WorldWideScience

Sample records for hormone liquid phase

  1. Multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid with high-performance liquid chromatography for the determination of steroid sex hormones in water and urine.

    Science.gov (United States)

    Liao, Keren; Mei, Meng; Li, Haonan; Huang, Xiaojia; Wu, Cuiqin

    2016-02-01

    The development of a simple and sensitive analytical approach that combines multiple monolithic fiber solid-phase microextraction with liquid desorption followed by high-performance liquid chromatography with diode array detection is proposed for the determination of trace levels of seven steroid sex hormones (estriol, 17β-estradiol, testosterone, ethinylestradiol, estrone, progesterone and mestranol) in water and urine matrices. To extract the target analytes effectively, multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid was used to concentrate hormones. Several key extraction parameters including desorption solvent, extraction and desorption time, pH value and ionic strength in sample matrix were investigated in detail. Under the optimal experimental conditions, the limits of detection were found to be in the range of 0.027-0.12 μg/L. The linear range was 0.10-200 μg/L for 17β-estradiol, 0.25-200 μg/L estriol, ethinylestradiol and estrone, and 0.50-200 μg/L for the other hormones. Satisfactory linearities were achieved for analytes with the correlation coefficients above 0.99. Acceptable method reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations of both less than 8%. The enrichment factors ranged from 54- to 74-fold. Finally, the proposed method was successfully applied to the analysis of steroid sex hormones in environmental water samples and human urines with spiking recoveries ranged from 75.6 to 116%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Rapid and sensitive analysis of phthalate metabolites, bisphenol A, and endogenous steroid hormones in human urine by mixed-mode solid-phase extraction, dansylation, and ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Wang, He-xing; Wang, Bin; Zhou, Ying; Jiang, Qing-wu

    2013-05-01

    Steroid hormone levels in human urine are convenient and sensitive indicators for the impact of phthalates and/or bisphenol A (BPA) exposure on the human steroid hormone endocrine system. In this study, a rapid and sensitive method for determination of 14 phthalate metabolites, BPA, and ten endogenous steroid hormones in urine was developed and validated on the basis of ultra-performance liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry. The optimized mixed-mode solid phase-extraction separated the weakly acidic or neutral BPA and steroid hormones from acidic phthalate metabolites in urine: the former were determined in positive ion mode with a methanol/water mobile phase containing 10 mM ammonium formate; the latter were determined in negative ion mode with a acetonitrile/water mobile phase containing 0.1 % acetic acid, which significantly alleviated matrix effects for the analysis of BPA and steroid hormones. Dansylation of estrogens and BPA realized simultaneous and sensitive analysis of the endogenous steroid hormones and BPA in a single chromatographic run. The limits of detection were less than 0.84 ng/mL for phthalate metabolites and less than 0.22 ng/mL for endogenous steroid hormones and BPA. This proposed method had satisfactory precision and accuracy, and was successfully applied to the analyses of human urine samples. This method could be valuable when investigating the associations among endocrine-disrupting chemicals, endogenous steroid hormones, and relevant adverse outcomes in epidemiological studies.

  3. Modeling of liquid phases

    CERN Document Server

    Soustelle, Michel

    2015-01-01

    This book is part of a set of books which offers advanced students successive characterization tool phases, the study of all types of phase (liquid, gas and solid, pure or multi-component), process engineering, chemical and electrochemical equilibria, and the properties of surfaces and phases of small sizes. Macroscopic and microscopic models are in turn covered with a constant correlation between the two scales. Particular attention has been given to the rigor of mathematical developments. This second volume in the set is devoted to the study of liquid phases.

  4. Liquid Phase Equilibria for Habitability

    Science.gov (United States)

    Tan, S. P.

    2017-11-01

    The existence of liquid phase, which amplifies habitability, can be predicted using an equation of state from atmospheric composition, pressure, and temperature. If solid is also present, density inversion that keeps liquid from freezing is examined.

  5. Liquid Phase Sintering

    Science.gov (United States)

    2004-01-01

    Industry spends billions of dollars each year on machine tools to manufacture products out of metal. This includes tools for cutting every kind of metal part from engine blocks to Shuttle main engine components. Cutting tool tips often break because of weak spots or defects in their composition. Based on a new concept called defect trapping, space offers a novel environment to study defect formation in molten metal materials as they solidify. After the return of these materials from space, researchers can evaluate the source of the defect and seek ways to eliminate them in products prepared on Earth. A widely used process for cutting tip manufacturing is liquid phase sintering. Compared to Earth-sintered samples which slump due to buoyancy induced by gravity, space samples are uniformly shaped and defects remain where they are formed. By studying metals sintered in space the US tool industry can potentially enhance its worldwide competitiveness. The Consortium for Materials Development in Space along with Wyle Labs, Teledyne Advanced Materials, and McDornell Douglas have conducted experiments in space.

  6. Quantum Phase Liquids-Fermionic Superfluid without Phase Coherence

    OpenAIRE

    Wu, Ya-Jie; Zhou, Jiang; Kou, Su-Peng

    2014-01-01

    We investigate the two dimensional generalized attractive Hubbard model in a bipartite lattice, and and a "quantum phase liquid" phase, in which the fermions are paired but don't have phase coherence at zero temperature, in analogy to quantum spin liquid phase. Then, two types of topological quantum phase liquids with a small external magnetic field-Z2 quantum phase liquids and chiral quantum phase liquids-are discussed.

  7. On-line solid-phase extraction coupled to liquid chromatography tandem mass spectrometry optimized for the analysis of steroid hormones in urban wastewaters.

    Science.gov (United States)

    Fayad, Paul B; Prévost, Michèle; Sauvé, Sébastien

    2013-10-15

    An analytical method based on on-line SPE-LC-APCI-MS/MS has been developed for the detection and quantification of eight selected estrogenic and progestagenic steroid hormones; estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), levonorgestrel (LEVO), medroxyprogesterone (MEDRO), norethindrone (NORE) and progesterone (PROG) in wastewater matrices. The injection volume could range from 1 to 10-mL according to the expected concentration of steroid hormones in matrix. The method characteristics are: analysis time per sample (experiments for the on-line SPE method and chromatographic separation were performed in environmentally-relevant wastewater matrices. This method represents a compromise between analysis time, higher sample throughput capabilities, sample volume and simplicity for the analysis of both progestagenic and estrogenic steroid hormones in a single run, with LODs and LOQs sufficiently low to detect and quantify them in environmental wastewater matrices. Thus, the applicability of the method was tested on affluent and effluent wastewaters from two wastewater treatment facilities using different processes (biological and physico-chemical) to evaluate their removal efficiency for the detected steroid hormones. © 2013 Elsevier B.V. All rights reserved.

  8. Liquid-phase combinatorial synthesis.

    OpenAIRE

    Han, H; Wolfe, M M; Brenner, S; Janda, K D

    1995-01-01

    A concept termed liquid-phase combinatorial synthesis (LPCS) is described. The central feature of this methodology is that it combines the advantages that classic organic synthesis in solution offers with those that solid-phase synthesis can provide, through the application of a linear homogeneous polymer. To validate this concept two libraries were prepared, one of peptide and the second of nonpeptide origin. The peptide-based library was synthesized by a recursive deconvolution strategy [Er...

  9. Liquid phase chromatography on microchips

    DEFF Research Database (Denmark)

    Kutter, Jörg Peter

    2012-01-01

    explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...

  10. Synthesis in the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    1943-03-11

    Justification is presented for an I.G. Farben patent on synthesis of hydrocarbons from carbon monoxide and hydrogen in the liquid phase. Tracing the history of the process, the report notes that Pier worked out the basic patent in 1928. Duftschmid of Farben/Oppau subsequently worked out a variation of the process using for the fluid medium a synthesis product consisting mainly of products vaporizing in the reaction. The process used fixed-bed catalysts. Ruhrchemie A.G. objected to this patent on grounds that the process was already known. Meanwhile, Michael of Farben/Ludwigshafen devised another variation using mainly a finely distributed sintered catalyst and very fast stirring. The process required a high boiling, practically non-volatile liquid phase to keep the finely distributed catalyst in motion in the liquid during the reaction. A good distribution of carbon monoxide, hydrogen, and catalyst was obtained by having the gases enter either through a filter plate or by a rapid stirring of the liquid. The report concludes that since Michael's process was not for fixed catalysts, it was in no way dependent on the Duftschmid process or on Oppau's patent rights. A detailed chronology of work on the processes is included.

  11. APPARATUS FOR LIQUID PHASE EXTRACTION

    Science.gov (United States)

    Hicks, T.R.; Lehman, H.R.; Rubin, B.

    1958-09-16

    operation is described. It comprises a tubular colunm having upper and lower enlarged terminal portions, and a constricted central section containing fluid dispersal packing. Pulsing means are coupled to the upper portion of the column. The inlet for the less dense phase is located above the inlet for the denser phase and both are positioned so that liquids enter the constricted packingfilled central section. The apparatos also includes an interfacing level control, and means fer sensing the level of the interface actuate apparatus for controlling the rate of flow of input or discharge. The outlet for the less dense phase is located in the upper packing free portion of the colunm and that of the denser phase in the lower portion.

  12. Theory of the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Rank, V.

    1944-01-31

    This report discussed the regularities in the behavior of the liquid phase and illustrated these with a few examples and also discussed a method of testing of hydrogenation behavior of coals. A table was given that contained examples of the behavior of different coals in the liquid phase for the purpose of production of oils of different composition. All tests had been run at 600 atm with iron catalysts, a normal gas throughput, and with about a 50% paste. The remaining independent variables were the temperature, the throughput, and the composition of the pasting oils. When these three requirements were fixed, the conversion of a given coal, yield, composition of the oils produced, gasification, and asphalt production would be definite for a fixed method of working up the residue. Results would vary from coal to coal. As a general rule, the Ruhr coal seemed better suited to gasoline and middle oil production than the Upper Silesian coal. The recycling of oils in a closed cycle was not necessarily the best means to determine the particular method best suited to a given coal because of the possibility of superimposed effects that could obscure the issue. The use of B-bombs with a standard pasting oil was basically more correct in spite of the disadvantages of using a non-continuous process. 2 tables.

  13. Recent development of ionic liquid stationary phases for liquid chromatography.

    Science.gov (United States)

    Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

    2015-11-13

    Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Does C60 have a liquid phase?

    NARCIS (Netherlands)

    Hagen, M.H.J.; Meijer, E.J.; Mooij, G.C.A.M.; Frenkel, D.

    1993-01-01

    Above a substance's liquid–vapour critical point (i>Tc), the distinction between the liquid and vapour phases disappears. Below the triple point (T t), meanwhile (at which solid, liquid and vapour coexist), only the solid and vapour are stable. The liquid range, T c/T t, depends on the nature of the

  15. Supported ionic liquid-phase (SILP) catalysis

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Wasserscheid, P.

    2005-01-01

    The concept of supported ionic liquid-phase (SILP) catalysis has been demonstrated for gas- and liquid-phase continuous fixed-bed reactions using rhodium phosphine catalyzed hydroformylation of propene and 1-octene as examples. The nature of the support had important influence on both the catalytic...

  16. Operation with three liquid phases in a staged liquid-liquid contactor

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, R.A.; Ziegler, A.A.; Wigeland, R.A.; Bane, R.W.; Steindler, M.J.

    1983-03-01

    Operation with three liquid phases was demonstrated in a staged liquid-liquid contactor. The possibility that three liquid phases could be handled in a liquid-liquid contactor normally used with two liquid phases was initially established using a laboratory batch test. Tht three liquid phases were obtained using a thorium flow sheet having high concentrations of both acid and thorium. To analyze the batch test, the concept of a dimensionless dispersion number for use with two liquid phases was extended so that it could be applied to three liquid phases. Based on the batch tests, continuous flow tests were run in a staged liquid-liquid contactor used for solvent extraction. A critical factor in the success of these tests was determining the position of the liquid-liquid interface in the contactor. Thus, a contactor was used which allows the position of the liquid-liquid interface to be adjusted. Actual three-phase operation was demonstrated using a 4-cm annular centrifugal contactor, albeit with a somewhat greater (3 to 4 vol. %) aqueous-phase contamination of the organic exit stream than normal (< 1 vol. %).

  17. CATION-EXCHANGE SOLID-PHASE AND LIQUID-LIQUID ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    indicating a purer extract. KEY WORDS: Khat alkaloids, Solid phase extraction, Liquid-liquid extraction, HPLC, Genevac. INTRODUCTION. Khat (Catha edulis Vahl. Endl.) is an evergreen shrub or tree belonging to the Celastraceae family. Although the plant originates from Ethiopia, it occurs in Kenya, Malawi, Uganda,.

  18. Chiral liquid phase of simple quantum magnets

    Science.gov (United States)

    Wang, Zhentao; Feiguin, Adrian E.; Zhu, Wei; Starykh, Oleg A.; Chubukov, Andrey V.; Batista, Cristian D.

    2017-11-01

    We study a T =0 quantum phase transition between a quantum paramagnetic state and a magnetically ordered state for a spin S =1 XXZ Heisenberg antiferromagnet on a two-dimensional triangular lattice. The transition is induced by an easy-plane single-ion anisotropy D . At the mean-field level, the system undergoes a direct transition at a critical D =Dc between a paramagnetic state at D >Dc and an ordered state with broken U(1 ) symmetry at D field the phase diagram is very different and includes an intermediate, partially ordered chiral liquid phase. Specifically, we find that inside the paramagnetic phase the Ising (Jz) component of the Heisenberg exchange binds magnons into a two-particle bound state with zero total momentum and spin. This bound state condenses at D >Dc , before single-particle excitations become unstable, and gives rise to a chiral liquid phase, which spontaneously breaks spatial inversion symmetry, but leaves the spin-rotational U(1 ) and time-reversal symmetries intact. This chiral liquid phase is characterized by a finite vector chirality without long-range dipolar magnetic order. In our analytical treatment, the chiral phase appears for arbitrarily small Jz because the magnon-magnon attraction becomes singular near the single-magnon condensation transition. This phase exists in a finite range of D and transforms into the magnetically ordered state at some D calculations.

  19. Lyotropic Liquid Crystal Phases from Anisotropic Nanomaterials

    Directory of Open Access Journals (Sweden)

    Ingo Dierking

    2017-10-01

    Full Text Available Liquid crystals are an integral part of a mature display technology, also establishing themselves in other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors, just to name a few of the non-display applications. In recent years, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i addition of nanomaterials can change and thus tune the properties of the liquid crystal; (ii novel functionalities can be added to the liquid crystal; and (iii the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research effort has been concentrated on thermotropic systems, which change order as a function of temperature. Here we review the other side of the medal, the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids. Several classes of materials will be discussed, inorganic and mineral liquid crystals, viruses, nanotubes and nanorods, as well as graphene oxide.

  20. Effect of smoking on acute phase reactants, stress hormone ...

    African Journals Online (AJOL)

    However, the mechanisms which underpin these harmful inflammatory responses, have not been well documented. Objectives: The current study was undertaken to determine possible associations between systemic biomarkers of inflammation (acute phase reactants, stress hormones, leukocyte vitamin C) and smoking ...

  1. Smectic phases in ionic liquid crystals.

    Science.gov (United States)

    Bartsch, Hendrik; Bier, Markus; Dietrich, S

    2017-11-22

    Ionic liquid crystals (ILCs) are anisotropic mesogenic molecules which carry charges and therefore combine properties of liquid crystals, e.g. the formation of mesophases, and of ionic liquids, such as low melting temperatures and tiny triple-point pressures. Previous density functional calculations have revealed that the phase behavior of ILCs is strongly affected by their molecular properties, i.e. their aspect ratio, the loci of the charges, and their interaction strengths. Here, we report new findings concerning the phase behavior of ILCs as obtained by density functional theory and Monte Carlo simulations. The most important result is the occurrence of a novel, wide smectic-A phase [Formula: see text], at low temperature, the layer spacing of which is larger than that of the ordinary high-temperature smectic-A phase [Formula: see text]. Unlike the ordinary smectic S A phase, the structure of the [Formula: see text] phase consists of alternating layers of particles oriented parallel to the layer normal and oriented perpendicular to it.

  2. Maximum preheating in the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    1944-03-31

    This report dealt with the formation of hydrocarbons from CO or CO/sub 2/ to solve the problem of maximum preheating. Kroenig's old idea of operations with CO in the hydrogen was being tested to achieve increased temperatures in the converters. Dr. Kroenig tried to reduce the hydrogen consumption in the liquid phase when operating with oxygen-rich coals by the addition of a few percent CO to the fresh gas. This CO was supposed to compete with hydrogen for the oxygen of the coal, becoming converted to CO/sub 2/, which was stable at the relatively low temperatures of the converters. These experiments were discontinued. However, the idea of using the heat of reaction of the reaction of oxygen products with hydrogen to raise the temperature of the heater in the liquid phase was considered. It was known that the presence of even a few percent of CO in the fresh gas raised the converter temperature in the vapor phase dangerously, while the increase in the temperature of the preheater and the liquid phase converters amounted to but a few tenths of a millivolt. The reduction of CO with hydrogen was relatively slow but could be affected by catalysts. The heats of reactions for the various systems which could be utilized for heating were given. It was determined that from a standpoint of heat technology the formation of hydrocarbons from CO or CO/sub 2/ could be adapted to solve the problem of maximum preheating.

  3. Continuation of growth hormone therapy versus placebo in transition-phase patients with growth hormone deficiency

    DEFF Research Database (Denmark)

    Jørgensen, Jens; Nørrelund, Helene; Vahl, Nina

    2002-01-01

    In a placebo-controlled, parallel study of 18 patients with a mean age of 20 years who had confirmed growth hormone (GH) deficiency, we evaluated body composition, insulin sensitivity, and glucose turnover at baseline (when all were receiving GH replacement); after 12 months of continued GH therapy...... or placebo; and after a 12-month open phase of GH therapy. In the placebo group, insulin sensitivity and fat mass increased and lipid oxidation decreased, whereas glucose oxidation increased (p...

  4. Crystal-liquid-gas phase transitions and thermodynamic similarity

    CERN Document Server

    Skripov, Vladimir P; Schmelzer, Jurn W P

    2006-01-01

    Professor Skripov obtained worldwide recognition with his monograph ""Metastable liquids"", published in English by Wiley & Sons. Based upon this work and another monograph published only in Russia, this book investigates the behavior of melting line and the properties of the coexisting crystal and liquid phase of simple substances across a wide range of pressures, including metastable states of the coexisting phases. The authors derive new relations for the thermodynamic similarity for liquid-vapour phase transition, as well as describing solid-liquid, liquid-vapor and liquid-liquid phase tra

  5. Phase Segregation at the Liquid-Air Interface Prior to Liquid-Liquid Equilibrium.

    Science.gov (United States)

    Bermúdez-Salguero, Carolina; Gracia-Fadrique, Jesús

    2015-08-13

    Binary systems with partial miscibility segregate into two liquid phases when their overall composition lies within the interval defined by the saturation points; out of this interval, there is one single phase, either solvent-rich or solute-rich. In most systems, in the one-phase regions, surface tension decreases with increasing solute concentration due to solute adsorption at the liquid-air interface. Therefore, the solute concentration at the surface is higher than in the bulk, leading to the hypothesis that phase segregation starts at the liquid-air interface with the formation of two surface phases, before the liquid-liquid equilibrium. This phenomenon is called surface segregation and is a step toward understanding liquid segregation at a molecular level and detailing the constitution of fluid interfaces. Surface segregation of aqueous binary systems of alkyl acetates with partial miscibility was theoretically demonstrated by means of a thermodynamic stability test based on energy minimization. Experimentally, the coexistence of two surface regions was verified through Brewster's angle microscopy. The observations were further interpreted with the aid of molecular dynamics simulations, which show the diffusion of the acetates from the bulk toward the liquid-air interface, where acetates aggregate into acetate-rich domains.

  6. Temperature independent low voltage polymer stabilized blue phase liquid crystals

    Science.gov (United States)

    Kemiklioglu, E.; Hwang, J. Y.; Chien, L.-C.

    2012-03-01

    Blue phases are types of liquid crystal phase which can appear in a narrow temperature range between a chiral nematic phase and isotropic liquid phase. Blue Phase (BP) liquid crystals have been known to exist in a small temperature range. Recently, broadening the temperature range of a BP liquid crystal has occurred by using a mixture of nematic bimesogenic liquid crystals or by polymerizing a small amount of monomer in a BP to stabilize the cubic lattice against temperature variation. In this study, we report a low switching voltage polymer stabilized blue phase (PSBP) liquid crystal device. We showed the stabilization of blue phases over a temperature range of 30.4 °C including room temperature. We observed the temperature independent of Bragg wavelength. Furthermore, the polymer effect on the electo-optic properties of a self assembled nanostructured blue phase liquid crystal composites have been investigated. As well as the ratio between two monomers, the overall monomers concentration is controlled.

  7. Laser-induced metastable phases in liquids

    Science.gov (United States)

    Nath, Arpita; Sharma, Pooja; Khare, Alika

    2018-02-01

    Pulsed laser ablation at solid–liquid interfaces is gaining wide acceptance due to the production of functional nanomaterials having potential implications. The complex phenomena involved in the laser ablation process cause extreme pressure and temperature and a highly transient preferential growth of metastable phases is possible. Understanding of the nucleation phenomena of laser-produced nanoparticles in liquid is still limited and more orientated towards exploring the applicability of the nanoparticulates. The current work thus focuses on the nucleation dynamics of the high-pressure phase of TiO2 having an orthorhombic α-PbO2-like structure formed during pulsed laser ablation at the titanium–water interface. The nucleation time (10‑11 to 10‑8 s), growth velocity (maximum of ~100 nm ns‑1) and particle statistics are calculated and compared with experimentally derived particle statistics (3–180 nm). Pulsed laser ablation in liquid is also accompanied by mechanical phenomena known as cavitation bubbles. Insight into the possible role played by cavitation bubbles in the nucleation of nanoparticulates is outlined.

  8. Physico-chemical characterization of human recombinant follicle-stimulating hormone (hFSH) and its subunits by reversed-phase high-performance liquid chromatography ( RP-HPLC): comparison with pituitary hFSH reference preparation from 'National Hormone and Pituitary Program' from USA; Caracterizacao fisico-quimica da foliculotropina humana(hFSH) recombinabte e de suas subunidades, por cromatografia liquida de alta eficiencia (HPLC) em fase reversa: comparacao com a preparacao de referencia de hFSH de origem hipofisaria do ''National Hormone and Pituitary Program'' dos EUA

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Renan Fernandes

    2006-07-01

    A reversed-phase high-performance liquid chromatography (RP-HPLC) method for the qualitative and quantitative analysis of intact human folliclestimulating hormone (hFSH) was established and validated for accuracy, precision and sensitivity. Human FSH is a dimeric glycoprotein hormone widely used as a diagnostic analyte and as therapeutic product in reproductive medicine. The technique developed preserves the protein integrity, allowing the analysis of the intact heterodimeric form rather than just of its subunits, as it is the case for the majority of the conditions currently employed. This methodology has also been employed for comparing the relative hydrophobicity of pituitary, urinary and two Chinese hamster ovary (CHO)-derived hFSH preparations, as well as of two other related glycoprotein hormones of the anterior pituitary: human thyroid-stimulating hormone (hTSH) and human luteinizing hormone (hLH). The least hydrophobic of the three glycohormones analyzed was hFSH, followed by hTSH and hLH. A significant difference (p<0.005) was observed in t{sub R} between the pituitary and recombinant hFSH preparations, reflecting structural differences in their carbohydrate moieties. Two main isoforms were detected in urinary hFSH, including a form which was significantly different (p<0.005) for the pituitary and recombinant preparations. The linearity of the dose-response curve (r = 0.9965, n = 15) for this RP-HPLC methodology, as well as an inter-assay precision with relative standard deviation less than 4% for the quantification of different hFSH preparations and a sensitivity of the order of 40 ng, were demonstrated. The chromatographic behavior and relative hydrophobicity of the individual subunits of the pituitary and recombinant preparations were also analyzed. Furthermore, the accurate molecular mass of the individual hFSH subunits and of the heterodimer were simultaneously determined by matrix-assisted laser desorption ionization time-of-flight mass spectral

  9. Phase field modeling of liquid metal embrittlement

    Science.gov (United States)

    Spatschek, Robert; Wang, Nan; Karma, Alain

    2008-03-01

    Liquid metal embrittlement (LME) is a phenomenon whereby a liquid metal in contact with another, higher-melting-point polycrystalline metal, rapidly penetrates from the surface along grain boundaries. This phenomenon is known to be greatly accelerated by the application of tensile stress, resulting in the rapid propagation of intergranular cracks in normally ductile materials. Although this phenomenon has been known for a long time, it still lacks a convincing physical explanation. In particular, the relationship of LME to conventional fracture mechanics remains unclear. We investigate LME using a phenomenological three-order-parameter phase field model that describes both the short scale physics of crystal decohesion and macroscopic linear elasticity. The model reproduces expected macroscopic properties for well separated crack surfaces and additionally introduces short scale modifications for liquid layer thicknesses in the nanometric range, which depend on the interfacial and grain boundary energy as well as elastic effects. The results shed light on the relative importance of capillary phenomena and stress in the kinetics of LME.

  10. Thermomorphic phase separation in ionic liquid-organic liquid systems - conductivity and spectroscopic characterization

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Berg, Rolf W.

    2005-01-01

    Electrical conductivity, FT-Raman and NMR measurements are demonstrated as useful tools to probe and determine phase behavior of thermomorphic ionic liquid-organic liquid systems. To illustrate the methods, consecutive conductivity measurements of a thermomorphic methoxyethoxyethyl-imidazolium io...... of the components in the system, the liquid-liquid equilibrium phase diagram of the binary mixture, and signify the importance of hydrogen bonding between the ionic liquid and the hydroxyl group of the alcohol....

  11. On liquid phases in cometary nuclei

    Science.gov (United States)

    Miles, Richard; Faillace, George A.

    2012-06-01

    In this paper we review the relevant literature and investigate conditions likely to lead to melting of H2O ice, methanol (CH3OH) ice, ethane (C2H6) ice and other volatile ices in cometary nuclei. On the basis of a heat balance model which takes account of volatiles loss, we predict the formation of occasional aqueous and hydrocarbon liquid phases in subsurface regions at heliocentric distances, rh of 1-3 AU, and 5-12 AU, respectively. Low triple-point temperatures and low vapour pressures of C2H6, C3H8, and some higher-order alkanes and alkenes, favour liquid phase formation in cometary bodies at high rh. Microporosity and the formation of a stabilization crust occluding the escape of volatiles facilitate liquid-phase formation. Characteristics of the near-surface which favour subsurface melting include; low effective surface emissivity (at low rh), high amorphous carbon content, average pore sizes of ˜10 μm or less, presence of solutes (e.g. CH3OH), mixtures of C2-C6 hydrocarbons (for melting at high rh), diurnal thermal cycling, and slow rotation rate. Applying the principles of soil mechanics, capillary forces are shown to initiate pre-melting phenomena and subsequent melting, which is expected to impart considerable strength of ˜104 Pa in partially saturated layers, reducing porosity and permeability, enhancing thermal conductivity and heat transfer. Diurnal thermal cycling is expected to have a marked effect on the composition and distribution of H2O ice in the near-surface leading to frost heave-type phenomena even where little if any true melting occurs. Where melting does take place, capillary suction in the wetted zone has the potential to enhance heat transfer via capillary wetting in a low-gravity environment, and to modify surface topography creating relatively smooth flat-bottomed features, which have a tendency to be located within small depressions. An important aspect of the "wetted layer" model is the prediction that diurnal melt-freeze cycles

  12. Stable liquid crystalline phases of colloidally dispersed exfoliated layered niobates.

    Science.gov (United States)

    Nakato, Teruyuki; Miyamoto, Nobuyoshi; Harada, Akiko

    2004-01-07

    Colloidally dispersed niobium oxide nanosheets obtained by exfoliation of layered niobates HNb(3)O(8) and HTiNbO(5) formed stable liquid crystalline phases; their liquid crystallinity was dependent on the niobate species exfoliated.

  13. Intramolecular coupling as a mechanism for a liquid-liquid phase transition

    OpenAIRE

    Franzese, Giancarlo; Marqués, Manuel I.; Stanley, H. Eugene

    2003-01-01

    We study a model for water with a tunable intramolecular interaction Js, using mean-field theory and off-lattice Monte Carlo simulations. For all Js>~0, the model displays a temperature of maximum density. For a finite intramolecular interaction Js>0, our calculations support the presence of a liquid-liquid phase transition with a possible liquid-liquid critical point for water, likely preempted by inevitable freezing. For J=0, the liquid-liquid critical point disappears at T=0.

  14. Quantum Liquid Crystal Phases in Strongly Correlated Fermionic Systems

    Science.gov (United States)

    Sun, Kai

    2009-01-01

    This thesis is devoted to the investigation of the quantum liquid crystal phases in strongly correlated electronic systems. Such phases are characterized by their partially broken spatial symmetries and are observed in various strongly correlated systems as being summarized in Chapter 1. Although quantum liquid crystal phases often involve…

  15. Liquid-chromatography mass spectrometry (LC-MS) of steroid hormone metabolites and its applications

    Science.gov (United States)

    Penning, Trevor M.; Lee, Seon-Hwa; Jin, Yi; Gutierrez, Alejandro; Blair, Ian A.

    2010-01-01

    Advances in liquid chromatography-mass spectrometry (LC-MS) can be used to measure steroid hormone metabolites in vitro and in vivo. We find that LC-Electrospray Ionization (ESI)-MS using a LCQ ion trap mass spectrometer in the negative ion mode can be used to monitor the product profile that results from 5α–dihydrotestosterone(DHT)-17β-glucuronide, DHT-17β-sulfate, and tibolone-17β-sulfate reduction catalyzed by human members of the aldo-keto reductase (AKR) 1C subfamily and assign kinetic constants to these reactions. We also developed a stable-isotope dilution LC-electron capture atmospheric pressure chemical ionization (ECAPCI)-MS method for the quantitative analysis of estrone (E1) and its metabolites as pentafluorobenzyl (PFB) derivatives in human plasma in the attomole range. The limit of detection for E1-PFB was 740 attomole on column. Separations can be performed using normal-phase LC because ionization takes place in the gas phase rather than in solution. This permits efficient separation of the regioisomeric 2- and 4-methoxy-E1. The method was validated for the simultaneous analysis of plasma E2 and its metabolites: 2-methoxy-E2, 4-methoxy-E2, 16α-hydroxy-E2, estrone (E1), 2-methoxy-E1, 4-methoxy-EI, and 16α-hydroxy-E1 from 5 pg/mL to 2,000 pg/mL. Our LC-MS methods have sufficient sensitivity to detect steroid hormone levels in prostate and breast tumors and should aid their molecular diagnosis and treatment. PMID:20083198

  16. Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers

    OpenAIRE

    Blumenschein, Nicholas; Han, Daewoo; Steckl, Andrew J.

    2015-01-01

    Magnetic beads with ~1.9 µm average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for the purpose of investigating phase change of those liquid segments. The magnetic beads were externally controlled using a magnet, allowing for the beads to bridge the air valve between the adjacent liquid segments. A hydrophobic coating was applied to the inner surface of the tube to enhance the separation between two liquid segments. The applied...

  17. Liquid-phase operations at Poelitz, 1942

    Energy Technology Data Exchange (ETDEWEB)

    1942-02-10

    This report consists of three tables and accompanying comments concerning a comparison of coal hydrogenation liquid phase operations during two different periods at the Poelitz plant. The first table compares temperatures, input ratios, yield ratios, product content and quality, and efficiency for the two periods of operation as well as a theoretical calculation. Comments on the table point out that great differences are indicated in decomposition, throughput, asphalt content, solids in the letdown and pasting oil, and circulating gas quantity. Table II charts a theoretical balance for Poelitz operations converting coal to gasoline and middle oil. Table III shows a comparison between throughput or consumption figures for the oil recovery available per ton and the average Poelitz production schedule after converting to one ton available oil recovery. The table indicates that Poelitz gasification and consequent hydrogen consumption and product factor were still far above the theoretical. On the other hand, oil yield was normal. 3 tables.

  18. Liquid phase exfoliated graphene for electronic applications

    Science.gov (United States)

    Sukumaran, Sheena S.; Jinesh, K. B.; Gopchandran, K. G.

    2017-09-01

    Graphene dispersions were prepared using the liquid phase exfoliation method with three different surfactants. One surfactant was used from each of the surfactant types, anionic, cationic, and non-ionic; those used, were sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP), respectively. Raman spectroscopy was used to investigate the number of layers and the nature of any defects present in the exfoliated graphene. The yield of graphene was found to be less with the non-ionic surfactant, PVP. The deconvolution of 2D peaks at ~2700 cm-1 indicated that graphene prepared using these surfactants resulted in sheets consisting of few-layer graphene. The ratio of intensity of the D and G bands in the Raman spectra showed that edge defect density is high for samples prepared with SDBS compared to the other two, and is attributed to the smaller size of the graphene sheets, as shown in the electron micrographs. In the case of the dispersion in PVP, it is found that the sizes of the graphene sheets are highly sensitive to the concentration of the surfactant used. Here, we have made an attempt to investigate the local density of states in the graphene sheets by measuring the tunnelling current-voltage characteristics. Graphene layers have shown consistent p-type behaviour when exfoliated with SDBS and n-type behaviour when exfoliated with CTAB, with a larger band gap for graphene exfoliated using CTAB. Hence, in addition to the known advantages of liquid phase exfoliation, we found that by selecting suitable surfactants, to a certain extent it is possible to tune the band gap and determine the type of majority carriers.

  19. Supported Liquid Membrane Extraction of Anabolic Androgenic ...

    African Journals Online (AJOL)

    NJD

    Anabolic androgenic compounds, supported liquid membrane, liquid chromatography, electrospray ionization, mass spectrometry. 1. Introduction ... monitoring of some of the anabolic hormones in muscles via pentafluoropropionyl derivatization and ... androgenic steroid hormones involve the use of solid phase extraction ...

  20. Phase Change Enthalpies and Entropies of Liquid Crystals

    National Research Council Canada - National Science Library

    Acree, William E; Chickos, James S

    2006-01-01

    .... A group additivity approach used to estimate total phase change entropies of organic molecules applied to 627 of these liquid crystals is found to significantly overestimate their total phase change entropies...

  1. Liquid-liquid phase transition and glass transition in a monoatomic model system.

    Science.gov (United States)

    Xu, Limei; Buldyrev, Sergey V; Giovambattista, Nicolas; Stanley, H Eugene

    2010-01-01

    We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

  2. Supported Ionic Liquid Phase (SILP) catalysis

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco

    2006-01-01

    Applications of ionic liquids to replace conventional solvents in homogeneous transition-metal catalysis have increased significantly during the last decade. Biphasic ionic liquid/organic liquid systems offer advantages with regard to product separation, catalyst stability, and recycling but util...

  3. Methods to control phase inversions and enhance mass transfer in liquid-liquid dispersions

    Science.gov (United States)

    Tsouris, Constantinos; Dong, Junhang

    2002-01-01

    The present invention is directed to the effects of applied electric fields on liquid-liquid dispersions. In general, the present invention is directed to the control of phase inversions in liquid-liquid dispersions. Because of polarization and deformation effects, coalescence of aqueous drops is facilitated by the application of electric fields. As a result, with an increase in the applied voltage, the ambivalence region is narrowed and shifted toward higher volume fractions of the dispersed phase. This permits the invention to be used to ensure that the aqueous phase remains continuous, even at a high volume fraction of the organic phase. Additionally, the volume fraction of the organic phase may be increased without causing phase inversion, and may be used to correct a phase inversion which has already occurred. Finally, the invention may be used to enhance mass transfer rates from one phase to another through the use of phase inversions.

  4. Development of liquid phase since 1933

    Energy Technology Data Exchange (ETDEWEB)

    Rank, V.

    1944-10-23

    After the hydrogenation of brown coal had reached a certain stage, the center of hydrogenation experimental work was shifted to soft coal. A successful large-scale test was performed in 1934 on the hydrogenation of Ruhr coal. At the time of this test, suitable apparatus had been developed for the centrifuging and kilning of the residues of the coal hydrogenation industry. Foundations were simultaneously created for the erection of the first soft coal hydrogenation works, which had been started in Scholven in 1936. Tests with higher pressures, in particular with 700 atm, were undertaken in order to apply the hydrogenation utilization methods to the older coals as well. The great improvement in the hydrogenation at this high pressure resulted in the use of cheaper catalysts, replacing tin and chlorine. A higher temperature could be used at higher pressures, which in turn resulted in the greater utilization of the coal, better yields, lower asphalt content, the latter being particularly important in the utilization of residues. The gasification was less at 700 atm than at 300 atm, in spite of the high temperatures. Table 1 of this report showed results of tests with 300 and 700 atm pressures in ten-liter converters. Table 2 showed properties of the 700 atm liquid-phase products from different raw materials. Table 3 gave different methods of hydrogenation of coal. Table 4 gave the composition of hydrogenated coal and table 5 gave properties of fuel oils. Finally, the report discussed two major variants of the usual hydrogenation process, both of which used higher throughputs and less hydrogen added. One of these processes produced a larger proportion of heavy oil for naval fuel oil, and the other produced high-molecular-weight asphalts for use as briquetting binders. 5 tables

  5. Images reveal that atmospheric particles can undergo liquid-liquid phase separations

    Energy Technology Data Exchange (ETDEWEB)

    You, Yuan; Renbaum-Wolff, Lindsay; Carreras-Sospedra, Marc; Hanna, Sarah; Hiranuma, Naruki; Kamal, Saeid; Smith, Mackenzie L.; Zhang, Xiaolu; Weber, Rodney; Shilling, John E.; Dabdub, Donald; Martin, Scot T.; Bertram, Allan K.

    2012-07-30

    A large fraction of submicron atmospheric particles contains both organic material and inorganic salts. As the relative humidity cycles in the atmosphere, these mixed particles can undergo a range of phase transitions, possibly including liquid-liquid phase separation. If liquid-liquid phase separation occurs, the gas-particle partitioning of atmospheric semi-volatile organic compounds, the scattering and absorption of solar radiation, and the uptake of reactive gas species on atmospheric particles will be affected, with important implications for climate predictions. The actual occurrence of these types of phase transitions within individual atmospheric particles has been considered uncertain, in large part because of the absence of observations for real-world samples. Here, using optical and fluorescence microscopy, we observe the coexistence of two non-crystalline phases in particles generated from real-world samples collected on multiple days in Atlanta, Georgia, and in particles generated in the laboratory using atmospheric conditions. These results reveal that atmospheric particles can undergo liquid-liquid phase separations. Using a box model, we show that liquid-liquid phase separation can result in increased concentrations of gas-phase NO3 and N2O5 in the Atlanta region, due to decreased particle uptake of N2O5.

  6. A free energy study of the liquid-liquid phase transition of the Jagla ...

    Indian Academy of Sciences (India)

    Francesco Ricci

    Abstract. A fundamental understanding of pure-component liquid-liquid phase separation in network-forming fluids remains an open challenge. While considerable progress has been recently made in demonstrating the existence of such a phase transition in some models via rigorous free energy calculations, it remains ...

  7. Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers.

    Science.gov (United States)

    Blumenschein, Nicholas; Han, Daewoo; Steckl, Andrew J

    2015-09-04

    Magnetic beads with ~1.9 µm average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for the purpose of investigating phase change of those liquid segments. The magnetic beads were externally controlled using a magnet, allowing for the beads to bridge the air valve between the adjacent liquid segments. A hydrophobic coating was applied to the inner surface of the tube to enhance the separation between two liquid segments. The applied magnetic field formed an aggregate cluster of magnetic beads, capturing a certain liquid amount within the cluster that is referred to as carry-over volume. A fluorescent dye was added to one liquid segment, followed by a series of liquid transfers, which then changed the fluorescence intensity in the neighboring liquid segment. Based on the numerical analysis of the measured fluorescence intensity change, the carry-over volume per mass of magnetic beads has been found to be ~2 to 3 µl/mg. This small amount of liquid allowed for the use of comparatively small liquid segments of a couple hundred microliters, enhancing the feasibility of the device for a lab-in-tube approach. This technique of applying small compositional variation in a liquid volume was applied to analyzing the binary phase diagram between water and the surfactant C12E5 (pentaethylene glycol monododecyl ether), leading to quicker analysis with smaller sample volumes than conventional methods.

  8. Liquid Crystals - The 'Fourth' Phase of Matter

    Indian Academy of Sciences (India)

    most well-known application is the liquid crystal-display (LCD), used in watches, calculators, flat panel displays used recently even in TV sets, and so on. The anisotropic properties of liquid crystals in refractive index and dielectric constant can be exploited for the purposes of creating flat-panel displays. Usually what is done ...

  9. Intra-molecular coupling as a mechanism for a liquid-liquid phase transition

    OpenAIRE

    Franzese, Giancarlo; Marques, Manuel I.; Stanley, H. Eugene

    2001-01-01

    We study a model for water with a tunable intra-molecular interaction $J_\\sigma$, using mean field theory and off-lattice Monte Carlo simulations. For all $J_\\sigma\\geq 0$, the model displays a temperature of maximum density.For a finite intra-molecular interaction $J_\\sigma > 0$,our calculations support the presence of a liquid-liquid phase transition with a possible liquid-liquid critical point for water, likely pre-empted by inevitable freezing. For J=0 the liquid-liquid critical point dis...

  10. Transient-Liquid-Phase and Liquid-Film-Assisted Joining ofCeramics

    Energy Technology Data Exchange (ETDEWEB)

    Sugar, Joshua D.; McKeown, Joseph T.; Akashi, Takaya; Hong, SungM.; Nakashima, Kunihiko; Glaeser, Andreas M.

    2005-02-09

    Two joining methods, transient-liquid-phase (TLP) joining and liquid-film-assisted joining (LFAJ), have been used to bond alumina ceramics. Both methods rely on multilayer metallic interlayers designed to form thin liquid films at reduced temperatures. The liquid films either disappear by interdiffusion (TLP) or promote ceramic/metal interface formation and concurrent dewetting of the liquid film (LFAJ). Progress on extending the TLP method to lower temperatures by combining low-melting-point (<450 C) liquids and commercial reactive-metal brazes is described. Recent LFAJ work on joining alumina to niobium using copper films is presented.

  11. Hormones

    Science.gov (United States)

    Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs. They work ... glands, which are special groups of cells, make hormones. The major endocrine glands are the pituitary, pineal, ...

  12. Comparing two tetraalkylammonium ionic liquids. I. Liquid phase structure

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C., E-mail: mccribei@iq.usp.br [Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP (Brazil); Giles, Carlos [Departamento de Física da Matéria Condensada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP (Brazil)

    2016-06-14

    X-ray scattering experiments at room temperature were performed for the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1114}][NTf{sub 2}], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1444}][NTf{sub 2}]. The peak in the diffraction data characteristic of charge ordering in [N{sub 1444}][NTf{sub 2}] is shifted to longer distances in comparison to [N{sub 1114}][NTf{sub 2}], but the peak characteristic of short-range correlations is shifted in [N{sub 1444}][NTf{sub 2}] to shorter distances. Molecular dynamics (MD) simulations were performed for these ionic liquids using force fields available from the literature, although with new sets of partial charges for [N{sub 1114}]{sup +} and [N{sub 1444}]{sup +} proposed in this work. The shifting of charge and adjacency peaks to opposite directions in these ionic liquids was found in the static structure factor, S(k), calculated by MD simulations. Despite differences in cation sizes, the MD simulations unravel that anions are allowed as close to [N{sub 1444}]{sup +} as to [N{sub 1114}]{sup +} because anions are located in between the angle formed by the butyl chains. The more asymmetric molecular structure of the [N{sub 1114}]{sup +} cation implies differences in partial structure factors calculated for atoms belonging to polar or non-polar parts of [N{sub 1114}][NTf{sub 2}], whereas polar and non-polar structure factors are essentially the same in [N{sub 1444}][NTf{sub 2}]. Results of this work shed light on controversies in the literature on the liquid structure of tetraalkylammonium based ionic liquids.

  13. Two Coexisting Liquid Phases in Switchable Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Juan; Lao, David; Sui, Xiao; Zhou, Yufan; Nune, Satish K.; Ma, Xiang; Troy, Tyler; Ahmed, Musahid; Zhu, Zihua; Heldebrant, David J.; Yu, Xiao-Ying

    2017-08-30

    In situ time-of-flight secondary ion mass spectrometry (ToF-SIMS) coupled with a vacuum compatible microfluidic reactor, System for Analysis at Liquid Vacuum Interface (SALVI), has enabled the first spatial mapping of the switchable ionic liquids (SWILs) derived from 1,8-diazabicycloundec-7-ene (DBU) and 1-hexanol. As predicted by molecular dynamic simulations, our molecular imaging results confirmed a dynamic heterogeneous molecular structure with ionic regions (high CO2 concentration) coexisting with non-ionic regions (no CO2) where stoichiometry would indicate otherwise. Chemical speciation was also found to be more complex than initially thought, with spectral principal component analysis identifying dimers that ultimately highlight a highly complex molecular structure unique to SWILs. The spatial chemical mapping enabled by ToF-SIMS and SALVI advances the understanding of how the heterogeneous molecular structure impacts the dynamic physical and thermodynamic properties or SWILs.

  14. Liquid crystal phase behaviour of colloidal platelets in external fields

    NARCIS (Netherlands)

    Beek, David van der

    2005-01-01

    In this thesis, the liquid crystal phase behaviour of colloidal platelets in external fields is studied. We have specifically investigated the influence of morphological, gravitational, magnetic and centrifugal fields. Part I of this thesis involves sterically stabilised colloidal gibbsite

  15. Liquid-phase microextraction in a microfluidic-chip

    DEFF Research Database (Denmark)

    Payán, María D. Ramos; Jensen, Henrik; Petersen, Nickolaj J.

    2012-01-01

    In this work, a microfluidic-chip based system for liquid-phase microextraction (LPME-chip) was developed. Sample solutions were pumped into the LPME-chip with a micro-syringe pump at a flow rate of 3-4µLmin(-1). Inside the LPME chip, the sample was in direct contact with a supported liquid...

  16. Sensitive and Selective Reversed-Phase High Performance Liquid ...

    African Journals Online (AJOL)

    Methods: Pre-column sample clean-up was carried out by liquid-liquid extraction of the analytes with chloroform: isopropanol (70:30) solution after alkalization of 1000 μL sample and spiking of internal standard, morphine. The samples were chromatographed in a reversed-phase (C-18) ultra sphere silica (5μm particle size ...

  17. The liquid-liquid phase transition in dense hydrogen

    Science.gov (United States)

    Ceperley, David; Pierleoni, Carlo; Holzmann, Markus; Morales, Miguel

    The phase diagram of high pressure hydrogen is of great interest for fundamental research. A first-order phase transition in the fluid phase between a molecular insulating fluid and a monoatomic metallic fluid has been long anticipated. Recent experiments reported contrasting results about the location of the transition and theoretical results are very uncertain. We report highly accurate coupled electron-ion quantum Monte Carlo calculations of this transition, finding results that lie between the two experimental predictions, close to that measured in diamond anvil cell experiments but at 25-30 GPa higher pressure. The transition along an isotherm is signaled by a discontinuity in the specific volume, a sudden dissociation of the molecules, a jump in electrical conductivity and loss of electron localization. Funding from DOE NA DE-NA0001789 and DE-AC52-07NA27344. Computer time from PRACE and Blue Waters.

  18. The liquid to vapor phase transition in excited nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.

    2001-05-08

    For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid-vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197 Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

  19. Green aspects, developments and perspectives of liquid phase microextraction techniques.

    Science.gov (United States)

    Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

    2014-02-01

    Determination of analytes at trace levels in complex samples (e.g. biological or contaminated water or soils) are often required for the environmental assessment and monitoring as well as for scientific research in the field of environmental pollution. A limited number of analytical techniques are sensitive enough for the direct determination of trace components in samples and, because of that, a preliminary step of the analyte isolation/enrichment prior to analysis is required in many cases. In this work the newest trends and innovations in liquid phase microextraction, like: single-drop microextraction (SDME), hollow fiber liquid-phase microextraction (HF-LPME), and dispersive liquid-liquid microextraction (DLLME) have been discussed, including their critical evaluation and possible application in analytical practice. The described modifications of extraction techniques deal with system miniaturization and/or automation, the use of ultrasound and physical agitation, and electrochemical methods. Particular attention was given to pro-ecological aspects therefore the possible use of novel, non-toxic extracting agents, inter alia, ionic liquids, coacervates, surfactant solutions and reverse micelles in the liquid phase microextraction techniques has been evaluated in depth. Also, new methodological solutions and the related instruments and devices for the efficient liquid phase micoextraction of analytes, which have found application at the stage of procedure prior to chromatographic determination, are presented. © 2013 Published by Elsevier B.V.

  20. Highly Selective Continuous Gas-Phase Methoxycarbonylation of Ethylene with Supported Ionic Liquid Phase (SILP) Catalysts

    DEFF Research Database (Denmark)

    Khokarale, Santosh Govind; Garcia Suárez, Eduardo José; Fehrmann, Rasmus

    2017-01-01

    Supported ionic liquid phase (SILP) technology was applied for the first time to the Pd-catalyzed continuous, gas-phase methoxycarbonylation of ethylene to selectively produce methyl propanoate (MP) in high yields. The influence of catalyst and reaction parameters such as, for example, ionic liquid...

  1. Voice in different phases of menstrual cycle among naturally cycling women and users of hormonal contraceptives.

    Directory of Open Access Journals (Sweden)

    Irena Pavela Banai

    Full Text Available Previous studies have shown changes in women's behavior and physical appearance between the non-fertile and fertile phases of the menstrual cycle. It is assumed that these changes are regulated by fluctuations in sex hormone levels across the cycle. Receptors for sex hormones have been found on the vocal folds, suggesting a link between hormone levels and vocal fold function, which might cause changes in voice production. However, attempts to identify changes in voice production across the menstrual cycle have produced mixed results. Therefore, the purpose of this study was to investigate changes in sexually dimorphic vocal characteristics and quality of women's voices in different phases of the cycle and to compare these with users of monophasic hormonal contraception. Voice samples (vowel phonation of 44 naturally cycling women were obtained in the menstrual, late follicular (confirmed by LH surge and luteal phases, and in 20 hormonal contraceptive users across equivalent stages of the monthly cycle. Results showed that voices of naturally cycling women had higher minimum pitch in the late follicular phase compared with the other phases. In addition, voice intensity was at its lowest in the luteal phase. In contrast, there were no voice changes across the cycle in hormonal contraceptive users. Comparison between the two groups of women revealed that the naturally cycling group had higher minimum pitch in the fertile phase and higher harmonics to noise ratio in the menstrual phase. In general, present results support the assumption that sex hormones might have an effect on voice function. These results, coupled with mixed findings in previous studies, suggest that vocal changes in relation to hormonal fluctuation are subtle, at least during vowel production. Future studies should explore voice changes in a defined social context and with more free-flowing speech.

  2. Voice in different phases of menstrual cycle among naturally cycling women and users of hormonal contraceptives.

    Science.gov (United States)

    Pavela Banai, Irena

    2017-01-01

    Previous studies have shown changes in women's behavior and physical appearance between the non-fertile and fertile phases of the menstrual cycle. It is assumed that these changes are regulated by fluctuations in sex hormone levels across the cycle. Receptors for sex hormones have been found on the vocal folds, suggesting a link between hormone levels and vocal fold function, which might cause changes in voice production. However, attempts to identify changes in voice production across the menstrual cycle have produced mixed results. Therefore, the purpose of this study was to investigate changes in sexually dimorphic vocal characteristics and quality of women's voices in different phases of the cycle and to compare these with users of monophasic hormonal contraception. Voice samples (vowel phonation) of 44 naturally cycling women were obtained in the menstrual, late follicular (confirmed by LH surge) and luteal phases, and in 20 hormonal contraceptive users across equivalent stages of the monthly cycle. Results showed that voices of naturally cycling women had higher minimum pitch in the late follicular phase compared with the other phases. In addition, voice intensity was at its lowest in the luteal phase. In contrast, there were no voice changes across the cycle in hormonal contraceptive users. Comparison between the two groups of women revealed that the naturally cycling group had higher minimum pitch in the fertile phase and higher harmonics to noise ratio in the menstrual phase. In general, present results support the assumption that sex hormones might have an effect on voice function. These results, coupled with mixed findings in previous studies, suggest that vocal changes in relation to hormonal fluctuation are subtle, at least during vowel production. Future studies should explore voice changes in a defined social context and with more free-flowing speech.

  3. Liquid-Liquid Phase Transition and Glass Transition in a Monoatomic Model System

    Directory of Open Access Journals (Sweden)

    Nicolas Giovambattista

    2010-12-01

    Full Text Available We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

  4. Indication of liquid-liquid phase transition in CuZr-based melts

    DEFF Research Database (Denmark)

    Zhou, C.; Hu, L.N.; Sun, Q.J.

    2013-01-01

    We study the dynamic behavior of CuZr-based melts well above the liquidus temperature. The results show a discontinuous change in viscosity during cooling, which is attributed to an underlying liquid-liquid phase transition (LLPT) in these melts. The LLPT is further verified by thermodynamic...

  5. Surface Phases in Binary Liquid Metal Alloys

    OpenAIRE

    Tostmann, Holger; DiMasi, Elaine; Shpyrko, Oleg G.; Ocko, Ben M.; Pershan, Peter S.; Deutsch, Moshe

    2004-01-01

    Surface sensitive x-ray scattering techniques with atomic scale resolution are employed to investigate the microscopic structure of the surface of three classes of liquid binary alloys: (i) Surface segregation in partly miscible binary alloys as predicted by the Gibbs adsorption rule is investigated for Ga-In. The first layer consists of a supercooled In monolayer and the bulk composition is reached after about two atomic diameters. (ii) The Ga-Bi system displays a wetting transition at a cha...

  6. Continuation of growth hormone therapy versus placebo in transition-phase patients with growth hormone deficiency

    DEFF Research Database (Denmark)

    Jørgensen, Jens; Nørrelund, Helene; Vahl, Nina

    2002-01-01

    In a placebo-controlled, parallel study of 18 patients with a mean age of 20 years who had confirmed growth hormone (GH) deficiency, we evaluated body composition, insulin sensitivity, and glucose turnover at baseline (when all were receiving GH replacement); after 12 months of continued GH therapy...

  7. Coexisting liquid phases underlie nucleolar sub-compartments

    Science.gov (United States)

    Feric, Marina; Vaidya, Nilesh; Harmon, Tyler S.; Mitrea, Diana M.; Zhu, Lian; Richardson, Tiffany M.; Kriwacki, Richard W.; Pappu, Rohit V.; Brangwynne, Clifford P.

    2016-01-01

    Summary The nucleolus and other ribonucleoprotein (RNP) bodies are membrane-less organelles that appear to assemble through phase separation of their molecular components. However, many such RNP bodies contain internal sub-compartments, and the mechanism of their formation remains unclear. Here, we combine in vivo and in vitro studies, together with computational modeling, to show that sub-compartments within the nucleolus represent distinct, coexisting liquid phases. Consistent with their in vivo immiscibility, purified nucleolar proteins phase separate into droplets containing distinct non-coalescing phases that are remarkably similar to nucleoli in vivo. This layered droplet organization is caused by differences in the biophysical properties of the phases – particularly droplet surface tension – which arises from sequence-encoded features of their macromolecular components. These results suggest that phase separation can give rise to multilayered liquids that may facilitate sequential RNA processing reactions in a variety of RNP bodies. PMID:27212236

  8. A superconductor to superfluid phase transition in liquid metallic hydrogen.

    Science.gov (United States)

    Babaev, Egor; Sudbø, Asle; Ashcroft, N W

    2004-10-07

    Although hydrogen is the simplest of atoms, it does not form the simplest of solids or liquids. Quantum effects in these phases are considerable (a consequence of the light proton mass) and they have a demonstrable and often puzzling influence on many physical properties, including spatial order. To date, the structure of dense hydrogen remains experimentally elusive. Recent studies of the melting curve of hydrogen indicate that at high (but experimentally accessible) pressures, compressed hydrogen will adopt a liquid state, even at low temperatures. In reaching this phase, hydrogen is also projected to pass through an insulator-to-metal transition. This raises the possibility of new state of matter: a near ground-state liquid metal, and its ordered states in the quantum domain. Ordered quantum fluids are traditionally categorized as superconductors or superfluids; these respective systems feature dissipationless electrical currents or mass flow. Here we report a topological analysis of the projected phase of liquid metallic hydrogen, finding that it may represent a new type of ordered quantum fluid. Specifically, we show that liquid metallic hydrogen cannot be categorized exclusively as a superconductor or superfluid. We predict that, in the presence of a magnetic field, liquid metallic hydrogen will exhibit several phase transitions to ordered states, ranging from superconductors to superfluids.

  9. Origins of Kerr phase and orientational phase in polymer-dispersed liquid crystal

    Science.gov (United States)

    Chang, Chia-Ming; Lin, Yi-Hsin; Reshetnyak, Victor; Park, Chui Ho; Manda, Ramesh; Lee, Seung Hee

    2017-08-01

    The anisotropic properties of nematic liquid crystals result in polarization dependency which leads to requirement of at least a polarizer in liquid crystal photonic devices. To develop polarizer free phase modulation, Kerr effect is one of the path. The phase modulation in polymer dispersed liquid crystals (PDLCs) is shown to have two parts: Kerr phase, which is the optical phase modulation linearly proportional to a square of electric field, and orientational phase. However, many puzzles are still under investigation: the origins of Kerr phase, the relation between Kerr phase and orientational phase, and how two-steps of electro-optical (EO) response relates to Kerr phase and orientational phase. We investigated the origins of Kerr phase and orientational phase in PDLC and their connection to two-step EO response. In our study, the Kerr phase is a result of LC orientation in the center of LC droplets. The orientational phase attribute to orientation of LC molecules near LC-polymer interfaces. The two phase in PDLC samples are adjustable depending on droplet size. We also found that two-steps EO response existing in small droplet (<33 nm) is related to Kerr phase and orientational phase. A modified PDLC model related to the Kerr phase and orientational phase is also proposed. Besides the conventional features of PDLC, such as polarization independent optical phase shift and response time independent of cell gap, we believe the Kerr phase and orientational phase with different response times ( msec) in PDLC pave a way for designing versatile photonic devices with pure optical phase modulation.

  10. Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-01-01

    A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

  11. Two-phase flow characteristics of liquid oxygen flow in low pressure liquid rocket engine

    Energy Technology Data Exchange (ETDEWEB)

    Namkyung Cho; Youngmog Kim [Korea Aerospace Research Inst., Control Systems Dept., Daejeon (Korea); Seunghan Kim [Korea Aerospace Research Inst., Engine Dept., Daejeon (Korea); Sangkwon Jeong; Jeheon Jung [Korea Advanced Inst. of Science and Technology, Dept. of Mechanical Engineering, Daejeon (Korea)

    2004-08-01

    In most cryogenic liquid rocket engines, liquid oxygen manifold and injector are not thermally insulated from room temperature environment for the purpose of reducing system complexity and weight. This feature of cryogenic liquid supply system results in the situation that liquid oxygen flow is vaporized especially in the vicinity of the manifold and the injector wall. The transient two-phase flow tendency is severe for low combustion pressure rocket engine without using turbo-pump. This paper focuses on the two-phase flow phenomena of liquid oxygen in low combustion pressure rocket engine. The KSR-III (Korea Sounding Rocket) engine test data is thoroughly analyzed to estimate the vapor fraction of liquid oxygen flow near the engine manifold and the injector. During the cold flow and the combustion tests of the KSR-III Engine, the static and dynamic pressures are measured at the engine inlet, the liquid oxygen manifold and the combustion chamber. The manifold outer wall and the inner wall temperatures are also measured. In this paper, we present the experimental investigation on the vapor generation, the vapor mass fraction, and the boiling characteristics of the liquid oxygen flow in the engine manifold and injector. (Author)

  12. A novel urea-functionalized surface-confined octadecylimidazolium ionic liquid silica stationary phase for reversed-phase liquid chromatography.

    Science.gov (United States)

    Zhang, Mingliang; Tan, Ting; Li, Zhan; Gu, Tongnian; Chen, Jia; Qiu, Hongdeng

    2014-10-24

    One-pot synthesis of surface-confined ionic liquid functionalized silica spheres was proposed using N-(3-aminopropyl)imidazole, γ-isopropyltriethoxysilane and 1-bromooctadecane as starting materials. The surface modification of the silica spheres was successful with a high surface density of octadecylimidazolium, enabling the utilization of this new urea-functionalized ionic liquid-grafted silica material as stationary phase for high-performance liquid chromatography in reversed-phase mode. The long aliphatic chain combined with the multiple polar group embedded in the ligands imparted the new stationary phase fine selectivity towards PAH isomers and polar aromatics and higher affinity for phenolic compounds. The unique features of the new material, especially the effect of the urea group on the retention were elucidated by mathematic modeling. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Insight into solid-liquid phase transfer catalyzed synthesis of ...

    Indian Academy of Sciences (India)

    2-Methyl-4-chlorophenoxy propionic acid (Mecoprop) is a widely used household herbicide. In the current work, a simple synthetic method is developed for Mecoprop methyl ester using solid-liquid phase transfer catalysis (S-L PTC) with K₂CO₃ as mild base and toluene as solvent. Conversion of 95% was achieved with ...

  14. Acidic ionic liquids for n-alkane isomerization in a liquid-liquid or slurry-phase reaction mode

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.; Hager, V.; Geburtig, D.; Kohr, C.; Wasserscheid, P. [Erlangen-Nuernberg Univ. (Germany). Lehrstuhl fuer Chemische Reaktionstechnik; Haumann, M. [Chemical Reaction Engineering, FAU Busan Campus, Korea (Korea, Republic of)

    2011-07-01

    Highly acidic ionic liquid (IL) catalysts offer the opportunity to convert n-alkanes at very low reaction temperatures. The results of IL catalyzed isomerization and cracking reactions of pure n-octane are presented. Influence of IL composition, [C{sub 4}C{sub 1}Im]Cl / AlCl{sub 3} / H{sub 2}SO{sub 4} and [C{sub 4}C{sub 1}Im]Cl / AlCl{sub 3} / 1-chlorooctane, on catalyst activity and selectivities to branched alkanes was investigated. Acidic chloroaluminate IL catalysts form liquid-liquid biphasic systems with unpolar organic product mixtures. Thus, recycling of the acidic IL is enabled by simple phase separation in the liquid-liquid biphasic reaction mode or the IL can be immobilized on an inorganic support with a large specific surface area. These supported ionic liquid phase (SILP) catalysts offer the advantage to get a macroscopically heterogeneous system while still preserving all benefits of the homogeneous catalyst which can be used for the slurry-phase n-alkane isomerization. The interaction of the solid support and acidic IL influences strongly the catalytic activity. (orig.)

  15. Liquid-ordered phases induced by cholesterol: a compendium of binary phase diagrams.

    Science.gov (United States)

    Marsh, Derek

    2010-03-01

    Mixtures of phospholipids with cholesterol are able to form liquid-ordered phases that are characterised by short-range orientational order and long-range translational disorder. These L(o)-phases are distinct from the liquid-disordered, fluid L(alpha)-phases and the solid-ordered, gel L(beta)-phases that are assumed by the phospholipids alone. The liquid-ordered phase can produce spatially separated in-plane fluid domains, which, in the form of lipid rafts, are thought to act as platforms for signalling and membrane sorting in cells. The areas of domain formation are defined by the regions of phase coexistence in the phase diagrams for the binary mixtures of lipid with cholesterol. In this paper, the available binary phase diagrams of lipid-cholesterol mixtures are all collected together. It is found that there is not complete agreement between different determinations of the phase diagrams for the same binary mixture. This can be attributed to the indirect methods largely used to establish the phase boundaries. Intercomparison of the various data sets allows critical assessment of which phase boundaries are rigorously established from direct evidence for phase coexistence. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Profile of MIBI Liquid Phase Radiopharmaceutical for Myocardial Imaging

    Directory of Open Access Journals (Sweden)

    I. Daruwati

    2016-04-01

    Full Text Available The 99mTc-MIBI radiopharmaceutical has been used innuclear medicine in Indonesia for myocardial imaging. BATAN researchers have mastered the technology to manufacture MIBI as a liophylized kit. A reformulation of MIBI radiopharmaceutical has been conducted to improve the stability of the kit especially in the liquid-phase kit. Basically, radiopharmaceuticals in liquid form are not different from the dry kit. However in the manufacturing of liquid-phase kit, lyophilization process was not done. To improve the stability of liquid kit, a reformulation of the components was conducted by using two separate vials (Formulation 2 and the characteristics were compared with the one-vial formulation (Formulation 1.The MIBI Formulation 2 consists of two vials, vial A containing 0.06 mg of SnCl2 2H2O and 2.6 mg Sodium Citrate 2H2O and vial B containing 0.5 mg of [Cu(MIBI4]BF4, 1 mg of cysteine hydrochloride, and 20 mg of mannitol.The purposes of this study wereto determine the stability of two different formulations of MIBI as a liquid-phase kit, to compare theirstability in different storage condition such as in refrigerator and freezer, and to compare the ratio of activities attained between target and nontargetorgans after injection to animal model. As a diagnostic agent, MIBI was reconstituted with Technetium-99m as radionuclide tracer to 99mTc-MIBI labeled compound. The radiochemical purity of 99mTc-MIBI was determined by chromatography method using alumina thin-layer chromatography paper as the stationary phase and ethanol 95% as the mobile phase. The results showed MIBI Formulation 2 has a higher stability than Formulation 1. Formulation 2 also maintaineda 96.68%radiochemical purity under 52-day storage and attainedatarget-to-nontarget activity ratio of 8.22.

  17. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    of boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless......Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition...... steel as base material. The stainless base powders were added different amounts and types of boride and sintered in hydrogen at different temperatures and times in a laboratory furnace. During sintering the outlet gas was analyzed and subsequently related to the obtained microstructure. Thermodynamic...

  18. Effect of Foam on Liquid Phase Mobility in Porous Media

    DEFF Research Database (Denmark)

    Eftekhari, Ali Akbar; Farajzadeh, R.

    2017-01-01

    We investigate the validity of the assumption that foam in porous media reduces the mobility of gas phase only and does not impact the liquid-phase mobility. The foam is generated by simultaneous injection of nitrogen gas and a surfactant solution into sandstone cores and its strength is varied...... by changing surfactant type and concentration. We find, indeed, that the effect of foam on liquid-phase mobility is not pronounced and can be ignored. Our new experimental results and analyses resolve apparent discrepancies in the literature. Previously, some researchers erroneously applied relative...... permeability relationships measured at small to moderate capillary numbers to foam floods at large capillary number. Our results indicate that the water relative permeability in the absence of surfactant should be measured with the capillary pressure ranging up to values reached during the foam floods...

  19. Liquid-liquid phase separation of freely falling undercooled ternary Fe-Cu-Sn alloy

    Science.gov (United States)

    Wang, W. L.; Wu, Y. H.; Li, L. H.; Zhai, W.; Zhang, X. M.; Wei, B.

    2015-11-01

    The active modulation and control of the liquid phase separation for high-temperature metallic systems are still challenging the development of advanced immiscible alloys. Here we present an attempt to manipulate the dynamic process of liquid-liquid phase separation for ternary Fe47.5Cu47.5Sn5 alloy. It was firstly dispersed into numerous droplets with 66 ~ 810 μm diameters and then highly undercooled and rapidly solidified under the containerless microgravity condition inside drop tube. 3-D phase field simulation was performed to explore the kinetic evolution of liquid phase separation. Through regulating the combined effects of undercooling level, phase separation time and Marangoni migration, three types of separation patterns were yielded: monotectic cell, core shell and dispersive structures. The two-layer core-shell morphology proved to be the most stable separation configuration owing to its lowest chemical potential. Whereas the monotectic cell and dispersive microstructures were both thermodynamically metastable transition states because of their highly active energy. The Sn solute partition profiles of Fe-rich core and Cu-rich shell in core-shell structures varied only slightly with cooling rate.

  20. Liquid-liquid phase separation of freely falling undercooled ternary Fe-Cu-Sn alloy

    Science.gov (United States)

    Wang, W .L.; Wu, Y. H.; Li, L. H.; Zhai, W.; Zhang, X. M.; Wei, B.

    2015-01-01

    The active modulation and control of the liquid phase separation for high-temperature metallic systems are still challenging the development of advanced immiscible alloys. Here we present an attempt to manipulate the dynamic process of liquid-liquid phase separation for ternary Fe47.5Cu47.5Sn5 alloy. It was firstly dispersed into numerous droplets with 66 ~ 810 μm diameters and then highly undercooled and rapidly solidified under the containerless microgravity condition inside drop tube. 3-D phase field simulation was performed to explore the kinetic evolution of liquid phase separation. Through regulating the combined effects of undercooling level, phase separation time and Marangoni migration, three types of separation patterns were yielded: monotectic cell, core shell and dispersive structures. The two-layer core-shell morphology proved to be the most stable separation configuration owing to its lowest chemical potential. Whereas the monotectic cell and dispersive microstructures were both thermodynamically metastable transition states because of their highly active energy. The Sn solute partition profiles of Fe-rich core and Cu-rich shell in core-shell structures varied only slightly with cooling rate. PMID:26552711

  1. Measurement of vapor-liquid-liquid phase equilibrium-Equipment and results

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; von Solms, Nicolas; Richon, Dominique

    2015-01-01

    There exists a need for new accurate and reliable experimental data, preferably with full characterization of all the phases present in equilibrium. The need for high-quality experimental phase equilibrium data is the case for the chemical industry in general. All areas deal with processes whose...... optimization is dependent on phase equilibrium data.The objective of this work is to provide experimental data for hydrocarbon systems with polar chemicals such as alcohols, glycols and water. A new experimental equipment was designed and constructed for measurement of multi-phase equilibrium in hydrocarbon......-water-gas hydrate inhibitor systems, at temperatures ranging from 283 to 353 K and at pressures up to 40 MPa. The core of the equipment is an equilibrium cell, equipped with sapphire windows and connected to an analytical system by capillary samplers.New vapor-liquid-liquid equilibrium data are reported for methane...

  2. Water Phase Diagram Is Significantly Altered by Imidazolium Ionic Liquid

    DEFF Research Database (Denmark)

    Chaban, V. V.; Prezhdo, O. V.

    2014-01-01

    We report unusually large changes in the boiling temperature, saturated vapor pressure, and structure of the liquid-vapor interface for a range of 1-butyl-3-methyl tetrafluoroborate, [C4C1IM][BF4]-water mixtures. Even modest molar fractions of [C4C1IM][BF4] significantly affect the phase behavior...... of water, as represented, for instance, by strong negative deviations from Raoult's law, extending far beyond the standard descriptions. The investigation was carried out using classical molecular dynamics employing a specifically refined force field. The changes in the liquid-vapor interface and saturated...

  3. String theory, quantum phase transitions, and the emergent Fermi liquid.

    Science.gov (United States)

    Cubrović, Mihailo; Zaanen, Jan; Schalm, Koenraad

    2009-07-24

    A central problem in quantum condensed matter physics is the critical theory governing the zero-temperature quantum phase transition between strongly renormalized Fermi liquids as found in heavy fermion intermetallics and possibly in high-critical temperature superconductors. We found that the mathematics of string theory is capable of describing such fermionic quantum critical states. Using the anti-de Sitter/conformal field theory correspondence to relate fermionic quantum critical fields to a gravitational problem, we computed the spectral functions of fermions in the field theory. By increasing the fermion density away from the relativistic quantum critical point, a state emerges with all the features of the Fermi liquid.

  4. Plasmas in Multiphase Media: Bubble Enhanced Discharges in Liquids and Plasma/Liquid Phase Boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Kushner, Mark Jay [University of Michigan

    2014-07-10

    In this research project, the interaction of atmospheric pressure plasmas with multi-phase media was computationally investigated. Multi-phase media includes liquids, particles, complex materials and porous surfaces. Although this investigation addressed fundamental plasma transport and chemical processes, the outcomes directly and beneficially affected applications including biotechnology, medicine and environmental remediation (e.g., water purification). During this project, we made advances in our understanding of the interaction of atmospheric pressure plasmas in the form of dielectric barrier discharges and plasma jets with organic materials and liquids. We also made advances in our ability to use computer modeling to represent these complex processes. We determined the method that atmospheric pressure plasmas flow along solid and liquid surfaces, and through endoscopic like tubes, deliver optical and high energy ion activation energy to organic and liquid surfaces, and produce reactivity in thin liquid layers, as might cover a wound. We determined the mechanisms whereby plasmas can deliver activation energy to the inside of liquids by sustaining plasmas in bubbles. These findings are important to the advancement of new technology areas such as plasma medicine

  5. Thermal vibrational convection in a two-phase stratified liquid

    Science.gov (United States)

    Chang, Qingming; Alexander, J. Iwan D.

    2007-05-01

    The response of a two-phase stratified liquid system subject to a vibration parallel to an imposed temperature gradient is analyzed using a hybrid thermal lattice Boltzmann method (HTLB). The vibrations considered correspond to sinusoidal translations of a rigid cavity at a fixed frequency. The layers are thermally and mechanically coupled. Interaction between gravity-induced and vibration-induced thermal convection is studied. The ability of the applied vibration to enhance the flow, heat transfer and interface distortion is investigated. For the range of conditions investigated, the results reveal that the effect of the vibrational Rayleigh number and vibrational frequency on a two-phase stratified fluid system is much different from that for a single-phase fluid system. Comparisons of the response of a two-phase stratified fluid system with a single-phase fluid system are discussed. To cite this article: Q. Chang, J.I.D. Alexander, C. R. Mecanique 335 (2007).

  6. Rapid and reliable steroid hormone profiling in Tursiops truncatus blubber using liquid chromatography tandem mass spectrometry (LC-MS/MS).

    Science.gov (United States)

    Boggs, Ashley S P; Schock, Tracey B; Schwacke, Lori H; Galligan, Thomas M; Morey, Jeanine S; McFee, Wayne E; Kucklick, John R

    2017-08-01

    Monitoring of marine mammal steroid hormone status using matrices alternative to blood is desirable due to the ability to remotely collect samples, which minimizes stress to the animal. However, measurement techniques in alternative matrices such as blubber described to date are limited in the number and types of hormones measured. Therefore, a new method using bead homogenization to QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction, C18 post extraction cleanup and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to the measurement of hormone suites in bottlenose dolphin blubber. Validations were conducted in blubber from fresh dead stranded bottlenose dolphin. The final method consisting of two LC separations and garnet bead homogenization was tested for extraction efficiencies. Steroids were separated using a biphenyl column for reproductive hormones and C18 column for corticosteroids. Three hormones previously noted in blubber, testosterone, progesterone, and cortisol, were quantified in addition to previously unmeasured androstenedione, 17-hydroxyprogesterone, 11-deoxycortisol, 11-deoxycorticosterone, and cortisone in a single sample (0.4 g blubber). Extraction efficiencies of all hormones from blubber ranged from 84% to 112% and all RSDs were comparable to those reported using immunoassay methods (< 15%). The method was successfully applied to remote biopsied blubber samples to measure baseline hormone concentrations. Through this method, increased coverage of steroid hormone pathways from a single remotely collected sample potentially enhances the ability to interpret biological phenomena such as reproduction and stress in wild dolphin populations. Graphical abstract The steroid hormone profile is quantifiable from a single sample of bottlenose dolphin blubber using liquid chromatography tandem mass spectrometry. This profile can be applied to remotely collected dart biopsies and be used to

  7. Enzalutamide monotherapy: Phase II study results in patients with hormone-naive prostate cancer

    DEFF Research Database (Denmark)

    Tombal, Bertrand; Borre, Michael; Rathenborg, Per

    2013-01-01

    studies that exclusively enrolled patients with CRPC receiving androgen deprivation therapy (ie, testosterone (T) levels #50 ng/dL), this phase II study assessed the efficacy and safety of ENZA monotherapy in patients who had never received hormone therapy; presenting with non-castrate T levels ($230 ng...

  8. Powder metallurgy: Solid and liquid phase sintering of copper

    Science.gov (United States)

    Sheldon, Rex; Weiser, Martin W.

    1993-01-01

    Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

  9. Preconcentration in gas or liquid phases using adsorbent thin films

    Directory of Open Access Journals (Sweden)

    Antonio Pereira Nascimento Filho

    2006-03-01

    Full Text Available The possibility of preconcentration on microchannels for organic compounds in gas or liquid phases was evaluated. Microstructures with different geometries were mechanically machined using poly(methyl methacrylate - PMMA as substrates and some cavities were covered with cellulose. The surfaces of the microchannels were modified by plasma deposition of hydrophilic or hydrophobic films using 2-propanol and hexamethyldisilazane (HMDS, respectively. Double layers of HMDS + 2-propanol were also used. Adsorption characterization was made by Quartz Crystal Measurements (QCM technique using reactants in a large polarity range that showed the adsorption ability of the structures depends more on the films used than on the capillary phenomena. Cellulose modified by double layer film showed a high retention capacity for all gaseous compounds tested. However, structures without plasma deposition showed low retention capacity. Microchannels modified with double layers or 2-propanol plasma films showed higher retention than non-modified ones on gas or liquid phase.

  10. Liquid-Phase Back mixing in Bubble Columns

    Directory of Open Access Journals (Sweden)

    Burhan S. Abdulrazak

    2013-05-01

    Full Text Available Liquid-phase axial dispersion coefficients have been measured for air-water system in bubble columns of 10, 15 and 30 cm diameter. The experiments are carried out using a transient method (the tracer response method.  Dispersion coefficient is obtained by adjusting the experimental profiles of tracer concentration with the predictions of the model. The experimental results show that one-dimensional axial dispersion coefficient, Dax,L, reveal strong scale dependence. Backmixing of liquid phase increases with the increase of reactor diameter and superficial gas velocity.  Axial dispersion coefficient for large column reactors can be easily predicted from the developed relation . Comparison of calculated with the experimental data and with the published data of other authors shows good agreement which ensure the reliability and confusability of the adopted correlations to be used in further design and scale-up purposes. 

  11. On some liquid crystalline phases exhibited by compounds made of ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... This system exhibits the biaxial smectic A phase down to 30°C. Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmAdb liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bilayer smectic structure ...

  12. A fundamental study of liquid phase particle breakup. Revision

    Science.gov (United States)

    1984-12-01

    Combustion efficiency of aluminized propellants in solid rocket motors is reduced by incomplete aluminum combustion and two-phase nozzle flow losses. Combustion of these propellants can produce large Al/Al2O3 agglomerates. As a direct result of agglomerate breakup, the aluminum combustion rate is increased, and the thermal energy released is more efficiently transferred into exhaust kinetic energy. This research sought to obtain physical data to characterize the mechanisms of aerodynamic droplet breakup. Experiments have been completed in which conventional liquids and a liquid metal (mercury) was studied. The primary goal of the conventional liquid experiments was to examine the effect of liquid properties (viscosity and surface tension) on the breakup mechanism, time scale, and fragment size distribution. The goal of the mercury experiments was to examine the effect of the much higher surface tension more characteristic of liquid aluminum. A key element of the experimental effort is the use of nonintrusive laser diagnostics including pulsed laser holography (PLH) and laser Doppler velocimetry (LDV). The exceptional temporal and spatial resolution of PLH provided the ability to resolve the mechanism of breakup and the size distribution of the fragments. LDV was used to determine drop velocity distributions along the nozzle revealing the rapid acceleration of the flattened droplets and then, surprisingly, the milder acceleration of the fragments.

  13. Phase transitions and transient liquid-phase sintering in calcium-substituted lanthanum chromite

    Energy Technology Data Exchange (ETDEWEB)

    Chick, L.A.; Liu, J.; Stevenson, J.W.; Armstrong, T.R.; McCready, D.E.; Maupin, G.D.; Coffey, G.W.; Coyle, C.A. [Pacific Northwest National Lab., Richland, WA (United States). Materials and Chemical Sciences Dept.

    1997-08-01

    This paper investigates sintering and phase transitions of La{sub 0.7}Ca{sub x}CrO{sub 3} (0.25 {le} x {le} 0.35), a material useful as electrical interconnections in solid oxide fuel cells. Heating of the quenched, metastable single-phase chromite resulted in exsolution of CaCrO{sub 4} due to Ca solubility limitations below 1,200 C. A transient liquid phase formed between 850 and 1,000 C as the CaCrO{sub 4} melted, causing partial densification in materials having 0.25 < x < 0.30. A slight increase in Ca content induced an additional liquid-phase sintering event, likely due to melting of Ca{sub 3}(CrO{sub 4}){sub 2}, which facilitated near-complete densification by 1,250 C. After enhancing sintering, the secondary phases redissolved into the chromite.

  14. Stability of thin emulsion film between two oil phases with a viscoelastic liquid-liquid interface.

    Science.gov (United States)

    Narsimhan, Ganesan

    2009-02-15

    The viscoelastic properties of adsorbed protein layer in food emulsions and foams are important in providing stability to such systems. Linear stability analysis for a protein stabilized aqueous film sandwiched between two semi-infinite oil phases with a viscoelastic liquid-liquid interface is presented. The interfacial dilatational and shear viscoelastic properties are described by Maxwell models. The aqueous film is found to be more stable for smaller values of dilatational (shear) relaxation times and larger values of interfacial dilatational (shear) viscosities. The asymptotic values of maximum growth coefficient for very large and very small values of interfacial dilatational (shear) viscosities were found to be independent of relaxation times and correspond to those for immobile and fully mobile liquid-liquid interfaces respectively. The aqueous film is shown to be more stable for larger viscosities of the oil phase with the maximum growth coefficient approaching zero as the ratio of viscosities of oil and aqueous phases approach very large values and an asymptotic value corresponding to that for a foam film for very small viscosity ratios.

  15. CO2 Capture with Liquid-Liquid Phase Change Solvents: A Thermodynamic Study

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; Fosbøl, Philip Loldrup; von Solms, Nicolas

    2017-01-01

    Extended UNIQUAC thermodynamic framework was implemented in this work to model the aqueous blend of N, N-Diethylethanolamine (DEEA) and N-Methyl-1,3-diaminopropane (MAPA) for CO2 capture. The model parameters were estimated first for the two ternary systems, H2O-DEEA-CO2 and H2O-MAPA-CO2, followed...... by the quaternary H2O-DEEAMAPA-CO2 system which gives liquid-liquid phase split when reacted with carbon dioxide. A total of 94 model parameters and 6 thermodynamic properties were fitted to approximately 1500 equilibrium and thermal experimental data consisting of pureamine vapor pressure (Pvap), vapor...

  16. Communication: Protein dynamical transition vs. liquid-liquid phase transition in protein hydration water

    Science.gov (United States)

    Schirò, Giorgio; Fomina, Margarita; Cupane, Antonio

    2013-09-01

    In this work, we compare experimental data on myoglobin hydrated powders from elastic neutron scattering, broadband dielectric spectroscopy, and differential scanning calorimetry. Our aim is to obtain new insights on the connection between the protein dynamical transition, a fundamental phenomenon observed in proteins whose physical origin is highly debated, and the liquid-liquid phase transition (LLPT) possibly occurring in protein hydration water and related to the existence of a low temperature critical point in supercooled water. Our results provide a consistent thermodynamic/dynamic description which gives experimental support to the LLPT hypothesis and further reveals how fundamental properties of water and proteins are tightly related.

  17. Rapid and sensitive hormonal profiling of complex plant samples by liquid chromatography coupled to electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Müller Maren

    2011-11-01

    Full Text Available Abstract Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific developmental pathways and physiological responses. Due to the presence of hormones at very low concentrations in plant tissues (10-9 M to 10-6 M and their different chemistries, the development of a high-throughput and comprehensive method for the determination of hormones is challenging. Results The present work reports a rapid, specific and sensitive method using ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UPLC/ESI-MS/MS to analyze quantitatively the major hormones found in plant tissues within six minutes, including auxins, cytokinins, gibberellins, abscisic acid, 1-amino-cyclopropane-1-carboxyic acid (the ethylene precursor, jasmonic acid and salicylic acid. Sample preparation, extraction procedures and UPLC-MS/MS conditions were optimized for the determination of all plant hormones and are summarized in a schematic extraction diagram for the analysis of small amounts of plant material without time-consuming additional steps such as purification, sample drying or re-suspension. Conclusions This new method is applicable to the analysis of dynamic changes in endogenous concentrations of hormones to study plant developmental processes or plant responses to biotic and abiotic stresses in complex tissues. An example is shown in which a hormone profiling is obtained from leaves of plants exposed to salt stress in the aromatic plant, Rosmarinus officinalis.

  18. Enzalutamide monotherapy: Phase II study results in patients with hormone-naive prostate cancer

    DEFF Research Database (Denmark)

    Tombal, Bertrand; Borre, Michael; Rathenborg, Per Zier

    2013-01-01

    studies that exclusively enrolled patients with CRPC receiving androgen deprivation therapy (ie, testosterone (T) levels #50 ng/dL), this phase II study assessed the efficacy and safety of ENZA monotherapy in patients who had never received hormone therapy; presenting with non-castrate T levels ($230 ng......Background: Enzalutamide (ENZA) is an oral androgen receptor inhibitor that has been approved in the US and shown to increase overall survival by 4.8 months over a placebo (HR,0.63) in patients with metastatic castration resistant prostate cancer (CRPC) previously treated with docetaxel (Scher et....../dL). Methods: This was a 25-wk, open-label, single-arm study of patients with hormone-naïve, histologically confirmed prostate cancer (all stages) requiring hormonal treatment, an ECOG PS score of 0,and a life expectancy .1 y. All patients received ENZA 160 mg/d without concomitment castration. Primary endpoint...

  19. Morphologies of aerosol particles consisting of two liquid phases

    Science.gov (United States)

    Song, Mijung; Marcolli, Claudia; Krieger, Ulrich; Peter, Thomas

    2013-04-01

    Recent studies have shown that liquid-liquid phase separation (LLPS) might be a common feature in mixed organic/ammonium sulfate (AS)/H2O particles. Song et al. (2012) observed that in atmospheric relevant organic/AS/H2O mixtures LLPS always occurred for organic aerosol compositions with O:C appeared for O:C > 0.80. The composition of the organic fraction and the mixing state of aerosol particles may influence deliquescence relative humidity (DRH) and efflorescence relative humidity (ERH) of inorganic salts during RH cycles and also aerosol morphology. In order to determine how the deliquescence and efflorescence of AS in mixed organic/AS/H2O particles is influenced by LLPS and to identify the corresponding morphologies of the particles, we subjected organic/AS/H2O particles deposited on a hydrophobically coated substrate to RH cycles and observed the phase transitions using optical microscopy and Raman spectroscopy. In this study, we report results from 21 organic/AS/H2O systems with O:C ranging from 0.55 - 0.85 covering aliphatic and aromatic oxidized compounds. Eight systems did not show LLPS for all investigated organic-to-inorganic ratios, nine showed core-shell morphology when present in a two-liquid-phases state and four showed both, core-shell or partially engulfed configurations depending on the organic-to-inorganic ratio. While AS in aerosol particles with complete LLPS showed almost constant values of ERH = 44 ± 4 % and DRH = 77 ± 2 %, a strong reduction or complete inhibition of efflorescence occurred for mixtures that did not exhibit LLPS. To confirm these findings, we performed supplementary experiments on levitated particles in an electrodynamic balance and compared surface and interfacial tensions of the investigated mixtures. Reference Song, M., C. Marcolli, U. K. Krieger, A. Zuend, and T. Peter (2012), Liquid-liquid phase separation in aerosol particles: Dependence on O:C, organic functionalities, and compositional complexity, Geophys. Res. Lett

  20. Recent advances in liquid-phase separations for clinical metabolomics.

    Science.gov (United States)

    Kohler, Isabelle; Giera, Martin

    2017-01-01

    Over the last decades, several technological improvements have been achieved in liquid-based separation techniques, notably, with the advent of fully porous sub-2 μm particles and superficially porous sub-3 μm particles, the comeback of supercritical fluid chromatography, and the development of alternative chromatographic modes such as hydrophilic interaction chromatography. Combined with mass spectrometry, these techniques have demonstrated their added value, substantially increasing separation efficiency, selectivity, and speed of analysis. These benefits are essential in modern clinical metabolomics typically involving the study of large-scale sample cohorts and the analysis of thousands of metabolites showing extensive differences in physicochemical properties. This review presents a brief overview of the recent developments in liquid-phase separation sciences in the context of clinical metabolomics, focusing on increased throughput as well as metabolite coverage. Relevant metabolomics applications highlighting the benefits of ultra-high performance liquid chromatography, core-shell technology, high-temperature liquid chromatography, capillary electrophoresis, supercritical fluid chromatography, and hydrophilic interaction chromatography are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. CELLULOSE EXTRACTION FROM PALM KERNEL CAKE USING LIQUID PHASE OXIDATION

    Directory of Open Access Journals (Sweden)

    FARM YAN YAN

    2009-03-01

    Full Text Available Cellulose is widely used in many aspect and industries such as food industry, pharmaceutical, paint, polymers, and many more. Due to the increasing demand in the market, studies and work to produce cellulose are still rapidly developing. In this work, liquid phase oxidation was used to extract cellulose from palm kernel cake to separate hemicellulose, cellulose and lignin. The method is basically a two-step process. Palm kernel cake was pretreated in hot water at 180°C and followed by liquid oxidation process with 30% H2O2 at 60°C at atmospheric pressure. The process parameters are hot water treatment time, ratio of palm kernel cake to H2O2, liquid oxidation reaction temperature and time. Analysis of the process parameters on production cellulose from palm kernel cake was performed by using Response Surface Methodology. The recovered cellulose was further characterized by Fourier Transform Infrared (FTIR. Through the hot water treatment, hemicellulose in the palm kernel cake was successfully recovered as saccharides and thus leaving lignin and cellulose. Lignin was converted to water soluble compounds in liquid oxidation step which contains small molecular weight fatty acid as HCOOH and CH3COOH and almost pure cellulose was recovered.

  2. Combined liquid and solid-phase extraction improves quantification of brain estrogen content

    Directory of Open Access Journals (Sweden)

    Andrew eChao

    2011-09-01

    Full Text Available Accuracy in quantifying brain-derived steroid hormones (‘neurosteroids’ has become increasingly important for understanding the modulation of neuronal activity, development, and physiology. Relative to other neuroactive compounds and classical neurotransmitters, steroids pose particular challenges with regard to isolation and analysis, owing to their lipid solubility. Consequently, anatomical studies of the distribution of neurosteroids have relied primarily on the expression of neurosteroid synthesis enzymes. To evaluate the distribution of synthesis enzymes vis-à-vis the actual steroids themselves, traditional steroid quantification assays, including radioimmunoassays (RIA, have successfully employed liquid extraction methods (e.g., ether, dichloromethane or methanol to isolate steroids from microdissected brain tissue. Due to their sensitivity, safety and reliability, the use of commercial enzyme immunoassays (EIA for laboratory quantification of steroids in plasma and brain has become increasingly widespread. However, EIAs rely on enzymatic reactions in vitro, making them sensitive to interfering substances in brain tissue and thus producing unreliable results. Here, we evaluate the effectiveness of a protocol for combined, two-stage liquid/solid phase extraction as compared to conventional liquid extraction alone for the isolation of estradiol (E2 from brain tissue. We employ the songbird model system, in which brain steroid production is pronounced and linked to neural mechanisms of learning and plasticity. This study outlines a combined liquid-solid phase extraction protocol that improves the performance of a commercial EIA for the quantification of brain E2 content. We demonstrate the effectiveness of our optimized method for evaluating the region specificity of brain E2 content, compare these results to established anatomy of the estrogen synthesis enzyme and estrogen receptor, and discuss the nature of potential EIA interfering

  3. Liquid Phases in SU(3) Chiral Perturbation Theory: Drops of Strange Chiral Nucleon Liquid & Ordinary Chiral Heavy Nuclear Liquid

    CERN Document Server

    Lynn, Bryan W.

    2010-01-01

    Chiral SU(3) Perturbation Theory (SU3XPT) identifies hadrons as the building blocks of strongly interacting matter at low densities and temperatures. We show that it admits two co-existing chiral nucleon liquid phases at zero external pressure with well-defined surfaces: 1) ordinary microscopic chiral heavy nuclear liquid drops (XNL) and 2) a new Strange Chiral Nucleon Liquid (SXNL) phase with both microscopic and macroscopic drop sizes. Liquid drops of both XNL and SXNL are simultaneously solutions to the SU3XPT semi-classical equations of motion and obey all relevant CVC and PCAC equations. Axial-vector currents are conserved inside macroscopic drops of SXNL, a new form of baryonic matter with zero electric charge density, which is by nature "dark". The numerical values of all SU3XPT coefficients are used to fit current scattering experiments and ordinary XNL drops (identified with the ground state of ordinary even-even spin-zero spherical closed-shell nuclei). SXNL then also emerges (i.e. without new adjus...

  4. Drug Release and Skin Permeation from Lipid Liquid Crystalline Phases

    Science.gov (United States)

    Costa-Balogh, F. O.; Sparr, E.; Sousa, J. J. S.; Pais, A. A. C. C.

    We have studied drug release and skin permeation from several different liquid crystalline lipid formulations that may be used to control the respective release rates. We have studied the release and permeation through human skin of a water-soluble and amphiphilic drug, propranolol hydrochloride, from several formulations prepared with monoolein and phytantriol as permeation enhancers and controlled release excipients. Diolein and cineol were added to selected formulations. We observed that viscosity decreases with drug load, wich is compatible with the occurrence of phase changes. Diolein stabilizes the bicontinuous cubic phases leading to an increase in viscosity and sustained release of the drug. The slowest release was found for the cubic phases with higher viscosity. Studies on skin permeation showed that these latter formulations also presented lower permeability than the less viscous monoolein lamellar phases. Formulations containing cineol originated higher permeability with higher enhancement ratios. Thus, the various formulations are adapted to different circumstances and delivery routes. While a slow release is usually desired for drug sustained delivery, the transdermal route may require a faster release. Lamellar phases, which are less viscous, are more adapted to transdermal applications. Thus, systems involving lamellar phases of monoolein and cineol are good candidates to be used as skin permeation enhancers for propranolol hydrochloride.

  5. Modified phase-field-crystal model for solid-liquid phase transitions.

    Science.gov (United States)

    Guo, Can; Wang, Jincheng; Wang, Zhijun; Li, Junjie; Guo, Yaolin; Tang, Sai

    2015-07-01

    A modified phase-field-crystal (PFC) model is proposed to describe solid-liquid phase transitions by reconstructing the correlation function. The effects of fitting parameters of our modified PFC model on the bcc-liquid phase diagram, numerical stability, and solid-liquid interface properties during planar interface growth are examined carefully. The results indicate that the increase of the correlation function peak width at k=k(m) will enhance the stability of the ordered phase, while the increase of peak height at k=0 will narrow the two-phase coexistence region. The third-order term in the free-energy function and the short wave-length of the correlation function have significant influences on the numerical stability of the PFC model. During planar interface growth, the increase of peak width at k=k(m) will decrease the interface width and the velocity coefficient C, but increase the anisotropy of C and the interface free energy. Finally, the feasibility of the modified phase-field-crystal model is demonstrated with a numerical example of three-dimensional dendritic growth of a body-centered-cubic structure.

  6. Highly tilted liquid crystalline materials possessing a direct phase transition from antiferroelectric to isotropic phase

    Energy Technology Data Exchange (ETDEWEB)

    Milewska, K.; Drzewiński, W. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Czerwiński, M., E-mail: mczerwinski@wat.edu.pl [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Dąbrowski, R. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Piecek, W. [Institute of Applied Physics, Military University of Technology, 00-908 Warsaw (Poland)

    2016-03-01

    Pure compounds and multicomponent mixtures with a broad temperature range of high tilted liquid crystalline antiferroelectric phase and a direct phase transition from antiferroelectric to isotropic phase, were obtained. X-ray diffraction analysis confirms these kinds of materials form a high tilted anticlinic phase, with a fixed layer spacing and very weak dependency upon temperature, after the transition from the isotropic phase. Due to this, not only pure orthoconic antiferroelectric liquid crystals but also those with a moderate tilt should generate a good dark state. Furthermore, due to the increased potential for forming anticlinic forces, such materials could minimize a commonly observed asymmetry of a rise and fall switching times at a surface stabilized geometry. - Highlights: • The new class of liquid crystalline materials with the direct SmC{sub A}*. • Iso phase transition were obtained. • Materials possess the layer spacing fixed and very weak dependent upon temperature. • Smectic layers without shrinkage are observed. • A good dark state can be generate in SSAFLC.

  7. Evidence of Microporous Carbon Nanosheets Showing Fast Kinetics in both Gas Phase and Liquid Phase Environments.

    Science.gov (United States)

    Jin, Zhen-Yu; Xu, Yuan-Yuan; Sun, Qiang; Lu, An-Hui

    2015-10-01

    Despite the great advantages of microporous carbons for applications in gas phase separation, liquid phase enrichment, and energy storage devices, direct experiment data and theoretical calculations on the relevance of properties and structures are quite limited. Herein, two model carbon materials are designed and synthesized, i.e., microporous carbon nanosheets (MCN) and microporous carbon spheres (MCS). They both have nearly same composition, surface chemistry, and specific surface area, known morphology, but distinguishable diffusion paths. Based on these two types of materials, a reliable relationship between the morphology with different diffusion paths and adsorption kinetics in both gas phase and liquid phase environments is established. When used for CO2 capture, MCN shows a high saturated CO2 capacity of 8.52 μmol m(-2) and 18.4 mmol cm(-3) at 273 K and ambient pressure, and its calculated first-order rate constant is ≈7.4 times higher than that of MCS. Moreover, MCN shows a quick and high uptake of Cr (VI) and a higher-rate performance for supercapacitors than MCS does. These results strongly confirm that MCN exhibits improved kinetics in gas phase separation, liquid phase enrichment, and energy storage devices due to its shorter diffusion paths and larger exposed geometrical area resulting from the nanosheet structure. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

    KAUST Repository

    Hellmann, Christoph

    2014-12-17

    © 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

  9. Solvatochromic characterization of the liquid phase in liquid-supercritical CO{sub 2} mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, S.P.; Lemert, R.M. [Univ. of Toledo, OH (United States). Chemical Engineering Dept.

    1996-07-01

    The solvatochromic dye phenol blue (N,N-dimethylindoaniline) is used to characterize the solvent strength (polarity) of the saturated liquid phase in a series of solvent-carbon dioxide binary mixtures. Data were obtained at 35 and 55 C and at pressures up to {approximately}70 bar. Five solvents were investigated--acetone, cyclohexane, methanol, THF, and toluene. The polarity of the liquid phase decreases significantly with increasing pressure due to the increasing carbon dioxide content of this phase at equilibrium. For example, the polarity of acetone saturated with carbon dioxide at 35 C and {approximately}60 bar is equivalent to the polarity of pure cyclohexane at ambient pressure. The local environment about the dye is significantly richer in the polar liquid component than the bulk composition would indicate. The degree of enrichment reflects concentration effects at low pressure, and both concentration and pressure effects at high pressure where the mixtures are highly compressible. The NRTL model of Renon and Prausnitz is able to predict these local compositions with reasonable accuracy except at CO{sub 2}-rich conditions where compressibility effects are important.

  10. Transient liquid-phase bonding using coated metal powders

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, W.D.; Eagar, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

    1997-04-01

    Powder particles coated with a small amount of melting point depressant (MPD) reveal different sintering behavior in comparison to an uncoated powder mixture of the same composition. Interlayers consisting of the coated powder particles were used in the transient liquid-phase (TLP) bonding process. The coating material and the thickness of the deposit are important parameters that influence shrinkage. The amount of MPD was controlled such that the volume fraction of the liquid was very small but existed at all contacts, thus improving densification of the interlayer. Ni-20Cr and 304L stainless steel powders coated with Ni-10P were applied to join 304 stainless steels. Fully dense joints with mechanical properties comparable to those of the base metals were obtained with Ni-20Cr powder interlayers, whereas joints with 304L stainless steel powder interlayers showed inferior mechanical properties due to residual porosity in the joints.

  11. Sample Preparation and Liquid Chromatography Mass Spectrometry Analysis of Alkylphenolic Compounds and Steroid Sex Hormones in Sediments

    Directory of Open Access Journals (Sweden)

    Mira Petrovia

    2002-01-01

    Full Text Available A new methodology, based on the use of accelerated solvent extraction (ASE and highly selective cleanup using restricted access material (RAM on-line coupled with liquid chromatography–mass spectrometry (LC–MS, is presented for the simultaneous and unequivocal determination of alkylphenol ethoxylates (APEOs, their degradation products and halogenated derivatives, and steroid sex hormones in sediment samples. Using the integrated RAM–LC–MS system, the simultaneous determination of alkylphenolic compounds and sex hormones was achieved, yielding recoveries higher than 60% and producing low MS background noise.

  12. Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

    Directory of Open Access Journals (Sweden)

    J.M. Ilnytskyi

    2010-01-01

    Full Text Available A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr is presented. It allows, for the first time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008]. Coarse-grained (CG molecular dynamics (MD simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning field of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like, leading to formation of a monodomain smectic A (SmA or a columnar (Col phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.

  13. Extraction of proteins with ionic liquid aqueous two-phase system based on guanidine ionic liquid.

    Science.gov (United States)

    Zeng, Qun; Wang, Yuzhi; Li, Na; Huang, Xiu; Ding, Xueqin; Lin, Xiao; Huang, Songyun; Liu, Xiaojie

    2013-11-15

    Eight kinds of green ionic liquids were synthesized, and an ionic liquid aqueous two-phase system (ILATPS) based on 1,1,3,3-tetramethylguandine acrylate (TMGA) guanidine ionic liquid was first time studied for the extraction of proteins. Single factor experiments proved that the extraction efficiency of bovine serum albumin (BSA) was influenced by the mass of IL, K2HPO4 and BSA, also related to the separation time and temperature. The optimum conditions were determined through orthogonal experiment by the five factors described above. The results showed that under the optimum conditions, the extraction efficiency could reach up to 99.6243%. The relative standard deviations (RSD) of extraction efficiencies in precision experiment, repeatability experiment and stability experiment were 0.8156% (n=5), 1.6173% (n=5) and 1.6292% (n=5), respectively. UV-vis and FT-IR spectra confirmed that there were no chemical interactions between BSA and ionic liquid in the extraction process, and the conformation of the protein was not changed after extraction. The conductivity, DLS and TEM were combined to investigate the microstructure of the top phase and the possible mechanism for the extraction. The results showed that hydrophobic interaction, hydrogen bonding interaction and the salt out effect played important roles in the transferring process, and the aggregation and embrace phenomenon was the main driving force for the separation. All these results proved that guanidine ionic liquid-based ATPSs have the potential to offer new possibility in the extraction of proteins. © 2013 Elsevier B.V. All rights reserved.

  14. Vapors-liquid phase separator. [infrared telescope heat sink

    Science.gov (United States)

    Frederking, T. H. K.; Brown, G. S.; Chuang, C.; Kamioka, Y.; Kim, Y. I.; Lee, J. M.; Yuan, S. W. K.

    1980-01-01

    The use of porous plugs, mostly with in the form of passive devices with constant area were considered as vapor-liquid phase separators for helium 2 storage vessels under reduced gravity. The incorporation of components with variable cross sectional area as a method of flow rate modification was also investigated. A particular device which uses a shutter-type system for area variation was designed and constructed. This system successfully permitted flor rate changes of up to plus or minus 60% from its mean value.

  15. Terahertz saturable absorbers from liquid phase exfoliation of graphite

    OpenAIRE

    Bianchi, Vezio; Carey, Tian; Viti, Leonardo; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles; Tredicucci, Alessandro; Yoon, Duhee; Karagiannidis, Panagiotis; Lombardi, Lucia; Tomarchio, Flavia; Ferrari, Andrea C.; Torrisi, Felice; Vitiello, Miriam S.

    2017-01-01

    Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ∼80%, almost one order of magnitude larger than that reported to date at TH...

  16. Environmental information volume: Liquid Phase Methanol (LPMEOH{trademark}) project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The purpose of this project is to demonstrate the commercial viability of the Liquid Phase Methanol Process using coal-derived synthesis gas, a mixture of hydrogen and carbon monoxide. This report describes the proposed actions, alternative to the proposed action, the existing environment at the coal gasification plant at Kingsport, Tennessee, environmental impacts, regulatory requirements, offsite fuel testing, and DME addition to methanol production. Appendices include the air permit application, solid waste permits, water permit, existing air permits, agency correspondence, and Eastman and Air Products literature.

  17. Liquid-Phase Processing of Barium Titanate Thin Films

    Science.gov (United States)

    Harris, David Thomas

    Processing of thin films introduces strict limits on the thermal budget due to substrate stability and thermal expansion mismatch stresses. Barium titanate serves as a model system for the difficulty in producing high quality thin films because of sensitivity to stress, scale, and crystal quality. Thermal budget restriction leads to reduced crystal quality, density, and grain growth, depressing ferroelectric and nonlinear dielectric properties. Processing of barium titanate is typically performed at temperatures hundreds of degrees above compatibility with metalized substrates. In particular integration with silicon and other low thermal expansion substrates is desirable for reductions in costs and wider availability of technologies. In bulk metal and ceramic systems, sintering behavior has been encouraged by the addition of a liquid forming second phase, improving kinetics and promoting densification and grain growth at lower temperatures. This approach is also widespread in the multilayer ceramic capacitor industry. However only limited exploration of flux processing with refractory thin films has been performed despite offering improved dielectric properties for barium titanate films at lower temperatures. This dissertation explores physical vapor deposition of barium titanate thin films with addition of liquid forming fluxes. Flux systems studied include BaO-B2O3, Bi2O3-BaB2O 4, BaO-V2O5, CuO-BaO-B2O3, and BaO-B2O3 modified by Al, Si, V, and Li. Additions of BaO-B2O3 leads to densification and an increase in average grain size from 50 nm to over 300 nm after annealing at 900 °C. The ability to tune permittivity of the material improved from 20% to 70%. Development of high quality films enables engineering of ferroelectric phase stability using residual thermal expansion mismatch in polycrystalline films. The observed shifts to TC match thermodynamic calculations, expected strain from the thermal expansion coefficients, as well as x-ray diffract measurements

  18. Simultaneous determination of selected hormones, endocrine disruptor compounds, and pesticides in water medium at trace levels by GC-MS after dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Chormey, Dotse Selali; Büyükpınar, Çağdaş; Turak, Fatma; Komesli, Okan Tarık; Bakırdere, Sezgin

    2017-06-01

    The need to enhance food safety has led to major advancements in pesticide productions, and though many benefits have been gained, environmental contamination has also risen from these chemicals that tend to persist in the environment. Some pesticides, together with other chemicals commonly called endocrine disruptor compounds, block the receptor sites of hormones or mimic displaced hormones, leading to imbalanced hormonal levels that result in health disorders and diseases. These chemicals occur at trace levels and are not directly detected by conventional analytical methods. A dispersive liquid-liquid microextraction method was therefore developed for preconcentration of 12 analytes including hormones, endocrine disruptor compounds, and pesticides, to be analyzed by gas chromatography mass spectrometry. This was achieved by optimizing parameters such as extractor solvent type and amount, dispersive solvent type and amount, pH, and salt effect that affect extraction output. The limits of detection and quantification of the developed method were between 0.09 and 3.36 and 0.31 and 11.19 ng mL-1, respectively. The calibration plots of the analytes also showed good linearity and low percent relative standard deviations. Recovery studies were performed for tap water and wastewater samples, and the percent recoveries recorded were between 84 and 109%.

  19. Liquid-liquid phase separation in aerosol particles: Imaging at the Nanometer Scale

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Rachel; Wang, Bingbing; Kelly, Stephen T.; Lundt, Nils; You, Yuan; Bertram, Allan K.; Leone, Stephen R.; Laskin, Alexander; Gilles, Mary K.

    2015-04-21

    Atmospheric aerosols can undergo phase transitions including liquid-liquid phase separation (LLPS) while responding to changes in the ambient relative humidity (RH). Here, we report results of chemical imaging experiments using environmental scanning electron microscopy (ESEM) and scanning transmission x-ray microscopy (STXM) to investigate the LLPS of micron sized particles undergoing a full hydration-dehydration cycle. Internally mixed particles composed of ammonium sulfate (AS) and either: limonene secondary organic carbon (LSOC), a, 4-dihydroxy-3-methoxybenzeneaceticacid (HMMA), or polyethylene glycol (PEG-400) were studied. Events of LLPS with apparent core-shell particle morphology were observed for all samples with both techniques. Chemical imaging with STXM showed that both LSOC/AS and HMMA/AS particles were never homogeneously mixed for all measured RH’s above the deliquescence point and that the majority of the organic component was located in the shell. The shell composition was estimated as 65:35 organic: inorganic in LSOC/AS and as 50:50 organic: inorganic for HMMA/AS. PEG-400/AS particles showed fully homogeneous mixtures at high RH and phase separated below 89-92% RH with an estimated 50:50% organic to inorganic mix in the shell. These two chemical imaging techniques are well suited for in-situ analysis of the hygroscopic behavior, phase separation, and surface composition of collected ambient aerosol particles.

  20. Growth Kinetics of Intracellular RNA/Protein Droplets: Signature of a Liquid-Liquid Phase Transition?

    Science.gov (United States)

    Berry, Joel; Weber, Stephanie C.; Vaidya, Nilesh; Zhu, Lian; Haataja, Mikko; Brangwynne, Clifford P.

    2015-03-01

    Nonmembrane-bound organelles are functional, dynamic assemblies of RNA and/or protein that can self-assemble and disassemble within the cytoplasm or nucleoplasm. The possibility that underlying intracellular phase transitions may drive and mediate the morphological evolution of some membrane-less organelles has been supported by several recent studies. In this talk, results from a collaborative experimental-theoretical study of the growth and dissolution kinetics of nucleoli and extranucleolar droplets (ENDs) in C. elegans embryos will be presented. We have employed Flory-Huggins solution theory, reaction-diffusion kinetics, and quantitative statistical dynamic scaling analysis to characterize the specific growth mechanisms at work. Our findings indicate that both in vivo and in vitro droplet scaling and growth kinetics are consistent with those resulting from an equilibrium liquid-liquid phase transition mediated by passive nonequilibrium growth mechanisms - simultaneous Brownian coalescence and Ostwald ripening. This supports a view in which cells can employ phase transitions to drive structural organization, while utilizing active processes, such as local transcriptional activity, to fine tune the kinetics of these phase transitions in response to given conditions.

  1. Tube Radial Distribution Flow Separation in a Microchannel Using an Ionic Liquid Aqueous Two-Phase System Based on Phase Separation Multi-Phase Flow.

    Science.gov (United States)

    Nagatani, Kosuke; Shihata, Yoshinori; Matsushita, Takahiro; Tsukagoshi, Kazuhiko

    2016-01-01

    Ionic liquid aqueous two-phase systems were delivered into a capillary tube to achieve tube radial distribution flow (TRDF) or annular flow in a microspace. The phase diagram, viscosity of the phases, and TRDF image of the 1-butyl-3-methylimidazolium chloride and NaOH system were examined. The TRDF was formed with inner ionic liquid-rich and outer ionic liquid-poor phases in the capillary tube. The phase configuration was explained using the viscous dissipation principle. We also examined the distribution of rhodamine B in a three-branched microchannel on a microchip with ionic liquid aqueous two-phase systems for the first time.

  2. Liquid-gas Coexistence Phase in Nuclear Matter

    Science.gov (United States)

    Salcedo, Alan; Lopez, Jorge; Terrazas, Sergio; Gaytan, Adrian

    2017-09-01

    Nuclear matter at low temperatures (T CMD). In this study, we present data obtained from CMD simulations and a method to determine a 3-dimensional phase diagram using these results, interpolation techniques, and Maxwell constructions. We performed more than 300 simulations of nuclear matter for settings of 2000 nucleons with isospin content X (Z/A) = 0.3, 0.35, 0.4, 0.45, 0.5 at temperatures of T = 1-5 MeV and T = 10-15 MeV, with densities between 0.02 fm-3 and 0.18 fm-3. Our results of pressure per nucleon for each system were stored and analyzed to construct a phase diagram. From this study, we aim to extract the boundaries and shape of the liquid-gas coexistence region for neutron-rich nuclear matter, thus determining its intrinsic physical conditions.

  3. Influences of misfit strains on liquid phase heteroepitaxial growth

    Science.gov (United States)

    Lu, Yanli; Peng, Yingying; Yu, Genggeng; Chen, Zheng

    2017-10-01

    Influences of misfit strains with different signs on liquid phase heteroepitaxial growth are studied by binary phase field crystal model. It is amazing to find that double islands are formed because of lateral and vertical separation. The morphological evolution of epitaxial layer depends on signs of misfit strains. The maximum atomic layer thickness of double islands under negative misfit strain is larger than that of under positive misfit strain at the same evolutional time, and size differences between light and dark islands is much smaller under negative misfit strain than that of under positive misfit strain. In addition, concentration field and density field approximately have similar variational law along x direction under the same misfit strain but show opposite variational trend under misfit strains with different signs. Generally, free energy of epitaxial growth systems keeps similar variational trend under misfit strains with different signs.

  4. Espresso coffee foam delays cooling of the liquid phase.

    Science.gov (United States)

    Arii, Yasuhiro; Nishizawa, Kaho

    2017-04-01

    Espresso coffee foam, called crema, is known to be a marker of the quality of espresso coffee extraction. However, the role of foam in coffee temperature has not been quantitatively clarified. In this study, we used an automatic machine for espresso coffee extraction. We evaluated whether the foam prepared using the machine was suitable for foam analysis. After extraction, the percentage and consistency of the foam were measured using various techniques, and changes in the foam volume were tracked over time. Our extraction method, therefore, allowed consistent preparation of high-quality foam. We also quantitatively determined that the foam phase slowed cooling of the liquid phase after extraction. High-quality foam plays an important role in delaying the cooling of espresso coffee.

  5. Volume phase transitions of cholesteric liquid crystalline gels

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp [Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502 (Japan)

    2015-05-07

    We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.

  6. Hypothalamic-pituitary-gonadal axis hormones and cortisol in both menstrual phases of women with chronic fatigue syndrome and effect of depressive mood on these hormones

    Directory of Open Access Journals (Sweden)

    Nas Kemal

    2004-12-01

    Full Text Available Abstract Background Chronic fatigue syndrome (CFS is a disease which defined as medically unexplained, disabling fatigue of 6 months or more duration and often accompanied by several of a long list of physical complaints. We aimed to investigate abnormalities of hypothalamic-pituitary-gonadal (HPG axis hormones and cortisol concentrations in premenopausal women with CFS and find out effects of depression rate on these hormones. Methods We examined follicle stimulating hormone (FSH, luteinizing hormone (LH, estradiol, progesterone and cortisol concentrations in 43 premenopausal women (mean age: 32.86 ± 7.11 with CFS and compared matched 35 healthy controls (mean age: 31.14 ± 6.19. Patients were divided according to menstrual cycle phases (follicular and luteal and compared with matched phase controls. Depression rate was assessed by Beck Depression Inventory (BDI, and patients with high BDI scores were compared to patients with low BDI scores. Results There were no significant differences in FSH, LH, estradiol and progesterone levels in both of menstrual phases of patients versus controls. Cortisol levels were significantly lower in patients compared to controls. There were no significant differences in all hormone levels in patients with high depression scores versus patients with low depression scores. Conclusion In spite of high depression rate, low cortisol concentration and normal HPG axis hormones of both menstrual phases are detected in premenopausal women with CFS. There is no differentiation between patients with high and low depression rate in all hormone levels. Depression condition of CFS may be different from classical depression and evaluation of HPG and HPA axis should be performed for understanding of pathophysiology of CFS and planning of treatment.

  7. Stabilizing blue phase liquid crystals with linearly polarized UV light

    Science.gov (United States)

    Xu, Daming; Yuan, Jiamin; Schadt, Martin; Yan, Jing; Wu, Shin-Tson

    2015-03-01

    Polymer-stabilized blue-phase liquid crystal (PS-BPLC) has become an increasingly important technology trend for information display and photonic applications. BPLC exhibits several attractive features, such as reasonably wide temperature range, submillisecond gray-to-gray response time, no need for alignment layer, optically isotropic voltageoff state, and large cell gap tolerance when an in-plane switching (IPS) cell is employed. However, some bottlenecks such as high operation voltage, relatively low transmittance, and noticeable hysteresis and prolonged response time at high field region for IPS mode, still remain to be overcome before widespread application of BPLC can be realized. To reduce operation voltage, both new BPLC materials and new device structures have been investigated. In this paper, we demonstrate the stabilization a photopolymer-embedded blue phase liquid crystal precursor using a linearly polarized UV light for first time. When the UV polarization axis is perpendicular to the stripe electrodes of an IPS cell, anisotropic polymer networks are formed through the linear photo-polymerization process and the electrostriction effect is suppressed. As a result, the measured hysteresis is dramatically reduced from 6.95% to 0.36% and the response time shortened by ~2X compared to unpolarized UV exposure. To induce larger anisotropy in polymer networks for mitigating the electrostriction effect, high-intensity linearly polarized UV exposure is preferred. It is foreseeable this method will guide future BPLC device and material development as well as manufacturing process. The dawn of BPLCD is near.

  8. Comparing two tetraalkylammonium ionic liquids. II. Phase transitions

    Science.gov (United States)

    Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C.; Ferreira, Fabio F.; Costa, Fanny N.; Giles, Carlos

    2016-06-01

    Phase transitions of the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N1114][NTf2], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N1444][NTf2], were investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD) measurements, and Raman spectroscopy. XRD and Raman spectra were obtained as a function of temperature at atmospheric pressure, and also under high pressure at room temperature using a diamond anvil cell (DAC). [N1444][NTf2] experiences glass transition at low temperature, whereas [N1114][NTf2] crystallizes or not depending on the cooling rate. Both the ionic liquids exhibit glass transition under high pressure. XRD and low-frequency Raman spectra provide a consistent physical picture of structural ordering-disordering accompanying the thermal events of crystallization, glass transition, cold crystallization, pre-melting, and melting. Raman spectra in the high-frequency range of some specific cation and anion normal modes reveal conformational changes of the molecular structures along phase transitions.

  9. Dynamic headspace time-extended helix liquid-phase microextraction.

    Science.gov (United States)

    Huang, Shih-Pin; Chen, Pai-Shan; Huang, Shang-Da

    2009-05-15

    Liquid-phase microextraction (LPME) has been proved to be a fast, inexpensive and effective sample pre-treatment technique for the analyses of pesticides and many other compounds. In this investigation, a new headspace microextraction technique, dynamic headspace time-extended helix liquid-phase microextraction (DHS-TEH-LPME), is presented. In this work, use of a solvent cooling system, permits the temperature of the extraction solvent to be lowered. Lowering the temperature of the extraction solvent not only reduces solvent loss but also extends the feasible extraction time, thereby improving extraction efficiency. Use of a larger volume of the solvent not only extends the feasible extraction time but also, after extraction, leaves a larger volume to be directly injected into the gas chromatography (GC) to increase extraction efficiency and instrument signal. The DHS-TEH-LPME technique was used to extract six organochlorine pesticides (OCPs) from 110ml water samples that had been spiked with the analytes at ng/l levels, and stirred for 60min. The proposed method attained enrichments up to 2121 fold. The effects of extraction solvent identity, sample agitation, extraction time, extraction temperature, and salt concentration on extraction performance were also investigated. The method detection limits (MDLs) varied from 0.2 to 25ng/l. The calibration curves were linear for at least 2 orders of magnitude with R(2)>==0.996. Relative recoveries in river water were more than 86%.

  10. Comparing two tetraalkylammonium ionic liquids. II. Phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C., E-mail: mccribei@iq.usp.br [Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP (Brazil); Ferreira, Fabio F.; Costa, Fanny N. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP (Brazil); Giles, Carlos [Depto. de Física da Matéria Condensada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP (Brazil)

    2016-06-14

    Phase transitions of the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1114}][NTf{sub 2}], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1444}][NTf{sub 2}], were investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD) measurements, and Raman spectroscopy. XRD and Raman spectra were obtained as a function of temperature at atmospheric pressure, and also under high pressure at room temperature using a diamond anvil cell (DAC). [N{sub 1444}][NTf{sub 2}] experiences glass transition at low temperature, whereas [N{sub 1114}][NTf{sub 2}] crystallizes or not depending on the cooling rate. Both the ionic liquids exhibit glass transition under high pressure. XRD and low-frequency Raman spectra provide a consistent physical picture of structural ordering-disordering accompanying the thermal events of crystallization, glass transition, cold crystallization, pre-melting, and melting. Raman spectra in the high-frequency range of some specific cation and anion normal modes reveal conformational changes of the molecular structures along phase transitions.

  11. Expression of two glycoprotein hormone receptors in larval, parasitic phase, and adult sea lampreys.

    Science.gov (United States)

    Hausken, Krist N; Marquis, Timothy J; Sower, Stacia A

    2017-11-21

    All jawed vertebrates have three canonical glycoprotein hormones (GpHs: luteinizing hormone, LH; follicle stimulating hormone, FSH; and thyroid stimulating hormone, TSH) with three corresponding GpH receptors (GpH-Rs: LH-R, FSH-R, and TSH-R). In contrast, we propose that the jawless vertebrate, the sea lamprey (Petromyzon marinus), only has two pituitary glycoprotein hormones, lamprey (l)GpH and l-thyrostimulin, and two functional glycoprotein receptors, lGpH-R I and II. It is not known at this time whether there is a specific receptor for lGpH and l-thyrostimulin, or if both GpHs can differentially activate the lGpH-Rs. In this report, we determined the RNA expression of lGpH-R I and II in the gonads and thyroids of larval, parasitic phase, and adult lampreys. A highly sensitive dual-label fluorescent in situ hybridization technique (RNAScope™) showed lGpH-R I expression in the ovaries of larval lamprey, and co-localization and co-expression of lGpH-R I and II in the ovaries of parasitic phase and adult lampreys. Both receptors were also highly co-localized and co-expressed in the endostyle of larval lamprey and thyroid follicles of parasitic and adult lampreys. In addition, we performed in vivo studies to determine the actions of lamprey gonadotropin releasing hormones (lGnRHs) on lGpH-R I and II expression by real time PCR, and determined plasma concentrations of estradiol and thyroxine. Administration of lGnRH-III significantly (p ≤ 0.01) increased lGpHR II expression in the thyroid follicles of adult female lampreys but did not cause a significant increase in RNA expression of lGpH-R I and II in ovaries. Concomitantly, there was a significant increase (p ≤ 0.01) of plasma estradiol without any significant changes of plasma thyroxine concentrations in response to treatment to lGnRH-I, -II, or -III. In summary, our results provide supporting evidence that the lamprey pituitary glycoprotein hormones may differentially activate the lamprey GpH-Rs in

  12. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    Science.gov (United States)

    Qazi, H. I. A.; Nie, Qiu-Yue; Li, He-Ping; Zhang, Xiao-Fei; Bao, Cheng-Yu

    2015-12-01

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A-X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  13. Standard Specification for Sampling Single-Phase Geothermal Liquid or Steam for Purposes of Chemical Analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1983-01-01

    1.1 This specification covers the basic requirements for equipment to be used for the collection of uncontaminated and representative samples from single-phase geothermal liquid or steam. Geopressured liquids are included. See Fig 1.

  14. A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

    Science.gov (United States)

    Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

    2017-09-01

    Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

  15. Early follicular phase hormone levels in relation to patterns of alcohol, tobacco, and coffee use.

    Science.gov (United States)

    Lucero, J; Harlow, B L; Barbieri, R L; Sluss, P; Cramer, D W

    2001-10-01

    To examine the effects of alcohol, caffeine, and tobacco use on early follicular phase FSH, LH, E2, and sex hormone-binding globulin (SHBG). Cross-sectional study. Academic medical center. Four hundred ninety-eight women selected from the general population, ages 36-45, who were not currently pregnant, breast feeding, or using exogenous hormones. A general questionnaire assessing demography, anthropometry, and smoking habits and a standardized dietary questionnaire assessing food and beverage frequencies, including sources of alcohol and caffeine. FSH, LH, E2, and SHBG levels measured during the early follicular phase of the menstrual cycle. Significant associations observed in a univariate analysis included age > or =40 and current smoking associated with higher FSH; higher body mass index (BMI) associated with lower SHBG levels; and daily alcohol use, cholesterol consumption greater than the median, and coffee use >1 cup/d associated with higher E2 levels. In a multivariate model, total caffeine use was significantly associated with E2 levels after adjustment for age, BMI, total calories, current smoking, alcohol, cholesterol consumption, and day of sampling. Early follicular phase E2 increased from 28.2 pg/mL for women consuming or =500 mg of caffeine per day, about a 70% increase. Coffee consumption and total caffeine use may increase early follicular phase E2 levels independent of related habits of alcohol or tobacco use.

  16. Continuous fixed-bed gas-phase hydroformylation using supported ionic liquid-phase (SILP) Rh catalysts

    DEFF Research Database (Denmark)

    Riisager, Anders; Wasserscheid, Peter; Van Hal, R.

    2003-01-01

    Continuous flow gas-phase hydroformylation of propene was performed using novel supported ionic liquid-phase (SILP) catalysts containing immobilized Rh complexes of the biphosphine ligand sulfoxantphos in the ionic liquids 1-n-butyl-3-methylimidazolium hexafluorophosphate and halogen-free 1-n...

  17. Cephalic phase secretion of insulin and other enteropancreatic hormones in humans

    DEFF Research Database (Denmark)

    Veedfald, Simon; Plamboeck, Astrid; Deacon, Carolyn F

    2016-01-01

    Enteropancreatic hormone secretion is thought to include a cephalic phase, but the evidence in humans is ambiguous. We studied vagally induced gut hormone responses with and without muscarinic blockade in 10 glucose-clamped healthy men (age: 24.5 ± 0.6 yr, means ± SE; body mass index: 24.0 ± 0.5 kg...... and abolished the MSF response. Neither insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP), nor glucagon-like peptide-1 (GLP-1) levels changed in response to MSF or atropine. Glucagon and ghrelin levels were markedly attenuated by atropine prior to and during the clamp: at t = 105 min...... and 3.7 ± 21 pg/ml (means ± SE), P insulin, glucagon, GLP-1, GIP, and ghrelin....

  18. Continuous gas-phase hydroformylation of 1-butene using supported ionic liquid phase (SILP) catalysts

    DEFF Research Database (Denmark)

    Haumann, Marco; Dentler, Katharina; Joni, Joni

    2007-01-01

    The concept of supported ionic liquid phase (SILP) catalysis has been extended to 1-butene hydroformylation. A rhodium-sulfoxantphos complex was dissolved in [BMIM][n-C8H17OSO3] and this solution was highly dispersed on silica. Continuous gas-phase experiments in a fixed-bed reactor revealed...... another excellent hint for truly homogeneous catalysis in the SILP system. Compared to former studies using propene, the SILP system showed significantly higher activity and selectivity with 1-butene as feedstock. These findings could be elucidated by solubility measurements using a magnetic microbalance....

  19. Structure analysis of turbulent liquid phase by POD and LSE techniques

    Energy Technology Data Exchange (ETDEWEB)

    Munir, S., E-mail: shahzad-munir@comsats.edu.pk; Muthuvalu, M. S.; Siddiqui, M. I. [Department of Fundamental and Applied Science, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia); Heikal, M. R., E-mail: morgan.heikal@petronas.com.my; Aziz, A. Rashid A., E-mail: morgan.heikal@petronas.com.my [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)

    2014-10-24

    In this paper, vortical structures and turbulence characteristics of liquid phase in both single liquid phase and two-phase slug flow in pipes were studied. Two dimensional velocity vector fields of liquid phase were obtained by Particle image velocimetry (PIV). Two cases were considered one single phase liquid flow at 80 l/m and second slug flow by introducing gas at 60 l/m while keeping liquid flow rate same. Proper orthogonal decomposition (POD) and Linear stochastic estimation techniques were used for the extraction of coherent structures and analysis of turbulence in liquid phase for both cases. POD has successfully revealed large energy containing structures. The time dependent POD spatial mode coefficients oscillate with high frequency for high mode numbers. The energy distribution of spatial modes was also achieved. LSE has pointed out the coherent structured for both cases and the reconstructed velocity fields are in well agreement with the instantaneous velocity fields.

  20. Characteristics of hydrocarbon uptake in cultures with two liquid phases.

    Science.gov (United States)

    Nakahara, T; Erickson, L E; Gutierrez, J R

    1977-01-01

    In hydrocarbon fermentation, the efficiency of hydrocarbon uptake by cells is one of the keys to the economical production of single-cell protein. This work is concerned with characterization of cultures with two liquid phases for understanding the hydrocarbon uptake process by cells. Batch cultivation of Candida lipolytica was carried out in shaking flasks and in a tower fermentor with motionless mixers. Microscopic observation and cell and hydrocarbon concentration distribution in batch cultivation showed that some cells are attached to the large oil drops and others are free from them. Interfacila tension between oil and water and Sauter mean drop size decreased as cultivation proceeded. On the basis of the experimental results, the process of hydrocarbon uptake by cells is discussed.

  1. Transient liquid-phase bonding of ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Noto, H., E-mail: s25093145w@eng.hokudai.ac.jp [Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, N-13, W-8, Kita-ku, Hokkaido Sapporo 060-8628 (Japan); Ukai, S.; Hayashi, S. [Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, N-13, W-8, Kita-ku, Hokkaido Sapporo 060-8628 (Japan)

    2011-10-01

    The use of transient liquid-phase bonding of 9CrODS steels using Fe-3B-2Si-0.5C filler was investigated for bonding temperature of 1180 deg. C and hold times of 0.5-4.0 h. The sequential process, consisting of isothermal melting, solidification and homogenization, was confirmed for bonding the 9CrODS steel. The precipitation of chromium boride found in 19CrODS steel is avoided in 9CrODS steel due to the lower Cr content. Silicon tends to be slightly enriched inside the bonding zone. Agglomeration and coarsening of Y{sub 2}O{sub 3} particles in 9CrODS steel lead to softening inside the bonding zone formed by incipient melting of the foil bonding alloy, and in a diffusion affected zone (DAZ) adjacent to the bonding zone.

  2. Preparation of ITO Nanoparticles by Liquid Phase Coprecipitation Method

    Directory of Open Access Journals (Sweden)

    Zhanlai Ding

    2010-01-01

    Full Text Available The nanoscale indium tin oxide (ITO particles are synthesied by liquid phase coprecipitation method under given conditions with solution of indium chloride, tin chloride, and ammonia. The absolute ethyl alcohol or deionized water was used as solvent and the dodecylamine or hexadecylamine surfactant was used as a dispersant in the reaction system. The sample powder was characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, and high-resolution electron microscopy (HRTEM. Based on the transmission electron micrograph, the influences of the two different solvents and the two different dispersants on the nanoparticle size and dispersion were studied, respectively. The results showed that the ITO particles are finely crystallized body-centered cubic structure. The particle size has distributed in 30 nm to 90 nm.

  3. Densification and mechanical properties of liquid phase sintered tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Pinatti, D.G. [EEL-USP, Polo Urbo Industrial, Gleba AI6, Lorena/SP (Brazil); Holanda, J.N.F. de [Universidade Estadual do Norte Fluminense - UENF/CCT/PPGECM, Campos dos Goytacazes/RJ (Brazil); Gomes, U.U. [DFTE-UFRN, Natal/RN (Brazil); Filgueira, M.

    2009-10-15

    This paper has as main objective to investigate the influence of nickel (Ni), iron (Fe) and copper (Cu) addition on the tantalum (Ta) powder processing, by promoting a liquid phase sintering (LPS). The role of these metals is to lower the Ta sintering temperature, maintaining good densification and mechanical properties. Ni, Fe and Cu 1wt% additions to Ta powder were performed. Samples were cold pressed at 350 MPa. Sintering was carried out at 1300 to 2000 C, for 1 hour, under a vacuum of 10{sup -6} Pa. Density, linear shrinkage and activation energy were measured and calculated. Hardness and compression tests were also conducted. Ni was the most promissing Ta LPS activator, once it enabled the best results of densification and mechanical properties. (Abstract Copyright [2009], Wiley Periodicals, Inc.) [German] Verdichtung und mechanische Eigenschaften von fluessigphasengesintertem Tantalum. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  4. Comparison of liquid and supercritical fluid chromatography mobile phases for enantioselective separations on polysaccharide stationary phases.

    Science.gov (United States)

    Khater, Syame; Lozac'h, Marie-Anne; Adam, Isabelle; Francotte, Eric; West, Caroline

    2016-10-07

    Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating the scene and are often seen as complementary techniques. Nowadays, for economic and ecologic reasons, SFC may be preferred over normal-phase HPLC (NPLC) as it allows significant reductions in solvent consumption. However, the transfer of NPLC methods to SFC is not always straightforward. In this study, we compare the retention of achiral molecules and separation of enantiomers under supercritical fluid (carbon dioxide with ethanol or isopropanol) and liquid normal-phase (heptane with ethanol or isopropanol) elution modes with polysaccharide stationary phases in order to explore the differences between the retention and enantioseparation properties between the two modes. Chemometric methods (namely quantitative structure-retention relationships and discriminant analysis) are employed to compare the results obtained on a large set of analytes (171 achiral probes and 97 racemates) and gain some understanding on the retention and separation mechanisms. The results indicate that, contrary to popular belief, carbon dioxide - solvent SFC mobile phases are often weaker eluents than liquid mobile phases. It appears that SFC and NPLC elution modes provide different retention mechanisms. While some enantioseparations are unaffected, facilitating the transfer between the two elution modes, other enantioseparations may be drastically different due to different types and strength of interactions contributing to enantioselectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Amphiphilic and phase-separable ionic liquids for biomass processing.

    Science.gov (United States)

    Holding, Ashley J; Heikkilä, Mikko; Kilpeläinen, Ilkka; King, Alistair W T

    2014-05-01

    One main limiting factor for the technoeconomics of future bioprocesses that use ionic liquids (ILs) is the recovery of the expensive and potentially toxic IL. We have demonstrated a new series of phase-separable ionic liquids, based on the hydrophobic tetraalkylphosphonium cation ([PRRRR](+)), that can dissolve lignin in the neat state but also hemicellulose and high-purity cellulose in the form of their electrolyte solutions with dipolar aprotic solvents. For example, the IL trioctylmethylphosphonium acetate ([P8881][OAc]) was demonstrated to dissolve up to 19 wt % of microcrystalline cellulose (MCC) at 60 °C with the addition of 40 wt % of DMSO. It was found that the MCC saturation point is dependent on the molar ratio of DMSO and IL in solution. At the optimum saturation, a ∼1:1 molar ratio of [P8881][OAc] to anhydroglucose units is observed, which demonstrates highly efficient solvation. This is attributed to the positive contribution that these more amphiphilic cation-anion pairs provide, in the context of the Lindman hypothesis. This effective dissolution is further illustrated by solution-state HSQC NMR spectroscopy on MCC. Finally, it is also demonstrated that these electrolytes are phase separable by the addition of aqueous solutions. The addition of 10 % NaOAc solution allows a near quantitative recovery of high-purity [P8881][OAc]. However, increased volumes of aqueous solution reduced the recovery. The regenerated material was found to partially convert into the cellulose II crystalline polymorph. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Refining effect of the liquid phase (in coal hydrogenation)

    Energy Technology Data Exchange (ETDEWEB)

    Hupfer; Leonhardt

    1942-11-07

    Experiments were run in a 10-liter oven at 600 atm. on various starting materials to determine what percentage of the original content of nitrogen, oxygen, and sulfur impurities were removed during liquid-phase processing. It was determined that the liquid phase removed most of these impurities, with nitrogen being affected to a lesser extent than the other two. In general, the raw materials which could most easily be hydrogenated had the greatest percentage of impurities removed. Also, in general, the more drastic the processing, the more effective the impurity-removal, especially in the case of nitrogen. Removal of oxygen as oxides of carbon happened in the case of brown coal to about twice the extent that it did in the case of bituminous coal, and happened to an even greater extent in the case of high-temperature tar. In the case of sulfur, the following percentages were removed in the following processes: 79% in processing low-temperature-carbonization tar to heavy oil, 75% to 87% in processing high-temperature-carbonization tar to heavy oil, 82% to 92% in processing high-temperature-carbonization tar to gasoline and middle oil, 80% to 97% in processing bituminous coal to gasoline and middle oil, and 86% to 89% in processing brown coal to gasoline and middle oil. In the case of oxygen, the corresponding figures (in the same order) were 73%, 36% to 70%, 44% to 70%, 86% to 91%, and 89% to 92%. In the case of nitrogen, they were 56%, 38% to 51%, 53% to 73%, 60% to 67%, and 64% to 79%. 1 table.

  7. The relationship between gut hormone secretion and gastric emptying in different phases of the migrating motor complex

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, L.; Oester-Joergensen, E.; Quist, N. [Odense University Hospital, Odense (Denmark); and others

    1996-05-01

    No studies are available on the relationship between the response of gut hormones and gastric emptying in different phases of the migrating motor complex. This study examined whether basal gut hormone concentrations in plasma before food ingestion are predictors of emptying characteristics and whether different hormone secretion patterns are associated with specific alteration in emptying rate. 12 healthy men were examined on two occasion: one with meal ingestion in phase I and the other with meal ingestion in phase II. The meal consisted of an omelette labelled with {sup 99m}Tc followed by 150 ml water labelled with {sup 111}In. Plasma concentrations of gastrin, cholecystokinin, motilin, and peptide YY were measured in the fasting state, immediately after food ingestion, and at 15 min-min intervals in the postprandial period. New findings from the present study include a higher incremental integrated postprandial motilin response in phase I than in phase II, and a linear relationship between median total integrated motilin response and solid emptying at 120 min in phase I. Furthermore, in phase I a linear relationship between total integrated area of cholecystokinin and solid emptying at 120 min was demonstrated. The findings from the present investigation have to be considered in the future design of studies that focus on postprandial release of gastrointestinal hormones. The transition from phase III to phase I is a reproducible and easily recognized pressure event. Therefore, the authors recommend the use of food ingestion immediately after termination of duodenal phase III. 14 refs.

  8. Development of a sensitive solid-phase radioimmunoassay for melanin-concentrating hormone

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, A.N.; Baumann, J.B.; Girard, J. (Univ. Children' s Hospital, Basel (Switzerland)); Baker, B.I.; Kishida, M. (Univ. of Bath (England))

    1989-01-01

    A two-step solid-phase radioimmunoassay for melanin-concentrating hormone (MCH) was developed for direct determination of the hormone in plasma samples. To this end, synthetic MCH was coupled to bovine thyreoglobulin and the complex was injected into rabbits. Specific antisera of high titer were obtained which did not crossreact with other hormones. The IgGs were chemically linked to immunobeads, an acrylamide/acrylic acid polymer matrix. In the first step, plasma MCH was immunoextracted by incubation of diluted plasma samples with anti-MCH immunobeads. In the second step, the washed polymer was incubated with radioiodinated MCH tracer for titration of non-occupied sites. This procedure made it possible to determine as little as 4 pg MCH per ml of plasma. Application of the radioimmunoassay to plasma levels of black or white background-adapted trout showed a marked difference in circulating MCH: while trout on a black background contained a mean value of 29 {plus minus} 5.6 pg/ml, animals on a white background had 106 {plus minus} 19 pg/ml.

  9. Supported imidazolium ionic liquid phases: a new material for solid-phase extraction.

    Science.gov (United States)

    Fontanals, Núria; Ronka, Sylwia; Borrull, Francesc; Trochimczuk, Andrzej W; Marcé, Rosa M

    2009-11-15

    This study reports a material that is based on the concept of ionic liquid analogue: a slightly crosslinked polymer-supported imidazolium trifluoroacetate salt (IL-CF(3)COO(-)) that favorably combines the properties of ionic liquids (ILs) and the advantages of a solid support. The ionic liquid-supported material was evaluated for the first time as a solid-phase extraction (SPE) sorbent for selectively and quantitatively extracting pharmaceuticals from aqueous samples. The novel IL-CF(3)COO(-) was evaluated under reversed-phase (RP), weak anion exchange (WAX), strong anion exchange (SAX) and strong cation exchange (SCX) SPE procedures, and we found that SAX conditions are the most suitable for investigating the behaviour of the IL-CF(3)COO(-) material. Under SAX conditions, the IL-CF(3)COO(-) material was capable of selectively and quantitatively extracting a group of acidic compounds from aqueous samples, while washing basic analytes that were also present in the sample. The SPE method using IL-CF(3)COO(-) material was used to analyse 1000 ml of different aqueous samples (ultrapure, tap and river) with complete recovery of the acidic compounds studied. Moreover, the method provided clean chromatogram and high recoveries when percolating complex real samples, such as 1000 ml of river water and 250 ml of effluent wastewater from a sewage treatment plant spiked at low levels with the analytes studied.

  10. Effect of a phase advance and phase delay of the 24-h cycle on energy metabolism, appetite, and related hormones.

    Science.gov (United States)

    Gonnissen, Hanne K J; Rutters, Femke; Mazuy, Claire; Martens, Eveline A P; Adam, Tanja C; Westerterp-Plantenga, Margriet S

    2012-10-01

    The disruption of the circadian system has been associated with the development of obesity. We examined the effects of circadian misalignment on sleep, energy expenditure, substrate oxidation, appetite, and related hormones. Thirteen subjects [aged 24.3 ± 2.5 (mean ± SD) y; BMI (in kg/m²): 23.6 ± 1.7 (mean ± SD)] completed a randomized crossover study. For each condition, subjects stayed time blinded in the respiration chamber during 3 light-entrained circadian cycles that resulted in a phase advance (3 × 21 h) and a phase delay (3 × 27 h) compared with during a 24-h cycle. Sleep, energy expenditure, substrate oxidation, and appetite were quantified. Blood and saliva samples were taken to determine melatonin, glucose, insulin, ghrelin, leptin, glucagon-like peptide 1 (GLP-1), and cortisol concentrations. Circadian misalignment, either phase advanced or phase delayed, did not result in any changes in appetite or energy expenditure, whereas meal-related blood variables (glucose, insulin, ghrelin, leptin, and GLP-1) followed the new meal patterns. However, phase-advanced misalignment caused flattening of the cortisol-secretion pattern (P sleep (P sleeping metabolic rate (P = 0.02), increased glucose (P = 0.02) and decreased GLP-1 (P = 0.02) concentrations, and increased carbohydrate oxidation (P = 0.01) and decreased protein oxidation (P = 0.003). The main effect of circadian misalignment, either phase advanced or phase delayed, is a concomitant disturbance of the glucose-insulin metabolism and substrate oxidation, whereas the energy balance or sleep is not largely affected. Chronically eating and sleeping at unusual circadian times may create a health risk through a metabolic disturbance. This trial was registered at the International Clinical Trials Registry Platform (http://apps.who.int/trialsearch/) as NTR2926.

  11. Dynamic Modeling of the Two-Phase Leakage Process of Natural Gas Liquid Storage Tanks

    National Research Council Canada - National Science Library

    Xia Wu; Changjun Li; Yufa He; Wenlong Jia

    2017-01-01

    ... of the NGL’s pressure, temperature and phase state in the tank and across the leak hole. The methods available in the literature rarely consider the liquid/vapor phase transition of the NGL during such a process...

  12. Facile synthesis and properties of CdSe quantum dots in a novel two-phase liquid/liquid system

    Science.gov (United States)

    Wang, Jidong; Wang, Xiaoyu; Tang, Hengshan; Gao, Zehua; He, Shengquan; Ke, Dandan; Zheng, Yue; Han, Shumin

    2017-10-01

    High-quantity CdSe QDs were synthesized in a novel two-phase liquid/liquid system. This system, ODE/water was stable and as-used solvents were almost nontoxic. The methodology leading to the successful synthesis of CdSe QDs was a typical, one-pot approach and the obtained CdSe QDs with zinc-blende phase structure exhibited excellent optical properties, narrow size distribution, higher particle uniformity and crystallinity. The mechanism of nucleation and growth of CdSe QDs were discussed by the possible thermodynamic equilibrium existing in ODE/water interface. This two-phase liquid/liquid system would broaden the synthesis of other semiconductor QDs.

  13. Phase transformation and liquid density redistribution during solidification of Ni-based superalloy Inconel 718

    Directory of Open Access Journals (Sweden)

    Wang Ling

    2012-08-01

    Full Text Available The influences of chemical segregation and phase transformation on liquid density variation during solidification of Ni-based supperalloy Inconel 718 were investigated using SEM and EDS. It was found that significant segregation in liquid prompts high Nb phase to precipitate directly from liquid, which results in the redistribution of alloy elements and liquid density in their vicinity. The term “inter-precipitate liquid density” is therefore proposed and this concept should be applied to determine the solidification behavior of superalloy Inconel 718.

  14. Non-equilibrium phase transitions in a liquid crystal.

    Science.gov (United States)

    Dan, K; Roy, M; Datta, A

    2015-09-07

    The present manuscript describes kinetic behaviour of the glass transition and non-equilibrium features of the "Nematic-Isotropic" (N-I) phase transition of a well known liquid crystalline material N-(4-methoxybenzylidene)-4-butylaniline from the effects of heating rate and initial temperature on the transitions, through differential scanning calorimetry (DSC), Fourier transform infrared and fluorescence spectroscopy. Around the vicinity of the glass transition temperature (Tg), while only a change in the baseline of the ΔCp vs T curve is observed for heating rate (β) > 5 K min(-1), consistent with a glass transition, a clear peak for β ≤ 5 K min(-1) and the rapid reduction in the ΔCp value from the former to the latter rate correspond to an order-disorder transition and a transition from ergodic to non-ergodic behaviour. The ln β vs 1000/T curve for the glass transition shows convex Arrhenius behaviour that can be explained very well by a purely entropic activation barrier [Dan et al., Eur. Phys. Lett. 108, 36007 (2014)]. Fourier transform infrared spectroscopy indicates sudden freezing of the out-of-plane distortion vibrations of the benzene rings around the glass transition temperature and a considerable red shift indicating enhanced coplanarity of the benzene rings and, consequently, enhancement in the molecular ordering compared to room temperature. We further provide a direct experimental evidence of the non-equilibrium nature of the N-I transition through the dependence of this transition temperature (TNI) and associated enthalpy change (ΔH) on the initial temperature (at fixed β-values) for the DSC scans. A plausible qualitative explanation based on Mesquita's extension of Landau-deGennes theory [O. N. de Mesquita, Braz. J. Phys. 28, 257 (1998)] has been put forward. The change in the molecular ordering from nematic to isotropic phase has been investigated through fluorescence anisotropy measurements where the order parameter, quantified by the

  15. Exploring Genitoanal Injury and HIV Risk Among Women: Menstrual Phase, Hormonal Birth Control, and Injury Frequency and Prevalence.

    Science.gov (United States)

    Brawner, Bridgette M; Sommers, Marilyn S; Moore, Kendra; Aka-James, Rose; Zink, Therese; Brown, Kathleen M; Fargo, Jamison D

    2016-02-01

    Genital, anal, and oral injuries sustained from sexual intercourse may explain HIV transmission among women. We determined the variability in genitoanal injury frequency and prevalence in women after consensual sexual intercourse, exploring the role of menstrual phase and hormonal birth control. We used a longitudinal observational design with a convenience sample of 393 women aged 21 years and older. Participants had a baseline interview with gynecological examination, followed by consensual sexual intercourse with a male partner and a second gynecological examination. We analyzed injury prevalence with logistic regression and injury frequency with negative binomial regression among women who were (1) menstrual, not using hormonal birth control, (2) menstrual, using hormonal birth control, or (3) menopausal. We also compared injury among menstrual women in the follicular, ovulatory, and luteal phases. Women using hormonal birth control had 38% more external genitalia injuries [adjusted rate ratio (ARR) = 1.38, P = 0.030] and more than twice the anal injuries (ARR = 2.67, P = 0.005) as the nonhormonal birth control menstruating group. Menopausal women had more than 3 times the anal injuries (ARR = 3.36, P = 0.020) than those in the nonhormonal menstrual group. Among menstrual women, those in the follicular phase had a greater prevalence and frequency of external genitalia injuries than those in other phases. Increased rates of postcoital genitoanal injuries are noted among women using hormonal birth control and/or in the follicular phase of menstruation. Biological factors that influence women's risk for HIV warrant further investigation.

  16. Liquid Crystal Phases of Colloidal Platelets and their Use as Nanocomposite Templates

    NARCIS (Netherlands)

    Mourad, M.C.D.|info:eu-repo/dai/nl/304837563

    2009-01-01

    This thesis explores the gelation and liquid crystal phase behavior of colloidal dispersions of platelike particles as well as the use of such dispersions for the generation of nanocomposites. We report on the sol-gel, sol-glass and liquid crystal phase transitions of positively charged colloidal

  17. Basic and mixed models for computer simulation of liquid phase sintering of a porous structure

    Directory of Open Access Journals (Sweden)

    Nikolić Z.S.

    2007-01-01

    Full Text Available A two-dimensional method based on basic and mixed models for simulation of liquid phase sintering of a porous structure will be developed. These models will be tested in order to conduct a study of diffusion phenomena and gravitational effects on microstructural evolution during liquid phase sintering of a W-Ni system.

  18. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Science.gov (United States)

    2010-07-01

    ... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Liquid, suspended particulate, and solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION...

  19. Positron annihilation in benzene and cyclohexane: a comparison between gas and liquid phase

    Science.gov (United States)

    Fedus, Kamil

    2015-06-01

    A comparative study about positron annihilation in gas and liquid phases of two non-polar ring molecules: benzene (C6H6) and cyclohexane (C6H12) is presented including the most recent experimental and theoretical achievements. In addition the preliminary results of positron annihilation lifetime measurements in a liquid phase at room temperature for these two molecules are reported.

  20. Centrifugal contactor with liquid mixing and flow control vanes and method of mixing liquids of different phases

    Science.gov (United States)

    Jubin, Robert T.; Randolph, John D.

    1991-01-01

    The invention is directed to a centrifugal contactor for solvent extraction systems. The centrifugal contactor is provided with an annular vertically oriented mixing chamber between the rotor housing and the rotor for mixing process liquids such as the aqueous and organic phases of the solvent extraction process used for nuclear fuel reprocessing. A set of stationary helically disposed vanes carried by the housing is in the lower region of the mixing chamber at a location below the process-liquid inlets for the purpose of urging the liquids in an upward direction toward the inlets and enhancing the mixing of the liquids and mass transfer between the liquids. The upper region of the mixing vessel above the inlets for the process liquids is also provided with a set helically disposed vanes carried by the housing for urging the process liquids in a downward direction when the liquid flow rates through the inlets are relatively high and the liquids contact the vane set in the upper region. The use of these opposing vane sets in the mixing zone maintains the liquid in the mixing zone at suitable levels.

  1. Terahertz saturable absorbers from liquid phase exfoliation of graphite.

    Science.gov (United States)

    Bianchi, Vezio; Carey, Tian; Viti, Leonardo; Li, Lianhe; Linfield, Edmund H; Davies, A Giles; Tredicucci, Alessandro; Yoon, Duhee; Karagiannidis, Panagiotis G; Lombardi, Lucia; Tomarchio, Flavia; Ferrari, Andrea C; Torrisi, Felice; Vitiello, Miriam S

    2017-06-15

    Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ∼80%, almost one order of magnitude larger than that reported to date at THz frequencies. Fourier-transform infrared spectroscopy provides evidence of intraband-controlled absorption bleaching. These results pave the way to the integration of graphene-based SA with electrically pumped THz semiconductor micro-sources, with prospects for applications where excitation of specific transitions on short time scales is essential, such as time-of-flight tomography, coherent manipulation of quantum systems, time-resolved spectroscopy of gases, complex molecules and cold samples and ultra-high speed communications, providing unprecedented compactness and resolution.

  2. Comparison of liquid phase operations, Poelitz and Gelsenberg

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R.; Schappert, H.; Gromann, F.; Berger; Jakob; Klinkhardt; Friemelt; Egli, O.I.

    1942-06-18

    A comparison is presented of liquid phase coal hydrogenation at the Poelitz and Gelsenberg plants for January through April 1942. Coal analyses are compared for water and ash content in both raw and cleaned coal. Comparisons of catalyst with reference to dried coal are given for Bayer mass, iron sulfate, and sulfigran. Coal paste solid content and residue composition are also compared. High pressure oil yield is compared based on the available oil yield plus the losses occurring in low pressure operations. Comparisons are also given for amount of solids in centrifuge residue, low temperature carbonization analysis and theoretical liquefaction. Since calculation of gasification did not rest on a sound basis, gasification comparisons are computed from the difference between theoretical liquefaction and high pressure oil yield. Balances for the two plants are compared in a table. Differences in operating results are said to have arisen from varying carbon-content of coal, variable conversion, variable losses in residue processing, variable gasification and indeterminate gas and oil losses, and variable gasoline and lubricating oil concentration in the oil yield. 1 table.

  3. Terahertz saturable absorbers from liquid phase exfoliation of graphite

    Science.gov (United States)

    Bianchi, Vezio; Carey, Tian; Viti, Leonardo; Li, Lianhe; Linfield, Edmund H.; Davies, A. Giles; Tredicucci, Alessandro; Yoon, Duhee; Karagiannidis, Panagiotis G.; Lombardi, Lucia; Tomarchio, Flavia; Ferrari, Andrea C.; Torrisi, Felice; Vitiello, Miriam S.

    2017-06-01

    Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ~80%, almost one order of magnitude larger than that reported to date at THz frequencies. Fourier-transform infrared spectroscopy provides evidence of intraband-controlled absorption bleaching. These results pave the way to the integration of graphene-based SA with electrically pumped THz semiconductor micro-sources, with prospects for applications where excitation of specific transitions on short time scales is essential, such as time-of-flight tomography, coherent manipulation of quantum systems, time-resolved spectroscopy of gases, complex molecules and cold samples and ultra-high speed communications, providing unprecedented compactness and resolution.

  4. GaSb film growth by liquid phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Cruz, M.L.; Martinez-Juarez, J.; Lopez-Salazar, P. [CIDS-ICUAP, BUAP, Av. 14 Sur y San Claudio, C.U. Edif.103C, Col. Sn Manuel, C.P. 72570, Puebla, Pue. (Mexico); Diaz, G.J. [Centro de Investigacion y Estudios Avanzados, IPN, Av. IPN 2508, Col. Sn. Pedro Zacatenco, C.P. 07360, D.F. (Mexico)

    2010-04-15

    Doped GaSb (Gallium Antimonide) films on p-GaSb substrates have been obtained by means of a low-cost and fast-growth method: the liquid phase epitaxy (LPE) technique. The growth temperature was 400 C, and the growth time was varied between1 and 5 min. Characterization of the films was performed by means of high resolution X-ray Diffraction, low temperature-photoluminescence and current-voltage curve measurements. The X-ray diffraction pattern confirms a zincblende-type crystal structure with a high-thin peak centred at 30.36 . The PL spectra at 27 K allowed to confirm the band-gap energy to be 0.8 eV and the I-V curves presented a PN junction behavior which corresponds to the obtained structured. Metal contacts of Au-Zn and Au-Ge were placed to perform electrical characterization (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Homogeneous Liquid Phase Transfer of Graphene Oxide into Epoxy Resins.

    Science.gov (United States)

    Amirova, Lyaysan; Surnova, Albina; Balkaev, Dinar; Musin, Delus; Amirov, Rustem; Dimiev, Ayrat M

    2017-04-05

    The quality of polymer composite materials depends on the distribution of the filler in the polymer matrix. Due to the presence of the oxygen functional groups, graphene oxide (GO) has a strong affinity to epoxy resins, providing potential opportunity for the uniform distribution of GO sheets in the matrix. Another advantage of GO over its nonoxidized counterpart is its ability to exfoliate to single-atomic-layer sheets in water and in some organic solvents. However, these advantages of GO have not yet been fully realized due to the lack of the methods efficiently introducing GO into the epoxy resin. Here we develop a novel homogeneous liquid phase transfer method that affords uniform distribution, and fully exfoliated condition of GO in the polymer matrix. The most pronounced alteration of properties of the cured composites is registered at the 0.10%-0.15% GO content. Addition of as little as 0.10% GO leads to the increase of the Young's modulus by 48%. Moreover, we demonstrate successful introduction of GO into the epoxy matrix containing an active diluent-modifier; this opens new venues for fabrication of improved GO-epoxy-modifier composites with a broad range of predesigned properties. The experiments done on reproducing the two literature methods, using alternative GO introduction techniques, lead to either decrease or insignificant increase of the Young's modulus of the resulting GO-epoxy composites.

  6. Leukocyte changes across menstruation, ovulation, and mid-luteal phase and association with sex hormone variation.

    Science.gov (United States)

    Nowak, Judyta; Borkowska, Barbara; Pawlowski, Boguslaw

    2016-09-10

    Total leukocyte count (white blood cells-WBC) and the count of each subpopulation vary across the menstrual cycle, but results of studies examining the time and direction of these changes are inconsistent and methodologically flawed. Besides, no previous study focused on leukocyte count on the day of ovulation. Blood samples were obtained from 37 healthy and regularly cycling women aged 19.8-36.1 years. Samples were taken three times: during menstruation (M), ovulation (O), and in the mid-luteal phase (ML). WBC, neutrophils, lymphocytes, mixed cells, progesterone (P,) and estradiol (E) were measured in each of the three target phases of the cycle. Compared to menstruation, WBC (P = 0.002) and neutrophils (P < 0.001) increased around ovulation and remained stable in the mid-luteal phase, whereas lymphocyte and mixed cell counts did not change throughout the menstrual cycle. There were some correlations of sex hormone variation with leukocyte changes between M and O (positive for E and WBC, negative for P and WBC and for P and neutrophil count; P < 0.05), but not between O and ML. Peripheral leukocyte changes taking place in the second half of the cycle are already observable on the day of ovulation and they are associated with sex hormone variation. We speculate that these changes may lead to increased immune protection against pathogens at a time when fertilization and implantation typically occur. Am. J. Hum. Biol. 28:721-728, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  7. The relationship between gut hormone secretion and gastric emptying in different phases of the migrating motor complex

    DEFF Research Database (Denmark)

    Rasmussen, L; Oster-Jørgensen, E; Qvist, N

    1996-01-01

    BACKGROUND: No studies are available on the relationship between the response of gut hormones and gastric emptying in different phases of the migrating motor complex. This study examined whether basal gut hormone concentrations in plasma before food ingestion are predictors of emptying...... characteristics and whether different hormone secretion patterns are associated with specific alterations in emptying rate. METHODS: Twelve healthy men were examined on two occasions: one with meal ingestion in phase I and the other with meal ingestion in phase II. The meal consisted of an omelette labelled...... with 99mTc followed by 150 ml water labelled with 111In. Plasma concentrations of gastrin, cholecystokinin, motilin, and peptide YY were measured in the fasting state, immediately after food ingestion, and at 15-min intervals in the postprandial period. RESULTS: New findings from the present study include...

  8. Simultaneous determination of veterinary antibiotics and hormone in broiler manure, soil and manure compost by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ho, Y B; Zakaria, Mohamad Pauzi; Latif, Puziah Abdul; Saari, Nazamid

    2012-11-02

    A multi-residue analytical method was developed to quantify nine antibiotics and one hormone in soil, broiler manure and manure compost. The developed method was based on ultrasonic extraction with MeOH:ACN:EDTA:McIlvaine buffer, solid phase extraction (SPE) using HLB (3 cc/60 mg) cartridge, followed by instrumental analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with 25 min total run time. It was validated and tested on soil, broiler manure and manure compost samples and showed that the method is able to simultaneously detect and quantify the target analytes with good selectivity and sensitivity. The developed method was linear in a concentration range from its instrumental quantification limit (IQL) to 500 ng/mL, with correlation coefficients higher than 0.999. The overall method performance was good for the majority of the analytes, with recoveries range from 63% to 121% in all the sample matrices. The method quantification limit (MQL) for the 10 target analytes in the soil, broiler manure and manure compost samples were 2-10, 3-16 and 5-15 μg/kg dry weight (DW), respectively. The method has also included tilmicosin, an antibiotic known to be reported in the environment for the first time. The developed method was then applied on broiler manure samples and its relative manure amended agricultural soil samples to identify and quantify veterinary antibiotic and hormone residues in the environment. These analytes were detected in broiler manure and soil samples, with maximum concentrations reaching up to 78516.1 μg/kg DW (doxycycline) and 1331.4 μg/kg DW (flumequine), respectively. The results showed that the method can potentially be adopted for the analysis of veterinary antibiotic and hormone wastes in solid environmental matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Control of the phase composition and morphology of a Cu-Sb eutectic alloy via liquid-liquid structure transition

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhong-Yue; Zu, Fang-Qiu; Li, Xiao-Yun [Liquid/Solid Metal Processing Institute, School of Materials Science and Engineering, Hefei University of Technology, Hefei (China)

    2012-09-15

    The current paper focuses on the solidification characteristics of a Cu-Sb eutectic alloy in its different liquid states. Liquid alloy resistivity-temperature patterns suggest an irreversible temperature-induced liquid-liquid structure transition (TI-LLST), and a reversible TI-LLST occurred during the heating-cooling runs. A set of solidification experiments was conducted based on the results. The irreversible TI-LLST caused an enhanced solidification undercooling, increased solidification rate, refined regular eutectic morphologies, and absence of a pre-eutectic Cu{sub 2}Sb phase. The reversible TI-LLST resulted in different phase compositions and eutectic structures. The mechanisms behind these transitions are also briefly discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Morphogenesis of liquid crystal topological defects during the nematic-smectic A phase transition

    Science.gov (United States)

    Gim, Min-Jun; Beller, Daniel A.; Yoon, Dong Ki

    2017-05-01

    The liquid crystalline phases of matter each possess distinct types of defects that have drawn great interest in areas such as topology, self-assembly and material micropatterning. However, relatively little is known about how defects in one liquid crystalline phase arise from defects or deformations in another phase upon crossing a phase transition. Here, we directly examine defects in the in situ thermal phase transition from nematic to smectic A in hybrid-aligned liquid crystal droplets on water substrates, using experimental, theoretical and numerical analyses. The hybrid-aligned nematic droplet spontaneously generates boojum defects. During cooling, toric focal conic domains arise through a sequence of morphological transformations involving nematic stripes and locally aligned focal conic domains. This simple experiment reveals a surprisingly complex pathway by which very different types of defects may be related across the nematic-smectic A phase transition, and presents new possibilities for controlled deformation and patterning of liquid crystals.

  11. Ionic liquids as stationary phases in gas chromatography--an LSER investigation of six commercial phases and some applications.

    Science.gov (United States)

    Weber, Waldemar; Andersson, Jan T

    2014-09-01

    The separation properties of six novel stationary phases for gas chromatography, commercially available from Sigma-Aldrich (Supelco) and based on ionic liquids (ILs), were investigated. The linear solvation energy relationship model (LSER) was used to describe the molecular interactions between these stationary phases and 30 solutes. The solutes belong to different groups of compounds, like haloalkanes, alcohols, ketones, aromatics, aliphatics, and others. A good description of different interactions, as described by the LSER model, could be achieved. The calculated values of system constants for the ionic liquid phases were compared with constants of commonly used standard phases like a 5 % phenyl/95 % dimethyl siloxane and a polyethylene glycol phase. The solute descriptors are in good agreement with those found by previous authors who have used the LSER model for 44 different ionic liquids as stationary phase. The experiments were carried out at two temperatures to evaluate the influence on the phase parameters and separation characteristics. The interactions of different functional groups with the IL phases are discussed. These novel IL phases are a promising replacement of or an addition to common polar phases. Based on the evaluated phase properties, several possibilities for applications of these novel phases are shown.

  12. A Liquid-Liquid Thermoelectric Heat Exchanger as a Heat Pump for Testing Phase Change Material Heat Exchangers

    Science.gov (United States)

    Sheth, Rubik B.; Makinen, Janice; Le, Hung V.

    2016-01-01

    The primary objective of the Phase Change HX payload on the International Space Station (ISS) is to test and demonstrate the viability and performance of Phase Change Material Heat Exchangers (PCM HX). The system was required to pump a working fluid through a PCM HX to promote the phase change material to freeze and thaw as expected on Orion's Multipurpose Crew Vehicle. Due to limitations on ISS's Internal Thermal Control System, a heat pump was needed on the Phase Change HX payload to help with reducing the working fluid's temperature to below 0degC (32degF). This paper will review the design and development of a TEC based liquid-liquid heat exchanger as a way to vary to fluid temperature for the freeze and thaw phase of the PCM HX. Specifically, the paper will review the design of custom coldplates and sizing for the required heat removal of the HX.

  13. Double-twist cylinders in liquid crystalline cholesteric blue phases observed by transmission electron microscopy

    OpenAIRE

    Shu Tanaka; Hiroyuki Yoshida; Yuto Kawata; Ryusuke Kuwahara; Ryuji Nishi; Masanori Ozaki

    2015-01-01

    Cholesteric blue phases are liquid crystalline phases in which the constituent rod-like molecules spontaneously form three-dimensional, helical structures. Despite theoretical predictions that they are composed of cylindrical substructures within which the liquid crystal molecules are doubly twisted, real space observation of the arrangement of such structures had not been performed. Through transmission electron microscopy of photopolymerized blue phases with controlled lattice plane orienta...

  14. Rapid removal of nitrobenzene in a three-phase ozone loaded system with gas-liquid-liquid

    Science.gov (United States)

    Li, Shiyin; Zhu, Jiangpeng; Wang, Guoxiang; Ni, Lixiao; Zhang, Yong; Green, Christopher T.

    2015-01-01

    This study explores the removal rate of nitrobenzene (NB) using a new gas-liquid-liquid (G-L-L) three-phase ozone loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including 1) initial pH, 2) initial NB dosage, 3) gaseous ozone dosage, 4) free radical scavenger, 5) FDC pre-aerated gaseous ozone, and 6) reuse of FDC. The NB removal rate is positively affected by the first three factors. Compared with the conventional gas-liquid (water) (G-L) two-phase ozonation system, the free radical scavenger (tertiary butyl alcohol) has much less influence on the removal rate of NB in the G-L-L system. The FDC loaded ozone acts as an ozone reservoir and serves as the main reactive phase in the G-L-L three-phase system. The reuse of FDC has little influence on the removal rate of NB. These experimental results suggest that the oxidation efficiency of ozonation in the G-L-L three-phase system is better than that in the conventional G-L two-phase system.

  15. Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

    Science.gov (United States)

    A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

  16. Sleeve gastrectomy effects on hunger, satiation, and gastrointestinal hormone and motility responses after a liquid meal test.

    Science.gov (United States)

    Mans, Esther; Serra-Prat, Mateu; Palomera, Elisabet; Suñol, Xavier; Clavé, Pere

    2015-09-01

    The relation between hunger, satiation, and integrated gastrointestinal motility and hormonal responses in morbidly obese patients after sleeve gastrectomy has not been determined. The objective was to assess the effects of sleeve gastrectomy on hunger, satiation, gastric and gallbladder motility, and gastrointestinal hormone response after a liquid meal test. Three groups were studied: morbidly obese patients (n = 16), morbidly obese patients who had had sleeve gastrectomy (n = 8), and nonobese patients (n = 16). The participants fasted for 10 h and then consumed a 200-mL liquid meal (400 kcal + 1.5 g paracetamol). Fasting and postprandial hunger, satiation, hormone concentrations, and gastric and gallbladder emptying were measured several times over 4 h. No differences were observed in hunger and satiation curves between morbidly obese and nonobese groups; however, sleeve gastrectomy patients were less hungry and more satiated than the other groups. Antrum area during fasting in morbidly obese patients was statistically significant larger than in the nonobese and sleeve gastrectomy groups. Gastric emptying was accelerated in the sleeve gastrectomy group compared with the other 2 groups (which had very similar results). Gallbladder emptying was similar in the 3 groups. Sleeve gastrectomy patients showed the lowest ghrelin concentrations and higher early postprandial cholecystokinin and glucagon-like peptide 1 peaks than did the other participants. This group also showed an improved insulin resistance pattern compared with morbidly obese patients. Sleeve gastrectomy seems to be associated with profound changes in gastrointestinal physiology that contribute to reducing hunger and increasing sensations of satiation. These changes include accelerated gastric emptying, enhanced postprandial cholecystokinin and glucagon-like peptide 1 concentrations, and reduced ghrelin release, which together may help patients lose weight and improve their glucose metabolism after

  17. Application of hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction techniques in analytical toxicology

    Directory of Open Access Journals (Sweden)

    Vahid Sharifi

    2016-04-01

    Full Text Available The recent developments in hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction are reviewed. Applications of these newly emerging developments in extraction and preconcentration of a vast category of compounds including heavy metals, pesticides, pharmaceuticals and abused drugs in complex matrices (environmental and biological matrices are reviewed and discussed. The new developments in these techniques including the use of solvents lighter than water, ionic liquids and supramolecular solvents are also considered. Applications of these new solvents reduce the use of toxic solvents and eliminate the centrifugation step, which reduces the extraction time.

  18. Enzalutamide monotherapy: Phase II study results in patients with hormone-naive prostate cancer

    DEFF Research Database (Denmark)

    Tombal, Bertrand; Borre, Michael; Rathenborg, Per

    2013-01-01

    response rate (.80% PSA decline at wk 25) was 93%, with a median (range) decrease of 299% (2100, 257) at wk 25. Serum T and estrogen levels increased by a median (range) of 113% (232, 300) and 58% (249, 321) at wk 25, respectively, compared with baseline. 82% of men reported drug-related AEs (mostly Grade...... studies that exclusively enrolled patients with CRPC receiving androgen deprivation therapy (ie, testosterone (T) levels #50 ng/dL), this phase II study assessed the efficacy and safety of ENZA monotherapy in patients who had never received hormone therapy; presenting with non-castrate T levels ($230 ng...... was PSA response (.80% decrease at wk 25). Secondary endpoints included changes in endocrine levels and safety/tolerability. Results: Among 67 men enrolled, the median (range) age was 73 (48, 86) y; 39% had metastases; 36% and 24% had undergone prostatectomy or radiotherapy before study entry. The PSA...

  19. Chiral liquid crystals: the vestigial chiral phases of T, O, I matter

    Science.gov (United States)

    Nissinen, Jaakko; Liu, Ke; Slager, Robert-Jan; Wu, Kai; Zaanen, Jan

    We show how chiral order develops in vestigial isotropic phases of T , O and I liquid crystalline systems in three dimensions. The liquid crystal phases are realized in a lattice model of orientational degrees of freedom with point group symmetries G ⊂ O (3) , represented as O (3) -rotors coupled to G gauge fields. The model incorporates also disclinations via the gauge fields, features an ordered nematic phase with unbroken G rotations at low temperatures and a high temperature isotropic liquid phase. We observe an intermediate phase with spontaneous chirality but isotropic SO (3) symmetry (a liquid) for the gauge groups T, O, and I, the proper symmetry groups of the tetrahedron, cube and icosahedron, respectively. For the other subgroups of SO (3) , Cn <= ∞ and Dn <= ∞, there is generically only a single phase transition from the nematic phase to the isotropic liquid. We discuss the nature of the phase transitions and conditions under which the chiral phase is stabilized by the nematic order parameter fluctuations. The nature of the vestigial chiral phase is reminiscent of the so-called Ising nematic phase in iron based superconductors. Research supported by the Netherlands foundation for Fundamental Research of Matter (FOM).

  20. Sedimentation of a two-dimensional colloidal mixture exhibiting liquid-liquid and gas-liquid phase separation: a dynamical density functional theory study.

    Science.gov (United States)

    Malijevský, Alexandr; Archer, Andrew J

    2013-10-14

    We present dynamical density functional theory results for the time evolution of the density distribution of a sedimenting model two-dimensional binary mixture of colloids. The interplay between the bulk phase behaviour of the mixture, its interfacial properties at the confining walls, and the gravitational field gives rise to a rich variety of equilibrium and non-equilibrium morphologies. In the fluid state, the system exhibits both liquid-liquid and gas-liquid phase separation. As the system sediments, the phase separation significantly affects the dynamics and we explore situations where the final state is a coexistence of up to three different phases. Solving the dynamical equations in two-dimensions, we find that in certain situations the final density profiles of the two species have a symmetry that is different from that of the external potentials, which is perhaps surprising, given the statistical mechanics origin of the theory. The paper concludes with a discussion on this.

  1. Multiple Reaction Monitoring Mode Based Liquid Chromatography-Mass Spectrometry Method for Simultaneous Quantification of Brassinolide and Other Plant Hormones Involved in Abiotic Stresses

    OpenAIRE

    Kasote, Deepak M.; Ghosh, Ritesh; Chung, Jun Young; Kim, Jonggeun; Bae, Inhwan; Bae, Hanhong

    2016-01-01

    Plant hormones are the key regulators of adaptive stress response. Abiotic stresses such as drought and salt are known to affect the growth and productivity of plants. It is well known that the levels of plant hormones such as zeatin (ZA), abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), and brassinolide (BR) fluctuate upon abiotic stress exposure. At present, there is not any single suitable liquid chromatography-mass spectrometry (LC-MS) method for simultaneous analysis of BR a...

  2. Phase Behavior of Mixtures of Ionic Liquids and Organic Solvents

    DEFF Research Database (Denmark)

    Abildskov, Jens; Ellegaard, Martin Dela; O’Connell, J.P.

    2010-01-01

    A corresponding-states form of the generalized van der Waals equation, previously developed for mixtures of an ionic liquid and a supercritical solute, is here extended to mixtures including an ionic liquid and a solvent (water or organic). Group contributions to characteristic parameters...

  3. Chiral Separation of Naproxen with Immobilized Liquid Phases

    NARCIS (Netherlands)

    Corderi Gandara, Sandra; Vitasari, C.R.; Gramblicka, M.; Giard, T.; Schuur, Boelo

    2016-01-01

    The use of solvent-impregnated resins (SIRs) as a hybrid technology between liquid extraction and adsorption was investigated for the enantioseparation of naproxen. A chiral recognition system from the enantioselective liquid–liquid extraction from the literature was taken as a starting point,

  4. Ultrapreconcentration and determination of organophosphorus pesticides in water by solid-phase extraction combined with dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Chen, Junhua; Zhou, Guangming; Deng, Yongli; Cheng, Hongmei; Shen, Jie; Gao, Yi; Peng, Guilong

    2016-01-01

    Solid-phase extraction coupled with dispersive liquid-liquid microextraction was developed as an ultra-preconcentration method for the determination of four organophosphorus pesticides (isocarbophos, parathion-methyl, triazophos and fenitrothion) in water samples. The analytes considered in this study were rapidly extracted and concentrated from large volumes of aqueous solutions (100 mL) by solid-phase extraction coupled with dispersive liquid-liquid microextraction and then analyzed using high performance liquid chromatography. Experimental variables including type and volume of elution solvent, volume and flow rate of sample solution, salt concentration, type and volume of extraction solvent and sample solution pH were investigated for the solid-phase extraction coupled with dispersive liquid-liquid microextraction with these analytes, and the best results were obtained using methanol as eluent and ethylene chloride as extraction solvent. Under the optimal conditions, an exhaustive extraction for four analytes (recoveries >86.9%) and high enrichment factors were attained. The limits of detection were between 0.021 and 0.15 μg/L. The relative standard deviations for 0.5 μg/L of the pesticides in water were in the range of 1.9-6.8% (n = 5). The proposed strategy offered the advantages of simple operation, high enrichment factor and sensitivity and was successfully applied to the determination of four organophosphorus pesticides in water samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Dielectric spectroscopy of isotropic liquids and liquid crystal phases with dispersed graphene oxide

    Science.gov (United States)

    Al-Zangana, Shakhawan; Iliut, Maria; Boran, Gökçen; Turner, Michael; Vijayaraghavan, Aravind; Dierking, Ingo

    2016-08-01

    Graphene oxide (GO) flakes of different sizes were prepared and dispersed in isotropic and nematic (anisotropic) fluid media. The dielectric relaxation behaviour of GO-dispersions was examined for a wide temperature (25-60 oC) and frequency range (100 Hz-2 MHz). The mixtures containing GO flakes exhibited varying dielectric relaxation processes, depending on the size of the flakes and the elastic properties of the dispersant fluid. Relaxation frequencies of the GO doped isotropic media, such as isopropanol IPA, were observed to be much lower than the GO doped thermotropic nematic medium 5CB. It is anticipated that the slow relaxation frequencies (~10 kHz) could be resulting from the relaxation modes of the GO flakes while the fast relaxation frequencies (~100 kHz) could indicate strongly slowed down molecular modes of the nematogenic molecules, which are anchored to the GO flakes via dispersion interactions. The relaxation frequencies decreased as the size of the GO flakes in the isotropic solvent was increased. Polarizing microscopy showed that GO flakes with a mean diameter of 10 μm, dispersed in water, formed a lyotropic nematic liquid crystal phase. This lyotropic nematic exhibited the slowest dielectric relaxation process, with relaxation frequencies in the order of 2 kHz, as compared to the GO-isotropic suspension and the GO-doped 5CB.

  6. Liquid Phase Sintering of Boron-Containing Powder Metallurgy Steel with Chromium and Carbon

    Science.gov (United States)

    Wu, Ming-Wei; Fan, Yu-Chi; Huang, Her-Yueh; Cai, Wen-Zhang

    2015-11-01

    Liquid phase sintering is an effective method to improve the densification of powder metallurgy materials. Boron is an excellent alloying element for liquid phase sintering of Fe-based materials. However, the roles of chromium and carbon, and particularly that of the former, on liquid phase sintering are still undetermined. This study demonstrated the effects of chromium and carbon on the microstructure, elemental distribution, boride structure, liquid formation, and densification of Fe-B-Cr and Fe-B-Cr-C steels during liquid phase sintering. The results showed that steels with 0.5 wt pct C densify faster than those without 0.5 wt pct C. Moreover, although only one liquid phase forms in Fe-B-Cr steel, adding 0.5 wt pct C reduces the formation temperature of the liquid phase by about 50 K (°C) and facilitates the formation of an additional liquid, resulting in better densification at 1473 K (1200 °C). In both Fe-B-Cr and Fe-B-Cr-C steels, increasing the chromium content from 1.5 to 3 wt pct raises the temperature of liquid formation by about 10 K (°C). Thermodynamic simulations and experimental results demonstrated that carbon atoms dissolved in austenite facilitate the eutectic reaction and reduce the formation temperature of the liquid phase. In contrast, both chromium and molybdenum atoms dissolved in austenite delay the eutectic reaction. Furthermore, the 3Cr-0.5Mo additive in the Fe-0.4B steel does not change the typical boride structure of M2B. With the addition of 0.5 wt pct C, the crystal structure is completely transformed from M2B boride to M3(B,C) boro-carbide.

  7. New methods and materials for solid phase extraction and high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Dumont, Philip John [Iowa State Univ., Ames, IA (United States)

    1996-04-23

    This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

  8. Critical fluctuations in liquid He/sup 3/: Stabilization of the Anderson-Morel phase

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, A.I.

    1979-05-20

    The equations for the renormalized group, which describe the superfluid phase transitions in liquid He/sup 3/, are derived and solved (on the computer). It is shown that the interaction of the critical fluctuations of the order parameter increases the region corresponding to phase A in the phase diagram of He/sup 3/.

  9. Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

    National Research Council Canada - National Science Library

    A. Zuend; C. Marcolli; T. Peter; J. H. Seinfeld

    2010-01-01

    .... Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle...

  10. Applications of liquid-phase microextraction techniques in natural product analysis: a review.

    Science.gov (United States)

    Yan, Yunyan; Chen, Xuan; Hu, Shuang; Bai, Xiaohong

    2014-11-14

    Over the last years, liquid-phase microextraction (LPME) as a simple, rapid, practical and effective sample-preparation technique, coupled with various instrumental analytical methods, has been increasingly and widely used to research and determine trace or ultra-micro-levels of both inorganic and organic analytes from different matrix-complex samples. In this review, different kinds of LPMEs such as single drop liquid-phase microextraction, dispersive liquid-liquid microextraction, and hollow fibre liquid-phase microextraction are summarized and recent applications of LPMEs in trace compounds in vivo and in vitro from different natural product matrice analysis such as tea, vegetables, seeds, herbs, and galenical are also discussed. Finally, future developments and applications of LPMEs in complex sample analysis are prospected. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Docetaxel and ketoconazole in advanced hormone-refractory prostate carcinoma: a phase I and pharmacokinetic study.

    Science.gov (United States)

    Van Veldhuizen, Peter J; Reed, Gregory; Aggarwal, Arvind; Baranda, Joaquina; Zulfiqar, Muhammad; Williamson, Stephen

    2003-11-01

    Docetaxel has significant single-agent activity in patients with prostate carcinoma, and ketoconazole has activity as a second-line hormonal agent. In vitro, ketoconazole exhibits synergy with several chemotherapeutic agents. A potential drug interaction exists, however, because both docetaxel and ketoconazole are metabolized hepatically by the cytochrome p450 system (CYP3A4). The authors performed a Phase I study and a pharmacokinetic study evaluating the both tolerability of a docetaxel/ketoconazole combination as well as this potential drug interaction. For all initial patients, docetaxel was administered intravenously at a dose of 55 mg/m(2) over 1 hour every 21 days. Starting on Day 8 after their first docetaxel dose, cohorts of at least 3-5 new patients were enrolled to receive escalating doses of ketoconazole. When the maximally tolerated dose (MTD) of ketoconazole was reached, the subsequent cohort of patients received an escalating dose of docetaxel. Pharmacokinetic studies were performed after docetaxel infusions on Day 1 (prior to ketoconazole) and Day 22 (after starting ketoconazole). Twenty-six patients were enrolled and completed at least 2 cycles of treatment. The MTD was ketoconazole 400 mg twice daily and docetaxel 55 mg/m(2). Dose-limiting toxicities included neutropenia and fatigue. Ketoconazole did not cause a consistent effect on docetaxel pharmacokinetics, although there was significant intrapatient and interpatient variability in serum levels. The recommended Phase II dose for this combination is ketoconazole 400 mg twice daily and docetaxel 55 mg/m(2) every 21 days.

  12. Liquid-liquid phase equilibria for ternary systems of several polyethers with NaCl and H2O

    NARCIS (Netherlands)

    Milosevic, M.; Staal, K.J.J.; Schuur, Boelo; de Haan, A.B.

    2014-01-01

    Liquid–liquid extraction using polymers followed by induced phase separation is a potential energy reducing technology for water–salt separation. Ternary equilibrium data have been determined and reported for the (block co)poly ethers–sodium chloride–water systems at two different temperatures at

  13. Vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria calculations for polystyrene plus methyleyclohexane and polystyrene plus cyclohexane solutions

    DEFF Research Database (Denmark)

    Wilczura-Wachnik, H.; Jonsdottir, Svava Osk

    2006-01-01

    This paper presents the vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria predictions for polystyrene in two theta solvents: cyclohexane and methylcyclohexane. VLE calculations were performed with the Elbro free volume method and a modified version of the PC-SAFT method, as well...... as with three UNIFAC type group contribution models: Entropic Free Volume + UNIFAC VLE 1 coeff., Entropic Free Volume + UNIFAC VLE 2coeff., and Oishi-Prausnitz + UNIFAC VLE 2coeff. Solvent activities were calculated for the polystyrene + cyclohexane and polystyrene + methylcyclohcxane solutions, and compared...

  14. Expanding the Applicability of Poly(Ionic Liquids) in Solid Phase Microextraction: Pyrrolidinium Coatings

    National Research Council Canada - National Science Library

    David J. S. Patinha; Liliana C. Tomé; Mehmet Isik; David Mecerreyes; Armando J. D. Silvestre; Isabel M. Marrucho

    2017-01-01

    Crosslinked pyrrolidinium-based poly(ionic liquids) (Pyrr-PILs) were synthesized through a fast, simple, and solventless photopolymerization scheme, and tested as solid phase microextraction (SPME) sorbents...

  15. HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC SEPARATION OF THE ENANTIOMERS OF ORGANOPHOSPHORUS PESTICIDES ON POLYSACCHARIDE CHIRAL STATIONARY PHASES

    Science.gov (United States)

    High-performance liquid chromatographic separation of the individual enantiomers of 12 organophosphorus pesticides (OPs) was obtained on polysaccharide enantioselective HPLC columns using alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, fonofos, fenamiph...

  16. Changes in apple liquid phase concentration throughout equilibrium in osmotic dehydration.

    Science.gov (United States)

    Barat, J M; Barrera, C; Frías, J M; Fito, P

    2007-03-01

    Previous results on apple tissue equilibration during osmotic dehydration showed that, at very long processing times, the solute concentrations of the fruit liquid phase and the osmotic solution were the same. In the present study, changes in apple liquid phase composition throughout equilibrium in osmotic dehydration were analyzed and modeled. Results showed that, by the time osmosed samples reached the maximum weight and volume loss, solute concentration of the fruit liquid phase was higher than that of the osmotic solution. The reported overconcentration could be explained in terms of the apple structure shrinkage that occurred during the osmotic dehydration with highly concentrated osmotic solutions due to the elastic response of the food structure to the loss of water and intake of solutes. The fruit liquid phase overconcentration rate was observed to depend on the concentration of the osmotic solution, the processing temperature, the sample size, and shape of the cellular tissue.

  17. On the implications of aerosol liquid water and phase separation for organic aerosol mass

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset contains data presented in the figures of the paper "On the implications of aerosol liquid water and phase separation for organic aerosol mass"...

  18. PROCESSES OF LIQUID-PHASE RECOVERY OF SCALE IN ROTATIONAL FURNACE

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2012-01-01

    Full Text Available The data, enabling to establish peculiarities and distinction of liquid-phase reduction of oxides in rotation furnaces, are received as a result of laboratory and field observations.

  19. Light-Weight, Low-Cost, Single-Phase, Liquid-Cooled Cold Plate (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S.

    2013-07-01

    This presentation, 'Light-Weight, Low-Cost, Single-Phase Liquid-Cooled Cold Plate,' directly addresses program goals of increased power density, specific power, and lower cost of power electronics components through improved thermal management.

  20. Light-Weight, Single-Phase, Liquid-Cooled Cold Plate (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S.

    2013-07-01

    This presentation, 'Light-Weight, Low-Cost, Single-Phase Liquid-Cooled Cold Plate,' directly addresses program goals of increased power density, specific power, and lower cost of power electronics components through improved thermal management.

  1. Gallium-rich Pd-Ga phases as supported liquid metal catalysts

    Science.gov (United States)

    Taccardi, N.; Grabau, M.; Debuschewitz, J.; Distaso, M.; Brandl, M.; Hock, R.; Maier, F.; Papp, C.; Erhard, J.; Neiss, C.; Peukert, W.; Görling, A.; Steinrück, H.-P.; Wasserscheid, P.

    2017-09-01

    A strategy to develop improved catalysts is to create systems that merge the advantages of heterogeneous and molecular catalysis. One such system involves supported liquid-phase catalysts, which feature a molecularly defined, catalytically active liquid film/droplet layer adsorbed on a porous solid support. In the past decade, this concept has also been extended to supported ionic liquid-phase catalysts. Here we develop this idea further and describe supported catalytically active liquid metal solutions (SCALMS). We report a liquid mixture of gallium and palladium deposited on porous glass that forms an active catalyst for alkane dehydrogenation that is resistant to coke formation and is thus highly stable. X-ray diffraction and X-ray photoelectron spectroscopy, supported by theoretical calculations, confirm the liquid state of the catalytic phase under the reaction conditions. Unlike traditional heterogeneous catalysts, the supported liquid metal reported here is highly dynamic and catalysis does not proceed at the surface of the metal nanoparticles, but presumably at homogeneously distributed metal atoms at the surface of a liquid metallic phase.

  2. Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

    Science.gov (United States)

    O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

    2009-01-01

    Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

  3. Active role of the liquid phase of developer in revealing surface flaws by capillary methods

    Energy Technology Data Exchange (ETDEWEB)

    Prokhorenko, P.P.; Dezhkunov, N.V.; Stoicheva, I.V.

    1988-08-01

    The article investigates the interaction of two chemically nonreacting liquids after they have been brought into contact with each other in a capillary. It is established that the liquid phase of the developer is not only a passive carrier of the developing component but also exerts an active influence on the process of development, and consequently, on the detectability of flaws.

  4. Evaluation of mercury in liquid waste processing facilities - Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    Jain, V. [Savannah River Site (SRS), Aiken, SC (United States); Occhipinti, J. E. [Savannah River Site (SRS), Aiken, SC (United States); Shah, H. [Savannah River Site (SRS), Aiken, SC (United States); Wilmarth, W. R. [Savannah River Site (SRS), Aiken, SC (United States); Edwards, R. E. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-07-01

    This report provides a summary of Phase I activities conducted to support an Integrated Evaluation of Mercury in Liquid Waste System (LWS) Processing Facilities. Phase I activities included a review and assessment of the liquid waste inventory and chemical processing behavior of mercury using a system by system review methodology approach. Gaps in understanding mercury behavior as well as action items from the structured reviews are being tracked. 64% of the gaps and actions have been resolved.

  5. Evaluation of Mercury in Liquid Waste Processing Facilities - Phase I Report

    Energy Technology Data Exchange (ETDEWEB)

    Jain, V. [Savannah River Site (SRS), Aiken, SC (United States); Occhipinti, J. [Savannah River Site (SRS), Aiken, SC (United States); Shah, H. [Savannah River Site (SRS), Aiken, SC (United States); Wilmarth, B. [Savannah River Site (SRS), Aiken, SC (United States); Edwards, R. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-07-01

    This report provides a summary of Phase I activities conducted to support an Integrated Evaluation of Mercury in Liquid Waste System (LWS) Processing Facilities. Phase I activities included a review and assessment of the liquid waste inventory and chemical processing behavior of mercury using a system by system review methodology approach. Gaps in understanding mercury behavior as well as action items from the structured reviews are being tracked. 64% of the gaps and actions have been resolved.

  6. V-structures of ethylene glycol and monoethanolamine in the temperature range of the liquid phase

    Science.gov (United States)

    Balabaev, N. K.; Rodnikova, M. N.; Solonina, I. A.; Shirokova, E. V.; Sirotkin, D. A.

    2017-01-01

    Vibration-averaged V-structures for liquid ethylene glycol (EG) and monoethanolamine (MEA) are found in the temperature range of the solvents' liquid phase by means of molecular dynamics. The obtained V-structures' characteristics are compared to X-ray diffraction data on the crystalline phases of these compounds. Good agreement between theoretical and experimental data is observed. The V-structures are compared to that of water.

  7. Liquid phase oxidation via heterogeneous catalysis organic synthesis and industrial applications

    CERN Document Server

    Clerici, Mario G

    2013-01-01

    Sets the stage for environmentally friendly industrial organic syntheses From basic principles to new and emerging industrial applications, this book offers comprehensive coverage of heterogeneous liquid-phase selective oxidation catalysis. It fully examines the synthesis, characterization, and application of catalytic materials for environmentally friendly organic syntheses. Readers will find coverage of all the important classes of catalysts, with an emphasis on their stability and reusability. Liquid Phase Oxidation via Heterogeneous Catalysis features contributions from an internation

  8. Cation-exchange solid-phase and liquid-liquid extraction for the ...

    African Journals Online (AJOL)

    An existing liquid-liquid extraction (LLE) method was improved in terms of recoveries obtained, by using ethyl acetate as extractant. For pure standards of the khat alkaloids, recoveries ranged from 83 to 97%. Preconcentration, using a Genevac evaporator after the addition of acidified water to the sample, restricted analyte ...

  9. Metastable phase selection from undercooled Zr 77 Rh 23 liquid alloys

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M. L.; Gibbons, P. C.; Vogt, A. J.; Kelton, K. F.

    2017-11-01

    From measurements of X-ray and neutron scattering of electrostatically levitated Zr77Rh23 liquids, a variety of metastable crystallization behavior was observed. The metastable phase selection in deeply undercooled liquid droplets is characterized and their crystallization pathways discussed. A metastable phase previously identified as a primary devitrification product from the metallic glass formed when undercooling was maximized to near the hypercooling limit. The direct formation of α–Zr and the equilibrium C16 phase as well as a newly discovered Zr5Rh3 (Mg5Si3-type) phase are also reported.

  10. First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation

    DEFF Research Database (Denmark)

    Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter

    2006-01-01

    A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.......A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation....

  11. Liquid chromatography-tandem mass spectrometry analysis of human adrenal vein corticosteroids before and after adrenocorticotropic hormone stimulation.

    Science.gov (United States)

    Nakamura, Yasuhiro; Rege, Juilee; Satoh, Fumitoshi; Morimoto, Ryo; Kennedy, Michael R; Ahlem, Clarence N; Honma, Seijiro; Sasano, Hironobu; Rainey, William E

    2012-06-01

    Although steroid hormones produced by the adrenal gland play critical roles in human physiology, a detailed quantitative analysis of the steroid products has not been reported. The current study uses a single methodology (liquid chromatography-tandem mass spectrometry, LC-MS/MS) to quantify ten corticosteroids in adrenal vein (AV) samples pre- and post-adrenocorticotropic hormone (ACTH) stimulation. Three men and six women with a diagnosis of an adrenal aldosterone-producing adenoma (APA) were included in the study. Serum was collected from the iliac vein (IV) and the AV contralateral to the diseased adrenal. Samples were collected, before and after administration of ACTH. LC-MS/MS was then used to quantify serum concentrations of unconjugated corticosteroids and their precursors. Prior to ACTH stimulation, the four most abundant steroids in AV were cortisol (90%), cortisone (4%), corticosterone (3%) and 11-deoxycortisol (0.8%). Post-ACTH administration, cortisol remained the major adrenal product (79%); however, corticosterone became the second most abundantly produced adrenal steroid (11%) followed by pregnenolone (2.5%) and 17α-hydroxypregnenolone (2%). ACTH significantly increased the absolute adrenal output of all ten corticosteroids measured (P corticosteroids in peripheral and AV serum samples under pre- and post-ACTH stimulation. This study demonstrates the primary adrenal steroid products and their response to ACTH. © 2012 Blackwell Publishing Ltd.

  12. Dicationic imidazolium ionic liquid modified silica as a novel reversed-phase/anion-exchange mixed-mode stationary phase for high-performance liquid chromatography.

    Science.gov (United States)

    Sun, Min; Feng, Juanjuan; Wang, Xiaojiao; Duan, Huimin; Li, Leilei; Luo, Chuannan

    2014-08-01

    A dicationic imidazolium ionic liquid modified silica stationary phase was prepared and evaluated by reversed-phase/anion-exchange mixed-mode chromatography. Model compounds (polycyclic aromatic hydrocarbons and anilines) were separated well on the column by reversed-phase chromatography; inorganic anions (bromate, bromide, nitrate, iodide, and thiocyanate), and organic anions (p-aminobenzoic acid, p-anilinesulfonic acid, sodium benzoate, pathalic acid, and salicylic acid) were also separated individually by anion-exchange chromatography. Based on the multiple sites of the stationary phase, the column could separate 14 solutes containing the above series of analytes in one run. The dicationic imidazolium ionic liquid modified silica can interact with hydrophobic analytes by the hydrophobic C6 chain; it can enhance selectivity to aromatic compounds by imidazolium groups; and it also provided anion-exchange and electrostatic interactions with ionic solutes. Compared with a monocationic ionic liquid functionalized stationary phase, the new stationary phase represented enhanced selectivity owing to more interaction sites. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Modeling the gas-particle partitioning of secondary organic aerosol: the importance of liquid-liquid phase separation

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2012-05-01

    Full Text Available The partitioning of semivolatile organic compounds between the gas phase and aerosol particles is an important source of secondary organic aerosol (SOA. Gas-particle partitioning of organic and inorganic species is influenced by the physical state and water content of aerosols, and therefore ambient relative humidity (RH, as well as temperature and organic loading levels. We introduce a novel combination of the thermodynamic models AIOMFAC (for liquid mixture non-ideality and EVAPORATION (for pure compound vapor pressures with oxidation product information from the Master Chemical Mechanism (MCM for the computation of gas-particle partitioning of organic compounds and water. The presence and impact of a liquid-liquid phase separation in the condensed phase is calculated as a function of variations in relative humidity, organic loading levels, and associated changes in aerosol composition. We show that a complex system of water, ammonium sulfate, and SOA from the ozonolysis of α-pinene exhibits liquid-liquid phase separation over a wide range of relative humidities (simulated from 30% to 99% RH. Since fully coupled phase separation and gas-particle partitioning calculations are computationally expensive, several simplified model approaches are tested with regard to computational costs and accuracy of predictions compared to the benchmark calculation. It is shown that forcing a liquid one-phase aerosol with or without consideration of non-ideal mixing bears the potential for vastly incorrect partitioning predictions. Assuming an ideal mixture leads to substantial overestimation of the particulate organic mass, by more than 100% at RH values of 80% and by more than 200% at RH values of 95%. Moreover, the simplified one-phase cases stress two key points for accurate gas-particle partitioning calculations: (1 non-ideality in the condensed phase needs to be considered and (2 liquid-liquid phase separation is a consequence of considerable deviations

  14. Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    B. D. Castro

    2005-09-01

    Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.

  15. Cloud Point and Liquid-Liquid Equilibrium Behavior of Thermosensitive Polymer L61 and Salt Aqueous Two-Phase System.

    Science.gov (United States)

    Rao, Wenwei; Wang, Yun; Han, Juan; Wang, Lei; Chen, Tong; Liu, Yan; Ni, Liang

    2015-06-25

    The cloud point of thermosensitive triblock polymer L61, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), was determined in the presence of various electrolytes (K2HPO4, (NH4)3C6H5O7, and K3C6H5O7). The cloud point of L61 was lowered by the addition of electrolytes, and the cloud point of L61 decreased linearly with increasing electrolyte concentration. The efficacy of electrolytes on reducing cloud point followed the order: K3C6H5O7 > (NH4)3C6H5O7 > K2HPO4. With the increase in salt concentration, aqueous two-phase systems exhibited a phase inversion. In addition, increasing the temperature reduced the concentration of salt needed that could promote phase inversion. The phase diagrams and liquid-liquid equilibrium data of the L61-K2HPO4/(NH4)3C6H5O7/K3C6H5O7 aqueous two-phase systems (before the phase inversion but also after phase inversion) were determined at T = (25, 30, and 35) °C. Phase diagrams of aqueous two-phase systems were fitted to a four-parameter empirical nonlinear expression. Moreover, the slopes of the tie-lines and the area of two-phase region in the diagram have a tendency to rise with increasing temperature. The capacity of different salts to induce aqueous two-phase system formation was the same order as the ability of salts to reduce the cloud point.

  16. Lipase inhibition and hormonal status, body composition and gastrointestinal processing of a liquid high-fat mixed meal in moderately obese subjects.

    NARCIS (Netherlands)

    Drent, M.L.; Popp-Snijders, C.; Adèr, H.J.; Jansen, J.B.M.J.; van der Veen, E.A.

    1995-01-01

    DRENT, MADELEINE L, CORRIE POPP‐SNIJDERS, HERMAN J ADER, JAN BMJ JANSEN AND EDUARD A VAN DER VEEN. Lipase inhibition and hormonal status, body composition and gastrointestinal processing of a liquid high‐fat mixed meal in moderately obese subjects. Obes Res. The effect of Orlistat, a lipase

  17. Screening and confirmation criteria for hormone residue analysis using liquid chromatography accurate mass time-of-flight, Fourier transform ion cyclotron resonance and orbitrap mass spectrometry techniques

    NARCIS (Netherlands)

    Nielen, M.W.F.; Engelen, M.C. van; Zuiderent, R.; Ramaker, R.

    2007-01-01

    An emerging trend is recognised in hormone and veterinary drug residue analysis from liquid chromatography tandem mass spectrometry (LC/MS/MS) based screening and confirmation towards accurate mass alternatives such as LC coupled with time-of-flight (TOF), Fourier transform ion cyclotron resonance

  18. Preparation and Characterization of Silicone Liquid Core/Polymer Shell Microcapsules via Internal Phase Separation

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Kostrzewska, Malgorzata; Ma, Baoguang

    2014-01-01

    Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesisedthrough the controlled phase separation. The dispersed silicone phase consisted of the shellpolymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent(methylhydrosiloxane dimethylsil......Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesisedthrough the controlled phase separation. The dispersed silicone phase consisted of the shellpolymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent......(methylhydrosiloxane dimethylsiloxane) for thePMMA. The morphology of the PMMA micro-capsules was investigated by ATR-FTIR and byoptical microscopy. Microcapsules were preparedwith different emulsifiers and different concen-trations of acetone and PMMA in the oil phase.The thermal stability of the PMMA microcapsuleand the content...... of the silicone oil core wereassessed by TGA.1H-NMR spectroscopy and anextraction method were also used to determine the content of the silicone liquid core in the microcapsules....

  19. Phase diagrams of mixtures of a polymer and a cholesteric liquid crystal under an external field.

    Science.gov (United States)

    Matsuyama, Akihiko

    2014-11-14

    We present a mean field theory to describe phase behaviors in mixtures of a polymer and a cholesteric liquid crystal under an external magnetic or electric field. Taking into account a chiral coupling between a polymer and a liquid crystal under the external field, we examine twist-untwist phase transitions and phase separations in the mixtures. It is found that a cholesteric-nematic phase transition can be induced by not only the external field but also concentration and temperature. Depending on the strength of the external field, we predict cholesteric-paranematic (Ch+pN), nematic-paranematic (N+pN), cholesteric-nematic (Ch+N) phase separations, etc., on the temperature-concentration plane. We also discuss mixtures of a non-chiral nematic liquid crystal and a chiral dopant.

  20. Diffusion-Driven Dissolution or Growth of a Liquid Drop Embedded in a Continuous Phase of Another Liquid via Phase-Field Ternary Mixture Model.

    Science.gov (United States)

    Lamorgese, Andrea; Mauri, Roberto

    2017-11-14

    We simulate the diffusion-driven dissolution or growth of a single-component (resp. two-component) drop embedded in a continuous phase of a binary (resp. single-component) liquid. Our theoretical approach follows a standard diffuse-interface model of partially miscible ternary liquid mixtures, which is based on a regular solution model assumption together with a Flory-Huggins and Cahn-Hilliard representation of the excess and nonlocal components of the Gibbs free energy of mixing. Based on 2D simulation results, we show that for a single-component drop embedded in a continuous phase of a binary liquid (which is highly miscible with either one component of the continuous phase but essentially immiscible with the other) the size of the drop can either shrink to zero or reach a stationary value, depending on whether the global composition of the mixture is within the one-phase region or the unstable range of the phase diagram. On the other hand, for an isolated two-component drop embedded in a continuous phase of a single-component liquid (which is essentially immiscible with either one component of the drop but miscible with the other) the size of the drop can either grow or shrink and, in particular, it will eventually go to zero if the global composition of the mixture is within the one-phase region; otherwise, for system locations in the unstable range the size of the drop tends to a constant value as the composition within the drop reaches its final equilibrium value.

  1. Energy of formation for AgIn liquid binary alloys along the line of phase separation

    CERN Document Server

    Bhuiyan, G M; Ziauddin-Ahmed, A Z

    2003-01-01

    We have investigated the energy of formation for AgIn liquid binary alloys along the solid-liquid phase separation line. A microscopic theory based on the first order perturbation has been applied. The interionic interaction and a reference liquid are the fundamental components of the theory. These are described by a local pseudopotential and the hard sphere liquids, respectively. The results of calculations reveal a characteristic feature that the energy of formation becomes minimum at the equiatomic composition, and thus indicates maximal mix-ability at this concentration. The energy of formation at a particular thermodynamic state that is at T 1173 K predicts the experimental trends fairly well.

  2. Influence of the Physical Properties of Liquids and Diameter of Bubble on the Formation of Liquid Column at the Interface of Two Liquid Phases by the Rising Bubble

    Science.gov (United States)

    Tanno, Masanori; Liu, Jiang; Gao, Xu; Kim, Sun-Joong; Ueda, Shigeru; Kitamura, Shin-ya

    2017-10-01

    The formation of metal emulsion in a steel-making process enhances the reaction between metal and slag. A part of the metal emulsion is formed by a bubble passing through the interface between the metal and slag phases. In a previous study, it was determined that the formation of metal column by the bubble is related to the formation of metal droplets. In this research, the effects of bubble particle size, interfacial tension, viscosity of upper layer, and lower layer density on the formation of lower liquid column were investigated. In order to conduct an in situ observation of gas and liquid behaviors, aqueous solution and silicon oil systems were employed. It was determined that a narrow and elongated column forms liquid droplets in the upper liquid layer and contributes to the formation of droplets. The height of the column and the volume of droplets increase with the increase in bubble size. The influence of interfacial tension of the two liquid phases on the column height and the formation of droplet is slight. The height of the formed column decreases with the increase in the density of lower liquid.

  3. Influence of the Physical Properties of Liquids and Diameter of Bubble on the Formation of Liquid Column at the Interface of Two Liquid Phases by the Rising Bubble

    Science.gov (United States)

    Tanno, Masanori; Liu, Jiang; Gao, Xu; Kim, Sun-Joong; Ueda, Shigeru; Kitamura, Shin-ya

    2017-12-01

    The formation of metal emulsion in a steel-making process enhances the reaction between metal and slag. A part of the metal emulsion is formed by a bubble passing through the interface between the metal and slag phases. In a previous study, it was determined that the formation of metal column by the bubble is related to the formation of metal droplets. In this research, the effects of bubble particle size, interfacial tension, viscosity of upper layer, and lower layer density on the formation of lower liquid column were investigated. In order to conduct an in situ observation of gas and liquid behaviors, aqueous solution and silicon oil systems were employed. It was determined that a narrow and elongated column forms liquid droplets in the upper liquid layer and contributes to the formation of droplets. The height of the column and the volume of droplets increase with the increase in bubble size. The influence of interfacial tension of the two liquid phases on the column height and the formation of droplet is slight. The height of the formed column decreases with the increase in the density of lower liquid.

  4. Insight into solid-liquid phase transfer catalyzed synthesis of ...

    Indian Academy of Sciences (India)

    Ganapati D Yadav

    2017-11-16

    Nov 16, 2017 ... C. Simple isolation process was employed to recover the product from the reaction mixture. A reaction mechanism was proposed and new kinetic model developed involving one liquid and two solid co-products. The activation energy for the reaction was calculated. This is the first example of its kind being ...

  5. Liquid-Phase Electrical Discharges: Fundamental Mechanisms and Applications

    Science.gov (United States)

    Franclemont, Joshua

    The increased demand in alternative energy in recent decades has generated significant interest in cleaner fuel sources including hydrogen and syngas (hydrogen and carbon monoxide). Hydrogen and syngas are both primarily produced through the steam reforming of hydrocarbons, specifically natural gas. Although other processes are known, the cheapest source of these fuels is currently through the heating of natural gas in the presence of steam and a catalyst. However, due to the emissions associated with the steam reforming of natural gas and the lack of low cost, efficient, and reliable onboard hydrogen storage technologies for fuel cell powered vehicles, attention has been focused on plasma-assisted reforming of hydrocarbons. Plasma processes can be implemented onboard and are able to directly reform liquid hydrocarbons and alcohols without external heating or catalysts. In addition to hydrogen and syngas, the plasma-assisted reforming of hydrocarbons and alcohols offers other desirable products such as C2 gases (ethane, ethylene, and acetylene), methanol and ethanol. The primary goal of this study is to investigate the fundamental chemical reactions occurring during plasma-assisted reforming of liquid hydrocarbons and alcohols using streamer-like pulsed electrical discharges. Due to the relatively unexplored field of chemical reactions in liquid plasmas, the focus of this study is on elucidating chemical pathways responsible for the formation of hydrogen, syngas, and other products during the direct reforming of liquid methanol, glycerol, and pentane as model species.

  6. On some liquid crystalline phases exhibited by compounds made of ...

    Indian Academy of Sciences (India)

    Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmA db liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bi- layer smectic structure formed by the rods. We also describe unusual growth patterns obtained when.

  7. Student Understanding of Liquid-Vapor Phase Equilibrium

    Science.gov (United States)

    Boudreaux, Andrew; Campbell, Craig

    2012-01-01

    Student understanding of the equilibrium coexistence of a liquid and its vapor was the subject of an extended investigation. Written assessment questions were administered to undergraduates enrolled in introductory physics and chemistry courses. Responses have been analyzed to document conceptual and reasoning difficulties in sufficient detail to…

  8. Effect of smoking on acute phase reactants, stress hormone responses and vitamin C in pulmonary tuberculosis.

    Science.gov (United States)

    Opolot, John O; Theron, Annette J; MacPhail, Patrick; Feldman, Charles; Anderson, Ronald

    2017-06-01

    Chronic inflammation, possibly exacerbated by cigarette smoking, is considered to be the primary cause of pulmonary damage in patients with tuberculosis (TB). However, the mechanisms which underpin these harmful inflammatory responses, have not been well documented. The current study was undertaken to determine possible associations between systemic biomarkers of inflammation (acute phase reactants, stress hormones, leukocyte vitamin C) and smoking status in patients (n=71, 20 smokers) with newly-diagnosed pulmonary TB presenting at a tertiary hospital, Johannesburg, South Africa. Plasma concentrations of C-reactive protein (CRP), ferritin, cortisol, epinephrine, norepinephrine, dopamine and leukocyte vitamin C were measured using a combination of immunonephelometric, radioimmunoassay, immunochromatographic and spectrophotometric procedures. Demographic, clinical and laboratory data was captured and analysed by parametric and non-parametric analyses where appropriate. Smokers were predominantly males (Psignificantly lower body mass index (Psignificance (Pcortisol and norepinephrine were comparable to those of non-smokers, as were radiographic changes and clinical indices of disease activity. Cigarette smoking is associated with an exaggerated systemic inflammatory response in pulmonary TB in the setting of decreased concentrations of leukocyte vitamin C. Although no significant associations with radiographic changes and most clinical indices of disease activity were evident on presentation, these pro-inflammatory interactions may have prognostic significance.

  9. Phase equilibria and modeling of ammonium ionic liquid, C2NTf2, solutions.

    Science.gov (United States)

    Domańska, Urszula; Marciniak, Andrzej; Królikowski, Marek

    2008-01-31

    Novel quaternary ammonium ionic liquid, ethyl(2-hydroxyethyl)dimethylammonium bis(trifluomethylsulfonyl)imide (C2NTf2), has been prepared from N,N-dimethylethanolamine as a substrate. The paper includes a specific basic characterization of the synthesized compound by NMR and the basic thermophysical properties: the melting point, enthalpy of fusion, enthalpy of solid-solid phase transition, glass transition determined by the differential scanning calorimetry (DSC), temperature of decomposition, and water content. The density of the new compound was measured. The solid-liquid or liquid-liquid phase equilibria of binary mixtures containing {C2NTf2+water or an alcohol (propan-1-ol, butan-1-ol, hexan-1-ol, octan-1-ol, decan-1-ol), aromatic hydrocarbons (benzene, toluene), aliphatic hydrocarbons (n-hexane, n-octane), dimethylsulfoxide (DMSO), or tetrahydrofuran (THF)} have been measured by a dynamic method in a wide range of temperatures from 230 to 430 K. These data were correlated by means of the nonrandom two-liquid (NRTL) equation utilizing temperature-dependent parameters derived from the solid-liquid or liquid-liquid equilibrium. From the solubility results, the negative value of the partition coefficient of ionic liquid in binary system octan-1-ol/water (log P) at 298.15 K has been calculated.

  10. Isomorphs in the phase diagram of a model liquid without inverse power law repulsion

    DEFF Research Database (Denmark)

    Veldhorst, Arnold Adriaan; Bøhling, Lasse; Dyre, J. C.

    2012-01-01

    the dynamics of the viscous Buckingham liquid is mimicked by a corresponding model with purely repulsive inverse-power-law interactions. The results presented here closely resemble earlier results for Lennard-Jones type liquids, demonstrating that the existence of strong correlations and isomorphs does......It is demonstrated by molecular dynamics simulations that liquids interacting via the Buckingham potential are strongly correlating, i.e., have regions of their phase diagram where constant-volume equilibrium fluctuations in the virial and potential energy are strongly correlated. A binary...... Buckingham liquid is cooled to a viscous phase and shown to have isomorphs, which are curves in the phase diagram along which structure and dynamics in appropriate units are invariant to a good approximation. To test this, the radial distribution function, and both the incoherent and coherent intermediate...

  11. Transmission-lattice based geometric phase analysis for evaluating the dynamic deformation of a liquid surface.

    Science.gov (United States)

    Shi, Wenxiong; Huang, Xianfu; Liu, Zhanwei

    2014-05-05

    Quantitatively measuring a dynamic liquid surface often presents a challenge due to high transparency, fluidity and specular reflection. Here, a novel Transmission-Lattice based Geometric Phase Analysis (TLGPA) method is introduced. In this method, a special lattice is placed underneath a liquid to be tested and, when viewed from above, the phase of the transmission-lattice image is modulated by the deformation of the liquid surface. Combining this with multi-directional Newton iteration algorithms, the dynamic deformation field of the liquid surface can be calculated from the phase variation of a series of transmission-lattice images captured at different moments. The developed method has the advantage of strong self-adaption ability to initial lattice rotational errors and this is discussed in detail. Dynamic 3D ripples formation and propagation was investigated and the results obtained demonstrated the feasibility of the method.

  12. Comparative study of nanocarbons synthesized between electrodes in liquid phase by solution plasma

    Science.gov (United States)

    Lee, Hoonseung; Wada, Yuta; Kaneko, Amane; Lun Li, Oi; Ishizaki, Takahiro

    2018-01-01

    For several decades, the development of synthesis processes and designs for carbon materials such as graphites, carbon nanotubes, and graphenes has been continuous because of their superior physicochemical properties. The liquid-phase electric discharge process, known as the solution plasma process (SPP), has emerged as a potential synthesis process for carbon materials; however, liquid discharge in organic solutions has not yet been thoroughly investigated. In this study, plasma discharges in benzene (C6H6) and pyridine (C5H5N) were conducted. During the discharge, two types of nanocarbons with different crystallinities were synthesized simultaneously in different reaction fields: between electrodes and in a liquid phase. The nanocarbons grown between electrodes were collected and then compared with the nanocarbons produced in the liquid phase after discharge. All carbon samples were measured using various techniques such as transmission electron microscopy (TEM), the nitrogen absorption–desorption method, X-ray diffraction (XRD), Raman spectroscopy, CHN elemental analysis, and X-ray photoelectron spectroscopy (XPS). Nanocarbons grown between electrodes in benzene or pyridine were found to be graphite structures, while the nanocarbons produced in the liquid phase were amorphous carbons. On the basis of the results obtained, the formation and growth of the two types of nanocarbon materials synthesized by SPP and their dependence on the position of the reaction field in plasma in the liquid phase are discussed.

  13. Stability and kinetic studies of supported ionic liquid phase catalysts for hydroformylation of propene

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco

    2005-01-01

    Supported ionic liquid phase (SILP) catalysts have been studied with regard to their long-term stability in the continuous gas-phase hydroformylation of propene. Kinetic data have been acquired by variation of temperature, pressure, syngas composition, substrate concentration, and residence time...

  14. Extraction and stability of selected proteins in ionic liquid based aqueous two phase systems

    NARCIS (Netherlands)

    Desai, R.K.; Streefland, M.; Wijffels, R.H.; Eppink, M.H.M.

    2014-01-01

    Ionic liquid-based aqueous two-phase extraction of a plant protein, Rubisco (Ribulose-1,5-biphosphate carboxylase oxygenase), using Iolilyte 221 PG and sodium potassium phosphate buffer, was investigated as a new alternative extraction method and compared with a conventional PEG-based two-phase

  15. Entrainment phenomenon in gas–liquid two-phase flow: A review

    Indian Academy of Sciences (India)

    The gas–liquid separation equipments are aimed to be designed for maximum efficiency of phase separation. In order to maximize their capacity the flow rates are required to be optimized for the capital cost of equipment. This leads to the situation where the gas phase leaves the separation interface with high velocities and ...

  16. Global phase diagram and quantum spin liquids in a spin-1/2 triangular antiferromagnet

    Science.gov (United States)

    Gong, Shou-Shu; Zhu, W.; Zhu, J.-X.; Sheng, D. N.; Yang, Kun

    2017-08-01

    We study the spin-1 /2 Heisenberg model on the triangular lattice with the nearest-neighbor J1>0 , the next-nearest-neighobr J2>0 Heisenberg interactions, and the additional scalar chiral interaction Jχ(S⃗i×S⃗j) .S⃗k for the three spins in all the triangles using large-scale density matrix renormalization group calculation on cylinder geometry. With increasing J2 (J2/J1≤0.3 ) and Jχ (Jχ/J1≤1.0 ) interactions, we establish a quantum phase diagram with the magnetically ordered 120∘, stripe, and noncoplanar tetrahedral phase. In between these magnetic order phases, we find a chiral spin liquid (CSL) phase, which is identified as a ν =1 /2 bosonic fractional quantum Hall state with possible spontaneous rotational symmetry breaking. By switching on the chiral interaction, we find that the previously identified spin liquid in the J1-J2 triangular model (0.08 ≲J2/J1≲0.15 ) shows a phase transition to the CSL phase at very small Jχ. We also compute the spin triplet gap in both spin liquid phases, and our finite-size results suggest a large gap in the odd topological sector but a small or vanishing gap in the even sector. We discuss the implications of our results on the nature of the spin liquid phases.

  17. Physico-Chemical Properties and Phase Behaviour of Pyrrolidinium-Based Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Urszula Domańska

    2010-04-01

    Full Text Available A review of the relevant literature on 1-alkyl-1-methylpyrrolidinium-based ionic liquids has been presented. The phase diagrams for the binary systems of {1-ethyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate [EMPYR][CF3SO3] + water, or + 1-butanol} and for the binary systems of {1-propyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate [PMPYR][CF3SO3] + water, or + an alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol} have been determined at atmospheric pressure using a dynamic method. The influence of alcohol chain length was discussed for the [PMPYR][CF3SO3]. A systematic decrease in the solubility was observed with an increase of the alkyl chain length of an alcohol. (Solid + liquid phase equilibria with complete miscibility in the liquid phase region were observed for the systems involving water and alcohols. The solubility of the ionic liquid increases as the alkyl chain length on the pyrrolidinium cation increases. The correlation of the experimental data has been carried out using the Wilson, UNIQUAC and the NRTL equations. The phase diagrams reported here have been compared to the systems published earlier with the 1-alkyl-1-methylpyrrolidinium-based ionic liquids. The influence of the cation and anion on the phase behaviour has been discussed. The basic thermal properties of pure ILs, i.e., melting temperature and the enthalpy of fusion, the solid-solid phase transition temperature and enthalpy have been measured using a differential scanning microcalorimetry technique.

  18. Ag-In transient liquid phase bonding for high temperature stainless steel micro actuators

    OpenAIRE

    Andersson, Martin

    2013-01-01

    A stainless steel, high temperature, phase change micro actuator has been demonstrated using the solid-liquid phase transition of mannitol at 168°C and In-Ag transient liquid phase diffusion bonding. Joints created with this bonding technique can sustain temperatures up to 695°C, while being bonded at only 180°C, and have thicknesses between 1.4 to 6.0 μm. Physical vapour deposition, inkjet printing and electroplating have been evaluated as deposition methods for bond layers. For actuation, c...

  19. Liquid-phase combinatorial library synthesis: recent advances and future perspectives.

    Science.gov (United States)

    Barot, Kuldipsinh P; Nikolova, Stoyanka; Ivanov, Illiyan; Ghate, Manjunath D

    2014-01-01

    Liquid-phase combinatorial library synthesis is commonly developed into the viable alternatives or adjunct across the broad spectrum of polymer-supported organic chemistry. It includes the use of soluble polymer supports in the combinatorial synthesis of peptides and small-molecular library compounds which act as catalyst and reagent supports. It also includes high throughput biological screening with generation and evaluation of chemical leads for drug discovery development. In this review, liquid-phase combinatorial library synthesis is shown as the most efficient method of choice for the synthesis of most of the combinatorial library compounds with specific approaches from different groups that state potentials of solution-phase combinatorial synthesis.

  20. Determination of household and industrial chemicals, personal care products and hormones in leafy and root vegetables by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Aparicio, Irene; Martín, Julia; Abril, Concepción; Santos, Juan Luis; Alonso, Esteban

    2018-01-19

    A multiresidue method has been developed for the determination of emerging pollutants in leafy and root vegetables. Selected compounds were 6 perfluoroalkyl compounds (5 perfluorocarboxylic acids and perfluorooctanesulfonic acid), 3 non-ionic surfactants (nonylphenol and nonylphenolethoxylates), 8 anionic surfactants (4 alkylsulfates and 4 linear alkylbenzene sulfonates), 4 preservatives (parabens), 2 biocides (triclosan and triclocarban), 2 plasticizers (bisphenol A and di-(2-ethylhexyl)phthalate), 6 UV-filters (benzophenones) and 4 hormones. The method is based on ultrasound-assisted extraction, clean-up by dispersive solid-phase extraction (d-SPE) and liquid chromatography-tandem mass spectrometry analysis. Due to the diversity of the physico-chemical properties of the target compounds, and to better evaluate the influence of sample treatment variables in extraction efficiencies, Box-Behnken design was applied to optimize extraction solvent volume, number of extraction cycles and d-SPE sorbent amount. Linearity (R 2 ) higher than 0.992, accuracy (expressed as relative recoveries) in the range from 81 to 126%, precision (expressed as relative standard deviation) lower than 19% and limits of detection between 0.025 and 12.5ngg -1 dry weight were achieved. The method was applied to leafy vegetables (lettuce, spinach and chard) and root vegetables (carrot, turnip and potato) from a local market. The highest concentrations corresponded to the surfactants reaching levels up to 114ngg -1 (dry weight), in one of the lettuce samples analyzed. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Migration of liquid phase from the primary/peritectic interface in a temperature gradient

    Science.gov (United States)

    Peng, Peng; Li, XinZhong; Su, YanQing; Guo, JingJie

    2016-07-01

    The migration of the liquid droplets from the primary α/peritectic β interface at the peritectic temperature TP has been observed and analyzed in a Sn-Ni peritectic alloy. During the isothermal annealing stage of the interrupted directional solidification, a concentration gradient is established across the liquid droplets along the direction of the temperature gradient due to the temperature gradient zone melting. Simultaneous remelting/resolidification at the top/bottom of the liquid droplets by this concentration gradient have been confirmed to lead to migration of these droplets towards higher temperatures. The dependence of the migration distance of the liquid droplets on isothermal annealing time has been well predicted. Furthermore, since the lengths of the liquid droplet are not uniform along the direction of the temperature gradient, the remelting/resolidification rates which are dependent on the local morphology of liquid droplet are different at different local positions of the liquid droplets. It has been demonstrated that the morphology of the liquid droplet was also influenced by the morphologies of the liquid phase themselves. Therefore, the morphology of the liquid droplet itself changes from spherical to some kinds of irregular shapes during its migration.

  2. Simulation of non-ideal gases and liquid-gas phase transitions by lattice Boltzmann equation

    CERN Document Server

    Shan, X; Xiaowen Shan; Hudong Chen

    1994-01-01

    We describe in detail a recently proposed lattice-Boltzmann model for simulating flows with multiple phases and components. In particular, the focus is on the modeling of one-component fluid systems which obey non-ideal gas equations of state and can undergo a liquid-gas type phase transition. The model is shown to be momentum-conserving. From the microscopic mechanical stability condition, the densities in bulk liquid and gas phases are obtained as functions of a temperature-like parameter. Comparisons with the thermodynamic theory of phase transition show that the LBE model can be made to correspond exactly to an isothermal process. The density profile in the liquid-gas interface is also obtained as function of the temperature-like parameter and is shown to be isotropic. The surface tension, which can be changed independently, is calculated. The analytical conclusions are verified by numerical simulations. (To appear in Phys. Rev. E)

  3. A numerical study of aerosol influence on mixed-phase stratiform clouds through modulation of the liquid phase

    Directory of Open Access Journals (Sweden)

    G. de Boer

    2013-02-01

    Full Text Available Numerical simulations were carried out in a high-resolution two-dimensional framework to increase our understanding of aerosol indirect effects in mixed-phase stratiform clouds. Aerosol characteristics explored include insoluble particle type, soluble mass fraction, influence of aerosol-induced freezing point depression and influence of aerosol number concentration. Simulations were analyzed with a focus on the processes related to liquid phase microphysics, and ice formation was limited to droplet freezing. Of the aerosol properties investigated, aerosol insoluble mass type and its associated freezing efficiency was found to be most relevant to cloud lifetime. Secondary effects from aerosol soluble mass fraction and number concentration also alter cloud characteristics and lifetime. These alterations occur via various mechanisms, including changes to the amount of nucleated ice, influence on liquid phase precipitation and ice riming rates, and changes to liquid droplet nucleation and growth rates. Alteration of the aerosol properties in simulations with identical initial and boundary conditions results in large variability in simulated cloud thickness and lifetime, ranging from rapid and complete glaciation of liquid to the production of long-lived, thick stratiform mixed-phase cloud.

  4. Liquid-based stationary phase for deterministic lateral displacement separation in microfluidics.

    Science.gov (United States)

    Du, Siqi; Shojaei-Zadeh, Shahab; Drazer, German

    2017-10-25

    Deterministic lateral displacement (DLD) is a promising separation scheme in microfluidic systems. In traditional DLD, a periodic array of solid posts induces the separative migration of suspended particles moving through the system. Here, we present a radical departure from traditional DLD systems and use an array of anchored liquid-bridges as the stationary phase in the DLD device. The liquid-bridges are created between two parallel plates and anchored to the bottom one by cylindrical wells. We show that the non-linear particle dynamics observed in traditional DLD systems is also present in the anchored-liquid case, enabling analogous size-based separation of suspended particles. The use of liquid-bridges as the stationary phase presents additional possibilities in separation technologies, potentially eliminating or significantly reducing clogging, enabling renewable and/or reconfigurable systems, allowing a different set of fabrication methods and providing alternative ways to separate particles based on their interaction with liquid-liquid interfaces. Some of these advantages could also extend to filtration methods based on similar liquid-based stationary phases.

  5. Liquid Crystals of Dendron-Like Pt Complexes Processable Into Nanofilms Dendrimers. Phase 2. Cholesteric Liquid Crystal Glass Platinum Acetylides

    Science.gov (United States)

    2014-08-01

    Std. Z39.18 Final Report Liquid Crystals of Dendron-Like Pt Complexes Processable Into Nanofilms. Dendrimers Eduardo Arias...to pack and also the presence of a polar group. Figure 4. Summary of phase behavior. DENDRIMERS New Denrimers. The synthesis...purification and some spectral characteristics of the new dendrimers shown in Fig 5 were reported in AFOSR FA9550-11-1-0169, May, 2013. Further

  6. Liquid-Phase Deposition of CIS Thin Layers: Final Report, February 2003--July 2005

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, F.; Pirouz, P.

    2006-02-01

    The goal of this project was to fabricate single-phase CIS (a-Cu-In-Se, stoichiometric composition: CuInSe2) thin films for photovoltaic applications from a liquid phase - a Cu-In-Se melt of appropriate composition. This approach of liquid-phase deposition (LPD) is based on the new phase diagram we have established for Cu-In-Se, the first complete equilibrium phase diagram of this system. The liquidus projection exhibits four composition fields in which the primary solid phase, i.e., the first solid material that forms on cooling down from an entirely liquid state, is a-CuInSe2. Remarkably, none of the four composition fields is anywhere near the stoichiometric composition (CuInSe2) of a-CuInSe2. The results demonstrate that the proposed technique is indeed capable of producing films with a particularly large grain size and a correspondingly low density of grain boundaries. To obtain films sufficiently thin for solar cell applications and with a sufficiently smooth surface, it is advantageous to employ a sliding boat mechanism. Future work on liquid-phase deposition of CIS should focus on the interaction between the melt and the substrate surface, the resulting CIS interfaces, the surface morphology of the LPD-grown films, and, of course, the electronic properties of the material.

  7. Phase separation in polymer solutions. I. Liquid-liquid phase separation of PPO poly (2, 6-dimethyl 1, 4-phenylene oxide) in binary mixtures with toluene and ternary mixtures with toluene and ethyl alcohol

    NARCIS (Netherlands)

    van Emmerik, P.T.; Smolders, C.A.

    1972-01-01

    In the system poly(2, 6-dimethy1-1, 4-phenylene oxide) (PPO)-toluene three phase separation lines can be detected: the melting point curve, the cloud point curve, and the spinodial. Because crystallization of PPO occurs very slowly, a phase transition will always be initiated by liquid-liquid phase

  8. Ecotoxicology of heavy metals: Liquid-phase extraction by nanosorbents

    Science.gov (United States)

    Burakov, A.; Romantsova, I.; Babkin, A.; Neskoromnaya, E.; Kucherova, A.; Kashevich, Z.

    2015-11-01

    The paper considers the problem of extreme toxicity heavy metal compounds dissolved in wastewater and liquid emissions of industrial enterprises to living organisms and environment as a whole. The possibility of increasing extraction efficiency of heavy metal ions by sorption materials was demonstrated. The porous space of the latter was modified by carbon nanotubes (CNTs) during process of the chemical vapour deposition (CVD) of carbon on metal oxide catalysts. The increasing of the sorption capacity (10-30%) and the sorption rate of nanomodified activated carbons in comparison with standard materials in the example of absorption of Co2+ and Ni2+ ions from aqueous solutions was proven.

  9. Visualization and research of gas-liquid two phase flow structures in cylindrical channel

    Directory of Open Access Journals (Sweden)

    Stefański Sebastian

    2017-01-01

    Full Text Available Two-phase flows are commonly found in many industries, especially in systems, where efficient and correct functioning depend on specific values of flow parameters. In thermal engineering and chemical technology the most popular types of two-phase mixture are gas-liquid or liquid-vapour mixtures. Bubbles can create in flow different structures and determine diverse properties of flow (velocity of phase, void fraction, fluctuations of pressure, pipe vibrations, etc.. That type of flow is difficult to observe, especially in liquid-vapour mixture, where vapour is being made by heating the medium. Production of vapour and nucleation process are very complicated issues, which are important part of two-phase flow phenomenon. Gas-liquid flow structures were observed and described with figures, but type of structure depends on many parameters. Authors of this paper made an attempt to simulate gas-liquid flow with air and water. In the paper there was presented specific test stand built to observe two-phase flow structures, methodology of experiment and conditions which were maintained during observation. The paper presents also the structures which were observed and the analysis of results with reference to theoretical models and diagrams available in literature.

  10. Pressureless Reaction Sintering of AlON using Aluminum Orthophosphate as a Transient Liquid Phase

    Energy Technology Data Exchange (ETDEWEB)

    Michael Bakas; Henry Chu

    2009-01-01

    Use of aluminum oxynitride (AlON) in transparent armor systems has been difficult due to the expense and limitations of the processing methods currently necessary to achieve transparency. Development of a pressureless processing method based on direct reaction sintering of alumina and aluminum nitride powders would reduce costs and provide a more flexible and practical manufacturing method. It may be possible to develop such a processing method using liquid phase sintering; as long as the liquid phase does not remain in the final sample. AlPO4 forms a liquid phase with Al2O3 and AlN at the temperatures required to sinter AlON, and slowly decomposes into P2O5 and alumina. Therefore, it was investigated as a possible transient liquid phase for reaction-sintered AlON. Small compacts of alumina and aluminum nitride with up to of 15wt% AlPO4 additive were pressed and sintered. It was found that AlPO4 formed the requisite transient liquid phase, and it was possible to adjust the process to produce AlON samples with good transmission and densities of 3.66-3.67 g/cc. XRD confirmed the samples formed were AlON, with no trace of any remaining phosphate phases or excess alumina or aluminum nitride. Based on the results, it was concluded that AlPO4 could be utilized as a transient liquid phase to improve the density and transmission of AlON produced by pressureless reaction sintering.

  11. Thermodynamic modeling of liquid–liquid phase change solvents for CO2 capture

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; von Solms, Nicolas; Thomsen, Kaj

    2016-01-01

    A thermodynamic model based on Extended UNIQUAC framework has been developed in this work for the de-mixing liquid–liquid phase change solvents, DEEA (2-(diethylamino)ethanol) and MAPA (3-(methylamino)propylamine). Parameter estimation was performed for two ternary systems, H2O-DEEA-CO2 and H2O......-MAPA-CO2, and a quaternary system, H2O-DEEA-MAPA-CO2 (phase change system), by using different types of experimental data (equilibrium and thermal) consisting of pure amine vapor pressure, vapor-liquid equilibrium, solid-liquid equilibrium, liquid–liquid equilibrium, excess enthalpy, and heat of absorption...... of CO2 in aqueous amine solutions. 94 model parameters and 6 thermodynamic properties were fitted to approximately 1500 experimental data. The developed model accurately represents the equilibrium and thermal data for the studied systems with a single unique set of parameters. The model parameters...

  12. Direct measurement of the propagation of the phase-transition region of liquid crystals

    Science.gov (United States)

    Sato, Takahiro; Katayama, Kenji

    2017-03-01

    Many types of active matter, such as biological cells, have liquid-crystalline membranes, which are soft and flexible in their interactions with their surroundings and sometimes allow molecular-structural or -orientational changes to extend for long distances, owing to long-range molecular interactions. Despite the technological and fundamental importance of these long-range changes, there is no good physical property with which to express them for the liquid crystal. Here, we show direct measurements of the propagation of structural or orientational changes due to long-range molecular interactions in liquid crystals. We induced a patterned phase transition in a liquid crystal via illumination with a fringe pattern and observed the propagation of the phase-transition region. We determined that the propagation occurred in a ballistic manner with a velocity of 80-110 m/s and that two types of propagation—side-by-side and head-to-tail molecular interactions—were found.

  13. Reversed-phase liquid chromatography of radiolabeled peptides using a C18 guard-PAK precolumn system

    Energy Technology Data Exchange (ETDEWEB)

    Carriere, P.D.; Bennett, H.P. (McGill Univ., Montreal, Quebec (Canada))

    1989-03-01

    In order to avoid radioactive contamination of high-performance liquid chromatography columns and injectors, we have investigated the use of a Guard-PAK precolumn system for the chromatography of ({sup 125}I) labeled peptides. Two gonadotropin-releasing hormone analogs: (1) (D-Ala6-des-Gly10)-GnRH (GnRH-(Ala6)) and (2) (D-Ser(TBu)6-des-Gly10)-GnRH (GnRH-(Ser6)) and rat prolactin (r-PRL) were radiolabeled with {sup 125}I and subjected to reversed-phase liquid chromatography using a C18 Guard-PAK precolumn system. Major peak fractions of purified ({sup 125}I)GnRH-(Ala6), ({sup 125}I)GnRH-(Ser6), and ({sup 125}I)r-PRL eluted at 24%, 28%, and 55% acetonitrile, respectively. Purified ({sup 125}I)GnRH analogs showed specific high affinity binding to rat anterior pituitary gland membranes (specific activity: 1500-1700 Ci/mmol). Purified ({sup 125}I)r-PRL showed high affinity binding to r-PRL antibody by RIA (specific activity: 70-75 microCi/micrograms). This rapid and efficient chromatographic method should be useful in the separation of a wide range of radiolabeled protein and peptide molecules.

  14. Solid-Phase Extraction Combined with High Performance Liquid ...

    African Journals Online (AJOL)

    Satisfactory precision was obtained both for intra-assay (RSD, 1.8 to 4.4 %) and inter-assay (RSD, 2.0 to 4.7 %). Conclusion: The proposed method is environmentally friendly, inexpensive and convenient, and should be helpful in analyzing estrogens in biological, environmental and food samples. Keywords: Solid-phase ...

  15. The boundary curve of thermodynamic stability of the liquid phase ...

    African Journals Online (AJOL)

    It was established that, in the region of positive pressures, the generalised Berthelot's equation describes the position of the spinodal on the phase diagram better than the generalised van der Waals equation, while preference is given to the generalised van der Waals equation in the region of negative pressures at low ...

  16. Solid-Phase Extraction Combined with High Performance Liquid ...

    African Journals Online (AJOL)

    be helpful in analyzing estrogens in biological, environmental and food samples. Keywords: Solid-phase extraction, Milk, Estrogens, High ... systems are completely different from the traditional ones. Duo to the result of modern ... Therefore, to ensure the food safety and human health, it is essential to develop rapid, simple,.

  17. Poincaré-sphere representation of phase-mostly twisted nematic liquid crystal spatial light modulators

    OpenAIRE

    Durán Bosch, Vicente Andrés; Clemente Pesudo, Pedro Javier; Martínez León, Lluís; Climent Jordà, Vicent; Lancis Sáez, Jesús

    2009-01-01

    We establish necessary conditions in order to design a phase-only wave front modulation system from a liquid crystal display. These conditions determine the dependence of the polarization state of the light emerging from the display on the addressing gray level. The analysis, which is carried out by means of the coherence-matrix formalism, includes the depolarization properties of the device. Two different types of polarization distributions at the output of the liquid crystal cel...

  18. Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

    Science.gov (United States)

    Xu, Xinhua; Wang, Xiaogang; Wu, Meifen

    2014-01-01

    The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

  19. Liquid-liquid phase-separation in polydisperse polymer-solutions : The Distribution Coefficient

    NARCIS (Netherlands)

    ten Brinke, G.; Szleifer, I.

    1995-01-01

    Phase separation in polymer solutions is highly asymmetric: an inhomogeneous dilute phase of isolated coils is in equilibrium with a homogeneous concentrated solution. Many deviations from the simple Flory-Huggins predictions, found experimentally, can be traced back to this fact. Here, a previously

  20. Multiple Reaction Monitoring Mode Based Liquid Chromatography-Mass Spectrometry Method for Simultaneous Quantification of Brassinolide and Other Plant Hormones Involved in Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Deepak M. Kasote

    2016-01-01

    Full Text Available Plant hormones are the key regulators of adaptive stress response. Abiotic stresses such as drought and salt are known to affect the growth and productivity of plants. It is well known that the levels of plant hormones such as zeatin (ZA, abscisic acid (ABA, salicylic acid (SA, jasmonic acid (JA, and brassinolide (BR fluctuate upon abiotic stress exposure. At present, there is not any single suitable liquid chromatography-mass spectrometry (LC-MS method for simultaneous analysis of BR and other plant hormones involved in abiotic stresses. In the present study, we developed a simple, sensitive, and rapid method for simultaneous analysis of five major plant hormones, ZA, ABA, JA, SA, and BR, which are directly or indirectly involved in drought and salt stresses. The optimized extraction procedure was simple and easy to use for simultaneous measurement of these plant hormones in Arabidopsis thaliana. The developed method is highly reproducible and can be adapted for simultaneous measurement of changes in plant hormones (ZA, ABA, JA, SA, and BR in response to abiotic stresses in plants like A. thaliana and tomato.

  1. Multiple Reaction Monitoring Mode Based Liquid Chromatography-Mass Spectrometry Method for Simultaneous Quantification of Brassinolide and Other Plant Hormones Involved in Abiotic Stresses.

    Science.gov (United States)

    Kasote, Deepak M; Ghosh, Ritesh; Chung, Jun Young; Kim, Jonggeun; Bae, Inhwan; Bae, Hanhong

    2016-01-01

    Plant hormones are the key regulators of adaptive stress response. Abiotic stresses such as drought and salt are known to affect the growth and productivity of plants. It is well known that the levels of plant hormones such as zeatin (ZA), abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), and brassinolide (BR) fluctuate upon abiotic stress exposure. At present, there is not any single suitable liquid chromatography-mass spectrometry (LC-MS) method for simultaneous analysis of BR and other plant hormones involved in abiotic stresses. In the present study, we developed a simple, sensitive, and rapid method for simultaneous analysis of five major plant hormones, ZA, ABA, JA, SA, and BR, which are directly or indirectly involved in drought and salt stresses. The optimized extraction procedure was simple and easy to use for simultaneous measurement of these plant hormones in Arabidopsis thaliana. The developed method is highly reproducible and can be adapted for simultaneous measurement of changes in plant hormones (ZA, ABA, JA, SA, and BR) in response to abiotic stresses in plants like A. thaliana and tomato.

  2. Stability analysis of whirling composite shells partially filled with two liquid phases

    Energy Technology Data Exchange (ETDEWEB)

    Sahebnasagh, Mohammad [Department of Mechanical Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Nikkhah-Bahrami, Mansour; Firouz-Abadi, Roohollah [Department of Aerospace Engineering, Sharif University, Tehran (Iran, Islamic Republic of)

    2017-05-15

    In this paper, the stability of whirling composite cylindrical shells partially filled with two liquid phases is studied. Using the first-order shear shell theory, the structural dynamics of the shell is modeled and based on the Navier-Stokes equations for ideal liquid, a 2D model is developed for liquid motion at each section of the cylinder. In steady state condition, liquids are supposed to locate according to mass density. In this study, the thick shells are investigated. Using boundary conditions between liquids, the model of coupled fluid-structure system is obtained. This coupled fluid-structure model is employed to determine the critical speed of the system. The effects of the main variables on the stability of the shell are studied and the results are investigated.

  3. Novel materials and methods for solid-phase extraction and liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, Diana [Iowa State Univ., Ames, IA (United States)

    1997-06-24

    This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

  4. Migration of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling

    Directory of Open Access Journals (Sweden)

    Peng Hao

    2011-01-01

    Full Text Available Abstract The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt.%, the heat flux is from 10 to 100 kW·m-2, and the initial liquid-level height is from 1.3 to 3.4 cm. The experimental results indicate that the migration ratio of carbon nanotube increases with the increase of the outside diameter or the length of carbon nanotube. For the fixed type of carbon nanotube, the migration ratio decreases with the increase of the oil concentration or the heat flux, and increases with the increase of the initial liquid-level height. The migration ratio of carbon nanotube increases with the decrease of dynamic viscosity of refrigerant or the increase of liquid phase density of refrigerant. A model for predicting the migration ratio of carbon nanotubes in the refrigerant-based nanofluid pool boiling is proposed, and the predictions agree with 92% of the experimental data within a deviation of ±20%.

  5. Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Shiina Tatsuo

    2016-01-01

    Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

  6. The method to calculate concentration of CO2 and H2S in the liquid phase.

    Directory of Open Access Journals (Sweden)

    YUDIN Pavel Evgenievich

    2017-08-01

    Full Text Available The article proposes the method to calculate the necessary concentration of dissolved gases in the liquid phase. It also deals with development of the computer program that could consider all the main parameters of the tests. The numerous mathematical calculations resulted in formulation of the method to calculate concentration of dissolved gases in the liquid phase. The implementation of the developed model in the form of the software product «Autoclave 2.1» is presented. The developed methodology for calculating the concentration of dissolved gases in the liquid phase is designed to perform accelerated tests that concern resistance of internal anticorrosive coatings of pipelines to aggressive media and explosive decompression, to intensify corrosion processes and to identify the main mechanisms and patterns of changes in the physical, mechanical and operational properties of coatings from hydrothermal influences of fishing environments.

  7. Phase Change Predictions for Liquid Fuel in Contact with Steel Structure using the Heat Conduction Equation

    OpenAIRE

    Brear, D. J.

    1998-01-01

    When liquid fuel makes contact with steel structure the liquid can freeze as a crust and the structure can melt at the surface. The melting and freezing processes that occur can influence the mode of fuel freezing and hence fuel relocation. Furthermore the temperature gradients established in the fuel and steel phases determine the rate at which heat is transferred from fuel to steel. In this memo the 1-D transient heat conduction equations are applied to the case of initially liquid UO2 brou...

  8. Magnetic Hamiltonian and phase diagram of the quantum spin liquid Ca10Cr7O28

    Science.gov (United States)

    Balz, Christian; Lake, Bella; Nazmul Islam, A. T. M.; Singh, Yogesh; Rodriguez-Rivera, Jose A.; Guidi, Tatiana; Wheeler, Elisa M.; Simeoni, Giovanna G.; Ryll, Hanjo

    2017-05-01

    A spin liquid is a new state of matter with topological order where the spin moments continue to fluctuate coherently down to the lowest temperatures rather than develop static long-range magnetic order as found in conventional magnets. For spin liquid behavior to arise in a material the magnetic Hamiltonian must be "frustrated", where the combination of lattice geometry, interactions, and anisotropies gives rise to competing spin arrangements in the ground state. Theoretical Hamiltonians which produce spin liquids are spin ice, the Kitaev honeycomb model, and the kagome antiferromagnet. Spin liquid behavior, however, in real materials is rare because they can only approximate these Hamiltonians and often have weak higher-order terms that destroy the spin liquid state. Ca10Cr7O28 is a new quantum spin liquid candidate with magnetic Cr5 + ions that possess quantum spin number S =½ . The spins are entirely dynamic in the ground state and the excitation spectrum is broad and diffuse, as is typical of spinons which are the excitations of a spin liquid. In this paper we determine the Hamiltonian of Ca10Cr7O28 using inelastic neutron scattering under high magnetic field to induce a field-polarized paramagnetic ground state and spin-wave excitations that can be fitted to extract the interactions. We further explore the phase diagram by using inelastic neutron scattering and heat capacity measurements and establish the boundaries of the spin liquid phase as a function of magnetic field and temperature. Our results show that Ca10Cr7O28 consists of distorted kagome bilayers with several isotropic ferromagnetic and antiferromagnetic interactions where, unexpectedly, the ferromagnetic interactions are stronger than the antiferromagnetic ones. This complex Hamiltonian does not correspond to any known spin liquid model and points to new directions in the search for quantum spin liquid behavior.

  9. Analysis of thyroid hormones in biological samples using stable isotope dilution liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    This poster presentation will describe analytical chemistry methods for measuring thyroid hormones and related precursors and metabolites in very small tissue or plasma samples. These methods are amenable to measure thyroid hormones in amphibian tadpoles or small mammals used as ...

  10. Cold flame on Biofilm - Transport of Plasma Chemistry from Gas to Liquid Phase

    Science.gov (United States)

    Kong, Michael

    2014-10-01

    One of the most active and fastest growing fields in low-temperature plasma science today is biological effects of gas plasmas and their translation in many challenges of societal importance such as healthcare, environment, agriculture, and nanoscale fabrication and synthesis. Using medicine as an example, there are already three FDA-approved plasma-based surgical procedures for tissue ablation and blood coagulation and at least five phase-II clinical trials on plasma-assisted wound healing therapies. A key driver for realizing the immense application potential of near room-temperature ambient pressure gas plasmas, commonly known as cold atmospheric plasmas or CAP, is to build a sizeable interdisciplinary knowledge base with which to unravel, optimize, and indeed design how reactive plasma species interact with cells and their key components such as protein and DNA. Whilst a logical objective, it is a formidable challenge not least since existing knowledge of gas discharges is largely in the gas-phase and therefore not directly applicable to cell-containing matters that are covered by or embedded in liquid (e.g. biofluid). Here, we study plasma inactivation of biofilms, a jelly-like structure that bacteria use to protect themselves and a major source of antimicrobial resistance. As 60--90% of biofilm is made of water, we develop a holistic model incorporating physics and chemistry in the upstream CAP-generating region, a plasma-exit region as a buffer for as-phase transport, and a downstream liquid region bordering the gas buffer region. A special model is developed to account for rapid chemical reactions accompanied the transport of gas-phase plasma species through the gas-liquid interface and for liquid-phase chemical reactions. Numerical simulation is used to illustrate how key reactive oxygen species (ROS) are transported into the liquid, and this is supported with experimental data of both biofilm inactivation using plasmas and electron spin spectroscopy (ESR

  11. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    Directory of Open Access Journals (Sweden)

    Jin J.H.

    2013-05-01

    Full Text Available A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe∼102 which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  12. Computerized Liquid Crystal Phase Identification by Neural Networks Analysis of Polarizing Microscopy Textures

    Science.gov (United States)

    Karaszi, Zoltan; Konya, Andrew; Dragan, Feodor; Jakli, Antal; CPIP/LCI; CS Dept. of Kent State University Collaboration

    Polarizing optical microscopy (POM) is traditionally the best-established method of studying liquid crystals, and using POM started already with Otto Lehman in 1890. An expert, who is familiar with the science of optics of anisotropic materials and typical textures of liquid crystals, can identify phases with relatively large confidence. However, for unambiguous identification usually other expensive and time-consuming experiments are needed. Replacement of the subjective and qualitative human eye-based liquid crystal texture analysis with quantitative computerized image analysis technique started only recently and were used to enhance the detection of smooth phase transitions, determine order parameter and birefringence of specific liquid crystal phases. We investigate if the computer can recognize and name the phase where the texture was taken. To judge the potential of reliable image recognition based on this procedure, we used 871 images of liquid crystal textures belonging to five main categories: Nematic, Smectic A, Smectic C, Cholesteric and Crystal, and used a Neural Network Clustering Technique included in the data mining software package in Java ``WEKA''. A neural network trained on a set of 827 LC textures classified the remaining 44 textures with 80% accuracy.

  13. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    Science.gov (United States)

    Chughtai, I. R.; Iqbal, W.; Din, G. U.; Mehdi, S.; Khan, I. H.; Inayat, M. H.; Jin, J. H.

    2013-05-01

    A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD) analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl) scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM) was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe˜102) which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  14. An electro-optic experimental study of an unusual liquid crystal phase transition

    Science.gov (United States)

    Staines, Daniel; Wicks, Derek; Havens, Austin; Fernsler, Jonathan

    2009-11-01

    Liquid crystal phases are highly sensitive to their surroundings and they interact with light in unusual ways: the index of refraction is different depending on the polarization of the incident light. This combination of properties makes them ideal for low-power liquid crystal displays (LCD's), ubiquitous in today's portable electronic devices. They are also beautiful: optical textures of liquid crystals show bright colors, with the color corresponding to the amount of retardation in the light polarized along different axes. These phases are fluid, but can nevertheless be highly ordered. We have developed a novel experimental analysis using a photometric calculation of microscopy images to perform a series of experiments on several liquid crystal materials, called ``de Vries'' smectics. Using this system, we examined how the structure of these phases changed under the influence of different boundary conditions, temperature, and applied electric fields. These unusual materials show the bizarre behavior of appearing to become less ordered with decreasing temperature. This phase, which is not fully understood, has advantageous optical properties that could lead to the next generation of liquid crystal displays.

  15. The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation of Ordered Phases

    Science.gov (United States)

    Curreri, Peter A. (Technical Monitor); Kelton, K. F.; Gangopadhyay, A.; Lee, G. W.; Hyers, R. W.; Rathz, R. J.; Rogers, J.; Schenk, T.; Simonet, V.; Holland-Moritz, D.

    2003-01-01

    Over fifty years ago, David Turnbull showed that the temperature of many metallic liquids could be decreased far below their equilibrium melting temperature before crystallization occurred. To explain those surprising results, Charles Frank hypothesized that the local structures of undercooled metallic liquids are different from those of crystal phases, containing a significant degree of icosahedral order that is incompatible with extended periodicity. Such structural differences must create a barrier to the formation crystal phases, explaining the observed undercooling behavior. If true, the nucleation from the liquid of phases with extended icosahedral order should be easier. Icosahedral order is often favored in small clusters, as observed recently in liquid-like clusters of pure Pb on the (111) surface of Si, for example. However, it has never been shown that an increasing preference for icosahedral phase formation can be directly linked with the development of icosahedral order in the undercooled liquid. Owing to the combination of very recent advances in levitation techniques and the availability of synchrotron x-ray and high flux neutron facilities, this is shown here.

  16. The Connection Between Local Icosahedral Order in Metallic Liquids and the Nucleation Behavior of Ordered Phases

    Science.gov (United States)

    Kelton, K. F.; Gangopadhyay, A. K.; Lee, G. W.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, M. B.; Schenk, T.; Simonet, V.

    2003-01-01

    Over fifty years ago, David Turnbull showed that the temperature of many metallic liquids could be decreased far below their equilibrium melting temperature before crystallization occurred. To explain those surprising results, Charles Frank hypothesized that the local structures of undercooled metallic liquids are different from those of crystal phases, containing a significant degree of icosahedral order that is incompatible with extended periodicity. Such structural differences must create a barrier to the formation crystal phases, explaining the observed undercooling behavior. If true, the nucleation from the liquid of phases with extended icosahedral order should be easier. Icosahedral order is often favored in small clusters, as observed recently in liquid-like clusters of pure Pb on the (111) surface of Si[3], for example. However, it has never been shown that an increasing preference for icosahedral phase formation can be directly linked with the development of icosahedral order in the undercooled liquid. Owing to the combination of very recent advances in levitation techniques and the availability of synchrotron x-ray and high flux neutron facilities, this is shown here.

  17. Controllable Liquid Artificial Dielectric S-Band Phase Shifters

    Science.gov (United States)

    1975-02-01

    tiructing suslyinsion dielectrics with desl •ped partlele dilstribt1ons to achievc fast res~prma tinx, a.nd largo stable phase shift. 2.4. L 3 TEIMIILMATrIu...T it * -i 3.-’, For;a rectangular waveiguide operatlin in the TEIo mode the maxim •ma power handling capability can be expressed by: P = 6.3x 10-4 ab

  18. Development of a method for comprehensive and quantitative analysis of plant hormones by highly sensitive nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Yoshihiro; Okazawa, Atsushi; Bamba, Takeshi; Kobayashi, Akio [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukusaki, Eiichiro, E-mail: fukusaki@bio.eng.osaka-u.ac.jp [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2009-08-26

    In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC-ESI-IT-MS/MS method showed ca. 5-10-fold greater sensitivity than capillary-LC-ESI-IT-MS/MS, and the detection limits (S/N = 3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (R{sup 2} values of 0.9937-1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC-ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1 mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.

  19. Revisiting dynamics near a liquid-liquid phase transition in Si and Ga: The fragile-to-strong transition

    Energy Technology Data Exchange (ETDEWEB)

    Cajahuaringa, Samuel; Koning, Maurice de, E-mail: dekoning@ifi.unicamp.br; Antonelli, Alex, E-mail: aantone@ifi.unicamp.br [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, São Paulo (Brazil)

    2013-12-14

    Using molecular dynamics simulations we analyze the dynamics of two atomic liquids that display a liquid-liquid phase transition (LLPT): Si described by the Stillinger-Weber potential and Ga as modeled by the modified embedded-atom model. In particular, our objective is to investigate the extent to which the presence of a dip in the self-intermediate scattering function is a manifestation of an excess of vibrational states at low frequencies and may be associated with a fragile-to-strong transition (FTST) across the LLPT, as suggested recently. Our results suggest a somewhat different picture. First, in the case of Ga we observe the appearance of an excess of vibrational states at low frequencies, even in the absence of the appearance of a dip in the self-intermediate scattering function across the LLPT. Second, studying the behavior of the shear viscosities traversing the LLPTs we find that both substances are fragile in character above and below their respective LLPT temperatures. Instead of a FTST in an absolute sense these findings are more in line with a view in which the LLPTs are accompanied by a transition from a more fragile to a less fragile liquid. Furthermore, we do not find this transition to correlate with the presence of a dip in the intermediate scattering function.

  20. High flux diode packaging using passive microscale liquid-vapor phase change

    Science.gov (United States)

    Bandhauer, Todd; Deri, Robert J.; Elmer, John W.; Kotovsky, Jack; Patra, Susant

    2017-09-19

    A laser diode package includes a heat pipe having a fluid chamber enclosed in part by a heat exchange wall for containing a fluid. Wicking channels in the fluid chamber is adapted to wick a liquid phase of the fluid from a condensing section of the heat pipe to an evaporating section of the heat exchanger, and a laser diode is connected to the heat exchange wall at the evaporating section of the heat exchanger so that heat produced by the laser diode is removed isothermally from the evaporating section to the condensing section by a liquid-to-vapor phase change of the fluid.

  1. Case-based reasoning approach for monitoring multi-phase liquid in pipeline

    Science.gov (United States)

    Kuzyakov, O. N.; Glukhikh, I. N.; Sidorova, A. E.; Andreeva, M. A.

    2017-10-01

    A method based on collecting, integrating and subsequence analyzing data on multi-phase liquid flow condition in pipeline is suggested in the paper. The principles of constructing multi-component liquid control system with the use of ultrasonic signal as a sensing one and initial execution algorithm of ultrasonic emitters-receivers with subsequent change of roles are presented as well. CBR method used while identifying multi-phase condition is an element of processing part of the system – intellectual decision-support system.

  2. Copyrolysis of wood biomass and synthetic polymers mixtures. Part 2. Characterisation of the liquid phases

    Energy Technology Data Exchange (ETDEWEB)

    Marin, N.; Collura, S.; Weber, J.V. [Laboratoire de Chimie et Applications, Universite de Metz, IUT, rue Victor Demange, 57500 Saint Avold (France); Sharypov, V.I.; Beregovtsova, N.G.; Baryshnikov, S.V.; Kutnetzov, B.N. [Institute of Chemistry and Chemical Technology SB RAS, Academgorodok, 660049 Krasnoyarsk (Russia); Cebolla, V. [Instituto de Carboquimica, CSIC, Zaragoza (Spain)

    2002-10-01

    The copyrolysis of wood biomass-polyolefins was carried out in a rotating autoclave. At 400C, more than 50% (in mass) of final products are found in the liquid phase for a 1:1 (in mass) mixture. The obtained liquids are separated in a distillable liquids fraction and in an extracted liquids fraction. The first fraction can be fully characterised by gas chromatography/mass spectrometry. Only olefins, paraffins and some aromatics (benzene, toluene and xylene), issued from the polymers, are found in this fraction. The origin of the polymer plays the most important role in the chemical composition of this fraction. Some interactions with the solid issued from thermal degradation of the biomass are evidenced, for example by the presence of 2-alkenes with 3n carbon atoms. In the heavy liquids fraction, more than 80% (in mass) of the products are heavy olefins or paraffins. Schematically, we can explain the results of the copyrolysis experiments by: the biomass, whatever its origin, leads to solid, water and gas; polymer leads to liquid and gaseous olefins and paraffins; at a temperature lower than 400C, the biomass reacts and during the pyrolysis at 400C the formed solid evolves to act as a radical donor; assisted by radicals from biomass, polymer chain scission leads to the production of the light liquids; if the presence of biomass has an influence on the chemical composition of final products (particularly the light liquids fraction) their origin has, in general, only a limited effect.

  3. Synthesis of polymer nanoparticles via vapor phase deposition onto liquid substrates.

    Science.gov (United States)

    Haller, Patrick D; Gupta, Malancha

    2014-12-01

    In this article, the growth of polymer nanoparticles formed at the liquid-vapor interface via vapor phase polymerization is studied. The particles grow by polymer aggregation, which is driven by the surface tension interaction between the liquid and polymer. It is demonstrated that the mechanism of particle growth is determined by whether polymer particles remain at the liquid-vapor interface or submerge into the liquid. The position of the particles depends on the interaction between the polymer and the liquid. For example, the deposition of poly(n-butyl acrylate) onto poly(dimethyl siloxane) and Krytox liquids leads to the formation of nanoparticles that remain at the liquid-vapor interface. The size of these particles increases as a function of deposition time. The deposition of poly(4-vinylpyridine) onto poly(dimethyl siloxane) and Krytox leads to the formation of nanoparticles that submerge into the liquid. The size of these particles does not significantly change with deposition time. Our study offers a new rapid, one-step synthetic approach for fabricating functional polymer nanoparticles for applications in catalysis, photonics, and drug delivery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Morphology effect on the light scattering and dynamic response of polymer network liquid crystal phase modulator.

    Science.gov (United States)

    Xiangjie, Zhao; Cangli, Liu; Jiazhu, Duan; Jiancheng, Zeng; Dayong, Zhang; Yongquan, Luo

    2014-06-16

    Polymer network liquid crystal (PNLC) was one of the most potential liquid crystal for submillisecond response phase modulation, which was possible to be applied in submillisecond response phase only spatial light modulator. But until now the light scattering when liquid crystal director was reoriented by external electric field limited its phase modulation application. Dynamic response of phase change when high voltage was applied was also not elucidated. The mechanism that determines the light scattering was studied by analyzing the polymer network morphology by SEM method. Samples were prepared by varying the polymerization temperature, UV curing intensity and polymerization time. The morphology effect on the dynamic response of phase change was studied, in which high voltage was usually applied and electro-striction effect was often induced. The experimental results indicate that the polymer network morphology was mainly characterized by cross linked single fibrils, cross linked fibril bundles or even both. Although the formation of fibril bundle usually induced large light scattering, such a polymer network could endure higher voltage. In contrast, although the formation of cross linked single fibrils induced small light scattering, such a polymer network cannot endure higher voltage. There is a tradeoff between the light scattering and high voltage endurance. The electro-optical properties such as threshold voltage and response time were taken to verify our conclusion. For future application, the monomer molecular structure, the liquid crystal solvent and the polymerization conditions should be optimized to generate optimal polymer network morphology.

  5. Sodium carbonate as phase promoter in aqueous solutions of imidazolium and pyridinium ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Deive, Francisco J. [Chemical Engineering Department, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Rivas, Miguel A. [Applied Physics Department, University of Vigo, 36310 Vigo (Spain); Rodriguez, Ana, E-mail: aroguez@uvigo.es [Chemical Engineering Department, University of Vigo, 36310 Vigo (Spain)

    2011-08-15

    Highlights: > The discovery of novel aqueous two-phase systems, exclusively formed by the mixture of an ionic liquid and sodium carbonate is presented. > We explore for the first time the ability of pyridinium-based ionic liquids to form aqueous biphasic systems. > A first advance of the benefits of using benzylimidazolium-based ionic liquids for aqueous two-phase systems is proposed. - Abstract: Several methylsulfate and chloride anion-based ionic liquids, such as 1-alkyl-3-methyl imidazolium methyl sulfate, C{sub n}MIM CH{sub 3}SO{sub 4} (n = 1, 2, and 4), 1-benzyl-3-methyl imidazolium methyl sulfate, BzMIM CH{sub 3}SO{sub 4}, 1-benzyl, or hexyl-3-methyl imidazolium chloride, XMIM Cl (X = Bz and Hx), and methylpyridinium methylsulfate, Mpy CH{sub 3}SO{sub 4}, with sodium carbonate, Na{sub 2}CO{sub 3}, as phase forming salt, have been investigated and discussed for their potential use in separations based on aqueous two-phase systems (ATPS). Phase diagrams have been experimentally ascertained at T = 298.15 K, and Merchuck equation and a variation of this model have been used for correlating the binodal data. The alkyl chain length in the cation and the type of anion and cation have been explored and discussed due to their decisive influence in the ATPS behavior. The consistence of tie-line data was ascertained by applying the Othmer-Tobias and Bancroft equations.

  6. Dielectric properties and molecular motions of liquid crystal molecules in 4-(2-methylbytylphenyl 4-(4-octylphenylbenzoate liquid crystal having blue phase (CE8

    Directory of Open Access Journals (Sweden)

    Otowski W.

    2015-06-01

    Full Text Available Blue phase liquid crystals exhibit unique properties which are used in the new type of display. A blue-phase liquid crystal display was first presented commercially by Samsung in 2007. The blue-phase-three-color pixel display eliminates the need for color filters. This type of display uses blue-phase multi-component liquid crystal. Considering the one-component systems, it turns out that they are stable only in a very narrow range of temperatures between the isotropic and the chiral nematic phase (about 1 K. In 2005, a wide temperature range BP multi-component system was reported by researchers from the University of Cambridge. There are still several unsolved problems left. One of them is chemical stability and reliability. Therefore, the knowledge of molecular dynamics of blue phase liquid crystal is a prerequisite for understanding of blue-phase multi-component system. Understanding the molecular dynamics of a single component liquid-crystalline blue phase system can facilitate the solution of these problems. We present the molecular dynamics investigation of 4-(2-methylbytylphenyl 4-(4-octylphenylbenzoate (CE8, which may be a good candidate to form materials suitable for blue-phase liquid crystal displays.

  7. X-ray spectroscopy of chemical systems in liquids phase

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Zhong; Kubicek, Katharina [Max Planck Institute for Biophysical Chemistry, Goettingen (Germany); Deutsches Elektronen Synchrotron DESY, Hamburg (Germany); Techert, Simone; Rajkovic, Ivan [Max Planck Institute for Biophysical Chemistry, Goettingen (Germany); Foehlisch, Alexander [Helmholtz Zentrum Berlin, Berlin (Germany); University of Potsdam (Germany); Wernet, Philippe; Quevedo, Wilson [Helmholtz Zentrum Berlin, Berlin (Germany)

    2013-07-01

    Based on their ability to salt in or salt out macromolecules salt ions are classified according to the Hofmeister series. While the macroscopic effect is known for over 100 years, the origin of the effect on the molecular level is still not understood. We present X-ray emission spectroscopy (XES) on the oxygen K-edge of water in aqueous solutions of inorganic salts using BESSY II synchrotron (Berlin, Germany) X-rays. The FlexRIXS end station utilized a liquid micro jet for sample delivery. The element- and site-specific XES method contains information about occupied and unoccupied molecular orbitals and is therefore sensitive to the chemical environment. The aim of our measurements was to reveal the influence of the water-ion interactions on the local water structure further elucidating the understanding of the structure maker and structure breaker concept. Structural changes while utilizing different salts were expected to show as spectral changes in the oxygen K-edge spectra, e.g. of peak shapes or intensities.

  8. Liquid flyback booster pre-phase: A study assessment

    Science.gov (United States)

    Peterson, W.; Ankney, W.; Bell, J.; Berning, M.; Bryant, L.; Bufkin, A.; Cain, L.; Caram, J.; Cockrell, B.; Curry, D.

    1994-09-01

    The concept of a flyback booster has been around since early in the shuttle program. The original two-stage shuttle concepts used a manned flyback booster. These boosters were eliminated from the program for funding and size reasons. The current shuttle uses two Redesigned Solid Rocket Motors (RSRM's), which are recovered and refurbished after each flight; this is one of the major cost factors of the program. Replacement options have been studied over the past ten years. The conclusion reached by the most recent study is that the liquid flyback booster (LFBB) is the only competitive option from a life-cycle cost perspective. The purpose of this study was to assess the feasibility and practicality of LFBB's. The study provides an expansion of the recommendations made during the aforementioned study. The primary benefits are the potential for enhanced reusability and a reduction of recurring costs. The potential savings in vehicle turnaround could offset the up-front costs. Development of LFBB's requires a commitment to the shuttle program for 20 to 30 years. LFBB's also offer enhanced safety and abort capabilities. Currently, any failure of an RSRM can be considered catastrophic, since there are no intact abort capabilities during the burn of the RSRM's. The performance goal of the LFBB's was to lift a fully loaded orbiter under optimal conditions, so as not to be the limiting factor of the performance capability of the shuttle. In addition, a final benefit is the availability of growth paths for applications other than shuttle.

  9. Reversed-phase liquid chromatography and argentation chromatography of the minor capsaicinoids.

    Science.gov (United States)

    Thompson, Robert Q; Phinney, Karen W; Sander, Lane C; Welch, Michael J

    2005-04-01

    An investigation of the liquid chromatography of the minor capsaicinoids in a commercial capsaicinoid mixture is reported. Twelve stationary phases including C8, C18, C30, phenyl, and cation-exchange chemistries were examined in combination with isocratic aqueous methanol and aqueous acetonitrile mobile phases. A phenyl stationary phase and aqueous acetonitrile mobile phase baseline-resolved 7 of 11 capsaicinoids, and selected ion chromatograms (LC-ESI-MS) demonstrated this was the most effective reversed-phase separation. Argentation chromatography with an alkyl or phenyl column and aqueous silver nitrate-methanol mobile phase revealed the presence of the 6-ene-8-methyl and 6-ene-9-methyl homocapsaicin isomers and the absence of 7-ene-9-methyl homocapsaicin. A mixed phenyl-cation-exchange stationary phase (charged with silver ion) enabled unique and useful separations of the capsaicinoids.

  10. Solute NMR study of a bimesogenic liquid crystal with two nematic phases

    Science.gov (United States)

    Dong, R. Y.; Kohlmeier, A.; Tamba, M. G.; Mehl, G. H.; Burnell, E. E.

    2012-11-01

    Recent interest in bimesogenic liquid crystals showing two nematic phases has led us to investigate the nematic mean-field interactions in these nematic phases by using rigid solutes as probes. The nematic potential that is modelled by two independent Maier-Saupe terms is successful in fitting the observed dipolar couplings (molecular order parameters) of para-, meta- and ortho-dichlorobenzene solutes in both nematic phases of 39 wt.% 4-n-pentyl-4'-cyanobiphenyl (5CB) in α,ω-bis (4-4'-cyanobiphenyl) nonane (CBC9CB) to better than the 5% level. The derived liquid-crystal potential parameters G1 and G2 for each solute in the N and Nx phases are discussed.

  11. Anomalous partitioning of water in coexisting liquid phases of lipid multilayers near 100% relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yicong; Ghosh, Sajal K.; Bera, Sambhunath; Jiang, Zhang; Schlepütz, Christian M.; Karapetrova, Evguenia; Lurio, Laurence B.; Sinha, Sunil K.

    2015-11-30

    X-ray diffraction is used to determine the hydration dependence of a ternary mixture lipid multilayer structure which has phase separated into liquid-ordered (Lo) and liquid-disordered (Ld) phases. An anomaly is observed in the swelling behavior of the Ld phase at a relative humidity (RH) close to 100%, which is different from the anomalous swelling happens close to the main lipid gel-fluid transition. The lamellar repeat distance of the Ld phase swells by an extra 4 Å, well beyond the equilibrium spacing predicted by the inter-bilayer forces. This anomalous swelling is caused by the hydrophobic mismatch energy at the domain boundaries, which produces surprisingly long range effect.

  12. Pattern phase transitions of self-propelled particles: gases, crystals, liquids, and mills

    Science.gov (United States)

    Cheng, Zhao; Chen, Zhiyong; Vicsek, Tamás; Chen, Duxin; Zhang, Hai-Tao

    2016-10-01

    To understand the collective behaviors of biological swarms, flocks, and colonies, we investigated the non-equilibrium dynamic patterns of self-propelled particle systems using statistical mechanics methods and H-stability analysis of Hamiltonian systems. By varying the individual vision range, we observed phase transitions between four phases, i.e., gas, crystal, liquid, and mill-liquid coexistence patterns. In addition, by varying the inter-particle force, we detected three distinct milling sub-phases, i.e., ring, annulus, and disk. Based on the coherent analysis for collective motions, one may predict the stability and adjust the morphology of the phases of self-propelled particles, which has promising potential applications in natural self-propelled particles and artificial multi-agent systems.

  13. Traceless liquid-phase synthesis of biphenyls and terphenyls using pentaerythritol as a tetrapodal soluble support.

    Science.gov (United States)

    Kim, Chul-Bae; Cho, Chul-Hee; Kim, Chang Keun; Park, Kwangyong

    2007-01-01

    Application of a novel sulfonate-based traceless multifunctional linker system using pentaerythritol as a tetrapodal soluble support was demonstrated using liquid-phase parallel and combinatorial preparation of biphenyl and terphenyl compounds. Nickel-catalyzed reactions of pentaerythritol tetrakis(arenesulfonate)s with arylmagnesium bromides generated the desired products in sufficient yields through reductive cleavage/cross-coupling of the C-S bond. Homogeneous pentaerythritol-supported reactions could be accomplished using less nucleophile with shorter reaction periods than could the corresponding heterogeneous polymer-supported reactions. This liquid-phase approach using a small polyfunctionalized support combines advantages of solution-phase and solid-phase syntheses by allowing high reactivity, high atom economy, simple isolation, and real-time monitoring of the reaction progress.

  14. Formation of metastabil liquid phases in the isotonic solution of sodium cloraide during cooling

    Directory of Open Access Journals (Sweden)

    A. T. Ходько

    2016-07-01

    Full Text Available In this paper the cooling process cryomicroscopy of 0.15 M of isotonic sodium chloride solution was conducted. It was shown that there is liquidliquid phase change before the crystallization process. As a result, the coarse system (highly concentrated emulsion was formed. The dispersed phase and the disperse medium in a binary system with the same qualitative chemical composition differ in concentration. Therefore, the greater is the volume ratio of the coexisting phases, the greater is the difference in their quantitative compositions. The dispersed phase, that composes the main volume in the system under investigation, should have lower NaCl concentration than the disperse medium and the initial solution. In this case it will be hypotonic (and disperse medium – hypertonic in relation to cytoplasm of human internal environment. This physical-chemical factor, which hasn’t been considered previously, might be responsible for osmotic damage in living cells during cryopreservation of cell suspensions.

  15. Liquid phase sintering, I: Computer study of skeletal settling and solid phase extrication in a normal gravity environment

    Directory of Open Access Journals (Sweden)

    Nikolić Z.S.

    2008-01-01

    Full Text Available In this paper we will investigate gravity induced skeletal settling during liquid phase sintering. In this approach skeletal settling will be combined with extrication of some solidphase domains. The main goal will be the need to relate dissolution, diffusion and precipitation phenomena to essential geometric and topological changes of the tungstennickel porous microstructure influenced by differential skeletal settling due to large density difference between tungsten domains and the matrix. This study will be based on domain topology (no shape restriction and control-volume methodology. The microstructural evolution will be simulated by computation of displacement of the center of mass (combined gravity induced settling and random motion and mass transport due to dissolution and precipitation at the interfaces between solid-phase and liquid matrix.

  16. Determination of erythromycins in fermentation broth using liquid phase extraction with back extraction combined with high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Fahimeh Kamarei

    2014-07-01

    Full Text Available Liquid phase extraction with back extraction (LPE-BE combined with high performance liquid chromatography-diode array detection (HPLC-DAD was applied for the extraction and determination of erythromycin A, B and C in fermentation broths. According to this procedure, the fermentation broth with the adjustment pH at a fixed value of 10 was first mixed with organic solvent (Vbroth/Vorg = 1.0. After shaking, the mixture was separated into two phases by microfuging at 13,000 rpm for 15 min. Then back extraction was performed into the acidic aqueous phase with pH 5.0 (Vorg/Vaq = 1.0. After centrifugation at 3000, the two phases were separated and 50 μL of the acidic aqueous phase was injected into the HPLC. The effects of different variables such as the nature of extraction solvent and the pH of samples and buffer were investigated. At the most appropriate conditions, dynamic linear ranges of 0.5–8, 0.1–0.9 and 0.1–0.9 mg mL−1 and limits of detection of 0.03, 0.003 and 0.002 mg mL−1 were obtained for erythromycin A, B and C, respectively. Relative standard deviations (RSDs of the proposed method were less than 9.5%. The mean recoveries were 99.5%. The proposed method is simple and sensitive with highly clean-up effect and it can be used for monitoring the progress of erythromycin fermentation.

  17. Phase behavior of chromonic liquid crystal mixtures of Sunset Yellow and Disodium Cromoglycate

    Science.gov (United States)

    Yamaguchi, Akihiro; Smith, Gregory; Yi, Youngwoo; Xu, Charles; Biffi, Silvia; Serra, Francesca; Bellini, Tommaso; Clark, Noel

    2014-03-01

    Chromonic liquid crystals (CLCs) are formed when planar molecules dissolved in water stack into rod-like aggregates that can order as liquid crystals. Isotropic, nematic, and M-phases can be observed depending on the degree of molecular orientational and positional order by variation of the CLC concentration. We focused on mixtures of two well-known CLCs, Sunset Yellow, a food dye, and disodium cromoglycate (DSCG), an asthma medication. In order to study the phase behaviors of these mixtures, we observed their textures in glass cells and capillaries using polarized light microscopy. We report here a ternary phase diagram describing the complete phase behavior of the CLC mixtures. We observed a variety of phase behaviors depending on species ratio and concentration. In the isotropic phase, no clear phase separation of the two dyes was observed, while separation did occur in many nematic and M-phase combinations. We will also describe phase observations made using a light spectroscopy and bulk centrifugal partitioning. Grant support: NSF DMR 1207606 and NSF MRSEC DMR-0820579.

  18. Cation-exchange solid-phase and liquid-liquid extraction for the determination of khat alkaloids by reversed phase HPLC-DAD

    Directory of Open Access Journals (Sweden)

    M. Atlabachew

    2015-10-01

    Full Text Available Leaves of khat (Catha edulis are masticated to elicit their psycho-stimulating properties, resulting from the presence of the phenylpropylamino alkaloids. The determination of these alkaloids is important in pharmacological, phytochemical, forensic and law enforcement environments. In this study, the use of strong cation exchange-solid phase extraction (SCX-SPE was investigated as an alternative means of sample purification prior to the determination of cathinone, cathine and norephedrine by reversed phase (C18 high performance liquid chromatography (HPLC. Extraction parameters for SCX, including loading capacity and washing solvents, were established. An existing liquid-liquid extraction (LLE method was improved in terms of recoveries obtained, by using ethyl acetate as extractant. For pure standards of the khat alkaloids, recoveries ranged from 83 to 97%. Preconcentration, using a Genevac evaporator after the addition of acidified water to the sample, restricted analyte losses when compared to concentration under nitrogen. Although comparable recoveries were obtained when preconcentration was achieved in the presence of acidified water by rotary evaporation, this method is not suitable for large sample numbers. Best recoveries, ranging from 94 to 102%, were obtained by SCX from spiked samples. Although the extraction efficiencies of LLE were lower (87-90%, LLE yielded less complex chromatograms, indicating a purer extract.DOI: http://dx.doi.org/10.4314/bcse.v29i3.1

  19. Copper Containing Silicates as Catalysts for Liquid Phase Cyclohexane Oxidation

    Directory of Open Access Journals (Sweden)

    Cruz Rosenira S. da

    2002-01-01

    Full Text Available Copper containing silicates have been prepared by an acid-catalyzed sol-gel process. The materials were characterized by X-ray diffraction and fluorescence, EPR spectroscopy, elemental analysis, N2-physisorption, thermogravimetry, differential scanning calorimetry, temperature-programmed reduction, FTIR and UV/VIS spectroscopy. The silicates were shown to be efficient catalysts for the oxidation of cyclohexane with tert-butyl hydroperoxide as oxidant. Cyclohexanol and cyclohexanone were obtained as the main products. The metal was shown to be weakly bound to the silicate matrix and metal leaching was observed. Leaching was quantified by X-ray fluorescence and leaching tests showed that the catalytic activity is due to supported copper species. Leached copper showed no activity in the homogeneous phase.

  20. Evidence of a liquid–liquid phase transition in hot dense hydrogen

    OpenAIRE

    Dzyabura, Vasily; Zaghoo, Mohamed; Silvera, Isaac F.

    2013-01-01

    We use pulsed-laser heating of hydrogen at static pressures in the megabar pressure region to search for the plasma phase transition to liquid atomic metallic hydrogen. We heat our samples substantially above the melting line and observe a plateau in a temperature vs. laser power curve that otherwise increases with power. This anomaly in the heating curve appears correlated with theoretical predictions for the plasma phase transition.

  1. Functional design criteria for project W-252, phase II liquid effluent treatment and disposal. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    Hatch, C.E.

    1995-05-01

    This document is the Functional Design Criteria for Project W-252. Project W-252 provides the scope to provide BAT/AKART (best available technology...) to 200 Liquid Effluent Phase II streams (B-Plant). This revision (Rev. 2) incorporates a major descoping of the project. The descoping was done to reflect a combination of budget cutting measures allowed by a less stringent regulatory posture toward the Phase II streams

  2. Electrically controlled phases of partially polarized light and orientational Kerr effect in liquid crystal ferroelectrics

    Directory of Open Access Journals (Sweden)

    Kiselev Alexei D.

    2017-01-01

    Full Text Available We study the electro-optic properties of subwavelength-pitch deformed-helix ferroelectric liquid crystals illuminated with partially polarized light. In an experimental setup based on the Mach-Zehnder interferometer, it is found that the interference pattern crucially depends on the degree of polarization of the incident light. We evaluate the electric field dependence of both the Pancharatnam relative phase and the geometric phase for the general case of nonunitarily evolving mixed polarization states.

  3. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, July-September 1984

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1984-10-30

    Work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. Calorimetric measurements were made on pure quinoline. These measurements extended the range of previous measurements which had been made on quinoline, and improved the accuracy of previously measured results in the vapor phase when the quinoline sample used was believed to contain considerable quantities of water. 5 figures, 4 tables.

  4. Density functional theory of gas-liquid phase separation in dilute binary mixtures.

    Science.gov (United States)

    Okamoto, Ryuichi; Onuki, Akira

    2016-06-22

    We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference of the solvation chemical potential between liquid and gas [Formula: see text] (the Gibbs energy of transfer) is considerably larger than the thermal energy [Formula: see text] for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by [Formula: see text], where [Formula: see text] is the solute density added in liquid. For [Formula: see text], phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, even when the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.

  5. Simulation of plasma discharge in liquids: A detailed two-phase fluid approach

    Science.gov (United States)

    Charchi Aghdam, Ali; Farouk, Tanvir; Reacting Systems; Advanced Energy Research Laboratory Team

    2015-09-01

    Plasma discharge in liquids has gained great attention recently due to its applications in biomedical engineering, fuel processing, and water treatment and so on. Despite the tremendous interest, a comprehensive understanding of the underlying physics still remains limited. In the current work, an attempt is made to present a mathematical multi-physics model to describe the discharge of plasma in liquids. An in-house modeling platform is developed for simulating plasma formation in multiphase fluids. The model resolves a detailed two-phase fluid including viscous effects, surface tension, gravitational forces and electrical body force. All the governing equations are solved for gas and liquid phases. Electric field and charged species equations along with the plasma reaction kinetics are solved to get the charge distribution in the different phases as well as at the gas-liquid interface to obtain the electric body force acting at the interface. By coupling the above sub-models, a comprehensive multi-physics model for plasma discharge in liquids is constructed which is able to capture several physical aspects of the phenomena especially the role of the bubble, its motion and distortion on plasma characteristics.

  6. Phase equilibrium properties of coal-derived liquids. Technical progress report, July-December 1980

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1981-01-01

    A wide variety of methods have been used to study the phase behavior of mixtures, including: Measuring the phase boundary of binary mixtures, observing property discontinuities from volumetric measurements, and thermal measurements of mixtures, measuring the composition of samples in batch systems, measuring the composition of samples from continuous remixing and separation in recirculating systems, gas-liquid chromatography, and measuring the composition of samples from a once-through flow system. A major difficulty associated with measuring phase behavior of complex mixtures is the need to characterize the vapor and liquid sample products. This generally requires the collection of considerable quantities of the liquid and vapor products. Of all the methods listed, the only method which can generate significant quantities of both liquid and vapor products is the once-through flow method. This method has been used previously in determining the K values for petroleum fractions. For these reasons, we have designed a flow equilibrium flash vaporization system similar to the ones previously used on petroleum liquids.

  7. Liquid-liquid phase separation in dilute solutions of poly(styrene sulfonate) with multivalent cations: Phase diagrams, chain morphology, and impact of temperature.

    Science.gov (United States)

    Hansch, Markus; Hämisch, Benjamin; Schweins, Ralf; Prévost, Sylvain; Huber, Klaus

    2018-01-07

    The dilute solution behavior of sodium poly(styrene sulfonate) is studied in the presence of trivalent Al3+ and bivalent Ba2+ cations at various levels of excess NaCl. The study evaluates the phase behavior and the morphology of the polyelectrolyte chains with increasing extent of decoration with the Al3+ and Ba2+ cations and analyses the effect of temperature on these decorated chains. The phase behavior is presented in the form of the cation concentration versus the respective poly(styrene sulfonate) concentration, recorded at the onset of precipitation. Whereas poly(styrene sulfonate) with Al3+ exhibits a linear phase boundary, denoted as the "threshold line," which increases with increasing poly(styrene sulfonate) concentration, Ba2+ cations show a threshold line which is independent of the poly(styrene sulfonate) concentration. An additional re-entrant phase, at considerably higher cation content than those of the threshold lines, is observed with Al3+ cations but not with Ba2+ cations. The threshold line and the re-entrant phase boundary form parts of the liquid-liquid phase boundary observed at the limit of low polymer concentration. The dimensions of the polyelectrolyte chains shrink considerably while approaching the respective threshold lines on increase of the Al3+ and Ba2+ cation content. However, subtle differences occur between the morphological transformation induced by Al3+ and Ba2+. Most strikingly, coils decorated with Al3+ respond very differently to temperature variations than coils decorated with Ba2+ do. As the temperature increases, the poly(styrene sulfonate) chains decrease their size in the presence of Al3+ cations but increase in size in the presence of Ba2+ cations.

  8. Relation between the Widom Line and the Dynamic Crossover in Systems with a Liquid-Liquid Phase Transition

    National Research Council Canada - National Science Library

    Limei Xu; Pradeep Kumar; S. V. Buldyrev; S. -H. Chen; P. H. Poole; F. Sciortino; H. E. Stanley

    2005-01-01

    We investigate, for two water models displaying a liquid-liquid critical point, the relation between changes in dynamic and ther-modynamic anomalies arising from the presence of the liquid-liquid critical point...

  9. Phase equilibria of didecyldimethylammonium nitrate ionic liquid with water and organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula [Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)]. E-mail: ula@ch.pw.edu.pl; Lugowska, Katarzyna [Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Pernak, Juliusz [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland)

    2007-05-15

    The phase diagrams for binary mixtures of an ammonium ionic liquid, didecyldimethylammonium nitrate, [DDA][NO{sub 3}], with: alcohols (propan-1-ol, butan-1-ol, octan-1-ol, and decan-1-ol): hydrocarbons (toluene, propylbenzene, hexane, and hexadecane) and with water were determined in our laboratory. The phase equilibria were measured by a dynamic method from T 220 K to either the melting point of the ionic liquid, or to the boiling point of the solvent. A simple liquidus curve in a eutectic system was observed for [DDA][NO{sub 3}] with: alcohols (propan-1-ol, butan-1-ol, and octan-1-ol); aromatic hydrocarbons (toluene and propylbenzene) and with water. (Solid + liquid) equilibria with immiscibility in the liquid phase were detected with the aliphatic hydrocarbons heptane and hexadecane and with decan-1-ol. (Liquid + liquid) equilibria for the system [DDA][NO{sub 3}] with hexadecane was observed for the whole mole fraction range of the ionic liquid. The observation of the upper critical solution temperature in binary mixtures of ([DDA][NO{sub 3}] + decan-1-ol, heptane, or hexadecane) was limited by the boiling temperature of the solvent. Characterisation and purity of the compounds were determined by elemental analysis, water content (Fisher method) and differential scanning microcalorimetry (d.s.c.) analysis. The d.s.c. method of analysis was used to determine melting temperatures and enthalpies of fusion. The thermal stability of the ionic liquid was resolved by the thermogravimetric technique-differential thermal analysis (TG-DTA) technique over a wide temperature range from (200 to 780) K. The thermal decomposition temperature of 50% of the sample was greater than 500 K. The (solid + liquid) phase equilibria, curves were correlated by means of different G {sup Ex} models utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular

  10. A method for the analysis of six thyroid hormones in thyroid gland by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kunisue, Tatsuya; Fisher, Jeffrey W; Fatuyi, Babatope; Kannan, Kurunthachalam

    2010-07-01

    Perchlorate can competitively inhibit iodide uptake by the thyroid gland (TG) via the sodium/iodide symporter, consequently reducing the production of thyroid hormones (THs). Until recently, the effects of perchlorate on TH homeostasis are being examined through measurement of serum levels of TH, by immunoassay (IA)-based methods. IA methods are fast, but for TH analysis, they are compromised by the lack of adequate specificity. Therefore, selective and sensitive methods for the analysis of THs in TG are needed, for assessment of the effects of perchlorate on TH homeostasis. In this study, we developed a method for the analysis of six THs: L-thyroxine (T(4)), 3,3',5-triiodo-L-thyronine (T(3)), 3,3',5'-triiodo-L-thyronine (rT(3)), 3,5-diiodo-L-thyronine (3,5-T(2)), 3,3'-diiodo-L-thyronine (3,3'-T(2)), and 3-iodo-L-thyronine (3-T(1)) in TG, using liquid chromatography (LC)-tandem mass spectrometry (MS/MS). TGs used in this study were from rats that had been placed on either iodide-deficient diet or iodide-sufficient diet, and that had either been provided with perchlorate in drinking water (10 mg/kg/day) or control water. TGs were extracted by pronase digestion and then analyzed by LC-MS/MS. The instrumental calibration range for each TH ranged from 1 to 200 ng/ml and showed a high linearity (r>0.99). The method quantification limits (LOQs) were determined to be 0.25 ng/mg TG for 3-T(1); 0.33 ng/mg TG for 3,3'- and 3,5-T(2); and 0.52 ng/mg TG for rT(3), T(3), and T(4). Rats were placed on an iodide-deficient or -sufficient diet for 2.5 months, and for the last 2 weeks of that period were provided either perchlorate (10 mg/kg/day) in drinking water or control water. Iodide deficiency and perchlorate administration both reduced TG stores of rT(3), T(3), and T(4). In iodide-deficient rats, perchlorate exacerbated the reduction in levels of THs in TG. With the advances in analytical methodology, the use of LC-MS/MS for measurement of hormone levels in TG will allow more

  11. Liquid-liquid extraction of enzymes by affinity aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    Xu Yan

    2003-12-01

    Full Text Available From analytical to commercial scale, aqueous two-phase systems have their application in the purification, characterization and study of biomaterials. In order to improve the selectivity of the systems, the biospecific affinity ligands were introduced. In the affinity partitioning aqueous two-phase system, have many enzymes been purified. This review discusses the partitioning of some enzymes in the affinity aqueous two-phase systems in regard to the different ligands, including reactive dyes, metal ions and other ligands. Some integration of aqueous two-phase system with other techniques for more effective purification of enzymes are also presented.Tanto em escala de laboratório como industrial, os sistemas de duas fases aquosas podem ser utilizados para a purificação, caracterização e estudos de biomateriais. Para aumentar a seletividade desse sistema, ligantes de afinidade bioespecíficos podem ser utilizados. No sistema de duas fases aquosas por afinidade, muitas enzimas podem ser purificadas. Neste artigo de revisão, a partição de algumas enzimas por esse tipo de afinidade, utilizando diferentes ligantes como corantes e íons metálicos, são discutidas. Além disso, a integração desse sistema de duas fases aquosas com outras técnicas de purificação estão sendo apresentados, com o objetivo mostrar a melhoria da eficiência do processo.

  12. Sorption of catechins under conditions of reverse-phase high-efficiency liquid chromatography

    Science.gov (United States)

    Shafigulin, R. V.; Egorova, K. V.; Bulanova, A. V.

    2010-08-01

    The physico-chemical principles of catechin sorption from various polar solvents onto silica gel modified with octadecyl groups were studied. Thermodynamic characteristics of the sorption were calculated, and the applicability of different models of retention was demonstrated for catechins under the conditions of reverse-phase high-efficiency liquid chromatography.

  13. Simplified thermodynamic functions for vapor-liquid phase separation and fountain effect pumps

    Science.gov (United States)

    Yuan, S. W. K.; Hepler, W. A.; Frederking, T. H. K.

    1984-01-01

    He-4 fluid handling devices near 2 K require novel components for non-Newtonian fluid transport in He II. Related sizing of devices has to be based on appropriate thermophysical property functions. The present paper presents simplified equilibrium state functions for porous media components which serve as vapor-liquid phase separators and fountain effect pumps.

  14. Liquid-phase reforming and hydrodeoxygenation as a two-step route to aromatics from lignin

    NARCIS (Netherlands)

    Jongerius, A.L.; Bruijnincx, P.C.A.; Weckhuysen, B.M.

    2013-01-01

    A two-step approach to the conversion of organosolv, kraft and sugarcane bagasse lignin to monoaromatic compounds of low oxygen content is presented. The first step consists of lignin depolymerization in a liquid phase reforming (LPR) reaction over a 1 wt% Pt/γ-Al2O3 catalyst at 225 °C in alkaline

  15. Highly Selective Liquid-Phase Benzylation of Anisole with Solid-Acid Zeolite Catalysts

    DEFF Research Database (Denmark)

    Poreddy, Raju; Shunmugavel, Saravanamurugan; Riisager, Anders

    2015-01-01

    Zeolites were evaluated as solid acid catalysts for the liquid-phase benzylation of anisole with benzyl alcohol, benzyl bromide, and benzyl chloride at 80 °C. Among the examined zeolites, H-mordenite-10 (H-MOR-10) demonstrated particular high activity (>99 %) and excellent selectivity (>96...

  16. Dynamic simulation of dispersed gas-liquid two-phase flow using a discrete bubble model.

    NARCIS (Netherlands)

    Delnoij, E.; Lammers, F.A.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1997-01-01

    In this paper a detailed hydrodynamic model for gas-liquid two-phase flow will be presented. The model is based on a mixed Eulerian-Lagrangian approach and describes the time-dependent two-dimensional motion of small, spherical gas bubbles in a bubble column operating in the homogeneous regime. The

  17. Absence of a spin liquid phase in the Hubbard model on the honeycomb lattice

    National Research Council Canada - National Science Library

    Sorella, Sandro; Otsuka, Yuichi; Yunoki, Seiji

    2012-01-01

    .... Very recently, it has been reported that a model of graphene, i.e., the Hubbard model on the honeycomb lattice, can show a spin liquid ground state in a wide region of the phase diagram, between a semi-metal (SM...

  18. Aquitard contaminant storage and flux resulting from dense nonaqueous phase liquid source zone dissolution and remediation

    Science.gov (United States)

    A one-dimensional diffusion model was used to investigate the effects of dense non-aqueous phase liquid (DNAPL) source zone dissolution and remediation on the storage and release of contaminants from aquitards. Source zone dissolution was represented by a power-law source depleti...

  19. Separable interactions and liquid 3He : V. Phase diagram in the presence of a Hubbard interaction

    NARCIS (Netherlands)

    Capel, H.W.; Nijhoff, F.W.; Breems, A. den

    1986-01-01

    A comparison is made between the various extrema of the Landau expansion of liquid 3He derived in a previous paper. As an application the phase diagram is investigated in the presence of an external magnetic field assuming that the Hubbard interaction is small as compared to the pairing interaction

  20. Residence time distribution of the gas phase in a mechanically agitated gas-liquid reactor

    NARCIS (Netherlands)

    Thijert, M.P.G.; Oyevaar, M.H.; Kuper, W.J.; Westerterp, K.R.

    1992-01-01

    In this study we present a measuring method and extensive experimental data on the gas phase RTD in a mechanically agitated gas-liquid reactor with standard dimensions over a wide range of superficial gas velocities, agitation rates and agitator sizes. The results are modelled successfully, using

  1. Liquid-phase oxidation of naphthalene with in the presence of ...

    Indian Academy of Sciences (India)

    Zhiwei Zhou

    Abstract. The ordered mesoporous V-m-Al2O3 catalysts were successfully synthesized via a facile one-pot evaporation-induced self-assembly (EISA) strategy and applied in the liquid-phase oxidation of naphthalene with hydrogen peroxide in the presence of ascorbic acid as a reductant. The physicochemical properties of ...

  2. Entrainment phenomenon in gas–liquid two-phase flow: A review

    Indian Academy of Sciences (India)

    over in two-phase systems based on the experiments. Iyer et al (2010) .... Entrainment phenomenon in gas–liquid flows. 1179. T able. 1 . Summary of prev ious analytical w o rk. Geometrical parameters. Ph ysical. Properties. R ange. D. H. D i. D o. HH. M ...... Sterman L S 1958 On the theory of steam separation. Sovt. Phys.

  3. Improved thermal lattice Boltzmann model for simulation of liquid-vapor phase change

    Science.gov (United States)

    Li, Qing; Zhou, P.; Yan, H. J.

    2017-12-01

    In this paper, an improved thermal lattice Boltzmann (LB) model is proposed for simulating liquid-vapor phase change, which is aimed at improving an existing thermal LB model for liquid-vapor phase change [S. Gong and P. Cheng, Int. J. Heat Mass Transfer 55, 4923 (2012), 10.1016/j.ijheatmasstransfer.2012.04.037]. First, we emphasize that the replacement of ∇ .(λ ∇ T ) /∇.(λ ∇ T ) ρ cV ρ cV with ∇ .(χ ∇ T ) is an inappropriate treatment for diffuse interface modeling of liquid-vapor phase change. Furthermore, the error terms ∂t 0(T v ) +∇ .(T vv ) , which exist in the macroscopic temperature equation recovered from the previous model, are eliminated in the present model through a way that is consistent with the philosophy of the LB method. Moreover, the discrete effect of the source term is also eliminated in the present model. Numerical simulations are performed for droplet evaporation and bubble nucleation to validate the capability of the model for simulating liquid-vapor phase change. It is shown that the numerical results of the improved model agree well with those of a finite-difference scheme. Meanwhile, it is found that the replacement of ∇ .(λ ∇ T ) /∇ .(λ ∇ T ) ρ cV ρ cV with ∇ .(χ ∇ T ) leads to significant numerical errors and the error terms in the recovered macroscopic temperature equation also result in considerable errors.

  4. Liquid phase methanol LaPorte process development unit: Modification, operation, and support studies

    Energy Technology Data Exchange (ETDEWEB)

    1991-02-02

    This report consists of Detailed Data Acquisition Sheets for Runs E-6 and E-7 for Task 2.2 of the Modification, Operation, and Support Studies of the Liquid Phase Methanol Laporte Process Development Unit. (Task 2.2: Alternate Catalyst Run E-6 and Catalyst Activity Maintenance Run E-7).

  5. Modeling the Phase Behavior in Mixtures of Pharmaceuticals with Liquid or Supercritical Solvents

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Economou, Ioannis; Kontogeorgis, Georgios

    2009-01-01

    the phase behavior of mixtures of six pharmaceuticals (i.e., ibuprofen, ketoprofen, naproxen, benzoic acid, methyl paraben, and ethyl paraben). The pure fluid parameters of the studied pharmaceuticals were estimated using limited available experimental (or predicted) data on sublimation pressures, liquid...

  6. Liquid phase surface nitriding of Ti-6Al-4V pre-placed with chromium

    Energy Technology Data Exchange (ETDEWEB)

    Vahedi Nemani, Alireza, E-mail: alireza_vahedi@ut.ac.ir; Sohi, M. Heydarzadeh; Amadeh, A.A.; Ghaffari, Mahya

    2016-08-01

    In this study, liquid phase surface nitriding of Ti-6Al-4V was carried out by pre-placing of chromium powder on the substrate and subsequent Tungsten Inert Gas (TIG) surface melting. The effect of the application of low and high heat inputs on the microstructure, microhardness and wear resistance of the treated layers were studied. Surface alloying with chromium in a nitrogen containing atmosphere resulted in the formation of hard intermetallic compounds such as TiN, Cr{sub 2}N and TiCr{sub 2}. Moreover, the presence of beta stabilizer chromium together with the application of high heat input during surface treatment resulted in the presence of beta phase at room temperature. However, applying low heat input could not prevent transformation of beta to martensite. The hardness of the layers fabricated at high and low heat inputs were respectively 1050 and 1200 HV{sub 0.3} compared to average 280 HV{sub 0.3} for the as-received material. Liquid phase surface treatment of titanium at the aforementioned conditions improved the wear resistance. The lowest weight loss belonged to the specimen with the beta phase matrix. The formation of the fairly ductile bcc-β phase hindered crack nucleation during wear. The weight loss in this condition was 7 times lower than that of the base material. - Highlights: • Liquid phase surface nitriding of Ti-6Al-4V was carried out by TIG surface melting. • Cr powder was pre-placed on the surface as the beta stabilizer alloying element. • The treated layers were characterized by OM, SEM and X-ray diffraction pattern. • Hardness of the layers increased up to 3 times higher than that of the base alloy. • Liquid phase surface alloying improved the wear resistance.

  7. Calculation of liquid-liquid equilibrium of aqueous two-phase systems using a chemical-theory-based excess Gibbs energy model

    Directory of Open Access Journals (Sweden)

    Pessôa Filho P. A.

    2004-01-01

    Full Text Available Mixtures containing compounds that undergo hydrogen bonding show large deviations from ideal behavior. These deviations can be accounted for through chemical theory, according to which the formation of a hydrogen bond can be treated as a chemical reaction. This chemical equilibrium needs to be taken into account when applying stability criteria and carrying out phase equilibrium calculations. In this work, we illustrate the application of the stability criteria to establish the conditions under which a liquid-phase split may occur and the subsequent calculation of liquid-liquid equilibrium using a chemical-theory-modified Flory-Huggins equation to describe the non ideality of aqueous two-phase systems composed of poly(ethylene glycol and dextran. The model was found to be able to correlate ternary liquid-liquid diagrams reasonably well by simple adjustment of the polymer-polymer binary interaction parameter.

  8. Ionic liquid for high temperature headspace liquid-phase microextraction of chlorinated anilines in environmental water samples.

    Science.gov (United States)

    Peng, Jin-feng; Liu, Jing-fu; Jiang, Gui-bin; Tai, Chao; Huang, Min-jia

    2005-04-22

    Based on the non-volatility of room temperature ionic liquids (IL), 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) IL was employed as an advantageous extraction solvent for high temperature headspace liquid-phase microextraction (LPME) of chloroanilines in environmental water samples. At high temperature of 90 degrees C, 4-chloroaniline, 2-chloroaniline, 3,4-dichloroaniline, and 2,4-dichloroaniline were extracted into a 10 microl drop of [C4MIM][PF6] suspended on the needle of a high-performance liquid chromatography (HPLC) microsyringe held at the headspace of the samples. Then, the IL was injected directly into the HPLC system for determination. Parameters related to LPME were optimized, and high selectivity and low detection limits of the four chlorinated anilines were obtained because the extraction was performed at high temperature in headspace mode and the very high affinity between IL and chlorinated anilines. The proposed procedure was applied for the analysis of the real samples including tap water, river water and wastewater samples from a petrochemical plant and a printworks, and only 3,4-dichloroaniline was detected in the printworks wastewater at 88.2 microg l(-1) level. The recoveries for the four chlorinated anilines in the four samples were all in the range of 81.9-99.6% at 25 microg l(-1) spiked level.

  9. Nociceptive processing in women with premenstrual dysphoric disorder (PMDD): the role of menstrual phase and sex hormones.

    Science.gov (United States)

    Bartley, Emily J; Palit, Shreela; Kuhn, Bethany L; Kerr, Kara L; Terry, Ellen L; DelVentura, Jennifer L; Rhudy, Jamie L

    2015-04-01

    Premenstrual dysphoric disorder (PMDD) is associated with increased pain, but there has been a lack of well-controlled research assessing pain responsivity, sex hormones, and their relationships in this group. This study was designed to address this gap in the literature. Healthy, regularly cycling participants (14 PMDD, 14 non-PMDD) attended pain testing sessions during the mid-follicular, ovulatory, and late-luteal phases of the menstrual cycle (order counterbalanced) and salivary estradiol, progesterone, and testosterone were assessed at each testing session. Pain sensitivity was measured from electrocutaneous threshold/tolerance, ischemic threshold/tolerance, sensory and affective ratings of electrocutaneous and ischemic stimuli, and the nociceptive flexion reflex threshold (NFR, a measure of spinal nociception). Women with PMDD had higher sensory pain ratings of electrocutaneous stimuli and trends for lower ischemic thresholds and higher affective pain ratings of electrocutaneous stimuli. However, there were no group differences observed in NFR threshold. Testosterone levels were also lower during the mid-follicular and ovulatory phases in PMDD. Correlations between pain outcomes and estradiol and testosterone indicated that these hormones are hypoalgesic, with estradiol having a greater hypoalgesic effect within the PMDD group. Overall, women with PMDD may have a phase-independent hyperalgesia, with pain amplification likely occurring at the supraspinal level rather than the spinal level, given the lack of group differences in NFR threshold. Because testosterone was hypoalgesic and lower in women with PMDD, and there were strong associations between pain and estradiol in PMDD, sex hormones may play a role in PMDD-related hyperalgesia.

  10. Determination of antimony and tin in beverages using inductively coupled plasma-optical emission spectrometry after ultrasound-assisted ionic liquid dispersive liquid-liquid phase microextraction.

    Science.gov (United States)

    Biata, N Raphael; Nyaba, Luthando; Ramontja, James; Mketo, Nomvano; Nomngongo, Philiswa N

    2017-12-15

    The aim of this study was to develop a simple and fast ultrasound-assisted ionic liquid dispersive liquid-liquid phase microextraction (UA-IL-DLLME) method for preconcetration of trace antimony and tin in beverage samples. The novelty of this study was based on the application of ligandless UA-IL-DLLME using low-density ionic liquid and organic solvents for preconcentration of Sb and Sn. The concentration of Sb and Sn were quantified using ICP-OES. Under the optimum conditions, the calibration graph was found to be LOQ-250µgL(-1) (r(2)=0.9987) for Sb and LOQ-350µgL(-1) for Sn. The LOD and LOQ of Sb and Sn ranged from 1.2to 2.5ngL(-1) and 4.0 to 8.3ngL(-1), respectively, with high preconcentration factors. The precisions (%RSD) of the proposed method ranged from 2.1% to 2.5% and 3.9% to 4.7% for Sb and Sn, respectively. The proposed method was successfully applied for determination of Sb and Sn in beverages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Matrix solid-phase dispersion coupled with magnetic ionic liquid dispersive liquid-liquid microextraction for the determination of triazine herbicides in oilseeds.

    Science.gov (United States)

    Wang, Yuanpeng; Sun, Ying; Xu, Bo; Li, Xinpei; Wang, Xinghua; Zhang, Hanqi; Song, Daqian

    2015-08-12

    A novel method was developed for the determination of six triazine herbicides from oilseeds by matrix solid-phase dispersion combined with magnetic ionic liquid dispersive liquid-liquid microextraction (MSPD-MIL-DLLME), followed by ultrafast liquid chromatography with ultraviolet detection (UFLC-UV). The MIL, 1-butyl-3-methylimidazolium tetrachloroferrate ([C4mim][FeCl4]), was used as the microextraction solvent to simplify the extraction procedure by magnetic separation. The effects of several important experimental parameters, including type of dispersant, ratio of sample to dispersant, type and volume of collected elution solvent, type and volume of MIL, were investigated. Using the present method, UFLC-UV gave the limits of detection (LODs) of 1.20-2.72 ng g(-1) and the limits of quantification (LOQs) of 3.99-9.06 ng g(-1) for triazine herbicides. The recoveries were ranged from 82.9 to 113.7% and the relative standard deviations (RSDs) were equal or lower than 7.7%. The present method is easy-to-use and effective for extraction of triazine herbicides from oilseeds and shows the potentials of practical applications in the treatment of the fatty solid samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2010-08-01

    Full Text Available Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008. This model allows the reliable computation of the liquid-liquid coexistence curve (binodal, corresponding tie-lines, the limit of stability/metastability (spinodal, and further thermodynamic properties of multicomponent systems. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six

  13. Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

    Science.gov (United States)

    Zuend, A.; Marcolli, C.; Peter, T.; Seinfeld, J. H.

    2010-08-01

    Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008). This model allows the reliable computation of the liquid-liquid coexistence curve (binodal), corresponding tie-lines, the limit of stability/metastability (spinodal), and further thermodynamic properties of multicomponent systems. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH) and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility) are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six-component system

  14. A phase 2 trial of long-acting TransCon growth hormone in adult GH deficiency

    DEFF Research Database (Denmark)

    Höybye, Charlotte; Pfeiffer, Andreas F H; Ferone, Diego

    2017-01-01

    TransCon growth hormone is a sustained release human growth hormone prodrug in development in which unmodified growth hormone is transiently linked to a carrier molecule. It is intended as an alternative to daily growth hormone in the treatment of growth hormone deficiency. This was a multi-cente...

  15. Thermodynamic Study of the Role of Interface Curvature on Multicomponent Vapor-Liquid Phase Equilibrium.

    Science.gov (United States)

    Shardt, Nadia; Elliott, Janet A W

    2016-04-14

    The effect of interface curvature on phase equilibrium has been much more studied for single-component than multicomponent systems. We isolate the effect of curvature on multicomponent vapor-liquid equilibrium (VLE) phase envelopes and phase composition diagrams using the ideal system methanol/ethanol and the nonideal system ethanol/water as illustrative examples. An important finding is how nanoscale interface curvature shifts the azeotrope (equal volatility point) of nonideal systems. Understanding of the effect of curvature on VLE can be exploited in future nanoscale prediction and design.

  16. Calculation of Liquid Water-Hydrate-Methane Vapor Phase Equilibria from Molecular Simulations

    DEFF Research Database (Denmark)

    Jensen, Lars; Thomsen, Kaj; von Solms, Nicolas

    2010-01-01

    Monte Carlo simulation methods for determining fluid- and crystal-phase chemical potentials are used for the first time to calculate liquid water-methane hydrate-methane vapor phase equilibria from knowledge of atomistic interaction potentials alone. The water and methane molecules are modeled...... potential of the zero-occupancy hydrate system using thermodynamic integration from an Einstein crystal reference state, and (iii) thermodynamic integration to obtain the water and guest molecules' chemical potentials as a function of the hydrate occupancy. The three-phase equilibrium curve is calculated...... value at corresponding conditions. While computationally intensive, simulations such as these are essential to map the thermodynamically stable conditions for hydrate systems....

  17. Raman Spectroscopic Study of the Vapour Phase of 1-Methylimidazolium Ethanoate, a Protic Ionic Liquid

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Canongia Lopes, Jose N.; Ferreira, Rui

    2010-01-01

    The gas phase over the ionic liquid 1-methylimidazolium ethanoate, [Hmim][O2CCH3], was studied by means of Raman spectroscopy. Raman spectra are presented, the species in the gas phase are identified, and their bands are assigned. The results are interpreted using ab initio quantum mechanical cal...... calculations that also predict vibrational spectra. The obtained data reinforce a previous interpretation, based on FT-ICR mass spectrometric data, that the vapor phase over [Hmim][O2CCH3] consists predominantly of two neutral molecules, monomeric ethanoic acid and 1-methylimidazole....

  18. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, January-March 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-04-30

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the third quarter modifications to both the calorimeter and the phase equilibria system were completed. The phase equilibria system was checked out against literature data for methanol/ethanol. Results of these tests are included in this report. The calorimeter was evaluated using previously confirmed heptane data and published data by Thinh, et al. These results are also reported. Initial calorimetry data have been obtained for tetralin and the data will be reported when the data set has been completed. 5 refs., 5 figs., 3 tabs.

  19. Simulations of electrolytes at the liquid-liquid interface and of lanthanide cations complexes in gas phase; Simulations d'electrolytes a l'interface liquide/liquide et de complexes de cations lanthanides en phase gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Berny, F

    2000-07-01

    Two processes related to liquid/liquid extraction of ions by extractant molecules were studied: the ion approach at the interface and the ion complexation by ligands. In the first part, the behaviour of salts at the chloroform/water interface was simulated by molecular dynamics. The aim was to understand the way these salts ions approach the interface in order to be extracted. Some ions are repelled by the interface (K{sup +}, Cl{sup -}, UO{sub 2}{sup 2+}, Na{sup +}, NO{sub 3}{sup -}) whereas others adsorb (amphiphilic molecules and also ClO{sub 4}{sup -}, SCN{sup -}, guanidinium Gu{sup +} and picrate Pic{sup -}). The surface-active counter-ions make the ion approach at the interface easier. In a perfectly homogeneous mixture of the two solvents (water and chloroform) de-mixing, the ions seem to influence the phases separation rate. Nitric acid which is known to favour liquid/liquid extraction reveals strong adsorption at the interface in its neutral form and a smaller one in its ionic form (H{sub 3}O{sup +}/NO{sub 3}{sup -}). HNO{sub 3} and H{sub 3}O{sup +} display particular orientations at the interface: hydrogen atoms are pointing in the direction of the water slab. The nature of the organic phase can also influence the ion approach at the interface. For example, Gu{sup +} and Pic{sup -} adsorb much less at the supercritical CO{sub 2}/water interface than at the chloroform/water interface. In the second part, complexes of La{sup 3+}, Eu{sup 3+} and Yb{sup 3+} with ligands such as amide, urea, thio-amide, thiourea were studied by quantum mechanics. Our calculations show that cation-ligand interactions depend on the nature of substituents on ligands, on the presence of counter-ions or on the number of ligands in the complex. Sulfur compounds seem to less interact with cations than oxygen compounds. Ureas interact as much as amides and are potentially good ligands. (author)

  20. A flow pattern map for two-phase liquid-gas flow under reduced gravity conditions

    Science.gov (United States)

    Rezkallah, K. S.; Zhao, L.

    1995-08-01

    Two-phase gas-liquid flows have a wide range of applications in space including the flow of cryogenics in transport lines and heat-transfer fluids in a thermal control system. The behavior of these systems under reduced gravity must be understood in order to optimize the design and maintenance of such systems. Experimental studies on two-phase flow patterns and their transitions were conducted aboard the NASA KC-135 aircraft. A large set of flow pattern data for water-air and glycerin/water-air of different viscosities was reported. It was shown that two-phase flow under reduced gravity can be classified into four glow patterns: bubbly, slug, frothy slug-annular, and annular flows. Transitions between slug and frothy slug-annular, and frothy slug-annular and annular flows were predicted well using the liquid and gas Weber numbers as the mapping coordinates.

  1. Calculation of liquid-liquid phase separation in a ternary system of a polymer in a mixture of a solvent and a nonsolvent

    NARCIS (Netherlands)

    Altena, Frank W.; Smolders, C.A.

    1982-01-01

    A numerical method for the calculation of the binodal of liquid-liquid phase separation in a ternary system is described. The Flory-Huggins theory for three-component systems is used. Binodals are calculated for polymer/solvent/nonsolvent systems which are used in the preparation of asymmetric

  2. Comprehensive two-dimensional liquid chromatography: Ion chromatography × reversed-phase liquid chromatography for separation of low-molar-mass organic acids

    NARCIS (Netherlands)

    Brudin, S.S.; Shellie, R.A.; Haddad, P.R.; Schoenmakers, P.J.

    2010-01-01

    In the work presented here a novel approach to comprehensive two-dimensional liquid chromatography is evaluated. Ion chromatography is chosen for the first-dimension separation and reversed-phase liquid chromatography is chosen for the second-dimension separation mode. The coupling of these modes is

  3. Liquid crystal phase transitions in systems of colloidal platelets with bimodal shape distribution.

    Science.gov (United States)

    Verhoeff, A A; Wensink, H H; Vis, M; Jackson, G; Lekkerkerker, H N W

    2009-10-15

    We have studied a system of polydisperse, charged colloidal gibbsite platelets with a bimodal distribution in the particle aspect ratio. We observe a density inversion of the coexisting isotropic and nematic phases as well as a three-phase equilibrium involving a lower density nematic phase, an isotropic phase of intermediate density, and a higher density columnar phase. To relate these phenomena to the bimodality of the shape distribution, we have calculated the liquid crystal phase behavior of binary mixtures of thick and thin hard platelets for various thickness ratios. The predictions are based on the Onsager-Parsons theory for the isotropic-nematic (I-N) transition combined with a modified Lennard-Jones-Devonshire cell theory for the columnar (C) state. For sufficiently large thickness ratios, the phase diagram features an I-N density inversion and triphasic I-N-C equilibrium, in agreement with experiment. The density inversion can be attributed to a marked shape fractionation among the coexisting phases with the thick species accumulating in the isotropic phase. At high concentrations, the theory predicts a coexistence between two columnar phases with distinctly different concentrations. In experiment, however, the demixing transition is pre-empted by a transition to a kinetically arrested, glassy state with structural features resembling a columnar phase.

  4. Theoretical and Computational Studies of Condensed-Phase Phenomena: The Origin of Biological Homochirality, and the Liquid-Liquid Phase Transition in Network-Forming Fluids

    Science.gov (United States)

    Ricci, Francesco

    This dissertation describes theoretical and computational studies of the origin of biological homochirality, and the existence of a liquid-liquid phase transition in pure-component network-forming fluids. A common theme throughout these studies is the use of sophisticated computer simulation and statistical mechanics techniques to study complex condensed-phase phenomena. In the first part of this dissertation, we use an elementary lattice model with molecular degrees of freedom, and satisfying microscopic reversibility, to investigate the effect of reaction reversibility on the evolution of stochastic symmetry breaking via autocatalysis and mutual inhibition in a closed system. We identify conditions under which the system's evolution towards racemic equilibrium becomes extremely slow, allowing for long-time persistence of a symmetry-broken state. We also identify a "monomer purification" mechanism, due to which a nearly homochiral state can persist for long times, even in the presence of significant reverse reaction rates. Order of magnitude estimates show that with reasonable physical parameters a symmetry broken state could persist over geologically-relevant time scales. In the second part of this dissertation, we study a chiral-symmetry breaking mechanism known as Viedma ripening. We develop a Monte Carlo model to gain further insights into the mechanisms capable of reproducing key experimental signatures associated with this phenomenon. We also provide a comprehensive investigation of how the model parameters impact the system's overall behavior. It is shown that size-dependent crystal solubility alone is insufficient to reproduce most experimental signatures, and that some form of a solid-phase chiral feedback mechanism (e.g., agglomeration) must be invoked in our model. In the third part of this dissertation, we perform rigorous free energy calculations to investigate the possibility of a liquid-liquid phase transition (LLPT) in the Stillinger-Weber (SW

  5. Applications of Liquid-Phase Microextraction in the Sample Preparation of Environmental Solid Samples

    Directory of Open Access Journals (Sweden)

    Helena Prosen

    2014-05-01

    Full Text Available Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc. published in the last decade. Several innovative liquid-phase microextraction (LPME techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME, hollow fiber-liquid phase microextraction (HF-LPME, dispersive liquid-liquid microextraction (DLLME. Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact.

  6. Gas phase microreaction: nanomaterials synthesis via plasma exposure of liquid droplets

    Science.gov (United States)

    Maguire, Paul; Mahony, Charles; Kelsey, Colin; Hamilton, Neil; Askari, Sadegh; Macias-Montero, Manuel; Diver, Declan; Mariotti, Davide

    2015-09-01

    Plasma-liquid interactions are complex but offer considerable scope for use in nanomaterials synthesis. The introduction of individual picolitre micro-droplets into a steady-state low temperature plasma at atmospheric pressure, offers opportunities for enhanced scope and control of plasma-liquid chemistry and material properties. The gas-phase micro-reactor is similar in concept to liquid bubble microfluidics currently under intense research but with enhanced opportunities for scale-up. For nanomaterials and quantum dot synthesis, the addition of a liquid phase within the plasma expands considerably the scope for core-shell and alloy formation. The synthesis and encapsulation within a liquid droplet allows continuous delivery of nanoparticles to remote sites for plasma medicine, device fabrication or surface coating. We have synthesized Au nanoparticles in flight using AuHCl4 droplets with plasma flight times <0.1 ms. Also, Ag nanoparticles have been synthesized downstream via the delivery of plasma exposed water droplets onto AgNO3 laden substrates. Funding from EPSRC acknowledged (Grants EP/K006088/1 and EP/K006142/1).

  7. Separation of curcuminoids using ionic liquid based aqueous two-phase system coupled with in situ dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Shu, Yang; Gao, Mingcen; Wang, Xueying; Song, Rusheng; Lu, Jun; Chen, Xuwei

    2016-01-01

    An aqueous two-phase extraction system (ATPS) combined with an in situ dispersive liquid-liquid microextraction (DLLME) method using imidazolium ionic liquids (ILs) for the separation of curcuminoids is developed. The influence of structure of IL, the type of metathesis reagents, and the back extraction agents on the extraction efficiency is investigated. 2.0mg of curcuminoids are extracted by an IL ATPS composed of 0.4g 1,3-diethylimidazolium iodine (EeimI), 0.6g potassium hydrogen phosphate, 1.0g water. Then the bis[(trifluoromethyl)sulfonyl]imide lithium (LiNTf2) aqueous solution is added to the EeimI-rich phase of the ATPS. The water-immiscible ionic liquids, 1,3-diethylimidazole bis[(trifluoromethyl)sulfonyl]imide (EeimNTf2), forms by the metathesis reaction. The in situ DLLME is triggered simultaneously and further purifies the curcuminoids. 92% of EeimI transforms into EeimNTf2 and thus the Eeim(+) cation is used for twice in this method. Finally, 0.1mol/L NaOH aqueous solution is used as the back extraction reagent. The curcuminoids precipitate is achieved with 93% of recovery when the aqueous solution is adjusted to pH 3.0. This ATPS-DLLME method is successfully applied to the separation of curcuminoids from Curcuma Longa (0.96±0.02% of extraction yield, a purity of >51% with respect to the total dry mass of the product). Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Experimental and CFD Simulations of Vertical Two-Phase Slug Flow for Gas-Newtonian and Non-Newtonian Liquids

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Majumder, S.

    Gas-liquid two-phase flows are presented everywhere in industrial processes (i.e. gas-oil pipelines). In spite of the common occurrence of these two-phase flows, their understanding is limited compared to single-phase flows. Different studies on two-phase flow have focus on developing empirical c...

  9. Numerical simulation and analysis of solid-liquid two-phase flow in centrifugal pump

    Science.gov (United States)

    Zhang, Yuliang; Li, Yi; Cui, Baoling; Zhu, Zuchao; Dou, Huashu

    2013-01-01

    The flow with solid-liquid two-phase media inside centrifugal pumps is very complicated and the relevant method for the hydraulic design is still immature so far. There exist two main problems in the operation of the two-phase flow pumps, i.e., low overall efficiency and severe abrasion. In this study, the three-dimensional, steady, incompressible, and turbulent solid-liquid two-phase flows in a low-specific-speed centrifugal pump are numerically simulated and analyzed by using a computational fluid dynamics (CFD) code based on the mixture model of the two-phase flow and the RNG k- ɛ two-equation turbulence model, in which the influences of rotation and curvature are fully taken into account. The coupling between impeller and volute is implemented by means of the frozen rotor method. The simulation results predicted indicate that the solid phase properties in two-phase flow, especially the concentration, the particle diameter and the density, have strong effects on the hydraulic performance of the pump. Both the pump head and the efficiency are reduced with increasing particle diameter or concentration. However, the effect of particle density on the performance is relatively minor. An obvious jet-wake flow structure is presented near the volute tongue and becomes more remarkable with increasing solid phase concentration. The suction side of the blade is subject to much more severe abrasion than the pressure side. The obtained results preliminarily reveal the characteristics of solid-liquid two-phase flow in the centrifugal pump, and are helpful for improvement and empirical correction in the hydraulic design of centrifugal pumps.

  10. Quantifying the Self-Assembly Behavior of Anisotropic Nanoparticles Using Liquid-Phase Transmission Electron Microscopy.

    Science.gov (United States)

    Luo, Binbin; Smith, John W; Ou, Zihao; Chen, Qian

    2017-05-16

    For decades, one of the overarching objectives of self-assembly science has been to define the rules necessary to build functional, artificial materials with rich and adaptive phase behavior from the bottom-up. To this end, the computational and experimental efforts of chemists, physicists, materials scientists, and biologists alike have built a body of knowledge that spans both disciplines and length scales. Indeed, today control of self-assembly is extending even to supramolecular and molecular levels, where crystal engineering and design of porous materials are becoming exciting areas of exploration. Nevertheless, at least at the nanoscale, there are many stones yet to be turned. While recent breakthroughs in nanoparticle (NP) synthesis have amassed a vast library of nanoscale building blocks, NP-NP interactions in situ remain poorly quantified, in large part due to technical and theoretical impediments. While increasingly many applications for self-assembled architectures are being demonstrated, it remains difficult to predict-and therefore engineer-the pathways by which these structures form. Here, we describe how investigations using liquid-phase transmission electron microscopy (TEM) have begun to play a role in pursuing some of these long-standing questions of fundamental and far-reaching interest. Liquid-phase TEM is unique in its ability to resolve the motions and trajectories of single NPs in solution, making it a powerful tool for studying the dynamics of NP self-assembly. Since 2012, liquid-phase TEM has been used to investigate the self-assembly behavior of a variety of simple, metallic NPs. In this Account, however, we focus on our work with anisotropic NPs, which we show to have very different self-assembly behavior, and especially on how analysis methods we and others in the field are developing can be used to convert their motions and trajectories revealed by liquid-phase TEM into quantitative understanding of underlying interactions and dynamics

  11. Enhanced Densification of PM Steels by Liquid Phase Sintering with Boron-Containing Master Alloy

    Science.gov (United States)

    Vattur Sundaram, Maheswaran; Surreddi, Kumar Babu; Hryha, Eduard; Veiga, Angela; Berg, Sigurd; Castro, Fransisco; Nyborg, Lars

    2018-01-01

    Reaching high density in PM steels is important for high-performance applications. In this study, liquid phase sintering of PM steels by adding gas-atomized Ni-Mn-B master alloy was investigated for enhancing the density levels of Fe- and Mo- prealloyed steel powder compacts. The results indicated that liquid formation occurs in two stages, beginning with the master alloy melting (LP-1) below and eutectic phase formation (LP-2) above 1373 K (1100 °C). Mo and C addition revealed a significant influence on the LP-2 temperatures and hence on the final densification behavior and mechanical properties. Microstructural embrittlement occurs with the formation of continuous boride networks along the grain boundaries, and its severity increases with carbon addition, especially for 2.5 wt pct of master alloy content. Sintering behavior, along with liquid generation, microstructural characteristics, and mechanical testing revealed that the reduced master alloy content from 2.5 to 1.5 wt pct (reaching overall boron content from 0.2 to 0.12 wt pct) was necessary for obtaining good ductility with better mechanical properties. Sintering with Ni-Mn-B master alloy enables the sintering activation by liquid phase formation in two stages to attain high density in PM steels suitable for high-performance applications.

  12. A novel liquid-phase strategy for organic synthesis using organic ions as soluble supports.

    Science.gov (United States)

    Huo, Congde; Chan, Tak Hang

    2010-08-01

    This critical review describes a new liquid-phase strategy for organic synthesis by using organic ions as soluble supports. Catalysts or reagents or substrates are immobilized onto organic ions. They are generally soluble in polar organic solvents (e.g. CH(3)CN) or ionic liquids but insoluble in non-polar solvents (e.g. ether or hexanes). Their reactions are carried out in homogeneous solution phase with a polar organic solvent or ionic liquid. After the reaction, the ion-supported species can be phase separated through precipitation from the polar organic solvent by the addition of a less polar organic solvent or extraction with organic solvents from ionic liquids. The ion-supported species can therefore be easily recovered and purified from the reaction mixture by simple washings with the less polar solvent. The ion-tagged species can function in the role of a catalyst, or as a reagent, or as the substrate in the synthesis of small molecules or bio-oligomers. Ion-supported catalysts and reagents can usually be recovered and reused with little diminution of activity. Important biooligomers such as peptides, oligosaccharides and oligonucleotides have been synthesized with this method (136 references).

  13. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, October-December 1984

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-01-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the second quarter efforts were limited to ordering and installing equipment to improve the operability of the calorimeter and phase behavior system. The program is now up to full staffing levels and data collection will begin this next quarter. The objectives of this program are to study the enthalpy and phase behavior of a selected ternary model compound system, representative of interactions present in coal derived liquids. Measurements will be made in a Freon 11 reference fluid boil off calorimeter, and an equilibrium flash vaporization apparatus. These experimental systems have already been developed. Previous studies have indicated that existing data and correlations developed for petroleum fluids are not applicable to coal derived liquids. This is due to the presence of significant concentrations of polar associating heteroatomics in the predominantly aromatic coal liquids. Thus, the ternary system will include an aromatic, a basic nitrogen compound, and a cresol. It is presently planned to study the tetralin/quinoline/m-cresol ternary mixture. Measurements will be made over a wide range of temperature (200 to 700/sup 0/C) and pressure (20 to 1500 psia), for the three pure compounds.

  14. Liquid Phase Methanol LaPorte PDU: Modification, operation, and support studies

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.M. (Air Products and Chemicals, Inc., Allentown, PA (United States)); Frank, M.E. (Chem Systems, Inc., Tarrytown, NY (United States))

    1988-08-10

    To strengthen the data base of the Liquid Phase Methanol LaPorte technology, research is being conducted in parallel with the process development unit engineering and construction efforts. This work will address alternate liquid media studies, effects of CO{sub 2} in CO-rich synthesis gas, optimization of in-situ catalyst reduction and storage, catalyst poison studies, fundamental kinetic modelling, testing alternate commercial catalysts, and field testing of new guard-bed materials for catalyst poisons. Tests will be performed primarily using CO-rich synthesis gas. (VC)

  15. Nearly-analogue blazed phase grating using high birefringence liquid crystal

    Science.gov (United States)

    Bennis, N.; Geday, M. A.; Quintana, X.; Cerrolaza, B.; Medialdea, D. P.; Spadło, A.; Dąbrowski, R.; Otón, J. M.

    2009-06-01

    Diffraction of liquid crystal gratings has been thoroughly studied for many applications such as diffraction optics, optical processing, and spectral analysis. In pure optical processing one varies the direction of propagation of light beam without any mechanical adjustment. In this work we propose a beam steering device using highly birefringent liquid crystal material. Using a highly birefringent material one can reduce the LC layer thickness needed to achieve 2π of phase modulation and thus reduce the fringing effect caused by deformation of the electric field at the edge of the pixel. Here, we present 1.5-µm thick, high-resolution diffraction grating with non-detectable fringing.

  16. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, January-March 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1986-04-30

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the seventh quarter, preliminary enthalpy measurements for the 5/6:1/6 m-cresol/tetralin binary mixture have been completed and are included in Appendix A at the end of this report. Vapor liquid equilibria VLE measurements for the m-cresol/tetralin system have been completed for four isotherms; 250, 275, 300, 325/sup 0/C. These results and a summary of progress to date for the VLE apparatus are in the appendix at the end of this report. 10 refs., 15 figs., 6 tabs.

  17. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, July-September 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-10-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the fifth quarter, preliminary enthalpy measurements for the 50/50 mole percent m-cresol/tetralin binary mixture have almost been completed and figure illustrating the preliminary results have been included in this report. Vapor liquid equilibria measurements for the m-cresol/quinoline system have been completed for four isotherms. Results have been included in this report. 6 refs., 13 figs., 4 tabs.

  18. Liquid-phase microextraction for simultaneous chromatographic analysis of three antidepressant drugs in plasma

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Dobrovolskni Porto

    2012-01-01

    Full Text Available A method using Liquid Phase Microextraction for simultaneous detection of citalopram (CIT, paroxetine (PAR and fluoxetine (FLU, using venlafaxine as internal standard, in plasma by high performance liquid chromatography with fluorescence detection was developed. The linearity was evaluated between 5.0 and 500 ng mL-1 (r > 0.99 and the limit of quantification was 2.0, 3.0 and 5.0 ng mL-1 for CIT, PAR and FLU, respectively. Therefore, it can be applied to therapeutic drug monitoring, pharmacokinetics or bioavailability studies and its advantages are that it necessary relatively inexpensive equipment and sample preparation techniques.

  19. Preparation and evaluation of pillararene bonded silica gel stationary phases for high performance liquid chromatography.

    Science.gov (United States)

    Zhao, Wenjie; Chu, Jianxiang; Xie, Fuwei; Duan, Qunpeng; He, Lijun; Zhang, Shusheng

    2017-02-17

    Pillararene bonded stationary phases for high performance liquid chromatography were prepared using 3-aminopropyltriethoxysilane as coupling reagent. The structure of the new materials was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic performance and retention mechanism of the new stationary phases were evaluated in reversed-phase mode compared with C18 using different solute probes including Tanaka test solutes, polycyclic aromatic hydrocarbons, phenols and aromatic positional isomers. The new stationary phases could provide various interactions for different solutes, such as hydrophobic, hydrogen bonding, π-π and inclusion interactions. The synergistic effects resulting from aromatic rings, oxygen atoms, alkyl linkers and cavities in the new host molecules improved the separation selectivity by multiple retention mechanisms. Such hybrid stationary phases can provide more versatility and have great potential for the analysis of complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Simultaneous analysis of fourteen endogenous steroid hormones by liquid chromatography tandem mass spectrometry with atmospheric pressure photoionization

    Science.gov (United States)

    Product Description: To understand how some chemicals affect the endocrine system, controlled lab experiments often monitor how chemicals impact natural steroid hormones in fish. Current methods can target only one or two hormones in a single sample, limiting the information that...

  1. Characterization of surface confined ionic liquid stationary phases: impact of cation revisited.

    Science.gov (United States)

    VanMiddlesworth, Bradley J; Stalcup, Apryll M

    2014-10-17

    Modification of the Linear Solvation Energy Relationship (LSER) equation to account for ionic interactions in the retention of ionizable compounds has enabled the elucidation in the effect of the imidazolium cation identity on retention. Three Surface Confined Ionic Liquid stationary phases were synthesized from an octylbromide phase on silica: 1-octyl-3-methylimidazolium bromide (MIM), 1-octyl-3-butylimidazolium bromide (BIM), and 1-octyl-3-benzylimidazolium bromide (BzIM). These phases were probed via a 35 analyte probe set, including 6 phenolic acids, 5 anilinic bases, and 2 pyridinic bases, and the resulting column parameters compared with previously reported interactions of ionic liquids or Surface Confined Ionic Liquids. The correlation between experimental and calculated retention for the conventional, 6-parameter LSER equation was very poor: r(2)=0.64 (MIM), 0.60 (BIM), and 0.62 (BzIM). By accounting for the ionic interactions between stationary phase and analytes, linearity for the modified, 8 parameter LSER equation was significantly improved to r(2)=0.997 (MIM), 0.996 (BIM), and 0.997 (BzIM). The primary difference between cation identities is within the retention of acids where BIM>BzIM>MIM. We conjecture that the accessibility of bulky, acidic analytes to the on-top interaction of the imidazolium ring is the major contributor to increased anion retention. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Stability analysis of inclined stratified two-phase gas-liquid flow

    Energy Technology Data Exchange (ETDEWEB)

    Salhi, Yacine, E-mail: yasalhi@ulb.ac.b [Laboratoire de Mecanique des Fluides Theorique et Appliquee, Faculte de Physique, U.S.T.H.B. El-Alia B.P. 32 16111. Alger (Algeria); Service Aero-Thermo-Mecanique Faculte des Sciences Appliquees Universite Libre de Bruxelles CP165, avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgique (Belgium); Si-Ahmed, El-Khider [Laboratoire de Mecanique des Fluides Theorique et Appliquee, Faculte de Physique, U.S.T.H.B. El-Alia B.P. 32 16111. Alger (Algeria); GEPEA, Universite de Nantes, CNRS, UMR6144, CRTT-BP 406, 44602 Saint-Nazaire (France); Legrand, Jack [GEPEA, Universite de Nantes, CNRS, UMR6144, CRTT-BP 406, 44602 Saint-Nazaire (France); Degrez, Gerard [Service Aero-Thermo-Mecanique Faculte des Sciences Appliquees Universite Libre de Bruxelles CP165, avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgique (Belgium)

    2010-05-15

    The present investigation involves the modeling of gas-liquid interface in a two-phase stratified flow through a horizontal or nearly-horizontal circular duct. The most complete and fundamental model used for these calculations is known as the one-dimensional two-fluid model. It is the most accurate of the two-phase models since it considers each phase independently and links both phases with six conservation equations. The mass and momentum balance equations are written in dimensionless form. The dimensionless mass and momentum balance equations are combined with the method of characteristics and an explicit method to simulate the flow. At first, the linear stability of the flow is investigated by disturbing the liquid flow with a small perturbation. An improved version of the one-dimensional two-fluid model for horizontal flows is developed as a set of non-linear hyperbolic governing equations. The importance of this research lies in obtaining a model that accounts for the effects of flow and geometrical conditions (such as liquid viscosity, surface tension). It is shown that, for positive values of the slope angle (upward inclination), the slug flow becomes more probable, whereas negative values of the slope angle (downward inclination) induce a more stable stratified flow.

  3. Modelling and numerical simulation of liquid-vapor phase transitions; Modelisation et simulation numerique des transitions de phase liquide-vapeur

    Energy Technology Data Exchange (ETDEWEB)

    Caro, F

    2004-11-15

    This work deals with the modelling and numerical simulation of liquid-vapor phase transition phenomena. The study is divided into two part: first we investigate phase transition phenomena with a Van Der Waals equation of state (non monotonic equation of state), then we adopt an alternative approach with two equations of state. In the first part, we study the classical viscous criteria for selecting weak solutions of the system used when the equation of state is non monotonic. Those criteria do not select physical solutions and therefore we focus a more recent criterion: the visco-capillary criterion. We use this criterion to exactly solve the Riemann problem (which imposes solving an algebraic scalar non linear equation). Unfortunately, this step is quite costly in term of CPU which prevent from using this method as a ground for building Godunov solvers. That is why we propose an alternative approach two equations of state. Using the least action principle, we propose a phase changing two-phase flow model which is based on the second thermodynamic principle. We shall then describe two equilibrium submodels issued from the relaxations processes when instantaneous equilibrium is assumed. Despite the weak hyperbolicity of the last sub-model, we propose stable numerical schemes based on a two-step strategy involving a convective step followed by a relaxation step. We show the ability of the system to simulate vapor bubbles nucleation. (author)

  4. Investigations on the liquid crystalline phases of cation-induced condensed DNA

    Science.gov (United States)

    Pillai, C. K. S.; Sundaresan, Neethu; Radhakrishnan Pillai, M.; Thomas, T.; Thomas, T. J.

    2005-10-01

    Viral and nonviral condensing agents are used in gene therapy to compact oligonucleotides and plasmid DNA into nanostructures for their efficient transport through the cell membranes. Whereas viral vectors are best by the toxic effects on the immune system, most of the nonviral delivery vehicles are not effective for use in clinical system. Recent investigations indicate that the supramolecular organization of DNA in the condensed state is liquid crystalline. The present level of understanding of the liquid crystalline phase of DNA is inadequate and a thorough investigation is required to understand the nature, stability, texture and the influence of various environmental conditions on the structure of the phase. The present study is mainly concerned with the physico-chemical investigations on the liquid crystalline transitions during compaction of DNA by cationic species such as polyamines and metallic cations. As a preliminary to the above investigation, studies were conducted on the evolution of mesophase transitions of DNA with various cationic counterion species using polarized light microscopy. These studies indicated significant variations in the phase behaviour of DNA in the presence of Li and other ions. Apart from the neutralization of the charges on the DNA molecule, these ions are found to influence selectively the hydration sphere of DNA that in turn influences the induction and stabilization of the LC phases. The higher stability observed with the liquid crystalline phases of Li--DNA system could be useful in the production of nanostructured DNA. In the case of the polyamine, a structural specificity effect depending on the nature, charge and structure of the polyamine used has been found to be favoured in the crystallization of DNA.

  5. Photoluminescence quenching of porous silicon in gas and liquid phases - the role of dielectric quenching and capillary condensation effects

    Energy Technology Data Exchange (ETDEWEB)

    Dian, Juraj [Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University Prague, Ke Karlovu 3, 121 16 Prague 2 (Czech Republic); Chvojka, Tomas; Vrkoslav, Vladimir; Jelinek, Ivan [Department of Analytical Chemistry, Faculty of Sciences, Charles University Prague, Hlavova 2030, 128 40 Prague 2 (Czech Republic)

    2005-06-01

    We present a systematic study of porous silicon photoluminescence quenching in the presence of precisely controlled amounts of linear aliphatic alcohols (from methanol to hexanol) in gas and liquid phases. From the concentration dependence of photoluminescence quenching response we determined sensitivity of porous silicon sensor for studied analytes. The sensor sensitivity revealed nearly monotonous change with the length of alcohol molecule within the homological set of alcohols in both gas and liquid phases. However, while in gas phase the sensor sensitivity rose with the length of alcohol chain, in liquid phase we observed the opposite behaviour. Photoluminescence quenching behaviour in liquid phase is very well explained by exciton dielectric quenching mechanism. In gas phase photoluminescence quenching depends both on analyte dielectric constant and analyte equilibrium concentration inside porous matrix which is controlled by capillary condensation effect. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Gas-liquid two-phase flows in an upward square pipe with sudden expansion

    Science.gov (United States)

    Kim, Yewon; Park, Hyungmin

    2017-11-01

    The bubble dynamics and consequent changes in the liquid-phase flow characteristics in an upward bubbly square pipe with sudden expansion (expansion ratio of 2.0) are experimentally studied in this work. The experiments are conducted under two Reynolds numbers of 600 (laminar) and 6600 (turbulent), respectively, based on the inlet bulk velocities of the single-phase (without bubbles) flow. The mean volume void fraction and averaged bubble size considered are 1% and 3.5 mm, respectively, and we use the high-speed two-phase particle image velocimetry and the shadowgraphy to measure the gas and liquid phases simultaneously. In addition, the particle tracking velocimetry is performed using two cameras to track the three-dimensional paths of each bubble. It is observed that lateral void fraction distribution change to core peak from wall peak after sudden expansion and peak at near the wall again after 3 times of inlet pipe width. Also, the reattachment length in the two-phase flow decreases compared to that of a single-phase flow, while smaller bubbles tend to migrate into the recirculation region and being trapped. Further discussions on the turbulence statistics and Reynolds number effects will be given. Supported by NRF Grant (NRF-2016R1C1B2012775) of the Korean Government.

  7. [Screening and confirmation of 24 hormones in cosmetics by ultra high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry].

    Science.gov (United States)

    Li, Zhaoyong; Wang, Fengmei; Niu, Zengyuan; Luo, Xin; Zhang, Gang; Chen, Junhui

    2014-05-01

    A method of ultra high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (UPLC-LTQ/Orbitrap MS) was established to screen and confirm 24 hormones in cosmetics. Various cosmetic samples were extracted with methanol. The extract was loaded onto a Waters ACQUITY UPLC BEH C18 column (50 mm x 2.1 mm, 1.7 microm) using a gradient elution of acetonitrile/water containing 0.1% (v/v) formic acid for the separation. The accurate mass of quasi-molecular ion was acquired by full scanning of electrostatic field orbitrap. The rapid screening was carried out by the accurate mass of quasi-molecular ion. The confirmation analysis for targeted compounds was performed with the retention time and qualitative fragments obtained by data dependent scan mode. Under the optimal conditions, the 24 hormones were routinely detected with mass accuracy error below 3 x 10(-6) (3 ppm), and good linearities were obtained in their respective linear ranges with correlation coefficients higher than 0.99. The LODs (S/N = 3) of the 24 compounds were hormones in 50 cosmetic samples. The results demonstrate that the method is a useful tool for the rapid screening and identification of the hormones in cosmetics.

  8. Three-phase, liquid-phase microextraction combined with high performance liquid chromatography-fluorescence detection for the simultaneous determination of fluoxetine and norfluoxetine in human plasma.

    Science.gov (United States)

    de Freitas, Daniela Fernanda; Porto, Carlos Eduardo Dobrovolskin; Vieira, Elisabeth Pizzamiglio; de Siqueira, Maria Elisa Pereira Bastos

    2010-01-05

    A three-phase, liquid-phase microextraction using a hollow fibre (HF-LPME) combined with high performance liquid chromatography-fluorescence detection (HPLC-FL) was developed for the analysis of fluoxetine (FLX) and its active metabolite, norfluoxetine (NFLX), in human plasma. An HF-LPME system using a disposable 7-cm polypropylene porous hollow fibre, 5 mL of alkaline plasma solution (donor phase), n-hexyl ether (extraction solvent) and 20 mM hydrochloric acid (acceptor phase) was used in the extraction. The method was validated after optimisation of several parameters that influence LPME efficiency. A reverse-phase LiChrospher 60 RP-Select B column (125 mm x 4 mm, 5 microm particle size) was used with 0.005 M sodium acetate buffer (pH 4.5) and acetonitrile at a 50:50 (v/v) as the mobile phase at a flow rate of 0.6 mL min(-1). In these conditions satisfactory chromatographic resolution and efficiency for the analytes were obtained. Fluorescence detection at 230 nm excitation wavelength and 290 nm emission wavelength was performed. Linearity over a range of 5-500 ng mL(-1), with determination coefficients (R(2)) of 0.9999 and 0.9962 for FLX and NFLX, respectively, was established. Venlafaxine was used as the internal standard for both analytes. Extraction recoveries from plasma samples were 70.9% for FLX and 59.7% for NFLX. The intra-day coefficients of variation (CVs) were below 5.4%, and inter-day CVs were below 13.0%, for both analytes at concentrations of 20, 80 and 160 ng mL(-1). HF-LPME extraction followed by HPLC-FL detection for FLX and NFLX analyses demonstrated excellent sample clean-up and selectivity. This method was simple, cheap, and easy to perform, yielding substantial analytes enrichment. The method was applied to the analysis of samples from 12 patients under fluoxetine treatment and proved suitable for routine therapeutic drug monitoring for this antidepressant.

  9. Phase diagram and universality of the Lennard-Jones gas-liquid system

    KAUST Repository

    Watanabe, Hiroshi

    2012-01-01

    The gas-liquid phase transition of the three-dimensional Lennard-Jones particles system is studied by molecular dynamics simulations. The gas and liquid densities in the coexisting state are determined with high accuracy. The critical point is determined by the block density analysis of the Binder parameter with the aid of the law of rectilinear diameter. From the critical behavior of the gas-liquid coexisting density, the critical exponent of the order parameter is estimated to be β = 0.3285(7). Surface tension is estimated from interface broadening behavior due to capillary waves. From the critical behavior of the surface tension, the critical exponent of the correlation length is estimated to be ν = 0.63(4). The obtained values of β and ν are consistent with those of the Ising universality class. © 2012 American Institute of Physics.

  10. An overview of liquid phase microextraction approaches combined with UV-Vis spectrophotometry.

    Science.gov (United States)

    Dehghani Mohammad Abadi, Malihe; Ashraf, Narges; Chamsaz, Mahmoud; Shemirani, Farzaneh

    2012-09-15

    Ultraviolet and visible spectrophotometer has become a popular analytical instrument in the modern day laboratories. However, the low concentrations of many analytes in samples make it difficult to directly measure them by UV-Vis spectrophotometry. This overview focuses on the combinations of microvolume UV-Vis spectrophotometry with miniaturized approaches to sample preparation, namely, single drop microextraction (SDME), dispersive liquid-liquid microextraction (DLLME), cold induced aggregation microextraction (CIAME), in situ solvent formation microextraction (ISSFME), ultrasound assisted emulsification microextraction (USAEME), solidified floating organic drop microextraction (SFODME), and hollow fiber based liquid phase microextraction (HF-LPME) to improve both the selectivity and sensitivity. Integration of these techniques provides unique advantages which include availability, simplicity of operation, low cost, speed, precision and accuracy; hence making them a powerful tool in chemical analysis. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Phase transformations in liquids and the liquid–gas transition in fluids at supercritical pressures

    Science.gov (United States)

    Brazhkin, V. V.

    2017-12-01

    It is an experimental fact that in the neighborhood of melting curves, including those measured at above-critical pressures and temperatures, all fluids have some short- and intermediate-range order and their excitation spectra contain high-frequency transverse waves. At high pressure, both smooth and sharp first-order phase transitions involving changes in the liquid structure and properties can occur between various liquid states. However, at sufficiently high temperatures, any liquid loses its identity and turns into an unstructured dense gas in which only longitudinal waves can propagate. We discuss theoretical and experimental evidence for the existence of a boundary between a ‘solid-like’ melt and a dense gas at supercritical pressures.

  12. Numerical Simulations of Liquid-Gas-Solid Three-Phase Flows in Microgravity

    Directory of Open Access Journals (Sweden)

    Xinyu Zhang

    2012-03-01

    Full Text Available Three-phase liquid-gas-solid flows under microgravity condition are studied. An Eulerian-Lagrangian computational model was developed and used in the simulations. In this approach, the liquid flow was modeled by a volume-averaged system of governing equations, whereas motions of particles and bubbles were evaluated using the Lagrangian trajectory analysis procedure. It was assumed that the bubbles remained spherical, and their shape variations were neglected. The bubble-liquid, particle-liquid and bubbl-particle two-way interactions were accounted for in the analysis. The discrete phase equations used included drag, lift, buoyancy, and virtual mass forces. Particle-particle interactions and bubble-bubble interactions were accounted for by the hard sphere model. Bubble coalescence was also included in the model. The transient flow characteristics of the three-phase flow were studied; and the effects of gravity, inlet bubble size and g-jitter acceleration on variation of flow characteristics were discussed. The low gravity simulations showed that most bubbles are aggregated in the inlet region. Also, under microgravity condition, bubble transient time is much longer than that in normal gravity. As a result, the Sauter mean bubble diameter, which is proportional to the transient time of the bubble, becomes rather large, reaching to more than 9 mm. The bubble plume in microgravity exhibits a plug type flow behavior. After the bubble plume reaches the free surface, particle volume fraction increases along the height of the column. The particles are mainly located outside the bubble plume, with very few particles being retained in the plume. In contrast to the normal gravity condition, the three phases in the column are poorly mixed under microgravity conditions. The velocities of the three phases were also found to be of the same order. Bubble size significantly affects the characteristics of the three-phase flows under microgravity conditions. For

  13. Effect of first dimension phase selectivity in online comprehensive two dimensional liquid chromatography (LC × LC)

    Science.gov (United States)

    Gu, Haiwei; Huang, Yuan; Filgueira, Marcelo; Carr, Peter W.

    2012-01-01

    In this study, we examined the effect of first dimension column selectivity in reversed phase (RP) online comprehensive two dimensional liquid chromatography (LC × LC). The second dimension was always a carbon clad metal oxide reversed phase material. The hydrophobic subtraction model (HSM) and the related phase selective triangles were used to guide the selection of six different RP first dimension columns. Various kinds of samples were investigated and thus two different elution conditions were needed to cause full elution from the first dimension columns. We compared LC × LC chromatograms, contours plots, and fcoverage plots by measuring peak capacities, peak numbers, relative spatial coverage, correlation values, etc. The major finding of this study is that the carbon phase due to its rather different selectivity from other reversed phases is reasonably orthogonal to a variety of common types of bonded reversed phases. Thus quite surprisingly the six different first dimension stationary phases all showed generally similar separation patterns when paired to the second dimension carbon phase. This result greatly simplifies the task of choosing the correct pair of phases for RP × RP. PMID:21840009

  14. Impact of reversed phase column pairs in comprehensive two-dimensional liquid chromatography.

    Science.gov (United States)

    Allen, Robert C; Barnes, Brian B; Haidar Ahmad, Imad A; Filgueira, Marcelo R; Carr, Peter W

    2014-09-26

    A major issue in optimizing the resolving power of two-dimensional chromatographic separations is the choice of the two phases so as to maximize the distribution of the analytes over the separation space. In this work, we studied the choice of appropriate reversed phases to use in on-line comprehensive two-dimensional liquid chromatography (LC×LC). A set of four chemically different conventional bonded reversed phases was used in the first dimension. The second dimension column was either a conventional bonded C18 phase or a carbon-clad phase (CCP). The LC×LC chromatograms and contour plots were all rather similar indicating that the selectivities of the two phases were also similar regardless of the reverse phase column used in the first dimension. Further, the spatial coverage seen with all four first dimension stationary phases when paired with a second dimension C18 phase were low and the retention times were strongly correlated. However, when the C18 column was replaced with the CCP column much improved separations were observed with higher spatial coverages, greater orthogonalities and significant increases in the number of observed peaks. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Effect of first dimension phase selectivity in online comprehensive two dimensional liquid chromatography (LC×LC).

    Science.gov (United States)

    Gu, Haiwei; Huang, Yuan; Filgueira, Marcelo; Carr, Peter W

    2011-09-23

    In this study, we examined the effect of first dimension column selectivity in reversed phase (RP) online comprehensive two dimensional liquid chromatography (LC×LC). The second dimension was always a carbon clad metal oxide reversed phase material. The hydrophobic subtraction model (HSM) and the related phase selective triangles were used to guide the selection of six different RP first dimension columns. Various kinds of samples were investigated and thus two different elution conditions were needed to cause full elution from the first dimension columns. We compared LC×LC chromatograms, contours plots, and fcoverage plots by measuring peak capacities, peak numbers, relative spatial coverage, correlation values, etc. The major finding of this study is that the carbon phase due to its rather different selectivity from other reversed phases is reasonably orthogonal to a variety of common types of bonded reversed phases. Thus quite surprisingly the six different first dimension stationary phases all showed generally similar separation patterns when paired to the second dimension carbon phase. This result greatly simplifies the task of choosing the correct pair of phases for RP×RP. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Aniline-modified porous graphitic carbon for hydrophilic interaction and attenuated reverse phase liquid chromatography.

    Science.gov (United States)

    Iverson, Chad D; Lucy, Charles A

    2014-12-19

    Most stationary phases for hydrophilic interaction liquid chromatography (HILIC) and reversed phase liquid chromatography (RPLC) are based on silica. Porous graphitic carbon (PGC) is an attractive alternative to silica-based phases due to its chemical and thermal stability, and unique selectivity. However, native PGC is strongly hydrophobic and in some instances excessively retentive. PGC particles with covalently attached aniline groups (Dimethylaniline-PGC and Aniline-PGC) were synthesized to alter the surface polarity of PGC. First, the diazonium salt of N,N-dimethyl-p-phenylenediamine or 4-nitroaniline was adsorbed onto the PGC surface. The adsorbed salt was reduced with sodium borohydride and (Aniline-PGC only) the nitro group was further reduced with iron powder to the aniline. X-ray photoelectron spectroscopy confirmed the surface functionalities and that these moieties were introduced to the surface at concentrations of 0.9 and 2.1molecules/nm(2), respectively. These modified PGC phases (especially Aniline-PGC) were evaluated as HILIC and reversed phases. The Dimethylaniline-PGC phase displayed only weak HILIC retention of phenolic solutes. In contrast, the Aniline-PGC phase displayed up to nearly a 7-fold increase in HILIC retention vs. an aniline-silica phase and selectivity that differed from 10 other HILIC phases. Introduction of aniline groups to the PGC surface reduced the RPLC retentivity of PGC up to more than 5-fold and improved the separation efficiency up to 6-fold. The chromatographic performance of Aniline-PGC is demonstrated by separations of nucleotides, nucleosides, carboxylic acids, basic pharmaceuticals, and other compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. High resolution of racemic phenylalanine with dication imidazolium-based chiral ionic liquids in a solid-liquid two-phase system.

    Science.gov (United States)

    Huang, Xiaoxia; Wu, Haoran; Wang, Zhixia; Luo, Yingjie; Song, Hang

    2017-01-06

    A novel solid-liquid two-phase system was developed for the chiral separation of racemic phenylalanine with new dication imidazolium-based chiral ionic liquids. Preliminary experiments showed distinct enantioselectivity in amino acid extraction with the novel solid-liquid two-phase system, more L-enantiomer of amino acid cooperatively interacted with ionic liquids and copper ions to be the solid phase. Various factors, including the alkyl chain length of cations of ionic liquids, the amount of copper acetate, the ratio of n(ILs)/n(Cu2+), the amount of water and racemic phenylalanine, the resolution time together with the resolution temperature, were systematically investigated for their influence on resolution efficiency. The results showed that, under a certain condition, the enantiomeric excess value and the yield of phenylalanine in liquid phase (mainly containing D-enantiomer) were 67.8% and 96.5%, the enantiomeric excess value and the yield of phenylalanine in solid phase (mainly containing L-enantiomer) were 99.2% and 85.2%. Finally, 2D NMR technology, infrared spectroscopy and molecular simulation method were used to study the interaction mechanism. The results indicated that L-enantiomer of phenylalanine interacts more strongly with chiral ILs and Cu2+. The novel system has characteristics of free-organic solvent, simple operation, fast separation process and very high resolution efficiency for racemic phenylalanine. This work could provide a new and alternative resolution approach for other chiral separations. Copyright © 2016. Published by Elsevier B.V.

  18. Automatic regulation of liquid- and vapor-phase chambers in hydrogenation at the Leuna Plant

    Energy Technology Data Exchange (ETDEWEB)

    1944-01-23

    A chronological survey is given of the development and implementation of automatic regulation at Leuna. The first such apparatus introduced was a regulator for liquid level in a vessel used for allowing gases to escape from the sludge coming from the product separator of liquid-phase hydrogenation of brown coal. Next was developed a compressed-air-operated regulator for liquid level in the product separator itself. Next came a time-and-temperature regulated automatic valve for removing sand from oven I of the liquid-phase chambers. In order to measure and regulate the flow of liquid product under high pressure, there was developed a meter combining electric-pneumatic and photoelectric elements together with a specially-developed membrane-regulated valve structure, which seemed to be a great improvement in accuracy and dependability over previous valve structures. The electric-pneumatic valve apparatus mentioned above was also used in regulating reaction-oven temperature by regulating the rate of injection of cold gas into the oven to reduce the temperature built up by the exothermic reaction; temperature measurement was done by resistance thermometers. Another use for the electric-pneumatic valve apparatus was in the regulation of liquid level in intermediate seprator vessels; an improved design for cartridge valves was involved in such regulators. The arrangement of certain similar components of these regulators in a central location together with simple compressed-air connections to other operating components of the separate regulators is described. The compressed-air system using several different pressures used to operatethe regulators, is also considered. 10 diagrams, 1 table.

  19. Liquid phase micro-extraction: Towards the green methodology for ultratrace metals determination in aquatic ecosystems

    Directory of Open Access Journals (Sweden)

    López-López J. A.

    2013-04-01

    Full Text Available Heavy metals are normally found, in natural waters, in very low concentrations. Some of them are essential for life in low level; however, in higher level they are toxic. Therefore, analyzing their bio-available fraction is of main interest. Standard methodology is based in the collection of a number of samples from a water body. Collected samples must be stored, pre-treated and then analyzed. Pre-treatment usually involves pre-concentrating the metal, with the corresponding risk of contamination or loss of analyte. This way, punctual information is obtained from every sampling campaign. As an alternative, passive sampling techniques allow the continuous and coupled sampling-pre-treatment for heavy metals analysis, giving a better approach in the characterization of the studied water body. Liquid phase micro-extraction (LPME is a green analytical alternative for liquid-liquid extraction that promotes a reduction of sample volume, solvent needed and waste generation. Using these systems, polypropylene hollow fibers (HF with pores in their walls can be used. A few micro-liters of organic solvent are supported in the pores. The sample is placed in the outer part of the fiber and a receiving phase is placed in its inner part, allowing continuous liquid extraction of the metal from the sample. Several fibers with different physical features have been employed to analyzed total concentration and bio-availability of some heavy metals (Ag, Ni, Cu in natural water samples. Thanks to fibers configuration, devices for passive sampling based in HF-LPME could be designed. Advantages of this methodology over existing ones are supported because the receiving phase is liquid. As a consequence, retained metals do not need to be eluted from the acceptor prior to instrumental analysis.

  20. Gas-liquid two-phase flows in rectangular polymer micro-channels

    Science.gov (United States)

    Kim, Namwon; Evans, Estelle T.; Park, Daniel S.; Soper, Steven A.; Murphy, Michael C.; Nikitopoulos, Dimitris E.

    2011-08-01

    This study addresses gas-liquid two-phase flows in polymer (PMMA) micro-channels with non-molecularly smooth and poorly wetting walls (typical contact angle of 65°) unlike previous studies conducted on highly wetting molecularly smooth materials (e.g., glass/silicon). Four fundamentally different topological flow regimes (Capillary Bubbly, Segmented, Annular, Dry) were identified along with two transitory ones (Segmented/Annular, Annular/Dry) and regime boundaries were identified from the two different test chips. The regime transition boundaries were influenced by the geometry of the two-phase injection, the aspect ratio of the test micro-channels, and potentially the chip material as evidenced from comparisons with the results of previous studies. Three principal Segmented flow sub-regimes (1, 2, and 3) were identified on the basis of quantified topological characteristics, each closely correlated with two-phase flow pressure drop trends. Irregularity of the Segmented regimes and related influencing factors were addressed and discussed. The average bubble length associated with the Segmented flows scaled approximately with a power law of the liquid volumetric flow ratio, which depends on aspect ratio, liquid superficial velocity, and the injection system. A simplified semi-empirical geometric model of gas bubble and liquid plug volumes provided good estimates of liquid plug length for most of the segmented regime cases and for all test-channel aspect ratios. The two-phase flow pressure drop was measured for the square test channels. Each Segmented flow sub-regime was associated with different trends in the pressure drop scaled by the viscous scale. These trends were explained in terms of the quantified flow topology (measured gas bubble and liquid plug lengths) and the number of bubble/plug pairs. Significant quantitative differences were found between the two-phase pressure drop in the polymer micro-channels of this study and those obtained from previous glass

  1. Simplified recovery process of Ralstonia solanacearum-synthesized polyhydroxyalkanoates via chemical extraction complemented by liquid-liquid phase separation

    Directory of Open Access Journals (Sweden)

    Karine L. Macagnan

    Full Text Available Poly (3-hydroxybutyrate (P(3HB is the most studied thermoplastic biopolymer belonging to the polyhydroxyalkanoate (PHA family, the main features of which include rapid biodegradability and biocompatibility. The bioplastic recovery process is an important step during production and can directly influence the characteristics of PHAs. However, more efficient methods for the production of P(3HB are necessary to make it economically viable. The aim of the present study was to improve the standard, chloroform-based, extraction step for the recovery of P(3HB. The polymer was produced using a Ralstonia solanacearum strain. The following parameters were improved in the recovery process: heating time, separation method (filtration or liquid-liquid phase separation, biomass state (fresh or dry cell concentrate and the solvent:biomass ratio. By improving the chemical extraction of P(3HB we recovered 98% of the cumulative polymer and reduced the heating time by 75%. Furthermore, we improved the separation process and developed an extraction solution that was faster and more economical.

  2. Integration of phase separation with ultrasound-assisted salt-induced liquid-liquid microextraction for analyzing the fluoroquinones in human body fluids by liquid chromatography.

    Science.gov (United States)

    Wang, Huili; Gao, Ming; Wang, Mei; Zhang, Rongbo; Wang, Wenwei; Dahlgren, Randy A; Wang, Xuedong

    2015-03-15

    Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted salt-induced liquid-liquid microextraction for determination of five fluoroquinones (FQs) in human body fluids. The integrated device consisted of three simple HDPE components used to separate the extraction solvent from the aqueous phase prior to retrieving the extractant. A series of extraction parameters were optimized using the response surface method based on central composite design. Optimal conditions consisted of 945μL acetone extraction solvent, pH 2.1, 4.1min stir time, 5.9g Na2SO4, and 4.0min centrifugation. Under optimized conditions, the limits of detection (at S/N=3) were 0.12-0.66μgL(-1), the linear range was 0.5-500μgL(-1) and recoveries were 92.6-110.9% for the five FQs extracted from plasma and urine. The proposed method has several advantages, such as easy construction from inexpensive materials, high extraction efficiency, short extraction time, and compatibility with HPLC analysis. Thus, this method shows excellent prospects for sample pretreatment and analysis of FQs in human body fluids. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Thyroid function in children with growth hormone (GH deficiency during the initial phase of GH replacement therapy - clinical implications

    Directory of Open Access Journals (Sweden)

    Smyczynska Joanna

    2010-03-01

    Full Text Available Abstract Background Normal thyroid hormone secretion or appropriate L-thyroxine (L-T4 substitution is necessary for the optimal effect of the growth hormone (GH administration on growth rate. The decrease of free thyroxine (FT4 levels at recombinant human GH (rhGH therapy onset has been reported in several studies. The aim of the present study was to evaluate the effect of rhGH administration on thyrotropin (TSH and FT4 serum concentrations in children with GH deficiency (GHD during the 1st year of therapy, as well as to assess potential indications to thyroid hormone supplementation in them. Patients and methods The analysis involved data of 75 children (59 boys, 16 girls with disorders of GH secretion (GHD, neurosecretory dysfunction - NSD and partial GH inactivity (inactGH, who were treated with rhGH for - at least - one year. In all the children, body height and height velocity (HV were assessed before and after 1 year of therapy, while TSH, FT4, IGF-I and IGFBP-3 before treatment and after 3-6 months and 1 year of treatment. In the patients, who revealed hypothyroidism (HypoT, an appropriate L-T4 substitution was introduced immediately. The incidence of HypoT, occurring during the initial phase of rhGH therapy, was assessed, as well as its influence on the therapy effectiveness. Results Before rhGH substitution, there were no significant differences in either auxological indices or TSH and FT4 secretion, or IGF-I concentration and its bioavailability among the groups of patients. During the initial 3-6 months of rhGH administration, a significant decrease of FT4 serum concentration, together with a significant increase of IGF-I SDS and IGF-I/IGFBP-3 molar ratio was observed in all the studied groups. In 17 children, HypoT was diagnosed and L-T4 substitution was administered. Despite similar IGF-I secretion increase, the improvement of HV presented significantly lower in children with HypoT than in those who remained euthyroid all the time

  4. Feasibility analysis of two-phase MHD energy conversion for liquid metal cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Wu Qiao [Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR 97331 (United States)], E-mail: qiao@engr.orst.edu; Schubring, DuWayne L. [Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR 97331 (United States); Sienicki, James J. [Reactor Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2007-11-15

    A two-phase MHD energy conversion unit is proposed to a liquid metal cooled fast reactor. Using supercritical CO{sub 2} as the working fluid in the gas cycle without considering friction and heat losses, the optimized cycles efficiency is obtained, which is about 5% higher than that of the gas turbine Brayton cycle with the same regenerator/compressor configurations. Based on a simple MHD power analysis and the two-phase homogeneous flow model, the important system operational conditions were estimated. The results suggest that a liquid lead pump of at least 20% of the MHD power output is needed in order to convert the 400 MW reactor heat into electricity at the specified thermal efficiency, unless a mixture foam flow of void fraction greater than 80% is achievable at very high mixture velocity.

  5. Processing of removed Scholven residue in liquid phase at 600 atm

    Energy Technology Data Exchange (ETDEWEB)

    Reitz

    1942-02-26

    This report listed data of the preliminary hydrogenation and gasolinification of anhydrogenous and phenol-less S-middle oil obtained from processing Scholven residue in liquid phase. A petrol was produced, at 250 atm with catalyst 8376/6434, that had practically the same naphthene. It had a slightly higher aromatic content than compound petrol obtained from the preliminary hydrogenation and gasolinification step (8376/6434) of the processing of Scholven S-middle oil. This petrol's octane number was 1.5 units higher than that of the compound petrol. Comments point out that the difference was more noticeable when the associated liquid-phase petrols were mixed. The report then described the process in detail, including a table with all the relevant data. 1 table.

  6. Studies on two-phase ionic liquid-aqueous flows in small channels of various sizes

    Science.gov (United States)

    Tsaoulidis, Dimitrios; Chinaud, Maxime; Li, Qi; Angeli, Panagiota; University College London Team

    2014-11-01

    Two-phase flows in intensified small-scale systems find increasing applications in (bio)chemical analysis and synthesis, fuel cells, polymerisation, and separation processes (solvent extraction). Ionic liquids are emerging as a useful chemical in different areas of interest because of their unique properties such as negligible volatility and flammability, and good thermal and radiation stability. In this work, the hydrodynamic characteristics during plug flow have been investigated in detail. Experiments were carried out in Teflon channels of different sizes, i.e. 0.5, 1, and 2 mm internal diameter using two-phase systems relevant to spent nuclear fuel reprocessing, i.e. TBP/ionic liquid (30%, v/v)-nitric acid solutions. Important mixing characteristics and circulation patterns within the aqueous plugs have been studied by means of Particle Image Velocimetry (PIV). Finally, the mechanism of plug flow formation and the resulting plug size were investigated using Computational Fluid Dynamic (CFD).

  7. Partitioning Behavior of Papain in Ionic Liquids-Based Aqueous Two-Phase Systems

    Directory of Open Access Journals (Sweden)

    Zhiwen Bai

    2013-01-01

    Full Text Available This paper attempts to study and optimize the affinity partitioning conditions of papain in an aqueous two-phase system (ATPS. The effect of the amount of ionic liquids (ILs, the concentration of K2HPO4, temperature, pH, and the volume of papain solution were discussed concretely. The optimum conditions were determined as ionic liquid was 1.4 g and K2HPO4 was 1.4 g, the extraction efficiency of papain could reach 98.33% with pH unadjusted. The temperature and the pH of the solution are major parameters that influence the partitioning of protein in ILs-based ATPSs. The partition of papain to the IL-rich phase was enhanced by increasing the amount of ILs, the concentration of K2HPO4, and temperature, especially at its isoelectric point.

  8. Isotropic-to-nematic phase transition of liquid crystals confined in nanoemulsion droplets

    Science.gov (United States)

    Bono, S.; Takanishi, Y.; Yamamoto, J.

    2015-01-01

    We fabricated liquid crystalline nanoemulsions (LCNEs) by introducing low molecular weight liquid crystals (LMWLCs) into the core of nanoemulsions, and investigated the phase transition behavior of LMWLCs in the core part with the various weight ratios of LMWLCs to surfactants. The polarized dynamic light scattering measurement was performed to estimate the radii of LCNEs, and it is found that their radii can be controlled by the weight ratio of LMLCs to surfactant polymers. In the depolarized light scattering, it was revealed that the order of the isotropic-nematic phase transition behavior changes from the first order to biased second order with decreasing radius of LCNEs because of the three-dimensional confinement effect surrounded by an anchoring surface.

  9. Theoretical modeling of a two-phase thermosyphon assuming the liquids reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Zanardi, M.A. [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia; Leite, N.G.C. [Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil). Faculdade de Tecnologia. Dept. de Mecanica e Energia]. E-mail: nleite@fat.uerj.br

    2007-06-15

    A theoretical mod sling using the mass, momentum and energy conservation equations, about the intrinsic phenomena in the working of a cylindrical geometry two-phase thermosyphon operating on vertical was performed. The conservation equations were solved in steady-state operation for all the phases of the thermosyphon. Then model also assumed the presence of a liquid reservoir whose valves of the coefficient of heat transfer that determine the operation of functioning in the reservoir, were obtained from the correlation published in literature The set of conservation equations was solved by using the method of fl nite volumes. The results achieved were checked with experimental data from literature and also from specific experiments performed in laboratory. In a general view, the the oric results matched reasonably well with those ones from the experiments, and the observed deviation were assumed by a inadequate prevision of the reservoir model used, besides keeping a stable level of the reservoir of liquid. (author)

  10. Strength and reliability of low temperature transient liquid phase bonded Cu-Sn-Cu interconnects

    DEFF Research Database (Denmark)

    Brincker, Mads; Söhl, Stefan; Eisele, Ronald

    2017-01-01

    As power electronic devices have tendencies to operate at higher temperatures and current densities, the demand for reliable and efficient packaging technologies are ever increasing. This paper reports the studies on application of transient liquid phase (TLP) bonding of CuSnCu systems as a poten......As power electronic devices have tendencies to operate at higher temperatures and current densities, the demand for reliable and efficient packaging technologies are ever increasing. This paper reports the studies on application of transient liquid phase (TLP) bonding of CuSnCu systems....... Micro-sectioning and optical microscopy studies of the samples reveal that the TLP bonds show good homogeneity with a small number of voids at the interface. Energy dispersive X-ray analysis is applied to examine at what rates Sn is converted into CuSn intermetallics since a full conversion is critical...

  11. Poincaré-sphere representation of phase-mostly twisted nematic liquid crystal spatial light modulators

    Science.gov (United States)

    Durán, V.; Clemente, P.; Martínez-León, Ll; Climent, V.; Lancis, J.

    2009-08-01

    We establish necessary conditions in order to build a phase-only wavefront modulation system from a liquid crystal display. These conditions determine the dependence of the polarization state of the light emerging from the display on the addressing gray level. The analysis, which is carried out by means of the coherence-matrix formalism, includes the depolarization properties of the device. Two different types of polarization distributions at the output of the liquid crystal cells are found. This approach is applied to a twisted nematic liquid crystal display. In this case, an optimization algorithm must be designed in order to select the input polarization state that leads to the required distributions. We show that the Poincaré-sphere representation provides a convenient framework to design the optimization algorithm as it allows for a reduced number of degrees of freedom. This feature significantly decreases the computation time. Laboratory results are presented for a liquid crystal on silicon display showing a phase modulation depth greater than 2π rad with an intensity variation lower than 6%. In addition, a hybrid ternary modulation (HTM), an operation regime employed in holographic data storage, is achieved.

  12. Gas-liquid two-phase flow through packed bed reactors in microgravity

    Science.gov (United States)

    Motil, Brian Joseph

    Experimental results on flow pattern transitions, pressure drop and flow characteristics for cocurrent gas-liquid flow through packed bed reactors in microgravity is presented and analyzed. The pulse flow regime is shown to exist over a much wider range of gas and liquid flow rates when under microgravity conditions. A new model is developed to predict the transition from bubble flow to pulse flow based on the dimensionless Suratman number. The Suratman number is shown to represent the balance of forces at the pore level which determine the conditions necessary for the onset of pulse flow in the column. This model is then extended to normal gravity flows in the downward direction for fixed Bond numbers. A model to predict pressure drop in the absence of gravity is also presented. An additional pressure drop term is developed to extend the applicability of the Ergun equation to gas-liquid flow. This term represents the losses resulting from the dynamic interaction between the two phases and is superposed with the liquid viscous and inertia terms to represent the total pressure loss through a reactor bed in a microgravity environment. The modified two-phase Ergun equation is shown to provide good agreement with the experimental results.

  13. Oxidation desulfurization of fuel using pyridinium-based ionic liquids as phase-transfer catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dishun; Wang, Yanan; Duan, Erhong; Zhang, Juan

    2010-12-15

    In this work, several ionic liquids based on pyridinium cations are prepared. The ionic liquids are employed as phase-transfer catalysts (PTCs) for phase-transfer catalytic oxidation of dibenzothiophene (DBT) dissolved in n-octane. The partition coefficients of DBT between ionic liquids and n-octane are investigated. Then H{sub 2}O{sub 2}-formic acid is used as an oxidant and ionic liquids are used as PTCs. The reaction turns to be heterogeneous and desulfurization rate of DBT increased apparently. When IL ([BPy]HSO{sub 4}) is used as PTC, and the condition are: temperature is 60 C, time is 60 min, H{sub 2}O{sub 2}/sulfur molar ratio (O/S) is 4, the desulfurization rate reaches the maximum (93.3%), and the desulfurization of the real gasoline is also investigated, 87.7% of sulfur contents are removed under optima reaction conditions. The PTC [BPy]HSO{sub 4} can be recycled for five times without significant decrease in activity. (author)

  14. Ionic liquid-based dispersive liquid-liquid microextraction combined with functionalized magnetic nanoparticle solid-phase extraction for determination of industrial dyes in water.

    Science.gov (United States)

    Liang, Ning; Hou, Xiaohong; Huang, Peiting; Jiang, Chao; Chen, Lijuan; Zhao, Longshan

    2017-10-23

    N-butyl pyridinium bis((trifluoromethyl)sulfonyl)imide ([Hpy]NTf2) functionalized core/shell magnetic nanoparticles (MNPs, Fe3O4@SiO2@[Hpy]NTf2)) were prepared and applied as an adsorbent for magnetic solid phase extraction (MSPE) of three commonly used industrial dyes including malachite green, crystal violet and methylene blue. Extraction solution was mixed with 100 mg extraction material of Fe3O4@SiO2@[Hpy]NTf2, and 1 mL of acetonitrile was used to elute target analytes for further extraction and purification. [Hpy]NTf2 was used as extraction solution, and 500 μL methanol was selected as dispersive solvent in ionic liquid (IL) dispersive liquid-liquid microextraction (DLLME) method. After sonication for 5 min and centrifugation at 447 g for 10 min, 20 μL of sedimented phase was injected into HPLC-UV system. The limit of detection (LOD) and limit of quantification (LOQ) of current method were 0.03 and 0.16 μg·L(-1), respectively, which indicated the sensitivity was comparable or even superior to other reported methods. The relative recoveries of the target analytes ranged from 86.1% to 100.3% with relative standard deviations between 0.3% and 4.5%. The developed method has been successfully applied to determine the level of three industrial dyes in different water samples.

  15. Phase equilibrium study of the binary systems (N-hexyl-3-methylpyridinium tosylate ionic liquid + water, or organic solvent)

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula, E-mail: ula@ch.pw.edu.pl [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Thermodynamic Research Unit, School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4001 (South Africa); Krolikowski, Marek [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

    2011-10-15

    Highlights: > Synthesis, DSC, and measurements of phase equilibrium of N-hexyl-3-methylpyridinium tosylate. > Solvents used: water, alcohols, benzene, alkylbenzenes, and aliphatic hydrocarbons. > Correlation with UNIQUAC, Wilson and NRTL models. > Comparison with different tosylate-based ILs. - Abstract: The (solid + liquid) phase equilibrium (SLE) and (liquid + liquid) phase equilibrium (LLE) for the binary systems ionic liquid (IL) N-hexyl-3-methylpyridinium tosylate (p-toluenesulfonate), {l_brace}([HM{sup 3}Py][TOS] + water, or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol), or an aromatic hydrocarbon (benzene, toluene, or ethylbenzene, or propylbenzene), or an alkane (n-hexane, n-heptane, n-octane){r_brace} have been determined at ambient pressure using a dynamic method. Simple eutectic systems with complete miscibility in the liquid phase were observed for the systems involving water and alcohols. The phase equilibrium diagrams of IL and aromatic or aliphatic hydrocarbons exhibit eutectic systems with immiscibility in the liquid phase with an upper critical solution temperature as for most of the ILs. The correlation of the experimental data has been carried out using the UNIQUAC, Wilson and the non-random two liquid (NRTL) correlation equations. The results reported here have been compared with analogous phase diagrams reported by our group previously for systems containing the tosylate-based ILs.

  16. Determination of Trichloroethylene in Water by Liquid–Liquid Microextraction Assisted Solid Phase Microextraction

    OpenAIRE

    Mengliang Zhang; Harrington, Peter de B

    2015-01-01

    A method for the determination of trichloroethylene (TCE) in water using portable gas chromatography/mass spectrometry (GC/MS) was developed. A novel sample preparation method, liquid–liquid microextraction assisted solid phase microextraction (LLME–SPME), is introduced. In this method, 20 µL of hexane was added to 10 mL of TCE contaminated aqueous samples to assist headspace SPME. The extraction efficiency of SPME was significantly improved with the addition of minute amounts of organic solv...

  17. The liquid phase oxidation of n-butane: a search for plausible mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, C.C. [Celanese Ltd., TX (United States). Corpus Christi Technical Center

    1998-12-31

    This articles deals with an approach that has given some key information about the mechanisms of the liquid phase oxidation of butane to acetic acid. This procedure has been developed over the last 34 years; however, much of what will be discussed represents a synthesis of previous insights. Many of the observations are relatively recent and have not been previously published. In principle, this approach should be applicable to many oxidation processes. (orig.)

  18. Physico-Chemical Properties and Phase Behaviour of Pyrrolidinium-Based Ionic Liquids

    OpenAIRE

    Urszula Domańska

    2010-01-01

    A review of the relevant literature on 1-alkyl-1-methylpyrrolidinium-based ionic liquids has been presented. The phase diagrams for the binary systems of {1-ethyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate) [EMPYR][CF3SO3] + water, or + 1-butanol} and for the binary systems of {1-propyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate) [PMPYR][CF3SO3] + water, or + an alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol)} have been determined at atmospheric pressure usi...

  19. Soot and liquid-phase fuel distributions in a newly designed optically accessible DI diesel engine

    Science.gov (United States)

    Dec, J. E.; Espey, C.

    1993-10-01

    Two-dimensional (2-D) laser-sheet imaging has been used to examine the soot and liquid-phase fuel distributions in a newly designed, optically accessible, direct-injection diesel engine of the heavy-duty size class. The design of this engine preserves the intake port geometry and basic dimensions of a Cummins N-series production engine. It also includes several unique features to provide considerable optical access. Liquid-phase fuel and soot distribution studies were conducted at a medium speed (1,200 rpm) using a Cummins closed-nozzle fuel injector. The scattering was used to obtain planar images of the liquid-phase fuel distribution. These images show that the leading edge of the liquid-phase portion of the fuel jet reaches a maximum length of 24 mm, which is about half the combustion bowl radius for this engine. Beyond this point virtually all the fuel has vaporized. Soot distribution measurements were made at a high load condition using three imaging diagnostics: natural flame luminosity, 2-D laser-induced incandescence, and 2-D elastic scattering. This investigation showed that the soot distribution in the combusting fuel jet develops through three stages. First, just after the onset of luminous combustion, soot particles are small and nearly uniformly distributed throughout the luminous region of the fuel jet. Second, after about 2 crank angle degrees a pattern develops of a higher soot concentration of larger sized particles in the head vortex region of the jet and a lower soot concentration of smaller sized particles upstream toward the injector. Third, after fuel injection ends, both the soot concentration and soot particle size increase rapidly in the upstream portion of the fuel jet.

  20. Spiral phase plate based on polymer dispersed liquid crystal for wide visible band applications.

    Science.gov (United States)

    Wu, Shing-Trong; Fuh, Andy Ying-Guey

    2014-09-01

    This study demonstrates helical wave fronts via a spiral phase plate based on polymer dispersed liquid crystals (PDLCs). Because the PDLC is electric tunable, the plate can be used in a wide visible band. In addition, if the probe beam deviates from the center of the sample, some of the light propagates out of the sectors. We propose some of the applications for the results.

  1. High Contacting Efficience Carrier Structures & Porcesses for Liquid Phase Regenerable Desulfurization of Logistic Fuels

    Science.gov (United States)

    2011-02-21

    Phase Regenerable Desulfurization of Logistic Fuels 5a. CONTRACT NUMBER Sb. GRANT NUMBER N00014-06-1-1165 6c. PROGRAM ELEMENT NUMBER 6. AUTHOR...developed and characterized. The adsorbent’s formulation, preparation procedure, desulfurization conditions and regeneration procedure have established and...enables novel process design for the logistic fuel desulfurization . 15. SUBJECT TERMS desulfurization , liquid fuel, silver, titania 16. SECURITY

  2. Membrane curvature enables N-Ras lipid anchor sorting to liquid-ordered membrane phases

    DEFF Research Database (Denmark)

    Larsen, Jannik Bruun; Jensen, Martin Borch; Bhatia, Vikram Kjøller

    2015-01-01

    Trafficking and sorting of membrane-anchored Ras GTPases are regulated by partitioning between distinct membrane domains. Here, in vitro experiments and microscopic molecular theory reveal membrane curvature as a new modulator of N-Ras lipid anchor and palmitoyl chain partitioning. Membrane...... curvature was essential for enrichment in raft-like liquid-ordered phases; enrichment was driven by relief of lateral pressure upon anchor insertion and most likely affects the localization of lipidated proteins in general....

  3. A Heat Transfer Investigation of Liquid and Two-Phase Methane

    Science.gov (United States)

    VanNoord, Jonathan

    2010-01-01

    A heat transfer investigation was conducted for liquid and two-phase methane. The tests were conducted at the NASA Glenn Research Center Heated Tube Facility (HTF) using resistively heated tube sections to simulate conditions encountered in regeneratively cooled rocket engines. This testing is part of NASA s Propulsion and Cryogenics Advanced Development (PCAD) project. Nontoxic propellants, such as liquid oxygen/liquid methane (LO2/LCH4), offer potential benefits in both performance and safety over equivalently sized hypergolic propulsion systems in spacecraft applications. Regeneratively cooled thrust chambers are one solution for high performance, robust LO2/LCH4 engines, but cooling data on methane is limited. Several test runs were conducted using three different diameter Inconel 600 tubes, with nominal inner diameters of 0.0225-, 0.054-, and 0.075-in. The mass flow rate was varied from 0.005 to 0.07 lbm/sec. As the current focus of the PCAD project is on pressure fed engines for LO2/LCH4, the average test section outlet pressures were targeted to be 200 psia or 500 psia. The heat flux was incrementally increased for each test condition while the test section wall temperatures were monitored. A maximum average heat flux of 6.2 Btu/in.2 sec was achieved and, at times, the temperatures of the test sections reached in excess of 1800 R. The primary objective of the tests was to produce heat transfer correlations for methane in the liquid and two-phase regime. For two-phase flow testing, the critical heat flux values were determined where the fluid transitions from nucleate boiling to film boiling. A secondary goal of the testing was to measure system pressure drops in the two-phase regime.

  4. Single-reactor process for producing liquid-phase organic compounds from biomass

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A.; Simonetti, Dante A.; Kunkes, Edward L.

    2015-12-08

    Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

  5. Single-reactor process for producing liquid-phase organic compounds from biomass

    Science.gov (United States)

    Dumesic, James A [Verona, WI; Simonetti, Dante A [Middleton, WI; Kunkes, Edward L [Madison, WI

    2011-12-13

    Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

  6. Bond orientational order in the blue phases of chiral liquid crystals

    OpenAIRE

    Longa, Lech; Trebin, Hans-Rainer

    1993-01-01

    It is proposed to describe blue phases by two order parameters: the standard alignment tensor field Q αβ(r) and a bond orientational tensor order parameter of octahedral point group symmetry scrO(432). The yet mysterious blue fog then emerges as a liquid of purely cubic bond orientational order. In the transition from the cubic blue phases to the blue fog the cubic space group symmetry is being reduced to its octahedral factor group. Because of the new order parameter the scrO 5(scr...

  7. Multistable Phase-Retardation Plate Based on Gelator-Doped Liquid Crystals

    Science.gov (United States)

    Ying-Guey Fuh, Andy; Chiang, Jou-Ting; Chien, Yu-Shein; Chang, Chih-Juang; Lin, Hui-Chi

    2012-07-01

    This work demonstrates a multistable, large phase-retardation plate using gelator-doped liquid crystals (LCs). Multistability is achieved by forming a rubbery LC gel at room temperature. Experimentally, the phase retardation (PR) of an LC-gel film can be varied and fixed by the thermoreversible association and dissociation of the gelator molecules. The PR of the LC plate ranging from 0.3-3.7π can be electrically controllable within 10 V. Half-wave and quarter-wave LC plates were also produced at applied voltages of 3.5 and 6.3 V, respectively. Their properties were examined and found to be stable.

  8. Berry Phase of Light under Bragg Reflection by Chiral Liquid-Crystal Media

    Science.gov (United States)

    Barboza, Raouf; Bortolozzo, Umberto; Clerc, Marcel G.; Residori, Stefania

    2016-07-01

    A Berry phase is revealed for circularly polarized light when it is Bragg reflected by a chiral liquid-crystal medium of the same handedness. By using a chiral nematic layer we demonstrate that if the input plane of the layer is rotated with respect to a fixed reference frame, a geometric phase effect occurs for the circularly polarized light reflected by the periodic helical structure of the medium. Theory and numerical simulations are supported by an experimental observation, disclosing novel applications in the field of optical manipulation and fundamental optical phenomena.

  9. Gas-liquid two-phase flows in double inlet cyclones for natural gas separation

    DEFF Research Database (Denmark)

    Yang, Yan; Wang, Shuli; Wen, Chuang

    2017-01-01

    The gas-liquid two-phase flow within a double inlet cyclone for natural gasseparation was numerically simulated using the discrete phase model. The numericalapproach was validated with the experimental data, and the comparison resultsagreed well with each other. The simulation results showed...... that the strong swirlingflow produced a high centrifugal force to remove the particles from the gas mixture.The larger particles moved downward on the internal surface and were removeddue to the outer vortex near the wall. Most of the tiny particles went into the innervortex zones and escaped from the up...

  10. Berry Phase of Light under Bragg Reflection by Chiral Liquid-Crystal Media.

    Science.gov (United States)

    Barboza, Raouf; Bortolozzo, Umberto; Clerc, Marcel G; Residori, Stefania

    2016-07-29

    A Berry phase is revealed for circularly polarized light when it is Bragg reflected by a chiral liquid-crystal medium of the same handedness. By using a chiral nematic layer we demonstrate that if the input plane of the layer is rotated with respect to a fixed reference frame, a geometric phase effect occurs for the circularly polarized light reflected by the periodic helical structure of the medium. Theory and numerical simulations are supported by an experimental observation, disclosing novel applications in the field of optical manipulation and fundamental optical phenomena.

  11. Anisotropic solid-liquid interface kinetics in silicon: an atomistically informed phase-field model

    Science.gov (United States)

    Bergmann, S.; Albe, K.; Flegel, E.; Barragan-Yani, D. A.; Wagner, B.

    2017-09-01

    We present an atomistically informed parametrization of a phase-field model for describing the anisotropic mobility of liquid-solid interfaces in silicon. The model is derived from a consistent set of atomistic data and thus allows to directly link molecular dynamics and phase field simulations. Expressions for the free energy density, the interfacial energy and the temperature and orientation dependent interface mobility are systematically fitted to data from molecular dynamics simulations based on the Stillinger-Weber interatomic potential. The temperature-dependent interface velocity follows a Vogel-Fulcher type behavior and allows to properly account for the dynamics in the undercooled melt.

  12. Separation of Flue Gas Components by SILP (Supported Ionic Liquid-Phase) Absorbers

    DEFF Research Database (Denmark)

    Thomassen, P.; Kunov-Kruse, Andreas Jonas; Mossin, Susanne L.

    2013-01-01

    -Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow processes for flue gas cleaning....... The results show that CO2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperature, pressure and gas concentration. © 2012...

  13. The binary eutectic of NSAIDS and two-phase liquid system for enhanced membrane permeation.

    Science.gov (United States)

    Yuan, Xudong; Capomacchia, A C

    2005-01-01

    The eutectic properties of binary mixtures of some nonsteroidal anti-inflammatory drugs (NSAIDs) with ibuprofen were studied using differential scanning calorimetry (DSC) and phase equilibrium diagrams. The melting points of selected NSAIDs were significantly depressed due to binary eutectic formation with ibuprofen. Ketoprofen and ibuprofen were selected to study the effect of eutectic formation on membrane permeation using Franz diffusion cells and snake skin as the model membrane. The presence of aqueous isopropyl alcohol (IPA) was necessary to completely transform the solid drugs into an oily state at ambient temperature. As much as the 99.6% of ibuprofen and the 88.8% of ketoprofen added were found in the oily phase of the two-phase liquid system formed when aqueous IPA was added to the eutectic mixture. Due to the high drug concentration in the oily phase, and maximum thermodynamic activity, the two-phase liquid system showed enhanced membrane permeation rates of ibuprofen (37.5 microg/cm2/hr) and ketoprofen (33.4 microg/cm2/hr) compared to other reference preparations used.

  14. Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Moretto, L.G.; Elliott, J.B.; Phair, L. [Lawrence Berkeley National Laboratory, Nuclear Science Division (United States)

    2003-07-01

    In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A {approx} 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)

  15. Dynamical heterogeneity in the supercooled liquid state of the phase change material GeTe.

    Science.gov (United States)

    Sosso, Gabriele C; Colombo, Jader; Behler, Jörg; Del Gado, Emanuela; Bernasconi, Marco

    2014-11-26

    A contending technology for nonvolatile memories of the next generation is based on a remarkable property of chalcogenide alloys known as phase change materials, namely their ability to undergo a fast and reversible transition between the amorphous and crystalline phases upon heating. The fast crystallization has been ascribed to the persistence of a high atomic mobility in the supercooled liquid phase, down to temperatures close to the glass transition. In this work we unravel the atomistic, structural origin of this feature in the supercooled liquid state of GeTe, a prototypical phase change compound, by means of molecular dynamic simulations. To this end, we employed an interatomic potential based on a neural network framework, which allows simulating thousands of atoms for tens of ns by keeping an accuracy close to that of the underlying first-principles framework. Our findings demonstrate that the high atomic mobility is related to the presence of clusters of slow and fast moving atoms. The latter contain a large fraction of chains of homopolar Ge-Ge bonds, which at low temperatures have a tendency to move by discontinuous cage-jump rearrangements. This structural fingerprint of dynamical heterogeneity provides an explanation of the breakdown of the Stokes-Einstein relation in GeTe, which is the ultimate origin of the fast crystallization of phase change materials exploited in the devices.

  16. Thermodynamics and Phase Behavior of Phosphonated Block Copolymers Containing Ionic Liquids

    Science.gov (United States)

    Jung, Ha Young; Park, Moon Jeong

    Charge-containing copolymers have drawn intensive attention in recent years for their uses in wide range of electrochemical devices such as fuel cells, lithium batteries and actuators. Particularly, the creation of microphase-separated morphologies in such materials by designing them in block and graft configurations has been the subject of extensive studies, in order to establish a synergistic means of optimizing ion transport properties and mechanical integrity. Interest in this topic has been further stimulated by intriguing phase behavior from charge-containing polymers, which was not projected from conventional phase diagrams of non-ionic polymers. Herein, we investigate thermodynamics and phase behavior of a set of phosphonated block copolymers. By synthesizing low-molecular weight samples with degree of polymerization (N) random phase approximation. We further examined the systems by adding various ionic liquids, where noticeable increases in χ values and modulated microphase separation behavior were observed. The morphology-conductivity relationship has been elucidated by taking into account the segmental motion of polymer chains, volume of conducting phases, and the molecular interactions between phosphonated polymer chains and cations of ionic liquids.

  17. Reduced graphene oxide directed self-assembly of phospholipid monolayers in liquid and gel phases.

    Science.gov (United States)

    Rui, Longfei; Liu, Jiaojiao; Li, Jingliang; Weng, Yuyan; Dou, Yujiang; Yuan, Bing; Yang, Kai; Ma, Yuqiang

    2015-05-01

    The response of cell membranes to the local physical environment significantly determines many biological processes and the practical applications of biomaterials. A better understanding of the dynamic assembly and environmental response of lipid membranes can help understand these processes and design novel nanomaterials for biomedical applications. The present work demonstrates the directed assembly of lipid monolayers, in both liquid and gel phases, on the surface of a monolayered reduced graphene oxide (rGO). The results from atomic force microscopy indicate that the hydrophobic aromatic plane and the defect holes due to reduction of GO sheets, along with the phase state and planar surface pressure of lipids, corporately determine the morphology and lateral structure of the assembled lipid monolayers. The DOPC molecules, in liquid phase, probably spread over the rGO surface with their tails associating closely with the hydrophobic aromatic plane, and accumulate to form circles of high area surrounding the defect holes on rGO sheets. However, the DPPC molecules, in gel phase, prefer to form a layer of continuous membrane covering the whole rGO sheet including defect holes. The strong association between rGO sheets and lipid tails further influences the melting behavior of lipids. This work reveals a dramatic effect of the local structure and surface property of rGO sheets on the substrate-directed assembly and subsequent phase behavior of the supported lipid membranes. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. A phase 2 trial of long-acting TransCon growth hormone in adult GH deficiency

    DEFF Research Database (Denmark)

    Höybye, Charlotte; Pfeiffer, Andreas F H; Ferone, Diego

    2017-01-01

    was reported. No treatment-emergent anti-growth hormone binding antibodies were detected. TransCon GH demonstrated a linear, dose-dependent increase in growth hormone exposure without substantial accumulation. Growth hormone maximum serum concentration and insulin-like growth factor 1 exposure were similar......TransCon growth hormone is a sustained release human growth hormone prodrug in development in which unmodified growth hormone is transiently linked to a carrier molecule. It is intended as an alternative to daily growth hormone in the treatment of growth hormone deficiency. This was a multi......-center, randomized, open-label, active-controlled trial designed to compare the safety (including tolerability and immunogenicity), pharmacokinetics, and pharmacodynamics of three doses of weekly TransCon GH to daily growth hormone (Omnitrope). Thirty-seven adult males or females diagnosed with adult growth hormone...

  19. Liquid phase diffusion bonding of A1070 by using metal formate coated Zn sheet

    Science.gov (United States)

    Ozawa, K.; Koyama, S.; shohji, I.

    2017-05-01

    Aluminium alloy have high strength and easily recycle due to its low melting point. Therefore, aluminium is widely used in the manufacturing of cars and electronic devices. In recent years, the most common way for bonding aluminium alloy is brazing and friction stir welding. However, brazing requires positional accuracy and results in the formation of voids by the flax residue. Moreover, aluminium is an excellent heat radiating and electricity conducting material; therefore, it is difficult to bond together using other bonding methods. Because of these limitations, liquid phase diffusion bonding is considered to the suitable method for bonding aluminium at low temperature and low bonding pressure. In this study, the effect of metal formate coating processing of zinc surface on the bond strength of the liquid phase diffusion bonded interface of A1070 has been investigated by SEM observation of the interfacial microstructures and fractured surfaces after tensile test. Liquid phase diffusion bonding was carried out under a nitrogen gas atmosphere at a bonding temperature of 673 K and 713 K and a bonding load of 6 MPa (bonding time: 15 min). As a result of the metal formate coating processing, a joint having the ultimate tensile strength of the base aluminium was provided. It is hypothesized that this is because metallic zinc is generated as a result of thermal decomposition of formate in the bonded interface at lower bonding temperatures.

  20. On intermittent flow characteristics of gas–liquid two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Thaker, Jignesh; Banerjee, Jyotirmay, E-mail: jbaner@gmail.com

    2016-12-15

    Highlights: • Unified correlations for intermittent flow characteristics are developed. • Influence of inflow conditions on intermittent flow characteristics is analysed. • Developed correlations can be used for effective design of piping components. - Abstract: Flow visualisation experiments are reported for intermittent regime of gas–liquid two-phase flow. Intermittent flow characteristics, which include plug/slug frequency, liquid plug/slug velocity, liquid plug/slug length, and plug/slug bubble length are determined by image processing of flow patterns captured at a rate of 1600 frames per second (FPS). Flow characteristics are established as a function of inlet superficial velocity of both the phases (in terms of Re{sub SL} and Re{sub SG}). The experimental results are first validated with the existing correlations for slug flow available in literature. It is observed that the correlations proposed in literature for slug flow do not accurately predict the flow characteristics in the plug flow regime. The differences are clearly highlighted in this paper. Based on the measured database for both plug and slug flow regime, modified correlations for the intermittent flow regime are proposed. The correlations reported in the present paper, which also include plug flow characteristics will aid immensely to the effective design and optimization of operating conditions for safer operation of two-phase flow piping systems.

  1. One- and two-phase anaerobic digestion of ley crop silage with and without liquid recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Nordberg, Aa.

    1996-10-01

    In this study the effects of liquid recirculation on hydrolysis and methanogenesis in one- and two-phase biogas processes were investigated in comparison with water-diluted processes. The operation of a water-diluted one-phase process resulted in process imbalances at a low loading rate. In a water-diluted two-phase process the fibre degrading capability was lost. The reason for the poor process performance was due to a deficiency in trace elements, since the supplementation of cobalt resulted in an increased conversion rate of acetate. The recirculation of process liquid resulted in an accumulation of different compounds which initially stabilized one-phase processes and stimulated the hydrolysis and the methane production in the liquefaction-acidogenesis stage of a two-phase process. However, upon continuous recirculation the concentration of free ammonia reached toxic levels, which resulted in a decrease in the methane yield both in the methanogenic reactor of the two-phase process and in the one-phase process. Due to the decreased methane production, acids started to accumulate which subsequently inhibited the hydrolysis in the one-phase process. The systematic variation in the processes were evaluated using principal component analysis and principal component regression. The interpretation of the dynamic behaviour of the processes was facilitated by the use of score plots and loading plots. The results indicate that ley crops do not meet the nutrient requirements of the bacteria in anaerobic digestion. Thus, the low content of trace elements and the high content of protein which subsequently will cause toxic levels of ammonia in digesting system with low water consumption, suggests co-digestion with supplementary feedstocks. 95 refs, 5 figs, 3 tabs

  2. Observation of NanoDNA Liquid Crystal Phases from Four Base Pair Duplexes at Subambient Temperatures

    Science.gov (United States)

    Smith, Gregory; Fraccia, Tommaso; Bellini, Tommaso; Walba, David; Clark, Noel

    2014-03-01

    Based upon conventional Onsager model considerations, liquid crystal (LC) formation in DNA-water mixtures was originally thought to be impossible for DNA polymers of very short length (discovery of chiral nematic (N*), columnar CU and C2 LC phases in NanoDNA oligomers as short as 6 bases in length and have since described additional LC phases involving DNA with random sequences and various blunt or sticky-end duplex architecture, all in the regime of motif where hydrophobic forces or hydrogen bond mediated base-pairing enable unusually short polymers to stack into functionally longer units that permit them to exhibit LC phase behavior. We report now the existence of LC phases of ultra short duplexed NanoDNA, 4 bases in length, in blunt-end, sticky-end and random sequence configurations, all observed at temperatures of ~ 5 °C and not stable >13-15 °C. These oligomers demonstrate an unusual wealth of phase behavior, including the typical N*, CU and C2 phases as well as higher order dark and bright phases, including what we believe to be a Blue Phase. Grant support: NSF DMR 1207606 and NSF MRSEC DMR 0820579.

  3. The premenstrual phase and reactions to aversive events: a study of hormonal influences on emotionality.

    NARCIS (Netherlands)

    Goozen, van St.H.M.; Frijda, N.H.; Wiegant, V.M.; Endert, E.; Poll, van de N.E.

    1996-01-01

    Fifty-eight normal cycle, healthy women were confronted with an aversive, anger-provoking situation in the laboratory. Eighteen women were tested in their follicular phase. A further 40 women were tested in the premenstrual phase, half of whom reported suffering from complaints of premenstrual

  4. A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification

    Science.gov (United States)

    Choi, Dongwhi; Lee, Donghyeon; Sung Kim, Dong

    2015-10-01

    In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two-phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid-liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

  5. Photo-Induced Phase Transitions to Liquid Crystal Phases: Influence of the Chain Length from C8E4 to C14E4

    Directory of Open Access Journals (Sweden)

    Simone Techert

    2009-09-01

    Full Text Available Photo-induced phase transitions are characterized by the transformation from phase A to phase B through the absorption of photons. We have investigated the mechanism of the photo-induced phase transitions of four different ternary systems CiE4/alkane (i with n = 8, 10, 12, 14; cyclohexane/H2O. We were interested in understanding the effect of chain length increase on the dynamics of transformation from the microemulsion phase to the liquid crystal phase. Applying light pump (pulse/x-ray probe (pulse techniques, we could demonstrate that entropy and diffusion control are the driving forces for the kind of phase transition investigated.

  6. Adsorbent phases with nanomaterials for in-tube solid-phase microextraction coupled on-line to liquid nanochromatography.

    Science.gov (United States)

    González-Fuenzalida, R A; López-García, E; Moliner-Martínez, Y; Campíns-Falcó, P

    2016-02-05

    Following the present trends in miniaturization, a methodology that combines on-line In-Tube Solid-Phase Microextraction (IT-SPME) with Liquid Nanochromatography (nano-LC) and UV-vis diode array detection (DAD) was developed. This coupling was achieved by using two interconnected valves (i.e. conventional and micro-automatic valves) in the system of injection. As for IT-SPME, different materials, containing in some cases nanostructures or nanoparticles and in other cases polymeric adsorbent phases immobilized on capillary columns, were tested in order to improve extraction efficiencies of organic compounds; diclofenac was selected as the target analyte. Additionally, the transfer time of the sample between the two injection valves, as well as the lengths and the internal diameters of the capillary columns, was optimized. Under the selected conditions, the resulting IT-SPME-nano-LC-DAD method showed great potential to become a powerful analytical tool as it was successfully applied to the determination of diclofenac in pharmaceutical and water samples. For comparison purposes, IT-SPME coupled to Capillary Liquid Chromatography (Cap-LC) was used. The extraction yield of diclofenac reached near 80%, a high value for techniques that involve IT-SPME. Good accuracy (recoveries near 100%) and precision (4% RSD) were obtained. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Functional design criteria for Project W-252, Phase II Liquid Effluent Treatment and Disposal: Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Hatch, C.E.

    1994-11-10

    This document provides the functional design criteria required for the Phase 2 Liquid Effluent Treatment and Disposal Project, Project W-252. Project W-252 shall provide new facilities and existing facility modifications required to implement Best Available Technology/All Known, Available, and Reasonable Methods of Prevention, Control, and Treatment (BAT/AKART) for the 200 East Phase II Liquid Effluent Streams. The project will also provide a 200 East Area Phase II Effluent Collection System (PTECS) for connection to a disposal system for relevant effluent streams to which BAT/AKART has been applied. Liquid wastestreams generated in the 200 East Area are currently discharged to the soil column. Included in these wastestreams are cooling water, steam condensate, raw water, and sanitary wastewaters. It is the policy of the DOE that the use of soil columns to treat and retain radionuclides and nonradioactive contaminants be discontinued at the earliest practical time in favor of wastewater treatment and waste minimization. In 1989, the DOE entered into an interagency agreement with Ecology and EPA. This agreement is referred to as the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). Project W-252 is one of the projects required to achieve the milestones set forth in the Tri-Party Agreement. One of the milestones requires BAT/AKART implementation for Phase II streams by October 1997. This Functional Design Criteria (FDC) document provides the technical baseline required to initiate Project W-252 to meet the Tri-Party Agreement milestone for the application of BAT/AKART to the Phase II effluents.

  8. Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows

    Directory of Open Access Journals (Sweden)

    Xia Wang

    2012-12-01

    Full Text Available In modeling gas-liquid two-phase flows, the concept of flow regimes has been widely used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are flow regime dependent. Current nuclear reactor safety analysis codes, such as RELAP5, classify flow regimes using flow regime maps or transition criteria that were developed for steady-state, fully-developed flows. As two-phase flows are dynamic in nature, it is important to model the flow regime transitions dynamically to more accurately predict the two-phase flows. The present work aims to develop a dynamic modeling strategy to determine flow regimes in gas-liquid two-phase flows through introduction of interfacial area transport equations (IATEs within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation of the interfacial area, fluid particle (bubble or liquid droplet disintegration, boiling and evaporation, and the destruction of the interfacial area, fluid particle coalescence and condensation. For flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shapes, namely group-1 and group-2 bubbles. A preliminary approach to dynamically identify the flow regimes is discussed, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration. The flow regime predicted with this method shows good agreement with the experimental observations.

  9. Dynamic Modeling of the Two-Phase Leakage Process of Natural Gas Liquid Storage Tanks

    Directory of Open Access Journals (Sweden)

    Xia Wu

    2017-09-01

    Full Text Available The leakage process simulation of a Natural Gas Liquid (NGL storage tank requires the simultaneous solution of the NGL’s pressure, temperature and phase state in the tank and across the leak hole. The methods available in the literature rarely consider the liquid/vapor phase transition of the NGL during such a process. This paper provides a comprehensive pressure-temperature-phase state method to solve this problem. With this method, the phase state of the NGL is predicted by a thermodynamic model based on the volume translated Peng-Robinson equation of state (VTPR EOS. The tank’s pressure and temperature are simulated according to the pressure-volume-temperature and isenthalpic expansion principles of the NGL. The pressure, temperature, leakage mass flow rate across the leak hole are calculated from an improved Homogeneous Non-Equilibrium Diener-Schmidt (HNE-DS model and the isentropic expansion principle. In particular, the improved HNE-DS model removes the ideal gas assumption used in the original HNE-DS model by using a new compressibility factor developed from the VTPR EOS to replace the original one derived from the Clausius-Clayperon equation. Finally, a robust procedure of simultaneously solving the tank model and the leak hole model is proposed and the method is validated by experimental data. A variety of leakage cases demonstrates that this method is effective in simulating the dynamic leakage process of NGL tanks under critical and subcritical releasing conditions associated with vapor/liquid phase change.

  10. Hydrogels with a Memory: Dual-Responsive, Organometallic Poly(ionic liquid)s with Hysteretic Volume-Phase Transition

    Science.gov (United States)

    2017-01-01

    We report on the synthesis and structure–property relations of a novel, dual-responsive organometallic poly(ionic liquid) (PIL), consisting of a poly(ferrocenylsilane) backbone of alternating redox-active, silane-bridged ferrocene units and tetraalkylphosphonium sulfonate moieties in the side groups. This PIL is redox responsive due to the presence of ferrocene in the backbone and also exhibits a lower critical solution temperature (LCST)-type thermal responsive behavior. The LCST phase transition originates from the interaction between water molecules and the ionic substituents and shows a concentration-dependent, tunable transition temperature in aqueous solution. The PIL’s LCST-type transition temperature can also be influenced by varying the redox state of ferrocene in the polymer main chain. As the polymer can be readily cross-linked and is easily converted into hydrogels, it represents a new dual-responsive materials platform. Interestingly, the as-formed hydrogels display an unusual, strongly hysteretic volume-phase transition indicating useful thermal memory properties. By employing the dispersing abilities of this cationic PIL, CNT-hydrogel composites were successfully prepared. These hybrid conductive composite hydrogels showed bi-stable states and tunable resistance in heating–cooling cycles. PMID:28654756

  11. Systematic and meta-analytic review of research examining the impact of menstrual cycle phase and ovarian hormones on smoking and cessation.

    Science.gov (United States)

    Weinberger, Andrea H; Smith, Philip H; Allen, Sharon S; Cosgrove, Kelly P; Saladin, Michael E; Gray, Kevin M; Mazure, Carolyn M; Wetherington, Cora Lee; McKee, Sherry A

    2015-04-01

    To determine the effect of ovarian hormones on smoking, we conducted a systematic review of menstrual cycle effects on smoking (i.e., ad lib smoking, smoking topography, and subjective effects) and cessation-related behaviors (i.e., cessation, withdrawal, tonic craving, and cue-induced craving). Thirty-six papers were identified on MEDLINE that included a menstrual-related search term (e.g., menstrual cycle, ovarian hormones), a smoking-related search term (e.g., smoking, nicotine), and met all inclusion criteria. Thirty-two studies examined menstrual phase, 1 study measured hormone levels, and 3 studies administered progesterone. Sufficient data were available to conduct meta-analyses for only 2 of the 7 variables: withdrawal and tonic craving. Women reported greater withdrawal during the luteal phase than during the follicular phase, and there was a nonsignificant trend for greater tonic craving in the luteal phase. Progesterone administration was associated with decreased positive and increased negative subjective effects of nicotine. Studies of menstrual phase effects on the other outcome variables were either small in number or yielded mixed outcomes. The impact of menstrual cycle phase on smoking behavior and cessation is complicated, and insufficient research is available upon which to conduct meta-analyses on most smoking outcomes. Future progress will require collecting ovarian hormone levels to more precisely quantify the impact of dynamic changes in hormone levels through the cycle on smoking behavior. Clarifying the relationship between hormones and smoking-particularly related to quitting, relapse, and medication response-could determine the best type and timing of interventions to improve quit rates for women. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. The relationship among acute-phase response proteins, cytokines and hormones in cachectic patients with colon cancer

    Directory of Open Access Journals (Sweden)

    Dulger Ahmet

    2010-09-01

    Full Text Available Abstract Backgraund Acute-phase response proteins (APRP, cytokines and hormones have been claimed to be an independent prognostic factor of malignancies, however the basis for their association with prognosis remains unexplained. We suggest that in colon malignancies, as similar to pancreatic and lung cancers, changes in APRP are associated with angiogenesis. Methods C-reactive protein (CRP, albumin, IL-1α, IL-1β, IL-6, IL-8, IL-10, TNF-α, midkine, VEGF-A, VEGF-C, leptin, adiponectin, and ghrelin serum levels are studied in 126 colon cancer patients and 36 healthy subjects. Results We found statistically significant difference and correlations between two groups. We found significantly higher serum CRP, IL-1α, IL-1β, IL-6, IL-8, IL-10, TNF-α, VEGF-A, VEGF-C and leptin concentrations in patients relative to controls (p Conclusions Cachexia in patients with colon cancers is associated with changes in APRP, cytokines and hormone concentrations. These biomarkers and cachexia together have a direct relationship with accelerated angiogenesis. This may lead to a connection between the outcomes in malignancies and the biomarkers.

  13. Study on the Microstructure and Liquid Phase Formation in a Semisolid Gray Cast Iron

    Science.gov (United States)

    Benati, Davi Munhoz; Ito, Kazuhiro; Kohama, Kazuyuki; Yamamoto, Hajime; Zoqui, Eugenio José

    2017-10-01

    The development of high-quality semisolid raw materials requires an understanding of the phase transformations that occur as the material is heated up to the semisolid state, i.e., its melting behavior. The microstructure of the material plays a very important role during semisolid processing as it determines the flow behavior of the material when it is formed, making a thorough understanding of the microstructural evolution essential. In this study, the phase transformations and microstructural evolution in Fe2.5C1.5Si gray cast iron specially designed for thixoforming processes as it was heated to the semisolid state were observed using in situ high-temperature confocal laser scanning microscopy. At room temperature, the alloy has a matrix of pearlite and ferrite with fine interdendritic type D flake graphite. During heating, the main transformations observed were graphite precipitation inside the grains and at the austenite grain boundaries; graphite flakes and graphite precipitates growing and becoming coarser with the increasing temperature; and the beginning of melting at around 1413 K to 1423 K (1140 °C to 1150 °C). Melting begins with the eutectic phase ( i.e., the carbon-rich phase) and continues with the primary phase (primary austenite), which is consumed as the temperature increases. Melting of the eutectic phase composed by coarsened interdendritic graphite flakes produced a semi-continuous liquid network homogeneously surrounding and wetting the dendrites of the solid phase, causing grains to detach from each other and producing the intended solid globules immersed in liquid.

  14. A new imidazolium-embedded C{sub 18} stationary phase with enhanced performance in reversed-phase liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Hongdeng [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Mallik, Abul K. [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Takafuji, Makoto [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), Kumamoto 862-0901 (Japan); Liu Xia; Jiang Shengxiang [Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Ihara, Hirotaka, E-mail: ihara@kumamoto-u.ac.jp [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), Kumamoto 862-0901 (Japan)

    2012-08-13

    Highlights: Black-Right-Pointing-Pointer Imidazolium-embedded C{sub 18} stationary phase was prepared and characterized. Black-Right-Pointing-Pointer Enhanced chromatographic selectivity was observed in SiImC{sub 18} column. Black-Right-Pointing-Pointer Seven nucleosides and bases were separated using only water as eluent within 8 min. Black-Right-Pointing-Pointer Multiple-interactions induced by embedded polar imidazolium was investigated. - Abstract: In this paper, a new imidazolium-embedded C{sub 18} stationary phase (SiImC{sub 18}) for reversed-phase high-performance liquid chromatography is described. 1-Allyl-3-octadecylimidazolium bromide ionic liquid compound having a long alkyl chain and reactive groups was newly prepared and grafted onto 3-mercaptopropyltrimethoxysilane-modified silica via a surface-initiated radical-chain transfer addition reaction. The SiImC{sub 18} obtained was characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, diffuse reflectance infrared Fourier transform, and solid-state {sup 13}C and {sup 29}Si cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy. The selectivity toward polycyclic aromatic hydrocarbons relative to that toward alkylbenzenes exhibited by SiImC{sub 18} was higher than the corresponding selectivity exhibited by a conventional octadecyl silica (ODS) column, which could be explained by electrostatic {pi}-{pi} interaction cationic imidazolium and electron-rich aromatic rings. On the other hand, SiImC{sub 18} also showed high selectivity for polar compounds, which was based on the multiple interaction and retention mechanisms of this phase with different analytes. 1,6-Dinitropyrene and 1,8-dinitropyrene, which form a positional isomer pair of dipolar compounds, were separated successfully with the SiImC{sub 18} phase. Seven nucleosides and bases (i.e. cytidine, uracil, uridine, thymine, guanosine, xanthosine, and adenosine) were separated using only water as

  15. Investigating the solid-liquid phase transition of water nanofilms using the generalized replica exchange method

    Science.gov (United States)

    Lu, Qing; Kim, Jaegil; Farrell, James D.; Wales, David J.; Straub, John E.

    2014-11-01

    The generalized Replica Exchange Method (gREM) was applied to study a solid-liquid phase transition in a nanoconfined bilayer water system using the monatomic water (mW) model. Exploiting optimally designed non-Boltzmann sampling weights with replica exchanges, gREM enables an effective sampling of configurations that are metastable or unstable in the canonical ensemble via successive unimodal energy distributions across phase transition regions, often characterized by S-loop or backbending in the statistical temperature. Extensive gREM simulations combined with Statistical Temperature Weighted Histogram Analysis Method (ST-WHAM) for nanoconfined mW water at various densities provide a comprehensive characterization of diverse thermodynamic and structural properties intrinsic to phase transitions. Graph representation of minimized structures of bilayer water systems determined by the basin-hopping global optimization revealed heterogeneous ice structures composed of pentagons, hexagons, and heptagons, consistent with an increasingly ordered solid phase with decreasing density. Apparent crossover from a first-order solid-liquid transition to a continuous one in nanoconfined mW water with increasing density of the system was observed in terms of a diminishing S-loop in the statistical temperature, smooth variation of internal energies and heat capacities, and a characteristic variation of lateral radial distribution functions, and transverse density profiles across transition regions.

  16. Collagen films with stabilized liquid crystalline phases and concerns on osteoblast behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Minjian; Ding, Shan; Min, Xiang; Jiao, Yanpeng, E-mail: tjiaoyp@jnu.edu.cn; Li, Lihua; Li, Hong; Zhou, Changren, E-mail: tcrz9@jnu.edu.cn

    2016-01-01

    To duplicate collagen's in vivo liquid crystalline (LC) phase and investigate the relationship between the morphology of LC collagen and osteoblast behavior, a self-assembly method was introduced for preparing collagen films with a stabilized LC phase. The LC texture and topological structure of the films before and after stabilization were observed with polarizing optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The relationship between the collagen films and osteoblast behavior was studied with the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide method, proliferation index detection, alkaline phosphatase measurements, osteocalcin assay, inverted microscopy, SEM observation, AFM observation, and cytoskeleton fluorescence staining. The results showed that the LC collagen film had continuously twisting orientations in the cholesteric phase with a typical series of arced patterns. The collagen fibers assembled in a well-organized orientation in the LC film. Compared to the non-LC film, the LC collagen film can promote cell proliferation, and increase ALP and osteocalcin expression, revealing a contact guide effect on osteoblasts. - Highlights: • Collagen film with liquid crystalline (LC) phase was observed by POM, SEM and AFM. • The effect of LC collagen film on osteoblasts behaviors was studied in detail. • LC collagen film promoted osteoblast proliferation and osteogenesis activity.

  17. Bacteria and fungi inactivation by photocatalysis under UVA irradiation: liquid and gas phase.

    Science.gov (United States)

    Rodrigues-Silva, Caio; Miranda, Sandra M; Lopes, Filipe V S; Silva, Mário; Dezotti, Márcia; Silva, Adrián M T; Faria, Joaquim L; Boaventura, Rui A R; Vilar, Vítor J P; Pinto, Eugénia

    2017-03-01

    In the last decade, environmental risks associated with wastewater treatment plants (WWTPs) have become a concern in the scientific community due to the absence of specific legislation governing the occupational exposure limits (OEL) for microorganisms present in indoor air. Thus, it is necessary to develop techniques to effectively inactivate microorganisms present in the air of WWTPs facilities. In the present work, ultraviolet light A radiation was used as inactivation tool. The microbial population was not visibly reduced in the bioaerosol by ultraviolet light A (UVA) photolysis. The UVA photocatalytic process for the inactivation of microorganisms (bacteria and fungi, ATCC strains and isolates from indoor air samples of a WWTP) using titanium dioxide (TiO 2 P25) and zinc oxide (ZnO) was tested in both liquid-phase and airborne conditions. In the slurry conditions at liquid phase, P25 showed a better performance in inactivation. For this reason, gas-phase assays were performed in a tubular photoreactor packed with cellulose acetate monolithic structures coated with P25. The survival rate of microorganisms under study decreased with the catalyst load and the UVA exposure time. Inactivation of fungi was slower than resistant bacteria, followed by Gram-positive bacteria and Gram-negative bacteria. Graphical abstract Inactivation of fungi and bacteria in gas phase by photocatalitic process performed in a tubular photoreactor packed with cellulose acetate monolith structures coated with TiO 2 .

  18. Reversed-phase high-performance liquid chromatography of tenuazonic acid and related tetramic acids.

    Science.gov (United States)

    Shephard, G S; Thiel, P G; Sydenham, E W; Vleggaar, R; Marasas, W F

    1991-05-03

    A reversed-phase high-performance liquid chromatographic system for the determination of the fungal toxin, tenuazonic acid, (5S,8S)-3-acetyl-5-sec.-butyltetramic acid, is described. The system utilizes a column packed with deactivated end-capped C18 silica with a high carbon load to overcome the problem of poor chromatographic performance of this beta-diketone on reversed-phase liquid chromatography which previously necessitated the use of anion-exchange, ligand-exchange or ion-pairing methods. The reversed-phase system allows the separation of tenuazonic acid from its (5R,8S)-diastereomer, allo-tenuazonic acid and was applied to the detection of tenuazonic acid in cultures of Alternaria alternata and Phoma sorghina. By means of diode-array ultraviolet detection, (5S)-3-acetyl-5-isopropyltetramic acid was observed in extracts of culture material. This metabolite was purified using the analytical reversed-phase system and was identified by 1H and 13C nuclear magnetic resonance spectroscopy.

  19. Lapatinib versus hormone therapy in patients with advanced renal cell carcinoma: a randomized phase III clinical trial

    DEFF Research Database (Denmark)

    Ravaud, Alain; Hawkins, Robert; Gardner, Jason P

    2008-01-01

    of metastatic sites--were randomly assigned to lapatinib 1,250 mg daily or HT. The primary end point was time to progression (TTP); secondary end points included overall survival (OS), safety, and biomarker analyses. RESULTS: Four hundred sixteen patients were enrolled onto the study. Median TTP was 15.3 weeks......PURPOSE: Lapatinib is an orally reversible inhibitor of epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER-2) tyrosine kinases with demonstrated activity in patients with HER-2-positive breast cancer. In the current phase III open-label trial, lapatinib...... was compared with hormone therapy (HT) in patients with advanced renal cell carcinoma (RCC) that express EGFR and/or HER-2. PATIENTS AND METHODS: Patients with advanced RCC who had experienced disease progression through first-line cytokine therapy--stratified by Karnofsky performance status and number...

  20. The application of axisymmetric lattice Boltzmann two-phase model on simulations of liquid film dewetting

    Science.gov (United States)

    Wang, Lei; Sun, Jianglong

    2017-08-01

    An axisymmetric two-phase lattice Boltzmann method is applied to simulate the dewetting dynamics of a thin liquid film on a substrate. Initially, a circular dry spot exists in the center of the liquid film. A contact line forms around the dry spot and expands outwards. The liquid films dewetting on smooth and rough substrates are investigated. For a smooth substrate, the effects of the contact angle (θeq), Ohnesorge number (Oh), and viscosity ratio (λμ) are studied. It is observed that the contact line recedes with a constant velocity V and that if θeq > 45°, V has a linear relationship with θeq, which has never been mentioned in previous literatures. For a rough substrate, well-distributed pillars are set up to represent the roughness. There are two states for the liquid film dewetting on a rough substrate: Cassie and Wenzel states. By comparison, it is found that the speed of the liquid film dewetting on the rough substrate of the Cassie state is slightly faster than that on the smooth substrate but much faster than that on the rough substrate of the Wenzel state, i.e., Wenzel state can obviously hold back the movement of the receding contact line. The corresponding mechanism is analyzed. The effect of the geometric factors of the pillars on the dewetting speed is discussed in detail. It is indicated that both the width and the depth of the grooves in roughness can significantly affect the dewetting speed. The results are helpful to design structured substrates for controlling the dewetting process of the liquid film.

  1. Combination of dispersive liquid-liquid microextraction and solid-phase microextraction: An efficient hyphenated sample preparation method.

    Science.gov (United States)

    Jafari, Mohammad T; Saraji, Mohammad; Mossaddegh, Mehdi

    2016-09-30

    Two well-known microextraction methods, dispersive liquid-liquid microextraction (DLLME) and solid-phase microextraction (SPME), were combined, resulting in as an encouraging method. The method, named DLLME-SPME, was performed based on total vaporization technique. For the DLLME step, 1,1,2,2-tetrachloroethane and acetonitrile were used as extraction and disperser solvents, respectively. Halloysite nanotubes-titanium dioxide was used as the fiber coating in the SPME step. The method was applied for the extraction of diazinon and parathion (as the test compounds) in environmental water samples and fruit juices, and gas chromatography-corona discharge ion mobility spectrometry was used as the determination apparatus. Desorption temperature and time, extraction temperature and time, and the volume of the extracting solvent in the DLLME step were optimized as the effective parameters on the extraction efficiency. The relative standard deviations (RSDs) of intra-day were found to be 4-7% and 6-8% for diazinon and parathion, respectively. Also, the RSDs of inter-day were 7-9% and 8-10% for diazinon and parathion, respectively. The limits of quantification and detection were obtained to be 0.015 and 0.005μgL(-1) for diazinon, and 0.020 and 0.007μgL(-1) for parathion. A good linearity range (r(2)˃0.993) was obtained in the range of 0.015-3.000 and 0.020-3.000μgL(-1) for diazinon and parathion, respectively. The high enrichment factors were obtained as 3150 and 2965 for diazinon and parathion, respectively. This method showed high sensitivity with good recovery values (between 87 and 99%) for the extraction of target analytes in the real samples. Overall, the results revealed that the developed DLLME-SPME method had better extraction efficiency than DLLME and SPME alone. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Commissioning and Charge Readout Calibration of a 5 Ton Dual Phase Liquid Argon TPC

    CERN Document Server

    AUTHOR|(CDS)2098555

    Dual phase time projection chambers with amplification of ionization electrons provide a novel technique for measuring and analyzing rare events with excellent spatial resolution and great calorimetric properties. This thesis describes the commissioning of the WA105 3 x 1 x 1 m3 dual phase liquid argon detector, built to demonstrate the performance of this kind of detector on large scales in order to determine the viability of giant dual phase time projection chambers in long baseline neutrino oscillation experiments. The properties of the insulation and the main tank vessel are described and analyzed, such as the pressure, temperature and argon purity requirements during operation in order to guarantee stable conditions and good event tracking. As signals are induced due to electrons from ionizing radiation, crosstalk is caused by capacitive couplings between strips of the charge readout plane and in the electronics of the data acquisition. These induced signals are studied and compared to capacitance and pu...

  3. Small interfering ribonucleic acid induces liquid-to-ripple phase transformation in a phospholipid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, Amit; Nomura, Ken-ichi; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States)

    2014-09-15

    Small interfering ribonucleic acid (siRNA) molecules play a pivotal role in silencing gene expression via the RNA interference mechanism. A key limitation to the widespread implementation of siRNA therapeutics is the difficulty of delivering siRNA-based drugs to cells. Here, we examine changes in the structure and dynamics of a dipalmitoylphosphatidylcholine bilayer in the presence of a siRNA molecule and mechanical barriers to siRNA transfection in the bilayer. Our all-atom molecular dynamics simulation shows that siRNA induces a liquid crystalline-to-ripple phase transformation in the bilayer. The ripple phase consists of a major region of non-interdigitated and a minor region of interdigitated lipid molecules with an intervening kink. In the ripple phase, hydrocarbon chains of lipid molecules have large compressive stresses, which present a considerable barrier to siRNA transfection.

  4. Transient state study of electric motor heating and phase change solid-liquid cooling

    Energy Technology Data Exchange (ETDEWEB)

    Bellettre, J.; Sartre, V.; Lallemand, A. [Centre National de la Recherche Scientifique (CNRS), Centre de Thermique de Lyon, Villeurbanne, 69 (France); Biais, F. [AUXILEC, Chatou, 78 (France)

    1997-01-01

    This study reports on modelling of an autosynchronous electric motor stator, operating at transient state. The developed model, of the modal type, includes around 20 nodes. The simulations showed that hot spots are localized on the winding heads and led to the choice of a solid-liquid phase change cooling system. The comparison between simulation and experiment permitted the identification of unknown parameters. The model gives a good accuracy during steady-state and in the rising temperature phase. The modelling of the phase change cooling is realized by the addition of two nodes. The sensitivity analysis to PCM properties shows that the hot spot temperature decreases with increasing conductivities, inertia and latent heat of melting of the PCM and with decreasing melting temperature. Gallium (metal melting at 30{sup o}C) is the best PCM for the cooling of hot spots and P116 paraffin is the best non-metallic PCM. (author)

  5. [Separation of enantiomeric labetalol by reversed-phase high performance liquid chromatography].

    Science.gov (United States)

    Zhao, H; Li, H; Qui, Z

    1999-07-01

    A reversed-phase high performance liquid chromatographic method for the separation of labetalol enantiomers was developed. In the method, 2, 3, 4, 6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC) was chosen as the reagent for pre-column chiral derivatization of labetalol to give four diastereomeric thiourea derivatives. These derivatives were efficiently separated on a Nova-Pak C18 column using V(MeOH):V(0.01 mol.L-1(pH 7.00) H2PO4(-)-HPO(4)2- buffer) = 51:49 as the mobile phase and detected by UV detector at a wavelength of 250 nm or fluorescence detector at lambda ex = 340 nm and lambda em = 440 nm. The effects of the pH of mobile phase on the retention and fluorescence absorbance are also discussed.

  6. Vapor-Phase Free Radical Polymerization in the Presence of Ionic Liquids

    Science.gov (United States)

    Gupta, Malancha

    2011-03-01

    Ionic liquids (ILs) have recently attracted significant interest as an environmentally-friendly alternative to traditional volatile organic solvents because ILs are non-volatile, non-flammable, and can be easily recycled. ILs can be exploited in many ways to improve the selectivity and kinetics of chemical reactions, including polymer synthesis. Ionic liquids have negligible vapor pressure and are therefore stable under vacuum. A few studies have investigated ILs as substrates in inorganic vacuum deposition processes, but to our knowledge ILs have not been used in vapor phase polymerization systems. We have recently introduced ionic liquids into the initiated chemical vapor deposition (iCVD) process for the first time. The iCVD polymerization process occurs via a free-radical mechanism, and the deposited polymeric films are compositionally analogous to solution-phase polymers. Despite the wide range of polymers that have been synthesized using iCVD, it has proven difficult to polymerize monomers with low surface concentrations such as styrene and low propagation rates such as methyl methacrylate and it is difficult to produce block copolymers. In this talk, we will show that our novel ILiCVD system can address some of these shortcomings. We will explain the effects of deposition time, temperature, and monomer solubility on the morphology of the polymer and the molecular weight of the polymer chains.

  7. Theoretical model and experimental verification on the PID tracking method using liquid crystal optical phased array

    Science.gov (United States)

    Wang, Xiangru; Xu, Jianhua; Huang, Ziqiang; Wu, Liang; Zhang, Tianyi; Wu, Shuanghong; Qiu, Qi

    2017-02-01

    Liquid crystal optical phased array (LC-OPA) has been considered with great potential on the non-mechanical laser deflector because it is fabricated using photolithographic patterning technology which has been well advanced by the electronics and display industry. As a vital application of LC-OPA, free space laser communication has demonstrated its merits on communication bandwidth. Before data communication, ATP (acquisition, tracking and pointing) process costs relatively long time to result in a bottle-neck of free space laser communication. Meanwhile, dynamic real time accurate tracking is sensitive to keep a stable communication link. The electro-optic medium liquid crystal with low driving voltage can be used as the laser beam deflector. This paper presents a fast-track method using liquid crystal optical phased array as the beam deflector, CCD as a beacon light detector. PID (Proportion Integration Differentiation) loop algorithm is introduced as the controlling algorithm to generate the corresponding steering angle. To achieve the goal of fast and accurate tracking, theoretical analysis and experimental verification are demonstrated that PID closed-loop system can suppress the attitude random vibration. Meanwhile, theoretical analysis shows that tracking accuracy can be less than 6.5μrad, with a relative agreement with experimental results which is obtained after 10 adjustments that the tracking accuracy is less than12.6μrad.

  8. Hydrodynamic models of gas-liquid two-phase flow in porous media

    Directory of Open Access Journals (Sweden)

    B GutiérrezR

    2016-09-01

    Full Text Available Equations and models describing the hydrodynamic of gas-liquid two-phase flows in porous media have become increasingly necessary in order to predict their main features throughout porous networks. The main subject of this research was to study the influence of capillary, viscous and inertial forces and flow configurations on the hydrodynamic features of a gas-liquid two-phase flow in a glass micromodel. Experimental results were obtained and compared with those predicted by three published models. The Fundamental Forces Balance and the Fluid-Fluid Interface models did not describe accurately experimental behavior even when the first of them considers particular characteristics of flow patterns. Semi-empirical models such as The Relative Permeability can describe physical flow characteristics and can also be modified to include different effects not initially considered. Traditionally, relative permeabilities have been associated almost exclusively with saturation conditions. However, it was concluded in this research that liquid relative permeability is function of saturation conditions but also depends on flow patterns and Capillary number.

  9. The Promotion of Liquid Phase Sintering of Boron-Containing Powder Metallurgy Steels by Adding Nickel

    Directory of Open Access Journals (Sweden)

    Wu Ming-Wei

    2015-01-01

    Full Text Available Boron is a feasible alloying element for liquid phase sintering (LPS of powder metallurgy (PM steels. This study investigated the effect of nickel (Ni, which is widely used in PM steels, on the liquid phase sintering of boron-containing PM steels. The results showed that the addition of 1.8wt% Ni does not apparently modify the LPS mechanism of boron-containing PM steels. However, adding 1.8wt% Ni slightly improves the LPS densification from 0.60 g/cm3 to 0.65 g/cm3, though the green density is reduced. Thermodynamic simulation demonstrated that the presence of Ni lowers the temperature region of liquid formation, resulting in enhanced LPS densification. Moreover, original graphite powders remains in the steels sintered at 1200 ºC. These graphite powders mostly dissolve into the base iron powder when the sintering temperature is increased from 1200 ºC to 1250 ºC.

  10. Design and implementation of an automated liquid-phase microextraction-chip system coupled on-line with high performance liquid chromatography

    DEFF Research Database (Denmark)

    Li, Bin; Petersen, Nickolaj J.; Payán, María D Ramos

    2014-01-01

    An automated liquid-phase microextraction (LPME) device in a chip format has been developed and coupled directly to high performance liquid chromatography (HPLC). A 10-port 2-position switching valve was used to hyphenate the LPME-chip with the HPLC autosampler, and to collect the extracted....... The composition of the supported liquid membrane (SLM) and carrier was optimized in order to achieve reasonable extraction performance of all the five alkaloids. With 1-octanol as SLM solvent and with 25mM sodium octanoate as anionic carrier, extraction recoveries for the different opium alkaloids ranged between....... The repeatability was within 5.0-10.8% (RSD). The membrane liquid in the LPME-chip was regenerated automatically between every third injection. With this procedure the liquid membrane in the LPME-chip was stable in 3-7 days depending on the complexity of sample solutions with continuous operation. With this LPME...

  11. Catalytic decomposition of carbon-based liquid-phase chemical hydrogen storage materials for hydrogen generation under mild conditions

    National Research Council Canada - National Science Library

    Sánchez, Felipe; Motta, Davide; Dimitratos, Nikolaos

    2016-01-01

    ... investment, and low potential risks. In this review, we survey the progress made in hydrogen generation from carbon-based liquid-phase chemical hydrogen storage materials, focusing mainly on the catalytic decomposition of formic acid...

  12. Influence of liquid crystalline phases on the tunability of a random laser

    Science.gov (United States)

    Trull, José; Salud, Josep; Diez-Berart, Sergio; López, David O.

    2017-05-01

    In this paper, we report the temperature behavior of an optimized disordered photonic system-based liquid crystal by means of heat capacity and refractive index measurements. The scattering system is formed by a porous borosilicate glass random matrix (about 60%) infiltrated with a smectogenic liquid crystal (about 16%) and a small amount of laser dye (0.1%). The rest of the scattering system is about 24% air, giving rise to a high refractive index contrast scattering system. Such a system has the functionality to change the refractive index contrast with temperature due to the liquid crystal temperature behavior. The system, optically pumped by the second harmonic of a Q -switched Nd:YAG pulsed laser working at 532 nm, exhibits random laser action, the threshold of which depends upon the liquid crystalline mesophase. Temperatures of existence of the smectic-B phase correspond to the most optimized random laser. In such a mesophase, the transport mean free path has been determined as about 16 μm in a coherent backscattering experiment.

  13. Optimization of oxygen mass transfer in a multiphase bioreactor with perfluorodecalin as a second liquid phase.

    Science.gov (United States)

    Amaral, Priscilla F F; Freire, Mara G; Rocha-Leão, Maria Helena M; Marrucho, Isabel M; Coutinho, João A P; Coelho, Maria Alice Z

    2008-02-15

    Oxygenation is an important parameter involved in the design and operation of mixing-sparging bioreactors and it can be analyzed by means of the oxygen mass transfer coefficient (k(L)a). The operational conditions of a stirred, submerged aerated 2-L bioreactor have been optimized by studying the influence of a second liquid phase with higher oxygen affinity (perfluorodecalin or olive oil) in the k(L)a. Using k(L)a measurements, the influence of the following parameters on the oxygen transfer rate was evaluated: the volume of working medium, the type of impellers and their position, the organic phase concentration, the aqueous phase composition, and the concentration of inactive biomass. This study shows that the best experimental conditions were achieved with a perfluorodecalin volume fraction of 0.20, mixing using two Rushton turbines with six vertical blades and in the presence of YPD medium as the aqueous phase, with a k(L)a value of 64.6 h(-1). The addition of 20% of perfluorodecalin in these conditions provided a k(L)a enhancement of 25% when pure water was the aqueous phase and a 230% enhancement when YPD medium was used in comparison to their respective controls (no perfluorodecalin). Furthermore it is shown that the presence of olive oil as a second liquid phase is not beneficial to the oxygen transfer rate enhancement, leading to a decrease in the k(L)a values for all the concentrations studied. It was also observed that the magnitude of the enhancement of the k(L)a values by perfluorodecalin depends on the biomass concentration present. (c) 2007 Wiley Periodicals, Inc.

  14. Trace analysis of selected hormones and sterols in river sediments by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Matić, Ivana; Grujić, Svetlana; Jauković, Zorica; Laušević, Mila

    2014-10-17

    In this paper, development and optimization of new LC-MS method for determination of twenty selected hormones, human/animal and plant sterols in river sediments were described. Sediment samples were prepared using ultrasonic extraction and clean up with silica gel/anhydrous sodium sulphate cartridge. Extracts were analyzed by liquid chromatography-linear ion trap-tandem mass spectrometry, with atmospheric pressure chemical ionization. The optimized extraction parameters were extraction solvent (methanol), weight of the sediment (2 g) and time of ultrasonic extraction (3× 10 min). Successful chromatographic separation of hormones (estriol and estrone, 17α- and 17β-estradiol) and four human/animal sterols (epicoprostanol, coprostanol, α-cholestanol and β-cholestanol) that have identical fragmentation reactions was achieved. The developed and optimized method provided high recoveries (73-118%), low limits of detection (0.8-18 ng g(-1)) and quantification (2.5-60 ng g(-1)) with the RSDs generally lower than 20%. Applicability of the developed method was confirmed by analysis of six river sediment samples. A widespread occurrence of human/animal and plant sterols was found. The only detected hormone was mestranol in just one sediment sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Gradient elution in aqueous normal-phase liquid chromatography on hydrosilated silica-based stationary phases.

    Science.gov (United States)

    Soukup, Jan; Janás, Petr; Jandera, Pavel

    2013-04-19

    The possibility of applying a theoretical model in the prediction of the retention of phenolic acids on hydrosilated silica, in aqueous normal phase mode was studied. The actual gradient of the aqueous component in acetonitrile may fluctuate from the pre-set program, as even the gradient-grade acetonitrile contains some water. Hence, the actual concentration of water during the gradient run is higher than pre-set by the gradient program, which leads to lower than expected sample retention. Furthermore, the actual gradient profile may be affected by an increase in water uptake on a polar column during the gradient run. These effects were investigated using the using frontal analysis method and Karl-Fischer titration, for the determination of water in the initial mobile phase, and in the column effluent. Preferential adsorption of water on the Silica hydride, Diamond hydride, UDC Cholesterol, Bidentate C18, and Phenyl hydride columns can be described by Langmuir isotherms. At the column saturation capacity, less than one monomolecular water layer is adsorbed, with a further decrease in coverage density for modified materials. Parameters of semi-logarithmic and logarithmic model equations, describing the dependence of retention factor on the concentration of water, were determined under isocratic conditions. These parameters and linear gradient profiles corrected for the actual water concentrations were used in calculation of gradient retention data. The corrections for the actual water concentration greatly improved the agreement between the experiment and the predicted gradient elution volumes. Generally, the semi-logarithmic model provides slightly better prediction of the gradient data, with respect to the logarithmic retention model. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Determination of four sulfonylurea herbicides in tea by matrix solid-phase dispersion cleanup followed by dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Liang, Pei; Wang, Jinjin; Liu, Guojiao; Guan, Jinyan

    2014-09-01

    Matrix solid-phase dispersion combined with dispersive liquid-liquid microextraction has been developed as a new sample pretreatment method for the determination of four sulfonylurea herbicides (chlorsulfuron, bensulfuron-methyl, chlorimuron-ethyl, and pyrazosulfuron) in tea by high-performance liquid chromatography with diode array detection. The extraction and cleanup by matrix solid-phase dispersion was carried out by using CN-silica as dispersant and carbon nanotubes as cleanup sorbent eluted with acidified dichloromethane. The eluent of matrix solid-phase dispersion was evaporated and redissolved in 0.5 mL methanol, and used as the dispersive solvent of the following dispersive liquid-liquid microextraction procedure for further purification and enrichment of the target analytes before high-performance liquid chromatography analysis. Under the optimum conditions, the method yielded a linear calibration curve in the concentration range from 5.0 to 10 000 ng/g for target analytes with a correlation coefficients (r(2)) ranging from 0.9959 to 0.9998. The limits of detection for the analytes were in the range of 1.31-2.81 ng/g. Recoveries of the four sulfonylurea herbicides at two fortification levels were between 72.8 and 110.6% with relative standard deviations lower than 6.95%. The method was successfully applied to the analysis of four sulfonylurea herbicides in several tea samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Mobile phase effects on the retention on polar columns with special attention to the dual hydrophilic interaction - reversed-phase liquid chromatography mechanism: A review.

    Science.gov (United States)

    Jandera, Pavel; Hájek, Tomáš

    2017-10-26

    Hydrophilic interaction liquid chromatography on polar columns in aqueous-organic mobile phases has become increasingly popular for the separation of many biologically important compounds in chemical, environmental, food, toxicological and other samples. In spite of many new applications appearing in literature, the retention mechanism is still controversial. This review addresses recent progress in understanding of the retention models in hydrophilic interaction liquid chromatography. The main attention is focused on the role of water, both adsorbed by the column and contained in the bulk mobile phase. Further, the theoretical retention models in the isocratic and gradient elution modes are discussed. The dual hydrophilic interaction liquid chromatography reversed-phase retention mechanism on polar columns is treated in detail, especially with respect to the practical use in one- and two-dimensional liquid chromatography separations. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Phase behavior and properties of the liquid-crystal dimer 1'',7''-bis(4-cyanobiphenyl-4'-yl) heptane: a twist-bend nematic liquid crystal.

    Science.gov (United States)

    Cestari, M; Diez-Berart, S; Dunmur, D A; Ferrarini, A; de la Fuente, M R; Jackson, D J B; Lopez, D O; Luckhurst, G R; Perez-Jubindo, M A; Richardson, R M; Salud, J; Timimi, B A; Zimmermann, H

    2011-09-01

    The liquid-crystal dimer 1'',7''-bis(4-cyanobiphenyl-4'-yl)heptane (CB7CB) exhibits two liquid-crystalline mesophases on cooling from the isotropic phase. The high-temperature phase is nematic; the identification and characterization of the other liquid-crystal phase is reported in this paper. It is concluded that the low-temperature mesophase of CB7CB is a new type of uniaxial nematic phase having a nonuniform director distribution composed of twist-bend deformations. The techniques of small-angle x-ray scattering, modulated differential scanning calorimetry, and dielectric spectroscopy have been applied to establish the nature of the nematic-nematic phase transition and the structural features of the twist-bend nematic phase. In addition, magnetic resonance studies (electron-spin resonance and (2)H nuclear magnetic resonance) have been used to investigate the orientational order and director distribution in the liquid-crystalline phases of CB7CB. The synthesis of a specifically deuterated sample of CB7CB is reported, and measurements showed a bifurcation of the quadrupolar splitting on entering the low-temperature mesophase from the high-temperature nematic phase. This splitting could be interpreted in terms of the chirality of the twist-bend structure of the director. Calculations using an atomistic model and the surface interaction potential with Monte Carlo sampling have been carried out to determine the conformational distribution and predict dielectric and elastic properties in the nematic phase. The former are in agreement with experimental measurements, while the latter are consistent with the formation of a twist-bend nematic phase.

  19. Confinement effects on lyotropic nematic liquid crystal phases of graphene oxide dispersions

    Science.gov (United States)

    Al-Zangana, Shakhawan; Iliut, Maria; Turner, Michael; Vijayaraghavan, Aravind; Dierking, Ingo

    2017-12-01

    Graphene oxide (GO) forms well ordered liquid crystal (LC) phases in polar solvents. Here, we map the lyotropic phase diagram of GO as a function of the lateral dimensions of the GO flakes, their concentration, geometrical confinement configuration and solvent polarity. GO flakes were prepared in water and transferred into other polar solvents. Polarising optical microscopy (POM) was used to determine the phase evolution through the isotropic-biphasic-nematic transitions of the GO LC. We report that the confinement volume and geometry relative to the particle size is critical for the observation of the lyotropic phase, specifically, this determines the low-end concentration limit for the detection of the GO LC. Additionally, a solvent with higher polarisability stabilises the LC phases at lower concentrations and smaller flake sizes. GO LCs have been proposed for a range of applications from display technologies to conductive fibres, and the behaviour of LC phase formation under confinement imposes a limit on miniaturisation of the dimensions of such GO LC systems which could significantly impact on their potential applications.

  20. Design and simulation of single-electrode liquid crystal phased arrays

    Science.gov (United States)

    Bellini, B.; Geday, M. A.; Bennis, N.; Spadło, A.; Quintana, X.; Otón, J. M.; Dąbrowski, R.

    2006-12-01

    Liquid crystal (LC) phased arrays and gratings have been employed in optical switching and routing [1]. These diffractive optic elements are of great interest because they can be scaled up to a large number of elements and their optical properties can be electrically addressed with a low driving voltage. LC phase gratings have been achieved either by periodic addressing of pixels or by using periodically-modified structures. The latter approach leads to less reconfigurable devices but the addressing is simpler. In this paper we focus on optical phased arrays where the phase is varied either continuously or discretely and where the periodicity is induced by electrode configuration. We first describe a possible structure based on a conductive silicon wafer. We argue that this structure can induce either continuously or discretely varying arrays while applying single voltage to the array. In the second part we simulate the behaviour of such arrays. We base the simulation on a LC synthesized at the Military University of Technology, this high-birefringence nematic LC shows in a 4-μm thick cell a linear phase shift range of more than 360° between 1.2 V and 1.8 V. We calculate the distribution of the LC molecule director and assess the performance of the array with respect to the applied voltage. Finally, the relevance of such technology for switchable phased arrays is discussed.

  1. Phase biaxiality in nematic liquid crystalline side-chain polymers of various chemical constitutions.

    Science.gov (United States)

    Severing, Kirsten; Stibal-Fischer, Elke; Hasenhindl, Alfred; Finkelmann, Heino; Saalwächter, Kay

    2006-08-17

    In a previous deuterium NMR study conducted on a liquid crystalline (LC) polymer with laterally attached book-shaped molecules as the mesogenic moiety, we have revealed a biaxial nematic phase below the conventional uniaxial nematic phase (Phys. Rev. Lett. 2004, 92, 125501). To elucidate details of its formation, we here report on deuterium NMR experiments that have been conducted on different types of LC side-chain polymers as well as on mixtures with low-molar-mass mesogens. Different parameters that affect the formation of a biaxial nematic phase, such as the geometry of the attachment, the spacer length between the polymer backbone and the mesogenic unit, as well as the polymer dynamics, were investigated. Surprisingly, also polymers with terminally attached mesogens (end-on polymers) are capable of forming biaxial nematic phases if the flexible spacer is short and thus retains a coupling between the polymer backbone and the LC phase. Furthermore, the most important parameter for the formation of a biaxial nematic phase is the dynamics of the polymer backbone, as the addition of a small percentage of low molar mass LC to the biaxial nematic polymer from the original study served to shift both the glass transition and the appearance of detectable biaxiality in a very similar fashion. Plotting different parameters for the investigated systems as a function of T/Tg also reveals the crucial role of the dynamics of the polymer backbone and hence the glass transition.

  2. Optimization of solid phase microextraction coatings for liquid chromatography mass spectrometry determination of neurotransmitters.

    Science.gov (United States)

    Cudjoe, Erasmus; Pawliszyn, Janusz

    2014-05-09

    A simple solid phase microextraction method coupled to liquid chromatography mass spectrometry is introduced for the analysis of neurotransmitter compounds with a wide range of polarities in biological matrices. A novel "reversed" reverse-phase chromatographic method was developed without pre-column derivatization for the analysis of dopamine, serotonin, gamma aminobutyric acid and glutamate. New solid phase microextraction "in house" coatings using mixed-mode solid phase extraction particles were prepared, and used for the extraction of polar neurotransmitters. The polymer-support base reverse phase mixed-mode sorbents with strong ion exchange properties generally had higher extraction efficiencies compared to similar sorbents with weak ion exchange properties. The linear range was determined to be between 0.01 and 150ng/mL for all the analytes, except for GABA, which was from 0.1 to 100ng/mL. The limit of detection range was from 6 to 10pg/mL for all the neurotransmitters, and the limits of quantitation were in the range of 20-35pg/mL. The results demonstrate the potential of the SPME-LC-MS/MS technique for bioanalysis of small polar endogenous compounds, such as neurotransmitters, from various biological matrices using the mixed-mode sorbents as the extraction phase. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Effect of mobile phase composition on the retention of selected alkaloids in reversed-phase liquid chromatography with chaotropic salts.

    Science.gov (United States)

    Flieger, J

    2007-12-21

    Sodium hexafluorophosphate, perchlorate and trifluoroacetate were applied as ion-ion interaction reagents in reversed-phase liquid chromatography. The separation of chosen alkaloids was performed by changing the kind of the organic modifier (methanol, acetonitrile, tetrahydrofuran), concentration of the ion-ion-interaction reagents and the concentration of phosphate buffer at constant pH (2.7) in the mobile phase. Obtained results were analyzed in connection to a dynamic ion-exchange model of retention and ion-ion interaction effects. The perturbation method was applied to test proposed retention theories. The formation of ion-complexes controlling the retention in chaotropic systems was confirmed. On the basis of the relationships of capacity factors (k) versus salt concentrations derived experimentally, absolute increases in capacity factors, the desolvation parameters and the limiting retention factors were calculated and compared for all the investigated compounds in eluent systems studied. The selectivity of the proposed mobile phases was compared on the basis of the separation of alkaloid mixture.

  4. Liquid Phase Methanol LaPorte Process Development Unit: Modification, operation, and support studies

    Energy Technology Data Exchange (ETDEWEB)

    1990-08-31

    A gas phase and a slurry phase radioactive tracer study was performed on the 12 ton/day Liquid Phase Methanol (LPMEOH) Process Development Unit (PDU) in LaPorte, Texas. To study the gas phase mixing characteristics, a radioactive argon tracer was injected into the feed gas and residence time distribution was generated by measuring the response at the reactor outlet. Radioactive manganese oxide powder was independently injected into the reactor to measure the slurry phase mixing characteristics. A tanks-in-series model and an axial dispersion model were applied to the data to characterize the mixing in the reactor. From the axial dispersion model, a translation to the number of CSTR's (continuous stirred tank reactors) was made for comparison purposes with the first analysis. Dispersion correlations currently available in the literature were also compared. The tanks-in-series analysis is a simpler model whose results are easily interpreted. However, it does have a few drawbacks; among them, the lack of a reliable method for scaleup of a reactor and no direct correlation between mixing in the slurry and gas phases. The dispersion model allows the mixing in the gas and slurry phases to be characterized separately while including the effects of phase transfer. This analysis offers a means for combining the gas and slurry phase dispersion models into an effective dispersion coefficient, which, in turn, can be related to an equivalent number of tanks-in-series. The dispersion methods reported are recommended for scaleup of a reactor system. 24 refs., 18 figs., 8 tabs.

  5. All-soft, battery-free, and wireless chemical sensing platform based on liquid metal for liquid- and gas-phase VOC detection.

    Science.gov (United States)

    Kim, Min-Gu; Alrowais, Hommood; Kim, Choongsoon; Yeon, Pyungwoo; Ghovanloo, Maysam; Brand, Oliver

    2017-06-27

    Lightweight, flexible, stretchable, and wireless sensing platforms have gained significant attention for personal healthcare and environmental monitoring applications. This paper introduces an all-soft (flexible and stretchable), battery-free, and wireless chemical microsystem using gallium-based liquid metal (eutectic gallium-indium alloy, EGaIn) and poly(dimethylsiloxane) (PDMS), fabricated using an advanced liquid metal thin-line patterning technique based on soft lithography. Considering its flexible, stretchable, and lightweight characteristics, the proposed sensing platform is well suited for wearable sensing applications either on the skin or on clothing. Using the microfluidic sensing platform, detection of liquid-phase and gas-phase volatile organic compounds (VOC) is demonstrated using the same design, which gives an opportunity to have the sensor operate under different working conditions and environments. In the case of liquid-phase chemical sensing, the wireless sensing performance and microfluidic capacitance tunability for different dielectric liquids are evaluated using analytical, numerical, and experimental approaches. In the case of gas-phase chemical sensing, PDMS is used both as a substrate and a sensing material. The gas sensing performance is evaluated and compared to a silicon-based, solid-state gas sensor with a PDMS sensing film.

  6. Single-drop liquid phase microextraction accelerated by surface acoustic wave.

    Science.gov (United States)

    Zhang, Anliang; Zha, Yan

    2013-03-01

    A single-drop liquid phase microextraction method is presented, in which surface acoustic wave (SAW) is used for accelerating extraction speed. A pair of interdigital transducers with 27.5 MHz center frequency is fabricated on a 128° yx-LiNbO3 substrate. A radio frequency signal is applied to one of interdigital transducers to excite SAW. Plastic straw is filled with PDMS, leaving 1 mL for holding sample solution. Plastic straw with sample solution droplet is then dipping into extractant, into which SAW is radiated. Mass transportation from sample solution to extractant drop is accelerated due to acoustic streaming, and extraction time is decreased. An ionic liquid and an acid green-25 solution are used for extraction experiments. Results show that the extraction process is almost finished within 2 min, and extraction speed is increased with radio frequency signal power. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Study of the two-phase liquid loading phenomenon by applying CFD techniques

    Directory of Open Access Journals (Sweden)

    J Vieiro

    2016-09-01

    Full Text Available In order to understand the liquid loading phenomenon, 2D (axisymmetric numerical simulations were performed. This phenomenon appears when the gas velocity reduces to a value below the critical speed of drop extraction in two-phase production wells, and as consequence liquid is accumulated in the tubing, increasing the pressure drop and reducing the flow rate within the tube. Simulations were made using air-water as working fluids over a vertical pipe of 4 meters long through a commercial package of CFD. Comparison between the simulation results and the experimental data available in the literature shows a good capability of homogeneous models to predict the flow characteristics for a given velocity range close to the critical gas velocity; over 100% of this parameter the model significantly overestimates the pressure drop.

  8. Phase-field modeling of isothermal quasi-incompressible multicomponent liquids

    Science.gov (United States)

    Tóth, Gyula I.

    2016-09-01

    In this paper general dynamic equations describing the time evolution of isothermal quasi-incompressible multicomponent liquids are derived in the framework of the classical Ginzburg-Landau theory of first order phase transformations. Based on the fundamental equations of continuum mechanics, a general convection-diffusion dynamics is set up first for compressible liquids. The constitutive relations for the diffusion fluxes and the capillary stress are determined in the framework of gradient theories. Next the general definition of incompressibility is given, which is taken into account in the derivation by using the Lagrange multiplier method. To validate the theory, the dynamic equations are solved numerically for the quaternary quasi-incompressible Cahn-Hilliard system. It is demonstrated that variable density (i) has no effect on equilibrium (in case of a suitably constructed free energy functional) and (ii) can influence nonequilibrium pattern formation significantly.

  9. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, April-June 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-07-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the fourth quarter enthalpy measurements and a preliminary analysis on tetralin data were completed. A new pump was installed eliminating the need for a pressure adjuster in the pressure system. This pump provides pulse free flow even at a pressure of 1500 psia. During the next quarter, measurements on the binary system m-cresol/tetralin will begin. Vapor liquid equilibria measurements for the m-cresol/quinoline system have begun for four isotherms. Preliminary results have been included in this report. These measurements will be completed in the next quarter and work will be started on the m-cresol/tetralin system. 12 refs., 5 figs., 4 tabs.

  10. Density-functional theory and Monte Carlo simulations of the phase behavior of a simple model liquid crystal.

    Science.gov (United States)

    Giura, Stefano; Schoen, Martin

    2014-08-01

    We consider the phase behavior of a simple model of a liquid crystal by means of modified mean-field density-functional theory (MMF DFT) and Monte Carlo simulations in the grand canonical ensemble (GCEMC). The pairwise additive interactions between liquid-crystal molecules are modeled via a Lennard-Jones potential in which the attractive contribution depends on the orientation of the molecules. We derive the form of this orientation dependence through an expansion in terms of rotational invariants. Our MMF DFT predicts two topologically different phase diagrams. At weak to intermediate coupling of the orientation dependent attraction, there is a discontinuous isotropic-nematic liquid-liquid phase transition in addition to the gas-isotropic liquid one. In the limit of strong coupling, the gas-isotropic liquid critical point is suppressed in favor of a fluid- (gas- or isotropic-) nematic phase transition which is always discontinuous. By considering three representative isotherms in parallel GCEMC simulations, we confirm the general topology of the phase diagram predicted by MMF DFT at intermediate coupling strength. From the combined MMF DFT-GCEMC approach, we conclude that the isotropic-nematic phase transition is very weakly first order, thus confirming earlier computer simulation results for the same model [see M. Greschek and M. Schoen, Phys. Rev. E 83, 011704 (2011)].

  11. Solid-phase extraction and reversed-phase high-performance liquid chromatography of the five major alkaloids in Narcissus confusus.

    Science.gov (United States)

    López, Susana; Bastida, Jaume; Viladomat, Francesc; Codina, Carles

    2002-01-01

    A novel, fast and precise method, combining solid-phase extraction and reversed-phase high-performance liquid chromatography is described for the quantitative determination of five alkaloids (galanthamine, N-formylnorgalanthamine, haemanthamine, homolycorine and tazettine/pretazettine) from bulbs of wild Narcissus confusus, a high galanthamine-containing plant species growing in the Iberian Peninsula.

  12. WA105: A large demonstrator of a liquid argon dual phase TPC

    Science.gov (United States)

    Zambelli, L.; Murphy, S.; WA105 Collaboration

    2017-09-01

    The Liquid argon technology has been chosen for the DUNE underground experiment for the study of neutrino oscillations, neutrino astrophysics and proton decay. This detector has excellent tracking and calorimetric capabilities much superior to currently operating neutrino detectors. WA105 is a large demonstrator of the dual-phase liquid argon TPC based on the GLACIER design, with a 6×6×6 m3 (appr. 300t) active volume. Its construction and operation test scalable solutions for the crucial aspects of this detector: ultra-high argon purity in non-evacuable tanks, long drifts, very high drift voltages, large area MPGD, cold preamplifiers. The TPC will be built inside a tank based on industrial LNG technology. Electrons produced in the liquid argon are extracted in the gas phase. Here, a readout plane based on Large Electron Multipliers (LEM’s) provides amplification before the charge collection onto an anode plane with strip readout. This highly cost effective solution provides excellent imaging capabilities with equal charge sharing on both views. PMTs located at the bottom of the tank containing the liquid argon provide the readout of the scintillation light. This demonstrator is an industrial prototype of the design proposed for a large underground detector. WA105 is under construction at CERN and will be exposed to a charged particle beam (0.5 - 20 GeV/c) in the North Area in 2018. The data will provide necessary calibration of the detector performances and benchmark sophisticated reconstruction algorithms. This project is a crucial milestone for the long baseline neutrino program DUNE.

  13. Fluorescence decay of CdSe nanoparticles in Liquid Crystals near Phase Transitions

    Science.gov (United States)

    North, Darren; Beck, Samuel; Gray, Jodie; Drye, Shane; Prayaga, Chandra; Ujj, Laszlo; Royappa, Tim

    2011-03-01

    The liquid crystal 4'octyl-4-cyanobiphenyl (8CB) doped with cadmium selenide nanoparticles (Sigma-Aldrich) was injected into a commercially available liquid crystal cell (INSTEC, Inc). The cell was housed in a temperature controlled environment constructed in the lab and exposed to light from a frequency doubled pulsed Nd: YAG laser. The decay of fluorescence from the sample was measured at several temperatures over the range 25circ; to 45circ; C, covering the smectic-nematic and nematic-isotropic phase transitions. The sample was held at each temperature with a stability and resolution of 1mK before taking the measurement. The fluorescence was detected using a high-speed detector and the decay was measured using a boxcar averager. With the temperature control available, it was possible to approach very close to the phase transitions, with milliKelvin resolution. The results show a significant change in the decay of fluorescence near the nematic-isotropic phase transition.

  14. Characterization of hexacationic imidazolium ionic liquids as effective and highly stable gas chromatography stationary phases.

    Science.gov (United States)

    González-Álvarez, Jaime; Blanco-Gomis, Domingo; Arias-Abrodo, Pilar; Díaz-Llorente, Daniel; Ríos-Lombardía, Nicolás; Busto, Eduardo; Gotor-Fernández, Vicente; Gutiérrez-Álvarez, María D

    2012-01-01

    Polycationic ionic liquids (ILs) are an attractive class of ILs with great potential applicability as gas chromatography stationary phases. A family of hexacationic imidazolium ILs derived from the cycloalkanol family was chemically first prepared in a straightforward manner and then applied for analytical separation purposes. Four tuneable engineering vectors, namely cation ring size structure, anion nature, spatial disposition of cycloalkanol substituents and O-substitution, were considered as experimental parameters for the design of the desired ionic liquids. A total number of five new phases based on a common benzene core respectively exhibited column efficiencies around to 2500 plates/m, broad operating temperature ranges and also, even more importantly, good thermal stabilities (bleeding temperature between 260 and 365°C), finding variations in the selectivity and analytes elution orders depending on the IL structures. Their solvation characteristics were evaluated using the Abraham solvation parameter model, establishing clear correlations between their cation structure and retention capability with respect to certain analytes. The study of relationships between the ILs structure and solvation parameters gives us an idea of the IL stationary phase to be used for specific separations. Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Laser-assisted metal deposition from liquid-phase precursors on polymers

    Science.gov (United States)

    Kordás, K.; Békési, J.; Vajtai, R.; Nánai, L.; Leppävuori, S.; Uusimäki, A.; Bali, K.; George, Thomas F.; Galbács, G.; Ignácz, F.; Moilanen, P.

    2001-03-01

    In this work, a short review is presented for results utilizing the technique of laser-assisted metallization of dielectrics. Experimental efforts and results related to the metal (palladium (Pd), copper (Cu) and silver (Ag)) deposition on polymeric materials (polyimide (PI), mylar) are reported. These polymers and metals are chosen due to their growing importance in the rapidly-developing microelectronics packaging industry. The method of laser-induced chemical liquid-phase deposition (LCLD) offers many advantages compared to other techniques such as laser-induced forward transfer (LIFT), pulsed-laser deposition (PLD) and laser-assisted chemical vapor-phase deposition (LCVD). The LCLD is time and cost effective because vacuum tools and special pre-treatments are not required. The consumed chemicals used in precursors are non-harmful and easy to handle due to the liquid phase. For the optimal physical and chemical properties of deposits, the laser and solution parameters are varied. XeCl and KrF excimer and Ar + lasers are employed for executing the palladium, Ag and/or Cu formation on the polymer substrates. Chemical and physical analyses of the formed metal patterns are performed by EDX, XRD, FESEM, SEM, resistance and adhesion measurements.

  16. A three-dimensional two-phase flow model for a liquid-fed direct methanol fuel cell

    Science.gov (United States)

    Ge, Jiabin; Liu, Hongtan

    A three-dimensional, two-phase, multi-component model has been developed for a liquid-fed DMFC. The modeling domain consists of the membrane, two catalyst layers, two diffusion layers, and two channels. Both liquid and gas phases are considered in the entire anode, including the channel, the diffusion layer and the catalyst layer; while at the cathode, two phases are considered in the gas diffusion layer and the catalyst layer but only single gas phase is considered in the channels. For electrochemical kinetics, the Tafel equation incorporating the effects of two phases is used at both the cathode and anode sides. At the anode side the presence of gas phase reduces the active catalyst areas, while at the cathode side the presence of liquid water reduces the active catalyst areas. The mixed potential effects due to methanol crossover are also included in the model. The results from the two-phase flow mode fit the experimental results better than those from the single-phase model. The modeling results show that the single-phase models over-predict methanol crossover. The modeling results also show that the porosity of the anode diffusion layer plays an important role in the DMFC performance. With low diffusion layer porosity, the produced carbon dioxide cannot be removed effectively from the catalyst layer, thus reducing the active catalyst area as well as blocking methanol from reaching the reaction zone. A similar effect exits in the cathode for the liquid water.

  17. Wettability in the liquid Cu-Ag alloy – fireproof material – gas phase system

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2013-07-01

    Full Text Available In the present paper, results of wettability studies on the liquid metal – fireproof material – gas phase system using copper and Cu-Ag alloys as well as typical fireproof materials, i.e. aluminium oxide, magnesium oxide and graphite, are presented. Contact angle measurements were conducted at 1 373–1 573 K by means of a high-temperature microscope coupled with a camera and a computer equipped with a program for recording and analysing images. For the measurements, the sessile drop method was used.

  18. Gelator-doped liquid-crystal phase grating with multistable and dynamic modes

    Science.gov (United States)

    Lin, Hui-Chi; Yang, Meng-Ru; Tsai, Sheng-Feng; Yan, Shih-Chiang

    2014-01-01

    We demonstrate a gelator-doped nematic liquid-crystal (LC) phase grating, which can be operated in both the multistable mode and the dynamic mode. Thermoreversible association and dissociation of the gelator molecules can vary and fix the multistable diffraction efficiencies of the gratings. A voltage (V) can also be applied to modulate dynamically the diffraction efficiencies of the grating, which behaves as a conventional LC grating. Experimental results show that the variations of the diffraction efficiencies in the multistable and dynamic modes are similar. The maximum diffraction efficiency is approximately 30% at V = 2 V.

  19. Gelator-doped liquid-crystal phase grating with multistable and dynamic modes

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hui-Chi, E-mail: huichilin@nfu.edu.tw; Yang, Meng-Ru; Tsai, Sheng-Feng; Yan, Shih-Chiang [Department of Electro-Optical Engineering, National Formosa University, Yunlin 632, Taiwan (China)

    2014-01-06

    We demonstrate a gelator-doped nematic liquid-crystal (LC) phase grating, which can be operated in both the multistable mode and the dynamic mode. Thermoreversible association and dissociation of the gelator molecules can vary and fix the multistable diffraction efficiencies of the gratings. A voltage (V) can also be applied to modulate dynamically the diffraction efficiencies of the grating, which behaves as a conventional LC grating. Experimental results show that the variations of the diffraction efficiencies in the multistable and dynamic modes are similar. The maximum diffraction efficiency is approximately 30% at V = 2 V.

  20. Transient liquid phase diffusion bonding of Udimet 720 for Stirling power converter applications

    Science.gov (United States)

    Mittendorf, Donald L.; Baggenstoss, William G.

    1992-01-01

    Udimet 720 has been selected for use on Stirling power converters for space applications. Because Udimet 720 is generally considered susceptible to strain age cracking if traditional fusion welding is used, other joining methods are being considered. A process for transient liquid phase diffusion bonding of Udimet 720 has been theoretically developed in an effort to eliminate the strain age crack concern. This development has taken into account such variables as final grain size, joint homogenization, joint efficiency related to bonding aid material, bonding aid material application method, and thermal cycle.

  1. Joining of Ion Transport Membranes Using a Novel Transient Liquid Phase Process

    Energy Technology Data Exchange (ETDEWEB)

    Darryl P. Butt

    2006-08-30

    The feasibility of a novel transient liquid phase (TLP) joining method has been demonstrated in joining La{sub 0.9}Ca{sub 0.1}FeO{sub 3} materials. Metal oxide powders were processed to form the TLP compositions which were used in the joining process. The method has been successful in producing joint interfaces that effectively disappear, as they are the same material and have the same properties as the joined parts. The feasibility of the method has been demonstrated for a single system, but many systems where the method can potentially be applied have been identified.

  2. Mössbauer characterization of joints of steel pieces in transient liquid phase bonding experiences

    Science.gov (United States)

    di Luozzo, N.; Martínez Stenger, P. F.; Canal, J. P.; Fontana, M. R.; Arcondo, B.

    2011-11-01

    Joining of seamless, low carbon, steel tubes were performed by means of Transient Liquid Phase Bonding process employing a foil of Fe-Si-B metallic glass as filler material. The influence of the main parameters of the process was evaluated: temperature, holding time, pressure and post weld heat treatment. Powder samples were obtained from the joint of tubes and characterized employing Mössbauer Spectroscopy in transmission geometry. The sampling was performed both in tubes successfully welded and in those which show joint defects. The results obtained are correlated with the obtained microstructure and the diffusion of Si and B during the process.

  3. Moessbauer characterization of joints of steel pieces in transient liquid phase bonding experiences

    Energy Technology Data Exchange (ETDEWEB)

    Di Luozzo, N.; Martinez Stenger, P. F.; Canal, J. P.; Fontana, M. R.; Arcondo, B., E-mail: barcond@fi.uba.ar [INTECIN (UBA-CONICET), Laboratorio de Solidos Amorfos, Facultad de Ingenieria (Argentina)

    2011-11-15

    Joining of seamless, low carbon, steel tubes were performed by means of Transient Liquid Phase Bonding process employing a foil of Fe-Si-B metallic glass as filler material. The influence of the main parameters of the process was evaluated: temperature, holding time, pressure and post weld heat treatment. Powder samples were obtained from the joint of tubes and characterized employing Moessbauer Spectroscopy in transmission geometry. The sampling was performed both in tubes successfully welded and in those which show joint defects. The results obtained are correlated with the obtained microstructure and the diffusion of Si and B during the process.

  4. The Phase-I Trigger Readout Electronics Upgrade for the ATLAS Liquid-Argon Calorimeters

    CERN Document Server

    Ochoa, Ines; The ATLAS collaboration

    2017-01-01

    Electronics developments are pursued for the trigger readout of the ATLAS Liquid-Argon Calorimeter towards the Phase-I upgrade scheduled in the LHC shut-down period of 2019-2020. The LAr Trigger Digitizer system will digitize 34000 channels at a 40 MHz sampling with 12 bit precision after the bipolar shaper at the front-end system, and transmit to the LAr Digital Processing system in the back-end to extract the transverse energies. Results of ASIC developments including QA and radiation hardness evaluations, and performances on prototypes will presented with the overall system design.

  5. The Trigger Readout Electronics for the Phase-I Upgrade of the ATLAS Liquid Argon Calorimeters

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00389433; The ATLAS collaboration

    2016-01-01

    For the Phase-I luminosity upgrade of the LHC a higher granularity trigger readout of the ATLAS Liquid Argon (LAr) Calorimeters is foreseen to enhance the trigger feature extraction and background rejection. The new readout system digitizes the detector signals, grouped into 34000 so-called Super Cells, with 12bit precision at 40MHz and transfers the data on optical links to the digital processing system, which computes the Super Cell transverse energies. In this paper, development and test results of the new readout system are presented.

  6. Liquid phase methanol reactor staging process for the production of methanol

    Science.gov (United States)

    Bonnell, Leo W.; Perka, Alan T.; Roberts, George W.

    1988-01-01

    The present invention is a process for the production of methanol from a syngas feed containing carbon monoxide, carbon dioxide and hydrogen. Basically, the process is the combination of two liquid phase methanol reactors into a staging process, such that each reactor is operated to favor a particular reaction mechanism. In the first reactor, the operation is controlled to favor the hydrogenation of carbon monoxide, and in the second reactor, the operation is controlled so as to favor the hydrogenation of carbon dioxide. This staging process results in substantial increases in methanol yield.

  7. COMMERCIAL-SCALE DEMONSTRATION OF THE LIQUID PHASE METHANOL (LPMEOH) PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    E.C. Heydorn; B.W. Diamond; R.D. Lilly

    2003-06-01

    This project, which was sponsored by the U.S. Department of Energy (DOE) under the Clean Coal Technology Program to demonstrate the production of methanol from coal-derived synthesis gas (syngas), has completed the 69-month operating phase of the program. The purpose of this Final Report for the ''Commercial-Scale Demonstration of the Liquid Phase Methanol (LPMEOH{trademark}) Process'' is to provide the public with details on the performance and economics of the technology. The LPMEOH{trademark} Demonstration Project was a $213.7 million cooperative agreement between the DOE and Air Products Liquid Phase Conversion Company, L.P. (the Partnership). The DOE's cost share was $92,708,370 with the remaining funds coming from the Partnership. The LPMEOH{trademark} demonstration unit is located at the Eastman Chemical Company (Eastman) chemicals-from-coal complex in Kingsport, Tennessee. The technology was the product of a cooperative development effort by Air Products and Chemicals, Inc. (Air Products) and DOE in a program that started in 1981. Developed to enhance electric power generation using integrated gasification combined cycle (IGCC) technology, the LPMEOH{trademark} Process is ideally suited for directly processing gases produced by modern coal gasifiers. Originally tested at the Alternative Fuels Development Unit (AFDU), a small, DOE-owned process development facility in LaPorte, Texas, the technology provides several improvements essential for the economic coproduction of methanol and electricity directly from gasified coal. This liquid phase process suspends fine catalyst particles in an inert liquid, forming a slurry. The slurry dissipates the heat of the chemical reaction away from the catalyst surface, protecting the catalyst, and allowing the methanol synthesis reaction to proceed at higher rates. The LPMEOH{trademark} Demonstration Project accomplished the objectives set out in the Cooperative Agreement with DOE for this Clean

  8. The quark-gluon-plasma phase transition diagram, Hagedorn matter and quark-gluon liquid

    OpenAIRE

    Zakout, Ismail; Greiner, Carsten

    2010-01-01

    In order to study the nuclear matter in the relativistic heavy ion collisions and the compact stars, we need the hadronic density of states for the entire ($\\mu_B-T$) phase transition diagram. We present a model for the continuous high-lying mass (and volume) spectrum density of states that fits the Hagedorn mass spectrum. This model explains the origin of the tri-critical point besides various phenomena such as the quarkyonic matter and the quark-gluon liquid. The Hagedorn mass spectrum is d...

  9. Selective-Area Micropatterning of Liquid-Phase Epitaxy-Grown Iron Garnet Films

    Science.gov (United States)

    Park, Jae-Hyuk; Cho, Jae-kyeong; Nishimura, Kazuhiro; Uchida, Hironaga; Inoue, Mitsuteru

    2004-07-01

    We investigated selective-area micropatterning of iron garnet film grown by liquid-phase epitaxy (LPE). This method of producing a flat-surface structure overcomes the disadvantages of geometrical grooves, which are formed by wet or dry etching, with a limited resolution due to underetching and nonplanar structure. Moreover, patterned iron garnet films grown by selective-area LPE have better single-crystal properties than films grown by selective-area sputter epitaxy deposition. Thus, this method offers new possibilities for the fabrication of integrated magnetooptic light switch arrays, magnetic waveguides and other magnetooptic devices.

  10. Prediction of gas-liquid two-phase flow regime in microgravity

    Science.gov (United States)

    Lee, Jinho; Platt, Jonathan A.

    1993-01-01

    An attempt is made to predict gas-liquid two-phase flow regime in a pipe in a microgravity environment through scaling analysis based on dominant physical mechanisms. Simple inlet geometry is adopted in the analysis to see the effect of inlet configuration on flow regime transitions. Comparison of the prediction with the existing experimental data shows good agreement, though more work is required to better define some physical parameters. The analysis clarifies much of the physics involved in this problem and can be applied to other configurations.

  11. Acid-Triggered Colorimetric Hydrophobic Benzyl Alcohols for Soluble Tag-Assisted Liquid-Phase Synthesis.

    Science.gov (United States)

    Okada, Yohei; Wakamatsu, Hiroki; Sugai, Masae; Kauppinen, Esko I; Chiba, Kazuhiro

    2015-09-04

    Simple screening of acid-triggered reactions of methoxybenzyl alcohols led to the development of a novel colorimetric hydrophobic benzyl alcohol (HBA) tag. HBA tag-3 (14) retained high solubility in less polar solvents and excellent precipitation properties in polar solvents. Our routine procedure for tag-assisted liquid phase peptide synthesis was applied using HBA tag-3 (14), and an effective synthesis of β-sheet breaker peptide iAβ5 (4) was achieved. The tagged peptides showed a vivid blue color under acidic conditions both on TLC plates and in solution, enabling quantitative assay.

  12. Liquid-gas phase transition and Coulomb instability of asymmetric nuclear systems

    Energy Technology Data Exchange (ETDEWEB)

    Anthony Thomas; P. Wang; D. B. Leinweber; A. G. Williams

    2005-02-01

    We use a chiral SU(3) quark mean field model to study the properties of nuclear systems at finite temperature. The liquid-gas phase transition of symmetric and asymmetric nuclear matter is discussed. For two formulations of the model the critical temperature, T{sub c}, for symmetric nuclear matter is found to be 15.8 MeV and 17.9 MeV. These values are consistent with those derived from recent experiments. The limiting temperatures for finite nuclei are in good agreement with the experimental points.

  13. Ice and liquid partitioning in mid-latitude and artic mixed-phase clouds: how common is the real mixed-phase state

    Science.gov (United States)

    Meyer, Jessica; Krämer, Martina; Afchine, Armin; Gallagher, Martin; Dorsey, James; Brown, Phil; Woolley, Alan; Bierwirth, Eike; Ehrlich, Andre; Wendisch, Manfred; Gehrmann, Martin

    2013-04-01

    The influence of mixed-phase clouds on the radiation budget of the earth is largely unknown. One of the key parameters to determine mixed-phase cloud radiative properties however is the fraction of ice particles and liquid droplets in these clouds. The separate detection of liquid droplets and ice crystals especially in the small cloud particle size range below 50 µm remains challenging though. Here, we present airborne NIXE-CAPS mixed-phase cloud particle measurements observed in mid-latitude and Arctic low-level mixed-phase clouds during the COALESC field campaign in 2011 and the Arctic field campaign VERDI in 2012. NIXE-CAPS (Novel Ice EXpEriment - Cloud and Aerosol Particle Spectrometer, manufactured by DMT) is a cloud particle spectrometer which measures the cloud particle number, size as well as their phase for each cloud particle in the diameter range 0.6 to 945 µm. The common understanding in mixed-phase cloud research is that liquid droplets and ice crystals in the same cloud volume are rather sparse, but instead either liquid droplets or ice crystals are present. However, recently published model studies (e.g. Korolev, A. & Field, P., The effect of dynamics on mixed-phase clouds: Theoretical considerations. J. Atmos. Sci. 65, 66-86, 2008) indicate that a cloud state containing both liquid droplets and ice crystals can be kept up by turbulence. Indeed, our particle by particle analyses of the observed mixed-phase clouds during COALESC and VERDI indicate that the real mixed-phase state is rather common in the atmosphere. The spatial distribution of the mixed-phase ice fraction and the size of the droplets and ice crystals however vary substantially from case to case. The latter parameters seem to be influenced not only by concentration of ice nuclei but also - to a large degree - by cloud dynamics.

  14. Label-free protein sensing by employing blue phase liquid crystal.

    Science.gov (United States)

    Lee, Mon-Juan; Chang, Chung-Huan; Lee, Wei

    2017-03-01

    Blue phases (BPs) are mesophases existing between the isotropic and chiral nematic phases of liquid crystals (LCs). In recent years, blue phase LCs (BPLCs) have been extensively studied in the field of LC science and display technology. However, the application of BPLCs in biosensing has not been explored. In this study, a BPLC-based biosensing technology was developed for the detection and quantitation of bovine serum albumin (BSA). The sensing platform was constructed by assembling an empty cell with two glass slides coated with homeotropic alignment layers and with immobilized BSA atop. The LC cells were heated to isotropic phase and then allowed to cool down to and maintained at distinct BP temperatures for spectral measurements and texture observations. At BSA concentrations below 10-6 g/ml, we observed that the Bragg reflection wavelength blue-shifted with increasing concentration of BSA, suggesting that the BP is a potentially sensitive medium in the detection and quantitation of biomolecules. By using the BPLC at 37 °C and the same polymorphic material in the smectic A phase at 20 °C, two linear correlations were established for logarithmic BSA concentrations ranging from 10-9 to 10-6 g/ml and from 10-6 to 10-3 g/ml. Our results demonstrate the potential of BPLCs in biosensing and quantitative analysis of biomolecules.

  15. Retention mechanisms for basic drugs in the submicellar and micellar reversed-phase liquid chromatographic modes.

    Science.gov (United States)

    Ruiz-Angel, M J; Torres-Lapasió, J R; García-Alvarez-Coque, M C; Carda-Broch, S

    2008-12-15

    The reversed-phase liquid chromatographic (RPLC) behavior (retention, elution strength, selectivity, efficiency, and peak asymmetry) for a group of basic drugs (beta-blockers), with mobile phases containing the anionic surfactant sodium dodecyl sulfate (SDS) and acetonitrile, revealed different separation environments, depending on the concentrations of both modifiers: hydro-organic, submicellar at low surfactant concentration and high concentration of organic solvent, micellar, and submicellar at high concentration of both surfactant and organic solvent. In the surfactant-mediated modes, the anionic surfactant layer adsorbed on the stationary phase interacts strongly with the positively charged basic drugs increasing the retention and masks the silanol groups that are the origin of the poor efficiencies and tailing peaks in hydro-organic RPLC with conventional columns. Also, the strong attraction between the cationic solutes and anionic SDS micelles or monomers in the mobile phase enhances the solubility and allows a direct transfer mechanism of the cationic solutes from micelles to the modified stationary phase, which has been extensively described for highly hydrophobic solutes.

  16. Mathematical modeling of planar and spherical vapor–liquid phase interfaces for multicomponent fluids

    Directory of Open Access Journals (Sweden)

    Celný David

    2016-01-01

    Full Text Available Development of methods for accurate modeling of phase interfaces is important for understanding various natural processes and for applications in technology such as power production and carbon dioxide separation and storage. In particular, prediction of the course of the non-equilibrium phase transition processes requires knowledge of the properties of the strongly curved phase interfaces of microscopic droplets. In our work, we focus on the spherical vapor–liquid phase interfaces for binary mixtures. We developed a robust computational method to determine the density and concentration profiles. The fundamentals of our approach lie in the Cahn-Hilliard gradient theory, allowing to transcribe the functional formulation into a system of ordinary Euler-Langrange equations. This system is then split and modified into a shape suitable for iterative computation. For this task, we combine the Newton-Raphson and the shooting methods providing a good convergence speed. For the thermodynamic roperties, the PC–SAFT equation of state is used. We determine the density and concentration profiles for spherical phase interfaces at various saturation factors for the binary mixture of CO2 and C9H20. The computed concentration profiles allow to the determine the work of formation and other characteristics of the microscopic droplets.

  17. Flow-pattern identification and nonlinear dynamics of gas-liquid two-phase flow in complex networks.

    Science.gov (United States)

    Gao, Zhongke; Jin, Ningde

    2009-06-01

    The identification of flow pattern is a basic and important issue in multiphase systems. Because of the complexity of phase interaction in gas-liquid two-phase flow, it is difficult to discern its flow pattern objectively. In this paper, we make a systematic study on the vertical upward gas-liquid two-phase flow using complex network. Three unique network construction methods are proposed to build three types of networks, i.e., flow pattern complex network (FPCN), fluid dynamic complex network (FDCN), and fluid structure complex network (FSCN). Through detecting the community structure of FPCN by the community-detection algorithm based on K -mean clustering, useful and interesting results are found which can be used for identifying five vertical upward gas-liquid two-phase flow patterns. To investigate the dynamic characteristics of gas-liquid two-phase flow, we construct 50 FDCNs under different flow conditions, and find that the power-law exponent and the network information entropy, which are sensitive to the flow pattern transition, can both characterize the nonlinear dynamics of gas-liquid two-phase flow. Furthermore, we construct FSCN and demonstrate how network statistic can be used to reveal the fluid structure of gas-liquid two-phase flow. In this paper, from a different perspective, we not only introduce complex network theory to the study of gas-liquid two-phase flow but also indicate that complex network may be a powerful tool for exploring nonlinear time series in practice.

  18. Photoinduced crystal-to-liquid phase transitions of azobenzene derivatives and their application in photolithography processes through a solid-liquid patterning.

    Science.gov (United States)

    Norikane, Yasuo; Uchida, Emi; Tanaka, Satoko; Fujiwara, Kyoko; Koyama, Emiko; Azumi, Reiko; Akiyama, Haruhisa; Kihara, Hideyuki; Yoshida, Masaru

    2014-10-03

    The direct and reversible transformation of matter between the solid and liquid phases by light at constant temperature is of great interest because of its potential applications in various manufacturing settings. We report a simple molecular design strategy for the phase transitions: azobenzenes having para-dialkoxy groups with a methyl group at the meta-position. The photolithography processes were demonstrated using the azobenzene as a photoresist in a single process combining development and etching of a copper substrate.

  19. Effectiveness of Liquid-Liquid Extraction, Solid Phase Extraction, and Headspace Technique for Determination of Some Volatile Water-Soluble Compounds of Rose Aromatic Water

    Science.gov (United States)

    2017-01-01

    Steam distillation is used to isolate scent of rose flowers. Rose aromatic water is commonly used in European cuisine and aromatherapy besides its use in cosmetic industry for its lovely scent. In this study, three different sampling techniques, liquid-liquid extraction (LLE), headspace technique (HS), and solid phase extraction (SPE), were compared for the analysis of volatile water-soluble compounds in commercial rose aromatic water. Some volatile water-soluble compounds of rose aromatic water were also analyzed by gas chromatography mass spectrometry (GCMS). In any case, it was concluded that one of the solid phase extraction methods led to higher recoveries for 2-phenylethyl alcohol (PEA) in the rose aromatic water than the liquid-liquid extraction and headspace technique. Liquid-liquid extraction method provided higher recovery ratios for citronellol, nerol, and geraniol than others. Ideal linear correlation coefficient values were observed by GCMS for quantitative analysis of volatile compounds (r2 ≥ 0.999). Optimized methods showed acceptable repeatability (RSDs 95%). For compounds such as α-pinene, linalool, β-caryophyllene, α-humulene, methyl eugenol, and eugenol, the best recovery values were obtained with LLE and SPE. PMID:28791049

  20. Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction for the determination of sulfonamides in animal tissues using high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Zhibing; He, Mengyu; Jiang, Chunzhu; Zhang, Fengqing; Du, Shanshan; Feng, Wennan; Zhang, Hanqi

    2015-12-01

    Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction was developed and applied to the extraction of some sulfonamides, including sulfamerazine, sulfamethazine, sulfathiazole, sulfachloropyridazine, sulfadoxine, sulfisoxazole, and sulfaphenazole, in animal tissues. High-performance liquid chromatography was applied to the separation and determination of the target analytes. The solid sample was directly treated by matrix solid-phase dispersion and the eluate obtained was treated by homogeneous ionic liquid microextraction. The ionic liquid was used as the extraction solvent in this method, which may result in the improvement of the recoveries of the target analytes. To avoid using organic solvent and reduce environmental pollution, water was used as the elution solvent of matrix solid-phase dispersion. The effects of the experimental parameters on recoveries, including the type and volume of ionic liquid, type of dispersant, ratio of sample to dispersant, pH value of elution solvent, volume of elution solvent, amount of salt in eluate, amount of ion-pairing agent (NH4 PF6 ), and centrifuging time, were evaluated. When the present method was applied to the analysis of animal tissues, the recoveries of the analytes ranged from 85.4 to 118.0%, and the relative standard deviations were lower than 9.30%. The detection limits for the analytes were 4.3-13.4 μg/kg. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.