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Sample records for solid phase radioimmunoassay-bead

  1. Solid phase extraction membrane

    SciTech Connect

    Carlson, Kurt C; Langer, Roger L

    2002-11-05

    A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

  2. Solid Phase Micro Extraction (SPME)

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Internation Flavors and Fragrances Inc. proprietary research technology, Solid Phase Micro Extraction (SPME) utilizes a special fiber needle placed directly next to the bloom of the living flower to collect the fragrance molecules. SPME was used in the Space Flower experiment aboard STS-95 space shuttle mission, after which Dr. Braja Mookherjee (left) and Subha Patel of IFF will analyze the effects of gravity on the Overnight Scentsation rose plant.

  3. Colorimetric Solid-Phase Extractor

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The heart of a colorimetric solid phase extractor (CSPE) test kit quickly measures the concentration of the biocides silver or iodine in astronauts' drinking water to determine whether concentrations are safe. When 10 milliliters (ml) of water is drawn through the disk, the disk will turn color (yellow in this picture for iodine) indicating the presence of the biocides. The device could someday be used to test water safety at reservoirs and water treatment plants on Earth. (photo credit: Microanalytical Instrumentation Center, Iowa State University).

  4. Solid phase microextraction field kit

    DOEpatents

    Nunes, Peter J.; Andresen, Brian D.

    2005-08-16

    A field kit for the collection, isolation and concentration of trace amounts of high explosives (HE), biological weapons (BW) and chemical weapons (CW) residues in air, soil, vegetation, swipe, and liquid samples. The field kit includes a number of Solid Phase Microextraction (SPME) fiber and syringe assemblies in a hermetically sealed transportation container or tubes which includes a sampling port, a number of extra SPME fiber and syringe assemblies, the fiber and syringe assemblies including a protective cap for the fiber, and an extractor for the protective cap, along with other items including spare parts, protective glove, and an instruction manual, all located in an airtight container.

  5. Solid Phase Characterization of Solids Recovered from Failed Sluicer Arm

    SciTech Connect

    Cooke, Gary A.

    2015-03-09

    The Enclosure to this memo discusses the solid phase characterization of a solid sample that was retrieved from the single-shell Tank 241-C-111 extended reach sluicer #2. This sluicer, removed from riser #3 on September 25, 2014, was found to have approximately 0.4 gallons of solid tank waste adhering to the nozzle area.

  6. Solid phases in electro- and magnetorheological systems

    NASA Astrophysics Data System (ADS)

    Brandt, Philip C.; Ivlev, Alexei V.; Morfill, Gregor E.

    2009-05-01

    Ensembles of particles with a spherically symmetric repulsive Yukawa interaction and additional dipole-dipole interaction induced by an external field exhibit numerous solid-solid phase transitions controlled by the magnitude of the field. Such interactions emerge most notably in electro- and magnetorheological fluids and plasmas. We propose a simple variational approach based on the Bogoliubov inequality for determining equilibrium solid phases. Phase diagrams for several regimes are calculated and compared with previously performed Monte Carlo and molecular dynamics simulations.

  7. Solid-solid phase transitions via melting in metals.

    PubMed

    Pogatscher, S; Leutenegger, D; Schawe, J E K; Uggowitzer, P J; Löffler, J F

    2016-01-01

    Observing solid-solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid-solid transition via the formation of a metastable liquid in a 'real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory. PMID:27103085

  8. Molecular Modeling of Solid Fluid Phase Behavior

    SciTech Connect

    Peter A. Monson

    2007-12-20

    This report gives a summary of the achievements under DOE contract No. DOE/ER/14150 during the period September 1, 1990 to December 31, 2007. This project was concerned with the molecular modeling of solid-fluid equilibrium. The focus was on understanding how solid-fluid and solid-solid phase behavior are related to molecular structure, and the research program made a seminal contribution in this area. The project led to 34 journal articles, including a comprehensive review article published in Advances in Chemical Physics. The DOE funding supported the work of 5 Ph.D. students, 2 M.S. students and 5 postdoctoral researchers.

  9. Solid phase sequencing of biopolymers

    DOEpatents

    Cantor, Charles R.; Hubert, Koster

    2014-06-24

    This invention relates to methods for detecting and sequencing target nucleic acid sequences, to mass modified nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Probes may be affixed to a solid support such as a hybridization chip to facilitate automated molecular weight analysis and identification of the target sequence.

  10. Solid phase sequencing of biopolymers

    DOEpatents

    Cantor, Charles; Koster, Hubert

    2010-09-28

    This invention relates to methods for detecting and sequencing target nucleic acid sequences, to mass modified nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Nucleic acids whose sequences can be determined include DNA or RNA in biological samples such as patient biopsies and environmental samples. Probes may be fixed to a solid support such as a hybridization chip to facilitate automated molecular weight analysis and identification of the target sequence.

  11. Solid-solid phase transformation: Roughening of stylolites

    NASA Astrophysics Data System (ADS)

    Angheluta, L.; Jettestuen, E.; Mathiesen, J.; Renard, F.; Jamtveit, B.

    2007-12-01

    Sedimentary rocks under uniaxial compression often react by changing the texture during compaction or cementation, which is accompanied by the formation of stylolites spanning the grain contacts or the rocks along surfaces normal to the applied stress. Many field observations corroborate a common feature of stylolites, namely that they are rough interfaces that contain insoluble minerals. Stylolites are outstanding examples of interfacial patterns developed in out-of-equilibrium systems. We study the roughening of stylolites within a model of a moving interface boundary between two stressed solids. The set up of our model consists of two dissimilar elastic bodies that are separated by a sharp interface and subjected to uniform compression in the direction perpendicular to the interface profile. Based on the balance laws of force and energy, we derive the jump conditions for a moving interface driven by a phase transformation process, i.e. the solid phase with higher energy (more porous) is removed and replaced by the same amount of less porous solid phase. An initially flat interface perturbed with small irregularities develops grooves or finger like structures, which align with the principal direction of compaction. The system is dissipative and approaches asymptotically the equilibrium configuration between the two phases. Our numerical investigations reveal several issues: 1) a morphological instability of the solid-solid interface does develop; 2) the instability is driven by the porosity jump across the interface; 3) the energy concentration at the tip of the fingers may influence the development of cracks perpendicular to the stylolites planes, as observed in nature.

  12. Fracture of Materials Undergoing Solid-Solid Phase Transformation

    NASA Astrophysics Data System (ADS)

    Penmecha, Bharat

    A large number of technologically important materials undergo solid-solid phase transformations. Examples range from ferroelectrics (transducers and memory devices), zirconia (Thermal Barrier Coatings) to nickel superalloys and (lithium) iron phosphate (Li-ion batteries). These transformations involve a change in the crystal structure either through diffusion of species or local rearrangement of atoms. This change of crystal structure leads to a macroscopic change of shape or volume or both and results in internal stresses during the transformation. In certain situations this stress field gives rise to cracks (tin, iron phosphate etc.) which continue to propagate as the transformation front traverses the material. In other materials the transformation modifies the stress field around cracks and effects crack growth behavior (zirconia, ferroelectrics). These observations serve as our motivation to study cracks in solids undergoing phase transformations. Understanding these effects will help in improving the mechanical reliability of the devices employing these materials. In this thesis we present work on two problems concerning the interplay between cracks and phase transformations. First, we consider the directional growth of a set of parallel edge cracks due to a solid-solid transformation. We conclude from our analysis that phase transformations can lead to formation of parallel edge cracks when the transformation strain satisfies certain conditions and the resulting cracks grow all the way till their tips cross over the phase boundary. Moreover the cracks continue to grow as the phase boundary traverses into the interior of the body at a uniform spacing without any instabilities. There exists an optimal value for the spacing between the cracks. We ascertain these conclusion by performing numerical simulations using finite elements. Second, we model the effect of the semiconducting nature and dopants on cracks in ferroelectric perovskite materials, particularly

  13. Solid-liquid phase transition in argon

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Tang, H. T.

    1978-01-01

    Starting from the Lennard-Jones interatomic potential, a modified cell theory has been used to describe the solid-liquid phase transition in argon. The cell-size variations may be evaluated by a self-consistent condition. With the inclusion of cell-size variations, the transition temperature, the solid and liquid densities, and the liquid-phase radial-distribution functions have been calculated. These ab initio results are in satisfactory agreement with molecular-dynamics calculations as well as experimental data on argon.

  14. Solid-Solid Phase Transition Kinetics of FOX-7

    SciTech Connect

    Burnham, A K; Weese, R K; Wang, R; Kwok, Q M; Jones, D G

    2005-07-12

    Since it was developed in the late 1990s, 1,1-diamino-2,2-dinitroethene (FOX-7), with lower sensitivity and comparable performance to RDX, has received increasing interest. This paper will present our results for the phase changes of FOX-7 using DSC and HFC (Heat Flow Calorimetry). DSC thermal curves recorded at linear heating rates of 0.10, 0.35 and 1.0 C min{sup -1} show two endothermic peaks and two exothermic peaks. The two endothermic peaks represent solid-solid phase transitions, which have been observed in the literature at 114 C ({beta}-{gamma}) and 159 C ({gamma}-{delta}) by both DSC and XPD (X-ray powder diffraction) measurements. The first transition shifts from 114.5 to 115.8 C as the heating rate increases from 0.10 to 1.0 C min{sup -1}, while the second transition shifts from 158.5 to 160.4 C. Cyclical heating experiments show the endotherms and exotherms for a first heating through the {gamma} phase to the {delta} phase, a cooling and reversion to the {alpha} or {beta} phase, and a second heating to the {gamma} and {delta} phases. The data are interpreted using kinetic models with thermodynamic constraints.

  15. Multiplexed Colorimetric Solid-Phase Extraction

    NASA Technical Reports Server (NTRS)

    Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

    2009-01-01

    Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

  16. Solid-phase fermentation of sweet sorghum

    SciTech Connect

    Bryan, W.L.; Parrish, R.L.

    1982-12-01

    Solid-phase fermentations of chopped Wray sweet sorghum, (0.6 and 2.5 cm size) occurred in 7-liter fermentors at higher rates than juice fermentations and produced 80% ethanol yields, compared to 73% for juice. Heat loss from fermentors limited maximum temperatures to 38 degrees C. Low ethanol yields may have been caused by natural inhibitors or by thermal inhibition.

  17. Astronomical observations of solid phase carbon

    NASA Technical Reports Server (NTRS)

    Jura, M.

    1990-01-01

    In the outer envelopes of red giants, when the gas cools sufficiently, molecules and solids form. Thermodynamically, the most stable molecule is CO, and it is usually assumed that all the available carbon and oxygen are consumed in the formation of this molecule (Salpeter 1977). If the carbon abundance is greater than the oxygen abundance, then the carbon left over after the formation of CO is available for solid grains. Because carbon is by far the most abundant species available for making solids in these environments, researchers anticipate that the grains are composed of nearly pure carbon in some form. The observations which can be used to infer the nature of this solid phase carbon are discussed. The observations of the dust around carbon-rich red giants are discussed. These results are then placed into their broader astrophysical context.

  18. Directed evolution and solid phase enzyme screening

    NASA Astrophysics Data System (ADS)

    Bylina, Edward J.; Grek, Christina L.; Coleman, William J.; Youvan, Douglas C.

    2000-03-01

    A new digital imaging spectrophotometer and a series of colorimetric solid phase arrays have been developed to screen bacterial libraries expressing mutagenized enzymes undergoing directed evolution. This high-throughput solid- phase array system (known as `Kcat Technology') can detect less than a 20% difference in enzyme rates within microcolonies grown at a nearly confluent density of 500 colonies per cm2 on an assay disk. Each microcolony is analyzed simultaneously at single-pixel resolution (1.5 megapixels; 75 micron/pixel), requiring less than 100 nanoliters of substrate per measurement, a 1000-fold reduction over conventional liquid phase assays. Here we report the successful identification of variants of Agrobacterium (beta) -glucosidase--a glycosidase with broad substrate specificity that favors cleavage of glucosides over galactosides--by simultaneously assaying two different substrates tagged with spectrally distinct chromogenic reporters.

  19. GAS PHASE EXPOSURE HISTORY DERIVED FROM MATERIAL PHASE CONCENTRATION PROFILES USING SOLID PHASE MICRO-EXTRACTION

    EPA Science Inventory

    EPA Identifier: F8P31059
    Title: Gas Phase Exposure History Derived from Material Phase Concentration Profiles Using Solid Phase Micro-Extraction
    Fellow (Principal Investigator): Jonathan Lewis McKinney
    Institution: University of Missouri - ...

  20. Solid-phase preparation of protein complexes.

    PubMed

    Pengo, Paolo; Veggiani, Gianluca; Rattanamanee, Kwanchai; Gallotta, Andrea; Beneduce, Luca; Fassina, Giorgio

    2010-01-01

    Protein-protein conjugation is usually achieved by solution phase methods requiring concentrated protein solution and post-synthetic purification steps. In this report we describe a novel continuous-flow solid-phase approach enabling the assembly of protein complexes minimizing the amount of material needed and allowing the repeated use of the same solid phase. The method exploits an immunoaffinity matrix as solid support; the matrix reversibly binds the first of the complex components while the other components are sequentially introduced, thus allowing the complex to grow while immobilized. The tethering technique employed relies on the use of the very mild synthetic conditions and fast association rates allowed by the avidin-biotin system. At the end of the assembly, the immobilized complexes can be removed from the solid support and recovered by lowering the pH of the medium. Under the conditions used for the sequential complexation and recovery, the solid phase was not damaged or irreversibly modified and could be reused without loss of binding capacity. The method was specifically designed to prepare protein complexes to be used in immunometric methods of analysis, where the immunoreactivity of each component needs to be preserved. The approach was successfully exploited for the preparation of two different immunoaffinity reagents with immunoreactivity mimicking native squamous cell carcinoma antigen-immunoglobulin M (SCCA-IgM) and alphafetoprotein-immunoglobulin M (AFP-IgM) immune complexes, which were characterized by dedicated sandwich enzyme-linked immunosorbent assay (ELISA) and immunoblot. Besides the specific application described in the paper, the method is sufficiently general to be used for the preparation of a broad range of protein assemblies. PMID:21038355

  1. Polypyrrole hollow fiber for solid phase extraction.

    PubMed

    Tian, Tian; Deng, Jianjun; Xie, Zhuoying; Zhao, Yuanjin; Feng, Zhangqi; Kang, Xuejun; Gu, Zhongze

    2012-04-21

    We have developed a solid-phase extraction method based on conductive polypyrrole (PPy) hollow fibers which were fabricated by electrospinning and in situ polymerization. The electrospun poly (e-caprolactone) (PCL) fibers were employed as templates for the in situ surface polymerization of PPy under mechanical stirring or ultrasonication to obtain burr-shaped or smooth fiber shells, respectively. Hollow PPy fibers, achieved by removing the PCL templates, were the ideal sorbents for solid phase extraction of polar compounds due to their inherent multi-functionalities. By using the hollow PPy fibers, two important neuroendocrine markers of behavioural disorders, 5-hydroxyindole-3-acetic acid and homovanillic acid, were successfully extracted. Under the optimized conditions, the absolute recoveries of the above two neuroendocrine markers were 90.7% and 92.4%, respectively, in human plasma. Due to its simplicity, selectivity and sensitivity, the method may be applied to quantitatively analyse the concentrations of polar species in complex matrix samples. PMID:22398754

  2. Solid-phase fermentation of sweet sorghum

    SciTech Connect

    Bryan, W.L.; Parrish, R.L.

    1982-12-01

    Solid-phase fermentations of chopped Wray sweet sorghum, (0.6 and 2.5 cm size) occurred in 7-liter fermentors at higher rates than juice fermentations and produced 80% ethanol yields, compared to 73% for juice. Heat loss from fermentors limited maximum temperatures to 38/sup 0/C. Low ethanol yields may have been caused by natural inhibitors or by thermal inhibition.

  3. DNA Extraction: Organic and Solid-Phase.

    PubMed

    Altayari, Wafa

    2016-01-01

    DNA extraction remains a critical step in DNA profiling of biological material recovered from scenes of crime. In the forensic community several methods have gained popularity, including Chelex(®), organic extraction, and solid-phase extraction. While some laboratories streamlined their processes and only use one method we have retained several methods and continue to use these for different sample types. In this chapter we present three methods that have been used for several years in our laboratory. PMID:27259731

  4. Solid-state dimer method for calculating solid-solid phase transitions

    SciTech Connect

    Xiao, Penghao; Henkelman, Graeme; Sheppard, Daniel; Rogal, Jutta

    2014-05-07

    The dimer method is a minimum mode following algorithm for finding saddle points on a potential energy surface of atomic systems. Here, the dimer method is extended to include the cell degrees of freedom for periodic solid-state systems. Using this method, reaction pathways of solid-solid phase transitions can be determined without having to specify the final state structure or reaction mechanism. Example calculations include concerted phase transitions between CdSe polymorphs and a nucleation and growth mechanism for the A15 to BCC transition in Mo.

  5. Fluorous receptor-facilitated solid phase microextraction.

    PubMed

    Lu, Dujuan; Weber, Stephen

    2014-09-19

    Solid phase microextraction (SPME) is a widely accepted solvent-free extraction technique that usually uses a polymer sorbent as the extraction phase. In this work, we have developed receptor-doped fluorous films for solid phase microextraction. The hydrophobic and lipophobic properties of the fluorous films in principle reduce the polymer-water distribution coefficients of solutes other than those that can form noncovalent interactions with the fluorous receptor. This strategy should improve extraction selectivity. We found that the addition of a fluorous carboxylic acid (Krytox 157 FSH) to a fluorous film (Teflon AF 2400) increased the polymer-water distribution coefficients of quinoline, a nitrogen heterocycle. We studied the effects of receptor concentration and solute concentration on the distribution coefficients based on 96-well vessel SPME. We then coated this receptor doped fluorous polymer on a stainless steel fiber for SPME. Compared to a commonly used SPME fiber made of polydimethylsiloxane (PDMS), it showed a preference for the nitrogen heterocyclic compound over a non-heterocyclic control, phenol. To our knowledge, this is the first reported receptor-doped fluorous SPME. PMID:25092595

  6. Solid drop based liquid-phase microextraction.

    PubMed

    Ganjali, Mohammad Reza; Sobhi, Hamid Reza; Farahani, Hadi; Norouzi, Parviz; Dinarvand, Rassoul; Kashtiaray, Amir

    2010-04-16

    Solid drop based liquid-phase microextraction (SDLPME) is a novel sample preparation technique possessing obvious advantages of simple operation with a high pre-concentration factor, low cost and low consumption of organic solvent. SDLPME coupled with gas chromatography (GC), high-performance liquid chromatography (HPLC), and atomic absorption spectrometry (AAS) has been widely applied to the analyses of a different variety of samples. The basic principles, parameters affecting the extraction efficiency, and the latest applications of SDLPME are reviewed in this article. PMID:19962710

  7. Phase Behavior of Complex Superprotonic Solid Acids

    NASA Astrophysics Data System (ADS)

    Panithipongwut, Chatr

    Superprotonic phase transitions and thermal behaviors of three complex solid acid systems are presented, namely Rb3H(SO4) 2-RbHSO4 system, Rb3H(SeO4)2-Cs 3H(SeO4)2 solid solution system, and Cs6 (H2SO4)3(H1.5PO4) 4. These material systems present a rich set of phase transition characteristics that set them apart from other, simpler solid acids. A.C. impedance spectroscopy, high-temperature X-ray powder diffraction, and thermal analysis, as well as other characterization techniques, were employed to investigate the phase behavior of these systems. Rb3H(SO4)2 is an atypical member of the M3H(XO4)2 class of compounds (M = alkali metal or NH4+ and X = S or Se) in that a transition to a high-conductivity state involves disproportionation into two phases rather than a simple polymorphic transition [1]. In the present work, investigations of the Rb3H(SO4)2-RbHSO4 system have revealed the disproportionation products to be Rb2SO 4 and the previously unknown compound Rb5H3(SO 4)4. The new compound becomes stable at a temperature between 25 and 140 °C and is isostructural to a recently reported trigonal phase with space group P3m of Cs5H 3(SO4)4 [2]. At 185 °C the compound undergoes an apparently polymorphic transformation with a heat of transition of 23.8 kJ/mol and a slight additional increase in conductivity. The compounds Rb3H(SeO4)2 and Cs 3H(SeO4)2, though not isomorphous at ambient temperatures, are quintessential examples of superprotonic materials. Both adopt monoclinic structures at ambient temperatures and ultimately transform to a trigonal (R3m) superprotonic structure at slightly elevated temperatures, 178 and 183 °C, respectively. The compounds are completely miscible above the superprotonic transition and show extensive solubility below it. Beyond a careful determination of the phase boundaries, we find a remarkable 40-fold increase in the superprotonic conductivity in intermediate compositions rich in Rb as compared to either end-member. The compound Cs6(H2

  8. Solid-phase extraction in segmented flow.

    PubMed

    Rendl, Martin; Brandstetter, Thomas; Rühe, Jürgen

    2014-11-01

    Two-phase flow systems are increasingly popular for miniaturized, high-throughput performance of analytical or chemical reactions. In this contribution, we extend a previously described method that allows to increase the range of applications of heterogeneous reactions in two-phase flow, i.e., reactions that rely on isolation and purification of the compound of interest for downstream analysis. Our concept is based on liquid plugs, which serve as miniaturized compartments for the analytical reactions. Purification of the target compound is achieved by extracting the analyte from the aqueous compartments using magnetic beads as solid carriers. In the present paper, we elucidate the influence of parameters such as the polarity of the liquid/liquid and solid/liquid interfaces, the magnetic forces and the fluidic conditions onto the extraction performance. The conditions for reliable extraction and purification of the target compounds are determined. Furthermore, we investigate how to facilitate breaking of the plugs through reduction of the surface tension of the solid/liquid interface. When a lower surface tension is employed, a smaller number of beads is required for the extraction process, which implies a higher sensitivity of the device. In addition, we generate channels with different surface chemistries, which are able to manipulate the flow of the two immiscible liquids. We describe a very simple way to generate such devices and show that we can achieve a transition from segmented flow of plugs to a side-by side flow of the two immiscible liquids, a key requirement for the purification of the compounds. PMID:25300748

  9. Solid phase microextraction device using aerogel

    DOEpatents

    Miller, Fred S.; Andresen, Brian D.

    2005-06-14

    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  10. Offline solid phase microextraction sampling system

    DOEpatents

    Harvey, Chris A.

    2008-12-16

    An offline solid phase microextraction (SPME) sampling apparatus for enabling SPME samples to be taken a number of times from a previously collected fluid sample (e.g. sample atmosphere) stored in a fused silica lined bottle which keeps volatile organics in the fluid sample stable for weeks at a time. The offline SPME sampling apparatus has a hollow body surrounding a sampling chamber, with multiple ports through which a portion of a previously collected fluid sample may be (a) released into the sampling chamber, (b) SPME sampled to collect analytes for subsequent GC analysis, and (c) flushed/purged using a fluidically connected vacuum source and purging fluid source to prepare the sampling chamber for additional SPME samplings of the same original fluid sample, such as may have been collected in situ from a headspace.

  11. Graphitized carbons for solid-phase extraction.

    PubMed

    Hennion, M C

    2000-07-14

    The objective of this review is to provide updated information about the most important features of graphitized carbonaceous sorbents used for solid-phase extraction (SPE) of organic compounds from liquid natural matrices or extracts. The surface characteristics of graphitized carbon blacks and porous graphitic carbons are described which are responsible for the various types interactions (hydrophobic, electronic and ion-exchange) with analytes. The method development is given which is based on the prediction from liquid chromatographic retention data obtained using porous graphitic carbon. Emphasis is placed on their capability for trapping very polar and water-soluble analytes from aqueous samples. Comparison is made between carbon-based SPE sorbents and other reversed-phase materials such as octadecyl silicas and highly cross-linked copolymers. Especially, the difficulty encountered for the desorption of some strongly retained analytes is explained by LC data and solutions are given for optimizing the composition and volume of the desorption solution. Many examples illustrate the various common features of graphitized carbons which are the extraction of very polar analytes and multiresidue extractions. Some applications are specific to graphitized carbon black due to the presence of surface functional groups. They include the extraction of anionic compounds such as benzene and naphthalene sulfonates or acidic pesticides. Other applications are specific to porous graphitic carbon due to its flat and homogeneous surface. One example is the trace extraction of coplanar polychlorinated biphenyls (PCBs), dibenzo-p-dioxins and dibenzofurans from other PCB congeners. PMID:10941668

  12. Nanostructured carbons for solid phase extraction

    NASA Astrophysics Data System (ADS)

    Puziy, A. M.; Poddubnaya, O. I.; Gawdzik, B.; Sobiesiak, M.; Reinish, C. A.; Tsyba, M. M.; Segeda, T. P.; Danylenko, M. I.

    2010-06-01

    Nanostructured carbons have been obtained by the template method using zeolite NaY and silica gels (SG60, Fluka and ZK, POCh) as structure directing agents. Texture and porous structure of carbons were characterized by TEM, XRD and nitrogen adsorption. Surface chemistry was investigated by the potentiometric titration method. It has been shown that all carbons show developed and uniform porous structure with mean size in the micropore range (1.1 nm) for zeolite derived carbon and in the mesopore range (3.4 and 4.8 nm) for silica gel derived carbons. The BET surface area of silica gel derived carbons is in the range 1230-1280 m 2/g whereas zeolite derived carbon possesses very high BET surface area, 3000 m 2/g. Potentiometric titration showed that carbons obtained by the template method contain significant amount of acid surface groups (carboxylic, lactone/enol and phenolic) with the total amount 1.1-1.5 mmol/g. To study adsorption-desorption properties of nanostructured carbons towards phenol and chlorophenols the solid phase extraction method was used. High recoveries of chlorophenols were obtained (80-93%) at the breakthrough volumes 1700-3000 mL. The recoveries are much higher than that obtained with commercially available carbon ACC (Supelco).

  13. Theory and practice of solid phase microextraction

    SciTech Connect

    Pawliszyn, J.; Zhang, Zhouyao; Gorecki, T.

    1995-12-31

    Solid Phase Microextraction (SPME) involves exposing a fused silica fibre that has been coated with a non-volatile polymeric liquid to a sample or its headspace. The absorbed analytes are thermally desorbed in the injector of a gas chromatograph (GC) or GC-mass spectrometer. The fibre is contained in a syringe-like SPME device to facilitate convenient handling. This method can be applied to liquid, gaseous or headspace samples. All three sample can be analyzed on the same instrument without modifications to the GC and the extraction and the sample injection process can be fully automated using conventional autosampler. The fibre can be used to extract target analytes directly in the field without collecting a sample. Because of its cylindrical geometry it cannot be plugged. All three sample types can be analyzed on the isothermal instrument. Advantageous of SPME will be discussed using important applications - semi-volatile and volatile compounds in air, aqueous matrices and in the headspace above dirty aqueous samples, slurries and soils.

  14. Solid phase bioremediation of petroleum contaminated soils

    SciTech Connect

    Potter, C.D.

    1992-11-01

    Solid phase bioremediation of petroleum contaminated soil involves aerobic biodegradation in an above grade treatment bed. This treatment technology is proposed for remediating soils contaminated by petroleum from leaking underground fuel storage tanks at various sites at the Oak Ridge Y-12 Plant. The treatment technology uses bacteria to degrade the petroleum hydrocarbons. The environmentally safe end products of the biodegradation process are carbon dioxide and water. A large, relatively level area is required to construct the perimeter berms, place the liner, and spread the contaminated soil in a 1 to 2 foot thick layer. A porous media is placed on top of the liner for protection and for proper drainage of leachate. Water, nutrients, and microorganisms are introduced into the soil in the treatment bed using conventional agricultural spraying techniques. Oxygen is supplied to the soil by periodic tilling on an ``as needed`` basis. To prevent soil erosion and to minimize leachate production during precipitation events, the treatment bed is completely covered by a plastic film. The treatment process is expected to require 3 to 8 months after construction is completed.

  15. Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry

    NASA Technical Reports Server (NTRS)

    Hill, Carol M.; Street, Kenneth W.; Tanner, Stephen P.; Philipp, Warren H.

    2000-01-01

    Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

  16. Solid-solid phase transitions determined by differential scanning calorimetry.

    NASA Technical Reports Server (NTRS)

    Murrill, E.; Whitehead, M. E.; Breed, L.

    1972-01-01

    Data are presented to show that tris(hydroxymethyl)acetic acid, monochloropentaerythritol, monofluoropentaerythritol, difluoropentaerythritol, monoaminopentaerythritol, and diaminopentaerythritol exhibit solid-state transitions to a plastic crystalline state. Transitional enthalpies in many of these substances are lower than might be expected by analogy with related structures, suggesting that some configurational contributions to their entropy increments have been inhibited.

  17. Air sampling with solid phase microextraction

    NASA Astrophysics Data System (ADS)

    Martos, Perry Anthony

    There is an increasing need for simple yet accurate air sampling methods. The acceptance of new air sampling methods requires compatibility with conventional chromatographic equipment, and the new methods have to be environmentally friendly, simple to use, yet with equal, or better, detection limits, accuracy and precision than standard methods. Solid phase microextraction (SPME) satisfies the conditions for new air sampling methods. Analyte detection limits, accuracy and precision of analysis with SPME are typically better than with any conventional air sampling methods. Yet, air sampling with SPME requires no pumps, solvents, is re-usable, extremely simple to use, is completely compatible with current chromatographic equipment, and requires a small capital investment. The first SPME fiber coating used in this study was poly(dimethylsiloxane) (PDMS), a hydrophobic liquid film, to sample a large range of airborne hydrocarbons such as benzene and octane. Quantification without an external calibration procedure is possible with this coating. Well understood are the physical and chemical properties of this coating, which are quite similar to those of the siloxane stationary phase used in capillary columns. The log of analyte distribution coefficients for PDMS are linearly related to chromatographic retention indices and to the inverse of temperature. Therefore, the actual chromatogram from the analysis of the PDMS air sampler will yield the calibration parameters which are used to quantify unknown airborne analyte concentrations (ppb v to ppm v range). The second fiber coating used in this study was PDMS/divinyl benzene (PDMS/DVB) onto which o-(2,3,4,5,6- pentafluorobenzyl) hydroxylamine (PFBHA) was adsorbed for the on-fiber derivatization of gaseous formaldehyde (ppb v range), with and without external calibration. The oxime formed from the reaction can be detected with conventional gas chromatographic detectors. Typical grab sampling times were as small as 5 seconds

  18. Crystal-Phase Control by Solution-Solid-Solid Growth of II-VI Quantum Wires.

    PubMed

    Wang, Fudong; Buhro, William E

    2016-02-10

    A simple and potentially general means of eliminating the planar defects and phase alternations that typically accompany the growth of semiconductor nanowires by catalyzed methods is reported. Nearly phase-pure, defect-free wurtzite II-VI semiconductor quantum wires are grown from solid rather than liquid catalyst nanoparticles. The solid-catalyst nanoparticles are morphologically stable during growth, which minimizes the spontaneous fluctuations in nucleation barriers between zinc blende and wurtzite phases that are responsible for the defect formation and phase alternations. Growth of single-phase (in our cases the wurtzite phase) nanowires is thus favored. PMID:26731426

  19. Solid lubrication design methodology, phase 2

    NASA Technical Reports Server (NTRS)

    Pallini, R. A.; Wedeven, L. D.; Ragen, M. A.; Aggarwal, B. B.

    1986-01-01

    The high temperature performance of solid lubricated rolling elements was conducted with a specially designed traction (friction) test apparatus. Graphite lubricants containing three additives (silver, phosphate glass, and zinc orthophosphate) were evaluated from room temperature to 540 C. Two hard coats were also evaluated. The evaluation of these lubricants, using a burnishing method of application, shows a reasonable transfer of lubricant and wear protection for short duration testing except in the 200 C temperature range. The graphite lubricants containing silver and zinc orthophosphate additives were more effective than the phosphate glass material over the test conditions examined. Traction coefficients ranged from a low of 0.07 to a high of 0.6. By curve fitting the traction data, empirical equations for slope and maximum traction coefficient as a function of contact pressure (P), rolling speed (U), and temperature (T) can be developed for each lubricant. A solid lubricant traction model was incorporated into an advanced bearing analysis code (SHABERTH). For comparison purposes, preliminary heat generation calculations were made for both oil and solid lubricated bearing operation. A preliminary analysis indicated a significantly higher heat generation for a solid lubricated ball bearing in a deep groove configuration. An analysis of a cylindrical roller bearing configuration showed a potential for a low friction solid lubricated bearing.

  20. Solid state phase detector replaces bulky transformer circuit

    NASA Technical Reports Server (NTRS)

    Moberly, C. L.

    1967-01-01

    Miniature solid state phase detector using MOSFETs is used in a phase lock loop with a sun-bit detector in an integrated data-link circuit. This replaces bulky transformer circuits. It uses an inverter amplifier, a modulator switch, and a buffer amplifier.

  1. Diagnostic immunoassay by solid phase separation for digoxin

    SciTech Connect

    Grenier, F.C.; Pry, T.A.; Kolaczkowski, L.

    1988-11-29

    A method is described for conducting a diagnostic immunoassay for digoxin, comprising: (a) forming a reaction mixture of a test sample with a molar excess of labeled anti-digoxin antibodies whereby the labeled antibodies are capable of forming complex with digoxin present in the sample; (b) contacting the reaction mixture with a solid phase material having immobilized thereon a compound; (c) separating the solid phase material from the reaction mixture; and (d) determining the presence of digoxin in the test sample by measuring the amount of complex present in the liquid phase.

  2. Electron-solid and electron-liquid phases in graphene

    NASA Astrophysics Data System (ADS)

    Knoester, M. E.; Papić, Z.; Morais Smith, C.

    2016-04-01

    We investigate the competition between electron-solid and quantum-liquid phases in graphene, which arise in partially filled Landau levels. The differences in the wave function describing the electrons in the presence of a perpendicular magnetic field in graphene with respect to the conventional semiconductors, such as GaAs, can be captured in a form factor which carries the Landau-level index. This leads to a quantitative difference in the electron-solid and -liquid energies. For the lowest Landau level, there is no difference in the wave function of relativistic and nonrelativistic systems. We compute the cohesive energy of the solid phase analytically using a Hartree-Fock Hamiltonian. The liquid energies are computed analytically as well as numerically, using exact diagonalization. We find that the liquid phase dominates in the n =1 Landau level, whereas the Wigner crystal and electron-bubble phases become more prominent in the n =2 and 3 Landau level.

  3. Solid-liquid phase boundaries of lens protein solutions.

    PubMed Central

    Berland, C R; Thurston, G M; Kondo, M; Broide, M L; Pande, J; Ogun, O; Benedek, G B

    1992-01-01

    We report measurement of the solid-liquid phase boundary, or liquidus line, for aqueous solutions of three pure calf gamma-crystallin proteins: gamma II, gamma IIIa, and gamma IIIb. We also studied the liquidus line for solutions of native gamma IV-crystallin calf lens protein, which consists of 85% gamma IVa/15% gamma IVb. In all four proteins the liquidus phase boundaries lie higher in temperature than the previously determined liquid-liquid coexistence curves. Thus, over the range of concentration and temperature for which liquid-liquid phase separation occurs, the coexistence of a protein crystal phase with a protein liquid solution phase is thermodynamically stable relative to the metastable separated liquid phases. The location of the liquidus lines clearly divides these four crystallin proteins into two groups: those in which liquidus lines flatten at temperatures greater than 70 degrees C: gamma IIIa and gamma IV, and those in which liquidus lines flatten at temperatures less than 50 degrees C: gamma II and gamma IIIb. We have analyzed the form of the liquidus lines by using specific choices for the structures of the Gibbs free energy in solution and solid phases. By applying the thermodynamic conditions for equilibrium between the two phases to the resulting chemical potentials, we can estimate the temperature-dependent free energy change upon binding of protein and water into the solid phase. PMID:1741375

  4. Solids mixing in a three phase fluidized bed containing spherically shaped-porous solid particles

    NASA Astrophysics Data System (ADS)

    Snell, G. J.; Zopff, D.

    1984-05-01

    Solids mixing a 3 phase fluidized bed containing 1.8 mm nominal diameter porous spherically shaped solids was studied using a batch type tracer technique. High speed photography was used to determine concentration time traces of color code solid tracer in a region near the wall of a 2 in. i.d. fluidization tube, located at a vertical elevation about 7 in. above the distributor. An add mixture of water and gaseous nitrogen at room temperature and essentially ambient pressure was used to fluidize a spherically shaped, nickel molybdate on alumina solid phase throughout this study. An empirical steady state mixing time was defined in order to characterize top to bottom of bed solids mixing. This mixing index was in turn correlated with superficial liquid velocity, superficial gas velocity, and an axial characteristic dimension.

  5. Solid state photomultiplier for astronomy, phase 2

    NASA Technical Reports Server (NTRS)

    Besser, P. J.; Hays, K. M.; Laviolette, R. A.

    1989-01-01

    Epitaxial layers with varying donor concentration profiles were grown on silicon substrate wafers using chemical vapor deposition (CVD) techniques, and solid state photomultiplier (SSPM) devices were fabricated from the wafers. Representative detectors were tested in a low background photon flux, low temperature environment to determine the device characteristics for comparison to NASA goals for astronomical applications. The SSPM temperatures varied between 6 and 11 K with background fluxes in the range from less than 5 x 10 to the 6th power to 10 to the 13th power photons/square cm per second at wavelengths of 3.2 and 20 cm. Measured parameters included quantum efficiency, dark count rate and bias current. Temperature for optimal performance is 10 K, the highest ever obtained for SSPMs. The devices exhibit a combination of the lowest dark current and highest quantum efficiency yet achieved. Experimental data were reduced, analyzed and used to generate recommendations for future studies. The background and present status of the microscopic theory of SSPM operation were reviewed and summarized. Present emphasis is on modeling of the avalanche process which is the basis for SSPM operation. Approaches to the solution of the Boltzmann transport equation are described and the treatment of electron scattering mechanisms is presented. The microscopic single-electron transport theory is ready to be implemented for large-scale computations.

  6. Phase State and Dynamics of Fluids in Mesoporous Solids

    NASA Astrophysics Data System (ADS)

    Valiullin, Rustem

    2011-03-01

    Fundamental understanding of the correlations between the phase state and dynamics of fluids confined to mesoporous solids is an important prerequisite for their optimal use in practical applications. The present contribution describes some recent progress in the exploration of such interrelations using nuclear magnetic resonance. In particular, transport properties of fluids during gas-liquid, solid-liquid and liquid-liquid transitions occurring in pore spaces of mesoporous solids are discussed and are shown to bear strong correlations. From the results presented it will, in particular, become evident that molecular diffusivity is a sensitive microscopic parameter not only to the thermodynamic state of the system, but also the history of its preparation.

  7. Multiferroic property of colloidal crystals with three-dimensional solid-solid phase transitions

    NASA Astrophysics Data System (ADS)

    Huang, J. P.; Shen, X. Y.; Chen, Y. X.

    2015-08-01

    It is a challenge to understand the dynamics of ubiquitous solid-solid phase transitions in three dimensions. In this direction, colloidal crystals are often adopted as a model system for investigation, because they contain highly ordered arrays of colloidal microparticles, analogous to atomic or molecular counterparts with appropriate scaling. Here, by resorting to the Ewald-Kornfeld formulation, we describe a type of solid-solid phase transitions from the body-centered tetragonal lattice, to the face-centered cubic lattice, and then to subsequent lattices, which have been experimentally demonstrated in electro-magnetorheological fluids (which contain suspended microparticles enabling the formation of crystalline structures) subjected to crossed electric and magnetic fields. As a result, we find that each lattice exhibits specific multiferroic properties at room temperature. The findings are further confirmed by independent finite-element simulations. Despite some limitations (e.g., the specific value of change in magnetization is small during phase transitions), this work suggests a way to real-time measure the microscopic dynamics of three-dimensional solid-solid phase transitions in colloidal crystals by detecting their multiferroic properties.

  8. Two-step nucleation mechanism in solid-solid phase transitions

    NASA Astrophysics Data System (ADS)

    Peng, Yi; Wang, Feng; Wang, Ziren; Alsayed, Ahmed M.; Zhang, Zexin; Yodh, Arjun G.; Han, Yilong

    2015-01-01

    The microscopic kinetics of ubiquitous solid-solid phase transitions remain poorly understood. Here, by using single-particle-resolution video microscopy of colloidal films of diameter-tunable microspheres, we show that transitions between square and triangular lattices occur via a two-step diffusive nucleation pathway involving liquid nuclei. The nucleation pathway is favoured over the direct one-step nucleation because the energy of the solid/liquid interface is lower than that between solid phases. We also observed that nucleation precursors are particle-swapping loops rather than newly generated structural defects, and that coherent and incoherent facets of the evolving nuclei exhibit different energies and growth rates that can markedly alter the nucleation kinetics. Our findings suggest that an intermediate liquid should exist in the nucleation processes of solid-solid transitions of most metals and alloys, and provide guidance for better control of the kinetics of the transition and for future refinements of solid-solid transition theory.

  9. Molecular Simulation of Solid-Fluid Phase Coexistence

    NASA Astrophysics Data System (ADS)

    Agrawal, Rupal

    1995-01-01

    A novel molecular simulation technique--Gibbs -Duhem integration method--provides the framework for the study of phase equilibria involving ordered phases, particularly solids. The technique allows coexistence to be determined by just one simulation, without ever attempting or performing particle insertions. This is achieved by thermodynamic integration along a path that coincides with the saturation line. This thesis aims at the development of simulation tools--in particular the Gibbs-Duhem technique--that can be used by researchers in molecular thermodynamics especially for the study of solids. The effect of both repulsive and attractive intermolecular forces on transitions involving two and three-phases for various model systems has been studied. We demonstrate how the Gibbs-Duhem integration technique may be modified to determine the phase diagram along a path in which the intermolecular potential itself varies. In particular, the method has been applied to evaluate solid-fluid coexistence for the inverse-power potential as a function of potential softness. Freezing into both fcc and bcc crystals has been investigated. The complete phase diagram for the Lennard-Jones model has also been determined and several semi-empirical 'melting rules' are examined in the light of these results. We also evaluate three-phase equilibria as a function of the intermolecular potential (a path that transforms the Lennard-Jones model into a square well model is defined). The first estimate of solid-liquid equilibrium for a square well model is also given. Solid-liquid-vapor triple point as a function of square well width has been computed. Isotropic -nematic transition for hard-ellipsoid mixtures as a model for liquid crystalline systems has also been studied. In addition, a thorough error analysis has been performed for the Gibbs-Duhem integration technique. We have also introduced a new simulation technique which is capable of determining the entire phase coexistence curve in a

  10. Theory of phase transitions in disordered crystal solids

    NASA Astrophysics Data System (ADS)

    Li, Huaming

    Solid-state amorphization of a crystalline solid to an amorphous phase is extensively studied as a first order phase transition at low temperature for almost thirty years. Many similarities between heat-induced melting and solid-state amorphization have been recognized and a generalized Lindemann melting criterion has been built by focusing on the total mean-square atomic displacement as a generic measure of crystalline disorder in metastable solid solutions. In this dissertation, we report the recent progress on phenomenological models employed for thermodynamic description of macroscopic systems and fluctuations and nucleation of mesoscopic inhomogeneous systems in binary solid solutions under polymorphic constraints with no long-range diffusion involved. Based on our understanding on atomic picture of solid-state amorphization in binary solid solutions, we propose a Landau free energy to describe amorphization as the first order phase transition. The order parameter is defined which represents the loss of long-range translational order. The elastic strain field induced by composition disorder plays the important role through the bilinear coupling with the order parameter. Elastic softening and amorphization happen simultaneously. From the similarity between the melting and amorphization, we use the temperature and composition as two external variables and treat solid-state amorphization as low temperature melting under polymorphic constraints. For homogeneous system, the phase diagrams for endothermic melting and exothermic melting are built separately and the corresponding thermodynamic quantities are presented. A microscopic homogeneous nucleation mechanism is proposed conceptually in binary solid solutions under polymorphic constraints. The formation of an amorphous embryo is initiated from the composition modulation in the crystal state and a subsequent polymorphous nucleation within the as-formed heterophase fluctuation. This homogeneous nucleation path is

  11. Liquid-solid and solid-solid phase transition of monolayer water: High-density rhombic monolayer ice

    NASA Astrophysics Data System (ADS)

    Kaneko, Toshihiro; Bai, Jaeil; Yasuoka, Kenji; Mitsutake, Ayori; Zeng, Xiao Cheng

    2014-05-01

    Liquid-solid and solid-solid phase transitions of a monolayer water confined between two parallel hydrophobic surfaces are studied by molecular dynamics simulations. The solid phase considered is the high-density rhombic monolayer ice. Based on the computed free energy surface, it is found that at a certain width of the slit nanopore, the monolayer water exhibits not only a high freezing point but also a low energy barrier to crystallization. Moreover, through analyzing the oxygen-hydrogen-oxygen angle distribution and oxygen-hydrogen radial distribution, the high-density monolayer ice is classified as either a flat ice or a puckered ice. The transition between a flat ice and a puckered ice reflects a trade-off between the water-wall interactions and the electrostatic interactions among water molecules.

  12. Liquid-solid and solid-solid phase transition of monolayer water: high-density rhombic monolayer ice.

    PubMed

    Kaneko, Toshihiro; Bai, Jaeil; Yasuoka, Kenji; Mitsutake, Ayori; Zeng, Xiao Cheng

    2014-05-14

    Liquid-solid and solid-solid phase transitions of a monolayer water confined between two parallel hydrophobic surfaces are studied by molecular dynamics simulations. The solid phase considered is the high-density rhombic monolayer ice. Based on the computed free energy surface, it is found that at a certain width of the slit nanopore, the monolayer water exhibits not only a high freezing point but also a low energy barrier to crystallization. Moreover, through analyzing the oxygen-hydrogen-oxygen angle distribution and oxygen-hydrogen radial distribution, the high-density monolayer ice is classified as either a flat ice or a puckered ice. The transition between a flat ice and a puckered ice reflects a trade-off between the water-wall interactions and the electrostatic interactions among water molecules. PMID:24832288

  13. Influence of impurities on the solid-solid phase transitions in zirconium

    SciTech Connect

    Rigg, Paulo A; Greeff, Carl W; Gray, George T., III; Knudson, Marcus D

    2009-08-04

    In an effort to better understand the influence of impurities on the solid-solid phase transitions in Group IVb metals, experiments have been carried out on polycrystalline zirconium samples using plate impact and isentropic loading techniques. Samples with three levels of impurities were shock-loaded using both gas and powder-driven guns and isentropically loaded using magnetic drive (Sandia's Z-Machine) to determine the properties and characteristics of both the {alpha} {yields} {omega} and {omega} {yields} {beta} transitions.

  14. Neutron Scattering Studies of Pre-Transitional Effects in Solid-Solid Phase Transformations

    SciTech Connect

    Shapiro, S. M.

    1999-06-30

    Neutron scattering studies have played a fundamental role in understanding solid-solid phase transformations, particularly in studying the lattice dynamical behavior associated with precursor effects. A review of the studies performed on solids exhibiting Martensitic transformations is given below. The mode softening and associated elastic diffuse scattering, previously observed in NiAl alloys, will be discussed as well as more recent work on Ni{sub 2}MnGa, a system exhibiting magnetic order as well as a Martensitic transformation. Also, new results on the precursor effects in ordered and disordered FePt alloys will be presented.

  15. Solid–solid phase transitions via melting in metals

    PubMed Central

    Pogatscher, S.; Leutenegger, D.; Schawe, J. E. K.; Uggowitzer, P. J.; Löffler, J. F.

    2016-01-01

    Observing solid–solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid–solid transition via the formation of a metastable liquid in a ‘real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory. PMID:27103085

  16. All solid-state SBS phase conjugate mirror

    DOEpatents

    Dane, C.B.; Hackel, L.A.

    1999-03-09

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

  17. All solid-state SBS phase conjugate mirror

    DOEpatents

    Dane, Clifford B.; Hackel, Lloyd A.

    1999-01-01

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases.

  18. Solid Phase DNA Amplification: A Simple Monte Carlo Lattice Model

    NASA Astrophysics Data System (ADS)

    Mercier, Jean-Francois; Slater, Gary W.; Mayer, Pascal

    2003-03-01

    Recently, a new type of PCR called solid phase DNA amplification, has been introduced where surface-bound instead of freely-diffusing primers are used to amplify DNA. This type of amplification is limited to two-dimensional surfaces and therefore allows the easy parallelization of the PCR process in a single system. Furthermore, solid phase DNA amplification could provide an alternate route to DNA target implantation on DNA chips for genomic studies. We propose a simple Lattice Monte Carlo model of solid phase DNA amplification. We study the growth, stability and morphology of isolated PCR colonies under various conditions. Our results indicate that, in most cases, solid phase DNA amplification is characterized by a geometric growth and a rather sharp size distribution. These results are qualitatively different those obtained for liquid PCR processes which are usually characterized (at least initially) by an exponential growth and a broad population distribution. Various non-ideal effects are studied, and we demonstrate that such effects do not generally change the nature of the process, except in extreme cases.

  19. Solid-phase-supported synthesis of morpholinoglycine oligonucleotide mimics

    PubMed Central

    Belov, Sergey S; Tarasenko, Yulia V; Silnikov, Vladimir N

    2014-01-01

    Summary An efficient solid-phase-supported peptide synthesis (SPPS) of morpholinoglycine oligonucleotide (MorGly) mimics has been developed. The proposed strategy includes a novel specially designed labile linker group containing the oxalyl residue and the 2-aminomethylmorpholino nucleoside analogues as first subunits. PMID:24991266

  20. Recent Approaches Toward Solid Phase Synthesis of β-Lactams

    NASA Astrophysics Data System (ADS)

    Mandal, Bablee; Ghosh, Pranab; Basu, Basudeb

    Since the discovery of penicillin in 1929, β-lactam antibiotics have been recognized as potentially chemotherapeutic drugs of incomparable effectiveness, conjugating a broad spectrum of activity with very low toxicity. The primary motif azetidin-2-one ring (β-lactam) has been considered as specific pharmacophores and scaffolds. With the advent of combinatorial chemistry and automated parallel synthesis coupled with ample interests from the pharmaceutical industries, recent trends have been driven mostly by adopting solid phase techniques and polymer-supported synthesis of β-lactams. The present survey will present an overview of the developments on the polymer-supported and solid phase techniques for the preparation of β-lactam ring or β-lactam containing antibiotics published over the last decade. Both unsubstituted and substitutions with different functional groups at various positions of β-lactams have been synthesized using solid phase technology. However, Wang resin and application of Staudinger [2+2] cycloaddition reaction have remained hitherto the major choice. It may be expected that other solid phase approaches involving different resins would be developed in the coming years.

  1. Traceless solid-phase synthesis of heterosteroid framework.

    PubMed

    Hong, B C; Chen, Z Y; Chen, W H

    2000-08-24

    [reaction: see text]A traceless solid-phase synthesis of cyclopenta[c]-4H-chromen-8-ol, benzo[d]cyclopenta[e]-3H-3-azin-8-ol, and other 11-heterosteroids via the fulvene hetero [6 + 3] cycloaddition is described. PMID:10990418

  2. Kinetics of Microbial Reduction of Solid Phase U(VI)

    SciTech Connect

    Liu, Chongxuan; Jeon, Byong Hun; Zachara, John M.; Wang, Zheming; Dohnalkova, Alice; Fredrickson, Jim K.

    2006-10-01

    Sodium boltwoodite (NaUO2SiO3OH ?1.5H2O) was used to assess the kinetics of microbial reduction of solid phase U(VI) by a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. The bioreduction kinetics was studied with Na-boltwoodite in suspension or within alginate beads. Concentrations of U(VI)tot and cell number were varied to evaluate the coupling of U(VI) dissolution, diffusion, and microbial activity. Batch experiments were performed in a non-growth medium with lactate as electron donor at pH 6.8 buffered with PIPES. Microscopic and spectroscopic analyses with transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and laser-induced fluorescence spectroscopy (LIFS) collectively indicated that solid phase U(VI) was first dissolved and diffused out of grain interiors before it was reduced on bacterial surfaces and/or within the periplasm. The kinetics of solid phase U(VI) bioreduction was well described by a coupled model of bicarbonate-promoted dissolution of Na-boltwoodite, intraparticle uranyl diffusion, and Monod type bioreduction kinetics with respect to dissolved U(VI) concentration. The results demonstrated the intimate coupling of biological, chemical, and physical processes in microbial reduction of solid phase U(VI).

  3. Solid phases of spatially nanoconfined oxygen: A neutron scattering study

    SciTech Connect

    Kojda, Danny; Wallacher, Dirk; Hofmann, Tommy; Baudoin, Simon; Hansen, Thomas; Huber, Patrick

    2014-01-14

    We present a comprehensive neutron scattering study on solid oxygen spatially confined in 12 nm wide alumina nanochannels. Elastic scattering experiments reveal a structural phase sequence known from bulk oxygen. With decreasing temperature cubic γ-, orthorhombic β- and monoclinic α-phases are unambiguously identified in confinement. Weak antiferromagnetic ordering is observed in the confined monoclinic α-phase. Rocking scans reveal that oxygen nanocrystals inside the tubular channels do not form an isotropic powder. Rather, they exhibit preferred orientations depending on thermal history and the very mechanisms, which guide the structural transitions.

  4. Solid phases of spatially nanoconfined oxygen: a neutron scattering study.

    PubMed

    Kojda, Danny; Wallacher, Dirk; Baudoin, Simon; Hansen, Thomas; Huber, Patrick; Hofmann, Tommy

    2014-01-14

    We present a comprehensive neutron scattering study on solid oxygen spatially confined in 12 nm wide alumina nanochannels. Elastic scattering experiments reveal a structural phase sequence known from bulk oxygen. With decreasing temperature cubic γ-, orthorhombic β- and monoclinic α-phases are unambiguously identified in confinement. Weak antiferromagnetic ordering is observed in the confined monoclinic α-phase. Rocking scans reveal that oxygen nanocrystals inside the tubular channels do not form an isotropic powder. Rather, they exhibit preferred orientations depending on thermal history and the very mechanisms, which guide the structural transitions. PMID:24437900

  5. The solid phase of ginkgolide K: Structure and physicochemical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Yiwen; Zhang, Guoshun; Wang, Zhenzhong; Lv, Yang; Xiao, Wei

    2016-05-01

    Four solvates of ginkgolide K with dimethyl sulfoxide(I), water molecule(II), acetone-isopropyl alcohol(III), methanol-ethanol(IV) and one solvate-free (V) have been described in this work. And the solid-state techniques such as X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy were used for characterization of the solid phases. The single crystal structures of ginkgolide K solvates (I-IV) have been determined. Ginkgolide K shows strong inflexibility and solvents being incorporated in the crystal structure results in it forming polymorphs via the diverse hydrogen bond interactions.

  6. Phenomena of solid state grain boundaries phase transition in technology

    NASA Astrophysics Data System (ADS)

    Minaev, Y. A.

    2015-03-01

    The results of study the phenomenon, discovered by author (1971), of the phase transition of grain boundary by the formation of two-dimensional liquid or quasi-liquid films have been done. The described phenomena of the first order phase transition (two-dimensional melting) at temperatures 0.6 - 0.9 TS0 (of the solid state melting point) is a fundamental property of solid crystalline materials, which has allowed to revise radically scientific representations about a solid state of substance. Using the mathematical tools of the film thermodynamics it has been obtained the generalized equation of Clausius - Clapeyron type for two-dimensional phase transition. The generalized equation has been used for calculating grain boundary phase transition temperature TSf of any metal, which value lies in the range of (0.55…0.86) TS0. Based on these works conclusions the develop strategies for effective forming of coatings (by thermo-chemical processing) on surface layers of functional alloys and hard metals have been made. The short overview of the results of some graded alloys characterization has been done.

  7. Phenomena of solid state grain boundaries phase transition in technology

    SciTech Connect

    Minaev, Y. A.

    2015-03-30

    The results of study the phenomenon, discovered by author (1971), of the phase transition of grain boundary by the formation of two-dimensional liquid or quasi-liquid films have been done. The described phenomena of the first order phase transition (two-dimensional melting) at temperatures 0.6 – 0.9 T{sub S0} (of the solid state melting point) is a fundamental property of solid crystalline materials, which has allowed to revise radically scientific representations about a solid state of substance. Using the mathematical tools of the film thermodynamics it has been obtained the generalized equation of Clausius - Clapeyron type for two-dimensional phase transition. The generalized equation has been used for calculating grain boundary phase transition temperature T{sub Sf} of any metal, which value lies in the range of (0.55…0.86) T{sub S0}. Based on these works conclusions the develop strategies for effective forming of coatings (by thermo-chemical processing) on surface layers of functional alloys and hard metals have been made. The short overview of the results of some graded alloys characterization has been done.

  8. Studies in Solid Phase Peptide Synthesis: A Personal Perspective

    SciTech Connect

    Mitchell, A R

    2007-06-01

    By the early 1970s it had became apparent that the solid phase synthesis of ribonuclease A could not be generalized. Consequently, virtually every aspect of solid phase peptide synthesis (SPPS) was reexamined and improved during the decade of the 1970s. The sensitive detection and elimination of possible side reactions (amino acid insertion, N{sup {alpha}}-trifluoroacetylation, N{sup {alpha}{var_epsilon}}-alkylation) was examined. The quantitation of coupling efficiency in SPPS as a function of chain length was studied. A new and improved support for SPPS, the 'PAM-resin', was prepared and evaluated. These and many other studies from the Merrifield laboratory and elsewhere increased the general acceptance of SPPS leading to the 1984 Nobel Prize in Chemistry for Bruce Merrifield.

  9. Infrared imaging of a solid phase surfactant monolayer.

    PubMed

    Conover, T A; Saylor, J R

    2006-08-01

    A new method for visualizing solid phase surfactant monolayers is presented. This method utilizes infrared (IR) imaging of the surface of a warm subphase covered by the monolayer. When the subphase is deep, natural convection occurs, resulting in a complex surface temperature field that is easily visualized using an IR camera. The presence of a surfactant monolayer changes the hydrodynamic boundary condition at the interface, dramatically altering the surface temperature field, and permitting the differentiation of surfactant-covered and surfactant-free regions. In this work, solid phase monolayers are imaged using this IR method. Fractures in the monolayer are dramatically visualized because of the sudden elimination of surfactant in the region opened up by the crack. The method is demonstrated in a wind/water tunnel, where a stearic acid monolayer is deposited and a crack is created through shear on the surfactant surface, created by suddenly increasing the velocity of the air over the water. PMID:16863234

  10. Solid-Phase Biological Assays for Drug Discovery

    NASA Astrophysics Data System (ADS)

    Forsberg, Erica M.; Sicard, Clémence; Brennan, John D.

    2014-06-01

    In the past 30 years, there has been a significant growth in the use of solid-phase assays in the area of drug discovery, with a range of new assays being used for both soluble and membrane-bound targets. In this review, we provide some basic background to typical drug targets and immobilization protocols used in solid-phase biological assays (SPBAs) for drug discovery, with emphasis on particularly labile biomolecular targets such as kinases and membrane-bound receptors, and highlight some of the more recent approaches for producing protein microarrays, bioaffinity columns, and other devices that are central to small molecule screening by SPBA. We then discuss key applications of such assays to identify drug leads, with an emphasis on the screening of mixtures. We conclude by highlighting specific advantages and potential disadvantages of SPBAs, particularly as they relate to particular assay formats.

  11. Allantoin as a solid phase adsorbent for removing endotoxins.

    PubMed

    Vagenende, Vincent; Ching, Tim-Jang; Chua, Rui-Jing; Gagnon, Pete

    2013-10-01

    In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ∼80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance. PMID:24001944

  12. New Phase Transition of Solid Bromine under High Pressure

    SciTech Connect

    San-Miguel, A.; Libotte, H.; Gaspard, J.-P.; Gauthier, M.; Aquilanti, G.; Pascarelli, S.

    2007-07-06

    Solid bromine has been studied by x-ray absorption spectroscopy experiments up to a maximum pressure of 75 GPa. The data analysis of the extended fine structure reveals that the intramolecular distance first increases, reaching its maximum value at 25{+-}5 GPa. From this value the intramolecular distance abruptly begins to decrease evidencing a nonpreviously observed phase transformation taking place at 25{+-}5 GPa. A maximum variation of 0.08 A ring is observed at 65{+-}5 GPa where again a phase transition occurs. This last transformation could correspond with the recently observed change to an incommensurate modulated phase. We discuss the possible generalization of the observed new phase transition at 25{+-}5 GPa to the case of the other halogens.

  13. Oscillatory burning of solid propellants including gas phase time lag.

    NASA Technical Reports Server (NTRS)

    T'Ien, J. S.

    1972-01-01

    An analysis has been performed for oscillatory burning of solid propellants including gas phase time lag. The gaseous flame is assumed to be premixed and laminar with a one-step overall chemical reaction. The propellant is assumed to decompose according to the Arrenhius Law, with no condensed phase reaction. With this model, strong gas phase resonance has been found in certain cases at the characteristic gas-phase frequencies, but the peaking of the acoustic admittance is in the direction favoring the damping of pressure waves. At still higher frequencies, moderate wave-amplifying ability was found. The limit of low frequency response obtained previously by Denison and Baum was recovered, and the limitations of the quasi-steady theory were investigated.

  14. Molecular dynamics and the phase transition in solid C60

    NASA Astrophysics Data System (ADS)

    Tycko, R.; Dabbagh, G.; Fleming, R. M.; Haddon, R. C.; Makhija, A. V.; Zahurak, S. M.

    1991-09-01

    The molecular reorientational dynamics in two phases of solid C60 with C-13 NMR measurements are characterized. A change in the nature of the dynamics, indicated by a change in kinetic parameters extracted from spin-lattice relaxation data, occurs at the phase transition at 260 K. Above the transition, the molecules appear to execute continuous rotational diffusion; below the transition, they appear to jump between symmetry-equivalent orientations. This interpretation is consistent with the X-ray-diffraction results of Heiney et al. (1991) as well as the NMR relaxation and spectral data.

  15. Diffusion-controlled grain growth in two-phase solids

    SciTech Connect

    Fan, D.; Chen, L.Q.

    1997-08-01

    Microstructural evolution and the kinetics of grain growth in volume-conserved two-phase solids were investigated using two-dimensional (2-D) computer simulations based on a diffuse-interface field model. In this model, a two-phase microstructure is described by non-conserved field variables which represent crystallographic orientations of grains in each phase and by a conserved composition field variable which distinguishes the compositional difference between the two phases. The temporal and spatial evolution of these field variables were obtained through a numerical solution to the time-dependent Ginzburg-Landau (TDGL) equations. The effect of the ratios of grain boundary energies to interfacial energy on the microstructure features was systematically studied. It was found that grain growth in a volume-conserved two-phase solid is controlled by long-range diffusion and follows the power growth law, R{sup m} {minus} R{sup m}{sub o} = kt with m = 3 in the scaling regime for all cases studied, including the microstructures containing only quadrijunctions. The effects of volume fractions and initial microstructures are discussed.

  16. Clinically relevant interpretation of solid phase assays for HLA antibody

    PubMed Central

    Bettinotti, Maria P.; Zachary, Andrea A.; Leffell, Mary S.

    2016-01-01

    Purpose of review Accurate and timely detection and characterization of human leukocyte antigen (HLA) antibodies are critical for pre-transplant and post-transplant immunological risk assessment. Solid phase immunoassays have provided increased sensitivity and specificity, but test interpretation is not always straightforward. This review will discuss the result interpretation considering technical limitations; assessment of relative antibody strength; and the integration of data for risk stratification from complementary testing and the patient's immunological history. Recent findings Laboratory and clinical studies have provided insight into causes of test failures – false positive reactions because of antibodies to denatured HLA antigens and false negative reactions resulting from test interference and/or loss of native epitopes. Test modifications permit detection of complement-binding antibodies and determination of the IgG subclasses. The high degree of specificity of single antigen solid phase immunoassays has revealed the complexity and clinical relevance of antibodies to HLA-C, HLA-DQ, and HLA-DP antigens. Determination of antibody specificity for HLA epitopes enables identification of incompatible antigens not included in test kits. Summary Detection and characterization of HLA antibodies with solid phase immunoassays has led to increased understanding of the role of those antibodies in graft rejection, improved treatment of antibody-mediated rejection, and increased opportunities for transplantation. However, realization of these benefits requires careful and accurate interpretation of test results. PMID:27200498

  17. Nuclear Ordered Phases of Solid 3He in Silver Sinters

    NASA Astrophysics Data System (ADS)

    Schuberth, Erwin A.; Kath, Matthias; Bago, Simone

    2006-09-01

    To determine the exact spin structure of the nuclear magnetic ordered phases of solid 3He, the U2D2 low field and the high field phases above 0.4 T, a European Research and Training Network for neutron scattering from the ordered solid was established which consisted of a collaboration with the Hahn Meitner Institute, Berlin, and other European and US groups. For this experiment it is crucial to grow a single crystal within the sinter needed for cooling the solid to temperatures of the order of 500 μK and to keep it cold long enough to measure a magnetic neutron diffraction. The sinter is also necessary to absorb the major part (> 90%) of the heat generated by the neutron capture and decay reaction of the 3He nucleus. In this work we studied the growth of crystals in Ag sinters of different pore sizes and with different growth speeds to find an optimal way to obtain single crystalline samples, or at least samples with only a few grains. We used SQUID magnetometry and NMR to measure the magnetization in the ordered phases. They were indicated by the known drop of the intensity, both in the NMR signal and in the dc magnetization, for the U2D2 phase, and by an increase of about 30% for the high field phase. The best results for cooling were obtained with sinters made from 700 Å "Japanese powder" with a packing fraction of 50% which were annealed at 130 °C after sintering and then had a calculated particle size of about 4200 Å. In the dc magnetization we found a paramagnetic surface contribution from a few monolayers of 3He down to 500 μK in addition to the bulk magnetization.

  18. Phase field modeling and simulation of three-phase flow on solid surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Xiao-Ping

    2016-08-01

    Phase field models are widely used to describe the two-phase system. The evolution of the phase field variables is usually driven by the gradient flow of a total free energy functional. The generalization of the approach to an N phase (N ≥ 3) system requires some extra consistency conditions on the free energy functional in order for the model to give physically relevant results. A projection approach is proposed for the derivation of a consistent free energy functional for the three-phase Cahn-Hilliard equations. The system is then coupled with the Navier-Stokes equations to describe the three-phase flow on solid surfaces with moving contact line. An energy stable scheme is developed for the three-phase flow system. The discrete energy law of the numerical scheme is proved which ensures the stability of the scheme. We also show some numerical results for the dynamics of triple junctions and four phase contact lines.

  19. Solid State NMR Studies of the Aluminum Hydride Phases

    NASA Technical Reports Server (NTRS)

    Hwang, Son-Jong; Bowman, R. C., Jr.; Graetz, Jason; Reilly, J. J.

    2006-01-01

    Several solid state NMR techniques including magic-angle-spinning (MAS) and multiple-quantum (MQ) MAS experiments have been used to characterize various AlH3 samples. MAS-NMR spectra for the 1H and 27Al nuclei have been obtained on a variety of AlH3 samples that include the (beta)- and (gamma)- phases as well as the most stable (alpha)-phase. While the dominant components in these NMR spectra correspond to the aluminum hydride phases, other species were found that include Al metal, molecular hydrogen (H2), as well as peaks that can be assigned to Al-O species in different configurations. The occurrence and concentration of these extraneous components are dependent upon the initial AlH3 phase composition and preparation procedures. Both the (beta)-AlH3 and (gamma)-AlH3 phases were found to generate substantial amounts of Al metal when the materials were stored at room temperature while the (alpha)-phase materials do not exhibit these changes.

  20. Heat transfer in different phases of solid cyclohexene

    NASA Astrophysics Data System (ADS)

    Konstantinov, V. A.; Krivchikov, A. I.; Korolyuk, O. A.; Revyakin, V. P.; Sagan, V. V.; Vdovichenko, G. A.; Zvonaryova, A. V.

    2013-09-01

    The thermal conductivity of solid cyclohexene C6H10 has been measured in two independent experiments in five different stable and metastable phase states: orientational glass (Ig), orientational glass (IIIg) with a partial order, dynamically orientationally disordered state (III) with a partial order, completely orientationally ordered phase (II) and “plastic” phase (I). The measurements were carried out at saturated vapor pressure in the temperature range 2-120 K and at isochoric conditions in “plastic” and orientationally ordered phases on samples of different densities. The isochoric thermal conductivity of “plastic” phase increases smoothly with temperature. It can be attributed to weakening of the translational orientational coupling which, in turn, leads to a decrease in phonon scattering on rotational excitations. The thermal conductivity of cyclohexene measured at saturated vapor pressure exhibits a similar behavior in phases Ig, IIIg, and II. At low temperatures (T<8 K) the thermal conductivity tends to T2 dependence, passes through a maximum and decreases further with increasing temperature following the dependence, which is somewhat different from 1/T. It was found that the thermal conductivity can be represented as a sum of two contributions κ(T)=κ1(T)+κ2(T), where κ1(T) is due to propagating phonons whose mean-free path exceeds half the phonon wavelength, and κ2(T) is attributed to localized short-wavelength or “diffusive” vibrational modes.

  1. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling...

  2. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling...

  3. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling...

  4. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling...

  5. Solid phase extraction of petroleum carboxylic acids using a functionalized alumina as stationary phase.

    PubMed

    de Conto, Juliana Faccin; Nascimento, Juciara dos Santos; de Souza, Driele Maiara Borges; da Costa, Luiz Pereira; Egues, Silvia Maria da Silva; Freitas, Lisiane Dos Santos; Benvenutti, Edilson Valmir

    2012-04-01

    Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples. The proposed study aimed to recover acid compounds using the solid phase extraction method, employing different types of commercial stationary ion exchange phases (SAX and NH(2)) and new phase alumina functionalized with 1,4-bis(n-propyl)diazoniabicyclo[2.2.2]octane chloride silsesquioxane (Dab-Al(2)O(3)), synthesized in this work. Carboxylic acids were used as standard mixture in the solid phase extraction for further calculation of recovery yield. Then, the real sample (petroleum) was fractionated into saturates, aromatics, resins, and asphaltenes, and the resin fraction of petroleum (B1) was eluted through stationary ion exchange phases. The stationary phase synthesized in this work showed an efficiency of ion exchange comparable to that of the commercial stationary phases. PMID:22589166

  6. Solid-phase fluorescence spectroscopy to characterize organic wastes.

    PubMed

    Muller, Mathieu; Milori, Débora Marcondes Bastos Pereira; Déléris, Stéphane; Steyer, Jean-Philippe; Dudal, Yves

    2011-01-01

    The production of solid organic waste (SOW) such as sewage sludge (SS) or municipal solid waste (MSW) has been continuously increasing in Europe since the beginning of the 1990'. Today, the European Union encourages the stabilization of these wastes using biologic processes such as anaerobic digestion and/or composting to produce bio-energy and organic fertilizers. However, the design and management of such biologic processes require knowledge about the quantity and quality of the organic matter (OM) contained in the SOW. The current methods to characterize SOW are tedious, time-consuming and often insufficiently informative. In this paper, we assess the potential of solid-phase fluorescence (SPF) spectroscopy to quickly provide a relevant characterization of SOW. First, we tested well known model compounds (tryptophan, bovine serum albumin, lignin and humic acid) and biologic matrix (Escherichia coli) in three dimensional solid-phase fluorescence (3D-SPF) spectroscopy. We recorded fluorescence spectra from proteinaceous samples but we could not record the fluorescence emitted by lignin and humic acid powders. For SOW samples, fluorescence spectra were successfully recorded for MSW and most of its sub-components (foods, cardboard) but impossible for SS, sludge compost (SC) and ligno-cellulosic wastes. Based on visual observations and additional assays, we concluded that the presence of highly light-absorptive chemical structures in such dark-colored samples was responsible for this limitation. For such samples, i.e. lignin, humic acid, SS, SC and ligno-cellulosic wastes, we show that laser induced fluorescence (LIF) spectroscopy enables the acquisition of 2D fluorescence spectra. PMID:21696938

  7. A hybrid solid-fluorous phase radioiodination and purification platform.

    PubMed

    Dzandzi, James P K; Vera, Denis R Beckford; Valliant, John F

    2014-07-01

    A new class of fluorous materials was developed to create a hybrid solid-solution phase strategy for the expedient preparation and HPLC-free purification of (125) I-labeled compounds. The system is referred to as a hybrid platform in that it combines solution phase labeling and fluorous solid-phase purification in one step as opposed to two separate individual processes. Treatment of fluorous arylstannanes coated on fluorous silica with [(125) I]NaI and the appropriate oxidant made it possible to produce and selectively isolate the nonfluorous radiolabeled products in high purity (>98%) free from excess starting material and unreacted radioiodine. Examples included simple aryl and heterocyclic (click) derivatives, known radiopharmaceuticals including meta-iodobenzylguanidine (MIBG) and iododeoxyuridine (IUdR), and a new agent with high affinity for prostate-specific membrane antigen. The coated fluorous silica kits are simple to prepare, and reactions can be performed at room temperature using different oxidants generating products in minutes in biocompatible solutions. PMID:25069901

  8. Solid Phase Synthesis of Helically Folded Aromatic Oligoamides.

    PubMed

    Dawson, S J; Hu, X; Claerhout, S; Huc, I

    2016-01-01

    Aromatic amide foldamers constitute a growing class of oligomers that adopt remarkably stable folded conformations. The folded structures possess largely predictable shapes and open the way toward the design of synthetic mimics of proteins. Important examples of aromatic amide foldamers include oligomers of 7- or 8-amino-2-quinoline carboxylic acid that have been shown to exist predominantly as well-defined helices, including when they are combined with α-amino acids to which they may impose their folding behavior. To rapidly iterate their synthesis, solid phase synthesis (SPS) protocols have been developed and optimized for overcoming synthetic difficulties inherent to these backbones such as low nucleophilicity of amine groups on electron poor aromatic rings and a strong propensity of even short sequences to fold on the solid phase during synthesis. For example, acid chloride activation and the use of microwaves are required to bring coupling at aromatic amines to completion. Here, we report detailed SPS protocols for the rapid production of: (1) oligomers of 8-amino-2-quinolinecarboxylic acid; (2) oligomers containing 7-amino-8-fluoro-2-quinolinecarboxylic acid; and (3) heteromeric oligomers of 8-amino-2-quinolinecarboxylic acid and α-amino acids. SPS brings the advantage to quickly produce sequences having varied main chain or side chain components without having to purify multiple intermediates as in solution phase synthesis. With these protocols, an octamer could easily be synthesized and purified within one to two weeks from Fmoc protected amino acid monomer precursors. PMID:27586338

  9. Heterogeneous Phase Transfer Catalysis in Solid Phase Syntheses of Anth-Cyclic Tetrapeptides.

    PubMed

    Xin, Dongyue; Yuan, Jian; Wong, Kwok-Yin; Burgess, Kevin

    2016-09-01

    This study features solid phase syntheses of cyclic tetrapeptides containing anthranilic acid (Anth) on relatively inexpensive resins derived from polystyrene. It proved to be difficult to hydrolyze a supported Anth-methyl ester unless a phase transfer catalyst was added to facilitate transport of hydroxide into the swollen hydrophobic gel state of the resin. We suggest this may be an under-appreciated strategy for improving syntheses on polystyrene supports. PMID:27552148

  10. Advances in solid-phase extraction disks for environmental chemistry

    USGS Publications Warehouse

    Thurman, E.M.; Snavely, K.

    2000-01-01

    The development of solid-phase extraction (SPE) for environmental chemistry has progressed significantly over the last decade to include a number of new sorbents and new approaches to SPE. One SPE approach in particular, the SPE disk, has greatly reduced or eliminated the use of chlorinated solvents for the analysis of trace organic compounds. This article discusses the use and applicability of various SPE disks, including micro-sized disks, prior to gas chromatography-mass spectrometry for the analysis of trace organic compounds in water. Copyright (C) 2000 Elsevier Science B.V.

  11. Liquid/solid/dual phase xenon γ-ray detectors

    NASA Astrophysics Data System (ADS)

    van Sonsbeek, R.; Bom, V. R.; van Eijk, C. W. E.; Hollander, R. W.; Meijvogel, K.; Okx, W. J. C.

    1994-09-01

    It is recognized by various groups in the world that liquid xenon (LXe) is an interesting medium for the detection of γ-rays. In spite of all the experimental and theoretical effort expended during recent years, the processes that take place in this medium are not yet fully understood. We have obtained some preliminary results using an ionization chamber with a Frisch grid. This chamber could be filled with LXe and with solid xenon (SXe). We also investigated dual phase (GXe/SXe) systems. Our study will be continued with a newly developed detection cell described in this article.

  12. Progress of solid-phase microextraction coatings and coating techniques.

    PubMed

    Jiang, Guibin; Huang, Minjia; Cai, Yaqi; Lv, Jianxia; Zhao, Zongshan

    2006-07-01

    Solid-phase microextraction (SPME) has been popular as an environmentally friendly sample pretreatment technique to extract a very wide range of analytes. This is partly owing to the development of SPME coatings. One of the key factors affecting the extraction performances, such as the sensitivity, selectivity, and reproducibility, is the properties of the coatings on SPME fibers. This paper classifies the materials used as SPME coatings and introduces some common preparation techniques of SPME coating in detail, such as sol-gel technique, electrochemical polymerization technique, particle direct pasting technique, restricted access matrix SPME technique, and molecularly imprinted SPME technique. PMID:16884587

  13. Liquid and Solid Phases of 3He on Graphite

    NASA Astrophysics Data System (ADS)

    Gordillo, M. C.; Boronat, J.

    2016-04-01

    Recent heat-capacity experiments show quite unambiguously the existence of a liquid 3He phase adsorbed on graphite. This liquid is stable at an extremely low density, possibly one of the lowest found in nature. Previous theoretical calculations of the same system, and in strictly two dimensions, agree with the result that this liquid phase is not stable and the system is in the gas phase. We calculated the phase diagram of normal 3He adsorbed on graphite at T =0 using quantum Monte Carlo methods. Considering a fully corrugated substrate, we observe that at densities lower than 0.006 Å-2 the system is a very dilute gas that, at that density, is in equilibrium with a liquid of density 0.014 Å-2 . Our prediction matches very well the recent experimental findings on the same system. On the contrary, when a flat substrate is considered, no gas-liquid coexistence is found, in agreement with previous calculations. We also report results on the different solid structures, and on the corresponding phase transitions that appear at higher densities.

  14. Kinetics of solid-solid phase transitions in metals using proton radiography (u)

    SciTech Connect

    Schwartz, Cynthia L; Rigg, Paulo A; Hixson, Rob S; Jensen, Brian J

    2011-01-25

    When a compressed material changes phase it doesn't do so instantly. Instead it transitions through a mixed phase as it transforms to the end state phase for a given pressure, volume and temperature. Common phase diagrams show the phase boundaries as sharp lines when compression has been slowly applied and held for an infinite amount of time. When the compression is applied with high strain rate, however, the phase boundaries are no longer crisp as the kinetic effects of the crystal reorientation delay the transitions, resulting in regions of mixed phase. This opens up the possibility that some degree of metastability exists for such transition in dynamic compression. The compression path can go past the equilibrium phase boundary and the transition happen from a metastable state because of the very short timescale of the compression process. Molecular dynamics (MD) simulations recently have been used to examine shock-induced phase transitions in single crystal materials illustrating an orientation dependence of the transition stress, mechanisms, kinetics, and Hugoniot response. For example, the [100] orientation of iron had a simulated transition stress higher than the experimentally determined polycrystalline value of 13 GPa by 2 GPa. Previously, dynamic experiments on iron have observed a non-zero transition time and width in the solid-solid {alpha}-{var_epsilon} phase transition. Using Proton Radiography at the Los Alamos Neutron Science Center, we have performed plate impact experiments on iron to further study the {alpha}-{var_epsilon} phase transition which occurs at 13 GPa. A 40mm bore powder gun was coupled to a proton radiography beam line and imaging system and synchronized to the impact of the projectile on the target sample with the proton beam pattern. A typical experimental configuration for the iron study, as shown below in 3 color-enhanced radiographs, is a 40mm diameter aluminum sabot impacting a 40mm diameter sample of polycrystalline ARMCO iron

  15. Electrostatic levitation studies of supercooled liquids and metastable solid phases

    NASA Astrophysics Data System (ADS)

    Rustan, Gustav Errol

    been carried out to study the metastable phase formation in an Fe83B17 near eutectic alloy. Initial supercooling measurements using the ISU-ESL identified the formation of three metastable phases: a precipitate phase that shows stable coexistence with the deeply supercooled liquid, and two distinct bulk solidification phases. To identify the structure of the metastable phases, the Washington University Beamline ESL (WU-BESL) has been used to perform in-situ high energy x-ray diffraction measurements of the metastable phases. Based on the x-ray results, the precipitate phase has been identified as bcc-Fe, and the more commonly occurring bulk solidification product has been found to be a two-phase mixture of Fe23B6 plus fcc-Fe, which appears, upon cooling, to transform into a three phase mixture of Fe23B6, bcc-Fe, and an as-yet unidentified phase, with the transformation occurring at approximately the expected fcc-to-bcc transformation temperature of pure Fe. To further characterize the multi-phase metastable alloy, the ISU-ESL has been used to perform measurements of volume thermal expansion via the videographic technique, as well as RF susceptibility via the TDO technique. The results of the thermal expansion and susceptibility data have been found to be sensitive indicators of additional structural changes that may be occurring in the metastable solid at temperatures below 1000 K, and the susceptibility data has revealed that three distinct ferromagnetic phase transitions take place within the multi-phase mixture. Based on these results, it has been hypothesized that there may be an additional transformation taking place that leads to the formation of either bct- or o-Fe3B in addition to the Fe23B6 phase, although further work is required to test this hypothesis.

  16. Nucleation of the diamond phase in aluminium-solid solutions

    NASA Technical Reports Server (NTRS)

    Hornbogen, E.; Mukhopadhyay, A. K.; Starke, E. A., Jr.

    1993-01-01

    Precipitation was studied from fcc solid solutions with silicon, germanium, copper and magnesium. Of all these elements only silicon and germanium form diamond cubic (DC) precipitates in fcc Al. Nucleation of the DC structure is enhanced if both types of atom are dissolved in the fcc lattice. This is interpreted as due to atomic size effects in the prenucleation stage. There are two modes of interference of fourth elements with nucleation of the DC phase in Al + Si, Ge. The formation of the DC phase is hardly affected if the atoms (for example, copper) are rejected from the (Si, Ge)-rich clusters. If additional types of atom are attracted by silicon and/or germanium, DC nuclei are replaced by intermetallic compounds (for example Mg2Si).

  17. Quantum phase transitions around the staggered valence-bond solid

    SciTech Connect

    Xu Cenke; Balents, Leon

    2011-07-01

    Motivated by recent numerical results, we study the quantum phase transitions between Z{sub 2} spin-liquid, Neel-ordered, and various valence-bond solid (VBS) states on the honeycomb and square lattices, with emphasis on the staggered VBS. In contrast to the well-understood columnar VBS order, the staggered VBS is not described by an XY-order parameter with Z{sub N} anisotropy close to these quantum phase transitions. Instead, we demonstrate that on the honeycomb lattice, the staggered VBS is more appropriately described as an O(3)- or CP(2)-order parameter with cubic anisotropy, while on the square lattice it is described by an O(4)- or CP(3)-order parameter.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Selective Stationary Phase for Solid-Phase Microextraction Analysis of Sarin (GB)

    SciTech Connect

    Harvey, Scott D.; Nelson, David A.; Wright, Bob W.; Grate, Jay W.

    2002-04-19

    A number of critical field applications require monitoring air samples for trace levels of chemical warfare agents. Solid-phase microextraction (SPME) is a convenient format to conduct these analyses. Measurements could be significantly improved if a SPME phase selective for nerve agents were substituted for nonselective polymers typically used (e.g.,polydimethylsiloxane). This paper evaluates a novel stationary phase, previously developed for methylphosphonate sensor applications, for use with SPME sampling. The phenol-based polymer, BSP3, was found to offer far higher selectivity toward sarin (GB) than polydimethylsiloxane due to a pronounced affinity toward the target analyte and a lower affinity toward hydrocarbons.

  20. Selective Stationary Phase for Solid-Phase Microextraction Analysis of Sarin (GB)

    SciTech Connect

    Harvey, Scott; Nelson, D. A.; Wright, Bob W.; Gates, J. W.

    2002-03-02

    A number of critical field applications require monitoring air samples for trace levels of chemical warfare agents. Solid-phase microextraction (SPME) is a convenient format to conduct these analyses. Measurements could be significantly improved if a SPME phase selective for nerve agents were substituted for nonselective polymers typically used (e.g., polydimethylsiloxane). This paper evaluates a novel stationary phase, previously developed for methylphosphonate sensor applications, for use with SPME sampling. The phenol-based polymer, BSP3, was found to offer far higher selectivity toward sarin (GB) than polydimethylsiloxane due to a pronounced affinity toward the target analyte and a lower affinity toward hydrocarbons.

  1. Kinetics of (beta)(right arrow)(delta) Solid-Solid Phase Transition of HMX

    SciTech Connect

    Weese, R K

    2000-09-01

    In order to calculate the kinetic parameters from DSC data, we have used the generally accepted methods of Bershtein [13]. We have calculated the rate constants for 4 temperatures and the activation energy based on the shift in the transition temperature, {beta} {yields} {delta} for HMX. The values of E{sub a} from this work is 402 kJ/mol compared to previous results by Brill [9] of 204 kJ/mol. Brill and associates measured the phase transition of HMX using FTIR, sodium chloride plates and silicon oil. Given the differences in technique between FTIR and DSC the results found in this work are reasonable. In this investigation a large sample set (16) proved to be statistically valid for the determinations of k. Linear regressions were performed, observed and good fits were obtained, for each temperature. The enthalpy determination of {Delta}H{sub o}, for the {beta} {yields} {delta} phase transition was reproducible with in 3 parts in 100 over the range of this experiment. Thus, the data derived from this experiment k, E{sub a}, and {Delta}H{sub o} are valid parameters for the solid-solid phase transition. Obtaining pure {beta} phase HMX was very important for this investigation. Related to the phase change is the particle size distribution and is presented in Figure 3. Compared to previous work on HMX, this study utilized very pure {beta} phase material. In addition, the particle size was controlled more rigorously at about 160 {micro}m, giving a more consistent result for {alpha}. Thus, these kinetic results should have less scatter than results with less control of HMX purity and particle size. The kinetic basis of the polymorphic conversion is due to the cohesive forces in the HMX crystal lattice [21]. The energy required to bring about change from chair to chair-chair conformation has been reported by Brill [21] as ring torsion and is essentially a normal mode of the molecule that requires about 4 kJ mol{sup -1}. For the purpose of this investigation the energy

  2. Solid phase extraction of food contaminants using molecular imprinted polymers.

    PubMed

    Baggiani, Claudio; Anfossi, Laura; Giovannoli, Cristina

    2007-05-15

    Food contamination from natural or anthropogenic sources poses severe risks to human health. It is now largely accepted that continuous exposure to low doses of toxic chemicals can be related to several chronic diseases, including some type of cancer and serious hormonal dysfunctions. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but direct application of these methods on food samples can be rarely performed. In fact, the matrix introduces severe disturbances, and analysis can be performed only after some clean-up and preconcentration steps. Current sample pre-treatment methods, mostly based on the solid phase extraction technique, are very fast and inexpensive but show a lack of selectivity, while methods based on immunoaffinity extraction are very selective but expensive and not suitable for harsh environments. Thus, inexpensive, rapid and selective clean-up methods, relaying on "intelligent" materials are needed. Recent years have seen a significant increase of the "molecularly imprinted solid phase extraction" (MISPE) technique in the food contaminant analysis. In fact, this technique seems to be particularly suitable for extractive applications where analyte selectivity in the presence of very complex and structured matrices represents the main problem. In this review, several applications of MISPE in food contamination analysis will be discussed, with particular emphasis on the extraction of pesticides, drugs residua, mycotoxins and environmental contaminants. PMID:17456421

  3. Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy

    PubMed Central

    Zhou, Shengqiang; Liu, Fang; Prucnal, S.; Gao, Kun; Khalid, M.; Baehtz, C.; Posselt, M.; Skorupa, W.; Helm, M.

    2015-01-01

    Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping of chalcogen into the silicon matrix. However, this method encounters the problem of surface segregation. In this paper, we propose a solid phase processing by flash-lamp annealing in the millisecond range, which is in between the conventional rapid thermal annealing and pulsed laser annealing. Flash lamp annealed selenium-implanted silicon shows a substitutional fraction of ~ 70% with an implanted concentration up to 2.3%. The resistivity is lower and the carrier mobility is higher than those of nanosecond pulsed laser annealed samples. Our results show that flash-lamp annealing is superior to laser annealing in preventing surface segregation and in allowing scalability. PMID:25660096

  4. Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy.

    PubMed

    Zhou, Shengqiang; Liu, Fang; Prucnal, S; Gao, Kun; Khalid, M; Baehtz, C; Posselt, M; Skorupa, W; Helm, M

    2015-01-01

    Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping of chalcogen into the silicon matrix. However, this method encounters the problem of surface segregation. In this paper, we propose a solid phase processing by flash-lamp annealing in the millisecond range, which is in between the conventional rapid thermal annealing and pulsed laser annealing. Flash lamp annealed selenium-implanted silicon shows a substitutional fraction of ~ 70% with an implanted concentration up to 2.3%. The resistivity is lower and the carrier mobility is higher than those of nanosecond pulsed laser annealed samples. Our results show that flash-lamp annealing is superior to laser annealing in preventing surface segregation and in allowing scalability. PMID:25660096

  5. Effects of sample homogenization on solid phase sediment toxicity

    SciTech Connect

    Anderson, B.S.; Hunt, J.W.; Newman, J.W.; Tjeerdema, R.S.; Fairey, W.R.; Stephenson, M.D.; Puckett, H.M.; Taberski, K.M.

    1995-12-31

    Sediment toxicity is typically assessed using homogenized surficial sediment samples. It has been recognized that homogenization alters sediment integrity and may result in changes in chemical bioavailability through oxidation-reduction or other chemical processes. In this study, intact (unhomogenized) sediment cores were taken from a Van Veen grab sampler and tested concurrently with sediment homogenate from the same sample in order to investigate the effect of homogenization on toxicity. Two different solid-phase toxicity test protocols were used for these comparisons. Results of amphipod exposures to samples from San Francisco Bay indicated minimal difference between intact and homogenized samples. Mean amphipod survival in intact cores relative to homogenates was similar at two contaminated sites. Mean survival was 34 and 33% in intact and homogenized samples, respectively, at Castro Cove. Mean survival was 41% and 57%, respectively, in intact and homogenized samples from Islais Creek. Studies using the sea urchin development protocol, modified for testing at the sediment/water interface, indicated considerably more toxicity in intact samples relative to homogenized samples from San Diego Bay. Measures of metal flux into the overlying water demonstrated greater flux of metals from the intact samples. Zinc flux was five times greater, and copper flux was twice as great in some intact samples relative to homogenates. Future experiments will compare flux of metals and organic compounds in intact and homogenized sediments to further evaluate the efficacy of using intact cores for solid phase toxicity assessment.

  6. Solid Phase Characterization of Tank 241-C-108 Residual Waste Solids Samples

    SciTech Connect

    Cooke, Gary A.; Pestovich, John A.; Huber, Heinz J.

    2013-05-29

    This report presents the results for solid phase characterization (SPC) of solid samples removed from tank 241-C-108 (C-108) on August 12-13,2012, using the off-riser sampler. Samples were received at the 222-S Laboratory on August 13 and were described and photographed. The SPC analyses that were performed include scanning electron microscopy (SEM) using the ASPEX(R)l scanning electron microscope, X-ray diffraction (XRD) using the Rigaku(R) 2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon(R) 3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted the SEM analysis, John A. Pestovich performed the XRD analysis, and Dr. Heinz J. Huber performed the PLM examination. The results of these analyses are presented here.

  7. Studies of phase transitions in the aripiprazole solid dosage form.

    PubMed

    Łaszcz, Marta; Witkowska, Anna

    2016-01-01

    Studies of the phase transitions in an active substance contained in a solid dosage form are very complicated but essential, especially if an active substance is classified as a BCS Class IV drug. The purpose of this work was the development of sensitive methods for the detection of the phase transitions in the aripiprazole tablets containing initially its form III. Aripiprazole exhibits polymorphism and pseudopolymorphism. Powder diffraction, Raman spectroscopy and differential scanning calorimetry methods were developed for the detection of the polymorphic transition between forms III and I as well as the phase transition of form III into aripiprazole monohydrate in tablets. The study involved the initial 10 mg and 30 mg tablets, as well as those stored in Al/Al blisters, a triplex blister pack and HDPE bottles (with and without desiccant) under accelerated and long term conditions. The polymorphic transition was not observed in the initial and stored tablets but it was visible on the DSC curve of the Abilify(®) 10 mg reference tablets. The formation of the monohydrate was observed in the diffractograms and Raman spectra in the tablets stored under accelerated conditions. The monohydrate phase was not detected in the tablets stored in the Al/Al blisters under long term conditions. The results showed that the Al/Al blisters can be recommended as the packaging of the aripiprazole tablets containing form III. PMID:26397209

  8. Novel non-PEG derived polyethers as solid supports. 2. Solid-phase synthesis studies.

    PubMed

    Cavalli, Gabriel; Shooter, Andrew G; Pears, David A; Wellings, Donald A; Gulzar, Saeed; Steinke, Joachim H G

    2007-01-01

    Novel non-PEG derived polyether resins, coined SLURPS (Superior Liquid Uptake Resins for Polymer-supported Synthesis), were studied for their performance in solid-phase synthesis. Novel amino functional resins, SLURPS-NH2, were prepared with a loading of up to 8.5 mmol/g and employed successfully in the solid-phase synthesis of Leu-Enkephalin. The peptide was obtained with the same purity when compared to its synthesis with commercial standard poly(dimethyl acrylamide) resins. Furthermore we show loading and cleavage of aromatic carboxylic acids in excellent yield. The advantageous solvent compatibility of our support was demonstrated through the biphasic dihydroxylation of alkenes with OsO4 in t-BuOH/water mixtures producing bound 1,2-diols and synthesis and removal of a bound oxime using ethanol/water mixtures both in excellent yields. Reactions were easily monitored by gel-phase NMR and FTIR. These results show that SLURPS are very well suited for organic transformations using highly polar solvent mixtures and reagents and at much higher loading levels than standard amphiphilic resins of similar solvent compatibility. PMID:17900168

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

    NASA Astrophysics Data System (ADS)

    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 =km 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 =km 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.

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

    PubMed

    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. PMID:26274309

  11. Ferrofluid-based dispersive solid phase extraction of palladium.

    PubMed

    Farahani, Malihe Davudabadi; Shemirani, Farzaneh; Gharehbaghi, Maysam

    2013-05-15

    A new mode of dispersive solid phase extraction based on ferrofluid has been developed. In this method, an appropriate amount of ferrofluid is injected rapidly into the aqueous sample by a syringe. Since the sorbent is highly dispersed in the aqueous phase, extraction can be achieved within a few seconds. The ferrofluid can be attracted by a magnet and no centrifugation step is needed for phase separation. Palladium was used as a model compound in the development and evaluation of the extraction procedure in combination with flame atomic absorption spectrometry. The experimental parameters (pH, DDTC concentration, type and concentration of eluent, the amount of adsorbent, extraction time, and the effect of interfering ions) were investigated in detail. Under the optimized conditions, the calibration graph was linear over the range of 1-100 μg L(-1) and relative standard deviation of 3.3% at 0.1 μg mL(-1) was obtained (n=7). The limit of detection and enrichment factor (EF) was obtained to be 0.35 μg L(-1) and 267, respectively. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 24.6 mg g(-1) for Pd(II). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results. PMID:23618148

  12. System for exchange of hydrogen between liquid and solid phases

    DOEpatents

    Reilly, J.J.; Grohse, E.W.; Johnson, J.R.; Winsche, W.E.

    1985-02-22

    The reversible reaction M + x/2 H/sub 2/ reversible MH/sub x/, wherein M is a reversible metal hydride former that forms a hydride MH/sub x/ in the presence of H/sub 2/, generally used to store and recall H/sub 2/, is found to proceed under an inert liquid, thereby reducing contamination, providing better temperature control, providing in situ mobility of the reactants, and increasing flexibility in process design. Thus, a slurry of particles of a metal hydride former with an inert solvent is subjected to a temperature and pressure controlled atmosphere containing H/sub 2/, to store hydrogen and to release previously stored hydrogen. The direction of the flow of the H/sub 2/ through the liquid is dependent upon the H/sub 2/ pressure in the gas phase at a given temperature. When the actual H/sub 2/ pressure is above the equilibrium absorption pressure of the respective hydride the reaction proceeds to the right, i.e., the metal hydride is formed and hydrogen is stored in the solid particle. When the actual pressure in the gas phase is below the equilibrium dissociation pressure of the respective hydride the reaction proceeds to the left, the metal hydride is decomposed and hydrogen is released into the gas phase.

  13. System for exchange of hydrogen between liquid and solid phases

    DOEpatents

    Reilly, James J.; Grohse, Edward W.; Johnson, John R.; Winsche, deceased, Warren E.

    1988-01-01

    The reversible reaction M+x/2 H.sub.2 .rarw..fwdarw.MH.sub.x, wherein M is a reversible metal hydride former that forms a hydride MH.sub.x in the presence of H.sub.2, generally used to store and recall H.sub.2, is found to proceed under an inert liquid, thereby reducing contamination, providing better temperature control, providing in situ mobility of the reactants, and increasing flexibility in process design. Thus, a slurry of particles of a metal hydride former with an inert solvent is subjected to a temperature and pressure controlled atmosphere containing H.sub.2, to store hydrogen and to release previously stored hydrogen. The direction of the flow of the H.sub.2 through the liquid is dependent upon the H.sub.2 pressure in the gas phase at a given temperature. When the actual H.sub.2 pressure is above the equilibrium absorption pressure of the respective hydride the reaction proceeds to the right, i.e., the metal hydride is formed and hydrogen is stored in the solid particles. When the actual pressure in the gas phase is below the equilibrium dissociation pressure of the respective hydride the reaction proceeds to the left, the metal hydride is decomposed and hydrogen is released into the gas phase.

  14. Finite-temperature Wigner solid and other phases of ripplonic polarons on a helium film

    NASA Astrophysics Data System (ADS)

    Klimin, Serghei N.; Tempere, Jacques; Misko, Vyacheslav R.; Wouters, Michiel

    2016-07-01

    Electrons on liquid helium can form different phases depending on density, and temperature. Also the electron-ripplon coupling strength influences the phase diagram, through the formation of so-called "ripplonic polarons", that change how electrons are localized, and that shifts the transition between the Wigner solid and the liquid phase. We use an all-coupling, finite-temperature variational method to study the formation of a ripplopolaron Wigner solid on a liquid helium film for different regimes of the electron-ripplon coupling strength. In addition to the three known phases of the ripplopolaron system (electron Wigner solid, polaron Wigner solid, and electron fluid), we define and identify a fourth distinct phase, the ripplopolaron liquid. We analyse the transitions between these four phases and calculate the corresponding phase diagrams. This reveals a reentrant melting of the electron solid as a function of temperature. The calculated regions of existence of the Wigner solid are in agreement with recent experimental data.

  15. Nanoscale doping of compound semiconductors by solid phase dopant diffusion

    NASA Astrophysics Data System (ADS)

    Ahn, Jaehyun; Chou, Harry; Koh, Donghyi; Kim, Taegon; Roy, Anupam; Song, Jonghan; Banerjee, Sanjay K.

    2016-03-01

    Achieving damage-free, uniform, abrupt, ultra-shallow junctions while simultaneously controlling the doping concentration on the nanoscale is an ongoing challenge to the scaling down of electronic device dimensions. Here, we demonstrate a simple method of effectively doping ΙΙΙ-V compound semiconductors, specifically InGaAs, by a solid phase doping source. This method is based on the in-diffusion of oxygen and/or silicon from a deposited non-stoichiometric silicon dioxide (SiOx) film on InGaAs, which then acts as donors upon activation by annealing. The dopant profile and concentration can be controlled by the deposited film thickness and thermal annealing parameters, giving active carrier concentration of 1.4 × 1018 cm-3. Our results also indicate that conventional silicon based processes must be carefully reviewed for compound semiconductor device fabrication to prevent unintended doping.

  16. Solid-phase genotoxicity assay for organic compounds in soil

    SciTech Connect

    Alexander, R.R.; Chung, N.; Alexander, M.

    1999-03-01

    A genotoxicity assay was developed for samples from environments in which toxic organic compounds are largely sorbed. The assay entails measurement of the rate of mutation of a strain of Pseudomonas putida to rifampicin resistance. The ratio of induced to spontaneous mutants was a function of the concentration of a test mutagen in soil. In studies of the utility of the assay in samples amended with 2-aminofluorene as a test mutagen, the ratio of induced to spontaneous mutants declined with time. The decline paralleled the disappearance of extractable 2-aminofluorene from the soil. The ratio of induced to spontaneous mutants also feel in four other soils with dissimilar properties. The authors suggest that this solid-phase assay is more appropriate for the estimation of genotoxicants sorbed in soil than assays involving extractants or suspensions of soil or sediment samples.

  17. Method for preparing a solid phase microextraction device using aerogel

    DOEpatents

    Miller, Fred S.; Andresen, Brian D.

    2006-10-24

    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  18. Synthesis of phytochelatins by the continuous flow solid phase procedure.

    PubMed

    Chen, Z; Hemmasi, B

    1993-11-01

    A nona- and an undecapeptide corresponding to phytochelatins with the general structure H-[gamma-Glu-Cys]n-Gly-OH were each synthesized by the continuous flow solid phase method using two different methodologies. Fmoc-amino acid derivatives were used as precursors, and two different H2N-POE-PS supports were employed. Different procedures were used to remove Acm protecting groups from Cys residues. In a second synthesis, Acm groups were removed before cleavage of the peptides from the polymer supports. The partially protected peptides of the first synthesis were purified by preparative HPLC. The purity and identity of all the synthesized peptides were verified by analytical HPLC and IS-MS and in some cases by amino acid analysis. PMID:8292265

  19. Porous protective solid phase micro-extractor sheath

    DOEpatents

    Andresen, Brian D.; Randich, Erik

    2005-03-29

    A porous protective sheath for active extraction media used in solid phase microextraction (SPME). The sheath permits exposure of the media to the environment without the necessity of extending a fragile coated fiber from a protective tube or needle. Subsequently, the sheath can pierce and seal with GC-MS septums, allowing direct injection of samples into inlet ports of analytical equipment. Use of the porous protective sheath, within which the active extraction media is contained, mitigates the problems of: 1) fiber breakage while the fiber is extended during sampling, 2) active media coating loss caused by physical contact of the bare fiber with the sampling environment; and 3) coating slough-off during fiber extension and retraction operations caused by rubbing action between the fiber and protective needle or tube.

  20. Municipal solid waste development phases: Evidence from EU27.

    PubMed

    Vujić, Goran; Gonzalez-Roof, Alvaro; Stanisavljević, Nemanja; Ragossnig, Arne M

    2015-12-01

    Many countries in the European Union (EU) have very developed waste management systems. Some of its members have managed to reduce their landfilled waste to values close to zero during the last decade. Thus, European Union legislation is very stringent regarding waste management for their members and candidate countries, too. This raises the following questions: Is it possible for developing and developed countries to comply with the European Union waste legislation, and under what conditions? How did waste management develop in relation to the economic development in the countries of the European Union? The correlation between waste management practices and economic development was analysed for 27 of the European Union Member States for the time period between 1995 and 2007. In addition, a regression analysis was performed to estimate landfilling of waste in relation to gross domestic product for every country. The results showed a strong correlation between the waste management variables and the gross domestic product of the EU27 members. The definition of the municipal solid waste management development phases followed a closer analysis of the relation between gross domestic product and landfilled waste. The municipal solid waste management phases are characterised by high landfilling rates at low gross domestic product levels, and landfilling rates near zero at high gross domestic product levels. Hence the results emphasize the importance of wider understanding of what is required for developing countries to comply with the European Union initiatives, and highlight the importance of allowing developing countries to make their own paths of waste management development. PMID:26574580

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

    SciTech Connect

    Dumont, P.J.

    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.

  2. Development of novel solid-phase protein formulations

    NASA Astrophysics Data System (ADS)

    Montalvo Ortiz, Brenda Liz

    Proteins are the next-generation drugs for the treatment of several diseases. However, the number of protein drugs is still limited due to the physical or chemical instability of proteins during processing, formulation, storage, and delivery. The formulation of proteins at the solid state has advantages over liquid state, such as improved stability during long-term storage and delivery and decreases transportation costs. In this dissertation, we developed new solid-phase protein formulations in which the integrity of the protein was not compromised. The long term goal of this research was to use these protein formulations to improve protein stability in drug delivery devices, such as poly(lactic-co-glycolic) acid (PLGA). The first solid-phase protein formulation developed in this investigation was named "glassification". We proposed glassification as an alternative protein dehydration technique to the common used one, lyophilization, because this last method involves a series of steps which are detrimental to protein structure and stability. The glassification method consisted on protein dehydration by the use of organic solvents. As a result of the glassification process a small (micrometer size range) protein solid bead was obtained. The proteins used to study the glassification process were lysozyme (LYS), alpha-chymotrypsin (CHYMO) and horseradish peroxidase (HRP). These studies revealed that the glassification process itself did not alter protein structure and the activity was preserved. Ethyl acetate was the most effective organic solvent for protein glassification because it led to the highest protein residual activity, no insoluble aggregate formation and is a relatively non-toxic solvent, which allow the incorporation of these protein microparticles in PLGA microspheres. The incorporation of spherical HRP microparticles into PLGA microspheres resulted in superior properties when compared with encapsulated lyophilized HRP powder, such as improved release

  3. Solid Phase Formylation of N-Terminus Peptides.

    PubMed

    Tornesello, Anna Lucia; Sanseverino, Marina; Buonaguro, Franco Maria

    2016-01-01

    Formylation of amino groups is a critical reaction involved in several biological processes including post-translational modification of histones. The addition of a formyl group (CHO) to the N-terminal end of a peptide chain generates biologically active molecules. N-formyl-peptides can be produced by different methods. We performed the N-formylation of two chemotactic hexapetides, Met1-Leu2-Lys3-Leu4-Ile5-Val6 and Met1-Met2-Tyr3-Ala4-Leu5-Phe6, carrying out the reaction directly on peptidyl-resin following pre-activation of formic acid with N,N-dicyclohexylcarbodiimmide (DCC) in liquid phase. The overnight incubation at 4 °C resulted in a significant increase in production yields of formylated peptides compared to the reaction performed at room temperature. The method is consistently effective, rapid, and inexpensive. Moreover, the synthetic strategy can be applied for the formylation of all primary amines at N-terminus of peptide chains or amino groups of lysine side-chains in solid phase. PMID:27271589

  4. Solid-phase glycan isolation for glycomics analysis

    PubMed Central

    Yang, Shuang; Zhang, Hui

    2013-01-01

    Glycosylation is one of the most significant protein PTMs. The biological activities of proteins are dramatically changed by the glycans associated with them. Thus, structural analysis of the glycans of glycoproteins in complex biological or clinical samples is critical in correlation with the functions of glycans with diseases. Profiling of glycans by HPLC-MS is a commonly used technique in analyzing glycan structures and quantifying their relative abundance in different biological systems. Methods relied on MS require isolation of glycans from negligible salts and other contaminant ions since salts and ions may interfere with the glycans, resulting in poor glycan ionization. To accomplish those objectives, glycan isolation and clean-up methods including SPE, liquid-phase extraction, chromatography, and electrophoresis have been developed. Traditionally, glycans are isolated from proteins or peptides using a combination of hydrophobic and hydrophilic columns: proteins and peptides remain on hydrophobic absorbent while glycans, salts, and other hydrophilic reagents are collected as flowthrough. The glycans in the flowthrough are then purified through graphite-activated carbon column by hydrophilic interaction LC. Yet, the drawback in these affinity-based approaches is nonspecific binding. As a result, chemical methods by hydrazide or oxime have been developed for solid-phase isolation of glycans with high specificity and yield. Combined with high-resolution MS, specific glycan isolation techniques provide tremendous potentials as useful tools for glycomics analysis. PMID:23090885

  5. Solid-solid phase transformations induced through cation exchange and strain in 2D heterostructured copper sulfide nanocrystals.

    PubMed

    Ha, Don-Hyung; Caldwell, Andrew H; Ward, Matthew J; Honrao, Shreyas; Mathew, Kiran; Hovden, Robert; Koker, Margaret K A; Muller, David A; Hennig, Richard G; Robinson, Richard D

    2014-12-10

    We demonstrate dual interface formation in nanocrystals (NCs) through cation exchange, creating epitaxial heterostructures within spherical NCs. The thickness of the inner-disk layer can be tuned to form two-dimensional (2D), single atomic layers (<1 nm). During the cation exchange reaction from copper sulfide to zinc sulfide (ZnS), we observe a solid-solid phase transformation of the copper sulfide phase in heterostructured NCs. As the cation exchange reaction is initiated, Cu ions replaced by Zn ions at the interfaces are accommodated in intrinsic Cu vacancy sites present in the initial roxbyite (Cu1.81S) phase of copper sulfide, inducing a full phase transition to djurleite (Cu1.94S)/low chalcocite (Cu2S), a more thermodynamically stable phase than roxbyite. As the reaction proceeds and reduces the size of the copper sulfide layer, the epitaxial strain at the interfaces between copper sulfide and ZnS increases and is maximized for a copper sulfide disk ∼ 5 nm thick. To minimize this strain energy, a second phase transformation occurs back to the roxbyite phase, which shares a similar sulfur sublattice to wurtzite ZnS. The observation of a solid-solid phase transformation in our unique heterostructured NCs provides a new pathway to control desired phases and an insight into the influence of cation exchange on nanoscale phase transitions in heterostructured materials. PMID:25337657

  6. Phase diagram of PZT solid solutions near the morphotropic phase boundary from first principles

    NASA Astrophysics Data System (ADS)

    Kornev, I.; Bellaiche, L.; Janolin, P.-E.; Dkhil, B.; Suard, E.

    2007-03-01

    A first-principles-derived scheme, that incorporates ferroelectric and antiferrodistortive degrees of freedom, is developed to study finite-temperature properties of Pb(Zr1-xTix)O3 solid solutions near its morphotropic phase boundary [1]. The use of this numerical technique (i) resolves controversies about the monoclinic ground-state for some Ti compositions, (ii) leads to the discovery of an overlooked phase, and (iii) yields three multiphase points, that are each associated with four phases. Additional neutron diffraction measurements strongly support some of these predictions. [1] Igor A. Kornev, L. Bellaiche, P.-E. Janolin, B. Dkhil, and E. Suard, Phys. Rev. Lett. 97, 157601 (2006) This work is supported by ONR grants N00014-04-1-0413, N00014-01-1-0600 and N00014-01-1-0365, by NSF grant DMR- 0404335, and by DOE grant DE-FG02-05ER46188.

  7. Size Dependence of a Temperature-Induced Solid-Solid Phase Transition in Copper(I) Sulfide

    SciTech Connect

    Rivest, Jessy B; Fong, Lam-Kiu; Jain, Prashant K; Toney, Michael F; Alivisatos, A Paul

    2011-07-24

    Determination of the phase diagrams for the nanocrystalline forms of materials is crucial for our understanding of nanostructures and the design of functional materials using nanoscale building blocks. The ability to study such transformations in nanomaterials with controlled shape offers further insight into transition mechanisms and the influence of particular facets. Here we present an investigation of the size-dependent, temperature-induced solid-solid phase transition in copper sulfide nanorods from low- to high-chalcocite. We find the transition temperature to be substantially reduced, with the high chalcocite phase appearing in the smallest nanocrystals at temperatures so low that they are typical of photovoltaic operation. Size dependence in phase trans- formations suggests the possibility of accessing morphologies that are not found in bulk solids at ambient conditions. These other- wise-inaccessible crystal phases could enable higher-performing materials in a range of applications, including sensing, switching, lighting, and photovoltaics.

  8. Phase field modeling of grain growth in porous polycrystalline solids

    NASA Astrophysics Data System (ADS)

    Ahmed, Karim E.

    The concurrent evolution of grain size and porosity in porous polycrystalline solids is a technically important problem. All the physical properties of such materials depend strongly on pore fraction and pore and grain sizes and distributions. Theoretical models for the pore-grain boundary interactions during grain growth usually employ restrictive, unrealistic assumptions on the pore and grain shapes and motions to render the problem tractable. However, these assumptions limit the models to be only of qualitative nature and hence cannot be used for predictions. This has motivated us to develop a novel phase field model to investigate the process of grain growth in porous polycrystalline solids. Based on a dynamical system of coupled Cahn-Hilliard and All en-Cahn equations, the model couples the curvature-driven grain boundary motion and the migration of pores via surface diffusion. As such, the model accounts for all possible interactions between the pore and grain boundary, which highly influence the grain growth kinetics. Through a formal asymptotic analysis, the current work demonstrates that the phase field model recovers the corresponding sharp-interface dynamics of the co-evolution of grain boundaries and pores; this analysis also fixes the model kinetic parameters in terms of real materials properties. The model was used to investigate the effect of porosity on the kinetics of grain growth in UO2 and CeO2 in 2D and 3D. It is shown that the model captures the phenomenon of pore breakaway often observed in experiments. Pores on three- and four- grain junctions were found to transform to edge pores (pores on two-grain junction) before complete separation. The simulations demonstrated that inhomogeneous distribution of pores and pore breakaway lead to abnormal grain growth. The simulations also showed that grain growth kinetics in these materials changes from boundary-controlled to pore-controlled as the amount of porosity increases. The kinetic growth

  9. Modeling the solid-liquid phase transition in saturated triglycerides

    NASA Astrophysics Data System (ADS)

    Pink, David A.; Hanna, Charles B.; Sandt, Christophe; MacDonald, Adam J.; MacEachern, Ronald; Corkery, Robert; Rousseau, Dérick

    2010-02-01

    We investigated theoretically two competing published scenarios for the melting transition of the triglyceride trilaurin (TL): those of (1) Corkery et al. [Langmuir 23, 7241 (2007)], in which the average state of each TL molecule in the liquid phase is a discotic "Y" conformer whose three chains are dynamically twisted, with an average angle of ˜120° between them, and those of (2) Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid-state conformation of the TL molecule in the liquid phase is a nematic h∗-conformer whose three chains are in a modified "chair" conformation. We developed two competing models for the two scenarios, in which TL molecules are in a nematic compact-chair (or "h") conformation, with extended, possibly all-trans, chains at low-temperatures, and in either a Y conformation or an h∗ conformation in the liquid state at temperatures higher than the phase-transition temperature, T∗=319 K. We defined an h-Y model as a realization of the proposal of Corkery et al. [Langmuir 23, 7241 (2007)], and explored its predictions by mapping it onto an Ising model in a temperature-dependent field, performing a mean-field approximation, and calculating the transition enthalpy ΔH. We found that the most plausible realization of the h-Y model, as applied to the solid-liquid phase transition in TL, and likely to all saturated triglycerides, gave a value of ΔH in reasonable agreement with the experiment. We then defined an alternative h-h∗ model as a realization of the proposal of Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid phase exhibits an average symmetry breaking similar to an h conformation, but with twisted chains, to see whether it could describe the TL phase transition. The h-h∗ model gave a value of ΔH that was too small by a factor of ˜3-4. We also predicted the temperature dependence of the 1132 cm-1 Raman band for both models, and performed measurements of the ratios of three TL Raman

  10. Solid Phase Microextraction for the Analysis of Nuclear Weapons

    SciTech Connect

    Chambers, D M

    2001-06-01

    This document is a compendium of answers to commonly asked questions about solid phase microextraction as it relates to the analysis of nuclear weapons. We have also included a glossary of terms associated with this analytical method as well as pertinent weapons engineering terminology. Microextraction is a new collection technique being developed to nonintrusively sample chemicals from weapon headspace gases for subsequent analysis. The chemicals that are being targeted outgas from the high explosives and other organic materials used in the weapon assembly. This technique is therefore a valuable tool to: (1) remotely detect and assess the aging of Lawrence Livermore National Laboratory (LLNL) and, in some cases, Sandia National Laboratory (SNL) organic materials; and (2) identify potential compatibility issues (i.e., materials interactions) that should be more carefully monitored during surveillance tear-downs. Microextraction is particularly attractive because of the practical constraints inherent to the weapon surveillance procedure. To remain transparent to other core surveillance activities and fall within nuclear safety guidelines, headspace analysis of the weapons requires a procedure that: (1) maintains ambient temperature conditions; (2) allows practical collection times of less than 20 min; (3) maintains the integrity of the weapon gas volume; (4) provides reproducible and quantitative results; and (5) can identify all possible targets.

  11. Quasi in situ observation of Si lateral solid phase epitaxy

    NASA Astrophysics Data System (ADS)

    Ueno, T.; Kawai, K.; Morisawa, T.; Hatano, T.; Imai, S.; Kaneko, S.; Ohdomari, I.

    A quasi in situ observation of Si lateral solid phase epitaxy (L-SPE) has been carried out by an anneal-and-observe technique using a transmission electron microscope (TEM). For this observation, 3 mm Ø Si discs, which were thinned physically and chemically, were cut from a non-heated sample which had been prepared by depositing an amorphous Si (a-Si) film on the patterned amorphous insulator substrate. For the L-SPE growth, the thin specimens were heated in a furnace. The same areas of the same sample were repeatedly observed after an additional heating process at each interval. The direct origin of the (111) facet formation during the L-SPE growth has been precisely revealed by this method. Polygrains due to the random nucleation from the a-Si/a-insulator interface have been found to obstruct further L-SPE growth, while the L-SPE growth continued in the adjacent polygrain-free regions. As a result of this non-uniform growth rate, the (111) facets which nucleated at the polygrains grew into V-shaped valleys and finally caused a zig-zag growth front.

  12. Self-Sputtering of Solid and Liquid Phase Tin

    NASA Astrophysics Data System (ADS)

    Coventry, M. D.; Tomchik, C. A.; Ruzic, D. N.

    2004-11-01

    The absolute self-sputtering yields of solid and liquid-phase Sn have been measured for incident ions with energies of 300 to 1000 eV at 45^o using the Ion-surface InterAction eXperiment (IIAX). A Sn divertor^1 would experience self-bombardment from redepositing Sn ions, and its use may be limited by a temperature-enhanced self-sputtering yield. Thus, an understanding of any temperature dependence is a key to predictive modeling of such a device. IIAX uses a Colutron^2 ion source to produce a velocity-filtered Sn^+ beam for sample irradiation. Experiments were carried out with sample temperatures ranging from room temperature to 380^oC. A quartz-crystal microbalance (QCM) monitors sputtering by direct collection of ejected and reflected material; background noise is removed using a reference crystal. VFTRIM^3, which cannot simulate temperature, was used for comparison to recorded data and for data analysis. Hybrid Molecular-Dynamic/Monte Carlo simulations which include temperature effects^4 were also investigated. [1] Brooks, J.N. Fus. Eng. Des. 60 (2002) 515-526. [2] Menzinger, M. and Wahlin, L. Rev. Sci. Instrum. 40 (1969) 102-105. [3] Ruzic, D.N. Nuc. Instrum. Meth. Phys. Res. 47 (1990) 118-125. [4] Allain, J.P., D.N. Ruzic, submitted to Nuc. Instrum. Meth. B, January 2004

  13. Characterizing solid phase ammonia toxicity in marine sediments

    SciTech Connect

    Ho, K.T.; Burgess, R.M.; Kuhn, A.

    1994-12-31

    The presence and toxicity of ammonia in sediments represents an interesting scientific and regulatory concern. From a scientific perspective, ammonia toxicity is largely pH dependent and easily detected under special exposure conditions. Regulating the concentration of ammonia is difficult because ammonia concentrations may be elevated by naturally occurring anaerobic sediment bacteria; however, these bacteria may be enhanced by excessive carbon inputs into a system. This presentation will demonstrate progress toward characterizing ammonia toxicity.in solid phase exposure. Toxicity tests were conducted using the mysid (Mysidopsis bahia) and the amphipod (Ampelisca abdita). Results from ammonia spiked and ammonia induced whole marine sediments demonstrate pH dependent toxicity under a graduated pH (7, 8 and 9) testing regime. Several metals (Cd, Cu, Ni, Pb and Zn) tested under the graduated pH testing regime showed varying toxicity patterns also as a function of pH. Other compounds, the toxicity of which are pH dependent will be discussed. In addition the results of testing with complex environmental sediments containing high ammonia concentrations and other contaminants will be reported.

  14. Phase I studies of porfiromycin (NSC--56410) in solid tumors.

    PubMed

    Grage, T B; Weiss, A J; Wilson, W; Reynolds, V

    1975-01-01

    Porfiromycin was given to a group of patients with a variety of solid tumors. Of 114 patients admitted to the study, 103 yielded evaluable data. The following dosage schedules were used to determine the toxicity of porfiromycin when given in multiple doses by intravenous injection: 0.2 mg/kg x 5 days, 0.3 mg/kg x 5 days, 0.35 mg/kg x 5 days, 0.4 mg/kg x 5 days, 0.24 mg/kg x 10 days and 0.6 mg/kg weekly. Toxic effects noted were mainly leukopenia, thrombocytopenia, and, when injected paravenously, local tissue necrosis. Biological effects were noted at all dosage levels and were more severe at the higher dosages. The data suggest that profiromycin administered intravenously at a dose of 0.35 mg/kg daily for 5 days results in moderate hermatological toxicity and clinical evaluation in a Phase II study at this dosage level is indicated. PMID:1177472

  15. Solid-Phase Synthesis of Oligodeoxynucleotide Analogs Containing Phosphorodithioate Linkages.

    PubMed

    Yang, Xianbin

    2016-01-01

    The oligodeoxynucleotide phosphorodithioate modification (PS2-ODN) uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphordiester backbone linkage. Like a natural phosphodiester ODN backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-ODNs are highly stable to nucleases and numerous in vitro assays have demonstrated their biological activity. For example, PS2-ODNs activated RNase H in vitro, strongly inhibited human immunodeficiency virus (HIV) reverse transcriptase, induced B-cell proliferation and differentiation, and bound to protein targets in the form of PS2-aptamers (thioaptamers). Thus, the interest in and promise of PS2-ODNs has spawned a variety of strategies for synthesizing, isolating, and characterizing this compounds. ODN-thiophosphoramidite monomers are commercially available from either AM Biotechnologies or Glen Research and this unit describes an effective methodology for solid-phase synthesis, deprotection, and purification of ODNs having PS2 internucleotide linkages. © 2016 by John Wiley & Sons, Inc. PMID:27584703

  16. Molecularly imprinted solid phase extraction of fluconazole from pharmaceutical formulations.

    PubMed

    Manzoor, S; Buffon, R; Rossi, A V

    2015-03-01

    This work encompasses a direct and coherent strategy to synthesise a molecularly imprinted polymer (MIP) capable of extracting fluconazole from its sample. The MIP was successfully prepared from methacrylic acid (functional monomer), ethyleneglycoldimethacrylate (crosslinker) and acetonitrile (porogenic solvent) in the presence of fluconazole as the template molecule through a non-covalent approach. The non-imprinted polymer (NIP) was prepared following the same synthetic scheme, but in the absence of the template. The data obtained from scanning electronic microscopy, infrared spectroscopy, thermogravimetric and nitrogen Brunauer-Emmett-Teller plot helped to elucidate the structural as well as the morphological characteristics of the MIP and NIP. The application of MIP as a sorbent was demonstrated by packing it in solid phase extraction cartridges to extract fluconazole from commercial capsule samples through an offline analytical procedure. The quantification of fluconazole was accomplished through UPLC-MS, which resulted in LOD≤1.63×10(-10) mM. Furthermore, a high percentage recovery of 91±10% (n=9) was obtained. The ability of the MIP for selective recognition of fluconazole was evaluated by comparison with the structural analogues, miconazole, tioconazole and secnidazole, resulting in percentage recoveries of 51, 35 and 32%, respectively. PMID:25618633

  17. Solid phase epitaxial regrowth of (100)GaAs

    SciTech Connect

    Almonte, M I

    1996-02-01

    This thesis showed that low temperature (250 C) SPE of stoichiometrically balanced ion implanted GaAs layers can yield good epitaxial recovery for doses near the amorphization threshold. For 250 C anneals, most of the regrowth occurred in the first 10 min. HRTEM revealed much lower stacking fault density in the co-implanted sample than in the As-only and Ga-only samples with comparable doses. After low temp annealing, the nonstoichiometric samples had a large number of residual defects. For higher dose implants, very high temperatures (700 C) were needed to remove residual defects for all samples. The stoichiometrically balanced layer did not regrow better than the Ga-only and As-only samples. The co-implanted sample exhibited a thinner amorphous layer and a room temperature (RT) annealing effect. The amorphous layer regrew about 5 nm, suggesting that stoichiometrically balanced amorphous layers can regrow even at RT. Mechanisms for solid phase crystallization in (100)GasAs is discussed: nucleation and growth of randomly oriented crystallites and SPE. These two mechanisms compete in compound semiconductors at much lower temperatures than in Si. For the low dose As-only and Ga-only samples with low-temp anneals, both mechanisms are active. For this amorphization threshold dose, crystallites remain in the amorphous layer for all as-implants. 250 C annealing showed recrystallization from the surface and bulk for these samples; for the co-implant, the mechanism is not evident.

  18. Automated solid-phase radiofluorination using polymer-supported phosphazenes.

    PubMed

    Mathiessen, Bente; Zhuravlev, Fedor

    2013-01-01

    The polymer supported phosphazene bases PS-P₂(tBu) and the novel PS-P₂(PEG) allowed for efficient extraction of [¹⁸F]F⁻ from proton irradiated [¹⁸O]H₂O and subsequent radiofluorination of a broad range of substrates directly on the resin. The highest radiochemical yields were obtained with aliphatic sulfonates (69%) and bromides (42%); the total radiosynthesis time was 35-45 min. The multivariate analysis showed that the radiochemical yields and purities were controlled by the resin load, reaction temperature, and column packing effects. The resins could be reused several times with the same or different substrates. The fully automated on-column radiofluorination methodology was applied to the radiosynthesis of the important PET radiotracers [¹⁸F]FLT and [¹⁸F]FDG. The latter was produced with 40% yield on a 120 GBq scale and passed GMP-regulated quality control required for commercial production of [1¹⁸F]FDG. The combination of compact form factor, simplicity of [¹⁸F]F⁻ recovery and processing, and column reusability can make solid phase radiofluorination an attractive radiochemistry platform for the emerging dose-on-demand instruments for bedside production of PET radiotracers. PMID:23999726

  19. Automated solid-phase peptide synthesis to obtain therapeutic peptides

    PubMed Central

    Mäde, Veronika; Els-Heindl, Sylvia

    2014-01-01

    Summary The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS) offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies. PMID:24991269

  20. Solid-phase microextraction of VOCs in water

    SciTech Connect

    Pratt, K.; Shirey, R.; Mani, V.

    1996-12-31

    The measurement of very low concentrations of organic compounds in the environment has been a subject of research for many years. Recently, the sample preparation in the analysis of aqueous samples has been achieved by solid phase microextraction (SPME). This method has been shown to be fast, inexpensive, solventless, portable and automatable. SPME has several advantages over conventional liquid-liquid extraction. SPME has been shown to be quantitative technique for volatile and semivolatile compounds from gaseous and liquid samples. The quantization by SPME is also linear over four orders of magnitude. As this method can reach a detection limit of 15 ppt (parts per trillion) for several compounds and can be easily automated, the analysis of volatile organic compounds (VOCs) in the environment, in particular, water samples, is highly advantageous by this method. This study will describe the analysis of volatile organics, BTEX, and halogenated organics in water. The lowest limit of detection, linearity, and other parameters will be discussed. The analysis of a soil sample taken near an oil storage tank for VOCs by SPME will be described. A comparison between different fibers (different types of coating materials and film thickness) using different columns will be described in this work.

  1. Determining the solid phases hosting arsenic in Mekong Delta sediments

    NASA Astrophysics Data System (ADS)

    Wucher, M.; Stuckey, J. W.; McCurdy, S.; Fendorf, S.

    2011-12-01

    The major river systems originating from the Himalaya deposit arsenic bearing sediment into the deltas of South and Southeast Asia. High rates of sediment and organic carbon deposition combined with frequent flooding leads to anaerobic processes that release arsenic into the pore-water. Arsenic concentrations in the groundwater of these sedimentary basins are often above the World Health Organization drinking water standard of 10 μg As L-1. As a result, 150 million people are at risk of chronic arsenic poisoning through water and rice consumption. The composition of the iron bearing phases hosting the arsenic in these deltaic sediments is poorly understood. Here we implemented a suite of selective chemical extractions to help constrain the types of arsenic bearing solid phases, which were complimented with synchrotron-based X-ray absorption spectroscopy and X-ray diffraction analyses to define the arsenic and iron mineralogy of the system. Sediment cores were collected in triplicate from a seasonally-inundated wetland in Cambodia at depths of 10, 50, 100, and 150 centimeters. We hypothesize that (i) arsenic will be predominantly associated with iron oxides, and (ii) the ratio of crystalline to amorphous iron oxides will increase with sediment depth (and age). We performed four selective extractions in parallel to quantify the various pools of arsenic. First, 1 M MgCl2 was used to extract electrostatically-bound arsenic (labile forms) from the sediment. Second, 1 M NaH2PO4 targeted strongly adsorbed arsenic. Third, 1 M HCl was used to liberated arsenic coprecipitated with amorphous Fe/Mn oxides, carbonates, and acid-volatile sulfides. Finally, a dithionite extraction was used to account for arsenic associated with reducible Fe/Mn oxides. Through this work, we identified the composition of the phases hosting arsenic at various depths through the soil profile, improving our understanding of how arsenic persists in the aquifer. In addition, defining the arsenic and

  2. The Iron-Iron Carbide Phase Diagram: A Practical Guide to Some Descriptive Solid State Chemistry.

    ERIC Educational Resources Information Center

    Long, Gary J.; Leighly, H. P., Jr.

    1982-01-01

    Discusses the solid state chemistry of iron and steel in terms of the iron-iron carbide phase diagram. Suggests that this is an excellent way of introducing the phase diagram (equilibrium diagram) to undergraduate students while at the same time introducing the descriptive solid state chemistry of iron and steel. (Author/JN)

  3. Rapid synthesis of oligodeoxyribonucleotides. IV. Improved solid phase synthesis of oligodeoxyribonucleotides through phosphotriester intermediates.

    PubMed Central

    Gait, M J; Singh, M; Sheppard, R C; Edge, M D; Greene, A R; Heathcliffe, G R; Atkinson, T C; Newton, C R; Markham, A F

    1980-01-01

    A phosphotriester solid phase method on a polyamide support has been used to prepare oligodeoxyribonucleotides up to 12 units long. Compared to solid phase phosphodiester synthesis the new methodology is quicker, more flexible and gives 10-60-fold better overall yields. PMID:7443540

  4. Estimating production and consumption of solid reactive Fe phases in marine sediments from concentration profiles

    EPA Science Inventory

    1D diffusion models may be used to estimate rates of production and consumption of dissolved metabolites in marine sediments, but are applied less often to the solid phase. Here we used a numerical inverse method to estimate solid phase Fe(III) and Fe(II) consumption and product...

  5. Manual Solid-Phase Peptide Synthesis of Metallocene-Peptide Bioconjugates

    ERIC Educational Resources Information Center

    Kirin, Srecko I.; Noor, Fozia; Metzler-Nolte, Nils; Mier, Walter

    2007-01-01

    A simple and relatively inexpensive procedure for preparing a biologically active peptide using solid phase peptide synthesis (SPPS) is described. Fourth-year undergraduate students have gained firsthand experience from the solid-phase synthesis techniques and they have become familiar with modern analytical techniques based on the particular…

  6. Solid-state retrodirective phased array concepts for microwave power transmission from Solar Power Satellite

    NASA Technical Reports Server (NTRS)

    Schroeder, K. G.; Petroff, I. K.

    1980-01-01

    Two prototype solid-state phased array systems concepts for potential use in the Solar Power Satellite are described. In both concepts, the beam is centered on the rectenna by means of phase conjugation of a pilot signal emanating from the ground. Also discussed is on-going solid-state amplifier development.

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

    SciTech Connect

    Ambrose, D.

    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.

  8. Porous, High Capacity Coatings for Solid Phase Microextraction by Sputtering.

    PubMed

    Diwan, Anubhav; Singh, Bhupinder; Roychowdhury, Tuhin; Yan, DanDan; Tedone, Laura; Nesterenko, Pavel N; Paull, Brett; Sevy, Eric T; Shellie, Robert A; Kaykhaii, Massoud; Linford, Matthew R

    2016-02-01

    We describe a new process for preparing porous solid phase microextraction (SPME) coatings by the sputtering of silicon onto silica fibers. The microstructure of these coatings is a function of the substrate geometry and mean free path of the silicon atoms, and the coating thickness is controlled by the sputtering time. Sputtered silicon structures on silica fibers were treated with piranha solution (a mixture of concd H2SO4 and 30% H2O2) to increase the concentration of silanol groups on their surfaces, and the nanostructures were silanized with octadecyldimethylmethoxysilane in the gas phase. The attachment of this hydrophobic ligand was confirmed by X-ray photoelectron spectroscopy and contact angle goniometry on model, planar silicon substrates. Sputtered silicon coatings adhered strongly to their surfaces, as they were able to pass the Scotch tape adhesion test. The extraction time and temperature for headspace extraction of mixtures of alkanes and alcohols on the sputtered fibers were optimized (5 min and 40 °C), and the extraction performances of SPME fibers with 1.0 or 2.0 μm of sputtered silicon were compared to those from a commercial 7 μm poly(dimethylsiloxane) (PDMS) fiber. For mixtures of alcohols, aldehydes, amines, and esters, the 2.0 μm sputtered silicon fiber yielded signals that were 3-9, 3-5, 2.5-4.5, and 1.5-2 times higher, respectively, than those of the commercial fiber. For the heavier alkanes (undecane-hexadecane), the 2.0 μm sputtered fiber yielded signals that were approximately 1.0-1.5 times higher than the commercial fiber. The sputtered fibers extracted low molecular weight analytes that were not detectable with the commercial fiber. The selectivity of the sputtered fibers appears to favor analytes that have both a hydrophobic component and hydrogen-bonding capabilities. No detectable carryover between runs was noted for the sputtered fibers. The repeatability (RSD%) for a fiber (n = 3) was less than 10% for all analytes tested

  9. Downsizing vacuum-assisted headspace solid phase microextraction.

    PubMed

    Psillakis, Elefteria; Yiantzi, Evangelia; Kalogerakis, Nicolas

    2013-07-26

    Recently, we proposed a new headspace solid-phase microextraction (HSSPME) procedure, termed vacuum-assisted HSSPME (Vac-HSSPME), where headspace sampling of 10mL aqueous sample volumes took place in 500 or 1000mL sample containers under vacuum conditions. In the present study, we downsized the extraction device to a 22mL modified sample vial and concluded that changes in the final total pressure of the pre-evacuated vial following sample introduction were sufficiently low to allow efficient Vac-HSSPME sampling. The downsized extraction device was used to extract five low molecular weight polycyclic aromatic hydrocarbons and several experimental parameters were controlled and optimized. For those compounds whose mass transfer resistance in the thin gas-film adjacent to the gas/sample interface controls evaporation rates, reducing the total pressure during HSSPME sampling dramatically enhanced extraction kinetics in the 22mL modified vial. Humidity was found to affect the amount of naphthalene (intermediate KH compound) extracted by the fiber at equilibrium as well as impair extraction of all analytes at elevated sampling temperatures. All the same, the high extraction efficiency and very good sensitivity achieved at room temperature and within short sampling times comprised the most important features of Vac-HSSPME in this downsized extraction device. Analytically, the developed method was found to yield linear calibration curves with limits of detection in the low ngL(-1) level and relative standard deviations ranging between 1.3 and 5.8%. Matrix was found not to affect extraction. PMID:23473517

  10. Ultrarapid mutation detection by multiplex, solid-phase chemical cleavage

    SciTech Connect

    Rowley, G.; Saad, S.; Giannelli, F.; Green, P.M.

    1995-12-10

    The chemical cleavage of mismatches in heteroduplexes formed by probe and test DNA detects and locates any sequence change in long DNA segments ({approximately}1.8 kb), and its efficiency has been well tested in the analysis of both average (e.g., coagulation factor IX) and large, complex genes (e.g., coagulation factor VIII and dystrophin). In the latter application RT/PCR products allow the examination of all essential sequences of the gene in a minimum number of reactions. We use two specific chemical reactants (hydroxylamine and osmium tetroxide) and piperidine cleavage of the above procedure to develop a very fast mutation screening method. This is based on: (1) 5{prime} or internal fluorescent labeling to allow concurrent screening of three to four DNA fragments and (2) solid-phase chemistry to use a microliter format and reduce the time required for the procedure, from amplification of sequence to gel loading inclusive, to one person-working-day. We test the two variations of the method, one entailing 5{prime} labeling of probe DNA and the other uniform labeling of both probe and target DNA, by detecting 114 known hemophilia B (coagulation factor IX) mutations and by analyzing 129 new patients. Uniform labeling of both probe and target DNA prior to formation of the heteroduplexes leads to almost twofold redundancy in the ability to detect mutations. Alternatively, the latter procedure may offer very efficient though less than 100% screening for sequence changes with only hydroxylamine. The full method with two chemical reactions (hydroxylamine and osmium tetroxide) should allow one person to screen with virtually 100% accuracy more than 300 kb of sequence in three ABI 373 gels in 1 day. 26 refs., 7 figs., 1 tab.

  11. Reconstruction of Porous Media with Multiple Solid Phases

    PubMed

    Losic; Thovert; Adler

    1997-02-15

    A process is proposed to generate three-dimensional multiphase porous media with fixed phase probabilities and an overall correlation function. By varying the parameters, a specific phase can be located either at the interface between two phases or within a single phase. When the interfacial phase has a relatively small probability, its shape can be chosen as granular or lamellar. The influence of a third phase on the macroscopic conductivity of a medium is illustrated. PMID:9056372

  12. Microwave spectroscopic observation of distinct electron solid phases in wide quantum wells.

    PubMed

    Hatke, A T; Liu, Yang; Magill, B A; Moon, B H; Engel, L W; Shayegan, M; Pfeiffer, L N; West, K W; Baldwin, K W

    2014-01-01

    In high magnetic fields, two-dimensional electron systems can form a number of phases in which interelectron repulsion plays the central role, since the kinetic energy is frozen out by Landau quantization. These phases include the well-known liquids of the fractional quantum Hall effect, as well as solid phases with broken spatial symmetry and crystalline order. Solids can occur at the low Landau-filling termination of the fractional quantum Hall effect series but also within integer quantum Hall effects. Here we present microwave spectroscopy studies of wide quantum wells that clearly reveal two distinct solid phases, hidden within what in d.c. transport would be the zero diagonal conductivity of an integer quantum-Hall-effect state. Explanation of these solids is not possible with the simple picture of a Wigner solid of ordinary (quasi) electrons or holes. PMID:24948190

  13. Materials research for passive solar systems: solid-state phase-change materials

    SciTech Connect

    Benson, D.K.; Webb, J.D.; Burrows, R.W.; McFadden, J.D.O.; Christensen, C.

    1985-03-01

    A set of solid-state phase-change materials is being evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol (C/sub 5/H/sub 12/O/sub 4/), pentaglycerinve (C/sub 5/H/sub 12/O/sub 3/), and neopentyl glycol (C/sub 5/H/sub 12/O/sub 2/). Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature betweeen 25/sup 0/C and 188/sup 0/C, and have latent heats of transformation between 20 and 70 cal/g. Transformation temperatures, specific heats, and latent heats of transformation have been measured for a number of these materials. Limited cyclic experiments suggest that the solid solutions are stable. These phase-change materials exhibit large amounts of undercooling; however, the addition of certain nucleating agents as particulate dispersions in the solid phase-change material greatly reduces this effect. Computer simulations suggest that the use of an optimized solid-state phase-change material in a Trombe wall could provide better performance than a concrete Trombe wall four times thicker and nine times heavier. Nevertheless, a higher cost of the phase-change materials (approx. =$0.70 per pound) is likely to limit their applicability in passive solar systems unless their performance can be significantly improved through further research.

  14. Characterization of interactions between soil solid phase and soil solution in the initial ecosystem development phase

    NASA Astrophysics Data System (ADS)

    Zimmermann, Claudia; Schaaf, Wolfgang

    2010-05-01

    In the initial phase of soil formation interactions between solid and liquid phases and processes like mineral weathering, formation of reactive surfaces and accumulation of organic matter play a decisive role in developing soil properties. As part of the Transregional Collaborative Research Centre (SFB/TRR 38) 'Patterns and processes of initial ecosystem development' in an artificial catchment, these interactions are studied at the catchment 'Chicken Creek' (Gerwin et al. 2009). To link the interactions between soil solid phase and soil solution at the micro-scale with observed processes at the catchment scale, microcosm experiments under controlled laboratory conditions were carried out. Main objectives were to determine the transformation processes of C and N from litter decomposition within the gaseous, liquid and solid phase, the interaction with mineral surfaces and its role for the establishment of biogeochemical cycles. The microcosm experiments were established in a climate chamber at constant 10 ° C. In total 48 soil columns (diameter: 14.4 cm; height: 30 cm) were filled with two different quaternary substrates (sand and loamy sand) representing the textural variation within the catchment at a bulk density of 1.4-1.5 g*cm-3. The columns were automatically irrigated four times a day with 6.6 ml each (corresponding to 600 mm*yr-1). The gaseous phase in the headspace of the microcosms was analysed continuously for CO2 and N2O contents. C and N transformation processes were studied using 13C and 15N labelled litter of two different plant species occurring at the catchment (Lotus corniculatus, Calamagrostis epigejos) that was incorporated into the microcosm surface. All treatments including a control ran with four replicates over a period of 40 weeks. Two additional microcosms act as pure litter controls where substrate was replaced by glass pearls. Litter and substrate were analysed before and after the experiment. Percolate was continuously collected and

  15. Crystallization and Phase Changes in Paracetamol from the Amorphous Solid to the Liquid Phase

    PubMed Central

    2014-01-01

    For the case of paracetamol, we show how terahertz time-domain spectroscopy can be used to characterize the solid and liquid phase dynamics. Heating of supercooled amorphous paracetamol from 295 K in a covered sample under vacuum leads to its crystallization at 330 K. First, form III is formed followed by the transformation of form III to form II at 375 K, to form I at 405 K, and finally melting is observed around 455 K. We discuss the difference between the featureless spectra of the supercooled liquid and its liquid melt. Lastly, we studied the onset of crystallization from the supercooled liquid in detail and quantified its kinetics based on the Avrami–Erofeev model. We determined an effective rate constant of k = 0.056 min–1 with a corresponding onset of crystallization at T = 329.5 K for a heating rate of 0.4 K min–1. PMID:24579729

  16. Crystallization and phase changes in paracetamol from the amorphous solid to the liquid phase.

    PubMed

    Sibik, Juraj; Sargent, Michael J; Franklin, Miriam; Zeitler, J Axel

    2014-04-01

    For the case of paracetamol, we show how terahertz time-domain spectroscopy can be used to characterize the solid and liquid phase dynamics. Heating of supercooled amorphous paracetamol from 295 K in a covered sample under vacuum leads to its crystallization at 330 K. First, form III is formed followed by the transformation of form III to form II at 375 K, to form I at 405 K, and finally melting is observed around 455 K. We discuss the difference between the featureless spectra of the supercooled liquid and its liquid melt. Lastly, we studied the onset of crystallization from the supercooled liquid in detail and quantified its kinetics based on the Avrami-Erofeev model. We determined an effective rate constant of k = 0.056 min(-1) with a corresponding onset of crystallization at T = 329.5 K for a heating rate of 0.4 K min(-1). PMID:24579729

  17. Quantitative characterization of solid state phases by secondary neutral mass spectrometry

    NASA Astrophysics Data System (ADS)

    Oechsner, H.; Getto, R.; Kopnarski, M.

    2009-03-01

    The quantitative determination of chemical solid phases by secondary neutral mass spectrometry (SNMS) based on the quantitative character of this technique is described and demonstrated for several thin film structures. The intermetallic phases in a Ni-Zn coating on Fe are shown to be achieved directly from the concentration ratios determined by SNMS. When correlating the local elemental concentration tupels with the corresponding phase fractions by a matrix equation, the determination of chemical solid phase depth profiles becomes possible. This is exemplified by the detection of temperature induced chemical phases in Ni and Ti/Si films on SiC substrates.

  18. The Double Solid Reactant Method for modeling the release of trace elements from dissolving solid phases: I. Outline and limitations

    NASA Astrophysics Data System (ADS)

    Accornero, Marina; Marini, Luigi

    2008-10-01

    A Double Solid Reactant Method was elaborated from a suggestion of Marini (Geological sequestration of carbon dioxide: Thermodynamics, kinetics, and reaction path modeling. Developments in Geochemistry, Elsevier, Amsterdam, 2007) to simulate the release of trace elements during the progressive dissolution of solid phases. The method is based on the definition, for each dissolving solid, of both an entity whose thermodynamic and kinetic properties are known (either a pure mineral or a solid mixture) and a special reactant, that is, a material of known stoichiometry and unknown thermodynamic and kinetic properties. The special reactant is utilised to take into account the concentrations of trace elements in the dissolving solid phase. In this communication, the influence of several trace elements on the Δ G f o, Δ G r o and log K of the minerals considered by Lelli et al. (Environ Geol, 2007) and Accornero and Marini (Geobasi, 2007a; Proceedings of IMWA symposium, Cagliari, 27 31 May 2007b) was evaluated assuming ideal mixing in the solid state. These effects were found to be negligible for albite and the leucite latitic glass, limited for muscovites and chlorites, and slightly more important for apatites. These influences become progressively higher with increasing concentration of trace elements in these minerals. Based on these deviations in thermodynamic parameters, special reactants should not include oxide components with molar fractions higher than 0.003.

  19. Ultrasonic detection of solid phase mass flow ratio of pneumatic conveying fly ash

    NASA Astrophysics Data System (ADS)

    Duan, Guang Bin; Pan, Hong Li; Wang, Yong; Liu, Zong Ming

    2014-04-01

    In this paper, ultrasonic attenuation detection and weight balance are adopted to evaluate the solid mass ratio in this paper. Fly ash is transported on the up extraction fluidization pneumatic conveying workbench. In the ultrasonic test. McClements model and Bouguer-Lambert-Beer law model were applied to formulate the ultrasonic attenuation properties of gas-solid flow, which can give the solid mass ratio. While in the method of weigh balance, the averaged mass addition per second can reveal the solids mass flow ratio. By contrast these two solid phase mass ratio detection methods, we can know, the relative error is less.

  20. α-Azido Acids in Solid-Phase Peptide Synthesis: Compatibility with Fmoc Chemistry and an Alternative Approach to the Solid Phase Synthesis of Daptomycin Analogs.

    PubMed

    Lohani, Chuda Raj; Rasera, Benjamin; Scott, Bradley; Palmer, Michael; Taylor, Scott D

    2016-03-18

    α-Azido acids have been used in solid phase peptide synthesis (SPPS) for almost 20 years. Here we report that peptides bearing an N-terminal α-azidoaspartate residue undergo elimination of an azide ion when treated with reagents that are commonly used for removing the Fmoc group during SPPS. We also report an alternative solid-phase route to the synthesis of an analog of daptomycin that uses a reduced number of α-azido amino acids and without elimination of an azide ion. PMID:26938305

  1. Anomalous bond length behavior and a new solid phase of bromine under pressure

    PubMed Central

    Wu, Min; Tse, John S.; Pan, Yuanming

    2016-01-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases. PMID:27156710

  2. Anomalous bond length behavior and a new solid phase of bromine under pressure.

    PubMed

    Wu, Min; Tse, John S; Pan, Yuanming

    2016-01-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases. PMID:27156710

  3. Anomalous bond length behavior and a new solid phase of bromine under pressure

    NASA Astrophysics Data System (ADS)

    Wu, Min; Tse, John S.; Pan, Yuanming

    2016-05-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases.

  4. Solid-liquid phase equilibrium for binary Lennard-Jones mixtures

    NASA Astrophysics Data System (ADS)

    Hitchcock, Monica R.; Hall, Carol K.

    1999-06-01

    Solid-liquid phase diagrams are calculated for binary mixtures of Lennard-Jones spheres using Monte Carlo simulation and the Gibbs-Duhem integration technique of Kofke. We calculate solid-liquid phase diagrams for the model Lennard-Jones mixtures: argon-methane, krypton-methane, and argon-krypton, and compare our simulation results with experimental data and with Cottin and Monson's recent cell theory predictions. The Lennard-Jones model simulation results and the cell theory predictions show qualitative agreement with the experimental phase diagrams. One of the mixtures, argon-krypton, has a different phase diagram than its hard-sphere counterpart, suggesting that attractive interactions are an important consideration in determining solid-liquid phase behavior. We then systematically explore Lennard-Jones parameter space to investigate how solid-liquid phase diagrams change as a function of the Lennard-Jones diameter ratio, σ11/σ22, and well-depth ratio, ɛ11/ɛ22. This culminates in an estimate of the boundaries separating the regions of solid solution, azeotrope, and eutectic solid-liquid phase behavior in the space spanned by σ11/σ22 and ɛ11/ɛ22 for the case σ11/σ22<0.85.

  5. Solid concentration measurements in a three-phase slurry reactor by an ultrasonic technique

    SciTech Connect

    Soong, Y.; Blackwell, A.G.; Schehl, R.R.; Zarochak, M.F.

    1993-12-31

    This paper reports on the status of the development of an ultrasonic technique to measure the solid concentrations in a three-phase slurry reactor. Preliminary ultrasonic measurements have been made on slurries consisting of water, glass beads, and air bubbles. The data show that both the sound speed and attenuation are well-defined functions of the solid concentration in the slurries. A correlation exists between the solid concentration and the changing of the ultrasonic signal.

  6. Polarization transfer solid-state NMR for studying surfactant phase behavior.

    PubMed

    Nowacka, Agnieszka; Mohr, Parveen Choudhary; Norrman, Jens; Martin, Rachel W; Topgaard, Daniel

    2010-11-16

    The phase behavior of amphiphiles, e.g., lipids and surfactants, at low water content is of great interest for many technical and pharmaceutical applications. When put in contact with air having a moderate relative humidity, amphiphiles often exhibit coexistence between solid and liquid crystalline phases, making their complete characterization difficult. This study describes a (13)C solid-state NMR technique for the investigation of amphiphile phase behavior in the water-poor regime. While the (13)C chemical shift is an indicator of molecular conformation, the (13)C signal intensities obtained with the CP and INEPT polarization transfer schemes yield information on molecular dynamics. A theoretical analysis incorporating the effect of molecular segment reorientation, with the correlation time τ(c) and order parameter S, shows that INEPT is most efficient for mobile segments with τ(c) < 0.01 μs and S < 0.05, while CP yields maximal signal for rigid segments with τ(c) > 10 μs and/or S > 0.5 under typical solid-state NMR experimental conditions. For liquid crystalline phases, where τ(c) < 0.01 μs and 0 < S < 0.3, the observed CP and INEPT intensities serve as a gauge of S. The combination of information on molecular conformation and dynamics permits facile phase diagram determination for systems with solid crystalline, solid amorphous, anisotropic liquid crystalline, and isotropic liquid (crystalline) phases as demonstrated by experiments on a series of reference systems with known phase structure. Three solid phases (anhydrous crystal, dihydrate, gel), two anisotropic liquid crystalline phases (normal hexagonal, lamellar), and two isotropic liquid crystalline phases (micellar cubic, bicontinuous cubic) are identified in the temperature-composition phase diagram of the cetyltrimethylammonium succinate/water system. Replacing the succinate counterion with DNA prevents the formation of phases other than hexagonal and leads to a general increase of τ(c). PMID

  7. An immersed boundary-thermal lattice Boltzmann method for solid-liquid phase change

    NASA Astrophysics Data System (ADS)

    Huang, Rongzong; Wu, Huiying

    2014-11-01

    In this work, an immersed boundary-thermal lattice Boltzmann method (IB-TLBM) is proposed to simulate solid-liquid phase change problems. To treat the velocity and temperature boundary conditions on the solid-liquid interface, immersed boundary method (IBM) is adopted, in which the solid-liquid interface is represented as a sharp interface rather than a diffusive interface and is tracked explicitly by Lagrangian grid. The surface forces along the immersed boundary, including the “momentum force” for velocity boundary condition and the “energy force” for temperature boundary condition, are calculated by the direct-forcing scheme. The moving velocity of solid-liquid interface induced by phase change is calculated by the amount of latent heat absorbed or released in a time step directly, with no need to compute temperature gradients in solid and liquid phases separately. The temperature on the solid-liquid interface is specified as the melting temperature, which means phase change happens at a constant temperature. As the solid-liquid interface evolves with time, the identification of phase of Eulerian points and the rearrangement of Lagrangian points are also considered. With regard to the velocity and temperature fields, passive scalar thermal lattice Boltzmann method (TLBM) with multiple-relaxation-time (MRT) collision schemes is adopted. Numerical examples, including conduction-induced melting in a semi-infinite space and melting in a square cavity, are carried out to verify the present method and good results are obtained. As a further application, melting in a circular cylinder with considering the motion of solid phase is simulated successfully by the present method; numerical results show that the motion of solid phase accelerates the melting process obviously.

  8. COMPARING THE SOLID PHASE AND SALINE EXTRACT MICROTOX(R) ASSAYS FOR TWO PAH CONTAMINATED SOILS

    EPA Science Inventory

    The performance of remedial treatments is typically evaluated by measuring the concentration of specific chemicals. By adding toxicity bioassays to treatment evaluations, a fuller understanding of treatment performance is obtained. The solid phase Microtox assay is one potenti...

  9. DETERMINATION OF CHLOROETHENES IN ENVIRONMENTAL BIOLOGICAL SAMPLES USING GAS CHROMATOGRAPHY COUPLED WITH SOLID PHASE MICRO EXTRACTION

    EPA Science Inventory

    An analytical method has been developed to determine the chloroethene series, tetrachloroethene (PCE), trichloroethene (TCE),cisdichloroethene (cis-DCE) andtransdichloroethene (trans-DCE) in environmental biotreatment studies using gas chromatography coupled with a solid phase mi...

  10. COMPARATIVE YIELDS OF MUTAGENS FROM CIGARETTE SMOKERS' URINE OBTAINED BY USING SOLID-PHASE EXTRACTION TECHNIQUES

    EPA Science Inventory

    Urine from cigarette smokers was prepared for mutagenicity testing by extracting mutagens with solid phase extraction columns. ommercially available prepacked bonded silicas (cotadecyl, cyclohexyl, cyanopropyl) were compared for their efficiency and specificity in concentration o...

  11. EVALUATION OF SOLID PHASE MICROEXTRACTION FOR THE ANALYSIS OF HYDROPHILIC COMPOUNDS

    EPA Science Inventory

    Two commercially available solid phase microextractions (SPME) fibers, polyacrylate and carboxem/polydimethylsiloxane (PDMS), were evaluated for their ability to extract hydrophilic compounds from drinking water. Conditions, such as desorption time, desorption temperature, sample...

  12. Solid Phase Microextraction (SPME) Fibers for Preconcentration of Organics in Titan's Lakes

    NASA Astrophysics Data System (ADS)

    Hodyss, R.; Beauchamp, P. M.

    2012-10-01

    Solid phase microextraction (SPME) fibers are a simple and reliable means for extracting and concentrating organic trace species from liquid hydrocarbon solutions, making them an attractive approach for chemical analysis of Titan's lakes.

  13. A solid-state phase-insensitive ultrasonic transducer

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1979-01-01

    Photoconductive acoustoelectric transducer (AET) functions as phase-insensitive ultrasonic transducer. Device is easy to use and requires no additional noisy components such as light or thermal source.

  14. A new method for the measurement of solids holdup in gas-liquid-solid three-phase systems

    SciTech Connect

    Wenge, F.; Chisti, Y.; Moo-Young, M.

    1995-03-01

    Gas-liquid-solid multiphase systems are commonly encountered in the chemical process industry, in bio-processing, and in environmental pollution abatement devices. A method for the measurement of gas and solids holdups in gas-liquid-solid multiphase devices is developed and tested. The method depends on measurements of hydrostatic pressures in the three-phase dispersion followed by interruption of gas flow, complete gas disengagement, and a second pressure measurement in the resulting two-phase solid-liquid slurry, over a short period of time (< 30 s). The proposed method is compared with results obtained with physical sampling of the multiphase flow in vertical up- and down-flow in a large airlift reactor (0.243 m diameter, 7.825 m overall height, 2.44 riser-to-downcomer cross-sectional area ratio). Applicability of the technique to slurries of glass beads in tap water is demonstrated for various sizes and concentrations of beads over a range of gas flow rates (0.070--0.150 {times} 10{sup {minus}3} m bead diameter, 2,500 kg/m{sup 3} solids density, 0.02--0.17 m/s superficial gas velocity).

  15. Isotope effects in dense solid hydrogen - Phase transition in deuterium at 190 + or - 20 GPa

    NASA Technical Reports Server (NTRS)

    Hemley, R. J.; Mao, H. K.

    1989-01-01

    Raman measurements of solid normal deuterium compressed in a diamond-anvil cell indicate that the material undergoes a structural phase transformation at 190 + or - 20 GPa and 77 K. Spectroscopically, the transition appears analogous to that observed in hydrogen at 145 + or - 5 GPa. The large isotope effect on the transition pressure suggests there is a significant vibrational contribution to the relative stability of the solid phases of hydrogen at very high densities.

  16. Solid-Phase Synthesis of 1,3,7,8-Tetrasubstituted Xanthine Derivatives on Traceless Solid Support.

    PubMed

    Lee, Doohyun; Lee, Seungyeon; Liu, Kwang-Hyeon; Bae, Jong-Sup; Baek, Dong Jae; Lee, Taeho

    2016-01-11

    Traceless solid-phase synthesis of 1,3,7,8-tetrasubstituted xanthine (1,3,7,8-tetrasubstituted 1H-purine-2,6(3H,7H)-dione) derivatives has been developed. The solid-phase synthetic route began on a solid supported N'-cyano-N-substituted carbamimidothioate, which was prepared from cyanamide, isothiocyanate, and Merrifield resin. After N-alkylation of carbamimidothioate resin with ethyl 2-bromoacetate, an imidazole ring is introduced by Thorpe-Ziegler-type cyclization. The resulting imidazole resin is converted to 1,3,7-trisubstituted xanthine resin using sequential reactions, such as Lewis acid-catalyzed urea formation, pyrimidine ring cyclization, and N-alkylation. After oxidation of sulfides to sulfones, traceless cleavage with amine or thiol nucleophiles afforded the desired 1,3,7,8-tetrasubstituted xanthines in good purities and overall yields (eight-steps; 36 examples). This efficient solid-phase synthesis enables the incorporation of four diversity points into the preparation of the 1,3,7,8-tetrasubstituted xanthines. PMID:26616892

  17. New insights in Microbial Fuel Cells: novel solid phase anolyte.

    PubMed

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-01-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system. PMID:27375205

  18. Solid Phase Synthesis of C-Terminal Boronic Acid Peptides.

    PubMed

    Behnam, Mira A M; Sundermann, Tom R; Klein, Christian D

    2016-05-01

    Peptides and peptidomimetics with a C-terminal boronic acid group have prolific applications in numerous fields of research, but their synthetic accessibility remains problematic. A convenient, high yield synthesis of peptide-boronic acids on a solid support is described here, using commercially available 1-glycerol polystyrene resin. The method is compatible with Fmoc chemistry and offers a versatile approach to aryl and alkyl aminoboronic acids without additional purification steps. PMID:27104613

  19. New insights in Microbial Fuel Cells: novel solid phase anolyte

    NASA Astrophysics Data System (ADS)

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-07-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system.

  20. New insights in Microbial Fuel Cells: novel solid phase anolyte

    PubMed Central

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-01-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system. PMID:27375205

  1. Analysis of the structure of synthetic and natural melanins by solid-phase

    SciTech Connect

    Duff, G.A.; Roberts, J.E.; Foster, N.

    1988-09-06

    The structures of one synthetic and two natural melanins are examined by solid-state NMR using cross polarization, magic angle sample spinning, and high-power proton decoupling. The structural features of synthetic dopa malanin are compared to those of melanin from malignant melanoma cells grown in culture and sepia melanin from squid ink. Natural abundance /sup 13/C and /sup 15/N spectra show resonances consistent with known pyrrolic and indolic structures within the heterogeneous biopolymer; /sup 13/C spectra indicate the presence of aliphatic residues in all three materials. These solid-phase experiments illustrate the promise of solid-phase NMR for elucidating structural from insoluble biomaterials.

  2. Evaluation of phenylene-bridged periodic mesoporous organosilica as a stationary phase for solid phase extraction.

    PubMed

    Carpio, A; Esquivel, D; Arce, L; Romero-Salguero, F J; Van Der Voort, P; Jiménez-Sanchidrián, C; Válcarcel, M

    2014-11-28

    A periodic mesoporous organosilica, in particular, a phenylene-bridged material (Ph-PMO), was evaluated for the first time as a sorbent for retaining and eluting fenuron, simazine, atrazine, carbaryl and terbutryn in grape must by solid phase extraction (SPE) prior to their determination with capillary electrophoresis coupled with ultraviolet detection (CE-UV). The analytes were used as model compounds to demonstrate the potential of Ph-PMO for increasing the sensitivity of CE. Under optimal conditions, the limits of detection for the analytes ranged from 0.6 to 4 μg/L, and their limits of quantitation from 2 to 10 μg/L. These values were comparable and, in some cases, even better than those obtained with C18 and HLB materials. Ph-PMO was characterized physicochemically by X-ray diffraction analysis, N2 adsorption-desorption measurements and laser diffraction particle sizing. The sorbent afforded the extraction of atrazine, carbaryl and terbutryn from grape must with mean recoveries ranging from 86 to 105%. Therefore, periodic mesoporous organosilicas possess a high potential as SPE materials. PMID:25454127

  3. Research on the pattern of solid-liquid two-phase distribution in chemical process pump

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Jiang, Y.; Han, Z. J.

    2012-11-01

    In order to explore the pattern of solid-liquid two-phase flow distribution in first stage of double-suction impeller and the double volute channel of the HD type petrol-chemical process pump, the flow field in double-suction impeller and double volute is simulated with the CFD software, by taking the Reynolds Averaged Navier Stokes equations as its governing equations, and the standard k-ε model for turbulence, derives the pattern of solid particle concentration distribution in the impeller and double volute channel under different initial particle concentrations and different particle diameters. The results show that in the double-suction impeller, solid phase distribution changes a lot along with the increase of initial particle concentration; the concentration near the back side is higher than the face side. Solid particles have the motion trend to the back side of blade in double-suction impeller along with the increase of particle diameters. In double volute channel, solid phase concentration distribution is uneven and solid particle concentration is relatively higher from section 1 to section 8. In the diffusion section, concentration is high in lateral side and low in medial side, the solid particles have the motion trend to the lateral side and the solid particle concentration is relatively higher.

  4. Synthesis of gold-silica composite nanowires through solid-liquid-solid phase growth.

    PubMed

    Paulose, Maggie; Varghese, Oomman K; Grimes, Craig A

    2003-08-01

    Nanoscale wires of silicon oxide, and silicon oxide with embedded gold-silicide nanospheres, are synthesized by heating of a gold-coated silicon wafer at temperatures of 1000 degrees C or above, with the resulting wires having diameters ranging from 30 to 150 nm and lengths of approximately 1 mm. This simple fabrication process should make possible economical bulk production of nanowires. Studies indicate that the growth of these gold-silica composite nanowires occurs directly on the silicon wafer by a solid-liquid-solid mechanism. PMID:14598450

  5. Solid-matrix fluorescence and phosphorescence and solid-phase microextraction of polycyclic aromatic hydrocarbons with hydrophobic paper

    SciTech Connect

    Ackerman, A.H.; Hurtubise, R.J.

    1999-07-01

    Solid-matrix fluorescence (SMF) and solid-matrix phosphorescence (SMP) have been used in conjunction with solid-phase microextraction to characterize mixtures of polycyclic aromatic hydrocarbons (PAHs) isolated from water. Whatman 1PS paper was used to extract the PAH from water, and then the isolated PAHs were directly identified on the paper by obtaining SMF and SMP spectra. The SMF and SMP properties of 10 PAH were obtained, and the PAHs in a two-component mixture, a three-component mixture, and a four-component mixture were easily identified by a combination of SMF and SMP. No external heavy atom was needed to acquire the SMP data. Benzo[{ital e}]pyrene gave a limit of detection of 6.2 pg/mL with SMP, and with SMF benzo[{ital a}]pyrene gave a limit of detection of 19 pg/mL. {copyright} {ital 1999} {ital Society for Applied Spectroscopy}

  6. The solid state structures of the high and low temperature phases of dimethylcadmium.

    PubMed

    Hanke, Felix; Hindley, Sarah; Jones, Anthony C; Steiner, Alexander

    2016-08-01

    The solid state structure of dimethylcadmium, a classic organometallic compound with a long history, has remained elusive for almost a century. X-ray crystallography and density functional theory reveal similar phase behaviour as in dimethylzinc. The high temperature tetragonal phase, α-Me2Cd, exhibits two-dimensional disorder, while the low temperature monoclinic phase, β-Me2Cd, is ordered. Both phases contain linearly coordinated cadmium atoms. While the methyl groups are staggered in the α-phase, they are eclipsed in the β-phase. PMID:27457504

  7. Pulsed NMR in the nuclear spin ordered phases of solid 3He in a silver sinter

    NASA Astrophysics Data System (ADS)

    Millan-Chacartegui, Carmen; Schuberth, Erwin A.; Deppe, Frank; Schöttl, Stephan

    2003-05-01

    To obtain the exact spin structure of the nuclear magnetically ordered phases of solid 3He, in the BCC lattice called U2D2 and high field phase, both occurring below about 1 mK, we started a project of neutron scattering from the solid at the Hahn-Meitner Institut, Berlin. This experiment faces three main difficulties: to cool the solid to temperatures below 1 mK (or even much lower in the case of the HCP lattice), to keep it there under neutron flux, and to grow a single crystal within the sintered material needed for this purpose. As a first step we have performed pulsed NMR measurements in the ordered phases of solid 3He in a silver sinter of 700 Å particle size down to temperatures of 600 μK at various molar volumes. The samples remained in the ordered state for as long as 110 h.

  8. Application of nuclear techniques in two-phase liquid-solid particles hydrotransport investigations

    NASA Astrophysics Data System (ADS)

    Zych, Marcin; Hanus, Robert; Vlasak, Pavel; Petryka, Leszek; Jaszczur, Marek

    2016-03-01

    The paper presents gamma radiation application to two-phase flow investigation in a vertical pipeline, where the flow of solid particles transported by water was examined by use of both: radiotracers and gamma-absorption method. The simultaneous use of two methods allows analyzing of important parameters of solid particles hydrotransport. In the described experiments as solid phase the ceramic models representing natural polymetallic ocean nodules were used. Radiotracers allow to track the movements of selected models, representing specified grain size and the designation of its velocity. However gamma-absorption method enables measurement of average solid-phase velocity. For analysis of electrical signals obtained from scintillation detectors the cross-correlation method has been applied.

  9. Estrogenic and AhR activities in dissolved phase and suspended solids from wastewater treatment plants.

    PubMed

    Dagnino, Sonia; Gomez, Elena; Picot, Bernadette; Cavaillès, Vincent; Casellas, Claude; Balaguer, Patrick; Fenet, Hélène

    2010-05-15

    The distribution of estrogen receptor (ERalpha) and Aryl Hydrocarbon Receptor (AhR) activities between the dissolved phase and suspended solids were investigated during wastewater treatment. Three wastewater treatment plants with different treatment technologies (waste stabilization ponds (WSPs), trickling filters (TFs) and activated sludge supplemented with a biofilter system (ASB)) were sampled. Estrogenic and AhR activities were detected in both phases in influents and effluents. Estrogenic and AhR activities in wastewater influents ranged from 41.8 to 79 ng/L E(2) Eq. and from 37.9 to 115.5 ng/L TCDD Eq. in the dissolved phase and from 5.5 to 88.6 ng/g E(2) Eq. and from 15 to 700 ng/g TCDD Eq. in the suspended solids. For both activities, WSP showed greater or similar removal efficiency than ASB and both were much more efficient than TF which had the lowest removal efficiency. Moreover, our data indicate that the efficiency of removal of ER and AhR activities from the suspended solid phase was mainly due to removal of suspended solids. Indeed, ER and AhR activities were detected in the effluent suspended solid phase indicating that suspended solids, which are usually not considered in these types of studies, contribute to environmental contamination by endocrine disrupting compounds and should therefore be routinely assessed for a better estimation of the ER and AhR activities released in the environment. PMID:20303573

  10. Existence of Solutions for a Mathematical Model Related to Solid-Solid Phase Transitions in Shape Memory Alloys

    NASA Astrophysics Data System (ADS)

    Bonetti, Elena; Colli, Pierluigi; Fabrizio, Mauro; Gilardi, Gianni

    2016-01-01

    We consider a strongly nonlinear PDE system describing solid-solid phase transitions in shape memory alloys. The system accounts for the evolution of an order parameter χ (related to different symmetries of the crystal lattice in the phase configurations), of the stress (and the displacement u), and of the absolute temperature ϑ. The resulting equations present several technical difficulties to be tackled; in particular, we emphasize the presence of nonlinear coupling terms, higher order dissipative contributions, possibly multivalued operators. As for the evolution of temperature, a highly nonlinear parabolic equation has to be solved for a right hand side that is controlled only in L 1. We prove the existence of a solution for a regularized version by use of a time discretization technique. Then, we perform suitable a priori estimates which allow us pass to the limit and find a weak global-in-time solution to the system.

  11. Use of a solid-state multihead gamma counter in a second-generation system for solid-phase immunoassay

    SciTech Connect

    Parsons, G.H. Jr.; Rogers, C.H.; Polsky-Cynkin, R.; Wood, A.M.; Miles, L.E.; Rogers, A.H.

    1983-09-01

    Simultaneous advances in detector technology and solid-phase separation systems, as well as the availability of powerful desktop computers, have made possible the development of ''second-generation'' solid-phase immunoassays. These retain the advantages of classical solid phase while significantly accelerating reaction kinetics. Hapten assays--such as for digoxin, thyroxin, and triiodothyronine uptake--in batches of 48 are processed in about 20 min from reagent introduction until hard-copy printout, with minimal operator involvement. The system also functions as a 48-detector gamma counter, capable of counting and reducing data for any /sup 125/I-based RIA that can be run in a 12 X 75 mm test tube. System control, data management, and computer screen displays of kinetic data are provided by an unmodified Hewlett Packard HP-87XM computer. User-friendly disc-based software facilitates the creation and storage of counting and data reduction protocols for as many as 30 RIAs from various manufacturers as well as up to 30 of our own assays.

  12. Solid phase stability of molybdenum under compression: Sound velocity measurements and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Zhang, Xiulu; Liu, Zhongli; Jin, Ke; Xi, Feng; Yu, Yuying; Tan, Ye; Dai, Chengda; Cai, Lingcang

    2015-02-01

    The high-pressure solid phase stability of molybdenum (Mo) has been the center of a long-standing controversy on its high-pressure melting. In this work, experimental and theoretical researches have been conducted to check its solid phase stability under compression. First, we performed sound velocity measurements from 38 to 160 GPa using the two-stage light gas gun and explosive loading in backward- and forward-impact geometries, along with the high-precision velocity interferometry. From the sound velocities, we found no solid-solid phase transition in Mo before shock melting, which does not support the previous solid-solid phase transition conclusion inferred from the sharp drops of the longitudinal sound velocity [Hixson et al., Phys. Rev. Lett. 62, 637 (1989)]. Then, we searched its structures globally using the multi-algorithm collaborative crystal structure prediction technique combined with the density functional theory. By comparing the enthalpies of body centered cubic structure with those of the metastable structures, we found that bcc is the most stable structure in the range of 0-300 GPa. The present theoretical results together with previous ones greatly support our experimental conclusions.

  13. Solid phase stability of molybdenum under compression: Sound velocity measurements and first-principles calculations

    SciTech Connect

    Zhang, Xiulu; Liu, Zhongli; Jin, Ke; Xi, Feng; Yu, Yuying; Tan, Ye; Dai, Chengda; Cai, Lingcang

    2015-02-07

    The high-pressure solid phase stability of molybdenum (Mo) has been the center of a long-standing controversy on its high-pressure melting. In this work, experimental and theoretical researches have been conducted to check its solid phase stability under compression. First, we performed sound velocity measurements from 38 to 160 GPa using the two-stage light gas gun and explosive loading in backward- and forward-impact geometries, along with the high-precision velocity interferometry. From the sound velocities, we found no solid-solid phase transition in Mo before shock melting, which does not support the previous solid-solid phase transition conclusion inferred from the sharp drops of the longitudinal sound velocity [Hixson et al., Phys. Rev. Lett. 62, 637 (1989)]. Then, we searched its structures globally using the multi-algorithm collaborative crystal structure prediction technique combined with the density functional theory. By comparing the enthalpies of body centered cubic structure with those of the metastable structures, we found that bcc is the most stable structure in the range of 0–300 GPa. The present theoretical results together with previous ones greatly support our experimental conclusions.

  14. Thermoelastic properties of solid phases: C++ object oriented library “SolidEOS”

    NASA Astrophysics Data System (ADS)

    Churakov, Sergey V.

    2005-07-01

    A new object-oriented C++ library (SolidEOS) for calculating the thermoelastic properties of solids is presented. The implementation is based on the Mie-Grüneisen-Debye equation of state (EOS) augmented by lowest order correction for anharmonicity. Several commonly used static EOS like Birch-Murnaghan and Vinet models are available. Although some widely used approximation for the Debye-Grüneisen parameter and static EOS are implemented, the final behaviour of the EOS can be easily modified by overloading predefined virtual functions. The article provides a basic physical background of the modern theory of high-pressure EOS. The detailed documentation of the class hierarchy is summarized in the appendix, which accompanies the source. Several examples of practical use are given in the appendix as well. The library is appropriate for applications in geophysics, petrology, material science or any other field where thermodynamic and elastic properties of solids are relevant. The source code is available from the Computers & Geoscience software archive.

  15. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    SciTech Connect

    Lu, Xiaoyan E-mail: dzk@psu.edu; Li, Hui; Zheng, Limei; Cao, Wenwu

    2015-04-07

    Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr{sub 1−x}Ti{sub x})O{sub 3} system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point.

  16. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    PubMed

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-13

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization. PMID:26948023

  17. Solid phosphorus phase in aluminum- and iron-treated biosolids.

    PubMed

    Huang, Xiao-Lan; Chen, Yona; Shenker, Moshe

    2007-01-01

    Stabilization of phosphorus (P) in sewage sludge (biosolids) to reduce water-soluble P concentrations is essential for minimizing P loss from amended soils and maximizing the capacity of the soil to safely serve as an outlet for this waste material. The chemical form at which P is retained in biosolids stabilized by Al(2)(SO(4))(3) x 18H(2)O (alum) or FeSO(4) x 7H(2)O (FeSul) was investigated by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray elemental spectrometry (EDXS) and by X-ray diffraction (XRD). Both treatments resulted in the formation of a Ca-P phase, probably brushite. Phosphorus was further retained in the alum-treated biosolids by precipitation of an Al-P phase with an Al/P molar ratio of about 1:1, while in the FeSul-treated biosolids, P was retained by both precipitation with Fe/P molar ratios of 1:1 or 1.5:1, and by adsorption onto newly formed Fe hydroxides exhibiting an Fe/P molar ratio of up to 11:1. All of these mechanisms efficiently reduced P solubility and are crucial in biosolids environmentally safe agronomic beneficial use for this waste product; however, each P phase formed may react differently in the amended soil, depending on soil properties. Thus, the proper P stabilization method would depend on the target soil. PMID:17332259

  18. Enhanced denitrification of Pseudomonas stutzeri by a bioelectrochemical system assisted with solid-phase humin.

    PubMed

    Xiao, Zhixing; Awata, Takanori; Zhang, Dongdong; Zhang, Chunfang; Li, Zhiling; Katayama, Arata

    2016-07-01

    The denitrification reactions performed by Pseudomonas stutzeri JCM20778 were enhanced electrochemically with the use of solid-phase humin, although P. stutzeri itself was incapable of receiving electrons directly from the graphite electrode. Electrochemically reduced humin enhanced the microbial, but not abiotic, denitrification reactions. Electric current and cyclic voltammetry analyses suggested that the solid-phase humin functioned as an electron donor for the denitrification reactions of P. stutzeri. Nitrogen balance study and the estimation of the first-order rate constants of the consecutive denitrification reactions suggested that the solid-phase humin enhanced all reducing reactions from nitrate to nitrogen gas. Considering the wide distribution of humin in the environment, the findings that solid-phase humin can assist in electron transfer, from the electrode to a denitrifying bacterium that has little ability to directly utilize external electrons, has important implications for the widespread application of bioelectrochemical systems assisted by solid-phase humin for enhancing microbial denitrification. PMID:26905325

  19. Biogas production from municipal solid wastes using an integrated rotary drum and anaerobic-phased solids digester system.

    PubMed

    Zhu, Baoning; Zhang, Ruihong; Gikas, Petros; Rapport, Joshua; Jenkins, Bryan; Li, Xiujin

    2010-08-01

    This research was conducted to develop an integrated rotary drum reactor (RDR)-anaerobic-phased solids (APS) digester system for the treatment of municipal solid waste (MSW) to produce biogas energy and achieve waste reduction. A commercial RDR facility was used to provide a 3-d pretreatment and sufficient separation of the organics from MSW and then the organics were digested in a laboratory APS-digester system for biogas production. The organics generated from the RDR contained 50% total solids (TS) and 36% volatile solids (VS) on wet basis. The APS-digester was started at an organic loading rate (OLR) of 3.1 gVS L(-1) d(-1) and operated at three higher OLRs of 4.6, 7.7 and 9.2 gVS L(-1) d(-1). At the OLR of 9.2 gVS L(-1) d(-1) the system biogas production rate was 3.5 L L(-1) d(-1) and the biogas and methane yields were 0.38 and 0.19 L gVS(-1), respectively. Anaerobic digestion resulted in 38% TS reduction and 53% VS reduction in the organic solids. It was found that the total VFA concentration reached a peak value of 15,000 mg L(-1) as acetic acid in the first 3d of batch digestion and later decreased to about 500 mg L(-1). The APS-digester system remained stable at each OLRs for over 100d with the pH in the hydrolysis reactors in the range of 7.3-7.8 and the pH in the biogasification reactor in 7.9-8.1. The residual solids after the digestion had a high heating value of 14.7 kJ gTS(-1). PMID:20409703

  20. Fe-Solid Phase Transformations Under Highly Basic Conditions

    SciTech Connect

    Qafoku, Nik; Qafoku, Odeta; Ainsworth, Calvin C.; Dohnalkova, Alice; McKinley, Susan G.

    2007-09-01

    Hyperalkaline and saline radioactive waste fluids with elevated temperatures from S-SX high-level waste tank farm at Hanford, WA accidentally leaked into sediments beneath the tanks, initiating a series of geochemical processes and reactions whose significance and extent was unknown. Among the most important processes was the dissolution of soil minerals and precipitation of stable secondary phases. The objective of this investigation was to study the release of Fe into the aqueous phase upon dissolution of Fe-bearing soil minerals, and the subsequent formation of Fe rich precipitates. Batch reactors were used to conduct experiments at 50 0C using solutions similar in composition to the waste fluids. Results clearly showed that, similarly to Si and Al, Fe was released from the dissolution of soil minerals (most likely phyllosilicates such as biotite, smectite, and chlorite). The extent of Fe release increased with base concentration and decreased with Al concentration in the contacting solution. The maximum apparent rate of Fe release (0.566 × 10-13 mol m-2 s-1) was measured in the treatment with no Al and a concentration of 4.32 mol L-1 NaOH in the contacting solution. Results from electron microscopy indicated that while Si and Al precipitated together to form feldspathoids in the groups of cancrinite and/or sodalite, Fe precipitation followed a different pathway leading to the formation of hematite and goethite. The newly formed Fe oxy-hydroxides may increase the sorption capacity of the sediments, promote surface mediated reactions such as precipitation and heterogeneous redox reactions, and affect the phase distribution of contaminant and radionuclides.

  1. Solid phase sequencing of double-stranded nucleic acids

    DOEpatents

    Fu, Dong-Jing; Cantor, Charles R.; Koster, Hubert; Smith, Cassandra L.

    2002-01-01

    This invention relates to methods for detecting and sequencing of target double-stranded nucleic acid sequences, to nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probe comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Nucleic acids whose sequences can be determined include nucleic acids in biological samples such as patient biopsies and environmental samples. Probes may be fixed to a solid support such as a hybridization chip to facilitate automated determination of molecular weights and identification of the target sequence.

  2. Coupling phase transition kinetics and hydrodynamics: Models for solid-solid and liquid-solid transformation in dynamically driven materials

    NASA Astrophysics Data System (ADS)

    Belof, Jonathan; Benedict, Lorin; Chernov, Alexander; Hall, Burl; Hamel, Sebastien; Haxhimali, Tomorr; Sadigh, Babak; Zepeda-Ruiz, Luis

    High pressure and high strain-rate experiments are opening a new frontier toward the study of material science under extreme conditions. As the energy density of experimental platforms is increased, the timescale for observation is typically decreased to the point where the time dependence of phase transitions is now a subject of direct study. We will present new phase transition kinetics models that have been developed with unique considerations that arise in shock-wave driven phase transformation, highlighting applications of the methodology to the simulation of recent experiments of iron and water. This work is performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. Field recovery of explosive residues using solid-phase microextraction followed by chromatographic analysis

    NASA Astrophysics Data System (ADS)

    Almirall, Jose R.; Wu, Lianming; Bi, Grace; Shannon, Michael W.; Furton, Kenneth G.

    1999-02-01

    An inexpensive, rapid and sensitive method for the field pre-concentration and subsequent analysis of high explosive residues from solid debris samples and from aqueous samples has been evaluated using solid-phase microextraction. Explosives studied included nitrobenzene, 2-nitrotoluene, 3- nitrotoluene, 4-nitrotoluene, 2,6-dinitrotoluene, 1,3- dinitrobenzene, 2,4-dinitrotoluene, trinitrotoluene, 1,3,5- trinitrobenzene, 4-amino-2,6-dinitrotoluene, 2-amino-4,6- dinitrotolene and tetryl.

  4. Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

    PubMed

    Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko

    2016-04-01

    Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort. Graphical Abstract ᅟ. PMID:26879646

  5. Biological nitrate removal from water and wastewater by solid-phase denitrification process.

    PubMed

    Wang, Jianlong; Chu, Libing

    2016-11-01

    Nitrate pollution in receiving waters has become a serious issue worldwide. Solid-phase denitrification process is an emerging technology, which has received increasing attention in recent years. It uses biodegradable polymers as both the carbon source and biofilm carrier for denitrifying microorganisms. A vast array of natural and synthetic biopolymers, including woodchips, sawdust, straw, cotton, maize cobs, seaweed, bark, polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polybutylene succinate (PBS) and polylactic acid (PLA), have been widely used for denitrification due to their good performance, low cost and large available quantities. This paper presents an overview on the application of solid-phase denitrification in nitrate removal from drinking water, groundwater, aquaculture wastewater, the secondary effluent and wastewater with low C/N ratio. The types of solid carbon source, the influencing factors, the microbial community of biofilm attached on the biodegradable carriers, the potential adverse effect, and the cost of denitrification process are introduced and evaluated. Woodchips and polycaprolactone are the popular and competitive natural plant-like and synthetic biodegradable polymers used for denitrification, respectively. Most of the denitrifiers reported in solid-phase denitrification affiliated to the family Comamonadaceae in the class Betaproteobacteria. The members of genera Diaphorobacter, Acidovorax and Simplicispira were mostly reported. In future study, more attention should be paid to the simultaneous removal of nitrate and toxic organic contaminants such as pesticide and PPCPs by solid-phase denitrification, to the elucidation of the metabolic and regulatory relationship between decomposition of solid carbon source and denitrification, and to the post-treatment of the municipal secondary effluent. Solid-phase denitrification process is a promising technology for the removal of nitrate from water and wastewater. PMID:27396522

  6. Leaching behavior and solubility -- Controlling solid phases of heavy metals in municipal solid waste incinerator ash

    SciTech Connect

    Johnson, C.A.; Ziegler, F.; Kersten, M.; Moor, H.C.

    1996-12-31

    This paper highlights the uses and limitations of thermodynamic calculations in the planning of leach tests in the laboratory or for research in the field. Heavy metal solubility has been studied in leachate from Landfill Lostorf, AG, Switzerland. Also, the influence of pH on the solubility of Cu, Pb, Cd and Zn has been determined in the laboratory. The results have been compared with the maximum allowable heavy metal concentrations in equilibrium with the appropriate (hydr)oxides and carbonates. Copper is supersaturated with respect to Cu(OH){sub 2} in both laboratory and field studies. Complexation with organic ligands is a probable explanation for this observation. Both Zn and Pb are undersaturated with respect to pure (hydr)oxides and carbonates, though agreement between calculations and measurements are close enough, that PbCO{sub 3} could be controlling the solubility in the laboratory experiments. The markedly lower concentrations of Pb in the field in comparison with the laboratory data could be explained by the affinity for Pb to bind to solids and the higher solid:solution ratio in field conditions. The solubility of Cd could be controlled by the formation of CdCO{sub 3}. The relatively high concentrations of Mo in the landfill leachate could be limited by the precipitation of CaMoO{sub 4}.

  7. Performance evaluation of the phosphorescent porphyrin label: solid-phase immunoassay of alpha-fetoprotein.

    PubMed

    O'Riordan, Tomás C; Soini, Aleksi E; Soini, Juhani T; Papkovsky, Dmitri B

    2002-11-15

    Phosphorescent conjugates of antibodies, neutravidin, and biotin (pentylamine derivative) were synthesized using previously described monofunctional labeling reagent of platinum(II) coproporphyrin-I with isothiocyanate reactive group (PtCP-NCS). These conjugates, which can be considered as standard reagents for a range of bioanalytical applications, were evaluated in solid-phase immunoassay schemes with the clinical analyte a-fetoprotein (AFP). A custom-designed time-resolved phosphorescence plate reader based on a compact and low-cost 532-nm laser and optimized for measurement of porphyrin labels was used. Using optimized tracers, instrumentation and assay protocols, subpicomolar detection limits were obtained both for PtCP label in solution and for AFP in solid-phase immunoassay. This sensitivity is comparable with standard time-resolved fluorescence immunoassays with lanthanide labels. The performance of metalloporphyrin labels, instrumentation, and solid-phase immunoassays as an alternative to the established detection platforms is discussed. PMID:12463371

  8. The use of coal in a solid phase reduction of iron oxide

    NASA Astrophysics Data System (ADS)

    Nokhrina, O. I.; Rozhihina, I. D.; Hodosov, I. E.

    2015-09-01

    The results of the research process of producing metalized products by solid-phase reduction of iron using solid carbonaceous reducing agents. Thermodynamic modeling was carried out on the model of the unit the Fe-C-O and system with iron ore and coal. As a result of modeling the thermodynamic boundary reducing, oxidizing, and transition areas and the value of the ratio of carbon and oxygen in the system. Simulation of real systems carried out with the gas phase obtained in the pyrolys of coal. The simulation results allow to determine the optimal cost of coal required for complete reduction of iron ore from a given composition. The kinetics of the processes of solid-phase reduction of iron using coal of various technological brands.

  9. A scheme for a single molecule phase-shift gate in a solid matrix

    SciTech Connect

    Cui, Xiao-Dong; Zheng, Yujun

    2015-06-07

    We propose a feasible scheme to implement a phase-shift gate ( (table) ) based on a two-state single molecule in a solid matrix, where γ is a geometric phase controlled through a fast on-resonant laser field and a slow off-resonant radio-frequency field. In our scheme, a non-Hermitian quantum model is employed to characterize the single molecule in a solid matrix including the spontaneous decay effect. By the coupling between the radio-frequency field and the two-state permanent dipole difference resulting from the solid matrix, the spontaneous decay fatal to the preservation of geometric phase can be effectively suppressed for a considerably long waiting time.

  10. Solid-Phase Synthesis of Amine/Carboxyl Substituted Prolines and Proline Homologues: Scope and Limitations.

    PubMed

    Zhou, Ziniu; Scott, William L; O'Donnell, Martin J

    2016-01-01

    A solid-phase procedure is used to synthesize racemic peptidomimetics based on the fundamental peptide unit. The peptidomimetics are constructed around proline or proline homologues variably substituted at the amine and carbonyl sites. The procedure expands the diversity of substituted peptidomimetic molecules available to the Distributed Drug Discovery (D3) project. Using a BAL-based solid-phase synthetic sequence the proline or proline homologue subunit is both constructed and incorporated into the peptidomimetic by an α-alkylation, hydrolysis and intramolecular cyclization sequence. Further transformations on solid-phase provide access to a variety of piperazine derivatives representing a class of molecules known to exhibit central nervous system activity. The procedure works well with proline cores, but with larger six- and seven-membered ring homologues the nature of the carboxylic acid acylating the cyclic amine can lead to side reactions and result in poor overall yields. PMID:26999079

  11. NASA satellite communications application research. Phase 2: Efficient high power, solid state amplifier for EFH communications

    NASA Technical Reports Server (NTRS)

    Benet, James

    1993-01-01

    The final report describes the work performed from 9 Jun. 1992 to 31 Jul. 1993 on the NASA Satellite Communications Application Research (SCAR) Phase 2 program, Efficient High Power, Solid State Amplifier for EHF Communications. The purpose of the program was to demonstrate the feasibility of high-efficiency, high-power, EHF solid state amplifiers that are smaller, lighter, more efficient, and less costly than existing traveling wave tube (TWT) amplifiers by combining the output power from up to several hundred solid state amplifiers using a unique orthomode spatial power combiner (OSPC).

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

    ERIC Educational Resources Information Center

    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…

  13. Application of solid phase extraction procedures for rare earth elements determination in environmental samples.

    PubMed

    Pyrzynska, Krystyna; Kubiak, Anna; Wysocka, Irena

    2016-07-01

    Determination of rare earth elements in environmental samples requires often pre-concentration and separation step due to a low metal content and high concentration of the interfering matrix components. A solid phase extraction technique with different kind of solid sorbents offers a high enrichment factor, rapid phase separation and the possibility of its combination with various detection techniques used either in on-line or off-line mode. The recent developments in this area published over the last five years are presented and discussed in this paper. PMID:27154643

  14. Optical Measurement for Solid- and Liquid-Phase Sb2Te3 around Its Melting Point

    NASA Astrophysics Data System (ADS)

    Kuwahara, Masashi; Endo, Rie; Tsutsumi, Kouichi; Morikasa, Fukuyoshi; Tsuruoka, Tohru; Fukaya, Toshio; Suzuki, Michio; Susa, Masahiro; Endo, Tomoyoshi; Tadokoro, Toshiyasu

    2013-11-01

    We have developed a system for measuring the complex refractive index of liquid- and solid-phase chalcogenide around their melting points. The system consists of a spectroscopic ellipsometer, an infrared heating system, and prism optics. As a container for the chalcogenide, we use a customized quartz cell, evacuated to several pascal level to avoid sample degradation. We adopted a measurement configuration that uses access from the bottom side, because a mirror-like surface which is necessary for optical measurement was naturally and easily created at the container bottom by gravity. We succeeded in observing the remarkable difference on the indices between liquid- and solid-phase Sb2Te3.

  15. Solid-Phase Spectrophotometric Analysis of 1-Naphthol Using Silica Functionalized with m-Diazophenylarsonic Acid

    NASA Astrophysics Data System (ADS)

    Zaitseva, Nataliya; Alekseev, Sergei; Zaitsev, Vladimir; Raks, Viktoria

    2016-03-01

    The m-aminophenylarsonic acid (m-APAA) was immobilized onto the silica gel surface with covalently grafted quaternary ammonium groups via ion exchange. The diazotization of ion-bonded m-APAA resulted in a new solid-phase spectrophotometric reagent for detection of 1-naphtol in environmental water samples. The procedure of solid-phase spectrophotometric analysis is characterized by 20 μg L-1 limit of detection (LOD) of 1-naphtol, up to 2000 concentration factor, and insensitivity to the presence of natural water components as well as to 30-fold excess of phenol, resorcinol, and catechol.

  16. Automated extraction of acetylgestagens from kidney fat by matrix solid phase dispersion.

    PubMed

    Rosén, J; Hellenäs, K E; Törnqvist, P; Shearan, P

    1994-12-01

    A new extraction method for the acetylgestagens medroxyprogesterone acetate (MPA), chloromadinone acetate and megestrol acetate, from kidney fat, has been developed. The method is a combination of matrix solid phase dispersion and solid phase extraction and is simpler and safer than previous methods, especially as it can be automated. The recovery was estimated as 59 +/- 5% (mean +/- standard deviation) for MPA. For screening purposes detection can be achieved using a commercially available enzyme immunoassay kit giving detection limits in the range of 1.0-2.0 ng g-1. PMID:7533481

  17. Development of orthogonally protected hypusine for solid-phase peptide synthesis.

    PubMed

    Song, Aimin; Tom, Jeffrey; Yu, Zhiyong; Pham, Victoria; Tan, Dajin; Zhang, Dengxiong; Fang, Guoyong; Yu, Tao; Deshayes, Kurt

    2015-04-01

    An orthogonally protected hypusine reagent was developed for solid-phase synthesis of hypusinated peptides using the Fmoc/t-Bu protection strategy. The reagent was synthesized in an overall yield of 27% after seven steps from Cbz-Lys-OBzl and (R)-3-hydroxypyrrolidin-2-one. The side-chain protecting groups (Boc and t-Bu) are fully compatible with standard Fmoc chemistry and can be readily removed during the peptide cleavage step. The utility of the reagent was demonstrated by solid-phase synthesis of hypusinated peptides. PMID:25769022

  18. Solid-Phase Spectrophotometric Analysis of 1-Naphthol Using Silica Functionalized with m-Diazophenylarsonic Acid.

    PubMed

    Zaitseva, Nataliya; Alekseev, Sergei; Zaitsev, Vladimir; Raks, Viktoria

    2016-12-01

    The m-aminophenylarsonic acid (m-APAA) was immobilized onto the silica gel surface with covalently grafted quaternary ammonium groups via ion exchange. The diazotization of ion-bonded m-APAA resulted in a new solid-phase spectrophotometric reagent for detection of 1-naphtol in environmental water samples. The procedure of solid-phase spectrophotometric analysis is characterized by 20 μg L(-1) limit of detection (LOD) of 1-naphtol, up to 2000 concentration factor, and insensitivity to the presence of natural water components as well as to 30-fold excess of phenol, resorcinol, and catechol. PMID:26979727

  19. Selective enrichment of phenols from coal liquefaction oil by solid phase extraction method

    SciTech Connect

    Tian, M.; Feng, J.

    2009-07-01

    This study focuses on the solid phase extraction method for the enrichment and separation of phenol from coal liquefaction oil. The phenols' separation efficiency was compared on different solid phase extraction (SPE) cartridges, and the effect of solvents with different polarity and solubility parameter on amino-bonded silica was compared for selection of optimal elution solution. The result showed that amino-bonded silica has the highest selectivity and best extraction capability due to two factors, weak anion exchange adsorption and polar attraction adsorption.

  20. Synthesis of a Small Library of Imidazolidin-2-ones using Gold Catalysis on Solid Phase.

    PubMed

    La-Venia, Agustina; Medran, Noelia S; Krchňák, Viktor; Testero, Sebastián A

    2016-08-01

    An efficient and high-yielding solid phase synthesis of a small library of imidazolidin-2-ones and imidazol-2-ones was carried out employing a high chemo- and regioselective gold-catalyzed cycloisomerization as a key step. Polymer-supported amino acids derivatized with several alkyne functionalities combined with tosyl- and phenylureas have been subjected to gold-catalysis exhibiting exclusively C-N bond formation. The present work proves the potential of solid phase synthesis and homogeneous gold catalysis as an efficient and powerful synthetic tool for the generation of drug-like heterocycles. PMID:27337593

  1. Detection of ibuprofen and ciprofloxacin by solid-phase extraction and UV/Vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Zhengwei; Jiang, Jia Qian

    2012-07-01

    A simple and economic solid-phase extraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phase extraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.

  2. 2,6-Diketopiperazines from amino acids, from solution-phase to solid-phase organic synthesis.

    PubMed

    Perrotta, E; Altamura, M; Barani, T; Bindi, S; Giannotti, D; Harmat, N J; Nannicini, R; Maggi, C A

    2001-01-01

    A method to prepare 1,3-disubstituted 2,6-diketopiperazines (2,6-DKP) as useful heterocyclic library scaffolds in the search of new leads for drug discovery is described. The method can be used in solution-phase and solid-phase conditions. In the key step of the synthesis, the imido portion of the new molecule is formed in solution through intramolecular cyclization, under basic conditions, of a secondary amide nitrogen on a benzyl ester. A Wang resin carboxylic ester is used as the acylating agent under solid-phase conditions, allowing the cyclization to take place with simultaneous cleavage of the product from the resin ("cyclocleavage"). The synthetic method worked well with several couples of amino acids, independently from their configuration, and was used for the parallel synthesis of a series of fully characterized compounds. The use of iterative conditions in the solid phase (repeated addition of fresh solvent and potassium carbonate to the resin after filtering out the product-containing solution) allowed us to keep diastereoisomer content below the detection limit by HPLC and (1)H NMR (200 MHz). PMID:11549363

  3. Novel functionalized polymeric fabric and fiber material as solid support for solid-phase synthesis and biomedical applications

    NASA Astrophysics Data System (ADS)

    Xiang, Bei

    The aim of the research is to develop novel polymer solid support by modifying or fabricating polymeric fibrous materials for peptide synthesis and biomedical applications. Originally chemical inert isotactic polypropylene (iPP) fabric was utilized and modified to serve as a functional flexible planar solid support for solid phase peptide synthesis. The modification was achieved through thermal initiated radical grafting polymerization using acrylic acid, poly (ethylene glycol) diacrylate as monomers, and benzoyl peroxide as radical initiator. The iPP fabric was successfully functionalized and possessing as high as 0.7mmol/g carboxylic acid groups. Peptide ligand LHPQF was successfully synthesized on the new functional planar support. Specific enzyme immobilization was fulfilled on the functional iPP fabric support. A commercially available ethylene-acrylic acid copolymer was made into ultrafine copolymer fiber bundles which are composed of nanofibers with diameters ranging from 200nm to 800nm. Various mixing ratios of copolymer/matrix materials were utilized to explore the effect on the final nanofiber physical properties including morphology and stability in solvents. The surface carboxylic acid groups were further converted to amino groups before the functional nanofibers can be applied in solid phase peptide synthesis. Two peptide ligands, LHPQF and HWRGWV, were also successfully synthesized on the nanofiber bundles. Streptavidin and human immunoglobulin G specific binding with the corresponding ligand which was anchored on the nanofibers was conducted successfully to illustrate the potential applications of the nanofiber materials in biomedical field. Further study on the dispersion of the ethylene-acrylic acid nanofiber bundles was pursued to take advantage of the super high active surface area of functional nanofibers. To manipulate the polymer nanofibers during synthesis and bio-assays, a technique was developed to controllably assemble and disperse the

  4. Effects of gravity reduction on phase equilibria. Part 1: Unary and binary isostructural solids

    NASA Technical Reports Server (NTRS)

    Larson, D. J., Jr.

    1975-01-01

    Analysis of the Skylab II M553 Experiment samples resulted in the hypothesis that the reduced gravity environment was altering the melting and solidification reactions. A theoretical study was conducted to define the conditions under which such alteration of phase relations is feasible, determine whether it is restricted to space processing, and, if so, ascertain which alloy systems or phase reactions are most likely to demonstrate such effects. Phase equilibria of unary and binary systems with a single solid phase (unary and isomorphous) were considered.

  5. Thermally stable coexistence of liquid and solid phases in gallium nanoparticles.

    PubMed

    Losurdo, Maria; Suvorova, Alexandra; Rubanov, Sergey; Hingerl, Kurt; Brown, April S

    2016-09-01

    Gallium (Ga), a group III metal, is of fundamental interest due to its polymorphism and unusual phase transition behaviours. New solid phases have been observed when Ga is confined at the nanoscale. Herein, we demonstrate the stable coexistence, from 180 K to 800 K, of the unexpected solid γ-phase core and a liquid shell in substrate-supported Ga nanoparticles. We show that the support plays a fundamental role in determining Ga nanoparticle phases, with the driving forces for the nucleation of the γ-phase being the Laplace pressure in the nanoparticles and the epitaxial relationship of this phase to the substrate. We exploit the change in the amplitude of the evolving surface plasmon resonance of Ga nanoparticle ensembles during synthesis to reveal in real time the solid core formation in the liquid Ga nanoparticle. Finally, we provide a general framework for understanding how nanoscale confinement, interfacial and surface energies, and crystalline relationships to the substrate enable and stabilize the coexistence of unexpected phases. PMID:27454047

  6. Mechanism and microstructures in Ga2O3 pseudomartensitic solid phase transition.

    PubMed

    Zhu, Sheng-Cai; Guan, Shu-Hui; Liu, Zhi-Pan

    2016-07-21

    Solid-to-solid phase transition, although widely exploited in making new materials, challenges persistently our current theory for predicting its complex kinetics and rich microstructures in transition. The Ga2O3α-β phase transformation represents such a common but complex reaction with marked change in cation coordination and crystal density, which was known to yield either amorphous or crystalline products under different synthetic conditions. Here we, via recently developed stochastic surface walking (SSW) method, resolve for the first time the atomistic mechanism of Ga2O3α-β phase transformation, the pathway of which turns out to be the first reaction pathway ever determined for a new type of diffusionless solid phase transition, namely, pseudomartensitic phase transition. We demonstrate that the sensitivity of product crystallinity is caused by its multi-step, multi-type reaction pathway, which bypasses seven intermediate phases and involves all types of elementary solid phase transition steps, i.e. the shearing of O layers (martensitic type), the local diffusion of Ga atoms (reconstructive type) and the significant lattice dilation (dilation type). While the migration of Ga atoms across the close-packed O layers is the rate-determining step and yields "amorphous-like" high energy intermediates, the shearing of O layers contributes to the formation of coherent biphase junctions and the presence of a crystallographic orientation relation, (001)α//(201[combining macron])β + [120]α//[13[combining macron]2]β. Our experiment using high-resolution transmission electron microscopy further confirms the theoretical predictions on the atomic structure of biphase junction and the formation of (201[combining macron])β twin, and also discovers the late occurrence of lattice expansion in the nascent β phase that grows out from the parent α phase. By distinguishing pseudomartensitic transition from other types of mechanisms, we propose general rules to predict the

  7. Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

    PubMed

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

    2013-12-20

    Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees. PMID:24238710

  8. High-pressure chemistry of molecular solids: evidences for novel extended phases of carbon dioxide

    SciTech Connect

    Yoo, C S

    1999-07-22

    At high pressures and temperatures, many molecular solids become unstable and transform into denser extended phases. Recently, we have discovered evidences for two novel extended phases of carbon dioxide at high pressures and temperatures: (1) an ionic form of dimeric CO,, C02+C03*- at 8-13 GPa and above 2000 K [I] and (2) a polymeric phase CO,-V above 35 GPa and 1800 K [2,3]. These extended phases can be quenched at room temperature at low pressures, from which their molecular and crystal structures have been determined. These transitions occur to soften highly repulsive intermolecular potentials via delocalization of electrons at high pressures and temperatures. Based on these and other previous results, we conjecture that three fundamental mechanisms of high-pressure chemistry are ionization, polymerization, and metallization, occurring in high-density molecular solids and fluids. [carbon dioxide, polymeric COZ, ionic CO, dimer, high-pressure chemistry, electron delocalization

  9. A solid-state PWM phase-shifter. [Pulse Width Modulation

    SciTech Connect

    Ooi, Boon Teck; Dai, Shu Zu; Galiana, F.D. )

    1993-04-01

    The solid-state, pulse width modulated (PWM) phase-shifter is based on gate-turn-off (GTO) thyristors or other valves with force commutation capabilities. Besides serving the phase-shifter function, it offers regulated control over 3 independent quantities: the real power passing through it and the VARs on both sides to which it is connected. The power transferred can be bidirectional and the VARs can be leading or lagging.

  10. High-resolution low-noise 360-degree digital solid reconstruction using phase-stepping profilometry.

    PubMed

    Servin, Manuel; Garnica, Guillermo; Estrada, Julio C; Padilla, J M

    2014-05-01

    In this paper we describe a high-resolution, low-noise phase-shifting algorithm applied to 360 degree digitizing of solids with diffuse light scattering surface. A 360 degree profilometer needs to rotate the object a full revolution to digitize a three-dimensional (3D) solid. Although 360 degree profilometry is not new, we are proposing however a new experimental set-up which permits full phase-bandwidth phase-measuring algorithms. The first advantage of our solid profilometer is: it uses base-band, phase-stepping algorithms providing full data phase-bandwidth. This contrasts with band-pass, spatial-carrier Fourier profilometry which typically uses 1/3 of the fringe data-bandwidth. In addition phase-measuring is generally more accurate than single line-projection, non-coherent, intensity-based line detection algorithms. Second advantage: new fringe-projection set-up which avoids self-occluding fringe-shadows for convex solids. Previous 360 degree fringe-projection profilometers generate self-occluding shadows because of the elevation illumination angles. Third advantage: trivial line-by-line fringe-data assembling based on a single cylindrical coordinate system shared by all 360-degree perspectives. This contrasts with multi-view overlapping fringe-projection systems which use iterative closest point (ICP) algorithms to fusion the 3D-data cloud within a single coordinate system (e.g. Geomagic). Finally we used a 400 steps/rotation turntable, and a 640x480 pixels CCD camera. Higher 3D digitized surface resolutions and less-noisy phase measurements are trivial by increasing the angular-spatial resolution and phase-steps number without any substantial change on our 360 degree profilometer. PMID:24921790

  11. Direct molecular dynamics simulation of liquid-solid phase equilibria for a three-component plasma.

    PubMed

    Hughto, J; Horowitz, C J; Schneider, A S; Medin, Zach; Cumming, Andrew; Berry, D K

    2012-12-01

    The neutron-rich isotope ²²Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of ²²Ne in carbon-oxygen-neon systems on liquid-solid phase equilibria. Both liquid and solid phases are present simultaneously in our simulation volumes. We identify liquid, solid, and interface regions in our simulations using a bond angle metric. In general we find good agreement for the composition of liquid and solid phases between our MD simulations and the semianalytic model of Medin and Cumming. The trace presence of a third component, neon, does not appear to strongly impact the chemical separation found previously for two-component carbon and oxygen systems. This suggests that small amounts of ²²Ne may not qualitatively change how the material in white dwarf stars freezes. However, we do find systematically lower melting temperatures (higher Γ) in our MD simulations compared to the semianalytic model. This difference seems to grow with impurity parameter Q_{imp} and suggests a problem with simple corrections to the linear mixing rule for the free energy of multicomponent solid mixtures that is used in the semianalytic model. PMID:23368065

  12. Direct molecular dynamics simulation of liquid-solid phase equilibria for a three-component plasma

    NASA Astrophysics Data System (ADS)

    Hughto, J.; Horowitz, C. J.; Schneider, A. S.; Medin, Zach; Cumming, Andrew; Berry, D. K.

    2012-12-01

    The neutron-rich isotope 22Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of 22Ne in carbon-oxygen-neon systems on liquid-solid phase equilibria. Both liquid and solid phases are present simultaneously in our simulation volumes. We identify liquid, solid, and interface regions in our simulations using a bond angle metric. In general we find good agreement for the composition of liquid and solid phases between our MD simulations and the semianalytic model of Medin and Cumming. The trace presence of a third component, neon, does not appear to strongly impact the chemical separation found previously for two-component carbon and oxygen systems. This suggests that small amounts of 22Ne may not qualitatively change how the material in white dwarf stars freezes. However, we do find systematically lower melting temperatures (higher Γ) in our MD simulations compared to the semianalytic model. This difference seems to grow with impurity parameter Qimp and suggests a problem with simple corrections to the linear mixing rule for the free energy of multicomponent solid mixtures that is used in the semianalytic model.

  13. Influence of copolymer composition on the phase behavior of solid dispersions.

    PubMed

    Prudic, Anke; Kleetz, Tobias; Korf, Marcel; Ji, Yuanhui; Sadowski, Gabriele

    2014-11-01

    The incorporation of poorly soluble active pharmaceutical ingredients (APIs) into excipients (e.g., polymers) to formulate an amorphous solid dispersion is a promising strategy to improve the oral bioavailability of the API. The application of copolymer excipients allows access to combinations of different monomers and thus to the design of excipients to improve solid-dispersion properties. In this work, the thermodynamic phase behavior of solid dispersions was investigated as a function of the API, type of monomer, and copolymer composition. The glass-transition temperatures and API solubilities in the solid dispersions of naproxen and indomethacin in polyvinylpyrrolidone, polyvinyl acetate, and copolymers with different weight fractions of vinylpyrrolidone and vinyl actetate were investigated. It is shown that the thermodynamic phase behavior of API/copolymer solid dispersions is a function of monomer type and copolymer composition. This effect was also predicted by using the perturbed-chain statistical associating fluid theory (PC-SAFT). The glass-transition temperature of the solid dispersions was calculated with the Gordon-Taylor equation. PMID:25295846

  14. Magnetization studies of the nuclear spin ordered phases of solid 3He in silver sinters

    NASA Astrophysics Data System (ADS)

    Schuberth, E. A.; Kath, M.; Tassini, L.; Millan-Chacartegui, C.

    2005-08-01

    Solid 3He, in the bcc lattice between 34 and 100 bar, exhibits two nuclear magnetic ordered phases in the sub-mK temperature range, the so called U2D2 low (magnetic) field phase and the “high field phase” above 0.4 T. To determine the exact spin structure of these phases we started a project of neutron scattering from the ordered solid in collaboration with the Hahn-Meitner Institute, Berlin, and other European and US groups. For this experiment it is crucial to grow a single crystal within the sinter needed for cooling the solid to temperatures of the order of 500 μK (or even twenty times lower in the case of the hcp lattice which is formed above 100 bar) and to keep it there long enough to measure a magnetic neutron reflection. We studied the growth of crystals in Ag sinters of different pore size and with different growth speeds to find an optimal way to obtain single crystalline samples. As a first diagnostic step we performed pulsed NMR measurements in the ordered phases of solid 3He in a sinter of 2700 Å particle size down to temperatures of 450 μK at various molar volumes. We could keep the samples in the ordered state for as long as 140 h. The second method we used was SQUID magnetometry. For the low field phase TN was indicated by a drop of the intensity, both in the NMR signal and in the dc magnetization, whereas in the high field phase an increase of about 30% was observed below the ordering temperature. For the fabrication of the sinters a packing fraction of 50% and subsequent annealing proved to be very favorable to obtain cold ordered solid. Furthermore, we find that a paramagnetic surface contribution from a few monolayers of 3He exists down to 500 μK in addition to the bulk magnetization.

  15. Dynamically slow solid-to-solid phase transition induced by thermal treatment of DimimFeCl4 magnetic ionic liquid.

    PubMed

    de Pedro, Imanol; Fabelo, Oscar; García-Saiz, Abel; Vallcorba, Oriol; Junquera, Javier; Blanco, Jesús Angel; Waerenborgh, João Carlos; Andreica, D; Wildes, Andrew; Fernández-Díaz, María Teresa; Fernández, Jesús Rodríguez

    2016-08-01

    The results reported here represent the first direct experimental observations supporting the existence of a solid-to-solid phase transition induced by thermal treatment in magnetic ionic liquids (MILs). The phase transitions of the solid phases of 1,3-dimethylimidazolium tetrachloroferrate, DimimFeCl4, are closely related to its thermal history. Two series of solid-to-solid phase transitions can be described in this MIL: (i) from room temperature (RT) phase II [space group (s.g.) = P21] to phase I-a [s.g. = P212121] via thermal quenching or via fast cooling at T > 2 K min(-1); (ii) from phase I-a to phase I-b [s.g. = P21/c] when the temperature was kept above 180 K for several minutes. The latter involves a slow translational and reorientational dynamical process of both the imidazolium cation and the tetrachloroferrate anion and has been characterized using synchrotron and neutron powder diffraction and DFT (density functional theory) studies. The transition is also related to the modification of the super-exchange pathways of low-temperature phases which show a overall antiferromagnetic behavior. A combination of several experimental methods such as magnetometry, Mössbauer and muon spectroscopy together with polarized and non-polarized neutron powder diffraction has been used in order to characterize the different features observed in these phases. PMID:27439896

  16. Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas

    NASA Astrophysics Data System (ADS)

    Schneider, A. S.; Hughto, J.; Horowitz, C. J.; Berry, D. K.

    2012-06-01

    We determine the liquid-solid phase diagram for carbon-oxygen and oxygen-selenium plasma mixtures using two-phase molecular dynamics simulations. We identify liquid, solid, and interface regions using a bond angle metric. To study finite-size effects, we perform 27 648- and 55 296-ion simulations. To help monitor nonequilibrium effects, we calculate diffusion constants Di. For the carbon-oxygen system we find that DO for oxygen ions in the solid is much smaller than DC for carbon ions and that both diffusion constants are 80 or more times smaller than diffusion constants in the liquid phase. There is excellent agreement between our carbon-oxygen phase diagram and that predicted by Medin and Cumming. This suggests that errors from finite-size and nonequilibrium effects are small and that the carbon-oxygen phase diagram is now accurately known. The oxygen-selenium system is a simple two-component model for more complex rapid proton capture nucleosynthesis ash compositions for an accreting neutron star. Diffusion of oxygen, in a predominantly selenium crystal, is remarkably fast, comparable to diffusion in the liquid phase. We find a somewhat lower melting temperature for the oxygen-selenium system than that predicted by Medin and Cumming. This is probably because of electron screening effects.

  17. Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas.

    PubMed

    Schneider, A S; Hughto, J; Horowitz, C J; Berry, D K

    2012-06-01

    We determine the liquid-solid phase diagram for carbon-oxygen and oxygen-selenium plasma mixtures using two-phase molecular dynamics simulations. We identify liquid, solid, and interface regions using a bond angle metric. To study finite-size effects, we perform 27,648- and 55,296-ion simulations. To help monitor nonequilibrium effects, we calculate diffusion constants D(i). For the carbon-oxygen system we find that D(O) for oxygen ions in the solid is much smaller than D(C) for carbon ions and that both diffusion constants are 80 or more times smaller than diffusion constants in the liquid phase. There is excellent agreement between our carbon-oxygen phase diagram and that predicted by Medin and Cumming. This suggests that errors from finite-size and nonequilibrium effects are small and that the carbon-oxygen phase diagram is now accurately known. The oxygen-selenium system is a simple two-component model for more complex rapid proton capture nucleosynthesis ash compositions for an accreting neutron star. Diffusion of oxygen, in a predominantly selenium crystal, is remarkably fast, comparable to diffusion in the liquid phase. We find a somewhat lower melting temperature for the oxygen-selenium system than that predicted by Medin and Cumming. This is probably because of electron screening effects. PMID:23005226

  18. AUTOMATED SOLID PHASE EXTRACTION GC/MS FOR ANALYSIS OF SEMIVOLATILES IN WATER AND SEDIMENTS

    EPA Science Inventory

    Data is presented on the development of a new automated system combining solid phase extraction (SPE) with GC/MS spectrometry for the single-run analysis of water samples containing a broad range of organic compounds. The system uses commercially available automated in-line sampl...

  19. Thermal battery. [solid metal halide electrolytes with enhanced electrical conductance after a phase transition

    DOEpatents

    Carlsten, R.W.; Nissen, D.A.

    1973-03-06

    The patent describes an improved thermal battery whose novel design eliminates various disadvantages of previous such devices. Its major features include a halide cathode, a solid metal halide electrolyte which has a substantially greater electrical conductance after a phase transition at some temperature, and a means for heating its electrochemical cells to activation temperature.

  20. Solid-Phase Organic Synthesis and Combinatorial Chemistry: A Laboratory Preparation of Oligopeptides

    NASA Astrophysics Data System (ADS)

    Truran, George A.; Aiken, Karelle S.; Fleming, Thomas R.; Webb, Peter J.; Hodge Markgraf, J.

    2002-01-01

    The principles and practice of solid-phase organic synthesis and combinatorial chemistry are utilized in a laboratory preparation of oligopeptides. A parallel synthesis scheme is used to generate a series of tripeptides. A divergent synthesis scheme is used to prepare two pentapeptides, one of which is leucine enkephalin, a neurotransmitter known to be an analgesic agent.

  1. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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 AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING...

  2. COMPARISON OF TWO DIFFERENT SOLID PHASE EXTRACTION/LARGE VOLUME INJECTION PROCEDURES FOR METHOD 8270

    EPA Science Inventory

    Two solid phase (SPE) and one traditional continuous liquid-liquid extraction method are compared for analysis of Method 8270 SVOCs. Productivity parameters include data quality, sample volume, analysis time and solvent waste.

    One SPE system, unique in the U.S., uses aut...

  3. Final Report for Nucleation and growth of semiconductor nanocrystals by solid-phase reaction

    SciTech Connect

    P. D. Persans; T. M. Hayes

    2005-12-12

    This final report describes the technical output of a scientific program aimed at understanding the formation and structure of II-VI nanocrystals formed by solid phase precipitation within a glass environment. The principle probes were optical absorption spectroscopy to determine crystallite sizes, Raman scattering to determine composition, and x-ray absorption spectroscopy to study the evolution of local reactant environments.

  4. Headspace analysis of polar organic compounds in biological matrixes using solid phase microextraction (SPME)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analysis of biological fluids and waste material is difficult and tedious given the sample matrix. A rapid automated method for the determination of volatile fatty acids and phenolic and indole compounds was developed using a multipurpose sampler (MPS) with solid phase microextraction (SPME) and GC-...

  5. A Discovery-Oriented Approach to Solid-Phase Peptide Synthesis

    ERIC Educational Resources Information Center

    Bockman, Matthew R.; Miedema, Christopher J.; Brennan, Brian B.

    2012-01-01

    In this discovery-oriented laboratory experiment, students use solid-phase synthesis techniques to construct a dipeptide containing an unknown amino acid. Following synthesis and cleavage from the polymeric support, electrospray ionization-mass spectrometry is employed to identify the unknown amino acid that was used in the peptide coupling. This…

  6. Development of a Solid Phase Extraction Method for Agricultural Pesticides in Large-Volume Water Samples

    EPA Science Inventory

    An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC/MS) was developed for the trace determination of a variety of agricultural pesticides and selected transformation products in large-volume high-elevation lake water sa...

  7. Determination of Plant Volatiles Using Solid Phase Microextraction GC-MS

    ERIC Educational Resources Information Center

    Van Bramer, Scott; Goodrich, Katherine R.

    2015-01-01

    This experiment combines analytical techniques of solid phase microextraction and gas chromatography-mass spectrometry with easily relatable and accessible plant volatile chemistry (floral and vegetative scents of local/available plants). The biosynthesis and structure of these chemicals are of interest in the areas of organic chemistry,…

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

    ERIC Educational Resources Information Center

    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…

  9. Use of Solid Phase Extraction in the Biochemistry Laboratory to Separate Different Lipids

    ERIC Educational Resources Information Center

    Flurkey, William H.

    2005-01-01

    Solid-phase extraction (SPE) was used to demonstrate how various lipids and lipid classes could be separated in a biochemistry laboratory setting. Three different SPE methods were chosen on their ability to separate a lipid mixture, consisting of a combination of a either a fatty acid, a triacylglycerol, a mono- or diacylglycerol, phospholipid,…

  10. Dopant activation during solid phase crystallization of poly-Si and influence of fluorine and hydrogen

    SciTech Connect

    Kalkan, A.K.; Kingi, R.M.; Fonash, S.J.

    1997-07-01

    Dopant activation for ion implanted solid phase crystallized (SPC) a-Si:H films, deposited by low temperature PECVD, was investigated. The impact of film thickness, the effect of subsequent hydrogenation, and a possible role for fluorine in this process have been studied.