Mixing, diffusion, and percolation in binary supported membranes containing mixtures of lipids and amphiphilic block copolymers.

PubMed

Gettel, Douglas L; Sanborn, Jeremy; Patel, Mira A; de Hoog, Hans-Peter; Liedberg, Bo; Nallani, Madhavan; Parikh, Atul N

2014-07-23

Substrate-mediated fusion of small polymersomes, derived from mixtures of lipids and amphiphilic block copolymers, produces hybrid, supported planar bilayers at hydrophilic surfaces, monolayers at hydrophobic surfaces, and binary monolayer/bilayer patterns at amphiphilic surfaces, directly responding to local measures of (and variations in) surface free energy. Despite the large thickness mismatch in their hydrophobic cores, the hybrid membranes do not exhibit microscopic phase separation, reflecting irreversible adsorption and limited lateral reorganization of the polymer component. With increasing fluid-phase lipid fraction, these hybrid, supported membranes undergo a fluidity transition, producing a fully percolating fluid lipid phase beyond a critical area fraction, which matches the percolation threshold for the immobile point obstacles. This then suggests that polymer-lipid hybrid membranes might be useful models for studying obstructed diffusion, such as occurs in lipid membranes containing proteins.

Co-elution phenomena in polymer mixtures studied by asymmetric flow field-flow fractionation.

PubMed

Zielke, Claudia; Fuentes, Catalina; Piculell, Lennart; Nilsson, Lars

2018-01-12

Most polymers generally have complex characteristics. Analysis and understanding of these characteristics is crucial as they, for instance, influence functionality. Separation and analysis of samples of polymers, biopolymers in particular, is challenging since they often display broad distributions in size, structure and molar mass (M) and/or a tendency to form aggregates. Only few analytical techniques are suitable for the task. AF4-MALS-dRI is highly suited for the task, but the analysis can nevertheless be especially challenging for heterogeneous mixtures of polymers that exhibit wide size distributions or aggregation. For such systems, systematic and thorough method development is clearly a requirement. This is the purpose of the present work, where we approach the problem of heterogeneous polymer samples systematically by analyzing mixtures of two different polymers which are also characterized individually. An often observed phenomenon in AF4 of samples with a high polydispersity is a downturn in M vs. elution time, especially common at high retention. This result is often dismissed as an artifact attributed to various errors in detection and data processing. In this work, we utilize AF4-MALS-dRI to separate and analyze binary mixtures of the well-known polysaccharides pullulan and glycogen, or pullulan and poly(ethylene oxide), respectively, in solution. The results show that an observed downturn - or even an upturn - in M can be a correct result, caused by inherent properties of the analyzed polymers. Copyright © 2017 Elsevier B.V. All rights reserved.

Elasticity dominated surface segregation of small molecules in polymer mixtures

NASA Astrophysics Data System (ADS)

Croce, Salvatore; Krawczyk, Jaroslaw; McLeish, Tom; Chakrabarti, Buddhapriya

When a binary polymer mixture with mobile components is left to equilibrate, the low molecular weight component migrates to the free surface. A balance between loss of translational entropy and gain in surface energy dictates the equilibrium partitioning ratio and the migrant fraction. Despite its ubiquity and several theoretical and experimental investigations, the phenomenon is not fully understood. Further, methods by which migration can be controlled are in its nascent stage of development. We propose a new phenomenological free energy functional that incorporates the elasticity of bulk polymer mixtures (reticulated networks and gels) and show (using mean field and self-consistent field theories) that the migrant fraction decreases with increasing the bulk modulus of the system. Further, a wetting transition observed otherwise for large values of miscibility parameter and polymerization index can be avoided by increasing the elastic modulus of the system. Estimated values of moduli (for the effect to be observable) are akin to those of rubbery polymers. Our work paves the way for controlling surface migration in complex industrial formulations with polymeric ingredients where this effect leads to decreased product stability and performance.

Multicomponent Diffusion of Penetrant Mixtures in Rubbery Polymers: A Molecular Dynamics Study

NASA Astrophysics Data System (ADS)

Bringuier, Stefan; Varady, Mark; Knox, Craig; Cabalo, Jerry; Pearl, Thomas; Mantooth, Brent

The importance of understanding transport of chemical species across liquid-solid boundaries is of particular interest in the decontamination of harmful chemicals absorbed within polymeric materials. To characterize processes associated with liquid-phase extraction of absorbed species from polymers, it is necessary to determine an appropriate physical description of species transport in multicomponent systems. The Maxwell-Stefan (M-S) formulation is a rigorous description of mass transport in multicomponent solutions, in which, mutual diffusivities determine the degree of relative motion between interacting molecules in response to a chemical potential gradient. The work presented focuses on the determination of M-S diffusivities from molecular dynamics (MD) simulations of nerve agent O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothioate (VX), water, and methanol mixtures within a poly(dimethylsiloxane) matrix. We investigate the composition dependence of M-S diffusivities and compare the results to values predicted using empirical relations for binary and ternary mixtures. Finally, we highlight the pertinent differences in molecular mechanisms associated with species transport and employ non-equilibrium MD to probe transport across the mixture-polymer interface.

Application of a constant hole volume Sanchez-Lacombe equation of state to mixtures relevant to polymeric foaming.

PubMed

von Konigslow, Kier; Park, Chul B; Thompson, Russell B

2018-06-06

A variant of the Sanchez-Lacombe equation of state is applied to several polymers, blowing agents, and saturated mixtures of interest to the polymer foaming industry. These are low-density polyethylene-carbon dioxide and polylactide-carbon dioxide saturated mixtures as well as polystyrene-carbon dioxide-dimethyl ether and polystyrene-carbon dioxide-nitrogen ternary saturated mixtures. Good agreement is achieved between theoretically predicted and experimentally determined solubilities, both for binary and ternary mixtures. Acceptable agreement with swelling ratios is found with no free parameters. Up-to-date pure component Sanchez-Lacombe characteristic parameters are provided for carbon dioxide, dimethyl ether, low-density polyethylene, nitrogen, polylactide, linear and branched polypropylene, and polystyrene. Pure fluid low-density polyethylene and nitrogen parameters exhibit more moderate success while still providing acceptable quantitative estimations. Mixture estimations are found to have more moderate success where pure components are not as well represented. The Sanchez-Lacombe equation of state is found to correctly predict the anomalous reversal of solubility temperature dependence for low critical point fluids through the observation of this behaviour in polystyrene nitrogen mixtures.

Improved oral bioavailability of probucol by dry media-milling.

PubMed

Li, Jia; Yang, Yan; Zhao, Meihui; Xu, Hui; Ma, Junyuan; Wang, Shaoning

2017-09-01

The polymer/probucol co-milled mixtures were prepared to improve drug dissolution rate and oral bioavailability. Probucol, a BCS II drug, was co-milled together with Copovidone (Kollidon VA64, VA64), Soluplus, or MCC using the dry media-milling process with planetary ball-milling equipment. The properties of the milled mixtures including morphology, crystal form, vitro drug dissolution and in vivo oral bioavailability in rats were evaluated. Probucol existed as an amorphous in the matrix of the co-milled mixtures containing VA64, which helped to enhance drug dissolution. The ternary mixture composed of VA64, RH40, and probucol showed increased dissolution rates in both sink and non-sink conditions. It also had a higher oral bioavailability compared to the reference formulation. Dry-media milling of binary or ternary mixtures composed of drug, polymer and surfactant possibly have wide applications to improve dissolution rate and oral bioavailability of water-insoluble drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Dual release and molecular mechanism of bilayered aceclofenac tablet using polymer mixture.

PubMed

Van Nguyen, Hien; Nguyen, Van Hong; Lee, Beom-Jin

2016-12-30

The objectives of the present study were to develop a controlled-release bilayered tablet of aceclofenac (AFN) 200mg with dual release and to gain a mechanistic understanding of the enhanced sustained release capability achieved by utilizing a binary mixture of the sustained release materials. Different formulations of the sustained-release layer were formulated by employing hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC) as the major retarding polymers. The in vitro dissolution studies of AFN bilayered tablets were carried out in intestinal fluid (pH 6.8 buffer). The mechanism of the synergistic rate-retarding effect of the polymer mixture containing HPC and carbomer was elucidated by the rate of swelling and erosion in intestinal fluid and the molecular interactions in the polymer network. The optimized bilayered tablets had similar in vitro dissolution profiles to the marketed tablet Clanza ® CR based on the similarity factor (f2) in combination with their satisfactory micromeritic, physicochemical properties, and stability profiles. Drug release from HPMC-based matrix was controlled by non-Fickian transport, while drug release from HPC-based matrix was solely governed by drug diffusion. The swelling and erosion data exhibited a dramatic increase of water uptake and a reduction of weight loss in the polymer mixture-loaded tablet. Fourier transform infrared (FTIR) spectra revealed strong hydrogen bonding between HPC and carbomer in the polymer mixture. Regarding spatial distribution of polymers in the polymer mixture-loaded tablet, carbomer was found to be the main component of the gel layer during the first 2h of the hydration process, which was responsible for retarding drug release at initial stage. This process was then followed by a gradual transition of HPC from the glassy core to the gel layer for further increasing gel strength. Copyright © 2016 Elsevier B.V. All rights reserved.

COAL/POLYMER COPROCESSING WITH EFFICIENT USE OF HYDROGEN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dr. Linda J. Broadbelt; Matthew J. DeWitt; Hsi-Wu Wong

2000-09-30

The final project period was devoted to investigating the binary mixture pyrolysis of polypropylene and polystyrene. Their interactions were assessed in order to provide a baseline for experiments with multicomponent mixtures of polymers with coal. Pyrolysis of polypropylene, polystyrene and their binary mixture was investigated at temperatures of 350 C and 420 C with reaction times from 1 to 180 minutes. Two different loadings, 10 mg and 20 mg, were studied for neat polypropylene and polystyrene to assess the effect of total pressure on product yields and selectivities. For neat pyrolysis of polypropylene, total conversion was much higher at 420more » C, and no significant effect of loading on the total conversion was observed. Four classes of products, alkanes, alkenes, dienes, and aromatic compounds, were observed, and their distribution was explained by a typical free radical mechanism. For neat polystyrene pyrolysis, conversion reached approximately 75% at 350 C, while at 420 C the conversion reached a maximum around 90% at 10 minutes and decreased at longer times because of condensation reactions. The selectivities to major products were slightly different for the two different loadings due to the effect of total reaction pressure on secondary reactions. For binary mixture pyrolysis, the overall conversion was higher than the average of the two neat cases. The conversion of polystyrene remained the same, but a significant enhancement in the polypropylene conversion was observed. This suggests that the less reactive polypropylene was initiated by polystyrene-derived radicals. These results are summarized in detail in an attached manuscript that is currently in preparation. The other results obtained during the lifetime of this grant are documented in the set of attached manuscripts.« less

Thermodynamics and Phase Behavior of Miscible Polymer Blends in the Presence of Supercritical Carbon Dioxide

NASA Astrophysics Data System (ADS)

Young, Nicholas Philip

The design of environmentally-benign polymer processing techniques is an area of growing interest, motivated by the desire to reduce the emission of volatile organic compounds. Recently, supercritical carbon dioxide (scCO 2) has gained traction as a viable candidate to process polymers both as a solvent and diluent. The focus of this work was to elucidate the nature of the interactions between scCO2 and polymers in order to provide rational insight into the molecular interactions which result in the unexpected mixing thermodynamics in one such system. The work also provides insight into the nature of pairwise thermodynamic interactions in multicomponent polymer-polymer-diluent blends, and the effect of these interactions on the phase behavior of the mixture. In order to quantify the strength of interactions in the multicomponent system, the binary mixtures were characterized individually in addition to the ternary blend. Quantitative analysis of was made tractable through the use of a model miscible polymer blend containing styrene-acrylonitrile copolymer (SAN) and poly(methyl methacrylate) (dPMMA), a mixture which has been considered for a variety of practical applications. In the case of both individual polymers, scCO2 is known to behave as a diluent, wherein the extent of polymer swelling depends on both temperature and pressure. The solubility of scCO 2 in each polymer as a function of temperature and pressure was characterized elsewhere. The SAN-dPMMA blend clearly exhibited lower critical solution temperature behavior, forming homogeneous mixtures at low temperatures and phase separating at elevated temperature. These measurements allowed the determination of the Flory-Huggins interaction parameter chi23 for SAN (species 2) and dPMMA (species 3) as a function of temperature at ambient pressure, in the absence of scCO2 (species 1). Characterization of the phase behavior of the multicomponent (ternary) mixture was also carried out by SANS. An in situ SANS environment was developed to allow measurement of blend miscibility in the presence of scCO2. The pressure-temperature phase behavior of the system could be mapped by approaching the point of phase separation by spinodal decomposition through pressure increases at constant temperature. For a roughly symmetric mixture of SAN and dPMMA, the temperature at which phase separation occurred could be decreased by over 125 °C. The extent to which the phase behavior of the multicomponent system could be tuned motivated further investigation into the interactions present within the homogeneous mixtures. Analysis of the SANS results for homogeneous mixtures was undertaken using a new multicomponent formalism of the random phase approximation theory. The scattering profiles obtained from the scCO2-SAN-dPMMA system could be predicted with reasonable success. The success of the theoretical predictions was facilitated by directly employing the interactions found in the binary experiments. Exploitation of the condition of homogeneity with respect to chemical potential allowed determination of interaction parameters for scCO2-SAN and 2-dPMMA within the multicomponent mixture (chi12 and chi13, respectively). Studying this system over a large range of the supercritical regime yielded insight on the nature of interactions in the system. Near the critical point of scCO 2, chi12 and chi13 increase monotonically as a function of pressure. Conversely, at elevated temperature away from the critical point, the interaction parameters are found to go through a minimum as a pressure increases. Analysis of the critical phenomenon associated with scCO2 suggests that the observed dependence of chi12 and chi13 on pressure are related to the magnitude of scCO 2 density fluctuations and the proximity of the system to the so-called density fluctuation ridge. By tuning the system parameters of the multicomponent mixture, the phase behavior can be altered through the balance of pairwise interactions been the constituent species. The presence of scCO2 in the mixtures appears to eliminate the existence of the metastable state that epitomizes most polymer-polymer mixtures. Thus it is shown that knowledge of the individual pairwise interactions in such multicomponent mixtures can greatly influence the resulting phase behavior, and provide insight into the design of improved functional materials with decreased environmental impacts.

Formulation of 3D Printed Tablet for Rapid Drug Release by Fused Deposition Modeling: Screening Polymers for Drug Release, Drug-Polymer Miscibility and Printability.

PubMed

Solanki, Nayan G; Tahsin, Md; Shah, Ankita V; Serajuddin, Abu T M

2018-01-01

The primary aim of this study was to identify pharmaceutically acceptable amorphous polymers for producing 3D printed tablets of a model drug, haloperidol, for rapid release by fused deposition modeling. Filaments for 3D printing were prepared by hot melt extrusion at 150°C with 10% and 20% w/w of haloperidol using Kollidon ® VA64, Kollicoat ® IR, Affinsiol ™ 15 cP, and HPMCAS either individually or as binary blends (Kollidon ® VA64 + Affinisol ™ 15 cP, 1:1; Kollidon ® VA64 + HPMCAS, 1:1). Dissolution of crushed extrudates was studied at pH 2 and 6.8, and formulations demonstrating rapid dissolution rates were then analyzed for drug-polymer, polymer-polymer and drug-polymer-polymer miscibility by film casting. Polymer-polymer (1:1) and drug-polymer-polymer (1:5:5 and 2:5:5) mixtures were found to be miscible. Tablets with 100% and 60% infill were printed using MakerBot printer at 210°C, and dissolution tests of tablets were conducted at pH 2 and 6.8. Extruded filaments of Kollidon ® VA64-Affinisol ™ 15 cP mixtures were flexible and had optimum mechanical strength for 3D printing. Tablets containing 10% drug with 60% and 100% infill showed complete drug release at pH 2 in 45 and 120 min, respectively. Relatively high dissolution rates were also observed at pH 6.8. The 1:1-mixture of Kollidon ® VA64 and Affinisol ™ 15 cP was thus identified as a suitable polymer system for 3D printing and rapid drug release. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Crosslinked Polymer Ionic Liquid/Ionic Liquid Blends Prepared by Photopolymerization as Solid-State Electrolytes in Supercapacitors.

PubMed

Wang, Po-Hsin; Wang, Tzong-Liu; Lin, Wen-Churng; Lin, Hung-Yin; Lee, Mei-Hwa; Yang, Chien-Hsin

2018-04-07

A photopolymerization method is used to prepare a mixture of polymer ionic liquid (PIL) and ionic liquid (IL). This mixture is used as a solid-state electrolyte in carbon nanoparticle (CNP)-based symmetric supercapacitors. The solid electrolyte is a binary mixture of a PIL and its corresponding IL. The PIL matrix is a cross-linked polyelectrolyte with an imidazole salt cation coupled with two anions of Br - in PIL-M-(Br) and TFSI - in PIL-M-(TFSI), respectively. The corresponding ionic liquids have imidazolium salt cation coupled with two anions of Br - and TFSI - , respectively. This study investigates the electrochemical characteristics of PILs and their corresponding IL mixtures used as a solid electrolyte in supercapacitors. Results show that a specific capacitance, maximum power density and energy density of 87 and 58 F·g - ¹, 40 and 48 kW·kg - ¹, and 107 and 59.9 Wh·kg - ¹ were achieved in supercapacitors based on (PIL-M-(Br)) and (PIL-M-(TFSI)) solid electrolytes, respectively.

Communication: Cosolvency and cononsolvency explained in terms of a Flory-Huggins type theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudowicz, Jacek, E-mail: dudowicz@jfi.uchicago.edu; Freed, Karl F.; Douglas, Jack F.

2015-10-07

Standard Flory-Huggins (FH) theory is utilized to describe the enigmatic cosolvency and cononsolvency phenomena for systems of polymers dissolved in mixed solvents. In particular, phase boundaries (specifically upper critical solution temperature spinodals) are calculated for solutions of homopolymers B in pure solvents and in binary mixtures of small molecule liquids A and C. The miscibility (or immiscibility) patterns for the ternary systems are classified in terms of the FH binary interaction parameters (χ{sub αβ}) and the ratio r = ϕ{sub A}/ϕ{sub C} of the concentrations ϕ{sub A} and ϕ{sub C} of the two solvents. The trends in miscibility are comparedmore » to those observed for blends of random copolymers (A{sub x}C{sub 1−x}) with homopolymers (B) and to those deduced for A/B/C solutions of polymers B in liquid mixtures of small molecules A and C that associate into polymeric clusters (A{sub p}C{sub q}){sub i}, (i = 1, 2, …, ∞). Although the classic FH theory is able to explain cosolvency and cononsolvency phenomena, the theory does not include a consideration of the mutual association of the solvent molecules and the competitive association between the solvent molecules and the polymer. These interactions can be incorporated in refinements of the FH theory, and the present paper provides a foundation for such extensions for modeling the rich thermodynamics of polymers in mixed solvents.« less

A computational investigation of the thermodynamics and structure in colloid and polymer mixtures

NASA Astrophysics Data System (ADS)

Mahynski, Nathan Alexander

In this dissertation I use computational tools to study the structure and thermodynamics of colloid-polymer mixtures. I show that fluid-fluid phase separation in mixtures of colloids and linear polymers cannot be universally reduced using polymer-based scaling principles since these assume the binodals exist in a single scaling regime, whereas accurate simulations clearly demonstrate otherwise. I show that rethinking these solutions in terms of multiple length scales is necessary to properly explain the thermodynamic stability and structure of these fluid phases, and produce phase diagrams in nearly quantitative agreement with experimental results. I then extend this work to encompass more geometrically complex "star" polymers revealing how the phase behavior for many of these binary mixtures may be mapped onto that of mixtures containing only linear polymers. I further consider the depletion-driven crystallization of athermal colloidal hard spheres induced by polymers. I demonstrate how the partitioning of a finite amount of polymer into the colloidal crystal phase implies that the polymer's architecture can be tailored to interact with the internal void structure of different crystal polymorphs uniquely, thus providing a direct route to thermodynamically stabilizing one arbitrarily chosen structure over another, e.g., the hexagonal close-packed crystal over the face-centered cubic. I then begin to generalize this result by considering the consequences of thermal interactions and complex polymer architectures. These principles lay the groundwork for intelligently engineering co-solute additives in crystallizing colloidal suspensions that can be used to thermodynamically isolate single crystal morphologies. Finally, I examine the competition between self-assembly and phase separation in polymer-grafted nanoparticle systems by comparing and contrasting the validity of two different models for grafted nanoparticles: "nanoparticle amphiphiles" versus "patchy particles." The latter suggests these systems have some utility in forming novel "equilibrium gel" phases, however, I find that considering grafted nanoparticles as amphiphiles provides a qualitatively accurate description of their thermodynamics revealing either first-order phase separation into two isotropic phases or continuous self-assembly. I find no signs of empty liquid formation, suggesting that these nanoparticles do not provide a route to such phases.

Thermal transport in binary colloidal glasses: Composition dependence and percolation assessment

NASA Astrophysics Data System (ADS)

Ruckdeschel, Pia; Philipp, Alexandra; Kopera, Bernd A. F.; Bitterlich, Flora; Dulle, Martin; Pech-May, Nelson W.; Retsch, Markus

2018-02-01

The combination of various types of materials is often used to create superior composites that outperform the pure phase components. For any rational design, the thermal conductivity of the composite as a function of the volume fraction of the filler component needs to be known. When approaching the nanoscale, the homogeneous mixture of various components poses an additional challenge. Here, we investigate binary nanocomposite materials based on polymer latex beads and hollow silica nanoparticles. These form randomly mixed colloidal glasses on a sub-μ m scale. We focus on the heat transport properties through such binary assembly structures. The thermal conductivity can be well described by the effective medium theory. However, film formation of the soft polymer component leads to phase segregation and a mismatch between existing mixing models. We confirm our experimental data by finite element modeling. This additionally allowed us to assess the onset of thermal transport percolation in such random particulate structures. Our study contributes to a better understanding of thermal transport through heterostructured particulate assemblies.

Dissolution stability studies of suspensions of prolonged-release diclofenac microcapsules prepared by the Wurster process: I. Eudragit-based formulation and possible drug-excipient interaction.

PubMed

Adeyeye, M C; Mwangi, E; Katondo, B; Jain, A; Ichikawa, H; Fukumori, Y

2005-06-01

The aim was to evaluate possible interaction in solid and liquid state of the drug with formulation excipients consequent to very fast drug release of diclofenac-Eudragit prolonged release microcapsules. The microcapsules were prepared by drug layering on calcium carbonate cores and coated with Eudragit RS 30D and L30D-55 as previously reported. Suspension of the microcapsules was prepared using microcrystalline cellulose/sodium carboxymethyl cellulose (Avicel CL-611) as medium. In vitro dissolution testing of the suspension was done, and, based on the dissolution results, possible interaction between diclofenac and Eudragit and Avicel in the medium was studied. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) analyses were performed using 1:1 binary, 1:1:1 ternary mixtures and a ratio equivalent to that in the formulation. The mixtures were prepared by mixing the dispersions--Eudragit RS 30D or L30D-55 with the drug or other components, followed by drying at 60 degrees C for 48 h. Dry mixing was done using the powder equivalents of the polymers, Eudragit RS PO and L100-55, Avicel and calcium carbonate. In vitro dissolution of the suspended microcapsules showed a very fast release after 48 h (T50 = <1 h) compared to the solid microcapsules (T50 = 6 h). DSC curves of the formulation components or microcapsules did not show the characteristic endothermic peak of diclofenac at 287 degrees C. Powder X-ray diffraction of the binary or ternary mixtures of diclofenac and Eudragit polymers indicated reduction, shift or modification of the crystalline peaks of the drug or excipients at 2theta of 12 degrees and 18 degrees , suggestive of interaction. Some changes in drug peak characteristics at 18 degrees and 23 degrees were observed for Avicel/drug mixture, though not significant. The DSC curves of the binary mixture of diclofenac co-dried with liquid forms of Eudragit (i.e. RS 30D or L30D-55) revealed greater interaction compared to the curves of drug and powdered forms of Eudragit (RS PO or L100-55). This was depicted by greater shift in fusion points of the mixtures relative to the drug. However, comparing the RS and L-type Eudragit, the latter generally showed greater interaction with the drug. Interaction between diclofenac and L-type Eudragit polymers can occur in liquid formulations.

Molecular dynamics simulation of a needle-sphere binary mixture

NASA Astrophysics Data System (ADS)

Raghavan, Karthik

This paper investigates the dynamic behaviour of a hard needle-sphere binary system using a novel numerical technique called the Newton homotopy continuation (NHC) method. This mixture is representative of a polymer melt where both long chain molecules and monomers coexist. Since the intermolecular forces are generated from hard body interactions, the consequence of missed collisions or incorrect collision sequences have a significant bearing on the dynamic properties of the fluid. To overcome this problem, in earlier work NHC was chosen over traditional Newton-Raphson methods to solve the hard body dynamics of a needle fluid in random media composed of overlapping spheres. Furthermore, the simplicity of interactions and dynamics allows us to focus our research directly on the effects of particle shape and density on the transport behaviour of the mixture. These studies are also compared with earlier works that examined molecular chains in porous media primarily to understand the differences in molecular transport in the bulk versus porous systems.

Monolithic composites of silica aerogels by reactive supercritical deposition of hydroxy-terminated poly(dimethylsiloxane).

PubMed

Sanli, D; Erkey, C

2013-11-27

Monolithic composites of silica aerogels with hydroxyl-terminated poly(dimethylsiloxane) (PDMS(OH)) were developed with a novel reactive supercritical deposition technique. The method involves dissolution of PDMS(OH) in supercritical CO2 (scCO2) and then exposure of the aerogel samples to this single phase mixture of PDMS(OH)-CO2. The demixing pressures of the PDMS(OH)-CO2 binary mixtures determined in this study indicated that PDMS(OH) forms miscible mixtures with CO2 at a wide composition range at easily accessible pressures. Upon supercritical deposition, the polymer molecules were discovered to react with the hydroxyl groups on the silica aerogel surface and form a conformal coating on the surface. The chemical attachment of the polymer molecules on the aerogel surface were verified by prolonged extraction with pure scCO2, simultaneous deposition with superhydrophobic and hydrophilic silica aerogel samples and ATR-FTIR analysis. All of the deposited silica aerogel samples were obtained as monoliths and retained their transparency up to around 30 wt % of mass uptake. PDMS(OH) molecules were found to penetrate all the way to the center of the monoliths and were distributed homogenously throughout the cylindrical aerogel samples. Polymer loadings as high as 75.4 wt % of the aerogel mass could be attained. It was shown that the polymer uptake increases with increasing exposure time, as well as the initial polymer concentration in the vessel.

Crosslinked Polymer Ionic Liquid/Ionic Liquid Blends Prepared by Photopolymerization as Solid-State Electrolytes in Supercapacitors

PubMed Central

Wang, Po-Hsin; Wang, Tzong-Liu; Lin, Wen-Churng; Lin, Hung-Yin; Lee, Mei-Hwa; Yang, Chien-Hsin

2018-01-01

A photopolymerization method is used to prepare a mixture of polymer ionic liquid (PIL) and ionic liquid (IL). This mixture is used as a solid-state electrolyte in carbon nanoparticle (CNP)-based symmetric supercapacitors. The solid electrolyte is a binary mixture of a PIL and its corresponding IL. The PIL matrix is a cross-linked polyelectrolyte with an imidazole salt cation coupled with two anions of Br− in PIL-M-(Br) and TFSI− in PIL-M-(TFSI), respectively. The corresponding ionic liquids have imidazolium salt cation coupled with two anions of Br− and TFSI−, respectively. This study investigates the electrochemical characteristics of PILs and their corresponding IL mixtures used as a solid electrolyte in supercapacitors. Results show that a specific capacitance, maximum power density and energy density of 87 and 58 F·g−1, 40 and 48 kW·kg−1, and 107 and 59.9 Wh·kg−1 were achieved in supercapacitors based on (PIL-M-(Br)) and (PIL-M-(TFSI)) solid electrolytes, respectively. PMID:29642456

A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose.

PubMed

Sun, Xiuhua; Yang, Weichun; Geng, Yanli; Woolley, Adam T

2009-04-07

We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose (HPC) in a spin-coated thin film on the surface. Poly(methyl methacrylate-8.5-methacrylic acid), a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces. Various amounts of HPC (0.1-2.0%) dissolved in the copolymer and spun on polymer surfaces were evaluated. The modified surfaces were characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. The developed method was applied on both poly(methyl methacrylate) and cyclic olefin copolymer microchips. A fluorescently labeled myoglobin digest, binary protein mixture, and human serum sample were all separated in these surface-modified polymer microdevices. Our work exhibits an easy and reliable way to achieve favorable biomolecular separation performance in polymer microchips.

A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose

PubMed Central

Sun, Xiuhua; Yang, Weichun; Geng, Yanli; Woolley, Adam T.

2009-01-01

We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose (HPC) in a spin-coated thin film on the surface. Poly(methyl methacrylate-8.5-methacrylic acid), a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces. Various amounts of HPC (0.1–2.0%) dissolved in the copolymer and spun on polymer surfaces were evaluated. The modified surfaces were characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. The developed method was applied on both poly(methyl methacrylate) and cyclic olefin copolymer microchips. A fluorescently labeled myoglobin digest, binary protein mixture, and human serum sample were all separated in these surface-modified polymer microdevices. Our work exhibits an easy and reliable way to achieve favorable biomolecular separation performance in polymer microchips. PMID:19294306

Dynamical studies of confined fluids and polymers

NASA Astrophysics Data System (ADS)

Grabowski, Christopher A.

Soft matter, a class of materials including polymers, colloids, and surfactant molecules, are ubiquitous in our everyday lives. Plastics, soaps, foods and living organisms are mostly comprised of soft materials. Research conducted to understand soft matter behavior at the molecular level is essential to create new materials with unique properties. Self-healing plastics, targeted drug delivery, and nanowire assemblies have all been further advanced by soft matter research. The author of this dissertation investigates fundamental soft matter systems, including polymer solutions and melts, colloid dispersions in polymer melts, and interfacial fluids. The dynamics of polymers and confined fluids were studied using the single-molecule sensitive technique of fluorescence correlation spectroscopy (FCS). Here, fluorescent dyes are attached to polymer coils or by introducing free dyes directly into the solution/film. Complementary experiments were also performed, utilizing atomic force microscopy (AFM) and ellipsometry. FCS and AFM experiments demonstrated the significant difference in properties of thin fluid films of the nearly spherical, nonpolar molecule TEHOS (tetrakis(2-ethylhexoxy)silane) when compared to its bulk counterpart. AFM experiments confirmed TEHOS orders in layers near a solid substrate. FCS experiments show that free dyes introduced in these thin films do not have a single diffusion coefficient, indicating that these films have heterogeneity at the molecular level. FCS experiments have been applied to study the diffusion of gold colloids. The diffusion of gold colloids in polymer melts was found to dramatically depart from the Stokes-Einstein prediction when colloid size was smaller than the surrounding polymer mesh size. This effect is explained by noting the viscosity experienced by the colloid is not equivalent to the overall bulk viscosity of the polymer melt. The conformational change of polymers immersed in a binary solvent was measured via FCS. This experiment was conducted to test a theory proposed by Brochard and de Gennes, who postulated a polymer chain undergoes a collapse and a dramatic re-swelling as the critical point of the binary mixture is approached. Measuring polymer chain diffusion as a function of temperature, this theory was confirmed. To my knowledge, this was the first experimental evidence of contraction/re-swelling for polymers in critical binary solvents.

Evidence for the interactions occurring between ionic liquids and tetraethylene glycol in binary mixtures and aqueous biphasic systems.

PubMed

Tomé, Luciana I N; Pereira, Jorge F B; Rogers, Robin D; Freire, Mara G; Gomes, José R B; Coutinho, João A P

2014-05-01

The well-recognized advantageous properties of poly(ethylene glycol)s (PEGs) and ionic liquids (ILs) in the context of an increasing demand for safe and efficient biotechnological processes has led to a growing interest in the study of their combinations for a wide range of procedures within the framework of green chemistry. Recently, one of the most promising and attractive applications has been the novel IL/polymer-based aqueous biphasic systems (ABS) for the extraction and purification of biomolecules. There still lacks, however, a comprehensive picture of the molecular phenomena that control the phase behavior of these systems. In order to further delve into the interactions that govern the mutual solubilities between ILs and PEGs and the formation of PEG/IL-based ABS, (1)H NMR spectroscopy in combination with classical molecular dynamics (MD) simulations performed for binary mixtures of tetraethylene glycol (TEG) and 1-alkyl-3-methylimidazolium-chloride-based ILs and for the corresponding ternary TEG/IL/water solutions, at T = 298.15 K, were employed in this work. The results of the simulations show that the mutual solubilities of the ILs and TEG are mainly governed by the hydrogen bonds established between the chloride anion and the -OH group of the polymer in the binary systems. Additionally, the formation of IL/PEG-based ABS is shown to be controlled by a competition between water and chloride for the interactions with the hydroxyl group of TEG.

A quick responding quartz crystal microbalance sensor array based on molecular imprinted polyacrylic acids coating for selective identification of aldehydes in body odor.

PubMed

Jha, Sunil K; Hayashi, Kenshi

2015-03-01

In present work, a novel quartz crystal microbalance (QCM) sensor array has been developed for prompt identification of primary aldehydes in human body odor. Molecularly imprinted polymers (MIP) are prepared using the polyacrylic acid (PAA) polymer matrix and three organic acids (propenoic acid, hexanoic acid and octanoic acid) as template molecules, and utilized as QCM surface coating layer. The performance of MIP films is characterized by 4-element QCM sensor array (three coated with MIP layers and one with pure PAA for reference) dynamic and static responses to target aldehydes: hexanal, heptanal, and nonanal in single, binary, and tertiary mixtures at distinct concentrations. The target aldehydes were selected subsequent to characterization of body odor samples with solid phase-micro extraction gas chromatography mass spectrometer (SPME-GC-MS). The hexanoic acid and octanoic acid imprinted PAA exhibit fast response, and better sensitivity, selectivity and reproducibility than the propenoic acid, and non-imprinted PAA in array. The response time and recovery time for hexanoic acid imprinted PAA are obtained as 5 s and 12 s respectively to typical concentrations of binary and tertiary mixtures of aldehydes using the static response. Dynamic sensor array response matrix has been processed with principal component analysis (PCA) for visual, and support vector machine (SVM) classifier for quantitative identification of target odors. Aldehyde odors were identified successfully in principal component (PC) space. SVM classifier results maximum recognition rate 79% for three classes of binary odors and 83% including single, binary, and tertiary odor classes in 3-fold cross validation. Copyright © 2014 Elsevier B.V. All rights reserved.

Compression and compaction properties of plasticised high molecular weight hydroxypropylmethylcellulose (HPMC) as a hydrophilic matrix carrier.

PubMed

Hardy, I J; Cook, W G; Melia, C D

2006-03-27

The compression and compaction properties of plasticised high molecular weight USP2208 HPMC were investigated with the aim of improving tablet formation in HPMC matrices. Experiments were conducted on binary polymer-plasticiser mixtures containing 17 wt.% plasticiser, and on a model hydrophilic matrix formulation. A selection of common plasticisers, propylene glycol (PG) glycerol (GLY), dibutyl sebacate (DBS) and triacetin (TRI), were chosen to provide a range of plasticisation efficiencies. T(g) values of binary mixtures determined by Dynamic Mechanical Thermal Analysis (DMTA) were in rank order PG>GLY>DBS>TRI>unplasticised HPMC. Mean yield pressure, strain rate sensitivity (SRS) and plastic compaction energy were measured during the compression process, and matrix properties were monitored by tensile strength and axial expansion post-compression. Compression of HPMC:PG binary mixtures resulted in a marked reduction in mean yield pressure and a significant increase in SRS, suggesting a classical plasticisation of HPMC analogous to that produced by water. The effect of PG was also reflected in matrix properties. At compression pressures below 70 MPa, compacts had greater tensile strength than those from native polymer, and over the range 35 and 70 MPa, lower plastic compaction values showed that less energy was required to produce the compacts. Axial expansion was also reduced. Above 70 MPa tensile strength was limited to 3 MPa. These results suggest a useful improvement of HPMC compaction and matrix properties by PG plasticisation, with lowering of T(g) resulting in improved deformation and internal bonding. These effects were also detectable in the model formulation containing a minimal polymer content for an HPMC matrix. Other plasticisers were largely ineffective, matrix strength was poor and axial expansion high. The hydrophobic plasticisers (DBS, TRI) reduced yield pressure substantially, but were poor plasticisers and showed compaction mechanisms that could be attributed to phase separation. The effect of different plasticisers suggests that the deformation characteristics of this HPMC in the solid state is dominated by hydroxyl mediated bonding, rather than by hydrophobic interactions between methoxyl-rich regions.

Depletion forces drive polymer-like self-assembly in vibrofluidized granular materials†

PubMed Central

Nossal, Ralph

2011-01-01

Ranging from nano- to granular-scales, control of particle assembly can be achieved by limiting the available free space, for example by increasing the concentration of particles (“crowding”) or through their restriction to 2D environments. It is unclear, however, if self-assembly principles governing thermally-equilibrated molecules can also apply to mechanically-excited macroscopic particles in non-equilibrium steady-state. Here we show that low densities of vibrofluidized steel rods, when crowded by high densities of spheres and confined to quasi-2D planes, can self-assemble into linear polymer-like structures. Our 2D Monte Carlo simulations show similar finite sized aggregates in thermally equilibrated binary mixtures. Using theory and simulations, we demonstrate how depletion interactions create oriented “binding” forces between rigid rods to form these “living polymers.” Unlike rod-sphere mixtures in 3D that can demonstrate well-defined equilibrium phases, our mixtures confined to 2D lack these transitions because lower dimensionality favors the formation of linear aggregates, thus suppressing a true phase transition. The qualitative and quantitative agreement between equilibrium and granular patterning for these mixtures suggests that entropy maximization is the determining driving force for bundling. Furthermore, this study uncovers a previously unknown patterning behavior at both the granular and nanoscales, and may provide insights into the role of crowding at interfaces in molecular assembly. PMID:22039392

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

PubMed

Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

2015-06-01

An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design guidelines for adapting scientific research articles: An example from an introductory level, interdisciplinary program on soft matter

NASA Astrophysics Data System (ADS)

Langbeheim, Elon; Safran, Samuel A.; Yerushalmi, Edit

2013-01-01

We present design guidelines for using Adapted Primary Literature (APL) as part of current interdisciplinary topics to introductory physics students. APL is a text genre that allows students to comprehend a scientific article, while maintaining the core features of the communication among scientists, thus representing an authentic scientific discourse. We describe the adaptation of a research paper by Nobel Laureate Paul Flory on phase equilibrium in polymer-solvent mixtures that was presented to high school students in a project-based unit on soft matter. The adaptation followed two design strategies: a) Making explicit the interplay between the theory and experiment. b) Re-structuring the text to map the theory onto the students' prior knowledge. Specifically, we map the theory of polymer-solvent systems onto a model for binary mixtures of small molecules of equal size that was already studied in class.

Spontaneous formation of nanometer scale tubular vesicles in aqueous mixtures of lipid and block copolymer amphiphiles.

PubMed

Lim, Seng Koon; Wong, Andrew S W; de Hoog, Hans-Peter M; Rangamani, Padmini; Parikh, Atul N; Nallani, Madhavan; Sandin, Sara; Liedberg, Bo

2017-02-08

Many common amphiphiles self-assemble in water to produce heterogeneous populations of discrete and symmetric but polydisperse and multilamellar vesicles isolating the encapsulated aqueous core from the surrounding bulk. But when mixtures of amphiphiles of vastly different elastic properties co-assemble, their non-uniform molecular organization can stabilize lower symmetries and produce novel shapes. Here, using high resolution electron cryomicroscopy and tomography, we identify the spontaneous formation of a membrane morphology consisting of unilamellar tubular vesicles in dilute aqueous solutions of binary mixtures of two different amphiphiles of vastly different origins. Our results show that aqueous phase mixtures of a fluid-phase phospholipid and an amphiphilic block copolymer spontaneously assume a bimodal polymorphic character in a composition dependent manner: over a broad range of compositions (15-85 mol% polymer component), a tubular morphology co-exists with spherical vesicles. Strikingly, in the vicinity of equimolar compositions, an exclusively tubular morphology (L t ; diameter, ∼15 nm; length, >1 μm; core, ∼2.0 nm; wall, ∼5-6 nm) emerges in an apparent steady state. Theory suggests that the spontaneous stabilization of cylindrical vesicles, unaided by extraneous forces, requires a significant spontaneous bilayer curvature, which in turn necessitates a strongly asymmetric membrane composition. We confirm that such dramatic compositional asymmetry is indeed produced spontaneously in aqueous mixtures of a lipid and polymer through two independent biochemical assays - (1) reduction in the quenching of fluorophore-labeled lipids and (2) inhibition in the activity of externally added lipid-hydrolyzing phospholipase A2, resulting in a significant enrichment of the polymer component in the outer leaflet. Taken together, these results illustrate the coupling of the membrane shape with local composition through spontaneous curvature generation under conditions of asymmetric distribution of mixtures of disparate amphiphiles.

Electrical and optical properties of binary CNx nanocone arrays synthesized by plasma-assisted reaction deposition.

PubMed

Liu, Xujun; Guan, Leilei; Fu, Xiaoniu; Zhao, Yu; Wu, Jiada; Xu, Ning

2014-03-21

Light-absorbing and electrically conductive binary CNx nanocone (CNNC) arrays have been fabricated using a glow discharge plasma-assisted reaction deposition method. The intact CNNCs with amorphous structure and central nickel-filled pipelines could be vertically and neatly grown on nickel-covered substrates according to the catalyst-leading mode. The morphologies and composition of the as-grown CNNC arrays can be well controlled by regulating the methane/nitrogen mixture inlet ratio, and their optical absorption and resistivity strongly depend on their morphologies and composition. Beside large specific surface area, the as-grown CNNC arrays demonstrate high wideband absorption, good conduction, and nice wettability to polymer absorbers.

Dynamics of nanoparticles in complex fluids

NASA Astrophysics Data System (ADS)

Omari, Rami A.

Soft matter is a subfield of condensed matter including polymers, colloidal dispersions, surfactants, and liquid crystals. These materials are familiar from our everyday life- glues, paints, soaps, and plastics are examples of soft materials. Many phenomena in these systems have the same underlying physical mechanics. Moreover, it has been recognized that combinations of these systems, like for example polymers and colloids, exhibit new properties which are not found in each system separately. These mixed systems have a higher degree of complexity than the separate systems. In order to understand their behavior, knowledge from each subfields of soft matter has to be put together. One of these complex systems is the mixture of nanoparticles with macromolecules such as polymers, proteins, etc. Understanding the interactions in these systems is essential for solving various problems in technological and medical fields, such as developing high performance polymeric materials, chromatography, and drug delivery vehicles. The author of this dissertation investigates fundemental soft matter systems, including colloid dispersions in polymer solutions and binary mixture. The diffusion of gold nanoparticles in semidilute and entangled solutions of polystyrene (PS) in toluene were studied using fluorescence correlation spectroscopy (FCS). In our experiments, the particle radius (R ≈ 2.5 nm) was much smaller compared to the radius of gyration of the chain but comparable to the average mesh size of the fluctuating polymer network. The diffusion coefficient (D) of the particles decreased monotonically with polymer concentration and it can be fitted with a stretched exponential function. At high concentration of the polymer, a clear subdiffusive motion of the particles was observed. The results were compared with the diffusion of free dyes, which showed normal diffusive behavior for all concentrations. In another polymer solution, poly ethylene glycol (PEG) in water, the diffusion of the gold nanoparticles depends on the dimentionless length scale R/zeta, where R is the radius of the nanoparticle and zeta is the average mesh size of the fluctuating polymer network. FCS were used to study the critical adsorption on curved surfaces by utilizing spherical nanoparticles immersed in a critical binary liquid mixture of 2,6 lutidine + water. The temperature dependence of the adsorbed film thickness and excess adsorption was determined from FCS measurements of the enlarged effective hydrodynamic radius of the particles. Our results indicated that the adsorbed film thickness is of the order of correlation length associated with concentration fluctuations. The excess adsorption per unit area increases following a power law in reduced temperature with an exponent of -1, which is the mean-field value for the bulk susceptibility exponent. The kinetics of adsorption of gold nanoparticles in polymer solutions on silicon substrate was studied using ellipsometry by measuring the thickness of the adsorbed layer versus time. The data showed an exponential growth with relaxation time constants, which is proportional to the diffusion of the gold nanoparticles in polymer solution.

Excited-state proton transfer dynamics of firefly's chromophore D-luciferin in DMSO-water binary mixture.

PubMed

Kuchlyan, Jagannath; Banik, Debasis; Roy, Arpita; Kundu, Niloy; Sarkar, Nilmoni

2014-12-04

In this article we have investigated intermolecular excited-state proton transfer (ESPT) of firefly's chromophore D-luciferin in DMSO-water binary mixtures using steady-state and time-resolved fluorescence spectroscopy. The unusual behavior of DMSO-water binary mixture as reported by Bagchi et al. (J. Phys. Chem. B 2010, 114, 12875-12882) was also found using D-luciferin as intermolecular ESPT probe. The binary mixture has given evidence of its anomalous nature at low mole fractions of DMSO (below XD = 0.4) in our systematic investigation. Upon excitation of neutral D-luciferin molecule, dual fluorescence emissions (protonated and deprotonated form) are observed in DMSO-water binary mixture. A clear isoemissive point in the time-resolved area normalized emission spectra further indicates two emissive species in the excited state of D-luciferin in DMSO-water binary mixture. DMSO-water binary mixtures of different compositions are fascinating hydrogen bonding systems. Therefore, we have observed unusual changes in the fluorescence emission intensity, fluorescence quantum yield, and fluorescence lifetime of more hydrogen bonding sensitive anionic form of D-luciferin in low DMSO content of DMSO-water binary mixture.

Evaluation of the deformation behavior of binary systems of methacrylic acid copolymers and hydroxypropyl methylcellulose using a compaction simulator.

PubMed

Tatavarti, Aditya S; Muller, Francis X; Hoag, Stephen W

2008-02-04

Methacrylic acid copolymers have been shown to enhance release of weakly basic drugs from rate controlling polymer matrices through the mechanism of microenvironmental pH modulation. Since these matrices are typically formed through a compaction process, an understanding of the deformation behavior of these polymers in there neat form and in combination with rate controlling polymers such as HPMC is critical to their successful formulation. Binary mixes of two methacrylic acid copolymers, Eudragit L100 and L100-55 in combination with HPMC K4M were subjected to compaction studies on a compaction simulator. The deformation behavior of the powder mixes was analyzed based on pressure-porosity relationships, strain rate sensitivity (SRS), residual die wall force data and work of compaction. Methacrylic acid copolymers, L100-55 and L-100 and the hydrophilic polymer, HPMC K4M exhibited Heckel plots representative of plastic deformation although L-100 exhibited significantly greater resistance to densification as evident from the high yield pressure values ( approximately 120MPa). The yield pressures for the binary mixes were linearly related to the weight fractions of the components. All powder mixes exhibited significant speed sensitivity with SRS values ranging from 21.7% to 42.4%. The residual die-wall pressures indicated that at slow speeds (1mm/s) and at lower pressures (<150MPa), HPMC possesses significant elastic behavior. However, the good compacts formed at this punch speed indicate significant plastic deformation and bond formation which is able to predominate over the elastic recovery component. The apparent mean yield pressure values, the residual die-wall forces and the net work of compaction exhibited a linear relationship with mixture composition, thereby indicating predictability of these parameters based on the behavior of the neat materials.

Viscosities of nonelectrolyte liquid mixtures. III. Selected binary and quaternary mixtures

NASA Astrophysics Data System (ADS)

Wakefield, D. L.

1988-05-01

This paper is the final in a series of three viscosity and density studies of pure n-alkanes and selected binary and quaternary mixtures. A standard U-tube viscometer was used for viscosity measurements, and a Pyrex flask-type pycnometer was used for density determinations. Results are given here for pure alkane and selected binary mixtures of n-tetradecane + n-octane, for selected quaternary mixtures of n-hexadecane + n-dodecane + n-decane + n-hexane, and for pure and selected quaternary mixtures of n-hexadecane + n-dodecane + n-nonane + n-heptane at 303.16 and 308.16 K. The principle of congruence was tested, as was the Grunberg and Nissan equation, as they have been shown to be useful as prediction techniques for other n-alkane binary mixtures. Comparisons were made between the two groups of quaternary alkane mixtures and the binary n-tetradecane + n-octane mixtures of the same “pseudo” composition to understand better the dependence of mixture viscosities on the composition parameter.

Effect of Water on the Thermo-Mechanical Behavior of Carbon Cloth Phenolic

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.; Stokes, Eric; Baker, Eric H.

2011-01-01

The results of thermo-mechanical experiments, which were conducted previously by one of the authors, are reviewed. The strain in the direction normal to the fabric plane was measured as a function of temperature for a variety of initial moisture contents and heating rates. In this paper, the general features of the thermo-mechanical response are discussed and the effect of heating rate and initial moisture content are highlighted. The mechanical interaction between the phenolic polymer and water trapped within its free volumes as the polymer is heated to high temperatures is discussed. An equation for the internal stresses which are generated within the polymer due to trapped water is obtained from the total stress expression for a binary mixture of polymer and water. Numerical solutions for moisture diffusion in the thermo-mechanical experiments were performed and the results of these solutions are presented. The results of the moisture diffusion solutions help to explain the effects of heating rate and moisture content on the strain behavior normal to the fabric plane.

Influence of protein size on surface-enhanced Raman scattering (SERS) spectra in binary protein mixtures.

PubMed

Avci, Ertug; Culha, Mustafa

2014-01-01

The size-dependent interactions of eight blood proteins with silver nanoparticles (AgNPs) in their binary mixtures were investigated using surface-enhanced Raman scattering (SERS). Principal component analysis (PCA) was performed on the SERS spectra of each binary mixture, and the differentiation ability of the mixtures was tested. It was found that the effect of relative concentration change on the SERS spectra of the binary mixtures of small proteins could be detected using PCA. However, this change was not observed with the binary mixtures of large proteins. This study demonstrated that the relative interactions of the smaller proteins with an average size of 50 nm AgNPs smaller than the large proteins could be monitored, and this information can be used for the detection of proteins in protein mixtures.

Wetting-layer formation mechanisms of surface-directed phase separation under different quench depths with off-critical compositions in polymer binary mixture

NASA Astrophysics Data System (ADS)

Yan, Li-Tang; Xie, Xu-Ming

2007-02-01

Focusing on the off-critical condition, the quench depth dependence of surface-directed phase separation in the polymer binary mixture is numerically investigated by combination of the Cahn-Hilliard-Cook theory and the Flory-Huggins-de Gennes theory. Two distinct situations, i.e., for the wetting, the minority component is preferred by the surface and the majority component is preferred by the surface, are discussed in detail. The simulated results show that the formation mechanism of the wetting layer is affected by both the quench depth and the off-critical extent. Moreover, a diagram, illustrating the formation mechanisms of the wetting layer with various quench depths and compositions, is obtained on the basis of the simulated results. It is found that, when the minority component is preferred by the surface, the growth of the wetting layer can exhibit pure diffusion limited growth law, logarithmic growth law, and Lifshitz-Slyozov growth law. However, when the majority component is preferred by the surface, the wetting layer always grows logarithmically, regardless of the quench depth and the off-critical extent. It is interesting that the surface-induced nucleation can be observed in this case. The simulated results demonstrate that the surface-induced nucleation only occurs below a certain value of the quench depth, and a detailed range about it is calculated and indicated. Furthermore, the formation mechanisms of the wetting layer are theoretically analyzed in depth by the chemical potential gradient.

ThermoData Engine Database - Pure Compounds and Binary Mixtures

National Institute of Standards and Technology Data Gateway

SRD 103b NIST ThermoData Engine Version 6.0 - Pure CompoThermoData Engine Database - Pure Compounds and Binary Mixtures (PC database for purchase)   This database contains property data for more than 21,000 pure compounds, 37,500 binary mixtures, 10,000 ternary mixtures, and 6,000 chemical reactions.

Suppression of turbulent energy cascade due to phase separation in homogenous binary mixture fluid

NASA Astrophysics Data System (ADS)

Takagi, Youhei; Okamoto, Sachiya

2015-11-01

When a multi-component fluid mixture becomes themophysically unstable state by quenching from well-melting condition, phase separation due to spinodal decomposition occurs, and a self-organized structure is formed. During phase separation, free energy is consumed for the structure formation. In our previous report, the phase separation in homogenous turbulence was numerically simulated and the coarsening process of phase separation was discussed. In this study, we extended our numerical model to a high Schmidt number fluid corresponding to actual polymer solution. The governing equations were continuity, Navier-Stokes, and Chan-Hiliard equations as same as our previous report. The flow filed was an isotropic homogenous turbulence, and the dimensionless parameters in the Chan-Hilliard equation were estimated based on the thermophysical condition of binary mixture. From the numerical results, it was found that turbulent energy cascade was drastically suppressed in the inertial subrange by phase separation for the high Schmidt number flow. By using the identification of turbulent and phase separation structure, we discussed the relation between total energy balance and the structures formation processes. This study is financially supported by the Grand-in-Aid for Young Scientists (B) (No. T26820045) from the Ministry of Education, Cul-ture, Sports, Science and Technology of Japan.

Assessment and prediction of joint algal toxicity of binary mixtures of graphene and ionic liquids.

PubMed

Wang, Zhuang; Zhang, Fan; Wang, Se; Peijnenburg, Willie J G M

2017-10-01

Graphene and ionic liquids (ILs) released into the environment will interact with each other. So far however, the risks associated with the concurrent exposure of biota to graphene and ILs in the environment have received little attention. The research reported here focused on observing and predicting the joint toxicity effects in the green alga Scenedesmus obliquus exposed to binary mixtures of intrinsic graphene (iG)/graphene oxide (GO) and five ILs of varying anionic and cationic types. The isolated ILs in the binary mixtures were the main contributors to toxicity. The binary GO-IL mixtures resulted in more severe joint toxicity than the binary iG-IL mixtures, irrespective of mixture ratios. The mechanism of the joint toxicity may be associated with the adsorption capability of the graphenes for the ILs, the dispersion stability of the graphenes in aquatic media, and modulation of the binary mixtures-induced oxidative stress. A toxic unit assessment showed that the graphene and IL toxicities were additive at low concentration of the mixtures but antagonistic at high concentration of the mixtures. Predictions made using the concentration addition and independent action models were close to the observed joint toxicities regardless of mixture types and mixture ratios. These findings provide new insights that are of use in the risk assessment of mixtures of engineered nanoparticles and other environmentally relevant contaminants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dielectric and spectroscopic study of binary mixture of Acrylonitrile with Chlorobenzene

NASA Astrophysics Data System (ADS)

Deshmukh, Snehal D.; Pattebahadur, K. L.; Mohod, A. G.; Undre, P. B.; Patil, S. S.; Khirade, P. W.

2018-05-01

In this paper, study of binary mixture of Acrylonitrile (ACN) with Chlorobenzene (CBZ) has been carried out at eleven concentrations at room temperature. The determined Dielectric Constant (ɛ0) Density (ρ) and Refractive index (nD) values of binary mixture are used to calculate the excess properties of mixture over the entire composition range and fitted to the Redlich-Kister equation. From the above parameters, intermolecular interaction and dynamics of molecules of binary mixture at molecular level are discussed. The Conformational analysis of the intermolecular interaction between Acrylonitrile and Chlorobenzene is supported by the FTIR spectra.

Binary and ternary gas mixtures for use in glow discharge closing switches

DOEpatents

Hunter, Scott R.; Christophorou, Loucas G.

1990-01-01

Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue of the combined physio-electric properties of the mixture components.

Crystallization features of normal alkanes in confined geometry.

PubMed

Su, Yunlan; Liu, Guoming; Xie, Baoquan; Fu, Dongsheng; Wang, Dujin

2014-01-21

How polymers crystallize can greatly affect their thermal and mechanical properties, which influence the practical applications of these materials. Polymeric materials, such as block copolymers, graft polymers, and polymer blends, have complex molecular structures. Due to the multiple hierarchical structures and different size domains in polymer systems, confined hard environments for polymer crystallization exist widely in these materials. The confined geometry is closely related to both the phase metastability and lifetime of polymer. This affects the phase miscibility, microphase separation, and crystallization behaviors and determines both the performance of polymer materials and how easily these materials can be processed. Furthermore, the size effect of metastable states needs to be clarified in polymers. However, scientists find it difficult to propose a quantitative formula to describe the transition dynamics of metastable states in these complex systems. Normal alkanes [CnH2n+2, n-alkanes], especially linear saturated hydrocarbons, can provide a well-defined model system for studying the complex crystallization behaviors of polymer materials, surfactants, and lipids. Therefore, a deeper investigation of normal alkane phase behavior in confinement will help scientists to understand the crystalline phase transition and ultimate properties of many polymeric materials, especially polyolefins. In this Account, we provide an in-depth look at the research concerning the confined crystallization behavior of n-alkanes and binary mixtures in microcapsules by our laboratory and others. Since 2006, our group has developed a technique for synthesizing nearly monodispersed n-alkane containing microcapsules with controllable size and surface porous morphology. We applied an in situ polymerization method, using melamine-formaldehyde resin as shell material and nonionic surfactants as emulsifiers. The solid shell of microcapsules can provide a stable three-dimensional (3-D) confining environment. We have studied multiple parameters of these microencapsulated n-alkanes, including surface freezing, metastability of the rotator phase, and the phase separation behaviors of n-alkane mixtures using differential scanning calorimetry (DSC), temperature-dependent X-ray diffraction (XRD), and variable-temperature solid-state nuclear magnetic resonance (NMR). Our investigations revealed new direct evidence for the existence of surface freezing in microencapsulated n-alkanes. By examining the differences among chain packing and nucleation kinetics between bulk alkane solid solutions and their microencapsulated counterparts, we also discovered a mechanism responsible for the formation of a new metastable bulk phase. In addition, we found that confinement suppresses lamellar ordering and longitudinal diffusion, which play an important role in stabilizing the binary n-alkane solid solution in microcapsules. Our work also provided new insights into the phase separation of other mixed system, such as waxes, lipids, and polymer blends in confined geometry. These works provide a profound understanding of the relationship between molecular structure and material properties in the context of crystallization and therefore advance our ability to improve applications incorporating polymeric and molecular materials.

The effective colloid interaction in the Asakura-Oosawa model. Assessment of non-pairwise terms from the virial expansion.

PubMed

Santos, Andrés; López de Haro, Mariano; Fiumara, Giacomo; Saija, Franz

2015-06-14

The relevance of neglecting three- and four-body interactions in the coarse-grained version of the Asakura-Oosawa model is examined. A mapping between the first few virial coefficients of the binary nonadditive hard-sphere mixture representative of this model and those arising from the coarse-grained (pairwise) depletion potential approximation allows for a quantitative evaluation of the effect of such interactions. This turns out to be especially important for large size ratios and large reservoir polymer packing fractions.

Polymers imprinted with PAH mixtures--comparing fluorescence and QCM sensors.

PubMed

Lieberzeit, Peter A; Halikias, Konstantin; Afzal, Adeel; Dickert, Franz L

2008-12-01

Molecular imprinting with binary mixtures of different polycyclic aromatic hydrocarbons (PAH) is a tool for design of chemically highly sensitive layers for detection of these analytes. Sensor responses increase by one order of magnitude compared with layers imprinted with one type of template. Detection limits, e.g. for pyrene, reach down to 30 ng L(-1) in water, as could be observed with a naphthalene and pyrene-imprinted polyurethane. Comparing sensor characteristics obtained by QCM and fluorescence reveals different saturation behaviours indicating that, first, single PAH molecules occupy the interaction centres followed by gradual excimer incorporation at higher concentrations finally leading to substantial quenching, when all accessible cavities are occupied. The plateau in the mass-sensitive measurements suggests that up to 80% of the cavities generated in the MIP are re-occupied. Displacement measurements between chrysene and pyrene revealed that for imprinted layers with very high pyrene sensitivities the signals of both PAH are additive, whereas in materials with lower pyrene uptake the two analytes replace each other in the interaction sites of the polymer.

Interactions between carbamazepine and polyethylene glycol (PEG) 6000: characterisations of the physical, solid dispersed and eutectic mixtures.

PubMed

Naima, Z; Siro, T; Juan-Manuel, G D; Chantal, C; René, C; Jerome, D

2001-02-01

The influence of a hydrophilic carrier (PEG 6000) on the polymorphism of carbamazepine, an antiepileptic drug, was investigated in binary physical mixtures and solid dispersions by means of differential scanning calorimetry (DSC), thermal gravimetry, hot-stage microscopy (HSM), and X-ray diffractometry, respectively. This study provides also an attempt to develop a method to calculate more precisely the eutectic composition. In rather ideal physical mixtures, carbamazepine was found as monoclinic Form III. In solid dispersions, the drug was found to crystallize as trigonal Form II; a eutectic invariant in the PEG 6000-rich composition domain (6% of carbamazepine mass) was evidenced by DSC experiments and confirmed by HSM observations. In the binary phase diagram the ideal carbamazepine liquidus curve was located at temperatures higher than the respective experimental ones. This suggests that drug can be maintained in the liquid state in the temperature-mass fraction (T--x) region between the two carbamazepine liquidus curves. This indicates in turn that attractive interactions occur between carbamazepine and PEG 6000-chains. These interactions have been also claimed to prevent carbamazepine from degradation into iminostilbene (a compound resulting from the chemical degradation of carbamazepine which is postulated to be responsible for the idiosyncratic toxicity of the drug) and thought to lead to the crystallization of metastable Carbamazepine II from melt. The negative excess entropy for eutectic mixtures indicated that the drug crystals are finely dispersed in the bulk of polymer chains.

Investigation of intermolecular interaction of binary mixture of acrylonitrile with bromobenzene

NASA Astrophysics Data System (ADS)

Deshmukh, S. D.; Pattebahadur, K. L.; Mohod, A. G.; Patil, S. S.; Khirade, P. W.

2018-04-01

In this paper, study of binary mixture of Acrylonitrile (ACN)with Bromobenzene(BB) has been carried out at eleven concentrations at room temperature. The determined density(ρ) and refractive index (nD) values of binary mixture are used to calculate the excess properties of mixture over the entire composition range. The aforesaid parameters are used to calculate excess parameters and fitted to the Redlich-Kister equation to determine the bj coefficients. From the above parameters, intermolecular interaction and dynamics of molecules of binary mixture at molecular level are discussed. The Conformational analysis of the intermolecular interaction between Acrylonitrile and Bromobenzene is supported by the FTIR spectra.

Binary and ternary gas mixtures for use in glow discharge closing switches

DOEpatents

Hunter, S.R.; Christophorou, L.G.

1988-04-27

Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

Recognition by Rats of Binary Taste Solutions and Their Components.

PubMed

Katagawa, Yoshihisa; Yasuo, Toshiaki; Suwabe, Takeshi; Yamamura, Tomoki; Gen, Keika; Sako, Noritaka

2016-09-13

This behavioral study investigated how rats conditioned to binary mixtures of preferred and aversive taste stimuli, respectively, responded to the individual components in a conditioned taste aversion (CTA) paradigm. The preference of stimuli was determined based on the initial results of 2 bottle preference test. The preferred stimuli included 5mM sodium saccharin (Sacc), 0.03M NaCl (Na), 0.1M Na, 5mM Sacc + 0.03M Na, and 5mM Sacc + 0.2mM quinine hydrochloride (Q), whereas the aversive stimuli tested were 1.0M Na, 0.2mM Q, 0.3mM Q, 5mM Sacc + 1.0M Na, and 5mM Sacc + 0.3mM Q. In CTA tests where LiCl was the unconditioned stimulus, the number of licks to the preferred binary mixtures and to all tested preferred components were significantly less than in control rats. No significant difference resulted between the number of licks to the aversive binary mixtures or to all tested aversive components. However, when rats pre-exposed to the aversive components contained of the aversive binary mixtures were conditioned to these mixtures, the number of licks to all the tested stimuli was significantly less than in controls. Rats conditioned to components of the aversive binary mixtures generalized to the binary mixtures containing those components. These results suggest that rats recognize and remember preferred and aversive taste mixtures as well as the preferred and aversive components of the binary mixtures, and that pre-exposure before CTA is an available method to study the recognition of aversive taste stimuli. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Widom Lines in Binary Mixtures of Supercritical Fluids.

PubMed

Raju, Muralikrishna; Banuti, Daniel T; Ma, Peter C; Ihme, Matthias

2017-06-08

Recent experiments on pure fluids have identified distinct liquid-like and gas-like regimes even under supercritical conditions. The supercritical liquid-gas transition is marked by maxima in response functions that define a line emanating from the critical point, referred to as Widom line. However, the structure of analogous state transitions in mixtures of supercritical fluids has not been determined, and it is not clear whether a Widom line can be identified for binary mixtures. Here, we present first evidence for the existence of multiple Widom lines in binary mixtures from molecular dynamics simulations. By considering mixtures of noble gases, we show that, depending on the phase behavior, mixtures transition from a liquid-like to a gas-like regime via distinctly different pathways, leading to phase relationships of surprising complexity and variety. Specifically, we show that miscible binary mixtures have behavior analogous to a pure fluid and the supercritical state space is characterized by a single liquid-gas transition. In contrast, immiscible binary mixture undergo a phase separation in which the clusters transition separately at different temperatures, resulting in multiple distinct Widom lines. The presence of this unique transition behavior emphasizes the complexity of the supercritical state to be expected in high-order mixtures of practical relevance.

Solidification phenomena of binary organic mixtures

NASA Technical Reports Server (NTRS)

Chang, K.

1982-01-01

The coalescence rates and motion of liquid bubbles in binary organic mixtures were studied. Several factors such as temperature gradient, composition gradient, interfacial tension, and densities of the two phases play important roles in separation of phases of immiscible liquids. An attempt was made to study the effect of initial compositions on separation rates of well-dispersed organic mixtures at different temperatures and, ultimately, on the homogeneity of solidification of the immiscible binary organic liquids. These organic mixtures serve as models for metallic pseudo binary systems under study. Two specific systems were investigated: ethyl salicylate - diethyl glycol and succinonitrile - water.

Phase behaviour of the symmetric binary mixture from thermodynamic perturbation theory.

PubMed

Dorsaz, N; Foffi, G

2010-03-17

We study the phase behaviour of symmetric binary mixtures of hard core Yukawa (HCY) particles via thermodynamic perturbation theory (TPT). We show that all the topologies of phase diagram reported for the symmetric binary mixtures are correctly reproduced within the TPT approach. In a second step we use the capability of TPT to be straightforwardly extended to mixtures that are nonsymmetric in size. Starting from mixtures that belong to the different topologies of symmetric binary mixtures we investigate the effect on the phase behaviour when an asymmetry in the diameters of the two components is introduced. Interestingly, when the energy of interaction between unlike particles is weaker than the interaction between like particles, the propensity for the solution to demix is found to increase strongly with size asymmetry.

A deeper insight into an intriguing acetonitrile-water binary mixture: synergistic effect, dynamic Stokes shift, fluorescence correlation spectroscopy, and NMR studies.

PubMed

Koley, Somnath; Ghosh, Subhadip

2016-11-30

An insight study reveals the strong synergistic solvation behaviours from reporter dye molecules within the acetonitrile (ACN)-water (WT) binary mixture. Synergism of a binary mixture refers to some unique changes of the physical and thermodynamic properties of the solvent mixture, originating from the interactions among its cosolvents, which are absent within the pure cosolvents. Synergistic solvation of a binary mixture is likely to be fundamental for greater stabilization of an excited state solute dipole; at least to some extent greater as compared to one stabilized by any of its cosolvents alone. A dynamic Stokes shift due to the solvation of an excited dipole in the ACN-WT binary mixture is found to be highly relevant to the ground state physical properties of the solute molecule (polarity, hydrophilicity, acidity, etc.). Largely different solvation times in the ACN-WT mixture are observed from different dye molecules with widely varying polarities. However, earlier study shows that dye molecules, irrespective of their varying polarities, exhibit very similar solvation times within a pure solvent (J. Phys. Chem. B, 2014, 118, 7577-7785). On further study with fluorescence correlation spectroscopy (FCS) we observed that, unlike the translational diffusion coefficient (D t ) of a dye molecule within a pure solvent, which remains the same irrespective of the location of the dye molecule inside the solvent, a broad distribution among the D t values of a dye molecule is obtained from different locations within the ACN-WT binary mixture. Lastly our 1 H NMR study in the ACN-WT binary mixture shows the existence of strong hydrogen bond interactions among the cosolvents in the ACN-WT mixture.

Bactericidal action of binary and ternary mixtures of carvacrol, thymol, and eugenol against Listeria innocua.

PubMed

García-García, Rebeca; López-Malo, Aurelio; Palou, Enrique

2011-03-01

The bactericidal effect of 3 natural agents (carvacrol, thymol, and eugenol) was evaluated as well as their binary and ternary mixtures on Listeria innocua inactivation in liquid model systems. Minimal bactericidal concentrations (MBC) of these agents were determined, and then binary and ternary mixtures were evaluated. Culture media were inoculated with L. innocua and incubated for 72 h at 35 °C. Turbidity of studied systems were determined every 24 h. The most effective individual antimicrobial agent was carvacrol, followed by thymol and then eugenol with MBCs of 150, 250, and 450 mg kg(-1), respectively. It was observed that the most effective binary mixture was 75 mg kg(-1) carvacrol and 62.5 mg kg(-1) thymol. Furthermore, the ternary mixture carvacrol-thymol-eugenol in concentrations of 75, 31.25, and 56.25 mg kg(-1), correspondingly, was the most effective for L. innocua inactivation. Several binary and ternary mixtures of these 3 natural antimicrobial agents worked adequately to inactivate L. innocua.

Experimental study on thermal storage performance of binary mixtures of fatty acids

NASA Astrophysics Data System (ADS)

Yan, Quanying; Zhang, Jing; Liu, Chao; Liu, Sha; Sun, Xiangyu

2018-02-01

We selected five kinds of fatty acids including the capric acid, stearic acid, lauric acid, palmitic acid and myristic acid and mixed them to prepare10 kinds of binary mixtures of fatty acids according to the predetermined proportion,tested the phase change temperature and latent heat of mixtures by differential scanning calorimetry(DSC). In order to find the fatty acid mixture which has suitable phase change temperature, the larger phase change latent heat and can be used for phase change wall. The results showed that the phase change temperature and latent heats of the binary mixtures of fatty acids decreased compared with the single component;The phase change temperature of the binary mixtures of fatty acids containing capric acid were lower, the range was roughly 20∼30°C,and latent heat is large,which are ideal phase change materials for phase change wall energy storage;The phase change temperature of the binary mixtures consisting of other fatty acids were still high,didn’t meet the temperature requirements of the wall energy storage.

A Mechanistic Understanding of a Binary Additive System to Synergistically Boost Efficiency in All-Polymer Solar Cells

PubMed Central

Kim, Yu Jin; Ahn, Sunyong; Wang, Dong Hwan; Park, Chan Eon

2015-01-01

All-polymer solar cells are herein presented utilizing the PBDTTT-CT donor and the P(NDI2OD-T2) acceptor with 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) binary solvent additives. A systematic study of the polymer/polymer bulk heterojunction photovoltaic cells processed from the binary additives revealed that the microstructures and photophysics were quite different from those of a pristine system. The combination of DIO and CN with a DIO/CN ratio of 3:1 (3 vol% DIO, 1 vol% CN and 96 vol% o-DCB) led to suitable penetrating polymer networks, efficient charge generation and balanced charge transport, which were all beneficial to improving the efficiency. This improvement is attributed to increase in power conversion efficiency from 2.81% for a device without additives to 4.39% for a device with the binary processing additives. A detailed investigation indicates that the changes in the polymer:polymer interactions resulted in the formation of a percolating nasnoscale morphology upon processing with the binary additives. Depth profile measurements with a two-dimensional grazing incidence wide-angle X-ray scattering confirm this optimum phase feature. Furthermore impedance spectroscopy also finds evidence for synergistically boosting the device performance. PMID:26658472

Dielectric and physiochemical study of binary mixture of nitrobenzene with toluene

NASA Astrophysics Data System (ADS)

Mohod, Ajay G.; Deshmukh, S. D.; Pattebahadur, K. L.; Undre, P. B.; Patil, S. S.; Khirade, P. W.

2018-05-01

This paper presents the study of binary mixture of Nitrobenzene (NB) with Toluene (TOL) for eleven different concentrations at room temperature. The determined Dielectric Constant (ɛ0) Density (ρ) and Refractive index (nD) values of binary mixture are used to calculate the excess properties i.e. Excess Dielectric Constant (ɛ0E), Excess Molar Volume (VmE), Excess Refractive Index (nDE) and Excess Molar Refraction (RmE) of mixture over the entire composition range and fitted to the Redlich-Kister equation. The Kirkwood Correlation Factor (geff) and other parameters were used to discuss the information about the orientation of dipoles and the solute-solvent interaction of binary mixture at molecular level over the entire range of concentration.

Bead-bead interaction parameters in dissipative particle dynamics: Relation to bead-size, solubility parameter, and surface tension

NASA Astrophysics Data System (ADS)

Maiti, Amitesh; McGrother, Simon

2004-01-01

Dissipative particle dynamics (DPD) is a mesoscale modeling method for simulating equilibrium and dynamical properties of polymers in solution. The basic idea has been around for several decades in the form of bead-spring models. A few years ago, Groot and Warren [J. Chem. Phys. 107, 4423 (1997)] established an important link between DPD and the Flory-Huggins χ-parameter theory for polymer solutions. We revisit the Groot-Warren theory and investigate the DPD interaction parameters as a function of bead size. In particular, we show a consistent scheme of computing the interfacial tension in a segregated binary mixture. Results for three systems chosen for illustration are in excellent agreement with experimental results. This opens the door for determining DPD interactions using interfacial tension as a fitting parameter.

Dielectric and Excess Properties of Glycols with Formamide Binary Mixtures at Different Temperatures

NASA Astrophysics Data System (ADS)

Navarkhele, V. V.

2018-07-01

Dielectric constant measurements of glycol-formamide binary solutions with various concentrations have been carried out at different temperatures. The dielectric measurement has been achieved at 100 MHz frequency using a sensor which is based on frequency domain reflectomery technique. The excess dielectric constant, Kirkwood correlation factor and Bruggeman factor has also been reported for the binary mixtures. The results show that the dielectric constant of the mixtures increases with increase in the volume fraction of formamide and decreases with increase in temperature. The study also confirms the presence of intermolecular interaction, hydrogen bonding and orientation of the dipoles in the binary mixtures.

Dielectric properties of binary mixtures of ethylene glycol monophenyl ether and methanol

NASA Astrophysics Data System (ADS)

Vaghela, K. C.; Vankar, H. P.; Trivedi, C. M.; Rana, V. A.

2017-05-01

Static permittivity (ɛ0) and permittivity at optical frequency (ɛ∞) of ethylene glycol monophenyl ether (EGMPE), methanol (MeOH) and their binary mixtures of varying concentrations have been measured at room temperature (T=299.15 K). The investigation showed a systematic change in permittivity with change in concentration of MeOH in binary mixture system. Measured data have been used to calculate the various dielectric parameters such as E E excess static permittivity (ɛ0E), excess permittivity at optical frequency (ɛ∞E) and Bruggeman factor (fB). Determined parameters provided some information about the molecular interaction among the molecular species of the binary mixtures.

Contrasting two different interpretations of the dynamics in binary glass forming mixtures

NASA Astrophysics Data System (ADS)

Valenti, S.; Capaccioli, S.; Ngai, K. L.

2018-02-01

In a series of papers on binary glass-forming mixtures of tripropyl phosphate (TPP) with polystyrene (PS), Kahlau et al. [J. Chem. Phys. 140, 044509 (2014)] and Bock et al. [J. Chem. Phys. 139, 064508 (2013); J. Chem. Phys. 140, 094505 (2014); and J. Non-Cryst. Solids 407, 88-97 (2015)] presented the data on the dynamics of the two components studied over the entire composition range by several experimental methods. From these sets of data, obtained by multiple experimental techniques on mixtures with a large difference ΔTg ≈ 200 K between the glass transition temperatures of two starting glass formers, they obtained two α-relaxations, α1 and α2. The temperature dependence of the slower α1 is Vogel-Fulcher like, but the faster α2 is Arrhenius. We have re-examined their data and show that their α2-relaxation is the Johari-Goldstein (JG) β-relaxation with Arrhenius T-dependence admixed with a true α2-relaxation having a stronger temperature dependence. In support of our interpretation of their data, we made dielectric measurements at elevated pressures P to show that the ratio of the α1 and α2 relaxation times, τα1(T,P)/τα2(T,P), is invariant to variations of T and P, while τα1(T,P) is kept constant. This property proves unequivocally that the α2-relaxation is the JG β-relaxation, the precursor of the α1-relaxation. Subsequently, the true but unresolved α2-relaxation is recovered, and its relaxation times with much stronger temperature dependence are deduced, as expected for the α-relaxation of the TPP component. The results are fully compatible with those found in another binary mixture of methyltetrahydrofuran with tristyrene and PS with ΔTg ≈ 283 K, even larger than ΔTg ≈ 200 K of the mixture of TPP with PS, and in several polymer blends. The contrast between the two very different interpretations brought out in this paper is deemed beneficial for further progress in this research area.

Effect of CMC addition on steady and dynamic shear rheological properties of binary systems of xanthan gum and guar gum.

PubMed

Bak, J H; Yoo, B

2018-04-12

The effect of CMC on the steady and dynamic shear rheological properties of binary mixtures of XG and GG was examined at different mixing ratios. All XG-GG-CMC ternary mixtures had high shear-thinning behavior and the n value of the sample with 5% CMC was the smallest compared with those of other samples. A marked increase in K and η a,50 values was observed for ternary mixtures at a lower content (5%) of CMC, indicating that the synergistic interactions of the XG-GG binary mixture were affected by the content of CMC. The effect of temperature on the η a,50 was well described by the Arrhenius equation for all samples. The activation energy values of all ternary gum mixtures are higher than that of binary gum mixture, and these values also decreased with an increase in CMC content from 5 to 15%. The dynamic moduli of ternary gum mixtures decreased with an increase in CMC content. The tan δ value of the ternary gum mixture with 5% CMC was much lower than those of other ternary mixtures. In general, these results suggest that the flow and dynamic shear rheological properties of XG-GG binary mixtures are strongly influenced by a small addition of CMC. Copyright © 2018. Published by Elsevier B.V.

Effect of molecular weight, temperature, and additives on the moisture sorption properties of polyethylene glycol.

PubMed

Baird, Jared A; Olayo-Valles, Roberto; Rinaldi, Carlos; Taylor, Lynne S

2010-01-01

Polyethylene glycol (PEG) is a hygroscopic polymer that undergoes the phenomenon of deliquescence once a critical relative humidity (RH(0)) is reached. The purpose of this study was to test the hypothesis that the deliquescence behavior of PEG will be affected by the polymer molecular weight, temperature, and the presence of additives. The deliquescence relative humidity for single component (RH(0)) and binary mixtures (RH(0,mix)) were measured using an automated gravimetric moisture analyzer at 25 and 40 degrees C. Changes in PEG crystallinity after exposure to moisture were qualitatively assessed using powder X-ray diffraction (PXRD). Optical microscopy was used to visually observe the deliquescence phenomenon. For single component systems, decreasing PEG MW and elevating the temperature resulted in a decrease in the observed RH(0). Physical mixtures of acetaminophen and anhydrous citric acid with both PEG 3350 and PEG 100,000 exhibited deliquescence (RH(0,mix)) at a relative humidity below that of either individual component. Qualitative changes in crystallinity were observed from the X-ray diffractograms for each PEG MW grade at high relative humidities, indicating that phase transformation (deliquescence) of the samples had occurred. In conclusion, it was found that the deliquescence behavior of PEG was affected by the polymer MW, temperature, and the presence of additives. This phenomenon may have important implications for the stability of PEG containing formulations.

Study of intermolecular interactions in binary mixtures of ethanol in methanol

NASA Astrophysics Data System (ADS)

Maharolkar, Aruna P.; Khirade, P. W.; Murugkar, A. G.

2016-05-01

Present paper deals with study of physicochemical properties like viscosity, density and refractive index for the binary mixtures of ethanol and methanol over the entire concentration range were measured at 298.15 K. The experimental data further used to determine the excess properties viz. excess molar volume, excess viscosity, excess molar refraction. The values of excess properties further fitted with Redlich-Kister (R-K Fit) equation to calculate the binary coefficients and standard deviation. The resulting excess parameters are used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures. Excess parameters indicate structure making factor in the mixture predominates in the system.

Densities, Excess Molar Volumes, Viscosities, and Refractive Indices of Binary Mixtures of n-Butyl Acetate with 1-Chloroalkanes (C4-C8) at 298.15 K

NASA Astrophysics Data System (ADS)

Iloukhani, H.; Khanlarzadeh, K.; Rakhshi, M.

2011-03-01

Densities, viscosities, and refractive indices of binary mixtures of n-butyl acetate (1) +1-chlorobutane (2), +1-chloropentane (2), +1-chlorohexane (2), +1-chloroheptane (2), and +1-chlorooctane (2) were measured at 298.15 K for the liquid region and at ambient pressure for the whole composition range. The excess molar volumes V E were calculated from experimental densities. McAllister's three-body interaction, and Hind and Grunberg-Nissan models are used for correlating the viscosity of binary mixtures. The experimental data of binaries are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.

Individual and binary toxicity of anatase and rutile nanoparticles towards Ceriodaphnia dubia.

PubMed

Iswarya, V; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

2016-09-01

Increasing usage of engineered nanoparticles, especially Titanium dioxide (TiO2) in various commercial products has necessitated their toxicity evaluation and risk assessment, especially in the aquatic ecosystem. In the present study, a comprehensive toxicity assessment of anatase and rutile NPs (individual as well as a binary mixture) has been carried out in a freshwater matrix on Ceriodaphnia dubia under different irradiation conditions viz., visible and UV-A. Anatase and rutile NPs produced an LC50 of about 37.04 and 48mg/L, respectively, under visible irradiation. However, lesser LC50 values of about 22.56 (anatase) and 23.76 (rutile) mg/L were noted under UV-A irradiation. A toxic unit (TU) approach was followed to determine the concentrations of binary mixtures of anatase and rutile. The binary mixture resulted in an antagonistic and additive effect under visible and UV-A irradiation, respectively. Among the two different modeling approaches used in the study, Marking-Dawson model was noted to be a more appropriate model than Abbott model for the toxicity evaluation of binary mixtures. The agglomeration of NPs played a significant role in the induction of antagonistic and additive effects by the mixture based on the irradiation applied. TEM and zeta potential analysis confirmed the surface interactions between anatase and rutile NPs in the mixture. Maximum uptake was noticed at 0.25 total TU of the binary mixture under visible irradiation and 1 TU of anatase NPs for UV-A irradiation. Individual NPs showed highest uptake under UV-A than visible irradiation. In contrast, binary mixture showed a difference in the uptake pattern based on the type of irradiation exposed. Copyright © 2016 Elsevier B.V. All rights reserved.

A study of the kinetics and isotherms for Cr(VI) adsorption in a binary mixture of Cr(VI)-Ni(II) using hierarchical porous carbon obtained from pig bone.

PubMed

Li, Chengxian; Huang, Zhe; Huang, Bicheng; Liu, Changfeng; Li, Chengming; Huang, Yaqin

2014-01-01

Cr(VI) adsorption in a binary mixture Cr(VI)-Ni(II) using the hierarchical porous carbon prepared from pig bone (HPC) was investigated. The various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as initial concentration, pH, temperature and contact time were analyzed. The results showed excellent efficiency of Cr(VI) adsorption by HPC. The kinetics and isotherms for Cr(VI) adsorption from a binary mixture Cr(VI)-Ni(II) by HPC were studied. The adsorption equilibrium described by the Langmuir isotherm model is better than that described by the Freundlich isotherm model for the binary mixture in this study. The maximum adsorption capacity was reliably found to be as high as 192.68 mg/g in the binary mixture at pH 2. On fitting the experimental data to both pseudo-first- and second-order equations, the regression analysis of the second-order equation gave a better R² value.

Probing Intermolecular Interactions in Binary Liquid Mixtures Using Femtosecond Laser-Induced Self-Defocusing.

PubMed

Maurya, Sandeep Kumar; Das, Dhiman; Goswami, Debabrata

2016-06-13

Photo-thermal behavior of binary liquid mixtures has been studied by high repetition rate (HRR) Z-scan technique with femtosecond laser pulses. Changes in the peak-valley difference in transmittance (ΔT P-V ) for closed aperture Z-scan experiments are indicative of thermal effects induced by HRR femtosecond laser pulses. We show such indicative results can have a far-reaching impact on molecular properties and intermolecular interactions in binary liquid mixtures. Spectroscopic parameters derived from this experimental technique show that the combined effect of physical and molecular properties of the constituent binary liquids can be related to the components of the binary liquid. © The Author(s) 2016.

Facile Fabrication of Hierarchically Thermoresponsive Binary Polymer Pattern for Controlled Cell Adhesion.

PubMed

Hou, Jianwen; Cui, Lele; Chen, Runhai; Xu, Xiaodong; Chen, Jiayue; Yin, Ligang; Liu, Jingchuan; Shi, Qiang; Yin, Jinghua

2018-03-01

A versatile platform allowing capture and detection of normal and dysfunctional cells on the same patterned surface is important for accessing the cellular mechanism, developing diagnostic assays, and implementing therapy. Here, an original and effective method for fabricating binary polymer brushes pattern is developed for controlled cell adhesion. The binary polymer brushes pattern, composed of poly(N-isopropylacrylamide) (PNIPAAm) and poly[poly(ethylene glycol) methyl ether methacrylate] (POEGMA) chains, is simply obtained via a combination of surface-initiated photopolymerization and surface-activated free radical polymerization. This method is unique in that it does not utilize any protecting groups or procedures of backfilling with immobilized initiator. It is demonstrated that the precise and well-defined binary polymer patterns with high resolution are fabricated using this facile method. PNIPAAm chains capture and release cells by thermoresponsiveness, while POEGMA chains possess high capability to capture dysfunctional cells specifically, inducing a switch of normal red blood cells (RBCs) arrays to hemolytic RBCs arrays on the pattern with temperature. This novel platform composed of binary polymer brush pattern is smart and versatile, which opens up pathways to potential applications as microsensors, biochips, and bioassays. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimising Drug Solubilisation in Amorphous Polymer Dispersions: Rational Selection of Hot-melt Extrusion Processing Parameters.

PubMed

Li, Shu; Tian, Yiwei; Jones, David S; Andrews, Gavin P

2016-02-01

The aim of this article was to construct a T-ϕ phase diagram for a model drug (FD) and amorphous polymer (Eudragit® EPO) and to use this information to understand the impact of how temperature-composition coordinates influenced the final properties of the extrudate. Defining process boundaries and understanding drug solubility in polymeric carriers is of utmost importance and will help in the successful manufacture of new delivery platforms for BCS class II drugs. Physically mixed felodipine (FD)-Eudragit(®) EPO (EPO) binary mixtures with pre-determined weight fractions were analysed using DSC to measure the endset of melting and glass transition temperature. Extrudates of 10 wt% FD-EPO were processed using temperatures (110°C, 126°C, 140°C and 150°C) selected from the temperature-composition (T-ϕ) phase diagrams and processing screw speed of 20, 100 and 200rpm. Extrudates were characterised using powder X-ray diffraction (PXRD), optical, polarised light and Raman microscopy. To ensure formation of a binary amorphous drug dispersion (ADD) at a specific composition, HME processing temperatures should at least be equal to, or exceed, the corresponding temperature value on the liquid-solid curve in a F-H T-ϕ phase diagram. If extruded between the spinodal and liquid-solid curve, the lack of thermodynamic forces to attain complete drug amorphisation may be compensated for through the use of an increased screw speed. Constructing F-H T-ϕ phase diagrams are valuable not only in the understanding drug-polymer miscibility behaviour but also in rationalising the selection of important processing parameters for HME to ensure miscibility of drug and polymer.

Laboratory evaluation of Honeywell polymer vs SBS polymer modified asphalt mixtures.

DOT National Transportation Integrated Search

2013-05-01

The scope of the study is to evaluate the laboratory performance of two asphalt mixtures; : one modified with SBS polymer and the second modified with a polymer from : Honeywell. Both asphalt binder and mixture properties are proposed to be evaluated...

Self-diffusion Coefficient and Structure of Binary n-Alkane Mixtures at the Liquid-Vapor Interfaces.

PubMed

Chilukoti, Hari Krishna; Kikugawa, Gota; Ohara, Taku

2015-10-15

The self-diffusion coefficient and molecular-scale structure of several binary n-alkane liquid mixtures in the liquid-vapor interface regions have been examined using molecular dynamics simulations. It was observed that in hexane-tetracosane mixture hexane molecules are accumulated in the liquid-vapor interface region and the accumulation intensity decreases with increase in a molar fraction of hexane in the examined range. Molecular alignment and configuration in the interface region of the liquid mixture change with a molar fraction of hexane. The self-diffusion coefficient in the direction parallel to the interface of both tetracosane and hexane in their binary mixture increases in the interface region. It was found that the self-diffusion coefficient of both tetracosane and hexane in their binary mixture is considerably higher in the vapor side of the interface region as the molar fraction of hexane goes lower, which is mostly due to the increase in local free volume caused by the local structure of the liquid in the interface region.

Reducing Dangerous Effects of Unsymmetrical Dimethyl Hydrazine as a Liquid Propellant by Addition of Hydroxyethylhydrazine, Part II, Performance with Several Oxidizers

NASA Astrophysics Data System (ADS)

Keshavarz, Mohammad Hossein; Ramadan, Alireza; Mousaviazar, Ali; Zali, Abbas; Shokrollahi, Arash

2011-07-01

This work continues the study of suitable binary liquid mixtures of unsymmetrical dimethylhydrazine (UDMH) and hydroxyethylhydrazine (HEH) to reduce the harmful effects of pure UDMH. The synthesized HEH was mixed with UDMH up to 40 wt% of HEH to study the performance and properties of binary liquid mixtures of UDMH/HEH. The existence of strong hydrogen bonding between HEH and UDMH provides low-volatile mixtures of these hydrazine derivatives. The addition of HEH significantly reduces the vapor pressure of UDMH, thus reducing the known UDMH health risk to inhalation exposure. Specific impulse was used to study performance of binary mixture UDMH/HEH with respect to pure UDMH. A binary mixture of UDMH/HEH reacts spontaneously in contact with nitrogen tetroxide, red fuming nitric acid (RFNA), and inhibited red fuming nitric acid (IRFNA).

The ‘ideal selectivity’ vs ‘true selectivity’ for permeation of gas mixture in nanoporous membranes

NASA Astrophysics Data System (ADS)

He, Zhou; Wang, Kean

2018-03-01

In this study, we proposed and validated a novel and non-destructive experimental technology for measuring the permeation of binary gas mixture in nanoporous membranes. The traditional time lag rig was modified to examine the permeation characteristics of each gas component as well as that of the binary gas mixtures. The difference in boiling points of each species were explored. Binary gas mixtures of CO2/He were permeated through the nanoporous carbon molecular sieve membrane (CMSM). The results showed that, due to the strong interaction among different molecules and with the porous network of the membrane, the measured perm-selectivity or ‘true selectivity’ of a binary mixture can significantly deviate from the ‘ideal selectivity’ calculated form the permeation flux of each pure species, and this deviation is a complicated function of the molecular properties and operation conditions.

Using Delaunay triangulation and Voronoi tessellation to predict the toxicities of binary mixtures containing hormetic compound

NASA Astrophysics Data System (ADS)

Qu, Rui; Liu, Shu-Shen; Zheng, Qiao-Feng; Li, Tong

2017-03-01

Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of various types of binary mixtures, an interpolation method based on the Delaunay triangulation (DT) and Voronoi tessellation (VT) as well as the training set of direct equipartition ray design (EquRay) mixtures, simply IDVequ. At first, the EquRay was employed to design the basic concentration compositions of five binary mixture rays. The toxic effects of single components and mixture rays at different times and various concentrations were determined by the time-dependent microplate toxicity analysis. Secondly, the concentration-toxicity data of the pure components and various mixture rays were acted as a training set. The DT triangles and VT polygons were constructed by various vertices of concentrations in the training set. The toxicities of unknown mixtures were predicted by the linear interpolation and natural neighbor interpolation of vertices. The IDVequ successfully predicted the toxicities of various types of binary mixtures.

Thermodynamics and structural transition of binary atomic Bose-Fermi mixtures in box or harmonic potentials: A path-integral study

NASA Astrophysics Data System (ADS)

Kim, Tom; Chien, Chih-Chun

2018-03-01

Experimental realizations of a variety of atomic binary Bose-Fermi mixtures have brought opportunities for studying composite quantum systems with different spin statistics. The binary atomic mixtures can exhibit a structural transition from a mixture into phase separation as the boson-fermion interaction increases. By using a path-integral formalism to evaluate the grand partition function and the thermodynamic grand potential, we obtain the effective potential of binary Bose-Fermi mixtures. Thermodynamic quantities in a broad range of temperatures and interactions are also derived. The structural transition can be identified as a loop of the effective potential curve, and the volume fraction of phase separation can be determined by the lever rule. For 6Li-7Li and 6Li-41K mixtures, we present the phase diagrams of the mixtures in a box potential at zero and finite temperatures. Due to the flexible densities of atomic gases, the construction of phase separation is more complicated when compared to conventional liquid or solid mixtures where the individual densities are fixed. For harmonically trapped mixtures, we use the local density approximation to map out the finite-temperature density profiles and present typical trap structures, including the mixture, partially separated phases, and fully separated phases.

Using Delaunay triangulation and Voronoi tessellation to predict the toxicities of binary mixtures containing hormetic compound

PubMed Central

Qu, Rui; Liu, Shu-Shen; Zheng, Qiao-Feng; Li, Tong

2017-01-01

Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of various types of binary mixtures, an interpolation method based on the Delaunay triangulation (DT) and Voronoi tessellation (VT) as well as the training set of direct equipartition ray design (EquRay) mixtures, simply IDVequ. At first, the EquRay was employed to design the basic concentration compositions of five binary mixture rays. The toxic effects of single components and mixture rays at different times and various concentrations were determined by the time-dependent microplate toxicity analysis. Secondly, the concentration-toxicity data of the pure components and various mixture rays were acted as a training set. The DT triangles and VT polygons were constructed by various vertices of concentrations in the training set. The toxicities of unknown mixtures were predicted by the linear interpolation and natural neighbor interpolation of vertices. The IDVequ successfully predicted the toxicities of various types of binary mixtures. PMID:28287626

Process for forming shaped group III-V semiconductor nanocrystals, and product formed using process

DOEpatents

Alivisatos, A. Paul; Peng, Xiaogang; Manna, Liberato

2001-01-01

A process for the formation of shaped Group III-V semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

Process for forming shaped group II-VI semiconductor nanocrystals, and product formed using process

DOEpatents

Alivisatos, A. Paul; Peng, Xiaogang; Manna, Liberato

2001-01-01

A process for the formation of shaped Group II-VI semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

Generation of two-dimensional binary mixtures in complex plasmas

NASA Astrophysics Data System (ADS)

Wieben, Frank; Block, Dietmar

2016-10-01

Complex plasmas are an excellent model system for strong coupling phenomena. Under certain conditions the dust particles immersed into the plasma form crystals which can be analyzed in terms of structure and dynamics. Previous experiments focussed mostly on monodisperse particle systems whereas dusty plasmas in nature and technology are polydisperse. Thus, a first and important step towards experiments in polydisperse systems are binary mixtures. Recent experiments on binary mixtures under microgravity conditions observed a phase separation of particle species with different radii even for small size disparities. This contradicts several numerical studies of 2D binary mixtures. Therefore, dedicated experiments are required to gain more insight into the physics of polydisperse systems. In this contribution first ground based experiments on two-dimensional binary mixtures are presented. Particular attention is paid to the requirements for the generation of such systems which involve the consideration of the temporal evolution of the particle properties. Furthermore, the structure of these two-component crystals is analyzed and compared to simulations. This work was supported by the Deutsche Forschungsgemeinschaft DFG in the framework of the SFB TR24 Greifswald Kiel, Project A3b.

Assessment of combined antiandrogenic effects of binary parabens mixtures in a yeast-based reporter assay.

PubMed

Ma, Dehua; Chen, Lujun; Zhu, Xiaobiao; Li, Feifei; Liu, Cong; Liu, Rui

2014-05-01

To date, toxicological studies of endocrine disrupting chemicals (EDCs) have typically focused on single chemical exposures and associated effects. However, exposure to EDCs mixtures in the environment is common. Antiandrogens represent a group of EDCs, which draw increasing attention due to their resultant demasculinization and sexual disruption of aquatic organisms. Although there are a number of in vivo and in vitro studies investigating the combined effects of antiandrogen mixtures, these studies are mainly on selected model compounds such as flutamide, procymidone, and vinclozolin. The aim of the present study is to investigate the combined antiandrogenic effects of parabens, which are widely used antiandrogens in industrial and domestic commodities. A yeast-based human androgen receptor (hAR) assay (YAS) was applied to assess the antiandrogenic activities of n-propylparaben (nPrP), iso-propylparaben (iPrP), methylparaben (MeP), and 4-n-pentylphenol (PeP), as well as the binary mixtures of nPrP with each of the other three antiandrogens. All of the four compounds could exhibit antiandrogenic activity via the hAR. A linear interaction model was applied to quantitatively analyze the interaction between nPrP and each of the other three antiandrogens. The isoboles method was modified to show the variation of combined effects as the concentrations of mixed antiandrogens were changed. Graphs were constructed to show isoeffective curves of three binary mixtures based on the fitted linear interaction model and to evaluate the interaction of the mixed antiandrogens (synergism or antagonism). The combined effect of equimolar combinations of the three mixtures was also considered with the nonlinear isoboles method. The main effect parameters and interaction effect parameters in the linear interaction models of the three mixtures were different from zero. The results showed that any two antiandrogens in their binary mixtures tended to exert equal antiandrogenic activity in the linear concentration ranges. The antiandrogenicity of the binary mixture and the concentration of nPrP were fitted to a sigmoidal model if the concentrations of the other antiandrogens (iPrP, MeP, and PeP) in the mixture were lower than the AR saturation concentrations. Some concave isoboles above the additivity line appeared in all the three mixtures. There were some synergistic effects of the binary mixture of nPrP and MeP at low concentrations in the linear concentration ranges. Interesting, when the antiandrogens concentrations approached the saturation, the interaction between chemicals were antagonistic for all the three mixtures tested. When the toxicity of the three mixtures was assessed using nonlinear isoboles, only antagonism was observed for equimolar combinations of nPrP and iPrP as the concentrations were increased from the no-observed-effect-concentration (NOEC) to effective concentration of 80%. In addition, the interactions were changed from synergistic to antagonistic as effective concentrations were increased in the equimolar combinations of nPrP and MeP, as well as nPrP and PeP. The combined effects of three binary antiandrogens mixtures in the linear ranges were successfully evaluated by curve fitting and isoboles. The combined effects of specific binary mixtures varied depending on the concentrations of the chemicals in the mixtures. At low concentrations in the linear concentration ranges, there was synergistic interaction existing in the binary mixture of nPrP and MeP. The interaction tended to be antagonistic as the antiandrogens approached saturation concentrations in mixtures of nPrP with each of the other three antiandrogens. The synergistic interaction was also found in the equimolar combinations of nPrP and MeP, as well as nPrP and PeP, at low concentrations with another method of nonlinear isoboles. The mixture activities of binary antiandrogens had a tendency towards antagonism at high concentrations and synergism at low concentrations.

Forage production of grass-legume binary mixtures on Intermountain Western USA irrigated pastures

USDA-ARS?s Scientific Manuscript database

A well-managed irrigated pasture is optimized for forage production with the use of N fertilizer which incurs extra expense. The objective was to determine which binary grass-legume mixture and mixture planting ratio of tall fescue (Festuca arundinacea Schreb.) (TF), meadow brome (Bromus bieberstei...

Relaxation dynamics in a binary hard-ellipse liquid.

PubMed

Xu, Wen-Sheng; Sun, Zhao-Yan; An, Li-Jia

2015-01-21

Structural relaxation in binary hard spherical particles has been shown recently to exhibit a wealth of remarkable features when size disparity or mixture composition is varied. In this paper, we test whether or not similar dynamical phenomena occur in glassy systems composed of binary hard ellipses. We demonstrate via event-driven molecular dynamics simulation that a binary hard-ellipse mixture with an aspect ratio of two and moderate size disparity displays characteristic glassy dynamics upon increasing density in both the translational and the rotational degrees of freedom. The rotational glass transition density is found to be close to the translational one for the binary mixtures investigated. More importantly, we assess the influence of size disparity and mixture composition on the relaxation dynamics. We find that an increase of size disparity leads, both translationally and rotationally, to a speed up of the long-time dynamics in the supercooled regime so that both the translational and the rotational glass transition shift to higher densities. By increasing the number concentration of the small particles, the time evolution of both translational and rotational relaxation dynamics at high densities displays two qualitatively different scenarios, i.e., both the initial and the final part of the structural relaxation slow down for small size disparity, while the short-time dynamics still slows down but the final decay speeds up in the binary mixture with large size disparity. These findings are reminiscent of those observed in binary hard spherical particles. Therefore, our results suggest a universal mechanism for the influence of size disparity and mixture composition on the structural relaxation in both isotropic and anisotropic particle systems.

Research on odor interaction between aldehyde compounds via a partial differential equation (PDE) model.

PubMed

Yan, Luchun; Liu, Jiemin; Qu, Chen; Gu, Xingye; Zhao, Xia

2015-01-28

In order to explore the odor interaction of binary odor mixtures, a series of odor intensity evaluation tests were performed using both individual components and binary mixtures of aldehydes. Based on the linear relation between the logarithm of odor activity value and odor intensity of individual substances, the relationship between concentrations of individual constituents and their joint odor intensity was investigated by employing a partial differential equation (PDE) model. The obtained results showed that the binary odor interaction was mainly influenced by the mixing ratio of two constituents, but not the concentration level of an odor sample. Besides, an extended PDE model was also proposed on the basis of the above experiments. Through a series of odor intensity matching tests for several different binary odor mixtures, the extended PDE model was proved effective at odor intensity prediction. Furthermore, odorants of the same chemical group and similar odor type exhibited similar characteristics in the binary odor interaction. The overall results suggested that the PDE model is a more interpretable way of demonstrating the odor interactions of binary odor mixtures.

Intermolecular forces in acetonitrile + ethanol binary liquid mixtures

NASA Astrophysics Data System (ADS)

Elangovan, A.; Shanmugam, R.; Arivazhagan, G.; Mahendraprabu, A.; Karthick, N. K.

2015-10-01

FTIR spectral measurements have been carried out on the binary mixtures of acetonitrile with ethanol at 1:0 (acetonitrile:ethanol), 1:1, 1:2, 1:3 and 0:1 at room temperature. DFT and isosurface calculations have been performed. The acetonitrile + ethanol binary mixtures consist of 1:1, 1:2, 1:3 and 1:4 complexes formed through both the red and blue shifting H-bonds. Inter as well as intra molecular forces are found to exist in 1:3 and 1:4 complexes.

Interfacial free energy governs single polystyrene chain collapse in water and aqueous solutions.

PubMed

Li, Isaac T S; Walker, Gilbert C

2010-05-12

The hydrophobic interaction is significantly responsible for driving protein folding and self-assembly. To understand it, the thermodynamics, the role of water structure, the dewetting process surrounding hydrophobes, and related aspects have undergone extensive investigations. Here, we examine the hypothesis that polymer-solvent interfacial free energy is adequate to describe the energetics of the collapse of a hydrophobic homopolymer chain at fixed temperature, which serves as a much simplified model for studying the hydrophobic collapse of a protein. This implies that changes in polymer-solvent interfacial free energy should be directly proportional to the force to extend a collapsed polymer into a bad solvent. To test this hypothesis, we undertook single-molecule force spectroscopy on a collapsed, single, polystyrene chain in water-ethanol and water-salt mixtures where we measured the monomer solvation free energy from an ensemble average conformations. Different proportions within the binary mixture were used to create solvents with different interfacial free energies with polystyrene. In these mixed solvents, we observed a linear correlation between the interfacial free energy and the force required to extend the chain into solution, which is a direct measure of the solvation free energy per monomer on a single chain at room temperature. A simple analytical model compares favorably with the experimental results. This knowledge supports a common assumption that explicit water solvent may not be necessary for cases whose primary concerns are hydrophobic interactions and hydrophobic hydration.

Spectroscopic and DFT study of solvent effects on the electronic absorption spectra of sulfamethoxazole in neat and binary solvent mixtures

NASA Astrophysics Data System (ADS)

Almandoz, M. C.; Sancho, M. I.; Blanco, S. E.

2014-01-01

The solvatochromic behavior of sulfamethoxazole (SMX) was investigated using UV-vis spectroscopy and DFT methods in neat and binary solvent mixtures. The spectral shifts of this solute were correlated with the Kamlet and Taft parameters (α, β and π*). Multiple lineal regression analysis indicates that both specific hydrogen-bond interaction and non specific dipolar interaction play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra using TD-DFT methods were in good agreement with the experimental ones. Binary mixtures consist of cyclohexane (Cy)-ethanol (EtOH), acetonitrile (ACN)-dimethylsulfoxide (DMSO), ACN-dimethylformamide (DMF), and aqueous mixtures containing as co-solvents DMSO, ACN, EtOH and MeOH. Index of preferential solvation was calculated as a function of solvent composition and non-ideal characteristics are observed in all binary mixtures. In ACN-DMSO and ACN-DMF mixtures, the results show that the solvents with higher polarity and hydrogen bond donor ability interact preferentially with the solute. In binary mixtures containing water, the SMX molecules are solvated by the organic co-solvent (DMSO or EtOH) over the whole composition range. Synergistic effect is observed in the case of ACN-H2O and MeOH-H2O, indicating that at certain concentrations solvents interact to form association complexes, which should be more polar than the individual solvents of the mixture.

Development of a binary carrier system consisting polyethylene glycol 4000 - ethyl cellulose for ibuprofen solid dispersion

PubMed Central

Alagdar, Gada Sulaiman A.; Oo, May Kyaw; Sengupta, Pinaki; Mandal, Uttam Kumar; Jaffri, Julian Md.; Chatterjee, Bappaditya

2017-01-01

Background and Objective: One of the established strategies to improve solubility and dissolution rate of poorly water-soluble drugs is solid dispersion (SD). Polyethylene glycol (PEG) is used as common carrier despite its stability problem which may be overcome by the addition of hydrophobic polymer. The present research aimed to develop an SD formulation with ibuprofen, a poor water-soluble BCS Class II drug as active pharmaceutical ingredient (API) and PEG 4000-ethyl cellulose (EC) as binary carrier. Methods: Melt mixing SD method was employed using a ratio of API: binary carrier (1:3.5 w/w) (SDPE). Another SD was prepared using only PEG (SDP) as a carrier for comparative study. The developed formulation was evaluated using optical microscopy, scanning electron microscopy (SEM), determination of moisture content, differential scanning calorimetry (DSC), in vitro dissolution test, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and flow properties. Results: SEM and DSC indicated the conversion of crystalline ibuprofen to fine partly amorphous solid dispersion, which was responsible for the increase in dissolution rate of SD than a physical mixture. The release characteristics within 1 h from the higher to the lower value were the SDPE> SDP> physical mixture. Flow property evaluation using the angle of repose showed no difference between SD and PM. However, by Carr index and Hausner ratio, the flow properties of SDPE was excellent. Conclusion: The SD formulation with the PEG 4000-EC carrier can be effective to enhance in vitro dissolution of ibuprofen immediate release dosage form. PMID:29184827

Thermodiffusion, molecular diffusion and Soret coefficient of binary and ternary mixtures of n-hexane, n-dodecane and toluene.

PubMed

Alonso de Mezquia, David; Wang, Zilin; Lapeira, Estela; Klein, Michael; Wiegand, Simone; Mounir Bou-Ali, M

2014-11-01

In this study, the thermodiffusion, molecular diffusion, and Soret coefficients of 12 binary mixtures composed of toluene, n-hexane and n-dodecane in the whole range of concentrations at atmospheric pressure and temperatures of 298.15 K and 308.15 K have been determined. The experimental measurements have been carried out using the Thermogravitational Column, the Sliding Symmetric Tubes and the Thermal Diffusion Forced Rayleigh Scattering techniques. The results obtained using the different techniques show a maximum deviation of 9% for the thermodiffusion coefficient, 8% for the molecular diffusion coefficient and 2% for the Soret coefficient. For the first time we report a decrease of the thermodiffusion coefficient with increasing ratio of the thermal expansion coefficient and viscosity for a binary mixture of an organic ring compound with a short n-alkane. This observation is discussed in terms of interactions between the different components. Additionally, the thermogravitational technique has been used to measure the thermodiffusion coefficients of four ternary mixtures consisting of toluene, n-hexane and n-dodecane at 298.15 K. In order to complete the study, the values obtained for the molecular diffusion coefficient in binary mixtures, and the thermodiffusion coefficient of binary and ternary mixtures have been compared with recently derived correlations.

Viscosity of nonelectrolyte liquid mixtures. III Binary mixtures of methyl methacrylate with hydrocarbons, haloalkanes, and alkylamines

NASA Astrophysics Data System (ADS)

Oswal, S. L.; Patel, B. M.; Shah, H. R.; Oswal, P.

1994-07-01

Measurements of the viscosity η and the density ϱ are reported for 14 binary mixtures of methyl methacrylate (MMA) with hydrocarbons, haloalkanes, and alkylamines at 303.15 K. The viscosity data have been correlated with equations of Grunberg and Nissan, of McAllister, and of Auslaender. Furthermore, excess viscosity Δ In η and excess Gibbs energy of activation ΔG* E of viscous flow have been calculated and have been used to predict molecular interactions occurring in present binary mixtures. The results show the existence of specific interactions in MMA + aromatic hydrocarbons, MMA + haloalkanes, and MMA + primary amines.

Headspace quantification of pure and aqueous solutions of binary mixtures of key volatile organic compounds in Swiss cheeses using selected ion flow tube mass spectrometry.

PubMed

Castada, Hardy Z; Wick, Cheryl; Harper, W James; Barringer, Sheryl

2015-01-15

Twelve volatile organic compounds (VOCs) have recently been identified as key compounds in Swiss cheese with split defects. It is important to know how these VOCs interact in binary mixtures and if their behavior changes with concentration in binary mixtures. Selected ion flow tube mass spectrometry (SIFT-MS) was used for the headspace analysis of VOCs commonly found in Swiss cheeses. Headspace (H/S) sampling and quantification checks using SIFT-MS and further linear regression analyses were carried out on twelve selected aqueous solutions of VOCs. Five binary mixtures of standard solutions of VOCs were also prepared and the H/S profile of each mixture was analyzed. A very good fit of linearity for the twelve VOCs (95% confidence level) confirms direct proportionality between the H/S and the aqueous concentration of the standard solutions. Henry's Law coefficients were calculated with a high degree of confidence. SIFT-MS analysis of five binary mixtures showed that the more polar compounds reduced the H/S concentration of the less polar compounds, while the addition of a less polar compound increased the H/S concentration of the more polar compound. In the binary experiment, it was shown that the behavior of a compound in the headspace can be significantly affected by the presence of another compound. Thus, the matrix effect plays a significant role in the behavior of molecules in a mixed solution. Copyright © 2014 John Wiley & Sons, Ltd.

Determination of solvents permeating through chemical protective clothing with a microsensor array.

PubMed

Park, J; Zellers, E T

2000-08-01

The performance of a novel prototype instrument in determining solvents and solvent mixtures permeating through samples of chemical protective clothing (CPC) materials was evaluated. The instrument contains a mini-preconcentrator and an array of three polymer-coated surface-acoustic-wave (SAW) microsensors whose collective response patterns are used to discriminate among multiple permeants. Permeation tests were performed with a 2.54 cm diameter test cell in an open-loop configuration on samples of common glove materials challenged with four individual solvents, three binary mixtures, and two ternary mixtures. Breakthrough times, defined as the times required for the permeation rate to reach a value of 1 microg cm(-2) min(-1), determined by the instrument were within 3 min of those determined in parallel by manual sampling and gas chromatographic analysis. Permeating solvents were recognized (identified) from their response patterns in 59 out of 64 measurements (92%) and their vapor concentrations were quantified to an accuracy of +/- 31% (typically +/- 10%). These results demonstrate the potential for such instrumentation to provide semi-automated field or bench-top screening of CPC permeation resistance.

The Hb A variant (beta73 Asp-->Leu) disrupts Hb S polymerization by a novel mechanism.

PubMed

Adachi, Kazuhiko; Ding, Min; Surrey, Saul; Rotter, Maria; Aprelev, Alexey; Zakharov, Mikhail; Weng, Weijun; Ferrone, Frank A

2006-09-22

Polymerization of a 1:1 mixture of hemoglobin S (Hb S) and the artificial mutant HbAbeta73Leu produces a dramatic morphological change in the polymer domains in 1.0 M phosphate buffer that are a characteristic feature of polymer formation. Instead of feathery domains with quasi 2-fold symmetry that characterize polymerization of Hb S and all previously known mixtures such as Hb A/S and Hb F/S mixtures, these domains are compact structures of quasi-spherical symmetry. Solubility of Hb S/Abeta73Leu mixtures was similar to that of Hb S/F mixtures. Kinetics of polymerization indicated that homogeneous nucleation rates of Hb S/Abeta73Leu mixtures were the same as those of Hb S/F mixtures, while exponential polymer growth (B) of Hb S/Abeta73Leu mixtures were about three times slower than those of Hb S/F mixtures. Differential interference contrast (DIC) image analysis also showed that fibers in the mixture appear to elongate between three and five times more slowly than in equivalent Hb S/F mixtures by direct measurements of exponential growth of mass of polymer in a domain. We propose that these results of Hb S/Abeta73Leu mixtures arise from a non-productive binding of the hybrid species of this mixture to the end of the growing polymer. This "cap" prohibits growth of polymers, but by nature is temporary, so that the net effect is a lowered growth rate of polymers. Such a cap is consistent with known features of the structure of the Hb S polymer. Domains would be more spherulitic because slower growth provides more opportunity for fiber bending to spread domains from their initial 2-fold symmetry. Moreover, since monomer depletion proceeds more slowly in this mixture, more homogeneous nucleation events occur, and the resulting gel has a far more granular character than normally seen in mixtures of non-polymerizing hemoglobins with Hb S. This mixture is likely to be less stiff than polymerized mixtures of other hybrids such as Hb S with HbF, potentially providing a novel approach to therapy.

Separation of Pr and Nd from La in chloride solution by extraction with a mixture of Cyanex 272 and Alamine 336

NASA Astrophysics Data System (ADS)

Liu, Yang; Jeon, Ho Seok; Lee, Man Seung

2015-09-01

The possibility of separation of Pr and Nd from La in a chloride leaching solution of monazite sand has been investigated by using a binary mixture of Cyanex 272 (bis(2,4,4-trimethylpentyl) phosphinic acid) and Alamine 336 (tri-octyl/decyl amine). The binary mixture showed synergism on the extraction of the three metals and led to an increase in the separation factor between Pr/Nd and La compared to Cyanex 272 alone. Although the addition of chloride ion into aqueous increased the extraction of the metals, this addition had negative effect on the separation of Nd/Pr and La. McCabe-Thiele diagrams for the extraction of Pr and Nd with the binary mixture were constructed. Stripping of metals from the loaded organic phase was achieved with 0.7 M HCl. The difference in the solvent extraction of the rare earth elements from chloride solution between the binary mixture and saponified extractants was also discussed.

Phase behavior and structure of stable complexes between a long polyanion and a branched polycation

NASA Astrophysics Data System (ADS)

Mengarelli, Valentina; Zeghal, Mehdi; Auvray, Loïc; Clemens, Daniel

2011-08-01

The association between oppositely charged branched polyethylenimine (BPEI) and polymethacrylic acid (PMA) in the dilute regime is investigated using turbidimetric titration and electrophoretic mobility measurements. The complexation is controlled by tuning continuously the pH-sensitive charge of the polyacid in acidic solution. The formation of soluble and stable positively charged complexes is a cooperative process characterized by the existence of two regimes of weak and strong complexation. In the regime of weak complexation, a long PMA chain overcharged by several BPEI molecules forms a binary complex. As the charge of the polyacid increases, these binary complexes condense at a well defined charge ratio of the mixture to form large positively charged aggregates. The overcharging and the existence of two regimes of complexation are analyzed in the light of recent theories. The structure of the polyelectrolytes is investigated at higher polymer concentration by small angle neutron scattering. Binary complexes of finite size present an open structure where the polyacid chains connecting a small number of BPEI molecules have shrunk slightly. In the condensed complexes, BPEI molecules, wrapped by polyacid chains, form networks of stretched necklaces.

Unravelling the Composition Dependent Anomalies of Pair Hydrophobicity in Water-Ethanol Binary Mixtures.

PubMed

Halder, Ritaban; Jana, Biman

2018-06-05

Aqueous binary mixtures have received immense attention in recent years because of their extensive application in several biological and industrial processes. Water-ethanol binary mixture serves as a unique system because it exhibits composition dependent alteration of dynamic and thermodynamic properties. Our present work demonstrates how different compositions of water-ethanol binary mixtures affect the pair hydrophobicity of different hydrophobes. Pair hydrophobicity is measured by the depth of the first minimum (contact minima) of potential of mean force (PMF) profile between two hydrophobes. The pair hydrophobicity is found to be increased with addition of ethanol to water up to mole fraction of 0.10 and decreased with further addition of ethanol. This observation is shown to be true for three different pairs of hydrophobes. Decomposition of PMF into enthalpic and entropic contribution indicates a switch from entropic to enthalpic stabilization of the contact minimum upon addition of ethanol to water. The gain in mixing enthalpy of the binary solvent system upon association of two hydrophobes is found to be the determining factor for the stabilization of contact minimum. Several static/dynamics quantities (average composition fluctuations, diffusion coefficients, fluctuations in total dipole moment, propensity of ethyl-ethyl association, etc) of the ethanol-water binary mixture also show irregularities around xEtOH =0.10-0.15. We have also discovered that the hydrogen bonding pattern of ethanol rather than water reveals a change in trend near the similar composition range. As the anomalous behaviour of the physical/dynamical properties along with the pair hydrophobicity in aqueous binary mixture of amphiphilic solutes is common phenomena, our results may provide a general viewpoint on these aspects.

MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

EPA Science Inventory

Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

Structure and component dynamics in binary mixtures of poly(2-(dimethylamino)ethyl methacrylate) with water and tetrahydrofuran: A diffraction, calorimetric, and dielectric spectroscopy study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goracci, G., E-mail: sckgorag@ehu.es; Arbe, A.; Alegría, A.

2016-04-21

We have combined X-ray diffraction, neutron diffraction with polarization analysis, small angle neutron scattering, differential scanning calorimetry, and broad band dielectric spectroscopy to investigate the structure and dynamics of binary mixtures of poly (2-(dimethylamino)ethyl methacrylate) with either water or tetrahydrofuran (THF) at different concentrations. Aqueous mixtures are characterized by a highly heterogeneous structure where water clusters coexist with an underlying nano-segregation of main chains and side groups of the polymeric matrix. THF molecules are homogeneously distributed among the polymeric nano-domains for concentrations of one THF molecule/monomer or lower. A more heterogeneous situation is found for higher THF amounts, but withoutmore » evidences for solvent clusters. In THF-mixtures, we observe a remarkable reduction of the glass-transition temperature which is enhanced with increasing amount of solvent but seems to reach saturation at high THF concentrations. Adding THF markedly reduces the activation energy of the polymer β-relaxation. The presence of THF molecules seemingly hinders a slow component of this process which is active in the dry state. The aqueous mixtures present a strikingly broad glass-transition feature, revealing a highly heterogeneous behavior in agreement with the structural study. Regarding the solvent dynamics, deep in the glassy state all data can be described by an Arrhenius temperature dependence with a rather similar activation energy. However, the values of the characteristic times are about three orders of magnitude smaller for THF than for water. Water dynamics display a crossover toward increasingly higher apparent activation energies in the region of the onset of the glass transition, supporting its interpretation as a consequence of the freezing of the structural relaxation of the surrounding matrix. The absence of such a crossover (at least in the wide dynamic window here accessed) in THF is attributed to the lack of cooperativity effects in the relaxation of these molecules within the polymeric matrix.« less

Binary Mixtures of Particles with Different Diffusivities Demix.

PubMed

Weber, Simon N; Weber, Christoph A; Frey, Erwin

2016-02-05

The influence of size differences, shape, mass, and persistent motion on phase separation in binary mixtures has been intensively studied. Here we focus on the exclusive role of diffusivity differences in binary mixtures of equal-sized particles. We find an effective attraction between the less diffusive particles, which are essentially caged in the surrounding species with the higher diffusion constant. This effect leads to phase separation for systems above a critical size: A single close-packed cluster made up of the less diffusive species emerges. Experiments for testing our predictions are outlined.

Viscosities of nonelectrolyte liquid mixtures. II. Binary and quaternary systems of some n-alkanes

NASA Astrophysics Data System (ADS)

Wakefield, D. L.; Marsh, K. N.; Zwolinski, B. J.

1988-01-01

This paper is the second in a series of viscosity and density studies on multicomponent mixtures of n-alkanes from 303 to 338 K. Reported here are the results of binary mixtures of n-tetracosane + n-octane as well as quaternary mixtures of n-tetracosane + n-octane + n-decane + n-hexane at 318.16, 328.16, and 338.16 K. Viscosities were determined using a standard U-tube Ostwald viscometer, and densities were determined using a flask-type pycnometer. Empirical relations tested include the Grunberg and Nissan equation and the method of corresponding states. In addition, comparisons were made regarding the behavior of this quaternary system and homologous binary mixtures of n-hexadecane + n-octane and n-tetracosane + n-octane at the same temperatures.

ANALYSES OF THE INTERACTIONS WITHIN BINARY MIXTURES OF CARCINOGENIC PAHS USING MORPHOLOGICAL CELL TRANSFORMATION OF C3H10T1/2CL8 CELLS

EPA Science Inventory

ANALYSES OF THE INTERACTIONS WITHIN BINARY MIXTURES OF CARCINOGENIC PAHS USING MORPHOLOGICAL CELL TRANSFORMATION OF C3HIOT1/2 CL8 CELLS.

Studies of defined mixtures of carcinogenic polycyclic aromatic hydrocarbons (PAH) have identified three major categories of interacti...

Synergistic toxicity and physiological impact of imidacloprid alone and binary mixtures with seven representative pesticides on honey bee (Apis mellifera)

USDA-ARS?s Scientific Manuscript database

Imidacloprid is the most widely used insecticide in the world. In this study, we used spraying methods to simulate field exposures of bees to formulated imidacloprid (Advise® 2FL) alone and binary mixtures with seven pesticides from different classes. Synergistic toxicity was detected from mixtures ...

Site specific solubility improvement using solid dispersions of HPMC-AS/HPC SSL--mixtures.

PubMed

Zecevic, Damir Elmar; Meier, Robin; Daniels, Rolf; Wagner, Karl-Gerhard

2014-07-01

Many upcoming drug candidates are pH-dependent poorly soluble weak bases in the pH range of the gastrointestinal tract. This often leads to a high in vivo variability and bioavailability issues. Aiming to overcome these limitations, the design of solid dispersions for site specific dissolution improvement or maintenance of a potent supersaturation over the entire gastro-intestinal pH-range, is proposed to assure a reliable drug therapy. Solid dispersions containing different ratios of Dipyridamole (DPD) or Griseofulvin (GRI) and the enteric polymer hydroxypropylmethylcellulose-acetate succinate (HPMC-AS) and the water soluble low-viscosity hydroxypropylcellulose (HPC-SSL) were prepared by hot melt extrusion (HME). The solid dispersions were evaluated for their solid state, dissolution characteristics applying a three pH-step dissolution method following an acidic to neutral pH transition and stability. The use of HPMC-AS in binary mixtures with DPD and GRI facilitated increased solubility and supersaturation at pH-controlled release of the preserved amorphous state of the dispersed drug, which even inverted the pH-dependent solubility profile of the weakly basic model drug (Dipyridamole). I.e. a potent site specific delivery system was created. With ternary solid dispersions of API, HPMC-AS and HPC-SSL, tailored release profiles with superior supersaturation over the applied pH-range could be obtained. At the same time, binary and ternary mixtures showed favorable stability properties at a temperature difference between glass transition temperature and the applied storage temperature of down to 16°C. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical composition and binary mixture of human urinary stones using FT-Raman spectroscopy method.

PubMed

Selvaraju, R; Raja, A; Thiruppathi, G

2013-10-01

In the present study the human urinary stones were observed in their different chemical compositions of calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate, struvite (magnesium ammonium phosphate), uric acid, cystine, oxammite (ammonium oxalate monohydrate), natroxalate (sodium oxalate), glushinkite (magnesium oxalate dihydrate) and moolooite (copper oxalate) were analyzed using Fourier Transform-Raman (FT-Raman) spectroscopy. For the quantitative analysis, various human urinary stone samples are used for ratios calculation of binary mixtures compositions such as COM/COD, HAP/COD, HAP/COD, Uric acid/COM, uric acid/COD and uric acid/HAP. The calibration curve is used for further analysis of binary mixture of human urinary stones. For the binary mixture calculation the various intensities bands at 1462 cm(-1) (I(COM)), 1473 cm(-1) (I(COD)), 961 cm(-1) (I(HAP)) and 1282 cm(-1) (I(UA)) were used. Copyright © 2013 Elsevier B.V. All rights reserved.

Monte Carlo study of four dimensional binary hard hypersphere mixtures

NASA Astrophysics Data System (ADS)

Bishop, Marvin; Whitlock, Paula A.

2012-01-01

A multithreaded Monte Carlo code was used to study the properties of binary mixtures of hard hyperspheres in four dimensions. The ratios of the diameters of the hyperspheres examined were 0.4, 0.5, 0.6, and 0.8. Many total densities of the binary mixtures were investigated. The pair correlation functions and the equations of state were determined and compared with other simulation results and theoretical predictions. At lower diameter ratios the pair correlation functions of the mixture agree with the pair correlation function of a one component fluid at an appropriately scaled density. The theoretical results for the equation of state compare well to the Monte Carlo calculations for all but the highest densities studied.

The scent of mixtures: rules of odour processing in ants

PubMed Central

Perez, Margot; Giurfa, Martin; d'Ettorre, Patrizia

2015-01-01

Natural odours are complex blends of numerous components. Understanding how animals perceive odour mixtures is central to multiple disciplines. Here we focused on carpenter ants, which rely on odours in various behavioural contexts. We studied overshadowing, a phenomenon that occurs when animals having learnt a binary mixture respond less to one component than to the other, and less than when this component was learnt alone. Ants were trained individually with alcohols and aldehydes varying in carbon-chain length, either as single odours or binary mixtures. They were then tested with the mixture and the components. Overshadowing resulted from the interaction between chain length and functional group: alcohols overshadowed aldehydes, and longer chain lengths overshadowed shorter ones; yet, combinations of these factors could cancel each other and suppress overshadowing. Our results show how ants treat binary olfactory mixtures and set the basis for predictive analyses of odour perception in insects. PMID:25726692

Polymer-Induced Depletion Interaction and Its Effect on Colloidal Sedimentation in Colloid-Polymer Mixtures

NASA Technical Reports Server (NTRS)

Tong, Penger

1996-01-01

In this paper we focus on the polymer-induced depletion attraction and its effect on colloidal sedimentation in colloid-polymer mixtures. We first report a small angle neutron scattering (SANS) study of the depletion effect in a mixture of hard-sphere-like colloid and non-adsorbing polymer. Then we present results of our recent sedimentation measurements in the same colloid-polymer mixture. A key parameter in controlling the sedimentation of heavy colloidal particles is the interparticle potential U(tau), which is the work required to bring two colloidal particles from infinity to a distance tau under a give solvent condition. This potential is known to affect the average settling velocity of the particles and experimentally one needs to have a way to continuously vary U(tau) in order to test the theory. The interaction potential U(tau) can be altered by adding polymer molecules into the colloidal suspension. In a mixture of colloid and non-adsorbing polymer, the potential U(tau) can develop an attractive well because of the depletion effect, in that the polymer chains are expelled from the region between two colloidal particles when their surface separation becomes smaller than the size of the polymer chains. The exclusion of polymer molecules from the space between the colloidal particles leads to an unbalanced osmotic pressure difference pushing the colloidal particles together, which results in an effective attraction between the two colloidal particles. The polymer-induced depletion attraction controls the phase stability of many colloid-polymer mixtures, which are directly of interest to industry.

Comparison studies on the percolation thresholds of binary mixture tablets containing excipients of plastic/brittle and plastic/plastic deformation properties.

PubMed

Amin, Mohd C I; Fell, John T

2004-01-01

Percolation theory has been used with great interest in understanding the design and characterization of dosage forms. In this study, work has been carried out to investigate the behavior of binary mixture tablets containing excipients of similar and different deformation properties. The binary mixture tablets were prepared by direct compression using lactose, polyvinyl chloride (PVC), Eudragit RS 100, and microcrystalline cellulose (MCC). The application of percolation theory on the relationships between compactibility, Pmax, or compression susceptibility (compressibility), gamma, and mixture compositions reveals the presence of percolation thresholds even for mixtures of similar deformation properties. The results showed that all mixture compositions exhibited at least one discreet change in the slope, which was referred to as the percolation threshold. The PVC/Eudragit RS100 mixture compositions showed significant percolation threshold at 80% (w/w) PVC loading. Two percolation thresholds were observed from a series of binary mixtures containing similar plastic deformation materials (PVC/MCC). The percolation thresholds were determined at 20% (w/w) and 80% (w/w) PVC loading. These are areas where one of the components percolates throughout the system and the properties of the tablets are expected to experience a sudden change. Experimental results, however, showed that total disruption of the tablet physical properties at the specified percolation thresholds can be observed for PVC/lactose mixtures at 20-30% (w/w) loading while only minor changes in the tablets' strength for PVC/MCC or PVC/Eudragit RS 100 mixtures were observed.

Intrinsic viscosity of binary gum mixtures with xanthan gum and guar gum: Effect of NaCl, sucrose, and pH.

PubMed

Bak, J H; Yoo, B

2018-05-01

The intrinsic viscosity ([η]) values of binary gum mixtures with xanthan gum (XG) and guar gum (GG) mixed with NaCl and sucrose at different concentrations as well as in the presence of different pH levels were examined in dilute solution as a function of XG/GG mixing ratio (100/0, 75/25, 50/50, and 0/100). Experimental values of concentration (C) and relative viscosity (η rel ) or specific viscosity (η sp ) of gums in dilute solution were fitted to five models to determine [η] values of binary gum mixtures including individual gums. A [η] model (η rel =1+[η]C) of Tanglertpaibul and Rao is recommended as the best model to estimate [η] values for the binary gum mixtures with XG and GG as affected by NaCl, sucrose, and pH. Overall, the synergistic interaction of XG-GG mixtures in the presence of NaCl and sucrose showed a greatly positive variation between measured and calculated values of [η]. In contrast, the binary gum mixtures showed synergy only under an acidic condition (pH3). These results suggest that the NaCl and sucrose addition or acidic condition appears to affect the intermolecular interaction occurred between XG and GG at different gum mixing ratios. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecular Factors Governing the Liquid and Glassy States Recrystallization of Celecoxib in Binary Mixtures with Excipients of Different Molecular Weights.

PubMed

Grzybowska, K; Chmiel, K; Knapik-Kowalczuk, J; Grzybowski, A; Jurkiewicz, K; Paluch, M

2017-04-03

Transformation of poorly water-soluble crystalline pharmaceuticals to the amorphous form is one of the most promising strategies to improve their oral bioavailability. Unfortunately, the amorphous drugs are usually thermodynamically unstable and may quickly return to their crystalline form. A very promising way to enhance the physical stability of amorphous drugs is to prepare amorphous compositions of APIs with certain excipients which can be characterized by significantly different molecular weights, such as polymers, acetate saccharides, and other APIs. By using different experimental techniques (broadband dielectric spectroscopy, differential scanning calorimetry, X-ray diffraction) we compare the effect of adding the large molecular weight polymer-polyvinylpyrrolidone (PVP K30)-and the small molecular weight excipient-octaacetylmaltose (acMAL)-on molecular dynamics as well as the tendency to recrystallization of the amorphous celecoxib (CEL) in the amorphous solid dispersions: CEL-PVP and CEL-acMAL. The physical stability investigations of the binary systems were performed in both the supercooled liquid and glassy states. We found that acMAL is a better inhibitor of recrystallization of amorphous CEL than PVP K30 deep in the glassy state (T < T g ). In contrast, PVP K30 is a better crystallization inhibitor of CEL than acMAL in the supercooled liquid state (at T > T g ). We discuss molecular factors governing the recrystallization of amorphous CEL in examined solid dispersions.

Pharmacokinetic Modeling of JP-8 Jet Fuel Components: II. A Conceptual Framework

DTIC Science & Technology

2003-12-01

example, a single type of (simple) binary interaction between 300 components would require the specification of some 105 interaction coefficients . One...individual substances, via binary mechanisms, is enough to predict the interactions present in the mixture. Secondly, complex mixtures can often be...approximated as pseudo- binary systems, consisting of the compound of interest plus a single interacting complex vehicle with well-defined, composite

Study of drug release and tablet characteristics of silicone adhesive matrix tablets.

PubMed

Tolia, Gaurav; Li, S Kevin

2012-11-01

Matrix tablets of a model drug acetaminophen (APAP) were prepared using a highly compressible low glass transition temperature (T(g)) polymer silicone pressure sensitive adhesive (PSA) at various binary mixtures of silicone PSA/APAP ratios. Matrix tablets of a rigid high T(g) matrix forming polymer ethyl cellulose (EC) were the reference for comparison. Drug release study was carried out using USP Apparatus 1 (basket), and the relationship between the release kinetic parameters of APAP and polymer/APAP ratio was determined to estimate the excipient percolation threshold. The critical points attributed to both silicone PSA and EC tablet percolation thresholds were found to be between 2.5% and 5% w/w. For silicone PSA tablets, satisfactory mechanical properties were obtained above the polymer percolation threshold; no cracking or chipping of the tablet was observed above this threshold. Rigid EC APAP tablets showed low tensile strength and high friability. These results suggest that silicone PSA could eliminate issues related to drug compressibility in the formulation of directly compressed oral controlled release tablets of poorly compressible drug powder such as APAP. No routinely used excipients such as binders, granulating agents, glidants, or lubricants were required for making an acceptable tablet matrix of APAP using silicone PSA. Copyright © 2012 Elsevier B.V. All rights reserved.

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

DOEpatents

Christophorou, Loucas G.; Hunter, Scott R.

1990-01-01

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc.

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

DOEpatents

Christophorou, L.G.; Hunter, S.R.

1990-06-26

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

DOEpatents

Christophorou, L.G.; Hunter, S.R.

1988-06-28

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

The effect of water on thermal stresses in polymer composites

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

1994-01-01

The fundamentals of the thermodynamic theory of mixtures and continuum thermochemistry are reviewed for a mixture of condensed water and polymer. A specific mixture which is mechanically elastic with temperature and water concentration gradients present is considered. An expression for the partial pressure of water in the mixture is obtained based on certain assumptions regarding the thermodynamic state of the water in the mixture. Along with a simple diffusion equation, this partial pressure expression may be used to simulate the thermostructural behavior of polymer composite materials due to water in the free volumes of the polymer. These equations are applied to a specific polymer composite material during isothermal heating conditions. The thermal stresses obtained by the application of the theory are compared to measured results to verify the accuracy of the approach.

Cluster kinetics model for mixtures of glassformers

NASA Astrophysics Data System (ADS)

Brenskelle, Lisa A.; McCoy, Benjamin J.

2007-10-01

For glassformers we propose a binary mixture relation for parameters in a cluster kinetics model previously shown to represent pure compound data for viscosity and dielectric relaxation as functions of either temperature or pressure. The model parameters are based on activation energies and activation volumes for cluster association-dissociation processes. With the mixture parameters, we calculated dielectric relaxation times and compared the results to experimental values for binary mixtures. Mixtures of sorbitol and glycerol (seven compositions), sorbitol and xylitol (three compositions), and polychloroepihydrin and polyvinylmethylether (three compositions) were studied.

Solvatochromism and preferential solvation of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone by UV-vis absorption and laser-induced fluorescence measurements

NASA Astrophysics Data System (ADS)

Sasirekha, V.; Vanelle, P.; Terme, T.; Ramakrishnan, V.

2008-12-01

Solvation characteristics of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone ( 1) in pure and binary solvent mixtures have been studied by UV-vis absorption spectroscopy and laser-induced fluorescence techniques. The binary solvent mixtures used as CCl 4 (tetrachloromethane)-DMF ( N, N-dimethylformamide), AN (acetonitrile)-DMSO (dimethylsulfoxide), CHCl 3 (chloroform)-DMSO, CHCl 3-MeOH (methanol), and MeOH-DMSO. The longest wavelength band of 1 has been studied in pure solvents as well as in binary solvent mixtures as a function of the bulk mole fraction. The Vis absorption band maxima show an unusual blue shift with increasing solvent polarity. The emission maxima of 1 show changes with varying the pure solvents and the composition in the case of binary solvent mixtures. Non-ideal solvation characteristics are observed in all binary solvent mixtures. It has been observed that the quantity [ ν-(Xν+Xν)] serves as a measure of the extent of preferential solvation, where ν˜ and X are the position of band maximum in wavenumbers (cm -1) and the bulk mole fraction values, respectively. The preferential solvation parameters local mole fraction ( X2L), solvation index ( δs2), and exchange constant ( k12) are evaluated.

Physicochemical Properties of Glycine-Based Ionic Liquid [QuatGly-OEt][EtOSO3] (2-Ethoxy-1-ethyl-1,1-dimethyl-2-oxoethanaminium ethyl sulfate) and Its Binary Mixtures with Poly(ethylene glycol) (Mw = 200) at Various Temperatures

PubMed Central

Wu, Tzi-Yi; Chen, Bor-Kuan; Hao, Lin; Lin, Yuan-Chung; Wang, H. Paul; Kuo, Chung-Wen; Sun, I-Wen

2011-01-01

This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL) [QuatGly-OEt][EtOSO3] by NMR, elementary analysis and water content. Thermophysical properties such as density, ρ, viscosity, η, refractive index, n, and conductivity, κ, for the binary mixture of [QuatGly-OEt][EtOSO3] with poly(ethylene glycol) (PEG) [Mw = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO3] and its binary mixture can be described by an empirical polynomial equation and by the Vogel-Tammann-Fucher (VTF) equation, respectively. The thermal expansion coefficient of the ILs is ascertained using the experimental density results, and the excess volume expansivity is evaluated. The negative values of excess molar volume for the mixture indicate the ion-dipole interactions and packing between IL and PEG oligomer. The results of binary excess property (VmE ) and deviations (Δη, Δxn, ΔΨn, ΔxR, and ΔΨR) are discussed in terms of molecular interactions and molecular structures in the binary mixture. PMID:22272102

Phase behaviors of binary mixtures composed of electron-rich and electron-poor triphenylene discotic liquid crystals

NASA Astrophysics Data System (ADS)

An, Lingling; Jing, Min; Xiao, Bo; Bai, Xiao-Yan; Zeng, Qing-Dao; Zhao, Ke-Qing

2016-09-01

Disk-like liquid crystals (DLCs) can self-assemble to ordered columnar mesophases and are intriguing one-dimensional organic semiconductors with high charge carrier mobility. To improve their applicable property of mesomorphic temperature ranges, we exploit the binary mixtures of electronic donor-acceptor DLC materials. The electron-rich 2,3,6,7,10,11-hexakis(alkoxy)triphenylenes (C4, C6, C8, C10, C12) and an electron-deficient tetrapentyl triphenylene-2,3,6,10-tetracarboxylate have been prepared and their binary mixtures have been investigated. The mesomorphism of the 1:1 (molar ratio) mixtures has been characterized by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and small angel x-ray scattering (SAXS). The self-assembled monolayer structure of a discogen on a solid-liquid interface has been imaged by the high resolution scanning tunneling microscopy (STM). The match of peripheral chain length has important influence on the mesomorphism of the binary mixtures. Project supported by the National Natural Science Foundation of China (Grant Nos. 51273133 and 51443004).

A rapid Fourier transform infrared spectroscopic method for analysis of certain proton pump inhibitors in binary and ternary mixtures

NASA Astrophysics Data System (ADS)

Khashaba, Pakinaz Y.; Ali, Hassan Refat H.; El-Wekil, Mohamed M.

2018-02-01

A simple and non-destructive FTIR method was used to determine certain proton pump inhibitors (PPIs) in binary and ternary mixtures. Proton pump inhibitors (PPIs); omeprazole (OMZ), esomeprazole (EZM), lansoprazole (LAN), pantoprazole sodium (PAN sodium) and rabeprazole sodium (RAB sodium) in binary mixture with domperidone (DOM) and ternary mixture of OMZ, clarithromycin (CLM) and tinidazole (TNZ) were determined in the solid-state by FTIR spectroscopy for the first time. The method was validated according to ICH-guidelines where linearity was ranged from 20 to 850 μg/g and 20-360 μg/g for PPIs and DOM, respectively in binary mixtures and 10-400, 100-8000 and 150-14,000 μg/g for OMZ, CLM and TNZ, respectively. Limits of detection were found to be 6-100 and 9-100 μg/g for PPIs and DOM, respectively and 4, 40 and 50 μg/g for OMZ, CLM and TNZ, respectively. The method was applied successfully for determination of the cited drugs in their respective pharmaceutical dosage forms.

The Kirkwood-Buff theory of solutions and the local composition of liquid mixtures.

PubMed

Shulgin, Ivan L; Ruckenstein, Eli

2006-06-29

The present paper is devoted to the local composition of liquid mixtures calculated in the framework of the Kirkwood-Buff theory of solutions. A new method is suggested to calculate the excess (or deficit) number of various molecules around a selected (central) molecule in binary and multicomponent liquid mixtures in terms of measurable macroscopic thermodynamic quantities, such as the derivatives of the chemical potentials with respect to concentrations, the isothermal compressibility, and the partial molar volumes. This method accounts for an inaccessible volume due to the presence of a central molecule and is applied to binary and ternary mixtures. For the ideal binary mixture it is shown that because of the difference in the volumes of the pure components there is an excess (or deficit) number of different molecules around a central molecule. The excess (or deficit) becomes zero when the components of the ideal binary mixture have the same volume. The new method is also applied to methanol + water and 2-propanol + water mixtures. In the case of the 2-propanol + water mixture, the new method, in contrast to the other ones, indicates that clusters dominated by 2-propanol disappear at high alcohol mole fractions, in agreement with experimental observations. Finally, it is shown that the application of the new procedure to the ternary mixture water/protein/cosolvent at infinite dilution of the protein led to almost the same results as the methods involving a reference state.

Different spectrophotometric methods applied for the analysis of binary mixture of flucloxacillin and amoxicillin: A comparative study.

PubMed

Attia, Khalid A M; Nassar, Mohammed W I; El-Zeiny, Mohamed B; Serag, Ahmed

2016-05-15

Three different spectrophotometric methods were applied for the quantitative analysis of flucloxacillin and amoxicillin in their binary mixture, namely, ratio subtraction, absorbance subtraction and amplitude modulation. A comparative study was done listing the advantages and the disadvantages of each method. All the methods were validated according to the ICH guidelines and the obtained accuracy, precision and repeatability were found to be within the acceptable limits. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. So, they can be used for the routine analysis of flucloxacillin and amoxicillin in their binary mixtures. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of three veterinary antibiotics and their binary mixtures on two green alga species.

PubMed

Carusso, S; Juárez, A B; Moretton, J; Magdaleno, A

2018-03-01

The individual and combined toxicities of chlortetracycline (CTC), oxytetracycline (OTC) and enrofloxacin (ENF) have been examined in two green algae representative of the freshwater environment, the international standard strain Pseudokichneriella subcapitata and the native strain Ankistrodesmus fusiformis. The toxicities of the three antibiotics and their mixtures were similar in both strains, although low concentrations of ENF and CTC + ENF were more toxic in A. fusiformis than in the standard strain. The toxicological interactions of binary mixtures were predicted using the two classical models of additivity: Concentration Addition (CA) and Independent Action (IA), and compared to the experimentally determined toxicities over a range of concentrations between 0.1 and 10 mg L -1 . The CA model predicted the inhibition of algal growth in the three mixtures in P. subcapitata, and in the CTC + OTC and CTC + ENF mixtures in A. fusiformis. However, this model underestimated the experimental results obtained in the OTC + ENF mixture in A. fusiformis. The IA model did not predict the experimental toxicological effects of the three mixtures in either strain. The sum of the toxic units (TU) for the mixtures was calculated. According to these values, the binary mixtures CTC + ENF and OTC + ENF showed an additive effect, and the CTC + OTC mixture showed antagonism in P. subcapitata, whereas the three mixtures showed synergistic effects in A. fusiformis. Although A. fusiformis was isolated from a polluted river, it showed a similar sensitivity with respect to P. subcapitata when it was exposed to binary mixtures of antibiotics. Copyright © 2017 Elsevier Ltd. All rights reserved.

How Is the Freezing Point of a Binary Mixture of Liquids Related to the Composition? A Guided Inquiry Experiment

ERIC Educational Resources Information Center

Hunnicutt, Sally S.; Grushow, Alexander; Whitnell, Rob

2017-01-01

The principles of process-oriented guided inquiry learning (POGIL) are applied to a binary solid-liquid mixtures experiment. Over the course of two learning cycles, students predict, measure, and model the phase diagram of a mixture of fatty acids. The enthalpy of fusion of each fatty acid is determined from the results. This guided inquiry…

Experimental investigation of thermodynamic properties of binary mixture of acetic acid + n-butanol and acetic acid + water at temperature from 293.15 K to 343.15 K

NASA Astrophysics Data System (ADS)

Paul, M. Danish John; Shruthi, N.; Anantharaj, R.

2018-04-01

The derived thermodynamic properties like excess molar volume, partial molar volume, excess partial molar volume and apparent volume of binary mixture of acetic acid + n-butanolandacetic acid + water has been investigated using measured density of mixtures at temperatures from 293.15 K to 343.15.

Getting More Ecologically Relevant Information from Laboratory Tests: Recovery of Lemna minor After Exposure to Herbicides and Their Mixtures.

PubMed

Knežević, Varja; Tunić, Tanja; Gajić, Pero; Marjan, Patricija; Savić, Danko; Tenji, Dina; Teodorović, Ivana

2016-11-01

Recovery after exposure to herbicides-atrazine, isoproturon, and trifluralin-their binary and ternary mixtures, was studied under laboratory conditions using a slightly adapted standard protocol for Lemna minor. The objectives of the present study were (1) to compare empirical to predicted toxicity of selected herbicide mixtures; (2) to assess L. minor recovery potential after exposure to selected individual herbicides and their mixtures; and (3) to suggest an appropriate recovery potential assessment approach and endpoint in a modified laboratory growth inhibition test. The deviation of empirical from predicted toxicity was highest in binary mixtures of dissimilarly acting herbicides. The concentration addition model slightly underestimated mixture effects, indicating potential synergistic interactions between photosynthetic inhibitors (atrazine and isoproturon) and a cell mitosis inhibitor (trifluralin). Recovery after exposure to the binary mixture of atrazine and isoproturon was fast and concentration-independent: no significant differences between relative growth rates (RGRs) in any of the mixtures (IC10 Mix , 25 Mix , and 50 Mix ) versus control level were recorded in the last interval of the recovery phase. The recovery of the plants exposed to binary and ternary mixtures of dissimilarly acting herbicides was strictly concentration-dependent. Only plants exposed to IC10 Mix , regardless of the herbicides, recovered RGRs close to control level in the last interval of the recovery phase. The inhibition of the RGRs in the last interval of the recovery phase compared with the control level is a proposed endpoint that could inform on reversibility of the effects and indicate possible mixture effects on plant population recovery potential.

Method of making molecularly doped composite polymer material

DOEpatents

Affinito, John D [Tucson, AZ; Martin, Peter M [Kennewick, WA; Graff, Gordon L [West Richland, WA; Burrows, Paul E [Kennewick, WA; Gross, Mark E. , Sapochak, Linda S.

2005-06-21

A method of making a composite polymer of a molecularly doped polymer. The method includes mixing a liquid polymer precursor with molecular dopant forming a molecularly doped polymer precursor mixture. The molecularly doped polymer precursor mixture is flash evaporated forming a composite vapor. The composite vapor is cryocondensed on a cool substrate forming a composite molecularly doped polymer precursor layer, and the cryocondensed composite molecularly doped polymer precursor layer is cross linked thereby forming a layer of the composite polymer layer of the molecularly doped polymer.

Viscosity of nonelectrolyte liquid mixtures. IV. Binary mixtures containing p-Dioxane

NASA Astrophysics Data System (ADS)

Oswal, S. L.; Oswal, P.; Phalak, R. P.

1996-11-01

Measurements of the viscosity η and density p are reported for eight binary mixtures of p-dioxane with methylcyclohexane, l-chlorohexane, l-bromohexane, p-xylene, propylbenzene, methyl acetate, butyl acetate. anyl acetate at 303.15 K. The viscosity data haw been correlated with the equations of Grunbeng Nissan. of McAllister, and of Auslaendcr. The relation among the excess viscosity Δ In η, excess Gibbs energy of activation ΔG* E of viscous flow. and intermolecular interaction in these mixtures is discussed.

Physical Identification of Binary System of Gliclazide-Hydrophilic Polymers Using X-Ray Diffraction

NASA Astrophysics Data System (ADS)

Rachmawati, H.; Yatinasari, Faizatun, Syarie, S. A.

2008-03-01

The formation of binary system in pharmaceutical solid state is aimed to improve the physicochemical characteristics of active compound, such as its solubility. To identify the physical change of the binary system including crystallinity or particle morphology, there are many methods can be applied. In present report, we study the physical interaction of the binary system of gliclazide and hydrophilic polymers. In this binary system, gliclazide was either dispersed or mixed with polyvinyl pirrolidone (PVP K30) or polyethylene glycol (PEG 6000). The dispersion system of gliclazide in the polymeric carriers was prepared by solvation-evaporation method, using dichloromethane/methylene chloride as an organic solvent. The physical characterization of both dispersed and mixed of gliclazide was studied using X-ray diffraction at interval 6-50 °/2θ. As a comparison, the same procedure was performed for pure gliclazide. To confirm the diffractogram of this binary system, Fourier Transform Infrared (FT-IR) spectroscopy was carried out as well. Both diffarctogram and FT-IR spectra revealed that there was no new compound formed in the solid dispersion system of gliclazide:PEG 6000 and gliclazide:PVP K30. In contrast, the solubility as well as the dissolution rate of gliclazide in the presence of both hydrophilic polymers was increased as compared to pure gliclazide. We conclude therefore that solvatation followed by evaporation of gliclazide in the presence of either PEG 6000 or PVP K30 did not alter its crystalline characteristic. The improved of gliclazide solubility in the binary system might due to other mechanism such as increased in the wettability and the hydrophylicity effect of the polymers.

Individual and combined in vitro (anti)androgenic effects of certain food additives and cosmetic preservatives.

PubMed

Pop, Anca; Drugan, Tudor; Gutleb, Arno C; Lupu, Diana; Cherfan, Julien; Loghin, Felicia; Kiss, Béla

2016-04-01

The individual and combined (binary mixtures) (anti)androgenic effect of butylparaben (BuPB), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and propyl gallate (PG) was evaluated using the MDA-kb2 cell line. Exposing these cells to AR agonists results in the expression of the reporter gene (encoding for luciferase) and luminescence can be measured in order to monitor the activity of the reporter protein. In case of the evaluation of the anti-androgenic effect, the individual test compounds or binary mixtures were tested in the presence of a fixed concentration of a strong AR agonist (1000 pM 5-alpha-dihydrotestosterone; DHT). Cell viability was assessed using a resazurin based assay. For PG, this is the first report in the literature concerning its (anti)androgenic activity. In case of both individual and mixture testing none of the compounds or binary combinations showed androgenic activity. When tested in the presence of DHT, BuPB, BHA and BHT proved to be weak anti-androgens and this was confirmed during the evaluation of binary mixtures (BuPB+BHA, BuPB+BHT and BHA+BHT). Besides performing the in vitro testing of the binary combinations, two mathematical models (dose addition and response addition) were evaluated in terms of accuracy of prediction of the anti-androgenic effect of the selected binary mixtures. The dose addition model guaranteed a good correlation between the experimental and predicted data. However, no estimation was possible in case of mixtures containing PG, due to the lack of effect of the compound in case of the individual testing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contrasting performance of donor-acceptor copolymer pairs in ternary blend solar cells and two-acceptor copolymers in binary blend solar cells.

PubMed

Khlyabich, Petr P; Rudenko, Andrey E; Burkhart, Beate; Thompson, Barry C

2015-02-04

Here two contrasting approaches to polymer-fullerene solar cells are compared. In the first approach, two distinct semi-random donor-acceptor copolymers are blended with phenyl-C61-butyric acid methyl ester (PC61BM) to form ternary blend solar cells. The two poly(3-hexylthiophene)-based polymers contain either the acceptor thienopyrroledione (TPD) or diketopyrrolopyrrole (DPP). In the second approach, semi-random donor-acceptor copolymers containing both TPD and DPP acceptors in the same polymer backbone, termed two-acceptor polymers, are blended with PC61BM to give binary blend solar cells. The two approaches result in bulk heterojunction solar cells that have the same molecular active-layer components but differ in the manner in which these molecular components are mixed, either by physical mixing (ternary blend) or chemical "mixing" in the two-acceptor (binary blend) case. Optical properties and photon-to-electron conversion efficiencies of the binary and ternary blends were found to have similar features and were described as a linear combination of the individual components. At the same time, significant differences were observed in the open-circuit voltage (Voc) behaviors of binary and ternary blend solar cells. While in case of two-acceptor polymers, the Voc was found to be in the range of 0.495-0.552 V, ternary blend solar cells showed behavior inherent to organic alloy formation, displaying an intermediate, composition-dependent and tunable Voc in the range from 0.582 to 0.684 V, significantly exceeding the values achieved in the two-acceptor containing binary blend solar cells. Despite the differences between the physical and chemical mixing approaches, both pathways provided solar cells with similar power conversion efficiencies, highlighting the advantages of both pathways toward highly efficient organic solar cells.

Hard-sphere mixture excess free energy at infinite size ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tukur, N.M.; Hamad, E.Z.; Mansoori, G.A.

1999-02-01

This article presents the exact limiting value of the derivative of the excess Helmholtz energy, A{sup E}, with respect to molecular size at constant temperature, density and composition for a binary mixture of hard spheres with an infinite size ratio ({sigma}{sub 11}/{sigma}{sub 22}{r_arrow}{infinity}); i.e., lim{sub {sigma}{sub 22}{r_arrow}0}[({partial_derivative}A{sub hs}{sup E}/RT)/{partial_derivative}{sigma}{sub 22}]{sub T,{rho},x,{sigma}{sub 11}}=({pi}/2){rho}x{sub 1}x{sub 2}{sigma}{sub 11}{sup 2}/(1{minus}({pi}/6){rho}x{sub 1}{sigma}{sub 11}{sup 3}). This limiting value is compared with the Mansoori{endash}Carnahan{endash}Starling{endash}Leland (MCSL) and also used to test the limits of some commonly used models in estimating the excess free energy of solvents in mixtures or polymer solutions. The models evaluated include the van Laar,more » Wilson, Edmond{endash}Ogston, Flory{endash}Huggins, Lacome{endash}Sanchez, Scott{endash}Magat, and Chen {ital et al.} It is shown that while the MCSL equation of state produces the same limiting value as the exact value reported here the other mixture models deviate from the exact value. This expression may be utilized to correct the mixture theories at their infinite size ratio limits. {copyright} {ital 1999 American Institute of Physics.}« less

Statistical mechanics of binary mixture adsorption in metal-organic frameworks in the osmotic ensemble.

PubMed

Dunne, Lawrence J; Manos, George

2018-03-13

Although crucial for designing separation processes little is known experimentally about multi-component adsorption isotherms in comparison with pure single components. Very few binary mixture adsorption isotherms are to be found in the literature and information about isotherms over a wide range of gas-phase composition and mechanical pressures and temperature is lacking. Here, we present a quasi-one-dimensional statistical mechanical model of binary mixture adsorption in metal-organic frameworks (MOFs) treated exactly by a transfer matrix method in the osmotic ensemble. The experimental parameter space may be very complex and investigations into multi-component mixture adsorption may be guided by theoretical insights. The approach successfully models breathing structural transitions induced by adsorption giving a good account of the shape of adsorption isotherms of CO 2 and CH 4 adsorption in MIL-53(Al). Binary mixture isotherms and co-adsorption-phase diagrams are also calculated and found to give a good description of the experimental trends in these properties and because of the wide model parameter range which reproduces this behaviour suggests that this is generic to MOFs. Finally, a study is made of the influence of mechanical pressure on the shape of CO 2 and CH 4 adsorption isotherms in MIL-53(Al). Quite modest mechanical pressures can induce significant changes to isotherm shapes in MOFs with implications for binary mixture separation processes.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

Statistical mechanics of binary mixture adsorption in metal-organic frameworks in the osmotic ensemble

NASA Astrophysics Data System (ADS)

Dunne, Lawrence J.; Manos, George

2018-03-01

Although crucial for designing separation processes little is known experimentally about multi-component adsorption isotherms in comparison with pure single components. Very few binary mixture adsorption isotherms are to be found in the literature and information about isotherms over a wide range of gas-phase composition and mechanical pressures and temperature is lacking. Here, we present a quasi-one-dimensional statistical mechanical model of binary mixture adsorption in metal-organic frameworks (MOFs) treated exactly by a transfer matrix method in the osmotic ensemble. The experimental parameter space may be very complex and investigations into multi-component mixture adsorption may be guided by theoretical insights. The approach successfully models breathing structural transitions induced by adsorption giving a good account of the shape of adsorption isotherms of CO2 and CH4 adsorption in MIL-53(Al). Binary mixture isotherms and co-adsorption-phase diagrams are also calculated and found to give a good description of the experimental trends in these properties and because of the wide model parameter range which reproduces this behaviour suggests that this is generic to MOFs. Finally, a study is made of the influence of mechanical pressure on the shape of CO2 and CH4 adsorption isotherms in MIL-53(Al). Quite modest mechanical pressures can induce significant changes to isotherm shapes in MOFs with implications for binary mixture separation processes. This article is part of the theme issue `Modern theoretical chemistry'.

A dual-ion imprinted polymer embedded in sol-gel matrix for the ultra trace simultaneous analysis of cadmium and copper.

PubMed

Bali Prasad, Bhim; Jauhari, Darshika; Verma, Archana

2014-03-01

In simultaneous determination of group of elements, there are inter-metallic interactions which result in a non-linear relationship between the peak current and ionic concentration for each of the element, at bare (unmodified) electrode. To resolve this problem, we have resorted, for the first time, to develop a modified pencil graphite electrode using a typical ion imprinted polymer network (dual-ion imprinted polymer embedded in sol-gel matrix (inorganic-organic hybrid nano-material)) for the simultaneous analysis of a binary mixture of Cd(II) and Cu(II) ions, without any complication of inter-metallic interactions and competitive bindings, in real samples. The adequate resolution of differential pulse anodic stripping voltammetry peaks by 725 mV (cf, 615 mV with unmodified electrode), without any cross-reactivity and the stringent detection limits as low as, 0.050 and 0.034 ng mL(-1) (S/N=3) for Cd(II) and Cu(II) ions, respectively by the proposed sensor can be considered useful for the primitive diagnosis of several chronic diseases in clinical settings. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of Tunable Surface Potential on the Structure of Spin-Cast Polymeric Blend Films

NASA Astrophysics Data System (ADS)

Hawker, C.; Huang, E.; Russell, T. P.

1998-03-01

The demixing of binary polymeric mixtures has been studied with various surface potentials. This was performed by spin casting polystyrene/poly(methyl methacrylate) mixtures on to silicon substrates that had been modified with an end-grafted random copolymer brush layer. The composition of the random copolymer brush, containing the same monomeric components as the homopolymers can be varied in a precise manner over the entire concentration range. Atomic force and optical microscopy were used to study the morphology formed during spin casting and after annealing. Further insight into the structure was gained by rinsing these films with preferential solvents to remove one of the constituents and by performing the microscopy measurements. Finally, x-ray photoelectron spectroscopy, XPS, was used to elucidate the composition of the film near the air/polymer interface. Our data show that the resulting thin film structure depends strongly on the composition of the end grafted random copolymer film. Furthermore, the effect of thickness, solvent used in casting, and annealing conditions will be addressed.

Modeling water partition in composite gels of BSA with gelatin following high pressure treatment.

PubMed

Semasaka, Carine; Mhaske, Pranita; Buckow, Roman; Kasapis, Stefan

2018-11-01

Changes in the structural properties of hydrogels made with gelatin and bovine serum albumin mixtures were recorded following exposure to high pressure at 300 MPa for 15 min at 10 and 80 °C. Dynamic oscillation, SEM, FTIR and blending law modelling were utilised to rationalise results. Pressurization at the low temperature end yielded continuous gelatin networks supporting discontinuous BSA inclusions, whereas an inverted dispersion was formed at the high temperature end with the continuous BSA network suspending the discontinuous gelatin inclusions. Lewis and Nielsen equations followed the mechanical properties of the composites thus arguing that solvent partition between the two phases was always in favour of the polymer forming the continuous network. As far as we are aware, this is the first attempt to elucidate the solvent partition in pressurised hydrogel composites using blending law theory. Outcomes were contrasted with earlier work where binary mixtures were subjected only to thermal treatment. Copyright © 2018. Published by Elsevier Ltd.

Application of wavelet and Fuorier transforms as powerful alternatives for derivative spectrophotometry in analysis of binary mixtures: A comparative study

NASA Astrophysics Data System (ADS)

Hassan, Said A.; Abdel-Gawad, Sherif A.

2018-02-01

Two signal processing methods, namely, Continuous Wavelet Transform (CWT) and the second was Discrete Fourier Transform (DFT) were introduced as alternatives to the classical Derivative Spectrophotometry (DS) in analysis of binary mixtures. To show the advantages of these methods, a comparative study was performed on a binary mixture of Naltrexone (NTX) and Bupropion (BUP). The methods were compared by analyzing laboratory prepared mixtures of the two drugs. By comparing performance of the three methods, it was proved that CWT and DFT methods are more efficient and advantageous in analysis of mixtures with overlapped spectra than DS. The three signal processing methods were adopted for the quantification of NTX and BUP in pure and tablet forms. The adopted methods were validated according to the ICH guideline where accuracy, precision and specificity were found to be within appropriate limits.

Temperature Dependence of Densities and Excess Molar Volumes of the Ternary Mixture (1-Butanol + Chloroform + Benzene) and its Binary Constituents (1-Butanol + Chloroform and 1-Butanol + Benzene)

NASA Astrophysics Data System (ADS)

Smiljanić, Jelena D.; Kijevčanin, Mirjana Lj.; Djordjević, Bojan D.; Grozdanić, Dušan K.; Šerbanović, Slobodan P.

2008-04-01

Densities ρ of the 1-butanol + chloroform + benzene ternary mixture and the 1-butanol + chloroform and 1-butanol + benzene binaries have been measured at six temperatures (288.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure, using an oscillating U-tube densimeter. From these densities, excess molar volumes ( V E) were calculated and fitted to the Redlich Kister equation for all binary mixtures and to the Nagata and Tamura equation for the ternary system. The Radojković et al. equation has been used to predict excess molar volumes of the ternary mixtures. Also, V E data of the binary systems were correlated by the van der Waals (vdW1) and Twu Coon Bluck Tilton (TCBT) mixing rules coupled with the Peng Robinson Stryjek Vera (PRSV) equation of state. The prediction and correlation of V E data for the ternary system were performed by the same models.

Immobilization of organic radioactive and non-radioactive liquid waste in a composite matrix

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galkin, Anatoliy; Gelis, Artem V.; Castiglioni, Andrew J.

A method for immobilizing liquid radioactive waste is provided, the method having the steps of mixing waste with polymer to form a non-liquid waste; contacting the non-liquid waste with a solidifying agent to create a mixture, heating the mixture to cause the polymer, waste, and filler to irreversibly bind in a solid phase, and compressing the solid phase into a monolith. The invention also provides a method for immobilizing liquid radioactive waste containing tritium, the method having the steps of mixing liquid waste with polymer to convert the liquid waste to a non-liquid waste, contacting the non-liquid waste with amore » solidifying agent to create a mixture, heating the mixture to form homogeneous, chemically stable solid phase, and compressing the chemically stable solid phase into a final waste form, wherein the polymer comprises approximately a 9:1 weight ratio mixture of styrene block co-polymers and cross linked co-polymers of acrylamides.« less

Synergic effects in the extraction of paracetamol from aqueous NaCl solution by the binary mixtures of diethyl ether and low molecular weight primary alcohols

NASA Astrophysics Data System (ADS)

Nikolić, G. M.; Živković, J. V.; Atanasković, D. S.; Nikolić, M. G.

2013-12-01

Liquid-liquid extraction of paracetamol from aqueous NaCl solutions was performed with diethyl ether, 1-propanol, 1-butanol, isobutanol, 1-pentanol, and binary mixtures diethyl ether/1-propanol, diethyl ether/1-butanol, and diethyl ether/isobutanol. Among the pure solvents investigated in this study best extraction efficacy was obtained with 1-butanol. Synergic effects in the extraction with binary mixtures was investigated and compared with some other systems used for the extraction of poorly extractable compounds. Results obtained in this study may be of both fundamental and practical importance.

Study of thermodynamic and acoustic behaviour of nicotinic acid in binary aqueous mixtures of D-lactose

NASA Astrophysics Data System (ADS)

Sharma, Ravi; Thakur, R. C.

2017-07-01

In the present study, the thermodynamic properties such as partial molar volumes, partial molar expansibilities, partial molar compressibilities, partial molar heat capacities and isobaric thermal expansion coefficient of different solutions of nicotinic acid in binary aqueous mixtures of D-lactose have been determined at different temperatures (298.15, 303.15, 308.15, 313.15) K. Masson's equation is used to interpret the data in terms of solute-solute and solute-solvent interactions. In the present study it has been found that nicotinic acid behaves as structure maker in aqueous and binary aqueous mixtures of D-lactose.

Phase behaviour, interactions, and structural studies of (amines+ionic liquids) binary mixtures.

PubMed

Jacquemin, Johan; Bendová, Magdalena; Sedláková, Zuzana; Blesic, Marijana; Holbrey, John D; Mullan, Claire L; Youngs, Tristan G A; Pison, Laure; Wagner, Zdeněk; Aim, Karel; Costa Gomes, Margarida F; Hardacre, Christopher

2012-05-14

We present a study on the phase equilibrium behaviour of binary mixtures containing two 1-alkyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide-based ionic liquids, [C(n)mim] [NTf(2)] (n=2 and 4), mixed with diethylamine or triethylamine as a function of temperature and composition using different experimental techniques. Based on this work, two systems showing an LCST and one system with a possible hourglass shape are measured. Their phase behaviours are then correlated and predicted by using Flory-Huggins equations and the UNIQUAC method implemented in Aspen. The potential of the COSMO-RS methodology to predict the phase equilibria was also tested for the binary systems studied. However, this methodology is unable to predict the trends obtained experimentally, limiting its use for systems involving amines in ionic liquids. The liquid-state structure of the binary mixture ([C(2)mim] [NTf(2)]+diethylamine) is also investigated by molecular dynamics simulation and neutron diffraction. Finally, the absorption of gaseous ethane by the ([C(2)mim][NTf(2)]+diethylamine) binary mixture is determined and compared with that observed in the pure solvents. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capture of trace sulfur gases from binary mixtures by single-walled carbon nanotube arrays: a molecular simulation study.

PubMed

Wang, Wenjuan; Peng, Xuan; Cao, Dapeng

2011-06-01

Adsorption of H(2)S and SO(2) pure gases and their selective capture from the H(2)S-CH(4), H(2)S-CO(2), SO(2)-N(2), and SO(2)-CO(2) binary mixtures by the single-walled carbon nanotubes (SWNT) are investigated via using the grand canonical Monte Carlo (GCMC) method. It is found that the (20, 20) SWNT with larger diameter shows larger capacity for H(2)S and SO(2) pure gases at T = 303 K, in which the uptakes reach 16.31 and 16.03 mmol/g, respectively. However, the (6,6) SWNT with small diameter exhibits the largest selectivity for binary mixtures containing trace sulfur gases at T = 303 K and P = 100 kPa. By investigating the effect of pore size on the separation of gas mixtures, we found that the optimized pore size is 0.81 nm for separation of H(2)S-CH(4), H(2)S-CO(2), and SO(2)-N(2) binary mixtures, while it is 1.09 nm for the SO(2)-CO(2) mixture. The effects of concentration and temperature on the selectivity of sulfide are also studied at the optimal pore size. It is found that the concentration (ppm) of sulfur components has little effect on selectivity of SWNTs for these binary mixtures. However, the selectivity decreases obviously with the increase of temperature. To improve the adsorption capacities, we further modify the surface of SWNTs with the functional groups. The selectivities of H(2)S-CO(2) and SO(2)-CO(2) mixtures are basically uninfluenced by the site density, while the increase of site density can improve the selectivity of H(2)S-CH(4) mixture doubly. It is expected that this work could provide useful information for sulfur gas capture.

Performance Enhancement of Polymer Solar Cells by Using Two Polymer Donors with Complementary Absorption Spectra.

PubMed

Lu, Heng; Zhang, Xuejuan; Li, Cuihong; Wei, Hedi; Liu, Qian; Li, Weiwei; Bo, Zhishan

2015-07-01

Performance enhancement of polymer solar cells (PSCs) is achieved by expanding the absorption of the active layer of devices. To better match the spectrum of solar radiation, two polymers with different band gaps are used as the donor material to fabricate ternary polymer cells. Ternary blend PSCs exhibit an enhanced short-circuit current density and open-circuit voltage in comparison with the corresponding HD-PDFC-DTBT (HD)- and DT-PDPPTPT (DPP)-based binary polymer solar cells, respectively. Ternary PSCs show a power conversion efficiency (PCE) of 6.71%, surpassing the corresponding binary PSCs. This work demonstrates that the fabrication of ternary PSCs by using two polymers with complementary absorption is an effective way to improve the device performance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical analysis for condensation heat transfer of binary refrigerant mixtures with annular flow in horizontal mini-tubes

NASA Astrophysics Data System (ADS)

Zhang, Hui-Yong; Li, Jun-Ming; Sun, Ji-Liang; Wang, Bu-Xuan

2016-01-01

A theoretical model is developed for condensation heat transfer of binary refrigerant mixtures in mini-tubes with diameter about 1.0 mm. Condensation heat transfer of R410A and R32/R134a mixtures at different mass fluxes and saturated temperatures are analyzed, assuming that the phase flow pattern is annular flow. The results indicate that there exists a maximum interface temperature at the beginning of condensation process for azeotropic and zeotropic mixtures and the corresponding vapor quality to the maximum value increases with mass flux. The effects of mass flux, heat flux, surface tension and tube diameter are analyzed. As expected, the condensation heat transfer coefficients increase with mass flux and vapor quality, and increase faster in high vapor quality region. It is found that the effects of heat flux and surface tension are not so obvious as that of tube diameter. The characteristics of condensation heat transfer of zeotropic mixtures are consistent to those of azeotropic refrigerant mixtures. The condensation heat transfer coefficients increase with the concentration of the less volatile component in binary mixtures.

NEUROBEHAVIORAL EVALUATIONS OF BINARY AND TERTIARY MIXTURES OF CHEMICALS: LESSIONS LEARNING.

EPA Science Inventory

The classical approach to the statistical analysis of binary chemical mixtures is to construct full dose-response curves for one compound in the presence of a range of doses of the second compound (isobolographic analyses). For interaction studies using more than two chemicals, ...

Characterization of Mixtures. Part 2: QSPR Models for Prediction of Excess Molar Volume and Liquid Density Using Neural Networks.

PubMed

Ajmani, Subhash; Rogers, Stephen C; Barley, Mark H; Burgess, Andrew N; Livingstone, David J

2010-09-17

In our earlier work, we have demonstrated that it is possible to characterize binary mixtures using single component descriptors by applying various mixing rules. We also showed that these methods were successful in building predictive QSPR models to study various mixture properties of interest. Here in, we developed a QSPR model of an excess thermodynamic property of binary mixtures i.e. excess molar volume (V(E) ). In the present study, we use a set of mixture descriptors which we earlier designed to specifically account for intermolecular interactions between the components of a mixture and applied successfully to the prediction of infinite-dilution activity coefficients using neural networks (part 1 of this series). We obtain a significant QSPR model for the prediction of excess molar volume (V(E) ) using consensus neural networks and five mixture descriptors. We find that hydrogen bond and thermodynamic descriptors are the most important in determining excess molar volume (V(E) ), which is in line with the theory of intermolecular forces governing excess mixture properties. The results also suggest that the mixture descriptors utilized herein may be sufficient to model a wide variety of properties of binary and possibly even more complex mixtures. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of binary mixtures of zinc, copper, cadmium, and nickel on the growth of the freshwater diatom Navicula pelliculosa and comparison with mixture toxicity model predictions.

PubMed

Nagai, Takashi; De Schamphelaere, Karel A C

2016-11-01

The authors investigated the effect of binary mixtures of zinc (Zn), copper (Cu), cadmium (Cd), and nickel (Ni) on the growth of a freshwater diatom, Navicula pelliculosa. A 7 × 7 full factorial experimental design (49 combinations in total) was used to test each binary metal mixture. A 3-d fluorescence microplate toxicity assay was used to test each combination. Mixture effects were predicted by concentration addition and independent action models based on a single-metal concentration-response relationship between the relative growth rate and the calculated free metal ion activity. Although the concentration addition model predicted the observed mixture toxicity significantly better than the independent action model for the Zn-Cu mixture, the independent action model predicted the observed mixture toxicity significantly better than the concentration addition model for the Cd-Zn, Cd-Ni, and Cd-Cu mixtures. For the Zn-Ni and Cu-Ni mixtures, it was unclear which of the 2 models was better. Statistical analysis concerning antagonistic/synergistic interactions showed that the concentration addition model is generally conservative (with the Zn-Ni mixture being the sole exception), indicating that the concentration addition model would be useful as a method for a conservative first-tier screening-level risk analysis of metal mixtures. Environ Toxicol Chem 2016;35:2765-2773. © 2016 SETAC. © 2016 SETAC.

Bioadhesive Controlled Metronidazole Release Matrix Based on Chitosan and Xanthan Gum

PubMed Central

Eftaiha, Ala’a F.; Qinna, Nidal; Rashid, Iyad S.; Al Remawi, Mayyas M.; Al Shami, Munther R.; Arafat, Tawfiq A.; Badwan, Adnan A.

2010-01-01

Metronidazole, a common antibacterial drug, was incorporated into a hydrophilic polymer matrix composed of chitosan xanthan gum mixture. Hydrogel formation of this binary chitosan-xanthan gum combination was tested for its ability to control the release of metronidazole as a drug model. This preparation (MZ-CR) was characterized by in vitro, ex vivo bioadhesion and in vivo bioavailability study. For comparison purposes a commercial extended release formulation of metronidazole (CMZ) was used as a reference. The in vitro drug-release profiles of metronidazole preparation and CMZ were similar in 0.1 M HCl and phosphate buffer pH 6.8. Moreover, metronidazole preparation and CMZ showed a similar detachment force to sheep stomach mucosa, while the bioadhesion of the metronidazole preparation was higher three times than CMZ to sheep duodenum. The results of in vivo study indicated that the absorption of metronidazole from the preparation was faster than that of CMZ. Also, MZ-CR leads to higher metronidazole Cmax and AUC relative to that of the CMZ. This increase in bioavailability might be explained by the bioadhesion of the preparation at the upper part of the small intestine that could result in an increase in the overall intestinal transit time. As a conclusion, formulating chitosan-xanthan gum mixture as a hydrophilic polymer matrix resulted in a superior pharmacokinetic parameters translated by better rate and extent of absorption of metronidazole. PMID:20559494

Investigation of the combined effect of MgO and PEG on the release profile of mefenamic acid prepared via hot-melt extrusion techniques.

PubMed

Alshehri, Sultan M; Tiwari, Roshan V; Alsulays, Bader B; Ashour, Eman A; Alshetaili, Abdullah S; Almutairy, Bjad; Park, Jun-Bom; Morott, Joseph; Sandhu, Bhupinder; Majumdar, Soumyajit; Repka, Michael A

2017-09-01

This study aimed to investigate the combined effect of magnesium oxide (MgO) as an alkalizer and polyethylene glycol (PEG) as a plasticizer and wetting agent in the presence of Kollidon® 12 PF and 17 PF polymer carriers on the release profile of mefenamic acid (MA), which was prepared via hot-melt extrusion technique. Various drug loads of MA and various ratios of the polymers, PEG 3350 and MgO were blended using a V-shell blender and extruded using a twin-screw extruder (16-mm Prism EuroLab, ThermoFisher Scientific, Carlsbad, CA) at different screw speeds and temperatures to prepare a solid dispersion system. Differential scanning calorimetry and X-ray diffraction data of the extruded material confirmed that the drug existed in the amorphous form, as evidenced by the absence of corresponding peaks. MgO and PEG altered the micro-environmental pH to be more alkaline (pH 9) and increased the hydrophilicity and dispersibility of the extrudates to enhance MA solubility and release, respectively. The in vitro release study demonstrated an immediate release for 2 h with more than 80% drug release within 45 min in matrices containing MgO and PEG in combination with polyvinylpyrrolidone when compared to the binary mixture, physical mixture and pure drug.

Lanthanide-Containing Polymer Microspheres by Multiple-Stage Dispersion Polymerization for Highly Multiplexed Bioassays

PubMed Central

Abdelrahman, Ahmed I.; Dai, Sheng; Thickett, Stuart C.; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A.

2009-01-01

We describe the synthesis and characterization of metal-encoded polystyrene microspheres by multiple-stage dispersion polymerization with diameters on the order of 2 µm and a very narrow size distribution. Different lanthanides were loaded into these microspheres through the addition of a mixture of LnCl3 salts and excess acrylic acid or acetoacetylethyl methacrylate (AAEM) dissolved in ethanol to the reaction after about 10% conversion of styrene, i.e., well after the particle nucleation stage was complete. Individual microspheres contain ca. 106 – 108 chelated lanthanide ions, of either a single element or a mixture of elements. These microspheres were characterized one-by-one utilizing a novel mass cytometer with an inductively coupled plasma (ICP) ionization source and time-of-flight (TOF) mass spectrometry detection. Microspheres containing a range of different metals at different levels of concentration were synthesized to meet the requirements of binary encoding and enumeration encoding protocols. With four different metals at five levels of concentration, we could achieve a variability of 624, and the strategy we report should allow one to obtain much larger variability. To demonstrate the usefulness of element-encoded beads for highly multiplexed immunoassays, we carried out a proof-of-principle model bioassay involving conjugation of mouse IgG to the surface of La and Tm containing particles, and its detection by an anti-mouse IgG bearing a metal-chelating polymer with Pr. PMID:19807075

Lanthanide-containing polymer microspheres by multiple-stage dispersion polymerization for highly multiplexed bioassays.

PubMed

Abdelrahman, Ahmed I; Dai, Sheng; Thickett, Stuart C; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A

2009-10-28

We describe the synthesis and characterization of metal-encoded polystyrene microspheres by multiple-stage dispersion polymerization with diameters on the order of 2 mum and a very narrow size distribution. Different lanthanides were loaded into these microspheres through the addition of a mixture of lanthanide salts (LnCl(3)) and excess acrylic acid (AA) or acetoacetylethyl methacrylate (AAEM) dissolved in ethanol to the reaction after about 10% conversion of styrene, that is, well after the particle nucleation stage was complete. Individual microspheres contain ca. 10(6)-10(8) chelated lanthanide ions, of either a single element or a mixture of elements. These microspheres were characterized one-by-one utilizing a novel mass cytometer with an inductively coupled plasma (ICP) ionization source and time-of-flight (TOF) mass spectrometry detection. Microspheres containing a range of different metals at different levels of concentration were synthesized to meet the requirements of binary encoding and enumeration encoding protocols. With four different metals at five levels of concentration, we could achieve a variability of 624, and the strategy we report should allow one to obtain much larger variability. To demonstrate the usefulness of element-encoded beads for highly multiplexed immunoassays, we carried out a proof-of-principle model bioassay involving conjugation of mouse IgG to the surface of La and Tm containing particles and its detection by an antimouse IgG bearing a metal-chelating polymer with Pr.

Study of thermodynamic and transport properties of binary liquid mixture of diesel with biodiesel at 298.15K

NASA Astrophysics Data System (ADS)

Suthar, Shyam Sunder; Purohit, Suresh

2018-05-01

Properties of diesel and biodiesel (produced from corn oil) are used. Densities and viscosities of binary mixture of diesel with biodiesel (produced from corn oil) have been computed by using liquid binary mixture law over the entire range of compositions at T=298.15K and atmospheric pressure. From the computed values of density and viscosities, viscosity deviation (Δη), the excess molar volume (VE) and excess Gibbs energy of activation of viscous flow (ΔG#E) have been calculated. The results of excess volume, excess Gibbs energy of activation of viscous flow and viscosity deviation have been fitted to Redlich -Kister models to estimate the binary coefficients. The results are communicated in terms of the molecular interactions and the best suited composition has been found.

Binary Mixtures of Permanganate and Chlorinated Volatile Organic Compounds in Groundwater Samples: Sample Preservation and Analysis

EPA Science Inventory

Ground water samples collected at sites where in-situ chemical oxidation (ISCO) has been deployed may contain binary mixtures of ground water contaminants and permanganate (MnO4-), an oxidant injected into the subsurface to destroy the contaminant. Commingling of the oxidant and ...

Seasonal nitrogen effects on nutritive value in binary mixtures of tall fescue and bermudagrass

USDA-ARS?s Scientific Manuscript database

Year-round forage production is feasible in much of the southeastern USA through utilization of cool- and warm-season forages. This study determined changes in herbage nutritive value in binary mixtures of cool-season, tall fescue [Schedonorus arundinaceus (Schreb.) Dumort], and warm-season, bermuda...

Thermal characteristics of oleochemical carbonate binary mixtures for potential latent heat storage

USDA-ARS?s Scientific Manuscript database

The present study examines the thermal properties of melting and solidification for binary mixtures between dodecyl carbonate (1a), tetradecyl carbonate (1b), hexadecyl carbonate (1c), and octadecyl carbonate (1d) by differential scanning calorimetry (DSC) in order to gain further understanding of t...

Establishment and yield of perennial grass monocultures and binary mixtures for bioenergy in North Dakota

USDA-ARS?s Scientific Manuscript database

To develop appropriate bioenergy production systems to match site-specific situations, establishment and yield were evaluated for switchgrass, intermediate wheatgrass, tall wheatgrass, and three binary mixtures at four sites in North Dakota from 2006 to 2011. Canopy cover at harvest for intermediat...

Cultivar x binary mixture interaction effect on agronomic traits in orchardgrass

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate and characterize the agronomic value, including dry matter yield and forage quality of 25 orchardgrass cultivars grown in monoculture and binary mixtures with alfalfa under supplemental irrigation from 2009 to 2012 at a Millville, UT, field site. Orchardgrass monoc...

The contribution of molecular relaxation in nitrogen to the absorption of sound in the atmosphere

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J.; Meredith, R. W.

1980-01-01

Results and statistical analysis are presented for sound absorption in N2-H2O binary mixtures at room temperature. Experimental procedure, temperature effects, and preliminary results are presented for sound absorption in N2-H2O binary mixtures at elevated temperatures.

Suspensions of polymer-grafted nanoparticles with added polymers-Structure and effective pair-interactions.

PubMed

Chandran, Sivasurender; Saw, Shibu; Kandar, A K; Dasgupta, C; Sprung, M; Basu, J K

2015-08-28

We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material-star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP:PS size ratios, ξ = 0.14 and 2.76 (where, ξ = Mg/Mm, Mg and Mm being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with ξ = 0.14 could be modeled reasonably well, while the structure of blends with ξ = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with ξ = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with ξ = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework to understand not only the structural behavior of PGNPs but also possibly their dynamics and thermo-mechanical properties as well.

Polymer useful for an ion exchange membrane

DOEpatents

Liang, Siwei; Lynd, Nathaniel A.

2017-03-14

The present invention provides for a polymer formed by reacting a first reactant polymer, or a mixture of first reactant polymers comprising different chemical structures, comprising a substituent comprising two or more nitrogen atoms (or a functional group/sidechain comprising a two or more nitrogen atoms) with a second reactant polymer, or a mixture of second reactant polymers comprising different chemical structures, comprising a halogen substituent (or a functional group/sidechain comprising a halogen).

Excess Volumes and Excess Isentropic Compressibilities of Binary Liquid Mixtures of Trichloroethylene with Esters at 303.15 K

NASA Astrophysics Data System (ADS)

Ramanaiah, S.; Rao, C. Narasimha; Nagaraja, P.; Venkateswarlu, P.

2015-11-01

Exces volumes, VE, and excess isentropic compressibilities, κSE, have been reported as a function of composition for binary liquid mixtures of trichloroethylene with ethyl acetate, n-propyl acetate, and n-butyl acetate at 303.15 K. Isentropic compressibilities are calculated using measured sound speeds and density data for pure components and for binary mixtures. Excess volumes and excess isentropic compressibilities are found to be negative for the three systems studied over the entire composition range at 303.15 K, whereas these values become more negative with an increase of carbon chain length. The results are discussed in terms of intermolecular interactions between unlike molecules.

Induced smectic phase in binary mixtures of twist-bend nematogens.

PubMed

Knežević, Anamarija; Dokli, Irena; Sapunar, Marin; Šegota, Suzana; Baumeister, Ute; Lesac, Andreja

2018-01-01

The investigation of liquid crystal (LC) mixtures is of great interest in tailoring material properties for specific applications. The recent discovery of the twist-bend nematic phase (N TB ) has sparked great interest in the scientific community, not only from a fundamental viewpoint, but also due to its potential for innovative applications. Here we report on the unexpected phase behaviour of a binary mixture of twist-bend nematogens. A binary phase diagram for mixtures of imino-linked cyanobiphenyl (CBI) dimer and imino-linked benzoyloxy-benzylidene (BB) dimer shows two distinct domains. While mixtures containing less than 35 mol % of BB possess a wide temperature range twist-bend nematic phase, the mixtures containing 55-80 mol % of BB exhibit a smectic phase despite that both pure compounds display a Iso-N-N TB -Cr phase sequence. The phase diagram shows that the addition of BB of up to 30 mol % significantly extends the temperature range of the N TB phase, maintaining the temperature range of the nematic phase. The periodicity, obtained by atomic force microscopy (AFM) imaging, is in the range of 6-7 nm. The induction of the smectic phase in the mixtures containing 55-80 mol % of BB was confirmed using polarising optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction. The origin of the intercalated smectic phase was unravelled by combined spectroscopic and computational methods and can be traced to conformational disorder of the terminal chains. These results show the importance of understanding the phase behaviour of binary mixtures, not only in targeting a wide temperature range but also in controlling the self-organizing processes.

Herbage nutritive value of tall fescue-bermudagrass binary mixtures fertilized with combinations of nitrogen fertilizer and poultry litter

USDA-ARS?s Scientific Manuscript database

Year-round forage production is feasible in much of the southeastern USA through utilization of cool- and warm-season forages. This study determined if productivity and nutritive value in binary mixtures of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] and bermudagrass [Cynodon dactylon (L...

ETHANOL, ACETIC ACID, AND WATER ADSORPTION FROM BINARY AND TERNARY LIQUID MIXTURES ON HIGH-SILICA ZEOLITES

EPA Science Inventory

Adsorption isotherms were measured for ethanol, acetic acid, and water adsorbed on high-silica ZSM-5 zeolite powder from binary and ternary liquid mixtures at room temperature. Ethanol and water adsorption on two high-silica ZSM-5 zeolites with different aluminum contents and a h...

Stability of fluctuating and transient aggregates of amphiphilic solutes in aqueous binary mixtures: Studies of dimethylsulfoxide, ethanol, and tert-butyl alcohol

NASA Astrophysics Data System (ADS)

Banerjee, Saikat; Bagchi, Biman

2013-10-01

In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tert-butyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures.

Continuous Wavelet Transform, a powerful alternative to Derivative Spectrophotometry in analysis of binary and ternary mixtures: A comparative study.

PubMed

Elzanfaly, Eman S; Hassan, Said A; Salem, Maissa Y; El-Zeany, Badr A

2015-12-05

A comparative study was established between two signal processing techniques showing the theoretical algorithm for each method and making a comparison between them to indicate the advantages and limitations. The methods under study are Numerical Differentiation (ND) and Continuous Wavelet Transform (CWT). These methods were studied as spectrophotometric resolution tools for simultaneous analysis of binary and ternary mixtures. To present the comparison, the two methods were applied for the resolution of Bisoprolol (BIS) and Hydrochlorothiazide (HCT) in their binary mixture and for the analysis of Amlodipine (AML), Aliskiren (ALI) and Hydrochlorothiazide (HCT) as an example for ternary mixtures. By comparing the results in laboratory prepared mixtures, it was proven that CWT technique is more efficient and advantageous in analysis of mixtures with severe overlapped spectra than ND. The CWT was applied for quantitative determination of the drugs in their pharmaceutical formulations and validated according to the ICH guidelines where accuracy, precision, repeatability and robustness were found to be within the acceptable limit. Copyright © 2015 Elsevier B.V. All rights reserved.

Simple views on critical binary liquid mixtures in porous glass

NASA Astrophysics Data System (ADS)

Tremblay, L.; Socol, S. M.; Lacelle, S.

2000-01-01

A simple scenario, different from previous attempts, is proposed to resolve the problem of the slow phase separation dynamics of binary liquid mixtures confined in porous Vycor glass. We demonstrate that simply mutual diffusion, renormalized by critical composition fluctuations and geometrical hindrance of the porous glass, accounts for the slow phase separation kinetics. Capillary invasion studies of porous Vycor glass by the critical isobutyric acid-water mixture, close to the consolute solution temperature, corroborate our analysis.

Less common applications of simulated moving bed chromatography in the pharmaceutical industry.

PubMed

Huthmann, E; Juza, M

2005-10-21

Simulated moving bed (SMB) chromatography is often perceived in the pharmaceutical industry as chromatographic method for separating binary mixtures, like racemates. However, SMB can also be used for unbalanced separations, i.e. binary mixtures of varying compositions and multi-component mixtures. These less common application modes of isocratic SMB chromatography are exemplified for four different compounds (racemates and diastereomers) and discussed in view of the so-called 'triangle theory' from an industrial perspective.

Adsorption of binary gas mixtures in heterogeneous carbon predicted by density functional theory: on the formation of adsorption azeotropes.

PubMed

Ritter, James A; Pan, Huanhua; Balbuena, Perla B

2010-09-07

Classical density functional theory (DFT) was used to predict the adsorption of nine different binary gas mixtures in a heterogeneous BPL activated carbon with a known pore size distribution (PSD) and in single, homogeneous, slit-shaped carbon pores of different sizes. By comparing the heterogeneous results with those obtained from the ideal adsorbed solution theory and with those obtained in the homogeneous carbon, it was determined that adsorption nonideality and adsorption azeotropes are caused by the coupled effects of differences in the molecular size of the components in a gas mixture and only slight differences in the pore sizes of a heterogeneous adsorbent. For many binary gas mixtures, selectivity was found to be a strong function of pore size. As the width of a homogeneous pore increases slightly, the selectivity for two different sized adsorbates may change from being greater than unity to less than unity. This change in selectivity can be accompanied by the formation of an adsorption azeotrope when this same binary mixture is adsorbed in a heterogeneous adsorbent with a PSD, like in BPL activated carbon. These results also showed that the selectivity exhibited by a heterogeneous adsorbent can be dominated by a small number of pores that are very selective toward one of the components in the gas mixture, leading to adsorption azeotrope formation in extreme cases.

Flash-point prediction for binary partially miscible mixtures of flammable solvents.

PubMed

Liaw, Horng-Jang; Lu, Wen-Hung; Gerbaud, Vincent; Chen, Chan-Cheng

2008-05-30

Flash point is the most important variable used to characterize fire and explosion hazard of liquids. Herein, partially miscible mixtures are presented within the context of liquid-liquid extraction processes. This paper describes development of a model for predicting the flash point of binary partially miscible mixtures of flammable solvents. To confirm the predictive efficacy of the derived flash points, the model was verified by comparing the predicted values with the experimental data for the studied mixtures: methanol+octane; methanol+decane; acetone+decane; methanol+2,2,4-trimethylpentane; and, ethanol+tetradecane. Our results reveal that immiscibility in the two liquid phases should not be ignored in the prediction of flash point. Overall, the predictive results of this proposed model describe the experimental data well. Based on this evidence, therefore, it appears reasonable to suggest potential application for our model in assessment of fire and explosion hazards, and development of inherently safer designs for chemical processes containing binary partially miscible mixtures of flammable solvents.

Densities and viscosities for binary mixtures of N-methyldiethanolamine + triethylene glycol monomethyl ether from 25 C to 70 C and N-methyldiethanolamine + ethanol mixtures at 40 C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henni, A.; Maham, Y.; Tontiwachwuthikul, P.

2000-04-01

Recent studies done on the absorption and desorption of acid gases (CO{sub 2}, H{sub 2}S) from natural gas, petroleum, and ammonia synthesis streams have shown that aqueous solutions of N-methyldiethanolamine (MDEA) can be used effectively for the selective removal of H{sub 2}S. This paper reports the measured values of the density and viscosity of binary mixtures of N-methyldiethanolamine (MDEA) and triethylene glycol monomethyl ether (TEGMME) at five temperatures in the range 25 C to 70 C over the whole concentration range. The authors also report the density and viscosity of the binary mixture MDEA + ethanol at 40 C. Themore » results are compared with data for aqueous mixtures and other alkanolamines when these are available. The derived excess molar volumes and viscosity deviations were correlated as a function of composition. The Grunberg-Nissan interaction energy constants are also reported.« less

Hot melt extrusion versus spray drying: hot melt extrusion degrades albendazole.

PubMed

Hengsawas Surasarang, Soraya; Keen, Justin M; Huang, Siyuan; Zhang, Feng; McGinity, James W; Williams, Robert O

2017-05-01

The purpose of this study was to enhance the dissolution properties of albendazole (ABZ) by the use of amorphous solid dispersions. Phase diagrams of ABZ-polymer binary mixtures generated from Flory-Huggins theory were used to assess miscibility and processability. Forced degradation studies showed that ABZ degraded upon exposure to hydrogen peroxide and 1 N NaOH at 80 °C for 5 min, and the degradants were albendazole sulfoxide (ABZSX), and ABZ impurity A, respectively. ABZ was chemically stable following exposure to 1 N HCl at 80 °C for one hour. Thermal degradation profiles show that ABZ, with and without Kollidon ® VA 64, degraded at 180 °C and 140 °C, respectively, which indicated that ABZ could likely be processed by thermal processing. Following hot melt extrusion, ABZ degraded up to 97.4%, while the amorphous ABZ solid dispersion was successfully prepared by spray drying. Spray-dried ABZ formulations using various types of acids (methanesulfonic acid, sulfuric acid and hydrochloric acid) and polymers (Kollidon ® VA 64, Soluplus ® and Eudragit ® E PO) were studied. The spray-dried ABZ with methanesulfonic acid and Kollidon ® VA 64 substantially improved non-sink dissolution in acidic media as compared to bulk ABZ (8-fold), physical mixture of ABZ:Kollidon ® VA 64 (5.6-fold) and ABZ mesylate salt (1.6-fold). No degradation was observed in the spray-dried product for up to six months and less than 5% after one-year storage. In conclusion, amorphous ABZ solid dispersions in combination with an acid and polymer can be prepared by spray drying to enhance dissolution and shelf-stability, whereas those made by melt extrusion are degraded.

Preferential solvation bromophenol blue in water-alcohol binary mixture.

PubMed

Dangui, Anayana Z; Santos, Vanessa M S; Gomes, Benhur S; de Castilho, Taiane S; Nicolini, Keller P; Nicolini, Jaqueline

2018-05-29

In this study, the perichromic behavior of bromophenol blue (BPB) in various binary solvent mixtures was investigated. The binary mixtures considered were comprised of water and methanol (MeOH), ethanol (EtOH), n-propanol (n-PrOH), isopropanol (iso-PrOH) or t-butanol (t-BuOH). The investigation of a preferential solvation model that considers the addition of small quantities of alcohol to water in the presence of bromophenol blue (BPB) is described in this paper. The data obtained were employed to study the preferential solvation (PS) of the probe. It was observed that with increases in the molar fraction of water the spontaneity of the system decreases. This can be explained by the high solubility of BPB in ethanol, with ∆G>0 at higher wavelengths (region rich in water with violet solution) and ∆G<0 at lower wavelengths (region rich in alcohol with yellow solution). The pK of the binary mixture changed in all solvents and for all ratios, and the higher the water ratio is the lower the pK In will be. In binary mixture, an increase in the hydrogen bond acceptor (HBA) nature of the solvents tested resulted in a bathochromic effect on the absorption band of BPB (Δλ=12nm). All of the data obtained showed a good nonlinear fit with the mathematical model (SD≤6.6×10 -3 ), suggesting that BPB has other potential applications besides its use as a pH indicator. Copyright © 2017. Published by Elsevier B.V.

Detection of cocrystal formation based on binary phase diagrams using thermal analysis.

PubMed

Yamashita, Hiroyuki; Hirakura, Yutaka; Yuda, Masamichi; Teramura, Toshio; Terada, Katsuhide

2013-01-01

Although a number of studies have reported that cocrystals can form by heating a physical mixture of two components, details surrounding heat-induced cocrystal formation remain unclear. Here, we attempted to clarify the thermal behavior of a physical mixture and cocrystal formation in reference to a binary phase diagram. Physical mixtures prepared using an agate mortar were heated at rates of 2, 5, 10, and 30 °C/min using differential scanning calorimetry (DSC). Some mixtures were further analyzed using X-ray DSC and polarization microscopy. When a physical mixture consisting of two components which was capable of cocrystal formation was heated using DSC, an exothermic peak associated with cocrystal formation was detected immediately after an endothermic peak. In some combinations, several endothermic peaks were detected and associated with metastable eutectic melting, eutectic melting, and cocrystal melting. In contrast, when a physical mixture of two components which is incapable of cocrystal formation was heated using DSC, only a single endothermic peak associated with eutectic melting was detected. These experimental observations demonstrated how the thermal events were attributed to phase transitions occurring in a binary mixture and clarified the relationship between exothermic peaks and cocrystal formation.

Tritium containing polymers having a polymer backbone substantially void of tritium

DOEpatents

Jensen, G.A.; Nelson, D.A.; Molton, P.M.

1992-03-31

A radioluminescent light source comprises a solid mixture of a phosphorescent substance and a tritiated polymer. The solid mixture forms a solid mass having length, width, and thickness dimensions, and is capable of self-support. In one aspect of the invention, the phosphorescent substance comprises solid phosphor particles supported or surrounded within a solid matrix by a tritium containing polymer. The tritium containing polymer comprises a polymer backbone which is essentially void of tritium. 2 figs.

Tritium containing polymers having a polymer backbone substantially void of tritium

DOEpatents

Jensen, George A.; Nelson, David A.; Molton, Peter M.

1992-01-01

A radioluminescent light source comprises a solid mixture of a phosphorescent substance and a tritiated polymer. The solid mixture forms a solid mass having length, width, and thickness dimensions, and is capable of self-support. In one aspect of the invention, the phosphorescent substance comprises solid phosphor particles supported or surrounded within a solid matrix by a tritium containing polymer. The tritium containing polymer comprises a polymer backbone which is essentially void of tritium.

Concentration addition and independent action model: Which is better in predicting the toxicity for metal mixtures on zebrafish larvae.

PubMed

Gao, Yongfei; Feng, Jianfeng; Kang, Lili; Xu, Xin; Zhu, Lin

2018-01-01

The joint toxicity of chemical mixtures has emerged as a popular topic, particularly on the additive and potential synergistic actions of environmental mixtures. We investigated the 24h toxicity of Cu-Zn, Cu-Cd, and Cu-Pb and 96h toxicity of Cd-Pb binary mixtures on the survival of zebrafish larvae. Joint toxicity was predicted and compared using the concentration addition (CA) and independent action (IA) models with different assumptions in the toxic action mode in toxicodynamic processes through single and binary metal mixture tests. Results showed that the CA and IA models presented varying predictive abilities for different metal combinations. For the Cu-Cd and Cd-Pb mixtures, the CA model simulated the observed survival rates better than the IA model. By contrast, the IA model simulated the observed survival rates better than the CA model for the Cu-Zn and Cu-Pb mixtures. These findings revealed that the toxic action mode may depend on the combinations and concentrations of tested metal mixtures. Statistical analysis of the antagonistic or synergistic interactions indicated that synergistic interactions were observed for the Cu-Cd and Cu-Pb mixtures, non-interactions were observed for the Cd-Pb mixtures, and slight antagonistic interactions for the Cu-Zn mixtures. These results illustrated that the CA and IA models are consistent in specifying the interaction patterns of binary metal mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

Statistics of wormlike chains. II. Phase transition of polymer liquid crystals and its mixture with low molecular weight liquid crystals

NASA Astrophysics Data System (ADS)

Zhang, W. X.; Zhao, S. R.; Sun, C. P.

1997-02-01

A general self-consistent field (SCF) for the mixture of polymer and low molecular weight (LMW) molecules has been derived by variation principle. Considering a Maier-Saupe type of interaction, the analytical expressions of the SCF for polymer liquid crystals (PLCs) and the mixture of PLCs and LMW liquid crystals are obtained, from which the phase behaviors of PLCs as well as the mixture are studied. The theoretical results are in agreement with experimental results by adjusting a parameter.

Secondhand Smoke-Prevalent Polycyclic Aromatic Hydrocarbon Binary Mixture-Induced Specific Mitogenic and Pro-inflammatory Cell Signaling Events in Lung Epithelial Cells.

PubMed

Osgood, Ross S; Upham, Brad L; Bushel, Pierre R; Velmurugan, Kalpana; Xiong, Ka-Na; Bauer, Alison K

2017-05-01

Low molecular weight polycyclic aromatic hydrocarbons (LMW PAHs; < 206.3 g/mol) are prevalent and ubiquitous environmental contaminants, presenting a human health concern, and have not been as thoroughly studied as the high MW PAHs. LMW PAHs exert their pulmonary effects, in part, through P38-dependent and -independent mechanisms involving cell-cell communication and the production of pro-inflammatory mediators known to contribute to lung disease. Specifically, we determined the effects of two representative LMW PAHs, 1-methylanthracene (1-MeA) and fluoranthene (Flthn), individually and as a binary PAH mixture on the dysregulation of gap junctional intercellular communication (GJIC) and connexin 43 (Cx43), activation of mitogen activated protein kinases (MAPK), and induction of inflammatory mediators in a mouse non-tumorigenic alveolar type II cell line (C10). Both 1-MeA, Flthn, and the binary PAH mixture of 1-MeA and Flthn dysregulated GJIC in a dose and time-dependent manner, reduced Cx43 protein, and activated the following MAPKs: P38, ERK1/2, and JNK. Inhibition of P38 MAPK prevented PAH-induced dysregulation of GJIC, whereas inhibiting ERK and JNK did not prevent these PAHs from dysregulating GJIC indicating a P38-dependent mechanism. A toxicogenomic approach revealed significant P38-dependent and -independent pathways involved in inflammation, steroid synthesis, metabolism, and oxidative responses. Genes in these pathways were significantly altered by the binary PAH mixture when compared with 1-MeA and Flthn alone suggesting interactive effects. Exposure to the binary PAH mixture induced the production and release of cytokines and metalloproteinases from the C10 cells. Our findings with a binary mixture of PAHs suggest that combinations of LMW PAHs may elicit synergistic or additive inflammatory responses which warrant further investigation and confirmation. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Secondhand Smoke-Prevalent Polycyclic Aromatic Hydrocarbon Binary Mixture-Induced Specific Mitogenic and Pro-inflammatory Cell Signaling Events in Lung Epithelial Cells

PubMed Central

Osgood, Ross S.; Upham, Brad L.; Bushel, Pierre R.; Velmurugan, Kalpana; Xiong, Ka-Na

2017-01-01

Abstract Low molecular weight polycyclic aromatic hydrocarbons (LMW PAHs; < 206.3 g/mol) are prevalent and ubiquitous environmental contaminants, presenting a human health concern, and have not been as thoroughly studied as the high MW PAHs. LMW PAHs exert their pulmonary effects, in part, through P38-dependent and -independent mechanisms involving cell-cell communication and the production of pro-inflammatory mediators known to contribute to lung disease. Specifically, we determined the effects of two representative LMW PAHs, 1-methylanthracene (1-MeA) and fluoranthene (Flthn), individually and as a binary PAH mixture on the dysregulation of gap junctional intercellular communication (GJIC) and connexin 43 (Cx43), activation of mitogen activated protein kinases (MAPK), and induction of inflammatory mediators in a mouse non-tumorigenic alveolar type II cell line (C10). Both 1-MeA, Flthn, and the binary PAH mixture of 1-MeA and Flthn dysregulated GJIC in a dose and time-dependent manner, reduced Cx43 protein, and activated the following MAPKs: P38, ERK1/2, and JNK. Inhibition of P38 MAPK prevented PAH-induced dysregulation of GJIC, whereas inhibiting ERK and JNK did not prevent these PAHs from dysregulating GJIC indicating a P38-dependent mechanism. A toxicogenomic approach revealed significant P38-dependent and -independent pathways involved in inflammation, steroid synthesis, metabolism, and oxidative responses. Genes in these pathways were significantly altered by the binary PAH mixture when compared with 1-MeA and Flthn alone suggesting interactive effects. Exposure to the binary PAH mixture induced the production and release of cytokines and metalloproteinases from the C10 cells. Our findings with a binary mixture of PAHs suggest that combinations of LMW PAHs may elicit synergistic or additive inflammatory responses which warrant further investigation and confirmation. PMID:28329830

Process to prepare stable trifluorostyrene containing compounds grafted to base polymers using a solvent/water mixture

DOEpatents

Roelofs, Mark Gerrit; Yang, Zhen-Yu; Han, Amy Qi

2010-06-15

A fluorinated ion exchange polymer is prepared by grafting at least one grafting monomer derived from trifluorostyrene on to at least one base polymer in a organic solvent/water mixture. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.

A simple approach to polymer mixture miscibility.

PubMed

Higgins, Julia S; Lipson, Jane E G; White, Ronald P

2010-03-13

Polymeric mixtures are important materials, but the control and understanding of mixing behaviour poses problems. The original Flory-Huggins theoretical approach, using a lattice model to compute the statistical thermodynamics, provides the basic understanding of the thermodynamic processes involved but is deficient in describing most real systems, and has little or no predictive capability. We have developed an approach using a lattice integral equation theory, and in this paper we demonstrate that this not only describes well the literature data on polymer mixtures but allows new insights into the behaviour of polymers and their mixtures. The characteristic parameters obtained by fitting the data have been successfully shown to be transferable from one dataset to another, to be able to correctly predict behaviour outside the experimental range of the original data and to allow meaningful comparisons to be made between different polymer mixtures.

Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Govindaiah, T. N., E-mail: tngovi.phy@gmail.com; Sreepad, H. R.; Sridhar, K. N.

2015-06-24

A binary mixture of abietic acid and orthophosphoric acid (H{sub 3}PO{sub 4}) exhibits co-existence of biphasic region of Nematic+Isotropic (N+I), lyotropic Nematic (ND) and Smectic-G (SmG) phases. The mixture exhibits N+I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I→N+I→N→SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.

Analyte species and concentration identification using differentially functionalized microcantilever arrays and artificial neural networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senesac, Larry R; Datskos, Panos G; Sepaniak, Michael J

2006-01-01

In the present work, we have performed analyte species and concentration identification using an array of ten differentially functionalized microcantilevers coupled with a back-propagation artificial neural network pattern recognition algorithm. The array consists of ten nanostructured silicon microcantilevers functionalized by polymeric and gas chromatography phases and macrocyclic receptors as spatially dense, differentially responding sensing layers for identification and quantitation of individual analyte(s) and their binary mixtures. The array response (i.e. cantilever bending) to analyte vapor was measured by an optical readout scheme and the responses were recorded for a selection of individual analytes as well as several binary mixtures. Anmore » artificial neural network (ANN) was designed and trained to recognize not only the individual analytes and binary mixtures, but also to determine the concentration of individual components in a mixture. To the best of our knowledge, ANNs have not been applied to microcantilever array responses previously to determine concentrations of individual analytes. The trained ANN correctly identified the eleven test analyte(s) as individual components, most with probabilities greater than 97%, whereas it did not misidentify an unknown (untrained) analyte. Demonstrated unique aspects of this work include an ability to measure binary mixtures and provide both qualitative (identification) and quantitative (concentration) information with array-ANN-based sensor methodologies.« less

Determination of molecular diffusion coefficient in n-alkane binary mixtures: empirical correlations.

PubMed

De Mezquia, D Alonso; Bou-Ali, M Mounir; Larrañaga, M; Madariaga, J A; Santamaría, C

2012-03-08

In this work we have measured the molecular diffusion coefficient of the n-alkane binary series nC(i)-nC(6), nC(i)-nC(10), and nC(i)-nC(12) at 298 K and 1 atm and a mass fraction of 0.5 by using the so-called sliding symmetric tubes technique. The results show that the diffusion coefficient at this concentration is proportional to the inverse viscosity of the mixture. In addition, we have also measured the diffusion coefficient of the systems nC(12)-nC(6), nC(12)-nC(7), and nC(12)-nC(8) as a function of concentration. From the data obtained, it is shown that the diffusion coefficient of the n-alkane binary mixtures at any concentration can be calculated from the molecular weight of the components and the dynamic viscosity of the corresponding mixture at 50% mass fraction.

Composition measurements of binary mixture droplets by rainbow refractometry.

PubMed

Wilms, J; Weigand, B

2007-04-10

So far, refractive index measurements by rainbow refractometry have been used to determine the temperature of single droplets and ensembles of droplets. Rainbow refractometry is, for the first time, to the best of our knowledge, applied to measure composition histories of evaporating, binary mixture droplets. An evaluation method is presented that makes use of Airy theory and the simultaneous size measurement by Mie scattering imaging. The method further includes an empirical correction function for a certain diameter and refractive index range. The measurement uncertainty was investigated by numerical simulations with Lorenz-Mie theory. For the experiments, an optical levitation setup was used allowing for long measurement periods. Temperature measurements of single-component droplets at different temperature levels are shown to demonstrate the accuracy of rainbow refractometry. Measurements of size and composition histories of binary mixture droplets are presented for two different mixtures. Experimental results show good agreement with numerical results using a rapid-mixing model.

Development and validation of new spectrophotometric ratio H-point standard addition method and application to gastrointestinal acting drugs mixtures.

PubMed

Yehia, Ali M

2013-05-15

New, simple, specific, accurate and precise spectrophotometric technique utilizing ratio spectra is developed for simultaneous determination of two different binary mixtures. The developed ratio H-point standard addition method (RHPSAM) was managed successfully to resolve the spectral overlap in itopride hydrochloride (ITO) and pantoprazole sodium (PAN) binary mixture, as well as, mosapride citrate (MOS) and PAN binary mixture. The theoretical background and advantages of the newly proposed method are presented. The calibration curves are linear over the concentration range of 5-60 μg/mL, 5-40 μg/mL and 4-24 μg/mL for ITO, MOS and PAN, respectively. Specificity of the method was investigated and relative standard deviations were less than 1.5. The accuracy, precision and repeatability were also investigated for the proposed method according to ICH guidelines. Copyright © 2013 Elsevier B.V. All rights reserved.

Development and validation of new spectrophotometric ratio H-point standard addition method and application to gastrointestinal acting drugs mixtures

NASA Astrophysics Data System (ADS)

Yehia, Ali M.

2013-05-01

New, simple, specific, accurate and precise spectrophotometric technique utilizing ratio spectra is developed for simultaneous determination of two different binary mixtures. The developed ratio H-point standard addition method (RHPSAM) was managed successfully to resolve the spectral overlap in itopride hydrochloride (ITO) and pantoprazole sodium (PAN) binary mixture, as well as, mosapride citrate (MOS) and PAN binary mixture. The theoretical background and advantages of the newly proposed method are presented. The calibration curves are linear over the concentration range of 5-60 μg/mL, 5-40 μg/mL and 4-24 μg/mL for ITO, MOS and PAN, respectively. Specificity of the method was investigated and relative standard deviations were less than 1.5. The accuracy, precision and repeatability were also investigated for the proposed method according to ICH guidelines.

Joint acute and endocrine disruptive toxicities of malathion, cypermethrin and prochloraz to embryo-larval zebrafish, Danio rerio.

PubMed

Guo, Dongmei; Wang, Yanhua; Qian, Yongzhong; Chen, Chen; Jiao, Bining; Cai, Leiming; Wang, Qiang

2017-01-01

It remains a daunting challenge to determine ecotoxicological risks of exposure to mixtures of endocrine disrupting chemicals (EDCs) in environmental toxicology. In the present study, we investigated acute and endocrine disruptive toxicities of cypermethrin (CPM), malathion (MAL), prochloraz (PRO) and their binary mixtures of MAL + CPM and MAL + PRO to the early life stages of zebrafish. In the acute lethal toxicity test, three pesticides exhibited different levels of toxicity to zebrafish larvae, and the order of toxicity was as follows: CPM > PRO > MAL. The binary mixture of MAL + CPM displayed a synergistic effect on zebrafish larvae after exposure for 24, 48, 72 and 96 h. However, binary mixture of MAL + PRO showed an antagonistic effect. To evaluate the estrogenic effect, the expression of genes in the hypothalamic-pituitary-gonadal axis was assessed after zebrafish embryos were exposed to CPM, MAL, PRO and their binary mixtures from blastula stage (1 h post-fertilization, 1 hpf) to 14 dpf (14 d post-fertilization). Our data indicated that the transcription patterns of many key genes (vtg1, vtg2, era, erβ1, erβ2, cyp19a1a and cyp19a1b) were affected in hatched zebrafish after exposure to CPM, MAL and PRO. Moreover, following exposure to binary mixtures of 1000 μg/L MAL +4 μg/L CPM and 1000 μg/L MAL +900 μg/L PRO, the gene expressions were significantly changed compared with the individual pesticides. Our data provided a better understanding of bidirectional interactions of toxic response induced by these pesticides. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synergism and Combinatorial Coding for Binary Odor Mixture Perception in Drosophila

PubMed Central

Chakraborty, Tuhin Subhra; Siddiqi, Obaid

2016-01-01

Most odors in the natural environment are mixtures of several compounds. Olfactory receptors housed in the olfactory sensory neurons detect these odors and transmit the information to the brain, leading to decision-making. But whether the olfactory system detects the ingredients of a mixture separately or treats mixtures as different entities is not well understood. Using Drosophila melanogaster as a model system, we have demonstrated that fruit flies perceive binary odor mixtures in a manner that is heavily dependent on both the proportion and the degree of dilution of the components, suggesting a combinatorial coding at the peripheral level. This coding strategy appears to be receptor specific and is independent of interneuronal interactions. PMID:27588303

Harnessing Active Fins to Segregate Nanoparticles from Binary Mixtures

NASA Astrophysics Data System (ADS)

Liu, Ya; Kuksenok, Olga; Bhattacharya, Amitabh; Ma, Yongting; He, Ximin; Aizenberg, Joanna; Balazs, Anna

2014-03-01

One of the challenges in creating high-performance polymeric nanocomposites for optoelectronic applications, such as bilayer solar cells, is establishing effective and facile routes for controlling the properties of interface and segregation of binary particles with hole conductor particles and electron conductor particles. We model nanocomposites that encompass binary particles and binary blends in a microchannel. An array of oscillating microfins is immersed in the fluid and tethered to the floor of the microchannel; the fluid containing mixture of nanoparticles is driven along the channel by an imposed pressure gradient. During the oscillations, the fins with the specific chemical wetting reach the upper fluid when they are upright and are entirely within the lower stream when they are tilted. We introduce specific interaction between the fins and particulates in the solution. Fins can selectively ``catch'' target nanoparticles within the upper fluid stream and then release them into the lower stream. We focus on different modes of fins motion to optimize selective segregation of particles within binary mixture. Our approach provides an effective means of tailoring the properties and ultimate performance of the composites.

An Exercise on Calibration: DRIFTS Study of Binary Mixtures of Calcite and Dolomite with Partially Overlapping Spectral Features

ERIC Educational Resources Information Center

De Lorenzi Pezzolo, Alessandra

2013-01-01

Unlike most spectroscopic calibrations that are based on the study of well-separated features ascribable to the different components, this laboratory experience is especially designed to exploit spectral features that are nearly overlapping. The investigated system consists of a binary mixture of two commonly occurring minerals, calcite and…

Communication: Virial coefficients and demixing in highly asymmetric binary additive hard-sphere mixtures.

PubMed

López de Haro, Mariano; Tejero, Carlos F; Santos, Andrés

2013-04-28

The problem of demixing in a binary fluid mixture of highly asymmetric additive hard spheres is revisited. A comparison is presented between the results derived previously using truncated virial expansions for three finite size ratios with those that one obtains with the same approach in the extreme case in which one of the components consists of point particles. Since this latter system is known not to exhibit fluid-fluid segregation, the similarity observed for the behavior of the critical constants arising in the truncated series in all instances, while not being conclusive, may cast serious doubts as to the actual existence of a demixing fluid-fluid transition in disparate-sized binary additive hard-sphere mixtures.

Microwave dielectric study of polar liquids at 298 K

NASA Astrophysics Data System (ADS)

Maharolkar, Aruna P.; Murugkar, A.; Khirade, P. W.

2018-05-01

Present paper deals with study of microwave dielectric properties like dielectric constant, viscosity, density and refractive index for the binary mixtures of Dimethylsulphoxide (DMSO) and Methanol over the entire concentration range were measured at 298K. The experimental data further used to determine the excess properties viz. excess static dielectric constant, excess molar volume, excess viscosity& derived properties viz. molar refraction&Bruggman factor. The values of excess properties further fitted with Redlich-Kister (R-K Fit) equation to calculate the binary coefficients and standard deviation. The resulting excess parameters are used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures. Excess parameters indicate structure breaking factor in the mixture predominates in the system.

Thermo-acoustical molecular interaction study in binary mixtures of glycerol and ethylene glycol

NASA Astrophysics Data System (ADS)

Kaur, Kirandeep; Juglan, K. C.; Kumar, Harsh

2017-07-01

Ultrasonic velocity, density and viscosity are measured over the entire composition range for binary liquid mixtures of glycerol (CH2OH-CHOH-CH2OH) and ethylene glycol (HOCH2CH2OH) at different temperatures and constant frequency of 2MHz using ultrasonic interferometer, specific gravity bottle and viscometer respectively. Measured experimental values are used to obtained various acoustical parameters such as adiabatic compressibility, acoustic impedance, intermolecular free length, relaxation time, ultrasonic attenuation, effective molar weight, free volume, available volume, molar volume, Wada's constant, Rao's constant, Vander Waal's constant, internal pressure, Gibb's free energy and enthalpy. The variation in acoustical parameters are interpreted in terms of molecular interactions between the components of molecules of binary liquid mixtures.

Ordered alternating binary polymer nanodroplet array by sequential spin dewetting.

PubMed

Bhandaru, Nandini; Das, Anuja; Salunke, Namrata; Mukherjee, Rabibrata

2014-12-10

We report a facile technique for fabricating an ordered array of nearly equal-sized mesoscale polymer droplets of two constituent polymers (polystyrene, PS and poly(methyl methacrylate), PMMA) arranged in an alternating manner on a topographically patterned substrate. The self-organized array of binary polymers is realized by sequential spin dewetting. First, a dilute solution of PMMA is spin-dewetted on a patterned substrate, resulting in an array of isolated PMMA droplets arranged along the substrate grooves due to self-organization during spin coating itself. The sample is then silanized with octadecyltrichlorosilane (OTS), and subsequently, a dilute solution of PS is spin-coated on to it, which also undergoes spin dewetting. The spin-dewetted PS drops having a size nearly equal to the pre-existing PMMA droplets position themselves between two adjacent PMMA drops under appropriate conditions, forming an alternating binary polymer droplet array. The alternating array formation takes place for a narrow range of solution concentration for both the polymers and depends on the geometry of the substrate. The size of the droplets depends on the extent of confinement, and droplets as small as 100 nm can be obtained by this method, on a suitable template. The findings open up the possibility of creating novel surfaces having ordered multimaterial domains with a potential multifunctional capability.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

2014-04-22

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

2015-12-01

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

Effect of stirring on the safety of flammable liquid mixtures.

PubMed

Liaw, Horng-Jang; Gerbaud, Vincent; Chen, Chan-Cheng; Shu, Chi-Min

2010-05-15

Flash point is the most important variable employed to characterize fire and explosion hazard of liquids. The models developed for predicting the flash point of partially miscible mixtures in the literature to date are all based on the assumption of liquid-liquid equilibrium. In real-world environments, however, the liquid-liquid equilibrium assumption does not always hold, such as the collection or accumulation of waste solvents without stirring, where complete stirring for a period of time is usually used to ensure the liquid phases being in equilibrium. This study investigated the effect of stirring on the flash-point behavior of binary partially miscible mixtures. Two series of partially miscible binary mixtures were employed to elucidate the effect of stirring. The first series was aqueous-organic mixtures, including water+1-butanol, water+2-butanol, water+isobutanol, water+1-pentanol, and water+octane; the second series was the mixtures of two flammable solvents, which included methanol+decane, methanol+2,2,4-trimethylpentane, and methanol+octane. Results reveal that for binary aqueous-organic solutions the flash-point values of unstirred mixtures were located between those of the completely stirred mixtures and those of the flammable component. Therefore, risk assessment could be done based on the flammable component flash-point value. However, for the assurance of safety, it is suggested to completely stir those mixtures before handling to reduce the risk. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Polymeric compositions and their method of manufacture. [forming filled polymer systems using cryogenics

NASA Technical Reports Server (NTRS)

Moser, B. G.; Landel, R. F. (Inventor)

1972-01-01

Filled polymer compositions are made by dissolving the polymer binder in a suitable sublimable solvent, mixing the filler material with the polymer and its solvent, freezing the resultant mixture, and subliming the frozen solvent from the mixture from which it is then removed. The remaining composition is suitable for conventional processing such as compression molding or extruding. A particular feature of the method of manufacture is pouring the mixed solution slowly in a continuous stream into a cryogenic bath wherein frozen particles of the mixture result. The frozen individual particles are then subjected to the sublimation.

Selective Encaging of N2O in N2O-N2 Binary Gas Hydrates via Hydrate-Based Gas Separation.

PubMed

Yang, Youjeong; Shin, Donghoon; Choi, Seunghyun; Woo, Yesol; Lee, Jong-Won; Kim, Dongseon; Shin, Hee-Young; Cha, Minjun; Yoon, Ji-Ho

2017-03-21

The crystal structure and guest inclusion behaviors of nitrous oxide-nitrogen (N 2 O-N 2 ) binary gas hydrates formed from N 2 O/N 2 gas mixtures are determined through spectroscopic analysis. Powder X-ray diffraction results indicate that the crystal structure of all the N 2 O-N 2 binary gas hydrates is identified as the structure I (sI) hydrate. Raman spectra for the N 2 O-N 2 binary gas hydrate formed from N 2 O/N 2 (80/20, 60/40, 40/60 mol %) gas mixtures reveal that N 2 O molecules occupy both large and small cages of the sI hydrate. In contrast, there is a single Raman band of N 2 O molecules for the N 2 O-N 2 binary gas hydrate formed from the N 2 O/N 2 (20/80 mol %) gas mixture, indicating that N 2 O molecules are trapped in only large cages of the sI hydrate. From temperature-dependent Raman spectra and the Predictive Soave-Redlich-Kwong (PSRK) model calculation, we confirm the self-preservation of N 2 O-N 2 binary gas hydrates in the temperature range of 210-270 K. Both the experimental measurements and the PSRK model calculations demonstrate the preferential occupation of N 2 O molecules rather than N 2 molecules in the hydrate cages, leading to a possible process for separating N 2 O from gas mixtures via hydrate formation. The phase equilibrium conditions, pseudo-pressure-composition (P-x) diagram, and gas storage capacity of N 2 O-N 2 binary gas hydrates are discussed in detail.

Toxic effect of metal cation binary mixtures to the seaweed Gracilaria domingensis (Gracilariales, Rhodophyta).

PubMed

Mendes, Luiz Fernando; Stevani, Cassius Vinicius; Zambotti-Villela, Leonardo; Yokoya, Nair Sumie; Colepicolo, Pio

2014-01-01

The macroalga Gracilaria domingensis is an important resource for the food, pharmaceutical, cosmetic, and biotechnology industries. G. domingensis is at a part of the food web foundation, providing nutrients and microelements to upper levels. As seaweed storage metals in the vacuoles, they are considered the main vectors to magnify these toxic elements. This work describes the evaluation of the toxicity of binary mixtures of available metal cations based on the growth rates of G. domingensis over a 48-h exposure. The interactive effects of each binary mixture were determined using a toxic unit (TU) concept that was the sum of the relative contribution of each toxicant and calculated using the ratio between the toxicant concentration and its endpoint. Mixtures of Cd(II)/Cu(II) and Zn(II)/Ca(II) demonstrated to be additive; Cu(II)/Zn(II), Cu(II)/Mg(II), Cu(II)/Ca(II), Zn(II)/Mg(II), and Ca(II)/Mg(II) mixtures were synergistic, and all interactions studied with Cd(II) were antagonistic. Hypotheses that explain the toxicity of binary mixtures at the molecular level are also suggested. These results represent the first effort to characterize the combined effect of available metal cations, based on the TU concept on seaweed in a total controlled medium. The results presented here are invaluable to the understanding of seaweed metal cation toxicity in the marine environment, the mechanism of toxicity action and how the tolerance of the organism.

Adsorption and separation of binary and ternary mixtures of SO2, CO2 and N2 by ordered carbon nanotube arrays: grand-canonical Monte Carlo simulations.

PubMed

Rahimi, Mahshid; Singh, Jayant K; Müller-Plathe, Florian

2016-02-07

The adsorption and separation behavior of SO2-CO2, SO2-N2 and CO2-N2 binary mixtures in bundles of aligned double-walled carbon nanotubes is investigated using the grand-canonical Monte Carlo (GCMC) method and ideal adsorbed solution theory. Simulations were performed at 303 K with nanotubes of 3 nm inner diameter and various intertube distances. The results showed that the packing with an intertube distance d = 0 has the highest selectivity for SO2-N2 and CO2-N2 binary mixtures. For the SO2-CO2 case, the optimum intertube distance for having the maximum selectivity depends on the applied pressure, so that at p < 0.8 bar d = 0 shows the highest selectivity and at 0.8 bar < p < 2.5 bar, the highest selectivity belongs to d = 0.5 nm. Ideal adsorbed solution theory cannot predict the adsorption of the binary systems containing SO2, especially when d = 0. As the intertube distance is increased, the ideal adsorbed solution theory based predictions become closer to those of GCMC simulations. Only in the case of CO2-N2, ideal adsorbed solution theory is everywhere in good agreement with simulations. In a ternary mixture of all three gases, the behavior of SO2 and CO2 remains similar to that in a SO2-CO2 binary mixture because of the weak interaction between N2 molecules and CNTs.

Taste Mixture Interactions: Suppression, Additivity, and the Predominance of Sweetness

PubMed Central

Green, Barry G.; Lim, Juyun; Osterhoff, Floor; Blacher, Karen; Nachtigal, Danielle

2010-01-01

Most of what is known about taste interactions has come from studies of binary mixtures. The primary goal of this study was to determine whether asymmetries in suppression between stimuli in binary mixtures predict the perception of tastes in more complex mixtures (e.g., ternary, quaternary mixtures). Also of interest was the longstanding question of whether overall taste intensity derives from the sum of the tastes perceived within a mixture (perceptual additivity) or from the sum of the perceived intensities of the individual stimuli (stimulus additivity). Using the general Labeled Magnitude Scale together with a sip-and-spit procedure, we asked subjects to rate overall taste intensity and the sweetness, sourness, saltiness and bitterness of approximately equi- intense sucrose, NaCl, citric acid and QSO4 stimuli presented alone and in all possible binary, ternary and quaternary mixtures. The results showed a consistent pattern of mixture suppression in which sucrose sweetness tended to be both the least suppressed quality and the strongest suppressor of other tastes. The overall intensity of mixtures was found to be predicted best by perceptual additivity. A second experiment that was designed to rule out potentially confounding effects of the order of taste ratings and the temperature of taste solutions replicated the main findings of the first experiment. Overall, the results imply that mixture suppression favors perception of sweet carbohydrates in foods at the expense of other potentially harmful ingredients, such as high levels of sodium (saltiness) and potential poisons or spoilage (bitterness, sourness). PMID:20800076

Statistical Mechanical Theory of Coupled Slow Dynamics in Glassy Polymer-Molecule Mixtures

NASA Astrophysics Data System (ADS)

Zhang, Rui; Schweizer, Kenneth

The microscopic Elastically Collective Nonlinear Langevin Equation theory of activated relaxation in one-component supercooled liquids and glasses is generalized to polymer-molecule mixtures. The key idea is to account for dynamic coupling between molecule and polymer segment motion. For describing the molecule hopping event, a temporal casuality condition is formulated to self-consistently determine a dimensionless degree of matrix distortion relative to the molecule jump distance based on the concept of coupled dynamic free energies. Implementation for real materials employs an established Kuhn sphere model of the polymer liquid and a quantitative mapping to a hard particle reference system guided by the experimental equation-of-state. The theory makes predictions for the mixture dynamic shear modulus, activated relaxation time and diffusivity of both species, and mixture glass transition temperature as a function of molecule-Kuhn segment size ratio and attraction strength, composition and temperature. Model calculations illustrate the dynamical behavior in three distinct mixture regimes (fully miscible, bridging, clustering) controlled by the molecule-polymer interaction or chi-parameter. Applications to specific experimental systems will be discussed.

A non-additive repulsive contribution in an equation of state: The development for homonuclear square well chains equation of state validated against Monte Carlo simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trinh, Thi-Kim-Hoang; Laboratoire de Science des Procédés et des Matériaux; Passarello, Jean-Philippe, E-mail: Jean-Philippe.Passarello@lspm.cnrs.fr

This work consists of the adaptation of a non-additive hard sphere theory inspired by Malakhov and Volkov [Polym. Sci., Ser. A 49(6), 745–756 (2007)] to a square-well chain. Using the thermodynamic perturbation theory, an additional term is proposed that describes the effect of perturbing the chain of square well spheres by a non-additive parameter. In order to validate this development, NPT Monte Carlo simulations of thermodynamic and structural properties of the non-additive square well for a pure chain and a binary mixture of chains are performed. Good agreements are observed between the compressibility factors originating from the theory and thosemore » from molecular simulations.« less

Separation Potential for Multicomponent Mixtures: State-of-the Art of the Problem

NASA Astrophysics Data System (ADS)

Sulaberidze, G. A.; Borisevich, V. D.; Smirnov, A. Yu.

2017-03-01

Various approaches used in introducing a separation potential (value function) for multicomponent mixtures have been analyzed. It has been shown that all known potentials do not satisfy the Dirac-Peierls axioms for a binary mixture of uranium isotopes, which makes their practical application difficult. This is mainly due to the impossibility of constructing a "standard" cascade, whose role in the case of separation of binary mixtures is played by the ideal cascade. As a result, the only universal search method for optimal parameters of the separation cascade is their numerical optimization by the criterion of the minimum number of separation elements in it.

Surface tension of binary mixtures of water + N-methyldiethanolamine and ternary mixtures of this amine and water with monoethanolamine, diethanolamine, and 2-amino-2-methyl-1-propanol from 25 to 50 C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alvarez, E.; Rendo, R.; Sanjurjo, B.

1998-11-01

The surface tension of aqueous solutions of N-methyldiethanolamine and diethanolamine + N-methyldiethanolamine, monoethanolamine + N-methyldiethanolamine and 2-amino-2-methyl-1-propanol + N-methyldiethanolamine was measured at temperatures from 25 C to 50 C. For binary mixtures the concentration range was 0--50 mass % N-methyldiethanolamine, and for the tertiary mixtures the concentration range for each amine was 0--50 mass %. The experimental values were correlated with temperature and mole fraction. The maximum deviation in both cases was always less than 0.5%.

Transport properties of nonelectrolyte mixtures. IX. Viscosity coefficients for acetonitrile and for three mixtures of toluene+acetonitrile from 25 to 100°c at pressures up to 500 MPa

NASA Astrophysics Data System (ADS)

Dymond, J. H.; Awan, M. A.; Glen, N. F.; Isdale, J. D.

1991-05-01

A two-coil self-centering falling-body viscometer has been used to measure viscosity coefficients for acetonitrile and three binary mixtures of toluene+ acetonitrile at 25, 50, 75, and 100°C and pressures up to 500 MPa. The results for acetonitrile can be interpreted by an approach based on hard-sphere theory, with a roughness factor of 1.46. The binary-mixture data are well represented by the Grunberg and Nissan equation with a mixing parameter which is pressure and temperature dependent but composition independent.

Viscosities of nonelectrolyte liquid mixtures. II. Binary mixtures of n-hexane with alkanoates and bromoalkanoates

NASA Astrophysics Data System (ADS)

Oswal, S. L.; Dave, J. P.

1992-11-01

Viscosity measurements are reported for mixtures of ethyl ethanoate, ethyl propionate, ethyl butyrate, ethyl-2-bromopropionate, ethyl-3-bromopropionate, ethyl-2-bromobutyrate, and ethyl-4-bromobutyrate with n-hexane at 303.15 K. The viscosity data have been correlated with equations of Grunberg and Nissan, of McAllister, and of Auslaender. Furthermore, excess Gibbs energies of activation ΔG * E of viscous flow have been calculated with Eyring's theory of absolute reaction rates and values of ΔG * E for the present binary mixtures have been explained in terms of the dipole-dipole interaction in alkanoates and the intramolecular Br...O interaction in bromoalkanoates.

Viscosity minima in binary mixtures of ionic liquids + molecular solvents.

PubMed

Tariq, M; Shimizu, K; Esperança, J M S S; Canongia Lopes, J N; Rebelo, L P N

2015-05-28

The viscosity (η) of four binary mixtures (ionic liquids plus molecular solvents, ILs+MSs) was measured in the 283.15 < T/K < 363.15 temperature range. Different IL/MS combinations were selected in such a way that the corresponding η(T) functions exhibit crossover temperatures at which both pure components present identical viscosity values. Consequently, most of the obtained mixture isotherms, η(x), exhibit clear viscosity minima in the studied T-x range. The results are interpreted using auxiliary molecular dynamics (MD) simulation data in order to correlate the observed η(T,x) trends with the interactions in each mixture, including the balance between electrostatic forces and hydrogen bonding.

Refractive Index Mixing Rules and Excess Infrared Spectra of Binary Mixtures.

PubMed

Baranović, Goran

2017-05-01

Three refractive index mixing rules, Arago-Biot, Lorentz-Lorenz, and Newton, are generalized to complex refractive index and used to define infrared (IR) spectra of the corresponding ideal liquid mixtures. Using the measured optical constants n and k for acetonitrile-water mixtures (Bertie and Lan, 1997) the excess absorbances, A E  =  A obs  -  A ideal , are calculated. Relying upon the well-established properties of the acetonitrile-water mixtures, the interpretation of the excess absorbances is established that is essentially based on the understanding of a liquid as a set of oscillators. The set depends on the composition of the mixture and comprises oscillators as present in the pure components and oscillators perturbed by hydrogen bonding between unlike molecules. The main features of an excess spectrum can be established assuming chemical equilibria among various oscillators. The most informative parts of the spectrum of a yet unstudied binary system can well be observed and even qualitatively explained from the excess absorbance provided: first, a detailed vibrational study of the components has been done; and, second, it is well understood what actually is subtracted from A obs . As examples, the binary mixtures of ethynylbenzene and tetrachloroethylene and 2-ethynylpyridine and tetrachloroethylene are considered.

Combining nitrogen fertilizer with poultry litter in a binary mixture of tall fescue and bermudagrass

USDA-ARS?s Scientific Manuscript database

A common problem when poultry litter is applied to pastures in the southeastern USA is the buildup of soil P because of the difference in N-P-K ratio of the litter and plant requirements. This 2-yr study tested the theory that if the N requirement of a tall fescue-bermudagrass binary mixture is only...

A globally accurate theory for a class of binary mixture models

NASA Astrophysics Data System (ADS)

Dickman, Adriana G.; Stell, G.

The self-consistent Ornstein-Zernike approximation results for the 3D Ising model are used to obtain phase diagrams for binary mixtures described by decorated models, yielding the plait point, binodals, and closed-loop coexistence curves for the models proposed by Widom, Clark, Neece, and Wheeler. The results are in good agreement with series expansions and experiments.

On hydrodynamic phase field models for binary fluid mixtures

NASA Astrophysics Data System (ADS)

Yang, Xiaogang; Gong, Yuezheng; Li, Jun; Zhao, Jia; Wang, Qi

2018-05-01

Two classes of thermodynamically consistent hydrodynamic phase field models have been developed for binary fluid mixtures of incompressible viscous fluids of possibly different densities and viscosities. One is quasi-incompressible, while the other is incompressible. For the same binary fluid mixture of two incompressible viscous fluid components, which one is more appropriate? To answer this question, we conduct a comparative study in this paper. First, we visit their derivation, conservation and energy dissipation properties and show that the quasi-incompressible model conserves both mass and linear momentum, while the incompressible one does not. We then show that the quasi-incompressible model is sensitive to the density deviation of the fluid components, while the incompressible model is not in a linear stability analysis. Second, we conduct a numerical investigation on coarsening or coalescent dynamics of protuberances using the two models. We find that they can predict quite different transient dynamics depending on the initial conditions and the density difference although they predict essentially the same quasi-steady results in some cases. This study thus cast a doubt on the applicability of the incompressible model to describe dynamics of binary mixtures of two incompressible viscous fluids especially when the two fluid components have a large density deviation.

Field Implementation of Handheld FTIR Spectrometer for Polymer Content Determination and for Quality Control of RAP Mixtures : Research Project Capsule

DOT National Transportation Integrated Search

2017-10-01

The purpose of this research study is to determine if the implementation of FTIRS in Louisiana for determining polymer content in asphalt mixtures and for quality control of recycled asphalt mixtures is feasible. The ultimate objective is to develop ...

Thermodynamics of concentrated electrolyte mixtures and the prediction of mineral solubilities to high temperatures for mixtures in the system Na-K-Mg-Cl-SO 4-OH-H 2O

NASA Astrophysics Data System (ADS)

Pabalan, Roberto T.; Pitzer, Kenneth S.

1987-09-01

Mineral solubilities in binary and ternary electrolyte mixtures in the system Na-K-Mg-Cl-SO 4-OH-H 2O are calculated to high temperatures using available thermodynamic data for solids and for aqueous electrolyte solutions. Activity and osmotic coefficients are derived from the ion-interaction model of Pitzer (1973, 1979) and co-workers, the parameters of which are evaluated from experimentally determined solution properties or from solubility data in binary and ternary mixtures. Excellent to good agreement with experimental solubilities for binary and ternary mixtures indicate that the model can be successfully used to predict mineral-solution equilibria to high temperatures. Although there are currently no theoretical forms for the temperature dependencies of the various model parameters, the solubility data in ternary mixtures can be adequately represented by constant values of the mixing term θ ij and values of ψ ijk which are either constant or have a simple temperature dependence. Since no additional parameters are needed to describe the thermodynamic properties of more complex electrolyte mixtures, the calculations can be extended to equilibrium studies relevant to natural systems. Examples of predicted solubilities are given for the quaternary system NaCl-KCl-MgCl 2-H 2O.

Nonlinear Least-Squares Based Method for Identifying and Quantifying Single and Mixed Contaminants in Air with an Electronic Nose

PubMed Central

Zhou, Hanying; Homer, Margie L.; Shevade, Abhijit V.; Ryan, Margaret A.

2006-01-01

The Jet Propulsion Laboratory has recently developed and built an electronic nose (ENose) using a polymer-carbon composite sensing array. This ENose is designed to be used for air quality monitoring in an enclosed space, and is designed to detect, identify and quantify common contaminants at concentrations in the parts-per-million range. Its capabilities were demonstrated in an experiment aboard the National Aeronautics and Space Administration's Space Shuttle Flight STS-95. This paper describes a modified nonlinear least-squares based algorithm developed to analyze data taken by the ENose, and its performance for the identification and quantification of single gases and binary mixtures of twelve target analytes in clean air. Results from laboratory-controlled events demonstrate the effectiveness of the algorithm to identify and quantify a gas event if concentration exceeds the ENose detection threshold. Results from the flight test demonstrate that the algorithm correctly identifies and quantifies all registered events (planned or unplanned, as singles or mixtures) with no false positives and no inconsistencies with the logged events and the independent analysis of air samples.

Modeling CO2 mass transfer in amine mixtures: PZ-AMP and PZ-MDEA.

PubMed

Puxty, Graeme; Rowland, Robert

2011-03-15

The most common method of carbon dioxide (CO(2)) capture is the absorption of CO(2) into a falling thin film of an aqueous amine solution. Modeling of mass transfer during CO(2) absorption is an important way to gain insight and understanding about the underlying processes that are occurring. In this work a new software tool has been used to model CO(2) absorption into aqueous piperazine (PZ) and binary mixtures of PZ with 2-amino-2-methyl-1-propanol (AMP) or methyldiethanolamine (MDEA). The tool solves partial differential and simultaneous equations describing diffusion and chemical reaction automatically derived from reactions written using chemical notation. It has been demonstrated that by using reactions that are chemically plausible the mass transfer in binary mixtures can be fully described by combining the chemical reactions and their associated parameters determined for single amines. The observed enhanced mass transfer in binary mixtures can be explained through chemical interactions occurring in the mixture without need to resort to using additional reactions or unusual transport phenomena such as the "shuttle mechanism".

Microlayered flow structure around an acoustically levitated droplet under a phase-change process.

PubMed

Hasegawa, Koji; Abe, Yutaka; Goda, Atsushi

2016-01-01

The acoustic levitation method (ALM) has found extensive applications in the fields of materials science, analytical chemistry, and biomedicine. This paper describes an experimental investigation of a levitated droplet in a 19.4-kHz single-axis acoustic levitator. We used water, ethanol, water/ethanol mixture, and hexane as test samples to investigate the effect of saturated vapor pressure on the flow field and evaporation process using a high-speed camera. In the case of ethanol, water/ethanol mixtures with initial ethanol fractions of 50 and 70 wt%, and hexane droplets, microlayered toroidal vortexes are generated in the vicinity of the droplet interface. Experimental results indicate the presence of two stages in the evaporation process of ethanol and binary mixture droplets for ethanol content >10%. The internal and external flow fields of the acoustically levitated droplet of pure and binary mixtures are clearly observed. The binary mixture of the levitated droplet shows the interaction between the configurations of the internal and external flow fields of the droplet and the concentration of the volatile fluid. Our findings can contribute to the further development of existing theoretical prediction.

The Phase Behavior of γ-Oryzanol and β-Sitosterol in Edible Oil.

PubMed

Sawalha, Hassan; Venema, Paul; Bot, Arjen; Flöter, Eckhard; Adel, Ruud den; van der Linden, Erik

The phase behavior of binary mixtures of γ-oryzanol and β-sitosterol and ternary mixtures of γ-oryzanol and β-sitosterol in sunflower oil was studied. Binary mixtures of γ-oryzanol and β-sitosterol show double-eutectic behavior. Complex phase behavior with two intermediate mixed solid phases was derived from differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) data, in which a compound that consists of γ-oryzanol and β-sitosterol molecules at a specific ratio can be formed. SAXS shows that the organization of γ-oryzanol and β-sitosterol in the mixed phases is different from the structure of tubules in ternary systems. Ternary mixtures including sunflower oil do not show a sudden structural transition from the compound to a tubule, but a gradual transition occurs as γ-oryzanol and β-sitosterol are diluted in edible oil. The same behavior is observed when melting binary mixtures of γ-oryzanol and β-sitosterol at higher temperatures. This indicates the feasibility of having an organogelling agent in dynamic exchange between solid and liquid phase, which is an essential feature of triglyceride networks.

Molecular Dynamics Simulation Study of the Capacitive Performance of a Binary Mixture of Ionic Liquids near an Onion-like Carbon Electrode.

PubMed

Li, Song; Feng, Guang; Fulvio, Pasquale F; Hillesheim, Patrick C; Liao, Chen; Dai, Sheng; Cummings, Peter T

2012-09-06

An equimolar mixture of 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C3mpy][Tf2N]), 1-methyl-1-butylpiperidinium bis(trifluoromethylsulfonyl)imide ([C4mpip][Tf2N]) was investigated by classic molecular dynamics (MD) simulation. Differential scanning calorimetry (DSC) measurements verified that the binary mixture exhibited lower glass transition temperature than either of the pure room-temperature ionic liquids (RTILs). Moreover, the binary mixture gave rise to higher conductivity than the neat RTILs at lower temperature range. In order to study its capacitive performance in supercapacitors, simulations were performed of the mixture, and the neat RTILs used as electrolytes near an onion-like carbon (OLC) electrode at varying temperatures. The differential capacitance exhibited independence of the electrical potential applied for three electrolytes, which is in agreement with previous work on OLC electrodes in a different RTILs. Positive temperature dependence of the differential capacitance was observed, and it was dominated by the electrical double layer (EDL) thickness, which is for the first time substantiated in MD simulation.

Mesoscale Polymer Dissolution Probed by Raman Spectroscopy and Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Tsun-Mei; Xantheas, Sotiris S.; Vasdekis, Andreas E.

2016-10-13

The diffusion of various solvents into a polystyrene (PS) matrix was probed experimentally by monitoring the temporal profiles of the Raman spectra and theoretically from molecular dynamics (MD) simulations of the binary system. The simulation results assist in providing a fundamental, molecular level connection between the mixing/dissolution processes and the difference = solvent – PS in the values of the Hildebrand parameter () between the two components of the binary systems: solvents having similar values of with PS (small ) exhibit fast diffusion into the polymer matrix, whereas the diffusion slows down considerably when the ’s are different (large ).more » To this end, the Hildebrand parameter was identified as a useful descriptor that governs the process of mixing in polymer – solvent binary systems. The experiments also provide insight into further refinements of the models specific to non-Fickian diffusion phenomena that need to be used in the simulations.« less

Shear viscosity of binary mixtures: The Gay-Berne potential

NASA Astrophysics Data System (ADS)

Khordad, R.

2012-05-01

The Gay-Berne (GB) potential model is an interesting and useful model to study the real systems. Using the potential model, we intend to examine the thermodynamical properties of some anisotropic binary mixtures in two different phases, liquid and gas. For this purpose, we apply the integral equation method and solve numerically the Percus-Yevick (PY) integral equation. Then, we obtain the expansion coefficients of correlation functions to calculate the thermodynamical properties. Finally, we compare our results with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, benzene + methanol, cyclohexane + ethanol, benzene + ethanol, carbon tetrachloride + ethyl acetate, and methanol + ethanol]. The results show that the GB potential model is capable for predicting the thermodynamical properties of binary mixtures with acceptable accuracy.

Thermal phase diagram of acetamide-benzoic acid and benzoic acid-phthalimide binary systems for solar thermal applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Rohitash, E-mail: dootrohit1976@gmail.com; Department of Physics & Center for Solar Energy, Indian Institute of Technology Jodhpur, Rajasthan, India 342011, +91-291-2449045; Kumar, Ravindra

2016-05-06

Thermal properties of Acetamide (AM) – Benzoic acid (BA) and Benzoic acid (BA) – Phthalimide (PM) binary eutectic systems are theoretically calculated using thermodynamic principles. We found that the binary systems of AM-BA at 67.6 : 32.4 molar ratio, BA-PM at 89.7 : 10.3 molar ratio form eutectic mixtures with melting temperatures ~ 54.5 °C and 114.3 °C respectively. Calculated latent heat of fusion for these eutectic mixtures are 191 kJ/kg and 146.5 kJ/kg respectively. These melting temperatures and heat of fusions of these eutectic mixtures make them suitable for thermal energy storage applications in solar water heating and solarmore » cooking systems.« less

Study of molecular interactions in binary mixtures of 2-chloro-4'methoxy benzoin with various solvents through ultrasonic speed measurements

NASA Astrophysics Data System (ADS)

Thanuja, B.; Kanakam, C.; Nithya, G.

2013-12-01

Density ( ρ) and ultrasonic velocity ( U), for binary mixtures of 2-chloro-4'-methoxy benzoin with ethanol, chloroform, acetonitrile, benzene and 1,4-dioxane of different compositions have been measured at 298 K and explanation of solute solvent interactions and effect of polarity of the solvent on type of interactions are presented in this paper. From the above data, adiabatic compressibility ( β), intermolecular free length ( L f ) and relative association ( R A ) have been calculated. Other useful parameters such as excess density, excess velocity, excess intermolecular freelength and excess adiabatic compressibility have also been calculated. These parameters have been used to study the nature and extent of intermolecular interactions between component molecules in present binary mixtures.

Thermodynamic Parameters of Cholesteric/Smectic A Transition in Cholesteric Myristate and Its Binary Mixture CM/PCPB

NASA Astrophysics Data System (ADS)

Yurtseven, H.; Dogan, E. Kilit

2018-06-01

Thermodynamic properties of the cholesteryl myristate (CM) and its binary mixture CM/PCPB ( p-pentylphenyl-2-chloro-4( p-pentylbenzoyl)-benzoate) are studied at the concentrations of x PCPB = 0.052 and 0.219 as a function of temperature near the cholosteric/smectic A transition. By analyzing the observed molar volume from the literature, the temperature dependences of the thermal expansion, isothermal compressibility and the difference in the specific heat are calculated and, the Pippard relations are established for those compounds close to the cholesteric/smectic A transition. Predictions of the thermodynamic quantities and the Pippard relations can be examined by the experimental measurements of the CM and its binary mixture of CM/PCPB close to the cholesteric/smectic A transition.

Uniform phases in fluids of hard isosceles triangles: One-component fluid and binary mixtures

NASA Astrophysics Data System (ADS)

Martínez-Ratón, Yuri; Díaz-De Armas, Ariel; Velasco, Enrique

2018-05-01

We formulate the scaled particle theory for a general mixture of hard isosceles triangles and calculate different phase diagrams for the one-component fluid and for certain binary mixtures. The fluid of hard triangles exhibits a complex phase behavior: (i) the presence of a triatic phase with sixfold symmetry, (ii) the isotropic-uniaxial nematic transition is of first order for certain ranges of aspect ratios, and (iii) the one-component system exhibits nematic-nematic transitions ending in critical points. We found the triatic phase to be stable not only for equilateral triangles but also for triangles of similar aspect ratios. We focus the study of binary mixtures on the case of symmetric mixtures: equal particle areas with aspect ratios (κi) symmetric with respect to the equilateral one, κ1κ2=3 . For these mixtures we found, aside from first-order isotropic-nematic and nematic-nematic transitions (the latter ending in a critical point): (i) a region of triatic phase stability even for mixtures made of particles that do not form this phase at the one-component limit, and (ii) the presence of a Landau point at which two triatic-nematic first-order transitions and a nematic-nematic demixing transition coalesce. This phase behavior is analogous to that of a symmetric three-dimensional mixture of rods and plates.

Binary Polymer Brushes of Strongly Immiscible Polymers.

PubMed

Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

2015-06-17

The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

Kirkwood–Buff integrals for ideal solutions

PubMed Central

Ploetz, Elizabeth A.; Bentenitis, Nikolaos; Smith, Paul E.

2010-01-01

The Kirkwood–Buff (KB) theory of solutions is a rigorous theory of solution mixtures which relates the molecular distributions between the solution components to the thermodynamic properties of the mixture. Ideal solutions represent a useful reference for understanding the properties of real solutions. Here, we derive expressions for the KB integrals, the central components of KB theory, in ideal solutions of any number of components corresponding to the three main concentration scales. The results are illustrated by use of molecular dynamics simulations for two binary solutions mixtures, benzene with toluene, and methanethiol with dimethylsulfide, which closely approach ideal behavior, and a binary mixture of benzene and methanol which is nonideal. Simulations of a quaternary mixture containing benzene, toluene, methanethiol, and dimethylsulfide suggest this system displays ideal behavior and that ideal behavior is not limited to mixtures containing a small number of components. PMID:20441282

Silo discharge of binary granular mixtures.

PubMed

Madrid, M; Asencio, K; Maza, D

2017-08-01

We present numerical and experimental results on the mass flow rate during the discharge of three-dimensional silos filled with a bidisperse mixture of grains of different sizes. We analyzed the influence of the ratio between coarse and fine particles on the profile of volume fraction and velocity across the orifice. By using numerical simulations, we have shown that the velocity profile has the same shape as that in the monodisperse case and is insensitive to the composition of the mixture. On the contrary, the volume fraction profile is strongly affected by the composition of the mixture. Assuming that an effective particle size can be introduced to characterize the mixture, we have shown that previous expression for the mass flow rate of monodisperse particles can be used for binary mixtures. A comparison with Beverloo's correlation is also presented.

Coal liquefaction process using pretreatment with a binary solvent mixture

DOEpatents

Miller, R.N.

1986-10-14

An improved process for thermal solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprises pretreating the coal with a binary mixture of an aromatic hydrocarbon and an aliphatic alcohol at a temperature below 300 C before the hydroliquefaction step. This treatment generally increases both conversion of coal and yields of oil. 1 fig.

Coal liquefaction process using pretreatment with a binary solvent mixture

DOEpatents

Miller, Robert N.

1986-01-01

An improved process for thermal solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprises pretreating the coal with a binary mixture of an aromatic hydrocarbon and an aliphatic alcohol at a temperature below 300.degree. C. before the hydroliquefaction step. This treatment generally increases both conversion of coal and yields of oil.

Composition measurements of binary mixture droplets by rainbow refractometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilms, J.; Weigand, B

2007-04-10

So far, refractive index measurements by rainbow refractometry have been used to determine the temperature of single droplets and ensembles of droplets. Rainbow refractometry is, for the first time, to the best of our knowledge, applied to measure composition histories of evaporating, binary mixture droplets. An evaluation method is presented that makes use of Airy theory and the simultaneous size measurement by Mie scattering imaging. The method further includes an empirical correction function for a certain diameter and refractive index range. The measurement uncertainty was investigated by numerical simulations with Lorenz-Mie theory. For the experiments, an optical levitation setup wasmore » used allowing for long measurement periods. Temperature measurements of single-component droplets at different temperature levels are shown to demonstrate the accuracy of rainbow refractometry. Measurements of size and composition histories of binary mixture droplets are presented for two different mixtures. Experimental results show good agreement with numerical results using a rapid-mixing model.« less

Individual and binary mixture effects of bisphenol A and lignin-derived bisphenol in Daphnia magna under chronic exposure.

PubMed

Li, Dan; Chen, Hongxing; Bi, Ran; Xie, Haibo; Zhou, Yu; Luo, Yongju; Xie, Lingtian

2018-01-01

In recent years, many new chemicals have been synthesized from biomass with an aim for sustainable development by replacing the existing toxic chemicals with those having similar properties and applications. However, the effects of these new chemicals on aquatic organisms remain relatively unknown. In this study, the effects of bisphenol A (BPA) and lignin-derived bisphenol (LD-BP, a BPA analogue) on Daphnia magna were evaluated. The animals were exposed to BPA, LD-BP, and their binary mixture at concentrations (2-2000 μg L -1 ) for 21 days. The expression of various biochemical markers and the effects on growth, molting, and reproduction parameters were examined. The results showed that the weight of daphnids significantly increased after exposure to BPA, LD-BP, and the binary mixture relative to that of the control animals. The activity of superoxide dismutase was significantly inhibited by LD-BP and the binary mixture. At the highest exposure concentration of the binary mixture, the activities of acetylcholinesterase and α-glucosidase, fecundity, and the number of neonates per brood were significantly altered. Our results showed that the effects of BPA and LD-BP on D. magna were generally comparable, except for the effect on the weight at their environmentally relevant concentrations (e.g., <20 μg L -1 ). The effects on the reproduction of D. magna could be mainly due to the shift in energy redistribution under BPA and LD-BP exposures. Our results implied that exposures to both BPA and LD-BP could potentially cause deleterious effects at the population level in D. magna. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method for retorting oil shale

DOEpatents

Shang, Jer-Yu; Lui, A.P.

1985-08-16

The recovery of oil from oil shale is provided in a fluidized bed by using a fluidizing medium of a binary mixture of carbon dioxide and 5 steam. The mixture with a steam concentration in the range of about 20 to 75 volume percent steam provides an increase in oil yield over that achievable by using a fluidizing gas of carbon dioxide or steam alone when the mixture contains higher steam concentrations. The operating parameters for the fluidized bed retorted are essentially the same as those utilized with other gaseous fluidizing mediums with the significant gain being in the oil yield recovered which is attributable solely to the use of the binary mixture of carbon dioxide and steam. 2 figs.

Heterogeneous structure and solvation dynamics of DME/water binary mixtures: A combined spectroscopic and simulation investigation

NASA Astrophysics Data System (ADS)

Das Mahanta, Debasish; Rana, Debkumar; Patra, Animesh; Mukherjee, Biswaroop; Mitra, Rajib Kumar

2018-05-01

Water is often found in (micro)-heterogeneous environments and therefore it is necessary to understand their H-bonded network structure in such altered environments. We explore the structure and dynamics of water in its binary mixture with relatively less polar small biocompatible amphiphilic molecule 1,2-Dimethoxyethane (DME) by a combined spectroscopic and molecular dynamics (MD) simulation study. Picosecond (ps) resolved fluorescence spectroscopy using coumarin 500 as the fluorophore establishes a non-monotonic behaviour of the mixture. Simulation studies also explore the various possible H-bond formations between water and DME. The relative abundance of such different water species manifests the heterogeneity in the mixture.

Carbon dioxide-soluble polymers and swellable polymers for carbon dioxide applications

DOEpatents

DeSimone, Joseph M.; Birnbaum, Eva; Carbonell, Ruben G.; Crette, Stephanie; McClain, James B.; McCleskey, T. Mark; Powell, Kimberly R.; Romack, Timothy J.; Tumas, William

2004-06-08

A method for carrying out a catalysis reaction in carbon dioxide comprising contacting a fluid mixture with a catalyst bound to a polymer, the fluid mixture comprising at least one reactant and carbon dioxide, wherein the reactant interacts with the catalyst to form a reaction product. A composition of matter comprises carbon dioxide and a polymer and a reactant present in the carbon dioxide. The polymer has bound thereto a catalyst at a plurality of chains along the length of the polymer, and wherein the reactant interacts with the catalyst to form a reaction product.

Viscosity and thermal conductivity of moderately dense gas mixtures.

NASA Technical Reports Server (NTRS)

Wakeham, W. A.; Kestin, J.; Mason, E. A.; Sandler, S. I.

1972-01-01

Derivation of a simple, semitheoretical expression for the initial density dependence of the viscosity and thermal conductivity of gaseous mixtures in terms of the appropriate properties of the pure components and of their interaction quantities. The derivation is based on Enskog's theory of dense gases and yields an equation in which the composition dependence of the linear factor in the density expansion is explicit. The interaction quantities are directly related to those of the mixture extrapolated to zero density and to a universal function valid for all gases. The reliability of the formulation is assessed with respect to the viscosity of several binary mixtures. It is found that the calculated viscosities of binary mixtures agree with the experimental data with a precision which is comparable to that of the most precise measurements.

Influence of the Kinetics of Heat and Mass Transfer in a Binary-Rectification Column on the Realizability Range of its Regimes

NASA Astrophysics Data System (ADS)

Zaeva, M. A.; Tsirlin, A. M.; Sukin, I. A.

2018-05-01

The range of realizable rates of flows in a binary-rectification column in which heat is supplied into the boiler and is removed from the dephlegmator was investigated. It is shown that this range is determined by two characteristic parameters related to the kinetics of heat and mass transfer in the column and the composition of the mixture subjected to separation. The limiting capabilities of a cascade of two binary-rectification columns for the separation of a ternary mixture in it were considered. The conditions for an optimum sequence of separation of a mixture in this cascade and for a consistent arrangement of its heat and mass exchange surfaces and the relation between the ultimate production rate of the cascade and the total heat losses in it were determined.

Influence of the Kinetics of Heat and Mass Transfer in a Binary-Rectification Column on the Realizability Range of its Regimes

NASA Astrophysics Data System (ADS)

Zaeva, M. A.; Tsirlin, A. M.; Sukin, I. A.

2018-03-01

The range of realizable rates of flows in a binary-rectification column in which heat is supplied into the boiler and is removed from the dephlegmator was investigated. It is shown that this range is determined by two characteristic parameters related to the kinetics of heat and mass transfer in the column and the composition of the mixture subjected to separation. The limiting capabilities of a cascade of two binary-rectification columns for the separation of a ternary mixture in it were considered. The conditions for an optimum sequence of separation of a mixture in this cascade and for a consistent arrangement of its heat and mass exchange surfaces and the relation between the ultimate production rate of the cascade and the total heat losses in it were determined.

Mixing and demixing of binary mixtures of polar chiral active particles.

PubMed

Ai, Bao-Quan; Shao, Zhi-Gang; Zhong, Wei-Rong

2018-05-17

We study a binary mixture of polar chiral (counterclockwise or clockwise) active particles in a two-dimensional box with periodic boundary conditions. Besides the excluded volume interactions between particles, the particles are also subjected to the polar velocity alignment. From the extensive Brownian dynamics simulations, it is found that the particle configuration (mixing or demixing) is determined by the competition between the chirality difference and the polar velocity alignment. When the chirality difference competes with the polar velocity alignment, the clockwise particles aggregate in one cluster and the counterclockwise particles aggregate in the other cluster; thus, the particles are demixed and can be separated. However, when the chirality difference or the polar velocity alignment is dominant, the particles are mixed. Our findings could be used for the experimental pursuit of the separation of binary mixtures of chiral active particles.

Ultrasonic studies of intermolecular interactions in binary mixtures of 4-methoxy benzoin with various solvents: Excess molar functions of ultrasonic parameters at different concentrations and in different solvents.

PubMed

Thanuja, B; Nithya, G; Kanagam, Charles C

2012-11-01

Density (ρ), ultrasonic velocity (U), for the binary mixtures of 4-methoxy benzoin (4MB) with ethanol, chloroform, acetonitrile, benzene, and di-oxane were measured at 298K. The solute-solvent interactions and the effect of the polarity of the solvent on the type of intermolecular interactions are discussed here. From the above data, adiabatic compressibility (β), intermolecular free length (L(f)), acoustic impedance (Z), apparent molar volume (Ø), relative association (RA) have been calculated. Other useful parameters such as excess density, excess velocity and excess adiabatic compressibility have also been calculated. These parameters were used to study the nature and extent of intermolecular interactions between component molecules in the binary mixtures. Copyright © 2012 Elsevier B.V. All rights reserved.

.pi.-conjugated heavy-metal polymers for organic white-light-emitting diodes

DOEpatents

Vardeny, Zeev Valentine; Wojcik, Leonard; Drori, Tomer

2016-09-13

A polymer mixture emits a broad spectrum of visible light that appears white or near-white in the aggregate. The polymer mixture comprises two (or more) components in the active layer. A heavy atom, such as platinum and/or iridium, present in the backbone of the mixture acts via a spin-orbit coupling mechanism to cause the ratio of fluorescent to phosphorescent light emission bands to be of approximately equal strength. These two broad emissions overlap, resulting in an emission spectrum that appears to the eye to be white.

Method of Preparing Polymers with Low Melt Viscosity

NASA Technical Reports Server (NTRS)

Jensen, Brian J. (Inventor)

2001-01-01

This invention is an improvement in standard polymerizations procedures, i.e., addition-type and step-growth type polymerizations, wherein monomers are reacted to form a growing polymer chain. The improvement includes employing an effective amount of a trifunctional monomer (such as a trifunctional amine anhydride, or phenol) in the polymerization procedure to form a mixture of polymeric materials consisting of branced polymers, star-shaped polymers, and linear polymers. This mixture of polymeric materials has a lower melt temperature and a lower melt viscosity than corresponding linear polymeric materials of equivalent molecular weight.

Multisubstrate biodegradation kinetics of naphthalene, phenanthrene, and pyrene mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guha, S.; Peters, C.A.; Jaffe, P.R.

Biodegradation kinetics of naphthalene, phenanthrene and pyrene were studied in sole-substrate systems, and in binary and ternary mixtures to examine substrate interactions. The experiments were conducted in aerobic batch aqueous systems inoculated with a mixed culture that had been isolated from soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Monod kinetic parameters and yield coefficients for the individual parameters and yield coefficients for the individual compounds were estimated from substrate depletion and CO{sub 2} evolution rate data in sole-substrate experiments. In all three binary mixture experiments, biodegradation kinetics were comparable to the sole-substrate kinetics. In the ternary mixture, biodegradation of naphthalenemore » was inhibited and the biodegradation rates of phenanthrene and pyrene were enhanced. A multisubstrate form of the Monod kinetic model was found to adequately predict substrate interactions in the binary and ternary mixtures using only the parameters derived from sole-substrate experiments. Numerical simulations of biomass growth kinetics explain the observed range of behaviors in PAH mixtures. In general, the biodegradation rates of the more degradable and abundant compounds are reduced due to competitive inhibition, but enhanced biodegradation of the more recalcitrant PAHs occurs due to simultaneous biomass growth on multiple substrates. In PAH-contaminated environments, substrate interactions may be very large due to additive effects from the large number of compounds present.« less

Properties of L-ascorbic acid in water and binary aqueous mixtures of D-glucose and D-fructose at different temperatures

NASA Astrophysics Data System (ADS)

Sharma, Ravi; Thakur, R. C.; Sani, Balwinder; Kumar, Harsh

2017-12-01

Using density and sound velocity partial molar volumes, partial molar adiabatic compressibilities, partial molar expansibilities and structure of L-ascorbic acid have been determined in water and aqueous mixtures of D-glucose and D-fructose at different concentrations and temperatures. Masson's equation was used to analyze the measured data. The obtained parameters have been interpreted in terms of solute-solute and solute-solvent interactions. It is found that the L-ascorbic acid acts as structure breaker in water as well in binary studied mixtures.

Rheological characterizations of concentrated binary gum mixtures with xanthan gum and galactomannans.

PubMed

Jo, Wonjun; Bak, June Ha; Yoo, Byoungseung

2018-03-20

The steady and dynamic shear rheological properties of binary gum mixtures with xanthan gum (XG) and galactomannans (guar gum (GG) and locust bean gum (LBG)) were examined in a concentrated solution (1% w/w) as a function of gum mixing ratio (100/0, 75/25, 50/50, and 0/100). All samples, except for individual GG and LBG, showed high shear-thinning behavior with yield stress. The values of flow (K, η a,50 , and σ oc ) and dynamic rheological parameters (G' and G″) of XG-GG and XG-LBG mixtures were significantly higher compared to XG alone, indicating that the flow and viscoelastic properties of binary gum mixtures were greatly affected by the addition of GG and LBG. The maximum elasticity synergistic interaction for XG-galactomannans mixtures was observed at a mixing ratio of 50/50, showing a greatly positive deviation between measured and calculated values of G'. These results suggest that the synergistic effect of GG and LBG addition on rheological properties of XG appears to be due to intermolecular interaction occurred between XG and galactomannans, as confirmed by dynamic rheological properties. Copyright © 2018 Elsevier B.V. All rights reserved.

Microlayered flow structure around an acoustically levitated droplet under a phase-change process

PubMed Central

Hasegawa, Koji; Abe, Yutaka; Goda, Atsushi

2016-01-01

The acoustic levitation method (ALM) has found extensive applications in the fields of materials science, analytical chemistry, and biomedicine. This paper describes an experimental investigation of a levitated droplet in a 19.4-kHz single-axis acoustic levitator. We used water, ethanol, water/ethanol mixture, and hexane as test samples to investigate the effect of saturated vapor pressure on the flow field and evaporation process using a high-speed camera. In the case of ethanol, water/ethanol mixtures with initial ethanol fractions of 50 and 70 wt%, and hexane droplets, microlayered toroidal vortexes are generated in the vicinity of the droplet interface. Experimental results indicate the presence of two stages in the evaporation process of ethanol and binary mixture droplets for ethanol content >10%. The internal and external flow fields of the acoustically levitated droplet of pure and binary mixtures are clearly observed. The binary mixture of the levitated droplet shows the interaction between the configurations of the internal and external flow fields of the droplet and the concentration of the volatile fluid. Our findings can contribute to the further development of existing theoretical prediction. PMID:28725723

Redox States of Initial Atmospheres Outgassed on Rocky Planets and Planetesimals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Laura; Fegley, Bruce Jr., E-mail: lschaefer@asu.edu

2017-07-10

The Earth and other rocky planets and planetesimals in the solar system formed through the mixing of materials from various radial locations in the solar nebula. This primordial material likely had a range of oxidation states as well as bulk compositions and volatile abundances. We investigate the oxygen fugacity produced by the outgassing of mixtures of solid meteoritic material, which approximate the primitive nebular materials. We find that the gas composition and oxygen fugacity of binary and ternary mixtures of meteoritic materials vary depending on the proportion of reduced versus oxidized material, and also find that mixtures using differentiated materialsmore » do not show the same oxygen fugacity trends as those using similarly reduced but undifferentiated materials. We also find that simply mixing the gases produced by individual meteoritic materials together does not correctly reproduce the gas composition or oxygen fugacity of the binary and ternary mixtures. We provide tabulated fits for the oxygen fugacities of all of the individual materials and binary mixtures that we investigate. These values may be useful in planetary formation models, models of volatile transport on planetesimals or meteorite parent bodies, or models of trace element partitioning during metal-silicate fractionation.« less

Removal of phenol from aqueous solution using polymer inclusion membrane based on mixture of CTA and CA

NASA Astrophysics Data System (ADS)

Benosmane, Nadjib; Boutemeur, Baya; Hamdi, Safouane M.; Hamdi, Maamar

2018-03-01

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. In the present work, the removal of phenol from aqueous solution across polymer inclusion membrane (PIM), based on mixture of cellulose triacetate and cellulose acetate as support (75/25%), calix[4]resorcinarene derivative as a carrier and 2-nitrophenyl octyl ether (2-NPOE) as plasticizer was investigated. The experimental part of this investigation involved the influence of carrier nature, plasticizer concentration, pH phases, and phenol initial concentration on the removal efficiency of phenol from synthetic wastewater. A PIM containing 0.1 g (of mixture polymer), (0.15 g/g mixture of polymer) of carrier and (0.03 ml/g mixture of polymer) of 2-NPOE provided the highest percentage of phenol removal efficiency over a 6-day transport; the removal was found to be about 95%, indeed the removal was found to be highly dependent of pH phases. The feed solution in these transport experiments was at pH 2, while the stripping solution contained 0.20 M NaOH. This study claims that the PIM with a mixture of cellulose derivatives can be used effectively to remove phenols from wastewaters.

Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids.

PubMed

Finotello, Alexia; Bara, Jason E; Narayan, Suguna; Camper, Dean; Noble, Richard D

2008-02-28

This study focuses on the solubility behaviors of CO2, CH4, and N2 gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) at 40 degrees C and low pressures (approximately 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % [C2mim][BF4] in [C2mim][Tf2N]. Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO2 with N2 or CH4 in pure [C2mim][BF4] can be enhanced by adding 5 mol % [C2mim][Tf2N].

Pervaporative stripping of acetone, butanol and ethanol to improve ABE fermentation.

PubMed

Jitesh, K; Pangarkar, V G; Niranjan, K

2000-01-01

Acetone-butanol-ethanol fermentation by anaerobic bacterium C. acetobutylicum is a potential source for feedstock chemicals. The problem of product induced inhibition makes this fermentation economically infeasible. Pervaporation is studied as an effective separation technique to remove the toxic inhibitory products. Various membranes like Styrene Butadiene Rubber (SBR), Ethylene Propylene Diene Rubber (EPDM), plain Poly Dimethyl Siloxane (PDMS) and silicalite filled PDMS were studied for the removal of acetone, butanol and ethanol, from binary aqueous mixtures and from a quaternary mixture. It was found that the overall performance of PDMS filled with 15% w/w of silicalite was the best for removal of butanol in binary mixture study. SBR performance was best for the quaternary mixture studied.

Transport properties of nonelectrolyte liquid mixtures. VIII. Viscosity coefficients for toluene and for three mixtures of toluene + hexane from 25 to 100°C at pressures up to 500 MPa

NASA Astrophysics Data System (ADS)

Dymond, J. H.; Awan, M. A.; Glen, N. F.; Isdale, J. D.

1991-03-01

Viscosity coefficients measured using a two-coil self-centering falling-body viscometer are reported for toluene and three binary mixtures of toluene + n-hexane at 25, 50, 75, and 100°C at pressures up to 500 MPa. The data for a given composition at different temperatures and pressures are correlated very satisfactorily by a plot of reduced viscosity η * versus log V', where V'= V· V 0(TR)/V0(T) and V 0 represents a characteristic volume. The binary mixture data are well represented by the Grunberg and Nissan equation with a mixing parameter which is pressure dependent but composition and temperature independent.

Dielectric properties of binary mixtures of methyl iso butyl ketone and amino silicone oil

NASA Astrophysics Data System (ADS)

Shah, K. N.; Rana, V. A.; Trivedi, C. M.; Vankar, H. P.

2017-05-01

Dielectric permittivity ɛ*(ω) = ɛ' - jɛ″ of the binary mixtures of the methyl iso butyl ketone and amino silicone oil in the frequency range 100 Hz to 2 MHz were measured using precision LCR meter at 305.15 K. Relative complex permittivity spectra in the frequency range 100 Hz to 2 MHz, of the mixture solutions of varying concentrations is reported. Determined values of the permittivity at optical frequency of all the samples are also reported. The dielectric parameters are used to gain information about the effect of concentration variation of components of the mixtures on the dielectric properties. It also provides the information about electrode polarization phenomena taking place under the low frequency A.C. electric field.

Preferential solvation of lysozyme in dimethyl sulfoxide/water binary mixture probed by terahertz spectroscopy.

PubMed

Das, Dipak Kumar; Patra, Animesh; Mitra, Rajib Kumar

2016-09-01

We report the changes in the hydration dynamics around a model protein hen egg white lysozyme (HEWL) in water-dimethyl sulfoxide (DMSO) binary mixture using THz time domain spectroscopy (TTDS) technique. DMSO molecules get preferentially solvated at the protein surface, as indicated by circular dichroism (CD) and Fourier transform infrared (FTIR) study in the mid-infrared region, resulting in a conformational change in the protein, which consequently modifies the associated hydration dynamics. As a control we also study the collective hydration dynamics of water-DMSO binary mixture and it is found that it follows a non-ideal behavior owing to the formation of DMSO-water clusters. It is observed that the cooperative dynamics of water at the protein surface does follow the DMSO-mediated conformational modulation of the protein. Copyright © 2016 Elsevier B.V. All rights reserved.

Raman bandshape analysis on CH and CSC stretching modes of dimethyl sulfoxide in liquid binary mixture: comparative study with quantum-chemical calculations.

PubMed

Upadhyay, Ganesh; Gomti Devi, Th

2014-12-10

The interacting nature of dimethyl sulfoxide (DMSO) in binary mixtures has been carried out on CH and CSC stretching modes of vibration using chloroform (CLF), chloroform-d (CLFd), acetonitrile (ACN) and acetonitrile-d3 (ACNd) solvents. Peak frequencies of both the stretching modes show blue shift with the increase in solvent concentration. Variation of Raman bandwidth with the solvent concentration was discussed using different mechanisms. Ab initio calculation for geometry optimization and vibrational wavenumber calculation have been performed on monomer and dimer structures of DMSO to explain the experimentally observed Raman spectra. Theoretically calculated values are found in good agreement with the experimental results. Vibrational and reorientational relaxation times have been studied corresponding to solvent concentrations to elucidate the interacting mechanisms of binary mixtures. Copyright © 2014 Elsevier B.V. All rights reserved.

Binary Phase Behavior of Saturated-Unsaturated Mixed-Acid Triacylglycerols-A Review.

PubMed

Zhang, Lu; Ueno, Satoru; Sato, Kiyotaka

2018-06-01

Most natural lipids contain a complex mixture of individual triacylglycerols (TAGs). An in-depth knowledge of the mixing behavior of TAGs is necessary for the rational design and engineering of food materials. The binary phase diagram of TAGs is a simplified model that can be explored to help foster an understanding of the phase behavior of complex fats and oils. This article reviews recent research on the binary phase behavior of saturated-unsaturated mixed-acid TAGs, with special emphasis on the stearicunsaturated and palmitic-unsaturated diacid TAGs. The occurrence of polymorphic forms and mutual solubility of TAG mixtures are strongly related to the glycerol conformation of the saturated-oleic diacid TAGs; it appears to be most influenced by the chain-length mismatch in saturated-elaidic diacid TAGs. In addition, the polymorphism of pure enantiomers and racemic mixture of chiral TAGs was also reviewed, while the effect of chirality on mixing behavior was discussed.

The toxicity of binary mixture of Cu (II) ion and phenols on Tetrahymena thermophila.

PubMed

Luo, Hui; Li, Xi; Fang, Tingting; Liu, Peng; Zhang, Chaocan; Xie, Hao; Sun, Enjie

2015-03-01

The toxicity of binary mixture of Cu(2+) and phenols (phenol; o-nitrophenol; m-nitrophenol; p-nitrophenol) was evaluated using Tetrahymena thermophila as the model organism, by microcalorimetry, optical density, field emission scanning electron microscope (FESEM) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The growth curves and metabolic properties of Tetrahymena exposed to Cu(2+) and phenols were monitored by microcalorimetry. Binary mixture toxicity changed with the concentration of Cu(2+)/phenols and the order of toxicity was Cu(2+)/phenol

Comparative study on the selectivity of various spectrophotometric techniques for the determination of binary mixture of fenbendazole and rafoxanide.

PubMed

Saad, Ahmed S; Attia, Ali K; Alaraki, Manal S; Elzanfaly, Eman S

2015-11-05

Five different spectrophotometric methods were applied for simultaneous determination of fenbendazole and rafoxanide in their binary mixture; namely first derivative, derivative ratio, ratio difference, dual wavelength and H-point standard addition spectrophotometric methods. Different factors affecting each of the applied spectrophotometric methods were studied and the selectivity of the applied methods was compared. The applied methods were validated as per the ICH guidelines and good accuracy; specificity and precision were proven within the concentration range of 5-50 μg/mL for both drugs. Statistical analysis using one-way ANOVA proved no significant differences among the proposed methods for the determination of the two drugs. The proposed methods successfully determined both drugs in laboratory prepared and commercially available binary mixtures, and were found applicable for the routine analysis in quality control laboratories. Copyright © 2015 Elsevier B.V. All rights reserved.

Study of complex permittivity spectra of binary mixtures of 2-chloroaniline and methanol in frequency range 10 KHz to 2 MHz at different temperatures

NASA Astrophysics Data System (ADS)

Shah, N. S.; Vankar, H. P.; Rana, V. A.

2017-05-01

The complex relative dielectric function ɛ*(ω)=ɛ'-jɛ″ of the binary mixture of 2-chloroaniline(2-CA) and methanol (MeOH) were measured using precision LCR meter in the frequency range of 10 KHz to 2 MHz The measurements were carried out at eight different temperatures and five different concentrations of 2-CA and MeOH. The loss tangent peaks were observed in the studied frequency range for all the binary mixtures. From the loss tangent peaks electrode polarization relaxation time were evaluated. In the plot of real part of complex permittivity against frequency, at different temperatures for 2-CA (54.54%) + MeOH (45.45%) and 2-CA (27.27%) + MeOH (72.72%)and 100% MeOH systems permittivity inversion effect was observed.

Study of intermolecular interactions in binary mixtures of 2'-chloro-4-methoxy-3-nitro benzil in various solvents and at different concentrations by the measurement of acoustic properties.

PubMed

Nithya, G; Thanuja, B; Kanagam, Charles C

2013-01-01

Density (ρ), ultrasonic velocity (u), adiabatic compressibility (β), apparent molar volume (Ø), acoustic impedance (Z), intermolecular free length (L(f)), relative association (RA) of binary mixtures of 2'-chloro-4-methoxy-3-nitro benzil (abbreviated as 2CBe) in ethanol, acetonitrile, chloroform, dioxane and benzene were measured at different concentrations at 298 K. Several useful parameters such as excess density, excess ultrasonic velocity, excess adiabatic compressibility, excess apparent molar volume, excess acoustic impedance and excess intermolecular free length have been calculated. These parameters are used to explain the nature of intermolecular interactions taking place in the binary mixture. The above study is useful in understanding the solute--solvent interactions occurring in different concentrations at room temperature. Copyright © 2012 Elsevier B.V. All rights reserved.

Spectroscopic and Chemometric Analysis of Binary and Ternary Edible Oil Mixtures: Qualitative and Quantitative Study.

PubMed

Jović, Ozren; Smolić, Tomislav; Primožič, Ines; Hrenar, Tomica

2016-04-19

The aim of this study was to investigate the feasibility of FTIR-ATR spectroscopy coupled with the multivariate numerical methodology for qualitative and quantitative analysis of binary and ternary edible oil mixtures. Four pure oils (extra virgin olive oil, high oleic sunflower oil, rapeseed oil, and sunflower oil), as well as their 54 binary and 108 ternary mixtures, were analyzed using FTIR-ATR spectroscopy in combination with principal component and discriminant analysis, partial least-squares, and principal component regression. It was found that the composition of all 166 samples can be excellently represented using only the first three principal components describing 98.29% of total variance in the selected spectral range (3035-2989, 1170-1140, 1120-1100, 1093-1047, and 930-890 cm(-1)). Factor scores in 3D space spanned by these three principal components form a tetrahedral-like arrangement: pure oils being at the vertices, binary mixtures at the edges, and ternary mixtures on the faces of a tetrahedron. To confirm the validity of results, we applied several cross-validation methods. Quantitative analysis was performed by minimization of root-mean-square error of cross-validation values regarding the spectral range, derivative order, and choice of method (partial least-squares or principal component regression), which resulted in excellent predictions for test sets (R(2) > 0.99 in all cases). Additionally, experimentally more demanding gas chromatography analysis of fatty acid content was carried out for all specimens, confirming the results obtained by FTIR-ATR coupled with principal component analysis. However, FTIR-ATR provided a considerably better model for prediction of mixture composition than gas chromatography, especially for high oleic sunflower oil.

Small Angle Neutron Scattering Study in Multi-Component Polymer Systems: Spinodal Decomposition and Beyond

NASA Astrophysics Data System (ADS)

Han, Charles

Institute for Advanced Study, Shenzhen University, Shenzhen, China In memory of Professor John Kohn at this symposium, a time resolved SANS study for the early stage of spinodal decomposition kinetics of deuterated polycarbonate/poly(methylmethacrylate) blend will be reviewed which gives a clear proof of the Cahn-Hillard-Cook theory. This early stage of spinodal decomposition kinetics has been observed starting from the dimension (q-l) comparable to the single chain radius of gyration, Rg\\ , for a binary polymer mixture. The results provide an unequivocal quantitative measure of the virtual structure factor, S (q, ∞); the relationship of qm and qc through rate of growth, Cahn-plot analysis, and singularity in S (q, ∞); the growth of fluctuation of qRg <1 and intra-chain relaxation of qRg >1. More recent study of using mixed suspensions of polystyrene microspheres and poly(N-isopropylacrylamide) microgels as a molecular model system which has a long range repulsive interaction potential and a short range attractive potential, will also be discussed. In this model system, dynamic gelation, transition to soft glass state and cross-over to hard glass state will be demonstrated and compared with available theories for glass transition in structural materials. Acknowledgements go to: Polymers Division, and NCNR of NIST, and to ICCAS, Beijing, China. Also to my colleagues: M. Motowoka, H. Jinnai, T. Hashimoto, G.C. Yuan and H. Cheng.

Self-standing gel polymer electrolyte for improving supercapacitor thermal and electrochemical stability

NASA Astrophysics Data System (ADS)

Dagousset, Laure; Pognon, Grégory; Nguyen, Giao T. M.; Vidal, Frédéric; Jus, Sébastien; Aubert, Pierre-Henri

2018-07-01

Electrochemical energy storage is a very active research topic. However, the use of liquid electrolyte in such systems as supercacitors presents several drawbacks on security and packaging. One way to overcome these issues is to design supercapacitors using solid-state electrolytes. We report here the one-pot synthesis and the characterization of self-standing gel polymer electrolyte (SGPE) composed of semi-Interpenetrating Polymer Networks (semi-IPN) based on poly(ethylene oxide) (PEO) network and non cross-linked nitrile butadiene rubber (NBR), self-containing EMITFSI/γ-Butyrolactone (50/50 wt%/wt%) binary mixtures. The SGPE under the form of a thin film are then used as solid electrolyte and also as separator in supercapacitors with Single Wall Carbon Nanotubes (SWCNTs) bucky paper as electrodes. Thermal characterization revealed the suitability of all synthesized membrane in wide range of operating temperature. Electrochemical stabilities of SGPE were close to that of a cellulose separator system (ESW∼3.2-3.6 V) at 20 °C, and were relatively higher than a cellulose system at 100 °C: 2.1-2.5 V and 1.8 V respectively. Furthermore, floating experiments at 100 °C (holding voltage at 2 V) revealed the exceptionally high stability of SGPE, with a residual capacitance of 93% after 500 h. This high electrochemical performance demonstrated the potential of semi-IPN SGPE as separator/electrolyte for high performance supercapacitors.

Multicomponent membranes

DOEpatents

Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

1988-01-01

A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

Radioisotope Detection Device and Methods of Radioisotope Collection

DOEpatents

Tranter, Troy J [Idaho Falls, ID; Oertel, Christopher P [Idaho Falls, ID; Giles, John R [Pocatello, ID; Mann, Nicholas R [Rigby, ID; McIlwain, Michael E [Idaho Falls, ID

2011-04-12

A device for collection of radionuclides includes a mixture of a polymer, a fluorescent organic scintillator and a chemical extractant. A radionuclide detector system includes a collection device comprising a mixture of a polymer, a fluorescent agent and a selective ligand. The system includes at least one photomultiplier tube (PMT). A method of detecting radionuclides includes providing a collector device comprising a mixture comprising a polymer, a fluorescent organic scintillator and a chemical extractant. An aqueous environment is exposed to the device and radionuclides are collected from the environment. Radionuclides can be concentrated within the device.

Wetting phenomenon in the liquid-vapor phase coexistence of a partially miscible Lennard-Jones binary mixture

NASA Astrophysics Data System (ADS)

Ramírez-Santiago, Guillermo; Díaz-Herrera, Enrique; Moreno Razo, José A.

2004-03-01

We have carried out extensive equilibrium MD simulations to study wetting phenomena in the liquid-vapor phase coexistence of a partially miscible binary LJ mixture. We find that in the temperature range 0.60 ≤ T^* < 0.80, the system separates forming a liquid A-liquid B interface in coexistence with the vapor phase. At higher temperatures, 0.80 ≤ T^* < 1.25 the liquid phases are wet by the vapor phase. By studying the behavior of the surface tension as a function of temperature we estimate the wetting transition temperature (WTT) to be T^*_w≃ 0.80. The adsorption of molecules at the liquid-liquid interface shows a discontinuity at about T^*≃ 0.79 suggesting that the wetting transition is a first order phase transition. These results are in agreement with some experiments carried out in fluid binary mixtures. In addition, we estimated the consolute temperature to be T^* _cons≃ 1.25. The calculated phase diagram of the mixture suggest the existence of a tricritical point.

Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

PubMed Central

Bates, Richard; Battistin, Michele; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Riva, Enrico Da; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

2014-01-01

We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions. PMID:24961217

Novel spectrophotometric methods for simultaneous determination of timolol and dorzolamide in their binary mixture.

PubMed

Lotfy, Hayam Mahmoud; Hegazy, Maha A; Rezk, Mamdouh R; Omran, Yasmin Rostom

2014-05-21

Two smart and novel spectrophotometric methods namely; absorbance subtraction (AS) and amplitude modulation (AM) were developed and validated for the determination of a binary mixture of timolol maleate (TIM) and dorzolamide hydrochloride (DOR) in presence of benzalkonium chloride without prior separation, using unified regression equation. Additionally, simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of the binary mixture namely; simultaneous ratio subtraction (SRS), ratio difference (RD), ratio subtraction (RS) coupled with extended ratio subtraction (EXRS), constant multiplication method (CM) and mean centering of ratio spectra (MCR). The proposed spectrophotometric procedures do not require any separation steps. Accuracy, precision and linearity ranges of the proposed methods were determined and the specificity was assessed by analyzing synthetic mixtures of both drugs. They were applied to their pharmaceutical formulation and the results obtained were statistically compared to that of a reported spectrophotometric method. The statistical comparison showed that there is no significant difference between the proposed methods and the reported one regarding both accuracy and precision. Copyright © 2014 Elsevier B.V. All rights reserved.

Separating Iso-Propanol-Toluene mixture by azeotropic distillation

NASA Astrophysics Data System (ADS)

Iqbal, Asma; Ahmad, Syed Akhlaq

2018-05-01

The separation of Iso-Propanol-Toluene azeotropic mixture using Acetone as an entrainer has been simulated on Aspen Plus software package using rigorous methods. Calculations of the vapor-liquid equilibrium for the binary system are done using UNIQUAC-RK model which gives a good agreement with the experimental data reported in literature. The effects of the Reflux ratio (RR), distillate-to-feed molar ratio (D/F), feed stage, solvent feed stage, Total no. of stages and solvent feed temperature on the product purities and recoveries are studied to obtain their optimum values that give the maximum purity and recovery of products. The configuration consists of 20 theoretical stages with an equimolar feed of binary mixture. The desired separation of binary mixture has been achieved at the feed stage and an entrainer feeding stage of 15 and 12 respectively with the reflux ratios of 2.5 and 4.0, and D/F ratio of 0.75 and 0.54 respectively in the two columns. The simulation results thus obtained are useful to setup the optimal column configuration of the azeotropic distillation process.

Antiandrogenic activity of phthalate mixtures: Validity of concentration addition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christen, Verena; Crettaz, Pierre; Oberli-Schrämmli, Aurelia

2012-03-01

Phthalates and bisphenol A have very widespread use leading to significant exposure of humans. They are suspected to interfere with the endocrine system, including the androgen, estrogen and the thyroid hormone system. Here we analyzed the antiandrogenic activity of six binary, and one ternary mixture of phthalates exhibiting complete antiandrogenic dose–response curves, and binary mixtures of phthalates and bisphenol A at equi-effective concentrations of EC{sub 10}, EC{sub 25} and EC{sub 50} in MDA-kb2 cells. Mixture activity followed the concentration addition (CA) model with a tendency to synergism at high and antagonism at low concentrations. Isoboles and the toxic unit approachmore » (TUA) confirmed the additive to synergistic activity of the binary mixtures BBP + DBP, DBP + DEP and DEP + BPA at high concentrations. Both methods indicate a tendency to antagonism for the EC{sub 10} mixtures BBP + DBP, BBP + DEP and DBP + DEP, and the EC{sub 25} mixture of DBP + BPA. A ternary mixture revealed synergism at the EC{sub 50}, and weak antagonistic activity at the EC{sub 25} level by the TUA. A mixture of five phthalates representing a human urine composition and reflecting exposure to corresponding parent compounds showed no antiandrogenic activity. Our study demonstrates that CA is an appropriate concept to account for mixture effects of antiandrogenic phthalates and bisphenol A. The interaction indicates a departure from additivity to antagonism at low concentrations, probably due to interaction with the androgen receptor and/or cofactors. This study emphasizes that a risk assessment of phthalates should account for mixture effects by applying the CA concept. -- Highlights: ► Antiandrogenic activity of mixtures of 2 and 3 phthalates are assessed in MDA-kb2 cells. ► Mixture activities followed the concentration addition model. ► A tendency to synergism at high and antagonism at low levels occurred.« less

Current applications of foams formed from mixed surfactant-polymer solutions.

PubMed

Bureiko, Andrei; Trybala, Anna; Kovalchuk, Nina; Starov, Victor

2015-08-01

Foams cannot be generated without the use of special foaming agents, as pure liquids do not foam. The most common foaming agents are surfactants, however often for foam stability one active agent is not enough, it is necessary to add other component to increase foam lifetime. Foams on everyday use are mostly made from mixture of different components. Properly chosen combinations of two active ingredients lead to a faster foam formation and increased foam stability. During the last decade polymers (mainly polyelectrolytes and proteins) have become frequently used additives to foaming solutions. Mixtures of surfactants and polymers often demonstrate different foaming properties in comparison to surfactant only or polymer only solutions. The nature of surfactant-polymer interactions is complicated and prediction of resulting foaming properties of such formulations is not straightforward. Properties and foaming of surfactant-polymer mixtures are discussed as well as current applications of foams and foaming agents as foams are widely used in cosmetics, pharmaceutics, medicine and the food industry. Copyright © 2014 Elsevier B.V. All rights reserved.

Lateral Diffusion in a DMPC:DMPE-EO Binary Monolayer at the Air/Water Interface

NASA Astrophysics Data System (ADS)

Adalsteinsson, Thorsteinn; Porter, Ryan; Yu, Hyuk

2002-03-01

Polyethylene glycol tethered phospholipids (lipo-polymers) have recently attracted attention for improving the stability of liposomes and other bilayer delivery systems. Here, we report a study of surface pressure measurement and diffusion measurements of a probe lipid (NBD-DMPC) in a binary monolayer of DMPC and DMPE-EO at the Air/Water interface. Our findings are that the DMPE-EO lipo-polymer desorbs from the interface at intermediate surface pressures if the EO tail is sufficiently large (i.e. EO_45) and does not interfere with the diffusion of the probe thereafter. In the case where the EO tail is short (i.e. EO_17) the lipo-polymer retards the diffusion of the probe, but as the surface pressure increases, the diffusion behavior approaches that of pure DMPC monolayer independent of lipo-polymer. Thus, we conclude that the surface pressure and EO molar mass dependent desorption of the lipo-polymer modulates the probe diffusion retardation.

The virial coefficients of hard hypersphere binary mixtures

NASA Astrophysics Data System (ADS)

Enciso, E.; Almarza, N. G.; Gonzalez, M. A.; Bermejo, F. J.

The third, fourth and fifth virial coefficients of hard hypersphere binary mixtures with dimensionality d = 4, 5 have been calculated for size ratios R ≥0.1, R ı σ22 / σ11 , where σ ii is the diameter of component i . The composition independent partial virial coefficients have been evaluated by Monte Carlo integration of the corresponding Mayer modified star diagrams. The results are compared with the predictions of Santos, S., Yuste, S. B., and Lopez de Haro, M., 1999, Molec. Phys ., 96 , 1 of the equation of state of a multicomponent mixture of hard hyperspheres, and the good agreement gives strong support to the validity of that recipe.

Ion-water wires in imidazolium-based ionic liquid/water solutions induce unique trends in density.

PubMed

Ghoshdastidar, Debostuti; Senapati, Sanjib

2016-03-28

Ionic liquid/water binary mixtures are rapidly gaining popularity as solvents for dissolution of cellulose, nucleobases, and other poorly water-soluble biomolecules. Hence, several studies have focused on measuring the thermophysical properties of these versatile mixtures. Among these, 1-ethyl-3-methylimidazolium ([emim]) cation-based ILs containing different anions exhibit unique density behaviours upon addition of water. While [emim][acetate]/water binary mixtures display an unusual rise in density with the addition of low-to-moderate amounts of water, those containing the [trifluoroacetate] ([Tfa]) anion display a sluggish decrease in density. The density of [emim][tetrafluoroborate] ([emim][BF4])/water mixtures, on the other hand, declines rapidly in close accordance with the experimental reports. Here, we unravel the structural basis underlying this unique density behavior of [emim]-based IL/water mixtures using all-atom molecular dynamics (MD) simulations. The results revealed that the distinct nature of anion-water hydrogen bonded networks in the three systems was a key in modulating the observed unique density behaviour. Vast expanses of uninterrupted anion-water-anion H-bonded stretches, denoted here as anion-water wires, induced significant structuring in [emim][Ac]/water mixtures that resulted in the density rise. Conversely, the presence of intermittent large water clusters disintegrated the anion-water wires in [emim][Tfa]/water and [emim][BF4]/water mixtures to cause a monotonic density decrease. The differential nanostructuring affected the dynamics of the solutions proportionately, with the H-bond making and breaking dynamics found to be greatly retarded in [emim][Ac]/water mixtures, while it exhibited a faster relaxation in the other two binary solutions.

Improving the de-agglomeration and dissolution of a poorly water soluble drug by decreasing the agglomerate strength of the cohesive powder.

PubMed

Allahham, Ayman; Stewart, Peter J; Das, Shyamal C

2013-11-30

Influence of ternary, poorly water-soluble components on the agglomerate strength of cohesive indomethacin mixtures during dissolution was studied to explore the relationship between agglomerate strength and extent of de-agglomeration and dissolution of indomethacin (Ind). Dissolution profiles of Ind from 20% Ind-lactose binary mixtures, and ternary mixtures containing additional dibasic calcium phosphate (1% or 10%; DCP), calcium sulphate (10%) and talc (10%) were determined. Agglomerate strength distributions were estimated by Monte Carlo simulation of particle size, work of cohesion and packing fraction distributions. The agglomerate strength of Ind decreased from 1.19 MPa for the binary Ind mixture to 0.84 MPa for 1DCP:20Ind mixture and to 0.42 MPa for 1DCP:2Ind mixture. Both extent of de-agglomeration, demonstrated by the concentration of the dispersed indomethacin distribution, and extent of dispersion, demonstrated by the particle size of the dispersed indomethacin, were in descending order of 1DCP:2Ind>1DCP:20Ind>binary Ind. The addition of calcium sulphate dihydrate and talc also reduced the agglomerate strength and improved de-agglomeration and dispersion of indomethacin. While not definitively causal, the improved de-agglomeration and dispersion of a poorly water soluble drug by poorly water soluble components was related to the agglomerate strength of the cohesive matrix during dissolution. Copyright © 2013 Elsevier B.V. All rights reserved.

Method for producing hydrocarbon and alcohol mixtures. [Patent application

DOEpatents

Compere, A.L.; Googin, J.M.; Griffith, W.L.

1980-12-01

It is an object of this invention to provide an efficient process for extracting alcohols and ketones from an aqueous solution containing the same into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. Another object of the invention is to provide a mixture consisting of hydrocarbon, alcohols or ketones, polyoxyalkylene polymer and water which can be directly added to fuels or further purified. The above stated objects are achieved in accordance with a preferred embodiment of the invention by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5 to 18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is mixed in the presence or one or more of a group of polyoxyalkylene polymers described in detail hereinafter; the fermentation alcohol being extracted into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures

PubMed Central

Conrad, Jacinta C.

2014-01-01

The behavior of confined colloidal suspensions with attractive interparticle interactions is critical to the rational design of materials for directed assembly1-3, drug delivery4, improved hydrocarbon recovery5-7, and flowable electrodes for energy storage8. Suspensions containing fluorescent colloids and non-adsorbing polymers are appealing model systems, as the ratio of the polymer radius of gyration to the particle radius and concentration of polymer control the range and strength of the interparticle attraction, respectively. By tuning the polymer properties and the volume fraction of the colloids, colloid fluids, fluids of clusters, gels, crystals, and glasses can be obtained9. Confocal microscopy, a variant of fluorescence microscopy, allows an optically transparent and fluorescent sample to be imaged with high spatial and temporal resolution in three dimensions. In this technique, a small pinhole or slit blocks the emitted fluorescent light from regions of the sample that are outside the focal volume of the microscope optical system. As a result, only a thin section of the sample in the focal plane is imaged. This technique is particularly well suited to probe the structure and dynamics in dense colloidal suspensions at the single-particle scale: the particles are large enough to be resolved using visible light and diffuse slowly enough to be captured at typical scan speeds of commercial confocal systems10. Improvements in scan speeds and analysis algorithms have also enabled quantitative confocal imaging of flowing suspensions11-16,37. In this paper, we demonstrate confocal microscopy experiments to probe the confined phase behavior and flow properties of colloid-polymer mixtures. We first prepare colloid-polymer mixtures that are density- and refractive-index matched. Next, we report a standard protocol for imaging quiescent dense colloid-polymer mixtures under varying confinement in thin wedge-shaped cells. Finally, we demonstrate a protocol for imaging colloid-polymer mixtures during microchannel flow. PMID:24894062

Hierarchically self-assembled hexagonal honeycomb and kagome superlattices of binary 1D colloids.

PubMed

Lim, Sung-Hwan; Lee, Taehoon; Oh, Younghoon; Narayanan, Theyencheri; Sung, Bong June; Choi, Sung-Min

2017-08-25

Synthesis of binary nanoparticle superlattices has attracted attention for a broad spectrum of potential applications. However, this has remained challenging for one-dimensional nanoparticle systems. In this study, we investigate the packing behavior of one-dimensional nanoparticles of different diameters into a hexagonally packed cylindrical micellar system and demonstrate that binary one-dimensional nanoparticle superlattices of two different symmetries can be obtained by tuning particle diameter and mixing ratios. The hexagonal arrays of one-dimensional nanoparticles are embedded in the honeycomb lattices (for AB 2 type) or kagome lattices (for AB 3 type) of micellar cylinders. The maximization of free volume entropy is considered as the main driving force for the formation of superlattices, which is well supported by our theoretical free energy calculations. Our approach provides a route for fabricating binary one-dimensional nanoparticle superlattices and may be applicable for inorganic one-dimensional nanoparticle systems.Binary mixtures of 1D particles are rarely observed to cooperatively self-assemble into binary superlattices, as the particle types separate into phases. Here, the authors design a system that avoids phase separation, obtaining binary superlattices with different symmetries by simply tuning the particle diameter and mixture composition.

Additive and synergistic antiandrogenic activities of mixtures of azol fungicides and vinclozolin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christen, Verena; Crettaz, Pierre; Fent, Karl, E-mail: karl.fent@fhnw.ch

Objective: Many pesticides including pyrethroids and azole fungicides are suspected to have an endocrine disrupting property. At present, the joint activity of compound mixtures is only marginally known. Here we tested the hypothesis that the antiandrogenic activity of mixtures of azole fungicides can be predicted by the concentration addition (CA) model. Methods: The antiandrogenic activity was assessed in MDA-kb2 cells. Following assessing single compounds activities mixtures of azole fungicides and vinclozolin were investigated. Interactions were analyzed by direct comparison between experimental and estimated dose–response curves assuming CA, followed by an analysis by the isobole method and the toxic unit approach.more » Results: The antiandrogenic activity of pyrethroids deltamethrin, cypermethrin, fenvalerate and permethrin was weak, while the azole fungicides tebuconazole, propiconazole, epoxiconazole, econazole and vinclozolin exhibited strong antiandrogenic activity. Ten binary and one ternary mixture combinations of five antiandrogenic fungicides were assessed at equi-effective concentrations of EC{sub 25} and EC{sub 50}. Isoboles indicated that about 50% of the binary mixtures were additive and 50% synergistic. Synergism was even more frequently indicated by the toxic unit approach. Conclusion: Our data lead to the conclusion that interactions in mixtures follow the CA model. However, a surprisingly high percentage of synergistic interactions occurred. Therefore, the mixture activity of antiandrogenic azole fungicides is at least additive. Practice: Mixtures should also be considered for additive antiandrogenic activity in hazard and risk assessment. Implications: Our evaluation provides an appropriate “proof of concept”, but whether it equally translates to in vivo effects should further be investigated. - Highlights: • Humans are exposed to pesticide mixtures such as pyrethroids and azole fungicides. • We assessed the antiandrogenicity of pyrethroids and azole fungizides. • Many azole fungicides showed significant antiandrogenic activity . • Many binary mixtures of antiandrogenic azole fungicides showed synergistic interactions. • Concentration addition of pesticides in mixtures should be considered.« less

Strong cooperative effect of oppositely charged surfactant mixtures on their adsorption and packing at the air-water interface and interfacial water structure.

PubMed

Nguyen, Khoi T; Nguyen, Tuan D; Nguyen, Anh V

2014-06-24

Remarkable adsorption enhancement and packing of dilute mixtures of water-soluble oppositely-charged surfactants, sodium dodecyl sulfate (SDS) and dodecyl amine hydrochloride (DAH), at the air-water interface were observed by using sum frequency generation spectroscopy and tensiometry. The interfacial water structure was also observed to be significantly influenced by the SDS-DAH mixtures, differently from the synergy of the single surfactants. Most strikingly, the obtained spectroscopic evidence suggests that the interfacial hydrophobic alkyl chains of the binary mixtures assemble differently from those of single surfactants. This study highlights the significance of the cooperative interaction between the headgroups of oppositely charged binary surfactant systems and subsequently provides some insightful observations about the molecular structure of the air-aqueous interfacial water molecules and, more importantly, about the packing nature of the surfactant hydrophobic chains of dilute SDS-DAH mixtures of concentration below 1% of the CMC.

Dielectric relaxation and hydrogen bonding interaction in xylitol-water mixtures using time domain reflectometry

NASA Astrophysics Data System (ADS)

Rander, D. N.; Joshi, Y. S.; Kanse, K. S.; Kumbharkhane, A. C.

2016-01-01

The measurements of complex dielectric permittivity of xylitol-water mixtures have been carried out in the frequency range of 10 MHz-30 GHz using a time domain reflectometry technique. Measurements have been done at six temperatures from 0 to 25 °C and at different weight fractions of xylitol (0 < W X ≤ 0.7) in water. There are different models to explain the dielectric relaxation behaviour of binary mixtures, such as Debye, Cole-Cole or Cole-Davidson model. We have observed that the dielectric relaxation behaviour of binary mixtures of xylitol-water can be well described by Cole-Davidson model having an asymmetric distribution of relaxation times. The dielectric parameters such as static dielectric constant and relaxation time for the mixtures have been evaluated. The molecular interaction between xylitol and water molecules is discussed using the Kirkwood correlation factor ( g eff ) and thermodynamic parameter.

Molecular interactions and structures in ethylene glycol-ethanol and ethylene glycol-water solutions at 303 K on densities, viscosities, and refractive indices data

NASA Astrophysics Data System (ADS)

Deosarkar, S. D.; Ghatbandhe, A. S.

2014-01-01

Molecular interactions and structural fittings in binary ethylene glycol + ethanol (EGE, x EG = 0.4111-0.0418) and ethylene glycol + water (EGW, x EG = 0.1771-0.0133) mixtures were studied through the measurement of densities (ρ), viscosities (η), and refractive indices ( n D ) at 303.15 K. Excess viscosities (η E ), molar volumes ( V m ), excess molar volumes ( V {/m E }), and molar retractions ( R M ) of the both binary systems were computed from measured properties. The measured and computed properties have been used to understand the molecular interactions in unlike solvents and structural fittings in these binary mixtures.

Dielectric properties of benzylamine in 1,2,6-hexanetriol mixture using time domain reflectometry technique

NASA Astrophysics Data System (ADS)

Swami, M. B.; Hudge, P. G.; Pawar, V. P.

The dielectric properties of binary mixtures of benzylamine-1,2,6-hexantriol mixtures at different volume fractions of 1,2,6-hexanetriol have been measured using Time Domain Reflectometry (TDR) technique in the frequency range of 10 MHz to 30 GHz. Complex permittivity spectra were fitted using Havriliak-Negami equation. By using least square fit method the dielectric parameters such as static dielectric constant (ɛ0), dielectric constant at high frequency (ɛ∞), relaxation time τ (ps) and relaxation distribution parameter (β) were extracted from complex permittivity spectra at 25∘C. The intramolecular interaction of different molecules has been discussed using the Kirkwood correlation factor, Bruggeman factor. The Kirkwood correlation factor (gf) and effective Kirkwood correlation factor (geff) indicate the dipole ordering of the binary mixtures.

Flash evaporation of liquid monomer particle mixture

DOEpatents

Affinito, John D.; Darab, John G.; Gross, Mark E.

1999-01-01

The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer.

Metastable liquid lamellar structures in binary and ternary mixtures of Lennard-Jones fluids

NASA Astrophysics Data System (ADS)

Díaz-Herrera, Enrique; Ramírez-Santiago, Guillermo; Moreno Razo, José A.

2004-03-01

We have carried out extensive equilibrium MD simulations to investigate the Liquid-Vapor coexistence in partially miscible binary and ternary mixtures LJ fluids. We have studied in detail the time evolution of the density profiles and the interfacial properties in a temperature region of the phase diagram where the condensed phase is demixed. The composition of the mixtures are fixed, 50% for the binary mixture and 33.33% for the ternary mixture. The results of the simulations clearly indicate that in the range of temperatures 78 < T < 102 ^oK,--in the scale of argon-- the system evolves towards a metastable alternated liquid-liquid lamellar state in coexistence with its vapor phase. These states can be achieved if the initial configuration is fully disordered, that is, when the particles of the fluids are randomly placed on the sites of an FCC crystal or the system is completely mixed. As temperature decreases these states become very well defined and more stable in time. We find that below 90 ^oK, the alternated liquid-liquid lamellar state remains alive for 80 ns, in the scale of argon, the longest simulation we have carried out. Nonetheless, we believe that in this temperature region these states will be alive for even much longer times.

Viscous slip coefficients for binary gas mixtures measured from mass flow rates through a single microtube

NASA Astrophysics Data System (ADS)

Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.

2016-09-01

The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip boundary condition can be applied. The measured viscous slip coefficients of binary gas mixtures exhibit a concave function of the molar ratio of the mixture, showing a similar profile with numerical results. However, from the detailed comparison between the measured and numerical values with the complete and incomplete accommodation at a surface, it is inappropriate to estimate the viscous slip coefficient for the mixture numerically by employing separately measured tangential momentum accommodation coefficient for each component. The time variation of the molar ratio in the downstream chamber was measured by sampling the gas from the chamber using the quadrupole mass spectrometer. In our measurements, it is indicated that the volume flow rate of argon is larger than that of helium because of the difference in the tangential momentum accommodation coefficient.

Birthdays and the Binary System: A Magical Mixture.

ERIC Educational Resources Information Center

Karp, Karen S.; Ronau, Robert N.

1997-01-01

Presents an activity involving the use of students' birth dates. Activity includes a classic binary representation of numerical values. In the Green Machine, Sorting Cards, and Window Cards, students observe, describe, and analyze patterns. (PVD)

QSAR prediction of additive and non-additive mixture toxicities of antibiotics and pesticide.

PubMed

Qin, Li-Tang; Chen, Yu-Han; Zhang, Xin; Mo, Ling-Yun; Zeng, Hong-Hu; Liang, Yan-Peng

2018-05-01

Antibiotics and pesticides may exist as a mixture in real environment. The combined effect of mixture can either be additive or non-additive (synergism and antagonism). However, no effective predictive approach exists on predicting the synergistic and antagonistic toxicities of mixtures. In this study, we developed a quantitative structure-activity relationship (QSAR) model for the toxicities (half effect concentration, EC 50 ) of 45 binary and multi-component mixtures composed of two antibiotics and four pesticides. The acute toxicities of single compound and mixtures toward Aliivibrio fischeri were tested. A genetic algorithm was used to obtain the optimized model with three theoretical descriptors. Various internal and external validation techniques indicated that the coefficient of determination of 0.9366 and root mean square error of 0.1345 for the QSAR model predicted that 45 mixture toxicities presented additive, synergistic, and antagonistic effects. Compared with the traditional concentration additive and independent action models, the QSAR model exhibited an advantage in predicting mixture toxicity. Thus, the presented approach may be able to fill the gaps in predicting non-additive toxicities of binary and multi-component mixtures. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ion solvation in polymer blends and block copolymer melts: effects of chain length and connectivity on the reorganization of dipoles.

PubMed

Nakamura, Issei

2014-05-29

We studied the thermodynamic properties of ion solvation in polymer blends and block copolymer melts and developed a dipolar self-consistent field theory for polymer mixtures. Our theory accounts for the chain connectivity of polymerized monomers, the compressibility of the liquid mixtures under electrostriction, the permanent and induced dipole moments of monomers, and the resultant dielectric contrast among species. In our coarse-grained model, dipoles are attached to the monomers and allowed to rotate freely in response to electrostatic fields. We demonstrate that a strong electrostatic field near an ion reorganizes dipolar monomers, resulting in nonmonotonic changes in the volume fraction profile and the dielectric function of the polymers with respect to those of simple liquid mixtures. For the parameter sets used, the spatial variations near an ion can be in the range of 1 nm or larger, producing significant differences in the solvation energy among simple liquid mixtures, polymer blends, and block copolymers. The solvation energy of an ion depends substantially on the chain length in block copolymers; thus, our theory predicts the preferential solvation of ions arising from differences in chain length.

Pycnonuclear reaction rates for binary ionic mixtures

NASA Technical Reports Server (NTRS)

Ichimaru, S.; Ogata, S.; Van Horn, H. M.

1992-01-01

Through a combination of compositional scaling arguments and examinations of Monte Carlo simulation results for the interparticle separations in binary-ionic mixture (BIM) solids, we have derived parameterized expressions for the BIM pycnonuclear rates as generalizations of those in one-component solids obtained previously by Salpeter and Van Horn and by Ogata et al. We have thereby discovered a catalyzing effect of the heavier elements, which enhances the rates of reactions among the lighter elements when the charge ratio exceeds a critical value of approximately 2.3.

Solubility of pioglitazone hydrochloride in binary mixtures of polyethylene glycol 400 with ethanol, propylene glycol, N-methyl-2-pyrrolidone, and water at 25 degrees C.

PubMed

Jouyban, Abolghasem; Soltanpour, Shahla

2010-09-01

The solubility of pioglitazone hydrochloride in binary mixtures of polyethylene glycol 400 with ethanol, N-methyl-2-pyrrolidone, propylene glycol, and water at 25 degrees C are reported. The generated data are fitted to the Jouyban-Acree model and the mean relative deviations are 2.6%, 1.5%, 5.8%, and 7.4%, respectively for ethanol, N-methyl-2-pyrrolidone, propylene glycol, and water.

Instability of a solidifying binary mixture

NASA Technical Reports Server (NTRS)

Antar, B. N.

1982-01-01

An analysis is performed on the stability of a solidifying binary mixture due to surface tension variation of the free liquid surface. The basic state solution is obtained numerically as a nonstationary function of time. Due to the time dependence of the basic state, the stability analysis is of the global type which utilizes a variational technique. Also due to the fact that the basic state is a complex function of both space and time, the stability analysis is performed through numerical means.

Soret motion in non-ionic binary molecular mixtures

NASA Astrophysics Data System (ADS)

Leroyer, Yves; Würger, Alois

2011-08-01

We study the Soret coefficient of binary molecular mixtures with dispersion forces. Relying on standard transport theory for liquids, we derive explicit expressions for the thermophoretic mobility and the Soret coefficient. Their sign depends on composition, the size ratio of the two species, and the ratio of Hamaker constants. Our results account for several features observed in experiment, such as a linear variation with the composition; they confirm the general rule that small molecules migrate to the warm, and large ones to the cold.

A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

EPA Science Inventory

Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

Grafting of vinyl acetate-ethylacrylate binary monomer mixture onto guar gum.

PubMed

Singh, Vandana; Singh, Angela; Joshi, Sneha; Malviya, Tulika

2016-03-01

Present article reports on guar gum (GG) functionalization through graftcopolymerization of vinylacetate (VAC) and ethylacrylate (EA) from their binary mixtures. The potassium persulfate/ascorbic acid (KPS/AA) redox initiator system has been used for the binary grafting under the previously optimized conditions for VAC grafting at guar gum. The concentration of ascorbic acid (AA), persulfate (KPS), and grafting temperature were varied to optimize the binary grafting. A preliminary investigation revealed that the copolymer has excellent ability to capture Hg(II) from aqueous solution. It was observed that the optimum % grafting sample (CP3) was best at Hg(II) adsorption. CP3 and mercury loaded CP3 (CP3-Hg) have been extensively characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Thermo gravimetric analysis (TGA) and a plausible mechanism for the grafting has been proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

Distribution of short block copolymer chains in Binary Blends of Block Copolymers Having Hydrogen Bonding

NASA Astrophysics Data System (ADS)

Kwak, Jongheon; Han, Sunghyun; Kim, Jin Kon

2014-03-01

A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to obtain various microdomains that could not be expected for neat block copolymer. For instance, the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyrene-block-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To know the exact location of short block copolymer chains at the interface, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (dPS-b-PHS) and prepared a binary mixture with PS-b-P2VP. We investigate, via small angle X-ray scattering (SAXS) and neutron reflectivity (NR), the exact location of shorter dPS block chain near the interface of the microdomains.

Flash evaporation of liquid monomer particle mixture

DOEpatents

Affinito, J.D.; Darab, J.G.; Gross, M.E.

1999-05-11

The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer. 3 figs.

Dielectric and conformational studies of hydrogen bonded 2-ethoxyethanol and ethyl methyl ketone system

NASA Astrophysics Data System (ADS)

Pattebahadur, Kanchan. L.; Deshmukh, S. D.; Mohod, A. G.; Undre, P. B.; Patil, S. S.; Khirade, P. W.

2018-05-01

The Dielectric constant, density and refractive index of binary mixture of 2-ethoxy ethanol (2-EE) with ethyl methyl ketone (EMK) including those of the pure liquids were measured for 11 concentrations at 25°C temperature. The experimental data is used to calculate the Excess molar volume, Excess dielectric constant, Kirkwood correlation factor and Bruggemann factor. The excess parameters results were fitted to the Redlich-Kister type polynomial equation to derive its fitting coefficient. The Kirkwood correlation factor of the mixture has been discussed to yield information about solute solvent interaction. The Bruggeman plot shows a deviation from linearity. The FT-IR spectra of pure and their binary mixtures are also studied.

Domain wall suppression in trapped mixtures of Bose-Einstein condensates

NASA Astrophysics Data System (ADS)

Pepe, Francesco V.; Facchi, Paolo; Florio, Giuseppe; Pascazio, Saverio

2012-08-01

The ground-state energy of a binary mixture of Bose-Einstein condensates can be estimated for large atomic samples by making use of suitably regularized Thomas-Fermi density profiles. By exploiting a variational method on the trial densities the energy can be computed by explicitly taking into account the normalization condition. This yields analytical results and provides the basis for further improvement of the approximation. As a case study, we consider a binary mixture of 87Rb atoms in two different hyperfine states in a double-well potential and discuss the energy crossing between density profiles with different numbers of domain walls, as the number of particles and the interspecies interaction vary.

Thermophysical properties of N, N-dimethylacetamide mixtures with n-butanol

NASA Astrophysics Data System (ADS)

Maharolkar, Aruna P.; Murugkar, A. G.; Khirade, P. W.; Mehrotra, S. C.

2017-09-01

The refraction, dielectric, viscosity, density, data of the binary mixtures of N, N-dimethylacetamide (DMA) with n-butanol at 308.15 and 313.15 K. The measured parameters used to obtain derived properties like Bruggeman factor, molar refraction and excess static dielectric constant, excess inverse relaxation time, excess molar volume and excess viscosity, excess molar refraction. The variation in magnitude with composition and temperature of these quantities has been used to discuss the type, strength and nature of binary interactions. Results confirm that there are strong hydrogen-bond interactions between unlike molecules of DMA+ n-butanol mixtures and that 1: 1 complexes are formed and strength of intermolecular interaction increases with temperature.

Fragility and glass transition for binary mixtures of 1,2-propanediol and LiBF4

NASA Astrophysics Data System (ADS)

Terashima, Y.; Mori, M.; Sugimoto, N.; Takeda, K.

2014-04-01

The fragility and glass transition for binary mixtures of 1,2-propanediol and LiBF4 were investigated by measuring the heating rate dependence of glass transition temperature (Tg) using differential scanning calorimetry. With increasing LiBF4 mole fraction, x, up to 0.25, fragility, m, increased rapidly from 53 to 85, and then remained approximately unchanged for x > 0.25. The concentration dependences of Tg and heat capacity jump at Tg also showed anomalies around x = 0.25. We suggest this mixture transformed from a moderate to quite fragile liquid at x = 0.25 because of a structural change from a hydrogen-bonding- to ionic-interaction-dominant system.

The Soret Effect in Liquid Mixtures - A Review

NASA Astrophysics Data System (ADS)

Köhler, Werner; Morozov, Konstantin I.

2016-07-01

The Soret effect describes diffusive motion that originates from a temperature gradient. It is observed in mixtures of gases, liquids and even solids. Although there is a formal phenomenological description based on linear nonequilibrium thermodynamics, the Soret effect is a multicause phenomenon and there is no univocal microscopic picture. After a brief historical overview and an outline of the fundamental thermodynamic concepts, this review focuses on thermodiffusion in binary and ternary liquid mixtures. The most important experimental techniques used nowadays are introduced. Then, a modern development in studying thermal diffusion, the discovery of both integral and specific additivity laws, is discussed. The former relate to the general behavior of the substances in a temperature field according to their thermophobicities, which prove to be pure component properties. The thermophobicities allow for a convenient classification of the phenomenon, a simple interpretation and a proper estimation and prediction of the thermodiffusion parameters. The specific laws relate to the additivity of the particular contributions. Among the latter, we discuss the isotopic Soret effect and the so-called chemical contribution. From the theoretical side, there are kinetic and thermodynamic theories, and the nature of the driving forces of thermodiffusion can be either of volume or surface type. Besides analytical models, computer simulations become increasingly important. Polymer solutions are special as they represent highly asymmetric molecular systems with a molar mass-independent thermophoretic mobility. Its origin is still under debate, and draining and non-draining models are presently discussed. Finally, some discussion is devoted to ternary mixtures, which only recently have been investigated in more detail.

Dynamics of dense granular flows of small-and-large-grain mixtures in an ambient fluid.

PubMed

Meruane, C; Tamburrino, A; Roche, O

2012-08-01

Dense grain flows in nature consist of a mixture of solid constituents that are immersed in an ambient fluid. In order to obtain a good representation of these flows, the interaction mechanisms between the different constituents of the mixture should be considered. In this article, we study the dynamics of a dense granular flow composed of a binary mixture of small and large grains immersed in an ambient fluid. In this context, we extend the two-phase approach proposed by Meruane et al. [J. Fluid Mech. 648, 381 (2010)] to the case of flowing dense binary mixtures of solid particles, by including in the momentum equations a constitutive relation that describes the interaction mechanisms between the solid constituents in a dense regime. These coupled equations are solved numerically and validated by comparing the numerical results with experimental measurements of the front speed of gravitational granular flows resulting from the collapse, in ambient air or water, of two-dimensional granular columns that consisted of mixtures of small and large spherical particles of equal mass density. Our results suggest that the model equations include the essential features that describe the dynamics of grains flows of binary mixtures in an ambient fluid. In particular, it is shown that segregation of small and large grains can increase the front speed because of the volumetric expansion of the flow. This increase in flow speed is damped by the interaction forces with the ambient fluid, and this behavior is more pronounced in water than in air.

The effects of binary UV filter mixtures on the midge Chironomus riparius.

PubMed

Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

2016-06-15

Organic ultraviolet (UV) filters are used in a wide variety of products, including cosmetics, to prevent damage from UV light in tissues and industrial materials. Their extensive use has raised concerns about potential adverse effects in human health and aquatic ecosystems that accumulate these pollutants. To increase sun radiation protection, UV filters are commonly used in mixtures. Here, we studied the toxicity of binary mixtures of 4-methylbenzylidene camphor (4MBC), octyl-methoxycinnamate (OMC), and benzophenone-3 (BP-3), by evaluating the larval mortality of Chironomus riparius. Also molecular endpoints have been analyzed, including alterations in the expression levels of a gene related with the endocrine system (EcR, ecdysone receptor) and a gene related with the stress response (hsp70, heat shock protein 70). The results showed that the mortality caused by binary mixtures was similar to that observed for each compound alone; however, some differences in LC50 were observed between groups. Gene expression analysis showed that EcR mRNA levels increased in the presence of 0.1mg/L 4MBC but returned to normal levels after exposure to mixtures of 4MBC with 0.1, 1, and 10mg/L of BP-3 or OMC. In contrast, the hsp70 mRNA levels increased after exposure to the combinations tested of 4MBC and BP-3 or OMC mixtures. These data suggest that 4MBC, BP-3, and OMC may have antagonist effects on EcR gene transcription and a synergistic effect on hsp70 gene activation. This is the first experimental study to show the complex patterned effects of UV filter mixtures on invertebrates. The data suggest that the interactions within these chemicals mixtures are complex and show diverse effects on various endpoints. Copyright © 2016 Elsevier B.V. All rights reserved.

METALLURGICAL PROGRAMS: CALCULATION OF MASS FROM VOLUME, DENSITY OF MIXTURES, AND CONVERSION OF ATOMIC TO WEIGHT PERCENT

NASA Technical Reports Server (NTRS)

Degroh, H.

1994-01-01

The Metallurgical Programs include three simple programs which calculate solutions to problems common to metallurgical engineers and persons making metal castings. The first program calculates the mass of a binary ideal (alloy) given the weight fractions and densities of the pure components and the total volume. The second program calculates the densities of a binary ideal mixture. The third program converts the atomic percentages of a binary mixture to weight percentages. The programs use simple equations to assist the materials staff with routine calculations. The Metallurgical Programs are written in Microsoft QuickBASIC for interactive execution and have been implemented on an IBM PC-XT/AT operating MS-DOS 2.1 or higher with 256K bytes of memory. All instructions needed by the user appear as prompts as the software is used. Data is input using the keyboard only and output is via the monitor. The Metallurgical programs were written in 1987.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alhroob, M.; Boyd, G.; Hasib, A.

Precision ultrasonic measurements in binary gas systems provide continuous real-time monitoring of mixture composition and flow. Using custom micro-controller-based electronics, we have developed an ultrasonic instrument, with numerous potential applications, capable of making continuous high-precision sound velocity measurements. The instrument measures sound transit times along two opposite directions aligned parallel to - or obliquely crossing - the gas flow. The difference between the two measured times yields the gas flow rate while their average gives the sound velocity, which can be compared with a sound velocity vs. molar composition look-up table for the binary mixture at a given temperature andmore » pressure. The look-up table may be generated from prior measurements in known mixtures of the two components, from theoretical calculations, or from a combination of the two. We describe the instrument and its performance within numerous applications in the ATLAS experiment at the CERN Large Hadron Collider (LHC). The instrument can be of interest in other areas where continuous in-situ binary gas analysis and flowmetry are required. (authors)« less

Refractive index, molar refraction and comparative refractive index study of propylene carbonate binary liquid mixtures.

PubMed

Wankhede, Dnyaneshwar Shamrao

2012-06-01

Refractive indices (n) have been experimentally determined for the binary liquid-liquid mixtures of Propylene carbonate (PC) (1) with benzene, ethylbenzene, o-xylene and p-xylene (2) at 298.15, 303.15 and 308.15 K over the entire mole fraction range. The experimental values of n are utilised to calculate deviation in refractive index (Δn), molar refraction (R) and deviation in molar refraction (ΔR). A comparative study of Arago-Biot (A-B), Newton (NW), Eyring and John (E-J) equations for determining refractive index of a liquid has been carried out to test their validity for all the binary mixtures over the entire composition range at 298.15 K. Comparison of various mixing relations is represented in terms of average deviation (AVD). The Δn and ΔR values have been fitted to Redlich-Kister equation at 298.15 K and standard deviations have been calculated. The results are discussed in terms of intermolecular interactions present amongst the components.

Physical compatibility of binary and ternary mixtures of morphine and methadone with other drugs for parenteral administration in palliative care.

PubMed

Destro, Massimo; Ottolini, Luca; Vicentini, Lorenza; Boschetti, Silvia

2012-10-01

The parenteral administration of combinations of drugs is often necessary in palliative medicine, particularly in the terminal stage of life, when patients are no longer able to take medication orally. The use of infusers to administer continuous subcutaneous infusions is a well-established practice in the palliative care setting and enables several drugs to be given simultaneously, avoiding the need for repeated administrations and the effects of peaks and troughs in the doses of medication. The method is also appreciated by patients and caregivers in the home care setting because the devices and infusion sites are easy to manage. Despite their frequent use, however, the mixtures of drugs adopted in clinical practice are sometimes not supported by reliable data concerning their chemical and physical compatibility. The present study investigates the chemical compatibility of binary mixtures (morphine with ketorolac) and the physical compatibility of binary (morphine or methadone with ketorolac) or ternary mixtures (morphine with ketorolac and/or haloperidol, and/or dexamethasone, and/or metoclopramide, and/or hyoscine butylbromide) with a view to reducing the aleatory nature of the empirical use of such combinations, thereby increasing their safety and clinical appropriateness.

An odor interaction model of binary odorant mixtures by a partial differential equation method.

PubMed

Yan, Luchun; Liu, Jiemin; Wang, Guihua; Wu, Chuandong

2014-07-09

A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.

Lubrication model for evaporation of binary sessile drops

NASA Astrophysics Data System (ADS)

Williams, Adam; Sáenz, Pedro; Karapetsas, George; Matar, Omar; Sefiane, Khellil; Valluri, Prashant

2017-11-01

Evaporation of a binary mixture sessile drop from a solid substrate is a highly dynamic and complex process with flow driven both thermal and solutal Marangoni stresses. Experiments on ethanol/water drops have identified chaotic regimes on both the surface and interior of the droplet, while mixture composition has also been seen to govern drop wettability. Using a lubrication-type approach, we present a finite element model for the evaporation of an axisymmetric binary drop deposited on a heated substrate. We consider a thin drop with a moving contact line, taking also into account the commonly ignored effects of inertia which drives interfacial instability. We derive evolution equations for the film height, the temperature and the concentration field considering that the mixture comprises two ideally mixed volatile components with a surface tension linearly dependent on both temperature and concentration. The properties of the mixture such as viscosity also vary locally with concentration. We explore the parameter space to examine the resultant effects on wetting and evaporation where we find qualitative agreement with experiments in both these areas. This enables us to understand the nature of the instabilities that spontaneously emerge over the drop lifetime. EPSRC - EP/K00963X/1.

Laboratory Studies of Aedes aegypti Attraction to Ketones, Sulfides, and Primary Chloroalkanes Tested Alone and in Combination with L-Lactic Acid.

PubMed

Bernier, Ulrich R; Kline, Daniel L; Allan, Sandra A; Barnard, Donald R

2015-03-01

The attraction of female Aedes aegypti to single compounds and binary compositions containing L-lactic acid and an additional saturated compound from a set of ketones, sulfides, and chloroalkanes was studied using a triple-cage dual-port olfactometer. These chemical classes were studied because of their structural relation to acetone, dimethyl disulfide, and dichloromethane, which have all been reported to synergize attraction to L-lactic acid. Human odors, carbon dioxide, and the binary mixture of L-lactic acid and CO₂served as controls for comparison of attraction responses produced by the binary mixtures. All tested mixtures that contained chloroalkanes attracted mosquitoes at synergistic levels, as did L-lactic acid and CO₂. Synergism was less frequent in mixtures of L-lactic acid with sulfides and ketones; in the case of ketones, synergistic attraction was observed only for L-lactic acid combined with acetone or butanone. Suppression or inhibition of attraction response was observed for combinations that contained ketones of C7-C12 molecular chain length (optimum in the C8-C10 range). This inhibition effect is similar to that observed previously for specific ranges of carboxylic acids, aldehydes, and alcohols.

Mesoporous carbons and polymers

DOEpatents

Bell, William; Dietz, Steven

2004-05-18

A polymer is prepared by polymerizing a polymerizable component from a mixture containing the polymerizable component and a surfactant, the surfactant and the polymerizable component being present in the mixture in a molar ratio of at least 0.2:1, having an average pore size greater than 4 nm and a density greater than 0.1 g/cc. The polymerizable component can comprise a resorcinol/formaldehyde system and the mixture can comprise an aqueous solution or the polymerizable component can comprise a divinylbenzene/styrene system and the mixture can comprise an organic solution. Alternatively, the polymerizable component can comprise vinylidene chloride or a vinylidene chloride/divinylbenzene system. The polymer may be monolithic, have a BET surface area of at least about 50 m.sup.2 /g., include a quantity of at least one metal powder, or have an electrical conductivity greater than 10 Scm.sup.-1.

Thermal casting process for the preparation of anisotropic membranes and the resultant membrane

DOEpatents

Caneba, Gerard T. M.; Soong, David S.

1987-01-01

A method for providing anisotropic polymer membranes from a binary polymer/solvent solution using a thermal inversion process. A homogeneous binary solution is cast onto a support and cooled in such a way as to provide a differential in cooling rate across the thickness of the resulting membrane sheet. Isotropic or anisotropic structures of selected porosities can be produced, depending on the initial concentration of polymer in the selected solvent and on the extent of the differential in cooling rate. This differential results in a corresponding gradation in pore size. The method may be modified to provide a working skin by applying a rapid, high-temperature pulse to redissolve a predetermined thickness of the membrane at one of its faces and then freezing the entire structure.

Thermal casting process for the preparation of membranes

DOEpatents

Caneba, G.T.M.; Soong, D.S.

1985-07-10

Disclosed is a method for providing anisotropic polymer membrane from a binary polymer/solvent solution using a thermal inversion process. A homogeneous binary solution is cast onto a support and cooled in such a way as to provide a differential in cooling rate across the thickness of the resulting membrane sheet. Isotropic or anisotropic structures of selected porosities can be produced, depending on the initial concentration of polymer in the selected solvent and on the extent of the differential in cooling rate. This differential results in a corresponding gradation in pore size. The method may be modified to provide a working skin by applying a rapid, high-temperature pulse to redissolve a predetermined thickness of the membrane at one of its faces and then freezing the entire structure.

Biodegradable starch-based polymeric materials

NASA Astrophysics Data System (ADS)

Suvorova, Anna I.; Tyukova, Irina S.; Trufanova, Elena I.

2000-05-01

The effects of low-molecular-weight additives, temperature and mechanical action on the structure and properties of starch are discussed. Special attention is given to mixtures of starch with synthetic polymers, e.g., co-polymers of ethylene with vinyl acetate, vinyl alcohol, acrylic acid, cellulose derivatives and other natural polymers. These mixtures can be used in the development of novel environmentally safe materials (films, coatings, packaging materials) and various articles for short-term use. The bibliography includes 105 references.

Rheological Characterization of Molten Polymer-Drug Dispersions as a Predictive Tool for Pharmaceutical Hot-Melt Extrusion Processability.

PubMed

Van Renterghem, Jeroen; Vervaet, Chris; De Beer, Thomas

2017-11-01

The aim of this study was to investigate (i) the influence of drug solid-state (crystalline or dissolved in the polymer matrix) on the melt viscosity and (ii) the influence of the drug concentration, temperature and shear rate on polymer crystallization using rheological tests. Poly (ethylene oxide) (PEO) (100.000 g/mol) and physical mixtures (PM) containing 10-20-30-40% (w/w) ketoprofen or 10% (w/w) theophylline in PEO were rheologically characterized. Rheological tests were performed (frequency and temperature sweeps in oscillatory shear as well as shear-induced crystallization experiments) to obtain a thorough understanding of the flow behaviour and crystallization of PEO-drug dispersions. Theophylline did not dissolve in PEO as the complex viscosity (η*) of the drug-polymer mixture increased as compared to that of neat PEO. In contrast, ketoprofen dissolved in PEO and acted as a plasticizer, decreasing η*. Acting as a nucleating agent, theophylline induced the crystallization of PEO upon cooling from the melt. On the other hand, ketoprofen inhibited crystallization upon cooling. Moreover, higher concentrations of ketoprofen in the drug-polymer mixture increasingly inhibited polymer crystallization. However, shear-induced crystallization was observed for all tested mixtures containing ketoprofen. The obtained rheological results are relevant for understanding and predicting HME processability (e.g., barrel temperature selection) and downstream processing such as injection moulding (e.g., mold temperature selection).

Assessment of a Novel Ternary Eutectic Chloride Salt for Next Generation High-Temperature Sensible Heat Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vidal, Judith C; Mohan, Gowtham; Venkataraman, Mahesh

A novel ternary eutectic salt mixture for high-temperature sensible heat storage, composed of sodium chloride, potassium chloride and magnesium chloride (NaKMg-Cl) was developed based on a phase diagram generated with FactSage(R). The differential scanning calorimetry (DSC) technique was used to experimentally validate the predicted melting point of the ternary eutectic composition, which was measured as 387 degrees C, in good agreement with the prediction. The ternary eutectic was compared to two binary salts formulated based on prediction of the eutectic composition by FactSage, but unfortunately DSC measurements showed that neither binary salt composition was eutectic. Nonetheless, the measured thermo-physical propertiesmore » of the ternary and the two binary mixtures are compared. Liquid heat capacities of both the ternary and binary salts were determined by using DSC with sapphire as the standard reference. The average heat capacity of the ternary mixture was recorded as 1.18 J g-1 K-1. The mass loss of the molten eutectic salts was studied up to 1000 degrees C using a thermogravimetric analyser in nitrogen, argon and air. The results showed a significant mass loss due to vaporisation in an open system, particularly above 700 degrees C. However, simulation of mass loss in a closed system with an inert cover gas indicates storage temperatures above 700 degrees C may be feasible, and highlights the importance of the design of the storage tank system. In terms of storage material cost, the NaKMg-Cl mixture is approximately 4.5 USD/kWh, which is 60% cheaper than current state-of-the-art nitrate salt mixtures.« less

Molecular dynamics study of polysaccharides in binary solvent mixtures of an ionic liquid and water.

PubMed

Liu, Hanbin; Sale, Kenneth L; Simmons, Blake A; Singh, Seema

2011-09-01

Some ionic liquids (ILs) have great promise as effective solvents for biomass pretreatment, and there are several that have been reported that can dissolve large amounts of cellulose. The solubilized cellulose can then be recovered by addition of antisolvents, such as water or ethanol, and this regeneration process plays an important role in the subsequent enzymatic saccharification reactions and in the recovery of the ionic liquid. To date, little is known about the fundamental intermolecular interactions that drive the dissolution and subsequent regeneration of cellulose in complex mixtures of ionic liquids, water, and cellulose. To investigate these interactions, in this work, molecular dynamics (MD) simulations were carried out to study binary and ternary mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) with water and a cellulose oligomer. Simulations of a cellulose oligomer dissolved in three concentrations of binary mixtures of [C2mim][OAc] and water were used to represent the ternary system in the dissolution phase (high [C2mim][OAc] concentration) and present during the initial phase of the regeneration step (intermediate and low [C2mim][OAc] concentrations). The MD analysis of the structure and dynamics that exist in these binary and ternary mixtures provides information on the key intermolecular interactions between cellulose and [C2mim][OAc] that lead to dissolution of cellulose and the key intermolecular interactions in the intermediate states of cellulose precipitation as a function of water content in the cellulose/IL/water system. The analysis of this intermediate state provides new insight into the molecular driving forces present in this ternary system. © 2011 American Chemical Society

The onset of convection in a binary fluid mixture with temperature dependent viscosity and Coriolis force with Soret presence

NASA Astrophysics Data System (ADS)

Abidin, Nurul Hafizah Zainal; Mokhtar, Nor Fadzillah Mohd; Majid, Zanariah Abdul; Ghani, Siti Salwa Abd

2017-11-01

Temperature dependent viscosity and Coriolis force were applied to the steady Benard-Marangoni convection where the lower boundary of a horizontal layer of the binary mixture is heated from below and cooled from above. The purpose of this paper is to study in detail the onset of convection with these effects. Few cases of boundary conditions are studied which are rigid-rigid, rigid-free and free-free representing the lower-upper boundaries. A detailed numerical calculation of the marginal stability curves was performed by using the Galerkin method and it is showed that temperature dependent viscosity and Soret number destabilize the binary fluid layer system and Taylor number act oppositely.

Quantitative measurement of indomethacin crystallinity in indomethacin-silica gel binary system using differential scanning calorimetry and X-ray powder diffractometry.

PubMed

Pan, Xiaohong; Julian, Thomas; Augsburger, Larry

2006-02-10

Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) methods were developed for the quantitative analysis of the crystallinity of indomethacin (IMC) in IMC and silica gel (SG) binary system. The DSC calibration curve exhibited better linearity than that of XRPD. No phase transformation occurred in the IMC-SG mixtures during DSC measurement. The major sources of error in DSC measurements were inhomogeneous mixing and sampling. Analyzing the amount of IMC in the mixtures using high-performance liquid chromatography (HPLC) could reduce the sampling error. DSC demonstrated greater sensitivity and had less variation in measurement than XRPD in quantifying crystalline IMC in the IMC-SG binary system.

Bioethanol production optimization: a thermodynamic analysis.

PubMed

Alvarez, Víctor H; Rivera, Elmer Ccopa; Costa, Aline C; Filho, Rubens Maciel; Wolf Maciel, Maria Regina; Aznar, Martín

2008-03-01

In this work, the phase equilibrium of binary mixtures for bioethanol production by continuous extractive process was studied. The process is composed of four interlinked units: fermentor, centrifuge, cell treatment unit, and flash vessel (ethanol-congener separation unit). A proposal for modeling the vapor-liquid equilibrium in binary mixtures found in the flash vessel has been considered. This approach uses the Predictive Soave-Redlich-Kwong equation of state, with original and modified molecular parameters. The congeners considered were acetic acid, acetaldehyde, furfural, methanol, and 1-pentanol. The results show that the introduction of new molecular parameters r and q in the UNIFAC model gives more accurate predictions for the concentration of the congener in the gas phase for binary and ternary systems.

Picosecond solvation dynamics—A potential viewer of DMSO—Water binary mixtures

NASA Astrophysics Data System (ADS)

Banik, Debasis; Kundu, Niloy; Kuchlyan, Jagannath; Roy, Arpita; Banerjee, Chiranjib; Ghosh, Surajit; Sarkar, Nilmoni

2015-02-01

In this work, we have investigated the composition dependent anomalous behavior of dimethyl sulfoxide (DMSO)-water binary mixture by collecting the ultrafast solvent relaxation response around a well known solvation probe Coumarin 480 (C480) by using a femtosecond fluorescence up-conversion spectrometer. Recent molecular dynamics simulations have predicted two anomalous regions of DMSO-water binary mixture. Particularly, these studies encourage us to investigate the anomalies from experimental background. DMSO-water binary mixture has repeatedly given evidences of its dual anomalous nature in front of our systematic investigation through steady-state and time-resolved measurements. We have calculated average solvation times of C480 by two individual well-known methods, among them first one is spectral-reconstruction method and another one is single-wavelength measurement method. The results of both the methods roughly indicate that solvation time of C480 reaches maxima in the mole fraction of DMSO XD = 0.12-0.17 and XD = 0.27-0.35, respectively. Among them, the second region (XD = 0.27-0.35) is very common as most of the thermodynamic properties exhibit deviation in this range. Most probably, the anomalous solvation trend in this region is fully guided by the shear viscosity of the medium. However, the first region is the most interesting one. In this region due to formation of strongly hydrogen bonded 1DMSO:2H2O complexes, hydration around the probe C480 decreases, as a result of which solvation time increases.

Dielectric Studies on Binary Mixtures of Diethyl Ether (DEE) in Polar Solvents

NASA Astrophysics Data System (ADS)

Pradhan, S. K.; Dash, S. K.; Swain, M. D.; Swain, B. B.

2011-11-01

Dielectric constant (ɛ) of diethylether (DEE) in binary mixtures with four polar solvents such as n-butanl, i-butanol, t-butanol and tolune has been measured at 455 kHz and at a temperature 303.15 K. The refractive indices were measured at a regulated temperature by Pulfrich refractometer at sodium D-line. The data is used to evaluate mutual correlation factor gab, excess molar polarization and excess free energy of mixing ΔGab by using Winkelmann-Quitzsch equation for binary mixtures to asses the suitability of the polar solvents as modifiers. The trend of variation for these parameters exhibit marked dependence on the nature of alcohols. Diethylether is one of the solvent extractant used for the extraction and separation of zirconium and hafnium in reactor technology. The extractant is blended with appropriate polar modifiers for greater dispersal and more rapid phase disengagement. This facilitates in the elimination of the third organo-aqueous phase containing some of the metal ions. As such the study of molecular interaction among the component molecules has been undertaken in these binary mixtures using the dielectric route. The interaction parameters such as mutual correlation factor gab is found to be less than one in all alcohols, while it is negative in toluene upto 0.7 DEE molefraction and thereafter becoming positive. The nature of variation of the excess miolar polarization ΔP and excess free energy of mixing Gab tends to support the assessment of gab to choose a suitable polar modifier.

Colorometric detection of water using MOF-polymer films and composites

DOEpatents

Allendorf, Mark D.; Talin, Albert Alec

2016-05-24

A method including exposing a mixture of a porous metal organic framework (MOF) and a polymer to a predetermined molecular species, wherein the MOF has an open metal site for the predetermined molecular species and the polymer has a porosity for the predetermined molecular species; and detecting a color change of the MOF in the presence of the predetermined molecular species. A method including combining a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species. An article of manufacture including a mixture of a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species.

Persistent activation of DNA damage signaling in response to complex mixtures of PAHs in air particulate matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarvis, Ian W.H., E-mail: Ian.Jarvis@ki.se; Bergvall, Christoffer, E-mail: Christoffer.Bergvall@anchem.su.se; Bottai, Matteo, E-mail: Matteo.Bottai@ki.se

2013-02-01

Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are present in air particulate matter (PM) and have been associated with many adverse human health effects including cancer and respiratory disease. However, due to their complexity, the risk of exposure to mixtures is difficult to estimate. In the present study the effects of binary mixtures of benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) and complex mixtures of PAHs in urban air PM extracts on DNA damage signaling was investigated. Applying a statistical model to the data we observed a more than additive response for binary mixtures of BP and DBP on activation of DNAmore » damage signaling. Persistent activation of checkpoint kinase 1 (Chk1) was observed at significantly lower BP equivalent concentrations in air PM extracts than BP alone. Activation of DNA damage signaling was also more persistent in air PM fractions containing PAHs with more than four aromatic rings suggesting larger PAHs contribute a greater risk to human health. Altogether our data suggests that human health risk assessment based on additivity such as toxicity equivalency factor scales may significantly underestimate the risk of exposure to complex mixtures of PAHs. The data confirms our previous findings with PAH-contaminated soil (Niziolek-Kierecka et al., 2012) and suggests a possible role for Chk1 Ser317 phosphorylation as a biological marker for future analyses of complex mixtures of PAHs. -- Highlights: ► Benzo[a]pyrene (BP), dibenzo[a,l]pyrene (DBP) and air PM PAH extracts were compared. ► Binary mixture of BP and DBP induced a more than additive DNA damage response. ► Air PM PAH extracts were more potent than toxicity equivalency factor estimates. ► Larger PAHs (> 4 rings) contribute more to the genotoxicity of PAHs in air PM. ► Chk1 is a sensitive marker for persistent activation of DNA damage signaling from PAH mixtures.« less

Sustained induction of cytochrome P4501A1 in human hepatoma cells by co-exposure to benzo[a]pyrene and 7H-dibenzo[c,g]carbazole underlies the synergistic effects on DNA adduct formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gábelová, Alena, E-mail: alena.gabelova@savba.sk; Poláková, Veronika; Prochazka, Gabriela

To gain a deeper insight into the potential interactions between individual aromatic hydrocarbons in a mixture, several benzo[a]pyrene (B[a]P) and 7H-dibenzo[c,g]carbazole (DBC) binary mixtures were studied. The biological activity of the binary mixtures was investigated in the HepG2 and WB-F344 liver cell lines and the Chinese hamster V79 cell line that stably expresses the human cytochrome P4501A1 (hCYP1A1). In the V79 cells, binary mixtures, in contrast to individual carcinogens, caused a significant decrease in the levels of micronuclei, DNA adducts and gene mutations, but not in cell survival. Similarly, a lower frequency of micronuclei and levels of DNA adducts weremore » found in rat liver WB-F344 cells treated with a binary mixture, regardless of the exposure time. The observed antagonism between B[a]P and DBC may be due to an inhibition of Cyp1a1 expression because cells exposed to B[a]P:DBC showed a decrease in Cyp1a1 mRNA levels. In human liver HepG2 cells exposed to binary mixtures for 2 h, a reduction in micronuclei frequency was also found. However, after a 24 h treatment, synergism between B[a]P and DBC was determined based on DNA adduct formation. Accordingly, the up-regulation of CYP1A1 expression was detected in HepG2 cells exposed to B[a]P:DBC. Our results show significant differences in the response of human and rat cells to B[a]P:DBC mixtures and stress the need to use multiple experimental systems when evaluating the potential risk of environmental pollutants. Our data also indicate that an increased expression of CYP1A1 results in a synergistic effect of B[a]P and DBC in human cells. As humans are exposed to a plethora of noxious chemicals, our results have important implications for human carcinogenesis. - Highlights: • B[a]P:DBC mixtures were less genotoxic in V79MZh1A1 cells than B[a]P and DBC alone. • An antagonism between B[a]P and DBC was determined in rat liver WB-F344 cells. • The inhibition of CYP1a1 expression by B[a]P:DBC mixture underlies this antagonism. • A synergism between B[a]P and DBC was detected in human liver HepG2 cells. • The up-regulation of CYP1A1 expression was found in B[a]P:DBC-exposed HepG2 cells.« less

Measuring and modeling of binary mixture effects of pharmaceuticals and nickel on cell viability/cytotoxicity in the human hepatoma derived cell line HepG2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudzok, S., E-mail: susanne.rudzok@ufz.d; Schlink, U., E-mail: uwe.schlink@ufz.d; Herbarth, O., E-mail: olf.herbarth@medizin.uni-leipzig.d

2010-05-01

The interaction of drugs and non-therapeutic xenobiotics constitutes a central role in human health risk assessment. Still, available data are rare. Two different models have been established to predict mixture toxicity from single dose data, namely, the concentration addition (CA) and independent action (IA) model. However, chemicals can also act synergistic or antagonistic or in dose level deviation, or in a dose ratio dependent deviation. In the present study we used the MIXTOX model (EU project ENV4-CT97-0507), which incorporates these algorithms, to assess effects of the binary mixtures in the human hepatoma cell line HepG2. These cells possess a liver-likemore » enzyme pattern and a variety of xenobiotic-metabolizing enzymes (phases I and II). We tested binary mixtures of the metal nickel, the anti-inflammatory drug diclofenac, and the antibiotic agent irgasan and compared the experimental data to the mathematical models. Cell viability was determined by three different methods the MTT-, AlamarBlue (registered) and NRU assay. The compounds were tested separately and in combinations. We could show that the metal nickel is the dominant component in the mixture, affecting an antagonism at low-dose levels and a synergism at high-dose levels in combination with diclofenac or irgasan, when using the NRU and the AlamarBlue assay. The dose-response surface of irgasan and diclofenac indicated a concentration addition. The experimental data could be described by the algorithms with a regression of up to 90%, revealing the HepG2 cell line and the MIXTOX model as valuable tool for risk assessment of binary mixtures for cytotoxic endpoints. However the model failed to predict a specific mode of action, the CYP1A1 enzyme activity.« less

Studying of crystal growth and overall crystallization of naproxen from binary mixtures.

PubMed

Kaminska, E; Madejczyk, O; Tarnacka, M; Jurkiewicz, K; Kaminski, K; Paluch, M

2017-04-01

Broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC) were applied to investigate the molecular dynamics and phase transitions in binary mixtures composed of naproxen (NAP) and acetylated saccharides: maltose (acMAL) and sucrose (acSUC). Moreover, the application of BDS method and optical microscopy enabled us to study both crystallization kinetics and crystal growth of naproxen from the solid dispersions with the highest content of modified carbohydrates (1:5wt ratio). It was found that the activation barriers of crystallization estimated from dielectric measurements are completely different for both studied herein mixtures. Much higher E a (=205kJ/mol) was obtained for NAP-acMAL solid dispersion. It is probably due to simultaneous crystallization of both components of the mixture. On the other hand, lower value of E a in the case of NAP-acSUC solid dispersion (81kJ/mol) indicated, that naproxen is the only crystallizing compound. This hypothesis was confirmed by X-ray diffraction studies. We also suggested that specific intermolecular dipole-dipole interactions between active substance and excipient may be an alternative explanation for the difference between activation barrier obtained for NAP-acMAL and NAP-acSUC binary mixtures. Furthermore, optical measurements showed that the activation energy for crystal growth of naproxen increases in binary mixtures. They also revealed that both excipients: acMAL and acSUC move the temperature of the maximum of crystal growth towards lower temperatures. Interestingly, this maximum occurs for nearly the same structural relaxation time, which is a good approximation of viscosity, for all samples. Finally, it was also noticed that although naproxen crystallizes to the same polymorphic form in both systems, there are some differences in morphology of obtained crystals. Thus, the observed behavior may have a significant impact on the bioavailability and dissolution rate of API produced in that way. Copyright © 2016 Elsevier B.V. All rights reserved.

Four Derivative Spectrophotometric Methods for the Simultaneous Determination of Carmoisine and Ponceau 4R in Drinks and Comparison with High Performance Liquid Chromatography

PubMed Central

Turak, Fatma; Dinç, Mithat; Dülger, Öznur; Özgür, Mahmure Ustun

2014-01-01

Four simple, rapid, and accurate spectrophotometric methods were developed for the simultaneous determination of two food colorants, Carmoisine (E122) and Ponceau 4R (E124), in their binary mixtures and soft drinks. The first method is based on recording the first derivative curves and determining each component using the zero-crossing technique. The second method uses the first derivative of ratio spectra. The ratio spectra are obtained by dividing the absorption spectra of the binary mixture by that of one of the components. The third method, derivative differential procedure, is based on the measurement of difference absorptivities derivatized in first order of solution of drink samples in 0,1 N NaOH relative to that of an equimolar solution in 0,1 N HCl at wavelengths of 366 and 451 nm for Carmoisine and Ponceau 4R, respectively. The last method, based on the compensation method is presented for derivative spectrophotometric determination of E122 and E124 mixtures with overlapping spectra. By using ratios of the derivative maxima, the exact compensation of either component in the mixture can be achieved, followed by its determination. These proposed methods have been successfully applied to the binary mixtures and soft drinks and the results were statistically compared with the reference HPLC method (NMKL 130). PMID:24672549

Determination of thermodynamic properties of isotactic poly(1-butene) at infinite dilution using density and inverse gas chromatography.

PubMed

Kozłowska, Marta Karolina; Domańska, Urszula; Lempert, Małgorzata; Rogalski, Marek

2005-03-18

The partial molar volumes, V1(M), and the molar volume of isotactic crystalline low-molecular-weight poly(1-butene), iPBu-1, V1, have been calculated from the measured density of {iPBu-1 + solvent (n-hexane, n-heptane, n-nonane, n-decane, p-xylene, cyclohexane and chloroform)} systems. Some of the thermodynamic quantities were also obtained for the iPBu-1 with eight hydrocarbons (n-octane, n-decane, n-undecane, n-dodecane, n-tridecane, o-xylene, m-xylene, p-xylene) by the method of inverse gas chromatography at various temperatures. The weight fraction activity coefficients of the solvent at infinite dilution, omega2(infinity) and the Flory-Huggins thermodynamic interaction parameters, chi21(infinity), between polymer and solvents were determined. The partial molar free energy, deltaG2(infinity), the partial molar heat of mixing, deltaH2(infinity), at infinite dilution and the polymer solubility parameter, delta1, were calculated. Additionally, the (solid + liquid) binary mixtures equilibria, SLE, of iPBu-1 with three hydrocarbons (n-octane, n-decane and m-xylene) were studied by a dynamic method. By performing these experiments over a large concentration range, the T-x phase diagrams of the polymer-solvent systems were constructed. The excess Gibbs energy models were used to describe the nonideal behaviour of the liquid phase. The omega2(infinity) were determined from the solubility measurements and were predicted by using the UNIFAC FV model.

Detecting phase separation of freeze-dried binary amorphous systems using pair-wise distribution function and multivariate data analysis.

PubMed

Chieng, Norman; Trnka, Hjalte; Boetker, Johan; Pikal, Michael; Rantanen, Jukka; Grohganz, Holger

2013-09-15

The purpose of this study is to investigate the use of multivariate data analysis for powder X-ray diffraction-pair-wise distribution function (PXRD-PDF) data to detect phase separation in freeze-dried binary amorphous systems. Polymer-polymer and polymer-sugar binary systems at various ratios were freeze-dried. All samples were analyzed by PXRD, transformed to PDF and analyzed by principal component analysis (PCA). These results were validated by differential scanning calorimetry (DSC) through characterization of glass transition of the maximally freeze-concentrate solute (Tg'). Analysis of PXRD-PDF data using PCA provides a more clear 'miscible' or 'phase separated' interpretation through the distribution pattern of samples on a score plot presentation compared to residual plot method. In a phase separated system, samples were found to be evenly distributed around the theoretical PDF profile. For systems that were miscible, a clear deviation of samples away from the theoretical PDF profile was observed. Moreover, PCA analysis allows simultaneous analysis of replicate samples. Comparatively, the phase behavior analysis from PXRD-PDF-PCA method was in agreement with the DSC results. Overall, the combined PXRD-PDF-PCA approach improves the clarity of the PXRD-PDF results and can be used as an alternative explorative data analytical tool in detecting phase separation in freeze-dried binary amorphous systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Polymer collapse in miscible good solvents is a generic phenomenon driven by preferential adsorption

PubMed Central

Mukherji, Debashish; Marques, Carlos M.; Kremer, Kurt

2014-01-01

Water and alcohol, such as methanol or ethanol, are miscible and, individually, good solvents for poly(N-isopropylacrylamide) (PNIPAm), but this polymer precipitates in water–alcohol mixtures. The intriguing behaviour of solvent mixtures that cannot dissolve a given polymer or a given protein, while the same macromolecule dissolves well in each of the cosolvents, is called cononsolvency. It is a widespread phenomenon, relevant for many formulation steps in the physicochemical and pharmaceutical industry, that is usually explained by invoking specific chemical details of the mixtures: as such, it has so far eluded any generic explanation. Here, by using a combination of simulations and theory, we present a simple and universal treatment that requires only the preferential interaction of one of the cosolvents with the polymer. The results show striking quantitative agreement with experiments and chemically specific simulations, opening a new perspective towards an operational understanding of macromolecular solubility. PMID:25216245

Polydispersity effects in colloid-polymer mixtures.

PubMed

Liddle, S M; Narayanan, T; Poon, W C K

2011-05-18

We study phase separation and transient gelation experimentally in a mixture consisting of polydisperse colloids (polydispersity: ≈ 6%) and non-adsorbing polymers, where the ratio of the average size of the polymer to that of the colloid is ≈ 0.062. Unlike what has been reported previously for mixtures with somewhat lower colloid polydispersity (≈ 5%), the addition of polymers does not expand the fluid-solid coexistence region. Instead, we find a region of fluid-solid coexistence which has an approximately constant width but an unexpected re-entrant shape. We detect the presence of a metastable gas-liquid binodal, which gives rise to two-stepped crystallization kinetics that can be rationalized as the effect of fractionation. Finally, we find that the separation into multiple coexisting solid phases at high colloid volume fractions predicted by equilibrium statistical mechanics is kinetically suppressed before the system reaches dynamical arrest.

An experimental study of adsorption interference in binary mixtures flowing through activated carbon

NASA Technical Reports Server (NTRS)

Madey, R.; Photinos, P. J.

1983-01-01

The isothermal transmission through activated carbon adsorber beds at 25 C of acetaldehyde-propane and acetylene-ethane mixtures in a helium carrier gas was measured. The inlet concentration of each component was in the range between 10 ppm and 500 ppm. The constant inlet volumetric flow rate was controlled at 200 cc (STP)/min in the acetaldehyde-propane experiments and at 50 cc (STP)/min in the acetaldehyde-ethane experiments. Comparison of experimental results with the corresponding single-component experiments under similar conditions reveals interference phenomena between the components of the mixtures as evidenced by changes in both the adsorption capacity and the dispersion number. Propane was found to displace acetaldehyde from the adsorbed state. The outlet concentration profiles of propane in the binary mixtures tend to become more diffuse than the corresponding concentration profiles of the one-component experiments. Similar features were observed with mixtures of acetylene and ethane; however, the displacement of acetylene by ethane is less pronounced.

Efficient capture of SO2 by a binary mixture of caprolactam tetrabutyl ammonium bromide ionic liquid and water.

PubMed

Duan, Erhong; Guo, Bin; Zhang, Miaomiao; Guan, Yanan; Sun, Hua; Han, Jing

2011-10-30

The solubility of SO(2) in a binary mixture of water and caprolactam tetrabutyl ammonium bromide ionic liquid (CPL-TBAB IL) was investigated. Though the ionic liquid and water were fully miscible, a phase separation occurred when SO(2) was introduced into the mixture. The SO(2) concentrated in the lower layer, and it could be released by heating the solution under reduced pressure (382.2K, 10.1 kPa). After desorption, the mixture could be reused to absorb SO(2). It was found that SO(2) acts as a switch to cause the water and CPL-TBAB IL to phase separate, and the mechanics of this phase separation process was studied by gas chromatography-mass spectrometry, fourier transform-infrared spectroscopy and Karl-Fisher titration. The absorption and desorption of SO(2) in the CPL-TBAB/water mixtures were reversible. Copyright © 2011 Elsevier B.V. All rights reserved.

Cosolvent effect on the dynamics of water in aqueous binary mixtures

NASA Astrophysics Data System (ADS)

Zhang, Xia; Zhang, Lu; Jin, Tan; Zhang, Qiang; Zhuang, Wei

2018-04-01

Water rotational dynamics in the mixtures of water and amphiphilic molecules, such as acetone and dimethyl sulfoxide (DMSO), measured by femtosecond infrared, often vary non-monotonically as the amphiphilic molecule's molar fraction changes from 0 to 1. Recent study has attributed the non-ideal water rotation with concentration in DMSO-water mixtures to different microscopic hydrophilic-hydrophobic segregation structure in water-rich and water-poor mixtures. Interestingly, the acetone molecule has very similar molecular structure to DMSO, but the extremum of the water rotational time in the DMSO-water mixtures significantly shifts to lower concentration and the rotation of water is much faster than those in acetone-water mixtures. The simulation results here shows that the non-ideal rotational dynamics of water in both mixtures are due to the frame rotation during the interval of hydrogen bond (HB) switchings. A turnover of the frame rotation with concentration takes place as the structure transition of mixture from the hydrogen bond percolation structure to the hydrophobic percolation structure. The weak acetone-water hydrogen bond strengthens the hydrophobic aggregation and accelerates the relaxation of the hydrogen bond, so that the structure transition takes places at lower concentration and the rotation of water is faster in acetone-water mixture than in DMSO-water mixture. A generally microscopic picture on the mixing effect on the water dynamics in binary aqueous mixtures is presented here.

Efficacy and safety of a biodegradable polymer sirolimus-eluting stent in primary percutaneous coronary intervention: a randomized controlled trial

PubMed Central

Li, Qiang; Tong, Zichuan; Wang, Lefeng; Zhang, Jianjun; Ge, Yonggui; Wang, Hongshi; Li, Weiming; Xu, Li; Ni, Zhuhua

2013-01-01

Introduction With long-term follow-up, whether biodegradable polymer drug-eluting stents (DES) is efficient and safe in primary percutaneous coronary intervention (PCI) remains a controversial issue. This study aims to assess the long-term efficacy and safety of DES in PCI for ST-segment elevation myocardial infarction (STEMI). Material and methods A prospective, randomized single-blind study with 3-year follow-up was performed to compare biodegradable polymer DES with durable polymer DES in 332 STEMI patients treated with primary PCI. The primary end point was major adverse cardiac events (MACE) at 3 years after the procedure, defined as the composite of cardiac death, recurrent infarction, and target vessel revascularization. The secondary end points included in-segment late luminal loss (LLL) and binary restenosis at 9 months and cumulative stent thrombosis (ST) event rates up to 3 years. Results The rate of the primary end points and the secondary end points including major adverse cardiac events, in-segment late luminal loss, binary restenosis, and cumulative thrombotic event rates were comparable between biodegradable polymer DES and durable polymer DES in these 332 STEMI patients treated with primary PCI at 3 years. Conclusions Biodegradable polymer DES has similar efficacy and safety profiles at 3 years compared with durable polymer DES in STEMI patients treated with primary PCI. PMID:24482648

Synthesis and characterization of ionomers as polymer electrolytes for energy conversion devices

NASA Astrophysics Data System (ADS)

Oh, Hyukkeun

Single-ion conducting electrolytes present a unique alternative to traditional binary salt conductors used in lithium-ion batteries. Secondary lithium batteries are considered as one of the leading candidates to replace the combustible engines in automotive technology, however several roadblocks are present which prevent their widespread commercialization. Power density, energy density and safety properties must be improved in order to enable the current secondary lithium battery technology to compete with existing energy technologies. It has been shown theoretically that single-ion electrolytes can eliminate the salt concentration gradient and polarization loss in the cell that develops in a binary salt system, resulting in substantial improvements in materials utilization for high power and energy densities. While attempts to utilize single-ion conducting electrolytes in lithium-ion battery systems have been made, the low ionic conductivities prevented the successful operation of the battery cells in ambient conditions. This work focuses on designing single-ion conducting electrolytes with high ionic conductivities and electrochemical and mechanical stability which enables the stable charge-discharge performance of battery cells. Perfluorosulfonate ionomers are known to possess exceptionally high ionic conductivities due to the electron-withdrawing effect caused by the C-F bonds which stabilizes the negative charge of the anion, leading to a large number of free mobile cations. The effect of perfluorinated sulfonic acid side chains on transport properties of proton exchange membrane polymers was examinated via a comparison of three ionomers, having different side chain structures and a similar polymer backbone. The three different side chain structures were aryl-, pefluoro alkyl-, and alkyl-sulfonic acid groups, respectively. All ionomers were synthesized and characterized by 1H and 19F NMR. A novel ionomer synthesized with a pendant perfluorinated sulfonic acid group and a poly(ether ether ketone) backbone showed the highest proton conductivity and proton diffusion coefficient among the three ionomers, demonstrating the effect of the perfluorinated side chains. The proton conductivity of the novel ionomer was comparable to that of Nafion over a wide humidity range and temperature. A lithium perfluorosulfonate ionomer based on aromatic poly(arylene ether)s with pendant lithium perfluoroethyl sulfonates was prepared by ion exchange of the perlfuorosulfonic acid ionomer, and subsequently incoroporated into a lithium-ion battery cell as a single-ion conducting electrolyte. The microporous polymer film saturated with organic carbonates exhibited a nearly unity Li + transfer number, high ionic conductivity (e.g. > 10-3 S m-1 at room temperature) over a wide range of temperatures, high electrochemical stability, and excellent mechanical properties. Excellent cyclability with almost identical charge and discharge capacities have been demonstrated at ambient temperature in the batteries assembled from the prepared single-ion conductors. The mechanical stability of the polymer film was attributed to the rigid polymer backbone which was largely unaffected by the presence of plasticizing organic solvents, while the porous channels with high concentration of the perfluorinated side chains resulted in high ionic conductivity. The expected high charge-rate performance was not achieved, however, due to the high interfacial impedance present between the polymer electrolyte and the electrodes. Several procedural modifications were employed in order to decrease the interfacial impedance of the battery cell. The poly(arylene ether) based ionomer was saturated with an ionic liquid mixture, in order to explore the possibility of its application as a safe, inflammable electrolyte. A low-viscosity ionic liquid with high ionic conductivity, 1-butyl-3-methylimidazolium thiocyanate which has never been successfully utilized as an electrolyte for lithium-ion batteries was incorporated into a battery cell as a solvent mixture with propylene carbonate and lithium bis(trifluoromethane)sulfonimide impregnated in a free-standing hybrid electrolyte film. Outstanding ionic conductivity was achieved and the lithium half cell comprising a LTO cathode and a lithium metal anode separated by the solid polymer electrolyte showed good cyclability at room temperature and even at 0°C. The presence of a sufficient amount of propylene carbonate, which resulted in flammability of the polymer electrolyte, was discovered to be critical in the electrochemical stability of the polymer electrolyte.

Nonlinear optical imaging for sensitive detection of crystals in bulk amorphous powders.

PubMed

Kestur, Umesh S; Wanapun, Duangporn; Toth, Scott J; Wegiel, Lindsay A; Simpson, Garth J; Taylor, Lynne S

2012-11-01

The primary aim of this study was to evaluate the utility of second-order nonlinear imaging of chiral crystals (SONICC) to quantify crystallinity in drug-polymer blends, including solid dispersions. Second harmonic generation (SHG) can potentially exhibit scaling with crystallinity between linear and quadratic depending on the nature of the source, and thus, it is important to determine the response of pharmaceutical powders. Physical mixtures containing different proportions of crystalline naproxen and hydroxyl propyl methyl cellulose acetate succinate (HPMCAS) were prepared by blending and a dispersion was produced by solvent evaporation. A custom-built SONICC instrument was used to characterize the SHG intensity as a function of the crystalline drug fraction in the various samples. Powder X-ray diffraction (PXRD) and Raman spectroscopy were used as complementary methods known to exhibit linear scaling. SONICC was able to detect crystalline drug even in the presence of 99.9 wt % HPMCAS in the binary mixtures. The calibration curve revealed a linear dynamic range with a R(2) value of 0.99 spanning the range from 0.1 to 100 wt % naproxen with a root mean square error of prediction of 2.7%. Using the calibration curve, the errors in the validation samples were in the range of 5%-10%. Analysis of a 75 wt % HPMCAS-naproxen solid dispersion with SONICC revealed the presence of crystallites at an earlier time point than could be detected with PXRD and Raman spectroscopy. In addition, results from the crystallization kinetics experiment using SONICC were in good agreement with Raman spectroscopy and PXRD. In conclusion, SONICC has been found to be a sensitive technique for detecting low levels (0.1% or lower) of crystallinity, even in the presence of large quantities of a polymer. Copyright © 2012 Wiley-Liss, Inc.

Study of excess dielectric properties and Kirkwood correlation parameter of binary mixtures of benzaldehyde and methanol at different temperatures

NASA Astrophysics Data System (ADS)

Shah, N. S.; Vankar, H. P.; Rana, V. A.

2018-05-01

Static permittivity (ɛ0) and permittivity at optical frequency (ɛ∞) of the Benzaldehyde (BZ), Methanol (MeOH) and their binary mixtures were measured in the temperature range from 293.15 K to 323.15 K (in the interval of 10 K). From the ɛ0 and ɛ∞ other parameters such as effective Kirkwood correlation factor (geff), corrective Kirkwood correction factor (gf), Bruggman factor (fB), excess permittivity (ɛ0E ) and permittivity at optical frequency (ɛ∞E ) were evaluated.

Proteomic analysis of a model fish species exposed to individual pesticides and a binary mixture--Presentation

EPA Science Inventory

Pesticides are nearly ubiquitous in surface waters of the United States, where they often are found as mixtures. The molecular mechanisms underlying the toxic effects of sub-lethal exposure to pesticides as both individual and mixtures are unclear. The current work aims to ident...

Extracting alcohols from aqueous solutions. [USDOE patent application

DOEpatents

Compere, A.L.; Googin, J.M.; Griffith, W.L.

1981-12-02

The objective is to provide an efficient process for extracting alcohols in aqueous solutions into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. This is done by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5-18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is then mixed with one or more of a group of polyoxyalkylene polymers to extract the alcohol into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

An odorant congruent with a colour cue is selectively perceived in an odour mixture.

PubMed

Arao, Mari; Suzuki, Maya; Katayama, Jun'ich; Akihiro, Yagi

2012-01-01

Odour identification can be influenced by colour cues. This study examined the mechanism underlying this colour context effect. We hypothesised that a specific odour component congruent with a colour would be selectively perceived in preference to another odour component in a binary odour mixture. We used a ratio estimation method under two colour conditions, a binary odour mixture (experiment 1) and single chemicals presented individually (experiment 2). Each colour was congruent with one of the odour components. Participants judged the perceived mixture ratio in each odour container on which a colour patch was pasted. An influence of colour was not observed when the odour stimulus did not contain the odour component congruent with the colour (experiment 2); however, the odour component congruent with the colour was perceived as more dominant when the odour stimulus did contain the colour-congruent odorant (experiment 1). This pattern indicates that a colour-congruent odour component is selectively perceived in an odour mixture. This finding suggests that colours can enhance the perceptual representation of the colour-associated component in an odour mixture.

Observation of vapor bubble of non-azeotropic binary mixture in microgravity with a two-wavelength interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abe, Yoshiyuki; Iwasaki, Akira

1999-07-01

Although non-azeotropic mixtures are considered to be promising working fluids in advanced energy conversion systems, the primary technical problems in the heat transfer degradation in phase change processes cause economical handicap to wide-spread applications. The boiling behavior of mixtures still remains a number of basic questions being not answered yet, and the present authors believe that the most essential information for the boiling process in non-azeotropic mixtures is how temperature and concentration profiles are developed around the bubbles. The present study attempts at understanding fundamental heat and mass transfer mechanisms in nucleate pool boiling of non-azeotropic binary mixtures, and withmore » the knowledge to develop a passive boiling heat transfer enhancement eventually. To this end, the authors have employed microgravity environment for rather detailed observation around vapor bubbles in the course of boiling inception and bubble growth. A two-wavelength Mach-Zehnder interferometer has been developed, which withstands mechanical shock caused by gravity change from very low gravity of the order of 10{sup {minus}5} g to relatively high gravity of approximately 8 g exposed during deceleration period. A series of experiments on single vapor bubbles for CFC113 single component and CFC12/CFC112 non-azeotropic binary mixture have been conducted under a high quality microgravity conditions available in 10-second free-fall facility of Japan Microgravity Center (JAMIC). The results for single component liquid showed a strong influence due to Marangoni effect caused by the temperature profile around the bubble. The results for non-azeotropic binary mixture showed, however, considerably different behavior from single component liquid. Both temperature and concentration profiles around a single vapor bubble were evaluated from the interferograms. The temperature and concentration layers established around the bubbles were nearly one order of magnitude larger than those predicted by thermal diffusion and mass diffusion. The temperature and concentration profiles evaluated from the present experiments suggest the role of Marangoni effects due to both concentration profile and temperature profile around the bubble interface.« less

Finite-Size Effects of Binary Mutual Diffusion Coefficients from Molecular Dynamics

PubMed Central

2018-01-01

Molecular dynamics simulations were performed for the prediction of the finite-size effects of Maxwell-Stefan diffusion coefficients of molecular mixtures and a wide variety of binary Lennard–Jones systems. A strong dependency of computed diffusivities on the system size was observed. Computed diffusivities were found to increase with the number of molecules. We propose a correction for the extrapolation of Maxwell–Stefan diffusion coefficients to the thermodynamic limit, based on the study by Yeh and Hummer (J. Phys. Chem. B, 2004, 108, 15873−15879). The proposed correction is a function of the viscosity of the system, the size of the simulation box, and the thermodynamic factor, which is a measure for the nonideality of the mixture. Verification is carried out for more than 200 distinct binary Lennard–Jones systems, as well as 9 binary systems of methanol, water, ethanol, acetone, methylamine, and carbon tetrachloride. Significant deviations between finite-size Maxwell–Stefan diffusivities and the corresponding diffusivities at the thermodynamic limit were found for mixtures close to demixing. In these cases, the finite-size correction can be even larger than the simulated (finite-size) Maxwell–Stefan diffusivity. Our results show that considering these finite-size effects is crucial and that the suggested correction allows for reliable computations. PMID:29664633

Effect of genetic algorithm as a variable selection method on different chemometric models applied for the analysis of binary mixture of amoxicillin and flucloxacillin: A comparative study

NASA Astrophysics Data System (ADS)

Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

2016-03-01

Different chemometric models were applied for the quantitative analysis of amoxicillin (AMX), and flucloxacillin (FLX) in their binary mixtures, namely, partial least squares (PLS), spectral residual augmented classical least squares (SRACLS), concentration residual augmented classical least squares (CRACLS) and artificial neural networks (ANNs). All methods were applied with and without variable selection procedure (genetic algorithm GA). The methods were used for the quantitative analysis of the drugs in laboratory prepared mixtures and real market sample via handling the UV spectral data. Robust and simpler models were obtained by applying GA. The proposed methods were found to be rapid, simple and required no preliminary separation steps.

Nanocellular foam with solid flame retardant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Liang; Kelly-Rowley, Anne M.; Bunker, Shana P.

Prepare nanofoam by (a) providing an aqueous solution of a flame retardant dissolved in an aqueous solvent, wherein the flame retardant is a solid at 23.degree. C. and 101 kiloPascals pressure when in neat form; (b) providing a fluid polymer composition selected from a solution of polymer dissolved in a water-miscible solvent or a latex of polymer particles in a continuous aqueous phase; (c) mixing the aqueous solution of flame retardant with the fluid polymer composition to form a mixture; (d) removing water and, if present, solvent from the mixture to produce a polymeric composition having less than 74 weight-percentmore » flame retardant based on total polymeric composition weight; (e) compound the polymeric composition with a matrix polymer to form a matrix polymer composition; and (f) foam the matrix polymer composition into nanofoam having a porosity of at least 60 percent.« less

Direct micropatterning of polymer materials by ice mold

NASA Astrophysics Data System (ADS)

Yu, Xinhong; Xing, Rubo; Luan, Shifang; Wang, Zhe; Han, Yanchun

2006-10-01

Micropatterning of functional polymer materials by micromolding in capillaries (MIMIC) with ice mold is reported in this paper. Ice mold was selected due to its thaw or sublimation. Thus, the mold can be easily removed. Furthermore, the polymer solution did not react with, swell, or adhere to the ice mold, so the method is suitable for many kinds of materials (such as P3HT, PMMA Alq 3/PVK, PEDOT: PSS, PS, P2VP, etc.). Freestanding polymer microstructures, binary polymer pattern, and microchannels have been fabricated by the use of ice mold freely.

Computer Simulations of Ion Transport in Polymer Electrolyte Membranes.

PubMed

Mogurampelly, Santosh; Borodin, Oleg; Ganesan, Venkat

2016-06-07

Understanding the mechanisms and optimizing ion transport in polymer membranes have been the subject of active research for more than three decades. We present an overview of the progress and challenges involved with the modeling and simulation aspects of the ion transport properties of polymer membranes. We are concerned mainly with atomistic and coarser level simulation studies and discuss some salient work in the context of pure binary and single ion conducting polymer electrolytes, polymer nanocomposites, block copolymers, and ionic liquid-based hybrid electrolytes. We conclude with an outlook highlighting future directions.

Heat Transfer and Pressure Drop in Concentric Annular Flows of Binary Inert Gas Mixtures

NASA Technical Reports Server (NTRS)

Reid, R. S.; Martin, J. J.; Yocum, D. J.; Stewart, E. T.

2007-01-01

Studies of heat transfer and pressure drop of binary inert gas mixtures flowing through smooth concentric circular annuli, tubes with fully developed velocity profiles, and constant heating rate are described. There is a general lack of agreement among the constant property heat transfer correlations for such mixtures. No inert gas mixture data exist for annular channels. The intent of this study was to develop highly accurate and benchmarked pressure drop and heat transfer correlations that can be used to size heat exchangers and cores for direct gas Brayton nuclear power plants. The inside surface of the annular channel is heated while the outer surface of the channel is insulated. Annulus ratios range 0.5 < r* < 0.83. These smooth tube data may serve as a reference to the heat transfer and pressure drop performance in annuli, tubes, and channels having helixes or spacer ribs, or other surfaces.

Abnormal characteristics of binary molecular clusters in DMSO–ethanol mixtures under external electric fields

NASA Astrophysics Data System (ADS)

Wu, Zhiyan; Huang, Kama

2018-05-01

For the nonlinearly phenomena on the dielectric properties of dimethyl sulfoxide (DMSO)-ethanol mixtures under a low intensity microwave field, we propose a conjecture that there exist some abnormal molecular clusters. To interpret the mechanism of abnormal phenomena and confirm our conjecture about the existence of abnormal molecular clusters, an in-depth investigation about the structure evolutions of (DMSO)m(C2H5OH)n (m = 0-4; n = 0-4; m + n ≤ 4) molecular clusters induced by external electric fields has been given by using density functional theory. The results show that there exist some binary molecular clusters with large cluster radii in mixtures, and some of them are unstable under exposure of electric fields. It implies that the existence of certain abnormal molecular clusters in DMSO-ethanol mixtures results in their abnormality of dielectric properties.

The calculation of the phase equilibrium of the multicomponent hydrocarbon systems

NASA Astrophysics Data System (ADS)

Molchanov, D. A.

2018-01-01

Hydrocarbon mixtures filtration process simulation development has resulted in use of cubic equations of state of the van der Waals type to describe the thermodynamic properties of natural fluids under real thermobaric conditions. Binary hydrocarbon systems allow to simulate the fluids of different types of reservoirs qualitatively, what makes it possible to carry out the experimental study of their filtration features. Exploitation of gas-condensate reservoirs shows the possibility of existence of various two-phase filtration regimes, including self-oscillatory one, which occurs under certain values of mixture composition, temperature and pressure drop. Plotting of the phase diagram of the model mixture is required to determine these values. A software package to calculate the vapor-liquid equilibrium of binary systems using cubic equation of state of the van der Waals type has been created. Phase diagrams of gas-condensate model mixtures have been calculated.

A physicochemical investigation of ionic liquid mixtures† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc02931c Click here for additional data file.

PubMed Central

Clough, Matthew T.; Crick, Colin R.; Gräsvik, John; Niedermeyer, Heiko; Whitaker, Oliver P.

2015-01-01

Ionic liquids have earned the reputation of being ‘designer solvents’ due to the wide range of accessible properties and the degree of fine-tuning afforded by varying the constituent ions. Mixtures of ionic liquids offer the opportunity for further fine-tuning of properties. A broad selection of common ionic liquid cations and anions are employed to create a sample of binary and reciprocal binary ionic liquid mixtures, which are analysed and described in this paper. Physical properties such as the conductivity, viscosity, density and phase behaviour (glass transition temperatures) are examined. In addition, thermal stabilities of the mixtures are evaluated. The physical properties examined for these formulations are found to generally adhere remarkably closely to ideal mixing laws, with a few consistent exceptions, allowing for the facile prediction and control of properties of ionic liquid mixtures. PMID:29560198

Physical properties of new binary antiferroelectric liquid crystal mixtures

NASA Astrophysics Data System (ADS)

Fitas, Jakub; Jaworska-Gołąb, Teresa; Deptuch, Aleksandra; Tykarska, Marzena; Kurp, Katarzyna; Żurowska, Magdalena; Marzec, Monika

2018-02-01

Three newly prepared binary mixtures exhibiting chiral tilted smectic phases have been studied using differential scanning calorimetry, dielectric spectroscopy and electro-optic method, as well as X-ray diffraction. Broad temperature range of ferroelectric and antiferroelectric phases was detected in these mixtures and temperature dependence of spontaneous polarization, tilt angle and switching time were measured for all of them. It's occurred that all of the studied mixtures are orthoconic antiferroelectric liquid crystals. Based on the X-ray diffraction results, the temperature dependence of layer thickness in the paraelectric, ferroelectric and antiferroelectric phases was found. By using dielectric spectroscopy, Goldstone mode was identified in the ferroelectric phase, while antiphase fluctuations of azimuthal angle have been found in the antiferroelectric phase. Based on the results of the complementary methods, the transition temperatures were found as well as the order of the para-ferroelectric phase transition was determined as non-continuous one with critical parameter β equal to ca. 0.25.

Full-color tuning in binary polymer:perovskite nanocrystals organic-inorganic hybrid blends

NASA Astrophysics Data System (ADS)

Perulli, A.; Balena, A.; Fernandez, M.; Nedelcu, G.; Cretí, A.; Kovalenko, M. V.; Lomascolo, M.; Anni, M.

2018-04-01

The excellent optical and electronic properties of metal halide perovskites recently proposed these materials as interesting active materials for optoelectronic applications. In particular, the high color purity of perovskite colloidal nanocrystals (NCs) had recently motivated their exploration as active materials for light emitting diodes with tunable emission across the visible range. In this work, we investigated the emission properties of binary blends of conjugated polymers and perovskite NCs. We demonstrate that the emission color of the blends is determined by the superposition of the component photoluminescence spectra, allowing color tuning by acting on the blend relative composition. The use of two different polymers, two different perovskite NCs, and different blend compositions is exploited to tune the blend color in the blue-green, yellow-red, and blue-red ranges, including white light generation.

Testing the accuracy of correlations for multicomponent mass transport of adsorbed gases in metal-organic frameworks: diffusion of H2/CH4 mixtures in CuBTC.

PubMed

Keskin, Seda; Liu, Jinchen; Johnson, J Karl; Sholl, David S

2008-08-05

Mass transport of chemical mixtures in nanoporous materials is important in applications such as membrane separations, but measuring diffusion of mixtures experimentally is challenging. Methods that can predict multicomponent diffusion coefficients from single-component data can be extremely useful if these methods are known to be accurate. We present the first test of a method of this kind for molecules adsorbed in a metal-organic framework (MOF). Specifically, we examine the method proposed by Skoulidas, Sholl, and Krishna (SSK) ( Langmuir, 2003, 19, 7977) by comparing predictions made with this method to molecular simulations of mixture transport of H 2/CH 4 mixtures in CuBTC. These calculations provide the first direct information on mixture transport of any species in a MOF. The predictions of the SSK approach are in good agreement with our direct simulations of binary diffusion, suggesting that this approach may be a powerful one for examining multicomponent diffusion in MOFs. We also use our molecular simulation data to test the ideal adsorbed solution theory method for predicting binary adsorption isotherms and a method for predicting mixture self-diffusion coefficients.

A Functional Monomer Is Not Enough: Principal Component Analysis of the Influence of Template Complexation in Pre-Polymerization Mixtures on Imprinted Polymer Recognition and Morphology

PubMed Central

Golker, Kerstin; Karlsson, Björn C. G.; Rosengren, Annika M.; Nicholls, Ian A.

2014-01-01

In this report, principal component analysis (PCA) has been used to explore the influence of template complexation in the pre-polymerization phase on template molecularly imprinted polymer (MIP) recognition and polymer morphology. A series of 16 bupivacaine MIPs were studied. The ethylene glycol dimethacrylate (EGDMA)-crosslinked polymers had either methacrylic acid (MAA) or methyl methacrylate (MMA) as the functional monomer, and the stoichiometry between template, functional monomer and crosslinker was varied. The polymers were characterized using radioligand equilibrium binding experiments, gas sorption measurements, swelling studies and data extracted from molecular dynamics (MD) simulations of all-component pre-polymerization mixtures. The molar fraction of the functional monomer in the MAA-polymers contributed to describing both the binding, surface area and pore volume. Interestingly, weak positive correlations between the swelling behavior and the rebinding characteristics of the MAA-MIPs were exposed. Polymers prepared with MMA as a functional monomer and a polymer prepared with only EGDMA were found to share the same characteristics, such as poor rebinding capacities, as well as similar surface area and pore volume, independent of the molar fraction MMA used in synthesis. The use of PCA for interpreting relationships between MD-derived descriptions of events in the pre-polymerization mixture, recognition properties and morphologies of the corresponding polymers illustrates the potential of PCA as a tool for better understanding these complex materials and for their rational design. PMID:25391043

A functional monomer is not enough: principal component analysis of the influence of template complexation in pre-polymerization mixtures on imprinted polymer recognition and morphology.

PubMed

Golker, Kerstin; Karlsson, Björn C G; Rosengren, Annika M; Nicholls, Ian A

2014-11-10

In this report, principal component analysis (PCA) has been used to explore the influence of template complexation in the pre-polymerization phase on template molecularly imprinted polymer (MIP) recognition and polymer morphology. A series of 16 bupivacaine MIPs were studied. The ethylene glycol dimethacrylate (EGDMA)-crosslinked polymers had either methacrylic acid (MAA) or methyl methacrylate (MMA) as the functional monomer, and the stoichiometry between template, functional monomer and crosslinker was varied. The polymers were characterized using radioligand equilibrium binding experiments, gas sorption measurements, swelling studies and data extracted from molecular dynamics (MD) simulations of all-component pre-polymerization mixtures. The molar fraction of the functional monomer in the MAA-polymers contributed to describing both the binding, surface area and pore volume. Interestingly, weak positive correlations between the swelling behavior and the rebinding characteristics of the MAA-MIPs were exposed. Polymers prepared with MMA as a functional monomer and a polymer prepared with only EGDMA were found to share the same characteristics, such as poor rebinding capacities, as well as similar surface area and pore volume, independent of the molar fraction MMA used in synthesis. The use of PCA for interpreting relationships between MD-derived descriptions of events in the pre-polymerization mixture, recognition properties and morphologies of the corresponding polymers illustrates the potential of PCA as a tool for better understanding these complex materials and for their rational design.

Marangoni Effects in the Boiling of Binary Fluid Mixtures

NASA Technical Reports Server (NTRS)

Ahmed, Sayeed; Carey, Van P.; Motil, Brian

1996-01-01

Results of very recent experimental studies indicate that during nucleate boiling in some binary mixture, Marangoni effects augment the gravity driven flow of liquid towards the heated surface. With gravity present, it is impossible to separate the two effects. The reduced gravity environment gives an unique opportunity to explore th role of Marangoni effects on the boiling mechanisms free of gravitational body forces that obscure the role of such effects. However, recent experimental results suggest that under reduced gravity conditions, Marangoni effects is the dominant mechanism of vapor-liquid exchange at the surface for some binary mixture. To further explore such effects, experiments have been conducted with water/2-propanol mixtures at three different concentrations under normal gravity with different orientations of the heater surface and under reduce gravity aboard the DC-9 aircraft at NASA Lewis Research Center. The system pressure was sub atmospheric (approx. 8 kP at 1g(n)) and the bulk liquid temperature varied from low subcooling to near saturation. The molar concentrations of 2-propanol tested were 0.015, 0.025, and 0.1. Boiling curves were obtained both for high gravity (approx. 2g(n)) and reduce gravity (approx. 0.01g(n)). For each concentration of 2-propanol, the critical heat flux has been determined in the flight experiments only for reduced gravity conditions. Comparison of boiling curves and CHF obtained under l-g(n) an reduced gravity indicates that boiling mechanism in this mixtures is nearly independent of gravity. The results also indicate that the Marangoni mechanism is strong enough in these mixtures to sustain the boiling under reduced gravity conditions.

Effects of binary taste stimuli on the neural activity of the hamster chorda tympani

PubMed Central

1980-01-01

Binary mixtures of taste stimuli were applied to the tongue of the hamster and the reaction of the whole corda tympani was recorded. Some of the chemicals that were paired in mixtures (HCl, NH4Cl, NaCl, CaCl2, sucrose, and D-phenylalanine) have similar tastes to human and/or hamster, and/or common stimulatory effects on individual fibers of the hamster chorda tympani; other pairs of these chemicals have dissimilar tastes and/or distinct neural stimulatory effects. The molarity of each chemical with approximately the same effect on the activity of the nerve as 0.01 M NaCl was selected, and an established relation between stimulus concentration and response allowed estimation of the effect of a "mixture" of two concentrations of one chemical. Each mixture elicited a response that was smaller than the sum of the responses to its components. However, responses to some mixtures approached this sum, and responses to other mixtures closely approached the response to a "mixture" of two concentrations of one chemical. Responses of the former variety were generated by mixtures of an electrolyte and a nonelectrolyte and the latter by mixtures of two electrolytes or two nonelectrolytes. But, beyond the distinction between electrolytes and nonelectrolytes, the whole-nerve response to a mixture could not be predicted from the known neural or psychophysical effects of its components. PMID:7411114

Enhanced toxicity of binary mixtures of Bacillus thuringiensis subsp. israelensis and three essential oil major constituents to wild Anopheles sinensis (Diptera: Culicidae) and Aedes albopictus (Diptera: Culicidae).

PubMed

Chang, Kyu-Sik; Shin, E-Hyun; Yoo, Dae-Hyun; Ahn, Young-Joon

2014-07-01

An assessment was made of the toxicity of 12 insecticides and three essential oils as well as Bacillus thuringiensis subsp. israelensis (Bti) alone or in combination with the oil major constituents (E)-anethole (AN), (E) -cinnamaldehyde (CA), and eugenol (EU; 1:1 ratio) to third instars of bamboo forest-collected Aedes albopictus (Skuse) and rice paddy field-collected Anopheles sinensis Wiedemann. An. sinensis larvae were resistant to various groups of the tested insecticides. Based on 24-h LC50 values, binary mixtures of Bti and CA, AN, or EU were significantly more toxic against Ae. albopictus larvae (0.0084, 0.0134, and 0.0237 mg/liter) and An. sinensis larvae (0.0159, 0.0388, and 0.0541 mg/liter) than either Bti (1.7884 and 2.1681 mg/liter) or CA (11.46 and 18.56 mg/liter), AN (16.66 and 25.11 mg/liter), or EU (24.60 and 31.09 mg/liter) alone. As judged by cotoxicity coefficient (CC) and synergistic factor (SF), the three binary mixtures operated in a synergy pattern (CC, 140.7-368.3 and SF, 0.0007-0.0010 for Ae. albopictus; CC, 75.1-245.3 and SF, 0.0008-0.0017 for An. sinensis). Global efforts to reduce the level of highly toxic synthetic insecticides in the aquatic environment justify further studies on the binary mixtures of Bti and essential oil constituents described, in particular CA, as potential larvicides for the control of malaria vector mosquito populations.

Competitive adsorption of a binary CO2-CH4 mixture in nanoporous carbons: effects of edge-functionalization.

PubMed

Lu, Xiaoqing; Jin, Dongliang; Wei, Shuxian; Zhang, Mingmin; Zhu, Qing; Shi, Xiaofan; Deng, Zhigang; Guo, Wenyue; Shen, Wenzhong

2015-01-21

The effect of edge-functionalization on the competitive adsorption of a binary CO2-CH4 mixture in nanoporous carbons (NPCs) has been investigated for the first time by combining density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulation. Our results show that edge-functionalization has a more positive effect on the single-component adsorption of CO2 than CH4, therefore significantly enhancing the selectivity of CO2 over CH4, in the order of NH2-NPC > COOH-NPC > OH-NPC > H-NPC > NPC at low pressure. The enhanced adsorption originates essentially from the effects of (1) the conducive environment with a large pore size and an effective accessible surface area, (2) the high electronegativity/electropositivity, (3) the strong adsorption energy, and (4) the large electrostatic contribution, due to the inductive effect/direct interaction of the embedded edge-functionalized groups. The larger difference from these effects results in the higher competitive adsorption advantage of CO2 in the binary CO2-CH4 mixture. Temperature has a negative effect on the gas adsorption, but no obvious influence on the electrostatic contribution on selectivity. With the increase of pressure, the selectivity of CO2 over CH4 first decreases sharply and subsequently flattens out to a constant value. This work highlights the potential of edge-functionalized NPCs in competitive adsorption, capture, and separation for the binary CO2-CH4 mixture, and provides an effective and superior alternative strategy in the design and screening of adsorbent materials for carbon capture and storage.

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

NASA Astrophysics Data System (ADS)

DeFelice, Jeffrey

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

Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra

NASA Astrophysics Data System (ADS)

Lotfy, Hayam M.; Saleh, Sarah S.; Hassan, Nagiba Y.; Salem, Hesham

2015-02-01

This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt's method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

Molecular investigation on the binding of Cd(II) by the binary mixtures of montmorillonite with two bacterial species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Huihui; Qu, ChenChen; Liu, Jing

Bacteria and phyllosilicate commonly coexist in the natural environment, producing various bacteria–clay complexes that are capable of immobilizing heavy metals, such as cadmium, via adsorption. However, the molecular binding mechanisms of heavy metals on these complex aggregates still remain poorly understood. This study investigated Cd adsorption on Gram-positive B. subtilis, Gram-negative P. putida and their binary mixtures with montmorillonite (Mont) using the Cd K-edge x-ray absorption spectroscopy (XAS) and isothermal titration calorimetry (ITC). We observed a lower adsorptive capacity for P. putida than B. subtilis, whereas P. putida–Mont and B. subtilis–Mont mixtures showed nearly identical Cd adsorption behaviors. EXAFS fitsmore » and ITC measurements demonstrated more phosphoryl binding of Cd in P. putida. The decreased coordination of C atoms around Cd and the reduced adsorption enthalpies and entropies for the binary mixtures compared to that for individual bacteria suggested that the bidentate Cd-carboxyl complexes in pure bacteria systems were probably transformed into monodentate complexes that acted as ionic bridging structure between bacteria and motmorillonite. This study clarified the binding mechanism of Cd at the bacteria–phyllosilicate interfaces from a molecular and thermodynamic view, which has an environmental significance for predicting the chemical behavior of trace elements in complex mineral–organic systems.« less

Preferential solvation of Brooker's merocyanine in binary solvent mixtures composed of formamides and hydroxylic solvents.

PubMed

Bevilaqua, Tharly; da Silva, Domingas C; Machado, Vanderlei G

2004-03-01

The ET polarity values of 4-[(1-methyl-4(1H)-pyridinylidene)-ethylidene]-2,5-cyclohexadien-1-one (Brooker's merocyanine) were collected in mixed-solvent systems comprising a formamide [N,N-dimethylformamide (DMF), N-methylformamide (NMF) or formamide (FA)] and a hydroxylic (water, methanol, ethanol, propan-2-ol or butan-1-ol) solvent. Binary mixtures involving DMF and the other formamides (NMF and FA) as well as NMF and FA were also studied. These data were employed in the investigation of the preferential solvation (PS) of the probe. Each solvent system was analyzed in terms of both solute-solvent and solvent-solvent interactions. These latter interactions were responsible for the synergism observed in many binary mixtures. This synergistic behaviour was observed for DMF-propan-2-ol, DMF-butan-1-ol, FA-methanol, FA-ethanol and for the mixtures of the alcohols with NMF. All data were successfully fitted to a model based on solvent-exchange equilibria, which allowed the separation of the different contributions of the solvent species in the solvation shell of the dye. The results suggest that both hydrogen bonding and solvophobic interactions contribute to the formation of the solvent complexes responsible for the observed synergistic effects in the PS of the dye.

Investigation of Deviations from Ideality in the Two Liquid Phase Region of Systems of Medium Molecular Weight Hydrocarbon Mixtures and Water.

DTIC Science & Technology

1986-02-01

determined by refractometry using a Bausch and Lomb Refractometer (Abbe 3-L). Refractive index calibrations for the binary mixtures examined are given in...mixture sample was taken and analyzed by refractometry . b. Results The results of the vapor pressure experiments and the Redlich- Kister coefficients

Diffuse interface method for a compressible binary fluid.

PubMed

Liu, Jiewei; Amberg, Gustav; Do-Quang, Minh

2016-01-01

Multicomponent, multiphase, compressible flows are very important in real life, as well as in scientific research, while their modeling is in an early stage. In this paper, we propose a diffuse interface model for compressible binary mixtures, based on the balance of mass, momentum, energy, and the second law of thermodynamics. We show both analytically and numerically that this model is able to describe the phase equilibrium for a real binary mixture (CO_{2} + ethanol is considered in this paper) very well by adjusting the parameter which measures the attraction force between molecules of the two components in the model. We also show that the calculated surface tension of the CO_{2} + ethanol mixture at different concentrations match measurements in the literature when the mixing capillary coefficient is taken to be the geometric mean of the capillary coefficient of each component. Three different cases of two droplets in a shear flow, with the same or different concentration, are simulated, showing that the higher concentration of CO_{2} the smaller the surface tension and the easier the drop deforms.

Dynamics of glycerine and water transport across human skin from binary mixtures.

PubMed

Ventura, S A; Kasting, G B

2017-04-01

Skin transport properties of glycerine and water from binary mixtures contacting human skin were determined to better understand the mechanism of skin moisturization by aqueous glycerine formulations. Steady-state permeation for 3 H 2 O and 14 C-glycerine across split-thickness human skin in vitro and desorption dynamics of the same permeants in isolated human stratum corneum (HSC) were experimentally determined under near equilibrium conditions. These data were compared to a priori values developed in the context of a thermodynamic model for binary mixtures of glycerine and water and a previously determined water sorption isotherm for HSC. This allowed the estimation of diffusion and partition coefficients for each permeant in the HSC, as well as HSC thickness, as a function of composition of the contacting solution. These data may be used to estimate water retention and associated HSC swelling related to the absorption and slow release of glycerine from the skin. It took 6+ days for glycerine to completely desorb from HSC immersed in glycerine/water binary solutions. Desorption of both 3 H 2 O and 14 C-glycerine from HSC was slower in pure water than from binary mixtures, a result that is largely explained by the greater swelling of HSC in water. Parametric relationships were developed for water and glycerine intradiffusivities in HSC as functions of HSC water content, and a mutual diffusion coefficient was estimated by analogy with glycerine/water binary solutions. The intradiffusivity of 14 C-glycerine in HSC as inferred from sorption/desorption experiments was shown to be approximately 10-fold less than that inferred from permeation experiments, whereas the corresponding values for 3 H 2 O were comparable. These studies confirm that glycerine enters HSC in substantial quantities and has a long residence time therein. The coupling between bulk water and glycerine transport projected from binary solution data suggests the net effect of glycerine is to slow water loss from the skin. The data support the concept of glycerine as a humectant with an excellent balance of skin penetration and retention characteristics; however, they do not rule out the possibility of an additional biological effect on skin barrier homoeostasis. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Chiral Polymers.

DTIC Science & Technology

1984-10-01

regardless of the method of polymerization. The styrene-bead copolymers were packed in HPLC columns, but none were especiall, effective in separating...enantiomers in a racemic mixture. The chiral butyrolactone polymer was coated on silica, but this material did not effect resolution of racemic mixtures in an...been effected utilizing chiral oxazolines3 prompted the initial efforts to synthesize various chiral 2-vinyl- oxazoline monomers for incorporation

Treatment of mercury containing waste

DOEpatents

Kalb, Paul D.; Melamed, Dan; Patel, Bhavesh R; Fuhrmann, Mark

2002-01-01

A process is provided for the treatment of mercury containing waste in a single reaction vessel which includes a) stabilizing the waste with sulfur polymer cement under an inert atmosphere to form a resulting mixture and b) encapsulating the resulting mixture by heating the mixture to form a molten product and casting the molten product as a monolithic final waste form. Additional sulfur polymer cement can be added in the encapsulation step if needed, and a stabilizing additive can be added in the process to improve the leaching properties of the waste form.

Surface segregation in binary mixtures of imidazolium-based ionic liquids

NASA Astrophysics Data System (ADS)

Souda, Ryutaro

2010-09-01

Surface composition of binary mixtures of room-temperature ionic liquids has been investigated using time-of-flight secondary ion mass spectrometry at room temperature over a wide composition range. The imidazolium cations with longer aliphatic groups tend to segregate to the surface, and a bis(trifluoromethanesulfonyl)imide anion (Tf 2N -) is enriched at the surface relative to hexafluorophosphate (PF 6-). The surface of an equimolar mixture of Li[Tf 2N] and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6]) has a nominal composition of [bmim][Tf 2N] because of surface segregation and ligand exchange. The surface segregation of cations and anions is likely to result from alignment of specific ligand-exchanged molecules at the topmost surface layer to exclude more hydrophobic part of the molecules.

Phase-transition oscillations induced by a strongly focused laser beam

NASA Astrophysics Data System (ADS)

Devailly, Clémence; Crauste-Thibierge, Caroline; Petrosyan, Artyom; Ciliberto, Sergio

2015-11-01

We report the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture when this is enlightened by a strongly focused infrared laser beam. The mixture is poly-methyl-meth-acrylate (PMMA)-3-octanone, which has an upper critical solution temperature at Tc=306.6 K and volume fraction ϕc=12.8 % [Crauste et al., arXiv:1310.6720, 2013]. We describe the dynamical properties of the oscillations, which are produced by a competition between various effects: the local accumulation of PMMA produced by the laser beam, thermophoresis, and nonlinear diffusion. We show that the main properties of this kind of oscillations can be reproduced in the Landau theory for a binary mixture in which a local driving mechanism, simulating the laser beam, is introduced.

Study on Solution Properties of Binary Mixtures of Some Industrially Important Solvents with Cyclohexylamine and Cyclohexanone at 298.15 K

NASA Astrophysics Data System (ADS)

Roy, Mahendra Nath; Das, Rajesh Kumar; Chanda, Riju

2010-03-01

Densities and viscosities were measured for the binary mixtures of cyclohexylamine and cyclohexanone with butyl acetate, butanone, butylamine, tert-butylamine, and 2-butoxyethanol at 298.15 K over the entire composition range. From density data, the values of the excess molar volume ( V E) have been calculated. The experimental viscosity data were correlated by means of the equation of Grunberg-Nissan. The density and viscosity data have been analyzed in terms of some semiempirical viscosity models. The results are discussed in terms of molecular interactions and structural effects. The excess molar volume is found to be either negative or positive depending on the molecular interactions and the nature of the liquid mixtures and is discussed in terms of molecular interactions and structural changes.

Electrical properties of binary mixtures of amino silicone oil and methyl iso butyl ketone

NASA Astrophysics Data System (ADS)

Shah, K. N.; Rana, V. A.; Vankar, H. P.

2018-05-01

The real and imaginary parts of the dielectric function of the binary mixtures of the methyl iso butyl ketone and amino silicone oil in the frequency range 100 Hz to 2 MHz were measured using precision LCR meter at 305.15 K. The electrical properties such as electrical modulus M*(ω), electrical conductivity σ*(ω) and complex impedance Z*(ω) were calculated using the dielectric function ɛ*(ω). The ionic polarization relaxation time (Τσ) and D.C. conductivity (σdc) were also calculated using electrical properties. The ionic behavior of methyl iso butyl ketone and non-ionic behavior of amino silicone oil are also explained. The electrical parameters are used to gain information about the effect of concentration variation of components of the mixtures on the electrical properties.

The structures of the crystalline phase and columnar mesophase of rhodium (II) heptanoate and of its binary mixture with copper (II) heptanoate probed by EXAFS

NASA Astrophysics Data System (ADS)

Inb-Elhaj, M.; Guillon, D.; Skoulios, A.; Maldivi, P.; Giroud-Godquin, A. M.; Marchon, J.-C.

1992-12-01

EXAFS was used to investigate the local structure of the polar spines of rhodium (II) soaps in the columnar liquid crystalline state. It was also used to ascertain the degree of blending of the cores in binary mixtures of rhodium (II) and copper (II) soaps. For the pure rhodium soaps, the columns are shown to result from the stacking of binuclear metal-metal bonded dirhodium tetracarboxylate units bonded to one another by apical ligation of the metal atom of each complex with one of the oxygen atoms of the adjacent molecule. Mixtures of rhodium (II) and copper (II) soaps give a hexagonal columnar mesophase in which pure rhodium and pure copper columns are randomly distributed.

Process feasibility study in support of silicon material, task 1

NASA Technical Reports Server (NTRS)

Li, K. Y.; Hansen, K. C.; Yaws, C. L.

1979-01-01

Analyses of process system properties were continued for materials involved in the alternate processes under consideration for semiconductor silicon. Primary efforts centered on physical and thermodynamic property data for dichlorosilane. The following property data are reported for dichlorosilane which is involved in processing operations for solar cell grade silicon: critical temperature, critical pressure, critical volume, critical density, acentric factor, vapor pressure, heat of vaporization, gas heat capacity, liquid heat capacity and density. Work was initiated on the assembly of a system to prepare binary gas mixtures of known proportions and to measure the thermal conductivity of these mixtures between 30 and 350 C. The binary gas mixtures include silicon source material such as silanes and halogenated silanes which are used in the production of semiconductor silicon.

Coarse-grained modelling of triglyceride crystallisation: a molecular insight into tripalmitin tristearin binary mixtures by molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Pizzirusso, Antonio; Brasiello, Antonio; De Nicola, Antonio; Marangoni, Alejandro G.; Milano, Giuseppe

2015-12-01

The first simulation study of the crystallisation of a binary mixture of triglycerides using molecular dynamics simulations is reported. Coarse-grained models of tristearin (SSS) and tripalmitin (PPP) molecules have been considered. The models have been preliminarily tested in the crystallisation of pure SSS and PPP systems. Two different quenching procedures have been tested and their performances have been analysed. The structures obtained from the crystallisation procedures show a high orientation order and a high content of molecules in the tuning fork conformation, comparable with the crystalline α phase. The behaviour of melting temperatures for the α phase of the mixture SSS/PPP obtained from the simulations is in qualitative agreement with the behaviour that was experimentally determined.

Odourant dominance in olfactory mixture processing: what makes a strong odourant?

PubMed Central

Schubert, Marco; Sandoz, Jean-Christophe; Galizia, Giovanni; Giurfa, Martin

2015-01-01

The question of how animals process stimulus mixtures remains controversial as opposing views propose that mixtures are processed analytically, as the sum of their elements, or holistically, as unique entities different from their elements. Overshadowing is a widespread phenomenon that can help decide between these alternatives. In overshadowing, an individual trained with a binary mixture learns one element better at the expense of the other. Although element salience (learning success) has been suggested as a main explanation for overshadowing, the mechanisms underlying this phenomenon remain unclear. We studied olfactory overshadowing in honeybees to uncover the mechanisms underlying olfactory-mixture processing. We provide, to our knowledge, the most comprehensive dataset on overshadowing to date based on 90 experimental groups involving more than 2700 bees trained either with six odourants or with their resulting 15 binary mixtures. We found that bees process olfactory mixtures analytically and that salience alone cannot predict overshadowing. After normalizing learning success, we found that an unexpected feature, the generalization profile of an odourant, was determinant for overshadowing. Odourants that induced less generalization enhanced their distinctiveness and became dominant in the mixture. Our study thus uncovers features that determine odourant dominance within olfactory mixtures and allows the referring of this phenomenon to differences in neural activity both at the receptor and the central level in the insect nervous system. PMID:25652840

Long-time tails of the green-kubo integrands for a binary mixture

NASA Astrophysics Data System (ADS)

Wood, W. W.

1989-11-01

The long-time tails for the mutual diffusion coefficient, the thermal diffusivity, the thermal conductivity, and the shear and longitudinal viscosities (from which the tail of the bulk viscosity can be calculated) of a nonreactive binary mixture are calculated from mode-coupling theory, and compared with a prior calculation by Pomeau. Three different choices of the thermal forces and currents are considered, with the results found to take their simplest form in the case of the de Groot "double-primed set". The decompositions into the kinetic, potential, and cross terms are given.

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

PubMed

Hirota, Yuichiro; Maeda, Yohei; Yamamoto, Yusuke; Miyamoto, Manabu; Nishiyama, Norikazu

2017-08-03

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H₂/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H₂ (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

Solidification of a binary mixture

NASA Technical Reports Server (NTRS)

Antar, B. N.

1982-01-01

The time dependent concentration and temperature profiles of a finite layer of a binary mixture are investigated during solidification. The coupled time dependent Stefan problem is solved numerically using an implicit finite differencing algorithm with the method of lines. Specifically, the temporal operator is approximated via an implicit finite difference operator resulting in a coupled set of ordinary differential equations for the spatial distribution of the temperature and concentration for each time. Since the resulting differential equations set form a boundary value problem with matching conditions at an unknown spatial point, the method of invariant imbedding is used for its solution.

Superabsorbing gel for actinide, lanthanide, and fission product decontamination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaminski, Michael D.; Mertz, Carol J.

The present invention provides an aqueous gel composition for removing actinide ions, lanthanide ions, fission product ions, or a combination thereof from a porous surface contaminated therewith. The composition comprises a polymer mixture comprising a gel forming cross-linked polymer and a linear polymer. The linear polymer is present at a concentration that is less than the concentration of the cross-linked polymer. The polymer mixture is at least about 95% hydrated with an aqueous solution comprising about 0.1 to about 3 percent by weight (wt %) of a multi-dentate organic acid chelating agent, and about 0.02 to about 0.6 molar (M)more » carbonate salt, to form a gel. When applied to a porous surface contaminated with actinide ions, lanthanide ions, and/or other fission product ions, the aqueous gel absorbs contaminating ions from the surface.« less

Toxicity of binary mixtures of metal oxide nanoparticles to Nitrosomonas europaea.

PubMed

Yu, Ran; Wu, Junkang; Liu, Meiting; Zhu, Guangcan; Chen, Lianghui; Chang, Yan; Lu, Huijie

2016-06-01

Although the widely used metal oxide nanoparticles (NPs) titanium dioxide NPs (n-TiO2), cerium dioxide NPs (n-CeO2), and zinc oxide NPs (n-ZnO) have been well known for their potential cytotoxicities to environmental organisms, their combined effects have seldom been investigated. In this study, the short-term binary effect of n-CeO2 and n-TiO2 or n-ZnO on a model ammonia oxidizing bacterium, Nitrosomonas europaea were evaluated based on the examinations of cells' physiological, metabolic, and transcriptional responses. The addition of n-TiO2 mitigated the negative effect of more toxic n-CeO2 and the binary toxicity (antagonistic toxicity) of n-TiO2 and n-CeO2 was generally lower than the single NPs induced one. While the n-CeO2/n-ZnO mixture exerted higher cytotoxicity (synergistic cytotoxicity) than that from single NPs. The increased addition of the less toxic n-CeO2 exaggerated the binary toxicity of n-CeO2/n-ZnO mixture although the solubility of n-ZnO was not significantly affected, which excluded the contribution of the dissolved Zn ions to the enhancement of the combined cytotoxicity. The cell membrane disturbances and NP internalizations were detected for all the NP impacted cultures and the electrostatic interactions among the two distinct NPs and the cells were expected to play a key role in mediating their direct contacts and the eventual binary nanotoxicity to the cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anisotropic elasticity of quasi-one-component polymer nanocomposites.

PubMed

Voudouris, Panayiotis; Choi, Jihoon; Gomopoulos, Nikos; Sainidou, Rebecca; Dong, Hongchen; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Fytas, George

2011-07-26

The in-plane and out-of-plane elastic properties of thin films of "quasi-one-component" particle-brush-based nanocomposites are compared to those of "classical" binary particle-polymer nanocomposite systems with near identical overall composition using Brillouin light scattering. Whereas phonon propagation is found to be independent of the propagation direction for the binary particle/polymer blend systems, a pronounced splitting of the phonon propagation velocity along the in-plane and out-of-plane film direction is observed for particle-brush systems. The anisotropic elastic properties of quasi-one-component particle-brush systems are interpreted as a consequence of substrate-induced order formation into layer-type structures and the associated breaking of the symmetry of the film. The results highlight new opportunities to engineer quasi-one-component nanocomposites with advanced control of structural and physical property characteristics based on the assembly of particle-brush materials.

Organic–inorganic binary mixture matrix for comprehensive laser-desorption ionization mass spectrometric analysis and imaging of medium-size molecules including phospholipids, glycerolipids, and oligosaccharides

DOE PAGES

Feenstra, Adam D.; Ames Lab., Ames, IA; O'Neill, Kelly C.; ...

2016-10-13

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a widely adopted, versatile technique, especially in high-throughput analysis and imaging. However, matrix-dependent selectivity of analytes is often a severe limitation. In this work, a mixture of organic 2,5-dihydroxybenzoic acid and inorganic Fe 3O 4 nanoparticles is developed as a binary MALDI matrix to alleviate the well-known issue of triacylglycerol (TG) ion suppression by phosphatidylcholine (PC). In application to lipid standards and maize seed cross-sections, the binary matrix not only dramatically reduced the ion suppression of TG, but also efficiently desorbed and ionized a wide variety of lipids such as cationic PC, anionicmore » phosphatidylethanolamine (PE) and phosphatidylinositol (PI), and neutral digalactosyldiacylglycerol (DGDG). The binary matrix was also very efficient for large polysaccharides, which were not detected by either of the individual matrices. As a result, the usefulness of the binary matrix is demonstrated in MS imaging of maize seed sections, successfully visualizing diverse medium-size molecules and acquiring high-quality MS/MS spectra for these compounds.« less

Experimental evidence for excess entropy discontinuities in glass-forming solutions.

PubMed

Lienhard, Daniel M; Zobrist, Bernhard; Zuend, Andreas; Krieger, Ulrich K; Peter, Thomas

2012-02-21

Glass transition temperatures T(g) are investigated in aqueous binary and multi-component solutions consisting of citric acid, calcium nitrate (Ca(NO(3))(2)), malonic acid, raffinose, and ammonium bisulfate (NH(4)HSO(4)) using a differential scanning calorimeter. Based on measured glass transition temperatures of binary aqueous mixtures and fitted binary coefficients, the T(g) of multi-component systems can be predicted using mixing rules. However, the experimentally observed T(g) in multi-component solutions show considerable deviations from two theoretical approaches considered. The deviations from these predictions are explained in terms of the molar excess mixing entropy difference between the supercooled liquid and glassy state at T(g). The multi-component mixtures involve contributions to these excess mixing entropies that the mixing rules do not take into account. © 2012 American Institute of Physics

Configuration-specific kinetic theory applied to an ideal binary gas mixture.

PubMed

Wiseman, Floyd L

2006-10-05

This paper is the second in a two-part series dealing with the configuration-specific analyses for molecular collision events of hard, spherical molecules at thermal equilibrium. The first paper analyzed a single-component system, and the reader is referred to it for the fundamental concepts. In this paper, the expressions for the configuration-specific collision frequencies and the average line-of-centers collision angles and speeds are derived for an ideal binary gas mixture. The analyses show that the average line-of-centers quantities are all dependent upon the ratio of the masses of the two components, but not upon molecular size. Of course, the configuration-specific collision frequencies do depend on molecular size. The expression for the overall binary collision frequency is a simple sum of the configuration-specific collision frequencies and is identical to the conventional expression.

Effect of semiconductor polymer backbone structures and side-chain parameters on the facile separation of semiconducting single-walled carbon nanotubes from as-synthesized mixtures

NASA Astrophysics Data System (ADS)

Lee, Dennis T.; Chung, Jong Won; Park, Geonhee; Kim, Yun-Tae; Lee, Chang Young; Cho, Yeonchoo; Yoo, Pil J.; Han, Jae-Hee; Shin, Hyeon-Jin; Kim, Woo-Jae

2018-01-01

Semiconducting single-walled carbon nanotubes (SWNTs) show promise as core materials for next-generation solar cells and nanoelectronic devices. However, most commercial SWNT production methods generate mixtures of metallic SWNTs (m-SWNTs) and semiconducting SWNT (sc-SWNTs). Therefore, sc-SWNTs must be separated from their original mixtures before use. In this study, we investigated a polymer-based, noncovalent sc-SWNT separation approach, which is simple to perform and does not disrupt the electrical properties of the SWNTs, thus improving the performance of the corresponding sc-SWNT-based applications. By systematically investigating the effect that different structural features of the semiconductor polymer have on the separation of sc-SWNTs, we discovered that the length and configuration of the alkyl side chains and the rigidity of the backbone structure exert significant effects on the efficiency of sc-SWNT separation. We also found that electron transfer between the semiconductor polymers and sc-SWNTs is strongly affected by their energy-level alignment, which can be tailored by controlling the donor-acceptor configuration in the polymer backbone structures. Among the polymers investigated, the highly planar P8T2Z-C12 semiconductor polymer showed the best sc-SWNT separation efficiency and unprecedentedly strong electronic interaction with the sc-SWNTs, which is important for improving their performance in applications.

Mechanical and Permeability Characteristics of Latex-Modified Pre-Packed Pavement Repair Concrete as a Function of the Rapid-Set Binder Content

PubMed Central

Han, Jae-Woong; Jeon, Ji-Hong; Park, Chan-Gi

2015-01-01

We evaluated the strength and durability characteristics of latex-polymer-modified, pre-packed pavement repair concrete (LMPPRC) with a rapid-set binder. The rapid-set binder was a mixture of rapid-set cement and silica sand, where the fluidity was controlled using a latex polymer. The resulting mix exhibited a compressive strength of ≥21 MPa and a flexural strength of ≥3.5 MPa after 4 h of curing (i.e., the traffic opening term for emergency repairs of pavement). The ratio of latex polymer to rapid-set binder material was varied through 0.40, 0.33, 0.29, and 0.25. Mechanical characterization revealed that the mechanical performance, permeability, and impact resistance increased as the ratio of latex polymer to rapid-set binder decreased. The mixture exhibited a compressive strength of ≥21 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ≤0.29. The mixture exhibited a flexural strength of ≥3.5 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ≤0.33. The permeability resistance to chloride ions satisfied 2000 C after 7 days of curing for all ratios. The ratio of latex polymer to rapid-set binder material that satisfied all conditions for emergency pavement repair was ≤0.29. PMID:28793596

Mechanical and Permeability Characteristics of Latex-Modified Pre-Packed Pavement Repair Concrete as a Function of the Rapid-Set Binder Content.

PubMed

Han, Jae-Woong; Jeon, Ji-Hong; Park, Chan-Gi

2015-10-01

We evaluated the strength and durability characteristics of latex-polymer-modified, pre-packed pavement repair concrete (LMPPRC) with a rapid-set binder. The rapid-set binder was a mixture of rapid-set cement and silica sand, where the fluidity was controlled using a latex polymer. The resulting mix exhibited a compressive strength of ¥21 MPa and a flexural strength of ¥3.5 MPa after 4 h of curing (i.e., the traffic opening term for emergency repairs of pavement). The ratio of latex polymer to rapid-set binder material was varied through 0.40, 0.33, 0.29, and 0.25. Mechanical characterization revealed that the mechanical performance, permeability, and impact resistance increased as the ratio of latex polymer to rapid-set binder decreased. The mixture exhibited a compressive strength of ¥21 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ¤0.29. The mixture exhibited a flexural strength of ¥3.5 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ¤0.33. The permeability resistance to chloride ions satisfied 2000 C after 7 days of curing for all ratios. The ratio of latex polymer to rapid-set binder material that satisfied all conditions for emergency pavement repair was ¤0.29.

Low Mach number fluctuating hydrodynamics of multispecies liquid mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donev, Aleksandar, E-mail: donev@courant.nyu.edu; Bhattacharjee, Amit Kumar; Nonaka, Andy

We develop a low Mach number formulation of the hydrodynamic equations describing transport of mass and momentum in a multispecies mixture of incompressible miscible liquids at specified temperature and pressure, which generalizes our prior work on ideal mixtures of ideal gases [Balakrishnan et al., “Fluctuating hydrodynamics of multispecies nonreactive mixtures,” Phys. Rev. E 89 013017 (2014)] and binary liquid mixtures [Donev et al., “Low mach number fluctuating hydrodynamics of diffusively mixing fluids,” Commun. Appl. Math. Comput. Sci. 9(1), 47-105 (2014)]. In this formulation, we combine and extend a number of existing descriptions of multispecies transport available in the literature. Themore » formulation applies to non-ideal mixtures of arbitrary number of species, without the need to single out a “solvent” species, and includes contributions to the diffusive mass flux due to gradients of composition, temperature, and pressure. Momentum transport and advective mass transport are handled using a low Mach number approach that eliminates fast sound waves (pressure fluctuations) from the full compressible system of equations and leads to a quasi-incompressible formulation. Thermal fluctuations are included in our fluctuating hydrodynamics description following the principles of nonequilibrium thermodynamics. We extend the semi-implicit staggered-grid finite-volume numerical method developed in our prior work on binary liquid mixtures [Nonaka et al., “Low mach number fluctuating hydrodynamics of binary liquid mixtures,” http://arxiv.org/abs/1410.2300 (2015)] and use it to study the development of giant nonequilibrium concentration fluctuations in a ternary mixture subjected to a steady concentration gradient. We also numerically study the development of diffusion-driven gravitational instabilities in a ternary mixture and compare our numerical results to recent experimental measurements [Carballido-Landeira et al., “Mixed-mode instability of a miscible interface due to coupling between Rayleigh–Taylor and double-diffusive convective modes,” Phys. Fluids 25, 024107 (2013)] in a Hele-Shaw cell. We find that giant nonequilibrium fluctuations can trigger the instability but are eventually dominated by the deterministic growth of the unstable mode, in both quasi-two-dimensional (Hele-Shaw) and fully three-dimensional geometries used in typical shadowgraph experiments.« less

Cumulative Effects of In Utero Administration of Mixtures of Reproductive Toxicants that Disrupt Common Target Tissues via Diverse Mechanisms of Toxicity

PubMed Central

Rider, Cynthia V.; Furr, Johnathan R.; Wilson, Vickie S.; Gray, L. Earl

2010-01-01

Although risk assessments are typically conducted on a chemical-by-chemical basis, the 1996 Food Quality Protection Act required the US Environmental Protection Agency to consider cumulative risk of chemicals that act via a common mechanism of toxicity. To this end, we are conducting studies with mixtures of chemicals to elucidate mechanisms of joint action at the systemic level with the end goal of providing a framework for assessing the cumulative effects of reproductive toxicants. Previous mixture studies conducted with antiandrogenic chemicals are reviewed briefly and two new studies are described in detail. In all binary mixture studies, rats were dosed during pregnancy with chemicals, singly or in pairs at dosage levels equivalent to approximately one half of the ED50 for hypospadias or epididymal agenesis. The binary mixtures included: androgen receptor (AR) antagonists (vinclozolin plus procymidone), phthalate esters (DBP plus BBP and DEHP plus DBP), a phthalate ester plus an AR antagonist (DBP plus procymidone), a mixed mechanism androgen signaling disruptor (linuron) plus BBP, and two chemicals which disrupt epididymal differentiation through entirely different toxicity pathways: DBP (AR pathway) plus 2,3,7,8 TCDD (AhR pathway). We also conducted multi-component mixture studies combining several “antiandrogens” together. In the first study, seven chemicals (four pesticides and three phthalates) that elicit antiandrogenic effects at two different sites in the androgen signaling pathway (i.e. AR antagonist or inhibition of androgen synthesis) were combined. In the second study, three additional phthalates were added to make a ten chemical mixture. In both the binary mixture studies and the multi-component mixture studies, chemicals that targeted male reproductive tract development displayed cumulative effects that exceeded predictions based upon a response addition model and most often were in accordance with predictions based upon dose addition models. In summary, our results indicate that compounds that act by disparate mechanisms of toxicity to disrupt the dynamic interactions among the interconnected signaling pathways in differentiating tissues produce cumulative dose-additive effects, regardless of the mechanism or mode of action of the individual mixture component. PMID:20487044

COSMO-RS analysis on mixing properties obtained for the systems 1-butyl-X-methylpyridinium tetrafluoroborate [X = 2,3,4] and 1,ω-dibromoalkanes [ω = 1-6].

PubMed

Navas, Ana; Ortega, Juan; Palomar, José; Díaz, Carlos; Vreekamp, Remko

2011-05-07

A theoretical-experimental study for a set of 18 binary systems comprised of [bXmpy][BF(4)] (X=2-4) + 1,ω-Br(CH(2))(v)Br (v =ω=1-6) at a temperature of 298.15 K is presented. The solubility curves are determined for each binary system, establishing the intervals of measurement for the excess properties, H(E)(m) and V(E)(m). These properties are then determined for those systems that present a miscibility zone. Binary systems containing 1,ω-dibromoalkanes with ω=5,6 present reduced solubility intervals at the temperature of 298.15 K. However, the mixtures with 1,1-dibromomethane were totally miscible with the three isomers of 1-butyl-X-methylpyridinium tetrafluoroborate. Mixtures with dibromomethane present H(E)(m) <0, whereas H(E)(m) >0 for the other binary systems. Sigmoidal curves were observed for the V(E)(m) describing expansion and contraction processes for all the systems, except for the mixtures of [b2mpy][BF(4)] with the smaller dibromoalkanes, which present contraction effects. The COSMO-RS methodology was used to estimate the solubilities and the intermolecular interaction energies, giving an acceptable explanation of the behavioral structure of pure compounds and solutions. This journal is © the Owner Societies 2011

Benzoic Acid and Chlorobenzoic Acids: Thermodynamic Study of the Pure Compounds and Binary Mixtures With Water.

PubMed

Reschke, Thomas; Zherikova, Kseniya V; Verevkin, Sergey P; Held, Christoph

2016-03-01

Benzoic acid is a model compound for drug substances in pharmaceutical research. Process design requires information about thermodynamic phase behavior of benzoic acid and its mixtures with water and organic solvents. This work addresses phase equilibria that determine stability and solubility. In this work, Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was used to model the phase behavior of aqueous and organic solutions containing benzoic acid and chlorobenzoic acids. Absolute vapor pressures of benzoic acid and 2-, 3-, and 4-chlorobenzoic acid from literature and from our own measurements were used to determine pure-component PC-SAFT parameters. Two binary interaction parameters between water and/or benzoic acid were used to model vapor-liquid and liquid-liquid equilibria of water and/or benzoic acid between 280 and 413 K. The PC-SAFT parameters and 1 binary interaction parameter were used to model aqueous solubility of the chlorobenzoic acids. Additionally, solubility of benzoic acid in organic solvents was predicted without using binary parameters. All results showed that pure-component parameters for benzoic acid and for the chlorobenzoic acids allowed for satisfying modeling phase equilibria. The modeling approach established in this work is a further step to screen solubility and to predict the whole phase region of mixtures containing pharmaceuticals. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

High temperature concrete composites containing organosiloxane crosslinked copolymers

DOEpatents

Zeldin, A.; Carciello, N.; Kukacka, L.; Fontana, J.

High temperature polymer concrete composites comprising about 10 to 30% by weight of a liquid monomer mixture is described. It consists essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures thereof. About 70 to 90% by weight of an inert inorganic filler system containing silica sand and portland cement, Fe/sub 2/O/sub 3/, carbon black or mixtures thereof. Optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobyutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides are used to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

A nonlinear isobologram model with Box-Cox transformation to both sides for chemical mixtures.

PubMed

Chen, D G; Pounds, J G

1998-12-01

The linear logistical isobologram is a commonly used and powerful graphical and statistical tool for analyzing the combined effects of simple chemical mixtures. In this paper a nonlinear isobologram model is proposed to analyze the joint action of chemical mixtures for quantitative dose-response relationships. This nonlinear isobologram model incorporates two additional new parameters, Ymin and Ymax, to facilitate analysis of response data that are not constrained between 0 and 1, where parameters Ymin and Ymax represent the minimal and the maximal observed toxic response. This nonlinear isobologram model for binary mixtures can be expressed as [formula: see text] In addition, a Box-Cox transformation to both sides is introduced to improve the goodness of fit and to provide a more robust model for achieving homogeneity and normality of the residuals. Finally, a confidence band is proposed for selected isobols, e.g., the median effective dose, to facilitate graphical and statistical analysis of the isobologram. The versatility of this approach is demonstrated using published data describing the toxicity of the binary mixtures of citrinin and ochratoxin as well as a new experimental data from our laboratory for mixtures of mercury and cadmium.

A nonlinear isobologram model with Box-Cox transformation to both sides for chemical mixtures.

PubMed Central

Chen, D G; Pounds, J G

1998-01-01

The linear logistical isobologram is a commonly used and powerful graphical and statistical tool for analyzing the combined effects of simple chemical mixtures. In this paper a nonlinear isobologram model is proposed to analyze the joint action of chemical mixtures for quantitative dose-response relationships. This nonlinear isobologram model incorporates two additional new parameters, Ymin and Ymax, to facilitate analysis of response data that are not constrained between 0 and 1, where parameters Ymin and Ymax represent the minimal and the maximal observed toxic response. This nonlinear isobologram model for binary mixtures can be expressed as [formula: see text] In addition, a Box-Cox transformation to both sides is introduced to improve the goodness of fit and to provide a more robust model for achieving homogeneity and normality of the residuals. Finally, a confidence band is proposed for selected isobols, e.g., the median effective dose, to facilitate graphical and statistical analysis of the isobologram. The versatility of this approach is demonstrated using published data describing the toxicity of the binary mixtures of citrinin and ochratoxin as well as a new experimental data from our laboratory for mixtures of mercury and cadmium. PMID:9860894

The effect of vapor polarity and boiling point on breakthrough for binary mixtures on respirator carbon.

PubMed

Robbins, C A; Breysse, P N

1996-08-01

This research evaluated the effect of the polarity of a second vapor on the adsorption of a polar and a nonpolar vapor using the Wheeler model. To examine the effect of polarity, it was also necessary to observe the effect of component boiling point. The 1% breakthrough time (1% tb), kinetic adsorption capacity (W(e)), and rate constant (kv) of the Wheeler model were determined for vapor challenges on carbon beds for both p-xylene and pyrrole (referred to as test vapors) individually, and in equimolar binary mixtures with the polar and nonpolar vapors toluene, p-fluorotoluene, o-dichlorobenzene, and p-dichlorobenzene (referred to as probe vapors). Probe vapor polarity (0 to 2.5 Debye) did not systematically alter the 1% tb, W(e), or kv of the test vapors. The 1% tb and W(e) for test vapors in binary mixtures can be estimated reasonably well, using the Wheeler model, from single-vapor data (1% tb +/- 30%, W(e) +/- 20%). The test vapor 1% tb depended mainly on total vapor concentration in both single and binary systems. W(e) was proportional to test vapor fractional molar concentration (mole fraction) in mixtures. The kv for p-xylene was significantly different (p < or = 0.001) when compared according to probe boiling point; however, these differences were apparently of limited importance in estimating 1% tb for the range of boiling points tested (111 to 180 degrees C). Although the polarity and boiling point of chemicals in the range tested are not practically important in predicting 1% tb with the Wheeler model, an effect due to probe boiling point is suggested, and tests with chemicals of more widely ranging boiling point are warranted. Since the 1% tb, and thus, respirator service life, depends mainly on total vapor concentration, these data underscore the importance of taking into account the presence of other vapors when estimating respirator service life for a vapor in a mixture.

Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values.

PubMed

Rasouli, Zolaikha; Ghavami, Raouf

2016-08-05

Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD=0.12], 0.67-23.19 [LOD=0.13] and 0.73-25.12 [LOD=0.15] μgmL(-1) for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values

NASA Astrophysics Data System (ADS)

Rasouli, Zolaikha; Ghavami, Raouf

2016-08-01

Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD = 0.12], 0.67-23.19 [LOD = 0.13] and 0.73-25.12 [LOD = 0.15] μg mL- 1 for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples.

Original predictive approach to the compressibility of pharmaceutical powder mixtures based on the Kawakita equation.

PubMed

Mazel, Vincent; Busignies, Virginie; Duca, Stéphane; Leclerc, Bernard; Tchoreloff, Pierre

2011-05-30

In the pharmaceutical industry, tablets are obtained by the compaction of two or more components which have different physical properties and compaction behaviours. Therefore, it could be interesting to predict the physical properties of the mixture using the single-component results. In this paper, we have focused on the prediction of the compressibility of binary mixtures using the Kawakita model. Microcrystalline cellulose (MCC) and L-alanine were compacted alone and mixed at different weight fractions. The volume reduction, as a function of the compaction pressure, was acquired during the compaction process ("in-die") and after elastic recovery ("out-of-die"). For the pure components, the Kawakita model is well suited to the description of the volume reduction. For binary mixtures, an original approach for the prediction of the volume reduction without using the effective Kawakita parameters was proposed and tested. The good agreement between experimental and predicted data proved that this model was efficient to predict the volume reduction of MCC and L-alanine mixtures during compaction experiments. Copyright © 2011 Elsevier B.V. All rights reserved.

Solubility Limits in Lennard-Jones Mixtures: Effects of Disparate Molecule Geometries.

PubMed

Dyer, Kippi M; Perkyns, John S; Pettitt, B Montgomery

2015-07-23

In order to better understand general effects of the size and energy disparities between macromolecules and solvent molecules in solution, especially for macromolecular constructs self-assembled from smaller molecules, we use the first- and second-order exact bridge diagram extensions of the HNC integral equation theory to investigate single-component, binary, ternary, and quaternary mixtures of Lennard-Jones fluids. For pure fluids, we find that the HNCH3 bridge function integral equation (i.e., exact to third order in density) is necessary to quantitatively predict the pure gas and pure liquid sides of the coexistence region of the phase diagram of the Lennard-Jones fluid. For the mixtures, we find that the HNCH2 bridge function integral equation is sufficient to qualitatively predict solubility in the binary, ternary, and quaternary mixtures, up to the nominal solubility limit. The results, as limiting cases, should be useful to several problems, including accurate phase diagram predictions for complex mixtures, design of self-assembling nanostructures via solvent controls, and the solvent contributions to the conformational behavior of macromolecules in complex fluids.

SURFACTANT - POLYMER INTERACTION FOR IMPROVED OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unknown

1998-10-01

The goal of this research is to use the interaction between a surfactant and a polymer for efficient displacement of tertiary oil by improving slug integrity, adsorption and mobility control. Surfactant--polymer flooding has been shown to be highly effective in laboratory-scale linear floods. The focus of this proposal is to design an inexpensive surfactant-polymer mixture that can efficiently recover tertiary oil by avoiding surfactant slug degradation high adsorption and viscous/heterogeneity fingering. A mixture comprising a ''pseudo oil'' with appropriate surfactant and polymer has been selected to study micellar-polymer chemical flooding. The physical properties and phase behavior of this system havemore » been determined. A surfactant-polymer slug has been designed to achieve high efficiency recovery by improving phase behavior and mobility control. Recovery experiments have been performed on linear cores and a quarter 5-spot. The same recovery experiments have been simulated using a commercially available simulator (UTCHEM). Good agreement between experimental data and simulation results has been achieved.« less

Preparation And Evaluation Techniques of Porous Materials and Mixed Matrix Membranes for Targeted CO2 Separation Applications

NASA Astrophysics Data System (ADS)

Tessema, Tsemre Dingel Mesfin

The use of porous sorbents for physisorptive capture of CO2 from gas mixtures has been deemed attractive due to the low energy penalty associated with recycling of such materials. Porous organic polymers (POPs) have emerged as promising candidates with potential in the treatment of pre- and post- fuel combustion processes to separate CO2 from gas mixtures. Concurrently, significant advances have been made in establishing calculation methods that evaluate the practicality of porous sorbents for targeted gas separation applications. However, these methods rely on single gas adsorption isotherms without accounting for the dynamic gas mixtures encountered in real-life applications. To this end, the design and application of a dynamic gas mixture breakthrough apparatus to assess the CO2 separation performance of a new class of heteroatom (N and O) doped porous carbons derived from a Pyrazole precursor from flue gas mixtures is presented. Here in, two new benzimidazole linked polymers (BILPs) have been designed and synthesized. These polymers display high surface while their imidazole functionality and microporous nature resulted in high CO2 uptakes and isosteric heat of adsorption (Qst). BILP-30 displayed very good selectivity for CO2 in flue gas while BILP-31 was superior in CO2 separation from landfill gas mixtures at 298 K and 1 bar. Additionally, a new POP incorporating a highly conjugated pyrene core into a polymer framework linked by azo-bonds is presented. Azo-Py displays a nanofibrous morphology induced by the pi-pi stacking of the electron rich pyrene core. Due to its high surface area and microporous nature, Azo-Py displays impressive CO2 uptakes at 298 K and 1 bar. Evaluation of the S value for CO2 separation of Azo-Py revealed competitive values for flue gas and landfill gas at 298 K and 1 bar. Finally, a highly cross-linked benzimidazole linked polymer, BILP-4, was successfully incorporated into MatrimidRTM polymer to form a series of new mixed matrix membranes. The surface functionality of BILP-4 was exploited to enhance the interaction with MatrimidRTM polymer matrix to produce robust MMMs which displayed significantly improved CO2 gas permeabilities and ideal selectivities for CO 2/N2.

Highly Selective Ionic Block Copolymer Membranes

DTIC Science & Technology

2010-11-10

Multicomponent Diffusion and Sorption in an Ionic Polymer Membrane We recently measured the diffusion and sorption of methanol/water mixtures in Nafion (most...methanol feed concentration (17 M). Figure 1 shows one experiment where hydrated Nafion was exposed to a 2 M methanol/water liquid mixture resulting...copolymer membranes revealed several surprising results. Contrary to what has been observed in most ionic polymer membranes (e.g., Nafion ), the proton

Trophic transfer potential of two different crystalline phases of TiO2 NPs from Chlorella sp. to Ceriodaphnia dubia.

PubMed

Iswarya, V; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

2018-04-01

Owing to the increase in the usage of titanium dioxide nanoparticles (TiO 2 NPs), their release into the aquatic environment is inevitable. In the aquatic ecosystem, TiO 2 NPs can bio-magnify at various trophic levels in the food chain through dietary exposure. In the current study, the trophic transfer potential of two crystalline phases of TiO 2, anatase and rutile nanoparticles (individual as well as a binary mixture) has been evaluated in the lake water matrix using algae-daphnia system. Chlorella sp. and Ceriodaphnia dubia were used as test organisms to represent the algae-daphnia food chain of the freshwater ecosystem. Other than crystallinity, the effect of irradiation (visible and UV-A) was also investigated at the test concentrations, 75, 300, and 1200 μM. TiO 2 NPs treated algal diet produced significant mortality only at the test concentrations, 300 and 1200 μM. The type of irradiation and crystallinity doesn't have any impact on the mortality of daphnids through the dietary exposure of TiO 2 NPs. Comparing the mixture with individual NPs, binary mixture induced less mortality on C. dubia which signifies the antagonistic effect of NPs when they coexist. Statistical modeling confirmed the antagonistic effect of the binary mixture on C. dubia. As individual NPs, anatase and rutile forms showed a maximum Ti accumulation under UV-A and visible irradiation, respectively. BMF of TiO 2 NPs has been in validation with the bioaccumulation noted in C. dubia. Individual NPs (75 μM) showed higher BMF value of ∼23 under both UV-A (anatase) and visible (rutile) irradiation. Individual NPs showing higher BMF confirmed their trophic transfer potential in the aquatic food chain, primarily through the diet. In contrast, the binary mixture obtained a higher BMF of 1.9 and 0.79 at 75 and 300 μM under visible and UV-A irradiation, respectively. The plausible reason behind this decrement was the antagonistic effect of the mixture which significantly reduced their Ti bioaccumulation on C. dubia. Copyright © 2018 Elsevier B.V. All rights reserved.

A new strategy to engineer polymer bulk heterojunction solar cells with thick active layers via self-assembly of the tertiary columnar phase

DOE PAGES

Li, Hongfei; Yang, Zhenhua; Pan, Cheng; ...

2017-07-14

Here, we report that the addition of a non-photoactive tertiary polymer phase in the binary bulk heterojunction (BHJ) polymer solar cell leads to a self-assembled columnar nanostructure, enhancing the charge mobilities and photovoltaic efficiency with surprisingly increased optimal active blend thicknesses over 300 nm, 3–4 times larger than that of the binary counterpart. Using the prototypical poly(3-hexylthiophene) (P3HT):fullerene blend as a model BHJ system, we discover that the inert poly(methyl methacrylate) (PMMA) added in the binary BHJ blend self-assembles into vertical columns, which not only template the phase segregation of electron acceptor fullerenes but also induce the out-of-plane rotation ofmore » the edge-on-orientated crystalline P3HT phase. Using complementary interrogation methods including neutron reflectivity, X-ray scattering, atomic force microscopy, transmission electron microscopy, and molecular dynamics simulations, we show that the enhanced charge transport originates from the more randomized molecular stacking of the P3HT phase and the spontaneous segregation of fullerenes at the P3HT/PMMA interface, driven by the high surface tension between the two polymeric components. The results demonstrate a potential method for increasing the thicknesses of high-performance polymer BHJ solar cells with improved photovoltaic efficiency, alleviating the burden of stringently controlling the ultrathin blend thickness during the roll-to-roll-type large-area manufacturing environment.« less

Cyclodextrin based ternary system of modafinil: Effect of trimethyl chitosan and polyvinylpyrrolidone as complexing agents.

PubMed

Patel, Parth; Agrawal, Y K; Sarvaiya, Jayrajsinh

2016-03-01

Modafinil is an approved drug for the treatment of narcolepsy and have a strong market presence in many countries. The drug is widely consumed for off-label uses and currently listed as a restricted drug. Modafinil has very low water solubility. To enhance the aqueous solubility of modafinil by the formation of a ternary complex with Hydroxypropyl-β-cyclodextrin and two hydrophilic polymers was the main objective of the present study. Pyrrolidone (PVP K30) and a water soluble chitosan derivative, trimethyl chitosan (TMC) were studied by solution state and solid state characterization methods for their discriminatory efficiency in solubility enhancement of modafinil. Phase solubility study depicted the highest complexation efficiency (2.22) of cyclodextrin derivative in the presence of TMC compared to the same in the presence of PVP K30 (0.08) and in the absence of any polymer (0.92). FT-IR analysis of binary and ternary complex expressed comparable contribution of both polymers in formation of inclusion complex. The thermal behaviour of binary and ternary complex, involving individual polymers disclosed the influence of TMC on polymorphism of the drug. DSC study revealed efficiency of TMC to prevent conversion of metastable polymorphic form to stable polymorphic form. Ternary complex, involving TMC enhanced water solubility of the drug 1.5 times more compared to the binary complex of the drug whereas PVP K30 reduced the Solubility. Copyright © 2015 Elsevier B.V. All rights reserved.

Multiscale structure, interfacial cohesion, adsorbed layers, miscibility and properties in dense polymer-particle mixtures

NASA Astrophysics Data System (ADS)

Schweizer, Ken

2012-02-01

A major goal in polymer nanocomposite research is to understand and predict how the chemical and physical nature of individual polymers and nanoparticles, and thermodynamic state (temperature, composition, solvent dilution, filler loading), determine bulk assembly, miscibility and properties. Microscopic PRISM theory provides a route to this goal for equilibrium disordered mixtures. A major prediction is that by manipulating the net polymer-particle interfacial attraction, miscibility is realizable via the formation of thin thermodynamically stable adsorbed layers, which, however, are destroyed by entropic depletion and bridging attraction effects if interface cohesion is too weak or strong, respectively. This and related issues are quantitatively explored for miscible mixtures of hydrocarbon polymers, silica nanospheres, and solvent using x-ray scattering, neutron scattering and rheology. Under melt conditions, quantitative agreement between theory and silica scattering experiments is achieved under both steric stabilization and weak depletion conditions. Using contrast matching neutron scattering to characterize the collective structure factors of polymers, particles and their interface, the existence and size of adsorbed polymer layers, and their consequences on microstructure, is determined. Failure of the incompressible RPA, accuracy of PRISM theory, the nm thickness of adsorbed layers, and qualitative sensitivity of the bulk modulus to interfacial cohesion and particle size are demonstrated for concentrated PEO-silica-ethanol nanocomposites. Temperature-dependent complexity is discovered when water is the solvent, and nonequilibrium effects emerge for adsorbing entangled polymers that strongly impact structure. By varying polymer chemistry, the effect of polymer-particle attraction on the intrinsic viscosity is explored with striking non-classical effects observed. This work was performed in collaboration with S.Y.Kim, L.M.Hall, C.Zukoski and B.Anderson.

Synthesis and photoluminescence properties of novel Schiff base type polymer-rare earth complexes containing furfural-based bidentate Schiff base ligands

NASA Astrophysics Data System (ADS)

Gao, Baojiao; Zhang, Dandan; Li, Yanbin

2018-03-01

Luminescent polymer-rare earth complexes are an important class of photoluminescence and electroluminescence materials. Via molecular design, two furfural-based bidentate Schiff base ligands, furfural-aniline (FA) type ligand and furfural-cyclohexylamine (FC) type ligand, were bonded on the side chains of polysulfone (PSF), respectively, forming two functionalized macromolecules, PSF-FA and PSF-FC. And then through respective coordination reactions of the two functionalized macromolecules with Eu(Ⅲ) ion and Tb(Ⅲ) ion, novel luminescent binary and ternary (with 1,10-phenanthroline as the second ligand) polymer-rare earth complexes were synthesized. For these complexes, on basis of the characterization of their chemical structures, they photoluminescence properties were main researched, and the relationship between their luminescent properties and structures was explored. The experimental results show that the complexes coming from PSF-FA and Eu(Ⅲ) ion including binary and ternary complexes emit strong red luminescence, indicating that the bonded bidentate Schiff base ligand FA can sensitize the fluorescence emission of Eu(III) ion. While the complexes coming from PSF-FC and Tb(Ⅲ) ion produce green luminescence, displaying that the bonded bidentate Schiff base ligand FC can sensitize the fluorescence emission of Tb(Ⅲ) ion. The fluorescence emission intensities of the ternary complexes were stronger than that of binary complexes, reflecting the important effect of the second ligand. The fluorescence emission of the solid film of complexes is much stronger than that of the solutions of complexes. Besides, by comparison, it is found that the furfural (as a heteroaromatic compound)-based Schiff base type polymer-rare earth complexes have stronger fluorescence emission and higher energy transfer efficiency than salicylaldehyde (as a common aromatic compound)-based Schiff base type polymer-rare earth complexes.

Polymer Crowding in Confined Polymer-Nanoparticle Mixtures

NASA Astrophysics Data System (ADS)

Davis, Wyatt J.; Denton, Alan R.

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

Structural Elucidation of Poloxamer 237 and Poloxamer 237/Praziquantel Solid Dispersions: Impact of Poly(Vinylpyrrolidone) over Drug Recrystallization and Dissolution.

PubMed

Orlandi, Silvina; Priotti, Josefina; Diogo, Hermínio P; Leonardi, Dario; Salomon, Claudio J; Nunes, Teresa G

2018-04-01

Praziquantel (PZQ) is the recommended, effective, and safe treatment against all forms of schistosomiasis. Solid dispersions (SDs) in water-soluble polymers have been reported to increase solubility and bioavailability of poorly water-soluble drugs like PZQ, generally due to the amorphous form stabilization. In this work, poloxamer (PLX) 237 and poly(vinylpyrrolidone) (PVP) K30 were evaluated as potential carriers to revert PZQ crystallization. Binary and ternary SDs were prepared by the solvent evaporation method. PZQ solubility increased similarly with PLX either as binary physical mixtures or SDs. Such unpredicted data correlated well with crystalline PZQ and PLX as detected by solid-state NMR (ssNMR) and differential scanning calorimetry in those samples. Ternary PVP/PLX/PZQ SDs showed both ssNMR broad and narrow superimposed signals, thus revealing the presence of amorphous and crystalline PZQ, respectively, and exhibited the highest PZQ dissolution efficiency (up to 82% at 180 min). SDs with PVP provided a promising way to enhance solubility and dissolution rate of PZQ since PLX alone did not prevent recrystallization of amorphous PZQ. Based on ssNMR data, novel evidences on PLX structure and molecular dynamics were also obtained. As shown for the first time using ssNMR, propylene glycol and ethylene glycol constitute the PLX amorphous and crystalline components, respectively.

Molecular dynamics simulation for the test of calibrated OPLS-AA force field for binary liquid mixture of tri-iso-amyl phosphate and n-dodecane.

PubMed

Das, Arya; Ali, Sk Musharaf

2018-02-21

Tri-isoamyl phosphate (TiAP) has been proposed to be an alternative for tri-butyl phosphate (TBP) in the Plutonium Uranium Extraction (PUREX) process. Recently, we have successfully calibrated and tested all-atom optimized potentials for liquid simulations using Mulliken partial charges for pure TiAP, TBP, and dodecane by performing molecular dynamics (MD) simulation. It is of immense importance to extend this potential for the various molecular properties of TiAP and TiAP/n-dodecane binary mixtures using MD simulation. Earlier, efforts were devoted to find out a suitable force field which can explain both structural and dynamical properties by empirical parameterization. Therefore, the present MD study reports the structural, dynamical, and thermodynamical properties with different mole fractions of TiAP-dodecane mixtures at the entire range of mole fraction of 0-1 employing our calibrated Mulliken embedded optimized potentials for liquid simulation (OPLS) force field. The calculated electric dipole moment of TiAP was seen to be almost unaffected by the TiAP concentration in the dodecane diluent. The calculated liquid densities of the TiAP-dodecane mixture are in good agreement with the experimental data. The mixture densities at different temperatures are also studied which was found to be reduced with temperature as expected. The plot of diffusivities for TiAP and dodecane against mole fraction in the binary mixture intersects at a composition in the range of 25%-30% of TiAP in dodecane, which is very much closer to the TBP/n-dodecane composition used in the PUREX process. The excess volume of mixing was found to be positive for the entire range of mole fraction and the excess enthalpy of mixing was shown to be endothermic for the TBP/n-dodecane mixture as well as TiAP/n-dodecane mixture as reported experimentally. The spatial pair correlation functions are evaluated between TiAP-TiAP and TiAP-dodecane molecules. Further, shear viscosity has been computed by performing the non-equilibrium molecular dynamics employing the periodic perturbation method. The calculated shear viscosity of the binary mixture is found to be in excellent agreement with the experimental values. The use of the newly calibrated OPLS force field embedding Mulliken charges is shown to be equally reliable in predicting the structural and dynamical properties for the mixture without incorporating any arbitrary scaling in the force field or Lennard-Jones parameters. Further, the present MD simulation results demonstrate that the Stokes-Einstein relation breaks down at the molecular level. The present methodology might be adopted to evaluate the liquid state properties of an aqueous-organic biphasic system, which is of great significance in the interfacial science and technology.

Molecular dynamics simulation for the test of calibrated OPLS-AA force field for binary liquid mixture of tri-iso-amyl phosphate and n-dodecane

NASA Astrophysics Data System (ADS)

Das, Arya; Ali, Sk. Musharaf

2018-02-01

Tri-isoamyl phosphate (TiAP) has been proposed to be an alternative for tri-butyl phosphate (TBP) in the Plutonium Uranium Extraction (PUREX) process. Recently, we have successfully calibrated and tested all-atom optimized potentials for liquid simulations using Mulliken partial charges for pure TiAP, TBP, and dodecane by performing molecular dynamics (MD) simulation. It is of immense importance to extend this potential for the various molecular properties of TiAP and TiAP/n-dodecane binary mixtures using MD simulation. Earlier, efforts were devoted to find out a suitable force field which can explain both structural and dynamical properties by empirical parameterization. Therefore, the present MD study reports the structural, dynamical, and thermodynamical properties with different mole fractions of TiAP-dodecane mixtures at the entire range of mole fraction of 0-1 employing our calibrated Mulliken embedded optimized potentials for liquid simulation (OPLS) force field. The calculated electric dipole moment of TiAP was seen to be almost unaffected by the TiAP concentration in the dodecane diluent. The calculated liquid densities of the TiAP-dodecane mixture are in good agreement with the experimental data. The mixture densities at different temperatures are also studied which was found to be reduced with temperature as expected. The plot of diffusivities for TiAP and dodecane against mole fraction in the binary mixture intersects at a composition in the range of 25%-30% of TiAP in dodecane, which is very much closer to the TBP/n-dodecane composition used in the PUREX process. The excess volume of mixing was found to be positive for the entire range of mole fraction and the excess enthalpy of mixing was shown to be endothermic for the TBP/n-dodecane mixture as well as TiAP/n-dodecane mixture as reported experimentally. The spatial pair correlation functions are evaluated between TiAP-TiAP and TiAP-dodecane molecules. Further, shear viscosity has been computed by performing the non-equilibrium molecular dynamics employing the periodic perturbation method. The calculated shear viscosity of the binary mixture is found to be in excellent agreement with the experimental values. The use of the newly calibrated OPLS force field embedding Mulliken charges is shown to be equally reliable in predicting the structural and dynamical properties for the mixture without incorporating any arbitrary scaling in the force field or Lennard-Jones parameters. Further, the present MD simulation results demonstrate that the Stokes-Einstein relation breaks down at the molecular level. The present methodology might be adopted to evaluate the liquid state properties of an aqueous-organic biphasic system, which is of great significance in the interfacial science and technology.

Proteomic analysis of a model fish species exposed to individual pesticides and a binary mixture

EPA Science Inventory

Aquatic organisms are often exposed to multiple pesticides simultaneously. Due to the relatively poor characterization of mixture constituent interactions and the potential for highly complex exposure scenarios, there is considerable uncertainty in understanding the toxicity of m...

Boiling Temperature vs. Composition. An Almost-Exact Explicit Equation for a Binary Mixture Following Raoult's Law.

ERIC Educational Resources Information Center

Cardinali, Mario Emilio; Giomini, Claudio

1989-01-01

Proposes a simple procedure based on an expansion of the exponential terms of Raoult's law by applying it to the case of the benzene-toluene mixture. The results with experimental values are presented as a table. (YP)

Morphology and transport in biodegradable polymer compositions based on poly(3-hydroxybutyrate) and polyamide 54C

NASA Astrophysics Data System (ADS)

Zhul'Kina, A. L.; Ivantsova, E. L.; Filatova, A. G.; Kosenko, R. Yu.; Gumargalieva, K. Z.; Iordanskii, A. L.

2009-05-01

Complex investigation of the equilibrium sorption of water, diffusive transport of antiseptic, and morphology of mixed compositions based on polyoxybutirate and polyamide resin 54C has been performed to develop and analyze new biodegradable polymer compositions for controlled release of medicinal substances. Samples of mixtures were prepared by two methods: pressing under pressure and solvent evaporation from a polymer solution. The samples were compared and their morphology was analyzed by scanning electron microscopy. It is shown that the component ratio in the obtained mixtures affects their morphological, transport, and sorption characteristics.

Morphology and transport in biodegradable polymer compositions based on poly(3-hydroxybutyrate) and polyamide 54C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhul'kina, A. L.; Ivantsova, E. L.; Filatova, A. G.

2009-05-15

Complex investigation of the equilibrium sorption of water, diffusive transport of antiseptic, and morphology of mixed compositions based on polyoxybutirate and polyamide resin 54C has been performed to develop and analyze new biodegradable polymer compositions for controlled release of medicinal substances. Samples of mixtures were prepared by two methods: pressing under pressure and solvent evaporation from a polymer solution. The samples were compared and their morphology was analyzed by scanning electron microscopy. It is shown that the component ratio in the obtained mixtures affects their morphological, transport, and sorption characteristics.

Separation of non-racemic mixtures of enantiomers: an essential part of optical resolution.

PubMed

Faigl, Ferenc; Fogassy, Elemér; Nógrádi, Mihály; Pálovics, Emese; Schindler, József

2010-03-07

Non-racemic enantiomeric mixtures form homochiral and heterochiral aggregates in melt or suspension, during adsorption or recrystallization, and these diastereomeric associations determine the distribution of the enantiomers between the solid and other (liquid or vapour) phases. That distribution depends on the stability order of the homo- and heterochiral aggregates (conglomerate or racemate formation). Therefore, there is a correlation between the binary melting point phase diagrams and the experimental ee(I)vs. ee(0) curves (ee(I) refers to the crystallized enantiomeric mixtures, ee(0) is the composition of the starting ones). Accordingly, distribution of the enantiomeric mixtures between two phases is characteristic and usually significant enrichment can be achieved. There are two exceptions: no enrichment could be observed under thermodynamically controlled conditions when the starting enantiomer composition corresponded to the eutectic composition, or when the method used was unsuitable for separation. In several cases, when kinetic control governed the crystallization, the character of the ee(0)-ee(I) curve did not correlate with the melting point binary phase diagram.

Can an ammonium-based room temperature ionic liquid counteract the urea-induced denaturation of a small peptide?

PubMed

Ghosh, Soumadwip; Dey, Souvik; Patel, Mahendra; Chakrabarti, Rajarshi

2017-03-15

The folding/unfolding equilibrium of proteins in aqueous medium can be altered by adding small organic molecules generally termed as co-solvents. Denaturants such as urea are instrumental in the unfolding of proteins while protecting osmolytes favour the folded ensemble. Recently, room temperature ionic liquids (ILs) have been shown to counteract the deleterious effect of urea on proteins. In this paper, using atomistic molecular dynamics we show that a ternary mixture containing a particular ammonium-based IL, triethylammonium acetate (TEAA), and urea (in 1 : 5 molar ratio) helps a small 15-residue S-peptide analogue regain most of its native structure, whereas a binary aqueous mixture containing a large amount of urea alone completely distorts it. Our simulations show that the denaturant urea directly interacts with the peptide backbone in the binary mixture while for the ternary mixture both urea as well as the IL are preferentially excluded from the peptide surface.

Electro-olfactogram and multiunit olfactory receptor responses to binary and trinary mixtures of amino acids in the channel catfish, Ictalurus punctatus

PubMed Central

1989-01-01

In vivo electrophysiological recordings from populations of olfactory receptor neurons in the channel catfish, Ictalurus punctatus, clearly showed that responses to binary and trinary mixtures of amino acids were predictable with knowledge obtained from previous cross-adaptation studies of the relative independence of the respective binding sites of the component stimuli. All component stimuli, from which equal aliquots were drawn to form the mixtures, were adjusted in concentration to provide for approximately equal response magnitudes. The magnitude of the response to a mixture whose component amino acids showed significant cross-reactivity was equivalent to the response to any single component used to form that mixture. A mixture whose component amino acids showed minimal cross-adaptation produced a significantly larger relative response than a mixture whose components exhibited considerable cross-reactivity. This larger response approached the sum of the responses to the individual component amino acids tested at the resulting concentrations in the mixture, even though olfactory receptor dose-response functions for amino acids in this species are characterized by extreme sensory compression (i.e., successive concentration increments produce progressively smaller physiological responses). Thus, the present study indicates that the response to sensory stimulation of olfactory receptor sites is more enhanced by the activation of different receptor site types than by stimulus interaction at a single site type. PMID:2703818

Breakdown and Limit of Continuum Diffusion Velocity for Binary Gas Mixtures from Direct Simulation

NASA Astrophysics Data System (ADS)

Martin, Robert Scott; Najmabadi, Farrokh

2011-05-01

This work investigates the breakdown of the continuum relations for diffusion velocity in inert binary gas mixtures. Values of the relative diffusion velocities for components of a gas mixture may be calculated using of Chapman-Enskog theory and occur not only due to concentration gradients, but also pressure and temperature gradients in the flow as described by Hirschfelder. Because Chapman-Enskog theory employs a linear perturbation around equilibrium, it is expected to break down when the velocity distribution deviates significantly from equilibrium. This breakdown of the overall flow has long been an area of interest in rarefied gas dynamics. By comparing the continuum values to results from Bird's DS2V Monte Carlo code, we propose a new limit on the continuum approach specific to binary gases. To remove the confounding influence of an inconsistent molecular model, we also present the application of the variable hard sphere (VSS) model used in DS2V to the continuum diffusion velocity calculation. Fitting sample asymptotic curves to the breakdown, a limit, Vmax, that is a fraction of an analytically derived limit resulting from the kinetic temperature of the mixture is proposed. With an expected deviation of only 2% between the physical values and continuum calculations within ±Vmax/4, we suggest this as a conservative estimate on the range of applicability for the continuum theory.

Condensation of binary mixtures on horizontal tubes

NASA Astrophysics Data System (ADS)

Büchner, A.; Reif, A.; Rehfeldt, S.; Klein, H.

2017-12-01

The two most common models to describe the condensation of binary mixtures are the equilibrium model by Silver (Trans Inst Chem Eng 25:30-42, 1947) and the film model by Colburn and Drew (Transactions of the American Institute of Chemical Engineers 33:197-215, 1937), which is stated by Webb et al. (Int J Heat Mass Transf 39:3147-3156, 1996) as more accurate. The film model describes the outer heat transfer coefficient by subdividing it into two separate resistances against the heat transfer. The resistance of the liquid condensate film on the tube can be calculated with equations for the condensation of pure substances for the analogous flow pattern and geometry using the property data of the mixture. The resistance in the gas phase can be described by a thermodynamic parameter Z and the single phase heat transfer coefficient α G . In this work measurements for condensation of the binary mixtures n-pentane/iso-octane and iso-propanol/water on horizontal tubes for free convection are carried out. The obtained results are compared with the film model by Colburn and Drew (Transactions of the American Institute of Chemical Engineers 33:197-215, 1937). The comparison shows a rather big deviation between the theoretical model and the experimental results. To improve the prediction quality an own model based on dimensionless numbers is proposed, which describes the experimental results of this work significantly better than the film model.

Thermodiffusion Coefficient Analysis of n-Dodecane /n-Hexane Mixture at Different Mass Fractions and Pressure Conditions

NASA Astrophysics Data System (ADS)

Lizarraga, Ion; Bou-Ali, M. Mounir; Santamaría, C.

2018-03-01

In this study, the thermodiffusion coefficient of n-dodecane/n-hexane binary mixture at 25 ∘C mean temperature was determined for several pressure conditions and mass fractions. The experimental technique used to determine the thermodiffusion coefficient was the thermograviational column of cylindrical configuration. In turn, thermophysical properties, such as density, thermal expansion, mass expansion and dynamic viscosity up to 10 MPa were also determined. The results obtained in this work showed a linear relation between the thermophysical properties and the pressure. Thermodiffusion coefficient values confirm a linear effect when the pressure increases. Additionally, a new correlation based on the thermodiffusion coefficient for n C12/n C6 binary mixture at 25 ∘C temperature for any mass fraction and pressures, which reproduces the data within the experimental error, was proposed.

Method for molding ceramic powders

DOEpatents

Janney, Mark A.

1990-01-01

A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

Method for molding ceramic powders

DOEpatents

Janney, M.A.

1990-01-16

A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, where after the product may be sintered.

Development and characterization of adjustable refractive index scattering epoxy acrylate polymer layers

NASA Astrophysics Data System (ADS)

Eiselt, Thomas; Preinfalk, Jan; Gleißner, Uwe; Lemmer, Uli; Hanemann, Thomas

2017-03-01

Several polymer films for improved optical properties in optoelectronic devices are presented. In such optical applications, it is sometimes important to have a film with an adjusted refractive index, scattering properties, and a low surface roughness. These diffusing films can be used to increase the efficiency of optoelectronic components, such as organic light-emitting diodes. Three different epoxy acrylate mixtures containing Syntholux 291 EA, bisphenol A glycerolate dimethacrylate, and Sartomer SR 348 L are characterized and optimized with different additives. The adjustable refractive index of the material is achieved by chemical doping using 9-vinylcarbazole. Titanium nanoparticles in the mixtures generate light scattering and increase the refractive index additionally. A high-power stirrer is used to mix and disperse all chemical substances together to a homogenous mixture. The viscosity behavior of the mixtures is an important property for the selection of the production method and, therefore, the viscosity measurement results are presented. After the mixing, the monomer mixture is applied on glass substrates by screen printing. To initiate polymerization, the produced films are irradiated for 10 min with ultraviolet radiation and heat. Transmission measurements of the polymer matrix and roughness measurements complement the characterization.

Phase equilibrium measurements on twelve binary mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giles, N.F.; Wilson, H.L.; Wilding, W.V.

1996-11-01

Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin; methanol + hydrogen cyanide. For these systems, equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson, NRTL, or Redlich-Kister activity coefficient model tomore » represent the liquid phase. The infinite dilution activity coefficient of methylamine in N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone-rich half of the binary. Liquid-liquid equilibrium studies were made on the triethylene glycol + 1-pentene system at two temperatures by directly analyzing samples taken from each liquid phase.« less

High-Performance Polymers Having Low Melt Viscosities

NASA Technical Reports Server (NTRS)

Jensen, Brian J.

2005-01-01

High-performance polymers that have improved processing characteristics, and a method of making them, have been invented. One of the improved characteristics is low (relative to corresponding prior polymers) melt viscosities at given temperatures. This characteristic makes it possible to utilize such processes as resin-transfer molding and resin-film infusion and to perform autoclave processing at lower temperatures and/or pressures. Another improved characteristic is larger processing windows that is, longer times at low viscosities. Other improved characteristics include increased solubility of uncured polymer precursors that contain reactive groups, greater densities of cross-links in cured polymers, improved mechanical properties of the cured polymers, and greater resistance of the cured polymers to chemical attack. The invention is particularly applicable to poly(arylene ether)s [PAEs] and polyimides [PIs] that are useful as adhesives, matrices of composite materials, moldings, films, and coatings. PAEs and PIs synthesized according to the invention comprise mixtures of branched, linear, and star-shaped molecules. The monomers of these polymers can be capped with either reactive end groups to obtain thermosets or nonreactive end groups to obtain thermoplastics. The synthesis of a polymeric mixture according to the invention involves the use of a small amount of a trifunctional monomer. In the case of a PAE, the trifunctional monomer is a trihydroxy- containing compound for example, 1,3,5-trihydroxybenzene (THB). In the case of a PI, the trifunctional monomer is a triamine for example, triamino pyrimidine or melamine. In addition to the aforementioned trifunctional monomer, one uses the difunctional monomers of the conventional formulation of the polymer in question (see figure). In cases of nonreactive end caps, the polymeric mixtures of the invention have melt viscosities and melting temperatures lower than those of the corresponding linear polymers of equal molecular weights. The lower melting temperatures and melt viscosities provide larger processing windows. In cases of reactive end caps, the polymeric mixtures of the invention have lower melt viscosities before curing and the higher cross-link densities after curing (where branching in the uncured systems would become cross-links in the cured systems), relative to the corresponding linear polymers of equal molecular weights. The greater cross-link densities afford increased resistance to chemical attack and improved mechanical properties.

Refractive index and solubility control of para-cymene solutions for index-matched fluid-structure interaction studies

NASA Astrophysics Data System (ADS)

Fort, Charles; Fu, Christopher D.; Weichselbaum, Noah A.; Bardet, Philippe M.

2015-12-01

To deploy optical diagnostics such as particle image velocimetry or planar laser-induced fluorescence (PLIF) in complex geometries, it is beneficial to use index-matched facilities. A binary mixture of para-cymene and cinnamaldehyde provides a viable option for matching the refractive index of acrylic, a common material for scaled models and test sections. This fluid is particularly appropriate for large-scale facilities and when a low-density and low-viscosity fluid is sought, such as in fluid-structure interaction studies. This binary solution has relatively low kinematic viscosity and density; its use enables the experimentalist to select operating temperature and to increase fluorescence signal in PLIF experiments. Measurements of spectral and temperature dependence of refractive index, density, and kinematic viscosity are reported. The effect of the binary mixture on solubility control of Rhodamine 6G is also characterized.

Characterization of interfaces in Binary and Ternary Polymer Blends by Positron Lifetime Spectroscopy

NASA Astrophysics Data System (ADS)

Ranganathaiah, C.

2015-06-01

A miscible blend is a single-phase system with compact packing of the polymeric chains/segments due configuration/conformational changes upon blending. Differential Scanning Calorimetry (DSC) is the most employed method to ascertain whether the blend is miscible or immiscible. Positron Lifetime Spectroscopy (PLS) has been employed in recent times to study miscibility properties of polymer blends by monitoring the ortho-Positronium annihilation lifetimes as function of composition. However, just free volume monitoring and the DSC methods fail to provide the composition dependent miscibility of blends. To overcome this limitation, an alternative approach based on hydrodynamic interactions has been developed to derive this information using the same o-Ps lifetime measurements. This has led to the development of a new method of measuring composition dependent miscibility level in binary and ternary polymer blends. Further, the new method also provides interface characteristics for immiscible blends. The interactions between the blend components has a direct bearing on the strength of adhesion at the interface and hence the hydrodynamic interaction. Understanding the characteristic of interfaces which decides the miscibility level of the blend and their end applications is made easy by the present method. The efficacy of the present method is demonstrated for few binary and ternary blends.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helfferich, Julian; Lyubimov, Ivan; Reid, Daniel

Glasses produced via physical vapor deposition can display greater kinetic stability and lower enthalpy than glasses prepared by liquid cooling. While the reduced enthalpy has often been used as a measure of the stability, it is not obvious whether dynamic measures of stability provide the same view. Here, we study dynamics in vapor-deposited and liquid-cooled glass films using molecular simulations of a bead-spring polymer model as well as a Lennard-Jones binary mixture in two and three dimensions. We confirm that the dynamics in vapor-deposited glasses is indeed slower than in ordinary glasses. We further show that the inherent structure energymore » is a good reporter of local dynamics, and that aged systems and glasses prepared by cooling at progressively slower rates exhibit the same behavior as vapor-deposited materials when they both have the same inherent structure energy. These findings suggest that the stability inferred from measurements of the energy is also manifested in dynamic observables, and they strengthen the view that vapor deposition processes provide an effective strategy for creation of stable glasses.« less

Physics of Colloids in Space-2 (PCS-2)

NASA Technical Reports Server (NTRS)

Sankaran, Subramanian; Gasser, Urs; Manley, Suliana; Valentine, Megan; Prasad, Vikram; Rudhardt, Daniel; Bailey, Arthur; Dinsmore, Anthony; Segre, Phil; Doherty, Michael P.

2001-01-01

The Physics of Colloids-2 (PCS-2) experiment is aimed at investigating the basic physical properties of several types of colloidal suspensions. The three broad classes of colloidal systems of interest are binary colloids, colloid-polymer mixtures, and fractal gels. The objective is to understand their phase behavior as well as the kinetics of the phase transitions in the absence of gravity. The nucleation, growth, and morphology characteristics of the crystals and gels that form would be studied using confocal microscopy. These will be observed directly with excellent time resolution, and therefore extensive information about the different phases and their growth mechanisms will be gained. With the laser tweezers, it will be possible to measure the strength of these structures and to modify them in a controlled way, and the spectrophotometer will provide the possibility to probe their optical properties. We believe that this experiment will provide the basis for future 'colloid engineering' in which complicated structures with novel properties (e.g., photonic crystals) will be grown by controlled self-assembly.

Utilisation of the isobole methodology to study dietary peptide-drug and peptide-peptide interactive effects on dipeptidyl peptidase IV (DPP-IV) inhibition.

PubMed

Nongonierma, Alice B; FitzGerald, Richard J

2015-01-01

Inhibition of dipeptidyl peptidase-IV (DPP-IV) is used as a means to regulate post-prandial serum glucose in type 2 diabetics. The effect of drug (Sitagliptin®)/peptide and binary peptide mixtures on DPP-IV inhibition was studied using an isobole approach. Five peptides (Ile-Pro-Ile-Gln-Tyr, Trp-Lys, Trp-Pro, Trp-Arg and Trp-Leu), having DPP-IV half maximum inhibitory concentration values (IC₅₀)<60 μM and reported to act through different inhibition mechanisms, were investigated. The dose response relationship of Sitagliptin : peptide (1:0, 0:1, 1:852, 1:426 and 1:1704 on a molar basis) and binary Ile-Pro-Ile-Gln-Tyr : peptide (1:0, 0:1, 1:1, 1:2 and 2:1 on a molar basis) mixtures for DPP-IV inhibition was characterised. Isobolographic analysis showed, in most instances, an additive effect on DPP-IV inhibition. However, a synergistic effect was observed with two Sitagliptin:Ile-Pro-Ile-Gln-Tyr (1:426 and 1:852) mixtures and an antagonistic effect was seen with one Sitagliptin : Trp-Pro (1:852) mixture, and three binary peptide mixtures (Ile-Pro-Ile-Gln-Tyr : Trp-Lys (1:1 and 2:1) and Ile-Pro-Ile-Gln-Tyr:Trp-Leu (1:2)). The results show that Sitagliptin and food protein-derived peptides can interact, thereby enhancing overall DPP-IV inhibition. Combination of Sitagliptin with food protein-derived peptides may help in reducing drug dosage and possible associated side-effects.

An evaluation of three-dimensional modeling of compaction cycles by analyzing the densification behavior of binary and ternary mixtures.

PubMed

Picker, K M; Bikane, F

2001-08-01

The aim of the study is to use the 3D modeling technique of compaction cycles for analysis of binary and ternary mixtures. Three materials with very different deformation and densification characteristics [cellulose acetate (CAC), dicalcium phosphate dihydrate (EM) and theophylline monohydrate (TM)] have been tableted at graded maximum relative densities (rhorel, max) on an eccentric tableting machine. Following that, graded binary mixtures from CAC and EM have been compacted. Finally, the same ratios of CAC and EM have been tableted in a ternary mixture with 20 vol% TM. All compaction cycles have been analyzed by using different data analysis methods. Three-dimensional modeling, conventional determination of the slope of the Heckel function, determination of the elastic recovery during decompression, and calculations according to the pressure-time function were the methods of choice. The results show that the 3D model technique is able to gain the information in one step instead of three different approaches, which is an advantage for formulation development. The results show that this model enables one to better distinguish the compaction properties of mixtures and the interaction of the components in the tablet than 2D models. Furthermore, the information by 3D modeling is more precise since in the slope K of the Heckel-plot (in die) elasticity is included, and in the parameters of the pressure-time function beta and gamma plastic deformation due to pressure is included. The influence of time and pressure on the displacement can now be differentiated.

Thermodynamic scaling of α-relaxation time and viscosity stems from the Johari-Goldstein β-relaxation or the primitive relaxation of the coupling model.

PubMed

Ngai, K L; Habasaki, J; Prevosto, D; Capaccioli, S; Paluch, Marian

2012-07-21

By now it is well established that the structural α-relaxation time, τ(α), of non-associated small molecular and polymeric glass-formers obey thermodynamic scaling. In other words, τ(α) is a function Φ of the product variable, ρ(γ)/T, where ρ is the density and T the temperature. The constant γ as well as the function, τ(α) = Φ(ρ(γ)/T), is material dependent. Actually this dependence of τ(α) on ρ(γ)/T originates from the dependence on the same product variable of the Johari-Goldstein β-relaxation time, τ(β), or the primitive relaxation time, τ(0), of the coupling model. To support this assertion, we give evidences from various sources itemized as follows. (1) The invariance of the relation between τ(α) and τ(β) or τ(0) to widely different combinations of pressure and temperature. (2) Experimental dielectric and viscosity data of glass-forming van der Waals liquids and polymer. (3) Molecular dynamics simulations of binary Lennard-Jones (LJ) models, the Lewis-Wahnström model of ortho-terphenyl, 1,4 polybutadiene, a room temperature ionic liquid, 1-ethyl-3-methylimidazolium nitrate, and a molten salt 2Ca(NO(3))(2)·3KNO(3) (CKN). (4) Both diffusivity and structural relaxation time, as well as the breakdown of Stokes-Einstein relation in CKN obey thermodynamic scaling by ρ(γ)/T with the same γ. (5) In polymers, the chain normal mode relaxation time, τ(N), is another function of ρ(γ)/T with the same γ as segmental relaxation time τ(α). (6) While the data of τ(α) from simulations for the full LJ binary mixture obey very well the thermodynamic scaling, it is strongly violated when the LJ interaction potential is truncated beyond typical inter-particle distance, although in both cases the repulsive pair potentials coincide for some distances.

Evaluation of alfalfa-tall fescue mixtures across multiple environments

USDA-ARS?s Scientific Manuscript database

Binary grass-legume mixtures can benefit forage production systems in different ways helping growers cope both with increasing input costs (e.g., N fertilizer, herbicides) and potentially more variable weather. The main objective of this study was to evaluate alfalfa (Medicago sativa L.) and tall f...

Metal/ceramic composites with high hydrogen permeability

DOEpatents

Dorris, Stephen E.; Lee, Tae H.; Balachandran, Uthamalingam

2003-05-27

A membrane for separating hydrogen from fluids is provided comprising a sintered homogenous mixture of a ceramic composition and a metal. The metal may be palladium, niobium, tantalum, vanadium, or zirconium or a binary mixture of palladium with another metal such as niobium, silver, tantalum, vanadium, or zirconium.

Investigation of Drug–Polymer Compatibility Using Chemometric-Assisted UV-Spectrophotometry

PubMed Central

Mohamed, Amir Ibrahim; Abd-Motagaly, Amr Mohamed Elsayed; Ahmed, Osama A. A.; Amin, Suzan; Mohamed Ali, Alaa Ibrahim

2017-01-01

A simple chemometric-assisted UV-spectrophotometric method was used to study the compatibility of clindamycin hydrochloride (HC1) with two commonly used natural controlled-release polymers, alginate (Ag) and chitosan (Ch). Standard mixtures containing 1:1, 1:2, and 1:0.5 w/w drug–polymer ratios were prepared and UV scanned. A calibration model was developed with partial least square (PLS) regression analysis for each polymer separately. Then, test mixtures containing 1:1 w/w drug–polymer ratios with different sets of drug concentrations were prepared. These were UV scanned initially and after three and seven days of storage at 25 °C. Using the calibration model, the drug recovery percent was estimated and a decrease in concentration of 10% or more from initial concentration was considered to indicate instability. PLS models with PC3 (for Ag) and PC2 (for Ch) showed a good correlation between actual and found values with root mean square error of cross validation (RMSECV) of 0.00284 and 0.01228, and calibration coefficient (R2) values of 0.996 and 0.942, respectively. The average drug recovery percent after three and seven days was 98.1 ± 2.9 and 95.4 ± 4.0 (for Ag), and 97.3 ± 2.1 and 91.4 ± 3.8 (for Ch), which suggests more drug compatibility with an Ag than a Ch polymer. Conventional techniques including DSC, XRD, FTIR, and in vitro minimum inhibitory concentration (MIC) for (1:1) drug–polymer mixtures were also performed to confirm clindamycin compatibility with Ag and Ch polymers. PMID:28275214

High temperature concrete composites containing organosiloxane crosslinked copolymers

DOEpatents

Zeldin, Arkady; Carciello, Neal; Kukacka, Lawrence; Fontana, Jack

1980-01-01

This invention relates to high temperature polymer concrete composites comprising about 10-30% by weight of a liquid monomer mixture consisting essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures theroef; and about 70-90% by weight of an inert inorganic filler system containing silica sand and preferably a member selected from the group consisting of portland cement, Fe.sub.2 O.sub.3, carbon black and mixtures thereof; and optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

Binary mixtures of condensates in generic confining potentials

NASA Astrophysics Data System (ADS)

Facchi, P.; Florio, G.; Pascazio, S.; Pepe, F. V.

2011-12-01

We study a binary mixture of Bose-Einstein condensates, confined in a generic potential, in the Thomas-Fermi approximation. We search for the zero-temperature ground state of the system, both in the case of fixed numbers of particles and fixed chemical potentials. For generic potentials, we analyze the transition from mixed to separated ground-state configurations as the inter-species interaction increases. We derive a simple formula that enables one to determine the location of the domain walls. Finally, we find criteria for the energetic stability of separated configurations, depending on the number and the position of the domain walls separating the two species.

Sol-gel type synthesis of Bi.sub.2 (Sr,Ta.sub.2)O.sub.9 using an acetate based system

DOEpatents

Boyle, Timothy J.

1997-01-01

A method of forming a layered-perovskite bismuth-strontium-tantalum oxide (SBT) ferroelectric material is performed by dissolving a bismuth compound in a first solvent to form a first solution, mixing a strontium compound and a tantalum compound to form a binary mixture, dissolving the binary mixture in a second solvent to form a second solution, mixing the first solution with the second solution to form a SBT precursor solution, evaporating the first and second solvents to form a SBT precursor material and subsequently sintering said SBT precursor material in the presence of oxygen.

Sol-gel type synthesis of Bi{sub 2}(Sr,Ta{sub 2})O{sub 9} using an acetate based system

DOEpatents

Boyle, T.J.

1997-11-04

A method of forming a layered-perovskite bismuth-strontium-tantalum oxide (SBT) ferroelectric material is performed by dissolving a bismuth compound in a first solvent to form a first solution, mixing a strontium compound and a tantalum compound to form a binary mixture, dissolving the binary mixture in a second solvent to form a second solution, mixing the first solution with the second solution to form a SBT precursor solution, evaporating the first and second solvents to form a SBT precursor material and subsequently sintering said SBT precursor material in the presence of oxygen. 6 figs.

Transport properties of nonelectrolyte liquid mixtures—VI. Viscosimetric study of binary mixtures of hexafluorobenzene with aromatic hydrocarbons

NASA Astrophysics Data System (ADS)

Dymond, J. H.; Robertson, J.

1985-01-01

Viscosity coefficients for binary mixtures of hexafluorobenzene with benzene, toluene, para-xylene, and mesitylene have been measured along the saturation line at temperatures from 15 to 120°C using specially designed capillary viscometers. Densities were measured using a pyknometer and volume-change apparatus. Deviations of the viscosities from a rectilinear dependence on mole fraction are consistent with enhanced interactions between unlike species, which increase with increasing number of methyl groups on the aromatic hydrocarbon and decrease with increasing temperature. The application of the Grunberg and Nissan equation, the Hildebrand equation, and energy of activation theories to these results is examined.

Theory of anomalous critical-cluster content in high-pressure binary nucleation.

PubMed

Kalikmanov, V I; Labetski, D G

2007-02-23

Nucleation experiments in binary (a-b) mixtures, when component a is supersaturated and b (carrier gas) is undersaturated, reveal that for some mixtures at high pressures the a content of the critical cluster dramatically decreases with pressure contrary to expectations based on classical nucleation theory. We show that this phenomenon is a manifestation of the dominant role of the unlike interactions at high pressures resulting in the negative partial molar volume of component a in the vapor phase beyond the compensation pressure. The analysis is based on the pressure nucleation theorem for multicomponent systems which is invariant to a nucleation model.

Formation of an amorphous phase and its crystallization in the immiscible Nb-Zr system by mechanical alloying

NASA Astrophysics Data System (ADS)

Al-Aqeeli, N.; Suryanarayana, C.; Hussein, M. A.

2013-10-01

Mechanical alloying of binary Nb-Zr powder mixtures was carried out to evaluate the formation of metastable phases in this immiscible system. The milled powders were characterized for their constitution and structure by X-ray diffraction and transmission electron microscopy methods. It was shown that an amorphous phase had formed on milling the binary powder mixture for about 10 h and that it had crystallized on subsequent milling up to 50-70 h, referred to as mechanical crystallization. Thermodynamic and structural arguments have been presented to explain the formation of the amorphous phase and its subsequent crystallization.

The susceptibility critical exponent for a nonaqueous ionic binary mixture near a consolute point

NASA Technical Reports Server (NTRS)

Zhang, Kai C.; Briggs, Matthew E.; Gammon, Robert W.; Levelt Sengers, J. M. H.

1992-01-01

We report turbidity measurements of a nonaqueous ionic solution of triethyl n-hexylammonium triethyl n-hexylboride in diphenyl ether. A classical susceptibility critical exponent gamma = 1.01 +/- 0.01 is obtained over the reduced temperature range t between values of 0.1 and 0.0001. The best fits of the sample transmission had a standard deviation of 0.39 percent over this range. Ising and spherical model critical exponents are firmly excluded. The correlation length amplitude xi sub 0 from fitting is 1.0 +/- 0.2 nm which is much larger than values found in neutral fluids and some aqueous binary mixtures.

Quantitative analysis of binary polymorphs mixtures of fusidic acid by diffuse reflectance FTIR spectroscopy, diffuse reflectance FT-NIR spectroscopy, Raman spectroscopy and multivariate calibration.

PubMed

Guo, Canyong; Luo, Xuefang; Zhou, Xiaohua; Shi, Beijia; Wang, Juanjuan; Zhao, Jinqi; Zhang, Xiaoxia

2017-06-05

Vibrational spectroscopic techniques such as infrared, near-infrared and Raman spectroscopy have become popular in detecting and quantifying polymorphism of pharmaceutics since they are fast and non-destructive. This study assessed the ability of three vibrational spectroscopy combined with multivariate analysis to quantify a low-content undesired polymorph within a binary polymorphic mixture. Partial least squares (PLS) regression and support vector machine (SVM) regression were employed to build quantitative models. Fusidic acid, a steroidal antibiotic, was used as the model compound. It was found that PLS regression performed slightly better than SVM regression in all the three spectroscopic techniques. Root mean square errors of prediction (RMSEP) were ranging from 0.48% to 1.17% for diffuse reflectance FTIR spectroscopy and 1.60-1.93% for diffuse reflectance FT-NIR spectroscopy and 1.62-2.31% for Raman spectroscopy. The results indicate that diffuse reflectance FTIR spectroscopy offers significant advantages in providing accurate measurement of polymorphic content in the fusidic acid binary mixtures, while Raman spectroscopy is the least accurate technique for quantitative analysis of polymorphs. Copyright © 2017 Elsevier B.V. All rights reserved.

Phase-coexisting patterns, horizontal segregation, and controlled convection in vertically vibrated binary granular mixtures

NASA Astrophysics Data System (ADS)

Ansari, Istafaul Haque; Rivas, Nicolas; Alam, Meheboob

2018-01-01

We report patterns consisting of coexistence of synchronous and asynchronous states [for example, a granular gas co-existing with (i) bouncing bed, (ii) undulatory subharmonic waves, and (iii) Leidenfrost-like states] in experiments on vertically vibrated binary granular mixtures in a Hele-Shaw cell. Most experiments have been carried out with equimolar binary mixtures of glass and steel balls of same diameter by varying the total layer height (F ) for a range of shaking acceleration (Γ ). All patterns as well as the related phase diagram in the (Γ ,F ) plane have been reproduced via molecular dynamics simulations of the same system. The segregation of heavier and lighter particles along the horizontal direction is shown to be the progenitor of such phase-coexisting patterns as confirmed in both experiment and simulation. At strong shaking we uncover a partial convection state in which a pair of convection rolls is found to coexist with a Leidenfrost-like state. The crucial role of the relative number density of two species on controlling the buoyancy-driven granular convection is demonstrated. The onset of horizontal segregation can be explained in terms of an anisotropic diffusion tensor.

UV-Vis spectroscopic study and DFT calculation on the solvent effect of trimethoprim in neat solvents and aqueous mixtures.

PubMed

Almandoz, M C; Sancho, M I; Duchowicz, P R; Blanco, S E

2014-08-14

The solvatochromic behavior of trimethoprim (TMP) was analyzed using UV-Vis spectroscopy and DFT methods in neat and binary aqueous solvent mixtures. The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding interactions on the absorption maxima were evaluated by means of the linear solvation energy relationship concept of Kamlet and Taft. This analysis indicated that both interactions play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra of TMP and TMP:(solvent)n complexes in ACN and H2O using TD-DFT methods were in agreement with the experimental ones. Binary aqueous mixtures containing as co-solvents DMSO, ACN and EtOH were studied. Preferential solvation was detected as a nonideal behavior of the wavenumber curve respective to the analytical mole fraction of co-solvent in all binary systems. TMP molecules were preferentially solvated by the organic solvent over the whole composition range. Index of preferential solvation, as well as the influence of solvent parameters were calculated as a function of solvent composition. Copyright © 2014 Elsevier B.V. All rights reserved.

How do monomeric components of a polymer gel dosimeter respond to ionising radiation: A steady-state radiolysis towards preparation of a 3D polymer gel dosimeter

NASA Astrophysics Data System (ADS)

Kozicki, Marek

2011-12-01

Ionising radiation-induced reactions of aqueous single monomer solutions and mixtures of poly(ethylene glycol) diacrylate (PEGDA) and N, N'-methylenebisacrylamide (Bis) in a steady-state condition are presented below and above gelation doses in order to highlight reactions in irradiated 3D polymer gel dosimeters, which are assigned for radiotherapy dosimetry. Both monomers are shown to undergo radical polymerisation and cross-linking, which result in the measured increase in molecular weight and radius of gyration of the formed polydisperse polymer coils. The formation of nanogels was also observed for Bis solutions at a low concentration. In the case of PEGDA-Bis mixtures, co-polymerisation is suggested as well. At a sufficiently high radiation dose, the formation of a polymer network was observed for both monomers and their mixture. For this reason a sol-gel analysis for PEGDA and Bis was performed gravimetrically and a proposition of an alternative to this method employing a nuclear magnetic resonance technique is made. The two monomers were used for preparation of 3D polymer gel dosimeters having the acronyms PABIG and PABIG nx. The latter is presented for the first time in this work and is a type of the formerly established PABIG polymer gel dosimeter. The elementary characteristics of the new composition are presented, underlining the ease of its preparation, low dose threshold, and slightly increased sensitivity but lower quasi-linear range of dose response in comparison to PABIG.

Development of a Physiologically Based Pharmacokinetic and Pharmacodynamic Model to Determine Dosimetry and Cholinesterase Inhibition for a Binary Mixture of Chlorpyrifos and Diazinon in the Rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timchalk, Chuck; Poet, Torka S.

2008-05-01

Physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) models have been developed and validated for the organophosphorus (OP) insecticides chlorpyrifos (CPF) and diazinon (DZN). Based on similar pharmacokinetic and mode of action properties it is anticipated that these OPs could interact at a number of important metabolic steps including: CYP450 mediated activation/detoxification, and blood/tissue cholinesterase (ChE) binding/inhibition. We developed a binary PBPK/PD model for CPF, DZN and their metabolites based on previously published models for the individual insecticides. The metabolic interactions (CYP450) between CPF and DZN were evaluated in vitro and suggests that CPF is more substantially metabolized to its oxon metabolite than ismore » DZN. These data are consistent with their observed in vivo relative potency (CPF>DZN). Each insecticide inhibited the other’s in vitro metabolism in a concentration-dependent manner. The PBPK model code used to described the metabolism of CPF and DZN was modified to reflect the type of inhibition kinetics (i.e. competitive vs. non-competitive). The binary model was then evaluated against previously published rodent dosimetry and ChE inhibition data for the mixture. The PBPK/PD model simulations of the acute oral exposure to single- (15 mg/kg) vs. binary-mixtures (15+15 mg/kg) of CFP and DZN at this lower dose resulted in no differences in the predicted pharmacokinetics of either the parent OPs or their respective metabolites; whereas, a binary oral dose of CPF+DZN at 60+60 mg/kg did result in observable changes in the DZN pharmacokinetics. Cmax was more reasonably fit by modifying the absorption parameters. It is anticipated that at low environmentally relevant binary doses, most likely to be encountered in occupational or environmental related exposures, that the pharmacokinetics are expected to be linear, and ChE inhibition dose-additive.« less

The thermochemical characteristics of solution of phenol and benzoic acid in water-dimethylsulfoxide and water-acetonitrile mixtures

NASA Astrophysics Data System (ADS)

Zakharov, A. G.; Voronova, M. I.; Batov, D. V.; Smirnova, K. V.

2011-03-01

The solution of phenol and benzoic acid in water-dimethylsulfoxide (DMSO) and water-acetonitrile (AN) mixtures was studied. As distinct from benzoic acid, the thermodynamic characteristics of solution of phenol sharply change at concentrations corresponding to a change in the character of cluster formation in water-DMSO and water-AN mixtures. Differences in the solvation of phenol and benzoic acid are explained by different mechanisms of the interaction of the solutes with clusters existing in binary mixtures.

Collapse in two good solvents, swelling in two poor solvents: defying the laws of polymer solubility?

NASA Astrophysics Data System (ADS)

Mukherji, Debashish; Marques, Carlos M.; Kremer, Kurt

2018-01-01

In this work we discuss two mirror but distinct phenomena of polymer paradoxical properties in mixed solvents: co-non-solvency and co-solvency. When a polymer collapses in a mixture of two miscible good solvents the phenomenon is known as co-non-solvency, while co-solvency is a phenomenon that is associated with the swelling of a polymer in poor solvent mixtures. A typical example of co-non-solvency is provided by poly(N-isopropylacrylamide) in aqueous alcohol, while poly(methyl methacrylate) in aqueous alcohol shows co-solvency. We discuss these two phenomena to compare their microscopic origins and show that both can be understood within generic universal concepts. A broad range of polymers is therefore expected to exhibit these phenomena where specific chemical details play a lesser role than the appropriate combination of interactions between the trio of molecular components.

Chain confinement, phase transitions, and lamellar structure in semicrystalline polymers, polymer blends and polymer nanocomposites

NASA Astrophysics Data System (ADS)

Chen, Huipeng

Recent studies suggest that there are three phase fractions in semicrystalline polymers, the crystalline, the mobile amorphous and the rigid amorphous phases. Due to the distinct properties of the rigid amorphous fraction, RAF, it has been investigated for more than twenty years. In this thesis, a general method using quasi-isothermal temperature-modulated differential scaning calorimetry, DSC, is provided for the first time to obtain the temperature dependent RAF and the other two fractions, crystalline fraction and mobile amorphous fraction, MAF. For poly(ethylene terephthalate), PET, our results show RAF was vitrified during quasi-isothermal cooling after crystallization had been completed and became totally devitrified during quasi-isothermal heating before the start of melting. Several years after people initially discovered the existence of RAF, another issue arose relating to the physical location of RAF and mobile amorphous fraction, MAF, within a lamellar stack model. Two very different models to describe the location of RAF were proposed. In the Heterogeneous Stack Model, HET, RAF is located outside the lamellar stacks. In the Homogeneous Stack Model, HSM, RAF was located inside the lamellar stacks. To determine the lamellar structure of semicrystalline polymers comprising three phase, a general method is given in this thesis by using a combination of the DSC and small angle X-ray scattering, SAXS techniques. It has been applied to Nylon 6, isotactic polystyrene, iPS, and PET. It was found for all of these materials, the HSM model is correct to describe the lamellar structure. In addition to the determination of lamellar structures, this method can also provide the exact fraction of MAF inside and outside lamellar stacks for binary polymer blends. For binary polymer blends, MAF, normally is located partially inside and partially outside the lamellar stacks. However, the quantification of the MAF inside and outside the lamellar stacks has now been provided and is applied to the iPS/atactic polystyrene, aPS, blends. The fractions of MAF inside and outside the lamellar stacks were quantified for the first time. For A/B binary polymer blends, it has been reported that if B is already crystalline, the crystalline fraction would serve as a restriction on the subsequent growth of the crystallizable partner A, while amorphous fraction could be diffused from the crystalline growth front of the crystallizing A component. Considering the effect of RAF on binary blends, a new concept is provided: like the crystals, the RAF of one polymer component may inhibit the growth of crystals of the other blend partner. The non-isothermal crystallization of PET/poly(lactic acid), PLA, blends were investigated and the results confirmed the new concept is correct: PET forms a large amount of RAF and inhibits crystal formation in PLA. Then, we broadened the concept of RAF and investigated the RAF in recent 'hot' materials, polymer nanocomposites. It was found the fraction of RAF greatly increased with a small amount of multi-wall carbon nanotubes, MWCNT, loading in PET electrospun, ES, fibers. A general model is given for polymer ES fibers with MWCNTs: the addition of MWCNTs causes polymer chains in the ES fibers to become more extended, (ie, more stretched), resulting in more confinement of PET chains and an increase in the RAF.

Effects of drug-carrier interactions on drug dissolution from binary and ternary matrices

NASA Astrophysics Data System (ADS)

Iqbal, Zafar

For nearly five decades, pharmaceutical researchers have studied solid solutions of drugs in polymers as a potential means to enhance the dissolution of drugs with poor aqueous solubility. This has become of greater importance in recent years because most new potential drug compounds (new chemical entities) exhibit poor water solubility and present great challenges to scientists who must design dosage forms from which the drugs are bioavailable. During the formulation of a solid solution, the drug undergoes physical but not chemical alterations that increase its chemical potential in the formulation relative to that of the pure drug in its stable form. This increased chemical potential is responsible for enhanced dissolution as well as physical instabilities, such as amorphous to crystalline conversions and precipitation within the solid state. The chemical potential is derived from the Gibbs free energy, so it is reasonable to explain the behavior of solid solution systems in terms of thermodynamics. Solid solutions and dispersions have been extensively studied by pharmaceutical scientists, both with regard to manufacturing aspects and the proposal of various models in attempts to explain the physical bases for how these systems work. Recently, Dave and Bellantone proposed a model based on the thermodynamic changes resulting from the formulation of binary solid solutions of a drug in the polymer PVP. Their model introduced a modification of the F-H theory, which was used to quantify the drug-polymer interaction energies and calculate the entropy of mixing of the drug and polymer. In this work, the model of Dave and Bellantone was extended to include three-component systems, consisting of one drug mixed in a carrier matrix consisting of mixture of two polymers or a polymer and a surfactant. For this research, solid solutions were formed using various drug weight fractions in the formulations. The study focused on the following points: (1) Prepare solid solution formulations and perform appropriate physical characterizations. (2) Characterize the increase in drug dissolution rates resulting from solid solution formulations. (3) Relate the initial dissolution rates to the drug solubility. (4) Explain the solubility enhancement from solid solution dosage in terms of the drug polymer interactions using the extended thermodynamic model. Two poorly water soluble drugs, levonorgestrel (LEVO) and ethinyl estradiol (EE) were formulated in seven solid solution preparations comprised of four carrier systems. Materials used as carriers included various combinations of the polymers PVP K-30, Copovidone (COP), Poloxamer 182, and the surfactant TweenRTM 20. Additionally, ibuprofen (IBU) was used in three formulations consisting of various combinations of PVP K-30, Copovidone and TweenRTM 20. Formulations with various drug weight fractions (0.5%--30%) were prepared using the solvent evaporation technique. Each formulation was tested for dissolution using intrinsic dissolution apparatus (USP). The solid solutions were compressed into tablets into the sample die that maintained a constant surface area during the dissolution process. DSC, XRD and NIRS scans identified that the crystalline peaks of the drug disappeared with the addition of the polymer for all ratios of EE, indicating the formation of solid solutions (to within the limits of detection of the equipment). This was also observed for the LEVO dispersions up to 10% drug loading. At higher drug loading, solutions were formed but some small degree crystallinity was also present. For each experiment, the initial dissolution rates were obtained from the slope of the mass dissolved vs. time plots taken at early times, and volume normalized initial dissolution rates RV were calculated by dividing the initial dissolution rate by the volume fraction of the drug in the formulation. Comparison of the RV values for the various formulations with a reference RV (typically that of the pure drug or of the formulation with the highest polymer content) allowed calculation of relative volume normalized dissolution rates (RNV). The various RNV were used in the thermodynamic model for data analyses and to determine the interactions between the drug and carrier molecules. It was generally seen that RNV increased with decreased drug fraction, and was adequately modeled by the equations derived from the extended thermodynamic model. It was concluded that the model proposed for the binary and ternary systems successfully represented the mechanism of drug-polymer interaction and the energy changes taken place within the dispersion systems. The dissolution data analysis and subsequent understanding of physical modifications in the dispersion systems characterized by XRD, NIRS and DSC further substantiated the findings. The understanding of the fundamental physical might help scientists to predict the effects of mixing various drugs and polymers, and the effects of varying ratios.

Gene Expression Responses in Male Fathead Minnows Exposed to Binary Mixtures of an Estrogen and Antiestrogen

EPA Science Inventory

Aquatic organisms are continuously exposed to complex mixtures of chemicals, many of which can interfere with their endocrine system, resulting in impaired reproduction, development or survival, among others. In order to analyze the effects and mechanisms of action of estrogen...

Construction of Lines of Constant Density and Constant Refractive Index for Ternary Liquid Mixtures.

ERIC Educational Resources Information Center

Tasic, Aleksandar Z.; Djordjevic, Bojan D.

1983-01-01

Demonstrates construction of density constant and refractive index constant lines in triangular coordinate system on basis of systematic experimental determinations of density and refractive index for both homogeneous (single-phase) ternary liquid mixtures (of known composition) and the corresponding binary compositions. Background information,…

On ternary species mixing and combustion in isotropic turbulence at high pressure

NASA Astrophysics Data System (ADS)

Lou, Hong; Miller, Richard S.

2004-05-01

Effects of Soret and Dufour cross-diffusion, whereby both concentration and thermal diffusion occur in the presence of mass fraction, temperature, and pressure gradients, are investigated in the context of both binary and ternary species mixing and combustion in isotropic turbulence at large pressure. The compressible flow formulation is based on a cubic real-gas state equation, and includes generalized forms for heat and mass diffusion derived from nonequilibrium thermodynamics and fluctuation theory. A previously derived formulation of the generalized binary species heat and mass fluxes is first extended to the case of ternary species, and appropriate treatment of the thermal and mass diffusion factors is described. Direct numerical simulations (DNS) are then conducted for both binary and ternary species mixing and combustion in stationary isotropic turbulence. Mean flow temperatures and pressures of =700 K and =45 atm are considered to ensure that all species mixtures remain in the supercritical state such that phase changes do not occur. DNS of ternary species systems undergoing both pure mixing and a simple chemical reaction of the form O2+N2→2NO are then conducted. It is shown that stationary scalar states previously observed for binary mixing persist for the ternary species problem as well; however, the production and magnitude of the scalar variance is found to be altered for the intermediate molecular weight species as compared to the binary species case. The intermediate molecular weight species produces a substantially smaller scalar variance than the remaining species for all flows considered. For combustion of nonstoichiometric mixtures, a binary species mixture, characterized by stationary scalar states, results at long times after the lean reactant is depleted. The form of this final scalar distribution is observed to be similar to that found in the binary flow situation. A series of lower resolution simulations for a variety of species is then used to show the dependence of the stationary scalar variance on the turbulence Reynolds number, turbulence Mach number, species molecular weight ratio, and relative proportion of two species present in the flow after completion of combustion.

Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics

DOE PAGES

Tsui, Lok-kun; Benavidez, Angelica; Palanisamy, Ponnusamy; ...

2017-04-13

The development of on-board sensors for emissions monitoring is necessary for continuous monitoring of the performance of catalytic systems in automobiles. We have fabricated mixed potential electrochemical gas sensing devices with Pt, La 0.8Sr 0.2CrO 3 (LSCO), and Au/Pd alloy electrodes and a porous yttria-stabilized zirconia electrolyte. The three-electrode design takes advantage of the preferential selectivity of the Pt + Au/Pd and Pt + LSCO pairs towards different species of gases and has additional tunable selectivity achieved by applying a current bias to the latter pair. Voltages were recorded in single, binary, and ternary gas streams of NO, NO 2,more » C 3H 8, and CO. We have also trained artificial neural networks to examine the voltage output from sensors in biased and unbiased modes to both identify which single test gas or binary mixture of two test gases is present in a gas stream as well as extract concentration values. We were then able to identify single and binary mixtures of these gases with accuracy of at least 98%. For determining concentration, the peak in the error distribution for binary mixtures was 5% and 80% of test data fell under <12% error. The sensor stability was also evaluated over the course of over 100 days and the ability to retrain ANNs with a small dataset was demonstrated.« less

Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsui, Lok-kun; Benavidez, Angelica; Palanisamy, Ponnusamy

The development of on-board sensors for emissions monitoring is necessary for continuous monitoring of the performance of catalytic systems in automobiles. We have fabricated mixed potential electrochemical gas sensing devices with Pt, La 0.8Sr 0.2CrO 3 (LSCO), and Au/Pd alloy electrodes and a porous yttria-stabilized zirconia electrolyte. The three-electrode design takes advantage of the preferential selectivity of the Pt + Au/Pd and Pt + LSCO pairs towards different species of gases and has additional tunable selectivity achieved by applying a current bias to the latter pair. Voltages were recorded in single, binary, and ternary gas streams of NO, NO 2,more » C 3H 8, and CO. We have also trained artificial neural networks to examine the voltage output from sensors in biased and unbiased modes to both identify which single test gas or binary mixture of two test gases is present in a gas stream as well as extract concentration values. We were then able to identify single and binary mixtures of these gases with accuracy of at least 98%. For determining concentration, the peak in the error distribution for binary mixtures was 5% and 80% of test data fell under <12% error. The sensor stability was also evaluated over the course of over 100 days and the ability to retrain ANNs with a small dataset was demonstrated.« less

Thermodynamic analysis of solid-fuel mixtures glycidyl azide polymer (GAP)/RDX for miniengines of microelectromechanical systems

NASA Astrophysics Data System (ADS)

Fut'ko, S. I.; Ermolaeva, E. M.; Dobrego, K. V.; Bondarenko, V. P.; Dolgii, L. N.

2011-09-01

On the basis of thermodynamic calculations we show that solid-fuel mixtures glycidyl azide polymer/RDX are promising for use in miniengines made on the basis of technologies of microelectromechanical systems of semiconductor microelectronics. It has been shown that small (up to 20 mass percent) additives of RDX to the glycidyl azide polymer markedly increase the values of the theoretical specific impulse and the thermal efficiency of the engine and decrease the quantity of undesirable solid carbon formed in combustion products of the mixed fuel. In so doing, these mixtures provide fairly low combustion temperatures not exceeding the thermostability limit of crystal silicon from which the miniengine case is made. The physicochemical factors influencing the value of the theoretical specific impulse of the mixed solid-fuel charge have been elucidated, and methods for its maximization have been proposed.

Development of critical molecular weight-property specifications for high performance polymers used as adhesives and composites

NASA Technical Reports Server (NTRS)

Kranbuehl, D. E.

1982-01-01

The polyimide resin, LARC-160, was prepared from diethyl-3, 3', 4,4'-benzophenone tetracarboxylate, ethyl-5-norbornene-2,3-dicarboxylate and Jeffamine AP-22. The imidization reactions of NE and BTDE were studied by HPLC, C-13-NMR and IR. NE imidizes slowly at 12 C; BTDE imidizes when the resin is heated above 100 C. Both imidization reactions proceed directly to the imide. Neither amic acid is present in significant quantities at any stage of the imidization reactions. The monomer mixture was stored at 12 C for periods up to 14 months. The effects of resin aging at this temperature on the chemical composition of the resin monomer mixture and the imidized polymer formed on curing were investigated. Aging the resin monomer mixture has the effect of partially advancing the imidization reaction. The average size of the cured polymer increases slightly with resin age.

Colloid-polymer mixtures under slit confinement.

PubMed

Pérez-Ramírez, Allan; Figueroa-Gerstenmaier, Susana; Odriozola, Gerardo

2017-03-14

We report a NVT molecular dynamic study of colloid-polymer mixtures under slit confinement. For this purpose, we are employing the Asakura-Oosawa model for studying colloidal particles, polymer coils, and hard walls as the external confining field. The colloid-polymer size ratio, q, is varied in the range 1⩾q⩾0.4 and the confinement distance, H, in 10σ c ⩾H⩾3σ c , σ c being the colloidal diameter. Vapor-liquid coexistence properties are assessed, from which phase diagrams are built. The obtained data fulfill the corresponding states law for a constant H when q is varied. The shift of the polymer and colloidal chemical potentials of coexistence follows a linear relationship with (H-σ c ) -1 for H≳4σ c . The confined vapor-liquid interfaces can be fitted with a semicircular line of curvature (H-σ c ) -1 , from which the contact angle can be obtained. We observe complete wetting of the confining walls for reservoir polymer concentrations above and close to the critical value, and partial wetting for reservoir polymer concentrations above and far from it.

Theory of competitive solvation of polymers by two solvents and entropy-enthalpy compensation in the solvation free energy upon dilution with the second solvent.

PubMed

Dudowicz, Jacek; Freed, Karl F; Douglas, Jack F

2015-06-07

We develop a statistical mechanical lattice theory for polymer solvation by a pair of relatively low molar mass solvents that compete for binding to the polymer backbone. A theory for the equilibrium mixture of solvated polymer clusters {AiBCj} and free unassociated molecules A, B, and C is formulated in the spirit of Flory-Huggins mean-field approximation. This theoretical framework enables us to derive expressions for the boundaries for phase stability (spinodals) and other basic properties of these polymer solutions: the internal energy U, entropy S, specific heat CV, extent of solvation Φsolv, average degree of solvation 〈Nsolv〉, and second osmotic virial coefficient B2 as functions of temperature and the composition of the mixture. Our theory predicts many new phenomena, but the current paper applies the theory to describe the entropy-enthalpy compensation in the free energy of polymer solvation, a phenomenon observed for many years without theoretical explanation and with significant relevance to liquid chromatography and other polymer separation methods.

Phase Behavior of Pyrene and Vinyl Polymers with Aromatic Side Groups

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kangovi, Gagan N.; Lee, Sangwoo

The phase behavior and thermodynamic properties of mixtures of pyrene and model vinyl polymers with and without aromatic side groups are investigated using differential scanning calorimetry (DSC) measurements. The melting temperature and associated heat of melting of the pyrene crystals in the mixtures are utilized to extract the effective interaction parameters χ and the composition of polymer-rich phases, respectively. The χ of pyrene mixed with polymers with aromatic side groups investigated in this study, polystyrene, poly(2-vinylpyridine), and poly(3-vinylanisole), is less than 0.5 at the melting point of the pyrene crystals, suggesting that pyrene and the polymers with aromatic sides groupsmore » are enthalpically compatible, likely due to aromatic π–π interactions. In contrast, the χ of pyrene mixed with poly(1,4-isoprene) or poly(ethylene-alt-propylene) is larger than 0.5. The DSC measurements also enable characterization of the composition of polymer-rich phases. Interestingly, the polymers with aromatic side groups are found to have more pronounced miscibility with pyrene at symmetric compositions.« less

Colloid-polymer mixtures under slit confinement

NASA Astrophysics Data System (ADS)

Pérez-Ramírez, Allan; Figueroa-Gerstenmaier, Susana; Odriozola, Gerardo

2017-03-01

We report a NVT molecular dynamic study of colloid-polymer mixtures under slit confinement. For this purpose, we are employing the Asakura-Oosawa model for studying colloidal particles, polymer coils, and hard walls as the external confining field. The colloid-polymer size ratio, q, is varied in the range 1 ⩾q ⩾0.4 and the confinement distance, H, in 10 σc ⩾H ⩾3 σc , σc being the colloidal diameter. Vapor-liquid coexistence properties are assessed, from which phase diagrams are built. The obtained data fulfill the corresponding states law for a constant H when q is varied. The shift of the polymer and colloidal chemical potentials of coexistence follows a linear relationship with (H-σc ) -1 for H ≳4 σc . The confined vapor-liquid interfaces can be fitted with a semicircular line of curvature (H-σc ) -1, from which the contact angle can be obtained. We observe complete wetting of the confining walls for reservoir polymer concentrations above and close to the critical value, and partial wetting for reservoir polymer concentrations above and far from it.

Statistical Mechanical Theory of Penetrant Diffusion in Polymer Melts and Glasses

NASA Astrophysics Data System (ADS)

Zhang, Rui; Schweizer, Kenneth

We generalize our force-level, self-consistent nonlinear Langevin equation theory of activated diffusion of a dilute spherical penetrant in hard sphere fluids to predict the long-time diffusivity of molecular penetrants in supercooled polymer liquids and non-aging glasses. Chemical complexity is treated using an a priori mapping to a temperature-dependent hard sphere mixture model where polymers are disconnected into effective spheres based on the Kuhn length as the relevant coarse graining scale. A key parameter for mobility is the penetrant to polymer segment diameter ratio, R. Our calculations agree well with experimental measurements for a wide range of temperatures, penetrant sizes (from gas molecules with R ~0.3 to aromatic molecules with R ~1) and diverse amorphous polymers, over 10 decades variation of penetrant diffusivity. Structural parameter transferability is good. We have also formulated a theory at finite penetrant loading for the coupled penetrant-polymer dynamics in chemically (nearly) matched mixtures (e.g., toluene-polystyrene) which captures well the increase of penetrant diffusivity and decrease of polymer matrix vitrification temperature with increasing loading.

Rock Content Influence on Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Parajuli, K.; Sadeghi, M.; Jones, S. B.

2015-12-01

Soil hydraulic properties including the soil water retention curve (SWRC) and hydraulic conductivity function are important characteristics of soil affecting a variety of soil properties and processes. The hydraulic properties are commonly measured for seived soils (i.e. particles < 2 mm), but many natural soils include rock fragments of varying size that alter bulk hydraulic properties. Relatively few studies have addressed this important problem using physically-based concepts. Motivated by this knowledge gap, we set out to describe soil hydraulic properties using binary mixtures (i.e. rock fragment inclusions in a soil matrix) based on individual properties of the rock and soil. As a first step of this study, special attention was devoted to the SWRC, where the impact of rock content on the SWRC was quantified using laboratory experiments for six different mixing ratios of soil matrix and rock. The SWRC for each mixture was obtained from water mass and water potential measurements. The resulting data for the studied mixtures yielded a family of SWRC indicating how the SWRC of the mixture is related to that of the individual media, i.e., soil and rock. A consistent model was also developed to describe the hydraulic properties of the mixture as a function of the individual properties of the rock and soil matrix. Key words: Soil hydraulic properties, rock content, binary mixture, experimental data.

Treatment System for Removing Halogenated Compounds from Contaminated Sources

NASA Technical Reports Server (NTRS)

Clausen, Christian A. (Inventor); Yestrebsky, Cherie L. (Inventor); Quinn, Jacqueline W. (Inventor)

2015-01-01

A treatment system and a method for removal of at least one halogenated compound, such as PCBs, found in contaminated systems are provided. The treatment system includes a polymer blanket for receiving at least one non-polar solvent. The halogenated compound permeates into or through a wall of the polymer blanket where it is solubilized with at least one non-polar solvent received by said polymer blanket forming a halogenated solvent mixture. This treatment system and method provides for the in situ removal of halogenated compounds from the contaminated system. In one embodiment, the halogenated solvent mixture is subjected to subsequent processes which destroy and/or degrade the halogenated compound.

Single-step generation of metal-plasma polymer multicore@shell nanoparticles from the gas phase.

PubMed

Solař, Pavel; Polonskyi, Oleksandr; Olbricht, Ansgar; Hinz, Alexander; Shelemin, Artem; Kylián, Ondřej; Choukourov, Andrei; Faupel, Franz; Biederman, Hynek

2017-08-17

Nanoparticles composed of multiple silver cores and a plasma polymer shell (multicore@shell) were prepared in a single step with a gas aggregation cluster source operating with Ar/hexamethyldisiloxane mixtures and optionally oxygen. The size distribution of the metal inclusions as well as the chemical composition and the thickness of the shells were found to be controlled by the composition of the working gas mixture. Shell matrices ranging from organosilicon plasma polymer to nearly stoichiometric SiO 2 were obtained. The method allows facile fabrication of multicore@shell nanoparticles with tailored functional properties, as demonstrated here with the optical response.

Degradable conjugated polymers for the selective sorting of semiconducting carbon nanotubes

DOEpatents

Gopalan, Padma; Arnold, Michael Scott; Kansiusarulsamy, Catherine Kanimozhi; Brady, Gerald Joseph; Shea, Matthew John

2018-04-10

Conjugated polymers composed of bi-pyridine units linked to 9,9-dialkyl fluorenyl-2,7-diyl units via imine linkages along the polymer backbone are provided. Also provided are semiconducting single-walled carbon nanotubes coated with the conjugated polymers and methods of sorting and separating s-SWCNTs from a sample comprising a mixture of s-SWCNTs and metallic single-walled carbon nanotubes using the conjugated polymers.

Reentrant equilibrium disordering in nanoparticle–polymer mixtures

DOE PAGES

Meng, Dong; Kumar, Sanat K.; Grest, Gary S.; ...

2017-01-31

A large body of experimental work has established that athermal colloid/polymer mixtures undergo a sequence of transitions from a disordered fluid state to a colloidal crystal to a second disordered phase with increasing polymer concentration. These transitions are driven by polymer-mediated interparticle attraction, which is a function of both the polymer density and size. It has been posited that the disordered state at high polymer density is a consequence of strong interparticle attractions that kinetically inhibit the formation of the colloidal crystal, i.e., the formation of a non-equilibrium gel phase interferes with crystallization. Here we use molecular dynamics simulations andmore » density functional theory on polymers and nanoparticles (NPs) of comparable size and show that the crystal-disordered phase coexistence at high polymer density for sufficiently long chains corresponds to an equilibrium thermodynamic phase transition. While the crystal is, indeed, stabilized at intermediate polymer density by polymer-induced intercolloid attractions, it is destabilized at higher densities because long chains lose significant configurational entropy when they are forced to occupy all of the crystal voids. Finally, our results are in quantitative agreement with existing experimental data and show that, at least in the nanoparticle limit of sufficiently small colloidal particles, the crystal phase only has a modest range of thermodynamic stability.« less

Monte Carlo simulations of mixtures involving ketones and aldehydes by a direct bubble pressure calculation.

PubMed

Ferrando, Nicolas; Lachet, Véronique; Boutin, Anne

2010-07-08

Ketone and aldehyde molecules are involved in a large variety of industrial applications. Because they are mainly present mixed with other compounds, the prediction of phase equilibrium of mixtures involving these classes of molecules is of first interest particularly to design and optimize separation processes. The main goal of this work is to propose a transferable force field for ketones and aldehydes that allows accurate molecular simulations of not only pure compounds but also complex mixtures. The proposed force field is based on the anisotropic united-atoms AUA4 potential developed for hydrocarbons, and it introduces only one new atom, the carbonyl oxygen. The Lennard-Jones parameters of this oxygen atom have been adjusted on saturated thermodynamic properties of both acetone and acetaldehyde. To simulate mixtures, Monte Carlo simulations are carried out in a specific pseudoensemble which allows a direct calculation of the bubble pressure. For polar mixtures involved in this study, we show that this approach is an interesting alternative to classical calculations in the isothermal-isobaric Gibbs ensemble. The pressure-composition diagrams of polar + polar and polar + nonpolar binary mixtures are well reproduced. Mutual solubilities as well as azeotrope location, if present, are accurately predicted without any empirical binary interaction parameters or readjustment. Such result highlights the transferability of the proposed force field, which is an essential feature toward the simulation of complex oxygenated mixtures of industrial interest.

Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

DOEpatents

Sugama, Toshifumi; Kukacka, Lawrence E.; Horn, William H.

1985-01-01

Quick setting polymer concrete compositions with excellent structural properties are disclosed; these polymer concrete compositions are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate, which may be wet, and with a source of bivalent metallic ions.