These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

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

2

Study on the dynamic holdup distribution of the pulsed extraction column  

SciTech Connect

In the study, a CSTR cascade dynamic hydraulic model was developed to investigate the dynamic holdup distribution of the pulsed extraction column. It is assumed that the dynamic process of the dispersed phase holdup of pulsed extraction column has equal effects with the operational process of multiple cascade CSTRs. The process is consistent with the following assumptions: the holdups vary on different stages but maintain uniform on each stage; the changes of the hydraulic parameters have impact initially on the inlet of dispersed phase, and stability will be reached gradually through stage-by-stage blending. The model was tested and verified utilizing time domain response curves of the average holdup. Nearly 150 experiments were carried out with different capillary columns, various feed liquids, and diverse continuous phases and under different operation conditions. The regression curves developed by the model show a good consistency with the experimental results. After linking parameters of the model with operational conditions, the study further found that the parameters are only linearly correlated with pulse conditions and have nothing to do with flow rate for a specific pulsed extraction column. The accuracy of the model is measured by the average holdup, and the absolute error is ±0.01. The model can provide supports for the boundary studies on hydraulics and mass transfer by making simple and reliable prediction of the dynamic holdup distribution, with relatively less accessible hydraulic experimental data. (authors)

Wang, S.; Chen, J.; Wu, Q. [Tsinghua University, Beijing 100084 (China)

2013-07-01

3

PULSE COLUMN DESIGN  

Microsoft Academic Search

A stagewise approach was used in a theoretical analysis of pulse columns. ;\\u000a In the analysis the column was arbitrarily divided into discrete stages ;\\u000a comprising that part of the column between two adjacent perforated plates. The ;\\u000a operation of the pulse column was described mathematically using material balance ;\\u000a equations, and a design method was derived which used two

L. E. Burkhart; R. W. Fahien

1958-01-01

4

Radiotracer investigations to study the hydrodynamic characteristics of continuous phase in a pulsed sieve plate extraction column  

NASA Astrophysics Data System (ADS)

The present investigations are focused to study the hydrodynamic characteristics of continuous phase in a pulsed sieve plate extraction column using 68Ga in the form of gallium chloride from an industrial radionuclide generator (68Ge/68Ga). Labeling of water with the subject radiotracer in water-kerosene environment was evaluated. Experiments for Residence Time Distribution (RTD) analysis were carried out for a range of dispersed phase superficial velocities in a liquid-liquid extraction pulsed sieve plate column operating in the emulsion regime with water as continuous and kerosene as dispersed phase. Axial Dispersion Model (ADM) was used to simulate the hydrodynamic characteristics of continuous phase. It has been observed that the axial mixing in the continuous phase decreases and slip velocity increases with increase in superficial velocity of dispersed phase while the holdup of continuous phase was found to decrease with increase in superficial velocity of dispersed phase. ADM with open-open boundary condition was found to be a suitable model for the subject system.

Din, G. U.; Khan, I. H.; Chughtai, I. R.; Inayat, M. H.; Jin, J. H.

2013-05-01

5

Installation of the Pulse-Plate Column Pilot Plant  

SciTech Connect

There are three primary types of solvent extraction equipment utilized in the nuclear industry for reprocessing of used nuclear fuel; pulse columns, mixer-settlers, and centrifugal contactors. Considerable research and development has been performed at the INL and throughout the DOE complex on the application of centrifugal contactors for used fuel reprocessing and these contactors offer many significant advantages. However, pulse columns have been used extensively in the past in throughout the world for aqueous separations processes and remain the preferred equipment by many commercial entities. Therefore, a pulse-plate column pilot plant has been assembled as part of the Advanced Fuel Cycle Initiative to support experimentation and demonstration of pulse column operation. This will allow the training of personnel in the operation of pulse columns. Also, this capability will provide the equipment to allow for research to be conducted in the operation of pulse columns with advanced solvents and processes developed as part of the fuel cycle research and development being performed in the AFCI program.

Nick R. Mann

2009-07-01

6

Experimental study of axial temperature profile characteristics in a Purex process pulsed column  

Microsoft Academic Search

Axial temperature profiles were measured in an experimental pulsed column of the type conventionally used in nuclear spent fuel commercial reprocessing plants by injecting hot water at various column heights to simulate the uranium extraction heat. The effects of the flow and heating conditions were estimated and the obtained data were analyzed by a developed calculation code. The effects of

T. Tsukada; K. Takahashi

1994-01-01

7

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

8

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

9

Evaluation of Packed Columns in Supercritical Extraction Processes  

E-print Network

--------- EVALUATION OF PACKED COLUMNS IN SUPERCRITICAL EXTRACTION PROCESSES Paul J. Rathkamp, James R. Fair, Jimmy L. Humphrey The University of Texas at Austin Austin, Texas ABSTRACT The purpose of the present work is to add to the base...). From a process point of view conventional liquid-liquid and supercritical fluid extraction (SFE) are identical in that one or more components of a liquid solution are separated by contact with a second immiscible liquid called the solvent...

Rathkamp, P. J.; Fair, J. R.; Humphrey, J. L.

10

COLUMN VAPOR EXTRACTION 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. ir is pumped from the contaminated area and the chemicals are removed from the resulting vapor stream. n this work laboratory, soil column experiments were conduct...

11

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

12

Extraction of 15 microcystins and nodularin using immunoaffinity columns.  

PubMed

Microcystins (MCYSTs) were isolated from surface water using reusable immunoaffinity columns. Individual MCYST were determined by high performance liquid chromatography equipped with a photo-diode array detector (HPLC-PDA, 200-300 nm). Subsequent analysis of the samples by liquid chromatography-electrospray ionization mass spectrometry (LC-ESMS) provided molecular weight information, which was used to tentatively identify individual MCYST variants for which standards were not available. Results obtained using immunoaffinity columns (IAC)-HPLC-PDA were compared to those obtained using solid phase extraction (SPE) Oasis HLB-HPLC-PDA. This is the first report of the extraction of 15 microcystins and nodularin using immunoaffinity columns. Whereas previous reports demonstrates the use of IAC for four microcystins, we found that IAC selectively extracted the following microcystins: MCYST-RR, [D-Asp3]MCYST-RR, MCYST-YR, MCYST-LR, 3 MCYST-LR variants, MCYST-AR, MCYST-FR, MCYST-WR, MCYST-LA, MCYST-LA variant, the less polar microcystins such as MCYST-LF, MCYST-LW and nodularin. The IAC extracts were free of interferences which enabled better detection and identification of MCYSTs. Based on the amount loaded to the cartridges, the method detection limit was 10-14 ng when using IAC and 25 ng for SPE of each MCYST-RR, MCYST-YR and MCYST-LR. Reproducibilities expressed as relative standard deviation were 6-10% for SPE and 4-17% for IAC. PMID:14602114

Aranda-Rodriguez, Rocio; Kubwabo, Cariton; Benoit, Frank M

2003-11-01

13

Rapid Column Extraction method for SoilRapid Column Extraction method for Soil  

SciTech Connect

The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu) neptunium (Np), uranium (U), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha spectrometry. The method combines a rapid fusion step for total dissolution to dissolve refractory analytes and matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

Maxwell, Sherrod, L. III; Culligan, Brian K.

2005-11-07

14

Design of extraction column methanol recovery system for the TAME reactive distillation process  

Microsoft Academic Search

This paper studies the synthesis and the design of methanol recovery system for TAME reactive distillation process using extraction column with water as a solvent. The design of the extraction column system has not been studied in the literature. The effect of operating conditions such as solvent flowrate, extraction column temperature, and number of equilibrium trays are studied. It is

Muhammad A. Al-Arfaj

2004-01-01

15

Pulsed electromembrane extraction: a new concept of electrically enhanced extraction.  

PubMed

In the present work, pulsed electromembrane extraction (PEME) is introduced for the first time as an efficient and inexpensive method for the extraction of ionizable compounds from different matrices. The setup proposed for electromembrane extraction (EME) provides a very stable system and satisfactory repeatability (RSDs<4.4) in comparison with existing methods. In this paper, PEME is conducted for the extraction of model analytes from biological fluids. The effective parameters such as extraction time, applied voltage and the duration of pulse and outage period are optimized using the experimental design. Preconcentration factors in the range of 100-140 and recoveries in the range of 95-108 were obtained in different biological matrices. The linear dynamic ranges of 5-200 ng mL(-1) (with correlation coefficient higher than 0.9955) and limits of detection of 1.0 ng mL(-1) were obtained for both of the drugs. The figures of merit of PEME were compared with the results from conventional EME, which proves the advantages of the proposed technique. PMID:22999198

Rezazadeh, Maryam; Yamini, Yadollah; Seidi, Shahram; Esrafili, Ali

2012-11-01

16

Rapid Actinide Column Extraction Methods for Bioassay Samples  

SciTech Connect

A new, rapid separation method to assay actinides in urine samples has been developed at the Westinghouse Savannah River Site (SRS). The new method separates plutonium, neptunium, uranium, americium and strontium-90 with high chemical recovery and excellent thorium removal. The method uses calcium phosphate precipitation and stacked TEVA Resin(R) and TRU Resin(R) cartridges to separate and purify the actinides. Plutonium and neptunium are separated on TEVA Resin(R), while uranium and americium are simultaneously retained and separated on TRU Resin(R). Plutonium-236 tracer can be used to allow simultaneous separation and measurement of both plutonium and neptunium using TEVA Resin(R). Strontium-90 can also be separated on Sr Resin(R) by evaporating and redissolving load and rinse solutions collected from the TEVA/TRU column and separating strontium on Sr-Resin(R). Fast flow rates are achieved by using small particle size resin cartridges and a vacuum box separation system that will separate 24 samples at a time. This unique approach can be used with urine samples because iron is not present at significant levels in urine and plutonium reduction is accomplished without adding iron (II) to the sample. The advantage of this approach is that actinides can be loaded onto two separate resins in a single load step with simultaneous extraction and assay of neptunium and plutonium with high chemical recovery and excellent removal of matrix interferences.

Maxwell, S.L.

2003-01-14

17

Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation  

PubMed Central

We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations. PMID:24060831

Eilenberger, Falk; Kabakova, Irina V.; de Sterke, C. Martijn; Eggleton, Benjamin J.; Pertsch, Thomas

2013-01-01

18

Fuzzy Extraction System for Heart Pulse by Air Pressure Sensor  

Microsoft Academic Search

In this paper, we detect a pressure change of vital information and a heart pulse using an air pressure sensor. We could detect the heart pulse at higher S\\/N ratio for the various positions using an air pressure sensor. As the result for live volunteers, we could extract the heart pulse at the 1.28% error ratio. In the temporal transitional

Y. Kamozaki; T. Sawayama; K. Taniguchi; S. Kobashi; K. Kondo; Y. Hata

2006-01-01

19

Extraction of solanesol from tobacco ( Nicotiana tobaccum L.) leaves by bubble column  

Microsoft Academic Search

An extraction method, namely bubble column extraction (BCE), was developed for the rapid and efficient extraction of solanesol from tobacco leaves. Liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) was used for qualitative analysis and the reverse phase high performance liquid chromatography (HPLC) was used for quantification analysis. Several parameters, such as extraction solvent, particle size of sample, extraction time, liquor to material

Chunjian Zhao; Yuangang Zu; Chunying Li

2009-01-01

20

Genomic DNA extraction protocols for bone samples: The comparison of Qiagen and Zymo Research spin columns  

Microsoft Academic Search

The aim of this study was to develop an extraction protocol for bone samples based on ZR Genomic DNA Tissue MicroPrep kit and perform a quantitative comparison with the existing silica extraction protocol based on Qiagen columns and evaluate the effect of demineralization on the quantity of extracted DNA.

Daniel Vanek; Marcela Silerova; Vladislava Urbanova; Lenka Saskova; Jitka Dubska; Michal Beran

21

Enzyme mass-transfer coefficient in aqueous two-phase systems using static mixer extraction column  

Microsoft Academic Search

Recent technical advances in aqueous two-phase systems (ATPS) have made this a sound technique for the extraction of biomacromolecules. The extraction of !-amylase was investigated using aqueous two-phase systems formed by sodium sulphate-polyethylene glycol (PEG) in water in a 47-mm inner diameter spray column packed with three types of static mixers. The effects of dispersed-phase flow rate, phase composition, column

K. Rostami; M. Alamshahi

2002-01-01

22

Solid-phase extraction of plant thionins employing aluminum silicate based extraction columns.  

PubMed

Thionins belong to a family of cysteine-rich, low-molecular-weight (?5 KDa) biologically active proteins in the plant kingdom. They display a broad cellular toxicity against a wide range of organisms and eukaryotic cell lines. Thionins protect plants against different pathogens, including bacteria and fungi. A highly selective solid-phase extraction method for plant thionins is reported deploying aluminum silicate (3:2 mullite) powder as a sorbent in extraction columns. Mullite was shown to considerably improve selectivity compared to a previously described zirconium silicate embedded poly(styrene-co-divinylbenzene) monolithic polymer. Due to the presence of aluminum(III), mullite offers electrostatic interactions for the selective isolation of cysteine-rich proteins. In comparison to zirconium(IV) silicate, aluminum(III) silicate showed reduced interactions towards proteins which resulted into superior washings of unspecific compounds while still retaining cysteine-rich thionins. In the presented study, European mistletoe, wheat and barley samples were subjected to solid-phase extraction analysis for isolation of viscotoxins, purothionins and hordothionins, respectively. Matrix-assisted laser desorption/ionization time of flight mass spectroscopy was used for determining the selectivity of the sorbent toward thionins. The selectively retained thionins were quantified by colorimetric detection using the bicinchoninic acid assay. For peptide mass-fingerprint analysis tryptic digests of eluates were examined. PMID:24913248

Hussain, Shah; Güzel, Yüksel; Pezzei, Cornelia; Rainer, Matthias; Huck, Christian W; Bonn, Günther K

2014-08-01

23

Hydrodynamics of a packed countercurrent column for the gas extraction  

SciTech Connect

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 {alpha}-Tocopherol + carbon dioxide. A distinctive change in the flooding mechanisms from liquid layer flooding to bubble column flooding was observed. The different liquids, water and Toco, showed the same flooding behavior, indicating that the influence of the density on the flooding behavior prevails over the influence of any other physical property of the liquid. The foamability of the surfactant solution decreased significantly with increasing pressure--its influence on the flooding behavior could not be proved. The liquid holdup ranged between 2% and 6%. The dry pressure drop adhered to the Ergun equation.

Stockfleth, R.; Brunner, G.

1999-10-01

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

Effects of pulsed and oscillatory flow on water vapor removal from a laboratory soil column. Final report, November 1993  

SciTech Connect

Subsurface contamination by volatile organic contaminants (VOC`s) in the vadose zone and groundwater is primarily due to leaking underground storage tanks and industrial spills. Soil vapor extraction is a technique that is being used successfully to remove VOC`s from the subsurface. A flow of air is established through the soil to remove the vapor phase component of the contaminant. Soil vapor extraction will initially remove high levels of contaminant that is already present in the macropores. The concentration will start to decline as the removal from the soil matrix becomes limited by diffusion of contaminant from regions away from the air flow paths. This study examines potential methods of overcoming the diffusion limitation by adding an oscillatory component to the steady air flow and by pulsed flow, which involves turning air flow on and off at predetermined intervals. The study considered only the removal of water from the soil to try to establish general vapor behavior in the soil under the imposed conditions. Based on a statistical analysis, both the oscillatory and pulsed flow showed an improved water removal rate over the steady state flow. The effect of oscillatory flow was only examined at higher frequencies. The literature indicates that oscillations at lower frequencies may be more effective. Pulsed flow showed the most efficient removal of water compared to steady state conditions. The pulsed flow was most efficient because rather than reducing the diffusion limitation, the system would shut down and wait for diffusion to occur. This optimizes energy consumption, but does not reduce treatment time. The oscillatory flow actually reduced the diffusion limitation within the column which could result in a shorter treatment time.

Morrow, K.E.

1993-05-01

26

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

27

Grid-controlled extraction of pulsed ion beams  

NASA Astrophysics Data System (ADS)

Experimental results are presented on a method for extracting well-focused ion beams from plasma sources with time-varying properties. An electrostatic grid was used to stop the flow of plasma electrons so that only ions entered the extraction gap. In this case, ion flow in the gap was controlled by space-charge effects as it would be with a thermionic ion source. Constant extracted current was observed even with large variations of source flux. An insulator spark source and a metal-vapor vacuum arc were used to generate pulsed ion beams. With a hydrocarbon spark, current densities of 44 mA/cm2 were achieved at 20-kV extractor voltage for an 8-?s pulse. With an aluminum-vapor arc, a current density of 15 mA/cm2 (0.3 A total) was measured for a 50-?s pulse.

Humphries, S., Jr.; Burkhart, C.; Coffey, S.; Cooper, G.; Len, L. K.; Savage, M.; Woodall, D. M.; Rutkowski, H.; Oona, H.; Shurter, R.

1986-03-01

28

Grid-controlled extraction of pulsed ion beams  

SciTech Connect

Experimental results are presented on a method for extracting well-focused ion beams from plasma sources with time-varying properties. An electrostatic grid was used to stop the flow of plasma electrons so that only ions entered the extraction gap. In this case, ion flow in the gap was controlled by space-charge effects as it would be with a thermionic ion source. Constant extracted current was observed even with large variations of source flux. An insulator spark source and a metal-vapor vacuum arc were used to generate pulsed ion beams. With a hydrocarbon spark, current densities of 44 mA/cm/sup 2/ were achieved at 20-kV extractor voltage for an 8-..mu..s pulse. With an aluminum-vapor arc, a current density of 15 mA/cm/sup 2/ (0.3 A total) was measured for a 50-..mu..s pulse.

Humphries, S. Jr.; Burkhart, C.; Coffey, S.; Cooper, G.; Len, L.K.; Savage, M.; Woodall, D.M.; Rutkowski, H.; Oona, H.; Shurter, R.

1986-03-15

29

[Preparation and applications of a supported liquid-liquid extraction column with a composite diatomite material].  

PubMed

A rapid and special supported liquid-liquid extraction (SLE) column was developed with a composite diatomite material. The SLE column was evaluated by high performance liquid chromatography (HPLC) with acidic, neutral and alkaline compounds dissolved in water. Furthermore, some real complex samples were also analyzed by HPLC with the SLE method. The recoveries of benzoic acid (acidic), p-nitroaniline (alkaline) and 4-hydroxy-benzoic methyl ester (neutral) treated by the SLE column were 90.6%, 98.1% and 97.7%. However, the recoveries of the three compounds treated by traditional liquid-liquid extraction (LLE) method were 71.9%, 81.9% and 83.9%. The results showed that the SLE technique had higher recoveries than the traditional LLE method. The spiked recoveries of the complex samples, such as benzoic acid in Sprite and dexamethasone acetate, chlorphenamine maleate, indomethacin in bovine serum, were between 80% and 110% and the relative standard deviations (RSDs) were less than 15%. For biological specimen, the results could be accepted. Meantime, many disadvantages associated with traditional LLE method, such as emulsion formation, didn't occur using SLE column. The SLE column technique is a good sample preparation method with many advantages, such as rapid, simple, robust, easily automated, high recovery and high-throughput, which would be widely used in the future. PMID:23256382

Bao, Jianmin; Ma, Zhishuang; Sun, Ying; Wang, Yongzun; Li, Youxin

2012-08-01

30

Pulsed power supply for PAR injection/extraction septum magnet  

SciTech Connect

A 22.5 {mu}H, 22.5 m{Omega} transformer septum magnet must be pulsed at a 60 Hz rate to inject beam from a 450 MeV positron linac into a positron accumulator ring (PAR) and to extract beam from it. Of the 60 pulses per second the first 24 are used for injection and the 30th for extraction. The 25th through the 29th are not used. This pattern is repeated continuously. A design study was performed of the power supply proposed in the APS Title I design. This supply produces a pulse that is approximately a half-sine-wave with a base width of approximately 1/3 ms; its peak current is adjustable from 3.5kA to 4.7kA and is repeatable within {+-}0.05%. The septum steel is reset by a half-sine pulse of reverse polarity a few milliseconds after the forward current pulse. No beam is present during reset. The use of the transformer design minimizes the cost of the capacitors used for energy storage.

McGhee, D.G.

1990-09-23

31

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

32

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

33

The extraction of thorium by calix[6]arene columns for urine analysis.  

PubMed

Thorium is a natural alpha-emitting element occurring in various ores and has numerous industrial applications. Routine monitoring of potentially exposed workers is generally achieved through radiobioassay (urine and faeces). The procedures currently used for analysing actinides such as thorium in urine require lengthy chemical separation associated with long counting times by alpha-spectrometry due to low activity levels. Thus, their main drawback is that they are time-consuming, which limits the frequency and flexibility of individual monitoring. In this context, this study developed new radiochemical procedures based on the use of tertbutylcalix[6]arenes bearing three carboxylic acid groups or three hydroxamic acid groups. These previous works demonstrated that these macrocyclic molecules immobilised on an inert solid support are excellent extractants for uranium, plutonium and americium. In this study, the authors investigated the thorium extraction by calix[6]arene columns. Experiments were performed on synthetic solutions and on real urine samples. The influence of various parameters, such as the thorium solution pH and the column flow rate on thorium extraction, was studied. The results showed that both calix[6]arenes are efficient to extract thorium. Thorium extraction is quantitative from pH = 2 for synthetic solution and from pH = 3 for real urine samples. This study has demonstrated that the column flow rate is a crucial parameter since its value must not be too high to achieve the steady-state complexation equilibrium. Finally, these results will be compared with those obtained for other actinides (U, Pu and Am) and the conditions of actinides' separation will be discussed. PMID:21159742

Mekki, S; Bouvier-Capely, C; Jalouali, R; Rebière, F

2011-03-01

34

Monolithic silica capillary column extraction of methamphetamine and amphetamine in urine coupled with thin-layer chromatographic detection  

Microsoft Academic Search

A monolithic silica capillary column was first developed in Japan in 2001 as a new tool for better liquid chromatographic\\u000a separation. The column is made of C18-bonded monolithic silica packed into a capillary glass tube (0.20 mm i.d.). In this study, we used this column for solid-phase\\u000a extraction of methamphetamine (MA) and amphetamine (AP) in urine. Chromatographic separation was achieved

Akihiro Nakamoto; Akira Namera; Manami Nishida; Mikio Yashiki; Takako Kuramoto; Yoshiyuki Takei; Masahiro Furuno; Hiroyoshi Minakuchi; Kazuki Nakanishi; Kojiro Kimura

2006-01-01

35

Comparison of customized spin-column and salt-precipitation finger-prick blood DNA extraction.  

PubMed

gDNA (genomic DNA extraction from blood is a fundamental process in many diagnostic, identification and research applications. Numerous extraction methods have been reported and are available commercially. However, there is insufficient understanding of the impact of chemical buffers on DNA yield from either whole or nucleated blood. Moreover, these commercial kits are often costly, constraining less well-funded laboratories to traditional and more cost-effective salt-precipitation methods. Towards this, we compared a salt-precipitation and a customized cost-effective spin-column-based method, studying the impact of different chemical constituents on the yields. This customized method resulted in a shortening of the extraction process, higher gDNA yields, and more successful PCR amplification of gDNA genes compared with the salt-precipitation method. Optimizing different chemical buffers on whole- and nucleated blood materials further revealed that certain chemicals boosted extractions from whole- but not nucleated blood. These findings may be useful to laboratories that do not have ready access to commercial kits, and improve their nucleic acid extractions from blood economically. PMID:25222694

Poh, Jun-Jie; Gan, Samuel Ken-En

2014-01-01

36

Comparison of customized spin-column and salt-precipitation finger-prick blood DNA extraction  

PubMed Central

gDNA (genomic DNA extraction from blood is a fundamental process in many diagnostic, identification and research applications. Numerous extraction methods have been reported and are available commercially. However, there is insufficient understanding of the impact of chemical buffers on DNA yield from either whole or nucleated blood. Moreover, these commercial kits are often costly, constraining less well-funded laboratories to traditional and more cost-effective salt-precipitation methods. Towards this, we compared a salt-precipitation and a customized cost-effective spin-column-based method, studying the impact of different chemical constituents on the yields. This customized method resulted in a shortening of the extraction process, higher gDNA yields, and more successful PCR amplification of gDNA genes compared with the salt-precipitation method. Optimizing different chemical buffers on whole- and nucleated blood materials further revealed that certain chemicals boosted extractions from whole- but not nucleated blood. These findings may be useful to laboratories that do not have ready access to commercial kits, and improve their nucleic acid extractions from blood economically. PMID:25222694

Poh, Jun-Jie; Gan, Samuel Ken-En

2014-01-01

37

Micro-column solid phase extraction to determine uranium and thorium in environmental samples.  

PubMed

Extraction chromatographic separation techniques based on U/TEVA and TEVA resins were utilized to separate uranium and thorium isotopes in complex matrices from environmental samples. This approach has the advantages of ease of quantitative analysis, small sample size, an absence of mixed waste solvents, complete separation of U/Th isotopes, acceptable chemical yields and good energy resolution in the alpha spectrum. The procedure for analyzing alpha-emitting isotopes of uranium and thorium in geothermal water from Peito, Taiwan, is illustrated in detail. It involves sample pre-concentration, filtration and separation by highly selective extraction chromatographic resins, followed by electroplating and alpha-spectroscopy. The analytical results show a chemical recovery exceeding 55% for U and 65% for Th, respectively, under optimized conditions. The efficient and cost-effective use of recyclable columns makes the analytical methods simple, accurate, rapid, reliable and robust. PMID:18430577

Tsai, Tsuey-Lin; Lin, Chun-Chih; Chu, Tieh-Chi

2008-08-01

38

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

39

Pulsed extraction of ionization from helium buffer gas  

E-print Network

The migration of intense ionization created in helium buffer gas under the influence of applied electric fields is considered. First the chemical evolution of the ionization created by fast heavy-ion beams is described. Straight forward estimates of the lifetimes for charge exchange indicate a clear suppression of charge exchange during ion migration in low pressure helium. Then self-consistent calculations of the migration of the ions in the electric field of a gas-filled cell at the National Superconducting Cyclotron Laboratory (NSCL) using a Particle-In-Cell computer code are presented. The results of the calculations are compared to measurements of the extracted ion current caused by beam pulses injected into the NSCL gas cell.

D. J. Morrissey; G. Bollen; M. Facina; S. Schwarz

2008-08-13

40

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

41

Parallel extraction columns and parallel analytical columns coupled with liquid chromatography/tandem mass spectrometry for on-line simultaneous quantification of a drug candidate and its six metabolites in dog plasma.  

PubMed

A method with parallel extraction columns and parallel analytical columns (PEC-PAC) for on-line high-flow liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and validated for simultaneous quantification of a drug candidate and its six metabolites in dog plasma. Two on-line extraction columns were used in parallel for sample extraction and two analytical columns were used in parallel for separation and analysis. The plasma samples, after addition of an internal standard solution, were directly injected onto the PEC-PAC system for purification and analysis. This method allowed the use of one of the extraction columns for analyte purification while the other was being equilibrated. Similarly, one of the analytical columns was employed to separate the analytes while the other was undergoing equilibration. Therefore, the time needed for re-conditioning both extraction and analytical columns was not added to the total analysis time, which resulted in a shorter run time and higher throughput. Moreover, the on-line column extraction LC/MS/MS method made it possible to extract and analyze all seven analytes simultaneously with good precision and accuracy despite their chemical class diversity that included primary, secondary and tertiary amines, an alcohol, an aldehyde and a carboxylic acid. The method was validated with the standard curve ranging from 5.00 to 5000 ng/mL. The intra- and inter-day precision was no more than 8% CV and the assay accuracy was between 95 and 107%. PMID:11746878

Xia, Y Q; Hop, C E; Liu, D Q; Vincent, S H; Chiu, S H

2001-01-01

42

Separation and determination of 4-methylimidazole, 2-methylimidazole and 5-hydroxymethylfurfural in beverages by amino trap column coupled with pulsed amperometric detection.  

PubMed

A method for simultaneous determination of 4-methylimidazole (4-MeI), 2-methylimidazole (2-MeI) and 5-hydroxymethylfurfural (HMF) in beverages was developed using solid-phase extraction (SPE) and amino trap column coupled with pulsed amperometric detection (AMTC-PAD). A single amino trap column (P/N: 046122) was first applied to separate the targeted analytes in samples after SPE pretreatment. This method demonstrated low limit of quantification (0.030mg/L for methylimidazoles and 0.300mg/L for HMF) and excellent linearity with correlation of determination (R(2)=0.999 for 2-MeI, 0.997 for 4-MeI and 0.998 for HMF). Nearly no 2-MeI was found in all soft drinks. However, 4-MeI could be detected in cola drinks and soft drinks containing caramel colour (ranging from 0.13 to 0.34mg/L), whereas HMF were only found in cola drinks (ranging from 1.07 to 4.47mg/L). Thus, AMTC-PAD technique would be a valid and inexpensive alternative to analysis of 4-MeI, 2-MeI and HMF. PMID:25236220

Xu, Xian-Bing; Liu, Ding-Bo; Yu, Shu-Juan; Yu, Pei; Zhao, Zhen-Gang

2015-02-15

43

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

44

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

45

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

46

Automatic vertebral column extraction by whole-body bone SPECT scan.  

PubMed

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. PMID:23690878

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

2013-01-01

47

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. PMID:23690878

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

2013-01-01

49

Extraction of cesium from an alkaline leaching solution of spent catalysts using an ion-exchange column  

SciTech Connect

The selective extraction of cesium from an alkaline leaching solution of spent catalysts using phenolic resins was studied. The resins were synthesized by alkaline polycondensation of formaldehyde by phenol, resorcinol, catechol, and phloroglucinol. Their ionoselectivities for five alkali metals were evaluated with a solid-liquid extraction, and their ion-exchange capacities were compared. The resin with the best selectivity for cesium was tested with a real solution at different pH values. An on-column extraction is proposed to obtain cesium with high purity.

Dumont, N.; Favre-Reguillon, A.; Dunjic, B.; Lemaire, M. [Institut De Recherches sur la Catalyse et Laboratoire de Catalyse et Synthese Organique, Villeubanne (France)

1996-04-01

50

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

51

Separation of 99m Tc from parent 99 Mo by solid-phase column extraction as a simple option for a new 99m Tc generator concept  

Microsoft Academic Search

Evidence is obtained to show that the liquidliquid extraction separation of99mTc from99Mo with methyl ethyl ketone, methyl propyl ketone and methyl isobutyl ketone can be transformed into a solid-phase column extraction procedure. The aqueous alkaline99molybdate solution is immobilized on a column of a granular large-pore diatomaceous earch support, which is the neluted with the abovementioned extractants. Rapid and clean separation

T. Braun; H. Imura; N. Suzuki

1987-01-01

52

A post-column extraction system for the determination of tertiary amines by liquid chromatography with chemiluminescence detection  

Microsoft Academic Search

Summary  The combination of an ion-pair extraction detection system with peroxyoxalate chemiluminescence detection has been investigated.\\u000a Ion-pairs of protonated tertiary amines with a chemiluminescent counter ion are on-line post-column extracted to 1,2-dichloroethane\\u000a containing bis(2,4,6-trichlorophenyl)oxalate (TCPO). Hydrogen peroxide is added to the organic phase by means of a solid-state\\u000a perhydrit reactor. The influence of the base catalyst (imidazole) on the chemiluminescence reaction

P. J. M. Kwakman; U. A. Th. Brinkman; R. W. Frei; G. J. de Jong; F. J. Spruit; N. G. F. M. Lammers; J. H. M. van den Berg

1987-01-01

53

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

NASA Astrophysics Data System (ADS)

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

2010-05-01

54

Binary solvent extraction system and extraction time effects on phenolic antioxidants from kenaf seeds (Hibiscus cannabinus L.) extracted by a pulsed ultrasonic-assisted extraction.  

PubMed

The aim of this study was to determine the best parameter for extracting phenolic-enriched kenaf (Hibiscus cannabinus L.) seeds by a pulsed ultrasonic-assisted extraction. The antioxidant activities of ultrasonic-assisted kenaf seed extracts (KSE) were determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, ? -carotene bleaching inhibition assay, and ferric reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total flavonoid content (TFC) evaluations were carried out to determine the phenolic and flavonoid contents in KSE. The KSE from the best extraction parameter was then subjected to high performance liquid chromatography (HPLC) to quantify the phenolic compounds. The optimised extraction condition employed 80% ethanol for 15?min, with the highest values determined for the DPPH, ABTS, and FRAP assay. KSE contained mainly tannic acid (2302.20?mg/100?g extract) and sinapic acid (1198.22?mg/100?g extract), which can be used as alternative antioxidants in the food industry. PMID:24592184

Wong, Yu Hua; Lau, Hwee Wen; Tan, Chin Ping; Long, Kamariah; Nyam, Kar Lin

2014-01-01

55

Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption and Range During the ASCENDS 2009-2011 Airborne Campaigns  

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 mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar only on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear C02 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed in detail and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs altitude. The measurements showed -1 ppm random errors for 8-10 km altitudes and -30 sec averaging times. For the 2010 ASCENDS campaigns we flew the CO2 lidar on the NASA DC-8 and added an O2 lidar channel. During July 2010 we made measurements of CO2 and O2 column absorption during longer flights over Railroad Valley NV, the Pacific Ocean and over Lamont OK. CO2 measurements were made with 30 steps/scan, 300 scans/sec and improved line resolution and receiver sensitivity. Analysis of the 2010 CO2 measurements shows the expected -linear change of DOD with altitude. For measurements at altitudes> 6 km the random errors were 0.3 ppm for 80 sec averaging times. For the summer 2011 ASCENDS campaigns we made further improvements to the lidar's CO2 line scan and receiver sensitivity. The seven flights in the 2011 Ascends campaign were flown over a wide variety of surface and cloud conditions in the US, which produced a wide variety of lidar signal conditions. Details of the lidar measurements and their analysis will be described in the presentation.

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

2012-01-01

56

Analysis of Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption During the ASCENDS 2009-2011 Airborne Campaigns  

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 mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear CO2 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs altitude. The measurements showed 1 ppm random errors for 8-10 km altitudes and 30 sec averaging times. For the 2010 ASCENDS campaigns we flew the CO2lidar on the NASA DC-8 and added an 02lidar channel. During July 2010 we made measurements of CO2 and O2 column absorption during longer flights over Railroad Valley NV, the Pacific Ocean and over Lamont OK. CO2 measurements were made with 30 steps/scan, 300 scans/sec and improved line resolution and receiver sensitivity. Analysis of the 2010 CO2 measurements shows the expected linear change of DOD with altitude. For measurements at altitudes> 6 km the random errors were 0.3 ppm for 80 sec averaging times. For the summer 2011 ASCENDS campaigns we made further improvements to the lidar's CO2 line scan and receiver sensitivity. We demonstrated measurements over the California Central Valley, to stratus cloud tops over the Pacific Ocean, over mountain regions with snow, and over several areas with broken clouds. Details of the lidar measurements and their analysis will be described in the presentation.

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

2012-01-01

57

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

NASA Astrophysics Data System (ADS)

We have developed a lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA’s planned ASCENDS 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 stepped in wavelength across the CO2 line and an O2 line region during the measurement. The 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. 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 a selected CO2 line with 20 steps per scan. The line scan rate is 450 Hz, laser pulse energy is 25 uJ and laser pulse widths are 1 usec. 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 October and December 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin and broken clouds. Atmospheric CO2 column measurements using the 1571.4, 1572.02 and 1572.33 nm CO2 lines. Two flights were made above the 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. This spring we improved the aircraft’s nadir window. During July and August 2009 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 Virginia. Strong laser signals and clear 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. 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. Ed Browell and Gary Spiers led the LaRC and JPL teams. More details of the flights, measurements and their analysis will be described in the presentation.

Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C. J.; Hasselbrack, W. E.; Sun, X.

2009-12-01

58

Improving the extraction of tetrachloroethylene from soil columns using surfactant gradient systems  

NASA Astrophysics Data System (ADS)

In this work, we extend the recently developed gradient approach for surfactant-enhanced remediation of dense non-aqueous phase liquid (DNAPL)-impacted sites. The goal of the gradient approach is to maximize the DNAPL solubilization capacity in swollen micelles (Type I aqueous microemulsions) while at the same time minimizing the potential for DNAPL mobilization. In this work, we introduce a modified version of the capillary/trapping curve that we refer to as the gradient curve to help interpret and/or design the gradient approach. The gradient curve presents the residual DNAPL saturation as a function of interfacial tension and microemulsion viscosity. This approach demonstrates that keeping a low viscosity of the microemulsion phase is not only important for keeping a low head loss during surfactant flooding but also to prevent oil mobilization. Eight microemulsion systems were evaluated in this research; these systems were evaluated based on their tetrachloroethylene (PCE) solubilization capacity, interfacial tension (IFT), viscosity, density, and coalescence kinetics. Two of these systems were chosen for evaluation in site-specific column tests using an increasing electrolyte gradient to produce a decreasing IFT/increasing solubilization gradient system. The column studies were conducted with media from Dover Air Force Base in Dover, DE. Both solubilized and mobilized DNAPL were quantified. During the column studies, we observed that substantial PCE was mobilized when the residual level of PCE in the column was significantly higher than the steady-state residual saturation level being approach (as predicted from the gradient curve). Four column studies were performed, three of which were used to asses the validity of the gradient curve in predicting the residual saturation after each gradient step. From these tests we observed that starting IFTs of less than 1 mN/m all produced the same mobilization potential. In the last column, we used an additional gradient step with an initial IFT above 1 mN/m to dramatically reduce the amount of PCE mobilize. Based on the good agreement between column results and projections based on the gradient curve, we propose this as a preferred method for designing gradient surfactant flushing systems.

Childs, Jeffrey D.; Acosta, Edgar; Knox, Robert; Harwell, Jeffrey H.; Sabatini, David A.

2004-07-01

59

Grid-controlled extraction of pulsed ion beams  

Microsoft Academic Search

Experimental results are presented on a method for extracting well-focused ion beams from plasma sources with time-varying properties. An electrostatic grid was used to stop the flow of plasma electrons so that only ions entered the extraction gap. In this case, ion flow in the gap was controlled by space-charge effects as it would be with a thermionic ion source.

S. Humphries Jr.; C. Burkhart; S. Coffey; G. Cooper; L. K. Len; M. Savage; D. M. Woodall; H. Rutkowski; H. Oona; R. Shurter

1986-01-01

60

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

NASA Astrophysics Data System (ADS)

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, the noise reduction circuit, the comparator and the small DAC that combined both the reference voltage ratios and capacitance ratios. In the ALU, the object categorization pre-processing is performed by the each macro block of 3 × 3 pixels which has a reference pixel and its neighboring eight pixels. The three image features which are the edge of object, the direction of edge-vector and the average of light-intensity of 3 × 3 pixels corresponded to each pixel are extracted by the ALUs. The image and the results of the object extraction pre-processing are outputted by every 60-fps. The image sensor was fabricated by 0.35-?m 2P3M technology. The pixel pitch is 5.3-?m, the number of pixels is 640H × 360V and the chip size is 4.9-mm square.

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

2007-02-01

61

Use of cyanopropyl-bonded hplc column for bioassay-directed fractionation of organic extracts from incinerator emissions  

SciTech Connect

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 emitted by two different municipal waste incinerators and by a pilot-scale rotary kiln incinerator that was combusting polyethylene were fractionated by HPLC, and the mutagenicity of the fractions was determined by means of a microsuspension mutagenicity assay with Salmonella TA98. The CN-bonded silica columns provided high (80-100 percent) mass and mutagenicity recoveries for most emission extracts, and it fractionated the mutagenic activity. The results suggest that the emissions from municipal waste incinerators contain a high amount of direct-acting (-S9) mutagenic activity that is resolvable by HPLC using CN-bonded silica. Sub-fractionation of selected mutagenic HPLC fractions and subsequent analysis by gas chromatography/mass spectroscopy can be used to identify mutagenic species within complex incinerator emissions. The coupling of microsuspension bioassays to HPLC fractionation should be a useful tool for this type of analysis.

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

1992-01-01

62

Analysis of Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption in the ASCENDS 2011 and 2013 Airborne Campaigns  

NASA Astrophysics Data System (ADS)

We have developed a pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. The CO2 lidar flies on NASA's DC-8 aircraft and 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 with 300 scans per second. Our post-flight analysis estimates the lidar range and pulse energies at each wavelength every second. We then solve for the optimum CO2 absorption line shape, and calculated the Differential Optical Depth (DOD) at the line peak and the column average CO2 concentrations. We compared these to radiative transfer calculations based on the HITRAN 2008 database, the atmospheric conditions, and the CO2 concentrations sampled by in-situ sensors on the aircraft. Our team participated in the ASCENDS science flights during 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, over thin and broken clouds above the US Southwest and Iowa, and over forests near the WLEF tower in Wisconsin. Most flights had 5-6 altitude steps to > 12 km, and clear CO2 absorption line shapes were recorded. 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 10 second averaging, the scatter in the retrievals was typically 2-3 ppm and was limited by signal shot noise (i.e. the signal photon count). For flight altitudes above 5 km the biases in retrieved concentrations were 1-2 ppm. Analysis shows the decrease in CO2 due to vegetation when flying over Iowa cropland as well as the sudden increases in CO2 concentration near a coal-fired power plant in New Mexico. Our team also participated in the February 2013 ASCENDS flight campaign, flying over a variety of surfaces in the US, including over Railroad Valley NV, the California Central Valley, desert areas in Arizona, and over cold snow fields in the Rocky Mountains of Colorado and warmer snow in Iowa and Wisconsin. Our post-flight analyses showed that the retrievals of lidar range, lineshape and CO2 column absorption and concentrations worked well when measuring over topography with rapidly changing height and reflectivity, and through thin clouds. As expected, the relative reflectivity of snow surfaces near 1572 nm was small, about 10% of that of the desert, and good line fits and retrievals were made to these as well. Examples from analyzing the 2011 and 2013 measurements will be presented.

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

2013-12-01

63

Development of an immunoaffinity chromatography column for selective extraction of a new agonist phenylethylamine A from feed, meat and liver samples.  

PubMed

Phenylethanolamine A (PA) is a new emerged ?-adrenergic agonist that has been illegally used as an animal feed additive for growth promotion in China. In this study, an immunoaffinity chromatography (IAC) column for selective extraction of PA from swine feed, meat and liver samples was developed. The IAC column was constructed by covalently coupling specific polyclonal antibody (Ab) against PA to CNBr-activated Sepharose 4B and packed into a common solid phase extraction (SPE) cartridge. The extraction conditions including loading, washing and eluting solutions were carefully optimized. Under optimal conditions, the IAC column was characterized in terms of maximum capacity, selectivity, extraction recovery and stability. The maximum capacity of the ICA for PA extraction was found to be 239.4ng. For selectivity testing, 100ng of other three ?-adrenergic agonists (clenbuterol, ractopamine and salbutamol) was separately loaded onto the column, and it was observed that the tested compounds could not be captured on the column, e.g. the column could only selectively recognize PA. The recovery of the IAC for PA extraction was found within 96.47-101.98% when 10, 50 and 100ng PA were separately loaded onto IAC column. The IAC column was also applied to real sample extraction. Swine feed, meat and liver samples were collected and spiked with PA in range of 1.0-20ngg(-1). The spiked and unspiked samples were extracted by IAC column and measured by high performance liquid chromatography (HPLC). It was found that there was no detectable PA in the blank samples, and the extraction recoveries of the IAC for PA from the spiked samples were within 89.48-104.89%. The stability of the column was also tested. It was showed that after 35 times repeated usage, 60% of the maximum capacity was still remained. The proposed IAC was proven to be a feasible extraction method for PA from different matrices with the properties of high maximum capacity, selectivity, extraction efficiency and stability. PMID:24342511

Mei, Liyun; Cao, Biyun; Yang, Hong; Xie, Yun; Xu, Shouming; Deng, Anping

2014-01-15

64

Tricyclic antidepressants in serum by a Clin-ElutTM column extraction and high pressure liquid chromatographic analysis.  

PubMed

We sought a method for routine therapeutic monitoring of serum tricyclic antidepressants (TCAs) which offered good reproducibility, detection limits, linearity, and specificity, and which was simple, rapid, and inexpensive to perform. The method described utilizes Clin-Elut columns (Analytichem International, Inc., Lawndale, CA 90206) to facilitate the extraction. The analysis is by high pressure liquid chromatography (HPLC) with a CN bonded phase column, a mobile phase of acetonitrile/pH 7.0 phosphate/methanol and detection at 210 nm. This chromatographic system gives short equilibration times, stable calibration curves, high sensitivity and resolution, short retention times, and long column life. The method is useful for determination of amitriptyline, doxepin, imipramine, nortriptyline, nordoxepin, desipramine, and protriptyline. Trimipramine is used as an internal standard for the tertiary amines and protriptyline for the secondary amines. Recovery is linear from 25 ato 1,000 ng/ml. Rubber stoppers of a new formulation in Vacutainer blood collection tubes (Becton-Dickinson, Rutherford, NJ 07070) do not affect serum TCA levels. Sera from 53 psychiatric patients suffering from endogenous depression were analyzed using the procedure presented. The mean serum level of four patients on amitriptyline therapy having complete remission was 201 ng/ml (range, 123-259). The mean serum level of four patients on imipramine therapy rated as having complete remission was 200 ng/ml (range, 145-258). These values compare well with recently published therapeutic ranges. PMID:555578

Thoma, J J; Bondo, P B; Kozak, C M

1979-01-01

65

Theoretical study of a new energy extraction scheme of a chemically pumped pulsed iodine laser amplifier  

Microsoft Academic Search

A new energy extraction scheme of a chemically pumped pulsed large-scale iodine laser based on a high-pressure pulsed singlet oxygen generator is proposed. In previous investigations only low-pressure oxygen generators have been considered. Since they require a high iodine density for an efficient amplifier operation, the lifetime of the stored energy is correspondingly small and thus only small-sized iodine amplifiers

M. Endo; K. Kodama; Y. Handa; T. Uchiyama

1993-01-01

66

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

67

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 6.92 g/L was achieved under the following conditions: material-liquid ratio of 1:15 g/mL, electric field intensity of 16.88 kV/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

68

Effect of Pulsed Electric Field Treatments on Permeabilization and Extraction of Pigments from Chlorella vulgaris.  

PubMed

The effect of pulsed electric field (PEF) treatments of different intensities on the electroporation of the cytoplasmatic membrane of Chlorella vulgaris, and on the extraction of carotenoids and chlorophylls were investigated. Staining the cells with propidium iodide before and after the PEF treatment revealed the existence of reversible and irreversible electroporation. Application of PEF treatments in the range of 20-25 kV cm(-1) caused most of the population of C. vulgaris to be irreversibly electroporated even at short treatment times (5 pulses of 3 µs). However, at lower electric field strengths (10 kV cm(-1)), cells that were reversibly electroporated were observed even after 50 pulses of 3 µs. The electroporation of C. vulgaris cells by PEF higher than 15 kV cm(-1) and duration is higher than 15 µs increased significantly the extraction yield of intracellular components of C. vulgaris. The application of a 20 kV cm(-1) for 75 ?s increased the extraction yield just after the PEF treatment of the carotenoids, and chlorophylls a and b 0.5, 0.7, and 0.8 times, respectively. However, further increments in electric field strength and treatment time did not cause significant increments in the extraction yield. The extraction of carotenoids from PEF-treated C. vulgaris cells after 1 h of the application of the treatment significantly increased the extraction yield in comparison to the yield obtained from the cells extracted just after the PEF treatment. After PEF treatment at 20 kV cm(-1) for 75 µs, extraction yield for carotenoids, and chlorophylls a and b increased 1.2, 1.6, and 2.1 times, respectively. A high correlation was observed between irreversible electroporation and percentage of yield increase when the extraction was conducted after 1 h of the application of PEF treatment (R: 0.93), but not when the extraction was conducted just after PEF treatment (R: 0.67). PMID:24880235

Luengo, Elisa; Condón-Abanto, Santiago; Alvarez, Ignacio; Raso, Javier

2014-12-01

69

Analysis of trace amounts of carbon dioxide, oxygen and carbon monoxide in nitrogen using dual capillary columns and a pulsed discharge helium ionisation detector  

Microsoft Academic Search

Gas mixtures of trace amounts of carbon dioxide (CO2), dioxygen (O2), and carbon monoxide (CO) in dinitrogen (N2) were separated and quantified using parallel dual capillary columns and pulsed discharge helium ionisation detection (PDHID). The detection limits (9×10?9molmol?1 for CO2, 7×10?9molmol?1 for O2 and 37×10?9molmol?1 for CO) were lower than those reported previously for similar methods. Uncertainties were calculated and

M. Janse van Rensburg; A. Botha; E. Rohwer

2007-01-01

70

[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

71

One-step column chromatographic extraction with gradient elution followed by automatic separation of volatiles, flavonoids and polysaccharides from Citrus grandis.  

PubMed

Citrus grandis Tomentosa is widely used in traditional Chinese medicine and health foods. Its functional components include volatiles, flavonoids and polysaccharides which cannot be effectively extracted through traditional methods. A column chromatographic extraction with gradient elution was developed for one-step extraction of all bioactive substances from C. grandis. Dried material was loaded into a column with petroleum ether: ethanol (8:2, PE) and sequentially eluted with 2-fold PE, 3-fold ethanol: water (6:4) and 8-fold water. The elutes was separated into an ether fraction containing volatiles and an ethanol-water fraction containing flavonoids and polysaccharides. The later was separated into flavonoids and polysaccharides by 80% ethanol precipitation of polysaccharides. Through this procedure, volatiles, flavonoids and polysaccharides in C. grandis were simultaneously extracted at 98% extraction rates and simply separated at higher than 95% recovery rates. The method provides a simple and high-efficient extraction and separation of wide range bioactive substances. PMID:24128512

Han, Han-Bing; Li, Hui; Hao, Rui-Lin; Chen, Ya-Fei; Ni, He; Li, Hai-Hang

2014-02-15

72

Removal of sodium-24 by chromatographic extraction with a kieselguhr column and crown ether solution  

SciTech Connect

Sodium-24 was readily removed from aqueous solutions by a chromatographic process based on an isotopic exchange reaction. The reaction was carried out with a granular Kieselguhr column and a chloroform solution of crown ether-sodium picrate. The process took about 1 h and can be utilized in neutron activation analysis of many elements, Cl, Br, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Ru, In, Sn, Ce and W. It cannot be used, however, for alkali and alkaline earth elements. The amount of /sup 24/Na in a treated sample was 10/sup -2/ of the original amount. The Compton background was reduced in the range of ..gamma..-ray energy after the removal of sodium-24. 3 figures, 3 tables.

Kimura, T. (Japan Chemical Analysis Center, Chiba); Ishimori, T.; Hamada, T.

1982-06-01

73

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

74

Determination of Alkylphenols in Water by SolidPhase Extraction with On-column Derivatization Coupled with Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

An analytical methods based on the solid-phase extraction (SPE) with in situ derivatization followed by gas chromatography-mass spectrometry has been developed for the determination of alkylphenols (APs) in water samples. Two important APs, 4-n-nonylphenol and 4-t-octylphenol, were selected as the target compounds for method development. The SPE extraction was conducted on a C18 extraction cartridges with on column silylation by

Yang Bai-Juan; Jiang Feng-Hua; Xu Xiao-Qin; Chen Jun-Hui; Frank S. C. Lee

2007-01-01

75

Novel extraction algorithm for amplitude and phase measurement of ultrashort optical pulses via spectral phase interferometry  

E-print Network

We present a novel extraction algorithm for spectral phase interferometry for direct field reconstruction (SPIDER) for the so-called X-SPIDER configuration. Our approach largely extends the measurable time windows of pulses without requiring any modification to the experimental X-SPIDER set-up.

Pasquazi, Alessia; Azana, Jose; Moss, David J; Morandotti, Roberto

2014-01-01

76

The fast extraction kicker for J-PARC with a novel pulse compression system  

NASA Astrophysics Data System (ADS)

A fast extraction kicker magnet for the main ring of J-PARC has been developed. A lumped constant type magnet is employed for its structural simplicity and stability in high-voltage operation. A disadvantage of the lumped constant type, a slow rise time, was alleviated by the adoption of a newly developed magnetic pulse compression system. The effectiveness of the magnetic pulse compression system in sharpening the excitation current was confirmed both by a circuit simulation and experimentally. The newly developed fast extraction kicker system was operated successfully with a 30 kV charging voltage of the pulsed power supply. The required rise time of less than 1.1 ?s was achieved in the measurement.

Koseki, Kunio; Matsumoto, Hiroshi

2014-03-01

77

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 10 min irradiation time. For the microwave-assisted extraction, the optimal conditions were 82% ethanol, 10% power level and 7 min 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

78

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

79

High-Efficiency On-Line Solid-Phase Extraction Coupling to 15-150 um I.D. Column Liquid Chromatography for Proteomic Analysis  

SciTech Connect

Flexible manipulation of various properties of proteomic samples is important for proteomic analyses, but it has been little explored for newly developed approaches based on liquid chromatography (LC) in combination with mass spectrometry (MS). With miniaturization of the LC column inner diameter dimensions (required for improving the analysis sensitivity), this issue becomes more challenging due to the small flow rates and the increasing effects of extra column volume on the separation quality and its use for resolving complex proteomic mixtures. In this study, we used commercial switching valves (150-mm channels) to implement the on-line coupling of capillary LC columns with relatively large solid phase extraction (SPE) columns operated at 10,000 psi. With optimized column connections, switching modes, and SPE column dimensions, high-efficiency on-line SPE-capillary and nanoscale LC separations were obtained with peak capacities of~1000 for capillaries having inner diameters between 15 to 150 mm. The on-line coupled SPE columns increased the sample processing capabilities by~400-fold for sample solution volume and~10-fold for sample mass. The proteomic applications of this on-line SPE-capillary LC system were evaluated for analysis of both soluble and membrane protein tryptic digests. Used with an ion trap tandem MS we could typically identify 1100-1500 peptides for analyses in a single 5-hour run. Peptides extracted on the SPE column and eluted from the LC column covered a hydrophilicity/hydrophobicity range that include an estimated~98% of all the tryptic peptides. The present implementation also facilitates automation and enables use of both disposable SPE columns and electrospray emitters, providing a robust basis for routine proteomic analyses.

Shen, Yufeng (BATTELLE (PACIFIC NW LAB)); Moore, Ronald J. (BATTELLE (PACIFIC NW LAB)); Zhao, Rui (BATTELLE (PACIFIC NW LAB)); Blonder, Josip (BATTELLE (PACIFIC NW LAB)); Auberry, Deanna L. (BATTELLE (PACIFIC NW LAB)); Masselon, Christophe D. (BATTELLE (PACIFIC NW LAB)); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)); Hixson, Kim K. (BATTELLE (PACIFIC NW LAB)); Auberry, Kenneth J. (BATTELLE (PACIFIC NW LAB)); Smith, Richard D. (BATTELLE (PACIFIC NW LAB))

2003-07-15

80

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

81

Extraction of squalene from shark liver oil in a packed column using supercritical carbon dioxide  

SciTech Connect

Continuous extraction of squalene from shark liver oil using supercritical carbon dioxide was carried out in both laboratory and pilot scale plant. The shark liver oil contained around 50% by weight squalene, which was recovered as the main extract stream. The other major components in the oil were triglycerides, which were recovered as raffinate, and pristane, which was recovered as a second extract stream. Separation performance was determined as a function of temperature; pressure; oil to carbon dioxide flow rate ratio, packed height and type of packing; and reflux ratio. The pressure, temperature, and feed oil concentration of squalene determined the maximum loading of oil in carbon dioxide. The oil to carbon dioxide ratio determined the squalene concentration in both the product stream and raffinate stream. The ratio of oil flow rate to the flow rate of squalene required to just saturate carbon dioxide was found to be a useful correlating parameter for the oil loadings and product compositions. Of the three packings investigated, wire wool gave the best separation efficiency and Raschig rings the worst efficiency. Mass transfer correlations from the literature were used to estimate the number of transfer units (NTU) from experimental data and literature correlations. NTU`s from the experimental data were comparable to predictions at a pilot scale but were underpredicted at the laboratory scale. The use of reflux at the pilot scale enabled the concentration of squalene in the product stream to be increased from 92% by mass to a maximum of 99% by mass at fractionation conditions of 250 bar and 333 K.

Catchpole, O.J.; Kamp, J.C. von; Grey, J.B. [Industrial Research Limited, Lower Hutt (New Zealand)] [Industrial Research Limited, Lower Hutt (New Zealand)

1997-10-01

82

Modification of crosslinked glycidyl methacrylate-based polymers for boron-specific column extraction  

Microsoft Academic Search

Terpolymers of glycidyl methacrylate (0.4 mol) with methyl methacrylate (0.5 mol) and divinyl benzene (0.1 mol) in spherical beads form have been modified with N-methyl-d-glucamine in N-methyl pyrrolidone solvent. Polymers with (2.05 mmol g?1) functionality have moderate swelling ability (1.81 v\\/v0) and show excellent boron uptake ability (2.15 mmol g?1) for extraction of trace quantities of H3BO3 from aqueous solutions.

Niyazi Biçak; Nusret Bulutçu; Bahire Filiz ?enkal; Mustafa Gazi

2001-01-01

83

Molecularly imprinted spin column extraction coupled with high-performance liquid chromatography for the selective and simple determination of trace nitrophenols in water samples.  

PubMed

In this study, we developed a simple and selective spin column extraction technology utilizing hydrophilic molecularly imprinted polymers as the sorbents for extracting nitrophenol pollutants in water samples (the East Lake, the Yangtze River, and wastewater). The whole procedure was achieved by centrifugation of the spin column, and multiple samples were simultaneously processed with a low volume of solvent and without evaporation. Under the optimized condition, recoveries of nitrophenol compounds on the spin column packed with hydrophilic molecularly imprinted polymers ranged from 87.3 to 92.9% and an excellent purification effect was obtained. Compared with activated carbon, multi-walled carbon nanotubes, LC-C18 sorbents, hydrophilic molecularly imprinted polymers exhibited a highly selective recognition ability for nitrophenol compounds and satisfactory sample extraction efficiency. Subsequently, the spin column extraction coupled with high-performance liquid chromatography was established, which was found to be linear in the range of 2-1000 ng/mL for 2,4-dinitropehnol and 2-nitrophenol, and 6-1000 ng/mL for 4-nitrophenol with correlation coefficients greater than 0.998. The detection limits ranged from 0.3-0.5 ng/mL. It is shown that the proposed method can be used for the determination of trace nitrophenol pollutants in complex samples, which is not only beneficial for water quality analysis but also for environmental risk assessment. PMID:25175410

Jing, Tao; Zhou, Yusun; Wu, Wei; Liu, Min; Zhou, Yikai; Mei, Surong

2014-10-01

84

Pulsed electric field (PEF) as an intensification pretreatment for greener solvent lipid extraction from microalgae.  

PubMed

Microalgae, with their high lipid content, are a promising feedstock for renewable fuels. Traditionally, human and environmentally toxic solvents have been used to extract these lipids, diminishing the sustainability of this process. Herein, pulsed electric field technology was utilized as a process intensification strategy to enhance lipid extraction from Ankistrodesmus falcatus wet biomass using the green solvent, ethyl acetate. The extraction efficiency for ethyl acetate without PEF was lower (83-88%) than chloroform. In addition, the ethyl acetate exhibited a 2-h induction period, while the chloroform showed no time dependence. Utilizing PEF technology resulted in 90% of the cells being lysed and a significant enhancement in the rate of lipid recovery using ethyl acetate. The increase in lipid recovery was due to the presence of the electric field and not due to temperature effects. The PEF technology uses less energy than other PEF systems reported in the literature. PMID:23297018

Zbinden, Mauricio D Antezana; Sturm, Belinda S M; Nord, Ryan D; Carey, William J; Moore, David; Shinogle, Heather; Stagg-Williams, Susan M

2013-06-01

85

Compatibility of column inlet and adsorbent designs for processing of corn endosperm extract by expanded bed adsorption.  

PubMed

Corn has emerged as a viable host for expression of recombinant proteins; targeted expression to the endosperm has received particular attention. The protein extracts from corn endosperm differ from those of traditional hosts in regard to the nature of residual solids and extracted matrix contaminants. Each of these differences presents reasons for considering expanded bed adsorption for product capture and new considerations for limitations of the method. In this work three inlet-flow distribution devices (mesh, glass ballotini, and localized mixing) and six adsorbents with different physical (size and density), chemical (ligand), and base matrix properties were evaluated to determine conditions compatible with processing of crude corn endosperm extract by expanded bed adsorption. Of the inlet devices evaluated, the design with localized mixing at the inlet (as produced commercially by UpFront Chromatography A/S, Copenhagen, DK) allowed solids up to 550 microm into the column without clogging for all flow rates evaluated. A mesh at the inlet with size restriction of either 50 microm or 80 microm became clogged with very small corn particles (< 44 microm). When glass ballotini was used, large particles (550 microm) passed through for high flow rates (570 cm/h), but even small (< 44 microm) particles became trapped at a lower flow rate (180 cm/h). The physical and chemical properties of the resin determined whether solids could be eluted. The denser UpFront adsorbents allowed for complete elution of larger and more concentrated corn solids than the currently available Amersham Streamline adsorbents (Amersham Biosciences, Piscataway, NJ) as a result of the former's higher flow rate for the desired 2x expansion (570 cm/h for UpFront vs. 180 cm/h for Streamline). All corn solids < 162 microm eluted through nonderivatized UpFront resin. Larger corn solids began to accumulate due to their elevated sedimentation velocities. Feeds of < 44 microm solids at 0.45% and 2.0% dry weight successfully eluted through ion exchange adsorbents (DEAE and SP) from UpFront. However, significant accumulation occurred when the solids size increased to a feed of < 96 microm solids, thus indicating a weak interaction between corn solids and both forms of ion exchange ligands. Expanded beds operated with Streamline ion exchange adsorbents (DEAE and SP) did not allow full elution of corn solids of < 44 microm. A hyperdiffuse style EBA resin produced by Biosepra (Ciphergen Biosystems, Fremont, CA) with CM functionality showed a severe interaction with corn solids that collapsed the expanded bed and could not be eliminated with elevated flow rates or higher salt concentration. PMID:15281107

Menkhaus, Todd J; Glatz, Charles E

2004-08-01

86

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

87

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

88

Analysis of trace amounts of carbon dioxide, oxygen and carbon monoxide in nitrogen using dual capillary columns and a pulsed discharge helium ionisation detector.  

PubMed

Gas mixtures of trace amounts of carbon dioxide (CO(2)), dioxygen (O(2)), and carbon monoxide (CO) in dinitrogen (N(2)) were separated and quantified using parallel dual capillary columns and pulsed discharge helium ionisation detection (PDHID). The detection limits (9 x 10(-9) mol mol(-1) for CO(2), 7 x 10(-9) mol mol(-1) for O(2) and 37 x 10(-9) mol mol(-1) for CO) were lower than those reported previously for similar methods. Uncertainties were calculated and results were validated by comparison of the CO and CO(2) results with those obtained using conventional methods. The method was also used to analyse nitrogen, carbon dioxide and carbon monoxide in oxygen. PMID:17765907

Janse van Rensburg, M; Botha, A; Rohwer, E

2007-10-01

89

Expanding the potential of standard flow cytometry by extracting fluorescence lifetimes from cytometric pulse shifts.  

PubMed

Fluorescence lifetime measurements provide information about the fluorescence relaxation, or intensity decay, of organic fluorophores, fluorescent proteins, and other inorganic molecules that fluoresce. The fluorescence lifetime is emerging in flow cytometry and is helpful in a variety of multiparametric, single cell measurements because it is not impacted by nonlinearity that can occur with fluorescence intensity measurements. Yet time-resolved cytometry systems rely on major hardware modifications making the methodology difficult to reproduce. The motivation of this work is, by taking advantage of the dynamic nature of flow cytometry sample detection and applying digital signal processing methods, to measure fluorescence lifetimes using an unmodified flow cytometer. We collect a new lifetime-dependent parameter, referred to herein as the fluorescence-pulse-delay (FPD), and prove it is a valid representation of the average fluorescence lifetime. To verify we generated cytometric pulses in simulation, with light emitting diode (LED) pulsation, and with true fluorescence measurements of cells and microspheres. Each pulse is digitized and used in algorithms to extract an average fluorescence lifetime inherent in the signal. A range of fluorescence lifetimes is measurable with this approach including standard organic fluorophore lifetimes (?1 to 22 ns) as well as small, simulated shifts (0.1 ns) under standard conditions (reported herein). This contribution demonstrates how digital data acquisition and signal processing can reveal time-dependent information foreshadowing the exploitation of full waveform analysis for quantification of similar photo-physical events within single cells. © 2014 The Authors. Published by Wiley Periodicals, Inc. PMID:25274073

Cao, Ruofan; Naivar, Mark A; Wilder, Mark; Houston, Jessica P

2014-12-01

90

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

91

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

92

A study of solvent refining of cottonseed oil by use of a rotating core countercurrent extraction column  

E-print Network

$ TABIK I Caustic Refin1ng Loss Test of Solvent Refined Cottonseed 011 Saale Crude Cottonseed 011 Zsopropanol Extracted 011 Acetone Extracted 011 Methanol Extracted 011 Free Fatty Acid $ Ref1ning Method Amount of HaOH Solutions ~m ~gm~o... $ TABIK I Caustic Refin1ng Loss Test of Solvent Refined Cottonseed 011 Saale Crude Cottonseed 011 Zsopropanol Extracted 011 Acetone Extracted 011 Methanol Extracted 011 Free Fatty Acid $ Ref1ning Method Amount of HaOH Solutions ~m ~gm~o...

Holbrook, Charles Ray

2012-06-07

93

Determination of Commonly Used Herbicides in Surface Water Using SolidPhase Extraction and Dual-Column HPLC-DAD  

Microsoft Academic Search

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 (C18) Empore extraction disks, octadecyl (C18), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency.

GÜL ÖZHAN; SIBEL ÖZDEN; BUKET ALPERTUNGA

2005-01-01

94

On-line hyphenation of solid-phase extraction to chromatographic separation of sulfonamides with fused-core columns in sequential injection chromatography.  

PubMed

On-line sample pretreatment (clean-up and analyte preconcentration) is for the first time coupled to sequential injection chromatography. The approach combines anion-exchange solid-phase extraction and the highly effective pentafluorophenylpropyl (F5) fused-core particle column for separation of eight sulfonamide antibiotics with similar structures (sulfathiazole, sulfanilamide, sulfacetamide, sulfadiazine, sulfamerazine, sulfadimidine, sulfamethoxazole and sulfadimethoxine). The stationary phase was selected after a critical comparison of the performance achieved by three fused-core reversed phase columns (Ascentis(®) Express RP-Amide, Phenyl-Hexyl, and F5) and two monolithic columns (Chromolith(®) High Resolution RP-18 and CN). Acetonitrile and acetate buffer pH 5.0 at 0.60mLmin(-1) were used as mobile phase to perform the separations before spectrophotometric detection. The first mobile phase was successfully used as eluent from SPE column ensuring transfer of a narrow zone to the chromatographic column. Enrichment factors up to 39.2 were achieved with a 500µL sample volume. The developed procedure showed analysis time <10.5min, resolutions >1.83 with peak symmetry ?1.52, LODs between 4.9 and 27µgL(-1), linear response ranges from 30.0 to 1000.0µgL(-1) (r(2)>0.996) and RSDs of peak heights <2.9% (n=6) at a 100µgL(-1) level and enabled the screening control of freshwater samples contaminated at the 100µgL(-1) level. The proposed approach expanded the analytical potentiality of SIC and avoided the time-consuming batch sample pretreatment step, thus minimizing risks of sample contamination and analyte losses. PMID:25435240

Batista, Alex D; Chocholouš, Petr; Satínský, Dalibor; Solich, Petr; Rocha, Fábio R P

2015-02-01

95

Molecularly-imprinted solid phase extraction of catechol from aqueous effluents for its selective determination by differential pulse voltammetry  

Microsoft Academic Search

A polymeric sorbent based on molecular imprinting technology has been synthesized and applied to selectively extract catechol from water samples with subsequent determination by differential pulse voltammetry (DPV). The non-covalent polymer was prepared by bulk polymerization using catechol and 4-vinylpyridine as template and monomer, respectively. The effect of the flow and chemical variables associated to the performance of the solid

César Ricardo Teixeira Tarley; Lauro Tatsuo Kubota

2005-01-01

96

Extraction of negative ions from pulsed electronegative inductively coupled plasmas having a radio-frequency substrate bias  

E-print Network

Extraction of negative ions from pulsed electronegative inductively coupled plasmas having a radio ions into features. By modulating power in inductively coupled plasmas ICPs , the plasma potential coupled plasmas ICPs powered at radio frequency rf where the carrier frequency the power is square wave

Kushner, Mark

97

Solid phase extraction and spectrophotometric determination of mercury by adsorption of its diphenylthiocarbazone complex on an alumina column.  

PubMed

A simple method has been developed for the preconcentration of mercury based on the adsorption of its diphenylthiocarbazone complex on a neutral alumina column. The influence of acidity, eluting agents, stability of the column, sample volume and interfering ions has been investigated in detail. The adsorbed complex could be eluted using environmentally benign polyethylene glycol (PEG 400) and the concentration of mercury was determined by visible spectrophotometry at a wavelength maximum of 520nm. A detection limit of 4microgL(-1) could be achieved and the developed procedure was successfully applied for the determination of mercury in spiked water samples and city waste incineration ash (CRM176). The preconcentration factor attainable for quantitative recovery (>95%) of mercury(II) was 100 for a 1000mL sample volume. PMID:17572137

Rajesh, N; Gurulakshmanan, G

2008-02-01

98

Solid phase extraction and spectrophotometric determination of mercury by adsorption of its diphenylthiocarbazone complex on an alumina column  

NASA Astrophysics Data System (ADS)

A simple method has been developed for the preconcentration of mercury based on the adsorption of its diphenylthiocarbazone complex on a neutral alumina column. The influence of acidity, eluting agents, stability of the column, sample volume and interfering ions has been investigated in detail. The adsorbed complex could be eluted using environmentally benign polyethylene glycol (PEG 400) and the concentration of mercury was determined by visible spectrophotometry at a wavelength maximum of 520 nm. A detection limit of 4 ?g L -1 could be achieved and the developed procedure was successfully applied for the determination of mercury in spiked water samples and city waste incineration ash (CRM176). The preconcentration factor attainable for quantitative recovery (>95%) of mercury(II) was 100 for a 1000 mL sample volume.

Rajesh, N.; Gurulakshmanan, G.

2008-02-01

99

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

100

Modeling and Simulation the Fixed Bed Column Extraction of Inulin from Garlic ( Allium sativum L. var. Chonan)  

Microsoft Academic Search

Inulin is a fructan found in many plants as a reserve carbohydrate. It is an ingredient that integrates the group of “functional foods” improving physiological function, preventing diseases, replacing fat and sugar, and acting as a stabilizer. This work carried out the modeling and experimental data simulation obtained in the inulin extraction process from garlic in continuous flow. The extraction

Raquel M. Galante; Marintho B. Quadri; Ricardo F. Machado; Mara G. N. Quadri; Leandro Osmar Werle

2009-01-01

101

Monitoring of enzymatic hydrolysis of starch by microdialysis sampling coupled on-line to anion exchange chromatography and integrated pulsed electrochemical detection using post-column switching  

SciTech Connect

A quantitative evaluation of the hydrolysis of wheat starch using Termamyl, a thermostable {alpha}-amylase, is reported. Data from the monitoring of the hydrolysis of wheat starch indicated that, after 1 h, glucose and maltooligosaccharides up to DP 7 were the main hydrolysis products and thus enabled optimization of a liquefaction step during the production of L-lactic acid. The monitoring system used, both in the on- and off-line mode, was based on continuous flow microdialysis sampling (CFMS) coupled to anion exchange chromatography and integrated pulsed electrochemical detection (IPED). A microdialysis probe equipped with a 5-mm polysulfone (SPS 4005) membrane, with a molecular-weight cut-off of 5 kDa, was used to sample the hydrolysis products of native wheat starch at 90 C. Characteristic fingerpoint separations were achieved by anion exchange chromatography after enzymatic hydrolysis. Post-column switching improved the detection and, consequently, also quantification of the hydrolysates as fouling of the electrode could be reduced. Maltooligosaccharide standards were used for quantification and to verify the elution of the hydrolysates by spiking the off-line samples.

Torto, N.; Gorton, L.; Emneus, J.; Laurell, T. [Univ. of Lund (Sweden)] [Univ. of Lund (Sweden); Marko-Varga, G. [Astra Draco AB, Lund (Sweden). Bioanalytical Chemistry] [Astra Draco AB, Lund (Sweden). Bioanalytical Chemistry; Akerberg, C.; Zacchi, G. [Univ. of Lund (Sweden). Dept. of Chemical Engineering] [Univ. of Lund (Sweden). Dept. of Chemical Engineering; [Lund Inst. of Tech. (Sweden)

1997-12-05

102

Efficient waveguide mode extraction in white organic light emitting diodes using ITO-anodes with integrated MgF?-columns.  

PubMed

We report a simple approach to enhance the out-coupling efficiency in white organic light emitting diodes (WOLEDs). By incorporating MgF?-columns into the ITO-anode and optimizing of their geometry, an overall efficiency enhancement of up to 38% is achieved. In addition, the structuring of the anode does not lead to a change in the electrical behaviour of the devices. As evidenced by goniometric measurements, the angular emission characteristics of the WOLEDs remain unchanged. Simulations, performed with the T-matrix method, reveal the effect of the enhanced outcoupling efficiency of this approach. PMID:22418497

Bocksrocker, Tobias; Maier-Flaig, Florian; Eschenbaum, Carsten; Lemmer, Uli

2012-03-12

103

"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

104

Purification of coenzyme Q 10 from fermentation extract: High-speed counter-current chromatography versus silica gel column chromatography  

Microsoft Academic Search

High-speed counter-current chromatography (HSCCC) is applied to the purification of coenzyme Q10 (CoQ10) for the first time. CoQ10 was obtained from a fermentation broth extract. A non-aqueous two-phase solvent system composed of heptane–acetonitrile–dichloromethane (12:7:3.5, v\\/v\\/v) was selected by analytical HSCCC and used for purification of CoQ10 from 500mg of the crude extract. The separation yielded 130mg of CoQ10 at an

Xue-Li Cao; Ya-Tao Xu; Guang-Ming Zhang; Sheng-Meng Xie; Ying-Mao Dong; Yoichiro Ito

2006-01-01

105

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

106

The QUISTOR as a pulsed-extraction source for time-of-flight mass spectrometry of VOCs in air  

SciTech Connect

Recently, the authors have been developing the ion trap/time-of-flight mass spectrometer (IT/TOF-MS) as a new instrument for real-time air analysis. The ion trap is an attractive pulsed-extraction source for TOF-MS because of its ion storage capability and its potential for high extraction efficiencies. In the IT/TOF-MS ion trap the entire ion cloud is extracted toward the exit endcap, as compared to 50% in an ion trap mass spectrometer. Moreover, the ion trap pulsed-extraction source can tolerate high background pressures and excessive space charge. The work presented here focuses on the development of the ion trap to improve the overall performance of the IT/TOF-MS used for air monitoring. A number studies have been performed to determine the best conditions for extraction of the ion cloud with the proper spatial and velocity distributions for focusing in the TOF-MS. Results from these investigations have led to improvements in ion trap operation. Detection limits are generally in the low to sub-ppb (V/V) range for analysis between times 10 and 100 ms. Resolution exceeds 2000 m/{Delta}m at FWHM. Mass accuracy is routinely 0.05% and scan-to-scan variations are less than 5%.

Chambers, D.M.; Thomas, S.W.; Grace, L.I.; Andresen, B.D. [Lawrence Livermore National Lab., CA (United States)

1995-12-31

107

In vitro inhibition and dissolution of calcium oxalate by edible plant Trianthema monogyna and pulse Macrotyloma uniflorum extracts  

NASA Astrophysics Data System (ADS)

Edible plant Trianthema monogyna (TME) and the pulse Macrotyloma uniflorum (KPE) extracts were found to be effective in the inhibition of calcium oxalate crystallization. Various physicochemical techniques, viz. conductometric and nephelometric titrations, UV-vis and IR spectroscopy and potential measurements in the absence and presence of these extracts were employed. TME and KPE both reduced the particle size considerably from 250 to 5-50 ?m range as revealed by microphotographs. Considerable solubility in the presence of TME and KPE was also observed by flame photometric studies. Dissolution was found to vary with time. Particle size distribution in CaC 2O 4 precipitate may be one of the reasons.

Das, Ishwar; Gupta, S. K.; Ansari, Shoeb A.; Pandey, V. N.; Rastogi, R. P.

2005-01-01

108

Solid phase extraction of chromium(VI) from aqueous solutions by adsorption of its diphenylcarbazide complex on a mixed bed adsorbent (acid activated montmorillonite-silica gel) column.  

PubMed

A novel approach has been developed for the solid phase extraction of chromium(VI) based on the adsorption of its diphenylcarbazide complex on a mixture of acid activated montmorillonite (AAM)-silica gel column. The effect of various parameters such as acidity, stability of the column, sample volume, interfering ions, etc., were studied in detail. The adsorbed complex could be easily eluted using polyethylene glycol-sulfuric acid mixture and the concentration of chromium has been determined using visible spectrophotometry. The calibration graph was linear in the range 0-1microgmL(-1) chromium(VI) with a detection limit of 6microgL(-1). A highest preconcentration factor of 25 could be obtained for 250mL sample volume using glass wool as support for the mixed bed adsorbent. Chromium(VI) could be effectively separated from other ions such as nickel, copper, zinc, chloride, sulfate, nitrate, etc., and the method has been successfully applied to study the recovery of chromium in electroplating waste water and spiked water samples. PMID:17604681

Rajesh, N; Mishra, Braja Gopal; Pareek, Pawan Kumar

2008-02-01

109

Solid phase extraction of chromium(VI) from aqueous solutions by adsorption of its diphenylcarbazide complex on a mixed bed adsorbent (acid activated montmorillonite-silica gel) column  

NASA Astrophysics Data System (ADS)

A novel approach has been developed for the solid phase extraction of chromium(VI) based on the adsorption of its diphenylcarbazide complex on a mixture of acid activated montmorillonite (AAM)-silica gel column. The effect of various parameters such as acidity, stability of the column, sample volume, interfering ions, etc., were studied in detail. The adsorbed complex could be easily eluted using polyethylene glycol-sulfuric acid mixture and the concentration of chromium has been determined using visible spectrophotometry. The calibration graph was linear in the range 0-1 ?g mL -1 chromium(VI) with a detection limit of 6 ?g L -1. A highest preconcentration factor of 25 could be obtained for 250 mL sample volume using glass wool as support for the mixed bed adsorbent. Chromium(VI) could be effectively separated from other ions such as nickel, copper, zinc, chloride, sulfate, nitrate, etc., and the method has been successfully applied to study the recovery of chromium in electroplating waste water and spiked water samples.

Rajesh, N.; Mishra, Braja Gopal; Pareek, Pawan Kumar

2008-02-01

110

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

111

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

112

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

113

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

114

Petroleum mass removal from low permeability sediment using air sparging/soil vapor extraction: impact of continuous or pulsed operation  

NASA Astrophysics Data System (ADS)

Air sparging and soil vapor extraction (AS/SVE) are innovative remediation techniques that utilize volatilization and microbial degradation to remediate petroleum spills from soils and groundwater. This in situ study investigated the use of AS/SVE to remediate a gasoline spill from a leaking underground storage tank (UST) in the low permeability, clayey soil of the Appalachian Piedmont. The objectives of this study were to evaluate AS/SVE in low permeability soils by quantifying petroleum mass removal rates, monitoring vadose zone contaminant levels, and comparing the mass extraction rates of continuous AS/SVE to 8 and 24 h pulsed operation. The objectives were met by collecting AS/SVE exhaust gas samples and vadose zone air from multi-depth soil vapor probes. Samples were analyzed for O 2, CO 2, BTEX (benzene, toluene, ethylbenzene, xylene), and total combustible hydrocarbon (TCH) concentrations using portable hand meters and gas chromatography. Continuous AS/SVE was effective in removing 608 kg of petroleum hydrocarbons from low permeability soil in 44 days (14.3 kg day -1). Mass removal rates ranged from 2.6 times higher to 5.1 times lower than other AS/SVE studies performed in sandy sediments. BTEX levels in the vadose zone were reduced from about 5 ppm to 1 ppm. Ten pulsed AS/SVE tests removed 78 kg in 23 days and the mean mass removal rate (17.6 kg day -1) was significantly higher than the last 15 days of continuous extraction. Pulsed operation may be preferable to continuous operation because of increased mass removal and decreased energy consumption.

Kirtland, Brian C.; Aelion, C. Marjorie

2000-02-01

115

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

116

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

117

Study of longitudinal mixing in pulse columns 0. 057-1. 5 m in diameter with distributed packings in the case of low-velocity solution and pulp flows  

SciTech Connect

The authors present results on the hydraulics of one- and two-phase flows for counterflow pulse columns in regard to the conditions found in hydrometallurgy and leaching operations. They contend that the efficiency of such units can be calculated and hence optimized if the longitudinal mixing coefficients are available; to this end; they determine these coefficients mathematically as well as from curves obtained from the response of the system to the pulsed introduction of the following indicators: a solution of methylene blue, sodium chloride, chloroauric acid labeled with gold 198 and sodium iodide labeled with the iodine 131 isotope, and a solid phase irradiated in the reactor with neutrons with induction of the iron 55 isotope.

Zakharov, E.I.; Roshchin, D.V.; Levchenko, A.L.; Kobzev, V.V.; Shabanov, A.I.; Kiselev, V.N.

1986-09-20

118

Trajan's Column  

NSDL National Science Digital Library

This Website, from McMaster University, uses the combined skills of artists, writers, programmers, and Web designers to create a resource for the study of Trajan's column, a Roman architectural monument. This 100-foot marble column, built during the reign of Emperor Trajan, 98-117 AD, is topped with a gilded statue of Trajan and decorated with carvings recounting Trajan's rule, primarily the Dacian Wars and his building projects. The heart of the Website is the database of 500 slides of the carvings; indexes allow users to view the slides in thematic groupings such as images of sides of the column, groups organized by subject keywords, or carvings made with specific tools. Cartoons or drawings of the column help to contextualize the details found in the slides, and essays provide more information on its design, construction, and preservation.

119

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

120

Testing a prototype pulse generator for a continuous flow system and its use for E. coli inactivation and microalgae lipid extraction.  

PubMed

Among other applications, electroporation is used for the inactivation of pathogens and extraction of substances from microorganisms in liquids where large scale flow systems are used. The aim of our work was therefore to test a pulse generator that enables continuous pulsed electric field (PEF) treatment for Escherichia coli inactivation and microalgae lipid extraction. In the continuous flow PEF system, the flow rate was adjusted so that each bacterial cell received a defined number of pulses. The results of PEF flow treatment showed that the number of pulses influences E. coli inactivation to the same extent as in the previously described cuvette system, i.e., batch system. The continuous flow PEF system was also tested and evaluated for lipid extraction from microalgae Chlorella vulgaris. In control experiments, lipids were extracted via concentration of biomass, drying and cell rupture using pressure or an organic solvent. In contrast, electroporation bypasses all stages, since cells were directly ruptured in the broth and the oil that floated on the broth was skimmed off. The initial experiments showed a 50% oil yield using the electroporation flow system in comparison to extraction with organic solvent. PMID:24713586

Flisar, Karel; Meglic, Sasa Haberl; Morelj, Jernej; Golob, Janvit; Miklavcic, Damijan

2014-12-01

121

Time-varying autoregressive model-based multiple modes particle filtering algorithm for respiratory rate extraction from pulse oximeter.  

PubMed

We present a particle filtering algorithm, which combines both time-invariant (TIV) and time-varying autoregressive (TVAR) models for accurate extraction of breathing frequencies (BFs) that vary either slowly or suddenly. The algorithm sustains its robustness for up to 90 breaths/min (b/m) as well. The proposed algorithm automatically detects stationary and nonstationary breathing dynamics in order to use the appropriate TIV or TVAR algorithm and then uses a particle filter to extract accurate respiratory rates from as low as 6 b/m to as high as 90 b/m. The results were verified on 18 healthy human subjects (16 for metronome and 2 for spontaneous measurements), and the algorithm remained accurate even when the respiratory rate suddenly changed by 24 b/m (either increased or decreased by this amount). Furthermore, simulation examples show that the proposed algorithm remains accurate for SNR ratios as low as -20 dB. We are not aware of any other algorithms that are able to provide accurate TV BF over a wide range of respiratory rates directly from pulse oximeters. PMID:20937577

Lee, Jinseok; Chon, Ki H

2011-03-01

122

Olive oil pilot-production assisted by pulsed electric field: Impact on extraction yield, chemical parameters and sensory properties.  

PubMed

The impact of the use of pulsed electric field (PEF) technology on Arroniz olive oil production in terms of extraction yield and chemical and sensory quality has been studied at pilot scale in an industrial oil mill. The application of a PEF treatment (2kV/cm; 11.25kJ/kg) to the olive paste significantly increased the extraction yield by 13.3%, with respect to a control. Furthermore, olive oil obtained by PEF showed total phenolic content, total phytosterols and total tocopherols significantly higher than control (11.5%, 9.9% and 15.0%, respectively). The use of PEF had no negative effects on general chemical and sensory characteristics of the olive oil, maintaining the highest quality according to EU legal standards (EVOO; extra virgin olive oil). Therefore, PEF could be an appropriate technology to improve olive oil yield and produce EVOO enriched in human-health-related compounds, such as polyphenols, phytosterols and tocopherols. PMID:25149017

Puértolas, Eduardo; Martínez de Marañón, Iñigo

2015-01-15

123

A core-shell column approach to a comprehensive high-performance liquid chromatography phenolic analysis of Vitis vinifera L. and interspecific hybrid grape juices, wines, and other matrices following either solid phase extraction or direct injection.  

PubMed

Four high-throughput reverse-phase chromatographic protocols utilizing two different core-shell column chemistries have been developed to analyze the phenolic profiles of complex matrices, specifically targeting juices and wines produced from interspecific hybrid grape cultivars. Following pre-fractionation via solid-phase extraction or direct injection, individual protocols were designed to resolve, identify and quantify specific chemical classes of compounds including non-anthocyanin monomeric phenolics, condensed tannins following acid hydrolysis, and anthocyanins. Detection levels ranging from 1.2 ppb to 27.5 ppb, analyte %RSDs ranging from 0.04 to 0.38, and linear ranges of quantitation approaching five orders of magnitude were achieved using conventional HPLC instrumentation. Using C(18) column chemistry, the non-anthocyanin monomeric protocol effectively separated a set of 16 relevant phenolic compounds comprised flavan-3-ols, hydroxycinnamic acids, and flavonols in under 14 min. The same column was used to develop a 15-min protocol for hydrolyzed condensed tannin analysis. Two anthocyanin protocols are presented, one utilizing the same C(18) column, best suited for anthocyanidin and monoglucoside analysis, the other utilizing a pentafluorophenyl chemistry optimized to effectively separate complex mixtures of coexisting mono- and diglucoside anthocyanins. These protocols and column chemistries have been used initially to explore a wide variety of complex phenolic matrices, including red and white juices and wines produced from Vitis vinifera and interspecific hybrid grape cultivars, juices, teas, and plant extracts. Each protocol displayed robust matrix responses as written, yet are flexible enough to be easily modified to suit specifically tailored analytical requirements. PMID:22771069

Manns, David C; Mansfield, Anna Katharine

2012-08-17

124

Simultaneous determination of glucose, D-gluconic, 2-keto-D-gluconic and 5-keto-D-gluconic acids by ion chromatography-pulsed amperometric detection with column-switching technique.  

PubMed

A simple ion chromatographic (IC) method for simultaneous determination of glucose, D-gluconic acid (DGA), 2-keto-D-gluconic acid (2-KDG) and 5-keto D-gluconic acid (5-KDG) was proposed, with pulsed amperometric detection (PAD) and column-switching technique. Using this technique, the four compounds were detected simultaneously in a short time with strongly retained compounds (2-KDG and 5-KDG) eluted out prior to weakly retained compounds (glucose and DGA). Under the optimized conditions, the method showed good linearity in the range of 0.01-20 mg L(-1) with determination coefficients (R(2))? 99.84%. Low detection limits (LODs) in the range of 0.87-2.59 ?g L(-1) and good repeatability (RSD<3%, n=6) were obtained. The proposed method has been successfully applied to the analysis of the four compounds in the fermentation broth, in which Gluconobacter oxydans was used to produce gluconic acids from glucose. PMID:23708631

Zhu, Zuoyi; Xi, Lingling; Subhani, Qamar; Huang, Zhongping; Zhu, Yan

2013-09-15

125

High-Efficiency On-Line SolidPhase Extraction Coupling to 15-150 um I.D. Column Liquid Chromatography for Proteomic Analysis  

Microsoft Academic Search

Flexible manipulation of various properties of proteomic samples is important for proteomic analyses, but it has been little explored for newly developed approaches based on liquid chromatography (LC) in combination with mass spectrometry (MS). With miniaturization of the LC column inner diameter dimensions (required for improving the analysis sensitivity), this issue becomes more challenging due to the small flow rates

Yufeng Shen; Ronald J. Moore; Rui Zhao; Josip Blonder; Deanna L. Auberry; Christophe D. Masselon; Ljiljana Pasa Tolic; Kim K. Hixson; Kenneth J. Auberry; Richard D. Smith

2003-01-01

126

Deparaffinization and lysis by hydrothermal pressure (pressure cooking) coupled with chaotropic salt column purification: a rapid and efficient method of DNA extraction from formalin-fixed paraffin-embedded tissue.  

PubMed

We report a hydrothermal pressure method (pressure cooking) for simultaneous deparaffinization and lysis of formalin-fixed paraffin-embedded tissue followed by conventional chaotropic salt column purification to obtain high-quality DNA. Using this method, the release of DNA occurred within the first minute of treatment, reaching the maximum at 5 minutes. An optimal treatment window was between 5 and 30 minutes. The extracted DNA was of high quality as determined by the 260/280 absorbance ratios, and the quantity of DNA extracted was linear with the input tissue amount. In paired sample experiments (N=19), the quantity of DNA extracted by hydrothermal pressure treatment was comparable to that obtained through the conventional xylene deparaffinization and protease K digestion method. The integrity of the recovered DNA was also comparable, evidenced by polymerase chain reaction amplifications of variable-sized amplicons in tissue samples archived from 0.2 to 22 years (N=14). The high quality of DNA was further confirmed by polymerase chain reaction amplification and Sanger sequencing analysis of representative exons of the EGFR gene in human non-small cell lung cancer tissue samples. In summary, this novel method offers DNA release from formalin-fixed paraffin-embedded tissue with unprecedented simplicity, speed, biohazard safety, and cost-efficiency. Combined with chaotropic salt column purification, high-quality DNA can be prepared for downstream applications in <30 minutes. PMID:23370427

Zhong, Haohao; Liu, Yan; Talmor, Monica; Wu, Bingquan; Hui, Pei

2013-03-01

127

One-way and two-way pulsed electromembrane extraction for trace analysis of amino acids in foods and biological samples.  

PubMed

In the present work, pulsed electromembrane extraction (PEME) was performed for the first time, as a new concept of electrically enhanced microextraction method, for extraction and quantification of histidine, phenylalanine and tryptophan in different matrices. PEME offers an alternative to conventional electromembrane extraction (EME), which faces problems such as serious instabilities in the analysis of real samples with high concentration levels of ions. In these samples, increasing of the ion transportation across the liquid membrane results in Joule heating during the extraction process which may follow by punctuation of the organic membrane, increasing of the current level and bubble formation due to electrolysis reactions. A mixture of 2-nitrophenyl octyl ether (NPOE), di-(2-ethylhexyl) phosphate (DEHP) and tris-(2-ethylhexyl) phosphate (TEHP) was immobilized in the pores of hollow fiber as the organic liquid membrane. Other effective parameters such as extraction time, ion balance and pulse frequency were optimized using the experimental design. Extraction recoveries in the range of 7.1-21.6% and satisfactory repeatability (2.1extraction (EME), which proves the advantages of the proposed technique. The method was applied to the determination and quantification of amino acids in foods and biological samples. Also, two-way PEME was employed as a novel approach for highly selective extraction of tryptophan as a model analyte to introduce an interesting ability of the proposed technique. PMID:23561906

Rezazadeh, Maryam; Yamini, Yadollah; Seidi, Shahram; Esrafili, Ali

2013-04-22

128

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

129

DNA Spin Columns Regular Spin Columns  

E-print Network

or bubbles. 1. Remove tip of Bio-Rad column. Place column in 13 X 100 mm glass tube in rack. Fill column centrifuge with swing-out rotor. Plastic Syringes Prepare syringes as follows. Cut circles of GF/C (glass

Aris, John P.

130

Investigation of Pulsed Electric Field (PEF) as an Intensification Pretreatment for Solvent Lipid Extraction from Microalgae, utilizing Ethyl Acetate as a Greener Substitute to Chloroform-based Extraction  

E-print Network

two significant challenges: green solvent selection with efficient extractive characteristics and requirement of cell disruption pretreatment. In this contribution, the utilization of ethyl acetate-based solvents is suggested as a green alternative...

Antezana Zbinden, Mauricio Daniel R.

2011-02-16

131

Zenix SEC Column Manual Column Information  

E-print Network

1 Zenix SEC Column Manual Column Information Utilizing proprietary surface technologies and 3 m. They are compatible with most aqueous buffers, such as ammonium acetate, phosphate, tris, etc. When 150 mM phosphate phase: 150 mM Sodium Phosphate Buffer, pH 7 Flow rate: 1.0 mL/min Temperature: Ambient (~23° C

Lebendiker, Mario

132

Dynamic NMR microscopy of chromatographic columns  

Microsoft Academic Search

Pulsed magnetic field gradients encoded a discrete spatial and temporal motion of the molecules of a fluid percolating through the packed bed of a dynamic radial compression column for liquid chromatography. Two packing materials of porous, chemically bonded C18 silica were used; large irregularly shaped particles (55--105 μm) and small spherical particles (6 μm). By combining pulsed field gradient NMR

Ulrich Tallarek; Ernst Bayer; Dagmar Van Dusschoten; T. W. J. Scheenen; Henk Van As; Georges Guiochon; Uwe D. Neue

1998-01-01

133

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

134

Five points on columns  

E-print Network

“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 ...

Rockland, Kathleen

135

JCE Feature Columns  

Microsoft Academic Search

The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using

Jon L. Holmes

1999-01-01

136

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

137

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

138

Inelastic column behavior  

NASA Technical Reports Server (NTRS)

The significant findings of a theoretical study of column behavior in the plastic stress range are presented. When the behavior of a straight column is regarded as the limiting behavior of an imperfect column as the initial imperfection (lack of straightness) approaches zero, the departure from the straight configuration occurs at the tangent-modulus load. Without such a concept of the behavior of a straight column, one is led to the unrealistic conclusion that lateral deflection of the column can begin at any load between the tangent-modulus value and the Euler load, based on the original elastic modulus. A family of curves showing load against lateral deflection is presented for idealized h-section columns of various lengths and of various materials that have a systematic variation of their stress-strain curves.

Duberg, John E; Wilder, Thomas W , III

1952-01-01

139

Application of a fully thermally coupled distillation column for fractionation process in naphtha reforming plant  

Microsoft Academic Search

Naphtha reformate is extracted for aromatic compounds and the aromatics are separated into benzene, toluene and xylene in sequence. This separation is conducted using a series of binary-like columns.In this study, the first two columns of the separation process are replaced with a fully thermally coupled distillation column (FTCDC) also known as the Petlyuk column. Though feed of the process

Ju Yeong Lee; Young Han Kim; Kyu Suk Hwang

2004-01-01

140

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

141

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

142

Medial column stabilization.  

PubMed

This article presented a brief review of medial column stabilizing procedures. The various types of procedures that have been advocated for different deformities have been discussed. It is important to keep in mind that fusion of any of the medial column joints should not be performed as an isolated procedure in flexible flatfoot deformity. Medial column stabilization is only a component procedure when surgically managing a flexible flatfoot. When choosing procedures to correct a flexible flatfoot, thorough preoperative evaluation is important. It is also important to realize that conservative measures should be exhausted before attempting any type of stabilization of the medial column for flexible flatfoot deformity. Specific criteria for flexible flatfoot surgery should include severe uncontrollable deformity, an inability to wear standard foot gear, and persistent pain and disability despite exhaustive conservative therapy. A medial column stabilization is also an excellent procedure for those patients who have end-stage degenerative joint disease of the medial longitudinal arch. PMID:1893342

Catanzariti, A R

1991-07-01

143

JCE Feature Columns  

NASA Astrophysics Data System (ADS)

The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad in the Chemistry Curriculum, and WWW Site Review. These columns differ from the print feature columns in that they use the Internet as the publication medium. Doing so allows these features to include continually updated information, digital components, and links to other online resources. The Conceptual Questions and Challenge Problems feature of JCE Internet serves as a good example for the kinds of resources that you can expect to find in an online feature column. Like other columns it contains a mission statement that defines the role of the column. It includes a digital library of continually updated examples of conceptual questions and challenge problems. (As I write this we have just added several new questions to the library.) It also includes a list of links to related online resources, information for authors about how to write questions and problems, and information for teachers about how to use conceptual questions and challenge problems. Teaching with Technology home page at JCE Online. One-Stop Feature Shop The updated Feature area of JCE Online offers information about all JCE feature columns in one place. It gives you a quick and convenient way to access a group of articles in a particular subject area. It provides authors and readers with a good definition of the column and its mission. It complements the print feature columns with online resources. It provides up-to-date bibliographies for selected areas of interest. And last, but not least, it provides that email address you can use to send that message of appreciation to the feature editor for his or her contribution to JCE and the chemical education community.

Holmes, Jon L.

1999-05-01

144

Water vapor column abundance retrievals during FIFE  

Microsoft Academic Search

This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. The authors report on the use of a sunphotometer to extract column

C. J. Bruegge; J. E. Conel; R. O. Green; J. S. Margolis; R. G. Holm; G. Toon

1992-01-01

145

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

146

False identification of urinary ephedrine as methamphetamine by gas chromatography/mass spectrometry with a DB-17 column.  

PubMed

A 17-year-old motorcyclist was killed in a traffic accident. The urine sample collected at autopsy was screened by the Toxi-Lab system; it showed a possible presence of either methamphetamine (MA) or ephedrine (Eph). Gas chromatography-mass spectrometry (GC-MS) was carried out for a trifluoroacetyl (TFA)-derivatized sample after extraction with an Extrelut column. A peak was detected at the same retention time as that of the authentic Eph by GC-MS with a DB-17 wide-bore column; the mass spectrum of the peak was, however, very similar to that of MA. The presence of Eph and absence of MA were proved by GC-MS using a DB-1 column. The Eph in the urine was further confirmed by high performance liquid chromatography (HPLC)-MS using an ODS column. By the REMEDi HS system, Eph and methylephedrine were determined in the urine, and their concentrations (hydrochloride salt) were 0.752 and 2.13 micrograms/ml, respectively. Ethanol was detected as well in the blood (1.55 mg/ml) and urine (2.01 mg/ml) by a pulse heating method. Nicotine, caffeine and dihydrocodeine were also qualitatively detected in the urine by Toxi-Lab, HPLC-MS and REMEDi HS systems. The present case warned that urinary Eph can be misidentified as MA by GC-MS with an intermediately polar column after TFA derivatization. PMID:9301231

Takayasu, T; Ohshima, T; Ohtsuji, M; Takayama, N; Kondo, T; Lin, Z; Sato, Y; Minamino, T

1997-06-01

147

Eruption column physics  

SciTech Connect

In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

Valentine, G.A.

1997-03-01

148

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

149

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

150

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

151

Rapid Column Extraction method for SoilRapid Column Extraction method for Soil  

Microsoft Academic Search

The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign}

Brian K. Culligan

2005-01-01

152

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

153

Combination of off-line solid-phase extraction and on-column sample stacking for sensitive determination of parabens and p-hydroxybenzoic acid in waters by non-aqueous capillary electrophoresis  

Microsoft Academic Search

For the first time, a procedure based on solid-phase extraction (SPE) for the simultaneous extraction of a group of parabens (methyl, ethyl, propyl, butyl and benzyl p-hydroxybenzoates) and p-hydroxybenzoic acid (PHBA), from environmental water samples has been developed. Analysis of the extracts was performed by non-aqueous capillary electrophoresis (NACE) coupled with diode array detection (DAD), using large-volume sample stacking (LVSS)

Eva Blanco; María del Carmen Casais; María del Carmen Mejuto; Rafael Cela

2009-01-01

154

CHARACTERIZATION OF THE DOWNFLOW SECTION OF AN AIRLIFT COLUMN USING BUBBLE SIZE DISTRIBUTION MEASUREMENTS  

Microsoft Academic Search

Bubble size distributions in an airlift column were investigated with an emphasis on the downflow section. Measurements have been made using direct photographic techniques in conjunction with image analysis in a split cylinder airlift column. Information extracted from these measurements includes local gas hold-up, variation of Sauter mean bubble diameter with column length, and liquid circulation velocity. An air-tap water

SNEHAL A. PATEL; L. A. GLASGOW; L. E. ERICKSON; C. H. LEE

1986-01-01

155

Automated solid-phase extraction and coupled-column reversed-phase liquid chromatography for the trace-level determination of low-molecular-mass carbonyl compounds in air  

Microsoft Academic Search

This study reports the development of a coupled-column RPLC method for the trace level determination of several volatile aldehydes in ambient air. Carbonyls in air are sampled using a ozone scrubber and SPE C18 cartridges which are pretreated with 2,4-dinitrophenylhydrazone. The method is used for the separation of 13 different aldehydes and ketones. All analytes are separated without high blanks

P. R. Kootstra; H. A. Herbold

1995-01-01

156

Modeling chromatographic columns  

Microsoft Academic Search

In this work a new mathematical model, based on non-equilibrium conditions, describing the dynamic adsorption of proteins in columns packed with spherical adsorbent particles is used to study the performance of chromatographic systems. Simulations of frontal chromatography, including axial dispersion, for non-equilibrium systems with non-linear adsorption isotherms are made and compared to those of the experimentally determined protein A affinity

Ahmet R Özdural; Asl? Alkan; Piet J. A. M Kerkhof

2004-01-01

157

CFRP Prestressed Concrete Lighting Columns  

E-print Network

Aspects of the design and installation of a novel carbon fibre reinforced polymer (CFRP) prestressed high strength concrete lighting column (Carbolith®) are presented. The tapered cylindrical columns have a nominal height of 8 m and contain...

Terrasi, Giovanni P.; Lees, Janet M.

2003-08-01

158

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

159

Analysis of phenolic compounds in effluent by solid-phase extraction and gas chromatography-mass spectrometry with direct on-column benzylation: sensitive negative ion chemical ionisation gas chromatography-mass spectrometry detection of phenyl benzyl ethers  

Microsoft Academic Search

A procedure for the extraction of eight phenolic compounds in effluent from various tertiary sewerage treatment plants in the Sydney area using a non-ionic polystyrene-divinylbenzene polymeric sorbent is described. Good recoveries were obtained for these phenols which differ widely in polarity. The performance of this new sorbent is superior to that of graphitised carbon black. The determination of the phenols

Julie Cheung; Robert J. Wells

1997-01-01

160

Determination of cyclodextrins in serum by reversed-phase chromatography with pulsed amperometric detection and a membrane reactor.  

PubMed

A high-performance liquid chromatographic method has been developed for the determination of cyclodextrins (CDs) in serum. The method involves solid-phase extraction of CDs, separation on a C18 reversed-phase column using a mixture of water, tetrahydrofuran and methanol as an eluent, eluent pH modification with a cation-exchange membrane reactor surrounded by 1.5 M sodium hydroxide solutions, and pulsed amperometric detection (PAD) with a gold working electrode. The solid-phase extraction on a C18 bonded-silica column was effective for removing the PAD sensitive components in serum. The calibration graphs constructed by internal standard method were linear over the range 6.25-200 pmol of CDs in serum. The detection limits for CDs were about 5 pmol at a signal-to-noise ratio of 3. PMID:8305583

Haginaka, J; Nishimura, Y; Yasuda, H

1993-10-01

161

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

162

Density Column Lab - Part 2  

NSDL National Science Digital Library

Concluding a two-part lab activity, students use triple balance beams and graduated cylinders to take measurements and calculate densities of several household liquids and compare them to the densities of irregularly shaped objects (as determined in Part 1). Then they create density columns with the three liquids and four solid items to test their calculations and predictions of the different densities. Once their density columns are complete, students determine the effect of adding detergent to the columns. After this activity, present the associated Density & Miscibility lesson for a discussion about why the column layers do not mix.

GK-12 Program,

163

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

164

Zenix-C SEC Column User Manual Column Information  

E-print Network

1 Zenix-C SEC Column User Manual Column Information Utilizing proprietary surface technologies stability. They are compatible with most aqueous buffers, such as ammonium acetate, phosphate, tris, etc µm, 7.8x300 mm) Mobile phase: 150 mM Sodium Phosphate, pH 7.0 Flow rate: 1.0 mL/min Detection: UV214

Lebendiker, Mario

165

A combined liquid three-phase micro-extraction and differential pulse voltammetric method for preconcentration and detection of ultra-trace amounts of buprenorphine using a modified pencil electrode.  

PubMed

A combination of polytetrafluorethylene membrane-based liquid three-phase micro-extraction and voltammetry was used for the micro-separation and determination of buprenorphine. Type of the organic solvent used, pH levels of the donor and acceptor phases, salt concentration, extraction time, stirring rate, and electrochemical parameters as the essential factors affecting the liquid three-phase micro-extraction of buprenorphine were investigated. Differential pulse voltammetry exhibited two linear dynamic ranges of 1.0-109.0 pmol L(-1) and 0.109 nmol L(-1)-0.11 µmol L(-1) of buprenorphine and the detection limit was found to be as low as 0.6 pmol L(-1) of buprenorphine. Also, the effects of a number of common substances potentially interfering with selectivity were studied. The results indicate that the proposed method is highly selective and sensitive for buprenorphine detection in real samples such as human urine and plasma of both drug-addict and non-addict human subjects. PMID:24148523

Ensafi, Ali A; Khoddami, Elaheh; Rezaei, B

2013-11-15

166

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

167

This column will self destruct  

Microsoft Academic Search

Purpose – This column aims to focus on the obsolescence of technology, and the problems associated with the archiving, storage and retrieval of data. Design\\/methodology\\/approach – The column takes the form of a viewpoint paper. Findings – All technology is susceptible to obsolescence, meaning that information can be lost due to changes in hardware and software. A book or printed

John Maxymuk

2010-01-01

168

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

169

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

170

Hybrid monolithic columns with nanoparticles incorporated for capillary electrochromatography.  

PubMed

The core-shell silica nanoparticles Fe(3)O(4)@SiO(2)/NH(2), wormlike and hexagonal SBA-15 silica were incorporated into polymethacrylate monolithic columns containing butyl methacrylate (BMA) and ethylene dimethacrylate (EDMA), respectively to develop novel stationary phases with mixing mechanism of reverse phase and ion exchange. Experimental conditions including types of nanoparticles, dispersion pattern, nanoparticles concentration, column placement mode, and reaction temperature were optimized for simple and stable column preparation. The poly(BMA-EDMA-Fe(3)O(4)@SiO(2)/NH(2)) and poly(BMA-EDMA-SBA-15/NH(2)) (both wormlike and hexagonal shape nanoparticles) monolithic columns were evaluated with mixture of organic acids as sample in capillary electrochromatography (CEC) mode and the relative column efficiency reaches 290,000plates/m. The results indicate that the incorporation of nanoparticles with various shapes enhances both selectivity and column efficiency due to high specific surface area of nanoparticles and mixing separation mechanism. In addition, poly(BMA-EDMA-Fe(3)O(4)@SiO(2)/NH(2)) monolith capillary column was applied to separation of aqueous extract of rhizoma gastrodiae and showed great potential in the method development of complex samples. PMID:22503585

Lei, Wen; Zhang, Ling-Yi; Wan, Li; Shi, Bian-Fang; Wang, Yan-Qin; Zhang, Wei-Bing

2012-05-25

171

Object extraction Object extraction  

E-print Network

Object extraction #12;Object extraction · Extracting topographic objects from images · the main goal of aerial photogrammetry · object extraction consists of two steps · image interpretation extraction · Extracting topographic objects from images · identify all objects of a certain class · measure

Giger, Christine

172

EXPERIMENTAL INVESTIGATION ON THE AMBIPOLAR EFFUSION FROM THE POSITIVE COLUMN  

Microsoft Academic Search

In an effusion method for ion extraction from the positive column in a ; low-pressure gas discharge in which the use of metal parts and voltage ; fluctuations inside the plasma was avoided, the ion effusion current was ; determined in the undisturbed plasma. Measured effusion currents (some 10⁻⁹; amp) from a helium discharge with different discharge current strengths (1.5

Weimer

1958-01-01

173

Chapter 24 Protein Chromatography on Hydroxyapatite Columns  

Microsoft Academic Search

The introduction of spherical forms of hydroxyapatite has enabled protein scientists to separate and purify proteins multiple times with the same packed column. Biopharmaceutical companies have driven single column applications of complex samples to simpler samples obtained from upstream column purification steps on affinity, ion exchange or hydrophobic interaction columns. Multiple column purification permits higher protein loads to spherical forms

Larry J. Cummings; Mark A. Snyder; Kimberly Brisack

2009-01-01

174

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

175

Extraction of aflatoxins from food samples using graphene-based magnetic nanosorbents followed by high-performance liquid chromatography: a simple solution to overcome the problems of immunoaffinity columns.  

PubMed

In this research, magnetic graphene nanoparticles were prepared and used as adsorbents for preconcentrating the aflatoxins in rice, wheat, and sesame samples. For this purpose, graphene was synthesized by Hummer's method. Magnetically modified graphene formed by the deposition of magnetite (Fe3O4) on graphene was used for the separation of aflatoxins B1, B2, G1, and G2 from the samples. The extractants were subsequently analyzed with high-performance liquid chromatography and fluorescence detection. Parameters affecting the efficiency of the method were thoroughly investigated. The measurements were done under the optimized conditions. For aflatoxins B1, B2, G1, and G2, limits of detection were 0.025, 0.05, 0.05, and 0.075 ng/g and limits of quantification were 0.083, 0.16, 0.16, and 0.23 ng/g, respectively. Accuracy was examined by the determination of the relative recovery of the aflatoxins. The relative recovery of aflatoxins B1, B2, G1, and G2 were quite satisfactory (between 64.38 and 122.21% for food samples). Relative standard deviations for within laboratory repeatability (n = 6) were in the range from 1.3 to 3.2. The application of this sorbent for the separation and concentration of the mentioned aflatoxins from food samples was examined. PMID:24975571

Es'haghi, Zarrin; Beheshti, Hamed Reza; Feizy, Javad

2014-09-01

176

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

177

Use of specially designed columns for antioxidants and antimicrobials enrichment by preparative supercritical fluid chromatography  

Microsoft Academic Search

A new, specially designed column has been developed for fractionation of supercritical fluid extract of rosemary by using a preparative supercritical fluid chromatography system (Prep-SFC). The column evaluated in this work was prepared using a new packing method consisting of a combination of slurry and supercritical CO2 with commercial silica particles coated with a stationary phase commonly used in gas

Pilar Ramírez; Susana Santoyo; Mónica R. García-Risco; F. Javier Señoráns; Elena Ibáñez; Guillermo Reglero

2007-01-01

178

Pulse stretcher  

DOEpatents

Apparatus for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse is disclosed. The apparatus uses a White cell having a plurality of optical delay paths of successively increasing number of passes between the field mirror and the objective mirrors. A pulse from a laser travels through a multi-leg reflective path between a beam splitter and a totally reflective mirror to the laser output. The laser pulse is also simultaneously injected through the beam splitter to the input mirrors of the optical delay paths. The pulses from the output mirrors of the optical delay paths go simultaneously to the laser output and to the input mirrors of the longer optical delay paths. The beam splitter is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output. 6 figures.

Horton, J.A.

1994-05-03

179

Selected Topics in Column Generation  

E-print Network

Dec 2, 2002 ... Dantzig-Wolfe decomposition and column generation, devised for linear programs, is a success ... To appear in Operations Research. ... damental idea, developing a strategy to extend a linear program columnwise as needed ...

2002-12-02

180

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

181

Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments  

EPA Science Inventory

Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

182

Pulse Voltammetry  

NASA Astrophysics Data System (ADS)

The idea of imposing potential pulses and measuring the currents at the end of each pulse was proposed by Barker in a little-known journal as early as in 1958 [1]. However, the first reliable trouble-free and affordable polarographs offering voltammetric pulse techniques appeared on the market only in the 1970s. This delay was due to some limitations on the electronic side. In the 1990s, again substantial progress in electrochemical pulse instrumentation took place. This was related to the introduction of microprocessors, computers, and advanced software.

Stojek, Zbigniew

183

Radiotracer Imaging of Sediment Columns  

NASA Astrophysics Data System (ADS)

Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, E? = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) ? Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (<1 day). This allows multiple measurements to be made on the same column and thus the sediment biology to be monitored non-invasively over time (i.e. after an augmentation has been introduced) and minimizes long-lived radioactive waste. Different parameters can be measured, depending on the tracer type and delivery. A constant infusion of a conservative tracer, such as the positron emitter Br-76 (T1/2= 16.2 hr), measures the exclusion fraction (as a function of position in the column), while a bolus maps the flow velocity as a function of position. A tracer that interacts chemically with the contents of the column (e.g., [99m-Tc(VII)O4]- reduced to 99m-TcO2 by Fe(II) ) yields a map of the chemical environment (e.g., the distribution of Fe(II)). Image of Tc-99m distribution in a column containing Rifle sediment at four times.

Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

2010-12-01

184

Effects of solvent-extraction contactor selection on flowsheet and facility design  

SciTech Connect

The notion is developed that the selection of a solvent extraction contactor is part of a more general development of principles and philosophy guiding the overall plant design. Specifically, the requirements and constraints placed on the plant by the solvent extraction system must be consistent with those imposed by the other operations, which generally are more expensive and more complicated. Were a conservative philosophy employed throughout the plant, the choice of pulsed columns seem correct. Were the plant intended to employ modern techniques and state-of-the-art technology, particularly in remote maintenance and process control, the selection of centrifugal contactors seems appropriate. The process improvements attainable from employing more stages in a more tightly controlled solvent extraction system seem marginal at present when applied to conventional flowsheets, although the cost-benefit may be attractive in a modern plant. The potential for improvement through major flowsheet modification can not presently be assessed quantitatively.

Whatley, M.E.

1982-01-01

185

Multispecies transport of metal–EDTA complexes and chromate through undisturbed columns of weathered fractured saprolite  

Microsoft Academic Search

Laboratory-scale tracer experiments were conducted to investigate the geochemical and hydrological processes that govern the fate and transport of organically chelated radionuclides and toxic metals in undisturbed saturated columns of weathered, fractured shale saprolite. Three long-term, reactive contaminant injections were pulsed onto three separate soil columns, with the following influent mixtures: (1) 109CdEDTA2?, (2) 109CdEDTA2? and 57,58Co(II)EDTA2?, and (3) 109CdEDTA2?,

M. A Mayes; P. M Jardine; I. L Larsen; S. C Brooks; S. E Fendorf

2000-01-01

186

Wobbling of a liquid column between unequal discs  

NASA Astrophysics Data System (ADS)

One of the most puzzling results of an experiment on the stability of long liquid columns under microgravity, performed aboard Spacelab-D2 in 1993 and named STACO, aiming at the analysis of deformations of nearly cylindrical liquid columns under several mechanical disturbances, is revisited here. It corresponds to the unexplained breakage of an 85 mm long liquid bridge of low viscosity silicone oil, established between unequal discs of 30 and 28 mm, intended to counterbalance the expected deformation by residual acceleration found in previous flights, and left idle because the vibrations and oscillations to be applied afterwards were not started, for fear of premature breakage. A detailed image analysis is performed to extract the maximum amount of data, to be able to check against available theories for axisymmetric and non-axisymmetric deformations of a liquid column.

Martínez, I.; Meseguer, J.; Perales, J. M.

187

LRC Chromatography Columns for Laboratory Applications  

E-print Network

volumes up to 900 mL and bed heights up to 750 mm. Column tubes are made of borosilicate glass of Description Construction Column Tube [1] Borosilicate glass Pistons: 1 adjustable [2] and 1 fixed [3] EachLRC Chromatography Columns for Laboratory Applications Empty glass columns accommodate sorbent

Lebendiker, Mario

188

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

189

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)

1994-01-01

190

WASTEWATER TREATMENT OVER SAND COLUMNS  

E-print Network

93/0096 WASTEWATER TREATMENT OVER SAND COLUMNS TREATMENT YIELDS, LOCALISATION OF THE BIOMASS Domestic wastewater treatment by infiltration-percolation is a process that becomming common in France, a greater depth for desinfection purposes. KEYWORDS Wastewater treatment, Infiltration-percolation. Sand

Paris-Sud XI, Université de

191

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

192

Monolithic molecularly imprinted polymeric capillary columns for isolation of aflatoxins.  

PubMed

Monolithic molecularly imprinted polymers extraction columns have been prepared in fused-silica capillaries by UV or thermal polymerization in a two-step process. First, a poly-(trimethylolpropane trimethacrylate) (polyTRIM) core monolith was synthesized either by UV or thermal polymerization. Then it was grafted with the mixture of methacrylic acid (MAA) as a functional monomer, ethylene dimethacrylate (EDMA) as a cross-linking agent, 5,7-dimethoxycoumarin (DMC) as an aflatoxin-mimicking template, toluene as a porogen solvent and 2,2-azobis-(2-methylpropionitrile) (AIBN) as an initiator of the polymerization reaction. Different thermal condition of the photografting and different concentrations of the grafting mixture were tested during polymerization. The extraction capillary columns were evaluated in the terms of their hydrodynamic and chromatographic properties. Retention coefficients for aflatoxin B1 and DMC were used for assessment of the selectivity and imprinting factor. The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs. From the MIP columns characterized by the highest permeability the column of the highest imprinting factor was applied for isolation of aflatoxins B1, B2, G1 and G2 from the model aqueous sample followed by on-line chromatographic separation. The process was performed using a micro-MISPE-microLC-LIF system of a novel design, which allowed for detection of the eluates from the sample preparation part as well as from the chromatographic separation. PMID:25218633

Szumski, Micha?; Grzywi?ski, Damian; Prus, Wojciech; Buszewski, Bogus?aw

2014-10-17

193

Rapid Actinide Column Extraction Methods for Bioassay Samples  

Microsoft Academic Search

A new, rapid separation method to assay actinides in urine samples has been developed at the Westinghouse Savannah River Site (SRS). The new method separates plutonium, neptunium, uranium, americium and strontium-90 with high chemical recovery and excellent thorium removal. The method uses calcium phosphate precipitation and stacked TEVA Resin(R) and TRU Resin(R) cartridges to separate and purify the actinides. Plutonium

2003-01-01

194

Rapid column extraction method for actinides in soil  

Microsoft Academic Search

Summary  The determination of actinides in environmental soil and sediment samples is very important for environmental monitoring as\\u000a well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides\\u000a total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA ResinÒ, TRU ResinÒ and DGA-ResinÒ

Sherrod L. Maxwell; Brian K. Culligan

2006-01-01

195

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

196

Feature extraction Feature extraction  

E-print Network

(hyperspectral sensors) Meteosat thermal IR channel hyperspectral "image cube" #12;Raw intensities · ProsFeature extraction #12;Feature extraction · Image interpretation: extract information from images · but the desired information may not be explicit in the raw observed pixel intensities · Transform image to make

Giger, Christine

197

Feature extraction Feature extraction  

E-print Network

(hyperspectral sensors) Meteosat thermal IR channel hyperspectral "image cube" #12;Raw intensities ! � ProsFeature extraction #12;Feature extraction ! � Image interpretation: extract information from images � but the desired information may not be explicit in the raw observed pixel intensities � Transform image to make

Giger, Christine

198

Rapid reversed-phase liquid chromatography separation of cyclolinopeptides with monolithic and microparticulate columns.  

PubMed

Three monolithic C(18)-bonded silica gel columns i.e. Chromolith SpeedROD (CSR), Chromolith Performance (CP), and Chromolith High Resolution (CHR), MerckKGaA Darmstadt, Germany and two particle-based columns i.e. ZORBAX Eclipse XDB-C(18) (ZEX), Agilent and POROS R1/20 (POR), Applied Biosystems were compared for their performance in separating a mixture of flaxseed cyclolinopeptides (CLs). Gradient mobile phases of acetonitrile and water were optimized for each column. The performance of CHR column in profiling CL standards, measured as the resolution of individual CL, selectivity, and peak asymmetry exceeded the performance of traditional particle-packed columns and the other monolithic columns. The profiling of CLs in aqueous methanolic flaxseed extract was optimized for high-throughput analysis. A total analysis time of 1.5 min at a flow rate of 3.0mLmin(-1) was achieved on a CSR column. Injection of over 2000 methanol extracts of flaxseed on a CSR column had no impact on backpressure or resolution of a standard CL mixture. PMID:22898105

Olivia, Clara M; Burnett, Peta-Gaye G; Okinyo-Owiti, Denis P; Shen, Jianheng; Reaney, Martin J T

2012-09-01

199

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,

200

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 ...

201

29 CFR 1926.755 - Column anchorage.  

...anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base plate weld and the column foundation, shall be designed to resist a minimum eccentric gravity load of 300 pounds (136.2 kg)...

2014-07-01

202

LRCLaboratoryColumns New York -USA  

E-print Network

to a standard system. The column body is made of a borosilicate glass tube. The columns are equipped with one torsional load on the packed bed and assures true linear compression. - True frits pressed into the plunger at the column inlet. 2. Inlet frit partially clogged. 3. Outlet frit partially clogged. 4. Separation efficiency

Lebendiker, Mario

203

Seismic reliability assessment of classical columns subjected to near-fault ground motions  

E-print Network

A methodology for the performance-based seismic risk assessment of classical columns is presented. Despite their apparent instability, classical columns are, in general, earthquake resistant, as proven from the fact that many classical monuments have survived many strong earthquakes over the centuries. Nevertheless, the quantitative assessment of their reliability and the understanding of their dynamic behavior are not easy, because of the fundamental nonlinear character and the sensitivity of their response. In this paper, a seismic risk assessment is performed for a multidrum column using Monte Carlo simulation with synthetic ground motions. The ground motions adopted contain a high- and low-frequency component, combining the stochastic method, and a simple analytical pulse model to simulate the directivity pulse contained in near source ground motions. The deterministic model for the numerical analysis of the system is three-dimensional and is based on the Discrete Element Method. Fragility curves are prod...

Psycharis, Ioannis; Stefanou, Ioannis

2013-01-01

204

Extraction chromatography: Progress and opportunities  

SciTech Connect

Extraction chromatography provides a simple and effective method for the analytical and preparative-scale separation of a variety of metal ions. Recent advances in extractant design, particularly the development of extractants capable of metal ion recognition or of strong complex formation in highly acidic media, have significantly improved the utility of the technique. Advances in support design, most notably the introduction of functionalized supports to enhance metal ion retention, promise to yield further improvements. Column instability remains a significant obstacle, however, to the process-scale application of extraction chromatography. 79 refs.

Dietz, M.L.; Horwitz, E.P.; Bond, A.H. [Argonne National Lab., IL (United States). Chemistry Div.

1997-10-01

205

Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments NAC/SETAC 2012  

EPA Science Inventory

Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

206

Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments (SETAC Europe 22nd Annual Meeting)  

EPA Science Inventory

Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

207

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

208

A technique using a stellar spectrographic plate to measure terrestrial ozone column depth  

SciTech Connect

This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.

Wong, A.Y.

1995-08-01

209

Water Column Correction for Coral Reef Studies by Remote Sensing  

PubMed Central

Human activity and natural climate trends constitute a major threat to coral reefs worldwide. Models predict a significant reduction in reef spatial extension together with a decline in biodiversity in the relatively near future. In this context, monitoring programs to detect changes in reef ecosystems are essential. In recent years, coral reef mapping using remote sensing data has benefited from instruments with better resolution and computational advances in storage and processing capabilities. However, the water column represents an additional complexity when extracting information from submerged substrates by remote sensing that demands a correction of its effect. In this article, the basic concepts of bottom substrate remote sensing and water column interference are presented. A compendium of methodologies developed to reduce water column effects in coral ecosystems studied by remote sensing that include their salient features, advantages and drawbacks is provided. Finally, algorithms to retrieve the bottom reflectance are applied to simulated data and actual remote sensing imagery and their performance is compared. The available methods are not able to completely eliminate the water column effect, but they can minimize its influence. Choosing the best method depends on the marine environment, available input data and desired outcome or scientific application. PMID:25215941

Zoffoli, Maria Laura; Frouin, Robert; Kampel, Milton

2014-01-01

210

Water column correction for coral reef studies by remote sensing.  

PubMed

Human activity and natural climate trends constitute a major threat to coral reefs worldwide. Models predict a significant reduction in reef spatial extension together with a decline in biodiversity in the relatively near future. In this context, monitoring programs to detect changes in reef ecosystems are essential. In recent years, coral reef mapping using remote sensing data has benefited from instruments with better resolution and computational advances in storage and processing capabilities. However, the water column represents an additional complexity when extracting information from submerged substrates by remote sensing that demands a correction of its effect. In this article, the basic concepts of bottom substrate remote sensing and water column interference are presented. A compendium of methodologies developed to reduce water column effects in coral ecosystems studied by remote sensing that include their salient features, advantages and drawbacks is provided. Finally, algorithms to retrieve the bottom reflectance are applied to simulated data and actual remote sensing imagery and their performance is compared. The available methods are not able to completely eliminate the water column effect, but they can minimize its influence. Choosing the best method depends on the marine environment, available input data and desired outcome or scientific application. PMID:25215941

Zoffoli, Maria Laura; Frouin, Robert; Kampel, Milton

2014-01-01

211

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.

212

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

213

Pulsed Operation of an Ion Accelerator  

NASA Technical Reports Server (NTRS)

Electronic circuitry has been devised to enable operation of an ion accelerator in either a continuous mode or a highpeak power, low-average-power pulsed mode. In the original intended application, the ion accelerator would be used as a spacecraft thruster and the pulse mode would serve to generate small increments of impulse for precise control of trajectories and attitude. The present electronic drive circuitry generates the extraction voltage in pulses. Pulse-width modulation can affect rapid, fine control of time-averaged impulse or ion flux down to a minimum level much lower than that achievable in continuous operation.

Wirz, Richard; Gamero-Castano, Manuel; Goebel, Dan

2009-01-01

214

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.

215

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...

216

Increasing sample throughput in pharmacological studies by using dual-column liquid chromatography with tandem mass spectrometry.  

PubMed

A robust novel technology of parallel chromatography combined with tandem mass spectrometry was successfully applied to a biological matrix extract for analyte detection. The presented study shows how only by using an additional isocratic pump, a second column and a 10-port valve the throughput is twice of that of a conventional single column system with the same sensitivity. Analytes and matrix were separated and eluting peaks of the first column were detected while the second column was equilibrated. The system was tested and used for the determination of several drugs, metabolites and endogenous compounds (i.e., propiverine, talinolol, scopolamine and leukotrienes). PMID:12831196

Oertel, R; Richter, K; Fauler, J; Kirch, W

2002-03-01

217

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

218

Cross-column prediction of gas-chromatographic retention of polybrominated diphenyl ethers.  

PubMed

In this paper, we predict the retention of polybrominated diphenyl ethers (PBDEs) in capillary gas-chromatography (GC) within a useful range of separation conditions. In a first stage of this study, quantitative structure-retention relationships (QSRRs) of PBDEs in six stationary phases with different polarity are established. The single-column QSRR models are generated using the retention data of 126 PBDE congeners by multilinear regression (MLR) coupled to genetic algorithm variable selection applied to a large set of theoretical molecular descriptors of different classes. A quite accurate fitting of experimental retentions is obtained for each of the six GC columns adopting five molecular descriptors. In a further step of this work six molecular descriptors were extracted within the set of molecular descriptors (17 variables) involved in the various single-column QSRRs. The selected molecular descriptors are combined with observed retentions of ten representative PBDEs, adopted as descriptors of the GC system. These quantities are considered as the independent variables of a multiple-column retention model able to simultaneously relate GC retention to PBDE molecular structure and kind of column. The quantitative structure/column-retention relationship is established using a multi-layer artificial neural network (ANN) as regression tool. To optimise the ANN model, a validation set is generated by selecting two out of the six calibration columns. Splitting of columns between training and validation sets, as well as selection of PBDE congeners to be used as column descriptors, is performed with the help of a principal component analysis on the retention data. Cross-column predictive performance of the final model is tested on a large external set consisting of retention data of 180 PBDEs collected in four separation conditions different from those considered in model calibration (different columns and/or temperature program). PMID:23726355

D'Archivio, Angelo Antonio; Giannitto, Andrea; Maggi, Maria Anna

2013-07-12

219

Pulse News  

NSDL National Science Digital Library

It can be quite fun to read the news, but about what the beauty of viewing a clutch of colorful news sites? Pulse is an "elegant news reading application" designed for the iPhone, Android, and other mobile devices. The application uses colorful panning story bars and populates them with content from sources (such as CNN, the BBC, and so on) selected by the user. Visitors can sign up for a free account, and they will also want to read over the FAQ section on the site.

2012-02-03

220

[Morphology and dynamics of the spinal column].  

PubMed

The function of the vertebral column--the supporting axial component of the body--can only be understood by detailed knowledge of its structure. For this reason the first part of the article gives a report of the latest findings on the ligaments and zygapophysial joints of the vertebral column. Particular emphasis has been laid on the functional cooperation of these ligaments and joints during movements of the segments of the column. The second part of the paper is concerned with the dynamic behaviour of the column in children and young people, and is described in terms of the anatomical information given before. The damping capacity of the spinal column and its rigidity depend on both the age of the subject and the position of the body. In the axial direction the damping effect of the column is relatively slight, but it becomes markedly increased during ventral flexion. PMID:6856812

Putz, R

1983-04-01

221

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

222

Accretion column eclipses in the X-ray pulsars GX 1+4 and RX J0812.4-3114  

E-print Network

Sharp dips observed in the pulse profiles of three X-ray pulsars (GX 1+4, RX J0812.4-3114 and A 0535+26) have previously been suggested to arise from partial eclipses of the emission region by the accretion column occurring once each rotation period. We present pulse-phase spectroscopy from Rossi X-ray Timing Explorer satellite observations of GX 1+4 and RX J0812.4-3114 which for the first time confirms this interpretation. The dip phase corresponds to the closest approach of the column axis to the line of sight, and the additional optical depth for photons escaping from the column in this direction gives rise to both the decrease in flux and increase in the fitted optical depth measured at this phase. Analysis of the arrival time of individual dips in GX~1+4 provides the first measurement of azimuthal wandering of a neutron star accretion column. The column longitude varies stochastically with standard deviation 2-6 degrees depending on the source luminosity. Measurements of the phase width of the dip both from mean pulse profiles and individual eclipses demonstrates that the dip width is proportional to the flux. The variation is consistent with that expected if the azimuthal extent of the accretion column depends only upon the Keplerian velocity at the inner disc radius, which varies as a consequence of the accretion rate Mdot.

D. K. Galloway; A. B. Giles; K. Wu; J. G. Greenhill

2000-10-25

223

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

224

Interstitial gas effect on vibrated granular columns.  

PubMed

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. PMID:25019768

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

2014-06-01

225

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

226

Solid Phase Extraction of Solanesol  

Microsoft Academic Search

The method of solid-phase extraction (SPE) for the concentration and clean-up of tobacco extract samples during solanesol\\u000a analysis was proposed in this work. A column (200 mm  4 mm i.d.) packed with 0.10 g silica gel (with particle size of 70 ?m,\\u000a porosity of 0.5 and surface area of 400 m2 g?1) was used as SPE cartridge. Several extraction parameters, such as sample loading flow (0.3–7 mL min?1), sample

De-Song Tang; Hui-Ling Liang; Lin Zhang; Huan-Lin Chen

2007-01-01

227

Application of a thermally coupled distillation column with separated main columns to gas concentration process  

Microsoft Academic Search

A modified fully thermally coupled distillation column (FTCDC) for operability improvement is utilized in a gas concentration\\u000a process. The column consists of a prefractionator and two separated main columns having high distillation efficiency and flexible\\u000a control structure. The operability of the proposed column is evaluated by examining the open-loop dynamic responses of step\\u000a input variations with the HYSYS simulation. The

Moon Yong Lee; Su Yeung Jeong; Young Han Kim

2008-01-01

228

Modelling failures in existing reinforced concrete columns  

Microsoft Academic Search

Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete col- umns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure dur- ing earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects

Kenneth J. Elwood

2004-01-01

229

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

230

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.

231

Chart 1 (350 characters) (1) c 2008729 : column 1 = simplified character, column 2 = traditional character  

E-print Network

2008729 #12;2 #12;Chart 1 (350 characters) (1) c 2008729 : column 1 = simplified character will hopefully be resolved in the future) 3 #12;4 #12;Chart 1 (350 characters) (2) 5 #12;6 #12;Chart 1 (350 characters) (3) c 2008729 : column 1 = simplified character, column 2

Roegel, Denis

232

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

233

First experimental implementation of pulse shaping for neutron diffraction on pulsed sources  

NASA Astrophysics Data System (ADS)

One of the central issues in the design and the use of pulsed neutron sources is the control of pulse length in elastic scattering experiments, most significantly diffraction on crystalline matter. On the existing short pulse spallation sources the strongly wavelength dependent source pulse length that determines the resolution is permanently fixed on each beam line by the type of the moderator it faces. We have experimentally implemented for the first time the wavelength frame multiplication (WFM) multiplexing chopper method, an earlier proposed variant of the by now fully tested repetition rate multiplication technique for inelastic scattering spectroscopy on pulsed neutron sources. We have operated the time-of-flight diffractometer at the continuous reactor source at BNC in an unconventional multiplexing mode that emulates a pulsed source. As a full proof of principle of the WFM method we have experimentally demonstrated the extraction from each source pulse a series of polychromatic, chopper shaped neutron pulses, which can continuously cover any wavelength band. The achieved 25 ?s FWHM pulse length is shorter than that can be obtained at all at short pulse spallation sources for cold neutrons. The method allows us to build efficient, high and variable resolution diffractometers at long pulse spallation sources.

Russina, M.; Káli, Gy.; Sánta, Zs.; Mezei, F.

2011-10-01

234

Multistatic adaptive pulse compression  

E-print Network

A new technique denoted as multistatic adaptive pulse compression (MAPC) is introduced which exploits recent work on adaptive pulse compression (APC) in order to jointly separate and pulse compress the concurrently received ...

Blunt, Shannon David; Gerlach, K.

2006-07-01

235

Fault tolerant pulse synchronization  

E-print Network

Pulse synchronization is the evolution of spontaneous firing action across a network of sensor nodes. In the pulse synchronization model all nodes across a network produce a pulse, or "fire", at regular intervals even without access to a shared...

Deconda, Keerthi

2009-05-15

236

Cross-column prediction of gas-chromatographic retention of polychlorinated biphenyls by artificial neural networks.  

PubMed

In this paper, we build a multiple-column retention model able to predict the behaviour of polychlorinated biphenyls (PCBs) in capillary gas-chromatography (GC) within a wide range of separation conditions. To this end, GC retention is related to both chemical structure of PCBs, encoded by selected theoretical molecular descriptors, and the kind of stationary phase, represented by the relative retention time (RRT) of a suitable small number of analytes. The model was generated using the retention data of 70 PCBs extracted from the pool of the 209 possible congeners collected on 17 different capillary columns featured by non-polar or moderately polar stationary phases, reported in the literature. Multilinear regression combined with genetic algorithm variable selection was preliminarily applied to generate a four-dimensional quantitative structure-retention relationship (QSRR) for each of the 17 columns, based on theoretical molecular descriptors extracted from the large set provided by the software Dragon. 33 molecular descriptors obtained by merging the non-common descriptors of various single-column QSRRs, combined with RRTs values of the less and the most retained PCB, were considered as the starting independent variables of the multiple-column retention model. A multi-layer artificial neural network (ANN), optimised on a validation set extracted from the calibration data, was applied to generate the multi-column retention model. The influence of starting inputs on the network output was evaluated by a sensitivity analysis and model complexity was reduced through a step-wise elimination of redundant molecular descriptors, while RRTs of further PCBs were included to improve description of the stationary phase. Nine molecular descriptors and RRTs of eight selected PCBs are considered as the independent variables of the final ANN-based model, whose predictive performance was tested on the 139 PCBs excluded from calibration and on six external columns and/or temperature programs. PMID:22000780

D'Archivio, Angelo Antonio; Incani, Angela; Ruggieri, Fabrizio

2011-12-01

237

Ion mobility based on column leaching of South African gold tailings dam with chemometric evaluation.  

PubMed

New column leaching experiments were designed and used as an alternative rapid screening approach to element mobility assessment. In these experiments, field-moist material was treated with an extracting solution to assess the effects of acidification on element mobility in mine tailings. The main advantage of this version of column leaching experiments with partitioned segments is that they give quick information on current element mobility in conditions closely simulating field conditions to compare with common unrepresentative air-dried, sieved samples used for column leaching experiments. Layers from the tailings dump material were sampled and packed into columns. The design of columns allows extracting leachates from each layer. The extracting solutions used were natural (pH 6.8) and acidified (pH 4.2) rainwater. Metals and anions were determined in the leachates. The concentrations of metals (Ca, Mg, Fe, Mn, Al, Cr, Ni, Co, Zn, and Cu) in sample leachates were determined using ICP OES. The most important anions (NO3-, Cl-, and SO4(2)-) were determined using the closed system izotacophoresis ITP analyser. The chemical analytical data from tailings leaching and physico-chemical data from field measurements (including pH, conductivity, redox potential, temperature) were used for chemometric evaluation of element mobility. Principal factor analysis (PFA) was used to evaluate ions mobility from different layers of tailings dump arising from varied pH and redox conditions. It was found that the results from the partitioned column leaching illustrate much better complex processes of metals mobility from tailings dump than the total column. The chemometric data analysis (PFA) proofed the differences in the various layers leachability that are arising from physico-chemical processes due to chemical composition of tailings dump deposit. PMID:15109878

Cukrowska, Ewa M; Govender, Koovila; Viljoen, Morris

2004-07-01

238

Column Studies on Reactive Mixing  

NASA Astrophysics Data System (ADS)

Reactive mixing of solutes in porous media has gained increasing interest since the beginning of the last decade. A better understanding of mixing in reactive transport is necessary to predict effectively groundwater remediation processes such as bioremediation and natural attenuation, as they may be controlled by mixing of the reacting compounds. It has been shown that classical macrodispersion concepts are not applicable to predict the actual mixing of compounds in heterogeneous media. Cirpka and Kitanidis (2000) suggested to quantify solute dilution by the second central moments of conservative breakthrough curves obtained at single points. From this quantity, it should be possible to predict reaction rates of non-sorbing reactants. The approach requires point measurements of a conservative tracer and reaction products. In the present study, we conduct experiments on mixing-controlled reactive transport in a one-dimensional water-saturated sand column. We use Fluorescein as tracer. Fluorescence intensity is measured directly within the sand filling by fiber-optic probes with a measurement volume of a few microliter. In the reactive tracer tests, an acidic solution containing the tracer is replaced by an alkaline solution without tracer. As fluorescence of Fluorescein is suppressed at low pH, fluorescence occurs only in the zone where the two solutions mix. To prevent sorption of Fluorescein at low pH, we add a non-ionic surfactant to both solutions. Conservative tracer experiments yield the mixing ratio of the two solutions at each point and time. With the mixing ratio, a titration curve of the two solutions and the relative fluorescence intensity as a function of pH, we can predict the reactive breakthrough curves for each probe. The zeroth moment of the predicted and measured reactive breakthrough curves differ by about 10%. The experimental method is also used in experiments in a large-scale sandbox with heterogeneous filling.

Jose, S. C.; Cirpka, O. A.

2003-04-01

239

Pretreatment method for immunoassay of polychlorinated biphenyls in transformer oil using multilayer capillary column and microfluidic liquid-liquid partitioning.  

PubMed

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that are present in the insulating oil inside a large number of transformers. To aid in eliminating PCB-contaminated transformers, PCBs in oil need to be measured using a rapid and cost-effective analytical method. We previously reported a pretreatment method for the immunoassay of PCBs in oil using a large-scale multilayer column and a microchip with multiple microrecesses, which permitted concentrated solvent extraction. In this paper, we report on a more rapid and facile pretreatment method, without an evaporation process, by improving the column and the microchip. In a miniaturized column, the decomposition and separation of oil were completed in 2 min. PCBs can be eluted from the capillary column at concentrations seven-times higher than those from the previous column. The total volume of the microrecesses was increased by improving the microrecess structure, the enabling extraction of four-times the amount of PCBs achieved with the previous system. By interfacing the capillary column with the improved microchip, PCBs in the eluate from the column were extracted into dimethyl sulfoxide in microrecesses with high enrichment and without the need for evaporation. Pretreatment was completed within 20 min. The pretreated oil was analyzed using a flow-based kinetic exclusion immunoassay. The limit of detection of PCBs in oil was 0.15 mg kg(-1), which satisfies the criterion set in Japan of 0.5 mg kg(-1). PMID:23574664

Aota, Arata; Date, Yasumoto; Terakado, Shingo; Ohmura, Naoya

2013-01-01

240

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

241

Numerical Simulation on Flow in Column Chromatography  

NASA Astrophysics Data System (ADS)

Monolithic columns have attracted much attention as a novel platform for high throughput analysis, but there is little information about the fluid profile in the flow channels. In this paper, we presented our approach for the fluid simulation in column chromatography by the lattice Boltzmann method (LBM). To simulate the monolithic column system, the calculation domain was modeled by the 3D channel flow through sphere obstacles. Several types of porous structure were used, with uniform and nonuniform pores. Based on the simulations results, we discussed fluid flow and pressure variation for the optimization of the suitable structure for HPLC system.

Yamamoto, Kazuhiro; Komiyama, Ryo; Umemura, Tomonari

2013-12-01

242

Pressure drop effects in packed capillary column supercritical fluid chromatography  

Microsoft Academic Search

The subject of column pressure drop has generated much controversy when using packed columns in supercritical fluid chromatography (SFC), since packed columns usually exhibit a ssignificant pressure drop along the column. In this paper, the effect of pressure drop on the chromatographic behavior of capillary columns packed with small spherical silica particles in SFC was studied using neat carbon dioxide

Wenbao Li; Abdul Malik; Milton L. Lee

1997-01-01

243

A new fully thermally coupled distillation column with postfractionator  

Microsoft Academic Search

For the improvement of distillation column efficiency, a new system of a fully thermally coupled distillation column is proposed and its performance is examined with two industrial processes. The system has an extra column called postfractionator and attached to the main column of an original fully thermally coupled distillation column.The outcome of performance investigation indicates that a 29% energy saving

Young Han Kim

2006-01-01

244

Breaking Row and Column Symmetries in Matrix Models  

Microsoft Academic Search

We identify an important class of symmetries in constraint programming, arising from matrices of decision variables where rows and columns can be swapped. Whilst lexicographically ordering the rows (columns) breaks all the row (column) symmetries, lexicographically or- dering both the rows and the columns fails to break all the compositions of the row and column symmetries. Nevertheless, our experimental re-

Pierre Flener; Alan M. Frisch; Brahim Hnich; Zeynep Kiziltan; Ian Miguel; Justin Pearson; Toby Walsh

2002-01-01

245

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

246

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

247

Efficiency of dioxin recovery from fly-ash samples during extraction and cleanup process  

Microsoft Academic Search

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. Steps of the extraction and the column cleanup procedures were evaluated by using radiolabeled (14)C-dioxins as tracers. Sample extracts and eluate fractions were analyzed by liquid scintillation counting and the results confirmed by gas

J. M. Finkel; R. H. James; K. W. Baughman; J. C. Pau; J. E. Knoll; M MIDGETT

1989-01-01

248

Surfactant recycling by solvent extraction in surfactant-aided remediation  

Microsoft Academic Search

As a part of the study on the surfactant-aided remediation of organic contaminants, solvent extraction was investigated to determine its efficiency for used surfactant recycling. The experiments used a glass column 70 cm height with an internal diameter of 3 cm. The convex orifice with four holes (4 mm outer diameter) was installed at the base of the column. Four

Dal-Heui Lee; Robert D. Cody; Dong-Ju Kim

2002-01-01

249

Digital Mammograms Classification Using a Wavelet Based Feature Extraction Method  

Microsoft Academic Search

This paper introduces a new method of feature extraction from wavelet coefficients for classification of digital mammograms. A matrix is constructed by putting wavelet coefficients of each image of a building set as a row vector. The method consists then on selecting by threshold, the columns which will maximize the Euclidian distances between the different class representatives. The selected columns

Ibrahima Faye; Brahim Belhaouari Samir; Mohamed M. M. Eltoukhy

2009-01-01

250

29 CFR 1926.755 - Column anchorage.  

Code of Federal Regulations, 2013 CFR

...1) Anchor rods (anchor bolts) shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record. (2) Prior to the erection of a column, the controlling contractor shall provide...

2013-07-01

251

29 CFR 1926.755 - Column anchorage.  

Code of Federal Regulations, 2011 CFR

...1) Anchor rods (anchor bolts) shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record. (2) Prior to the erection of a column, the controlling contractor shall provide...

2011-07-01

252

29 CFR 1926.755 - Column anchorage.  

Code of Federal Regulations, 2012 CFR

...1) Anchor rods (anchor bolts) shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record. (2) Prior to the erection of a column, the controlling contractor shall provide...

2012-07-01

253

AVIRIS Spectrometer Maps Total Water Vapor Column  

NASA Technical Reports Server (NTRS)

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) processes maps of vertical-column abundances of water vapor in atmosphere with good precision and spatial resolution. Maps provide information for meteorology, climatology, and agriculture.

Conel, James E.; Green, Robert O.; Carrere, Veronique; Margolis, Jack S.; Alley, Ronald E.; Vane, Gregg A.; Bruegge, Carol J.; Gary, Bruce L.

1992-01-01

254

Column Generation for Extended Formulations - Optimization Online  

E-print Network

Jul 8, 2011 ... Then, one can implement column generation for this extended formula- ... and rows of a full-blown extended formulation, one prices over the whole ...... nation property holds: when the reformulation stems from a network flow ...

2011-07-08

255

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

256

Analytical Modeling of a Bubble Column Dehumidifier  

E-print Network

Bubble column dehumidifiers are a compact, inexpensive alternative to conventional fin-tube dehumidifiers for humidification-dehumidification (HDH) desalination, a technology that has promising applications in small-scale ...

Tow, Emily W.

257

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

258

Divided Wall Column Without the Wall  

E-print Network

the partitions. Consequently, operating range is very limited. An additional thermodynamic deficiency inherent in the PETLYUK system lies within the vapor mixing and liquid mixing zones as further explained below. Let us focus on the vapor... Balanced Fully Thermally Coupled system (HBFTC system), is a column equipped with one reboiler 100 and one condenser 200. Further, the column is divided into four operating zones, in ascending elevation as follows: ?? A stripping zone, zone B, 1...

Tung, P.

2004-01-01

259

Heat Exchanger Technologies for Distillation Columns  

E-print Network

Heat Exchanger Technologies for Distillation Columns G.T.Polley Pinchtechnology.com In this paper we look at the challenges that improvements in energy efficiency of distillation systems presents the heat exchanger designer. We examine... condensate sub-cooling. So, if this condensate subsequently requires re-heating both energy and capital have been wasted. If the condensate forms a feed to another distillation column it results in increased energy consumption if that separation...

Polley, G. T.

260

Packed capillary columns for liquid chromatography  

Microsoft Academic Search

Summary  Fused silica capillaries, ? 130 ? 0.32mm have been packed with small reversed phase spherical silica particles, 3 or 2?m,\\u000a in order to achieve LC-systems giving high plate numbers at relatively low pressure drop in short analysis times. At optimal\\u000a conditions, columns packed with 3?m particles showed reduced plate heights, h, around 2.5, and the column flow resistance,\\u000a ?, was

S. Hoffmann; L. Blomberg

1987-01-01

261

Pulsed Zeeman spectroscopy  

E-print Network

Pulse from Stobotac 4. Upper Trace: Pulse from Pulse Generator Lower Trace: Pulse from Delay Line 5. Upper Trace: Voltage across 0. 787 Ohm Resistor Lower Trace: Output Voltage of Pulse Transformer Page 10 6. Pulse Coil Assembly 12 7. Temperature... an impedance of 0. 5 ohm to obtain highest power dis. , ipation. The pulse transformer as supplied vas modified by the addition of a 0. 787 ohm low inductance resistor made of flat nichrome ribbon. This resistor vas placed in series with the primary...

Cullen, Raymond Paul

2012-06-07

262

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. PMID:22043448

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

2010-01-01

263

Affinity-based screening of combinatorial libraries using automated, serial-column chromatography  

SciTech Connect

The authors have developed an automated serial chromatographic technique for screening a library of compounds based upon their relative affinity for a target molecule. A {open_quotes}target{close_quotes} column containing the immobilized target molecule is set in tandem with a reversed-phase column. A combinatorial peptide library is injected onto the target column. The target-bound peptides are eluted from the first column and transferred automatically to the reversed-phase column. The target-specific peptide peaks from the reversed-phase column are identified and sequenced. Using a monoclonal antibody (3E-7) against {beta}-endorphin as a target, we selected a single peptide with sequence YGGFL from approximately 5800 peptides present in a combinatorial library. We demonstrated the applicability of the technology towards selection of peptides with predetermined affinity for bacterial lipopolysaccharide (LPS, endotoxin). We expect that this technology will have broad applications for high throughput screening of chemical libraries or natural product extracts. 21 refs., 4 figs.

Evans, D.M.; Williams, K.P.; McGuinness, B. [PerSeptive Biosystems, Framingham, MA (United States)] [and others] [PerSeptive Biosystems, Framingham, MA (United States); and others

1996-04-01

264

Extraction of sucrose from molasses  

SciTech Connect

Sucrose is extracted from molasses by passing an aqueous molasses solution over an adsorbent, e.g., calcined Al/sub 2/O/sub 3/-supported pyrolyzed C/sub 6/H/sub 6/. Thus, 10 mL molasses (approximately 46% solids) was run through a column containing 70 cubic centimetres above adsorbent with sucrose retention volume 21.4 and selectivity for sucrose - betaine 23.8.

Landis, A.M.

1982-01-26

265

Rapid, economical qualitative method for separation of aflatoxins B-1, B-2 & G-1, G-2 by dry column chromatography.  

PubMed

A good correlation of four components of aflatoxins was accomplished by using the dry column chromatography method. The decolorization process of interfering substances, by 0.01 N KOH and defatting the extract with petroleum ether yields a clean residue for DCC separation. It is clear that the dry column chromatography is a very simple and time-saving procedure for separation of aflatoxins. DCC columns are more economical than precoated 'thick layer' preparative plates and, in DCC, no large developing tanks need to be used. Hazards associated with the use of large volumes of flammable solvents are greatly reduced. PMID:6323985

Megalla, S E

1983-12-01

266

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

267

Third Sound Pulse Collisions  

NASA Astrophysics Data System (ADS)

We report measurements of third sound pulses in head-on collisions (K. S. Ketola, S. Wang, and R. B. Hallock, Physica B 194--196), 651 (1994). as a function of superfluid ^4He film thickness, pulse amplitude and pulse width for temperatures near 1.5 K. The substrate is a borosilicate glass slide with two Ag thermal drivers and an Al transition edge bolometer located halfway between the drivers. By generating one heating pulse from each driver separated by a selectable time delay, we can measure the profile of a collision with the bolometer, or we can cause the collision to occur between the bolometer and one of the drivers and observe the scattered third sound pulse. We explore collisions for a variety of conditions and show how the pulse interactions depend on the drive amplitudes. Measurements of single cooling pulses, cooling pulse collisions and heating pulses in an applied steady film flow will also be presented.

Hallock, R. B.; Lilly, M. P.

1996-03-01

268

Pulse Rate Estimation Using Hydraulic Bed Sensor B.Y. Su, K.C. Ho, M. Skubic, and L. Rosales  

E-print Network

method utilizes the Hilbert transform to effectively capture the j-peak, which allows the pulse rate component, the Hilbert transform [9][10] is applied to extract the pulse envelopes from which the pulse rate in section II. In section III, the approach of using the Hilbert transform for pulse rate estimation

He, Zhihai "Henry"

269

Miniature electron beam column with a silicon micro field emitter  

SciTech Connect

Silicon micro field emitters (Si-MFEs) are expected to be promising as electron sources for their high brightness and ease in making arrayed microcolumns due to small physical size. We have developed a Si-MFE electron gun assembly that produces an electron beam of 1 keV. All components including the Si acceleration electrode are mounted on an integrated circuit (IC) package stem (TO-8) by anodic and eutectic bonding. A high brightness (75 {mu}A/sr) and a long lifetime ({gt}1000 h) have been observed. To overcome the intrinsic emission instability of Si-MFEs, we developed a simple feedback circuit which controls an extraction voltage. The source position shift and the aberration coefficient change caused by stabilization were evaluated analytically and found to be negligible due to the scaling law as applied to micron size. We confirmed that the total emission fluctuation could be stabilized to less than 1{percent} by detecting the absorption current but also found that this detection should be done in the electron beam column to stabilize the probe current due to the instability of the emission angle. Using the Si-MFE electron gun along with a miniature electron beam column 5 cm in length, we evaluated the electron optical properties and succeeded in demonstrating a scanning electron microscope operation with a resolution less than 0.5 {mu}m. {copyright} {ital 1997 American Vacuum Society.}

Honjo, I.; Endo, Y.; Goto, S. [Fujitsu Laboratories, Ltd., 10-1 Morinosato Wakamiya, Atsugi 243-01 (Japan)] [Fujitsu Laboratories, Ltd., 10-1 Morinosato Wakamiya, Atsugi 243-01 (Japan)

1997-11-01

270

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

271

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

272

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

273

CUB DI (Deionization) column control system  

SciTech Connect

For the old MR (Main Ring), deionization was done with two columns in CUB, using an ion exchange process. Typically 65 GPM of LCW flew through a column, and the resistivity was raised from 3 Mohm-cm to over 12 Mohm-cm. After a few weeks, columns lost their effectiveness and had to be regenerated in a process involving backwashing and adding hydrochloric acid and sodium hydroxide. For normal MR operations, LCW returned from the ring and passed through the two columns in parallel for deionization, although the system could have been operated satisfactorily with only one in use. A 3000 gallon reservoir (the Spheres) provided a reserve of LCW for allowing water leaks and expansions in the MR. During the MI (Main Injector) construction period, the third DI column was added to satisfy requirements for the MI. When the third column was added, the old regeneration controller was replaced with a new controller based on an Allen-Bradley PLC (i.e., SLC-5/04). The PLC is widely used and well documented, and therefore it may allow us to modify the regeneration programs in the future. In addition to the above regeneration controller, the old control panels (which were used to manipulate pumps and valves to supply LCW in Normal mode and to do Int. Recir. (Internal Recirculation) and Makeup) were replaced with a new control system based on Sixtrak Gateway and I/O modules. For simplicity, the new regeneration controller is called as the US Filter system, and the new control system is called as the Fermilab system in this writing.

K. C. Seino

1999-07-02

274

Self-organized, ordered array of coherent orthogonal column nanostructures in epitaxial La0.8Sr0.2MnO3 thin films  

Microsoft Academic Search

We report direct transmission electron microscopy evidence of self-organized, ordered array of coherent orthogonal column nanostructures in epitaxial La0.8Sr0.2MnO3 (LSMO) thin films grown on (001) LaAlO3 (LAO) using pulsed-laser ablation. The orthogonal column nanostructures have an orthorhombic structure and are epitaxially grown on a continuous cubic perovskite LSMO thin-film layer that is epitaxially grown on (001) LAO substrate. The orthogonal

J. C. Jiang; E. I. Meletis; K. I. Gnanasekar

2002-01-01

275

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

276

Mass transfer in a wetted wall column  

E-print Network

MASS TRANSPER IM A WETTED WALL COLDMM A Thesis Allison M. Platt June, 1950 MASS TRANSFER IN A WETTED WALL COLUMN A Thesis Allison M. Platt June~ 1950 Approved as to st@i and content recommended: Head of the Department of C cal Engineering... MASS TRANSFER IN A WETTED WALL COLUMN A Thesis Submitted to the Faculty of the Agricultural snd Mechanical College oi' Texas Partial FulfiUment of the Requirements for the Degree of Master of Science ~or Sub)ect: Chemical Engineering Allison M...

Platt, Allison M

2012-06-07

277

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

278

Constant potential pulse polarography  

USGS Publications Warehouse

The new technique of constant potential pulse polarography, In which all pulses are to be the same potential, is presented theoretically and evaluated experimentally. The response obtained is in the form of a faradaic current wave superimposed on a constant capacitative component. Results obtained with a computer-controlled system exhibit a capillary response current similar to that observed In normal pulse polarography. Calibration curves for Pb obtained using a modified commercial pulse polarographic instrument are in good accord with theoretical predictions.

Christie, J.H.; Jackson, L.L.; Osteryoung, R.A.

1976-01-01

279

Optically pulsed electron accelerator  

DOEpatents

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, J.S.; Sheffield, R.L.

1985-05-20

280

Divided-pulse lasers.  

PubMed

We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16 times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single-mode fiber. Potential extensions of this concept are discussed. PMID:24784100

Lamb, Erin S; Wright, Logan G; Wise, Frank W

2014-05-01

281

Divided-Pulse Lasers  

PubMed Central

We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16-times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single mode fiber. Potential extensions of this concept are discussed. PMID:24784100

Lamb, Erin S.; Wright, Logan G.; Wise, Frank W.

2014-01-01

282

Laser pulse synthesis system  

US Patent & Trademark Office Database

A laser pulse synthesis system is provided. A further aspect of the present system uses a phase-only modulator to measure ultrashort laser pulses. An additional aspect achieves interferences between split subpulses even though the subpulses have different frequencies. Yet another aspect of a laser system employs multi-comb phase shaping of a laser pulse. In another aspect, a laser system includes pulse characterization and arbitrary or variable waveform generation through spectral phase comb shaping.

2014-03-18

283

Alternate drop pulse polarography  

USGS Publications Warehouse

The new technique of alternate drop pulse polarography is presented. An experimental evaluation of alternate drop pulse polarography shows complete compensation of the capacitative background due to drop expansion. The capillary response phenomenon was studied in the absence of faradaic reaction and the capillary response current was found to depend on the pulse width to the -0.72 power. Increased signal-to-noise ratios were obtained using alternate drop pulse polarography at shorter drop times.

Christie, J.H.; Jackson, L.L.; Osteryoung, R.A.

1976-01-01

284

Multidimensional spectroscopy with a single broadband phase-shaped laser pulse Rachel Glenn and Shaul Mukamel  

E-print Network

are narrower than compared to a transform limited pulse.26 This technique27 can be used to extract the lineMultidimensional spectroscopy with a single broadband phase-shaped laser pulse Rachel Glenn-free molecular alignment control by phase-shaped femtosecond laser pulse J. Chem. Phys. 135, 224308 (2011); 10

Mukamel, Shaul

285

The Discrete Pulse Transform  

Microsoft Academic Search

We investigate a recent algorithm, here called a discrete pulse transform (DPT), for the multiresolution analysis of a sequence. A DPT represents a sequence as a sum of pulses, where a pulse is a sequence which is zero everywhere except for a certain number of consecutive elements which have a constant nonzero value. Unlike the discrete Fourier and wavelet transforms,

C. H. Rohwer; D. P. Laurie

2006-01-01

286

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

287

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

288

Research on Configurations of Thermally Integrated Distillation Column(TIDC)  

Microsoft Academic Search

\\u000a Taking a C3 distillation column as the base case, possible configurations for Thermally Integrated Distillation Columns (TIDC)\\u000a are proposed and compared to a conventional column and a column with a vapor recompression system (VRC). Thermal efficiency\\u000a of the TIDC appears to be strongly sensitive to column configuration and a highly efficient asymmetrical configuration with\\u000a stripping section stages thermally interconnected with

Lanyi Sun; Jun Li; Xuenuan Liu; Qingsong Li

2011-01-01

289

Determination of adenine and pyridine nucleotides in glucose-limited chemostat cultures of Penicillium simplicissimum by one-step ethanol extraction and ion-pairing liquid chromatography.  

PubMed

Under specific conditions Penicillium simplicissimum excretes large amounts of organic acids, mainly citrate. As the energetic status of the hyphae might play a role in that respect, we developed a method for the determination of adenine (adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate) and pyridine (nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide (NADH)) nucleotides in hyphae of P. simplicissimum. An optimum separation of the five compounds in less than 15 min was possible on a C-8 column, utilizing 50 mM aqueous triethylamine-buffer (pH 6.5) and acetonitrile as mobile phase; detection was performed at 254 nm. With the exception of NADH, which could not be determined accurately due to stability problems, the method was sensitive (LOD < or = 0.7 ng on-column), repeatable (sigma(rel) < or = 4.4%), accurate (recovery rates between 97.9 and 104.9%), and precise (intraday variation < or = 9.4%, interday variation < or = 6.2 %). For an optimum extraction of the nucleotides the chemostat samples were directly placed into hot (90 degrees C) 50% ethanol, and shaken for 10 min, followed by evaporation of the solvent and a solid phase extraction cleanup of the redissolved aqueous samples. With this method the nucleotide concentrations in hyphae from a glucose-limited chemostat culture and the respective energy charge were determined. Additionally, the effect of the time lag between sampling and extraction and the effect of a glucose pulse on nucleotide concentrations were determined. PMID:17054897

Ganzera, Markus; Vrabl, Pamela; Wörle, Elisabeth; Burgstaller, Wolfgang; Stuppner, Hermann

2006-12-01

290

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

291

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

292

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

293

ACM SIGACT news distributed computing column 13  

Microsoft Academic Search

The Distributed Computing Column covers the theory of systems that are composed of a number of interacting computing elements. These include problems of communication and networking, databases, distributed shared memory, multiprocessor architectures, operating systems, verification, Internet, and the Web.This issue describes the PODC 20th anniversary Special Issue published by Distributed Computing journal.

Sergio Rajsbaum

2003-01-01

294

Solutions diversification in a column generation algorithm  

E-print Network

and the one-dimensional cutting stock problem. Key words: column generation; diversification; stabilization; cutting stock problem, vehicle routing problem with time windows. 1 Introduction During the past few the Restricted Master Problem (RMP) description; in dual space, the oracle produces a cutting plane that refines

Létocart, Lucas

295

Visualization of viscous fingering in chromatographic columns  

Microsoft Academic Search

A 17 mm I.D. glass column, packed with YMC-15 (spherical C18 silica, 30 ?m particles) as the stationary phase and used with carbon tetrachloride as the mobile phase provided a suitable system for the visual observation of viscous fingering inside the packed bed, after the cylindrical lens effect had been canceled. Such a system appears nearly transparent due to the

B. Scott Broyles; R. Andrew Shalliker; Djamel E Cherrak; Georges Guiochon

1998-01-01

296

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

297

Inklings: Collected Columns on Leadership and Creativity.  

ERIC Educational Resources Information Center

This book brings together 35 of David P. Campbell's essays originally published as a regular column in a quarterly publication called "Issues and Observations." The articles deal with topics ranging from leadership issues such as risk-taking, executive motivation, decision making, and corporate taboos, to more general concerns such as father-son…

Campbell, David P.

298

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

299

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

300

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.

2003-06-15

301

Nanosecond length electron pulses from a laser-excited photocathode  

SciTech Connect

A photocathode made from polycrystalline lanthanum hexaboride (LaB{sub 6}) has produced nanosecond length electron pulses when excited by an excimer laser at 308nm. Peak currents in excess of 1A have been observed, with quantum yields of 4 {times} 10{sup {minus}5} being measured. A method for extracting the electrons from an emission-limited cathode, plasma extraction, has been demonstrated. This technique uses a low power continuous discharge to provide the electric field needed to extract the photoelectrons. This technique may be useful in producing high repetition rate short pulse ion sources. 10 refs., 4 figs.

Young, A.T.; D'Etat, B.; Stutzin, G.C.; Leung, K.N.; Kunkel, W.B.

1989-06-01

302

Fast method development of rooibos tea phenolics using a variable column length strategy.  

PubMed

The development of a method for the separation of standard compounds of the 15 main phenolics found in rooibos tea is presented. The separation of these compounds in a single HPLC analysis is particularly challenging due to the similarity of rooibos phenolics. As a result, multiple methods are often required to analyze all major phenolics in rooibos tea samples. The method development process is significantly enhanced in this study by using the recently introduced automated column coupler in combination with the variable column length strategy. This strategy consists of performing the initial scouting runs, wherein the best separation conditions are determined, on a short column and subsequently fine-tuning the separation on longer columns to benefit from their higher separation performance. It is demonstrated that the method development process can further be expedited by operating each column length at the maximum pressure, in this case 1000 bar. Although this holds in general, it is even more the case for the presently considered sample, since the selectivity of the sample is more pressure- than temperature-dependent. Applying the optimized method to unfermented and fermented aqueous rooibos tea extracts in combination with Q-TOF mass spectrometry, some 30 phenolic compounds are tentatively identified. PMID:21907344

Cabooter, Deirdre; Broeckhoven, Ken; Kalili, Kathithileni M; de Villiers, André; Desmet, Gert

2011-10-14

303

Bayesian Monte Carlo updating of Hudson River PCB model using water column PCB measurements  

SciTech Connect

The authors have developed prior probability distributions for model parameters and terms describing physico-chemical processes in sediment and water column models of PCB fate in a segment of the lower Hudson River, and performed importance analyses to identify the key uncertainties affecting the models` predictive power. In this work, the authors employ field measurements of the mean total water column PCB concentration from nearby river segments to refine the prior probability distributions for the important parameters and terms in the water column PCB model, using Bayesian Monte Carlo analysis. The principal objectives of the current work are (1) to implement Bayesian Monte Carlo analysis, to demonstrate the technique and evaluate its potential benefits, and (2) to improve the parameterization of the water column PCB model on the basis of site-specific PCB concentration data. The Bayesian updating procedure resulted in improved estimates of PCB mass loading and re-suspension velocity terms, but posteriors for three other key parameters -- settling velocity and particulate PCB fractions in the water column and surface sediments -- were unaffected by the information extracted from the new field data. In addition, the authors found that some of the high posterior probability parameter vectors, though mathematically plausible, were physically implausible, as a consequence of the unrealistic (but common) Monte Carlo assumption that the model`s parameters are independently distributed. The implications of this and other findings are discussed.

Zhang, S. [ETI, Seattle, WA (United States); Toll, J.; Cothern, K. [Foster Wheeler Environmental, Bellevue, WA (United States)

1995-12-31

304

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

305

Effect of the column length on the characteristics of the packed bed and the column efficiency in a dynamic axial compression column  

Microsoft Academic Search

The axial homogeneity of preparative-scale chromatography columns was studied by measuring the overall properties of similar columns differing only by their lengths. The properties investigated were the packing density, the external porosity, the permeability and the column efficiency. Two different materials were used, one made of large, irregular silica particles compressed under either a high or a low degree of

Joon-Ho Koh; Georges Guiochon

1998-01-01

306

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

307

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

308

Oxidation State and Extraction of Neptunium with TBP  

Microsoft Academic Search

The change of Np oxidation state in nitric acid and the effect of nitrous acid on the oxidation state were analyzed by spectrophotometry, solvent extraction, and electrochemical methods. The Np extraction with 30 vol.% TBP was enhanced by the adjustment of the Np oxidation state using a glassy carbon fiber column electrode system. The knowledge of electrolytic behavior of nitric

Kwang-Wook Kim; Kee-Chan Song; Eil-Hee Lee; In-Kyu Choi; Jae-Hyung Yoo

2000-01-01

309

Determination of free and total myo-inositol in infant formula and adult/pediatric nutritional formula by high- performance anion exchange chromatography with pulsed amperometric detection, including a novel total extraction using microwave-assisted acid hydrolysis and enzymatic treatment: first action 2012.12.  

PubMed

After an assessment of data generated from a single-laboratory validation study published in J. AOAC Int. 95, 1469-1478 (2012), a method for determining total myo-inositol in infant formula and adult/ pediatric nutritional formula by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), including extraction by using microwave-assisted acid hydrolysis and enzymatic treatment was presented for consideration by AOAC during the AOAC Annual Meeting held in Las Vegas, NV, from September 30 to October 3, 2012. The Expert Review Panel on Infant Formula and Adult Nutritionals concluded that the method met the criteria set by the standard method performance requirements (SMPRs) for the determination of free myo-inositol and approved the method as AOAC Official First Action. The method also determines total myo-inositol, but includes bound sources that the SMPRs exclude. The method involves using HPAEC-PAD for free myo-inositol and a total myo-inositol determination by two different techniques. The first technique uses the conventional acid hydrolysis with 6 h incubation in an autoclave. The second uses a microwave-assisted acid hydrolysis with enzymatic treatment that decreases the extraction time. PMID:24282949

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

2013-01-01

310

Biodegradation and regeneration of water-soluble carbon in a forest soil: leaching column study  

Microsoft Academic Search

We hypothesized that water-soluble C is a major substrate for microbial activity and studied the susceptibility of water-soluble C both to leaching and to microbial degradation. Soil columns, consisting of A-horizon top soil with and without tree seedlings, were leached every 2 weeks for 20 weeks. Water-soluble material was extracted from the soils before and after the 20-week study. Biodegradability

Rota Wagai; Phillip Sollins

2002-01-01

311

Thin-layer and liquid column chromatographic analyses of the lipids of adult Onchocerca gibsoni  

Microsoft Academic Search

Lipids were extracted from adultOnchocerca gibsoni with chloroform\\/methanol and the total lipid content was characterized. Glycolipids were isolated from other lipid classes by Florisil column chromatography and were then fractionated by DEAE-Sephadex ionexchange chromatography. HPTLC revealed the presence of 9 neutral glycolipid bands and of 15 acidic glycolipid bands that stained for sialic acid with resorcinol. Lipids that contained no

M. D. Maloney; L. H. Semprevivo

1991-01-01

312

Determination of roquefortine C in blue cheese using on-line column-switching liquid chromatography  

Microsoft Academic Search

A method is described for the determination of roquefortine C in (blue) cheese. After liquid–liquid extraction with a mixture of hydrochloric acid and methanol, and filtration, an aliquot is analysed using column-switching reversed-phase liquid chromatography. The recovery of roquefortine C in Fetta cheese is about 85%, the calibration curve is linear from 10 to 2500 ng g?1 (r2=0.998), and the

E Noroozian; F Lagerwerf; H Lingeman; U. A. TH Brinkman; M. A. T Kerkhoff

1998-01-01

313

Determination of Simvastatin in Human Plasma by Column?Switching HPLC with UV Detection  

Microsoft Academic Search

The purpose of this study was to develop and validate a sensitive and specific analytical method for determination of simvastatin in human plasma by the column?switching high performance liquid chromatography (HPLC) system with UV detection. Simvastatin was extracted in diethyl ether from plasma. The residue was dissolved in mobile phase I [acetonitrile–20 mM potassium phosphate buffer (45:55, v\\/v, pH 5.6)] and

Eunmi Ban

2005-01-01

314

Amino acid composition of soil peptides chromatographed by high performance liquid chromatography on C18 and C8 columns  

Microsoft Academic Search

Low molecular weight fractions (LMW; <5000 daltons) of organic matter were isolated from three soils by a mild extraction procedure and gel-permeation chromatography. The peptides present in the LMW soil extracts were separated on a Whatman Partisphere C18 and a Beckman Ultrapore C8 column by reverse-phase high performance liquid chromatography (HPLC). The peptide fractions were collected, acid hydrolyzed, and analyzed

R. A. Isnor; P. R. Warman

1990-01-01

315

Analysis of microwave leaky modes propagating through laser plasma filaments column waveguide  

SciTech Connect

A plasma column waveguide formed by a bundle of closely spaced plasma filaments induced by the propagation of ultrafast laser pulses in air and revived by a longer infrared laser pulse is shown to support microwave radiation. We consider values of both the plasma electron density and microwave frequency for which the refractive index of plasma is lower than the refractive index of air; therefore, a leaky plasma waveguide can be realized in extremely high frequency band. The guiding mechanism does not require high conductance of the plasma and can be easily excited by using commercial femtosecond laser sources. A theoretical study of leaky mode characteristics of isotropic and homogeneous plasma column waveguides is investigated with several values of plasma and waveguide structure parameters. The microwave transmission loss was found to be mainly caused by the microwave leakage through the air-plasma interface and is weakly dependent on the plasma absorption. In spite of losses of microwaves caused by leakage and plasma absorption, it is shown to be much lower than both that accompanying to surface waves attaching to single conducting plasma wire and the free space propagation over distances in the order of the filament length, which opens exciting perspectives for short distance point to point wireless transmission of pulsed-modulated microwaves.

Alshershby, Mostafa; Hao Zuoqiang; Lin Jingquan [School of Science, Changchun University of Science and Technology, Changchun 130022 (China)

2012-12-15

316

Transverse bacterial migration induced by chemotaxis in a packed column with structured physical heterogeneity  

PubMed Central

The significance of chemotaxis in directing bacterial migration towards contaminants in natural porous media was investigated under groundwater flow conditions. A laboratory-scale column, with a coarse-grained sand core surrounded by a fine-grained annulus, was used to simulate natural aquifers with strata of different hydraulic conductivities. A chemoattractant source was placed along the central axis of the column to model contaminants trapped in the heterogeneous subsurface. Chemotactic bacterial strains, Escherichia coli HCB1 and Pseudomonas putida F1, introduced into the column by a pulse injection, were found to alter their transport behaviors under the influence of the attractant chemical emanating from the central source. For E. coli HCB1, approximately 18% more of the total population relative to the control without attractant exited the column from the coarse sand layer due to the chemotactic effects of ?-methylaspartate under an average fluid velocity of 5.1 m/d. Although P. putida F1 demonstrated no observable changes in migration pathways with the model contaminant acetate under the same flow rate, when the flow rate was reduced to 1.9 m/d, approximately 6~10% of the population relative to the control migrated from the fine sand layer towards attractant into the coarse sand layer. Microbial transport properties were further quantified by a mathematical model to examine the significance of bacterial motility and chemotaxis under different hydrodynamic conditions, which suggested important considerations for strain selection and practical operation of bioremediation schemes. PMID:19731698

Wang, Meng; Ford, Roseanne M.

2009-01-01

317

Variation of the pulse profile of Hercules X-1  

NASA Technical Reports Server (NTRS)

The X-ray pulsar Her X-1 was observed in an on-state during its 35th cycle of activity in May, 1983 using the gas scintillation proportional counter (GSPC) array of the Tenma X-ray astronomy satellite. The outstanding features observed during the declining phase of the on-state included: a sharp decrease in the main X-ray pulse amplitude; and a steady increase in the column density of cool matter. On the basis of the spectral shape of the pulses, it is suggested that the main phase was attenuated due to electron scattering of the X-ray beam in a highly ionized medium located 3 x 10 to the 8th cm from the neutron star. Near the end of the on-state, the main pulse totally disappeared and a plain sinusoidal profile was observed. The observed pulse profiles are reproduced in graphic form.

Ohashi, T.; Inoue, H.; Kawai, N.; Koyama, K.; Matsuoka, M.; Mitani, K.; Tanaka, Y.; Nagase, F.; Nakagawa, M.; Kondo, Y.

1984-01-01

318

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

319

Effects of pulse frequency on the microstructure, composition and optical properties of pulsed dc reactively sputtered vanadium oxide thin films  

NASA Astrophysics Data System (ADS)

Vanadium oxide (VOx) thin films were prepared on unheated glass substrate by pulsed dc reactive magnetron sputtering using different pulse frequency. Field emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) measurements were made on the deposited VOx films to characterize the microstructure, composition and optical properties, respectively. It was found that under the same discharge power and argon-oxygen atmosphere, with the increase of pulse frequency, the vertical column-like structure in the films will gradually disappear and the ratio of high-valent VOx to low-valent VOx will obviously elevate. Optical parameters of the VOx films have been obtained by fitting the ellipsometric data (? and?) using the Tauc-Lorentz dispersion relation and a multilayer model (air/roughness layer/VOx/glass). The results demonstrated that pulse frequency plays a critical role in determining the transmittance, refractive index, extinction coefficient and optical band gap etc. The correlations between the microstructure, composition, optical properties and pulse frequency are also given by our experiment results. And the mechanisms for the evolution of the microstructure, composition and optical properties with pulse frequency have been discussed. Overall, due to the pulse frequency had a great effect not only on the growth characteristics but also on the optical properties of the VOx films, thus through variation of the pulse frequency during deposition which provide a convenient and efficient approach to control and optimize the performances of the VOx films.

Dong, Xiang; Wu, Zhiming; Jiang, Yadong; Xu, Xiangdong; Yu, He; Gu, Deen; Wang, Tao

2014-09-01

320

Column solid phase extraction and flame atomic absorption spectrometric determination of manganese(II) and iron(III) ions in water, food and biological samples using 3-(1-methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid on synthesized graphene oxide.  

PubMed

A modified, selective, highly sensitive and accurate procedure for the determination of trace amounts of manganese and iron ions is established in the presented work. 3-(1-Methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid (MPPC) and graphene oxide (GO) were used in a glass column as chelating reagent and as adsorbent respectively prior to their determination by flame atomic absorption spectrometry. The adsorption mechanism of titled metals complexes on GO was investigated by using computational chemistry approach based on PM6 semi-empirical potential energy surface (PES). The effect of some parameters including pH, flow rate and volume of sample and type, volume and concentration of eluent, as well as the adsorption capacity of matrix ions on the recovery of Mn(II) and Fe(III) was investigated. The limit of detection was 145 and 162 ng L(-1) for Mn(II) and Fe(III), respectively. Calibration was linear over the range of 0.31-355 ?g L(-1) for Mn(II) and 0.34-380 ?g L(-1) for Fe(III) ions. The method was successfully applied for the determination of understudied ions in water, food and biological samples. PMID:24411390

Pourjavid, Mohammad Reza; Sehat, Ali Akbari; Arabieh, Masoud; Yousefi, Seyed Reza; Hosseini, Majid Haji; Rezaee, Mohammad

2014-02-01

321

FUSED SILICA CAPILLARY COLUMN GC/MS QUALITY CONTROL PROTOCOL FOR THE DETERMINATION OF SEMIVOLATILE PRIORITY POLLUTANTS  

EPA Science Inventory

This quality control protocol is intended to serve as a guide to those laboratories employing fused silica capillary column (FSCC) gas chromatographic/mass spectrometric (GC/MS) techniques for the analysis of the extractable semivolatile priority pollutants. The document presents...

322

Analysis of short-chain acids from bacteria by gas-liquid chromatography with a fused-silica capillary column.  

PubMed Central

The use of a flexible, fused-silica capillary column for gas-liquid chromatographic analysis of short-chain acids from bacteria is illustrated with a standard acid mixture and with a derivatized extract of culture medium from Clostridium difficile. PMID:7068826

Moss, C W; Nunez-Montiel, O L

1982-01-01

323

Silver ion chromatography using solid-phase ex- traction columns packed with a bonded-sulfonic acid phase  

Microsoft Academic Search

Commercial solid-phase extraction columns packed with a stationary phase with bonded benzenesulfonic acid groups are readily converted to the silver ion form and can then be used for silver ion chromatography of lipids. To illustrate the utility of such procedures, methyl ester derivatives of fatty acids with zero to six double bonds were separated from each other by a simple

William W. Christie

324

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

325

W.P. Davies Newspaper Columns  

NSDL National Science Digital Library

Born on a farm in Ontario, William Preston Davies came to the plains of North Dakota at the age of 20. In his early 30s, he began a long career as a journalist, and worked as an editor and writer at the Northwest News, the Grand Forks Plaindealer, and the Grand Forks Herald. In 1930, Davies began writing a daily column called "That Reminds Me". This digital collection from the University of North Dakota's Chester Fritz Library gives users access to his daily insights and observations on North Dakota life. The first column available here dates from April 1930 and the last one is from September 1943. There is nary a subject that Davies doesn't cover, as he winds his way through topics like farm policy, local wit and lore, and Charlie Chaplin.

326

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

327

Combination of solid phase extraction and surface-enhanced Raman spectroscopy for rapid analysis.  

PubMed

A surface-enhanced Raman spectroscopy (SERS)-active extraction column based on propanethiol modified silver dendrites was fabricated. The column, which combines the advantages of solid phase extraction and SERS, may facilitate the development of rapid analysis with high reliability and accuracy. High temporal stability (under a continuous and intensive laser radiation) and excellent repeatability (repeated extraction and elution) were also achieved using this column. As an example, the quantitative analysis of fluoranthene was accomplished in the concentration range of 0.01-100 ?g mL(-1) with this column. The extraction process could be accomplished in 10 s and the total time of one sample analysis including extraction, spectral acquisition, elution and intermediate process could be less than 30 s. This method can greatly simplify the sample preparation and reduce the total analysis time. PMID:23476920

Lai, Yongchao; Cui, Jingcheng; Jiang, Xiaohong; Zhu, Sha; Zhan, Jinhua

2013-05-01

328

Cadmium removal in a biosorption column  

Microsoft Academic Search

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

B. Volesky; I. Prasetyo

1994-01-01

329

Modular evolution of the Cetacean vertebral column.  

PubMed

Modular theory predicts that hierarchical developmental processes generate hierarchical phenotypic units that are capable of independent modification. The vertebral column is an overtly modular structure, and its rapid phenotypic transformation in cetacean evolution provides a case study for modularity. Terrestrial mammals have five morphologically discrete vertebral series that are now known to be coincident with Hox gene expression patterns. Here, I present the hypothesis that in living Carnivora and Artiodactyla, and by inference in the terrestrial ancestors of whales, the series are themselves components of larger precaudal and caudal modular units. Column morphology in a series of fossil and living whales is used to predict the type and sequence of developmental changes responsible for modification of that ancestral pattern. Developmental innovations inferred include independent meristic additions to the precaudal column in basal archaeocetes and basilosaurids, stepwise homeotic reduction of the sacral series in protocetids, and dissociation of the caudal series into anterior tail and fluke subunits in basilosaurids. The most dramatic change was the novel association of lumbar and anterior caudal vertebrae in a module that crosses the precaudal/caudal boundary. This large unit is defined by shared patterns of vertebral morphology, count, and size in all living whales (Neoceti). PMID:17501751

Buchholtz, Emily A

2007-01-01

330

[Spectral investigation of atmospheric pressure plasma column].  

PubMed

Atmospheric pressure plasma column has many important applications in plasma stealth for aircraft. In the present paper, a plasma column with a length of 65 cm was generated in argon at atmospheric pressure by using dielectric barrier discharge device with water electrodes in coaxial configurations. The discharge mechanism of the plasma column was studied by optical method and the result indicates that a moving layer of light emission propagates in the upstream region. The propagation velocity of the plasma bullet is about 0.6 x 10(5) m x s(-1) through optical measurement. Spectral intensity ratios as functions of the applied voltage and driving frequency were also investigated by spectroscopic method. The variation in spectral intensity ratio implies a change in the averaged electron energy. Results show that the averaged electron energy increases with the increase in the applied voltage and the driving frequency. These results have significant values for industrial applications of the atmospheric pressure discharge and have extensive application potentials in stealth for military aircraft. PMID:23016319

Li, Xue-Chen; Chang, Yuan-Yuan; Xu, Long-Fei

2012-07-01

331

SPEEDUP{trademark} ion exchange column model  

SciTech Connect

A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUp{trademark} software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLig{trademark} ion exchange resins, once the experimental data are complete.

Hang, T.

2000-03-06

332

Dynamic pulse difference circuit  

Microsoft Academic Search

A digital electronic circuit of especial use for subtracting background activity pulses in gamma spectrometry comprises an up-down counter connected to count up with signal-channel pulses and to count down with background-channel pulses. A detector responsive to the count position of the up-down counter provides a signal when the up-down counter has completed one scaling sequence cycle of counts in

Gerald L

1978-01-01

333

Dynamic pulse difference circuit  

Microsoft Academic Search

A digital electronic circuit of especial use for subtracting background activity pulses in gamma spectrometry is disclosed which comprises an up-down counter connected to count up with signal-channel pulses and to count down with background-channel pulses. A detector responsive to the count position of the up-down counter provides a signal when the up-down counter has completed one scaling sequence cycle

1978-01-01

334

PulseSoar  

SciTech Connect

This paper is an introduction to the PulseSoar concept. PulseSoar is a hypervelocity airplane that uses existing airport facilities and current technologies to fly at the very edge of space. It will be shown that PulseSoar can fly between any two points on the globe in less than two hours with fuel efficiency exceeding current state of the art commercial airliners. In addition, it will be shown that PulseSoar avoids environmental issues concerning the ozone layer and sonic booms because of its unique flight profile. All of this can be achieved with current technology. PulseSoar does not require the development of enabling technology. It is a concept which can be demonstrated today. The importance of this idea goes beyond the technical significance`s of PulseSoar in terms of feasibility and performance. PulseSoar could provide a crucial economic advantage to America`s largest export market: commercial aircraft. PulseSoar is a breakthrough concept for addressing the emerging markets of long range and high speed aircraft. Application of PulseSoar to commercial transport could provide the US Aerospace industry a substantial lead in offering high speed/long range aircraft to the world`s airlines. The rapid emergence of a US developed high speed aircraft could also be important to our competitiveness in the Pacific Rim and South American economies. A quick and inexpensive demonstration vehicle is proposed to bang the concept to reality within two years. This discussion will address all the major technical subjects encompassed by PulseSoar and identifies several near-term, and low risk, applications which may be further explored with the initial demonstration vehicle. What is PulseSoar? PulseSoar could enable high speed, high altitude and long range flight without many of the difficulties encountered by traditional hypersonic vehicles.

Carter, P.; Peglow, S.

1992-07-21

335

Focused ultrasound solid-liquid extraction for the determination of perfluorinated compounds in fish, vegetables and amended soil.  

PubMed

In the present work a method was developed for the determination of different perfluorinated compounds (PFCs), including three perfluorinated sulfonic acids (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA) in fish, vegetables and amended soil samples based on focused ultrasound solid-liquid extraction (FUSLE) followed by solid-phase extraction (SPE) clean-up and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Different variables affecting the chromatographic separation (column type and pH of the mobile phase), the electrospray ionization (capillary voltage, nebulizer pressure and drying gas flow) and mass spectrometric detection (fragmentor voltage and collision energy) were optimized in order to improve the sensitivity of the separation and detection steps. In the case of FUSLE variables such as the solvent type, the solvent volume, the extraction temperature, the sonication and extraction time and the percentage of applied irradiation power were studied. Under optimized conditions, sonication of 2.5min with pulse times on of 0.8s and pulse times off of 0.2s in 7mL of (9:1) acetonitrile (ACN): water mixture in duplicate guaranteed exhaustive extraction of the matrices analyzed. Due to the non-selective extraction using FUSLE, different SPE cartridges (200-mg Waters Oasis-HLB, 150-mg Waters Oasis-WAX and 150-mg Waters Oasis-MAX) were tested in terms of extraction efficiency and matrix effect both in the extraction and detection steps. Mix mode SPE using Waters Oasis-WAX provided the best extraction efficiencies with the lowest matrix effect. The final method was validated in terms of recovery at two fortification levels (in the 80-120% for most of the analytes and matrices), precision (relative standard deviation in the 2-15% range) and method detection limits (MDLs, 0.3-12.4ng/g for vegetables, 0.2-12.5ng/g for fish and 1-22ng/g for amended soil). Finally the method was applied for the determination of the 14 PFCs in different vegetables and fish samples from a local supermarket and in a soil amended with a compost from a local wastewater treatment plant (WWTP). PMID:24495790

Zabaleta, Itsaso; Bizkarguenaga, Ekhiñe; Iparragirre, Arantza; Navarro, Patricia; Prieto, Ailette; Fernández, Luis Ángel; Zuloaga, Olatz

2014-02-28

336

Extraction of uranium: comparison of stripping with ammonia vs. strong acid  

SciTech Connect

Following extraction of uranium in the first stage of solvent extraction using a tertiary amine, typically Alamine 336, the stripping of the extracted uranium is accomplished either by use of an aqueous solution of (NH{sub 4}){sub 2}SO{sub 4} /NH{sub 4}OH or by strong-acid stripping using 400-500 g/L H{sub 2}SO{sub 4}. Both processes have their merits and determine the downstream processing. The classical stripping with ammonia is followed by addition of strong base, to precipitate ammonium uranyl sulfate (NH{sub 4}){sub 2}UO{sub 2}(SO{sub 4}){sub 2}, which yields finally the yellow cake. Conversely, stripping with H{sub 2}SO{sub 4}, followed by oxidation with hydrogen peroxide yields uranyl oxide as product. At the Cameco Key Lake operation, both processes were tested on a pilot scale, using a Bateman Pulsed Column (BPC). The BPC proved to be applicable to both processes. It met the process criteria both for extraction and stripping, leaving less than 1 mg/L of U{sub 3}O{sub 8} in the raffinate, and product solution had the required concentration of U{sub 3}O{sub 8} at high flux and reasonable height of transfer unit. In the Key Lake mill, each operation can be carried out in a single column. The main advantages of the strong-acid stripping over ammonia stripping are: (1) 60% higher flux in the extraction, (2) tenfold higher concentration of the uranium in the product solution, and (3) far more robust process, with no need of pH control in the stripping and no need to add acid to the extraction in order to keep the pH above the point of precipitation of iron compounds. The advantages of the ammoniacal process are easier stripping, that is, less stages needed to reach equilibrium and lower concentration of modifier needed to prevent the creation of a third phase. (authors)

Moldovan, B. [Cameco Corporation (Canada); Grinbaum, B.; Efraim, A. [Bateman Solvent Extraction (Israel)

2008-07-01

337

Critical pulse power components  

SciTech Connect

Critical components for pulsed power conditioning systems will be reviewed. Particular emphasis will be placed on those components requiring significant development efforts. Capacitors, for example, are one of the weakest elements in high-power pulsed systems, especially when operation at high-repetition frequencies for extended periods of time are necessary. Switches are by far the weakest active components of pulse power systems. In particular, opening switches are essentially nonexistent for most applications. Insulaton in all systems and components requires development and improvement. Efforts under way in technology base development of pulse power components will be discussed.

Sarjeant, W.J.; Rohwein, G.J.

1981-01-01

338

Controlling output pulse and prepulse in a resonant microwave pulse compressor  

NASA Astrophysics Data System (ADS)

A resonant microwave pulse compressor with a waveguide H-plane-tee-based energy extraction unit was studied in terms of its capability to produce output pulses that comprise a low-power long-duration (prepulse) and a high-power short-duration part. The application of such combined pulses with widely variable prepulse and high-power pulse power and energy ratios is of interest in the research area of electronic hardware vulnerability. The characteristics of output radiation pulses are controlled by the variation of the H-plane tee transition attenuation at the stage of microwave energy storage in the compressor cavity. Results of theoretical estimations of the parameters tuning range and experimental investigations of the prototype S-band compressor (1.5 MW, 12 ns output pulse; ˜13.2 dB gain) are presented. The achievable maximum in the prepulse power is found to be about half the power of the primary microwave source. It has been shown that the energy of the prepulse becomes comparable with that of the short-duration (nanosecond) pulse, while the power of the latter decreases insignificantly. The possible range of variation of the prepulse power and energy can be as wide as 40 dB. In the experiments, the prepulse level control within the range of ˜10 dB was demonstrated.

Shlapakovski, A.; Artemenko, S.; Chumerin, P.; Yushkov, Yu.

2013-02-01

339

Enhanced phytoremediation in the vadose zone: Modeling and column studies  

NASA Astrophysics Data System (ADS)

Phytoremediation is a plant-based technique with potential for enhancing the remediation of vadoese zone soils contaminated by pollutants. The use of deep-rooted plants is an alternative to conventional methodologies. However, when the phytoremediation is applied to the vadose zone, it might have some restrictions since it uses solely naturally driven energy and mechanisms in addition to the complesxity of the vadose zone. As a more innovative technique than conventional phytoremediation methods, air injected phytoremediation technique is introduced to enhance the remediation efficiency or to apply at the former soil vapor extraction or bio venting sites. Effects of air injection, vegetation treatment, and air injection with vegetation treatments on the removal of hydrocarbon were investigated by column studies to simulate the field situation. Both the removal efficiency and the microbial activity were highest in air-injected and vegetated column soils. It was suggested that increased microorganisms activity stimulated by plant root exudates enhanced biodegradation of hydrocarbon compounds. Air injection provided sufficient opportunity for promoting the microbial activity at depths where the conditions are anaerobic. Air injection can enhance the physicochemical properties of the medium and contaminant and increase the bioavailability i.e., the plant and microbial accessibility to the contaminant. A mathematical model that can be applied to phytoremediation, especially to air injected phytoremediation, for simulating the fate and the transport of a diesel contaminant in the vadose zone is developed. The approach includes a two-phase model of water flow in vegetated and unplanted vadose zone soil. A time-specific root distribution model and a microbial growth model in the rhizosphere of vegetated soil were combined with an unsaturated soil water flow equation as well as with a contaminant transport equation. The proposed model showed a satisfactory representation of contaminant fate in the air injected phytoremediation.

Sung, K.; Chang, Y.; Corapcioglu, M.; Cho, C.

2002-05-01

340

Fast Pulsing Neutron Generators for Security Application  

SciTech Connect

Active neutron interrogation has been demonstrated to be an effective method of detecting shielded fissile material. A fast fall-time/fast pulsing neutron generator is needed primarily for differential die-away technique (DDA) interrogation systems. A compact neutron generator, currently being developed in Lawrence Berkeley National Laboratory, employs an array of 0.6-mm-dia apertures (instead of one 6-mm-dia aperture) such that gating the beamlets can be done with low voltage and a small gap to achieve sub-microsecond ion beam fall time and low background neutrons. Arrays of 16 apertures (4x4) and 100 apertures (10x10) have been designed and fabricated for a beam extraction experiment. The preliminary results showed that, using a gating voltage of 1200 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is approximately 0.15 mu s at beam energies of 1000 eV.

Ji, Q.; Regis, M.; Kwan, J. W.

2009-04-24

341

Developing the Pulsed Fission-Fusion (PuFF) Engine  

NASA Technical Reports Server (NTRS)

In September 2013 the NASA Innovative Advanced Concept (NIAC) organization awarded a phase I contract to the PuFF team. Our phase 1 proposal researched a pulsed fission-fusion propulsion system that compressed a target of deuterium (D) and tritium (T) as a mixture in a column, surrounded concentrically by Uranium. The target is surrounded by liquid lithium. A high power current would flow down the liquid lithium and the resulting Lorentz force would compress the column by roughly a factor of 10. The compressed column would reach criticality and a combination of fission and fusion reactions would occur. Our Phase I results, summarized herein, review our estimates of engine and vehicle performance, our work to date to model the fission-fusion reaction, and our initial efforts in experimental analysis.

Adams, Robert B.; Cassibry, Jason; Bradley, David; Fabisinski, Leo; Statham, Geoffrey

2014-01-01

342

Query execution in column-oriented database systems  

E-print Network

There are two obvious ways to map a two-dimension relational database table onto a one-dimensional storage interface: store the table row-by-row, or store the table column-by-column. Historically, database system implementations ...

Abadi, Daniel J

2008-01-01

343

18. VIEW SOUTH OF TIMBER COLUMNS ON FIRST FLOOR OF ...  

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

18. VIEW SOUTH OF TIMBER COLUMNS ON FIRST FLOOR OF BUILDING 21 SHOWING TYPICAL MILL CONSTRUCTION; COLUMNS REST ON CAST IRON BASE PLATES - Scovill Brass Works, 59 Mill Street, Waterbury, New Haven County, CT

344

46 CFR 174.085 - Flooding on column stabilized units.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Flooding on column stabilized units. 174...Offshore Drilling Units § 174.085 Flooding on column stabilized units. ...unit, must be assumed to be subject to flooding as follows: (1) When a...

2012-10-01

345

46 CFR 174.085 - Flooding on column stabilized units.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Flooding on column stabilized units. 174...Offshore Drilling Units § 174.085 Flooding on column stabilized units. ...unit, must be assumed to be subject to flooding as follows: (1) When a...

2011-10-01

346

46 CFR 174.085 - Flooding on column stabilized units.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Flooding on column stabilized units. 174...Offshore Drilling Units § 174.085 Flooding on column stabilized units. ...unit, must be assumed to be subject to flooding as follows: (1) When a...

2013-10-01

347

46 CFR 174.085 - Flooding on column stabilized units.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Flooding on column stabilized units. 174...Offshore Drilling Units § 174.085 Flooding on column stabilized units. ...unit, must be assumed to be subject to flooding as follows: (1) When a...

2010-10-01

348

3. Detail of beam splice and column capital on the ...  

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

3. Detail of beam splice and column capital on the second floor of the Cloth Room Building/Old Bleach House, Monadnock Mills. Beam and column edges are chamfered. - Monadnock Mills, 15 Water Street, Claremont, Sullivan County, NH

349

Displacement Demand Effects in Vulnerable Reinforced Concrete Columns  

E-print Network

to both columns while being subjected to lateral deformations with increasing amplitude, until both lateral and axial load capacities were lost. Post-failure measurements were obtained to study the residual strength of the columns. Results show that all...

Woods, Charles

2010-06-01

350

19. Detail of builtup 5" x 13" column at fruit ...  

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

19. Detail of built-up 5" x 13" column at fruit and vegetable storage room; note ledger plates bolted to top of column - Fort Hood, World War II Temporary Buildings, Cold Storage Building, Seventeenth Street, Killeen, Bell County, TX

351

CAR MACHINE SHOP, FIRST FLOOR, DETAIL OF WOOD COLUMN AND ...  

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

CAR MACHINE SHOP, FIRST FLOOR, DETAIL OF WOOD COLUMN AND INVERTED KING-POST TRUSS TO PROVIDE INCREASED SPAN BETWEEN COLUMNS, LOOKING SOUTH. - Southern Pacific, Sacramento Shops, Car Machine Shop, 111 I Street, Sacramento, Sacramento County, CA

352

A Case of Polymyxin b-Immobilized Fiber Column Treatment for Rapidly Progressive Interstitial Pneumonia Associated with Clinically Amyopathic Dermatomyositis  

PubMed Central

We report a case of rapidly progressive interstitial pneumonia associated with clinically amyopathic dermatomyositis who responded to single course of polymyxin b-immobilized fiber column treatment. Initial treatment with pulsed corticosteroids and cyclophosphamide, intravenous immunoglobulin, and cyclosporine seemed to suppress the activity of interstitial lung disease temporarily, but signs of relapse were detected such as elevation of serum KL-6 level and progressing pulmonary shadows in chest computed tomography scan. After polymyxin b-immobilized fiber column treatment, the areas of pulmonary shadows drastically decreased. Gradually, arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio recovered, and serum ferritin level and KL-6 level decreased. These findings indicate that polymyxin b-immobilized fiber column treatment could be promising in combination with conventional therapy for rapidly progressive interstitial pneumonia associated with clinically amyopathic dermatomyositis, especially at the early phase of relapse. PMID:23983712

2013-01-01

353

Quantitative determination of 11-nor-9-carboxy-tetrahydrocannabinol in hair by column switching LC-ESI-MS(3).  

PubMed

Hair analysis has been regarded as an alternative method to urine analysis in forensic and criminal cases. Cannabis (marijuana) is one of the most widely used drugs in the world and it has been controlled in South Korea since 1976. Identification of 11-nor-9-carboxy-tetrahydrocannabinol (THCCOOH) in hair can be an important proof of cannabis use because it can exclude the possibility of passive cannabis smoke exposure. In this study, we described a quantitative method of THCCOOH in hair using simple liquid-liquid extraction (LLE), selective column switching liquid chromatography with electrospray ionization (ESI)-MS(3). For the column switching system three columns (precolumn, trap column and analytical column) were used. Valve switch from the precolumn to the trap column was set from 3.0 to 4.0 min because THCCOOH appeared around 3.5 min with this precolumn. After 4.0 min the valve was switched to the original position and the analytes in the trap column were eluted onto the analytical column. Resolution occurred in this column and eluted into the ESI-MS(3) system. The internal standard was THCCOOH-d3. We used ESI-negative-MS(3) transition of ions at m/z 343 to 299 to 245 (343/299/245) and m/z 346 to 302 to 248 (346/302/248) for quantification of THCCOOH and THCCOOH-d3, respectively. The validation results of selectivity, matrix effect, recovery, linearity, precision and accuracy, and processed sample stability were satisfactory. The limit of detection (LOD) was 0.05 pg/mg and the limit of quantification (LOQ) was 0.10 pg/mg. The range of concentration of THCCOOH from 98 authentic human hair was 0.13-15.75 pg/mg. This method was successfully applied in the analysis of authentic human hair samples. PMID:24434565

Park, Meejung; Kim, Jihyun; Park, Yuran; In, Sanghwan; Kim, Eunmi; Park, Yonghoon

2014-02-01

354

DNA Extraction  

NSDL National Science Digital Library

In this activity related to plant biotechnology, learners extract DNA from fruit to investigate how it looks and feels. The procedure is similar to what scientists have to do before they can use information contained in this DNA. This lesson guide includes procedure and discussion questions to help learners reflect on the process and purpose of DNA extraction. Modifications for younger learners are included in a related PDF (see related resources).

Stephens, Janice; Leach, Jan

2011-01-01

355

Cross flow cyclonic flotation column for coal and minerals beneficiation  

DOEpatents

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 a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophillic tailings.

Lai, Ralph W. (Upper St. Clair, PA); Patton, Robert A. (Pittsburgh, PA)

2000-01-01

356

Cross flow flotation column for coal and minerals beneficiation  

SciTech Connect

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 to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophilic tailings.

Lai, Ralph W.; Patton, Robert A.

1997-12-01

357

Cross flow cyclonic flotation column for coal and minerals beneficiation  

SciTech Connect

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 to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophilic tailings.

Lai, R.W.; Patton, R.A.

2000-05-02

358

Column strength of magnesium alloy AM-57S  

NASA Technical Reports Server (NTRS)

Tests were made to determine the column strength of extruded magnesium alloy AM-57S. Column specimens were tested with round ends and with flat ends. It was found that the compressive properties should be used in computations for column strengths rather than the tensile properties because the compressive yield strength was approximately one-half the tensile yield strength. A formula for the column strength of magnesium alloy AM-57S is given.

Holt, M

1942-01-01

359

An investigation of the optics of an accelerating column for use with a high brightness ion source and a proton microprobe  

NASA Astrophysics Data System (ADS)

The accelerating column of a 5U Pelletron accelerator is analysed in this paper. This accelerator provides the primary beam for the Melbourne Scanning Proton Microprobe. The finite element method is used to calculate the electrostatic field in the accelerator column, and optical properties are extracted from ray tracing. Gaussian properties are presented which specify object location for the column to produce an exit plane focus for five and three accelerating elements. Column acceptance is discussed and found to match emittance for all practical configurations. Chromatic and spherical aberrations are calculated for the column for a range of image distances and for five and three accelerating elements. The optical combination of the column with an ion source lens and a high brightness ion source is discussed. The contribution of the column is found to be principally dependent on the magnification and accelerating voltage of the lens. Where very low currents are required from the accelerator, beam brightness is limited by chromatic aberration, and for very low divergences by diffraction. At such currents the high brightness phase space "core" of the beam may be degraded by chromatic aberration in the accelerating column if the ion source lens magnification is low, or the lens acceleration is particularly high. Where high currents are required (for example above 100 pA), beam divergence angles are higher, and the brightness is no longer chromatically or diffraction limited. Under these circumstances, accelerating column aberrations will not degrade beam brightness.

Colman, R. A.; Legge, G. J. F.

1993-04-01

360

COLLOCATION METHODS FOR DISTILLATION DESIGN III: FLEXIBLE COLUMN DESIGN  

Microsoft Academic Search

In this third paper on collocation methods for distillation design, we explore the use of the collocation models for design of simple distillation columns as well as flexible columns. Solvent recovery plants must deal with a wide range of feeds and still return pure solvents. The design problem we address is a single flexible column within the overall solvent recovery

Robert S. Huss; Arthur W. Westerberg

361

ITER relevant testing of a cryogenic distillation column system  

Microsoft Academic Search

A new experimental system has been constructed to test ITER relevant distillation columns and related cryogenic distillation (CD) hardware and control systems. These columns are used to purify tritium in the ITER fuel cycle. The ITER test column reported here has a diameter of about 30 mm and a packed length of approximately 150 cm. It can operate with a

D. G. Bellamy; J. R. Robins; K. B. Woodall; S. K. Sood; P. Gierszewski

1995-01-01

362

Using thermally coupled reactive distillation columns in biodiesel production  

Microsoft Academic Search

Production of methyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillation sequences may consume less energy

Nghi Nguyen; Ya?ar Demirel

2011-01-01

363

Water hammer with column separation: A historical review  

Microsoft Academic Search

Column separation refers to the breaking of liquid columns in fully filled pipelines. This may occur in a water-hammer event when the pressure in a pipeline drops to the vapor pressure at specific locations such as closed ends, high points or knees (changes in pipe slope). The liquid columns are separated by a vapor cavity that grows and diminishes according

A. Bergant; A. R. Simpson; A. S. Tijsseling

2006-01-01

364

Lability of trace metals in submerged soils: a column study  

NASA Astrophysics Data System (ADS)

The reduction of Fe (III) and Mn (IV) and the decomposition of organic matter exert a great influence on the biogeochemical cycles of many trace metals and nutrients in the environment. In the particular case of intermittently submerged soils, metals associated with Fe and Mn oxides become readily available due to the reductive dissolution of Fe and Mn oxides. The effects of oxido-reductive conditions on the release of Cu and Zn from heavy metal contaminated soils and the changes in their chemical speciation were studied. Column experiments were performed, using Rhizon soil moisture samplers inserted at different heights to monitor the mobility and transport of metals in the submerged soil samples. Cu was released in solution immediately, in the first red-ox cycle, either due to the solubilization of Fe and Mn oxides, or to the oxidation of organic matter with which Cu is commonly complexed, or both. During the following reductive half-cycles, the amount of Cu extracted from the soil solution decreased. However, the concentration of Cu in the solution leached from the column, which was percolated in aerobic conditions, increased. Since in the successive red-ox cycles the Eh decreases faster and to lower values, it is possible that Cu might have been removed from pore water by sulfide precipitation during the anaerobic half-cycle and released during the aerobic half-cycle, due to the oxidation of sulfides to sulfates. The release of Zn was similar to the dissolution of Fe and Mn oxyhydroxydes, and the amount extracted by Rhizon and by leaching increased during the four red-ox cycles. The chemical fractionation of the soils was also studied and the results showed that the alternate oxidative-reductive conditions cause, in general, an increase in the lability of trace metals. While Zn speciation suffers little change, Cu showed a much higher exchangeable fraction in the submerged soils, as compared to the initial, not submerged ones. The results of this study indicate that intermittent submergence of contaminated soils not only causes the release of trace metals previously bound to Fe and Mn oxides and to organic matter, but also leads to an increase in their lability, rending them more readily available to be released into the environment.

Nimirciag, Ramona; Ajmone-Marsan, Franco

2013-04-01

365

Pulsed Fission Propulsion Concept  

NASA Technical Reports Server (NTRS)

In the 1960's U.S. Government laboratories, under Project Orion, investigated a pulsed nuclear fission propulsion system. Small nuclear pulse units would be sequentially discharged from the aft end of the vehicle. A blast shield and shock absorber system would protect the crew and convert the shock loads into a continuous propusive force.

1999-01-01

366

Pulsed Fission Propulsion Concept  

NASA Technical Reports Server (NTRS)

In the 1960's U.S. Government laboratories, under Project Orion, investigated a pulsed nuclear fission propulsion system. Small nuclear pulse units would be sequentially discharged from the aft end of the vehicle. A blast shield and shock absorber system would protect the crew and convert the shock loads into a continuous propulsive force.

1999-01-01

367

Pulsed Laser Tissue Interaction  

NASA Astrophysics Data System (ADS)

Pulsed lasers, by virtue of their ability to deliver energy in a spatially and temporally confined fashion, are able to micromachine biological tissues. The clinical success of pulsed laser treatment, however, is often limited by the extent of damage that is caused to the tissue in the vicinity of the ablation crater. In general, pulsed ablation is a trade off between thermal damage to surrounding tissue, caused by relatively long pulses (>100 ms), and mechanical damage to surrounding tissue, caused by relatively short pulses (<1 ms). To identify the origin of pulsed laser induced damage, the possible laser tissue interactions and ablation are discussed here and in Chapter 14. The purpose of this chapter is to provide the reader with a condensed overview of the parameters that must be considered in the process of pulsed laser ablation of soft tissue. In this chapter, pulsed infrared ablation of biological soft tissue is used as a paradigm to illustrate the concepts and design considerations. Generally speaking, the absorption of laser light may lead to photothermal, photomechanical or photochemical interaction with the irradiated tissue [1-5]. The vast majority of therapeutic laser-tissue interactions is based on photothermal interactions where laser energy is converted into heat. Subsequent to thermalization of the absorbed optical energy, heat transfer mechanisms, in particular conduction allow thermal diffusion from high temperature areas to surrounding regions. When laser penetration depth is less than the laser spot radius, the thermal diffusion time, ? th, can be defined as:

Walsh, Joseph T.; van Leeuwen, Ton G.; Jansen, E. Duco; Motamedi, Massoud; Welch, Ashley J.

368

Bipolar pulse generator for intense pulsed ion beam accelerator  

NASA Astrophysics Data System (ADS)

A new type of pulsed ion beam accelerator named "bipolar pulse accelerator" (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138kV, 72ns) and the second pulse (+130kV, 70ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time.

Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K.

2007-01-01

369

Chirped pulse Raman amplifier  

NASA Astrophysics Data System (ADS)

All modern terawatt- and petawatt-class laser systems are based on the principle of chirped-pulse amplification (CPA). In this work, a compact subsystem that shifts a micro-joule portion of the chirped pulse energy to a new wavelength outside its original bandwidth, then amplifies it to millijoule energy without adding pump lasers, and without compromising the output of the fundamental CPA system in any significant way, has been developed and integrated into a standard terawatt-class CPA system. In this chirped pulse Raman amplifier sub-system, a 30 mJ portion of a chirped 800 nm fundamental pulse within the CPA system was split into two unequal portions, each of which impinged on a Raman-active barium nitrate, or Ba(NO3)2, crystal of length 5 cm. The weaker portion created a weak (15 J) first Stokes pulse (873 nm) by Stimulated Raman Scattering (SRS) in the first crystal, which then seeded a non-collinear four-wave-mixing process driven by the stronger portion of the split-off CPA pulse in the second crystal. The latter process amplified the first Stokes seed pulse to several millijoules with excellent beam quality. A study of Raman gain as a function of time delay between pump and Stokes pulse in the second crystal revealed a sharply peaked narrow interval (˜3 ps FWHM) of high gain and a wider interval (˜50 ps) of low gain. The amplified, chirped first Stokes pulse was successfully compressed to 100 fs duration using a grating pair of different line density than in the main CPA system, based on a comprehensive dispersion analysis of the optical path of the first Stokes pulse. The possibility of generating higher-order Stokes and anti-Stokes sidebands of the CPA pulse is also demonstrated. Further amplification of the sideband pulse by conventional methods, using an additional pump laser, appears straightforward. The chirped pulse Raman amplifier provides temporally synchronized fundamental and Raman sideband pulses for performing two-color, high-intensity laser experiments, some of which are briefly discussed. It can be integrated into any standard CPA system, and provides significant new versatility for high-intensity laser sources.

Grigsby, Franklin Bhogaraju

370

Stress Analysis of Columns and Beam Columns by the Photoelastic Method  

NASA Technical Reports Server (NTRS)

Principles of similarity and other factors in the design of models for photoelastic testing are discussed. Some approximate theoretical equations, useful in the analysis of results obtained from photoelastic tests are derived. Examples of the use of photoelastic techniques and the analysis of results as applied to uniform and tapered beam columns, circular rings, and statically indeterminate frames, are given. It is concluded that this method is an effective tool for the analysis of structures in which column action is present, particularly in tapered beam columns, and in statically indeterminate structures in which the distribution of loads in the structures is influenced by bending moments due to axial loads in one or more members.

Ruffner, B F

1946-01-01

371

Localized wave pulse experiments  

SciTech Connect

The Localized Wave project of the Strategic System Support Program has recently finished an experiment in cooperation with the Advanced SONAR group of the Applied Research Laboratory of the University of Texas at Austin. The purpose of the experiment was three-fold. They wanted to see if (1) the LW pulse could propagate over significant distances, to see if (2) a new type of array and drive system specifically designed for the pulse would increase efficiency over single frequency tone bursts, and to see if (3) the complexity of our 24 channel drivers resulted in better efficiency than a single equivalent pulse driving a piston. In the experiment, several LW pulses were launched from the Lake Travis facility and propagated over distances of either 100 feet or 600 feet, through a thermocline for the 600 foot measurements. The results show conclusively that the Localized Wave will propagate past the near field distance. The LW pulses resulted in extremely broad frequency band width pulses with narrow spatial beam patterns and unmeasurable side lobes. Their array gain was better than most tone bursts and further, were better than their equivalent piston pulses. This marks the first test of several Low Diffraction beams against their equivalent piston pulses, as well as the first propagation of LW pulses over appreciable distances. The LW pulse is now proven a useful tool in open water, rather than a laboratory curiosity. The experimental system and array were built by ARL, and the experiments were conducted by ARL staff on their standard test range. The 600 feet measurements were made at the farthest extent of that range.

Chambers, D L; Henderson, T L; Krueger, K L; Lewis, D K; Zilkowski, R N

1999-06-01

372

A review of oscillating water columns.  

PubMed

This paper considers the history of oscillating water column (OWC) systems from whistling buoys to grid-connected power generation systems. The power conversion from the wave resource through to electricity via pneumatic and shaft power is discussed in general terms and with specific reference to Voith Hydro Wavegen's land installed marine energy transformer (LIMPET) plant on the Scottish island of Islay and OWC breakwater systems. A report on the progress of other OWC systems and power take-off units under commercial development is given, and the particular challenges faced by OWC developers reviewed. PMID:22184660

Heath, T V

2012-01-28

373

Tropospheric NO2 column densities deduced from zenith-sky DOAS measurements in Shanghai, China, and their application to satellite validation  

Microsoft Academic Search

Zenith-sky scattered sunlight observations using differential optical absorption spectroscopy (DOAS) technique were carried out in Shanghai, China (31.3° N, 121.5° E) since December 2006. At this polluted urban site, the measurement provided NO2 total columns in the daytime. Here, we present a new method to extract time series of tropospheric vertical column densities (VCD) of NO2 from these observations. The

D. Chen; B. Zhou; S. Beirle; L. M. Chen; T. Wagner

2008-01-01

374

9. Detail view of columns on first floor. This row ...  

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

9. Detail view of columns on first floor. This row of columns indicates the former location of the exterior mill wall before World War II era expansion. The unusual column and beam connection was a key part of the mill structural system patented by Providence, Rhode Island engineers Charles Praray and Charles Makepeace in 1894. Each column was originally located in the apex of triangular window bay, but not connected to the exterior wall. Modifications on the right side of each column support the beams of the addition. - Dixie Cotton Mill, 710 Greenville Street, La Grange, Troup County, GA

375

Identification of flow regime in a slurry bubble column by Hilbert-Huang transform analysis  

NASA Astrophysics Data System (ADS)

Experiments were conducted in a two-dimensional (2-D) slurry bubble column, which had a length of 0.1m, a width of 0.01m and a total height of 0.8m. The gas phase was oil-free air, tap water was used as the liquid phase, glass powders with particle diameter of 58?m-75?m constituted the solid phase, which belonged to the Geldart A particles. Time-domain analysis and the Hilbert-Huang transform methods were employed to analyze the differential pressure signals obtained and to identify the transition points of the flow regimes in the slurry bubble column. Useful qualitative and quantitative information about the changes in flow structure and particle distributions were extracted. Changes in the standard deviation, skewness and flatness of measured pressure time series with superficial gas velocity are proposed. Hilbert-Huang transform was applied to extract information from signals, and flow structures of the slurry bubble column were characterized by the energy distribution of the multi-resolution signals and the EMD energy entropy. Particle distributions were obtained and analyzed from flow pattern images.

Li, Weiling; Zhong, Wenqi; Jin, Baosheng; Xiao, Rui

2013-06-01

376

Simultaneous determination of methamphetamine and its metabolite, amphetamine, in urine using a high performance liquid chromatography column-switching method.  

PubMed

We describe here a simple, precise, and highly sensitive method for the simultaneous determination of methamphetamine (MA) and amphetamine (AM) in urine using a high performance liquid chromatography (HPLC) column-switching method. A PK-2A (Shodex) column was used for extraction and deproteinization, and a CAPCELL PAK SCX semi-micro, polymer-coated cation-exchange column was employed for separation. The urine sample was mixed with an equal volume of borate buffer (0.1M, pH 9.4), and then 100 microl of the mixture was injected into the HPLC column. The column was switched for 6 min, and then 10 min later detection was performed at 210 nm. Recovery yields of the MA and AM spiked in the urine were 93.0-100.4% with a coefficient of variation of less than 1%. The calibration curves of MA and AM were in the range of 0.1-10 microg/ml with good linearity (r(2)=0.999), with the limit of qualification being 0.005 microg/ml. This method of using HPLC with column-switching can be used for both qualification and quantification of MA and its metabolite, AM, in urine, especially in forensic cases. PMID:16916628

Kumihashi, Mitsuru; Ameno, Kiyoshi; Shibayama, Takayuki; Suga, Keisuke; Miyauchi, Hiroshi; Jamal, Mostofa; Wang, Weihuan; Uekita, Ikuo; Ijiri, Iwao

2007-01-01

377

Rapid and sensitive bioanalytical method for measurement of fluvoxamine in human serum using 4-chloro-7-nitrobenzofurazan as pre-column derivatization agent: Application to a human pharmacokinetic study  

Microsoft Academic Search

A sensitive and rapid high-performance liquid chromatographic method for the analysis of fluvoxamine, a selective serotonin reuptake inhibitor in human serum, is described using 4-chloro-7-nitrobenzofurazan as pre-column derivatization agent. The drug and an internal standard (fluoxetine) were extracted from 0.25mL of serum using ethyl acetate as extracting solvent and subjected to pre-column derivatization by the reagent. A mobile phase consisting

Gholamreza Bahrami; Bahareh Mohammadi

2007-01-01

378

Determination of ochratoxin A in baby food by immunoaffinity column cleanup with liquid chromatography: interlaboratory study.  

PubMed

An interlaboratory study funded by the European Commission, Standards, Measurement and Testing Programme (4th Framework Programme) was performed to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatographic (LC) method for the determination of ochratoxin A in baby food at a possible future European regulatory limit (0.1 ng/g). The test portion is extracted in a blender with tert-butyl methyl ether (chosen to avoid use of chloroform but shown to give equivalent extraction efficiency) after addition of 0.5 mol/L phosphoric acid-2 mol/L sodium chloride solution. The extract is centrifuged and redissolved in a mixture of phosphate buffered saline solution and methanol. After removal of lypophilic substances with hexane, the extract is applied to an immunoaffinity column containing antibodies specific to ochratoxin A. The column is washed with water to remove the interfering compounds and the purified ochratoxin A is eluted with methanol. The separation and determination of ochratoxin A is performed by reversed-phase LC and detected by fluorescence after postcolumn derivatization (PCD) with ammonia. Test materials (baby food infant formulae), both spiked and naturally contaminated with ochratoxin A, were sent to 13 laboratories in 8 different European countries. Test portions were spiked at a level of 0.085 ng/g ochratoxin A. The average recovery for the spiked blank baby food was 108%. Based on results for spiked samples (blind pairs at 0.085 ng/g) as well as naturally contaminated samples (blind pairs at levels between 0.05 and 0.22 ng/g) the relative standard deviation for repeatability (RSDr) ranged from 18-36%. The relative standard deviation for reproducibility (RSDR) ranged from 29-63% and HORRAT values of between 0.4 and 0.9 were obtained. PMID:11601463

Burdaspal, P; Legarda, T M; Gilbert, J

2001-01-01

379

Fast HPLC with a silica-based monolithic ODS column.  

PubMed

Fast high-performance liquid chromatography is becoming routine in laboratories that require high throughput or for combinatorial libraries. Reduced analysis time is commonly achieved by using shorter columns and higher flow rates. Shorter columns require smaller particles in order to maintain efficiency. However, smaller particles increase backpressure, which limits both column length and higher flow rates for typical LC pumps. This disadvantage has been addressed by the emergence of monolithic liquid chromatographic columns (1). Unlike particle-base columns, monolithic columns consist of a continuous rod-shaped porous network with a bimodal pore distribution. In this study, a commercially available 50- x 4.6-mm silica-based octadecyl silane monolithic column (Chromolith SpeedROD RP18e, EM Science, Gibbstown, NJ) was used to separate a seven-component test mixture with a wide range of polarity. The primary goals of this investigation were: (a) to study the chemistry (selectivity) of the new silica-based monolithic columns and (b) to study their run-to-run and column-to-column performance (retention times and peak areas). The selectivity (alpha factor) is a ratio of partition coefficients and, if comparable for a variety of solutes, would mean that methods could be readily transferred between particulate and monolithic columns. PMID:12803810

Smith, Jennifer H; McNair, Harold M

2003-04-01

380

Extractant composition  

DOEpatents

An organic extracting solution useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form. The extracting solution consists of a primary ligand and a secondary ligand, preferably in an organic solvent. The primary ligand is a substituted monothio-1,3-dicarbonyl, which includes a substituted 4-acyl-2-pyrazolin-5-thione, such as 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT). The secondary ligand is a substituted phosphine oxide, such as trioctylphosphine oxide (TOPO).

Smith, Barbara F. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ryan, Robert R. (Los Alamos, NM)

1990-01-01

381

Monolithic columns in plant proteomics and metabolomics.  

PubMed

Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables. PMID:23224572

Rigobello-Masini, Marilda; Penteado, José Carlos Pires; Masini, Jorge Cesar

2013-03-01

382

Direct probing of chromatography columns by laser-induced fluorescence  

SciTech Connect

This report summarizes the progress and accomplishments of this research project from September 1, 1989 to February 28, 1993. During this period, we have accomplished all of the primary scientific objectives of the research proposal: (1) constructed and evaluated a laser-induced fluorescence detection system that allows direct examination of the chromatographic column, (2) examined nonequilibrium processes that occur upon solute injection and elution, (3) examined solute retention in liquid chromatography as a function of temperature and pressure, (4) examined solute zone dispersion in liquid chromatography as a function of temperature and pressure, and (5) developed appropriate theoretical models to describe these phenomena. In each of these studies, substantial knowledge has been gained of the fundamental processes that are responsible for chromatographic separations. In addition to these primary research objectives, we have made significant progress in three related areas: (1) examined pyrene as a fluorescent polarity probe insupercritical fluids and liquids as a function of temperature and pressure, (2) developed methods for the class-selective identification of polynuclear aromatic hydrocarbons in coal-derived fluids by microcolumn liquid chromatography with fluorescence quenching detection, and (3) developed methods for the determination of saturated and unsaturated (including omega-3) fatty acids in fish oil extracts by microcolumn liquid chromatography with laser-induced fluorescence detection. In these studies, the advanced separation and detection techniques developed in our laboratory are applied to practical problems of environmental and biomedical significance.

McGuffin, V.L.

1992-12-07

383

Modeling of supercritical extraction of mannitol from plane tree leaf.  

PubMed

The objective of this study was to investigate the theoretical feasibility of using supercritical fluid extraction of Mannitol from plane tree leaf as an alternative technology in the pharmaceutical industry. Simulation of an extraction column using dense liquid and supercritical carbon dioxide was modeled involving partial differential equations, using orthogonal collocation on finite elements. The important solvent extraction parameters such as the partition coefficient, mass transfer coefficient, dispersion coefficient, molecular diffusion and extraction efficiency (the amount of Mannitol extracted versus the amount of solvent used) were investigated as a function of the dimensionless Reynold's and Peclet numbers in order to optimize the extraction column geometry and the carbon dioxide operating conditions. The results of this study demonstrated that supercritical extraction is a viable technique for Mannitol production and that the process conditions for a large commercial extraction system do not require a high temperature in order to obtain a high extraction efficiency. However, at low pressures, the solubility of Mannitol in carbon dioxide would limit the success of the extraction process and at very high pressures the extraction technique may not be economically feasible. To investigate the authenticity of the mathematical model, the experimental data for the desorption of hexachlorobenzene from soil was compared with the theoretical results of this research. The model is able to predict the experimental data quite well without any adjustable parameters. PMID:11248499

Ghoreishi, S M; Sharifi, S

2001-03-01

384

Comparison of automated pre-column and post-column analysis of amino acid oligomers  

NASA Technical Reports Server (NTRS)

It has been shown that various amino acids will polymerize under plausible prebiotic conditions on mineral surfaces, such as clays and soluble salts, to form varying amounts of oligomers (n = 2-6). The investigations of these surface reactions required a quantitative method for the separation and detection of these amino acid oligomers at the picomole level in the presence of nanomole levels of the parent amino acid. In initial high-performance liquid chromatography (HPLC) studies using a classical postcolumn o-phthalaldehyde (OPA) derivatization ion-exchange HPLC procedure with fluorescence detection, problems encountered included lengthy analysis time, inadequate separation and large relative differences in sensitivity for the separated species, expressed as a variable fluorescent yield, which contributed to poor quantitation. We have compared a simple, automated, pre-column OPA derivatization and reversed-phase HPLC method with the classical post-column OPA derivatization and ion-exchange HPLC procedure. A comparison of UV and fluorescent detection of the amino acid oligomers is also presented. The conclusion reached is that the pre-column OPA derivatization, reversed-phase HPLC and UV detection produces enhanced separation, improved sensitivity and faster analysis than post-column OPA derivatization, ion-exchange HPLC and fluorescence detection.

Chow, J.; Orenberg, J. B.; Nugent, K. D.

1987-01-01

385

Coal extraction  

SciTech Connect

Coal is extracted using a mixed solvent which includes a substantially aromatic component and a substantially naphthenic component, at a temperature of 400/sup 0/ to 500/sup 0/C. Although neither component is an especially good solvent for coal by itself, the use of mixed solvent gives greater flexibility to the process and offers efficiency gains.

Clarke, J.W.; Kimber, G.M.; Rantell, T.D.; Snape, C.E.

1985-06-04

386

[Determination of amino acids in Galli Gigerii endothelium corneum by HPLC with pre-column derivatization].  

PubMed

Hydrolytic amino acids were extracted by acid hydrolysis method, then derivatized with phenyl isothiocyanate (PITC). And the samples were analysed by HPLC on an Ultimate Prime C18 (4.6 mm x 250 mm, 5 microm) column with gradient elution of 0.1 mol x L(-1) sodium acetate buffer solution (adjusted to pH 6. 5)-acetonitrile (93:7) (A) and acetonitrile-water (8:2) (B) at a flow rate of 1.0 mL x min(-1). Column temperature was 40 degrees C and the detected wavelength was 254 nm. Amino acids derivative solution remained stable in 36 hours. The response was linear for 16 amino acids with a correlation coefficient r > 0.999 5. The average recoveries were 98.01% -101.8%. The method is reliable with good accuracy and repeatability, which is useful for the determination of amino acids in Galli Gigerii Endothelium Corneum. PMID:25039183

Liang, Kun; Zhang, Dan; Shi, Ji; Hu, Hong; Xiu, Yan-Feng; Jia, Tian-Zhu

2014-04-01

387

Column properties and flow profiles of a flat, wide column for high-pressure liquid chromatography  

SciTech Connect

The design and the construction of a pressurized, flat, wide column for high-performance liquid chromatography (HPLC) are described. This apparatus, which is derived from instruments that implement over-pressured thin layer chromatography, can carry out only uni-dimensional chromatographic separations. However, it is intended to be the first step in the development of more powerful instruments that will be able to carry out two-dimensional chromatographic separations, in which case, the first separation would be a space-based separation, LC{sup x}, taking place along one side of the bed and the second separation would be a time-based separation, LC{sup t}, as in classical HPLC but proceeding along the flat column, not along a tube. The apparatus described consists of a pressurization chamber made of a Plexiglas block and a column chamber made of stainless steel. These two chambers are separated by a thin Mylar membrane. The column chamber is a cavity which is filled with a thick layer (ca. 1 mm) of the stationary phase. Suitable solvent inlet and outlet ports are located on two opposite sides of the sorbent layer. The design allows the preparation of a homogenous sorbent layer suitable to be used as a chromatographic column, the achievement of effective seals of the stationary phase layer against the chamber edges, and the homogenous flow of the mobile phase along the chamber. The entire width of the sorbent layer area can be used to develop separations or elute samples. The reproducible performance of the apparatus is demonstrated by the chromatographic separations of different dyes. This instrument is essentially designed for testing detector arrays to be used in a two-dimensional LC{sup x} x LC{sup t} instrument. The further development of two-dimension separation chromatographs based on the apparatus described is sketched.

Mriziq, Khaled S [ORNL; Guiochon, Georges A [ORNL

2008-01-01

388

Heat Transfer Analysis for a Fixed CST Column  

SciTech Connect

In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, a transient two-dimensional heat transfer model that includes the conduction process neglecting the convection cooling mechanism inside the crystalline silicotitanate (CST) column has been constructed and heat transfer calculations made for the present design configurations. For this situation, a no process flow condition through the column was assumed as one of the reference conditions for the simulation of a loss-of-flow accident. A series of the modeling calculations has been performed using a computational heat transfer approach. Results for the baseline model indicate that transit times to reach 130 degrees Celsius maximum temperature of the CST-salt solution column are about 96 hours when the 20-in CST column with 300 Ci/liter heat generation source and 25 degrees Celsius initial column temperature is cooled by natural convection of external air as a primary heat transfer mechanism. The modeling results for the 28-in column equipped with water jacket systems on the external wall surface of the column and water coolant pipe at the center of the CST column demonstrate that the column loaded with 300 Ci/liter heat source can be maintained non-boiling indefinitely. Sensitivity calculations for several alternate column sizes, heat loads of the packed column, engineered cooling systems, and various ambient conditions at the exterior wall of the column have been performed under the reference conditions of the CST-salt solution to assess the impact of those parameters on the peak temperatures of the packed column for a given transient time. The results indicate that a water-coolant pipe at the center of the CST column filled with salt solution is the most effective one among the potential design parameters related to the thermal energy dissipation of decay heat load. It is noted that the cooling mechanism at the wall boundary of the column has significant impact on maximum and wall temperatures of the column. In addition, the results computed by the present model were verified by the theoretical results. The analysis results will provide quantitative information associated with the process heat control and management of the CST base design. For example, transient responses of the CST system under a loss-of-flow accident condition will provide safety design information for an emergency cooling system of the column.

Lee, S.Y.

2004-02-19

389

Digital pulse processing  

E-print Network

This thesis develops an exact approach for processing pulse signals from an integrate-and-fire system directly in the time-domain. Processing is deterministic and built from simple asynchronous finite-state machines that ...

McCormick, Martin (Martin Steven)

2012-01-01

390

Pulsed-neutron monochromator  

DOEpatents

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, H.A. Jr.

1984-01-01

391

Pulsed-neutron monochromator  

DOEpatents

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, Jr., Herbert A. (Oak Ridge, TN)

1985-01-01

392

Transport of sulfadiazine in soil columns — Experiments and modelling approaches  

NASA Astrophysics Data System (ADS)

Antibiotics, such as sulfadiazine, reach agricultural soils directly through manure of grazing livestock or indirectly through the spreading of manure or sewage sludge on the field. Knowledge about the fate of antibiotics in soils is crucial for assessing the environmental risk of these compounds, including possible transport to the groundwater. Transport of 14C-labelled sulfadiazine was investigated in disturbed soil columns at a constant flow rate of 0.26 cm h - 1 near saturation. Sulfadiazine was applied in different concentrations for either a short or a long pulse duration. Breakthrough curves of sulfadiazine and the non-reactive tracer chloride were measured. At the end of the leaching period the soil concentration profiles were determined. The peak maxima of the breakthrough curves were delayed by a factor of 2 to 5 compared to chloride and the decreasing limbs are characterized by an extended tailing. However, the maximum relative concentrations differed as well as the eluted mass fractions, ranging from 18 to 83% after 500 h of leaching. To identify relevant sorption processes, breakthrough curves of sulfadiazine were fitted with a convective-dispersive transport model, considering different sorption concepts with one, two and three sorption sites. Breakthrough curves can be fitted best with a three-site sorption model, which includes two reversible kinetic and one irreversible sorption site. However, the simulated soil concentration profiles did not match the observations for all of the used models. Despite this incomplete process description, the obtained results have implications for the transport behavior of sulfadiazine in the field. Its leaching may be enhanced if it is frequently applied at higher concentrations.

Wehrhan, Anne; Kasteel, Roy; Simunek, Jirka; Groeneweg, Joost; Vereecken, Harry

2007-01-01

393

Automated, fast and sensitive quantification of drugs in blood by liquid chromatography–mass spectrometry with on-line extraction: immunosuppressants  

Microsoft Academic Search

We developed a universal LC–mass spectrometry assay with automated online extraction (LC\\/LC–MS) to quantify the immunosuppressants cyclosporine, tacrolimus, sirolimus and SDZ-RAD alone or in combination in whole blood. After protein precipitation, samples were loaded on a C18 extraction column, were washed and, after activation of the column-switching valve, were backflushed onto the C8 analytical column. [M+Na]+ ions were detected in

Uwe Christians; Wolfgang Jacobsen; Natalie Serkova; Leslie Z. Benet; Christian Vidal; Karl-Fr. Sewing; Michael P. Manns; Gabriele I. Kirchner

2000-01-01

394

Pulsed spallation neutron sources  

SciTech Connect

This paper reviews the early history of pulsed spallation neutron source development ar Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provide a few examples of applications in fundamental condensed matter physics, materials science and technology.

Carpenter, J.M. [Argonne National Lab., IL (United States). Intense Pulsed Neutron Source Div.

1996-05-01

395

Micro pulse lidar  

Microsoft Academic Search

An eye safe, compact, solid-state lidar for profiling atmospheric cloud and aerosol scattering is described. The transmitter of the micro pulse lidar is a diode pumped microjoule pulse energy, high-repetition-rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver uses a photon counting solid-state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler.

J. D. Spinhirne

1993-01-01

396

Micro-column plasma emission liquid chromatograph  

DOEpatents

In a direct current plasma emission spectrometer for use in combination with a micro-column liquid chromatograph, an improved plasma source unit. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

Gay, Don D. (Aiken, SC)

1984-01-01

397

LED flicker pulsing  

NASA Astrophysics Data System (ADS)

There is need to replace hazardous radioluminescent light sources with a means of illumination that is environmentally friendly. This paper describes an electronic source that was developed as a potential candidate to replace low intensity tritium in a military system. It employs an LED for illumination and a 3-volt coin cell battery as a power source. This new light source is electronically invisible, requires minimal maintenance, and provides the lowest practical illumination to preclude detection by optical means. The low intensity requires that the LED be driven at DC current levels resulting in poor luminous efficiency. Therefore, in an effort to maximize battery life, the LED is pulsed into a more optically efficient mode of operation. However, conventional pulsing techniques are not employed because of concerns the electronics could be identified by conspicuous power spectral density (PSD) components in the electromagnetic spectrum generated by a pulsed LED. Therefore, flicker noise concepts have been employed to efficiently drive the LED while generating a virtually undetectable spectral signature. Although ideally the pulse durations, magnitudes, and spacings should be random, a significant reduction in conspicuous PSD components can be achieved when imposing practical constraints. The dominant components of the power spectrum are significantly reduced using fixed pulse durations and magnitudes while varying only the pulse spacing. The mean duty cycle is set to provide the same effective illumination as DC operation while generating a PSD normally associated with natural phenomena.

Johnson, Mark A.; Cote, Paul J.

2001-08-01

398

Method for determination of aflatoxin M? in cheese and butter by HPLC using an immunoaffinity column.  

PubMed

A rapid, sensitive convenient method for determination of aflatoxin M? (AFM?) in cheese and butter by HPLC was developed and validated. The method employs a safe extraction solution (mixture of acetonitrile, methanol and water) and an immunoaffinity column (IAC) for clean-up. Compared with the widely used method employing chloroform and a Florisil column, the IAC method has a short analytical time and there are no interference peaks. The limits of quantification (LOQ) of the IAC method were 0.12 and 0.14 µg/kg, while those of the Florisil column method were 0.47 and 0.23 µg/kg in cheese and buffer, respectively. The recovery and relative standard deviation (RSD) for cheese (spiked at 0.5 µg/kg) in the IAC method were 92% and 7%, respectively, while for the Florisil column method the corresponding values were 76% and 10%. The recovery and RSD for butter (spiked at 0.5 µg/kg) in the IAC method were 97% and 9%, and those in the Florisil method were 74% and 9%, respectively. In the IAC method, the values of in-house precision (n=2, day=5) of cheese and butter (spiked at 0.5 µg/kg) were 9% and 13%, respectively. The IAC method is superior to the Florisil column method in terms of safety, ease of handling, sensitivity and reliability. A survey of AFM? contamination in imported cheese and butter in Japan was conducted by the IAC method. AFM? was not detected in 60 samples of cheese and 30 samples of butter. PMID:21873812

Sakuma, Hisako; Kamata, Yoichi; Sugita-Konishi, Yoshiko; Kawakami, Hiroshi

2011-01-01

399

Signal to Noise Ratio Analysis of the Data from the Pulsed Airborne CO2 Lidar Measurements  

NASA Astrophysics Data System (ADS)

We are developing a differential absorption lidar (DIAL) for measuring the CO2 column concentrations from space for the ASCENDS mission. Our technique uses two pulsed laser transmitters to simultaneously measure the total column absorption by CO2 in 1570 nm band and O2 extinction in the Oxygen A-band by periodically stepping the laser wavelength at predetermined wavelengths across the absorption lines. The reflected laser signals from the surface and clouds are collected by the receiver telescope and detected by a set of single photon counting detectors. We used pulsed lasers and time resolved photon detection to distinguish the surface echoes from cloud and aerosol backscattering and to measure the column height. . The total column absorption at a given wavelength is determined from the ratio of the received laser pulse energy to the transmitted energy. The column gas concentrations and the spectral line shape are determined from curve fitting of the column absorptions as a function of the wavelength. We have built an airborne lidar to demonstrate the CO2 column measurement technique from the NASA Lear-25 aircraft. The airborne lidar scans the laser wavelength across the CO2 absorption line in 20 steps. The line scan rate is 450 Hz, the laser pulse energy is 25 uJ, and laser pulse widths are 1 usec. The backscatter photons are collected by a 20 cm telescope and detected by a near infrared photomultiplier tube. The detected photons are binned according to their arrival times with the use of a multichannel scaler. Several airborne measurements were conducted during October and December 2008, and August 2009 with many hours of CO2 column measurement data at the 1571.4, 1572.02 and 1572.33 nm CO2 absorption lines. The measurements were made over a variety of land and water surfaces and some through thin clouds. We also made several improvements to the instrument for the later flights. Measurements from early flights showed the receiver signal and noise levels were consistent with predictions And Cloud echoes could reliably be identified and separated from the surface echoes. Here we report a detailed assessment of the receiver signal to noise ratio from the airborne measurements , including those from recent flights. We will show samples of the received signal and noise from different altitudes and over types of ground surfaces. We will also determine the surface height variability and range measurement precisions from the time offlight of the laser pulses.

Sun, X.; Abshire, J. B.; Riris, H.; Allan, G. R.; Hasselbrack, W. E.

2009-12-01

400

Pulse oximetry: fundamentals and technology update.  

PubMed

Oxygen saturation in the arterial blood (SaO2) provides information on the adequacy of respiratory function. SaO2 can be assessed noninvasively by pulse oximetry, which is based on photoplethysmographic pulses in two wavelengths, generally in the red and infrared regions. The calibration of the measured photoplethysmographic signals is performed empirically for each type of commercial pulse-oximeter sensor, utilizing in vitro measurement of SaO2 in extracted arterial blood by means of co-oximetry. Due to the discrepancy between the measurement of SaO2 by pulse oximetry and the invasive technique, the former is denoted as SpO2. Manufacturers of pulse oximeters generally claim an accuracy of 2%, evaluated by the standard deviation (SD) of the differences between SpO2 and SaO2, measured simultaneously in healthy subjects. However, an SD of 2% reflects an expected error of 4% (two SDs) or more in 5% of the examinations, which is in accordance with an error of 3%-4%, reported in clinical studies. This level of accuracy is sufficient for the detection of a significant decline in respiratory function in patients, and pulse oximetry has been accepted as a reliable technique for that purpose. The accuracy of SpO2 measurement is insufficient in several situations, such as critically ill patients receiving supplemental oxygen, and can be hazardous if it leads to elevated values of oxygen partial pressure in blood. In particular, preterm newborns are vulnerable to retinopathy of prematurity induced by high oxygen concentration in the blood. The low accuracy of SpO2 measurement in critically ill patients and newborns can be attributed to the empirical calibration process, which is performed on healthy volunteers. Other limitations of pulse oximetry include the presence of dyshemoglobins, which has been addressed by multiwavelength pulse oximetry, as well as low perfusion and motion artifacts that are partially rectified by sophisticated algorithms and also by reflection pulse oximetry. PMID:25031547

Nitzan, Meir; Romem, Ayal; Koppel, Robert

2014-01-01

401

DNA Extraction  

NSDL National Science Digital Library

Teachers' Domain presents this interactive, adapted from the University of Nebraska's Plant and Soil Science eLibrary, with reading material and animations to help students learn the basics of DNA extraction. The lesson is divided into and introduction and the four processes involved: cell lysis, dismantling the cell membrane, removing unwanted cell parts, and precipitating the DNA. On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.

2010-10-07

402

Multihypothesis method in pulse deinterleaving  

Microsoft Academic Search

In the naval electronic environment, pulses emitted by radars are collected by electronic support measures receivers. The aim is to gather these pulses in such way that one cluster corresponds to one radar despite the waveform parameters agility. To achieve it, this paper describes a pulse train deinterleaving process using a multi-hypotheses architecture. A hypothesis tree, built from pulse measurements,

Cecile Brolly; Gerard Alengrin; Jean-Marc Lopez; Philippe F. Perez

1998-01-01

403

Pulse shaping with transmission lines  

DOEpatents

A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

Wilcox, R.B.

1985-08-15

404

Pulse shaping with transmission lines  

DOEpatents

A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

Wilcox, Russell B. (Oakland, CA)

1987-01-01

405

Design criteria for pultruded fiber-reinforced polymer composite columns  

Microsoft Academic Search

This dissertation investigated the behavior of pultruded fiber-reinforced polymer (FRP) composite columns under extensive time-independent short-term and time-dependent long-term experiments. Based on the experimental results, analytical studies were performed to propose a design approach for pultruded FRP composite columns. In the time-independent short-term tests, a total of 100 tests on wide flange, I-shape and box section columns were selected to

Yeol Choi

2000-01-01

406

Behavior of square concrete columns reinforced with Prefabricated Cage System  

Microsoft Academic Search

Behavior of normal strength concrete columns reinforced with a new reinforcement, termed Prefabricated Cage System (PCS) is\\u000a investigated. A total of 16 small-scale PCS and rebar reinforced column specimens were constructed and tested under monotonic\\u000a axial displacement. The experimental results indicate that the overall behavior of rebar and PCS reinforced specimens are\\u000a comparable prior to achieving the peak column load.

Mohammad ShamsaiHalil Sezen; Halil Sezen

2011-01-01

407

Energy savings in heat-integrated distillation columns  

Microsoft Academic Search

The heat-integrated distillation column (HIDiC) provides one of the most effective applications of heat-pump technologies to industrial processes. It reinforces a separation process and yields larger energy savings than other methods such as overhead-to-reboiler heat pumps, which involve moving heat between the hottest and coldest points in the distillation column. A simulation study of this column has been applied to

M. Nakaiwa; K. Huang; M. Owa; T. Akiya; T. Nakane; M. Sato; T. Takamatsu

1997-01-01

408

Monolithic silica columns for high-efficiency chromatographic separations  

Microsoft Academic Search

Studies on the structural and chromatographic properties of monolithic silica columns were reviewed. Monolithic silica columns prepared from tetraalkoxysilane by a sol–gel method showed high efficiency and high permeability on the basis of the small-sized silica skeletons, large-sized through-pores, and resulting through-pore size\\/skeleton size ratios much larger than those found in a particle-packed column.

Nobuo Tanaka; Hiroshi Kobayashi; Norio Ishizuka; Hiroyoshi Minakuchi; Kazuki Nakanishi; Ken Hosoya; Tohru Ikegami

2002-01-01

409

Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene  

Microsoft Academic Search

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting (14)C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence or residual PCE on column dispersivities. The

K. D. Pennell; M. Jin; L. M. Abriola; G. A. Pope

1994-01-01

410

View of a Water Column on the lead track towards ...  

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

View of a Water Column on the lead track towards the Roundhouse. A corner of the Boiler Shop is on the left, and behind the Column is the Carpenter Shop. The Water Column could swing over the track 90 degrees to line up with the Tender's Water Hatch - East Broad Top Railroad & Coal Company, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

411

View of a Water Column on the lead track towards ...  

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

View of a Water Column on the lead track towards the Roundhouse. A corner of the Boiler Shop is on the left, and behind the column is the Carpenter Shop. The Water Column could swing over the track 90 degrees to line up with the Tender's Water Hatch - East Broad Top Railroad & Coal Company, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

412

Self-heating of Pu-238 anion exchange column  

SciTech Connect

Heat and mass transfer calculations were performed to determine the effect of increases in the H-canyon Frames Waste Recovery (FWR) column loading on column temperatures during flow interruptions. The heat transfer calculations are based on a previous analysis of the H Frames columns, and the mass transfer calculations use data from two recent laboratory elutions. The current Technical Standard (TS) limits the total amount of Pu-238 on the column to 490 g. To meet production goals for NASA`s Cassini mission, this limit needs to be increased. In addition to the loading limit, the TS stipulates that column temperatures cannot exceed 60{degrees}C. Significant column heating occurs only when flow to the column is interrupted. During normal operation, column temperatures are approximately equal to the ambient temperature. Results from the laboratory elutions and the heat and mass transfer analyses show that, for an ambient temperature of 30{degrees}C, the maximum column temperature cannot reach the TS limit of 60{degrees}C until 80 min. after flow is interrupted during loading or washing or until 50 min. after flow is interrupted during elution. These times are independent of operating conditions. The heating rate for loading and washing was calculated assuming adiabatic heating at a maximum adsorbed plutonium concentration of 45 g/L. The heating rate for elution is based on adiabatic hearing at a total plutonium concentration of 71 g/L. The maximum total concentration during elution consists of 45 g/L adsorbed plutonium plus 26 g/L dissolved plutonium in equilibrium with the adsorbed solid. Based on the results of this study and the previous analysis of the H Frames columns, it is safe to raise the Pu-238 loading of the FWR column from 490 to 800 g or more without violating the TS column temperature limit of 60{degrees}C during a 15-min. flow interruption.

Laurinat, J.E.

1994-03-23

413

Extraction and purification of total RNA from Sreptococcus mutans biofilms  

Microsoft Academic Search

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 7W) with washing in phosphate-buffered

Jaime A. Cury; Hyun Koo

2007-01-01

414

Determination of the sedimentary microbial biomass by extractible lipid phosphate  

Microsoft Academic Search

The measurement of lipid phosphate is proposed as an indicator of microbial biomass in marine and estuarine sediments. This relatively simple assay can be performed on fresh, frozen or frozen-lyophilized sediment samples with chloroform methanol extraction and subsequent phosphate determination. The sedimentary lipid phosphate recovery correlates with the extractible ATP and the rate of DNA synthesis. Pulse-chase experiments show active

D. C. White; W. M. Davis; J. S. Nickels; J. D. King; R. J. Bobbie

1979-01-01

415

All-optical address extraction for optical routing  

Microsoft Academic Search

This paper describes the optical circuit that enables to extract address from a transmitted cell in an all-optical manner. Nonlinear optical loop mirrors (NOLM's) are used as all-optical switches in order to confirm the operation of the proposed circuit. The control pulses synchronized with address bits are generated from the transmitted cell. The address bits are successfully extracted without any

Ki-Hwan Park; Tetsuya Mizumoto; Akihiko Matsuura; Yoshiyuki Naito

1998-01-01

416

Stability of leaning column at Devils Tower National Monument, Wyoming  

USGS Publications Warehouse

In response to reports from climbers that an 8-meter section (referred to as the leaning column) of the most popular climbing route on Devils Tower in northeastern Wyoming is now moving when being climbed, scientists from the U.S. Geological Survey inspected the site to determine the stability of the column and the underlying column that serves as a support pedestal. Evidence of a recent tensile spalling failure was observed on the pedestal surface immediately beneath the contact with the overlying leaning column. The spalling of a flake-shaped piece of the pedestal, probably due to the high stress concentration exerted by the weight of the leaning column along a linear contact with the pedestal, is likely causing the present movement of the leaning column. Although it is unlikely that climbers will dislodge the leaning column by their weight alone, the possibility exists that additional spalling failures may occur from the pedestal surface and further reduce the stability of the leaning column and result in its toppling. To facilitate detection of further spalling failures from the pedestal, its surface has been coated with a layer of paint. Any new failures from the pedestal could result in the leaning column toppling onto the climbing route or onto the section of the Tower trail below.

Harp, Edwin L.; Lindsay, Charles R.

2006-01-01

417

Application of Z-contrast imaging to obtain column-by-column spectroscopic analysis of materials  

SciTech Connect

Z-contrast imaging has been shown to be an effective method for obtaining a high-resolution image from a scanning transmission electron microscope (STEM). The incoherent nature of the high-angle scattering makes image interpretation straightforward and intuitive with the resolution limited only by the 2.2 {Angstrom} electron probe. The optimum experimental conditions for Z-contrast imaging also coincide with those used for analytical microscopy, enabling microanalysis to be performed with the same spatial resolution as the image. The detection limits afforded by a parallel detection system for electron energy loss spectroscopy (EELS) allows column-by-column core-loss spectroscopy to be performed using the Z-contrast image to position the electron probe. Preliminary results from the study of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} illustrate the spatial resolution available with this technique and the potential applications for materials science.

Browning, N.D.; Pennycook, S.J.

1993-01-01

418

Determination of disulfoton in surface water samples by cloud-point extraction and gas chromatography  

Microsoft Academic Search

This article proposes an alternative method, using cloud-point extraction and gas chromatography, for extraction and determination of disulfoton in water samples. For cloud-point extraction, the nonionic surfactant Triton X-114 was used. Before gas chromatography, a cleanup stage for surfactant removal from the extracts was optimized. Cleanup used two columns, in series, containing silica gel and Florisil, with methanol:hexane (1?:?1) as

Anizio M. Faria; Raquel P. Dardengo; Claudio F. Lima; Antonio A. Neves; Maria Eliana L. R. Queiroz

2007-01-01

419

Environmental polychlorinated biphenyls: Acute toxicity of landfill soil extract to female prepubertal rats  

Microsoft Academic Search

Subsurface soil from a National Priorities List landfill containing about 2.5% polychlorinated biphenyls (PCBs) was extracted and the extract cleaned by Florisil® slurry and alumina column chromatography. The refined extract contained 48 mg\\/mL PCB, mainly trichlorobiphenyls and tetrachlorobiphenyls, traces of polychlorinated naphthalenes, 125 µg\\/mL 2,2-bis-p-chlorophenyl-1, 1-dichloroethylene (DDE), and low levels of chlorinated dibenzofurans. The refined extract was dissolved in corn

L. G. Hansen; M.-H. Li; A. Saeed; B. Bush

1995-01-01

420

Photoconductive circuit element pulse generator  

DOEpatents

A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.

Rauscher, Christen (Alexandria, VA)

1989-01-01

421

HydroPulse Drilling  

SciTech Connect

Tempress HydroPulse{trademark} tool increases overbalanced drilling rates by generating intense suction pulses at the drill bit. This report describes the operation of the tool; results of pressure drilling tests, wear tests and downhole drilling tests; and the business case for field applications. The HydroPulse{trademark} tool is designed to operate on weighted drilling mud at conventional flow rates and pressures. Pressure drilling tests confirm that the HydroPulse{trademark} tool provides 33% to 200% increased rate of penetration. Field tests demonstrated conventional rotary and mud motor drilling operations. The tool has been operated continuous for 50 hours on weighted mud in a wear test stand. This level of reliability is the threshold for commercial application. A seismic-while-drilling version of the tool was also developed and tested. This tool was used to demonstrate reverse vertical seismic profiling while drilling an inclined test well with a PDC bit. The primary applications for the HydroPulse{trademark} tool are deep onshore and offshore drilling where rate of penetration drives costs. The application of the seismic tool is vertical seismic profiling-while-drilling and look-ahead seismic imaging while drilling.

J.J. Kolle

2004-04-01

422

Differential extraction of axonally transported proteoglycans  

SciTech Connect

Axonally transported proteoglycans were differentially solubilized by a sequence of extractions designed to infer their relationship to nerve terminal membranes. Groups of goldfish were injected unilaterally with 35SO4 and contralateral optic tecta containing axonally transported molecules were removed 16 h later. Tecta were homogenized in isotonic buffer and centrifuged at 100,000 g for 60 min to create a total supernatant fraction. Subsequent homogenizations followed by recentrifugation were with hypotonic buffer (lysis extract), 1 M NaCl, Triton X-100 or alternatively Triton-1 M NaCl. Populations of proteoglycans in each extract were isolated on DEAE ion exchange columns and evaluated for content of glycosaminoglycans (GAGs). Results show the distribution of transported proteoglycans to be 26.3% total soluble, 13.7% lysis extract, 13.8% NaCl extract, 12.2% Triton extract, and 46.2% Triton-NaCl extract. Proteoglycans from all fractions contained heparan sulfate as the predominant GAG, with lesser amounts of chondroitin (4 or 6) sulfate. The possible localizations of transported proteoglycans suggested by the extraction results are discussed.

Elam, J.S. (Florida State Univ., Tallahassee (USA))

1990-10-01

423

An empirical computer model of the F-Area A-Line nitrogen oxides absorption column (F-8 Column)  

Microsoft Academic Search

Large quantities of oxides of nitrogen (NOâ) are routinely emitted from the F-Canyon dissolvers and from the F-Area A-Line denitrators. These gases are routed through a nitrogen oxides absorption column located in the A-Line. This column, referred to as the F-8 Column, removes NOâ from the offgas, streams of the dissolvers and denitrators and generates nitric acid. The nitric acid

K. L. Shanahan; S. F. Peterson

1989-01-01

424

Pulse delay and pulse compression of ultrashort light pulses in tight focusing  

NASA Astrophysics Data System (ADS)

The tight focusing of radially polarized ultrashort pulsed laser beam is investigated, based on the Richards-Wolf vector diffraction theory. It is found that pulse delay phenomenon occurs near the focus. This is, near the focus, the ultrashort light pulse slows down. Meanwhile, with the decrease of the velocity the ultrashort pulsed laser beam is compressed in propagation direction. The space compression in propagation direction indicates that, though the pulse duration of the ultrashort light pulse does not change, the spatial pulse length of the ultrashort light pulse is reduced due to the pulse delay phenomenon. It is also shown that the different numerical aperture of the objective exhibits different velocity of the pulse light.

Lin, Huichuan; Chen, Ziyang; Pu, Jixiong

2014-12-01

425

Increasing the RF energy per pulse of an RKO  

Microsoft Academic Search

The Air Force Research Laboratory RKO source has recently demonstrated the ability to convert electron beam power to RF power until the termination of the electron beam pulse, achieving a power of 1.5 GW at an energy of 170 J. These results represent an increase in power of 25-30% in power and energy extracted from this source. This paper discusses

K. J. Hendricks; M. D. Haworth; T. Englert; Don Shiffler; G. Baca; P. D. Coleman; L. Bowers; R. W. Lemke; Thomas A. Spencer; M. Joseph Arman

1998-01-01

426

Pulse shaping system  

DOEpatents

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

Skeldon, M.D.; Letzring, S.A.

1999-03-23

427

Pulse shaping system  

DOEpatents

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

Skeldon, Mark D. (Penfield, NY); Letzring, Samuel A. (Jemez Springs, NM)

1999-03-23

428

Pulse power linac  

DOEpatents

A linear acceleration for charged particles is constructed of a plurality of transmission line sections that extend between a power injection region and an accelerating region. Each line section is constructed of spaced plate-like conductors and is coupled to an accelerating gap located at the accelerating region. Each gap is formed between a pair of apertured electrodes, with all of the electrode apertures being aligned along a particle accelerating path. The accelerating gaps are arranged in series, and at the injection region the line sections are connected in parallel. At the injection region a power pulse is applied simultaneously to all line sections. The line sections are graduated in length so that the pulse reaches the gaps in a coordinated sequence whereby pulse energy is applied to particles as they reach each of the gaps along the accelerating path.

Villa, Francesco (Alameda, CA)

1990-01-01

429

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

PubMed Central

We report on the development and characterization of automated metal-free multiple-column nanoLC instrumentation for sensitive and high-throughput analysis of phosphopeptides with mass spectrometry analysis. The system implements a multiple-column capillary LC fluidic design developed for high-throughput analysis of peptides (Anal. Chem. 2001, 73, 3011–3021), incorporating modifications to achieve broad and sensitive analysis of phosphopeptides. The integrated nanoLC columns (50 µm i.d. × 30 cm containing 5 µm C18 particles) and the on-line solid phase extraction columns (150 µm i.d. × 4 cm containing 5 µm C18 particles) were connected to automatic switching valves with non-metal chromatographic accessories, and other modifications to avoid the exposure of the analyte to any metal surfaces during handling, separation, and electrospray ionization. The nanoLC developed provided a separation peak capacity of ?250 for phosphopeptides (and ?400 for normal peptides). A detection limit of 0.4 fmol was obtained when a linear ion trap tandem mass spectrometer (Finnegan LTQ) was coupled to a 50-µm i.d. column of the nanoLC. The separation power and sensitivity provided by the nanoLC-LTQ enabled identification of ?4600 phosphopeptide candidates from ?60 µg COS-7 cell tryptic digest followed by IMAC enrichment and ?520 tyrosine phosphopeptides from ?2 mg of human T cells digests followed by phosphotyrosine peptide immunoprecipitation. PMID:19217835

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

2009-01-01

430

Tunable THz pulse generation by optical rectification of ultrashort laser pulses with tilted pulse fronts  

Microsoft Academic Search

Optical rectification of ultrashort near-IR laser pulses with tilted pulse fronts and pulse energies of a few µJ in Mg-doped stoichiometric LiNbO 3 cooled to low temperature is a powerful technique for efficient generation of THz pulses. The pulse energy critically depends on the Mg doping (necessary for preventing photorefractive damage) and can be easily increased by a factor of

J. Hebling; A. G. Stepanov; G. Almási; B. Bartal; J. Kuhl

2004-01-01

431

Immunoaffinity column cleanup with liquid chromatography using post-column bromination for determination of aflatoxins in peanut butter, pistachio paste, fig paste, and paprika powder: collaborative study.  

PubMed

A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 and total aflatoxins at European regulatory limits. The test portion is extracted with methanol-water (8 + 2) for dried figs and paprika, and with methanol-water (8 + 2) plus hexane (or cyclohexane) for peanut butter and pistachios. The sample extract is filtered, diluted with phosphate buffer saline, and applied to an immunoaffinity column. The column is washed with water and the aflatoxins are eluted with methanol. Aflatoxins are quantitated by reversed-phase LC with post-column derivatization (PCD) involving bromination. PCD is achieved with either an electrochemical cell (Kobra cell) and addition of bromide to the mobile phase or pyridinium hydrobromide perbromide. Determination is by fluorescence. Peanut butter, pistachio paste, dried fig paste, and paprika powder samples, both naturally contaminated with aflatoxins and containing added aflatoxins, were sent to 16 collaborators in 16 European countries. Test portions of samples were spiked at levels of 2.4 and 9.6 ng/g for total aflatoxins which included 1.0 and 4.0 ng/g aflatoxin B1, respectively. Recoveries for total aflatoxins ranged from 71 to 92% with corresponding recoveries for aflatoxin B1 of 82 to 109%. Based on results for spiked samples (blind duplicates at 2 levels) as well as naturally contaminated samples (blind duplicates at 4 levels, including blank), the relative standard deviation for repeatability ranged from 4.6 to 23.3% for total aflatoxins and from 3.1 to 20.0% for aflatoxin B1. The relative standard deviation for reproducibility ranged from 14.1 to 34.2% for total aflatoxins, and from 9.1 to 32.2% for aflatoxin B1. The method showed acceptable within-laboratory and between-laboratory precision for all 4 matrixes, as evidenced by HORRAT values <1, at the low levels of determination for both total aflatoxins and aflatoxin B1. PMID:10772170

Stroka, J; Anklam, E; Jörissen, U; Gilbert, J

2000-01-01

432

Plasma heating by ultra-short laser pulses creates waveguides suitable for guiding  

NASA Astrophysics Data System (ADS)

Several important applications using ultra-short laser pulses require laser guiding over distances greater than the Rayleigh length. Nowadays the most promising guiding schemes are based on thermally driven laser-induced plasma expansion. Until now it was thought that laser pulses with 100s of ps were needed to heat the plasma through inverse Bremsstrahlung. Nevertheless ultra-short intense laser pulses can heat the plasma through the ionization mechanism allowing the generation of plasma channels. This work presents an experimental study using ˜60fs and ˜400fs laser pulses to characterize the time evolution of expanding plasma columns created with different gases. Simulations show that the dominant effect, which contributes for the initial plasma temperature for plasmas created by ultra-short laser pulses, is associated to the ionization process. Also circular polarized light can contribute for a higher initial plasma temperature.

Dias, J. M.; Lemos, Nuno; Berardo, J.; Lopes, N.; Figueira, G.; Fiuza, F.; Issac, R. C.; Jaroszynski, D. A.; Silva, L. O.

2011-11-01

433

Seismogenic frictional melting in the magmatic column  

NASA Astrophysics Data System (ADS)

Lava dome eruptions subjected to high extrusion rates commonly evolve from endogenous to exogenous growth and limits to their structural stability hold catastrophic potential as explosive eruption triggers. In the conduit, strain localisation in magma, accompanied by seismogenic failure, marks the onset of brittle magma ascent dynamics. The rock record of exogenous dome structures preserves vestiges of cataclastic processes (Cashman et al., 2008; Kennedy and Russell, 2011) and of thermal anomalies (Kendrick et al., 2012), key to unravelling subsurface processes. Here, a combined structural, thermal and magnetic investigation of a shear band crosscutting a large block erupted in 2010 at Soufrière Hills volcano (SHV) reveals evidence of faulting and frictional melting within the magmatic column. The mineralogy of this pseudotachylyte vein offers confirmation of complete recrystallisation with an isothermal remanent magnetisation signature that typifies local electric currents in faults. The pseudotachylyte presents an impermeable barrier, which is thought to have influenced the degassing pathway. Such melting events may be linked to the step-wise extrusion of magma accompanied by repetitive long-period (LP) drumbeat seismicity at SHV (Neuberg et al., 2006). Frictional melting of SHV andesite in a high velocity rotary shear apparatus highlights the small slip distances (< 15 cm) required to bring 800 °C magma to melting point at upper conduit stress conditions (10 MPa). We conclude that frictional melting is an inevitable consequence of seismogenic, conduit-dwelling magma fracture during dome building eruptions and that it may have an important influence on magma ascent dynamics.

Kendrick, J. E.; Lavallée, Y.; Hess, K.-U.; De Angelis, S.; Ferk, A.; Gaunt, H. E.; Dingwell, D. B.; Leonhardt, R.

2013-10-01

434

Detection of ketamine and its metabolites in human hair using an integrated nanoflow liquid chromatography column and electrospray emitter fritted with a single porous 10 ?m bead.  

PubMed

Targeting metabolites incorporated into hair following drug administration is useful for evidential purposes as this approach can aid in differentiating between administration and passive exposure. Greater analytical sensitivity is required than for targeting the parent drug alone. A 20 ?m i.d. fused silica capillary column with an integrated electrospray emitter fritted with a single porous 10 ?m polymeric bead has been successfully fabricated to facilitate this purpose. The sensitivity gains through the use of these integrated single fritted columns coupled to a nanoelectrospray source (nanoflow-LC nanoESI) over conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS) columns was explored by their application to the detection of ketamine and its phase I metabolites in human hair. Hair was collected from 4 volunteers following the administration of a small oral dose of ketamine (50 mg) and subsequently analysed by the capillary-LC nanoESI approach. The drug and its metabolites were extracted from hair using solid phase extraction following a methanolic wash, pulverisation with a ball mill and acid digestion. From a 50 ?L extract, 1 ?L was injected and the method provided a limit of detection estimated to be 5 fg on column for ketamine and norketamine and 10 fg for dehydronorketamine. The single porous frit minimises extra column band broadening and offers an alternative fritting approach which reduces the blocking of the electrospray emitter, in comparison with other approaches such as sintering and polymerisation. PMID:23332304

Parkin, Mark C; Longmoore, Alana M; Turfus, Sophie C; Braithwaite, Robin A; Cowan, David A; Elliott, Simon; Kicman, Andrew T

2013-02-15

435

Preliminary Study of High Resolution HPLC Analytical Method for Sedimentary Pigments Based on Coupled C8 Columns  

NASA Astrophysics Data System (ADS)

The pigments in marine water columns can provide accurate estimates of community composition and abundance of phytoplankton. In addition, the sedimentary pigments, especially the derivatives of chlorophyll such as pyrophaeophytins, pyrophaeophorbides and steryl chlorin esters (SCEs) formed during early diagenesis can also provide information on the primary producer community and the changes in paleoproductivity. Accordingly, analysis of pigments and their derivatives is of great importance for oceanography, limnology and geochemistry. Many methods have been developed for the separation of chlorophylls, carotenoids and their derivatives derived from phytoplankton and water column samples using high-performance liquid chromatography (HPLC). Methods widely cited in the literatures include those developed by Wright et al. (1991) and Zapata et al. (2000). Both methods use reversed-phase columns, but C18 column was employed in Wright et al. (1991) and C8 column in Zapata et al. (2000). However, evident coelutions are observed in published works. This will particularly cause problematic identification and quantification in dealing with sedimentary pigments which are highly complex and often display a broad range in polarity. Clearly, it is necessary to improve the separation of the complex pigments if the information carried by the pigments is to be used fully. Coupled C18 columns were used in the HPLC method developed by Airs et al. (2001) for the analysis of complex pigment distributions. Improved chromatographic resolution, more pigment components and novel bacteriochlorophyll derivatives were obtained by this method. It indicates a new road for HPLC method development. C8 column has shorter carbon chains than that of C18 column and can provide less retention of apolar compounds which is of particular advantaged to hydrophobic chlorophyll a, b and their derivatives. That is one of the reasons why the C8 method developed by Zapata et al. (2000) is admittedly better than C18 method when analyze phytoplankton and water samples. Here we present an improved HPLC method based on coupled C8 columns and the method of Zapata et al. (2000). The flow rate and elution gradient of Zapata et al. (2000) method was adjusted, and the pigment extracts of surface sediment from different sites such as the Yangtze River Estuary, North Yellow Sea and the Xiangxi River in Three Gorges Reservoir,China were analyzed using the novel method. More pigments identified, improved resolution and LCMS applicability reveal the potential of the coupled C8 columns method for analyzing c