WorldWideScience

Sample records for cryolite type mixtures

  1. Electrical Conductivity of Cryolite Melts

    Science.gov (United States)

    Fellner, P.; Grjotheim, K.; Kvande, H.

    1985-11-01

    This paper proposes an equation for the electrical conductivity of multicomponent cryolite-based mixtures. The equation is based on a physical model which assumes that the conductivity is proportional to the number density of the effective electric charges in the melt. The various authors in the available literature show a great discrepancy in conductivity data of cryolite-based melts. The equation based on the physical model enables determination of which set of data is preferable. Special consideration in this respect is given to the influence of magnesium flouride and lithium flouride additions to the melt.

  2. Remarkable Strontium B-Site Occupancy in FerroelectricPb(Zr1-xTix)O3 Solid Solutions Doped with Cryolite-Type StrontiumNiobate

    Energy Technology Data Exchange (ETDEWEB)

    Feltz, A.; Schmidt-Winkel, P.; Schossman, M.; Booth, C.H.; Albering, J.

    2007-04-26

    New high-performance ferroelectric materials based on Pb(Zr{sub 1-x}Ti{sub x})O{sub 3} (PZT) that are doped with cryolite-type strontium niobate (SNO, Sr{sub 4}(Sr{sub 2-2y/3}Nb{sub 2+2y/3})O{sub 11+y}V{sub 0,1-y} with 0 {le} y {le} 1), hence denoted PZT:SNO, and their microscopic structure are described. The combination of exceptional piezoelectric properties, i.e. a piezoelectric strain constant of d{sub 33} {approx} 760 pm/V, with excellent stability and degradation resistance makes ferroelectric PZT:SNO solid solutions very attractive for use in novel and innovative piezoelectric actuator and transducer applications. Extended X-ray absorption fine-structure (EXAFS) analyses of PZT:SNO samples revealed that {approx}10 % of the Sr cations occupy the nominal B-sites of the perovskite-type PZT host lattice. This result was supported by EXAFS analyses of both a canonical SrTiO{sub 3} perovskite and two SNO model and reference compounds. Fit models that do not account for Sr cations on B-sites were ruled out. A clear Sr-Pb peak in Fourier transformed EXAFS data visually confirmed this structural model. The generation of temporary oxygen vacancies and the intricate defect chemistry induced by SNO-doping of PZT are crucial for the exceptional materials properties exhibited by PZT:SNO materials.

  3. Fluid geochemistry in the Ivigtut cryolite deposit, South Greenland

    Science.gov (United States)

    Köhler, Jasmin; Konnerup-Madsen, Jens; Markl, Gregor

    2008-07-01

    The 1.27 Ga old Ivigtut (Ivittuut) intrusion in South Greenland is world-famous for its hydrothermal cryolite deposit [Na 3AlF 6] situated within a strongly metasomatised A-type granite stock. This detailed fluid inclusion study characterises the fluid present during the formation of the cryolite deposit and thermodynamic modelling allows to constrain its formation conditions. Microthermometry revealed three different types of inclusions: (1) pure CO 2, (2) aqueous-carbonic and (3) saline-aqueous inclusions. Melting temperatures range between - 23 and - 15 °C for type 2 and from - 15 to - 10 °C for type 3 inclusions. Most inclusions homogenise between 110 and 150 °C into the liquid. Stable isotope compositions of CO 2 and H 2O were measured from crushed inclusions in quartz, cryolite, fluorite and siderite. The δ13C values of about - 5‰ PDB are typical of mantle-derived magmas. The differences between δ18O of CO 2 (+ 21 to + 42‰ VSMOW) and δ18O of H 2O (- 1 to - 21.7‰ VSMOW) suggest low-temperature isotope exchange. δD (H 2O) ranges from - 19 to - 144‰ VSMOW. The isotopic composition of inclusion water closely follows the meteoric water line and is comparable to Canadian Shield brines. Ion chromatography revealed the fluid's predominance in Na, Cl and F. Cl/Br ratios range between 56 and 110 and may imply intensive fluid-rock interaction with the host granite. Isochores deduced from microthermometry in conjunction with estimates for the solidification of the Ivigtut granite suggest a formation pressure of approximately 1-1.5 kbar for the fluid inclusions. Formation temperatures of different types of fluid inclusions vary between 100 and 400 °C. Thermodynamic modelling of phase assemblages and the extraordinary high concentration in F (and Na) may indicate that the cryolite body and its associated fluid inclusions could have formed during the continuous transition from a volatile-rich melt to a solute-rich fluid.

  4. 76 FR 31606 - Cryolite Registration Review Docket; Extension of Comment Period

    Science.gov (United States)

    2011-06-01

    ... AGENCY Cryolite Registration Review Docket; Extension of Comment Period AGENCY: Environmental Protection Agency (EPA). ACTION: Notice; extension of comment period. SUMMARY: EPA issued a notice in the Federal... comment, including cryolite. This document extends the comment period for the cryolite registration review...

  5. Cross-sectional study of health effects of cryolite production

    DEFF Research Database (Denmark)

    Friis, Henrik; Clausen, J; Gyntelberg, F

    1989-01-01

    -related exposure and lung function. Many cryolite workers described a group of symptoms appearing after 15 to 30 min of heavy dust exposure: nausea, followed by epigastric pain with relief after spontaneous or provoked vomiting. Thirty-four (33.6 per cent) workers complained of nausea, vomiting or diarrhoea...

  6. The calcium fluoride effect on properties of cryolite melts feasible for low-temperature production of aluminum and its alloys

    Science.gov (United States)

    Tkacheva, O.; Dedyukhin, A.; Redkin, A.; Zaikov, Yu.

    2017-07-01

    The CaF2 effect on the liquidus temperature, electrical conductivity and alumina solubility in the potassium-sodium and potassium-lithium cryolite melts with cryolite ratio (CR = (nKF+nMF)/nAlF3, M = Li, Na) 1.3 was studied. The liquidus temperature in the quisi-binary system [KF-LiF-AlF3]-CaF2 changes with the same manner as in the [KF-NaF-AlF3]-CaF2. The electrical conductivity in the KF-NaF-AlF3-CaF2 melt decreases with increasing the CaF2 content, but it slightly raises with the first small addition of CaF2 into the KF-LiF-AlF3-CaF2 melts, enriched with KF, which was explained by the increased K+ ions mobility due to their relatively low ionic potential. The contribution of the Li+ cations in conductivity of the KF-LiF-AlF3-CaF2 electrolyte is not noteworthy. The Al2O3 solubility in the KF-NaF-AlF3 electrolyte rises with the increasing KF content, but the opposite tendency is observed in the cryolite mixtures containing CaF2. The insoluble compounds - KCaAl2F9 or KCaF3 - formed in the molten mixtures containing potassium and calcium ions endorse the increase of the liquidus temperature. The calcium fluoride effect on the side ledge formation in the electrolytic cell during low-temperature aluminum electrolysis is discussed.

  7. Study of cryolite preparation from fluoride-containing acid slag in aluminium industry

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new process of cryolite preparation is studied in this work by selecting a proper system of reaction and weeding impurity technology. The quality of artifial cryolite reaches and exceeds the first level of national standard. The utilization efficient of fluoride-containing acid slag is above 99.5%. It brings considerable economic benefit, and the environment is improved.

  8. Peltier heats in cryolite melts with alumina

    Energy Technology Data Exchange (ETDEWEB)

    Flem, B.E.; Ratkje, S.K.; Sterten, A. [Univ. of Trondheim (Norway)

    1996-10-01

    The Seebeck coefficient was measured for cells with electrolytes of molten mixtures of sodium fluoride and aluminum fluoride saturated with alumina. The electrodes were either a pair of oxygen electrodes or a pair of aluminum electrodes. For the molar ratio NaF/AlF{sub 3} equal to 1.8, 1.2 and 1.0, the authors obtained the Seebeck coefficients {minus}1.80 mV K{sup {minus}1} at 971 C, {minus}1.63 mV K{sup {minus}1} at 813.6 C and {minus}0.583 mV K{sup {minus}1} at 758 C, respectively, for the oxygen electrodes. For the aluminum electrodes, the authors obtained the Seebeck coefficient {minus}1.23 mV K{sup {minus}1} at 962 C, for the molar ratio NaF/AlF{sub 3} equal to 1.8. The results suggest that there is a substantial reversible heat consumption at the anode during aluminum electrolysis and a large reversible heat production at the cathode. The highest temperature in the Hall-Heroult cell is then closer to the cathode than the anode. The transported entropies of Al{sup 3+} and O{sup 2{minus}} were calculated to be 77 J mol{sup {minus}1} K{sup {minus}1} and 10 J mol{sup {minus}1} K{sup {minus}1}, respectively, when the molar ratio NaF/AlF{sub 3} was equal to 1.0.

  9. Exposure-dependent variation in cryolite induced lethality in the non-target insect, Drosophila melanogaster.

    Science.gov (United States)

    Podder, Sayanti; Roy, Sumedha

    2014-03-01

    The starting point of toxicity testing of any chemical in an organism is the determination of its Lethal Concentration 50 (LC50). In the present study, LC50 of a fluorinated insecticide cryolite is determined in a non-target insect model, Drosophila melanogaster. Interestingly, the result shows that acute LC50 of cryolite was much greater in comparison to the chronic one in case of Drosophila larvae. Larvae which were exposed to 65,000 to 70,000 µg/ml cryolite through food showed 50% mortality after 18 hours of acute exposure, whereas only 150 to 160 µg/ml cryolite was sufficient to cause 50% mortality in case of chronic exposure. Thus cryolite in a small amount when applied once cannot produce noticeable changes in Drosophila, whereas the same amount when used continuously can be fatal. The non-feeding pupal stage was also seen to be affected by chemical treatment. This suggests that the test chemical affects the developmental fate and results in failure of adult emergence. Absence of chemical-induced mortality in adults assumes that the toxicity of cryolite might be restricted to the preimaginal stages of the organism. Reduction in body size of larvae after ingestion of cryolite (with food) in acute treatment schedule is another interesting finding of this study. Some individuals consuming cryolite containing food cannot survive whereas the few survivors manifest a significant growth retardation which might be due to a tendency of refusal in feeding. Hence the present findings provide a scope of assessment of risk of other similar non-target groups.

  10. Environmental monitoring at the cryolite mine in Ivittuut, South Greenland, in 2010

    DEFF Research Database (Denmark)

    Johansen, Poul; Asmund, Gert; Riget, Frank Farsø

    This report evaluates the pollution in Arsuk Fjord at Ivittuut in South Greenland based on environmental studies conducted in 2010. The area is polluted by lead and zinc caused by the mining of cryolite that took place from 1854 to 1987. The 2010 study shows that the lead pollution of the fjord...

  11. Mixture

    Directory of Open Access Journals (Sweden)

    Silva-Aguilar Martín

    2011-01-01

    Full Text Available Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity.

  12. 冰晶石湿料螺旋输送机的故障分析%Fault analysis of screw conveyor for transporting wet material of cryolite

    Institute of Scientific and Technical Information of China (English)

    业文成

    2012-01-01

    LS型螺旋输送机输送冰晶石湿料常发生螺旋轴扭断故障,分析故障产生的原因,介绍为防止螺旋输送机故障在管理、物料及设备方面所采取的整改措施,达到了设备稳定运行的效果。%The LS type screw conveyor for transporting wet material of cryolite screw shaft, the reasons of the fault are analyzed, the rectification measures in usually happen twist off of management, materials and equipment of the action for preventing fault are introduced, achieving the stable operation of the equipment.

  13. Do-Fluoride "Cryolite By- product Carbon White" Awarded the 13th China Excellent Patent Award%Do-Fluoride "Cryolite By- product Carbon White" Awarded the 13th China Excellent Patent Award

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    On November 4, the results of the 13th China Patent Awards were publicized by the State Intellectual Property Office of the People's Republic of China. The patent of "production method of cryolite by-product carbon white" declared by Henan Province Jiaozuo Do-Fluoride Company was awarded China Excellent Patent Award.

  14. Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

    Science.gov (United States)

    Latino, Diogo A R S; Aires-de-Sousa, João

    2014-01-01

    The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1)H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1)H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of

  15. The Effect of Detaching Bubbles on Aluminum-Cryolite Interfaces: An Experimental and Numerical Investigation

    Science.gov (United States)

    Einarsrud, Kristian Etienne

    2010-06-01

    Because of gas-induced flow in commercial aluminum reduction cells, deformations of the cryolite-aluminum interface will appear close to the side channel of the cell. In the present work, the dynamic nature of this phenomena is studied both in experiments and with help of a numerical model in the commercial computational fluid dynamics (CFD) code, FLUENT. Experiments are conducted in a full scale, two dimensional oil-water half-anode model, quantifying interfacial deformations over various operating conditions. Besides data on interfacial deformations, the experiments confirm previously published data on bubble motion under inclined anodes. The oil-water model is studied further with a three-fluid CFD model by means of a transient volume of fluid method. The model presented is verified and validated against experimentally measured data, yielding promising results. The CFD model is generalized further to realistic parameters for the Hall-Héroult cell. Averaged results from the transient model are compared with steady state calculations, showing good agreement. Average deformations up to 20 mm are observed under normal operating conditions. The transient approach shows that the dynamic behavior of the aluminum-cryolite interface is significant and is the same magnitude of the average deformations.

  16. Impact of the Solidification Rate on the Chemical Composition of Frozen Cryolite Bath

    Directory of Open Access Journals (Sweden)

    Sándor Poncsák

    2017-03-01

    Full Text Available Solidification of cryolite (Na3AlF6-based bath takes place at different rates along the sideledge, and around alumina rafts and new anodes. The solidification rate has a significant impact on the structure and the chemical composition that determine the thermal conductivity and thus the thickness of sideledge, or the duration of the existence of the temporary frozen bath layers in other cases. Unfortunately, samples that can be collected in industrial cells are formed under unknown, spatially and temporally varying conditions. For this reason, frozen bath samples were created under different heat flux conditions in a well-controlled laboratory environment using the so-called cold finger technique. The samples were analyzed by X-ray Diffractometer (XRD and Scanning Electron Microscope (SEM in Back Scattering (BS mode in order to obtain spatial distribution of chemical composition. Results were correlated with structural analysis. XRD confirmed our earlier hypothesis of recrystallization of cryolite to chiolite under medium heat flux regime. Lower α-alumina, and higher γ-alumina content in the samples obtained with very high heating rate suggest that fast cooling reduces α–γ conversion. In accordance with the expectation, SEM-BS revealed significant variation of the Na/Al ratio in the transient sample.

  17. Separation of Ethanol-Water MixtureUsing Type-A Zeolite Molecular Sieve

    Directory of Open Access Journals (Sweden)

    Juan Camilo Díaz

    2010-01-01

    Full Text Available This paper presents an experimental procedure for the synthesis of a type-A zeolite molecular sieve, usable in the separation of an ethanol-water mixture. The type-A zeolite molecular sieve is obtained from a reactive mixture formed by a source of alumina, a source of silica and a promoter. Characterization of the molecular sieves obtained in this work was undertaken using X-ray diffraction (XRD, adsorption isotherms and scanning electron microscopy (SEM. The results from the characterization procedures showed that part of the product presented a pore diameter suitable for the separation of an ethanol-water mixture.

  18. A pilot-scale study of cryolite precipitation from high fluoride-containing wastewater in a reaction-separation integrated reactor.

    Science.gov (United States)

    Jiang, Ke; Zhou, Kanggen; Yang, Youcai; Du, Hu

    2013-07-01

    Fluoride removal by traditional precipitation generates huge amounts of a water-rich sludge with low quality, which has no commercial or industrial value. The present study evaluated the feasibility of recovering fluoride as low water content cryolite from industrial fluoride-containing wastewater. A novel pilot-scale reaction-separation integrated reactor was designed. The results showed that the seed retention time in the reactor was prolonged to strengthen the induced crystallization process. The particle size of cryolite increased with increasing seed retention time, which decreased the water content. The recovery rate of cryolite was above 75% under an influent fluoride concentration of 3500 mg/L, a reaction temperature of 500C, and an influent flow of 40 L/hr. The cryolite products that precipitated from the reactor were small in volume, large in particle size, low in water content, high in crystal purity, and recyclable.

  19. Identifying contributors of DNA mixtures by means of quantitative information of STR typing

    DEFF Research Database (Denmark)

    Tvedebrink, Torben; Eriksen, Poul Svante; Mogensen, Helle Smidt

    2012-01-01

    identified using polymorphic genetic markers. However, modern typing techniques supply additional quantitative data, which contain very important information about the observed evidence. This is particularly true for cases of DNA mixtures, where more than one individual has contributed to the observed...... biological stain. This article presents a method for including the quantitative information of short tandem repeat (STR) DNA mixtures in the LR. Also, an efficient algorithmic method for finding the best matching combination of DNA mixture profiles is derived and implemented in an on-line tool for two......- and three-person DNA mixtures. Finally, we demonstrate for two-person mixtures how this best matching pair of profiles can be used in estimating the likelihood ratio using importance sampling. The reason for using importance sampling for estimating the likelihood ratio is the often vast number...

  20. Response of Cryolite-Based Bath to a Shift in Heat Input/output Balance

    Science.gov (United States)

    Liu, Jingjing; Taylor, Mark; Dorreen, Mark

    2017-04-01

    A technology for low amperage potline operation is now recognized as a competitive advantage for the aluminum smelting industry in order to align smelter operations with the power and aluminum price markets. This study investigates the cryolite-based bath response to heat balance shifts when the heat extraction from the bath is adjusted to different levels in a laboratory analogue. In the analogue experiments, the heat balance shift is driven by a graphite `cold finger' heat exchanger, which can control the heat extraction from the analogue, and a corresponding change in heat input from the furnace which maintains the control temperature of the lab "cell." This paper reports the first experimental results from shifting the steady state of the lab cell heat balance, and investigates the effects on the frozen ledge and bath superheat. The lab cell energy balances are compared with energy balances in a published industrial cell model.

  1. Response of Cryolite-Based Bath to a Shift in Heat Input/output Balance

    Science.gov (United States)

    Liu, Jingjing; Taylor, Mark; Dorreen, Mark

    2016-12-01

    A technology for low amperage potline operation is now recognized as a competitive advantage for the aluminum smelting industry in order to align smelter operations with the power and aluminum price markets. This study investigates the cryolite-based bath response to heat balance shifts when the heat extraction from the bath is adjusted to different levels in a laboratory analogue. In the analogue experiments, the heat balance shift is driven by a graphite `cold finger' heat exchanger, which can control the heat extraction from the analogue, and a corresponding change in heat input from the furnace which maintains the control temperature of the lab "cell." This paper reports the first experimental results from shifting the steady state of the lab cell heat balance, and investigates the effects on the frozen ledge and bath superheat. The lab cell energy balances are compared with energy balances in a published industrial cell model.

  2. Crystallization of -type hexagonal ferrites from mechanically activated mixtures of barium carbonate and goethite

    Indian Academy of Sciences (India)

    J Temuujin; M Aoyama; M Senna; T Masuko; C Ando; H Kishi; A Minjigmaa

    2006-10-01

    -type hexagonal ferrite precursor was prepared by a soft mechanochemical treatment of BaCO3 and -FeOOH mixtures. The effect of milling on its structure and thermal behaviour was examined by XRD, SEM and FTIR. Well crystallized -type hexagonal ferrite was formed from just 1 h milled precursors at 800°C. The beneficial effect of milling was explained in terms of increased homogeneity with simultaneous hetero bridging bond formation between powder constituents.

  3. Characteristic of Local Boiling Heat Transfer of Ammonia / Water Binary Mixture on the Plate Type Evaporator

    Science.gov (United States)

    Okamoto, Akio; Arima, Hirofumi; Kim, Jeong-Hun; Akiyama, Hirokuni; Ikegami, Yasuyuki; Monde, Masanori

    Ocean thermal energy conversion (OTEC) and discharged thermal energy conversion (DTEC) are expected to be the next generation energy production systems. Both systems use a plate type evaporator, and ammonia or ammonia/water mixture as a working fluid. It is important to clarify heat transfer characteristic for designing efficient power generation systems. Measurements of local boiling heat transfer coefficients and visualization were performed for ammonia /water mixture (z = 0.9) on a vertical flat plate heat exchanger in a range of mass flux (7.5 - 15 kg/m2s), heat flux (15 - 23 kW/m2), and pressure (0.7 - 0.9 MPa). The result shows that in the case of ammonia /water mixture, the local heat transfer coefficients increase with an increase of vapor quality and mass flux, and decrease with an increase of heat flux, and the influence of the flow pattern on the local heat transfer coefficient is observed.

  4. Dissolution kinetics for alumina in cryolite melts. Distribution of alumina in the electrolyte of industrial aluminium cells

    Energy Technology Data Exchange (ETDEWEB)

    Kobbeltvedt, Ove

    1997-12-31

    This thesis contributes to the understanding of which factors determine the rate of dissolution of alumina added to the bath in alumina reduction cells. Knowing this may help reduce the occurrences of operation interruptions and thus make it possible to produce aluminium using less energy. When alumina powder was added to a stirred cryolite melt, the alumina dissolved in two distinct main stages. In the first stage, the dissolution rate was very high, which reflects dissolution of single alumina grains that are being dispersed in the bath upon addition. In the second stage, lumps of alumina infiltrated with bath dissolved at a rate considerably slower than that of the first stage. The formation of these alumina agglomerates is the most important contributor to slow dissolution. The parameters varied in the experiments were convection, batch size, and temperature of the bath and of the added alumina. Increased gas stirring of the bath speeded up dissolution in both stages but the size of the batch was of little significance. Increasing the bath temperature had no effect in the first stage but speeded up dissolution considerably in the second stage. Compared to adding alumina at room temperature, preheating it to a high temperature (600 {sup o}C) increased the dissolution rate in the first stage while preheating to lower temperatures (100-300 {sup o}C) decreased the dissolution rate. In the second stage, preheating slowed the dissolution. The two latter phenomena of reduced dissolution rates are ascribed to the removal of moisture from the alumina upon preheating. The bath flow and the distribution of alumina in the bath were measured in four different types of cells. It was found that if a certain asymmetry of the magnetic field traverse to the cell was present, due to the presence of risers, then loops of high velocity bath flow occurred near the short ends of the cell. Thus, alumina added near the short ends is effectively transferred away from the feeding

  5. Anodic behaviour of oxidised Ni-Fe alloys in cryolite-alumina melts

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Vivien, E-mail: v.singleton@student.unsw.edu.a [Centre for Electrochemical and Mineral Processing, School of Chemical Engineering, University of New South Wales, Sydney 2052 (Australia); Welch, Barry J. [Welbank Consulting Ltd., PO Box 207, Whitianga 3542 (New Zealand); Skyllas-Kazacos, Maria [Centre for Electrochemical and Mineral Processing, School of Chemical Engineering, University of New South Wales, Sydney 2052 (Australia)

    2011-01-01

    Nickel-iron alloys have been identified as promising inert anode candidates for the Hall-Heroult process. In this study, binary Ni-Fe alloys of various compositions were subjected to short-term galvanostatic electrolysis in a cryolite-alumina bath at 960 {sup o}C. Prior to electrolysis, the anodes were oxidised at 800 {sup o}C for 48 h, forming a protective scale. Fe{sub 2}O{sub 3}, Ni{sub x}Fe{sub 3-x}O{sub 4} and Ni{sub x}Fe{sub 1-x}O were identified as the major scale components using a combination of X-ray diffraction (XRD) analysis and energy dispersive X-ray spectroscopy (EDX). Anodes having Ni content of 50-65 wt% performed adequately during short-term electrolysis, operating at a steady potential of 3-3.5 V vs. AlF{sub 3}/Al. Overall, it was found that the pre-formed oxide scale was effective in reducing anode wear and fluoridation. In the absence of a pre-formed scale, anodes were shown to undergo appreciable internal corrosion and/or passivation due to metal fluoride formation. Analysis of the anodes following electrolysis was performed using XRD and electron microprobe analysis (EPMA).

  6. Graphical evaluation of the ridge-type robust regression estimators in mixture experiments.

    Science.gov (United States)

    Erkoc, Ali; Emiroglu, Esra; Akay, Kadri Ulas

    2014-01-01

    In mixture experiments, estimation of the parameters is generally based on ordinary least squares (OLS). However, in the presence of multicollinearity and outliers, OLS can result in very poor estimates. In this case, effects due to the combined outlier-multicollinearity problem can be reduced to certain extent by using alternative approaches. One of these approaches is to use biased-robust regression techniques for the estimation of parameters. In this paper, we evaluate various ridge-type robust estimators in the cases where there are multicollinearity and outliers during the analysis of mixture experiments. Also, for selection of biasing parameter, we use fraction of design space plots for evaluating the effect of the ridge-type robust estimators with respect to the scaled mean squared error of prediction. The suggested graphical approach is illustrated on Hald cement data set.

  7. Graphical Evaluation of the Ridge-Type Robust Regression Estimators in Mixture Experiments

    Directory of Open Access Journals (Sweden)

    Ali Erkoc

    2014-01-01

    Full Text Available In mixture experiments, estimation of the parameters is generally based on ordinary least squares (OLS. However, in the presence of multicollinearity and outliers, OLS can result in very poor estimates. In this case, effects due to the combined outlier-multicollinearity problem can be reduced to certain extent by using alternative approaches. One of these approaches is to use biased-robust regression techniques for the estimation of parameters. In this paper, we evaluate various ridge-type robust estimators in the cases where there are multicollinearity and outliers during the analysis of mixture experiments. Also, for selection of biasing parameter, we use fraction of design space plots for evaluating the effect of the ridge-type robust estimators with respect to the scaled mean squared error of prediction. The suggested graphical approach is illustrated on Hald cement data set.

  8. Bayesian estimation of finite3-component mixture of Burr Type-XII distributions assuming Type-I right censoring scheme

    Directory of Open Access Journals (Sweden)

    M. Tahir

    2016-12-01

    Full Text Available As compared to simple models, the mixture models of underlying lifetime distributions are intuitively more appropriate and appealing to model the heterogeneous nature of process. This study focuses on the problem of estimating the parameters of a newly developed 3-component mixture of Burr Type-XII distributions using Type-I right censored data. Firstly, considering a Bayesian structure, some mathematical properties of a 3-component mixture of Burr Type-XII distributions are discussed. These mathematical properties include Bayes estimators and posterior risks for the unknown component and proportion parameters using the non-informative and the informative priors under squared error loss function, precautionary loss function and DeGroot loss function. Secondly, in case when no or little prior information is available, elicitation of hyperparameters is given. Also, the posterior predictive distribution for a future observation and the Bayesian predictive interval are constructed. Moreover, the limiting expressions for the Bayes estimators and posterior risks are derived. In addition, the performance of the Bayes estimators for different sample sizes, test termination times and parametric values under different loss functions is investigated. Finally, simulated datasets are designed for the different comparisons and the model is illustrated using the real data.

  9. A new strategy for sperm isolation and STR typing from multi-donor sperm mixtures.

    Science.gov (United States)

    Han, Jun-Ping; Yang, Fan; Xu, Cheng; Wei, Yi-Liang; Zhao, Xing-Chun; Hu, Lan; Ye, Jian; Li, Cai-Xia

    2014-11-01

    Mixed semen stains from multiple contributors are challenging samples in sexual assault casework, and it is crucial to obtain the DNA profiles of different donors to allow the evidence to play an important role in investigations and judicial proceedings. Current standard procedures, including preferential lysis, are incapable of separating single-source sperm from multiple male donors. Mixed profiles are often obtained and may not directly exclude or identify suspects. In this case, computational methods for mixture interpretation are often used, which rely on different types of calculation models. Here, we explored a new strategy for sperm cell isolation and detection from mixtures. It is a direct way to obtain genotypes of different sperm donors compared to computation-based mixture interpretation. Laser capture microdissection (LCM) and low volume-PCR (LV-PCR) were used for single sperm isolation and detection. The platform was sensitive; profiling of a single sperm cell generated a minimum of 13-16 loci in 73.1% of Y short tandem repeat (Y-STR) assays. A new Y-STR and autosomal STR multiplex system (YA-STR) were optimized by the combination of the Y-STR locus and 10 autosomal STR (auto STR) loci. The Y-STR locus acted as a tag to discriminate profile groups from different donors. Subsequently, consensus auto STR profiles of various persons could be received. The accuracy and availability of this method were evaluated on a three-donor semen mixture and found to be effective for the resolution of a multi-donor sperm mixture.

  10. Modelling shallow debris flows of the Coulomb-mixture type over temporally varying topography

    Directory of Open Access Journals (Sweden)

    Y. C. Tai

    2012-02-01

    Full Text Available We propose a saturated binary mixture model for debris flows of the Coulomb-mixture type over temporally varying topography, where the effects of erosion and deposition are considered. Due to the deposition or erosion processes, the interface between the moving material and the stagnant base is a non-material singular surface. The motion of this singular surface is determined by the mass exchange between the flowing layer and the ground. The ratio of the relative velocity between the two constituents to the velocity of the solid phase is assumed to be small, so that the governing equations can be reduced to a system of the quasi-single-phase type. A shock-capturing numerical scheme is implemented to solve the derived equation system. The deposition shapes of a finite mass sliding down an inclined planary chute are investigated for a range of mixture ratios. The geometric evolution of the deposition is presented, which allows the possibility of mimicking the development of levee deposition.

  11. Preparation of Al-Si-Ti Master Alloys by Electrolysis of Silica and Titania in Cryolite-Alumina Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Aluminum-silicon-titanium master alloys were prepared in the laboratory by electrolysis of silica and titania dissolved in cryolite-alumina melts. Alloys containing up to 12 mass% Si and 2.6 mass% Ti were formed after about 90 min of electrolysis at 950℃. The current efficiency for the preparation of the Al-Si-Ti alloys varied with time, temperature and cathodic current density. It is concluded that this electrolytic method may be an interesting alternative to the direct metal mixing process for formation of Al-Si-Ti master alloys.

  12. CONSOLIDATION AND COMPACTION OF POWDER MIXTURES .1. BINARY-MIXTURES OF SAME PARTICLE-SIZE FRACTIONS OF DIFFERENT TYPES OF CRYSTALLINE LACTOSE

    NARCIS (Netherlands)

    RIEPMA, KA; LERK, CF; DEBOER, AH; BOLHUIS, GK; KUSSENDRAGER, KD

    1990-01-01

    Binary powder mixtures of four different types of crystalline lactose: alpha-lactose monohydrate, anhydrous alpha-lactose, roller-dried beta-lactose and crystalline beta-lactose, were compressed into tablets. The results showed a proportional intercorrelation of the crushing strength and internal sp

  13. On the structure of crystalline and molten cryolite: Insights from the ab initio molecular dynamics in NpT ensemble

    Science.gov (United States)

    Bučko, Tomáš; Šimko, František

    2016-02-01

    Ab initio molecular dynamics simulations in isobaric-isothermal ensemble have been performed to study the low- and the high-temperature crystalline and liquid phases of cryolite. The temperature induced transitions from the low-temperature solid (α) to the high-temperature solid phase (β) and from the phase β to the liquid phase have been simulated using a series of MD runs performed at gradually increasing temperature. The structure of crystalline and liquid phases is analysed in detail and our computational approach is shown to reliably reproduce the available experimental data for a wide range of temperatures. Relatively frequent reorientations of the AlF6 octahedra observed in our simulation of the phase β explain the thermal disorder in positions of the F- ions observed in X-ray diffraction experiments. The isolated AlF63-, AlF52-, AlF4-, as well as the bridged Al 2 Fm 6 - m ionic entities have been identified as the main constituents of cryolite melt. In accord with the previous high-temperature NMR and Raman spectroscopic experiments, the compound AlF5 2 - has been shown to be the most abundant Al-containing species formed in the melt. The characteristic vibrational frequencies for the AlFn 3 - n species in realistic environment have been determined and the computed values have been found to be in a good agreement with experiment.

  14. Preparation and Characteristics of Polyaluminium Chloride by Utilizing Fluorine-Containing Waste Acidic Mother Liquid from Clay-Brine Synthetic Cryolite Process

    Directory of Open Access Journals (Sweden)

    Feng-shan Zhou

    2014-01-01

    Full Text Available Clay-brine process employing activated clay, NaCl, HCl, and HF as raw materials is the primarily advanced technology to synthesize cryolite in the present industrial grade. However, plenty of byproducts of fluorine-containing waste HCl at the concentration of about 10%~12% could not be utilized comprehensively and are even hazardous to the environment. This work proposed a new two-step technology to prepare inorganic polymer flocculants polyaluminium chloride (PAC from synthetic cryolite mother liquor. Many specific factors such as the variety of aluminide source, reaction temperature and time, reagent ratio, and manner of alkaline addition were taken into consideration and their influences on the performances of produced PAC were discussed. It was found that synthetic cryolite mother liquor could react with bauxite and calcium aluminate directly to prepare cheap PAC, with plenty amount of water insoluble CaF2 and CaSiF6 produced as well. However, once HCl was introduced into synthetic cryolite mother liquor as well as by utilizing bauxite as aluminide source and sodium aluminate as adjusting basicity agent, the resultant PAC would dissolve out higher amount of aluminum while producing little amount of water insoluble materials. The coagulation behavior of the specially produced PAC could even match the industrial grade PAC conforming to national standard.

  15. Efficacy and Safety of a Mixture of Two Different Brands of Insulin Products in Patients with Type 1 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Jeng-Bin Chiou

    2005-11-01

    Conclusion: This retrospective study demonstrated that using a mixture of different brands of insulin (Insulatard HM plus Humulin R for 6 months did not change the efficacy of insulin in patients with type 1 diabetes mellitus.

  16. Detection of gene expression in an individual cell type within a cell mixture using microarray analysis.

    Directory of Open Access Journals (Sweden)

    Penelope A Bryant

    Full Text Available BACKGROUND: A central issue in the design of microarray-based analysis of global gene expression is the choice between using cells of single type and a mixture of cells. This study quantified the proportion of lipopolysaccharide (LPS induced differentially expressed monocyte genes that could be measured in peripheral blood mononuclear cells (PBMC, and determined the extent to which gene expression in the non-monocyte cell fraction diluted or obscured fold changes that could be detected in the cell mixture. METHODOLOGY/PRINCIPAL FINDINGS: Human PBMC were stimulated with LPS, and monocytes were then isolated by positive (Mono+ or negative (Mono- selection. The non-monocyte cell fraction (MonoD remaining after positive selection of monocytes was used to determine the effect of non-monocyte cells on overall expression. RNA from LPS-stimulated PBMC, Mono+, Mono- and MonoD samples was co-hybridised with unstimulated RNA for each cell type on oligonucleotide microarrays. There was a positive correlation in gene expression between PBMC and both Mono+ (0.77 and Mono- (0.61-0.67 samples. Analysis of individual genes that were differentially expressed in Mono+ and Mono- samples showed that the ability to detect expression of some genes was similar when analysing PBMC, but for others, differential expression was either not detected or changed in the opposite direction. As a result of the dilutional or obscuring effect of gene expression in non-monocyte cells, overall about half of the statistically significant LPS-induced changes in gene expression in monocytes were not detected in PBMC. However, 97% of genes with a four fold or greater change in expression in monocytes after LPS stimulation, and almost all (96-100% of the top 100 most differentially expressed monocyte genes were detected in PBMC. CONCLUSIONS/SIGNIFICANCE: The effect of non-responding cells in a mixture dilutes or obscures the detection of subtle changes in gene expression in an individual

  17. Separating mixtures of aerosol types in airborne High Spectral Resolution Lidar data

    Science.gov (United States)

    Burton, S. P.; Vaughan, M. A.; Ferrare, R. A.; Hostetler, C. A.

    2014-02-01

    Knowledge of aerosol type is important for determining the magnitude and assessing the consequences of aerosol radiative forcing, and can provide useful information for source attribution studies. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. This paper extends the work of earlier researchers by using the aerosol intensive parameters measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) to develop a comprehensive and unified set of rules for characterizing the external mixing of several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e., lidar ratio), backscatter color ratio, and depolarization ratio. We present the mixing rules in a particularly simple form that leads easily to mixing rules for the covariance matrices that describe aerosol distributions, rather than just single values of measured parameters. These rules can be applied to infer mixing ratios from the lidar-observed aerosol parameters, even for cases without significant depolarization. We demonstrate our technique with measurement curtains from three HSRL-1 flights which exhibit mixing between two aerosol types, urban pollution plus dust, marine plus dust, and smoke plus marine. For these cases, we infer a time-height cross-section of extinction mixing ratio along the flight track, and partition aerosol extinction into portions attributed to the two pure types.

  18. Separating mixtures of aerosol types in airborne High Spectral Resolution Lidar data

    Directory of Open Access Journals (Sweden)

    S. P. Burton

    2013-09-01

    Full Text Available Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. This paper extends the work of earlier researchers by using the aerosol intensive parameters measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1 to develop a comprehensive and unified set of rules for characterizing the external mixing of several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio, backscatter color ratio, and depolarization ratio. We present the mixing rules in a particularly simple form that leads easily to mixing rules for the covariance matrices that describe aerosol distributions, rather than just scalar values of measured parameters. These rules can be applied to infer mixing ratios from the lidar-observed aerosol parameters, even for cases without significant depolarization. We demonstrate our technique with measurement curtains from three HSRL-1 flights which exhibit mixing between two aerosol types, urban pollution plus dust, marine plus dust, and smoke plus marine. For these cases, we infer a time-height cross-section of mixing ratio along the flight track, and partition aerosol extinction into portions attributed to the two pure types.

  19. Plasma Kinetics in the Ethanol/Water/Air Mixture in "Tornado" Type Electrical Discharge

    CERN Document Server

    Levko, D; Chernyak, V; Olszewski, S; Nedybaliuk, O

    2011-01-01

    This paper presents the results of a theoretical and experimental study of plasma-assisted reforming of ethanol into molecular hydrogen in a new modification of the "tornado" type electrical discharge. Numerical modeling clarifies the nature of the non-thermal conversion and explains the kinetic mechanism of nonequilibrium plasma-chemical transformations in the gas-liquid system and the evolution of hydrogen during the reforming as a function of discharge parameters and ethanol-to-water ratio in the mixture. We also propose a scheme of chemical reactions for plasma kinetics description. It is shown that some characteristics of the investigated reactor are at least not inferior to characteristics of other plasma chemical reactors.

  20. Numerical Modeling of Flow Dynamics in The Aluminum Smelting Process: Comparison Between Air-Water and CO2-Cryolite Systems

    Science.gov (United States)

    Zhao, Zhibin; Feng, Yuqing; Schwarz, M. Philip; Witt, Peter J.; Wang, Zhaowen; Cooksey, Mark

    2017-04-01

    Air-water models have been widely applied as substitutes for CO2-cryolite systems in the study of the complex bubble dynamics and bubble-driven flow that occurs in the molten electrolyte phase in the aluminum electrolytic process, but the detailed difference between the two systems has not been studied. This paper makes a numerical comparison between the bubble dynamics for the two systems. Simulations of both single bubble and continuous bubbling were conducted using a three-dimensional computational fluid dynamics (3D CFD) modeling approach with a volume of fluid (VOF) method to capture the phase interfaces. In the single bubble simulations, it was found that bubbles sliding under an anode in a CO2-cryolite system have a smaller bubble thickness and a higher sliding velocity than those in the air-water system for bubbles of the same volume. Dimensionless analysis and numerical simulation show that contact angle is the dominant factor producing these differences; the effects of kinematic viscosity, surface tension, and density are very small. In the continuous bubbling simulations, the continuous stream of air bubbles detaches from the anode sidewall after a period of climbing, just as it does in the single bubble simulation, but bubbles have less tendency to migrate away from the wall. Quasi-stable state flow characteristics, i.e., time-averaged bath flow pattern, turbulence kinetic energy, turbulence dissipation rate, and gas volume fraction, show a remarkable agreement between the two systems in terms of distribution and magnitude. From the current numerical comparisons, it is believed that the air-water model is a close substitutive model for studying bubble-driven bath flow in aluminum smelting processes. However, because of the difference in bubble morphologies between the two systems, and also the reactive generation and growth of bubbles in the real system, there will likely be some differences in bubble coverage of the anode in the anode-cathode gap.

  1. Numerical Modeling of Flow Dynamics in The Aluminum Smelting Process: Comparison Between Air-Water and CO2-Cryolite Systems

    Science.gov (United States)

    Zhao, Zhibin; Feng, Yuqing; Schwarz, M. Philip; Witt, Peter J.; Wang, Zhaowen; Cooksey, Mark

    2016-12-01

    Air-water models have been widely applied as substitutes for CO2-cryolite systems in the study of the complex bubble dynamics and bubble-driven flow that occurs in the molten electrolyte phase in the aluminum electrolytic process, but the detailed difference between the two systems has not been studied. This paper makes a numerical comparison between the bubble dynamics for the two systems. Simulations of both single bubble and continuous bubbling were conducted using a three-dimensional computational fluid dynamics (3D CFD) modeling approach with a volume of fluid (VOF) method to capture the phase interfaces. In the single bubble simulations, it was found that bubbles sliding under an anode in a CO2-cryolite system have a smaller bubble thickness and a higher sliding velocity than those in the air-water system for bubbles of the same volume. Dimensionless analysis and numerical simulation show that contact angle is the dominant factor producing these differences; the effects of kinematic viscosity, surface tension, and density are very small. In the continuous bubbling simulations, the continuous stream of air bubbles detaches from the anode sidewall after a period of climbing, just as it does in the single bubble simulation, but bubbles have less tendency to migrate away from the wall. Quasi-stable state flow characteristics, i.e., time-averaged bath flow pattern, turbulence kinetic energy, turbulence dissipation rate, and gas volume fraction, show a remarkable agreement between the two systems in terms of distribution and magnitude. From the current numerical comparisons, it is believed that the air-water model is a close substitutive model for studying bubble-driven bath flow in aluminum smelting processes. However, because of the difference in bubble morphologies between the two systems, and also the reactive generation and growth of bubbles in the real system, there will likely be some differences in bubble coverage of the anode in the anode-cathode gap.

  2. An analysis of lethal and sublethal interactions among type I and type II pyrethroid pesticide mixtures using standard Hyalella azteca water column toxicity tests.

    Science.gov (United States)

    Hoffmann, Krista Callinan; Deanovic, Linda; Werner, Inge; Stillway, Marie; Fong, Stephanie; Teh, Swee

    2016-10-01

    A novel 2-tiered analytical approach was used to characterize and quantify interactions between type I and type II pyrethroids in Hyalella azteca using standardized water column toxicity tests. Bifenthrin, permethrin, cyfluthrin, and lambda-cyhalothrin were tested in all possible binary combinations across 6 experiments. All mixtures were analyzed for 4-d lethality, and 2 of the 6 mixtures (permethrin-bifenthrin and permethrin-cyfluthrin) were tested for subchronic 10-d lethality and sublethal effects on swimming motility and growth. Mixtures were initially analyzed for interactions using regression analyses, and subsequently compared with the additive models of concentration addition and independent action to further characterize mixture responses. Negative interactions (antagonistic) were significant in 2 of the 6 mixtures tested, including cyfluthrin-bifenthrin and cyfluthrin-permethrin, but only on the acute 4-d lethality endpoint. In both cases mixture responses fell between the additive models of concentration addition and independent action. All other mixtures were additive across 4-d lethality, and bifenthrin-permethrin and cyfluthrin-permethrin were also additive in terms of subchronic 10-d lethality and sublethal responses. Environ Toxicol Chem 2016;35:2542-2549. © 2016 SETAC.

  3. Photo-spectroscopy of mixtures of catalyst particles reveals their age and type

    NARCIS (Netherlands)

    Kerssens, M M; Wilbers, A; Kramer, J; de Peinder, P; Mesu, G; Nelissen, B J; Vogt, E T C; Weckhuysen, B M

    2016-01-01

    Within a fluid catalytic cracking (FCC) unit, a mixture of catalyst particles that consist of either zeolite Y (FCC-Y) or ZSM-5 (FCC-ZSM-5) is used in order to boost the propylene yield when processing crude oil fractions. Mixtures of differently aged FCC-Y and FCC-ZSM-5 particles circulating in the

  4. Growth of n-type ZnO thin films by using mixture gas of hydrogen and argon

    Institute of Scientific and Technical Information of China (English)

    Zhou Xin; Wang Shi-Qi; Lian Gui-Jun; Xiong Guang-Cheng

    2006-01-01

    High-quality oxide semiconductor ZnO thin films were prepared on single-crystal sapphire and LaAlO3 substrates by pulsed laser deposition (PLD) in the mixture gas of hydrogen and argon. Low resistivity n-type ZnO thin films with smoother surface were achieved by deposition at 600℃ in 1Pa of the mixture gas. In addition, ferromagnetism was observed in Co-doped ZnO thin films and rectification Ⅰ-Ⅴ curves were found in p-GaN/n-ZnO and p-CdTe/n-ZnO heterostructure junctions. The results indicated that using mixture gas of hydrogen and argon in PLD technique was a flexible method for depositing high-quality n-type oxide semiconductor films, especially for the multilayer thin film devices.

  5. Effect of noble gas mixtures on the performance of regenerative-type cryocoolers analytical estimate

    Science.gov (United States)

    Daney, D. E.

    1990-09-01

    The performance of regenerators that use noble gas mixtures is compared to the performance of those that use pure helium gas. Both helium-argon and helium-krypton mixtures are investigated. For some heat transfer surfaces, a modest gain in heat transfer can be achieved with these mixtures. The concomitant increase in pressure drop, however, more than offsets the heat transfer gain so the net regenerator loss increases for all evaluated cases. The dependence of heat transfer on Prandtl number (Pr) was not measured for the range associated with noble gas mixtures, 0.2 less than Pr less than 0.5, and it is estimated that the uncertainty from the source can exceed 20 percent. The estimates for the transport properties (Prandtl number, viscosity, and thermal conductivity) of helium-argon and helium-krypton mixtures because of the absence of experimental data at low temperature are given.

  6. Certain Equilibrium Properties of Gases and Gas Mixtures an Steeper lennard-Jones and Stockmayer Type Potentials

    Directory of Open Access Journals (Sweden)

    S. C. Saxena

    1967-04-01

    Full Text Available The discussion on second virial and zero pressure Joule-Thomson coefficients of non polar gases and gas mixtures is given on the Lennard Jones Type Potentials with the choice of the repulsive index as 12 and 18. These studies are also extended to polar gases and gas mixtures by including the electric dipole-dipole moment term in the two potentials. The tabulations are given for the (18-6-3 potential to enable computations of second virial and Joule-Thomson coefficients.

  7. Algorithms and programs of dynamic mixture estimation unified approach to different types of components

    CERN Document Server

    Nagy, Ivan

    2017-01-01

    This book provides a general theoretical background for constructing the recursive Bayesian estimation algorithms for mixture models. It collects the recursive algorithms for estimating dynamic mixtures of various distributions and brings them in the unified form, providing a scheme for constructing the estimation algorithm for a mixture of components modeled by distributions with reproducible statistics. It offers the recursive estimation of dynamic mixtures, which are free of iterative processes and close to analytical solutions as much as possible. In addition, these methods can be used online and simultaneously perform learning, which improves their efficiency during estimation. The book includes detailed program codes for solving the presented theoretical tasks. Codes are implemented in the open source platform for engineering computations. The program codes given serve to illustrate the theory and demonstrate the work of the included algorithms.

  8. New insights into mycotoxin mixtures: The toxicity of low doses of Type B trichothecenes on intestinal epithelial cells is synergistic

    Energy Technology Data Exchange (ETDEWEB)

    Alassane-Kpembi, Imourana [INRA, UMR 1331 Toxalim, Research Center in Food Toxicology, F-31027 Toulouse (France); Université de Toulouse, ENVT, INP, UMR 1331 Toxalim, F-31076 Toulouse (France); Institut des Sciences Biomédicales Appliquées, Cotonou, Bénin (Benin); Kolf-Clauw, Martine; Gauthier, Thierry; Abrami, Roberta [INRA, UMR 1331 Toxalim, Research Center in Food Toxicology, F-31027 Toulouse (France); Université de Toulouse, ENVT, INP, UMR 1331 Toxalim, F-31076 Toulouse (France); Abiola, François A. [Institut des Sciences Biomédicales Appliquées, Cotonou, Bénin (Benin); Oswald, Isabelle P., E-mail: Isabelle.Oswald@toulouse.inra.fr [INRA, UMR 1331 Toxalim, Research Center in Food Toxicology, F-31027 Toulouse (France); Université de Toulouse, ENVT, INP, UMR 1331 Toxalim, F-31076 Toulouse (France); Puel, Olivier [INRA, UMR 1331 Toxalim, Research Center in Food Toxicology, F-31027 Toulouse (France); Université de Toulouse, ENVT, INP, UMR 1331 Toxalim, F-31076 Toulouse (France)

    2013-10-01

    Deoxynivalenol (DON) is the most prevalent trichothecene mycotoxin in crops in Europe and North America. DON is often present with other type B trichothecenes such as 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), nivalenol (NIV) and fusarenon-X (FX). Although the cytotoxicity of individual mycotoxins has been widely studied, data on the toxicity of mycotoxin mixtures are limited. The aim of this study was to assess interactions caused by co-exposure to Type B trichothecenes on intestinal epithelial cells. Proliferating Caco-2 cells were exposed to increasing doses of Type B trichothecenes, alone or in binary or ternary mixtures. The MTT test and neutral red uptake, respectively linked to mitochondrial and lysosomal functions, were used to measure intestinal epithelial cytotoxicity. The five tested mycotoxins had a dose-dependent effect on proliferating enterocytes and could be classified in increasing order of toxicity: 3-ADON < 15-ADON ≈ DON < NIV ≪ FX. Binary or ternary mixtures also showed a dose-dependent effect. At low concentrations (cytotoxic effect between 10 and 30–40%), mycotoxin combinations were synergistic; however DON–NIV–FX mixture showed antagonism. At higher concentrations (cytotoxic effect around 50%), the combinations had an additive or nearly additive effect. These results indicate that the simultaneous presence of low doses of mycotoxins in food commodities and diet may be more toxic than predicted from the mycotoxins alone. Considering the frequent co-occurrence of trichothecenes in the diet and the concentrations of toxins to which consumers are exposed, this synergy should be taken into account. - Highlights: • We assessed the individual and combined cytotoxicity of five trichothecenes. • The tested concentrations correspond to the French consumer exposure levels. • The type of interaction in combined cytotoxicity varied with the effect level. • Low doses of Type B trichothecenes induced synergistic

  9. Efficiency of additives of the polysaccharide type on physical properties of bentonite mixtures

    Directory of Open Access Journals (Sweden)

    J. Beňo

    2011-01-01

    Full Text Available The addition of polysaccharide additives generally aims at improving some important physical properties of bentonite mixt ures, above allthe stability of moulds against the water loss and prevention of surface defects of castings. Polysaccharide products of inland and foreign production were checked in mixtures of two bentonites of the Czech provenance with the same montmorillonite content. The attention was paid in particular to the abrasion resistance of mixtures during storing them under constant climatic conditions.Conclusions have shownthe substantial influence of: the amount of the added additive, the kind and structural composition of the additive (pH of the water extract, electric conductance.

  10. Asphalt Mixture Fatigue Testing: Influence of Test Type and Specimen Size

    NARCIS (Netherlands)

    Li, N.

    2013-01-01

    Fatigue characterization of an asphalt mixture is commonly estimated by laboratory fatigue tests. Based on the classical fatigue analysis, fatigue lives obtained from different test devices are not comparable even when they are performed at the same test conditions. It is believed that there are

  11. Asphalt Mixture Fatigue Testing: Influence of Test Type and Specimen Size

    NARCIS (Netherlands)

    Li, N.

    2013-01-01

    Fatigue characterization of an asphalt mixture is commonly estimated by laboratory fatigue tests. Based on the classical fatigue analysis, fatigue lives obtained from different test devices are not comparable even when they are performed at the same test conditions. It is believed that there are tw

  12. New insights into mycotoxin mixtures: the toxicity of low doses of Type B trichothecenes on intestinal epithelial cells is synergistic.

    Science.gov (United States)

    Alassane-Kpembi, Imourana; Kolf-Clauw, Martine; Gauthier, Thierry; Abrami, Roberta; Abiola, François A; Oswald, Isabelle P; Puel, Olivier

    2013-10-01

    Deoxynivalenol (DON) is the most prevalent trichothecene mycotoxin in crops in Europe and North America. DON is often present with other type B trichothecenes such as 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), nivalenol (NIV) and fusarenon-X (FX). Although the cytotoxicity of individual mycotoxins has been widely studied, data on the toxicity of mycotoxin mixtures are limited. The aim of this study was to assess interactions caused by co-exposure to Type B trichothecenes on intestinal epithelial cells. Proliferating Caco-2 cells were exposed to increasing doses of Type B trichothecenes, alone or in binary or ternary mixtures. The MTT test and neutral red uptake, respectively linked to mitochondrial and lysosomal functions, were used to measure intestinal epithelial cytotoxicity. The five tested mycotoxins had a dose-dependent effect on proliferating enterocytes and could be classified in increasing order of toxicity: 3-ADONmycotoxin combinations were synergistic; however DON-NIV-FX mixture showed antagonism. At higher concentrations (cytotoxic effect around 50%), the combinations had an additive or nearly additive effect. These results indicate that the simultaneous presence of low doses of mycotoxins in food commodities and diet may be more toxic than predicted from the mycotoxins alone. Considering the frequent co-occurrence of trichothecenes in the diet and the concentrations of toxins to which consumers are exposed, this synergy should be taken into account.

  13. Effect of new type of synthetic waxes on reduced production and compaction temperature of asphalt mixture with reclaimed asphalt

    Science.gov (United States)

    Valentová, Tereza; Benešová, Lucie; Mastný, Jan; Valentin, Jan

    2017-09-01

    Lower mixing and paving temperatures of asphalt mixtures, which are an important issue in recent years, with respect to increased energy demand of civil engineering structures during their processing, allow reduction of this demand and result in minimized greenhouse gas production. In present time, there are many possibilities how to achieve reduction of production temperature during the mixing and paving of an asphalt mixture. The existing solutions distinguish in target operating temperature behaviour which has to be achieved in terms of good workability. This paper is focused on technical solutions based on use of new types of selected synthetic and bio-based waxes. In case of bio-based additive sugar cane wax was used, which is free of paraffins and is reclaimed as waste product during processing of sugar cane. The used waxes are added to bituminous binder in form of free-flowing granules or fine-grained powder. Synthetic waxes are represented by new series of Fischer-Tropsch wax in form of fine granules as well as by polyethylene waxes in form of fine-grained powder or granules. Those waxes were used to modify a standard paving grade bitumen dosed into asphalt mixture of ACsurf type containing up to 30 % of reclaimed asphalt (RA).

  14. Photo-spectroscopy of mixtures of catalyst particles reveals their age and type.

    Science.gov (United States)

    Kerssens, M M; Wilbers, A; Kramer, J; de Peinder, P; Mesu, G; Nelissen, B J; Vogt, E T C; Weckhuysen, B M

    2016-07-01

    Within a fluid catalytic cracking (FCC) unit, a mixture of catalyst particles that consist of either zeolite Y (FCC-Y) or ZSM-5 (FCC-ZSM-5) is used in order to boost the propylene yield when processing crude oil fractions. Mixtures of differently aged FCC-Y and FCC-ZSM-5 particles circulating in the FCC unit, the so-called equilibrium catalyst (Ecat), are routinely studied to monitor the overall efficiency of the FCC process. In this study, the age of individual catalyst particles is evaluated based upon photographs after selective staining with substituted styrene molecules. The observed color changes are linked to physical properties, such as the micropore volume and catalytic cracking activity data. Furthermore, it has been possible to determine the relative amount of FCC-Y and FCC-ZSM-5 in an artificial series of physical mixtures as well as in an Ecat sample with unknown composition. As a result, a new practical tool is introduced in the field of zeolite catalysis to evaluate FCC catalyst performances on the basis of photo-spectroscopic measurements with an off-the-shelf digital single lens reflex (DSLR) photo-camera with a macro lens. The results also demonstrate that there is an interesting time and cost trade-off between single catalyst particle studies, as performed with e.g. UV-vis, synchrotron-based IR and fluorescence micro-spectroscopy, and many catalyst particle photo-spectroscopy studies, making use of a relatively simple DSLR photo-camera. The latter approach offers clear prospects for the quality control of e.g. FCC catalyst manufacturing plants.

  15. Determination of nitroaromatic and nitramine type energetic materials in synthetic and real mixtures by cyclic voltammetry.

    Science.gov (United States)

    Üzer, Ayşem; Sağlam, Sener; Tekdemir, Yasemin; Ustamehmetoğlu, Belkıs; Sezer, Esma; Erçağ, Erol; Apak, Reşat

    2013-10-15

    Nitro-explosives contain reducible aromatic -NO2 groups or cyclic >N-NO2 bonds that may undergo reductive cleavage. This work reports the development of a cyclic voltammetric (CV) assay for nitro-aromatics (trinitrotoluene (TNT), dinitrotoluene (DNT)) and nitramines (1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)) using a glassy carbon electrode. This determination was first used for these energetic materials by resolving current responses of reduction potentials primarily due to one constituent but partly contributed by other constituents. Calibration curves of current intensity versus concentration were linear in the range of 30-120 mg L(-1) for RDX with a limit of detection (LOD) of 10.2 mg L(-1), 40-120 mg L(-1) for HMX (LOD=11.7 mg L(-1)), 40-120 mg L(-1) for TNT (LOD=11.2 mg L(-1)), and 40-140 mg L(-1) for DNT (LOD=10.8 mg L(-1)). Results showed that the CV method could provide a sensitive approach for the simultaneous determination of RDX and TNT in synthetic and real mixtures. Deconvolution of current contributions of mixtures at peak potentials of constituents was performed by multiple linear regression. The proposed method was successfully applied to the analysis of military explosives comp A5 and octol, and method validation was performed both against HPLC on a comp B (TNT+RDX) sample and against GC-MS on real post-blast residual samples containing both explosives.

  16. 低钾含量低温电解质中阴极电解膨胀研究%Cathode expansion of low potassium-sodium cryolite

    Institute of Scientific and Technical Information of China (English)

    马绍良; 李劼; 田忠良; 李胜银; 吕晓军; 赖延清; 刘业翔

    2012-01-01

    Semi-graphitic cathode electrolytic measuring swelling was studied based on sodium-potassium cryolite mixed system, the results show that as the content of A1F3 increases, the cathode electrolysis swelling gradually decreases, and as the content of AIF3 increases, semi-graphitic cathode on the impact of inflation is also exacerbated. Semi-graphitic cathode expansion rate increases with the increase of potassium, and the semi-graphitic cathode expansion rate first increases and then decreases with the increase of the content of potassium cryolite.%以钠冰晶石-钾冰晶石混合体系作为研究对象,测量半石墨质阴极电解膨胀率.研究结果表明:随着AlF3含量的增加,阴极电解膨胀率逐渐降低,且随着AlF3含量的增加,对半石墨质阴极膨胀的影响也加剧了.随着钾含量的增加,半石墨质阴极膨胀率增大,随着钾冰晶石含量的增加,对半石墨质阴极膨胀率的影响是先加剧后减弱.

  17. Low Temperature Properties Of Fuel Mixtures Of Kerosene And Fame Type Used To Supply Turbine Engines In Marine And Other Non-Aeronautical Applications

    National Research Council Canada - National Science Library

    Wojciech Dzięgielewski; Bartosz Gawron; Andrzej Kulczycki

    2015-01-01

    .... Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics...

  18. M2KMIX: Identifying the Type of High Rate Flooding Attacks using a Mixture of Expert Systems

    Directory of Open Access Journals (Sweden)

    Arun Raj Kumar P.

    2012-02-01

    Full Text Available High rate flooding attacks such as SYN flood, UDP flood, and HTTP flood have been posing a perilous threat to Web servers, DNS servers, Mail servers, VoIP servers, etc. These high rate flooding attacks deplete the limited capacity of the server resources. Hence, there is a need for the protection of these critical resources from high rate flooding attacks. Existing detection techniques used in Firewalls, IPS, IDS, etc., fail to identify the illegitimate traffic due to its self-similarity nature of legitimate traffic and suffer from low detection accuracy and high false alarms. Also, very few in the literature have focused on identifying the type of attack. This paper focuses on the identification of type of high rate flooding attack with High detection accuracy and fewer false alarms. The attack type identification is achieved by training the classifiers with different feature subsets. Therefore, each trained classifier is an expert in different feature space. High detection accuracy is achieved by creating a mixture of expert classifiers and the ensemble output decisions are identified by our proposed Preferential Agreement (PA rule. Our proposed classification algorithm, M2KMix (mixture of two Multi Layer Perceptron and one K-Nearest Neighbor models differs from the existing solutions in feature selection, error cost reduction, and attack type identification. M2KMix was trained and tested with our own SSE Lab 2011 dataset and CAIDA dataset. Detection accuracy and False Alarms are the two metrics used to analyze the performance of the proposed M2KMix algorithm with the existing output combination methods such as mean, maximum, minimum, and product. From the simulation results, it is evident that M2KMix algorithm achieves high detection accuracy (97.8% with fewer false alarms than the existing output combination methods. M2KMix identifies three types of flooding attacks, viz., the SYN Flood, UDP flood, and HTTP Flood, effectively with detection

  19. Solubility parameter of drugs for predicting the solubility profile type within a wide polarity range in solvent mixtures.

    Science.gov (United States)

    Peña, M A; Reíllo, A; Escalera, B; Bustamante, P

    2006-09-14

    The solubility enhancement produced by two binary mixtures with a common cosolvent (ethanol-water and ethyl acetate-ethanol) was studied against the solubility parameter of the mixtures (delta1) to characterize different types of solubility profiles. Benzocaine, salicylic acid and acetanilide show a single peak in the least polar mixture (ethanol-ethyl acetate) at delta1=22.59, 21.70 and 20.91 MPa1/2, respectively. Phenacetin displays two solubility maxima, at delta1=25.71 (ethanol-water) and at delta1=23.30 (ethyl acetate-ethanol). Acetanilide shows an inflexion point in ethanol-water instead of a peak, and the sign of the slope does not vary when changing the cosolvent. The solubility profiles were compared to those obtained in dioxane-water, having a solubility parameter range similar to that covered with the common cosolvent system. All the drugs reach a maximum at about 90% dioxane (delta1=23 MPa1/2). A modification of the extended Hildebrand method is applicable for curves with a single maximum whereas a model including the Hildebrand solubility parameter delta1 and the acidic partial solubility parameter delta1a is required to calculate more complex solubility profiles (with inflexion point or two maxima). A single equation was able to fit the solubility curves of all drugs in the common cosolvent system. The polarity of the drug is related to the shape of the solubility profile against the solubility parameter delta1 of the solvent mixtures. The drugs with solubility parameters below 24 MPa1/2 display a single peak in ethanol-ethyl acetate. The drugs with delta2 values above 25 MPa1/2 show two maxima, one in each solvent mixture (ethanol-water and ethanol-ethyl acetate). The position of the maximum in ethanol-ethyl acetate shifts to larger polarity values (higher delta1 values) as the solubility parameter of the drug delta2 increases.

  20. Neutron production with mixture of deuterium and krypton in Sahand Filippov type plasma focus facility

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, M.A., E-mail: mohammadidorbash@yahoo.com [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of); Sobhanian, S. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of); Rawat, R.S. [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore)

    2011-08-01

    This Letter reports the order of magnitude enhancement in neutron yield from Sahand plasma focus device with krypton seeded deuterium operation. The highest average neutron yield of 2.2x10{sup 9} neutrons per shot was achieved at 1.00 Torr deuterium with 3% krypton which is higher than the best average neutron yield of 3.18x10{sup 8} neutrons per shot for pure deuterium operation. Estimation of average neutron energy showed that the maximum and minimum average energies are 2.98±0.6 MeV at 16 kV in 0.25 Torr deuterium with 3% Kr and 2.07±0.2 MeV at 18 kV operation in 0.5 Torr deuterium with 3% Kr, respectively. The anisotropy of neutron emission from Sahand DPF showed that the neutrons are produced mainly by beam-target mechanisms. -- Highlights: → The highest average neutron yield of 2.2x10{sup 9} neutrons per shot was achieved at mixture of deuterium and krypton. → In the krypton seeding of deuterium also anisotropy of neutron emission deuterium is found. → The krypton seeding of deuterium made the neutron emission more reliable over wider operating pressure ranges.

  1. Prediction of Heat Transfer Characteristics of Binary Refrigerant Mixtures in a Falling Film Type Plate-fin Evaporator

    Science.gov (United States)

    Yara, Tomoyasu; Koyama, Shigeru

    This paper deals with the characteristics of heat transfer and pressure drop of R 22, R 134a pure refrigerant and R 134a/R123 refrigerant mixtures in a falling film type plate-fin evaporator. The refrigerants have been tested in the ranges of heat flux from 3 to 20 kW/m2 and mass velocity from 50 to 100 kg/m2s. It is clarified that heat transfer characteristics of evaporation in the present experimental range are not affected by shear stress. Taking the fin efficiency into consideration, a correlation equation of heat transfer coefficient is proposed. The characteristic of pressure drop is also proposed by modifying friction factor of Soliman's equation. Furthermore, a prediction model for evaporation of mixtures in a plate fin heat exchanger is developed based on the assumption that the phase equilibrium in a cross-section of the refrigerant path is established. The prediction results are in good agreement with the experimental data.

  2. A Robust Skin Colour Segmentation Using Bivariate Pearson Type IIαα (Bivariate Beta) Mixture Model

    OpenAIRE

    B.N.Jagadesh; Srinivasa Rao, K.; Ch.Satyanarayana

    2012-01-01

    Probability distributions formulate the basic framework for developing several segmentation algorithms. Among the various segmentation algorithms, skin colour segmentation is one of the most important algorithms for human computer interaction. Due to various random factors influencing the colour space, there does not exist a unique algorithm which serve the purpose of all images. In this paper a novel and new skin colour segmentation algorithms is proposed based on bivariate Pearson type I...

  3. Optimisation of belt-type electrostatic separation of granular plastic mixtures tribocharged in a propeller-type device

    Science.gov (United States)

    Miloudi, M.; Medles, K.; Tilmatine, A.; Brahami, M.; Dascalescu, L.

    2011-06-01

    Electrostatic separation has already proven its efficiency as a method to recover metals and plastics from granular waste electrical and electronic equipment (WEEE). Nevertheless, there still is some work to do regarding the sorting of the various sorts of plastics (ABS, ABS-PC, HIPS, PC) contained in information technology wastes. The main objective of this paper is to optimize the electrode configuration and the operation of a belt-type electrostatic separator employed in conjunction with a new tribo-aerodynamic charging device. This application is particularly designed for the recovery of granular materials issued from shredding of computer cases, which contain large quantities of ABS. The following control variables were considered for the optimization: (i) distance between the axis of the high-voltage electrode and the surface of the grounded belt electrode; (ii) angular position of the high-voltage electrode with respect to the horizontal plane; (iii) high-voltage level. Experimental design methodology was employed for determining the optimum value of each variable, using commercial software (MODDE, Umetrics, Sweden).

  4. Magnetic characteristics measurements of ethanol-water mixtures using a hybrid-type high-temperature superconducting quantum-interference device magnetometer

    Science.gov (United States)

    Tsukada, Keiji; Matsunaga, Yasuaki; Isshiki, Ryota; Nakamura, Yuta; Sakai, Kenji; Kiwa, Toshihiko

    2017-05-01

    The magnetic characteristics of ethanol-water mixtures were investigated using our newly developed hybrid-type magnetometer based on a high-temperature superconducting quantum-interference device. The magnetization (M-H) curves of ethanol-water mixtures show good diamagnetic characteristics. The magnetic moments of the mixture show ethanol concentration dependence. However, the variation in magnetic moment differs from the characteristics expected by considering the magnetic moment ratio between water and ethanol, and volume-reduction rate. It showed two decrement regions separated at approximately 50-60% concentration values. It is also observed that the concentration dependence of the magnetic moment measured using the sample vibration method under a uniform magnetic field and that by the sample rotation method showed slightly different characteristics. These anomalies are attributed to the formation of clustered structures in the mixture.

  5. Compaction properties, drug release kinetics and fronts movement studies of matrices combining mixtures of swellable and inert polymers. III: effect of polymer substitution type.

    Science.gov (United States)

    Escudero, J J; Ferrero, C; Casas, M; Jiménez-Castellanos, M R

    2012-09-15

    Theophylline radial release from cellulose derivatives with different substitution type (HPMC K4M, HPC H, MC A4M) matrix tablets has been modulated by the introduction of a new inert polymeric excipient, at different proportions (75, 50, 25%). The new polymer was hydroxypropylcellulose-methyl methacrylate (HCMMA), which was dried either in a vacuum oven (OD-HCMMA) or freeze-dried (FD-HCMMA). MC A4M and its mixtures presented the best compaction properties results, especially mixed with FD-HCMMA, according to 100% mixtures. Only high levels of HCMMA (75%) in the matrices showed interesting differences to drug release modulation. Also, at this proportion (75:25), the HPC H mixtures presented the highest differences in relation with OD or FD HCMMA respect to the other cellulose polymers. HPMC K4M and HPC H mixtures showed a combination of diffusion and erosion release mechanisms. The last one was nearly negligible in MC A4M mixtures, according with its highest diffusion rate constant values, and the absence of hydroxypropyl substituents. Only HPMC K4M mixtures presented a diffusion front that moves outwards, while HPC H and MC A4M moves inwards. The modulation of theophylline radial release was obtained using a high percentage of HCMMA, and the use of two cellulosic ethers, one of them with just one type of substituent (MC A4M or HPC H) and the other with two types of substituent (HPMC K4M). Another possibility is changing the HCMMA copolymer (OD or FD) in the 75/25 mixture with HPC. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. CONSOLIDATION AND COMPACTION OF POWDER MIXTURES .3. BINARY-MIXTURES OF DIFFERENT PARTICLE-SIZE FRACTIONS OF DIFFERENT TYPES OF CRYSTALLINE LACTOSE

    NARCIS (Netherlands)

    RIEPMA, KA; ZUURMAN, K; BOLHUIS, GK; DEBOER, AH; LERK, CF

    1992-01-01

    Tablets were compacted from a coarse fraction (250-315 mum), a fine fraction (32-45 mum) and from binary blends of a coarse and a fine fraction of different types of crystalline lactose. The results showed differences in consolidation and compaction between the granular lactose types, i.e., roller-d

  7. A theoretical model describing diffusion of a mixture of different types of ions in pore solution of concrete coupled to moisture transport

    OpenAIRE

    Johannesson, Björn

    2000-01-01

    A theoretical model is established for diffusion of different types of ions in pore solution of concrete and the coupling to moisture flow and moisture content. Mass exchanges between ions in pore solution and solid hydration products in the concrete are also considered. The basic concepts behind the so-called mixture theory are used.

  8. 沥青混合料结构类型的符合性检验方法%Conformance Testing Method of Asphalt Mixture Structure Types

    Institute of Scientific and Technical Information of China (English)

    葛折圣; 胡晓倩

    2012-01-01

    为解决施工后沥青混合料结构类型的验收问题,以路面芯样为对象研究了混合料结构类型的评价方法.该方法具体步骤为首先测定沥青路面芯样高度,然后燃烧路面芯样从而获得粗集料,最后通过干捣实法成型试样并测定试样高度.通过试验建立了沥青混合料结构类型的评价指标Hmix/HDRC和评价标准,即:当路面芯样高度小于等于试样高度时,沥青混合料为骨架型结构;当路面芯样高度大于试样高度时,沥青混合料为悬浮型结构.并以某高速公路3个标段的中面层AC - 20混合料和上面层SMA - 16混合料为例,研究了混合料结构类型对高温抗变形性能的影响,结果表明,所提出的混合料结构类型指标Hmix/HDRC与混合料高温抗变形性能密切相关.研究成果弥补了现有规范的不足,便于对沥青路面的施工质量与设计的符合性进行检验,从而有利于控制路面施工质量,延长路面使用寿命.%For acceptance of the structure types of asphalt mixture after construction, taken the core sample from pavement as the research object, a method for evaluating asphalt mixture structure types was studied. The steps of the evaluation method is as follows: measuring the height of the core sample from pavement, getting coarse aggregate through burning the core sample, shaping the contrast sample by the method of dry tamping, and measuring the height of the sample. The evaluation criterion and indicator Hmix/HDRC of asphalt mixture structure types were established through experiment; when the height of core sample is less than or equal to the height of contrast sample, the type structure of asphalt mixture is skeleton structure; if not, the type structure of asphalt mixture is suspended structure. Taken 3 kinds of AC -20 mixture in middle surface and 3 kinds of SMA-16 mixture in upper surface of 3 sections of an express way for example, the effect of mixture structure types on high

  9. Mixture Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.

    2007-12-01

    A mixture experiment involves combining two or more components in various proportions or amounts and then measuring one or more responses for the resulting end products. Other factors that affect the response(s), such as process variables and/or the total amount of the mixture, may also be studied in the experiment. A mixture experiment design specifies the combinations of mixture components and other experimental factors (if any) to be studied and the response variable(s) to be measured. Mixture experiment data analyses are then used to achieve the desired goals, which may include (i) understanding the effects of components and other factors on the response(s), (ii) identifying components and other factors with significant and nonsignificant effects on the response(s), (iii) developing models for predicting the response(s) as functions of the mixture components and any other factors, and (iv) developing end-products with desired values and uncertainties of the response(s). Given a mixture experiment problem, a practitioner must consider the possible approaches for designing the experiment and analyzing the data, and then select the approach best suited to the problem. Eight possible approaches include 1) component proportions, 2) mathematically independent variables, 3) slack variable, 4) mixture amount, 5) component amounts, 6) mixture process variable, 7) mixture of mixtures, and 8) multi-factor mixture. The article provides an overview of the mixture experiment designs, models, and data analyses for these approaches.

  10. Melting and solidification characteristics of a mixture of two types of latent heat storage material in a vessel

    Science.gov (United States)

    Yu, JikSu; Horibe, Akihiko; Haruki, Naoto; Machida, Akito; Kato, Masashi

    2016-11-01

    In this study, we investigated the fundamental melting and solidification characteristics of mannitol, erythritol, and their mixture (70 % by mass mannitol: 30 % by mass erythritol) as potential phase-change materials (PCMs) for latent heat thermal energy storage systems, specifically those pertaining to industrial waste heat, having temperatures in the range of 100-250 °C. The melting point of erythritol and mannitol, the melting peak temperature of their mixture, and latent heat were measured using differential scanning calorimetry. The thermal performance of the mannitol mixture was determined during melting and solidification processes, using a heat storage vessel with a pipe heat exchanger. Our results indicated phase-change (fusion) temperatures of 160 °C for mannitol and 113 and 150 °C for the mannitol mixture. Nondimensional correlation equations of the average heat transfer during the solidification process, as well as the temperature and velocity efficiencies of flowing silicon oil in the pipe and the phase-change material (PCM), were derived using several nondimensional parameters.

  11. Low Temperature Properties Of Fuel Mixtures Of Kerosene And Fame Type Used To Supply Turbine Engines In Marine And Other Non-Aeronautical Applications

    Directory of Open Access Journals (Sweden)

    Dzięgielewski Wojciech

    2015-04-01

    Full Text Available A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics. The article presents results of tests of low temperature properties of mixtures of the jet fuel Jet A-1 and methyl esters of higher fatty acids (FAME. The prepared mixtures contained different contents of FAME. The obtained results present changes of: viscosity, cloud point, pour point, crystallising point, and cold filter plugging point, depending on the percentage by volume of FAME. They also prove that the course of changes of low temperature properties of these mixtures is affected by chemical structure of the biocomponent.

  12. Characteristic of local boiling heat transfer of ammonia and ammonia / water binary mixture on the plate type evaporator

    Science.gov (United States)

    Okamoto, Akio; Arima, Hirofumi; Ikegami, Yasuyuki

    2011-08-01

    Power generation using small temperature difference such as ocean thermal energy conversion (OTEC) and discharged thermal energy conversion (DTEC) is expected to be the countermeasures against global warming problem. As ammonia and ammonia/water are used in evaporators for OTEC and DTEC as working fluids, the research of their local boiling heat transfer is important for improvement of the power generation efficiency. Measurements of local boiling heat transfer coefficients were performed for ammonia /water mixture ( z = 0.9-1) on a vertical flat plate heat exchanger in a range of mass flux (7.5-15 kg/m2 s), heat flux (15-23 kW/m2), and pressure (0.7-0.9 MPa). The result shows that in the case of ammonia /water mixture, the local heat transfer coefficients increase with an increase of mass flux and composition of ammonia, and decrease with an increase of heat flux.

  13. Analysis of asphalt mixtures on town roads

    OpenAIRE

    Glavica, Primož

    2006-01-01

    Asphalt mixtures are most commonly used composite for construction of top layers of different drive ways. By definition asphalt mixtures are composed of crushed rock, fill, bitumen and additives. Percentage of individual components wary according to the purpose asphalt mixture is to be used for. Asphalt mixtures must be capable of enduring different types of load. According to the type of load asphalt mixtures are divided into asphalt mixtures used for supporting layers and asp...

  14. Melting and freezing lines for a mixture of charged colloidal spheres with spindle-type phase diagram

    Science.gov (United States)

    Lorenz, Nina J.; Palberg, Thomas

    2010-09-01

    We have measured the phase behavior of a binary mixture of like-charged colloidal spheres with a size ratio of Γ =0.9 and a charge ratio of Λ =0.96 as a function of particle number density n and composition p. Under exhaustively deionized conditions, the aqueous suspension forms solid solutions of body centered cubic structure for all compositions. The freezing and melting lines as a function of composition show opposite behavior and open a wide, spindle shaped coexistence region. Lacking more sophisticated treatments, we model the interaction in our mixtures as an effective one-component pair energy accounting for number weighted effective charge and screening constant. Using this description, we find that within experimental error the location of the experimental melting points meets the range of melting points predicted for monodisperse, one-component Yukawa systems made in several theoretical approaches. We further discuss that a detailed understanding of the exact phase diagram shape including the composition dependent width of the coexistence region will need an extended theoretical treatment.

  15. Toxicity assessment of metoprolol and its photodegradation mixtures obtained by using different type of TiO{sub 2} catalysts in the mammalian cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Četojević-Simin, Dragana D., E-mail: ddaaggeerr@gmail.com [University of Novi Sad, Faculty of Medicine, Oncology Institute of Vojvodina, Dr Goldmana 4, 21204 Sremska Kamenica (Serbia); Armaković, Sanja J., E-mail: sanja.armakovic@dh.uns.ac.rs [University of Novi Sad, Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovića 3, 21000 Novi Sad (Serbia); Šojić, Daniela V., E-mail: daniela.sojic@dh.uns.ac.rs [University of Novi Sad, Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovića 3, 21000 Novi Sad (Serbia); Abramović, Biljana F., E-mail: biljana.abramovic@dh.uns.ac.rs [University of Novi Sad, Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovića 3, 21000 Novi Sad (Serbia)

    2013-10-01

    Toxicity of metoprolol (MET) alone and in mixtures with its photocatalytic degradation intermediates obtained by using TiO{sub 2} Wackherr and Degussa P25 under UV irradiation in the presence of O{sub 2} was evaluated in vitro in a panel of three histologically different cell lines: rat hepatoma (H-4-II-E), human colon adenocarcinoma (HT-29) and human fetal lung (MRC-5). Both catalysts promoted a time-dependent increase in the toxicity of the photodegradation products, and those obtained using Degussa P25 photocatalyst were more toxic. The most pronounced and selective toxic action of MET and products of its photodegradation was observed in the hepatic cell line. The higher toxicity of the mixtures obtained using Degussa P25 catalyst could be explained by a different mechanism of MET degradation, i.e. by the presence or higher concentrations of some intermediates. Although the concentrations of intermediates obtained using TiO{sub 2} Wackherr catalyst were higher, they did not affect significantly the growth of the examined cell lines, indicating their lower toxicity. This suggests that a treatment aiming at complete mineralization should be performed bearing in mind that the type of catalyst, the concentration of target molecule, and the duration of the process are significant factors that determine the nature and toxicity of the resulting mixtures. Although the EC{sub 50} values of MET obtained in mammalian cell lines were higher compared to the bioassays for lower trophic levels, the time-dependent promotion of toxicity of degradation mixtures should be attributed to the higher sensitivity of mammalian cell bioassays. - Highlights: • Toxicity study of metoprolol and its photocatalytic degradation mixtures • Toxicity evaluation in vitro in H-4-II-E, HT-29 and MRC-5 cell lines • TiO{sub 2} Wackherr and Degussa P25 promoted a time-dependent increase in toxicity. • The higher toxicity of degradation mixtures obtained using Degussa P25 • Most pronounced and

  16. Extended PCR conditions to reduce drop-out frequencies in low template STR typing including unequal mixtures.

    Science.gov (United States)

    Weiler, Natalie E C; Matai, Anuska S; Sijen, Titia

    2012-01-01

    Forensic laboratories employ various approaches to obtain short tandem repeat (STR) profiles from minimal traces (drop-out frequency is reduced for both pristine DNA and single or multiple donor mock case work samples. In addition, increased peak heights and slightly more drop-ins are observed while the heterozygous peak balance remains similar as with the conventional Identifiler protocol. By this extended protocol, full DNA profiles were obtained from only 12 sperm heads (which corresponds to 36 pg of DNA) that were collected by laser micro dissection. Notwithstanding the improved detection, allele drop-outs do persist, albeit in lower frequencies. Thus a LT interpretation strategy such as deducing consensus profiles from multiple independent amplifications is appropriate. The use of extended PCR conditions represents a general approach to improve detection of unequal mixtures as shown using four commercially available kits (AmpFℓSTR(®) Identifiler, SEfiler Plus, NGM and Yfiler). The extended PCR protocol seems to amplify more of the molecules in LT samples during PCR, which results in a lower drop-out frequency. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. A new type mixture refrigeration auto-cascade cycle with partial condensation and separation reflux exchanger and its preliminary experimental test

    Science.gov (United States)

    Wu, J. F.; Gong, M. Q.; Liu, J. L.; Luo, E. C.; Qi, Y. F.; Hu, Q. G.

    2002-05-01

    A new type of mixture refrigeration cycle with reflux exchanger is presented in this paper. In this cycle, a new type of L-V separator with inner heat and mass transfer is employed to replace the combination of conventional L-V separator or complicated rectifier and succeeding heat exchanger used in traditional auto-cascade cycle or Kleemenko cycle. A prototype is developed based on this refrigeration cycle. The thermodynamic performance is discussed as well as some other specifications such as cost, reliability, etc. The experimental results show that this prototype can reach 74 W at 135 K and 265 W at 171 K with a nominal input power of 1.5 HP.

  18. Mixing Rules Formulation for a Kinetic Model of the Langmuir-Hinshelwood Semipredictive Type Applied to the Heterogeneous Photocatalytic Degradation of Multicomponent Mixtures

    Directory of Open Access Journals (Sweden)

    John Wilman Rodriguez-Acosta

    2014-01-01

    Full Text Available Mixing rules coupled to a semipredictive kinetic model of the Langmuir-Hinshelwood type were proposed to determine the behavior of the heterogeneous solar photodegradation with TiO2-P25 of multicomponent mixtures at pilot scale. The kinetic expressions were expressed in terms of the effective concentration of total organic carbon (xTOC. An expression was obtained in a generalized form which is a function of the mixing rules as a product of a global contribution of the reaction rate constant k′ and a mixing function fC. Kinetic parameters of the model were obtained using the Nelder and Mead (N-M algorithm. The kinetic model was validated with experimental data obtained from the degradation of binary mixtures of chlorinated compounds (DCA: dichloroacetic acid and 4-CP: 4-chlorophenol at different initial global concentration, using a CPC reactor at pilot scale. A simplex-lattice {2,3} design experiment was adopted to perform the runs.

  19. Enhancement effect of mass imbalance on Fulde-Ferrell-Larkin-Ovchinnikov type of pairing in Fermi-Fermi mixtures of ultracold quantum gases

    Science.gov (United States)

    Wang, Jibiao; Che, Yanming; Zhang, Leifeng; Chen, Qijin

    2017-01-01

    Ultracold two-component Fermi gases with a tunable population imbalance have provided an excellent opportunity for studying the exotic Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states, which have been of great interest in condensed matter physics. However, the FFLO states have not been observed experimentally in Fermi gases in three dimensions (3D), possibly due to their small phase space volume and extremely low temperature required for an equal-mass Fermi gas. Here we explore possible effects of mass imbalance, mainly in a 6Li–40K mixture, on the one-plane-wave FFLO phases for a 3D homogeneous case at the mean-field level. We present various phase diagrams related to the FFLO states at both zero and finite temperatures, throughout the BCS-BEC crossover, and show that a large mass ratio may enhance substantially FFLO type of pairing.

  20. Enhancement effect of mass imbalance on Fulde-Ferrell-Larkin-Ovchinnikov type of pairing in Fermi-Fermi mixtures of ultracold quantum gases

    Science.gov (United States)

    Wang, Jibiao; Che, Yanming; Zhang, Leifeng; Chen, Qijin

    2017-01-01

    Ultracold two-component Fermi gases with a tunable population imbalance have provided an excellent opportunity for studying the exotic Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states, which have been of great interest in condensed matter physics. However, the FFLO states have not been observed experimentally in Fermi gases in three dimensions (3D), possibly due to their small phase space volume and extremely low temperature required for an equal-mass Fermi gas. Here we explore possible effects of mass imbalance, mainly in a 6Li–40K mixture, on the one-plane-wave FFLO phases for a 3D homogeneous case at the mean-field level. We present various phase diagrams related to the FFLO states at both zero and finite temperatures, throughout the BCS-BEC crossover, and show that a large mass ratio may enhance substantially FFLO type of pairing. PMID:28051145

  1. 不同类型冷补沥青混合料的初始强度研究%Study on initial strength of different types of cold patch asphalt mixtures

    Institute of Scientific and Technical Information of China (English)

    禤炜安

    2013-01-01

    在分析3种不同类型冷补沥青混合料(乳化类、溶剂类和反应类)的强度形成机理基础上,以AH-70为基质沥青成型相同级配的3种冷补沥青混合料马歇尔试件,并测定其马歇尔稳定度和单轴抗压强度,以此评价材料的初始强度.分析结果表明:不同类型冷补沥青混合料的初始强度差异较大;乳化类和溶剂类冷补沥青混合料的初始强度较低;反应类冷补沥青混合料由于加入固化剂后发生放热的化学反应,其初始强度明显大于其他两类的.通过吹风加热,能够提高乳化类和反应类冷补沥青混合料的初始强度,缩短道路开放交通时间.%On the basis of the strength formation mechanism about three different types of cold patch asphalt mixtures(the emulsification,the solvent and the reaction),AH-70is set as the base asphalt to mold the same gradation of cold patch asphalt mixture Marshall specimen,then their Marshall stability and uniaxial compressive strength are determined to evaluate the initial strength.The conclusion shows that initial strengths of different types of cold patch asphalt mixtures are quite different,i.e.,the initial strengths of the emulsification and the solvent-types cold patch asphalt mixtures are lower,and the initial strength of the reaction-type cold patch asphalt mixture is significantly larger than the other two types due to the exothermic chemical reaction after adding the curing agent.Through blowing and heating,it can improve the initial strength of the emulsification and the reaction-types cold patch asphalt mixtures,which can reduce the time open to traffic.

  2. Observation of Curative Effect of Feier Mixtures on Child Anorexia of Disharmony be-tween Spleen and Stomach Type%肥儿合剂治疗脾胃不和型小儿厌食症疗效观察

    Institute of Scientific and Technical Information of China (English)

    竺青华; 姚伟光; 徐佩华

    2015-01-01

    Objective:To observe the effect of Feier mixtures on serum leptin and cholecystokinin level of child anorexia of disharmony between spleen and stomach type. Methods:60 children who met the diagnosis standard of child anorexia of disharmony between spleen and stomach type were randomly divided into two groups:Feier Mixtures group and compound digestive enzyme capsule group. Each group had 30 children. The changes of serum leptin,cholecystokinin,scores of symptoms and signs,and comprehesive curative effect of the two groups after the treatment were observed. Results:After treatment,the curative effect of Feier Mixtures group was superior to compound digestive enzyme capsule group(P0 . 05 ) . The effect on lowering plasma CCK level of Feier Mixtures was superior to that of compound digestive enzyme capsule (P0.05),治疗组治疗后血浆CCK含量低于对照组(P<0.05)。结论:肥儿合剂可有效改善患儿厌食症状,能通过调节厌食症患儿血清LEP和血浆CCK水平对食欲产生影响。

  3. Optimal Parameters Multicomponent Mixtures Extruding

    Directory of Open Access Journals (Sweden)

    Ramil F. Sagitov

    2013-01-01

    Full Text Available Experimental research of multicomponent mixtures extruding from production wastes are carried out, unit for production of composites from different types of waste is presented. Having analyzed dependence of multicomponent mixtures extruding energy requirements on die length and components content at three values of angular rate of screw rotation, we received the values of energy requirements at optimal length of the die, angular speed and percent of binding additives.

  4. Organogel-emulsions with mixtures of ß-sitosterol + [gamma]-oryzanol: Influence of water activity and type of oil phase on gelling capability

    NARCIS (Netherlands)

    Sawalha, H.I.M.; Adel, den R.; Venema, P.; Bot, A.; Flöter, E.; Linden, van der E.

    2012-01-01

    In this study, w/o-emulsions were prepared from water containing different salt concentrations dispersed in an oil phase containing mixture of ß-sitosterol and ¿-oryzanol. In pure oil the ß-sitosterol and ¿-oryzanol molecules self-assemble into tubular microstructures to produce a firm organogel. Ho

  5. Mixture Density Mercer Kernels

    Data.gov (United States)

    National Aeronautics and Space Administration — We present a method of generating Mercer Kernels from an ensemble of probabilistic mixture models, where each mixture model is generated from a Bayesian mixture...

  6. Effect of hydrogel and different types of fertilizers on the number of turf shoots in lawns created by monocultures of red fescue (Festuca rubra L. cultivars and its mixtures

    Directory of Open Access Journals (Sweden)

    Kazimierz Jankowski

    2012-12-01

    Full Text Available In order to determine the effect of the hydrogel content in the soil substrate on the number of shoots per unit area of grass lawns with different proportions of red fescue and monoculture turf produced from the following fescue cultivars: Adio, Libano, Corail, Simone. In the period 2003-2004, a field experiment was carried out in a randomized block design in four replications. In combination with a hydrogel (Aqua-Gel P4, 0.05 kg x m-2 of sorbent was placed at a depth of 10 cm below the soil surface in 2002. Another experimental factor was the type of fertilizer. Trawovit (a fertilizer with standard effects and Sierrablen (a controlled-release fertilizer were used for this purpose. The quantities of fertilizer and time of fertilization date followed manufacturer's instructions. The number of shoots per 1 m2 was determined at the end of the growing season. The study showed that, regardless of years of cultivation, the type of soil substrate and fertilizer, the average number of shoots for the mixtures was about 32% lower than for monoculture lawns. The presence of the hydrogel in the soil substrate regulated soil moisture, and therefore in the mixture lawns the values of the tested features were significantly higher in the treatments with hydrogel. Fertilization with Trawovit, regardless of the type of soil substrate (H, BH, does not lead to a statistically significant difference in the number of shoots between the studied mixtures. However, in the treatments fertilized with Sierrablen, the presence of the hydrogel in the soil substrate caused a significant increase in the traits examined for the mixtures containing, respectively, 20 and 80% of red fescue in their composition. The addition of Aqua-Gel P4 to the soil substrate, when the turf lawns were fertilized with Trawovit, resulted in a significant increase in the number of shoots for the cultivars Adio, Libano and Corail.

  7. Low Temperature Properties Of Fuel Mixtures Of Kerosene And Fame Type Used To Supply Turbine Engines In Marine And Other Non-Aeronautical Applications

    OpenAIRE

    Dzięgielewski Wojciech; Gawron Bartosz; Kulczycki Andrzej

    2015-01-01

    A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene an...

  8. Performance of dairy heifers raised on Xaraés palissadgrass (Brachiaria brizantha cv. Xaraés pasture supplemented with two types of mineral mixture

    Directory of Open Access Journals (Sweden)

    Carlos Augusto B. de Carvalho

    2014-01-01

    Full Text Available The effects of selective (e.g. mineral supplement formulated on the basis of nutritional and clinical examination of the herd or commercial mineral supplementation of crossbred dairy heifers (Holstein-Mantiqueira, on daily weight gain (DWG, body condition score (BCS, age at first mating (AFM and the intake of mineral mixture (IMM managed on Xaraés palissadgrass pasture (Brachiaria brizantha cv. Xaraés were evaluated from February 2006 to March 2008. Structural characteristics, forage allowance and nutritional value of Xaraés palissadgrass were also evaluated. The structural variables of pasture, allowances and nutritive value of forage, besides the DWG were only affected (p<0.05 by season, with highest results for spring and summer. Throughout the experimental period (730 days, no sign of mineral deficiency was detected in heifers that ingested the selective supplement. The DWG and AFM were not influenced by the mineral mixture offered (0.52 and 0.33 kg/day during the spring/summer and in fall/winter for DWG, respectively, and 813 days of AFM. The IMM was higher for commercial mineral mixture than for selective (61.6 and 51.0g/day respectively. The BCS was slightly higher for selective (3.17 than for the commercial (3.02 mineral mixture. Thus, the selective mineral supplement was a strategy to prevent mineral deficiency in this herd and resulted in similar performance at lower costs (e.g. due to less IMM of crossbred heifers when compared with the commercial mineral supplementation.

  9. 沥青稳定类冷再生混合料抗剪特性研究%Study on Anti-shearing Behavior of Asphalt Stabilizing Type Cold Recycled Mixture

    Institute of Scientific and Technical Information of China (English)

    史永青

    2016-01-01

    Using emulsified asphalt and foamed asphalt as stabilizer of cold regenerated asphalt mixture, this paper studies 3 - axis shear behavior of cold regenerated asphalt mixture. Results show that the emulsified asphalt cold regenerated asphalt mixture has better anti -shearing behavior than that of the foamed asphalt cold regenerated asphalt mixture. Adding cement may obviously increase internal friction angle and cohesive strength of cold regenerated asphalt mixture; However, the cohesive strength has the trend of increase and reduce with the increasing of asphalt stabilizer, the internal friction angle reduces with the increment of asphalt, the major factor affect internal friction angle is composition of aggregate grains but not the types of asphalt stabilizer.%采用乳化沥青和泡沫沥青作为冷再生沥青混合料的稳定剂,研究冷再生混合料的三轴抗剪特性.研究表明:乳化沥青冷再生混合料比泡沫沥青冷再生混合料抗剪切强度略高;水泥的掺加能显著增加冷再生混合料的内摩擦角及粘聚力;而粘聚力随着沥青稳定剂用量的增大呈现先增大后减小的趋势,内摩擦角则随沥青用量增大而降低,且影响内摩擦角的主要因素为集料颗粒组成而非沥青稳定剂的类型.

  10. Alpha-tocopherol and β-carotene in legume-grass mixtures as influenced by wilting, ensiling and type of silage additive

    DEFF Research Database (Denmark)

    Lindqvist, H; Nadeau, E; Jensen, Søren Krogh

    2012-01-01

    2005. Forage was wilted to a dry-matter (DM) content of 273 g kg−1 and ensiled without additive or with an inoculant or acid. Wilting decreased α-tocopherol concentration by 30% in the Bft + Ti mixture (P = 0·015). Untreated Bft + Ti silage had higher α-tocopherol content than red clover silages (56......·9 vs. 34·2 mg kg−1 DM; P = 0·015). The α-tocopherol concentration of Bft + Ti forages increased during ensiling from 41·1 mg kg−1 DM in wilted herbage to 56·9, 65·2 and 56·8 mg kg−1 DM in untreated, inoculated and acid-treated silage respectively (P = 0·015). The inoculant increased α......-tocopherol content in the red clover silages (50·1 vs. 34·2 mg kg−1 DM; P = 0·015) compared with untreated red clover silages. Red clover mixtures had lower β-carotene content than Bft + Ti (32·3 vs. 46·2 mg kg−1 DM; P = 0·016), averaged over treatments. In conclusion, wilting had small effects but the use...

  11. Gene selection and cancer type classification of diffuse large-B-cell lymphoma using a bivariate mixture model for two-species data.

    Science.gov (United States)

    Su, Yuhua; Nielsen, Dahlia; Zhu, Lei; Richards, Kristy; Suter, Steven; Breen, Matthew; Motsinger-Reif, Alison; Osborne, Jason

    2013-01-05

    : A bivariate mixture model utilizing information across two species was proposed to solve the fundamental problem of identifying differentially expressed genes in microarray experiments. The model utility was illustrated using a dog and human lymphoma data set prepared by a group of scientists in the College of Veterinary Medicine at North Carolina State University. A small number of genes were identified as being differentially expressed in both species and the human genes in this cluster serve as a good predictor for classifying diffuse large-B-cell lymphoma (DLBCL) patients into two subgroups, the germinal center B-cell-like diffuse large B-cell lymphoma and the activated B-cell-like diffuse large B-cell lymphoma. The number of human genes that were observed to be significantly differentially expressed (21) from the two-species analysis was very small compared to the number of human genes (190) identified with only one-species analysis (human data). The genes may be clinically relevant/important, as this small set achieved low misclassification rates of DLBCL subtypes. Additionally, the two subgroups defined by this cluster of human genes had significantly different survival functions, indicating that the stratification based on gene-expression profiling using the proposed mixture model provided improved insight into the clinical differences between the two cancer subtypes.

  12. Optimal mixture experiments

    CERN Document Server

    Sinha, B K; Pal, Manisha; Das, P

    2014-01-01

    The book dwells mainly on the optimality aspects of mixture designs. As mixture models are a special case of regression models, a general discussion on regression designs has been presented, which includes topics like continuous designs, de la Garza phenomenon, Loewner order domination, Equivalence theorems for different optimality criteria and standard optimality results for single variable polynomial regression and multivariate linear and quadratic regression models. This is followed by a review of the available literature on estimation of parameters in mixture models. Based on recent research findings, the volume also introduces optimal mixture designs for estimation of optimum mixing proportions in different mixture models, which include Scheffé’s quadratic model, Darroch-Waller model, log- contrast model, mixture-amount models, random coefficient models and multi-response model.  Robust mixture designs and mixture designs in blocks have been also reviewed. Moreover, some applications of mixture desig...

  13. Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

    Science.gov (United States)

    Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S.; Katman, Herdayati; Husain, Nadiah Md

    2014-01-01

    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout. PMID:24526911

  14. Simulation of mixture microstructures via particle packing models and their direct comparison with real mixtures

    Science.gov (United States)

    Gulliver, Eric A.

    The objective of this thesis to identify and develop techniques providing direct comparison between simulated and real packed particle mixture microstructures containing submicron-sized particles. This entailed devising techniques for simulating powder mixtures, producing real mixtures with known powder characteristics, sectioning real mixtures, interrogating mixture cross-sections, evaluating and quantifying the mixture interrogation process and for comparing interrogation results between mixtures. A drop and roll-type particle-packing model was used to generate simulations of random mixtures. The simulated mixtures were then evaluated to establish that they were not segregated and free from gross defects. A powder processing protocol was established to provide real mixtures for direct comparison and for use in evaluating the simulation. The powder processing protocol was designed to minimize differences between measured particle size distributions and the particle size distributions in the mixture. A sectioning technique was developed that was capable of producing distortion free cross-sections of fine scale particulate mixtures. Tessellation analysis was used to interrogate mixture cross sections and statistical quality control charts were used to evaluate different types of tessellation analysis and to establish the importance of differences between simulated and real mixtures. The particle-packing program generated crescent shaped pores below large particles but realistic looking mixture microstructures otherwise. Focused ion beam milling was the only technique capable of sectioning particle compacts in a manner suitable for stereological analysis. Johnson-Mehl and Voronoi tessellation of the same cross-sections produced tessellation tiles with different the-area populations. Control charts analysis showed Johnson-Mehl tessellation measurements are superior to Voronoi tessellation measurements for detecting variations in mixture microstructure, such as altered

  15. Mixture Based Outlier Filtration

    Directory of Open Access Journals (Sweden)

    P. Pecherková

    2006-01-01

    Full Text Available Success/failure of adaptive control algorithms – especially those designed using the Linear Quadratic Gaussian criterion – depends on the quality of the process data used for model identification. One of the most harmful types of process data corruptions are outliers, i.e. ‘wrong data’ lying far away from the range of real data. The presence of outliers in the data negatively affects an estimation of the dynamics of the system. This effect is magnified when the outliers are grouped into blocks. In this paper, we propose an algorithm for outlier detection and removal. It is based on modelling the corrupted data by a two-component probabilistic mixture. The first component of the mixture models uncorrupted process data, while the second models outliers. When the outlier component is detected to be active, a prediction from the uncorrupted data component is computed and used as a reconstruction of the observed data. The resulting reconstruction filter is compared to standard methods on simulated and real data. The filter exhibits excellent properties, especially in the case of blocks of outliers. 

  16. Low temperature asphalt mixtures

    OpenAIRE

    Modrijan, Damjan

    2006-01-01

    This thesis presents the problem of manufacturing and building in the asphalt mixtures produced by the classical hot procedure and the possibility of manufacturing low temperature asphalt mixtures.We will see the main advantages of low temperature asphalt mixtures prepared with bitumen with organic addition Sasobit and compare it to the classical asphalt mixtures. The advantages and disadvantages of that are valued in the practical example in the conclusion.

  17. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  18. Dietary inositol hexakisphosphate, but not myo-inositol, clearly improves hypercholesterolemia in rats fed casein-type amino acid mixtures and 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane.

    Science.gov (United States)

    Okazaki, Yukako; Katayama, Tetsuyuki

    2008-10-01

    We have previously shown that dietary inositol hexakisphosphate (IP6) and myo-inositol prevent fatty liver in rats fed a casein-based diet containing 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT). This study was performed to examine the comparative effects of dietary equimolar amounts of sodium IP6 (1.02%) and myo-inositol (0.2%) on the development of DDT-induced fatty liver and hypercholesterolemia in rats fed 20% casein-type amino acid mixtures designed to exclude a possible myo-inositol contaminant in casein. Thirty-six male Wistar rats were divided into 6 groups of 6 rats each for: a control group, myo-inositol-supplemented group, IP6-supplemented group, DDT-treated group, DDT + myo-inositol-supplemented group, and a DDT + IP6-supplemented group. Dietary IP6 clearly suppressed the rises in serum concentrations of cholesterol and phospholipids because of DDT feeding, but myo-inositol had no significant influence on such elevations. Dietary IP6, but not myo-inositol, caused significant body weight gain with or without DDT intake. Supplemental IP6 and myo-inositol significantly increased hepatic-free myo-inositol regardless of DDT intake and prevented fatty liver in rats fed DDT. In conclusion, dietary IP6 and myo-inositol exert similar effects on DDT-induced fatty liver and myo-inositol status but distinct effects on DDT-induced hypercholesterolemia and growth rate in rats fed casein-type amino acid mixtures.

  19. Extension of LCVM-type mixing rule to three-parameter equations of state for vapor-liquid equilibria of mixtures

    Institute of Scientific and Technical Information of China (English)

    HAN Xiao-hong; CHEN Guang-ming; WANG Qin; CUI Xiao-long

    2005-01-01

    In this paper, the LCVM mixing rule is extended to the multi-parameter equations of state by combining infinite-pressure and zero-pressure mixing rule models. The new LCVM-type mixing rule, coupled with Patel-Teja equation of state(EOS) is applied for vapor-liquid equilibria of different polar and non-polar systems in which the NRTL activity coefficient model is used to calculate the excess Gibbs free energy. The tested results agree well with existing experimental data within a wide range of temperatures and pressures. In comparison with the Van der Waals mixing rule, the new mixing rule gives much better correlations for the vapor-liquid equilibria of non-polar and polar systems.

  20. Optical light curve of GRB 121011A: a textbook for the onset of GRB afterglow in a mixture of ISM and wind-type medium

    CERN Document Server

    Xin, Li-Ping; Qiu, Yu-Lei; Deng, Jin-Song; Wang, Jing; Han, Xu-Hui

    2016-01-01

    We reported the optical observations of GRB 121011A by 0.8-m TNT telescope at Xinglong observatory, China. The light curve of optical afterglow shows a smooth and featureless bump during the epoch of $\\sim$130 sec and $\\sim$5000 sec with a rising index of $1.57\\pm0.28$ before the break time of $539\\pm44$ sec, and a decaying index of about $1.29\\pm0.07$ up to the end of our observations. Meanwhile, the X-ray light curve decays in a single power-law with a slop of about $1.51\\pm0.03$ observed by $XRT$ onboard ${\\rm} Swift$ from 100 sec to about 10000 sec after the burst trigger. The featureless optical light curve could be understood as an onset process under the external-shock model. The typical frequency has been below or near the optical one before the deceleration time, and the cooling frequency is located between the optical and X-ray wavelengths. The external medium density has a transition from a mixed stage of ISM and wind-type medium before the peak time to the ISM at the later phase. The joint-analysi...

  1. An equiratio mixture model for non-additive components : a case study for aspartame/acesulfame-K mixtures

    NARCIS (Netherlands)

    Schifferstein, H.N.J.

    1996-01-01

    The Equiratio Mixture Model predicts the psychophysical function for an equiratio mixture type on the basis of the psychophysical functions for the unmixed components. The model reliably estimates the sweetness of mixtures of sugars and sugar-alchohols, but is unable to predict intensity for asparta

  2. Tailoring of structural, electrical and magnetic properties of BaCo{sub 2} W-type hexaferrites by doping with Zr-Mn binary mixtures for useful applications

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Javed, E-mail: mjiqauchem@yahoo.com [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-I-Azam University, Islamabad 45320 (Pakistan); Khan, Rafaqat Ali [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-I-Azam University, Islamabad 45320 (Pakistan); Mizukami, Shigemi; Miyazaki, Terunobu [WPI Advanced Institute for Material Research, Tohoku University, 2-1-1 Katahira, 980-8577 Sendai (Japan)

    2011-08-15

    Single-phase W-type hexaferrite, BaCo{sub 2}Fe{sub 16-2x}(ZrMn){sub x}O{sub 27} (x=0.0-1.0), has been synthesized by the chemical co-precipitation technique. Moessbauer analysis indicates substitution of Zr ions on tetrahedral (4e and 4f{sub IV}) sites and Mn ions on the octahedral '4f{sub VI} site' at low-doped concentration when the concentration is increased Mn ions but show preference for the octahedral '2b site'. The highest enhancement in the value of the room temperature resistivity of 2.82x10{sup 9} {Omega} cm has been obtained by doping with Zr-Mn content of x=0.6. The dissipation factor increases from 6.49x10{sup 3} to 9.97x10{sup 3} at 10 kHz with the addition of Zr-Mn dopants. Such materials are potentially suitable for electromagnetic attenuation purposes, for microwave absorption and as radar absorbing material. High values of saturation magnetization (67 emu/g) and remanent magnetization (34.7 emu/g) are obtained for substitution level of x=0.4 making them suitable for data processing devices. - Highlights: > Zirconium ions preference is for f{sub IV} sublattice while Mn ions prefer 4f{sub VI} and 2b sublattices. > Room temperature resistivity of up to 2.82x10{sup 9} {Omega} cm is obtained for doped hexaferrites. > High value of saturation magnetization (67.0 emu/g), remanent magnetization (34.7 emu/g) and coercivity (1861 Oe) make doped hexaferrites to be utilized as data processing devices.

  3. Simultaneous detection of several oligonucleotides by time-resolved fluorometry: the use of a mixture of categorized microparticles in a sandwich type mixed-phase hybridization assay.

    Science.gov (United States)

    Hakala, H; Virta, P; Salo, H; Lönnberg, H

    1998-12-15

    Porous, uniformly sized (50 micrometer) glycidyl methacrylate/ethylene dimethacrylate particles (SINTEF) were used as a solid phase to construct a sandwich type hybridization assay that allowed simultaneous detection of up to six oligonucleotides from a single sample. The assay was based on categorization of the particles by two organic prompt fluorophores, viz. fluorescein and dansyl, and quantification of the oligonucleotide hybridization by time-resolved fluorometry. Accordingly, allele-specific oligodeoxyribonucleotide probes were assembled on the particles by conventional phosphoramidite strategy using a non-cleavable linker, and the category defining fluorescein and/or dansyl tagged building blocks were inserted in the 3'-terminal sequence. An oligonucleotide bearing a photoluminescent europium(III) chelate was hybridized to the complementary 3'-terminal sequence of the target oligonucleotide, and the resulting duplex was further hybridized to the particle-bound allele-specific probes via the 5'-terminal sequence of the target. After hybridization each individual particle was subjected to three different fluorescence intensity measurements. The intensity of the prompt fluorescence signals of fluorescein and dansyl defined the particle category, while the europium(III) chelate emission quantified the hybridization. The length of the complementary region between the target oligonucleotide and the particle-bound probe was optimized to achieve maximal selectivity. Furthermore, the kinetics of hybridization and the effect of the concentration of the target oligomer on the efficiency of hybridization were evaluated. By this approach the possible presence of a three base deletion (DeltaF508), point mutation (G542X) and point deletion (1078delT) related to cystic fibrosis could unequivocally be detected from a single sample.

  4. Perception of trigeminal mixtures.

    Science.gov (United States)

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels.

  5. Coking technology using packed coal mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kuznichenko, V.M.; Shteinberg, Eh.A.; Tolstoi, A.P. (Khar' kovskii Nauchno-Issledovatel' skii Uglekhimicheskii Institut, Kharkov (Ukrainian SSR))

    1991-08-01

    Discusses coking of packed coal charges in the FRG, USSR, France, India, Poland and Czechoslovakia. The following aspects are evaluated: types of weakly caking coals that are used as components of packed mixtures, energy consumption of packing, effects of coal mixture packing on coke oven design, number of coke ovens in a battery, heating temperature, coking time, coke properties, investment and operating cost. Statistical data that characterize the Saarberg packing process used in the FRG are analyzed. Packing coal mixtures for coking improves coke quality and reduces environmental pollution. 4 refs.

  6. Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: High temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism

    Science.gov (United States)

    Yang, Hexiong; Ghose, Subrata; Hatch, Dorian M.

    1993-04-01

    Cryolite, Na3AlF6[ = 2Na+(Na0.5 +Al0.5 3+)F3] is a mixed fluoride perovskite, in which the corner-sharing octahedral framework is formed by alternating [NaF6] and [AlF6] octahedra and the cavities are occupied by Na+ ions. At 295 K, it is monoclinic ( α phase), space group P2 1/ n with a = 5.4139 (7), b = 5.6012 (5) and c = 7.7769 (8) Å and β = 90.183 (3)∘, Z = 2. A high temperature single crystal X-ray diffraction study in the range 295 900 K indicates a fluctuation-induced first-order phase transition from monoclinic to orthorhombic symmetry at T 0 ˜ 885 K, in contrast to a previous report that it becomes cubic at ˜823 K. The space group of the high temperature β phase is Immm with a = 5.632 (4), b = 5.627 (3) and c = 7.958 (4) Å, Z = 2 at 890 K. Above T 0, the coordination number of the Na+ ion in the cavity increases from eight to twelve and the zigzag Na1 — Al octahedral chains parallel to c become straight with the Na1-F-Al angle = 180 °. The phase transition is driven by two coupled primary order parameters. The first corresponds to the rotation of the nearly rigid [AlF6] group and transforms according to the Γ 4 + irreducible representation of Immm. Coupled to the [AlF6] rotation is a second primary order parameter corresponding to the displacement of the Na2+ ion in the cavity from its equilibrium position. This order parameter transforms according to the X 3 + irreducible representation of Immm. Following Immm → P2 1 / n phase transition, four equivalent domains of P2 1/ n are determined relative to Immm, which are in an antiphase and/or twin relationship. The abrupt shortening of the octahedral Al-F and Na-F bonds and a sudden change in orientations of the atomic thermal vibration ellipsoids above T 0 indicate a crossover from displacive to an order-disorder mechanism near the transition temperature. The β phase is interpreted as a dynamic average of four micro-twin and -antiphase domains of the a phase. This view is consistent with the

  7. A sealing mixture

    Energy Technology Data Exchange (ETDEWEB)

    Khayrullin, S.R.; Firsov, I.A.; Ongoyev, V.M.; Shekhtman, E.N.; Taskarin, B.T.

    1983-01-01

    A plugging mixture is proposed which contains triethanolamine, caustic soda, water and an additive. It is distinguished by the fact that in order to reduce the cost of the mixture while preserving its operational qualities, it additionally contains clay powder and as the additive, ground limestone with the following component ratio in percent by mass: ground limestone, 50 to 60; triethanolamine, 0.1 to 0.15; caustic soda, 2 to 3; clay powder, 8 to 10 and water the remainder. The mixture is distinguished by the fact that the ground limestone has a specific surface of 2,000 to 3,000 square centimeters per gram.

  8. Modeling methods for mixture-of-mixtures experiments applied to a tablet formulation problem.

    Science.gov (United States)

    Piepel, G F

    1999-01-01

    During the past few years, statistical methods for the experimental design, modeling, and optimization of mixture experiments have been widely applied to drug formulation problems. Different methods are required for mixture-of-mixtures (MoM) experiments in which a formulation is a mixture of two or more "major" components, each of which is a mixture of one or more "minor" components. Two types of MoM experiments are briefly described. A tablet formulation optimization example from a 1997 article in this journal is used to illustrate one type of MoM experiment and corresponding empirical modeling methods. Literature references that discuss other methods for MoM experiments are also provided.

  9. Peltier Heats in Cryolite Melts With Alumina

    Energy Technology Data Exchange (ETDEWEB)

    Flem, B.E.

    1996-12-31

    In the production of aluminium, improving the heat balance at the electrolytic cell may contribute to improve the energy conversion efficiency and the current efficiency of the process. The main purpose of this doctoral thesis was to measure Seebeck coefficients, or thermoelectric powers, to settle the question of reversible cooling or heating of the aluminium electrode and to decide the magnitude of the reversible Peltier effect of both the aluminium and the carbon electrode. The irreversible thermodynamics of thermocells is outlined. A thermocell using the binary system AlF{sub 3}-NaF and aluminium electrodes is described and the temperature dependence of the thermoelectric power is given. The system is extended by adding Al{sub 2}O{sub 3} to the molten electrolyte. Both thermocells with aluminium electrodes and oxygen electrodes are treated. The relevance of the thermocell measurements to the Hall-Heroult cell is discussed and an overview of trends in other thermocell systems is given. Measuring thermocell potentials of fluoride melts is complicated and so the experiments are covered in great detail. It is found that there is a reversible heat production at the cathode and a reversible cooling at the anode, which indicates that maximum temperature in the cell occurs at the cathode surface, not in the electrolyte as previously believed. When the electrolyte is saturated with both Al oxide and Al fluoride, the reversible heat effect at the cathode is approximately zero. This means that the cooling of the anode corresponds to the change of entropy in the reduction of Al oxide to Al and carbon dioxide. 186 refs., 23 figs., 25 tabs.

  10. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  11. 49 CFR 173.305 - Charging of cylinders with a mixture of compressed gas and other material.

    Science.gov (United States)

    2010-10-01

    ... nonflammable mixtures. Mixtures containing compressed gas or gases including insecticides, which mixtures are... relief devices of a type examined by the Bureau of Explosives and approved by the Associate...

  12. Mixtures Estimation and Applications

    CERN Document Server

    Mengersen, Kerrie; Titterington, Mike

    2011-01-01

    This book uses the EM (expectation maximization) algorithm to simultaneously estimate the missing data and unknown parameter(s) associated with a data set. The parameters describe the component distributions of the mixture; the distributions may be continuous or discrete. The editors provide a complete account of the applications, mathematical structure and statistical analysis of finite mixture distributions along with MCMC computational methods, together with a range of detailed discussions covering the applications of the methods and features chapters from the leading experts on the subject

  13. The effect of different composition of ternary mixtures of emulsifying salts on the consistency of processed cheese spreads manufactured from Swiss-type cheese with different degrees of maturity.

    Science.gov (United States)

    Salek, R N; Černíková, M; Maděrová, S; Lapčík, L; Buňka, F

    2016-05-01

    The scope of this work was to investigate the dependence of selected textural (texture profile analysis, TPA) and viscoelastic properties of processed cheese on the composition of ternary mixtures of emulsifying salts [disodium hydrogenphosphate, DSP; tetrasodium diphosphate, TSPP; sodium salt of polyphosphate (with mean length n ≈ 20), P20; and trisodium citrate, TSC] during a 60-d storage period (6±2°C). The processed cheese samples [40% wt/wt dry matter (DM) content, 50% wt/wt fat in DM content] were manufactured using Swiss-type cheese (as the main raw material) with 4 different maturity degrees (4, 8, 12, and 16 wk of ripening). Moreover, the pH of the samples was adjusted (the target values within the range of 5.60-5.80), corresponding to the standard pH values of spreadable processed cheese. With respect to the individual application of emulsifying salts (regardless of the maturity degree of the Swiss-type cheese applied), the samples prepared with P20 were the hardest, followed by those prepared with TSPP, TSC, and DSP. Furthermore, a specific ratio of DSP:TSPP (1:1) led to a significant increase in the hardness of the samples. On the whole, the hardness of all processed cheese samples increased with the prolonging storage period, whereas their hardness significantly dropped with the rising ripening stage of the raw material utilized. In all of the cases, the trends of hardness development remained analogous, and only the absolute values differed significantly. Moreover, the findings of TPA were in accordance with those of the rheological analysis. In particular, the specific ratio of DSP:TSPP (1:1) resulted in the highest gel strength and interaction factor values, followed by P20, TSPP, TSC, and DSP (used individually), reporting the same trend which was demonstrated by TPA. The monitored values of the gel strength and interaction factor decreased with the increasing maturity degree of the Swiss-type cheese used. The intensity of the rigidity of the

  14. Mixtures and interactions

    NARCIS (Netherlands)

    Groten, J.P.

    2000-01-01

    Drinking water can be considered as a complex mixture that consists of tens, hundreds or thousands of chemicals of which the composition is qualitatively and quantitatively not fully known. From a public health point of view it is most relevant to answer the question of whether chemicals in drinking

  15. Uniform designs for mixture-amount experiments and for mixture experiments under order restrictions

    Institute of Scientific and Technical Information of China (English)

    田国梁; 方开泰

    1999-01-01

    With order statistics of the uniform distribution on [0, 1], exponential and beta distributions, a stochastic representation is obtained for the uniform distribution over various domains, where A-type domains are closely associated with reliability growth analysis, order restricted statistical inference and isotonic regression theory, V-type domains are connected with the mixture-amount experiments, and T-type domains are well related to mixture experiments. With these stochastic representations, the corresponding uniform distribution and number-theoretic nets can be generated. This approach seems to be new and is called order statistics method. Some examples on reliability growth analysis and experimental design are presented.

  16. Molecular Dynamics Simulation of the Effect of AlF3 on Structure and Properties of Cryolite Melts%AlF3对冰晶石熔盐体系结构与性质影响的分子动力学模拟研究

    Institute of Scientific and Technical Information of China (English)

    田国才; 王永志

    2015-01-01

    The effect of AlF3 on the structure and properties of cryolite melts are studied by molecular dynamics simulations at 1283 K and 0.1 MPa.The radial distribution functions,coordination numbers,diffusion coeffi-cients,conductivities and viscosities of the systems are obtained.It is shown that the melts have fairly loose structure;that Al-F-Al fluorine bridge is formed in the melts;and that the main ion group is AlF3-6 octahe-dral.The coordination numbers of Al3+-F-and F--F-increase with increasing AlF3 mole fraction.As the AlF3 mole fraction increases,the diffusion coefficient and the conductivity decrease,and the viscosity increases first and then decreases.The effects of AlF3 on the ionic forms,mobility,ionic interactions,and diffusion mech-anisms of cryolite melts are revealed,which is important for the production of aluminum by electrolysis.%采用分子动力学方法研究了1283 K、0.1 MPa时不同摩尔分数的AlF3对冰晶石熔盐体系结构与性质的影响.获得了体系的密度、径向分布函数、配位数、扩散系数、电导率和粘度.结果显示熔体的结构比较疏松,熔体中Al主要的离子集团形式为AlF3-6八面体,且熔体中形成了Al-F-Al氟桥结构.随着AlF3含量的增加,Al3+-F-、F--F-间的配位数均增大,各离子的扩散系数减小,体系的电导率不断减小,粘度先增大后减小.研究工作揭示了AlF3对冰晶石熔盐体系中离子的存在形式、迁移性、离子间相互作用和扩散机制的影响,对铝电解生产具有重要的指导意义.

  17. Pointer Sentinel Mixture Models

    OpenAIRE

    Merity, Stephen; Xiong, Caiming; Bradbury, James; Socher, Richard

    2016-01-01

    Recent neural network sequence models with softmax classifiers have achieved their best language modeling performance only with very large hidden states and large vocabularies. Even then they struggle to predict rare or unseen words even if the context makes the prediction unambiguous. We introduce the pointer sentinel mixture architecture for neural sequence models which has the ability to either reproduce a word from the recent context or produce a word from a standard softmax classifier. O...

  18. A re-appraisal of the concept of ideal mixtures through a computer simulation study of the methanol-ethanol mixtures

    Science.gov (United States)

    Požar, Martina; Lovrinčević, Bernarda; Zoranić, Larisa; Mijaković, Marijana; Sokolić, Franjo; Perera, Aurélien

    2016-08-01

    Methanol-ethanol mixtures under ambient conditions of temperature and pressure are studied by computer simulations, with the aim to sort out how the ideality of this type of mixtures differs from that of a textbook example of an ideal mixture. This study reveals two types of ideality, one which is related to simple disorder, such as in benzene-cyclohexane mixtures, and another found in complex disorder mixtures of associated liquids. It underlines the importance of distinguishing between concentration fluctuations, which are shared by both types of systems, and the structural heterogeneity, which characterises the second class of disorder. Methanol-1propanol mixtures are equally studied and show a quasi-ideality with many respect comparable to that of the methanol-ethanol mixtures, hinting at the existence of a super-ideality in neat mono-ol binary mixtures, driven essentially by the strong hydrogen bonding and underlying hydroxyl group clustering.

  19. Phase and viscosity behaviour of refrigerant-lubricant mixtures

    DEFF Research Database (Denmark)

    Cisneros, Sergio; Garcia, J.; Fernandez, J.

    2005-01-01

    The understanding of thermophysical properties and phase behaviour of refrigerant-lubricant oil mixtures is highly important for the optimal design of refrigeration and air-conditioning systems. Refrigerant lubricant mixtures, which are likely to have strong asymmetry, can show complex phase...... behaviour such as closed miscibility gaps, open miscibility gaps, liquid-liquid-vapour equilibrium, and even barotropic phenomena (density inversions). In fact, the type of phase behaviour that refrigerant-lubricant mixtures may show is linked to the transition between different types of phase diagrams......, mainly as a function of the molecular asymmetry. This also has a profound effect in the mixture transport properties. Thus, in this work the general aspects of phase and viscosity behaviour linked to the type of asymmetry found in refrigerant-lubricant mixtures are discussed in the context of phase...

  20. Essays on Finite Mixture Models

    NARCIS (Netherlands)

    A. van Dijk (Bram)

    2009-01-01

    textabstractFinite mixture distributions are a weighted average of a ¯nite number of distributions. The latter are usually called the mixture components. The weights are usually described by a multinomial distribution and are sometimes called mixing proportions. The mixture components may be the

  1. Essays on Finite Mixture Models

    NARCIS (Netherlands)

    A. van Dijk (Bram)

    2009-01-01

    textabstractFinite mixture distributions are a weighted average of a ¯nite number of distributions. The latter are usually called the mixture components. The weights are usually described by a multinomial distribution and are sometimes called mixing proportions. The mixture components may be the sam

  2. Mixtures of truncated basis functions

    DEFF Research Database (Denmark)

    Langseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael

    2012-01-01

    In this paper we propose a framework, called mixtures of truncated basis functions (MoTBFs), for representing general hybrid Bayesian networks. The proposed framework generalizes both the mixture of truncated exponentials (MTEs) framework and the mixture of polynomials (MoPs) framework. Similar...

  3. Separating Underdetermined Convolutive Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2006-01-01

    a method for underdetermined blind source separation of convolutive mixtures. The proposed framework is applicable for separation of instantaneous as well as convolutive speech mixtures. It is possible to iteratively extract each speech signal from the mixture by combining blind source separation...

  4. Toxicological evaluation of chemical mixtures

    NARCIS (Netherlands)

    Feron, V.J.; Groten, J.P.

    2002-01-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures

  5. Mixture design: A review of recent applications in the food industry

    OpenAIRE

    Yeliz Buruk Şahin; Ezgi Aktar Demirtaş; Nimetullah Burnak

    2016-01-01

    Design of experiments (DOE) is a systematic approach to applying statistical methods to the experimental process. The main purpose of this study is to provide useful insights into mixture design as a special type of DOE and to present a review of current mixture design applications in the food industry. The theoretical principles of mixture design and its application in the food industry, based on an extensive review of the literature, are described. Mixture design types, such as simplex-latt...

  6. Concomitant variables in finite mixture models

    NARCIS (Netherlands)

    Wedel, M

    The standard mixture model, the concomitant variable mixture model, the mixture regression model and the concomitant variable mixture regression model all enable simultaneous identification and description of groups of observations. This study reviews the different ways in which dependencies among

  7. Comparison and Evaluation Research on High Viscosity Asphalt Types of Drainage Asphalt Mixture%排水沥青混合料高粘沥青类型的对比和评价研究

    Institute of Scientific and Technical Information of China (English)

    丁志勇

    2016-01-01

    Viscous asphalt is the core of the drainage asphalt mixture material.In this research,the high viscosity asphalt was produced using star-shaped and linear SBS respectively,on this basis,the pavement performance of OGFC-1 3 drainage asphalt mixture was tested in the laboratory.It was found that the pavement performance of asphalt mixture made by the star-shaped SBS was better than that made by the linear SBS through the wheel rutting test,beam bending test,freeze-thaw splitting test and water dispersion test.%高粘沥青是排水沥青混合料的核心材料。文中采用星型和线型 SBS改性沥青制备高粘沥青,在此基础上,室内成型 OGFC-13排水沥青混合料,并对沥青混合料的路用性能进行研究。通过往复车辙轮碾压试验、低温弯曲梁试验、冻融劈裂试验和浸水飞散试验进行对比。结果表明,采用星型 SBS制备的排水沥青混合料各项路用性能均优于线型 SBS排水沥青混合料。

  8. Protein mixtures: interactions and gelation

    OpenAIRE

    Ersch, C.

    2015-01-01

    Gelation is a ubiquitous process in the preparation of foods. As most foods are multi constituent mixtures, understanding gelation in mixtures is an important goal in food science. Here we presented a systematic investigation on the influence of molecular interactions on the gelation in protein mixtures. Gelatin gels with added globular protein and globular protein gels with added gelatin were analyzed for their gel microstructure and rheological properties. Mixed gels with altered microstruc...

  9. Neurotoxicity of Metal Mixtures.

    Science.gov (United States)

    Andrade, V M; Aschner, M; Marreilha Dos Santos, A P

    2017-01-01

    Metals are the oldest toxins known to humans. Metals differ from other toxic substances in that they are neither created nor destroyed by humans (Casarett and Doull's, Toxicology: the basic science of poisons, 8th edn. McGraw-Hill, London, 2013). Metals are of great importance in our daily life and their frequent use makes their omnipresence and a constant source of human exposure. Metals such as arsenic [As], lead [Pb], mercury [Hg], aluminum [Al] and cadmium [Cd] do not have any specific role in an organism and can be toxic even at low levels. The Substance Priority List of Agency for Toxic Substances and Disease Registry (ATSDR) ranked substances based on a combination of their frequency, toxicity, and potential for human exposure. In this list, As, Pb, Hg, and Cd occupy the first, second, third, and seventh positions, respectively (ATSDR, Priority list of hazardous substances. U.S. Department of Health and Human Services, Public Health Service, Atlanta, 2016). Besides existing individually, these metals are also (or mainly) found as mixtures in various parts of the ecosystem (Cobbina SJ, Chen Y, Zhou Z, Wub X, Feng W, Wang W, Mao G, Xu H, Zhang Z, Wua X, Yang L, Chemosphere 132:79-86, 2015). Interactions among components of a mixture may change toxicokinetics and toxicodynamics (Spurgeon DJ, Jones OAH, Dorne J-L, Svendsen C, Swain S, Stürzenbaum SR, Sci Total Environ 408:3725-3734, 2010) and may result in greater (synergistic) toxicity (Lister LJ, Svendsen C, Wright J, Hooper HL, Spurgeon DJ, Environ Int 37:663-670, 2011). This is particularly worrisome when the components of the mixture individually attack the same organs. On the other hand, metals such as manganese [Mn], iron [Fe], copper [Cu], and zinc [Zn] are essential metals, and their presence in the body below or above homeostatic levels can also lead to disease states (Annangi B, Bonassi S, Marcos R, Hernández A, Mutat Res 770(Pt A):140-161, 2016). Pb, As, Cd, and Hg can induce Fe, Cu, and Zn

  10. Friction characteristics for water-ethylene glycol mixture flow in horizontal tubes with new type of helically fins%乙二醇溶液水平新型多头内螺纹管内流阻特性

    Institute of Scientific and Technical Information of China (English)

    张吉礼; 王永辉; 马志先; 陈敬东

    2016-01-01

    建立了水平管内绝热流动阻力特性试验系统,试验研究了乙二醇溶液在两种新型多头内螺纹管内的流动特性.试验中,乙二醇体积分数为15%,两种试验管公称内径为22 mm与16 mm、螺纹头数为60头与38头、螺旋升角为45°与60°、相对粗糙高为0.022与0.053,测试段长度分别为2643 mm与2945 mm,Pr范围13.9~23.2,Re范围4000~33000.结果表明:多头内螺纹管阻力系数达到极大值之前的变化趋势与均匀粗糙管显著不同,而且无法通过既有多头内螺纹管经验模型准确描述;多头内螺纹管内达到阻力系数极大值的分界点Re为内肋结构参数的函数;入口效应对内螺纹管阻力系数的影响随Re增加而增大,传统的判别入口段可忽略的判据(l/di>60)并不适用于多头内螺纹管,尤其是在Re>20000的工况;既有多头内螺纹管经验模型适用工况条件有待进一步拓宽,多头内螺纹结构流动阻力的作用机制、阻力系数出现极大值的分界点的变化规律有待进一步试验探索.%An experiment setup was built for investigating single-phase adiabatic flow characteristics of internal helical-rib roughness. The friction characteristics for 15% (by volume) water-ethylene glycol mixture flow in three internal finned tubes (two types of new developed internal helical-fins) and a smooth tube were obtained. The parameters of test tubes are nominal inside diameters (22 mm and 16 mm), numbers of fins (60 and 38), helix angles (45° and 60°) and fin height to inside diameter ratios (0.022 and 0.053). The lengths of the internal helical-rib tubes in test section were 2643 mm and 2945 mm, respectively. The Prandtl number varied from 13.9 to 23.2 and the Reynolds number ranged from 4000 to 33000. The smooth-tube results were compared to the Filonenko equation with satisfactory agreement. The experimental results of different length and same type multi-start internal helically-finned tubes also showed that the

  11. Thermophysical Properties of Hydrocarbon Mixtures

    Science.gov (United States)

    SRD 4 NIST Thermophysical Properties of Hydrocarbon Mixtures (PC database for purchase)   Interactive computer program for predicting thermodynamic and transport properties of pure fluids and fluid mixtures containing up to 20 components. The components are selected from a database of 196 components, mostly hydrocarbons.

  12. Evaporating Drops of Alkane Mixtures

    OpenAIRE

    Guéna, Geoffroy; Poulard, Christophe; Cazabat, Anne-Marie

    2005-01-01

    22 pages 9 figures; Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained.

  13. Protein mixtures: interactions and gelation

    NARCIS (Netherlands)

    Ersch, C.

    2015-01-01

    Gelation is a ubiquitous process in the preparation of foods. As most foods are multi constituent mixtures, understanding gelation in mixtures is an important goal in food science. Here we presented a systematic investigation on the influence of molecular interactions on the gelation in protein mixt

  14. Evaporating Drops of Alkane Mixtures

    CERN Document Server

    Gu'ena, G; Poulard, C; Cazabat, Anne-Marie; Gu\\'{e}na, Geoffroy; Poulard, Christophe

    2005-01-01

    Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained.

  15. Protein mixtures: interactions and gelation

    NARCIS (Netherlands)

    Ersch, C.

    2015-01-01

    Gelation is a ubiquitous process in the preparation of foods. As most foods are multi constituent mixtures, understanding gelation in mixtures is an important goal in food science. Here we presented a systematic investigation on the influence of molecular interactions on the gelation in protein mixt

  16. Easy and flexible mixture distributions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Mabit, Stefan L.

    2013-01-01

    We propose a method to generate flexible mixture distributions that are useful for estimating models such as the mixed logit model using simulation. The method is easy to implement, yet it can approximate essentially any mixture distribution. We test it with good results in a simulation study...

  17. Computer simulation of rod-sphere mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Antypov, Dmytro

    2003-07-01

    Results are presented from a series of simulations undertaken to investigate the effect of adding small spherical particles to a fluid of rods which would otherwise represent a liquid crystalline (LC) substance. Firstly, a bulk mixture of Hard Gaussian Overlap particles with an aspect ratio of 3:1 and hard spheres with diameters equal to the breadth of the rods is simulated at various sphere concentrations. Both mixing-demixing and isotropic-nematic transition are studied using Monte Carlo techniques. Secondly, the effect of adding Lennard-Jones particles to an LC system modelled using the well established Gay-Berne potential is investigated. These rod-sphere mixtures are simulated using both the original set of interaction parameters and a modified version of the rod-sphere potential proposed in this work. The subject of interest is the internal structure of the binary mixture and its dependence on density, temperature, concentration and various parameters characterising the intermolecular interactions. Both the mixing-demixing behaviour and the transitions between the isotropic and any LC phases have been studied for four systems which differ in the interaction potential between unlike particles. A range of contrasting microphase separated structures including bicontinuous, cubic, and micelle-like arrangement have been observed in bulk. Thirdly, the four types of mixtures previously studied in bulk are subjected to a static magnetic field. A variety of novel phases are observed for the cases of positive and negative anisotropy in the magnetic susceptibility. These include a lamellar structure, in which layers of rods are separated by layers of spheres, and a configuration with a self-assembling hexagonal array of spheres. Finally, two new models are presented to study liquid crystal mixtures in the presence of curved substrates. These are implemented for the cases of convex and concave spherical surfaces. The simulation results obtained in these geometries

  18. Thermodynamic study of (anthracene + phenanthrene) solid state mixtures

    Science.gov (United States)

    Rice, James W.; Fu, Jinxia; Sandström, Emma; Ditto, Jenna C.; Suuberg, Eric M.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAH) are common components of many materials, such as petroleum and various types of tars. They are generally present in mixtures, occurring both naturally and as byproducts of fuel processing operations. It is important to understand the thermodynamic properties of such mixtures in order to understand better and predict their behavior (i.e., fate and transport) in the environment and in industrial operations. To characterize better the thermodynamic behavior of PAH mixtures, the phase behavior of a binary (anthracene + phenanthrene) system was studied by differential scanning calorimetry, X-ray diffraction, and the Knudsen effusion technique. Mixtures of (anthracene + phenanthrene) exhibit non-ideal mixture behavior. They form a lower-melting, phenanthrene-rich phase with an initial melting temperature of 372 K (identical to the melting temperature of pure phenanthrene) and a vapor pressure of roughly lnP/Pa = −2.38. The phenanthrene-rich phase coexists with an anthracene-rich phase when the mole fraction of phenanthrene (xP) in the mixture is less than or equal to 0.80. Mixtures initially at xP = 0.90 consist entirely of the phenanthrene-rich phase and sublime at nearly constant vapor pressure and composition, consistent with azeotrope-like behavior. Quasi-azeotropy was also observed for very high-content anthracene mixtures (2.5 < xP < 5) indicating that anthracene may accommodate very low levels of phenanthrene in its crystal structure. PMID:26973354

  19. Thermodynamic study of (anthracene + phenanthrene) solid state mixtures.

    Science.gov (United States)

    Rice, James W; Fu, Jinxia; Sandström, Emma; Ditto, Jenna C; Suuberg, Eric M

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAH) are common components of many materials, such as petroleum and various types of tars. They are generally present in mixtures, occurring both naturally and as byproducts of fuel processing operations. It is important to understand the thermodynamic properties of such mixtures in order to understand better and predict their behavior (i.e., fate and transport) in the environment and in industrial operations. To characterize better the thermodynamic behavior of PAH mixtures, the phase behavior of a binary (anthracene + phenanthrene) system was studied by differential scanning calorimetry, X-ray diffraction, and the Knudsen effusion technique. Mixtures of (anthracene + phenanthrene) exhibit non-ideal mixture behavior. They form a lower-melting, phenanthrene-rich phase with an initial melting temperature of 372 K (identical to the melting temperature of pure phenanthrene) and a vapor pressure of roughly lnP/Pa = -2.38. The phenanthrene-rich phase coexists with an anthracene-rich phase when the mole fraction of phenanthrene (xP) in the mixture is less than or equal to 0.80. Mixtures initially at xP = 0.90 consist entirely of the phenanthrene-rich phase and sublime at nearly constant vapor pressure and composition, consistent with azeotrope-like behavior. Quasi-azeotropy was also observed for very high-content anthracene mixtures (2.5 anthracene may accommodate very low levels of phenanthrene in its crystal structure.

  20. Mechanistic and Economical Characteristics of Asphalt Rubber Mixtures

    Directory of Open Access Journals (Sweden)

    Mena I. Souliman

    2016-01-01

    Full Text Available Load associated fatigue cracking is one of the major distress types occurring in flexible pavement systems. Flexural bending beam fatigue laboratory test has been used for several decades and is considered to be an integral part of the new superpave advanced characterization procedure. One of the most significant solutions to prolong the fatigue life for an asphaltic mixture is to utilize flexible materials as rubber. A laboratory testing program was performed on a conventional and Asphalt Rubber- (AR- gap-graded mixtures to investigate the impact of added rubber on the mechanical, mechanistic, and economical attributes of asphaltic mixtures. Strain controlled fatigue tests were conducted according to American Association of State Highway and Transportation Officials (AASHTO procedures. The results from the beam fatigue tests indicated that the AR-gap-graded mixtures would have much longer fatigue life compared with the reference (conventional mixtures. In addition, a mechanistic analysis using 3D-Move software coupled with a cost analysis study based on the fatigue performance on the two mixtures was performed. Overall, analysis showed that AR modified asphalt mixtures exhibited significantly lower cost of pavement per 1000 cycles of fatigue life per mile compared to conventional HMA mixture.

  1. Phase structure of liposome in lipid mixtures.

    Science.gov (United States)

    Zhang, Tianxi; Li, Yuzhuo; Mueller, Anja

    2011-11-01

    Gas microbubbles present in ultrasound imaging contrast agents are stabilized by lipid aggregates that typically contain a mixture of lipids. In this study, the phase structure of the lipid mixtures that contained two or three lipids was investigated using three different methods: dynamic light scattering, (1)H NMR, and microfluidity measurements with fluorescence probes. Three lipids that are commonly present in imaging agents (DPPC, DPPE-PEG, and DPPA) were used. Two types of systems, two-lipid model systems and simulated imaging systems were investigated. The results show that liposomes were the dominant aggregates in all the samples studied. The polar PEG side chains from the PEGylated lipid lead to the formation of micelles and micellar aggregates in small sizes. In the ternary lipid systems, almost all the lipids were present in bilayers with micelles absent and free lipids at very low concentration. These results suggest that liposomes, not micelles, contribute to the stabilization of microbubbles in an ultrasound imaging contrast agent.

  2. Sensitivity of Some Explosive/Brine Mixtures

    Science.gov (United States)

    1980-08-01

    concentration in brine mixtures. 3 Friction test results of brine mixtures. 10 4 Thermal test results of brine mixtures. 11 Li 71 - INTRODUCTION A...also carried out on these impact insensitive mixtures. Of the seven mixtures only the 15% M28-Comp. B sample passed the thermal test , since smoking

  3. SANS studies of critical phenomena in ternary mixtures

    CERN Document Server

    Bulavyn, L A; Hohryakov, A; Garamus, V; Avdeev, M; Almasy, L

    2002-01-01

    Critical behaviour of a quasi-binary liquid mixture is investigated by small-angle neutron scattering. Analysis of the changes of the critical parameters, caused by addition of a small amount of electrolyte into the binary mixture 3-methylpyridine-heavy water, shows that the third component does not change the 3D Ising-type behaviour of the system; a crossover towards the mean-field behaviour is not observed. (orig.)

  4. Gaussian-mixture umbrella sampling

    OpenAIRE

    Maragakis, Paul; van der Vaart, Arjan; Karplus, Martin

    2009-01-01

    We introduce the Gaussian-mixture umbrella sampling method (GAMUS), a biased molecular dynamics technique based on adaptive umbrella sampling that efficiently escapes free energy minima in multi-dimensional problems. The prior simulation data are reweighted with a maximum likelihood formulation, and the new approximate probability density is fit to a Gaussian-mixture model, augmented by information about the unsampled areas. The method can be used to identify free energy minima in multi-dimen...

  5. SGC tests for influence of material composition on compaction characteristic of asphalt mixtures.

    Science.gov (United States)

    Chen, Qun; Li, Yuzhi

    2013-01-01

    Compaction characteristic of the surface layer asphalt mixture (13-type gradation mixture) was studied using Superpave gyratory compactor (SGC) simulative compaction tests. Based on analysis of densification curve of gyratory compaction, influence rules of the contents of mineral aggregates of all sizes and asphalt on compaction characteristic of asphalt mixtures were obtained. SGC Tests show that, for the mixture with a bigger content of asphalt, its density increases faster, that there is an optimal amount of fine aggregates for optimal compaction and that an appropriate amount of mineral powder will improve workability of mixtures, but overmuch mineral powder will make mixtures dry and hard. Conclusions based on SGC tests can provide basis for how to adjust material composition for improving compaction performance of asphalt mixtures, and for the designed asphalt mixture, its compaction performance can be predicted through these conclusions, which also contributes to the choice of compaction schemes.

  6. Familial searching on DNA mixtures with dropout.

    Science.gov (United States)

    Slooten, K

    2016-05-01

    Familial searching, the act of searching a database for a relative of an unknown individual whose DNA profile has been obtained, is usually restricted to cases where the DNA profile of that person has been unambiguously determined. Therefore, it is normally applied only with a good quality single source profile as starting point. In this article we investigate the performance of the method if applied to mixtures with and without allelic dropout, when likelihood ratios are computed with a semi-continuous (binary) model. We show that mixtures with dropout do not necessarily perform worse than mixtures without, especially if some separation between the donors is possible due to their different dropout probabilities. The familial searching true and false positive rates of mixed profiles on 15 loci are in some cases better than those of single source profiles on 10 loci. Thus, the information loss due to the fact that the person of interest's DNA has been mixed with that of other, and is affected by dropout, can be less than the loss of information corresponding to having 5 fewer loci available for a single source trace. Profiles typed on 10 autosomal loci are often involved in familial searching casework since many databases, including the Dutch one, in part consist of such profiles. Therefore, from this point of view, there seems to be no objection to extend familial searching to mixed or degraded profiles.

  7. Tandem mass spectrometry: analysis of complex mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, K.E.

    1985-01-01

    Applications of tandem mass spectrometry (MS/MS) for the analysis of complex mixtures results in increased specificity and selectivity by using a variety of reagent gases in both negative and positive ion modes. Natural isotopic abundance ratios were examined in both simple and complex mixtures using parent, daughter and neutral loss scans. MS/MS was also used to discover new compounds. Daughter scans were used to identify seven new alkaloids in a cactus species. Three of these alkaloids were novel compounds, and included the first simple, fully aromatic isoquinoline alkaloids reported in Cactaceae. MS/MS was used to characterize the chemical reaction products of coal in studies designed to probe its macromolecular structure. Negative ion chemical ionization was utilized to study reaction products resulting from the oxidation of coal. Possible structural units in the precursor coal were predicted based on the reaction products identified, aliphatic and aromatic acids and their anhydrides. The MS/MS method was also used to characterize reaction products resulting from coal liquefaction and/or extraction. These studies illustrate the types of problems for which MS/MS is useful. Emphasis has been placed on characterization of complex mixtures by selecting experimental parameters which enhance the information obtained. The value of using MS/MS in conjunction with other analytical techniques as well as the chemical pretreatment is demonstrated.

  8. Confusion of concepts in mixture toxicology.

    Science.gov (United States)

    Könemann, W H; Pieters, M N

    1996-01-01

    Regulatory limit values are generally set for single compounds. However, humans are exposed both simultaneously and sequentially to a wide variety of compounds. Some concepts on mixture toxicology are discussed in this introduction to the European Conference on Combination Toxicology. Studies on mixtures are often accompanied by statements about the type of combined action, which can be, for example, additive, synergistic or antagonistic. Unfortunately, comparison of results is hardly possible for various reasons. First, the terminology for indicating combined action is far from consistent. Bearing this in mind, researchers should be explicit in the definitions of terms. Secondly, depending on the model, different conclusions may be drawn from the same results. It is therefore important to provide clear definitions of the null hypothesis. Thirdly, adequate statistical methods should be used for testing the null hypothesis. In the past, many mixtures studies either used no statistics or used statistics incorrectly. Last, but not least, the study should be designed in such a way that it should be possible to obtain clear answers. In this introduction, it is stressed that environmental toxicologists should focus on the low-dose region of the dose-effect curves. It appears that interactions are less plausible at low doses. Dose additivity, however, cannot be excluded.

  9. Separating Dust Mixtures and Other External Aerosol Mixtures Using Airborne High Spectral Resolution Lidar Data

    Science.gov (United States)

    Burton, S. P.; Ferrare, R. A.; Vaughan, M.; Hostetler, C. A.; Rogers, R. R.; Hair, J. W.; Cook, A. L.; Harper, D. B.

    2013-12-01

    Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) has acquired considerable datasets of both aerosol extensive parameters (e.g. aerosol optical depth) and intensive parameters (e.g. aerosol depolarization ratio, lidar ratio) that can be used to infer aerosol type. An aerosol classification methodology has been used extensively to classify HSRL-1 aerosol measurements of different aerosol types including dust, smoke, urban pollution, and marine aerosol. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. Here we present a comprehensive and unified set of rules for characterizing external mixtures using several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. Our mixing rules apply not just to the scalar values of aerosol intensive parameters, but to multi-dimensional normal distributions with variance in each measurement dimension. We illustrate the applicability of the mixing rules using examples of HSRL-1 data where mixing occurred between different aerosol types, including advected Saharan dust mixed with the marine boundary layer in the Caribbean Sea and locally generated dust mixed with urban pollution in the Mexico City surroundings. For each of these cases we infer a time-height cross section of mixing ratio along the flight track and we partition aerosol extinction into portions attributed to the two pure types. Since multiple aerosol intensive parameters are measured and included in these calculations, the techniques can also be used for cases without significant depolarization (unlike similar work by earlier researchers), and so a third example of a

  10. Effects of Fibers on the Dynamic Properties of Asphalt Mixtures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The dynamic characteristics of fiber-modified asphalt mixture were investigated. Cellulose fiber, polyester fiber and mineral fiber were used as additives for asphalt mixture, and the dosage was 0.3%, 0.3%,0.4%, respectively. Dynamic modulus test using SuperPave simple performance tester (SPT) was conducted to study the dynamic modulus (E*) and phase angle (δ) for the control asphalt mixture and fiber-modified ones at various temperatures and frequencies. Experimental results show that all fiber-modified asphalt mixtures have higher dynamic modulus compared with control mixture. The dynamic modulus master curves of each type of asphalt mixtures are determined based on nonlinear least square regression in accordance with the timetemperature superposition theory at a control temperature (21.1 ℃). The fatigue parameter E*×sinδ and rutting parameter E*/sinδ of asphalt mixture are adopted to study the fatigue and rutting-resistance properties, and experimental results indicate that such properties can be improved by fiber additives.

  11. Flows and chemical reactions in heterogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2014-01-01

    This book - a sequel of previous publications 'Flows and Chemical Reactions' and 'Chemical Reactions in Flows and Homogeneous Mixtures' - is devoted to flows with chemical reactions in heterogeneous environments.  Heterogeneous media in this volume include interfaces and lines. They may be the site of radiation. Each type of flow is the subject of a chapter in this volume. We consider first, in Chapter 1, the question of the generation of environments biphasic individuals: dusty gas, mist, bubble flow.  Chapter 2 is devoted to the study at the mesoscopic scale: particle-fluid exchange of mom

  12. Thermal behavior of crumb-rubber modified asphalt concrete mixtures

    Science.gov (United States)

    Epps, Amy Louise

    Thermal cracking is one of the primary forms of distress in asphalt concrete pavements, resulting from either a single drop in temperature to an extreme low or from multiple temperature cycles above the fracture temperature of the asphalt-aggregate mixture. The first mode described is low temperature cracking; the second is thermal fatigue. The addition of crumb-rubber, manufactured from scrap tires, to the binder in asphalt concrete pavements has been suggested to minimize both types of thermal cracking. Four experiments were designed and completed to evaluate the thermal behavior of crumb-rubber modified (CRM) asphalt-aggregate mixtures. Modified and unmodified mixture response to thermal stresses was measured in four laboratory tests. The Thermal Stress Restrained Specimen Test (TSRST) and the Indirect Tensile Test (IDT) were used to compare mixture resistance to low temperature cracking. Modified mixtures showed improved performance, and cooling rate did not affect mixture resistance according to the statistical analysis. Therefore results from tests with faster rates can predict performance under slower field rates. In comparison, predicted fracture temperatures and stresses (IDT) were generally higher than measured values (TSRST). In addition, predicted fracture temperatures from binder test results demonstrated that binder testing alone is not sufficient to evaluate CRM mixtures. Thermal fatigue was explored in the third experiment using conventional load-induced fatigue tests with conditions selected to simulate daily temperature fluctuations. Test results indicated that thermal fatigue may contribute to transverse cracking in asphalt pavements. Both unmodified and modified mixtures had a finite capacity to withstand daily temperature fluctuations coupled with cold temperatures. Modified mixtures again exhibited improved performance. The fourth experiment examined fracture properties of modified and unmodified mixtures using a common fracture toughness test

  13. Independent components in spectroscopic analysis of complex mixtures

    CERN Document Server

    Monakhova, Yulia B; Kraskov, Alexander; Mushtakova, Svetlana P; 10.1016/j.chemolab.2010.05.023

    2010-01-01

    We applied two methods of "blind" spectral decomposition (MILCA and SNICA) to quantitative and qualitative analysis of UV absorption spectra of several non-trivial mixture types. Both methods use the concept of statistical independence and aim at the reconstruction of minimally dependent components from a linear mixture. We examined mixtures of major ecotoxicants (aromatic and polyaromatic hydrocarbons), amino acids and complex mixtures of vitamins in a veterinary drug. Both MICLA and SNICA were able to recover concentrations and individual spectra with minimal errors comparable with instrumental noise. In most cases their performance was similar to or better than that of other chemometric methods such as MCR-ALS, SIMPLISMA, RADICAL, JADE and FastICA. These results suggest that the ICA methods used in this study are suitable for real life applications.

  14. Mixture Segmentation of Multispectral MR Brain Images for Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Lihong Li

    2005-04-01

    Full Text Available We present a fully automatic mixture model-based tissue classification of multispectral (T1- and T2-weighted magnetic resonance (MR brain images. Unlike the conventional hard classification with a unique label for each voxel, our method models a mixture to estimate the partial volumes (PV of multiple tissue types within a voxel. A new Markov random field (MRF model is proposed to reflect the spatial information of tissue mixtures. A mixture classification algorithm is performed by the maximum a posterior (MAP criterion, where the expectation maximization (EM algorithm is utilized to estimate model parameters. The algorithm interleaves segmentation with parameter estimation and improves classification in an iterative manner. The presented method is evaluated by clinical MR image datasets for quantification of brain volumes and multiple sclerosis (MS.

  15. Marangoni Convection in Binary Mixtures

    CERN Document Server

    Zhang, J; Oron, A; Behringer, Robert P.; Oron, Alexander; Zhang, Jie

    2006-01-01

    Marangoni instabilities in binary mixtures are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of sodium chloride/water, we have systematically investigated the pattern formation for a set of substrate temperatures and solute concentrations in an open system. The flow patterns evolve with time, driven by surface-tension fluctuations due to evaporation and the Soret effect, while the air-liquid interface does not deform. A shadowgraph method is used to follow the pattern formation in time. The patterns are mainly composed of polygons and rolls. The mean pattern size first decreases slightly, and then gradually increases during the evolution. Evaporation affects the pattern formation mainly at the early stage and the local evaporation rate tends to become spatially uniform at the film surface. The Soret effect becomes i...

  16. Mixtures of skewed Kalman filters

    KAUST Repository

    Kim, Hyoungmoon

    2014-01-01

    Normal state-space models are prevalent, but to increase the applicability of the Kalman filter, we propose mixtures of skewed, and extended skewed, Kalman filters. To do so, the closed skew-normal distribution is extended to a scale mixture class of closed skew-normal distributions. Some basic properties are derived and a class of closed skew. t distributions is obtained. Our suggested family of distributions is skewed and has heavy tails too, so it is appropriate for robust analysis. Our proposed special sequential Monte Carlo methods use a random mixture of the closed skew-normal distributions to approximate a target distribution. Hence it is possible to handle skewed and heavy tailed data simultaneously. These methods are illustrated with numerical experiments. © 2013 Elsevier Inc.

  17. Structure of a binary mixture under shear: non-Newtonian effects from computer simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, H.J.M.; Evans, D.J.; Hess, S.

    1983-02-01

    A binary equimolar dense fluid mixture is subjected to a shear. The orientational distribution of particles of type i around particles of type j (i, j = 1, 2) and the distortion of the radial distribution function is discussed for planar Couette flow. Results are presented in terms of a mixture of soft spheres, for which one species differs substantially in size and mass from the other, simulated on the computer using the technique of shear nonequilbrium molecular dynamics. Transport coefficients, including those associated with normal pressure differences, are given for the mixture and for the species in the mixture. Non-Newtonian phenomena are observed.

  18. Taylor dispersion analysis of mixtures.

    Science.gov (United States)

    Cottet, Hervé; Biron, Jean-Philippe; Martin, Michel

    2007-12-01

    Taylor dispersion analysis (TDA) is a fast and simple method for determining hydrodynamic radii. In the case of sample mixtures, TDA, as the other nonseparative methods, leads to an average diffusion coefficient on the different molecules constituting the mixture. We set in this work the equations giving, on a consistent basis, the average values obtained by TDA with detectors with linear response functions. These equations confronted TDA experiments of sample mixtures containing different proportions of a small molecule and a polymer standard. Very good agreement between theory and experiment was obtained. In a second part of this work, on the basis of monomodal or bimodal molar mass distributions of polymers, the different average diffusion coefficients corresponding to TDA were compared to the z-average diffusion coefficient (D(z)) obtained from dynamic light scattering (DLS) experiments and to the weight average diffusion coefficient (D(w)). This latter value is sometimes considered as the most representative of the sample mixture. From these results, it appears that, for monomodal distribution and relatively low polydispersity (I = 1.15), the average diffusion coefficient generally derived from TDA is very close to Dw. However, for highly polydisperse samples (e.g., bimodal polydisperse distributions), important differences could be obtained (up to 35% between TDA and D(w)). In all the cases, the average diffusion coefficient obtained by TDA for a mass concentration detector was closer to the Dw value than the z-average obtained by DLS.

  19. Miscibility comparison for three refrigerant mixtures and four component refrigerants

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H.M.; Pate, M.B.

    1999-07-01

    Miscibility data were taken and compared for seven different refrigerants when mixed with the same polyol ester (POE) lubricant. Four of the seven refrigerants were single-component refrigerants while three of the refrigerants were mixtures composed of various combinations of the pure refrigerants. The purpose of this research was to investigate the difference in miscibility characteristics between refrigerant mixtures and their respective component refrigerants. The POE lubricant was a penta erythritol mixed-acid type POE which has a viscosity ISO32. The four pure refrigerants were R-32, R-125, R-134a, and R-143a and the three refrigerant mixtures were R-404A, R407C, and R-410A. The miscibility tests were performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The test cells were constructed to allow for complete visibility of the refrigerant/lubricant mixtures under all test conditions. The tests were performed over a concentration range of 0 to 100% and a temperature range of {minus}40 to 194 F. The miscibility test results for refrigerant mixtures are compared to component refrigerants. In all cases, the refrigerant mixtures appear to have better miscibility than their most immiscible pure component.

  20. Evaluation of Hydrated Lime Filler in Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Mohammed Abbas Hasan Al-Jumaily

    2008-01-01

    Full Text Available Mineral filler is one of important materials and affecting on properties and quality of asphalt mixtures .There are different types of mineral filler depended on cost and quality , the matter encourages us to achieve this study to evaluate hydrated lime filler effects on properties of asphalt mixes related with strength and durability. Conventional asphaltic concrete mixtures with Portland cement and soft sandstone fillers and mixtures modified with hydrated lime were evaluated for their fundamental engineering properties as defined by Marshall properties , index of retained strength , indirect tensile strength , permanent deformation characteristics , and fatigue resistance .A typical dense graded mixture employed in construction of surface course pavement in Iraq in accordance with SCRB specifications was used .The materials used in this study included mineral aggregate materials (coarse and fine sizes were originally obtained from Najaf Sea quarries and two grades of asphalt cements produced from Daurah refinery which are D47 and D66 . The physical properties , stiffness modulus and chemical composition are evaluated for the recovered asphalt cement from prepared asphalt mixes containing various filler types .The paper results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue life and the use of hydrated lime will decrease the moisture susceptibility of the asphalt mixtures.

  1. The Influence of Moisture on the Performance of Polymer Fibre-Reinforced Asphalt Mixture

    Directory of Open Access Journals (Sweden)

    Kamaruddin Ibrahim

    2016-01-01

    Full Text Available A number of researches have been done worldwide to evaluate the damage caused by water in bituminous pavements. The use of the retained strength ratios obtained from laboratory moisture damage tests is a useful tool in making quantitative predictions of the related damage caused by water. This study involved laboratory work on the effect of water on the performance of bituminous mixtures. Comparisons are made between the performances of Hot-rolled Asphalt (HRA bituminous mixtures containing base bitumen of 50 pen grade to that of a polymer-fibre reinforced HRA mixture. Two types of polymer fibre were studied, namely polypropylene and polyester and these fibre were added in different concentrations in the bituminous mixtures. Changes in both the cohesive properties of the bitumen and the adhesion of the bitumen to the aggregate surface were observed as a result of exposing the bituminous mixtures to moisture. The effect of polymer fibre reinforcement in bituminous mixtures helps reduce the level of moisture damage. This was evident in the lower moisture susceptibility achieved in the polymer fibre reinforced bituminous mixtures as compared to the control mixture. The additional bitumen in the fibre reinforced mixtures also afforded an increased film thickness on the aggregate particles, thus affording additional protection of the mixtures from moisture. The reinforcement of polymer fibres in bituminous mixtures also acts to decrease the moisture sensitivity of the bitumen to aggregate bonding. This may be due to the strengthening of the wetted binder matrix that helps promote both adhesion and cohesion retention.

  2. Local fluctuations in solution mixtures

    Science.gov (United States)

    Ploetz, Elizabeth A.; Smith, Paul E.

    2011-01-01

    An extension of the traditional Kirkwood-Buff (KB) theory of solutions is outlined which provides additional fluctuating quantities that can be used to characterize and probe the behavior of solution mixtures. Particle-energy and energy-energy fluctuations for local regions of any multicomponent solution are expressed in terms of experimentally obtainable quantities, thereby supplementing the usual particle-particle fluctuations provided by the established KB inversion approach. The expressions are then used to analyze experimental data for pure water over a range of temperatures and pressures, a variety of pure liquids, and three binary solution mixtures – methanol and water, benzene and methanol, and aqueous sodium chloride. In addition to providing information on local properties of solutions it is argued that the particle-energy and energy-energy fluctuations can also be used to test and refine solute and solvent force fields for use in computer simulation studies. PMID:21806137

  3. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  4. Atomistic Simulations of Bicelle Mixtures

    OpenAIRE

    Jiang, Yong; Wang, Hao; Kindt, James T.

    2010-01-01

    Mixtures of long- and short-tail phosphatidylcholine lipids are known to self-assemble into a variety of aggregates combining flat bilayerlike and curved micellelike features, commonly called bicelles. Atomistic simulations of bilayer ribbons and perforated bilayers containing dimyristoylphosphatidylcholine (DMPC, di-C14 tails) and dihexanoylphosphatidylcholine (DHPC, di-C6 tails) have been carried out to investigate the partitioning of these components between flat and curved microenvironmen...

  5. Atomistic Simulations of Bicelle Mixtures

    OpenAIRE

    Jiang, Yong; WANG, HAO; Kindt, James T.

    2010-01-01

    Mixtures of long- and short-tail phosphatidylcholine lipids are known to self-assemble into a variety of aggregates combining flat bilayerlike and curved micellelike features, commonly called bicelles. Atomistic simulations of bilayer ribbons and perforated bilayers containing dimyristoylphosphatidylcholine (DMPC, di-C14 tails) and dihexanoylphosphatidylcholine (DHPC, di-C6 tails) have been carried out to investigate the partitioning of these components between flat and curved microenvironmen...

  6. Predicting the toxicity of metal mixtures.

    Science.gov (United States)

    Balistrieri, Laurie S; Mebane, Christopher A

    2014-01-01

    The toxicity of single and multiple metal (Cd, Cu, Pb, and Zn) solutions to trout is predicted using an approach that combines calculations of: (1) solution speciation; (2) competition and accumulation of cations (H, Ca, Mg, Na, Cd, Cu, Pb, and Zn) on low abundance, high affinity and high abundance, low affinity biotic ligand sites; (3) a toxicity function that accounts for accumulation and potency of individual toxicants; and (4) biological response. The approach is evaluated by examining water composition from single metal toxicity tests of trout at 50% mortality, results of theoretical calculations of metal accumulation on fish gills and associated mortality for single, binary, ternary, and quaternary metal solutions, and predictions for a field site impacted by acid rock drainage. These evaluations indicate that toxicity of metal mixtures depends on the relative affinity and potency of toxicants for a given aquatic organism, suites of metals in the mixture, dissolved metal concentrations and ratios, and background solution composition (temperature, pH, and concentrations of major ions and dissolved organic carbon). A composite function that incorporates solution composition, affinity and competition of cations for two types of biotic ligand sites, and potencies of hydrogen and individual metals is proposed as a tool to evaluate potential toxicity of environmental solutions to trout.

  7. FRACTIONAL TRANSPORT OF SEDIMENT MIXTURES

    Institute of Scientific and Technical Information of China (English)

    Baosheng WU; Albert MOLINAS; Anping SHU

    2003-01-01

    A new method based on the Transport Capacity Fraction (TCF) concept is proposed to compute the fractional transport rates for nonuniform sediment mixtures in sand-bed channels. The TCF concept is derived from the understanding that the measurements and predictions of bed-material load are more accurate and reliable than the measurements and predictions of fractional loads. First the bed-material load is computed using an appropriate equation, then the fractional transport rates are determined by distributing the bed-material load into size groups through a transport capacity distribution function. For the computation of bed-material loads, the Aekers and White, Engelund and Hansen, and Yang equations are used in this study. Two new transport capacity distribution functions are developed for flows in sand-bed channels. The new expressions presented in this paper account for the sheltering and exposure effects that exist in mixtures. Comparisons with measured data show that the proposed method can significantly improve the predictions of fractional transport rates for nonuniform sediment mixtures.

  8. 21 CFR 82.6 - Certifiable mixtures.

    Science.gov (United States)

    2010-04-01

    ... mixture is harmless and suitable for use therein; and (3) No diluent (except resins, natural gum, pectin... mixture is for external application to shell eggs, or for use in coloring a food specified in the...

  9. Continuum thermodynamics of chemically reacting fluid mixtures

    CERN Document Server

    Bothe, Dieter

    2014-01-01

    We consider viscous and heat conducting mixtures of molecularly miscible chemical species forming a fluid in which the constituents can undergo chemical reactions. Assuming a common temperature for all components, a first main aim is the derivation of a closed system of partial mass and partial momentum balances plus a common balance of internal energy. This is achieved by careful exploitation of the entropy principle which, in particular, requires appropriate definitions of absolute temperature and chemical potentials based on an adequate definition of thermal energy that excludes diffusive contributions. The latter is crucial in order to obtain a closure framework for the interaction forces between the different species. The interaction forces split into a thermo-mechanical and a chemical part, where the former turns out to be symmetric if binary interactions are assumed. In the non-reactive case, this leads to a system of Navier-Stokes type sub-systems, coupled by interspecies friction forces. For chemical...

  10. Combinatorial bounds on the α-divergence of univariate mixture models

    KAUST Repository

    Nielsen, Frank

    2017-06-20

    We derive lower- and upper-bounds of α-divergence between univariate mixture models with components in the exponential family. Three pairs of bounds are presented in order with increasing quality and increasing computational cost. They are verified empirically through simulated Gaussian mixture models. The presented methodology generalizes to other divergence families relying on Hellinger-type integrals.

  11. Psychophysical studies of mixtures of tastants

    NARCIS (Netherlands)

    Graaf, de C.

    1988-01-01

    The human perception of mixtures of tastante was studied with reference to three central issues, i.e., 1) the paradigma of equiratio taste substance mixtures. as an instrument to manipulate the physical composition of tastant mixtures. This paradiama also enables the construction of psychophysical

  12. Fanning - A classification algorithm for mixture landscapes applied to Landsat data of Maine forests

    Science.gov (United States)

    Ungar, S. G.; Bryant, E.

    1981-01-01

    It is pointed out that typical landscapes include a relatively small number of 'pure' land cover types which combine in various proportions to form a myriad of mixture types. Most Landsat classifications algorithms used today require a separate user specification for each category, including mixture categories. Attention is given to a simpler approach, which would require the user to specify only the 'pure' types. Mixture pixels would be classified on the basis of the proportion of the area covered by each pure type within the pixel. The 'fanning' algorithm quantifies varying proportions of two 'pure' land cover types in selected mixture pixels. This algorithm was applied to 200,000 ha of forest land in Maine, taking into account a comparison with standard inventory information. Results compared well with a discrete categories classification of the same area.

  13. Effects of lubricants on binary direct compression mixtures.

    Science.gov (United States)

    Uğurlu, T; Halaçoğlu, M D; Türkoğlu, M

    2010-04-01

    The objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant on binary direct compression mixtures. Magnesium stearate (MGST), stearic acid (STAC), glyceryl behenate (COMP) and hexagonal boron nitride (HBN) were tested. The binary mixtures were 1:1 combinations of spray dried lactose (FlowLac 100), dicalcium phosphate dihydrate (Emcompress), and modified starch (Starch 1500) with microcrystalline cellulose (Avicel PH 102). Tablets were manufactured on a single-station instrumented tablet press with and without lubricants. In the case of unlubricated granules, the modified starch-microcrystalline cellulose mixture provided the highest percent compressibility value at 8.25%, spray dried lactose-microcrystalline cellulose mixture was 7.33%, and the dialcium phosphate dihydrate-microcrystalline cellulose mixture was 5.79%. Their corresponding tablet crushing strength values were: 104 N, 117 N, and 61 N, respectively. The lubricant concentrations studied were 0.5, 1, 2, and 4%. Effects of lubricant type and lubricant concentration on crushing strength were analyzed using a factorial ANOVA model. It was found that the Avicel PH 102-Starch 1500 mixture showed the highest lubricant sensitivity (110 N vs. 9 N), the least affected formulation was FlowLac-Avicel PH 102 mixture (118 N vs. 62 N). The crushing strength vs. concentration curve for MGST showed a typical biphasic profile, a fast drop up to 1% and a slower decline between 1 and 4%. The STAC, COMP, and HBN for all formulations showed a shallow linear decline of tablet crushing strength with increasing lubricant concentration. The HBN was as effective as MGST as a lubricant, and did not show a significant negative effect on the crushing strength of the tablets. The COMP and STAC also did not interfere with the crushing strength, however, they were not as effective lubricants as MGST or HBN.

  14. High-frequency sound wave propagation in binary gas mixtures flowing through microchannels

    Science.gov (United States)

    Bisi, M.; Lorenzani, S.

    2016-05-01

    The propagation of high-frequency sound waves in binary gas mixtures flowing through microchannels is investigated by using the linearized Boltzmann equation based on a Bhatnagar-Gross-Krook (BGK)-type approach and diffuse reflection boundary conditions. The results presented refer to mixtures whose constituents have comparable molecular mass (like Ne-Ar) as well as to disparate-mass gas mixtures (composed of very heavy plus very light molecules, like He-Xe). The sound wave propagation model considered in the present paper allows to analyze the precise nature of the forced-sound modes excited in different gas mixtures.

  15. Predicting toxicity of aromatic ternary mixtures to algae

    Institute of Scientific and Technical Information of China (English)

    LU GuangHua; WANG Chao; WANG PeiFang; YANG ChengZhi

    2009-01-01

    Aquatic ecosystems are often polluted with more than one type of contaminant, and information on the combined toxic effects of mixed pollutants on aquatic organisms is scarce at present. Acute toxicity of aromatic compounds and their ternary mixtures to the alga (Scenedesmus obliquus) was determined by the algae growth inhibition test. The median effective concentration (EC_(50)) value for a single aromatic compound and EC_(50mix) values for mixtures were obtained, the logarithm of n-octanol/water partition coefficient (logP_(mix)) and the frontier orbital energy gap (△E_(mix) for mixtures were calculated. Based on the quantitative structure-activity relationship model for single chemical toxicity log(1/EC_(50)) =0.426logP-1.150△E+12.61 (n=15, R~2=0.917 and Q~2=0.878), the following two-descriptor model was developed for the ternary mixture toxicity of aromatic compounds: log(1/EC_(50mix))=O.68210gP_(mix)-O.367△E_(mix)+ 4.971 (n=44, R~2-0.869 and Q~2=0.843). This model can be used to predict the combined toxicity of mixtures containing toxicants with different mechanisms of action.

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

    Science.gov (United States)

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

    2017-03-13

    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.

  17. Supercritical Water Mixture (SCWM) Experiment

    Science.gov (United States)

    Hicks, Michael C.; Hegde, Uday G.

    2012-01-01

    The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

  18. Atomistic simulations of bicelle mixtures.

    Science.gov (United States)

    Jiang, Yong; Wang, Hao; Kindt, James T

    2010-06-16

    Mixtures of long- and short-tail phosphatidylcholine lipids are known to self-assemble into a variety of aggregates combining flat bilayerlike and curved micellelike features, commonly called bicelles. Atomistic simulations of bilayer ribbons and perforated bilayers containing dimyristoylphosphatidylcholine (DMPC, di-C(14) tails) and dihexanoylphosphatidylcholine (DHPC, di-C(6) tails) have been carried out to investigate the partitioning of these components between flat and curved microenvironments and the stabilization of the bilayer edge by DHPC. To approach equilibrium partitioning of lipids on an achievable simulation timescale, configuration-bias Monte Carlo mutation moves were used to allow individual lipids to change tail length within a semigrand-canonical ensemble. Since acceptance probabilities for direct transitions between DMPC and DHPC were negligible, a third component with intermediate tail length (didecanoylphosphatidylcholine, di-C(10) tails) was included at a low concentration to serve as an intermediate for transitions between DMPC and DHPC. Strong enrichment of DHPC is seen at ribbon and pore edges, with an excess linear density of approximately 3 nm(-1). The simulation model yields estimates for the onset of edge stability with increasing bilayer DHPC content between 5% and 15% DHPC at 300 K and between 7% and 17% DHPC at 323 K, higher than experimental estimates. Local structure and composition at points of close contact between pores suggest a possible mechanism for effective attractions between pores, providing a rationalization for the tendency of bicelle mixtures to aggregate into perforated vesicles and perforated sheets.

  19. The Kinetics of Enzyme Mixtures

    Directory of Open Access Journals (Sweden)

    Simon Brown

    2014-03-01

    Full Text Available Even purified enzyme preparations are often heterogeneous. For example, preparations of aspartate aminotransferase or cytochrome oxidase can consist of several different forms of the enzyme. For this reason we consider how different the kinetics of the reactions catalysed by a mixture of forms of an enzyme must be to provide some indication of the characteristics of the species present. Based on the standard Michaelis-Menten model, we show that if the Michaelis constants (Km of two isoforms differ by a factor of at least 20 the steady-state kinetics can be used to characterise the mixture. However, even if heterogeneity is reflected in the kinetic data, the proportions of the different forms of the enzyme cannot be estimated from the kinetic data alone. Consequently, the heterogeneity of enzyme preparations is rarely reflected in measurements of their steady-state kinetics unless the species present have significantly different kinetic properties. This has two implications: (1 it is difficult, but not impossible, to detect molecular heterogeneity using kinetic data and (2 even when it is possible, a considerable quantity of high quality data is required.

  20. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    Science.gov (United States)

    2015-06-01

    EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES...protection in the United States. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR...DISTRIBUTION UNLIMITED. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES

  1. Performance Characteristic of Cold Recycled Mixture with Asphalt Emulsion and Chemical Additives

    Directory of Open Access Journals (Sweden)

    Shaowen Du

    2015-01-01

    Full Text Available Three types of chemical additives were used to modify asphalt emulsion recycled mixture. These chemical additives include composite Portland cement (CPC, hydrated lime (HL, and a combination of hydrated lime and ground-granulated blast-furnace slag (GGBF. The influence of different additives on the recycled mixture performance was investigated by volumetric and strength tests, moisture susceptibility test, rutting resistance test, and low temperature bending test. To better understand its performance characteristic, the microstructure images of the recycled mixture were observed by environmental scanning electron microscope (ESEM. Test results demonstrate that the performance improvement of the emulsion recycled mixture depends on the types and content of chemical additives. Several recommendations are presented for the selection of chemical materials. Based on ESEM image analysis, the interface bonding mechanism is proposed to explain the performance characteristic of the recycled mixture with asphalt emulsion and cementitious materials.

  2. Characteristics of The Fillers Used for Realizing the Asphalt Mixtures in Romania

    Directory of Open Access Journals (Sweden)

    Irina-Mihaela Dămiean

    2005-01-01

    Full Text Available This paper presents the lab results for four types of filler used in producing the asphalt mixture in Romania, as well as other physical-chemical characteristics of a new type of filler, derivate of the grinding of the bituminous shists through a ball mill/crusher. Knowing these physical-chemical characteristics is crucial for asphalt mixtures due to the complex purpose of the filler.

  3. A Bayesian Mixture Model for PoS Induction Using Multiple Features

    OpenAIRE

    Christodoulopoulos, Christos; Goldwater, Sharon; Steedman, Mark

    2011-01-01

    In this paper we present a fully unsupervised syntactic class induction system formulated as a Bayesian multinomial mixture model, where each word type is constrained to belong to a single class. By using a mixture model rather than a sequence model (e.g., HMM), we are able to easily add multiple kinds of features, including those at both the type level (morphology features) and token level (context and alignment features, the latter from parallel corpora). Using only context features, our sy...

  4. Afrikaner spirituality: A complex mixture

    Directory of Open Access Journals (Sweden)

    Erna Olivier

    2006-10-01

    Full Text Available The article argues that the perception that Afrikaner spirituality is and has always been founded mainly or only upon the Calvinistic tradition is a misconception. Nineteenth century Afrikaner spiritualism consisted of a mixture of theology, philosophy and a way of adapting to extreme living conditions. These factors, although with different contents, are also the determinant issues that made 21st century Afrikaner spirituality such a complex phenomenon. The article postulates that the Afrikaner nation’s current identity crisis can be resolved by closely looking at the different influences on the spirituality of the nation and by carefully guiding the people through the complex set of multiple choices to a fresh relation with Christ in a new found Christian identity to confirm our Christian foundation.

  5. Thermodiffusion in Multicomponent Mixtures Thermodynamic, Algebraic, and Neuro-Computing Models

    CERN Document Server

    Srinivasan, Seshasai

    2013-01-01

    Thermodiffusion in Multicomponent Mixtures presents the computational approaches that are employed in the study of thermodiffusion in various types of mixtures, namely, hydrocarbons, polymers, water-alcohol, molten metals, and so forth. We present a detailed formalism of these methods that are based on non-equilibrium thermodynamics or algebraic correlations or principles of the artificial neural network. The book will serve as single complete reference to understand the theoretical derivations of thermodiffusion models and its application to different types of multi-component mixtures. An exhaustive discussion of these is used to give a complete perspective of the principles and the key factors that govern the thermodiffusion process.

  6. Compactibility of mixtures of calcium carbonate and microcrystalline cellulose.

    Science.gov (United States)

    Garzón, M de Lourdes; Villafuerte, Leopoldo

    2002-01-01

    A patented coprocessed mixture of microcrystalline cellulose (MC) and calcium carbonate (CC) is claimed to perform, as a pharmaceutical excipient, equal or better than pure MC. To investigate it, the tensile strength (T) of tablets made of mixtures of MC type 102, CC, magnesium stearate (MS) and polyvinylpyrrolidone (PVP) and formed under a compaction pressure (P(c)) ranging up to 618 MPa has been determined. The compactibility of the mixtures was defined through regression parameters obtained with ln(-ln(1-T/T(max)))=slope x lnP(c) + intercept. MC/CC mixtures, P(c)=618 MPa, show a small decrease in tablet tensile strength with CC proportions up to about 20%, falling considerably thereafter. Lower compaction pressures, P(c)tablet tensile strength due to 2%-MS, P(c)=487 MPa, was recovered to 35% of its original value admixing about 25% CC. This maximal value of recovery showed a shift to lower proportions of CC, up to 10%, as compaction pressure decreased. This was attributed to lower CC-particles fragmentation or agglomerates spreading at lower compaction pressures. Mixtures with increased plasticity (MC/CC/PVP and MC/CC/PVP/MS) showed an increased compactibility, which was more evident at higher compaction pressures and higher CC proportions, presumably due to higher deformation and erosion of PVP particles. Inclusion of about 40% CC in a MC/PVP/MS mixture showed 60% recovery of the original MC tablet tensile strength. Lower MS proportions are expected to allow a higher recovery.

  7. Thermodynamic instabilities of a binary mixture of sticky hard spheres.

    Science.gov (United States)

    Fantoni, Riccardo; Gazzillo, Domenico; Giacometti, Achille

    2005-07-01

    The thermodynamic instabilities of a binary mixture of sticky hard spheres (SHS) in the modified mean spherical approximation (mMSA) and the Percus-Yevick (PY) approximation are investigated using an approach devised by Chen and Forstmann [corrected] [J. Chem. Phys. [corrected] 97, 3696 (1992)]. This scheme hinges on a diagonalization of the matrix of second functional derivatives of the grand canonical potential with respect to the particle density fluctuations. The zeroes of the smallest eigenvalue and the direction of the relative eigenvector characterize the instability uniquely. We explicitly compute three different classes of examples. For a symmetrical binary mixture, analytical calculations, both for mMSA and for PY, predict that when the strength of adhesiveness between like particles is smaller than the one between unlike particles, only a pure condensation spinodal exists; in the opposite regime, a pure demixing spinodal appears at high densities. We then compare the mMSA and PY results for a mixture where like particles interact as hard spheres (HS) and unlike particles as SHS, and for a mixture of HS in a SHS fluid. In these cases, even though the mMSA and PY spinodals are quantitatively and qualitatively very different from each other, we prove that they have the same kind of instabilities. Finally, we study the mMSA solution for five different mixtures obtained by setting the stickiness parameters equal to five different functions of the hard sphere diameters. We find that four of the five mixtures exhibit very different type of instabilities. Our results are expected to provide a further step toward a more thoughtful application of SHS models to colloidal fluids.

  8. Evaluation of Warm Mix Asphalt Additives for Use in Modified Asphalt Mixtures

    Science.gov (United States)

    Chamoun, Zahi

    The objective of this research effort is to evaluate the use of warm-mix additives with polymer modified and terminal blend tire rubber asphalt mixtures from Nevada and California. The research completed over two stages: first stage evaluated two different WMA technologies; Sasobit and Advera, and second stage evaluated one additional WMA technology; Evotherm. The experimental program covered the evaluation of resistance of the mixtures to moisture damage, the performance characteristics of the mixtures, and mechanistic analysis of mixtures in simulated pavements. In the both stages, the mixture resistance to moisture damage was evaluated using the indirect tensile test and the dynamic modulus at multiple freeze-thaw cycles, and the resistance of the various asphalt mixtures to permanent deformation using the Asphalt Mixture Performance Tester (AMPT). Resistance of the untreated mixes to fatigue cracking using the flexural beam fatigue was only completed for the first stage. One source of aggregates was sampled in, two different batches, three warm mix asphalt technologies (Advera, Sasobit and Evotherm) and three asphalt binder types (neat, polymer-modified, and terminal blend tire rubber modified asphalt binders) typically used in Nevada and California were evaluated in this study. This thesis presents the resistance of the first stage mixtures to permanent deformation and fatigue cracking using two warm-mix additives; Advera and Sasobit, and the resistance to moisture damage and permanent deformation of the second stage mixtures with only one warm-mix additive; Evotherm.

  9. Hydrothermal Synthesis, Structure Characterization and Magnetic Studies of Perovskite-type Fluorides K2NaVF6 and (NH4)aVF6

    Institute of Scientific and Technical Information of China (English)

    HE Li-jie; ZHANG Dong; FENG Shou-hua; CHEN Gang; ZOU Bo

    2012-01-01

    Two perovskite-type fluorides K2NaVF6 and (NH4)3VF6 were synthesized under mild hydrothermal conditions.The structures of the compounds were determined by means of powder X-ray diffraction analysis.The Rietveld refinement indicates that K2NaVF6 has a cubic elpasolite-type structure and crystallizes in space group Fm-3m with lattice constant a=8.3180(2) nm.(NH4)3VF6 has a cubic cryolite-type structure and crystallizes in space group Fm-3m with lattice parameter a=9.090(1) nm.The compounds were further characterized by scanning electron microscopy(SEM),thermogravimetric(TG) and differential thermal analysis(DTA).The variable temperature magnetic susceptibility of these two compounds was characterized for the first time and the result shows that the magnetic ordering is related to the crystallographic features and isolated magnetic unit with the temperature decreasing.

  10. Bayesian mixture models for spectral density estimation

    OpenAIRE

    Cadonna, Annalisa

    2017-01-01

    We introduce a novel Bayesian modeling approach to spectral density estimation for multiple time series. Considering first the case of non-stationary timeseries, the log-periodogram of each series is modeled as a mixture of Gaussiandistributions with frequency-dependent weights and mean functions. The implied model for the log-spectral density is a mixture of linear mean functionswith frequency-dependent weights. The mixture weights are built throughsuccessive differences of a logit-normal di...

  11. Thermodynamic Calculations for Complex Chemical Mixtures

    Science.gov (United States)

    Mcbride, B. J.

    1986-01-01

    General computer program, CECTRP, developed for calculation of thermodynamic properties of complex mixtures with option to calculate transport properties of these mixtures. Free-energy minimization technique used in equilibrium calculation. Rigorous equations used in transport calculations. Program calculates equilibrium compositions and corresponding thermodynamic and transport properties of mixtures. CECTRP accommodates up to 24 reactants, 20 elements, and 600 products, 400 of which are condensed. Written in FORTRAN IV for any large computer system.

  12. Hard-sphere kinetic models for inert and reactive mixtures

    Science.gov (United States)

    Polewczak, Jacek

    2016-10-01

    I consider stochastic variants of a simple reacting sphere (SRS) kinetic model (Xystris and Dahler 1978 J. Chem. Phys. 68 387-401, Qin and Dahler 1995 J. Chem. Phys. 103 725-50, Dahler and Qin 2003 J. Chem. Phys. 118 8396-404) for dense reacting mixtures. In contrast to the line-of-center models of chemical reactive models, in the SRS kinetic model, the microscopic reversibility (detailed balance) can be easily shown to be satisfied, and thus all mathematical aspects of the model can be fully justified. In the SRS model, the molecules behave as if they were single mass points with two internal states. Collisions may alter the internal states of the molecules, and this occurs when the kinetic energy associated with the reactive motion exceeds the activation energy. Reactive and non-reactive collision events are considered to be hard sphere-like. I consider a four component mixture A, B, A *, B *, in which the chemical reactions are of the type A+B\\rightleftharpoons {{A}\\ast}+{{B}\\ast} , with A * and B * being distinct species from A and B. This work extends the joined works with George Stell to the kinetic models of dense inert and reactive mixtures. The idea of introducing smearing-type effect in the collisional process results in a new class of stochastic kinetic models for both inert and reactive mixtures. In this paper the important new mathematical properties of such systems of kinetic equations are proven. The new results for stochastic revised Enskog system for inert mixtures are also provided.

  13. [Mixture Leaching Remediation Technology of Arsenic Contaminated Soil].

    Science.gov (United States)

    Chen, Xun-feng; Li, Xiao-ming; Chen, Can; Yang, Qi; Deng, Lin-jing; Xie, Wei-qiang; Zhong, Yui; Huang, Bin; Yang, Wei-qiang; Zhang, Zhi-bei

    2016-03-15

    Soil contamination of arsenic pollution has become a severely environmental issue, while soil leaching is an efficient method for remediation of arsenic-contaminated soil. In this study, batch tests were primarily conducted to select optimal mixture leaching combination. Firstly, five conventional reagents were selected and combined with each other. Secondly, the fractions were analyzed before and after the tests. Finally, to explore the feasibility of mixed leaching, three soils with different arsenic pollution levels were used to compare the leaching effect. Comparing with one-step washing, the two-step sequential washing with different reagents increased the arsenic removal efficiency. These results showed that the mixture of 4 h 0.5 mol · L⁻¹ NaOH + 4 h 0.1 mol · L⁻¹ EDTA was found to be practicable, which could enhance the removal rate of arsenic from 66.67% to 91.83%, and the concentration of arsenic in soil was decreased from 186 mg · kg⁻¹ to 15.2 mg · kg⁻¹. Furthermore, the results indicated that the distribution of fractions of arsenic in soil changed apparently after mixture leaching. Leaching process could significantly reduce the available contents of arsenic in soil. Moreover, the mixture of 0.5 mol · L⁻¹ NaOH + 0.1 mol L⁻¹ EDTA could well decrease the arsenic concentration in aluminum-type soils, while the mixture of 0.5 mol · L⁻¹ OX + 0.5 mol · L⁻¹ NaOH could well decrease the arsenic concentration in iron-type soils.

  14. Shear viscosity of liquid mixtures Mass dependence

    CERN Document Server

    Kaushal, R

    2002-01-01

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model.

  15. Empirical profile mixture models for phylogenetic reconstruction

    National Research Council Canada - National Science Library

    Si Quang, Le; Gascuel, Olivier; Lartillot, Nicolas

    2008-01-01

    Motivation: Previous studies have shown that accounting for site-specific amino acid replacement patterns using mixtures of stationary probability profiles offers a promising approach for improving...

  16. Effects of Coal—Water Mixture Properties in Atomization

    Institute of Scientific and Technical Information of China (English)

    DavidJ.Wildman; JamesM.Ekmann

    1994-01-01

    Recent suggested CWM applications include using filter cake material and mill tailings as coal sources.Neither coal type nor particle size distribution are necessarily well suited for coal-water mixture production.Slurries were prepared with and without additives and attempts were made to characterize their rheological properties and atomize these materials,Limits of operation and the value of existing rheological instrumentation and methods were investigated.Effects of changes in particle size distribution are discussed.

  17. Correlated mixtures of adiabatic and isocurvature cosmological perturbations

    CERN Document Server

    Langlois, D; Langlois, David; Riazuelo, Alain

    2000-01-01

    We examine the consequences of the existence of correlated mixtures of adiabatic and isocurvature perturbations on the CMB and large scale structure. In particular, we consider the four types of ``elementary'' totally correlated hybrid initial conditions, where only one of the four matter species (photons, baryons, neutrinos, CDM) deviates from adiabaticity. We then study the height and position of the acoustic peaks with respect to the large angular scale plateau as a function of the isocurvature to adiabatic ratio.

  18. Fractionation in Gay-Berne liquid crystal mixtures.

    Science.gov (United States)

    Moreno-Razo, J Antonio; Díaz-Herrera, Enrique; Klapp, Sabine H L

    2007-10-01

    We present a constant-pressure molecular dynamics simulation study of the phase behavior of binary (50:50) Gay-Berne liquid crystal mixtures consisting of elongated particles with different lengths (LA>LB) and equal diameters. We focus on systems at dense liquid-state conditions. Considering three mixtures characterized by different values of LA(B) and different length ratios q=LB/LA<1, we find complex fluid-fluid phase behavior resulting from the interplay between nematic, smectic-A-type, or smectic-B-type orientational ordering, on the one hand, and demixing into two phases of different composition (fractionation), on the other hand. The driving "forces" of demixing transitions are the temperature and the length ratio. Indeed, in the system characterized by the largest value of q (q=0.86) orientational order occurs already in mixed states, whereas full fractionation is found at q=0.71. The two resulting states are either of type smectic-B-nematic (intermediate temperatures) or smectic-B-smectic-B (low temperatures). In the intermediate case q=0.80 we observe a stepwise ordering and demixing behavior on cooling the system from high temperatures. Moreover, our results show that the stability range of (partially) nematic structures in mixtures of sufficiently small q can be significantly larger than in the pure counterparts, in qualitative agreement with experimental observations.

  19. Thermodynamics of mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Garcia de la Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Riesco, Nicolas [Department of Chemical Engineering, Loughborough University, Loughborough, LE113TU Leicestershire (United Kingdom)

    2008-01-30

    Mixtures with dimethyl or trimethylpyridines and alkane, aromatic compound or 1-alkanol have been examined using different theories: DISQUAC, Flory, the concentration-concentration structure factor, S{sub CC}(0), or the Kirkwood-Buff formalism. DISQUAC represents fairly well the available experimental data, and improves theoretical calculations from Dortmund UNIFAC. Two important effects have been investigated: (i) the effect of increasing the number of methyl groups attached to the aromatic ring of the amine; (ii) the effect of modifying the position of the methyl groups in this ring. The molar excess enthalpy, H{sup E}, and the molar excess volume, V{sup E}, decrease in systems with alkane or methanol as follows: pyridine > 3-methylpyridine > 3,5-dimethylpyridine and pyridine > 2-methylpyridine > 2,4-dimethylpyridine > 2,4,6-trimethylpyridine, which has been attributed to a weakening of the amine-amine interactions in the same sequences. This is in agreement with the relative variation of the effective dipole moment, {mu}-bar, and of the differences between the boiling temperature of a pyridine base and that of the homomorphic alkane. For heptane solutions, the observed H{sup E} variation, H{sup E} (3,5-dimethylpyridine) > H{sup E} (2,4-dimethylpyridine) > H{sup E} (2,6-dimethylpyridine), is explained similarly. Calculations on the basis of the Flory model confirm that orientational effects become weaker in systems with alkane in the order: pyridine > methylpyridine > dimethylpyridine > trimethylpyridine. S{sub CC}(0) calculations show that steric effects increase with the number of CH{sub 3}- groups in the pyridine base, and that the steric effects exerted by methyl groups in positions 2 and 6 are higher than when they are placed in positions 3 and 5. The hydrogen bond energy in methanol mixtures is independent of the pyridine base, and it is estimated to be -35.2 kJ mol{sup -1}. Heterocoordination in these solutions is due in part to size effects. Their

  20. Measurement of viscosity of gaseous mixtures at atmospheric pressure

    Science.gov (United States)

    Singh, J. J.; Mall, G. H.; Chegini, H.

    1986-01-01

    Coefficients of viscosity of various types of gas mixtures, including simulated natural-gas samples, have been measured at atmospheric pressure and room temperature using a modified capillary tube method. Pressure drops across the straight capillary tube section of a thermal mass flowmeter were measured for small, well-defined, volume flow rates for the test gases and for standard air. In this configuration, the flowmeter provides the volumetric flow rates as well as a well-characterized capillary section for differential pressure measurements across it. The coefficients of viscosity of the test gases were calculated using the reported value of 185.6 micro P for the viscosity of air. The coefficients of viscosity for the test mixtures were also calculated using Wilke's approximation of the Chapman-Enskog (C-E) theory. The experimental and calculated values for binary mixtures are in agreement within the reported accuracy of Wilke's approximation of the C-E theory. However, the agreement for multicomponent mixtures is less satisfactory, possible because of the limitations of Wilkes's approximation of the classical dilute-gas state model.

  1. Time-dependence in mixture toxicity prediction.

    Science.gov (United States)

    Dawson, Douglas A; Allen, Erin M G; Allen, Joshua L; Baumann, Hannah J; Bensinger, Heather M; Genco, Nicole; Guinn, Daphne; Hull, Michael W; Il'Giovine, Zachary J; Kaminski, Chelsea M; Peyton, Jennifer R; Schultz, T Wayne; Pöch, Gerald

    2014-12-04

    The value of time-dependent toxicity (TDT) data in predicting mixture toxicity was examined. Single chemical (A and B) and mixture (A+B) toxicity tests using Microtox(®) were conducted with inhibition of bioluminescence (Vibrio fischeri) being quantified after 15, 30 and 45-min of exposure. Single chemical and mixture tests for 25 sham (A1:A2) and 125 true (A:B) combinations had a minimum of seven duplicated concentrations with a duplicated control treatment for each test. Concentration/response (x/y) data were fitted to sigmoid curves using the five-parameter logistic minus one parameter (5PL-1P) function, from which slope, EC25, EC50, EC75, asymmetry, maximum effect, and r(2) values were obtained for each chemical and mixture at each exposure duration. Toxicity data were used to calculate percentage-based TDT values for each individual chemical and mixture of each combination. Predicted TDT values for each mixture were calculated by averaging the TDT values of the individual components and regressed against the observed TDT values obtained in testing, resulting in strong correlations for both sham (r(2)=0.989, n=25) and true mixtures (r(2)=0.944, n=125). Additionally, regression analyses confirmed that observed mixture TDT values calculated for the 50% effect level were somewhat better correlated with predicted mixture TDT values than at the 25 and 75% effect levels. Single chemical and mixture TDT values were classified into five levels in order to discern trends. The results suggested that the ability to predict mixture TDT by averaging the TDT of the single agents was modestly reduced when one agent of the combination had a positive TDT value and the other had a minimal or negative TDT value. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Mixture Modeling: Applications in Educational Psychology

    Science.gov (United States)

    Harring, Jeffrey R.; Hodis, Flaviu A.

    2016-01-01

    Model-based clustering methods, commonly referred to as finite mixture modeling, have been applied to a wide variety of cross-sectional and longitudinal data to account for heterogeneity in population characteristics. In this article, we elucidate 2 such approaches: growth mixture modeling and latent profile analysis. Both techniques are…

  3. Two-microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    2006-01-01

    Matlab source code for underdetermined separation of instaneous speech mixtures. The algorithm is described in [1] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: ''Two-microphone Separation of Speech Mixtures,'' 2006, submitted for journal publoication. See also, [2] Michael...

  4. Fibril assembly in whey protein mixtures

    NARCIS (Netherlands)

    Bolder, S.G.

    2007-01-01

    The objective of this thesis was to study fibril assembly in mixtures of whey proteins. The effect of the composition of the protein mixture on the structures and the resulting phase behaviour was investigated. The current work has shown that beta-lactoglobulin is responsible for the fibril assembly

  5. Evaluation of Physical Properties of Wax Mixtures Obtained From Recycling of Patterns Used in Precision Casting

    Directory of Open Access Journals (Sweden)

    Biernacki R.

    2015-04-01

    Full Text Available The study investigated the properties of selected certified mixtures used to make wax patterns for the production of precision castings for the aerospace industry. In addition, an assessment of the recycled mixtures consisting of certified wax materials recovered during autoclaving was carried out. Hardness was tested via a proposed method based on penetration, creep related deformation, bending strength and linear contraction. The hardness was studied on laboratory specimens and patterns made with the use of injection molding equipment. For these patterns, linear contraction was estimated at variable pressure and for different temperature injection parameters. Deformations connected with creep and resistance were evaluated on cylindrical specimens. Differences in creep resistance in relation to the hardness were observed depending on the type of pattern mixtures. Recycled mixture has a greater resistance and smaller linear contraction than certified mixtures used for making sprue, raisers and other parts of filler system.

  6. Supercritical separation process for complex organic mixtures

    Science.gov (United States)

    Chum, Helena L.; Filardo, Giuseppe

    1990-01-01

    A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

  7. Shear Strength Characteristics of Coir Fibre Stabilised Stone Matrix Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Bindu S

    2015-09-01

    Full Text Available The triaxial test measures the mix stability in the form of shear strength and gave better information for the prediction of field performance. The stresses acting on the laboratory specimen during the test simulate the state of stresses existing in the pavement. The Stone Matrix Asphalt mixtures (SMAwere investigated using triaxial shear strength testing at 50.8 mm/min ram rate loading at 60°C to investigate the effect of additive, coir fibre on the strength properties by varying  the percentages of fibre. SMA without fibre  is taken as the control mixture. The test was conducted at 0, 50, 75 and 100kPa confinements. The Mohr-Coulomb failure theory was used to analyze the test data and the analysis shows that the SMA stabilized mixtures had highest cohesion and shear strength as compared to the control mixture, but almost similar angle of internal friction value. The higher values of cohesion and shear strength can be associated to a fibre content of 0.3% and the percentage increase in cohesion is about 53% with respect to the control mixture. This shows that the mixture has greater resistance to shearing stresses than the control mixture. There is a trend that the strain at failure increases with increasing confinement pressure, indicating their stress dependent behaviour. The stress-strain curves indicate that the peak stress developed and the time of its occurrence is higher in stabilized mixtures when compared to those of the control mixture. For stabilized mixtures, it is observed that the shape change of the stress-strain curves is more gradual with increase in fibre content and brittle type failure does not seem to occur as in the case of control mixture.

  8. Influência do tipo de cura (selada e exposta e da imersão em água na resistência mecânica de misturas solo-RBI grade 81 com vistas a aplicações em estradas florestais Influence of the curing type (sealed and exposed and water submersion on the mechanical strength of soil-RBI grade 81 mixtures for forest roads applications

    Directory of Open Access Journals (Sweden)

    Tiago Pinto da Trindade

    2005-08-01

    Full Text Available No presente artigo, analisou-se a influência das condições de cura e da imersão em água na resistência mecânica de misturas de três solos típicos da Zona da Mata Norte de Minas Gerais, Brasil, estabilizados com o aditivo químico RBI Grade 81, para aplicações em estradas florestais. Trabalhou-se com um solo residual maduro (solo 1 e dois solos residuais jovens (solos 2 e 3 de gnaisse. O programa de ensaios de laboratório englobou: (i teores de RBI Grade 81: 2, 4 e 6% em relação ao peso de solo seco; (ii energia de compactação: Proctor Modificado; (iii parâmetros de resistência mecânica: resistência à compressão não-confinada; (iv tempo de cura dos corpos-de-prova: 7 dias em câmara climatizada; (v condições de cura dos corpos-de-prova na câmara climatizada: sem proteção e com proteção de sacos plásticos; (vi realização dos ensaios de compressão não-confinada: sem imersão e com imersão por 4 h em água. Os resultados obtidos comprovaram que: (i as condições de cura e a imersão em água dos corpos-de-prova influenciaram significativamente a resistência mecânica das misturas; (ii a selagem dos corpos-de-prova em sacos plásticos levou a se subestimar a resistência mecânica das misturas no campo; e (iii a não-imersão em água dos corpos-de-prova levou a superestimar a resistência mecânica das misturas no campo.This paper focuses on the study of the influence of the parameters curing type and water submersion on the mechanical strength of RBI Grade 81 mixtures of three typical soils from the Zona da Mata Norte de Minas Gerais, Brazil, for forest roads applications. A mature (soil 1 and two young (soils 2 and 3 gneiss residual soils were used throughout the study. Description of the laboratory testing program is as follow: (i RBI Grade 81 content: 2, 4 and 6% regarding soil dry mass; (ii compaction effort: Modified Proctor; (iii mechanical strength: non-confined compression strength; (iv mixture

  9. Toxicity of four antifouling biocides and their mixtures on the brine shrimp Artemia salina.

    Science.gov (United States)

    Koutsaftis, A; Aoyama, I

    2007-11-15

    Zinc pyrithione (ZPT), Copper pyrihione (CPT), Chlorothalonil and Diuron are four of the most widely used as alternative to tributlytin (TBT) antifouling biocides in boat paints. As most previous laboratory bioassays for these biocides have been conducted solely based on acute tests with a single compound, information on the possible combined toxicity of these common biocides to marine organisms are limited. In this study, the toxicity of binary (in several proportions), ternary and quaternary mixtures were evaluated using the brine shrimp Artemia salina as test organism. Mixture toxicities were studied using the concentration addition model (isobolograms and toxic unit summation), and the mixture toxicity index (MTI). The ZPT-CPT combination had a strictly synergistic effect which requires attention because the coexistence of ZPT and CPT in the marine environment, due to transchelation of ZPT, may occur. The binary mixtures of Diuron with the metal pyrithiones exhibited various interactive effects (synergistic, antagonistic or additive) depending on concentration ratios, whereas all binary mixtures that contained Chlorothalonil exhibited antagonistic effects. The different types of combined effects subsequent to proportion variation of binary mixtures underline the importance of the combined toxicity characterization for various ratios of concentrations. The four ternary mixtures tested, also exhibited various interactive effects, and the quaternary mixture exhibited synergism. The models applied were in agreement in most cases. The observed synergistic interactions underline the requirement to review water quality guidelines, which are likely underestimating the adverse combined effects of these chemicals.

  10. Effects of binary mixtures of inducers (toluene analogs) and of metals on bioluminescence induction of a recombinant bioreporter strain.

    Science.gov (United States)

    Kong, In Chul

    2014-10-13

    This paper investigated the effects of binary mixtures of bioluminescence inducers (toluene, xylene isomers, m-toluate) and of metals (Cu, Cd, As(III), As(V), and Cr) on bioluminescence activity of recombinant (Pm-lux) strain KG1206. Different responses and sensitivities were observed depending on the types and concentrations of mixtures of inducers or metals. In the case of inducer mixtures, antagonistic and synergistic modes of action were observed, whereas metal mixtures showed all three modes of action. Antagonistic mode of action was most common for mixtures of indirect inducers, which showed bioluminescence ranging from 29% to 62% of theoretically expected effects (P(E)). On the other hand, synergistic mode of action was observed for mixtures of direct and indirect inducers, which showed bioluminescence between 141% and 243% of P(E). In the case of binary metal mixtures, bioluminescence activities were ranged from 62% to 75% and 113% to 164% of P(E) for antagonistic and synergistic modes of action, respectively (p-values 0.0001-0.038). Therefore, mixture effects could not be generalized since they were dependent on both the types and concentrations of chemicals, suggesting that biomonitoring may constitute a better strategy by investigating types and concentrations of mixture pollutants at contaminated sites.

  11. The Use of Polyethylene in Hot Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Mohammad T. Awwad

    2007-01-01

    Full Text Available The increase in road traffic during the last two decades in combination with an insufficient degree of maintenance due to shortage in funds has caused an accelerated and continuous deterioration of the road network in Jordan. To alleviate this process, several types of measures may be effective, e.g., securing funds for maintenance, improved roadway design, use of better quality of materials and the use of more effective construction methods. The use of polymer in asphalt mixture as a modifier started in the 80s of the last century and has been tested in a number of countries around the World. In this research, polyethylene as one sort of polymers is used to investigate the potential prospects to enhance asphalt mixture properties. The objectives also include determining the best type of polyethylene to be used and its proportion. Two types of polyethylene were added to coat the aggregate [High Density Polyethylene (HDPE and Low Density Polyethylene (LDPE]. The polymers were introduced to the mixture in two states (Grinded and not Grinded. Marshall mix design was used, first to determine the optimum bitumen binder content and then further to test the modified mixture properties. In total, 105 samples were prepared (21 samples were used to determine the binder content and the remaining samples were used to investigate the effect of modifying the asphalt mixtures. The optimum asphalt content was 5.4%. Seven proportions of polyethylene of each type and state by weight of the optimum binder content were selected to be tested (6, 8, 10, 12, 14, 16 and 18%. The tests include the determination of bulk density, stability and flow. Marshall mix design requires the determination of the percentages of air voids and air voids of mineral aggregate. The results indicated that grinded HDPE polyethylene modifier provides better engineering properties. The recommended proportion of the modifier is 12% by the weight of bitumen content. It is found to increase the

  12. On the mixture model for multiphase flow

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, M.; Taivassalo, V. [VTT Energy, Espoo (Finland). Nuclear Energy; Kallio, S. [Aabo Akademi, Turku (Finland)

    1996-12-31

    Numerical flow simulation utilising a full multiphase model is impractical for a suspension possessing wide distributions in the particle size or density. Various approximations are usually made to simplify the computational task. In the simplest approach, the suspension is represented by a homogeneous single-phase system and the influence of the particles is taken into account in the values of the physical properties. This study concentrates on the derivation and closing of the model equations. The validity of the mixture model is also carefully analysed. Starting from the continuity and momentum equations written for each phase in a multiphase system, the field equations for the mixture are derived. The mixture equations largely resemble those for a single-phase flow but are represented in terms of the mixture density and velocity. The volume fraction for each dispersed phase is solved from a phase continuity equation. Various approaches applied in closing the mixture model equations are reviewed. An algebraic equation is derived for the velocity of a dispersed phase relative to the continuous phase. Simplifications made in calculating the relative velocity restrict the applicability of the mixture model to cases in which the particles reach the terminal velocity in a short time period compared to the characteristic time scale of the flow of the mixture. (75 refs.)

  13. Foaming of mixtures of pure hydrocarbons

    Science.gov (United States)

    Robinson, J. V.; Woods, W. W.

    1950-01-01

    Mixtures of pure liquid hydrocarbons are capable of foaming. Nine hydrocarbons were mixed in pairs, in all possible combinations, and four proportions of each combination. These mixtures were sealed in glass tubes, and the foaming was tested by shaking. Mixtures of aliphatic with other aliphatic hydrocarbons, or of alkyl benzenes with other alkyl benzenes, did not foam. Mixtures of aliphatic hydrocarbons with alkyl benzenes did foam. The proportions of the mixtures greatly affected the foaming, the maximum foaming of 12 of 20 pairs being at the composition 20 percent aliphatic hydrocarbon, 80 percent alkyl benzene. Six seconds was the maximum foam lifetime of any of these mixtures. Aeroshell 120 lubricating oil was fractionated into 52 fractions and a residue by extraction with acetone in a fractionating extractor. The index of refraction, foam lifetime, color, and viscosity of these fractions were measured. Low viscosity and high index fractions were extracted first. The viscosity of the fractions extracted rose and the index decreased as fractionation proceeded. Foam lifetimes and color were lowest in the middle fractions. Significance is attached to the observation that none of the foam lifetimes of the fractions or residue is as high as the foam lifetime of the original Aeroshell, indicating that the foaming is not due to a particular foaming constituent, but rather to the entire mixture.

  14. Increasing hazard rate of mixtures for natural exponential families

    CERN Document Server

    Bar-Lev, Shaul K

    2010-01-01

    Hazard rates play an important role in various areas, e.g., reliability theory, survival analysis, biostatistics, queueing theory and actuarial studies. Mixtures of distributions are also of a great preeminence in such areas as most populations of components are indeed heterogeneous. In this study we present a sufficient condition for mixtures of two elements\\ of the same natural exponential family (NEF) to have an increasing hazard rate. We then apply this condition to some classical NEF's having either quadratic, or cubic variance functions (VF) and others as well. A particular attention is devoted to the hyperbolic cosine NEF having a quadratic VF, the Ressel NEF having a cubic VF and to the Kummer distributions of type 2 NEF. The application of such a sufficient condition is quite intricate and cumbersome, in particular when applied to the latter three NEF's. Various lemmas and propositions are needed then to verify this condition for these NEF's.

  15. Sand - rubber mixtures submitted to isotropic loading: a minimal model

    Science.gov (United States)

    Platzer, Auriane; Rouhanifar, Salman; Richard, Patrick; Cazacliu, Bogdan; Ibraim, Erdin

    2017-06-01

    The volume of scrap tyres, an undesired urban waste, is increasing rapidly in every country. Mixing sand and rubber particles as a lightweight backfill is one of the possible alternatives to avoid stockpiling them in the environment. This paper presents a minimal model aiming to capture the evolution of the void ratio of sand-rubber mixtures undergoing an isotropic compression loading. It is based on the idea that, submitted to a pressure, the rubber chips deform and partially fill the porous space of the system, leading to a decrease of the void ratio with increasing pressure. Our simple approach is capable of reproducing experimental data for two types of sand (a rounded one and a sub-angular one) and up to mixtures composed of 50% of rubber.

  16. Microwave dielectric characterization of binary mixture of formamide with , -dimethylaminoethanol

    Indian Academy of Sciences (India)

    Prabhakar Undre; S N Helambe; S B Jagadale; P W Khirade; S C Mehrotra

    2007-05-01

    Dielectric relaxation measurements of formamide (FMD)–,- dimethylaminoethanol (DMAE) solvent mixtures have been carried out over the entire concentration range using time domain reflectometry technique at 25, 35 and 45° C in thefrequency range of 10 MHz to 20 GHz. The mixtures exhibit a principle dispersion of the Davidson–Cole relaxation type at microwave frequencies. Bilinear calibration method is used to obtain complex permittivity *() from complex reflection coefficient ρ*() over the frequency range of 10 MHz to 10 GHz. The excess permittivity (E), excessinverse relaxation time (1/)E, Kirkwood correlation factor (eff), activation energy and Bruggeman factor (B) are also calculated to study the solute–solvent interaction.

  17. Ultrasonic Investigations of Molecular Interaction in Binary Mixtures of Benzyl Benzoate with Acetonitrile and Benzonitrile

    Directory of Open Access Journals (Sweden)

    N. Jaya Madhuri

    2011-01-01

    Full Text Available Ultrasonic velocity, density and viscosity have been measured in the binary mixtures of benzyl benzoate with acetonitrile, benzonitrile at three temperatures 30, 40 and 50 °C. From the experimental data, thermodynamic parameters like adiabatic compressibility, internal pressure, enthalpy, activation energy etc., were computed and the molecular interactions were predicted based on the variation of excess parameters in the mixture. Also theoretical evaluation of velocities was made employing the standard theories. CFT and NOMOTO were found to have an edge. All the three mixtures have shown out strong intermolecular interactions between the unlike molecules and endothermic type of chemical reaction.

  18. Induced polarization of clay-sand mixtures. Experiments and modelling.

    Science.gov (United States)

    Okay, G.; Leroy, P.

    2012-04-01

    The complex conductivity of saturated unconsolidated sand-clay mixtures was experimentally investigated using two types of clay minerals, kaolinite and smectite (mainly Na-Montmorillonite) in the frequency range 1.4 mHz - 12 kHz. The experiments were performed with various clay contents (1, 5, 20, and 100 % in volume of the sand-clay mixture) and salinities (distilled water, 0.1 g/L, 1 g/L, and 10 g/L NaCl solution). Induced polarization measurements were performed with a cylindrical four-electrode sample-holder associated with a SIP-Fuchs II impedance meter and non-polarizing Cu/CuSO4 electrodes. The results illustrate the strong impact of the CEC of the clay minerals upon the complex conductivity. The quadrature conductivity increases steadily with the clay content. We observe that the dependence on frequency of the quadrature conductivity of sand-kaolinite mixtures is more important than for sand-bentonite mixtures. For both types of clay, the quadrature conductivity seems to be fairly independent on the pore fluid salinity except at very low clay contents. The experimental data show good agreement with predicted values given by our SIP model. This complex conductivity model considers the electrochemical polarization of the Stern layer coating the clay particles and the Maxwell-Wagner polarization. We use the differential effective medium theory to calculate the complex conductivity of the porous medium constituted of the grains and the electrolyte. The SIP model includes also the effect of the grain size distribution upon the complex conductivity spectra.

  19. Effect of Jiang Zhuo Mixture on Blood Glucose Level and Insulin Resistance in Diabetes

    Institute of Scientific and Technical Information of China (English)

    Chen Xiabo; Wang Hui

    2005-01-01

    @@ Based on the knowledge of diabetes in traditional Chinese medicine and modem biomedical sciences,Dr. Wang Hui (王晖) designed Jiang Zhuo Mixture (降浊合剂) , a preparation for treatment of fat diabetes type 2. Jiang Zhuo Mixture showed good actions of strengthening the spleen and stomach,separating the clear from the turbid, resolving the stasis and decreasing the blood glucose level. These were reported as follows.

  20. Quantiles for Finite Mixtures of Normal Distributions

    Science.gov (United States)

    Rahman, Mezbahur; Rahman, Rumanur; Pearson, Larry M.

    2006-01-01

    Quantiles for finite mixtures of normal distributions are computed. The difference between a linear combination of independent normal random variables and a linear combination of independent normal densities is emphasized. (Contains 3 tables and 1 figure.)

  1. A mixture theory for geophysical fluids

    Directory of Open Access Journals (Sweden)

    A. C. Eringen

    2004-01-01

    Full Text Available A continuum theory is developed for a geophysical fluid consisting of two species. Balance laws are given for the individual components of the mixture, modeled as micropolar viscous fluids. The continua allow independent rotational degrees of freedom, so that the fluids can exhibit couple stresses and a non-symmetric stress tensor. The second law of thermodynamics is used to develop constitutive equations. Linear constitutive equations are constituted for a heat conducting mixture, each species possessing separate viscosities. Field equations are obtained and boundary and initial conditions are stated. This theory is relevant to an atmospheric mixture consisting of any two species from rain, snow and/or sand. Also, this is a continuum theory for oceanic mixtures, such as water and silt, or water and oil spills, etc.

  2. The disentangling number for phylogenetic mixtures

    CERN Document Server

    Sullivant, Seth

    2011-01-01

    We provide a logarithmic upper bound for the disentangling number on unordered lists of leaf labeled trees. This results is useful for analyzing phylogenetic mixture models. The proof depends on interpreting multisets of trees as high dimensional contingency tables.

  3. Mapping the jamming transition of bidisperse mixtures

    Science.gov (United States)

    Koeze, D. J.; Vågberg, D.; Tjoa, B. B. T.; Tighe, B. P.

    2016-03-01

    We systematically map out the jamming transition of all 2D bidisperse mixtures of frictionless disks in the hard-particle limit. The critical volume fraction, mean coordination number, number of rattlers, structural order parameters, and bulk modulus each show a rich variation with mixture composition and particle size ratio, and can therefore be tuned by choosing certain mixtures. We identify two local minima in the critical volume fraction, both of which have low structural order; one minimum is close to the widely studied 50 : 50 mixture of particles with a ratio of radii of 1 : 1.4. We also identify a region at low size ratios characterized by increased structural order and high rattler fractions, with a corresponding enhancement in the stiffness.

  4. Ultrafiltration of a polymer-electrolyte mixture

    NARCIS (Netherlands)

    Vonk, P; Noordman, T.R; Schippers, D; Tilstra, B; Wesselingh, J.A

    1997-01-01

    We present a mathematical model to describe the ultrafiltration behaviour of polymer-electrolyte mixtures. The model combines the proper thermodynamic forces (pressure, chemical potential and electrical potential differences) with multicomponent diffusion theory. The model is verified with experimen

  5. Model structure selection in convolutive mixtures

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, Scott; Hansen, Lars Kai

    2006-01-01

    The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimoneous represent......The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimoneous...... representation in many practical mixtures. The new filter-CICAAR allows Bayesian model selection and can help answer questions like: 'Are we actually dealing with a convolutive mixture?'. We try to answer this question for EEG data....

  6. Model structure selection in convolutive mixtures

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, S.; Hansen, Lars Kai

    2006-01-01

    The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious represent......The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious...... representation in many practical mixtures. The new filter-CICAAR allows Bayesian model selection and can help answer questions like: ’Are we actually dealing with a convolutive mixture?’. We try to answer this question for EEG data....

  7. The effect of charge mixture ratio and particle size on igniter plume heat transfer characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Evans, N.A.; Brezowski, C.F.

    1990-01-01

    Investigation of the heat transfer characteristics of igniter output plumes, first reported at the Fourteenth International Pyrotechnics Seminar in 1989, has continued, using two types of igniter to determine the effect of charge mixture ratio and fuel particle size on performance. While both of these igniters had the same metallic closure disc (scored Hastelloy with a capture cone), the bridgewire sensitizer (or ignition mixture) was barium styphnate for one type, and a particular blend of fine particle titanium/potassium perchlorate ( PB'') for the other type. The output mixture for both types was titanium/potassium perchlorate; two mixture ratios (33/67 and 41/59), and two titanium particle sizes (2 and 8 {mu}m) were used. The results show that, for both types of igniter, the coarse particle size titanium produced the best performance. The overall best performance was obtained from the igniter using the PB'' ignition mixture and an output charge of 41/59 titanium/potassium perchlorate. 2 refs., 6 figs., 1 tab.

  8. Laboratory performance of asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane; Trichês, Glicério; Pais, Jorge; Pereira, Paulo; Minhoto, Manuel

    2009-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: tire rubber modified asphalt binder (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtur...

  9. Assessing sanitary mixtures in East African cities

    OpenAIRE

    Letema, S.C.

    2012-01-01

    The urbanisation of poverty and informality in East African cities poses a threat to environmental health, perpetuates social exclusion and inequalities, and creates service gaps (UN-Habitat, 2008). This makes conventional sanitation provision untenable citywide, giving rise to the emergence of sanitation mixtures. Sanitation mixtures have different scales, institutional arrangements, user groups, and rationalities for their establishment, location, and management. For assessing the performan...

  10. Fitting mixture distributions to phenylthiocarbamide (PTC) sensitivity.

    OpenAIRE

    Jones, P N; G.J. McLachlan

    1991-01-01

    A technique for fitting mixture distributions to phenylthiocarbamide (PTC) sensitivity is described. Under the assumptions of Hardy-Weinberg equilibrium, a mixture of three normal components is postulated for the observed distribution, with the mixing parameters corresponding to the proportions of the three genotypes associated with two alleles A and a acting at a single locus. The corresponding genotypes AA, Aa, and aa are then considered to have separate means and variances. This paper is c...

  11. Using Big Data Analytics to Address Mixtures Exposure

    Science.gov (United States)

    The assessment of chemical mixtures is a complex issue for regulators and health scientists. We propose that assessing chemical co-occurrence patterns and prevalence rates is a relatively simple yet powerful approach in characterizing environmental mixtures and mixtures exposure...

  12. Catalyst mixture for aromatic hydrocarbon synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Minderhoud, J.K.; Huizinga, T.; Sie, S.T.

    1989-06-06

    The present invention is concerned with catalyst mixtures consisting of two catalysts, characterized in that one, which is based on zinc, is capable of catalysing the conversion of a H/sub 2//CO mixture into oxygen-containing organic compounds, and the other is a crystalline iron/boron silicate which, after one hour's calcination in air at 500/sup 0/C, has the following properties: a certain X-ray powder diffraction pattern and, in the formula that represents the composition of the silicate, expressed in moles of the oxides, a SiO/sub 2//Fe/sub 2/O/sub 3 molar ratio that is 20-2000, a SiO/sub 2//B/sub 2/O/sub 3/ molar ratio 50-5000, and a Fe/sub 2/O/sub 3//B/sub 2/O/sub 3/ molar ratio higher than 1.0. Said catalyst mixtures show higher aromatics selectivity in the preparation of hydrocarbon mixtures from H/sub 2//CO mixtures than such a mixture comprising an iron silicate instead of the above iron/boron silicates. 3 tabs.

  13. Homogeneous cooling of mixtures of particle shapes

    Science.gov (United States)

    Hidalgo, R. C.; Serero, D.; Pöschel, T.

    2016-07-01

    In this work, we examine theoretically the cooling dynamics of binary mixtures of spheres and rods. To this end, we introduce a generalized mean field analytical theory, which describes the free cooling behavior of the mixture. The relevant characteristic time scale for the cooling process is derived, depending on the mixture composition and the aspect ratio of the rods. We simulate mixtures of spherocylinders and spheres using a molecular dynamics algorithm implemented on graphics processing unit (GPU) architecture. We systematically study mixtures composed of spheres and rods with several aspect ratios and varying the mixture composition. A homogeneous cooling state, where the time dependence of the system's intensive variables occurs only through a global granular temperature, is identified. We find cooling dynamics in excellent agreement with Haff's law, when using an adequate time scale. Using the scaling properties of the homogeneous cooling dynamics, we estimated numerically the efficiency of the energy interchange between rotational and translational degrees of freedom for collisions between spheres and rods.

  14. Study of New Type Detector for Neutron and Gamma Discrimination in Pulsed n/γMixture Field%用于脉冲n/γ混合场中n、γ甄别的新型探测器的研究

    Institute of Scientific and Technical Information of China (English)

    单卿; 贾文宝; 凌永生; 黑大千; 曾捷; 魏勇红; 张焱

    2012-01-01

    以塑料闪烁体和聚合物基复合材料为探测介质,开展用于脉冲n/γ混合场中n、γ甄别的新型探测器的研究.采用闪烁体探测器十契仑科夫探测器联合探测的方法,通过对n、γ产生的荧光和契仑科夫辐射的相关性测量,以实现n、γ的甄别,并给出脉冲中子的通量.利用蒙特卡罗方法计算了塑料闪烁体最佳厚度、n和γ在塑料闪烁体产生的次级电子能谱.同时利用模拟结果确定契仑科夫探测器探测介质的折射率,使得只有光子生成的次级电子可以在其中产生信号.%Using the plastic scintillator and polymer matrix composites material as the detecting medium, a new type detector was designed to discriminate neutron and gamma in pulsed n/y mixture field. By measuring the relationship between the fluorescence and Cherenkov lights, a detection system consisting of a plastic scintillator detector and a Cherenkov detector was used to realize the neutron and gamma discrimination. Then, the pulsed neutron flux can be obtained through the difference between the counts in scintillator and Cherenkov radiator. Monte-Carlo method was used to optimize thickness of plastic scintillator, and give the spectra of charged particles produced by the detector interacting with the neutron and gamma ray. At last, the refractive index of the polymer matrix composites was calculated to ensure that only the secondary particles of gamma ray can generate Cherenkov light.

  15. When mixtures of hard-sphere-like colloids do not behave as mixtures of hard spheres.

    Science.gov (United States)

    Germain, Ph; Malherbe, J G; Amokrane, S

    2004-10-01

    The validity of the concept of "hard-sphere-like" particles for mixtures of colloids is questioned from a theoretical point of view. This concerns the class of pseudobinary mixtures in which the nonsteric interactions between the colloids are "residual" (with very small range and moderate strength). It is shown that contrary to common expectation, such interactions may have unexpected consequences on the theoretical phase diagram. The distinction between this situation and true solute-solvent mixtures is emphasized.

  16. Fuel properties of bituminous coal and pyrolytic oil mixture

    Science.gov (United States)

    Hamdan, Hazlin; Sharuddin, Munawar Zaman; Daud, Ahmad Rafizan Mohamad; Syed-Hassan, Syed Shatir A.

    2014-10-01

    Investigation on the thermal decomposition kinetics of coal-biooil slurry (CBS) fuel prepared at different ratios (100:0,70:30,60:40,0:100) was conducted using a Thermogravimetric Analyzer (TGA). The materials consisted of Clermont bituminous coal (Australia) and bio-oil (also known as pyrolytic oil) from the source of Empty Fruit Bunch (EFB) that was thermally converted by means of pyrolysis. Thermal decomposition of CBS fuel was performed in an inert atmosphere (50mL/min nitrogen) under non-isothermal conditions from room temperature to 1000°C at heating rate of 10°C/min. The apparent activation energy (Ea.) and pre-exponential factor (A) were calculated from the experimental results by using an Arrhenius-type kinetic model which first-order decomposition reaction was assumed. All kinetic parameters were tabulated based on the TG data obtained from the experiment. It was found that, the CBS fuel has higher reactivity than Clermont coal fuel during pyrolysis process, as the addition of pyrolytic oil will reduce the Ea values of the fuel. The thermal profiles of the mixtures showed potential trends that followed the characteristics of an ideal slurry fuel where high degradation rate is desirable. Among the mixture, the optimum fuel was found at the ratio of 60:40 of pyrolytic oil/coal mixtures with highest degradation rate. These findings may contribute to the development of a slurry fuel to be used in the vast existing conventional power plants.

  17. Influence of high power ultrasound on rheological and foaming properties of model ice-cream mixtures

    Directory of Open Access Journals (Sweden)

    Verica Batur

    2010-03-01

    Full Text Available This paper presents research of the high power ultrasound effect on rheological and foaming properties of ice cream model mixtures. Ice cream model mixtures are prepared according to specific recipes, and afterward undergone through different homogenization techniques: mechanical mixing, ultrasound treatment and combination of mechanical and ultrasound treatment. Specific diameter (12.7 mm of ultrasound probe tip has been used for ultrasound treatment that lasted 5 minutes at 100 percent amplitude. Rheological parameters have been determined using rotational rheometer and expressed as flow index, consistency coefficient and apparent viscosity. From the results it can be concluded that all model mixtures have non-newtonian, dilatant type behavior. The highest viscosities have been observed for model mixtures that were homogenizes with mechanical mixing, and significantly lower values of viscosity have been observed for ultrasound treated ones. Foaming properties are expressed as percentage of increase in foam volume, foam stability index and minimal viscosity. It has been determined that ice cream model mixtures treated only with ultrasound had minimal increase in foam volume, while the highest increase in foam volume has been observed for ice cream mixture that has been treated in combination with mechanical and ultrasound treatment. Also, ice cream mixtures having higher amount of proteins in composition had shown higher foam stability. It has been determined that optimal treatment time is 10 minutes.

  18. Performance Improvement of Pulse Tube Refrigerator for Space Application with Helium-hydrogen mixture

    Science.gov (United States)

    Chen, G. B.; Yu, J. P.; Gan, Z. H.

    Weight or size of the cryocoolers used is a key factor in space applications This can be acquired by the selection of high efficiency cryocoolers or through the optimization of structural parameters. Given the type of regenerator, another way to improve the cooling performance is the adoption of gas mixture instead of pure helium as the working fluids. Gas mixtures have been proved very useful to J-T cryocoolers at 80K temperature range. In this paper, we do some theoretical and experimental study to probe into the possibility of using gas mixture to improve the coefficient of performance of regenerative cryocoolers such as pulse tube refrigerators. The performance comparison of regenerator using helium-hydrogen mixtures to pure helium gas is presented based on the analysis of the heat transfer and fluid flow. The pressure drop for helium-hydrogen mixture decreased more rapidly than the increase of thermal loss compared with pure helium, so the improvement of overall regenerator performance can be obtained. Experiments have been done with helium-hydrogen mixture in a coaxial valveless pulse tube refrigerator. Experimental results show that the cooling capacity with He-H2 mixture is 10~20 percent larger than that with pure helium, which is in coincidence with the theoretical analysis.

  19. Primary hepatocyte culture in collagen gel mixture and collagen sandwich

    Institute of Scientific and Technical Information of China (English)

    Ying-Jie Wang; Hong-Ling Liu; Hai-Tao Guo; Hong-Wei Wen; Jun Liu

    2004-01-01

    AIM: To explore the methods of hepatocytes culture in a collagen gel mixture or between double layers of collagen sandwich configuration and to examine the functional and cytomorphological characteristics of cultured hepatocytes.METHODS: A two-step collagenase perfusion technique was used to isolate the hepatocytes from Wistar rats or newborn Chinese experimental piglets. The isolated hepatocytes were cultured in a collagen gel mixture or between double layers of collagen sandwich configuration respectively. The former was that rat hepatocytes were mixed with type I rat tail collagen solution till gelled, and the medium was added onto the gel. The latter was that swine hepatocytes were seeded on a plate precoated with collagen gel for 24 h, then another layer of collagen gel was overlaid, resulting in a sandwich configuration. The cytomorphological characteristics, albumin secretion, and LDH-release of the hepatocytes cultured in these two models were examined.RESULTS: Freshly isolated rat hepatocytes were successfully mixed and fixed in collagen gel, and cultured in the gel condition. During the culture period, the urea synthesized and secreted by rat hepatocytes was detected throughout the period. Likewise, newborn experimental piglet hepatocytes were successfully fixed between the double layers of collagen gel, forming a sandwich configuration.Within a week of culture, the albumin secreted by swine hepatocytes was detected by SDS/PAGE analysis. The typical cytomorphological characteristics of the hepatocytes cultured by the above two culture models were found under a phasecontrast microscope. There was little LDH-release during the culture period.CONCLUSION: Both collagen gel mixture and double layers of collagen sandwich configuration can provide cultural conditions much closer to in vivoenvironment, and are helpful for maintaining specific hepatic fiJnctions and cytomorphological characteristics. A collagen gel mixture culture may be more eligible for the

  20. Liquid-liquid equilibria for ternary polymer mixtures

    Science.gov (United States)

    Oh, Suk Yung; Bae, Young Chan

    2011-01-01

    A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  1. Differentiation of rye and wheat flour as well as mixtures by using the kinetics of Karl Fischer water titration.

    Science.gov (United States)

    Hădărugă, Daniel I; Costescu, Corina I; Corpaş, Laura; Hădărugă, Nicoleta G; Isengard, Heinz-Dieter

    2016-03-15

    The aim of this study was to find a simple way to differentiate between rye and wheat flour and their mixtures by using the kinetic parameters of Karl Fischer water titration (KFT). Consequently, the water content and type of molecules in rye and wheat mixtures used in Romanian bread making have been investigated by means of volumetric KFT. Further, the kinetics of KFT have been determined and novel kinetic parameters corresponding to "surface" and "strongly-retained" water molecules have been identified to discriminate between rye and wheat flour and their mixtures. The "surface" and "strongly-retained" water reaction rates well correlate with the rye content in the flour mixtures, especially at higher temperature analysis (r>0.95). These parameters can be used as indicators for quality evaluation of such type of mixtures, as well as to identify adulteration by improper use of the rye-wheat flour ratios in bread making.

  2. Closed-loop liquid-liquid immiscibility in mixture of particles with spherically symmetric interaction

    Directory of Open Access Journals (Sweden)

    Yu.V. Kalyuzhnyi

    2013-01-01

    Full Text Available Thermodynamic perturbation theory for cetral-force (TPT-CF type of associating potential is used to study the phase behavior of symmetric binary mixture of associating particles with spherically symmetric interaction. The model is represented by the binary Yukawa hard-sphere mixture with additional spherically symmetric square-well associative interaction located inside the hard-core region and valid only between dissimilar species. To account for the change of the system packing fraction due to association we propose an extended version of the TPT-CF approach. In addition to already known four types of the phase diagram for binary mixtures we were able to identify the fifth type, which is characterized by the absence of the intersection of the λ-line with the liquid-vapour binodals and by the appearance of the closed- loop liquid-liquid immiscibility with upper and lower critical solution temperatures.

  3. Crack Initiation Assessment of Wearing Course Asphalt Mixtures Using Aggregate Gradation Characteristic

    Directory of Open Access Journals (Sweden)

    Dr. Iman Haryanto

    2007-05-01

    Full Text Available At normal service temperatures, wearing course asphalt mixtures may have ductile cracking. Aggregate gradation characteristic is important to avoid the premature cracking. The present study discusses a relationship between the characteristic of aggregate gradation and crack resistance of wearing course mixtures. Asphalt mixture specimens were prepared using different types of aggregate gradation. The Bailey method was employed in order to recognize the characteristic of aggregate gradations. Notched semi circular bending test was conducted to obtain the critical J integral (Jc. The coarse aggregate (CA ratio and the fine graded fine aggregate coarse (FG FAc ratio defined by the Bailey method were introduced to recognize the effect of aggregate gradation type on Jc. The result was decreasing the Jc value with increasing the CA ratio and FG FAc ratio. Satisfying the current Bailey criterion on the CA ratio for stone mastic asphalt mixtures and setting FG FAc of fine graded HMA mixtures near 0.4 seem useful in order to obtain HMA mixtures with a high Jc. The present study also discusses spherical aggregates assembly models as an aid to illustrate development of the aggregates interlocking, which influences to the cracking.

  4. On the nature of the molecular ordering of water in aqueous DMSO mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Perera, Aurélien; Mazighi, Redha [Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, 4 Place Jussieu, F75252 Paris Cedex 05 (France)

    2015-10-21

    Computer simulation studies of aqueous dimethyl sulfoxyde (DMSO) mixtures show micro-heterogeneous structures, just like aqueous alcohol mixtures. However, there is a marked difference in the aggregate structure of water between the two types of systems. While water molecules form multiconnected globular clusters in alcohols, we report herein that the typical water aggregates in aqueous DMSO mixtures are linear, favouring a 2 hydrogen bond structure per water molecule, and for all DMSO mole fractions ranging from 0.1 to 0.9. This linear-aggregate structure produces a particular signature in the water site-site structure factors, in the form of a pre-peak at k ≈ 0.2–0.8 Å{sup −1}, depending on DMSO concentration. This pre-peak is either absent in other aqueous mixtures, such as aqueous methanol mixtures, or very difficult to see through computer simulations, such as in aqueous-t-butanol mixtures. This difference in the topology of the aggregates explains why the Kirkwood-Buff integrals of aqueous-DMSO mixture look nearly ideal, in contrast with those of aqueous alcohol mixtures, suggesting a connection between the shape of the water aggregates, its fluctuations, and the concentration fluctuations. In order to further study this discrepancy between aqueous DMSO and aqueous alcohol mixture, two models of pseudo-DMSO are introduced, where the size of the sulfur atom is increased by a factor 1.6 and 1.7, respectively, hence increasing the hydrophobicity of the molecule. The study shows that these mixtures become closer to the emulsion type seen in aqueous alcohol mixtures, with more globular clustering of the water molecules, long range domain oscillations in the water-water correlations and increased water-water Kirkwood-Buff integrals. It demonstrates that the local ordering of the water molecules is influenced by the nature of the solute molecules, with very different consequences for structural properties and related thermodynamic quantities. This study

  5. Identifiability of large phylogenetic mixture models.

    Science.gov (United States)

    Rhodes, John A; Sullivant, Seth

    2012-01-01

    Phylogenetic mixture models are statistical models of character evolution allowing for heterogeneity. Each of the classes in some unknown partition of the characters may evolve by different processes, or even along different trees. Such models are of increasing interest for data analysis, as they can capture the variety of evolutionary processes that may be occurring across long sequences of DNA or proteins. The fundamental question of whether parameters of such a model are identifiable is difficult to address, due to the complexity of the parameterization. Identifiability is, however, essential to their use for statistical inference.We analyze mixture models on large trees, with many mixture components, showing that both numerical and tree parameters are indeed identifiable in these models when all trees are the same. This provides a theoretical justification for some current empirical studies, and indicates that extensions to even more mixture components should be theoretically well behaved. We also extend our results to certain mixtures on different trees, using the same algebraic techniques.

  6. Relativistic mixtures of charged and uncharged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, Gilberto M. [Departamento de Física, Universidade Federal do Paraná, Curitiba (Brazil)

    2014-01-14

    Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad’s moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick’s law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad’s distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.

  7. Microsiemens or Milligrams: Measures of Ionic Mixtures ...

    Science.gov (United States)

    In December of 2016, EPA released the Draft Field-Based Methods for Developing Aquatic Life Criteria for Specific Conductivity for public comment. Once final, states and authorized tribes may use these methods to derive field-based ecoregional ambient Aquatic Life Ambient Water Quality Criteria (AWQC) for specific conductivity (SC) in flowing waters. The methods provide flexible approaches for developing science-based SC criteria that reflect ecoregional or state specific factors. The concentration of a dissolved salt mixture can be measured in a number of ways including measurement of total dissolved solids, freezing point depression, refractive index, density, or the sum of the concentrations of individually measured ions. For the draft method, SC was selected as the measure because SC is a measure of all ions in the mixture; the measurement technology is fast, inexpensive, and accurate, and it measures only dissolved ions. When developing water quality criteria for major ions, some stakeholders may prefer to identify the ionic constituents as a measure of exposure instead of SC. A field-based method was used to derive example chronic and acute water quality criteria for SC and two anions a common mixture of ions (bicarbonate plus sulfate, [HCO3−] + [SO42−] in mg/L) that represent common mixtures in streams. These two anions are sufficient to model the ion mixture and SC (R2 = 0.94). Using [HCO3−] + [SO42−] does not imply that these two anions are the

  8. ASPECTS OF THERMODYNAMICS OF POLYMER MIXTURES

    Institute of Scientific and Technical Information of China (English)

    CHAI Zhikuan

    1987-01-01

    In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed,mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q12 plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X12 ≠ 0 and Q12 ≠ 0 the spinodals so calculated are reasonable compared to experiments.A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions.

  9. A constitutive theory of reacting electrolyte mixtures

    Science.gov (United States)

    Costa Reis, Martina; Wang, Yongqi; Bono Maurizio Sacchi Bassi, Adalberto

    2013-11-01

    A constitutive theory of reacting electrolyte mixtures is formulated. The intermolecular interactions among the constituents of the mixture are accounted for through additional freedom degrees to each constituent of the mixture. Balance equations for polar reacting continuum mixtures are accordingly formulated and a proper set of constitutive equations is derived with basis in the Müller-Liu formulation of the second law of thermodynamics. Moreover, the non-equilibrium and equilibrium responses of the reacting mixture are investigated in detail by emphasizing the inner and reactive structures of the medium. From the balance laws and constitutive relations, the effects of molecular structure of constituents upon the fluid flow are studied. It is also demonstrated that the local thermodynamic equilibrium state can be reached without imposing that the set of independent constitutive variables is time independent, neither spatially homogeneous nor null. The resulting constitutive relations presented throughout this work are of relevance to many practical applications, such as swelling of clays, developing of bio and polymeric membranes, and use of electrorheological fluids in industrial processes. The first author acknowledges financial support from National Counsel of Technological and Scientific Development (CNPq) and German Academic Exchange Service (DAAD).

  10. Asbestos Tailings as Aggregates for Asphalt Mixture

    Institute of Scientific and Technical Information of China (English)

    LIU Xinoming; XU Linrong

    2011-01-01

    To use many asbestos tailings collected in Ya-Lu highway, and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures, and properties of some asphalt mixtures were evaluated as well. X-ray diffraction (XRD), X-ray fluorescent (XRF), and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper, zinc, lead, and cadmium. Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated compared with those with basalt as aggregates.XRD and XRF measurement results infer that asbestos tailing is an excellent road material. Volume properties of AC-25 asphalt mixture with asbestos tailings satisfied the related specifications. No heavy metals and toxic pollution were detected in AAS test and the value of pH test is 8.23, which is help to the adhesion with asphalt in the asphalt concrete. When compared with basalt, high temperature property and the resistance to low temperature cracking of AC-25 asphalt mixture was improved by using asbestos tailings as aggregates. In-service AC-25 asphalt pavement with asbestos tailings also presented excellent performance and British Pendulum Number (BPN) coefficient of surface.

  11. Experimental study of two-phase filtration regimes of methane-n-pentane mixture

    Science.gov (United States)

    Zaichenko, V. M.; Molchanov, D. A.; Torchinskiy, V. M.

    2016-11-01

    The results of experimental studies of methane-n-pentane mixture filtration in a porous medium under isothermal conditions in pressure range typical for gas-condensate reservoirs are presented. Interest in the filtration problem of such mixtures is aroused by the need to intensify production of heavy fractions of gas-condensate-valuable hydrocarbons, consisting of methane and its higher homologues. Different flow regimes including oscillatory one are observed during gas-condensate extraction under natural conditions. Our studies have shown that there are multiple flow regimes including self-oscillating one under isothermal conditions for this type of mixtures depending on the initial pressure, the kind of the mixture's phase diagram and the permeability coefficients of the liquid and gas phases in the porous medium.

  12. Corrosion of stainless and carbon steels in molten mixtures of industrial nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Goods, S.H.; Bradshaw, R.W. [Sandia National Labs., Livermore, CA (United States); Prairie, M.R.; Chavez, J.M. [Sandia National Labs., Albuquerque, NM (United States)

    1994-03-01

    Corrosion behavior of two stainless steels and carbon steel in mixtures of NaNO{sub 3} and KNO{sub 3} was evaluated to determine if impurities found in commodity grades of alkali nitrates aggravate corrosivity as applicable to an advanced solar thermal energy system. Corrosion tests were conducted for 7000 hours with Types 304 and 316 stainless steels at 570C and A36 carbon steel at 316C in seven mixtures of NaNO{sub 3} and KNO{sub 3} containing variations in impurity concentrations. Corrosion tests were also conducted in a ternary mixture of NaNO{sub 3}, KNO{sub 3}, and Ca(NO{sub 3}){sub 2}. Corrosion rates were determined by descaled weight losses while oxidation products were examined by scanning electron microscopy, electron microprobe analysis, and X-ray diffraction. The nitrate mixtures were periodically analyzed for changes in impurity concentrations and for soluble corrosion products.

  13. Performance Evaluation of Stone Mastic Asphalt and Hot Mix Asphalt Mixtures Containing Recycled Concrete Aggregate

    Directory of Open Access Journals (Sweden)

    Mohammad Saeed Pourtahmasb

    2014-01-01

    Full Text Available Environmental and economic considerations have encouraged civil engineers to find ways to reuse recycled materials in new constructions. The current paper presents an experimental research on the possibility of utilizing recycled concrete aggregates (RCA in stone mastic asphalt (SMA and hot mix asphalt (HMA mixtures. Three categories of RCA in various percentages were mixed with virgin granite aggregates to produce SMA and HMA specimens. The obtained results indicated that, regardless of the RCA particular sizes, the use of RCA to replace virgin aggregates increased the needed binder content in the asphalt mixtures. Moreover, it was found that even though the volumetric and mechanical properties of the asphalt mixtures are highly affected by the sizes and percentages of the RCA but, based on the demands of the project and traffic volume, utilizing specific amounts of RCA in both types of mixtures could easily satisfy the standard requirements.

  14. Mechanical evaluation of asphalt-aggregate mixtures prepared with fly ash as a filler replacement

    Energy Technology Data Exchange (ETDEWEB)

    Tapkin, T. [Anadolu Univ., Eskisehir (Turkey). Dept. of Civil Engineering

    2008-01-15

    This paper examined methods of introducing fly ash waste products as a filler in asphalt concrete mixtures. A literature review of studies involving fly ash and asphalts was conducted. The effect of fly ash filler replacements on the mechanical properties of asphalt-aggregate mixtures was investigated. A dense bituminous calcareous aggregate was used as a reference mixture for a series of tests. Three types of fly ash were investigated, notably (1) portland cement; (2) lime; and (3) control specimens. Changes in elastic strain, elastic modulus, and permanent strain properties of the asphalt mixtures were determined through a series of fatigue tests. The behaviour of the asphalt concrete pavements were analyzed under applied loads. Results of the tests showed that the fatigue life of the fly ash specimens was higher than the calcareous aggregate specimens. It was concluded that fly ash can used as a filler replacement for dense-graded wearing courses. 35 refs., 17 tabs., 8 figs.

  15. Raman Spectroscopic Studies of Methane-Ethane Mixtures as a Function of Pressure

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2001-01-01

    Raman spectra of methane and methane-ethane mixtures (100, 85, and 49 mole % CH4) have been obtained as a function of pressure in the pressure range 0.1 to 15.3 MPaA (MPa absolute). For these mixtures methane nu (1) (symmetric C-H stretching) band positions are given as a function of pressure......; for pure methane they are in agreement with previous results. The new data on the methane nu (1) band position of ethane-containing mixtures clearly depend on the kind of molecules surrounding the vibrating methane molecule. The nu (1) band position decreases with increasing pressure; the stronger...... the dependency, the higher the content of ethane. The ethane nu (1) band position in the two mixtures showed the same kind of dependency, A qualitative explanation for this behavior is attempted, relating it to changes in van der Waals-type interactions on pressure....

  16. A cold energy mixture theory for the equation of state in solid and porous metal mixtures

    Science.gov (United States)

    Zhang, X. F.; Qiao, L.; Shi, A. S.; Zhang, J.; Guan, Z. W.

    2011-07-01

    Porous or solid multi-component mixtures are ubiquitous in nature and extensively used as industrial materials such as multifunctional energetic structural materials (MESMs), metallic and ceramic powder for shock consolidation, and porous armor materials. In order to analyze the dynamic behavior of a particular solid or porous metal mixture in any given situation, a model is developed to calculate the Hugoniot data for solid or porous mixtures using only static thermodynamic properties of the components. The model applies the cold energy mixture theory to calculate the isotherm of the components to avoid temperature effects on the mixtures. The isobaric contribution from the thermodynamic equation of state is used to describe the porous material Hugoniot. Dynamic shock responses of solid or porous powder mixtures compacted by shock waves have been analyzed based on the mixture theory and Hugoniot for porous materials. The model is tested on both single-component porous materials such as aluminum 2024, copper, and iron; and on multi-component mixtures such as W/Cu, Fe/Ni, and Al/Ni. The theoretical calculations agree well with the corresponding experimental and simulation results. The present model produces satisfactory correlation with the experimentally obtained Hugoniot data for solid porous materials over a wide pressure range.

  17. Adaptive Mixture Methods Based on Bregman Divergences

    CERN Document Server

    Donmez, Mehmet A; Kozat, Suleyman S

    2012-01-01

    We investigate adaptive mixture methods that linearly combine outputs of $m$ constituent filters running in parallel to model a desired signal. We use "Bregman divergences" and obtain certain multiplicative updates to train the linear combination weights under an affine constraint or without any constraints. We use unnormalized relative entropy and relative entropy to define two different Bregman divergences that produce an unnormalized exponentiated gradient update and a normalized exponentiated gradient update on the mixture weights, respectively. We then carry out the mean and the mean-square transient analysis of these adaptive algorithms when they are used to combine outputs of $m$ constituent filters. We illustrate the accuracy of our results and demonstrate the effectiveness of these updates for sparse mixture systems.

  18. Computer simulation of rod-sphere mixtures

    CERN Document Server

    Antypov, D

    2003-01-01

    Results are presented from a series of simulations undertaken to investigate the effect of adding small spherical particles to a fluid of rods which would otherwise represent a liquid crystalline (LC) substance. Firstly, a bulk mixture of Hard Gaussian Overlap particles with an aspect ratio of 3:1 and hard spheres with diameters equal to the breadth of the rods is simulated at various sphere concentrations. Both mixing-demixing and isotropic-nematic transition are studied using Monte Carlo techniques. Secondly, the effect of adding Lennard-Jones particles to an LC system modelled using the well established Gay-Berne potential is investigated. These rod-sphere mixtures are simulated using both the original set of interaction parameters and a modified version of the rod-sphere potential proposed in this work. The subject of interest is the internal structure of the binary mixture and its dependence on density, temperature, concentration and various parameters characterising the intermolecular interactions. Both...

  19. Quasi-chemical approximation for polyatomic mixtures

    CERN Document Server

    Dávila, M V; Matoz-Fernandez, D A; Ramirez-Pastor, A J

    2016-01-01

    The statistical thermodynamics of binary mixtures of polyatomic species was developed on a generalization in the spirit of the lattice-gas model and the quasi-chemical approximation (QCA). The new theoretical framework is obtained by combining: (i) the exact analytical expression for the partition function of non-interacting mixtures of linear $k$-mers and $l$-mers (species occupying $k$ sites and $l$ sites, respectively) adsorbed in one dimension, and its extension to higher dimensions; and (ii) a generalization of the classical QCA for multicomponent adsorbates and multisite-occupancy adsorption. The process is analyzed through the partial adsorption isotherms corresponding to both species of the mixture. Comparisons with analytical data from Bragg-Williams approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. Even though a good fitting is obtained from BWA, it is found that QCA provides a more accurate description of the phenomenon of adsorpti...

  20. Efficient radiative transfer in dust grain mixtures

    CERN Document Server

    Wolf, S

    2003-01-01

    The influence of a dust grain mixture consisting of spherical dust grains with different radii and/or chemical composition on the resulting temperature structure and spectral energy distribution of a circumstellar shell is investigated. The comparison with the results based on an approximation of dust grain parameters representing the mean optical properties of the corresponding dust grain mixture reveal that (1) the temperature dispersion of a real dust grain mixture decreases substantially with increasing optical depth, converging towards the temperature distribution resulting from the approximation of mean dust grain parameters, and (2) the resulting spectral energy distributions do not differ by more than 10% if >= 2^5 grain sizes are considered which justifies the mean parameter approximation and the many results obtained under its assumption so far. Nevertheless, the dust grain temperature dispersion at the inner boundary of a dust shell may amount to >>100K and has therefore to be considered in the cor...

  1. Two-Microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2008-01-01

    Separation of speech mixtures, often referred to as the cocktail party problem, has been studied for decades. In many source separation tasks, the separation method is limited by the assumption of at least as many sensors as sources. Further, many methods require that the number of signals within...... the recorded mixtures be known in advance. In many real-world applications, these limitations are too restrictive. We propose a novel method for underdetermined blind source separation using an instantaneous mixing model which assumes closely spaced microphones. Two source separation techniques have been...... similar signals. Using two microphones, we can separate, in principle, an arbitrary number of mixed speech signals. We show separation results for mixtures with as many as seven speech signals under instantaneous conditions. We also show that the proposed method is applicable to segregate speech signals...

  2. Mutation spectra of complex environmental mixtures

    Energy Technology Data Exchange (ETDEWEB)

    DeMarini, D.M. [EPA, Research Triangle Park, NC (United States)

    1997-10-01

    Bioassay-directed chemical analysis of complex environmental mixtures has indicated that much of the genotoxic activity of mixtures is due to the presence of one or a few classes or chemicals within the mixture. We have extended this observation to the molecular level by using colony probe hybridization and PCR/DNA sequence analysis to determine the mutation spectra of {approximately}8,000 revertants induced by a variety of complex mixtures and their chemical fractions in TA100 and TA98 of Salmonella. For urban air, >80% of mutagenic activity was due to a base/neutral fraction that contained primarily PAHs. The mutation spectrum induced by unfractionated urban air was not significantly different from that produced by a model PAH, B(a)P. The mutation spectrum induced by organic extracts of chlorinated drinking water were similar to those produced by the chlorinated furanone MX, which accounted for {approximately}20% of the mutagenic activity of the samples. The base/neutral fraction of municipal waste incinerator emissions accounted for the primary class of mutations induced by the emissions, and a polar neutral fraction accounted for the secondary class of mutations induced by the emissions. The primary class of mutations induced by cigarette smoke condensate in TA100 (GC {yields} TA) is also the primary class of mutations in the p53 gene of lung tumors of cigarette smokers. These results confirm at the molecular level that the mutations induced by a complex mixture reflect the dominance of one or a few classes of chemicals within the mixture.

  3. Landmine detection using mixture of discrete hidden Markov models

    Science.gov (United States)

    Frigui, Hichem; Hamdi, Anis; Missaoui, Oualid; Gader, Paul

    2009-05-01

    We propose a landmine detection algorithm that uses a mixture of discrete hidden Markov models. We hypothesize that the data are generated by K models. These different models reflect the fact that mines and clutter objects have different characteristics depending on the mine type, soil and weather conditions, and burial depth. Model identification could be achieved through clustering in the parameters space or in the feature space. However, this approach is inappropriate as it is not trivial to define a meaningful distance metric for model parameters or sequence comparison. Our proposed approach is based on clustering in the log-likelihood space, and has two main steps. First, one HMM is fit to each of the R individual sequence. For each fitted model, we evaluate the log-likelihood of each sequence. This will result in an R×R log-likelihood distance matrix that will be partitioned into K groups using a hierarchical clustering algorithm. In the second step, we pool the sequences, according to which cluster they belong, into K groups, and we fit one HMM to each group. The mixture of these K HMMs would be used to build a descriptive model of the data. An artificial neural networks is then used to fuse the output of the K models. Results on large and diverse Ground Penetrating Radar data collections show that the proposed method can identify meaningful and coherent HMM models that describe different properties of the data. Each HMM models a group of alarm signatures that share common attributes such as clutter, mine type, and burial depth. Our initial experiments have also indicated that the proposed mixture model outperform the baseline HMM that uses one model for the mine and one model for the background.

  4. Thermophysical Properties of Fluids and Fluid Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sengers, Jan V.; Anisimov, Mikhail A.

    2004-05-03

    The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.

  5. Paternity testing that involves a DNA mixture.

    Science.gov (United States)

    Mortera, Julia; Vecchiotti, Carla; Zoppis, Silvia; Merigioli, Sara

    2016-07-01

    Here we analyse a complex disputed paternity case, where the DNA of the putative father was extracted from his corpse that had been inhumed for over 20 years. This DNA was contaminated and appears to be a mixture of at least two individuals. Furthermore, the mother's DNA was not available. The DNA mixture was analysed so as to predict the most probable genotypes of each contributor. The major contributor's profile was then used to compute the likelihood ratio for paternity. We also show how to take into account a dropout allele and the possibility of mutation in paternity testing.

  6. Mixture Distribution Approach In Financial Risk Analysis

    OpenAIRE

    Kocak, Keziban; Calis, Nazif; Unal, Deniz

    2014-01-01

    In recent years, major changes occurred in the prices of stock exchange appeared the necessity of measuring the financial risk. Nowadays, Value-atRisk (VaR) is often used to calculate the financial risk. Parametric methods which need normality are mostly used in the calculation of VaR.If the financial data does not fit the normal distribution, mixture of normal distribution models can be fitted to this data. In this study, the financial risk is calculated by using normal mixture distribution ...

  7. Boiler derating for coal-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Horney, F.A.; Nolte, F.S.

    1983-11-01

    The authors demonstrated a method for approximating the derating required when converting an oil or natural gas fired unit to a coal-water mixture. If the results show that a retrofit to coal-water mixture appears economically reasonable, then a more detailed analysis should be made by the boiler manufacturer whose methods are more precise than the methods of this paper. The expense of having the boiler manufacturer make a precise analysis can be avoided if the results of the analysis of this paper show conversion not to be viable.

  8. Conditional Density Approximations with Mixtures of Polynomials

    DEFF Research Database (Denmark)

    Varando, Gherardo; López-Cruz, Pedro L.; Nielsen, Thomas Dyhre

    2015-01-01

    Mixtures of polynomials (MoPs) are a non-parametric density estimation technique especially designed for hybrid Bayesian networks with continuous and discrete variables. Algorithms to learn one- and multi-dimensional (marginal) MoPs from data have recently been proposed. In this paper we introduce...... is found. We illustrate and study the methods using data sampled from known parametric distributions, and we demonstrate their applicability by learning models based on real neuroscience data. Finally, we compare the performance of the proposed methods with an approach for learning mixtures of truncated...

  9. Flows and chemical reactions in homogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2013-01-01

    Flows with chemical reactions can occur in various fields such as combustion, process engineering, aeronautics, the atmospheric environment and aquatics. The examples of application chosen in this book mainly concern homogeneous reactive mixtures that can occur in propellers within the fields of process engineering and combustion: - propagation of sound and monodimensional flows in nozzles, which may include disequilibria of the internal modes of the energy of molecules; - ideal chemical reactors, stabilization of their steady operation points in the homogeneous case of a perfect mixture and c

  10. Mixture for removing tar and paraffin deposits

    Energy Technology Data Exchange (ETDEWEB)

    kamenshchikov, F.A.; Frolov, M.A.; Golovin, I.N.; Khusainov, Z.M.; Smirnov, Ya.L.; Suchkov, B.M.

    1981-05-23

    Mixture is claimed for removing tar and paraffin deposits (TPD) on the basis of the butyl-benzene fraction (BBF), which is intended to more efficiently remove TPD from the surface of refinery equipment, additionally has piperylene, isoprene and isoamine with the following ratio of the components: piperylene, 19-31%; isoprene, 8-12%; isoamines, 8-12%, while BBF, the rest. The efficiency of the given compositions was assessed by the rate at which the plates were cleaned of TPD and pure commercial paraffin. It has been shown that BBF dissolves 4-6 times faster in the given mixture than in BBF and pyperylene.

  11. Viscosity of oil and water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, A.E.; Hall, A.R.W. [National Engineering Laboratory, Glasgow (United Kingdom)

    1999-07-01

    A study was performed to investigate the apparent viscosity of oil and water mixtures using the pressure loss along a horizontal pipe. Water fractions between 100% to 5% were examined at three flow velocities and three temperatures. Four combinations of crude oil and saline solution were used. Tests found that the mixture viscosity exhibited a peak at the position of phase inversion. The value of this maximum viscosity depended upon the temperature and fluid combination used, but not the velocity. Physical properties of the fluids were important factors in the viscosity/water fraction behaviour. (author)

  12. Particle segregation during explosive dispersal of binary particle mixtures

    Science.gov (United States)

    Frost, David L.; Loiseau, Jason; Marr, Bradley J.; Goroshin, Samuel

    2017-01-01

    The explosive dispersal of a layer of solid particles surrounding a spherical high explosive charge generates a turbulent, multiphase flow. The shock-compacted particle layer typically fractures into discrete fragments which move radially outwards on ballistic trajectories. The fragments shed particles in their wakes forming jet-like structures. The tendency to form jets depends on the mass-ratio of the particles to explosive and the type of particles. Brittle or soft, ductile particles are more susceptible to forming jets during compaction and dispersal, whereas particles that are comprised of material with moderate hardness, high compressive strength and high toughness are much less prone to forming jets. Experiments have been carried out to determine the degree of particle segregation that occurs during the explosive dispersal of a uniform, binary mixture containing both "jetting" (silicon carbide) and "non-jetting" (steel) particles with various mass fractions of each particle type. During the dispersal of mixtures that contain predominantly non-jetting (steel) particles, the steel particles form a stable layer whereas the jetting (silicon carbide) particles rapidly segregate and form jets which are confined within the shell of steel particles. As the fraction of silicon carbide particles increases, the jet structures dominate the particle motion and the steel particles are entrained into the jet structures.

  13. Physical properties and bioactive constituents of powdered mixtures and drinks prepared with cocoa and various sweeteners.

    Science.gov (United States)

    Belscak-Cvitanović, Ana; Benković, Maja; Komes, Drazenka; Bauman, Ingrid; Horzić, Dunja; Dujmić, Filip; Matijasec, Matea

    2010-06-23

    In the present study the physical properties of powdered cocoa drink mixtures prepared from two cocoa powders with various fat contents and different sweeteners, as well as the bioactive content and sensory properties of cocoa drinks prepared from them, were investigated. Particle size and bulk density of the used sugars and sweeteners, as well as the formulated mixtures, were determined and their influence on cohesion index was evaluated. To compare the content of polyphenols in the formulated cocoa drink mixtures, UV-vis spectrophotometric methods were applied. Antioxidant capacity of cocoa drinks was evaluated by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing/antioxidant power (FRAP) assays. The analyzed cocoa drinks prepared from cocoa powder and different sugars or sweeteners delivered a substantial content of cocoa antioxidants, whereas the content and the type of sugar or sweetener did not affect the polyphenolic constituents of the prepared cocoa mixtures. Cocoa powder mixtures prepared with the cocoa powder containing higher fat content (16-18%) generally provided lower total polyphenol, total flavonoid, flavan-3-ol, and proanthocyanidin contents, compared to the mixtures prepared with cocoa containing lower fat content (10-12%). Total phenol content of cocoa drinks prepared from experimental mixtures ranged from 320.45 to 480.45 mg of GAE/L, whereas the ranking of the antioxidant capacities varied depending on the used assay, and the fat content of cocoa powder did not affect the antioxidant capacity of cocoa mixtures. As determined, the addition of sugar to cocoa powder increases the solubility and dispersibility of the mixtures; on the basis of their cohesion index all mixtures can be classified as very cohesive or hardened/extremely cohesive. Results of the sensory evaluation, using the 9-point hedonic scale, showed that there was a preference for the cocoa drinks made

  14. Achieving Mixtures of Ultra-High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Mircea POPA

    2013-07-01

    Full Text Available Ultra-High Performance Concrete (UHPC is a relatively new concrete. According to [11] UHPC is that concrete which features compressive strength over C100/115 class. Up to this point standards for this type of concrete were not adopted, although its characteristic strength exceeds those specified in [33]. Its main property is high compressive strength. This provides the possibility of reducing the section of elements (beams or columns made of this type of concrete, while the load capacity remains high. The study consists in blending mixtures of UHPC made of varying proportions of materials. The authors have obtained strengths of up to 160 MPa. The materials used are: Portland cement, silica fume, quartz powder, steel fibers, superplasticiser, sand and crushed aggregate for concrete - andesite.

  15. Phase behaviour of deionized binary mixtures of charged colloidal spheres.

    Science.gov (United States)

    Lorenz, Nina J; Schöpe, Hans Joachim; Reiber, Holger; Palberg, Thomas; Wette, Patrick; Klassen, Ina; Holland-Moritz, Dirk; Herlach, Dieter; Okubo, Tsuneo

    2009-11-18

    We review recent work on the phase behaviour of binary charged sphere mixtures as a function of particle concentration and composition. Both size ratios Γ and charge ratios Λ are varied over a wide range. Unlike the case for hard spheres, the long-ranged Coulomb interaction stabilizes the crystal phase at low particle concentrations and shifts the occurrence of amorphous solids to particle concentrations considerably larger than the freezing concentration. Depending on Γ and Λ, we observe upper azeotrope, spindle, lower azeotrope and eutectic types of phase diagrams, all known well from metal systems. Most solids are of body centred cubic structure. Occasionally stoichiometric compounds are formed at large particle concentrations. For very low Γ, entropic effects dominate and induce a fluid-fluid phase separation. Since for charged spheres the charge ratio Λ is also decisive for the type of phase diagram, future experiments with charge variable silica spheres are suggested.

  16. Using of Local Limestone as Aggregate in Concrete Mixture

    Directory of Open Access Journals (Sweden)

    Dr.Muyasser M. Jomaa'h

    2012-03-01

    Full Text Available This research deals with the field investigations and construction properties for using limestone as a lightweight course aggregate in concrete mixture in stead of normal coarse aggregate. Concrete cubes samples have been prepared with dimensions of 150*150*150 mm according to ASTM. For these samples the normal coarse aggregate was replaced by 100% coarse crushed limestone. Three types of limestone which were used (Al-Sinea, Makhool and Himreen, it was found that the Al-Sinea type of limestone gave a good combination (fcu =32.11MPa without admixtures. The obtained results showed a suitable reduction in dead loads of structural elements and cost. Accordingly, the usage of limestone will improve the structural applications and concrete mix properties to attain economic viability. These above results make limestone as a good alternative of normal coarse aggregate

  17. MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

    Directory of Open Access Journals (Sweden)

    Shu-Chuan Chen

    Full Text Available The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process.

  18. MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

    Science.gov (United States)

    Chen, Shu-Chuan; Ogata, Aaron

    2015-01-01

    The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process.

  19. A Skew-Normal Mixture Regression Model

    Science.gov (United States)

    Liu, Min; Lin, Tsung-I

    2014-01-01

    A challenge associated with traditional mixture regression models (MRMs), which rest on the assumption of normally distributed errors, is determining the number of unobserved groups. Specifically, even slight deviations from normality can lead to the detection of spurious classes. The current work aims to (a) examine how sensitive the commonly…

  20. Uniform design of experiments with mixtures

    Institute of Scientific and Technical Information of China (English)

    王元; 方开泰

    1996-01-01

    Consider a design of experiments with mixtures:0≤ai

  1. Modeling text with generalizable Gaussian mixtures

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Sigurdsson, Sigurdur; Kolenda, Thomas

    2000-01-01

    We apply and discuss generalizable Gaussian mixture (GGM) models for text mining. The model automatically adapts model complexity for a given text representation. We show that the generalizability of these models depends on the dimensionality of the representation and the sample size. We discuss...

  2. The Coffee-Milk Mixture Problem Revisited

    Science.gov (United States)

    Marion, Charles F.

    2015-01-01

    This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put…

  3. Quantification of complex mixtures by NMR

    NARCIS (Netherlands)

    Duynhoven, van J.P.M.; Velzen, van E.; Jacobs, D.M.

    2013-01-01

    NMR has firmly established itself as an analytical tool that can quantify analyte concentrations in complex mixtures in a rapid, cost-effective, accurate and precise manner. Here, the technological advances with respect to instrumentation, sample preparation, data acquisition and data processing ove

  4. Toxicology of chemical mixtures: International perspective

    NARCIS (Netherlands)

    Feron, V.J.; Cassee, F.R.; Groten, J.P.

    1998-01-01

    This paper reviews major activities outside the United States on human health issues related to chemical mixtures. In Europe an international study group on combination effects has been formed and has started by defining synergism and antagonism. Successful research programs in Europe include the de

  5. Mixture toxicity of PBT-like chemicals

    DEFF Research Database (Denmark)

    Syberg, Kristian; Dai, Lina; Ramskov, Tina

    beyond that of the individual components. Firstly, the effects of three chemicals with PBT-like properties (acetyl cedrene, pyrene and triclosan) was examined on the freshwater snail, Potamopyrgus antipodarum. Secondly, mixture bioaccumulation of the same three chemicals were assessed experimentally...

  6. Concrete mixture characterization. Cementitious barriers partnership

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Protiere, Yannick [SIMCO Technologies, Inc., Quebec (Canada)

    2014-12-01

    This report summarizes the characterization study performed on two concrete mixtures used for radioactive waste storage. Both mixtures were prepared with approximately 425 kg of binder. The testing protocol mostly focused on determining the transport properties of the mixtures; volume of permeable voids (porosity), diffusion coefficients, and water permeability were evaluated. Tests were performed after different curing durations. In order to obtain data on the statistical distribution of transport properties, the measurements after 2 years of curing were performed on 10+ samples. Overall, both mixtures exhibited very low tortuosities and permeabilities, a direct consequence of their low water-to-binder ratio and the use of supplementary cementitious materials. The data generated on 2-year old samples showed that porosity, tortuosity and permeability follow a normal distribution. Chloride ponding tests were also performed on test samples. They showed limited chloride ingress, in line with measured transport properties. These test results also showed that both materials react differently with chloride, a consequence of the differences in the binder chemical compositions.

  7. Predicting diffusivities in dense fluid mixtures

    Directory of Open Access Journals (Sweden)

    C. DARIVA

    1999-09-01

    Full Text Available In this work the Enskog solution of the Boltzmann equation, as corrected by Speedy, together with the Weeks-Chandler-Andersen (WCA perturbation theory of liquids is employed in correlating and predicting self-diffusivities of dense fluids. Afterwards this theory is used to estimate mutual diffusion coefficients of solutes at infinite dilution in sub and supercritical solvents. We have also investigated the behavior of Fick diffusion coefficients in the proximity of a binary vapor-liquid critical point since this subject is of great interest for extraction purposes. The approach presented here, which makes use of a density and temperature dependent hard-sphere diameter, is shown to be excellent for predicting diffusivities in dense pure fluids and fluid mixtures. The calculations involved highly nonideal mixtures as well as systems with high molecular asymmetry. The predicted diffusivities are in good agreement with the experimental data for the pure and binary systems. The methodology proposed here makes only use of pure component information and density of mixtures. The simple algebraic relations are proposed without any binary adjustable parameters and can be readily used for estimating diffusivities in multicomponent mixtures.

  8. Self-assembly models for lipid mixtures

    Science.gov (United States)

    Singh, Divya; Porcar, Lionel; Butler, Paul; Perez-Salas, Ursula

    2006-03-01

    Solutions of mixed long and short (detergent-like) phospholipids referred to as ``bicelle'' mixtures in the literature, are known to form a variety of different morphologies based on their total lipid composition and temperature in a complex phase diagram. Some of these morphologies have been found to orient in a magnetic field, and consequently bicelle mixtures are widely used to study the structure of soluble as well as membrane embedded proteins using NMR. In this work, we report on the low temperature phase of the DMPC and DHPC bicelle mixture, where there is agreement on the discoid structures but where molecular packing models are still being contested. The most widely accepted packing arrangement, first proposed by Vold and Prosser had the lipids completely segregated in the disk: DHPC in the rim and DMPC in the disk. Using data from small angle neutron scattering (SANS) experiments, we show how radius of the planar domain of the disks is governed by the effective molar ratio qeff of lipids in aggregate and not the molar ratio q (q = [DMPC]/[DHPC] ) as has been understood previously. We propose a new quantitative (packing) model and show that in this self assembly scheme, qeff is the real determinant of disk sizes. Based on qeff , a master equation can then scale the radii of disks from mixtures with varying q and total lipid concentration.

  9. Flexible Rasch Mixture Models with Package psychomix

    Directory of Open Access Journals (Sweden)

    Hannah Frick

    2012-05-01

    Full Text Available Measurement invariance is an important assumption in the Rasch model and mixture models constitute a flexible way of checking for a violation of this assumption by detecting unobserved heterogeneity in item response data. Here, a general class of Rasch mixture models is established and implemented in R, using conditional maximum likelihood estimation of the item parameters (given the raw scores along with flexible specification of two model building blocks: (1 Mixture weights for the unobserved classes can be treated as model parameters or based on covariates in a concomitant variable model. (2 The distribution of raw score probabilities can be parametrized in two possible ways, either using a saturated model or a specification through mean and variance. The function raschmix( in the R package psychomix provides these models, leveraging the general infrastructure for fitting mixture models in the flexmix package. Usage of the function and its associated methods is illustrated on artificial data as well as empirical data from a study of verbally aggressive behavior.

  10. Spinodal decomposition of chemically reactive binary mixtures

    Science.gov (United States)

    Lamorgese, A.; Mauri, R.

    2016-08-01

    We simulate the influence of a reversible isomerization reaction on the phase segregation process occurring after spinodal decomposition of a deeply quenched regular binary mixture, restricting attention to systems wherein material transport occurs solely by diffusion. Our theoretical approach follows a diffuse-interface model of partially miscible binary mixtures wherein the coupling between reaction and diffusion is addressed within the frame of nonequilibrium thermodynamics, leading to a linear dependence of the reaction rate on the chemical affinity. Ultimately, the rate for an elementary reaction depends on the local part of the chemical potential difference since reaction is an inherently local phenomenon. Based on two-dimensional simulation results, we express the competition between segregation and reaction as a function of the Damköhler number. For a phase-separating mixture with components having different physical properties, a skewed phase diagram leads, at large times, to a system converging to a single-phase equilibrium state, corresponding to the absolute minimum of the Gibbs free energy. This conclusion continues to hold for the critical phase separation of an ideally perfectly symmetric binary mixture, where the choice of final equilibrium state at large times depends on the initial mean concentration being slightly larger or less than the critical concentration.

  11. Toxicity of metal mixtures to chick embryos

    Energy Technology Data Exchange (ETDEWEB)

    Birge, W.J.; Roberts, O.W.; Black, J.A.

    1976-09-01

    The toxic effects of mercury/selenium and certain other metal mixtures on the chick embryo are examined to determine whether antagonistic, additive or synergistic interactions occur. White Plymouth Rock chicken eggs were treated by yolk injection with cadmium chloride, mercuric chloride, zinc chloride and sodium selenate. Test aliquots were injected prior to incubation using the needle track procedure. Using a sample size of 200, percent survival was determined as hatchability of experimental eggs/controls. Metal mixtures used included mercury/cadmium, mercury/selenium, mercury/zinc, cadmium/selenium, and cadmium/zinc. Except for mercury/selenium, all other metal mixtures gave actual values that were within 5% of those for additive toxic effects. Actual hatchability frequencies for test concentrations of mercury/selenium indicated a moderate degree of synergism. Results indicate that the strong mercury/selenium synergism which affects embryonic development in the carp does not apply for the chick embryo; that most two-way combinations of cadmium, mercury, selenium and zinc exert purely additive effects on chick hatchability; and that these metal mixtures give no discernible antagonistic interactions which affect survival of chick embryos. (MFB)

  12. Using Regression Mixture Analysis in Educational Research

    Directory of Open Access Journals (Sweden)

    Cody S. Ding

    2006-11-01

    Full Text Available Conventional regression analysis is typically used in educational research. Usually such an analysis implicitly assumes that a common set of regression parameter estimates captures the population characteristics represented in the sample. In some situations, however, this implicit assumption may not be realistic, and the sample may contain several subpopulations such as high math achievers and low math achievers. In these cases, conventional regression models may provide biased estimates since the parameter estimates are constrained to be the same across subpopulations. This paper advocates the applications of regression mixture models, also known as latent class regression analysis, in educational research. Regression mixture analysis is more flexible than conventional regression analysis in that latent classes in the data can be identified and regression parameter estimates can vary within each latent class. An illustration of regression mixture analysis is provided based on a dataset of authentic data. The strengths and limitations of the regression mixture models are discussed in the context of educational research.

  13. Two-microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    2006-01-01

    of Speech Mixtures," 2006, submited for journal publication. See also, [2] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: "Overcomplete Blind Source Separation by Combining ICA and Binary Time-Frequency Masking," in proceedings of IEEE International workshop on Machine Learning...

  14. Structure of cholesterol/ceramide monolayer mixtures

    DEFF Research Database (Denmark)

    Scheffer, L.; Solomonov, I.; Weygand, M.J.

    2005-01-01

    The structure of monolayers of cholesterol/ ceramide mixtures was investigated using grazing incidence x-ray diffraction, immunofluorescence, and atomic force microscopy techniques. Grazing incidence x-ray diffraction measurements showed the existence of a crystalline mixed phase of the two...

  15. Mixture model analysis of complex samples

    NARCIS (Netherlands)

    Wedel, M; ter Hofstede, F; Steenkamp, JBEM

    1998-01-01

    We investigate the effects of a complex sampling design on the estimation of mixture models. An approximate or pseudo likelihood approach is proposed to obtain consistent estimates of class-specific parameters when the sample arises from such a complex design. The effects of ignoring the sample desi

  16. Numerical Solution of Hard-Core Mixtures

    OpenAIRE

    Buhot, Arnaud; Krauth, Werner

    1997-01-01

    We study the equilibrium phase diagram of binary mixtures of hard spheres as well as of parallel hard cubes. A superior cluster algorithm allows us to establish and to access the demixed phase for both systems and to investigate the subtle interplay between short-range depletion and long-range demixing.

  17. Pool Boiling of Hydrocarbon Mixtures on Water

    Energy Technology Data Exchange (ETDEWEB)

    Boee, R.

    1996-09-01

    In maritime transport of liquefied natural gas (LNG) there is a risk of spilling cryogenic liquid onto water. The present doctoral thesis discusses transient boiling experiments in which liquid hydrocarbons were poured onto water and left to boil off. Composition changes during boiling are believed to be connected with the initiation of rapid phase transition in LNG spilled on water. 64 experimental runs were carried out, 14 using pure liquid methane, 36 using methane-ethane, and 14 using methane-propane binary mixtures of different composition. The water surface was open to the atmosphere and covered an area of 200 cm{sup 2} at 25 - 40{sup o}C. The heat flux was obtained by monitoring the change of mass vs time. The void fraction in the boiling layer was measured with a gamma densitometer, and a method for adapting this measurement concept to the case of a boiling cryogenic liquid mixture is suggested. Significant differences in the boil-off characteristics between pure methane and binary mixtures revealed by previous studies are confirmed. Pure methane is in film boiling, whereas the mixtures appear to enter the transitional boiling regime with only small amounts of the second component added. The results indicate that the common assumption that LNG will be in film boiling on water because of the high temperature difference, may be questioned. Comparison with previous work shows that at this small scale the results are influenced by the experimental apparatus and procedures. 66 refs., 76 figs., 28 tabs.

  18. Mixtures of Ultracold Fermions with Unequal Masses

    Science.gov (United States)

    de Melo, Carlos A. R. Sa

    2008-05-01

    The quantum phases of ultracold fermions with unequal masses are discussed in continuum and lattice models for a wide variety of mixtures which exhibit Feshbach resonances, e.g., mixtures of ^6Li and ^40K. The evolution of superfluidity from the Bardeen-Cooper-Schrieffer (BCS) to the Bose-Einstein condensation (BEC) regime in the continuum is analyzed as a function of scattering parameter, population imbalance and mass anisotropy. In the continuum case, regions corresponding to normal, phase-separated or coexisting uniform-superfluid/excess-fermion phases are identified and the possibility of topological phase transitions is discussed [1]. For optical lattices, the phase diagrams as a function of interaction strength, population imbalance, filling fraction and tunneling parameters are presented [2]. In addition to the characteristic phases of the continuum, a series of insulating phases emerge in the phase diagrams of optical lattices, including a Bose-Mott insulator (BMI), a Fermi-Pauli insulator (FPI), a phase-separated BMI/FPI mixture, and a Bose-Fermi checkerboard (BFC) phase. Lastly, the effects of harmonic traps and the emergence of unusual shell structures are discussed for mixtures of fermions with unequal masses. [1] M. Iskin, and C. A. R. S' a de Melo, Phys. Rev. Lett 97, 100404 (2006); [2] M. Iskin, and C. A. R. S' a de Melo, Phys. Rev. Lett. 99, 080403 (2007).

  19. Cementitious barriers partnership concrete mixture characterization

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Protiere, Yannick [SIMCO Technologies, Inc., Quebec (Canada)

    2014-12-01

    This report summarizes the characterization study performed on two concrete mixtures used for radioactive waste storage. Both mixtures were prepared with approximately 425 kg of binder. The testing protocol mostly focused on determining the transport properties of the mixtures; volume of permeable voids (porosity), diffusion coefficients, and water permeability were evaluated. Tests were performed after different curing durations. In order to obtain data on the statistical distribution of transport properties, the measurements after 2 years of curing were performed on 10+ samples. Overall, both mixtures exhibited very low tortuosities and permeabilities, a direct consequence of their low water-to-binder ratio and the use of supplementary cementitious materials. The data generated on 2-year old samples showed that porosity, tortuosity and permeability follow a normal distribution. Chloride ponding tests were also performed on test samples. They showed limited chloride ingress, in line with measured transport properties. These test results also showed that both materials react differently with chloride, a consequence of the differences in the binder chemical compositions.

  20. Some aspects of symmetric Gamma process mixtures

    OpenAIRE

    Naulet, Zacharie; Barat, Eric

    2015-01-01

    In this article, we present some specific aspects of symmetric Gamma process mixtures for use in regression models. We propose a new Gibbs sampler for simulating the posterior and we establish adaptive posterior rates of convergence related to the Gaussian mean regression problem.

  1. The Coffee-Milk Mixture Problem Revisited

    Science.gov (United States)

    Marion, Charles F.

    2015-01-01

    This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put…

  2. Theory of dynamic arrest in colloidal mixtures.

    Science.gov (United States)

    Juárez-Maldonado, R; Medina-Noyola, M

    2008-05-01

    We present a first-principles theory of dynamic arrest in colloidal mixtures based on the multicomponent self-consistent generalized Langevin equation theory of colloid dynamics [M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E 72, 031107 (2005); M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E76, 039902 (2007)]. We illustrate its application with a description of dynamic arrest in two simple model colloidal mixtures: namely, hard-sphere and repulsive Yukawa binary mixtures. Our results include observation of the two patterns of dynamic arrest, one in which both species become simultaneously arrested and the other involving the sequential arrest of the two species. The latter case gives rise to mixed states in which one species is arrested while the other species remains mobile. We also derive the ("bifurcation" or fixed-point") equations for the nonergodic parameters of the system, which takes the surprisingly simple form of a system of coupled equations for the localization length of the particles of each species. The solution of this system of equations indicates unambiguously which species is arrested (finite localization length) and which species remains ergodic (infinite localization length). As a result, we are able to draw the entire ergodic-nonergodic phase diagram of the binary hard-sphere mixture.

  3. Toxicology of chemical mixtures: International perspective

    NARCIS (Netherlands)

    Feron, V.J.; Cassee, F.R.; Groten, J.P.

    1998-01-01

    This paper reviews major activities outside the United States on human health issues related to chemical mixtures. In Europe an international study group on combination effects has been formed and has started by defining synergism and antagonism. Successful research programs in Europe include the

  4. Experiments with Mixtures Designs, Models, and the Analysis of Mixture Data

    CERN Document Server

    Cornell, John A

    2011-01-01

    The most comprehensive, single-volume guide to conducting experiments with mixtures"If one is involved, or heavily interested, in experiments on mixtures of ingredients, one must obtain this book. It is, as was the first edition, the definitive work."-Short Book Reviews (Publication of the International Statistical Institute)"The text contains many examples with worked solutions and with its extensive coverage of the subject matter will prove invaluable to those in the industrial and educational sectors whose work involves the design and analysis of mixture experiments."-Journal of the Royal S

  5. The pH Value of Fungicide, Insecticide and Mineral Fertilizer Mixtures Depending on Water Quality

    Directory of Open Access Journals (Sweden)

    Dušanka Inđić

    2008-01-01

    Full Text Available The paper deals with the effect of water quality on the pH value of fungicides, insecticides, mineral fertilizers and their mixtures. The fungicides propineb (Antracol WP-70 and mancozeb (Dithane M-70, insecticides pirimiphos-methyl (Actellic-50 and imidacloprid(Confidor 200-SL, several fertilizers (Ferticare I, Ferticare II, Ferticare III and Wuxal Super and their mixtures were analyzed for pH value under laboratory conditions using a potentiometric pH meter. Measurements were made directly after preparation or mixing with tap and well water and 24 hours later. Tap water exhibited a neutral reaction. A slightly alkaline reaction of well water was mostlikely due to high ammonium content. The suspensions of Antracol WP-70 exhibited slightly alkaline reactions with both water types during 24 hours. The spray liquids of Dithane M-70 mixed with tap or well water had neutral reaction after preparation and slightly alkaline reaction after 24 hours. The emulsions of Actellic-50 showed neutral reaction with both water types, followed by a pH increase in tap water after 24 hours. The solutions of Confidor200-SL had a slightly alkaline reaction after mixing and the pH value increased with both water types after 24 hours. It is therefore recommended to apply these insecticides directly after preparation. Mineral fertilizers considerably reduced pH values of the fungicide and insecticide components in double and triple mixtures, especially Ferticare nutrients which had a moderately acid reaction. Wuxal Super had a neutral reaction with both water types.The mixtures with well water increased pH values, which indicates that water pH does affect the pH value of the mixture. Both individual fertilizers and all mixtures (double and triple with Ferticare had pH values between 2.4 and 6, which allows their active liquids to be stored for 12 to 24 hours. The suspensions (Antracol WP-70, double and triple mixtures, emulsions (Actellic-50 and Actellic-50+Wuxal Super

  6. Morphological and Strength Properties of Tanjung Bin Coal Ash Mixtures for applied in Geotechnical Engineering Work

    Directory of Open Access Journals (Sweden)

    Abd. Rahim Awang

    2012-01-01

    Full Text Available In Malaysia, coal has been used as a raw material to generate electricity since 1988. In the past, most of the wastage of coal burning especially the bottom ash was not managed properly as it was dumped in the waste pond and accumulated drastically.This paper focuses on some properties of coal ash mixtures (fly  ash and bottom ash mixtures from Tanjung Bin power plant. The characteristics studied were morphological properties, compaction behaviour and strength properties. Strength properties of coal ash mixtures are carried out by conducting direct shear test and unconfined compression test. Besides, morphology and mineralogy of coal ash mixtures are studied using scanning electron microscope (SEM and x-ray diffraction (XRD. The coal ash mixtures were compacted at 95% of maximum dry density, sealed and cured for 0, 14, and 28 days before they were analysed for shear strength, morphological and mineralogical analyses. The shear strength of coal ash mixtures varied depending on the fly ash compositions. The maximum shear strength was obtained at mixture with 50%FA: 50%BA and the value increased with curing periods. The friction angle obtained ranged from 27° to 37°. Morphological analysis showed that the number of irregular shaped particles increased confirming change in material type with curing period. From mineralogical analysis, the crystalline compounds present in Tanjung Bin coal ash were Mullite, Quartz, Calcium Phosphide, Calcite, Cristobalite and Hematite. It can be concluded that the coal ash mixtures can advantageously be applied in the construction of embankments, roads, reclamation and fill behind retaining structures.

  7. Properties of Direct Coal Liquefaction Residue Modified Asphalt Mixture

    Directory of Open Access Journals (Sweden)

    Jie Ji

    2017-01-01

    Full Text Available The objectives of this paper are to use Direct Coal Liquefaction Residue (DLCR to modify the asphalt binders and mixtures and to evaluate the performance of modified asphalt mixtures. The dynamic modulus and phase angle of DCLR and DCLR-composite modified asphalt mixture were analyzed, and the viscoelastic properties of these modified asphalt mixtures were compared to the base asphalt binder SK-90 and Styrene-Butadiene-Styrene (SBS modified asphalt mixtures. The master curves of the asphalt mixtures were shown, and dynamic and viscoelastic behaviors of asphalt mixtures were described using the Christensen-Anderson-Marasteanu (CAM model. The test results show that the dynamic moduli of DCLR and DCLR-composite asphalt mixtures are higher than those of the SK-90 and SBS modified asphalt mixtures. Based on the viscoelastic parameters of CAM models of the asphalt mixtures, the high- and low-temperature performance of DLCR and DCLR-composite modified asphalt mixtures are obviously better than the SK-90 and SBS modified asphalt mixtures. In addition, the DCLR and DCLR-composite modified asphalt mixtures are more insensitive to the frequency compared to SK-90 and SBS modified asphalt mixtures.

  8. Thermodiffusion in binary and ternary nonpolar hydrocarbon + alcohol mixtures

    Science.gov (United States)

    Eslamian, Morteza; Saghir, M. Ziad

    2012-12-01

    Thermodiffusion in complex mixtures, such as associating, molten metal, and polymer mixtures is difficult to model usually owing to the occurrence of a sign change in the thermodiffusion coefficient when the mixture concentration and temperature change. A mixture comprised of a nonpolar hydrocarbon and an alcohol is a complex and highly non-ideal mixture. In this paper an existing binary non-equilibrium thermodynamics model (Eslamian and Saghir, Physical Review E 80, 061201, 2009) developed for aqueous mixtures of alcohols is examined against the experimental data of binary nonpolar hydrocarbon and alcohol mixtures. For ternary mixtures, non-equilibrium thermodynamic expressions developed by the authors for aqueous mixtures of alcohols (Eslamian and Saghir, Canadian Journal of Chemical Engineering, DOI 10.1002/cjce.20581) is used to predict thermodiffusion coefficients of ternary nonpolar hydrocarbon and alcohol mixtures. The rationale behind the sign change is elucidated and attributed to an anomalous change in the molecular structure and therefore viscosity of such mixtures. Model predictions of thermodiffusion coefficients of binary mixtures predict a sign change consistent with the experimental data although the model is still too primitive to capture all structural complexities. For instance, in the methanol-benzene mixture where the model predictions are poorest, the viscosity data show that when concentration varies, the mixture's molecular structure experiences a severe change twice, the first major change leading to a maximum in the thermodiffusion coefficient, whereas the second change causes a sign change.

  9. [Estimation of Hunan forest carbon density based on spectral mixture analysis of MODIS data].

    Science.gov (United States)

    Yan, En-ping; Lin, Hui; Wang, Guang-xing; Chen, Zhen-xiong

    2015-11-01

    With the fast development of remote sensing technology, combining forest inventory sample plot data and remotely sensed images has become a widely used method to map forest carbon density. However, the existence of mixed pixels often impedes the improvement of forest carbon density mapping, especially when low spatial resolution images such as MODIS are used. In this study, MODIS images and national forest inventory sample plot data were used to conduct the study of estimation for forest carbon density. Linear spectral mixture analysis with and without constraint, and nonlinear spectral mixture analysis were compared to derive the fractions of different land use and land cover (LULC) types. Then sequential Gaussian co-simulation algorithm with and without the fraction images from spectral mixture analyses were employed to estimate forest carbon density of Hunan Province. Results showed that 1) Linear spectral mixture analysis with constraint, leading to a mean RMSE of 0.002, more accurately estimated the fractions of LULC types than linear spectral and nonlinear spectral mixture analyses; 2) Integrating spectral mixture analysis model and sequential Gaussian co-simulation algorithm increased the estimation accuracy of forest carbon density to 81.5% from 74.1%, and decreased the RMSE to 5.18 from 7.26; and 3) The mean value of forest carbon density for the province was 30.06 t · hm(-2), ranging from 0.00 to 67.35 t · hm(-2). This implied that the spectral mixture analysis provided a great potential to increase the estimation accuracy of forest carbon density on regional and global level.

  10. Spectral mixture analysis of EELS spectrum-images

    Energy Technology Data Exchange (ETDEWEB)

    Dobigeon, Nicolas [University of Toulouse, IRIT/INP-ENSEEIHT, 2 rue Camichel, 31071 Toulouse Cedex 7 (France); Brun, Nathalie, E-mail: nathalie.brun@u-psud.fr [University of Paris Sud, Laboratoire de Physique des Solides, CNRS, UMR 8502, 91405 Orsay Cedex (France)

    2012-09-15

    Recent advances in detectors and computer science have enabled the acquisition and the processing of multidimensional datasets, in particular in the field of spectral imaging. Benefiting from these new developments, Earth scientists try to recover the reflectance spectra of macroscopic materials (e.g., water, grass, mineral types Horizontal-Ellipsis ) present in an observed scene and to estimate their respective proportions in each mixed pixel of the acquired image. This task is usually referred to as spectral mixture analysis or spectral unmixing (SU). SU aims at decomposing the measured pixel spectrum into a collection of constituent spectra, called endmembers, and a set of corresponding fractions (abundances) that indicate the proportion of each endmember present in the pixel. Similarly, when processing spectrum-images, microscopists usually try to map elemental, physical and chemical state information of a given material. This paper reports how a SU algorithm dedicated to remote sensing hyperspectral images can be successfully applied to analyze spectrum-image resulting from electron energy-loss spectroscopy (EELS). SU generally overcomes standard limitations inherent to other multivariate statistical analysis methods, such as principal component analysis (PCA) or independent component analysis (ICA), that have been previously used to analyze EELS maps. Indeed, ICA and PCA may perform poorly for linear spectral mixture analysis due to the strong dependence between the abundances of the different materials. One example is presented here to demonstrate the potential of this technique for EELS analysis. -- Highlights: Black-Right-Pointing-Pointer EELS spectrum images are identical to hyperspectral images for Earth science. Black-Right-Pointing-Pointer Spectral unmixing algorithms have proliferated in the remote sensing field. Black-Right-Pointing-Pointer These powerful techniques can be successfully applied to EELS mapping. Black-Right-Pointing-Pointer Potential

  11. The Soret Effect in Liquid Mixtures - A Review

    Science.gov (United States)

    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.

  12. Some Properties of Emulsified Asphalt Paving Mixture at Iraqi Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Shakir.A.Al-Mishhadani

    2014-02-01

    Full Text Available Cold emulsified asphalt mixture is generally a mix made of emulsified asphalt withaggregate. Emulsified asphalt is manufactured from base asphalt, emulsifier agent and waterwith approximate percentage of 40% to 75% asphalt, 0.1% to 2.5% emulsifier and 25% to60% water plus some minor components. This study aims to use the cold emulsified asphaltmixtures for road construction and maintenance in Iraq as an alternative to the hot asphaltmixtures, due to its economical, practical and environmental advantages. This studyfocusedto test and evaluates the emulsified asphalt material properties to be used as paving mixture.The tested properties of emulsified asphalt mixture were bulk density, air voids, dry Marshallstability, wet Marshall stability, retained Marshall stability, flow tests and compared with thecommon used specification.The results indicate that the emulsified asphalt type cationic slowsetting low viscosity (CSS-1 is very suitable with quartz type of aggregate from Al-Nibaayquarry. From many trial mixes it is found that the best percentages of initial residual bitumencontent to produced adequateresults for coating test ,mixing ,compaction ,curing and Marshallstability were ranged from (2.5%, 3%,3.5%,4% and 4.5%, andthe optimum percentage is(3.5%.Finally it can be conducted that the emulsified asphalt mixture is a suitable alternativemixture to the hot asphalt mixture for road construction and maintenance in Iraq.

  13. Some Properties of Emulsified Asphalt Paving Mixture at Iraqi Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Shakir.A.Al-Mishhadani* Hasan.H.Al-Baid

    2014-04-01

    Full Text Available Cold emulsified asphalt mixture is generally a mix made of emulsified asphalt withaggregate. Emulsified asphalt is manufactured from base asphalt, emulsifier agent and waterwith approximate percentage of 40% to 75% asphalt, 0.1% to 2.5% emulsifier and 25% to60% water plus some minor components. This study aims to use the cold emulsified asphaltmixtures for road construction and maintenance in Iraq as an alternative to the hot asphaltmixtures, due to its economical, practical and environmental advantages. This studyfocusedto test and evaluates the emulsified asphalt material properties to be used as paving mixture.The tested properties of emulsified asphalt mixture were bulk density, air voids, dry Marshallstability, wet Marshall stability, retained Marshall stability, flow tests and compared with thecommon used specification.The results indicate that the emulsified asphalt type cationic slowsetting low viscosity (CSS-1 is very suitable with quartz type of aggregate from Al-Nibaayquarry. From many trial mixes it is found that the best percentages of initial residual bitumencontent to produced adequateresults for coating test ,mixing ,compaction ,curing and Marshallstability were ranged from (2.5%, 3%,3.5%,4% and 4.5%, andthe optimum percentage is(3.5%.Finally it can be conducted that the emulsified asphalt mixture is a suitable alternativemixture to the hot asphalt mixture for road construction and maintenance in Iraq.  

  14. Experimental study of two-dimensional helium mixture films adsorbed on graphite

    CERN Document Server

    Patel, H

    2002-01-01

    sup 3 He- sup 4 He mixture films adsorbed on graphite were studied down to temperatures below 1 mK using heat capacity and nuclear magnetic resonance (NMR) to probe the system. This work represents the first measurements in this temperature range of the various systems studied. The work focused on two types of mixtures, sup 3 He- sup 4 He mixtures within the second layer, and sup 3 He floating on three layers of sup 4 He. For mixtures within the layer, a homogeneous mixed phase was observed, followed by a phase interpreted as a Fermi liquid of sup 3 He quasiparticle excitations tunneling within a solid sup 4 He lattice. For the second type of mixture, the expected occupancy of the first excited surface normal state was observed. This is accompanied by anomalous behaviour at low temperatures (T < 10 mK) which arises due to a low concentration of sup 3 He atoms being pushed into the third superfluid sup 4 He layer. An NMR spectrometer utilising a cooled differential preamplifier operating at 4 K was develope...

  15. Faraday waves in quasi-one-dimensional superfluid Fermi-Bose mixtures

    DEFF Research Database (Denmark)

    Abdullaev, F. Kh.; Ögren, Magnus; Sørensen, Mads Peter

    2013-01-01

    The generation of Faraday waves in superfluid Fermi-Bose mixtures in elongated traps is investigated. The generation of waves is achieved by periodically changing a parameter of the system in time. Two types of modulations of parameters are considered: a variation of the fermion-boson scattering...

  16. Complex mixtures, complex responses: Assessing pharmaceutical mixtures using field and laboratory approaches

    Science.gov (United States)

    Schoenfuss, Heiko L.; Furlong, Edward T.; Phillips, Patrick J.; Scott, Tia-Marie; Kolpin, Dana W.; Cetkovic-Cvrlje, Marina; Lesteberg, Kelsey E.; Rearick, Daniel C.

    2016-01-01

    Pharmaceuticals are present in low concentrations (tramadol), a muscle relaxant (methocarbamol), a simple antidepressant mixture (fluoxetine, paroxetine, venlafaxine), a sleep aid (temazepam), or a complex mixture of all compounds. Larval minnow response to effluent exposure was not consistent. The 2010 exposures resulted in shorter exposed minnow larvae, whereas the larvae exposed in 2012 exhibited altered escape behavior. Mature minnows exhibited altered hepatosomatic indices, with the strongest effects in females and in mixture exposures. In addition, laboratory-exposed, mature male minnows exposed to all pharmaceuticals (except the selective serotonin reuptake inhibitor mixture) defended nest sites less rigorously than fish in the control group. Tramadol or antidepressant mixture exposure resulted in increased splenic T lymphocytes. Only male minnows exposed to whole effluent responded with increased plasma vitellogenin concentrations. Female minnows exposed to pharmaceuticals (except the opioid mixture) had larger livers, likely as a compensatory result of greater prominence of vacuoles in liver hepatocytes. The observed alteration of apical endpoints central to sustaining fish populations confirms that effluents containing waste streams from pharmaceutical formulation facilities can adversely impact fish populations but that the effects may not be temporally consistent. The present study highlights the importance of including diverse biological endpoints spanning levels of biological organization and life stages when assessing contaminant interactions.

  17. Evaluation of yielding of mixtures of Pisum sativum L. with Triticum aestivum L. grown in organic farming

    Directory of Open Access Journals (Sweden)

    Jerzy Księżak

    2016-09-01

    Full Text Available The aim of this study was to determine the productivity and quality of feed obtained from the mixtures of field pea (Pisum sativum L. with spring wheat (Triticum aestivum L., depending on the pea cultivar and its percentage in the weight of sown seeds under the conditions of organic farming. A field experiment was carried out in the years 2011–2013 in a randomized split-plot design with four replications. The first factor was a pea ‘Wiato’ or ‘Tarchalska’. The secondary factor was density of a pea mixture sown: 40, 60, and 80%. The yield of mixture seeds as well as the yield and structure of individual components were evaluated. The contents of crude protein and crude fiber, fat, ash, phosphorus, and potassium were determined in cereal grain and pea seeds. The examined factors and weather conditions during the growing season had a significant impact on the growth and yield of pea–spring wheat mixtures. The seed yields of the mixtures with the semi-leafless ‘Tarchalska’ were lower than with ‘Wiato’ (with bipinnate leaves. Increasing the pea percentage in seed material resulted in lower mixture yields. The percentage of pea seeds (regardless of foliage type in the mixture yields was significantly lower than the weight of sown seeds. Increasing the pea percentage in the mixture yield positively influenced the contents of protein, fat, and ash but it caused a decrease in the content of fiber. The pea percentage at sowing had little influence on the content of phosphorus in the mixture seed yields, but it slightly increased the content of potassium, regardless of the pea cultivar. The mixtures with the ‘Wiato’ and ‘Tarchalska’ cultivars contained a similar amount of protein, fiber, and fat, while the mixtures with ‘Tarchalska’ accumulated more ash.

  18. A mixture detection method based on separate amplification using primer specific alleles of INDELs-a study based on two person's DNA mixture.

    Science.gov (United States)

    Liu, Jinding; Wang, Jiaqi; Zhang, Xiaojia; Li, Zeqin; Yun, Keming; Liu, Zhizhen; Zhang, Gengqian

    2017-02-01

    Samples containing unbalanced DNA mixtures from individuals often occur in forensic DNA examination and clinical detection. Because of the PCR amplification bias, the minor contributor DNA is often masked by the major contributor DNA when using traditional STR or SNP typing techniques. Here we propose a method based in allele-specific Insertion/Deletion (INDEL) genotyping to detect DNA mixtures in forensic samples. Fourteen INDELs were surveyed in the Chinese Han population of Shanxi Province. The INDELs were amplified using two separate primer-specific reactions by real-time PCR. The difference Ct value of the 2 reactions (D-value) were used for determination of the single source DNA. INDELs types and further confirmed by electrophoresis separation. The minor allele frequency (MAF) was above 0.2 in 10 INDELs. The detection limit was 0.3125 ng-1.25 ng template DNA for real-time PCR in all 14 INDEL markers. For single source 10 ng DNA, the average D-value was 0.31 ± 0.14 for LS type, 6.96 ± 1.05 for LL type and 7.20 ± 1.09 for SS type. For the series of simulated DNA mixture, the Ct value varied between the ranges of single source DNA, depending on their INDEL typing and mixture ratios. This method can detect the specific allele of the minor DNA contributor as little as 1:50 in rs397782455 and rs397696936; 1:100 in rs397832665, rs397822382 and rs397897230; the detection limit of the minor DNA contributor was as little as 1:500-1:1000 in the rest INDEL markers, a much higher sensitivity compared with traditional STR typing. The D-value variation depended on the alternation of dilution ratio and INDEL types. When the dilution was 1:1000, the maximum and minimum D-values were 8.84 ± 0.11 in rs397897230 and 4.27 ± 0.19 in rs397897239 for LL and SS type mixture, the maximum and minimum D-values were 9.32 ± 0.54 in rs397897230 and 4.38 ± 0.26 in rs 397897239 for LL(SS) and LS type mixture, separately. Any D-value between 0.86 and 5.11 in the 14

  19. Molecular thermodiffusion (thermophoresis) in liquid mixtures.

    Science.gov (United States)

    Semenov, Semen N; Schimpf, Martin E

    2005-10-01

    Thermodiffusion (thermophoresis) in liquid mixtures is theoretically examined using a hydrodynamic approach. Thermodiffusion is related to the local temperature-induced pressure gradient in the liquid layer surrounding the selected molecule and to the secondary macroscopic pressure gradient established in the system. The local pressure gradient is produced by excess pressure due to the asymmetry of interactions with surrounding molecules in a nonuniform temperature field. The secondary pressure gradient is considered an independent parameter related to the concentration gradient formed by volume forces, calculated from the generalized equations for mass transfer. Values of Soret coefficients for mixtures of toluene and -hexane are calculated using parameters in the literature. When the molecules are assumed to be similar in shape, the calculated Soret coefficients are lower than the empirical values found in the literature. However, by introducing an asymmetry parameter, which is calculated from independent measurements of component diffusion in the literature, very good agreement is obtained.

  20. Quantum state smoothing for classical mixtures

    CERN Document Server

    Tan, D; Mølmer, K; Murch, K W

    2016-01-01

    In quantum mechanics, wave functions and density matrices represent our knowledge about a quantum system and give probabilities for the outcomes of measurements. If the combined dynamics and measurements on a system lead to a density matrix $\\rho(t)$ with only diagonal elements in a given basis $\\{|n\\rangle\\}$, it may be treated as a classical mixture, i.e., a system which randomly occupies the basis states $|n\\rangle$ with probabilities $\\rho_{nn}(t)$. Fully equivalent to so-called smoothing in classical probability theory, subsequent probing of the occupation of the states $|n\\rangle$ improves our ability to retrodict what was the outcome of a projective state measurement at time $t$. Here, we show with experiments on a superconducting qubit that the smoothed probabilities do not, in the same way as the diagonal elements of $\\rho$, permit a classical mixture interpretation of the state of the system at the past time $t$.

  1. Excess compressibility in binary liquid mixtures.

    Science.gov (United States)

    Aliotta, F; Gapiński, J; Pochylski, M; Ponterio, R C; Saija, F; Salvato, G

    2007-06-14

    Brillouin scattering experiments have been carried out on some mixtures of molecular liquids. From the measurement of the hypersonic velocities we have evaluated the adiabatic compressibility as a function of the volume fraction. We show how the quadratic form of the excess compressibility dependence on the solute volume fraction can be derived by simple statistical effects and does not imply any interaction among the components of the system other than excluded volume effects. This idea is supported by the comparison of the experimental results with a well-established prototype model, consisting of a binary mixture of hard spheres with a nonadditive interaction potential. This naive model turns out to be able to produce a very wide spectrum of structural and thermodynamic features depending on values of its parameters. An attempt has made to understand what kind of structural information can be gained through the analysis of the volume fraction dependence of the compressibility.

  2. The Supervised Learning Gaussian Mixture Model

    Institute of Scientific and Technical Information of China (English)

    马继涌; 高文

    1998-01-01

    The traditional Gaussian Mixture Model(GMM)for pattern recognition is an unsupervised learning method.The parameters in the model are derived only by the training samples in one class without taking into account the effect of sample distributions of other classes,hence,its recognition accuracy is not ideal sometimes.This paper introduces an approach for estimating the parameters in GMM in a supervising way.The Supervised Learning Gaussian Mixture Model(SLGMM)improves the recognition accuracy of the GMM.An experimental example has shown its effectiveness.The experimental results have shown that the recognition accuracy derived by the approach is higher than those obtained by the Vector Quantization(VQ)approach,the Radial Basis Function (RBF) network model,the Learning Vector Quantization (LVQ) approach and the GMM.In addition,the training time of the approach is less than that of Multilayer Perceptrom(MLP).

  3. Sum of Bernoulli Mixtures: Beyond Conditional Independence

    Directory of Open Access Journals (Sweden)

    Taehan Bae

    2014-01-01

    Full Text Available We consider the distribution of the sum of Bernoulli mixtures under a general dependence structure. The level of dependence is measured in terms of a limiting conditional correlation between two of the Bernoulli random variables. The conditioning event is that the mixing random variable is larger than a threshold and the limit is with respect to the threshold tending to one. The large-sample distribution of the empirical frequency and its use in approximating the risk measures, value at risk and conditional tail expectation, are presented for a new class of models which we call double mixtures. Several illustrative examples with a Beta mixing distribution, are given. As well, some data from the area of credit risk are fit with the models, and comparisons are made between the new models and also the classical Beta-binomial model.

  4. Robust classification using mixtures of dependency networks

    DEFF Research Database (Denmark)

    Gámez, José A.; Mateo, Juan L.; Nielsen, Thomas Dyhre

    2008-01-01

    Dependency networks have previously been proposed as alternatives to e.g. Bayesian networks by supporting fast algorithms for automatic learning. Recently dependency networks have also been proposed as classification models, but as with e.g. general probabilistic inference, the reported speed......-ups are often obtained at the expense of accuracy. In this paper we try to address this issue through the use of mixtures of dependency networks. To reduce learning time and improve robustness when dealing with data sparse classes, we outline methods for reusing calculations across mixture components. Finally......, the proposed model is empirically compared to other state-of-the-art classifiers, both in terms of accuracy and learning time....

  5. Lattice Model for water-solute mixtures

    OpenAIRE

    Furlan, A. P.; Almarza, N. G.; M. C. Barbosa

    2016-01-01

    A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting on, hydrophilic, inert and hydrophobic interactions. Extensive Monte Carlo simulations were carried out and the behavior of pure components and the excess proper...

  6. Fluorous Mixture Synthesis of Asymmetric Dendrimers

    Science.gov (United States)

    Jiang, Zhong-Xing; Yu, Yihua Bruce

    2010-01-01

    A divergent fluorous mixture synthesis (FMS) of asymmetric fluorinated dendrimers has been developed. Four generations of fluorinated dendrimers with the same fluorinated moiety were prepared with high efficiency, yield and purity. Comparison of the physicochemical properties of these dendrimers provided valuable information for their application and future optimization. This strategy has not only provided a practical method for the synthesis and purification of dendrimers, but also established the possibility of utilizing the same fluorinated moiety for FMS. PMID:20170088

  7. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  8. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  9. Endocrine activity of mycotoxins and mycotoxin mixtures.

    Science.gov (United States)

    Demaegdt, Heidi; Daminet, Britt; Evrard, Annick; Scippo, Marie-Louise; Muller, Marc; Pussemier, Luc; Callebaut, Alfons; Vandermeiren, Karine

    2016-10-01

    Reporter gene assays incorporating nuclear receptors (estrogen, androgen, thyroid β and PPARγ2) have been implemented to assess the endocrine activity of 13 mycotoxins and their mixtures. As expected, zearalenone and its metabolites α-zearalenol and β- zearalenol turned out to have the strongest estrogenic potency (EC50 8,7 10-10 ± 0,8; 3,1 10-11 ± 0,5 and 1,3 10-8 ± 0,3 M respectively). The metabolite of deoxynivalenol, 3-acetyl-deoxynivalenol also had estrogenic activity (EC50 3,8 10-7 ± 1,1 M). Furthermore, most of the mycotoxins (and their mixtures) showed anti-androgenic effects (15-acetyldeoxynivalenol, 3-acetyl-deoxynivalenol and α-zearalenol with potencies within one order of magnitude of that of the reference compound flutamide). In particular, deoxynivalenol and 15-acetyl-deoxynivalenol acted as antagonists for the PPARy2 receptor. When testing mixtures of mycotoxins on the same cell systems, we showed that most of the mixtures reacted as predicted by the concentration addition (CA) theory. Generally, the CA was within the 95% confidence interval of the observed ones, only minor deviations were detected. Although these reporter gene tests cannot be directly extrapolated in vivo, they can be the basis for further research. Especially the additive effects of ZEN and its metabolites are of importance and could have repercussions in vivo.

  10. Method for Predicting Hypergolic Mixture Flammability Limits

    Science.gov (United States)

    2017-02-01

    AFRL-AFOSR-UK-TR-2017-0003 Method for Predicting Hypergolic Mixture Flammability Limits Laurent Catoire Ecole Nat Sup De Techniques Avancees Final...TASK NUMBER 5f.  WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Ecole Nat Sup De Techniques Avancees 828, Boulevard Des Marechaux...provides a mitigation strategy to reduce the risk of failure for the insertion of IL fuel technology into the small satellite market as AFRL/RQRP

  11. Population mixture model for nonlinear telomere dynamics

    Science.gov (United States)

    Itzkovitz, Shalev; Shlush, Liran I.; Gluck, Dan; Skorecki, Karl

    2008-12-01

    Telomeres are DNA repeats protecting chromosomal ends which shorten with each cell division, eventually leading to cessation of cell growth. We present a population mixture model that predicts an exponential decrease in telomere length with time. We analytically solve the dynamics of the telomere length distribution. The model provides an excellent fit to available telomere data and accounts for the previously unexplained observation of telomere elongation following stress and bone marrow transplantation, thereby providing insight into the nature of the telomere clock.

  12. Hierarchical mixture models for assessing fingerprint individuality

    OpenAIRE

    Dass, Sarat C.; Li, Mingfei

    2009-01-01

    The study of fingerprint individuality aims to determine to what extent a fingerprint uniquely identifies an individual. Recent court cases have highlighted the need for measures of fingerprint individuality when a person is identified based on fingerprint evidence. The main challenge in studies of fingerprint individuality is to adequately capture the variability of fingerprint features in a population. In this paper hierarchical mixture models are introduced to infer the extent of individua...

  13. Geotechnical Properties of Rubber Tires and Sediments Mixtures

    Directory of Open Access Journals (Sweden)

    H. Sellaf

    2014-04-01

    Full Text Available An experimental work was undertaken to study the effect of rubber tires on the geotechnical properties of a dredged sediment, using a mixing ratio of large size. For comparison, two types of soil were studied (dredged sediment from Fergoug dam and Tizi Tuff from the north west of Algeria. Taking into account the high compressibility and the low water absorption of the rubber tires, grain size analysis, density, Atterberg limits analysis, chemical composition, direct shear tests, loading-unloading tests, modified Proctor and CBR tests are performed on the two soils and their mixtures with different scrap tire rubber (10, 20, 25 and 50%. The results show that liquid limits and plastic indexes decrease with the scrap tire rubber content and that the decrease is more significant for soil with high plasticity. Cohesion also decreases with scrap tire rubber content when the internal friction angle is vacillating. Compression and recompression indexes increase gradually with the scrap tire rubber content and the variation for compression index is more significant for the two soils. Compaction characteristics and CBR values decrease with scrap tire rubber content. The CBR values for W=3% are important compared to those with W=5% excepted for mixture with (75% tuff and 25% scrap tire rubber. The results show that the scrap tire rubber can be used as a reinforcement material for dredged soil, but with a content that should not highly affect the compressibility.

  14. Liquid-liquid equilibria for ternary polymer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Suk Yung [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: ycbae@hanyang.ac.kr [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-01-24

    Graphical abstract: We developed a molecular thermodynamic model for multicomponent systems and discribed the phase equilibrium for ternary polymer mixtures by using the model parameters obtained from the binary systems. Research highlights: {yields} Model parameters were obtained from the binary systems. {yields} The obtained parameters were directly used to predict the ternary data. {yields} The undetermined parameters were used to correlate the ternary data. {yields} The proposed model agreed well with the experimental data. - Abstract: A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  15. A Variational approach to thin film hydrodynamics of binary mixtures

    KAUST Repository

    Xu, Xinpeng

    2015-02-04

    In order to model the dynamics of thin films of mixtures, solutions, and suspensions, a thermodynamically consistent formulation is needed such that various coexisting dissipative processes with cross couplings can be correctly described in the presence of capillarity, wettability, and mixing effects. In the present work, we apply Onsager\\'s variational principle to the formulation of thin film hydrodynamics for binary fluid mixtures. We first derive the dynamic equations in two spatial dimensions, one along the substrate and the other normal to the substrate. Then, using long-wave asymptotics, we derive the thin film equations in one spatial dimension along the substrate. This enables us to establish the connection between the present variational approach and the gradient dynamics formulation for thin films. It is shown that for the mobility matrix in the gradient dynamics description, Onsager\\'s reciprocal symmetry is automatically preserved by the variational derivation. Furthermore, using local hydrodynamic variables, our variational approach is capable of introducing diffusive dissipation beyond the limit of dilute solute. Supplemented with a Flory-Huggins-type mixing free energy, our variational approach leads to a thin film model that treats solvent and solute in a symmetric manner. Our approach can be further generalized to include more complicated free energy and additional dissipative processes.

  16. Statistical mechanical theory of fluid mixtures

    Science.gov (United States)

    Zhao, Yueqiang; Wu, Zhengming; Liu, Weiwei

    2014-01-01

    A general statistical mechanical theory of fluid mixtures (liquid mixtures and gas mixtures) is developed based on the statistical mechanical expression of chemical potential of components in the grand canonical ensemble, which gives some new relationships between thermodynamic quantities (equilibrium ratio Ki, separation factor α and activity coefficient γi) and ensemble average potential energy u for one molecule. The statistical mechanical expressions of separation factor α and activity coefficient γi derived in this work make the fluid phase equilibrium calculations can be performed by molecular simulation simply and efficiently, or by the statistical thermodynamic approach (based on the saturated-vapor pressure of pure substance) that does not need microscopic intermolecular pair potential functions. The physical meaning of activity coefficient γi in the liquid phase is discussed in detail from a viewpoint of molecular thermodynamics. The calculated Vapor-Liquid Equilibrium (VLE) properties of argon-methane, methanol-water and n-hexane-benzene systems by this model fit well with experimental data in references, which indicates that this model is accurate and reliable in the prediction of VLE properties for small, large and strongly associating molecules; furthermore the statistical mechanical expressions of separation factor α and activity coefficient γi have good compatibility with classical thermodynamic equations and quantum mechanical COSMO-SAC approach.

  17. Ethane-xenon mixtures under shock conditions

    Science.gov (United States)

    Flicker, Dawn; Magyar, Rudolph; Root, Seth; Cochrane, Kyle; Mattsson, Thomas

    2015-06-01

    Mixtures of light and heavy elements arise in inertial confinement fusion and planetary science. We present results on the physics of molecular scale mixing through a validation study of equation of state (EOS) properties. Density functional theory molecular dynamics (DFT/QMD) at elevated-temperature and pressure is used to obtain the properties of pure xenon, ethane, and various compressed mixture compositions along their principal Hugoniots. To validate the QMD simulations, we performed high-precision shock compression experiments using Sandia's Z-Machine. A bond tracking analysis of the simulations correlates the sharp rise in the Hugoniot curve with completion of dissociation in ethane. DFT-based simulation results compare well with experimental data and are used to provide insight into the dissociation as a function of mixture composition. Interestingly, we find that the compression ratio for complete dissociation is similar for ethane, Xe-ethane, polymethyl-pentene, and polystyrene, suggesting that a limiting compression exists for C-C bonded systems. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, Security Administration under contract DE-AC04-94AL85000.

  18. Crowding in polymer-nanoparticle mixtures.

    Science.gov (United States)

    Denton, Alan R

    2014-01-01

    The cell nucleus is a highly crowded environment, filled with a multicomponent, polydisperse mixture of biopolymers and nuclear bodies dispersed in a viscous solvent. With volume fractions approaching 20%, excluded-volume interactions play a key role in determining the structure, dynamics, and function of macromolecules in vivo. Under such constraints, the ensembles of macromolecular conformations can differ substantially from those prevailing in dilute solutions. Crowding thus can affect protein and RNA folding, conformational stability, and reaction kinetics, as well as phase stability of macromolecular mixtures. From the perspective of soft matter physics, this chapter reviews recent studies on crowding in polymer-nanoparticle mixtures, seeking to demonstrate the utility of simple physical models for addressing challenging issues in cell biology. The focus is on applications of free-volume theory and Monte Carlo simulation, based on geometrical models of polymers as fluctuating spheres or ellipsoids. Ideal polymer coils respond to hard-sphere crowding agents by compactifying, reducing their radius of gyration, and becoming more spherical. At sufficiently high concentrations, polymers and crowders phase-separate. The goal of this review is to identify universal principles governing macromolecular crowding and to establish a general framework for future explorations of more realistic models that may include nonsteric (e.g., electrostatic) interactions. © 2014 Elsevier Inc. All rights reserved.

  19. Mixture risk assessment: a case study of Monsanto experiences.

    Science.gov (United States)

    Nair, R S; Dudek, B R; Grothe, D R; Johannsen, F R; Lamb, I C; Martens, M A; Sherman, J H; Stevens, M W

    1996-01-01

    Monsanto employs several pragmatic approaches for evaluating the toxicity of mixtures. These approaches are similar to those recommended by many national and international agencies. When conducting hazard and risk assessments, priority is always given to using data collected directly on the mixture of concern. To provide an example of the first tier of evaluation, actual data on acute respiratory irritation studies on mixtures were evaluated to determine whether the principle of additivity was applicable to the mixture evaluated. If actual data on the mixture are unavailable, extrapolation across similar mixtures is considered. Because many formulations are quite similar in composition, the toxicity data from one mixture can be extended to a closely related mixture in a scientifically justifiable manner. An example of a family of products where such extrapolations have been made is presented to exemplify this second approach. Lastly, if data on similar mixtures are unavailable, data on component fractions are used to predict the toxicity of the mixture. In this third approach, process knowledge and scientific judgement are used to determine how the known toxicological properties of the individual fractions affect toxicity of the mixture. Three examples of plant effluents where toxicological data on fractions were used to predict the toxicity of the mixture are discussed. The results of the analysis are used to discuss the predictive value of each of the above mentioned toxicological approaches for evaluating chemical mixtures.

  20. Physical and chemical clay binder characteristics from various locality and their influence on some technological properties of bentonite mouling mixtures

    Directory of Open Access Journals (Sweden)

    I. Vasková

    2010-01-01

    Full Text Available The aim of this paper is to explore the complex physical – chemical characteristics of bentonite of slovak provenance and to compare with non-slovak, which is considered as European highest quality standard in foundry and to compare from the point of foundry application. These characteristics of raw material have direct relationship with technological properties of bentonite sand mixtures and mainly with the quality of castings poured into these mixtures. To compare technological properties of bentonite forming mixtures with use of various clay types point of view application in foundry industry.

  1. Physical Compatibility of Propofol-Sufentanil Mixtures.

    Science.gov (United States)

    Zbytovská, Jarmila; Gallusová, Jana; Vidlářová, Lucie; Procházková, Kamila; Šimek, Jan; Štěpánek, František

    2017-03-01

    Combined infusions of propofol and sufentanil preparations are frequently used in clinical practice to induce anesthesia and analgesia. However, the stability of propofol emulsions can be affected by dilution with another preparation, sometimes leading to particle coalescence and enlargement. Such unwanted effects can lead to fat embolism syndrome after intravenous application. This study describes the physical stability of 5 commercially available propofol preparations mixed with sufentanil citrate solutions. Two common markers of emulsion stability were used in this study; namely, the zeta potential and size distribution of the emulsion droplets. Both were measured using dynamic light scattering. The data for the pure propofol preparations and their mixtures with sufentanil citrate solution were compared. The absolute value of zeta potential decreased in 4 of the 5 propofol preparations after they had been mixed with sufentanil citrate. This effect indicates a lowering of repulsive interactions between the emulsion droplets. Although this phenomenon tends to cause agglomeration, none of the studied mixtures displayed a substantial increase in droplet size within 24 hours of blending. However, our long-term stability study revealed the instability of some of the propofol-sufentanil samples. Two of the 5 studied mixtures displayed a continual increase in particle size. The same 2 preparations showed the greatest reductions in the absolute value of zeta potential, thereby confirming the correlation of both measurement methods. The increase in particle size was more distinct in the samples stored at higher temperatures and with higher sufentanil concentrations. To ensure the microbial stability of an emulsion infusion preparation, clinical regulations require that such preparations should be applied to patients within 12 hours of opening. In this respect, we can confirm that during this period, none of the studied propofol-sufentanil mixtures displayed any physical

  2. Separation of gas mixtures by supported complexes

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D.A.; Lilga, M.A.; Hallen, R.T.; Lyke, S.E.

    1986-08-01

    The goal of this program is to determine the feasibility of solvent-dissolved coordination complexes for the separation of gas mixtures under bench-scale conditions. In particular, mixtures such as low-Btu gas are examined for CO and H/sub 2/ separation. Two complexes, Pd/sub 2/(dpm)/sub 2/Br/sub 2/ and Ru(CO)/sub 2/(PPh/sub 3/)/sub 3/, were examined in a bench-scale apparatus for the separation of binary (CO-N/sub 2/ or H/sub 2/-N/sub 2/) and quinary (H/sub 2/, CO, CO/sub 2/, CH/sub 4/, and N/sub 2/) mixtures. The separation of CO-N/sub 2/ was enhanced by the presence of the palladium complex in the 1,1,2-trichloroethane (TCE) solvent, especially at high gas and low liquid rates. The five-component gas mixture separation with the palladium complex in TCE provided quite unexpected results based on physical solubility and chemical coordination. The complex retained CO, while the solvent retained CO/sub 2/, CH/sub 4/, and N/sub 2/ to varying degrees. This allowed the hydrogen content to be enhanced due to its low solubility in TCE and inertness to the complex. Thus, a one-step, hydrogen separation can be achieved from gas mixtures with compositions similar to that of oxygen-blown coal gas. A preliminary economic evaluation of hydrogen separation was made for a system based on the palladium complex. The palladium system has a separation cost of 50 to 60 cents/MSCF with an assumed capital investment of $1.60/MSCF of annual capacity charged at 30% per year. This assumes a 3 to 4 year life for the complex. Starting with a 90% hydrogen feed, PSA separation costs are in the range of 30 to 50 cents/MSCF. The ruthenium complex was not as successful for hydrogen or carbon monoxide separation due to unfavorable kinetics. The palladium complex was found to strip hydrogen gas from H/sub 2/S. The complex could be regenerated with mild oxidants which removed the sulfur as SO/sub 2/. 24 refs., 26 figs., 10 tabs.

  3. Mixtures as a fungicide resistance management tactic.

    Science.gov (United States)

    van den Bosch, Frank; Paveley, Neil; van den Berg, Femke; Hobbelen, Peter; Oliver, Richard

    2014-12-01

    We have reviewed the experimental and modeling evidence on the use of mixtures of fungicides of differing modes of action as a resistance management tactic. The evidence supports the following conclusions. 1. Adding a mixing partner to a fungicide that is at-risk of resistance (without lowering the dose of the at-risk fungicide) reduces the rate of selection for fungicide resistance. This holds for the use of mixing partner fungicides that have either multi-site or single-site modes of action. The resulting predicted increase in the effective life of the at-risk fungicide can be large enough to be of practical relevance. The more effective the mixing partner (due to inherent activity and/or dose), the larger the reduction in selection and the larger the increase in effective life of the at-risk fungicide. 2. Adding a mixing partner while lowering the dose of the at-risk fungicide reduces the selection for fungicide resistance, without compromising effective disease control. The very few studies existing suggest that the reduction in selection is more sensitive to lowering the dose of the at-risk fungicide than to increasing the dose of the mixing partner. 3. Although there are very few studies, the existing evidence suggests that mixing two at-risk fungicides is also a useful resistance management tactic. The aspects that have received too little attention to draw generic conclusions about the effectiveness of fungicide mixtures as resistance management strategies are as follows: (i) the relative effect of the dose of the two mixing partners on selection for fungicide resistance, (ii) the effect of mixing on the effective life of a fungicide (the time from introduction of the fungicide mode of action to the time point where the fungicide can no longer maintain effective disease control), (iii) polygenically determined resistance, (iv) mixtures of two at-risk fungicides, (v) the emergence phase of resistance evolution and the effects of mixtures during this phase

  4. The structural and thermodynamical properties of binary ellipsoidal fluid mixture Gay-Berne interaction

    Directory of Open Access Journals (Sweden)

    M. Moradi

    2007-06-01

    Full Text Available  In this paper, a uniform classical fluid mixture comprising ellipsoidal molecules is studied. This mixture is composed of two types of ellipsoidal molecules interacting through the Gay-Berne potential with different sizes at temperature T. For this system, the Ornstein-Zernike equation using the Percus-Yevick closure relation is solved. Then the direct correlation function, pair correlation function and the pressure of the fluid at temperature T are calculated. The obtained results are in agreement with the previous theories and the results of molecular dynamic computer simulation.

  5. Impact of dry heating on physicochemical properties of corn starch and lysine mixture.

    Science.gov (United States)

    Ji, Ying; Yu, Jicheng; Xu, Yongbin; Zhang, Yinghui

    2016-10-01

    Corn starch was modified with lysine by dry heat treatment and to investigate how they can affect the pasting and structural properties of the treated starches. Dry heating with lysine reduced the pasting temperature and resulting in viscosity increase. The particle size of heated starch-lysine mixture increased, suggesting that starch granules were cross-linked to lysine. After dry heating, the onset temperature, peak temperature and conclusion temperature of corn starch-lysine mixture were lower than those of other starches. The degree of crystallinity decreased for the starch after dry heat treatment while these heated starch samples still have the same X-ray diffraction types as the original starch.

  6. Capillary condensation of a binary mixture in slit-like pores.

    Science.gov (United States)

    Bucior, Katarzyna; Patrykiejew, Andrzej; Pizio, Orest; Sokołowski, Stefan

    2003-03-15

    We investigate the capillary condensation of two model fluid mixtures in slit-like pores, which exhibit different demixing properties in the bulk phase. The interactions between adsorbate particles are modeled by using Lennard-Jones (12,6) potentials and the adsorbing potentials are of the Lennard-Jones (9,3) type. The calculations are performed for different pore widths and at different concentrations of the bulk gas, by means of density functional theory. We evaluate the capillary phase diagrams and discuss their dependence on the parameters of the model. Our calculations indicate that a binary mixture confined to a slit-like pore may exhibit rich phase behavior.

  7. Investigation of rheological properties of mixtures of soft ice cream

    Directory of Open Access Journals (Sweden)

    L. V. Golubeva

    2012-01-01

    Full Text Available The paper presents the study of the rheological properties of multicomponent mixtures for soft ice cream enriched with various stabilizers to facilitate evaluation and selection of the optimal mixture.

  8. Methods for Assessing Curvature and Interaction in Mixture Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.(BATTELLE (PACIFIC NW LAB)); Hicks, Ruel D.(ASSOC WESTERN UNIVERSITY); Szychowski, Jeffrey M.(ASSOC WESTERN UNIVERSITY); Loeppky, Jason L.(ASSOC WESTERN UNIVERSITY)

    2002-05-01

    The terms curvature and interaction traditionally are not defined or used in the context of mixture experiments because curvature and interaction effects are partially confounded due to the mixture constrain that the component proportions sum to 1.

  9. Mixture Density Mercer Kernels: A Method to Learn Kernels

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a method of generating Mercer Kernels from an ensemble of probabilistic mixture models, where each mixture model is generated from a Bayesian...

  10. Optimal (Solvent) Mixture Design through a Decomposition Based CAMD methodology

    DEFF Research Database (Denmark)

    Achenie, L.; Karunanithi, Arunprakash T.; Gani, Rafiqul

    2004-01-01

    Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach is...... is able to overcome most of the difficulties associated with the solution of mixture design problems. The new methodology has been illustrated with the help of a case study involving the design of solvent-anti solvent binary mixtures for crystallization of Ibuprofen.......Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach...

  11. Analysis of Water Hammer with Different Closing Valve Laws on Transient Flow of Hydrogen-Natural Gas Mixture

    OpenAIRE

    Norazlina Subani; Norsarahaida Amin

    2015-01-01

    Water hammer on transient flow of hydrogen-natural gas mixture in a horizontal pipeline is analysed to determine the relationship between pressure waves and different modes of closing and opening of valves. Four types of laws applicable to closing valve, namely, instantaneous, linear, concave, and convex laws, are considered. These closure laws describe the speed variation of the hydrogen-natural gas mixture as the valve is closing. The numerical solution is obtained using the reduced order m...

  12. Investigation of a Gamma model for mixture STR samples

    DEFF Research Database (Denmark)

    Christensen, Susanne; Bøttcher, Susanne Gammelgaard; Lauritzen, Steffen L.

    The behaviour of PCR Amplification Kit, when used for mixture STR samples, is investigated. A model based on the Gamma distribution is fitted to the amplifier output for constructed mixtures, and the assumptions of the model is evaluated via residual analysis.......The behaviour of PCR Amplification Kit, when used for mixture STR samples, is investigated. A model based on the Gamma distribution is fitted to the amplifier output for constructed mixtures, and the assumptions of the model is evaluated via residual analysis....

  13. Quantum phases of Fermi-Fermi mixtures in optical lattices

    OpenAIRE

    Iskin, M.; de Melo, C. A. R. Sa

    2007-01-01

    The ground state phase diagram of Fermi-Fermi mixtures in optical lattices is analyzed as a function of interaction strength, population imbalance, filling fraction and tunneling parameters. It is shown that population imbalanced Fermi-Fermi mixtures reduce to strongly interacting Bose-Fermi mixtures in the molecular limit, in sharp contrast to homogeneous or harmonically trapped systems where the resulting Bose-Fermi mixture is weakly interacting. Furthermore, insulating phases are found in ...

  14. Species composition and fire: non-additive mixture effects on ground fuel flammability

    Directory of Open Access Journals (Sweden)

    Cassandra eVan Altena

    2012-04-01

    Full Text Available Biodiversity effects on many aspects of ecosystem function have been well documented. However, fire is an exception: fire experiments have mainly included single species, bulk litter, or vegetation, and, as such, the role of biodiversity as a determinant of flammability, a crucial aspect of ecosystem function, is poorly understood. This study is the first to experimentally test whether flammability characteristics of two-species mixtures are non-additive, i.e. differ from expected flammability based on the component species in monoculture. In standardized fire experiments on ground fuels, including monocultures and mixtures of five contrasting subarctic plant fuel types in a controlled laboratory environment, we measured flame speed, flame duration and maximum temperature. Broadly half of the mixture combinations showed non-additive effects for these flammability indicators; these were mainly enhanced dominance effects, where the fuel types with the more flammable value for a characteristic determined the flammability of the whole mixture. The high incidence of species non-additive effects on ground fuel flammability suggest that the combinations of fuel types may have important effects on ground fire regimes in vegetations differing or changing in species composition.

  15. Evaluation the effect of using polymers on the performance of wearing asphalt mixture

    Directory of Open Access Journals (Sweden)

    Yasir Mohammed Jebur

    2017-03-01

    Full Text Available In Iraq , the increasing in number of vehicles and trucks with their heavy traffic loading and under high temperature , a variety of pavement distresses continues to develop affecting the performance and economy of pavement construction. Polymer modified asphalt mixtures have been used to resist the distresses that produced and developed from the applied stresses. Several distresses effect on the performance of HMA. The primary forms of distress are fatigue cracking , rutting , moisture damage and thermal cracking. These distresses reduce the services life of HMA and increase the maintenance costs. The main objective of this research is to find the effect of polymers on the performance of asphalt mixtureby using one asphalt cement grade (40-50 from Al-Daurah refinery with two types of locally available polymers (Low-Density Polyethylene LDPE and Styrene Butadiene Styrene SBS with three percentages for each type. These percent are (1, 3 and 6 % for (LDPE & SBS by weight of asphalt cement. Each type of these polymers is blended with asphalt cement by using the wet process. The experimental work showed that all polymer-modified mixtures have stability and indirect tensile strength higher than the control mixtures. It can be concluded that the addition of (1% LDPE and (3% SBS to asphalt mixtures showed better improvement on the performance properties of pavement modified with these polymers , in which the referred percent represent the optimum percent of concentration for blending polymers .

  16. PERMEABILITY AND CONSOLIDATION OF SEDIMENT MIXTURES AS FUNCTION OF SAND CONTENT AND CLAY MINERALOGY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The current study is the first step in a systematic experimental research on the erosion behaviour of sand-mud mixtures. It concerns the effect of a varying sand content and clay mineralogy on the porosity, structure, strength and permeability of artificially generated sediment mixtures. The permeability of a sediment mixture is an especially significant parameter concerning the type of erosion that occurs. It determines ifthe erosion of the bed is either a drained or an undrained process,respectively indicating surface erosion or mass erosion. Measurements on various mixtures concerning the consolidation coefficient and the permeability have been executed. Results show a distinct transition of behaviour between a sand-silt dominated network structure and a clay-water matrix. The occurrence of these two types of structures appears to depend on the porosity of the volume fraction of sand related to silt, which is, therefore, an important parameter concerning the type of erosion. Finally, the study provides a valuable data set that can be used as a reference for following stages of this research on the erosion behaviour of natural cohesive sediments.

  17. Investigation of thermal properties of raw materials of asphalt mixtures

    Science.gov (United States)

    Géber, R.; Simon, A.; Kocserha, I.

    2017-02-01

    Asphalt mixtures are composite materials, which are made of different grades of mineral aggregates and bitumen. During the mixing process mineral materials were blended with bitumen at relatively high temperature (∼200 °C). As the binding process come off in these higher temperature range, thermal properties of asphaltic materials are important. The aim of this project is to reveal the thermal properties of raw materials. During our research two types of mineral aggregates were tested (limestone and dolomite) by different methods. Differential thermal analysis, thermal expansion and thermal conductivity were investigated at technologically important temperatures. The results showed that the structure of mineral materials did not change at elevated temperatures, expansion of samples was neglible, while thermal conductivity changed by temperature.

  18. Asphalt Mixture Segregation Detection: Digital Image Processing Approach

    Directory of Open Access Journals (Sweden)

    Mohamadtaqi Baqersad

    2017-01-01

    Full Text Available Segregation determination in the asphalt pavement is an issue causing many disputes between agencies and contractors. The visual inspection method has commonly been used to determine pavement texture and in-place core density test used for verification. Furthermore, laser-based devices, such as the Florida Texture Meter (FTM and the Circular Track Meter (CTM, have recently been developed to evaluate the asphalt mixture texture. In this study, an innovative digital image processing approach is used to determine pavement segregation. In this procedure, the standard deviation of the grayscale image frequency histogram is used to determine segregated regions. Linear Discriminate Analysis (LDA is then implemented on the obtained standard deviations from image processing to classify pavements into the segregated and nonsegregated areas. The visual inspection method is utilized to verify this method. The results have demonstrated that this new method is a robust tool to determine segregated areas in newly paved FC9.5 pavement types.

  19. Continuous mixtures with bathtub-shaped failure rates

    OpenAIRE

    Block, Henry W.; LI, YULIN; Savits, Thomas H.; Wang, Jie

    2008-01-01

    The failure rate of a mixture of even the most standard distributions used in reliability can have a complicated shape. However, failure rates of mixtures of two carefully selected distributions will have the well-known bathtub shape. Here we show that mixtures of whole families of distribtions can have a bathtub-shaped failure rate.

  20. Lessons learned in managing alfalfa-grass mixtures

    Science.gov (United States)

    Grass-alfalfa mixtures have a number of benefits that make them attractive to producers. However, they can be problematic to establish and maintain. Research programs have made progress in understanding the benefits and challenges of alfalfa-grass mixtures. Mixtures may have greater winter survival ...

  1. 40 CFR 721.5769 - Mixture of nitrated alkylated phenols.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mixture of nitrated alkylated phenols... Substances § 721.5769 Mixture of nitrated alkylated phenols. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a mixture of nitrated alkylated...

  2. 21 CFR 864.8625 - Hematology quality control mixture.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hematology quality control mixture. 864.8625 Section 864.8625 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... quality control mixture. (a) Identification. A hematology quality control mixture is a device used...

  3. TEMPERATURE INFLUENCE ON PHASE STABILITY OF ETHANOL-GASOLINE MIXTURES

    Directory of Open Access Journals (Sweden)

    Valerian Cerempei

    2011-06-01

    Full Text Available The article investigates phase stability of ethanol-gasoline mixtures depending on their composition, water concentration in ethanol and ethanol-gasoline mixture and temperature. There have been determined the perfect functioning conditions of spark ignition engines fueled with ethanol-gasoline mixtures.

  4. 46 CFR 154.1735 - Methyl acetylene-propadiene mixture.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Methyl acetylene-propadiene mixture. 154.1735 Section... Operating Requirements § 154.1735 Methyl acetylene-propadiene mixture. (a) The composition of the methyl acetylene-propadiene mixture at loading must be within the following limits or specially approved by...

  5. Dissipation of bentazone, pyrimethanil and boscalid in biochar and digestate based soil mixtures for biopurification systems

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Santanu, E-mail: s.mukherjee@fz-juelich.de [Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Tappe, Wolfgang; Weihermueller, Lutz; Hofmann, Diana; Köppchen, Stephan [Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Laabs, Volker; Schroeder, Tom [BASF SE, Crop Protection, 67117, Limburgerhof (Germany); Vereecken, Harry [Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Burauel, Peter [Sustainable Campus, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany)

    2016-02-15

    Biopurification systems, such as biofilters, are biotechnological tools to prevent point sources of pesticide pollution stemming from on-farm operations. For the purification processes pesticide sorption and mineralization and/or dissipation are essential and both largely depend on the type of filling materials and the pesticide in use. In this paper the mineralization and dissipation of three contrasting {sup 14}C-labeled pesticides (bentazone, boscalid, and pyrimethanil) were investigated in laboratory incubation experiments using sandy soil, biochar produced from Pine woodchips, and/or digestate obtained from anaerobic digestion process using maize silage, chicken manure, beef and pig urine as feedstock. The results indicate that the addition of digestate increased pesticide mineralization, whereby the mineralization was not proportional to the digestate loads in the mixture, indicating a saturation effect in the turnover rate of pesticides. This effect was in correlation with the amount of water extractable DOC, obtained from the digestate based mixtures. Mixing biochar into the soil generally reduced total mineralization and led to larger sorption/sequestration of the pesticides, resulting in faster decrease of the extractable fraction. Also the addition of biochar to the soil/digestate mixtures reduced mineralization compared to the digestate alone mixture but mineralization rates were still higher as for the biochar/soil alone. In consequence, the addition of biochar to the soil generally decreased pesticide dissipation times and larger amounts of biochar led to high amounts of non-extractable residues of pesticide in the substrates. Among the mixtures tested, a mixture of digestate (5%) and biochar (5%) gave optimal results with respect to mineralization and simultaneous sorption for all three pesticides. - Highlights: • Biochar and digestate significantly affects the dissipation pattern of pesticides. • Addition of digestate enhanced mineralization of

  6. Influence of shape and size of the particles on jigging separation of plastics mixture.

    Science.gov (United States)

    Pita, Fernando; Castilho, Ana

    2016-02-01

    Plastics are popular for numerous applications due to their high versatility and favourable properties such as endurance, lightness and cheapness. Therefore the generation of plastic waste is constantly increasing, becoming one of the larger categories in municipal solid waste. Almost all plastic materials are recyclable, but for the recycling to be possible it is necessary to separate the different types of plastics. The aim of this research was to evaluate the performance of the jig separation of bi-component plastic mixtures. For this study six granulated plastics had been used: Polystyrene (PS), Polymethyl methacrylate (PMMA), Polyethylene Terephthalate (PET-S, PET-D) and Polyvinyl Chloride (PVC-M, PVC-D). Plastics mixtures were subjected to jigging in a laboratorial Denver mineral jig. The results showed that the quality of the jigging separation varies with the mixture, the density differences and with the size and shape of the particles. In the case of particles with more regular shapes the quality of separation of bi-component plastic mixtures improved with the increase of the particle size. For lamellar particles the influence of particle size was minimal. In general, the beneficiation of plastics with similar densities was not effective, since the separation efficiency was lower than 25%. However, in bi-component plastic mixtures that join a low density plastic (PS) with a high density one (PMMA, PET-S, PET-D, PVC-M and PVC-D), the quality of the jigging separation was greatly improved. The PS grade in the sunk was less than 1% for all the plastic mixtures. Jigging proved to be an effective method for the separation of bi-component plastic mixtures. Jigging separation will be enhanced if the less dense plastic, that overflows, has a lamellar shape and if the denser plastic, that sinks, has a regular one.

  7. Mixtures of protic ionic liquids and molecular cosolvents: a molecular dynamics simulation.

    Science.gov (United States)

    Docampo-Álvarez, Borja; Gómez-González, Víctor; Méndez-Morales, Trinidad; Carrete, Jesús; Rodríguez, Julio R; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

    2014-06-07

    In this work, the effect of molecular cosolvents (water, ethanol, and methanol) on the structure of mixtures of these compounds with a protic ionic liquid (ethylammonium nitrate) is analyzed by means of classical molecular dynamics simulations. Included are as-yet-unreported measurements of the densities of these mixtures, used to test our parameterized potential. The evolution of the structure of the mixtures throughout the concentration range is reported by means of the calculation of coordination numbers and the fraction of hydrogen bonds in the system, together with radial and spatial distribution functions for the various molecular species and molecular ions in the mixture. The overall picture indicates a homogeneous mixing process of added cosolvent molecules, which progressively accommodate themselves in the network of hydrogen bonds of the protic ionic liquid, contrarily to what has been reported for their aprotic counterparts. Moreover, no water clustering similar to that in aprotic mixtures is detected in protic aqueous mixtures, but a somehow abrupt replacing of [NO3](-) anions in the first hydration shell of the polar heads of the ionic liquid cations is registered around 60% water molar concentration. The spatial distribution functions of water and alcohols differ in the coordination type, since water coordinates with [NO3](-) in a bidentate fashion in the equatorial plane of the anion, while alcohols do it in a monodentate fashion, competing for the oxygen atoms of the anion. Finally, the collision times of the different cosolvent molecules are also reported by calculating their velocity autocorrelation functions, and a caging effect is observed for water molecules but not in alcohol mixtures.

  8. On the equivalence between kernel self-organising maps and self-organising mixture density networks.

    Science.gov (United States)

    Yin, Hujun

    2006-01-01

    The kernel method has become a useful trick and has been widely applied to various learning models to extend their nonlinear approximation and classification capabilities. Such extensions have also recently occurred to the Self-Organising Map (SOM). In this paper, two recently proposed kernel SOMs are reviewed, together with their link to an energy function. The Self-Organising Mixture Network is an extension of the SOM for mixture density modelling. This paper shows that with an isotropic, density-type kernel function, the kernel SOM is equivalent to a homoscedastic Self-Organising Mixture Network, an entropy-based density estimator. This revelation on the one hand explains that kernelising SOM can improve classification performance by acquiring better probability models of the data; but on the other hand it also explains that the SOM already naturally approximates the kernel method.

  9. Theoretical study of miscibility and glass-forming trends in mixtures of polystyrene spheres

    Science.gov (United States)

    Shih, W.-H.; Stroud, D.

    1984-01-01

    A theoretical study of glass-forming trends and miscibility in mixtures of polystyrene spheres (polyballs) of different diameters, suspended in an aqueous solution, is presented. The polyballs are assumed to be charged and to interact via a Debye-Hueckel screened Coulomb potential. The Helmholtz free energy is calculated from a variational principle based on the Gibbs-Bogoliubov inequality, in which a mixture of hard spheres of different diameters is chosen as the reference system. It is found that when the charges of the two types of polyballs are sufficiently different, the variationally determined ratio of hard-sphere diameters differs substantially, leading to packing difficulties characteristic of glass formation. The experimentally observed range of glass formation corresponds to a ratio of hard-sphere diameters of 0.8 or less. Calculations of the free energy as a function of concentration indicate that the liquid polyball mixture is stable against the phase separation, even for widely different polyball charges.

  10. Mixture approach for optimizing lycopene extraction from tomato and tomato products.

    Science.gov (United States)

    Periago, María Jesús; Rincón, Francisco; Agüera, Maria Dolores; Ros, Gaspar

    2004-09-22

    A simple mixture process design based on the comparison of both quadratic and special cubic models and involving three mixture components (hexane/acetone/ethanol) as a solution for extracting lycopene from raw tomato, tomato sauce, and tomato paste was used to confirm the hypothesis that lycopene extraction rates are a function of the solvent used during the extraction process. Conventional criteria (p lycopene extraction was hexane, there was a positive secondary synergistic interaction of hexane with ethanol (all sample types) and with acetone (tomato paste samples); this suggests that a mixture including all three components is essential for optimizing the extraction process. The partial special cubic model yielded three stationary points, indicating the concentrations of hexane, acetone, and ethanol required to optimize lycopene extraction in raw tomato, tomato sauce, and paste.

  11. Effect of Gas Mixture Composition on the Parameters of an Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Andrej Chríbik

    2012-01-01

    Full Text Available This paper deals with the use of the internal combustion piston engine, which is a drive unit for micro-cogeneration units. The introduction is a brief statement of the nature of gas mixture compositions that are useful for the purposes of combustion engines, together with the basic physical and chemical properties relevant to the burning of this gas mixture. Specifically, we will discuss low-energy gases (syngases and mixtures of natural gas with hydrogen. The second section describes the conversion of the Lombardini LGW 702 combustion engine that is necessary for these types of combustion gases. Before the experimental measurements, a simulation in the Lotus Engine simulation program was carried out to make a preliminary assessment of the impact on the performance of an internal combustion engine. The last section of the paper presents the experimental results of partial measurements of the performance and emission parameters of an internal combustion engine powered by alternative fuels.

  12. Y-STR analysis on DNA mixture samples--results of a collaborative project of the ENFSI DNA Working Group

    DEFF Research Database (Denmark)

    Parson, Walther; Niederstätter, Harald; Lindinger, Alexandra;

    2008-01-01

    The ENFSI (European Network of Forensic Science Institutes) DNA Working Group undertook a collaborative project on Y-STR typing of DNA mixture samples that were centrally prepared and thoroughly tested prior to the shipment. Four commercial Y-STR typing kits (Y-Filer, Applied Biosystems, Foster C...

  13. The optimization of concrete mixtures for use in highway applications

    Science.gov (United States)

    Moini, Mohamadreza

    grading, coarseness chart) were studied and compared to aggregate packing results and performance of experimented concrete mixtures; • Optimal aggregate blends were selected and used for concrete mixtures; • The optimal dosage of admixtures were selected for three types of plasticizing and superplasticizing admixtures based on a separately conducted study; • The SCM dosages were selected based on current WisDOT specifications; • The optimal air-entraining admixture dosage was investigated based on performance of preliminary concrete mixtures; • Finally, optimal concrete mixtures were tested for fresh properties, compressive strength development, modulus of rupture, at early ages (1day) and ultimate ages (360 days). • Durability performance indicators for optimal concrete mixtures were also tested for resistance of concrete to rapid chloride permeability (RCP) at 30 days and 90 days and resistance to rapid freezing and thawing at 56 days.

  14. [Comparison of two spectral mixture analysis models].

    Science.gov (United States)

    Wang, Qin-Jun; Lin, Qi-Zhong; Li, Ming-Xiao; Wang, Li-Ming

    2009-10-01

    A spectral mixture analysis experiment was designed to compare the spectral unmixing effects of linear spectral mixture analysis (LSMA) and constraint linear spectral mixture analysis (CLSMA). In the experiment, red, green, blue and yellow colors were printed on a coarse album as four end members. Thirty nine mixed samples were made according to each end member's different percent in one pixel. Then, field spectrometer was located on the top of the mixed samples' center to measure spectrum one by one. Inversion percent of each end member in the pixel was extracted using LSMA and CLSMA models. Finally, normalized mean squared error was calculated between inversion and real percent to compare the two models' effects on spectral unmixing. Results from experiment showed that the total error of LSMA was 0.30087 and that of CLSMA was 0.37552 when using all bands in the spectrum. Therefore, LSMA was 0.075 less than that of CLSMA when the whole bands of four end members' spectra were used. On the other hand, the total error of LSMA was 0.28095 and that of CLSMA was 0.29805 after band selection. So, LSMA was 0.017 less than that of CLSMA when bands selection was performed. Therefore, whether all or selected bands were used, the accuracy of LSMA was better than that of CLSMA because during the process of spectrum measurement, errors caused by instrument or human were introduced into the model, leading to that the measured data could not mean the strict requirement of CLSMA and therefore reduced its accuracy: Furthermore, the total error of LSMA using selected bands was 0.02 less than that using the whole bands. The total error of CLSMA using selected bands was 0.077 less than that using the whole bands. So, in the same model, spectral unmixing using selected bands to reduce the correlation of end members' spectra was superior to that using the whole bands.

  15. CLASSIFICATION OF TECHNICAL MEANS FOR PREPARATION AND DISTRIBUTION OF FEED MIXTURES AT SMALL CATTLE FARMS

    Directory of Open Access Journals (Sweden)

    Frolov V. Y.

    2015-12-01

    Full Text Available To increase the productivity of the cattle it is demanded simultaneous distribution of all types of animal feed in the form of balanced feed mixture with a given nutritional value. Balanced feeding of animals can improve their productivity, reduce feed wastage, and include alternative components of feed mixtures in their diets, which have nourishing properties and high digestibility; make and adjust feeding rations. Researches conducted by Russian and foreign scientists, proved the prospects of full feeding of complete feed mixtures, which allow to increase the productivity of animals to 9-30 % and reduce the feed consumption in the calculation of 1 с of milk by 7-8 %. The composition of complete feed mixtures includes sunflower cake, silage, root crops and forage. The process of preparation and distribution of feeds for large horned livestock is the issue of all the necessary components of the feed mixture with a given nutritional value. Saturation of the feed product with extra energy goes during its interaction with the working bodies of technical means for preparation and distribution (TMPD of different types of food. For preparation and distribution of components of the feed mixture it is necessary to have following facilities, provided with reducing energy intensity and improving the qualitative indicators of processes: for grinding beet fodder and sunflower cake we need disk shredders; for shredding silage and roughage – bearnie and rotor shredders, respectively; for dispensing of beet fodder and sunflower cake – belt conveyor, for dispensing silage and roughage we use disc and drum dispensers, respectively; for mixing sunflower cake - rotary mixers, and for silage, beet fodder and for-age we may use paddle mixers; for distribution of sunflower cake we use rotary feeders, for silage and beet fodder – bin distributors, and for coarse feed we should use conveyor dispensers

  16. Electrical signatures of ethanol-liquid mixtures: implications for monitoring biofuels migration in the subsurface

    Science.gov (United States)

    Personna, Yves Robert; Slater, Lee; Ntarlagiannis, Dimitrios; Werkema, Dale; Szabo, Zoltan

    2013-01-01

    Ethanol (EtOH), an emerging contaminant with potential direct and indirect environmental effects, poses threats to water supplies when spilled in large volumes. A series of experiments was directed at understanding the electrical geophysical signatures arising from groundwater contamination by ethanol. Conductivity measurements were performed at the laboratory scale on EtOH–water mixtures (0 to 0.97 v/v EtOH) and EtOH–salt solution mixtures (0 to 0.99 v/v EtOH) with and without a sand matrix using a conductivity probe and a four-electrode electrical measurement over the low frequency range (1–1000 Hz). A Lichtenecker–Rother (L–R) type mixing model was used to simulate electrical conductivity as a function of EtOH concentration in the mixture. For all three experimental treatments increasing EtOH concentration resulted in a decrease in measured conductivity magnitude (|σ|). The applied L–R model fitted the experimental data at concentration ≤ 0.4 v/v EtOH, presumably due to predominant and symmetric intermolecular (EtOH–water) interaction in the mixture. The deviation of the experimental |σ| data from the model prediction at higher EtOH concentrations may be associated with hydrophobic effects of EtOH–EtOH interactions in the mixture. The |σ| data presumably reflected changes in relative strength of the three types of interactions (water–water, EtOH–water, and EtOH–EtOH) occurring simultaneously in EtOH–water mixtures as the ratio of EtOH to water changed. No evidence of measurable polarization effects at the EtOH–water and EtOH–water–mineral interfaces over the investigated frequency range was found. Our results indicate the potential for using electrical measurements to characterize and monitor EtOH spills in the subsurface.

  17. Antileishmanial activity of a mixture of Tridax procumbens and Allium sativum in mice

    Directory of Open Access Journals (Sweden)

    Gamboa-Leon Rubi

    2014-01-01

    Full Text Available We tested a mixture of Tridax procumbens, known for its direct action against Leishmania mexicana, and Allium sativum, known for its immunomodulatory effect, as an alternative to treat cutaneous leishmaniasis. Acute oral toxicity was tested with the Up-and-Down Procedure (UDP using a group of healthy mice administered with either T. procumbens or A. sativum extracts and compared with a control group. Liver injury and other parameters of toxicity were determined in mice at day 14. The in vivo assay was performed with mice infected with L. mexicana promastigotes and treated with either a mixture of T. procumbens and A. sativum or each extract separately. The thickness of the mice’s footpads was measured weekly. After the 12-week period of infection, blood samples were obtained by cardiac puncture to determine the total IgG, IgG1 and IgG2a immunoglobulins by a noncommercial indirect ELISA. We showed that the mixture of T. procumbens and A. sativum extracts was better at controlling L. mexicana infection while not being toxic when tested in the acute oral toxicity assay in mice. An increase in the ratio of IgG2a/IgG1 indicated a tendency to raise a Th1-type immune response in mice treated with the mixture. The mixture of T. procumbens and A. sativum extracts is a promising natural treatment for cutaneous leishmaniasis and its healing effects make it a good candidate for a possible new phytomedicine.

  18. Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol–methanol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

    2014-12-15

    Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.

  19. Molecular simulation study of adsorption and diffusion on silicalite for a benzene/CO2 mixture.

    Science.gov (United States)

    Yue, Xiaopeng; Yang, Xiaoning

    2006-03-28

    The adsorption and diffusion of a binary mixture of supercritical CO2 and benzene on silicalite (MFI-type) have been studied through the grand canonical Monte Carlo and molecular dynamics (MD) simulations. The adsorption behavior of pure CO2 on silicalite was discussed in detail from the adsorption isotherms, adsorption sites, interaction energies, and isosteric heats of adsorption. For the mixture, the influences of temperature, pressure and composition on the adsorption isotherms have been examined. The adsorption site behavior of the mixture has been analyzed, and benzene molecules get adsorbed preferentially in the more spacious channel intersection positions. These simulation results suggest that SC-CO2 fluid can be used as an efficient desorbent of larger aromatics in the zeolite material. The diffusion characteristic for the benzene/CO2 mixture was studied on the basis of MD simulation. It was found that the large coadsorbed benzene molecule has a pronounced effect on the CO2 diffusion in the mixture, while the mobility of benzene molecules is very small due to geometrical restrictions.

  20. Antileishmanial activity of a mixture of Tridax procumbens and Allium sativum in mice.

    Science.gov (United States)

    Gamboa-Leon, Rubi; Vera-Ku, Marina; Peraza-Sanchez, Sergio R; Ku-Chulim, Carlos; Horta-Baas, Aurelio; Rosado-Vallado, Miguel

    2014-01-01

    We tested a mixture of Tridax procumbens, known for its direct action against Leishmania mexicana, and Allium sativum, known for its immunomodulatory effect, as an alternative to treat cutaneous leishmaniasis. Acute oral toxicity was tested with the Up-and-Down Procedure (UDP) using a group of healthy mice administered with either T. procumbens or A. sativum extracts and compared with a control group. Liver injury and other parameters of toxicity were determined in mice at day 14. The in vivo assay was performed with mice infected with L. mexicana promastigotes and treated with either a mixture of T. procumbens and A. sativum or each extract separately. The thickness of the mice's footpads was measured weekly. After the 12-week period of infection, blood samples were obtained by cardiac puncture to determine the total IgG, IgG1 and IgG2a immunoglobulins by a noncommercial indirect ELISA. We showed that the mixture of T. procumbens and A. sativum extracts was better at controlling L. mexicana infection while not being toxic when tested in the acute oral toxicity assay in mice. An increase in the ratio of IgG2a/IgG1 indicated a tendency to raise a Th1-type immune response in mice treated with the mixture. The mixture of T. procumbens and A. sativum extracts is a promising natural treatment for cutaneous leishmaniasis and its healing effects make it a good candidate for a possible new phytomedicine.

  1. Study on triaxial test method and failure criterion of asphalt mixture

    Directory of Open Access Journals (Sweden)

    Jianlong Zheng

    2015-04-01

    Full Text Available Asphalt mixture is the most widely used pavement material all over the world. In China, more than 90% of service expressways are asphalt pavement. However, current asphalt pavement design method still has irrationality. Even though maximum tensile stress theory is used as failure criterion, pavement structure under the effects of wheel load is in three-dimensional complex stress state. Obviously, one-dimensional strength theory cannot reflect the failure characteristics and the resistance of pavement structure. So it is necessary to study the failure criterion of asphalt mixture under three-dimensional complex stress state. Due to limitations of test equipment, there are almost no studies in related area. Under this background, this paper develops a new triaxial test method, according to the investigation of strength characteristics of asphalt mixture under complex stress state through plane isobaric/axial tensile test, plane isobaric/axial compression test, plane tensile and compression/axial tensile test, to reveal the general rules of asphalt mixture's strength failure. The failure mode is divided into three types: tensile failure, shear failure and rheological failure. The tensile meridian and compression meridian in the stress space and strength envelope in the π plane where hydrostatic pressure is greater than zero are obtained, and the failure criterion of asphalt mixture under complex stress state is established, providing theoretical method and scientific basis for structure design as well as strength check of asphalt pavement under three-dimensional stress state.

  2. Dynamic mean field theory for lattice gas models of fluid mixtures confined in mesoporous materials.

    Science.gov (United States)

    Edison, J R; Monson, P A

    2013-11-12

    We present the extension of dynamic mean field theory (DMFT) for fluids in porous materials (Monson, P. A. J. Chem. Phys. 2008, 128, 084701) to the case of mixtures. The theory can be used to describe the relaxation processes in the approach to equilibrium or metastable equilibrium states for fluids in pores after a change in the bulk pressure or composition. It is especially useful for studying systems where there are capillary condensation or evaporation transitions. Nucleation processes associated with these transitions are emergent features of the theory and can be visualized via the time dependence of the density distribution and composition distribution in the system. For mixtures an important component of the dynamics is relaxation of the composition distribution in the system, especially in the neighborhood of vapor-liquid interfaces. We consider two different types of mixtures, modeling hydrocarbon adsorption in carbon-like slit pores. We first present results on bulk phase equilibria of the mixtures and then the equilibrium (stable/metastable) behavior of these mixtures in a finite slit pore and an inkbottle pore. We then use DMFT to describe the evolution of the density and composition in the pore in the approach to equilibrium after changing the state of the bulk fluid via composition or pressure changes.

  3. Thermodynamic perturbation theory for self-assembling mixtures of divalent single patch colloids.

    Science.gov (United States)

    Marshall, Bennett D; Chapman, Walter G

    2014-07-28

    In this work we extend Wertheim's thermodynamic perturbation theory (TPT) to binary mixtures (species A and species B) of patchy colloids were each species has a single patch which can bond a maximum of twice (divalent). Colloids are treated as hard spheres with a directional conical association site. We restrict the system such that only patches between unlike species share attractions; meaning there are AB attractions but no AA or BB attractions. The theory is derived in Wertheim's two density formalism for one site associating fluids. Since the patches are doubly bondable, associated chains, of all chain lengths, as well as 4-mer rings consisting of two species A and two species B colloids are accounted for. With the restriction of only AB attractions, triatomic rings of doubly bonded colloids, which dominate in the corresponding pure component case, cannot form. The theory is shown to be in good agreement with Monte Carlo simulation data for the structure and thermodynamics of these patchy colloid mixtures as a function of temperature, density, patch size and composition. It is shown that 4-mer rings dominate at low temperature, inhibiting the polymerization of the mixture into long chains. Mixtures of this type have been recently synthesized by researchers. This work provides the first theory capable of accurately modeling these mixtures.

  4. Phase Diagrams and Ordering in Charged Membranes: Binary Mixtures of Charged and Neutral Lipids.

    Science.gov (United States)

    Shimokawa, Naofumi; Himeno, Hiroki; Hamada, Tsutomu; Takagi, Masahiro; Komura, Shigeyuki; Andelman, David

    2016-07-07

    We propose a model describing the phase behavior of two-component membranes consisting of binary mixtures of electrically charged and neutral lipids. We take into account the structural phase transition (main-transition) of the hydrocarbon chains, and investigate the interplay between this phase transition and the lateral phase separation. The presence of charged lipids significantly affects the phase behavior of the multicomponent membrane. Due to the conservation of lipid molecular volume, the main-transition temperature of charged lipids is lower than that of neutral ones. Furthermore, as compared with binary mixtures of neutral lipids, the membrane phase separation in binary mixtures of charged lipids is suppressed, in accord with recent experiments. We distinguish between two types of charged membranes: mixtures of charged saturated lipid/neutral unsaturated lipid and a second case of mixtures of neutral saturated lipid/charged unsaturated lipid. The corresponding phase behavior is calculated and shown to be very different. Finally, we discuss the effect of added salt on the phase separation and the temperature dependence of the lipid molecular area.

  5. Temperature relaxation in dense plasma mixtures

    Science.gov (United States)

    Faussurier, Gérald; Blancard, Christophe

    2016-09-01

    We present a model to calculate temperature-relaxation rates in dense plasma mixtures. The electron-ion relaxation rates are calculated using an average-atom model and the ion-ion relaxation rates by the Landau-Spitzer approach. This method allows the study of the temperature relaxation in many-temperature electron-ion and ion-ion systems such as those encountered in inertial confinement fusion simulations. It is of interest for general nonequilibrium thermodynamics dealing with energy flows between various systems and should find broad use in present high energy density experiments.

  6. Gaussian mixture model of heart rate variability.

    Directory of Open Access Journals (Sweden)

    Tommaso Costa

    Full Text Available Heart rate variability (HRV is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters.

  7. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    Robert De Levie

    2009-09-01

    The spectrometric analysis of a mixture of two chemically and spectroscopically similar compounds is illustrated for the simultaneous spectrometric determination of caffeine and theobromine, the primary stimulants in coffee and tea, based on their ultraviolet absorbances. Their analysis indicates that such measurements may need an unexpectedly high precision to yield accurate answers, because of an artifact of inverse cancellation, in which a small noise or drift signal is misinterpreted in terms of a concentration difference. The computed sum of the concentrations is not affected.

  8. Bayesian mixture models for partially verified data

    DEFF Research Database (Denmark)

    Kostoulas, Polychronis; Browne, William J.; Nielsen, Søren Saxmose;

    2013-01-01

    for some individuals, in order to minimize this loss in the discriminatory power. The distribution of the continuous antibody response against MAP has been obtained for healthy, MAP-infected and MAP-infectious cows of different age groups. The overall power of the milk-ELISA to discriminate between healthy......Bayesian mixture models can be used to discriminate between the distributions of continuous test responses for different infection stages. These models are particularly useful in case of chronic infections with a long latent period, like Mycobacterium avium subsp. paratuberculosis (MAP) infection...

  9. Two-microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    2006-01-01

    of Speech Mixtures," 2006, submited for journal publication. See also, [2] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: "Overcomplete Blind Source Separation by Combining ICA and Binary Time-Frequency Masking," in proceedings of IEEE International workshop on Machine Learning......In this demonstration we show the separation of 3-7 mixed speech sources based on information from two microphones. Separation with background noise is demonstrated too. The algorithms are described in 1] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: "Two-microphone Separation...

  10. Video compressive sensing using Gaussian mixture models.

    Science.gov (United States)

    Yang, Jianbo; Yuan, Xin; Liao, Xuejun; Llull, Patrick; Brady, David J; Sapiro, Guillermo; Carin, Lawrence

    2014-11-01

    A Gaussian mixture model (GMM)-based algorithm is proposed for video reconstruction from temporally compressed video measurements. The GMM is used to model spatio-temporal video patches, and the reconstruction can be efficiently computed based on analytic expressions. The GMM-based inversion method benefits from online adaptive learning and parallel computation. We demonstrate the efficacy of the proposed inversion method with videos reconstructed from simulated compressive video measurements, and from a real compressive video camera. We also use the GMM as a tool to investigate adaptive video compressive sensing, i.e., adaptive rate of temporal compression.

  11. Molecular weight scaling in critical polymer mixtures

    DEFF Research Database (Denmark)

    Gehlsen, M.D.; Rosedale, J.R.; Bates, F.S.

    1992-01-01

    , DELTA-X(D), and molecular weight by small-angle neutron scattering. The critical point for demixing was determined to scale as chi(eff,c) is similar to N(-delta) with delta = 1.01 +/- 0.05, where N is the degree of polymerization. This result confirms the mean-field prediction of Flory and Huggins.......Symmetric binary mixtures of partially deuterated polymers were prepared at the critical composition. The segment-segment interaction energy parameter chi(eff) was varied by adjusting the difference in deuterium content DELTA-X(D) between species. Chi(eff) was measured as a function of temperature...

  12. The Precise Measurement of Vapor-Liquid Equilibrium Properties of the CO2/Isopentane Binary Mixture, and Fitted Parameters for a Helmholtz Energy Mixture Model

    Science.gov (United States)

    Miyamoto, H.; Shoji, Y.; Akasaka, R.; Lemmon, E. W.

    2017-10-01

    Natural working fluid mixtures, including combinations of CO2, hydrocarbons, water, and ammonia, are expected to have applications in energy conversion processes such as heat pumps and organic Rankine cycles. However, the available literature data, much of which were published between 1975 and 1992, do not incorporate the recommendations of the Guide to the Expression of Uncertainty in Measurement. Therefore, new and more reliable thermodynamic property measurements obtained with state-of-the-art technology are required. The goal of the present study was to obtain accurate vapor-liquid equilibrium (VLE) properties for complex mixtures based on two different gases with significant variations in their boiling points. Precise VLE data were measured with a recirculation-type apparatus with a 380 cm3 equilibration cell and two windows allowing observation of the phase behavior. This cell was equipped with recirculating and expansion loops that were immersed in temperature-controlled liquid and air baths, respectively. Following equilibration, the composition of the sample in each loop was ascertained by gas chromatography. VLE data were acquired for CO2/ethanol and CO2/isopentane binary mixtures within the temperature range from 300 K to 330 K and at pressures up to 7 MPa. These data were used to fit interaction parameters in a Helmholtz energy mixture model. Comparisons were made with the available literature data and values calculated by thermodynamic property models.

  13. Prediction of saturated liquid enthalpy of refrigerant mixtures

    Institute of Scientific and Technical Information of China (English)

    CHEN ZeShao; CHEN JianXin; HU Peng

    2007-01-01

    New corresponding temperature and corresponding enthalpy of refrigerant mixtures were defined. The relationship between saturated liquid corresponding enthalpy and corresponding temperature of refrigerant mixtures accorded with that of pure components. The characteristic parameters of saturated liquid enthalpy difference of refrigerant mixtures were calculated by three methods according to the different application conditions. The generalized equation of saturated liquid enthalpy of refrigerant mixtures was presented. The calculated values were compared with the values in literature for five ternary and binary refrigerant mixtures, namely R404A, R407A, R407B, R32/R134a, and R410A. The overall average absolute deviation was less than 1.0%.

  14. Investigation of Adding Proportion of RAP in Recycled Asphalt Mixture

    Directory of Open Access Journals (Sweden)

    Cao He

    2016-01-01

    Full Text Available According to the relationship between gradation and proportion of Reclaimed Asphalt Pavement (RAP and design gradation of recycled mixture, the authors discussed the influence of proportion of RAP on gradation adjustment of recycled mixture. And then, recycled mixture with 0%, 30%, 50%, 70% of RAP were made, and Influence of proportion of RAP on high and low temperature performance, water stability and anti-aging performance of recycled mixture were discussed. The results and analysis indicate that gradation of recycled mixture would not be adjusted to aiming gradation if proportion of RAP was too big. With the increase of proportion of RAP, high temperature performance and anti-aging performance of recycled mixture enhanced, but low temperature performance and water stability decayed sharply. In practical application, reasonable proportion of RAP should be determined according to gradation, performance demand and economy of recycled mixture.

  15. Systems and methods for removing components of a gas mixture

    Science.gov (United States)

    None

    2016-09-06

    A system for removing components of a gaseous mixture is provided comprising: a reactor fluid containing vessel having conduits extending therefrom, aqueous fluid within the reactor, the fluid containing a ligand and a metal, and at least one reactive surface within the vessel coupled to a power source. A method for removing a component from a gaseous mixture is provided comprising exposing the gaseous mixture to a fluid containing a ligand and a reactive metal, the exposing chemically binding the component of the gaseous mixture to the ligand. A method of capturing a component of a gaseous mixture is provided comprising: exposing the gaseous mixture to a fluid containing a ligand and a reactive metal, the exposing chemically binding the component of the gaseous mixture to the ligand, altering the oxidation state of the metal, the altering unbinding the component from the ligand, and capturing the component.

  16. Health and environmental effects of complex chemical mixtures: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The Office of Health and Environmental Research (OHER) of the Department of Energy supports a broad long-term research program on human health and environmental effects from potential exposure to energy-related complex chemical mixtures. The program seeks basic mechanistic data on the effects of complex mixtures at the cellular, molecular, and whole animal levels to aid in predicting human health effects and seeks ecological data on biological and physical transformations in the mixtures, concentrations of the mixtures in various compartments of the environment, and potential routes for human exposure to these mixtures (e.g., food chain). On June 17-18, 1985, OHER held its First Annual Technical Meeting on the Complex Chemical Mixtures Program in Chicago, IL. The primary purpose of the meeting was to enable principal investigators to report the research status and accomplishments of ongoing complex chemical mixture studies supported by OHER. To help focus future research directions round table discussions were conducted.

  17. A simple mixture to enhance muscle transmittance

    Science.gov (United States)

    Oliveira, Luís; Lage, Armindo; Clemente, Manuel Pais; Tuchin, Valery V.

    2008-06-01

    Skeletal muscle is a fibrous tissue composed by muscle fibers and interstitial fluid. Due to this constitution, the muscle presents a non uniform refractive index profile that origins strong light scattering. One way to improve tissue transmittance is to reduce this refractive index mismatch by immersing the muscle in an optical clearing agent. As a consequence of such immersion tissue also suffers dehydration. The study of the optical clearing effect created by a simple mixture composed by ethanol, glycerol and distilled water has proven its effectiveness according to the variations observed in the parameters under study. The effect was characterized in terms of its magnitude, time duration and histological variations. The applied treatment has created a small reduction of the global sample refractive index that is justified by the long time rehydration caused by water in the immersing solution. From the reduction in sample pH we could also identify the dehydration process created in the sample. The immersion treatment has originated fiber bundle contraction and a spread distribution of the muscle fiber bundles inside. New studies with the mixture used, or with other combinations of its constituents might be interesting to perform with the objective to develop new clinical procedures.

  18. Non-equilibrium properties of hadronic mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Prakasch, Madappa (State Univ. of New York, Stony Brook, NY (United States). Physics Dept.); Prakasch, Manju (State Univ. of New York, Stony Brook, NY (United States). Physics Dept.); Venugopalan, R. (State Univ. of New York, Stony Brook, NY (United States). Physics Dept.); Welke, G. (Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.)

    1993-05-01

    The equilibration of hot hadronic matter is studied in the framework of relativistic kinetic theory. Various non-equilibrium properties of a mixture comprised of pions, kaons and nucleons are calculated in the dilute limit for small deviations from local thermal equilibrium. Interactions between these constituents are specified through the empirical phase shifts. The properties calculated include the relaxation/collision times, momentum and energy persistence ratios in elastic collisions, and transport properties such as the viscosity, the thermal conductivity, and the diffusion and thermal diffusion coefficients. The Chapman-Enskog formalism is extended to extract relaxation times associated with shear and heat flows, and drag and diffusion flows in a mixture. The equilibrium number concentration of the constituents is chosen to mimic those expected in the mid-rapidity interval of CERN and RHIC experiments. In this case, kaons and nucleons are found to equilibrate significantly more slowly than pions. These results shed new light on the influence of collective flow effects on the transverse momentum distributions of kaons and nucleons versus those of pions in ultra-relativistic nuclear collisions. (orig.)

  19. Spinodal Decomposition in Mixtures Containing Surfactants

    Science.gov (United States)

    Melenekvitz, J.

    1998-03-01

    Spinodal decomposition in mixtures containing two immiscible liquids (A and B) plus surfactant was investigated using a recently developed (J. Melenkevitz and S. H. Javadpour, J. Chem. Phys., 107, 623 (1997).) 3-component Ginzburg-Landau model. The time dependent Ginzburg-Landau (TDGL) equations governing the evolution of structure were numerically integrated in 2-dimensions. We found the growth rate of the average domain size, R(t), decreased with increasing surfactant concentration over a wide range of relative amounts of A and B. This can be attributed to the surfactant accumulating at the growing interface between the immiscible liquids, which leads to a reduction in the surface tension. At late times, the growth rate was noticeably altered when thermal fluctuations were added to the numerical simulations. In this case, power law behavior was observed for R(t) at late times, R(t) ~ t^α, with the exponent α decreasing as the amount of surfactant increased. The dynamics at early times were determined by linearizing the TDGL equations about a uniformly mixed state. The growth rate at ealry times was found to be strongly dependent on the model parameters describing the surfactant miscibility in A and B and the surfactant strength. Comparison with recent measurements on SBR / PB mixtures with added PB-SBR diblock copolymer will also be presented.

  20. A mixture approach to vagueness and ambiguity.

    Directory of Open Access Journals (Sweden)

    Steven Verheyen

    Full Text Available When asked to indicate which items from a set of candidates belong to a particular natural language category inter-individual differences occur: Individuals disagree which items should be considered category members. The premise of this paper is that these inter-individual differences in semantic categorization reflect both ambiguity and vagueness. Categorization differences are said to be due to ambiguity when individuals employ different criteria for categorization. For instance, individuals may disagree whether hiking or darts is the better example of sports because they emphasize respectively whether an activity is strenuous and whether rules apply. Categorization differences are said to be due to vagueness when individuals employ different cut-offs for separating members from non-members. For instance, the decision to include hiking in the sports category or not, may hinge on how strenuous different individuals require sports to be. This claim is supported by the application of a mixture model to categorization data for eight natural language categories. The mixture model can identify latent groups of categorizers who regard different items likely category members (i.e., ambiguity with categorizers within each of the groups differing in their propensity to provide membership responses (i.e., vagueness. The identified subgroups are shown to emphasize different sets of category attributes when making their categorization decisions.

  1. Transport and radiation in complex LTE mixtures

    Science.gov (United States)

    Janssen, Jesper; Peerenboom, Kim; Suijker, Jos; Gnybida, Mykhailo; van Dijk, Jan

    2014-10-01

    Complex LTE mixtures are for example encountered in re-entry, welding, spraying and lighting. These mixtures typically contain a rich chemistry in combination with large temperature gradients. LTE conditions are also interesting because they can aid in the validation of NLTE algorithms. An example is the calculation of transport properties. In this work a mercury free high intensity discharge lamp is considered. The investigation focusses on using salts like InI or SnI as a buffer species. By using these species a dominant background gas like mercury is no longer present. As a consequence the diffusion algorithms based on Fick's law are no longer applicable and the Stefan-Maxwell equations must be solved. This system of equations is modified with conservation rules to set a coldspot pressure for saturated species and enforce the mass dosage for unsaturated species. The radiative energy transport is taken into account by raytracing. Quantum mechanical simulations have been used to calculate the potential curves and the transition dipole moments for indium with iodine and tin with iodine. The results of these calculations have been used to predict the quasistatic broadening by iodine. The work was supported by the project SCHELP from the Belgium IWT (Project Number 110003) and the CATRENE SEEL Project (CA502).

  2. Foaming characteristics of refigerant/lubricant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, D.Y.; Shah, D.O.; Jotshi, C.K.; Bhagwat, S.; Leung, M.; Gregory, A.

    1997-04-01

    The air-conditioning and refrigeration industry has moved to HFC refrigerants which have zero ozone depletion and low global warming potential due to regulations on CFC and HCFC refrigerants and concerns for the environment. The change in refrigerants has prompted the switch from mineral oil and alkylbenzene lubricants to polyolester-based lubricants. This change has also brought about a desire for lubricant, refrigerant and compressor manufacturers to understand the foaming properties of alternative refrigerant/ lubricant mixtures, as well as the mechanisms which affect these properties. The objectives of this investigation are to experimentally determine the foaming absorption and desorption rates of HFC and blended refrigerants in polyolester lubricant and to define the characteristics of the foam formed when the refrigerant leaves the refrigerant/ lubricant mixture after being exposed to a pressure drop. The refrigerants being examined include baseline refrigerants: CFC-12 (R-12) and HCFC-22 (R-22); alternative refrigerants: HFC-32 (R-32), R-125, R-134a, and R-143a; and blended refrigerants: R-404A, R-407C, and R-410A. The baseline refrigerants are tested with ISO 32 (Witco 3GS) and ISO 68 (4GS) mineral oils while the alternative and blended refrigerants are tested with two ISO 68 polyolesters (Witco SL68 and ICI RL68H).

  3. Optical properties of a heated cornstarch mixture

    Science.gov (United States)

    Vazquez-Landaverde, Pedro A.; Morales Sánchez, Eduardo; Huerta-Ruelas, Jorge A.

    2007-03-01

    In this study, the objective was to evaluate optical properties of a corn starch-water mixture as descriptors of its behavior under processing conditions. A solution of corn starch in water was prepared and heated from 25 to 85°C in a temperature-controlled optical cell. For the measurement of optical properties, a polarized laser beam modulated through a photoelastic modulator and an analyzer, was used as optical probe. It was possible to measure transmitted light, along with optical rotation. Optical measurements showed changes related to temperature dependent phenomena such as starch granule swelling and gelatinization, in the ranges 25 to 60°C, 60 to 85°C. Above 80°C transmission values were higher, due to the solution clarification caused by corn starch gelatinization. Regarding optical rotation, it was difficult to obtain reliable measurements at low temperatures due to the high turbidity of the system. However, once gel was formed at higher temperatures, optical rotation and light transmission increased. This study demonstrated that optical techniques are suitable for the study of the behavior of water-starch mixtures under processing conditions such as heating, revealing a promising future for the monitoring of such phenomena in the production line to lower costs and improve product quality.

  4. Thermodynamics of organic mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)]. E-mail: jagl@termo.uva.es; Mozo, Ismael [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Fuente, Isaias Garcia de la [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)

    2006-02-01

    Binary mixtures containing pyridine (PY), or 2-methylpyridine (2MPY) or 3-methylpyridine (3MPY) or 4-methylpyridine (4MPY) and an organic solvent as benzene, toluene, alkane, or 1-alkanol are investigated in the framework of DISQUAC. The corresponding interaction parameters are reported. The model describes accurately a whole set of thermodynamic properties: vapor-liquid equilibria (VLE), liquid-liquid equilibria (LLE), solid-liquid equilibria (SLE), molar excess Gibbs energies (G{sup E}), molar excess enthalpies (H{sup E}), molar excess heat capacities at constant pressure (C{sub P}{sup E}) and the concentration-concentration structure factor (S{sub CC}(0)). It is remarkable that DISQUAC correctly predicts the W-shaped curve of the C{sub P}{sup E} of the pyridine + n-hexadecane system. The model can be applied successfully to mixtures with strong positive or negative deviations from the Raoult's law. DISQUAC improves the theoretical results from UNIFAC (Dortmund version). The replacement of pyridine by a methylpyridine leads to a weakening of the amine-amine interactions, ascribed to the steric effect caused by the methyl group attached to the aromatic ring. This explains that for a given solvent (alkane, 1-alkanol) H{sup E}(pyridine)>H{sup E}(methylpyridine)

  5. Misturas NR/SBR: influência da ordem de adição dos aditivos da mistura e do tipo de carga sobre propriedades mecânicas NR/SBR Mixtures: influence of the additives addition sequence and filler type on mechanical properties

    Directory of Open Access Journals (Sweden)

    Daniel de B. Coelho

    2011-01-01

    Full Text Available Neste trabalho foram preparadas misturas de borracha natural (NR e copolímero de estireno-butadieno (SBR na proporção 1:1 em massa. A sequência de adição dos aditivos e a influência de cargas, como negro de fumo e mica, foram avaliadas com relação a propriedades físico-mecânicas. As misturas, feitas em misturador aberto de rolos segundo a norma ASTM D 3182, foram realizadas de quatro modos diferentes para a incorporação dos aditivos. Os vulcanizados foram investigados com relação às propriedades reométricas, propriedades mecânicas de resistências à tração e ao rasgamento, dureza (shore A e pela densidade de ligações cruzadas, de acordo a respectiva norma ASTM. Os resultados mostram que melhores desempenhos são obtidos quando os aditivos são primeiramente incorporados à SBR. Também foi verificada a superioridade do negro de fumo no aumento da maioria das propriedades mecânicas dos elastômeros, seja na composição com apenas uma das borrachas, seja nas composições com as duas borrachas misturadas.In this work, mixtures of natural rubber (NR and styrene-butadiene copolymer (SBR were prepared in 1/1 ratio. The sequence with which the additives were incorporated and the influence of fillers, such as mica and carbon black, were evaluated regarding the physical-mechanical properties. The mixtures were prepared in a two-roll mill, according to ASTM D 3182, using four strategies for the incorporation of the additives. Rheometric and mechanical properties of tensile and tear strengths, elongation at break, hardness (Shore A and crosslink density of the vulcanizates were investigated, according to the corresponding ASTM standard. The results showed that the best mechanical performance was achieved when the additives were incorporated in the SBR matrix. Carbon black was more efficient in improving most mechanical properties of the rubber composites, either in the compounds with only one of the rubbers or in their blends.

  6. Unusual solvatochromic absorbance probe behaviour within mixtures of poly(ethylene glycol)-400 + ionic liquid, [bmim][Tf2N

    Science.gov (United States)

    Ali, Anwar; Ali, Maroof; Malik, Nisar Ahmad; Uzair, Sahar

    2014-03-01

    The potentially green solvents made up of ionic liquids (ILs) and poly(ethylene glycols) may have wide range of the applications in many chemical and biochemical fields. In the present work, solvatochromic absorbance probe behaviour is used to assess the physicochemical properties of the mixtures composed of PEG-400 + IL, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf2N]. Lowest energy intramolecular charge-transfer absorbance maxima of a betaine dye, i.e., ETN , indicates the dipolarity/polarizability and/or hydrogen-bond donating (HBD) acidity of the [bmim][Tf2N] + PEG-400 mixtures to be even higher than that of neat [bmim][Tf2N], the solution component with higher dipolarity/polarizability and/or HBD acidity. Dipolarity/polarizability (π∗) obtained separately from the electronic absorbance response of probe N,N-diethyl-4-nitroaniline, and the HBD acidity (α) of PEG-400 + [bmim][Tf2N] mixtures are also observed to be anomalously high. A comparative study of the PEG + IL mixtures has also been done with PEG-400 + molecular organic solvents (protic polar [methanol], aprotic polar [N,N-dimethylformamide], and non polar, [benzene]) mixtures, but these mixtures do not show this type of unusual behaviour. A four-parameter simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation is shown to satisfactorily predict the solvatochromic parameters within PEG-400 + different solvent mixtures.

  7. Investigation on the Combined Effect of Fibers and Cement on the Mechanical Performance of Foamed Bitumen Mixtures Containing 100% RAP

    Directory of Open Access Journals (Sweden)

    Ehsan Ashouri Taziani

    2016-01-01

    Full Text Available Concerns about virgin aggregate sources and increasing demands for construction materials of transport infrastructures as the key parameters in development are the most important reasons, which convinced pavement engineers to develop new methods in order to use higher amount of recycled asphalt pavement (RAP. One of the common methodologies to produce mixtures containing RAP is foamed bitumen mix (FBM. In addition, according to previous research studies, incorporating various types of fibers and hydraulic binders such as cement could significantly improve the mechanical performance of mixtures. The present research study evaluated FBM containing 100% RAP and two types of fiber and Portland cement. Dynamic modulus, unconfined dynamic creep compression, and indirect tensile strength were evaluated in the laboratory at optimum moisture content, which was investigated in this research. Both types of fiber and cement proved to enhance specific properties of mixtures.

  8. Adiabatic Coupling Constant of Nitrobenzene- n-Alkane Critical Mixtures. Evidence from Ultrasonic Spectra and Thermodynamic Data

    Science.gov (United States)

    Mirzaev, Sirojiddin Z.; Kaatze, Udo

    2016-09-01

    Ultrasonic spectra of mixtures of nitrobenzene with n-alkanes, from n-hexane to n-nonane, are analyzed. They feature up to two Debye-type relaxation terms with discrete relaxation times and, near the critical point, an additional relaxation term due to the fluctuations in the local concentration. The latter can be well represented by the dynamic scaling theory. Its amplitude parameter reveals the adiabatic coupling constant of the mixtures of critical composition. The dependence of this thermodynamic parameter upon the length of the n-alkanes corresponds to that of the slope in the pressure dependence of the critical temperature and is thus taken another confirmation of the dynamic scaling model. The change in the variation of the coupling constant and of several other mixture parameters with alkane length probably reflects a structural change in the nitrobenzene- n-alkane mixtures when the number of carbon atoms per alkane exceeds eight.

  9. A modeling approach for heat conduction and radiation diffusion in plasma-photon mixture in temperature nonequilibrium

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-09

    We present a simple approach for determining ion, electron, and radiation temperatures of heterogeneous plasma-photon mixtures, in which temperatures depend on both material type and morphology of the mixture. The solution technique is composed of solving ion, electron, and radiation energy equations for both mixed and pure phases of each material in zones containing random mixture and solving pure material energy equations in subdivided zones using interface reconstruction. Application of interface reconstruction is determined by the material configuration in the surrounding zones. In subdivided zones, subzonal inter-material energy exchanges are calculated by heat fluxes across the material interfaces. Inter-material energy exchange in zones with random mixtures is modeled using the length scale and contact surface area models. In those zones, inter-zonal heat flux in each material is determined using the volume fractions.

  10. Bayesian Inference of a Finite Mixture of Inverse Weibull Distributions with an Application to Doubly Censoring Data

    Directory of Open Access Journals (Sweden)

    Navid Feroze

    2016-03-01

    Full Text Available The families of mixture distributions have a wider range of applications in different fields such as fisheries, agriculture, botany, economics, medicine, psychology, electrophoresis, finance, communication theory, geology and zoology. They provide the necessary flexibility to model failure distributions of components with multiple failure modes. Mostly, the Bayesian procedure for the estimation of parameters of mixture model is described under the scheme of Type-I censoring. In particular, the Bayesian analysis for the mixture models under doubly censored samples has not been considered in the literature yet. The main objective of this paper is to develop the Bayes estimation of the inverse Weibull mixture distributions under doubly censoring. The posterior estimation has been conducted under the assumption of gamma and inverse levy using precautionary loss function and weighted squared error loss function. The comparisons among the different estimators have been made based on analysis of simulated and real life data sets.

  11. Joint effects of heavy metal binary mixtures on seed germination, root and shoot growth, bacterial bioluminescence, and gene mutation

    Institute of Scientific and Technical Information of China (English)

    In Chul Kong

    2013-01-01

    This investigation was to assess the joint effects of metal binary mixtures on seed germination,root and shoot growth,bacterial bioluminescence,and gene mutation based on the one toxic unit (1 TU) approach.Different sensitivities and orders of toxicity of metal mixtures were observed among the bioassays.In general,mostly additive or antagonistic effects were observed,while almost no synergistic effects by the binary metal mixtures in all bioassays.Therefore,the combined effects of heavy metals in the different bioassays were difficult to generalize since they were dependent on both chemical type and the organism used in each bioassay.However,these results indicate that a battery of bioassays with mixture chemicals as opposed to just a single assay with single metal is a better strategy for the bioassessment of environmental pollutants.

  12. Optimum Tolerance Design Using Component-Amount and Mixture-Amount Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.; Ozler, Cenk; Sehirlioglu, Ali Kemal

    2013-08-01

    One type of tolerance design problem involves optimizing component and assembly tolerances to minimize the total cost (sum of manufacturing cost and quality loss). Previous literature recommended using traditional response surface (RS) designs and models to solve this type of tolerance design problem. In this article, component-amount (CA) and mixture-amount (MA) approaches are proposed as more appropriate for solving this type of tolerance design problem. The advantages of the CA and MA approaches over the RS approach are discussed. Reasons for choosing between the CA and MA approaches are also discussed. The CA and MA approaches (experimental design, response modeling, and optimization) are illustrated using real examples.

  13. Generalized transport coefficients for inelastic Maxwell mixtures under shear flow

    Science.gov (United States)

    Garzó, Vicente; Trizac, Emmanuel

    2015-11-01

    The Boltzmann equation framework for inelastic Maxwell models is considered to determine the transport coefficients associated with the mass, momentum, and heat fluxes of a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. The Boltzmann equation is solved by means of a Chapman-Enskog-type expansion around the (local) shear flow distributions fr(0 ) for each species that retain all the hydrodynamic orders in the shear rate. Due to the anisotropy induced by the shear flow, tensorial quantities are required to describe the transport processes instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled equations, which can be analytically solved as functions of the shear rate a , the coefficients of restitution αr s, and the parameters of the mixture (masses, diameters, and composition). Since the reference distribution functions fr(0 ) apply for arbitrary values of the shear rate and are not restricted to weak dissipation, the corresponding generalized coefficients turn out to be nonlinear functions of both a and αr s. The dependence of the relevant elements of the three diffusion tensors on both the shear rate and dissipation is illustrated in the tracer limit case, the results showing that the deviation of the generalized transport coefficients from their forms for vanishing shear rates is in general significant. A comparison with the previous results obtained analytically for inelastic hard spheres by using Grad's moment method is carried out, showing a good agreement over a wide range of values for the coefficients of restitution. Finally, as an application of the theoretical expressions derived here for the transport coefficients, thermal diffusion segregation of an intruder immersed in a granular gas is also studied.

  14. Analytical processing of binary mixture information by olfactory bulb glomeruli.

    Directory of Open Access Journals (Sweden)

    Max L Fletcher

    Full Text Available Odors are rarely composed of a single compound, but rather contain a large and complex variety of chemical components. Often, these mixtures are perceived as having unique qualities that can be quite different than the combination of their components. In many cases, a majority of the components of a mixture cannot be individually identified. This synthetic processing of odor information suggests that individual component representations of the mixture must interact somewhere along the olfactory pathway. The anatomical nature of sensory neuron input into segregated glomeruli with the bulb suggests that initial input of odor information into the bulb is analytic. However, a large network of interneurons within the olfactory bulb could allow for mixture interactions via mechanisms such as lateral inhibition. Currently in mammals, it is unclear if postsynaptic mitral/tufted cell glomerular mixture responses reflect the analytical mixture input, or provide the initial basis for synthetic processing with the olfactory system. To address this, olfactory bulb glomerular binary mixture representations were compared to representations of each component using transgenic mice expressing the calcium indicator G-CaMP2 in olfactory bulb mitral/tufted cells. Overall, dorsal surface mixture representations showed little mixture interaction and often appeared as a simple combination of the component representations. Based on this, it is concluded that dorsal surface glomerular mixture representations remain largely analytical with nearly all component information preserved.

  15. Mixture Model and MDSDCA for Textual Data

    Science.gov (United States)

    Allouti, Faryel; Nadif, Mohamed; Hoai An, Le Thi; Otjacques, Benoît

    E-mailing has become an essential component of cooperation in business. Consequently, the large number of messages manually produced or automatically generated can rapidly cause information overflow for users. Many research projects have examined this issue but surprisingly few have tackled the problem of the files attached to e-mails that, in many cases, contain a substantial part of the semantics of the message. This paper considers this specific topic and focuses on the problem of clustering and visualization of attached files. Relying on the multinomial mixture model, we used the Classification EM algorithm (CEM) to cluster the set of files, and MDSDCA to visualize the obtained classes of documents. Like the Multidimensional Scaling method, the aim of the MDSDCA algorithm based on the Difference of Convex functions is to optimize the stress criterion. As MDSDCA is iterative, we propose an initialization approach to avoid starting with random values. Experiments are investigated using simulations and textual data.

  16. Bayesian Estimation of a Mixture Model

    Directory of Open Access Journals (Sweden)

    Ilhem Merah

    2015-05-01

    Full Text Available We present the properties of a bathtub curve reliability model having both a sufficient adaptability and a minimal number of parameters introduced by Idée and Pierrat (2010. This one is a mixture of a Gamma distribution G(2, (1/θ and a new distribution L(θ. We are interesting by Bayesian estimation of the parameters and survival function of this model with a squared-error loss function and non-informative prior using the approximations of Lindley (1980 and Tierney and Kadane (1986. Using a statistical sample of 60 failure data relative to a technical device, we illustrate the results derived. Based on a simulation study, comparisons are made between these two methods and the maximum likelihood method of this two parameters model.

  17. CRITICALITY CURVES FOR PLUTONIUM HYDRAULIC FLUID MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    WITTEKIND WD

    2007-10-03

    This Calculation Note performs and documents MCNP criticality calculations for plutonium (100% {sup 239}Pu) hydraulic fluid mixtures. Spherical geometry was used for these generalized criticality safety calculations and three geometries of neutron reflection are: {sm_bullet}bare, {sm_bullet}1 inch of hydraulic fluid, or {sm_bullet}12 inches of hydraulic fluid. This document shows the critical volume and critical mass for various concentrations of plutonium in hydraulic fluid. Between 1 and 2 gallons of hydraulic fluid were discovered in the bottom of HA-23S. This HA-23S hydraulic fluid was reported by engineering to be Fyrquel 220. The hydraulic fluid in GLovebox HA-23S is Fyrquel 220 which contains phosphorus. Critical spherical geometry in air is calculated with 0 in., 1 in., or 12 inches hydraulic fluid reflection.

  18. POROSITY CALCULATION OF MIXTURES OF FIBROUS PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Ruping Zou; Aibing Yu

    2003-01-01

    The initial forming of fiber blend to high green density, i.e. the packing of fibrous particles, is important to the reinforcement of composite materials. It is very useful to develop a general predictive method for the optimum selection of particle mixtures for the property control of ceramic or composite products. This paper presents such a mathematical model developed on the basis of the similarity analysis between the spherical and non-spherical particle packings and assesses its applicability to the packing of fibrous particles with discrete and/or continuous length distributions. The results indicate that the model can predict this packing system well and hence provide an effective way to solve various packing problems in the composite materials processing.

  19. Quantum-coherent mixtures of causal relations

    CERN Document Server

    MacLean, Jean-Philippe W; Spekkens, Robert W; Resch, Kevin J

    2016-01-01

    Understanding the causal influences that hold among the parts of a system is critical both to explaining that system's natural behaviour and to controlling it through targeted interventions. In a quantum world, understanding causal relations is equally important, but the set of possibilities is far richer. The two basic ways in which a pair of time-ordered quantum systems may be causally related are by a cause-effect mechanism or by a common cause acting on both. Here, we show that it is possible to have a coherent mixture of these two possibilities. We realize such a nonclassical causal relation in a quantum optics experiment and derive a set of criteria for witnessing the coherence based on a quantum version of Berkson's paradox. The interplay of causality and quantum theory lies at the heart of challenging foundational puzzles, such as Bell's theorem and the search for quantum gravity, but could also provide a resource for novel quantum technologies.

  20. Processes assessment in binary mixture plant

    Directory of Open Access Journals (Sweden)

    N. Shankar Ganesh, T. Srinivas

    2013-01-01

    Full Text Available Binary fluid system has an efficient system of heat recovery compared to a single fluid system due to a better temperature match between hot and cold fluids. There are many applications with binary fluid system i.e. Kalina power generation, vapor absorption refrigeration, combined power and cooling etc. Due to involvement of three properties (pressure, temperature and concentration in the processes evaluation, the solution is complicated compared to a pure substance. The current work simplifies this complex nature of solution and analyzes the basic processes to understand the processes behavior in power generation as well as cooling plants. Kalina power plant consists of regenerator, heat recovery vapor generator, condenser, mixture, separator, turbine, pump and throttling device. In addition to some of these components, the cooling plant consists of absorber which is similar in operation of condenser. The amount of vapor at the separator decreases with an increase in its pressure and temperature.

  1. Derived thermodynamic properties of alcohol + cyclohexylamine mixtures

    Directory of Open Access Journals (Sweden)

    IVONA R. RADOVIĆ

    2010-02-01

    Full Text Available Thermal expansion coefficients, α, excess thermal expansion coefficients, αE, isothermal coefficients of pressure excess molar enthalpy, (∂HE/∂pT,x, partial molar volumes, , partial molar volumes at infinite dilution, , partial excess molar volumes, , and partial excess molar volumes at infinite dilution, , were calculated using experimental densities and excess molar volumes, , data. All calculations are performed for the binary systems of cyclohexylamine with 1-propanol or 1-butanol or 2-butanol or 2-methyl-2-propanol. The Redlich–Kister polynomial and the reduced excess molar volume approach were used in the evaluation of these properties. In addition, the aim of this investigation was to provide a set of various volumetric data in order to asses the influence of temperature, chain length and position of hydroxyl group in the alcohol molecule on the molecular interactions in the examined binary mixtures.

  2. Thermodynamic modeling of CO2 mixtures

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel

    performed satisfactorily and predicted the general behavior of the systems, but qCPA used fewer adjustable parameters to achieve similar predictions. It has been demonstrated that qCPA is a promising model which, compared to CPA, systematically improves the predictions of the experimentally determined phase......, accurate predictions of the thermodynamic properties and phase equilibria of mixtures containing CO2 are challenging with classical models such as the Soave-Redlich-Kwong (SRK) equation of state (EoS). This is believed to be due to the fact, that CO2 has a large quadrupole moment which the classical models...... do not explicitly account for. In this thesis, in an attempt to obtain a physically more consistent model, the cubicplus association (CPA) EoS is extended to include quadrupolar interactions. The new quadrupolar CPA (qCPA) can be used with the experimental value of the quadrupolemoment...

  3. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  4. Quantum-coherent mixtures of causal relations

    Science.gov (United States)

    MacLean, Jean-Philippe W.; Ried, Katja; Spekkens, Robert W.; Resch, Kevin J.

    2017-01-01

    Understanding the causal influences that hold among parts of a system is critical both to explaining that system's natural behaviour and to controlling it through targeted interventions. In a quantum world, understanding causal relations is equally important, but the set of possibilities is far richer. The two basic ways in which a pair of time-ordered quantum systems may be causally related are by a cause-effect mechanism or by a common-cause acting on both. Here we show a coherent mixture of these two possibilities. We realize this nonclassical causal relation in a quantum optics experiment and derive a set of criteria for witnessing the coherence based on a quantum version of Berkson's effect, whereby two independent causes can become correlated on observation of their common effect. The interplay of causality and quantum theory lies at the heart of challenging foundational puzzles, including Bell's theorem and the search for quantum gravity. PMID:28485394

  5. Bioavailability and variability of biphasic insulin mixtures

    DEFF Research Database (Denmark)

    Søeborg, Tue; Rasmussen, Christian Hove; Mosekilde, Erik

    2012-01-01

    Absorption of subcutaneously administered insulin is associated with considerable variability. Some of this variability was quantitatively explained for both soluble insulin and insulin suspensions in a recent contribution to this journal (Søeborg et al., 2009). In the present article......, the absorption kinetics for mixtures of insulins is described. This requires that the bioavailability of the different insulins is considered. A short review of insulin bioavailability and a description of the subcutaneous depot thus precede the presentation of possible mechanisms associated with subcutaneous...... insulin degradation. Soluble insulins are assumed to be degraded enzymatically in the subcutaneous tissue. Suspended insulin crystals form condensed heaps that are assumed to be degraded from their surface by invading macrophages. It is demonstrated how the shape of the heaps affects the absorption...

  6. Theory of phase equilibria for model mixtures of n-alkanes, perfluoroalkanes and perfluoroalkylalkane diblock surfactants

    Science.gov (United States)

    Dos Ramos, María Carolina; Blas, Felipe J.

    2007-05-01

    An extension of the SAFT-VR equation of state, the so-called hetero-SAFT approach [Y. Peng, H. Zhao, and C. McCabe, Molec. Phys. 104, 571 (2006)], is used to examine the phase equilibria exhibited by a number of model binary mixtures of n-alkanes, perfluoroalkanes and perfluoroalkylalkane diblock surfactants. Despite the increasing recent interest in semifluorinated alkanes (or perfluoroalkylalkane diblock molecules), the phase behaviour of mixtures involving these molecules with n-alkanes or perfluoroalkanes is practically unknown from the experimental point of view. In this work, we use simple molecular models for n-alkanes, perfluoroalkanes and perfluoroalkylalkane diblock molecules to predict, from a molecular perspective, the phase behaviour of selected model mixtures of perfluoroalkylalkanes with n-alkanes and perfluoroalkanes. In particular, we focus our interest on the understanding of the microscopic conditions that control the liquid-liquid separation and the stabilization of these mixtures. n-Alkanes and perfluoroalkanes are modelled as tangentially bonded monomer segments with molecular parameters taken from the literature. The perfluoroalkylalkane diblock molecules are modelled as heterosegmented diblock chains, with parameters for the alkyl and perfluoroalkyl segments developed in earlier work. This simple approach, which was proposed in previous work [P. Morgado, H. Zhao, F. J. Blas, C. McCabe, L. P. N. Rebelo, and E. J. M. Filipe, J. Phys. Chem. B, 111, 2856], is now extended to describe model n-alkane (or perfluoroalkane) + perfluroalkylalkane binary mixtures. We have obtained the phase behaviour of different mixtures and studied the effect of the molecular weight of n-alkanes and perfluoroalkanes on the type of phase behaviour observed in these mixtures. We have also analysed the effect of the number of alkyl and perfluoroalkyl chemical groups in the surfactant molecule on the phase behaviour. In addition to the usual vapour-liquid phase

  7. Critical Phenomena in Liquid-Liquid Mixtures

    Science.gov (United States)

    Jacobs, D. T.

    2000-04-01

    Critical phenomena provide intriguing and essential insight into many issues in condensed matter physics because of the many length scales involved. Large density or concentration fluctuations near a system's critical point effectively mask the identity of the system and produce universal phenomena that have been well studied in simple liquid-vapor and liquid-liquid systems. Such systems have provided useful model systems to test theoretical predictions which can then be extended to more complicated systems. Along various thermodynamic paths, several quantities exhibit a simple power-law dependence close to the critical point. The critical exponents describing these relationships are universal and should depend only on a universality class determined by the order-parameter and spatial dimensionality of the system. Liquid gas, binary fluid mixtures, uniaxial ferromagnetism, polymer-solvent, and protein solutions all belong to the same (Ising model) universality class. The diversity of critical systems that can be described by universal relations indicates that experimental measurements on one system should yield the same information as on another. Our experimental investigations have tested existing theory and also extended universal behavior into new areas. By measuring the coexistence curve, heat capacity, thermal expansion and static light scattering (turbidity) in various liquid-liquid and polymer-solvent systems, we have determined critical exponents and amplitudes that have sometimes confirmed and other times challenged current theory. Recent experiments investigating the heat capacity and light scattering in a liquid-liquid mixture very close to the critical point will be discussed. This research is currently supported by The Petroleum Research Fund and by NASA grant NAG8-1433 with some student support from NSF-DMR 9619406.

  8. Comparison of solvent mixtures for pressurized solvent extraction of soil fatty acid biomarkers.

    Science.gov (United States)

    Jeannotte, Richard; Hamel, Chantal; Jabaji, Suha; Whalen, Joann K

    2008-10-19

    The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v/v/v), chloroform:methanol (1:2, v/v), hexane:2-propanol (3:2, v/v) and acetone. Soils were from agricultural fields and had a wide range of clay, organic matter and microbial biomass contents. Total lipid fatty acid methyl esters (TL-FAMEs) were the extractable soil lipids identified and quantified with gas chromatography and flame ionization detection. Concentrations of TL-FAMEs ranged from 57.3 to 542.2 nmole g(-1) soil (dry weight basis). The highest concentrations of TL-FAMEs were extracted with chloroform:methanol:buffer or chloroform:methanol mixtures than with the hexane:2-propanol or acetone solvents. The concentrations of TL-FAMEs in chemical groups, including saturated, branched, mono- and poly-unsaturated and hydroxy fatty acids were assessed, and biological groups (soil bacteria, mycorrhizal fungi, saprophytic fungi and higher plants) was distinguished. The extraction efficiency for the chemical and biological groups followed the general trend of: chloroform:methanol:buffer> or =chloroform:methanol>hexane:2-propanol=acetone. Discriminant analysis revealed differences in TL-FAME profiles based on the solvent mixture and the soil type. Although solvent mixtures containing chloroform and methanol were the most efficient for extracting lipids from the agricultural soils in this study, soil properties and the lipid groups to be studied should be considered when selecting a solvent mixture. According to our knowledge, this is the first report of soil lipid extraction with hexane:2-propanol or acetone in a pressurized solvent extraction system.

  9. Cooperativity in CYP2E1 metabolism of acetaminophen and styrene mixtures.

    Science.gov (United States)

    Hartman, Jessica H; Letzig, Lynda G; Roberts, Dean W; James, Laura P; Fifer, E Kim; Miller, Grover P

    2015-10-01

    Risk assessment for exposure to mixtures of drugs and pollutants relies heavily on in vitro characterization of their bioactivation and/or metabolism individually and extrapolation to mixtures assuming no interaction. Herein, we demonstrated that in vitro CYP2E1 metabolic activation of acetaminophen and styrene mixtures could not be explained through the Michaelis-Menten mechanism or any models relying on that premise. As a baseline for mixture studies with styrene, steady-state analysis of acetaminophen oxidation revealed a biphasic kinetic profile that was best described by negative cooperativity (Hill coefficient=0.72). The best-fit mechanism for this relationship involved two binding sites with differing affinities (Ks=830μM and Kss=32mM). Introduction of styrene inhibited that reaction less than predicted by simple competition and thus provided evidence for a cooperative mechanism within the mixture. Likewise, acetaminophen acted through a mixed-type inhibition mechanism to impact styrene epoxidation. In this case, acetaminophen competed with styrene for CYP2E1 (Ki=830μM and Ksi=180μM for catalytic and effector sites, respectively) and resulted in cooperative impacts on binding and catalysis. Based on modeling of in vivo clearance, cooperative interactions between acetaminophen and styrene resulted in profoundly increased styrene activation at low styrene exposure levels and therapeutic acetaminophen levels. Current Michaelis-Menten based toxicological models for mixtures such as styrene and acetaminophen would fail to detect this concentration-dependent relationship. Hence, future studies must assess the role of alternate CYP2E1 mechanisms in bioactivation of compounds to improve the accuracy of interpretations and predictions of toxicity.

  10. EFFECT OF INCREASING DOSES OF MUSHROOM SUBSTRATE ON THE ROOT MASS OF SELECTED LAWN MIXTURES

    Directory of Open Access Journals (Sweden)

    Beata Wiśniewska-Kadżajan

    2013-10-01

    Full Text Available To fertilize both grassland and turf lawns waste materials, including the substrate after mushroom cultivation have been used recently. The aim of this study was to determine the effect of the mushrooms substrate to change the amount of root mass of five turf lawns with varying precipitation of perennial ryegrass. Field experiment was established in 2004 in the agricultural station of University of Natural Science and Humanities in Siedlce. In the research, the following factors were used: 1 dose of mushroom substrate, 2 the mixtures lawns with different species composition and participation of perennial ryegrass. Within two years of research the evaluation of the amount of root mass of turf lawns were done. This assessment was made after plants’ vegetation in 2005 and 2006. The roots sampling of lawns were taken. After cleaning of the root and drying at 1050C, the mass was determined by weighing. The largest mass of roots (average from the study years and substrate doses was observed for the two-component mixture (M1 with 80% share of perennial ryegrass, and the smallest for five-component mixture (M5, where the share of perennial ryegrass was 40%. The average for research years of and mixtures type, indicates that most of the root mass formed the turf lawns with the largest mushroom substrate doses, but at least on the control object. The majority of the tested lawn mixtures, with the exception of mixture five (M5 produced a greater mass of roots in the second year (2006 than in the first (2005 year, despite worse weather conditions.

  11. Modeling of pharmaceuticals mixtures toxicity with deviation ratio and best-fit functions models.

    Science.gov (United States)

    Wieczerzak, Monika; Kudłak, Błażej; Yotova, Galina; Nedyalkova, Miroslava; Tsakovski, Stefan; Simeonov, Vasil; Namieśnik, Jacek

    2016-11-15

    The present study deals with assessment of ecotoxicological parameters of 9 drugs (diclofenac (sodium salt), oxytetracycline hydrochloride, fluoxetine hydrochloride, chloramphenicol, ketoprofen, progesterone, estrone, androstenedione and gemfibrozil), present in the environmental compartments at specific concentration levels, and their mutual combinations by couples against Microtox® and XenoScreen YES/YAS® bioassays. As the quantitative assessment of ecotoxicity of drug mixtures is an complex and sophisticated topic in the present study we have used two major approaches to gain specific information on the mutual impact of two separate drugs present in a mixture. The first approach is well documented in many toxicological studies and follows the procedure for assessing three types of models, namely concentration addition (CA), independent action (IA) and simple interaction (SI) by calculation of a model deviation ratio (MDR) for each one of the experiments carried out. The second approach used was based on the assumption that the mutual impact in each mixture of two drugs could be described by a best-fit model function with calculation of weight (regression coefficient or other model parameter) for each of the participants in the mixture or by correlation analysis. It was shown that the sign and the absolute value of the weight or the correlation coefficient could be a reliable measure for the impact of either drug A on drug B or, vice versa, of B on A. Results of studies justify the statement, that both of the approaches show similar assessment of the mode of mutual interaction of the drugs studied. It was found that most of the drug mixtures exhibit independent action and quite few of the mixtures show synergic or dependent action. Copyright © 2016. Published by Elsevier B.V.

  12. Nuclear fuel alloys or mixtures and method of making thereof

    Science.gov (United States)

    Mariani, Robert Dominick; Porter, Douglas Lloyd

    2016-04-05

    Nuclear fuel alloys or mixtures and methods of making nuclear fuel mixtures are provided. Pseudo-binary actinide-M fuel mixtures form alloys and exhibit: body-centered cubic solid phases at low temperatures; high solidus temperatures; and/or minimal or no reaction or inter-diffusion with steel and other cladding materials. Methods described herein through metallurgical and thermodynamics advancements guide the selection of amounts of fuel mixture components by use of phase diagrams. Weight percentages for components of a metallic additive to an actinide fuel are selected in a solid phase region of an isothermal phase diagram taken at a temperature below an upper temperature limit for the resulting fuel mixture in reactor use. Fuel mixtures include uranium-molybdenum-tungsten, uranium-molybdenum-tantalum, molybdenum-titanium-zirconium, and uranium-molybdenum-titanium systems.

  13. Maximum likelihood estimation of finite mixture model for economic data

    Science.gov (United States)

    Phoong, Seuk-Yen; Ismail, Mohd Tahir

    2014-06-01

    Finite mixture model is a mixture model with finite-dimension. This models are provides a natural representation of heterogeneity in a finite number of latent classes. In addition, finite mixture models also known as latent class models or unsupervised learning models. Recently, maximum likelihood estimation fitted finite mixture models has greatly drawn statistician's attention. The main reason is because maximum likelihood estimation is a powerful statistical method which provides consistent findings as the sample sizes increases to infinity. Thus, the application of maximum likelihood estimation is used to fit finite mixture model in the present paper in order to explore the relationship between nonlinear economic data. In this paper, a two-component normal mixture model is fitted by maximum likelihood estimation in order to investigate the relationship among stock market price and rubber price for sampled countries. Results described that there is a negative effect among rubber price and stock market price for Malaysia, Thailand, Philippines and Indonesia.

  14. Biosorption of binary mixtures of heavy metals by green macro alga, Caulerpa lentillifera

    Directory of Open Access Journals (Sweden)

    Prasert Pavasant

    2004-02-01

    Full Text Available Dried Caulerpa lentillifera was shown to have adsorption potential for Cu, Cd, Pb and Zn. The adsorption equilibrium was found to follow the Freundlich isotherm type. The adsorption of binary mixture of heavy metals solution onto the surface of the algae was found to be of competitive type where the adsorption capacity for any single metal decreased by 10-40% in the presence of the others. The total adsorption capacity of the algae was, in most cases, found to decrease by 30-50% when there was more than one heavy metal in the solution. However, the adsorption of mixtures of Cd and Cu, and of Pb and Cu did not show a reductionin the total adsorption capacity.

  15. Discrete velocity computations with stochastic variance reduction of the Boltzmann equation for gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Peter; Varghese, Philip; Goldstein, David [ASE-EM Department, UT Austin, 210 East 24th St, C0600, Austin, TX 78712 (United States)

    2014-12-09

    We extend a variance reduced discrete velocity method developed at UT Austin [1, 2] to gas mixtures with large mass ratios and flows with trace species. The mixture is stored as a collection of independent velocity distribution functions, each with a unique grid in velocity space. Different collision types (A-A, A-B, B-B, etc.) are treated independently, and the variance reduction scheme is formulated with different equilibrium functions for each separate collision type. The individual treatment of species enables increased focus on species important to the physics of the flow, even if the important species are present in trace amounts. The method is verified through comparisons to Direct Simulation Monte Carlo computations and the computational workload per time step is investigated for the variance reduced method.

  16. WEAR TESTS OF SLIDING SURFACES IN THE ENVIRONMENT OF MIXTURES OF LUBRICATING OILS AND REFRIGERANTS

    Directory of Open Access Journals (Sweden)

    Kasper Górny

    2014-03-01

    Full Text Available Elements of refrigeration compressors may be exposed to various types of wear processes, depending on the used oils and refrigerants. The presence of the refrigerant makes the lubricating properties and anti-oil mixture - factor much worse than in case of the lack of refrigerant oil. Current regulations on the use of ODS phase-out of working require refrigeration synthetic refrigerants HCFC (e.g. popular R22. The paper presents the effect of different mixtures of oils and refrigerants on friction coefficient and surface condition of cast iron and aluminium PA6. Tests were performed on a prototype machine using frictional node type block-on-ring, which is located inside a pressure chamber that simulates the refrigeration compressor. The results of the study confirm the possibility of using green refrigerant R290 (propane as a substitute for R22, while keeping the existing mineral oil.

  17. DURABILITY OF ASPHALT CONCRETE MIXTURES USING DOLOMITE AGGREGATES

    Directory of Open Access Journals (Sweden)

    Imad Al-Shalout

    2015-12-01

    Full Text Available This study deals with the durability of asphalt concrete, including the effects of different gradations, compaction temperatures and immersion time on the durability potential of mixtures. The specific objectives of this study are: to investigate the effect of compaction temperature on the mechanical properties of asphalt concrete mixtures; investigate the effect of bitumen content and different aggregate gradations on the durability potential of bituminous mixtures.

  18. Antiandrogenic activity of phthalate mixtures: Validity of concentration addition

    Energy Technology Data Exchange (ETDEWEB)

    Christen, Verena [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Crettaz, Pierre; Oberli-Schrämmli, Aurelia [Swiss Federal Office of Public Health, Division Chemical Products, 3003 Bern (Switzerland); Fent, Karl, E-mail: karl.fent@bluewin.ch [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology Zürich (ETH Zürich), Department of Environmental Sciences, 8092 Zürich (Switzerland)

    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 approach (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.

  19. Determination of thermal conductivity in foundry mould mixtures

    Directory of Open Access Journals (Sweden)

    G. Solenički

    2010-01-01

    Full Text Available For a thorough understanding of the behaviour of foundry mould mixtures, a good knowledge of thermal properties of mould materials is needed. Laboratory determination of thermal conductivity of mould mixtures enables a better control over scabbing defects which are a major problem in green sand mould mixtures. A special instrument has been designed for that purpose and it is described in this work.

  20. Tails assumptions and posterior concentration rates for mixtures of Gaussians

    OpenAIRE

    Naulet, Zacharie; Rousseau, Judith

    2016-01-01

    Nowadays in density estimation, posterior rates of convergence for location and location-scale mixtures of Gaussians are only known under light-tail assumptions; with better rates achieved by location mixtures. It is conjectured, but not proved, that the situation should be reversed under heavy tails assumptions. The conjecture is based on the feeling that there is no need to achieve a good order of approximation in regions with few data (say, in the tails), favoring location-scale mixtures w...

  1. Constrained Fisher Scoring for a Mixture of Factor Analyzers

    Science.gov (United States)

    2016-09-01

    global appearance model across the entire sensor network. constrained maximum likelihood estimation, mixture of factor analyzers, Newton’s method...ARL-TR-7836• SEP 2016 US Army Research Laboratory Constrained Fisher Scoring for a Mixture of Factor Analyzers by Gene T Whipps, Emre Ertin, and...TR-7836• SEP 2016 US Army Research Laboratory Constrained Fisher Scoring for a Mixture of Factor Analyzers by Gene T Whipps Sensors and Electron

  2. Additive mixture effects of estrogenic chemicals in human cell-based assays can be influenced by inclusion of chemicals with differing effect profiles.

    Directory of Open Access Journals (Sweden)

    Richard Mark Evans

    Full Text Available A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX and cell proliferation (ESCREEN endpoints. Two mixture designs were used: 1 a 'balanced' design with components present in proportion to a common effect concentration (e.g. an EC(10 and 2 a 'non-balanced' design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential

  3. A Modified Linear-Mixing Method for Calculating Atmospheric Path Radiances of Aerosol Mixtures

    Science.gov (United States)

    Abdou, W. A.; Martonchik, J. V.; Kahn, R. A.; West, R. A.; Diner, D. J.

    1997-01-01

    The top-of-atmosphere (TOA) path radiance generated by an aerosol mixture can be synthesized by linearly adding the contributions of the individual aerosol components, weighted by their fractional optical depths. The method, known as linear mixing, is exact in the single-scattering limit. When multiple scattering is significant, the method reproduces the atmospheric path radiance of the mixture with less than 3% errors for weakly absorbing aerosols up to optical thickness of 0.5. However, when strongly absorbing aerosols are included in the mixture, the errors are much larger. This is due to neglecting the effect of multiple interactions between the aerosol components, especially when the values of the single-scattering albedos of these components are so different that the parameter e = the sum of f(sub i)[(bar)omega(sub i) - (bar)omega(sub mix)]/(bar)omega(sub i) is larger than approximately 0.1, where (bar)omega(sub i)and f(sub i) are the single-scattering albedo and the fractional abundance of the ith component, and (bar)omega(sub mix) is the effective single-scattering albedo of the Mixture. We describe an empirical, modified linear-mixing method which effectively accounts for the multiple interactions between aerosol components. The modified and standard methods are identical when epsilon = 0.0 and give similar results when epsilon is less than or equal to 0.05. For optical depths larger than approximately 0.5, or when epsilon is greater than 0.05, only the modified method can reproduce the radiances within 5% error for common aerosol types up to optical thickness of 2.0. Because this method facilitates efficient and accurate atmospheric path radiance calculations for mixtures of a wide variety of aerosol types, it will be used as part of the aerosol retrieval methodology for the Earth Observing System (EOS) multiangle imaging spectroradiometer (MISR), scheduled for launch into polar orbit in 1998.

  4. Ecotoxicological characterization of polyoxyethylene glycerol ester non-ionic surfactants and their mixtures with anionic and non-ionic surfactants.

    Science.gov (United States)

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Fernández-Serrano, Mercedes

    2017-03-03

    This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria (Vibrio fischeri), microalgae (Pseudokirchneriella subcapitata), and freshwater crustaceans (Daphnia magna). Relationships between toxicity and the structural parameters such as unit of ethylene oxide (EO) and hydrophilic-lipophilic balance (HLB) were evaluated. Critical micellar concentration (CMC) in the conditions of the toxicity test was also determined. It was found that the toxicity of the aqueous solutions of PGE decreased when the number of EO units in the molecule, HLB, and CMC increased. PGEs showed lower CMC in marine medium, and the toxicity to V. ficheri is lower when the CMC was higher. Given their non-polar nature, narcosis was expected to be the primary mode of toxic action of PGEs. For the mixture of surfactants, we observed that the mixtures with PGE that had the higher numbers of EO units were more toxic than the aqueous solutions of pure surfactants. Moreover, we found that concentration addition was the type of action more likely to occur for mixtures of PGE with lower numbers of EO units with non-ionic surfactants (alkylpolyglucoside and fatty alcohol ethoxylate), whereas for the mixture of PGE with lower EO units and anionic surfactant (ether carboxylic derivative), the most common response type was response addition. In case of mixtures involving amphoteric surfactants and PGEs with the higher numbers of EO units, no clear pattern with regard to the mixture toxicity response type could be observed.

  5. Mixtures of conditional Gaussian scale mixtures applied to multiscale image representations.

    Directory of Open Access Journals (Sweden)

    Lucas Theis

    Full Text Available We present a probabilistic model for natural images that is based on mixtures of Gaussian scale mixtures and a simple multiscale representation. We show that it is able to generate images with interesting higher-order correlations when trained on natural images or samples from an occlusion-based model. More importantly, our multiscale model allows for a principled evaluation. While it is easy to generate visually appealing images, we demonstrate that our model also yields the best performance reported to date when evaluated with respect to the cross-entropy rate, a measure tightly linked to the average log-likelihood. The ability to quantitatively evaluate our model differentiates it from other multiscale models, for which evaluation of these kinds of measures is usually intractable.

  6. Use of multiline cultivars and cultivar mixtures for disease management.

    Science.gov (United States)

    Mundt, C C

    2002-01-01

    The usefulness of mixtures (multiline cultivars and cultivar mixtures) for disease management has been well demonstrated for rusts and powdery mildews of small grain crops. Such mixtures are more useful under some epidemiological conditions than under others, and experimental methodology, especially problems of scale, may be crucial in evaluating the potential efficacy of mixtures on disease. There are now examples of mixtures providing both low and high degrees of disease control for a wide range of pathosystems, including crops with large plants, and pathogens that demonstrate low host specificity, or are splash dispersed, soilborne, or insect vectored. Though most analyses of pathogen evolution in mixtures consider static costs of virulence to be the main mechanism countering selection for pathogen complexity, many other potential mechanisms need to be investigated. Agronomic and marketing considerations must be carefully evaluated when implementing mixture approaches to crop management. Practical difficulties associated with mixtures have often been overestimated, however, and mixtures will likely play an increasingly important role as we develop more sustainable agricultural systems.

  7. UTILIZATION OF WASTE PLASTIC BOTTLES IN ASPHALT MIXTURE

    Directory of Open Access Journals (Sweden)

    TAHER BAGHAEE MOGHADDAM

    2013-06-01

    Full Text Available Nowadays, large amounts of waste materials are being produced in the world. One of the waste materials is plastic bottle. Generating disposable plastic bottles is becoming a major problem in many countries. Using waste plastic as a secondary material in construction projects would be a solution to overcome the crisis of producing large amount of waste plastics in one hand and improving the structure’s characteristics such as resistance against cracking on the other hand. This study aimed to investigate the effects of adding plastic bottles in road pavement. Marshall properties as well as specific gravity of asphalt mixture containing different percentages of plastic bottles were evaluated. Besides, Optimum Asphalt Content (OAC was calculated for each percentages of plastic bottles used in the mix. The stiffness and fatigue characteristics of mixture were assessed at OAC value. Results showed that the stability and flow values of asphalt mixture increased by adding waste crushed plastic bottle into the asphalt mixture. Further, it was shown that the bulk specific gravity and stiffness of mixtures increased by adding lower amount of plastic bottles; however, adding higher amounts of plastic resulted in lower specific gravity and mix stiffness. In addition, it was concluded that the mixtures containing waste plastic bottles have lower OAC values compared to the conventional mixture, and this may reduce the amount of asphalt binder can be used in road construction projects. Besides, the mixtures containing waste plastic showed significantly greater fatigue resistance than the conventional mixture.

  8. [Construction of Three-Dimensional Isobologram for Ternary Pollutant Mixtures].

    Science.gov (United States)

    2015-12-01

    Tongji University, Shanghai 200092, China) Isobolographic analysis was widely used in the interaction assessment of binary mixtures. However, how to construct a three-dimensional (3D) isobologram for the assessment of toxicity interaction within ternary mixtures is still not reported up to date. The main purpose of this paper is to develop a 3D isobologram where the relative concentrations of three components are acted as three coordinate axes in 3D space to examine the toxicity interaction within ternary mixtures. Taking six commonly used pesticides in China, including three herbicides (2, 4-D, desmetryne and simetryn) and three insecticides ( dimethoate, imidacloprid and propoxur) as the mixture components, the uniform design ray procedure (UD-Ray) was used to rationally design the concentration composition of various components in the ternary mixtures so that effectively and comprehensively reflected the variety of actual environmental concentrations. The luminescent inhibition toxicities of single pesticides and their ternary mixtures to Vibrio fischeri at various concentration levels were determined by the microplate toxicity analysis. Selecting concentration addition (CA) as the addition reference, 3D isobolograms were constructed to study the toxicity interactions of various ternary mixtures. The results showed that the 3D isobologram could clearly and directly exhibit the toxicity interactions of ternary mixtures, and extend the use of isobolographic analysis into the ternary mixtures.

  9. Calculation and Analysis of Mean Opacity of Gold Mixtures

    Institute of Scientific and Technical Information of China (English)

    YAN An-ying; JIANG Ming; CHENG Xin-lu; YANG Xiang-dong

    2007-01-01

    A screened hydrogenic model for l splitting (SHML) is used to calculate the Rosseland mean opacities of high-Z Au, Ta, Yb, Ho, Gd, Sm, Nd, Sn, Ag plasmas and mixtures of gold and these elements at high temperature (T=200-400eV) and dense (ρ=1g/cm3).From the calculated Rosseland mean opacities of the mixtures, Au-Nd seems to be a better choice than other mixtures.Simultaneously, the reason that the mean opacities of mixture of Au-Sn decrease slightly when T=400eV is analyzed.

  10. Swelling characteristics of immersed sand-bentonite mixtures

    Institute of Scientific and Technical Information of China (English)

    丰土根; 崔红斌; 孙德安; 杜冰

    2008-01-01

    A laboratory one-dimensional consolidation apparatus was employed to research the swelling stress and volume of the sand-bentonite mixture under immersed conditions. The stress-strain characteristics of mixtures under varied mixing ratios and loading statuses were analyzed. Based on the results of tests, the mechanism of mixture swelling and collapsing was further discussed. The results show that mixtures with low sand ratios are suitable as hydraulic barrier or containment barriers of general landfills, geological repository and other hydraulic infrastructure works.

  11. Physical Stability of Freeze-Dried Isomalt Diastereomer Mixtures

    DEFF Research Database (Denmark)

    Koskinen, Anna-Kaisa; Fraser-Miller, Sara J.; Bøtker, Johan P.

    2016-01-01

    of the diastereomer compositions showed signs of physical instability when stored in the highest relative humidity condition. The four different crystalline diastereomer mixtures showed specific identifiable solid state properties. Conclusions Isomalt was shown to be a suitable excipient for freeze-drying. Preferably...... a mixture of the diastereomers should be used, as the mixture containing only one of the isomers showed physical instability. A mixture containing a 1:1 ratio of the two diastereomers showed the best physical stability in the amorphous form....

  12. Opacity Calculations for Non-Local Thermodynamic Equilibrium Mixtures

    Institute of Scientific and Technical Information of China (English)

    吴泽清; 韩国兴; 逄锦桥

    2002-01-01

    Based on the average atom model, a non-local thermodynamic equilibrium (non-LTE) model is developed to calculate opacity for mixtures. This model could be applied to high-Z problems. The mean ionization degrees of SiO2 of the present calculation are slightly higher compared with another model for mixtures. As an example, the opacity of Au and Nd mixture is calculated. The results show concrete non-LTE effects and the increase in opacity of the mixture is shown clearly.

  13. On superfluidity of asymmetric mixture of fermions: How two wrongs make a right

    Science.gov (United States)

    Grigorenko, Ilya; Kezerashvili, Roman Ya.

    2016-10-01

    The existence and stability of the superfluid state in a mixture of two fermion species with different masses and chemical potentials is investigated with respect to the asymmetry between the species. It is found that the mass asymmetry between the two types of particles can be effectively compensated by the asymmetry in their chemical potentials, this way increasing the range of the parameters, which allow the superfluid state.

  14. Behaviour of asphalt rubber mixtures with different crumb rubber and asphalt binder sources

    OpenAIRE

    Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Pais, Jorge C.; Trichês, Glicério

    2006-01-01

    This study evaluates the performance in laboratory of gap graded mixture prepared with different crumb rubber types and different conventional grade asphalt binders. The asphalt rubbers were prepared via wet process (continuous blend) and their properties were measured through the current tests: (i) penetration;(ii) softening point: (iii) resilience; (iv) apparent viscosity using a Brookfield viscometer. The rheological properties for conventional asphalts were measured too, in order to evalu...

  15. Bedload transport of sand-gravel mixtures with antidunes: flume experiments

    OpenAIRE

    Núñez González, Francisco

    2012-01-01

    In this thesis, the interaction between flow and sediment in alluvial channels is studied from an empirical approach, for conditions close or pertaining to supercritical flow, and for four types of sediment: sand, gravel and two mixtures with sand and gravel in a relative proportion of 70-30 and 55-45, respectively. The objective is to obtain by means of laboratory experiments a data set with the characteristics of flow, sediment transport, bed configurations and sediment sorting patterns in ...

  16. Multiphase Binary Mixture Flows in Porous Media in a Wide Pressure and Temperature Range Including Critical Conditions

    Science.gov (United States)

    Afanasyev, A.

    2011-12-01

    Multiphase flows in porous media with a transition between sub- and supercritical thermodynamic conditions occur in many natural and technological processes (e.g. in deep regions of geothermal reservoirs where temperature reaches critical point of water or in gas-condensate fields where subject to critical conditions retrograde condensation occurs and even in underground carbon dioxide sequestration processes at high formation pressure). Simulation of these processes is complicated due to degeneration of conservation laws under critical conditions and requires non-classical mathematical models and methods. A new mathematical model is proposed for efficient simulation of binary mixture flows in a wide range of pressures and temperatures that includes critical conditions. The distinctive feature of the model lies in the methodology for mixture properties determination. Transport equations and Darcy law are solved together with calculation of the entropy maximum that is reached in thermodynamic equilibrium and determines mixture composition. To define and solve the problem only one function - mixture thermodynamic potential - is required. Such approach allows determination not only single-phase states and two-phase states of liquid-gas type as in classical models but also two-phase states of liquid-liquid type and three-phase states. The proposed mixture model was implemented in MUFITS (Multiphase Filtration Transport Simulator) code for hydrodynamic simulations. As opposed to classical approaches pressure, enthalpy and composition variables together with fully implicit method and cascade procedure are used. The code is capable of unstructured grids, heterogeneous porous media, relative permeability and capillary pressure dependence on temperature and pressure, multiphase diffusion, optional number of sink and sources, etc. There is an additional module for mixture properties specification. The starting point for the simulation is a cubic equation of state that is

  17. Moisture sensitivity examination of asphalt mixtures using thermodynamic, direct adhesion peel and compacted mixture mechanical tests

    OpenAIRE

    Zhang, Jizhe; AIREY, Gordon D; Grenfell, James; Apeagyei, Alex K.

    2016-01-01

    Moisture damage in asphalt mixtures is a complicated mode of pavement distress that results in the loss of stiffness and structural strength of the asphalt pavement layers. This paper evaluated the moisture sensitivity of different aggregate–bitumen combinations through three different approaches: surface energy, peel adhesion and the Saturation Ageing Tensile Stiffness (SATS) tests. In addition, the results obtained from these three tests were compared so as to characterise the relationship ...

  18. Incorporating Endmember Variability into Spectral Mixture Analysis Through Endmember Bundles

    Science.gov (United States)

    Bateson, C. Ann; Asner, Gregory P.; Wessman, Carol A.

    1998-01-01

    Variation in canopy structure and biochemistry induces a concomitant variation in the top-of-canopy spectral reflectance of a vegetation type. Hence, the use of a single endmember spectrum to track the fractional abundance of a given vegetation cover in a hyperspectral image may result in fractions with considerable error. One solution to the problem of endmember variability is to increase the number of endmembers used in a spectral mixture analysis of the image. For example, there could be several tree endmembers in the analysis because of differences in leaf area index (LAI) and multiple scatterings between leaves and stems. However, it is often difficult in terms of computer or human interaction time to select more than six or seven endmembers and any non-removable noise, as well as the number of uncorrelated bands in the image, limits the number of endmembers that can be discriminated. Moreover, as endmembers proliferate, their interpretation becomes increasingly difficult and often applications simply need the aerial fractions of a few land cover components which comprise most of the scene. In order to incorporate endmember variability into spectral mixture analysis, we propose representing a landscape component type not with one endmember spectrum but with a set or bundle of spectra, each of which is feasible as the spectrum of an instance of the component (e.g., in the case of a tree component, each spectrum could reasonably be the spectral reflectance of a tree canopy). These endmember bundles can be used with nonlinear optimization algorithms to find upper and lower bounds on endmember fractions. This approach to endmember variability naturally evolved from previous work in deriving endmembers from the data itself by fitting a triangle, tetrahedron or, more generally, a simplex to the data cloud reduced in dimension by a principal component analysis. Conceptually, endmember variability could make it difficult to find a simplex that both surrounds the data

  19. Electrostatic separator for micronized mixtures of metals and plastics originating from waste electric and electronic equipment

    Science.gov (United States)

    Messal, Sara; Corondan, Razvan; Chetan, Ionut; Ouiddir, Rabah; Medles, Karim; Dascalescu, Lucian

    2015-10-01

    In spite of their extensive use for processing mixtures of granules exceeding 1 mm in size, very few industrial electrostatic separators are capable of handling micronized metals and plastics originating from waste electric and electronic equipment. The aim of the present work is to validate the possibility of using a novel belt-type electrostatic separator for the selective sorting of such particulate mixtures, the dimensions of which are in the order of 0.1 mm. In this type of separator, the metal particles get charged by electrostatic induction in contact with the grounded metal belt electrode, while the plastics remain uncharged in the electric field and are collected separately. The experiments are performed with 2-g samples of a mixture composed in equal proportions (50% - 50%) of Aluminium and Acrylonitrile Butadiene Styrene (ABS) particles of average diameter ranging between 125 μm and 250 μm. They enabled the evaluation of the effects and the interaction of two control variables of the process: the angle of inclination of the roll-type electrode and the high voltage applied to it.

  20. Porous concrete mixtures for pervious urban pavements

    Directory of Open Access Journals (Sweden)

    Castro, J.

    2007-08-01

    Full Text Available The present study aimed to analyze the hydraulic and mechanical behaviour of a series of roller-compacted, laboratory porous concrete mixtures. The mix design variables examined were the actual void ratio in the hardened concrete and the water/cement ratio. From these results the better dosages from the mechanical and hydraulical behaviour point of view were determined. One of the designs developed was found to exhibit excellent hydraulic capacity and 20% greater strength than the mixtures recommended in the literature. Moreover, concrete with an actual void ratio of only 14% was observed to meet permeability requirements. Maximum flexural strength of concretes with different w/c ratios was achieved with a cement paste content of 250 l/m3. Relationships were found between the void ratio and both 28-day concrete permeability and flexural strength. Finally, the doses exhibiting the best mechanical and hydraulic performance were identified.El trabajo realizado en este estudio consistió en analizar el comportamiento de diferentes dosificaciones de mezclas de hormigón poroso, fabricadas en laboratorio y compactadas con rodillo pesado para simular las condiciones de terreno. Las variables consideradas para el diseño de las mezclas fueron el porcentaje real de huecos en el hormigón endurecido y la razón agua/cemento. A partir de estos resultados se determinaron las dosificaciones que presentan mejor comportamiento desde el punto de vista mecánico e hidráulico. Los resultados muestran que existe una dosificación de hormigón poroso, distinta a las encontradas actualmente en la literatura internacional, que permite obtener resistencias hasta 20% más altas, manteniendo todavía una excelente capacidad hidráulica. Se determinó que una permeabilidad suficiente se puede obtener con un porcentaje real de huecos de 14%, y que agregar pasta de cemento en una proporción de 250 l/m3 permite maximizar la resistencia a flexotracción de hormigones que

  1. Realistic environmental mixtures of micropollutants in surface, drinking, and recycled water: herbicides dominate the mixture toxicity toward algae.

    Science.gov (United States)

    Tang, Janet Y M; Escher, Beate I

    2014-06-01

    Mixture toxicity studies with herbicides have focused on a few priority components that are most likely to cause environmental impacts, and experimental mixtures were often designed as equipotent mixtures; however, real-world mixtures are made up of chemicals with different modes of toxic action at arbitrary concentration ratios. The toxicological significance of environmentally realistic mixtures has only been scarcely studied. Few studies have simultaneously compared the mixture effect of water samples with designed reference mixtures comprised of the ratios of analytically detected concentrations in toxicity tests. In the present study, the authors address the effect of herbicides and other chemicals on inhibition of photosynthesis and algal growth rate. The authors tested water samples including secondary treated wastewater effluent, recycled water, drinking water, and storm water in the combined algae assay. The detected chemicals were mixed in the concentration ratios detected, and the biological effects of the water samples were compared with the designed mixtures of individual detected chemicals to quantify the fraction of effect caused by unknown chemicals. The results showed that herbicides dominated the algal toxicity in these environmentally realistic mixtures, and the contribution by the non-herbicides was negligible. A 2-stage model, which used concentration addition within the groups of herbicides and non-herbicides followed by the model of independent action to predict the mixture effect of the two groups, could predict the experimental mixture toxicity effectively, but the concentration addition model for herbicides was robust and sufficient for complex mixtures. Therefore, the authors used the bioanalytical equivalency concept to derive effect-based trigger values for algal toxicity for monitoring water quality in recycled and surface water. All water samples tested would be compliant with the proposed trigger values associated with the

  2. Numerical modelling of continuous spin detonation in rich methane-oxygen mixture

    Science.gov (United States)

    Trotsyuk, A. V.

    2016-10-01

    A numerical simulation of a two-dimensional structure of the detonation wave (DW) in a rich (equivalence ratio φ=1.5) methane-air mixture at normal initial condition has been conducted. The computations have been performed in a wide range of channel heights. From the analysis of the flow structure and the number of primary transverse waves in the channel, the dominant size of the detonation cell for studied mixture has been determined to be 45÷50 cm. Based on the fundamental studies of multi-front (cellular) structure of the classical propagating DW in methane mixtures, numerical simulation of continuous spin detonation (CSD) of rich (φ=1.2) methane-oxygen mixture has been carried out in the cylindrical detonation chamber (DC) of the rocket-type engine. We studied the global flow structure in DC, and the detailed structure of the front of the rotating DW. Integral characteristics of the detonation process - the distribution of average values of static and total pressure along the length of the DC, and the value of specific impulse have been obtained. The geometric limit of stable existence of CSD has been determined.

  3. The role of sample height in the stacking diagram of colloidal mixtures under gravity

    Science.gov (United States)

    Geigenfeind, Thomas; de las Heras, Daniel

    2017-02-01

    Bulk phase separation is responsible for the occurrence of stacks of different layers in sedimentation of colloidal mixtures. A recently proposed theory (de las Heras and Schmidt 2013 Soft Matter 9 8636) establishes a unique connection between the bulk phase behaviour and sedimentation-diffusion-equilibrium. The theory constructs a stacking diagram of all possible sequences of stacks under gravity in the limit of very high (infinite) sample heights. Here, we study the stacking diagrams of colloidal mixtures at finite sample height, h. We demonstrate that h plays a vital role in sedimentation-diffusion-equilibrium of colloidal mixtures. The region of the stacking diagram occupied by a given sequence of stacks depends on h. Hence, two samples with different heights but identical colloidal concentrations can develop different stacking sequences. In addition, the stacking diagrams for different heights can be qualitatively different since some stacking sequences occur only in a given interval of sample heights. We use the theory to investigate the stacking diagrams of both model bulk systems and mixtures of patchy particles that differ either by the number or by the types of patches.

  4. Prediction of heat-induced polymerization of different globular food proteins in mixtures with wheat gluten.

    Science.gov (United States)

    Lambrecht, Marlies A; Rombouts, Ine; De Ketelaere, Bart; Delcour, Jan A

    2017-04-15

    Egg, soy or whey protein co-exists with wheat gluten in different food products. Different protein types impact each other during heat treatment. A positive co-protein effect occurs when heat-induced polymerization of a mixture of proteins is more intense than that of the isolated proteins. The intrinsic protein characteristics of globular proteins which enhance polymerization in mixtures with gluten are unknown. In this report, a model was developed to predict potential co-protein effects in mixtures of gluten and globular proteins during heating at 100°C. A negative co-protein effect with addition of lysozyme, no co-protein effect with soy glycinin or egg yolk and positive co-protein effects with bovine serum albumin, (S-)ovalbumin, egg white, whole egg, defatted egg yolk, wheat albumins and wheat globulins were detected. The level of accessible free sulfhydryl groups and the surface hydrophobicity of unfolded globular proteins were the main characteristics in determining the co-protein effects in gluten mixtures.

  5. A hybrid pareto mixture for conditional asymmetric fat-tailed distributions.

    Science.gov (United States)

    Carreau, Julie; Bengio, Yoshua

    2009-07-01

    In many cases, we observe some variables X that contain predictive information over a scalar variable of interest Y , with (X,Y) pairs observed in a training set. We can take advantage of this information to estimate the conditional density p(Y|X = x). In this paper, we propose a conditional mixture model with hybrid Pareto components to estimate p(Y|X = x). The hybrid Pareto is a Gaussian whose upper tail has been replaced by a generalized Pareto tail. A third parameter, in addition to the location and spread parameters of the Gaussian, controls the heaviness of the upper tail. Using the hybrid Pareto in a mixture model results in a nonparametric estimator that can adapt to multimodality, asymmetry, and heavy tails. A conditional density estimator is built by modeling the parameters of the mixture estimator as functions of X. We use a neural network to implement these functions. Such conditional density estimators have important applications in many domains such as finance and insurance. We show experimentally that this novel approach better models the conditional density in terms of likelihood, compared to competing algorithms: conditional mixture models with other types of components and a classical kernel-based nonparametric model.

  6. Solubility and cation exchange in phosphate rock and saturated clinoptilolite mixtures

    Science.gov (United States)

    Allen, E. R.; Hossner, L. R.; Ming, D. W.; Henninger, D. L.

    1993-01-01

    Mixtures of zeolite and phosphate rock (PR) have the potential to provide slow-release fertilization of plants in synthetic soils by dissolution and ion-exchange reactions. This study was conducted to examine solubility and cation-exchange relationships in mixtures of PR and NH4- and K-saturated clinoptilolite (Cp). Batch-equilibration experiments were designed to investigate the effect of PR source, the proportion of exchangeable K and NH4, and the Cp to PR ratio on solution N, P, K, and Ca concentrations. The dissolution and cation-exchange reactions that occurred after mixing NH4- and K-saturated Cp with PR increased the solubility of the PR and simultaneously released NH4 and K into solution. The more reactive North Carolina (NC) PR rendered higher solution concentrations of NH4 and K when mixed with Cp than did Tennessee (TN) PR. Solution P concentrations for the Cp-NC PR mixture and the Cp-TN PR mixture were similar. Solution concentrations of N, P, K, and Ca and the ratios of these nutrients in solution varied predictably with the type of PR, the Cp/PR ratio, and the proportions of exchangeable K and NH4 on the Cp. Our research indicated that slow-release fertilization using Cp/PR media may provide adequate levels of N, P, and K to support plant growth. Solution Ca concentrations were lower than optimum for plant growth.

  7. Ultrasonic Investigations of Molecular Interaction in Binary Mixtures of Cyclohexanone with Isomers of Butanol

    Directory of Open Access Journals (Sweden)

    Sk. Md Nayeem

    2014-01-01

    Full Text Available Ultrasonic speed, u, and density, ρ, have been measured in binary liquid mixtures of cyclohexanone with the isomers of butanol (n-butanol, sec-butanol, and tert-butanol at 308.15 K over the entire range of composition. Molar volume (Vm, adiabatic compressibility (ks, intermolecular free length (Lf, acoustic impedance (z, and their excess/deviation along with Δu have been calculated from the experimental data. These values have been fitted to Redlich-Kister type polynomial equation. Positive values of VmE, Δks, LfE and negative values of zE, Δu have been observed for all the liquid mixtures indicating the existence of weak interactions between components. Rupture of H-bond or reduction in H-bond strength of isomers of butanol or breaking of the structure of one or both of the components in a solution causes the existence of dispersions in the present investigated binary mixtures. The data obtained from V-m,1, V-m,2, and excess partial molar volumes V-m, 1E, V-m, 2E, reflects the inferences drawn from VmE. Furthermore, FTIR spectra support the conclusions drawn from excess/deviation properties. The measured values of ultrasonic speed for all the investigated mixtures have been compared with the theoretically estimated values using empirical relations such as, Nomoto, Van Dael and Vangeels, Impedance and Rao specific sound speed.

  8. Experimental wax mixtures for dental use.

    Science.gov (United States)

    Kotsiomiti, E; McCabe, J F

    1997-07-01

    Improvements in the properties of dental waxes were sought by alterations in their composition. Twenty-six blends of paraffin wax, beeswax and inorganic filler were subjected to the following tests: plastic deformation (flow), linear thermal expansion, elastic modulus and flexural strength. Flow tests were conducted in accordance with the corresponding ISO specification. Thermal expansion coefficients were estimated using thermomechanical analysis. Mechanical properties were tested using a universal testing machine. Pure paraffin and beeswax were used as controls. The results were subjected to analysis using correlation and regression. Regression coefficients in the range of 0.90-0.99 were obtained in most cases, flow tests exhibiting the highest coefficients and flexural strength the lowest. The incorporated filler particles reduced the flow of the natural waxes, especially of the ester-containing beeswax, and improved the elastic modulus and strength. Good correlation was found between the ingredient proportions and measured properties, suggesting a relationship between them, although this is quite complicated in the case of tertiary wax mixtures. The experimental blends exhibited properties that are potentially useful for a range of clinical applications.

  9. Mixture latent autoregressive models for longitudinal data

    CERN Document Server

    Bartolucci, Francesco; Pennoni, Fulvia

    2011-01-01

    Many relevant statistical and econometric models for the analysis of longitudinal data include a latent process to account for the unobserved heterogeneity between subjects in a dynamic fashion. Such a process may be continuous (typically an AR(1)) or discrete (typically a Markov chain). In this paper, we propose a model for longitudinal data which is based on a mixture of AR(1) processes with different means and correlation coefficients, but with equal variances. This model belongs to the class of models based on a continuous latent process, and then it has a natural interpretation in many contexts of application, but it is more flexible than other models in this class, reaching a goodness-of-fit similar to that of a discrete latent process model, with a reduced number of parameters. We show how to perform maximum likelihood estimation of the proposed model by the joint use of an Expectation-Maximisation algorithm and a Newton-Raphson algorithm, implemented by means of recursions developed in the hidden Mark...

  10. Structure of colloidal sphere-plate mixtures

    Science.gov (United States)

    Doshi, N.; Cinacchi, G.; van Duijneveldt, J. S.; Cosgrove, T.; Prescott, S. W.; Grillo, I.; Phipps, J.; Gittins, D. I.

    2011-05-01

    In addition to containing spherical pigment particles, coatings usually contain plate-like clay particles. It is thought that these improve the opacity of the paint film by providing an efficient spacing of the pigment particles. This observation is counterintuitive, as suspensions of particles of different shapes and sizes tend to phase separate on increase of concentration. In order to clarify this matter a model colloidal system is studied here, with a sphere-plate diameter ratio similar to that found in paints. For dilute suspensions, small angle neutron scattering revealed that the addition of plates leads to enhanced density fluctuations of the spheres, in agreement with new theoretical predictions. On increasing the total colloid concentration the plates and spheres phase separate due to the disparity in their shape. This is in agreement with previous theoretical and experimental work on colloidal sphere-plate mixtures, where one particle acts as a depleting agent. The fact that no large scale phase separation is observed in coatings is ascribed to dynamic arrest in intimately mixed, or possibly micro-phase separated structures, at elevated concentration.

  11. Mixture modeling approach to flow cytometry data.

    Science.gov (United States)

    Boedigheimer, Michael J; Ferbas, John

    2008-05-01

    Flow Cytometry has become a mainstay technique for measuring fluorescent and physical attributes of single cells in a suspended mixture. These data are reduced during analysis using a manual or semiautomated process of gating. Despite the need to gate data for traditional analyses, it is well recognized that analyst-to-analyst variability can impact the dataset. Moreover, cells of interest can be inadvertently excluded from the gate, and relationships between collected variables may go unappreciated because they were not included in the original analysis plan. A multivariate non-gating technique was developed and implemented that accomplished the same goal as traditional gating while eliminating many weaknesses. The procedure was validated against traditional gating for analysis of circulating B cells in normal donors (n = 20) and persons with Systemic Lupus Erythematosus (n = 42). The method recapitulated relationships in the dataset while providing for an automated and objective assessment of the data. Flow cytometry analyses are amenable to automated analytical techniques that are not predicated on discrete operator-generated gates. Such alternative approaches can remove subjectivity in data analysis, improve efficiency and may ultimately enable construction of large bioinformatics data systems for more sophisticated approaches to hypothesis testing.

  12. Solubility of C60 in solvent mixtures.

    Science.gov (United States)

    Kulkarni, Pradnya P; Jafvert, Chad T

    2008-02-01

    The potential large-scale production of fullerene C60 and its widespread use in consumer products may translate into occupational and public exposure and in long-term environmental exposure. To assess the risk and fate of C60 in the environment, it is important to understand its solvate formation in common industrial solvents as the solvates may affect various properties of C60 including reactivity and toxicity, particularly when solvates occur in C60 clusters. In this study, the solubility measurements in mixed solvent system can provide useful information about solvate formation. The solubility of C60 was measured in pure toluene, tetrahydrofuran, ethanol, and acetonitrile to be 3000, 11, 1.4, and 0.04 mg/L, respectively. Additionally, the solubility of C60 was measured in mixtures of toluene-acetonitrile, toluene-ethanol, toluene-tetrahydrofuran, and acetonitrile-tetrahydrofuran. The solubility data were modeled with some accuracy using Wohl's equation. The estimated crystal energy term for C60 in tetrahydrofuran was different than that in the other solvents, indicating that the C60 solid phase in equilibrium with tetrahydrofuran solution may be a solvated crystal.

  13. Multicomponent mixtures for cryoprotection and ligand solubilization

    Directory of Open Access Journals (Sweden)

    Lidia Ciccone

    2015-09-01

    Full Text Available Mixed cryoprotectants have been developed for the solubilization of ligands for crystallization of protein–ligand complexes and for crystal soaking. Low affinity lead compounds with poor solubility are problematic for structural studies. Complete ligand solubilization is required for co-crystallization and crystal soaking experiments to obtain interpretable electron density maps for the ligand. Mixed cryo-preserving compounds are needed prior to X-ray data collection to reduce radiation damage at synchrotron sources. Here we present dual-use mixes that act as cryoprotectants and also promote the aqueous solubility of hydrophobic ligands. Unlike glycerol that increases protein solubility and can cause crystal melting the mixed solutions of cryo-preserving compounds that include precipitants and solubilizers, allow for worry-free crystal preservation while simultaneously solubilizing relatively hydrophobic ligands, typical of ligands obtained in high-throughput screening. The effectiveness of these mixture has been confirmed on a human transthyretin crystals both during crystallization and in flash freezing of crystals.

  14. Structure of colloidal sphere-plate mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, N; Cinacchi, G; Van Duijneveldt, J S; Cosgrove, T; Prescott, S W [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Grillo, I [Institut Laue-Langevin, 6 rue Jules Horowitz BP 156, 38042 Grenoble Cedex 9 (France); Phipps, J [Imerys Minerals Ltd, Par Moor Centre, Par Moor Road, Par, Cornwall PL24 2SQ (United Kingdom); Gittins, D I, E-mail: Giorgio.Cinacchi@bristol.ac.uk, E-mail: J.S.van-Duijneveldt@bristol.ac.uk [Imerys Performance and Filtration Minerals Ltd, 130 Castilian Drive, Goleta, CA 93117 (United States)

    2011-05-18

    In addition to containing spherical pigment particles, coatings usually contain plate-like clay particles. It is thought that these improve the opacity of the paint film by providing an efficient spacing of the pigment particles. This observation is counterintuitive, as suspensions of particles of different shapes and sizes tend to phase separate on increase of concentration. In order to clarify this matter a model colloidal system is studied here, with a sphere-plate diameter ratio similar to that found in paints. For dilute suspensions, small angle neutron scattering revealed that the addition of plates leads to enhanced density fluctuations of the spheres, in agreement with new theoretical predictions. On increasing the total colloid concentration the plates and spheres phase separate due to the disparity in their shape. This is in agreement with previous theoretical and experimental work on colloidal sphere-plate mixtures, where one particle acts as a depleting agent. The fact that no large scale phase separation is observed in coatings is ascribed to dynamic arrest in intimately mixed, or possibly micro-phase separated structures, at elevated concentration.

  15. The Characteristics of Asphalt Concrete Binder Course (AC-BC Mixture with Bottom Ash as Aggregate Substitute

    Directory of Open Access Journals (Sweden)

    Sugiyanto G.

    2015-01-01

    Full Text Available Highways serve nearly 80-90% of the population mobility and flow of goods. Utilization of bottom ash, a waste from coal combustion, in highway construction is one of the alternatives to reduce environmental pollution and support Clean Development Mechanism Program of Kyoto Protocol. The aim of this study is to analyze the characteristics of AC-BC mixture that uses bottom ash as partial substitute of fine aggregate and comparing with a standard mixture. Laboratory tests are performed on two different types of mixtures. The tests show that optimum asphalt content for AC-BCStandard mixture is 5.20% while AC-BCBottom Ash mixture is 5.25%. Bottom ash has higher porosity along with a little break field and has round shape so that the asphalt absorption is bigger than the crushed stone. Bottom ash can be used as an alternative aggregate to increase the value of flow of the AC-BC mixture, thus converting waste to valuable material.

  16. DESIGNS FOR MIXTURE AND PROCESS VARIABLES APPLIED IN TABLET FORMULATIONS

    NARCIS (Netherlands)

    DUINEVELD, CAA; SMILDE, AK; DOORNBOS, DA

    1993-01-01

    Although there are several methods for the construction of a design for process variables and mixture variables, there are not very many methods which are suitable to combine mixture and process variables in one design. Some of the methods which are feasible will be shown. These methods will be

  17. Toxicological evaluation and risk assessment of chemical mixtures

    NARCIS (Netherlands)

    Cassee, F.R.; Groten, J.P.; Bladeren, P.J. van; Feron, V.J.

    1998-01-01

    A major objective of combination toxicology is to establish whether a mixture of chemicals will result in an effect similar to that expected on the basis of additivity. This requires understanding of the basic concepts of the combined toxicological action of the compounds of the mixture: simple

  18. Learning Mixtures of Polynomials of Conditional Densities from Data

    DEFF Research Database (Denmark)

    L. López-Cruz, Pedro; Nielsen, Thomas Dyhre; Bielza, Concha;

    2013-01-01

    Mixtures of polynomials (MoPs) are a non-parametric density estimation technique for hybrid Bayesian networks with continuous and discrete variables. We propose two methods for learning MoP ap- proximations of conditional densities from data. Both approaches are based on learning MoP approximations......- ods with the approach for learning mixtures of truncated basis functions from data....

  19. Rheological properties of asphalt mixtures containing various fibers

    Institute of Scientific and Technical Information of China (English)

    叶群山; 吴少鹏; 陈筝; 刘至飞

    2008-01-01

    Rheological characteristics of fiber-modified asphalt mixture were investigated.Cellulous fiber,polyester fiber and mineral fiber were used as additives for asphalt mixture,and the dosages were 0.3%,0.3%,0.4%,respectively.Dynamic modulus test using superpave simple performance tester(SPT) was adopted to study the dynamic modulus and phase angle for the control mixture and fiber-modified ones at various temperatures and frequencies.Test results show that the rheological properties can be improved significantly by the addition of various fibers.The dynamic modulus increases with the increase of frequency,and the phase angle decreases with the increase of frequency.When various fibers are used,the dynamic modulus increases and phase angle decreases at each frequency.This indicates that the stiffness and the elastic portion of fiber-modified asphalt mixtures can be enhanced when various fibers are used,which results in the change of viscoelastic properties of mixtures.The creep test results show that the total strain and the permanent strain of asphalt mixtures during load-unload cycle can be significantly reduced,which results in the improvement of resistance to permanent deformation for asphalt mixtures containing various fiber additives.The Burgers model can be employed effectively to illustrate the rheological properties of fiber modified asphalt mixtures.

  20. Predicting Development of an Epidemics on Cultivar Mixtures

    DEFF Research Database (Denmark)

    Østergård, Hanne

    1983-01-01

    A mathematical model for the development of an epidemic on a plant cultivar mixture illustrates the influence of the infection efficiency, spore production rate, proportion of deposited spores, frequency of autodeposition, and composition of the mixture on the genetic composition of the pathogen...

  1. Mixture including hydrogen and hydrocarbon having pressure-temperature stability

    Science.gov (United States)

    Mao, Wendy L. (Inventor); Mao, Ho-Kwang (Inventor)

    2009-01-01

    The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

  2. Kelvin Equation for a Non-Ideal Multicomponent Mixture

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1997-01-01

    The Kelvin equation is generalized by application to a case of a multicomponent non-ideal mixture. Such a generalization is necessary in order to describe the two-phase equilibrium in a capillary medium with respect to both normal and retrograde condensation. The equation obtained is applied...... to the equilibrium state of a hydrocarbon mixture ina gas-condensate reservoir....

  3. Directed Assembly of colloidal rods, spheres and their mixtures

    NARCIS (Netherlands)

    Bakker, H.E.

    2017-01-01

    The directed assembly of colloidal rods, spheres and their mixtures in external fields such as gravity, electric fields and shear flow was investigated. Using confocal microscopy we determined the experimental phase diagram of a binary mixture of colloidal silica rods and spheres that form a binary

  4. Evaluating Mixture Modeling for Clustering: Recommendations and Cautions

    Science.gov (United States)

    Steinley, Douglas; Brusco, Michael J.

    2011-01-01

    This article provides a large-scale investigation into several of the properties of mixture-model clustering techniques (also referred to as latent class cluster analysis, latent profile analysis, model-based clustering, probabilistic clustering, Bayesian classification, unsupervised learning, and finite mixture models; see Vermunt & Magdison,…

  5. Malabsorption of fructose-sorbitol mixtures. Interactions causing abdominal distress

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1987-01-01

    Hydrogen breath tests were performed on 10 healthy adults after they had ingested a mixture of sorbitol and fructose, in which these substances were present in amounts corresponding to the individual absorption capacities. A significant malabsorption of this mixture was evident in 7 of 10 subjects...

  6. Explaining slow convergence of EM in low noise linear mixtures

    OpenAIRE

    Petersen, Kaare Brandt; Winther, Ole

    2005-01-01

    This report conducts an investigation of the convergence properties of the EM algorithm used for linear mixture models. Since the linear mixture model is a rather general approach, the analysis is relevant for a wide range of models which to some degree are subsets of each other: Independent Component Analysis (ICA), probabilistic PCA, Factor Analysis (FA), Independent Factor Analysis (IFA) and Mean Field ICA.

  7. Mixture Experiment Alternatives to the Slack Variable Approach

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.; Landmesser, Samantha M.

    2009-07-01

    A mixture experiment involves mixing two or more components in various proportions and measuring one or more response variables on each mixture. This article presents mixture-experiment approaches for designing experiments and/or modeling the resulting data in situations where the slack-variable (SV) approach has been used. With the SV approach, one mixture component is designated the SV and the experiment is designed and/or the data are analyzed in terms of the remaining components. In a SV design, the proportion of the SV is obtained by subtracting from one the sum of the proportions of the remaining components, thus "taking up the slack". With the mixture-experiment approach, the experiment is designed and the data are analyzed using all of the mixture components. The article considers four situations in which the SV approach has been used, and explains for each situation that it is generally preferable to use an appropriate mixture-experiment approach. For each situation, the recommended mixture-experiment approach is discussed and compared to the SV approach using an example.

  8. Microscopic Hydrodynamic Modes in a Binary Hard Sphere Mixture

    Science.gov (United States)

    Reichl, L. E.; Gust, Erich D.

    2017-07-01

    We derive analytic microscopic expressions for the shear viscosity, the speed of sound, and the decay rates of the hydrodynamic modes in a hard sphere binary gas mixture directly from the spectral properties of coupled Boltzmann equations. We show that the analytic expressions give good agreement with experimental viscosity data and to the results of light scattering experiments on noble gas binary mixtures.

  9. DESIGNS FOR MIXTURE AND PROCESS VARIABLES APPLIED IN TABLET FORMULATIONS

    NARCIS (Netherlands)

    DUINEVELD, CAA; SMILDE, AK; DOORNBOS, DA

    1993-01-01

    Although there are several methods for the construction of a design for process variables and mixture variables, there are not very many methods which are suitable to combine mixture and process variables in one design. Some of the methods which are feasible will be shown. These methods will be comp

  10. Herbal mixtures in the traditional medicine of Eastern Cuba

    NARCIS (Netherlands)

    Hernández, J.; Volpato, G.

    2004-01-01

    Herbal mixtures in the traditional medicine of Eastern Cuba. Traditional herbal mixtures in Eastern Cuba are investigated through interviews with 130 knowledgeable people and traditional healers of the provinces of Santiago de Cuba and Guantanamo. One hundred seventy plant species and other products

  11. Coarsening Rates of Bicontinuous Structures in Polymer Mixtures

    NARCIS (Netherlands)

    Scholten, E.; Sagis, L.M.C.; Linden, van der E.

    2005-01-01

    We discuss the coarsening of domains in bicontinuous structure of aqueous polymer mixtures, driven by hydrodynamic flow. Taking into account the bending energy as a contribution to the interfacial energy, we derive a general expression for the coarsening rate in these mixtures. Examining the

  12. A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

    Science.gov (United States)

    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...

  13. Learning High-Dimensional Mixtures of Graphical Models

    CERN Document Server

    Anandkumar, A; Kakade, S M

    2012-01-01

    We consider the problem of learning mixtures of discrete graphical models in high dimensions and propose a novel method for estimating the mixture components with provable guarantees. The method proceeds mainly in three stages. In the first stage, it estimates the union of the Markov graphs of the mixture components (referred to as the union graph) via a series of rank tests. It then uses this estimated union graph to compute the mixture components via a spectral decomposition method. The spectral decomposition method was originally proposed for latent class models, and we adapt this method for learning the more general class of graphical model mixtures. In the end, the method produces tree approximations of the mixture components via the Chow-Liu algorithm. Our output is thus a tree-mixture model which serves as a good approximation to the underlying graphical model mixture. When the union graph has sparse node separators, we prove that our method has sample and computational complexities scaling as poly(p, ...

  14. Plasma Using a Simulated Gas Mixture: A Case Study on the Effect of Corona Electrodes

    Institute of Scientific and Technical Information of China (English)

    K. YOSHIDA; B. S. RAJANIKANTH; M. OKUBO

    2009-01-01

    In this study, reduction and desorption of oxides of nitrogen (NOx) were conducted using an electrical discharge plasma technique. The study was carried out using a simulated gas mixture to explore the possibility of re-generation of used adsorbents by a nonthermal plasma desorption technique. Three different types of corona electrodes, namely, pipe, helical wire, and straight wire, were used for analyzing their effectiveness in NOx reduction/desorption. The pipe-type corona electrode exhibited a nitric oxide (NO) conversion of 50%, which is 1.5 times that of the straight-wire-type electrode at an energy density of 175 J/L. The helical-wire-type corona electrode exhibited a NOx desorption efficiency almost 4 times that of the pipe-type electrode, indicating the possibility that corona-generated species play a crucial role in desorption.

  15. Viscoelastic Analysis of Asphalt Mixture Based on Creep Test

    Directory of Open Access Journals (Sweden)

    Lihua Zhao

    2013-01-01

    Full Text Available Two kinds of mineral fibers were added to AC-16C asphalt mixture. Trabecular bending creep experiments of asphalt mixtures were carried out at -10 and 20°C. The influence of mineral fibers on the low temperature viscoelasticity of asphalt mixtures were analyzed systemically. Furthermore, by using Origin, Burgers viscoelastic model was used to investigate the parameter regression for the creep test results at the different temperatures. The results show that the addition of mineral fibers can effectively improve the bending creep rate of asphalt mixtures, indicates the increase of crack resistance of asphalt mixtures. Good agreement between experimental data and Burgers model was found. The parameters of Burgers model at different temperatures can also provide data support for the viscoelastic design of asphalt pavements.

  16. Malabsorption of fructose-sorbitol mixtures. Interactions causing abdominal distress

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1987-01-01

    Hydrogen breath tests were performed on 10 healthy adults after they had ingested a mixture of sorbitol and fructose, in which these substances were present in amounts corresponding to the individual absorption capacities. A significant malabsorption of this mixture was evident in 7 of 10 subjects....... The mixture caused mild to severe gastrointestinal distress in five subjects. When the carbohydrates were given separately, symptoms were absent. There was a significant correlation between the individual absorption capacities of fructose and of sorbitol. A mixture containing a similar amount of fructose......, but given as sucrose, and a similar amount of sorbitol was further given to four of the seven subjects showing malabsorption of the fructose-sorbitol mixture. Malabsorption now failed to appear, and symptoms were absent. These findings are of potential importance for the understanding of the physiologic...

  17. Overlapping Mixtures of Gaussian Processes for the Data Association Problem

    CERN Document Server

    Lázaro-Gredilla, Miguel; Lawrence, Neil

    2011-01-01

    In this work we introduce a mixture of GPs to address the data association problem, i.e. to label a group of observations according to the sources that generated them. Unlike several previously proposed GP mixtures, the novel mixture has the distinct characteristic of using no gating function to determine the association of samples and mixture components. Instead, all the GPs in the mixture are global and samples are clustered following "trajectories" across input space. We use a non-standard variational Bayesian algorithm to efficiently recover sample labels and learn the hyperparameters. We show how multi-object tracking problems can be disambiguated and also explore the characteristics of the model in traditional regression settings.

  18. Thermodiffusion in multicomponent hydrocarbon mixtures: Experimental investigations and computational analysis

    Science.gov (United States)

    VanVaerenbergh, Stefan; Srinivasan, Seshasai; Saghir, M. Ziad

    2009-09-01

    In an unprecedented experimental investigation, a ternary and a four component hydrocarbon mixture at high pressure have been studied in a nearly convection free environment to understand the thermodiffusion process. A binary mixture has also been investigated in this environment. Experimental investigations of the three mixtures have been conducted in space onboard the spacecraft FOTON-M3 thereby isolating the gravity-induced convection that otherwise interferes with thermodiffusion experiments on Earth. The experimental results have also been used to test a thermodiffusion model that has been calibrated based on the results of previous experimental investigations. It was found that with an increase in the number of components in the mixtures, the performance of the thermodiffusion model deteriorated. Computational analysis was also made to estimate the possible sources of errors. Simulations showed that the vibrations of the spacecraft could influence the estimates of thermodiffusion factors. It was also found that they are sensitive to slight variations in the temperature of the mixture.

  19. Fitting of Finite Mixture Distributions to Motor Insurance Claims

    Directory of Open Access Journals (Sweden)

    P. Sattayatham

    2012-01-01

    Full Text Available Problem statement: The modeling of claims is an important task of actuaries. Our problem is in modelling the actual motor insurance claim data set. In this study, we show that the actual motor insurance claim can be fitted by a finite mixture model. Approach: Firstly, we analyse the actual data set and then we choose the finite mixture Lognormal distributions as our model. The estimated parameters of the model are obtained from the EM algorithm. Then, we use the K-S and A-D test for showing how well the finite mixture Lognormal distributions fit the actual data set. We also mention the bootstrap technique in estimating the parameters. Results: From the tests, we found that the finite mixture lognormal distributions fit the actual data set with significant level 0.10. Conclusion: The finite mixture Lognormal distributions can be fitted to motor insurance claims and this fitting is better when the number of components (k are increase.

  20. The scent of mixtures: rules of odour processing in ants.

    Science.gov (United States)

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

    2015-03-02

    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.