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Sample records for chromatographic-ion trap tandem

  1. Performance characteristics of an automated gas chromatograph-ion trap mass spectrometer system used for the 1995 Southern Oxidants Study field investigation in Nashville, Tennessee

    NASA Astrophysics Data System (ADS)

    Daughtrey, E. Hunter; Adams, Jeffrey R.; Oliver, Karen D.; Kronmiller, Keith G.; McClenny, William A.

    1998-09-01

    A trailer-deployed automated gas chromatograph-mass spectrometer (autoGC-MS) system capable of making continuous hourly measurements was used to determine volatile organic compounds (VOCs) in ambient air at New Hendersonville, Tennessee, and Research Triangle Park, North Carolina, in 1995. The system configuration, including the autoGC-MS, trailer and transfer line, siting, and sampling plan and schedule, is described. The autoGC-MS system employs a pair of matched sorbent traps to allow simultaneous sampling and desorption. Desorption is followed by Stirling engine cryofocusing and subsequent GC separation and mass spectral identification and quantification. Quality control measurements described include evaluating precision and accuracy of replicate analyses of independently supplied audit and round-robin canisters and determining the completeness of the data sets taken in Tennessee. Data quality objectives for precision (±10%) and accuracy (±20%) of 10- to 20-ppbv audit canisters and a completeness of >75% data capture were met. Quality assurance measures used in reviewing the data set include retention time stability, calibration checks, frequency distribution checks, and checks of the mass spectra. Special procedures and tests were used to minimize sorbent trap artifacts, to verify the quality of a standard prepared in our laboratory, and to prove the integrity of the insulated, heated transfer line. A rigorous determination of total system blank concentration levels using humidified scientific air spiked with ozone allowed estimation of method detection limits, ranging from 0.01 to 1.0 ppb C, for most of the 100 target compounds, which were a composite list of the target compounds for the Photochemical Assessment Monitoring Station network, those for Environmental Protection Agency method TO-14, and selected oxygenated VOCs.

  2. Quantification of Biogenic and Anthropogenic Hydrocarbons using a Commercial Gas Chromatograph - Ion Trap Mass Spectrometer at a Ground Site near Fort McKay, AB

    NASA Astrophysics Data System (ADS)

    Tokarek, T. W.; Osthoff, H. D.

    2014-12-01

    The extraction of fossil fuels from the Alberta oil sands has been the focus of considerable attention due to its association with sizeable emissions of a variety of atmospheric pollutants, the magnitude and impacts of which are currently poorly constrained by observations. In order to more reliably estimate the magnitude and impact of these emissions, an intensive air quality measurement campaign, called "Fort McMurray Oil Sands Strategic Investigation of Local Sources" (FOSSILS), was conducted in the summer of 2013 as part of the Alberta-Canada joint oil sands monitoring program (JOSM) to identify and quantify emissions and their transformations from the Alberta oil sands. The challenge is that the region is surrounded by boreal forest, which provides a substantial background of biogenic hydrocarbons during summer. In this presentation, measurements of volatile organic compounds (VOCs) at the AMS13 ground site near Fort McKay, Alberta, from Aug 17 to Sept 6, 2013 using a commercial Griffin 450 gas chromatograph equipped with ion trap mass spectrometric detection and Tenax preconcentration are described. The combination of retention information and electron impact mass spectral data allowed unambiguous identification and quantification of the major biogenic monoterpenes, e.g., α and β-pinene, limonene, camphene, and 3Δ-carene, and of many anthropogenically derived hydrocarbons. Mixing ratios of biogenic hydrocarbons varied with time of day, temperature, and solar radiation, with maxima typically occurring at night, rationalized by nocturnal mixing heights and low mixing ratios of the nocturnal oxidants ozone (O3) and the nitrate radical (NO3). In contrast, mixing ratios of anthropogenic VOCs, e.g., benzene, toluene, ethyl benzene, and o-, p-, and m-xylene (BTEX), strongly depended on meteorological conditions, i.e., local wind direction. During episodes with high BTEX abundance, many additional high molecular weight hydrocarbons were observed which were not

  3. Trapped Particle Instability in Kinetic Stabilized Tandem Mirror

    NASA Astrophysics Data System (ADS)

    Berk, Herbert; Pratt, Jane

    2009-11-01

    The kinetic stabilizer tandem mirror (KSTM) devised by R. F. Post (J. Fus. Energy 2007) is an innovative concept devised to stabilize a symmetric tandem mirror machines using a concept devised by D. Ryutov (Proc. of Course and Workshop, Varenna, Italy, 1987) and empirically verified in the Gas Dynamic Trap (Ivanov, et. al. Trans. Fusion Technology 39, 127, 2001). The KSTM uses the momentum flux of unconfined particles that only sample the outer end regions of the mirror where there is very favorable field line curvature. Charged ion beams at relatively low energy are externally injected into the ends and reflected out from the ends. MHD stability with a power drain less than the fusion power production can be achieved. We examine the effect of fast growing trapped particle instability (Berk et. al. Sov J. Plasma Phys. 1983) on the overall stability. In this case stability is very sensitive to the electron connection between the stabilizer and end plug.

  4. Trapped Particle Instabilities in the Kinetically Stabilized Tandem Mirror

    NASA Astrophysics Data System (ADS)

    Pratt, J.; Berk, H. L.; Horton, W.

    2009-05-01

    The kinetically stabilized tandem mirror (KSTM) is an innovative design to stabilize MHD modes in an axially symmetric tandem mirror machine (Post, J. Fus. Energy 2007). Originally proposed by Ryutov (Ryutov, Proc. of Course and Workshop, Varenna, Italy, 1987), this stabilizer has been empirically verified in the Gas Dynamic Trap (Ivanov, Anakeev et.al. Trans. Fusion Technology. 39, 127, 2001). The KSTM uses the momentum flux of escaping particles that sample good magnetic-field-line-curvature region outside the central confinement region. Charged ion beams at relatively low energy are externally injected from the ends into the expander region at an energy that is consistent with a stable MHD prediction and acceptable power loss for fusion. If stable, the KSTM would be extremely useful for limiting radial diffusion since the chaotic step size is minimized. We confirm that MHD stability is achieved in the KSTM. We examine the effect of the trapped particle instability discussed in Berk, Rosenbluth, et al. Sov. J. Plasma Phys. 1983 on overall stability. In this case stability is very sensitive to the electron connection between the stabilizer and the end plug.

  5. Tandem-in-space and tandem-in-time mass spectrometry: Triple quadrupoles and quadrupole ion traps

    SciTech Connect

    Johnson, J.V.; Yost, R.A. ); Kelley, P.E.; Bradford, D.C. )

    1990-10-15

    Tandem-in-time and tandem-in-space MS/MS on quadrupole ion trap (ITMS) and triple quadrupole (TQMS) tandem mass spectrometers, respectively, were compared by evaluating the MS/MS daughter spectra, efficiencies of collision-induced dissociation (CID), limits of detection, and dynamic ranges obtained for the methane positive chemical ionization (PCI)-CID of two alkylphosphonates. Although the yield of daughter ions is dependent upon a number of instrumental parameters on both instruments, with judicious selection of parameters the ITMS and TQMS both yielded daughter ions of similar relative abundances. The ITMS had greater efficiencies of fragmentation, collection, and mass selection and transmission of the daughter ions to the detector. With PCI-MS/MS analysis of diisopropyl methylphosphonate standards introduced via capillary gas chromatography, full daughter spectra could be obtained for as little as 15 pg and 1.5 ng injected for the ITMS and the TQMS, respectively.

  6. ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS BY ION TRAP TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    An ion-trap mass spectrometer with a wave board and tandem mass spectrometry software was used to analyze gas chromatographically separated polycyclic aromatic hydrocarbons (PAHs) by using collision-induced dissociation (CID). The nonresonant (multiple collision) mode was used to...

  7. Production of Ar{sup q+} ions with a tandem linear Paul trap

    SciTech Connect

    Higaki, H. Nagayasu, K.; Iwai, T.; Ito, K.; Okamoto, H.

    2015-06-29

    A tandem linear Paul trap was used to create highly charged Argon ions by electron impact ionizations. By improving the operation scheme, the production of Ar{sup 4+} ions was confirmed. Possible improvements for the future experiments with laser cooled Ca{sup +} ions are suggested.

  8. Hybrid dielectric light trapping designs for thin-film CdZnTe/Si tandem cells.

    PubMed

    Chung, H; Zhou, C; Tee, X T; Jung, K-Y; Bermel, P

    2016-07-11

    Tandem solar cells consisting of high bandgap cadmium telluride alloys atop crystalline silicon have potential for high efficiencies exceeding the Shockley-Queisser limit. However, experimental results have fallen well below this goal significantly because of non-ideal current matching and light trapping. In this work, we simulate cadmium zinc telluride (CZT) and crystalline silicon (c-Si) tandems as an exemplary system to show the role that a hybrid light trapping and bandgap engineering approach can play in improving performance and lowering materials costs for tandem solar cells incorporating crystalline silicon. This work consists of two steps. First, we optimize absorption in the crystalline silicon layer with front pyramidal texturing and asymmetric dielectric back gratings, which results in 121% absorption enhancement from a planar structure. Then, using this pre-optimized light trapping scheme, we model the dispersion of the CdxZn1-xTe alloys, and then adjust the bandgap to realize the best current matching for a range of CZT thicknesses. Using experimental parameters, the corresponding maximum efficiency is predicted to be 16.08 % for a total tandem cell thickness of only 2.2 μm. PMID:27410890

  9. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    NASA Astrophysics Data System (ADS)

    Li, Guijun; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing

    2014-06-01

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400-800 nm) and bottom (800-1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  10. Pyramidal surface textures for light trapping and antireflection in perovskite-on-silicon tandem solar cells.

    PubMed

    Schneider, Bennett W; Lal, Niraj N; Baker-Finch, Simeon; White, Thomas P

    2014-10-20

    Perovskite-on-silicon tandem solar cells show potential to reach > 30% conversion efficiency, but require careful optical control. We introduce here an effective light-management scheme based on the established pyramidal texturing of crystalline silicon cells. Calculations show that conformal deposition of a thin film perovskite solar cell directly onto the textured front surface of a high efficiency silicon cell can yield front surface reflection losses as low as 0.52mA/cm(2). Combining this with a wavelength-selective intermediate reflector between the cells additionally provides effective light-trapping in the high-bandgap top cell, resulting in calculated absolute efficiency gains of 2 - 4%. This approach provides a practical and effective method to adapt existing high efficiency silicon cell designs for use in tandem cells, with conversion efficiencies approaching 35%. PMID:25607299

  11. Development of a Tandem Electrodynamic Trap Apparatus for Merging Charged Droplets and Spectroscopic Characterization of Resultant Dried Particles.

    PubMed

    Kohno, Jun-Ya; Higashiura, Tetsu; Eguchi, Takaaki; Miura, Shumpei; Ogawa, Masato

    2016-08-11

    Materials work in multicomponent forms. A wide range of compositions must be tested to obtain the optimum composition for a specific application. We propose optimization using a series of small levitated single particles. We describe a tandem-trap apparatus for merging liquid droplets and analyzing the merged droplets and/or dried particles that are produced from the merged droplets under levitation conditions. Droplet merging was confirmed by Raman spectroscopic studies of the levitated particles. The tandem-trap apparatus enables the synthesis of a particle and spectroscopic investigation of its properties. This provides a basis for future investigation of the properties of levitated single particles. PMID:27438227

  12. ANALYSIS FOR B-LACTAM ANTIBIOTICS IN KIDNEY TISSUE BY LIQUID CHROMATOGRAPHY WITH ELECTROSPRAY IONIZATION AND SELECTIVE REACTION MONITORING/TANDEM ION TRAP MASS SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eleven B-lactams antibiotics were analyzed in fortified and incurred beef kidney tissue using high-performance liquid chromatography/selective reaction monitoring/tandem ion trap mass spectrometry. The analytes included: deacetylcephapirin, amoxicillin, cephapirin, desfuroylceftiofur cysteine disul...

  13. Time domain simulation of tandem silicon solar cells with optimal textured light trapping enabled by the quadratic complex rational function.

    PubMed

    Chung, H; Jung, K-Y; Tee, X T; Bermel, P

    2014-05-01

    Amorphous silicon/crystalline silicon (a-Si/c-Si) micromorph tandem cells, with best confirmed efficiency of 12.3%, have yet to fully approach their theoretical performance limits. In this work, we consider a strategy for improving the light trapping and charge collection of a-Si/c-Si micromorph tandem cells using random texturing with adjustable short-range correlations and long-range periodicity. In order to consider the full-spectrum absorption of a-Si and c-Si, a novel dispersion model known as a quadratic complex rational function (QCRF) is applied to photovoltaic materials (e.g., a-Si, c-Si and silver). It has the advantage of accurately modeling experimental semiconductor dielectric values over the entire relevant solar bandwidth from 300-1000 nm in a single simulation. This wide-band dispersion model is then used to model a silicon tandem cell stack (ITO/a-Si:H/c-Si:H/silver), as two parameters are varied: maximum texturing height h and correlation parameter f. Even without any other light trapping methods, our front texturing method demonstrates 12.37% stabilized cell efficiency and 12.79 mA/cm² in a 2 μm-thick active layer. PMID:24922389

  14. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping

    PubMed Central

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-01-01

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs. PMID:26566176

  15. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping.

    PubMed

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-01-01

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs. PMID:26566176

  16. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping

    NASA Astrophysics Data System (ADS)

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-11-01

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs.

  17. Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

    NASA Astrophysics Data System (ADS)

    Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-06-01

    A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

  18. Accurate mass determination of short-lived isotopes by a tandem Penning-trap mass spectrometer

    SciTech Connect

    Stolzenberg, H.; Becker, S.; Bollen, G.; Kern, F.; Kluge, H.; Otto, T.; Savard, G.; Schweikhard, L. ); Audi, G. ); Moore, R.B. ); The ISOLDE Collaboration

    1990-12-17

    A mass spectrometer consisting of two Penning traps has been set up for short-lived isotopes at the on-line mass separator ISOLDE at CERN. The ion beam is collected and cooled in the first trap. After delivery to the second trap, high-accuracy direct mass measurements are made by determining the cyclotron frequency of the stored ions. Measurements have been performed for {sup 118}Cs--{sup 137}Cs. A resolving power of over 10{sup 6} and an accuracy of 1.4{times}10{sup {minus}7} have been achieved, corresponding to about 20 keV.

  19. Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

    NASA Astrophysics Data System (ADS)

    Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-05-01

    A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  20. Identification of cephapirin metabolites and degradants in bovine milk by electrospray ionization--ion trap tandem mass spectrometry.

    PubMed

    Heller, D N; Kaplan, D A; Rummel, N G; von Bredow, J

    2000-12-01

    Liquid chromatography-ion trap tandem mass spectrometry (LC-MS/MS) with electrospray ionization was used to identify cephapirin metabolites and degradants in milk from cows dosed with cephapirin. The milk was extracted according to a previously published procedure. Structures for various components were tentatively identified by their molecular weight, product ion mass spectra, and/or correspondence to standard mass spectra. These components may have occurred as metabolites or as degradants that occurred on storage or during extraction. Compounds identified in the milk included cephapirin, desacetylcephapirin, cephapirin lactone, hydrolyzed cephapirin, and a reduced cephapirin lactone that has not previously been reported. Methylcephapirin was also identified, possibly as a trace contaminant in the formulation. Analysis of incurred milk extracts showed that cephapirin and desacetylcephapirin are the major residues in milk. Desacetylcephapirin residues persisted about as long as the parent drug. The detection limit for both residues by LC-MS/MS was approximately 1 ng/mL in milk. These results have implications for microbiological methods or rapid test kits, if such methods or kits respond to cephapirin metabolites and degradants present in the milk. PMID:11141270

  1. Gas chromatography-ion trap tandem mass spectrometry method for the analysis of methoxylated polybrominated diphenyl ethers in fish.

    PubMed

    Losada, S; Santos, F J; Covaci, A; Galceran, M T

    2010-08-01

    Gas chromatography coupled to ion trap tandem mass spectrometry (GC-ITMS-MS) is proposed for the analysis of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in fish and shellfish. MS-MS operating parameters related to the isolation and fragmentation of the precursor ions were optimized to achieve maximum sensitivity and selectivity. This new method allows the determination of both MeO-PBDEs and PBDEs in a single run. Low limits of detection (0.4-2.5 pg injected) and high precision (RSD<13%) were achieved. A sample treatment based on a selective pressurized liquid extraction (PLE) using Florisil as fat retainer was applied for the analysis of these compounds in fish samples. Method limits of quantification ranged from 0.11 to 0.95 ng g(-1) lipid weight for MeO-PBDEs and between 0.18 and 0.50 ng g(-1) lipid weight for PBDEs. In addition, good repeatability of the whole method was achieved (RSD<15%). The suitability of the method was evaluated by analyzing a certified reference material (SRM 1945, whale blubber) with satisfactory results. The developed method was applied to the simultaneous analysis of MeO-PBDEs and PBDEs in fish and shellfish samples from the Mediterranean Sea. PMID:20615508

  2. Improved 6-Plex Tandem Mass Tags Quantification Throughput Using a Linear Ion Trap-High-Energy Collision Induced Dissociation MS(3) Scan.

    PubMed

    Liu, Jane M; Sweredoski, Michael J; Hess, Sonja

    2016-08-01

    The use of tandem mass tags (TMT) as an isobaric labeling strategy is a powerful method for quantitative proteomics, yet its accuracy has traditionally suffered from interference. This interference can be largely overcome by selecting MS(2) fragment precursor ions for high-energy collision induced dissociation (HCD) MS(3) analysis in an Orbitrap scan. While this approach minimizes the interference effect, sensitivity suffers due to the high AGC targets and long acquisition times associated with MS(3) Orbitrap detection. We investigated whether acquiring the MS(3) scan in a linear ion trap with its lower AGC target would increase overall quantification levels with a minimal effect on precision and accuracy. Trypsin-digested proteins from Saccharomyces cerevisiae were tagged with 6-plex TMT reagents. The sample was subjected to replicate analyses using either the Orbitrap or the linear ion trap for the HCD MS(3) scan. HCD MS(3) detection in the linear ion trap vs Orbitrap increased protein identification by 66% with minor loss in precision and accuracy. Thus, the use of a linear ion trap-HCD MS(3) scan during a 6-plex TMT experiment can improve overall identification levels while maintaining the power of multiplexed quantitative analysis. PMID:27377715

  3. Mass Spectrometry Parameters Optimization for the 46 Multiclass Pesticides Determination in Strawberries with Gas Chromatography Ion-Trap Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Fernandes, Virgínia C.; Vera, Jose L.; Domingues, Valentina F.; Silva, Luís M. S.; Mateus, Nuno; Delerue-Matos, Cristina

    2012-12-01

    Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET), maximum excitation energy or " q" value (q), and isolation mass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit. Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

  4. Differentiation of regioisomeric aromatic ketocarboxylic acids by atmospheric pressure chemical ionization CAD tandem mass spectrometry in a linear quadrupole ion trap mass spectrometer

    SciTech Connect

    Amundson, Lucas M.; Owen, Ben C.; Gallardo, Vanessa A.; Habicht, S. C.; Fu, M.; Shea, R. C.; Mossman, A. B.; Kenttämaa, Hilkka I.

    2011-01-01

    Positive-mode atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS n ) was tested for the differentiation of regioisomeric aromatic ketocarboxylic acids. Each analyte forms exclusively an abundant protonated molecule upon ionization via positive-mode APCI in a commercial linear quadrupole ion trap (LQIT) mass spectrometer. Energy-resolved collision-activated dissociation (CAD) experiments carried out on the protonated analytes revealed fragmentation patterns that varied based on the location of the functional groups. Unambiguous differentiation between the regioisomers was achieved in each case by observing different fragmentation patterns, different relative abundances of ion-molecule reaction products, or different relative abundances of fragment ions formed at different collision energies. The mechanisms of some of the reactions were examined by H/D exchange reactions and molecular orbital calculations.

  5. Differentiation of Regioisomeric Aromatic Ketocarboxylic Acids by Positive Mode Atmospheric Pressure Chemical Ionization Collision-Activated Dissociation Tandem Mass Spectrometry in a Linear Quadrupole Ion Trap Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Amundson, Lucas M.; Owen, Benjamin C.; Gallardo, Vanessa A.; Habicht, Steven C.; Fu, Mingkun; Shea, Ryan C.; Mossman, Allen B.; Kenttämaa, Hilkka I.

    2011-04-01

    Positive-mode atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS n ) was tested for the differentiation of regioisomeric aromatic ketocarboxylic acids. Each analyte forms exclusively an abundant protonated molecule upon ionization via positive-mode APCI in a commercial linear quadrupole ion trap (LQIT) mass spectrometer. Energy-resolved collision-activated dissociation (CAD) experiments carried out on the protonated analytes revealed fragmentation patterns that varied based on the location of the functional groups. Unambiguous differentiation between the regioisomers was achieved in each case by observing different fragmentation patterns, different relative abundances of ion-molecule reaction products, or different relative abundances of fragment ions formed at different collision energies. The mechanisms of some of the reactions were examined by H/D exchange reactions and molecular orbital calculations.

  6. Separation and Identification of Isomeric Glycans by Selected Accumulation-Trapped Ion Mobility Spectrometry-Electron Activated Dissociation Tandem Mass Spectrometry.

    PubMed

    Pu, Yi; Ridgeway, Mark E; Glaskin, Rebecca S; Park, Melvin A; Costello, Catherine E; Lin, Cheng

    2016-04-01

    One of the major challenges in structural characterization of oligosaccharides is the presence of many structural isomers in most naturally occurring glycan mixtures. Although ion mobility spectrometry (IMS) has shown great promise in glycan isomer separation, conventional IMS separation occurs on the millisecond time scale, largely restricting its implementation to fast time-of-flight (TOF) analyzers which often lack the capability to perform electron activated dissociation (ExD) tandem MS analysis and the resolving power needed to resolve isobaric fragments. The recent development of trapped ion mobility spectrometry (TIMS) provides a promising new tool that offers high mobility resolution and compatibility with high-performance Fourier transform ion cyclotron resonance (FTICR) mass spectrometers when operated under the selected accumulation-TIMS (SA-TIMS) mode. Here, we present our initial results on the application of SA-TIMS-ExD-FTICR MS to the separation and identification of glycan linkage isomers. PMID:26959868

  7. Rapid and sensitive gas chromatography-ion-trap tandem mass spectrometry method for the determination of tobacco-specific N-nitrosamines in secondhand smoke.

    PubMed

    Sleiman, Mohamad; Maddalena, Randy L; Gundel, Lara A; Destaillats, Hugo

    2009-11-01

    Tobacco-specific nitrosamines (TSNAs) are some of the most potent carcinogens in tobacco and cigarette smoke. Accurate quantification of these chemicals is needed to help assess public health risks. We developed and validated a specific and sensitive method to measure four TSNAs adsorbed to model surfaces and secondhand smoke (SHS) particles using gas chromatography-ion-trap tandem mass spectrometry. In an 18-m(3) room-sized chamber, a smoking machine generated realistic concentrations of SHS that were actively sampled on Teflon-coated fiber glass (TCFG) filters, and passively sampled on cellulose substrates. A simple solid-liquid extraction protocol using methanol as solvent was successfully applied to both substrates with recoveries ranging from 85 to 115%. For each TSNA, tandem MS parameters were optimized and the major fragmentation pathways were elucidated. The method showed excellent performance, with a linear dynamic range from 2 to 1000ngmL(-1), low detection limits (S/N>3) of 30-300pgmL(-1) and precision with experimental errors below 10% for all compounds. Moreover, no interfering peaks were observed, indicating a high selectivity of MS/MS without the need for a sample clean-up step. This method provides a suitable analytical tool to detect and quantify traces of TSNA in indoor environments polluted with SHS. PMID:19800070

  8. The trade-off of light trapping between top and bottom cell in micromorph tandem solar cells with sputtering ZnO:Al glass substrate

    NASA Astrophysics Data System (ADS)

    Bai, Lisha; Liu, Bofei; Fan, Jun; Zhang, Dekun; Wei, Changchun; Sun, Jian; Zhao, Ying; Zhang, Xiaodan

    2014-11-01

    A simulated and experimental investigation of the trade-off between light trapping and current matching in p-i-n structured a-Si:H/μc-Si:H tandem solar cells is presented, which aims to address the limited short circuit current density (Jsc) that results from the low long-wavelength light scattering of the fluorine-doped tin oxide (SnO2:F) substrates typically used. To this end, the mismatch of the Jsc between the top and bottom cells is reduced by utilizing a ZnO:Al substrate with optimized long-wavelength light scattering properties as the front contact, thereby improving the response of the bottom cell at the expense of the lower top cell's Jsc yet. A trade-off between the top and bottom cell's light response is subsequently found with SnO2 or ZnO:Al as a substrate, by introducing an n-type μc-SiOx intermediate reflector (IR) between the two component cells. An initial efficiency based on an approximate current matching of 11.90% is achieved for a-Si:H/μc-Si:H tandem solar cell by adopting a magnetron-sputtered and texture-etched ZnO:Al substrate and an optimized n-type μc-SiOx IR.

  9. A selective and sensitive method for quantitation of lysergic acid diethylamide (LSD) in whole blood by gas chromatography-ion trap tandem mass spectrometry.

    PubMed

    Libong, Danielle; Bouchonnet, Stéphane; Ricordel, Ivan

    2003-01-01

    A gas chromatography-ion trap tandem mass spectrometry (GC-ion trap MS-MS) method for detection and quantitation of LSD in whole blood is presented. The sample preparation process, including a solid-phase extraction step with Bond Elut cartridges, was performed with 2 mL of whole blood. Eight microliters of the purified extract was injected with a cold on-column injection method. Positive chemical ionization was performed using acetonitrile as reagent gas; LSD was detected in the MS-MS mode. The chromatograms obtained from blood extracts showed the great selectivity of the method. GC-MS quantitation was performed using lysergic acid methylpropylamide as the internal standard. The response of the MS was linear for concentrations ranging from 0.02 ng/mL (detection threshold) to 10.0 ng/mL. Several parameters such as the choice of the capillary column, the choice of the internal standard and that of the ionization mode (positive CI vs. EI) were rationalized. Decomposition pathways under both ionization modes were studied. Within-day and between-day stability were evaluated. PMID:12587679

  10. On-line capillary electrophoresis/microelectrospray ionization-tandem mass spectrometry using an ion trap storage/time-of-flight mass spectrometer with SWIFT technology.

    PubMed

    Jin, X; Kim, J; Parus, S; Lubman, D M; Zand, R

    1999-08-15

    The development of a system capable of the speed required for on-line capillary electrophoresis-tandem mass spectrometry (CE-MS/MS) of tryptic digests is described. The ion trap storage/reflectron time-of-flight (IT/reTOF) mass spectrometer is used as a nonscanning detector for rapid CE separation, where the peptides are ionized on-line using electrospray ionization (ESI). The ESI produced ions are stored in the ion trap and dc pulse injected into the reTOF-MS at a rate sufficient to maintain the separation achieved by CE. Using methodology generated by software and hardware developed in our lab, we can produce SWIFT (Stored Waveform Inverse Fourier Transform) ion isolation and TICKLE activation/fragmentation voltage waveforms to generate MS/MS at a rate as high as 10 Hz so that the MS/MS spectra can be optimized on even a 1-2 s eluting peak. In CE separations performed on tryptic digests of dogfish myelin basic protein (MBP) where eluting peaks 4-8 s wide are observed, it is demonstrated that an acquisition rate of 4 Hz provides > 20 spectra/peak and is more than sufficient to provide optimized MS/MS spectra of each of the eluting peaks in the electropherogram. The detailed structural analysis of dogfish MBP including several posttranslational modifications using CE-MS and CE-MS/MS is demonstrated using this method with < 10 fmol of material consumed. PMID:10464485

  11. Isolation of ubiquitinated substrates by tandem affinity purification of E3 ligase-polyubiquitin-binding domain fusions (ligase traps).

    PubMed

    Mark, Kevin G; Loveless, Theresa B; Toczyski, David P

    2016-02-01

    Ubiquitination is an essential protein modification that influences eukaryotic processes ranging from substrate degradation to nonproteolytic pathway alterations, including DNA repair and endocytosis. Previous attempts to analyze substrates via physical association with their respective ubiquitin ligases have had some success. However, because of the transient nature of enzyme-substrate interactions and rapid protein degradation, detection of substrates remains a challenge. Ligase trapping is an affinity purification approach in which ubiquitin ligases are fused to a polyubiquitin-binding domain, which allows the isolation of ubiquitinated substrates. Immunoprecipitation is first used to enrich for proteins that are bound to the ligase trap. Subsequently, affinity purification is used under denaturing conditions to capture proteins conjugated with hexahistidine-tagged ubiquitin. By using this protocol, ubiquitinated substrates that are specific for a given ligase can be isolated for mass spectrometry or western blot analysis. After cells have been collected, the described protocol can be completed in 2-3 d. PMID:26766115

  12. Liquid chromatography tandem mass spectrometric quantitation of sulfamethazine and its metabolites: direct analysis of swine urine by triple quadrupole and by ion trap mass spectrometry.

    PubMed

    Bartolucci, G; Pieraccini, G; Villanelli, F; Moneti, G; Triolo, A

    2000-01-01

    This work describes a new method for the quantitation of trace amounts of sulfamethazine (SMZ) and its main metabolite, N4-acetylsulfamethazine (Ac-SMZ), in swine urine, using high-performance liquid chromatography (HPLC) tandem mass spectrometric analysis of crude urine after addition of internal standard and simple dilution with water. The aim was to determine whether residues of this sulfamidic drug, normally administered to swine in order to prevent infectious diseases, were present in urine at levels lower than those permitted by regulatory authorities before human consumption (EU Project SMT, contract number CT 96-2092). A 10 microL volume of diluted urine was injected into a very short, narrow-bore chromatographic column (Zorbax SB-C18 2.1 i. d. x30 mm length, 3.5 microm pore size). Elution of the analytes of interest was achieved in less than seven minutes using a rapid gradient (from 20 to 80% methanol in 3 minutes). Either a PE Sciex API 365 triple quadrupole (QqQ), operated in the selected reaction monitoring (SRM) mode, or a Finnigan LCQ ion trap (IT) mass spectrometer, operated in narrow-range product ion scan, was used as the final detector. Electrospray (ESI) was used as the ionization technique. A comparison of the two tandem mass spectrometers was performed by analyzing the same set of test samples, at three concentration levels, on three different days. Linearity of responses of the calibration standards, intra- and inter-assay precision of the samples, specificity and limits of detection were evaluated for both systems. Both the QqQ and the IT instrument was suitable for rapid, sensitive and specific determination of the analytes, although the overall performance of the QqQ was slightly superior in terms of linearity, precision and sensitivity. PMID:10844733

  13. Tandem photonic-crystal thin films surpassing Lambertian light-trapping limit over broad bandwidth and angular range

    SciTech Connect

    Oskooi, Ardavan Tanaka, Yoshinori; Noda, Susumu

    2014-03-03

    Random surface texturing of an optically thick film to increase the path length of scattered light rays, first proposed nearly thirty years ago, has thus far remained the most effective approach for photon absorption over the widest set of conditions. Here, using recent advances in computational electrodynamics, we describe a general strategy for the design of a silicon thin film applicable to photovoltaic cells based on a quasi-resonant approach to light trapping where two partially disordered photonic-crystal slabs, stacked vertically on top of each other, have large absorption that surpasses the Lambertian limit over a broad bandwidth and angular range.

  14. Determination of carnitine and acylcarnitines in plasma by high-performance liquid chromatography/electrospray ionization ion trap tandem mass spectrometry.

    PubMed

    Vernez, Laurence; Wenk, Markus; Krähenbühl, Stephan

    2004-01-01

    A high-performance liquid chromatography/mass spectrometry method was developed for the determination of carnitine, its biosynthetic precursor butyrobetaine, and eight acylcarnitines in plasma. The procedure includes a solid-phase extraction for carnitine and short- and medium-chain acylcarnitines, and a liquid-liquid extraction for protein-bound long-chain acylcarnitines, followed by separation on a reversed-phase column in the presence of a volatile ion-pairing reagent. Detection was achieved using an ion-trap mass spectrometer run in the tandem mass spectrometry (MS/MS) mode. The choice of the matrix for calibrators, used for quantification of these endogenous compounds, was also investigated. Validation was performed for standard quality controls diluted with 4% bovine serum albumin solution and for spiked plasma quality control samples at concentrations between 0.5 and 80 micromol/L, depending on the compound. Intra- and inter-day precisions for the determination of carnitine were below 3.4% and accuracies were between 95.2 and 109.0%. Application of the method to the diagnosis of pathological acylcarnitine profiles of metabolic disorders in a patient suffering from methylmalonic aciduria is presented. The method allows quantification of carnitine, butyrobetaine, acetylcarnitine and propionylcarnitine, and semiquantitative analysis of medium- and long-chain acylcarnitines. In contrast with other methods, no derivatization step is needed. PMID:15164354

  15. Validation of a new liquid chromatography- tandem mass spectrometry ion-trap technique for the simultaneous determination of thirteen anticoagulant rodenticides, drugs, or natural products.

    PubMed

    Fourel, Isabelle; Hugnet, Christophe; Goy-Thollot, Isabelle; Berny, Philippe

    2010-03-01

    The purpose of this study was to develop and validate a liquid chromatography-tandem mass spectrometry method for the identification and quantification of anticoagulant (anti-vitamin K or AVK) compounds, including rodenticides, drugs, and natural products because no published method could be found. The proposed method is based on ion-trap technology with electrospray ionization (ESI) and multiple reaction monitoring (MRM) technique. Each AVK is identified by means of its retention time, precursor ion, and two product ions. Plasma samples are extracted by liquid-liquid partition on Toxi-tube B((R)). The method was validated on dog plasma and gave good results in terms of specificity, linearity, and percent recovery for the 14 AVK tested (warfarin, acenocoumarol, bromadiolone, brodifacoum, chlorophacinone, coumatetralyl, dicoumarol, difenacoum, difethialone, flocoumafen, fluindione, phenindione, and tioclomarol). The limits of detection ranged from 5 to 25 ng/mL. Intraday repeatability was good, but interday repeatability was more variable though still sufficient for our diagnostic purposes. The technique was successfully applied in a series of clinical investigations to demonstrate its applicability in various animal species and gave very high sensitivity and specificity results. PMID:20223102

  16. Analysis of the diastereoisomers of the cysteinylated aroma precursor of 3-sulfanylhexanol in Vitis vinifera grape must by gas chromatography coupled with ion trap tandem mass spectrometry.

    PubMed

    Thibon, Cécile; Shinkaruk, Svitlana; Tominaga, Takatoshi; Bennetau, Bernard; Dubourdieu, Denis

    2008-03-01

    The diastereoisomeric distribution of S-3-(hexan-1-ol)cysteine (P-3SH), the cysteinylated precursor of 3-sulfanylhexan-1-ol (3SH) in Vitis vinifera grape juice, was determined by a new method. This procedure is based on the purification of P-3SH in a small volume of must (500 microL) by affinity chromatography, followed by the separation of chiral molecules in derivative forms by gas chromatography coupled with ion trap tandem mass spectrometry (GC-MS/MS). The diastereoisomers were easily separated using heptafluorobutyric anhydride and heptafluorobutanol (HFBA and HFOH) as derivatization reagents. Method validation was conducted using samples of grape juice, synthetic must, fermenting must, and wine that were fortified with P-3SH at concentrations of 0.6 and 2.5 microM. The relative standard deviation (RSD) and limit of detection (LOD) of the GC-MS/MS method were 4.6% and 1.5 nM, respectively. P-3SH assays in Bordeaux white grape juice affected by Botrytis cinerea showed an unusually increased proportion of the RS form of the precursor (approximately RR:RS=30:70) as compared to a diastereoisomer ratio (in the vicinity of 50:50) in healthy grape juice. PMID:18249409

  17. Multiclass, multiresidue method for the detection of antibiotic residues in distillers grains by liquid chromatography and ion trap tandem mass spectrometry.

    PubMed

    De Alwis, Hemakanthi; Heller, David N

    2010-04-30

    The increased production of ethanol in the US has resulted in large amounts of distillers grains (DG) which is an excellent feed supplement for livestock. However, the use of antimicrobials during ethanol fermentation has led to a growing concern over the possibility of their residues remaining in DG. To enable the detection of antimicrobial residues, a robust LC-MS/MS method was developed that included 13 antibiotics of diverse chemistries, ampicillin, penicillin G, tetracycline, oxytetracycline, chlortetracycline, bacitracin A, virginiamycin M1, chloramphenicol, erythromycin A, clarithromycin, tylosin A, monensin A and streptomycin. The residues were extracted with an aqueous solution of EDTA and trichloroacetic acid followed by methanol. The combined extract was subjected to a two-track cleanup and concentration on either hydrophilic polymeric or weak cation exchange solid phase extraction cartridges. The extracts are analyzed by LC/ion trap tandem mass spectrometry. The method was validated in dry DG matrix. Absolute recoveries of the analytes ranged from 50 to 100%. Accuracy ranged from 89 to 111% based on calibration by processed standards. The limits of detection and relative standard deviation are satisfactory to support future surveillance studies. The method was subsequently tested in three different end-products of DG: distillers dry grains, distillers wet grains and distillers grains solubles. PMID:20304405

  18. Fragmentation energy index for universalization of fragmentation energy in ion trap mass spectrometers for the analysis of chemical weapon convention related chemicals by atmospheric pressure ionization-tandem mass spectrometry analysis.

    PubMed

    Palit, Meehir; Mallard, Gary

    2009-04-01

    The use of mass spectra generated at 70 eV in electron ionization (EI) as a universal standard for EI has helped in the generation of searchable library databases and had a profound influence on the analytical applications of gas chromatography/mass spectrometry (GC/MS), similarly for liquid chromatography tandem mass spectrometry (LC-MS/MS), suggesting a novel method to normalize the collisional energy for the universalization of fragmentation energy for the analysis of Chemical Weapon Convention (CWC)-related chemicals by atmospheric pressure ionization-tandem mass spectrometry (API-MS(n)) using three-dimensional (3D) ion trap instruments. For normalizing fragmentation energy a "fragmentation energy index" (FEI) is proposed which is an arbitrary scale based on the fact of specific MS/MS fragmentation obtained at different collisional energies for the reference chemicals which are not CWC scheduled compounds. FEI 6 for the generation of an MS(n) library-searchable mass spectral database is recommended. PMID:19331429

  19. Characterization of gallotannins from Astronium species by flow injection analysis- electrospray ionization-ion trap-tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of- flight mass spectrometry.

    PubMed

    da Silva, Viviane Cândida; Napolitano, Assunta; Eletto, Daniela; Rodrigues, Clenilson Martins; Pizza, Cosimo; Vilegas, Wagner

    2011-01-01

    The species Astronium urundeuva (Allemao) Engl. and Astronium graveolens Jacq., which are used in Brazilian folk medicine to treat allergies, inflammation, diarrhea and ulcers, were investigated for their composition. The aim of this study was to define a rapid and reliable analytical approach, based on the flow-injection analysis-electrospray ionization-ion trap-tandem mass spectrometry (FIA-ESI-IT-MS-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-ToF-MS), to investigate the full range of hydrolyzable tannins present in the extracts of these Astronium species. The MALDI-ToF-MS analysis allowed us to ascertain the presence of hydrolysable tannins in both Astronium species as a series of gallotannins with degrees of polymerization of 7 to 13 galloyl units. Moreover, the analysis by FIA-ESI-IT-MS-MS, as well as confirming this result and chemically defining gallotannins as galloylglucose compounds, highlighted the presence of further classes of hydrolysable tannins, such as hexahydrodiphenoyl esters of glucose and some gallic acid derivatives, providing information about their structure by a careful study of their fragmentation patterns. Finally, the evaluation of the number of positional isomers of gallotannins occurring in both Astronium species was obtained by high-performance liquid chromatography-electrospray ionization-ion trap mass spectrometry (HPLC/ESI-IT-MS). This is the first mass spectrometric evidence relating to the existence of gallotannins in Astronium genus. PMID:22006629

  20. Validation of an analytical method for analysis of cannabinoids in hair by headspace solid-phase microextraction and gas chromatography-ion trap tandem mass spectrometry.

    PubMed

    Emídio, Elissandro Soares; Prata, Vanessa de Menezes; Dórea, Haroldo Silveira

    2010-06-18

    The development of an analytical method for the determination of Delta(9)-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in samples of human hair is described. Samples were subjected to a procedure based on the combination of headspace solid-phase microextraction (HS-SPME) with gas chromatography linked with mass spectrometry operating in tandem mode (GC-MS/MS). A 10 mg aliquot of sample was firstly decontaminated using petroleum ether, deionized water and dichloromethane (2 mL of each solvent), for 10 min under sonication, and then digested in alkaline solution (1 mol L(-1) NaOH). The method variables evaluated were pH, mass of hair, fiber type, extraction temperature, desorption time, ionic strength, pre-equilibrium time and extraction time. Parameters concerning operation of the tandem mode MS/MS were also assessed and optimized. Validation of the method demonstrated excellent linearity in the range 0.1-8.0 ng mg(-1), with regression coefficients better than 0.994. Precision was determined using two different concentrations (upper and lower limits of the linear range), and RSD values were between 6.6 and 16.4%. Absolute recoveries (measured in triplicate) were in the range 1.1-8.7%, and limits of detection and quantification were 0.007-0.031 ng mg(-1) and 0.012-0.062 ng mg(-1), respectively. The LOQ for THC (0.062 ng mg(-1)) was below the cut-off value (LOQ < or = 0.1 ng mg(-1)) established by the Society of Hair Testing (SOHT), the Society of Toxicological and Forensic Chemistry (STFCh) and the Société Française de Toxicologie Analytique (SFTA). The optimized SPME method was applied in analysis of hair samples from Cannabis drug users, showing that CBN and CBD were present in all samples analyzed. PMID:20685418

  1. Characterizing the gas phase ion chemistry of an ion trap mobility spectrometry based explosive trace detector using a tandem mass spectrometer.

    PubMed

    Kozole, Joseph; Tomlinson-Phillips, Jill; Stairs, Jason R; Harper, Jason D; Lukow, Stefan R; Lareau, Richard T; Boudries, Hacene; Lai, Hanh; Brauer, Carolyn S

    2012-09-15

    A commercial-off-the-shelf (COTS) ion trap mobility spectrometry (ITMS) based explosive trace detector (ETD) has been interfaced to a triple quadrupole mass spectrometer (MS/MS) for the purpose of characterizing the gas phase ion chemistry intrinsic to the ITMS instrument. The overall objective of the research is to develop a fundamental understanding of the gas phase ionization processes in the ITMS based ETD to facilitate the advancement of its operational effectiveness as well as guide the development of next generation ETDs. Product ion masses, daughter ion masses, and reduced mobility values measured by the ITMS/MS/MS configuration for a suite of nitro, nitrate, and peroxide containing explosives are reported. Molecular formulas, molecular structures, and ionization pathways for the various product ions are inferred using the mass and mobility data in conjunction with density functional theory. The predominant product ions are identified as follows: [TNT-H](-) for trinitrotoluene (TNT), [RDX+Cl](-) for cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), [NO(3)](-) for ethylene glycol dinitrate (EGDN), [NG+NO(3)](-) for nitroglycerine (NG), [PETN+NO(3)](-) for pentaerythritol tetranitrate (PETN), [HNO(3)+NO(3)](-) for ammonium nitrate (NH(4)NO(3)), [HMTD-NC(3)H(6)O(3)+H+Cl](-) for hexamethylene triperoxide diamine (HMTD), and [(CH(3))(2)CNH(2)](+) for triacetone triperoxide (TATP). The predominant ionization pathways for the formation of the various product ions are determined to include proton abstraction, ion-molecule attachment, autoionization, first-order and multi-order thermolysis, and nucleophilic substitution. The ion trapping scheme in the reaction region of the ITMS instrument is shown to increase predominant ion intensities relative to the secondary ion intensities when compared to non-ion trap operation. PMID:22967626

  2. Identification of epoxide functionalities in protonated monofunctional analytes by using ion/molecule reactions and collision-activated dissociation in different ion trap tandem mass spectrometers.

    PubMed

    Eismin, Ryan J; Fu, Mingkun; Yem, Sonoeun; Widjaja, Fanny; Kenttämaa, Hilkka I

    2012-01-01

    A mass spectrometric method has been delineated for the identification of the epoxide functionalities in unknown monofunctional analytes. This method utilizes gas-phase ion/molecule reactions of protonated analytes with neutral trimethyl borate (TMB) followed by collision-activated dissociation (CAD) in an ion trapping mass spectrometer (tested for a Fourier-transform ion cyclotron resonance and a linear quadrupole ion trap). The ion/molecule reaction involves proton transfer from the protonated analyte to TMB, followed by addition of the analyte to TMB and elimination of methanol. Based on literature, this reaction allows the general identification of oxygen-containing analytes. Vinyl and phenyl epoxides can be differentiated from other oxygen-containing analytes, including other epoxides, based on the loss of a second methanol molecule upon CAD of the addition/methanol elimination product. The only other analytes found to undergo this elimination are some amides but they also lose O = B-R (R = group bound to carbonyl), which allows their identification. On the other hand, other epoxides can be differentiated from vinyl and phenyl epoxides and from other monofunctional analytes based on the loss of (CH(3)O)(2)BOH or formation of protonated (CH(3)O)(2)BOH upon CAD of the addition/methanol elimination product. For propylene oxide and 2,3-dimethyloxirane, the (CH(3)O)(2)BOH fragment is more basic than the hydrocarbon fragment, and the diagnostic ion (CH(3)O)(2)BOH (2) (+) is formed. These reactions involve opening of the epoxide ring. The only other analytes found to undergo (CH(3)O)(2)BOH elimination are carboxylic acids, but they can be differentiated from the rest based on several published ion/molecule reaction methods. Similar results were obtained in the Fourier-transform ion cyclotron resonance and linear quadrupole ion trap mass spectrometer. PMID:22002227

  3. Identification of Epoxide Functionalities in Protonated Monofunctional Analytes by Using Ion/Molecule Reactions and Collision-Activated Dissociation in Different Ion Trap Tandem Mass Spectrometers

    NASA Astrophysics Data System (ADS)

    Eismin, Ryan J.; Fu, Mingkun; Yem, Sonoeun; Widjaja, Fanny; Kenttämaa, Hilkka I.

    2012-01-01

    A mass spectrometric method has been delineated for the identification of the epoxide functionalities in unknown monofunctional analytes. This method utilizes gas-phase ion/molecule reactions of protonated analytes with neutral trimethyl borate (TMB) followed by collision-activated dissociation (CAD) in an ion trapping mass spectrometer (tested for a Fourier-transform ion cyclotron resonance and a linear quadrupole ion trap). The ion/molecule reaction involves proton transfer from the protonated analyte to TMB, followed by addition of the analyte to TMB and elimination of methanol. Based on literature, this reaction allows the general identification of oxygen-containing analytes. Vinyl and phenyl epoxides can be differentiated from other oxygen-containing analytes, including other epoxides, based on the loss of a second methanol molecule upon CAD of the addition/methanol elimination product. The only other analytes found to undergo this elimination are some amides but they also lose O = B-R (R = group bound to carbonyl), which allows their identification. On the other hand, other epoxides can be differentiated from vinyl and phenyl epoxides and from other monofunctional analytes based on the loss of (CH3O)2BOH or formation of protonated (CH3O)2BOH upon CAD of the addition/methanol elimination product. For propylene oxide and 2,3-dimethyloxirane, the (CH3O)2BOH fragment is more basic than the hydrocarbon fragment, and the diagnostic ion (CH3O)2BOH{2/+} is formed. These reactions involve opening of the epoxide ring. The only other analytes found to undergo (CH3O)2BOH elimination are carboxylic acids, but they can be differentiated from the rest based on several published ion/molecule reaction methods. Similar results were obtained in the Fourier-transform ion cyclotron resonance and linear quadrupole ion trap mass spectrometer.

  4. Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

    PubMed

    Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

    2014-05-01

    A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs. PMID:24678766

  5. Assisted solvent extraction and ion-trap tandem mass spectrometry for the determination of polychlorinated biphenyls in mussels. Comparison with other extraction techniques.

    PubMed

    García, I; Ignacio, M; Mouteira, A; Cobas, J; Carro, N

    2008-01-01

    A selective and sensitive analytical method for determination of ten congeners of polychlorinated biphenyls (PCBs 31, 28, 52, 101, 118, 153, 105, 138, 156, and 180) in mussel samples (Mytilus galloprovincialis) based on accelerated solvent extraction (ASE) and gas chromatography-tandem mass spectrometry (GC-MS-MS) is presented in this work. Extraction conditions were optimised using a Plackett-Burman factorial design. The final extracts were analysed after cleanup on alumina columns. The optimised extraction parameters were solvent percentage, sample amount, extraction temperature, pressure, static extraction time, flush percentage, and purge time. The results suggest that PCBs 118, 105, and 180 extractions appeared affected by only one statistically significant factor, pressure, solvent percentage and static extraction time, respectively. Extraction of PCBs 138 and 156 was affected by amount of sample. PCB 138 extraction was also statistically affected by static extraction time and purge time. Quantitative recoveries (64.8-120.3%) were achieved for all PCBs and method precision (RSD < 19%) was satisfactory. PMID:17965854

  6. Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of three barbiturates in pork by ion trap gas chromatography-tandem mass spectrometry (GC/MS/MS) following microwave assisted derivatization.

    PubMed

    Zhao, Haixiang; Wang, Liping; Qiu, Yueming; Zhou, Zhiqiang; Zhong, Weike; Li, Xiang

    2007-03-14

    A new method was developed for the rapid screening and confirmation analysis of barbital, amobarbital and phenobarbital residues in pork by gas chromatography-tandem mass spectrometry (GC/MS/MS) with ion trap MSD. The residual barbiturates in pork were extracted by ultrasonic extraction, cleaned up on a multiwalled carbon nanotubes (MWCNTs) packed solid phase extraction (SPE) cartridge and applied acetone-ethyl acetate (3:7, v/v) mixture as eluting solvent and derivatized with CH3I under microwave irradiation. The methylated barbiturates were separated on a TR-5MS capillary column and detected with an ion trap mass detector. Electron impact ion source (EI) operating MS/MS mode was adopted for identification and external standard method was employed for quantification. One precursor ion m/z 169 was selected for analysis of barbital and amobarbital and m/z 232 was selected for phenobarbital. The product ions were obtained under 1.0 V excitation voltage. Good linearities (linear coefficient R > 0.99) were obtained at the range of 0.5-50 microg kg(-1). Limit of detection (LOD) of barbital was 0.2 microg kg(-1) and that of amobarbital and phenobarbital were both 0.1 microg kg(-1) (S/N > or = 3). Limit of quantification (LOQ) was 0.5 microg kg(-1) for three barbiturates (S/N > or = 10). Satisfying recoveries ranging from 75% to 96% of the three barbiturates spiked in pork were obtained, with relative standard deviations (R.S.D.) in the range of 2.1-7.8%. PMID:17386740

  7. Determination of carnitine and acylcarnitines in urine by high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry.

    PubMed

    Vernez, Laurence; Hopfgartner, Gérard; Wenk, Markus; Krähenbühl, Stephan

    2003-01-17

    A high-performance liquid chromatography-mass spectrometry method has been developed for the simultaneous determination of native carnitine and eight acylcarnitines in urine. The procedure uses a solid-phase extraction on a cation-exchange column and the separation is performed without derivatization within 17 min on a reversed-phase C8 column in the presence of a volatile ion-pairing reagent. The detector was an ion trap mass spectrometer and quantification was carried out in the MS-MS mode. Validation was done for aqueous standards at ranges between 0.75 and 200 micromol/l, depending on the compound. Carnitine was quantified in urine and comparison with a radioenzymatic assay gave a satisfactory correlation (R2 = 0.981). The assay could be successfully applied to the diagnostic of pathological acylcarnitines profile of metabolic disorders in urines of patients suffering from different organic acidurias. PMID:12564691

  8. Comprehensive speciation of low-molecular weight selenium metabolites in mustard seeds using HPLC-electrospray linear trap/Orbitrap tandem mass spectrometry.

    PubMed

    Ouerdane, Laurent; Aureli, Federica; Flis, Paulina; Bierla, Katarzyna; Preud'homme, Hugues; Cubadda, Francesco; Szpunar, Joanna

    2013-09-01

    An analytical methodology based on high-resolution high mass accuracy electrospray ionization (ESI) tandem MS assisted by Se-specific detection using inductively coupled plasma mass spectrometry (ICP MS) was developed for speciation of selenium (Se) in seeds of black mustard (Brassica nigra) grown on Se-rich soil. Size-exclusion LC-ICP MS allowed the determination of the Se distribution according to the molecular mass and the control of the species stability during extraction. The optimization of hydrophilic interaction of LC and cation-exchange HPLC resulted in analytical conditions making it possible to detect and characterize over 30 Se species using ESI MS, including a number of minor (<0.5%) metabolites. Selenoglucosinolates were found to be the most important class of species accounting for at least 15% of the total Se present and over 50% of all the metabolites. They were found particularly unstable during aqueous extraction leading to the loss of Se by volatilization as methylselenonitriles and methylselenoisothiocyanates identified using gas chromatography (GC) with the parallel ICP MS and atmospheric pressure chemical ionization (APCI) MS/MS detection. However, selenoglucosinolates could be efficiently recovered by extraction with 70% methanol. Other classes of identified species included selenoamino acids, selenosugars, selenosinapine and selenourea derivatives. The three types of reactions leading to the formation of selenometabolites were: the Se-S substitution in the metabolic pathway, oxidative reactions of -SeH groups with endogenous biomolecules, and chemical reactions, e.g., esterification, of Se-containing molecules and other biomolecules through functional groups not involving Se. PMID:23925428

  9. Determination of sulfonamide antibiotics and metabolites in liver, muscle and kidney samples by pressurized liquid extraction or ultrasound-assisted extraction followed by liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry (HPLC-QqLIT-MS/MS).

    PubMed

    Hoff, Rodrigo Barcellos; Pizzolato, Tânia Mara; Peralba, Maria do Carmo Ruaro; Díaz-Cruz, M Silvia; Barceló, Damià

    2015-03-01

    Sulfonamides are widely used in human and veterinary medicine. The presence of sulfonamides residues in food is an issue of great concern. Throughout the present work, a method for the targeted analysis of 16 sulfonamides and metabolites residue in liver of several species has been developed and validated. Extraction and clean-up has been statistically optimized using central composite design experiments. Two extraction methods have been developed, validated and compared: i) pressurized liquid extraction, in which samples were defatted with hexane and subsequently extracted with acetonitrile and ii) ultrasound-assisted extraction with acetonitrile and further liquid-liquid extraction with hexane. Extracts have been analyzed by liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry. Validation procedure has been based on the Commission Decision 2002/657/EC and included the assessment of parameters such as decision limit (CCα), detection capability (CCβ), sensitivity, selectivity, accuracy and precision. Method׳s performance has been satisfactory, with CCα values within the range of 111.2-161.4 µg kg(-1), limits of detection of 10 µg kg(-1) and accuracy values around 100% for all compounds. PMID:25618734

  10. High-performance liquid chromatography with diode array detection coupled to electrospray time-of-flight and ion-trap tandem mass spectrometry to identify phenolic compounds from a lemon verbena extract.

    PubMed

    Quirantes-Piné, R; Funes, L; Micol, V; Segura-Carretero, A; Fernández-Gutiérrez, A

    2009-07-10

    High-performance liquid chromatography with diode array and electrospray ionization mass spectrometric detection was used to carry out the comprehensive characterization of a lemon verbena extract with demonstrated antioxidant and antiinflammatory activity. Two different MS techniques have been coupled to HPLC: on one hand, time-of-flight mass spectrometry, and on the other hand, tandem mass spectrometry on an ion-trap. The use of a small particle size C18 column (1.8 microm) provided a great resolution and made possible the separation of several isomers. The UV-visible spectrophotometry was used to delimit the class of phenolic compound and the accurate mass measurements on time-of-flight spectrometer enabled to identify the compounds present in the extract. Finally, the fragmentation pattern obtained in MS-MS experiments confirmed the proposed structures. This procedure was able to determine many well-known phenolic compounds present in lemon verbena such as verbascoside and its derivatives, diglucuronide derivatives of apigenin and luteolin, and eukovoside. Also gardoside, verbasoside, cistanoside F, theveside, campneoside I, chrysoeriol-7-diglucuronide, forsythoside A and acacetin-7-diglucuronide were found for the first time in lemon verbena. PMID:19500792

  11. Chemometrics for comprehensive analysis of nucleobases, nucleosides, and nucleotides in Siraitiae Fructus by hydrophilic interaction ultra high performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry.

    PubMed

    Zhou, Guisheng; Wang, Mengyue; Xu, Renjie; Li, Xiao-Bo

    2015-10-01

    A rapid and sensitive hydrophilic interaction ultra high performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry method was validated for the simultaneous determination of 20 nucleobases, nucleosides, and nucleotides (within 3.5 min), and then was employed to test the functional food of Luo-Han-Guo samples. The analysis showed that the Luo-Han-Guo was rich in guanosine and uridine, but contained trace levels of the other target compounds. Chemometrics methods were employed to identify 40 batches of Luo-Han-Guo samples from different cultivated forms, regions and varieties. Unsupervised hierarchical cluster analysis and principal component analysis were used to classify Luo-Han-Guo samples based on the level of the 20 target compounds, and the supervised learning method of counter propagation artificial neural network was utilized to further separate clusters and validate the established model. As a result, the samples could be clustered into three primary groups, in which correlation with cultivated varieties was observed. The present strategy could be applied to the investigation of other edible plants containing nucleobases, nucleosides, or nucleotides. PMID:26249158

  12. Dispersive liquid-liquid microextraction for the determination of macrocyclic lactones in milk by liquid chromatography with diode array detection and atmospheric pressure chemical ionization ion-trap tandem mass spectrometry.

    PubMed

    Campillo, Natalia; Viñas, Pilar; Férez-Melgarejo, Gema; Hernández-Córdoba, Manuel

    2013-03-22

    Eprinomectin (EPRI), abamectin (ABA), doramectin (DOR), moxidectin (MOX) and ivermectin (IVM) were determined in milk samples using dispersive liquid-liquid microextraction (DLLME) and liquid chromatography with diode array detection (LC-DAD) coupled to atmospheric pressure chemical ionization in negative ion mode ion-trap tandem mass spectrometry (APCI-IT-MS/MS). Milk proteins were removed by precipitation with trichloroacetic acid and the analytes were preconcentrated using 2mL of acetonitrile containing 200μL of chloroform as extraction mixture. The effect of several parameters for the liquid-liquid microextraction efficiency was evaluated. Standard additions method was used for quantification purposes, the correlation coefficients were better than 0.9970 in all cases and the quantification limits ranged from 1.0 to 4.7ngg(-1) and from 0.1 to 2.4ngg(-1) when using DAD and MS, respectively. The DLLME-LC-APCI-IT-MS/MS optimized method was successfully applied to different milk samples and none of the studied analytes was detected in the samples studied. The recoveries for milk samples spiked at concentration levels ranging between 0.5 and 50ngg(-1), depending on the compound, were between 89.5 and 105%, with relative standard deviations lower than 9% (n=135). Simplicity, rapidity and reliability are important advantages of the proposed method, while the sample preparation step can be regarded as environmentally friendly. PMID:23415139

  13. Determination of tylosins A, B, C and D in bee larvae by liquid chromatography coupled to ion trap-tandem mass spectrometry.

    PubMed

    Bernal, J; Martín, Ma T; Toribio, L; Martín-Hernández, R; Higes, M; Bernal, J L; Nozal, M J

    2011-06-01

    A LC-MS/MS method has been developed to simultaneously quantify tylosins A, B, C and D in bee larvae, compounds currently used to treat one of the most lethal diseases affecting honey bees around the world, American Foulbrood (AFB). The influence of different aqueous media, temperature and light exposure on the stability of these four compounds was studied. The analytes were extracted from bee larvae with methanol and chromatographic separation was achieved on a Luna C(18) (150 × 4.6 mm i.d.) using a ternary gradient composed of a diluted formic acid, methanol and acetonitrile mobile phase. To facilitate sampling, bee larvae were initially dried at 60°C for 4h and afterwards, they were diluted to avoid problems of pressure. MSD-Ion Trap detection was employed with electrospray ionization (ESI). The calibration curves were linear over a wide range of concentrations and the method was validated as sensitive, precise and accurate within the limits of quantification (LOQ, 1.4-4.0 ng/g). The validated method was successfully employed to study bee larvae in field tests of bee hives treated with two formulations containing tylosin. In both cases it was evident that the minimal inhibitory concentration (MIC) had been reached. PMID:21498134

  14. Real-time air monitoring of mustard gas and Lewisite 1 by detecting their in-line reaction products by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow ion introduction.

    PubMed

    Okumura, Akihiko; Takada, Yasuaki; Watanabe, Susumu; Hashimoto, Hiroaki; Ezawa, Naoya; Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Kondo, Tomohide; Nagashima, Hisayuki; Nagoya, Tomoki

    2015-01-20

    A new method enabling sensitive real-time air monitoring of highly reactive chemical warfare agents, namely, mustard gas (HD) and Lewisite 1 (L1), by detecting ions of their in-line reaction products instead of intact agents, is proposed. The method is based on corona discharge-initiated atmospheric pressure chemical ionization coupled with ion trap tandem mass spectrometry (MS(n)) via counterflow ion introduction. Therefore, it allows for highly sensitive and specific real-time detection of a broad range of airborne compounds. In-line chemical reactions, ionization reactions, and ion fragmentations of these agents were investigated. Mustard gas is oxygenated in small quantity by reactive oxygen species generated in the corona discharge. With increasing air humidity, the MS(2) signal intensity of protonated molecules of mono-oxygenated HD decreases but exceeds that of dominantly existing intact HD. This result can be explained in view of proton affinity. Lewisite 1 is hydrolyzed and oxidized. As the humidity increases from zero, the signal of the final product, namely, didechlorinated, dihydroxylated, and mono-oxygenated L1, quickly increases and reaches a plateau, giving the highest MS(2) and MS(3) signals among those of L1 and its reaction products. The addition of minimal moisture gives the highest signal intensity, even under low humidity. The method was demonstrated to provide sufficient analytical performance to meet the requirements concerning hygienic management and counter-terrorism. It will be the first practical method, in view of sensitivity and specificity, for real-time air monitoring of HD and L1 without sample pretreatment. PMID:25553788

  15. DNA Separation Using Photoelectrophoretic Traps

    SciTech Connect

    Braiman, Avital; Thundat, Thomas George; Rudakov, Fedor M

    2011-01-01

    In our recent publications we presented a design that allows formation of highly localized and optically controlled electrophoretic traps. 1,2 We demonstrated that electrophoretic traps can be utilized for biomolecule photoconcentration, optically directed transport, and separation by size. 1,2 In the current publication we suggest a hybrid design for biomolecule separation which implements electrophoretic traps in tandem with well-established electrophoretic techniques. We perform Monte Carlo simulations that demonstrate that the resolution of well-established electrophoretic techniques can be greatly enhanced by introducing photoelectrophoretic traps.

  16. Comparative study of comprehensive gas chromatography-nitrogen chemiluminescence detection and gas chromatography-ion trap-tandem mass spectrometry for determining nicotine and carcinogen organic nitrogen compounds in thirdhand tobacco smoke.

    PubMed

    Ramírez, Noelia; Vallecillos, Laura; Lewis, Alastair C; Borrull, Francesc; Marcé, Rosa M; Hamilton, Jacqueline F

    2015-12-24

    Thirdhand tobacco smoke (THS) constitutes a poorly understood pathway of exposure of non-smokers, especially toddlers, to tobacco-related carcinogens. However, to date most of the carcinogens present in tobacco smoke have not been detected in THS and, therefore, the significance of THS health risk is still unknown. In this study, we have compared the performance of two analytical methods - one based on gas chromatography coupled to ion trap mass spectrometry detection (GC-IT-MS) and the other on comprehensive two-dimensional gas chromatography coupled to a nitrogen chemiluminescence detector (GC×GC-NCD) - for simultaneously determining, in settled house dust, the presence of 16 organic nitrogen carcinogens already detected in tobacco smoke. The target compounds included four aromatic amines, two nitrocompounds, eight N-nitrosamines and two tobacco-specific nitrosamines, as well as nicotine as a tobacco marker. Dust samples were extracted using in-cell clean up pressurized liquid extraction with silica as clean up sorbent and ethyl acetate as the organic solvent, with average recovery of 89%. Although GC-IT-MS, using chemical ionization with methanol and tandem MS, performed well, the optimized GC×GC-NCD gave lower limits of detection (from 4 to 22ngg(-1)) and better repeatability and reproducibility a low concentration levels (%RSD<8%) and, therefore, was applicable for determining these different groups of carcinogens without the need for derivatization prior to the GC analysis. The performance of the optimized PLE/GC×GC-NCD method was tested by quantifying the target compounds in house dust samples from smokers' and non-smokers' homes. The median carcinogen compounds detected was 3.8μgg(-1) and 1.1μgg(-1) in smokers' and non-smokers' house dust, respectively. In this study, we have detected highly carcinogenic aromatic amines and nitro compounds for the first time in settled house dust complementing the state of knowledge of THS composition and providing

  17. Tandem betatron

    DOEpatents

    Keinigs, Rhonald K.

    1992-01-01

    Two betatrons are provided in tandem for alternately accelerating an electron beam to avoid the single flux swing limitation of conventional betatrons and to accelerate the electron beam to high energies. The electron beam is accelerated in a first betatron during a period of increasing magnetic flux. The eletron beam is extracted from the first betatron as a peak magnetic flux is reached and then injected into a second betatron at a time of minimum magnetic flux in the second betatron. The cycle may be repeated until the desired electron beam energy is obtained. In one embodiment, the second betatron is axially offset from the first betatron to provide for electron beam injection directly at the axial location of the beam orbit in the second betatron.

  18. Tandem Couture

    PubMed Central

    Ericksen, Spencer S.; Boileau, Andrew J.

    2008-01-01

    Receptor subunits in the Cys-loop superfamily assemble to form channels as homopentamers or heteropentamers, expanding functional diversity through modularity. Expression of two or more compatible subunit types can lead to various receptor assemblies or subtypes. However, what may be good for diversity in vivo may be undesirable for the bench scientist, because we often wish to reduce our analyses to a single receptor subtype. By linking two or more subunits, creating tandems or concatamers, we can control stoichiometry and limit expression to exactly one receptor subtype. In this fashion, receptors with mixed subunit subtypes and heterozygous mutations can be separated from a mixture and can be described in detail. However, several recent studies have shown that this may be more easily conceived than accomplished, because several unforeseen problems have arisen. Concatamers can degrade, linkers can sometimes be clipped after or during translation, and one subunit may “loop out” or even become part of a second (now linked) pentamer with different characteristics. Some strategies have been developed to overcome these drawbacks, and the resultant new information that has begun to emerge has revitalized the study of these receptors in heterologous expression systems. PMID:17519509

  19. Trapped Surfaces

    NASA Astrophysics Data System (ADS)

    Senovilla, José M. M.

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are shown, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are discussed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance discussed.

  20. Trapped Surfaces

    NASA Astrophysics Data System (ADS)

    Senovilla, José M. M.

    2013-03-01

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are pointed out, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are analyzed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance briefly discussed.

  1. Characterization of proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by Flow Injection Analysis-Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry.

    PubMed

    Tala, Viviane Raïssa Sipowo; Candida da Silva, Viviane; Rodrigues, Clenilson Martins; Nkengfack, Augustin Ephrem; dos Santos, Lourdes Campaner; Vilegas, Wagner

    2013-01-01

    The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae) roots and barks by Liquid Chromatography-Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities. PMID:23455671

  2. Optical trapping

    PubMed Central

    Neuman, Keir C.; Block, Steven M.

    2006-01-01

    Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. PMID:16878180

  3. COLD TRAPS

    DOEpatents

    Thompson, W.I.

    1958-09-30

    A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.

  4. Fast and comprehensive multi-residue analysis of a broad range of human and veterinary pharmaceuticals and some of their metabolites in surface and treated waters by ultra-high-performance liquid chromatography coupled to quadrupole-linear ion trap tandem mass spectrometry.

    PubMed

    Gros, Meritxell; Rodríguez-Mozaz, Sara; Barceló, Damià

    2012-07-27

    The present work describes the development of an analytical method, based on automated off-line solid phase extraction (SPE) followed by ultra-high-performance liquid chromatography coupled to quadrupole linear ion trap tandem mass spectrometry (UPLC-QqLIT) for the determination of 81 pharmaceutical residues, covering various therapeutic groups, and some of their main metabolites, in surface and treated waters (influent and effluent wastewaters, river, reservoir, sea and drinking water). For unequivocal identification and confirmation, two selected reaction monitoring (SRM) transitions per compound are monitored. Quantification is performed by the internal standard approach, indispensable to correct matrix effects. Moreover, to obtain an extra tool for confirmation of positive findings, an information dependent acquisition (IDA) experiment was performed, with SRM as survey scan and an enhanced product ion (EPI) scan as dependent scan. Compound identification was carried out by library search, matching the EPI spectra achieved at one fixed collision energy with those present in a library. The main advantages of the method are automation and speed-up of sample preparation by the reduction of extraction volumes for some matrices, the fast separation of a big number of pharmaceuticals, its high sensitivity (limits of detection in the low ng/L range), selectivity, due to the use of tandem mass spectrometry, reliability since a significant number of isotopically labeled compounds are used as internal standards for quantification and finally, the analysis of tap, reservoir and sea waters, since information about occurrence of pharmaceuticals in these matrices is still sparse. As part of the validation procedure, the method developed was applied to the analysis of pharmaceutical residues in waste and surface waters from different sites in Catalonia (North East of Spain). PMID:22704668

  5. Identification and determination of 34 water-soluble synthetic dyes in foodstuff by high performance liquid chromatography-diode array detection-ion trap time-of-flight tandem mass spectrometry.

    PubMed

    Li, Xiu Qin; Zhang, Qing He; Ma, Kang; Li, Hong Mei; Guo, Zhen

    2015-09-01

    An accurate method combining high performance liquid chromatography (HPLC) with diode array detection (DAD) and ion-trap time-of-flight mass spectrometry (IT-TOF/MS) was developed for simultaneous identification and quantification of 34 water-soluble synthetic dyes in foodstuff. Fragmentation patterns of synthetic dyes were proposed based on IT-TOF/MS. The molecular ion [M+H](+) was not observed in the conventional single-stage mass spectra for most of synthetic dyes. The single-stage mass spectra of synthetic dyes all afforded the diagnostic ions [(M-nNa+nH)+H](+) or [(M-nNa+nH)-H](-) in the positive or negative mode. Doubly charged ions were the characteristic ions of azo dyes. An HPLC-DAD method was developed to analyze 34 synthetic dyes in foodstuffs. The limits of detection (LOD) for the dyes were 0.01-0.05 μg/mL. The recoveries were between 76.1% and 105.0% with a RSD ranging from 1.4% to 6.4%. This method was successfully applied to analyzing the 34 water-soluble synthetic dyes in 21 commercial foods. PMID:25842343

  6. High-Performance Liquid Chromatography with Diode Array Detector and Electrospray Ionization Ion Trap Time-of-Flight Tandem Mass Spectrometry to Evaluate Ginseng Roots and Rhizomes from Different Regions.

    PubMed

    Wang, Hong-Ping; Zhang, You-Bo; Yang, Xiu-Wei; Yang, Xin-Bao; Xu, Wei; Xu, Feng; Cai, Shao-Qing; Wang, Ying-Ping; Xu, Yong-Hua; Zhang, Lian-Xue

    2016-01-01

    Ginseng, Panax ginseng C. A. Meyer, is an industrial crop in China and Korea. The functional components in ginseng roots and rhizomes are characteristic ginsenosides. This work developed a new high-performance liquid chromatography coupled with electrospray ionization ion trap time-of-flight multistage mass spectrometry (LC-ESI-IT-TOF-MS(n)) method to identify the triterpenoids. Sixty compounds (1-60) including 58 triterpenoids were identified from the ginseng cultivated in China. Substances 1, 2, 7, 15-20, 35, 39, 45-47, 49, 55-57, 59, and 60 were identified for the first time. To evaluate the quality of ginseng cultivated in Northeast China, this paper developed a practical liquid chromatography-diode array detection (LC-DAD) method to simultaneously quantify 14 interesting ginsenosides in ginseng collected from 66 different producing areas for the first time. The results showed the quality of ginseng roots and rhizomes from different sources was different due to growing environment, cultivation technology, and so on. The developed LC-ESI-IT-TOF-MS(n) method can be used to identify many more ginsenosides and the LC-DAD method can be used not only to assess the quality of ginseng, but also to optimize the cultivation conditions for the production of ginsenosides. PMID:27171066

  7. Application of a hybrid ordered mesoporous silica as sorbent for solid-phase multi-residue extraction of veterinary drugs in meat by ultra-high-performance liquid chromatography coupled to ion-trap tandem mass spectrometry.

    PubMed

    Casado, Natalia; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; Sierra, Isabel

    2016-08-12

    A quick, sensitive and selective analytical reversed-phase multi-residue method using ultra-high performance liquid chromatography coupled to an ion-trap mass spectrometry detector (UHPLC-IT-MS/MS) operating in both positive and negative ion mode was developed for the simultaneous determination of 23 veterinary drug residues (β-blockers, β-agonists and Non-Steroidal Anti-inflammatory Drugs (NSAIDs)) in meat samples. The sample treatment involved a liquid-solid extraction followed by a solid-phase extraction (SPE) procedure. SBA-15 type mesoporous silica was synthetized and modified with octadecylsilane, and the resulting hybrid material (denoted as SBA-15-C18) was applied and evaluated as SPE sorbent in the purification of samples. The materials were comprehensively characterized, and they showed a high surface area, high pore volume and a homogeneous distribution of the pores. Chromatographic conditions and extraction procedure were optimized, and the method was validated according to the Commission Decision 2002/657/EC. The method detection limits (MDLs) and the method quantification limits (MQLs) were determined for all the analytes in meat samples and found to range between 0.01-18.75μg/kg and 0.02-62.50μg/kg, respectively. Recoveries for 15 of the target analytes ranged from 71 to 98%. In addition, for comparative purpose SBA-15-C18 was evaluated towards commercial C18 amorphous silica. Results revealed that SBA-15-C18 was clearly more successful in the multi-residue extraction of the 23 mentioned analytes with higher recovery values. The method was successfully tested to analyze prepacked preparations of mince bovine meat. Traces of propranolol, ketoprofen and diclofenac were detected in some samples. PMID:27412322

  8. Tandem mobile robot system

    DOEpatents

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  9. Online eluent-switching technique coupled anion-exchange liquid chromatography–ion trap tandem mass spectrometry for analysis of non-steroidal anti-inflammatory drugs in pig serum.

    PubMed

    Chang, Kai Chun; Lin, Jyh Shiun; Cheng, Cheanyeh

    2015-11-27

    A novel method for online extraction, pH-gradient separation, and analysis of nine non-steroidal anti-inflammatory drugs (NSAIDs) was developed by coupling online eluent-switching technique to single anion-exchange chromatographic column/ion trap mass spectrometer (MS) and used for monitoring NSAIDs residues in pig serum. A neutral eluent and a pH-gradient eluent were used for extraction and separation of NSAIDs, respectively. Each of nine NSAIDs has an MS precursor ion of either [M−H]− or [M−Na]−. The extracted ion chromatogram for a specific product ion of each NSAID was used for its quantitative analysis. The dynamic linear ranges of calibration curves were all 0–200 ng mL−1 (R2 > 0.9950). The analysis accuracies estimated by spiking standard concentrations at 20, 100, and 200 ng mL−1 were 80.5–99.9%. The corresponding intra-day and inter-day precisions (RSD%) were 2.5–14.5% and 2.9–15.2%, respectively. The limit of detection/limit of quantitation of NSAIDs were 1.3/4.3, 0.5/1.6, 0.2/0.5, 2.5/8.2, 1.5/4.9, 0.6/2.1, 0.6/2.0, 0.5/1.7, and 0.6/2.1 ng mL−1 for carprofen, diclofenac, flunixin, ibuprofen, ketoprofen, meclofenamic acid sodium, mefenamic acid, niflumic acid, and tolfenamic acid, respectively. After 1 h injection of a dose containing 2 mg kg−1 weight pig of flunixin and tolfenamic acid to the pigs, a residue amount of 3480 ± 36 ng mL−1 and 431 ± 13 ng mL−1, respectively, was reached for the incurred pig serum specimens and both residues were reduced to about 20 ng mL−1 at the time of 24 h. PMID:26601710

  10. Reactor issues for tandem mirrors operating in the negative-potential mode

    SciTech Connect

    Perkins, L.J.; Campbell, R.B.

    1985-12-02

    During 1985, interest has been revived at LLNL in tandem mirrors operating in the negative-potential mode. The negative tandem is formed by combining ECRH-sustained hot electron end cell plasmas with pumping mechanisms to remove trapped ions from the end cells. No sloshing ions are required. The resulting negative potential in the end cells confines the central cell electrons. The requirement of charge neutrality causes the ambipolar potential of the central cell to become negative relative to the end wall (hence, the name ''negative' tandem mirror), thereby providing central cell ion confinement. This potential distribution is the exact inverse of the axial distribution for the conventional (positive) tandem mirror without thermal barriers. In the negative tandem mirror, central cell electrons are confined electrostatically, end cell electrons are confined magnetically, and ions are confined electrostatically everywhere. In this report, we briefly assess the reactor issues pertinent to the operation of the tandem mirror in the negative mode. 7 refs., 5 figs.

  11. Ripple Trap

    NASA Technical Reports Server (NTRS)

    2006-01-01

    3 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a cratered plain in the Athabasca Vallis region of Mars. Remarkably, the cratered plain in this scene is essentially free of bright, windblown ripples. Conversely, the lava flow apparently acted as a trap for windblown materials, illustrated by the presence of the light-toned, wave-like texture over much of the flow. That the lava flow surface trapped windblown sand and granules better than the cratered plain indicates that the flow surface has a rougher texture at a scale too small to resolve in this image.

    Location near: 10.7oN, 204.5oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  12. Tandem Air Propellers - II

    NASA Technical Reports Server (NTRS)

    Lesley, E. P.

    1939-01-01

    Tests of three-blade, adjustable-pitch counterrotating tandem model propellers, adjusted to absorb equal power at maximum efficiency of the combination, were made at Stanford University. The aerodynamic characteristics, for blade-angle settings of 15, 25, 35, 45, 55, and 65 degrees at 0.75R of the forward propeller and for diameters spacings of 8-1/2, 15 and 30% were compared with those of three-blade and six-blade propellers of the same blade form. It was found that, in order to realize the condition of equal power at maximum efficiency, the blade angles for the rear propeller must be generally less than for the forward propeller, the difference increasing the blade angle. The tests showed that, at maximum efficiency, the tandem propellers absorb about double the power of three-blade propellers and about 8% more power than six-blade propellers having the pitch of the forward propeller of the tandem combination. The maximum efficiency of the tandem propellers was found to be from 2-15% greater than for six-blade propellers, the difference varying directly with blade angle. It was also found that the maximum efficiency of the tandem propellers was greater than that of a three-blade propeller for blade angles at 0.75R of 25 degrees or more. The difference in maximum efficiency again varied directly with blade angle, being about 9% for 65 degrees at 0.75R.

  13. Trapped antihydrogen.

    PubMed

    Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jonsell, S; Jørgensen, L V; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; el Nasr, S Seif; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2010-12-01

    Antimatter was first predicted in 1931, by Dirac. Work with high-energy antiparticles is now commonplace, and anti-electrons are used regularly in the medical technique of positron emission tomography scanning. Antihydrogen, the bound state of an antiproton and a positron, has been produced at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature's fundamental symmetries. The charge conjugation/parity/time reversal (CPT) theorem, a crucial part of the foundation of the standard model of elementary particles and interactions, demands that hydrogen and antihydrogen have the same spectrum. Given the current experimental precision of measurements on the hydrogen atom (about two parts in 10(14) for the frequency of the 1s-to-2s transition), subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, model-independent test of CPT. Antihydrogen could also be used to study the gravitational behaviour of antimatter. However, so far experiments have produced antihydrogen that is not confined, precluding detailed study of its structure. Here we demonstrate trapping of antihydrogen atoms. From the interaction of about 10(7) antiprotons and 7 × 10(8) positrons, we observed 38 annihilation events consistent with the controlled release of trapped antihydrogen from our magnetic trap; the measured background is 1.4 ± 1.4 events. This result opens the door to precision measurements on anti-atoms, which can soon be subjected to the same techniques as developed for hydrogen. PMID:21085118

  14. COLD TRAP

    DOEpatents

    Milleron, N.

    1963-03-12

    An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

  15. VACUUM TRAP

    DOEpatents

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  16. Tandem mirror fusion research

    SciTech Connect

    Baldwin, D.E.

    1983-12-02

    The tandem mirror program has evolved considerably in the last decade. Of significance is the viable reactor concept embodied in the MARS design. An aggressive experimental program, culminating in the operation of MFTF-B in late 1986, will provide a firm basis for refining the MARS design as necessary for constructing a reactor prototype in the 1990s.

  17. Tandem BRCT Domains

    PubMed Central

    Mesquita, Rafael D.; Woods, Nicholas T.; Seabra-Junior, Eloy S.; Monteiro, Alvaro N.A.

    2010-01-01

    The cell’s ability to sense and respond to specific stimuli is a complex system derived from precisely regulated protein-protein interactions. Some of these protein-protein interactions are mediated by the recognition of linear peptide motifs by protein modular domains. BRCT (BRCA1 C-terminal) domains and their linear motif counterparts, which contain phosphoserines, are one such pair-wise interaction system that seems to have evolved to serve as a surveillance system to monitor threats to the cell’s genetic integrity. Evidence indicates that BRCT domains found in tandem can cooperate to provide sequence-specific binding of phosphorylated peptides as is the case for the breast and ovarian cancer susceptibility gene BRCA1 and the PAX transcription factor–interacting protein PAXIP1. Particular interest has been paid to tandem BRCT domains as “readers” of signaling events in the form of phosphorylated serine moieties induced by the activation of DNA damage response kinases ATM, ATR, and DNA-PK. However, given the diversity of tandem BRCT-containing proteins, questions remain as to the origin and evolution of this domain. Here, we discuss emerging views of the origin and evolving roles of tandem BRCT domain repeats in the DNA damage response. PMID:21533002

  18. Nanopyramid structure for ultrathin c-Si tandem solar cells.

    PubMed

    Li, Guijun; Li, He; Ho, Jacob Y L; Wong, Man; Kwok, Hoi Sing

    2014-05-14

    Recently, ultrathin crystalline silicon solar cells have gained tremendous interest because they are deemed to dramatically reduce material usage. However, the resulting conversion efficiency is still limited by the incomplete light absorption in such ultrathin devices. In this letter, we propose ultrathin a-Si/c-Si tandem solar cells with an efficient light trapping design, where a nanopyramid structure is introduced between the top and bottom cells. The superior light harvesting results in a 48% and 35% remarkable improvement of the short-circuit current density for the top and bottom cells, respectively. Meanwhile, the use of SiOx mixed-phase nanomaterial helps to provide the maximum light trapping without paying the price of reduced electrical performance, and conversion efficiencies of up to 13.3% have been achieved for the ultrathin tandem cell employing only 8 μm of silicon, which is 29% higher than the result obtained for the planar cell. PMID:24730470

  19. Differentially pumped dual linear quadrupole ion trap mass spectrometer

    SciTech Connect

    Owen, Benjamin C.; Kenttamaa, Hilkka I.

    2015-10-20

    The present disclosure provides a new tandem mass spectrometer and methods of using the same for analyzing charged particles. The differentially pumped dual linear quadrupole ion trap mass spectrometer of the present disclose includes a combination of two linear quadrupole (LQIT) mass spectrometers with differentially pumped vacuum chambers.

  20. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, Ian J.; Wendt, Joel R.

    1994-01-01

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors.

  1. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, I.J.; Wendt, J.R.

    1994-09-06

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors. 8 figs.

  2. Tandem betatron accelerator

    NASA Astrophysics Data System (ADS)

    Keinigs, Rhon K.

    1991-04-01

    1407_50The tandem betatron is a compact, high-current induction accelerator that has the capability to accelerate electrons to an energy of order one gigavolt. Based upon the operating principle of a conventional betatron, the tandem betatron employs two synchronized induction cores operating 180 degrees out of phase. Embedded within the cores are the vacuum chambers, and these are connected by linear transport sections to allow for moving the beam back and forth between the two betatrons. The 180 degree phase shift between the core fluxes permits the circumvention of the flux swing constraint that limits the maximum energy gain of a conventional betatron. By transporting the beam between the synchronized cores, an electron can access more than one acceleration cycle, and thereby continue to gain energy. This added degree of freedom also permits a significant decrease in the size of the magnet system. Biasing coils provide independent control of the confining magnetic field. Provided that efficient beam switching can be performed, it appears feasible that a one gigavolt electron beam can be generated and confined. At this energy, a high current electron beam circulating in a one meter radius orbit could provide a very intense source of short wavelength ((lambda) < 10 nm) synchrotron radiation. This has direct application to the emerging field of x-ray lithography. At more modest energies (10 MeV-30 MeV) a compact tandem betatron could be employed in the fields of medical radiation therapy, industrial radiography, and materials processing.

  3. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    SciTech Connect

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.

    1996-02-01

    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  4. Flexible and fragmentable tandem photosensitive nanocrystal skins

    NASA Astrophysics Data System (ADS)

    Akhavan, S.; Uran, C.; Bozok, B.; Gungor, K.; Kelestemur, Y.; Lesnyak, V.; Gaponik, N.; Eychmüller, A.; Demir, H. V.

    2016-02-01

    We proposed and demonstrated the first account of large-area, semi-transparent, tandem photosensitive nanocrystal skins (PNSs) constructed on flexible substrates operating on the principle of photogenerated potential buildup, which avoid the need for applying an external bias and circumvent the current-matching limitation between junctions. We successfully fabricated and operated the tandem PNSs composed of single monolayers of colloidal water-soluble CdTe and CdHgTe nanocrystals (NCs) in adjacent junctions on a Kapton polymer tape. Owing to the usage of a single NC layer in each junction, noise generation was significantly reduced while keeping the resulting PNS films considerably transparent. In each junction, photogenerated excitons are dissociated at the interface of the semi-transparent Al electrode and the NC layer, with holes migrating to the contact electrode and electrons trapped in the NCs. As a result, the tandem PNSs lead to an open-circuit photovoltage buildup equal to the sum of those of the two single junctions, exhibiting a total voltage buildup of 128.4 mV at an excitation intensity of 75.8 μW cm-2 at 350 nm. Furthermore, we showed that these flexible PNSs could be bent over 3.5 mm radius of curvature and cut out in arbitrary shapes without damaging the operation of individual parts and without introducing any significant loss in the total sensitivity. These findings indicate that the NC skins are promising as building blocks to make low-cost, flexible, large-area UV/visible sensing platforms with highly efficient full-spectrum conversion.We proposed and demonstrated the first account of large-area, semi-transparent, tandem photosensitive nanocrystal skins (PNSs) constructed on flexible substrates operating on the principle of photogenerated potential buildup, which avoid the need for applying an external bias and circumvent the current-matching limitation between junctions. We successfully fabricated and operated the tandem PNSs composed of

  5. Monolithic tandem solar cell

    DOEpatents

    Wanlass, M.W.

    1994-06-21

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. 9 figs.

  6. Monolithic tandem solar cell

    DOEpatents

    Wanlass, Mark W.

    1991-01-01

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

  7. Flexible and fragmentable tandem photosensitive nanocrystal skins.

    PubMed

    Akhavan, S; Uran, C; Bozok, B; Gungor, K; Kelestemur, Y; Lesnyak, V; Gaponik, N; Eychmüller, A; Demir, H V

    2016-02-18

    We proposed and demonstrated the first account of large-area, semi-transparent, tandem photosensitive nanocrystal skins (PNSs) constructed on flexible substrates operating on the principle of photogenerated potential buildup, which avoid the need for applying an external bias and circumvent the current-matching limitation between junctions. We successfully fabricated and operated the tandem PNSs composed of single monolayers of colloidal water-soluble CdTe and CdHgTe nanocrystals (NCs) in adjacent junctions on a Kapton polymer tape. Owing to the usage of a single NC layer in each junction, noise generation was significantly reduced while keeping the resulting PNS films considerably transparent. In each junction, photogenerated excitons are dissociated at the interface of the semi-transparent Al electrode and the NC layer, with holes migrating to the contact electrode and electrons trapped in the NCs. As a result, the tandem PNSs lead to an open-circuit photovoltage buildup equal to the sum of those of the two single junctions, exhibiting a total voltage buildup of 128.4 mV at an excitation intensity of 75.8 μW cm(-2) at 350 nm. Furthermore, we showed that these flexible PNSs could be bent over 3.5 mm radius of curvature and cut out in arbitrary shapes without damaging the operation of individual parts and without introducing any significant loss in the total sensitivity. These findings indicate that the NC skins are promising as building blocks to make low-cost, flexible, large-area UV/visible sensing platforms with highly efficient full-spectrum conversion. PMID:26498487

  8. Ion Trap Mass Spectrometry

    SciTech Connect

    Eiden, Greg C.

    2005-09-01

    This chapter describes research conducted in a few research groups in the 1990s in which RF quadrupole ion trap mass spectrometers were coupled to a powerful atomic ion source, the inductively coupled plasma used in conventional ICP-MS instruments. Major section titles for this chapter are: RF Quadrupole Ion Traps Features of RF Quadrupole Ion Trap Mass Spectrometers Selective Ion Trapping methods Inductively Coupled Plasma Source Ion Trap Mass Spectrometers

  9. Axisymmetric Tandem Mirrors: Stabilization and Confinement Studies

    SciTech Connect

    Post, R F; Fowler, T K; Bulmer, R; Byers, J; Hua, D; Tung, L

    2004-07-15

    The 'Kinetic Stabilizer' has been proposed as a means of MHD stabilizing an axisymmetric tandem mirror system. The K-S concept is based on theoretical studies by Ryutov, confirmed experimentally in the Gas Dynamic Trap experiment in Novosibirsk. In the K-S beams of ions are directed into the end of an 'expander' region outside the outer mirror of a tandem mirror. These ions, slowed, stagnated, and reflected as they move up the magnetic gradient, produce a low-density stabilizing plasma. At the Lawrence Livermore National Laboratory we have been conducting theoretical and computational studies of the K-S Tandem Mirror. These studies have employed a low-beta code written especially to analyze the beam injection/stabilization process, and a new code SYMTRAN (by Hua and Fowler) that solves the coupled radial and axial particle and energy transport in a K-S TM. Also, a 'legacy' MHD stability code, FLORA, has been upgraded and employed to benchmark the injection/stabilization code and to extend its results to high beta values. The FLORA code studies so far have confirmed the effectiveness of the K-S in stabilizing high-beta (40%) plasmas with stabilizer plasmas the peak pressures of which are several orders of magnitude smaller than those of the confined plasma. Also the SYMTRAN code has shown D-T plasma ignition from alpha particle energy deposition in T-M regimes with strong end plugging. Our studies have confirmed the viability of the K-S-T-M concept with respect to MHD stability and radial and axial confinement. We are continuing these studies in order to optimize the parameters and to examine means for the stabilization of possible residual instability modes, such as drift modes and 'trapped-particle' modes. These modes may in principle be controlled by tailoring the stabilizer plasma distribution and/or the radial potential distribution. In the paper the results to date of our studies are summarized and projected to scope out possible fusion-power versions of the K

  10. Axisymmetric Tandem Mirrors: Stabilization and Confinement Studies

    SciTech Connect

    Post, R.F.; Fowler, T.K.; Bulmer, R.; Byers, J.; Hua, D.; Tung, L.

    2005-01-15

    The 'Kinetic Stabilizer' has been proposed as a means of MHD stabilizing an axisymmetric tandem mirror system. The K-S concept is based on theoretical studies by Ryutov, confirmed experimentally in the Gas Dynamic Trap experiment in Novosibirsk. In the K-S beams of ions are directed into the end of an 'expander' region outside the outer mirror of a tandem mirror. These ions, slowed, stagnated, and reflected as they move up the magnetic gradient, produce a low-density stabilizing plasma.At the Lawrence Livermore National Laboratory we have been conducting theoretical and computational studies of the K-S Tandem Mirror. These studies have employed a low-beta code written especially to analyze the beam injection/stabilization process,and a new code SYMTRAN (by Hua and Fowler)that solves the coupled radial and axial particle and energy transport in a K-S T-M. Also, a 'legacy' MHD stability code, FLORA, has been upgraded and employed to benchmark the injection/stabilization code and to extend its results to high beta values.The FLORA code studies so far have confirmed the effectiveness of the K-S in stabilizing high-beta (40%) plasmas with stabilizer plasmas the peak pressures of which are several orders of magnitude smaller than those of the confined plasma.Also the SYMTRAN code has shown D-T plasma ignition from alpha particle energy deposition in T-M regimes with strong end plugging.Our studies have confirmed the viability of the K-S T-M concept with respect to MHD stability and radial and axial confinement. We are continuing these studies in order to optimize the parameters and to examine means for the stabilization of possible residual instability modes, such as drift modes and 'trapped-particle' modes. These modes may in principle be controlled by tailoring the stabilizer plasma distribution and/or the radial potential distribution.In the paper the results to date of our studies are summarized and projected to scope out possible fusion-power versions of the K-S T-M.

  11. Fueling of tandem mirror reactors

    SciTech Connect

    Gorker, G.E.; Logan, B.G.

    1985-01-01

    This paper summarizes the fueling requirements for experimental and demonstration tandem mirror reactors (TMRs), reviews the status of conventional pellet injectors, and identifies some candidate accelerators that may be needed for fueling tandem mirror reactors. Characteristics and limitations of three types of accelerators are described; neutral beam injectors, electromagnetic rail guns, and laser beam drivers. Based on these characteristics and limitations, a computer module was developed for the Tandem Mirror Reactor Systems Code (TMRSC) to select the pellet injector/accelerator combination which most nearly satisfies the fueling requirements for a given machine design.

  12. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Tandem-switched transport and tandem charge. 69... SERVICES (CONTINUED) ACCESS CHARGES Computation of Charges § 69.111 Tandem-switched transport and tandem...-switched transport shall consist of two rate elements, a transmission charge and a tandem switching...

  13. 47 CFR 69.111 - Tandem-switched transport and tandem charge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Tandem-switched transport and tandem charge. 69... SERVICES (CONTINUED) ACCESS CHARGES Computation of Charges § 69.111 Tandem-switched transport and tandem...-switched transport shall consist of two rate elements, a transmission charge and a tandem switching...

  14. Sequence alignment with tandem duplication

    SciTech Connect

    Benson, G.

    1997-12-01

    Algorithm development for comparing and aligning biological sequences has, until recently, been based on the SI model of mutational events which assumes that modification of sequences proceeds through any of the operations of substitution, insertion or deletion (the latter two collectively termed indels). While this model has worked farily well, it has long been apparent that other mutational events occur. In this paper, we introduce a new model, the DSI model which includes another common mutational event, tandem duplication. Tandem duplication produces tandem repeats which are common in DNA, making up perhaps 10% of the human genome. They are responsible for some human diseases and may serve a multitude of functions in DNA regulation and evolution. Using the DSI model, we develop new exact and heuristic algorithms for comparing and aligning DNA sequences when they contain tandem repeats. 30 refs., 3 figs.

  15. Sorption vacuum trap

    NASA Technical Reports Server (NTRS)

    Barrington, A. E.; Caruso, A. J.

    1970-01-01

    Modified sorption trap for use in high vacuum systems contains provisions for online regeneration of sorbent material. Trap is so constructed that it has a number of encapsulated resistance heaters and a valving and pumping device for removing gases from heated sorbing material. Excessive downtime is eliminated with this trap.

  16. Ion trap simulation tools.

    SciTech Connect

    Hamlet, Benjamin Roger

    2009-02-01

    Ion traps present a potential architecture for future quantum computers. These computers are of interest due to their increased power over classical computers stemming from the superposition of states and the resulting capability to simultaneously perform many computations. This paper describes a software application used to prepare and visualize simulations of trapping and maneuvering ions in ion traps.

  17. Tandem Cylinder Noise Predictions

    NASA Technical Reports Server (NTRS)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  18. Trap style influences wild pig behavior and trapping success

    USGS Publications Warehouse

    Williams, B.L.; Holtfreter, R.W.; Ditchkoff, S.S.; Grand, J.B.

    2011-01-01

    Despite the efforts of many natural resource professionals, wild pig (Sus scrofa) populations are expanding in many areas of the world. Although many creative techniques for controlling pig populations are being explored, trapping has been and still is themost commonly usedmethod of population control formany public and private land managers. We conducted an observational study to examine the efficiency of 2 frequently used trap styles: a small, portable box-style trap and a larger, semi-permanent, corral-style trap.We used game cameras to examine patterns of trap entry by wild pigs around each style of trap, and we conducted a trapping session to compare trapping success between trap styles. Adult female and juvenile wild pigs entered both styles of trap more readily than did adult males, and adult males seemed particularly averse to entering box traps. Less than 10% of adult male visits to box traps resulted in entries, easily the least percentage of any class at any style of trap. Adult females entered corral traps approximately 2.2 times more often per visit than box traps and re-entered corral traps >2 times more frequently. Juveniles entered and reentered both box and corral traps at similar rates. Overall (all-class) entry-per-visit rates at corral traps (0.71) were nearly double that of box traps (0.37). Subsequent trapping data supported these preliminary entry data; the capture rate for corral traps was >4 times that of box traps. Our data suggest that corral traps are temporally and economically superior to box traps with respect to efficiency; that is, corral traps effectively trap more pigs per trap night at a lower cost per pig than do box traps. ?? 2011 The Wildlife Society.

  19. Ecological and evolutionary traps

    USGS Publications Warehouse

    Schlaepfer, Martin A.; Runge, M.C.; Sherman, P.W.

    2002-01-01

    Organisms often rely on environmental cues to make behavioral and life-history decisions. However, in environments that have been altered suddenly by humans, formerly reliable cues might no longer be associated with adaptive outcomes. In such cases, organisms can become 'trapped' by their evolutionary responses to the cues and experience reduced survival or reproduction. Ecological traps occur when organisms make poor habitat choices based on cues that correlated formerly with habitat quality. Ecological traps are part of a broader phenomenon, evolutionary traps, involving a dissociation between cues that organisms use to make any behavioral or life-history decision and outcomes normally associated with that decision. A trap can lead to extinction if a population falls below a critical size threshold before adaptation to the novel environment occurs. Conservation and management protocols must be designed in light of, rather than in spite of, the behavioral mechanisms and evolutionary history of populations and species to avoid 'trapping' them.

  20. Microfabricated ion trap array

    DOEpatents

    Blain, Matthew G.; Fleming, James G.

    2006-12-26

    A microfabricated ion trap array, comprising a plurality of ion traps having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale ion traps to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The reduced electrode voltage enables integration of the microfabricated ion trap array with on-chip circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of the microfabricated ion trap array can be realized in truly field portable, handheld microanalysis systems.

  1. Resolution of nuclear ground and isomeric states by a Penning trap mass spectrometer

    SciTech Connect

    Bollen, G.; Kluge, H.; Koenig, M.; Otto, T.; Savard, G.; Stolzenberg, H. ); Moore, R.B.; Rouleau, G. ); Audi, G. )

    1992-12-01

    Ground and isomeric states of a nucleus have been resolved for the first time by mass spectrometry. Measurements on [sup 78]Rb[sup [ital m],][ital g] and [sup 84]Rb[sup [ital m],][ital g] were performed using a tandem Penning trap mass spectrometer on-line with the isotope separator ISOLDE/CERN. The effects of ion-ion interaction were investigated for two ion species differing in mass and stored simultaneously in the trap.

  2. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  3. Trapped particle stability for the kinetic stabilizer

    NASA Astrophysics Data System (ADS)

    Berk, H. L.; Pratt, J.

    2011-08-01

    A kinetically stabilized axially symmetric tandem mirror (KSTM) uses the momentum flux of low-energy, unconfined particles that sample only the outer end-regions of the mirror plugs, where large favourable field-line curvature exists. The window of operation is determined for achieving magnetohydrodynamic (MHD) stability with tolerable energy drain from the kinetic stabilizer. Then MHD stable systems are analysed for stability of the trapped particle mode. This mode is characterized by the detachment of the central-cell plasma from the kinetic-stabilizer region without inducing field-line bending. Stability of the trapped particle mode is sensitive to the electron connection between the stabilizer and the end plug. It is found that the stability condition for the trapped particle mode is more constraining than the stability condition for the MHD mode, and it is challenging to satisfy the required power constraint. Furthermore, a severe power drain may arise from the necessary connection of low-energy electrons in the kinetic stabilizer to the central region.

  4. Liquid metal cold trap

    DOEpatents

    Hundal, Rolv

    1976-01-01

    A cold trap assembly for removing impurities from a liquid metal being provided with a hole between the incoming impure liquid metal and purified outgoing liquid metal which acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly.

  5. Deuterium trapping in tungsten

    NASA Astrophysics Data System (ADS)

    Poon, Michael

    Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

  6. Optical Trapping of Nanoparticles

    PubMed Central

    Bergeron, Jarrah; Zehtabi-Oskuie, Ana; Ghaffari, Saeedeh; Pang, Yuanjie; Gordon, Reuven

    2013-01-01

    Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3. A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure. The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm

  7. Optical trapping of nanoparticles.

    PubMed

    Bergeron, Jarrah; Zehtabi-Oskuie, Ana; Ghaffari, Saeedeh; Pang, Yuanjie; Gordon, Reuven

    2013-01-01

    Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec, which has serious implications for biological matter. A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure. The double-nanohole structure has been shown to give a strong local field enhancement. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres and 3.4 nm hydrodynamic radius

  8. Ion Sponge: A 3-Dimentional Array of Quadrupole Ion Traps for Trapping and Mass-Selectively Processing Ions in Gas Phase

    PubMed Central

    2015-01-01

    In this study, the concept of ion sponge has been explored for developing 3D arrays of large numbers of ion traps but with simple configurations. An ion sponge device with 484 trapping units in a volume of 10 × 10 × 3.2 cm has been constructed by simply stacking 9 meshes together. A single rf was used for trapping ions and mass-selective ion processing. The ion sponge provides a large trapping capacity and is highly transparent for transfer of ions, neutrals, and photons for gas phase ion processing. Multiple layers of quadrupole ion traps, with 121 trapping units in each layer, can operate as a single device for MS or MS/MS analysis, or as a series of mass-selective trapping devices with interlayer ion transfers facilitated by AC and DC voltages. Automatic sorting of ions to different trapping layers based on their mass-to-charge (m/z) ratios was achieved with traps of different sizes. Tandem-in-space MS/MS has also been demonstrated with precursor ions and fragment ions trapped in separate locations. PMID:24758328

  9. Nonlinear integrable ion traps

    SciTech Connect

    Nagaitsev, S.; Danilov, V.; /SNS Project, Oak Ridge

    2011-10-01

    Quadrupole ion traps can be transformed into nonlinear traps with integrable motion by adding special electrostatic potentials. This can be done with both stationary potentials (electrostatic plus a uniform magnetic field) and with time-dependent electric potentials. These potentials are chosen such that the single particle Hamilton-Jacobi equations of motion are separable in some coordinate systems. The electrostatic potentials have several free adjustable parameters allowing for a quadrupole trap to be transformed into, for example, a double-well or a toroidal-well system. The particle motion remains regular, non-chaotic, integrable in quadratures, and stable for a wide range of parameters. We present two examples of how to realize such a system in case of a time-independent (the Penning trap) as well as a time-dependent (the Paul trap) configuration.

  10. Optically programmable excitonic traps

    PubMed Central

    Alloing, Mathieu; Lemaître, Aristide; Galopin, Elisabeth; Dubin, François

    2013-01-01

    With atomic systems, optically programmed trapping potentials have led to remarkable progress in quantum optics and quantum information science. Programmable trapping potentials could have a similar impact on studies of semiconductor quasi-particles, particularly excitons. However, engineering such potentials inside a semiconductor heterostructure remains an outstanding challenge and optical techniques have not yet achieved a high degree of control. Here, we synthesize optically programmable trapping potentials for indirect excitons of bilayer heterostructures. Our approach relies on the injection and spatial patterning of charges trapped in a field-effect device. We thereby imprint in-situ and on-demand electrostatic traps into which we optically inject cold and dense ensembles of excitons. This technique creates new opportunities to improve state-of-the-art technologies for the study of collective quantum behavior of excitons and also for the functionalisation of emerging exciton-based opto-electronic circuits. PMID:23546532

  11. Optical trapping and binding

    NASA Astrophysics Data System (ADS)

    Bowman, Richard W.; Padgett, Miles J.

    2013-02-01

    The phenomenon of light's momentum was first observed in the laboratory at the beginning of the twentieth century, and its potential for manipulating microscopic particles was demonstrated by Ashkin some 70 years later. Since that initial demonstration, and the seminal 1986 paper where a single-beam gradient-force trap was realized, optical trapping has been exploited as both a rich example of physical phenomena and a powerful tool for sensitive measurement. This review outlines the underlying theory of optical traps, and explores many of the physical observations that have been made in such systems. These phenomena include ‘optical binding’, where trapped objects interact with one another through the trapping light field. We also discuss a number of the applications of ‘optical tweezers’ across the physical and life sciences, as well as covering some of the issues involved in constructing and using such a tool.

  12. 10 K Ring Electrode Trap—Tandem Mass Spectrometer for Infrared Spectroscopy of Mass Selected Ions

    NASA Astrophysics Data System (ADS)

    Goebbert, Daniel J.; Meijer, Gerard; Asmis, Knut R.

    2009-03-01

    A novel instrumental setup for measuring infrared photodissociation spectra of buffer gas cooled, mass-selected ions is described and tested. It combines a cryogenically cooled, linear radio frequency ion trap with a tandem mass spectrometer, optimally coupling continuous ion sources to pulsed laser experiments. The use of six independently adjustable DC potentials superimposed over the trapping radio frequency field provides control over the ion distribution within, as well as the kinetic energy distribution of the ions extracted from the ion trap. The scheme allows focusing the ions in space and time, such that they can be optimally irradiated by a pulsed, widely tunable infrared photodissociation laser. Ion intensities are monitored with a time-of-flight mass spectrometer mounted orthogonally to the ion trap axis.

  13. Trace analysis of explosives in seawater using solid-phase microextraction and gas chromatography/ion trap mass spectrometry

    SciTech Connect

    Barshick, S.A.; Griest, W.H.

    1998-07-15

    Complex matrices typically cannot be analyzed directly to obtain the selectivity and sensitivity required for most trace analysis applications. To circumvent this problem, solid-phase microextraction (SPME) techniques were used to preconcentrate analytes selectively prior to gas chromatographic/ion trap mass spectrometric analysis. This approach was applied to the trace analysis of explosives and their metabolites in seawater. The choice of SPME sorbent phase was shown to be important especially for the amino metabolites of trinitrotoluene (TNT) and RDX, which were extracted better on polar phases. Although equilibration times were quite lengthy, on the order of 30 min or greater, a sampling time of only 10 min was shown to be sufficient for achieving low part-per-billion (ppb) to part-per-trillion (ppt) detection limits for TNT and the amino metabolites in real seawater samples. While SPME was ideal for rapid screening of explosives in seawater samples, methods for improving the reproducibility and accuracy of quantification are still being investigated.

  14. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    SciTech Connect

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-08-29

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented.

  15. Trapping deuterium atoms

    SciTech Connect

    Wiederkehr, A. W.; Hogan, S. D.; Lambillotte, B.; Andrist, M.; Schmutz, H.; Agner, J.; Salathe, Y.; Merkt, F.

    2010-02-15

    Cold deuterium atoms in a supersonic beam have been decelerated from an initial velocity of 475 m/s to zero velocity in the laboratory frame using a 24-stage Zeeman decelerator. The atoms have been loaded in a magnetic quadrupole trap at a temperature of {approx}100 mK and an initial density of {approx}10{sup 6} cm{sup -3}. Efficient deceleration was achieved by pulsing the magnetic fields in the decelerator solenoids using irregular sequences of phase angles. Trap loading was optimized by monitoring and suppressing the observed reflection of the atoms by the field gradient of the back solenoid of the trap.

  16. Stratigraphic traps 2

    SciTech Connect

    Not Available

    1991-01-01

    This volume contains studies of fields with traps that are mainly stratigraphic in nature. Structure plays a role in the traps of several fields, but overall, it is clear that the main trapping features with the group of fields in this volume are stratigraphic. The first six fields in this volume, Alabama Ferry, Rospo Mare, Walker Creek, Bindley, Lexington, and Newburg/South Westhope, have carbonate reservoirs. The latter two of these, Lexington and Newburg/South Westhope, also have sandstone reservoirs. The remaining fields, East Texas, East Clinton, Stockholm Southwest, Sorrento, Port Acres, and Lagoa Parda, have only sandstone reservoirs.

  17. The nature of the TRAP-Anti-TRAP complex.

    PubMed

    Watanabe, Masahiro; Heddle, Jonathan G; Kikuchi, Kenichi; Unzai, Satoru; Akashi, Satoko; Park, Sam-Yong; Tame, Jeremy R H

    2009-02-17

    Tryptophan biosynthesis is subject to exquisite control in species of Bacillus and has become one of the best-studied model systems in gene regulation. The protein TRAP (trp RNA-binding attenuation protein) predominantly forms a ring-shaped 11-mer, which binds cognate RNA in the presence of tryptophan to suppress expression of the trp operon. TRAP is itself regulated by the protein Anti-TRAP, which binds to TRAP and prevents RNA binding. To date, the nature of this interaction has proved elusive. Here, we describe mass spectrometry and analytical centrifugation studies of the complex, and 2 crystal structures of the TRAP-Anti-TRAP complex. These crystal structures, both refined to 3.2-A resolution, show that Anti-TRAP binds to TRAP as a trimer, sterically blocking RNA binding. Mass spectrometry shows that 11-mer TRAP may bind up to 5 AT trimers, and an artificial 12-mer TRAP may bind 6. Both forms of TRAP make the same interactions with Anti-TRAP. Crystallization of wild-type TRAP with Anti-TRAP selectively pulls the 12-mer TRAP form out of solution, so the crystal structure of wild-type TRAP-Anti-TRAP complex reflects a minor species from a mixed population. PMID:19164760

  18. Nanocrystal assembly for tandem catalysis

    DOEpatents

    Yang, Peidong; Somorjai, Gabor; Yamada, Yusuke; Tsung, Chia-Kuang; Huang, Wenyu

    2014-10-14

    The present invention provides a nanocrystal tandem catalyst comprising at least two metal-metal oxide interfaces for the catalysis of sequential reactions. One embodiment utilizes a nanocrystal bilayer structure formed by assembling sub-10 nm platinum and cerium oxide nanocube monolayers on a silica substrate. The two distinct metal-metal oxide interfaces, CeO.sub.2--Pt and Pt--SiO.sub.2, can be used to catalyze two distinct sequential reactions. The CeO.sub.2--Pt interface catalyzed methanol decomposition to produce CO and H.sub.2, which were then subsequently used for ethylene hydroformylation catalyzed by the nearby Pt--SiO.sub.2 interface. Consequently, propanal was selectively produced on this nanocrystal bilayer tandem catalyst.

  19. Optically trapped fluorescent nanodiamonds

    NASA Astrophysics Data System (ADS)

    Horowitz, Viva R.; Alemán, Benjamin J.; Christle, David; Cleland, Andrew N.; Awschalom, David D.

    2012-02-01

    The electronic spin state of the nitrogen-vacancy (NV) center in diamond has gained considerable interest because it can be optically initialized, coherently manipulated, and optically read out at room temperature. In addition, nanoparticle diamonds containing NV centers can be integrated with biological and microfluidic systems. We have constructed and characterized an optical tweezers apparatus to trap fluorescent nanodiamonds in a fluid and measure their fluorescence. Particles are held and moved in three dimensions using an infrared trapping laser. Fluorescent detection of these optically trapped nanodiamonds enables us to observe nanoparticle dynamics and to measure electron spin resonance of NV centers. We will discuss applications using the electron spin resonance of trapped NV centers in nanodiamonds for magnetic field imaging in fluidic environments.

  20. Steam trap monitor

    DOEpatents

    Ryan, M.J.

    1987-05-04

    A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (a hot finger) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellow in providing an indication of total energy (steam + condensate) of the system. Processing means coupled to and responsive to outputs from the hot and cold fingers subtracts the former from the latter to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning. 2 figs.

  1. Trapping and Probing Antihydrogen

    SciTech Connect

    Wurtele, Jonathan

    2013-03-27

    Precision spectroscopy of antihydrogen is a promising path to sensitive tests of CPT symmetry. The most direct route to achieve this goal is to create and probe antihydrogen in a magnetic minimum trap. Antihydrogen has been synthesized and trapped for 1000s at CERN by the ALPHA Collaboration. Some of the challenges associated with achieving these milestones will be discussed, including mixing cryogenic positron and antiproton plasmas to synthesize antihydrogen with kinetic energy less than the trap potential of .5K. Recent experiments in which hyperfine transitions were resonantly induced with microwaves will be presented. The opportunity for gravitational measurements in traps based on detailed studies of antihydrogen dynamics will be described. The talk will conclude with a discussion future antihydrogen research that will use a new experimental apparatus, ALPHA-I.

  2. Structural traps 5

    SciTech Connect

    Foster, N.H.; Beaumont, E.A.

    1991-01-01

    This book contains studies of oil and gas fields that are mainly structural in nature. Stratigraphy controls the extend of the reservoir in the traps of several fields, but overall, the main trapping features within the group of fields in this volume are structural. Fields covered in this volume include: Endicott Field, Point Arguello Field, West Puerto Chiquito Field, Dukhan Field, Sendji Field, Ruston Field, Raudhatain Field, Hassi Messaoud Field, Snapper Field, Tirrawarra Field, and Sacha Field.

  3. Electrospray Ionization Tandem Mass Spectrometry of Ammonium Cationized Polyethers

    NASA Astrophysics Data System (ADS)

    Nasioudis, Andreas; Heeren, Ron M. A.; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F.

    2011-05-01

    Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers.

  4. "Nanocrystal bilayer for tandem catalysis"

    SciTech Connect

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  5. Optical trapping of nanoshells

    NASA Astrophysics Data System (ADS)

    Hester, Brooke C.; Crawford, Alice; Kishore, Rani B.; Helmerson, Kristian; Halas, Naomi J.; Levin, Carly

    2007-09-01

    We investigate near-resonant trapping of Rayleigh particles in optical tweezers. Although optical forces due to a near-resonant laser beam have been extensively studied for atoms, the situation for larger particles is that the laser wavelength is far from any absorption resonance. Theory predicts, however, that the trapping force exerted on a Rayleigh particle is enhanced, and may be three to fifty times larger for frequencies near resonance than for frequencies far off resonance. The ability to selectively trap only particles with a given absorption peak may have many practical applications. In order to investigate near-resonant trapping we are using nanoshells, particles with a dielectric core and metallic coating that can exhibit plasmon resonances. The resonances of the nanoshells can be tuned by adjusting the ratio of the radius of the dielectric core, r I, to the overall radius, r II, which includes the thickness of the metallic coating. Our nanoshells, fabricated at Rice University, consist of a silica core with a gold coating. Using back focal plane detection, we measure the trap stiffness of a single focus optical trap (optical tweezers), from a diode laser at 853 nm for nanoshells with several different r I/r II ratios.

  6. Microfabricated cylindrical ion trap

    DOEpatents

    Blain, Matthew G.

    2005-03-22

    A microscale cylindrical ion trap, having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale cylindrical ion trap to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The microscale CIT has a reduced ion mean free path, allowing operation at higher pressures with less expensive and less bulky vacuum pumping system, and with lower battery power than conventional- and miniature-sized ion traps. The reduced electrode voltage enables integration of the microscale cylindrical ion trap with on-chip integrated circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of microscale cylindrical ion traps can be realized in truly field portable, handheld microanalysis systems.

  7. Short Tandem Repeat DNA Internet Database

    National Institute of Standards and Technology Data Gateway

    SRD 130 Short Tandem Repeat DNA Internet Database (Web, free access)   Short Tandem Repeat DNA Internet Database is intended to benefit research and application of short tandem repeat DNA markers for human identity testing. Facts and sequence information on each STR system, population data, commonly used multiplex STR systems, PCR primers and conditions, and a review of various technologies for analysis of STR alleles have been included.

  8. Trapping Methylglyoxal by Genistein and Its Metabolites in Mice.

    PubMed

    Wang, Pei; Chen, Huadong; Sang, Shengmin

    2016-03-21

    Increasing evidence supports dicarbonyl stress such as methylglyoxal (MGO) as one of the major pathogenic links between hyperglycemia and diabetic complications. In vitro studies have shown that dietary flavonoids can inhibit the formation of advanced glycation end products (AGEs) by trapping MGO. However, whether flavonoids can trap MGO in vivo and whether biotransformation limits the trapping capacity of flavonoids remain virtually unknown. In this study, we investigated whether genistein (GEN), the major soy isoflavone, could trap MGO in mice by promoting the formation of MGO adducts of GEN and its metabolites. Two different mouse studies were conducted. In the acute study, a single dose of MGO and GEN were administered to mice via oral gavage. In the chronic study, MGO was given to mice in drinking water for 1 month and then GEN was given to mice for 4 consecutive days via oral gavage. Two mono-MGO adducts of GEN and six mono-MGO adducts of GEN phase I and microbial metabolites were identified in mouse urine samples from these studies using liquid chromatography/electrospray ionization tandem mass spectrometry. The structures of these MGO adducts were confirmed by analyzing their MS(n) (n = 1-4) spectra as well as by comparing them with the tandem mass spectra of authentic standards. All of the MGO adducts presented in their phase II conjugated forms in mouse urine samples in the acute and chronic studies. To our knowledge, this is the first in vivo evidence to demonstrate the trapping efficacy of GEN in mice and to show that the metabolites of GEN remain bioactive. PMID:26881724

  9. The characterization of tandem and corrugated wings

    NASA Astrophysics Data System (ADS)

    Lian, Yongsheng; Broering, Timothy; Hord, Kyle; Prater, Russell

    2014-02-01

    Dragonfly wings have two distinct features: a tandem configuration and wing corrugation. Both features have been extensively studied with the aim to understand the superior flight performance of dragonflies. In this paper we review recent development of tandem and corrugated wing aerodynamics. With regards to the tandem configuration, this review will focus on wing/wing and wing/vortex interactions at different flapping modes and wing spacing. In addition, the aerodynamics of tandem wings under gusty conditions will be reviewed and compared with isolated wings to demonstrate the gust resistance characteristics of flapping wings. Regarding corrugated wings, we review their structural and aerodynamic characteristics.

  10. Recent Activities at Tokai Tandem Accelerator

    SciTech Connect

    Ishii, Tetsuro

    2010-05-12

    Recent activities at the JAEA-Tokai tandem accelerator facility are presented. The terminal voltage of the tandem accelerator reached 19.1 MV by replacing acceleration tubes. The multi-charged positive-ion injector was installed in the terminal of the tandem accelerator, supplying high-current noble-gas ions. A superconducting cavity for low-velocity ions was developed. Radioactive nuclear beams of {sup 8,9}Li and fission products, produced by the tandem accelerator and separated by the ISOL, were supplied with experiment. Recent results of nuclear physics experiments are reported.

  11. Detecting long tandem duplications in genomic sequences

    PubMed Central

    2012-01-01

    Background Detecting duplication segments within completely sequenced genomes provides valuable information to address genome evolution and in particular the important question of the emergence of novel functions. The usual approach to gene duplication detection, based on all-pairs protein gene comparisons, provides only a restricted view of duplication. Results In this paper, we introduce ReD Tandem, a software using a flow based chaining algorithm targeted at detecting tandem duplication arrays of moderate to longer length regions, with possibly locally weak similarities, directly at the DNA level. On the A. thaliana genome, using a reference set of tandem duplicated genes built using TAIR,a we show that ReD Tandem is able to predict a large fraction of recently duplicated genes (dS < 1) and that it is also able to predict tandem duplications involving non coding elements such as pseudo-genes or RNA genes. Conclusions ReD Tandem allows to identify large tandem duplications without any annotation, leading to agnostic identification of tandem duplications. This approach nicely complements the usual protein gene based which ignores duplications involving non coding regions. It is however inherently restricted to relatively recent duplications. By recovering otherwise ignored events, ReD Tandem gives a more comprehensive view of existing evolutionary processes and may also allow to improve existing annotations. PMID:22568762

  12. Switching Oxide Traps

    NASA Technical Reports Server (NTRS)

    Oldham, Timothy R.

    2003-01-01

    We consider radiation-induced charge trapping in SiO2 dielectric layers, primarily from the point of view of CMOS devices. However, SiO2 insulators are used in many other ways, and the same defects occur in other contexts. The key studies, which determined the nature of the oxide charge traps, were done primarily on gate oxides in CMOS devices, because that was the main radiation problem in CMOS at one time. There are two major reviews of radiation-induced oxide charge trapping already in the literature, which discuss the subject in far greater detail than is possible here. The first of these was by McLean et al. in 1989, and the second, ten years later, was intended as an update, because of additional, new work that had been reported. Basically, the picture that has emerged is that ionizing radiation creates electron-hole pairs in the oxide, and the electrons have much higher mobility than the holes. Therefore, the electrons are swept out of the oxide very rapidly by any field that is present, leaving behind any holes that escape the initial recombination process. These holes then undergo a polaron hopping transport toward the Si/SiO2 interface (under positive bias). Near the interface, some fraction of them fall into deep, relatively stable, long-lived hole traps. The nature and annealing behavior of these hole traps is the main focus of this paper.

  13. Calculation of density profiles in tandem mirrors fueled by pellets

    SciTech Connect

    Campbell, R.B.; Gilmore, J.M.

    1983-12-02

    We have modified the LLNL radial transport code TMT to model reactor regime plasmas, fueled by pellets. The source profiles arising from pellet fueling are obtained from existing pellet ablation models. Because inward radial diffusion due to inverted profiles must compete with trapping of central cell ions in the transition region for tandem mirrors, pellets must penetrate fairly far into the plasma. In fact, based on our radial calculations, a pellet with a velocity of 10 km/sec cannot sustain the central flux tubes; a velocity more like 100 km/sec will be necessary. We also find that the central cell radial diffusion must exceed classical by about a factor of 100.

  14. Ion-molecule adduct formation in tandem mass spectrometry.

    PubMed

    Alechaga, Élida; Moyano, Encarnación; Galceran, Maria Teresa

    2016-02-01

    Nowadays most LC-MS methods rely on tandem mass spectrometry not only for quantitation and confirmation of compounds by multiple reaction monitoring (MRM), but also for the identification of unknowns from their product ion spectra. However, gas-phase reactions between charged and neutral species inside the mass analyzer can occur, yielding product ions at m/z values higher than that of the precursor ion, or at m/z values difficult to explain by logical losses, which complicate mass spectral interpretation. In this work, the formation of adduct ions in the mass analyzer was studied using several mass spectrometers with different mass analyzers (ion trap, triple quadrupole, and quadrupole-Orbitrap). Heterocyclic amines (AαC, MeAαC, Trp-P-1, and Trp-P-2), photo-initiators (BP and THBP), and pharmaceuticals (phenacetin and levamisole) were selected as model compounds and infused in LCQ Classic, TSQ Quantum Ultra AM, and Q-Exactive Orbitrap (ThermoFisher Scientific) mass spectrometers using electrospray as ionization method. The generation of ion-molecule adducts depended on the compound and also on the instrument employed. Adducts with neutral organic solvents (methanol and acetonitrile) were only observed in the ion trap instrument (LCQ Classic), because of the ionization source on-axis configuration and the lack of gas-phase barriers, which allowed inertial entrance of the neutrals into the analyzer. Adduct formation (only with water) in the triple quadrupole instruments was less abundant than in the ion trap and quadrupole-Orbitrap mass spectrometers, because of the lower residence time of the reactive product ions in the mass analyzer. The moisture level of the CID and/or damper gas had a great effect in beam-like mass analyzers such as triple quadrupole, but not in trap-like mass analyzers, probably because of the long residence time that allowed adduct formation even with very low concentrations of water inside the mass spectrometer. PMID:26700446

  15. Thermoelectrically cooled water trap

    DOEpatents

    Micheels, Ronald H.

    2006-02-21

    A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

  16. Tandem mirror technology demonstration facility

    SciTech Connect

    Not Available

    1983-10-01

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M/sup 2/) on an 8-m/sup 2/ test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m/sup 2/ and give the necessary experience for successful operation of an ETR.

  17. Improved monolithic tandem solar cell

    SciTech Connect

    Wanlass, M.W.

    1991-04-23

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surf ace of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.

  18. Asymmetric ion trap

    DOEpatents

    Barlow, Stephan E.; Alexander, Michael L.; Follansbee, James C.

    1997-01-01

    An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.

  19. Ion trap device

    DOEpatents

    Ibrahim, Yehia M.; Smith, Richard D.

    2016-01-26

    An ion trap device is disclosed. The device includes a series of electrodes that define an ion flow path. A radio frequency (RF) field is applied to the series of electrodes such that each electrode is phase shifted approximately 180 degrees from an adjacent electrode. A DC voltage is superimposed with the RF field to create a DC gradient to drive ions in the direction of the gradient. A second RF field or DC voltage is applied to selectively trap and release the ions from the device. Further, the device may be gridless and utilized at high pressure.

  20. Tandem transcription and translation regulatory sensing of uncharged tryptophan tRNA.

    PubMed

    Chen, Guangnan; Yanofsky, Charles

    2003-07-11

    The Bacillus subtilis AT (anti-TRAP) protein inhibits the regulatory protein TRAP (trp RNA-binding attenuation protein), thereby eliminating transcription termination in the leader region of the trp operon. Transcription of the AT operon is activated by uncharged tryptophan transfer RNA (tRNATrp). Here we show that translation of AT also is regulated by uncharged tRNATrp. A 10-residue coding region containing three consecutive tryptophan codons is located immediately preceding the AT structural gene. Completion of translation of this coding region inhibits AT synthesis, whereas incomplete translation increases AT production. Tandem sensing of uncharged tRNATrp therefore regulates synthesis of AT, which in turn regulates TRAP's ability to inhibit trp operon expression. PMID:12855807

  1. HWVP Iodine Trap Evaluation

    SciTech Connect

    Burger, Leland L.; Scheele, Randall D.

    2004-09-24

    This report details our assessment of the chemistry of the planned Hanford Waste Vitrification Plant (HWVP) off-gas system and its impact on the applicability of known iodine removal and control methods. To predict the gaseous species in the off-gas system, we completed thermodynamic calculations to determine theoretical equilibrium concentrations of the various potential chemical species. In addition, we found that HWVP pilot-plant experiments were generally consistent with the known chemistry of the individual elements present in the off gas. Of the known trapping techniques for radioiodine, caustic scrubbing and silver-containing sorbents are, in our opinion, the most attractive methods to reduce the iodine concentration in the HWVP melter off gas (MOG) after it has passed through the high-efficiency particulate air (HEPA) filter. These two methods were selected because they (1) have demonstrated retention factors (RFs), ratio of amount in and amount out, of 10 to 1000, which would be sufficient to reduce the iodine concentration in the MOG to below regulatory limits; (2) are simple to apply; (3) are resistant to oxidizing gases such as NOx; (4) do not employ highly hazardous or highly corrosive agents; (5) require containment vessels constructed or common materials; (6) have received extensive laboratory development; (7) and the radioactive wastes produced should be easy to handle. On the basis of iodine trapping efficiency, simplicity of operation, and waste management, silver sorbents are superior to caustic scrubbing, and, or these sorbents, we prefer the silver zeolites. No method has been fully demonstrated, from laboratory-scale through pilot-plant testing, to be an effective iodine trap at the low iodine concentration (2 x 10-11 mol I/L) expected in the MOG of the HWVP in the presence of the other gaseous off gas components. In terms of compatibility of the trapping technology with the components in the MOG, there is some question about the resistance of

  2. Measurement of Trap Length for an Optical Trap

    NASA Technical Reports Server (NTRS)

    Wrbanek, Susan Y.

    2009-01-01

    The trap length along the beam axis for an optical trap formed with an upright, oil-immersion microscope was measured. The goals for this effort were twofold. It was deemed useful to understand the depth to which an optical trap can reach for purposes of developing a tool to assist in the fabrication of miniature devices. Additionally, it was desired to know whether the measured trap length favored one or the other of two competing theories to model an optical trap. The approach was to trap a microsphere of known size and mass and raise it from its initial trap position. The microsphere was then dropped by blocking the laser beam for a pre-determined amount of time. Dropping the microsphere in a free-fall mode from various heights relative to the coverslip provides an estimate of how the trapping length changes with depth in water in a sample chamber on a microscope slide. While it was not possible to measure the trap length with sufficient precision to support any particular theory of optical trap formation, it was possible to find regions where the presence of physical boundaries influenced optical traps, and determine that the trap length, for the apparatus studied, is between 6 and 7 m. These results allow more precise control using optical micromanipulation to assemble miniature devices by providing information about the distance over which an optical trap is effective.

  3. Tandem junction amorphous silicon solar cells

    DOEpatents

    Hanak, Joseph J.

    1981-01-01

    An amorphous silicon solar cell has an active body with two or a series of layers of hydrogenated amorphous silicon arranged in a tandem stacked configuration with one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon arranged in tandem configuration can have the same bandgap or differing bandgaps.

  4. 33 CFR 401.41 - Tandem lockage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Tandem lockage. 401.41 Section 401.41 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Seaway Navigation § 401.41 Tandem lockage. Where two...

  5. Practical axial optical trapping

    PubMed Central

    Mack, A. H.; Schlingman, D. J.; Regan, L.; Mochrie, S. G. J.

    2012-01-01

    We describe a new method for calibrating optical trapping measurements in which tension is applied in the direction of the laser beam to a molecule tethered between a surface and an optically trapped bead. Specifically, we present a generally-applicable procedure for converting from the measured scattering intensity and the measured stage displacement to applied tension and bead-coverslip separation, using measurements of the light intensity scattered from an untethered, trapped bead. Our calibration accounts for a number of effects, including aberrations and the interference of forward-reflected bead-scattered light with the trapping beam. To demonstrate the accuracy of our method, we show measurements of the DNA force-versus-extension relation using a range of laser intensities, and show that these measurements match the expected extensible wormlike-chain (WLC) behavior. Finally, we also demonstrate a force-clamp, in which the tension in a tether is held fixed while the extension varies as a result of molecular events. PMID:23126750

  6. Steam trap monitor

    DOEpatents

    Ryan, Michael J.

    1988-01-01

    A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (the combination of a hot finger and thermocouple well) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellows in providing an indication of total energy (steam+condensate) of the system. Processing means coupled to and responsive to outputs from the thermocouple well hot and cold fingers subtracts the condensate energy as measured by the hot finger and thermocouple well from the total energy as measured by the cold finger to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning.

  7. Rotating Saddle Paul Trap.

    ERIC Educational Resources Information Center

    Rueckner, Wolfgang; And Others

    1995-01-01

    Describes a demonstration in which a ball is placed in an unstable position on a saddle shape. The ball becomes stable when it is rotated above some threshold angular velocity. The demonstration is a mechanical analog of confining a particle in a "Paul Trap". (DDR)

  8. The Universal Trap.

    ERIC Educational Resources Information Center

    Goodman, Paul

    The compulsory system of education is criticized on the grounds that it has become a regimented "universal trap" antithetical to democracy. In contrast to the Jeffersonian concept of education in the service of citizen initiative for the preservation of freedom, current compulsory education is a tool of industrialism and of a rigidly stratified…

  9. WATER-TRAPPED WORLDS

    SciTech Connect

    Menou, Kristen

    2013-09-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO{sub 2} as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.

  10. Unitary Penning traps

    NASA Astrophysics Data System (ADS)

    Tan, Joseph; Brewer, Samuel; Guise, Nicholas

    2012-06-01

    We have constructed Penning traps in extremely compact forms, with unitary architectures that fully integrate NdFeB magnets (1.2 Tesla remnant magnetic field) within the electrode structure (occupying < 150 cm^3 assembled). A room-temperature apparatus has proven to be very useful in slowing and capturing ions extracted from an electron beam ion trap (EBIT).ootnotetextJ. N. Tan, S. M. Brewer, and N. D. Guise, to appear in Review of Scientific Instruments Here we present a two-magnet Penning trap designed to facilitate ion manipulation and optical experiments with stored ions. Some test results are presented. Experiments using this novel system are discussed in two presentations at this meeting.ootnotetextN.D. Guise, et al., ``Charge exchange and spectroscopy with isolated highly-charged ions,'' at this meeting.^,ootnotetextS. M. Brewer, et al., ``Observing forbidden radiative decay of highly-charged ions in a compact Penning trap,'' at this meeting. Unitary architecture can be particularly advantageous in small-instrument development (e.g., mass spectrometers) and in facilities or missions that have severe space constraints.

  11. Traps and trapping techniques for adult mosquito control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An overview is presented of the recent advancements in research activities conducted to evaluate mosquito traps, insecticide-impregnated targets baited with combinations of attractants, and strategies for using mass trapping techniques for adult mosquito population management. Technologies that use...

  12. Trapping cold molecular hydrogen.

    PubMed

    Seiler, Ch; Hogan, S D; Merkt, F

    2011-11-14

    Translationally cold H(2) molecules excited to non-penetrating |M(J)| = 3 Rydberg states of principal quantum number in the range 21-37 have been decelerated and trapped using time-dependent inhomogeneous electric fields. The |M(J)| = 3 Rydberg states were prepared from the X (1)Σ(+)(u)(v = 0, J = 0) ground state using a resonant three-photon excitation sequence via the B (1)Σ(+)(u)(v = 3, J = 1) and I (1)Π(g) (v = 0, J = 2) intermediate states and circularly polarized laser radiation. The circular polarization of the vacuum ultraviolet radiation used for the B ← X transition was generated by resonance-enhanced four-wave mixing in xenon and the degree of circular polarization was determined to be 96%. To analyse the deceleration and trapping experiments, the Stark effect in Rydberg states of molecular hydrogen was calculated using a matrix diagonalization procedure similar to that presented by Yamakita et al., J. Chem. Phys., 2004, 121, 1419. Particular attention was given to the prediction of zero-field positions of low-l states and of avoided crossings between Rydberg-Stark states with different values of |M(J)|. The calculated Stark maps and probabilities for diabatic traversal of the avoided crossings were used as input to Monte-Carlo particle-trajectory simulations. These simulations provide a quantitatively satisfactory description of the experimental data and demonstrate that particle loss caused by adiabatic traversals of avoided crossings between adjacent |M(J)| = 3 Stark states of H(2) is small at principal quantum numbers beyond n = 25. The main source of trap losses was found to be from collisional processes. Predissociation following the absorption of blackbody radiation is estimated to be the second most important trap-loss mechanism at room temperature, and trap loss by spontaneous emission is negligible under our experimental conditions. PMID:21818497

  13. Laser desorption in an ion trap mass spectrometer

    SciTech Connect

    Eiden, G.C.; Cisper, M.E.; Alexander, M.L.; Hemberger, P.H.; Nogar, N.S.

    1993-02-01

    Laser desorption in a ion-trap mass spectrometer shows significant promise for both qualitative and trace analysis. Several aspects of this methodology are discussed in this work. We previously demonstrated the generation of both negative and positive ions by laser desorption directly within a quadrupole ion trap. In the present work, we explore various combinations of d.c., r.f., and time-varying fields in order to optimize laser generated signals. In addition, we report on the application of this method to analyze samples containing compounds such as amines, metal complexes, carbon clusters, and polynuclear aromatic hydrocarbons. In some cases the ability to rapidly switch between positive and negative ion modes provides sufficient specificity to distinguish different compounds of a mixture with a single stage of mass spectrometry. In other experiments, we combined intensity variation studies with tandem mass spectrometry experiments and positive and negative ion detection to further enhance specificity.

  14. Towards optical optimization of planar monolithic perovskite/silicon-heterojunction tandem solar cells

    NASA Astrophysics Data System (ADS)

    Albrecht, Steve; Saliba, Michael; Correa-Baena, Juan-Pablo; Jäger, Klaus; Korte, Lars; Hagfeldt, Anders; Grätzel, Michael; Rech, Bernd

    2016-06-01

    Combining inorganic–organic perovskites and crystalline silicon into a monolithic tandem solar cell has recently attracted increased attention due to the high efficiency potential of this cell architecture. Promising results with published efficiencies above 21% have been reported so far. To further increase the device performance, optical optimizations enabling device related guidelines are highly necessary. Here we experimentally show the optical influence of the ITO thickness in the interconnecting layer and fabricate an efficient monolithic tandem cell with a reduced ITO layer thickness that shows slightly improved absorption within the silicon sub-cell and a stabilized power output of 17%. Furthermore we present detailed optical simulations on experimentally relevant planar tandem stacks to give practical guidelines to reach efficiencies above 25%. By optimizing the thickness of all functional and the perovskite absorber layers, together with the optimization of the perovskite band-gap, we present a tandem stack that can yield ca 17.5 mA cm‑ 2 current in both sub-cells at a perovskite band-gap of 1.73 eV including losses from reflection and parasitic absorption. Assuming that the higher band-gap of the perovskite absorber directly translates into a higher open circuit voltage, the perovskite sub-cell should be able to reach a value of 1.3 V. With that, realistic efficiencies above 28% are within reach for planar monolithic tandem cells in which the thickness of the perovskite top-cell and the perovskite band-gap are highly optimized. When applying light trapping schemes such as textured surfaces and by reducing the parasitic absorption of the functional layers, for example in spiro-OMeTAD, this monolithic tandem can overcome 30% power conversion efficiency.

  15. MODIFICATION OF CC WHITEFLY TRAPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modifications of CC whitefly traps are in progress to improve their potential for adult whitefly control in greenhouses. Adult catches in the modified CC traps have been increased by 50% by coating trap tops with Tanglefoot and removing the deflector plates. In laboratory studies, installation of ...

  16. Micromorph tandem solar cells: optimization of the microcrystalline silicon bottom cell in a single chamber system

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Dan; Zheng, Xin-Xia; Xu, Sheng-Zhi; Lin, Quan; Wei, Chang-Chun; Sun, Jian; Geng, Xin-Hua; Zhao, Ying

    2011-10-01

    We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.

  17. Radial cold trap

    DOEpatents

    Grundy, Brian R.

    1981-01-01

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

  18. Radial cold trap

    DOEpatents

    Grundy, B.R.

    1981-09-29

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

  19. Phosphorous trapped within buckminsterfullerene

    NASA Astrophysics Data System (ADS)

    Larsson, J. A.; Greer, J. C.; Harneit, W.; Weidinger, A.

    2002-05-01

    Under normal circumstances, when covalent molecules form, electrons are exchanged between atoms to form bonds. However, experiment and theoretical computations reveal exactly the opposite effect for the formation of group V elements nitrogen and phosphorous encapsulated within a buckminsterfullerene molecule. The C60 carbon cage remains intact upon encapsulation of the atom, whereas the electronic charge cloud of the N or P atom contracts. We have studied the chemical, spin, and thermodynamic properties of endohedral phosphorous (P@C60) and have compared our results with earlier findings for N@C60. From a combined experimental and theoretical vantage, we are able to elucidate a model for the interaction between the trapped group V atom and the fullerene cage. A picture emerges for the electronic structure of these complexes, whereby an atom is trapped within a fullerene, and interacts weakly with the molecular orbitals of the C60 cage.

  20. Filter vapor trap

    DOEpatents

    Guon, Jerold

    1976-04-13

    A sintered filter trap is adapted for insertion in a gas stream of sodium vapor to condense and deposit sodium thereon. The filter is heated and operated above the melting temperature of sodium, resulting in a more efficient means to remove sodium particulates from the effluent inert gas emanating from the surface of a liquid sodium pool. Preferably the filter leaves are precoated with a natrophobic coating such as tetracosane.

  1. Tandem Mirror Reactor Systems Code (Version I)

    SciTech Connect

    Reid, R.L.; Finn, P.A.; Gohar, M.Y.; Barrett, R.J.; Gorker, G.E.; Spampinaton, P.T.; Bulmer, R.H.; Dorn, D.W.; Perkins, L.J.; Ghose, S.

    1985-09-01

    A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost.

  2. Evaluation of ion trap mass spectrometry for the determination of ambient nicotine

    SciTech Connect

    Wise, M.B.; Higgins, C.E.; Ilgner, R.H.; Guerin, M.R.

    1989-01-01

    A thermal desorption unit has been interfaced directly with a Finnigan Ion Trap mass spectrometer (ITMS) for the identification and quantification of trace organics in air. No chromatographic separation of the desorbed constituents is performed prior to introduction into the mass spectrometer. Instead, positive identification of a compound is made based on its collision induced dissociation (CID) tandem (MS/MS) mass spectrum. Using this technique, as little as 50 pg of a constituent desorbed from resin trap can be characterized and quantified with a sample turnaround time of only 2--3 minutes. 3 refs.

  3. Magnetic trap for thulium atoms

    SciTech Connect

    Sukachev, D D; Sokolov, A V; Chebakov, K A; Akimov, A V; Kolachevskii, N N; Sorokin, Vadim N

    2011-08-31

    For the first time ultra-cold thulium atoms were trapped in a magnetic quadrupole trap with a small field gradient (20 Gs cm{sup -1}). The atoms were loaded from a cloud containing 4x10{sup 5} atoms that were preliminarily cooled in a magneto-optical trap to the sub-Doppler temperature of 80 {mu}K. As many as 4x10{sup 4} atoms were trapped in the magnetic trap at the temperature of 40 {mu}K. By the character of trap population decay the lifetime of atoms was determined (0.5 s) and an upper estimate was obtained for the rate constant of inelastic binary collisions for spin-polarised thulium atoms in the ground state (g{sub in} < 10{sup -11}cm{sup 3} s{sup -1}). (magnetic traps)

  4. The potential of combining ion trap/MS/MS and TOF/MS for identification of emerging contaminants

    USGS Publications Warehouse

    Ferrer, I.; Furlong, E.T.; Heine, C.E.; Thurman, E.M.

    2002-01-01

    The use of a method combining ion trap tandem mass spectrometry (MS/MS) and time of flight mass spectrometry (TOF/MS) for identification of emerging contaminates was discussed. The two tools together complemented each other in sensitivity, fragmentation and accurate mass determination. Liquid chromatography/electrospray ionization/ion-trap tandem mass spectrometry (LC/ESI/MS/MS), in positive ion mode of operation, was used to separate and identify specific compounds. Diagnostic fragment ions were obtained for a polyethyleneglycol(PEG) homolog by ion trap MS/MS, and fragments were measured by TOF/MS. It was observed that the combined method gave an exact mass measurement that differed from the calculated mass.

  5. Tandem balloon catheter for coronary angioplasty.

    PubMed

    Finci, L; Meier, B; Steffenino, G; Rutishauser, W

    1986-01-01

    The Tandem balloon catheter is a triple lumen steerable catheter for coronary angioplasty with two separately inflatable balloons of different diameters. Indications and results of 26 consecutive patients treated with a Tandem balloon catheter are reviewed. Adequate distal pressure measurements were obtained in 71% of the cases. In ten patients, the Tandem balloon catheter was selected for two stenoses in different segments of the same coronary artery. Angioplasty was successful for all lesions in five and for at least the strategic lesions in five patients (in one only after changing to a single-balloon catheter). In the seven patients with stenoses in two different coronary arteries of various calibers, angioplasty was successful for both vessels in three and for one vessel in four patients. In the six patients with a very tight stenosis, where the Tandem balloon catheter was selected to predilate with the small balloon, the procedure was technically successful in all, but there was a myocardial infarction in one patient. In the three patients with a chronic total occlusion, where the stiffness of the Tandem balloon was the reason for selection, one recanalization was successful. The Tandem balloon catheter provides a handy tool for complex coronary angioplasty. It offers comparable ease in manipulation and pressure transmission and may save time, money, and radiation exposure by avoiding catheter exchanges. PMID:2949848

  6. Neutrophil extracellular traps in sheep mastitis.

    PubMed

    Pisanu, Salvatore; Cubeddu, Tiziana; Pagnozzi, Daniela; Rocca, Stefano; Cacciotto, Carla; Alberti, Alberto; Marogna, Gavino; Uzzau, Sergio; Addis, Maria Filippa

    2015-01-01

    Neutrophil extracellular traps (NETs) are structures composed of DNA, histones, and antimicrobial proteins that are released extracellularly by neutrophils and other immune cells as a means for trapping and killing invading pathogens. Here, we describe NET formation in milk and in mammary alveoli of mastitic sheep, and provide a dataset of proteins found in association to these structures. Nucleic acid staining, immunomicroscopy and fluorescent in-situ hybridization of mastitic mammary tissue from sheep infected with Streptococcus uberis demonstrated the presence of extranuclear DNA colocalizing with antimicrobial proteins, histones, and bacteria. Then, proteomic analysis by LTQ-Orbitrap Velos mass spectrometry provided detailed information on protein abundance changes occurring in milk upon infection. As a result, 1095 unique proteins were identified, of which 287 being significantly more abundant in mastitic milk. Upon protein ontology classification, the most represented localization classes for upregulated proteins were the cytoplasmic granule, the nucleus, and the mitochondrion, while function classes were mostly related to immune defence and inflammation pathways. All known NET markers were massively increased, including histones, granule proteases, and antimicrobial proteins. Of note was the detection of protein arginine deiminases (PAD3 and PAD4). These enzymes are responsible for citrullination, the post-translational modification that is known to trigger NET formation by inducing chromatin decondensation and extracellular release of NETs. As a further observation, citrullinated residues were detected by tandem mass spectrometry in histones of samples from mastitic animals. In conclusion, this work provides novel microscopic and proteomic information on NETs formed in vivo in the mammary gland, and reports the most complete database of proteins increased in milk upon bacterial mastitis. PMID:26088507

  7. Diesel particulate trap mounting system

    SciTech Connect

    Miller, P.R.

    1992-01-21

    This patent describes a particulate trap assembly. It comprises an outer housing having a gas inlet and a gas outlet and a passageway interconnecting the gas inlet and the gas outlet; a particulate trapping means located within the passageway of the housing for trapping particles entrained in gas passing through the passageway, the passageway and the particulate trapping means having circumferential extents which fall within relatively large predetermined manufacturing tolerances respectively; tourniquet means surrounding the particulate trapping means for applying a predetermined radial pressure to the trapping means which is substantially independent of the circumferential extents of the passageway and the including an encircling element having a selectably adjustable circumferential extent for permitting the tourniquet means to conform to the circumferential extent of the particulate trapping means when mounted in compressive relationship about the particulate trapping means, and mounting means for retaining the particulate trapping means radially and axially within the passageway in a manner which imposes no further substantial radial compressive force to the particulate trapping means.

  8. Atom trap trace analysis

    SciTech Connect

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  9. Cryogenic resonator design for trapped ion experiments in Paul traps

    NASA Astrophysics Data System (ADS)

    Brandl, M. F.; Schindler, P.; Monz, T.; Blatt, R.

    2016-06-01

    Trapping ions in Paul traps require high radio frequency voltages, which are generated using resonators. When operating traps in a cryogenic environment, an in-vacuum resonator showing low loss is crucial to limit the thermal load to the cryostat. In this study, we present a guide for the design and production of compact, shielded cryogenic resonators. We produced and characterized three different types of resonators and furthermore demonstrate efficient impedance matching of these resonators at cryogenic temperatures.

  10. Ion microstability in tandem mirrors

    SciTech Connect

    Pearlstein, L.D.

    1983-08-29

    The formalism describing ion-cyclotron modes in mirror traps will be developed. Emphasis will be placed on the effects of finite axial boundaries on the normal modes of the system. Wave properties are a composite picture of: positive energy waves (plasma oscillation, shear Alfven and drift waves), negative energy waves (ion Bernstein waves in a loss-cone media), positive dissipation (electron Landau damping, outgoing waves), and negative dissipation (ion cyclotron damping in a loss-cone and anisotropic temperature medium). Stability boundaries in this bounded media is affected by scale lengths along the magnetic field; first, because they determine the widths of the resonances, and second, because they restrict the parallel structure of the modes.

  11. Systematic Comparison of a Two-dimensional Ion Trap and a Three-dimensional Ion Trap Mass Spectrometer in Proteomics*S

    PubMed Central

    Mayya, Viveka; Rezaul, Karim; Cong, Yu-Sheng; Han, David

    2006-01-01

    The utility and advantages of the recently introduced two-dimensional quadrupole ion trap mass spectrometer in proteomics over the traditional three-dimensional ion trap mass spectrometer have not been systematically characterized. Here we rigorously compared the performance of these two platforms by using over 100,000 tandem mass spectra acquired with identical complex peptide mixtures and acquisition parameters. Specifically we compared four factors that are critical for a successful proteomic study: 1) the number of proteins identified, 2) sequence coverage or the number of peptides identified for every protein, 3) the data base matching SEQUEST Xcorr and Sp score, and 4) the quality of the fragment ion series of peptides. We found a 4–6-fold increase in the number of peptides and proteins identified on the two-dimensional ion trap mass spectrometer as a direct result of improvement in all the other parameters examined. Interestingly more than 70% of the doubly and triply charged peptides, but not the singly charged peptides, showed better quality of fragmentation spectra on the two-dimensional ion trap. These results highlight specific advantages of the two-dimensional ion trap over the conventional three-dimensional ion traps for protein identification in proteomic experiments. PMID:15608339

  12. Characteristics of Ion Activation and Collision Induced Dissociation Using Digital Ion Trap Technology.

    PubMed

    Xu, Fuxing; Dang, Qiankun; Dai, Xinhua; Fang, Xiang; Wang, Yuanyuan; Ding, Li; Ding, Chuan-Fan

    2016-08-01

    Collision induced dissociation (CID) is one of the most established techniques for tandem mass spectrometry analysis. The CID of mass selected ion could be realized by ion resonance excitation with a digital rectangular waveform. The method is simple, and highly efficient CID result could be obtained by optimizing the experimental parameters, such as digital waveform voltage, frequency, and q value. In this work, the relationship between ion trapping waveform voltage and frequency at preselected q value, the relationship between waveform frequency and the q value at certain ion trapping voltage for optimum CID efficiency were investigated. Experiment results showed that the max CID efficiency of precursor reserpine ions can be obtained at different trapping waveform voltage and frequency when q and β are different. Based on systematic experimental analysis, the optimum experimental conditions for high CID efficiency can be calculated at any selected β or q. By using digital ion trap technology, the CID process and efficient fragmentation of parent ions can be realized by simply changing the trapping waveform amplitude, frequency, and the β values in the digital ion trap mass spectrometry. The technology and method are simple. It has potential use in ion trap mass spectrometry. Graphical Abstract ᅟ. PMID:27150507

  13. Characteristics of Ion Activation and Collision Induced Dissociation Using Digital Ion Trap Technology

    NASA Astrophysics Data System (ADS)

    Xu, Fuxing; Dang, Qiankun; Dai, Xinhua; Fang, Xiang; Wang, Yuanyuan; Ding, Li; Ding, Chuan-Fan

    2016-08-01

    Collision induced dissociation (CID) is one of the most established techniques for tandem mass spectrometry analysis. The CID of mass selected ion could be realized by ion resonance excitation with a digital rectangular waveform. The method is simple, and highly efficient CID result could be obtained by optimizing the experimental parameters, such as digital waveform voltage, frequency, and q value. In this work, the relationship between ion trapping waveform voltage and frequency at preselected q value, the relationship between waveform frequency and the q value at certain ion trapping voltage for optimum CID efficiency were investigated. Experiment results showed that the max CID efficiency of precursor reserpine ions can be obtained at different trapping waveform voltage and frequency when q and β are different. Based on systematic experimental analysis, the optimum experimental conditions for high CID efficiency can be calculated at any selected β or q. By using digital ion trap technology, the CID process and efficient fragmentation of parent ions can be realized by simply changing the trapping waveform amplitude, frequency, and the β values in the digital ion trap mass spectrometry. The technology and method are simple. It has potential use in ion trap mass spectrometry.

  14. Characteristics of Ion Activation and Collision Induced Dissociation Using Digital Ion Trap Technology

    NASA Astrophysics Data System (ADS)

    Xu, Fuxing; Dang, Qiankun; Dai, Xinhua; Fang, Xiang; Wang, Yuanyuan; Ding, Li; Ding, Chuan-Fan

    2016-05-01

    Collision induced dissociation (CID) is one of the most established techniques for tandem mass spectrometry analysis. The CID of mass selected ion could be realized by ion resonance excitation with a digital rectangular waveform. The method is simple, and highly efficient CID result could be obtained by optimizing the experimental parameters, such as digital waveform voltage, frequency, and q value. In this work, the relationship between ion trapping waveform voltage and frequency at preselected q value, the relationship between waveform frequency and the q value at certain ion trapping voltage for optimum CID efficiency were investigated. Experiment results showed that the max CID efficiency of precursor reserpine ions can be obtained at different trapping waveform voltage and frequency when q and β are different. Based on systematic experimental analysis, the optimum experimental conditions for high CID efficiency can be calculated at any selected β or q. By using digital ion trap technology, the CID process and efficient fragmentation of parent ions can be realized by simply changing the trapping waveform amplitude, frequency, and the β values in the digital ion trap mass spectrometry. The technology and method are simple. It has potential use in ion trap mass spectrometry.

  15. Laser-based studies with an ion-trap mass spectrometer: Ion tomography and analytical applications

    NASA Astrophysics Data System (ADS)

    Alexander, M. L.; Cisper, M. E.; Hemberger, P. H.; Nogar, N. S.; Williams, J. D.; Syka, J. E. P.

    The iron trap mass spectrometer (ITMS) is an ion storage device which consists of two hyperbolic endcaps and a hyperbolic ring electrode. This forms a trapping cavity having a volume of several cm(sup 3). An RF potential applied to the ring electrode produces a time-varying potential which can be used to trap and/or manipulate ions under controlled conditions. This device has been used in ion trapping studies for a number of years. More recently, a commercial version has been produced and sold which allows for mass-selective ejection of trapped ions, with subsequent detection by an electron multiplier. In this mode, it operates as a compact, high efficiency, high resolution mass spectrometer. The instrument has found applications in GC/MS, in tandem mass spectroscopy and in portable mass spectral analysis. In this manuscript, we present a survey of recent results incorporating laser desorption, ionization, or photodissociation with ITMS. In one instance, we describe the use of laser photodissociation to map the spatial distribution of trapped ions in the ITMS. In this tomographic study, we have parameterized the effects of trapping potential, buffer gas pressure, supplementary RF-potential, and laser intensity. In separate studies, laser desorption was used to generate gas phase ions in the ITMS from a solid probe, by irradiation of both neat and matrix-dissolved samples. The latter experiment produced both high molecular weight ions and significant numbers of negative ions.

  16. Gated charged-particle trap

    DOEpatents

    Benner, W. Henry

    1999-01-01

    The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector.

  17. Trapping of interstitials in metals

    SciTech Connect

    Wert, C.A.; Frank, R.C.

    1983-01-01

    The term trapping is used extensively to refer to the fact that interstitial atoms often find interstices associated with lattice imperfections to be energetically preferable to normal sites. This preference results in a delay of diffusion of interstitial atoms near these sites. As understanding of the details of lattice imperfections has improved, understanding of the effect of traps on the diffusion process has increased. Trapping is often illustrated by the use of a potential energy diagram. This simple model is characterized by a potential energy well deeper than those of surrounding interstitial sites. The energy required for the interstitial to jump into the trap is the same as that required for jumping into other adjacent interstitial sites, but that required for jumping out is greater. The additional energy required to leave the site is often designated as the trap binding energy, E/sub B/. Potential energy diagrams appropriate for most traps in metals are likely to be more complicated, but this simple model is a starting point for more sophisticated models of trapping. Imperfections may occasionally produce interstitial sites less favorable than normal sites and thus be less preferred. Little experimental exploration of this anti-trapping phenomenon has been carried out, however. Developments in understanding at various levels of trapping of interstitial impurities by lattice imperfections are examined.

  18. Halo ion trap mass spectrometer.

    PubMed

    Austin, Daniel E; Wang, Miao; Tolley, Samuel E; Maas, Jeffrey D; Hawkins, Aaron R; Rockwood, Alan L; Tolley, H Dennis; Lee, Edgar D; Lee, Milton L

    2007-04-01

    We describe a novel radio frequency ion trap mass analyzer based on toroidal trapping geometry and microfabrication technology. The device, called the halo ion trap, consists of two parallel ceramic plates, the facing surfaces of which are imprinted with sets of concentric ring electrodes. Radii of the imprinted rings range from 5 to 12 mm, and the spacing between the plates is 4 mm. Unlike conventional ion traps, in which hyperbolic metal electrodes establish equipotential boundary conditions, electric fields in the halo ion trap are established by applying different radio frequency potentials to each ring. The potential on each ring can be independently optimized to provide the best trapping field. The halo ion trap features an open structure, allowing easy access for in situ ionization. The toroidal geometry provides a large trapping and analyzing volume, increasing the number of ions that can be stored and reducing the effects of space-charge on mass analysis. Preliminary mass spectra show resolution (m/Deltam) of 60-75 when the trap is operated at 1.9 MHz and 500 Vp-p. PMID:17335180

  19. Trapped-electron runaway effect

    NASA Astrophysics Data System (ADS)

    Nilsson, E.; Decker, J.; Fisch, N. J.; Peysson, Y.

    2015-08-01

    In a tokamak, trapped electrons subject to a strong electric field cannot run away immediately, because their parallel velocity does not increase over a bounce period. However, they do pinch toward the tokamak center. As they pinch toward the center, the trapping cone becomes more narrow, so eventually they can be detrapped and run away. When they run away, trapped electrons will have a very different signature from circulating electrons subject to the Dreicer mechanism. The characteristics of what are called trapped-electron runaways are identified and quantified, including their distinguishable perpendicular velocity spectrum and radial extent.

  20. Optimizing a tandem disk model

    SciTech Connect

    Healey, J.V.

    1983-07-01

    A very simple physicomathematical model, in which thin straight blades with zero drag skim across a plane rectangular disk, shows that the maximum power coefficient attains the classical maximum of 0.593 over a range of T and a zero or small negative value of alpha/sub 0/. This maximum appears independent of sigma and there are values of T and alpha/sub 0/ for which the speed through the disk becomes complex and the model breaks down. Extending this model to a tandem disk system leads to a difficulty in defining the power coefficient. Attempts to optimize the system output based on reference areas A/sub 1/, A/sub 2/, and A/sub 4/ prove futile and the sum of the coefficients is chosen for this purpose. For thin blades and zero drag the analytic solution is available and it shows that the maximum value of 2 X 0.593 is attained over a narrow range of slightly negative alpha/sub 0/ (blade nose in) and medium values of T. The maximum is independent of sigma. As T is increased, the model breaks down either after C /SUB psum/ becomes large and negative or after backflow through the downwind disk occurs. There appears to be no requirement on load distribution between the disks. By comparison, modeling a machine with NACA 0012 blades at Re = 1.34 X 10/sup 6/ shows that the maximum value of C /SUB psum/ depends on the solidity. For example, at sigma = 0.4, the maximum value of C /SUB psum/ is 83% of 2 X 0.593. At such high values of sigma, however, the ranges of alpha/sub 0/ and T over which solutions are available become very limited.

  1. ICRF heating of passing ions in a thermal barrier tandem mirror

    SciTech Connect

    Molvik, A.W.; Dimonte, G.; Campbell, R.; Barter, J.; Cummins, W.F.; Falabella, S.; Poulsen, P.

    1985-05-01

    Ion heating is used in the central cells of tandem mirrors to reduce the collisional trapping of passing ions in the end cell thermal barriers. In this paper, we reevaluate ICRF heating of the TMX-U central cell in two limits. The first we term isotropic, because we impose the condition that ions heated in the perpendicular direction be confined for at least one 90/sup 0/ scattering time, thereby heating the passing ions. The second we call anisotropic heating. It uses higher ICRF power to mirror trap a majority of the ions near the midplane, thereby reducing the density and collisionality of passing ions. Anisotropic heating has the advantage of increasing with ICRF power, whereas isotropic heating is limited by ion collisionality. Both techniques require gas fueling near the central cell midplane, with an ion cyclotron resonance toward each end cell to heat the cold ions.

  2. Tandem mass spectrometric analysis of glyphosate, glufosinate, aminomethylphosphonic acid and methylphosphinicopropionic acid.

    PubMed

    Goodwin, Lee; Startin, James R; Goodall, David M; Keely, Brendan J

    2003-01-01

    A detailed MS(n) study of glyphosate, glufosinate and their main metabolites, aminomethylphosphonic acid and methylphosphinicopropionic acid, using an ion trap mass spectrometer, was performed. The analytes show good response in negative ion electrospray mass spectrometry (ES-MS) as [M-H](-) ions. Tandem-MS spectra reveal a wealth of structurally specific ions, allowing characterisation of the fragmentation pathways of the four analytes in their native form for the first time. The ions formed at each stage of fragmentation reveal ions common to each analyte, such as phosphinate, as well as analyte specific transitions. Simplex optimisation allows optimum trapping and fragmentation parameters to be determined leading to improved response for particular transitions and transition sequences, and revealing previously unseen ions. PMID:12717770

  3. Traps and seals II. Stratigraphic/capillary traps

    SciTech Connect

    Foster, N.H.; Beaumont, E.A.

    1988-01-01

    This text is a reprint belonging to a series of reprint volumes which in turn are part of the Treatise of Petroleum Geology. This volume contains papers that describe different stratigraphically controlled trap types, the preservation of porosity, and the importance of capillarity in trapping hydrocarbons.

  4. 50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Area 1 trap limits. The Area 1 trap limit is 800 traps. Federally permitted lobster fishing vessels shall not fish with, deploy in, possess in, or haul back...

  5. A single trapped ion in a finite range trap

    SciTech Connect

    Bagheri Harouni, M.; Davoudi Darareh, M.

    2011-04-15

    Research Highlights: > We present a method to describe dynamics of an ion confined in a finite size trap. > The trap is modeled with a potential in the context of an f-deformed oscillator. > The ion exhibits nonclassical properties such as squeezing and quantum interference. > . > Also this system can be used to generate highly excited motional Fock state. > The Hilbert space size effects and nano traps can be investigated by this model. - Abstract: This paper presents a method to describe dynamics of an ion confined in a realistic finite range trap. We model this realistic potential with a solvable one and we obtain dynamical variables (raising and lowering operators) of this potential. We consider coherent interaction of this confined ion in a finite range trap and we show that its center-of-mass motion steady state is a special kind of nonlinear coherent states. Physical properties of this state and their dependence on the finite range of potential are studied.

  6. Cryogenic ion trapping systems with surface-electrode traps

    NASA Astrophysics Data System (ADS)

    Antohi, P. B.; Schuster, D.; Akselrod, G. M.; Labaziewicz, J.; Ge, Y.; Lin, Z.; Bakr, W. S.; Chuang, I. L.

    2009-01-01

    We present two simple cryogenic rf ion trap systems in which cryogenic temperatures and ultra high vacuum pressures can be reached in as little as 12 h. The ion traps are operated either in a liquid helium bath cryostat or in a low vibration closed cycle cryostat. The fast turn around time and availability of buffer gas cooling made the systems ideal for testing surface-electrode ion traps. The vibration amplitude of the closed cycled cryostat was found to be below 106 nm. We evaluated the systems by loading surface-electrode ion traps with S88r+ ions using laser ablation, which is compatible with the cryogenic environment. Using Doppler cooling we observed small ion crystals in which optically resolved ions have a trapped lifetime over 2500 min.

  7. Segmented trapped vortex cavity

    NASA Technical Reports Server (NTRS)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  8. Optimal traps in graphene

    NASA Astrophysics Data System (ADS)

    Downing, C. A.; Pearce, A. R.; Churchill, R. J.; Portnoi, M. E.

    2015-10-01

    We transform the two-dimensional Dirac-Weyl equation, which governs the charge carriers in graphene, into a nonlinear first-order differential equation for scattering phase shift, using the so-called variable-phase method. This allows us to utilize the Levinson theorem, relating scattering phase shifts of a slow particle to its bound states, to find zero-energy bound states created electrostatically in realistic structures. These confined states are formed at critical potential strengths, which leads us to posit the use of "optimal traps" to combat the chiral tunneling found in graphene: this could be explored experimentally with an artificial network of point charges held above the graphene layer. We also discuss scattering on these states and find that the s states create a dominant peak in the scattering cross section as the energy tends towards the Dirac point energy, suggesting a dominant contribution to the resistivity.

  9. Equatorially trapped plasma populations

    NASA Technical Reports Server (NTRS)

    Olsen, R. C.

    1981-01-01

    The SCATHA observations of the equatorially trapped plasmas are presented in order to emphasize the importance of making measurements at the equator. The UCSD plasma detector and the GSFC electric field experiment are described, as are the pertinent characteristics of the magnetometer and mass spectrometers. The electron distribution reveals a width of 20 deg to 60 deg, narrowing with increasing energy. The 20- to 100-eV ion fluxes typically exhibit temperatures in the 20to 50-eV range and densities of 1-10 per cu cm. The electron population typically ranges from 50 to 500 eV, with temperatures of 100-200 eV and densities also in the 1-10 per cu cm range. Field-aligned populations of lower energy are occasionally found in both ions and electrons at the same location.

  10. Tandem Catalysis Utilizing Olefin Metathesis Reactions.

    PubMed

    Zieliński, Grzegorz K; Grela, Karol

    2016-07-01

    Since olefin metathesis transformation has become a favored synthetic tool in organic synthesis, more and more distinct non-metathetical reactions of alkylidene ruthenium complexes have been developed. Depending on the conditions applied, the same olefin metathesis catalysts can efficiently promote isomerization reactions, hydrogenation of C=C double bonds, oxidation reactions, and many others. Importantly, these transformations can be carried out in tandem with olefin metathesis reactions. Through addition of one portion of a catalyst, a tandem process provides structurally advanced products from relatively simple substrates without the need for isolation of the intermediates. These aspects not only make tandem catalysis very attractive from a practical point of view, but also open new avenues in (retro)synthetic planning. However, in the literature, the term "tandem process" is sometimes used improperly to describe other types of multi-reaction sequences. In this Concept, a number of examples of tandem catalysis involving olefin metathesis are discussed with an emphasis on their synthetic value. PMID:27203528

  11. Characteristics of a trapped-vortex (TV) combustor

    NASA Technical Reports Server (NTRS)

    Hsu, K.-Y.; Gross, L. P.; Trump, D. D.; Roquemore, W. M.

    1994-01-01

    The characteristics of a Trapped-Vortex (TV) combustor are presented. A vortex is trapped in the cavity established between two disks mounted in tandem. Fuel and air are injected directly into the cavity in such a way as to increase the vortex strength. Some air from the annular flow is also entrained into the recirculation zone of the vortex. Lean blow-out limits of the combustor are determined for a wide range of annular air flow rates. These data indicate that the lean blow-out limits are considerably lower for the TV combustor than for flames stabilized using swirl or bluff-bodies. The pressure loss through the annular duct is also low, being less than 2% for the flow conditions in this study. The instantaneous shape of the recirculation zone of the trapped vortex is measured using a two-color PIV technique. Temperature profiles obtained with CARS indicate a well mixed recirculation zone and demonstrate the impact of primary air injection on the local equivalence ratio.

  12. Nontoxic Antifreeze for Insect Traps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Propylene glycol in water is a safe and effective alternative to ethylene glycol as a capture liquid in insect traps (pitfalls, flight intercepts, pan traps). Propylene glycol formulations are readily available because it is the primary (95%) ingredient in certain automotive antifreeze formulations...

  13. Mass trapping for Anastrepha suspensa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mass trapping has been found to be highly effective for control of pest fruit flies when populations are low and a highly effective lure is available for the target species. Successful population control through mass trapping is an indicator that attract-and-kill bait stations may be equally succes...

  14. Quantum computing with trapped ions

    SciTech Connect

    Hughes, R.J.

    1998-01-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  15. [Trapping techniques for Solenopsis invicta].

    PubMed

    Liang, Xiao-song; Zhang, Qiang; Zhuang, Yiong-lin; Li, Gui-wen; Ji, Lin-peng; Wang, Jian-guo; Dai, Hua-guo

    2007-06-01

    A field study was made to investigate the trapping effects of different attractants, traps, and wind directions on Solenopsis invicta. The results showed that among the test attractants, TB1 (50 g fishmeal, 40 g peptone, 10 ml 10% sucrose water solution and 20 ml soybean oil) had the best effect, followed by TB2 (ham), TB6 (100 g cornmeal and 20 ml soybean oil) and TB4 (10 ml 10% sucrose water solution, 100 g sugarcane powder and 20 ml soybean oil), with a mean capture efficiency being 77.6, 58.7, 29 and 7.7 individuals per trap, respectively. No S. invicta was trapped with TB3 (10 ml 10% sucrose water solution, 100 g cornmeal and 20 ml soybean oil) and TB5 (honey). Tube trap was superior to dish trap, with a trapping efficiency of 75.2 and 35 individuals per trap, respectively. The attractants had better effects in leeward than in windward. PMID:17763750

  16. Magnetostatic traps for charged and neutral particles

    NASA Astrophysics Data System (ADS)

    Gomer, V.; Harms, O.; Haubrich, D.; Schadwinkel, H.; Strauch, F.; Ueberholz, B.; Aus der Wiesche, S.; Meschede, D.

    1997-08-01

    We have constructed magnetostatic traps from permanent magnets for trapping charged and neutral atoms. Two storage experiments are presented: a compact Penning trap for light ions and magnetic trapping of single neutral atoms. The dynamics of cold neutral atoms and their loss mechanisms in a quadrupole magnetostatic trap are discussed.

  17. Titan and Enceladus mission (TANDEM)

    NASA Astrophysics Data System (ADS)

    Coustenis, A.

    2007-08-01

    Our understanding of Titan's atmosphere and surface has recently been enhanced by the data returned by the Cassini-Huygens mission. The Cassini orbiter will continue to be operational for about 3 more years during its extended mission. After this mission, any unanswered questions will forever remain unknown, unless we go back with an optimized orbital tour and advanced instrumentation. Considering the complementary nature of the geological, chemical and evolutionary history of Titan and Enceladus, we propose to carry out studies for a mission to perform an in situ exploration of these two objects in tandem. In our proposal we determine key science measurements, the types of samples that would be needed and the instrument suites for achieving the science goals. In particular, we develop conceptual designs for delivering the science payload, including orbiters, aerial platforms and probes, and define a launch/delivery/communication management architecture. This mission will require new technologies and capabilities so that the science goals can be achieved within the cost cap and acceptable risks. International participation will play a key role in achieving all the science goals of this mission. We will build this mission concept around a central core of single orbiter, a single Titan aerial probe and a core group of category 1 instruments. Aerobraking with Titan's atmosphere will be given serious consideration to minimize resource requirements and risk. This approach will allow a single orbiter to be used for both Enceladus science and Titan science with final orbit around Titan and later release of aerial probe(s) into Titan's atmosphere. The Titan aerial probe may be a Montgolfière balloon concept that will use the waster heat ~ 1000 watts from a single RTG power system. There will be a release of penetrator(s) on Enceladus also. This proposal addresses directly several of the scientific questions highlighted in the ESA Cosmic Vision 2015-2025 call, particularly

  18. Nanocarpets for Trapping Microscopic Particles

    NASA Technical Reports Server (NTRS)

    Noca, Flavio; Chen, Fei; Hunt, Brian; Bronikowski, Michael; Hoenk, Michael; Kowalczyk, Robert; Choi, Daniel

    2004-01-01

    Nanocarpets that is, carpets of carbon nanotubes are undergoing development as means of trapping microscopic particles for scientific analysis. Examples of such particles include inorganic particles, pollen, bacteria, and spores. Nanocarpets can be characterized as scaled-down versions of ordinary macroscopic floor carpets, which trap dust and other particulate matter, albeit not purposefully. Nanocarpets can also be characterized as mimicking both the structure and the particle-trapping behavior of ciliated lung epithelia, the carbon nanotubes being analogous to cilia. Carbon nanotubes can easily be chemically functionalized for selective trapping of specific particles of interest. One could, alternatively, use such other three-dimensionally-structured materials as aerogels and activated carbon for the purposeful trapping of microscopic particles. However, nanocarpets offer important advantages over these alternative materials: (1) Nanocarpets are amenable to nonintrusive probing by optical means; and (2) Nanocarpets offer greater surface-to-volume ratios.

  19. Multiresidue determination of 11 new fungicides in grapes and wines by liquid-liquid extraction/clean-up and programmable temperature vaporization injection with analyte protectants/gas chromatography/ion trap mass spectrometry.

    PubMed

    González-Rodríguez, Rosa M; Cancho-Grande, Beatriz; Simal-Gándara, Jesús

    2009-08-01

    A gas chromatographic ion trap mass spectrometry (GC-ITMS) method was developed for the determination of 11 new generation fungicides (benalaxyl, benalaxyl-M, boscalid, cyazofamid, famoxadone, fenamidone, fluquinconazole, iprovalicarb, pyraclostrobin, trifloxystrobin and zoxamide) in grapes and wines. Samples were extracted with ethyl acetate:hexane (1:1, v/v) and cleaned-up with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartridges using acetonitrile:toluene (3:1, v/v) as eluent. The addition of analyte protectants (3-ethoxy-1,2-propanediol, d-sorbitol and l-gulonic acid gamma-lactone) in the final extracts allowed to avoid the matrix-induced response enhancement effect on quantitation process with absolute recoveries ca. 100%. Precision (expressed as relative standard deviation) was lower than 16% for all fungicides. Limits of detection and quantitation were lower than 0.01 mg/kg or mg/L, except for cyazofamid, much smaller in all cases than maximum residue levels (MRLs) established by European Union for grapes and by Switzerland and Italy for wines. The proposed method was applied to determine fungicide residues in three different white grapes for vinification produced in Ribeiro area in Galicia (NW Spain), as well as in their corresponding final wines. PMID:19576591

  20. High performance polymer tandem solar cell

    PubMed Central

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

    2015-01-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells. PMID:26669577

  1. Tandem transformation of glycerol to esters.

    PubMed

    Sotenko, Maria V; Rebroš, Martin; Sans, Victor S; Loponov, Konstantin N; Davidson, Matthew G; Stephens, Gill; Lapkin, Alexei A

    2012-12-31

    Tandem transformation of glycerol via microbial fermentation and enzymatic esterification is presented. The reaction can be performed with purified waste glycerol from biodiesel production in a continuous mode, combining continuous fermentation with membrane-supported enzymatic esterification. Continuous anaerobic fermentation was optimized resulting in the productivity of 2.4 g L⁻¹ h⁻¹ of 1,3-propanediol. Biphasic esterification of 1,3-propanediol was optimized to achieve ester yield of up to 75%. A hollow fibre membrane contactor with immobilized Rhizomucor miehei lipase was demonstrated for the continuous tandem fermentation-esterification process. PMID:22796408

  2. High performance polymer tandem solar cell

    NASA Astrophysics Data System (ADS)

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd. Rashid Bin; Jang, Jin

    2015-12-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells.

  3. Homicidal tandem bullet wound of the chest.

    PubMed

    Bentley, A J; Busuttil, A; Clifton, B; Sibbald, P

    1997-03-01

    An unusual case of a homicidal gunshot wound to the chest is reported in which two bullets were fired in unison as tandem bullets from a handgun. At autopsy, two intact bullets were retrieved from the body of the victim, yet there was only one entrance wound and a single bullet track across the chest wall and thoracic organs. An examination of the weapon and ammunition supported the likelihood of tandem bullets and suggested the probable mechanism for this event. Very few similar cases have been documented. PMID:9095302

  4. Alpha particle confinement in tandem mirrors

    SciTech Connect

    Devoto, R.S.; Ohnishi, M.; Kerns, J.; Woo, J.T.

    1980-10-10

    Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step.

  5. Advances in ion trap mass spectrometry: Photodissociation as a tool for structural elucidation

    SciTech Connect

    Stephenson, J.L. Jr.; Booth, M.M.; Eyler, J.R.; Yost, R.A.

    1995-12-01

    Photo-induced dissociation (PID) is the next most frequently used method (after collisional activation) for activation of Polyatomic ions in tandem mass spectrometry. The range of internal energies present after the photon absorption process are much narrower than those obtained with collisional energy transfer. Therefore, the usefulness of PID for the study of ion structures is greatly enhanced. The long storage times and instrumental configuration of the ion trap mass spectrometer are ideally suited for photodissociation experiments. This presentation will focus on both the fundamental and analytical applications of CO{sub 2} lasers in conjunction with ion trap mass spectrometry. The first portion of this talk will examine the fundamental issues of wavelength dependence, chemical kinetics, photoabsorption cross section, and collisional effects on photodissociation efficiency. The second half of this presentation will look at novel instrumentation for electrospray/ion trap mass spectrometry, with the concurrent development of photodissociation as a tool for structural elucidation of organic compounds and antibiotics.

  6. Improved Isobaric Tandem Mass Tag Quantification by Ion Mobility-Mass Spectrometry

    PubMed Central

    Li, Lingjun

    2014-01-01

    Isobaric tandem mass tags are an attractive alternative to mass difference tags and label free approaches for quantitative proteomics due to the high degree of multiplexing that can be performed with their implementation. A drawback of tandem mass tags are that the co-isolation and co-fragmentation of labeled peptide precursors can result in chimeric MS/MS spectra that can underestimate the fold-change expression of each peptide. Two methods (QuantMode and MS3) have addressed this concern for ion trap and orbitrap instruments, but there is still a need to solve this problem for quadrupole time-of-flight (Q-TOF) instruments. Ion mobility (IM) separations coupled to Q-TOF instruments have the potential to mitigate MS/MS spectra chimeracy since IM-MS has the ability to separate ions based on charge, m/z, and collision cross section (CCS). This work presents results that showcase the power of IM-MS to improve tandem mass tag peptide quantitation accuracy by resolving co-isolated differently charged and same charged peptides prior to MS/MS fragmentation. PMID:24677527

  7. The trapped human experiment.

    PubMed

    Huo, R; Agapiou, A; Bocos-Bintintan, V; Brown, L J; Burns, C; Creaser, C S; Devenport, N A; Gao-Lau, B; Guallar-Hoyas, C; Hildebrand, L; Malkar, A; Martin, H J; Moll, V H; Patel, P; Ratiu, A; Reynolds, J C; Sielemann, S; Slodzynski, R; Statheropoulos, M; Turner, M A; Vautz, W; Wright, V E; Thomas, C L P

    2011-12-01

    This experiment observed the evolution of metabolite plumes from a human trapped in a simulation of a collapsed building. Ten participants took it in turns over five days to lie in a simulation of a collapsed building and eight of them completed the 6 h protocol while their breath, sweat and skin metabolites were passed through a simulation of a collapsed glass-clad reinforced-concrete building. Safety, welfare and environmental parameters were monitored continuously, and active adsorbent sampling for thermal desorption GC-MS, on-line and embedded CO, CO(2) and O(2) monitoring, aspirating ion mobility spectrometry with integrated semiconductor gas sensors, direct injection GC-ion mobility spectrometry, active sampling thermal desorption GC-differential mobility spectrometry and a prototype remote early detection system for survivor location were used to monitor the evolution of the metabolite plumes that were generated. Oxygen levels within the void simulator were allowed to fall no lower than 19.1% (v). Concurrent levels of carbon dioxide built up to an average level of 1.6% (v) in the breathing zone of the participants. Temperature, humidity, carbon dioxide levels and the physiological measurements were consistent with a reproducible methodology that enabled the metabolite plumes to be sampled and characterized from the different parts of the experiment. Welfare and safety data were satisfactory with pulse rates, blood pressures and oxygenation, all within levels consistent with healthy adults. Up to 12 in-test welfare assessments per participant and a six-week follow-up Stanford Acute Stress Response Questionnaire indicated that the researchers and participants did not experience any adverse effects from their involvement in the study. Preliminary observations confirmed that CO(2), NH(3) and acetone were effective markers for trapped humans, although interactions with water absorbed in building debris needed further study. An unexpected observation from the NH(3

  8. [Microchip-based reversed-phase liquid chromatography-tandem mass spectrometry platform for protein analysis].

    PubMed

    Liang, Yu; Wu, Ci; Dai, Zhongpeng; Liang, Zuocheng; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2011-06-01

    Due to the high throughput and high sensitivity, the hyphenation of microchip-based high performance liquid chromatography with tandem mass spectrometry has been paid much attention. In our recent work, with poly (lauryl methacrylate-co-trimethylolpropane trimethacrylate) monolithic materials prepared in microchannels as trap and separation columns, conventional micro-liquid chromatography pumps and valves for fluidic control, and a small-bore open-tube capillary attached to the outlet channel as chip-mass spectrometer (MS) interface, the microchip-based reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) platform was established, and applied for the identification of proteins. By such platform, 100 ng digest of bovine serum albumin (BSA) was successfully analyzed with the sequence coverages as 39.37%, 37.89% and 34.10% (with the relative standard deviation (RSD) of 7.3%) in three runs, separately. To evaluate the chip-to-chip reproducibility, BSA was identified by such platform with the microchips from different batches containing trap column, separation column and chip-MS interface. The obtained sequence coverage and the number of peptides identified were comparable. All these results showed high sensitivity and good reproducibility of such platform, demonstrating the great potential for rapid protein analysis. PMID:22032155

  9. High voltage series connected tandem junction solar battery

    DOEpatents

    Hanak, Joseph J.

    1982-01-01

    A high voltage series connected tandem junction solar battery which comprises a plurality of strips of tandem junction solar cells of hydrogenated amorphous silicon having one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon, arranged in a tandem configuration, can have the same bandgap or differing bandgaps. The tandem junction strip solar cells are series connected to produce a solar battery of any desired voltage.

  10. Kinetically Stabilized Axisymmetric Tandem Mirrors: Summary of Studies

    SciTech Connect

    Post, R F

    2005-02-08

    The path to practical fusion power through plasma confinement in magnetic fields, if it is solely based on the present front-runner, the tokamak, is clearly long, expensive, and arduous. The root causes for this situation lie in the effects of endemic plasma turbulence and in the complexity the tokamak's ''closed'' field geometry. The studies carried out in the investigations described in the attached reports are aimed at finding an approach that does not suffer from these problems. This goal is to be achieved by employing an axisymmetric ''open'' magnetic field geometry, i.e. one generated by a linear array of circular magnet coils, and employing the magnetic mirror effect in accomplishing the plugging of end leakage. More specifically, the studies were aimed at utilizing the tandem-mirror concept in an axisymmetric configuration to achieve performance superior to the tokamak, and in a far simpler system, one for which the cost and development time could be much lower than that for the tokamak, as exemplified by ITER and its follow-ons. An important stimulus for investigating axisymmetric versions of the tandem mirror is the fact that, beginning from early days in fusion research there have been examples of axisymmetric mirror experiments where the plasma exhibited crossfield transport far below the turbulence-enhanced rates characteristic of tokamaks, in specific cases approaching the ''classical'' rate. From the standpoint of theory, axisymmetric mirror-based systems have special characteristics that help explain the low levels of turbulence that have been observed. Among these are the facts that there are no parallel currents in the equilibrium state, and that the drift surfaces of all of the trapped particles are closed surfaces, as shown early on by Teller and Northrop. In addition, in such systems it is possible to arrange that the radial boundary of the confined plasma terminates without contact with the chamber wall. This possibility reduces the

  11. Combined acoustic and optical trapping

    PubMed Central

    Thalhammer, G.; Steiger, R.; Meinschad, M.; Hill, M.; Bernet, S.; Ritsch-Marte, M.

    2011-01-01

    Combining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages of each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling of single particles. On the other hand, acoustic trapping with wavelengths of about 1 mm allows the simultaneous trapping of many, comparatively large particles. With conventional approaches it is difficult to fully employ the strengths of each method due to the different experimental requirements. Here we present the combined optical and acoustic trapping of motile micro-organisms in a microfluidic environment, utilizing optical macro-tweezers, which offer a large field of view and working distance of several millimeters and therefore match the typical range of acoustic trapping. We characterize the acoustic trapping forces with the help of optically trapped particles and present several applications of the combined optical and acoustic trapping, such as manipulation of large (75 μm) particles and active particle sorting. PMID:22025990

  12. Trap-mulching Argentine ants.

    PubMed

    Silverman, Jules; Sorenson, Clyde E; Waldvogel, Michael G

    2006-10-01

    Argentine ant, Linepithema humile (Mayr), management is constrained, in large part, by polydomy where nestmates are distributed extensively across urban landscapes, particularly within mulch. Management with trap-mulching is a novel approach derived from trap-cropping where ants are repelled from a broad domain of nest sites to smaller defined areas, which are subsequently treated with insecticide. This concept was field-tested with mulch surrounding ornamental trees replaced with a narrow band of pine (Pinus spp.) needle mulch (trap) within a much larger patch of repellent aromatic cedar (Juniperus spp.) mulch. After ants reestablished around the trees, the pine needle mulch band was treated with 0.06% fipronil (Termidor). Poor results were obtained when the trap extended from the tree trunk to the edge of the mulched area. When the trap was applied as a circular band around the tree trunk reductions in the number of foraging ants were recorded through 14 d compared with an untreated mulch control, but not for longer periods. Reductions in the number of ant nests within mulch were no different between the trap mulch and any of the other treatments. We conclude that trap-mulching offers limited benefits, and that successful management of Argentine ants will require implementation of complementary or perhaps alternative strategies. PMID:17066809

  13. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Canard or tandem wing configurations. 23.302 Section 23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  14. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Canard or tandem wing configurations. 23.302 Section 23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  15. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Canard or tandem wing configurations. 23.302 Section 23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  16. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Canard or tandem wing configurations. 23.302 Section 23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  17. 14 CFR 23.302 - Canard or tandem wing configurations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Canard or tandem wing configurations. 23.302 Section 23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... General § 23.302 Canard or tandem wing configurations. The forward structure of a canard or tandem...

  18. First Attempts at Antihydrogen Trapping in ALPHA

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A. J.; Jenkins, M. J.; Joergensen, L. V.; Madsen, N.; Werf, D. P. van der; Bray, C. C.; Chapman, S.; Fajans, J.; Povilus, A.; Wurtele, J. S.; Cesar, C. L.; Lambo, R.; Silveira, D. M.; Fujiwara, M. C.

    2008-08-08

    The ALPHA apparatus is designed to produce and trap antihydrogen atoms. The device comprises a multifunction Penning trap and a superconducting, neutral atom trap having a minimum-B configuration. The atom trap features an octupole magnet for transverse confinement and solenoidal mirror coils for longitudinal confinement. The magnetic trap employs a fast shutdown system to maximize the probability of detecting the annihilation of released antihydrogen. In this article we describe the first attempts to observe antihydrogen trapping.

  19. Characterizing single atom optical dipole traps

    NASA Astrophysics Data System (ADS)

    Shih, Chung-Yu; Gibbons, Michael; Chapman, Michael

    2012-06-01

    Trapping and manipulating individual neutral atoms in far off-resonant traps (FORTs) is a promising approach for quantum information processing. It is important to characterize the trapping environment of the atom and the atomic level shifts due to the trapping fields. Using non-destructive measurement techniques,ootnotetextM. J. Gibbons et al., Phys. Rev. Lett 106, 133002 (2011). we have measured the level dependent AC Stark shifts, trap frequencies, and temperature of single rubidium atoms confined in optical dipole trap.

  20. Assessing charge carrier trapping in silicon nanowires using picosecond conductivity measurements.

    PubMed

    Ulbricht, Ronald; Kurstjens, Rufi; Bonn, Mischa

    2012-07-11

    Free-standing semiconductor nanowires on bulk substrates are increasingly being explored as building blocks for novel optoelectronic devices such as tandem solar cells. Although carrier transport properties, such as mobility and trap densities, are essential for such applications, it has remained challenging to quantify these properties. Here, we report on a method that permits the direct, contact-free quantification of nanowire carrier diffusivity and trap densities in thin (∼25 nm wide) silicon nanowires-without any additional processing steps such as transfer of wires onto a substrate. The approach relies on the very different terahertz (THz) conductivity response of photoinjected carriers within the silicon nanowires from those in the silicon substrate. This allows quantifying both the picosecond dynamics and the efficiency of charge carrier transport from the silicon nanowires into the silicon substrate. Varying the excitation density allows for quantification of nanowire trap densities: for sufficiently low excitation fluences the diffusion process stalls because the majority of charge carriers become trapped at nanowire surface defects. Using a model that includes these effects, we determine both the diffusion constant and the nanowire trap density. The trap density is found to be orders of magnitude larger than the charge carrier density that would be generated by AM1.5 sunlight. PMID:22738182

  1. Tandem mirror fusion-fission hybrid studies

    NASA Astrophysics Data System (ADS)

    Lee, J. D.

    1980-04-01

    The concept of combining nuclear fusion and nuclear fission techniques is discussed. Initial tandem mirror hybrid studies predict the ability to produce large amounts of fissile fuel (2 to 7 tons U233 per year from a 4000 MW plant) at a cost that adds less than 25% to the cost of power from a light water reactor.

  2. Status of BINP proton tandem accelerator

    NASA Astrophysics Data System (ADS)

    Burdakov, A.; Davydenko, V.; Dolgushin, V.; Dranichnikov, A.; Ivanov, A.; Farrell, J. P.; Khilchenko, A.; Kobets, V.; Konstantinov, S.; Krivenko, A.; Kudryavtsev, A.; Tiunov, M.; Savkin, V.; Shirokov, V.; Sorokin, I.

    2007-08-01

    The status of a unique 2.0 MeV, 10 mA proton tandem accelerator with vacuum insulation is presented. The accelerator is intended to be used in facilities generating resonant gamma rays for explosives detection and epithermal neutrons for boron neutron-capture therapy of brain tumors. A magnetically coupled DC voltage multiplier derived from an industrial ELV-type electron accelerator is used as a high voltage source for the accelerator. A dc high current negative ion source has been developed for injection into the tandem. In the tandem accelerator there is set of nested potential electrodes with openings which form a channel for accelerating the negative hydrogen ion beam and subsequently accelerating the proton beam after stripping in the gas target. The electrodes are connected to a high voltage feedthrough insulator to which required potentials are applied from the high voltage power supply by means of a resistor voltage divider. In the paper the first experimental results obtained with the vacuum insulated tandem accelerator are also given.

  3. Tandem oligonucleotide synthesis using linker phosphoramidites

    PubMed Central

    Pon, Richard T.; Yu, Shuyuan

    2005-01-01

    Multiple oligonucleotides of the same or different sequence, linked end-to-end in tandem can be synthesized in a single automated synthesis. A linker phosphoramidite [R. T. Pon and S. Yu (2004) Nucleic Acids Res., 32, 623–631] is added to the 5′-terminal OH end of a support-bound oligonucleotide to introduce a cleavable linkage (succinic acid plus sulfonyldiethanol) and the 3′-terminal base of the new sequence. Conventional phosphoramidites are then used for the rest of the sequence. After synthesis, treatment with ammonium hydroxide releases the oligonucleotides from the support and cleaves the linkages between each sequence. Mixtures of one oligonucleotide with both 5′- and 3′-terminal OH ends and other oligonucleotides with 5′-phosphorylated and 3′-OH ends are produced, which are deprotected and worked up as a single product. Tandem synthesis can be used to make pairs of PCR primers, sets of cooperative oligonucleotides or multiple copies of the same sequence. When tandem synthesis is used to make two self-complementary sequences, double-stranded structures spontaneously form after deprotection. Tandem synthesis of oligonucleotide chains containing up to six consecutive 20mer (120 bases total), various trinucleotide codons and primer pairs for PCR, or self-complementary strands for in situ formation of double-stranded DNA fragments has been demonstrated. PMID:15814811

  4. 25 MV tandem accelerator at Oak Ridge

    SciTech Connect

    Jones, C.M.

    1980-01-01

    A new heavy-ion accelerator facility is under construction at the Oak Ridge National Laboratory. A brief description of the scope and status of this project is presented with emphasis on the first operational experience with the 25 MV tandem accelerator.

  5. Modelling of tandem cell temperature coefficients

    SciTech Connect

    Friedman, D.J.

    1996-05-01

    This paper discusses the temperature dependence of the basic solar-cell operating parameters for a GaInP/GaAs series-connected two-terminal tandem cell. The effects of series resistance and of different incident solar spectra are also discussed.

  6. Organic Tandem Solar Cells: Design and Formation

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chao

    In the past decade, research on organic solar cells has gone through an important development stage leading to major enhancements in power conversion efficiency, from 4% to 9% in single-junction devices. During this period, there are many novel processing techniques and device designs that have been proposed and adapted in organic solar-cell devices. One well-known device architecture that helps maximize the solar cell efficiency is the multi-junction tandem solar-cell design. Given this design, multiple photoactive absorbers as subcells are stacked in a monolithic fashion and assembled via series connection into one complete device, known as the tandem solar cell. Since multiple absorbers with different optical energy bandgaps are being applied in one tandem solar-cell device, the corresponding solar cell efficiency is maximized through expanded absorption spectrum and reduced carrier thermalization loss. In Chapter 3, the architecture of solution-processible, visibly transparent solar cells is introduced. Unlike conventional organic solar-cell devices with opaque electrodes (such as silver, aluminum, gold and etc.), the semi-transparent solar cells rely on highly transparent electrodes and visibly transparent photoactive absorbers. Given these two criteria, we first demonstrated the visibly transparent single-junction solar cells via the polymer absorber with near-infrared absorption and the top electrode based on solution-processible silver nanowire conductor. The highest visible transparency (400 ˜ 700 nm) of 65% was achieved for the complete device structure. More importantly, power conversion efficiency of 4% was also demonstrated. In Chapter 4, we stacked two semi-transparent photoactive absorbers in the tandem architecture in order to realize the semi-transparent tandem solar cells. A noticeable performance improvement from 4% to 7% was observed. More importantly, we modified the interconnecting layers with the incorporation of a thin conjugated

  7. Technology for large tandem mirror experiments

    SciTech Connect

    Thomassen, K.I.

    1980-09-04

    Construction of a large tandem mirror (MFTF-B) will soon begin at Lawrence Livermore National Laboratory (LLNL). Designed to reach break-even plasma conditions, the facility will significantly advance the physics and technology of magnetic-mirror-based fusion reactors. This paper describes the objectives and the design of the facility.

  8. Advances in Tandem Mirror fusion power reactors

    SciTech Connect

    Perkins, L.J.; Logan, B.G.

    1986-05-20

    The Tandem Mirror exhibits several distinctive features which make the reactor embodiment of the principle very attractive: Simple low-technology linear central cell; steady-state operation; high-..beta.. operation; no driven current or disruptions; divertorless operation; direction conversion of end-loss power; low-surface heat loads; and advanced fusion fuel capability. In this paper, we examine these features in connection with two tandem mirror reactor designs, MARS and MINIMARS, and several advanced reactor concepts including the wall-stabilized reactor and the field-reversed mirror. With a novel compact end plug scheme employing octopole stabilization, MINIMARS is expressly designed for short construction times, factory-built modules, and a small (600 MWe) but economic reactor size. We have also configured the design for low radioactive afterheat and inherent/passive safety under LOCA/LOFA conditions, thereby obviating the need for expensive engineered safety systems. In contrast to the complex and expensive double-quadrupole end-cell of the MARS reactor, the compact octopole end-cell of MINIMARS enables ignition to be achieved with much shorter central cell lengths and considerably improves the economy of scale for small (approx.250 to 600 MWe) tandem mirror reactors. Finally, we examine the prospects for realizing the ultimate potential of the tandem mirror with regard to both innovative configurations and novel neutron energy conversion schemes, and stress that advanced fuel applications could exploit its unique reactor features.

  9. Tandem mirror next step conceptual design

    SciTech Connect

    Doggett, J.N.; Damm, C.C.; Bulmer, R.H.

    1980-10-14

    A study was made to define the features of the experimental mirror fusion device - The Tandem Mirror Next Step, or TMNS - that will bridge the gap between present mirror confinement experiments and a power-producing reactor. We outline the project goals, describe some initial device parameters, and relate the technological requirements to ongoing development programs.

  10. Vortex interaction between two tandem flexible propulsors

    NASA Astrophysics Data System (ADS)

    Park, Sung Goon; Sung, Hyung Jin; Flow Control Laboratory Team

    2015-11-01

    Schooling behaviors of flying and swimming animals are widespread phenomena in nature. Inspired by schooling behaviors of swimming jellyfish, self-propelling flexible bodies with a paddling-based locomotion were modeled in a tandem configuration. The interactions between surrounding fluids and propulsors were considered by using the immersed boundary method. The hydrodynamic patterns generated by the interactions between tandem flexible propulsors were analyzed in the presen study. As a result of the flow-mediated interactions between them, stable configurations were formed spontaneously in which the gap distance between propulsors increased and decreased during the contraction and relaxation phases of the upstream propulsor. The stable configuration was not affected by the initial gap distance but influenced by the phase difference in the flapping frequency between them. Both tandem propulsors benefited from the tandem configuration in terms of the locomotion as compared with an isolated propulsor. This study was supported by the Creative Research Initiatives (No. 2015-001828) program of the National Research Foundation of Korea (MSIP).

  11. Inverted Three-Junction Tandem Thermophotovoltaic Modules

    NASA Technical Reports Server (NTRS)

    Wojtczuk, Steven

    2012-01-01

    An InGaAs-based three-junction (3J) tandem thermophotovoltaic (TPV) cell has been investigated to utilize more of the blackbody spectrum (from a 1,100 C general purpose heat source GPHS) efficiently. The tandem consists of three vertically stacked subcells, a 0.74-eV InGaAs cell, a 0.6- eV InGaAs cell, and a 0.55-eV InGaAs cell, as well as two interconnecting tunnel junctions. A greater than 20% TPV system efficiency was achieved by another group with a 1,040 C blackbody using a single-bandgap 0.6- eV InGaAs cell MIM (monolithic interconnected module) (30 lateral junctions) that delivered about 12 V/30 or 0.4 V/junction. It is expected that a three-bandgap tandem MIM will eventually have about 3 this voltage (1.15 V) and about half the current. A 4 A/cm2 would be generated by a single-bandgap 0.6-V InGaAs MIM, as opposed to the 2 A/cm2 available from the same spectrum when split among the three series-connected junctions in the tandem stack. This would then be about a 50% increase (3xVoc, 0.5xIsc) in output power if the proposed tandem replaced the single- bandgap MIM. The advantage of the innovation, if successful, would be a 50% increase in power conversion efficiency from radioisotope heat sources using existing thermophotovoltaics. Up to 50% more power would be generated for radioisotope GPHS deep space missions. This type of InGaAs multijunction stack could be used with terrestrial concentrator solar cells to increase efficiency from 41 to 45% or more.

  12. Vortex dynamics in anisotropic traps

    SciTech Connect

    McEndoo, S.; Busch, Th.

    2010-07-15

    We investigate the dynamics of linear vortex lattices in anisotropic traps in two dimensions and show that the interplay between the rotation and the anisotropy leads to a rich but highly regular dynamics.

  13. Trapping Protoplanets at the Snowlines.

    NASA Astrophysics Data System (ADS)

    Baillié, K.; Charnoz, S.; Pantin, E.

    2015-12-01

    We follow the viscous evolution of protoplanetary disks by modeling self-consistently their dynamics, thermodynamics, photosphere geometry and composition (Baillié & Charnoz., 2014, ApJ and Baillié et al., 2015, A&A). Our hydrodynamical numerical code allows us to estimate the local gradients in temperature and density that drive the type I migration of planetary embryos. In particular, we identify irregular structures in the disk: shadowed regions that are not directly irradiated by the star, temperature plateaux at the sublimation temperature of the main dust components of the disk. These icelines appear to be related with planetary traps. Though planetary embryos can be trapped temporarily in some early transient traps, the other traps (more permanent) will allow protoplanets to survive and favor their growth by collisions between embryos at some specific orbits.

  14. Mini ion trap mass spectrometer

    DOEpatents

    Dietrich, D.D.; Keville, R.F.

    1995-09-19

    An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

  15. Mini ion trap mass spectrometer

    DOEpatents

    Dietrich, Daniel D.; Keville, Robert F.

    1995-01-01

    An ion trap which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10.sup.9 and commercial mass spectrometers requiring 10.sup.4 ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products.

  16. The earth's trapped radiation belts

    NASA Technical Reports Server (NTRS)

    Noll, R. B.; Mcelroy, M. B.

    1975-01-01

    The near-earth charged particle environment is discussed in terms of spacecraft design criteria. Models are presented of the trapped radiation belts and based on in-situ data obtained from spacecraft.

  17. Acoustic trapping of active matter

    NASA Astrophysics Data System (ADS)

    Takatori, Sho C.; de Dier, Raf; Vermant, Jan; Brady, John F.

    2016-03-01

    Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine self-propelled particles in two dimensions over distances large compared with the swimmers' run length. We develop a near-harmonic trap to demonstrate the crossover from weak confinement, where the probability density is Boltzmann-like, to strong confinement, where the density is peaked along the perimeter. At high concentrations the swimmers crystallize into a close-packed structure, which subsequently `explodes' as a travelling wave when the tweezer is turned off. The swimmers' confined motion provides a measurement of the swim pressure, a unique mechanical pressure exerted by self-propelled bodies.

  18. Acoustic trapping of active matter.

    PubMed

    Takatori, Sho C; De Dier, Raf; Vermant, Jan; Brady, John F

    2016-01-01

    Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine self-propelled particles in two dimensions over distances large compared with the swimmers' run length. We develop a near-harmonic trap to demonstrate the crossover from weak confinement, where the probability density is Boltzmann-like, to strong confinement, where the density is peaked along the perimeter. At high concentrations the swimmers crystallize into a close-packed structure, which subsequently 'explodes' as a travelling wave when the tweezer is turned off. The swimmers' confined motion provides a measurement of the swim pressure, a unique mechanical pressure exerted by self-propelled bodies. PMID:26961816

  19. Hole-trapping in molecularly doped polymers

    NASA Astrophysics Data System (ADS)

    Borsenberger, Paul M.; Gruenbaum, William T.; Lin, Liang-Bih; Visser, Susan A.

    1998-04-01

    Hole mobilities have been measured in tri-p-tolylamine (TTA) doped poly(styrene) containing different concentrations of di- p-tolyl-p-anisylamine (DTA) or tri-p-anisylamine (TAA). DTA and TAA are traps with depths of 0.08 and 0.22 eV, respectively. For low concentrations of DTA or TAA, the transport processes are trap controlled and the mobilities decrease with increasing trap concentration. For high TAA concentrations, however, the transport processes are dominated by trap-to-trap hopping and the mobilities increase with increasing trap concentrations. The threshold concentration for the transition from trap controlled to trap-to-trap transport is approximately 10-1. A transition to trap- to-trap hopping is not observed for TTA containing DTA. The results are discussed within the framework of the Hoesterey- Letson formalism and the recent simulations of Wolf et al. and Borsenberger et al.

  20. Experimental investigation of planar ion traps

    SciTech Connect

    Pearson, C. E.; Leibrandt, D. R.; Bakr, W. S.; Mallard, W. J.; Brown, K. R.; Chuang, I. L.

    2006-03-15

    Chiaverini et al. [Quantum Inf. Comput. 5, 419 (2005)] recently suggested a linear Paul trap geometry for ion-trap quantum computation that places all of the electrodes in a plane. Such planar ion traps are compatible with modern semiconductor fabrication techniques and can be scaled to make compact, many-zone traps. In this paper we present an experimental realization of planar ion traps using electrodes on a printed circuit board to trap linear chains of tens of charged particles of 0.44 {mu}m diameter in a vacuum of 15 Pa (10{sup -1} torr). With these traps we address concerns about the low trap depth of planar ion traps and develop control electrode layouts for moving ions between trap zones without facing some of the technical difficulties involved in an atomic ion-trap experiment. Specifically, we use a trap with 36 zones (77 electrodes) arranged in a cross to demonstrate loading from a traditional four-rod linear Paul trap, linear ion movement, splitting and joining of ion chains, and movement of ions through intersections. We further propose an additional dc-biased electrode above the trap which increases the trap depth dramatically, and a planar ion-trap geometry that generates a two-dimensional lattice of point Paul traps.

  1. Progress at the Penning Trap Mass Spectrometer ``THe-Trap''

    NASA Astrophysics Data System (ADS)

    Hoecker, Martin; Eronen, Tommi; Ketter, Jochen; Streubel, Sebastian; Blaum, Klaus; van Dyck, Robert S.

    2012-03-01

    In 2008, the ``University of Washington Penning-Trap Mass Spectrometer'' (UW-PTMS), originally designed and built by the Van Dyck group, was moved to the Max-Planck-Insitute for Nuclear Physics in Heidelberg, Germany. It was set up in a dedicated laboratory that meets both the radiation-safety requirements, and the environment-stabilization demands for a high-precision measurement of the tritium/helium-3 mass ratio. Our goal is to measure this mass ratio with a relative uncertainty of 10-11, which would be more than an order of magnitude better than the previous best measurement. It would decrease the uncertainty in the tritium beta decay Q-value (an important parameter in the ongoing search for the neutrino mass by experiments such as KATRIN) by the same factor. In order to emphasize the specialization of our experiment with regard to Tritium and ^3Helium, it was renamed to ``THe-Trap''. THe-Trap features a double Penning-trap for rapid ion exchange, an external ion source to minimize trap contamination, a novel Zener-based voltage source, and active as well as passive stabilization of temperature, pressure and the magnetic field of the superconducting magnet. An overview of the project and a report on the recent progress will be given.

  2. Microfabricated ion trap mass spectrometry for characterization of organics and potential biomarkers

    NASA Astrophysics Data System (ADS)

    Austin, Daniel

    Mass spectrometry is a powerful analytical technique with a strong history in planetary exploration, and is the method of choice for detection and identification of organic and biological molecules. MS instrumentation can also be combined with techniques such as gas chromatography, liquid chromatography, or chiral separation, which are particularly important for analysis of complex mixtures or possible homochirality. Ion traps have several inherent advantages, including speed of analysis (important for GC-MS), MS/MS capabilities (important to identification of unknown compounds), excellent sensitivity, and ease of coupling with ambient ionization techniques that are under development for biomolecule detection. We report on progress in using microfabrication techniques to produce radiofrequency quadrupole ion traps that are much smaller, lighter, and lower power than existing instruments. We produce ion traps using an assembly of two ceramic plates, the facing surfaces of which are lithographically patterned with electrodes. This approach allows great flexibility in the trap geometry, and we have demonstrated working mass spectrometers with quadrupole, linear, and toroidal trapping fields. The approach also allows correction of higher-order terms in the electric field. With this system, mass resolution of up to 1300 has been demonstrated, which is adequate for identification of a wide range of potential biomarkers. Capabilities such as tandem analysis have also been demonstrated. Of particular interest is an ion trap that contains both quadrupole and toroidal trapping regions simultaneously and coaxially. Ions can be trapped as a large reservoir in the toroidal region and introduced in small batches to the quadrupole region for mass analysis. This capability is particularly valuable where the sample of interest is very small, such as microfossil with trace organics, and where the organic inventory is both complex and unknown. Development and results of this device

  3. Universal collisional activation ion trap mass spectrometry

    DOEpatents

    McLuckey, S.A.; Goeringer, D.E.; Glish, G.L.

    1993-04-27

    A universal collisional activation ion trap comprises an ion trapping means containing a bath gas and having connected thereto a noise signal generator. A method of operating a universal collisional activation ion trap comprises the steps of: providing an ion trapping means; introducing into the ion trapping means a bath gas; and, generating a noise signal within the ion trapping means; introducing into the ion trapping means a substance that, when acted upon by the noise signal, undergoes collisional activation to form product ions.

  4. Universal collisional activation ion trap mass spectrometry

    DOEpatents

    McLuckey, Scott A.; Goeringer, Douglas E.; Glish, Gary L.

    1993-01-01

    A universal collisional activation ion trap comprises an ion trapping means containing a bath gas and having connected thereto a noise signal generator. A method of operating a universal collisional activation ion trap comprises the steps of: providing an ion trapping means; introducing into the ion trapping means a bath gas; and, generating a noise signal within the ion trapping means; introducing into the ion trapping means a substance that, when acted upon by the noise signal, undergoes collisional activation to form product ions.

  5. Effect of bait in live trapping Peromyscus

    USGS Publications Warehouse

    Stickel, L.F.

    1948-01-01

    SUMMARY: Evidence from live trapping tests indicated that Peromyscus leucopus did not leave their home ranges because of the attraction of trap bait in nearby areas. A trap line down the center of a heavily live-trapped area caught as many mice before the area trapping as afterward. Thus, there was reason to believe that the area trapping did not serve to pre-bait the mice. Two unbaited lines of live traps caught an equal number of Peromyscus. When one line was baited with rolled oats and peanut butter the efficiency of the traps was improved to the extent that the baited line captured more than twice as many mice as the unbaited line. It is concluded that for the species and habitat tested it is safe to make population calculations based on the assumption that the animals remain within their home ranges and do not tend to move into the trapped area because of the attraction of the trap bait.

  6. Live trapping of hawks and owls

    USGS Publications Warehouse

    Stewart, R.E.; Cope, J.B.; Robbins, C.S.

    1945-01-01

    1. Hawks of six species (80 individuals) and owls of five species (37 individuals) were trapped for banding from November 1, 1943, to. May 26,1944. 2. In general, pole traps proved better than hand-operated traps or automatic traps using live bait. 3. Verbail pole traps proved very efficient, and were much more humane than padded steel traps because they rarely injured a captured bird. 4: Unbaited Verbail traps took a variety of raptors, in rough proportion to their local abundance, although slightly more of beneficial species were caught than of harmful types. 5. Hawks and owls were retrapped more readily in Verbail traps than in other types tried. 6. The number of song birds caught in Verbail traps was negligible. 7. Crows and vultures were not taken in Verbail traps, but possibly could be caught with bait.

  7. Comparison of emergence traps of different shape and translucency in the trapping of Culicoides (Diptera: Ceratopogonidae).

    PubMed

    Steinke, S; Lühken, R; Kroischke, F; Timmermann, E; Kiel, E

    2016-06-15

    Various types of emergence traps are available for investigations of the breeding habitats of Culicoides (Diptera: Ceratopogonidae). In order to assess the potential impact of the trap design on the trapping success, we compared the efficiency of opaque and white (more translucent) emergence traps and two trap shapes (cone-shaped and quadratic), to sample Culicoides emerging from cowpats. Significantly higher numbers of Culicoides chiopterus and Culicoides dewulfi were trapped with opaque traps, while there was no obvious effect of the trap shape. There were no distinct differences in the microclimate among different trap types. PMID:27198792

  8. Tandem microwave waste remediation and decontamination system

    DOEpatents

    Wicks, George G.; Clark, David E.; Schulz, Rebecca L.

    1999-01-01

    The invention discloses a tandem microwave system consisting of a primary chamber in which microwave energy is used for the controlled combustion of materials. A second chamber is used to further treat the off-gases from the primary chamber by passage through a susceptor matrix subjected to additional microwave energy. The direct microwave radiation and elevated temperatures provide for significant reductions in the qualitative and quantitative emissions of the treated off gases. The tandem microwave system can be utilized for disinfecting wastes, sterilizing materials, and/or modifying the form of wastes to solidify organic or inorganic materials. The simple design allows on-site treatment of waste by small volume waste generators.

  9. Locomotion by Tandem and Parallel Wings

    NASA Astrophysics Data System (ADS)

    Tanida, Yoshimichi

    A two-dimensional analysis was carried out on the locomotion by tandem and parallel wings in relation to the free flight of dragonflies and beetles, remarking the mutual interference between fore and hind wings. The results obtained are summarized as follows: In the case of tandem wings, (1)High thrust and propulsive efficiency can be achieved when the forewing oscillates with a definite phase lag behind the hindwing, as in the case of real dragonflies, (2)Somewhat smaller amplitude of hindwing leads to optimum condition for work sharing of two wings, (3)The hard forewing does not serve for the thrust and propulsive efficiency, whereas the hard hindwing does for the augmentation of them; In the case of parallel wings, (4)The hard wing placed near the soft wing acts nearly as an infinite plate, as for the ground effect, increasing both thrust and propulsive efficiency.

  10. Nucleic acid recognition by tandem helical repeats.

    PubMed

    Rubinson, Emily H; Eichman, Brandt F

    2012-02-01

    Protein domains constructed from tandem α-helical repeats have until recently been primarily associated with protein scaffolds or RNA recognition. Recent crystal structures of human mitochondrial termination factor MTERF1 and Bacillus cereus alkylpurine DNA glycosylase AlkD bound to DNA revealed two new superhelical tandem repeat architectures capable of wrapping around the double helix in unique ways. Unlike DNA sequence recognition motifs that rely mainly on major groove read-out, MTERF and ALK motifs locate target sequences and aberrant nucleotides within DNA by resculpting the double-helix through extensive backbone contacts. Comparisons between MTERF and ALK repeats, together with recent advances in ssRNA recognition by Pumilio/FBF (PUF) domains, provide new insights into the fundamental principles of protein-nucleic acid recognition. PMID:22154606

  11. Tritium measurements with a tandem accelerator

    NASA Astrophysics Data System (ADS)

    Middleton, R.; Klein, J.; Fink, D.

    1990-06-01

    Tritium concentrations ( 3H: 2H) of less than 10 -15 are readily measurable with almost any tandem accelerator and with an overall detection efficiency as high as 4.5%. The isobar, 3He, and other potential sources of interference (mainly 6Li, 2H and 1H) can all be removed by an absorber in front of the triton detector, so there is little need for analyzing elements other than the negative-and positive-ion magnets found on most tandems. The technique is particularly well suited for detecting tritium in deuterium absorbed in a metal and testing for cold fusion. We caution that tritium can occur in commercial deuterium and heavy water from sources other than cold fusion; one sample was observed to have a tritium-to-deuterium ratio of 10 -10.

  12. A comparison of pitfall traps with bait traps for studying leaf litter ant communities.

    PubMed

    Wang, C; Strazanac, J; Butler, L

    2001-06-01

    A comparison of pitfall traps with bait traps for sampling leaf litter ants was studied in oak-dominated mixed forests during 1995-1997. A total of 31,732 ants were collected from pitfall traps and 54,694 ants were collected from bait traps. They belonged to four subfamilies, 17 genera, and 32 species. Bait traps caught 29 species, whereas pitfall traps caught 31 species. Bait traps attracted one species not found in pitfall traps, but missed three of the species collected with pitfall traps. Collections from the two sampling methods showed differences in species richness, relative abundance, diversity, and species accumulation curves. Pitfall traps caught significantly more ant species per plot than did bait traps. The ant species diversity obtained from pitfall traps was higher than that from bait traps. Bait traps took a much longer time to complete an estimate of species richness than did pitfall traps. Little information was added to pitfall trapping results by the bait trapping method. The results suggested that the pitfall trapping method is superior to the bait trapping method for leaf litter ant studies. Species accumulation curves showed that sampling of 2,192+/-532 ants from six plots by pitfall traps provided a good estimation of ant species richness under the conditions of this study. PMID:11425034

  13. Cold Climate Heat Pumps Using Tandem Compressors

    SciTech Connect

    Shen, Bo; Abdelaziz, Omar; Rice, C Keith; Baxter, Van D

    2016-01-01

    In cold climate zones, e.g. ASHRAE climate regions IV and V, conventional electric air-source heat pumps (ASHP) do not work well, due to high compressor discharge temperatures, large pressure ratios and inadequate heating capacities at low ambient temperatures. Consequently, significant use of auxiliary strip heating is required to meet the building heating load. We introduce innovative ASHP technologies as part of continuing efforts to eliminate auxiliary strip heat use and maximize heating COP with acceptable cost-effectiveness and reliability. These innovative ASHP were developed using tandem compressors, which are capable of augmenting heating capacity at low temperatures and maintain superior part-load operation efficiency at moderate temperatures. Two options of tandem compressors were studied; the first employs two identical, single-speed compressors, and the second employs two identical, vapor-injection compressors. The investigations were based on system modeling and laboratory evaluation. Both designs have successfully met the performance criteria. Laboratory evaluation showed that the tandem, single-speed compressor ASHP system is able to achieve heating COP = 4.2 at 47 F (8.3 C), COP = 2.9 at 17 F (-8.3 C), and 76% rated capacity and COP = 1.9 at -13 F (-25 C). This yields a HSPF = 11.0 (per AHRI 210/240). The tandem, vapor-injection ASHP is able to reach heating COP = 4.4 at 47 F, COP = 3.1 at 17 F, and 88% rated capacity and COP = 2.0 at -13 F. This yields a HSPF = 12.0. The system modeling and further laboratory evaluation are presented in the paper.

  14. Electron irradiation of tandem junction solar cells

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.; Miyahira, T. F.; Scott-Monck, J. A.

    1979-01-01

    The electrical behavior of 100 micron thick tandem junction solar cells manufactured by Texas Instruments was studied as a function of 1 MeV electron fluence, photon irradiation, and 60 C annealing. These cells are found to degrade rapidly with radiation, the most serious loss occurring in the blue end of the cell's spectral response. No photon degradation was found to occur, but the cells did anneal a small amount at 60 C.

  15. Current and lattice matched tandem solar cell

    DOEpatents

    Olson, Jerry M.

    1987-01-01

    A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga.sub.x In.sub.1-x P (0.505.ltoreq.X.ltoreq.0.515) top cell semiconductor lattice matched to a GaAs bottom cell semiconductor at a low-resistance heterojunction, preferably a p+/n+ heterojunction between the cells. The top and bottom cells are both lattice matched and current matched for high efficiency solar radiation conversion to electrical energy.

  16. DDES and IDDES of tandem cylinders.

    SciTech Connect

    Balakrishnan, R.; Garbaruk, A.; Shur, M.; Strelets, M.; Spalart, P.; New Technologies and Services - Russia; St.-Peterburg State Polytechnic Univ.; Boeing Commercial Airplanes

    2010-09-09

    The paper presents an overview of the authors contribution to the BANC-I Workshop on the flow past tandem cylinders (Category 2). It includes an outline of the simulation approaches, numerics, and grid used, the major results of the simulations, their comparison with available experimental data, and some preliminary conclusions. The effect of varying the spanwise period in the simulations is strong for some quantities, and not others.

  17. Expression of tandem gene duplicates is often greater than twofold

    PubMed Central

    Loehlin, David W.; Carroll, Sean B.

    2016-01-01

    Tandem gene duplication is an important mutational process in evolutionary adaptation and human disease. Hypothetically, two tandem gene copies should produce twice the output of a single gene, but this expectation has not been rigorously investigated. Here, we show that tandem duplication often results in more than double the gene activity. A naturally occurring tandem duplication of the Alcohol dehydrogenase (Adh) gene exhibits 2.6-fold greater expression than the single-copy gene in transgenic Drosophila. This tandem duplication also exhibits greater activity than two copies of the gene in trans, demonstrating that it is the tandem arrangement and not copy number that is the cause of overactivity. We also show that tandem duplication of an unrelated synthetic reporter gene is overactive (2.3- to 5.1-fold) at all sites in the genome that we tested, suggesting that overactivity could be a general property of tandem gene duplicates. Overactivity occurs at the level of RNA transcription, and therefore tandem duplicate overactivity appears to be a previously unidentified form of position effect. The increment of surplus gene expression observed is comparable to many regulatory mutations fixed in nature and, if typical of other genomes, would shape the fate of tandem duplicates in evolution. PMID:27162370

  18. Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

    1995-01-01

    Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

  19. Numerical simulation and light trapping in perovskite solar cell

    NASA Astrophysics Data System (ADS)

    Iftiquar, Sk M.; Yi, Junsin

    2016-04-01

    A methyl ammonium lead iodide (H3NH3PbI3)-based solar cell can have photovoltaic conversion efficiency of more than 20%, primarily because the material shows lower defect density, high carrier mobility-lifetime, and broader absorption spectra. A further improvement in device efficiency can be obtained using light capture and trapping schemes, with textured front surface and back reflector. In order to understand characteristic performance of the device, we used numerical simulation and observed that more than 20% device efficiency can be obtained if defect density of the photosensitive material remains lower than 4×1014 cm-3 and thickness 400 nm or more. Investigation of light trapping scheme shows that the current density (J) can be raised with this scheme, but the most effective increase in the J can be observed for 97-nm thick active layers. Reverse saturation current density of these cells that may be directly related to recombination loss of photogenerated carriers, remains low, but increases linearly with the defect density. A tandem cell with pyramidally textured front surface was investigated with such a perovskite-based top cell and Si heterojunction bottom cell; it shows an efficiency of as high as 29.5%.

  20. TandEM: Titan and Enceladus mission

    USGS Publications Warehouse

    Coustenis, A.; Atreya, S.K.; Balint, T.; Brown, R.H.; Dougherty, M.K.; Ferri, F.; Fulchignoni, M.; Gautier, D.; Gowen, R.A.; Griffith, C.A.; Gurvits, L.I.; Jaumann, R.; Langevin, Y.; Leese, M.R.; Lunine, J.I.; McKay, C.P.; Moussas, X.; Muller-Wodarg, I.; Neubauer, F.; Owen, T.C.; Raulin, F.; Sittler, E.C.; Sohl, F.; Sotin, C.; Tobie, G.; Tokano, T.; Turtle, E.P.; Wahlund, J.-E.; Waite, J.H.; Baines, K.H.; Blamont, J.; Coates, A.J.; Dandouras, I.; Krimigis, T.; Lellouch, E.; Lorenz, R.D.; Morse, A.; Porco, C.C.; Hirtzig, M.; Saur, J.; Spilker, T.; Zarnecki, J.C.; Choi, E.; Achilleos, N.; Amils, R.; Annan, P.; Atkinson, D.H.; Benilan, Y.; Bertucci, C.; Bezard, B.; Bjoraker, G.L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M.T.; Chassefiere, E.; Coll, P.; Combes, M.; Cooper, J.F.; Coradini, A.; Crary, F.; Cravens, T.; Daglis, I.A.; de Angelis, E.; De Bergh, C.; de Pater, I.; Dunford, C.; Durry, G.; Dutuit, O.; Fairbrother, D.; Flasar, F.M.; Fortes, A.D.; Frampton, R.; Fujimoto, M.; Galand, M.; Grasset, O.; Grott, M.; Haltigin, T.; Herique, A.; Hersant, F.; Hussmann, H.; Ip, W.; Johnson, R.; Kallio, E.; Kempf, S.; Knapmeyer, M.; Kofman, W.; Koop, R.; Kostiuk, T.; Krupp, N.; Kuppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le, Mouelic S.; Lebonnois, S.; Ledvina, S.; Li, J.; Livengood, T.A.; Lopes, R.M.; Lopez-Moreno, J. -J.; Luz, D.; Mahaffy, P.R.; Mall, U.; Martinez-Frias, J.; Marty, B.; McCord, T.; Salvan, C.M.; Milillo, A.; Mitchell, D.G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, C.D.; Nixon, C.A.; Mvondo, D.N.; Orton, G.; Paetzold, M.; Pitman, J.; Pogrebenko, S.; Pollard, W.; Prieto-Ballesteros, O.; Rannou, P.; Reh, K.; Richter, L.; Robb, F.T.; Rodrigo, R.; Rodriguez, S.; Romani, P.; Bermejo, M.R.; Sarris, E.T.; Schenk, P.; Schmitt, B.; Schmitz, N.; Schulze-Makuch, D.; Schwingenschuh, K.; Selig, A.; Sicardy, B.; Soderblom, L.; Spilker, L.J.; Stam, D.; Steele, A.; Stephan, K.; Strobel, D.F.; Szego, K.; Szopa

    2009-01-01

    TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (Montgolfi??re) and possibly several landing probes to be delivered through the atmosphere. ?? Springer Science + Business Media B.V. 2008.

  1. Trapping biases of Culex torrentium and Culex pipiens revealed by comparison of captures in CDC traps, ovitraps, and gravid traps.

    PubMed

    Hesson, Jenny C; Ignell, Rickard; Hill, Sharon R; Östman, Örjan; Lundström, Jan O

    2015-06-01

    We evaluate three trapping methods for their effectiveness at capturing Culex pipiens and Culex torrentium, both enzootic vectors of bird-associated viruses in Europe. The comparisons, performed in two regions in Sweden, were among CDC traps baited with carbon dioxide, gravid traps, and ovitraps baited with hay infusion. The proportions of the two Culex species in a catch differed between trap types, with CDC traps catching a lower proportion of Cx. torrentium than both gravid traps and ovitraps. Between gravid traps and ovitraps, there was no difference in the proportions of the two species. The results indicate that Cx. torrentium may go undetected or underestimated compared to Cx. pipiens when using carbon dioxide baited CDC traps. The new insight of trap bias presented here adds an important dimension to consider when investigating these vectors of bird-associated viruses in the field. PMID:26047196

  2. Telomerase repeat amplification protocol (TRAP) activity upon recombinant expression and purification of human telomerase in a bacterial system.

    PubMed

    Hansen, Debra T; Thiyagarajan, Thirumagal; Larson, Amy C; Hansen, Jeffrey L

    2016-07-01

    Telomerase biogenesis is a highly regulated process that solves the DNA end-replication problem. Recombinant expression has so far been accomplished only within a eukaryotic background. Towards structural and functional analyses, we developed bacterial expression of human telomerase. Positive activity by the telomerase repeat amplification protocol (TRAP) was identified in cell extracts of Escherichia coli expressing a sequence-optimized hTERT gene, the full-length hTR RNA with a self-splicing hepatitis delta virus ribozyme, and the human heat shock complex of Hsp90, Hsp70, p60/Hop, Hsp40, and p23. The Hsp90 inhibitor geldanamycin did not affect post-assembly TRAP activity. By various purification methods, TRAP activity was also obtained upon expression of only hTERT and hTR. hTERT was confirmed by tandem mass spectrometry in a ∼120 kDa SDS-PAGE fragment from a TRAP-positive purification fraction. TRAP activity was also supported by hTR constructs lacking the box H/ACA small nucleolar RNA domain. End-point TRAP indicated expression levels within 3-fold of that from HeLa carcinoma cells, which is several orders of magnitude below detection by the direct assay. These results represent the first report of TRAP activity from a bacterium and provide a facile system for the investigation of assembly factors and anti-cancer therapeutics independently of a eukaryotic setting. PMID:26965413

  3. Surface recombination statistics at traps

    NASA Astrophysics Data System (ADS)

    Landsberg, P. T.; Abrahams, M. S.

    1983-09-01

    The Shockley-Read-Hall recombination statistics was recently generalised by Dhariwal, Kothari and Jain to include the effect of a finite time of relaxation before the captured carrier settles into its ground state, and by Landsberg to allow for Auger effects and so-called "extra" carriers supplied to the semiconductor from the outside. The combined result of these effects is studied here theoretically, together with the consideration of a simple distribution of trap states. It is found that the surface recombination velocity s has the usual minimum in the near intrinsic state and that s passes through a maximum as a function of excess electron concentration. Both extrema are enhanced if the trap states are distributed over an energy range. Experimental plots of s as a function of excess electron and hole concentrations should yield insight concerning the numerical importance of (a) Auger effects with the participation of traps and (b) relaxation times.

  4. Seismic fault zone trapped noise

    NASA Astrophysics Data System (ADS)

    Hillers, G.; Campillo, M.; Ben-Zion, Y.; Roux, P.

    2014-07-01

    Systematic velocity contrasts across and within fault zones can lead to head and trapped waves that provide direct information on structural units that are important for many aspects of earthquake and fault mechanics. Here we construct trapped waves from the scattered seismic wavefield recorded by a fault zone array. The frequency-dependent interaction between the ambient wavefield and the fault zone environment is studied using properties of the noise correlation field. A critical frequency fc ≈ 0.5 Hz defines a threshold above which the in-fault scattered wavefield has increased isotropy and coherency compared to the ambient noise. The increased randomization of in-fault propagation directions produces a wavefield that is trapped in a waveguide/cavity-like structure associated with the low-velocity damage zone. Dense spatial sampling allows the resolution of a near-field focal spot, which emerges from the superposition of a collapsing, time reversed wavefront. The shape of the focal spot depends on local medium properties, and a focal spot-based fault normal distribution of wave speeds indicates a ˜50% velocity reduction consistent with estimates from a far-field travel time inversion. The arrival time pattern of a synthetic correlation field can be tuned to match properties of an observed pattern, providing a noise-based imaging tool that can complement analyses of trapped ballistic waves. The results can have wide applicability for investigating the internal properties of fault damage zones, because mechanisms controlling the emergence of trapped noise have less limitations compared to trapped ballistic waves.

  5. Trapping Single Molecules by Dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Hölzel, Ralph; Calander, Nils; Chiragwandi, Zackary; Willander, Magnus; Bier, Frank F.

    2005-09-01

    We have trapped single protein molecules of R-phycoerythrin in an aqueous solution by an alternating electric field. A radio frequency voltage is applied to sharp nanoelectrodes and hence produces a strong electric field gradient. The resulting dielectrophoretic forces attract freely diffusing protein molecules. Trapping takes place at the electrode tips. Switching off the field immediately releases the molecules. The electric field distribution is computed, and from this the dielectrophoretic response of the molecules is calculated using a standard polarization model. The resulting forces are compared to the impact of Brownian motion. Finally, we discuss the experimental observations on the basis of the model calculations.

  6. Salisbury hospital's steam trap success.

    PubMed

    Baillie, Jonathan

    2011-03-01

    With the Carbon Reduction Commitment now fully in force, and the NHS tasked with achieving tough carbon emission reduction targets in line with both UK and EU mandates, healthcare estates teams across the country are seeking cost-effective ways to reduce energy consumption. Against this backdrop, Salisbury District Hospital has implemented a concerted energy-saving programme, key elements of which include replacing existing bucket steam traps with higher performing, lower maintenance, and more effective GEM venturi steam traps from Thermal Energy International (TEI), installing a new gas CHP engine, and looking into fitting a TEI condensate economiser system. PMID:21485315

  7. Dysprosium magneto-optical traps

    SciTech Connect

    Youn, Seo Ho; Lu Mingwu; Ray, Ushnish; Lev, Benjamin L.

    2010-10-15

    Magneto-optical traps (MOTs) of highly magnetic lanthanides open the door to explorations of novel phases of strongly correlated matter such as lattice supersolids and quantum liquid crystals. We recently reported the first MOTs of the five high-abundance isotopes of the most magnetic atom, dysprosium. Described here are details of the experimental technique employed for repumper-free Dy MOTs containing up to half a billion atoms. Extensive characterization of the MOTs' properties--population, temperature, loading, metastable decay dynamics, and trap dynamics--is provided.

  8. Organic Light-Emitting Devices with Tandem Structure.

    PubMed

    Chiba, Takayuki; Pu, Yong-Jin; Kido, Junji

    2016-06-01

    Tandem organic light-emitting devices (OLEDs) have attracted considerable attention for solid-state lighting and flat panel displays because their tandem architecture enables high efficiency and long operational lifetime simultaneously. In the tandem OLED structure, plural light-emitting units (LEUs) are stacked in series through a charge generation layer (CGL) and an electron injection layer (EIL). In this chapter, we focus on the key features of tandem OLEDs for high efficiency and long operational lifetimes. We also demonstrate the effect of the CGL comprising a Lewis acid, an n-type semiconductor metal oxide, and an organic electron-accepting material. We discuss the two types of EILs in tandem OLEDs: alkali metals containing n-type compounds and ultra-thin metals. Finally, we focus on the recent progress of the state-of-the-art solution-processed tandem OLEDs. PMID:27573273

  9. [Tandem repeats in rodents genome and their mapping].

    PubMed

    Ostromyshenskii, D I; Kuznetsova, L S; Komissarov, A S; Kartavtseva, I V; Podgornaya, L

    2015-01-01

    Tandemly-repeated sequences represent a unique class of eukaryotic DNA. Their content in the genome of higher eukaryotes mounts to tens of percents. However, the evolution of this class of sequences is poorly-studied. In our paper, 62 families of Mus musculus tandem repeats are analyzed by bioinformatic methods, and 7 of them are analyzed by fluorescence in situ hybridization. It is shown that the same tandem repeat sets co-occure only in closely related species of mice. But even in such species we observe differences in localization on the chromosomes and the number of individual tandem repeats. With increasing evolutionary distance only some of the tandem repeat families remain common for different species. It is shown, that the use of a combination of bioinformatics and molecular biology techniques is very perspective for further studies of the evolution of tandem repeats. PMID:26035967

  10. Potential of optical design in tandem micromorph silicon solar cells

    NASA Astrophysics Data System (ADS)

    Krc, J.; Campa, A.; Smole, F.; Topic, M.

    2006-04-01

    The potential of three advanced optical designs in tandem micromorph silicon solar cells are analysed by means of optical simulations: enhanced light scattering, intermediate reflector (interlayer) and antireflective coating (ARC) on glass. The effects on quantum efficiency, QE, and short circuit current density, J SC, of the top and bottom cell are investigated. In case of enhanced light scattering, the role of haze parameter and angular distribution function of scattered light is analysed separately. High haze parameter improves light trapping in top and bottom cell. However, the improvement in QE and J SC of the bottom cell is limited at higher haze parameters due to increased absorption in top cell and increased optical losses in realistic textured ZnO/Ag back contact. Broad ADF plays an important role for improving the performances of both, top and bottom cell. The role of refractive index of an interlayer between top and bottom cell is analysed. Significant increases in QE and J SC of the top cell are revealed for small refractive indexes of the interlayer (n < 2.0). At the same time noticeable decrease in the performance of the bottom cell is observed. Optimisation of thickness and refractive index of a single-layer ARC on glass is carried out in order to obtain maximal J SC either in top or in bottom cell. Moderate increases in J SC and QE are obtained for optimised ARC parameters. Among the three optical designs, the greatest potential, considering the improvements in both cells, is revealed for enhanced light scattering.

  11. A differentially pumped dual linear quadrupole ion trap (DLQIT) mass spectrometer: a mass spectrometer capable of MS(n) experiments free from interfering reactions.

    PubMed

    Owen, Benjamin C; Jarrell, Tiffany M; Schwartz, Jae C; Oglesbee, Rob; Carlsen, Mark; Archibold, Enada F; Kenttämaa, Hilkka I

    2013-12-01

    A novel differentially pumped dual linear quadrupole ion trap (DLQIT) mass spectrometer was designed and built to facilitate tandem MS experiments free from interfering reactions. The instrument consists of two differentially pumped Thermo Scientific linear quadrupole ion trap (LQIT) systems that have been connected via an ion transfer octupole encased in a machined manifold. Tandem MS experiments can be performed in the front trap and then the resulting product ions can be transferred via axial ejection into the back trap for further, independent tandem MS experiments in a differentially pumped area. This approach allows the examination of consecutive collision-activated dissociation (CAD) and ion-molecule reactions without unwanted side reactions that often occur when CAD and ion-molecule reactions are examined in the same space. Hence, it greatly facilitates investigations of ion structures. In addition, the overall lower pressure of the DLQIT, as compared to commercial LQIT instruments, results in a reduction of unwanted side reactions with atmospheric contaminants, such as water and oxygen, in CAD and ion-molecule experiments. PMID:24171553

  12. Cold atoms in videotape micro-traps

    NASA Astrophysics Data System (ADS)

    Sinclair, C. D. J.; Retter, J. A.; Curtis, E. A.; Hall, B. V.; Llorente Garcia, I.; Eriksson, S.; Sauer, B. E.; Hinds, E. A.

    2005-08-01

    We describe an array of microscopic atom traps formed by a pattern of magnetisation on a piece of videotape. We describe the way in which cold atoms are loaded into one of these micro-traps and how the trapped atom cloud is used to explore the properties of the trap. Evaporative cooling in the micro-trap down to a temperature of 1~μK allows us to probe the smoothness of the trapping potential and reveals some inhomogeneity produced by the magnetic film. We discuss future prospects for atom chips based on microscopic permanent-magnet structures.

  13. Microfabricated linear Paul-Straubel ion trap

    DOEpatents

    Mangan, Michael A.; Blain, Matthew G.; Tigges, Chris P.; Linker, Kevin L.

    2011-04-19

    An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

  14. Programmable trap geometries with superconducting atom chips

    SciTech Connect

    Mueller, T.; Fermani, R.; Zhang, B.; Chan, K. S.; Dumke, R.; Lim, M. J.

    2010-05-15

    We employ the hysteretic behavior of a superconducting thin film in the remanent state to generate different traps and flexible magnetic potentials for ultracold atoms. The trap geometry can be programed by externally applied fields. This approach for atom optics is demonstrated by three different trap types realized on a single microstructure: a Z-type trap, a double trap, and a bias-field-free trap. Our studies show that superconductors in the remanent state provide a versatile platform for atom optics and applications in ultracold quantum gases.

  15. Mass Trapping for Anastrepha suspensa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ABSTRACT In field tests conducted in south Florida to test grape juice as an alternative inexpensive bait for Anastrepha suspensa Loew, high numbers of Zaprionus indianus Gupta were captured in traps baited with aqueous grape juice. These experiments included comparisons of grape juice with standard...

  16. Acoustic trapping of active matter

    PubMed Central

    Takatori, Sho C.; De Dier, Raf; Vermant, Jan; Brady, John F.

    2016-01-01

    Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine self-propelled particles in two dimensions over distances large compared with the swimmers' run length. We develop a near-harmonic trap to demonstrate the crossover from weak confinement, where the probability density is Boltzmann-like, to strong confinement, where the density is peaked along the perimeter. At high concentrations the swimmers crystallize into a close-packed structure, which subsequently ‘explodes' as a travelling wave when the tweezer is turned off. The swimmers' confined motion provides a measurement of the swim pressure, a unique mechanical pressure exerted by self-propelled bodies. PMID:26961816

  17. Optical trapping in liquid crystals

    NASA Astrophysics Data System (ADS)

    Simoni, F.; Lucchetti, L.; Criante, L.; Bracalente, F.; Aieta, F.

    2010-08-01

    Optical trapping and manipulation of micrometric silica particles dispersed in a nematic liquid crystal is reported. Several kind of samples are considered: homeotropic and planar undoped cells and homeotropic and planar cells doped by a small amount of the azo-dye Methyl-Red. The incident light intensity is over the threshold for optical reorientation of the molecular director. The refractive index of the dispersed particles is lower than the ones of the liquid crystal therefore the usual conditions for laser trapping and manipulation are not fulfilled. Nevertheless optical trapping is possible and is closely related to the optical nonlinearity of the hosting liquid crystal1. Trapping in doped and undoped cells are compared and it is shown that in the first case intensity lower by more than one order of magnitude is required as compared to the one needed in undoped samples. The effect is faster and the structural forces are of longer range. The formation of bubble-gum like defects in doped samples under certain experimental conditions is also reported and discussed.

  18. A Death Trap for Microglia.

    PubMed

    Du, Xu-Fei; Du, Jiu-Lin

    2016-07-25

    Microglia, immune cells of the brain, originate from erythromyeloid precursors, far from the central nervous system. Xu et al. (2016) in this issue of Developmental Cell and Casano et al. (2016) recently in Cell Reports show that apoptotic neurons act as bait to "trap" microglia into colonizing the developing brain. PMID:27459061

  19. VACUUM TRAP AND VALVE COMBINATION

    DOEpatents

    Milleron, N.; Levenson, L.

    1963-02-19

    This patent relates to a vacuum trap and valve combination suitable for use in large ultra-high vacuum systems. The vacuum trap is a chamber having an inlet and outlet opening which may be made to communicate with a chamber to be evacuated and a diffusion pump, respectively. A valve is designed to hermeticaliy seal with inlet opening and, when opened, block the line-of- sight'' between the inlet and outlet openings, while allowing a large flow path between the opened vaive and the side walls of the trap. The interior of the trap and the side of the valve facing the inlet opening are covered with an impurity absorbent, such as Zeolite or activated aluminum. Besides the advantage of combining two components of a vacuum system into one, the present invention removes the need for a baffle between the pump and the chamber to be evacuated. In one use of a specific embodiment of this invention, the transmission probability was 45 and the partial pressure of the pump fluid vapor in the vacuum chamber was at least 100 times lower than its vapor pressure. (AEC)

  20. Isoelectronic Traps in Gallium Phosphide

    NASA Astrophysics Data System (ADS)

    Christian, Theresa; Alberi, Kirstin; Beaton, Daniel; Fluegel, Brian; Mascarenhas, Angelo

    2015-03-01

    Isoelectronic substitutional dopants can result in strongly localized exciton traps within a host bandstructure such as gallium arsenide (GaAs) or gallium phosphide (GaP). These traps have received great attention for their role in the anomalous bandgap bowing of nitrogen or bismuth-doped GaAs, creating the dramatic bandgap tunability of these unusual dilute alloys. In the wider, indirect-bandgap host material GaP, these same isoelectronic dopants create bound states within the gap that can have very high radiative efficiency and a wealth of discrete spectral transitions illuminating the symmetry of the localized excitonic trap state. We will present a comparative study of nitrogen and bismuth isoelectronic traps in GaP. Research was supported by the U. S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division under contract DE-AC36-08GO28308 and by the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF), made possible in part by the American Recovery and Reinvestment Act of 2009, administered by ORISE-ORAU under contract no. DE-AC05-06OR23100.

  1. The Trapped Medial Meniscus Tear

    PubMed Central

    Herschmiller, Thomas A.; Anderson, John A.; Garrett, William E.; Taylor, Dean C.

    2015-01-01

    Background: Numerous clinical examination maneuvers have been developed to identify meniscus tears of the knee. While meniscus injuries vary significantly in type and severity, no maneuvers have been developed that help to distinguish particular tear characteristics. Purpose: This nonconsecutive case series highlights a distinctive clinical finding that correlates with inferiorly displaced flap tears of the medial meniscus that become trapped in the medial gutter of the knee, as identified through magnetic resonance imaging (MRI) and arthroscopy. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Eight patients with trapped medial meniscus tears were identified from a single surgeon’s academic orthopaedic sports medicine practice between January 2009 and January 2012. Each patient underwent clinical evaluation, MRI, and arthroscopic treatment for meniscus injury. Clinical notes, MRI images, radiology reports, and operative findings were reviewed and compared in a descriptive fashion. Results: Each patient displayed a positive clinical examination finding of medial knee pain inferior to the joint line with flexion and the application of valgus stress in the setting of a torn medial meniscus and intact medial collateral ligament (MCL). Preoperative MRI revealed a distinctive flap tear of the medial meniscus flipped inferiorly to lay trapped between the tibia and deep fibers of the MCL. On arthroscopy, flap tears were found displaced inferiorly and trapped in the medial gutter in 6 of the 8 patients. Displaced meniscal fragments in the remaining 2 patients were found within the medial compartment. Conclusion: Inferiorly displaced flap tears of the meniscus that have been displaced to the medial gutter can be localized through a careful examination technique. Clinical Relevance: Early identification of this injury pattern may help reduce the likelihood that the trapped fragment will be missed during arthroscopy. PMID:26675499

  2. Optical sculpting: trapping through disorder and transfer of orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Cižmár, T.; Mazilu, M.; Dalgarno, H.; Ashok, P.; Gunn-Moore, F.; Dholakia, K.

    2011-03-01

    In this paper, we explore the propagation of light through disordered material and ask whether we can create an optimal focus in such a scenario. We use the complex modulation of the input light (i.e. modulation in both phase and amplitude) for these studies, implemented by use a spatial light modulator (SLM) and show trapping and manipulation through a static turbid medium. We then extend the system to create a tandem SLM system with an acousto-optic deflector. This has further advantages as we can now not only project light fields into turbid media but can also create interference-free mode superpositions of light fields such as Laguerre-Gaussian (LG) and Bessel modes. This is illustrated by controlled rotation of trapped particles in weighted, interference-free superpositions of LG beams of opposite order but equal magnitude.

  3. Funnel traps capture a higher proportion of juvenile Great Tits Parus major than automatic traps

    USGS Publications Warehouse

    Senar, J.C.; Domenech, J.; Conroy, M.J.

    1999-01-01

    We compared capture rates of Great Tits at funnel traps, where several birds can be captured at once so that some decoy effect may appear, to those obtained at automatic traps, where only one bird can be trapped at a time, at trapping stations in northeastern Spain. Juvenile birds were mainly captured at funnel traps (79% of juvenile captures), whereas adult plumaged birds were captured at both types of traps (51% of captures were at the funnel traps) (test between ages, P<0.001). Juvenile Great Tits had lower body condition as measured by ptilochronology (P<0.01). These birds are more easily trapped in funnel traps, which may be acting as decoy traps, and thus are vulnerable to the same kinds of biases (eg age or body condition) that have been previously documented for decoy traps.

  4. Tandem robot control system and method for controlling mobile robots in tandem

    DOEpatents

    Hayward, David R.; Buttz, James H.; Shirey, David L.

    2002-01-01

    A control system for controlling mobile robots provides a way to control mobile robots, connected in tandem with coupling devices, to navigate across difficult terrain or in closed spaces. The mobile robots can be controlled cooperatively as a coupled system in linked mode or controlled individually as separate robots.

  5. 50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Trap limits for vessels fishing or authorized to fish... management area designation certificate or valid limited access American lobster permit specifying one...

  6. 50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Trap limits for vessels fishing or authorized to fish... management area designation certificate or valid limited access American lobster permit specifying one...

  7. 50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Trap limits for vessels fishing or authorized to fish... management area designation certificate or valid limited access American lobster permit specifying one...

  8. 50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Trap limits for vessels fishing or authorized to fish... management area designation certificate or valid limited access American lobster permit specifying one...

  9. Flute waves in a tandem mirror

    SciTech Connect

    Mikhailovskaya, L.V.

    1984-03-01

    Stability conditions are derived for flute waves in a short tandem mirror stabilized by end cells with a min B. The frequency spectrum of the flute waves is analyzed. Those conditions under which the resonant excitation of waves by ions and electrons must be taken into account are found. When end cells without a min B are added to a central mirror system, the system becomes destabilized as the result of resonant excitation of waves at a frequency near the precession frequency of ions having a finite energy distribution.

  10. Reduction of radial losses in tandem mirrors

    NASA Astrophysics Data System (ADS)

    Myra, J. R.; Dippolito, D. A.; Catto, P. J.

    1982-07-01

    The conditions for omnigenous magnetic fields are generalized to determine the fields which give the smallest mean square neoclassical step size consistent with given boundary conditions and constraints. This transport minimization produces less restrictive field configurations than omnigenity, and a wider class of practical applications is possible. An explicit set of ordinary differential equations is obtained for the transport minimizing vacuum fields in long thin tandem mirror geometry. The constraint, for these configurations no parallel current flows into the center cell (due to the Stupakov effect), is imposed naturally.

  11. HRIBF Tandem Accelerator Radiation Safety System Upgrade

    SciTech Connect

    Blankenship, J.L.; Juras, R.C.

    1998-11-04

    The HRIBF Tandem Accelerator Radiation Safety System was designed to permit experimenters and operations staff controlled access to beam transport and experiment areas with accelerated beam present. Neutron-Gamma detectors are mounted in eaeh area at points of maximum dose rate and the resulting signals are integrated by redundan~ circuitry; beam is stopped if dose rate or integrated dose exceeds established limits. This paper will describe the system, in use for several vears at the HRIBF, and discuss changes recently made to modernize the system and to make the system compliant with DOE Order 5480.25 and related ORNL updated safety rules.

  12. A Hybrid Approach To Tandem Cylinder Noise

    NASA Technical Reports Server (NTRS)

    Lockard, David P.

    2004-01-01

    Aeolian tone generation from tandem cylinders is predicted using a hybrid approach. A standard computational fluid dynamics (CFD) code is used to compute the unsteady flow around the cylinders, and the acoustics are calculated using the acoustic analogy. The CFD code is nominally second order in space and time and includes several turbulence models, but the SST k - omega model is used for most of the calculations. Significant variation is observed between laminar and turbulent cases, and with changes in the turbulence model. A two-dimensional implementation of the Ffowcs Williams-Hawkings (FW-H) equation is used to predict the far-field noise.

  13. HRIBF Tandem Accelerator Radiation Safety System Upgrade

    NASA Astrophysics Data System (ADS)

    Juras, R. C.; Blankenship, J. L.

    1999-06-01

    The HRIBF Tandem Accelerator Radiation Safety System was designed to permit experimenters and operations staff controlled access to beam transport and experiment areas with accelerated beam present. Neutron-Gamma detectors are mounted in each area at points of maximum dose rate and the resulting signals are integrated by redundant circuitry; beam is stopped if dose rate or integrated dose exceeds established limits. This paper will describe the system, in use for several years at the HRIBF, and discuss changes recently made to modernize the system and to make the system compliant with DOE Order 5480.25 and related ORNL updated safety rules.

  14. Method of fabricating bifacial tandem solar cells

    SciTech Connect

    Wojtczuk, Steven J; Chiu, Philip T; Zhang, Xuebing; Gagnon, Edward; Timmons, Michael

    2014-10-07

    A method of fabricating on a semiconductor substrate bifacial tandem solar cells with semiconductor subcells having a lower bandgap than the substrate bandgap on one side of the substrate and with subcells having a higher bandgap than the substrate on the other including, first, growing a lower bandgap subcell on one substrate side that uses only the same periodic table group V material in the dislocation-reducing grading layers and bottom subcells as is present in the substrate and after the initial growth is complete and then flipping the substrate and growing the higher bandgap subcells on the opposite substrate side which can be of different group V material.

  15. The Naples University 3 MV tandem accelerator

    SciTech Connect

    Campajola, L.; Brondi, A.

    2013-07-18

    The 3 MV tandem accelerator of the Naples University is used for research activities and applications in many fields. At the beginning of operation (1977) the main utilization was in the field of nuclear physics. Later, the realization of new beam lines allowed the development of applied activities as radiocarbon dating, ion beam analysis, biophysics, ion implantation etc. At present, the availability of different ion sources and many improvements on the accelerator allow to run experiments in a wide range of subjects. An overview of the characteristics and major activities of the laboratory is presented.

  16. Fast quantitative detection of cocaine in beverages using nanoextractive electrospray ionization tandem mass spectrometry.

    PubMed

    Hu, Bin; Peng, Xuejiao; Yang, Shuiping; Gu, Haiwei; Chen, Huanwen; Huan, Yanfu; Zhang, Tingting; Qiao, Xiaolin

    2010-02-01

    Without any sample pretreatment, effervescent beverage fluids were manually sprayed into the primary ion plume created by using a nanoelectrospray ionization source for direct ionization, and the analyte ions of interest were guided into an ion trap mass spectrometer for tandem mass analysis. Functional ingredients (e.g., vitamins, taurine, and caffeine, etc.) and spiked impurity (e.g., cocaine) in various beverages, such as Red Bull energy drink, Coco-cola, and Pepsi samples were rapidly identified within 1.5 s. The limit of detection was found to be 7-15 fg (S/N = 3) for cocaine in different samples using the characteristic fragment (m/z 150) observed in the MS(3) experiments. Typical relative standard deviation and recovery of this method were 6.9%-8.6% and 104%-108% for direct analysis of three actual samples, showing that nanoextractive electrospray ionization tandem mass spectrometry is a useful technique for fast screening cocaine presence in beverages. PMID:19939702

  17. Collision-induced dissociation pathways of anabolic steroids by electrospray ionization tandem mass spectrometry.

    PubMed

    Guan, Fuyu; Soma, Lawrence R; Luo, Yi; Uboh, Cornelius E; Peterman, Scott

    2006-04-01

    Anabolic steroids are structurally similar compounds, and their product-ion spectra obtained by tandem mass spectrometry under electrospray ionization conditions are quite difficult to interpret because of poly-ring structures and lack of a charge-retaining center in their chemical structures. In the present study, the fragmentation of nine anabolic steroids of interest to the racing industry was investigated by using triple quadrupole mass spectrometer, Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer, and a linear ion trap instrument. With the aid of an expert system software (Mass Frontier version 3.0), accurate mass measurements, and multiple stage tandem mass spectrometric (MS(n)) experiments, fragmentation pathways were elucidated for boldenone, methandrostenolone, tetrahydrogestrinone (THG), trenbolone, normethandrolone and mibolerone. Small differences in the chemical structures of the steroids, such as an additional double-bond or a methyl group, result in significantly different fragmentation pathways. The fragmentation pathways proposed in this paper allow interpretation of major product ions of other anabolic steroids reported by other researchers in a recent publication. The proposed fragmentation pathways are helpful for characterization of new steroids. The approach used in this study for elucidation of the fragmentation pathways is helpful in interpretation of complicated product-ion spectra of other compounds, drugs and their metabolites. PMID:16488153

  18. Stokes Trap: Multiplexed particle trapping and manipulation using fluidics

    NASA Astrophysics Data System (ADS)

    Shenoy, Anish; Schroeder, Charles

    We report the development of the Stokes Trap, which is a multiplexed microfluidic trap for control over an arbitrary number of small particles in a microfluidic device. Our work involves the design and implementation of ``smart'' flow-based devices by coupling feedback control with microfluidics, thereby enabling new routes for the fluidic-directed assembly of particles. Here, we discuss the development of a new method to achieve multiplexed microfluidic trapping of an arbitrary number of particles using the sole action of fluid flow. In particular, we use a Hele-Shaw microfluidic cell to generate hydrodynamic forces on particles in a viscous-dominated flow defined by the microdevice geometry and imposed peripheral flow rates. This platform allows for a high degree of flow control over individual particles and can be used for manufacturing novel particles for fundamental studies, using fluidic-directed assembly. From a broader perspective, our work provides a solid framework for guiding the design of next-generation, automated on-chip assays.

  19. 50 CFR 697.27 - Trap transferability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Measures § 697.27 Trap transferability. (a) Federal lobster permit holders may elect to participate in a program that allows them to transfer trap allocation to other participating Federal lobster permit holders... Federal Trap Transfer Program: (i) An individual must possess a valid Federal lobster permit; and (ii)...

  20. Progress towards trapping of atomic hydrogen isotopes

    NASA Astrophysics Data System (ADS)

    Chavez, Isaac; Libson, Adam; Mazur, Tom; Majors, Julia; Raizen, Mark

    2009-05-01

    Using a series of pulsed electromagnetic coils (atomic coilgun) we can stop supersonic beams of paramagnetic atoms and molecules. We will employ the coilgun method to stop and trap supersonic beams of hydrogen isotopes. The slowed atoms will be trapped in a quadrupole magnetic trap where single-photon atomic cooling will be applied. Further applications will be discussed.

  1. An innovative mosquito trap for testing attractants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe a simple trap modification for testing or using attractants to collect flying mosquitoes. The trap also can test the effectiveness of spatial repellents. The proposed design may facilitate standardized testing of mosquito attractants and repellents. The trap uses a standard Centers f...

  2. 50 CFR 31.16 - Trapping program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Trapping program. 31.16 Section 31.16... NATIONAL WILDLIFE REFUGE SYSTEM WILDLIFE SPECIES MANAGEMENT Terms and Conditions of Wildlife Reduction and Disposal § 31.16 Trapping program. Except as hereafter noted, persons trapping animals on wildlife...

  3. Analysis of tandem mass spectra by FTMS for improved large-scale proteomics with superior protein quantification.

    PubMed

    McAlister, Graeme C; Phanstiel, Doug; Wenger, Craig D; Lee, M Violet; Coon, Joshua J

    2010-01-01

    Using a newly developed dual-cell quadrupole linear ion trap-orbitrap hybrid mass spectrometer (dcQLT-orbitrap), we demonstrate the utility of collecting high-resolution tandem mass spectral data for large-scale shotgun proteomics. Multiple nanoLC-MS/MS experiments on both an older generation quadrupole linear ion trap-orbitrap hybrid (QLT-orbitrap) and the dcQLT-orbitrap, using both resonant-excitation CAD and beam-type CAD (HCD), were performed. Resulting from various technological advances (e.g., a stacked ring ion guide AP inlet, a dual cell QLT), the dcQLT-orbitrap exhibited increased duty cycle (approximately 1.5-2 times) and sensitivity for both CAD (ion trap detection) and HCD (orbitrap detection) methods. As compared to the older system, the dcQLT-orbitrap produced significantly more unique peptide identifications for both methods (approximately 30% improvement for CAD and approximately 115% improvement for HCD). The sizable improvement of the HCD method on the dcQLT-orbitrap system outperforms the current standard method of CAD with ion trap detection for large-scale analysis. Finally, we demonstrate that the increased HCD performance translates to a direct and substantial improvement in protein quantitation precision using isobaric tags. PMID:19938823

  4. Analysis of tandem mass spectra by FTMS for improved large-scale proteomics with superior protein quantification

    PubMed Central

    McAlister, Graeme C.; Phanstiel, Doug; Wenger, Craig D.; Lee, M. Violet; Coon, Joshua J.

    2009-01-01

    Using a newly developed dual-cell quadrupole linear ion trap-orbitrap hybrid mass spectrometer (dcQLT-orbitrap), we demonstrate the utility of collecting high-resolution tandem mass spectral data for large-scale shotgun proteomics. Multiple nanoLC-MS/MS experiments on both an older generation quadrupole linear ion trap-orbitrap hybrid (QLT-orbitrap) and the dcQLT-orbitrap, using both resonant-excitation CAD and beam-type CAD (HCD) were performed. Resulting from various technological advances (e.g., a stacked ring ion guide AP inlet, a dual cell QLT, etc.), the dcQLT-orbitrap exhibited increased duty cycle (~1.5–2×) and sensitivity for both CAD (ion trap detection) and HCD (orbitrap detection) methods. As compared to the older system, the dcQLT-orbitrap produced significantly more unique peptide identification for both methods (~30% improvement for CAD and ~115% improvement for HCD). The sizeable improvement of the HCD method on the dcQLT-orbitrap system, outperforms the current standard method of CAD with ion trap detection for large-scale analysis. Finally, we demonstrate that the increased HCD performance translates to a direct and substantial improvement in protein quantitation precision using isobaric tags. PMID:19938823

  5. Progress in the tandem mirror program

    SciTech Connect

    Fowler, T.K.; Borchers, R.R.

    1981-09-13

    Experimental results in TMX have confirmed the basic principles of the tandem-mirror concept. A center-cell particle confinement parameter eta tau approx. 10/sup 11/ cm/sup -3/ s has been obtained at ion temperatures around 100 eV, which is a hundred-fold improvement over single mirrors at the same temperatures. For TMX these results have been obtained at peak beta values in the center cell in the range 10 to 40%, not yet limited by MHD activity; and ion-cyclotron resonant heating (ICRH) in the Phaedrus tandem-mirror experiment has produced beta values approx. 25%, which is several times the ideal MHD limit for that device. In addition, it has been demonstrated that the end fan chambers of TMX simultaneously isolate the hot electrons from the end walls, provide adequate pumping and conveniently dispose of the exhaust plasma energy either by thermal deposition on the end wall or by direct conversion to electricity (at 48% efficiency in agreement with calculations). Also, evidence was obtained for inherent divertor action in TMX, presumably in part responsible for the observed low impurity level (<0.5% low-Z ions in the center cell).

  6. Tandem mass spectrometry for sequencing proanthocyanidins.

    PubMed

    Li, Hui-Jing; Deinzer, Max L

    2007-02-15

    Proanthocyanidins (PAs) are a group of bioflavonoids consisting of oligomers based on catechin monomeric units. These polyphenolic compounds are widely distributed in higher plants and are an integral part of the human diet. A sensitive LC-tandem mass spectrometric (LC/ESI-MS(n)) method in the positive ion mode for sequencing these ubiquitous and highly beneficial antioxidants is described. The hydroxylation patterns and interflavanoid linkage for A- and B-type PAs were determined by fragment ions derived from a retro-Diels-Alder (RDA) fission, heterocyclic ring fission (HRF), a novel benzofuran-forming (BFF) fission described here for the first time, and a quinone methide (QM) fission. The subunit sequence of the PAs was determined by diagnostic ions derived from HRF/RDA fission, HRF/BFF fission, and RDA/HRF fission together with QM fission. A total of 26 PAs were reliably sequenced by the newly established tandem mass spectrometric protocol. It is shown that the protocol based on a combination of these different fragmentation patterns allows for uniquely identifying PA oligomers. PMID:17297981

  7. A tandem-based compact dual-energy gamma generator

    SciTech Connect

    Persaud, A.; Kwan, J.W.; Leitner, M.; Leung, K.N.; Ludewigt, B.; Tanaka, N.; Waldron, W.; Wilde, S.; Antolak, A.J.; Morse, D.H.; Raber, T.

    2009-11-11

    A dual-energy tandem-type gamma generator has been developed at E.O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications.

  8. High-sensitivity mass spectrometry with a tandem accelerator

    SciTech Connect

    Henning, W.

    1983-01-01

    The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems.

  9. Tandem-type pulse tube refrigerator without reservoir

    NASA Astrophysics Data System (ADS)

    Ki, Taekyung; Jeong, Sangkwon; Ko, Junseok; Park, Jiho

    2015-12-01

    In this paper, a tandem-type pulse tube refrigerator without a reservoir is discussed and investigated. For its practical application a tandem-type compressor is designed to generate two pulsating pressure waves with opposite phases, simultaneously. A tandem-type pulse tube refrigerator consists of a tandem-type compressor and two identical pulse tube refrigerators. The two identical pulse tube refrigerators share the same heat exchangers and one can be connected with the other by an inertance tube without a reservoir. In this proposed configuration, the mechanical vibration and temperature oscillations in the cold-end heat exchanger can be internally suppressed due to its intrinsic opposite-characteristic operation. To examine the quantitative evaluation of the tandem feature which does not require a reservoir in the pulse tube, an evolutionary approach has been attempted. A general structure of a pulse tube refrigerator is modified into tandem Stirling-type and GM-type machines and the transformed configuration has been simulated for tandem operation. The simulation results clearly demonstrate that a properly designed tandem-type pulse tube refrigerator without a reservoir can function favorably.

  10. Thermal-barrier production and indentification in a tandem mirror

    SciTech Connect

    Grubb, D.P.; Allen, S.L.; Casper, T.A.; Clauser, J.F.; Coensgen, F.H.; Correll, D.L.; Cummins, W.F.; Damm, C.C.; Foote, J.H.; Goodman, R.K.; Hill, D.N.; Hooper,Jr., E.B.; Hornady, R.S.; Hunt, A.L.; Kerr, R.G.; Leppelmeier, G.W.; Marilleau, J.; Moller, J.M.; Molvik, A.W.; Nexsen, W.E.; Pickles, W.L.; Porter, G.D.; Poulsen, P.; Silver, E.H.; Simonen, T.C.; Stallard, B.W.; Turner, W.C.; Hsu, W.L.; Yu, T.L.; Barter, J.D.; Christensen, T.; Dimonte, G.; Romesser, T.W.; Ellis, R.F.; James, R.A.; Lasnier, C.J.; Berzins, L.V.; Carter, M.R.; Clower, C.A.; Failor, B.H.; Falabella, S.; Flammer, M.; Nash, T.

    1984-08-20

    In thermal-barrier experiments in the tandem mirror experiment upgrade axial confinement times of 50 to 100 ms have been achieved. During enhanced confinement we measured the thermal-barrier potential profile using a neutral-particle-beam probe. The experimental data agree qualitatively and quantitatively with the theory of thermal-barrier formation in a tandem mirror.

  11. 14 CFR 105.45 - Use of tandem parachute systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Use of tandem parachute systems. 105.45... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES PARACHUTE OPERATIONS Parachute Equipment and Packing § 105.45 Use of tandem parachute systems. (a) No person may conduct a parachute operation using a...

  12. 14 CFR 105.45 - Use of tandem parachute systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Use of tandem parachute systems. 105.45... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES PARACHUTE OPERATIONS Parachute Equipment and Packing § 105.45 Use of tandem parachute systems. (a) No person may conduct a parachute operation using a...

  13. 14 CFR 105.45 - Use of tandem parachute systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Use of tandem parachute systems. 105.45... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES PARACHUTE OPERATIONS Parachute Equipment and Packing § 105.45 Use of tandem parachute systems. (a) No person may conduct a parachute operation using a...

  14. 14 CFR 105.45 - Use of tandem parachute systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Use of tandem parachute systems. 105.45... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES PARACHUTE OPERATIONS Parachute Equipment and Packing § 105.45 Use of tandem parachute systems. (a) No person may conduct a parachute operation using a...

  15. Microscale ion trap mass spectrometer

    DOEpatents

    Ramsey, J. Michael; Witten, William B.; Kornienko, Oleg

    2002-01-01

    An ion trap for mass spectrometric chemical analysis of ions is delineated. The ion trap includes a central electrode having an aperture; a pair of insulators, each having an aperture; a pair of end cap electrodes, each having an aperture; a first electronic signal source coupled to the central electrode; a second electronic signal source coupled to the end cap electrodes. The central electrode, insulators, and end cap electrodes are united in a sandwich construction where their respective apertures are coaxially aligned and symmetric about an axis to form a partially enclosed cavity having an effective radius r.sub.0 and an effective length 2z.sub.0, wherein r.sub.0 and/or z.sub.0 are less than 1.0 mm, and a ratio z.sub.0 /r.sub.0 is greater than 0.83.

  16. Extending dark optical trapping geometries.

    PubMed

    Arnold, Aidan S

    2012-07-01

    New counterpropagating geometries are presented for localizing ultracold atoms in the dark regions created by the interference of Laguerre-Gaussian laser beams. In particular dark helices, an "optical revolver," axial lattices of rings, and axial lattices of ring lattices of rings are considered and a realistic scheme for achieving phase stability is explored. The dark nature of these traps will enable their use as versatile tools for low-decoherence atom interferometry with zero differential light shifts. PMID:22743436

  17. Trapping waves in Earth's plasmasphere

    NASA Astrophysics Data System (ADS)

    Betz, Eric O.

    2014-12-01

    Earth's magnetic field traps donut-shaped bands of radiation in a belt around the planet that react to solar eruptions by growing and shrinking. The Van Allen belts consist of two rings filled with particles from the solar wind and cosmic rays. Within the outer ring of the Van Allen belt sits the plasmasphere, which is the innermost part of the planet's magnetic field and home to low-energy charged particles.

  18. Trapper readies trap for lizard

    NASA Technical Reports Server (NTRS)

    2000-01-01

    State-licensed animal trapper James Dean sets the open door of an animal trap on KSC. He hopes to catch a large monitor lizard spotted recently near S.R. 3, a route into the Center, by several area residents. The lizard is not a native of the area, and possibly a released pet. Dean is working with the cooperation of KSC and the Merritt Island National Wildlife Refuge.

  19. Lift enhancement by trapped vortex

    NASA Technical Reports Server (NTRS)

    Rossow, Vernon J.

    1992-01-01

    The viewgraphs and discussion of lift enhancement by trapped vortex are provided. Efforts are continuously being made to find simple ways to convert wings of aircraft from an efficient cruise configuration to one that develops the high lift needed during landing and takeoff. The high-lift configurations studied here consist of conventional airfoils with a trapped vortex over the upper surface. The vortex is trapped by one or two vertical fences that serve as barriers to the oncoming stream and as reflection planes for the vortex and the sink that form a separation bubble on top of the airfoil. Since the full three-dimensional unsteady flow problem over the wing of an aircraft is so complicated that it is hard to get an understanding of the principles that govern the vortex trapping process, the analysis is restricted here to the flow field illustrated in the first slide. It is assumed that the flow field between the two end plates approximates a streamwise strip of the flow over a wing. The flow between the endplates and about the airfoil consists of a spanwise vortex located between the suction orifices in the endplates. The spanwise fence or spoiler located near the nose of the airfoil serves to form a separated flow region and a shear layer. The vorticity in the shear layer is concentrated into the vortex by withdrawal of fluid at the suction orifices. As the strength of the vortex increases with time, it eventually dominates the flow in the separated region so that a shear or vertical layer is no longer shed from the tip of the fence. At that point, the vortex strength is fixed and its location is such that all of the velocity contributions at its center sum to zero thereby making it an equilibrium point for the vortex. The results of a theoretical analysis of such an idealized flow field are described.

  20. Search for tensor-like couplings in the β-decay of laser trapped 6He

    NASA Astrophysics Data System (ADS)

    Leredde, Arnaud; Bailey, Kevin; Mueller, Peter; O'Connor, Tom; Bagdasarova, Yelena; Garcia, Alejandro; Hong, Ran; Sternberg, Matthew; Storm, Derek; Swanson, Erik; Wauters, Frederik; Zumwalt, David; Flechard, Xavier; Naviliat-Cuncic, Oscar

    2015-10-01

    The beta-neutrino angular correlation in nuclear beta decay can reveal the nature of the weak interaction. The case of 6He is particularly sensitive to test for tensor contributions by measuring the corresponding angular correlation parameter aβν. Trapping techniques such as magneto-optical traps (MOT) combined with recoil ion momentum spectroscopy are powerful tools which allow to measure aβν with high precision. The experiment, located at the University of Washington, takes advantage of the tandem Van de Graaff accelerator to produce up to 2×1010 6He/s. A double-MOT setup has been optimized to trap and detect beta-recoil-ion coincidences at a rate of a few Hertz. Systematic effects have been investigated in details and major effort has been put to limit their contribution to less than 1% of aβν. The first goal of this experiment is to measure aβν with this 1% uncertainty and use this set of data to guide further improvements with the goal to bring the uncertainty to the 0.1% level. The performances of the trap setup, preliminary coincidence data, and studies of systematic uncertainties will be presented. This work is supported by DOE, Office of Nuclear Physics, under Contract Nos. DE-AC02-06CH11357 and DE-FG02-97ER41020.

  1. A new ion mobility-linear ion trap instrument for complex mixture analysis.

    PubMed

    Donohoe, Gregory C; Maleki, Hossein; Arndt, James R; Khakinejad, Mahdiar; Yi, Jinghai; McBride, Carroll; Nurkiewicz, Timothy R; Valentine, Stephen J

    2014-08-19

    A new instrument that couples a low-pressure drift tube with a linear ion trap mass spectrometer is demonstrated for complex mixture analysis. The combination of the low-pressure separation with the ion trapping capabilities provides several benefits for complex mixture analysis. These include high sensitivity, unique ion fragmentation capabilities, and high reproducibility. Even though the gas-phase separation and the mass measurement steps are each conducted in an ion filtering mode, detection limits for mobility-selected peptide ions are in the tens of attomole range. In addition to ion separation, the low-pressure drift tube can be used as an ion fragmentation cell yielding mobility-resolved fragment ions that can be subsequently analyzed by multistage tandem mass spectrometry (MS(n)) methods in the ion trap. Because of the ion trap configuration, these methods can be comprised of any number (limited by ion signal) of collision-induced dissociation (CID) and electron transfer dissociation (ETD) processes. The high reproducibility of the gas-phase separation allows for comparison of two-dimensional ion mobility spectrometry (IMS)-MS data sets in a pixel-by-pixel fashion without the need for data set alignment. These advantages are presented in model analyses representing mixtures encountered in proteomics and metabolomics experiments. PMID:25068446

  2. Deep trap, laser activated image converting system

    NASA Technical Reports Server (NTRS)

    Maserjian, J. (Inventor)

    1975-01-01

    Receiving an optical image on the surface of a photoconducting semiconductor is presented, storing the image in deep traps of the semiconductor, and later scanning the semiconductor with a laser beam to empty the deep traps, thereby producing a video signal. The semiconductor is illuminated with photons of energy greater than the band gap producing electron-hole pairs in the semiconductor which subsequently fill traps in energy from the band edges. When the laser beam of low energy photons excites the trapped electrons and holes out of the traps into the conduction and valence bands, a photoconductivity can be observed.

  3. Simple analytic potentials for linear ion traps

    NASA Technical Reports Server (NTRS)

    Janik, G. R.; Prestage, J. D.; Maleki, L.

    1989-01-01

    A simple analytical model was developed for the electric and ponderomotive (trapping) potentials in linear ion traps. This model was used to calculate the required voltage drive to a mercury trap, and the result compares well with experiments. The model gives a detailed picture of the geometric shape of the trapping potenital and allows an accurate calculation of the well depth. The simplicity of the model allowed an investigation of related, more exotic trap designs which may have advantages in light-collection efficiency.

  4. Simple analytic potentials for linear ion traps

    NASA Technical Reports Server (NTRS)

    Janik, G. R.; Prestage, J. D.; Maleki, L.

    1990-01-01

    A simple analytical model was developed for the electric and ponderomotive (trapping) potentials in linear ion traps. This model was used to calculate the required voltage drive to a mercury trap, and the result compares well with experiments. The model gives a detailed picture of the geometric shape of the trapping potential and allows an accurate calculation of the well depth. The simplicity of the model allowed an investigation of related, more exotic trap designs which may have advantages in light-collection efficiency.

  5. New ion trap for frequency standard applications

    NASA Technical Reports Server (NTRS)

    Prestage, J. D.; Dick, G. J.; Maleki, L.

    1989-01-01

    A novel linear ion trap was designed, which permits storage of a large number of ions with reduced susceptibility to the second-order Doppler effect caused by the RF confining fields. This new trap should store about 20 times the number of ions as a conventional RF trap with no corresponding increase in second-order Doppler shift from the confining field. In addition, the sensitivity of this shift to trapping parameters, i.e., RF voltage, RF frequency, and trap size, is greatly reduced.

  6. Electron trapping mechanisms in magnetron injection guns

    NASA Astrophysics Data System (ADS)

    Pagonakis, Ioannis Gr.; Piosczyk, Bernhard; Zhang, Jianhua; Illy, Stefan; Rzesnicki, Tomasz; Hogge, Jean-Philippe; Avramidis, Konstantinos; Gantenbein, Gerd; Thumm, Manfred; Jelonnek, John

    2016-02-01

    A key parameter for the gyrotron operation and efficiency is the presence of trapped electrons. Two electron trapping mechanisms can take place in gyrotrons: (i) the adiabatic trap and (ii) the magnetic potential well. Their influence on the gyrotron operation is analyzed. Two gun design criteria are then proposed to suppress both mechanisms in order to minimize the risk of possible problems. Experimental results of three high power gyrotrons are presented and their performance is correlated to the presence of populations of trapped electrons. Finally, some very general gun design principles are presented for the limitation of harmful electron trapping.

  7. A collapsible trap for capturing ruffe

    USGS Publications Warehouse

    Edwards, Andrew J.; Czypinski, Gary D.; Selgeby, James H.

    1998-01-01

    A modified version of the Windermere trap was designed, constructed, and tested for its effectiveness in capturing ruffe Gymnocephalus cernuus. The inexpensive, lightweight, collapsible trap was easily deployed and retrieved from a small boat. Field tests conducted at the St. Louis River estuary in western Lake Superior in spring 1995 and 1996 indicated that the trap was effective in capturing ruffe. Proportions of the ruffe in trap and bottom trawl catches were similar in 1995 and 1996. This trap could be a useful tool in surveillance, monitoring, or control programs for ruffe or similar species, either to augment existing sampling programs or especially in situations where gillnetting or bottom trawling are not feasible.

  8. The physiological effects of cycling on tandem and single bicycles

    PubMed Central

    Seifert, J; Bacharach, D; Burke, E; Langenfeld, M; Snyder, A

    2003-01-01

    Objective: The purpose of this field study was to compare the physiological responses from cycling on a tandem road bicycle to those from cycling on a single road bicycle. Methods: Nine pairs of experienced, recreational tandem cyclists rode a tandem or their single bicycle for 5 min at each velocity of 19.3, 22.5, 25.8, and 29.0 kph on a flat, paved surface. Heart rate (HR), rating of perceived exertion (RPE), and lactic acid (LA) data were collected after each interval. Results: Riding a tandem resulted in lower HR, RPE, and LA mean values across the four velocities compared to the single bicycle. Mean (SD) HR, RPE, and LA for tandem and single bicycles were 126 (20.7) v 142 (20.1) bpm, 10.1 (1.7) v 11.3 (2.6), and 1.46 (1.0) mM/L v 2.36 (1.7) mM/L, respectively. No position differences were observed between the captain and stoker (front and rear positions) when both were on the tandem. Stokers had significantly lower HR, LA, and RPE values when they rode a tandem compared to a single bicycle. No statistical differences were observed between bicycles for the captains. When on the single bicycle, captains exhibited significantly lower HR, RPE, and LA values than stokers. Conclusion: Cycling on a tandem resulted in lower physiological stress than when cycling at the same velocity on a single bicycle. Cyclists were able to ride from 4.8–8.0 kph faster on a tandem than on a single bicycle at similar physiological stress. Apparently, stokers can add to power output on a tandem without adding significantly to wind resistance. PMID:12547743

  9. Trapping a single atom in a blue detuned optical bottle beam trap.

    PubMed

    Xu, Peng; He, Xiaodong; Wang, Jin; Zhan, Mingsheng

    2010-07-01

    We demonstrate trapping a single rubidium atom in a blue detuned optical bottle beam trap. The trap was formed by a strongly focused blue detuned laser beam, which passes through a computer-generated circular pi phase hologram displayed on a spatial light modulator. Single atoms were loaded from a magneto-optical trap and stored in the optical trap for several seconds. PMID:20596181

  10. Efficacy of commercial traps and food odor attractants for mass trapping of Anastrepha ludens (Diptera: Tephritidae).

    PubMed

    Lasa, Rodrigo; Velázquez, Olinda E; Ortega, Rafael; Acosta, Emilio

    2014-02-01

    One of the most important factors for the success of a mass trapping strategy to control a fruit fly involves the selection of an effective trap-lure combination. Because different species of fruit flies respond differently to the physical characteristics of a trap and to bait volatiles, the evaluation of commercial traps and lures that have proved useful against other tephtrids is necessary to determine their efficacy for mass trapping of Anastrepha ludens (Loew) (Diptera: Tephritidae). Under caged conditions, a commercial hemispherical trap with lateral holes (Maxitrap Plus) proved more attractive to A. ludens (both sexes) than five other commercial traps that were all baited with hydrolyzed protein. Among these traps, bottom invaginated traps and traps with invaginated lateral holes constructed with transparent cylinders had the best physical retention properties. When evaluated under field conditions, the lure was critical for the efficacy of the trap, and one of the traps that performed poorly in attraction and retention cage tests (MS2) resulted as one of the most effective traps when baited with CeraTrap lure. Considering the use of different trap models under field conditions, CeraTrap liquid bait was more effective in A. ludens capture than Biolure dry synthetic bait, but both lures were not replaced during the entire course of the experiment. The percentage of captured females was also slightly higher using CeraTrap lure (67.2%) than using Biolure baits (54.5-58.8%). In field tests, 75-81% of females were mated and no significant differences were observed among trap-lure combinations. Trap selectivity against nontarget adult lacewings also differed among trap-lure combinations. PMID:24665702

  11. Electronic Tandem Language Learning (eTandem): A Third Approach to Second Language Learning for the 21st Century

    ERIC Educational Resources Information Center

    Cziko, Gary A.

    2004-01-01

    Tandem language learning occurs when two learners of different native languages work together to help each other learn the other language. First used in face-to-face contexts, Tandem is now increasingly being used by language-learning partners located in different countries who are linked via various forms of electronic communication, a context…

  12. AC electric trapping of neutral atoms

    NASA Astrophysics Data System (ADS)

    Marian, Adela; Schlunk, Sophie; Schoellkopf, Wieland; Meijer, Gerard

    2008-05-01

    We have demonstrated trapping of ultracold ground-state ^87Rb atoms in a macroscopic ac electric trap [1]. Trapping by ac electric fields has been previously achieved for polar molecules [2], as well as Sr atoms on a chip [3], and recently for Rb atoms in a three-phase electric trap [4]. Similar to trapping of ions in a Paul trap, three-dimensional confinement in an ac electric trap is obtained by switching between two saddle-point configurations of the electric field. For the first time, this dynamic confinement is directly visualized with absorption images taken at different phases of the ac switching cycle. Stable electric trapping is observed in a narrow range of switching frequencies around 60 Hz, in agreement with trajectory calculations. In a typical experiment, about 3 x 10^5 Rb atoms are trapped with lifetimes on the order of 9 s and trap depths of about 10 μK. Additionally, we show that the atoms can be used to sensitively probe the electric fields in the trap by imaging the cloud while the fields are still on. References: 1. S. Schlunk et al., PRL 98, 223002 (2007) 2. H. L. Bethlem et al., PRA 74, 063403 (2006) 3. T. Kishimoto et al., PRL 96, 123001 (2006) 4. T. Rieger et al., PRL 99, 063001 (2007)

  13. Ion traps fabricated in a CMOS foundry

    SciTech Connect

    Mehta, K. K.; Ram, R. J.; Eltony, A. M.; Chuang, I. L.; Bruzewicz, C. D.; Sage, J. M. Chiaverini, J.

    2014-07-28

    We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

  14. Evaluation of trapping-web designs

    USGS Publications Warehouse

    Lukacs, P.M.; Anderson, D.R.; Burnham, K.P.

    2005-01-01

    The trapping web is a method for estimating the density and abundance of animal populations. A Monte Carlo simulation study is performed to explore performance of the trapping web for estimating animal density under a variety of web designs and animal behaviours. The trapping performs well when animals have home ranges, even if the home ranges are large relative to trap spacing. Webs should contain at least 90 traps. Trapping should continue for 5-7 occasions. Movement rates have little impact on density estimates when animals are confined to home ranges. Estimation is poor when animals do not have home ranges and movement rates are rapid. The trapping web is useful for estimating the density of animals that are hard to detect and occur at potentially low densities. ?? CSIRO 2005.

  15. Temperature and trapping characterization of an acoustic trap with miniaturized integrated transducers--towards in-trap temperature regulation.

    PubMed

    Johansson, Linda; Evander, Mikael; Lilliehorn, Tobias; Almqvist, Monica; Nilsson, Johan; Laurell, Thomas; Johansson, Stefan

    2013-07-01

    An acoustic trap with miniaturized integrated transducers (MITs) for applications in non-contact trapping of cells or particles in a microfluidic channel was characterized by measuring the temperature increase and trapping strength. The fluid temperature was measured by the fluorescent response of Rhodamine B in the microchannel. The trapping strength was measured by the area of a trapped particle cluster counter-balanced by the hydrodynamic force. One of the main objectives was to obtain quantitative values of the temperature in the fluidic channel to ensure safe handling of cells and proteins. Another objective was to evaluate the trapping-to-temperature efficiency for the trap as a function of drive frequency. Thirdly, trapping-to-temperature efficiency data enables identifying frequencies and voltage values to use for in-trap temperature regulation. It is envisioned that operation with only in-trap temperature regulation enables the realization of small, simple and fast temperature-controlled trap systems. The significance of potential gradients at the trap edges due to the finite size of the miniaturized transducers for the operation was emphasized and expressed analytically. The influence of the acoustic near field was evaluated in FEM-simulation and compared with a more ideal 1D standing wave. The working principle of the trap was examined by comparing measurements of impedance, temperature increase and trapping strength with impedance transfer calculations of fluid-reflector resonances and frequencies of high reflectance at the fluid-reflector boundary. The temperature increase was found to be moderate, 7°C for a high trapping strength, at a fluid flow of 0.5mms(-1) for the optimal driving frequency. A fast temperature response with a fall time of 8s and a rise time of 11s was observed. The results emphasize the importance of selecting the proper drive frequency for long term handling of cells, as opposed to the more pragmatic way of selecting the

  16. Solar Energetic Particles Trapping in the Magnetosphere

    NASA Astrophysics Data System (ADS)

    Engel, M.; Larsen, B. A.

    2011-12-01

    Solar energetic particles (SEPs) are protons, electrons, and heavy ions emitted from the Sun with energies spanning tens of keV to GeV. They are episodic and associated with energetic events at the Sun such as coronal mass ejections. Importantly, they can be injected into and trapped by the Earth's magnetosphere, forming transient new, intense radiation belts that can severely damage components of our space infrastructure and cause significant backgrounds in instruments on national security and other payloads. Our goal is to understand the conditions under which SEPs become trapped and untrapped in the magnetosphere, how trapping depends on the energy distribution of the trapped particles, and if we can predict the location and persistence of these new radiation belts. Previous studies have shown how trapping can occur for individual shock-driven events but do not explore the overall magnetospheric conditions that can lead to SEP trapping and cannot predict trapped population energy spectra, location, or provide a probabilistic model trapping likelihood. Using events spanning 10 years, we will correlate the magnetospheric conditions that affect trapping and dumping. The results of this study will attempt to answer the questions: What fraction of injected SEPs are trapped,forming new, persistent radiation belts? Is there a geomagnetic field preconditioning required for injected SEPs to be trapped or untrapped? What does the energy distribution of injected SEPs relative to their trapped distribution tell us about the underlying physics of trapping? What is the probability of trapping injected SEPs based on different magnetospheric conditions, and can we use this probability as a predictive tool?

  17. Negative deuterium ions for tandem mirror next step and tandem mirror reactors

    SciTech Connect

    Hamilton, G.W.

    1980-09-25

    Recent designs for mirror fusion reactors with good power balance include ambipolar potential plugs to reduce end losses and thermal barriers to maintain a difference in electron temperature between the large-volume central cell plasma and the confining end plugs. These designs led to several new requirements for D/sup 0/ neutral beams derived from negative ions at energies of 150 to 200 keV and possibly higher. Such beams are required for injection of fat ions into the plugs and the barrier and for charge-exchange pumping of thermal ions diffusing into the barrier. Negative ions are preferred for these purposes because of their relatively high efficiency of neutralization and their high purity of single-energy D/sup -/. Examples of injector designs for Tandem Mirror Next Step (TMNS) and Tandem Mirror Reactors (TMR) are presented.

  18. III-V/silicon germanium tandem solar cells on silicon substrates

    NASA Astrophysics Data System (ADS)

    Schmieder, Kenneth J.

    concluding with a GaAsP/SiGe tandem device, is analyzed and reported. GaAsP bandgap-voltage offsets achieve a record best result of 0.54 Volts in single-junction devices while dual-junction devices demonstrate a result toward AM1.5 19.4% efficiency with AR-correction and light trapping.

  19. Parametric systems analysis for tandem mirror hybrids

    SciTech Connect

    Lee, J.D.; Chapin, D.L.; Chi, J.W.H.

    1980-09-01

    Fusion fission systems, consisting of fissile producing fusion hybrids combining a tandem mirror fusion driver with various blanket types and net fissile consuming LWR's, have been modeled and analyzed parametrically. Analysis to date indicates that hybrids can be competitive with mined uranium when U/sub 3/O/sub 8/ cost is about 100 $/lb., adding less than 25% to present day cost of power from LWR's. Of the three blanket types considered, uranium fast fission (UFF), thorium fast fission (ThFF), and thorium fission supressed (ThFS), the ThFS blanket has a modest economic advantage under most conditions but has higher support ratios and potential safety advantages under all conditions.

  20. Magnetic alignment of the Tara tandem mirror

    SciTech Connect

    Post, R.S.; Coleman, J.W.; Irby, J.H.; Olmstead, M.M.; Torti, R.P.

    1985-06-01

    Techniques developed for the alignment of high-energy accelerators have been applied to the alignment of the Tara tandem mirror magnetic confinement device. Tools used were: a transit/laser surveyor's system for establishing an invariant reference; optical scattering from ferromagnetic crystallites for establishing magnetic centers in the quadrupole anchor/transition modules; an electron-optical circle-generating wand for alignment of the solenoidal plug and central cell modules; and four differently configured electron emissive probes, including a 40-beam flux mapping e gun, for testing the alignment of the coils under vacuum. Procedures are outlined, and results are given which show that the magnetic axes of the individual coils in the Tara set have been made colinear with each other and with the reference to within +- 1.0 mm over the length of the machine between the anchor midplanes.

  1. Catalyzed deuterium fueled tandem mirror reactor assessment

    SciTech Connect

    Dobrott, D.

    1985-01-01

    This study was part of a Department of Energy supported alternate fusion fuels program at Science Applications International Corp. The purpose of this portion of the study is to perform an assessment of a conceptual tandem mirror reactor (TMR) that is fueled by the catalyzed-deuterium (Cat-d) fuel cycle with respect to the physics, technology, safety, and cost. Achievable stable betas and magnet configurations are found to be comparable for the Cat-d and d-t fueled TMR. A comparison with respect to cost, reactor performance, and technology requirements for a Cat-d fueled reactor and a comparable d-t fueled reactor such as MARS is also made.

  2. Electrospray and tandem mass spectrometry in biochemistry.

    PubMed Central

    Griffiths, W J; Jonsson, A P; Liu, S; Rai, D K; Wang, Y

    2001-01-01

    Over the last 20 years, biological MS has changed out of all recognition. This is primarily due to the development in the 1980s of 'soft ionization' methods that permit the ionization and vaporization of large, polar, and thermally labile biomolecules. These developments in ionization mode have driven the design and manufacture of smaller and cheaper mass analysers, making the mass spectrometer a routine instrument in the biochemistry laboratory today. In the present review the revolutionary 'soft ionization' methods will be discussed with particular reference to electrospray. The mass analysis of ions will be described, and the concept of tandem MS introduced. Where appropriate, examples of the application of MS in biochemistry will be provided. Although the present review will concentrate on the MS of peptides/proteins and lipids, all classes of biomolecules can be analysed, and much excellent work has been done in the fields of carbohydrate and nucleic acid biochemistry. PMID:11311115

  3. Dual analyte detection using tandem flash luminescence.

    PubMed

    Adamczyk, Maciej; Moore, Jeffrey A; Shreder, Kevin

    2002-02-11

    A heterogeneous, dual analyte-binding assay which makes use of the flash luminescence from both aequorin and an acridinium-9-carboxamide label is presented. The signal generating species were triggered both differentially and sequentially using Ca(2+) followed by basic peroxide. Both signals were resolved readily using a single photomultiplier tube without the need for multiwavelength detection. To demonstrate the tandem luminescence concept in a model assay system, dose-response curves for two analytes, biotinylated BSA and myoglobin, were generated using a competitive binding format. Because of the relatively short assay time and the well-resolved signals, this format will be useful in the development of dual analyte high-throughput assays. PMID:11814805

  4. Recent Results from KMAX tandem mirror experiment

    NASA Astrophysics Data System (ADS)

    Sun, Xuan; Luo, M.; Zhang, Q.; Lin, M.; Shi, P.

    2015-11-01

    KMAX, Keda Mirror with AXisymmeticity, is a tandem mirror machine with a length of ~ 10 meters and diameters of 1.2 meters in the central cell and 0.3 meters in the mirror throat. As a versatile plasma experimental platform, KMAX is currently conducting experiments on the Alfven wave launching, electrode biasing, radio frequency heating and etc. The latest results will be presented. In the experiment of Alfven wave launching, we observed the shear Alfven waves decay into the forward and backward propagating compressional waves. And in the bias experiment we successfully extracted plasma current up to 0.5kA with biasing voltage of ~ 1kV. During biasing, the plasma density and temperature have siginificantly increasing. Preliminary results on the radio frequency heating will also be presented.

  5. Protein Sequencing with Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ziady, Assem G.; Kinter, Michael

    The recent introduction of electrospray ionization techniques that are suitable for peptides and whole proteins has allowed for the design of mass spectrometric protocols that provide accurate sequence information for proteins. The advantages gained by these approaches over traditional Edman Degradation sequencing include faster analysis and femtomole, sometimes attomole, sensitivity. The ability to efficiently identify proteins has allowed investigators to conduct studies on their differential expression or modification in response to various treatments or disease states. In this chapter, we discuss the use of electrospray tandem mass spectrometry, a technique whereby protein-derived peptides are subjected to fragmentation in the gas phase, revealing sequence information for the protein. This powerful technique has been instrumental for the study of proteins and markers associated with various disorders, including heart disease, cancer, and cystic fibrosis. We use the study of protein expression in cystic fibrosis as an example.

  6. Status and outlook of CHIP-TRAP: The Central Michigan University high precision Penning trap

    NASA Astrophysics Data System (ADS)

    Redshaw, M.; Bryce, R. A.; Hawks, P.; Gamage, N. D.; Hunt, C.; Kandegedara, R. M. E. B.; Ratnayake, I. S.; Sharp, L.

    2016-06-01

    At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP) that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m / q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.

  7. Linear Ion Trap for the Mars Organic Molecule Analyzer

    NASA Astrophysics Data System (ADS)

    Brinckerhoff, William; Arevalo, Ricardo; Danell, Ryan; van Amerom, Friso; Pinnick, Veronica; Li, Xiang; Hovmand, Lars; Getty, Stephanie; Mahaffy, Paul; Goesmann, Fred; Steininger, Harald

    2014-05-01

    The 2018 ExoMars rover mission includes the Mars Organic Molecule Analyzer (MOMA) investigation. MOMA will examine the chemical composition of samples acquired from depths of up to two meters below the martian surface, where organics may be protected from radiative and oxidative degradation. When combined with the complement of instruments in the rover's Pasteur Payload, MOMA has the potential to reveal the presence of a wide range of organics preserved in a variety of mineralogical environments, and to begin to understand the structural character and potential origin of those compounds. MOMA includes a linear, or 2D, ion trap mass spectrometer (ITMS) that is designed to analyze molecular composition of (i) gas evolved from pyrolyzed powder samples and separated on a gas chromatograph and (ii) ions directly desorbed from solid samples at Mars ambient pressure using a pulsed laser and a fast-valve capillary ion inlet system. This "dual source" approach gives MOMA unprecedented breadth of detection over a wide range of molecular weights and volatilities. Analysis of nonvolatile, higher-molecular weight organics such as carboxylic acids and peptides even in the presence of significant perchlorate concentrations is enabled by the extremely short (~1 ns) pulses of the desorption laser. Use of the ion trap's tandem mass spectrometry mode permits selective focus on key species for isolation and controlled fragmentation, providing structural analysis capabilities. The flight-like engineering test unit (ETU) of the ITMS, now under construction, will be used to verify breadboard performance with high fidelity, while simultaneously supporting the development of analytical scripts and spectral libraries using synthetic and natural Mars analog samples guided by current results from MSL. ETU campaign data will strongly advise the specifics of the calibration applied to the MOMA flight model as well as the science operational procedures during the mission.

  8. The Composite Insect Trap: An Innovative Combination Trap for Biologically Diverse Sampling

    PubMed Central

    Russo, Laura; Stehouwer, Rachel; Heberling, Jacob Mason; Shea, Katriona

    2011-01-01

    Documentation of insect diversity is an important component of the study of biodiversity, community dynamics, and global change. Accurate identification of insects usually requires catching individuals for close inspection. However, because insects are so diverse, most trapping methods are specifically tailored to a particular taxonomic group. For scientists interested in the broadest possible spectrum of insect taxa, whether for long term monitoring of an ecosystem or for a species inventory, the use of several different trapping methods is usually necessary. We describe a novel composite method for capturing a diverse spectrum of insect taxa. The Composite Insect Trap incorporates elements from four different existing trapping methods: the cone trap, malaise trap, pan trap, and flight intercept trap. It is affordable, resistant, easy to assemble and disassemble, and collects a wide variety of insect taxa. Here we describe the design, construction, and effectiveness of the Composite Insect Trap tested during a study of insect diversity. The trap catches a broad array of insects and can eliminate the need to use multiple trap types in biodiversity studies. We propose that the Composite Insect Trap is a useful addition to the trapping methods currently available to ecologists and will be extremely effective for monitoring community level dynamics, biodiversity assessment, and conservation and restoration work. In addition, the Composite Insect Trap will be of use to other insect specialists, such as taxonomists, that are interested in describing the insect taxa in a given area. PMID:21698160

  9. War and the demographic trap.

    PubMed

    Last, J M

    1993-08-28

    Advice is offered on alleviating environmental damage and the suffering of women and children from the effects of war. It is postured that the demographic trap, which was described by King and Elliott, is responsible for environmental stress and many wars. The surface cause may be identified as ideology, politics, or ethnicity, but as in the case of Bosnia, the "ethnic cleansing" makes farmland available to sustain expanding Serbian or Croatian populations. If the land is environmentally damaged by war, then there is little hope of sustainable development. Conflicts in many countries have driven people to urban areas or periurban slums because of displacement and the failure of subsistence economics. Mortality from wars has reached more than a 100 million since the early 1990s. A comparable number have died indirectly from famine and disease associated with the disruption of agriculture and infrastructure from wars. Since 1945, 66-75% of mortality victims have been civilians, of whom 15 million have been women and children. In 1993, there were at least 30 conflicts ongoing throughout the world. Not all of these conflicts are as "ferocious" as the Bosnian conflict, but these "so called low intensity wars" nonetheless disrupt and kill. The manifestations of the demographic trap can be alleviated through interventions that focus on multisectoral aid and conflict resolution. There must be a cooperative effort on the part of health workers, agricultural scientists, mediators, and development personnel. Unfortunately, the amount of development assistance from Europe and America has been reduced in recent years. The recession has affected the provision of international aid. African nations, in particular, have been affected, yet these countries remain the neediest in the world. It would appear that aid agencies have given up hope that the demographic trap can be closed. Population growth must be limited, as the only hope for relieving environmental stress, ecological

  10. Electrokinetic trapping at the one nanometer limit

    PubMed Central

    Fields, Alexander P.; Cohen, Adam E.

    2011-01-01

    Anti-Brownian electrokinetic traps have been used to trap and study the free-solution dynamics of large protein complexes and long chains of DNA. Small molecules in solution have thus far proved too mobile to trap by any means. Here we explore the ultimate limits on trapping single molecules. We developed a feedback-based anti-Brownian electrokinetic trap in which classical thermal noise is compensated to the maximal extent allowed by quantum measurement noise. We trapped single fluorophores with a molecular weight of < 1 kDa and a hydrodynamic radius of 6.7 Å for longer than one second, in aqueous buffer at room temperature. This achievement represents an 800-fold decrease in the mass of objects trapped in solution, and opens the possibility to trap and manipulate any soluble molecule that can be fluorescently labeled. To illustrate the use of this trap, we studied the binding of unlabeled RecA to fluorescently labeled single-stranded DNA. Binding of RecA induced changes in the DNA diffusion coefficient, electrophoretic mobility, and brightness, all of which were measured simultaneously and on a molecule-by-molecule basis. This device greatly extends the size range of molecules that can be studied by room temperature feedback trapping, and opens the door to further studies of the binding of unmodified proteins to DNA in free solution. PMID:21562206

  11. Telomerase Repeated Amplification Protocol (TRAP)

    PubMed Central

    Mender, Ilgen; Shay, Jerry W.

    2016-01-01

    Telomeres are found at the end of eukaryotic linear chromosomes, and proteins that bind to telomeres protect DNA from being recognized as double-strand breaks thus preventing end-to-end fusions (Griffith et al., 1999). However, due to the end replication problem and other factors such as oxidative damage, the limited life span of cultured cells (Hayflick limit) results in progressive shortening of these protective structures (Hayflick and Moorhead, 1961; Olovnikov, 1973). The ribonucleoprotein enzyme complex telomerase-consisting of a protein catalytic component hTERT and a functional RNA component hTR or hTERC- counteracts telomere shortening by adding telomeric repeats to the end of chromosomes in ~90% of primary human tumors and in some transiently proliferating stem-like cells (Shay and Wright, 1996; Shay and Wright, 2001). This results in continuous proliferation of cells which is a hallmark of cancer. Therefore, telomere biology has a central role in aging, cancer progression/metastasis as well as targeted cancer therapies. There are commonly used methods in telomere biology such as Telomere Restriction Fragment (TRF) (Mender and Shay, 2015b), Telomere Repeat Amplification Protocol (TRAP) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this detailed protocol we describe Telomere Repeat Amplification Protocol (TRAP). The TRAP assay is a popular method to determine telomerase activity in mammalian cells and tissue samples (Kim et al., 1994). The TRAP assay includes three steps: extension, amplification, and detection of telomerase products. In the extension step, telomeric repeats are added to the telomerase substrate (which is actually a non telomeric oligonucleotide, TS) by telomerase. In the amplification step, the extension products are amplified by the polymerase chain reaction (PCR) using specific primers (TS upstream primer and ACX downstream primer) and in the detection step, the presence or absence of telomerase is

  12. Trapped iron measured on LDEF

    NASA Technical Reports Server (NTRS)

    Beaujean, R.; Jonathal, D.; Barz, S.; Enge, W.

    1995-01-01

    Heavy ions far below the cutoff energy were detected on the 28.5 deg inclination orbit of LDEF in a plastic track detector experiment. The Fe-group particles show a constant energy spectrum at 50 less than or equal to E less than or equal to 200 MeV/nuc. The steep energy spectrum of Fe-particles at 20 less than or equal to E less than or equal to 50 MeV/nuc and the arrival directions of these ions is consistent with a trapped component incident in the South Atlantic Anomaly at values of L=1.4-1.6.

  13. Introduced species as evolutionary traps

    USGS Publications Warehouse

    Schlaepfer, Martin A.; Sherman, P.W.; Blossey, B.; Runge, M.C.

    2005-01-01

    Invasive species can alter environments in such a way that normal behavioural decision-making rules of native species are no longer adaptive. The evolutionary trap concept provides a useful framework for predicting and managing the impact of harmful invasive species. We discuss how native species can respond to changes in their selective regime via evolution or learning. We also propose novel management strategies to promote the long-term co-existence of native and introduced species in cases where the eradication of the latter is either economically or biologically unrealistic.

  14. Laser trapping of radioactive atoms

    SciTech Connect

    Freedman, S.J.

    1995-04-01

    The capability of manipulating neutral atoms with the force of resonant scattered laser light is being exploited in several different areas of research. The author discusses applications in particle and nuclear physics by expediting some measurements of the subtle effects of the fundamental weak interaction in atoms and nuclei. It was shown in two recent experiments that it is possible to efficiently cool accelerator produced short-lived isotopes and load them into magneto-optic traps. These demonstrations open up new possibilities for obtaining the required precision in experiments involving rare radioactive isotopes.

  15. Gyrotactic trapping: A numerical study

    NASA Astrophysics Data System (ADS)

    Ghorai, S.

    2016-04-01

    Gyrotactic trapping is a mechanism proposed by Durham et al. ["Disruption of vertical motility by shear triggers formation of thin Phytoplankton layers," Science 323, 1067-1070 (2009)] to explain the formation of thin phytoplankton layer just below the ocean surface. This mechanism is examined numerically using a rational model based on the generalized Taylor dispersion theory. The crucial role of sedimentation speed in the thin layer formation is demonstrated. The effects of variation in different parameters on the thin layer formation are also investigated.

  16. Recent Activities in Tandem, Booster and TRIAC at Tokai

    SciTech Connect

    Ishii, Tetsuro; Matsuda, Makoto; Kabumoto, Hiroshi; Osa, Akihiko

    2009-05-04

    Present status and recent developments of the tandem accelerator, superconducting booster, and radioactive nuclear beam accelerator TRIAC are presented. The terminal voltage of the tandem accelerator reached 19.1 MV by replacing acceleration tubes. The multi-charged positive-ion injector was installed in the terminal of the tandem accelerator, supplying noble-gas ions. A superconducting cavity for low-velocity ions was developed. Radioactive nuclear beams of {sup 8}Li, {sup 123}In, and {sup 143}Ba were accelerated. Recent experimental results of nuclear physics are also reported.

  17. Classroom Tandem--Outlining a Model for Language Learning and Instruction

    ERIC Educational Resources Information Center

    Karjalainen, Katri; Pörn, Michaela; Rusk, Fredrik; Björkskog, Linda

    2013-01-01

    The aim of this paper is to outline classroom tandem by comparing it with informal tandem learning contexts and other language instruction methods. Classroom tandem is used for second language instruction in mixed language groups in the subjects of Finnish and Swedish as L2. Tandem learning entails that two persons with different mother tongues…

  18. 47 CFR 36.124 - Tandem switching equipment-Category 2.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Tandem switching equipment-Category 2. 36.124... Central Office Equipment § 36.124 Tandem switching equipment—Category 2. (a) Tandem switching equipment is contained in Accounts 2210, 2211, and 2212. It includes all switching equipment in a tandem central...

  19. Tandem Bond-Forming Reactions of 1-Alkynyl Ethers.

    PubMed

    Minehan, Thomas G

    2016-06-21

    Electron-rich alkynes, such as ynamines, ynamides, and ynol ethers, are functional groups that possess significant potential in organic chemistry for the formation of carbon-carbon bonds. While the synthetic utility of ynamides has recently been expanded considerably, 1-alkynyl ethers, which possess many of the reactivity features of ynamides, have traditionally been far less investigated because of concerns about their stability. Like ynamides, ynol ethers are relatively unhindered to approach by functional groups present in the same or different molecules because of their linear geometry, and they can potentially form up to four new bonds in a single transformation. Ynol ethers also possess unique reactivity features that make them complementary to ynamides. Research over the past decade has shown that ynol ethers formed in situ from stable precursors engage in a variety of useful carbon-carbon bond-forming processes. Upon formation at -78 °C, allyl alkynyl ethers undergo a rapid [3,3]-sigmatropic rearrangement to form allyl ketene intermediates, which may be trapped with alcohol or amine nucleophiles to form γ,δ-unsaturated carboxylic acid derivatives. The process is stereospecific, takes place in minutes at cryogenic temperatures, and affords products containing (quaternary) stereogenic carbon atoms. Trapping of the intermediate allyl ketene with carbonyl compounds, epoxides, or oxetanes instead leads to complex α-functionalized β-, γ-, or δ-lactones, respectively. [3,3]-Sigmatropic rearrangement of benzyl alkynyl ethers also takes place at temperatures ranging from -78 to 60 °C to afford substituted 2-indanones via intramolecular carbocyclization of the ketene intermediate. tert-Butyl alkynyl ethers containing pendant di- and trisubstituted alkenes and enol ethers are stable to chromatographic isolation and undergo a retro-ene/[2 + 2] cycloaddition reaction upon mild thermolysis (90 °C) to afford cis-fused cyclobutanones and donor

  20. Polaronic trapping in magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Raebiger, Hannes

    2012-02-01

    GaN doped with iron is an interesting candidate material for magnetic semiconductors, as p-d coupling between the localized Fe-d and extended N-p hole states is expected to facilitate long-range ferromagnetic alignment of the Fe spins [1]. This picture of extended states in GaN:Fe, however, falls apart due to a polaronic localization of the hole carriers nearby the Fe impurities. To elucidate the carrier localization in GaN:Fe and related iron doped III-V semiconductors, I present a systematic study using self-interaction corrected density-functional calculations [2]. These calculations predict three distinct scenarios. (i) Some systems do sustain extended host-like hole states, (ii) some exhibit polaronic trapping, (iii) and some exhibit carrier trapping at Fe-d orbitals. These behaviors are described in detail to give an insight as to how to distinguish them experimentally. I thank T. Fujita, C. Echeverria-Arrondo, and A. Ayuela for their collaboration.[4pt] [1] T. Dietl et al, Science, 287, 1019 (2000).[0pt] [2] S. Lany and A. Zunger, Phys. Rev. B, 80, 085202 (2009).

  1. Dielectrophoretic Traps for Single-Particle Patterning

    PubMed Central

    Rosenthal, Adam; Voldman, Joel

    2005-01-01

    We present a novel microfabricated dielectrophoretic trap designed to pattern large arrays of single cells. Because flowing away untrapped cells is often the rate-limiting step during cell patterning, we designed the trap to be strong enough to hold particles against practical flow rates. We experimentally validated the trap strength by measuring the maximum flow rate that polystyrene beads could withstand while remaining trapped. These bead experiments have shown excellent agreement with our model predictions, without the use of fitting parameters. The model was able to provide us with a fundamental understanding of how the traps work, and additionally allowed us to establish a set of design rules for optimizing the traps for a wide range of cell sizes. We provide the foundations for an enabling technology that can be used to pattern cells in unique ways, allowing us to do novel cell biology experiments at the microscale. PMID:15613624

  2. Trapping Rydberg Atoms in an Optical Lattice

    SciTech Connect

    Anderson, S. E.; Younge, K. C.; Raithel, G.

    2011-12-23

    Rubidium Rydberg atoms are laser excited and subsequently trapped in a one-dimensional optical lattice (wavelength 1064 nm). Efficient trapping is achieved by a lattice inversion immediately after laser excitation using an electro-optic technique. The trapping efficiency is probed via analysis of the trap-induced shift of the two-photon microwave transition 50S{yields}51S. The inversion technique allows us to reach a trapping efficiency of 90%. The dependence of the efficiency on the timing of the lattice inversion and on the trap laser power is studied. The dwell time of 50D{sub 5/2} Rydberg atoms in the lattice is analyzed using lattice-induced photoionization.

  3. Hydrogen-Trapping Mechanisms in Nanostructured Steels

    NASA Astrophysics Data System (ADS)

    Szost, B. A.; Vegter, R. H.; Rivera-Díaz-del-Castillo, Pedro E. J.

    2013-10-01

    Nanoprecipitation-hardened martensitic bearing steels (100Cr6) and carbide-free nanobainitic steels (superbainite) are examined. The nature of the hydrogen traps present in both is determined via the melt extraction and thermal desorption analysis techniques. It is demonstrated that 100Cr6 can admit large amounts of hydrogen, which is loosely bound to dislocations around room temperature; however, with the precipitation of fine coherent vanadium carbide traps, hydrogen can be immobilized. In the case of carbide-free nanostructured bainite, retained austenite/bainite interfaces act as hydrogen traps, while concomitantly retained austenite limits hydrogen absorption. In nanostructured steels where active hydrogen traps are present, it is shown that the total hydrogen absorbed is proportional to the trapped hydrogen, indicating that melt extraction may be employed to quantify trapping capacity.

  4. Improved Linear-Ion-Trap Frequency Standard

    NASA Technical Reports Server (NTRS)

    Prestage, John D.

    1995-01-01

    Improved design concept for linear-ion-trap (LIT) frequency-standard apparatus proposed. Apparatus contains lengthened linear ion trap, and ions processed alternately in two regions: ions prepared in upper region of trap, then transported to lower region for exposure to microwave radiation, then returned to upper region for optical interrogation. Improved design intended to increase long-term frequency stability of apparatus while reducing size, mass, and cost.

  5. Experiments in Planar Multipole Ion Traps

    NASA Astrophysics Data System (ADS)

    Clark, Rob; Burke, Timothy; Green, Dylan

    2016-05-01

    We present the design and demonstration of multipole ion traps based on concentric rings. We have developed both surface-electrode and layered planar trap designs which enable one to null the quadratic term in the electric potential to a high degree. Experiments demonstrating frequency upconversion of an applied signal demonstrate the nonlinear dynamics present in the trap. Applications include quantum chaos, ultracold chemistry, and, potentially, mass spectrometry. We acknowledge support from the Research Corporation for Science Advancement and from The Citadel Foundation.

  6. Trapping of intense light in hollow shell

    SciTech Connect

    Luan, Shixia; Yu, Wei; Yu, M. Y.; Weng, Suming; Wang, Jingwei; Xu, Han; Zhuo, Hongbin; Wong, A. Y.

    2015-09-15

    A small hollow shell for trapping laser light is proposed. Two-dimensional particle-in-cell simulation shows that under appropriate laser and plasma conditions a part of the radiation fields of an intense short laser pulse can enter the cavity of a small shell through an over-critical density plasma in an adjacent guide channel and become trapped. The trapped light evolves into a circulating radial wave pattern until its energy is dissipated.

  7. Active stabilization of ion trap radiofrequency potentials

    NASA Astrophysics Data System (ADS)

    Johnson, K. G.; Wong-Campos, J. D.; Restelli, A.; Landsman, K. A.; Neyenhuis, B.; Mizrahi, J.; Monroe, C.

    2016-05-01

    We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscillation frequency to be better than 10 Hz or 10 ppm. This represents a suppression of ambient noise on the rf circuit by 34 dB. This technique could impact the sensitivity of ion trap mass spectrometry and the fidelity of quantum operations in ion trap quantum information applications.

  8. Atomic Clock Based On Linear Ion Trap

    NASA Technical Reports Server (NTRS)

    Prestage, John D.; Dick, G. John

    1992-01-01

    Highly stable atomic clock based on excitation and measurement of hyperfine transition in 199Hg+ ions confined in linear quadrupole trap by radio-frequency and static electric fields. Configuration increases stability of clock by enabling use of enough ions to obtain adequate signal while reducing non-thermal component of motion of ions in trapping field, reducing second-order Doppler shift of hyperfine transition. Features described in NPO-17758 "Linear Ion Trap for Atomic Clock." Frequency standard based on hyperfine transition described in NPO-17456, "Trapped-Mercury-Ion Frequency Standard."

  9. Controlled rotation of optically trapped microscopic particles.

    PubMed

    Paterson, L; MacDonald, M P; Arlt, J; Sibbett, W; Bryant, P E; Dholakia, K

    2001-05-01

    We demonstrate controlled rotation of optically trapped objects in a spiral interference pattern. This pattern is generated by interfering an annular shaped laser beam with a reference beam. Objects are trapped in the spiral arms of the pattern. Changing the optical path length causes this pattern, and thus the trapped objects, to rotate. Structures of silica microspheres, microscopic glass rods, and chromosomes are set into rotation at rates in excess of 5 hertz. This technique does not depend on intrinsic properties of the trapped particle and thus offers important applications in optical and biological micromachines. PMID:11340200

  10. Ecological traps: current evidence and future directions

    PubMed Central

    Hale, Robin; Swearer, Stephen E.

    2016-01-01

    Ecological traps, which occur when animals mistakenly prefer habitats where their fitness is lower than in other available habitats following rapid environmental change, have important conservation and management implications. Empirical research has focused largely on assessing the behavioural effects of traps, by studying a small number of geographically close habitat patches. Traps, however, have also been defined in terms of their population-level effects (i.e. as preferred habitats of sufficiently low quality to cause population declines), and this is the scale most relevant for management. We systematically review the ecological traps literature to (i) describe the geographical and taxonomic distribution of efforts to study traps, (ii) examine how different traps vary in the strength of their effects on preference and fitness, (iii) evaluate the robustness of methods being used to identify traps, and (iv) determine whether the information required to assess the population-level consequences of traps has been considered. We use our results to discuss key knowledge gaps, propose improved methods to study traps, and highlight fruitful avenues for future research. PMID:26865295

  11. 5. GENERAL VIEW OF UNITEDTOD TWIN TANDEM STEAM ENGINE. ...

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

    5. GENERAL VIEW OF UNITED-TOD TWIN TANDEM STEAM ENGINE. - Republic Iron & Steel Company, Youngstown Works, Blooming Mill & Blooming Mill Engines, North of Poland Avenue, Youngstown, Mahoning County, OH

  12. SYMTRAN - A Time-dependent Symmetric Tandem Mirror Transport Code

    SciTech Connect

    Hua, D; Fowler, T

    2004-06-15

    A time-dependent version of the steady-state radial transport model in symmetric tandem mirrors in Ref. [1] has been coded up and first tests performed. Our code, named SYMTRAN, is an adaptation of the earlier SPHERE code for spheromaks, now modified for tandem mirror physics. Motivated by Post's new concept of kinetic stabilization of symmetric mirrors, it is an extension of the earlier TAMRAC rate-equation code omitting radial transport [2], which successfully accounted for experimental results in TMX. The SYMTRAN code differs from the earlier tandem mirror radial transport code TMT in that our code is focused on axisymmetric tandem mirrors and classical diffusion, whereas TMT emphasized non-ambipolar transport in TMX and MFTF-B due to yin-yang plugs and non-symmetric transitions between the plugs and axisymmetric center cell. Both codes exhibit interesting but different non-linear behavior.

  13. Argonne tandem as injector to a superconducting linac

    SciTech Connect

    Yntema, J.L.; Den Hartog, P.K.; Henning, W.; Kutschera, W.

    1980-01-01

    The Argonne Tandem uses Pelletron chains, NEC accelerator tubes, and a dual closed-corona system. Its main function is to be an injector for a superconducting linear accelerator. As long as the transverse and longitudinal emittances are within the acceptance of the linac, the output beam quality of the tandem-linac system is essentially determined by the tandem. The sensitivity of the linac to the longitudinal emittance ..delta..E..delta..t of the incident beam makes the output beam quality dependent on the negative-ion velocity distribution in the source, transit-time effects in the tandem, molecular-beam dissociation, and stripper-foil uniformity. This paper discusses these beam-degrading effects.

  14. D STAND DELIVERY END OF #44 TANDEM BREAKDOWN MILL WITH ...

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

    D STAND DELIVERY END OF #44 TANDEM BREAKDOWN MILL WITH UPCOILER. BACKUP ROLLS, 40 TONS. WORK ROLLS, 20 TONS., C. 1900. OPERATING SPEED, 600'/MINUTE. AUTOMATIC GAUGE CONTROL. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  15. Plasma-wall interactions in tandem mirror machines

    SciTech Connect

    Allen, S.L.

    1984-11-01

    A description is presented of the plasma-surface interactions in thermal-barrier tandem-mirror machines. The thermal-barrier mode of axial confinement is an integral part of a tandem mirror, and it dictates the required plasma conditions, particularly at the surface of the plasma. For this reason, a qualitative discussion of the thermal barrier is presented first in Section 2. A brief description of the experimental configuration used in tandem mirrors to create the thermal barrier is then examined in detail in Section 3; the TMX-U and MFTF-B machines are used as specific examples. In Section 4, the relevant plasma-surface interaction issues are addressed, and experimental results from currently operating tandom mirror machines are included. Section 5 is both a summary and a discussion of future work concerned with plasma-surface interactions in tandem mirrors.

  16. Patterns of tandem repetition in plant whole genome assemblies.

    PubMed

    Navajas-Pérez, Rafael; Paterson, Andrew H

    2009-06-01

    Tandem repeats often confound large genome assemblies. A survey of tandemly arrayed repetitive sequences was carried out in whole genome sequences of the green alga Chlamydomonas reinhardtii, the moss Physcomitrella patens, the monocots rice and sorghum, and the dicots Arabidopsis thaliana, poplar, grapevine, and papaya, in order to test how these assemblies deal with this fraction of DNA. Our results suggest that plant genome assemblies preferentially include tandem repeats composed of shorter monomeric units (especially dinucleotide and 9-30-bp repeats), while higher repetitive units pose more difficulties to assemble. Nevertheless, notwithstanding that currently available sequencing technologies struggle with higher arrays of repeated DNA, major well-known repetitive elements including centromeric and telomeric repeats as well as high copy-number genes, were found to be reasonably well represented. A database including all tandem repeat sequences characterized here was created to benefit future comparative genomic analyses. PMID:19242726

  17. Heavy-ion injection from tandems into an isochronous cyclotron

    SciTech Connect

    LeVine, M.J.; Chasman, C.

    1981-01-01

    A design has been realized for the injection of heavy ion beams generated by the BNL 3-stage tandem facility into a proposed isochronous cyclotron. The tandem beams are bunched into +- 1/sup 0/ R.F. phase (less than or equal to 0.5 nsec) in two stages. The beam is then injected into the cyclotron through a valley, past a hill, and into the next valley on to a stripper foil. Only a single steerer is required to make trajectory corrections for the different beams. Two achromats are used to regulate the tandem potential and to provide phase control. A final section of the injection optics provides matching of transverse phase space to the acceptance of the cyclotron. The calculations use realistic tandem emittances and magnetic fields for the cyclotron based on measurements with a model magnet.

  18. NTRFinder: a software tool to find nested tandem repeats.

    PubMed

    Matroud, Atheer A; Hendy, M D; Tuffley, C P

    2012-02-01

    We introduce the software tool NTRFinder to search for a complex repetitive structure in DNA we call a nested tandem repeat (NTR). An NTR is a recurrence of two or more distinct tandem motifs interspersed with each other. We propose that NTRs can be used as phylogenetic and population markers. We have tested our algorithm on both real and simulated data, and present some real NTRs of interest. NTRFinder can be downloaded from http://www.maths.otago.ac.nz/~aamatroud/. PMID:22121222

  19. Optimizing Trap Design and Trapping Protocols for Drosophila suzukii (Diptera: Drosophilidae).

    PubMed

    Renkema, Justin M; Buitenhuis, Rosemarije; Hallett, Rebecca H

    2014-12-01

    Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a recent invasive pest of fruit crops in North America and Europe. Carpophagous larvae render fruit unmarketable and may promote secondary rot-causing organisms. To monitor spread and develop programs to time application of controls, further work is needed to optimize trap design and trapping protocols for adult D. suzukii. We compared commercial traps and developed a new, easy-to-use plastic jar trap that performed well compared with other designs. For some trap types, increasing the entry area led to increased D. suzukii captures and improved selectivity for D. suzukii when populations were low. However, progressive entry area enlargement had diminishing returns, particularly for commercial traps. Unlike previous studies, we found putting holes in trap lids under a close-fitting cover improved captures compared with holes on sides of traps. Also, red and black traps outperformed yellow and clear traps when traps of all colors were positioned 10-15 cm apart above crop foliage. In smaller traps, attractant surface area and entry area, but not other trap features (e.g., headspace volume), appeared to affect D. suzukii captures. In the new, plastic jar trap, tripling attractant volume (360 vs 120 ml) and weekly attractant replacement resulted in the highest D. suzukii captures, but in the larger commercial trap these measures only increased by-catch of large-bodied Diptera. Overall, the plastic jar trap with large entry area is affordable, durable, and can hold high attractant volumes to maximize D. suzukii capture and selectivity. PMID:26470076

  20. Comparison of Trapping Performance Between the Original BG-Sentinel® Trap and BG-Sentinel 2® Trap (1).

    PubMed

    Arimoto, Hanayo; Harwood, James F; Nunn, Peter J; Richardson, Alec G; Gordon, Scott; Obenauer, Peter J

    2015-12-01

    Recently, the BG-Sentinel® trap (BGS) trap has been reconfigured for increased durability during harsh field conditions. We evaluated the attractiveness of this redesigned trap, BG-Sentinel 2® (BGS2), and its novel granular lure cartridge system relative to the original trap and lure. Granular lures containing different combinations of lactic acid, ammonia, hexanoic acid, and octenol were also evaluated. Lure cartridges with all components except octenol trapped significantly more Aedes albopictus than lures containing octenol. This new granular lure combination and original BG-Lure® system were paired with BGS and BGS2 traps to compare relative attractiveness of the lures and the traps. All evaluations were conducted under field conditions in a suburban neighborhood in northeastern Florida from July to October 2014. Overall, the average numbers of Ae. albopictus collected by BGS or BGS2 were similar regardless of the lure type (i.e., mesh bag versus granules) (P  =  0.56). The functionality and durability of both trap models are discussed. PMID:26675464

  1. Intragenic tandem repeat variation between Legionella pneumophila strains

    PubMed Central

    Coil, David A; Vandersmissen, Liesbeth; Ginevra, Christophe; Jarraud, Sophie; Lammertyn, Elke; Anné, Jozef

    2008-01-01

    Background Bacterial genomes harbour a large number of tandem repeats, yet the possible phenotypic effects of those found within the coding region of genes are only beginning to be examined. Evidence exists from other organisms that these repeats can be involved in the evolution of new genes, gene regulation, adaptation, resistance to environmental stresses, and avoidance of the immune system. Results In this study, we have investigated the presence and variability in copy number of intragenic tandemly repeated sequences in the genome of Legionella pneumophila, the etiological agent of a severe pneumonia known as Legionnaires' disease. Within the genome of the Philadelphia strain, we have identified 26 intragenic tandem repeat sequences using conservative selection criteria. Of these, seven were "polymorphic" in terms of repeat copy number between a large number of L. pneumophila serogroup 1 strains. These strains were collected from a wide variety of environments and patients in several geographical regions. Within this panel of strains, all but one of these seven genes exhibited statistically different patterns in repeat copy number between samples from different origins (environmental, clinical, and hot springs). Conclusion These results support the hypothesis that intragenic tandem repeats could play a role in virulence and adaptation to different environments. While tandem repeats are an increasingly popular focus of molecular typing studies in prokaryotes, including in L. pneumophila, this study is the first examining the difference in tandem repeat distribution as a function of clinical or environmental origin. PMID:19077205

  2. Resonance Trapping in Planetary Systems

    NASA Astrophysics Data System (ADS)

    Pour, Nader H.

    1998-09-01

    We study dynamics of a planetary system that consists of a star and two planets taking into account dynamical friction. Numerical integrations of a restricted planar circular three body model of this system indicate resonance capture. The main purpose of this paper is to present the results of an extensive numerical experiment performed on this model and also to present analytical arguments for the observed resonance trapping and its consequences. The equations of motion are written in terms of Delaunay variables and the recently developed method of partial averaging near resonance* is employed in order to account for the behavior of the system at resonance. * C.Chicone, B.Mashhoon and D.Retzloff, Ann.Inst.Henri Poincare, Vol.64, no 1, 1996, p.87-125.

  3. Dynamical Decoupling Using Trapped Ions

    NASA Astrophysics Data System (ADS)

    Biercuk, Michael; Uys, Hermann; Vandevender, Aaron; Shiga, Nobuyasu; Itano, Wayne; Bollinger, John

    2009-05-01

    We present a detailed experimental study of the Uhrig Dynamical Decoupling (UDD) sequence in a variety of noise environments. Our qubit system consists of a crystalline array of ^9Be^+ ions confined in a Penning trap. We use an electron-spin-flip transition as our qubit manifold and drive qubit rotations using a quasi-optical 124 GHz microwave system. We study the effect of the UDD sequence in mitigating phase errors and compare against the well-known CPMG-style spin echo as a function of pulse number, rotation axis, noise spectrum, and noise strength. Our results show good agreement with theoretical predictions for qubit decoherence in the presence of classical phase noise, accounting for the effect of finite-duration π pulses. Finally, we demonstrate that the Uhrig sequence is more robust against systematic over/underrotation and detuning errors than is multipulse spin echo, despite the precise prescription for pulse-timing in UDD.

  4. Comparison of Data Acquisition Strategies on Quadrupole Ion Trap Instrumentation for Shotgun Proteomics

    PubMed Central

    Canterbury, Jesse D.; Merrihew, Gennifer E.; Goodlett, David R.; MacCoss, Michael J.; Shaffer, Scott A.

    2015-01-01

    A common strategy in mass spectrometry analyses of complex protein mixtures is to digest the proteins to peptides, separate the peptides by microcapillary liquid chromatography and collect tandem mass spectra (MS/MS) on the eluting, complex peptide mixtures, a process commonly termed “shotgun proteomics”. For years, the most common way of data collection was via data-dependent acquisition (DDA), a process driven by an automated instrument control routine that directs MS/MS acquisition from the highest abundant signals to the lowest, a process often leaving lower abundant signals unanalyzed and therefore unidentified in the experiment. Advances in both instrumentation duty cycle and sensitivity allow DDA to probe to lower peptide abundance and therefore enable mapping proteomes to a more significant depth. An alternative to acquiring data by DDA is by data-independent acquisition (DIA), in which a specified range in m/z is fragmented without regard to prioritization of a precursor ion or its relative abundance in the mass spectrum. As a consequence, DIA acquisition potentially offers more comprehensive analysis of peptides than DDA and in principle can yield tandem mass spectra of all ionized molecules following their conversion to the gas-phase. In this work, we evaluate both DDA and DIA on three different linear ion trap instruments: an LTQ, an LTQ modified in-house with an electrodynamic ion funnel, and an LTQ-Velos. These instruments were chosen as they are representative of both older (LTQ) and newer (LTQ-Velos) ion trap designs i.e., linear ion trap and dual ion traps, respectively, and allow direct comparison of peptide identification using both DDA and DIA analysis. Further, as the LTQ-Velos has an improved “S-lens” ion guide in the high-pressure region to improve ion flux, we found it logical to determine if the former LTQ model could be leveraged by improving sensitivity by modifying with an electrodynamic ion guide of significantly different

  5. A toroidal trap for cold {}^{87}{Rb} atoms using an rf-dressed quadrupole trap

    NASA Astrophysics Data System (ADS)

    Chakraborty, A.; Mishra, S. R.; Ram, S. P.; Tiwari, S. K.; Rawat, H. S.

    2016-04-01

    We demonstrate the trapping of cold {}87{Rb} atoms in a toroidal geometry using a radio frequency (rf) dressed quadrupole magnetic trap formed by superposing a strong rf-field on a quadrupole trap. This rf-dressed quadrupole trap has the minimum potential away from the quadrupole trap centre on a circular path which facilitates trapping in toroidal geometry. In these experiments, the laser cooled atoms were first trapped in a quadrupole trap, then cooled evaporatively using a weak rf-field, and finally trapped in an rf-dressed quadrupole trap. The radius of the toroid could be varied by varying the frequency of the dressing rf-field. It has also been demonstrated that a single rf source and an antenna can be used for the rf-evaporative cooling as well as for the rf-dressing of atoms. The atoms trapped in the toroidal trap may have applications in the realization of an atom gyroscope as well as in studying the quantum gases in low dimensions.

  6. Quantum mechanics in rotating-radio-frequency traps and Penning traps with a quadrupole rotating field

    SciTech Connect

    Abe, K.; Hasegawa, T.

    2010-03-15

    Quantum-mechanical analysis of ion motion in a rotating-radio-frequency (rrf) trap or in a Penning trap with a quadrupole rotating field is carried out. Rrf traps were introduced by Hasegawa and Bollinger [Phys. Rev. A 72, 043404 (2005)]. The classical motion of a single ion in this trap is described by only trigonometric functions, whereas in the conventional linear radio-frequency (rf) traps it is by the Mathieu functions. Because of the simple classical motion in the rrf trap, it is expected that the quantum-mechanical analysis of the rrf traps is also simple compared to that of the linear rf traps. The analysis of Penning traps with a quadrupole rotating field is also possible in a way similar to the rrf traps. As a result, the Hamiltonian in these traps is the same as the two-dimensional harmonic oscillator, and energy levels and wave functions are derived as exact results. In these traps, it is found that one of the vibrational modes in the rotating frame can have negative energy levels, which means that the zero-quantum-number state (''ground'' state) is the highest energy state.

  7. How varying pest and trap densities affect Tribolium castaneum (Coleoptera: Tenebrionidae) capture in pheromone traps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is an important insect pest in food processing facilities. Pheromone trapping is frequently used to monitor red flour beetle populations in structures; however, the optimal trap density and the relationship between trap ...

  8. Light-trapping concentrator cells

    NASA Astrophysics Data System (ADS)

    Keavney, Christopher J.; Geoffroy, Leo M.; Sanfacon, Michael M.; Tobin, Stephen P.

    1989-11-01

    The objective was to develop a thin, light-trapping silicon concentrator solar cell using a new structure, the cross-grooved cell. A process was developed for fabricating V-grooves on both sides of thin silicon wafers, the grooves on one side being perpendicular to those on the other side. A way to minimize flat spots at the tops of the V-grooves was discovered. The theoretical light-trapping superiority of the cross-grooved structure was verified. A reduction was also demonstrated in grid line obscuration for grid lines running parallel to the V-grooves due to light reflection into the cell. High short-circuit current densities were achieved for p-i-n concentrator cells with the cross-grooved structure, proving the concept. The best efficiencies achieved were 18 percent at concentration, compared to 20 percent for a conventional planar low-resistivity cell. Recombination in the full-area emitter was identified as the major intrinsic loss mechanism in these thin, high-resistivity bifacial cells. Recombination on the emitter limits Voc and fill factor, and also leads to a large sublinearity of short-circuit current with light intensity. Reduction of the junction area is a major recommendation for future work. In addition, there were persistent problems with ohmic contacts and maintaining high minority-carrier lifetime during processing. It is believed that these problems can be solved, and that the cross-grooved cell is a viable approach to the limit-efficiency silicon solar cell. This report covers research conducted between March 1987 and July 1989.

  9. Software dependability in the Tandem GUARDIAN system

    NASA Technical Reports Server (NTRS)

    Lee, Inhwan; Iyer, Ravishankar K.

    1995-01-01

    Based on extensive field failure data for Tandem's GUARDIAN operating system this paper discusses evaluation of the dependability of operational software. Software faults considered are major defects that result in processor failures and invoke backup processes to take over. The paper categorizes the underlying causes of software failures and evaluates the effectiveness of the process pair technique in tolerating software faults. A model to describe the impact of software faults on the reliability of an overall system is proposed. The model is used to evaluate the significance of key factors that determine software dependability and to identify areas for improvement. An analysis of the data shows that about 77% of processor failures that are initially considered due to software are confirmed as software problems. The analysis shows that the use of process pairs to provide checkpointing and restart (originally intended for tolerating hardware faults) allows the system to tolerate about 75% of reported software faults that result in processor failures. The loose coupling between processors, which results in the backup execution (the processor state and the sequence of events) being different from the original execution, is a major reason for the measured software fault tolerance. Over two-thirds (72%) of measured software failures are recurrences of previously reported faults. Modeling, based on the data, shows that, in addition to reducing the number of software faults, software dependability can be enhanced by reducing the recurrence rate.

  10. Tandem-mirror technology demonstration facility

    SciTech Connect

    Fowler, T.K.; Logan, B.G.

    1981-09-18

    Preliminary calculations at LLNL indicate that a Technology Demonstration Facility (TDF) consisting of a tandem mirror machine about the size of TMX could begin providing fusion nuclear engineering data as early as 1988. With high density operation based on physics already demonstrated in TMX, this machine would produce 12 MW of DT neutrons in steady-state from a plasma column 0.08 m in radius and 8 m in length. Allowing space for neutral beam injectors at each end of the column, this would permit testing of blanket modules and components at 1 MW/m/sup 2/ neutron wall load over a cylindrical surface 8 m/sup 2/ in area at a radius of 0.25 m; or one could irradiate thousands of small samples at 2 MW/m/sup 2/ at r = 0.125 m (4 m/sup 2/ area). With improved end-plug physics to be tested in TMX-Upgrade in 1982-83, the wall load at 0.25 m could be increased to 2 MW/m/sup 2/ (4 MW/m/sup 2/ at r = 0.125 m). Construction of the TDF could begin in FY84 and be completed in 4 to 5 years, at a cost roughly estimated as $700M in '81 dollars including engineering and 30% contingency.

  11. Microcrystalline silicon and micromorph tandem solar cells

    NASA Astrophysics Data System (ADS)

    Keppner, H.; Meier, J.; Torres, P.; Fischer, D.; Shah, A.

    ``Micromorph'' tandem solar cells consisting of a microcrystalline silicon bottom cell and an amorphous silicon top cell are considered as one of the most promising new thin-film silicon solar-cell concepts. Their promise lies in the hope of simultaneously achieving high conversion efficiencies at relatively low manufacturing costs. The concept was introduced by IMT Neuchâtel, based on the VHF-GD (very high frequency glow discharge) deposition method. The key element of the micromorph cell is the hydrogenated microcrystalline silicon bottom cell that opens new perspectives for low-temperature thin-film crystalline silicon technology. According to our present physical understanding microcrystalline silicon can be considered to be much more complex and very different from an ideal isotropic semiconductor. So far, stabilized efficiencies of about 12% (10.7% independently confirmed) could be obtained with micromorph solar cells. The scope of this paper is to emphasize two aspects: the first one is the complexity and the variety of microcrystalline silicon. The second aspect is to point out that the deposition parameter space is very large and mainly unexploited. Nevertheless, the results obtained are very encouraging and confirm that the micromorph concept has the potential to come close to the required performance criteria concerning price and efficiency.

  12. Tandem mass spectrometry: analysis of complex mixtures

    SciTech Connect

    Singleton, K.E.

    1985-01-01

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

  13. Light Signaling Mechanism of Two Tandem Bacteriophytochromes

    PubMed Central

    Yang, Xiaojing; Stojković, Emina A.; Ozarowski, Wesley B.; Kuk, Jane; Davydova, Erna; Moffat, Keith

    2015-01-01

    RpBphP2 and RpBphP3, two tandem bacteriophytochromes from the photosynthetic bacterium R. palustris, share high sequence identity but exhibit distinct photoconversion behavior. Unlike the canonical RpBphP2, RpBphP3 photoconverts to an unusual nearred-absorbing (Pnr) state; both are required for synthesis of light harvesting complexes under low-light conditions. Here we report the crystal structures of the photosensory core modules of RpBphP2 and RpBphP3. Despite different quaternary structures, RpBphP2 and RpBphP3 adopt nearly identical tertiary structures. The RpBphP3 structure reveals “tongue-and-groove” interactions at the interface between the GAF and PHY domains. A single mutation in the PRxSF motif at the GAF-PHY interface abolishes light-induced formation of the Pnr state in RpBphP3, possibly due to altered structural rigidity of the chromophore-binding pocket. Structural comparisons suggest that long-range signaling involves structural rearrangement of the helical spine at the dimer interface. These structures together with mutational studies provide insights into photoconversion and long-range signaling mechanism in phytochromes. PMID:26095026

  14. Analysis of tandem mirror reactor performance

    SciTech Connect

    Wu, K.F.; Campbell, R.B.; Peng, Y.K.M.

    1984-11-01

    Parametric studies are performed using a tandem mirror plasma point model to evaluate the wall loading GAMMA and the physics figure of merit, Q (fusion power/injected power). We explore the relationship among several dominant parameters and determine the impact on the plasma performance of electron cyclotron resonance heating in the plug region. These global particle and energy balance studies were carried out under the constraints of magnetohydrodynamic (MHD) equilibrium and stability and constant magnetic flux, assuming a fixed end-cell geometry. We found that the higher the choke coil fields, the higher the Q, wall loading, and fusion power due to the combination of the increased central-cell field B/sub c/ and density n/sub c/ and the reduced central-cell beta ..beta../sub c/. The MHD stability requirement of constant B/sub c//sup 2/..beta../sub c/ causes the reduction in ..beta../sub c/. In addition, a higher value of fusion power can also be obtained, at a fixed central-cell length, by operating at a lower value of B/sub c/ and a higher value of ..beta../sub c/.

  15. Transcriptome annotation using tandem SAGE tags

    PubMed Central

    Rivals, Eric; Boureux, Anthony; Lejeune, Mireille; Ottones, Florence; Pecharromàn Pérez, Oscar; Tarhio, Jorma; Pierrat, Fabien; Ruffle, Florence; Commes, Thérèse; Marti, Jacques

    2007-01-01

    Analysis of several million expressed gene signatures (tags) revealed an increasing number of different sequences, largely exceeding that of annotated genes in mammalian genomes. Serial analysis of gene expression (SAGE) can reveal new Poly(A) RNAs transcribed from previously unrecognized chromosomal regions. However, conventional SAGE tags are too short to identify unambiguously unique sites in large genomes. Here, we design a novel strategy with tags anchored on two different restrictions sites of cDNAs. New transcripts are then tentatively defined by the two SAGE tags in tandem and by the spanning sequence read on the genome between these tagged sites. Having developed a new algorithm to locate these tag-delimited genomic sequences (TDGS), we first validated its capacity to recognize known genes and its ability to reveal new transcripts with two SAGE libraries built in parallel from a single RNA sample. Our algorithm proves fast enough to experiment this strategy at a large scale. We then collected and processed the complete sets of human SAGE tags to predict yet unknown transcripts. A cross-validation with tiling arrays data shows that 47% of these TDGS overlap transcriptional active regions. Our method provides a new and complementary approach for complex transcriptome annotation. PMID:17709346

  16. Engineering problems of tandem-mirror reactors

    SciTech Connect

    Moir, R.W.; Barr, W.L.; Boghosian, B.M.

    1981-10-22

    We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability. This paper discusses some of the many engineering problems facing the designer. We estimated the direct cost to be 2$/W/sub e/. Assuming total (direct and indirect) costs to be twice this number, we need to reduce total costs by factors between 1.7 and 2.3 to compete with future LWRs levelized cost of electricity. These reductions may be possible by designing magnets producing over 20T made possible by use of combinations of superconducting and normal conducting coils as well as improvements in performance and cost of neutral beam and microwave power systems. Scientific and technological understanding and innovation are needed in the area of thermal barrier pumping - a process by which unwanted particles are removed (pumped) from certain regions of velocity and real space in the end plug. Removal of exhaust fuel ions, fusion ash and impurities by action of a halo plasma and plasma dump in the mirror end region is another challenging engineering problem discussed in this paper.

  17. Characterisation by liquid chromatography-electrospray tandem mass spectrometry of anthocyanins in extracts of Myrtus communis L. berries used for the preparation of myrtle liqueur.

    PubMed

    Montoro, Paola; Tuberoso, Carlo I G; Perrone, Angela; Piacente, Sonia; Cabras, Paolo; Pizza, Cosimo

    2006-04-21

    Anthocyanins in extracts of berries of Myrtus communis, prepared following a typical Sardinia myrtle liqueur recipe, were identified and quantified by HPLC coupled with electrospray/tandem mass spectrometry using, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of the anthocyanidins were dependent on the MS technique employed, and differed considerably from those previously reported. The anthocyanin profile of five anthocyanin glucosides and four anthocyanin arabinosides, the latter not previously identified in this specie, was specific for myrtle berry extracts. The quantitative compositions of extracts of myrtle berries derived from different geographical areas in Italy were compared. PMID:16376912

  18. Trapped-Mercury-Ion Frequency Standard

    NASA Technical Reports Server (NTRS)

    Prestage, John D.; Dick, G. John; Maleki, Lutfollah

    1991-01-01

    Report describes principle of operation, design, and results of initial measurements on trapped-mercury-ion frequency-standard apparatus at NASA's Jet Propulsion Laboratory. New frequency standard being developed. Based on linear ion trap described in (NPO-17758). Expected to show much better short-term frequency stability because of increased ion-storage capacity.

  19. Compression of Antiproton Clouds for Antihydrogen Trapping

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Jenkins, M. J.; Joergensen, L. V.; Madsen, N.; Werf, D. P. van der; Bray, C. C.; Chapman, S.; Fajans, J.; Povilus, A.; Wurtele, J. S.; Cesar, C. L.; Lambo, R.; Silveira, D. M.; Fujiwara, M. C.; Gill, D. R.

    2008-05-23

    Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.

  20. 49 CFR 236.728 - Circuit, trap.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, trap. 236.728 Section 236.728... Circuit, trap. A term applied to a circuit used where it is desirable to provide a track circuit but where it is impracticable to maintain a track circuit....

  1. Cryptography, quantum computation and trapped ions

    SciTech Connect

    Hughes, Richard J.

    1998-03-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  2. FOAM PREVENTION IN PURGE AND TRAP ANALYSIS

    EPA Science Inventory

    Volatile organics are often separated from water samples by bubbling an inert gas through the water and collecting the organics on a sorbent trap, a technique known as purge and trap. Unfortunately, during the analysis of many water samples, foam can climb through the apparatus a...

  3. An Experimental Analysis of Social Traps

    ERIC Educational Resources Information Center

    Brechner, Kevin C.

    1977-01-01

    Social traps, such as the overgrazing of pasturelands, overpopulation, and the extinction of species, are situations where individuals in a group respond for their own advantage in a manner damaging to the group. Alaboratory analog was devised to simulate conditions that produce social traps. The intent was to cause an immediate positive…

  4. A CF4 based positron trap

    NASA Astrophysics Data System (ADS)

    Marjanovic, Srdjan; Bankovic, Ana; Dujko, Sasa; Deller, Adam; Cooper, Ben; Cassidy, David; Petrovic, Zoran

    2016-05-01

    All positron buffer gas traps in use rely on N2 as the primary trapping gas due to its conveniently placed a1 Π electronic excitation cross section that is large enough to compete with positronium (Ps) formation in the threshold region. Its energy loss of 8.5 eV is sufficient to capture positrons into a potential well upon a single collision. The competing Ps formation, however, limits the efficiency of the two stage trap to 25 %. As positron moderators produce beams with energies of several eV we have proposed to use CF4 in the first stage of the trap, due to its large vibrational excitation cross section, where several vibrational excitations would be sufficient to trap the positrons with small losses. Apart from the simulations we also report the results of attempts to apply this approach to an existing Surko-type positron trap. Operating the unmodified trap as a CF4 based device proved to be unsuccessful, due primarily to excessive scattering due to high CF4 pressure in the first stage. However, the performance was consistent with subsequent simulations using the real system parameters. This agreement indicates that an efficient CF4 based scheme may be realized in an appropriately designed trap. also at Serbian Academy of Sciences and Arts, Knez Mihajlova 35, 11000 Belgrade, Serbia.

  5. Evaluating the metapopulation consequences of ecological traps

    PubMed Central

    Hale, Robin; Treml, Eric A.; Swearer, Stephen E.

    2015-01-01

    Ecological traps occur when environmental changes cause maladaptive habitat selection. Despite their relevance to metapopulations, ecological traps have been studied predominantly at local scales. How these local impacts scale up to affect the dynamics of spatially structured metapopulations in heterogeneous landscapes remains unexplored. We propose that assessing the metapopulation consequences of traps depends on a variety of factors that can be grouped into four categories: the probability of encounter, the likelihood of selection, the fitness costs of selection and species-specific vulnerability to these costs. We evaluate six hypotheses using a network-based metapopulation model to explore the relative importance of factors across these categories within a spatial context. Our model suggests (i) traps are most severe when they represent a large proportion of habitats, severely reduce fitness and are highly attractive, and (ii) species with high intrinsic fitness will be most susceptible. We provide the first evidence that (iii) traps may be beneficial for metapopulations in rare instances, and (iv) preferences for natal-like habitats can magnify the effects of traps. Our study provides important insight into the effects of traps at landscape scales, and highlights the need to explicitly consider spatial context to better understand and manage traps within metapopulations. PMID:25761712

  6. Optical trapping map of dielectric spheres.

    PubMed

    Muradoglu, Murat; Ng, Tuck Wah

    2013-05-20

    Many applications use a focused Gaussian laser beam to manipulate spherical dielectric particles. The axial trapping efficiency of this process is a function of (i) the particle radius r, (ii) the ratio of the refractive index of particle over the medium, and (iii) the numerical aperture of the delivered light beam. During what we believe is the first comprehensive simulation of its kind, we uncovered optical trapping regions in the three-dimensional (3D) parameter space forming an iso-surface landscape with ridge-like contours. Using specific points in the parameter space, we drew attention to difficulties in using the trapping efficiency and stiffness metrics in defining how well particles are drawn into and held in the trap. We have proposed an alternative calculation based on the maximum forward and restoration values of the trapping efficiency in the axial sense, called the trapping quality. We also discuss the manner in which the ridge regions may be harnessed for effective particle sorting, how the optical trapping blind spots can be used in applications that seek to eschew photothermal damage, and how trapping can proceed when many parameters change, such as when swelling occurs. PMID:23736236

  7. Review of statistical analysis of trapped gas

    SciTech Connect

    Schmittroth, F.A.

    1996-03-19

    A review was conducted of trapped gas estimates in Hanford waste tanks. Tank waste levels were found to correlate with barometric pressure changes giving the possibility to infer amounts of trapped gas. Previous models of the tank waste level were extended to include other phenomena such as evaporation in a more complete description of tank level changes.

  8. Visual and olfactory enhancement of stable fly trapping

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the development of a less expensive and more efficacious trap based upon a white panel with the option for adding visual and olfactory stimuli for enhanced stable fly trapping. White panel traps caught more stable flies than Alsynite traps. Baiting the traps with synthetic manure volatiles...

  9. Enhanced trapping of stable flies via olfactory and visual cues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult stable flies are highly attracted to the so-called Alsynite cylinder trap; however this trap is expensive. Here we report the development of a cheaper and better white panel trap with options of adding visual and olfactory stimuli for enhanced stable fly trapping. The white panel trap attracte...

  10. Trapping the arboreal snake Boiga irregularis

    USGS Publications Warehouse

    Rodda, G.H.; Rondeau, R.J.; Fritts, T.H.; Maughan, O.E.

    1992-01-01

    The snake Boiga irregularis, an exotic on Guam, has eliminated the majority of the native vertebrates there. We tested traps designed to control this arboreal snake during three periods of 20-41 days in 1988 and 1989. The relative trapping successes with different baits and trap configurations indicated that this snake will not readily push through a visually obstructed entrance. However, under some conditions, 80% of the snakes escaped from traps lacking a physical blockage at the entrance. Live bait was more successful than odoriferous bait alone, and odoriferous guide ropes that led to trap entrances did not enhance capture rates. These findings corroborate laboratory experiments indicating an unusually strong dependence on visual cues in this highly successful nocturnal predator.

  11. New vanadium trap proven in commercial trials

    SciTech Connect

    Dougan, T.J. ); Alkemade, U.; Lakhanpal, B. ); Boock, L.T. )

    1994-09-26

    A vanadium trap technology called RV4+ has demonstrated in a variety of commercial fluid catalytic cracking (FCC) units its ability to reduce vanadium on equilibrium catalyst by more than 20%. Reducing vanadium loading increases microactivity and zeolite surface area retention, confirming that RV4+ protects zeolites from vanadium deactivation. Sulfur competition had prevented some previous traps from working commercially, but was not a factor with the new trap. The technology can save refiners millions of dollars per year in catalyst costs, or allow them to process feeds containing higher vanadium concentrations. The paper discusses vanadium traps, deactivation mechanism, history of traps, vanadium mobility, intraparticle mobility, interparticle mobility, measuring performance, commercial results, sulfur competition, and economic value.

  12. Trapping atoms using nanoscale quantum vacuum forces

    PubMed Central

    Chang, D. E.; Sinha, K.; Taylor, J. M.; Kimble, H. J.

    2014-01-01

    Quantum vacuum forces dictate the interaction between individual atoms and dielectric surfaces at nanoscale distances. For example, their large strengths typically overwhelm externally applied forces, which makes it challenging to controllably interface cold atoms with nearby nanophotonic systems. Here we theoretically show that it is possible to tailor the vacuum forces themselves to provide strong trapping potentials. Our proposed trapping scheme takes advantage of the attractive ground-state potential and adiabatic dressing with an excited state whose potential is engineered to be resonantly enhanced and repulsive. This procedure yields a strong metastable trap, with the fraction of excited-state population scaling inversely with the quality factor of the resonance of the dielectric structure. We analyse realistic limitations to the trap lifetime and discuss possible applications that might emerge from the large trap depths and nanoscale confinement. PMID:25008119

  13. Ion trap in a semiconductor chip

    NASA Astrophysics Data System (ADS)

    Stick, D.; Hensinger, W. K.; Olmschenk, S.; Madsen, M. J.; Schwab, K.; Monroe, C.

    2006-01-01

    The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ions. Work on miniaturizing electromagnetic traps to the micrometre scale promises even higher levels of control and reliability. Compared with `chip traps' for confining neutral atoms, ion traps with similar dimensions and power dissipation offer much higher confinement forces and allow unparalleled control at the single-atom level. Moreover, ion microtraps are of great interest in the development of miniature mass-spectrometer arrays, compact atomic clocks and, most notably, large-scale quantum information processors. Here we report the operation of a micrometre-scale ion trap, fabricated on a monolithic chip using semiconductor micro-electromechanical systems (MEMS) technology. We confine, laser cool and measure heating of a single 111Cd+ ion in an integrated radiofrequency trap etched from a doped gallium-arsenide heterostructure.

  14. A dynamical model for the Utricularia trap

    PubMed Central

    Llorens, Coraline; Argentina, Médéric; Bouret, Yann; Marmottant, Philippe; Vincent, Olivier

    2012-01-01

    We propose a model that captures the dynamics of a carnivorous plant, Utricularia inflata. This plant possesses tiny traps for capturing small aquatic animals. Glands pump water out of the trap, yielding a negative pressure difference between the plant and its surroundings. The trap door is set into a meta-stable state and opens quickly as an extra pressure is generated by the displacement of a potential prey. As the door opens, the pressure difference sucks the animal into the trap. We write an ODE model that captures all the physics at play. We show that the dynamics of the plant is quite similar to neuronal dynamics and we analyse the effect of a white noise on the dynamics of the trap. PMID:22859569

  15. Magneto-optical trap for thulium atoms

    SciTech Connect

    Sukachev, D.; Sokolov, A.; Chebakov, K.; Akimov, A.; Kanorsky, S.; Kolachevsky, N.; Sorokin, V.

    2010-07-15

    Thulium atoms are trapped in a magneto-optical trap using a strong transition at 410 nm with a small branching ratio. We trap up to 7x10{sup 4} atoms at a temperature of 0.8(2) mK after deceleration in a 40-cm-long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the magneto-optical trap which varies between 0.3 and 1.5 s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be 22(6) s{sup -1}. The repumping laser transferring the atomic population out of the F=3 hyperfine ground-state sublevel gives a 30% increase for the lifetime and the number of atoms in the trap.

  16. Micro-fabricated stylus ion trap.

    PubMed

    Arrington, Christian L; McKay, Kyle S; Baca, Ehren D; Coleman, Jonathan J; Colombe, Yves; Finnegan, Patrick; Hite, Dustin A; Hollowell, Andrew E; Jördens, Robert; Jost, John D; Leibfried, Dietrich; Rowen, Adam M; Warring, Ulrich; Weides, Martin; Wilson, Andrew C; Wineland, David J; Pappas, David P

    2013-08-01

    An electroformed, three-dimensional stylus Paul trap was designed to confine a single atomic ion for use as a sensor to probe the electric-field noise of proximate surfaces. The trap was microfabricated with the UV-LIGA technique to reduce the distance of the ion from the surface of interest. We detail the fabrication process used to produce a 150 μm tall stylus trap with feature sizes of 40 μm. We confined single, laser-cooled, (25)Mg(+) ions with lifetimes greater than 2 h above the stylus trap in an ultra-high-vacuum environment. After cooling a motional mode of the ion at 4 MHz close to its ground state ( = 0.34 ± 0.07), the heating rate of the trap was measured with Raman sideband spectroscopy to be 387 ± 15 quanta/s at an ion height of 62 μm above the stylus electrodes. PMID:24007096

  17. Truly trapped rainbow by utilizing nonreciprocal waveguides.

    PubMed

    Liu, Kexin; He, Sailing

    2016-01-01

    The concept of a "trapped rainbow" has generated considerable interest for optical data storage and processing. It aims to trap different frequency components of the wave packet at different positions permanently. However, all the previously proposed structures cannot truly achieve this effect, due to the difficulties in suppressing the reflection caused by strong intermodal coupling and distinguishing different frequency components simultaneously. In this article, we found a physical mechanism to achieve a truly "trapped rainbow" storage of electromagnetic wave. We utilize nonreciprocal waveguides under a tapered magnetic field to achieve this and such a trapping effect is stable even under fabrication disorders. We also observe hot spots and relatively long duration time of the trapped wave around critical positions through frequency domain and time domain simulations. The physical mechanism we found has a variety of potential applications ranging from wave harvesting and storage to nonlinearity enhancement. PMID:27453496

  18. Truly trapped rainbow by utilizing nonreciprocal waveguides

    NASA Astrophysics Data System (ADS)

    Liu, Kexin; He, Sailing

    2016-07-01

    The concept of a “trapped rainbow” has generated considerable interest for optical data storage and processing. It aims to trap different frequency components of the wave packet at different positions permanently. However, all the previously proposed structures cannot truly achieve this effect, due to the difficulties in suppressing the reflection caused by strong intermodal coupling and distinguishing different frequency components simultaneously. In this article, we found a physical mechanism to achieve a truly “trapped rainbow” storage of electromagnetic wave. We utilize nonreciprocal waveguides under a tapered magnetic field to achieve this and such a trapping effect is stable even under fabrication disorders. We also observe hot spots and relatively long duration time of the trapped wave around critical positions through frequency domain and time domain simulations. The physical mechanism we found has a variety of potential applications ranging from wave harvesting and storage to nonlinearity enhancement.

  19. Truly trapped rainbow by utilizing nonreciprocal waveguides

    PubMed Central

    Liu, Kexin; He, Sailing

    2016-01-01

    The concept of a “trapped rainbow” has generated considerable interest for optical data storage and processing. It aims to trap different frequency components of the wave packet at different positions permanently. However, all the previously proposed structures cannot truly achieve this effect, due to the difficulties in suppressing the reflection caused by strong intermodal coupling and distinguishing different frequency components simultaneously. In this article, we found a physical mechanism to achieve a truly “trapped rainbow” storage of electromagnetic wave. We utilize nonreciprocal waveguides under a tapered magnetic field to achieve this and such a trapping effect is stable even under fabrication disorders. We also observe hot spots and relatively long duration time of the trapped wave around critical positions through frequency domain and time domain simulations. The physical mechanism we found has a variety of potential applications ranging from wave harvesting and storage to nonlinearity enhancement. PMID:27453496

  20. Mapping two-dimension trapping potential of nanoparticles in an optical trap

    NASA Astrophysics Data System (ADS)

    Fu, Jinxin; Hu, Yi; Zhou, Liangcheng; Lim, Min Yao; Goleb, Melissa; Zhan, Qiwen; Ou-Yang, H. Daniel

    2013-06-01

    Combining confocal microscopy and optical tweezers, we map out the spatial distribution of the particle concentrations of quantum dots, fluorescent HIV pseudo virus particles and polystyrene nanospheres in an optical trap. By analyzing the Boltzmann distribution of local particle concentrations, we obtain the two-dimension single particle trapping potential profile at the center of the optical trap in the direction perpendicular to the beam propagation. We compare the trapping potential energies of pseudo HIV vesicles and same-sized polystyrene spheres. We also compare the trapping potential energy of polystyrene spheres of a focused Gaussian beam and two modes of cylindrical vector beams.

  1. Mass trapping with MosquiTRAPs does not reduce Aedes aegypti abundance

    PubMed Central

    Degener, Carolin Marlen; de Ázara, Tatiana Mingote Ferreira; Roque, Rosemary Aparecida; Rösner, Susanne; Rocha, Eliseu Soares Oliveira; Kroon, Erna Geessien; Codeço, Cláudia Torres; Nobre, Aline Araújo; Ohly, Jörg Johannes; Geier, Martin; Eiras, Álvaro Eduardo

    2015-01-01

    The objective of this study was to evaluate the effectiveness of Aedes aegypti mass trapping using the sticky trap MosquiTRAP (MQT) by performing a cluster randomised controlled trial in Manaus, state of Amazonas, Brazil. After an initial questionnaire and baseline monitoring of adult Ae. aegypti abundance with BG-Sentinel (BGS) traps in six clusters, three clusters were randomly assigned to the intervention arm where each participating household received three MQTs for mass trapping during 17 months. The remaining three clusters (control arm) did not receive traps. The effect of mass trapping on adult Ae. aegypti abundance was monitored fortnightly with BGS traps. During the last two months of the study, a serological survey was conducted. After the study, a second questionnaire was applied in the intervention arm. Entomological monitoring indicated that MQT mass trapping did not reduce adult Ae. aegypti abundance. The serological survey indicated that recent dengue infections were equally frequent in the intervention and the control arm. Most participants responded positively to questions concerning user satisfaction. According to the results, there is no evidence that mass trapping with MQTs can be used as a part of dengue control programs. The use of this sticky trap is only recommendable for dengue vector monitoring. PMID:25946154

  2. Mass trapping with MosquiTRAPs does not reduce Aedes aegypti abundance.

    PubMed

    Degener, Carolin Marlen; de Ázara, Tatiana Mingote Ferreira; Roque, Rosemary Aparecida; Rösner, Susanne; Rocha, Eliseu Soares Oliveira; Kroon, Erna Geessien; Codeço, Cláudia Torres; Nobre, Aline Araújo; Ohly, Jörg Johannes; Geier, Martin; Eiras, Álvaro Eduardo

    2015-06-01

    The objective of this study was to evaluate the effectiveness of Aedes aegypti mass trapping using the sticky trap MosquiTRAP (MQT) by performing a cluster randomised controlled trial in Manaus, state of Amazonas, Brazil. After an initial questionnaire and baseline monitoring of adult Ae. aegypti abundance with BG-Sentinel (BGS) traps in six clusters, three clusters were randomly assigned to the intervention arm where each participating household received three MQTs for mass trapping during 17 months. The remaining three clusters (control arm) did not receive traps. The effect of mass trapping on adult Ae. aegypti abundance was monitored fortnightly with BGS traps. During the last two months of the study, a serological survey was conducted. After the study, a second questionnaire was applied in the intervention arm. Entomological monitoring indicated that MQT mass trapping did not reduce adult Ae. aegypti abundance. The serological survey indicated that recent dengue infections were equally frequent in the intervention and the control arm. Most participants responded positively to questions concerning user satisfaction. According to the results, there is no evidence that mass trapping with MQTs can be used as a part of dengue control programs. The use of this sticky trap is only recommendable for dengue vector monitoring. PMID:25946154

  3. The habitats exploited and the species trapped in a Caribbean island trap fishery

    USGS Publications Warehouse

    Garrison, V.H.; Rogers, C.S.; Beets, J.; Friedlander, A.M.

    2004-01-01

    We visually observed fish traps in situ to identify the habitats exploited by the U.S. Virgin Islands fishery and to document species composition and abundance in traps by habitat. Fishers set more traps in algal plains than in any other habitat around St. John. Coral reefs, traditionally targeted by fishers, accounted for only 16% of traps. Traps in algal plain contained the highest number of fishes per trap and the greatest numbers of preferred food species. Traps on coral reefs contained the most species, 41 of the 59 taxa observed in the study. Acanthurus coeruleus was the most abundant species and Acanthuridae the most abundant family observed in traps. Piscivore numbers were low and few serranids were observed. Traps in algal plain contained the most fishes as a result of: ecological changes such as shifts in habitat use, mobility of species and degradation of nearshore habitat (fishery independent); and, catchability of fishes and long-term heavy fishing pressure (fishery dependent). The low number of serranids per trap, dominance of the piscivore guild by a small benthic predator, Epinephelus guttatus, and dominance of trap contents overall by a small, fast-growing species of a lower trophic guild, Acanthurus coeruleus, all point to years of intense fishing pressure.

  4. A sensitive detection method for high resolution spectroscopy of trapped antihydrogen, hydrogen and other trapped species

    NASA Astrophysics Data System (ADS)

    Lenz Cesar, Claudio

    2016-04-01

    A method for detection of the weak 1s-2s laser excitation of a few trapped antihydrogen atoms is described. It involves the typical antihydrogen trapping environment that combines a magnetic trap for the atoms as well as a Penning trap for its constituent particles. By photoionization of the excited state the photoion can be kept in a weak Penning trap and at a suitable time be ejected towards a charged particle detector such as a microchannel plate or a channel electron multiplier. Since it does not rely on annihilation, the method is also suitable for trapped hydrogen and may find application with other species when a weak transition to a metastable state is intended and only a few trapped atoms or molecules are available.

  5. Flow past tandem cylinders under forced vibration

    NASA Astrophysics Data System (ADS)

    Yang, Yingchen; Aydin, Tayfun B.; Ekmekci, Alis

    2014-01-01

    Flow past two cylinders in tandem arrangement under forced vibration has been studied experimentally employing the hydrogen bubble visualization technique. The Reynolds number, based on the cylinder diameter, is fixed at Re=250. In stationary state of the two cylinders with P/D=2.0, dual vortex shedding frequencies fL (St=0.14) and fH (St=0.18) are identified. fL is associated with the shear layer reattachment behavior and fH is related to the single bluff body behavior. Under a variety of forced vibrations of the two cylinders at a fixed vibration amplitude A/D=0.25, diverse and highly-repetitive vortex patterns are yielded. They are classified into two typical modes—a low-frequency mode and a high-frequency mode. The two modes are represented by two vortex patterns yielded from in-phase vibration of the two cylinders with P/D=2.0 and at vibration frequencies fe≈fL and fe≈fH. The difference between the two modes is on the number of vortices formed per vibration cycle. For the low-frequency mode, the number is four; for the high-frequency model, it is two. In both modes, the vortex formation is phase-locked to the cylinder motion. For a specified mode with a fixed vortex number per cycle, the way the vortices evolve in the wake can be somewhat different by changing the vibration frequency, pitch ratio, as well as the vibration type. These affecting factors have been examined in this work, and the associated vortex patterns have been characterized and compared.

  6. Optimal shortcuts for atomic transport in anharmonic traps

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Muga, J. G.; Guéry-Odelin, D.; Chen, Xi

    2016-06-01

    We design fast trap trajectories to transport cold atoms in anharmonic traps, combining invariant-based inverse engineering, perturbation theory, and optimal control theory. Among the ideal trajectories for harmonic traps, we choose the ones that minimize the anharmonic energy.

  7. Ultrafast entanglement of trapped ions

    NASA Astrophysics Data System (ADS)

    Neyenhuis, Brian; Johnson, Kale; Mizrahi, Jonathan; Wong-Campos, David; Monroe, Christopher

    2014-05-01

    We have demonstrated ultrafast spin-motion entanglement of a single atomic ion using a short train of intense laser pulses. This pulse train gives the ion a spin-dependent kick where each spin state receives a discrete momentum kick in opposite directions. Using a series of these spin-dependent kicks we can realize a two qubit gate. In contrast to gates using spectroscopically resolved motional sidebands, these gates may be performed faster than the trap oscillation period, making them potentially less sensitive to noise. Additionally this gate is temperature insensitive and does not require the ions to be cooled to the Lamb-Dicke limit. We show that multiple kicks can be strung together to create a ``Schrodinger cat'' like state, where the large separation between the two parts of the wavepacket allow us to accumulate the phase shift necessary for a gate in a shorter amount of time. We will present a realistic pulse scheme for a two ion gate, and our progress towards its realization. This work is supported by grants from the U.S. Army Research Office with funding from the DARPA OLE program, IARPA, and the MURI program; and the NSF Physics Frontier Center at JQI.

  8. Collisionless Trapped Electron Mode Turbulence

    NASA Astrophysics Data System (ADS)

    Lang, Jianying; Chen, Yang; Parker, Scott

    2006-10-01

    Collisionless Trapped Electron Mode (CTEM) turbulence is a likely canidate for explaining anomolous transport in tokamak discharges that have a strong density gradient relative to the ion temperature gradient. Here, CTEM turbulence is investigated using the Gyrokinetic δf GEM code. GEM is electromagnetic, includes full drift-kinetic electrons, generaly axisymmetric equilbria, collisions and minority species. Here, the flux-tube limit is taken and β is so small that the simulations are essentially electrostatic. Linear theory predicts that the instability occurs at √2ɛRLn>1, which agrees very well with the simulation results. With increasing density gradient, it is observed that the most unstable mode transitions from a CTEM to drift wave mode and the short-wavelength modes are most unstable ( 2 > kρi> 1). Nonlinear simulations are underway to address the parametric dependence of particle and energy transport. The importance of zonal flows for CTEM turbulence, is still not well understood and is under investigation. D. R. Ernst et. al., Phys. Plasma 11 (2004) 2637 T. Dannert and F. Jenko, Phys. Plasma 12 (2005) 072309 R. Gatto et. al., Phys. Plasma 13 (2006) 022306 Y. Chen and S. E. Parker, J. Comput. Phys. 189 (2003) 463 Y. Chen ad S.E. Parker, accepted, to appear in J. Comput. Phys. (2006) J. Wesson (1997) Tokamaks, Oxford Science

  9. Nonlinear spectroscopy of trapped ions

    NASA Astrophysics Data System (ADS)

    Schlawin, Frank; Gessner, Manuel; Mukamel, Shaul; Buchleitner, Andreas

    2014-08-01

    Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and it has become a highly successful method for experiments in chemical physics. Current quantum optical experiments approach system sizes and levels of complexity that require the development of efficient techniques to assess spectral and dynamical features with scalable experimental overhead. However, established methods from optical spectroscopy of macroscopic ensembles cannot be applied straightforwardly to few-atom systems. Based on the ideas proposed in M. Gessner et al., (arXiv:1312.3365), we develop a diagrammatic approach to construct nonlinear measurement protocols for controlled quantum systems, and we discuss experimental implementations with trapped ion technology in detail. These methods, in combination with distinct features of ultracold-matter systems, allow us to monitor and analyze excitation dynamics in both the electronic and vibrational degrees of freedom. They are independent of system size, and they can therefore reliably probe systems in which, e.g., quantum state tomography becomes prohibitively expensive. We propose signals that can probe steady-state currents, detect the influence of anharmonicities on phonon transport, and identify signatures of chaotic dynamics near a quantum phase transition in an Ising-type spin chain.

  10. Managing resonant trapped orbits in our Galaxy

    NASA Astrophysics Data System (ADS)

    Binney, James

    2016-08-01

    Galaxy modelling is greatly simplified by assuming the existence of a global system of angle-action coordinates. Unfortunately, global angle-action coordinates do not exist because some orbits become trapped by resonances, especially where the radial and vertical frequencies coincide. We show that in a realistic Galactic potential such trapping occurs only on thick-disc and halo orbits (speed relative to the guiding centre ≳ 80 km s-1). We explain how the Torus Mapper code (TM) behaves in regions of phase space in which orbits are resonantly trapped, and we extend TM so trapped orbits can be manipulated as easily as untrapped ones. The impact that the resonance has on the structure of velocity space depends on the weights assigned to trapped orbits. The impact is everywhere small if each trapped orbit is assigned the phase space density equal to the time average along the orbit of the DF for untrapped orbits. The impact could be significant with a different assignment of weights to trapped orbits.

  11. Fluorescent prey traps in carnivorous plants.

    PubMed

    Kurup, R; Johnson, A J; Sankar, S; Hussain, A A; Sathish Kumar, C; Sabulal, B

    2013-05-01

    Carnivorous plants acquire most of their nutrients by capturing ants, insects and other arthropods through their leaf-evolved biological traps. So far, the best-known attractants in carnivorous prey traps are nectar, colour and olfactory cues. Here, fresh prey traps of 14 Nepenthes, five Sarracenia, five Drosera, two Pinguicula species/hybrids, Dionaea muscipula and Utricularia stellaris were scanned at UV 366 nm. Fluorescence emissions of major isolates of fresh Nepenthes khasiana pitcher peristomes were recorded at an excitation wavelength of 366 nm. N. khasiana field pitcher peristomes were masked by its slippery zone extract, and prey capture rates were compared with control pitchers. We found the existence of distinct blue fluorescence emissions at the capture spots of Nepenthes, Sarracenia and Dionaea prey traps at UV 366 nm. These alluring blue emissions gradually developed with the growth of the prey traps and diminished towards their death. On excitation at 366 nm, N. khasiana peristome 3:1 CHCl3–MeOH extract and its two major blue bands showed strong fluorescence emissions at 430–480 nm. Masking of blue emissions on peristomes drastically reduced prey capture in N. khasiana pitchers. We propose these molecular emissions as a critical factor attracting arthropods and other visitors to these carnivorous traps. Drosera, Pinguicula and Utricularia prey traps showed only red chlorophyll emissions at 366 nm. PMID:23696970

  12. Residual CO2 trapping in Indiana limestone.

    PubMed

    El-Maghraby, Rehab M; Blunt, Martin J

    2013-01-01

    We performed core flooding experiments on Indiana limestone using the porous plate method to measure the amount of trapped CO(2) at a temperature of 50 °C and two pressures: 4.2 and 9 MPa. Brine was mixed with CO(2) for equilibration, then the mixture was circulated through a sacrificial core. Porosity and permeability tests conducted before and after 884 h of continuous core flooding confirmed negligible dissolution. A trapping curve for supercritical (sc)CO(2) in Indiana showing the relationship between the initial and residual CO(2) saturations was measured and compared with that of gaseous CO(2). The results were also compared with scCO(2) trapping in Berea sandstone at the same conditions. A scCO(2) residual trapping end point of 23.7% was observed, indicating slightly less trapping of scCO(2) in Indiana carbonates than in Berea sandstone. There is less trapping for gaseous CO(2) (end point of 18.8%). The system appears to be more water-wet under scCO(2) conditions, which is different from the trend observed in Berea; we hypothesize that this is due to the greater concentration of Ca(2+) in brine at higher pressure. Our work indicates that capillary trapping could contribute to the immobilization of CO(2) in carbonate aquifers. PMID:23167314

  13. High-Efficiency Polycrystalline Thin Film Tandem Solar Cells.

    PubMed

    Kranz, Lukas; Abate, Antonio; Feurer, Thomas; Fu, Fan; Avancini, Enrico; Löckinger, Johannes; Reinhard, Patrick; Zakeeruddin, Shaik M; Grätzel, Michael; Buecheler, Stephan; Tiwari, Ayodhya N

    2015-07-16

    A promising way to enhance the efficiency of CIGS solar cells is by combining them with perovskite solar cells in tandem devices. However, so far, such tandem devices had limited efficiency due to challenges in developing NIR-transparent perovskite top cells, which allow photons with energy below the perovskite band gap to be transmitted to the bottom cell. Here, a process for the fabrication of NIR-transparent perovskite solar cells is presented, which enables power conversion efficiencies up to 12.1% combined with an average sub-band gap transmission of 71% for photons with wavelength between 800 and 1000 nm. The combination of a NIR-transparent perovskite top cell with a CIGS bottom cell enabled a tandem device with 19.5% efficiency, which is the highest reported efficiency for a polycrystalline thin film tandem solar cell. Future developments of perovskite/CIGS tandem devices are discussed and prospects for devices with efficiency toward and above 27% are given. PMID:26266847

  14. Parallel Tandems of Dye Sensitized Solar Cells with CNT Collector

    NASA Astrophysics Data System (ADS)

    Velten, Josef; Yuan, Chao-Chen; Zakhidov, Anvar

    2009-03-01

    In this presentation, we demonstrate the fabrication of monolithic parallel tandem dye sensitized solar cells using a semitransparent layer of carbon nanotubes. Each DSC sub-cell has titania photoelectrode with two different dyes: N 719 and N 749, which absorb light in different parts of solar spectrum. This layer of carbon nanotubes laminated on highly porous polymeric Millipore filter acts as both the collector of charge carrier and as the catalyst of the I/I3^- redox reaction that completes the function of the cell, overall allowing easier fabrication for tandem solar cell devices, with a potential for creating flexible devices in the future. The parallel tandem shows the total photocurrent which is nearly the sum of two Isc currents of constituent cells, and total Voc, which is average of two Voc, while conventional in-series DSC tandems show the lowest Voc and slightly increased Isc[1]. Thus the higher efficiency can be achieved in parallel DSC tandems, and we discuss the physical reasons for this effect. [1] Yanagida, et.al. J. of Photochemistry and Photobiology A: Chemistry Volume 164, Issues 1-3, 1 June 2004, Pages 33-39

  15. Cooperative cell motility during tandem locomotion of amoeboid cells

    PubMed Central

    Bastounis, Effie; Álvarez-González, Begoña; del Álamo, Juan C.; Lasheras, Juan C.; Firtel, Richard A.

    2016-01-01

    Streams of migratory cells are initiated by the formation of tandem pairs of cells connected head to tail to which other cells subsequently adhere. The mechanisms regulating the transition from single to streaming cell migration remain elusive, although several molecules have been suggested to be involved. In this work, we investigate the mechanics of the locomotion of Dictyostelium tandem pairs by analyzing the spatiotemporal evolution of their traction adhesions (TAs). We find that in migrating wild-type tandem pairs, each cell exerts traction forces on stationary sites (∼80% of the time), and the trailing cell reuses the location of the TAs of the leading cell. Both leading and trailing cells form contractile dipoles and synchronize the formation of new frontal TAs with ∼54-s time delay. Cells not expressing the lectin discoidin I or moving on discoidin I–coated substrata form fewer tandems, but the trailing cell still reuses the locations of the TAs of the leading cell, suggesting that discoidin I is not responsible for a possible chemically driven synchronization process. The migration dynamics of the tandems indicate that their TAs’ reuse results from the mechanical synchronization of the leading and trailing cells’ protrusions and retractions (motility cycles) aided by the cell–cell adhesions. PMID:26912787

  16. Design of a new tandem wings hybrid airship

    NASA Astrophysics Data System (ADS)

    Li, Feng; Ye, ZhengYin; Gao, Chao

    2012-10-01

    It is scientifically important science value and engineering promising to develop the buoyancy-lift integrated hybrid airship for high attitude platform. Through the numerical method, a new tandem wings hybrid airship with both higher utility value and economy efficiency was obtained and its total performance and technical parameters were analyzed in detail. In order to further improve the lift-drag characteristics, we implemented the optimization design for aerodynamic configuration of tandem wings hybrid airship via the response surface method. The results indicate that the tandem wings hybrid airship has considerable volume efficiency and higher aerodynamic characteristics. After optimization, the lift-drag ratio of this hybrid airship was increased by 6.08%. In a given gross lift condition, tandem wings hybrid airship may provide more payload and specific productivity. Furthermore, the size of tandem airship is smaller so the demand for skin flexible materials can be reduced. Results of this study could serve as a new approach to designing buoyancy-lifting integrated hybrid airship.

  17. Test of the Tandem transmission at low terminal voltages

    SciTech Connect

    Rehm, K.E.; Blumenthal, D.; Gehring, J.

    1995-08-01

    For a planned experiment with {sup 18}F beams at energies below 1 MeV/u the transmission of the Tandem-Linac system was investigated. The energies required in the experiment are typically around 600 keV/u, which for the most abundant charge states for F(4{sup +}) corresponds to terminal voltages between 2-3 MV. We studied the transmission from the source to the tandem accelerator and to the spectrograph in area II with {sup 18}O and {sup 19}F beams using two different approaches. In the first method only the tandem accelerator was used producing a 14-MeV DC {sup 18}O beam. In the second method a pulsed beam was accelerated to 33 MeV with the tandem accelerator followed by deceleration to 14 MeV with the first 9 resonators of ATLAS. The total transmission from ion source to target was in both cases about 10%. Because of the smaller complexity we used the first method for the {sup 18}F experiment. In future runs we are planning to use the electrostatic lens in the terminal of the tandem to improve the overall transmission.

  18. The Tandem-ALPI-PIAVE accelerator complex of LNL

    SciTech Connect

    Ur, C. A.

    2013-07-18

    Heavy ion beams are delivered at the Laboratori Nazionali di Legnaro by the accelerator complex Tandem-ALPI-PIAVE. The Tandem XTU is a Van de Graaff accelerator normally operated at terminal voltages of up to about 15 MV. The Tandem accelerator can be operated in stand-alone mode or as an injector for the linac booster ALPI. The linear accelerator ALPI is built of superconducting resonant cavities and consists of a low-beta branch, particularly important for the acceleration of the heavier mass ions, a medium-beta branch, and a high-beta branch. ALPI can be operated also with the PIAVE injector that consists of a superconducting linac and an ECR source. The PIAVE source was mainly used for the acceleration of intense noble gas beams but most recently also a first metallic beam was delivered to the users. The accelerator complex delivers beams of ions from protons to gold in three experimental areas on 11 different beam lines. A rich scientific activity is ongoing at the Tandem-ALPI-PIAVE accelerator complex, beam time being shared between nuclear physics research and applied and interdisciplinary physics research. An overview of the present status and perspectives of the Tandem-ALPI-PIAVE complex and its physics program is given in the present paper.

  19. A method for trapping breeding adult American Oystercatchers

    USGS Publications Warehouse

    McGowan, C.P.; Simons, T.R.

    2005-01-01

    We present an efficient and effective method for trapping adult, breeding American Oystercatchers (Haematopus palliatus) that minimizes disturbance to nesting birds and the risk of trapping injuries. We used a remote controlled mechanical decoy to lure territorial adults to a leg-hold noose-mat trap. We trapped 25 birds over two seasons and were successful on 54% of our trapping attempts in 2003. We only trapped birds before the breeding season or between nesting attempts to reduce nest-site disturbance.

  20. Imaging MS Methodology for More Chemical Information in Less Data Acquisition Time Utilizing a Hybrid Linear Ion Trap-Orbitrap Mass Spectrometer

    SciTech Connect

    Perdian, D. C.; Lee, Young Jin

    2010-11-15

    A novel mass spectrometric imaging method is developed to reduce the data acquisition time and provide rich chemical information using a hybrid linear ion trap-orbitrap mass spectrometer. In this method, the linear ion trap and orbitrap are used in tandem to reduce the acquisition time by incorporating multiple linear ion trap scans during an orbitrap scan utilizing a spiral raster step plate movement. The data acquisition time was decreased by 43-49% in the current experiment compared to that of orbitrap-only scans; however, 75% or more time could be saved for higher mass resolution and with a higher repetition rate laser. Using this approach, a high spatial resolution of 10 {micro}m was maintained at ion trap imaging, while orbitrap spectra were acquired at a lower spatial resolution, 20-40 {micro}m, all with far less data acquisition time. Furthermore, various MS imaging methods were developed by interspersing MS/MS and MSn ion trap scans during orbitrap scans to provide more analytical information on the sample. This method was applied to differentiate and localize structural isomers of several flavonol glycosides from an Arabidopsis flower petal in which MS/MS, MSn, ion trap, and orbitrap images were all acquired in a single data acquisition.

  1. Targeted Tandem Mass Spectrometry for High-Throughput Comparative Proteomics Employing NanoLC-FTICR MS with External Ion Dissociation

    SciTech Connect

    Kang, Hyuk; Pasa-Tolic, Liljiana; Smith, Richard D.

    2007-05-03

    ABSTRACT-Targeted tandem mass spectrometry (MS/MS) is an attractive proteomic approach that allows selective identification of peptides exhibiting abundance differences between culture conditions and/or diseased states. Herein, we report on a targeted LC-MS/MS capability realized with a 7 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer equipped with a quadrupole interface that provides data-dependent ion selection, accumulation, and dissociation externally to the ICR trap. Identification of a subset of differentially abundant proteins from Shewanella oneidensis grown under suboxic vs. aerobic conditions demonstrates the feasibility of such approach. High mass resolution offered by FTICR and effective on-the-fly elution time correction facilitated accurate selection of targets, while high mass measurement accuracy MS/MS data resulted in unambiguous peptide identifications.

  2. Trapping Rydberg Atoms in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Anderson, Sarah E.

    2012-06-01

    Optical lattice traps for Rydberg atoms are of interest in advanced science and in practical applications. After a brief discussion of these areas of interest, I will review some basics of optical Rydberg-atom trapping. The trapping potential experienced by a Rydberg atom in an optical lattice is given by the spatial average of the free-electron ponderomotive energy weighted by the Rydberg electron's probability distribution. I will then present experimental results on the trapping of ^85Rb Rydberg atoms in a one-dimensional ponderomotive optical lattice (wavelength 1064 nm). The principal methods employed to study the lattice performance are microwave spectroscopy, which is used to measure the lattice's trapping efficiency, and photo-ionization, which is used to measure the dwell time of the atoms in the lattice. I have achieved a 90% trapping efficiency for ^85Rb 50S atoms by inverting the lattice immediately after laser excitation of ground-state atoms into Rydberg states. I have characterized the dwell time of the atoms in the lattice using photo-ionization of 50D5/2 atoms. In continued work, I have explored the dependence of the Rydberg-atom trapping potential on the angular portion of the atomic wavefunction. Distinct angular states exhibit different trapping behavior in the optical lattice, depending on how their wavefunctions are oriented relative to the lattice planes. Specifically, I have measured the lattice potential depth of sublevels of ^85Rb nD atoms (50<=n<=65) in a one-dimensional optical lattice with a transverse DC electric field. The trapping behavior varies substantially for the various angular sublevels, in agreement with theory. The talk will conclude with an outlook into planned experiments.

  3. Laser trapping of {sup 21}Na atoms

    SciTech Connect

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  4. Atom trap loss, elastic collisions, and technology

    NASA Astrophysics Data System (ADS)

    Booth, James

    2012-10-01

    The study of collisions and scattering has been one of the most productive approaches for modern physics, illuminating the fundamental structure of crystals, surfaces, atoms, and sub-atomic particles. In the field of cold atoms, this is no less true: studies of cold atom collisions were essential to the production of quantum degenerate matter, the formation of cold molecules, and so on. Over the past few years it has been my delight to investigate elastic collisions between cold atoms trapped in either a magneto-optical trap (MOT) or a magnetic trap with hot, background gas in the vacuum environment through the measurement of the loss of atoms from the trap. Motivated by the goal of creating cold atom-based technology, we are deciphering what the trapped atoms are communicating about their environment through the observed loss rate. These measurements have the advantages of being straightforward to implement and they provide information about the underlying, fundamental inter-atomic processes. In this talk I will present some of our recent work, including the observation of the trap depth dependence on loss rate for argon-rubidium collisions. The data follow the computed loss rate curve based on the long-range Van der Waals interaction between the two species. The implications of these findings are exciting: trap depths can be determined from the trap loss measurement under controlled background density conditions; observation of trap loss rate in comparison to models for elastic, inelastic, and chemical processes can lead to improved understanding and characterization of these fundamental interactions; finally the marriage of cold atoms with collision modeling offers the promise of creating a novel pressure sensor and pressure standard for the high and ultra-high vacuum regime.

  5. Modeling of trap-assisted tunneling on performance of charge trapping memory with consideration of trap position and energy level

    NASA Astrophysics Data System (ADS)

    Lun, Zhi-Yuan; Li, Yun; Zhao, Kai; Du, Gang; Liu, Xiao-Yan; Wang, Yi

    2016-08-01

    In this work, the trap-assisted tunneling (TAT) mechanism is modeled as a two-step physical process for charge trapping memory (CTM). The influence of the TAT mechanism on CTM performance is investigated in consideration of various trap positions and energy levels. For the simulated CTM structure, simulation results indicate that the positions of oxide traps related to the maximum TAT current contribution shift towards the substrate interface and charge storage layer interface during time evolutions in programming and retention operations, respectively. Lower programming voltage and retention operations under higher temperature are found to be more sensitive to tunneling oxide degradation. Project supported by the National Natural Science Foundation of China (Grant Nos. 61404005, 61421005, and 91434201).

  6. Doughnut shape atom traps with arbitrary inclination

    NASA Astrophysics Data System (ADS)

    Masegosa, R. R. Y.; Moya-Cessa, H.; Chavez-Cerda, S.

    2006-02-01

    Since the invention of magneto-optical trap (MOT), there have been several experimental and theoretical studies of the density distribution in these devices. To the best of our knowledge, only horizontal orbital traps have been observed, perpendicular to the coil axis. In this work we report the observation of distributions of trapped atoms in pure circular orbits without a nucleus whose orbital plane is tilted up to 90 degrees with respect to the horizontal plane. We have used a stabilized time phase optical array in our experiments and conventional equipment used for MOT.

  7. Evaporative cooling at low trap depth

    SciTech Connect

    Carvalho, Robert de; Doyle, John

    2004-11-01

    A quantitative, analytic model of evaporative cooling covering both the small- (<4) and large- (>4) {eta} regimes is presented. {eta} is the dimensionless parameter defined as the trap depth divided by the temperature of the trapped sample. Although some of the same general properties present at large {eta} are also present at small {eta}, there are significant quantitative differences. These differences must be taken into account in order to accurately extract from the trapping data quantitative measurements of, for example, collisional atomic cross sections.

  8. Production and Trapping of Ultracold Polar Molecules

    SciTech Connect

    David, DeMille

    2015-04-21

    We report a set of experiments aimed at the production and trapping of ultracold polar molecules. We begin with samples of laser-cooled and trapped Rb and Cs atoms, and bind them together to form polar RbCs molecules. The binding is accomplished via photoassociation, which uses a laser to catalyze the sticking process. We report results from investigation of a new pathway for photoassociation that can produce molecules in their absolute ground state of vibrational and rotational motion. We also report preliminary observations of collisions between these ground-state molecules and co-trapped atoms.

  9. Quantum teleportation with atoms trapped in cavities

    SciTech Connect

    Cho, Jaeyoon; Lee, Hai-Woong

    2004-09-01

    We propose a scheme to implement the quantum teleportation protocol with single atoms trapped in cavities. The scheme is based on the adiabatic passage and the polarization measurement. We show that it is possible to teleport the internal state of an atom trapped in a cavity to an atom trapped in another cavity with the success probability of 1/2 and the fidelity of 1. The scheme is resistant to a number of considerable imperfections such as the violation of the Lamb-Dicke condition, weak atom-cavity coupling, spontaneous emission, and detection inefficiency.

  10. Passive Baited Sequential Filth Fly Trap.

    PubMed

    Aldridge, Robert L; Britch, Seth C; Snelling, Melissa; Gutierez, Arturo; White, Gregory; Linthicum, Kenneth J

    2015-09-01

    Filth fly control measures may be optimized with a better understanding of fly population dynamics measured throughout the day. We describe the modification of a commercial motorized sequential mosquito trap to accept liquid odorous bait and leverage a classic inverted-cone design to passively confine flies in 8 modified collection bottles corresponding to 8 intervals. Efficacy trials in a hot-arid desert environment indicate no significant difference (P  =  0.896) between the modified sequential trap and a Rid-Max® fly trap. PMID:26375911

  11. Trapped antihydrogen in its ground state.

    PubMed

    Gabrielse, G; Kalra, R; Kolthammer, W S; McConnell, R; Richerme, P; Grzonka, D; Oelert, W; Sefzick, T; Zielinski, M; Fitzakerley, D W; George, M C; Hessels, E A; Storry, C H; Weel, M; Müllers, A; Walz, J

    2012-03-16

    Antihydrogen atoms (H¯) are confined in an Ioffe trap for 15-1000 s-long enough to ensure that they reach their ground state. Though reproducibility challenges remain in making large numbers of cold antiprotons (p¯) and positrons (e(+)) interact, 5±1 simultaneously confined ground-state atoms are produced and observed on average, substantially more than previously reported. Increases in the number of simultaneously trapped H¯ are critical if laser cooling of trapped H¯ is to be demonstrated and spectroscopic studies at interesting levels of precision are to be carried out. PMID:22540471

  12. Hydrophilic interaction liquid chromatography-electrospray ionization-tandem mass spectrometry of a complex mixture of native and oxidized phospholipids.

    PubMed

    Losito, I; Facchini, L; Diomede, S; Conte, E; Megli, F M; Cataldi, T R I; Palmisano, F

    2015-11-27

    A mixture of native and oxidized phospholipids (PLs), generated by the soybean lipoxygenase type V-catalyzed partial oxidation of a lipid extract obtained from human platelets, was analyzed by Hydrophilic Interaction Liquid Chromatography-ElectroSpray Ionization-Tandem Mass Spectrometry (HILIC-ESI-MS/MS). The complexity of the resulting mixture was remarkable, considering that the starting lipid extract, containing (as demonstrated in a previous study) about 130 native PLs, was enriched with enzymatically generated hydroperoxylated derivatives and chemically generated hydroxylated forms of PLs bearing polyunsaturated side chains. Nonetheless, the described analytical approach proved to be very powerful; indeed, focusing on phosphatidylcolines (PCs), the most abundant PL class in human platelets, about fifty different native/oxidized species could be identified in a single HILIC-ESI-MS/MS run. Low-energy collision induced dissociation tandem MS (CID-MS/MS) experiments on chromatographically separated species showed single neutral losses of H2O2 and H2O to be typical fragmentation pathways of hydroperoxylated PCs, whereas a single H2O loss was observed for hydroxylated ones. Moreover, diagnostic losses of n-hexanal or n-pentanol were exploited to recognize PCs hydroperoxylated on the last but five carbon atom of a ɷ-6 polyunsaturated side chain. Despite the low resolution of the 3D ion trap mass analyzer used, the described HILIC-ESI-MS/MS approach appears very promising for the identification of oxidized lipids in oxidatively stressed complex biological systems. PMID:26508677

  13. Simultaneous quantitation and identification of organic and inorganic selenium in diet supplements by liquid chromatography with tandem mass spectrometry.

    PubMed

    Zembrzuska, Joanna; Matusiewicz, Henryk; Polkowska-Motrenko, Halina; Chajduk, Ewelina

    2014-01-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for selenium speciation in dietary supplements. Chromatographic separation was performed on a TSK-Gel ODS-100V column using a mixture of 5mM ammonium acetate water solution and methanol as a mobile phase. Conditions chosen for this process allowed to separate all investigated chemical compounds of selenium: seleno-l-methionine, methyl-seleno-l-cysteine, l-selenocystine, methaneseleninic acid, selenite and selenate. A tandem mass spectrometer with an ion trap operating in negative or positive ion mode according to the selenium form being determined was used as a detector. Three extraction procedures: water extraction, enzymatic hydrolysis and sequential extraction were used for preparation of samples for the determination of the actual forms of selenium in diet supplements. The developed method was used for analysis of six dietary supplements containing selenium bought in a pharmacy and supermarket. Apart from speciation analysis of selenium content in supplements total selenium content was determined using instrumental neutron activation analysis (INAA). All expected forms of selenium except for selenite were determined using LC-MS/MS technique. It should be stressed that amounts of selenate were smaller than expected. PMID:24001829

  14. Evidence for covalent binding of acyl glucuronides to serum albumin via an imine mechanism as revealed by tandem mass spectrometry.

    PubMed Central

    Ding, A; Ojingwa, J C; McDonagh, A F; Burlingame, A L; Benet, L Z

    1993-01-01

    Acyl glucuronide metabolites of bilirubin and many drugs can react with serum albumin in vivo to form covalent adducts. Such adducts may be responsible for some toxic effects of carboxylic nonsteroidal antiinflammatory agents. The mechanism of formation of the adducts and their chemical structures are unknown. In this paper we describe the use of tandem mass spectrometry to locate binding sites and elucidate the binding mechanism involved in the formation of covalent adducts from tolmetin glucuronide and albumin in vitro. Human serum albumin and excess tolmetin glucuronide were coincubated in the presence of sodium cyanoborohydride to trap imine intermediates. The total protein product was reduced, carboxymethylated, and digested with trypsin. Six tolmetin-containing peptides (indicated by absorbance at 313 nm) were isolated by high-pressure liquid chromatography and analyzed by liquid secondary-ion mass spectrometry and collision-induced dissociation, using a four-sector tandem mass spectrometer. All six peptides contained tolmetin linked covalently via a glucuronic acid to protein lysine groups. Major attachment sites on the protein were Lys-195, -199, and -525; minor sites were identified as Lys-137, -351, and -541. Our results show unambiguously that the glucuronic acid moiety of acyl glucuronides can be retained within the structure when these reactive metabolites bind covalently to proteins, and they suggest that acyl migration followed by Schiff base (imine) formation is a credible mechanism for the generation of covalent adducts in vivo. PMID:8483897

  15. Chemical and physical properties of ultrafine diesel exhaust particles sampled downstream of a catalytic trap.

    PubMed

    Grose, Melissa; Sakurai, Hiromu; Savstrom, Jake; Stolzenburg, Mark R; Watts, Winthrop F; Morgan, Christopher G; Murray, Ian P; Twigg, Martyn V; Kittelson, David B; McMurry, Peter H

    2006-09-01

    The chemical and physical properties of exhaust particles produced by a Caterpillar 3176 C-12 heavy duty diesel engine equipped with a catalytic trap (CRT) are reported. The engine was operated at 600 Nm and 1500 rpm, using fuels containing 15 and 49 ppm sulfur. A two-stage dilution tunnel designed to simulate the reactions that occur when hot combustion products mix with cooler atmospheric air was used. Particle size distributions were measured using a scanning mobility particle sizer (SMPS) and nano-scanning mobility particle sizer (nano SMPS); a nanomicro-orifice uniform deposit impactor (nano MOUDI) collected size-resolved samples for gravimetric and chemical analysis. A nanometer tandem differential mobility analyzer (nano TDMA) was used to measure the volatility and hygroscopicity of 4-15 nm particles. These measurements confirm that the particles consisted primarily of sulfates. PMID:16999131

  16. Dosimetric Comparison of Tandem and Ovoids vs. Tandem and Ring for Intracavitary Gynecologic Applications

    SciTech Connect

    Levin, Daphne Menhel, Janna; Rabin, Tanya; Pfeffer, M. Raphael; Symon, Zvi

    2008-01-01

    We evaluated dosimetric differences in tandem and ovoid (TO) and tandem and ring (TR) gynecologic brachytherapy applicators. Seventeen patients with cervical cancer (Stages II-IV) receiving 3 high-dose-rate (HDR) brachytherapy applications (both TO and TR) were studied. Patients underwent computed tomography (CT) scans with contrast in bladder, and were prescribed 8 Gy to ICRU points A, with additional optimization goals of maintaining the pear-shaped dose distribution and minimizing bladder and rectum doses. Bladder and rectum point doses, mean, and maximum doses were calculated. Total treatment time and volumes treated to 95%, 85%, 50%, and 20% or the prescription dose were compared. There were no significant differences between TO and TR applicators in doses to prescription points or critical organs. However, there were significant differences (p < 0.001) between the applicators in treated volumes and total treatment time. The TO treated larger volumes over a longer time. Within each patient, when the applicators were compared, treated volumes were also found to be significantly different (p < 0.01, {chi}{sup 2}). Our results demonstrate that the 2 applicators, while delivering the prescribed dose to points A and keeping critical organ doses below tolerance, treat significantly different volumes. It is unclear if this difference is clinically meaningful. TO applicators may be treating surrounding healthy tissue unnecessarily, or TR applicators may be underdosing tumor tissue. Further investigation with appropriate imaging modalities is required for accurate delineation of target volumes. Clearly, the TO and TR are not identical, and should not be used interchangeably without further study.

  17. Counter-Rotating Tandem Motor Drilling System

    SciTech Connect

    Kent Perry

    2009-04-30

    Gas Technology Institute (GTI), in partnership with Dennis Tool Company (DTC), has worked to develop an advanced drill bit system to be used with microhole drilling assemblies. One of the main objectives of this project was to utilize new and existing coiled tubing and slimhole drilling technologies to develop Microhole Technology (MHT) so as to make significant reductions in the cost of E&P down to 5000 feet in wellbores as small as 3.5 inches in diameter. This new technology was developed to work toward the DOE's goal of enabling domestic shallow oil and gas wells to be drilled inexpensively compared to wells drilled utilizing conventional drilling practices. Overall drilling costs can be lowered by drilling a well as quickly as possible. For this reason, a high drilling rate of penetration is always desired. In general, high drilling rates of penetration (ROP) can be achieved by increasing the weight on bit and increasing the rotary speed of the bit. As the weight on bit is increased, the cutting inserts penetrate deeper into the rock, resulting in a deeper depth of cut. As the depth of cut increases, the amount of torque required to turn the bit also increases. The Counter-Rotating Tandem Motor Drilling System (CRTMDS) was planned to achieve high rate of penetration (ROP) resulting in the reduction of the drilling cost. The system includes two counter-rotating cutter systems to reduce or eliminate the reactive torque the drillpipe or coiled tubing must resist. This would allow the application of maximum weight-on-bit and rotational velocities that a coiled tubing drilling unit is capable of delivering. Several variations of the CRTDMS were designed, manufactured and tested. The original tests failed leading to design modifications. Two versions of the modified system were tested and showed that the concept is both positive and practical; however, the tests showed that for the system to be robust and durable, borehole diameter should be substantially larger than

  18. Advancing tandem solar cells by spectrally selective multilayer intermediate reflectors.

    PubMed

    Hoffmann, Andre; Paetzold, Ulrich W; Zhang, Chao; Merdzhanova, Tsvetelina; Lambertz, Andreas; Ulbrich, Carolin; Bittkau, Karsten; Rau, Uwe

    2014-08-25

    Thin-film silicon tandem solar cells are composed of an amorphous silicon top cell and a microcrystalline silicon bottom cell, stacked and connected in series. In order to match the photocurrents of the top cell and the bottom cell, a proper photon management is required. Up to date, single-layer intermediate reflectors of limited spectral selectivity are applied to match the photocurrents of the top and the bottom cell. In this paper, we design and prototype multilayer intermediate reflectors based on aluminum doped zinc oxide and doped microcrystalline silicon oxide with a spectrally selective reflectance allowing for improved current matching and an overall increase of the charge carrier generation. The intermediate reflectors are successfully integrated into state-of-the-art tandem solar cells resulting in an increase of overall short-circuit current density by 0.7 mA/cm(2) in comparison to a tandem solar cell with the standard single-layer intermediate reflector. PMID:25322181

  19. High efficiency all-polymer tandem solar cells

    NASA Astrophysics Data System (ADS)

    Yuan, Jianyu; Gu, Jinan; Shi, Guozheng; Sun, Jianxia; Wang, Hai-Qiao; Ma, Wanli

    2016-05-01

    In this work, we have reported for the first time an efficient all-polymer tandem cell using identical sub-cells based on P2F-DO:N2200. A high power conversion efficiency (PCE) of 6.70% was achieved, which is among the highest efficiencies for all polymer solar cells and 43% larger than the PCE of single junction cell. The largely improved device performance can be mainly attributed to the enhanced absorption of tandem cell. Meanwhile, the carrier collection in device remains efficient by optimizing the recombination layer and sub-cell film thickness. Thus tandem structure can become an easy approach to effectively boost the performance of current all polymer solar cells.

  20. Enantioselective tandem reaction over a site-isolated bifunctional catalyst.

    PubMed

    Xu, Jianyou; Cheng, Tanyu; Zhang, Kun; Wang, Ziyun; Liu, Guohua

    2016-05-21

    Construction of a site-isolated heterogeneous catalyst to realize the compatibility of bimetallic complexes for a feasible tandem reaction is a significant challenge in heterogeneous asymmetric catalysis. Herein, taking advantage of yolk-shell-structured mesoporous silica, we assemble an active site-isolated bifunctional catalyst through assembly of organopalladium-functionality into silicate channels as an outer shell and chiral organoruthenium-functionality onto silicate yolk as an inner core, realizing the one-pot enantioselective tandem reaction from Pd-catalyzed Sonogashira coupling to Ru-catalyzed asymmetric transfer hydrogenation. As presented in this study, this tandem Sonogashira coupling-asymmetric transfer hydrogenation of haloacetophenones and arylacetylenes affords various chiral conjugated alkynols with high yields and up to 99% enantioselectivity. Moreover, a catalyst can also be recovered easily and recycled repeatedly, making it an interesting feature in a practical organic transformation. PMID:27063335

  1. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Loferski, J. J.

    1976-01-01

    Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

  2. Tandem repeat distribution of gene transcripts in three plant families

    PubMed Central

    2009-01-01

    Tandem repeats (microsatellites or SSRs) are molecular markers with great potential for plant genetic studies. Modern strategies include the transfer of these markers among widely studied and orphan species. In silico analyses allow for studying distribution patterns of microsatellites and predicting which motifs would be more amenable to interspecies transfer. Transcribed sequences (Unigene) from ten species of three plant families were surveyed for the occurrence of micro and minisatellites. Transcripts from different species displayed different rates of tandem repeat occurrence, ranging from 1.47% to 11.28%. Both similar and different patterns were found within and among plant families. The results also indicate a lack of association between genome size and tandem repeat fractions in expressed regions. The conservation of motifs among species and its implication on genome evolution and dynamics are discussed. PMID:21637460

  3. High efficiency all-polymer tandem solar cells

    PubMed Central

    Yuan, Jianyu; Gu, Jinan; Shi, Guozheng; Sun, Jianxia; Wang, Hai-Qiao; Ma, Wanli

    2016-01-01

    In this work, we have reported for the first time an efficient all-polymer tandem cell using identical sub-cells based on P2F-DO:N2200. A high power conversion efficiency (PCE) of 6.70% was achieved, which is among the highest efficiencies for all polymer solar cells and 43% larger than the PCE of single junction cell. The largely improved device performance can be mainly attributed to the enhanced absorption of tandem cell. Meanwhile, the carrier collection in device remains efficient by optimizing the recombination layer and sub-cell film thickness. Thus tandem structure can become an easy approach to effectively boost the performance of current all polymer solar cells. PMID:27226354

  4. High efficiency all-polymer tandem solar cells.

    PubMed

    Yuan, Jianyu; Gu, Jinan; Shi, Guozheng; Sun, Jianxia; Wang, Hai-Qiao; Ma, Wanli

    2016-01-01

    In this work, we have reported for the first time an efficient all-polymer tandem cell using identical sub-cells based on P2F-DO:N2200. A high power conversion efficiency (PCE) of 6.70% was achieved, which is among the highest efficiencies for all polymer solar cells and 43% larger than the PCE of single junction cell. The largely improved device performance can be mainly attributed to the enhanced absorption of tandem cell. Meanwhile, the carrier collection in device remains efficient by optimizing the recombination layer and sub-cell film thickness. Thus tandem structure can become an easy approach to effectively boost the performance of current all polymer solar cells. PMID:27226354

  5. A tandem mirror hybrid plume plasma propulsion facility

    NASA Technical Reports Server (NTRS)

    Yang, T. F.; Krueger, W. A.; Peng, S.; Urbahn, J.; Chang-Diaz, F. R.

    1988-01-01

    This paper discusses a novel concept in electrodeless plasma propulsion, in which the materials problems are ameliorated by an electrodeless magnetic confinement scheme borrowed from the tandem mirror approach to controlled thermonuclear fusion. The concept also features a two-stage magnetic nozzle with an annular hypersonic coaxial gas injector near the throat. The nozzle produces hybrid plume by the coaxial injection of hypersonic neutral gas, and the gas layer thus formed protects the material walls from the hot plasma and, through increased collisions, helps detach it from the diverging magnetic field. The tandem mirror plasma propulsion facility is capable of delivering a variable I(sp). The results of numerical simulation of this concept are presented together with those from an experimental tandem-mirror plasma propulsion device.

  6. Highly Loaded Fan by Using Tandem Cascade Rotor Blade

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Suga, Shinya; Matsuoka, Akinori

    For axial flow compressors and fans in the aircraft engines higher pressure ratio is required in order to attain the high thrust engines. In this study, the fan with the tandem cascades was introduced to increase the fan pressure ratio. The use of tandem cascades in the fan allows savings in length and weight and therefore a compact fan could be built. The design of fan with tandem cascades and the fan testing were carried out to develop the high pressure ratio fan for the Air Turbo Ramjet (ATR) propulsion system. The ATR is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds. In particular, high fan pressure ratio contributes to increase the engine thrust during subsonic flight at which the engine does not make use of ram effect. The results of the fan testing indicate that the pressure ratio of 2.2 is achieved in single stage fan.

  7. Snowball Earth and basaltic traps

    NASA Astrophysics Data System (ADS)

    Dupre, B.; Godderis, Y.; Nedelec, A.; Donnadieu, Y.; Dessert, C.; Francois, L. M.; Grard, A.

    2003-04-01

    The causes of the Neo-Proterozoic glaciations is still a matter of debate. One potential trigger for those glaciations is a major perturbation of the global carbon cycle, leading to the consumption of atmospheric CO_2, and finally to the cooling of the global climate. The first glacial episode is characterized by intense rift formations. The Proto-Pacific ocean starts to open within the Sturtian stage (800-750 Ma). The onset of rifts cutting through continental surfaces might have been coeval with the spreading of continental flood basalts. As demonstrated by Dessert et al (2001) for the K-T boundary, such events might severely impacts the long term evolution of the global climate, through intense consumption of atmospheric CO_2 by fresh basaltic surfaces, leading to non negligible global cooling at the million year timescale. Based on weathering laws for basaltic and granitic surfaces, we estimate that the onset of continental flood basalts over 6 million km^2 along the equator (crossed by the Proto-Pacific rift) will drive the Earth into global glaciation 1.5 My after the event, assuming a pre-perturbation level of 280 ppmv of CO_2 and a solar luminosity reduced by 6%. The δ13C of carbonates accumulating between the start of the continental plume and the onset of the global glaciation is expected to fall by about 3 ppm in response to the degassing of large amount of mantle carbon into the atmosphere, in agreement with data. This hypothesis raises the question of the cyclicity of the glaciations. Once the glaciation ends, the basaltic surface starts again to weather, and plunge the Earth into a new deep glaciation. Within 30 My, the basaltic trap, originally located at the equator, might have migrated 3500 km southward, within the dryer tropical area. Such migration reduces the consumption of CO_2 by the basaltic surface, preventing the Earth from a new global glaciation.

  8. Cellular folate vitamer distribution during and after correction of vitamin B12 deficiency: a case for the methylfolate trap.

    PubMed

    Smulders, Y M; Smith, D E C; Kok, R M; Teerlink, T; Swinkels, D W; Stehouwer, C D A; Jakobs, C

    2006-03-01

    Haematological sequellae of vitamin B12 deficiency are attributed to disturbed DNA synthesis, but vitamin B12 itself plays no role in DNA biosynthesis. A proposed explanation for this is the methylfolate trap hypothesis. This hypothesis states that B12 deficiency impairs overall folate metabolism because 5-methyltetrahydrofolate (5MTHF) becomes metabolically trapped. This trap results from the fact that 5MTHF can neither be metabolised via the methionine synthase pathway, nor can it be reconverted to its precursor, methylenetetrahydrofolate. Other manifestations of the methylfolate trap include cellular folate loss because of shorter 5MTHF polyglutamate chains and global hypomethylation. The methylfolate trap has never been demonstrated in humans. We describe a patient with B12 deficiency who was homozygous for the common methylenetetrahydrofolate reductase (MTHFR) C677T mutation. We analysed red blood cell (RBC) folate vitamers and global DNA methylation by liquid chromatography (LC) in combination with tandem mass spectrometry, and 5MTHF polyglutamate length by LC-electrochemical detection. Compared to post-B12 supplementation values, homocysteine was higher (52.9 micromol/l vs. 16.8 micromol/l), RBC folate was lower (268.92 nmol/l vs. 501.2 nmol/l), the 5MTHF fraction of RBC folate was much higher (94.5% vs. 67.4%), polyglutamate chain length was shorter (more tetra- and pentaglutamates), and global DNA methylation was 22% lower. This is the first time that virtually all features of the methylfolate trap hypothesis have been demonstrated in a human with vitamin B12 deficiency. PMID:16445837

  9. Time-of-flights and traps: from the Histone Code to Mars*

    PubMed Central

    Swatkoski, Stephen; Becker, Luann; Evans-Nguyen, Theresa

    2011-01-01

    Two very different analytical instruments are featured in this perspective paper on mass spectrometer design and development. The first instrument, based upon the curved-field reflectron developed in the Johns Hopkins Middle Atlantic Mass Spectrometry Laboratory, is a tandem time-of-flight mass spectrometer whose performance and practicality are illustrated by applications to a series of research projects addressing the acetylation, deacetylation and ADP-ribosylation of histone proteins. The chemical derivatization of lysine-rich, hyperacetylated histones as their deuteroacetylated analogs enables one to obtain an accurate quantitative assessment of the extent of acetylation at each site. Chemical acetylation of histone mixtures is also used to determine the lysine targets of sirtuins, an important class of histone deacetylases (HDACs), by replacing the deacetylated residues with biotin. Histone deacetylation by sirtuins requires the co-factor NAD+, as does the attachment of ADP-ribose. The second instrument, a low voltage and low power ion trap mass spectrometer known as the Mars Organic Mass Analyzer (MOMA), is a prototype for an instrument expected to be launched in 2018. Like the tandem mass spectrometer, it is also expected to have applicability to environmental and biological analyses and, ultimately, to clinical care. PMID:20530839

  10. NASA Provides Assistance to Trapped Chilean Miners

    NASA Video Gallery

    Responding to a request received through the U.S. Department of State from the Chilean minister of health, NASA will provide advice in nutritional and behavioral sciences to assist miners trapped a...

  11. Trapping and sorting active granular rods

    NASA Astrophysics Data System (ADS)

    Ramaswamy, Sriram; Kumar, Nitin; Soni, Harsh; Gupta, Rahul; Sood, Ajay

    We report experiments and simulations on collective trapping in a horizontal monolayer of tapered granular rods rendered motile by mechanical vibration. A macroscopic fraction of the particles are trapped by a V-shaped obstacle if its opening angle is less than a threshold value of about 120 degrees, consistent with active Brownian simulations [PRL 108, 268307 (2012)]. the transition between trapped and untrapped states becomes sharper with increasing system size in our numerical studies. We offer a theoretical understanding of this nonequilibrium phase transition based on collective noise suppression and an analysis of fluxes. We show also that the trap can serve to separate particles based on their motility and rotational diffusivity. On leave from Dept of Physics, Indian Institute of Science.

  12. Three-Rod Linear Ion Traps

    NASA Technical Reports Server (NTRS)

    Janik, Gary R.; Prestage, John D.; Maleki, Lutfollah

    1993-01-01

    Three-parallel-rod electrode structures proposed for use in linear ion traps and possibly for electrostatic levitation of macroscopic particles. Provides wider viewing angle because they confine ions in regions outside rod-electrode structures.

  13. Trapped Ion Optical Clocks at NPL

    SciTech Connect

    Margolis, H. S.; Barwood, G. P.; Hosaka, K.; Klein, H. A.; Lea, S. N.; Walton, B. R.; Webster, S. A.; Gill, P.; Huang, G.; Stannard, A.

    2006-11-07

    Forbidden transitions in single laser-cooled trapped ions provide highly stable and accurate references for optical frequency standards. This paper describes recent progress on strontium and ytterbium ion optical frequency standards under development at NPL.

  14. Blowfly Succession--A Simple Trap.

    ERIC Educational Resources Information Center

    Brown, Kenneth R.

    1991-01-01

    A portable and inexpensive blowfly trap, constructed from flower pots/buckets and mesh, suitable for introductory studies in blowfly succession is described. Investigations that examine species composition over time and the differences between baits are discussed. (KR)

  15. Interchange mode excited by trapped energetic ions

    SciTech Connect

    Nishimura, Seiya

    2015-07-15

    The kinetic energy principle describing the interaction between ideal magnetohydrodynamic (MHD) modes with trapped energetic ions is revised. A model is proposed on the basis of the reduced ideal MHD equations for background plasmas and the bounce-averaged drift-kinetic equation for trapped energetic ions. The model is applicable to large-aspect-ratio toroidal devices. Specifically, the effect of trapped energetic ions on the interchange mode in helical systems is analyzed. Results show that the interchange mode is excited by trapped energetic ions, even if the equilibrium states are stable to the ideal interchange mode. The energetic-ion-induced branch of the interchange mode might be associated with the fishbone mode in helical systems.

  16. Metallic nano-particles for trapping light

    PubMed Central

    2013-01-01

    We study metallic nano-particles for light trapping by investigating the optical absorption efficiency of the hydrogenated amorphous silicon thin film with and without metallic nano-particles on its top. The size and shape of these nano-particles are investigated as to their roles of light trapping: scattering light to the absorption medium and converting light to surface plasmons. The optical absorption enhancement in the red light region (e.g., 650nm) due to the light trapping of the metallic nano-particles is observed when a layer of metallic nano-particle array has certain structures. The investigation of the light with incident angles shows the importance of the coupling efficiency of light to surface plasmons in the metallic nano-particle light trapping. PACS 73.20.Mf, 42.25.s, 88.40.hj PMID:23391493

  17. Are Your Steam Traps Leaking Money?

    ERIC Educational Resources Information Center

    American School and University, 1974

    1974-01-01

    Contends that small defects in steam heating systems often go unnoticed, while efficiency drops. Presents guidelines for detecting steam loss through trap orifices and determining how much they are costing. (Author/MLF)

  18. Molten Hydroxide Trapping Process for Radioiodine

    SciTech Connect

    Trowbridge, L.D.

    2003-01-28

    A molten hydroxide trapping process has been considered for removing radioiodine species from off-gas streams whereby iodine is reacted directly with molten hydroxides such as NaOH or KOH. The resulting product is the corresponding iodide, which can be separated by simple cooling of the molten mixture to grow the iodide primary phase once the mixture reaches 70-80 mol% in the iodide component. Thermodynamic analysis indicates that such a chemical process is highly favorable. Experimental testing of the trapping process using molecular iodine showed trapping of up to 96% of the volatile iodine. The trapping efficiency was dependent on operational parameters such as temperature and gas-melt contact efficiency, and higher efficiencies are expected as the process is further developed. While an iodide phase could be effectively isolated by slow cooling of a molten iodide-hydroxide mixture, the persistent appearance of hydroxide indicated that an appreciable solubility of hydroxide occurred in the iodide phase.

  19. Charged nanodiamonds in a Paul trap

    NASA Astrophysics Data System (ADS)

    Streed, Erik

    2015-05-01

    Colloidal nanodiamonds were ionized with atmospheric electrospray and loaded into a Paul trap. Fluorescence from atom-like NV0 and NV- colour centres has been observed. The very low intrinsic absorption of bulk diamond is favourable for reducing the heating of cooled, trapped, nanodiamond ions from the surrounding blackbody radiation of the trapping apparatus. The isolated environment of the ion trap is also favourable for in-situ modification of nanodiamond to reduce absorption inducing defects through either physical or chemical processes. The presence or intentional introduction of high luminescence atom-like colour centre defects such as NV or SiV offer the prospect of direct laser cooling in nanodiamonds with low emissivity. Such laser cooled nano-ions are of interest for sympathetically cooling ions of similar charge/mass ratios that lack closed optical transitions, such as large biomolecules. ARC Future Fellow.

  20. Doppler cooling and trapping on forbidden transitions.

    PubMed

    Binnewies, T; Wilpers, G; Sterr, U; Riehle, F; Helmcke, J; Mehlstäubler, T E; Rasel, E M; Ertmer, W

    2001-09-17

    Ultracold atoms at temperatures close to the recoil limit have been achieved by extending Doppler cooling to forbidden transitions. A cloud of (40)Ca atoms has been cooled and trapped to a temperature as low as 6 microK by operating a magnetooptical trap on the spin-forbidden intercombination transition. Quenching the long-lived excited state with an additional laser enhanced the scattering rate by a factor of 15, while a high selectivity in velocity was preserved. With this method, more than 10% of precooled atoms from a standard magnetooptical trap have been transferred to the ultracold trap. Monte Carlo simulations of the cooling process are in good agreement with the experiments. PMID:11580503

  1. Strongly trapped two-dimensional quantum walks

    NASA Astrophysics Data System (ADS)

    Kollár, B.; Kiss, T.; Jex, I.

    2015-02-01

    Discrete time quantum walks (DTQWs) are nontrivial generalizations of random walks with a broad scope of applications. In particular, they can be used as computational primitives, and they are suitable tools for simulating other quantum systems. DTQWs usually spread ballistically due to their quantumness. In some cases, however, they can remain localized at their initial state (trapping). The trapping and other fundamental properties of DTQWs are determined by the choice of the coin operator. We introduce and analyze a type of walks driven by a coin class leading to strong trapping, complementing the known list of walks. This class of walks exhibits a number of exciting properties with possible applications ranging from light pulse trapping in a medium to topological effects and quantum search.

  2. Trapped Electron Precession Shear Induced Fluctuation Decorrelation

    SciTech Connect

    T.S. Hahm; P.H. Diamond; E.-J. Kim

    2002-07-29

    We consider the effects of trapped electron precession shear on the microturbulence. In a similar way the strong E x B shear reduces the radial correlation length of ambient fluctuations, the radial variation of the trapped electron precession frequency can reduce the radial correlation length of fluctuations associated with trapped electrons. In reversed shear plasmas, with the explicit dependence of the trapped electron precession shearing rate on B(subscript)theta, the sharp radial gradient of T(subscript)e due to local electron heating inside qmin can make the precession shearing mechanism more effective, and reduce the electron thermal transport constructing a positive feedback loop for the T(subscript)e barrier formation.

  3. Antihydrogen Production, Trapping, and Antimatter Plasmas

    SciTech Connect

    Fajans, Joel

    2009-09-16

    Since 2002, experiments at CERN have been producing slow, but untrapped, antihydrogen. The ultimate goal of these experiments is to test CPT and the gravitational interactions of matter and antimatter. Most schemes to perform CPT and gravity tests require trapped antihydrogen, but trapping antihydrogen is much more difficult than merely synthesizing it. The principle problems that must be solved before we can trap are how to cool the antiprotons, and how to keep them cold during the synthesis process. While we have already learned how to cool antiprotons by ten orders of magnitude, we must cool them by four more orders of magnitude, a scale set by the relative size of the potentials of the antimatter plasmas from which the antiatoms are synthesized compared to the antihydrogen trap well depth. In this talk, I will discuss antihydrogen synthesis and some of the techniques we are developing to control the energy of the resultant antihydrogen.

  4. Rainbow Trapping in Hyperbolic Metamaterial Waveguide

    PubMed Central

    Hu, Haifeng; Ji, Dengxin; Zeng, Xie; Liu, Kai; Gan, Qiaoqiang

    2013-01-01

    The recent reported trapped “rainbow” storage of light using metamaterials and plasmonic graded surface gratings has generated considerable interest for on-chip slow light. The potential for controlling the velocity of broadband light in guided photonic structures opens up tremendous opportunities to manipulate light for optical modulation, switching, communication and light-matter interactions. However, previously reported designs for rainbow trapping are generally constrained by inherent difficulties resulting in the limited experimental realization of this intriguing effect. Here we propose a hyperbolic metamaterial structure to realize a highly efficient rainbow trapping effect, which, importantly, is not limited by those severe theoretical constraints required in previously reported insulator-negative-index-insulator, insulator-metal-insulator and metal-insulator-metal waveguide tapers, and therefore representing a significant promise to realize the rainbow trapping structure practically. PMID:23409240

  5. Trapping radioactive {sup 82}Rb in an optical dipole trap and evidence of spontaneous spin polarization

    SciTech Connect

    Feldbaum, D.; Wang, H.; Weinstein, J.; Vieira, D.; Zhao, X.

    2007-11-15

    Optical trapping of selected species of radioactive atoms has great potential in precision measurements for testing fundamental physics such as the electric dipole moment, atomic parity nonconservation, and parity-violating {beta}-decay correlation coefficients. We report on the trapping of 10{sup 4} radioactive {sup 82}Rb atoms (t{sub 1/2}=75 s) with a trap lifetime of {approx}55 s in an optical dipole trap. Transfer efficiency from the magneto-optical trap is {approx}14%. We further report evidence of spontaneous spin polarization of the atoms in optical dipole trap loading. These advancements are an important step toward a new generation of precision nuclear-spin-{beta}-emission direction correlation measurements with polarized {sup 82}Rb atoms.

  6. The lensing effect of trapped particles in a dual-beam optical trap.

    PubMed

    Grosser, Steffen; Fritsch, Anatol W; Kiessling, Tobias R; Stange, Roland; Käs, Josef A

    2015-02-23

    In dual-beam optical traps, two counterpropagating, divergent laser beams emitted from opposing laser fibers trap and manipulate dielectric particles. We investigate the lensing effect that trapped particles have on the beams. Our approach makes use of the intrinsic coupling of a beam to the opposing fiber after having passed the trapped particle. We present measurements of this coupling signal for PDMS particles, as well as a model for its dependence on size and refractive index of the trapped particle. As a more complex sample, the coupling of inhomogeneous biological cells is measured and discussed. We show that the lensing effect is well captured by the simple ray optics approximation. The measurements reveal intricate details, such as the thermal lens effect of the beam propagation in a dual-beam trap. For a particle of known size, the model further allows to infer its refractive index simply from the coupling signal. PMID:25836555

  7. Inhomogeneous electric field effects in a linear RF quadruple trap

    NASA Technical Reports Server (NTRS)

    Melborne, R. K.

    1990-01-01

    The exact potential corresponding to confining fields inside a linear rf quadrupole particle trap of finite length is presented. The analytic expressions for the trapping potential is derived by introducing a linear trap employing a relatively simple cylindrical geometry and solving Laplace's equation for the trap electrodes. The finite length of linear traps results in field distortion near the trap ends. An exact analytic determination of the fields is useful because the profile of the trapped ion cloud is highly dependent on the fields confining it. It is shown that near the ends of the trap, the effective potential arising from the rf fields acts to propel particles out of the trap, and further, that the addition of a dc bias generates an inhomogeneous in the trap that influences the particles both perpendicularly to and along the trap's long axis.

  8. Tandem Cycloisomerization/Suzuki Coupling of Arylethynyl MIDA Boronates

    PubMed Central

    Chan, Julian M. W.; Amarante, Giovanni W.; Toste, F. Dean

    2011-01-01

    A tandem gold-catalyzed cycloisomerization/Suzuki cross coupling sequence involving arylethynyl-N-methyliminodiacetic acid boronates is described. Combining the mildness of homogeneous gold catalysis with the versatility of N-methyliminodiacetic acid (MIDA) boronates, this tandem two-step method enables the rapid assembly of various aryl-substituted heterocycles without having to isolate or purify any heterocyclic MIDA boronate intermediates. Another major advantage of this method is that a wide range of heterocycles bearing different aryl groups may be made from a single MIDA boronate alkyne precursor. PMID:21765556

  9. Tandem riboswitch architectures exhibit complex gene control functions.

    PubMed

    Sudarsan, Narasimhan; Hammond, Ming C; Block, Kirsten F; Welz, Rüdiger; Barrick, Jeffrey E; Roth, Adam; Breaker, Ronald R

    2006-10-13

    Riboswitches are structured RNAs typically located in the 5' untranslated regions of bacterial mRNAs that bind metabolites and control gene expression. Most riboswitches sense one metabolite and function as simple genetic switches. However, we found that the 5' region of the Bacillus clausii metE messenger RNA includes two riboswitches that respond to S-adenosylmethionine and coenzyme B12. This tandem arrangement yields a composite gene control system that functions as a two-input Boolean NOR logic gate. These findings and the discovery of additional tandem riboswitch architectures reveal how simple RNA elements can be assembled to make sophisticated genetic decisions without involving protein factors. PMID:17038623

  10. Enclosed bark as a pollen trap

    USGS Publications Warehouse

    Adam, D.P.; Ferguson, C.W.; Lamarch, V.C., Jr.

    1967-01-01

    Counts were made of pollen in traps formed by enclosed bark in two remnants of bristlecone pine, Pinus aristata Engelm., from the White Mountains of east-central California. The traps, dated by tree-rings at A.D. 350 and 1300 B.C., contained a major complex of pine-sagebrush pollen and traces of other species, representing the equivalent of the present vegetation.

  11. Progress Towards Laser Cooling and Trapping Gadolinium

    NASA Astrophysics Data System (ADS)

    Adhikari, Upendra; Simien, Clayton

    2016-05-01

    Lanthanide elements are of interest because of their potential for investigating next generation optical clock transitions, novel non-S ground state ultracold collisions, and the physics of quantum degenerate dipolar gases. We present our progress towards laser cooling and trapping atomic Gadolinium (Gd). A magneto-optical trap is the first step towards precision measurements, ultracold collision studies, and for probing dipolar physics of Gd. The design, construction, and performance of the apparatus will be presented.

  12. Sorbents for Trapping Organic Pollutants From Air.

    PubMed

    Ligor; Gorecka; Buszewski

    1998-01-01

    A series of siliceous adsorbents with chemically bonded phases (CBPs) of different polarity were tested as sorbents for trapping air pollutants (petroleum ether) using controlled setup. Moreover, special attention was paid to the potential role of metal impurities as strong adsorption sites. Sorbents were characterized by various physico-chemical methods, such as porosimetry, inductively coupled plasma (ICP) analysis, elemental analysis, derivatography, and gas chromatography. Trapping tubes were utilized for sorption of toxic pollutants from indoor air. PMID:10602615

  13. Characterization of UVIS traps with CI

    NASA Astrophysics Data System (ADS)

    Sabbi, Elena

    2013-10-01

    The charge transfer efficiency {CTE} of the WFC3/UVIS channel is declining as damage from radiation is accumulating. The impact of CTE losses on scientific data can be mitigated by removing the charge-trailing at pixel level. This program is designed to identify and characterize the traps responsible for the charge losses and to monitor the grouth of the trap number with time.

  14. Kinetically Trapped Tetrahedral Cages via Alkyne Metathesis.

    PubMed

    Lee, Semin; Yang, Anna; Moneypenny, Timothy P; Moore, Jeffrey S

    2016-02-24

    In dynamic covalent synthesis, kinetic traps are perceived as disadvantageous, hindering the system from reaching its thermodynamic equilibrium. Here we present the near-quantitative preparation of tetrahedral cages from simple tritopic precursors using alkyne metathesis. While the cages are the presumed thermodynamic sink, we experimentally demonstrate that the products no longer exchange their vertices once they have formed. The example reported here illustrates that kinetically trapped products may facilitate high yields of complex products from dynamic covalent synthesis. PMID:26854552

  15. Nanostructured tapered optical fibers for paticle trapping

    NASA Astrophysics Data System (ADS)

    Daly, Mark; Truong, Viet Giang; Nic Chormaic, Síle

    2015-05-01

    Optical micro- and nanofibers have recently gained popularity as tools in quantum engineering using laser-cooled, neutral atoms. In particular, atoms can be trapped around such optical fibers, and photons coupled into the fibers from the surrounding atoms could be used to transfer quantum state information within the system. It has also been demonstrated that such fibers can be used to manipulate and trap silica and polystyrene particles in the 1-3 μm range. We recently proposed using a focused ion beam nanostructured tapered optical fiber for improved atom trapping geometries1. Here, we present details on the design and fabrication of these nanostructured optical fibers and their integration into particle trapping platforms for the demonstration of submicron particle trapping. The optical fibers are tapered to approximately 1-2 μm waist diameters, using a custom-built, heat-and-pull fiber rig, prior to processing using a focused ion beam. Slots of about 300 nm in width and 10-20 μm in length are milled right though the waist regions of the tapered optical fibers. Details on the fabrication steeps necessary to ensure high optical transmission though the fiber post processing are included. Fiber transmissions of over 80% over a broad range of wavelengths, in the 700-11100 nm range, are attainable. We also present simulation results on the impact of varying the slot parameters on the trap depths achievable and milling multiple traps within a single tapered fiber. This work demonstrates even further the functionality of optical micro- and nanofibers as trapping devices across a range of regimes.

  16. Trapped-Ion Optical Frequency Standards

    NASA Astrophysics Data System (ADS)

    Schmidt, Piet O.; Leroux, Ian D.

    Optical frequency standards based on trapped atoms are the most accurate measurement devices we have available. They not only serve as superior time keepers but also lend themselves to a wide variety of applications ranging from tests of fundamental physics to the measurement of heights in relativistic geodesy. This chapter provides an introduction to the basics of optical frequency standards and clocks based on trapped ions and their applications.

  17. On biodiversity conservation and poverty traps

    PubMed Central

    Barrett, Christopher B.; Travis, Alexander J.; Dasgupta, Partha

    2011-01-01

    This paper introduces a special feature on biodiversity conservation and poverty traps. We define and explain the core concepts and then identify four distinct classes of mechanisms that define important interlinkages between biodiversity and poverty. The multiplicity of candidate mechanisms underscores a major challenge in designing policy appropriate across settings. This framework is then used to introduce the ensuing set of papers, which empirically explore these various mechanisms linking poverty traps and biodiversity conservation. PMID:21873176

  18. A Distonic Radical-Ion for Detection of Traces of Adventitious Molecular Oxygen (O2) in Collision Gases Used in Tandem Mass Spectrometers

    NASA Astrophysics Data System (ADS)

    Jariwala, Freneil B.; Hibbs, John A.; Weisbecker, Carl S.; Ressler, John; Khade, Rahul L.; Zhang, Yong; Attygalle, Athula B.

    2014-09-01

    We describe a diagnostic ion that enables rapid semiquantitative evaluation of the degree of oxygen contamination in the collision gases used in tandem mass spectrometers. Upon collision-induced dissociation (CID), the m/z 359 positive ion generated from the analgesic etoricoxib undergoes a facile loss of a methyl sulfone radical [•SO2(CH3); 79-Da] to produce a distonic radical cation of m/z 280. The product-ion spectrum of this m/z 280 ion, recorded under low-energy activation on tandem-in-space QqQ or QqTof mass spectrometers using nitrogen from a generator as the collision gas, or tandem-in-time ion-trap (LCQ, LTQ) mass spectrometers using purified helium as the buffer gas, showed two unexpected peaks at m/z 312 and 295. This enigmatic m/z 312 ion, which bears a mass-to-charge ratio higher than that of the precursor ion, represented an addition of molecular oxygen (O2) to the precursor ion. The exceptional affinity of the m/z 280 radical cation towards oxygen was deployed to develop a method to determine the oxygen content in collision gases.

  19. Ultra-fast underwater suction traps

    PubMed Central

    Vincent, Olivier; Weißkopf, Carmen; Poppinga, Simon; Masselter, Tom; Speck, Thomas; Joyeux, Marc; Quilliet, Catherine; Marmottant, Philippe

    2011-01-01

    Carnivorous aquatic Utricularia species catch small prey animals using millimetre-sized underwater suction traps, which have fascinated scientists since Darwin's early work on carnivorous plants. Suction takes place after mechanical triggering and is owing to a release of stored elastic energy in the trap body accompanied by a very fast opening and closing of a trapdoor, which otherwise closes the trap entrance watertight. The exceptional trapping speed—far above human visual perception—impeded profound investigations until now. Using high-speed video imaging and special microscopy techniques, we obtained fully time-resolved recordings of the door movement. We found that this unique trapping mechanism conducts suction in less than a millisecond and therefore ranks among the fastest plant movements known. Fluid acceleration reaches very high values, leaving little chance for prey animals to escape. We discovered that the door deformation is morphologically predetermined, and actually performs a buckling/unbuckling process, including a complete trapdoor curvature inversion. This process, which we predict using dynamical simulations and simple theoretical models, is highly reproducible: the traps are autonomously repetitive as they fire spontaneously after 5–20 h and reset actively to their ready-to-catch condition. PMID:21325323

  20. The Electronic McPhail Trap

    PubMed Central

    Potamitis, Ilyas; Rigakis, Iraklis; Fysarakis, Konstantinos

    2014-01-01

    Certain insects affect cultivations in a detrimental way. A notable case is the olive fruit fly (Bactrocera oleae (Rossi)), that in Europe alone causes billions of euros in crop-loss/per year. Pests can be controlled with aerial and ground bait pesticide sprays, the efficiency of which depends on knowing the time and location of insect infestations as early as possible. The inspection of traps is currently carried out manually. Automatic monitoring traps can enhance efficient monitoring of flying pests by identifying and counting targeted pests as they enter the trap. This work deals with the hardware setup of an insect trap with an embedded optoelectronic sensor that automatically records insects as they fly in the trap. The sensor responsible for detecting the insect is an array of phototransistors receiving light from an infrared LED. The wing-beat recording is based on the interruption of the emitted light due to the partial occlusion from insect's wings as they fly in the trap. We show that the recordings are of high quality paving the way for automatic recognition and transmission of insect detections from the field to a smartphone. This work emphasizes the hardware implementation of the sensor and the detection/counting module giving all necessary implementation details needed to construct it. PMID:25429412