis in Rats  

Directory of Open Access Journals (Sweden)

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

Ying Zhu

2013-05-01

227

Rheological properties of cementitious composites in fresh state  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Doctoral dissertation discusses the concept of the rheology of fresh cement based composites. On the territory of Slovenia, no one has dealt with the topic of rheology of fresh cement based composites with an emphasis on concrete. For this reason, the task is based more generally. Dissertation discusses the basic principles of the rheology of fresh cement composites and is then directed in a more specific topic. Reographs for use with Slovenian materials are established. Basic principles of r...

Hoc?evar, Andraz?

2013-01-01

228

Filling Batteries Precisely With Electrolyte  

Science.gov (United States)

Apparatus includes conductivity probe detecting arrival of liquid filling at specified level. Enables precise, rapid, and reproducible filling of electrochemical cells with electrolyte solutions to specified levels, providing specified void volumes in cells. Cell-filling apparatus includes electrolyte-level-measuring conductivity probe plus means to deliver solution in small periodic volumes after bulk of solution delivered to cell.

Lutwack, Ralph

1992-01-01

229

Thin film polymeric gel electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

1996-01-01

230

Physics of Electrolytic Gas Evolution  

CERN Document Server

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

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

2013-01-01

231

Thin film polymeric gel electrolytes  

Science.gov (United States)

Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

1996-12-31

232

Lithium Battery with Inorganic Electrolyte.  

Science.gov (United States)

Experimental lithium anode cells with inorganic electrolytes operable at ambient temperatures as well as at temperatures as low as -40C were made using the POCl3-SOCl2 solvent system. Using a 1.2M LiBCl4 solution in the solvent as electrolyte, a conductiv...

A. Heller J. J. Auborn K. French S. Liberman V. Shah

1972-01-01

233

Perovskite solid electrolytes for SOFC  

International Nuclear Information System (INIS)

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

1992-07-01

234

Electrolyte treatment for aluminum reduction  

Energy Technology Data Exchange (ETDEWEB)

A method of treating an electrolyte for use in the electrolytic reduction of alumina to aluminum employing an anode and a cathode, the alumina dissolved in the electrolyte, the treating improving wetting of the cathode with molten aluminum during electrolysis. The method comprises the steps of providing a molten electrolyte comprised of ALF.sub.3 and at least one salt selected from the group consisting of NaF, KF and LiF, and treating the electrolyte by providing therein 0.004 to 0.2 wt. % of a transition metal or transition metal compound for improved wettability of the cathode with molten aluminum during subsequent electrolysis to reduce alumina to aluminum.

Brown, Craig W. (Seattle, WA); Brooks, Richard J. (Seattle, WA); Frizzle, Patrick B. (Seattle, WA); Juric, Drago D. (Bulleen, AU)

2002-01-01

235

Electrolytes and thermoregulation  

Science.gov (United States)

The influence of ions on temperature is studied for cases where the changes in ionic concentrations are induced by direct infusion or injection of electrolyte solutions into the cerebral ventricles or into specific areas of brain tissue; intravenous infusion or injection; eating food or drinking solutions of different ionic composition; and heat or exercise dehydration. It is shown that introduction of Na(+) and Ca(++) into the cerebral ventricles or into the venous system affects temperature regulation. It appears that the specific action of these ions is different from their osmotic effects. It is unlikely that their action is localized to the thermoregulatory centers in the brain. The infusion experiments demonstrate that the changes in sodium balance occurring during exercise and heat stress are large enough to affect sweat gland function and vasomotor activity.

Nielsen, B.; Greenleaf, J. E.

1977-01-01

236

Ice electrode electrolytic cell  

Energy Technology Data Exchange (ETDEWEB)

The use of an ice electrode for the electrolytic removal of heavy metals from waste solutions was evaluated in laboratory studies. Deposition voltages are slightly different from typical solid electrodes. However, unlike solid electrodes, metal deposits on an ice electrode as small particles that are trapped in the growing ice layer. The particulate nature of the electrodeposit provides a steady increase in the active surface area of the electrode. It was determined that all plateable metals are candidates for removal from solution at an ice electrode. In addition, nonplatable metals, such as uranium and tungsten, can be precipitated as salts at an ice electrode. A bench scale continuous flow system has been designed and fabricated based on the laboratory studies. This system has been demonstrated for removal of copper during four extended runs.

Glenn, D.F.; Ingram, J.C.; Prescott, D.S. [and others

1994-12-31

237

POLYMER ELECTROLYTE MEMBRANE FUEL CELLS  

DEFF Research Database (Denmark)

A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes. With the thermally resistant polymer, e.g., polybenzimidazole or a mixture of polybenzimidazole and other thermoplastics as binder, the carbon-supported noble metal catalyst is tape-cast onto a hydrophobic supporting substrate. When doped with an acid mixture, electrodes are assembled with an acid doped solid electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte fuel cells.

Bjerrum, Niels Technical University of Denmark,

238

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

239

Organic electrolytes for sodium batteries  

Science.gov (United States)

A summary of earlier given status reports in connection with the project on organic electrolytes for sodium batteries is presented. The aim of the investigations was to develop new room temperature molten salts electrolytes mainly with radical substituted heterocyclic organic chlorides mixed with aluminum chloride. The new electrolytes should have an ionic conductivity comparable with MEIC1:AlCl3 or better. A computer model program MOPAC (Molecular Orbital Package) was to be included to calculate theoretically reduction potentials for a variety of organic cations. Furthermore, MOPAC could be utilized to predict the electron densities, and then give a prediction of the stability of the organic cation.

Vestergaard, B.

1992-09-01

240

pH effects on the molecular structure of ?-lactoglobulin modified air-water interfaces and its impact on foam rheology.  

Science.gov (United States)

Macroscopic properties of aqueous ?-lactoglobulin (BLG) foams and the molecular properties of BLG modified air-water interfaces as their major structural element were investigated with a unique combination of foam rheology measurements and interfacial sensitive methods such as sum-frequency generation and interfacial dilatational rheology. The molecular structure and protein-protein interactions at the air-water interface can be changed substantially with the solution pH and result in major changes in interfacial dilational and foam rheology. At a pH near the interfacial isoelectric point BLG molecules carry zero net charge and disordered multilayers with the highest interfacial dilatational elasticity are formed at the air-water interface. Increasing or decreasing the pH with respect to the isoelectric point leads to the formation of a BLG monolayer with repulsive electrostatic interactions among the adsorbed molecules which decrease the interfacial dilational elasticity. The latter molecular information does explain the behavior of BLG foams in our rheological studies, where in fact the highest apparent yield stresses and storage moduli are established with foams from electrolyte solutions with a pH close to the isoelectric point of BLG. At this pH the gas bubbles of the foam are stabilized by BLG multilayers with attractive intermolecular interactions at the ubiquitous air-water interfaces, while BLG layers with repulsive interactions decrease the apparent yield stress and storage moduli as stabilization of gas bubbles with a monolayer of BLG is less effective. PMID:23961700

Engelhardt, Kathrin; Lexis, Meike; Gochev, Georgi; Konnerth, Christoph; Miller, Reinhard; Willenbacher, Norbert; Peukert, Wolfgang; Braunschweig, Björn

2013-09-17

 
 
 
 
241

Nonlinear rheological response of colloidal glass  

Science.gov (United States)

I review a first principles approach to the non-linear rheology of dense colloidal dispersions. Assuming homogeneous flow and neglecting hydrodynamic interactions, a theoretical description of the stresses, micro-structure, and particle motion close to a colloidal glass transition are developed. Results for large amplitude oscillatory shearing, step-strains, and other time-dependent transient deformation protocols provide a unifying description of the dispersion properties under general strains including non-stationary situations. Shear-thinning, plastic deformation and an-elastic behaviour are observed. Adding Brownian dynamics simulations, the shear-induced particle motion provides information on the microscopic transport mechanisms in the dense dispersions.

Fuchs, M.

2013-02-01

242

Rheology of coal-oil dispersions  

Energy Technology Data Exchange (ETDEWEB)

BP has developed a novel method of preparing very stable dispersions containing up to 50% wt. coal in fuel oil. These dispersions offer the potential for utilising coal in existing equipment designed to store, handle and fire heavy fuel oil. The rheology of these materials is of great importance. In this paper, data are presented to demonstrate that coal-oil dispersions can be handled in a manner similar to fuel oil. Modelling of the variations of viscosity with shear rate, temperature and coal concentration is described. The results of larger scale field pumping trials with an experimental 40% wt. coal-heavy fuel oil dispersion are also described.

Anderson, P.C.

1982-05-01

243

Critical review of the foam rheology literature  

Energy Technology Data Exchange (ETDEWEB)

The rheology of foam is not like that of simpler fluids which can be regarded as mathematical continua. The difference arises because the size of foam bubbles is not infinitesimal relative to the width of the flow channels and because foam (whether gas-in-liquid or liquid-in-liquid) contains a high volume fraction (in excess of 74% for a monodisperse system) of the discontinuous phase. Special emphasis is given to recent work that evaluates the critical yield stress in idealized cases and makes is possible to relate measured apparent viscosities of foams in large channels to a usually unmeasured boundary effect.

Heller, J.P.; Kuntamukkula, M.S.

1987-02-01

244

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 (Capricorn, and Australia plates in the Indian Ocean.

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

2011-12-01

245

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

246

Gelled Polymerizable Microemulsions. Part 3 Rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This is the first report on the rheological properties of oil-gelled polymerizable bicontinuous microemulsions. The polymerizable base system consists of H2O / NIPAm / BisAm – n-dodecane – C13/15E5 (a technical grade n-alkyl polyglycol ether), where NIPAm denotes the monomer N-isopropylacrylamide and BisAm the cross-linker N,N?-methylene bisacrylamide. For the planned polymerization of the aqueous phase a scaffold is needed to preserve the structure of the templating microemulsion durin...

Magno, Miguel; Tessendorf, Renate; Medronho, Bruno; Miguel, Maria G.; Stubenrauch, Cosima

2009-01-01

247

Melt rheology and its applications in the plastics industry  

CERN Multimedia

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

248

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

Directory of Open Access Journals (Sweden)

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

Luk’yanov Nikolai Andreevich

2013-05-01

249

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 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

2005-01-01

250

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

251

Ceramic-metal solid electrolytes  

Energy Technology Data Exchange (ETDEWEB)

The sodium-sulfur battery is a candidate for application to electric vehicles and utility load-leveling. The electrolyte in this battery, ..beta..-Al/sub 2/O/sub 3/, often fails by fracture, which in many cases is initiated by electrolytic degradation. Technology developed at ORNL to produce shock-resistant mechanically tough ..cap alpha..-Al/sub 2/O/sub 3/-based cermets has been extended to include solid electrolytes based on ..beta..-Al/sub 2/O/sub 3/. Compositions examined, ..beta..-Al/sub 2/O/sub 3/-Pt and ..beta..-Al/sub 2/O/sub 3/-Cr, were found to have ionic conductivities comparable to ..beta..-Al/sub 2/O/sub 3/ fabricated in the same way. No special problems with the submicron-size metal inclusions were observed in preliminary tests. This concept is generic and could conceivably be applied to ceramic solid electrolytes in other chemical systems.

Lauf, R.J.; Morgan, C.S.

1982-03-01

252

Solid polymer electrolyte lithium batteries  

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-01-01

253

Feeding electrolyte for sport horses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Bergero, Domenico; Valle, Emanuela

2008-01-01

254

High cation transport polymer electrolyte  

Energy Technology Data Exchange (ETDEWEB)

A solid state ion conducting electrolyte and a battery incorporating same. The electrolyte includes a polymer matrix with an alkali metal salt dissolved therein, the salt having an anion with a long or branched chain having not less than 5 carbon or silicon atoms therein. The polymer is preferably a polyether and the salt anion is preferably an alkyl or silyl moiety of from 5 to about 150 carbon/silicon atoms.

Gerald, II, Rex E. (Brookfield, IL); Rathke, Jerome W. (Homer Glen, IL); Klingler, Robert J. (Westmont, IL)

2007-06-05

255

Solid electrolytes: Problems and solutions  

International Nuclear Information System (INIS)

Degradation phenomena occurring in sodium ?''-alumina solid electrolytes as a consequence of their use in sodium/sulfur batteries are reviewed. Four classes of degradation are discussed: electrolyte reduction, crack propagation, internal sodium precipitation, and reaction with the polysulfide electrode. While degradation reactions may adversely affect cell life, it has been found that these deleterious effects may be avoided by impurity control of the system and by microstructural modification of the ceramic, including grain size control and zirconia-dispersion toughening

1986-01-01

256

Hectorite-based nanocomposite electrolytes for lithium-ion batteries  

Science.gov (United States)

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

Riley, Michael William

257

Improving feed slurry rheology by colloidal techniques  

Energy Technology Data Exchange (ETDEWEB)

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 SiO/sub 2/ 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 % SiO/sub 2/ colloidal suspension (approx. 10-micron particle size) for the -325 mesh (less than or equal to 44-micron particle size) raw-chemical SiO/sub 2/; 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.

Heath, W.O.; Ternes, R.L.

1984-06-01

258

Rheological Behavior of Schizophyllan in Fermentation System  

Directory of Open Access Journals (Sweden)

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

Rekha S. Singhal

2011-01-01

259

Rheological changes in irradiated chicken eggs  

International Nuclear Information System (INIS)

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

1998-06-01

260

Rheology of asphaltene-toluene/water interfaces.  

Science.gov (United States)

The stability of water-in-crude oil emulsions is frequently attributed to a rigid asphaltene film at the water/oil interface. The rheological properties of these films and their relationship to emulsion stability are ill defined. In this study, the interfacial tension, elastic modulus, and viscous modulus were measured using a drop shape analyzer for model oils consisting of asphaltenes dissolved in toluene for concentrations varying from 0.002 to 20 kg/m(3). The effects of oscillation frequency, asphaltene concentration, and interface aging time were examined. The films exhibited viscoelastic behavior. The total modulus increased as the interface aged at all asphaltene concentrations. An attempt was made to model the rheology for the full range of asphaltene concentration. The instantaneous elasticity was modeled with a surface equation of state (SEOS), and the elastic and viscous moduli, with the Lucassen-van den Tempel (LVDT) model. It was found that only the early-time data could be modeled using the SEOS-LVDT approach; that is, the instantaneous, elastic, and viscous moduli of interfaces aged for at most 10 minutes. At longer interface aging times, the SEOS-LVDT approach was invalid, likely because of irreversible adsorption of asphaltenes on the interface and the formation of a network structure. PMID:16316096

Sztukowski, Danuta M; Yarranton, Harvey W

2005-12-01

 
 
 
 
261

Rheology of rock glaciers: a preliminary assessment  

Energy Technology Data Exchange (ETDEWEB)

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

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

1985-01-01

262

Microstructure and rheology of lime putty.  

Science.gov (United States)

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

Ruiz-Agudo, E; Rodriguez-Navarro, C

2010-03-16

263

Rheology and microstructure of concentrated suspensions  

International Nuclear Information System (INIS)

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

1990-04-16

264

Chinese Lithosphere Rheology and Geodynamic Modeling  

Science.gov (United States)

Rock rheology is of critical importance to affect lithosphere deformation. Laboratory experiments show that viscosity of rocks strongly depends on temperature. Therefore, reliable estimation of geotherm is the first step for understanding lithospheric rheology. Deduction of geotherm from surface heat flow and thermal conductivity has been applied widely. However, error in temperature estimated this way increases with depth. In our study, we use seismic tomographic data to estimate mantle temperature ranges 50 to 200 km depth, and get a better constraint of temperature at depth. We use new petrology data to construct the crustal structure and viscosity model of China. To test the validity of extrapolation of flow law of rock from laboratory sample size and higher strain rate to large field scale and much lower strain rate, we use post seismic GPS deformation observation to invert lower crust viscosity for comparison. We then apply the viscosity model to simulate a number of tectonic problems in China, such as GPS velocity clockwise rotation around the eastern syntax of the Himalaya and uplift of the Tibetan plateau, decoupling of stress indicated by compression in the upper crust and extensional normal fault earthquake in the upper mantle in Taiwan southwest coast, and different stress accumulation rate in the upper and lower crust in Longmenshan area, Sichuan Province to estimate the reccurence time of large earthquakes.

Shi, Y.; Zhang, H.; Cao, J.; Zhang, C.; Sun, L.

2009-04-01

265

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

266

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

267

Ionic liquids as electrolytes  

International Nuclear Information System (INIS)

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

2006-08-15

268

Polymer electrolyte fuel cells  

Science.gov (United States)

The recent increase in attention to polymer electrolyte fuel cells (PEFC's) is the result of significant technical advances in this technology and the initiation of some projects for the demonstration of complete PEFC-based power system in a bus or in a passenger car. A PEFC powered vehicle has the potential for zero emission, high energy conversion efficiency and extended range compared to present day battery powered EV's. This paper describes recent achievements in R&D on PEFC's. The major thrust areas have been: (1) demonstration of membrane/electrode assemblies with stable high performance in life tests lasting 4000 hours, employing ultra-low Pt loadings corresponding to only 1/2 oz of Pt for the complete power source of a passenger car; (2) effective remedies for the high sensitivity of the Pt electrocatalyst to impurities in the fuel feed stream; and (3) comprehensive evaluation of the physicochemical properties of membrane and electrodes in the PEFC, clarifying the water management issues and enabling effective codes and diagnostics for this fuel cell.

Gottesfeld, S.

269

Effect of hydroxyapatite morphology/surface area on the rheology and processability of hydroxyapatite filled polyethylene composites.  

Science.gov (United States)

The commercial success of hydroxyapatite (HA) filled polyethylene composite has generated growing interest in improving the processability of the composite. A number of synthetic procedures and post synthesis heat treatment of HA has lead to the availability of powders with widely varying morphological features. This paper addresses the effect of morphological features of HA on the rheology and processability of an injection-moulding grade HA-HDPE composite. The results showed that low surface area HA filled composite exhibited better injection processing characteristics through improved rheological responses. The effect of reducing the surface area of the filler is to require less polyethylene to wet the filler and allows more polyethylene to be involved in the flow processes. These changes reduced the temperatures and pressures required for successful processing. PMID:12194532

Joseph, R; McGregor, W J; Martyn, M T; Tanner, K E; Coates, P D

2002-11-01

270

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

271

Lithium Polymer Electrolytes and Solid State NMR  

Science.gov (United States)

Research is being done at the Glenn Research Center (GRC) developing new kinds of batteries that do not depend on a solution. Currently, batteries use liquid electrolytes containing lithium. Problems with the liquid electrolyte are (1) solvents used can leak out of the battery, so larger, more restrictive, packages have to be made, inhibiting the diversity of application and decreasing the power density; (2) the liquid is incompatible with the lithium metal anode, so alternative, less efficient, anodes are required. The Materials Department at GRC has been working to synthesize polymer electrolytes that can replace the liquid electrolytes. The advantages are that polymer electrolytes do not have the potential to leak so they can be used for a variety of tasks, small or large, including in the space rover or in space suits. The polymers generated by Dr. Mary Ann Meador's group are in the form of rod -coil structures. The rod aspect gives the polymer structural integrity, while the coil makes it flexible. Lithium ions are used in these polymers because of their high mobility. The coils have repeating units of oxygen which stabilize the positive lithium by donating electron density. This aids in the movement of the lithium within the polymer, which contributes to higher conductivity. In addition to conductivity testing, these polymers are characterized using DSC, TGA, FTIR, and solid state NMR. Solid state NMR is used in classifying materials that are not soluble in solvents, such as polymers. The NMR spins the sample at a magic angle (54.7') allowing the significant peaks to emerge. Although solid state NMR is a helpful technique in determining bonding, the process of preparing the sample and tuning it properly are intricate jobs that require patience; especially since each run takes about six hours. The NMR allows for the advancement of polymer synthesis by showing if the expected results were achieved. Using the NMR, in addition to looking at polymers, allows for participation on a variety of other projects, including aero-gels and carbon graphite mat en als. The goals of the polymer electrolyte research are to improve the physical properties of the polymers. This includes improving conductivity, durability, and expanding the temperature range over which it is effective. Currently, good conductivity is only present at high temperatures. My goals are to experiment with different arrangements of rods and coils to achieve these desirable properties. Some of my experiments include changing the number of repeat units in the polymer, the size of the diamines, and the types of coil. Analysis of these new polymers indicates improvement in some properties, such as lower glass transition temperature; however, they are not as flexible as desired. With further research we hope to produce polymers that encompass all of these properties to a high degree.

Berkeley, Emily R.

2004-01-01

272

Experimental Investigation of Orthoenstatite Single Crystal Rheology  

Science.gov (United States)

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

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

2013-12-01

273

Rheology of Two-Phase Systems  

Science.gov (United States)

Ductile shear zones commonly contain distinctive bands of high strain rock characterized by dispersed fine-grained two-phase or polyphase material. Microstructure and weak CPO suggest that these may deform primarily by grain-boundary diffusion creep. It is unclear how such zones develop, how the phases become evenly dispersed, what controls their rheology, and what controls their grain-size evolution. We propose the following generic scenario, applicable to mixtures of materials with similar diffusion coefficients and surface energies, such as quartz-feldspar, olivine-pyroxene, or calcite-dolomite. 1) Deformation of an initially coarse-grained two-phase aggregate results in grain refinement by dynamic recrystallization, and possibly also by brittle fracture of the stronger phase. Stress concentration in the stronger phase results in a greater degree of grain-size reduction. 2) Grain-size reduction in both phases results in a transition to grain-size sensitive creep, producing alternating bands of relatively weak fine-grained material. 3) Grain-boundary sliding in the finer, strong-phase material is facilitated by grain-boundary diffusion (Coble) creep of the weaker phase. The weaker phase fills the spaces between the strong grains; hence the grain-size of the weaker phase is controlled by that of the stronger phase. This leads to mixing and dispersion of the two phases, producing a fine-grained, evenly dispersed two-phase aggregate, with a grain-size dictated by that of the stronger phase. 3) The rheology of the aggregate will be controlled by the volume concentration of the two phases and their respective individual rheologies, but will be dominated by grain-boundary diffusion creep of the weaker phase. 4) Grain-growth in the mixture is limited by the diffusion coefficient for grain-boundary diffusion of the less abundant phase, as growth of isolated grains requires diffusion along the grain-boundaries. The growth law for the aggregate is slowed relative to that of the single phase by the ratio of grain-boundary length / grain-boundary thickness for the dispersed phase, which is likely to be of the order of 10^5. This therefore provides a mechanism for developing and maintaining strongly weakened zones of two-phase mylonite that will localize deformation.

Platt, J. P.; Behr, W. M.

2012-12-01

274

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

275

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 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

2011-04-01

276

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

277

Rheology and flow analysis fresh concrete. Fresh concrete no rheology to ryudo kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Necessity of rheology has surfaced as a result of wider use of high-strength or high-flow placement-free concrete. This paper introduces researches on techniques to estimate production and workability using a flow analysis that uses as inputs the characteristic values of fresh concrete properties quantified according to the rheology. A simplest model applied to material evaluation is a Bingham model using two constants, the yield value and the plastic viscosity, but even this is still complex if seen from the fact that the conventional models have used softness as the only parameter. Further, proposals have been made on such methods as the two-phase model that considers motions of coarse aggregates individually, the composite model and the flow model under vibration. In the aspect of the rheology test methods, the twist type or shear box type methods have emerged in place of the rotating viscometer. Analytic aspects contain problems under vibration and pulsation, and different calculation methods including the viscoplastic finite element method. The issue is how the methods can be simplified with respect to computer capabilities. 63 refs., 12 figs.

Tanigawa, Y.; Mori, H. (Nagoya University, Nagoya (Japan). Faculty of Engineering)

1993-10-01

278

Structural rheological model of two-phase interlayer shear flow  

Science.gov (United States)

This paper presents a study of an epitropic liquid crystal layer formation at a metal substrate. Such layer structurization leads to non-Newtonian flow of thin interlayer with wall-adjacent orientation-ordered layers. Rheological characteristics of micron interlayers of n-hexadecane and Vaseline oil with surfactant addition are investigated. The features of structural "variable viscosity" layer are defined within the framework of a proposed rheological model. An increase in the rate of shear deformation leads to a reduction in near-surface layer viscosity due to molecular reorientation. Estimation of model parameters, performed on basis of the experimental rheological data, is carried out.

Altoiz, B. A.; Aslanov, S. K.; Kiriyan, S. V.

2011-04-01

279

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

280

Resolvent operator method for solving rheological equations of state  

International Nuclear Information System (INIS)

Fano's tetradic representation of Liouville--Neumann operators is used as the basis of a systematic procedure for solving an important class of rheological equations of state. This procedure is complementary to the techniques which Bird and his co-workers have used in their studies of complicated rheological models. To illustrate how our method works it is applied to a rheological model of the Maxwell--Oldroyd type. Explicit formulas are derived for the stress tensors associated with a number of time-independent, homogeneous flows

1985-03-01

 
 
 
 
281

Rheological characterisation of municipal sludge: a review.  

Science.gov (United States)

Sustainable sludge management is becoming a major issue for wastewater treatment plants due to increasing urban populations and tightening environmental regulations for conventional sludge disposal methods. To address this problem, a good understanding of sludge behaviour is vital to improve and optimize the current state of wastewater treatment operations. This paper provides a review of the recent experimental works in order for researchers to be able to develop a reliable characterization technique for measuring the important properties of sludge such as viscosity, yield stress, thixotropy, and viscoelasticity and to better understand the impact of solids concentrations, temperature, and water content on these properties. In this context, choosing the appropriate rheological model and rheometer is also important. PMID:23899879

Eshtiaghi, Nicky; Markis, Flora; Yap, Shao Dong; Baudez, Jean-Christophe; Slatter, Paul

2013-10-01

282

Rheology of foamy oil in porous media  

Energy Technology Data Exchange (ETDEWEB)

Experiments were undertaken to test the hypothesis that during primary production, the solution gas released from heavy oil does not disengage from the liquid immediately but remains dispersed in the form of micro-bubbles and these adherents reduce the viscosity of the oil. The experiments sought to determine the effects of asphaltenes, dissolved gas content, temperature and bubble sizes on viscosity. Results showed that foamy oil viscosity was independent of shear rate at high pressures, however, a mild non-Newtonian behaviour was observed at low pressures. The viscosity of gas-oil dispersion was found to be inversely proportional to bubble size thus, the smaller the bubbles the higher the viscosity. The rheological behaviour of foamy dispersion was found to be higher than, or similar to the viscosity of live oil. Consequently, the hypothesis of reduced viscosity resulting from adsorption of asphaltenes was not confirmed by experimental evidence. 11 refs., 15 figs.

Bora, R. [Calgary Univ., AB (Canada); Maini, B. B. [Petroleum Recovery Inst., Calgary, AB (Canada); Chakma, A. [Regina Univ., SK (Canada)

1997-12-31

283

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

284

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.

2011-12-01

285

Rheological properties of modified lupin proteins.  

Science.gov (United States)

The properties of acetylated, succinylated and phosphorylated protein isolates extracted from the flour of yellow lupins (L. luteus) were studied by means of oscillatory rheology. The flow behaviour of protein dispersions (15% w/w) and the properties of thermotropic gels were distinctly influenced by the modification. Succinylation increased the viscosity of the dispersions of unmodified protein isolate (LPI) from 99 mPas to 515 mPas and results in the lowest gel point (T = 30.5 degrees C). Acetylation and phosphorylation enhance the pseudoplastic flow behaviour of the dispersions. Acylated lupin samples formed the strongest gels with a small visco-elastic range while phosphorylation leads to weak and "rubber-like" gels. PMID:11712245

Krause, J P; Bagger, C; Schwenke, K D

2001-10-01

286

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

2003-09-07

287

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.)

1988-01-01

288

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.

2011-01-01

289

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.

Varela López, F.; Rosen, M..

290

Rheology of petroleum coke-water slurry  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the results of the studies carried out on the optimization of particle size distribution, the rheological characteristics and stability of highly loaded petroleum coke-water slurry using three additives. The solids loading achieved in the slurries were in the range of 65% to 75.6% depending on the additives used. Slurry viscosity varied between 267 to 424 mPas at 128 s{sup {minus}} shear rate. The petroleum coke-water slurries exhibited pseudoplastic characteristics with yield tending towards Bingham plastic as the solids loading progressively increased. The effect of addition of petroleum coke to the extent of 25% in coal-water slurry prepared from low ash Ledo coal of Makum field in Assam was also examined. The slurry containing coal-petroleum coke blend showed better stability, having shelf life of 7 days as compared to 5 days in the case of petroleum coke-water slurry.

Prasad, M.; Mall, B.K.; Mukherjee, A.; Basu, S.K.; Verma, S.K.; Narasimhan, K.S.

1998-07-01

291

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

Energy Technology Data Exchange (ETDEWEB)

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 LiPF{sub 6} 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{sup -3} S cm{sup -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.

Tian Zheng [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); He Xiangming [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)]. E-mail: hexm@tsinghua.edu.cn; Pu Weihua [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Wan Chunrong [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Jiang Changyin [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

2006-10-25

292

Rheological Characterization of Vegetal Pear (Sechium edule)  

Science.gov (United States)

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

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

2008-07-01

293

Fuel cell having electrolyte inventory control volume  

Energy Technology Data Exchange (ETDEWEB)

The author presents a fuel cell having an electrolyte control volume includes a pair of porous opposed electrodes. A matrix 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 pervious 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, M.K.

1989-08-08

294

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

Science.gov (United States)

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

Felsche, J.

1983-06-01

295

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

296

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

2005-08-30

297

Supercapacitor behavior of ?-MnMoO4 nanorods on different electrolytes  

International Nuclear Information System (INIS)

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

2012-11-01

298

Anion exchange polymer electrolytes  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-23

299

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

Science.gov (United States)

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

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

2014-05-15

300

High elastic modulus polymer electrolytes  

Science.gov (United States)

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

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

2013-10-22

 
 
 
 
301

Electrolytic cell of high voltage  

Energy Technology Data Exchange (ETDEWEB)

An electrolytic cell is described comprising a negative electrode having as the active material a light metal and a positive electrode. As the main active material a poly-dicarbon monofluoride represented by the formula (C/sub 2/F)n has been found to exhibit a high discharge voltage as compared with the conventional electrolytic cell of the type using as the active material of the positive electrode a polycarbon monofluoride represented by the formula (Cf)n and also has been found to be excellent in flatness of discharge voltage and shelf-life. The electrolytic cell of the present invention can be produced at low cost due to high yield of (C2f)n in production, and is useful as the energy source of such devices as watch, clock, desk type computer, small type radio, etc.

Morigaki, K.; Watanabe, N.

1981-01-27

302

Anomalous rheological behavior of long glass fiber reinforced polypropylene  

Science.gov (United States)

Dynamic rheological properties of PP-based long glass fiber-reinforced thermoplastics (LFT) were investigated. Weight fractions of the glass fibers investigated in the present study ranged from 0.15 to 0.5, which are higher than those of previous studies. We observed very abnormal rheological behavior. Complex viscosity (?*) of the LFT increased with the glass fiber content up to 40 wt. %. However, the ?* with a weight fraction of 0.5 is observed to be lower than that of LFT with a weight fraction of 0.4 in spite of higher glass fiber content. From various experiments, we found that this abnormal behavior is analogous to the rheological behavior of a lyotropic liquid crystalline polymer solution and concluded that the abnormal rheological behavior for the LFT is attributed to the formation of a liquid crystal- like structure at high concentrations of long glass fibers.

Kim, Dong Hak; Lee, Young Sil; Son, Younggon

2012-12-01

303

Effect of Particulate Fillers on the Rheology of Polymer Melts.  

Science.gov (United States)

This work focuses in the basic understanding of reinforcement and the relationship between the morphology of the material and its rheological behavior. Mixtures of polydimethylsiloxanes and different fumed silicas were tested under oscillatory shear. The ...

C. W. Macosko E. Mora M. I. Aranguren

1990-01-01

304

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

305

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

306

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

Scientific Electronic Library Online (English)

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

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

307

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

1989-01-01

308

Proton-conducting glass electrolyte.  

Science.gov (United States)

A new porous glass electrolyte consisting of heteropolyacids, i.e., phosphotungstic acid (PWA) and phosphomolybdic acid, was investigated and was found to yield a remarkably high proton conductivity of 1.014 S cm(-1) at 30 degrees C and 85% relative humidity. This is the first time such a high proton conductivity value has been reported for a heteropolyacid glass membrane. The glass was applied as the electrolyte for an H(2)/O(2) fuel cell, and a maximum power density of 41.5 mW/cm(2) at 32 degrees C was attained using this new PWA-containing electrode. PMID:18081259

Uma, Thanganathan; Nogami, Masayuki

2008-01-15

309

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

310

Solid electrolytes: Problems and solutions  

Energy Technology Data Exchange (ETDEWEB)

Degradation phenomena occurring in sodium ..beta..''-alumina solid electrolytes as a consequence of their use in sodium/sulfur batteries are reviewed. Four classes of degradation are discussed: electrolyte reduction, crack propagation, internal sodium precipitation, and reaction with the polysulfide electrode. While degradation reactions may adversely affect cell life, it has been found that these deleterious effects may be avoided by impurity control of the system and by microstructural modification of the ceramic, including grain size control and zirconia-dispersion toughening.

DeJonghe, L.C.

1986-08-01

311

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...

2008-01-01

312

Rheological Properties of Oil in Water Emulsions and Particulate Suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis aims at a better understanding of the rheologicalproperties of the important colloids in oil industry, i.e. suspensions, emulsions and waxes. The rheology of suspension system is a complex field influenced by a large range of variables. In this work, we mainly focused on the rheological properties of suspensions as a function of volume fraction of particles, particle size, surface properties, shear rate, and the nature of continuous mediums. The investigated suspensions behaved as...

Chen, Shukun

2006-01-01

313

Rheology of Carbon Fibre Reinforced Cement-Based Mortar  

Science.gov (United States)

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.

Banfill, Phillip F. G.; Starrs, Gerry; McCarter, W. John

2008-07-01

314

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

2008-07-07

315

Design and application of magneto-rheological fluid  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magneto-Rheological Fluid (MRF) technology is an old “newcomers” coming to the market at high speed. Various industries including the automotive industry are full of potential MRF applications. Magneto-Rheological Fluid technology has been successfully employed already in various low and high volume applications. A structure based on MRF might be the next generation in design for products where power density, accuracy and dynamic performance are the key features. Additionally, for pro...

Olabi, Abdul-ghani; Grunwald, Artur

2007-01-01

316

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. T...

2004-01-01

317

Microstructure, rheology and demixing in emulsions flocculated by polysaccharides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

keywords: Emulsion, b-lactoglobulin, polysaccharides, salt, sucrose, depletion, bridging, percolation, microstructure, micro-rheology, rheology, demixing, creaming, network compression. Abstract In this thesis, a study is presented on gravity-induced demixing behaviour of oil-in-water emulsions, stabilised by b-lactoglobulin and flocculated by various polysaccharides. Flocculation by polysaccharides mainly results in formation of emulsion droplet networks and can proceed via depletion and vi...

Blijdenstein, T. B. J.

2004-01-01

318

Rheological Properties of Oil in Water Emulsions and Particulate Suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis aims at a better understanding of the rheologicalproperties of the important colloids in oil industry, i.e. suspensions, emulsions and waxes.The rheology of suspension system is a complex field influenced by a large range of variables. In this work, we mainly focused on the rheological properties of suspensions as a function of volume fraction of particles, particle size, surface properties, shear rate, and the nature of continuous mediums. The investigated suspensions behaved as ...

Chen, Shukun

2006-01-01

319

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...

2012-01-01

320

Local Rheology of Human Neutrophils Investigated Using Atomic Force Microscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Lee, Yong J.; Patel, Dipika; Park, Soyeun

2011-01-01

 
 
 
 
321

Rheological Characterization of Sludge Coming from a Wastewater Treatment Plant  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem statement: The aim of this study was that of studying the rheology of sewage sludge using two different rheological test protocols taken from literature and comparing them in order to evaluate which useful information are given from every protocol. Approach: Two different protocols have been used taking particularly into account the problems connected to sludge heterogeneous composition and to the interaction between solid-solid and solid-water particles in order to comp...

Daniel Novarino; Ezio Santagata; Davide Dalmazzo; Mariachiara Zanetti

2010-01-01

322

Rheological Study of Genipin Cross-Linked Chitosan Hydrogels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper reports the rheological behavior of chitosan solutions that have been cross-linked with different amounts of genipin, at body temperature and physiological pH. The effect of the cross-linker loading on the rheological properties of hydrogels has been evaluated. The oscillatory time sweep method was used to monitor the dynamic viscoelastic parameters during in situ (i.e., in the rheometer) gelation experiments, enabling the determination of the gelation time. The stress and frequenc...

Moura, M. Jose?; Figueiredo, M. Margarida; Gil, M. Helena

2007-01-01

323

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...

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

2010-01-01

324

Rheological and electrical analysis in carbon nanofibre reinforced polypropylene composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two different types of carbon nanofibers (CNF) were incorporated in the same polypropylene (PP) matrix by twin-screw extrusion. The electrical characterization of both CNFs / PP composites as a function of volume fraction show different electrical performance: conducting and non-conducting. The objective of this work is to study the rheological behaviour of both composites with the aim of relating it to the electrical behaviour. The results indicate that the rheological behavio...

Lanceros-me?ndez, S.; Paleo, A. J.; Silva, J.; Hattum, F. W. J.; Ares, A. I.

2013-01-01

325

Relationship between dynamic recrystallization, grain size distribution and rheology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Heege, Johannes Hendrik Ter

2002-01-01

326

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

1998-01-01

327

Potential Role of Electrolytic Hydrogen in Canada.  

Science.gov (United States)

The potential role of electrolytic hydrogen in Canada is assessed for the period 1980 to 2025 for large-scale uses only. Present uses of hydrogen, and specifically electrolytic hydrogen, are discussed briefly and hydrogen production processes are summariz...

M. Hammerli

1982-01-01

328

Nonlocal granular rheology: Role of pressure and anisotropy  

Science.gov (United States)

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

Wandersman, Elie; van Hecke, Martin

2014-01-01

329

Dispersions of silica nanoparticles in ionic liquids investigated with advanced rheology  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-02-15

330

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

331

Polymer Electrolytes for Lithium/Sulfur Batteries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

332

LOWER TEMPERATURE ELECTROLYTE AND ELECTRODE MATERIALS  

Energy Technology Data Exchange (ETDEWEB)

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

Keqin Huang

2003-04-30

333

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

334

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

335

Novel pseudo-delocalized anions for lithium battery electrolytes.  

Science.gov (United States)

A novel anion concept of pseudo-delocalized anions, anions with distinct positive and negative charge regions, has been studied by a computer aided synthesis using DFT calculations. With the aim to find safer and better performing lithium salts for lithium battery electrolytes two factors have been evaluated: the cation-anion interaction strength via the dissociation reaction LiAn ? Li(+) + An(-) and the anion oxidative stability via a vertical ionisation from anion to radical. Based on our computational results some of these anions have shown promise to perform well as lithium salts for modern lithium batteries and should be interesting synthetic targets for future research. PMID:22441354

Jónsson, Erlendur; Armand, Michel; Johansson, Patrik

2012-05-01

336

Na+ Ion Conducting Hot-pressed Nano Composite Polymer Electrolytes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Synthesis, characterization and polymeric battery studies of Na+ ion conducting Nano- Composite Polymer Electrolyte (NCPE) membranes: (1-x) [75PEO: 25NaPO3]: x SiO2, where x = 0 - 15 wt. (%), has been reported. NCPE membranes have been casted using a novel hot-press technique in place of the traditional solution cast method. The dispersal of SiO2 in SPE host: (75PEO: 25NaPO3), a conductivity enhancement of an order of magnitude achieved in NCPE film: [93 (75PEO: 25NaPO3): 7 SiO2]. This has be...

Angesh Chandra; Archan Chandra; Kiran Thakurb

2012-01-01

337

Proton-conducting electrolyte membranes based on aromatic condensation polymers  

International Nuclear Information System (INIS)

The results of investigations in the field of development and applications of proton-conducting electrolyte membranes based on aromatic condensation polymers are analysed and summarised. Primary attention is paid to the properties of the starting polymers, such as the thermal stability, water uptake and proton conductivity. General approaches to the preparation of aromatic condensation polymers with high proton conductivity are considered, including sulfonation, synthesis from monomers containing sulfonic acid groups, incorporation of alkylsulfonated substituents and formation of acid-basic polymer complexes. The bibliography includes 115 references.

2002-09-30

338

Perovskite solid electrolytes for SOFC.  

Science.gov (United States)

We have synthesized a new series of brownmillerite solid electrolyte phases Ba(sub 2)GdIn(sub 1-x)Ga(sub x)O(sub 5) (x = 0,0.2,0.4) with the x = 0.2 phase exhibiting an unusually low E. relative to both the observed ionic conductivity in this phase and to...

A. F. Sammells

1993-01-01

339

Intermediate temperature electrolytes for SOFC  

Energy Technology Data Exchange (ETDEWEB)

The objective of this work is to identify a new set of materials that would allow the operation of the solid oxide fuel cell in the 600--800{sup degrees}C temperature range. The approach that is being used is to start with a systematic evaluation of new electrolyte materials and then to develop compatible electrode and interconnect materials.

Bloom, I.; Krumpelt, M.; Hash, M.C.; Zebrowski, J.P.; Zurawski, D.

1992-01-01

340

Intermediate temperature electrolytes for SOFC  

Energy Technology Data Exchange (ETDEWEB)

The objective of this work is to identify a new set of materials that would allow the operation of the solid oxide fuel cell in the 600--800{sup degrees}C temperature range. The approach that is being used is to start with a systematic evaluation of new electrolyte materials and then to develop compatible electrode and interconnect materials.

Bloom, I.; Krumpelt, M.; Hash, M.C.; Zebrowski, J.P.; Zurawski, D.

1992-09-01

 
 
 
 
341

Polymer precursors for solid electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Polymer precursors for the solid polymer matrix of a solid electrolyte are acryloyl-derivatized urethane polymers made from isocyanate and a macroglycol of chemically linked blocks of poly(oxyalkylene) and/or polyester units. The linking groups are carbonate, bis-carbonate, phosphate, phosphonate, siloxy and sulfone groups. (author)

Chaloner-Gill, B.; Golovin, M.; Lundquist, J.

1996-07-04

342

Intermediate temperature electrolytes for SOFC  

Science.gov (United States)

The objective of this work is to identify a new set of materials that would allow the operation of the solid oxide fuel cell in the 600-800 C temperature range. The approach that is being used is to start with a systematic evaluation of new electrolyte materials and then to develop compatible electrode and interconnect materials.

Bloom, I.; Krumpelt, M.; Hash, M. C.; Zebrowski, J. P.; Zurawski, D.

343

Solid polymer electrolyte photovoltaic cell  

Energy Technology Data Exchange (ETDEWEB)

Solid photoelectrochemical cells are described based on PEO-KI/I/sub 2/ electrolytes, n-Si/Pt/PPy photoanodes, and conductive tin-oxide glass counter electrodes. The performance of the present devices is limited by a high series resistance in the polymer film. 22 refs.

Skotheim, T.; Lundstrom, I.

1982-04-01

344

Alkali metal crystalline polymer electrolytes  

Science.gov (United States)

Polymer electrolytes have been studied extensively because uniquely they combine ionic conductivity with solid yet flexible mechanical properties, rendering them important for all-solid-state devices including batteries, electrochromic displays and smart windows. For some 30 years, ionic conductivity in polymers was considered to occur only in the amorphous state above Tg. Crystalline polymers were believed to be insulators. This changed with the discovery of Li+ conductivity in crystalline poly(ethylene oxide)6:LiAsF6 (refs 4, 5). However, new crystalline polymer electrolytes have proved elusive, questioning whether the 6:1 complex has particular structural features making it a unique exception to the rule that only amorphous polymers conduct. Here, we demonstrate that ionic conductivity in crystalline polymers is not unique to the 6:1 complex by reporting several new crystalline polymer electrolytes containing different alkali metal salts (Na+, K+ and Rb+), including the best conductor poly(ethylene oxide)8:NaAsF6 discovered so far, with a conductivity 1.5 orders of magnitude higher than poly(ethylene oxide)6:LiAsF6. These are the first crystalline polymer electrolytes with a different composition and structures to that of the 6:1 Li+ complex.

Zhang, Chuhong; Gamble, Stephen; Ainsworth, David; Slawin, Alexandra M. Z.; Andreev, Yuri G.; Bruce, Peter G.

2009-07-01

345

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

346

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

347

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

348

Rheology and Gelling Behavior of Boehmite Sols  

Directory of Open Access Journals (Sweden)

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

Eng-Seng Chan

2011-01-01

349

Moho, seismogenesis, and rheology of the lithosphere  

Science.gov (United States)

The Moho is not always a sharp interface; but seismic phase SsPmp yields robust, physically averaged estimates of crustal thickness (virtual deep seismic sounding, VDSS). In S. Tibet where the Moho is as deep as 75 km, bimodal distribution of earthquake depths, with one peak in the upper crust and the other below the Moho, generated much interest in how lithological contrast affects seismicity and rheology. Generally seismicity is limited by distinct temperatures (Tc): 350 ± 50 °C in the crust and 700 ± 100 °C in the mantle (Earthquake Thermometry). Laboratory experiments show that distinct Tc reflect the onset of substantial crystal plasticity in major crustal and mantle minerals, respectively. Above these Tc, frictional instability ends due to velocity weakening of slip. So the seismic to aseismic transition is closely linked with brittle-ductile transitions in the crust and in the uppermost mantle, where the strength of the continental lithosphere is expected to peak ("Jelly Sandwich"). Plasticity depends exponentially on temperature (which evolves over time), so interplay between the geotherm and crustal thickness could result in concentrated seismicity in the upper crust — the only portion of a very warm lithosphere where temperature is below ~ 350 °C ("Crème Brûlée"). Conversely, where the entire crust is below ~ 350 °C (and the uppermost mantle is also below ~ 700 °C), then earthquakes could occur over a wide range of depths, including the entire crust and the uppermost mantle ("Caramel Slab").

Chen, Wang-Ping; Yu, Chun-Quan; Tseng, Tai-Lin; Yang, Zhaohui; Wang, Chi-yuen; Ning, Jieyuan; Leonard, Tiffany

2013-12-01

350

Rheological studies of thermosensitive triblock copolymer hydrogels.  

Science.gov (United States)

Hydrogel formation by physical cross-linking is a developing area of research toward materials suitable for pharmaceutical and biomedical applications. Polymers exhibiting lower critical solution temperature (LCST) behavior in aqueous solution are used in this study to prepare hydrogels. Four triblock copolymers (ABA) with thermosensitive poly(N-(2-hydroxypropyl) methacrylamide lactate) A-blocks and a hydrophilic poly(ethylene glycol) B-block have been synthesized. The molecular weight of the hydrophilic PEG block was fixed at 10 kDa, whereas the molecular weight of the pHPMAm-lactate block was varied between 10 and 20 kDa. The rheological characteristics of these polymer hydrogels were studied as a function of temperature, concentration, and the length of the thermosensitive blocks. Gelation occurred rapidly upon increasing the temperature to 37 degrees C, which makes this system suitable as an injectable formulation. The gels became stronger with increasing temperature and concentration, and moreover they behaved as critical gels, which means that G' and G' ' follow power laws over the entire frequency range. Surprisingly, with increasing length of the thermosensitive blocks, weaker hydrogels were formed. This trend can be explained by the cross-link density of the physical network, which increases with decreasing length of the thermosensitive blocks. PMID:17107019

Vermonden, Tina; M, Nicolaas A; van, Mies J; Hennink, Wim E

2006-11-21

351

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

352

Rheological Properties of Barley and Flaxseed Composites  

Directory of Open Access Journals (Sweden)

Full Text Available The newly developed barley-flaxseed composites were unique because barley provides the soluble fiber ?-glucan that is beneficial for improving food texture and preventing coronary heart disease along with the health benefits of omega-3 polyunsaturated fatty acids (w-3 PUFAs of flaxseed. The new composites of barley with flaxseeds were prepared using prowashonupana, a barley variety containing high ?-glucan content, with 10, 20, and 50% flaxseed for enhancing health benefits of functional food. Besides the nutritional aspects of barley-flaxseed composites, they have improved water holding capacities, texture, and useful pasting and viscoelastic qualities measured using a Rapid Visco Analyzer (RVA followed by an advanced rheometer. The pasting and rheological properties of the barley flour were not greatly influenced by 10% ground flaxseed replacements but showed differences at the 50% replacement level. Shear thinning properties were observed for all the composites. These functional composites could be valuable and applicable for developing new functional food products with health benefits of decreasing heart problems, diabetes, and obesity along with providing desirable texture.

George. E. Inglett

2013-01-01

353

Rheological properties of asphalts with particulate additives  

Energy Technology Data Exchange (ETDEWEB)

The Superpave asphalt binder specifications are performance-based specifications for purchasing asphalt binders for the construction of roads. This means that the asphalt is characterized by fundamental material (rheological) properties that relate to the distress modes of the pavements. The distress modes addressed are primarily rutting, fatigue cracking and low temperature cracking. For example, G*/sin({delta}) is designed to predict the rutting potential of pavements, where G* is the magnitude of the complex shear modulus and 6 is the phase angle. The binder for a road that is situated in a certain climatic zone requires the binder to have a minimum G*/sin({delta}) of 2200 Pa at the highest consecutive 7-day average pavement temperature the road had experienced. Implicit in such a performance based specification is that the fundamental property, G*/sin({delta}), of the binder correlates with rutting potential of the pavement regardless of the nature of the binder. In other words, the specification is transparent to the fact that the binder can simply be an asphalt, or an asphalt modified by polymers, particulates and other materials that can form a two-phase mixture. This paper discusses the asphalt-particulate system.

Shashidhar, N. [EBA Engineering, Baltimore, MD (United States); Chollar, B.H. [Federal Highway Administration, McLean, VA (United States)

1996-12-31

354

Effects of ioxaglate to blood rheology  

Energy Technology Data Exchange (ETDEWEB)

Almen and Aspelin have shown that the use of non-ionic radio contrast media allows to increase the iodine concentration (which is desirable because of its effect on radio opacity) without a very large increase in osmolarity (which is undesirable because it impairs the fluidity of erythrocytes). This latter effect can also be diminished by reducing the osmolarity of a dimeric contrast medium as it has been achieved by incorporating more iodine atoms into the molecule in the case of ioxaglate (Hexabrix). In various microrheological test systems, the fluidity of packed red cell suspension, the corrected filtration rate though 5 ..mu..m pores and the relative apparent viscosity of blood - contrast media mixtures (1 to 50% concentration) were determined in experiments comparing this compound with Urografin 76 of the same iodine content. In all systems, the former showed lesser rheological effects. In whole blood viscometry, this can be detected only after appropriate corrections for the effects of the two contrast media on hematocrit and plasma viscosity. Owing to a more pronounced water shift from the cells to the plasma, Urografin tends to reduce the viscosity of the plasma-contrast media mixture. The concomitant reduction in MCV and hematocrit level tends to screen the macrorheological effect of the dehydrated cells becomes immediately obvious when the viscometric data are corrected for hematocrit value and plasma viscosity effects.

Schmid-Schoenbein, H.; Teitel, P.; Tietz, G.; Oezlen, A.

1984-10-01

355

Haemostatical and rheological aspects of dysfibrinogenemia.  

Science.gov (United States)

Congenital dysfibrinogenemia is based on different alterations in the structure of the fibrinogen molecule leading to a variety of disturbances in the clotting process. Clinical manifestations of the disorder are showing a wide range from asymptomatic states to mild bleeding diathesis as well as thrombotic complications. In this study two of the 14 patients with dysfibrinogenemia showed a history of mild bleeding while the others showed no clinical symptoms. As fibrinogen is also an important factor of the blood fluidity not only haemostatic but also rheological parameters were measured. Included in the study were 14 patients with ascertained dysfibrinogenemia in comparison to 11 non-affected relatives and a control group of 297 apparently healthy subjects. Plasma viscosity (p < 0.0001) and erythrocyte aggregation index (p < 0.00001) were significantly higher in the patients than in their healthy relatives and the control group. A pathologically increased erythrocyte aggregation was found in 10 of the 14 patients but only in 1 of the 10 relatives. The dysfunction of the fibrinogen molecule thus influences the aggregation process of the red blood cells to a greater extent than normal fibrinogen. Moreover, there seems to be a stronger influence of the dysfunctional fibrinogen molecule on the aggregation process than on plasma viscosity. To date the question if the enhanced erythrocyte aggregation in dysfibrinogenemic patients may be of any diagnostic interest and if there are significant differences between patients with bleeding diathesis and thrombophilia cannot be answered and remains to be cleared in further investigations. PMID:9181754

Mörsdorf, S; Jung, F; Seyfert, U T; Mrowietz, C; Pindur, G; Wenzel, E

1997-01-01

356

Rheology of microsphere formation and refinement  

International Nuclear Information System (INIS)

Two important steps in the fabrication of microsphere laser fusion targets have been analyzed by simple mathematical modeling. Volatile-containing droplets emerging from a nozzle with imposed oscillation first undergo a spontaneous blowing process, driven by the evaporation of volatile solvent which pushes the polymeric shell outward. These hollow particles then enter a refinement zone, where a centering process takes place to eliminate eccentricity between the shell internal and external surfaces. The confined vapor partially permeates to the surroundings, allowing shrinkage of the microspheres in this zone to the desired final dimensions and sphericity. Biaxial extensional flow dominates the rheology of micropshere expansion, whereas detailed dynamics of radial flow results in improved concentricity and sphericity. The effects of viscoelasticity on the rate and stress associated with microsphere expansion have been studied using the Newtonian and Maxwell constitutive equations. Simple analytic results to describe microsphere refinement have been obtained for conditions representative of the centering process where Newtonian behavior prevails as the fluid flow is relatively weak

1986-04-01

357

Foam structure and rheology in thin gaps.  

Energy Technology Data Exchange (ETDEWEB)

The cell structure and rheology of gas-liquid foams confined between parallel plates depend on the ratio H/R, where H is the plate spacing and R is the (equivalent spherical) bubble radius. We consider ordered three-dimensional foams that consist of 1-3 layers of bubbles. In the 'dry' limit, where the gas fraction is unity, one confined layer is composed of hexagonal cylinders; two layers contain Fejes Toth cells; and three or more layers are modeled as Kelvin cells sandwiched between Fejes Toth cells. We also consider wet foams where all of the liquid is assumed to be located in either conventional Plateau borders or wall Plateau borders adjacent to the plates. The Surface Evolver is used to calculate the foam structure and stress as a function of H/R, which enables us to evaluate elastic behavior. A relationship between the two-dimensional structure at the wall and bubble size has application to foam characterization.

Reinelt, Douglas A. (Southern Methodist University, Dallas, TX); Kraynik, Andrew Michael

2008-04-01

358

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

359

Effects of ioxaglate to blood rheology  

International Nuclear Information System (INIS)

Almen and Aspelin have shown that the use of non-ionic radio contrast media allows to increase the iodine concentration (which is desirable because of its effect on radio opacity) without a very large increase in osmolarity (which is undesirable because it impaires the fluidity of erythrocytes). This latter effect can also be diminished by reducing the osmolarity of a dimeric contrast medium as it has been achieved by incorporating more iodine atoms into the molecule in the case of Ioxaglate (Hexabrix). In various microrheological test systems, the fluidity of packed red cell suspension, the corrected filtration rate though 5 ?m pores and the relative apparent viscosity of blood - contrast media mixtures (1 to 50% concentration) were determined in experiments comparing this compound with Urografin 76 of the same iodine content. In all systems, the former showed lesser rheological effects. In whole blood viscometry, this can be detected only after appropriate corrections for the effects of the two contrast media on hematocrit and plasma viscosity. Owing to a more pronounced water shift from the cells to the plasma, Urografin tends to reduce the viscosity of the plasma-contrast media mixture. The concomitant reduction in MCV and hematocrit level tends to screen the macrorheological effect of the dehydrated cells becomes immediately obvious when the viscometric data are corrected for hematocrit value and plasma viscosity effects. (orig.)

1984-10-01

360

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

 
 
 
 
361

Electrolyte measurement device and measurement procedure  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-01-26

362

Synthesis and characterization of Ba0.6Sr0.4Ce0.8?xZrxY0.2O3?? proton-conducting oxides for use as fuel cell electrolyte  

International Nuclear Information System (INIS)

Highlights: • The proton-conducting oxides are successfully prepared using a sol–gel process. • Increasing the Zr content causes lattice constriction of the perovskite structure. • Increasing the Ce/Zr ratio in the oxides increased ionic conductivity. • The Zr-free Ba0.6Sr0.4Ce0.8Y0.2O3?? is unstable in a CO2 atmosphere at 600 °C. • Suitable substitution of Ce with Zr greatly improves the oxide chemical stability. -- Abstract: Ba0.6Sr0.4Ce0.8?xZrxY0.2O3?? (x = 0–0.8) proton-conducting oxides are prepared using a sol–gel complexing process. The effects of the Ce/Zr ratio on various material properties are systematically investigated. The sintered samples show a perovskite crystal structure without impurity phases and have a rather compact interior, making them suitable for use as a fuel cell electrolyte. Increasing the Zr content in the oxides causes lattice constriction and suppresses grain growth during sintering at 1600 °C. The ionic conductivity of the oxides increases with increasing Ce/Zr ratio. At 800 °C, Ba0.6Sr0.4Ce0.8Y0.2O3?? has a conductivity of as high as 0.14 S/cm. However, X-ray diffraction and Raman spectroscopy evaluations show that this oxide cannot withstand a CO2 atmosphere. A suitable substitution of Ce with Zr in the structure significantly improves the chemical stability of the oxide without significantly degrading conductivity

2014-02-15

363

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: {center_dot} Synthesis of a dimeric ionic liquid. {center_dot} Gel polymer electrolytes providing uniform lithium deposit pathway. {center_dot} An amphipathic ionic liquid locates at the interface between an electrolyte-rich phase and a polymer matrix in a gel polymer electrolyte. {center_dot} 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 {sup 1}H 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.

Choi, Nam-Soon, E-mail: nschoi@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Koo, Bonjae; Yeon, Jin-Tak [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Lee, Kyu Tae, E-mail: ktlee@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Kim, Dong-Won [Department of Chemical Engineering, Hanyang University, Seungdong-Gu, Seoul 133-791 (Korea, Republic of)

2011-08-30

364

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.

2011-08-30

365

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

366

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

International Nuclear Information System (INIS)

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 Edta4- 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.

2012-01-15

367

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

368

Determination of rheological properties using hybrid optimisation method  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is description of special software developed for identification of parameters values of rheological models used by ProCAST package for simulation of state of stress in the solidifying castings.Design/methodology/approach: The PyTensionTest uses a hybrid optimization algorithm. This algorithm includes the stochastic method which searches the starting point for direct search optimization method. The identification of parameters values is based on measurement results obtained within the confines of the material tests carried out using the testing machine.Findings: This paper presents the results of approximation of stress-strain relationship for two grades of steel using the elasto-plastic rheological model with power law hardening where its parameters are linearly dependent on temperature.Research limitations/implications: This paper presents the special software that allows user to define any rheological model.Practical implications: Application of obtained values of rheological parameters in the ProCAST software allows to determine stress and strain distribution in continuous castings. It can help to optimize important process parameters.Originality/value: Developed software can approximate the results of static tension tests using rheological model depended on material temperature. This software makes possible an approximation of several stressstrain curves simultaneously. Application of the hybrid optimization method allows to obtain very precise approximation due to determination of the global minimum of the goal function.

B. Foder

2012-12-01

369

Rheological properties of crumb rubber modified bitumen containing antioxidant  

International Nuclear Information System (INIS)

Rheology has become a useful tool in the characterization of the bitumen performance on the pavement. Visco-elastic properties of crumb rubber modified bitumen with antioxidants (CR30) were determined by the means of rheological measurement. This measurement led to a better knowledge of bitumen behavior that occurs when subjected to different thermal and mechanical conditions, as seen during road construction and services in the field. Dynamic Shear Rheometer (DSR) was used to characterize the rheology of the binders before and after oven aging. The binders were aged for 3 and 9 days. Results of a compatibility test showed that the addition of CR30 modified bitumen is compatible with the base bitumen. The results of unaged samples indicated that the addition of 1% CR30 and 5% CR30 modified binders caused an increase in G value as a result of the rheological changes. Results showed that aging has significant influence on bitumen rheology, by increasing complex modulus and decreasing phase angle. (author)

2009-01-01

370

Composite electrode/electrolyte structure  

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-01-27

371

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

372

New Polymer Electrolyte Cell Systems  

Science.gov (United States)

PAPERS PUBLISHED: 1. Pappenfus, Ted M.; Henderson, Wesley A.; Owens, Boone B.; Mann, Kent R.; Smyrl, William H. Complexes of Lithium Imide Salts with Tetraglyme and Their Polyelectrolyte Composite Materials. Journal of the Electrochemical Society (2004), 15 1 (2), A209-A2 15. 2. Pappenfus, Ted M.; Henderson, Wesley A.; Owens, Boone B.; Mann, Kent R.; Smyrl, William H. Ionic-liquidlpolymer electrolyte composite materials for electrochemical device applications. Polymeric Materials Science and Engineering (2003), 88 302. 3. Pappenfus, Ted R.; Henderson, Wesley A.; Owens, Boone B.; Mann, Kent R.; and Smyrl, William H. Ionic Conductivity of a poly(vinylpyridinium)/Silver Iodide Solid Polymer Electrolyte System. Solid State Ionics (in press 2004). 4. Pappenfus Ted M.; Mann, Kent R; Smyrl, William H. Polyelectrolyte Composite Materials with LiPFs and Tetraglyme. Electrochemical and Solid State Letters, (2004), 7(8), A254.

Smyrl, William H.; Owens, Boone B.; Mann, Kent; Pappenfus, T.; Henderson, W.

2004-01-01

373

Perovskite solid electrolytes for SOFC  

Energy Technology Data Exchange (ETDEWEB)

We have synthesized a new series of brownmillerite solid electrolyte phases Ba{sub 2}GdIn{sub 1-x}Ga{sub x}O{sub 5} (x = 0,0.2,0.4) with the x = 0.2 phase exhibiting an unusually low E. relative to both the observed ionic conductivity in this phase and to E{sub a}s observed in similar compounds. We attribute measured ionic conductivities to a lack of available charge carriers in Ba{sub 2}GdIn{sub 0.8}Ga{sub 0.2}O{sub 5}. However, the low E{sub a} supports the premise that brownmillerite solid electrolyte structures are suitable for supporting high ionic conductivity. Current work is focusing on enhancing the amount of charge carriers in these materials by systematically introducing disorder into the brownmillerite lattice.

Sammells, A.F.

1993-11-01

374

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

2002-07-13

375

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

376

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

377

Perovskite solid electrolytes for SOFC  

Energy Technology Data Exchange (ETDEWEB)

Selected perovskite solid electrolytes incorporated into research size fuel cells have shown stability for > 4000 hours at 600{degrees}C. Perovskite lattice requirements which favor low E{sub a} for ionic conduction include (i) that the perovskite lattice possess a moderate enthalpy of formation, (ii) perovskite lattice possess large free volumes, (iii) that the lattice minimally polarizes the mobile ion and (iv) that the crystallographic saddle point r{sub c} for ionic conduction is {approx_equal} 1.

Sammells, A.F.

1992-09-01

378

Perovskite solid electrolytes for SOFC  

Energy Technology Data Exchange (ETDEWEB)

Selected perovskite solid electrolytes incorporated into research size fuel cells have shown stability for > 4000 hours at 600{degrees}C. Perovskite lattice requirements which favor low E{sub a} for ionic conduction include (i) that the perovskite lattice possess a moderate enthalpy of formation, (ii) perovskite lattice possess large free volumes, (iii) that the lattice minimally polarizes the mobile ion and (iv) that the crystallographic saddle point r{sub c} for ionic conduction is {approx equal} 1.

Sammells, A.F.

1992-01-01

379

2012 SRNL-EM VANE RHEOLOGY RESULTS  

Energy Technology Data Exchange (ETDEWEB)

The vane method has been shown to be an effective tool in measuring the yield stress of both settled and mixed slurries in laboratory bench scale conditions in supporting assessments of both actual and simulant waste slurries. The vane has also been used to characterize dry powders and granular solids, the effect of non-cohesive solids with interstitial fluids and used as a guide to determine if slip is present in the geometries typically used to perform rheological flow curve measurements. The vane has been extensively characterized for measuring the shear strength in soils in both field and laboratory studies. The objectives for this task are: Fabricate vane instrument; Bench top testing to further characterize the effect of cohesive, non-cohesive, and blends of cohesive/non-cohesive simple simulants; Data from measurement of homogenized and settled bed of Kaolin sludge and assessment of the technology. In this document, the assessment using bench scale measurements of non-cohesive materials (beads) and cohesive materials (kaolin) is discussed. The non-cohesive materials include various size beads and the vane was assessed for depth and deaeration (or packing) via tapping measurements. For the cohesive (or non-Newtonian) materials, flow curves and yield stress measurements are performed using the vane and this data is compared to the traditional concentric cylinder flow curve measurement. Finally, a large scale vane was designed, fabricated, and tested with the cohesive (or non-Newtonian) materials to determine how a larger vane performs in measuring the yield stress and flow curve of settled cohesive solids.

Hansen, E.; Marzolf, A.; Hera, K.

2012-08-31

380

Coating Of Model Rheological Fluids In Microchannels  

Science.gov (United States)

Researchers have strived to understand and quantify the dynamics within the myriad micro/nano-devices proposed and developed within the last decade. Concepts such as fluid flow, mass transfer, molecule manipulation, and reaction kinetics must be understood in order to intelligently design and operate these devices. In addition to general engineering principles, intelligent design should also focus on material properties (e.g. density, viscosity, conductivity). One key property, viscosity, will play a large part of any fluidic device, including biomedical devices, because the fluids used will, most likely, be non-Newtonian and therefore highly dependent upon the shear rate. Be it a biomedical or macromolecule separation device, or simply the processing of polymeric material, select model polymers and simple flow schemes can be used to investigate the dynamics within micro-devices. Here, we present results for the processing of Newtonian and non-Newtonian polymeric fluids in micro-channels during two-phase penetrating flow. The system investigated is a circular capillary 100 microns in diameter, which is pre-filled with a polymeric liquid. The polymeric liquid is either of Newtonian viscosity, or the same liquid with dispersed high molecular weight polystyrene, which exhibits viscoelastic behavior. A second, immiscible phase, silicone oil of low Newtonian viscosity, is pumped into the system and subsequently cores the polymeric liquid. The dynamics of bubble flow (e.g. bubble velocity and bubble shape) as well as the influence of rheology on coating will be investigated. By studying these model systems, we will learn how complex fluids behave on progressively smaller size scales.

Koelling, Kurt; Boehm, Michael

2008-07-01

 
 
 
 
381

Degradation phenomena in solid electrolytes  

Science.gov (United States)

The critical current density above which degradation occurs in beta-alumina was determined by means of acoustic emissions tests on sodium/sulfur cells. Cells were tested by passing a current which increased linearly with time, as the stress or strain is increased in mechanical testing. The critical current density was found to depend on the rate of increase of the current density, indicating that some type of time dependent degradation is occurring. Microstructural investigation of used electrolytes showed some dissolution of electrolyte from inside cracks, and some used electrolytes had a degraded layer on the sodium exit surface, again indicating some type of time dependent attack. The degradation is attributed to mechanical cracking due to Poiseuille pressure as sodium flows out of surface flaws during charging at high current density. At low current density, long time chemical attack due to changes in the composition of the sodium electrode becomes important. Crack velocity as a function of crack length and current density is estimated for this stress corrosion.

Hitchcock, D. C.

1984-11-01

382

Identification of rheological parameters describing the physico-chemical properties of anaerobic sulphidogenic sludge suspensions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work determined rheological parameters able to describe the rheological properties of the flocculant sludge presents in sulphidogenic anaerobic bioreactors, i.e. a MBR (membrane bioreactor) and a CSTR (continuous stirred tank reactor). Both sludges displayed a non-Newtonian rheological behaviour with shear thinning properties, slightly thixotropic for a TSS content ranging from 0 to 23 g l¿1. Both sulphidogenic sludges displayed pseudoplastic properties. To predict the rheological prope...

Pevere, A.; Guibaud, G.; Hullebusch, E. D.; Lens, P. N. L.

2007-01-01

383

Kinetic characterization of non-linear soft-glassy rheology  

CERN Multimedia

Based on numerical simulations of a lattice kinetic model for soft-glassy materials, we characterize the global rheology of a dense emulsion-like system, under three representative load conditions: Couette flow, time-oscillating Couette flow and Kolmogorov flow. In all cases, it is found that the rheology is described by a Herschel-Bulkley (HB) relation, $\\sigma = {\\sigma}_{Y} + A S^{\\beta}$, with the yield stress ${\\sigma}_{Y}$ largely independent of the loading scenario. Under a proper rescaling of the HB parameters, we can also describe the local rheological behavior, which turns out to be different from the global one because of the spatial heterogeneities. Our analysis illuminates the crucial role of numerical simulations in allowing a seamless exploration of different loading scenarios and enabling measurements of local energy transfer within the flowing material.

Benzi, R; Sbragaglia, M; Succi, S

2013-01-01

384

Rheological Characterization of Unusual DWPF Slurry Samples (U)  

Energy Technology Data Exchange (ETDEWEB)

A study was undertaken to identify and clarify examples of unusual rheological behavior in Defense Waste Processing Facility (DWPF) simulant slurry samples. Identification was accomplished by reviewing sludge, Sludge Receipt and Adjustment Tank (SRAT) product, and Slurry Mix Evaporator (SME) product simulant rheological results from the prior year. Clarification of unusual rheological behavior was achieved by developing and implementing new measurement techniques. Development of these new methods is covered in a separate report, WSRC-TR-2004-00334. This report includes a review of recent literature on unusual rheological behavior, followed by a summary of the rheological measurement results obtained on a set of unusual simulant samples. Shifts in rheological behavior of slurries as the wt. % total solids changed have been observed in numerous systems. The main finding of the experimental work was that the various unusual DWPF simulant slurry samples exhibit some degree of time dependent behavior. When a given shear rate is applied to a sample, the apparent viscosity of the slurry changes with time rather than remaining constant. These unusual simulant samples are more rheologically complex than Newtonian liquids or more simple slurries, neither of which shows significant time dependence. The study concludes that the unusual rheological behavior that has been observed is being caused by time dependent rheological properties in the slurries being measured. Most of the changes are due to the effect of time under shear, but SB3 SME products were also changing properties while stored in sample bottles. The most likely source of this shear-related time dependence for sludge is in the simulant preparation. More than a single source of time dependence was inferred for the simulant SME product slurries based on the range of phenomena observed. Rheological property changes were observed on the time-scale of a single measurement (minutes) as well as on a time scale of hours to weeks. The unusual shape of the slurry flow curves was not an artifact of the rheometric measurement. Adjusting the user-specified parameters in the rheometer measurement jobs can alter the shape of the flow curve of these time dependent samples, but this was not causing the unusual behavior. Variations in the measurement parameters caused the time dependence of a given slurry to manifest at different rates. The premise of the controlled shear rate flow curve measurement is that the dynamic response of the sample to a change in shear rate is nearly instantaneous. When this is the case, the data can be fitted to a time independent rheological equation, such as the Bingham plastic model. In those cases where this does not happen, interpretation of the data is difficult. Fitting time dependent data to time independent rheological equations, such as the Bingham plastic model, is also not appropriate.

Koopman, D. C.

2005-09-01

385

Molecular rheological analysis on binary blends of perfluoropolyether lubricants  

Science.gov (United States)

The molecular rheology of PFPE becomes critically important in designing optimal lubricants that control the friction/wear and air-bearing by tuning elastic or viscous shear/elongation deformations, which affect the performance and reliability of the hard disk drive. In this paper, we examine the rheological responses of nano blended PFPEs including storage (elastic) and loss (viscous) moduli (G' and G?), by monitoring the time-dependent-stress-strain relationship via non-equilibrium molecular dynamics simulations. By introducing binary blend of nonfunctional and functional PFPEs, we control the degree of liquid/solid-like behavior using the rheology as a complementary tool for design criteria by tuning molecular conformation and diffusion with nano blend ratio.

Seung Chung, Pil; Hari, Sesha; Sejoon Park, Vemuri; Jhon, Myung S.

2014-05-01

386

Rheological and microbiological study of flour treated by irradiation  

International Nuclear Information System (INIS)

the aim this work is to study the effectiveness of radio treatment and its effect on the conservation of flour and their various parameters (physico-chemical and rheological). The flour has been treated with different doses (0, 0.75, 1.5 and 3 kGy), physico-chemical, rheological, microbiological and sensory analyses were made.The results show that the irradiation as a treatment for decontamination gave a highly effective. Indeed, a dose of 1.5 kGy allows a total destruction of yeasts and molds. Thus, from the point of view physico-chemical, increasing the dose of radiation causes a change in physical and chemical properties and rheological of flour. for the characteristics of bread, increasing the dose of radiation affects the quality of bread. (Author). 38 refs

2007-01-01

387

Rheological behavior of magnetic powder mixtures for magnetic PIM  

Science.gov (United States)

Powder injection molding (PIM) is a promising manufacturing technology for the net-shape production of small, complex, and precise metal or ceramic components. In order to manufacture high quality magnets using PIM, the magneto-rheological (MR) properties of the PIM feedstock, i.e. magnetic powder-binder mixture, should be investigated experimentally and theoretically. The current research aims at comprehensive understanding of the rheological characteristics of the PIM feedstock. The feedstock used in the experiment consists of strontium ferrite powder and paraffin wax. Steady and oscillatory shear tests have been carried out using a plate-and-plate rheometer, under the influence of a uniform magnetic field applied externally. Rheological properties of the PIM feedstock have been measured and characterized for various conditions by changing the temperature, the powder fraction and the magnetic flux density.

Kim, Sung Hun; Kim, See Jo; Park, Seong Jin; Mun, Jun Ho; Kang, Tae Gon; Park, Jang Min

2012-06-01

388

A rheological approach to analyze aerobic granular sludge.  

Science.gov (United States)

Aerobic granular sludge is one promising biotechnology in wastewater treatment. Despite intensive researches on granular architecture and strategies to improve treatment efficiency, there are still some elusive material parameters needed to stimulate the granulation process. The main aim of this study was to evaluate aerobic granular sludge innovatively using the universal rheology methodology, in terms of processability or quality and texture. Steady shear and oscillatory measurements were performed. Basic rheological characterization showed that aerobic granular sludge was a shear-thinning Herschel-Bulkley fluid with yield pseudoplasticity. Meanwhile, granular sludge presented characterized viscoelastic behaviors in dynamic sweeps highlighting its superiority to flocculent sludge. Furthermore, a Wagner-type constitutive model incorporating a relaxation and damping function was introduced and able to describe the time-dependent and non-linear viscoelastic behaviors. This study could make a further step on predicting rheological properties, helping improve the actual sludge treatment process and the operation of sludge dewatering. PMID:24374128

Ma, Yun-Jie; Xia, Cheng-Wang; Yang, Hai-Yang; Zeng, Raymond J

2014-03-01

389

Hidden Invariants in Rheology: The Persistent Granular Nature of Liquids  

CERN Document Server

It is shown that the deviator, D$_{ij}$, after the process of symmetrization, is not sufficient to completely characterize all the nonrotational information that is contained in the first order flow and, therefore, this information is also lacking in many of the invariant based approaches to rheology based upon it. We recover it through an analysis of the discrete processes that must underlie deformation driven mixing in highly correlated fluids. This allows us to make an intrinsic distinction between pure shear and extension that has implications both for rheology and nonturbulent mixing. In particular, this gives an unambiguous microscopic notion of the rotation rate for every parcel and yields a more general class of invariant rheological theories. We discuss some implications of higher order flows on solutions and suspensions including possibilities for driving and stabilization nonuniform distributions using hydrodynamic forces alone.

Chafin, Clifford

2014-01-01

390

Rheological behaviour of suspensions of bubbles in yield stress fluids  

CERN Multimedia

The rheological properties of suspensions of bubbles in yield stress fluids are investigated through experiments on model systems made of monodisperse bubbles dispersed in concentrated emulsions. Thanks to this highly tunable system, the bubble size and the rheological properties of the suspending yield stress fluid are varied over a wide range. We show that the macroscopic response under shear of the suspensions depends on the gas volume fraction and the bubble stiffness in the suspending fluid. This relative stiffness can be quantified through capillary numbers comparing the capillary pressure to stress scales associated with the rheological properties of the suspending fluid. We demonstrate that those capillary numbers govern the decrease of the elastic and loss moduli, the absence of variation of the yield stress and the increase of the consistency with the gas volume fraction, for the investigated range of capillary numbers. Micro-mechanical estimates are consistent with the experimental data and provide...

Ducloué, Lucie; Goyon, Julie; Chateau, Xavier; Ovarlez, Guillaume

2014-01-01

391

Dielectric Relaxation and Rheological Behavior of Supramolecular Polymeric Liquid  

Energy Technology Data Exchange (ETDEWEB)

A model self-complementary supramolecular polymer based on thymine and diamidopyridine triple hydrogen-bonding motifs has been synthesized, and its dielectric and rheological behavior has been investigated. The formation of supramolecular polymers has been unequivocally demonstrated by nuclear magnetic resonance, electrospray ionization mass spectrometry with traveling wave ion mobility separation, dielectric spectroscopy, and rheology. The dynamical behaviors of this associating polymer generally conform to those of type-A polymers, with a low-frequency chain relaxation and a high-frequency relaxation visible in both rheological and dielectric measurements. The dielectric chain relaxation shows the ideal symmetric Debye-like shape, resembling the peculiar features of hydrogen-bonding monoalcohols. Detailed analysis shows that there exists a weak decoupling between the mechanical terminal relaxation and dielectric Debye-like relaxation. The origin of the Debye-like dielectric relaxation is further discussed in the light of monoalcohols.

Lou, Nan [Shanghai Jiao Tong University, China; Wang, Yangyang [ORNL; Li, Xiaopeng [University of Akron, Akron, Ohio; Li, Haixia [Shanghai Jiao Tong University, Shanghai China; Wang, Ping [Dow Chemicals Company Limited, Shanghai China

2013-01-01

392

Rheology of Semiflexible Bundle Networks with Transient Linkers  

Science.gov (United States)

We present a theoretical and computational analysis of the rheology of networks made up of bundles of semiflexible filaments bound by transient cross-linkers. Such systems are ubiquitous in the cytoskeleton and can be formed in vitro using filamentous actin and various cross-linkers. We find that their high-frequency rheology is characterized by a scaling behavior that is quite distinct from that of networks of the well-studied single semiflexible filaments. This regime can be understood theoretically in terms of a length-scale-dependent bending modulus for bundles. Next, we observe new dissipative dynamics associated with the shear-induced disruption of the network at intermediate frequencies. Finally, at low frequencies, we encounter a region of non-Newtonian rheology characterized by power-law scaling. This regime is dominated by bundle dissolution and large-scale rearrangements of the network driven by equilibrium thermal fluctuations.

Müller, Kei W.; Bruinsma, Robijn F.; Lieleg, Oliver; Bausch, Andreas R.; Wall, Wolfgang A.; Levine, Alex J.

2014-06-01

393

A dynamic rheological model for thin-film lubrication  

International Nuclear Information System (INIS)

In this study, the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated. The thin-film lubrication regime typically appears in Stribeck curves with a clearly observable minimum coefficient of friction (COF) and a low-COF region, which is desired for its lower energy dissipation. A dynamic rheology of the lubricant from the hydrodynamic lubrication regime to the thin-film lubrication regime was proposed based on the convected Maxwell constitutive equation. This rheology model includes the increased relaxation time and the yield stress of the confined lubricant thin film, as well as their dependences on the lubricant film thickness. The Deborah number (De number) was adopted to describe the liquid-solid transition of the confined lubricant thin film under shearing. Then a series of Stribeck curves were calculated based on Tichy's extended lubrication equations with a perturbation of the De number. The results show that the minimum COF points in the Stribeck curve correspond to a critical De number of 1.0, indicating a liquid-to-solid transition of the confined lubricant film. Furthermore, the two proposed parameters in the dynamic rheological model, namely negative slipping length b (indicating the lubricant interfacial effect) and the characteristic relaxation time ?0, were found to determine the minimum COF and the width of the low-COF region, both of which were required to optimize the shape of the Stribeck curve. The developed dynamic rheological model interprets the correlation between the rheological and interfacial properties of lubricant and its lubrication behavior in the thin-film regime. (condensed matter: structural, mechanical, and thermal properties)

2013-01-01

394

Nonlocal Rheology of Granular Flows across Yield Conditions  

Science.gov (United States)

The rheology of dense granular flows is studied numerically in a shear cell controlled at constant pressure and shear stress, confined between two granular shear flows. We show that a liquid state can be achieved even far below the yield stress, whose flow can be described with the same rheology as above the yield stress. A nonlocal constitutive relation is derived from dimensional analysis through a gradient expansion and calibrated using the spatial relaxation of velocity profiles observed under homogeneous stresses. Both for frictional and frictionless grains, the relaxation length is found to diverge as the inverse square root of the distance to the yield point, on both sides of that point.

Bouzid, Mehdi; Trulsson, Martin; Claudin, Philippe; Clément, Eric; Andreotti, Bruno

2013-12-01

395

Vane shear and rheological measurement of estuarine muds  

Energy Technology Data Exchange (ETDEWEB)

The principle aim of the present study is to determine the correlation of the yield stress of cohesive intertidal sediments measured with a field vane shear instrument with laboratory rheological measurements. The secondary aim is the correlation of soils consistency measurements (liquid limit, plastic limit and plasticity index) with rheological measurements. This information can be used to assist interpretation of field vane shear and consistency measurements when the erodibility of cohesive sediments is considered, and will highlight areas worthy of more detailed investigation. Cohesive sediments from the Severn and Mersey estuaries in the United Kingdom were studied. (author).

James, A.E.; Stone, S.J.

1990-01-01

396

Rheological fluid motion in tube by metachronal wave of cilia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this paper is a theoretical study of a non-linear problem of rheological fluid transport in an axisymmetric tube by cilium. However, an attempt has been made to explain the role of cilia motion on the transport of fluid through the ductus efferentes of the male reproductive tract. Ostwald-de Waele power law viscous fluid has been considered to represent the rheological fluid to analyze pumping by means of a sequence of beat of cilia from row to row of cilia in...

Maiti, S.; Pandey, S. K.

2013-01-01

397

Rheology of Nanoparticle Suspensions in Hydroxypropylcellulose (HPC) Solutions  

Science.gov (United States)

The effect of nanoparticle shape and concentration on the rheology of liquid crystalline solutions of hydroxypropyl cellulose (HPC) has been studied experimentally. Multiwalled carbon nanotubes (MWCNT) were dispersed by ultrasonification in HPC/M-cresol solutions, while commercial aqueous colloidal silica suspensions were mixed with HPC in water. The liquid crystalline phase behavior was identified by rheological measurements of the viscosity and optical microscopy of the solutions. Scaling arguments for the steady-state viscosity and the dynamic viscoelastic moduli will be presented. The effects of dispersion methods are also addressed.

Avilés-Barreto, Sonia L.; Acevedo-Rullán, Aldo

2008-07-01

398

REAL WASTE TESTING OF SLUDGE BATCH 5 MELTER FEED RHEOLOGY  

Energy Technology Data Exchange (ETDEWEB)

Clogging of the melter feed loop at the Defense Waste Processing Facility (DWPF) has reduced the throughput of Sludge Batch 5 (SB5) processing. After completing a data review, DWPF attributed the clogging to the rheological properties of the Slurry Mix Evaporator (SME) project. The yield stress of the SB5 melter feed material was expected to be high, based on the relatively high pH of the SME product and the rheological results of a previous Chemical Process Cell (CPC) demonstration performed at the Savannah River National Laboratory (SRNL).

Reboul, S.; Stone, M.

2010-03-17

399

Rheological properties of Pb, Sb, Bi, and Sn melts  

Science.gov (United States)

The rheological properties of metal Pb, Sb, Bi, and Sn melts were investigated using a coaxial cylinder high-temperature viscometer. The results show that the torque value decreases with increasing temperature, which is consistent with the temperature dependence of their viscosity. The relationship between the torque and rotational rate of the Sb and Pb melt exhibits a linear change in the measured temperature range, but that of the Bi and Sn melts shows an obvious non-Newtonian characteristic in the low-temperature range and at relatively high shear stress. The rheological characteristics of the melts were correlated with the evolution of microstructure. The discussion was made in detail.

Sun, Chunjing; Geng, Haoran; Ji, Leilei; Wang, Yan; Wang, Guizhen

2007-08-01

400

Development of a rheological analogue to periprosthetic fluid.  

Science.gov (United States)

The purpose of this work is to design a rheological analogue to periprosthetic fluid, for potential use in wear testing of orthopaedic implants. Polymer solutions of sodium carboxymethyl cellulose (CMC), xanthan and mixtures thereof were prepared, and the experimentally determined viscosity-shear rate dependence was analyzed using the three-parameter modified Cross model. A mixture containing 0.185 wt% CMC and 0.075 wt% xanthan was identified as being the closest rheological match for periprosthetic fluid in both steady shear and oscillatory modes of deformation. PMID:16227657

Fam, H; Kontopoulou, M; Bryant, J T

2005-01-01

 
 
 
 
401

Analysis of Rheological Models of Selected Cement Slurries  

Directory of Open Access Journals (Sweden)

Full Text Available Cement slurries become more and more widely applicable in reinforcing and strengthening the rock mass. The processes taking place in fresh cement slurries were presented and their complex character analysed. The equations describing rheological models, e.g. cement slurries, were given. The selected cement slurries were analysed in laboratory conditions for various water-cement parameters and three temperatures. The obtained results were statistically analysed and the best fit of the rheological model to the individual cement slurries was shown.

Stryczek Stanislaw

2004-03-01

402

Rheological investigation of agricultural and food-industrial products  

International Nuclear Information System (INIS)

We investigated the rheological properties of protein-containing food-industrial ingredient (milk protein concentrate powder and whole egg powder) as a function of absorbed gamma-dose (max. 20 kGy), using rotational viscosimeters. Our investigations form part of complex examination for comparing the above results with those of thermoluminescence, chemiluminescence and electron spin resonance methods applied for the study of irradiated foodstuffs. It was found that the rheological method was suitable for significant detection of irradiation in the case of protein-containing foodstuffs, even after a longer storage. (author). 8 refs, 5 figs, 1 tab

1994-01-01

403

Stabilizers: indispensable substances in dairy products of high rheology.  

Science.gov (United States)

The functionality of stabilizers is apparent in many food applications including dairy products. The role of stabilizers like gelatin, pectins, alginates, carboxymethylcellulose, gums, ispghol, sago starch, and chitosan in the development of dairy products of high rheology, like yoghurt, ice cream, and flavored milk, is discussed in this review. Attention is also paid to comprehend on interactions among milk proteins, minerals, and other milk constituents with the reactive sites of stabilizers to get the desirable properties such as appearance, body and texture, mouthfeel, consistency. The role played by stabilizers in the control of syneresis and overrun problems in the high-rheology dairy products is also the topic of discussion. PMID:24499066

Tasneem, Madiha; Siddique, Farzana; Ahmad, Asif; Farooq, Umar

2014-01-01

404

Investigations of lubricant rheology as applied to elastohydrodynamic lubrication  

Science.gov (United States)

Measurements of lubricant shear rheological behavior in the amorphous solid region and near the liquid-solid transition are reported. Elastic, plastic and viscous behavior was observed. A shear rheological model based on primary laboratory data is proposed for concentrated contact lubrication. The model is a Maxwell model modified with a limiting shear stress. Three material properties are required: low shear stress viscosity, limiting elastic shear modulus, and the limiting shear stress the material can withstand. All three are functions of temperature and pressure. In applying the model to EHD contacts the predicted response possesses the characteristics expected from several experiments reported in the literature.

Bair, S.; Winer, W. O.

1978-01-01

405

Field-responsive smart composite particle suspension: materials and rheology  

Science.gov (United States)

Both electrorheological (ER) and magnetorheological (MR) fluids are known to be smart materials which can be rapidly and reversibly transformed from a fluid-like to a solid-like state within milliseconds by showing dramatic and tunable changes in their rheological properties under external electrical or magnetic field strength, respectively. Here, among various smart composite particles studied, recently developed core-shell structured polystyrene/graphene oxide composite based ER material as well as the dual-step functionally coated carbonyl iron composite based MR material are briefly reviewed along with their rheological characteristics under external fields.

Zhang, Wen Ling; Liu, Ying Dan; Choi, Hyoung Jin

2012-09-01

406

Hybrid inorganic-organic polymer electrolytes: synthesis, FT-Raman studies and conductivity of {l_brace}Zr[(CH{sub 2}CH{sub 2}O){sub 8.7}]{sub {rho}}/(LiClO{sub 4}){sub z}{r_brace}{sub n} network complexes  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the synthesis and characterization of three-dimensional hybrid inorganic-organic networks prepared by a polycondensation reaction between Zr(O(CH{sub 2}){sub 3}CH{sub 3}){sub 4} and polyethylene glycol 400 (PEG400). Eleven hybrid networks doped with varying concentrations of LiClO{sub 4} 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 T{sub g} of these inorganic-organic hybrids varies from -43 to -15 deg. C with increasing LiClO{sub 4} 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 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 n{sub Li}/n{sub O} molar ratio of 0.0223 shows a conductivity of ca. 1x10{sup -5} S cm{sup -1} at 40 deg. C.

Di Noto, Vito; Zago, Vanni; Biscazzo, Simone; Vittadello, Michele

2003-01-15

407

Electrolytic hydrogen fuel production with solid polymer electrolyte technology.  

Science.gov (United States)

A water electrolysis technology based on a solid polymer electrolyte (SPE) concept is presented for applicability to large-scale hydrogen production in a future energy system. High cell current density operation is selected for the application, and supporting cell test performance data are presented. Demonstrated cell life data are included to support the adaptability of the SPE system to large-size hydrogen generation utility plants as needed for bulk energy storage or transmission. The inherent system advantages of the acid SPE electrolysis technology are explained. System performance predictions are made through the year 2000, along with plant capital and operating cost projections.

Titterington, W. A.; Fickett, A. P.

1973-01-01