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1

CONTROL OF A PULSED LIQUID-LIQUID EXTRACTION COLUMN BASED ON A MULTILEVEL SYSTEM OF AUTOMATA  

Microsoft Academic Search

This paper presents the real-time application of the learning control theory to the control of a chemical pilot plant: a pulsed liquid-liquid extraction column.The behaviour of an agitated liquid-liquid extraction column can be related to random mechanisms such as the phenomena of droplets breakage and coalescence. Previous studies on hydrodynamic and mass transfer aspects showed that a pulsed liquid-liquid extraction

K. NAJIM; M. V. LE LANN

1988-01-01

2

Development and Verification of a Mathematical Model for a Pulsed Extraction Column.  

National Technical Information Service (NTIS)

Experimentally determined concentration profiles were obtained from operating pulse extraction columns for a uranium-nitric acid system. Theoretical profiles were generated from a computer model based on the operating conditions, in which certain physical...

R. H. Haas

1984-01-01

3

Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems  

SciTech Connect

A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to ``seek`` any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these bubbles have a net velocity towards the end of the column where the nominal interface is located, the solids are swept in that direction too. These solids tend to gather in a three-phase ``crud`` layer at the nominal interface point. At equilibrium, about the same amount breaks off from the crud layer and escapes into the liquid exiting from that end of the column as enters it from the other side. If large enough, the crud layer can even interfere with interface detection and control equipment. In packed-column extraction systems, an additional problem is that feed solids can accumulate within the packing material to the point that the column `` floods`` or even totally plugs. The keys to preventing solids-related problems is the correct choice of interface level, and with packed columns, the addition of a ``pulsing leg`` at the bottom of the column. Pulsing packed column systems not only prevents solids from settling onto packing material but it also increses the number of theoretical stages available for extraction. 3 figs., 2 tabs.

Siemer, D.D.

1989-04-18

4

Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems  

Microsoft Academic Search

A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to ``seek`` any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these

Siemer

2010-01-01

5

Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems  

Microsoft Academic Search

A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to seek'' any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these

Siemer

1989-01-01

6

Technique de l'extraction en colonnes pulsees. (Technology of extraction by solvent in pulsed columns).  

National Technical Information Service (NTIS)

Since its creation, the CEA (Commissariat a l'energie atomique) has produced several separation processes for natural or enriched uranium treatment and the treatment of spent fuels coming from nuclear reactors. Among these technologies, extraction by solv...

P. Ros

1992-01-01

7

Extraction of Caprolactam with Toluene in a Pulsed Disc and Doughnut Column—Part I: Recommendation of a Model for Hydraulic Characteristics  

Microsoft Academic Search

Caprolactam, the monomer for Nylon?6, is industrially recovered from an aqueous feed containing ammonium sulphate by extraction with organic solvents like benzene, toluene, or chlorinated hydrocarbons followed by back?extraction with water. Extraction columns like the Rotating Disk Contactor and Pulsed Packed Column are industrially applied. In this paper a model is recommended for the description of the hydraulic characteristics of

M. L. van Delden; N. J. M. Kuipers; A. B. de Haan

2006-01-01

8

Applicability of Hydroxylamine Nitrate Reductant in Pulse-Column Contactors.  

National Technical Information Service (NTIS)

Uranium and plutonium separations were made from simulated breeder reactor spent fuel dissolver solution with laboratory-sized pulse column contactors. Hydroxylamine nitrate (HAN) was used for reduction of plutonium (1V). An integrated extraction-partitio...

D. J. Reif

1983-01-01

9

Applicability of hydroxylamine nitrate reductant in pulse-column contactors  

SciTech Connect

Uranium and plutonium separations were made from simulated breeder reactor spent fuel dissolver solution with laboratory-sized pulse column contactors. Hydroxylamine nitrate (HAN) was used for reduction of plutonium (1V). An integrated extraction-partition system, simulating a breeder fuel reprocessing flowsheet, carried out a partial partition of uranium and plutonium in the second contactor. Tests have shown that acceptable coprocessing can be ontained using HAN as a plutonium reductant. Pulse column performance was stable even though gaseous HAN oxidation products were present in the column. Gas evolution rates up to 0.27 cfm/ft/sup 2/ of column cross section were tested and found acceptable.

Reif, D.J.

1983-05-01

10

THE DESIGN AND OPERATION OF INDUSTRIAL SCALE PULSE COLUMNS FOR PUREX SERVICE  

Microsoft Academic Search

The development of current recommendations for Purex pulse column ; designs is discussed and reviewed. To obtain a better understanding of the ; radioactive solvent extraction process, a brief description of the Purex Process ; is offered in the form of a flowsheet. The advantages of the pulse column over ; the packed column and the mixersettler are also discussed.

G. L. Richardson; A. M. Platt

1961-01-01

11

Calculation of a TBP Extraction Column.  

National Technical Information Service (NTIS)

Problems involving the number of stages in an extraction column and the equipment needed in most aqueous methods of reprocessing of nuclear fuels were studied. A solution for the separation of uranium from fission products in a feed solution that contains...

M. L. de Lima Soares

1973-01-01

12

Rapid Column Extraction Methods for Urine  

SciTech Connect

A new fecal analysis method that dissolves plutonium oxide was developed at the Westinghouse Savannah River Site. Diphonix Resin (Eichrom Industries), is used to pre-concentrate the actinides from digested fecal samples. A rapid microwave digestion technique is used to remove the actinides from the Diphonix Resin, which effectively extracts plutonium and americium from acidic solutions containing hydrofluoric acid. After resin digestion, the plutonium and americium are recovered in a small volume of nitric acid that is loaded onto small extraction chromatography columns, TEVA Resin and TRU Resin (Eichrom Industries). The method enables complete dissolution of plutonium oxide and provides high recovery of plutonium and americium with good removal of thorium isotopes such as thorium-228.

Maxwell, S.L. III

2000-06-09

13

Instrument for the measurement and determination of chemical pulse column parameters  

DOEpatents

An instrument for monitoring and measuring pneumatic driving force pulse parameters applied to chemical separation pulse columns obtains real time pulse frequency and root mean square amplitude values, calculates column inch values and compares these values against preset limits to alert column operators to the variations of pulse column operational parameters beyond desired limits.

Marchant, Norman J. (Idaho Falls, ID); Morgan, John P. (Idaho Falls, ID)

1990-01-01

14

Optimization of the process for recovering caprolactam from wastewater in a pulsed-sieve-plate column using green design methodologies  

Microsoft Academic Search

In the process for recovering caprolactam from wastewater using a pulsed-sieve-plate column, benzene, which is used as the extracting solvent, may seriously impact the environment due to its emission during the normal operation of the process. Green design methodology is adopted to redesign the pulsed- sieve-plate column in the recovery process. The quantity of benzene is also optimized by green

Chao-Hong He; Yun-He Gao; Shuang-Hua Yang; David W. Edwards

2004-01-01

15

Using solvent extraction to process nitrate anion exchange column effluents  

SciTech Connect

Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO), a new organophosphorous extractant, and a new centrifugal mixer-settler both recently developed at Argonne were evaluated for their potential use in the recovery of actinides from nitrate anion exchange column effluents. The performance of the extractant was evaluated by measuring the extraction coefficient values as a function of acid and salt concentration. Additional performance parameters include extraction coefficient behavior as a function of the total metal concentration in the organic phase, and comparison of different stripping and organic scrubbing techniques. A simulated effluent stream was used to evaluate the performance of the centrifugal mixer-settlers by comparing experimental and calculated interstage concentration profiles. Both the CMPO extractant and the centrifugal mixer-settlers have potential for processing nitrate column effluents, particularly if the stripping behavior can be improved. Details of the proposed process are presented in the flowsheet and contactor design analyses.

Yarbro, S.L.

1987-10-01

16

SOIL VAPOR EXTRACTION COLUMN EXPERIMENTS ON GASOLINE CONTAMINATED SOIL  

EPA Science Inventory

Soil vapor extraction (SVE) is a technique that is used to remove volatile organic compounds from unsaturated soils. Air is pumped through and from the contaminated zone to remove vapor phase constituents. In the work, laboratory soil column experiments were conducted using a gas...

17

Pulsed Airborne Lidar Measurements of C02 Column Absorption  

NASA Technical Reports Server (NTRS)

We report on airborne lidar measurements of atmospheric CO2 column density for an approach being developed as a candidate for NASA's ASCENDS mission. It uses a pulsed dual-wavelength lidar measurement based on the integrated path differential absorption (IPDA) technique. We demonstrated the approach using the CO2 measurement from aircraft in July and August 2009 over four locations. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The 2009 measurements have been analyzed in detail and the results show approx.1 ppm random errors for 8-10 km altitudes and approx.30 sec averaging times. Airborne measurements were also made in 2010 with stronger signals and initial analysis shows approx. 0.3 ppm random errors for 80 sec averaging times for measurements at altitudes> 6 km.

Abshire, James B.; Riris, Haris; Allan, Graham R.; Weaver, Clark J.; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William E.; Rodriquez, Michael; Browell, Edward V.

2011-01-01

18

Modeling, simulation and control of liquid-liquid extraction columns  

Microsoft Academic Search

A model describing the hydrodynamics and mass transfer of countercurrent liquid-liquid extraction columns is developed and solved. The hydrodynamic model assumes that the dispersed-phase drops behave as spheres of uniform diameter. The model has been found to be qualitatively in agreement with experimental results published in the literature. It is shown that conventional dispersion interface level control using the continuous-phase

O. Weinstein; R. Semiat; D. R. Lewin

1998-01-01

19

Reactive extraction of lactic acid in a packed column  

Microsoft Academic Search

Reactive extraction of lactic acid was performed continuously in a packed column. The 0.6 M trioctylamine (TOA)\\/l-chlorobutane\\u000a system was used as an extradant. The initial concentration of lactic acid was 10 wt% based on fermentation results. Raschig\\u000a rings (5 and 7 mm diameter) were used to measure hydrodynamic data. Disperse phase holdup was nearly constant at Vdd,f.It can be seen

Dong Hoon Han; Won Hi Hong

1998-01-01

20

Simultaneous extraction of six pesticides using a dual-column extraction procedure  

SciTech Connect

A method was developed that allowed for the simultaneous extraction of six pesticides (three chloro-s-triazines, a substituted amide, an organic phosphate, and a benzoic acid derivative) from either sod or water samples. This rnethod utilizes two types of solid-phase extraction columns, one reverse phase, and one anion exchange column, connected in series to extract all six compounds from a single sample. After separate elution of the two columns, high pressure liquid chromatography was employed to analyze the benzoic acid derivative utilizing a C-18 column and paired Ion techniques with a detection limit of 6 {mu}g L{sup -1}. A gas chromatography equipped with a N-P detector, was used to analyze the remaining five compounds. The detectable limit for the chloro-s-triazines was 3 {mu}g L{sup -1} while the detection limit of the substituted amide was 6 {mu}g L{sup -1}. 11 refs., 1 fig., 1 tab.

Watts, D.W.; Bogus, E.R.; Hall, J.K.; Mumma, R.O. [Coastal Plains Research Center, Florence, SC (United States)

1994-03-01

21

Obtaining high-purity tantalum pentoxide in a pulsed column operating in the countercurrent mode  

Microsoft Academic Search

The advantages of the purification of tantalum hydroxide in the continuous mode on a pulsed column have been studied. This\\u000a method allows for the obtainment of a high and stable quality of tantalum hydroxide, a decrease in the losses of the final\\u000a product yield, and a considerable increase in labor productivity.

N. V. Zots; A. A. Kopyrin; A. V. Nechaev; S. V. Shestakov

2010-01-01

22

Hydrodynamics of a packed countercurrent column for the gas extraction  

Microsoft Academic Search

The hydraulic capacity of a countercurrent column with gauze packing was examined at pressures between 8 and 30 MPa and temperatures between 313 and 373 K. The systems used were water + carbon dioxide, aqueous surfactant solution + carbon dioxide, and Toco, a substance whose physical properties are roughly similar to those of α-Tocopherol + carbon dioxide. A distinctive change

Ron Stockfleth; Gerd Brunner

1999-01-01

23

Extreme degree of ionization in micro-capillary plasma columns heated by ultrafast current pulses  

NASA Astrophysics Data System (ADS)

The efficient generation of dense large-scale plasma columns with very high degree of ionization and high homogeneity can enable fundamental plasma studies and a variety of promising applications. We demonstrate the generation of dense large-aspect-ratio plasmas columns with extremely high degree of ionization in micro-capillary channels heated by ultrafast discharge current pulses. Xenon plasma columns were ionized to the Co-like stage (Xe XXVIII) injecting 37 kA current pulses with 4 ns risetime into of 500 micrometer diameter, with lines from the Fe-like ion (Xe XXIX) also visible in the spectra. Sequences of time-resolved filtered pinhole images of the plasma column show a symmetric compression leading to 300: 1 aspect-ration plasma channels. The experimental results, that include ionization of Al impurities up to the H-like stage, support model simulations in showing that rapid ohmic heating of micro-capillary channels with relatively modest currents can generate very hot dense plasma columns which electron temperature could approach 1 KeV.

Rocca, Jorge; Li, Jing; Avaria, Gonzalo; Grisham, Michael; Tomasel, Fernando; Shlyaptsev, Vyacheslav

2012-10-01

24

Column chromatographic extraction and preparation of cordycepin from Cordyceps militaris waster medium  

Microsoft Academic Search

Large amounts of solid medium containing cordycepin, used in the industrial production of Cordyceps militaris through solid fermentation, are discarded as waste and contaminate the environment. We have developed a new column chromatographic extraction (CCE) method for the extraction of cordycepin from this waste and a preparation method for further separation and purification. Dried waste material was imbibed in four

He Ni; Xiao-Hong Zhou; Hai-Hang Li; Wen-Fang Huang

2009-01-01

25

Supercritical carbon dioxide extraction of rice bran oil and column partition fractionation of ?-oryzanols  

Microsoft Academic Search

This work studies how pressure and temperature affect supercritical carbon dioxide extraction of rice bran oil from powdered rice bran, followed by the concentration and isolation of ?-oryzanols by column partition purification. The two purest ?-oryzanols (>98wt.%) were isolated from reagent chemical ?-oryzanols by preparative reverse-phase high-pressure liquid chromatography. In searching for a suitable range of extraction conditions, supercritical extraction

Chao-Rui Chen; Ling-Ya Wang; Chih-Hung Wang; Wai-Jane Ho; Chieh-Ming J. Chang

2008-01-01

26

Applicability of various brands of mixed-phase extraction columns for opiate extraction from blood and serum.  

PubMed

Four commercially available types of mixed-phase solid-phase extraction (SPE) columns (Bond Elut Certify, Isolute Confirm HCX, Chromabond Drug and Bakerbond Narc-2) were examined in order to compare the extraction efficiencies and chromatographic purity of extracts. The absolute recovery of morphine, 6-monoacetylmorphine and codeine was examined in blood and serum (ten samples each at two concentration levels), using SPE columns of the same batch. GC-MS (ion trap) and HPLC with amperometric detection were used for quantitation. A distinct variability in extraction recovery was observed among the same batches of all brands of SPE columns. All extracts were chromatographically pure and no interfering peaks were observed, neither in GC-MS nor in HPLC examinations, but in some extracts large peaks of plasticizers were identified. The measurements of flow velocities of the same samples of blood or serum through the SPE columns of the same batch showed very large variability of random character. The morphometric analysis of particles was performed for two batches of each sort of SPE columns by means of an image analysing system. Symmetrical distribution of particle size was observed only in Chromabond MN Drug packing, while in other cartridges large fractions of fine particles and nonhomogenous distribution were found. Only in one case the morphometric findings were pretty concordant with the data available from the manufacturer; in two cases, observed data varied considerably from that expected, and in one case no information was available at all. The study showed generally that there was room for improvement in the quality of mixed-phase SPE columns. PMID:8891914

Bogusz, M J; Maier, R D; Schiwy-Bochat, K H; Kohls, U

1996-08-30

27

Cost/performance comparison between pulse columns and centrifugal contactors designed to process Clinch River Breeder Reactor fuel  

SciTech Connect

A comparison between pulse columns and centrifugal contactors was made to determine which type of equipment was more advantageous for use in the primary decontamination cycle of a remotely operated fuel reprocessing plant. Clinch River Breeder Reactor (CRBR) fuel was chosen as the fuel to be processed in the proposed 1 metric tonne/day reprocessing facility. The pulse columns and centrifugal contactors were compared on a performance and total cost basis. From this comparison, either the pulse columns or the centrifugal contactors will be recommended for use in a fuel reprocessing plant built to reprocess CRBR fuel. The reliability, solvent exposure to radiation, required time to reach steady state, and the total costs were the primary areas of concern for the comparison. The pulse column units were determined to be more reliable than the centrifugal contactors. When a centrifugal contactor motor fails, it can be remotely changed in less than one eight hour shift. Pulse columns expose the solvent to approximately five times as much radiation dose as the centrifugal contactor units; however, the proposed solvent recovery system adequately cleans the solvent for either case. The time required for pulse columns to reach steady state is many times longer than the time required for centrifugal contactors to reach steady state. The cost comparison between the two types of contacting equipment resulted in centrifugal contactors costing 85% of the total cost of pulse columns when the contactors were stacked on three levels in the module. If the centrifugal contactors were all positioned on the top level of a module with the unoccupied volume in the module occupied by other equipment, the centrifugal contactors cost is 66% of the total cost of pulse columns. Based on these results, centrifugal contactors are recommended for use in a remotely operated reprocessing plant built to reprocess CRBR fuel.

Ciucci, J.A. Jr.

1983-12-01

28

The setup of an extraction system coupled to a hydrogen isotopes distillation column  

SciTech Connect

Among the most difficult problems of cryogenic distillation one stands apart: the extraction of the heavy fraction. By an optimal design of the cycle scheme, this problem could be avoided. A 'worst case scenario' is usually occurring when the extracted fraction consists of one prevalent isotope such as hydrogen and small amounts of the other two hydrogen isotopes (deuterium and/or tritium). This situation is further complicated by two parameters of the distillation column: the extraction flow rate and the hold-up. The present work proposes the conceptual design of an extraction system associated to the cryogenic distillation column used in hydrogen separation processes. During this process, the heavy fraction (DT, T{sub 2}) is separated, its concentration being the highest at the bottom of the distillation column. From this place the extraction of the gaseous phase can now begin. Being filled with adsorbent, the extraction system is used to temporarily store the heavy fraction. Also the extraction system provides samples for the gas Chromatograph. The research work is focused on the existent pilot plant for tritium and deuterium separation from our institute to validate the experiments carried out until now. (authors)

Zamfirache, M.; Bornea, A.; Stefanescu, I.; Bidica, N.; Balteanu, O.; Bucur, C. [INC-DTCI, ICSIRm. Valcea, Uzinei Street 4, Rm. Valcea (Romania)

2008-07-15

29

Determination of zearalenone in grains by high-performance liquid chromatography–tandem mass spectrometry after solid-phase extraction with RP18 columns or immunoaffinity columns  

Microsoft Academic Search

In this paper a robust, sensitive and selective LC–MS–MS method for the determination of zearalenone (ZON) in several cereals is described. Sample preparation was performed by extraction of the commodities with a mixture of acetonitrile and water followed by solid-phase extraction with RP-18 columns or immunoaffinity columns. The selective determination of ZON was achieved with an atmospheric pressure chemical ionization

Peter Zöllner; Justus Jodlbauer; W Lindner

1999-01-01

30

Airborne Measurements of Atmospheric Methane Column Abundance Made Using a Pulsed IPDA Lidar  

NASA Technical Reports Server (NTRS)

We report airborne measurements of the column abundance of atmospheric methane made over an altitude range of 3-11 km using a direct detection IPDA lidar with a pulsed laser emitting at 1651 nm. The laser transmitter was a tunable, seeded optical parametric amplifier (OPA) pumped by a Nd:YAG laser and the receiver used a photomultiplier detector and photon counting electronics. The results follow the expected changes with aircraft altitude and the measured line shapes and optical depths show good agreement with theoretical calculations.

Riris, Haris; Numata, Kenji; Li, Steve; Wu, Stewart; Ramanathan, Anamd; Dawsey, Martha; Mao, Jianping; Kawa, Randolph; Abshire, James B.

2012-01-01

31

Airborne measurements of atmospheric methane column abundance using a pulsed integrated-path differential absorption lidar.  

PubMed

We report airborne measurements of the column abundance of atmospheric methane made over an altitude range of 3-11 km using a direct detection integrated-path differential-absorption lidar with a pulsed laser emitting at 1651 nm. The laser transmitter was a tunable, seeded optical parametric amplifier pumped by a Nd:YAG laser, and the receiver used a photomultiplier detector and photon-counting electronics. The results follow the expected changes with aircraft altitude, and the measured line shapes and optical depths show good agreement with theoretical calculations. PMID:23207402

Riris, Haris; Numata, Kenji; Li, Steve; Wu, Stewart; Ramanathan, Anand; Dawsey, Martha; Mao, Jianping; Kawa, Randolph; Abshire, James B

2012-12-01

32

Use of Cyanopropyl-Bonded HPLC Column for Bioassay-Directed Fractionation of Organic Extracts from Incinerator Emissions.  

National Technical Information Service (NTIS)

The present study has shown that cyanopropyl-(CN) bonded silica HPLC columns are applicable for the fractionation of mass and mutagenic activity of organic extracts from some incinerator emissions. Dichloromethane-extractable organics from particles emitt...

D. M. DeMarini R. W. Williams L. R. Brooks M. S. Taylor

1992-01-01

33

Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography  

USGS Publications Warehouse

A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

Belisle, A.A.; Swineford, D.M.

1988-01-01

34

Nafion membrane electrophoresis with direct and simplified end-column pulse electrochemical detection of amino acids.  

PubMed

A novel electrophoresis technique, in which the separation column was replaced by a strip of Nafion membrane (5.0 cm x 0.20 mm x 0.25 mm), was developed for the separation of an amino acid mixture (glycine, asparic acid and lysine), followed by quadruple-pulse electrochemical detection. Nafion membrane contains hydrophilic pores (10-20 A and 50-60 A in size) acting as very narrow electrophoresis channels. The fixed-charge sites (-SO(3) (-)) on the hydrophilic pore surface provide a strong charged background. A platinum disk electrode (0.90 mm inner diameter) was employed as the detection electrode and the electrophoresis cathode was used as the quasi-reference and counter electrode for the end-column electrochemical detector, without decoupler. Under optimized conditions the mixture of amino acids could be separated at a voltage of only 90 V with a detection limit of 10(-7) M, indicating that Nafion membrane electrophoresis is a potentially attractive technique for the separation of small organic molecules or ions. PMID:14743490

Fang, Cheng; Wu, Bingliang; Zhou, Xingyao

2004-01-01

35

Dynamics of a Finite Liquid Oxygen (LOX) Column in a Pulsed Magnetic Field  

NASA Technical Reports Server (NTRS)

It is well known that liquid oxygen has a sufficient paramagnetic susceptibility that a strong magnetic field gradient can lift it in the earth's gravitational field. The movement of liquid oxygen is vital to the space program since it one of the primary oxidizers used for propulsion. Transport of liquid oxygen (LOX) via direct interaction of the magnetic fields (B field) with the fluid is a current topic of research and development at Kennedy Space Center, FL. This method of transporting (i.e. pumping) LOX may have particular advantages on Mars and other reduced gravitational environments, namely safety and reliability. This paper will address transport of a magnetic fluid, LOX, via phased-pulsed electromagnets acting on the edge of the column of fluid. The authors have developed a physical model from first-principles for the motion of a magnetic fluid in a particular U-tube geometry subjected to a pulsed magnetic field from an arbitrary solenoidal electromagnet. Experimental data that have been collected from the analogous geometry correlate well to that of the ab-initio calculations.

Youngquist, Robert; Immer, Christopher; Lane, John; Simpson, James; Steinrock, T. (Technical Monitor)

2002-01-01

36

Extraction of otoacoustic distortion product sources using pulse basis functions.  

PubMed

Distortion product otoacoustic emissions (DPOAEs) acquired in normal-hearing subjects show considerable variation in amplitude with varying frequency. This is known as DPOAE fine structure. It is widely accepted that fine structure results from wave interference from two DPOAE sources, a non-linear generation component and a coherent reflection component. Here a method is presented that decomposes short-pulse DPOAE recordings into pulse basis functions and enables the quantification of both source components in the time domain, independent of their relative phase and at low cost of measurement time. Input-output functions utilizing the extracted primary-source component are analyzed. PMID:23862908

Zelle, Dennis; Gummer, Anthony W; Dalhoff, Ernst

2013-07-01

37

Pulse Profiles, Accretion Column and a flare in Gx 1+4 During a Faint State  

NASA Technical Reports Server (NTRS)

The Rossi X-ray Timing Explorer (RXTE) spacecraft observed the X-ray pulsar GX 1+4 for a period of 34 hours on July 19/20 1996. The source faded from an intensity of approx. 20 mcrab to a minimum of less than or equal to 0.7 mcrab and then partially recovered towards the end of the observation. This extended minimum lasted approx. 40,000 seconds. Phase folded light curves at a barycentric rotation period of 124.36568 +/- 0.00020 seconds show that near the center of the extended minimum the source stopped pulsing in the traditional sense but retained a weak dip feature at the rotation period. Away from the extended minimum the dips are progressively narrower at higher energies and may be interpreted as obscurations or eclipses of the hot spot by the accretion column. The pulse profile changed from leading-edge bright before the extended minimum to trailing-edge bright after it. Data from the Burst and Transz'ent Source Experiment (BATSE) show that a torque reversal occurred less than 10 days after our observation. Our data indicate that the observed rotation departs from a constant period with a P/P value off approx. -5% per year at a 4.5(sigma) significance. We infer that we may have serendipitously obtained data. with high sensitivity and temporal resolution about the time of an accretion disk spin reversal. We also observed a rapid flare which had some precursor activity close to the center of the extended minimum.

Giles, A. B.; Galloway, D. K.; Greenhill, J. G.; Storey, M. C.; Wilson, C. A.

1999-01-01

38

Application of the porapak q column extraction method for tomato flavor volatile analysis.  

PubMed

The Porapak Q column method (PQM) was compared to the method of simultaneous distillation extraction (SDE) under reduced pressure for extraction of the volatile compounds produced by tomato cv. Momotaro. The PQM was found to be effective at trapping and isolating many low and high boiling point volatile compounds and at producing the very desirable natural ripe tomato flavor of extracts. The SDE method was less effective in isolating the higher boiling point volatile compounds and caused deterioration of volatile compounds due to the heating process that takes place during extraction, resulting in an unpleasant boiled green tomato flavor of extracts. The advantages of using the PQM are its simplicity and its high efficiency in isolating many volatile compounds from nonvolatile materials at room temperature. A total of 367 volatile compounds were isolated by the PQM. Of these, hexanal, (Z)-3-hexenal, (E)-2-hexenal, 2- and 3-methylbutanol, and 2-phenylethanol were relatively more abundant than other compounds and (Z)-3-hexenal showed the highest relative amount. PMID:12033802

Maneerat, Chamorn; Hayata, Yasuyoshi; Kozuka, Hiroshi; Sakamoto, Koji; Osajima, Yutaka

2002-06-01

39

Determination of magnolol and honokiol in Magnoliae Cortex using supercritical fluid chromatography on-line coupled with supercritical fluid extraction by on-column trapping  

Microsoft Academic Search

An assay of magnolol and honokiol in Magnoliae Cortex was established by on-line supercritical fluid chromatography (SFC) coupled with supercritical fluid extraction (SFE).With an amino column as the trapping and separation column, magnolol and honokiol were extracted and focused at the column head as a narrow band, even if 5% methanol was added to the supercritical carbon dioxide as an

Keiichi Suto; Yuji Ito; Kazuhiko Sagara; Hideji Itokawa

1997-01-01

40

A coaxial tube model of the cerebrospinal fluid pulse propagation in the spinal column.  

PubMed

The dynamics of the movement of the cerebrospinal fluid (CSF) may play an important role in the genesis of pathological neurological conditions such as syringomyelia, which is characterized by the presence of a cyst (syrinx) in the spinal cord. In order to provide sound theoretical grounds for the hypotheses that attribute the formation and growth of the syrinx to impediments to the normal movement of the CSF, it is necessary to understand various modes through which CSF pulse in the spinal column propagates. Analytical models of small-amplitude wave propagation in fluid-filled coaxial tubes, where the outer tube represents dura, the inner tube represents the spinal cord, and the fluid is the CSF, have been used to that end. However, so far, the tendency was to model one of the two tubes as rigid and to neglect the effect of finite thickness of the tube walls. The aim of this study is to extend the analysis in order to address these two potentially important issues. To that end, classical linear small-amplitude analysis of wave propagation was applied to a system consisting of coaxial tubes of finite thickness filled with inviscid incompressible fluid. General solutions to the governing equations for the case of harmonic waves in the long wave limit were replaced with the boundary conditions to yield the characteristic (dispersion) equation for the system. The four roots of the characteristic equation correspond to four modes of wave propagation, of which the first three are associated with significant motion of the CSF. For the normal range of parameters the speeds of the four modes are c(1)=13 ms, c(2)=14.7 ms, c(3)=30.3 ms, and c(4)=124.5 ms, which are well within the range of values previously reported in experimental and theoretical studies. The modes with the highest and the lowest speeds of propagation can be attributed to the dura and the spinal cord, respectively, whereas the remaining two modes involve some degree of coupling between the two. When the thickness of the spinal cord, is reduced below its normal value, the first mode becomes dominant in terms of the movement of the CSF, and its speed drops significantly. This suggests that the syrinx may be characterized by an abnormally low speed of the CSF pulse. PMID:19102567

Cirovic, Srdjan

2009-02-01

41

A 960-fps sub-sampling object extraction CMOS image sensor with 12-bit column parallel ADCs and ALUs  

Microsoft Academic Search

A CMOS image sensor with highly accurate object extraction pre-processing functions by 960-fps sub-sampling operation, 12-bit column parallel successive approximation ADCs and column parallel ALUs has been developed. The pixel is composed of four transistors type pixel which shares the source follower transistor and the pixel select transistor. The each ADC is composed of the noise and signal holding capacitance,

Yuichi Motohashi; Takashi Kubo; Hiroaki Kanto; Tomoyasu Tate; Shigetoshi Sugawa

2007-01-01

42

[Reparation and application of perfluorodecyl modified silica monolithic capillary column in extraction and enrichment of perfluorooctane sulfonates].  

PubMed

A perfluorodecyl modified silica monolithic capillary column has been prepared by using sol-gel method. The preparation steps included hydrolysis of alkoxy silane, fasculation of silanol, gelation, aging, meso-pore preparation, drying and surface modification. It could be used as a solid phase extraction (SPE) microcolumn for extraction and enrichment of perfluorooctane sulfonate (PFOS). The enrichment characteristics and efficiency of the perfluorodecyl modified monolithic silica capillary column has been investigated and compared with C18 silica monolithic capillary column. The results indicated that the perfluorodecyl modified silica monolithic capillary column ( 15 cm x 75 microm) had a higher adsorption capacity and a better enrichment selectivity for PFOS. The average adsorption capacity of the perfluorodecyl modified silica monolithic capillary column was 75 ng. And when the PFOS mass concentration in sample was 0. 25 mg/L, the enrichment factor was 29-fold in average. Owing to the good performance of the perfluorodecyl modified silica monolithic capillary column, it can be used for the extraction and enrichment of trace PFOS in water to meet the requirements of water quality monitoring and analysis. PMID:22268350

Huang, Ke; Zhou, Naiyuan; Chen, Bo

2011-10-01

43

Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption in the ASCENDS 2011 Airborne Campaign  

NASA Astrophysics Data System (ADS)

We have previously demonstrated an efficient pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. Our team participated in the 2010 ASCENDS airborne campaigns we flew airborne version of the CO2 and O2 lidar on the NASA DC-8. The CO2 lidar measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line using 250 mW average laser power, 30 wavelength samples per scan and 300 scans per second. Most flights had 5-6 altitude steps to > 12 km, and clear CO2 line shapes were observed at all altitudes. Our post-flight analysis estimated the lidar range and pulse energies at each wavelength every second. We then solved for the best-fit CO2 absorption line shape, and calculated the Differential Optical Depth (DOD) at the line peak. We compared these to CO2 DODs calculated from spectroscopy based on HITRAN 2008 and the conditions from airborne in-situ readings. Analysis of the 2010 measurements over the Pacific Ocean and Lamont OK shows the expected ~linear change of the peak DOD with altitude. For measurements at altitudes > 6 km the random errors were ~ 0.3 ppm for 80 sec averaging times. After the 2010 flights we improved the airborne lidar's scan uniformity, calibration and receiver sensitivity. Our team participated in the seven ASCENDS science flights during late July and August 2011. These flights were made over a wide variety of surface and cloud conditions near the US, including over the central valley of California, over several mountain ranges, over both broken and solid stratus cloud deck over the Pacific Ocean, snow patches on mountain tops, over thin and broken clouds above the US Southwest and Iowa, and over forests near the WLEF tower in Wisconsin. Analyses show the retrievals of lidar range and CO2 column absorption, as well as estimates of CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds and to stratus cloud tops. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption profile (averaged for 50 sec) matched the predicted profile to better than 1% RMS error for all flight altitudes. For 1 & 10 second averaging, the scatter in the retrievals was limited by signal shot noise (i.e. the signal photon count). Analysis to date shows the decrease in CO2 due to vegetation when flying easterward over the Great Plains as well as the increase in CO2 concentration in the vicinity of the coal-fired power plant in New Mexico. Examples of these and other results will be presented.

Abshire, J. B.; Riris, H.; Allan, G. R.; Ramanathan, A.; Hasselbrack, W.; Mao, J.; Weaver, C. J.; Browell, E. V.

2012-12-01

44

Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption in the ASCENDS 2011 Airborne Campaign  

NASA Technical Reports Server (NTRS)

We have previously demonstrated an efficient pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. Our team participated in the 2010 ASCENDS airborne campaigns we flew airborne version of the CO2 and O2 lidar on the NASA DC-8. The CO2 lidar measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line using 250 mW average laser power, 30 wavelength samples per scan and 300 scans per second. Most flights had 5-6 altitude steps to greater than 12 km, and clear CO2 line shapes were observed at all altitudes. Our post-flight analysis estimated the Iidar range and pulse energies at each wavelength every second. We then solved for the best-fit CO2 absorption line shape, and calculated the Differential Optical Depth (DOD) at the line peak. We compared these to CO2 DODs calculated from spectroscopy based on HITRAN 2008 and the conditions from airborne in-situ readings. Analysis of the 2010 measurements over the Pacific Ocean and Lamont OK shows the expected -linear change of the peak DOD with altitude. For measurements at altitudes greater than 6 km the random errors were approximately 0.3 ppm for 80 sec averaging times. After the 2010 flights we improved the airborne lidar's scan uniformity, calibration and receiver sensitivity. Our team participated in the seven ASCENDS science flights during late July and August 2011. These flights were made over a wide variety of surface and cloud conditions near the US, including over the central valley of California, over several mountain ranges, over both broken and solid stratus cloud deck over the Pacific Ocean, snow patches on mountain tops, over thin and broken clouds above the US Southwest and Iowa, and over forests near the WLEF tower in Wisconsin. Analyses show the retrievals of lidar range and CO2 column absorption, as wen as estimates of CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds and to stratus cloud tops. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption profile (averaged for 50 sec) matched the predicted profile to better than 1% RMS error for all flight altitudes. For 1 & 10 second averaging, the scatter in the retrievals was limited by signal shot noise (i.e. the sigual photon count). Analysis to date shows the decrease in CO2 due to vegetation when flying easterward over the Great Plains as well as the increase in CO2 concentration in the vicinity ofthe coal-fired power plant in New Mexico. Examples of these and other results will be presented.

Abshire, James B.; Riris, Haris; Allan, Graham R.; Ramanathan, Anand; Hasselbrack, William E.; Mao, Jianping; Weaver, Clark; Browell, Edward V.

2012-01-01

45

Quantitation of promethazine and metabolites in urine samples using on-line solid-phase extraction and column-switching  

NASA Technical Reports Server (NTRS)

A chromatographic method for the quantitation of promethazine (PMZ) and its three metabolites in urine employing on-line solid-phase extraction and column-switching has been developed. The column-switching system described here uses an extraction column for the purification of PMZ and its metabolites from a urine matrix. The extraneous matrix interference was removed by flushing the extraction column with a gradient elution. The analytes of interest were then eluted onto an analytical column for further chromatographic separation using a mobile phase of greater solvent strength. This method is specific and sensitive with a range of 3.75-1400 ng/ml for PMZ and 2.5-1400 ng/ml for the metabolites promethazine sulfoxide, monodesmethyl promethazine sulfoxide and monodesmethyl promethazine. The lower limits of quantitation (LLOQ) were 3.75 ng/ml with less than 6.2% C.V. for PMZ and 2.50 ng/ml with less than 11.5% C.V. for metabolites based on a signal-to-noise ratio of 10:1 or greater. The accuracy and precision were within +/- 11.8% in bias and not greater than 5.5% C.V. in intra- and inter-assay precision for PMZ and metabolites. Method robustness was investigated using a Plackett-Burman experimental design. The applicability of the analytical method for pharmacokinetic studies in humans is illustrated.

Song, Q.; Putcha, L.; Harm, D. L. (Principal Investigator)

2001-01-01

46

Determination of phenylenediamine isomers in hair dyes by coal cinders micro-column extraction and MEKC.  

PubMed

A new micellar electrokinetic chromatography (MEKC) method using beta-cyclodextrins (?-CDs) and 1-butyl-3-methylimidazolium hexafluorophosphates (ionic liquids) as additives was successfully developed for determination of para-, meta-, and ortho-phenylenediamines isomers (p-P, m-P, and o-P) in hair dyes. To improve the sensitivity of the MEKC-UV, a simple and cheap flow injection (FI) technique using a micro-column packed with coal cinders (the by-products from combustion in a boiler) as solid-phase extractant was also investigated. In the presence of 20 mmol L(-1) phosphates at pH 5.5, addition of 12 mmol L(-1) ionic liquids and 8 mmol L(-1) ?-CDs greatly improved the separation efficiency. The three analytes could be quantitatively adsorbed by coal cinders, and desorbed readily with 0.15 mL of 0.01 mol L(-1) NaOH. Under the optimum conditions, an enrichment factor (EF) of 33.3 was obtained, and determination limits of p-P, m-P, and o-P were 1.97?×?10(-7), 0.99?×?10(-7), and 0.61?×?10(-7) mol L(-1), respectively. The adsorption capacities of the coal cinders micro-column for p-P, m-P, and o-P were all 1.20 mg g(-1). The presented procedure was successfully applied to the determination of p-P, m-P, and o-P in hair dyes with satisfactory results. PMID:21475944

Wu, Yiwei; Jiang, Feng; Chen, Lin; Zheng, Jing; Deng, Zhenli; Tao, Qing; Zhang, Jing; Han, Lijuan; Wei, Xiaoshu; Yu, Aimin; Zhang, Haili

2011-06-01

47

Development of an analytical method for yam saponins using HPLC with pulsed amperometric detection at different column temperatures.  

PubMed

Yam saponins (dioscin, gracillin, protodioscin, and protogracillin) were analyzed with three different C18 columns at incremental column temperatures from 15 to 45°C to investigate the effect of temperature on the retention and resolution of yam saponins. At low temperature, yam saponins showed decreased retention times and improved resolutions in the C18 columns. In the Kinetex C18 column at 15°C, the four saponins achieved baseline separation (Rs > 1.5) within 30 min. Pulsed amperometric detection was used to identify saponins with high sensitivity. The limits of detection and quantification of saponins were 0.11-0.31 and 0.33-0.95 ng, respectively. The correlation coefficients ranged 0.9986-1.0000. Intra- and inter-day precisions were <4.2% of retention times and <9.5% of the calculated contents. Average recoveries ranged from 92.18 to 105.98%. Saponin contents in Dioscorea nipponica tubers and commercial yam foods were determined without sample purification or concentration. Among the ten commercial yam foods investigated, only three showed significant saponin contents. PMID:23303619

Kwon, Ha-Jeong; Choi, Seung-Hee; Yoo, Chang-Seon; Choi, Hwa-Young; Lee, Soo-Eon; Park, Yong-Duk

2013-02-01

48

Flooding rates and holdup in packed liquid--liquid extraction columns  

Microsoft Academic Search

Countercurrent flow of liquids in columns packed with Raschig rings was studied with fluids having a wide range of physical properties. These results, along with data reported previously from other studies, were used to develop a correlation for predicting flooding rates in packed columns that is significantly better than previous correlations. Dispersed phase holdup in packed columns can be estimated

J. S. Watson; L. E. McNeese; John Day; P. A. Carroad

1975-01-01

49

Column silylation method for determining endocrine disruptors from environmental water samples by solid phase micro-extraction  

Microsoft Academic Search

In solid phase micro-extraction (SPME), the analyte is partitioned between the coating and the sample and then desorption of the concentrated analyte is followed by GC-MS, where the analytes are thermally desorbed and subsequently separated on the column and quantified by the detector. The SPME method preserves all the advantages, such as simplicity, low cost, on site sampling and does

Murad I. H Helaleh; S Fujii; T Korenaga

2001-01-01

50

Development of an automated synthesis system for preparation of glucuronides using a solid-phase extraction column loaded with microsomes.  

PubMed

An automated synthesis system using a solid-phase extraction (SPE) system and column packed with octadecylsilica (ODS), which was coated with phospholipid and loaded with dog liver microsomes, was developed for synthesis of glucuronides. Preparation of the microsome-immobilized SPE column, glucuronidation of drugs to synthesize the glucuronides and elution of the products were performed by an automated synthesis system. The phospholipid-coated SPE column and then the microsome-immobilized SPE column were readily prepared by allowing a solution containing L-alpha-dipalmitoylphosphatidylcholine to flow through the SPE column, and then by recycling a buffer solution containing dog liver microsomes through the resulting phospholipid-coated SPE column. The microsome-immobilized SPE column exhibiting the uridine diphosphate (UDP)-glucuronosyltransferase activity catalyzed the glucuronidation of mefenamic acid and estradiol to the corresponding glucuronides in the presence of UDP-glucuronic acid, and three glucuronides of mefenamic acid and estradiol were synthesized using the automated synthesis system, by simply recycling a buffer solution containing UDP-glucuronic acid through the microsome-immobilized SPE column loaded with the substrate. We used beta-cyclodextrin as a solubilizing agent for the synthesis of the glucuronides of estradiol that is practically insoluble in aqueous solutions. The productivity of these glucuronides using the microsome-immobilized SPE column was higher than that using the free microsomes (batch method). Furthermore, we developed a fully automated synthesis-isolation system by coupling the automated synthesis system to an automated preparative HPLC system. The automated synthesis system as well as the fully automated synthesis-isolation system should be very useful for synthesizing glucuronides for drug development. PMID:20190440

Kashima, Yousuke; Kitade, Takashi; Kashima, Yuuko; Okabayashi, Yoshito

2010-03-01

51

Automatic Vertebral Column Extraction by Whole-Body Bone SPECT Scan  

PubMed Central

Bone extraction and division can enhance the accuracy of diagnoses based on whole-body bone SPECT data. This study developed a method for using conventional SPECT for automatic recognition of the vertebral column. A novel feature of the proposed approach is a novel “bone graph" image description method that represents the connectivity between these image regions to facilitate manipulation of morphological relationships in the skeleton before surgery. By tracking the paths shown on the bone graph, skeletal structures can be identified by performing morphological operations. The performance of the method was evaluated quantitatively and qualitatively by two experienced nuclear medicine physicians. Datasets for whole-body bone SPECT scans in 46 lung cancer patients with bone metastasis were obtained with Tc-99m MDP. The algorithm successfully segmented vertebrae in the thoracolumbar spine. The quantitative assessment shows that the segmentation method achieved an average TP, FP, and FN rates of 95.1%, 9.1%, and 4.9%. The qualitative evaluation shows an average acceptance rate of 83%, where the data for the acceptable and unacceptable groups had a Cronbach's alpha value of 0.718, which indicated reasonable internal consistency and reliability.

Huang, Sheng-Fang; Chao, Hao-Yu; Kao, Pan-Fu; Shen, Wei-Chih; Chou, Yu-Hsiang; Liu, Shu-Hsin

2013-01-01

52

Determination of commonly used herbicides in surface water using solid-phase extraction and dual-column HPLC-DAD.  

PubMed

The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C(18)) Empore extraction disks, octadecyl (C(18)), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C(18) and CN) to confirm identification. Analytical separation was performed simultaneously on C(18) and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C(18) disks, from 75.1% to 100.0% for C(18) cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025--0.4 microg L(-1). The limits of detection were 0.012--0.035 microg L(-1). PMID:16194920

Ozhan, Gül; Ozden, Sibel; Alpertunga, Buket

2005-01-01

53

Method for making a non-extractable stationary phase of polymer within a capillary column  

DOEpatents

A method for coating interior capillary column surfaces, or packing material of a packed column, used for gas chromatography, with a stationary polymer phase that is cross-linked by exposing it to a low-temperature plasma that is uniformly distributed over the column or packing material for a predetermined period of time to effect the desired degree of cross-linking of the coating.

Springston, Stephen R. (Middle Island, NY)

1990-01-01

54

Method for making a non-extractable stationary phase of polymer within a capillary column  

DOEpatents

A method is described for coating interior capillary column surfaces, or packing material of a packed column, used for gas chromatography, with a stationary polymer phase that is cross-linked by exposing it to a low-temperature plasma that is uniformly distributed over the column or packing material for a predetermined period of time to effect the desired degree of cross-linking of the coating. 7 figs.

Springston, S.R.

1990-10-30

55

Comparative study between extraction techniques and column separation for the quantification of sinigrin and total isothiocyanates in mustard seed.  

PubMed

Glucosinolates are ?-thioglycosides which are found naturally in Cruciferae including the genus Brassica. When enzymatically hydrolysed, glucosinolates yield isothiocyanates and give a pungent taste. Both glucosinolates and isothiocyanates have been linked with anticancer activity as well as antifungal and antibacterial properties and therefore the quantification of these compounds is scientifically important. A wide range of literature exists on glucosinolates, however the extraction and quantification procedures differ greatly resulting in discrepancies between studies. The aim of this study was therefore to compare the most popular extraction procedures to identify the most efficacious method and whether each extraction can also be used for the quantification of total isothiocyanates. Four extraction techniques were compared for the quantification of sinigrin from mustard cv. Centennial (Brassica juncea L.) seed; boiling water, boiling 50% (v/v) aqueous acetonitrile, boiling 100% methanol and 70% (v/v) aqueous methanol at 70 °C. Prior to injection into the HPLC, the extractions which involved solvents (acetonitrile or methanol) were freeze-dried and resuspended in water. To identify whether the same extract could be used to measure total isothiocyanates, a dichloromethane extraction was carried out on the sinigrin extracts. For the quantification of sinigrin alone, boiling 50% (v/v) acetonitrile was found to be the most efficacious extraction solvent of the four tested yielding 15% more sinigrin than the water extraction. However, the removal of the acetonitrile by freeze-drying had a negative impact on the isothiocyanate content. Quantification of both sinigrin and total isothiocyanates was possible when the sinigrin was extracted using boiling water. Two columns were compared for the quantification of sinigrin revealing the Zorbax Eclipse to be the best column using this particular method. PMID:22743340

Cools, Katherine; Terry, Leon A

2012-07-15

56

Analysis of Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption from 3-13 km Altitudes  

NASA Technical Reports Server (NTRS)

We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS space mission [1]. It uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1575 nm band, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are precisely stepped in wavelength across the CO2 line and an O2 line region during the measurement. The direct detection receiver measures the energies of the laser echoes from the surface along with the range profile of scattering in the path. The column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off-line signals via the integrated path differential absorption (IPDA) technique. The time of flight of the laser pulses is used to estimate the height of the scattering surface and to reject laser photons scattered in the atmosphere. We developed an airborne lidar to demonstrate an early version of the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar stepped the pulsed laser's wavelength across the selected CO2 line with 20 wavelength steps per scan. The line scan rate is 450 Hz, the laser pulse widths are 1 usec, and laser pulse energy is 24 uJ. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a NIR photomultiplier and is recorded on every other reading by a photon counting system [2]. During August 2009 we made a series of 2.5 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over locations in the US, including the SGP ARM site in Oklahoma, central Illinois, north-eastern North Carolina, and over the Chesapeake Bay and the eastern shore of Virginia. Although the received signal energies were weaker than expected for ASCENDS, clear CO2 line shapes were observed at all altitudes, and some measurements were made through thin clouds. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, and in-situ measurements were made using its CO2 sensor and radiosondes. We have conducted an analysis of the ranging and IPDA lidar measurements from these four flights. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We used a cross-correlation approach to process the laser echo records. This was used to estimate the range to the scattering surface, to define the edges of the laser pulses and to determine echo pulse energy at each wavelength. We used a minimum mean square approach to fit an instrument response function and to solve for the best-fit CO2 absorption line shape. We then calculated the differential optical depth (DOD) of the fitted CO2 line. We computed its statistics at the various altitude steps, and compare them to the DODs calculated from spectroscopy based on HITRAN 2008 and the column conditions calculated from the airborne in-situ readings. The results show the lidar and in-situ measurements have very similar DOD change with altitude and greater than 10 segments per flight where the scatter in the lidar measurements are less than or equal to 1ppm. We also present the results from subsequent CO2 column absorption measurements, which were made with stronger detected signals during three flights on the NASA DC-8 over the southwestern US in during July 2010.

Abshire, James B.; Weaver, Clark J.; Riris, Haris; Mao, Jianping; Sun, Xiaoli; Allan, Graham R.; Hasselbrack, William; Browell, Edward V.

2011-01-01

57

Enhanced Extraction from Solid Foods and Biosuspensions by Pulsed Electrical Energy  

Microsoft Academic Search

The purpose of this article is to review matters dealing with application of electrical pulsed energy (pulsed electric field,\\u000a pulsed ohmic heating and high voltage electrical discharges) for enhancing the solid–liquid extraction in the food industry.\\u000a The quality of products (e.g., purity, color, texture, flavor and nutritients) extracted from solid foods (sugar beets, apples,\\u000a grapes, etc.) and quality of proteins

Eugene Vorobiev; Nikolai Lebovka

2010-01-01

58

Optimization of betulin extraction process from Inonotus Obliquus with pulsed electric fields  

Microsoft Academic Search

In this work, the extraction of betulin from Inonotus Obliquus applying high intensity pulsed electric fields (PEF) was studied. To extract non-polar compound, 75% ethanol solution was used. The effect of PEF on betulin yield was discussed compared with conventional extracting method. A set of optimal parameters (PEF strength=40 kV\\/cm, pulse number=2, ethanol concentration=75%, and solid-to-solvent ratio=1:25) were tested and analyzed.

Yongguang Yin; Yanru Cui; Hongwei Ding

2008-01-01

59

Capillary-based solid-phase extraction with columns prepared using different bead trapping methods.  

PubMed

Three approaches of bead immobilization for CEC column preparation in a capillary were examined for SPE. The three approaches included a packed column with a single frit, a packed column with an inlet and outlet frit, and an entrapped column where beads were immobilized within an organic polymer. A direct comparison of SPE/preconcentration of 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene and 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid with a 2 cm long bed showed that the entrapped column yielded the best performance in terms of reproducibility and robustness. The room temperature chemistry utilized to form the entrapped column enables the column to be photopatterned anywhere within the capillary without loss in bead functionality, and effectively links individual beads to one another at specific bead-bead and bead-capillary contact points. A 0.5 cm long entrapped bed exhibits high mechanical strength and is able to withstand >4400 psi. The entrapped bed was used to preconcentrate progesterone and beta-estradiol providing signal enhancements of >600. Following preconcentration, the hormones could be separated using CEC. With the current availability of numerous well-characterized chromatographic packing materials and the relative simplicity of the fabrication method, this methodology can be readily adapted to HPLC, CEC, and micro total analysis system. PMID:16200527

Xie, Ruixi; Oleschuk, Richard

2005-11-01

60

Short time ion pulse extraction from the Dresden electron beam ion trap.  

PubMed

We present measurements of the extraction of short time pulses of highly charged ions (4 keV, Ar(16+)) from the Dresden electron beam ion trap. Thereby the dependence of the extractable ionic charge on the extraction regime was investigated. The ion extraction time was varied between 20 ns and 1 micros. Furthermore the production of carbon ions and the influence of the extraction regime on the pulse widths was investigated to obtain information about the suitability of the Dresden EBIS-A in synchrotron based particle therapy facilities. PMID:20192362

Kentsch, U; Zschornack, G; Schwan, A; Ullmann, F

2010-02-01

61

Development of immunoaffinity columns for pyraclostrobin extraction from fruit juices and analysis by liquid chromatography with UV detection.  

PubMed

Pyraclostrobin belongs to a new generation of fungicides widely used to preserve high valuable crops. In the present study, three monoclonal antibodies with different affinities to this modern strobilurin have been evaluated for their usefulness in the production of immunoaffinity columns suitable for the solid-phase extraction, concentration, and clean-up of residues from food commodities. Different immunosorbents were produced and characterized in terms of antibody immobilization efficiency, immunosorbent binding capacity, optimum elution conditions, and reusability. Covalent coupling of the antibodies to Sepharose-CNBr gel took place with high yield (over 90%), whereas the immunosorbent efficacy to retain the analyte (from 28 to 68%) was shown to depend on the amount and type of antibody immobilized on the support. As a matter of fact, columns prepared with the monoclonal antibody PYs5#14 were able to selectively bound up to 53 ?g of pyraclostrobin per gram of beads. Acetonitrile solutions were preferred over methanolic ones for analyte elution, and some immunosorbents could be reused at least 4-6 times provided that the amount of pyraclostrobin and the volume of sample did not overload the column. Effectiveness of the selected immunoaffinity column was evidenced by the development of an extraction procedure for pyraclostrobin residues from fruit juices and further determination by high-performance liquid chromatography with UV detection. A concentration factor of 50 times was achieved with the developed immunoaffinity column, which eventually resulted in a limit of quantification of 0.01 mg L(-1). Finally, quantitative recoveries were obtained on apple juice and red grape must samples spiked with pyraclostrobin from 0.01 to 1 mg L(-1). PMID:21477805

Esteve-Turrillas, Francesc A; Mercader, Josep V; Agulló, Consuelo; Abad-Somovilla, Antonio; Abad-Fuentes, Antonio

2011-07-29

62

Simultaneous micro steam distillation\\/solvent extraction for the isolation of semivolatile flavor compounds from cinnamon and their separation by series coupled-column gas chromatography  

Microsoft Academic Search

Simultaneous micro steam distillation\\/solvent extraction is an efficient method of extracting semivolatile flavor and fragrance compounds from cinnamon for subsequent separation by series coupled-column gas chromatography. With pentane as the extraction solvent and an extraction time of 1.5 h clean extracts requiring no further sample preparation prior to gas Chromatographic analysis are obtained. It is shown that adulteration of cinnamon

Arya Jayatilaka; Salwa K. Poole; Colin F. Poole; Tina M. P. Chichila

1995-01-01

63

Physical versus chemical effects on bacterial and bromide transport as determined from on site sediment column pulse experiments  

SciTech Connect

Twenty eight bacterial and Br transport experiments were performed in the field to determine the effects of physical and chemical heterogeneity of the aquifer sediment. The experiments were performed using groundwater from two field locations to examine the effects of groundwater chemistry on transport. Groundwater was extracted from multilevel samplers and pumped through 7 cm long columns of intact sediment or re-packed sieved and coated or uncoated sediment from the underlying aquifer. Two bacterial strains, Comamonas sp. DA001 and Paenibacillus polymyxa FER-02, were injected along with Br into the influent end of the columns to examine the effect of cell morphology and surface properties on bacterial transport. The effect of column sediment grain size and mineral coatings coupled with groundwater geochemistry were also delineated. Significant irreversible attachment of DA001 was observed in the Fe oxyhydroxide coated columns, but only in the sub-oxic groundwater where the concentrations of dissolved organic carbon (DOC) were ca. 1 ppm. In the oxic groundwater where DOC was ca. 8 ppm, little attachment of DA001 to the Fe oxyhydroxide coated columns was observed. This indicates that DOC can significantly reduce bacterial attachment due electrostatic interactions. The larger and more negatively charged FER-02 displayed increasing attachment with decreasing grain size regardless of DOC concentration, and modeling of FER-02 attachment revealed that the presence of Fe and Al coatings on the sediment also promoted attachment. Finally, the presence of Al coatings and Al containing minerals appeared to significantly retard the Br tracer regardless of the concentration of DOC. These findings suggest that DOC in shallow oxic groundwater aquifers can significantly enhance the transport of bacteria by reducing attachment to Fe, Mn and Al oxyhydroxides. This effect is profound for weakly charged, hydrophilic bacteria and may contribute to differences in observations between laboratory experiments verses field-scale investigations particularly if the groundwater pH remains circum-neutral and Fe oxyhydroxide phases exist. These observations validate the novel approach taken in the experiments outlined here of performing laboratory-scale experiments on site to facilitate the use of fresh groundwater and thus be more representative of in situ groundwater conditions.

Hall, James A.; Mailloux, Brian J.; Onstott, Tullis C.; Scheibe, Timothy D.; Fuller, Mark E.; Dong, Hailiang; Deflaun, Mary F.

2005-02-01

64

Physical versus chemical effects on bacterial and bromide transport as determined from on site sediment column pulse experiments  

NASA Astrophysics Data System (ADS)

Twenty-eight bacterial and Br transport experiments were performed in the field to determine the effects of physical and chemical heterogeneity of the aquifer sediment. The experiments were performed using groundwater from two field locations to examine the effects of groundwater chemistry on transport. Groundwater was extracted from multilevel samplers and pumped through 7-cm-long columns of intact sediment or repacked sieved and coated or uncoated sediment from the underlying aquifer. Two bacterial strains, Comamonas sp. DA001 and Paenibacillus polymyxa FER-02, were injected along with Br into the influent end of columns to examine the effect of cell morphology and cell surface properties on bacterial transport. The effects of column sediment grain size and mineral coatings coupled with groundwater geochemistry were also investigated. Significant irreversible attachment of DA001 was observed in the Fe oxyhydroxide-coated columns, but only in the suboxic groundwater where the concentrations of dissolved organic carbon (DOC) were ca. 1 ppm. In the oxic groundwater where DOC was ca. 8 ppm, little attachment of DA001 to the Fe oxyhydroxide-coated columns was observed. This indicates that DOC can significantly reduce bacterial attachment due electrostatic interactions. The larger and more negatively charged FER-02 displayed increasing attachment with decreasing grain size regardless of DOC concentration, and modeling of FER-02 attachment revealed that the presence of Fe and Al coatings on the sediment also promoted attachment. Finally, the presence of Al coatings and Al containing minerals appeared to significantly retard the Br tracer regardless of the concentration of DOC. These findings suggest that DOC in shallow oxic groundwater aquifers can significantly enhance the transport of bacteria by reducing attachment to Fe, Mn and Al oxyhydroxides. This effect appears to be profound for weakly and strongly charged hydrophilic bacteria and may contribute to differences in observations between laboratory experiments versus field-scale investigations particularly if the groundwater pH remains subneutral and Fe oxyhydroxide phases exist. These observation validate the novel approach taken in the experiments outlined here of performing laboratory-scale experiments on site to facilitate the use of fresh groundwater and thus be more representative of in situ groundwater conditions.

Hall, J. A.; Mailloux, B. J.; Onstott, T. C.; Scheibe, T. D.; Fuller, M. E.; Dong, H.; DeFlaun, M. F.

2005-02-01

65

Capillary monolithic titania column for miniaturized liquid chromatography and extraction of organo-phosphorous compounds.  

PubMed

A new sol-gel protocol was designed and optimized to produce titanium-dioxide-based columns within confined geometries such as monolithic capillary columns and porous-layer open-tubular columns. A surface pre-treatment of the capillary enabled an efficient anchorage of the monolith to the silica capillary wall during the synthesis. The monolith was further synthesized from a solution containing titanium n-propoxide, hydrochloric acid, N-methylformamide, water, and poly(ethylene oxide) as pore template. The chromatographic application of capillary titania-based columns was demonstrated with the separation of a set of phosphorylated nucleotides as probe molecules using aqueous normal-phase liquid chromatography conditions. Capillary titania monoliths offered a compromise between the high permeability and the important loading capacity needed to potentially achieve miniaturized sample preparations. The specificity of the miniaturized titania monolithic support is illustrated with the specific enrichment of 5'-adenosine mono-phosphate. The monolithic column offered a ten times higher loading capacity of 5'-adenosine mono-phosphate compared with that of the capillary titania porous-layer open-tubular geometry. PMID:21331495

Abi Jaoudé, Maguy; Randon, Jérôme

2011-05-01

66

Pulse Profiles, Accretion Column Dips and a Flare in GX 1+4 During a Faint State  

NASA Technical Reports Server (NTRS)

The Rossi X-ray Timing Explorer (RXTE) spacecraft observed the X-ray GX 1+4 for it period of 34 hours on July 19/20 1996. The source faded front an intensity of approximately 20 mcrab to a minimum of <= 0.7 mcrab and then partially recovered towards the end of the observation. This extended minimum lasted approximately 40,000 seconds. Phase folded light curves at a barycentric rotation period of 124.36568 +/- 0.00020 seconds show that near the center of the extended minimum the source stopped pulsing in the traditional sense but retained a weak dip feature at the rotation period. Away from the extended minimum the dips are progressively narrower at higher energies and may be interpreted as obscurations or eclipses of the hot spot by the accretion column. The pulse profile changed from leading-edge bright before the extended minimum to trailing-edge bright after it. Data from the Burst and Transient Source Experiment (BATSE) show that a torque reversal occurred < 10 days after our observation. Our data indicate that the observed rotation departs from a constant period with a P/P value of approximately -1.5% per year at a 4.5sigma significance. We infer that we may have serendipitously obtained data, with high sensitivity and temporal resolution about the time of an accretion disk spin reversal. We also observed a rapid flare which had some precursor activity close to the center of the extended minimum.

Giles, A. B.; Galloway, D. K.; Greenhill, J. G.; Storey, M. C.; Wilson, C. A.

1999-01-01

67

Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes  

NASA Technical Reports Server (NTRS)

We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's planned ASCENDS space mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1570 nm band, O2 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are rapidly and precisely stepped in wavelength across the CO2 line and an O2 line region during the measurement. The direct detection receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. The time of flight of the laser pulses are also used to estimate the height of the scattering surface and to identify cases of mixed cloud and ground scattering. We have developed an airborne lidar to demonstrate the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar steps the pulsed laser's wavelength across the selected CO2 line with 20 steps per scan. The line scan rate is 450 Hz, the laser pulse widths are 1 usec, and laser pulse energy is 24 uJ. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during fall 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin clouds. The atmospheric CO2 column measurements using the 1572.33 nm CO2 lines. Two flights were made above the US Department of Energy's (DOE) SGP ARM site at altitudes from 3-8 km. These flights were coordinated with DOE investigators who flew an in-situ CO2 sensor on a Cessna aircraft under the path. The increasing CO2 line absorptions with altitudes were evident and comparison with in-situ measurements showed agreements to 6 ppm. In spring 2009 we improved the aircraft's nadir window and during July and August we made 9 additional 2 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over a variety of surface types in Nebraska, Illinois, the SGP ARM site, and near and over the Chesapeake Bay in North Carolina and eastern Virginia. Strong laser signals and clear CO2 line shapes were observed at all altitudes, and some measurements were made through thin clouds. The flights over the ARM site were underflown with in-situ measurements made from the DOE Cessna. Analysis shows that the average signal levels follow predicted values, the altimetry measurements had an uncertainty of about 4 m, and that the average optical line depths follow the number density calculated from in-situ sensor readings. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, a LaRC in-situ CO2 sensor, and the Oklahoma flights also included a JPL CO2 lidar on a Twin Otter aircraft. More details of the flights, measurements, analysis and scaling to space will be described in the presentation.

Abshire, James; Riris, Haris; Allan, Graham; Weaver, Clark; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William

2010-01-01

68

Development of the repetitive pulsed power system for spallation neutron source beam extraction fast kicker  

Microsoft Academic Search

The spallation neutron source (SNS) is a next-generation high-intensity beam facility. The extraction kicker system is a high peak power, high average power, high-precision pulse-waveform, low beam impedance, and high repetition rate pulsed power system. It has been successfully designed and developed at Brookhaven National Laboratory, Upton, NY. The system consists of fourteen extraction magnet sections inside the ring vacuum

W. Zhang; Jon Sandberg; Roy Cutler; H. Hahn; R. Lambiase; Y. Y. Lee; J. Mi; T. Nehring; C. Pai; K. Rust; N. Tsoupas; J. Tuozzolo; D. Warburton; Jie Wei; S. Y. Zhang

2004-01-01

69

HYDRODYNAMICS OF A NONAQUEOUS SYSTEM IN A PACKED LIQUID EXTRACTION COLUMN  

Microsoft Academic Search

Dispersed phase holdup, flood point and droplet size data have been obtained for the effectively non-aqueous system Sulfolane-heptane in a 75 mm diameter column packed with random Raschig rings. The holdup results showed distinctly different behaviour from that of aqueous systems, giving a characteristic velocity plot that was concave upwards, indicating an increasing droplet velocity at higher holdup values. The

Richard J. Moore; H. R. Clive Pratt; Geoffrey W. Stevens

1989-01-01

70

Enhancement of the extraction of betanine from red beetroot by pulsed electric fields  

Microsoft Academic Search

A systematic study about the influence of pulsed electric fields (PEF) and other operating parameters on betanine extraction from red beetroots has been carried out in this investigation. Thin disks of red beetroots were subjected to PEF at different intensities (number of pulses and field strengths), and the release of betanine into media of different pH and at different temperatures

Noelia López; Eduardo Puértolas; Santiago Condón; Javier Raso; Ignacio Alvarez

2009-01-01

71

Determination of myo-inositol (free and bound as phosphatidylinositol) in infant formula and adult nutritionals by liquid chromatography/pulsed amperometry with column switching: first action 2011.18.  

PubMed

Myo-inositol is a 6-carbon cyclic polyalcohol also known as meso-inositol, meat sugar, inosite, and i-inositol. It occurs in nature in both free (myo-inositol) and bound (inositol phosphates and phosphatidylinositol) forms. For the determination of free myo-inositol, samples are mixed with dilute hydrochloric acid to extract myo-inositol and precipitate proteins, diluted with water, and filtered. For the determination of myo-inositol bound as phosphatidylinositol, samples are extracted with chloroform, isolated from other fats with silica SPE cartridges, and hydrolyzed with concentrated acid to free myo-inositol. Prepared samples are first injected onto a Dionex CarboPac PA1 column, which separates myo-inositol from other late-eluting carbohydrates. After column switching, myo-inositol is further separated on a CarboPac MA1 column using a 0.12% sodium hydroxide mobile phase; strongly retained carbohydrates are eluted from the PA1 column with a 3% sodium hydroxide mobile phase. Eluant from the CarboPac MA1 analytical column passes through an electrochemical detector cell where myo-inositol is detected by pulsed amperometry using a gold electrode. The method showed appropriate performance characteristics versus selected established standard method performance requirement parameters for the determination of myo-inositol: linear response; repeatability (RSDr) of 2%; and intermediate precision (RSDir) of 2.5%. Instrument LOD and LOQ were 0.0004 and 0.0013 mg/100 mL, respectively, and correspond to a free myo-inositol quantitation limit of 0.026 mg/100 g and a phosphatidylinositol quantitation limit of 0.016 mg/100 g. Correlation with the reference microbiological assay was good. The proposed method has been accepted by the Expert Review Panel as an AOAC First Action Method, suitable for the routine determination of myo-inositol in infant formula and adult nutritionals. PMID:22970560

Schimpf, Karen; Thompson, Linda; Baugh, Steve

2012-01-01

72

Pulsed electric field treatment for solid–liquid extraction of red beetroot pigment  

Microsoft Academic Search

Extractability of red pigment from red beetroot was investigated using pulsed electric field (PEF) treated tissue in a solid–liquid extraction process. Thin disks of the tissue were subjected to PEF at different intensities and, 3–4 min after the treatment, the release of red pigment and ionic species into an isotonic solution was measured in situ using a spectrophotometer and a

Mustafa Fincan; Francesca DeVito; Petr Dejmek

2004-01-01

73

H- extraction from electron-cyclotron-resonance-driven multicusp volume source operated in pulsed mode  

NASA Astrophysics Data System (ADS)

H2 microwave (2.45 GHz) pulsed plasma is produced from seven elementary electron cyclotron resonance sources installed into the magnetic multipole chamber ``Camembert III'' (École Polytechnique-Palaiseau) from which H- extraction takes place. The negative-ion and electron extracted currents are studied through electrical measurements and the plasma parameters by means of electrostatic probe under various experimental conditions. The role of the plasma electrode bias and the discharge duty cycle in the extraction process is emphasized. The gas breakdown at the beginning of every pulse gives rise to variations of the plasma characteristic parameters in comparison with those established at the later time of the pulse, where the electron temperature, the plasma potential, and the floating potential converge to the values obtained for a continuous plasma. The electron density is significantly enhanced in the pulsed mode.

Svarnas, P.; Bacal, M.; Auvray, P.; Béchu, S.; Pelletier, J.

2006-03-01

74

Online micro-solid-phase extraction based on boronate affinity monolithic column coupled with high-performance liquid chromatography for the determination of monoamine neurotransmitters in human urine.  

PubMed

Quantification of monoamine neurotransmitters is very important in diagnosing and monitoring of patients with neurological disorders. We developed an online analytical method to selectively determine urinary monoamine neurotransmitters, which coupled the boronate affinity monolithic column micro-solid-phase extraction with high-performance liquid chromatography (HPLC). The boronate affinity monolithic column was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and N,N'-methylenebisacrylamide (MBAA) in a stainless capillary column. The prepared monolithic column showed good permeability, high extraction selectivity and capacity. The column-to-column reproducibility was satisfactory and the enrichment factors were 17-243 for four monoamine neurotransmitters. Parameters that influence the online extraction efficiency, including pH of sample solution, flow rate of extraction and desorption, extraction volume and desorption volume were investigated. Under the optimized conditions, the developed method exhibited low limit of detection (0.06-0.80?g/L), good linearity (with R(2) between 0.9979 and 0.9993). The recoveries in urine samples were 81.0-105.5% for four monoamine neurotransmitters with intra- and inter-day RSDs of 2.1-8.2% and 3.7-10.6%, respectively. The online analytical method was sensitive, accurate, selective, reliable and applicable to analysis of trace monoamine neurotransmitters in human urine sample. PMID:24703360

Yang, Xiaoting; Hu, Yufei; Li, Gongke

2014-05-16

75

[Fast determination of active components in Angelica dahurica extract using capillary electrochromatography with methacrylate ester-based monolithic columns].  

PubMed

The separation and determination of four important active components (imperatorin, isoimperatorin, phelloptorin and falcarindiol) from Angelica dahurica extract has been performed using capillary electrochromatography (CEC) with a methacrylate ester-based monolithic column. The effect of the porogen ratio on the column preparation was studied. The mobile phase composition, such as the concentration of organic solvent, the ionic strength and the pH of the buffer were also optimized. Under the optimized conditions (50% acetonitrile and 50% of a 20 mmol/L sodium dihydrogen phosphate electrolyte at pH 4.95, - 25 kV), a fast and baseline separation of the four analytes was achieved. The calibration curves showed a good linearity (r2 > 0.997) and the limits of detection were lower than 0.34 mg/L. The mean recoveries of the studied components ranged between 95.18% and 98.44%. The method developed is sensitive, reliable and suitable for the quality control. With this CEC system, the quality of Angelica dahurica extracts from 18 various regions was evaluated. PMID:20549974

Wang, Jiajing; Chen, Zhao; Wu, Yutian; Fan, Guorong

2010-03-01

76

Laser capture microdissection coupled with on-column extraction LC-MS(n) enables lipidomics of fluorescently labeled Drosophila neurons.  

PubMed

We have used laser capture microdissection (LCM) and fluorescence microscopy to isolate genetically labeled neurons from the Drosophila melanogaster brain. From native thin sections, regions of interest could be analyzed with a spatial resolution better than 50 ?m. To exploit the specificity of LCM for lipidomics, catapulted tissue patches were directly collected on a reversed phase column and analyzed using an on-column extraction (OCE) that was directly coupled with liquid chromatography-multistage mass spectrometry (LC-MS(n)). With this approach, more than 50 membrane lipids belonging to 9 classes were quantified in tissue regions equivalent to a sample amount of 50 cells. Using this method, the limit of quantitation and the extraction efficiency could be estimated enabling a reliable evaluation of acquired lipid profiles. The lipid profiles of cell body- and synapse-enriched regions of the Drosophila brain were determined and found to be distinct. We argue that this workflow represents a tremendous improvement for tissue lipidomics by integrating genetics, fluorescence microscopy, LCM and LC-MS(n). PMID:24820458

Hebbar, Sarita; Schulz, Wolf Dieter; Sauer, Ulrich; Schwudke, Dominik

2014-06-01

77

Determination of phenylenediamine isomers in hair dyes by coal cinders micro-column extraction and MEKC  

Microsoft Academic Search

A new micellar electrokinetic chromatography (MEKC) method using beta-cyclodextrins (?-CDs) and 1-butyl-3-methylimidazolium\\u000a hexafluorophosphates (ionic liquids) as additives was successfully developed for determination of para-, meta-, and ortho-phenylenediamines isomers (p-P, m-P, and o-P) in hair dyes. To improve the sensitivity of the MEKC-UV, a simple and cheap\\u000a flow injection (FI) technique using a micro-column packed with coal cinders (the by-products from

Yiwei Wu; Feng Jiang; Lin Chen; Jing Zheng; Zhenli Deng; Qing Tao; Jing Zhang; Lijuan Han; Xiaoshu Wei; Aimin Yu; Haili Zhang

2011-01-01

78

[Determination of free formaldehyde in cosmetics by pre-column derivatization, extraction inhibition and high performance liquid chromatography].  

PubMed

Pre-column derivatization and inhibition by solvent extraction were applied to determine free formaldehyde in cosmetics by high performance liquid chromatography (HPLC). Due to the rapid decomposition of formaldehyde donors in the derivatization, it is hard to detect the amount of the free formaldehyde in cosmetics. The formaldehyde directly reacted with 2,4-dinitrophenylhydrazine in acetonitrile-phosphate buffer (pH 2) (1:1, v/v) solution for 2 min, then dichloromethane extraction was used to induce the decomposition of formaldehyde donors. The extract was diluted with acetonitrile and then determined by HPLC. The formaldehyde derivative was separated on an Agilent C18 column (250 mm x 4.6 mm, 5 microm) at 30 degrees C with acetonitrile-water (60:40, v/v) as mobile phase at a flow rate of 1.0 mL/min, and detected at the wavelength of 355 nm. The recoveries were from 81% to 106% at the spiked levels of 50, 100, 500, 1 000 microg/g of formaldehyde in shampoo, milk, cream, hand cleaner, toothpaste, nail polish, powder separately, and the relative standard deviations (n = 6) were less than 5.0%. The limit of quantification of the formaldehyde in cosmetics was 50 microg/g. The method has been applied to the determination of free formaldehyde in real samples and the results showed that the release by formaldehyde donors was inhibited. The method has the advantages of simple operation, good accuracy and meets the requirement of determination of free formaldehyde in cosmetics. PMID:23593888

Lü, Chunhua; Huang, Chaoqun; Chen, Mei; Xie, Wen; Chen, Xiaomei

2012-12-01

79

Extraction of quadrature phase information from multiple pulse NMR signals  

NASA Technical Reports Server (NTRS)

A multiple pulse sequence (8-pulse sequence) used for high-resolution solid state NMR is analyzed with regard to the information available from each of the four wide sampling windows. It is demonstrated that full quadrature phase information can be obtained using only a single phase detector and that, for the commonly encountered situation where the spectral width is much less than the folding frequency, the signals from the various windows can be combined easily using standard complex Fourier transform software. An improvement in the signal-to-noise ratio equal to the square root of 3 is obtained over either standard single or quadrature phase detection schemes. Procedures for correcting spectral distortions are presented.

Rhim, W.-K.; Burum, D. P.; Vaughan, R. W.

1976-01-01

80

Direct extraction of coherent mode properties from imaging measurements in a linear plasma column  

SciTech Connect

Spectral properties of coherent waves in an argon plasma column are examined using fluctuation data from fast imaging. Visible light from ArII line emission is collected at high frame rates using a high-speed digital camera. A cross-spectral phase technique allows direct visualization of dominant phase structures as a function of frequency, as well as identification of azimuthal asymmetries present in the system. Experimental dispersion estimates are constructed from imaging data alone. Drift-like waves are identified by comparison with theoretical dispersion curves, and a tentative match of a low-frequency spectral feature to Kelvin-Helmholtz-driven waves is presented. Imaging measurements are consistent with previous results, and provide non-invasive, single-shot measurements across the entire plasma cross-section. Implications of the measured spectral properties for imaging measurements of mode dynamics are explored.

Light, A. D.; Sechrest, Y.; Munsat, T. [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States) [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States); Center for Integrated Plasma Studies, Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309 (United States); Thakur, S. C.; Brandt, C.; Tynan, G. R. [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States) [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States); Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)

2013-08-15

81

Determination of ricin by nano liquid chromatography/mass spectrometry after extraction using lactose-immobilized monolithic silica spin column.  

PubMed

Ricin is a glycosylated proteinous toxin that is registered as toxic substance by Chemical Weapons convention. Current detection methods can result in false negatives and/or positives, and their criteria are not based on the identification of the protein amino acid sequences. In this study, lactose-immobilized monolithic silica extraction followed by tryptic digestion and liquid chromatography/mass spectrometry (LC/MS) was developed as a method for rapid and accurate determination of ricin. Lactose, which was immobilized on monolithic silica, was used as a capture ligand for ricin extraction from the sample solution, and the silica was supported in a disk-packed spin column. Recovery of ricin was more than 40%. After extraction, the extract was digested with trypsin and analyzed by LC/MS. The accurate masses of molecular ions and MS/MS spectra of the separated peptide peaks were measured by Fourier transform-MS and linear iontrap-MS, respectively. Six peptides, which were derived from the ricin A-(m/z 537.8, 448.8 and 586.8) and B-chains (m/z 701.3, 647.8 and 616.8), were chosen as marker peptides for the identification of ricin. Among these marker peptides, two peptides were ricin-specific. This method was applied to the determination of ricin from crude samples. The monolithic silica extraction removed most contaminant peaks from the total ion chromatogram of the sample, and the six marker peptides were clearly detected by LC/MS. It takes about 5 h for detection and identification of more than 8 ng/ml of ricin through the whole handling, and this procedure will be able to deal with the terrorism using chemical weapon. PMID:21834021

Kanamori-Kataoka, Mieko; Kato, Haruhito; Uzawa, Hirotaka; Ohta, Shigenori; Takei, Yoshiyuki; Furuno, Masahiro; Seto, Yasuo

2011-08-01

82

A Column Experiment To Determine Black Shale Degradation And Colonization By Means of ?13C and 14C Analysis Of Phospholipid Fatty Acids And DNA Extraction  

NASA Astrophysics Data System (ADS)

We investigated the degradation of black shale organic matter by microbial communities. We inoculated two columns respectively, with the fungi Schizophyllum commune, the gram-positive bacterium Pseudomonas putida and the gram-negative bacteria Streptomyces griseus and Streptomyces chartreusis. These microorganisms are known to degrade a wide variety of organic macromolecules. Additionally, we had two sets of control columns. To one set the same nutrient solution was added as to the inoculated columns and to the other set only sterile deionised water was supplied. All columns contained 1.5 kg of freshly crushed not autoclaved black shale material with a particle size of 0.63-2 mm. The columns were incubated at 28° C and 60% humidity in the dark. The aim was to investigate, which microorganisms live on black shales and if these microorganisms are able to degrade ancient organic matter. We used compound specific stable isotope measurement techniques and compound specific 14C-dating methods. After 183 days PLFAs were extracted from the columns to investigate the microbial community, furthermore we extracted on one hand total-DNA of column material and on the other hand DNA from pure cultures isolates which grew on Kinks-agar B, Starch-casein-nitrate-agar (SCN) and on complete-yeast-medium-agar (CYM). According to the PLFA analysis bacteria dominated in the columns, whereas in pure cultures more fungi were isolated. A principal component analysis revealed differences between the columns in accordance with the inoculation, but it seems that the inoculated microorganisms were replaced by the natural population. For AMS measurements palmitic acid (C 16:0) was re-isolated from total-PLFA-extract with a preparative fraction collector (PFC). Preliminary results of the study revealed that microorganisms are able to degrade black shale material and that PLFA analysis are useful methods to be combined with analysis of stable isotope and 14C measurements to study microbial degradation processes.

Seifert, A.; Gleixner, G.

2008-12-01

83

Column Solid Phase Extraction of Copper, Iron, and Zinc Ions at Trace Levels in Environmental Samples on Amberlite XAD?7 for Their Flame Atomic Absorption Spectrometric Determinations  

Microsoft Academic Search

A column solid?phase extraction method for the separation and preconcentration of copper, zinc, and iron at trace levels has been established prior to their flame atomic absorption spectrometric determinations. Analytes from 0.5 M KSCN in a 1 M HCl solution were recovered using of an Amberlite XAD?7 column. The chemical variables affecting the analytical performance of the combined methodology including reagent amounts,

Mustafa Tuzen; Mustafa Soylak; Latif Elci; Mehmet Dogan

2004-01-01

84

Determination of berberine and palmatine in Phellodendri Cortex using ion-pair supercritical fluid chromatography on-line coupled with ion-pair supercritical fluid extraction by on-column trapping  

Microsoft Academic Search

An assay of berberine and palmatine in Phellodendri Cortex was established using ion-pair supercritical fluid chromatography (IP-SFC) on-line coupled with ion-pair supercritical fluid extraction (IP-SFE). The on-column method was employed to successfully perform on-line SFE-SFC. With a silica-gel column as a trapping and separation column, berberine and palmatine were extracted and focused at the column head, even if 10% methanol

Keiichi Suto; Shinichi Kakinuma; Yuji Ito; Kazuhiko Sagara; Hideki Iwasaki; Hideji Itokawa

1997-01-01

85

Monolithic spin column: a new extraction device for analysis of drugs in urine and serum by GC/MS and HPLC/MS.  

PubMed

A monolithic spin column was developed for the extraction of analytes from biological materials. This column was constructed by packing a monolithic silica disk into a spin column. Sample loading, washing, and elution of the target drugs were accomplished simply by centrifugation of the column. Opiates and benzodiazepines are abused throughout the world. Identification and quantification of these drugs is very important to solve crimes or the cause of death. Three opiates (morphine, codeine, and dihydrocodeine) were extracted from urine and serum by using the column. After conversion to trimethylsilyl derivatives of the opiates by vigorous mixing with the derivatizing reagent, the solution was subjected to GC/MS. A linear curve was observed for opiates from 10 to 2500 ng/mL in urine and 5 to 1200 ng/mL in serum, respectively (correlation coefficient > 0.996). For benzodiazepines, the hydroxyl metabolites of triazolam and etizolam were extracted from urine using the column, and the eluate was directly analyzed by HPLC/MS without evaporation. The LOD values were at the ppb level, with RSD values lower than 15%. The proposed methods were successfully applied to clinical and forensic cases, and good agreement of results was obtained compared to conventional methods. PMID:21797004

Namera, Akira; Nagao, Masakata; Nakamoto, Akihiro; Miyazaki, Shota; Saito, Takeshi

2011-01-01

86

Achievement of 100 s Long Pulse Neutral Beam Extraction in EAST Neutral Beam Injector  

NASA Astrophysics Data System (ADS)

Neutral beam injection (NBI) is recognized as one of the most effective means for plasma heating. A 100 s long pulse neutral beam with 30 keV beam energy, 10 A beam current and a 100 s long pulse modulating neutral beam with 50 keV beam energy, 16 A beam current were achieved in the EAST neutral beam injector on the test-stand. The preliminary results suggest that EAST-NBI system initially possess the ability of long pulse beam extraction.

Hu, Chundong; The NBI Team

2013-03-01

87

Rapid Column Extraction Method for Actinides and Sr-89/90 in Water Samples  

SciTech Connect

The SRS Environmental Laboratory analyzes water samples for environmental monitoring, including river water and ground water samples. A new, faster actinide and strontium 89/90 separation method has been developed and implemented to improve productivity, reduce labor costs and add capacity to this laboratory. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and Sr-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu), neptunium (Np), uranium (U), americium (Am), curium (Cm) and thorium (Th) using a single multi-stage column combined with alpha spectrometry. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized. The method can be used for routine analysis or as a rapid method for emergency preparedness. Thorium and curium are often analyzed separately due to the interference of the daughter of Th-229 tracer, actinium (Ac)-225, on curium isotopes when measured by alpha spectrometry. This new method also adds a separation step using DGA Resin{reg_sign}, (Diglycolamide Resin, Eichrom Technologies) to remove Ac-225 and allow the separation and analysis of thorium isotopes and curium isotopes at the same time.

MAXWELL III, SHERROD L.

2005-06-15

88

Use of online-dual-column extraction in conjunction with chiral liquid chromatography tandem mass spectrometry for determination of terbutaline enantiomers in human plasma.  

PubMed

An online sample extraction chiral bioanalytical method was developed and validated for the quantification of terbutaline, a beta2-selective adrenoceptor agonist, spiked into human plasma by using two extraction columns and a chiral stationary phase (CSP) in conjunction with liquid chromatography tandem mass spectrometry (LC-MS/MS). In this method, two Oasis HLB extraction columns were used in parallel for plasma sample purification and a Chirobiotic T CSP was used for enantiomeric separation. Atmospheric pressure chemical ionization MS/MS was employed in multiple reaction monitoring mode for the detection and quantification. Subsequent to the addition of an internal standard solution, the plasma samples were directly injected onto the system for extraction and analysis. This method allowed the use of one of the extraction columns for purification while the other was being equilibrated. Hence, the time required for reconditioning the extraction columns did not contribute to the total analysis time per sample, which resulted in a shorter run time and higher throughput. A lower limit of quantification of 1.0 ng/mL was achieved using only 50 microliter of human plasma. The method was validated with a dynamic range of 1.0-200 ng/mL. The intra- and interday precision was no more than 11% CV and the assay accuracy was between 94-106%. PMID:12237836

Xia, Yuan-Qing; Liu, David Q; Bakhtiar, Ray

2002-10-01

89

Enhanced anthocyanin extraction from red cabbage using pulsed electric field processing.  

PubMed

This study was conducted to evaluate the effect of pulsed electric field (PEF) treatment on anthocyanin extraction from red cabbage using water as a solvent. Mashed cabbage was placed in a batch treatment chamber and subjected to PEF (2.5 kV/cm electric field strength; 15 micros pulse width and 50 pulses, specific energy 15.63 J/g). Extracted anthocyanin concentrations (16 to 889 microg/mL) were determined using HPLC. Heat and light stabilities of the control and PEF-treated samples, having approximately the same initial concentrations, were studied. PEF treatments enhanced total anthocyanin extraction in water from red cabbage by 2.15 times with a higher proportion of nonacylated forms than the control (P < 0.05). The heat and light stabilities of the PEF-treated samples and control samples were not significantly different (P > 0.05). Practical Application: An innovative pretreatment technology, pulsed electric field processing, enhanced total anthocyanin extraction in water from red cabbage by 2.15 times. Manufacturers of natural colors can use this technology to extract anthocyanins from red cabbage efficiently. PMID:20722916

Gachovska, Tanya; Cassada, David; Subbiah, Jeyamkondan; Hanna, Milford; Thippareddi, Harshavardhan; Snow, Daniel

2010-08-01

90

Optimisation extraction of chondroitin sulfate from fish bone by high intensity pulsed electric fields.  

PubMed

High intensity pulsed electric fields (PEF) was used to extract chondroitin sulphate (CS) from fish bone. Results show that PEF extraction speed is much faster, and the content of CS is much higher compared with traditional methods. Variation of PEF parameters and the content of CS were determined by single factor experiments. The processing conditions were optimised by quadratic general rotary unitised design experiments. The maximum yield of 6.92g/L was achieved under the following conditions: material-liquid ratio of 1:15g/mL, electric field intensity of 16.88kV/cm, pulse number of 9, and NaOH concentration of 3.24%. The purity of CS was analysed by agarose gel electrophoresis. CS purity was high, and the extract did not contain any other glycosaminoglycans. PEF can be widely used to extract CS with non-thermal performance, high speed, and low pollution. PMID:24996325

He, Guidan; Yin, Yongguang; Yan, Xiaoxia; Yu, Qingyu

2014-12-01

91

Optimisation of pulsed ultrasonic and microwave-assisted extraction for curcuminoids by response surface methodology and kinetic study.  

PubMed

A response surface methodology and a kinetic study were used to optimise the pulsed ultrasonic and microwave techniques in the extraction of curcuminoids. Microwave-assisted extraction had the same efficiency as pulsed ultrasonic-assisted extraction, and both methods were better than continuous ultrasonic extraction of curcuminoids. For the pulsed ultrasonic-assisted extraction, the optimal conditions were 60% amplitude (AMP), 83% ethanol (v/v), 3/1 (s/s) pulsed duration/interval time and 10min irradiation time. For the microwave-assisted extraction, the optimal conditions were 82% ethanol, 10% power level and 7min of extraction time. Both methods used a 1:200 mass to solvent ratio. PMID:25038645

Li, Ming; Ngadi, Michael O; Ma, Ying

2014-12-15

92

Computer Simulation of Global Profiles of Carbon Dioxide Using a Pulsed, 2-Micron, Coherent-Detection, Column-Content DIAL System  

NASA Technical Reports Server (NTRS)

We present preliminary results of computer simulations of the error in measuring carbon dioxide mixing ratio profiles from earth orbit. The simulated sensor is a pulsed, 2-micron, coherent-detection lidar alternately operating on at least two wavelengths. The simulated geometry is a nadir viewing lidar measuring the column content signal. Atmospheric absorption is modeled using FASCODE3P software with the HITRAN 2004 absorption line data base. Lidar shot accumulation is employed up to the horizontal resolution limit. Horizontal resolutions of 50, 100, and 200 km are shown. Assuming a 400 km spacecraft orbit, the horizontal resolutions correspond to measurement times of about 7, 14, and 28 s. We simulate laser pulse-pair repetition frequencies from 1 Hz to 100 kHz. The range of shot accumulation is 7 to 2.8 million pulse-pairs. The resultant error is shown as a function of horizontal resolution, laser pulse-pair repetition frequency, and laser pulse energy. The effect of different on and off pulse energies is explored. The results are compared to simulation results of others and to demonstrated 2-micron operating points at NASA Langley.

Kavaya, Michael J.; Singh, Upendra N.; Koch, Grady J.; Yu, Jirong; Frehlich, Rod G.

2009-01-01

93

Determination of Wastewater Compounds in Sediment and Soil by Pressurized Solvent Extraction, Solid-Phase Extraction, and Capillary-Column Gas Chromatography/Mass Spectrometry  

USGS Publications Warehouse

A method for the determination of 61 compounds in environmental sediment and soil samples is described. The method was developed in response to increasing concern over the effects of endocrine-disrupting chemicals in wastewater and wastewater-impacted sediment on aquatic organisms. This method also may be used to evaluate the effects of combined sanitary and storm-sewer overflow on the water and sediment quality of urban streams. Method development focused on the determination of compounds that were chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Sediment and soil samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from interfering matrix components by high-pressure water/isopropyl alcohol extraction. The compounds were isolated using disposable solid-phase extraction (SPE) cartridges containing chemically modified polystyrene-divinylbenzene resin. The cartridges were dried with nitrogen gas, and then sorbed compounds were eluted with methylene chloride (80 percent)-diethyl ether (20 percent) through Florisil/sodium sulfate SPE cartridge, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-sand samples fortified at 4 to 72 micrograms averaged 76 percent ?13 percent relative standard deviation for all method compounds. Initial method reporting levels for single-component compounds ranged from 50 to 500 micrograms per kilogram. The concentrations of 20 out of 61 compounds initially will be reported as estimated with the 'E' remark code for one of three reasons: (1) unacceptably low-biased recovery (less than 60 percent) or highly variable method performance (greater than 25 percent relative standard deviation), (2) reference standards prepared from technical mixtures, or (3) potential blank contamination. Samples were preserved by freezing to -20 degrees Celsius. The U.S. Geological Survey National Water Quality Laboratory has established a 1-year sample-holding time limit (prior to sample extraction) from the date of sample collection (if the sample is kept at -20?C) until a statistically accepted method can be used to determine the effectiveness of the sample-freezing procedure.

Burkhardt, Mark R.; Zaugg, Steven D.; Smith, Steven G.; ReVello, Rhiannon C.

2006-01-01

94

Microwave assisted solvent extraction and coupled-column reversed-phase liquid chromatography with UV detection use of an analytical restricted-access-medium column for the efficient multi-residue analysis of acidic pesticides in soils.  

PubMed

A screening method has been developed for the determination of acidic pesticides in various types of soils. Methodology is based on the use of microwave assisted solvent extraction (MASE) for fast and efficient extraction of the analytes from the soils and coupled-column reversed-phase liquid chromatography (LC-LC) with UV detection at 228 nm for the instrumental analysis of uncleaned extracts. Four types of soils, including sand, clay and peat, with a range in organic matter content of 0.3-13% and ten acidic pesticides of different chemical families (bentazone, bromoxynil, metsulfuron-methyl, 2,4-D, MCPA, MCPP, 2,4-DP, 2,4,5-T, 2,4-DB and MCPB) were selected as matrices and analytes, respectively. The method developed included the selection of suitable MASE and LC-LC conditions. The latter consisted of the selection of a 5-microm GFF-II internal surface reversed-phase (ISRP, Pinkerton) analytical column (50 x 4.6 mm, I.D.) as the first column in the RAM-C18 configuration in combination with an optimised linear gradient elution including on-line cleanup of sample extracts and reconditioning of the columns. The method was validated with the analysis of freshly spiked samples and samples with aged residues (120 days). The four types of soils were spiked with the ten acidic pesticides at levels between 20 and 200 microg/kg. Weighted regression of the recovery data showed for most analyte-matrix combinations, including freshly spiked samples and aged residues, that the method provides overall recoveries between 60 and 90% with relative standard deviations of the intra-laboratory reproducibility's between 5 and 25%; LODs were obtained between 5 and 50 microg/kg. Evaluation of the data set with principal component analysis revealed that the parameters (i) increase of organic matter content of the soil samples and (ii) aged residues negatively effect the recovery of the analytes. PMID:11771842

Hogendoom, E A; Huls, R; Dijkman, E; Hoogerbrugge, R

2001-12-14

95

Multiresidue herbicide analysis in soil samples by means of extraction in small columns and gas chromatography with nitrogen–phosphorus and mass spectrometric detection  

Microsoft Academic Search

A rapid multiresidue method has been developed for the analysis of 21 nitrogen containing herbicides in soil. The compounds included widely used herbicides belonging to triazines, thiocarbamates, uracils, nitroanilines, chloroacetamides and oxadiazon, a non-classified heterocycle. The method is based in the extraction by sonication of soil samples placed in small columns using a low volume of ethyl acetate. Residues were

C Sánchez-Brunete; R. A Pérez; E Miguel; J. L Tadeo

1998-01-01

96

Extraction of zirconium and hafnium from nitric acid solutions by solid extractant based on tributyl phosphate  

SciTech Connect

A study has been made of extraction equilibrium and kinetics and the influence of temperature and aqueous phase acidity on the extraction of zirconium and hafnium from nitric acid solutions by a solid extractant based on tributyl phosphate. Results are presented from pilot-plant experiments on Zr and Hf extraction from acidic pulps with high silicon contents, using pulsed columns.

Korovin, V.Yu.; Yagodin, G.A.; Savel`eva, V.I. [Dnieper Scientific Center, Dneprodzerzhinsk (Ukraine)

1994-10-20

97

Next-generation pulse oximetry. Focusing on Masimo's signal extraction technology.  

PubMed

Pulse oximeters are used to determine trends in patients' blood oxygen saturation and to warn of dangerous saturation levels. But conventional pulse oximetry has some inherent limitations. For example, it has difficulty monitoring patients who are moving or who have poor perfusion; it is also subject to interference from certain visible and infrared light sources. Over the past several years, a number of companies have developed advanced signal-processing techniques that allow pulse oximeters to overcome many of these limitations. We refer to such new technologies as next-generation pulse oximetry. In this Evaluation, we focus on the first next-generation technology to have reached the market: Masimo Corporation's Signal Extraction Technology (SET). We designed our study of Masimo SET to address the main question that needs to be asked of any next-generation technology: How well does it compare to conventional pulse oximetry? Specifically, how well does it perform when a patient is moving or being moved, when a patient is poorly perfused, or when certain types of light strike the sensor while it is attached to or detached from the patient? We also examined one type of sensor used with this product, comparing it to conventional tape-on sensors for comfort and durability. Several other next-generation pulse-oximeter products have become available since we began this study. We are currently evaluating these products and will publish our findings in the near future. A list of the products, including a brief description of each, is included in this article. Pulse oximeters are used to determine trends in patients' blood oxygen saturation and to warn against dangerous saturation levels. These monitors are often vital in helping to ensure patient safety, especially for critically ill patients, pediatric patients, and neonates. But conventional pulse oximetry has some inherent limitations--most significantly, it has difficulty monitoring patients who are moving or who have poor perfusion. Although gradual improvements have been made to the technology, only recently has it advanced to the point where it has really begun to overcome these limitations. A number of manufacturers have developed advanced signal-processing algorithms that allow pulse oximeters to "read through" motion and conditions of poor perfusion. The first of these "next-generation" pulse-oximeter technologies that reached the market was Masimo Corporation's Signal Extraction Technology (SET). We tested that product in this Evaluation. In this Overview, we'll tell you about conventional pulse oximetry and its shortfalls, next-generation technology and how it's designed to improve on the old methods, and how we approached our Evaluation of Masimo SET. PMID:11094776

2000-10-01

98

Characterization of a high-pressure laser ion source with dc and pulsed extraction  

NASA Astrophysics Data System (ADS)

The Dublin City University (DCU) laser ion source (LIS) is a compact, high-throughput system which utilizes a very short field-free region (L = 4.8 cm) so ion extraction at the anode occurs at 'high pressure'. Detailed studies of the system performance are reported here for a range of laser power densities (Ip ~ (0.35-2.4) × 1011 W cm-2) and extraction voltages (dc 5-17 kV, pulsed 15-40 kV). Extracted ion beam currents were measured with the aid of a Faraday cup and ranged from ~3.2 mA (Cu2+) to 0.1 mA (Cu6+). Pronounced turning points in the current profiles were observed for both dc and pulsed extraction, related to so-called 'plasma bulge' at the anode which in turn has its origins in the high plasma density at extraction. The kinetic energy of Cu2+ ions was quantified for a range of extraction bias values and used to determine the extraction efficiency. A planar probe, employed to measure the radial profile of the ion beam, yielded minimum beam diameters of ~6-8 mm for Cu+ and Cu2+. These data were used to determine the collected current density J, which peaked at 1.92 mA cm-2. Using a gated intensified charge coupled device camera, the internal structure of the extracted ion bunches was imaged and ion number densities estimated. The dependence of other key beam parameters on focusing optics, laser energy and extraction voltage was also investigated.

Yeates, P.; Costello, J. T.; Kennedy, E. T.

2010-12-01

99

Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column.  

PubMed

A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4 mL min(-1), the catechins and caffeine were isocratically separated in about 7 min. The limits of detection and quantification were in the range of 0.11-0.29 and 0.33-0.87 mg L(-1), respectively. Satisfactory recoveries were obtained (94.2-105.2 ± 1.8%) for all samples when spiked at three concentrations (5, 40 and 70 mg L(-1)). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas. PMID:24206716

Rahim, A A; Nofrizal, S; Saad, Bahruddin

2014-03-15

100

Phytochemical analysis of ethanolic extract of Dichrostachys Cinerea W and Arn leaves by a thin layer chromatography, high performance thin layer chromatography and column chromatography  

PubMed Central

Background: The leaves of Dichrostachys cinerea are used as laxative, diuretic, painkiller. It is also used in the treatment of gonorrhoea, boils, oedema, gout, veneral diseases and nasopharyngeal affections, etc. Materials and Methods: The Phytochemical investigation of ethanolic extract of D. cinerea leaves were performed by standard chemical tests, thin layer chromatography (TLC) by using various solvent systems, and by high performance liquid chromatography (HPTLC). Two compounds were isolated by column chromatography and one of the compounds was identified by various spectral studies. Result: Preliminary phytochemical screening of ethanolic extract of D. cinerea leaves showed the presence of Carbohydrates, proteins, Glycosides, Saponins, Tannins, Aminoacids and Terpenoids. The TLC and HPTLC fingerprint of ethanolic extract were studied and various fractions were isolated by column chromatography and one of the fraction contain ?-amyrin glucoside which was confirmed by Infra Red[IR] Spectroscopy, 1H-Nuclear Magnetic Resonance (NMR), C-13 NMR and Mass spectroscopic (MS) studies.

Vijayalakshmi, M.; Periyanayagam, K.; Kavitha, K.; Akilandeshwari, K.

2013-01-01

101

Cleanup and Analysis of Sugar Phosphates in Biological Extracts by Using SolidPhase Extraction and AnionExchange Chromatography with Pulsed Amperometric Detection  

Microsoft Academic Search

A cleanup method based on anion-exchange solid-phase extraction (SPE) was developed to render biological extracts suitable for the analysis of hexose phosphates with a modified anion-exchange chromatography method and pulsed amperometric detection. The method was applied to cell extracts ofSaccharomyces cerevisiaeobtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the

Hans Peter Smits; Arieh Cohen; Torbjörn Buttler; Jens Nielsen; Lisbeth Olsson

1998-01-01

102

Comparison of analytical and semi-preparative columns for high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance.  

PubMed

The application of analytical and semi-preparative columns in reversed-phase liquid chromatography-solid-phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) was compared. The work was aiming at separating a higher sample amount in a single run and in this way to reduce the necessary NMR measurement time of separated compounds. Several parameters for compound separation and trapping procedures were optimised: flow rate of HPLC and make-up water pumps, choice of stationary phase cartridges and drying time. The separation and loadability of nine model compounds on analytical and semi-preparative columns was determined, as well as the focussing capacity of SH-type SPE cartridges. It was found that a semi-preparative column--or multiple peak trapping on analytical columns--gave better results than a standard 4.6mm analytical column for non-polar compounds (e.g. flavonoid aglycones, sesquiterpene lactones, non-polar terpenes, logP>2), but for polar compounds (logP<-2) did not offer any advantage over an analytical column, or was even disadvantageous. For intermediately polar compounds (-2

Miliauskas, Giedrius; van Beek, Teris A; de Waard, Pieter; Venskutonis, Rimantas P; Sudhölter, Ernst J R

2006-04-21

103

Determination of Sudan dyes in chili pepper powder by online solid-phase extraction with a butyl methacrylate monolithic column coupled to liquid chromatography with tandem mass spectrometry.  

PubMed

A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was fabricated and used as a novel sorbent for online solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry for the simultaneous determination of Sudan I-IV in chili pepper powder. The prepared columns were characterized by scanning electron microscopy, nitrogen adsorption-desorption, and pressure drop measurements. Online solid-phase extraction was performed on the synthesized monolithic column using 10 mM ammonium acetate solution as the loading solution with the aid of an online cleanup chromatography system. The desorption of Sudan I-IV was achieved with acetonitrile as the eluting solution at the flow rate of 0.5 mL/min. The extracted analytes were subsequently eluted into a C18 analytical column for chromatographic separation using a mixture of 10% acetonitrile/90% formic acid (0.5%) solution as the mobile phase. Under the optimized conditions, the developed method had linear range of 1.0-50 ?g/kg, a detection limit of 0.3 ?g/kg, and a quantification limit of 1.0 ?g/kg for each analyte. The intraday and interday recoveries of Sudan I-IV in chili pepper powder samples ranged from 94.8 to 100.9% and 94.9 to 99.4%, respectively. The intraday and interday precision were between 3.37-7.01% and 5.01-7.68%, respectively. PMID:24723310

Liu, Yao; Wang, Man-Man; Ai, Lian-Feng; Zhang, Chang-Kun; Li, Xin; Wang, Xue-Sheng

2014-07-01

104

Adaptive pulsed laser line extraction for terrain reconstruction using a dynamic vision sensor  

PubMed Central

Mobile robots need to know the terrain in which they are moving for path planning and obstacle avoidance. This paper proposes the combination of a bio-inspired, redundancy-suppressing dynamic vision sensor (DVS) with a pulsed line laser to allow fast terrain reconstruction. A stable laser stripe extraction is achieved by exploiting the sensor's ability to capture the temporal dynamics in a scene. An adaptive temporal filter for the sensor output allows a reliable reconstruction of 3D terrain surfaces. Laser stripe extractions up to pulsing frequencies of 500 Hz were achieved using a line laser of 3 mW at a distance of 45 cm using an event-based algorithm that exploits the sparseness of the sensor output. As a proof of concept, unstructured rapid prototype terrain samples have been successfully reconstructed with an accuracy of 2 mm.

Brandli, Christian; Mantel, Thomas A.; Hutter, Marco; Hopflinger, Markus A.; Berner, Raphael; Siegwart, Roland; Delbruck, Tobi

2014-01-01

105

Atmospheric Backscatter Profiles at 1572nm from Pulsed Lidar Measurments of CO2 Column Absorption from the 2011 ASCENDS Flight Campaign  

NASA Astrophysics Data System (ADS)

We present height-resolved backscatter profiles from the NASA Goddard Space Flight Center's CO2 sounder lidar, rich in detail, which shows clear evidence of multiple backscatter layers, clouds, and aerosols allowing for the identification of the Planetary Boundary Layer (PBL). This data is recorded as a consequence of our pulsed lidar measurements of the CO2 column absorption. The CO2 Sounder is a pulsed lidar for active remote measurements of CO2 abundance from an airborne platform and is one candidate for the lidar on the NASA ASCENDS mission. The lidar uses a scanning, pulsed laser and fiber amplifier in a Master Oscillator Power Amplifier (MOPA) configuration to measure CO2 absorption at 1572.335 nm, lineshape, range to scattering surface and backscatter profiles. The laser is scanned across the absorption feature measuring at 30 discrete wavelengths/scan and ~300 scans/sec. The time-resolved return signal, with a temporal resolution of 8ns, is detected by a photon-counting PMT fiber coupled to a modified commercial, 2m focal length f10 Schmidt-Cassegrain telescope. The column density for CO2 is estimated from the differential optical depth (DOD) of the scanned absorption line using an integrated-path differential absorption (IPDA) technique and the optical path from the time of flight. A backscatter profile of the measured column is recorded for every pulse of every scan and integrated for 1 second. The backscatter profiles we will show are determined from the receivers photon counting record using a cross-correaltion technique (sliding inner product) with a vertical resolution of better than 300m, set by the 1?s pulse width from the MOPA. The range to the surface can be determined to a few meters. Major benefits of a pulsed technique using time-resolved detection to measure lineshape, is the unambiguous detection of the ground return, intervening clouds, aerosols and information on the vertical distribution of CO2. This technique can uniquely identify the ground-return, removing scatter due to intervening aerosols and clouds, notably sub-visible cirrus, which improves the accuracy of the retrieval. Further analyses of the CO2 column incorporating the backscatter profiles allows for the identification of the PBL. Identification of the height above ground of the PBL in which the CO2 is greatly varying, both spatially and temporally, improves the quality of the retrieval from the knowledge of both the lineshape and depth of the PBL. We will present backscatter data from the 2011 ASCENDS campaign from predominantly the central and western USA. The data, rich in detail, shows clear evidence of multiple backscatter layers, clouds, the PBL, surface aerosols and smoke plumes from forest fires to clear air column over the Pacific Ocean.

Allan, G. R.; Riris, H.; Hasselbrack, W.; Sun, X.; Ramanathan, A.; Mao, J.; Abshire, J. B.

2012-12-01

106

Effects of pulsed UV-light on peanut allergens in extracts and liquid peanut butter.  

PubMed

Pulsed ultraviolet (PUV) light, a nonthermal technology, was used to treat both the peanut extracts and liquid peanut butter. The objective was to determine if such treatment would lead to a reduction in the allergenic properties of the peanut extract and butter. Peanut samples were PUV treated using a Xenon RS-3000C under the following conditions: 3 pulses/s, 14.6 cm from the central axis of the lamp, 4 min (extract) or 3 min (liquid peanut butter). After the treatment, the peanut samples were centrifuged and the supernatants analyzed by SDS-PAGE and competitive inhibition enzyme-linked immunosorbent assay (ciELISA). For comparison, boiling treatments were also performed. SDS-PAGE showed that while boiling treatment had little effect on the peanut allergens, PUV-light-treated samples displayed a reduced solubility or level of peanut allergens (63 kDa). Solubility of another allergen (18 to 20 kDa) was unaffected. Insoluble aggregates formed were responsible for the reduced level of allergens in PUV-light-treated samples. ciELISA showed that untreated samples exhibited an IgE binding 7-fold higher than the PUV-treated samples. It was concluded that PUV light was effective in reducing IgE binding of peanut extracts and liquid peanut butter. The current study provides an approach to the development of a possibly less allergenic peanut product. However, the reduction in actual allergenicity needs to be confirmed by clinical studies. PMID:18576985

Chung, S-Y; Yang, W; Krishnamurthy, K

2008-06-01

107

Use of selective extraction chromatographic columns as an alternative to solvent extraction for the separation of uranium followed by the use of Arsenazo III as a colorimetric reagent for uranium determination.  

National Technical Information Service (NTIS)

The use of U/TEVA(reg sign) Spec columns as an alternative to solvent extraction for separation of uranium prior to its determination by various techniques (calorimetric, phosphorescence, and mass spectroscopy) was investigated. U/TEVA(reg sign) Spec colu...

C. J. Miller J. R. Del Mastro

1994-01-01

108

Performance of programmed temperature vaporizer, pulsed splitless and on-column injection techniques in analysis of pesticide residues in plant matrices.  

PubMed

A programmed temperature vaporizer (PTV) injection technique has been recently implemented in our laboratory. In present paper its performance is compared with other GC injection techniques commonly used in trace analysis of organic contaminants. Twenty-six pesticides representing different chemical classes were selected for the study. This group comprised compounds typically subjected to discrimination in the injection port of the gas chromatograph, e.g., polar organophosphorus pesticides and thermolabile carbamates. In the first set of experiments standards in pure solvent were injected into GC systems employing different types of injection, i.e., (i) on-column, (ii) pulsed splitless, (iii) PTV solvent split, (iv) PTV splitless, and the responses of analytes were compared. Discrimination of troublesome compounds was significantly decreased with the application of PTV solvent split injection. In the second set of experiments repetitive injections of purified wheat samples were performed, with aims to evaluate the long-term stability of responses, as well as matrix effects in different stages of system contamination for each injection technique. The tolerance of the GC system to co-injected matrix components was increased in the order: on-column splitlesspulsed splitless injection. With the latter technique after 66 injections of wheat samples relative responses (apparent recovery) reached as much as 450% for some compounds, while with the application of PTV matrix effects did not exceed 200% under the same conditions. PMID:11765087

Zrostlíková, J; Hajslová, J; Godula, M; Mastovská, K

2001-12-01

109

Pulsed counter-current ultrasound-assisted extraction and characterization of polysaccharides from Boletus edulis.  

PubMed

Four methods for extracting polysaccharides from Boletus edulis, namely, hot-water extraction, ultrasonic clearer extraction, static probe ultrasonic extraction, and pulsed counter-current probe ultrasonic extraction (CCPUE), were studied. Results showed that CCPUE has the highest extraction efficiency among the methods studied. Under optimal CCPUE conditions, a B. edulis polysaccharide (BEP) yield of 8.21% was obtained. Three purified fractions, BEP-I, BEP-II, and BEP-III, were obtained through sequential purification by DEAE-52 and Sephadex G-75 chromatography. The average molecular weights of BEP-I, BEP-II, and BEP-III were 10,278, 23,761, and 42,736 Da, respectively. The polysaccharides were mainly composed of xylose, mannose, galactose, and glucose; of these, mannose contents were the highest. The antioxidant activities of the BEPs were further investigated by measurement of their ability to scavenge DPPH and hydroxyl radicals as well as their reducing power. The results indicated that the BEPs have good antioxidant activity. PMID:24299786

You, Qinghong; Yin, Xiulian; Ji, Chaowen

2014-01-30

110

Determination of benzodiazepines in human hair by on-line high-performance liquid chromatography using a restricted access extraction column  

Microsoft Academic Search

A method is described for the identification of five frequently prescribed benzodiazepines (BZD) (clonazepam, diazepam, flunitrazepam, midazolam and oxazepam) in human hair samples by reversed phase HPLC, following on-line simple enrichment and clean-up on a restricted access extraction column.50mg of powdered hair were incubated (2h at 45°C) after sonication (1h) in 1ml of the following solution (methanol:ammonia, 97.5\\/2.5, v\\/v). The

Anissa El Mahjoub; Christian Staub

2001-01-01

111

Determination of copper, lead and iron in water and food samples after column solid phase extraction using 1-phenylthiosemicarbazide on Dowex Optipore L-493 resin  

Microsoft Academic Search

A novel solid phase extraction procedure for determination of copper, lead and iron in natural water and food samples has been established in the presented work. 1-Phenylthiosemicarbazide (1-PTSC) as ligand and Dowex Optipore L-493 resin as adsorbent were used in a mini chromatographic column. Various analytical conditions for the quantitative recoveries of analyte ions including pH, amounts of adsorbent, eluent,

Ozden Y?ld?z; Demirhan Citak; Mustafa Tuzen; Mustafa Soylak

2011-01-01

112

Simultaneous multi-mycotoxin determination in nutmeg by ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection.  

PubMed

A simple and sensitive analytical method based on ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with high performance liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection (USLE-IAC-HPLC-PCD-FLD) has been developed for simultaneous multi-mycotoxin determination of aflatoxins B1, B2, G1, G2 (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) in 13 edible and medicinal nutmeg samples marketed in China. AFs and OTA were extracted from nutmeg samples by ultrasonication using a methanol?:?water (80?:?20, v/v) solution, followed by an IAC clean-up step. Different USL extraction conditions, pre-processing ways for nutmeg sample and clean-up columns for mycotoxins, as well as HPLC-PCD-FLD parameters (mobile phase, column temperature, elution procedure, excitation and emission wavelengths) were optimized. This method, which was appraised for analyzing nutmeg samples, showed satisfactory results with reference to limits of detection (LODs) (from 0.02 to 0.25 ?g kg(-1)), limits of quantification (LOQs) (from 0.06 to 0.8 ?g kg(-1)), linear ranges (up to 30 ng mL(-1) for AFB1, AFG1 and OTA and 9 ng mL(-1) for AFB2 and AFG2), intra- and inter-day variability (all <2%) and average recoveries (from 79.6 to 90.8% for AFs and from 93.6 to 97.3% for OTA, respectively). The results of the application of developed method in nutmeg samples have elucidated that four samples were detected with contamination of AFs and one with OTA. AFB1 was the most frequently found mycotoxin in 30.8% of nutmeg samples at contamination levels of 0.73-16.31 ?g kg(-1). At least two different mycotoxins were co-occurred in three samples, and three AFs were simultaneously detected in one sample. PMID:23486692

Kong, Wei-Jun; Liu, Shu-Yu; Qiu, Feng; Xiao, Xiao-He; Yang, Mei-Hua

2013-05-01

113

A Fast-sampling, Planar Array for Measuring the AC Field of Fermilab Pulsed Extraction Magnets  

SciTech Connect

A system employing a planar array of inductive pick-up coils has been developed for measurements of the rapidly changing dipole field in pulsed extraction magnets for the Fermilab MuCool project. The magnets are of C-type and deigned to support a peak field of 0.65 T during 8.33 millisecond half-sine pulse at a 15 Hz repetition rate. The coils of the measurement system are fabricated on a single, 97.5 mm wide, 2-layer circuit board. The array of coils is simultaneously sampled at data rates of up to 100 kHz with 10 kHz bandwidth using 24-bit ADC's. A detailed overview of the system and data analysis is presented, along with a characterization of results and system performance.

DiMarco, E.Joseph; Johnstone, C.; Kiemschies, O.; Kotelnikov, S.K.; Lamm, M.J.; Makulski, A.; Nehring, R.; Orris, D.F.; Russell, A.D.; Tartaglia, Michael Albert; Velev, G.; /Fermilab

2008-06-25

114

Determination of benzodiazepines in human hair by on-line high-performance liquid chromatography using a restricted access extraction column.  

PubMed

A method is described for the identification of five frequently prescribed benzodiazepines (BZD) (clonazepam, diazepam, flunitrazepam, midazolam and oxazepam) in human hair samples by reversed phase HPLC, following on-line simple enrichment and clean-up on a restricted access extraction column. 50mg of powdered hair were incubated (2h at 45 degrees C) after sonication (1h) in 1 ml of the following solution (methanol:ammonia, 97.5/2.5, v/v). The aliquot was centrifuged and the methanolic phase transferred to a conical tube and evaporated under a gentle stream of nitrogen. The residue was reconstituted by adding 100 microl of a mixture of phosphate buffer (20mM, pH=2.2) and acetonitrile (94/6, v/v). A total of 80 microl were injected into the system with the column switching technique. The pre-column or clean-up column was washed with phosphate buffer pH=7.2. The drugs retained on the pre-column were then eluted in the back-flush mode and separated on a C(8) semi micro column, Lichrospher select B, 125 mm x 3 mm. The BZD were determined by a photodiode-array detector at 254 nm, using reference data (retention time and UV spectra) stored in a personal library. The method showed excellent linearity between 0.5 and 20 ng/mg of hair for clonazepam, flunitrazepam and midazolam and between 0.5 and 100 ng/mg of hair for diazepam and oxazepam. Finally, the present method has been applied to a number of forensic cases in our laboratory. PMID:11731192

El Mahjoub, A; Staub, C

2001-11-15

115

Atmospheric Backscatter Profiles at 765nm and 1572nm from Pulsed Lidar Measurements of CO2 and O2 Column Absorption from the 2013 ASCENDS Flight Campaign  

NASA Astrophysics Data System (ADS)

We present height-resolved, range corrected, backscatter profiles from NASA GSFC's two-channel (CO2 & O2) sounder, an Integrated Path Differential Absorption (IPDA) lidar, which measures simultaneously both carbon dioxide & oxygen column absorptions. These backscatter profiles show clear evidence of multiple backscattering layers, clouds & aerosols, which allows for the identification of the Planetary Boundary Layer (PBL). The backscatter measurements enable sampling of the vertical distribution of CO2 in the atmosphere when broken & thin clouds are present & may help identify sources & sinks within the PBL as opposed to natural variations in the vertical distribution of CO2. The CO2 Sounder is an airborne pulsed lidar for active remote measurements of CO2 abundance & is a candidate for NASA's ASCENDS mission (Active Sensing of CO2 Emissions over Nights, Days & Seasons). The O2 channel measures atmospheric pressure in the same air column to calculate the dry mixing ratio of CO2. The lidars use a scanning, pulsed laser & fiber amplifier in a Master Oscillator Power Amplifier configuration to measure lineshape, range to scattering surface & backscatter profiles. The CO2 channel operates at 1572.335 nm. The O2 channel uses similar technology but frequency doubles the output from ~1530nm to the O2 A-band absorption around 765nm. Both lasers are scanned across the absorption feature of interest sampling the line at a fixed number of discrete wavelengths per scan around ~300 scans per second. The time-resolved return signal is detected by photon-counting detectors with a temporal resolution of a few nanoseconds. The CO2 channel uses a PMT while the O2 channel uses Single Photon Counting Modules. The detectors are fiber coupled to a 2m f10 Schmidt-Cassegrain telescope. The column density of the gas of interest is estimated from the differential optical depths of the scanned absorption using the IPDA technique & the optical path from the time of flight. A backscatter profile of the measured column is recorded for every pulse of every scan & integrated along track for 1 second. Major benefits of a time-resolved pulsed technique is the unambiguous detection of the ground return, intervening clouds, aerosols & information on the vertical distribution of CO2. Additionally the difference in backscatter between the two channels gives some information on particle size. We will present backscatter data from the Summer 2011 & Winter 2013 ASCENDS campaign from predominantly the central & western USA. The data, rich in detail, shows clear evidence of multiple backscatter layers, clouds, the PBL, & aerosols. False-color backscatter counts(arb units) at 765nm, recorded east of and over the Rocky Mountains, March 8, 2013. This plot, rich in detail, clearly shows the ground return, aerosols and clouds.

Allan, G. R.; Riris, H.; Hasselbrack, W.; Rodriguez, M.; Ramanathan, A.; Sun, X.; Mao, J.; Abshire, J. B.

2013-12-01

116

Determination of trigonelline, nicotinic acid, and caffeine in Yunnan Arabica coffee by microwave-assisted extraction and HPLC with two columns in series.  

PubMed

A simple, rapid method was developed for simultaneous extraction of trigonelline, nicotinic acid, and caffeine from coffee, and separation by two chromatographic columns in series. The trigonelline, nicotinic acid, and caffeine were extracted with microwave-assisted extraction (MAE). The optimal conditions selected were 3 min, 200 psi, and 120 degrees C. The chromatographic separation was performed with two columns in series, polyaromatic hydrocarbon C18 (250 x 4.6 mm id, 5 microm particle size) and Bondapak NH2 (300 x 3.9 mm id, 5 microm particle size). Isocratic elution was with 0.02 M phosphoric acid-methanol (70 + 30, v/v) mobile phase at a flow rate of 0.8 mL/min. Good recoveries and RSD values were found for all analytes in the matrix. The LOD of the three compounds was 0.02 mg/L, and the LOQ was 0.005% in the matrix. The concentrations of trigonelline, nicotinic acid, and caffeine in instant coffee, roasted coffee, and raw coffee (Yunnan Arabica coffee) were assessed by MAE and hot water extraction; the correlation coefficients between concentrations of the three compounds obtained were close to 1. PMID:22970583

Liu, Hongcheng; Shao, Jinliang; Li, Qiwan; Li, Yangang; Yan, Hong Mei; He, Lizhong

2012-01-01

117

Development and Validation of an HPLC Method for Determination of Amikacin in Water Samples by Solid Phase Extraction and Pre-column Derivatization.  

PubMed

This work presents a rapid and sensitive high performance liquid chromatography method for the determination of amikacin in water samples with solid phase extraction and pre-column derivatization. Amikacin residue was extracted from water samples with solid phase extraction cartridge. Then the extraction solution was derivatized with 4-chloro-3,5-dinitrobenzotrifluoride in the presence of triethylamine at 70°C in 20 min. The amikacin derivative was separated on a C18 column and detected by application of UV detection at 238 nm. The limit of detection is 0.2 ?g/L with a signal-to-noise ratio of 3 and linearity is established over the concentration range from 0 to 500.0 ?g/L. Recoveries of the amikacin in three types of water samples are from 87.5 % to 99.6 % and RSDs are 2.1 %-4.5 %. This method can be used for the quantification of amikacin residues in water samples. PMID:24663966

Li, Deguang; He, Shun; Deng, Yufang; Ding, Guanglong; Ni, Hanwen; Cao, Yongsong

2014-07-01

118

Molecularly imprinted solid phase extraction-pulsed elution-mass spectrometry for determination of cephalexin and alpha-aminocephalosporin antibiotics in human serum.  

PubMed

A highly selective molecularly imprinted solid phase extraction (MISPE)-pulsed elution (PE) method coupled with electrospray mass spectrometry (MS) was developed for the rapid screening and determination of cephalexin in alpha-aminocephalosporin antibiotics. This method involved the solid phase extraction of cephalexin using a molecularly imprinted polymer micro-column, and pulsed elution with 1% trifluoroacetic acid in methanol, which contains sulindac as an internal standard for enhanced precision in MS detection. An LC/MS spectrometer was operated in the positive electrospray mode, and the selected-ion-recording (SIR) function was employed to detect the molecular ions of cephalexin, cefradine, cefadroxil and sulindac at m/z 348, 350, 363 and 357. Linearity was achieved in the cephalexin concentration range from 0.3 to 25microg/ml (or 5-500ng) (R(2) = 0.998). The detection limit was estimated at 0.04microg/ml (or 0.8ng) of cephalexin. Advantages of the newly developed MISPE-PE-MS, over the previously reported MISPE-DPE-FPE-UV, were evidenced in terms of detection limit, analysis time, solvent consumption, and simplicity of method development. PMID:15522521

Wu, Stanley G; Lai, Edward P C; Mayer, Paul M

2004-11-15

119

Extraction of He and NE from Individual Lunar Ilmenite Grains by Pulse Heating  

NASA Astrophysics Data System (ADS)

The pulse-heating technique employed for extracting helium and neon from individual interplanetary dust particles [1] has been extended to a similar study of individual lunar grains. A succession of 5-s constant power pulses is applied to the oven holding the particle. The power is increased in 0.25-W increments until all the gas is removed. The peak temperature reached during a pulse lasts about 2 s and increases by roughly 75 degrees C for each 0.25-W increment in power. In the present investigation six individual ilmenite grains of lunar soil 71501 and of breccia 79035 were studied. It was felt that this method of extracting the gas might help in distinguishing between surface embedded solar wind (SW) particles and more deeply embedded constituents such as solar energetic particles (SEP) [2], or gas of trapped or primordial origin. Although only six particles of each type have been studied to date, interesting results are beginning to emerge. For example, for both types of particles, for the initial low power pulses where the maximum pulse temperature does not exceed 500 degrees C, the ^3He/^4He ratio falls near 4 x 10^-4, as expected, if the helium is primarily unfractionated solar wind implanted near the surface. As the pulse temperature is increased to around 1000 degrees C and the solar wind gas presumably has been removed, the ^3He/^4He ratio falls to around 2.5 x 10^-4, in rough agreement with the layer etching results [2]. Likewise, the ^20Ne/^22Ne ratio falls from around 14 to a value near 12, as in the etching experiments [2]. In the case of ^4He/^20Ne ratios there appears to be a real difference between the particles from the two ilmenites. For the 79035 grains, the ratio falls from around 600 for the surface gas to around 150 for the later high-temperature extractions. On the other hand, for the 71501 grains, the ratio starts somewhat lower, near 400, and drops below 100 as the pulse temperature is raised. A qualitatively similar difference was observed in the total gas released by laser beam extractions performed on single grains from the same lunar ilmenite samples [3]. While there is considerable scatter in the data, the overall results are gratifying, and should become more definitive as more particles are investigated. The initial releases, almost certainly from the surfaces of the particles, come closer to the solar wind values [4] than generally reported for lunar grains. It will be interesting to see whether or not the differences observed are real and have a bearing on the general problem of the variation of the solar wind with time [5]. Acknowledgment: We are indebted to R. Wieler for the ilmenite grains used in the investigation. References: [1] Nier A. O. and Schlutter D. J. (1993) LPS XXIV, 1075-1076.[2] Wieler R. et al. (1986) GCA, 50, 1997-2017. [3] Olinger C. T. et al. (1990) Meteoritics, 25, 394. [4] Geiss J. et al. (1972) Apollo 16 Prelim. Sci. Rept., 14-1 to 14-10, NASA SP 315. [5] Becker R. H. and Pepin R. O. (1989) GCA, 53, 1135-1146.

Nier, A. O.; Schlutter, D. J.

1993-07-01

120

Analysis of low levels of oxygen, carbon monoxide, and carbon dioxide in polyolefin feed streams using a pulsed discharge detector and two PLOT columns.  

PubMed

A gas chromatography (GC) method is developed for rapid analysis of polyolefin feed streams for the catalyst poisons CO, CO(2), and O(2). The method uses an HP MoleSieve column in parallel with a CP-PoraPLOT Q column and a pulsed discharge detector (PDD). Detection limits for each of the potential poisons are between 50 and 250 ppb. For a 10-ppm standard, the precision of the method was +/- 4.2% for oxygen, +/- 7.8% for carbon dioxide, and +/- 2.0% for carbon monoxide. In addition to the polyolefin feed stream, nitrogen and hydrogen feed streams are also analyzed. In each case, sampling is observed to be a critical issue, with air contamination of the sample cylinder often the limiting step in determining the true level of oxygen. It is also noted that large amounts of argon are present in the standards when nitrogen is used as a balance gas. Because the trace oxygen peak partly coelutes with the larger argon peak, it is suggested that helium be used as the balance gas for all standards. This general experimental arrangement should be effective when applied to feed streams for other polymers as well. PMID:14629793

Wurm, David B; Sun, Kefu; Winniford, William L

2003-01-01

121

A molecularly imprinted organic-inorganic hybrid monolithic column for the selective extraction and HPLC determination of isoprocarb residues in rice.  

PubMed

An IPC-imprinted (IPC is isoprocarb) poly(methacrylic acid)/SiO2 hybrid monolithic column was prepared and applied for the recognition of the template. The hybrid monolithic column was synthesized in a micropipette tip using methyltrimethoxysilane as the inorganic precursor, 3-(methacryloxy)propyltrimethoxysilane as the coupling agent, and ethylene glycol dimethacrylate as the cross-linker. The synthesis conditions, including the porogenic solvent, coupling agent, volume ratio of the inorganic alcoholysate and organic part, were optimized. The prepared monolithic column was characterized by SEM and FTIR spectroscopy. A simple, rapid, and sensitive method for the determination of IPC in rice using the imprinted monolithic column microextraction combined with HPLC was developed. Several parameters affecting the sample pretreatment were investigated, including the eluent, washing solution, and loading sample volume. The linearity of the calibration curve was observed in the range of 9.0-1000 ?g/kg for IPC in rice with the correlation coefficient (r2) of 0.9983. The LOD was 3.0 ?g/kg (S/N = 3). The assay gave recovery values ranging from 91 to 107%. The proposed method has been successfully applied for the selective extraction and sensitive determination of IPC in rice and a satisfactory result was obtained. PMID:24376214

Yang, Ting; Ma, Chao; Chen, Huaixia; Zhang, Yajie; Dang, Xueping; Huang, Jianlin

2014-03-01

122

Rapid trace level determination of sulfonamide residues in honey with online extraction using short C-18 column by high-performance liquid chromatography with fluorescence detection.  

PubMed

A sensitive and inexpensive quantification method with online extraction using a short C-18 column for sulfonamide residues in honey by high performance liquid chromatography with fluorescence detector was developed and validated. In sample preparation, acid hydrolysis was used to break the N-glycoside bond between the honey sugar and sulfonamide drugs and derivatization of sulfonamide residues with fluorescamine was conducted at pH 3.5 using a citrate buffer (0.5M) in the honey matrix. The chromatography was carried out on Zorbax Extended C-18 (250mm×4.6mm; 5?m) column, using a mixture of acetonitrile and an acetate buffer (pH 4.50, 20mM) as a mobile phase. A Zorbax Extended C-18 (12mm×4.6mm; 5?m) column was used for online extraction of fifteen sulfonamide residues from honey sample with the help of a two position valve. The limit of quantification of sulfonamide residues in honey was less than 3ngg(-1), and the percentage recovery of study compounds in spiked honey sample was from 80% for sulfacetamide to 100% of sulfachloropyridazine. The developed method has excellent linearity for all studied sulfonamides with a correlation coefficient 0.993. PMID:24055224

Sajid, Muhammad; Na, Na; Safdar, Muhammad; Lu, Xin; Ma, Lin; He, Lan; Ouyang, Jin

2013-11-01

123

Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection.  

PubMed

A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d(5) was used as an internal standard. The linear ranges were 0.01-5.0 microg mL(-1) for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 microg mL(-1) for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation > or = 0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 microg mL(-1) of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio > or = 3) in urine was 5 ng mL(-1) for MA and MDMA and 10 ng mL(-1) for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation. PMID:20113714

Nakamoto, Akihiro; Nishida, Manami; Saito, Takeshi; Kishiyama, Izumi; Miyazaki, Shota; Murakami, Katsunori; Nagao, Masataka; Namura, Akira

2010-02-19

124

Simultaneous determination of dibucaine and naphazoline in human serum by monolithic silica spin column extraction and liquid chromatography-mass spectrometry.  

PubMed

A simple, sensitive, and specific liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of dibucaine and naphazoline from serum was developed and validated. The extraction procedure was performed using a monolithic silica spin column. Chromatographic separation of dibucaine and naphazoline was achieved on a C(18) reverse phase column with a mobile phase gradient (mobile phase A: 10 mM ammonium formate and mobile phase B: acetonitrile) at a flow rate of 0.2 mL/min. LC-MS was operated under the selective ion monitoring mode using the electrospray ionization technique in the positive mode. The retention times for naphazoline, dibucaine, and the internal standard (IS) were 6.7, 7.8, and 8.0 min, respectively. A linear graph was obtained for dibucaine and naphazoline with correlation coefficients >0.998 for all analytes by this method. The limit of quantification of dibucaine and naphazoline was 10 and 25 ng/mL, respectively. The mean recoveries were greater than 70%. Both compounds were stable under conditions of short-term storage, long-term storage as well as after freeze-thaw cycles. Monolithic spin column extraction and LC-MS analysis enabled the separation of dibucaine and naphazoline within 20 min. PMID:18657485

Saito, Takeshi; Morita, Seiji; Kishiyama, Izumi; Miyazaki, Shota; Nakamoto, Akihiro; Nishida, Manami; Namera, Akira; Nagao, Masataka; Inokuchi, Sadaki

2008-09-01

125

Cold column trapping-cloud point extraction coupled to high performance liquid chromatography for preconcentration and determination of curcumin in human urine.  

PubMed

A cold column trapping-cloud point extraction (CCT-CPE) method coupled to high performance liquid chromatography (HPLC) was developed for preconcentration and determination of curcumin in human urine. A nonionic surfactant, Triton X-100, was used as the extraction medium. In the proposed method, a low surfactant concentration of 0.4% v/v and a short heating time of only 2min at 70°C were sufficient for quantitative extraction of the analyte. For the separation of the extraction phase, the resulted cloudy solution was passed through a packed trapping column that was cooled to 0?°C. The temperature of the CCT column was then increased to 25°C and the surfactant rich phase was desorbed with 400?L ethanol to be directly injected into HPLC for the analysis. The effects of different variables such as pH, surfactant concentration, cloud point temperature and time were investigated and optimum conditions were established by a central composite design (response surface) method. A limit of detection of 0.066mgL(-1) curcumin and a linear range of 0.22-100mgL(-1) with a determination coefficient of 0.9998 were obtained for the method. The average recovery and relative standard deviation for six replicated analysis were 101.0% and 2.77%, respectively. The CCT-CPE technique was faster than a conventional CPE method requiring a lower concentration of the surfactant and lower temperatures with no need for the centrifugation. The proposed method was successfully applied to the analysis of curcumin in human urine samples. PMID:24793851

Rahimi, Marzieh; Hashemi, Payman; Nazari, Fariba

2014-05-15

126

Cleanup and analysis of sugar phosphates in biological extracts by using solid-phase extraction and anion-exchange chromatography with pulsed amperometric detection.  

PubMed

A cleanup method based on anion-exchange solid-phase extraction (SPE) was developed to render biological extracts suitable for the analysis of hexose phosphates with a modified anion-exchange chromatography method and pulsed amperometric detection. The method was applied to cell extracts of Saccharomyces cerevisiae obtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the cell extract with SPE markedly improved the quality of the liquid chromatography analysis with recoveries of the sugar phosphates close to 100%. Furthermore, the method allowed for sample enrichment and the original extraction procedure could be simplified by implementing SPE early in the extraction protocol. PMID:9683509

Smits, H P; Cohen, A; Buttler, T; Nielsen, J; Olsson, L

1998-07-15

127

Novel Slow Extraction Scheme for Proton Accelerators Using Pulsed Dipole Correctors and Crystals  

SciTech Connect

Slow extraction of protons beams from circular accelerators is currently widely used for a variety of beam-based experiments. The method has some deficiencies including limited efficiency of extraction, radiation induced due to scattering on the electrostatic septa and limited beam pipe aperture, beam dynamics effects of space charge forces and magnet power supplies ripple. Here we present a novel slow extraction scheme employing a number of non-standard accelerator elements, such as Silicone crystal strips and pulsed stripline dipole correctors, and illustrate practicality of these examples at the 8 GeV proton Recycler Ring at Fermilab. The proposed method of non-resonant slow extraction of protons by bent crystals in combination with orbit fast deflectors shows great promise in simulations. We propose to initiate an R&D program in the Fermilab 8 GeV Recycler to address the key issues of the method: (a) feasibility of very short crystals - from few mm down to 0.2 mm; (b) their efficiency in the channelling and volume reflection regimes; (c) practical aspects of the fast deflectors.

Shiltsev, V.; /Fermilab

2012-05-01

128

Selective extraction of beta-blockers from biological fluids by column-switching high-performance liquid chromatography using an internal-surface phenylboronic acid precolumn.  

PubMed

A column-switching HPLC method using an internal-surface phenylboronic acid precolumn for the selective extraction of beta-blockers from biological fluids has been developed. Filtered urine and plasma samples (50 microliters) were injected onto the precolumn equilibrated with methanol-0.05 M disodium hydrogenphosphate (5:95, v/v). After the precolumn had been washed briefly, the selectively retained beta-blockers were eluted with methanol-0.05 M phosphate buffer (pH 2.0) and transferred to a reversed-phase analytical column, on which they were then separated. Even after exposure to at least 160 injections of non-treated urine and plasma samples, the retention efficiency of the precolumn was maintained with no increase in back pressure. Quantitative recoveries and good reproducibility were demonstrated with pindolol. PMID:8634760

Ohta, T; Niida, S; Nakamura, H

1996-01-12

129

Cooling of extraction electrode of an ion source in long-pulse operation.  

PubMed

Experimental studies were made on the cooling of extraction electrodes of an ion source in the case of long-pulse operation. Copper electrodes with forced water cooling pipes were tested under the condition that an ion beam of 1 to 5 A at 30 keV was extracted for up to 10 s. The average heat loading to the grid are of the electrode was as high as 130 W/cm2. This high heat flux was obtained by a set of electrodes artificially arranged to produce poor beam optics, and hence the high heat loading. Temperature of the ground electrode was measured at two points by thermocouples buried and silver brazed in it, and was kept below 230 degrees C due to a large boiling heat transfer coefficient of the cooling water. No evidences of deformation or deterioration of the electrodes was observed after repetitious beam extraction. This heat loading was still a half of that on the grid of the ion source for the JT-60 NBI. PMID:18699409

Horiike, H; Kondoh, U; Morita, H; Shirakata, H; Sugawara, T; Tanaka, S

1979-11-01

130

Pulsed electromembrane method for simultaneous extraction of drugs with different properties.  

PubMed

In the current work, a new setup including two cathodes and one anode was designed and employed for the first time for pulsed electromembrane extraction (PEME) of atenolol (ATE) and betaxolol (BET) from water, urine, and plasma samples. Because these analytes have different lipophilicities, the composition of supported liquid membrane (SLM) should be optimized for each drug and it is impossible to extract them simultaneously using common electromembrane setups. The SLMs employed for the extraction of BET and ATE were pure 2-nitrophenyl octyl ether (NPOE) and a mixture of 90% NPOE and 10% di-(2-ethylhexyl) phosphate (DEHP), respectively, which were immobilized in the pores of two different hollow fibers. An electric field of 100V was applied to transfer the analytes from the sample solution across the SLMs into acidic acceptor solutions with pH 1.0 that were located inside the lumens of hollow fibers. Preconcentration factors in the range of 69 to 363 and satisfactory repeatabilities (2.2 < relative standard deviation [RSD] < 7.4) were obtained in different matrices. The method offered a good linearity with correlations of determination (R2) higher than 0.9944 and was applied for determination and quantification of the analytes in some real samples. Finally, satisfactory results were obtained. PMID:23562379

Arjomandi-Behzad, Leila; Yamini, Yadollah; Rezazadeh, Maryam

2013-07-15

131

Manual for the thermal and hdyraulic design of direct contract spray columns for use in extracting heat from geothermal brines  

NASA Astrophysics Data System (ADS)

This report outlines the current methods being used in the thermal and hydraulic design of spray column type, direct contact heat exchangers. It provides appropriate referenced equations for both preliminary design and detailed performance. The design methods are primarily empirical and are applicable for use in the design of such units for geothermal application and for application with solar ponds. Methods for design, for both preheater and boiler sections of the primary heat exchangers, for direct contact binary powers plants are included.

Jacobs, H. R.

1985-06-01

132

Acaricidal activity of petroleum ether extract of neem (Azadirachta indica) oil and its four fractions separated by column chromatography against Sarcoptes scabiei var. cuniculi larvae in vitro.  

PubMed

The petroleum ether extract of neem oil and its four fractions separated by column chromatography was diluted at different concentrations with liquid paraffin. The acaricidal bioassay was conducted using a dipping method. The results indicated that the median lethal concentration (LC50) of the petroleum ether extract (at the concentration of 500.0ml/l) was 70.9ml/l, 24h after treatment. At concentrations of 500.0, 250.0, 125.0, 62.5 and 31.2ml/l, the median lethal times (LT50) of the petroleum ether extract were 8.7, 8.8, 10.8, 11.5 and 13.1h, respectively. Thin-layer chromatography (TLC) showed that the petroleum ether extract of neem oil separated into four fractions (F1-F4). Acaricidal activity of 68.3% and 100.0% in the F2 and F4 was confirmed. These results suggest that petroleum ether extracts of neem oil and its four fractions possess useful acaricidal activity in vitro. PMID:22349080

Deng, Yunxia; Shi, Dongxia; Yin, Zhongqiong; Guo, Jianhong; Jia, Renyong; Xu, Jiao; Song, Xu; Lv, Cheng; Fan, Qiaojia; Liang, Xiaoxia; Shi, Fei; Ye, Gang; Zhang, Wei

2012-04-01

133

The use of selective extraction chromatographic columns as an alternative to solvent extraction for the separation of uranium followed by the use of Arsenazo III as a calorimetric reagent for uranium determination  

SciTech Connect

The use of U/TEVA{reg_sign} Spec columns as an alternative to solvent extraction for separation of uranium prior to its determination by various techniques (calorimetric, phosphorescence, and mass spectroscopy) was investigated. U/TEVA{reg_sign} Spec columns have several advantages over the widely used 4-methyl-2-pentanone solvent extraction method. Among the advantages are: (1) no hazardous liquid organic waste, that creates regulatory waste disposal problems, is generated; (2) a clean separation of U from Zr, F, and fission products is obtained; (3) the sample preparation time is reduced; and (4) the exposure of analysts to ionizing radiation is reduced because the entire procedure may be performed in a hot cell using remote operations. This study also investigated the use of Arsenazo III (1,8-dihydroxynapthalene-3,6-disulfonic acid-2,7-bis [<-azo-2>-phenylarsonic acid]) as a calorimetric reagent to determine uranium concentrations over a wide range in waste streams and product streams at the Idaho Chemical Processing Plant. Process and waste stream samples were passed through a U/TEVA{reg_sign} Spec column to selectively remove the uranium. The uranium bearing fraction is compatible with the pH range for color development with Arsenazo III. Arsenazo III may be added to the uranium fraction, at a 3:1 mole ratio (Arsenazo:Uranium) at the high end of the method (10 {mu}/mL). Arsenazo III forms a highly stable complex with uranium. Stability tests from this and other studies show that the colored complex of Arsenazo III with U(VI) forms within one minute and remains stable for several hours. The complex with U(VI) varies in color with pH. However, with excess reagent, the color is varying shades of purple. Since the samples were passed through a highly selective extraction chromatographic column prior to adding the calorimetric reagent, no interferences were observed.

Miller, C.J.; Del Mastro, J.R.

1994-10-01

134

Long pulse large area beam extraction with a rf driven H{sup -}/D{sup -} source  

SciTech Connect

IPP Garching is heavily involved in the development of the rf driven H{sup -}/D{sup -} ion source for the ITER NBI. After the successful demonstration of the required physical parameters, the experimental conditions have been extended to long pulses and large area beam extraction. This paper contains descriptions of the source and power supply modifications necessitated for long pulses as well as the latest results including the first 1 h pulse. Suppression of the coextracted electron current is a key issue. Experiments with potential control, different magnetic filter fields, and cesium handling to suppress the electrons and stabilize the currents are also reported.

Kraus, W.; Falter, H.-D.; Fantz, U.; Franzen, P.; Heinemann, B.; McNeely, P.; Riedl, R.; Speth, E. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, 85740 Garching (Germany)

2008-02-15

135

Plate Performance in Liquid-Liquid Extraction.  

National Technical Information Service (NTIS)

The relative effectiveness of perforated, nozzle, and burred plates from a capacity and extraction standpoint were studied in a pulsed liquid-liquid extraction system. The experiments were conducted in a 3.8 x 10 exp -2 m diameter column using a mixture o...

R. P. Wadkins

1984-01-01

136

Continuous ultrasound-assisted extraction coupled to on line filtration-solid-phase extraction-column liquid chromatography--post column derivatisation-fluorescence detection for the determination of N-methylcarbamates in soil and food.  

PubMed

A dynamic ultrasound-assisted method for the extraction of N-methylcarbamates (oxamyl, dioxacarb, metolcarb, carbofuran, carbaryl and isoprocarb) from soils and foods is proposed. The main factors affecting the extraction efficiency have been optimised by means of a central composite design. Pure water can be used as leaching agent. A flow injection manifold coupled to the extractor allows automation of the several steps involved in the analytical process. The method allows extraction of the carbamates from soil and food at 1 microg/g spiked level, with recoveries similar to those provided by the EPA 8318 method, without degradation of the target compounds during the extraction and with drastic shortening of the time required for this step (2 min vs. 4 h). Recoveries of the target analytes were 77-95% for spiked soil and 85-101% for spiked food. The detection and quantification limits were 12 and 40 ng/g, respectively, for all analytes, except carbaryl (detection and quantification limits 3 and 10 ng/ng, respectively). The relative standard deviations for repeatability and within-laboratory reproducibility were 3.1 and 7.5%, respectively. PMID:12862371

Caballo-López, A; Luque de Castro, M D

2003-05-23

137

In vitro gastric and intestinal digestions of pulsed light-treated shrimp extracts.  

PubMed

Pulsed ultraviolet light (PUV), a novel technology most commonly used for microbial inactivation, has recently been employed to effectively mitigate food allergens in peanuts, soybean, shrimp, and almond. Putative mechanisms for the efficacy of PUV in reducing allergen reactivity include photothermal, photochemical, and photophysical effects. To date, there are no published data highlighting the effects of in vitro simulated gastric and intestinal digestion on the stability of PUV reduced allergen reactivity of food. In this study, PUV-treated shrimp extracts were subjected to simulated gastric fluid containing pepsin and simulated intestinal fluid containing trypsin and chymotrypsin, and then tested for changes in allergen potency. SDS-PAGE showed no major band deviation between undigested and digested PUV-treated shrimp extracts. IgE binding to tropomyosin remained markedly decreased as seen in Western blot analysis. Total shrimp allergen reactivity remained unchanged following in vitro peptic digestion and was markedly reduced following in vitro intestinal digestion as illustrated in indirect ELISA. The PUV reduced shrimp allergens remained at a low level under the in vitro simulated digestive conditions. The results inferred that PUV could be a potential method to create less allergenic shrimp products that would remain at a low allergen level under human gastric and intestinal digestive conditions. PMID:22278049

Yang, Wade W; Shriver, Sandra K; Chung, Si-Yin; Percival, Susan; Correll, Melanie J; Rababah, Taha M

2012-03-01

138

"In situ" extraction of essential oils by use of Dean-Stark glassware and a Vigreux column inside a microwave oven: a procedure for teaching green analytical chemistry.  

PubMed

One of the principal objectives of sustainable and green processing development remains the dissemination and teaching of green chemistry in colleges, high schools, and academic laboratories. This paper describes simple glassware that illustrates the phenomenon of extraction in a conventional microwave oven as energy source and a process for green analytical chemistry. Simple glassware comprising a Dean-Stark apparatus (for extraction of aromatic plant material and recovery of essential oils and distilled water) and a Vigreux column (as an air-cooled condenser inside the microwave oven) was designed as an in-situ extraction vessel inside a microwave oven. The efficiency of this experiment was validated for extraction of essential oils from 30 g fresh orange peel, a by-product in the production of orange juice. Every laboratory throughout the world can use this equipment. The microwave power is 100 W and the irradiation time 15 min. The method is performed at atmospheric pressure without added solvent or water and furnishes essential oils similar to those obtained by conventional hydro or steam distillation. By use of GC-MS, 22 compounds in orange peel were separated and identified; the main compounds were limonene (72.1%), ?-pinene (8.4%), and ?-terpinene (6.9%). This procedure is appropriate for the teaching laboratory, does not require any special microwave equipment, and enables the students to learn the skills of extraction, and chromatographic and spectroscopic analysis. They are also exposed to a dramatic visual example of rapid, sustainable, and green extraction of an essential oil, and are introduced to successful sustainable and green analytical chemistry. PMID:22526656

Chemat, Farid; Perino-Issartier, Sandrine; Petitcolas, Emmanuel; Fernandez, Xavier

2012-08-01

139

Determination of fluazifop-butyl and fluazifop with the use of disposable solid phase extraction columns for selective clean-up and concentration of Soxhlet soil extracts  

Microsoft Academic Search

An analytical procedure based on the solid phase extraction technology has been developed for the clean-up and concentration of Soxhlet soil extracts containing fluazifop-butyl and fluazifop by the use of a phenyl phase cartridge. No liquid-liquid partition has been used; thus the consumption of organic solvents was limited and the use of chlorinated solvents could be avoided. Quantification has been

Marco Zanco; Gerd Pfister; Antonius Kettrup

1992-01-01

140

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring  

USGS Publications Warehouse

A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

1995-01-01

141

Winogradsky Columns  

NSDL National Science Digital Library

This is an exercise about Winogradsky Columns with emphasis placed on the formation and properties of microbial biofilms. It includes background reference material, a field/lab exercise, and several applications. Applications include methods for sampling column layers and a description of how to measure the electro-chemical gradient that develops within the column. Scientific illustrations and images are included as visual references.

Lennox, John; State, Penn

142

Pulse  

MedlinePLUS

... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the patient's heart is pumping. ... rate gives information about your fitness level and health.

143

pulses  

Microsoft Academic Search

This paper reports on photoionisation loading based on ultrafast pulses of singly-ionised stron- tium ions in a linear Paul trap. We take advantage of an autoionising resonance of Sr neutral atoms to form Sr+ by two-photon absorption of femtosecond pulses at a wavelength of 431 nm. We compare this technique to electron-bombardment ionisation and observe several advantages of photoionisation. It

S. Removille; R. Dubessy; Q. Glorieux; S. Guibal; T. Coudreau; L. Guidoni; J.-P. Likforman

144

A novel non-linear recursive filter design for extracting high rate pulse features in nuclear medicine imaging and spectroscopy.  

PubMed

Applications in imaging and spectroscopy rely on pulse processing methods for appropriate data generation. Often, the particular method utilized does not highly impact data quality, whereas in some scenarios, such as in the presence of high count rates or high frequency pulses, this issue merits extra consideration. In the present study, a new approach for pulse processing in nuclear medicine imaging and spectroscopy is introduced and evaluated. The new non-linear recursive filter (NLRF) performs nonlinear processing of the input signal and extracts the main pulse characteristics, having the powerful ability to recover pulses that would ordinarily result in pulse pile-up. The filter design defines sampling frequencies lower than the Nyquist frequency. In the literature, for systems involving NaI(Tl) detectors and photomultiplier tubes (PMTs), with a signal bandwidth considered as 15 MHz, the sampling frequency should be at least 30 MHz (the Nyquist rate), whereas in the present work, a sampling rate of 3.3 MHz was shown to yield very promising results. This was obtained by exploiting the known shape feature instead of utilizing a general sampling algorithm. The simulation and experimental results show that the proposed filter enhances count rates in spectroscopy. With this filter, the system behaves almost identically as a general pulse detection system with a dead time considerably reduced to the new sampling time (300 ns). Furthermore, because of its unique feature for determining exact event times, the method could prove very useful in time-of-flight PET imaging. PMID:22964063

Sajedi, Salar; Kamal Asl, Alireza; Ay, Mohammad R; Farahani, Mohammad H; Rahmim, Arman

2013-06-01

145

Modelling of the positive column of a medium-pressure Cs-Xe dc discharge affected by a millimetre wave pulse  

NASA Astrophysics Data System (ADS)

A time-dependent zero-dimensional kinetic model of the positive column (PC) of a medium-pressure Cs-Xe dc discharge was used to gain a better insight into the physical basics of plasma techniques for imaging and control of millimetre wave (MMW) beams. The model allowed one to study the effect of MMWs on the kinetic and electrical characteristics of the spatially homogeneous PC of a Cs-Xe dc discharge. We computed the PC plasma parameters for 30 Torr and 45 Torr xenon and discharge current densities of about 0.1 A cm-2. First, the dependences of the PC parameters on caesium density were calculated in the case of no MMWs incident on the PC plasma. Then, the temporal evolution of the parameters of the PC plasma affected by a long watt-scale Ka-band MMW pulse was modelled for caesium densities of about 3 × 1012 and 5 × 1012 cm-3. The calculations showed that the electron temperature in the PC plasma attained quasisteady-state values for about 1 µs after the beginning of the MMW pulse. The electron temperature rises by 0.2-0.3 eV as the MMW intensity increases from 0 to 1 W cm-2. The rise time of the electron density decreased with an increase in the MMW intensity W from about 1 ms for W = 0.15 W cm-2 to tens of microseconds for W > 1.5 W cm-2. The steady-state values of the electron density increased in proportion to W, if W < 0.5 W cm-2. They were approximately constant for 0.5 < W < 2 W cm-2 due to the nearly full ionization of caesium atoms in the PC plasma. Efficient xenon excitation and ionization for W > 3 W cm-2 could be a cause of the microwave breakdown of the homogeneous PC plasma. The results of the modelling are in good agreement with the published experimental data.

Gitlin, M. S.; Epstein, I. L.; Lebedev, Yu A.

2013-10-01

146

Determination of the temperature dependence of water solubilities of polycyclic aromatic hydrocarbons by a generator column-on-line solid-phase extraction-liquid chromatographic method.  

PubMed

An improved dynamic coupled column liquid chromatographic (DCCLC) technique for determining water solubility data of hydrophobic compounds is presented. The technique is based on pumping water through a thermostated generator column in order to generate emulsion-free, saturated aqueous solutions of the compound under study. Through a switching valve system the solute in the aqueous solution is extracted and concentrated by an on-line solid-phase extraction process and subsequently eluted and analyzed by high performance liquid chromatography (fluorescence detection coupled to photodiode array detection). The improvements carried out to the original DCCLC technique have given rise to savings in time for the experimental work and increased sensitivity during the detection and quantification stage. Applicability of the method for studying highly hydrophobic substances is demonstrated by determining water solubility of anthracene and pyrene in the temperature range of 8.9-49.9 and 8.5-32.2 degrees C, respectively. The measured water solubilities are in good agreement with the best available literature data. The method has also been applied to the determination of water solubility of m-terphenyl, 9, 10-dihydrophenanthrene and guaiazulene, in the temperature range of 4.8-49.9, 4.8-25.0, and 4.5-29.9 degrees C, respectively. The uncertainty in the Sw values determined in this work ranged from 0.7% to 4.6%. The experimental water solubility data, as a function of temperature, are fitted to the equation In Sw = A + B/T; where Sw and T are given in mole fraction and Kelvin, respectively. PMID:12108700

Reza, Joel; Trejo, Arturo; Vera-Avila, Luz Elena

2002-06-01

147

The effect of whitecaps and foam on wind speed extraction with a pulse limited radar altimeter  

NASA Astrophysics Data System (ADS)

The effect of whitecaps and foam on wind speed extraction with a pulse limited radar altimeter has been studied using a specular point model. By modelling foam and water as a two-layer media, we have investigated the changes in reflectivity as a function of thickness using electro-magnetic field theory. Our analysis indicated a change of reflectivity from a value of 0.617 at 13.9 GHz normal incidence to a value of 0.10 for a foam thickness of less than 1 cm. The values of reflectivity computed from a two-layer model compared fairly well with these derived using an emissivity model. The modified specular point model gave an improved relationship between ?o and wind speed in comparison to Brown’s model. The Seasat altimeter’s data analysis over the Arabian sea and the Bay of Bengal gave an rms difference of 2.2 m/sec in wind speed retrieval using the present modified model and Brown’s model.

Gairola, R. M.; Pandey, P. C.

1986-07-01

148

Micro-scale membrane extraction of glyphosate and aminomethylphosphonic acid in water followed by high-performance liquid chromatography and post-column derivatization with fluorescence detector.  

PubMed

A carrier-mediated supported liquid membrane micro-extraction using single hollow fiber membrane suitable for the determination of the herbicide glyphosate and its main metabolite aminomethylphosphonic acid in water is reported. A solution of 0.20 M Aliquat-336, a cationic carrier, in di-n-hexyl ether was selected as the supported liquid. A 20 microL of 1.0 M potassium chloride as the acceptor phase was filled in the membrane lumen. The membrane was immersed in a 20 mL of pH 9.0 sample solution. After 60-min extraction, the acceptor phase was analyzed by high-performance liquid chromatography with post-column derivatization. The enrichment factors were found to be 853 and 136 for glyphosate and aminomethylphosphonic acid, respectively. The method detection limits are 0.22 microg/L for glyphosate and 3.40 microg/L for aminomethylphosphonic acid. The procedure was validated and showed good accuracy and precision over a large linear dynamic range. The validated method was tested for the analysis of both analytes in spiked groundwater with good success. PMID:18295220

Piriyapittaya, Montra; Jayanta, Siripastr; Mitra, Somenath; Leepipatpiboon, Natchanun

2008-05-01

149

Determination of Wastewater Compounds in Whole Water by Continuous Liquid-Liquid Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry  

USGS Publications Warehouse

A method for the determination of 69 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals on aquatic organisms in wastewater. This method also is useful for evaluating the effects of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are indicators of wastewater or have endocrine-disrupting potential. These compounds include the alkylphenol ethoxylate nonionic surfactants, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Wastewater compounds in whole-water samples were extracted using continuous liquid-liquid extractors and methylene chloride solvent, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 0.5 microgram per liter averaged 72 percent ? 8 percent relative standard deviation. The concentration of 21 compounds is always reported as estimated because method recovery was less than 60 percent, variability was greater than 25 percent relative standard deviation, or standard reference compounds were prepared from technical mixtures. Initial method detection limits averaged 0.18 microgram per liter. Samples were preserved by adding 60 grams of sodium chloride and stored at 4 degrees Celsius. The laboratory established a sample holding-time limit prior to sample extraction of 14 days from the date of collection.

Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.

2006-01-01

150

Automated online dual-column extraction coupled with teicoplanin stationary phase for simultaneous determination of (R)- and (S)-propranolol in rat plasma using liquid chromatography-tandem mass spectrometry.  

PubMed

An automated online sample extraction method for rat plasma was developed and validated for the quantification of (R)- and (S)-propranolol following the intravenous administration of either the racemate or the individual enantiomers at 5 mg/kg. A dual-column extraction system coupled to a chiral stationary phase (CSP) was used in conjunction with liquid chromatography-tandem mass spectrometry. In this method, two Oasis HLB extraction columns (50x1.0 mm) in parallel were used for online plasma sample purification and teicoplanin CSP (Chirobiotic T) was used for the enantiomeric separation. This method allowed the use of one of the extraction columns for purification while the other was being equilibrated. Hence, the time required for re-conditioning the extraction columns did not contribute to the total analysis time per sample, which resulted in a relatively shorter run time and higher throughput. The lower limit of detection was 0.5 ng/ml and the lower limit of quantification was 2 ng/ml for each enantiomer using 25 microl of rat plasma. The method was validated with a linear calibration curve between 2 and 2000 ng/ml for (R)- and (S)-propranolol, respectively. The intra- and inter-day precision (C.V.) was no more than 7.6% and the accuracy of the assay was between 92 and 103%. The teicoplanin CSP proved to be rugged with excellent reproducibility of chromatographic parameters. PMID:12705972

Xia, Yuan-Qing; Bakhtiar, Ray; Franklin, Ronald B

2003-05-25

151

Extraction of anthocyanins from grape by-products assisted by ultrasonics, high hydrostatic pressure or pulsed electric fields: A comparison  

Microsoft Academic Search

Extracts from grape by-products contain bioactive substances such as anthocyanins which could be used as natural antioxidants or colourants. The effect of heat treatment at 70 °C combined with the effect of different emerging novel technologies such as ultrasonics (35 KHz), high hydrostatic pressure (600 MPa) (HHP) and pulsed electric fields (3 kV cm?1) (PEF) showed a great feasibility and selectivity for

M. Corrales; S. Toepfl; P. Butz; D. Knorr; B. Tauscher

2008-01-01

152

Extracting Oxygen from Lunar Simulant Using a Transparent Furnace Pulsed Fluidized Bed  

NASA Technical Reports Server (NTRS)

In the event that humans return to the moon, utilizing the local materials will be beneficial for extended stays. Rather than transporting resources, such as oxygen, from Earth, NASA is investigating methods of extracting it from lunar regolith. One promising process is hydrogen reduction. In the hydrogen reduction process, lunar regolith is heated to 1000 C in the presence of hydrogen. The iron oxide (Fe-O) bonds, found in lunar material, are broken and the hydrogen attracts the oxygen to produce water vapor [Allen et al., 1996]. FeO + H2 (right arrow) Fe +H2O. The water vapor is then captured, cleaned, and electrolyzed. The hydrogen is recycled back to the reduction process and the oxygen is stored until consumed by an end user (propulsion, life support, etc.). To obtain a good oxygen yield, the majority of lunar regolith must be exposed to the hydrogen gas and have a high rate of heat transfer from heat source to particle. This is achieved with good solids mixing via fluidization or mechanical agitation. In Generation II of the ROxygen program, the ROxygen Team at Johnson Space Center (JSC) investigated the feasibility of gas only pulsed fluidization as the only means to mix synthetic lunar regolith (simulant) at high temperatures. Fluidized beds have been used in industry to effectively process powders for decades. They consist of gas flowing upward through a bed of particles. The stirring action continuously moves the grains around to achieve uniform mixing of gas, solids, and heat [Geldart, 1986]. A transparent furnace unit was developed by Thoughventions Unlimited LLC (TvU) to aid in the qualitative observation of the fluidization behavior at high temperatures. Multipoint thermocouples and pressure sensors provided quantitative information regarding the quality of mixing. The water produced was measured using humidity sensors and captured using a NASA designed and built condenser. Once the simulant was processed, pneumatically transporting the 'hot' simulant out of the furnace was investigated.

Oryshchyn, L.; Paz, A.; Lee, K.; Reddington, M.

2010-01-01

153

Trace determination of lenalidomide in plasma by non-extractive HPLC procedures with fluorescence detection after pre-column derivatization with fluorescamine  

PubMed Central

Background Lenalidomide (LND) is a new potent drug used for treatment of multiple myeloma. For its pharmacokinetic studies and therapeutic monitoring, a proper analytical method was required. Results In this study, a non extractive and simple pre-column derivatization procedures have been proposed, for the for trace determination of lenalidomide (LND) in human plasma by HPLC with fluorescence detection. Plasma samples were treated with acetonitrile for protein precipitation then treated with copper acetate to form stable complexes with the biogenic amines and mask their interference with the derivatization reaction of LND. Treated plasma samples containing LND was derivatized with fluorescamine (FLC) in aqueous media at ambient temperature. Separation of the derivatized LND was performed on Hypersil BDS C18 column (250?×?4.6?mm, 5??m particle size) using a mobile phase consisting of phosphate buffer (pH?4):methanol: tetrahydrofuran (70:10:20, v/v) at a flow rate of 1.0?mL/min. The derivatized samples were monitored at an emission wavelength of 495?nm after excitation at a wavelength of 382?nm. Under the optimum chromatographic conditions, a linear relationship with good correlation coefficient (r?=?0.9997, n?=?9) was found between the peak area and LND concentrations in the range of 2–100?ng/mL. The limits of detection and quantitation were 0.8 and 2.30?ng/mL, respectively. The intra- and inter-assay precisions were satisfactory and the accuracy of the method was proved. The recovery of LND from the spiked human plasma was 99.30?±?2.88. Conclusions The proposed method had high throughput as the analysis involved simple sample pre-treatment procedure and a relatively short run-time (< 15?min). The results demonstrated that the method would have a great value when it is applied in the therapeutic monitoring and pharmacokinetic studies for LND.

2013-01-01

154

Development of novel contactor for nuclear solvent extraction  

Microsoft Academic Search

For current designs of radiochemical plants, solvent-extraction contactors with no periodic maintenance like pulse column are the first choice. In addition, as costs of specialty solvents for nuclear extraction are quite high, there is a demand for operation at extreme phase ratios. Recently a novel mixer-settler was visualized and developed for this kind of service. The mixer of the novel

Shekhar Kumar; Rajnish Kumar; D. Sivakumar; M. Balamurugan; S. B. Koganti

2008-01-01

155

Lack of behavioral effects of high-peak-power microwave pulses from an axially extracted virtual cathode oscillator  

NASA Astrophysics Data System (ADS)

The development of high-power microwave (HPM) generators capable of producing extremely high-peak-power pulses for defense, commercial, and biomedical applications (1,2) has raised concern for the safety of the personnel operating such equipment. Occupational safety standards for radiofrequency exposure are based on the average-power density of irradiation and may lack applicability in situations where peak-power density is quite high while average-power density is relatively low. A battery of behavioral experiments was conducted to evaluate possible biological effects of high-power microwave (HPM) pulses generated by the Transformer Energized Megavolt Pulsed Output (TEMPO) microwave emitter, an axially extracted Virtual Cathode Oscillator (VIRCATOR). Free space electromagnetic energy in the frequency range 2.01 to 2.57 GHz (mean frequency = 2.11 + or - 0.09 SD) was radiated by conical horn in a TM01 mode. The overall pulse width was approximately 85 ns, with maximum power densities ranging as high as 24.11 kW/cm sq. per pulse (mean peak-power density = 10.79 kW/cm sq. + or - 0.35 SEM). The results suggest that peak power is not as important as average power in causing deleterious biological effects.

Hjeresen, Dennis L.; Umbarger, Kathryn O.; Klauenberg, B. Jon; Erwin, David N.

1989-11-01

156

Rapid separation of microbial lipids using solid phase extraction columns 1 Disclaimer: mention of trade names or commercial products does not constitute endorsement or recommendation for use by the US Environmental Protection Agency. 1  

Microsoft Academic Search

A method was developed to rapidly separate lipid classes commonly found in microorganisms. The method is based on the use of aminopropyl solid phase extraction columns to separate polyhydroxyalkanoates (PHA), phospholipids, sterols, triglycerides, diglycerides, monoglycerides, and steryl esters. Recoveries of all lipid classes, with the exception of PHA and sterols, ranged from 91% to greater than 99%. PHA were recovered

Holly C Pinkart; Richard Devereux; Peter J Chapman

1998-01-01

157

Stereospecific determination of amisulpride, a new benzamide derivative, in human plasma and urine by automated solid-phase extraction and liquid chromatography on a chiral column application to pharmacokinetics  

Microsoft Academic Search

Amisulpride, a drug belonging to the benzamide series, demonstrates antischizophrenic and antidepressant (antidysthymic) properties in man. For the pharmacokinetic studies of the racemic drug in man, a method of determination based on solid-phase extraction (SPE) from plasma and HPLC on a stereoselective column was developed. For this aim, one millilitre of plasma, after the addition of the internal standard, tiapride

V. Ascalone; M. Ripamonti; B. Malavasi

1996-01-01

158

Analysis of divided-pulse amplification for high-energy extraction  

NASA Astrophysics Data System (ADS)

Divided-pulse amplification employing passive coherent beam combining implementations causes a strong degradation in efficiency. In this contribution typical implementations are analyzed and a solution using an active stabilization system is presented. With this 380 fs pulses at 1.25 mJ corresponding to a peak power of 2.9 GW have been achieved demonstrating the potential of this approach.

Kienel, Marco; Klenke, Arno; Hädrich, Steffen; Eidam, Tino; Limpert, Jens; Tünnermann, Andreas

2014-03-01

159

Extraction of pulse repetition intervals from sperm whale click trains for ocean acoustic data mining.  

PubMed

The analysis of acoustic data from the ocean is a valuable tool to study free ranging cetaceans and anthropogenic noise. Due to the typically large volume of acquired data, there is a demand for automated analysis techniques. Many cetaceans produce acoustic pulses (echolocation clicks) with a pulse repetition interval (PRI) remaining nearly constant over several pulses. Analyzing these pulse trains is challenging because they are often interleaved. This article presents an algorithm that estimates a pulse's PRI with respect to neighboring pulses. It includes a deinterleaving step that operates via a spectral dissimilarity metric. The sperm whale (SW) produces trains with PRIs between 0.5 and 2 s. As a validation, the algorithm was used for the PRI-based identification of SW click trains with data from the NEMO-ONDE observatory that contained other pulsed sounds, mainly from ship propellers. Separation of files containing SW clicks with a medium and high signal to noise ratio from files containing other pulsed sounds gave an area under the receiver operating characteristic curve value of 0.96. This study demonstrates that PRI can be used for the automated identification of SW clicks and that deinterleaving via spectral dissimilarity contributes to algorithm performance. PMID:23363108

Zaugg, Serge; van der Schaar, Mike; Houégnigan, Ludwig; André, Michel

2013-02-01

160

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry  

USGS Publications Warehouse

A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

Furlong, E. T.; Vaught, D. G.; Merten, L. M.; Foreman, W. T.; Gates, P. M.

1996-01-01

161

Comparison of alkaline lysis with electroextraction and optimization of electric pulses to extract plasmid DNA from Escherichia coli.  

PubMed

The use of plasmid DNA (pDNA) as a pharmaceutical tool has increased since it represents a safer vector for gene transfer compared to viral vectors. Different pDNA extraction methods have been described; among them is alkaline lysis, currently the most commonly used. Although alkaline lysis represents an established method for isolation of pDNA, some drawbacks are recognized, such as entrapment of pDNA in cell debris, leading to lower pDNA recovery; the time-consuming process; and increase of the volume due to the buffers used, all leading to increased cost of production. We compared the concentration of extracted pDNA when two methods for extracting pDNA from Escherichia coli were used: alkaline lysis and a method based on membrane electroporation, electroextraction. At the same time, we also studied the effect of different pulse protocols on bacterial inactivation. The concentration of pDNA was assayed with anion exchange chromatography. When alkaline lysis was used, two incubations of lysis time (5 and 10 min) were compared in terms of the amount of isolated pDNA. We did not observe any difference in pDNA concentration regardless of incubation time used. In electroextraction, different pulse protocols were used in order to exceed the pDNA concentration obtained by alkaline lysis. We show that electroextraction gives a higher concentration of extracted pDNA than alkaline lysis, suggesting the use of electroporation as a potentially superior method for extracting pDNA from E. coli. In addition, electroextraction represents a quicker alternative to alkaline lysis for extracting pDNA. PMID:23831957

Haberl, Saša; Jarc, Marko; Strancar, Aleš; Peterka, Matjaž; Hodži?, Duša; Miklav?i?, Damijan

2013-11-01

162

Simultaneous determination of imidazolinone herbicides from soil and natural waters using soil column extraction and off-line solid-phase extraction followed by liquid chromatography with UV detection or liquid chromatography/electrospray mass spectroscopy.  

PubMed

This paper describes the simultaneous quantification of the imidazolinone herbicides (IMIs) imazapyr, m-imazamethabenz, p-imazamethabenz, m,p-imazamethabenz-methyl, imazethapyr, and imazaquin in two types of samples. (a) Groundwater, lake water, and river water samples were enriched by off-line solid-phase extraction with a Carbograph-1 cartridge and analyzed by reversed-phase liquid chromatography using a UV detector (lambda = 240 nm). The overall recoveries of IMIs extracted from 1 L of groundwater (fortified with 500-100 ng/L), 0.5 L of lake water (fortified with 500-100 ng/L), and 0.5 L of river water (fortified with 1000-200 ng/L) samples were not lower than 89%. The mean relative standard deviation (RSD) was 5.1% (ranging from 4.1% to 6.8%) in natural water. The detection limits were 30-39 ng/L in groundwater, 43-51 ng/L in lake water, and 55-67 ng/L in river water. The method involves confirmatory analysis by LC/ES-MS in full-scan mode. The dependence of the ion signal intensities on proton concentration in the mobile phase was investigated with a view to optimizing the sensitivity of the ES-MS detector. When LC/ES-MS was used, the limit of detection, calculated from extracted-ion current profiles (EICPs), was 4-7 ng/L for ground-water and 9-13 ng/L for river water. (b) Soil sample analysis utilized combined soil column extraction (SCE) and off-line solid phase extraction (SPE) for sample preparation, analyzing with LC/ES-MS under selected ion monitoring (SIM). Several different extractants were evaluated for the purpose of SCE optimization. The system that best optimizes the extractability IMIs from the soil was found to be the mixture CH3OH/(NH4)2CO3 (0.1 M, 50:50 v/v). The effect of IMI concentration in the matrix on recovery was evaluated. The total recovery of each IMI from soil at each of the two levels investigated ranged from 87% to 95%. Under three ion SIM conditions, the limit of detection (S/N = 3) was 0.1-0.05 ng/g in soil samples. PMID:9435470

Laganà, A; Fago, G; Marino, A

1998-01-01

163

Determination of copper, lead and iron in water and food samples after column solid phase extraction using 1-phenylthiosemicarbazide on Dowex Optipore L-493 resin.  

PubMed

A novel solid phase extraction procedure for determination of copper, lead and iron in natural water and food samples has been established in the presented work. 1-Phenylthiosemicarbazide (1-PTSC) as ligand and Dowex Optipore L-493 resin as adsorbent were used in a mini chromatographic column. Various analytical conditions for the quantitative recoveries of analyte ions including pH, amounts of adsorbent, eluent, sample volume, etc. were investigated. The recovery values for analyte ions were higher than 95%. The determination of copper, lead and iron was performed by flame atomic absorption spectrometry. The influences of some alkali, alkali earth and transition metals on the recoveries of analyte ions were investigated. The preconcentration factor was 62.5. The limit of detections of the understudied analytes (k=3, N=21) were 0.64 ?g L(-1) for copper, 0.55 ?g L(-1) for lead and 0.82 ?g L(-1) for iron. The relative standard deviation was found to be lower than 6%. The accuracy of the method was confirmed with certified reference material (GBW 07605 Tea). The method was successively applied for the determination of copper, lead and iron in water and some food samples including cheese, bread, baby food, pekmez, honey, milk and red wine after microwave digestion. PMID:21111769

Yildiz, Ozden; Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2011-02-01

164

Method of fast trace microanalysis of the chiral pesticides epoxiconazole and novaluron in soil samples using off-line flow-through extraction and on-column direct large volume injection in reversed-phase high performance liquid chromatography.  

PubMed

An analytical method combining off-line flow-through extraction of a soil micro-sample (mass around 100 mg, packed into a short HPLC glass column) and direct on-column large-volume injection (LVI up to 1.00 mL) of a methanol-water soil extract onto a conventional C18 RP HPLC column enabled fast (within 3.5 minutes) trace micro-analysis of the relatively new chiral pesticides epoxiconazole (E) and novaluron (N), respectively. Linear calibration curves were evaluated from UV detection (230 nm) data in the range from 0.1 to 5 mg/kg in three most abundant Slovak agricultural soils. LOD (confidence band) at the levels 0.08-0.11 mg/kg and LOQ 0.4-0.6 mg/kg and LOD (S/N = 3) at the levels 0.007-0.018 mg/kg and LOQ (S/N = 10) 0.024-0.060 mg/kg, respectively, of dry soil were achieved. Recovery of pesticides in the overall LVI method including flow-through 130-200 mg soil micro-sample extraction was: for epoxiconazole from 74 to 85% and from 56% to 90% for novaluron with reproducibility within +/- 6% RSD. This fast (30 min) and simple method consists of just three steps which are short column filling with a solid micro-sample; flow-through liquid extraction and direct large-volume injection RP HPLC DAD analysis. The method is prepared for automation and further analysis of enantiomers of both investigated pesticides by achiral-chiral column switching techniques. PMID:18027358

Rybár, Ivan; Góra, Robert; Hutta, Milan

2007-12-01

165

Standards Column  

Microsoft Academic Search

In this column we will review the status of the project to revise ISO 8423:1991 and the status of development of ISO 10019 on the use of consultants to help develop management systems. We will look at the ISO process for periodic systematic review of standards and look at the status of some of the recent and current reviews in

John West

2008-01-01

166

Column Chromatography  

NSDL National Science Digital Library

In this activity, learners separate the components of Gatorade using a home-made affinity column. In doing so, learners model the basic principle of affinity chromatography, a technique used to purify chemicals as well as bio-pharmaceuticals and petroleum products. This resource contains information about affinity chromatography and polarity.

Yu, Julie

2007-01-01

167

Pulsed electric field treatment of apple tissue during compression for juice extraction  

Microsoft Academic Search

The influence of pulsed electric field (PEF) simultaneous to pressure treatment on juice expression from fine-cut apple raw material has been investigated. Dependencies of specific conductivity ?, juice yield Y, instantaneous flow rate v and qualitative juice characteristics at different modes of PEF treatment are discussed. Three main compression phases were observed in a case of mechanical expression. A unified

M. I Bazhal; N. I Lebovka; E Vorobiev

2001-01-01

168

Analysis of benzalkonium chloride in the effluent from European hospitals by solid-phase extraction and high-performance liquid chromatography with post-column ion-pairing and fluorescence detection  

Microsoft Academic Search

A highly reproducible and specific method for the analysis of the quaternary ammonium compound, benzalkonium chloride, in effluents from European hospitals is presented. Benzalkonium chloride was extracted with end-capped RP-18 solid-phase cartridges and was selectively eluted. The resulting solution was analysed by high-performance liquid chromatography (HPLC). After elution from the analytical column of the HPLC system, 9,10-dimethoxyanthracene-2-sulfonate was added continuously

Klaus Kümmerer; Andreas Eitel; Ulrich Braun; Peter Hubner; Franz Daschner; Georges Mascart; Milena Milandri; Franz Reinthaler; Jan Verhoef

1997-01-01

169

Simultaneous speciation of inorganic arsenic and antimony in water samples by hydride generation-double channel atomic fluorescence spectrometry with on-line solid-phase extraction using single-walled carbon nanotubes micro-column  

Microsoft Academic Search

A new method was developed for the simultaneous speciation of inorganic arsenic and antimony in water by on-line solid-phase extraction coupled with hydride generation-double channel atomic fluorescence spectrometry (HG-DC-AFS). The speciation scheme involved the on-line formation and retention of the ammonium pyrrolidine dithiocarbamate complexes of As(III) and Sb(III) on a single-walled carbon nanotubes packed micro-column, followed by on-line elution and

Hong Wu; Xuecui Wang; Bing Liu; Yueling Liu; Shanshan Li; Jusheng Lu; Jiuying Tian; Wenfeng Zhao; Zonghui Yang

2011-01-01

170

Standards Column  

Microsoft Academic Search

In this column we will cover the Final Draft International Standard (FDIS) for ISO 9001:2008 and the rules for transition of accredited certifications to ISO 9001:2000 to the new edition. We will also review the status of the work of a new ISO\\/TC 69 Subcommittee developing ISO documents to support Six Sigma implementation. Finally we will look at the status

Jack E. West

2008-01-01

171

Standards Column  

Microsoft Academic Search

In this column we announce publication in November 2008 of ISO 9001:2008, the latest edition of the world's most popular standard. We will also discuss the introduction and support packages available from ISO\\/TC 176 for ISO 9001:2008. The forthcoming third edition of ISO\\/TS 16949, the automotive industry sector specific QMS document based on ISO 9001:2008, will be discussed. We will

Jack E. West

2009-01-01

172

PREPARATION AND CHARACTERIZATION OF MOLECULARLY IMPRINTED MONOLITHIC COLUMN FOR ON-LINE SOLIDPHASE EXTRACTION COUPLED WITH HPLC FOR DETERMINATION OF THE FLUOROQUINOLONE RESIDUES IN HONEY SAMPLES  

Microsoft Academic Search

A new ofloxacin-imprinted monolithic precolumn on-line coupling with reversed-phase high performance liquid chromatography was developed for the determination of the fluoroquinolone residues in honey samples. The molecularly imprinted monolithic column (MIP-MC) was prepared by in-situ polymerization in a stainless-steel chromatographic column, using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, chloroform and dodecanol as the mixed

Yun-Kai Lv; Cui-Ling Jia; Jing-Qi Zhang; Chao Bian; Han-Wen Sun

2012-01-01

173

Quantification of endogenous brassinosteroids in plant by on-line two-dimensional microscale solid phase extraction-on column derivatization coupled with high performance liquid chromatography-tandem mass spectrometry.  

PubMed

An on-line two-dimensional microscale solid phase extraction (2D?SPE)-on column derivatization (OCD)-high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method was developed for quantification of brassinosteroids (BRs) in plant tissues. Five BRs with widest distribution in plant species and high bioactivity (24-epibrassinolide, 24-epicastasterone, 6-deoxo-24-epicastasterone, teasterone and typhastero) were selected as target analytes. 2D?SPE column packed sequentially with phenyl boronic acid silica sorbent (the first dimension) and C18 silica sorbent (the second dimension) was used to selectively extract and enrich BRs by 110-146 times. OCD was carried out on the second dimension of 2D?SPE column with m-aminophenylboronic acid (m-APBA) as a derivatization reagent, enhancing the sensitivity of MS/MS to BRs by 13-8437 times. It was also found that pre-trap of derivatization reagent on the C18 section of 2D?SPE column could increase reaction efficiency by 3-10 times. The whole process time of the on-line system was less than 30min. The detection limits of the method for five BRs were between 1.4 and 6.6pg with RSDs less than 10%. Endogeneous BRs in tomato leaves were analyzed by using this method. Owing to the high selectivity of this on-line 2D?SPE system, BRs in plant extracts could be quantified using matrix-free standard calibration method with relative recoveries in the range of 80-124%. PMID:23702098

Wu, Qian; Wu, Dapeng; Shen, Zheng; Duan, Chunfeng; Guan, Yafeng

2013-07-01

174

Determination of priority phenolic compounds in water and industrial effluents by polymeric liquid-solid extraction cartridges using automated sample preparation with extraction columns and liquid chromatography use of liquid-solid extraction cartridges for stabilization of phenols  

Microsoft Academic Search

Fourteen phenolic compounds: catechol, phenol, 4-nitrophenol, 4-methylphenol, 2,4-dinitrophenol, 2-nitrophenol, 2-chlorophenol, 4-chlorophenol, 3-chlorophenol, 4-chloro-3-methylphenol, 2,4-dimethylphenol, 2,4-dichlorophenol, 2,4,6,-trichlorophenol and pentachlorophenol, which are included in the priority pollutants list of the US Environmental Protection Agency and in the European Union list 76\\/464, were determined in water by liquid-solid extraction (LSE) followed by liquid chromatography with UV detection (LC-UV). Three different polymeric sorbents were

M. Castillo; D. Puig; D. Barcelo´

1997-01-01

175

SOLVENT EXTRACTION OF CESIUM BY DIPICRYLAMINE. III. SEMIWORKS DEMONSTRATION  

Microsoft Academic Search

The extraction and recovery of cesium from simulated Purex waste ; solutions was successfully demonstrated in the pilot plant pulse column. Stable ; volumetric capacities as high as 670 gph\\/ft² (sum of both phases) were ; obtained for alkaline supernate-type waste; however, for efficient operation ; (transfer unit height - HTU -of two feet or less), the maximum throughput rate

1963-01-01

176

Virus movement in soil columns flooded with secondary sewage effluent.  

PubMed

Secondary sewage effluent containing about 3 X 10(4) plaque-forming units of polio virus type 1 (LSc) per ml was passed through columns 250 cm in length packed with calcareous sand from an area in the Salt River bed used for ground-water recharge of secondary sewage effluent. Viruses were not detected in 1-ml samples extracted from the columns below the 160-cm level. However, viruses were detected in 5 of 43 100-ml samples of the column drainage water. Most of the viruses were adsorbed in the top 5 cm of soil. Virus removal was not affected by the infiltration rate, which varied between 15 and 55 cm/day. Flooding a column continuosly for 27 days with the sewage water virus mixture did not saturate the top few centimeters of soil with viruses and did not seem to affect virus movement. Flooding with deionized water caused virus desorption from the soil and increased their movement through the columns. Adding CaCl2 to the deionized water prevented most of the virus desorption. Adding a pulse of deionized water followed by sewage water started a virus front moving through the columns, but the viruses were readsorbed and none was detected in outflow samples. Drying the soil for 1 day between applying the virus and flooding with deionized water greatly reduced desorption, and drying for 5 days prevented desorption. Large reductions (99.99% or more) of virus would be expected after passage of secondary sewage effluent through 250 cm of the calcareous sand similar to that used in our laboratory columns unless heavy rains fell within 1 day after the application of sewage stopped. Such virus movement could be minimized by the proper management of flooding and drying cycles. PMID:185960

Lance, J C; Gerba, C P; Melnick, J L

1976-10-01

177

Virus movement in soil columns flooded with secondary sewage effluent.  

PubMed Central

Secondary sewage effluent containing about 3 X 10(4) plaque-forming units of polio virus type 1 (LSc) per ml was passed through columns 250 cm in length packed with calcareous sand from an area in the Salt River bed used for ground-water recharge of secondary sewage effluent. Viruses were not detected in 1-ml samples extracted from the columns below the 160-cm level. However, viruses were detected in 5 of 43 100-ml samples of the column drainage water. Most of the viruses were adsorbed in the top 5 cm of soil. Virus removal was not affected by the infiltration rate, which varied between 15 and 55 cm/day. Flooding a column continuosly for 27 days with the sewage water virus mixture did not saturate the top few centimeters of soil with viruses and did not seem to affect virus movement. Flooding with deionized water caused virus desorption from the soil and increased their movement through the columns. Adding CaCl2 to the deionized water prevented most of the virus desorption. Adding a pulse of deionized water followed by sewage water started a virus front moving through the columns, but the viruses were readsorbed and none was detected in outflow samples. Drying the soil for 1 day between applying the virus and flooding with deionized water greatly reduced desorption, and drying for 5 days prevented desorption. Large reductions (99.99% or more) of virus would be expected after passage of secondary sewage effluent through 250 cm of the calcareous sand similar to that used in our laboratory columns unless heavy rains fell within 1 day after the application of sewage stopped. Such virus movement could be minimized by the proper management of flooding and drying cycles.

Lance, J C; Gerba, C P; Melnick, J L

1976-01-01

178

Methods of analysis by the U. S. Geological Survey National Water Quality Laboratory - determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring  

USGS Publications Warehouse

A method for the isolation of organonitrogen herbicides from natural water samples using solid-phase extraction and analysis by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction cartridges containing octadecyl-bonded porous silica to remove the herbicides. The cartridges are dried using carbon dioxide, and adsorbed herbicides are removed from the cartridges by elution with 1.8 milliliters of hexaneisopropanol (3:1). Extracts of the eluants are analyzed by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring of at least three characteristic ions. The method detection limits are dependent on sample matrix and each particular herbicide. The method detection limits, based on a 100-milliliter sample size, range from 0.02 to 0.25 microgram per liter. Recoveries averaged 80 to 115 percent for the 23 herbicides and 2 metabolites in 1 reagent-water and 2 natural-water samples fortified at levels of 0.2 and 2.0 micrograms per liter.

Sandstrom, Mark W.; Wydoski, Duane S.; Schroeder, Michael P.; Zamboni, Jana L.; Foreman, William T.

1992-01-01

179

The effect of temperature and flow rate on the clarification of the aqueous stevia-extract in a fixed-bed column with zeolites  

Microsoft Academic Search

Stevia is being used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour so needs to be clarified for better acceptance by consumers. Adsorption is one of the most important processes in this clarification. In this work the

I. C. C. Mantovaneli; E. C. Ferretti; M. R. Simões; C. Ferreira da Silva

2004-01-01

180

EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)  

EPA Science Inventory

Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water. ...

181

Revised Thermal Analysis of LANL Ion Exchange Column.  

National Technical Information Service (NTIS)

This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column. LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solution...

2006-01-01

182

Porous molecularly imprinted monolithic capillary column for on-line extraction coupled to high-performance liquid chromatography for trace analysis of antimicrobials in food samples.  

PubMed

A novel porous molecularly imprinted monolithic capillary column (MIMCC) based on ternary porogen was synthesized by in situ technique with sulfaquinoxaline as the template molecule. The characteristics of the MIMCC were investigated by scanning electron microscopy, infrared spectrum, thermogravimetric analysis and solvent resistance test. The saturated adsorption amount of sulfaquinoxaline on MIMCC was 2.7 times over that on the non-imprinted monolithic capillary column (NIMCC). The MIMCC also exhibited good enrichment ability to its analogs and the enrichment factors were 46-211 for five antimicrobials. High permeability and imprinting factors as well as good stability, reproducibility and long lifetime were obtained. An on-line method based on MIMCC solid-phase microextraction coupled with high-performance liquid chromatography was developed for the determination of trace antimicrobials in complex samples. The good linearity for sulfametoxydiazine, sulamethoxazole and sulfaquinoxaline was 0.05-10µg/L, the limits of detection (LODs) were 10.0-14.0ng/L. The linear range for mequindox and quinocetone were 0.10-10.0µg/L, the LODs were 20.0-27.0ng/L respectively. The recoveries were 71.0-108.2% with relative standard deviation of 1.6-8.5%, correspondingly. The results showed that MIMCC could effectively enrich antimicrobials from complex matrices. The on-line method based on MIMCC and HPLC was selective, sensitive and convenient for trace determination of antimicrobials in complex samples. PMID:24725865

Zhang, Qianchun; Xiao, Xiaohua; Li, Gongke

2014-06-01

183

The potential of downscaled dynamic column extraction for fast and reliable assessment of natural weathering effects of municipal solid waste incineration bottom ashes  

Microsoft Academic Search

There is a current worldwide interest for evaluating the potential reuse of municipal solid waste incineration (MSWI) bottom ash as a sub-base in road construction and secondary building material. Yet, there is a need for exploration of the physicochemical features of the bottom ashes to ensure environmental sustainability. To this end, batchwise water extraction as promulgated by the European norm

María Rosende; Manuel Miró; Víctor Cerdà

2008-01-01

184

Complexation Study of Humic Acids Extracted from Forest and Sahara Soils with Zinc (II) and Cadmium (II) by Differential Pulse Anodic Stripping Voltammetry (DPASV) and Conductimetric Methods  

Microsoft Academic Search

The complexation of heavy metals, present in their dissolved state at relevant trace levels, with new humic acids (HAs) isolated\\u000a from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils has been studied by differential pulse anodic stripping voltammetry\\u000a (DPASV) at a hanging mercury drop electrode and conductimetry methods. After extraction and purification, humic acids were\\u000a characterized by elemental analyses, atomic

Achour Terbouche; Safia Djebbar; Ouassini Benali-Baitich; Didier Hauchard

2011-01-01

185

Automated sample preparation with extraction columns followed by liquid chromatography-ionspray mass spectrometry interferences, determination and degradation of polar organophosphorus pesticides in water samples  

Microsoft Academic Search

The determination of polar and\\/or thermally labile organophosphorus pesticides trichlorfon, dichlorvos, dimethoate, oxydemeton-methyl, mevinphos (cis and trans), demeton-S-methyl, fenamiphos, fenitrothion, fenthion and diazinon in water samples was investigated using solid-phase extraction followed by liquid chromatography-ionspray mass spectrometry (LC-ISP-MS). Pesticides were spiked at 0.2 ?g\\/l in ground water samples and 200 ml were preconcentrated by using an ASPEC XL system. To

C Molina; P Grasso; E Benfenati; D Barceló

1996-01-01

186

Solid-phase extraction and on-disc derivatization of the major benzodiazepines in urine using enzyme hydrolysis and Toxi-Lab VC MP3 column.  

PubMed

Because of the increase in use of the newer benzodiazepines, we explored the opportunity to develop a gas chromatographic-mass spectrometric (GC-MS) method that encompasses most of the widely prescribed benzodiazepines in use today. The benzodiazepines included in our study are nordiazepam, oxazepam, temazepam, lorazepam, alpha-hydroxyalprazolam, alpha-hydroxytriazolam, desalkylflurazepam, and 2-hydroxyethylflurazepam. Using 1.0 mL of urine as the matrix, we added the enzyme Glusulase and incubated the specimens for 2 h to obtain the free drugs. The hydrolyzed samples were then loaded onto a Toxi-Lab Spec VC MP3 column containing a 15-mg disc. On-disc derivatization was accomplished by adding N-methyl-N-(t-butyldimethylsilyl) trifluroacetamide (MTBSTFA) with 1% TBDMSCI to the disc. The derivatives were then placed in a GC vial and analyzed by GC-MS in the selected ion monitoring mode. These results were then compared to confirmed positives by the traditional acid hydrolysis GC-MS method. PMID:8835665

King, J W; King, L J

1996-01-01

187

Column oriented Database Systems  

Microsoft Academic Search

Column-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subset of a table's

Daniel J. Abadi; Peter A. Boncz; Stavros Harizopoulos

2009-01-01

188

Methods of analysis and quality-assurance practices of the U.S. Geological Survey organic laboratory, Sacramento, California; determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry  

USGS Publications Warehouse

Analytical method and quality-assurance practices were developed for a study of the fate and transport of pesticides in the Sacramento-San Joaquin Delta and the Sacramento and San Joaquin River. Water samples were filtered to remove suspended parti- culate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide, and the pesticides were eluted with three 2-milliliter aliquots of hexane:diethyl ether (1:1). The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for analytes determined per 1,500-milliliter samples ranged from 0.006 to 0.047 microgram per liter. Recoveries ranged from 47 to 89 percent for 12 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.05 and 0.26 microgram per liter. The method was modified to improve the pesticide recovery by reducing the sample volume to 1,000 milliliters. Internal standards were added to improve quantitative precision and accuracy. The analysis also was expanded to include a total of 21 pesticides. The method detection limits for 1,000-milliliter samples ranged from 0.022 to 0.129 microgram per liter. Recoveries ranged from 38 to 128 percent for 21 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.10 and 0.75 microgram per liter.

Crepeau, Kathryn L.; Domagalski, Joseph L.; Kuivila, Kathryn M.

1994-01-01

189

KrF laser fusion: perform optical systems study of direct short pulse extraction. Final technical report, 26 June 1978-14 March 1981  

SciTech Connect

KrF is a prime candidate for a laser inertial confinement fusion (ICF) driver, however, there are still scaling issues to be addressed. The purpose of this program is to determine KrF performance in a regime of ICF interest both experimentally and analytically. Using a master oscillator-power amplifier (MOPA) configuration, 100J has been obtained from a five liter optical volume KrF amplifier pumped at 300 KW/cm/sup 3/ peak at the end of a 500 nsec pulse. A normalized input flux of 0.4 was required to reduce amplified spontaneous emission (ASE) to one half the free running value. A peak extraction efficiency of 0.46 was obtained under these conditions at 1 atm total pressure. The TRW kinetics model has been refined to give excellent agreement with high and low pump regimes. An integrated kinetics and pulse propagation code has also been developed and agrees well with experiment.

Bradford, Jr, R S; Betts, J A; Aprahamian, R; Livingston, P M

1981-03-01

190

Automated solid-phase extraction and high-performance liquid chromatographic determination of nitrosamines using post-column photolysis and tris(2,2'-bipyridyl) ruthenium(III) chemiluminescence.  

PubMed

A sensitive and selective post-column detection system for nitrosamines is described. The principle upon which the detector works is that UV irradiation of aqueous solutions of nitrosamines leads to cleavage of the N-NO bond. The amine generated is subsequent detected by chemiluminescence using tris(2,2'-bipyridyl) ruthenium(III), which is on-line generated by photo-oxidation of the ruthenium(II) complex in the presence of peroxydisulfate. Factors affecting the photochemical and chemiluminescent reactions were optimized to minimise their contribution to the total band-broadening. This detection system was tested for N-nitrosodimethylamine, N-nitroso-diethylamine, N-nitrosomorpholine, N-nitrosopiperidine and N-nitrosopyrrolidine, which were separated on an ODS column by isocratic reversed-phase chromatography with acetonitrile-water containing 5 mM acetate buffer at pH 4.0. A linear relationship between analyte concentration and peak area was obtained within the range 0.13-500 microg l(-1) with correlation coefficients greater than 0.9995 and detection limits of between 0.03 and 0.76 microg l(-1). Intra- and inter-day precision values of about 1.2% RSD (n = 11) and 2.5% RSD (n = 10), respectively, were obtained. The sensitivity may increase from 9 to 280 times with respect to UV detection, depending on the nitrosamine in question. An automated solid-phase extraction (SPE) system was used in conjunction with HPLC to determine nitrosamine residues in waters. Detection limits within the range 0.10-3.0 ng l(-1) were achieved for only 250 ml of sample. PMID:15988986

Pérez-Ruiz, Tomás; Martínez-Lozano, Carmen; Tomás, Virginia; Martín, Jesús

2005-06-01

191

Single Column Pyrotechnic Delay.  

National Technical Information Service (NTIS)

In the past, rocket assisted artillery projectiles used dual column pyrotechnic delays as a mechanism for igniting the rocket motor. The development of a single column pyrotechnic delay is discussed. Design methodology and results of testing are also disc...

W. W. Smith

1996-01-01

192

Simultaneous speciation of inorganic arsenic and antimony in water samples by hydride generation-double channel atomic fluorescence spectrometry with on-line solid-phase extraction using single-walled carbon nanotubes micro-column  

NASA Astrophysics Data System (ADS)

A new method was developed for the simultaneous speciation of inorganic arsenic and antimony in water by on-line solid-phase extraction coupled with hydride generation-double channel atomic fluorescence spectrometry (HG-DC-AFS). The speciation scheme involved the on-line formation and retention of the ammonium pyrrolidine dithiocarbamate complexes of As(III) and Sb(III) on a single-walled carbon nanotubes packed micro-column, followed by on-line elution and simultaneous detection of As(III) and Sb(III) by HG-DC-AFS; the total As and total Sb were determined by the same protocol after As(V) and Sb(V) were reduced by thiourea, with As(V) and Sb(V) concentrations obtained by subtraction. Various experimental parameters affecting the on-line solid-phase extraction and determination of the analytes species have been investigated in detail. With 180 s preconcentration time, the enrichment factors were found to be 25.4 for As(III) and 24.6 for Sb(III), with the limits of detection (LODs) of 3.8 ng L - 1 for As(III) and 2.1 ng L - 1 for Sb(III). The precisions (RSD) for five replicate measurements of 0.5 ?g L -1 of As(III) and 0.2 ?g L -1 of Sb(III) were 4.2 and 4.8%, respectively. The developed method was validated by the analysis of standard reference materials (NIST SRM 1640a), and was applied to the speciation of inorganic As and Sb in natural water samples.

Wu, Hong; Wang, Xuecui; Liu, Bing; Liu, Yueling; Li, Shanshan; Lu, Jusheng; Tian, Jiuying; Zhao, Wenfeng; Yang, Zonghui

2011-01-01

193

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of organophosphate pesticides in whole water by continuous liquid-liquid extraction and capillary-column gas chromatography with flame photometric detection  

USGS Publications Warehouse

A method for the isolation of 20 parent organophosphate pesticides and 5 organophosphate pesticide degradates from natural-water samples is described. Compounds are extracted from water samples with methylene chloride using a continuous liquid-liquid extractor for 6 hours. The solvent is evaporated using heat and a flow of nitrogen to a volume of 1 milliliter and solvent exchanged to ethyl acetate. Extracted compounds are determined by capillary-column gas chromatography with flame photometric detection. Single-operator derived method detection limits in three water-matrix samples ranged from 0.003 to 0.009 microgram per liter. Method performance was validated by spiking all compounds in three different matrices at three different concentrations. Eight replicates were analyzed at each concentration in each matrix. Mean recoveries of most method compounds spiked in surface-water samples ranged from 54 to 137 percent and those in ground-water samples ranged from 40 to 109 percent for all pesticides. Recoveries in reagent-water samples ranged from 42 to 104 percent for all pesticides. The only exception was O-ethyl-O-methyl-S-propylphosphorothioate, which had variable recovery in all three matrices ranging from 27 to 79 percent. As a result, the detected concentration of O-ethyl-O-methyl-S-propylphosphorothioate in samples is reported in this method with an estimated remark code. Based on the performance issue, two more compounds, disulfoton and ethion monoxon, also will be reported in this method with an estimated remark code. Estimated-value compounds, which are ?E-coded? in the data base, do not meet the performance criteria for unqualified quantification, but are retained in the method because the compounds are important owing to high use or potential environmental effects and because analytical performance has been consistent and reproducible.

Jha, Virendra K.; Wydoski, Duane S.

2003-01-01

194

Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory - Determination of Wastewater Compounds by Polystyrene-Divinylbenzene Solid-Phase Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry  

USGS Publications Warehouse

A method for the determination of 67 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals in wastewater on aquatic organisms. This method also may be useful for evaluating the impact of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are an indicator of wastewater or that have been chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclicaromatic hydrocarbons, and high-use domestic pesticides. Water samples are filtered to remove suspended particulate matter and then are extracted by vacuum through disposable solid-phase cartridges that contain polystyrene-divinylbenzene resin. Cartridges are dried with nitrogen gas, and then sorbed compounds are eluted with dichloromethane-diethyl ether (4:1) and determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 4 micrograms per liter averaged 74 percent ? 7 percent relative standard deviation for all method compounds. Initial method detection limits for single-component compounds (excluding hormones and sterols) averaged 0.15 microgram per liter. Samples are preserved by filtration, the addition of 60 grams NaCl, and storage at 4 degrees Celsius. The laboratory has established a sample-holding time (prior to sample extraction) of 14 days from the date of sample collection until a statistically accepted method can be used to determine the effectiveness of these sample-preservation procedures.

Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.; Barber, Larry B.; Burkhardt, Mark R.

2002-01-01

195

Numerical simulations of output pulse extraction from a high-power microwave compressor with a plasma switch  

NASA Astrophysics Data System (ADS)

Numerical simulations of the process of electromagnetic energy release from a high-power microwave pulse compressor comprising a gas-filled cavity and interference switch were carried out. A microwave plasma discharge in a rectangular waveguide H-plane tee was modeled with the use of the fully electromagnetic particle-in-cell code MAGIC. The gas ionization, plasma evolution, and interaction with RF fields accumulated within the compressor were simulated using different approaches provided by the MAGIC code: particle-in-cell approach accounting for electron-neutral collisions, gas conductivity model based on the concept of mobility, and hybrid modeling. The dependences of the microwave output pulse peak power and waveform on parameters that can be controlled in experiments, such as an external ionization rate, RF field amplitude, and background gas pressure, were investigated.

Shlapakovski, Anatoli; Beilin, Leonid; Bliokh, Yuri; Donskoy, Moshe; Hadas, Yoav; Schamiloglu, Edl; Krasik, Yakov E.

2014-05-01

196

Liquid chromatographic extraction medium  

DOEpatents

A method and apparatus are disclosed for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water. 1 fig.

Horwitz, E.P.; Dietz, M.L.

1994-09-13

197

Liquid chromatographic extraction medium  

DOEpatents

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

Horwitz, E. Philip (Naperville, IL); Dietz, Mark L. (Evanston, IL)

1994-01-01

198

Five Points on Columns  

PubMed Central

“Column,” like “gene,” has both conceptual and linguistic shortcomings. The simple question “what is a column” is not easy to answer and the word itself is not easy to replace. In the present article, I have selected five points, in no way comprehensive or canonical, but which may nevertheless serve as a prompt and aid for further discussions and re-evaluation. These are: that anatomical columns are not solid structures, that they are part of locally interdigitating systems, that any delimited column also participates in a widely distributed network, that columns are not an obligatory cortical feature, and that columns (as “modules”) occur widely in the brain in non-cortical structures. I focus on the larger scale macrocolumns, mainly from an anatomical perspective. My position is that cortical organization is inherently dynamic and likely to incorporate multiple processing styles. One can speculate that the distributed mappings within areas like piriform cortex may resemble at least one mode of neocortical processing strategy.

Rockland, Kathleen S.

2010-01-01

199

Investigation of the Extraction Kinetics of Uranyl Nitrate by Tributyl Phosphate: Application of the Single Drop Method in Pulsed Medium.  

National Technical Information Service (NTIS)

The investigation by the single drop technique of the uranium extraction kinetics in 3N nitric medium by tributyl phosphate diluted to 30% in a hydrocarbon, revealed the composite nature of the transfer. The solvation of uranyl nitrate by TBP, assumed to ...

B. Dinh

1987-01-01

200

Inflatable Column Structure  

NASA Technical Reports Server (NTRS)

Lightweight structural member easy to store. Billowing between circumferential loops of fiber inflated column becomes series of cells. Each fiber subjected to same tension along entire length (though tension is different in different fibers). Member is called "isotensoid" column. Serves as jack for automobiles or structures during repairs. Also used as support for temporary bleachers or swimming pools.

Hedgepeth, J. M.

1985-01-01

201

The book review column  

Microsoft Academic Search

Welcome to the Book Reviews Column. We hope to bring you at least two reviews of books every month. In this column four books are reviewed. 1. Stable Marriage and its Relation to Other Combinatorial Problems: An Intro- duction to Algorithm Analysis by Donald Knuth. Reviewed by Tim McNichol. This book uses the stable marriage problem as motivation to look

William I. Gasarch

2004-01-01

202

Support Column of Bridge  

USGS Multimedia Gallery

Support column of bridge across Struve Slough, Highway 1. Enlargement of hole where support enters the ground is an effect of lateral shaking, which caused the concrete to break up where the column joined the bridge and was instrumental in the roadbed collapse....

2009-01-26

203

Development and validation of a multi-residue method for pesticide determination in honey using on-column liquid-liquid extraction and liquid chromatography-tandem mass spectrometry.  

PubMed

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran, Methiocarb, Pirimicarb, Dimethoate, Fipronil, Imidacloprid; herbicides: Amidosulfuron, Rimsulfuron, Atrazine, Simazine, Chloroturon, Linuron, Isoxaflutole, Metosulam; fungicides: Diethofencarb) and 2 metabolites (Methiocarb sulfoxide and 2-Hydroxytertbutylazine) in honey. This method is based on an on-column liquid-liquid extraction (OCLLE) using diatomaceous earth as inert solid support and liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS). Method specificity is ensured by checking retention time and theoretical ratio between two transitions from a single precursor ion. Linearity is demonstrated all along the range of concentration that was investigated, from 0.1 to 20 ng g(-1) raw honey, with correlation coefficients ranging from 0.921 to 0.999, depending on chemicals. Recovery rates obtained on home-made quality control samples are between 71 and 90%, well above the range defined by the EC/657/2002 document, but in the range we had fixed to ensure proper quantification, as levels found in real samples could not be corrected for recovery rates. Reproducibility is found to be between 8 and 27%. Calculated CCalpha and CCbeta (0.0002-0.943 ng g(-1) for CCalpha, and 0.0002-1.232 ng g(-1) for CCbeta) show the good sensitivity attained by this multi-residue analytical method. The robustness of the method has been tested in analyzing more than 100 raw honey samples collected from different areas in Belgium, as well as some wax and bee samples, with a slightly adapted procedure. PMID:17416380

Pirard, C; Widart, J; Nguyen, B K; Deleuze, C; Heudt, L; Haubruge, E; De Pauw, E; Focant, J-F

2007-06-01

204

Sensitive high-performance anion-exchange chromatographic determination of paeoniflorin and albiflorin by pulsed amperometric detection after solid-phase extraction.  

PubMed

We developed a method to simultaneously determine paeoniflorin and albiflorin levels using high-performance anion-exchange liquid chromatography with pulsed amperometric detection (HPAEC-PAD). The main principle of our method includes solid-phase extraction step using Amberlite XAD-2 sorbent to remove sugars and to selectively determine glycosides by PAD. Under these conditions, the linear dynamic range was 0.01-100 microg/mL, and the albiflorin and paeoniflorin detection limits (S/N=3) were 5 and 10 pg, respectively. The intra- and inter-day precisions (RSDs) were <5.07%, and the average recoveries from Paeoniae Radix and Si-ni-san ranged from 97.12 to 101.15%. Our method showed high selectivity, high sensitivity, and good repeatability for analyzing albiflorin and paeoniflorin in oriental medicinal preparation. PMID:20599203

Sim, Hee-Jung; Jeong, Ji-Seon; Kwon, Ha-Jeong; Lee, Yong-Moon; Hong, Seon-Pyo

2010-08-01

205

Speciation analysis of organotin compounds in human urine by headspace solid-phase micro-extraction and gas chromatography with pulsed flame photometric detection.  

PubMed

A new headspace solid-phase micro-extraction (HS-SPME) method followed by gas chromatography with pulsed flame photometric detection (GC-PFPD) analysis has been developed for the simultaneous determination of 11 organotin compounds, including methyl-, butyl-, phenyl- and octyltin derivates, in human urine. The methodology has been validated by the analysis of urine samples fortified with all analytes at different concentration levels, and recovery rates above 87% and relative precisions between 2% and 7% were obtained. Additionally, an experimental-design approach has been used to model the storage stability of organotin compounds in human urine, demonstrating that organotins are highly degraded in this medium, although their stability is satisfactory during the first 4 days of storage at 4 °C and pH=4. Finally, this methodology was applied to urine samples collected from harbor workers exposed to antifouling paints; methyl- and butyltins were detected, confirming human exposure in this type of work environment. PMID:24840433

Valenzuela, Aníbal; Lespes, Gaëtane; Quiroz, Waldo; Aguilar, Luis F; Bravo, Manuel A

2014-07-01

206

Revised Thermal Analysis of LANL Ion Exchange Column  

Microsoft Academic Search

This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column.1 LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solutions. The Defense Nuclear Facilities Safety Board has requested an updated analysis to calculate maximum temperatures for higher resin loading capacities obtained with a new

Laurinat

2006-01-01

207

OPTIMIZED DETERMINATION OF TRACE JET FUEL VOLATILE ORGANIC COMPOUNDS IN HUMAN BLOOD USING IN-FIELD LIQUID-LIQUID EXTRACTION WITH SUBSEQUENT LABORATORY GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS AND ON-COLUMN LARGE VOLUME INJECTION  

EPA Science Inventory

A practical and sensitive method to assess volatile organic compounds (VOCs) from JP-8 jet fuel in human whole blood was developed by modifying previously established liquid-liquid extraction procedures, optimizing extraction times, solvent volume, specific sample processing te...

208

ICPSEF: a user's manual for the computer mathematical model of the ICPP purex solvent extraction system  

SciTech Connect

A computer-based mathematical program, ICPSEF, was developed for the first-cycle extraction system at the Idaho Chemical Processing Plant (ICPP). At the ICPP, spent nuclear fuels are processed to recover unfissioned uranium. The uranium is recovered from aqueous solutions in a pulse column, solvent extraction system using tributyl phosphate (TBP) solvent (purex process). A previously developed SEPHIS-MOD4 computer program was added to and modified to provide a model for the ICPP system. Major modifications included addition of: (1) partial theoretical stages to permit more accurate modeling of ICPP columns, (2) modeling ammonium hydroxide neutralization of nitric acid in a scrubbing column, and (3) equilibrium data for 5 to 10 vol % TBP. The model was verified by comparison with actual operating data. Detailed instructions for using the ICPSEF model and sample results of the model are included.

Bendixsen, C L

1982-11-01

209

A Column Dispersion Experiment.  

ERIC Educational Resources Information Center

Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

Corapcioglu, M. Y.; Koroglu, F.

1982-01-01

210

Columns in Clay  

ERIC Educational Resources Information Center

This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

Leenhouts, Robin

2010-01-01

211

The pulse sorting transform  

Microsoft Academic Search

A modification of conventional Fourier transforms is presented. This modification is called the pulse sorting transform (PST) and is useful in extracting information from signals comprised of interleaved pulse trains. A brief derivation of the PST from the conventional transform is presented, followed by theorems that describe the PST's properties. Several examples of how the PST can be an effective

K. C. Overman; D. F. Mix; J. A. Lookadoo

1990-01-01

212

Acoustic Interaction with the Positive Column of a Neon Glow Discharge.  

National Technical Information Service (NTIS)

Compressive acoustic pulses were produced by an impulsive abnormal-glow discharge and the interaction of these pulses with the positive column of a dc neon glow discharge was studied. The acoustic pulses are analyzed and are found to be infinitesimal ampl...

R. D. S. Melville

1967-01-01

213

Modified Purex first-cycle extraction for neptunium recovery  

SciTech Connect

A new PUREX first-cycle flowsheet was devised to enhance the extraction yield of neptunium at the extraction step of this cycle. Simulation results (using a qualified process-simulation tool), le d to raising the nitric acid concentration of the feed from 3 M to 4.5 M to allow extraction of more than 99% of the neptunium. This flowsheet was operated in the shielded process cell of ATALANTE facility using pulsed columns and mixer-settlers banks. A 15 kg quantity of genuine oxide fuel of average burn up of 52 GWd/t with cooling time of nearly five years was treated, and the neptunium extraction yield obtained was greater than 99.6%. (authors)

Dinh, Binh; Moisy, Philippe; Baron, Pascal; Calor, Jean-Noel; Espinoux, Denis; Lorrain, Brigitte; Benchikouhne-Ranchoux, Magali [Departement de radiochimie et procedes, Commissariat a l'energie atomique, Centre de Valrho BP 17171 30207, Bagnols-sur-Ceze CEDEX (France)

2008-07-01

214

Development of novel contactor for nuclear solvent extraction  

SciTech Connect

For current designs of radiochemical plants, solvent-extraction contactors with no periodic maintenance like pulse column are the first choice. In addition, as costs of specialty solvents for nuclear extraction are quite high, there is a demand for operation at extreme phase ratios. Recently a novel mixer-settler was visualized and developed for this kind of service. The mixer of the novel contactor is based on rotated helical tubes and does not involve any mechanical moving part. Mass-transfer runs were carried out with aqueous nitric acid and 30% TBP solvent at A/O of 0.25-200 (in extraction) and A/O of 0.25-10 (in back-extraction mode). The developed contactor exhibited nearly 100% efficiency for all the cases. (authors)

Kumar, Shekhar; Kumar, Rajnish; Sivakumar, D.; Balamurugan, M.; Koganti, S.B. [Reprocessing R and D Division, Reprocessing Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2008-07-01

215

Extracting Information on Rain-Induced Pulses of Ecosystem Respiration across Scales Spanning the Plot, Canopy and Planetary Boundary Layer (Invited)  

NASA Astrophysics Data System (ADS)

Semi-arid ecosystems experience huge pulses in respiration, following rain events. Here we characterize the dynamics of these rain-induced pulses by examining field-scale flux measurements from an annual grassland and oak savanna understory that consisted of 50 pulse events collected from over 18 site-years of measurements. We examine this problem in terms of antecedent conditions (e.g. number of prior pulses, exposure to sunlight) and current conditions (amount of rain, amount of dead vegetation). Causative explanations are provided by a set of laboratory and field manipulation studies on litter samples that were exposed to different levels of rain and sunlight--our working hypothesis is that the magnitude of the respiration pulse is modulated by differing degrees of photodegradation. To understand the regional extent of the pulses, we interpret time courses in CO2 concentration with a planetary boundary layer box model. The magnitude of the rain-induced respiration pulses is a function of the exposure of litter to sunlight, so greater pulses emanate from an open grassland than the understory of a savanna. These pulses can result in CO2 effluxes that approach 8 gC m-2 d-1, and these effluxes remain elevated, above background, for up to 20 days. We find that the pulses are regional in nature because they can cause a sudden jump in CO2 in the well-mixed planetary boundary layer of over 30 ppm.

Baldocchi, D. D.; Ma, S.; Hatala, J.; Giolio, B.

2010-12-01

216

Bubble column bioreactors  

Microsoft Academic Search

The present article investigates the behavior of bubble column bioreactors with yeast culture media in the absence of cells.\\u000a To aid in the assessment of these reactors the following properties were estimated and partly theoretically treated: relative\\u000a mean gas hold-up, bubble swarm velocity, bubble size, gas\\/liquid interfacial area, energy requirement for aeration, oxygen\\u000a transfer coefficient across the gas\\/liquid interface and

K. Schügerl; J. Lücke; U. Oels

217

Preconcentration of lead complexed with O, O-diethyl-dithiophosphate by column solid-phase extraction using different sorbents in a flow injection system coupled to a flame atomic absorption spectrometer  

Microsoft Academic Search

A comparative study of C18 immobilized on silica, activated carbon and a polyurethane foam, as sorbents for Pb complexed with O,O-diethyl-dithiophosphate in a flow injection preconcentration system is reported. The complex was formed in 1.0 M HCl medium and processed in a simple system using a peristaltic pump, a manual injector–commutator and a mini-column filled with the sorbent. Using ethanol

Sueli Pércio Quináia; José Bento Borba da Silva; Maria do Carmo Ezequiel Rollemberg; Adilson José Curtius

2001-01-01

218

In-situ differential pulse anodic stripping voltammetry combined with hollow fiber-based liquid-three phase micro extraction for determination of mercury using Au-nanoparticles sol-gel modified Pt-wire.  

PubMed

A new method has been proposed based on hollow fiber-based liquid three-phase micro extraction and in-situ differential pulse anodic stripping voltammetry (DPASV) for the micro extraction and quantification of mercury(II) ions. Different factors affecting the liquid-three phases micro extraction, including organic solvent, pH of the donor and acceptor phases, concentration of the complexing agent, extraction time, and stirring rate were investigated and the optimal extraction conditions were established. Three microelectrodes designed and constructed for this study were inserted into the two ends of a hollow fiber inside the acceptor solution, and then voltammetric analysis was performed in-situ during the extraction time. After 1600 s, final stable signal was used for the analytical applications. Under the optimized conditions, an enrichment factor of 277 was achieved and the relative standard deviation (R.S.D.) of the method was 6.2% (n=5). The calibration curve was obtained in the range of 0.2-30.0 nmol L(-1) Hg(II) with a reasonable linearity (R(2)>0.9880) and a limit of detection of 0.06 nmol L(-1). Finally, the applicability of the proposed method was evaluated by extraction and determination of mercury in real samples such as fish and rice. PMID:22967561

Ensafi, Ali A; Allafchian, Ali R; Saraji, M; Farajmand, B

2012-09-15

219

Column Switching and Liquid Chromatographic Technique for the Rapid Determination of Fenoxycarb Insecticide Residues in Apples  

Microsoft Academic Search

Fenoxycarb residues are analyzed by column switching and reversed-phase high performance liquid chromatography (RP-HPLC). The active ingredient is extracted from apples on a silica gel column using a n-hexane - diethyl ether mixture. The eluate is evaporated, dry residue dissolved in acetonitrile-deionized water, and injected into the liquid chromatograph with a column switching system (C8 columns), and a UV-photodiode array

M. Michel; A. Krause; B. Buszewski

220

The tallest column — optimality revisited  

Microsoft Academic Search

The problem of the optimal design of the tallest unloaded column under selfweight is revisited with a view towards clarifying the optimality of the design proposed by Keller and Niordson (The Tallest Column, J. Math. Mech. 16 (1966), pp. 433–446). The height of the tallest column is related to the first eigenvalue of a Sturm-Liouville operator. Since the operator associated

C. Maeve McCarthy

1999-01-01

221

Tests on slender composite columns  

Microsoft Academic Search

This paper describes two series of load tests on slender composite columns: eight tests on concrete filled rectangular hollow steel section columns and seven tests on concrete encased rolled steel joist columns, both with end eccentricities producing moments other than single curvature bending. In all tests, normal strength concrete of grade C25\\/30 and low strength steel of grade S275 were

Yong Wang

1999-01-01

222

Method of analysis and quality-assurance practices for determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry at the U.S. Geological Survey California District Organic Chemistry Laboratory, 1996-99  

USGS Publications Warehouse

A method of analysis and quality-assurance practices were developed to study the fate and transport of pesticides in the San Francisco Bay-Estuary by the U.S. Geological Survey. Water samples were filtered to remove suspended-particulate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide and the pesticides were eluted with three cartridge volumes of hexane:diethyl ether (1:1) solution. The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for pesticides ranged from 0.002 to 0.025 microgram per liter for 1-liter samples. Recoveries ranged from 44 to 140 percent for 25 pesticides in samples of organic-free reagent water and Sacramento-San Joaquin Delta and Suisun Bay water fortified at 0.05 and 0.50 microgram per liter. The estimated holding time for pesticides after extraction on C-8 solid-phase extraction cartridges ranged from 10 to 257 days.

Crepeau, Kathryn L.; Baker, Lucian M.; Kuivila, Kathryn M.

2000-01-01

223

Analysis of finishing reactive distillation columns  

SciTech Connect

In this paper, a novel method to deal with the design and the synthesis of finishing reactive distillation columns with one reactive core, two rectifying sections, and one stripping section is presented. The attention of the work is concentrated on three subjects: (1) the feasibility of a given separation at both finite and total reflux operation; (2) the minimum energy demand operation; (3) the distribution of the reaction between the reactor and the finishing reactive column. The design problem presents the same grade of difficulty as that found in the design of conventional extractive columns. A geometric based method is used to explain key features of reactive distillation. Here, the relation between the reaction yield and the distillate flow rate plays a role similar to that of the entrainer flow in extractive distillation. Hence, special attention is given to the behavior of the profiles inside the rectifying section below the reactive core. The methodology is illustrated using the well-known MTBE case study.

Espinosa, J.; Aguirre, P.; Frey, T.; Stichlmair, J. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl A fuer Verfahrenstechik] [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl A fuer Verfahrenstechik

1999-01-01

224

New validated high-performance liquid chromatographic method for simultaneous analysis of ten flavonoid aglycones in plant extracts using a C18 fused-core column and acetonitrile-tetrahydrofuran gradient.  

PubMed

An HPLC method of high resolution has been developed and validated for the simultaneous determination of ten prominent flavonoid aglycones in plant materials using a fused-core C18-silica column (Ascentis® Express, 4.6 mm × 150 mm, 2.7 ?m). The separation was accomplished with an acetonitrile-tetrahydrofuran gradient elution at a flow rate of 1 mL/min and temperature of 30°C. UV spectrophotometric detection was employed at 370 nm for flavonols (quercetin [QU], myricetin [MY], isorhamnetin [IS], kaempferol [KA], sexangularetin [SX], and limocitrin [LM]) and 340 nm for flavones (apigenin [AP], acacetin [AC], chrysoeriol [CH], and luteolin [LU]). The high resolution of critical pairs QU/LU (10.50), QU/CH (3.40), AP/CH (2.51), SX/LM (2.30), and IS/KA (2.70) was achieved within 30.3 min. The observed column back pressure was less than 4300 psi, thus acceptable for conventional HPLC equipment. The method was sensitive enough having LODs of 0.115-0.525 ng and good linearity (r > 0.9999) over the test range. The precision values, expressed as RSD values, were <7.5%, and the accuracy was in the range of 95.3-100.2% for all analytes except MY (73.8%). The method was successfully employed for the determination of flavonoids in several medicinal plants, such as Ginkgo biloba, Betula pendula, and a variety of Sorbus species. PMID:22807401

Olszewska, Monika A

2012-09-01

225

Columbia Library Columns  

NSDL National Science Digital Library

Most institutions keep records of their various activities, and university libraries are no different. Columbia University's Library published its in-house "Columbia Library Columns" from 1951 to 1996. Over the years it was edited by several people, including Kenneth A. Lohf, Jean Ashton, and Michael Stoller. This remarkable archive brings together the entire run; all told, it includes 135 issues and 6,900 pages. Visitors can browse the table of contents, peruse a list of all the volumes, and also perform a detailed keyword search. The Selected Articles of Interest collection brings together some of the most compelling offerings, such as "The John Jay Papers," "Instructing Women: Conduct Books in the Plimpton Library," and a rather intriguing piece from 1978 titled "The Library of the Future Has Books."

226

Antioxidant activity of sesame cake extract  

Microsoft Academic Search

Sesame cake was extracted with methanol to obtain a crude antioxidant extract. The qualitative and quantitative analysis of antioxidants\\/lignans present in the extract was carried out by reverse phase high performance liquid chromatography (HPLC) using a C18 column. In this study, sesame cake was also subjected to successive extractions with solvents of differing polarity to get a purified antioxidant extract

K. P. Suja; A. Jayalekshmy; C. Arumughan

2005-01-01

227

Five-Layer Density Column  

NSDL National Science Digital Library

In this activity, learners can create five-layer density columns by employing one of three (or all) methods. Method 1 gives the names of the liquids and the order for adding them, and its goal is to directly construct the density column without any experimentation. Method 2 assumes names and densities of the five materials to be unknown, and involves open-ended experimenting, with few instructions, to construct the column. Method 3 also assumes names and densities of the materials to be unknown, and outlines a systematic way to approach the experimentation involved in constructing the column. Learners complete data tables and analyze the densities of the substances.

Rathjen, Don

2005-01-01

228

Compact electron beam focusing column  

SciTech Connect

A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

2001-07-13

229

45. MAIN MEETING ROOM COLUMNS. Ends of gallery columns identified ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

45. MAIN MEETING ROOM COLUMNS. Ends of gallery columns identified at the time of removal for transfer to the George School for re-erection. The stamp reads, 'REMOVED FROM 12th ST. MTG HSE PHILA 1972'. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

230

Dorsal column stimulator applications  

PubMed Central

Background: Spinal cord stimulation (SCS) has been used to treat neuropathic pain since 1967. Following that, technological progress, among other advances, helped SCS become an effective tool to reduce pain. Methods: This article is a non-systematic review of the mechanism of action, indications, results, programming parameters, complications, and cost-effectiveness of SCS. Results: In spite of the existence of several studies that try to prove the mechanism of action of SCS, it still remains unknown. The mechanism of action of SCS would be based on the antidromic activation of the dorsal column fibers, which activate the inhibitory interneurons within the dorsal horn. At present, the indications of SCS are being revised constantly, while new applications are being proposed and researched worldwide. Failed back surgery syndrome (FBSS) is the most common indication for SCS, whereas, the complex regional pain syndrome (CRPS) is the second one. Also, this technique is useful in patients with refractory angina and critical limb ischemia, in whom surgical or endovascular treatment cannot be performed. Further indications may be phantom limb pain, chronic intractable pain located in the head, face, neck, or upper extremities, spinal lumbar stenosis in patients who are not surgical candidates, and others. Conclusion: Spinal cord stimulation is a useful tool for neuromodulation, if an accurate patient selection is carried out prior, which should include a trial period. Undoubtedly, this proper selection and a better knowledge of its underlying mechanisms of action, will allow this cutting edge technique to be more acceptable among pain physicians.

Yampolsky, Claudio; Hem, Santiago; Bendersky, Damian

2012-01-01

231

Effect of soil permeability on virus removal through soil columns.  

PubMed Central

Laboratory experiments were performed on four different soils, using 100 cm long columns, to determine the extent of virus movement when wastewater percolated through the soils at various hydraulic flow rates. Unchlorinated secondary sewage effluent seeded with either poliovirus type 1 (strain LSc) or echovirus type 1 (isolate V239) was continuously applied to soil columns for 3 to 4 days at constant flow rates. Water samples were extracted daily from ceramic samplers at various depths of the column for the virus assay. The effectiveness of virus removal from wastewater varied greatly among the different soil types but appeared to be largely related to hydraulic flow rates. At a flow rate of 33 cm/day, Anthony sandy loam removed 99% of seeded poliovirus within the first 7 cm of the column. At flow rates of 300 cm/day and above, Rubicon sand gave the poorest removal of viruses; less than 90% of the seeded viruses were removed by passage of effluent through the entire length of the soil column. By linear regression analyses, the rate of virus removal in soil columns was found to be negatively correlated with the flow of the percolating sewage effluent. There was no significant difference in rate of removal between poliovirus and echovirus in soil columns 87 cm long. The rate of virus removal in the upper 17 cm of the soil column was found to be significantly greater than in the lower depths of the soil column. This study suggests that the flow rate of water through the soil may be the most important factor in predicting the potential of virus movement into the groundwater. Furthermore, the length of the soil column is critical in obtaining useful data to predict virus movement into groundwater.

Wang, D S; Gerba, C P; Lance, J C

1981-01-01

232

Employing anatomical knowledge in vertebral column labeling  

NASA Astrophysics Data System (ADS)

The spinal column constitutes the central axis of human torso and is often used by radiologists to reference the location of organs in the chest and abdomen. However, visually identifying and labeling vertebrae is not trivial and can be timeconsuming. This paper presents an approach to automatically label vertebrae based on two pieces of anatomical knowledge: one vertebra has at most two attached ribs, and ribs are attached only to thoracic vertebrae. The spinal column is first extracted by a hybrid method using the watershed algorithm, directed acyclic graph search and a four-part vertebra model. Then curved reformations in sagittal and coronal directions are computed and aggregated intensity profiles along the spinal cord are analyzed to partition the spinal column into vertebrae. After that, candidates for rib bones are detected using features such as location, orientation, shape, size and density. Then a correspondence matrix is established to match ribs and vertebrae. The last vertebra (from thoracic to lumbar) with attached ribs is identified and labeled as T12. The rest of vertebrae are labeled accordingly. The method was tested on 50 CT scans and successfully labeled 48 of them. The two failed cases were mainly due to rudimentary ribs.

Yao, Jianhua; Summers, Ronald M.

2009-02-01

233

Preconcentration of lead complexed with O,O-diethyl-dithiophosphate by column solid-phase extraction using different sorbents in a flow injection system coupled to a flame atomic absorption spectrometer.  

PubMed

A comparative study of C(18) immobilized on silica, activated carbon and a polyurethane foam, as sorbents for Pb complexed with O,O-diethyl-dithiophosphate in a flow injection preconcentration system is reported. The complex was formed in 1.0 M HCl medium and processed in a simple system using a peristaltic pump, a manual injector-commutator and a mini-column filled with the sorbent. Using ethanol as eluent, the richest 150-mul fraction was collected and measured (after discarding 150, 200 and 0 mul for the activated carbon, foam and C(18), respectively) by flame atomic absorption spectrometry. The optimum concentration of the complexing agent was 0.05% m/v for C(18) and 0.2% m/v for the activated carbon and the polyurethane foam. The best sample loading flow rate was 4.0 ml min(-1) for the activated carbon and 2.0 ml min(-1) for C(18) and the polyurethane foam, while the best elution flow rate was 1.0 ml min(-1) (activated carbon) and 0.6 ml min(-1) (C(18) and foam). It was found that beyond a certain loading sample volume, for a constant analyte mass, the signal decreased. The maximum loading sample volume, for a constant analyte mass, before the signal started to decrease, was 50 ml for the activated carbon and 150 ml for the other materials. By processing 25 ml, the enrichment factors were 23, 55 and 166 for the activated carbon, foam and C(18), respectively. The best limit of detection (3sigma) was 0.3 mug l(-1) for the C(18) (1.2 mug l(-1) for the foam and 3 mug l(-1) for the activated carbon). As shown, the C(18) has a much superior retention performance in comparison to the other two materials. PMID:18968291

Quináia, S P; Borba da Silva, J B; Ezequiel Rollemberg, M do C; Curtius, A J

2001-05-30

234

Solid-phase extraction of galloyl- and caffeoylquinic acids from natural sources (Galphimia glauca and Arnicae flos) using pure zirconium silicate and bismuth citrate powders as sorbents inside micro spin columns.  

PubMed

Galloyl- and caffeoylquinic acids are among the most important pharmacological active groups of natural compounds. This study describes a pre-step in isolation of some selected representatives of these groups from biological samples. A selective solid-phase extraction (SPE) method for these compounds may help assign classes and isomer designations within complex mixtures. Pure zirconium silicate and bismuth citrate powders (325 mesh) were employed as two new sorbents for optimized SPE of phenolic acids. These sorbents possess electrostatic interaction sites which accounts for additional interactions for carbon acid moieties as compared to hydrophilic and hydrophobic sorbents alone. Based on this principle, a selective SPE method for 1,3,4,5-tetragalloylquinic acid (an anti-HIV and anti-asthamatic agent) as a starting compound was developed and then deployed upon other phenolic acids with success. The recoveries and selectivities of both sorbents were compared to most commonly applied and commercially available sorbents by using high performance liquid chromatography. The nature of interaction between the carrier sorbent and the acidic target molecules was investigated by studying hydrophilic (silica), hydrophobic (C18), mixed-mode (ionic and hydrophobic: Oasis(®) MAX) and predominantly electrostatic (zirconium silicate) materials. The newly developed zirconium silicate and bismuth citrate stationary phases revealed promising results for the selective extraction of galloyl- and caffeoylquinic acids from natural sources. It was observed that zirconium silicate exhibited maximum recovery and selectivity for tetragalloylquinic acid (84%), chlorogenic acid (82%) and dicaffeoylquinic acid (94%) among all the tested sorbents. PMID:23831490

Hussain, Shah; Schönbichler, Stefan A; Güzel, Yüksel; Sonderegger, Harald; Abel, Gudrun; Rainer, Matthias; Huck, Christian W; Bonn, Günther K

2013-10-01

235

The Tevatron Extraction Pulser  

Microsoft Academic Search

The Tevatron QXR (Quadrupole Extraction Regulator) power supply is a linear current pulser combined with a dc transistor regulator. The pulser produces programmable current pulses of up to 250 amps with a maximum duration of 12 ms and a maximum voltage drive of +200\\/-250 volts. Its fastest repetition rate is 1 Hz. Between pulses a single power transistor regulator maintains

H. Pfeffer

1985-01-01

236

Performance analysis of rotating disc contactor (RDC) column  

NASA Astrophysics Data System (ADS)

Liquid-liquid extraction is one of the most important separation processes. Different kinds of liquid-liquid extrator such as Rotating Disc Contactor (RDC) Column being used in industries. The study of liquid-liquid extraction in an RDC column has be come a very important subject to be discussed not just amongst chemical engineers but mathematicans as well. In this study, the performance of small diameter column RDC using the chemical system involving cumene/isobutryric asid/water are analyzed by the method of design of the experiments (DOE). DOE are applied to estimated the effect of four independent variable; protor speed, flow rate, concentration of continuous inlet and dispersed inlet and their interaction factor to detemine the most significant factor that effect the concentration of continuous and dispersed outlet as output parameters.

Aiffah, Wan Nurul; Aisyah, Siti; Fashihah, Nor; Anuar, Khairil

2014-06-01

237

Solute transport through large uniform and layered soil columns  

NASA Astrophysics Data System (ADS)

Solute transport experiments are often conducted with homogeneous soils, whereas transport in real situations takes place in heterogeneous soils. An experiment was conducted to compare unsaturated solute transport through uniform and layered soils. Pulse inputs of tritiated water, bromide and chloride were applied under steady flow conditions to the tops of two large (0.95 m diameter by 6 m deep) soil columns. One column was uniformly filled with loamy fine sand and the other filled with alternating 20-cm-thick layers of loamy fine sand and silty clay loam. Soil solution samples were collected during the experiment with suction candles installed at various depths in the columns. Solute transport parameters were estimated by fitting the convection-dispersion equation to the observed breakthrough curves for each solute at various depths in each column. The match between the resulting calibrated curves and the experiment was better for the layered soil column than for the uniform soil column. The results displayed no clear relationship between the dispersion coefficients and depth for any of the tracers for either column. However, dispersivities were greater in the uniform column (3.5 cm) than in the layered column (1.2 cm), while retardation factors for bromide and chloride were similar (0.8 and 0.83, respectively, for the uniform and layered columns). A retardation factor less than one is attributed to anion exclusion. There was evidence of preferential flow in the uniform soil column. The peak concentrations at 5 m depth were greater than those observed at 4 m. Such behavior is inconsistent with one-dimensional flow. Similar results were observed in an experiment performed 3.5 years earlier using the same soil column and approximately the same flow rates, but using a different tracer and associated chemical analysis, different soil saturation prior to the execution of the experiment, and different experimental personnel. This supports the thesis that the anomalous behavior is due to some form of preferential flow rather than due to experimental error.

Porro, I.; Wierenga, P. J.; Hills, R. G.

1993-04-01

238

Momentum spectra of electrons rescattered from rare-gas targets following their extraction by one- and two-color femtosecond laser pulses  

NASA Astrophysics Data System (ADS)

We have used velocity-map imaging to measure the three-dimensional momenta of electrons rescattered from Xe and Ar following the liberation of the electrons from these atoms by 45 fs, 800 nm intense laser pulses. Strong structure in the rescattering region is observed in both angle and energy, and is interpreted in terms of quantitative rescattering (QRS) theory. Momentum images have also been taken with two-color (800 nm + 400 nm) pulses on Xe targets. A strong dependence of the spectra on the relative phase of the two colors is observed in the rescattering region. Interpretation of the phase dependence using both QRS theory and a full solution to the time-dependent Schrödinger equation shows that the rescattered electrons provide a much more robust method for determining the relative phase of the two colors than do the direct electrons.

Ray, D.; Chen, Zhangjin; de, S.; Cao, W.; Litvinyuk, I. V.; Le, A. T.; Lin, C. D.; Kling, M. F.; Cocke, C. L.

2011-01-01

239

Optimal design of thermally coupled distillation columns  

Microsoft Academic Search

This paper considers the optimal design of thermally coupled distillation columns and dividing wall columns using detailed column models and mathematical optimization. The column model used is capable of describing both conventional and thermally coupled columns, which allows comparisons of different structural alternatives to be made. Possible savings in both operating and capital costs of up to 30% are illustrated

G. Duennebier; Constantinos C. Pantelides

1999-01-01

240

Modeling seismic stimulation: Enhanced non-aqueous fluid extraction from saturated porous media under pore-pressure pulsing at low frequencies  

Microsoft Academic Search

Seismic stimulation, the application of low-frequency stress-pulsing to the boundary of a porous medium containing water and a non-aqueous fluid to enhance the removal of the latter, shows great promise for both contaminated groundwater remediation and enhanced oil recovery, but theory to elucidate the underlying mechanisms lag significantly behind the progress achieved in experimental research. We address this conceptual lacuna

Wei-Cheng Lo; Garrison Sposito; Yu-Han Huang

241

Extracting the distribution of laser damage precursors on fused silica surfaces for 351 nm, 3 ns laser pulses at high fluences (20-150 J/cm2).  

PubMed

Surface laser damage limits the lifetime of optics for systems guiding high fluence pulses, particularly damage in silica optics used for inertial confinement fusion-class lasers (nanosecond-scale high energy pulses at 355 nm/3.5 eV). The density of damage precursors at low fluence has been measured using large beams (1-3 cm); higher fluences cannot be measured easily since the high density of resulting damage initiation sites results in clustering. We developed automated experiments and analysis that allow us to damage test thousands of sites with small beams (10-30 µm), and automatically image the test sites to determine if laser damage occurred. We developed an analysis method that provides a rigorous connection between these small beam damage test results of damage probability versus laser pulse energy and the large beam damage results of damage precursor densities versus fluence. We find that for uncoated and coated fused silica samples, the distribution of precursors nearly flattens at very high fluences, up to 150 J/cm2, providing important constraints on the physical distribution and nature of these precursors. PMID:22565775

Laurence, Ted A; Bude, Jeff D; Ly, Sonny; Shen, Nan; Feit, Michael D

2012-05-01

242

Fiber Composite Columns under Compression.  

National Technical Information Service (NTIS)

The micromechanics of fiber composite columns under compression is investigated theoretically. The model is based on the assumption that the fiber buckles inside the matrix under critical load. In the postbuckling range the fiber is considered as a beam o...

Y. C. B. Fung Y. N. Lanir

1971-01-01

243

Finite Element Beam Column Analysis.  

National Technical Information Service (NTIS)

A beam column under compressive loads with initial curvature exhibits typically different behavior as compared to linear elastic response of structural members within the framework of small displacement theory. For rings and beams with small initial curva...

J. H. Vandersloot

1977-01-01

244

Preconcentration and separation of copper, nickel and zinc in aqueous samples by flame atomic absorption spectrometry after column solid-phase extraction onto MWCNTs impregnated with D2EHPA-TOPO mixture.  

PubMed

A solid phase extraction method has been developed for the determination of copper, nickel and zinc ions in natural water samples. This method is based on the adsorption of copper, nickel and zinc on multiwalled carbon nanotubes (MWCNTs) impregnated with di-(2-ethyl hexyl phosphoric acid) (D2EHPA) and tri-n-octyl phosphine oxide (TOPO). The influence of parameters such as pH of the aqueous solution, amount of adsorbent, flow rates of the sample and eluent, matrix effects and D2EHPA-TOPO concentration have been investigated. Desorption studies have been carried out with 2 mol L(-1) HNO(3). The copper, nickel and zinc concentrations were determined by flame atomic absorption spectrometry. The results indicated that the maximum adsorption of copper, nickel and zinc is at pH 5.0 with 500 mg of MWCNTs. The detection limits by three sigma were 50 ?g L(-1) for copper, 40 ?g L(-1) for nickel and 60 ?g L(-1) zinc. The highest enrichment factors were found to be 25. The adsorption capacity of MWCNTs-D2EHPA-TOPO was found to be 4.90 mg g(-1) for copper, 4.78 mg g(-1) for nickel and 4.82 mg g(-1) for zinc. The developed method was applied for the determination of copper, nickel and zinc in electroplating wastewater and real water sample with satisfactory results (R.S.D.'s <10%). PMID:21041024

Vellaichamy, S; Palanivelu, K

2011-01-30

245

Computer simulation of non-neutral plasma column  

Microsoft Academic Search

This dissertation studies wave propagation in a non- neutral plasma column by comparing theoretical predictions with the results of two-dimensional electrostatic particle-in-cell simulation codes. Linear and nonlinear pulses propagating parallel to the confining magnetic field are created in a slab model simulation (Ramachandran et al. Phys. Fluids B 5, 2733 (1993)) through the application of negative potentials to segments of

Scott Christopher Neu

1997-01-01

246

Telescoping columns. [parabolic antenna support  

NASA Technical Reports Server (NTRS)

An extendable column is described which consists of several axially elongated rigid structural sections nested within one another. Each section includes a number of rotatably attached screws running along its length. The next inner section includes threaded lugs oriented to threadingly engage the screws. The column is extended or retracted upon rotation of the screws. The screws of each section are selectively rotated by a motor and an engagement mechanism.

Mazur, J. T. (inventor)

1980-01-01

247

Characterization of low-molecular-weight metal species in plant extracts by using HPLC with pulsed amperometric detection and cyclic voltammetry  

Microsoft Academic Search

An analytical separation scheme is presented for the isolation of low-molecular-weight metal species (< 10 kDa) in plants.\\u000a After ultrafiltration of the aqueous plant extracts isotachophoresis or gel chromatography is used for pre-separation and\\u000a HPLC at a cyclodextrin-phase for further separation of metal containing fractions. Trace metals are detected off-line by using\\u000a either adsorptive stripping voltammetry for platinum or AAS

G. Weber; F. Alt; J. Messerschmidt

1998-01-01

248

Pulse transformers  

Microsoft Academic Search

Pulse transformers capable of transmitting substantially rectangular voltage pulses, with durations of less than one microsecond, were developed for radar applications during World War II. Their primary functions were to match the impedances of high-power microwave radio-frequency electron-tube generators to electronic pulse generators and coaxial transmission cables, and to provide polarity reversal and impedance matching functions within pulse generator circuitry.

H. Lord

1971-01-01

249

Maximizing efficiency using Agilent Poroshell 120 columns  

Microsoft Academic Search

Columns based on superficially porous technologies are an alternative to sub-2-µm particle based columns. The combination of these columns with the Agilent 1290 Infinity LC system produces high efficiency separations. Agilent Poroshell 120 columns offer:  Lower back pressure  Highest efficiency  Comparable volume capacity Author

Angelika Gratzfeld-Hüsgen; Edgar Naegele

250

Effects of Column Conditions on the First-Order Rate Modeling of Nonequilibrium Solute Breakthrough  

Microsoft Academic Search

First-order mass transfer models are commonly used as a means of interpreting sorption-related mass transfer in laboratory columns, often with the intent of approximating diffusion-based processes. We have fitted first-order model parameters to computer-simulated breakthrough curves from hypothetical column experiments in which Fickian diffusion into spherical particles limited the rate of sorption and desorption. Using both step and pulse inputs,

Dirk F. Young; William P. Ball

1995-01-01

251

Adsorption and transport of cadmium and rhodamine WT in pumice sand columns  

Microsoft Academic Search

The transport and attenuation of cadmium (Cd) and rhodamine WT (RWT) in a pumice sand aquifer media was investigated using column experiments to study a scenario of point?source contamination. A pore?water velocity of 1.7–1.8 m\\/day, which is a typical field groundwater velocity in a pumice sand aquifer system, was applied to triplicate columns. A pulse of a solution containing Cd

Liping Pang; Murray Close; Helen Greenfield; Greg Stanton

2004-01-01

252

Effects of column conditions on the first-order rate modeling of nonequilibrium solute breakthrough  

Microsoft Academic Search

First-order mass transfer models are commonly used as a means of interpreting sorption-related mass transfer in laboratory columns, often with the intent of approximating diffusion-based processes. We have fitted first-order model parameters to computer-simulated breakthrough curves from hypothetical column experiments in which Fickian diffusion into spherical particles limited the rate of sorption and desorption. Using both step and pulse inputs,

Dirk F. Young; William P. Ball

1995-01-01

253

Editorial: Research and Teaching Column  

NSDL National Science Digital Library

The JCST Research and Teaching column will feature sound research on curriculum, pedagogy, and student learning at the college level. Topics of interest include all fields of science: chemistry, biology, geology, astronomy, physics, geography, mathematics, environmental science, and computer science. Studies that are interdisciplinary or are readily applicable to several disciplines in the sciences are also of interest.

Towns, Marcy

2008-03-01

254

Fluid Dynamic Experiments on Mush Column Magmatism  

NASA Astrophysics Data System (ADS)

A vertically extensive stack of sills interconnected by pipe-like conduits extending from the mantle through the lithosphere and capped by a volcanic center is a magmatic mush column. At any instant at various locations it contains fractionated and primitive melts as pools of nearly crystal-free magma, pools of crystal-rich magma, thick beds of cumulates, open conduits, and conduits congested by cognate and wall debris. All boundaries of the system are sheathed by solidification fronts. With the wide range of local, characteristic length scales there is a commensurate range of solidification time scales. This creates a complicated series of resistances to magma flow and provides a variety of distinct local physical environments for the chemical modification of magma. The system is driven by over-pressure from the addition of new melt from below. The over-pressure propagates upward by moving magma which flushes conduits, disrupts cumulate beds, and pools or purges sills. A critical aspect of this process is the entrainment, transport, and deposition of crystals throughout the system. Picritic lavas charges with entrained (tramp) olivine of a wide compositional range erupted at many systems (e.g. Jan Mayen, Kilauea, Reunion, etc.) are the final expression of this process. That the size and abundance of these crystals is correlated with eruptive flux (Murata & Richter, AJS, 1966) suggests an important indicator of the overall dynamics of the mush column. A mush column of this basic nature is observed is observed in the McMurdo Dry Valleys region of Antarctica and is inferred beneath Hawaii and the ocean ridges. We have attempted to model this process by studying the entrainment, transport, and deposition of particles in a vertical stack of sills (Plexiglas tanks) connected by resistive conduits (check valves), over-pressured from the base, and open at the top. The system is about two meters in height with water and oil as fluids and particles with Reynolds numbers that closely approximate actual crystals. Particles of a range of sizes are placed in the lower input pipe and carried by the fluid. The base state is a sustained over-pressure that permits a steady effusive flux throughout the system. To establish this state, the conduit resistance (check valve tension) must be overcome. As the critical moment of flow is approached, the system exudes a high-pitched vibration emanating from the check valves which may be akin to the well-known harmonic tremor of active volcanic systems. We also employ a time-series of over-pressure pulses, designed to mimic eruptive episodes of volcanism as estimated by Simkin (An. Rev. EPS, 1993). We observe many aspects of the process described above: particle deposition on sill floors forming beds around the conduits, cumulate piles disrupted by flux associated with over-pressure pulses, and flushing of choked conduits. The largest particle concentrations are in the basal sill and particle concentration decreases upward in the system. The magnitude and frequency of over-pressure pulses controls the ability of the system to erupt particles. Cumulate deposition is restricted to the conduit areas in each sill unless the flow is made to spread throughout the sill by horizontally separating the inflow and outflow conduits. Spreading flows, which form laterally graded cumulates, are also achieved by simulating outward lateral propagation of the sill via side-wall taps. The overall dynamic behavior of the system as understood so far suggests that the time history of the cumulate eruptive flux, as measured by crystal size, abundance, and composition, may carry enough information to critically evaluate the deep plumbing and dynamics of many magmatic-volcanic systems.

Flanagan-Brown, R. E.; Marsh, B. D.

2001-05-01

255

Column  

ERIC Educational Resources Information Center

Summarizes some activities concerning chemistry education, including a brief report of the 1973 conference on teaching of pre-university courses, a statement about using plastics containers, a survey of mathematical skills in chemistry, discussions about the Nuffield Foundation 27th Report and the report "Science for the 13-16 Age Group." (CC)

Education in Chemistry, 1974

1974-01-01

256

Column  

ERIC Educational Resources Information Center

Articles are included concerning industry and schools, science and mathematics award scheme, teaching and research, safety, inservice training, Ugandan chemistry, plastics, and 19th century Nuffield. (DF)

Education in Chemistry, 1973

1973-01-01

257

Revised Thermal Analysis of LANL Ion Exchange Column  

SciTech Connect

This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column.1 LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solutions. The Defense Nuclear Facilities Safety Board has requested an updated analysis to calculate maximum temperatures for higher resin loading capacities obtained with a new formulation of the Reillex HPQ anion exchange resin. The increased resin loading capacity will not exceed 118 g plutonium per L of resin bed. Calculations were requested for normal operation of the resin bed at the minimum allowable solution feed rate of 30 mL/min and after an interruption of flow at the end of the feed stage, when one of the columns is fully loaded. The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades. At low temperatures, resin bed temperatures increase primarily due to decay heat. At {approx}70 C a Low Temperature Exotherm (LTE) resulting from the reaction between 8-12 M HNO{sub 3} and the resin has been observed. The LTE has been attributed to an irreversible oxidation of pendant ethyl benzene groups at the termini of the resin polymer chains by nitric acid. The ethyl benzene groups are converted to benzoic acid moities. The resin can be treated to permanently remove the LTE by heating a resin suspension in 8M HNO{sub 3} for 30-45 minutes. No degradation of the resin performance is observed after the LTE removal treatment. In fact, heating the resin in boiling ({approx}115-120 C) 12 M HNO{sub 3} for 3 hr displays thermal stability analogous to resin that has been treated to remove the LTE. The analysis is based on a previous study of the SRS Frames Waste Recovery (FWR) column, performed in support of the Pu-238 production campaign for NASA's Cassini mission. In that study, temperature transients following an interruption of flow to the column were calculated. The transient calculations were terminated after the maximum resin bed temperature reached the Technical Standard of 60 C, which was set to prevent significant resin degradation. The LANL column differs from the FWR column in that it has a significantly smaller radius, 3.73 cm nominal versus approximately 28 cm. It follows that natural convection removes heat much more effectively from the LANL column, so that the column may reach thermal equilibrium. Consequently, the calculations for a flow interruption were extended until an approach to thermal equilibrium was observed. The LANL ion exchange process also uses a different resin than was used in the FWR column. The LANL column uses Reillex HPQ{trademark} resin, which is more resistant to attack by nitric acid than the Ionac 641{trademark} resin used in the FWR column. Heat generation from the resin oxidation reaction with nitric acid is neglected in this analysis since LANL will be treating the resin to remove the LTE prior to loading the resin in the columns. Calculations were performed using a finite difference computer code, which incorporates models for absorption and elution of plutonium and for forced and natural convection within the resin bed. Calculations for normal column operation during loading were performed using an initial temperature and a feed temperature equal to the ambient air temperature. The model for the normal flow calculations did not include natural convection within the resin bed. The no flow calculations were started with the temperature and concentration profiles at the end of the loading stage, when there would be a maximum amount of plutonium either adsorbed on the resin or in the feed solution in the column.

Laurinat, J

2006-04-11

258

Evaluation of fluoride-induced metal mobilization in soil columns  

SciTech Connect

Fluoride in soil solution may cause substantially increased leaching of dissolved organic carbon (DOC), Al, and heavy metals from soils. The authors objective was to examine whether increased metal solubility is attributable to formation of fluoro- or organo-complexes. The A horizon of a Slovak soil contaminated with heavy metals and F by Al smelter emissions was used to conduct two column experiments under saturated and steady-state water flow conditions. The columns were leached with 5 mM Na{sub 2}SO{sub 4}, 1 mM NaCl, and 9 mM NaF solutions at pH 5.5 and an electrical conductivity of 1,000 {micro}S cm{sup {minus}1}. Samples were collected in 70-min intervals for approximately 7 d. Two experiments were performed. In the first experiment (single F pulse), a fluoride (F) pulse was applied for 36 pore volumes (PVs), while in the second experiment (dual F pulse), two consecutive F pulses (each for 2.8 PVs) were applied. For both experiments, Cl breakthrough curves (BTCs) revealed a convection-dominated transport regime. The breakthrough of Cd, Cr, Fe, Ni, and Pb paralleled DOC breakthrough in both experiments indicating metal leaching as organocomplex. In the dual F pulse experiment, peak separation of the DOC and the complexed F (F{sub bound}) breakthrough was achieved. The highest F{sub bound} concentration occurred 3.8 PVs later than that of DOC. The AlBTC paralleled that of F{sub bound} but showed tailing with a turning point simultaneous to the highest DOC concentration. Thus, the increase in Al solubility was mainly caused by fluoro-complexation and only to a lesser extent by organo-complexation.

Totsche, K.U.; Wilcke, W.; Koerber, M.; Kobza, J.; Zech, W.

2000-04-01

259

Density Column Lab - Part 1  

NSDL National Science Digital Library

In this first part of a two-part lab activity, students use triple balance beams and graduated cylinders to take measurements and calculate the densities of several common, irregularly shaped objects with the purpose to resolve confusion about mass and density. After this activity, conduct the associated Density Column Lab - Part 2 activity before presenting the associated Density & Miscibility lesson for discussion about concepts that explain what students have observed.

GK-12 Program,

260

Novel electrostatic column for ion projection lithography  

SciTech Connect

Ion projection lithography (IPL) is being considered for high volume sub-0.25-[mu]m lithography. A novel ion-optical column has been designed for exposing 20[times]20 mm[sup 2] fields at 3[times] reduction from stencil mask to wafer substrates. A diverging lens is realized by using the stencil mask as the first electrode of the ion-optical column. The second and third electrode form an accelerating field lens. The aberrations of the first two lenses (diverging lens and field lens) are compensated by an asymmetric Einzel lens projecting an ion image of the stencil mask openings onto the wafer substrate with better than 2 mrad telecentricity. Less than 30 nm intrafield distortion was calculated within 20[times]20 mm[sup 2] exposure fields. The calculation uncertainty is estimated to be about 10 nm. The calculation holds for helium ions with [approx]10 keV ion energy at the stencil mask and 150 keV ion energy at the wafer plane. A virtual ion source size of 10 [mu]m has been assumed. The calculated chromatic aberrations are less than 60 nm, assuming 6 eV energy spread of the ions extracted from a duoplasmatron source. Recently a multicusp ion source has been developed for which preliminary results indicate an energy spread of less than 2 eV. Thus, with a multicusp source chromatic aberrations of less than 20 nm are to be expected. The ion energy at the crossover between the field lens and the asymmetric Einzel lens is 200 keV. Therefore, stochastic space charge induced degradations in resolution can be kept sufficiently low. The divergence of the ion image projected to the wafer plane is less than 2 mrad. Thus, the usable'' depth of focus for the novel ion optics is in the order of 10 [mu]m.

Chalupka, A.; Stengl, G.; Buschbeck, H.; Lammer, G.; Vonach, H.; Fischer, R.; Hammel, E.; Loeschner, H.; Nowak, R.; Wolf, P. (IMS - Ion Microfabrication Systems GmbH, A-1020 Vienna (Austria)); Finkelstein, W.; Hill, R.W. (Advanced Lithography Group, Columbia, Maryland 21045 (United States)); Berry, I.L. (Department of Defense, Microelectronics Research Laboratory, Columbia, Maryland 21045 (United States)); Harriott, L.R. (AT T Bell Laboratories, Murray Hill, New Jersey 07974 (United States)); Melngailis, J. (University of Maryland, College Park, Maryland 20742 (United States)); Randall, J.N. (Texas Instruments, Dallas, Texas 75243 (United States)); Wolfe, J.C. (University of Houston, Houston, Texas 77204 (United States)); Stroh, H.; Wollnik, H. (University of Giessen, D-35392 Giessen (Germany)); Mondelli, A.A.; Petillo, J.J. (Science Applications International Corporation, McLean, Virginia 22102 (United States)); Leung, K. (Lawrence Berkeley Laboratory, University of Californi

1994-11-01

261

[Design and implementation of pulse instrument based on DSP].  

PubMed

The Traditional Chinese Medical Pulse Instrument uses the HKG-07B infrared pulse sensor to get pulse signal from the body. It makes full use of the TMS320VC5402 chip to realize time-frequency domain parameters extracting, classification and identification of the pulse signal. The system can store a plenty of pulse signal and realize data communication with the PC via the USB interface. According to acquisition and classification of pulse signal experiments of 200 subjects, the results show that the recognition rate of pulse signal can reach to 87.4%. It is applicable to the clinical diagnosis and detection of the pulse signal and home healthcare. PMID:23777066

Jiao, Qiyu; Pang, Chunying

2013-03-01

262

Method for packed column separations and purifications  

DOEpatents

The invention encompasses a method of packing and unpacking a column chamber. A mixture of a fluid and a matrix material are introduced through a column chamber inlet so that the matrix material is packed within a column chamber to form a packed column. The column chamber having the column chamber inlet or first port for receiving the mixture further has an outlet port and an actuator port. The outlet port is partially closed for capturing the matrix material and permitting the fluid to flow therepast by rotating relative one to the other of a rod placed in the actuator port. Further rotation relative one to the other of the rod and the column chamber opens the outlet and permits the matrix material and the fluid to flow therethrough thereby unpacking the matrix material from the column chamber.

Holman, David A. (Richland, WA); Bruckner-Lea, Cynthia J. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Chandler, Darrell P. (Richland, WA)

2006-08-15

263

The Shape of the Tallest Column  

Microsoft Academic Search

. The height at which an unloaded column will buckle under its own weight is thefourth root of the least eigenvalue of a certain Sturm--Liouville operator. We show that the operatorassociated with the column proposed by Keller and Niordson (The Tallest Column, J. Math. Mech.,16 (1966), pp. 433--446) does not possess a discrete spectrum. This calls into question their formaluse

C. Maeve Mccarthy; Steven J. Cox

1998-01-01

264

Stratigraphic Columns Across Southern Western Interior  

NSDL National Science Digital Library

This website depicts stratigraphic columns of exposed rocks in southwestern regions of the United States. A general explanation of symbols used in the columns is provided for reference, and the columns indicate rock type, formation names and geologic time periods. The areas covered include the Grand Canyon, central and southern Arizona, southern Utah and Nevada, and western New Mexico and Colorado.

Blakey, Ronald

265

29 CFR 1926.755 - Column anchorage.  

Code of Federal Regulations, 2013 CFR

...the top of the column shaft. (3) Columns shall be set on level finished floors, pre-grouted leveling plates, leveling nuts, or shim packs which are adequate to transfer the construction loads. (4) All columns shall be evaluated by a...

2013-07-01

266

How to design baffle tray columns  

Microsoft Academic Search

As with packed columns, well-known heat transfer equations can be used to estimate mass transfer efficiencies for baffle tray columns. Other variables that can be calculated using this method include: flooding capacity, pressure drop, number of transfer units (NTUs) and the height equivalent to a theoretical plate (HETP). Gas-liquid contacting columns containing simple baffles have been used in hydrocarbon processing

Fair

1993-01-01

267

MICROSTRUCTURAL PROPERTIES OF COLUMN CONSOLIDATED PASTE BACKFILL  

Microsoft Academic Search

The objective of this study is to characterize the microstructural properties of cemented paste backfill (CPB) after its self-weight consolidation in columns. To reach this objective, three self-weight consolidation column tests that have each 3 m height were carried out on in situ CPB samples at Louvicourt mine's backfill plant. These columns simulate three realistic drainage scenarios such as fully

Erol Yilmaz

268

Method for liquid chromatographic extraction of strontium from acid solutions  

DOEpatents

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

Horwitz, E. Philip (Naperville, IL); Dietz, Mark L. (Evanston, IL)

1992-01-01

269

Influence of biodegradation on carbazole and benzocarbazole distributions in oil columns from the Liaohe basin, NE China  

Microsoft Academic Search

Alkylcarbazoles and benzocarbazoles in petroleum reservoir core extracts isolated from several oil columns within the Lengdong oilfield, Liaohe basin, China were studied to investigate their occurrence and the effect of biodegradation on their concentrations and distributions. Bulk petroleum composition and molecular data indicate the occurrence of systematic biodegradation gradients within the oil columns, the extent of biodegradation ranging from light

Haiping Huang; Bernard F. J. Bowler; Zhanwen Zhang; Thomas B. P. Oldenburg; Steve R. Larter

2003-01-01

270

Dry-Column Flash Chromatography  

NASA Astrophysics Data System (ADS)

Dry-column flash chromatography is a safe, powerful, yet easily learned preparative chromatography technique. It has proven useful in research, and an adaptation of the technique for use in large teaching laboratories (general chemistry, organic chemistry) is described here. The student version is similar to vacuum filtration, uses the same compact, readily available glassware, and inexpensive and safe solvents (ethyl acetate and hexane) and adsorbent (Merck grade 60 silica gel). The technique is sufficiently simple and powerful that a beginning student can successfully resolve diastereomers on sample scales ranging from 100 mg to >1 g.

Shusterman, Alan J.; McDougal, Patrick G.; Glasfeld, Arthur

1997-10-01

271

Gravitational light bending near neutron stars. I - Emission from columns and hot spots  

Microsoft Academic Search

The beam shapes, pulse profiles, and spectral transmission function at infinity for the radiation originating in columns or hot spots on slowly rotating neutron stars, represented by the Schwarzschild metric, are calculated. These are used for models for binary accreting pulsars and may apply to isolated neutron stars as well. The shadowing effects and their interplay with the frequency changes

H. Riffert; P. Meszaros

1988-01-01

272

Soil microbial growth and biofilm expansion assessment under wastewater infiltration percolation treatment process: column experiments  

Microsoft Academic Search

The current work tackles the problem of soil microbial growth and biofilm expansion assessment in infiltration percolation process in order to optimize the technique design and monitoring. Experiments were conducted on a sand filled PVC column fed at a pulsed rhythm of 8 sequences per day in order to maximize the soil aeration that generates a better oxygen renewal in

Asma Ben Rajeb; Hamadi Kallali; Nadhira Ben Aissa; Olfa Bouzaiene; Salah Jellali; Naceur Jedidi; Abdennaceur Hassen

2009-01-01

273

Preparation and application of organic-silica hybrid monolithic capillary columns.  

PubMed

Organic-silica hybrid monolithic columns have drawn more and more attention due to the ease of preparation and good mechanical stability in recent years. Many synthetic approaches have been developed and a variety of hybrid monolithic capillary columns have been prepared. The sol-gel process is well recognized in the fabrication of hybrid monolithic columns, which can be mainly classified as one-step, acid/base two-step procedures. The new approaches such as the "one-pot" and nano-scaled inorganic-organic hybrid reagent of polyhedral oligomeric silsesquioxane used as a cross-linker have also emerged for the preparation of hybrid monolithic columns. The applications of the organic-silica hybrid monolithic capillary columns for capillary electrochromatography, micro high-performance liquid chromatography, solid-phase micro-extraction and enzymatic reactor etc. are included in this review. PMID:21171117

Wu, Minghuo; Wu, Ren'an; Zhang, Zhenbin; Zou, Hanfa

2011-01-01

274

EVALUATION OF FEMA 356 MODELS FOR REINFORCED CONCRETE COLUMNS AND BEAM-COLUMN JOINTS  

Microsoft Academic Search

This study investigates the accuracy of FEMA 356 shear and flexure modeling procedures for reinforced concrete (RC) columns and beam-column joints with poorly detailed or insufficient reinforcement. Following the FEMA 356 guidelines, generalized flexure and shear force- deformation relations were developed and compared with the experimental data from 26 column specimens and 17 beam-column joint specimens. Specifically, the measured and

H. Sezen; F. Alemdar

275

Winogradsky Column Unit: Chemical and Physical Change  

NSDL National Science Digital Library

This two-part activity leads Physical Science students, grades 8-12, to explore chemical change using Winogradsky Columns. Part 1 constructs student concepts concerning chemical and physical changes. Part 2 asks students to compare physical versus chemical changes and observe chemical changes in a Winogradsky Column, and teaches them to build their own column. It includes the following student pages: introductory lesson, Winogradsky Column lesson, challenge your thinking activity sheet, how to make a Winogradsky Column, how to create an observation journal, and journal evaluation sheet.

Pevzner, Yevgeny; Shelton, Sharyn A.; Project, Westminster C.

276

Pulse Data.  

ERIC Educational Resources Information Center

Presents an activity using computer software to investigate the role of the heart and blood, how the blood system responds to exercise, and how pulse rate is a good measure of physical condition. (ASK)

Hands On!, 1998

1998-01-01

277

Pulse stretcher  

DOEpatents

Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

Horton, James A. (Livermore, CA) [Livermore, CA

1994-01-01

278

Properties of monolithic silica columns for HPLC.  

PubMed

Monolithic silica columns and their use in high peak-capacity HPLC separations are reviewed. Monolithic silica columns can potentially provide higher overall performance than particle-packed columns based on the variable external porosity and variable through-pore size/skeleton size ratios. The high permeability of monolithic silica columns resulting from the high porosity is shown to be advantageous to generate large numbers of theoretical plates with long capillary columns. High permeability together with the high stability of the network structures of silica allows their use in high-speed separations required for a second-dimension column in two dimensional HPLC. Disadvantages of monolithic silica columns are also described. PMID:16760589

Kobayashi, Hiroshi; Ikegami, Tohru; Kimura, Hiroshi; Hara, Takeshi; Tokuda, Daisuke; Tanaka, Nobuo

2006-04-01

279

Soil column leaching of pesticides.  

PubMed

In this review, I address the practical and theoretical aspects of pesticide soil mobility.I also address the methods used to measure mobility, and the factors that influence it, and I summarize the data that have been published on the column leaching of pesticides.Pesticides that enter the unsaturated soil profile are transported downwards by the water flux, and are adsorbed, desorbed, and/or degraded as they pass through the soil. The rate of passage of a pesticide through the soil depends on the properties of the pesticide, the properties of the soil and the prevailing environmental conditions.Because large amounts of many different pesticides are used around the world, they and their degradates may sometimes contaminate groundwater at unacceptable levels.It is for this reason that assessing the transport behavior and soil mobility of pesticides before they are sold into commerce is important and is one indispensable element that regulators use to assess probable pesticide safety. Both elementary soil column leaching and sophisticated outdoor lysimeter studies are performed to measure the leaching potential for pesticides; the latter approach more reliably reflects probable field behavior, but the former is useful to initially profile a pesticide for soil mobility potential.Soil is physically heterogeneous. The structure of soil varies both vertically and laterally, and this variability affects the complex flow of water through the soil profile, making it difficult to predict with accuracy. In addition, macropores exist in soils and further add to the complexity of how water flow occurs. The degree to which soil is tilled, the density of vegetation on the surface, and the type and amounts of organic soil amendments that are added to soil further affect the movement rate of water through soil, the character of soil adsorption sites and the microbial populations that exist in the soil. Parameters that most influence the rate of pesticide mobility in soil are persistence (DT50) of the pesticide, and its sorption/desorption(Koc) characteristics. These parameters may vary for the same pesticide from geographic site-to-site and with soil depth. The interactions that normally occur between pesticides and dissolved organic matter (DOM) or WDC are yet other factors that may complicate pesticide leaching behavior.The soil mobility of pesticides is normally tested both in the laboratory and in the field. Lab studies are initially performed to give researchers a preliminary appraisal of the relative mobility of a pesticide. Later, field lysimeter studies can be performed to provide more natural leaching conditions that emulate the actual field use pattern. Lysimeter studies give the most reliable information on the leaching behavior of a pesticide under field conditions, but these studies are time-consuming and expensive and cannot be performed everywhere. It is for this reason that the laboratory soil column leaching approach is commonly utilized to profile the mobility of a pesticide,and appraise how it behaves in different soils, and relative to other pesticides.Because the soil structure is chemically and physically heterogenous, different pesticide tests may produce variable DT50 and Koc values; therefore, initial pesticide mobility testing is undertaken in homogeneously packed columns that contain two or more soils and are eluted at constant flow rates. Such studies are done in duplicate and utilize a conservative tracer element. By fitting an appropriate mathematical model to the breakthrough curve of the conservative tracer selected,researchers determine key mobility parameters, such as pore water velocity, the column-specific dispersion coefficient, and the contribution of non equilibrium transport processes. Such parameters form the basis for estimating the probable transport and degradation rates that will be characteristic of the tested pesticide. Researchers also examine how a pesticide interacts with soil DOM and WDC, and what contribution from facilitated transport to mobility is made as a result of the effects of

Katagi, Toshiyuki

2013-01-01

280

Purification of polar compounds from Radix isatidis using conventional C18 column coupled with polar-copolymerized C18 column.  

PubMed

Regarding hydrophilic interaction chromatography and normal phase liquid chromatography, RPLC is another choice used to separate polar compounds with the improvement of polar-modified C18 stationary phase. In this study, a method using conventional C18 column coupled with polar-copolymerized C18 column was successfully developed for the separation and purification of polar compounds from Radix isatidis, which is one of the most commonly used traditional Chinese medicines (TCMs). An XTerra MS C18 column was used to fractionate the extract of R. isatidis and a homemade polar-copolymerized C18 column was utilized for the final purification due to its good separation selectivity and high resolution for polar compounds. The established purification system demonstrated good orthogonality for the polar compounds. As a result, ten compounds were purified and three of them were identified as 3-methyl-5-vinyloxazolidin-2-one (compound A), 5-hydroxymethyl-2-furaldehyde (compound B) and 3-methylfuran-2-carboxylic acid (compound G) based on the MS, IR and extensive NMR data, respectively. It was demonstrated to be a feasible and powerful technique for the purification of polar compounds under RPLC mode and more chemical information of TCMs will be obtained to interpret the efficiency of TCMs. PMID:20886519

Zeng, Jing; Guo, Zhimou; Xiao, Yuansheng; Wang, Chaoran; Zhang, Xiuli; Liang, Xinmiao

2010-11-01

281

Propagation of axisymmetric Trivelpiece-Gould mode along vortex columns generated by diocotron instability  

SciTech Connect

A high-frequency (HF) oscillation has been observed to propagate along magnetic field lines with an axisymmetric profile extending over multiple columns of magnetized pure electron plasma which undergo two-dimensional vortex motions. The observed frequency is a few hundred times higher than the rotation frequency of the vortices and varies in time as the density distribution of electrons deforms from an unstable hollow profile into vortex columns and approaches a single-peaked distribution. Experimental examinations reveal that the HF oscillation is excited by the gate pulse applied to prepare the initial profile and that the oscillation does not influence the subsequent dynamics of vortex columns. Further examinations including detailed observations and theoretical analyses indicate that the HF oscillation represents a profile-dependent eigenfunction of the Trivelpiece-Gould mode wave that consists of a dominant axisymmetric component and small fractions of higher azimuthal modes associated with the density distribution separated into columns.

Kawai, Y.; Kiwamoto, Y.; Soga, Y.; Aoki, J. [Graduate School of Human and Environmental Studies, Kyoto University, Yoshidanihonmatsu-cho-Kyoto-shi, Kyoto-fu 606-8501 (Japan)

2007-10-15

282

Tevatron extraction microcomputer  

NASA Astrophysics Data System (ADS)

Extraction in the fErmilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad extraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the bucker and pulse magnets at a rate of 5760 Hz, and the QXR magnets at 720 Hz. QXR supports multiple slow spills (up to a total of 35 seconds) with multiple fast pulses intermixed. It linearizes the slow spill and bucks out the high frequency components. Fast extraction is done by outputting a variable pulse waveform. Closed loop learning techniques are used to improve performance from cycle to cycle for both slow and fast extraction. The system is connected to the Tevatron clock system so that it can track the machine cycle. QXR is also connected to the rest of the Fermilab control system, ACNET. Through ACNET, human operators and central computers can monitor and control extraction through communications with QXR. The controls hardware and software both employ some standard and some specialized components. This paper gives an overview of QXR as a control system; another paper summarizes performance.

Chapman, L.; Finley, D. A.; Harrison, M.; Merz, W.

1985-06-01

283

Tevatron extraction microcomputer  

SciTech Connect

Extraction in the Fermilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad eXtraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the ''bucker'' and ''pulse'' magnets at a rate of 5760 Hz, and the ''QXR'' magnets at 720 Hz. QXR supports multiple slow spills (up to a total of 35 seconds) with multiple fast pulses intermixed. It linearizes the slow spill and bucks out the high frequency components. Fast extraction is done by outputting a variable pulse waveform. Closed loop learning techniques are used to improve performance from cycle to cycle for both slow and fast extraction. The system is connected to the Tevatron clock system so that it can track the machine cycle. QXR is also connected to the rest of the Fermilab control system, ACNET. Through ACNET, human operators and central computers can monitor and control extraction through communications with QXR. The controls hardware and software both employ some standard and some specialized components. This paper gives an overview of QXR as a control system; another paper summarizes performance.

Chapman, L.; Finley, D.A.; Harrison, M.; Merz, W.

1985-06-01

284

Results of Beam Extraction Performance for the KSTAR Neutral Beam Injector  

NASA Astrophysics Data System (ADS)

The first neutral beam injector (NBI-1) has been developed for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. The first long pulse ion source (LPIS-1) has been installed on the NBI-1 for an auxiliary heating and current drive of KSTAR plasmas. The performance of ion and neutral beam extractions in the LPIS-1 was investigated initially on the KSTAR NBI-1 system, prior to the neutral beam injection into the main plasmas. The ion source consists of a magnetic bucket plasma generator with multipole cusp fields and a set of prototype tetrode accelerators with circular apertures. The inner volume of the plasma generator and accelerator column in the LPIS-1 is approximately 123 L. Design requirements for the ion source were a 120 kV/65 A deuterium beam and a 300 s pulse length. The extraction of ion beams was initiated by the formation of arc plasmas in the LPIS-1, called the arc-beam extraction method. A stable ion beam extraction of the LPIS-1 was achieved up to 85 kV/32 A for a 5 s pulse length and 80 kV/25 A for a 14 s pulse length. An optimum beam perveance of 1.15 ?perv was observed at an acceleration voltage of 60 kV. Neutralization efficiency was measured by a water-flow calorimetry (WFC) method using a calorimeter and the operation of a bending magnet. The full-energy species of ion beams were detected by using the diagnostic method of optical multichannel analyzer (OMA). An arc efficiency of the LPIS was 0.6--1.1 A/kW depending on the operating conditions of arc discharge. A neutral beam power of ˜1.0 MW must be sufficiently injected into the KSTAR plasmas from the LPIS-1 at a beam energy of 80 keV.

Chang, Doo-Hee; Jeong, Seung Ho; Kim, Tae-Seong; Lee, Kwang Won; In, Sang Ryul; Jin, Jung-Tae; Chang, Dae-Sik; Oh, Byung-Hoon; Bae, Young-Soon; Kim, Jong-Su; Cho, Wook; Park, Hyun-Taek; Park, Young-Min; Yang, Hyung-Lyeol; Watanabe, Kazuhiro; Dairaku, Masayuki; Tobari, Hiroyuki; Kashiwagi, Mieko; Hanada, Masaya; Inoue, Takashi

2011-06-01

285

Quantitative analysis of the hydrogen peroxide formed in aqueous cigarette tar extracts  

SciTech Connect

We have established, for the first time, a reliable method to quantitate hydrogen peroxide (H{sub 2}O{sub 2}) generated in aqueous extracts of cigarette smoke tar. The aqueous tar extract was passed through a short reverse-phase column and its H{sub 2}O{sub 2} concentration determined by differential pulse polarography using an automatic reference subtraction system. The H{sub 2}O{sub 2} concentration increased with aging, pH and temperature; the presence of superoxide dismutase lead to lower H{sub 2}O{sub 2} concentrations. This method was applied to many kinds of research and commercial cigarettes. With a few exceptions, the amount of H{sub 2}O{sub 2} formed after a fixed time from each cigarette smoke was proportional to its tar yield.

Nakayama, T.; Church, D.F.; Pryor, W.A. (Louisiana State Univ., Baton Rouge (USA))

1989-01-01

286

EFFICIENCY OF DIOXIN RECOVERY FROM FLY ASH SAMPLES DURING EXTRACTION AND CLEANUP PROCESS  

EPA Science Inventory

The data from preliminary investigations of the efficiency of dioxin recovery from fly ash samples during sample extraction and subsequent column cleanup of sample extracts are discussed. teps of the extraction and the column cleanup procedures were evaluated by using radiolabele...

287

Separation of positional isomers by the use of coupled shape-selective stationary phase columns.  

PubMed

The successful separation of 2- and 3-methyl-substituted positional isomers of butanol, butyl acetate, and butanoic acid and its ethyl ester, is reported. These compounds are of interest in the study of wine flavour, however the separation of the 2- and 3-methyl isomers may present problems, and more so in the presence of the wine matrix components, when single capillary column gas chromatography (GC) is used. The strategy to achieve separation was based on the use of shape-selective cyclodextrin derivative (CDD) capillary columns (commonly referred to as chiral columns). These columns provide simultaneous resolution of the enantiomeric pairs of the 2-methyl isomers, and at the same time the ability to separate the 3-methyl isomer from the 2-methyl is achieved in all but the case of the ( S)-2- and 3-methylbutanol. The advantages of using shape-selective columns to perform this study is demonstrated, with coupling of two CDD columns giving improved separations of these compounds. Although these compounds are relatively volatile, cryogenic modulated comprehensive two-dimensional GC was shown to provide good pulsed peak profiles with chiral separation in the first dimension when a thicker film trapping column segment was employed. The components of interest were well separated from other wine matrix components. PMID:12638047

Shao, Yajing; Marriott, Philip

2003-03-01

288

Characterization of polyacrylamide based monolithic columns.  

PubMed

Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions. PMID:15354560

Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

2004-07-01

289

Transverse Reinforcement in Reinforced Concrete Columns  

NASA Astrophysics Data System (ADS)

In the article we are dealing with the influence of transverse reinforcement to the resistance of a cross-section of the reinforced concrete columns and also with the effective detailing of the column reinforcement. We are verifying the correctness of design guides for detailing of transverse reinforcement. We are also taking into account the diameter of stirrups and its influence over transverse deformation of column.

Grambli?ka, Štefan; Veróny, Peter

2013-11-01

290

Enzyme activities in the water column and in shallow permeable sediments from the northeastern Gulf of Mexico  

NASA Astrophysics Data System (ADS)

The activities of extracellular enzymes that initiate the microbial remineralization of high molecular weight organic matter were investigated in the water column and sandy surface sediments at two sites in the northeastern Gulf of Mexico. Six fluorescently labeled polysaccharides were hydrolyzed rapidly in the water column as well as in permeable sediments. This result contrasts with previous studies carried out in environments dominated by fine-grained muds, in which the spectrum of enzymes active in the water column is quite limited compared to that of the underlying sediments. Extracts of Spirulina, Isochrysis, and Thalassiosira were also used to measure hydrolysis rates in water from one of the sites. Rates of hydrolysis of the three plankton extracts were comparable to those of the purified polysaccharides. The broad spectrum and rapid rates of hydrolysis observed in the water column at both sites in the northeastern Gulf of Mexico may be due to the permeable nature of the sediments. Fluid flux through the sediments is sufficiently high that the entire 1.5 m deep water column could filter though the sediments on timescales of a few days to two weeks. Movement of water through sediments may also transport dissolved enzymes from the sediment into the water column, enhancing the spectrum as well as the rate of water column enzymatic activities. Such interaction between the sediments and water column would permit water column microbial communities to access high molecular weight substrates that might otherwise remain unavailable as substrates.

Arnosti, C.; Ziervogel, K.; Ocampo, L.; Ghobrial, S.

2009-09-01

291

A Final Column (Rainbow Teachers, Rainbow Students).  

ERIC Educational Resources Information Center

Presents, in a farewell column, some reflections on educational issues and movements concerning rainbow students, including self-esteem, story sharing, nonverbal differences, racial identification, and testing. (TB)

Brooks, Charlotte K.

1996-01-01

292

Interstitial gas effect on vibrated granular columns  

NASA Astrophysics Data System (ADS)

Vibrated granular materials have been intensively used to investigate particle segregation, convection, and heaping. We report on the behavior of a column of heavy grains bouncing on an oscillating solid surface. Measurements indicate that, for weak effects of the interstitial gas, the temporal variations of the pressure at the base of the column are satisfactorily described by considering that the column, despite the observed dilation, behaves like a porous solid. In addition, direct observation of the column dynamics shows that the grains of the upper and lower surfaces are in free fall in the gravitational field and that the dilation is due to a small delay between their takeoff times.

Pastenes, Javier C.; Géminard, Jean-Christophe; Melo, Francisco

2014-06-01

293

High current short pulse ion sources  

SciTech Connect

High current short pulse ion beams can be generated by using a multicusp source. This is accomplished by switching the arc or the RF induction discharge on and off. An alternative approach is to maintain a continuous plasma discharge and extraction voltage but control the plasma flow into the extraction aperture by a combination of magnetic and electric fields. Short beam pulses can be obtained by using a fast electronic switch and a dc bias power supply. It is also demonstrated that very short beam pulses ({approximately} 10 {micro}s) with high repetition rate can be formed by a laser-driven LaB{sub 6} or barium photo-cathode.

Leung, K.N. [Lawrence Berkeley National Lab., CA (United States). Accelerator and Fusion Research Div.

1996-08-01

294

Pulse Oximetry  

MedlinePLUS

... you are exercising or if you travel to high altitude. Having a pulse oximeter in these cases will allow you to monitor your blood oxygen level and know when you need to increase your supplemental oxygen flow rate. Ask your health care provider what oxygen ...

295

Effects of Column Conditions on the First-Order Rate Modeling of Nonequilibrium Solute Breakthrough  

NASA Astrophysics Data System (ADS)

First-order mass transfer models are commonly used as a means of interpreting sorption-related mass transfer in laboratory columns, often with the intent of approximating diffusion-based processes. We have fitted first-order model parameters to computer-simulated breakthrough curves from hypothetical column experiments in which Fickian diffusion into spherical particles limited the rate of sorption and desorption. Using both step and pulse inputs, we show that the fitted first-order coefficient is a function not only of the intrinsic diffusion rate, but also of the column length, the step experiment's duration, the input pulse width, the fluid velocity, and the solute retardation factor. For a range of typical column run conditions and a given diffusion rate, we show that the fitted first-order coefficient varies over three orders of magnitude in a manner roughly predictable through proper definition of a dimensionless timescale. In general, step inputs (as opposed to pulse inputs) provide a more consistent and predictable relationship between fitted coefficients and underlying diffusion rates. For either type of input, we recommend cautious use of the first-order model, since many observed variations in fitted rate constants are not the result of mechanistic phenomena.

Young, Dirk F.; Ball, William P.

1995-09-01

296

Synthesis of Ion Microbeam Column  

NASA Astrophysics Data System (ADS)

Electrostatic lenses have traditionally been designed by analyzing and combining different electrode configurations. Computational complexity typically limits such systems to a few geometrically simple elements, where the component interactions are neglected and not exploited to combat the various aberrations. Recently, Szilagyi and Szep have demonstrated that an axially symmetric column of circular plates, with the electrode potentials optimized for focusing, can surpass the typical conventional designs by many times in performance. Following the footsteps of pioneers like Burfoot and Hawkes, we partition the plates in order to transcend the limitations set by Scherzer's theorem on the chromatic and spherical aberrations of axially symmetric structures. Two algorithms, one based upon integral asymptotics and one upon the Levinson algorithm. for Toeplitz matrix inversion, are developed to complement the charge-density method in analyzing the new column structures. Various optimization schemes are combined to avoid shallow minima at a reasonable computational cost. With each plate partitioned into four sectors, we show that the interactions between the monopole and the quadrupole components can increase the output current density by more than 400% over the axially symmetric structure. By adjusting the sector potentials, we can realize systems capable of both focusing and deflecting the beam. In comparison to some existing designs, our systems excel in both performance and compactness, sometimes by many hundred percents. We then further partition the plates to generate the "octupole" deflectors and correctors. We show that the "octupole" deflectors can drastically slow down the beam degradation with deflection distance and that the correctors can further increase the output current density by more than 300%. Finally, we apply linear system theories to the study of the first-order properties of optical systems with different symmetries. We showed, without resorting to perturbational mathematics, that the higher multipole components, with more than 2 folds of rotational symmetry, can induce no first-order influences. We also find that there are systems with other symmetries that can replace an axially symmetric structure in the first-order approximation. This latter study is the beginning of our investigation for the optimum system geometry.

Mui, Peter Hon-Fung

1995-01-01

297

A CMOS integrated circuit for pulse-shaped discrimination  

Microsoft Academic Search

A CMOS integrated circuit (IC) for pulse-shape discrimination (PSD) has been developed. The IC performs discrimination of gamma-rays and neutrons as part of a system monitoring stored nuclear materials. The method implemented extracts the pulse tail decay time constant using a leading edge trigger for identifying the start of the pulse and a constant fraction discriminator (CFD) to determine the

S. S. Frank; M. N. Ericson; M. L. Simpson; R. A. Todd; D. P. Hutchinson

1995-01-01

298

Column Formation in Magnetorheological Fluids  

NASA Astrophysics Data System (ADS)

In 1990, Halsey and Toor identified a long-range attractive interaction between \\underbarinfinite chains of thermally fluctuating dipoles associated with Peierl's instability. It was suggested that this explained the formation of columns from single chains in dilute electrorheological fluids where the chains are effectively infinite due to image dipoles. In the approximation of Halsey and Toor, this attractive interaction term was independent of external field. In magnetorheological (MR) fluids there are no image dipoles and as a result, finite size corrections must be included. We show that these corrections give rise to a repulsive term which is also long ranged, and in addition grows roughly as the external field squared. The net effect of this term and the Halsey-Toor term is that the range of attraction between two MR chains (i) is typically only a couple of particle diameters and (ii) decreases as the external field increases. (i) and (ii) appear to be in gross contradiction with experiments on MR fluids. Analytical and numerical results will be presented in an attempt to solve this paradox.

Gross, Mark

1997-03-01

299

Wavelet transforms for optical pulse analysis.  

PubMed

An exploration of wavelet transforms for ultrashort optical pulse characterization is given. Some of the most common wavelets are examined to determine the advantages of using the causal quasi-wavelet suggested in Proceedings of the LEOS 15th Annual Meeting (IEEE, 2002), Vol. 2, p. 592, in terms of pulse analysis and, in particular, chirp extraction. Owing to its ability to distinguish between past and future pulse information, the causal quasi-wavelet is found to be highly suitable for optical pulse characterization. PMID:16396051

Vázquez, Javier Molina; Mazilu, Michael; Miller, Alan; Galbraith, Ian

2005-12-01

300

Column size effects of DER fluids  

NASA Astrophysics Data System (ADS)

The static yield stress of dielectric electrorheological (DER) fluids of infinite column state and chain state are calculated from the first principle method. The results indicate that the column surface contributions to ER effects is very small and both states will give correct results to the real DER fluids.

Zhao, T.; Ma, H. R.

2001-07-01

301

Results from the Winogradsky Column Study  

NSDL National Science Digital Library

This web page features research results from a student project involving Winogradsky Columns constructed using sandy sediment and water collected from an estuary in Massachusetts. The page includes high-resolution images of the columns and profiles of hydrogen sulfide and methane versus depth.

Science, Semester I.; Laboratory, Marine B.

302

Inelastic Buckling of Eccentrically Loaded Columns.  

National Technical Information Service (NTIS)

The inelastic buckling of eccentrically loaded simply supported columns of rectangular and circular cross sections is analyzed. The material of the column is assumed to satisfy Ramberg-Osgood's stress-strain relation. The load-carrying-capacity of the col...

N. C. Huang

1973-01-01

303

Seismic performance of bond controlled RC columns  

Microsoft Academic Search

An experimental investigation was carried out to examine the enhancement of seismic performances of reinforced concrete (RC) columns such as shear strength and ductility by controlling the bond of longitudinal reinforcements. Four 300×300 mm square RC columns with ordinary bonded reinforcements and completely unbonded reinforcements were tested under reversed cyclic loading. The test results showed that this method is very effective

G. R. Pandey; H. Mutsuyoshi; T. Maki

2008-01-01

304

Building a Winogradsky Column Video Demonstration  

NSDL National Science Digital Library

This five-minute Quick Time video demonstrates how to build a Winogradsky Column. The video is published by NASA Quest and can be used as a teaching supplement to classroom activities including the Winogradsky Column. This video requires Quick Time player to view, which can be downloaded on site.

Scalice, Daniella; Dodson, Karen; Quest, Nasa

305

Circulation in gas-slurry column reactors  

SciTech Connect

Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.

Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.

1990-08-15

306

Automated column equilibration, washing, sample loading and elution of bench-packed mini-columns.  

PubMed

In this paper we describe an easy and efficient way to pack mini-columns and use them in the Biomek 1000 Automated Laboratory Workstation. These procedures allow for automated column equilibration, column washing, sample loading and elution, and utilization of commercially available components. Various resins can be packed, allowing for automation of a variety of procedures in which minicolumns are used. PMID:1571139

Jagadeeswaran, P

1992-03-01

307

Composite Column Design/Test Lab  

NSDL National Science Digital Library

Effective engineered composite design activities require predictive and quantitative methodology. This research incorporates engineering design, using smart spreadsheets, into a laboratory activity focusing on columns made of composite materials. In a previous work, a laboratory activity was developed supporting composite design of polymer matrix composite beams. The present work applies a similar approach expanded to ceramic composites in the form of columns. In the lab, students simulate composite columns and use a smart spreadsheet to help optimize their design for engineering performance, including specific properties. Parameters are discussed and evaluated before the column is made. The composite is then fabricated. Finally, the composite is tested and the experimental data (critical load for columns) is compared to predictions.

Johnson, Craig

2009-09-22

308

Analysis of free and total myo-inositol in foods, feeds, and infant formula by high-performance anion exchange chromatography with pulsed amperometric detection, including a novel total extraction using microwave-assisted acid hydrolysis and enzymatic treatment.  

PubMed

A method for the analysis of free and total myo-inositol in foods, feeds, and infant formulas has been developed and validated using high-performance anion exchange chromatography with pulsed amperometric detection. The option of a free myo-inositol determination or a complete total myo-inositol determination from main bound sources can be achieved. These sources include phytates, lower'phosphorylated forms, and phosphatidylinositol. This approach gives the option for subtraction of myo-inositol from nonbioavailable sources when it is quantified using other methods if a total bioavailable myo-inositol result is desired for nutritional labeling of a product. The free analysis was validated in a milk-based infant formula, giving RSD(R) of 2.29% and RSD, of 2.06%. A mean recovery of 97.9% was achieved from various spike levels of myo-inositol. Certified National Institute of Standards and Technology reference material verified the method's compatibility and specificity. Two different total analyses were validated in a soy-based infant formula and compared. One technique involved using a conventional acid hydrolysis with autoclave incubation for 6 h, while the other used a novel technique of microwave-assisted acid hydrolysis with enzymatic treatment that can minimize extraction to 1 day. The autoclave analysis had RSD(R) of 2.08% and RSDr of 1.55%, along with a mean spike recovery of 102.1% at various myo-inositol spike levels. The microwave/enzyme total analysis had RSD(R) of 4.34% and RSD, of 4.70%, along with a mean spike recovery of 104.2% at various spike levels of myo-inositol. Main sources of myo-inositol including phytic acid and phosphatidylinositol were tested with both total analyses. Mean recoveries of phytic acid and phosphatidylinositol through the autoclave total analysis were 90.4 and 98.3%, respectively. Mean spike recoveries for these same sources in soy- based infant formula through the microwave/enzyme total analysis were 97.2 and 96.3%, respectively. Comparison of soy-based infant formula and corn grain samples with high levels of these main sources showed in similar results, indicating both total analyses are acceptable for use. An additional glycerol kinase step was also developed to remove glycerol from the chromatographic elution window of myoinositol in samples with high levels of glycerol. PMID:23175982

Ellingson, David; Pritchard, Ted; Foy, Pamela; King, Kathryn; Mitchell, Barbara; Austad, John; Winters, Doug; Sullivan, Darryl

2012-01-01

309

Extraction in aqueous two-phase systems of alkaline xylanase produced by Bacillus pumilus and its application in kraft pulp bleaching.  

PubMed

The aim of this work was to extract and to purify xylanase, produced by Bacillus pumilus from the crude fermentation broth, using aqueous two-phase systems (ATPS). The xylanase was extracted by partitioning in ATPS composed of phosphate and polyethylene glycol (PEG). The effect of tie-line length, PEG molecular mass and NaCl concentrations upon the purification factors and yields of xylanase were investigated by statistical design. The best system studied was that containing 22% PEG6000, 10% K2HPO4 and 12% NaCl with a purification factor of 33 and a 98% yield of enzyme activity. This system was also used for continuous extraction in a pulsed caps column. Subsequently, the xylanase from the crude fermentation broth was tested in hardwood kraft pulp bleaching. PMID:10942305

Bim, M A; Franco, T T

2000-06-23

310

Pulsed hydrojet  

DOEpatents

An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.

Bohachevsky, I.O.; Torrey, M.D.

1986-06-10

311

Digital Pulse  

NSDL National Science Digital Library

When high technology crashes into popular culture you've got Digital Pulse, the heartbeat of the infotainment infobahn with exclusive news and tips from the experts at CMP's Windows Magazine, NetGuide, Home PC and more. This week read about Adam Curry's deal with BMI which will let him sell (and us buy) digital recordings over the 'Net. Free registration is required on Pathfinder, Time Warner's home on the internet.

312

Pulse Consumption, Satiety, and Weight Management1  

PubMed Central

The prevalence of obesity has reached epidemic proportions, making finding effective solutions to reduce obesity a public health priority. One part of the solution could be for individuals to increase consumption of nonoilseed pulses (dry beans, peas, chickpeas, and lentils), because they have nutritional attributes thought to benefit weight control, including slowly digestible carbohydrates, high fiber and protein contents, and moderate energy density. Observational studies consistently show an inverse relationship between pulse consumption and BMI or risk for obesity, but many do not control for potentially confounding dietary and other lifestyle factors. Short-term (?1 d) experimental studies using meals controlled for energy, but not those controlled for available carbohydrate, show that pulse consumption increases satiety over 2–4 h, suggesting that at least part of the effect of pulses on satiety is mediated by available carbohydrate amount or composition. Randomized controlled trials generally support a beneficial effect of pulses on weight loss when pulse consumption is coupled with energy restriction, but not without energy restriction. However, few randomized trials have been conducted and most were short term (3–8 wk for whole pulses and 4–12 wk for pulse extracts). Overall, there is some indication of a beneficial effect of pulses on short-term satiety and weight loss during intentional energy restriction, but more studies are needed in this area, particularly those that are longer term (?1 y), investigate the optimal amount of pulses to consume for weight control, and include behavioral elements to help overcome barriers to pulse consumption.

McCrory, Megan A.; Hamaker, Bruce R.; Lovejoy, Jennifer C.; Eichelsdoerfer, Petra E.

2010-01-01

313

Comparison of Several Extraction Methods for the Isolation of Benzoic Acid Derivatives from Melissa officinalis  

Microsoft Academic Search

Several extraction techniques, such as Soxhlet extraction, solid phase extraction using molecularly imprinted polymer, matrix solid phase dispersion, and supercritical fluid extraction were evaluated for the isolation and purification of phenolic compounds, e.g., benzoic acids from natural samples of Melissa officinalis. The extracts of benzoic acids were analyzed by high performance liquid chromatography (HPLC) in reversed phase modus (C18 column)

Gabriela Karasová; Jozef Lehotay; Ewa K?odzinska; Bogus?aw Buszewski

2006-01-01

314

Pulsed atmospheric fluidized bed combustion. Technical progress report, July 1994--September 1994.  

National Technical Information Service (NTIS)

No changes in the process design were encountered during this period. Minor modifications in the combustor vessel and pulse combustor water jacket were made for ease of operation and maintenance. The combustor vessel column location in the foundation was ...

1994-01-01

315

[Study on gas chromatographic method for the evaluation of residual solvents by using wide bore open tubular columns].  

PubMed

A GC method using wide bore open tubular columns was developed to evaluate residual organic solvents. Sixteen organic solvents commonly used for pharmaceutical synthesis were analysed. The effects of different polarity columns and extraction solvents on the assay of residual solvents were studied in this work. It showed that most solvents can be well separated from each other on non-polar or less polar wide-bore columns. Extraction solvents differed in their extraction recovery and peak shape. Satisfactory results can be obtained when the proposed method was employed and a suitable extraction solvent was selected. The procedures summarized in this paper can be used as a guidance for the evaluation of residual organic solvents in bulk pharmaceuticals. PMID:12541657

Yao, Q; Li, Z W; Zhang, Q; Ye, L M

2001-03-01

316

Application of monolithic column in quantification of gliclazide in human plasma by liquid chromatography  

Microsoft Academic Search

A simple, rapid and sensitive isocratic reversed phase HPLC method with UV detection using a monolithic column has been developed and validated for the determination of gliclazide in human plasma. The assay enables the measurement of gliclazide for therapeutic drug monitoring with a minimum quantification limit of 10ngml?1. The method involves simple, one-step extraction procedure and analytical recovery was complete.

S. M. Foroutan; A. Zarghi; A. Shafaati; A. Khoddam

2006-01-01

317

Inspection on CFRP sheet with subsurface defects using pulsed thermographic technique  

NASA Astrophysics Data System (ADS)

The pulsed thermographic technique was used to detect flat-bottomed hole defects in CFRP sheet. Pulsed phase thermography (PPT) was used to extract the characteristic information of the thermal wave signal generated by thermal pulse. The difference of the phases between the sound and defective areas were analyzed. The defects' edges were extracted by Fuzzy C-Means clustering algorithm.

Chiwu, Bu; Qingju, Tang; Junyan, Liu; Yang, Wang

2014-07-01

318

Linear optical methods for temporal characterization of femtosecond UV pulses  

NASA Astrophysics Data System (ADS)

The realization of a first-order interferometric autocorrelator in a nearly collinear geometry is reported as an alternative method to measure the minimum pulse duration of femtosecond deep-UV laser pulses. The Fourier limited duration of 257-nm femtosecond pulses is measured with high accuracy, and compared to what obtained by spectrally measuring the bandwidth of the pulses. The agreement between the two methods is excellent, thus indicating the interferometric autocorrelator as a useful tool to extract the chirp of femtosecond UV pulses when used together with a second-order autocorrelator to measure the actual pulse duration.

Valadan, Mohammadhassan; D'Ambrosio, Davide; Gesuele, Felice; Velotta, Raffaele; Altucci, Carlo

2014-05-01

319

Lipid peroxidation of mitochondrial membrane induced by D 1: an organic solvent extractable component isolated from a crude extract of burn eschar  

Microsoft Academic Search

D1, an organic solvent extractable component of an extract from burn eschar was characterized and the mechanism of its inhibitory effect on mitochondrial respiratory functions was investigated. Using silicic acid column chromatography, it was found that D1 consisted of two parts: a toxic simple lipid and a non-toxic complex lipid. Six subunits were obtained by further silicic acid column chromatography,

Z. Chen; Y. Xiong; S. Lou; C. Shu

1996-01-01

320

Investigating Bacteria with the Winogradsky Column  

NSDL National Science Digital Library

This is an instructor's guide to teaching about biodiversity in the microbial world. This activity encourages students to investigate bacteria using a Winogradsky Column. Students can create a unique environment with slight variations on the recipe; and soon have an inquiry project that could easily occupy the entire year. With the simple extensions given, teachers can isolate and grow a number of the species found in the column and extend this column to a number of examples in the real world showing the relevance of this complex yet deceptively simple lab.

Rogan, Brian

2010-02-18

321

Method of extracting tetrodotoxin  

US Patent & Trademark Office Database

The present invention relates to a new process of extracting tetrodotoxin from the tissues of an organism. The invention provides increased yield of tetrodotoxin from animal tissues. In the invention, a lixiviated solution is obtained by soaking the tissues with water and a weak organic acid. Soluble proteins are removed by heating the lixiviated solution at a temperature below the boiling point. After pH adjustment, the solution is passed through a cation exchange column. Inorganic salts and alkaline amino acids are removed, and then the tetrodotoxin is adsorbed and eluted from activated carbon. The tetrodotoxin is crystallized by adjusting the pH to 8-10.

2003-04-22

322

Extraction Chromatographic Methods in the Sample Preparation Sequence for Thermal Ionization Mass Spectrometric Analysis of Plutonium Isotopes  

Microsoft Academic Search

A sample preparation sequence for actinide isotopic analysis by TIMS is described that includes column-based extraction chromatography as the first separation step, followed by anion exchange column separations. The sequence is designed to include a wet ashing step after the extraction chromatography to prevent any leached extractant or oxalic acid eluent reagents from interfering with subsequent separations, source preparation, or

Jay W. Grate; Matthew J. OHara; Anne F. Farawila; Matthew Douglas; Morgan M. Haney; Steve L. Peterson; Tapas C. Maiti; Christopher L. Aardahl

2011-01-01

323

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...

324

Tapered pulse tube for pulse tube refrigerators  

DOEpatents

Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

Swift, Gregory W. (Sante Fe, NM); Olson, Jeffrey R. (San Mateo, CA)

1999-01-01

325

Separation of fructooligosaccharides using zeolite fixed bed columns.  

PubMed

Recent studies have shown that the chromatographic separation of mixtures of monosaccharides and disaccharides may be improved by employing Y zeolites, a procedure which holds promise in the separation of oligosaccharides. In the present study, a column packed with zeolite was employed to study the separation of fructooligosaccharides (FOS). FOS were produced by an enzyme isolated from Rhodotorula sp., which produces GF2 (kestose), GF3 (nystose) and GF4 (frutofuranosyl nystose). The identification and quantification of the sugars were carried out by ion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The separation of fructooligosaccharides was carried out using a fixed bed column packed with Ba2+-exchange Y zeolites. The effects of temperature (40-50 degrees C), injected volume per bed volume (2.55-7.64%), superficial velocity (0.1-0.15 cm min(-1)) and eluent composition (40-60% ethanol) were investigated using a fractionary factorial design with separation efficiency as the response. The results showed that the most favorable conditions for the separation of the oligosaccharide-glucose mixture were 60% ethanol as eluent, temperature of 50 degrees C, superficial velocity of 0.1 cm min(-1) and 2.55% injection volume per bed volume of injection mixture, using two columns in series. The values for separation efficiency were 0.60 for oligosaccharide-glucose, 1.00 for oligosaccharide-fructose, 0.22 for oligosaccharide-sucrose, 0.43 for glucose-fructose, 0.82 for glucose-sucrose and 1.23 for fructose-sucrose. PMID:20617538

Kuhn, Raquel Cristine; Maugeri Filho, Francisco

2010-07-15

326

Separation of fructooligosaccharides using zeolite fixed bed columns.  

PubMed

Recent studies have shown that the chromatographic separation of mixtures of monosaccharides and disaccharides may be improved by employing Y zeolites, a procedure which holds promise in the separation of oligosaccharides. In the present study, a column packed with zeolite was employed to study the separation of fructooligosaccharides (FOS). FOS were produced by an enzyme isolated from Rhodotorula sp., which produces GF(2) (kestose), GF(3) (nystose) and GF(4) (frutofuranosyl nystose). The identification and quantification of the sugars were carried out by ion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The separation of fructooligosaccharides was carried out using a fixed bed column packed with Ba(2+)-exchange Y zeolites. The effects of temperature (40-50 degrees C), injected volume per bed volume (2.55-7.64%), superficial velocity (0.1-0.15cmmin(-1)) and eluent composition (40-60% ethanol) were investigated using a fractionary factorial design with separation efficiency as the response. The results showed that the most favorable conditions for the separation of the oligosaccharide-glucose mixture were 60% ethanol as eluent, temperature of 50 degrees C, superficial velocity of 0.1cmmin(-1) and 2.55% injection volume per bed volume of injection mixture, using two columns in series. The values for separation efficiency were 0.60 for oligosaccharide-glucose, 1.00 for oligosaccharide-fructose, 0.22 for oligosaccharide-sucrose, 0.43 for glucose-fructose, 0.82 for glucose-sucrose and 1.23 for fructose-sucrose. PMID:20646969

Kuhn, Raquel Cristine; Filho, Francisco Maugeri

2010-06-01

327

PSR extraction kicker system improvements  

SciTech Connect

A program to improve the reliability of hardware required to operate the Los Alamos Proton Storage Ring has been under way for the past three years. The extraction kicker system for the PSR was identified as one candidate for improvement. Pulse modulators produce 50kV pulses 360 nsec in length at up to 24-Hz pulse repetition rate and drive two 4-meter-long stripline electrodes. Sources of difficulty with this system included short width switch tube lifetime, drive cable electrical breakdown, high-voltage connector failure, and occasional electrode breakdown. This paper discusses modifications completed on this system to correct these difficulties. 2 refs., 3 figs.

Hardek, T.W.

1991-01-01

328

Evaluation of cyclooxygenase-2 inhibitors using pulsed ultrafiltration mass spectrometry.  

PubMed

Since selective inhibition of the inducible form of cyclooxygenase (COX-2) might retain all the benefits of classical nonsteroidal antiinflammatory agents while avoiding the major side effects associated with inhibition of the constitutive isoform COX-1, COX-2 has become an important target for the discovery and development of new antiinflammatory drugs. To aid in the discovery and characterization of such selective inhibitors, we have applied a mass spectrometry-based screening technique, pulsed ultrafiltration mass spectrometry, using COX-2 as the target. In a blind study, 18 samples enriched with one or more inhibitors of COX-2 were evaluated. The matrixes for the test samples consisted of DMSO, r DMSO solutions of a plant extract, or a bacterial fermentation broth extract. The composition of the samples was unknown during the assays, as were the concentrations of the COX-2 inhibitors. A soluble recombinant form of human COX-2 was incubated with each sample, and then an aliquot of each mixture was injected into the stirred ultrafiltration chamber fitted with a 30000 MW cutoff ultrafiltration membrane. After the unbound and weakly bound compounds were washed away, the ligand-receptor complexes were disrupted using an acidified 10% methanol solution. The released ligands were trapped on a C18 cartridge and then identified using liquid chromatography-negative ion electrospray mass spectrometry with the trapping cartridge as the HPLC column. Neither the plant matrix nor the fermentation broth extract were found to interfere with the assay. Two or three ligands for COX-2 were identified in each sample, which included polar and nonpolar compounds and inhibitors with IC50 values ranging from 100 microM to 10 nM. PMID:10959973

Nikolic, D; Habibi-Goudarzi, S; Corley, D G; Gafner, S; Pezzuto, J M; van Breemen, R B

2000-08-15

329

Nucleic acid extraction from complex matrices  

US Patent & Trademark Office Database

The present disclosure describes an adsorbent and exemplary protocols for extracting nucleic acids, such as DNA and RNA, from complex matrices, such as stool samples and water samples. The adsorbent is activated charcoal coated with a material such as polyvinylpyrrolidone, dextran, or coconut flours. The adsorbent may be used in microcentrifuge spin columns, where it may be present as a slurry in a storage solution. The sample may be prepared by vortexing in a buffer solution, centrifuging, adding a protease to the supernatant, and passing the supernatant through a microcentrifuge spin column containing coated activated charcoal. The key components, including buffer, protease, and spin columns, may be packaged in a kit.

2013-11-05

330

Beam transfer and extraction at LAMPF II  

SciTech Connect

Protons will be single-turn extracted from the LAMPF II synchrotron at 30 Hz. On alternate pulses they will be single-turn injected into a storage ring. Both processes utilize fast kickers and Lambertson septum magnets. Half-integer resonant extraction will be used to slow-extract the beam from the storage ring over a time spread of 1/15 s. The slow extraction occurs using electrostatic wire and iron septa.

Colton, E.P.

1983-01-01

331

A reversed phase high performance liquid chromatography method for the determination of fumonisins B 1 and B 2 in food and feed using monolithic column and positive confirmation by liquid chromatography\\/tandem mass spectrometry  

Microsoft Academic Search

The development of a reversed phase high performance liquid chromatography fluorescence method for the determination of the mycotoxins fumonisin B1 and fumonisin B2 by using silica-based monolithic column is described. The samples were first extracted using acetonitrile:water (50:50, v\\/v) and purified by using a C18 solid phase extraction-based clean-up column. Then, pre-column derivatization for the analyte using ortho-phthaldialdehyde in the

Wejdan Shakir Khayoon; Bahruddin Saad; Baharuddin Salleh; Nor Azliza Ismail; Normaliza Hj Abdul Manaf; Aishah Abdul Latiff

2010-01-01

332

A Versatile, Automatic Chromatographic Column Packing Device  

ERIC Educational Resources Information Center

Describes an inexpensive apparatus for packing liquid and gas chromatographic columns of high efficiency. Consists of stainless steel support struts, an Automat Getriebmotor, and an associated three-pulley system capable of 10, 30, and 300 rpm. (MLH)

Barry, Eugene F.; And Others

1977-01-01

333

Micro-Column Arrays for Nanolithography.  

National Technical Information Service (NTIS)

The research program has made substantial advances in areas relevant to the use of low energy electron beams and microfabricated electron beam columns for high resolution lithography. The first was the development of novel cold field emission sources. Foc...

H. G. Craighead

1997-01-01

334

How to design baffle tray columns  

SciTech Connect

As with packed columns, well-known heat transfer equations can be used to estimate mass transfer efficiencies for baffle tray columns. Other variables that can be calculated using this method include: flooding capacity, pressure drop, number of transfer units (NTUs) and the height equivalent to a theoretical plate (HETP). Gas-liquid contacting columns containing simple baffles have been used in hydrocarbon processing industry plants for many years. Principal areas of application have been for contacting liquids containing suspended solids and for quenching hot gases with coolant liquids. They are advantageous for fouling services. But because of their simplistic design they have not been thought to produce high efficiencies for transferring mass or heat. When used primarily for mass transfer purposes, only a few theoretical stages have been expected of them. This paper discusses hydrodynamics, previous studies on the design of baffle tray columns, capacity, pressure drop, and mass transfer efficiency, and gives an example calculation of mass transfer efficiency.

Fair, J.R. (Univ. of Texas, Austin (United States))

1993-05-01

335

Preparative Sephadex Column Electrophoresis: An Improved Apparatus.  

National Technical Information Service (NTIS)

A preparative column electrophoresis using Sephadex G-25 as supporting medium offers a rapid and inexpensive method of purifying a large quantity of proteins with minimum sample loss. This apparatus has been very effective in separating closely related ho...

E. Kay J. H. C. Shih

1973-01-01

336

Shear strengthening of beam-column joints  

Microsoft Academic Search

Shear failure of beam-column joints is identified as the principal cause of collapse of many moment-resisting frame buildings during recent earthquakes. Effective and economical rehabilitation techniques for the upgrade of the joint shear-resistance capacity in existing structures are needed. The objective of this research is to develop effective selective rehabilitation schemes for reinforced concrete beam-column joints using advanced composite materials.

Ahmed Ghobarah; A. Said

2002-01-01

337

CMOS \\/ CMOL architectures for spiking cortical column  

Microsoft Academic Search

We present a spiking cortical column model based on neural associative memory, and demonstrate architectures for emulating the cortical column model with nanogrid molecular circuitry. We investigate a number of options for cost-effective hardware with digital CMOS and mixed-signal CMOL, a hybrid CMOS\\/nanogrid technology. We also give an example of a dynamic learning algorithm that is a suitable match to

Changjian Gao; Mazad S. Zaveri; Dan W. Hammerstrom

2008-01-01

338

Novel electrostatic column for ion projection lithography  

Microsoft Academic Search

Ion projection lithography (IPL) is being considered for high volume sub-0.25-[mu]m lithography. A novel ion-optical column has been designed for exposing 20[times]20 mm[sup 2] fields at 3[times] reduction from stencil mask to wafer substrates. A diverging lens is realized by using the stencil mask as the first electrode of the ion-optical column. The second and third electrode form an accelerating

A. Chalupka; G. Stengl; H. Buschbeck; G. Lammer; H. Vonach; R. Fischer; E. Hammel; H. Loeschner; R. Nowak; P. Wolf; W. Finkelstein; R. W. Hill; I. L. Berry; L. R. Harriott; J. Melngailis; J. C. Wolfe; H. Stroh; H. Wollnik; A. A. Mondelli; J. J. Petillo; K. Leung

1994-01-01

339

EVALUATION OF CAPILLARY SYSTEMS FOR THE ANALYSIS OF ENVIRONMENTAL EXTRACTS  

EPA Science Inventory

The quantitative and qualitative aspects of splitless and on-column capillary column injectors for the analysis of environmental extracts for priority pollutants are investigated. Precision data are presented for a wide variety of compounds introduced into a splitless injector by...

340

Ocular dominance columns in New World monkeys.  

PubMed

Squirrel monkeys normally lack ocular dominance columns in V1. This study shows that squirrel monkeys can exhibit clear ocular dominance columns if they are made strabismic within a few weeks of birth. Columns were seen only in layer 4C beta and were coarser than the overlying blob pattern in the same animal. In physiological recordings from layer 4C of a normal squirrel monkey, single units were mostly monocular, but units driven by the two eyes were intermixed. These results suggest that in squirrel monkeys activity-dependent mechanisms do normally segregate geniculate inputs from the two eyes, but on a much finer scale than in Old World primates. Strabismic owl monkeys also showed ocular dominance columns; normal owl monkeys showed variable expression. Because ocular dominance columns, when present in New World monkeys, tend to occur in later-maturing parts of layer 4C, I hypothesize that a difference in the relative timing of the maturation of geniculocortical inputs and intracortical lateral connectivity explains the variability of ocular dominance column expression in New World monkeys. PMID:8604053

Livingstone, M S

1996-03-15

341

Nuclear magnetic resonance studies of solvent flow through chromatographic columns: effect of packing density on flow patterns  

Microsoft Academic Search

NMR (nuclear magnetic resonance) techniques have been used to measure and characterise solvent flow through chromatographic columns. NMR imaging was used to track an injection of D2O. PGSE (pulsed gradient spin echo) NMR was used to measure the flow-rate dependence of axial and transverse apparent diffusion. A combination of these two techniques (dynamic NMR imaging) gave the spatial distribution of

Sally G. Harding; Herbert Baumann

2001-01-01

342

Liquid-induced pulsing flow in trickle-bed reactors  

Microsoft Academic Search

This contribution describes the experiments on pulse induction by cycling the liquid feed in a column of 3.2m height. Based on a square-wave cycled liquid feed, two feed strategies are developed that involve the artificial induction of natural pulses and a separation of the wetting efficiency in time. The feed strategies aim at increasing the mass transfer rate of the

J. G Boelhouwer; H. W Piepers; A. A. H Drinkenburg

2002-01-01

343

Preparation and performance of immobilized yeast cells in columns containing no inert carrier. [Schizosaccharomyces pombe  

SciTech Connect

Schizosaccharomyes pombe was cultivated in a medium of glucose (10 g/l), malt extract (3 g/l), yeast extract (3 g/l), and bactopeptone (5 g/l) to form flocs. More than 95% of the cell population were flocculated. Variation in glucose concentration (from 10 to 11 g/l) did not affect flocculation. Yeast extract helped induce flocculation. Application of the immobilized yeast for the continuous production of ethanol was tested in a column reactor. Soft yeast flocs (50-200 mesh) underwent morphological changes to heavy particles (0.1-9.3 cm diameter) after continuously being fed with fresh substrates in the column. Productivity as high as 87 g EtOH/l/hour was obtained when a 150 g/l glucose medium was fed. The performance of this yeast reactor was stable over a two-month period. The ethanol yield was 97% of the theoretical maximum based upon glucose consumed. (Refs. 16).

Hsiao, H.Y.; Chiang, L.C.; Yang, C.M.; Chen, L.F.; Tsao, G.T.

1983-02-01

344

Countercurrent Nuclear-Fuel Liquid-Liquid Extraction Apparatus.  

National Technical Information Service (NTIS)

The solvent extraction apparatus is utilized in the processing of nuclear reactor fuel and blanket materials such as spent fuel rods from a nuclear reactor. The apparatus includes an elongated, cylindrical, vertical column. A heavy liquid inlet at the top...

J. P. Duckworth

1965-01-01

345

Column system using diaion HP2MG for determination of some metal ions by flame atomic absorption spectrometry  

Microsoft Academic Search

A column solid-phase extraction method for the preconcentration and determination of cadmium(II), copper(II), cobalt(II), iron(III), lead(II), nickel(II) and zinc(II) dithizone chelates by atomic absorption spectrometry has been described. Diaion HP-2MG was used as adsorbent for column studies. The influences of the various analytical parameters including pH of the aqueous solutions, amounts of ligand and resin were investigated for the retentions

Mustafa Tuzen; Mustafa Soylak

2004-01-01

346

Performance enhancement of R\\/C building columns and beam–column joints through shotcrete jacketing  

Microsoft Academic Search

This paper investigates the effectiveness and suitability of shotcrete and cast-in-place concrete as means of retrofitting columns and beam–column joints in reinforced concrete frame structures, so as to improve their shear and\\/or flexural performance. Thus, the use of four-sided and two-sided reinforced shotcrete or cast-in-place concrete jackets has been investigated experimentally for the case of pre-earthquake retrofitting of columns and

Alexander-Dimitrios G. Tsonos

2010-01-01

347

Generation of short and intense attosecond pulses  

NASA Astrophysics Data System (ADS)

Extremely broad bandwidth attosecond pulses (which can support 16as pulses) have been demonstrated in our lab based on spectral measurements, however, compensation of intrinsic chirp and their characterization has been a major bottleneck. In this work, we developed an attosecond streak camera using a multi-layer Mo/Si mirror (bandwidth can support ˜100as pulses) and position sensitive time-of-flight detector, and the shortest measured pulse was 107.5as using DOG, which is close to the mirror bandwidth. We also developed a PCGPA based FROG-CRAB algorithm to characterize such short pulses, however, it uses the central momentum approximation and cannot be used for ultra-broad bandwidth pulses. To facilitate the characterization of such pulses, we developed PROOF using Fourier filtering and an evolutionary algorithm. We have demonstrated the characterization of pulses with a bandwidth corresponding to ˜20as using synthetic data. We also for the first time demonstrated single attosecond pulses (SAP) generated using GDOG with a narrow gate width from a multi-cycle driving laser without CE-phase lock, which opens the possibility of scaling attosecond photon flux by extending the technique to peta-watt class lasers. Further, we generated intense attosecond pulse trains (APT) from laser ablated carbon plasmas and demonstrated ˜9.5 times more intense pulses as compared to those from argon gas and for the first time demonstrated a broad continuum from a carbon plasma using DOG. Additionally, we demonstrated ˜100 times enhancement in APT from gases by switching to 400 nm (blue) driving pulses instead of 800 nm (red) pulses. We measured the ellipticity dependence of high harmonics from blue pulses in argon, neon and helium, and developed a simple theoretical model to numerically calculate the ellipticity dependence with good agreement with experiments. Based on the ellipticity dependence, we proposed a new scheme of blue GDOG which we predict can be employed to extract intense SAP from an APT driven by blue laser pulses. We also demonstrated compression of long blue pulses into >240 microJ broad-bandwidth pulses using neon filled hollow core fiber, which is the highest reported pulse energy of short blue pulses. However, compression of phase using chirp mirrors is still a technical challenge.

Khan, Sabih Ud Din

348

Nanosecond, kilovolt pulse generators  

Microsoft Academic Search

Nanosecond pulse generators, which provide kilovolt pulses, are required for applications such as pulsed lasers, electro-optical devices, electron heating of plasmas, and bioelectrics. Switches used to generate such short pulses include high-pressure spark gaps, photoconductive switches and semiconductor opening switches. Most of the pulse generators based on these switch technologies are designed for high voltage, high power applications. We have

U. Hahn; M. Herrmann; F. Leipold; K. H. Schoenbach

2001-01-01

349

Determination of a new atypical antipsychotic agent perospirone and its metabolite in human plasma by automated column-switching high-performance liquid chromatography  

Microsoft Academic Search

A simple and sensitive column-switching high-performance liquid chromatographic (HPLC) method with fluorescence detection is described for the quantification of perospirone, a serotonin and dopamine antagonist, and its metabolite ID-15036 in human plasma. The test compounds were extracted from 2 ml of plasma using chloroform–hexane (30:70, v\\/v) and the extract was injected into a column I (TSK-PW precolumn, 10 ?m, 35×4.6

Norio Yasui-Furukori; Yoshimasa Inoue; Tomonori Tateishi

2003-01-01

350

Automated metal-free multiple-column nanoLC for improved phosphopeptide analysis sensitivity and throughput  

SciTech Connect

We report on the development and characterization of an automated metal-free nanoscale multiple-capillary system for reversed-phase liquid chromatography-mass spectrometry analysis of phosphopeptides. The system incorporates a capillary column (50 um i.d. × 30 cm, packed with 5 um C18 particles) coupled on-line to a solid phase extraction column (150 um i.d. × 4 cm, packed with 5 um C18 particles). Electrospray ionization tips are constructed on the packed capillary column to couple the reversed-phase liquid chromatographic separation to a linear ion trap tandem mass spectrometer.

Zhao, Rui; Ding, Shi-Jian; Shen, Yufeng; Camp, David G.; Livesay, Eric A.; Udseth, Harold R.; Smith, Richard D.

2009-03-15

351

Intensified extraction of ionized natural products by ion pair centrifugal partition extraction  

Microsoft Academic Search

The potential of centrifugal partition extraction (CPE) combined with the ion-pair (IP) extraction mode to simultaneously extract and purify natural ionized saponins from licorice is presented in this work. The design of the instrument, a new laboratory-scale Fast Centrifugal Partition Extractor (FCPE300®), has evolved from centrifugal partition chromatography (CPC) columns, but with less cells of larger volume. Some hydrodynamic characteristics

Mahmoud Hamzaoui; Jane Hubert; Jamila Hadj-Salem; Bernard Richard; Dominique Harakat; Luc Marchal; Alain Foucault; Catherine Lavaud; Jean-Hugues Renault

2011-01-01

352

Formation of pulses with controlled parameters in a resonance microwave compressor employing oscillation-mode transformation  

NASA Astrophysics Data System (ADS)

Results of an experimental study of the formation of rf pulses with controlled power, duration, repetition rate, and envelope parameters in a resonance compressor employing oscillation-mode transformation are presented. The pulse parameters are varied by using tuned intermodal coupling elements. A possibility of the formation of a series of subsecond and nanosecond rf pulses in the partial extraction of energy and nanosecond pulses of various durations in single complete extraction of energy from the compressor resonator is shown.

Avgustinovich, V. A.; Artemenko, S. N.; Igumnov, V. S.; Yushkov, Yu. G.

2013-09-01

353

Characterizing gaseous flow in submicron chromatography columns.  

SciTech Connect

Enormous interest exists to develop the next generation of an integrated microsystem for chemical and biological analysis ({mu}ChemLab{trademark}) and to further reduce the volume of the system. One approach is to scale down the size of critical components and to explore any pumping mechanism that can minimize the power requirement. Since the majority of the pumping requirement is to overcome the wall resistance in the gas chromatography (GC) column, our attention is to study the gas flow in this GC column. As the column dimension decreases, the gaseous flow will go from a continuum regime into a non-continuum regime; i.e., slip, transition, and free molecular regimes. Thus it is very important to well characterize the gaseous flow in submicron columns and to understand its flow behavior. Specifically, in this study, our focus is to investigate the effects of viscosity, rarefaction, and compressibility as the column dimension decreases. Both theoretical predictions and experimental results will be presented.

Wong, Chung-Nin Channy

2003-05-01

354

Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore  

NASA Astrophysics Data System (ADS)

Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.

Darezereshki, E.; Schaffie, M.; Lotfalian, M.; Seiedbaghery, S. A.; Ranjbar, M.

2011-04-01

355

PSR beam-pulse formation and control  

SciTech Connect

The Proton Storage Ring (PSR) is a major addition to the Weapons Neutron Research Facility (WNR) at LAMPF. It will act as a bunch compressor for the relatively long linac macropulses from LAMPF, tailoring them into short, intense pulses ideally suited for neutron-scattering research. This paper concentrates on the methods used to form these pulses before injection into the linac, to multiplex the PSR beam with other LAMPF users, and to synchronize the storage ring with pulse arrival time at injection and with the WNR mechanical neutron chopper at extraction.

Hardekopf, R.A.

1983-01-01

356

Femto-second pulses of synchrotron radiation  

SciTech Connect

A method capable of producing femto-second pulses of synchrotron radiation is proposed. It is based on the interaction of femto-second light pulses with electrons in a storage ring. The application of the method to the generation of ultra-short x-ray pulses at the Advance Light Source of Lawrence Berkeley National Laboratory has been considered. The same method can also be used for extraction of electrons from a storage ring in ultra-short series of microbunches spaced by the periodicity of light wavelength.

Zholents, A.A. [Lawrence Berkeley Lab., CA (United States); Zolotorev, M.S. [Stanford Univ., CA (United States)

1995-07-01

357

The characteristics of open-tubular capillary electrochromatography columns with series/mixed stationary phases constructed with magnetic nanoparticle coating.  

PubMed

Novel open-tubular capillary electrochromatography (OT-CEC) systems with core/shell magnetic nanoparticles modified by amino or C18 groups as stationary phase were constructed by immobilizing nanoparticles in the capillary with permanent magnets. Influence of preparation method of OT-CEC column with series stationary phases (continuous two-dimension) on column performance and effect of dispersant on capability of OT-CEC column prepared by stationary phases with mixed functionalities (mixed stationary phases) were investigated in details to achieve stable preparation. Organic acids were used to evaluate the OT-CEC systems, and the relative column efficiency of salicylic acid was 420,000 plates/m for series stationary phases, while that of benzoic acid reached 480,000 plates/m for mixed stationary phases. The excellent within-column and between-column repeatability (n=5) testified with the RSDs of retention time were less than 0.44% and 10.20% for series stationary phases and 1.65% and 4.29% for mixed stationary phases. The two OT-CEC systems were further applied to separation of the aqueous extract of Rhizoma gastrodiae. Comparing with normal OT capillary column, the new systems show extra high column efficiency due to large surface areas of nanoparticles and multiple separation mechanisms, and they have great potential in the method development for the analysis of complicated samples. PMID:23597906

Zhu, Yaxian; Zhang, Lingyi; Qian, Junhong; Zhang, Weibing

2013-01-30

358

Silicon microcolumn arrays grown by nanosecond pulsed-excimer laser irradiation  

NASA Astrophysics Data System (ADS)

Arrays of high aspect ratio silicon microcolumns that protrude well above the initial surface have been formed by cumulative nanosecond pulsed-excimer laser irradiation of silicon. Microcolumn growth is strongly affected by the gas environment, being enhanced in air or other oxygen-containing ambient. It is proposed that microcolumn growth occurs through a combination of pulsed-laser melting of the tips of the columns and deposition of silicon from the intense flux of silicon-rich vapor produced by ablation of the surface regions between columns. The molten tips of the columns are strongly preferred sites for deposition, resulting in a very high axial growth rate. The growth process is conceptually similar to the vapor-liquid-solid method used to grow silicon whiskers. However, in the present case the pulsed-laser radiation fulfills two roles almost simultaneously, viz., providing the flux of silicon-containing molecules and melting the tips of the columns.

Pedraza, A. J.; Fowlkes, J. D.; Lowndes, D. H.

1999-04-01

359

Ionization instability in a turbulent plasma column  

SciTech Connect

The problem of the onset of ionization waves in a turbulent plasma column is studied using linear stability theory. A mathematical model of the mutual interactions between the gas flow turbulence, Joule heating, ionization and ambipolar diffusion in the cylindrical plasma column is developed. Axially homogeneous stationary solutions of the turbulent plasma column are presented. These solutions are then perturbed and their stability to longitudinal disturbances is investigated. The growth rate of the disturbances is calculated for argon at a pressure of 50 torr, a range of currents between 0.2 and 2 A and Reynolds number values of 0, 6000 and 10,000. It is found that the gas turbulence delays the onset of ionization waves for a wide range of discharge currents. 20 refs.

Crispin, Y. (Florida, University, Gainesville (United States))

1992-01-01

360

Non-planar microfabricated gas chromatography column  

DOEpatents

A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

Lewis, Patrick R. (Albuquerque, NM); Wheeler, David R. (Albuquerque, NM)

2007-09-25

361

Cadmium removal in a biosorption column  

SciTech Connect

New biosorbent material derived from a ubiquitous brown marine alga Ascophyllum nodosum has been examined in packed-bed flow-through sorption columns. It effectively removed 10 mg/L of cadmium down to 1.5 ppb levels in the effluent, representing 99.985% removal. The experimental methodology used was based on the early Bohart and Adams sorption model, resulting in quantitative determination of the characteristic process parameters which can be used for performance comparison and process design. An average metal loading of the biosorbent (N[sub 0]) determined was 30 mg Cd/g, corresponding closely to that observed for the batch equilibrium metal concentration of 10 mg Cd/L. The critical bed depth (D[sub min]) for the potable water effluent quality standard varied with the column feed flow rate from 20 to 50 cm. The sorption column mass transfer and dispersion coefficients were determined, which are also required for solving the sorption model equations.

Volesky, B.; Prasetyo, I. (McGill Univ., Montreal, Quebec (Canada). Dept. of Chemical Engineering)

1994-05-01

362

Phase-coherent light pulses for atom optics and interferometry.  

PubMed

We have developed a novel source for the generation of powerful phase-coherent light pulses. Our setup uses an acousto-optic modulator (AOM) inside an external high-finesse resonator. By applying a short rf pulse to the AOM, we dump the cavity and extract a large part of the stored and enhanced power within a short optical pulse and with a controllable optical phase. In preliminary experiments we reached 100 W of peak power in a 15-ns optical pulse. The mutual phase coherence of successive light pulses is demonstrated with a molecular iodine interferometer experiment in a cell. PMID:18188346

Heupel, T; Weitz, M; Hänsch, T W

1997-11-15

363

Final Report, Distillation Column Flooding Predictor  

SciTech Connect

The Flooding Predictor is an advanced process control strategy comprising a patented pattern-recognition methodology that identifies pre-flood patterns discovered to precede flooding events in distillation columns. The grantee holds a U.S. patent on the modeling system. The technology was validated at the Separations Research Program, The University of Texas at Austin under a grant from the U. S. Department of Energy, Inventions & Innovation Program. Distillation tower flooding occurs at abnormally high vapor and/or liquid rates. The loss in tray efficiencies is attributed to unusual behavior of liquid inventories inside the column leading to conditions of flooding of the space in between trays with liquid. Depending on the severity of the flood condition, consequences range from off spec products to equipment damage and tower shutdown. This non-intrusive pattern recognition methodology, processes signal data obtained from existing column instrumentation. Once the pattern is identified empirically, it is modeled and coded into the plant's distributed control system. The control system is programmed to briefly "unload" the tower each time the pattern appears. The unloading takes the form of a momentary reduction in column severity, e.g., decrease bottom temperature, reflux or tower throughput. Unloading the tower briefly at the pre-flood state causes long-term column operation to become significantly more stable - allowing an increase in throughput and/or product purity. The technology provides a wide range of value between optimization and flooding. When a distillation column is not running at capacity, it should be run in such a way ("pushed") that optimal product purity is achieved. Additional benefits include low implementation and maintenance costs, and a high level of console operator acceptance. The previous commercial applications experienced 98% uptime over a four-year period. Further, the technology is unique in its ability to distinguish between different flooding mechanisms within the same tower, e.g., liquid and jet flooding.

George E. Dzyacky

2003-05-31

364

Larvicidal activity of saponin containing extracts and fractions of fruit mesocarp of Balanites aegyptiaca  

Microsoft Academic Search

Chloroform, ethyl acetate, butanol and methanol extracts of fruit mesocarp of Balanites aegyptiaca and five fractions from the methanol extract were tested against the Aedes aegypti mosquito larvae. All extracts showed larvicidal effects however the highest larval mortality was found in methanol extract. One fraction obtained from the silica gel column chromatography of the latter was found most effective for

Zeev Wiesman; Bishnu P. Chapagain

2006-01-01

365

Pulse-burst laser systems for fast Thomson scattering (invited)  

SciTech Connect

Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to ''pulse-burst'' capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned.

Den Hartog, D. J. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Ambuel, J. R.; Holly, D. J.; Robl, P. E. [Physical Sciences Laboratory, University of Wisconsin-Madison, 3725 Schneider Drive, Stoughton, Wisconsin 53589 (United States); Borchardt, M. T.; Falkowski, A. F.; Harris, W. S.; Parke, E.; Reusch, J. A.; Stephens, H. D.; Yang, Y. M. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

2010-10-15

366

Pulse-burst laser systems for fast Thomson scattering (invited).  

PubMed

Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned. PMID:21033868

Den Hartog, D J; Ambuel, J R; Borchardt, M T; Falkowski, A F; Harris, W S; Holly, D J; Parke, E; Reusch, J A; Robl, P E; Stephens, H D; Yang, Y M

2010-10-01

367

Laboratory studies of water column separation  

NASA Astrophysics Data System (ADS)

Results of experimental studies of water column separation following an upstream valve closure are presented. Different geometrical arrangements with transparent PVC pipes are installed immediately downstream of the closing valve, namely, horizontal pipes, vertical pipes flowing down, and humpback profile pipes, the last two being used in order to obtain full pipe section vapor cavities. Maximum over pressures at water column rejoining, and maximum cavity lengths and duration, are compared with theoretical values and with previous experiments with horizontal pipes. Good agreement is found between theory and experiments, and interesting visual material is obtained.

Autrique, R.; Rodal, E.

2013-12-01

368

Optical Measurement Technique for Space Column Characterization  

NASA Technical Reports Server (NTRS)

A simple optical technique for the structural characterization of lightweight space columns is presented. The technique is useful for determining the coefficient of thermal expansion during cool down as well as the induced strain during tension and compression testing. The technique is based upon object-to-image plane scaling and does not require any photogrammetric calibrations or computations. Examples of the measurement of the coefficient of thermal expansion are presented for several lightweight space columns. Examples of strain measured during tension and compression testing are presented along with comparisons to results obtained with Linear Variable Differential Transformer (LVDT) position transducers.

Barrows, Danny A.; Watson, Judith J.; Burner, Alpheus W.; Phelps, James E.

2004-01-01

369

Cross flow cyclonic flotation column for coal and minerals beneficiation  

Microsoft Academic Search

An apparatus and process for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate

Ralph W. Lai; Robert A. Patton

2000-01-01

370

Cross flow cyclonic flotation column for coal and minerals beneficiation  

Microsoft Academic Search

An apparatus and process are disclosed for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used

R. W. Lai; R. A. Patton

2000-01-01

371

Cross flow flotation column for coal and minerals beneficiation  

Microsoft Academic Search

An apparatus and process are disclosed for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used

Ralph W. Lai; Robert A. Patton

1997-01-01

372

Dual Column Operation for Gas Chromatograph-Mass Spectrometer.  

National Technical Information Service (NTIS)

An arrangement to operate dual columns, i.e. a capillary and a packed column in a gas chromatograph-mass spectrometer is described. The packed column provides the make-up for the capillary column so that the molecular separator can be retained in the syst...

L. Kazyak

1976-01-01

373

Column bioleaching of uranium embedded in granite porphyry by a mesophilic acidophilic consortium.  

PubMed

A mesophilic acidophilic consortium was enriched from acid mine drainage samples collected from several uranium mines in China. The performance of the consortium in column bioleaching of low-grade uranium embedded in granite porphyry was investigated. The influences of several chemical parameters on uranium extraction in column reactor were also investigated. A uranium recovery of 96.82% was achieved in 97 days column leaching process including 33 days acid pre-leaching stage and 64 days bioleaching stage. It was reflected that indirect leaching mechanism took precedence over direct. Furthermore, the bacterial community structure was analyzed by using Amplified Ribosomal DNA Restriction Analysis. The results showed that microorganisms on the residual surface were more diverse than that in the solution. Acidithiobacillus ferrooxidans was the dominant species in the solution and Leptospirillum ferriphilum on the residual surface. PMID:21316943

Qiu, Guanzhou; Li, Qian; Yu, Runlan; Sun, Zhanxue; Liu, Yajie; Chen, Miao; Yin, Huaqun; Zhang, Yage; Liang, Yili; Xu, Lingling; Sun, Limin; Liu, Xueduan

2011-04-01

374

Chromatographic separation of arsenic species with pentafluorophenyl column and application to rice.  

PubMed

Arsenic species, including arsenous acid, arsenic acid, methylarsonic acid, and dimethylarsinic acid, were determined using HPLC-ICPMS. The species were separated with a Discovery HS F5 column and a simple, volatile, and isocratic mobile phase of 0.1% (v/v) formic acid and 1% (v/v) methanol. The Discovery HS F5 column with a pentafluorophenyl (PFP) stationary phase gave sharp peaks and full separation of the arsenic species in 5min, and other PFP columns showed lower performance. This separation method was applied to arsenic species analysis in rice. The extraction of arsenic from rice samples was performed using 0.15M nitric acid. The methodology was validated by use of certified reference materials, NMIJ CRM 7503-a and NIST SRM 1568a, and extremely low arsenic rice samples as blank samples. PMID:24947890

Baba, Koji; Arao, Tomohito; Yamaguchi, Noriko; Watanabe, Eiki; Eun, Heesoo; Ishizaka, Masumi

2014-08-01

375

Long pulse production from short pulses  

DOEpatents

A method of producing a long output pulse (SA) from a short pump pulse (P), using an elongated amplified fiber (11) having a doped core (12) that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding 13. A seed beam (S) of the longer wavelength is injected into the core (12) at one end of the fiber (11) and a pump pulse (P) of the shorter wavelength is injected into the cladding (13) at the other end of the fiber (11). The counter-propagating seed beam (S) and pump pulse (P) will produce an amplified output pulse (SA) having a time duration equal to twice the transit time of the pump pulse (P) through the fiber (11) plus the length of the pump pulse (P).

Toeppen, John S. (Livermore, CA)

1994-01-01

376

Long pulse production from short pulses  

DOEpatents

A method of producing a long output pulse from a short pump pulse is disclosed, using an elongated amplified fiber having a doped core that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding. A seed beam of the longer wavelength is injected into the core at one end of the fiber and a pump pulse of the shorter wavelength is injected into the cladding at the other end of the fiber. The counter-propagating seed beam and pump pulse will produce an amplified output pulse having a time duration equal to twice the transit time of the pump pulse through the fiber plus the length of the pump pulse. 3 figs.

Toeppen, J.S.

1994-08-02

377

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components.  

DOEpatents

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Egorov, Oleg B. (Richland, WA); O'Hara, Matthew J. (Richland, WA); Grate, Jay W. (West Richland, WA); Chandler, Darrell P. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Bruckner-Lea, Cynthia J. (Richland, WA)

2004-08-24

378

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components  

DOEpatents

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Egorov, Oleg B. (Richland, WA); O'Hara, Matthew J. (Richland, WA); Grate, Jay W. (West Richland, WA); Chandler, Darrell P. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Bruckner-Lea, Cynthia J. (Richland, WA)

2006-02-21

379

Systems for column-based separations, methods of forming packed columns, and methods of purifying sample components  

DOEpatents

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Egorov, Oleg B. (Richland, WA); O'Hara, Matthew J. (Richland, WA); Grate, Jay W. (West Richland, WA); Chandler, Darrell P. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Bruckner-Lea, Cynthia J. (Richland, WA)

2000-01-01

380

Evaluation and application of liquid chromatographic columns coated with 'intelligent' ligands. II. Phospholipid column.  

PubMed

The stationary phases of octadecylsilica (ODS) coated with phospholipid have been developed as a model of artificial lipid membranes for liquid chromatographic columns. An ODS column coated with phospholipid can be readily prepared by recycling a solution containing L-alpha-dipalmitoyl-phosphatidylcholine (DPPC) through an ODS column in a closed loop. DPPC becomes absorbed on the ODS surfaces by hydrophobic interaction between the acyl group of DPPC and the octadecyl group of the ODS surfaces. The DPPC column was usable when a mobile phase containing 30% (v/v) acetonitrile was delivered without detachment of the DPPC from the ODS surfaces. The retention behavior of ionic solutes on the DPPC column suggested that the retention was based on both ionic and electrostatic interactions between the solutes and the stationary phase. The retention factors on the DPPC column correlated well with the partition coefficients in liposome systems for alpha-adrenoceptor agonists and beta-blockers, indicating that the partition of solutes between the coated phase and buffer was similar to that in the liposome/water system. The DPPC column can be used in screening studies to predict the binding properties of drugs onto lipid membranes. PMID:11816013

Kamimori, Hiroshi; Konishi, Masaharu

2002-02-01

381

Pilot scale benzene stripping column testing: Review of test data and application to the ITP columns  

SciTech Connect

Radioactive cesium will be removed from aqueous high level waste (HLW) solutions by precipitation with sodium tetraphenyl borate (TPB) in the In-Tank Precipitation (ITP) process. Benzene is generated due to the radiolysis of TPB, and dissolves into the decontaminated salt solution (DSS) and into the water used to wash (WW) the precipitate. These solutions will be processed through stripping columns to reduce the benzene concentration to satisfy limits for disposal of the DSS and for temporary storage of the WW. A pilot scale testing program to evaluate the stripping column operation in support of ITP startup activities has been completed. Equipment and test plans were developed so that data obtained from the pilot scale testing would be directly applicable to full scale column operation and could be used to project hydraulic performance and stripping efficiency of both columns. A review of the test data indicate that the ITP stripping columns will be capable of reducing benzene concentrations in salt solutions to satisfy Saltstone and Tank 22 acceptance limits. An antifoam (AF) will be required to maintain the column differential pressure below the vendor recommendation of 40 inches wc so that design feed rates can be achieved. Additionally, the testing program indicated that the nitrogen rate can be decreased from the ITP column design rates and still satisfy benzene concentration requirements in the product.

Georgeton, G.K.; Gaughan, T.P.; Taylor, G.A.

1993-09-10

382

The slurry-column coal beneficiation process  

Microsoft Academic Search

The slurry column is a second-generation process developed at the Idaho National Engineering Laboratory (INEL) for the beneficiation of fine (60 mesh × 10 ?m) coal by a combination of the physical separation of mineral matter and the biooxidation of pyrite. The bioreactor is a slurry-type airlift, specifically designed to allow the large liberated inclusions of pyrite and other insoluble

Graham F. Andrews; Karl S. Noah

1997-01-01

383

Solute transport through large unsaturated soil columns  

Microsoft Academic Search

Scale effects have been observed between solute transport experiments performed in the laboratory and in the field. This study was conducted to quantify differences between laboratory scale (30 cm long) and field scale solute transport using 6 m long soil columns to represent field conditions. Steady-state tritium, bromide, boron and chromium transport parameters determine from effluent breakthrough curves in small

Porro

1989-01-01

384

Continuum Radiation in an Argon Positive Column.  

National Technical Information Service (NTIS)

A weak continuum with a maximum near 3100A is radiated from the positive column of an argon normal-glow discharge. The intensity distribution of this continuum (observed here from 2900 to 7000A) does not correspond to that of a free-free, free-bound recom...

J. F. Prince W. W. Robertson

1966-01-01

385

On Row Rank Equal Column Rank  

ERIC Educational Resources Information Center

We will prove a well-known theorem in Linear Algebra, that is, for any "m x n" matrix the dimension of row space and column space are the same. The proof is based on the subject of "elementary matrices" and "reduced row-echelon" form of a matrix.

Khalili, Parviz

2009-01-01

386

Waffle Slabs Supported on Rows of Columns  

Microsoft Academic Search

By incorporating recent theoretical developments covering plates with eccentric stiffeners, an approximate analysis of reinforced concrete waffle slabs supported on rows of columns is presented. The corner slab panel is treated as a rectangular orthotropic slab supported at its four corners, and its solution can be put in a simple closed form. The exterior panel is taken as a long

Pisidhi Karasudhi; Intarachai Hovichitr; Seng-Lip Lee

1981-01-01

387

Contexts for Column Addition and Subtraction  

ERIC Educational Resources Information Center

In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by designing…

Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

2011-01-01

388

Ionized Columns between Thunderstorms and the Ionosphere  

Microsoft Academic Search

It is shown that, if electrons of relativistic energies are generated within thunder- storms and then 'run away' upward above the thunderclouds, their range is probably only a few kilometers; their ionizing effects are therefore localized. Calculations indicate, however, that the bremsstrahlung produced during the stoppage of the electrons can create ionized columns extending to ionospheric heights (about 100 kin).

R. K. COLE

1966-01-01

389

A numerical case study of packed columns  

Microsoft Academic Search

This paper presents results concerning the validation of a recently developed packing algorithm. The basic ethos of this algorithm, known as DigiPac, is to use three-dimensional methods to digitise particle shapes, and to use this digital information directly in computations of how particles pack together without further conversion or the need for modelling. A variety of simulations of packed columns,

R. Caulkin; M. Fairweather; X. Jia; R. A. Williams

2005-01-01

390

Capacity of Columns with Splice Imperfections.  

National Technical Information Service (NTIS)

The milled or cut surfaces at column splices as a general rule do not make a perfect full and even contact. Recognizing this fact, the AISC Code of Standard Practice accepts a maximum gap of 1/16 inc. at the faying surfaces. Data on the behavior of such i...

E. P. Popov R. M. Stephen R. Philbrick

1976-01-01

391

Density Gradient Columns for Chemical Displays.  

ERIC Educational Resources Information Center

Procedures for preparing density gradient columns for chemical displays are presented. They include displays illustrating acid-base reactions, metal ion equilibria, and liquid density. The lifetime of these metastable displays is surprising, some lasting for months in display cabinets. (JN)

Guenther, William B.

1986-01-01

392

[Spondylosis: diseases of the vertebral column].  

PubMed

Frequent and transcendent diseases for the difficulties of his diagnosis and treatment. The components of the vertebral column, vertebral bodies, discs and unvertebral joints, spondylosis ligaments must be considered to be a functional Unit. The Patology of each one of their parts concerns or reverberates in others. PMID:18924356

Pérez, Amador Schüller

2008-01-01

393

The Energy-Absorbing Steering Column.  

National Technical Information Service (NTIS)

A previous four-year study of fatal automobile accidents has shown that the steering assembly-the column and steering wheel rim--ranked high as one of the major causes of fatzal and serious injuries to drivers in automobile crashes. These studies indicate...

D. F. Huelke W. A. Chewning

1968-01-01

394

Extendible column can be stowed on drum  

NASA Technical Reports Server (NTRS)

Column formed from a series of segments held together by an internal spring or cable can be coiled on a drum or extended into a rigid structure. This storable coil is useful in boring for soil samples and supporting electrical and optical sensors.

Holtz, G. M.; Howard, E. A.

1965-01-01

395

Discrete Element Simulation of Granular Column Collapse  

NASA Astrophysics Data System (ADS)

Many natural hazards and industrial processes involve the collapse of granular particles onto a horizontal plane. Recent researches have studied the fundamental physics of the collapse of granular columns in experimental and numerical approaches. This paper presents a three-dimensional discrete element simulation of the axisymmetric spreading of initially vertical granular columns, in which the runout of the grains and their dynamic motion are continuously monitored during the course of collapse. Using a polar coordinate method to quantify the spread of the grains, the numerical results are in good agreement with previous research findings. The collapse dynamics is shown to be dependent on the initial geometry of the cylindrical column and independent of the inter-granular friction. Two distinct flow regimes are observed: a linear scaling and a power-law scaling are derived for the final runout distances of the columns. The problem is further explored by studying the effects of coefficient of restitution on the runout mechanics, in which energy dissipation at collisions has played an important role in determining the runout of the system.

Lo, Chi Yan; Bolton, Malcolm; Cheng, Yi Pik

2009-06-01

396

WATER COLUMN DATA AND SPECTRAL IRRADIANCE MODEL  

EPA Science Inventory

Water samples collected monthly, for 18 months, from six sites in the Laguna Madre were analyzed to identify and quantify phytopigments using High Performance Liquid Chromatography (HPLC). In addition, water column pigment and nutrient data were acquired at 12 stations in Upper ...

397

Synthesis and applications of monolithic HPLC columns  

NASA Astrophysics Data System (ADS)

Silica and carbon monolithic columns were synthesized and modified for liquid chromatography applications. Column configurations and cladding techniques were investigated in detail. Three novel approaches have been developed for the synthesis of bimodal porous rods. Out of these three methods, gel-casting was adopted for the synthesis of silica monoliths with ordered mesopores and uniform macropores; the use of colloidal templates and dual phase separation has been successfully implemented for the synthesis of carbon monoliths with well-controlled meso- and macro- porosities. The formation of mesopores in carbon materials has been further studied in the microphase separation of block copolymers. Electrochemical modification of carbon monoliths was discovered to be an efficient method for converting covalently bonded functionalities to carbon monoliths. N,N'-diethylaminobenzene has been attached to carbon surface for the separation of proteins and protein digests. The performances of carbon-based monolithic columns were studied intensely through frontal analysis and Van Deemter plot. Temperature and pressure effects were also investigated in carbon-based columns. The density of bonding on the modified carbon monoliths was characterized by thermogravimetric analysis.

Liang, Chengdu

398

A method for determining the column curve from tests of columns with equal restraints against rotation on the ends  

NASA Technical Reports Server (NTRS)

The results are presented of a theoretical study for the determination of the column curve from tests of column specimens having ends equally restrained against rotation. The theory of this problem is studied and a curve is shown relating the fixity coefficient c to the critical load, the length of the column, and the magnitude of the elastic restraint. A method of using this curve for the determination of the column curve for columns with pin ends from tests of columns with elastically restrained ends is presented. The results of the method as applied to a series of tests on thin-strip columns of stainless steel are also given.

Lundquist, Eugene E; Rossman, Carl A; Houbolt, John C

1943-01-01

399

Dynamics experimental study of column in the well  

NASA Astrophysics Data System (ADS)

Mechanical analysis of bottom hole assembly(BHA) is the basis of well trajectory control technology. Considering the displacement and force boundary conditions of drillstring and testing axial excitation force of bottom column, axial acceleration of head column, transverse displacement of columns and collision and contact forces between inner columns and outer pipe, dynamics experimental device of column-liquid interaction is built to do two kinds of test: the column vibrating test under the conditions of different vibrating frequency and different axial excitation force and the column rotating test under the conditions of different axial excitation force, different rotating speed and different flux. The experimental results show that the changes of vibrating frequency and the flow has little effect on axial vibrating force of bottom column and radial displacement of column, but the existence of the liquid will reduce the axial force amplitude of bottom column; With the speed increased, radial displacement of the column and the segments of the collision and contact column between the column and the pipe increase and the columns have the phenomenon of multi-segments swing. It is to provide the device and means to study dynamics movement rules of rotating column in the pipeline.

Liu, Jubao; Li, Zhimiao

2009-12-01

400

DNAPL transport through macroporous, clayey till columns  

SciTech Connect

This paper provides the first experimental determination of the rates and distribution of transport of a dense, nonaqueous phase liquid (DNAPL) through a naturally bioporous and fractured clayey till deposit. Until now, assessment of DNAPL behavior in this type of deposit has relied on theoretical studies. Predictions of DNAPL transport have proven to be uncertain as a result of difficulties in measuring critical parameters such as DNAPL entry pressure and flow behavior in response to natural fracture/biopore apertures and the degree of interconnection of these structures. In the present investigation, the migration of free product trichloroethylene (TCE) was studied by means of two undisturbed clayey till columns under in situ effective soil stress conditions. The experiments revealed that transport of TCE was restricted to biopores in one column and fractures in another column, bypassing the low-permeability clayey matrix. Effective porosities of the columns, i.e., biopores and fractures, were two to three orders of magnitude lower than total porosities, i.e., macropores and matrix. Single phase water flow rates through the columns at water-saturated conditions followed a linear relationship with hydraulic gradient. TCE flow could not be predicted from the single-phase calculations because of nonlinearity observed between applied TCE injection heads and resulting TCE flow. TCE flow rates were 24 and 10.3 m/day at TCE gradients of 1.18 and 0.91, respectively. The observed flow rates indicate that in cases where vertical biopores or fractures fully penetrate clayey till aquitards, a low-viscosity DNAPL may quickly enter underlying aquifers. The experiments further indicate that 100 liters of a low-viscosity DNAPL are sufficient to contaminate approximately 25 to 100 m{sup 3} of till material because of the small effective porosity constituted by the biopores and fractures.

Joergensen, P.R. [Univ. of Copenhagen (Denmark). Geological Inst.]|[Danish Geotechnical Inst., Lyngby (Denmark); Broholm, K.; Sonnenborg, T.O.; Arvin, E. [Technical Univ. of Denmark, Lyngby (Denmark)

1998-07-01

401

A CMOS integrated circuit for pulse-shape discrimination  

Microsoft Academic Search

A CMOS integrated circuit (IC) for pulse-shape discrimination (PSD) has been developed. The IC performs discrimination of gamma-rays and neutrons as part of a monitoring system for stored nuclear materials. The method extracts the pulse tail decay time constant using a leading edge trigger for identifying the start of the pulse and a zero-crossing discriminator to determine the zero crossing

S. S. Frank; M. N. Ericson; M. L. Simpson; D. P. Hutchinson; R. A. Todd

1995-01-01

402

PULSED POWER APPLICATIONS IN HIGH INTENSITY PROTON RINGS.  

SciTech Connect

Pulsed power technology has been applied in particle accelerators and storage rings for over four decades. It is most commonly used in injection, extraction, beam manipulation, source, and focusing systems. These systems belong to the class of repetitive pulsed power. In this presentation, we review and discuss the history, present status, and future challenge of pulsed power applications in high intensity proton accelerators and storage rings.

ZHANG, S.Y.; SANDBERG, J.; ET AL.

2005-05-16

403

Sequential blind extraction of instantaneously mixed sources  

Microsoft Academic Search

This paper presents a general approach to sequential blind extraction of instantaneously mixed sources for several major ill-conditioned cases as well as the regular case of full column rank mixing matrices. Four ill-conditioned cases are considered: The mixing matrix is square but singular; the number of sensors is less than that of sources; the number of sensors is larger than

Yuanqing Li; Jun Wang

2002-01-01

404

ANALYSIS OF AQUEOUS EXTRACT OF INONOTUS OBLIQUUS  

Microsoft Academic Search

Water-soluble melanin complexes were extracted with hot water from Inonotus obliquus fungus. They were characterized before and after reaction with diluted hydrochloric acid. The organic components as products of degradation of melanin complexes were separated by column chromatography and analyzed by GC-MS method.

WITOLD MAZURKIEWICZ

2006-01-01

405

Analysis of aqueous extract of Inonotus obliquus.  

PubMed

Water-soluble melanin complexes were extracted with hot water from Inonotus obliquus fungus. They were characterized before and after reaction with diluted hydrochloric acid. The organic components as products of degradation of melanin complexes were separated by column chromatography and analyzed by GC-MS method. PMID:17438866

Mazurkiewicz, Witold

2006-01-01

406

Comparison of Two Major Classes of Coherent Pulsed Radar Systems  

Microsoft Academic Search

Two classes of coherent radar types are analyzed to ascertain whether any significant advantages exist for a given system. The classes compared are those coherent radars which transmit a phasecoherent pulse-to-pulse RF carrier as opposed to those which transmit randomly phased RF carriers but store the coherent information at the radar for Doppler extraction. Rigorous new analytical development is avoided

Gary Jordan

1975-01-01

407

Nonlinear transmission line (NLTL) design as a pulse generator  

Microsoft Academic Search

Computer simulations are performed to optimize the number of sections in a tapered NLTL generating a pulse signal. The Schottky diode model is used based on physical simulation using Silvaco. The extracted CV characteristics are fitted to a hyperbolic function. The effect of the input frequency on the output pulse is investigated

D. Salamh; D. Linton

1996-01-01

408

Monitoring Abundance and Expression of "Dehalococcoides" Species Chloroethene-Reductive Dehalogenases in a Tetrachloroethene-Dechlorinating Flow Column? †  

PubMed Central

We investigated the distribution and activity of chloroethene-degrading microorganisms and associated functional genes during reductive dehalogenation of tetrachloroethene to ethene in a laboratory continuous-flow column. Using real-time PCR, we quantified “Dehalococcoides” species 16S rRNA and chloroethene-reductive dehalogenase (RDase) genes (pceA, tceA, vcrA, and bvcA) in nucleic acid extracts from different sections of the column. Dehalococcoides 16S rRNA gene copies were highest at the inflow port [(3.6 ± 0.6) × 106 (mean ± standard deviation) per gram soil] where the electron donor and acceptor were introduced into the column. The highest transcript numbers for tceA, vcrA, and bvcA were detected 5 to 10 cm from the column inflow. bvcA was the most highly expressed of all RDase genes and the only vinyl chloride reductase-encoding transcript detectable close to the column outflow. Interestingly, no expression of pceA was detected in the column, despite the presence of the genes in the microbial community throughout the column. By comparing the 16S rRNA gene copy numbers to the sum of all four RDase genes, we found that 50% of the Dehalococcoides population in the first part of the column did not contain either one of the known chloroethene RDase genes. Analysis of 16S rRNA gene clone libraries from both ends of the flow column revealed a microbial community dominated by members of Firmicutes and Actinobacteria. Higher clone sequence diversity was observed near the column outflow. The results presented have implications for our understanding of the ecophysiology of reductively dehalogenating Dehalococcoides spp. and their role in bioremediation of chloroethenes.

Behrens, Sebastian; Azizian, Mohammad F.; McMurdie, Paul J.; Sabalowsky, Andrew; Dolan, Mark E.; Semprini, Lew; Spormann, Alfred M.

2008-01-01

409

Magnetic pulsed septa for the synchrotron 'Pakhra'  

Microsoft Academic Search

Slow extraction system of the Synchrotron 'Pakhra' contains two pulsed septum magnets. They are located inside the synchrotron vacuum chamber. Both the soft and the hard septum magnets have similar mechanical construction. They consist of four magnetic blocks split by three copper brackets. The dimensions of the magnetic gap are 1.2 cm height and 3.6 cm width. The soft septum

Yu. A. Bashmakov; V. A. Karpov

1994-01-01

410

Magnetic pulsed septa for the synchrotron “Pakhra”  

Microsoft Academic Search

Slow extraction system of the Synchrotron “Pakhra” contains two pulsed septum magnets. They are located inside the synchrotron vacuum chamber. Both the soft and the hard septum magnets have similar mechanical construction. They consist of four magnetic blocks split by three copper brackets. The dimensions of the magnetic gap are 1.2 cm height and 3.6 cm width. The soft septum

Yu. A. Bashmakov; V. A. Karpov

1994-01-01

411

?-Linolenic acid purification from seed oil sources by argentated silica gel chromatography column  

Microsoft Academic Search

The polyunsaturated fatty acid ?-linolenic acid (GLA,18:3?6), which has several pharmaceutical properties, has been purified from the seed oil of three plant species, Anchusa azurea, Scrophularia sciophila and Echium fastuosum. The process consists of four main steps, (i) simultaneous extraction and saponification of the seeds; (ii) urea fractionation method; (iii) urea-concentrate methylation; (iv) argentated silica gel column chromatography of the

J. L Guil-Guerrero; El-Hassan Belarbi

2000-01-01

412

Application of Molecularly Imprinted Column for Separation and Purification of Bioactive Compound from Cirsium segetum Bunge  

Microsoft Academic Search

Direct application of monolithic column of molecularly imprinted polymers (MIPs) for selective separation and purification of protocatechuic acid from the crude extract of seeds of Cirsium segetum Bunge was attempted in present work. An in-situ polymerization technique was used for the preparation of MIPs monolith using protocatechuic acid as the template, acrylamide as functional monomer, 1,1,1-Trimethylolpropane trimethacrylate (TRIM) as cross-linker,

Hui Li; Lihua Nie; Yanan Li; Zhaohui Zhang; Hui Shi; Wenbin Hu; Yongkang Zhang

2009-01-01

413

LC-UV Column-Switching for Quantitation of Vitamin K 1 in Infant Formula  

Microsoft Academic Search

This study was undertaken in order to develop an analytical method for vitamin K1 in infant formula. The content of vitamin K1 was investigated by using a column-switching LC-UV method. A Certified Reference Material sample of infant formula containing\\u000a 0.94 ± 0.04 mg kg?1 of vitamin K1 was extracted with hexane followed by enzymatic digestion of fat and precipitation of the fatty acids. The

Jinhyouk Ko; Byung-Man Kwak; Jang-Hyuk Ahn; Seung-Hwan Jeong; Sung-Lye Shim; Kyong-Su Kim; Taehyung Yoon; Leem Dong-gil; Jayoung Jeong

2010-01-01

414

Pulsed pyroelectric crystal-powered gamma source  

SciTech Connect

A compact pulsed gamma generator is being developed to replace radiological sources used in commercial, industrial and medical applications. Mono-energetic gammas are produced in the 0.4 - 1.0 MeV energy range using nuclear reactions such as {sup 9}Be(d,n{gamma}){sup 10}B. The gamma generator employs an RF-driven inductively coupled plasma ion source to produce deuterium ion current densities up to 2 mA/mm{sup 2} and ampere-level current pulses can be attained by utilizing an array extraction grid. The extracted deuterium ions are accelerated to approximately 300 keV via a compact stacked pyroelectric crystal system and then bombard the beryllium target to generate gammas. The resulting microsecond pulse of gammas is equivalent to a radiological source with curie-level activity.

Chen, A. X.; Antolak, A. J.; Leung, K.-N.; Raber, T. N.; Morse, D. H. [Sandia National Laboratories, Livermore, CA 94550 (United States)

2013-04-19

415

Pulsed pyroelectric crystal-powered gamma source  

NASA Astrophysics Data System (ADS)

A compact pulsed gamma generator is being developed to replace radiological sources used in commercial, industrial and medical applications. Mono-energetic gammas are produced in the 0.4 - 1.0 MeV energy range using nuclear reactions such as 9Be(d,n?)10B. The gamma generator employs an RF-driven inductively coupled plasma ion source to produce deuterium ion current densities up to 2 mA/mm2 and ampere-level current pulses can be attained by utilizing an array extraction grid. The extracted deuterium ions are accelerated to approximately 300 keV via a compact stacked pyroelectric crystal system and then bombard the beryllium target to generate gammas. The resulting microsecond pulse of gammas is equivalent to a radiological source with curie-level activity.

Chen, A. X.; Antolak, A. J.; Leung, K.-N.; Raber, T. N.; Morse, D. H.

2013-04-01

416

Securing mechanism for the deployable column of the Hoop/Column antenna  

NASA Technical Reports Server (NTRS)

The Column Longeron Latch (CLL) was designed and developed as the securing mechanism for the deployable, telescoping column of the Hoop/Column antenna. The column is an open lattice structure with three longerons as the principal load-bearing members. It is divided into telescoping sections that are deployed after the antenna is place in Earth orbit. The CLL provides a means to automatically lock the longeron sections into position during deployment as well as a means of unlocking the sections when the antenna is to be restowed. The CLL is a four bar linkage mechanism using the over center principle for locking. It utilizes the relative movement of the longeron sections to activate the mechanism during antenna deployment and restowing. The CLL design is one of the first mechanisms developed to meet the restowing requirements of spacecraft which will utilize the STS retrieval capability.

Ahl, E. L., Jr.

1983-01-01

417

ON THE ORIGIN OF THE HIGH COLUMN DENSITY TURNOVER IN THE H I COLUMN DENSITY DISTRIBUTION  

SciTech Connect

We study the high column density regime of the H I column density distribution function and argue that there are two distinct features: a turnover at N{sub H{sub I}} Almost-Equal-To 10{sup 21} cm{sup -2}, which is present at both z = 0 and z Almost-Equal-To 3, and a lack of systems above N{sub H{sub I}} Almost-Equal-To 10{sup 22} cm{sup -2} at z = 0. Using observations of the column density distribution, we argue that the H I-H{sub 2} transition does not cause the turnover at N{sub H{sub I}} Almost-Equal-To 10{sup 21} cm{sup -2} but can plausibly explain the turnover at N{sub H{sub I}} {approx}> 10{sup 22} cm{sup -2}. We compute the H I column density distribution of individual galaxies in the THINGS sample and show that the turnover column density depends only weakly on metallicity. Furthermore, we show that the column density distribution of galaxies, corrected for inclination, is insensitive to the resolution of the H I map or to averaging in radial shells. Our results indicate that the similarity of H I column density distributions at z = 3 and 0 is due to the similarity of the maximum H I surface densities of high-z and low-z disks, set presumably by universal processes that shape properties of the gaseous disks of galaxies. Using fully cosmological simulations, we explore other candidate physical mechanisms that could produce a turnover in the column density distribution. We show that while turbulence within giant molecular clouds cannot affect the damped Ly{alpha} column density distribution, stellar feedback can affect it significantly if the feedback is sufficiently effective in removing gas from the central 2-3 kpc of high-redshift galaxies. Finally, we argue that it is meaningful to compare column densities averaged over {approx} kpc scales with those estimated from quasar spectra that probe sub-pc scales due to the steep power spectrum of H I column density fluctuations observed in nearby galaxies.

Erkal, Denis [Department of Physics, University of Chicago, Chicago, IL 60637 (United States); Gnedin, Nickolay Y. [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Kravtsov, Andrey V. [Kavli Institute for Cosmological Physics and Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)

2012-12-10

418

Design procedures for fiber composite structural components: Rods, columns and beam columns  

NASA Technical Reports Server (NTRS)

Step by step procedures are described which are used to design structural components (rods, columns, and beam columns) subjected to steady state mechanical loads and hydrothermal environments. Illustrative examples are presented for structural components designed for static tensile and compressive loads, and fatigue as well as for moisture and temperature effects. Each example is set up as a sample design illustrating the detailed steps that are used to design similar components.

Chamis, C. C.

1983-01-01

419

High-performance liquid chromatographic assay of zonisamide in human plasma using a non-porous silica column.  

PubMed

A new method for measuring zonisamide (ZNS) in plasma by high-performance liquid chromatography was developed by using a 2-microm reversed-phase non-porous silica column. ZNS in plasma was first purified with a column extraction technique and injected onto the non-porous silica column. Calibration curve was linear over the concentration range of 1-80 microg/ml in plasma. The recoveries of ZNS added to plasma were more than 95.4% with the coefficient of variation less than 9.0%. We developed a rapid routine method using the non-porous silica column that was accurate and improved solvent consumption in the measurement of ZNS. PMID:11393722

Nakamura, M; Hirade, K; Sugiyama, T; Katagiri, Y

2001-05-01

420

Evaluation of throughput improvement and character projection in multi-column-cell E-beam exposure system  

NASA Astrophysics Data System (ADS)

In the Mask D2I project at ASET, the authors evaluated an e-beam multi column cell exposure system with character projection to expose photomask patterns of 65nm and 45nm node logic devices with OPC corrections. They prepared more than 2,000 characters in a deflection area of a character projection mask extracted from the 65nm node logic device pattern. The character projection in the multi column cell system could expose patterns equivalent to those by the conventional variable shaped beams. In a typical pattern layout of photomasks of 45nm node logic devices, the four column cell system required the exposure time of about 1/3 of the time required by a single column system. The character projection could reduce the exposure time corresponding to the reduction of shot counts. The pattern priorities also reduced the exposure time as the result of shot count reduction and minimizing wait time for deflection settling.

Yamada, Akio; Oae, Yoshihisa; Okawa, Tatsuro; Takizawa, Masahiro; Yamabe, Masaki

2010-04-01

421

Polonium-210 Assay Using a Background-Rejecting Extractive Liquid-Scintillation Method.  

National Technical Information Service (NTIS)

This paper describes a procedure which combines solvent extraction with alpha liquid scintillation spectrometry. Pulse shape discrimination electronics are used to reject beta and gamma pulses and to lower the background count to acceptable levels. Concen...

C. N. Case, W. J. McDowell

1981-01-01

422

Purification of lignans from Schisandra chinensis fruit by using column fractionation and supercritical antisolvent precipitation.  

PubMed

This study examined the use of ultrasonic-assisted extraction (UAE) coupled with column chromatography (CC) and supercritical antisolvent (SAS) precipitation in purifying five lignans from the dried fruit of Schisandra chinensis. Column fractionation of the ultrasonic extracts and SAS precipitation of the column elution resulted in a ten- and three-fold increase of the five lignans, respectively. Experimental data showed that the concentrations of the five lignans increased from 26.14mgg(-1) in the extraction to 581.85mgg(-1) in the effluent after SAS precipitation with a recovery of 84%. The effluent contained 145.32mgg(-1)of schisandrol B, 56.65mgg(-1)of schisandrin A, 66.38mgg(-1) of ?-schisandrin, 266.70mgg(-1) of gomisin N, and 46.80mgg(-1)of schisandrin C. In addition, our experimental results from a response surface method designed SAS precipitations for the enhancement of the purity of the five lignans, showed that time and carbon dioxide flow rate are significant in altering the purity and the recovery. This work demonstrated that the five lignans of Schisandra chinensis were successfully purified by using the SAS process. PMID:23415446

Huang, Tai-Ling; Lin, Justin Chun-Te; Chyau, Charng-Cherng; Lin, Kuo-Li; Chang, Chieh-Ming J

2013-03-22

423

Extraction and purification of total RNA from Streptococcus mutans biofilms.  

PubMed

RNA isolation from Streptococcus mutans within biofilms is challenging because of the presence of extracellular polysaccharide matrix that interferes with RNA extraction procedures. In an effort to solve this difficult problem, we examined several protocols to extract and purify RNA from S. mutans biofilms. A combination of sonication (three times using a 30-s pulse at 7 W) with washing in phosphate-buffered saline removed most of the extracellular polysaccharides from the biofilms and provided the highest RNA yield. Further homogenization-mechanical cells disruption in NAES buffer (50 mM sodium acetate buffer, 10 mM EDTA, and 1% SDS, pH 5.0) and acid phenol/chloroform yielded 547.2+/-23.4 microg RNA/100 mg of biofilm dry weight. An additional acid phenol/chloroform extraction further improved the purification of RNA without significantly affecting the RNA yield. The combination of DNase I in silica gel-based column and recombinant DNase I in solution effectively removed the genomic DNA as determined by real-time quantitative reverse transcriptase PCR (RT-PCR), resulting in 92.0+/-0.6 microg of purified RNA per 100 mg of biofilm dry weight. The complementary DNAs generated from the purified RNA sample were efficiently amplified using gtfB S. mutans-specific primers. The results demonstrated a method that yields high-quality RNA from biofilms of S. mutans in sufficient quantity for real-time RT-PCR analyses, and our data have relevance for isolation of RNA from other biofilm-forming microorganisms. PMID:17475197

Cury, Jaime A; Koo, Hyun

2007-06-15

424

Extraction and quantitation of astaxanthin from Phaffia rhodozyma  

Microsoft Academic Search

The rapid, quantitative release of astaxanthin and other carotenoids from the yeast Phaffiarhodozyma is described. Hashed cells are ruptured with dimethylsulfoxide (DMSO) and carotenoids extracted into an organic solvent. Extraction and spectrophotometric quantitation of total carotenoids is rapid, reproducible and only small volumes (0.1–2 ml) of culture are required. HPLC analysis in normal phase silica gel column indicates that astaxanthin

J. James Sedmak; Deepthi K. Weerasinghe; Setsuko O. Jolly

1990-01-01

425

Extraction, Purification, and Spectroscopic Characterization of a Mixture of Capsaicinoids  

ERIC Educational Resources Information Center

This laboratory experiment provides a safe and effective way to instruct undergraduate organic chemistry students about natural-product extraction, purification, and NMR spectroscopic characterization. On the first day, students extract dried habanero peppers with toluene, perform a pipet silica gel column to separate carotenoids from…

Wagner, Carl E.; Cahill, Thomas M.; Marshall, Pamela A.

2011-01-01

426

Effects of Gravity on Cocurrent Two-Phase Gas-Liquid Flows Through Packed Columns  

NASA Technical Reports Server (NTRS)

This work presents the experimental results of research on the influence of gravity on flow pattern transitions, pressure drop and flow characteristics for cocurrent gas-liquid two-phase flow through packed columns. The flow pattern transition data indicates that the pulse flow regime exists over a wider range of gas and liquid flow rates under reduced gravity conditions compared to normal gravity cocurrent down-flow. This is illustrated by comparing the flow regime transitions found in reduced gravity with the transitions predicted by Talmor. Next, the effect of gravity on the total pressure drop in a packed column is shown to depend on the flow regime. The difference is roughly equivalent to the liquid static head for bubbly flow but begins to decrease at the onset of pulse flow. As the spray flow regime is approached by increasing the gas to liquid ratio, the effect of gravity on pressure drop becomes negligible. Finally, gravity tends to suppress the amplitude of each pressure pulse. An example of this phenomenon is presented.

Motil, Brian J.; Balakotaiah, Vemuri; Kamotani, Yasuhiro

2001-01-01

427

A pulsed positron beam for positronium spectroscopy  

SciTech Connect

A laboratory-based pulsed positron beam that will be employed in an n=2 positronium spectroscopy experiment has been fully developed and tested. Moderated positrons from a radioactive source are accumulated in a cylindrical Penning trap with a slowly-ramped electric potential applied to the source assembly. The accumulation efficiency is found to be 10-45% for repetition rates of 100 - 670 Hz yielding positron pulse widths of {approximately} 25 ns (FWHM). The accumulation process, however, increases the transverse velocity of the beam which consequently raises the background-positron noise in the spectroscopy experiment. Furthermore, the precision of this measurement greatly suffers if conducted in a large magnetic field. Therefore, the pulsed beam is extracted to a magnetic-field-free region, focused, and remoderated using a Ni crystal. This remoderated pulsed beam is subsequently focused on to a < 2 mm diameter (FWHM) spot with a combined remoderation and transport efficiency of {approximately} 13%.

Ghaffari, B.; Conti, R.S.; Gidley, D.W.; Steiger, T.D.

1996-05-01

428

Modeling of Crystalline Silicotitanate Ion Exchange Columns  

SciTech Connect

Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R. G. Anthony, Department of Chemical Engineering, Texas A&038;M University, and Professor S. W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports.

Walker, D.D.

1999-03-09

429

Solar Cycle Variability in Tropical Column Ozone  

NASA Astrophysics Data System (ADS)

Using an empirical orthogonal function (EOF) method [Camp et al., 2003], we analyzed the Merged Ozone Data (MOD) set from late 1978 to the present. The decadal variability of column ozone in the tropics follows that of the sun over three solar cycles. The peak-to-peak amplitude is about 10 DU (Dobson Units), consistent with the conclusion of Camp et al. [2003], who analyzed the MOD data up to and including 2000. Previous attempts to model the amplitude of the observed solar cycle in ozone were unsuccessful, as models tended to underestimate the solar cycle effect. Using the Whole Atmosphere Community Climate Model (WACCM) in combination with the latest satellite measurements of solar variability in the UV [McClintock et al., 2005; Harder et al., 2009], we correctly simulate the solar cycle signal in the total column ozone for the first time. The implications for solar forcing on middle atmosphere chemistry are discussed.

Yung, Y. L.; Liang, M.; Li, K.; Jiang, X.; Camp, C. D.

2011-12-01

430

Assembly procedure for column cutting platform  

SciTech Connect

This supporting document describes the assembly procedure for the Column Cutting Platform and Elevation Support. The Column Cutting Platform is a component of the 241-SY-101 Equipment Removal System. It is set up on the deck of the Strongback Trailer to provide work access to cut off the upper portion of the Mitigation Pump Assembly (MPA). The Elevation Support provides support for the front of the Storage Container with the Strongback at an inclined position. The upper portion of the MPA must be cut off to install the Containment Caps on the Storage Container. The storage Container must be maintained in an inclined position until the Containment Caps are installed to prevent any residual liquids from migrating forward in the Storage Container.

Routh, R.D.

1995-04-01

431

Algae columns with anodic stripping voltammetric detection  

SciTech Connect

The use of silica-immobilized algal cells for on-line column separation in conjunction with continuous monitoring of trace metals is described. Algae-silica preparations are highly suitable for flow analysis as they couple the unique reactivity patterns and high binding capacity of algal biomass with the hydrodynamic and mechanical features of porous silica. Such advantages are illustrated by using on-line anodic stripping voltammetry and the alga Chlorella pyrenidosa. Selective and exhaustive removal of interfering constituents circumvents common problems such as overlapping peaks and intermetallic effects. Effects of flow rate, pH, operation time, and other variables are reported. The system is characterized by high durability, simplicity, and economy and offers an attractive alternative to prevalent columns used for flow analysis.

Kubiak, W.W.; Wang, J.; Darnall, D.

1989-03-01

432

SNS EXTRACTION FAST KICKER SYSTEM DEVELOPMENT.  

SciTech Connect

The SNS Extraction Fast Kicker System is a very high power, high repetition rate pulsed power system. It was design and developed at Brookhaven National Laboratory. This system will consist of fourteen identical high voltage, high current modulators, and their auxiliary control and charging systems. The modulators will drive fourteen extraction magnet sections located inside of the SNS accumulator ring. The required kicker field rise time is 200 ns, a pulse flattop of 700 ns, a pulse repetition rate of 60 pulse-per-second. A 2500 Ampere per modulator output is required to reach the extraction kicker magnetic field strength. This design features a Blumlein Pulse-Forming-Network based topology, a low beam impedance termination, a fast current switching thyratron, and low inductance capacitor banks. It has a maximum charging voltage of 50kV, an open circuit output of 100kV, and a designed maximum pulsed current output of 4kA per modulator. The overall system output will be multiple GVA with 60 Pulse-per-second repetition rate. A prototype modulator has been successfully built and tested well above the SNS requirement. The modulator system production is in progress.

ZHANG,W.; SANDBERG,J.; LAMBIASE,R.; LEE,Y.Y.; LOCKEY,R.; MI,J.; NEHRING,T.; PAI,C.; TSOUPAS,N.; TUOZZOLO,J.; WARBURTON,D.; WEI,J.; RUST,K.; CUTLER,R.