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Sample records for large volume czt

  1. Annealing as grown large volume CZT single crystals increased spectral resolution

    SciTech Connect

    Dr. Longxia Li

    2008-03-19

    The spectroscopic performance of current large-volume Cadmium 10% Zinc Telluride, Cd{sub 0.9}Zn{sub 0.1}Te, (CZT) detectors is impaired by cumulative effect of tellurium precipitates (secondary phases) presented in CZT single-crystal grown by low-pressure Bridgman techniques(1). This statistical effect may limit the energy resolution of large-volume CZT detectors (typically 2-5% at 662 keV for 12-mm thick devices). The stochastic nature of the interaction prevents the use of any electronic or digital charge correction techniques without a significant reduction in the detector efficiency. This volume constraint hampers the utility of CZT since the detectors are inefficient at detecting photons >1MeV and/or in low fluency situations. During the project, seven runs CZT ingots have been grown, in these ingots the indium dopant concentrations have been changed in the range between 0.5ppm to 6ppm. The I-R mapping imaging method has been employed to study the Te-precipitates. The Teprecipitates in as-grown CZT wafers, and after annealing wafers have been systematically studied by using I-R mapping system (home installed, resolution of 1.5 {micro}m). We employed our I-R standard annealing CZT (Zn=4%) procedure or two-steps annealing into radiation CZT (Zn=10%), we achieved the 'non'-Te precipitates (size < 1 {micro}m) CZT n+-type with resistivity > 10{sup 9-10} {Omega}-cm. We believe that the Te-precipitates are the p-type defects, its reducing number causes the CZT became n+-type, therefore we varied or reduced the indium dapant concentration during the growth and changed the Te-precipitates size and density by using different Cd-temperature and different annealing procedures. We have made the comparisons among Te-precipitates size, density and Indium dopant concentrations, and we found that the CZT with smaller size of Te-precipitates is suitable for radiation uses but non-Te precipitates is impossible to be used in the radiation detectors, because the CZT would became

  2. Exploring the limiting timing resolution for large volume CZT detectors with waveform analysis

    PubMed Central

    Meng, L.J.; He, Z.

    2016-01-01

    This paper presents a study for exploring the limiting timing resolution that can be achieved with a large volume 3-D position sensitive CZT detector. The interaction timing information was obtained by fitting the measured cathode waveforms to pre-defined waveform models. We compared the results from using several different waveform models. Timing resolutions, of ~9.5 ns for 511 keV full-energy events and ~11.6 ns for all detected events with energy deposition above 250 keV, were achieved with a detailed modeling of the cathode waveform as a function of interaction location and energy deposition. This detailed modeling also allowed us to derive a theoretical lower bound for the error on estimated interaction timing. Both experimental results and theoretical predications matched well, which indicated that the best timing resolution achievable in the 1 cm3 CZT detector tested is ~10 ns. It is also showed that the correlation between sampled amplitudes in cathode waveforms is an important limiting factor for the achievable timing resolution. PMID:28260808

  3. Determination of 235U enrichment with a large volume CZT detector

    NASA Astrophysics Data System (ADS)

    Mortreau, Patricia; Berndt, Reinhard

    2006-01-01

    Room-temperature CdZnTe and CdTe detectors have been routinely used in the field of Nuclear Safeguards for many years [Ivanov et al., Development of large volume hemispheric CdZnTe detectors for use in safeguards applications, ESARDA European Safeguards Research and Development Association, Le Corum, Montpellier, France, 1997, p. 447; Czock and Arlt, Nucl. Instr. and Meth. A 458 (2001) 175; Arlt et al., Nucl. Instr. and Meth. A 428 (1999) 127; Lebrun et al., Nucl. Instr. and Meth. A 448 (2000) 598; Aparo et al., Development and implementation of compact gamma spectrometers for spent fuel measurements, in: Proceedings, 21st Annual ESARDA, 1999; Arlt and Rudsquist, Nucl. Instr. and Meth. A 380 (1996) 455; Khusainov et al., High resolution pin type CdTe detectors for the verification of nuclear material, in: Proceedings, 17th Annual ESARDA European Safeguards Research and Development Association, 1995; Mortreau and Berndt, Nucl. Instr. and Meth. A 458 (2001) 183; Ruhter et al., UCRL-JC-130548, 1998; Abbas et al., Nucl. Instr. and Meth. A 405 (1998) 153; Ruhter and Gunnink, Nucl. Instr. and Meth. A 353 (1994) 716]. Due to their performance and small size, they are ideal detectors for hand-held applications such as verification of spent and fresh fuel, U/Pu attribute tests as well as for the determination of 235U enrichment. The hemispherical CdZnTe type produced by RITEC (Riga, Latvia) [Ivanov et al., 1997] is the most widely used detector in the field of inspection. With volumes ranging from 2 to 1500 mm 3, their spectral performance is such that the use of electronic processing to correct the pulse shape is not required. This paper reports on the work carried out with a large volume (15×15×7.5 mm 3) and high efficiency hemispherical CdZnTe detector for the determination of 235U enrichment. The measurements were made with certified uranium samples whose enrichment ranging from 0.31% to 92.42%, cover the whole range of in-field measurement conditions. The interposed

  4. Development of large-area CZT detector systems

    NASA Astrophysics Data System (ADS)

    Kuvvetli, Irfan; Budtz-Joergensen, Carl C.; Westergaard, Niels J.; Jonasson, Per; van Pamelen, Mike A.; Reglero, Victor; Eyles, Christopher J.; Neubert, Torsten

    1999-10-01

    DSRI has initiated a development program of CZT x-ray and gamma ray detectors employing strip readout techniques. A dramatic improvement of the energy response was found operating the detectors as so-called drift detectors. For the electronic readout, modern ASIC chips were investigated. Modular design and the low power electronics will make large area detectors using the drift strip method feasible. The performance of a prototype CZT system will be presented and discussed.

  5. Experimental measurements of charge carrier mobility: lifetime products for large sample of pixilated CZT detectors

    NASA Astrophysics Data System (ADS)

    Vadawale, S. V.; Shanmugam, M.; Purohit, Shishir; Acharya, Y. B.; Sudhakar, Manju

    2012-07-01

    Cadmium-Zinc-Telluride (CZT) is thought to be a primary work horse for hard X-ray astronomy in future. Due to the relatively large band-gap, it offers near room temperature operation while maintaining much better energy resolution then scintillator detectors operating in similar energy range. Further, CZT detectors are available in the form of pixilated detectors with area up to few cm2 and hence it is possible to realize very large detector area by having an array of such pixilated CZT detectors. However, it is well known that the energy spectrum of mono-energetic X-ray measured by CZT detectors does not have a Gaussian shape but has significant low-energy tail. This is mainly due to relatively poor mobility and small life time of the charge carriers, particularly of holes, in the CZT crystals. Thus, in order to understand spectral response for a large array of CZT detectors consisting of multiple elements / pixels, it is essential to characterize the mobility-lifetime products of charge carriers for each individual elements / pixels. Here we present experimental measurements of charge carrier mobility-lifetime products for large sample of multi-pixel CZT detectors. The mobility-lifetime products are measured by simultaneously fitting a ‘CZT line’ model to pixel wise spectra of 122 keV X-rays from 57Co at three different bias voltages. These were carried out as a part of selection of CZT detector modules for the “High Energy X-ray spectrometer (HEX)” onboard Indian moon mission - Chandrayaan-1.

  6. Improved CZT for Gamma Detection

    SciTech Connect

    JAMES, R.

    2015-03-16

    The goal of the project is to advance the state of the art for spectroscopic and imaging detectors for nonproliferation uses by developing a fundamental understanding of defects limiting the performance of large-volume CZT detectors and fixing them, and increasing the detector size and electron mobility-lifetime product while reducing the cost of detector-grade crystals. Interaction points can be precisely determined in 3D for CZT detectors.

  7. Large dynamic range 64-channel ASIC for CZT or CdTe detectors

    NASA Astrophysics Data System (ADS)

    Glasser, F.; Villard, P.; Rostaing, J. P.; Accensi, M.; Baffert, N.; Girard, J. L.

    2003-08-01

    We present a customized 64-channel ASIC, named ALIX, developed in a 0.8 μm CMOS technology. This circuit is dedicated to measure charges from semi-conductor X-ray detectors like Cadmium Zinc Telluride (CZT) or Cadmium Telluride CdTe. The specificity of ALIX is to be able to measure charges over a very large dynamic range (from 10 fC to 3 nC), and to store eight measurements in a very short time (from every 250 ns to a few ms). Up to eight images are stored inside the ASIC and each image can be read out in 64 μs. A new acquisition sequence can then be started. Two analog readouts are available, one for the X-ray signal and one for the offset and afterglow measurement in case of pulsed X-rays. The outputs are converted into digital values by two off-chip 14 bits Analog-to-Digital Converters (ADC). A first version of ALIX has been tested with CZT and CdTe detectors under high-energy pulsed X-ray photons (20 MeV, 60 ns pulses every 250 ns). We will present the different results of linearity and signal-to-noise ratio. A second version of ALIX has been designed with some corrections. Electrical tests performed on 85 ASICS showed that the corrections were successful. We are now able to integrate them behind a 64×32 pixels 1 mm pitch CZT detector. Such an ASIC could also be used for strip detectors where a large dynamic range and a fast response are necessary.

  8. Multi-Element CZT Array for Nuclear Safeguards Applications

    NASA Astrophysics Data System (ADS)

    Kwak, S.-W.; Lee, A.-R.; Shin, J.-K.; Park, U.-R.; Park, S.; Kim, Y.; Chung, H.

    2016-12-01

    Due to its electronic properties, a cadmium zinc telluride (CZT) detector has been used as a hand-held portable nuclear measurement instrument. However, a CZT detector has low detection efficiency because of a limitation of its single crystal growth. To address its low efficiency, we have constructed a portable four-CZT array based gamma-ray spectrometer consisting of a CZT array, electronics for signal processing and software. Its performance has been characterized in terms of energy resolution and detection efficiency using radioactive sources and nuclear materials. Experimental results showed that the detection efficiency of the four-CZT array based gamma-ray spectrometer was much higher than that of a single CZT detector in the array. The FWHMs of the CZT array were 9, 18, and 21 keV at 185.7, 662, and 1,332 keV, respectively. Some gamma-rays in a range of 100 keV to 200 keV were not clear in a single crystal detector while those from the CZT array system were observed to be clear. The energy resolution of the CZT array system was only slightely worse than those of the single CZT detectors. By combining several single crystals and summing signals from each single detector at a digital electronic circuit, the detection efficiency of a CZT array system increased without degradation of its energy resolution. The technique outlined in this paper shows a very promising method for designing a CZT-based gamma-ray spectroscopy that overcomes the fundamental limitations of a small volume CZT detector.

  9. Handheld CZT radiation detector

    DOEpatents

    Murray, William S.; Butterfield, Kenneth B.; Baird, William

    2004-08-24

    A handheld CZT radiation detector having a CZT gamma-ray sensor, a multichannel analyzer, a fuzzy-logic component, and a display component is disclosed. The CZT gamma-ray sensor may be a coplanar grid CZT gamma-ray sensor, which provides high-quality gamma-ray analysis at a wide range of operating temperatures. The multichannel analyzer categorizes pulses produce by the CZT gamma-ray sensor into channels (discrete energy levels), resulting in pulse height data. The fuzzy-logic component analyzes the pulse height data and produces a ranked listing of radioisotopes. The fuzzy-logic component is flexible and well-suited to in-field analysis of radioisotopes. The display component may be a personal data assistant, which provides a user-friendly method of interacting with the detector. In addition, the radiation detector may be equipped with a neutron sensor to provide an enhanced mechanism of sensing radioactive materials.

  10. CZT Virtual Frisch-grid Detector: Principles and Applications

    SciTech Connect

    Cui,Y.; Bolotnikov, A.; Camarda, G.; Hossain, A.; James, R. B.

    2009-03-24

    Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for using as room-temperature semiconductor detectors, because it has a wide bandgap and a high atomic number. However, due to the material's poor hole mobility, several special techniques were developed to ensure its suitability for radiation detection. Among them, the virtual Frisch-grid CZT detector is an attractive option, having a simple configuration, yet delivering an outstanding spectral performance. The goal of our group in Brookhaven National Laboratory (BNL) is to improve the performance of Frisch-ring CZT detectors; most recently, that effort focused on the non-contacting Frisch-ring detector, allowing us to build an inexpensive, large-volume detector array with high energy-resolution and a large effective area. In this paper, the principles of virtual Frisch-grid detectors are described, especially BNL's innovative improvements. The potential applications of virtual Frisch-grid detectors are discussed, and as an example, a hand-held gamma-ray spectrometer using a CZT virtual Frischgrid detector array is introduced, which is a self-contained device with a radiation detector, readout circuit, communication circuit, and high-voltage supply. It has good energy resolution of 1.4% (FWHM of 662-keV peak) with a total detection volume of {approx}20 cm{sup 3}. Such a portable inexpensive device can be used widely in nonproliferation applications, non-destructive detection, radiation imaging, and for homeland security. Extended systems based on the same technology have potential applications in industrial- and nuclear-medical-imaging.

  11. Cathode depth sensing in CZT detectors

    NASA Astrophysics Data System (ADS)

    Hong, JaeSub; Bellm, Eric C.; Grindlay, Jonathan E.; Narita, Tomohiko

    2004-02-01

    Measuring the depth of interaction in thick Cadmium-Zinc-Telluride (CZT) detectors allows improved imaging and spectroscopy for hard X-ray imaging above 100 keV. The Energetic X-ray Imaging Survey Telescope (EXIST) will employ relatively thick (5 - 10 mm) CZT detectors, which are required to perform the broad energy-band sky survey. Interaction depth information is needed to correct events to the detector "focal plane" for correct imaging and can be used to improve the energy resolution of the detector at high energies by allowing event-based corrections for incomplete charge collection. Background rejection is also improved by allowing low energy events from the rear and sides of the detector to be rejected. We present experimental results of intereaction depth sensing in a 5 mm thick pixellated Au-contact IMARAD CZT detector. The depth sensing was done by making simultaneous measurements of cathode and anode signals, where the interaction depth at a given energy is proportional to the ratio of cathode/anode signals. We demonstrate how a simple empirical formula describing the event distributions in the cathode/anode signal space can dramatically improve the energy resolution. We also estimate the energy and depth resolution of the detector as a function of the energy and the interaction depth. We also show a depth-sensing prototype system currently under development for EXIST in which cathode signals from 8, 16 or 32 crystals can be read-out by a small multi-channel ASIC board that is vertically edge-mounted on the cathode electrode along every second CZT crystal boundary. This allows CZT crystals to be tiled contiguously with minimum impact on throughput of incoming photons. The robust packaging is crucial in EXIST, which will employ very large area imaging CZT detector arrays.

  12. Improved x-ray spectroscopy with room temperature CZT detectors.

    PubMed

    Fritz, Shannon G; Shikhaliev, Polad M; Matthews, Kenneth L

    2011-09-07

    Compact, room temperature x-ray spectroscopy detectors are of interest in many areas including diagnostic x-ray imaging, radiation protection and dosimetry. Room temperature cadmium zinc telluride (CZT) semiconductor detectors are promising candidates for these applications. One of the major problems for CZT detectors is low-energy tailing of the energy spectrum due to hole trapping. Spectral post-correction methods to correct the tailing effect do not work well for a number of reasons; thus it is advisable to eliminate the hole trapping effect in CZT using physical methods rather than correcting an already deteriorated energy spectrum. One method is using a CZT detector with an electrode configuration which modifies the electric field in the CZT volume to decrease low-energy tailing. Another method is to irradiate the CZT surface at a tilted angle, which modifies depth of interaction to decrease low-energy tailing. Neither method alone, however, eliminates the tailing effect. In this work, we have investigated the combination of modified electric field and tilted angle irradiation in a single detector to further decrease spectral tailing. A planar CZT detector with 10 × 10 × 3 mm³ size and CZT detector with 5 × 5 × 5 mm³ size and cap-shaped electrode were used in this study. The cap-shaped electrode (referred to as CAPture technology) modifies the electric field distribution in the CZT volume and decreases the spectral tailing effect. The detectors were investigated at 90° (normal) and 30° (tilted angle) irradiation modes. Two isotope sources with 59.6 and 122 keV photon energies were used for gamma-ray spectroscopy experiments. X-ray spectroscopy was performed using collimated beams at 60, 80 and 120 kVp tube voltages, in both normal and tilted angle irradiation. Measured x-ray spectra were corrected for K x-ray escape fractions that were calculated using Monte Carlo methods. The x-ray spectra measured with tilted angle CAPture detector at 60, 80 and 120

  13. Characterization of front-end electronics for CZT based handheld radioisotope identifier

    NASA Astrophysics Data System (ADS)

    Lombigit, L.; Rahman, Nur Aira Abd; Mohamad, Glam Hadzir Patai; Ibrahim, Maslina Mohd; Yussup, Nolida; Yazid, Khairiah; Jaafar, Zainudin

    2016-01-01

    A radioisotope identifier device based on large volume Co-planar grid CZT detector is current under development at Malaysian Nuclear Agency. This device is planned to be used for in-situ identification of radioisotopes based on their unique energies. This work reports on electronics testing performed on the front-end electronics (FEE) analog section comprising charge sensitive preamplifier-pulse shaping amplifier chain. This test involves measurement of charge sensitivity, pulse parameters and electronics noise. This report also present some preliminary results on the spectral measurement obtained from gamma emitting radioisotopes.

  14. Characterization of front-end electronics for CZT based handheld radioisotope identifier

    SciTech Connect

    Lombigit, L.; Rahman, Nur Aira Abd; Mohamad, Glam Hadzir Patai; Ibrahim, Maslina Mohd; Yussup, Nolida; Yazid, Khairiah; Jaafar, Zainudin

    2016-01-22

    A radioisotope identifier device based on large volume Co-planar grid CZT detector is current under development at Malaysian Nuclear Agency. This device is planned to be used for in-situ identification of radioisotopes based on their unique energies. This work reports on electronics testing performed on the front-end electronics (FEE) analog section comprising charge sensitive preamplifier-pulse shaping amplifier chain. This test involves measurement of charge sensitivity, pulse parameters and electronics noise. This report also present some preliminary results on the spectral measurement obtained from gamma emitting radioisotopes.

  15. The Protoexist2 Advanced CZT Coded Aperture Telescope

    NASA Astrophysics Data System (ADS)

    Allen, Branden; Hong, J.; Grindlay, J.; Barthelmy, S.; Baker, R.

    2011-09-01

    The ProtoEXIST program was conceived for the development of a scalable detector plane architecture utilizing pixilated CdZnTe (CZT) detectors for eventual deployment in a large scale (1-4 m2 active area) coded aperture X-ray telescope for use as a wide field ( 90° × 70° FOV) all sky monitor and survey instrument for the 5 up to 600 keV energy band. The first phase of the program recently concluded with the successful 6 hour high altitude (39 km) flight of ProtoEXIST1, which utilized a closely tiled 8 × 8 array of 20 mm × 20 mm, 5 mm thick Redlen CZT crystals each bonded to a RadNET asic via an interposer board. Each individual CZT crystal utilized a 8 × 8 pixilated anode for the creation of a position sensitive detector with 2.5 mm spatial resolution. Development of ProtoEXIST2, the second advanced CZT detector plane in this series, is currently under way. ProtoEXIST2 will be composed of a closely tiled 8 × 8 array of 20 mm × 20 mm, 5 mm thick Redlen CZT crystals, similar to ProtoEXIST1, but will now utilize the Nu-ASIC which accommodates the direct bonding of CZT detectors with a 32 × 32 pixilated anode with a 604.8 μm pixel pitch. Characterization and performance of the ProtoEXIST2 detectors is discussed as well as current progress in the integration of the ProtoEXIST2 detector plane.

  16. Large volume manufacture of dymalloy

    SciTech Connect

    1998-06-22

    The purpose of this research was to test the commercial viability and feasibility of Dymalloy, a composite material to measure thermal conductivity. Dymalloy was developed as part of a CRADA with Sun Microsystems. Sun Microsystems was a potential end user of Dymalloy as a substrate for MCMS. Sun had no desire to be involved in the manufacture of this material. The goal of this small business CRADA with Spectra Mat was to establish the high volume commercial manufacturing industry source for Dymalloy required by an end-user such as Sun Microsystems. The difference between the fabrication technique developed during the CRADA and this proposed work related to the mechanical technique of coating the diamond powder. Mechanical parts for the high-volume diamond powder coating process existed; however, they needed to be installed in an existing coating system for evaluation. Sputtering systems similar to the one required for this project were available at LLNL. Once the diamond powder was coated, both LLNL and Spectra Mat could make and test the Dymalloy composites. Spectra Mat manufactured Dymalloy composites in order to evaluate and establish a reasonable cost estimate on their existing processing capabilities. This information was used by Spectra Mat to define the market and cost-competitive products that could be commercialized from this new substrate material.

  17. CZT sensors for Computed Tomography: from crystal growth to image quality

    NASA Astrophysics Data System (ADS)

    Iniewski, K.

    2016-12-01

    Recent advances in Traveling Heater Method (THM) growth and device fabrication that require additional processing steps have enabled to dramatically improve hole transport properties and reduce polarization effects in Cadmium Zinc Telluride (CZT) material. As a result high flux operation of CZT sensors at rates in excess of 200 Mcps/mm2 is now possible and has enabled multiple medical imaging companies to start building prototype Computed Tomography (CT) scanners. CZT sensors are also finding new commercial applications in non-destructive testing (NDT) and baggage scanning. In order to prepare for high volume commercial production we are moving from individual tile processing to whole wafer processing using silicon methodologies, such as waxless processing, cassette based/touchless wafer handling. We have been developing parametric level screening at the wafer stage to ensure high wafer quality before detector fabrication in order to maximize production yields. These process improvements enable us, and other CZT manufacturers who pursue similar developments, to provide high volume production for photon counting applications in an economically feasible manner. CZT sensors are capable of delivering both high count rates and high-resolution spectroscopic performance, although it is challenging to achieve both of these attributes simultaneously. The paper discusses material challenges, detector design trade-offs and ASIC architectures required to build cost-effective CZT based detection systems. Photon counting ASICs are essential part of the integrated module platforms as charge-sensitive electronics needs to deal with charge-sharing and pile-up effects.

  18. Simulating cosmic reionization: how large a volume is large enough?

    NASA Astrophysics Data System (ADS)

    Iliev, Ilian T.; Mellema, Garrelt; Ahn, Kyungjin; Shapiro, Paul R.; Mao, Yi; Pen, Ue-Li

    2014-03-01

    We present the largest-volume (425 Mpc h-1 = 607 Mpc on a side) full radiative transfer simulation of cosmic reionization to date. We show that there is significant additional power in density fluctuations at very large scales. We systematically investigate the effects this additional power has on the progress, duration and features of reionization and on selected reionization observables. We find that comoving volume of ˜100 Mpc h-1 per side is sufficient for deriving a convergent mean reionization history, but that the reionization patchiness is significantly underestimated. We use jackknife splitting to quantify the convergence of reionization properties with simulation volume. We find that sub-volumes of ˜100 Mpc h-1 per side or larger yield convergent reionization histories, except for the earliest times, but smaller volumes of ˜50 Mpc h-1 or less are not well converged at any redshift. Reionization history milestones show significant scatter between the sub-volumes, as high as Δz ˜ 1 for ˜50 Mpc h-1 volumes. If we only consider mean-density sub-regions the scatter decreases, but remains at Δz ˜ 0.1-0.2 for the different size sub-volumes. Consequently, many potential reionization observables like 21-cm rms, 21-cm PDF skewness and kurtosis all show good convergence for volumes of ˜200 Mpc h-1, but retain considerable scatter for smaller volumes. In contrast, the three-dimensional 21-cm power spectra at large scales (k < 0.25 h Mpc-1) do not fully converge for any sub-volume size. These additional large-scale fluctuations significantly enhance the 21-cm fluctuations, which should improve the prospects of detection considerably, given the lower foregrounds and greater interferometer sensitivity at higher frequencies.

  19. Position-sensitive CZT detector module

    NASA Astrophysics Data System (ADS)

    Matteson, James L.; Duttweiler, Fred; Huszar, George L.; Leblanc, Philippe C.; Skelton, Robert E.; Stephan, Edwin A.; Hink, Paul L.; Dowkontt, Paul F.; Slavis, Kimberly R.; Tumer, Tumay O.; Kravis, Scott D.

    1998-07-01

    Coded mask imagers for future high energy x-ray astronomy missions will require detector planes with areas of hundreds to thousands of cm(superscript 2) and position resolutions < 1 mm. Such detectors will enable coded mask imagers to discover and study thousands of high energy x-ray sources. The UCSD/WU/UCR/NOVA collaboration has been developing CZT detector systems with crossed-strip readout to meet these requirements. We report progress on a compact detector module with 41 cm(superscript 2) area and 0.5 mm spatial resolution. The design includes the bias network and ASIC readout electronics, and allows modules to be combined in large area arrays with very high live-area factors. Results from laboratory and balloon flight tests are presented.

  20. Large volume flow-through scintillating detector

    DOEpatents

    Gritzo, Russ E.; Fowler, Malcolm M.

    1995-01-01

    A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

  1. The CZT X-ray Imager on AXO

    NASA Astrophysics Data System (ADS)

    Budtz-Jørgensen, C.; Kuvvetli, I.; Westergaard, N. J.; Jonasson, P.; Reglero, V.; Eyles, C.; Neubert, T.

    2001-03-01

    DSRI has initiated a development program of CZT X-ray and gamma ray detectors employing strip readout techniques. A dramatic improvement of the energy response was found operating the detectors as so-called drift detectors. For the electronic readout, modern ASIC chips were investigated. Modular design and the low power electronics will make large area detectors using the drift strip method feasible. The performance of a prototype CZT system will be presented and discussed. One such detector system has been proposed for future space missions: The X-Ray Imager (XRI) on the Atmospheric X-ray Observatory (AXO), which is a mission proposed to the Danish Small Satellite Program and is dedicated to observations of X-ray generating processes in the Earth's atmosphere. Of special interest will be simultaneous optical and X-ray observations of sprites that are flashes appearing directly above an active thunderstorm system. Additional objective is a detailed mapping of the auroral X-ray and optical emission. XRI comprises a coded mask and a 20 cm × 40 cm CZT detector array covering an energy range from 5 to 200 keV.

  2. CZT vs FFT: Flexibility vs Speed

    SciTech Connect

    S. Sirin

    2003-10-01

    Bluestein's Fast Fourier Transform (FFT), commonly called the Chirp-Z Transform (CZT), is a little-known algorithm that offers engineers a high-resolution FFT combined with the ability to specify bandwidth. In the field of digital signal processing, engineers are always challenged to detect tones, frequencies, signatures, or some telltale sign that signifies a condition that must be indicated, ignored, or controlled. One of these challenges is to detect specific frequencies, for instance when looking for tones from telephones or detecting 60-Hz noise on power lines. The Goertzel algorithm described in Embedded Systems Programming, September 2002, offered a powerful tool toward finding specific frequencies faster than the FFT.Another challenge involves analyzing a range of frequencies, such as recording frequency response measurements, matching voice patterns, or displaying spectrum information on the face of an amateur radio. To meet this challenge most engineers use the well-known FFT. The CZT gives the engineer the flexibility to specify bandwidth and outputs real and imaginary frequency components from which the magnitude and phase can be computed. A description of the CZT and a discussion of the advantages and disadvantages of CZT versus the FFT and Goertzel algorithms will be followed by situations in which the CZT would shine. The reader will find that the CZT is very useful but that flexibility has a price.

  3. Safety considerations in large-volume lipoplasty.

    PubMed

    Giese, S Y

    2001-11-01

    Proper patient selection, diligent fluid management, and attention to body temperature are important safety considerations in large-volume lipoplasty (LVL). Complications related to fluid overload, lidocaine toxicity, coagulopathies, and lengthy combined surgical procedures are preventable and not directly linked to LVL technique. Benefits as well as morbidity and mortality from LVL can be weighed against risk factors such as obesity, a prediabetic condition, and/or adverse effects of weight-loss medications. The author describes how she incorporates safeguards into her LVL procedures. (Aesthetic Surg J 2001;21:545-548.).

  4. Tilted angle CZT detector for photon counting/energy weighting x-ray and CT imaging.

    PubMed

    Shikhaliev, Polad M

    2006-09-07

    X-ray imaging with a photon counting/energy weighting detector can provide the highest signal to noise ratio (SNR). Scanning slit/multi-slit x-ray image acquisition can provide a dose-efficient scatter rejection, which increases SNR. Use of a photon counting/energy weighting detector in a scanning slit/multi-slit acquisition geometry could provide highest possible dose efficiency in x-ray and CT imaging. Currently, the most advanced photon counting detector is the cadmium zinc telluride (CZT) detector, which, however, is suboptimal for energy resolved x-ray imaging. A tilted angle CZT detector is proposed in this work for applications in photon counting/energy weighting x-ray and CT imaging. In tilted angle configuration, the x-ray beam hits the surface of the linear array of CZT crystals at a small angle. This allows the use of CZT crystals of a small thickness while maintaining the high photon absorption. Small thickness CZT detectors allow for a significant decrease in the polarization effect in the CZT volume and an increase in count rate. The tilted angle CZT with a small thickness also provides higher spatial and energy resolution, and shorter charge collection time, which potentially enables fast energy resolving x-ray image acquisition. In this work, the major performance parameters of the tilted angle CZT detector, including its count rate, spatial resolution and energy resolution, were evaluated. It was shown that for a CZT detector with a 0.7 mm thickness and 13 degrees tilting angle, the maximum count rate can be increased by 10.7 times, while photon absorption remains >90% at photon energies up to 120 keV. Photon counting/energy weighting x-ray imaging using a tilted angle CZT detector was simulated. SNR improvement due to optimal photon energy weighting was 23% and 14% when adipose contrast element, inserted in soft tissue with 10 cm and 20 cm thickness, respectively, was imaged using 5 energy bins and weighting factors optimized for the adipose. SNR

  5. Multi-element CZT array for nuclear safeguards applications

    SciTech Connect

    Sung-Woo Kwak; Jung-Ki Shin; Seunghoon Park; Heejun Chung; Yongkwon Kim

    2015-07-01

    To address drawbacks of a CZT detector due to its limited size, a dual-CZT array, consisting of two CZT detectors and a DAS (Data Acquisition System), was constructed and algorithm to handle the spectra from the CZT array was discussed in this study. Spectra of 4.5% enriched UO{sub 2} powder were obtained using the dual-CZT array. The detection efficiency acquired by the CZT array was about twice higher than that of a single CZT spectra, while FWHMs are nearly identical (about 7.0 keV) for each spectrum. The results of this study show that a much better detection efficiency of CZT can be achieved without degrading its energy resolution. (authors)

  6. LARGE volume string compactifications at finite temperature

    SciTech Connect

    Anguelova, Lilia; Calò, Vincenzo; Cicoli, Michele E-mail: v.calo@qmul.ac.uk

    2009-10-01

    We present a detailed study of the finite-temperature behaviour of the LARGE Volume type IIB flux compactifications. We show that certain moduli can thermalise at high temperatures. Despite that, their contribution to the finite-temperature effective potential is always negligible and the latter has a runaway behaviour. We compute the maximal temperature T{sub max}, above which the internal space decompactifies, as well as the temperature T{sub *}, that is reached after the decay of the heaviest moduli. The natural constraint T{sub *} < T{sub max} implies a lower bound on the allowed values of the internal volume V. We find that this restriction rules out a significant range of values corresponding to smaller volumes of the order V ∼ 10{sup 4}l{sub s}{sup 6}, which lead to standard GUT theories. Instead, the bound favours values of the order V ∼ 10{sup 15}l{sub s}{sup 6}, which lead to TeV scale SUSY desirable for solving the hierarchy problem. Moreover, our result favours low-energy inflationary scenarios with density perturbations generated by a field, which is not the inflaton. In such a scenario, one could achieve both inflation and TeV-scale SUSY, although gravity waves would not be observable. Finally, we pose a two-fold challenge for the solution of the cosmological moduli problem. First, we show that the heavy moduli decay before they can begin to dominate the energy density of the Universe. Hence they are not able to dilute any unwanted relics. And second, we argue that, in order to obtain thermal inflation in the closed string moduli sector, one needs to go beyond the present EFT description.

  7. Multi-Material Decomposition using Low-Current X-Ray and a Photon-Counting CZT Detector

    PubMed Central

    Kim, Sangtaek; Hernandez, Andrew; Alhassen, Fares; Pivovaroff, Michael; Cho, Hyo-Min; Gould, Robert G.; Seo, Youngho

    2013-01-01

    We developed and evaluated an x-ray photon-counting imaging system using an energy-resolving cadmium zinc telluride (CZT) detector coupled with application specific integrated circuit (ASIC) readouts. This x-ray imaging system can be used to identify different materials inside the object. The CZT detector has a large active area (5×5 array of 25 CZT modules, each with 16×16 pixels, cover a total area of 200 mm × 200 mm), high stopping efficiency for x-ray photons (~ 100 % at 60 keV and 5 mm thickness). We explored the performance of this system by applying different energy windows around the absorption edges of target materials, silver and indium, in order to distinguish one material from another. The photon-counting CZT-based x-ray imaging system was able to distinguish between the materials, demonstrating its capability as a radiation-spectroscopic decomposition system. PMID:23503709

  8. Multi-Material Decomposition using Low-Current X-Ray and a Photon-Counting CZT Detector.

    PubMed

    Kim, Sangtaek; Hernandez, Andrew; Alhassen, Fares; Pivovaroff, Michael; Cho, Hyo-Min; Gould, Robert G; Seo, Youngho

    2011-01-01

    We developed and evaluated an x-ray photon-counting imaging system using an energy-resolving cadmium zinc telluride (CZT) detector coupled with application specific integrated circuit (ASIC) readouts. This x-ray imaging system can be used to identify different materials inside the object. The CZT detector has a large active area (5×5 array of 25 CZT modules, each with 16×16 pixels, cover a total area of 200 mm × 200 mm), high stopping efficiency for x-ray photons (~ 100 % at 60 keV and 5 mm thickness). We explored the performance of this system by applying different energy windows around the absorption edges of target materials, silver and indium, in order to distinguish one material from another. The photon-counting CZT-based x-ray imaging system was able to distinguish between the materials, demonstrating its capability as a radiation-spectroscopic decomposition system.

  9. SUSY's Ladder: reframing sequestering at Large Volume

    NASA Astrophysics Data System (ADS)

    Reece, Matthew; Xue, Wei

    2016-04-01

    Theories with approximate no-scale structure, such as the Large Volume Scenario, have a distinctive hierarchy of multiple mass scales in between TeV gaugino masses and the Planck scale, which we call SUSY's Ladder. This is a particular realization of Split Supersymmetry in which the same small parameter suppresses gaugino masses relative to scalar soft masses, scalar soft masses relative to the gravitino mass, and the UV cutoff or string scale relative to the Planck scale. This scenario has many phenomenologically interesting properties, and can avoid dangers including the gravitino problem, flavor problems, and the moduli-induced LSP problem that plague other supersymmetric theories. We study SUSY's Ladder using a superspace formalism that makes the mysterious cancelations in previous computations manifest. This opens the possibility of a consistent effective field theory understanding of the phenomenology of these scenarios, based on power-counting in the small ratio of string to Planck scales. We also show that four-dimensional theories with approximate no-scale structure enforced by a single volume modulus arise only from two special higher-dimensional theories: five-dimensional supergravity and ten-dimensional type IIB supergravity. This gives a phenomenological argument in favor of ten dimensional ultraviolet physics which is different from standard arguments based on the consistency of superstring theory.

  10. Small pixel CZT detector for hard X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C.

    2011-10-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20×20 pixels on a 250 μm pitch, with each pixel gold-stud bonded to an energy resolving circuit in the ASIC. The DAQ system digitised the ASIC output with 14 bit resolution, performing offset corrections and data storage to disc in real time at up to 40,000 frames per second. The detector geometry and ASIC design was optimised for X-ray spectroscopy up to 150 keV and made use of the small pixel effect to preferentially measure the electron signal. A 241Am source was used to measure the spectroscopic performance and uniformity of the detectors. The average energy resolution (FWHM at 59.54 keV) of each pixel ranged from 1.09±0.46 to 1.50±0.57 keV across the four detectors. The detectors showed good spectral performance and uniform response over almost all pixels in the 20×20 array. A large area 80×80 pixel detector will be built that will utilise the scalable design of the ASIC and the large areas of monolithic spectroscopic grade THM grown CZT that are now available. The large area detector will have the same performance as that demonstrated here.

  11. Large-volume sampling and preconcentration for trace explosives detection.

    SciTech Connect

    Linker, Kevin Lane

    2004-05-01

    A trace explosives detection system typically contains three subsystems: sample collection, preconcentration, and detection. Sample collection of trace explosives (vapor and particulate) through large volumes of airflow helps reduce sampling time while increasing the amount of dilute sample collected. Preconcentration of the collected sample before introduction into the detector improves the sensitivity of the detector because of the increase in sample concentration. By combining large-volume sample collection and preconcentration, an improvement in the detection of explosives is possible. Large-volume sampling and preconcentration is presented using a systems level approach. In addition, the engineering of large-volume sampling and preconcentration for the trace detection of explosives is explained.

  12. Large space systems technology, 1980, volume 1

    NASA Technical Reports Server (NTRS)

    Kopriver, F., III (Compiler)

    1981-01-01

    The technological and developmental efforts in support of the large space systems technology are described. Three major areas of interests are emphasized: (1) technology pertient to large antenna systems; (2) technology related to large space systems; and (3) activities that support both antenna and platform systems.

  13. The persistence of the large volumes in black holes

    NASA Astrophysics Data System (ADS)

    Ong, Yen Chin

    2015-08-01

    Classically, black holes admit maximal interior volumes that grow asymptotically linearly in time. We show that such volumes remain large when Hawking evaporation is taken into account. Even if a charged black hole approaches the extremal limit during this evolution, its volume continues to grow; although an exactly extremal black hole does not have a "large interior". We clarify this point and discuss the implications of our results to the information loss and firewall paradoxes.

  14. CZT nanoRAIDER_VFG Factsheet

    SciTech Connect

    James, R.; A. E. Bolotnikov; Cui, Yonggang

    2016-01-15

    Brookhaven National Laboratory (BNL) is working with FLIR System Inc., the manufacturer of the nanoRAIDER, to design a handheld device based on a position-sensitive virtual Frisch-grid (VFG) Cadmium-Zinc-Telluride (CdZnTe or CZT) detector array (with 1% or better energy resolution). The new device called nanoRAIDER VFG will be an improvement to the current nanoRAIDER, which is a compact gamma-ray detection instrument manufactured by FLIR Systems Inc. that employs relatively lower-performing CZT hemispheric detectors (i.e., 3%-FWHM CZT detectors). The nanoRAIDER will significantly improve the accuracy while maintaining similar efficiency, as compared to the nanoRAIDER, for in-field analysis of nuclear materials and detection of undeclared activities during inspections conducted by the International Atomic Energy Agency (IAEA). Since the nanoRAIDER is currently used by the IAEA as part of its Complementary Access toolkit, a relatively quick acceptance of the nanoRAIDER VFG for safeguards is anticipated. The nanoRAIDER VFG will help address several items listed in the IAEA’s Long-Term R&D Plan that could enhance the abilities to detect undeclared nuclear material and activities.

  15. Large mode-volume, large beta, photonic crystal laser resonator

    SciTech Connect

    Dezfouli, Mohsen Kamandar; Dignam, Marc M.

    2014-12-15

    We propose an optical resonator formed from the coupling of 13, L2 defects in a triangular-lattice photonic crystal slab. Using a tight-binding formalism, we optimized the coupled-defect cavity design to obtain a resonator with predicted single-mode operation, a mode volume five times that of an L2-cavity mode and a beta factor of 0.39. The results are confirmed using finite-difference time domain simulations. This resonator is very promising for use as a single mode photonic crystal vertical-cavity surface-emitting laser with high saturation output power compared to a laser consisting of one of the single-defect cavities.

  16. Technologies for imaging neural activity in large volumes

    PubMed Central

    Ji, Na; Freeman, Jeremy; Smith, Spencer L.

    2017-01-01

    Neural circuitry has evolved to form distributed networks that act dynamically across large volumes. Collecting data from individual planes, conventional microscopy cannot sample circuitry across large volumes at the temporal resolution relevant to neural circuit function and behaviors. Here, we review emerging technologies for rapid volume imaging of neural circuitry. We focus on two critical challenges: the inertia of optical systems, which limits image speed, and aberrations, which restrict the image volume. Optical sampling time must be long enough to ensure high-fidelity measurements, but optimized sampling strategies and point spread function engineering can facilitate rapid volume imaging of neural activity within this constraint. We also discuss new computational strategies for the processing and analysis of volume imaging data of increasing size and complexity. Together, optical and computational advances are providing a broader view of neural circuit dynamics, and help elucidate how brain regions work in concert to support behavior. PMID:27571194

  17. Novel Method for Growing Te-Inclusion-Free CZT

    SciTech Connect

    Bolotnikov,A.

    2008-06-17

    The authors propose a new method for growth of detector-grade CdZnTe (CZT) with reduced concentration and sizes of Te inclusions. The method is designed to impede the formation of Te-rich inclusions in crystals due to the use of new CZT growth method and a unique ampoule design.

  18. Line profile modelling for multi-pixel CZT detectors

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, T.; Vadawale, S. V.; Rao, A. R.; Bhattacharya, D.; Mithun, N. P. S.; Bhalerao, V.

    2016-07-01

    Cadmium Zinc Telluride (CZT) detectors have been the mainstay for hard X-ray astronomy for its high quantum efficiency, fine energy resolution, near room temperature operation, and radiation hardness. In order to fully utilize the spectroscopic capabilities of CZT detectors, it is important to generate accurate response matrix, which in turn requires precise modelling of the line profiles for the CZT detectors. We have developed a numerical model taking into account the mobility and lifetime of the charge carriers and intrpixel charge sharing for the CZT detectors. This paper describes the details of the modelling along with the experimental measurements of mobility, lifetime and charge sharing fractions for the CZT detector modules of thickness of 5 mm and 2.5 mm pixel size procured from Orbotech Medical Solutions (same modules used in AstroSat-CZTI).

  19. Sparticle spectra from Large-Volume String Compactifications

    SciTech Connect

    Conlon, Joseph P.

    2007-11-20

    Large-volume models are a promising approach to stabilising moduli and generating the weak hierarchy through TeV-supersymmetry. I describe the pattern of sparticle mass spectra that arises in these models.

  20. Coherent motility measurements of biological objects in a large volume

    NASA Astrophysics Data System (ADS)

    Ebersberger, J.; Weigelt, G.; Li, Yajun

    1986-05-01

    We have performed space-time intensity cross-correlation measurements of boiling image plane speckle interferograms to investigate the motility of a large number of small biological objects. Experiments were carried out with Artemia Salina species at various water temperatures. The advantage of this method is the fact that many objects in a large volume can be measured simultaneously.

  1. EFFECTS OF MATERIAL IMPROVEMENT ON CZT DETECTORS.

    SciTech Connect

    CHU, M.; CARINI, G.A.; ET AL.

    2006-08-13

    CZT material quality improvement has been achieved by optimizing the crystal growth process. N-type conductivity has been measured on as-grown, undoped, Cd{sub 0.9}Zn{sub 0.1}Te. Cd{sub 0.85}Zn{sub 0.15}Te crystals have been grown. for producing high resistivity CZT radiation detectors. The best FWHM of {sup 57}Co 122KeV spectrum was measured to be 3.7% and ({mu}{tau}){sub e} was 3 x 10{sup -3} cm{sup 2}V{sup -1}. The microscopic gamma ray response using a beam size of 10 {micro}m has been used to map the entire 4 mm x 4 mm detector. Several black spots indicating no signal responses were observed while all other areas showed an average of 65-70% collection efficiency. The black spots suggest that at those locations, the Te precipitates are larger than 10 {micro}m. Detailed microscopic infrared transmission measurement on the sample found that most Te precipitates have sizes of 4-6 {micro}m. Theoretical analysis of the results suggests that singly and doubly ionized Te{sub Cd}V{sub Cd}{sup 2} might be the shallow and deep donors previously assigned to Te{sub Cd} by us.

  2. Large-Volume High-Pressure Mineral Physics in Japan

    NASA Astrophysics Data System (ADS)

    Liebermann, Robert C.; Prewitt, Charles T.; Weidner, Donald J.

    American high-pressure research with large sample volumes developed rapidly in the 1950s during the race to produce synthetic diamonds. At that time the piston cylinder, girdle (or belt), and tetrahedral anvil devices were invented. However, this development essentially stopped in the late 1950s, and while the diamond anvil cell has been used extensively in the United States with spectacular success for high-pressure experiments in small sample volumes, most of the significant technological advances in large-volume devices have taken place in Japan. Over the past 25 years, these technical advances have enabled a fourfold increase in pressure, with many important investigations of the chemical and physical properties of materials synthesized at high temperatures and pressures that cannot be duplicated with any apparatus currently available in the United States.

  3. Annual Report: Property Improvement in CZT via Modeling and Processing Innovations

    SciTech Connect

    Henager, Charles H.; Setyawan, Wahyu; Gao, Fei; Hu, Shenyang Y.; Bliss, Mary; Riley, Brian J.; Alvine, Kyle J.; Stave, Jean A.

    2013-09-01

    The objective of this project is to develop growth models of CZT crystals from the melt using vertical gradient freeze (VGF) or vertical Bridgman growth as a typical process. Further, the project will perform critical experiments including single crystal growth to validate the growth models and to provide detailed data for modeling and simulation. Ideally, the project will develop growth models that will provide, for the first time, choices for optimal CZT single crystal growth from the melt based on model input. The overarching goal that guides this research proposal is to produce large, single crystals of CZT with good yield and reproducible properties. In our view this depends on 1) understanding crystal growth processes, including annealing and cool-down processing, and 2) understanding the role of defects on detector response since it is not possible, yet, to produce defect-free materials. Models of defect structure and formation are addressed. Validated models and experiments on reducing defects in melt-grown crystals are used to guide our understanding of growth processes and in-furnace annealing plus cool-down.

  4. CZT Detector Development for Hard X-ray Astronomy

    NASA Astrophysics Data System (ADS)

    Garson, Alfred, III; Li, Q.; Beilicke, M.; Bose, R.; Burger, A.; Dowkonnt, P.; Groza, M.; Simburger, G.; Krawczynski, H.

    2008-05-01

    Cadmium Zinc Telluride (CZT) has proven itself as an excellent material for detection of hard X-rays. Advances in crystal growth have increased the quality and size of available single CZT crystals. We report on our ongoing development and characterization of CZT detector systems. With our dedicated class-100 cleanroom, we fabricate detectors using CZT crystals from different manufactures. Using photolithography and e-beam evaporation, we can produce detectors with different contact designs (pixellated, strip, monolithic, steering grid), contact dimensions (down to 50 microns), and contact materials (In, Ti, Au, etc.) . In addition, we develop ASIC readouts for various CZT detector applications, including our characterization of the detectors. We measure I-V and C-V curves for the detectors as well as their spectroscopic performance. We compare measured results with those from detailed modelling and simulations. The CZT detector systems can then be optimized for applications such as X-ray imaging and polarimetry with satellite or balloon-borne instruments.

  5. CZT Detector Development for Hard X-ray Astronomy

    NASA Astrophysics Data System (ADS)

    Garson, A. B., III; Li, Q.; Beilicke, M.; Bose, R.; Burger, A.; Dowkonnt, P.; Groza, M.; Simburger, G.; Krawczynski, H.

    2008-04-01

    Cadmium Zinc Telluride (CZT) has proven itself as an excellent material for detection of hard X-rays. Advances in crystal growth have increased the quality and size of available single CZT crystals. We report on our ongoing development and characterization of CZT detector systems. With our dedicated class-100 cleanroom, we fabricate detectors using CZT crystals from different manufactures. Using photolithography and e-beam evaporation, we can produce detectors with different contact designs (pixellated, strip, monolithic, steering grid), contact dimensions (down to 50 microns), and contact materials (In, Ti, Au, etc.) . In addition, we develop ASIC readouts for various CZT detector applications, including our characterization of the detectors. We measure I-V and C-V curves for the detectors as well as their spectroscopic performance. We compare measured results with those from detailed modelling and simulations. The CZT detector systems can then be optimized for applications such as X-ray imaging and polarimetry with satellite or balloon-borne instruments.

  6. Large discharge-volume, silent discharge spark plug

    DOEpatents

    Kang, Michael

    1995-01-01

    A large discharge-volume spark plug for providing self-limiting microdischarges. The apparatus includes a generally spark plug-shaped arrangement of a pair of electrodes, where either of the two coaxial electrodes is substantially shielded by a dielectric barrier from a direct discharge from the other electrode, the unshielded electrode and the dielectric barrier forming an annular volume in which self-terminating microdischarges occur when alternating high voltage is applied to the center electrode. The large area over which the discharges occur, and the large number of possible discharges within the period of an engine cycle, make the present silent discharge plasma spark plug suitable for use as an ignition source for engines. In the situation, where a single discharge is effective in causing ignition of the combustible gases, a conventional single-polarity, single-pulse, spark plug voltage supply may be used.

  7. Cadium-Zinc-Telluride (CZT) Gamma Ray Spectrometry

    SciTech Connect

    William Quam

    2001-09-01

    This report describes CZT crystals and their use in large arrays for generation of gamma ray spectra. Laboratory spectra will be shown together with spectra accumulated by various battery powered portable instruments (see Appendix A). One of these portable instruments was specifically constructed to minimize power consumption and yet provide reasonable isotope identification capability. Detailed data will be presented covering gamma energy resolution, gamma peak shapes, system background, and detector efficiency. Nearly all data were taken with very small crystals of CZT; cubes 5 mm on a side. A few spectra will be presented from cylindrical crystals of about the same size (see Appendix A). The small crystal size leads to low counting rates and extended counting times for reliable isotope identification. We have addressed this problem by using arrays of CZT crystals, initially two crystals and, at present, arrays of eight crystals. Data will be shown relating spectral parameters for these two arrays. System MDA is one way of combining resolution, efficiency, and background that will enable direct comparison of various detector types for individual isotope identification. We have calculated the MDA for an early dual crystal array and the current eight crystal array. Data derived from each array will be presented. In addition, it is possible to extrapolate the MDA methodology to much larger arrays. A 32-crystal array is under construction and extrapolations to 256 and 1024 crystals are considered possible. Estimated MDA values for these larger arrays are also presented. Several 8-crystal arrays have been constructed and versions have been incorporated into portable instruments. Descriptions of these small instruments are given covering physical size, weight, and general configuration. These instruments have been tested for shock and temperature effects and data will be presented on the results of these tests. The MDA concept will also allow extrapolation to large

  8. Large volume leukapheresis: Efficacy and safety of processing patient's total blood volume six times.

    PubMed

    Bojanic, Ines; Dubravcic, Klara; Batinic, Drago; Cepulic, Branka Golubic; Mazic, Sanja; Hren, Darko; Nemet, Damir; Labar, Boris

    2011-04-01

    Large-volume leukapheresis (LVL) differs from standard leukapheresis by increased blood flow and an altered anticoagulation regimen. An open issue is to what degree a further increase in processed blood volume is reasonable in terms of higher yields and safety. In 30 LVL performed in patients with hematologic malignancies, 6 total blood volumes were processed. LVL resulted in a higher CD34+ cell yield without a change in graft quality. Although a marked platelet decrease can be expected, LVL is safe and can be recommended as the standard procedure for patients who mobilize low numbers of CD34+ cells and when high number of CD34+ cells are required.

  9. Concentration of Enteroviruses from Large Volumes of Water

    PubMed Central

    Sobsey, Mark D.; Wallis, Craig; Henderson, Marilyn; Melnick, Joseph L.

    1973-01-01

    An improved method for concentrating viruses from large volumes of clean waters is described. It was found that, by acidification, viruses in large volumes of water could be efficiently adsorbed to epoxy-fiber-glass and nitrocellulose filters in the absence of exogenously added salts. Based upon this finding, a modified version of our previously described virus concentration system was developed for virus monitoring of clean waters. In this procedure the water being tested is acidified by injection of N HCl prior to passage through a virus adsorber consisting of a fiber-glass cartridge depth filter and an epoxy-fiber-glass membrane filter in series. The adsorbed viruses are then eluted with a 1-liter volume of pH 11.5 eluent and reconcentrated by adsorption to and elution from a small epoxy-fiber-glass filter series. With this method small quantities of poliovirus in 100-gallon (378.5-liter) volumes of tapwater were concentrated nearly 40,000-fold with an average virus recovery efficiency of 77%. Images PMID:16349972

  10. Large volume multiple-path nuclear pumped laser

    NASA Technical Reports Server (NTRS)

    Hohl, F.; Deyoung, R. J. (Inventor)

    1981-01-01

    Large volumes of gas are excited by using internal high reflectance mirrors that are arranged so that the optical path crosses back and forth through the excited gaseous medium. By adjusting the external dielectric mirrors of the laser, the number of paths through the laser cavity can be varied. Output powers were obtained that are substantially higher than the output powers of previous nuclear laser systems.

  11. Improving the spatial resolution in CZT detectors using charge sharing effect and transient signal analysis: Simulation study

    NASA Astrophysics Data System (ADS)

    Zheng, Xiaoqing; Cheng, Zeng; Deen, M. Jamal; Peng, Hao

    2016-02-01

    Cadmium Zinc Telluride (CZT) semiconductor detectors are capable of providing superior energy resolution and three-dimensional position information of gamma ray interactions in a large variety of fields, including nuclear physics, gamma-ray imaging and nuclear medicine. Some dedicated Positron Emission Tomography (PET) systems, for example, for breast cancer detection, require higher contrast recovery and more accurate event location compared with a whole-body PET system. The spatial resolution is currently limited by electrode pitch in CZT detectors. A straightforward approach to increase the spatial resolution is by decreasing the detector electrode pitch, but this leads to higher fabrication cost and a larger number of readout channels. In addition, inter-electrode charge spreading can negate any improvement in spatial resolution. In this work, we studied the feasibility of achieving sub-pitch spatial resolution in CZT detectors using two methods: charge sharing effect and transient signal analysis. We noted that their valid ranges of usage were complementary. The dependences of their corresponding valid ranges on electrode design, depth-of-interaction (DOI), voltage bias and signal triggering threshold were investigated. The implementation of these two methods in both pixelated and cross-strip configuration of CZT detectors were discussed. Our results show that the valid range of charge sharing effect increases as a function of DOI, but decreases with increasing gap width and bias voltage. For a CZT detector of 5 mm thickness, 100 μm gap and biased at 400 V, the valid range of charge sharing effect was found to be about 112.3 μm around the gap center. This result complements the valid range of the transient signal analysis within one electrode pitch. For a signal-to-noise ratio (SNR) of 17 and preliminary measurements, the sub-pitch spatial resolution is expected to be 30 μm and 250 μm for the charge sharing and transient signal analysis methods

  12. Parallel Rendering of Large Time-Varying Volume Data

    NASA Technical Reports Server (NTRS)

    Garbutt, Alexander E.

    2005-01-01

    Interactive visualization of large time-varying 3D volume datasets has been and still is a great challenge to the modem computational world. It stretches the limits of the memory capacity, the disk space, the network bandwidth and the CPU speed of a conventional computer. In this SURF project, we propose to develop a parallel volume rendering program on SGI's Prism, a cluster computer equipped with state-of-the-art graphic hardware. The proposed program combines both parallel computing and hardware rendering in order to achieve an interactive rendering rate. We use 3D texture mapping and a hardware shader to implement 3D volume rendering on each workstation. We use SGI's VisServer to enable remote rendering using Prism's graphic hardware. And last, we will integrate this new program with ParVox, a parallel distributed visualization system developed at JPL. At the end of the project, we Will demonstrate remote interactive visualization using this new hardware volume renderer on JPL's Prism System using a time-varying dataset from selected JPL applications.

  13. ProtoEXIST2: Advanced Wide-field Imaging CZT Detector Development For The HET On The Proposed EXIST Mission

    NASA Astrophysics Data System (ADS)

    Hong, JaeSub; Allen, B.; Grindlay, J.; Barthelmy, S.; Baker, R.; Gehrels, N.; Cook, W.; Kaye, S.; Harrison, F.

    2010-03-01

    We describe our development of ProtoEXIST2, the advanced CZT imaging detector and wide field telescope prototype for the High Energy Telescope (HET) on the proposed Energetic X-ray Imaging Survey Telescope (EXIST) mission. EXIST is a multi-wavelength Medium class mission which would explore the early Universe using high redshift Gamma-ray Bursts and survey black holes on all scales. ProtoEXIST2 will demonstrate the feasibility of a large scale imaging module (256 cm2) with a close-tiled array of fine pixel (0.6 mm) CZT with a balloon flight test in 2010 or 2011. This second generation close-tiled CZT imager follows ProtoEXIST1, which had a recent successful balloon flight (see Allen et al in this meeting) using the same area CZT detector module (256 cm2) but with larger pixel size (2.5mm). For signal readout and event processing, we use the Direct-Bond (DB) ASIC, developed for the NuSTAR mission to be used in a close-tiled 2 x 2 array of 2x2 cm2 CZT detectors, each with 32x32 pixels. The DB-ASIC is attractive for a large scale implementation of tiled imaging CZT detectors given its low noise and power consumption (70uW/pixel). We are developing readout for the DB-ASIC that incorporates our back-end FPGA readout architecture developed for ProtoEXIST1 in order to accomplish the 256 cm2 detector module area with totally vertical integration (i.e. no auxialliary boards to the sides of the module. This is required to tile large numbers of modules into the very large total area (4.5m^2) proposed for the HET on EXIST. We review the design of the EXIST/HET and its optimum shielding in light of our ProtoEXIST1 balloon flight and our plan for future development of ProtoEXIST3, a final EXIST/HET detector module that would incorporate a still lower power version of the DB ASIC.

  14. Geometric Measures of Large Biomolecules: Surface, Volume and Pockets

    PubMed Central

    Mach, Paul; Koehl, Patrice

    2011-01-01

    Geometry plays a major role in our attempt to understand the activity of large molecules. For example, surface area and volume are used to quantify the interactions between these molecules and the water surrounding them in implicit solvent models. In addition, the detection of pockets serves as a starting point for predictive studies of biomolecule-ligand interactions. The alpha shape theory provides an exact and robust method for computing these geometric measures. Several implementations of this theory are currently available. We show however that these implementations fail on very large macromolecular systems. We show that these difficulties are not theoretical; rather, they are related to the architecture of current computers that rely on the use of cache memory to speed up calculation. By rewriting the algorithms that implement the different steps of the alpha shape theory such that we enforce locality, we show that we can remediate these cache problems; the corresponding code, UnionBall has an apparent (n) behavior over a large range of values of n (up to tens of millions), where n is the number of atoms. As an example, it takes 136 seconds with UnionBall to compute the contribution of each atom to the surface area and volume of a viral capsid with more than five million atoms on a commodity PC. UnionBall includes functions for computing the surface area and volume of the intersection of two, three and four spheres that are fully detailed in an appendix. UnionBall is available as an OpenSource software. PMID:21823134

  15. Electrolyte and plasma enzyme analyses during large-volume liposuction.

    PubMed

    Lipschitz, Avron H; Kenkel, Jeffrey M; Luby, Maureen; Sorokin, Evan; Rohrich, Rod J; Brown, Spencer A

    2004-09-01

    Substantial fluid shifts occur during liposuction as wetting solution is infiltrated subcutaneously and fat is evacuated, causing potential electrolyte imbalances. In the porcine model for large-volume liposuction, plasma aspartate aminotransferase and alanine transaminase levels were elevated following liposuction. These results raised concerns for possible mechanical injury and/or lidocaine-induced hepatocellular toxicity in a clinical setting. The first objective of this human model study was to explore the effect of the liposuction procedure on electrolyte balance. The second objective was to determine whether elevated plasma aminotransferase levels were observed subsequent to large-volume liposuction. Five female volunteers underwent three-stage, ultrasound-assisted liposuction. Blood samples were collected perioperatively. Plasma levels of sodium, potassium, venous carbon dioxide, blood urea nitrogen, chloride, and creatinine were determined. Liver function analyte levels were measured, including albumin, total protein, aspartate aminotransferase, and alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, and total bilirubin. To further define intracellular enzyme release, creatine kinase levels were measured. Mild hyponatremia was evident postoperatively (134 to 136 mmol/liter) in four patients. Hypokalemia was evident intraoperatively in all subjects (mean +/- SEM; 3.3 +/- 0.16 mmol/liter; range, 3.0 to 3.4 mmol/liter). Hypoalbuminemia and hypoproteinemia were observed throughout the study (baseline: 2.9 +/- 0.2 g/dl; range, 2.6 to 3.5 g/dl), decreasing to 10 to 40 percent 24 hours postoperatively (2.0 +/- 0.2 g/dl; range, 1.7 to 2.1 g/dl). Aspartate aminotransferase, alanine transaminase, and creatine kinase levels were significantly elevated after the procedure (190 +/- 47.1 U/liter, 50 +/- 7.7 U/liter, and 11,219 +/- 2556.7 U/liter, respectively) (p < 0.01). Release of antidiuretic hormone and even mildly hypotonic intravenous fluid

  16. Volumetric leak detection in large underground storage tanks. Volume 1

    SciTech Connect

    Starr, J.W.; Wise, R.F.; Maresca, J.W.

    1991-08-01

    A set of experiments was conducted to determine whether volumetric leak detection system presently used to test underground storage tanks (USTs) up to 38,000 L (10,000 gal) in capacity could meet EPA's regulatory standards for tank tightness and automatic tank gauging systems when used to test tanks up to 190,000 L (50,000 gal) in capacity. The experiments, conducted on two partially filled 190,000-L (50,000-gal) USTs at Griffiss Air Force Base in upstate New York during late August 1990, showed that a system's performance in large tanks depends primarily on the accuracy of the temperature compensation, which is inversely proportional to the volume of product in the tank. Errors in temperature compensation that were negligible in tests in small tanks were important in large tanks. The experiments further suggest that a multiple-test strategy is also required.

  17. Ultra-rapid formation of large volumes of evolved magma

    NASA Astrophysics Data System (ADS)

    Michaut, C.; Jaupart, C.

    2006-10-01

    We discuss evidence for, and evaluate the consequences of, the growth of magma reservoirs by small increments of thin (⋍ 1-2 m) sills. For such thin units, cooling proceeds faster than the nucleation and growth of crystals, which only allows a small amount of crystallization and leads to the formation of large quantities of glass. The heat balance equation for kinetic-controlled crystallization is solved numerically for a range of sill thicknesses, magma injection rates and crustal emplacement depths. Successive injections lead to the accumulation of poorly crystallized chilled magma with the properties of a solid. Temperatures increase gradually with each injection until they become large enough to allow a late phase of crystal nucleation and growth. Crystallization and latent heat release work in a positive feedback loop, leading to catastrophic heating of the magma pile, typically by 200 °C in a few decades. Large volumes of evolved melt are made available in a short time. The time for the catastrophic heating event varies as Q- 2 , where Q is the average magma injection rate, and takes values in a range of 10 5-10 6 yr for typical geological magma production rates. With this mechanism, storage of large quantities of magma beneath an active volcanic center may escape detection by seismic methods.

  18. SUSY’s Ladder: Reframing sequestering at Large Volume

    DOE PAGES

    Reece, Matthew; Xue, Wei

    2016-04-07

    Theories with approximate no-scale structure, such as the Large Volume Scenario, have a distinctive hierarchy of multiple mass scales in between TeV gaugino masses and the Planck scale, which we call SUSY's Ladder. This is a particular realization of Split Supersymmetry in which the same small parameter suppresses gaugino masses relative to scalar soft masses, scalar soft masses relative to the gravitino mass, and the UV cutoff or string scale relative to the Planck scale. This scenario has many phenomenologically interesting properties, and can avoid dangers including the gravitino problem, flavor problems, and the moduli-induced LSP problem that plague othermore » supersymmetric theories. We study SUSY's Ladder using a superspace formalism that makes the mysterious cancelations in previous computations manifest. This opens the possibility of a consistent effective field theory understanding of the phenomenology of these scenarios, based on power-counting in the small ratio of string to Planck scales. We also show that four-dimensional theories with approximate no-scale structure enforced by a single volume modulus arise only from two special higher-dimensional theories: five-dimensional supergravity and ten-dimensional type IIB supergravity. As a result, this gives a phenomenological argument in favor of ten dimensional ultraviolet physics which is different from standard arguments based on the consistency of superstring theory.« less

  19. SUSY’s Ladder: Reframing sequestering at Large Volume

    SciTech Connect

    Reece, Matthew; Xue, Wei

    2016-04-07

    Theories with approximate no-scale structure, such as the Large Volume Scenario, have a distinctive hierarchy of multiple mass scales in between TeV gaugino masses and the Planck scale, which we call SUSY's Ladder. This is a particular realization of Split Supersymmetry in which the same small parameter suppresses gaugino masses relative to scalar soft masses, scalar soft masses relative to the gravitino mass, and the UV cutoff or string scale relative to the Planck scale. This scenario has many phenomenologically interesting properties, and can avoid dangers including the gravitino problem, flavor problems, and the moduli-induced LSP problem that plague other supersymmetric theories. We study SUSY's Ladder using a superspace formalism that makes the mysterious cancelations in previous computations manifest. This opens the possibility of a consistent effective field theory understanding of the phenomenology of these scenarios, based on power-counting in the small ratio of string to Planck scales. We also show that four-dimensional theories with approximate no-scale structure enforced by a single volume modulus arise only from two special higher-dimensional theories: five-dimensional supergravity and ten-dimensional type IIB supergravity. As a result, this gives a phenomenological argument in favor of ten dimensional ultraviolet physics which is different from standard arguments based on the consistency of superstring theory.

  20. Characterization of secondary phases in modified vertical bridgman growth czt

    SciTech Connect

    Duff, Martine

    2009-07-10

    CdZnTe or 'CZT' crystals are highly suitable for use as a room temperature based spectrometer for the detection and characterization of gamma radiation. Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. For example, various structural heterogeneities within the CZT crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary phases (SP) can have a negative impact on the detector performance. In this study, a CZT material was grown by the modified vertical Bridgman growth (MVB) method with zone leveled growth without excess Te in the melt. Visual observations of material from the growth of this material revealed significant voids and SP. Three samples from this material was analyzed using various analytical techniques to evaluate its electrical properties, purity and detector performance as radiation spectrometers and to determine the morphology, dimension and elemental/structural composition of one of the SP in this material. This material was found to have a high resistivity but poor radiation spectrometer performance. It had SP that were rich in polycrystalline aluminum oxide (Al{sub 2}O{sub 3}), metallic Te and polycrystalline CdZnTe and 15 to 50 {micro}m in diameter. Bulk elemental analyses of sister material from elsewhere in the boule did not contain high levels of Al so there is considerable elemental impurity heterogeneity within the boule from this growth.

  1. Large volume water sprays for dispersing warm fogs

    NASA Astrophysics Data System (ADS)

    Keller, V. W.; Anderson, B. J.; Burns, R. A.; Lala, G. G.; Meyer, M. B.

    A new method for dispersing of warm fogs which impede visibility and alter schedules is described. The method uses large volume recycled water sprays to create curtains of falling drops through which the fog is processed by the ambient wind and spray-induced air flow; the fog droplets are removed by coalescence/rainout. The efficiency of this fog droplet removal process depends on the size spectra of the spray drops and optimum spray drop size is calculated as between 0.3-1.0 mm in diameter. Water spray tests were conducted in order to determine the drop size spectra and temperature response of sprays produced by commercially available fire-fighting nozzles, and nozzle array tests were utilized to study air flow patterns and the thermal properties of the overall system. The initial test data reveal that the fog-dispersal procedure is effective.

  2. High density three-dimensional localization microscopy across large volumes

    PubMed Central

    Legant, Wesley R.; Shao, Lin; Grimm, Jonathan B.; Brown, Timothy A.; Milkie, Daniel E.; Avants, Brian B.; Lavis, Luke D.; Betzig, Eric

    2016-01-01

    Extending three-dimensional (3D) single molecule localization microscopy away from the coverslip and into thicker specimens will greatly broaden its biological utility. However, localizing molecules in 3D with high precision in such samples, while simultaneously achieving the extreme labeling densities required for high resolution of densely crowded structures is challenging due to the limitations both of conventional imaging modalities and of conventional labeling techniques. Here, we combine lattice light sheet microscopy with newly developed, freely diffusing, cell permeable chemical probes with targeted affinity towards either DNA, intracellular membranes, or the plasma membrane. We use this combination to perform high localization precision, ultra-high labeling density, multicolor localization microscopy in samples up to 20 microns thick, including dividing cells and the neuromast organ of a zebrafish embryo. We also demonstrate super-resolution correlative imaging with protein specific photoactivable fluorophores, providing a mutually compatible, single platform alternative to correlative light-electron microscopy over large volumes. PMID:26950745

  3. Large space telescope, phase A. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Phase A study of the Large Space Telescope (LST) is reported. The study defines an LST concept based on the broad mission guidelines provided by the Office of Space Science (OSS), the scientific requirements developed by OSS with the scientific community, and an understanding of long range NASA planning current at the time the study was performed. The LST is an unmanned astronomical observatory facility, consisting of an optical telescope assembly (OTA), scientific instrument package (SIP), and a support systems module (SSM). The report consists of five volumes. The report describes the constraints and trade off analyses that were performed to arrive at a reference design for each system and for the overall LST configuration. A low cost design approach was followed in the Phase A study. This resulted in the use of standard spacecraft hardware, the provision for maintenance at the black box level, growth potential in systems designs, and the sharing of shuttle maintenance flights with other payloads.

  4. Multisystem organ failure after large volume injection of castor oil.

    PubMed

    Smith, Silas W; Graber, Nathan M; Johnson, Rudolph C; Barr, John R; Hoffman, Robert S; Nelson, Lewis S

    2009-01-01

    We report a case of multisystem organ failure after large volume subcutaneous injection of castor oil for cosmetic enhancement. An unlicensed practitioner injected 500 mL of castor oil bilaterally to the hips and buttocks of a 28-year-old male to female transsexual. Immediate local pain and erythema were followed by abdominal and chest pain, emesis, headache, hematuria, jaundice, and tinnitus. She presented to an emergency department 12 hours postinjection. Persistently hemolyzed blood samples complicated preliminary laboratory analysis. She rapidly deteriorated despite treatment and developed fever, tachycardia, hemolysis, thrombocytopenia, hepatitis, respiratory distress, and anuric renal failure. An infectious diseases evaluation was negative. After intensive supportive care, including mechanical ventilation and hemodialysis, she was discharged 11 days later, requiring dialysis for an additional 1.5 months. Castor oil absorption was inferred from recovery of the Ricinus communis biomarker, ricinine, in the patient's urine (41 ng/mL). Clinicians should anticipate multiple complications after unapproved methods of cosmetic enhancement.

  5. Striped Bass, morone saxatilis, egg incubation in large volume jars

    USGS Publications Warehouse

    Harper, C.J.; Wrege, B.M.; Jeffery, Isely J.

    2010-01-01

    The standard McDonald jar was compared with a large volume jar for striped bass, Morone saxatilis, egg incubation. The McDonald jar measured 16 cm in diameter by 45 cm in height and had a volume of 6 L. The experimental jar measured 0.4 m in diameter by 1.3 m in height and had a volume of 200 L. The hypothesis is that there is no difference in percent survival of fry hatched in experimental jars compared with McDonald jars. Striped bass brood fish were collected from the Coosa River and spawned using the dry spawn method of fertilization. Four McDonald jars were stocked with approximately 150 g of eggs each. Post-hatch survival was estimated at 48, 96, and 144 h. Stocking rates resulted in an average egg loading rate (??1 SE) in McDonald jars of 21.9 ?? 0.03 eggs/mL and in experimental jars of 10.9 ?? 0.57 eggs/mL. The major finding of this study was that average fry survival was 37.3 ?? 4.49% for McDonald jars and 34.2 ?? 3.80% for experimental jars. Although survival in experimental jars was slightly less than in McDonald jars, the effect of container volume on survival to 48 h (F = 6.57; df = 1,5; P > 0.05), 96 h (F = 0.02; df = 1, 4; P > 0.89), and 144 h (F = 3.50; df = 1, 4; P > 0.13) was not statistically significant. Mean survival between replicates ranged from 14.7 to 60.1% in McDonald jars and from 10.1 to 54.4% in experimental jars. No effect of initial stocking rate on survival (t = 0.06; df = 10; P > 0.95) was detected. Experimental jars allowed for incubation of a greater number of eggs in less than half the floor space of McDonald jars. As hatchery production is often limited by space or water supply, experimental jars offer an alternative to extending spawning activities, thereby reducing labor and operations cost. As survival was similar to McDonald jars, the experimental jar is suitable for striped bass egg incubation. ?? Copyright by the World Aquaculture Society 2010.

  6. Background measurements from balloon-born imaging CZT detectors

    NASA Astrophysics Data System (ADS)

    Jenkins, Jonathan A.; Narita, Tomohiko; Grindlay, Jonathan E.; Bloser, Peter F.; Stahle, Carl M.; Parker, Bradford H.; Barthelmy, Scott D.

    2003-03-01

    We report detector characteristics and background measurements from two prototype imaging CdZnTe (CZT) detectors flown on a scientific balloon payload in May 2001. The detectors are both platinum-contact 10 mm × 10 mm × 5 mm CZT crystals, each with a 4 × 4 array of pixels tiling the anode. One is made from IMARAD horizontal Bridgman CZT, the other from eV Products high-pressure Bridgman CZT. Both detectors were mounted side-by-side in a flip-chip configuration and read out by a 32-channel IDE VA/TA ASIC preamp/shaper. We enclosed the detectors in the same 40o field-of-view collimator used in our previously-reported September 2000 flight. I-V curves for the detectors are diode-like, and we find that the platinum contacts adhere significantly better to the CZT surfaces than gold to previosu detectors. The detectors and instrumentation performed well in a 20-hour balloon flight on 23/24 May 2001. Although we discovered a significant instrumental background component in flight, it was possible to measure and subtract this component from the spectra. The resulting IMARAD detector background spectrum reaches ~5×10-3 counts cm-2s-1keV-1 at 100 keV and has a power-law index of ~2 at hgih energies. The eV Products detector has a similar spectrum, although there is more uncertainty in the enregy scale because of calibration complications.

  7. Volume visualization of multiple alignment of large genomicDNA

    SciTech Connect

    Shah, Nameeta; Dillard, Scott E.; Weber, Gunther H.; Hamann, Bernd

    2005-07-25

    Genomes of hundreds of species have been sequenced to date, and many more are being sequenced. As more and more sequence data sets become available, and as the challenge of comparing these massive ''billion basepair DNA sequences'' becomes substantial, so does the need for more powerful tools supporting the exploration of these data sets. Similarity score data used to compare aligned DNA sequences is inherently one-dimensional. One-dimensional (1D) representations of these data sets do not effectively utilize screen real estate. As a result, tools using 1D representations are incapable of providing informatory overview for extremely large data sets. We present a technique to arrange 1D data in 3D space to allow us to apply state-of-the-art interactive volume visualization techniques for data exploration. We demonstrate our technique using multi-millions-basepair-long aligned DNA sequence data and compare it with traditional 1D line plots. The results show that our technique is superior in providing an overview of entire data sets. Our technique, coupled with 1D line plots, results in effective multi-resolution visualization of very large aligned sequence data sets.

  8. Testing large volume water treatment and crude oil ...

    EPA Pesticide Factsheets

    Report EPA’s Homeland Security Research Program (HSRP) partnered with the Idaho National Laboratory (INL) to build the Water Security Test Bed (WSTB) at the INL test site outside of Idaho Falls, Idaho. The WSTB was built using an 8-inch (20 cm) diameter cement-mortar lined drinking water pipe that was previously taken out of service. The pipe was exhumed from the INL grounds and oriented in the shape of a small drinking water distribution system. Effluent from the pipe is captured in a lagoon. The WSTB can support drinking water distribution system research on a variety of drinking water treatment topics including biofilms, water quality, sensors, and homeland security related contaminants. Because the WSTB is constructed of real drinking water distribution system pipes, research can be conducted under conditions similar to those in a real drinking water system. In 2014, WSTB pipe was experimentally contaminated with Bacillus globigii spores, a non-pathogenic surrogate for the pathogenic B. anthracis, and then decontaminated using chlorine dioxide. In 2015, the WSTB was used to perform the following experiments: • Four mobile disinfection technologies were tested for their ability to disinfect large volumes of biologically contaminated “dirty” water from the WSTB. B. globigii spores acted as the biological contaminant. The four technologies evaluated included: (1) Hayward Saline C™ 6.0 Chlorination System, (2) Advanced Oxidation Process (A

  9. New Large Volume Press Beamlines at the Canadian Light Source

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.; Hormes, J.; Lauterjung, J.; Secco, R.; Hallin, E.

    2013-12-01

    The Canadian Light Source, the German Research Centre for Geosciences and the Western University recently agreed to establish two new large volume press beamlines at the Canadian Lightsource. As the first step a 250 tons DIA-LVP will be installed at the IDEAS beamline in 2014. The further development is associated with the construction of a superconducting wiggler beamline at the Brockhouse sector. A 1750 tons DIA LVP will be installed there about 2 years later. Up to the completion of this wiggler beamline the big press will be used for offline high pressure high temperature experiments under simulated Earth's mantle conditions. In addition to X-ray diffraction, all up-to-date high pressure techniques as ultrasonic interferometry, deformation analyses by X-radiography, X-ray densitometry, falling sphere viscosimetry, multi-staging etc. will be available at both beamlines. After the required commissioning the beamlines will be open to the worldwide user community from Geosciences, general material sciences, physics, chemistry, biology etc. based on the evaluation and ranking of the submitted user proposals by an international review panel.

  10. ProtoEXIST: The Development of Advanced Tiled CZT Detector Planes for Wide Field Hard X-Ray Survey Telescope

    NASA Astrophysics Data System (ADS)

    Allen, Branden; Hong, J.; Grindlay, J.; Barthelmy, S.; Baker, R.

    2011-05-01

    ProtoEXIST is a technology development program for a coded aperture hard X-ray telescope with a large area (1-5 m^2) CZT detector plane for use in a future hard X-ray wide field sky monitor and survey telescope. The successful flight of the ProtoEXIST1 (P1) coded-aperture telescope concluded the first phase of the program on October 9, 2009. The black hole binary Cyg X-1 was imaged and its spectrum measured at the end of the (6h) flight. The P1 detector plane is comprised of a 8x8 array of detector crystal units (DCUs); each made up of a single 20 mm x 20 mm, 5 mm thick Redlen CZT crystal with a 8x8 pixilated anode (pixel pitch of 2.5 mm) bonded to an interposer board connecting each of the individual 64 anode pixels to a single input channel on a RadNET ASIC, forming a 256 cm^2 contiguous CZT imaging array with 4096 individual pixels. P1 was successfully recovered and has undergone further characterization in the interim. The program continues with the ongoing development ProtoEXIST2 (P2) utilizing a closely tiled 8x8 array of DCUs now with a reduced anode pixel pitch of 0.6 mm. Each DCU in P2 will consist of a CZT crystal, identical to that utilized in P1 now with a 32x32 pixelated anode, directly bonded to a single NuSTAR ASIC (Nu-ASIC). The fully assembled P2 imaging detector will be comprised of a semi-contiguous 256x256 array of pixels on 256 cm^2 of CZT. With its finer pixelation the P2 detector plane will enable 5' (FWHM) imaging with a 70 cm focal length and will be flown side-by-side with P1 from Ft. Sumner in the Spring of 2012. Results from the characterization of the P1 detector are discussed as well as current progress in the development of the P2 detector plane.

  11. Characterization and selection of CZT detector modules for HEX experiment onboard Chandrayaan-1

    NASA Astrophysics Data System (ADS)

    Vadawale, S. V.; Purohit, S.; Shanmugam, M.; Acharya, Y. B.; Goswami, J. N.; Sudhakar, M.; Sreekumar, P.

    2009-01-01

    We present the results of characterization of a large sample of Cadmium Zinc Telluride (CZT) detector modules planned to be used for the HEX (High Energy X-ray spectrometer) experiment onboard India's first mission to the Moon, Chandrayaan-1. We procured forty modules from Orbotech Medical Solutions Ltd. and carried out a detailed characterization of each module at various temperatures and selected final nine detector modules for the flight model of HEX. Here we present the results of the characterization of all modules and the selection procedure for the HEX flight detector modules. These modules show 5-6% energy resolution (at 122 keV, for best 90% of pixels) at room temperature which is improved to ˜4% when these modules are cooled to sub-0 °C temperature. The gain and energy resolution were stable during the long duration tests.

  12. CZT detectors for high-energy flare spectroscopy: the Room Temperature Semiconductor Spectrometer (RTeSS) on the JAWSAT satellite

    NASA Astrophysics Data System (ADS)

    Vestrand, Thomas W.; Cutlip, H. H.; Forrest, D. J.; Levenson, Ken A.; Marci, J. R.; Ryan, James M.

    1998-07-01

    We report on the design and construction of a solar flare spectrometer that will employ four 15 X 15 X 15 mm CZT detectors with coplanar electrodes. The compact spectrometer, which will provide measurements in the 40 - 800 keV energy range, is being constructed for flight on the Joint Air Force Academy/Weber State University Satellite (JAWSAT). JAWSAT is scheduled for a Minuteman II launch into a 650 km sun-synchronous orbit early during the next solar maximum. The terminator orbit will allow our Room Temperature Semiconductor Spectrometer (RTeSS) to monitor solar hard x-ray and gamma-ray emission nearly continuously during the 23rd solar sunspot maximum. The primary scientific objective of the RTeSS is measurement of the broad line complex near 450 keV that is generated in solar flare spectra by the interaction of energetic alpha particles with helium in the solar atmosphere. The RTeSS spectral resolution of approximately 4% FWHM at 662 keV is well matched to the line splitting expected for likely alpha particle angular distributions and should allow us to place important constraints on the acceleration and the transport of flare ions. The primary technological objective of the RTeSS program is to test the feasibility of using CZT detectors for the construction of solar flare spectrometers that are capable of high resolution observations when operating at room temperature. If successful in low earth orbit, CZT solar flare spectrometers could lead to significant savings in mass, volume, and power consumption over conventional high-resolution spectrometers.

  13. Detailed Studies of Pixelated CZT Detectors Grown with the Modified Horizontal Bridgman Method

    NASA Technical Reports Server (NTRS)

    Jung, I.; Krawczynski, H.; Burger, A.; Guo, M.; Groza, M.

    2007-01-01

    The detector material Cadmium Zinc Telluride (CZT) achieves excellent spatial resolution and good energy resolution over a broad energy range, several keV up to some MeV. Presently, there are two main methods to grow CZT crystals, the Modified High-Pressure Bridgman (MHB) and the High-Pressure Bridgman (HPB) process. The study presented in this paper is based on MHB CZT substrates from the company Orbotech Medical Solutions Ltd. [Orbotech Medical Solutions Ltd., 10 Plaut St., Park Rabin, P.O. Box 2489, Rehovot, Israel, 76124]. Former studies have shown that high-work-function materials on the cathode side reduce the leakage current and, therefore, improve the energy resolution at lower energies. None of the studies have emphasized on the anode contact material. Therefore, we present in this paper the result of a detailed study in which for the first time the cathode material was kept constant and the anode material was varied. We used four different anode materials: Indium, Titanium, Chromium and Gold, metals with work-functions between 4.1 eV and 5.1 eV. The detector size was 2.0 x 2.0 x 0.5 cu cm with 8 x 8 pixels and a pitch of 2.46 mm. The best performance was achieved with the low-work-function materials Indium and Titanium with energy resolutions of 2.0 keV (at 59 keV) and 1.9 keV (at 122 keV) for Titanium and 2.1 keV (at 59 keV) and 2.9 keV (at 122 keV) for Indium. Taking into account the large pixel pitch of 2.46 mm, these resolutions are very competitive in comparison to those achieved with detectors made of material produced with the more expensive conventional HPB method. We present a detailed comparison of our detector response with 3D simulations. The latter comparisons allow us to determine the mobility-lifetime-products (mu tau-products) for electrons and holes. Finally, we evaluated the temperature dependency of the detector performance and ls-products. For many applications temperature dependence is important, therefore, we extended the scope of

  14. Spectroscopic CZT detectors development for x- and gamma-ray imaging instruments

    NASA Astrophysics Data System (ADS)

    Quadrini, Egidio M.; Uslenghi, Michela; Alderighi, Monica; Casini, Fabio; D'Angelo, Sergio; Fiorini, Mauro; La Palombara, Nicola; Mancini, Marcello; Monti, Serena; Bazzano, Angela; Di Cosimo, Sergio; Frutti, Massimo; Natalucci, Lorenzo; Ubertini, Pietro; Guadalupi, Giuseppe M.; Sassi, Matteo; Negri, Barbara

    2007-09-01

    In the context of R&D studies financed by the Italian Space Agency (ASI), a feasibility study to evaluate the Italian Industry interest in medium-large scale production of enhanced CZT detectors has been performed by an Italian Consortium. The R&D investment aims at providing in-house source of high quality solid state spectrometers for Space Astrophysics applications. As a possible spin-off industrial applications to Gamma-ray devices for non-destructive inspections in medical, commercial and security fields have been considered by ASI. The short term programme mainly consists of developing proprietary procedures for 2-3" CZT crystals growth, including bonding and contact philosophy, and a newly designed low-power electronics readout chain. The prototype design and breadboarding is based on a fast signal AD conversion with the target in order to perform a new run for an already existing low-power (<0.7 mW/pixel) ASIC. The prototype also provides digital photon energy reconstruction with particular care for multiple events and polarimetry evaluations. Scientific requirement evaluations for Space Astrophysics Satellite applications have been carried out in parallel, targeted to contribute to the ESA Cosmic Vision 2015-2025 Announcement of Opportunity. Detailed accommodation studies are undergoing, as part of this programme, to size a "Large area arcsecond angular resolution Imager" for the Gamma Ray Imager satellite (Knödlseder et al., this conference).and a new Gamma-ray Wide Field Camera for the "EDGE" proposal (Piro et al., this conference). Finally, an extended market study for cost analysis evaluation in view of the foreseen massive detector production has been performed.

  15. Characterisation of a CZT detector for dosimetry of molecular radiotherapy

    NASA Astrophysics Data System (ADS)

    McAreavey, L. H.; Harkness-Brennan, L. J.; Colosimo, S. J.; Judson, D. S.; Boston, A. J.; Boston, H. C.; Nolan, P. J.; Flux, G. D.; Denis-Bacelar, A. M.; Harris, B.; Radley, I.; Carroll, M.

    2017-03-01

    A pixelated cadmium zinc telluride (CZT) detector has been characterised for the purpose of developing a quantitative single photon emission computed tomography (SPECT) system for dosimetry of molecular radiotherapy (MRT). This is the aim of the Dosimetric Imaging with CZT (DEPICT) project, which is a collaboration between the University of Liverpool, The Royal Marsden Hospital, The Royal Liverpool and Broadgreen University Hospital, and the commercial partner Kromek. CZT is a direct band gap semiconductor with superior energy resolution and stopping power compared to scintillator detectors used in current SPECT systems. The inherent detector properties have been investigated and operational parameters such as bias voltage and peaking time have been selected to optimise the performance of the system. Good energy resolution is required to discriminate γ-rays that are scattered as they are emitted from the body and within the collimator, and high photon throughput is essential due to the high activities of isotopes administered in MRT. The system has an average measured electronic noise of 3.31 keV full width at half maximum (FWHM), determined through the use of an internal pulser. The energy response of the system was measured across the energy region of interest 59.5 keV to 364.5 keV and found to be linear. The reverse bias voltage and peaking time producing the optimum FWHM and maximum photon throughput were 600 V and 0.5 μs respectively. The average dead time of the system was measured as 4.84 μs and charge sharing was quantified to be 0.71 % at 59.5 keV . A pixel sensitivity calibration map was created and planar images of the medical imaging isotopes 99mTc and 123I were acquired by coupling the device to a prototype collimator, thereby demonstrating the suitability of the detector for the DEPICT project.

  16. Recent advances in CZT strip detectors and coded mask imagers

    NASA Astrophysics Data System (ADS)

    Matteson, J. L.; Gruber, D. E.; Heindl, W. A.; Pelling, M. R.; Peterson, L. E.; Rothschild, R. E.; Skelton, R. T.; Hink, P. L.; Slavis, K. R.; Binns, W. R.; Tumer, T.; Visser, G.

    1999-09-01

    The UCSD, WU, UCR and Nova collaboration has made significant progress on the necessary techniques for coded mask imaging of gamma-ray bursts: position sensitive CZT detectors with good energy resolution, ASIC readout, coded mask imaging, and background properties at balloon altitudes. Results on coded mask imaging techniques appropriate for wide field imaging and localization of gamma-ray bursts are presented, including a shadowgram and deconvolved image taken with a prototype detector/ASIC and MURA mask. This research was supported by NASA Grants NAG5-5111, NAG5-5114, and NGT5-50170.

  17. Design Studies of a CZT-based Detector Combined with a Pixel-Geometry-Matching Collimator for SPECT Imaging

    PubMed Central

    Weng, Fenghua; Bagchi, Srijeeta; Huang, Qiu; Seo, Youngho

    2014-01-01

    Single Photon Emission Computed Tomography (SPECT) suffers limited efficiency due to the need for collimators. Collimator properties largely decide the data statistics and image quality. Various materials and configurations of collimators have been investigated in many years. The main thrust of our study is to evaluate the design of pixel-geometry-matching collimators to investigate their potential performances using Geant4 Monte Carlo simulations. Here, a pixel-geometry-matching collimator is defined as a collimator which is divided into the same number of pixels as the detector’s and the center of each pixel in the collimator is a one-to-one correspondence to that in the detector. The detector is made of Cadmium Zinc Telluride (CZT), which is one of the most promising materials for applications to detect hard X-rays and γ-rays due to its ability to obtain good energy resolution and high light output at room temperature. For our current project, we have designed a large-area, CZT-based gamma camera (20.192 cm×20.192 cm) with a small pixel pitch (1.60 mm). The detector is pixelated and hence the intrinsic resolution can be as small as the size of the pixel. Materials of collimator, collimator hole geometry, detection efficiency, and spatial resolution of the CZT detector combined with the pixel-matching collimator were calculated and analyzed under different conditions. From the simulation studies, we found that such a camera using rectangular holes has promising imaging characteristics in terms of spatial resolution, detection efficiency, and energy resolution. PMID:25378898

  18. Property Improvement in CZT via Modeling and Processing Innovations . Te-particles in vertical gradient freeze CZT: Size and Spatial Distributions and Constitutional Supercooling

    SciTech Connect

    Henager, Charles H.; Alvine, Kyle J.; Bliss, Mary; Riley, Brian J.; Stave, Jean A.

    2014-10-01

    A section of a vertical gradient freeze CZT boule approximately 2100-mm3 with a planar area of 300-mm2 was prepared and examined using transmitted IR microscopy at various magnifications to determine the three-dimensional spatial and size distributions of Te-particles over large longitudinal and radial length scales. The boule section was approximately 50-mm wide by 60-mm in length by 7-mm thick and was doubly polished for TIR work. Te-particles were imaged through the thickness using extended focal imaging to locate the particles in thickness planes spaced 15-µm apart and then in plane of the image using xy-coordinates of the particle center of mass so that a true three dimensional particle map was assembled for a 1-mm by 45-mm longitudinal strip and for a 1-mm by 50-mm radial strip. Te-particle density distributions were determined as a function of longitudinal and radial positions in these strips, and treating the particles as vertices of a network created a 3D image of the particle spatial distribution. Te-particles exhibited a multi-modal log-normal size density distribution that indicated a slight preference for increasing size with longitudinal growth time, while showing a pronounced cellular network structure throughout the boule that can be correlated to dislocation network sizes in CZT. Higher magnification images revealed a typical Rayleigh-instability pearl string morphology with large and small satellite droplets. This study includes solidification experiments in small crucibles of 30:70 mixtures of Cd:Te to reduce the melting point below 1273 K (1000°C). These solidification experiments were performed over a wide range of cooling rates and clearly demonstrated a growth instability with Te-particle capture that is suggested to be responsible for one of the peaks in the size distribution using size discrimination visualization. The results are discussed with regard to a manifold Te-particle genesis history as 1) Te

  19. Large-volume leukaphereses may be more efficient than standard-volume leukaphereses for collection of peripheral blood progenitor cells.

    PubMed

    Passos-Coelho, J L; Machado, M A; Lúcio, P; Leal-Da-Costa, F; Silva, M R; Parreira, A

    1997-10-01

    To overcome the need for multiple leukaphereses to collect enough PBPC for autologous transplantation, large-volume leukaphereses (LVL) are used to process multiple blood volumes per session. We compared the efficiency of CD34+ cell collection by LVL (n = 63; median blood volumes processed 11.1) with that of standard-volume leukaphereses (SVL) (n = 38; median blood volumes processed 1.9). To achieve this in patients with different peripheral blood concentrations of CD34+ cells, we analyzed the ratio of CD34+ cells collected per unit of blood volume processed, divided by the number of CD34+ cells in total blood volume at the beginning of apheresis. For LVL, 30% (9%-323%) of circulating CD34+ cells were collected per blood volume compared with 42% (7%-144%) for SVL (p = 0.02). However, in LVL patients, peripheral blood CD34+ cells/L decreased a median of 54% during LVL (similar data for SVL not available). The number of CD34+ cells collected per blood volume processed after 4 and 8 blood volumes and at the end of LVL were 0.32 (0.01-2.05), 0.24 (0.01-1.68), and 0.22 (0.01-2.40) x 10(6) CD34+ cells/kg, respectively (p = 0.0007), despite the 54% decrease in peripheral blood CD34+ cells/L throughout LVL. A median 66% decrease in the platelet count was also observed during LVL. Thus, LVL may be more efficient than SVL for PBPC collection, allowing, in most patients, the collection in one LVL of sufficient PBPC to support autologous transplantation.

  20. Large space telescope, phase A. Volume 3: Optical telescope assembly

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development and characteristics of the optical telescope assembly for the Large Space Telescope are discussed. The systems considerations are based on mission-related parameters and optical equipment requirements. Information is included on: (1) structural design and analysis, (2) thermal design, (3) stabilization and control, (4) alignment, focus, and figure control, (5) electronic subsystem, and (6) scientific instrument design.

  1. RADON DIAGNOSTIC MEASUREMENT GUIDANCE FOR LARGE BUILDINGS - VOLUME 2. APPENDICES

    EPA Science Inventory

    The report discusses the development of radon diagnostic procedures and mitigation strategies applicable to a variety of large non-residential buildings commonly found in Florida. The investigations document and evaluate the nature of radon occurrence and entry mechanisms for rad...

  2. Large space telescope, phase A. Volume 4: Scientific instrument package

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The design and characteristics of the scientific instrument package for the Large Space Telescope are discussed. The subjects include: (1) general scientific objectives, (2) package system analysis, (3) scientific instrumentation, (4) imaging photoelectric sensors, (5) environmental considerations, and (6) reliability and maintainability.

  3. Large space telescope, phase A. Volume 5: Support systems module

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development and characteristics of the support systems module for the Large Space Telescope are discussed. The following systems and described: (1) thermal control, (2) electrical, (3) communication and data landing, (4) attitude control system, and (5) structural features. Analyses of maintainability and reliability considerations are included.

  4. Simultaneous CT and SPECT tomography using CZT detectors

    DOEpatents

    Paulus, Michael J.; Sari-Sarraf, Hamed; Simpson, Michael L.; Britton, Jr., Charles L.

    2002-01-01

    A method for simultaneous transmission x-ray computed tomography (CT) and single photon emission tomography (SPECT) comprises the steps of: injecting a subject with a tracer compound tagged with a .gamma.-ray emitting nuclide; directing an x-ray source toward the subject; rotating the x-ray source around the subject; emitting x-rays during the rotating step; rotating a cadmium zinc telluride (CZT) two-sided detector on an opposite side of the subject from the source; simultaneously detecting the position and energy of each pulsed x-ray and each emitted .gamma.-ray captured by the CZT detector; recording data for each position and each energy of each the captured x-ray and .gamma.-ray; and, creating CT and SPECT images from the recorded data. The transmitted energy levels of the x-rays lower are biased lower than energy levels of the .gamma.-rays. The x-ray source is operated in a continuous mode. The method can be implemented at ambient temperatures.

  5. Real-time visualization of large volume datasets on standard PC hardware.

    PubMed

    Xie, Kai; Yang, Jie; Zhu, Y M

    2008-05-01

    In medical area, interactive three-dimensional volume visualization of large volume datasets is a challenging task. One of the major challenges in graphics processing unit (GPU)-based volume rendering algorithms is the limited size of texture memory imposed by current GPU architecture. We attempt to overcome this limitation by rendering only visible parts of large CT datasets. In this paper, we present an efficient, high-quality volume rendering algorithm using GPUs for rendering large CT datasets at interactive frame rates on standard PC hardware. We subdivide the volume dataset into uniform sized blocks and take advantage of combinations of early ray termination, empty-space skipping and visibility culling to accelerate the whole rendering process and render visible parts of volume data. We have implemented our volume rendering algorithm for a large volume data of 512 x 304 x 1878 dimensions (visible female), and achieved real-time performance (i.e., 3-4 frames per second) on a Pentium 4 2.4GHz PC equipped with NVIDIA Geforce 6600 graphics card ( 256 MB video memory). This method can be used as a 3D visualization tool of large CT datasets for doctors or radiologists.

  6. Balloon flight background measurement with actively-shielded planar and imaging CZT detectors

    NASA Astrophysics Data System (ADS)

    Bloser, Peter F.; Narita, Tomohiko; Jenkins, Jonathan A.; Perrin, Marshall; Murray, Ruth; Grindlay, Jonathan E.

    2002-01-01

    We present results from the flight of two prototype CZT detectors on a scientific balloon payload in September 2000. The first detector, referred to as CZT1, consisted of a 10 mm x 10 mm x 2 mm CZT crystal with a single gold planar electrode readout. This detector was shielded by a combination of a passive collimator in the front, giving a 40 degree field of view and surrounded by plastic scintillator, and a thick BGO crystal in the rear. The second detector, CZT2, comprised two 10 mm x 10 mm x 5 mm CZT crystals, one made of eV Products high pressure Bridgman material and the other of IMARAD horizontal Bridgman material, each fashioned with a 4 x 4 array of gold pixels on a 2.5 mm pitch. The pixellated detectors were flip-chip-mounted side by side and read out by a 32-channel ASIC. This detector was also shielded by a passive/plastic collimator in the front, but used only additional passive/plastic shielding in the rear. Both experiments were flown from Ft. Sumner, NM on September 19, 2000 on a 24 hour balloon flight. Both instruments performed well. CZT1 recorded a non-vetoed background level at 100 keV of approximately 1 x 10-3 cm-2s-1keV-1. Raising the BGO threshold from 50 keV to approximately 1 MeV produced only an 18% increase in this level. CZT2 recorded a background at 100 keV of approximately 4 times 10-3 cts cm-2s-1keV-1 in the eV Products detector and approximately 6 x 10-3 cts cm-2s-1keV-1 in the IMARAD detector, a difference possibly due to our internal background subtracting procedure. Both CZT1 and CZT2 spectra were in basic agreement with Monte Carlo simulations, though both recorded systematically higher count rates at high energy than predicted. No lines were observed, indicating that neutron capture reactions, at least those producing decay lines at a few 100 keV, are not significant components of the CZT background. Comparison of the CZT1 and CZT2 spectra indicates that passive/plastic shielding may provide adequately low background levels for

  7. Radiation from Large Gas Volumes and Heat Exchange in Steam Boiler Furnaces

    SciTech Connect

    Makarov, A. N.

    2015-09-15

    Radiation from large cylindrical gas volumes is studied as a means of simulating the flare in steam boiler furnaces. Calculations of heat exchange in a furnace by the zonal method and by simulation of the flare with cylindrical gas volumes are described. The latter method is more accurate and yields more reliable information on heat transfer processes taking place in furnaces.

  8. An instrument for collecting discrete large-volume water samples suitable for ecological studies of microorganisms

    NASA Astrophysics Data System (ADS)

    Wommack, K. Eric; Williamson, Shannon J.; Sundbergh, Arthur; Helton, Rebekah R.; Glazer, Brian T.; Portune, Kevin; Craig Cary, S.

    2004-11-01

    Microbiological investigations utilizing molecular genetic approaches to characterize microbial communities can require large volume water samples, tens to hundreds of liters. The requirement for large volume samples can be especially challenging in deep-sea hydrothermal vent environments of the oceanic ridge system. By and large studies of these environments rely on deep submergence vehicles. However collection of large volume (>100 L) water samples adjacent to the benthos is not feasible due to weight considerations. To address the technical difficulty of collecting large volume water samples from hydrothermal diffuse flow environments, a semi-autonomous large-volume water sampler (LVWS) was designed. The LVWS is capable of reliably collecting and bringing to the surface 120 L water samples from diffuse flow environments. Microscopy, molecular genetic and chemical analyses of water samples taken from 9°N East Pacific Rise are shown to demonstrate the utility of the LVWS for studies of near-benthos environments. To our knowledge this is the first report of virioplankton abundance within diffuse-flow waters of a deep-sea hydrothermal vent environment. Because of its simple design and relatively low cost, the LVWS should be applicable to a variety of studies which require large-volume water samples collected immediately adjacent to the benthos.

  9. Large-volume protein crystal growth for neutron macromolecular crystallography

    SciTech Connect

    Ng, Joseph D.; Baird, James K.; Coates, Leighton; Garcia-Ruiz, Juan M.; Hodge, Teresa A.; Huang, Sijay

    2015-03-30

    Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction. However, owing to new-generation synchrotron X-ray facilities and sensitive detectors, protein crystal sizes as small as in the nano-range have become adequate for structure determination, lessening the necessity to grow large crystals. Here, some of the approaches, techniques and considerations for the growth of crystals to significant dimensions that are now relevant to NMC are revisited. We report that these include experimental strategies utilizing solubility diagrams, ripening effects, classical crystallization techniques, microgravity and theoretical considerations.

  10. Large-volume protein crystal growth for neutron macromolecular crystallography

    DOE PAGES

    Ng, Joseph D.; Baird, James K.; Coates, Leighton; ...

    2015-03-30

    Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction. However, owing to new-generation synchrotron X-ray facilities and sensitive detectors, protein crystal sizes as small as in the nano-range have become adequate for structure determination, lessening the necessity to grow large crystals. Here, some of the approaches, techniques and considerations for themore » growth of crystals to significant dimensions that are now relevant to NMC are revisited. We report that these include experimental strategies utilizing solubility diagrams, ripening effects, classical crystallization techniques, microgravity and theoretical considerations.« less

  11. Sand tank experiment of a large volume biodiesel spill

    NASA Astrophysics Data System (ADS)

    Scully, K.; Mayer, K. U.

    2015-12-01

    Although petroleum hydrocarbon releases in the subsurface have been well studied, the impacts of subsurface releases of highly degradable alternative fuels, including biodiesel, are not as well understood. One concern is the generation of CH4­ which may lead to explosive conditions in underground structures. In addition, the biodegradation of biodiesel consumes O2 that would otherwise be available for the degradation of petroleum hydrocarbons that may be present at a site. Until now, biodiesel biodegradation in the vadose zone has not been examined in detail, despite being critical to understanding the full impact of a release. This research involves a detailed study of a laboratory release of 80 L of biodiesel applied at surface into a large sandtank to examine the progress of biodegradation reactions. The experiment will monitor the onset and temporal evolution of CH4 generation to provide guidance for site monitoring needs following a biodiesel release to the subsurface. Three CO2 and CH4 flux chambers have been deployed for long term monitoring of gas emissions. CO2 fluxes have increased in all chambers over the 126 days since the start of the experiment. The highest CO2 effluxes are found directly above the spill and have increased from < 0.5 μmol m-2 s-1 to ~3.8 μmol m-2 s-1, indicating an increase in microbial activity. There were no measurable CH4 fluxes 126 days into the experiment. Sensors were emplaced to continuously measure O2, CO2, moisture content, matric potential, EC, and temperature. In response to the release, CO2 levels have increased across all sensors, from an average value of 0.1% to 0.6% 126 days after the start of the experiment, indicating the rapid onset of biodegradation. The highest CO2 values observed from samples taken in the gas ports were 2.5%. Average O2 concentrations have decreased from 21% to 17% 126 days after the start of the experiment. O2 levels in the bottom central region of the sandtank declined to approximately 12%.

  12. Large Variations in Ice Volume During the Middle Eocene "Doubthouse"

    NASA Astrophysics Data System (ADS)

    Dawber, C. F.; Tripati, A. K.

    2008-12-01

    The onset of glacial conditions in the Cenozoic is widely held to have begun ~34 million years ago, coincident with the Eocene-Oligocene boundary1. Warm and high pCO2 'greenhouse' intervals such as the Eocene are generally thought to be ice-free2. Yet the sequence stratigraphic record supports the occurrence of high-frequency sea-level change of tens of meters in the Middle and Late Eocene3, and large calcite and seawater δ18O excursions (~0.5-1.0 permil) have been reported in foraminifera from open ocean sediments4. As a result, the Middle Eocene is often considered the intermediary "doubthouse". The extent of continental ice during the 'doubthouse' is controversial, with estimates of glacioeustatic sea level fall ranging from 30 to 125m2,3,5. We present a new δ18Osw reconstruction for Ocean Drilling Project (ODP) Site 1209 in the tropical Pacific Ocean. It is the first continuous high-resolution record for an open-ocean site that is not directly influenced by changes in the carbonate compensation depth, which enables us to circumvent many of the limitations of existing records. Our record shows increases of 0.8 ± 0.2 (1 s.e) permil and 1.1 ± 0.2 permil at ~44-45 and ~42-41 Ma respectively, which suggests glacioeustatic sea level variations of ~90 m during the Middle Eocene. Modelling studies have shown that fully glaciating Antarctica during the Eocene should drive a change in seawater (δ18Osw) of 0.45 permil, and lower sea level by ~55 m6. Our results therefore support significant ice storage in both the Northern and Southern Hemisphere during the Middle Eocene 'doubthouse'. 1.Miller, Kenneth G. et al., 1990, Eocene-Oligocene sea-level changes in the New Jersey coastal plain linked to the deep-sea record. Geological Society of America Bulletin 102, 331-339 2.Pagani, M. et al., 2005, Marked decline in atmospheric carbon dioxide concentrations during the Paleogene. Science 309 (5734), 600-603. 3.Browning, J., Miller, K., and Pak, D., 1996, Global implications

  13. AstroSat CZT Imager Observations of GRB 151006A: Timing, Spectroscopy, and Polarization Study

    NASA Astrophysics Data System (ADS)

    Rao, A. R.; Chand, Vikas; Hingar, M. K.; Iyyani, S.; Khanna, Rakesh; Kutty, A. P. K.; Malkar, J. P.; Paul, D.; Bhalerao, V. B.; Bhattacharya, D.; Dewangan, G. C.; Pawar, Pramod; Vibhute, A. M.; Chattopadhyay, T.; Mithun, N. P. S.; Vadawale, S. V.; Vagshette, N.; Basak, R.; Pradeep, P.; Samuel, Essy; Sreekumar, S.; Vinod, P.; Navalgund, K. H.; Pandiyan, R.; Sarma, K. S.; Seetha, S.; Subbarao, K.

    2016-12-01

    AstroSat is a multi-wavelength satellite launched on 2015 September 28. The CZT Imager of AstroSat on its very first day of operation detected a long duration gamma-ray burst (GRB), namely GRB 151006A. Using the off-axis imaging and spectral response of the instrument, we demonstrate that the CZT Imager can localize this GRB correctly to about a few degrees, and it can provide, in conjunction with Swift, spectral parameters similar to those obtained from Fermi/GBM. Hence, the CZT Imager would be a useful addition to the currently operating GRB instruments (Swift and Fermi). Specifically, we argue that the CZT Imager will be most useful for the short hard GRBs by providing localization for those detected by Fermi and spectral information for those detected only by Swift. We also provide preliminary results on a new exciting capability of this instrument: the CZT Imager is able to identify Compton scattered events thereby providing polarization information for bright GRBs. GRB 151006A, in spite of being relatively faint, shows hints of a polarization signal at 100-300 keV (though at a low significance level). We point out that the CZT Imager should provide significant time resolved polarization measurements for GRBs that have fluence three times higher than that of GRB 151006A. We estimate that the number of such bright GRBs detectable by the CZT Imager is five to six per year. The CZT Imager can also act as a good hard X-ray monitoring device for possible electromagnetic counterparts of gravitational wave events.

  14. Epitaxial growth of CZT(S,Se) on silicon

    DOEpatents

    Bojarczuk, Nestor A.; Gershon, Talia S.; Guha, Supratik; Shin, Byungha; Zhu, Yu

    2016-03-15

    Techniques for epitaxial growth of CZT(S,Se) materials on Si are provided. In one aspect, a method of forming an epitaxial kesterite material is provided which includes the steps of: selecting a Si substrate based on a crystallographic orientation of the Si substrate; forming an epitaxial oxide interlayer on the Si substrate to enhance wettability of the epitaxial kesterite material on the Si substrate, wherein the epitaxial oxide interlayer is formed from a material that is lattice-matched to Si; and forming the epitaxial kesterite material on a side of the epitaxial oxide interlayer opposite the Si substrate, wherein the epitaxial kesterite material includes Cu, Zn, Sn, and at least one of S and Se, and wherein a crystallographic orientation of the epitaxial kesterite material is based on the crystallographic orientation of the Si substrate. A method of forming an epitaxial kesterite-based photovoltaic device and an epitaxial kesterite-based device are also provided.

  15. Design and development of the RT-2/CZT payload

    NASA Astrophysics Data System (ADS)

    Malkar, J. P.; Tawde, Amit; Sreekumar, S.; Hingar, M. K.; Chakrabarti, S. K.; Nandi, Anuj

    The RT-2/CZT spectrometer is one of the satellite payloads to be flown onboard the Coronas-Photon satellite in 2008. It is a collaborative experiment between TIFR, CSP, ISRO (India) and MEPhI (Russia). It is designed to study the solar hard X-ray flare phenomena in the energy range 20 keV - 120 keV using pixilated (2.5 mm times 2.5 mm) cadmium zinc telluride detector array. These detectors along with an image coding device like coded aperture mask (CAM) or fresnel zone plate (FZP) helps in to snap images (in medium X-ray energy ranges) of the solar flares. The design characteristics of this payload are discussed.

  16. HEXITEC ASIC—a pixellated readout chip for CZT detectors

    NASA Astrophysics Data System (ADS)

    Jones, Lawrence; Seller, Paul; Wilson, Matthew; Hardie, Alec

    2009-06-01

    HEXITEC is a collaborative project with the aim of developing a new range of detectors for high-energy X-ray imaging. High-energy X-ray imaging has major advantages over current lower energy imaging for the life and physical sciences, including improved phase-contrast images on larger, higher density samples and with lower accumulated doses. However, at these energies conventional silicon-based devices cannot be used, hence, the requirement for a new range of high Z-detector materials. Underpinning the HEXITEC programme are the development of a pixellated Cadmium Zinc Telluride (CZT) detectors and a pixellated readout ASIC which will be bump-bonded to the detector. The HEXITEC ASIC is required to have low noise (20 electrons rms) and tolerate detector leakage currents. A prototype 20×20 pixel ASIC has been developed and manufactured on a standard 0.35 μm CMOS process.

  17. Development of Tiled Imaging CZT Detectors for Sensitive Wide-Field Hard X-Ray Surveys to EXIST

    NASA Technical Reports Server (NTRS)

    Grindlay, J.; Hong, J.; Allen, B.; Barthelmy, S.; Baker, R.

    2011-01-01

    Motivated by the proposed EXIST mission, a "medium-class" space observatory to survey black holes and the Early Universe proposed to the 2010 NAS/NRC Astronomy and Astrophysics Decadal Survey, we have developed the first "large" area 256 sq cm close-tiled (0.6 mm gaps) hard X-ray (20-600 keV) imaging detector employing pixelated (2.5 mm) CdZnTe (CZT) detectors, each 2 x 2 x 0.5 cubic cm. We summarize the design, development and operation of this detector array (8 x 8 CZTs) and its performance as the imager for a coded aperture telescope on a high altitude (40 km) balloon flight in October. 2009, as the ProtoEX1STl payload. We then outline our current development of a second-generation imager, ProtcEXIST2. with 0.6 mm pixels on a 32 x 32 array on each CZT, and how it will lead to the ultimate imaging system needed for EXIST. Other applications of this technology will also be mentioned.

  18. Center-stabilized Yang-Mills Theory:Confinement and Large N Volume Independence

    SciTech Connect

    Unsal, Mithat; Yaffe, Laurence G.; /Washington U., Seattle

    2008-03-21

    We examine a double trace deformation of SU(N) Yang-Mills theory which, for large N and large volume, is equivalent to unmodified Yang-Mills theory up to O(1/N{sup 2}) corrections. In contrast to the unmodified theory, large N volume independence is valid in the deformed theory down to arbitrarily small volumes. The double trace deformation prevents the spontaneous breaking of center symmetry which would otherwise disrupt large N volume independence in small volumes. For small values of N, if the theory is formulated on R{sup 3} x S{sup 1} with a sufficiently small compactification size L, then an analytic treatment of the non-perturbative dynamics of the deformed theory is possible. In this regime, we show that the deformed Yang-Mills theory has a mass gap and exhibits linear confinement. Increasing the circumference L or number of colors N decreases the separation of scales on which the analytic treatment relies. However, there are no order parameters which distinguish the small and large radius regimes. Consequently, for small N the deformed theory provides a novel example of a locally four-dimensional pure gauge theory in which one has analytic control over confinement, while for large N it provides a simple fully reduced model for Yang-Mills theory. The construction is easily generalized to QCD and other QCD-like theories.

  19. Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement

    SciTech Connect

    ROY, U.N.; JAMES, R.; WEILER, S.; STEIN, J.; GROZA, M.; BURGER, A.; BOLOTNIKOV, A.E.; CAMARDA, G.S.; HOSSAIN, A.; YANG, G.

    2011-04-25

    In this present work we report the growth of Cd{sub 0.9}Zn{sub 0.1}Te doped with In by a modified THM technique. It has been demonstrated that by controlling the microscopically flat growth interface, the size distribution and concentration can be drastically reduced in the as-grown ingots. This results in as-grown detector-grade CZT by the THM technique. The three-dimensional size distribution and concentrations of Te inclusions/precipitations were studied. The size distributions of the Te precipitations/inclusions were observed to be below the 10-{micro}m range with the total concentration less than 10{sup 5} cm{sup -3}. The relatively low value of Te inclusions/precipitations results in excellent charge transport properties of our as-grown samples. The ({mu}{tau}){sub e} values for different as-grown samples varied between 6-20 x 10{sup -3} cm{sup 2}/V. The as-grown samples also showed fairly good detector response with resolution of {approx}1.5%, 2.7% and about 3.8% at 662 keV for quasi-hemispherical geometry for detector volumes of 0.18 cm{sup 3}, 1 cm{sup 3} and 4.2 cm{sup 3}, respectively.

  20. Instruments of RT-2 experiment onboard CORONAS-PHOTON and their test and evaluation II: RT-2/CZT payload

    NASA Astrophysics Data System (ADS)

    Kotoch, Tilak B.; Nandi, Anuj; Debnath, D.; Malkar, J. P.; Rao, A. R.; Hingar, M. K.; Madhav, Vaibhav P.; Sreekumar, S.; Chakrabarti, Sandip K.

    2011-02-01

    Cadmium Zinc Telluride (CZT) detectors are high sensitivity and high resolution devices for hard X-ray imaging and spectroscopic studies. The new series of CZT detector modules (OMS40G256) manufactured by Orbotech Medical Solutions (OMS), Israel, are used in the RT-2/CZT payload onboard the CORONAS-PHOTON satellite. The CZT detectors, sensitive in the energy range of 20 to 150 keV, are used to image solar flares in hard X-rays. Since these modules are essentially manufactured for commercial applications, we have carried out a series of comprehensive tests on these modules so that they can be confidently used in space-borne systems. These tests lead us to select the best three pieces of the `Gold' modules for the RT-2/CZT payload. This paper presents the characterization of CZT modules and the criteria followed for selecting the ones for the RT-2/CZT payload. The RT-2/CZT payload carries, along with three CZT modules, a high spatial resolution CMOS detector for high resolution imaging of transient X-ray events. Therefore, we discuss the characterization of the CMOS detector as well.

  1. Production of large resonant plasma volumes in microwave electron cyclotron resonance ion sources

    DOEpatents

    Alton, G.D.

    1998-11-24

    Microwave injection methods are disclosed for enhancing the performance of existing electron cyclotron resonance (ECR) ion sources. The methods are based on the use of high-power diverse frequency microwaves, including variable-frequency, multiple-discrete-frequency, and broadband microwaves. The methods effect large resonant ``volume`` ECR regions in the ion sources. The creation of these large ECR plasma volumes permits coupling of more microwave power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present ECR ion sources. 5 figs.

  2. Production of large resonant plasma volumes in microwave electron cyclotron resonance ion sources

    DOEpatents

    Alton, Gerald D.

    1998-01-01

    Microwave injection methods for enhancing the performance of existing electron cyclotron resonance (ECR) ion sources. The methods are based on the use of high-power diverse frequency microwaves, including variable-frequency, multiple-discrete-frequency, and broadband microwaves. The methods effect large resonant "volume" ECR regions in the ion sources. The creation of these large ECR plasma volumes permits coupling of more microwave power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present ECR ion sources.

  3. Rapid estimate of solid volume in large tuff cores using a gas pycnometer

    SciTech Connect

    Thies, C.; Geddis, A.M.; Guzman, A.G.

    1996-09-01

    A thermally insulated, rigid-volume gas pycnometer system has been developed. The pycnometer chambers have been machined from solid PVC cylinders. Two chambers confine dry high-purity helium at different pressures. A thick-walled design ensures minimal heat exchange with the surrounding environment and a constant volume system, while expansion takes place between the chambers. The internal energy of the gas is assumed constant over the expansion. The ideal gas law is used to estimate the volume of solid material sealed in one of the chambers. Temperature is monitored continuously and incorporated into the calculation of solid volume. Temperature variation between measurements is less than 0.1{degrees}C. The data are used to compute grain density for oven-dried Apache Leap tuff core samples. The measured volume of solid and the sample bulk volume are used to estimate porosity and bulk density. Intrinsic permeability was estimated from the porosity and measured pore surface area and is compared to in-situ measurements by the air permeability method. The gas pycnometer accommodates large core samples (0.25 m length x 0.11 m diameter) and can measure solid volume greater than 2.20 cm{sup 3} with less than 1% error.

  4. Large-volume diamond cells for neutron diffraction above 90GPa

    SciTech Connect

    Boehler, Reinhard; Guthrie, Malcolm; Molaison, Jamie J; Moreira Dos Santos, Antonio F; Sinogeikin, Stanislav; Machida, Shinichi; Pradhan, Neelam; Tulk, Christopher A

    2013-01-01

    Quantitative high pressure neutron-diffraction measurements have traditionally required large sample volumes of at least 25 mm3 due to limited neutron flux. Therefore, pressures in these experiments have been limited to below 25 GPa. In comparison, for X-ray diffraction, sample volumes in conventional diamond cells for pressures up to 100 GPa have been less than 1 10 4 mm3. Here, we report a new design of strongly supported conical diamond anvils for neutron diffraction that has reached 94 GPa with a sample volume of 2 10 2 mm3, a 100-fold increase. This sample volume is sufficient to measure full neutron-diffraction patterns of D2O ice to this pressure at the high flux Spallation Neutrons and Pressure beamline at the Oak Ridge National Laboratory. This provides an almost fourfold extension of the previous pressure regime for such measurements.

  5. Mechanically Cooled Large-Volume Germanium Detector Systems for Nuclear Explosion Monitoring DOENA27323-1

    SciTech Connect

    Hull, E.L.

    2006-07-28

    Compact maintenance free mechanical cooling systems are being developed to operate large volume germanium detectors for field applications. To accomplish this we are utilizing a newly available generation of Stirling-cycle mechanical coolers to operate the very largest volume germanium detectors with no maintenance. The user will be able to leave these systems unplugged on the shelf until needed. The flip of a switch will bring a system to life in ~ 1 hour for measurements. The maintenance-free operating lifetime of these detector systems will exceed 5 years. These features are necessary for remote long-duration liquid-nitrogen free deployment of large-volume germanium gamma-ray detector systems for Nuclear Explosion Monitoring. The Radionuclide Aerosol Sampler/Analyzer (RASA) will greatly benefit from the availability of such detectors by eliminating the need for liquid nitrogen at RASA sites while still allowing the very largest available germanium detectors to be reliably utilized.

  6. High Energy Performance Tests of Large Volume LaBr{sub 3}:Ce Detector

    SciTech Connect

    Naqvi, A.A.; Gondal, M.A.; Khiari, F.Z.; Dastageer, M.A.; Maslehuddin, M.M.; Al-Amoudi, O.S.B.

    2015-07-01

    High energy prompt gamma ray tests of a large volume cylindrical 100 mm x 100 mm (height x diameter) LaBr{sub 3}:Ce detector were carried out using a portable neutron generator-based Prompt Gamma Neutron Activation Analysis (PGNAA) setup. In this study prompt gamma-rays yield were measured from water samples contaminated with toxic elements such nickel, chromium and mercury compounds with gamma ray energies up to 10 MeV. The experimental yield of prompt gamma-rays from toxic elements were compared with the results of Monte Carlo calculations. In spite of its higher intrinsic background due to its larger volume, an excellent agreement between the experimental and calculated yields of high energy gamma-rays from Ni, Cr and Hg samples has been achieved for the large volume LaBr{sub 3}:Ce detector. (authors)

  7. Development of a CZT drift ring detector for X and γ ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Alruhaili, A.; Sellin, P. J.; Lohstroh, A.; Boothman, V.; Veeramani, P.; Veale, M. C.; Sawhney, K. J. S.; Kachkanov, V.

    2015-04-01

    CdTe and CZT detectors are considered better choices for high energy γ and X-ray spectroscopy in comparison to Si and HPGe detectors due to their good quantum efficiency and room temperature operation. The performance limitations in CdTe and CZT detectors are mainly associated with poor hole transport and trapping phenomena. Among many techniques that can be used to eliminate the effect of the poor charge transport properties of holes in CdTe and CZT material, the drift ring technique shows promising results. In this work, the performance of a 2.3 mm thick CZT drift ring detector is investigated. Spatially resolved measurements were carried out with an X-ray microbeam (25 and 75 keV) at the Diamond Light Source synchrotron to study the response uniformity and extent of the active area. Higher energy photon irradiation was also carried out at up to 662 keV using different radioisotopes to complement the microbeam data. Different biasing schemes were investigated in terms of biasing the cathode rear electrode (bulk field) and the ring electrodes (lateral fields). The results show that increasing the bulk field with fixed-ratio ring biases and lateral fields with fixed bulk fields increase the active area of the device significantly, which contrasts with previous studies in CdTe, where only an increasing lateral field resulted in an improvement of device performance. This difference is attributed to the larger thickness of the CZT device reported here.

  8. Development of CZT detectors for x-ray and gamma-ray astronomy

    NASA Astrophysics Data System (ADS)

    Lee, Kuen; Martin, J. W.; Garson, A., III; Guo, Q.; Matteson, J.; Groza, M.; Beilicke, M.; Burger, A.; de Geronimo, G.; Krawczynski, H.

    2011-09-01

    Cadmium Zinc Telluride (CZT) is the detector material of choice for the detection of X-rays in the 10 keV-1MeV energy band with excellent spatial and energy resolutions and without cryogenic cooling. In this contribution, we report on recent results of the CZT detector development program and several astrophysical experiments which make use of CZT detectors. In the first part of the paper, we discuss the performance of pixel and cross-strip CZT detectors read out with an ASIC developed at the Brookhaven National Laboratory. Our pixel detectors achieve some of the best energy resolutions reported in the literature. Cross-strip detectors are found to give an inferior performance and we investigate the reason for this performance difference. We also present results from a precision measurement of the effect of a steering grid on multi-pixel events obtained with a 200 micrometer collimator. In the second part of the paper, we describe the design and performance of the hard X-ray polarimeter X-Calibur. The polarimeter uses a 14 cm long scintillator scatterer, surrounded by an assembly of 32 2-5 mm thick CZT detectors. We discuss the sensitivity of the polarimeter to measure the linear polarization of 10 keV-80 keV X-rays on short and long balloon flights and results from testing the polarimeter in the laboratory.

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

    EPA Science Inventory

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

  10. A New Electropositive Filter for Concentrating Enterovirus and Norovirus from Large Volumes of Water - MCEARD

    EPA Science Inventory

    The detection of enteric viruses in environmental water usually requires the concentration of viruses from large volumes of water. The 1MDS electropositive filter is commonly used for concentrating enteric viruses from water but unfortunately these filters are not cost-effective...

  11. CZT detectors for a new generation of γ-ray telescopes

    NASA Astrophysics Data System (ADS)

    Quadrini, Egidio M.; Conti, Giancarlo; D'Angelo, Sergio; Fiorini, Mauro; Uslenghi, Michela; Natalucci, Lorenzo; Ubertini, Pietro

    2005-08-01

    The outstanding scientific performances of IBIS, Imager on Board INTEGRAL, has encouraged preliminary feasibility studies on new Gamma Ray instruments. We considered both a Wide Field Camera for transient event detection and fast automatic sky localisation and a high resolution imager. According to the basic scientific requirements, i.e. to operate with good sensitivity (1mCrab/day) and spatial resolution (from arcmin to arcsec) on a wide energy range (5 to 500 keV), these studies consider large detector area (from 1 to several m2) and a high number (~50000) of thick (≥ 5mm) pixels. Recent achievements already obtained by INTEGRAL, and initially showed by SWIFT, have validated the CdTe/CZT detector performances in terms of good spatial resolution, detection efficiency, energy resolution and low noise at room temperature. We have started a study to solve peculiar problems affecting this kind of detectors (e.g. response dependent on the interaction depth and multiple hit events) using a digital approach to photon reconstruction. This also facilitates operations like pixel to pixel equalisation and background rejection. The detector electronic chain thus includes a minimal analog stage for charge pre-amplification, coupled to a flash ADC for waveform digitalisation at a high time resolution sampling, and a powerful, FPGA based digital processing unit, devoted to waveform elaboration. Such a design should also help in optimising the telemetry flux and allow polarimetry evaluation on multiple events.

  12. Evaluation of Bacillus oleronius as a Biological Indicator for Terminal Sterilization of Large-Volume Parenterals.

    PubMed

    Izumi, Masamitsu; Fujifuru, Masato; Okada, Aki; Takai, Katsuya; Takahashi, Kazuhiro; Udagawa, Takeshi; Miyake, Makoto; Naruyama, Shintaro; Tokuda, Hiroshi; Nishioka, Goro; Yoden, Hikaru; Aoki, Mitsuo

    2016-01-01

    In the production of large-volume parenterals in Japan, equipment and devices such as tanks, pipework, and filters used in production processes are exhaustively cleaned and sterilized, and the cleanliness of water for injection, drug materials, packaging materials, and manufacturing areas is well controlled. In this environment, the bioburden is relatively low, and less heat resistant compared with microorganisms frequently used as biological indicators such as Geobacillus stearothermophilus (ATCC 7953) and Bacillus subtilis 5230 (ATCC 35021). Consequently, the majority of large-volume parenteral solutions in Japan are manufactured under low-heat sterilization conditions of F0 <2 min, so that loss of clarity of solutions and formation of degradation products of constituents are minimized. Bacillus oleronius (ATCC 700005) is listed as a biological indicator in "Guidance on the Manufacture of Sterile Pharmaceutical Products Produced by Terminal Sterilization" (guidance in Japan, issued in 2012). In this study, we investigated whether B. oleronius is an appropriate biological indicator of the efficacy of low-heat, moist-heat sterilization of large-volume parenterals. Specifically, we investigated the spore-forming ability of this microorganism in various cultivation media and measured the D-values and z-values as parameters of heat resistance. The D-values and z-values changed depending on the constituents of large-volume parenteral products. Also, the spores from B. oleronius showed a moist-heat resistance that was similar to or greater than many of the spore-forming organisms isolated from Japanese parenteral manufacturing processes. Taken together, these results indicate that B. oleronius is suitable as a biological indicator for sterility assurance of large-volume parenteral solutions subjected to low-heat, moist-heat terminal sterilization.

  13. GPU-Based 3D Cone-Beam CT Image Reconstruction for Large Data Volume

    PubMed Central

    Zhao, Xing; Hu, Jing-jing; Zhang, Peng

    2009-01-01

    Currently, 3D cone-beam CT image reconstruction speed is still a severe limitation for clinical application. The computational power of modern graphics processing units (GPUs) has been harnessed to provide impressive acceleration of 3D volume image reconstruction. For extra large data volume exceeding the physical graphic memory of GPU, a straightforward compromise is to divide data volume into blocks. Different from the conventional Octree partition method, a new partition scheme is proposed in this paper. This method divides both projection data and reconstructed image volume into subsets according to geometric symmetries in circular cone-beam projection layout, and a fast reconstruction for large data volume can be implemented by packing the subsets of projection data into the RGBA channels of GPU, performing the reconstruction chunk by chunk and combining the individual results in the end. The method is evaluated by reconstructing 3D images from computer-simulation data and real micro-CT data. Our results indicate that the GPU implementation can maintain original precision and speed up the reconstruction process by 110–120 times for circular cone-beam scan, as compared to traditional CPU implementation. PMID:19730744

  14. Array of virtual Frisch-grid CZT detectors with common cathode readout and pulse-height correction

    SciTech Connect

    Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Egarievwe, E.U.; Fochuk, P.M.; Fuerstnau, M.; Gul, R.; Hossain, A.; Jones, F.; Kim, K.; Kopach, O.V.; Taggart, R.; Yang, G.; Ye, Z.; Xu, L.; and James, R.B.

    2010-08-01

    We present our new results from testing 15-mm-long virtual Frisch-grid CdZnTe detectors with a common-cathode readout for correcting pulse-height distortions. The array employs parallelepiped-shaped CdZnTe (CZT) detectors of a large geometrical aspect ratio, with two planar contacts on the top and bottom surfaces (anode and cathode) and an additional shielding electrode on the crystal's sides to create the virtual Frisch-grid effect. We optimized the geometry of the device and improved its spectral response. We found that reducing to 5 mm the length of the shielding electrode placed next to the anode had no adverse effects on the device's performance. At the same time, this allowed corrections for electron loss by reading the cathode signals to obtain depth information.

  15. CZT pixel detectors equipped with effective Ohmic contacts; their spectroscopic performance and the enigma of why they thus behave

    NASA Astrophysics Data System (ADS)

    El-Hanany, Uri; Shahar, Allon; Tsigelman, A.

    1999-10-01

    The performance of CZT pixel detectors, with dedicated ICs and electronic processors, have been demonstrated. These nuclear imaging modules, developed primarily for the medical market, may be utilized for other applications, such as large area nuclear spectrometers. An improved crystal growth technique ensures a practical supply of wafers of which high performance detectors are fabricated. We believe that the high spectroscopic quality of these detectors stems from their effective Ohmic behavior, coupled with the geometrical, 'small pixel' effect. The Ohmic operation of these detectors has been described in a schematic way only, where the detailed non-equilibrium mechanism, responsible for it, still remains to be explained in detail. The IMARAD detector type 2, with contacts which strongly limit the dark current, exhibit even improved spectroscopic behavior, due to a dynamic Ohmic behavior of these contacts.

  16. The large volume radiometric calorimeter system: A transportable device to measure scrap category plutonium

    SciTech Connect

    Duff, M.F.; Wetzel, J.R.; Breakall, K.L.; Lemming, J.F.

    1987-01-01

    An innovative design concept has been used to design a large volume calorimeter system. The new design permits two measuring cells to fit in a compact, nonevaporative environmental bath. The system is mounted on a cart for transportability. Samples in the power range of 0.50 to 12.0 W can be measured. The calorimeters will receive samples as large as 22.0 cm in diameter by 43.2 cm high, and smaller samples can be measured without lengthening measurement time or increasing measurement error by using specially designed sleeve adapters. This paper describes the design considerations, construction, theory, applications, and performance of the large volume calorimeter system. 2 refs., 5 figs., 1 tab.

  17. Performance Characteristics of Pixelated CZT Crystals used on the GammaTracker Project

    SciTech Connect

    Becker, Eric M.; Seifert, Carolyn E.; Myjak, Mitchell J.; Erikson, Luke E.; Morris, Scott J.; Balvage, Duane R.; Lundy, Richard P.

    2011-08-21

    GammaTracker is a handheld radioisotope identification device in development at Pacific Northwest National Laboratory that uses eighteen pixelated Cadmium-Zinc Telluride (CZT) crystals to provide energy resolution approaching that of high-purity germanium without the need for cryogenic cooling. Additionally, these crystals can be used to provide directional and imaging capabilities that cannot be found in other handheld detectors. A significant number of CZT crystals have been procured during the development of the GammaTracker system; the majority of these were procured with the same set of specifications. Each of these detectors has been characterized in terms of key parameters, including current-voltage response and pixel-by-pixel energy resolution. The results of this testing indicate that the overall quality of CZT crystals is improving over time.

  18. A reference voltage in capacitor-resister hybrid SAR ADC for front-end readout system of CZT detector

    NASA Astrophysics Data System (ADS)

    Wei, Liu; Tingcun, Wei; Bo, Li; Lifeng, Yang; Yongcai, Hu

    2016-01-01

    An on-chip reference voltage has been designed in capacitor-resister hybrid SAR ADC for CZT detector with the TSMC 0.35 μm 2P4M CMOS process. The voltage reference has a dynamic load since using variable capacitors and resistances, which need a large driving ability to deal with the current related to the time and sampling rate. Most of the previous articles about the reference for ADC present only the bandgap part for a low temperature coefficient and high PSRR. However, it is not enough and overall, it needs to consider the output driving ability. The proposed voltage reference is realized by the band-gap reference, voltage generator and output buffer. Apart from a low temperature coefficient and high PSRR, it has the features of a large driving ability and low power consumption. What is more, for CZT detectors application in space, a radiation-hardened design has been considered. The measurement results show that the output reference voltage of the buffer is 4.096 V. When the temperature varied from 0 to 80 °C, the temperature coefficient is 12.2 ppm/°C. The PSRR was -70 dB @ 100 kHz. The drive current of the reference can reach up to 10 mA. The area of the voltage reference in the SAR ADC chip is only 449 × 614 μm2. The total power consumption is only 1.092 mW. Project supported by the National Key Scientific Instrument and Equipment Development Project (No. 2011YQ040082), the National Natural Science Foundation of China (No. 61376034), and the Shaanxi Province Science and Technology Innovation Project (No. 2015KTZDGY03-03).

  19. Resonators for solid-state lasers with large-volume fundamental mode and high alignment stability

    SciTech Connect

    Magni, V.

    1986-01-01

    Resonators containing a focusing rod are thoroughly analyzed. It is shown that, as a function of the dioptric power of the rod, two stability zones of the same width exist and that the mode volume in the rod always presents a stationary point. At this point, the output power is insensitive to the focal length fluctuations, and the mode volume inside the rod is inversely proportional to the range of the input power for which the resonator is stable. The two zones are markedly different with respect to misalignment sensitivity, which is, in general, much greater in one zone than in the other. Two design procedures are presented for monomode solid-state laser resonators with large mode volume and low sensitivity both to focal length fluctuations and to misalignment.

  20. Evaluation of quantitative accuracy in CZT-based pre-clinical SPECT for various isotopes

    NASA Astrophysics Data System (ADS)

    Park, S.-J.; Yu, A. R.; Kim, Y.-s.; Kang, W.-S.; Jin, S. S.; Kim, J.-S.; Son, T. J.; Kim, H.-J.

    2015-05-01

    In vivo pre-clinical single-photon emission computed tomography (SPECT) is a valuable tool for functional small animal imaging, but several physical factors, such as scatter radiation, limit the quantitative accuracy of conventional scintillation crystal-based SPECT. Semiconductor detectors such as CZT overcome these deficiencies through superior energy resolution. To our knowledge, little scientific information exists regarding the accuracy of quantitative analysis in CZT-based pre-clinical SPECT systems for different isotopes. The aim of this study was to assess the quantitative accuracy of CZT-based pre-clinical SPECT for four isotopes: 201Tl, 99mTc, 123I, and 111In. The quantitative accuracy of the CZT-based Triumph X-SPECT (Gamma-Medica Ideas, Northridge, CA, U.S.A.) was compared with that of a conventional SPECT using GATE simulation. Quantitative errors due to the attenuation and scatter effects were evaluated for all four isotopes with energy windows of 5%, 10%, and 20%. A spherical source containing the isotope was placed at the center of the air-or-water-filled mouse-sized cylinder phantom. The CZT-based pre-clinical SPECT was more accurate than the conventional SPECT. For example, in the conventional SPECT with an energy window of 10%, scatter effects degraded quantitative accuracy by up to 11.52%, 5.10%, 2.88%, and 1.84% for 201Tl, 99mTc, 123I, and 111In, respectively. However, with the CZT-based pre-clinical SPECT, the degradations were only 9.67%, 5.45%, 2.36%, and 1.24% for 201Tl, 99mTc, 123I, and 111In, respectively. As the energy window was increased, the quantitative errors increased in both SPECT systems. Additionally, the isotopes with lower energy of photon emissions had greater quantitative error. Our results demonstrated that the CZT-based pre-clinical SPECT had lower overall quantitative errors due to reduced scatter and high detection efficiency. Furthermore, the results of this systematic assessment quantifying the accuracy of these SPECT

  1. Constitutive modeling of large inelastic deformation of amorphous polymers: Free volume and shear transformation zone dynamics

    NASA Astrophysics Data System (ADS)

    Voyiadjis, George Z.; Samadi-Dooki, Aref

    2016-06-01

    Due to the lack of the long-range order in their molecular structure, amorphous polymers possess a considerable free volume content in their inter-molecular space. During finite deformation, these free volume holes serve as the potential sites for localized permanent plastic deformation inclusions which are called shear transformation zones (STZs). While the free volume content has been experimentally shown to increase during the course of plastic straining in glassy polymers, thermal analysis of stored energy due to the deformation shows that the STZ nucleation energy decreases at large plastic strains. The evolution of the free volume, and the STZs number density and nucleation energy during the finite straining are formulated in this paper in order to investigate the uniaxial post-yield softening-hardening behavior of the glassy polymers. This study shows that the reduction of the STZ nucleation energy, which is correlated with the free volume increase, brings about the post-yield primary softening of the amorphous polymers up to the steady-state strain value; and the secondary hardening is a result of the increased number density of the STZs, which is required for large plastic strains, while their nucleation energy is stabilized beyond the steady-state strain. The evolutions of the free volume content and STZ nucleation energy are also used to demonstrate the effect of the strain rate, temperature, and thermal history of the sample on its post-yield behavior. The obtained results from the model are compared with the experimental observations on poly(methyl methacrylate) which show a satisfactory consonance.

  2. Geophysics Under Pressure: Large-Volume Presses Versus the Diamond-Anvil Cell

    NASA Astrophysics Data System (ADS)

    Hazen, R. M.

    2002-05-01

    Prior to 1970, the legacy of Harvard physicist Percy Bridgman dominated high-pressure geophysics. Massive presses with large-volume devices, including piston-cylinder, opposed-anvil, and multi-anvil configurations, were widely used in both science and industry to achieve a range of crustal and upper mantle temperatures and pressures. George Kennedy of UCLA was a particularly influential advocate of large-volume apparatus for geophysical research prior to his death in 1980. The high-pressure scene began to change in 1959 with the invention of the diamond-anvil cell, which was designed simultaneously and independently by John Jamieson at the University of Chicago and Alvin Van Valkenburg at the National Bureau of Standards in Washington, DC. The compact, inexpensive diamond cell achieved record static pressures and had the advantage of optical access to the high-pressure environment. Nevertheless, members of the geophysical community, who favored the substantial sample volumes, geothermally relevant temperature range, and satisfying bulk of large-volume presses, initially viewed the diamond cell with indifference or even contempt. Several factors led to a gradual shift in emphasis from large-volume presses to diamond-anvil cells in geophysical research during the 1960s and 1970s. These factors include (1) their relatively low cost at time of fiscal restraint, (2) Alvin Van Valkenburg's new position as a Program Director at the National Science Foundation in 1964 (when George Kennedy's proposal for a Nation High-Pressure Laboratory was rejected), (3) the development of lasers and micro-analytical spectroscopic techniques suitable for analyzing samples in a diamond cell, and (4) the attainment of record pressures (e.g., 100 GPa in 1975 by Mao and Bell at the Geophysical Laboratory). Today, a more balanced collaborative approach has been adopted by the geophysics and mineral physics community. Many high-pressure laboratories operate a new generation of less expensive

  3. Assembly, operation and disassembly manual for the Battelle Large Volume Water Sampler (BLVWS)

    SciTech Connect

    Thomas, V.W.; Campbell, R.M.

    1984-12-01

    Assembly, operation and disassembly of the Battelle Large Volume Water Sampler (BLVWS) are described in detail. Step by step instructions of assembly, general operation and disassembly are provided to allow an operator completely unfamiliar with the sampler to successfully apply the BLVWS to his research sampling needs. The sampler permits concentration of both particulate and dissolved radionuclides from large volumes of ocean and fresh water. The water sample passes through a filtration section for particle removal then through sorption or ion exchange beds where species of interest are removed. The sampler components which contact the water being sampled are constructed of polyvinylchloride (PVC). The sampler has been successfully applied to many sampling needs over the past fifteen years. 9 references, 8 figures.

  4. HYBRID BRIDGMAN ANVIL DESIGN: AN OPTICAL WINDOW FOR IN-SITU SPECTROSCOPY IN LARGE VOLUME PRESSES

    SciTech Connect

    Lipp, M J; Evans, W J; Yoo, C S

    2005-07-29

    The absence of in-situ optical probes for large volume presses often limits their application to high-pressure materials research. In this paper, we present a unique anvil/optical window-design for use in large volume presses, which consists of an inverted diamond anvil seated in a Bridgman type anvil. A small cylindrical aperture through the Bridgman anvil ending at the back of diamond anvil allows optical access to the sample chamber and permits direct optical spectroscopy measurements, such as ruby fluorescence (in-situ pressure) or Raman spectroscopy. This performance of this anvil-design has been demonstrated by loading KBr to a pressure of 14.5 GPa.

  5. The large volume calorimeter for measuring the pressure cooker'' shipping container

    SciTech Connect

    Kasperski, P.W.; Duff, M.F.; Wetzel, J.R. ); Baker, L.B.; MacMurdo, K.W. )

    1991-01-01

    A precise, low wattage, large volume calorimeter system has been developed at Mound to measure two configurations of the 12081 containment vessel. This system was developed and constructed to perform verification measurements at the Savannah River Site. The calorimeter system has performance design specifications of {plus minus}0.3% error above the 2-watt level, and {plus minus}(0.03% plus 0.006 watts) at power levels below 2 watts (one sigma). Data collected during performance testing shows measurement errors well within this range, even down to 0.1-watt power levels. The development of this calorimeter shows that ultra-precise measurements can be achieved on extremely large volume sample configurations. 1 ref., 5 figs.

  6. Large-aperture chirped volume Bragg grating based fiber CPA system.

    PubMed

    Liao, Kai-Hsiu; Cheng, Ming-Yuan; Flecher, Emilie; Smirnov, Vadim I; Glebov, Leonid B; Galvanauskas, Almantas

    2007-04-16

    A fiber chirped pulse amplification system at 1558 nm was demonstrated using a large-aperture volume Bragg grating stretcher and compressor made of Photo-Thermal-Refractive (PTR) glass. Such PTR glass based gratings represent a new type of pulse stretching and compressing devices which are compact, monolithic and optically efficient. Furthermore, since PTR glass technology enables volume gratings with transverse apertures which are large, homogeneous and scalable, it also enables high pulse energies and powers far exceeding those achievable with other existing compact pulse-compression technologies. Additionally, reciprocity of chirped gratings with respect to stretching and compression also enables to address a long-standing problem in CPA system design of stretcher-compressor dispersion mismatch.

  7. Large-aperture chirped volume Bragg grating based fiber CPA system

    NASA Astrophysics Data System (ADS)

    Liao, Kai-Hsiu; Cheng, Ming-Yuan; Flecher, Emilie; Smirnov, Vadim I.; Glebov, Leonid B.; Galvanauskas, Almantas

    2007-04-01

    A fiber chirped pulse amplification system at 1558nm was demonstrated using a large-aperture volume Bragg grating stretcher and compressor made of Photo-Thermal-Refractive (PTR) glass. Such PTR glass based gratings represent a new type of pulse stretching and compressing devices which are compact, monolithic and optically efficient. Furthermore, since PTR glass technology enables volume gratings with transverse apertures which are large, homogeneous and scalable, it also enables high pulse energies and powers far exceeding those achievable with other existing compact pulse-compression technologies. Additionally, reciprocity of chirped gratings with respect to stretching and compression also enables to address a long-standing problem in CPA system design of stretcher-compressor dispersion mismatch.

  8. Technical note: rapid, large-volume resuscitation at resuscitative thoracotomy by intra-cardiac catheterization

    PubMed Central

    Cawich, Shamir O; Naraynsingh, Vijay

    2016-01-01

    An emergency thoracotomy may be life-saving by achieving four goals: (i) releasing cardiac tamponade, (ii) controlling haemorrhage, (iii) allowing access for internal cardiac massage and (iv) clamping the descending aorta to isolate circulation to the upper torso in damage control surgery. We theorize that a new goal should be achieving rapid, large-volume fluid resuscitation and we describe a technique to achieve this. PMID:27887010

  9. Rapid Adaptive Optical Recovery of Optimal Resolution over LargeVolumes

    PubMed Central

    Wang, Kai; Milkie, Dan; Saxena, Ankur; Engerer, Peter; Misgeld, Thomas; Bronner, Marianne E.; Mumm, Jeff; Betzig, Eric

    2014-01-01

    Using a de-scanned, laser-induced guide star and direct wavefront sensing, we demonstrate adaptive correction of complex optical aberrations at high numerical aperture and a 14 ms update rate. This permits us to compensate for the rapid spatial variation in aberration often encountered in biological specimens, and recover diffraction-limited imaging over large (> 240 μm)3 volumes. We applied this to image fine neuronal processes and subcellular dynamics within the zebrafish brain. PMID:24727653

  10. Scanning laser optical computed tomography system for large volume 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2017-04-01

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  11. 3D cell-printing of large-volume tissues: Application to ear regeneration.

    PubMed

    Lee, Jung-Seob; Kim, Byung Soo; Seo, Dong Hwan; Park, Jeong Hun; Cho, Dong-Woo

    2017-01-17

    The three-dimensional (3D) printing of large-volume cells, printed in a clinically relevant size, is one of the most important challenges in the field of tissue engineering. However, few studies have reported the fabrication of large-volume cell-printed constructs (LCCs). To create LCCs, appropriate fabrication conditions should be established: factors involved include fabrication time, residence time, and temperature control of the cell-laden hydrogel in the syringe to ensure high cell viability and functionality. The prolonged time required for 3D printing of LCCs can reduce cell viability and result in insufficient functionality of the construct, because the cells are exposed to a harsh environment during the printing process. In this regard, we present an advanced 3D cell-printing system composed of a clean air workstation, humidifier, and Peltier system, which provides a suitable printing environment for production of LCCs with high cell viability. We confirmed that the advanced 3D cell-printing system was capable of providing enhanced printability of hydrogels and fabricating an ear-shaped LCC with high cell viability. In vivo results for the ear-shaped LCC also showed that printed chondrocytes proliferated sufficiently and differentiated into cartilage tissue. Thus, we conclude that the advanced 3D cell-printing system is a versatile tool to create cell-printed constructs for the generation of large-volume tissues.

  12. Scanning laser optical computed tomography system for large volume 3D dosimetry.

    PubMed

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2017-04-07

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  13. Conference on physics from large gamma-ray detec tor arrays. Volume 2: Proceedings

    NASA Astrophysics Data System (ADS)

    The conference on 'Physics from Large gamma-ray Detector Arrays' is a continuation of the series of conferences that have been organized every two years by the North American Heavy-ion Laboratories. The aim of the conference this year was to encourage discussion of the physics that can be studied with such large arrays. This volume is the collected proceedings from this conference. It discusses properties of nuclear states which can be created in heavy-ion reactions, and which can be observed via such detector systems.

  14. Prospects of the search for neutrino bursts from supernovae with Baksan large volume scintillation detector

    NASA Astrophysics Data System (ADS)

    Petkov, V. B.

    2016-11-01

    Observing a high-statistics neutrino signal from the supernova explosions in the Galaxy is a major goal of low-energy neutrino astronomy. The prospects for detecting all flavors of neutrinos and antineutrinos from the core-collapse supernova (ccSN) in operating and forthcoming large liquid scintillation detectors (LLSD) are widely discussed now. One of proposed LLSD is Baksan Large Volume Scintillation Detector (BLVSD). This detector will be installed at the Baksan Neutrino Observatory (BNO) of the Institute for Nuclear Research, Russian Academy of Sciences, at a depth of 4800 m.w.e. Low-energy neutrino astronomy is one of the main lines of research of the BLVSD.

  15. Large-volume paracentesis with indwelling peritoneal catheter and albumin infusion: a community hospital study

    PubMed Central

    Martin, Daniel K.; Walayat, Saqib; Jinma, Ren; Ahmed, Zohair; Ragunathan, Karthik; Dhillon, Sonu

    2016-01-01

    Background The management of ascites can be problematic. This is especially true in patients with diuretic refractory ascites who develop a tense abdomen. This often results in hypotension and decreased venous return with resulting renal failure. In this paper, we further examine the risks and benefits of utilizing an indwelling peritoneal catheter to remove large-volume ascites over a 72-h period while maintaining intravascular volume and preventing renal failure. Methods We retrospectively reviewed charts and identified 36 consecutive patients undergoing continuous large-volume paracentesis with an indwelling peritoneal catheter. At the time of drain placement, no patients had signs or laboratory parameters suggestive of spontaneous bacterial peritonitis. The patients underwent ascitic fluid removal through an indwelling peritoneal catheter and were supported with scheduled albumin throughout the duration. The catheter was used to remove up to 3 L every 8 h for a maximum of 72 h. Regular laboratory and ascitic fluid testing was performed. All patients had a clinical follow-up within 3 months after the drain placement. Results An average of 16.5 L was removed over the 72-h time frame of indwelling peritoneal catheter maintenance. The albumin infusion utilized correlated to 12 mg/L removed. The average creatinine trend improved in a statistically significant manner from 1.37 on the day of admission to 1.21 on the day of drain removal. No patients developed renal failure during the hospital course. There were no documented episodes of neutrocytic ascites or bacterial peritonitis throughout the study review. Conclusion Large-volume peritoneal drainage with an indwelling peritoneal catheter is safe and effective for patients with tense ascites. Concomitant albumin infusion allows for maintenance of renal function, and no increase in infectious complications was noted. PMID:27802853

  16. CZT detector for dual-energy x-ray absorptiometry (DEXA)

    NASA Astrophysics Data System (ADS)

    Wear, James; Buchholz, Michael; Payne, Randall K.; Gorsuch, Darrell; Bisek, Joseph; Ergun, David L.; Grosholz, Joe; Falk, Ron

    2000-12-01

    A cadmium-zinc-telluride (CZT) detector has been developed for a bone densitometer that uses dual-energy x-ray absorptiometry (DEXA) to determine bone mineral density in vivo. A linear array of 16 discrete CZT detectors is used with a narrow fan-shaped x-ray beam to scan the patient. Each detector is 3 mm thick and 7 mm by 3 mm in area and has simple planar contacts. The x-ray beam has two broad energy lobes with effective energies of approximately 38 keV and approximately 65 keV. The energy sensitivity of the CZT detectors allows discrimination between low and high energy x-rays. Using DEXA, the relative difference in these two count rates permits a quantitative measurement of the real densities of bone mineral and soft tissue. The detectors demonstrate good performance characteristics and stable operation in a clinical environment. This paper discusses the suitability of CZT for use in DEXA applications and describes its successful implementation and performance in this bone densitometer.

  17. Mechanically Cooled Large-Volume Germanium Detector Systems for Neclear Explosion Monitoring DOENA27323-2

    SciTech Connect

    Hull, E.L.

    2006-10-30

    Compact maintenance free mechanical cooling systems are being developed to operate large volume high-resolution gamma-ray detectors for field applications. To accomplish this we are utilizing a newly available generation of Stirling-cycle mechanical coolers to operate the very largest volume germanium detectors with no maintenance. The user will be able to leave these systems unplugged on the shelf until needed. The maintenance-free operating lifetime of these detector systems will exceed 5 years. Three important factors affect the operation of mechanically cooled germanium detectors: temperature, vacuum, and vibration. These factors will be studied in the laboratory at the most fundamental levels to insure a solid understanding of the physical limitations each factor places on a practical mechanically cooled germanium detector system. Using this knowledge, mechanically cooled germanium detector prototype systems will be designed and fabricated.

  18. The complex aerodynamic footprint of desert locusts revealed by large-volume tomographic particle image velocimetry.

    PubMed

    Henningsson, Per; Michaelis, Dirk; Nakata, Toshiyuki; Schanz, Daniel; Geisler, Reinhard; Schröder, Andreas; Bomphrey, Richard J

    2015-07-06

    Particle image velocimetry has been the preferred experimental technique with which to study the aerodynamics of animal flight for over a decade. In that time, hardware has become more accessible and the software has progressed from the acquisition of planes through the flow field to the reconstruction of small volumetric measurements. Until now, it has not been possible to capture large volumes that incorporate the full wavelength of the aerodynamic track left behind during a complete wingbeat cycle. Here, we use a unique apparatus to acquire the first instantaneous wake volume of a flying animal's entire wingbeat. We confirm the presence of wake deformation behind desert locusts and quantify the effect of that deformation on estimates of aerodynamic force and the efficiency of lift generation. We present previously undescribed vortex wake phenomena, including entrainment around the wing-tip vortices of a set of secondary vortices borne of Kelvin-Helmholtz instability in the shear layer behind the flapping wings.

  19. Non-contact spectroscopic determination of large blood volume fractions in turbid media

    PubMed Central

    Bremmer, Rolf H.; Kanick, Stephen C.; Laan, Nick; Amelink, Arjen; van Leeuwen, Ton G.; Aalders, Maurice C. G.

    2011-01-01

    We report on a non-contact method to quantitatively determine blood volume fractions in turbid media by reflectance spectroscopy in the VIS/NIR spectral wavelength range. This method will be used for spectral analysis of tissue with large absorption coefficients and assist in age determination of bruises and bloodstains. First, a phantom set was constructed to determine the effective photon path length as a function of μa and μs′ on phantoms with an albedo range: 0.02-0.99. Based on these measurements, an empirical model of the path length was established for phantoms with an albedo > 0.1. Next, this model was validated on whole blood mimicking phantoms, to determine the blood volume fractions ρ = 0.12-0.84 within the phantoms (r = 0.993; error < 10%). Finally, the model was proved applicable on cotton fabric phantoms. PMID:21339884

  20. The use of digital volume tomography in imaging an unusually large composite odontoma in the mandible.

    PubMed

    Bhatavadekar, Neel B; Bouquot, Jerry E

    2009-01-01

    The odontoma is the most common of all odontogenic tumors. Digital volume tomography (DVT) provides a major advantage of decreased radiation and cost-effectiveness, as compared to a conventional computed tomography. There is no known published report utilizing this DVT analysis for assessing and localizing on odontomo. The purpose of this case report was to document the use of digital volume tomography to assess an unusually large composite odontoma in the mondible. Tomographic sections revealed expansion of the buccol cortex and occasional thinning of both the buccol and lingual cortical plates, although there was no pronounced clinically detectable cortical expansion. The sections further demonstrated enomel ond dentin in on irregular mass bearing no morphologic similority to rudimentary teeth. This case highlights the importance of early diagnosis and intervention for treating on odontoma while demonstrating the value of tomographic imaging as on aid to diagnosis.

  1. The complex aerodynamic footprint of desert locusts revealed by large-volume tomographic particle image velocimetry

    PubMed Central

    Henningsson, Per; Michaelis, Dirk; Nakata, Toshiyuki; Schanz, Daniel; Geisler, Reinhard; Schröder, Andreas; Bomphrey, Richard J.

    2015-01-01

    Particle image velocimetry has been the preferred experimental technique with which to study the aerodynamics of animal flight for over a decade. In that time, hardware has become more accessible and the software has progressed from the acquisition of planes through the flow field to the reconstruction of small volumetric measurements. Until now, it has not been possible to capture large volumes that incorporate the full wavelength of the aerodynamic track left behind during a complete wingbeat cycle. Here, we use a unique apparatus to acquire the first instantaneous wake volume of a flying animal's entire wingbeat. We confirm the presence of wake deformation behind desert locusts and quantify the effect of that deformation on estimates of aerodynamic force and the efficiency of lift generation. We present previously undescribed vortex wake phenomena, including entrainment around the wing-tip vortices of a set of secondary vortices borne of Kelvin–Helmholtz instability in the shear layer behind the flapping wings. PMID:26040598

  2. Very Large Area/Volume Microwave ECR Plasma and Ion Source

    NASA Technical Reports Server (NTRS)

    Foster, John E. (Inventor); Patterson, Michael J. (Inventor)

    2009-01-01

    The present invention is an apparatus and method for producing very large area and large volume plasmas. The invention utilizes electron cyclotron resonances in conjunction with permanent magnets to produce dense, uniform plasmas for long life ion thruster applications or for plasma processing applications such as etching, deposition, ion milling and ion implantation. The large area source is at least five times larger than the 12-inch wafers being processed to date. Its rectangular shape makes it easier to accommodate to materials processing than sources that are circular in shape. The source itself represents the largest ECR ion source built to date. It is electrodeless and does not utilize electromagnets to generate the ECR magnetic circuit, nor does it make use of windows.

  3. A volume law for specification of linear channel storage for estimation of large floods

    NASA Astrophysics Data System (ADS)

    Zhang, Shangyou; Cordery, Ian; Sharma, Ashish

    2000-02-01

    A method of estimating large floods using a linear storage-routing approach is presented. The differences between the proposed approach and those traditionally used are (1) that the flood producing properties of basins are represented by a linear system, (2) the storage parameters of the distributed model are determined using a volume law which, unlike other storage-routing models, accounts for the distribution of storage in natural basins, and (3) the basin outflow hydrograph is determined analytically and expressed in a succinct mathematical form. The single model parameter is estimated from observed data without direct fitting, unlike most traditionally used methods. The model was tested by showing it could reproduce observed large floods on a number of basins. This paper compares the proposed approach with a traditionally used storage routing approach using observed flood data from the Hacking River basin in New South Wales, Australia. Results confirm the usefulness of the proposed approach for estimation of large floods.

  4. Two-field Kaehler moduli inflation in large volume moduli stabilization

    SciTech Connect

    Yang, Huan-Xiong; Ma, Hong-Liang E-mail: hlma@mail.ustc.edu.cn

    2008-08-15

    In this paper we present a two-field inflation model, which is distinctive in having a non-canonical kinetic Lagrangian and comes from the large volume approach to the moduli stabilization in flux compactification of type IIB superstring on a Calabi-Yau orientifold with h{sup (1,2)}>h{sup (1,1)}{>=}4. The Kaehler moduli are classified as the volume modulus, heavy moduli and two light moduli. The axion-dilaton, complex structure moduli and all heavy Kaehler moduli including the volume modulus are frozen by a non-perturbatively corrected flux superpotential and the {alpha}{sup '}-corrected Kaehler potential in the large volume limit. The minimum of the scalar potential at which the heavy moduli are stabilized provides the dominant potential energy for the surviving light Kaehler moduli. We consider a simplified case where the axionic components in the light Kaehler moduli are further stabilized at the potential minimum and only the geometrical components are taken as scalar fields to drive an assisted-like inflation. For a certain range of moduli stabilization parameters and inflation initial conditions, we obtain a nearly flat power spectrum of the curvature perturbation, with n{sub s} Almost-Equal-To 0.96 at Hubble exit, and an inflationary energy scale of 3 Multiplication-Sign 10{sup 14} GeV. In our model, there is significant correlation between the curvature and isocurvature perturbations on super-Hubble scales, so at the end of inflation a great deal of the curvature power spectrum originates from this correlation.

  5. Evaluation of a photon counting Medipix3RX CZT spectral x-ray detector

    PubMed Central

    Jorgensen, Steven M.; Vercnocke, Andrew J.; Rundle, David S.; Butler, Philip H.; McCollough, Cynthia H.; Ritman, Erik L.

    2016-01-01

    We assessed the performance of a cadmium zinc telluride (CZT)-based Medipix3RX x-ray detector as a candidate for micro-computed tomography (micro-CT) imaging. This technology was developed at CERN for the Large Hadron Collider. It features an array of 128 by 128, 110 micrometer square pixels, each with eight simultaneous threshold counters, five of which utilize real-time charge summing, significantly reducing the charge sharing between contiguous pixels. Pixel response curves were created by imaging a range of x-ray intensities by varying x-ray tube current and by varying the exposure time with fixed x-ray current. Photon energy-related assessments were made by flooding the detector with the tin foil filtered emission of an I-125 radioisotope brachytherapy seed and sweeping the energy threshold of each of the four charge-summed counters of each pixel in 1 keV steps. Long term stability assessments were made by repeating exposures over the course of one hour. The high properly-functioning pixel yield (99%), long term stability (linear regression of whole-chip response over one hour of acquisitions: y = −0.0038x + 2284; standard deviation: 3.7 counts) and energy resolution (2.5 keV FWHM (single pixel), 3.7 keV FWHM across the full image) make this device suitable for spectral micro-CT. The charge summing performance effectively reduced the measurement corruption caused by charge sharing which, when unaccounted for, shifts the photon energy assignment to lower energies, degrading both count and energy accuracy. Effective charge summing greatly improves the potential for calibrated, energy-specific material decomposition and K edge difference imaging approaches. PMID:27795606

  6. Evaluation of a photon counting Medipix3RX CZT spectral x-ray detector

    NASA Astrophysics Data System (ADS)

    Jorgensen, Steven M.; Vercnocke, Andrew J.; Rundle, David S.; Butler, Philip H.; McCollough, Cynthia H.; Ritman, Erik L.

    2016-10-01

    We assessed the performance of a cadmium zinc telluride (CZT)-based Medipix3RX x-ray detector as a candidate for micro-computed tomography (micro-CT) imaging. This technology was developed at CERN for the Large Hadron Collider. It features an array of 128 by 128, 110 micrometer square pixels, each with eight simultaneous threshold counters, five of which utilize real-time charge summing, significantly reducing the charge sharing between contiguous pixels. Pixel response curves were created by imaging a range of x-ray intensities by varying x-ray tube current and by varying the exposure time with fixed x-ray current. Photon energy-related assessments were made by flooding the detector with the tin foil filtered emission of an I-125 radioisotope brachytherapy seed and sweeping the energy threshold of each of the four charge-summed counters of each pixel in 1 keV steps. Long term stability assessments were made by repeating exposures over the course of one hour. The high properly-functioning pixel yield (99%), long term stability (linear regression of whole-chip response over one hour of acquisitions: y = -0.0038x + 2284; standard deviation: 3.7 counts) and energy resolution (2.5 keV FWHM (single pixel), 3.7 keV FWHM across the full image) make this device suitable for spectral micro-CT. The charge summing performance effectively reduced the measurement corruption caused by charge sharing which, when unaccounted for, shifts the photon energy assignment to lower energies, degrading both count and energy accuracy. Effective charge summing greatly improves the potential for calibrated, energy-specific material decomposition and K edge difference imaging approaches.

  7. Study of electrode pattern design for a CZT-based PET detector

    PubMed Central

    Gu, Y; Levin, C S

    2014-01-01

    We are developing a 1 mm resolution small animal positron emission tomography (PET) system using 3-D positioning Cadmium Zinc Telluride (CZT) photon detectors comprising 40 mm × 40 mm × 5 mm crystals metalized with a cross-strip electrode pattern with a 1 mm anode strip pitch. We optimized the electrode pattern design for intrinsic sensitivity and spatial, energy and time resolution performance using a test detector comprising cathode and steering electrode strips of varying dimensions. The study found 3 mm and 5 mm width cathode strips locate charge-shared photon interactions near cathode strip boundaries with equal precision. 3 mm width cathode strips exhibited large time resolution variability as a function of photon interaction location between the anode and cathode planes (~26 ns to ~127.5 ns FWHM for 0.5 mm and 4.2 mm depths, respectively). 5 mm width cathode strips by contrast exhibited more stable time resolution for the same interaction locations (~34 ns to ~83 ns FWHM), provided more linear spatial positioning in the direction orthogonal to the electrode planes, and as much as 68.4% improvement in photon sensitivity over the 3 mm wide cathode strips. The results were understood by analyzing the cathode strips’ weighting functions, which indicated a stronger “small pixel” effect in the 3 mm wide cathode strips. Photon sensitivity and anode energy resolution were seen to improve with decreasing steering electrode bias from 0 V to −80 V w.r.t the anode potential. A slight improvement in energy resolution was seen for wider steering electrode strips (400 μm vs. 100 μm) for charge-shared photon interactions. Although this study successfully focused on electrode pattern features for PET performance, the results are generally applicable to semiconductor photon detectors employing cross-trip electrode patterns. PMID:24786208

  8. A Novel Technique for Endovascular Removal of Large Volume Right Atrial Tumor Thrombus.

    PubMed

    Nickel, Barbara; McClure, Timothy; Moriarty, John

    2015-08-01

    Venous thromboembolic disease is a significant cause of morbidity and mortality, particularly in the setting of large volume pulmonary embolism. Thrombolytic therapy has been shown to be a successful treatment modality; however, its use somewhat limited due to the risk of hemorrhage and potential for distal embolization in the setting of large mobile thrombi. In patients where either thrombolysis is contraindicated or unsuccessful, and conventional therapies prove inadequate, surgical thrombectomy may be considered. We present a case of percutaneous endovascular extraction of a large mobile mass extending from the inferior vena cava into the right atrium using the Angiovac device, a venovenous bypass system designed for high-volume aspiration of undesired endovascular material. Standard endovascular methods for removal of cancer-associated thrombus, such as catheter-directed lysis, maceration, and exclusion, may prove inadequate in the setting of underlying tumor thrombus. Where conventional endovascular methods either fail or are unsuitable, endovascular thrombectomy with the Angiovac device may be a useful and safe minimally invasive alternative to open resection.

  9. A Novel Technique for Endovascular Removal of Large Volume Right Atrial Tumor Thrombus

    SciTech Connect

    Nickel, Barbara; McClure, Timothy Moriarty, John

    2015-08-15

    Venous thromboembolic disease is a significant cause of morbidity and mortality, particularly in the setting of large volume pulmonary embolism. Thrombolytic therapy has been shown to be a successful treatment modality; however, its use somewhat limited due to the risk of hemorrhage and potential for distal embolization in the setting of large mobile thrombi. In patients where either thrombolysis is contraindicated or unsuccessful, and conventional therapies prove inadequate, surgical thrombectomy may be considered. We present a case of percutaneous endovascular extraction of a large mobile mass extending from the inferior vena cava into the right atrium using the Angiovac device, a venovenous bypass system designed for high-volume aspiration of undesired endovascular material. Standard endovascular methods for removal of cancer-associated thrombus, such as catheter-directed lysis, maceration, and exclusion, may prove inadequate in the setting of underlying tumor thrombus. Where conventional endovascular methods either fail or are unsuitable, endovascular thrombectomy with the Angiovac device may be a useful and safe minimally invasive alternative to open resection.

  10. Cryogenic loading of large volume presses for high-pressure experimentation and synthesis of novel materials

    SciTech Connect

    Lipp, M J; Evans, W J; Yoo, C S

    2005-01-21

    We present an efficient easily implemented method for loading cryogenic fluids in a large volume press. We specifically apply this method to the high-pressure synthesis of an extended solid derived from CO using a Paris-Edinburgh cell. This method employs cryogenic cooling of Bridgman type WC anvils well insulated from other press components, condensation of the load gas within a brass annulus surrounding the gasket between the Bridgman anvils. We demonstrate the viability of the described approach by synthesizing macroscopic amounts (several milligrams) of polymeric CO-derived material, which were recovered to ambient conditions after compression of pure CO to 5 GPa or above.

  11. Incarceration of umbilical hernia: a rare complication of large volume paracentesis.

    PubMed

    Khodarahmi, Iman; Shahid, Muhammad Usman; Contractor, Sohail

    2015-09-01

    We present two cases of umbilical hernia incarceration following large volume paracentesis (LVP) in patients with cirrhotic ascites. Both patients became symptomatic within 48 hours after the LVP. Although being rare, given the significantly higher mortality rate of cirrhotic patients undergoing emergent herniorrhaphy, this complication of LVP is potentially serious. Therefore, it is recommended that patients be examined closely for the presence of umbilical hernias before removal of ascitic fluid and an attempt should be made for external reduction of easily reducible hernias, if a hernia is present.

  12. Capillary gas chromatographic analysis of nerve agents using large volume injections.

    PubMed

    Degenhardt-Langelaan, C E; Kientz, C E

    1996-02-02

    The use of large volume injections has been studied for the verification of intact organophosphorus chemical warfare agents in water samples. As the use of ethyl acetate caused severe detection problems new potential solvents were evaluated. With the developed procedure, the nerve agents sarin, tabun, soman, DFP and VX can be determined in freshly prepared water samples at ppt levels. Except for the nerve agent tabun all other agents added to the water samples were still present after 8 days at 20-60% levels, if the pH of the water sample is adjusted to ca. 5 shortly after sampling and adjusted to pH 7 for analysis.

  13. Incarceration of umbilical hernia: a rare complication of large volume paracentesis

    PubMed Central

    Khodarahmi, Iman; Shahid, Muhammad Usman; Contractor, Sohail

    2015-01-01

    We present two cases of umbilical hernia incarceration following large volume paracentesis (LVP) in patients with cirrhotic ascites. Both patients became symptomatic within 48 hours after the LVP. Although being rare, given the significantly higher mortality rate of cirrhotic patients undergoing emergent herniorrhaphy, this complication of LVP is potentially serious. Therefore, it is recommended that patients be examined closely for the presence of umbilical hernias before removal of ascitic fluid and an attempt should be made for external reduction of easily reducible hernias, if a hernia is present. PMID:26629305

  14. Large Volume, Optical and Opto-Mechanical Metrology Techniques for ISIM on JWST

    NASA Technical Reports Server (NTRS)

    Hadjimichael, Theo

    2015-01-01

    The final, flight build of the Integrated Science Instrument Module (ISIM) element of the James Webb Space Telescope is the culmination of years of work across many disciplines and partners. This paper covers the large volume, ambient, optical and opto-mechanical metrology techniques used to verify the mechanical integration of the flight instruments in ISIM, including optical pupil alignment. We present an overview of ISIM's integration and test program, which is in progress, with an emphasis on alignment and optical performance verification. This work is performed at NASA Goddard Space Flight Center, in close collaboration with the European Space Agency, the Canadian Space Agency, and the Mid-Infrared Instrument European Consortium.

  15. GMP Cryopreservation of Large Volumes of Cells for Regenerative Medicine: Active Control of the Freezing Process

    PubMed Central

    Massie, Isobel; Selden, Clare; Hodgson, Humphrey; Gibbons, Stephanie; Morris, G. John

    2014-01-01

    Cryopreservation protocols are increasingly required in regenerative medicine applications but must deliver functional products at clinical scale and comply with Good Manufacturing Process (GMP). While GMP cryopreservation is achievable on a small scale using a Stirling cryocooler-based controlled rate freezer (CRF) (EF600), successful large-scale GMP cryopreservation is more challenging due to heat transfer issues and control of ice nucleation, both complex events that impact success. We have developed a large-scale cryocooler-based CRF (VIA Freeze) that can process larger volumes and have evaluated it using alginate-encapsulated liver cell (HepG2) spheroids (ELS). It is anticipated that ELS will comprise the cellular component of a bioartificial liver and will be required in volumes of ∼2 L for clinical use. Sample temperatures and Stirling cryocooler power consumption was recorded throughout cooling runs for both small (500 μL) and large (200 mL) volume samples. ELS recoveries were assessed using viability (FDA/PI staining with image analysis), cell number (nuclei count), and function (protein secretion), along with cryoscanning electron microscopy and freeze substitution techniques to identify possible injury mechanisms. Slow cooling profiles were successfully applied to samples in both the EF600 and the VIA Freeze, and a number of cooling and warming profiles were evaluated. An optimized cooling protocol with a nonlinear cooling profile from ice nucleation to −60°C was implemented in both the EF600 and VIA Freeze. In the VIA Freeze the nucleation of ice is detected by the control software, allowing both noninvasive detection of the nucleation event for quality control purposes and the potential to modify the cooling profile following ice nucleation in an active manner. When processing 200 mL of ELS in the VIA Freeze—viabilities at 93.4%±7.4%, viable cell numbers at 14.3±1.7 million nuclei/mL alginate, and protein secretion at 10.5±1.7

  16. Alginate Hydrogel Microencapsulation Inhibits Devitrification and Enables Large-Volume Low-CPA Cell Vitrification.

    PubMed

    Huang, Haishui; Choi, Jung Kyu; Rao, Wei; Zhao, Shuting; Agarwal, Pranay; Zhao, Gang; He, Xiaoming

    2015-11-25

    Cryopreservation of stem cells is important to meet their ever-increasing demand by the burgeoning cell-based medicine. The conventional slow freezing for stem cell cryopreservation suffers from inevitable cell injury associated with ice formation and the vitrification (i.e., no visible ice formation) approach is emerging as a new strategy for cell cryopreservation. A major challenge to cell vitrification is intracellular ice formation (IIF, a lethal event to cells) induced by devitrification (i.e., formation of visible ice in previously vitrified solution) during warming the vitrified cells at cryogenic temperature back to super-zero temperatures. Consequently, high and toxic concentrations of penetrating cryoprotectants (i.e., high CPAs, up to ~8 M) and/or limited sample volumes (up to ~2.5 μl) have been used to minimize IIF during vitrification. We reveal that alginate hydrogel microencapsulation can effectively inhibit devitrification during warming. Our data show that if ice formation were minimized during cooling, IIF is negligible in alginate hydrogel-microencapsulated cells during the entire cooling and warming procedure of vitrification. This enables vitrification of pluripotent and multipotent stem cells with up to ~4 times lower concentration of penetrating CPAs (up to 2 M, low CPA) in up to ~100 times larger sample volume (up to ~250 μl, large volume).

  17. A scale down process for the development of large volume cryopreservation☆

    PubMed Central

    Kilbride, Peter; Morris, G. John; Milne, Stuart; Fuller, Barry; Skepper, Jeremy; Selden, Clare

    2014-01-01

    The process of ice formation and propagation during cryopreservation impacts on the post-thaw outcome for a sample. Two processes, either network solidification or progressive solidification, can dominate the water–ice phase transition with network solidification typically present in small sample cryo-straws or cryo-vials. Progressive solidification is more often observed in larger volumes or environmental freezing. These different ice phase progressions could have a significant impact on cryopreservation in scale-up and larger volume cryo-banking protocols necessitating their study when considering cell therapy applications. This study determines the impact of these different processes on alginate encapsulated liver spheroids (ELS) as a model system during cryopreservation, and develops a method to replicate these differences in an economical manner. It was found in the current studies that progressive solidification resulted in fewer, but proportionally more viable cells 24 h post-thaw compared with network solidification. The differences between the groups diminished at later time points post-thaw as cells recovered the ability to undertake cell division, with no statistically significant differences seen by either 48 h or 72 h in recovery cultures. Thus progressive solidification itself should not prove a significant hurdle in the search for successful cryopreservation in large volumes. However, some small but significant differences were noted in total viable cell recoveries and functional assessments between samples cooled with either progressive or network solidification, and these require further investigation. PMID:25219980

  18. Alginate Hydrogel Microencapsulation Inhibits Devitrification and Enables Large-Volume Low-CPA Cell Vitrification

    PubMed Central

    Huang, Haishui; Choi, Jung Kyu; Rao, Wei; Zhao, Shuting; Agarwal, Pranay; Zhao, Gang

    2015-01-01

    Cryopreservation of stem cells is important to meet their ever-increasing demand by the burgeoning cell-based medicine. The conventional slow freezing for stem cell cryopreservation suffers from inevitable cell injury associated with ice formation and the vitrification (i.e., no visible ice formation) approach is emerging as a new strategy for cell cryopreservation. A major challenge to cell vitrification is intracellular ice formation (IIF, a lethal event to cells) induced by devitrification (i.e., formation of visible ice in previously vitrified solution) during warming the vitrified cells at cryogenic temperature back to super-zero temperatures. Consequently, high and toxic concentrations of penetrating cryoprotectants (i.e., high CPAs, up to ~8 M) and/or limited sample volumes (up to ~2.5 μl) have been used to minimize IIF during vitrification. We reveal that alginate hydrogel microencapsulation can effectively inhibit devitrification during warming. Our data show that if ice formation were minimized during cooling, IIF is negligible in alginate hydrogel-microencapsulated cells during the entire cooling and warming procedure of vitrification. This enables vitrification of pluripotent and multipotent stem cells with up to ~4 times lower concentration of penetrating CPAs (up to 2 M, low CPA) in up to ~100 times larger sample volume (up to ~250 μl, large volume). PMID:26640426

  19. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-06-14

    This work studies the performance and scalability characteristics of"hybrid" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  20. MPI-hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-03-20

    This work studies the performance and scalability characteristics of"hybrid'" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  1. Effectiveness of nuclear interceptors against large single volume chemical/biological warheads

    SciTech Connect

    Mendelsohn, E.

    1993-01-01

    In a continuing series of calculations which explore potential nuclear defenses against chemical and/or bacteriological warheads the author has now completed a study in which he postulated a large canister geometry. Instead of looking at a collection of smaller submunitions as done previously, he has now one single large volume of Sarin (a nerve agent). This is a more stressing case for nuclear defense, in that neutrons must traverse a long path in the hydrogenous solution if they are to deposit their energy in the region of Sarin farthest from the source. The author presents results from Monte Carlo calculations which indicate that differences in energy deposition between Sarin regions close to the source and those farthest from the source have increased very significantly.

  2. Hybrid Parallelism for Volume Rendering on Large, Multi- and Many-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2011-01-01

    With the computing industry trending towards multi- and many-core processors, we study how a standard visualization algorithm, ray-casting volume rendering, can benefit from a hybrid parallelism approach. Hybrid parallelism provides the best of both worlds: using distributed-memory parallelism across a large numbers of nodes increases available FLOPs and memory, while exploiting shared-memory parallelism among the cores within each node ensures that each node performs its portion of the larger calculation as efficiently as possible. We demonstrate results from weak and strong scaling studies, at levels of concurrency ranging up to 216,000, and with datasets as large as 12.2 trillion cells. The greatest benefit from hybrid parallelism lies in the communication portion of the algorithm, the dominant cost at higher levels of concurrency. We show that reducing the number of participants with a hybrid approach significantly improves performance.

  3. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    NASA Astrophysics Data System (ADS)

    Howison, M.; Bethel, E. W.; Childs, H.

    2011-10-01

    This work studies the performance and scalability characteristics of "hybrid" parallel programming and execution as applied to raycasting volume rendering - a staple visualization algorithm - on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today, as well as processors capable of running hundreds of concurrent threads (GPUs), we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  4. Large volume leukapheresis maximizes the progenitor cell yield for allogeneic peripheral blood progenitor donation.

    PubMed

    Kobbe, G; Soehngen, D; Heyll, A; Fischer, J; Thiele, K P; Aul, C; Wernet, P

    1997-04-01

    We have investigated the efficiency and safety of large volume leukapheresis (LVL) for the collection of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPCs) from healthy donors. In six apheresis sessions in four healthy individuals on a COBE-BCT Spectra cell separator (median processed volume 3.5 X total blood volume, TBV, range 3.3-4.4 X TBV), harvested cells were collected sequentially into three single bags. The collection bags were changed after processing 33%, 66%, and 100% of the prospective apheresis volume, allowing analysis of PBPCs collected at different periods during one harvest. Mononuclear cells (MNCs), CD34+ cells, CD34+ subsets, and lymphocyte subsets were determined in each bag. Substantially more PBPCs were harvested than were in the circulation before G-CSF administration preceding LVL (median 171%, range 69-267%), reflecting progenitor release during the procedure. In donors 1 and 3, the CD34+ cell yields decreased in the third bag to 53% and 42% of that collected in the first bag, whereas the progenitor cell yields in donors 2 and 4 were stable or rose during the procedure, achieving in the third bag 157% and 105% of the number of CD34+ cells collected in the first bag. Minor changes were found in the subsets of CD34+ cells, lymphocytes, and monocytes collected at different periods during a single harvest. LVL was well tolerated. Reversible thombocytopenia developed in all cases. No late effects attributable to LVL or G-CSF were found in the 4 donors and 16 other healthy individuals who have undergone LVL in our institution. We conclude that LVL is safe and maximizes PBPC yields for allogeneic transplantation.

  5. Mechanically Cooled Large-Volume Germanium Detector Systems for Nuclear Explosion Monitoring

    SciTech Connect

    Hull, Ethan L.; Pehl, Richard H.; Lathrop, James R.; Martin, Gregory N.; Mashburn, R. B.; Miley, Harry S.; Aalseth, Craig E.; Hossbach, Todd W.; Bowyer, Ted W.

    2006-09-21

    Compact maintenance free mechanical cooling systems are being developed to operate large volume (~570 cm3, ~3 kg, 140% or larger) germanium detectors for field applications. We are using a new generation of Stirling-cycle mechanical coolers for operating the very largest volume germanium detectors with absolutely no maintenance or liquid nitrogen requirements. The user will be able to leave these systems unplugged on the shelf until needed. The flip of a switch will bring a system to life in ~1 hour for measurements. The maintenance-free operating lifetime of these detector systems will exceed five years. These features are necessary for remote long-duration liquid-nitrogen free deployment of large-volume germanium gamma-ray detector systems for Nuclear Explosion Monitoring (NEM). The Radionuclide Aerosol Sampler/Analyzer (RASA) will greatly benefit from the availability of such detectors by eliminating the need for liquid nitrogen at RASA sites while still allowing the very largest available germanium detectors to be utilized. These mechanically cooled germanium detector systems being developed here will provide the largest, most sensitive detectors possible for use with the RASA. To provide such systems, the appropriate technical fundamentals are being researched. Mechanical cooling of germanium detectors has historically been a difficult endeavor. The success or failure of mechanically cooled germanium detectors stems from three main technical issues: temperature, vacuum, and vibration. These factors affect one another. There is a particularly crucial relationship between vacuum and temperature. These factors will be experimentally studied both separately and together to insure a solid understanding of the physical limitations each factor places on a practical mechanically cooled germanium detector system for field use. Using this knowledge, a series of mechanically cooled germanium detector prototype systems are being designed and fabricated. Our collaborators

  6. Geochemical correlation of three large-volume ignimbrites from the Yellowstone hotspot track, Idaho, USA

    NASA Astrophysics Data System (ADS)

    Ellis, Ben S.; Branney, M. J.; Barry, T. L.; Barfod, D.; Bindeman, I.; Wolff, J. A.; Bonnichsen, B.

    2012-01-01

    Three voluminous rhyolitic ignimbrites have been identified along the southern margin of the central Snake River Plain. As a result of wide-scale correlations, new volume estimates can be made for these deposits: ~350 km3 for the Steer Basin Tuff and Cougar Point Tuff XI, and ~1,000 km3 for Cougar Point Tuff XIII. These volumes exclude any associated regional ashfalls and correlation across to the north side of the plain, which has yet to be attempted. Each correlation was achieved using a combination of methods including field logging, whole rock and mineral chemistry, magnetic polarity, oxygen isotope signature and high-precision 40Ar/39Ar geochronology. The Steer Basin Tuff, Cougar Point Tuff XI and Cougar Point Tuff XIII have deposit characteristics typical of `Snake River (SR)-type' volcanism: they are very dense, intensely welded and rheomorphic, unusually well sorted with scarce pumice and lithic lapilli. These features differ significantly from those of deposits from the better-known younger eruptions of Yellowstone. The ignimbrites also exhibit marked depletion in δ18O, which is known to characterise the SR-type rhyolites of the central Snake River Plain, and cumulatively represent ~1,700 km3 of low δ18O rhyolitic magma (feldspar values 2.3-2.9‰) erupted within 800,000 years. Our work reduces the total number of ignimbrites recognised in the central Snake River Plain by 6, improves the link with the ashfall record of Yellowstone hotspot volcanism and suggests that more large-volume ignimbrites await discovery through detailed correlation work amidst the vast ignimbrite record of volcanism in this bimodal large igneous province.

  7. Development of large volume double ring penning plasma discharge source for efficient light emissions.

    PubMed

    Prakash, Ram; Vyas, Gheesa Lal; Jain, Jalaj; Prajapati, Jitendra; Pal, Udit Narayan; Chowdhuri, Malay Bikas; Manchanda, Ranjana

    2012-12-01

    In this paper, the development of large volume double ring Penning plasma discharge source for efficient light emissions is reported. The developed Penning discharge source consists of two cylindrical end cathodes of stainless steel having radius 6 cm and a gap 5.5 cm between them, which are fitted in the top and bottom flanges of the vacuum chamber. Two stainless steel anode rings with thickness 0.4 cm and inner diameters 6.45 cm having separation 2 cm are kept at the discharge centre. Neodymium (Nd(2)Fe(14)B) permanent magnets are physically inserted behind the cathodes for producing nearly uniform magnetic field of ~0.1 T at the center. Experiments and simulations have been performed for single and double anode ring configurations using helium gas discharge, which infer that double ring configuration gives better light emissions in the large volume Penning plasma discharge arrangement. The optical emission spectroscopy measurements are used to complement the observations. The spectral line-ratio technique is utilized to determine the electron plasma density. The estimated electron plasma density in double ring plasma configuration is ~2 × 10(11) cm(-3), which is around one order of magnitude larger than that of single ring arrangement.

  8. Clinical, biochemical, and hormonal changes after a single, large-volume paracentesis in cirrhosis with ascites.

    PubMed

    Gentile, S; Angelico, M; Bologna, E; Capocaccia, L

    1989-03-01

    The use of paracentesis has recently been reproposed as a safe and effective alternative to diuretics for management of ascites. We have investigated the clinical and biochemical effects of large-volume paracentesis in 19 cirrhotics with tense ascites, and the relative changes in the hormones involved in sodium and water renal handling. Plasma renin activity (PRA), aldosterone (PA), and arginine vasopressin (AVP) levels and conventional liver and renal function tests were measured before and after 1, 2, and 7 days after the paracentesis. No complications were observed, but patients regained 37% of the weight lost after 1 wk. Percent weight regained was significantly and directly correlated with PA concentration measured before the paracentesis. No changes were recorded after paracentesis in biochemical and clinical data, except for a significant drop in diastolic blood pressure. No changes in AVP levels were observed. A significant increase in PA occurred after paracentesis, with a maximum peak after 48 h. The increase in PA was not accompanied by changes in PRA, but was associated with a reduction of urinary sodium excretion. A relevant fraction of body aldosterone was confined to the ascitic fluid. We conclude that the clinical results of a large-volume paracentesis can be predicted in part on the basis of PA measurement, and that removal of ascites is followed by an increase of PA of uncertain origin and effectiveness.

  9. Specific detection of DNA using quantum dots and magnetic beads for large volume samples

    SciTech Connect

    Kim, Yeon S.; Kim, Byoung CHAN; Lee, Jin Hyung; Kim, Jungbae; Gu, Man Bock

    2006-10-01

    Here we present a sensitive DNA detection protocol using quantum dots (QDs) and magnetic beads (MBs) for large volume samples. In this study, QDs, conjugated with streptavidin, were used to produce fluorescent signals while magnetic beads (MBs) were used to isolate and concentrate the signals. The presence of target DNAs lead to the sandwich hybridization between the functionalized QDs, the target DNAs and the MBs. In fact, the QDs-MBs complex, which is bound using the target DNA, can be isolated and then concentrated. The binding of the QDs to the surface of the MBs was confirmed by confocal microscopy and Cd elemental analysis. It was found that the fluorescent intensity was proportional to concentration of the target DNA, while the presence of noncomplementary DNA produced no significant fluorescent signal. In addition, the presence of low copies of target DNAs such as 0.5 pM in large volume samples up to 40 ml were successfully detected by using a magnet-assisted concentration protocol which consequently results in the enhancement of the sensitivity more than 100-fold.

  10. Development of large volume double ring penning plasma discharge source for efficient light emissions

    SciTech Connect

    Prakash, Ram; Vyas, Gheesa Lal; Jain, Jalaj; Prajapati, Jitendra; Pal, Udit Narayan; Chowdhuri, Malay Bikas; Manchanda, Ranjana

    2012-12-15

    In this paper, the development of large volume double ring Penning plasma discharge source for efficient light emissions is reported. The developed Penning discharge source consists of two cylindrical end cathodes of stainless steel having radius 6 cm and a gap 5.5 cm between them, which are fitted in the top and bottom flanges of the vacuum chamber. Two stainless steel anode rings with thickness 0.4 cm and inner diameters 6.45 cm having separation 2 cm are kept at the discharge centre. Neodymium (Nd{sub 2}Fe{sub 14}B) permanent magnets are physically inserted behind the cathodes for producing nearly uniform magnetic field of {approx}0.1 T at the center. Experiments and simulations have been performed for single and double anode ring configurations using helium gas discharge, which infer that double ring configuration gives better light emissions in the large volume Penning plasma discharge arrangement. The optical emission spectroscopy measurements are used to complement the observations. The spectral line-ratio technique is utilized to determine the electron plasma density. The estimated electron plasma density in double ring plasma configuration is {approx}2 Multiplication-Sign 10{sup 11} cm{sup -3}, which is around one order of magnitude larger than that of single ring arrangement.

  11. Colloids Versus Albumin in Large Volume Paracentesis to Prevent Circulatory Dysfunction: Evidence-based Case Report.

    PubMed

    Widjaja, Felix F; Khairan, Paramita; Kamelia, Telly; Hasan, Irsan

    2016-04-01

    Large volume paracentesis may cause paracentesis induced circulatory dysfunction (PICD). Albumin is recommended to prevent this abnormality. Meanwhile, the price of albumin is too expensive and there should be another alternative that may prevent PICD. This report aimed to compare albumin to colloids in preventing PICD. Search strategy was done using PubMed, Scopus, Proquest, dan Academic Health Complete from EBSCO with keywords of "ascites", "albumin", "colloid", "dextran", "hydroxyethyl starch", "gelatin", and "paracentesis induced circulatory dysfunction". Articles was limited to randomized clinical trial and meta-analysis with clinical question of "In hepatic cirrhotic patient undergone large volume paracentesis, whether colloids were similar to albumin to prevent PICD". We found one meta-analysis and four randomized clinical trials (RCT). A meta analysis showed that albumin was still superior of which odds ratio 0.34 (0.23-0.51). Three RCTs showed the same results and one RCT showed albumin was not superior than colloids. We conclude that colloids could not constitute albumin to prevent PICD, but colloids still have a role in patient who undergone paracentesis less than five liters.

  12. Broadband frequency ECR ion source concepts with large resonant plasma volumes

    SciTech Connect

    Alton, G.D.

    1995-12-31

    New techniques are proposed for enhancing the performances of ECR ion sources. The techniques are based on the use of high-power, variable-frequency, multiple-discrete-frequency, or broadband microwave radiation, derived from standard TWT technology, to effect large resonant ``volume`` ECR sources. The creation of a large ECR plasma ``volume`` permits coupling of more power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present forms of the ECR ion source. If successful, these developments could significantly impact future accelerator designs and accelerator-based, heavy-ion-research programs by providing multiply-charged ion beams with the energies and intensities required for nuclear physics research from existing ECR ion sources. The methods described in this article can be used to retrofit any ECR ion source predicated on B-minimum plasma confinement techniques.

  13. Large-volume flux closure during plasmoid-mediated reconnection in coaxial helicity injection

    SciTech Connect

    Ebrahimi, F.; Raman, R.

    2016-03-23

    A large-volume flux closure during transient coaxial helicity injection (CHI) in NSTX-U is demonstrated through resistive magnetohydrodynamics (MHD) simulations. Several major improvements, including the improved positioning of the divertor poloidal field coils, are projected to improve the CHI start-up phase in NSTX-U. Simulations in the NSTX-U configuration with constant in time coil currents show that with strong flux shaping the injected open field lines (injector flux) rapidly reconnect and form large volume of closed flux surfaces. This is achieved by driving parallel current in the injector flux coil and oppositely directed currents in the flux shaping coils to form a narrow injector flux footprint and push the injector flux into the vessel. As the helicity and plasma are injected into the device, the oppositely directed field lines in the injector region are forced to reconnect through a local Sweet-Parker type reconnection, or to spontaneously reconnect when the elongated current sheet becomes MHD unstable to form plasmoids. In these simulations for the first time, it is found that the closed flux is over 70% of the initial injector flux used to initiate the discharge. Furthermore, these results could work well for the application of transient CHI in devices that employ super conducting coils to generate and sustain the plasma equilibrium.

  14. Large-volume flux closure during plasmoid-mediated reconnection in coaxial helicity injection

    DOE PAGES

    Ebrahimi, F.; Raman, R.

    2016-03-23

    A large-volume flux closure during transient coaxial helicity injection (CHI) in NSTX-U is demonstrated through resistive magnetohydrodynamics (MHD) simulations. Several major improvements, including the improved positioning of the divertor poloidal field coils, are projected to improve the CHI start-up phase in NSTX-U. Simulations in the NSTX-U configuration with constant in time coil currents show that with strong flux shaping the injected open field lines (injector flux) rapidly reconnect and form large volume of closed flux surfaces. This is achieved by driving parallel current in the injector flux coil and oppositely directed currents in the flux shaping coils to form amore » narrow injector flux footprint and push the injector flux into the vessel. As the helicity and plasma are injected into the device, the oppositely directed field lines in the injector region are forced to reconnect through a local Sweet-Parker type reconnection, or to spontaneously reconnect when the elongated current sheet becomes MHD unstable to form plasmoids. In these simulations for the first time, it is found that the closed flux is over 70% of the initial injector flux used to initiate the discharge. Furthermore, these results could work well for the application of transient CHI in devices that employ super conducting coils to generate and sustain the plasma equilibrium.« less

  15. Pathways of deep cyclones associated with large volume changes (LVCs) and major Baltic inflows (MBIs)

    NASA Astrophysics Data System (ADS)

    Lehmann, Andreas; Höflich, Katharina; Post, Piia; Myrberg, Kai

    2017-03-01

    Large volume changes (LVCs) and major Baltic inflows (MBIs) are essential processes for the water exchange and renewal of the stagnant water in the Baltic Sea deep basins. These strong inflows are known to be forced by persistent westerly wind conditions. In this study, MBIs are considered as subset of LVCs transporting with the large water volume a big amount of highly saline and oxygenated water into the Baltic Sea. Since the early 1980s the frequency of MBIs has dropped drastically from 5 to 7 events to only one inflow per decade, and long lasting periods without MBIs became the usual state. Only in January 1993, 2003 and December 2014 MBIs occurred that were able to interrupt the stagnation periods in the deep basins of the Baltic Sea. However, in spite of the decreasing frequency of MBIs, there is no obvious decrease of LVCs. The Landsort sea level is known to reflect the mean sea level of the Baltic Sea very well, and hence LVCs have been calculated for the period 1887-2015 filtering daily time series of Landsort sea surface elevation anomalies. The cases with local minimum and maximum difference resulting in at least 60 km3 of water volume change excluding the volume change due to runoff have been chosen for a closer study (1948-2013) of characteristic pathways of deep cyclones. The average duration of LVCs is about 40 days. During this time, 5-6 deep cyclones move along characteristic storm tracks. Furthermore, MBIs are characterized by even higher cyclonic activity compared to average LVCs. We obtained four main routes of deep cyclones which were associated with LVCs, but also with the climatology. One is approaching from the west at about 56-60°N, passing the northern North Sea, northern Denmark, Sweden and the Island of Gotland. A second broad corridor of frequent cyclone pathways enters the study area north of Scotland between 60 and 66°N turning north-eastwards along the northern coast of Scandinavia. This branch bifurcates into smaller routes. One

  16. Calcium isolation from large-volume human urine samples for 41Ca analysis by accelerator mass spectrometry.

    PubMed

    Miller, James J; Hui, Susanta K; Jackson, George S; Clark, Sara P; Einstein, Jane; Weaver, Connie M; Bhattacharyya, Maryka H

    2013-08-01

    Calcium oxalate precipitation is the first step in preparation of biological samples for (41)Ca analysis by accelerator mass spectrometry. A simplified protocol for large-volume human urine samples was characterized, with statistically significant increases in ion current and decreases in interference. This large-volume assay minimizes cost and effort and maximizes time after (41)Ca administration during which human samples, collected over a lifetime, provide (41)Ca:Ca ratios that are significantly above background.

  17. Predicting nurse staffing needs for a labor and birth unit in a large-volume perinatal service.

    PubMed

    Simpson, Kathleen Rice

    2015-01-01

    This project was designed to test a nurse staffing model for its ability to accurately determine staffing needs for a large-volume labor and birth unit based on a staffing gap analysis using the nurse staffing guidelines from the Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN). The staffing model and the AWHONN staffing guidelines were found to be reliable methods to predict staffing needs for a large-volume labor and birth unit.

  18. Safety of large-volume leukapheresis for collection of peripheral blood progenitor cells.

    PubMed

    Reik, R A; Noto, T A; Fernandez, H F

    1997-01-01

    Large volume leukapheresis (LVL) reduces the number of procedures required to obtain adequate peripheral blood progenitor cells (PBPCs) for autologous hematopoietic reconstitution. LVL involves the processing of > 15 L or 5 patient blood volumes using high flow rates. We report our experience with LVL evaluating its efficiency and adverse effects in 71 adult patients with hematologic or solid organ malignancies. All were mobilized with chemotherapy and granulocyte colony-stimulating factor (G-CSF). All collections used a double lumen apheresis catheter. Mean values per LVL were as follows: blood processed, 24.6 L; patient blood volumes processed, 5.9; ACD-A used, 1,048 ml; heparin used, 6,148 units; collect time, 290 min; blood flow rate, 89 ml/min. Eighty percent of the collections were completed in one or two procedures to obtain > or = 6.0 x 10(8) MNCs/kg body weight. The most frequent side effect (39%) was parasthesia due to citrate-related hypocalcemia. This was managed with oral calcium supplements and/or slower flow rates. Post-LVL electrolyte changes were generally asymptomatic. Prophylactic oral potassium supplements were administered in 57% of cases. Other reactions included hypotension (4%), prolonged parasthesia (1.4%), and headache (1.4%). Catheter problems in 9 (13%) of the procedures were attributed to clot formation (37%) or positional effects (63%). No bleeding occurred. Post-LVL decreases in hematocrit and platelet count averaged 3.5% and 46%, respectively. Six (4%) of the procedures required red blood cell transfusions. Platelet transfusions were given in 19 (13%) of the procedures. We conclude that adverse reactions with LVL are similar to those reported for conventional PBPC collections, making it safe and efficacious as an outpatient procedure.

  19. Collection of more hematopoietic progenitor cells with large volume leukapheresis in patients with multiple myeloma.

    PubMed

    Desikan, K R; Jagannath, S; Siegel, D; Nelson, J; Bracy, D; Barlogie, B; Tricot, G

    1998-02-01

    Reinfusion of mobilized peripheral blood stem cells (PBSC) after high dose chemotherapy accelerates hematopoietic recovery. Because of the relatively low content of hematopoietic progenitors in the peripheral blood even after mobilization, multiple leukapheresis procedures are necessary to reach the required target number of CD34 cells to ensure prompt engraftment post-transplantation. Our previous studies have shown that the highest proportions of hematopoietic progenitors cells (CD34) are collected during the first three days of apheresis, whereas peak levels of myeloma cells are observed during subsequent days. Therefore, large volume leukapheresis (LVL), defined as processing of greater than 3 blood volumes or a total of at least 15 liters, was explored in 23 myeloma patients, undergoing 91 procedures; 14 patients were mobilized with high dose cyclophosphamide (6g/m2) and hematopoietic growth factors and 9 with G-CSF only. CD34 yields were measured separately for the first and last two hours of collection. We observed no decrease in CD34 cells/kg during the last two hours of collection and when the LVL collections were compared to historical matched controls, mobilized with the same regimen, the median quantity of CD34 cells/kg/liter collected remained equivalent during all days of apheresis. When compared to G-CSF only, mobilization with high dose cyclophosphamide appeared to result in superior hematopoietic stem cell collections. Interestingly, the G-CSF group experienced a progressive decrease in platelets during consecutive days of LVL, while the opposite was seen in the cyclophosphamide group. LVL procedures were not associated with a higher complication rate than standard volume apheresis. We conclude that LVL procedures allow collection of more CD34 cell per session while not jeopardizing progenitor cell collections during subsequent sessions. Since more CD34 cells are collected, fewer days are required to attain the optimal target of progenitor cells

  20. Random forest classification of large volume structures for visuo-haptic rendering in CT images

    NASA Astrophysics Data System (ADS)

    Mastmeyer, Andre; Fortmeier, Dirk; Handels, Heinz

    2016-03-01

    For patient-specific voxel-based visuo-haptic rendering of CT scans of the liver area, the fully automatic segmentation of large volume structures such as skin, soft tissue, lungs and intestine (risk structures) is important. Using a machine learning based approach, several existing segmentations from 10 segmented gold-standard patients are learned by random decision forests individually and collectively. The core of this paper is feature selection and the application of the learned classifiers to a new patient data set. In a leave-some-out cross-validation, the obtained full volume segmentations are compared to the gold-standard segmentations of the untrained patients. The proposed classifiers use a multi-dimensional feature space to estimate the hidden truth, instead of relying on clinical standard threshold and connectivity based methods. The result of our efficient whole-body section classification are multi-label maps with the considered tissues. For visuo-haptic simulation, other small volume structures would have to be segmented additionally. We also take a look into these structures (liver vessels). For an experimental leave-some-out study consisting of 10 patients, the proposed method performs much more efficiently compared to state of the art methods. In two variants of leave-some-out experiments we obtain best mean DICE ratios of 0.79, 0.97, 0.63 and 0.83 for skin, soft tissue, hard bone and risk structures. Liver structures are segmented with DICE 0.93 for the liver, 0.43 for blood vessels and 0.39 for bile vessels.

  1. Measurements of Elastic and Inelastic Properties under Simulated Earth's Mantle Conditions in Large Volume Apparatus

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.

    2012-12-01

    The interpretation of highly resolved seismic data from Earths deep interior require measurements of the physical properties of Earth's materials under experimental simulated mantle conditions. More than decade ago seismic tomography clearly showed subduction of crustal material can reach the core mantle boundary under specific circumstances. That means there is no longer space for the assumption deep mantle rocks might be much less complex than deep crustal rocks known from exhumation processes. Considering this geophysical high pressure research is faced the challenge to increase pressure and sample volume at the same time to be able to perform in situ experiments with representative complex samples. High performance multi anvil devices using novel materials are the most promising technique for this exciting task. Recent large volume presses provide sample volumes 3 to 7 orders of magnitude bigger than in diamond anvil cells far beyond transition zone conditions. The sample size of several cubic millimeters allows elastic wave frequencies in the low to medium MHz range. Together with the small and even adjustable temperature gradients over the whole sample this technique makes anisotropy and grain boundary effects in complex systems accessible for elastic and inelastic properties measurements in principle. The measurements of both elastic wave velocities have also no limits for opaque and encapsulated samples. The application of triple-mode transducers and the data transfer function technique for the ultrasonic interferometry reduces the time for saving the data during the experiment to about a minute or less. That makes real transient measurements under non-equilibrium conditions possible. A further benefit is, both elastic wave velocities are measured exactly simultaneously. Ultrasonic interferometry necessarily requires in situ sample deformation measurement by X-radiography. Time-resolved X-radiography makes in situ falling sphere viscosimetry and even the

  2. Determination of the large scale volume weighted halo velocity bias in simulations

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Zhang, Pengjie; Jing, Yipeng

    2015-06-01

    A profound assumption in peculiar velocity cosmology is bv=1 at sufficiently large scales, where bv is the volume-weighted halo(galaxy) velocity bias with respect to the matter velocity field. However, this fundamental assumption has not been robustly verified in numerical simulations. Furthermore, it is challenged by structure formation theory (Bardeen, Bond, Kaiser and Szalay, Astrophys. J. 304, 15 (1986); Desjacques and Sheth, Phys. Rev D 81, 023526 (2010), which predicts the existence of velocity bias (at least for proto-halos) due to the fact that halos reside in special regions (local density peaks). The major obstacle to measuring the volume-weighted velocity from N-body simulations is an unphysical sampling artifact. It is entangled in the measured velocity statistics and becomes significant for sparse populations. With recently improved understanding of the sampling artifact (Zhang, Zheng and Jing, 2015, PRD; Zheng, Zhang and Jing, 2015, PRD), for the first time we are able to appropriately correct this sampling artifact and then robustly measure the volume-weighted halo velocity bias. (1) We verify bv=1 within 2% model uncertainty at k ≲0.1 h /Mpc and z =0 - 2 for halos of mass ˜1012- 1013h-1M⊙ and, therefore, consolidate a foundation for the peculiar velocity cosmology. (2) We also find statistically significant signs of bv≠1 at k ≳0.1 h /Mpc . Unfortunately, whether this is real or caused by a residual sampling artifact requires further investigation. Nevertheless, cosmology based on the k ≳0.1 h /Mpc velocity data should be careful with this potential velocity bias.

  3. THE EFFECT OF VARIOUS DETECTOR GEOMETRIES ON THE PERFORMANCE OF CZT USING ONE CRYSTAL

    SciTech Connect

    Washington, A.; Duff, M.; Teague, L.

    2011-06-21

    CdZnTe (CZT) continues to be a major thrust interest mainly due to its potential application as a room temperature radiation detector. The performance of CZT detectors is directly related to the charge collection ability which can be affected by the configuration of the electrical contact. The charge collection efficiency is determined in part by the specific geometry of the anode contact which serves as the readout electrode. In this report, contact geometries including single pixel, planar, coplanar, and dual anode will be systematically explored by comparing the performance efficiencies of the detector using both low and high energy gamma rays. To help eliminate the effect of crystal quality variations, the contact geometries were fabricated on the same crystal detector with minimal polishing between contact placements.

  4. Te Inclusions in CZT Detectors: New Method for Correcting Their Adverse Effects

    SciTech Connect

    Bolotnikov, A.E.; Babalola, S.; Camarda, G.S.; Cui, Y.; Egarievwe, S.U.; Hawrami, R.; Hossain, A.; Yang, G.; James, R.B.

    2009-10-25

    Both Te inclusions and point defects can trap the charge carriers generated by ionizing particles in CdZnTe (CZT) detectors. The amount of charge trapped by point defects is proportional to the carriers’ drift time and can be corrected electronically. In the case of Te inclusions, the charge loss depends upon their random locations with respect to the electron cloud. Consequently, inclusions introduce fluctuations in the charge signals, which cannot be easily corrected. In this paper, we describe direct measurements of the cumulative effect of Te inclusions and its influence on the response of CZT detectors of different thicknesses and different sizes and concentrations of Te inclusions. We also discuss a means of partially correcting their adverse effects.

  5. Characterization of Single-Sided Charge-Sharing CZT Strip Detectors for Gamma-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Donmez, Burcin; Macri, John R.; Ryan, James M.; Legere, Jason S.; McConnell, Mark L.; Widholm, Mark; Narita, Tomohiko; Hamel, Louis-Andre

    2006-01-01

    We report progress in the study of thick single-sided charge-sharing cadmium zinc telluride (CZT) strip detector modules designed to perform spectroscopy and 3-D imaging of gamma-rays. We report laboratory measurements including spectroscopy, efficiency and 3-D imaging capability of prototype detectors (15 15 7.5 cu mm) with 11x11 unit cells. We also report on Monte Carlo simulations (GEANT4 v7.1) to investigate the effect of multihits on detector performance in both spectroscopy and imaging. We compare simulation results with data obtained from laboratory measurements and discuss the implications for future strip detector designs. Keywords: CZT, strip detectors, gamma-ray

  6. Large-Volume Resonant Microwave Discharge for Plasma Cleaning of a CEBAF 5-Cell SRF Cavity

    SciTech Connect

    J. Mammosser, S. Ahmed, K. Macha, J. Upadhyay, M. Nikoli, S. Popovi, L. Vuakovi

    2012-07-01

    We report the preliminary results on plasma generation in a 5-cell CEBAF superconducting radio-frequency (SRF) cavity for the application of cavity interior surface cleaning. CEBAF currently has {approx}300 of these five cell cavities installed in the Jefferson Lab accelerator which are mostly limited by cavity surface contamination. The development of an in-situ cavity surface cleaning method utilizing a resonant microwave discharge could lead to significant CEBAF accelerator performance improvement. This microwave discharge is currently being used for the development of a set of plasma cleaning procedures targeted to the removal of various organic, metal and metal oxide impurities. These contaminants are responsible for the increase of surface resistance and the reduction of RF performance in installed cavities. The CEBAF five cell cavity volume is {approx} 0.5 m2, which places the discharge in the category of large-volume plasmas. CEBAF cavity has a cylindrical symmetry, but its elliptical shape and transversal power coupling makes it an unusual plasma application, which requires special consideration of microwave breakdown. Our preliminary study includes microwave breakdown and optical spectroscopy, which was used to define the operating pressure range and the rate of removal of organic impurities.

  7. A large volume cell for in situ neutron diffraction studies of hydrothermal crystallizations.

    PubMed

    Xia, Fang; Qian, Gujie; Brugger, Joël; Studer, Andrew; Olsen, Scott; Pring, Allan

    2010-10-01

    A hydrothermal cell with 320 ml internal volume has been designed and constructed for in situ neutron diffraction studies of hydrothermal crystallizations. The cell design adopts a dumbbell configuration assembled with standard commercial stainless steel components and a zero-scattering Ti-Zr alloy sample compartment. The fluid movement and heat transfer are simply driven by natural convection due to the natural temperature gradient along the fluid path, so that the temperature at the sample compartment can be stably sustained by heating the fluid in the bottom fluid reservoir. The cell can operate at temperatures up to 300 °C and pressures up to 90 bars and is suitable for studying reactions requiring a large volume of hydrothermal fluid to damp out the negative effect from the change of fluid composition during the course of the reactions. The capability of the cell was demonstrated by a hydrothermal phase transformation investigation from leucite (KAlSi(2)O(6)) to analcime (NaAlSi(2)O(6)⋅H(2)O) at 210 °C on the high intensity powder diffractometer Wombat in ANSTO. The kinetics of the transformation has been resolved by collecting diffraction patterns every 10 min followed by Rietveld quantitative phase analysis. The classical Avrami/Arrhenius analysis gives an activation energy of 82.3±1.1 kJ  mol(-1). Estimations of the reaction rate under natural environments by extrapolations agree well with petrological observations.

  8. A large volume cell for in situ neutron diffraction studies of hydrothermal crystallizations

    NASA Astrophysics Data System (ADS)

    Xia, Fang; Qian, Gujie; Brugger, Joël; Studer, Andrew; Olsen, Scott; Pring, Allan

    2010-10-01

    A hydrothermal cell with 320 ml internal volume has been designed and constructed for in situ neutron diffraction studies of hydrothermal crystallizations. The cell design adopts a dumbbell configuration assembled with standard commercial stainless steel components and a zero-scattering Ti-Zr alloy sample compartment. The fluid movement and heat transfer are simply driven by natural convection due to the natural temperature gradient along the fluid path, so that the temperature at the sample compartment can be stably sustained by heating the fluid in the bottom fluid reservoir. The cell can operate at temperatures up to 300 °C and pressures up to 90 bars and is suitable for studying reactions requiring a large volume of hydrothermal fluid to damp out the negative effect from the change of fluid composition during the course of the reactions. The capability of the cell was demonstrated by a hydrothermal phase transformation investigation from leucite (KAlSi2O6) to analcime (NaAlSi2O6ṡH2O) at 210 °C on the high intensity powder diffractometer Wombat in ANSTO. The kinetics of the transformation has been resolved by collecting diffraction patterns every 10 min followed by Rietveld quantitative phase analysis. The classical Avrami/Arrhenius analysis gives an activation energy of 82.3±1.1 kJ mol-1. Estimations of the reaction rate under natural environments by extrapolations agree well with petrological observations.

  9. A Scanning Transmission Electron Microscopy (STEM) Approach to Analyzing Large Volumes of Tissue to Detect Nanoparticles

    PubMed Central

    Kempen, Paul J.; Thakor, Avnesh S.; Zavaleta, Cristina; Gambhir, Sanjiv S.; Sinclair, Robert

    2013-01-01

    The use of nanoparticles for the diagnosis and treatment of cancer requires the complete characterization of their toxicity, including accurately locating them within biological tissues. Owing to their size, traditional light microscopy techniques are unable to resolve them. Transmission electron microscopy provides the necessary spatial resolution to image individual nanoparticles in tissue but is severely limited by the very small analysis volume, usually on the order of tens of cubic microns. In this work we developed a scanning transmission electron microscopy (STEM) approach to analyze large volumes of tissue for the presence of polyethylene glycol coated Raman-active-silica-gold-nanoparticles (PEG-R-Si-Au-NPs). This approach utilizes the simultaneous bright and dark field imaging capabilities of STEM along with careful control of the image contrast settings to readily identify PEG-R-Si-Au-NPs in mouse liver tissue without the need for additional time consuming analytical characterization. We utilized this technique to analyze 243,000 µm3 of mouse liver tissue for the presence of PEG-R-Si-Au-NPs. Nanoparticles injected into the mice intravenously via the tail-vein accumulated in the liver while those injected intrarectally did not, indicating that they remain in the colon and do not pass through the colon wall into the systemic circulation. PMID:23803218

  10. Evaluation of Large Volume SrI2(Eu) Scintillator Detectors

    SciTech Connect

    Sturm, B W; Cherepy, N J; Drury, O B; Thelin, P A; Fisher, S E; Magyar, A F; Payne, S A; Burger, A; Boatner, L A; Ramey, J O; Shah, K S; Hawrami, R

    2010-11-18

    There is an ever increasing demand for gamma-ray detectors which can achieve good energy resolution, high detection efficiency, and room-temperature operation. We are working to address each of these requirements through the development of large volume SrI{sub 2}(Eu) scintillator detectors. In this work, we have evaluated a variety of SrI{sub 2} crystals with volumes >10 cm{sup 3}. The goal of this research was to examine the causes of energy resolution degradation for larger detectors and to determine what can be done to mitigate these effects. Testing both packaged and unpackaged detectors, we have consistently achieved better resolution with the packaged detectors. Using a collimated gamma-ray source, it was determined that better energy resolution for the packaged detectors is correlated with better light collection uniformity. A number of packaged detectors were fabricated and tested and the best spectroscopic performance was achieved for a 3% Eu doped crystal with an energy resolution of 2.93% FWHM at 662keV. Simulations of SrI{sub 2}(Eu) crystals were also performed to better understand the light transport physics in scintillators and are reported. This study has important implications for the development of SrI{sub 2}(Eu) detectors for national security purposes.

  11. A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma

    SciTech Connect

    Yang Min; Li Xiaoping; Xie Kai; Liu Donglin; Liu Yanming

    2013-01-15

    A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a 'black out' phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm Multiplication-Sign 260 mm Multiplication-Sign 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.

  12. A scanning transmission electron microscopy approach to analyzing large volumes of tissue to detect nanoparticles.

    PubMed

    Kempen, Paul J; Thakor, Avnesh S; Zavaleta, Cristina; Gambhir, Sanjiv S; Sinclair, Robert

    2013-10-01

    The use of nanoparticles for the diagnosis and treatment of cancer requires the complete characterization of their toxicity, including accurately locating them within biological tissues. Owing to their size, traditional light microscopy techniques are unable to resolve them. Transmission electron microscopy provides the necessary spatial resolution to image individual nanoparticles in tissue, but is severely limited by the very small analysis volume, usually on the order of tens of cubic microns. In this work, we developed a scanning transmission electron microscopy (STEM) approach to analyze large volumes of tissue for the presence of polyethylene glycol-coated Raman-active-silica-gold-nanoparticles (PEG-R-Si-Au-NPs). This approach utilizes the simultaneous bright and dark field imaging capabilities of STEM along with careful control of the image contrast settings to readily identify PEG-R-Si-Au-NPs in mouse liver tissue without the need for additional time-consuming analytical characterization. We utilized this technique to analyze 243,000 mm³ of mouse liver tissue for the presence of PEG-R-Si-Au-NPs. Nanoparticles injected into the mice intravenously via the tail vein accumulated in the liver, whereas those injected intrarectally did not, indicating that they remain in the colon and do not pass through the colon wall into the systemic circulation.

  13. Computation and volume rendering of large-scale EOF coherent modes in rotating turbulent flow data

    NASA Astrophysics Data System (ADS)

    Ostrouchov, G.; Pugmire, D.; Rosenberg, D. L.; Chen, W.; Pouquet, A.

    2013-12-01

    The computation of empirical orthogonal functions (EOF) is used to extract major coherent modes of variability in spatio-temporal data. We explore the computation of EOF in three spatial dimensions over time and present the result with volume rendering software. To accomplish this, we use an HPC extension of the R language, pbdR (see r-pbd.org), that we embed in the VisIt visualization system. VisIt provides parallel data reader capability as well as the volume rendering ability to present the computed EOFs. The data we consider derives from direct numerical simulation on a grid of 20483 points of rapidly rotating turbulent flows that are forced at intermediate scales. Injection of energy at these scales at small Rossby number (~0.04) leads to a direct cascade of energy to small scales, and an inverse cascade to large scales. We will use pdbR to examine the spatio-temporal interactions and ergodicity of waves and turbulent eddies in these flows.

  14. Detection of fast flying nanoparticles by light scattering over a large volume

    NASA Astrophysics Data System (ADS)

    Pettazzi, F.; Bäumer, S.; van der Donck, J.; Deutz, A.

    2015-06-01

    is a well-known detection method which is applied in many different scientific and technology domains including atmospheric physics, environmental control, and biology. It allows contactless and remote detection of sub-micron size particles. However, methods for detecting a single fast moving particle smaller than 100 nm are lacking. In the present work we report a preliminary design study of an inline large area detector for nanoparticles larger than 50 nm which move with velocities up to 100 m/s. The detector design is based on light scattering using commercially available components. The presented design takes into account all challenges connected to the inline implementation of the scattering technique in the system: the need for the detector to have a large field of view to cover a volume with a footprint commensurate to an area of 100mm x 100mm, the necessity to sense nanoparticles transported at high velocity, and the requirement of large capture rate with a false detection as low as one false positive per week. The impact of all these stringent requirements on the expected sensitivity and performances of the device is analyzed by mean of a dedicated performance model.

  15. Isolation of organic acids from large volumes of water by adsorption chromatography

    USGS Publications Warehouse

    Aiken, George R.

    1984-01-01

    The concentrations of dissolved organic carbon from most natural waters ranges from 1 to 20 milligrams carbon per liter, of which approximately 75 percent are organic acids. These acids can be chromatographically fractionated into hydrophobic organic acids, such as humic substances, and hydrophilic organic acids. To effectively study any of these organic acids, they must be isolated from other organic and inorganic species, and concentrated. Usually, large volumes of water must be processed to obtain sufficient quantities of material, and adsorption chromatography on synthetic, macroporous resins has proven to be a particularly effective method for this purpose. The use of the nonionic Amberlite XAD-8 and Amberlite XAD-4 resins and the anion exchange resin Duolite A-7 for isolating and concentrating organic acids from water is presented.

  16. A large volume 2000 MPA air source for the radiatively driven hypersonic wind tunnel

    SciTech Connect

    Constantino, M

    1999-07-14

    An ultra-high pressure air source for a hypersonic wind tunnel for fluid dynamics and combustion physics and chemistry research and development must provide a 10 kg/s pure air flow for more than 1 s at a specific enthalpy of more than 3000 kJ/kg. The nominal operating pressure and temperature condition for the air source is 2000 MPa and 900 K. A radial array of variable radial support intensifiers connected to an axial manifold provides an arbitrarily large total high pressure volume. This configuration also provides solutions to cross bore stress concentrations and the decrease in material strength with temperature. [hypersonic, high pressure, air, wind tunnel, ground testing

  17. Monte Carlo calculations of the HPGe detector efficiency for radioactivity measurement of large volume environmental samples.

    PubMed

    Azbouche, Ahmed; Belgaid, Mohamed; Mazrou, Hakim

    2015-08-01

    A fully detailed Monte Carlo geometrical model of a High Purity Germanium detector with a (152)Eu source, packed in Marinelli beaker, was developed for routine analysis of large volume environmental samples. Then, the model parameters, in particular, the dead layer thickness were adjusted thanks to a specific irradiation configuration together with a fine-tuning procedure. Thereafter, the calculated efficiencies were compared to the measured ones for standard samples containing (152)Eu source filled in both grass and resin matrices packed in Marinelli beaker. From this comparison, a good agreement between experiment and Monte Carlo calculation results was obtained highlighting thereby the consistency of the geometrical computational model proposed in this work. Finally, the computational model was applied successfully to determine the (137)Cs distribution in soil matrix. From this application, instructive results were achieved highlighting, in particular, the erosion and accumulation zone of the studied site.

  18. Improved large-volume sampler for the collection of bacterial cells from aerosol.

    PubMed

    White, L A; Hadley, D J; Davids, D E; Naylor, R

    1975-03-01

    A modified large-volume sampler was demonstrated to be an efficient device for the collection of mono-disperse aerosols of rhodamine B and poly-disperse aerosols of bacterial cells. Absolute efficiency for collection of rhodamine B varied from 100% with 5-mum particles to about 70% with 0.5-mum particles. The sampler concentrated the particles from 950 liters of air into a flow of between 1 and 2 ml of collecting fluid per min. Spores of Bacillus subtilis var. niger were collected at an efficiency of about 82% compared to the collection in the standard AGI-30 sampler. In the most desirable collecting fluids tested, aerosolized cells of Serratia marcescens, Escherichia coli, and Aerobacter aerogenes were collected at comparative efficiencies of approximately 90, 80, and 90%, respectively. The modified sampler has practical application in the study of aerosol transmission of respiratory pathogens.

  19. AC Magnetic Properties of Large Volume of Water — Susceptibility Measurement in Unshielded Environment

    NASA Astrophysics Data System (ADS)

    Tsukada, Keiji; Kiwa, Toshihiko; Masuda, Yuuki

    2006-10-01

    To investigate the effect of low-frequency magnetic-field exposure of a human body, the low-frequency AC magnetic property of a large volume of water was measured by low-frequency magnetic field exposure (from 50 Hz to 1.2 kHz). The results indicate that the AC magnetic property of water is due to diamagnetism in the low-frequency range. The phase between the main magnetic field and the generated magnetic field remained constant at about 180°. Results were not affected by conductivity or pH. Moreover, the magnetic-field strength from water showed a susceptibility frequency dependence proportional to the frequency above approximately 400 Hz. Because of the incremental effects of susceptibility, the magnetic field from water was measured using a conventional magnetic sensor (magnetic resistive; MR) in an unshielded environment.

  20. Isolation of organic acids from large volumes of water by adsorption on macroporous resins

    USGS Publications Warehouse

    Aiken, George R.; Suffet, I.H.; Malaiyandi, Murugan

    1987-01-01

    Adsorption on synthetic macroporous resins, such as the Amberlite XAD series and Duolite A-7, is routinely used to isolate and concentrate organic acids from forge volumes of water. Samples as large as 24,500 L have been processed on site by using these resins. Two established extraction schemes using XAD-8 and Duolite A-7 resins are described. The choice of the appropriate resin and extraction scheme is dependent on the organic solutes of interest. The factors that affect resin performance, selectivity, and capacity for a particular solute are solution pH, resin surface area and pore size, and resin composition. The logistical problems of sample handling, filtration, and preservation are also discussed.

  1. Large volume liquid helium relief device verifacation apparatus for the alpha magnetic spectrometer

    NASA Astrophysics Data System (ADS)

    Klimas, Richard John; McIntyre, P.; Colvin, John; Zeigler, John; Van Sciver, Steven; Ting, Samual

    2012-06-01

    Here we present details of an experiment for verifying the liquid helium vessel relief device for the Alpha Magnetic Spectrometer-02 (AMS-02). The relief device utilizes a series of rupture discs designed to open in the event of a vacuum failure of the AMS-02 cryogenic system. A failure of this type is classified to be a catastrophic loss of insulating vacuum accident. This apparatus differs from other approaches due to the size of the test volumes used. The verification apparatus consists of a 250 liter vessel used for the test quantity of liquid helium that is located inside a vacuum insulated vessel. A large diameter valve is suddenly opened to simulate the loss of insulating vacuum in a repeatable manner. Pressure and temperature vs. time data are presented and discussed in the context of the AMS-02 hardware configuration.

  2. Measurement of the velocity of neutrinos from the CNGS beam with the large volume detector.

    PubMed

    Agafonova, N Yu; Aglietta, M; Antonioli, P; Ashikhmin, V V; Bari, G; Bertoni, R; Bressan, E; Bruno, G; Dadykin, V L; Fulgione, W; Galeotti, P; Garbini, M; Ghia, P L; Giusti, P; Kemp, E; Mal'gin, A S; Miguez, B; Molinario, A; Persiani, R; Pless, I A; Ryasny, V G; Ryazhskaya, O G; Saavedra, O; Sartorelli, G; Shakyrianova, I R; Selvi, M; Trinchero, G C; Vigorito, C; Yakushev, V F; Zichichi, A; Razeto, A

    2012-08-17

    We report the measurement of the time of flight of ∼17 GeV ν(μ) on the CNGS baseline (732 km) with the Large Volume Detector (LVD) at the Gran Sasso Laboratory. The CERN-SPS accelerator has been operated from May 10th to May 24th 2012, with a tightly bunched-beam structure to allow the velocity of neutrinos to be accurately measured on an event-by-event basis. LVD has detected 48 neutrino events, associated with the beam, with a high absolute time accuracy. These events allow us to establish the following limit on the difference between the neutrino speed and the light velocity: -3.8 × 10(-6) < (v(ν)-c)/c < 3.1 × 10(-6) (at 99% C.L.). This value is an order of magnitude lower than previous direct measurements.

  3. Floating substructure flexibility of large-volume 10MW offshore wind turbine platforms in dynamic calculations

    NASA Astrophysics Data System (ADS)

    Borg, Michael; Melchior Hansen, Anders; Bredmose, Henrik

    2016-09-01

    Designing floating substructures for the next generation of 10MW and larger wind turbines has introduced new challenges in capturing relevant physical effects in dynamic simulation tools. In achieving technically and economically optimal floating substructures, structural flexibility may increase to the extent that it becomes relevant to include in addition to the standard rigid body substructure modes which are typically described through linear radiation-diffraction theory. This paper describes a method for the inclusion of substructural flexibility in aero-hydro-servo-elastic dynamic simulations for large-volume substructures, including wave-structure interactions, to form the basis of deriving sectional loads and stresses within the substructure. The method is applied to a case study to illustrate the implementation and relevance. It is found that the flexible mode is significantly excited in an extreme event, indicating an increase in predicted substructure internal loads.

  4. Aerodynamics of the Large-Volume, Flow-Through Detector System. Final report

    SciTech Connect

    Reed, H.; Saric, W.; Laananen, D.; Martinez, C.; Carrillo, R.; Myers, J.; Clevenger, D.

    1996-03-01

    The Large-Volume Flow-Through Detector System (LVFTDS) was designed to monitor alpha radiation from Pu, U, and Am in mixed-waste incinerator offgases; however, it can be adapted to other important monitoring uses that span a number of potential markets, including site remediation, indoor air quality, radon testing, and mine shaft monitoring. Goal of this effort was to provide mechanical design information for installation of LVFTDS in an incinerator, with emphasis on ability to withstand the high temperatures and high flow rates expected. The work was successfully carried out in three stages: calculation of pressure drop through the system, materials testing to determine surrogate materials for wind-tunnel testing, and wind-tunnel testing of an actual configuration.

  5. Studies on plasma production in a large volume system using multiple compact ECR plasma sources

    NASA Astrophysics Data System (ADS)

    Tarey, R. D.; Ganguli, A.; Sahu, D.; Narayanan, R.; Arora, N.

    2017-01-01

    This paper presents a scheme for large volume plasma production using multiple highly portable compact ECR plasma sources (CEPS) (Ganguli et al 2016 Plasma Source Sci. Technol. 25 025026). The large volume plasma system (LVPS) described in the paper is a scalable, cylindrical vessel of diameter  ≈1 m, consisting of source and spacer sections with multiple CEPS mounted symmetrically on the periphery of the source sections. Scaling is achieved by altering the number of source sections/the number of sources in a source section or changing the number of spacer sections for adjusting the spacing between the source sections. A series of plasma characterization experiments using argon gas were conducted on the LVPS under different configurations of CEPS, source and spacer sections, for an operating pressure in the range 0.5-20 mTorr, and a microwave power level in the range 400-500 W per source. Using Langmuir probes (LP), it was possible to show that the plasma density (~1  -  2  ×  1011 cm-3) remains fairly uniform inside the system and decreases marginally close to the chamber wall, and this uniformity increases with an increase in the number of sources. It was seen that a warm electron population (60-80 eV) is always present and is about 0.1% of the bulk plasma density. The mechanism of plasma production is discussed in light of the results obtained for a single CEPS (Ganguli et al 2016 Plasma Source Sci. Technol. 25 025026).

  6. Rapid concentration of Bacillus and Clostridium spores from large volumes of milk, using continuous flow centrifugation.

    PubMed

    Agoston, Réka; Soni, Kamlesh A; McElhany, Katherine; Cepeda, Martha L; Zuckerman, Udi; Tzipori, Saul; Mohácsi-Farkas, Csilla; Pillai, Suresh D

    2009-03-01

    Deliberate or accidental contamination of foods such as milk, soft drinks, and drinking water with infectious agents or toxins is a major concern to health authorities. There is a critical need to develop technologies that can rapidly and efficiently separate and concentrate biothreat agents from food matrices. A key limitation of current centrifugation and filtration technologies is that they are batch processes with extensive hands-on involvement and processing times. The objective of our studies was to evaluate the continuous flow centrifugation (CFC) technique for the rapid separation and concentration of bacterial spores from large volumes of milk. We determined the effectiveness of the CFC technology for concentrating approximately 10(3) bacterial spores in 3.7 liters (1 gal) of whole milk and skim milk, using Bacillus subtilis, Bacillus atrophaeus, and Clostridium sporogenes spores as surrogates for biothreat agents. The spores in the concentrated samples were enumerated by using standard plating techniques. Three independent experiments were performed at 10,000 rpm and 0.7 liters/min flow rate. The mean B. subtilis spore recoveries were 71.3 and 56.5% in skim and whole milk, respectively, and those for B. atrophaeus were 55 and 59.3% in skim and whole milk, respectively. In contrast, mean C. sporogenes spore recoveries were 88.2 and 78.6% in skim and whole milk, respectively. The successful use of CFC to concentrate these bacterial spores from 3.7 liters of milk in 10 min shows promise for rapidly concentrating other spores from large volumes of milk.

  7. Anatomic Landmarks Versus Fiducials for Volume-Staged Gamma Knife Radiosurgery for Large Arteriovenous Malformations

    SciTech Connect

    Petti, Paula L. . E-mail: ppetti@radonc.ucsf.edu; Coleman, Joy; McDermott, Michael; Smith, Vernon; Larson, David A.

    2007-04-01

    Purpose: The purpose of this investigation was to compare the accuracy of using internal anatomic landmarks instead of surgically implanted fiducials in the image registration process for volume-staged gamma knife (GK) radiosurgery for large arteriovenous malformations. Methods and Materials: We studied 9 patients who had undergone 10 staged GK sessions for large arteriovenous malformations. Each patient had fiducials surgically implanted in the outer table of the skull at the first GK treatment. These markers were imaged on orthogonal radiographs, which were scanned into the GK planning system. For the same patients, 8-10 pairs of internal landmarks were retrospectively identified on the three-dimensional time-of-flight magnetic resonance imaging studies that had been obtained for treatment. The coordinate transformation between the stereotactic frame space for subsequent treatment sessions was then determined by point matching, using four surgically embedded fiducials and then using four pairs of internal anatomic landmarks. In both cases, the transformation was ascertained by minimizing the chi-square difference between the actual and the transformed coordinates. Both transformations were then evaluated using the remaining four to six pairs of internal landmarks as the test points. Results: Averaged over all treatment sessions, the root mean square discrepancy between the coordinates of the transformed and actual test points was 1.2 {+-} 0.2 mm using internal landmarks and 1.7 {+-} 0.4 mm using the surgically implanted fiducials. Conclusion: The results of this study have shown that using internal landmarks to determine the coordinate transformation between subsequent magnetic resonance imaging scans for volume-staged GK arteriovenous malformation treatment sessions is as accurate as using surgically implanted fiducials and avoids an invasive procedure.

  8. Large Volume Coagulation Utilizing Multiple Cavitation Clouds Generated by Array Transducer Driven by 32 Channel Drive Circuits

    NASA Astrophysics Data System (ADS)

    Nakamura, Kotaro; Asai, Ayumu; Sasaki, Hiroshi; Yoshizawa, Shin; Umemura, Shin-ichiro

    2013-07-01

    High-intensity focused ultrasound (HIFU) treatment is a noninvasive treatment, in which focused ultrasound is generated outside the body and coagulates a diseased tissue. The advantage of this method is minimal physical and mental stress to the patient, and the disadvantage is the long treatment time caused by the smallness of the therapeutic volume by a single exposure. To improve the efficiency and shorten the treatment time, we are focusing attention on utilizing cavitation bubbles. The generated microbubbles can convert the acoustic energy into heat with a high efficiency. In this study, using the class D amplifiers, which we have developed, to drive the array transducer, we demonstrate a new method to coagulate a large volume by a single HIFU exposure through generating cavitation bubbles distributing in a large volume and vibrating all of them. As a result, the coagulated volume by the proposed method was 1.71 times as large as that of the conventional method.

  9. Large-volume hot spots in gold spiky nanoparticle dimers for high-performance surface-enhanced spectroscopy.

    PubMed

    Li, Anran; Li, Shuzhou

    2014-11-07

    Hot spots with a large electric field enhancement usually come in small volumes, limiting their applications in surface-enhanced spectroscopy. Using a finite-difference time-domain method, we demonstrate that spiky nanoparticle dimers (SNPD) can provide hot spots with both large electric field enhancement and large volumes because of the pronounced lightning rod effect of spiky nanoparticles. We find that the strongest electric fields lie in the gap region when SNPD is in a tip-to-tip (T-T) configuration. The enhancement of electric fields (|E|(2)/|E0|(2)) in T-T SNPD with a 2 nm gap can be as large as 1.21 × 10(6). And the hot spot volume in T-T SNPD is almost 7 times and 5 times larger than those in the spike dimer and sphere dimer with the same gap size of 2 nm, respectively. The hot spot volume in SNPD can be further improved by manipulating the arrangements of spiky nanoparticles, where crossed T-T SNPD provides the largest hot spot volume, which is 1.5 times that of T-T SNPD. Our results provide a strategy to obtain hot spots with both intense electric fields and large volume by adding a bulky core at one end of the spindly building block in dimers.

  10. A new design for a high resolution, high efficiency CZT gamma camera detector

    NASA Astrophysics Data System (ADS)

    Mestais, C.; Baffert, N.; Bonnefoy, J. P.; Chapuis, A.; Koenig, A.; Monnet, O.; Ouvrier Buffet, P.; Rostaing, J. P.; Sauvage, F.; Verger, L.

    2001-02-01

    We have designed a CZT gamma camera detector that provides an array of CZT pixels and associated front-end electronics - including an ASIC - and permits gamma camera measurements using the method patented by CEA-LETI and reported by Verger et al. [1]. Electron response in each CZT pixel is registered by correcting pulse height for position of interaction based on fast rise-time information. This method brings advantages of high scatter rejection while allowing high detection efficiency. These techniques and the systems approach have been developed at CEA-LETI in an exclusive joint development with BICRON and CRISMATEC who in turn are commercializing the technology. The initial system is implemented in an array framework with 1920 pixels, approximately 180×215 mm 2 in dimension, but the system architecture expands readily to 4096 pixels, and these arrays can be ganged into groups of up to 8 for pixel planes totaling over 32 000 pixels without architecture changes. The overall system design is described and brain phantom images are presented that were obtained by scanning with a small number of pixels.

  11. Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods

    SciTech Connect

    H. Hermon; M. Schieber; R. B. James; E. Y. Lee; N. Yang; A. J. Antolak; D. H. Morse; C. Hackett; E. Tarver; N. N. P. Kolesnikov; Yu N. Ivanov; V. Komar; M. S. Goorsky; H. Yoon

    2000-01-10

    Sandia National Laboratories (SNL) is leading an effort to evaluate vertical high pressure Bridgman (VHPB) Cd{sub 1-x}Zn{sub x}Te (CZT) crystals grown in the former Soviet Union (FSU) (Ukraine and Russia), in order to study the parameters limiting the crystal quality and the radiation detector performance. The stoichiometry of the CZT crystals, with 0.04 < x < 0.25, has been determined by methods such as proton-induced X-ray emission (PIXE), X-ray diffraction (XRD), microprobe analysis and laser ablation ICP mass spectroscopy (LA-ICP/MS). Other methods such as triaxial double crystal x-ray diffraction (TADXRD), infrared transmission spectroscopy (IR), atomic force microscopy (AFM), thermoelectric emission spectroscopy (TEES) and laser induced transient charge technique (TCT) were also used to evaluate the material properties. The authors have measured the zinc distribution in a CZT ingot along the axial direction and also its homogeneity. The (Cd+Zn)/Te average ratio measured on the Ukraine crystals was 1.2, compared to the ratio of 0.9-1.06 on the Russian ingots. The IR transmission showed highly decorated grain boundaries with precipitates and hollow bubbles. Microprobe elemental analysis and LA-ICP/MS showed carbon precipitates in the CZT bulk and carbon deposits along grain boundaries. The higher concentration of impurities and the imperfect crystallinity lead to shorter electron and hole lifetimes in the range of 0.5--2 {micro}s and 0.1 {micro}s respectively, compared to 3--20 {micro}s and 1--7 {micro}s measured on US spectrometer grade CZT detectors. These results are consistent with the lower resistivity and worse crystalline perfection of these crystals, compared to US grown CZT. However, recently grown CZT from FSU exhibited better detector performance and good response to alpha particles.

  12. Major risk from rapid, large-volume landslides in Europe (EU Project RUNOUT)

    NASA Astrophysics Data System (ADS)

    Kilburn, Christopher R. J.; Pasuto, Alessandro

    2003-08-01

    Project RUNOUT has investigated methods for reducing the risk from large-volume landslides in Europe, especially those involving rapid rates of emplacement. Using field data from five test sites (Bad Goisern and Köfels in Austria, Tessina and Vajont in Italy, and the Barranco de Tirajana in Gran Canaria, Spain), the studies have developed (1) techniques for applying geomorphological investigations and optical remote sensing to map landslides and their evolution; (2) analytical, numerical, and cellular automata models for the emplacement of sturzstroms and debris flows; (3) a brittle-failure model for forecasting catastrophic slope failure; (4) new strategies for integrating large-area Global Positioning System (GPS) arrays with local geodetic monitoring networks; (5) methods for raising public awareness of landslide hazards; and (6) Geographic Information System (GIS)-based databases for the test areas. The results highlight the importance of multidisciplinary studies of landslide hazards, combining subjects as diverse as geology and geomorphology, remote sensing, geodesy, fluid dynamics, and social profiling. They have also identified key goals for an improved understanding of the physical processes that govern landslide collapse and runout, as well as for designing strategies for raising public awareness of landslide hazards and for implementing appropriate land management policies for reducing landslide risk.

  13. Large-volume ultralow background germanium-germanium coincidence/anticoincidence gamma-ray spectrometer

    SciTech Connect

    Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.; Avignone, F.T. III; Miley, H.S.; Moore, R.S.

    1984-03-01

    A large volume (approx. 1440 cm/sup 3/), multicrystal, high resolution intrinsic germanium gamma-ray spectrometer has been designed based on 3 generations of experiments. The background from construction materials used in standard commercial configurations has been reduced by at least two orders of magnitude. Data taken with a 132 cm/sup 3/ prototype detector, installed in the Homestake Gold Mine, are presented. The first application of the full scale detector will be an ultrasensitive search for neutrinoless and two-neutrino double beta decay of /sup 76/Ge. The size and geometrical configuration of the crystals is chosen to optimize detection of double decay to the first excited state of /sup 76/Se with subsequent emission of a 559 keV gamma ray. The detector will be sufficiently sensitive for measuring the neutrinoless double beta decay to the ground state to establish a minimum half life of 1.4.10/sup 24/ y. Application of the large spectrometer system to the analysis of low level environmental and biological samples is discussed.

  14. Optimal energy window selection of a CZT-based small-animal SPECT for quantitative accuracy

    NASA Astrophysics Data System (ADS)

    Park, Su-Jin; Yu, A. Ram; Choi, Yun Young; Kim, Kyeong Min; Kim, Hee-Joung

    2015-05-01

    Cadmium zinc telluride (CZT)-based small-animal single-photon emission computed tomography (SPECT) has desirable characteristics such as superior energy resolution, but data acquisition for SPECT imaging has been widely performed with a conventional energy window. The aim of this study was to determine the optimal energy window settings for technetium-99 m (99mTc) and thallium-201 (201Tl), the most commonly used isotopes in SPECT imaging, using CZT-based small-animal SPECT for quantitative accuracy. We experimentally investigated quantitative measurements with respect to primary count rate, contrast-to-noise ratio (CNR), and scatter fraction (SF) within various energy window settings using Triumph X-SPECT. The two ways of energy window settings were considered: an on-peak window and an off-peak window. In the on-peak window setting, energy centers were set on the photopeaks. In the off-peak window setting, the ratios of energy differences between the photopeak from the lower- and higher-threshold varied from 4:6 to 3:7. In addition, the energy-window width for 99mTc varied from 5% to 20%, and that for 201Tl varied from 10% to 30%. The results of this study enabled us to determine the optimal energy windows for each isotope in terms of primary count rate, CNR, and SF. We selected the optimal energy window that increases the primary count rate and CNR while decreasing SF. For 99mTc SPECT imaging, the energy window of 138-145 keV with a 5% width and off-peak ratio of 3:7 was determined to be the optimal energy window. For 201Tl SPECT imaging, the energy window of 64-85 keV with a 30% width and off-peak ratio of 3:7 was selected as the optimal energy window. Our results demonstrated that the proper energy window should be carefully chosen based on quantitative measurements in order to take advantage of desirable characteristics of CZT-based small-animal SPECT. These results provided valuable reference information for the establishment of new protocol for CZT

  15. The oligocene Lund Tuff, Great Basin, USA: A very large volume monotonous intermediate

    USGS Publications Warehouse

    Maughan, L.L.; Christiansen, E.H.; Best, M.G.; Gromme, C.S.; Deino, A.L.; Tingey, D.G.

    2002-01-01

    Unusual monotonous intermediate ignimbrites consist of phenocryst-rich dacite that occurs as very large volume (> 1000 km3) deposits that lack systematic compositional zonation, comagmatic rhyolite precursors, and underlying plinian beds. They are distinct from countless, usually smaller volume, zoned rhyolite-dacite-andesite deposits that are conventionally believed to have erupted from magma chambers in which thermal and compositional gradients were established because of sidewall crystallization and associated convective fractionation. Despite their great volume, or because of it, monotonous intermediates have received little attention. Documentation of the stratigraphy, composition, and geologic setting of the Lund Tuff - one of four monotonous intermediate tuffs in the middle-Tertiary Great Basin ignimbrite province - provides insight into its unusual origin and, by implication, the origin of other similar monotonous intermediates. The Lund Tuff is a single cooling unit with normal magnetic polarity whose volume likely exceeded 3000 km3. It was emplaced 29.02 ?? 0.04 Ma in and around the coeval White Rock caldera which has an unextended north-south diameter of about 50 km. The tuff is monotonous in that its phenocryst assemblage is virtually uniform throughout the deposit: plagioclase > quartz ??? hornblende > biotite > Fe-Ti oxides ??? sanidine > titanite, zircon, and apatite. However, ratios of phenocrysts vary by as much as an order of magnitude in a manner consistent with progressive crystallization in the pre-eruption chamber. A significant range in whole-rock chemical composition (e.g., 63-71 wt% SiO2) is poorly correlated with phenocryst abundance. These compositional attributes cannot have been caused wholly by winnowing of glass from phenocrysts during eruption, as has been suggested for the monotonous intermediate Fish Canyon Tuff. Pumice fragments are also crystal-rich, and chemically and mineralogically indistinguishable from bulk tuff. We

  16. Hematopoietic progenitor cell large volume leukapheresis (LVL) on the Fenwal Amicus blood separator.

    PubMed

    Burgstaler, Edwin A; Pineda, Alvaro A; Winters, Jeffrey L

    2004-01-01

    A technique for large volume leukapheresis (LVL) for hematopoietic progenitor cell (HPC) collection using the Fenwal Amicus is presented. It was compared to standard collections (STD) with regard to CD34+ cell yields and cross-cellular content. Optimal cycle volumes and machine settings were evaluated for LVL procedures. A total of 68 patients underwent 80 HPC collection procedures. Because of differences in CD34+ cell yields associated with peripheral white blood cell counts (WBC), the comparison was divided into groups of 20 with WBC < or =35 x 10(9)/L (< or =35 K) and those >35 x 10(9)/L (>35 K). Baseline CD34+ cell counts (peripheral count when patient started HPC collection) were used (median 18-23 cells/microl). Significantly more whole blood (corrected for anticoagulant) was processed with LVL (LVL 20 l vs. STD 13.5 l). For < or =35 K, median CD34+ x 10(6), WBC x 10(9), RBC ml, Plt x 10(11) yields/collection were 183, 21.2, 14, 0.8, respectively, for STD vs. 307, 22.1, 11, 1.0, respectively, for LVL. For >35 K, median CD34+ x 10(6), WBC x 10(9), RBC ml, Plt x 10(11) yields/collection were 189, 32.7, 15, 1.4, respectively, for STD vs. 69, 40.8, 21, 1.3, respectively, for LVL. We have described a method of LVL using the Amicus that, in patients with pre-procedure WBC < or =35 x 10(9)/L, collects more CD34+ cells than a standard procedure with acceptable cross-cellular content. This method is not recommended when pre-procedure WBC counts are >35 x 10(9)/L.

  17. Storage and eruption of large volumes of rhyolite lava: Example from Solfatara Plateau, Yellowstone Caldera

    NASA Astrophysics Data System (ADS)

    Befus, K.; Gardner, J. E.; Zinke, R.

    2010-12-01

    The cataclysmic volcanic history of Yellowstone caldera has been extensively documented in both popular media and scholarly journals. High-silica magmas should erupt explosively because of their high viscosity and volatile content; however, numerous passively-erupted, large-volume rhyolite lava flows have also erupted from Yellowstone caldera. We use petrologic observations of one such flow, the Solfatara Plateau obsidian lava, to provide insights into the eruptive dynamics and pre-eruptive magmatic conditions of large-volume rhyolite lava. Solfatara Plateau, a 7 km3 high-silica rhyolite lava that extends 4-15 km from vent, erupted 103±8 ka within the Yellowstone caldera1. Quartz and sanidine are the dominant phenocrysts, with crystal contents of 5-10% throughout. FTIR analyses of glass inclusions in quartz and sanidine phenocrysts indicate that pre-eruptive dissolved volatile contents were up to 3.0 wt. % H2O and 250 ppm CO2. Myrmekite blebs partially envelop quartz and sanidine phenocrysts in all samples from along the margins of the flow (up to 3 km from flow front). Sanidines in samples from near vent are unzoned at Or49±2. Those at the flow front have similar cores, but rims are more sodic (Or44±6). Alkali feldspars in myrmekite range from Or27 to Or50. Petrologic observations, such as heavily embayed quartz phenocrysts and dissolution of myrmekite indicate disequilibrium within the system, likely as a result of significant heating that caused portions of the magma body to go from near-solidus to near-liquidus conditions prior to erupting. When it did erupt, volatile loss during eruptive ascent led to undercooling and significant microlite crystallization of Fe-Ti oxide and clinopyroxene microlites. Fe-Ti microlites occur as roughly equidimensional crystals, 1-10 µm across, as well as high-aspect-ratio needles, 3-60 µm long. Clinopyroxene microlites occur primarily as individual prismatic crystals, but also occur as linked, curved chains or as overgrowths

  18. Physiological and Psychological Changes Following Liposuction of Large Volumes of Fat in Overweight and Obese Women

    PubMed Central

    Geliebter, Allan; Krawitz, Emily; Ungredda, Tatiana; Peresechenski, Ella; Giese, Sharon Y.

    2016-01-01

    Background Liposuction can remove a substantial amount of body fat. We investigated the effects of liposuction of large volumes of fat on anthropometrics, body composition (BIA), metabolic hormones, and psychological measures in overweight/obese women. To our knowledge, this is the first study to examine both physiological and psychological changes following liposuction of large volumes of fat in humans. Method Nine premenopausal healthy overweight/obese women (age = 35.9 ± 7.1 SD, weight = 84.4 kg ± 13.6, BMI = 29.9 kg/m2 ± 2.9) underwent liposuction, removing 3.92 kg ± 1.04 SD of fat. Following an overnight fast, height, weight, waist, and hip circumferences were measured at baseline (one week pre-surgery) and post-surgery (wk 1,4,12). Blood samples were drawn for fasting concentrations of glucose, insulin, leptin, and ghrelin. The Body Shape Questionnaire (BSQ), Body Dysmorphic Disorder (BDD) Examination Self-Report (BDDE-SR), and Zung Self-Rating Depression Scale (ZDS) were administered. Results Body weight, BMI, waist circumference, and body fat consistently decreased over time (p < .05). Glucose did not change significantly, but insulin decreased from wk 1 to wk 12 (p < .05). Leptin decreased from baseline to wk 1 (p = .01); ghrelin increased but not significantly. Changes in body fat and waist circumference (baseline to wk 1) correlated positively with changes in insulin during that period, and correlated inversely with changes in ghrelin (p < .05). BSQ scores decreased significantly over time (p = .004), but scores for BDDE-SR (p = .10) and ZDS (p = .24) did not change significantly. Conclusion Liposuction led to significant decreases in body weight and fat, waist circumference, and leptin levels. Changes in body fat and waist circumference correlated with concurrent changes in the adipose-related hormones, insulin and ghrelin (baseline to wk 1), and body shape perception improved. Thus, besides the obvious cosmetic effects, liposuction led to several

  19. A simple method for the production of large volume 3D macroporous hydrogels for advanced biotechnological, medical and environmental applications

    PubMed Central

    Savina, Irina N.; Ingavle, Ganesh C.; Cundy, Andrew B.; Mikhalovsky, Sergey V.

    2016-01-01

    The development of bulk, three-dimensional (3D), macroporous polymers with high permeability, large surface area and large volume is highly desirable for a range of applications in the biomedical, biotechnological and environmental areas. The experimental techniques currently used are limited to the production of small size and volume cryogel material. In this work we propose a novel, versatile, simple and reproducible method for the synthesis of large volume porous polymer hydrogels by cryogelation. By controlling the freezing process of the reagent/polymer solution, large-scale 3D macroporous gels with wide interconnected pores (up to 200 μm in diameter) and large accessible surface area have been synthesized. For the first time, macroporous gels (of up to 400 ml bulk volume) with controlled porous structure were manufactured, with potential for scale up to much larger gel dimensions. This method can be used for production of novel 3D multi-component macroporous composite materials with a uniform distribution of embedded particles. The proposed method provides better control of freezing conditions and thus overcomes existing drawbacks limiting production of large gel-based devices and matrices. The proposed method could serve as a new design concept for functional 3D macroporous gels and composites preparation for biomedical, biotechnological and environmental applications. PMID:26883390

  20. A simple method for the production of large volume 3D macroporous hydrogels for advanced biotechnological, medical and environmental applications

    NASA Astrophysics Data System (ADS)

    Savina, Irina N.; Ingavle, Ganesh C.; Cundy, Andrew B.; Mikhalovsky, Sergey V.

    2016-02-01

    The development of bulk, three-dimensional (3D), macroporous polymers with high permeability, large surface area and large volume is highly desirable for a range of applications in the biomedical, biotechnological and environmental areas. The experimental techniques currently used are limited to the production of small size and volume cryogel material. In this work we propose a novel, versatile, simple and reproducible method for the synthesis of large volume porous polymer hydrogels by cryogelation. By controlling the freezing process of the reagent/polymer solution, large-scale 3D macroporous gels with wide interconnected pores (up to 200 μm in diameter) and large accessible surface area have been synthesized. For the first time, macroporous gels (of up to 400 ml bulk volume) with controlled porous structure were manufactured, with potential for scale up to much larger gel dimensions. This method can be used for production of novel 3D multi-component macroporous composite materials with a uniform distribution of embedded particles. The proposed method provides better control of freezing conditions and thus overcomes existing drawbacks limiting production of large gel-based devices and matrices. The proposed method could serve as a new design concept for functional 3D macroporous gels and composites preparation for biomedical, biotechnological and environmental applications.

  1. Photoperiod is associated with hippocampal volume in a large community sample.

    PubMed

    Miller, Megan A; Leckie, Regina L; Donofry, Shannon D; Gianaros, Peter J; Erickson, Kirk I; Manuck, Stephen B; Roecklein, Kathryn A

    2015-04-01

    Although animal research has demonstrated seasonal changes in hippocampal volume, reflecting seasonal neuroplasticity, seasonal differences in human hippocampal volume have yet to be documented. Hippocampal volume has also been linked to depressed mood, a seasonally varying phenotype. Therefore, we hypothesized that seasonal differences in day-length (i.e., photoperiod) would predict differences in hippocampal volume, and that this association would be linked to low mood. Healthy participants aged 30-54 (M=43; SD=7.32) from the University of Pittsburgh Adult Health and Behavior II project (n=404; 53% female) were scanned in a 3T MRI scanner. Hippocampal volumes were determined using an automated segmentation algorithm using FreeSurfer. A mediation model tested whether hippocampal volume mediated the relationship between photoperiod and mood. Secondary analyses included seasonally fluctuating variables (i.e., sleep and physical activity) which have been shown to influence hippocampal volume. Shorter photoperiods were significantly associated with higher BDI scores (R(2)=0.01, β=-0.12, P=0.02) and smaller hippocampal volumes (R(2)=0.40, β=0.08, P=0.04). However, due to the lack of an association between hippocampal volume and Beck Depression Inventory scores in the current sample, the mediation hypothesis was not supported. This study is the first to demonstrate an association between season and hippocampal volume. These data offer preliminary evidence that human hippocampal plasticity could be associated with photoperiod and indicates a need for longitudinal studies.

  2. Radiometric Dating of Large Volume Flank Collapses in The Lesser Antilles Arc.

    NASA Astrophysics Data System (ADS)

    Quidelleur, X.; Samper, A.; Boudon, G.; Le Friant, A.; Komorowski, J.

    2004-12-01

    It is now admitted that flank collapses, probably triggered by magmatic inflation and/or gravitational collapses, is a recurrent process of the evolution of the Lesser Antilles Arc volcanoes. Large magnitude debris avalanche deposits have been identified offshore, in the Grenada basin (Deplus et al., 2001; Le Friant et al., 2001). The widest extensions have been observed off the coast of Dominica and St Lucia, with associated volumes up to 20 km3. Another large-scale event, with marine evidences probably covered by sediments and latter flank collapses, has been inferred onland from morphological evidences and characteristic deposits of the Carbets structure in Martinique. We present radiometric dating of these three major events using the K-Ar Cassignol-Gillot technique performed on selected groundmass. Both volcanic formations preceding flank collapses (remnants of the horseshoe shaped structures or basal lava flows) and following landslides (lava domes) have been dated. In the Qualibou depression of St. Lucia, the former structure has been dated at 1096+-16 ka and the collapse constrained by dome emplacement prior to 97+-2 ka (Petit Piton). In Dominica, several structures have been associated with repetitive flank collapse events inferred from marine data (Le Friant et al., 2002). The Plat-Pays event probably occurred after 96+-2 ka. Inside the inherited depression, Scotts Head, which is interpreted as a proximal pluri-kilometric megabloc from the Soufriere avalanche, has been dated at 14+-1 ka, providing an older bound for this event. In Martinique Island, three different domes within the Carbets structure have been dated at 335+-5 ka. Assuming a rapid magma emplacement following pressure release due to deloading, this constrains the age of this high magnitude event. Finally, these results obtained from three of the most voluminous flank collapses provide constraints to estimate the recurrence of these events, which represent one of the major hazards associated

  3. Radiometric dating of three large volume flank collapses in the Lesser Antilles Arc

    NASA Astrophysics Data System (ADS)

    Samper, A.; Quidelleur, X.; Boudon, G.; Le Friant, A.; Komorowski, J. C.

    2008-10-01

    It is now recognised that flank collapses are a recurrent process in the evolution of the Lesser Antilles Arc volcanoes. Large magnitude debris-avalanche deposits have been identified off the coast of Dominica, Martinique and St. Lucia, with associated volumes up to 20 km 3 [Deplus, C., Le Friant, A., Boudon, G., Komorowski, J.-C., Villemant, B., Harford, C., Ségoufin, J., Cheminée, J.-L., 2001. Submarine evidence for large-scale debris avalanches in the Lesser Antilles Arc. Earth Planet. Sci. Lett., 192: 145-157.]. We present new radiometric dating of three major events using the K-Ar Cassignol-Gillot technique. In the Qualibou depression of St. Lucia, a collapse has been constrained by dome emplacement prior to 95 ± 2 ka. In Dominica, where repetitive flank collapse events have occurred [Le Friant, A., Boudon, G., Komorowski, J.-C., Deplus, C., 2002. L'île de la Dominique, à l'origine des avalanches de débris les plus volumineuses de l'arc des Petites Antilles. C.R. Geoscience, 334: 235-243], the Plat Pays event probably occurred after 96 ± 2 ka. Inside the depression caused by this event, Scotts Head, which is interpreted as a proximal megabloc from the subsequent Soufriere avalanche event has been dated at 14 ± 1 ka, providing an older bound for this event. On Martinique three different domes within the Carbets structure dated at 337 ± 5 ka constrain the age of this high magnitude event. Finally, these results obtained from three of the most voluminous flank collapses provide constraints to estimate the recurrence of these events, which represent one of the major hazards associated with volcanoes of the Lesser Antilles Arc.

  4. Curling probe measurement of a large-volume pulsed plasma with surface magnetic confinement

    NASA Astrophysics Data System (ADS)

    Pandey, A.; Tashiro, H.; Sakakibara, W.; Nakamura, K.; Sugai, H.

    2016-12-01

    A curling probe (CP) based on microwave resonance is applied to the measurement of electron density in a pulsed DC glow discharge under surface magnetic confinement (SMC) provided by a number of permanent magnets on a chamber wall. Owing to the SMC effects, a 1 m scale large-volume plasma is generated by a relatively low voltage (~1 kV) at low pressure (~1 Pa) in various gases (Ar, CH4, and C2H2). Temporal variation of the electron density is measured for pulse frequency f  =  0.5-25 kHz for various discharge-on times (T ON) with a high resolution time (~0.2 µs), using the on-point mode. In general, the electron density starts to increase at time t  =  0 after turn-on of the discharge voltage, reaches peak density at t  =  T ON, and then decreases after turn-off. The peak electron density is observed to increase with the pulse frequency f for constant T ON owing to the residual plasma. This dependence is successfully formulated using a semi-empirical model. The spatio-temporal evolution of the cathode sheath in the pulsed discharge is revealed by a 1 m long movable CP. The measured thickness of the high-voltage cathode fall in a steady state coincides with the value of the so-called Child-Langmuir sheath.

  5. High-Dimensional Function Approximation With Neural Networks for Large Volumes of Data.

    PubMed

    Andras, Peter

    2017-01-25

    Approximation of high-dimensional functions is a challenge for neural networks due to the curse of dimensionality. Often the data for which the approximated function is defined resides on a low-dimensional manifold and in principle the approximation of the function over this manifold should improve the approximation performance. It has been show that projecting the data manifold into a lower dimensional space, followed by the neural network approximation of the function over this space, provides a more precise approximation of the function than the approximation of the function with neural networks in the original data space. However, if the data volume is very large, the projection into the low-dimensional space has to be based on a limited sample of the data. Here, we investigate the nature of the approximation error of neural networks trained over the projection space. We show that such neural networks should have better approximation performance than neural networks trained on high-dimensional data even if the projection is based on a relatively sparse sample of the data manifold. We also find that it is preferable to use a uniformly distributed sparse sample of the data for the purpose of the generation of the low-dimensional projection. We illustrate these results considering the practical neural network approximation of a set of functions defined on high-dimensional data including real world data as well.

  6. Development testing of large volume water sprays for warm fog dispersal

    NASA Technical Reports Server (NTRS)

    Keller, V. W.; Anderson, B. J.; Burns, R. A.; Lala, G. G.; Meyer, M. B.; Beard, K. V.

    1986-01-01

    A new brute-force method of warm fog dispersal is described. The method uses large volume recycled water sprays to create curtains of falling drops through which the fog is processed by the ambient wind and spray induced air flow. Fog droplets are removed by coalescence/rainout. The efficiency of the technique depends upon the drop size spectra in the spray, the height to which the spray can be projected, the efficiency with which fog laden air is processed through the curtain of spray, and the rate at which new fog may be formed due to temperature differences between the air and spray water. Results of a field test program, implemented to develop the data base necessary to assess the proposed method, are presented. Analytical calculations based upon the field test results indicate that this proposed method of warm fog dispersal is feasible. Even more convincingly, the technique was successfully demonstrated in the one natural fog event which occurred during the test program. Energy requirements for this technique are an order of magnitude less than those to operate a thermokinetic system. An important side benefit is the considerable emergency fire extinguishing capability it provides along the runway.

  7. Multi-stage polymer systems for the autonomic regeneration of large damage volumes

    NASA Astrophysics Data System (ADS)

    Santa Cruz, Windy Ann

    Recovery of catastrophic damage requires a robust chemistry capable of addressing the complex challenges encountered by autonomic regeneration. Although self-healing polymers have the potential to increase material lifetimes and safety, these systems have been limited to recovery of internal microcracks and surface damage. Current technologies thereby fail to address the restoration of large, open damage volumes. A regenerative chemistry was developed by incorporating a gel scaffold within liquid healing agents. The healing system undergoes two stages, sol-gel and gel-polymer. Stage 1, rapid formation of a crosslinked gel, creates a synthetic support for the healing agents as they deposit across the damage region. Stage 2 comprises the polymerization of monomer using a room temperature redox initiation system to recover the mechanical properties of the substrate. The two stages are chemically compatible and only react when a specific reaction trigger is introduced -- an acid catalyst for gelation and initiator-promoter for polymerization. Cure kinetics, chemical and mechanical properties can be tuned by employing different monomer systems. The versatile gelation chemistry gels over 20 vinyl monomers to yield both thermoplastic and thermosetting polymers. The healing efficacy of the two-stage system was studied in thin, vascularized epoxy sheets. By splitting the chemistry into two low viscosity fluids, we demonstrated regeneration of gaps up to 9 mm in diameter. The combination of microvascular networks and a new healing chemistry demonstrates an innovative healing system that significantly exceeds the performance of traditional methods.

  8. Detecting Boosted Dark Matter from the Sun with Large Volume Neutrino Detectors

    SciTech Connect

    Berger, Joshua; Cui, Yanou; Zhao, Yue; /Stanford U., ITP /Stanford U., Phys. Dept.

    2015-04-02

    We study novel scenarios where thermal dark matter (DM) can be efficiently captured in the Sun and annihilate into boosted dark matter. In models with semi-annihilating DM, where DM has a non-minimal stabilization symmetry, or in models with a multi-component DM sector, annihilations of DM can give rise to stable dark sector particles with moderate Lorentz boosts. We investigate both of these possibilities, presenting concrete models as proofs of concept. Both scenarios can yield viable thermal relic DM with masses O(1)-O(100) GeV. Taking advantage of the energetic proton recoils that arise when the boosted DM scatters off matter, we propose a detection strategy which uses large volume terrestrial detectors, such as those designed to detect neutrinos or proton decays. In particular, we propose a search for proton tracks pointing towards the Sun. We focus on signals at Cherenkov-radiation-based detectors such as Super-Kamiokande (SK) and its upgrade Hyper-Kamiokande (HK). We find that with spin-dependent scattering as the dominant DM-nucleus interaction at low energies, boosted DM can leave detectable signals at SK or HK, with sensitivity comparable to DM direct detection experiments while being consistent with current constraints. Our study provides a new search path for DM sectors with non-minimal structure.

  9. Detecting boosted dark matter from the Sun with large volume neutrino detectors

    SciTech Connect

    Berger, Joshua; Cui, Yanou; Zhao, Yue E-mail: ycui@perimeterinstitute.ca

    2015-02-01

    We study novel scenarios where thermal dark matter (DM) can be efficiently captured in the Sun and annihilate into boosted dark matter. In models with semi-annihilating DM, where DM has a non-minimal stabilization symmetry, or in models with a multi-component DM sector, annihilations of DM can give rise to stable dark sector particles with moderate Lorentz boosts. We investigate both of these possibilities, presenting concrete models as proofs of concept. Both scenarios can yield viable thermal relic DM with masses O(1)-O(100) GeV. Taking advantage of the energetic proton recoils that arise when the boosted DM scatters off matter, we propose a detection strategy which uses large volume terrestrial detectors, such as those designed to detect neutrinos or proton decays. In particular, we propose a search for proton tracks pointing towards the Sun. We focus on signals at Cherenkov-radiation-based detectors such as Super-Kamiokande (SK) and its upgrade Hyper-Kamiokande (HK). We find that with spin-dependent scattering as the dominant DM-nucleus interaction at low energies, boosted DM can leave detectable signals at SK or HK, with sensitivity comparable to DM direct detection experiments while being consistent with current constraints. Our study provides a new search path for DM sectors with non-minimal structure.

  10. Configuration Analysis of the ERS Points in Large-Volume Metrology System.

    PubMed

    Jin, Zhangjun; Yu, Cijun; Li, Jiangxiong; Ke, Yinglin

    2015-09-22

    In aircraft assembly, multiple laser trackers are used simultaneously to measure large-scale aircraft components. To combine the independent measurements, the transformation matrices between the laser trackers' coordinate systems and the assembly coordinate system are calculated, by measuring the enhanced referring system (ERS) points. This article aims to understand the influence of the configuration of the ERS points that affect the transformation matrix errors, and then optimize the deployment of the ERS points to reduce the transformation matrix errors. To optimize the deployment of the ERS points, an explicit model is derived to estimate the transformation matrix errors. The estimation model is verified by the experiment implemented in the factory floor. Based on the proposed model, a group of sensitivity coefficients are derived to evaluate the quality of the configuration of the ERS points, and then several typical configurations of the ERS points are analyzed in detail with the sensitivity coefficients. Finally general guidance is established to instruct the deployment of the ERS points in the aspects of the layout, the volume size and the number of the ERS points, as well as the position and orientation of the assembly coordinate system.

  11. Curling probe measurement of large-volume pulsed plasma confined by surface magnetic field

    NASA Astrophysics Data System (ADS)

    Pandey, Anil; Sakakibara, Wataru; Matsuoka, Hiroyuki; Nakamura, Keiji; Sugai, Hideo; Chubu University Team; DOWA Thermotech Collaboration

    2015-09-01

    Curling probe (CP) has recently been developed which enables the local electron density measurement even in plasma for non-conducting film CVD. The electron density is obtained from a shift of resonance frequency of spiral antenna in discharge ON and OFF monitored by a network analyzer (NWA). In case of a pulsed glow discharge, synchronization of discharge pulse with frequency sweep of NWA must be established. In this paper, we report time and space-resolved CP measurement of electron density in a large volume plasma (80 cm diameter, 110 cm length) confined by surface magnetic field (multipole cusp field ~0.03 T). For plasma-aided modification of metal surface, the plasma is produced by 1 kV glow discharge at pulse frequency of 0.3 - 25 kHz with various duty ratio in gas (Ar, N2, C2H2) at pressure ~ 1 Pa. A radially movable CP revealed a remarkable effect of surface magnetic confinement: detach of plasma from the vessel wall and a fairly uniform plasma in the central region. In afterglow phase, the electron density was observed to decrease much faster in C2H2 discharge than in Ar discharge.

  12. A new large-volume metal reference standard for radioactive waste management

    PubMed Central

    Tzika, F.; Hult, M.; Stroh, H.; Marissens, G.; Arnold, D.; Burda, O.; Kovář, P.; Suran, J.; Listkowska, A.; Tyminski, Z.

    2016-01-01

    A new large-volume metal reference standard has been developed. The intended use is for calibration of free-release radioactivity measurement systems and is made up of cast iron tubes placed inside a box of the size of a Euro-pallet (80 × 120 cm). The tubes contain certified activity concentrations of 60Co (0.290±0.006 Bq g−1) and 110mAg (3.05±0.09 Bq g−1) (reference date: 30 September 2013). They were produced using centrifugal casting from a smelt into which 60Co was first added and then one piece of neutron irradiated silver wire was progressively diluted. The iron castings were machined to the desirable dimensions. The final material consists of 12 iron tubes of 20 cm outer diameter, 17.6 cm inner diameter, 40 cm length/height and 245.9 kg total mass. This paper describes the reference standard and the process of determining the reference activity values. PMID:25977349

  13. A new large-volume metal reference standard for radioactive waste management.

    PubMed

    Tzika, F; Hult, M; Stroh, H; Marissens, G; Arnold, D; Burda, O; Kovář, P; Suran, J; Listkowska, A; Tyminski, Z

    2016-03-01

    A new large-volume metal reference standard has been developed. The intended use is for calibration of free-release radioactivity measurement systems and is made up of cast iron tubes placed inside a box of the size of a Euro-pallet (80 × 120 cm). The tubes contain certified activity concentrations of (60)Co (0.290 ± 0.006 Bq g(-1)) and (110m)Ag (3.05 ± 0.09 Bq g(-1)) (reference date: 30 September 2013). They were produced using centrifugal casting from a smelt into which (60)Co was first added and then one piece of neutron irradiated silver wire was progressively diluted. The iron castings were machined to the desirable dimensions. The final material consists of 12 iron tubes of 20 cm outer diameter, 17.6 cm inner diameter, 40 cm length/height and 245.9 kg total mass. This paper describes the reference standard and the process of determining the reference activity values.

  14. Twinning in vapour-grown, large volume Cd1-xZnxTe crystals

    NASA Astrophysics Data System (ADS)

    Tanner, B. K.; Mullins, J. T.; Pym, A. T. G.; Maneuski, D.

    2016-08-01

    The onset of twinning from (2 bar 1 bar 1 bar) to (1 bar 3 bar 3 bar) in large volume Cd1-xZnxTe crystals, grown by vapour transport on (2 bar 1 bar 1 bar) , often referred to as (211)B, oriented GaAs seeds, has been investigated using X-ray diffraction imaging (X-ray topography). Twinning is not associated with strains at the GaAs/CdTe interface as the initial growth was always in (2 bar 1 bar 1 bar) orientation. Nor is twinning related to lattice strains associated with injection of Zn subsequent to initial nucleation and growth of pure CdTe as in both cases twinning occurred after growth of several mm length of Cd1-xZnxTe. While in both cases examined, there was a region of disturbed growth prior to the twinning transition, in neither crystal does this strain appear to have nucleated the twinning process. In both cases, un-twinned material remained after twinning was observed, the scale of the resulting twin boundaries being sub-micron. Simultaneous twinning across the whole sample surface was observed in one sample, whereas in the other, twinning was nucleated at different points and times in the growth.

  15. A uniform laminar air plasma plume with large volume excited by an alternating current voltage

    NASA Astrophysics Data System (ADS)

    Li, Xuechen; Bao, Wenting; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

    2015-12-01

    Using a plasma jet composed of two needle electrodes, a laminar plasma plume with large volume is generated in air through an alternating current voltage excitation. Based on high-speed photography, a train of filaments is observed to propagate periodically away from their birth place along the gas flow. The laminar plume is in fact a temporal superposition of the arched filament train. The filament consists of a negative glow near the real time cathode, a positive column near the real time anode, and a Faraday dark space between them. It has been found that the propagation velocity of the filament increases with increasing the gas flow rate. Furthermore, the filament lifetime tends to follow a normal distribution (Gaussian distribution). The most probable lifetime decreases with increasing the gas flow rate or decreasing the averaged peak voltage. Results also indicate that the real time peak current decreases and the real time peak voltage increases with the propagation of the filament along the gas flow. The voltage-current curve indicates that, in every discharge cycle, the filament evolves from a Townsend discharge to a glow one and then the discharge quenches. Characteristic regions including a negative glow, a Faraday dark space, and a positive column can be discerned from the discharge filament. Furthermore, the plasma parameters such as the electron density, the vibrational temperature and the gas temperature are investigated based on the optical spectrum emitted from the laminar plume.

  16. Peak distortions arising from large-volume injections in supercritical fluid chromatography.

    PubMed

    Dai, Yun; Li, Geng; Rajendran, Arvind

    2015-05-01

    Preparative separations in supercritical fluid chromatography (SFC) involve the injection of large volumes of the solute. In SFC, the mobile phase is typically high pressure CO2+modifier and the solute to be injected is usually dissolved in the modifier. Two-types of injection methods, modifier-stream and mixed-stream, are common in commercial preparative SFC systems. In modifier-stream injection, the injection is made in the modifier stream which is later mixed with the CO2 stream, while in the mixed-stream injection, the injection is made in a mixed CO2+modifier stream. In this work a systematic experimental and modelling study of the two techniques is reported using single-enantiomers of flurbiprofen on Chiralpak AD-H with CO2+methanol as the mobile phase. While modifier-stream injection shows non-distorted peaks, mixed-stream injection results in severe peak-distortion. By comparing the modelling and experimental results, it is shown that the modifier "plug" introduced in the mixed-stream injection is the primary cause of the peak distortions. The experimental results also point to the possible existence of viscous fingering which contributes to further peak distortion.

  17. Development of a large mosaic volume phase holographic (VPH) grating for APOGEE

    NASA Astrophysics Data System (ADS)

    Arns, James; Wilson, John C.; Skrutskie, Mike; Smee, Steve; Barkhouser, Robert; Eisenstein, Daniel; Gunn, Jim; Hearty, Fred; Harding, Al; Maseman, Paul; Holtzman, Jon; Schiavon, Ricardo; Gillespie, Bruce; Majewski, Steven

    2010-07-01

    Volume phase holographic (VPH) gratings are increasingly being used as diffractive elements in astronomical instruments due to their potential for very high peak diffraction efficiencies and the possibility of a compact instrument design when the gratings are used in transmission. Historically, VPH grating (VPHG) sizes have been limited by the size of manufacturer's holographic recording optics. We report on the design, specification and fabrication of a large, 290 mm × 475 mm elliptically-shaped, mosaic VPHG for the Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph. This high-resolution near-infrared multi-object spectrograph is in construction for the Sloan Digital Sky Survey III (SDSS III). The 1008.6 lines/mm VPHG was designed for optimized performance over a wavelength range from 1.5 to 1.7 μm. A step-and-repeat exposure method was chosen to fabricate a three-segment mosaic on a 305 mm × 508 mm monolithic fused-silica substrate. Specification considerations imposed on the VPHG to assure the mosaic construction will satisfy the end use requirements are discussed. Production issues and test results of the mosaic VPHG are discussed.

  18. Plasma response to electron energy filter in large volume plasma device

    SciTech Connect

    Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.

    2013-12-15

    An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma.

  19. On `light' fermions and proton stability in `big divisor' D3/ D7 large volume compactifications

    NASA Astrophysics Data System (ADS)

    Misra, Aalok; Shukla, Pramod

    2011-06-01

    Building on our earlier work (Misra and Shukla, Nucl. Phys. B 827:112, 2010; Phys. Lett. B 685:347-352, 2010), we show the possibility of generating "light" fermion mass scales of MeV-GeV range (possibly related to the first two generations of quarks/leptons) as well as eV (possibly related to first two generations of neutrinos) in type IIB string theory compactified on Swiss-Cheese orientifolds in the presence of a mobile space-time filling D3-brane restricted to (in principle) stacks of fluxed D7-branes wrapping the "big" divisor Σ B . This part of the paper is an expanded version of the latter half of Sect. 3 of a published short invited review (Misra, Mod. Phys. Lett. A 26:1, 2011) written by one of the authors [AM]. Further, we also show that there are no SUSY GUT-type dimension-five operators corresponding to proton decay, and we estimate the proton lifetime from a SUSY GUT-type four-fermion dimension-six operator to be 1061 years. Based on GLSM calculations in (Misra and Shukla, Nucl. Phys. B 827:112, 2010) for obtaining the geometric Kähler potential for the "big divisor," using further the Donaldson's algorithm, we also briefly discuss in the first of the two appendices the metric for the Swiss-Cheese Calabi-Yau used, which we obtain and which becomes Ricci flat in the large-volume limit.

  20. Feasibility of large volume tumor ablation using multiple-mode strategy with fast scanning method: A numerical study

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Shen, Guofeng; Qiao, Shan; Chen, Yazhu

    2017-03-01

    Sonication with fast scanning method can generate homogeneous lesions without complex planning. But when the target region is large, switching focus too fast will reduce the heat accumulation, the margin of which may not ablated. Furthermore, high blood perfusion rate will reduce this maximum volume that can be ablated. Therefore, fast scanning method may not be applied to large volume tumor. To expand the therapy scope, this study combines the fast scan method with multiple mode strategy. Through simulation and experiment, the feasibility of this new strategy is evaluated and analyzed.

  1. Volume-dependent collection of peripheral blood progenitor cells during large-volume leukapheresis for patients with solid tumours and haematological malignancies.

    PubMed

    Cassens, U; Ostkamp-Ostermann, P; van der Werf, N; Garritsen, H; Ostermann, H; Sibrowski, W

    1999-12-01

    We investigated the efficacy of peripheral blood progenitor cell (PBPC) collection during large-volume leukapheresis (LVL) in patients with solid tumours and haematological malignancies (n = 18). The time- and volume-dependent harvest of leucocytes (WBC), mononuclear cells (MNC), CD34+ cells and colony-forming cells (CFU-GM) during LVL was analysed in six sequentially filled collection bags processing four times the patient's blood volumes. The amounts of leucocytes (WBC) and the purity of mononuclear cells (MNC%) did not show any significant changes during LVL. The percentage of CD34+ cells remained constant for the first three bags but consecutively decreased from initially 1.71% CD34+ cells in the beginning of LVL to finally 1.34% CD34+ cells (P = 0.02). The mean numbers of colony-forming cells (CFU-GM) decreased from 74 microL-1 to 59 microL-1 during LVL (P = 0.16). Furthermore, the comparison of volume-dependent PBPC collection for patients with high, medium and low total yields of CD34+ cells showed similar kinetics on different levels for the three groups. We concluded that - relative to the initial total amount of PBPC harvested - comparable numbers of progenitor cells can be collected during all stages of LVL with a slight decreasing trend processing four times the patient's blood volumes.

  2. Influence of bone volume fraction and architecture on computed large-deformation failure mechanisms in human trabecular bone.

    PubMed

    Bevill, Grant; Eswaran, Senthil K; Gupta, Atul; Papadopoulos, Panayiotis; Keaveny, Tony M

    2006-12-01

    Large-deformation bending and buckling have long been proposed as failure mechanisms by which the strength of trabecular bone can be affected disproportionately to changes in bone density, and thus may represent an important aspect of bone quality. We sought here to quantify the contribution of large-deformation failure mechanisms on strength, to determine the dependence of these effects on bone volume fraction and architecture, and to confirm that the inclusion of large-deformation effects in high-resolution finite element models improves predictions of strength versus experiment. Micro-CT-based finite element models having uniform hard tissue material properties were created from 54 cores of human trabecular bone taken from four anatomic sites (age = 70+/-11; 24 male, 27 female donors), which were subsequently biomechanically tested to failure. Strength predictions were made from the models first including, then excluding, large-deformation failure mechanisms, both for compressive and tensile load cases. As expected, strength predictions versus experimental data for the large-deformation finite element models were significantly improved (p < 0.001) relative to the small deformation models in both tension and compression. Below a volume fraction of about 0.20, large-deformation failure mechanisms decreased trabecular strength from 5-80% for compressive loading, while effects were negligible above this volume fraction. Step-wise nonlinear multiple regression revealed that structure model index (SMI) and volume fraction (BV/TV) were significant predictors of these reductions in strength (R2 = 0.83, p < 0.03). Even so, some low-density specimens having nearly identical volume fraction and SMI exhibited up to fivefold differences in strength reduction. We conclude that within very low-density bone, the potentially important biomechanical effect of large-deformation failure mechanisms on trabecular bone strength is highly heterogeneous and is not well explained by

  3. Pyrometry in the Multianvil Press: New approach for temperature measurement in large volume press experiments

    NASA Astrophysics Data System (ADS)

    Sanehira, T.; Wang, Y.; Prakapenka, V.; Rivers, M. L.

    2008-12-01

    Temperature measurement in large volume press experiments has been based on thermocouple emf, which has well known problems: unknown pressure dependence of emf [e.g., 1], chemical reaction between thermocouple and other materials, deformation related texture development in the thermocouple wires [2], and so on. Thus, different techniques to measure temperatures in large volume press experiments other than thermocouples are required to measure accurate temperatures under high pressures. Here we report a new development using pyrometry in the multianvil press, where temperatures are derived on the basis of spectral radiometry. Several high pressure runs were conducted using the 1000 ton press with a DIA module installed at 13 ID-D GSECARS beamline at Advanced Photon Source (APS) [3]. The cubic pressure medium, 14 mm edge length, was made of soft-fired pyrophyllite with a graphite furnace. A moissanite (SiC) single crystal was built inside the pressure medium as a window for the thermal emission signal to go through. An MgO disk with 1.0 mm thickness was inserted in a gap between the top of the SiC crystal and thermocouple hot junction. The bottom of the window crystal was in direct contact with the tip of the anvil, which had a 1.5 mm diameter hole drilled all the way through the anvil axis. An optical fiber was inserted in this hole and the open end of fiber was in contact with the SiC crystal. Thermal spectral radiance from the inner cell assembly was obtained via the fiber and recorded by an Ocean Optics HP2000 spectrometer. The system response of spectrometer was calibrated by a tungsten ribbon ramp (OL550S, Optronic Laboratories, Inc.) with standard of spectral radiance. The cell assembly was compressed up to target value of 15 tons and then temperature was increased up to 1573 K. Radiation spectra were mainly obtained above 873 K and typical integration time was 1 ms or 10 ms. Data collection was done in the process of increase and decrease of temperature. In

  4. Hepatic Arterial Embolization and Chemoembolization in the Management of Patients with Large-Volume Liver Metastases

    SciTech Connect

    Kamat, Paresh P.; Gupta, Sanjay Ensor, Joe E.; Murthy, Ravi; Ahrar, Kamran; Madoff, David C.; Wallace, Michael J.; Hicks, Marshall E.

    2008-03-15

    The purpose of this study was to assess the role of hepatic arterial embolization (HAE) and chemoembolization (HACE) in patients with large-volume liver metastases. Patients with metastatic neuroendocrine tumors, melanomas, or gastrointestinal stromal tumors (GISTs) with >75% liver involvement who underwent HAE or HACE were included in the study. Radiologic response, progression-free survival (PFS), overall survival (OS), and postprocedure complications were assessed. Sixty patients underwent 123 treatment sessions. Of the 48 patients for whom follow-up imaging was available, partial response was seen in 12 (25%) patients, minimal response in 6 (12%), stable disease in 22 (46%), and progressive disease in 8 (17%). Median OS and PFS were 9.3 and 4.9 months, respectively. Treatment resulted in radiologic response or disease stabilization in 82% and symptomatic response in 65% of patients with neuroendocrine tumors. Patients with neuroendocrine tumors had higher response rates (44% vs. 27% and 0%; p = 0.31) and longer PFS (9.2 vs. 2.0 and 2.3 months; p < 0.0001) and OS (17.9 vs. 2.4 and 2.3 months; p < 0.0001) compared to patients with melanomas and GISTs. Major complications occurred in 21 patients after 23 (19%) of the 123 sessions. Nine of the 12 patients who developed major complications resulting in death had additional risk factors-carcinoid heart disease, sepsis, rapidly worsening performance status, or anasarca. In conclusion, in patients with neuroendocrine tumors with >75% liver involvement, HAE/HACE resulted in symptom palliation and radiologic response or disease stabilization in the majority of patients. Patients with hepatic metastases from melanomas and GISTs, however, did not show any appreciable benefit from this procedure. Patients with massive liver tumor burden, who have additional risk factors, should not be subjected to HAE/HACE because of the high risk of procedure-related mortality.

  5. Accelerated large volume irradiation with dynamic Jaw/Dynamic Couch Helical Tomotherapy

    PubMed Central

    2012-01-01

    Background Helical Tomotherapy (HT) has unique capacities for the radiotherapy of large and complicated target volumes. Next generation Dynamic Jaw/Dynamic Couch HT delivery promises faster treatments and reduced exposure of organs at risk due to a reduced dose penumbra. Methods Three challenging clinical situations were chosen for comparison between Regular HT delivery with a field width of 2.5 cm (Reg 2.5) and 5.0 cm (Reg 5.0) and DJDC delivery with a maximum field width of 5.0 cm (DJDC 5.0): Hemithoracic Irradiation, Whole Abdominal Irradiation (WAI) and Total Marrow Irradiation (TMI). For each setting, five CT data sets were chosen, and target coverage, conformity, integral dose, dose exposure of organs at risk (OAR) and treatment time were calculated. Results Both Reg 5.0 and DJDC 5.0 achieved a substantial reduction in treatment time while maintaining similar dose coverage. Treatment time could be reduced from 10:57 min to 3:42 min / 5:10 min (Reg 5.0 / DJDC 5.0) for Hemithoracic Irradiation, from 18:03 min to 8:02 min / 8:03 min for WAI and to 18:25 min / 18:03 min for TMI. In Hemithoracic Irradiation, OAR exposure was identical in all modalities. For WAI, Reg 2.5 resulted in lower exposure of liver and bone. DJDC plans showed a small but significant increase of ∼ 1 Gy to the kidneys, the parotid glans and the thyroid gland. While Reg 5.0 and DJDC were identical in terms of OAR exposure, integral dose was substantially lower with DJDC, caused by a smaller dose penumbra. Conclusions Although not clinically available yet, next generation DJDC HT technique is efficient in improving the treatment time while maintaining comparable plan quality. PMID:23146914

  6. Large-volume leukapheresis for peripheral blood stem cell collection in patients with hematologic malignancies.

    PubMed

    Malachowski, M E; Comenzo, R L; Hillyer, C D; Tiegerman, K O; Berkman, E M

    1992-10-01

    Large-volume leukapheresis (LVL, 15-35 L) was performed in two groups of patients (n = 10) with hematologic malignancies to obtain peripheral blood stem cells for bone marrow rescue following high-dose chemotherapy. The target cell count was 7 x 10(8) mononuclear cells (MNCs = lymphocytes and monocytes) per kg of body weight. Group A patients (n = 4) were studied on Day 1 of LVL, and components were collected from them as four sequential samples. Total MNCs collected averaged 1.29 x 10(10), total colony-forming-units granulocyte-macrophage (CFU-GM) averaged 12.1 x 10(6), and a 1.8-fold mobilization of CFU-GM was observed (p < 0.05, Sample 1 vs. Sample 4). Group B patients (n = 6) were studied throughout the three consecutive planned days of 5-hour LVL. An average of three LVL procedures per patient was performed (range, 1.25-4), and an average of 27 L (range, 24-33) of blood per LVL was processed. The blood:ACD-A ratio was 24:1 with 3000 units of heparin per 500 mL of ACD-A; heparin was also added to the collection bags. The component had an average hematocrit (Hct) of 0.02 and MNC content of 93 percent. The patients' pre-LVL and post-LVL average Hct varied significantly (before Day 1, 0.36 +/- 0.08; after Day 3, 0.28 +/- 0.06; p < 0.05). Platelet counts also decreased, with post-Day 3 counts averaging 19 percent of the average pre-Day 1 counts (p < 0.05). A decrease in the average MNC count after LVL was significant on Day 1 only (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  7. A pomegranate-inspired nanoscale design for large-volume-change lithium battery anodes.

    PubMed

    Liu, Nian; Lu, Zhenda; Zhao, Jie; McDowell, Matthew T; Lee, Hyun-Wook; Zhao, Wenting; Cui, Yi

    2014-03-01

    Silicon is an attractive material for anodes in energy storage devices, because it has ten times the theoretical capacity of its state-of-the-art carbonaceous counterpart. Silicon anodes can be used both in traditional lithium-ion batteries and in more recent Li-O2 and Li-S batteries as a replacement for the dendrite-forming lithium metal anodes. The main challenges associated with silicon anodes are structural degradation and instability of the solid-electrolyte interphase caused by the large volume change (∼300%) during cycling, the occurrence of side reactions with the electrolyte, and the low volumetric capacity when the material size is reduced to a nanometre scale. Here, we propose a hierarchical structured silicon anode that tackles all three of these problems. Our design is inspired by the structure of a pomegranate, where single silicon nanoparticles are encapsulated by a conductive carbon layer that leaves enough room for expansion and contraction following lithiation and delithiation. An ensemble of these hybrid nanoparticles is then encapsulated by a thicker carbon layer in micrometre-size pouches to act as an electrolyte barrier. As a result of this hierarchical arrangement, the solid-electrolyte interphase remains stable and spatially confined, resulting in superior cyclability (97% capacity retention after 1,000 cycles). In addition, the microstructures lower the electrode-electrolyte contact area, resulting in high Coulombic efficiency (99.87%) and volumetric capacity (1,270 mAh cm(-3)), and the cycling remains stable even when the areal capacity is increased to the level of commercial lithium-ion batteries (3.7 mAh cm(-2)).

  8. High Pressure Research in the Large-Volume Press at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Shen, G.

    2013-05-01

    We present an overview of current status of high-pressure research using large-volume presses (LVP) at both GSECARS (Sector 13) and HPCAT (Sector 16) at the third-generation synchrotron facility of the Advanced Photon Source (APS), Argonne National Laboratory. These combined facilities provide a wide range of research capabilities for the high pressure community. The 230 ton Paris-Edinburgh device (jointly developed by HPCAT and GSECARS, with partial support from COMPRES) at the bending magnet (BM) beamline 16-BM-B has been used primarily for studies on liquids and glasses. We use the multi-angle energy-dispersive diffraction technique to probe structures of non-crystalline materials, and ultrasonic and falling sphere techniques to measure elasticity and viscosity of these materials. These capabilities allow us to examine the close link between structure and physical properties of non-crystalline metarials. The 1000 ton system at the insertion device (ID) beamline 13-ID-D is used extensively for acoustic velocity measurement for solids and melts. The newly developed DDIA-30 module, when used in a double-stage apparatus with sintered diamond anvils, can generate pressures in excess of 40 GPa routinely. DDIA-30 can also be used as a deformation device for larger samples or higher pressure experiments. The 250 ton system at beamline 13-BM-D as just been upgraded and can accommodate a variety of LVP techniques. Among them the D-DIA and the high-pressure x-ray tomography microscope (HPXTM) are at high demand. The D-DIA has been used for deformation at mantle conditions in both ductile and brittle regime, with acoustic emission detection. The HPXTM has been used to study volumetric properties of glasses and melts as well as 3D microstructure imaging under pressure. Latest scientific results will be highlighted.

  9. An energy-optimized collimator design for a CZT-based SPECT camera

    PubMed Central

    Weng, Fenghua; Bagchi, Srijeeta; Zan, Yunlong; Huang, Qiu; Seo, Youngho

    2015-01-01

    In single photon emission computed tomography, it is a challenging task to maintain reasonable performance using only one specific collimator for radio-tracers over a broad spectrum of diagnostic photon energies, since photon scatter and penetration in a collimator differ with the photon energy. Frequent collimator exchanges are inevitable in daily clinical SPECT imaging, which hinders throughput while subjecting the camera to operational errors and damage. Our objective is to design a collimator, which independent of the photon energy performs reasonably well for commonly used radiotracers with low- to medium-energy levels of gamma emissions. Using the Geant4 simulation toolkit, we simulated and evaluated a parallel-hole collimator mounted to a CZT detector. With the pixel-geometry-matching collimation, the pitch of the collimator hole was fixed to match the pixel size of the CZT detector throughout this work. Four variables, hole shape, hole length, hole radius/width and the source-to-collimator distance were carefully studied. Scatter and penetration of the collimator, sensitivity and spatial resolution of the system were assessed for four radionuclides including 57Co, 99mTc, 123I and 111In, with respect to the aforementioned four variables. An optimal collimator was then decided upon such that it maximized the total relative sensitivity (TRS) for the four considered radionuclides while other performance parameters, such as scatter, penetration and spatial resolution, were benchmarked to prevalent commercial scanners and collimators. Digital phantom studies were also performed to validate the system with the optimal square-hole collimator (23 mm hole length, 1.28 mm hole width, 0.32 mm septal thickness) in terms of contrast, contrast-to-noise ratio and recovery ratio. This study demonstrates promise of our proposed energy-optimized collimator to be used in a CZT-based gamma camera, with comparable or even better imaging performance versus commercial collimators

  10. An energy-optimized collimator design for a CZT-based SPECT camera

    NASA Astrophysics Data System (ADS)

    Weng, Fenghua; Bagchi, Srijeeta; Zan, Yunlong; Huang, Qiu; Seo, Youngho

    2016-01-01

    In single photon emission computed tomography, it is a challenging task to maintain reasonable performance using only one specific collimator for radiotracers over a broad spectrum of diagnostic photon energies, since photon scatter and penetration in a collimator differ with the photon energy. Frequent collimator exchanges are inevitable in daily clinical SPECT imaging, which hinders throughput while subjecting the camera to operational errors and damage. Our objective is to design a collimator, which is independent of the photon energy, performs reasonably well for commonly used radiotracers with low- to medium-energy levels of gamma emissions. Using the Geant4 simulation toolkit, we simulated and evaluated a parallel-hole collimator mounted to a CZT detector. With the pixel-geometry-matching collimation, the pitch of the collimator hole was fixed to match the pixel size of the CZT detector throughout this work. Four variables, hole shape, hole length, hole radius/width and the source-to-collimator distance were carefully studied. Scatter and penetration of the collimator, sensitivity and spatial resolution of the system were assessed for four radionuclides including 57Co, 99mTc, 123I and 111In, with respect to the aforementioned four variables. An optimal collimator was then decided upon such that it maximized the total relative sensitivity (TRS) for the four considered radionuclides while other performance parameters, such as scatter, penetration and spatial resolution, were benchmarked to prevalent commercial scanners and collimators. Digital phantom studies were also performed to validate the system with the optimal square-hole collimator (23 mm hole length, 1.28 mm hole width, and 0.32 mm septal thickness) in terms of contrast, contrast-to-noise ratio and recovery ratio. This study demonstrates promise of our proposed energy-optimized collimator to be used in a CZT-based gamma camera, with comparable or even better imaging performance versus commercial

  11. ProtoEXIST: advanced prototype CZT coded aperture telescopes for EXIST

    NASA Astrophysics Data System (ADS)

    Allen, Branden; Hong, Jaesub; Grindlay, Josh; Barthelmy, Scott D.; Baker, Robert G.; Gehrels, Neil A.; Garson, Trey; Krawczynski, Henric S.; Cook, Walter R.; Harrison, Fiona A.; Apple, Jeffrey A.; Ramsey, Brian D.

    2010-07-01

    ProtoEXIST1 is a pathfinder for the EXIST-HET, a coded aperture hard X-ray telescope with a 4.5 m2 CZT detector plane a 90x70 degree field of view to be flown as the primary instrument on the EXIST mission and is intended to monitor the full sky every 3 h in an effort to locate GRBs and other high energy transients. ProtoEXIST1 consists of a 256 cm2 tiled CZT detector plane containing 4096 pixels composed of an 8x8 array of individual 1.95 cm x 1.95 cm x 0.5 cm CZT detector modules each with a 8 x 8 pixilated anode configured as a coded aperture telescope with a fully coded 10° x 10° field of view employing passive side shielding and an active CsI anti-coincidence rear shield, recently completed its maiden flight out of Ft. Sumner, NM on the 9th of October 2009. During the duration of its 6 hour flight on-board calibration of the detector plane was carried out utilizing a single tagged 198.8 nCi Am-241 source along with the simultaneous measurement of the background spectrum and an observation of Cygnus X-1. Here we recount the events of the flight and report on the detector performance in a near space environment. We also briefly discuss ProtoEXIST2: the next stage of detector development which employs the NuSTAR ASIC enabling finer (32×32) anode pixilation. When completed ProtoEXIST2 will consist of a 256 cm2 tiled array and be flown simultaneously with the ProtoEXIST1 telescope.

  12. 3D porous sol-gel matrix incorporated microdevice for effective large volume cell sample pretreatment.

    PubMed

    Lee, Chan Joo; Jung, Jae Hwan; Seo, Tae Seok

    2012-06-05

    In this study, we demonstrated an effective sample pretreatment microdevice that could perform the capture, purification, and release of pathogenic bacteria with a large-volume sample and at a high speed and high-capture yield. We integrated a sol-gel matrix into the microdevice which forms three-dimensional (3D) micropores for the cell solution to pass through and provides a large surface area for the immobilization of antibodies to capture the target Staphylococcus aureus (S. aureus) cells. The antibody was linked to the surface of the sol-gel via a photocleavable linker, allowing the cell-captured antibody moiety to be released by UV irradiation. In addition to the optimization of the antibody immobilization and UV cleavage processes, the cell-capture efficiency was maximized by controlling the sample flow rate with a pumping scheme (3 steps, 5 steps: 3 steps with one flutter step, 7 steps: 3 steps with two flutter steps) and the pumping time (100, 200, and 300 ms). A quantitative capture analysis was performed by targeting a specific gene site of protein A of S. aureus in real-time PCR (RT-PCR). While the 3-step process with an actuation time of 100 ms showed the fastest flow rate (1 mL sample processing time in 10 min), the pumping scheme with the 7-step process and the 300 ms actuation time revealed the highest cell-capture efficiency. A limit of detection study with the 7-step and the 300 ms pumping scheme demonstrated that 100 cells per 100 μL were detected with a 70% yield, and even a single cell could be analyzed via on-chip sample preparation. Thus, our novel sol-gel based microdevice was proven more cost-effective, simple, and efficient in terms of its sample pretreatment ability compared to the use of a conventional 2D flat microdevice. This proposed sample pretreatment device can be further incorporated to an analytical functional unit to realize a micrototal analysis system (μTAS) with sample-in-answer-out capability in the fields of biomedical

  13. Toroidal transducer with two large focal zones for increasing the coagulated volume

    NASA Astrophysics Data System (ADS)

    Vincenot, J.; Melodelima, D.; Kocot, A.; Chavrier, F.; Chapelon, J. Y.

    2012-11-01

    Toroidal HIFU transducers have been shown to generate large conical ablations (7 cm3 in 40 seconds). The focal zone is composed of a first ring-shaped focal zone and an overlap of ultrasound beams behind this first focus. A HIFU device has been developed on this principle to treat liver metastases during an open procedure. Although these large lesions contribute to reduce treatment time, it is still needed to juxtapose 4 to 9 single HIFU lesions to treat liver metastasis (2 cm in diameter) with safety margins. In this work, a different toroidal geometry was used. With this transducer, the overlap area is located between the probe and the focal ring. The objective was to use this transducer with electronic focusing in order to create a spherical shape lesion with sufficient volume for the destruction of a metastasis of 2 cm in diameter without any mechanical displacement. The operating frequency of the toroidal transducer was 2.5 MHz. The radius of curvature was 70 mm with a diameter of 67 mm. The focal ring had a radius of 15 mm. The overlap zone extent between 35 to 55 mm from the emitting surface. An ultrasound-imaging probe (working at 7.5 MHz) was placed in a central circular opening of 26 mm in the HIFU transducer and was aligned with the focal plane. The transducer was divided into 32 rings of 78 mm2. Using a 32 channels amplifier with a phase resolution of 1.4 degrees, it was possible to change the diameter (0 to 15 mm) and depth (45 to 85 mm) of the focus circle to maximize dimensions of the lesion. Tests were conducted in vitro, in bovine liver samples. This toroidal geometry and the use of electronic beam steering allow the creation of roughly spherical lesions (diameter of 47 mm, depth of 35 mm). This treatment was obtained in 6 minutes and 10 seconds without any mechanical displacement of the transducer. The lesions obtained were homogeneous and no untreated area was observed. In conclusion, these results indicate that the treatment of a liver

  14. ANALYSIS OF LOW-LEVEL PESTICIDES FROM HIGH-ELEVATION LAKE WATERS BY LARGE VOLUME INJECTION GCMS

    EPA Science Inventory

    This paper describes the method development for the determination of ultra-low level pesticides from high-elevation lake waters by large-volume injection programmable temperature vaporizer (LVI-PTV) GC/MS. This analytical method is developed as a subtask of a larger study, backgr...

  15. Effect of filtration rates on hollow fiber ultrafilter concentration of viruses and protozoans from large volumes of water

    EPA Science Inventory

    Aims: To describe the ability of tangential flow hollow-fiber ultrafiltration to recover viruses from large volumes of water when run either at high filtration rates or lower filtration rates and recover Cryptosporidium parvum at high filtration rates. Methods and Results: Wate...

  16. 21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert...

  17. 21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert...

  18. 21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert...

  19. 21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert...

  20. 21 CFR 201.323 - Aluminum in large and small volume parenterals used in total parenteral nutrition.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... used in total parenteral nutrition. 201.323 Section 201.323 Food and Drugs FOOD AND DRUG ADMINISTRATION... parenteral nutrition. (a) The aluminum content of large volume parenteral (LVP) drug products used in total parenteral nutrition (TPN) therapy must not exceed 25 micrograms per liter (µg/L). (b) The package insert...

  1. High precision, medium flux rate CZT spectroscopy for coherent scatter imaging

    NASA Astrophysics Data System (ADS)

    Greenberg, Joel A.; Hassan, Mehadi; Brady, David J.; Iniewski, Kris

    2016-05-01

    CZT detectors are primary candidates for many next-generation X-ray imaging systems. These detectors are typically operated in either a high precision, low flux spectroscopy mode or a low precision, high flux photon counting mode. We demonstrate a new detector configuration that enables operation in a high precision, medium flux spectroscopy mode, which opens the potential for a variety of new applications in medical imaging, non-destructive testing and baggage scanning. In particular, we describe the requirements of a coded aperture coherent scattering X-ray system that can perform fast imaging with accurate material discrimination.

  2. CZT strip detectors for imaging and spectroscopy: collimated beam and ASIC readout experiments.

    NASA Astrophysics Data System (ADS)

    Kurczynski, P.; Krizmanic, J. F.; Stahle, C. M.; Parsons, A.; Palmer, D. M.; Bartlett, L. M.; Barthelmy, S. D.; Birsa, F.; Gehrels, N.; Odom, J.; Hanchak, C.; Shu, P.; Teegarden, B. J.; Tueller, J.; Barbier, L. M.

    The authors report the status of ongoing investigations into Cadmium Zinc Telluride (CZT) strip detectors for application in hard X-ray astronomy. They have instrumented a nine strip by nine strip region of a two sided strip detector. In order to measure the position resolution of the detectors, they have implemented a collimated beam that concentrates radiation to a spot size less than the strip width of the detector. The detectors exhibited excellent strip uniformity in terms of photon count rate and spectroscopic information.

  3. PBPC collection techniques: standard versus large volume leukapheresis (LVL) in donors and in patients.

    PubMed

    Gasová, Zdenka; Marinov, Iuri; Vodvárková, Sárka; Böhmová, Martina; Bhuyian-Ludvíková, Zdenka

    2005-04-01

    Transplantations of autologous and allogeneic peripheral blood progenitor cells (PBPC) are able to assure a complete hematopoietic and immunologic reconstitution in patients. PBPC are collected by leukapheresis technique after prior mobilization therapy, but procedures and results remain still highly variable and are poorly characterized. An optimum regimen for PBPC collections has not yet been recommended, but 2-3 total blood volumes (TBV) of the donor or patient are regarded as a standard. Another promising technique is large volume leukapheresis (LVL) with processing of 3-6 TBV of donor or patient. The aim of this paper is to find the most efficient and safe collection technique for an individual donor or patient and, consequently minimize the number of procedures required. Finding the optimal collection procedure would be helpful while considering which method would be preferred in an individual donor or patient with respect to the result of mobilization, health state and required yield of CD 34+ cells for transplantation. We evaluated the results in a total of 134 standard and LVL procedures, which were performed in 21 well mobilized donors (Group I), in 65 well mobilized patients (Group II), and in 14 weakly mobilized patients (Group III) with hemato-oncological diseases. A precollection concentration of CD 34+ cells in peripheral blood higher than 20 x 10(3)/mL was considered to be the criterion for efficient mobilization. Such levels of concentration indicating the start of PBPC collections could be easily reached in Group I of donors and Group II of well mobilized patients. Heavily pretreated patients at advanced stages of disease (Group III) did not respond to mobilization sufficiently and had a concentration of CD 34+ cells lower than 20x10(3)/mL. LVL technique made it possible to obtain higher numbers of CD 34+ cells than in the standard collection in well mobilized donors (Group I), well mobilized patients (Group II), and even in weakly mobilized

  4. Development of deployable structures for large space platform systems. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Cox, R. L.; Nelson, R. A.

    1983-01-01

    Candidate deployable linear platform system concepts suitable for development to technology readiness by 1986 are reviewed. The systems concepts were based on trades of alternate deployable/retractable structure concepts, integration of utilities, and interface approaches for docking and assembly of payloads and subsystems. The deployable volume studies involved generation of concepts for deployable volumes which could be used as unpressurized or pressurized hangars, habitats and interconnecting tunnels. Concept generation emphasized using flexible materials and deployable truss structure technology.

  5. Associations between IQ, total and regional brain volumes, and demography in a large normative sample of healthy children and adolescents.

    PubMed

    Lange, Nicholas; Froimowitz, Michael P; Bigler, Erin D; Lainhart, Janet E

    2010-01-01

    In the course of efforts to establish quantitative norms for healthy brain development by magnetic resonance imaging (MRI) (Brain Development Cooperative Group, 2006), previously unreported associations of parental education and temporal and frontal lobe volumes with full scale IQ and its verbal and performance subscales were discovered. Our findings were derived from the largest, most representative MRI sample to date of healthy children and adolescents, ages 4 years 10 months to 18 years 4 months. We first find that parental education has a strong association with IQ in children that is not mediated by total or regional brain volumes. Second, we find that our observed correlations between temporal gray matter, temporal white matter and frontal white matter volumes with full scale IQ, between 0.14 to 0.27 in children and adolescents, are due in large part to their correlations with performance IQ and not verbal IQ. The volumes of other lobar gray and white matter, subcortical gray matter (thalamus, caudate nucleus, putamen, and globus pallidus), cerebellum, and brainstem do not contribute significantly to IQ variation. Third, we find that head circumference is an insufficient index of cerebral volume in typically developing older children and adolescents. The relations between total and regional brain volumes and IQ can best be discerned when additional variables known to be associated with IQ, especially parental education and other demographic measures, are considered concurrently.

  6. Associations Between IQ, Total and Regional Brain Volumes and Demography in a Large Normative Sample of Healthy Children and Adolescents

    PubMed Central

    Lange, Nicholas; Froimowitz, Michael P.; Bigler, Erin D.; Lainhart, Janet E.

    2010-01-01

    In the course of efforts to establish quantitative MRI-based norms for healthy brain development (Brain Development Cooperative Group, 2006), previously unreported associations of parental education and temporal and frontal lobe volumes with full scale IQ and its verbal and performance subscales were discovered. Our findings were derived from the largest, most representative MRI sample to date of healthy children and adolescents, ages 4 years 10 months to 18 years 4 months. We first find that parental education has a strong association with IQ in children that is not mediated by total or regional brain volumes. Second, we find that our observed associations between temporal gray matter, temporal white matter and frontal white matter volumes with full scale IQ, between 0.14 to 0.27 in children and adolescents, are due in large part to their correlations with performance IQ and not verbal IQ. The volumes of other lobar gray and white matter, subcortical gray matter (thalamus, caudate nucleus, putamen and globus pallidus), cerebellum and brainstem do not contribute significantly to IQ variation. Third, we find that head circumference is an insufficient index of cerebral volume in typically developing older children and adolescents. The relations between total and regional brain volumes and IQ can best be discerned when additional variables known to be associated with IQ, especially parental education and other demographic measures, are considered concurrently. PMID:20446134

  7. Electrochemical studies on the CZT precursor deposition for CZTS solar cell application

    NASA Astrophysics Data System (ADS)

    Jin, Hyunsoo; Park, Chansu; Park, Yoosei; Kim, Yangdo; Park, Sungkyun; Choi, Jongchan; Lee, Jae-Ho

    2016-11-01

    Cu-Zn-Sn-(Se,S)(CZTS) is one of the most promising thin-film solar cells. The electrochemical methods to fabricate CZT deposits from one bath were investigated. Citrate was used to form a complex with each metallic compound. The proper potential and pH were determined from cyclic voltammetry and stability diagrams, respectively. The selected range of pH was from 4.7 to 6.2, and that of the voltage was from -0.85 V to -1.15 V (vs. Ag/AgCl). The theoretical value of the Cu/(Zn+Sn) ratio should be between 0.7 and 1.0 to shows proper photovoltaic effect. The working condition to produce such a ratio were -0.85 V at pH 4.7 and -1.15 V at pH 5.7 based on an energy dispersive spectrometer analysis of the deposits. Deposits at -1.15 V and pH 5.7 were denser than those at -0.85 V and pH 4.7. Finally, -1.15 V and pH 5.7 was selected optimum condition for the electrodeposition of the CZT precursor.

  8. Multipixel characterization of imaging CZT detectors for hard x-ray imaging and spectroscopy

    NASA Astrophysics Data System (ADS)

    Vadawale, Santosh V.; Hong, Jae Sub; Grindlay, Jonathan E.; Williams, Peter; Zhang, Minhua; Bellm, Eric C.; Narita, Tomohiko; Craig, William W.; Parker, Bradford H.; Stahle, Carl M.; Yan, Feng

    2004-10-01

    We report our in-depth study of Cd-Zn-Te (CZT) crystals to determine an optimum pixel and guard band configuration for Hard X-ray imaging and spectroscopy. We tested 20x20x5mm crystals with 8x8 pixels on a 2.46mm pitch. We have studied different types of cathode / anode contacts and different pixel pad sizes. We present the measurements of leakage current as well as spectral response for each pixel. Our I-V measurement setup is custom designed to allow automated measurements of the I-V curves sequentially for all 64 pixels, whereas the radiation properties measurement setup allows for interchangeable crystals with the same XAIM3.2 ASIC readout from IDEAS. We have tested multiple crystals of each type, and each crystal in different positions to measure the variation between individual crystals and variation among the ASIC channels. We also compare the same crystals with and without a grounded guard band deposited on the crystal side walls vs. a floating guard band and compare results to simulations. This study was carried out to find the optimum CZT crystal configuration for prototype detectors for the proposed Black-Hole Finder mission, EXIST.

  9. Optical property analysis of high-resistivity CZT:In single crystals before and after annealing

    NASA Astrophysics Data System (ADS)

    Yu, Pengfei; Jie, Wanqi

    2014-05-01

    In-doped CdZnTe:In (CZT:In) single crystals with high resistivity were annealed by an effective method containing Cd/Zn atmosphere annealing and Te atmosphere annealing. They were mainly measured by IR transmittance and Photoluminescence (PL) spectra. The results indicated Te inclusions were eliminated completely after annealing. Both of the resistivity and IR transmittance decreased notably after Cd/Zn atmosphere annealing, and then increased tremendously after Te atmosphere annealing. For PL measurements, (A0, X) disappeared, the intensity of (D0, X) peak increased, and FWHM was obviously reduced after annealing. These indicated the crystal quality was enhanced. The donor-acceptor pair peak decreased in annealed CZT:In crystal, which might be due to the dissociation of [VCd-InCd] complex and the remove of the impurities. Moreover, Dcomplex peak containing two peaks was caused by Cd vacancy-related (D1) and dislocation-related defects (D2) in as-grown crystal. However, after annealing, the intensities of D1 and D2 peaks decreased because of the compensation of Cd vacancies and the elimination of Te inclusions, respectively.

  10. Detection of triazole deicing additives in soil samples from airports with low, mid, and large volume aircraft deicing activities.

    PubMed

    McNeill, K S; Cancilla, D A

    2009-03-01

    Soil samples from three USA airports representing low, mid, and large volume users of aircraft deicing fluids (ADAFs) were analyzed by LC/MS/MS for the presence of triazoles, a class of corrosion inhibitors historically used in ADAFs. Triazoles, specifically the 4-methyl-1H-benzotriazole and the 5-methyl-1H-benzotriazole, were detected in a majority of samples and ranged from 2.35 to 424.19 microg/kg. Previous studies have focused primarily on ground and surface water impacts of larger volume ADAF users. The detection of triazoles in soils at low volume ADAF use airports suggests that deicing activities may have a broader environmental impact than previously considered.

  11. Systems and methods for the detection of low-level harmful substances in a large volume of fluid

    SciTech Connect

    Carpenter, Michael V.; Roybal, Lyle G.; Lindquist, Alan; Gallardo, Vincente

    2016-03-15

    A method and device for the detection of low-level harmful substances in a large volume of fluid comprising using a concentrator system to produce a retentate and analyzing the retentate for the presence of at least one harmful substance. The concentrator system performs a method comprising pumping at least 10 liters of fluid from a sample source through a filter. While pumping, the concentrator system diverts retentate from the filter into a container. The concentrator system also recirculates at least part of the retentate in the container again through the filter. The concentrator system controls the speed of the pump with a control system thereby maintaining a fluid pressure less than 25 psi during the pumping of the fluid; monitors the quantity of retentate within the container with a control system, and maintains a reduced volume level of retentate and a target volume of retentate.

  12. Modification of solid state CdZnTe (CZT) radiation detectors with high sensitivity or high resolution operation

    DOEpatents

    Washington, II, Aaron L; Duff, Martine C; Teague, Lucile C; Burger, Arnold; Groza, Michael

    2014-11-11

    An apparatus and process is provided to illustrate the manipulation of the internal electric field of CZT using multiple wavelength light illumination on the crystal surface at RT. The control of the internal electric field is shown through the polarization in the IR transmission image under illumination as a result of the Pockels effect.

  13. Long-term stability of underground operated CZT detectors based on the analysis of intrinsic 113Cd β--decay

    NASA Astrophysics Data System (ADS)

    Ebert, J.; Gößling, C.; Gehre, D.; Hagner, C.; Heidrich, N.; Klingenberg, R.; Kröninger, K.; Nitsch, C.; Oldorf, C.; Quante, T.; Rajek, S.; Rebber, H.; Rohatsch, K.; Tebrügge, J.; Temminghoff, R.; Theinert, R.; Timm, J.; Wonsak, B.; Zatschler, S.; Zuber, K.

    2016-06-01

    The COBRA collaboration operates a demonstrator setup at the underground facility Laboratori Nazionali del Gran Sasso (LNGS, located in Italy) to prove the technological capabilities of this concept for the search for neutrinoless double beta-decay. The setup consists of 64 (1×1×1) cm3 Cadmium-Zinc-Telluride (CZT) detectors in Coplanar-Grid (CPG) configuration. One purpose of this demonstrator is to test if reliable long-term operation of CZT-CPG detectors in such a setup is possible. The demonstrator has been operated under ultra low-background conditions for more than three years and collected data corresponding to a total exposure of 218 kg days. The presented study focuses on the long-term stability of CZT detectors by analyzing the intrinsic, fourfold forbidden non-unique 113Cd single beta-decay. It can be shown that CZT detectors can be operated stably for long periods of time and that the 113Cd single beta-decay can be used as an internal monitor of the detector performance during the runtime of the experiment.

  14. Development of deployable structures for large space platforms. Volume 2: Design development

    NASA Technical Reports Server (NTRS)

    Greenberg, H. S.

    1983-01-01

    Design evolution, test article design, test article mass properties, and structural analysis of deployable platform systems are discussed. Orbit transfer vehicle (OTV) hangar development, OTV hangar concept selection, and manned module development are discussed. Deployable platform systems requirements, material data base, technology development needs, concept selection and deployable volume enclosures are also discussed.

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

    EPA Science Inventory

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

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

  16. Fabrics, Facies And Flow Through A Large-Volume Ignimbrite: Pampa De Oxaya, Chile.

    NASA Astrophysics Data System (ADS)

    Platzman, Ellen; Cooper, Frances

    2016-04-01

    Large volume pyroclastic currents form during some of the most destructive volcanic eruptions on the planet, yet because they are underrepresented in the geological record they remain poorly understood. The Miocene Oxaya ignimbrites, exposed along the western Andean slopes in northern Chile, form one of the largest ignimbrite provinces on earth. We use anisotropy of magnetic susceptibility (AMS) in conjunction with rock magnetic measurements to investigate flow behavior and depositional processes in one of the largest members of the Oxaya succession, the Cardones ignimbrite. Despite its prominence the location of the source caldera remains unknown and fundamental processes remain poorly constrained. During 2012 nearly 8km (7,773m) of core was recovered from the early Miocene ignimbrites in 11 holes at elevations ranging from 2336m to 3805m along the Andean escarpment east of Arica, Chile. The drill cores are remarkable in that they penetrate through the entirety of the ignimbrite sequence and into the basement below. Samples for this study were collected from a > 1 km long core drilled at an altitude 3692m. The core sampled 981 m of Cardones ignimbrite and 15 m of underlying sediments and volcaniclastics before penetrating 148 m of basement. Detailed measurements of the variation in bulk magnetic properties including natural remanent magnetization (NRM), susceptibility, ARM, and IRM, were used to monitor changes in concentration, composition and grainsize of the magnetic components though the ignimbrite. AMS in conjunction with detailed rock magnetic measurements were used to constrain flow processes. The data reveal a well-defined flow direction and systematic variations in flow processes with depth. Low field bulk magnetic susceptibility averages 3.2x10-3 SI. Rock magnetic studies and petrographic examination indicate that magnetite is likely to be the dominant magnetic phase although paramagnetic mineral phases also contribute to the magnetic fabric. The degree

  17. Teaching Large Classes: Tools and Strategies. Survival Skills for Scholars, Volume 19.

    ERIC Educational Resources Information Center

    Carbone, Elisa

    This book deals with the challenges of teaching large classes at institutions of higher learning, and addresses such issues as how instruction can be personalized and made more interactive with large numbers of students. The material for the book arose out of a "large classes project" at the University of Maryland, where the subject was…

  18. Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks.

    PubMed

    Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

    2016-11-01

    Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors' best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well.

  19. Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks

    PubMed Central

    Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

    2016-01-01

    Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well. PMID:27809285

  20. Genetic influences on schizophrenia and subcortical brain volumes: large-scale proof of concept.

    PubMed

    Franke, Barbara; Stein, Jason L; Ripke, Stephan; Anttila, Verneri; Hibar, Derrek P; van Hulzen, Kimm J E; Arias-Vasquez, Alejandro; Smoller, Jordan W; Nichols, Thomas E; Neale, Michael C; McIntosh, Andrew M; Lee, Phil; McMahon, Francis J; Meyer-Lindenberg, Andreas; Mattheisen, Manuel; Andreassen, Ole A; Gruber, Oliver; Sachdev, Perminder S; Roiz-Santiañez, Roberto; Saykin, Andrew J; Ehrlich, Stefan; Mather, Karen A; Turner, Jessica A; Schwarz, Emanuel; Thalamuthu, Anbupalam; Yao, Yin; Ho, Yvonne Y W; Martin, Nicholas G; Wright, Margaret J; O'Donovan, Michael C; Thompson, Paul M; Neale, Benjamin M; Medland, Sarah E; Sullivan, Patrick F

    2016-03-01

    Schizophrenia is a devastating psychiatric illness with high heritability. Brain structure and function differ, on average, between people with schizophrenia and healthy individuals. As common genetic associations are emerging for both schizophrenia and brain imaging phenotypes, we can now use genome-wide data to investigate genetic overlap. Here we integrated results from common variant studies of schizophrenia (33,636 cases, 43,008 controls) and volumes of several (mainly subcortical) brain structures (11,840 subjects). We did not find evidence of genetic overlap between schizophrenia risk and subcortical volume measures either at the level of common variant genetic architecture or for single genetic markers. These results provide a proof of concept (albeit based on a limited set of structural brain measures) and define a roadmap for future studies investigating the genetic covariance between structural or functional brain phenotypes and risk for psychiatric disorders.

  1. The Life of William Thomson, Baron Kelvin of Largs 2 Volume Set

    NASA Astrophysics Data System (ADS)

    Thompson, Silvanus Phillips

    2011-05-01

    Volume 1: Preface; 1. Childhood, and upbringing at Glasgow; 2. Cambridge; 3. Post-graduate studies at Paris and Peterhouse; 4. The Glasgow Chair; 5. The young professor; 6. Thermodynamics; 7. The laboratory; 8. The Atlantic telegraph: failure; 9. Strenuous years; 10. The epoch-making treatise; 11. The Atlantic telegraph: success; 12. Labour and sorrow; 13. The geological controversy; 14. Later telegraphic work: the siphon recorder. Volume 2: 15. The 'Lalla Rookh', the British Association, and the 'Hooper'; 16. In the Seventies; 17. Navigation - the compass and the sounding machine; 18. Gyrostatics and wave motion; 19. In the Eighties; 20. The Baltimore lectures; 21. Gathering up the threads; 22. The peerage; 23. The jubilee. Retirement; 24. The great comprehensive theory; 25. Views and opinions; 26. The closing years; Appendices; Index.

  2. Gravitational search for cryptovolcanism on the Moon: Evidence for large volumes of early igneous activity

    NASA Astrophysics Data System (ADS)

    Sori, Michael M.; Zuber, Maria T.; Head, James W.; Kiefer, Walter S.

    2016-07-01

    We define lunar cryptovolcanism as volcanic deposits on the Moon hidden by overlying material. Notably, cryptovolcanism includes both cryptomaria (subsurface extrusive basaltic deposits that are obscured by overlying higher albedo basin and crater ejecta) and earlier candidate extrusives, such as the Mg-suite. Knowledge of the volume and extent of cryptovolcanism is necessary for a comprehensive understanding of lunar volcanic history, particularly in early (pre 3.8 Ga) epochs when abundant impact craters and basins obscured surface volcanic deposits by lateral emplacement of ejecta. We use Gravity Recovery and Interior Laboratory (GRAIL) gravity and Lunar Orbiter Laser Altimeter (LOLA) topography data to construct maps of the Moon's positive Bouguer and isostatic gravity anomalies, and explore the possibility that these features are due to mass excesses associated with cryptovolcanism by cross-referencing the regions with geologic data such as dark halo craters. We model the potential cryptovolcanic deposits as buried high-density rectangular prisms at depth in the upper crust, and find a volume of candidate buried cryptovolcanism between 0.4 × 106 km3 and 4.8 × 106 km3, depending on assumptions about density and crustal compensation state. These candidate deposits correspond to a surface area of between 0.50 × 106 km2 and 1.14 × 106 km2, which would increase the amount of the lunar surface containing volcanic deposits from 16.6% to between 17.9% and 19.5%. The inferred volume of cryptovolcanism is comparable to the smallest estimates of the volume of visible mare basalts and up to ∼50% of the largest estimates; the high-resolution GRAIL and LOLA observations thus would collectively indicate that early (pre 3.8 Ga) lunar volcanism is an important element of lunar thermal evolution. Alternatively, the buried material could represent the presence of intrusive Mg-suite sills or plutons.

  3. A 3D time reversal cavity for the focusing of high-intensity ultrasound pulses over a large volume

    NASA Astrophysics Data System (ADS)

    Robin, J.; Arnal, B.; Tanter, M.; Pernot, M.

    2017-02-01

    Shock wave ultrasound therapy techniques, increasingly used for non-invasive surgery, require extremely high pressure amplitudes in precise focal spots, and large high-power transducers arranged on a spherical shell are usually used to achieve that. This solution allows limited steering of the beam around the geometrical focus of the device at the cost of a large number of transducer elements, and the treatment of large and moving organs like the heart is challenging or impossible. This paper validates numerically and experimentally the possibility of using a time reversal cavity (TRC) for the same purpose. A 128-element, 1 MHz power transducer combined with different multiple scattering media in a TRC was used. We were able to focus high-power ultrasound pulses over a large volume in a controlled manner, with a limited number of transducer elements. We reached sufficiently high pressure amplitudes to erode an Ultracal® target over a 10 cm2 area.

  4. Large scale prop-fan structural design study. Volume 1: Initial concepts

    NASA Technical Reports Server (NTRS)

    Billman, L. C.; Gruska, C. J.; Ladden, R. M.; Leishman, D. K.; Turnberg, J. E.

    1988-01-01

    In recent years, considerable attention has been directed toward improving aircraft fuel consumption. Studies have shown that the inherent efficiency advantage that turboprop propulsion systems have demonstrated at lower cruise speeds may now be extended to the higher speeds of today's turbofan and turbojet-powered aircraft. To achieve this goal, new propeller designs will require features such as thin, high speed airfoils and aerodynamic sweep, features currently found only in wing designs for high speed aircraft. This is Volume 1 of a 2 volume study to establish structural concepts for such advanced propeller blades, to define their structural properties, to identify any new design, analysis, or fabrication techniques which were required, and to determine the structural tradeoffs involved with several blade shapes selected primarily on the basis of aero/acoustic design considerations. The feasibility of fabricating and testing dynamically scaled models of these blades for aeroelastic testing was also established. The preliminary design of a blade suitable for flight use in a testbed advanced turboprop was conducted and is described in Volume 2.

  5. Very Large Data Volumes Analysis of Collaborative Systems with Finite Number of States

    ERIC Educational Resources Information Center

    Ivan, Ion; Ciurea, Cristian; Pavel, Sorin

    2010-01-01

    The collaborative system with finite number of states is defined. A very large database is structured. Operations on large databases are identified. Repetitive procedures for collaborative systems operations are derived. The efficiency of such procedures is analyzed. (Contains 6 tables, 5 footnotes and 3 figures.)

  6. Systems definition study for shuttle demonstration flights of large space structures. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The development of large space structure technology is discussed, with emphasis on space fabricated structures which are automatically manufactured in space from sheet-strip materials and assembled on-orbit. Definition of a flight demonstration involving an Automated Beam Builder and the building and assembling of large structures is presented.

  7. Estimating the eruptive volume of a large pyroclastic body: the Otowi Member of the Bandelier Tuff, Valles caldera, New Mexico

    NASA Astrophysics Data System (ADS)

    Cook, Geoffrey W.; Wolff, John A.; Self, Stephen

    2016-02-01

    The 1.60 Ma caldera-forming eruption of the Otowi Member of the Bandelier Tuff produced Plinian and coignimbrite fall deposits, outflow and intracaldera ignimbrite, all of it deposited on land. We present a detailed approach to estimating and reconstructing the original volume of the eroded, partly buried large ignimbrite and distal ash-fall deposits. Dense rock equivalent (DRE) volume estimates for the eruption are 89 + 33/-10 km3 of outflow ignimbrite and 144 ± 72 km3 of intracaldera ignimbrite. Also, there was at least 65 km3 (DRE) of Plinian fall when extrapolated distally, and 107 + 40/-12 km3 of coignimbrite ash was "lost" from the outflow sheet to form an unknown proportion of the distal ash fall. The minimum total volume is 216 km3 and the maximum is 550 km3; hence, the eruption overlaps the low end of the super-eruption spectrum (VEI ˜8.0). Despite an abundance of geological data for the Otowi Member, the errors attached to these estimates do not allow us to constrain the proportions of intracaldera (IC), outflow (O), and distal ash (A) to better than a factor of three. We advocate caution in applying the IC/O/A = 1:1:1 relation of Mason et al. (2004) to scaling up mapped volumes of imperfectly preserved caldera-forming ignimbrites.

  8. Construction of Large-Volume Tissue Mimics with 3D Functional Vascular Networks

    PubMed Central

    Kang, Tae-Yun; Hong, Jung Min; Jung, Jin Woo; Kang, Hyun-Wook; Cho, Dong-Woo

    2016-01-01

    We used indirect stereolithography (SL) to form inner-layered fluidic networks in a porous scaffold by introducing a hydrogel barrier on the luminal surface, then seeded the networks separately with human umbilical vein endothelial cells and human lung fibroblasts to form a tissue mimic containing vascular networks. The artificial vascular networks provided channels for oxygen transport, thus reducing the hypoxic volume and preventing cell death. The endothelium of the vascular networks significantly retarded the occlusion of channels during whole-blood circulation. The tissue mimics have the potential to be used as an in vitro platform to examine the physiologic and pathologic phenomena through vascular architecture. PMID:27228079

  9. 3-D EM exploration of the hepatic microarchitecture – lessons learned from large-volume in situ serial sectioning

    PubMed Central

    Shami, Gerald John; Cheng, Delfine; Huynh, Minh; Vreuls, Celien; Wisse, Eddie; Braet, Filip

    2016-01-01

    To-date serial block-face scanning electron microscopy (SBF-SEM) dominates as the premier technique for generating three-dimensional (3-D) data of resin-embedded biological samples at an unprecedented depth volume. Given the infancy of the technique, limited literature is currently available regarding the applicability of SBF-SEM for the ultrastructural investigation of tissues. Herein, we provide a comprehensive and rigorous appraisal of five different SBF-SEM sample preparation protocols for the large-volume exploration of the hepatic microarchitecture at an unparalleled X, Y and Z resolution. In so doing, we qualitatively and quantitatively validate the use of a comprehensive SBF-SEM sample preparation protocol, based on the application of heavy metal fixatives, stains and mordanting agents. Employing the best-tested SBF-SEM approach, enabled us to assess large-volume morphometric data on murine parenchymal cells, sinusoids and bile canaliculi. Finally, we integrated the validated SBF-SEM protocol with a correlative light and electron microscopy (CLEM) approach. The combination of confocal scanning laser microscopy and SBF-SEM provided a novel way to picture subcellular detail. We appreciate that this multidimensional approach will aid the subsequent research of liver tissue under relevant experimental and disease conditions. PMID:27834401

  10. 3-D EM exploration of the hepatic microarchitecture - lessons learned from large-volume in situ serial sectioning.

    PubMed

    Shami, Gerald John; Cheng, Delfine; Huynh, Minh; Vreuls, Celien; Wisse, Eddie; Braet, Filip

    2016-11-11

    To-date serial block-face scanning electron microscopy (SBF-SEM) dominates as the premier technique for generating three-dimensional (3-D) data of resin-embedded biological samples at an unprecedented depth volume. Given the infancy of the technique, limited literature is currently available regarding the applicability of SBF-SEM for the ultrastructural investigation of tissues. Herein, we provide a comprehensive and rigorous appraisal of five different SBF-SEM sample preparation protocols for the large-volume exploration of the hepatic microarchitecture at an unparalleled X, Y and Z resolution. In so doing, we qualitatively and quantitatively validate the use of a comprehensive SBF-SEM sample preparation protocol, based on the application of heavy metal fixatives, stains and mordanting agents. Employing the best-tested SBF-SEM approach, enabled us to assess large-volume morphometric data on murine parenchymal cells, sinusoids and bile canaliculi. Finally, we integrated the validated SBF-SEM protocol with a correlative light and electron microscopy (CLEM) approach. The combination of confocal scanning laser microscopy and SBF-SEM provided a novel way to picture subcellular detail. We appreciate that this multidimensional approach will aid the subsequent research of liver tissue under relevant experimental and disease conditions.

  11. Effects of large volume, ice-cold intravenous fluid infusion on respiratory function in cardiac arrest survivors.

    PubMed

    Jacobshagen, Claudius; Pax, Anja; Unsöld, Bernhard W; Seidler, Tim; Schmidt-Schweda, Stephan; Hasenfuss, Gerd; Maier, Lars S

    2009-11-01

    International guidelines for cardiopulmonary resuscitation recommend mild hypothermia (32-34 degrees C) for 12-24h in comatose survivors of cardiac arrest. To induce therapeutic hypothermia a variety of external and intravascular cooling devices are available. A cheap and effective method for inducing hypothermia is the infusion of large volume, ice-cold intravenous fluid. There are concerns regarding the effects of rapid infusion of large volumes of fluid on respiratory function in cardiac arrest survivors. We have retrospectively studied the effects of high volume cold fluid infusion on respiratory function in 52 resuscitated cardiac arrest patients. The target temperature of 32-34 degrees C was achieved after 4.1+/-0.5h (cooling rate 0.48 degrees C/h). During this period 3427+/-210 mL ice-cold fluid was infused. Despite significantly reduced LV-function (EF 35.8+/-2.2%) the respiratory status of these patients did not deteriorate significantly. On intensive care unit admission the mean PaO(2) was 231.4+/-20.6 mmHg at a F(i)O(2) of 0.82+/-0.03 (PaO(2)/F(i)O(2)=290.0+/-24.1) and a PEEP level of 7.14+/-0.31 mbar. Until reaching the target temperature of large volume, ice-cold fluid is an effective and inexpensive method for inducing therapeutic hypothermia. Resuscitation from cardiac arrest is associated with a deterioration in respiratory function. The infusion of large volumes of cold fluid does not cause a statistically significant further deterioration in respiratory function. A larger, randomized and prospective study is required to assess the efficacy and safety of ice-cold fluid infusion for

  12. Prospective, randomized, sequential, crossover trial of large-volume vs. normal-volume leukapheresis procedures: effects on subpopulations of CD34(+) cells.

    PubMed

    Humpe, A; Riggert, J; Koch, S; Legler, T J; Munzel, U; Köhler, M

    2001-01-01

    Some data exist on the influence of leukapheresis volume on the number of harvested peripheral blood hematopoietic progenitor cells (HPC), but less is known about the influence on the composition of HPC. We therefore performed a prospective, randomized crossover trial to evaluate the effect of large-volume (LVL) vs. normal-volume leukapheresis (NVL) on subpopulations of CD34(+) cells in the harvest product of 15 patients with breast cancer and 8 patients with non-Hodgkin's lymphoma. Patients were randomly assigned to start either with an LVL on day 1 followed by an NVL on day 2 or vice versa. The number of HPC, the extraction efficiency defined as difference between yield in the harvest and decrease in peripheral blood, and the relative proportion as well as the absolute numbers of CD34(+) cells coexpressing CD38, CD90, HLA-DR, CD117, CD7, CD19, CD41, or CD33 were evaluated. There was no significant difference with regard to the percentages of the subsets on comparison of LVL to NVL procedures. Only the absolute median number of CD34(+)HLA-DR(-) cells was significantly (P=0.02) higher in LVL harvests compared with the corresponding NVL components, which can be explained on the basis of the higher yield and the higher extraction efficiency in LVL compared with NVL. LVL results in a higher yield of CD34(+) cells and leads to an intra-apheresis recruitment of HPC but the relative composition of the harvested CD34(+) cells is not changed significantly. In addition, the amount of early, HLA-DR(-), hematopoietic HPC seems to be increased by an LVL.

  13. Development and evaluation of a portable CZT coded aperture gamma-camera

    SciTech Connect

    Montemont, G.; Monnet, O.; Stanchina, S.; Maingault, L.; Verger, L.; Carrel, F.; Lemaire, H.; Schoepff, V.; Ferrand, G.; Lalleman, A.-S.

    2015-07-01

    We present the design and the evaluation of a CdZnTe (CZT) based gamma camera using a coded aperture mask. This camera, based on a 8 cm{sup 3} detection module, is small enough to be portable and battery-powered (4 kg weight and 4 W power dissipation). As the detector has spectral capabilities, the gamma camera allows isotope identification and colored imaging, by affecting one color channel to each identified isotope. As all data processing is done at real time, the user can directly observe the outcome of an acquisition and can immediately react to what he sees. We first present the architecture of the system, how the detector works, and its performances. After, we focus on the imaging technique used and its strengths and limitations. Finally, results concerning sensitivity, spatial resolution, field of view and multi-isotope imaging are shown and discussed. (authors)

  14. Evaluation of a Wobbling Method Applied to Correcting Defective Pixels of CZT Detectors in SPECT Imaging

    PubMed Central

    Xie, Zhaoheng; Li, Suying; Yang, Kun; Xu, Baixuan; Ren, Qiushi

    2016-01-01

    In this paper, we propose a wobbling method to correct bad pixels in cadmium zinc telluride (CZT) detectors, using information of related images. We build up an automated device that realizes the wobbling correction for small animal Single Photon Emission Computed Tomography (SPECT) imaging. The wobbling correction method is applied to various constellations of defective pixels. The corrected images are compared with the results of conventional interpolation method, and the correction effectiveness is evaluated quantitatively using the factor of peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In summary, the proposed wobbling method, equipped with the automatic mechanical system, provides a better image quality for correcting defective pixels, which could be used for all pixelated detectors for molecular imaging. PMID:27240368

  15. Large scale prop-fan structural design study. Volume 2: Preliminary design of SR-7

    NASA Technical Reports Server (NTRS)

    Billman, L. C.; Gruska, C. J.; Ladden, R. M.; Leishman, D. K.; Turnberg, J. E.

    1988-01-01

    In recent years, considerable attention has been directed toward improving aircraft fuel consumption. Studies have shown that the inherent efficiency advantage that turboprop propulsion systems have demonstrated at lower cruise speeds may now be extended to the higher speeds of today's turbofan and turbojet-powered aircraft. To achieve this goal, new propeller designs will require features such as thin, high speed airfoils and aerodynamic sweep, features currently found only in wing designs for high speed aircraft. This is Volume 2 of a 2 volume study to establish structural concepts for such advanced propeller blades, to define their structural properties, to identify any new design, analysis, or fabrication techniques which were required, and to determine the structural tradeoffs involved with several blade shapes selected primarily on the basis of aero/acoustic design considerations. The feasibility of fabricating and testing dynamically scaled models of these blades for aeroelastic testing was also established. The preliminary design of a blade suitable for flight use in a testbed advanced turboprop was conducted and is described.

  16. Nuclear waste calorimeter for very large drums with 385 litres sample volume

    SciTech Connect

    Jossens, G.; Mathonat, C.; Bachelet, F.

    2015-03-15

    Calorimetry is a very precise and well adapted tool for the classification of drums containing nuclear waste material depending on their level of activities (low, medium, high). A new calorimeter has been developed by SETARAM Instrumentation and the CEA Valduc in France. This new calorimeter is designed for drums having a volume bigger than 100 liters. It guarantees high operator safety by optimizing drum handling and air circulation for cooling, and optimized software for direct measurement of the quantity of nuclear material. The LVC1380 calorimeter makes it possible to work over the range 10 to 3000 mW, which corresponds to approximately 0.03 to 10 g of tritium or 3 to 955 g of {sup 241}Pu in a volume up to 385 liters. This calorimeter is based on the heat flow measurement using Peltier elements which surround the drum in the 3 dimensions and therefore measure all the heat coming from the radioactive stuff whatever its position inside the drum. Calorimeter's insulating layers constitute a thermal barrier designed to filter disturbances until they represent less than 0.001 Celsius degrees and to eliminate long term disturbances associated, for example, with laboratory temperature variations between day and night. A calibration device based on Joule effect has also been designed. Measurement time has been optimized but remains long compared with other methods of measurement such as gamma spectrometry but its main asset is to have a good accuracy for low level activities.

  17. Performance of three large-volume infusion pumps with the monoplace hyperbaric chamber.

    PubMed

    Bell, James; Weaver, Lindell K; Deru, Kayla

    2016-01-01

    We evaluated the Zyno Medical Z-800F, CME Body Guard 323 Color Vision, and Baxter Flo-Gard 6201 infusion pumps for monoplace chamber conditions. We adjusted pump occlusion pressure allowing infusion to 3 atmospheres absolute (atm abs). Baxter and Zyno pumps were connected to the chamber pass-through with rigid small-bore tubing. The CME infusion set was connected directly to the pass-through. We infused saline to a collection manifold inside a monoplace chamber at 1-100 mL/ hour under pressures ranging from 0.85-3.0 atm abs. We averaged results from three to five separate tests for each condition. At baseline, pumps performed within ±10% of expected (our measurement capability). However, clinical engineering verified performance within manufacturer specifications (±5% at atmospheric pressure). During a carbon monoxide hyperbaric protocol (3 atm abs/2 atm abs), measured flow with the Baxter, CME and Zyno pumps was ±5% of setting at 10 mL/hour (95%, 103%, 95%, respectively); at 1 mL/hour, average flow were 91%, 83%, 83%, respectively. During timed testing (volume recorded before decompression), pump accuracy was ±10% at 10 and 100 mL/hour. Tubing compliance compromised performance at lower flow rates, magnified by increased pressure. These pumps have potential for monoplace chamber use, although not supported by the manufacturers or FDA-cleared. At low flow rates, tubing compliance affects delivered volumes.

  18. A single-frequency ECR ion source with a large uniformly distributed resonant plasma volume

    SciTech Connect

    Alton, G.D.; Smithe, D.N.

    1995-12-01

    An innovative technique for increasing ion source intensity is described which, in principle, could lead to significant advances in ECR ion source technology for multiply charged ion beam formation. The advanced concept design uses a minimum-B magnetic mirror geometry which consists of a multi-cusp, magnetic field, to assist in confining the plasma radially, a flat central field for tuning to the ECR resonant condition, and specially tailored mirror fields in the end zones to confine the plasma in the axial direction. The magnetic field is designed to achieve an axially symmetric plasma {open_quotes}volume{close_quotes} with constant mod-B, which extends over the length of the central field region. This design, which strongly contrasts with the ECR {open_quotes}surfaces{close_quotes} characteristic of conventional ECR ion sources, results in dramatic increases in the absorption of RF power, thereby increasing the electron temperature and {open_quotes}hot{close_quotes} electron population within the ionization volume of the source.

  19. Proceedings of the Large Deployable Reflector Science and Technology Workshop. Volume 1: Executive Summary

    NASA Technical Reports Server (NTRS)

    Leidich, C. A.; Pittman, B.

    1984-01-01

    A large ambient temperature, for infrared submillimeter telescope in space was discussed. The results of the scientific and technical activities were summarized. The scientific effort consisted of reviewing the science rationale for the Large Deployable Reflector (LDR) and arriving at a concensus set of scientific requirements. The telescope requirements were then compared to the current and anticipated state of the various technologies involved, and the technological shortfalls identified.

  20. Large Deployable Reflector Science and Technology Workshop. Volume 3: Systems and Technology Assessment

    NASA Technical Reports Server (NTRS)

    Leidich, C. A. (Editor); Pittman, R. B. (Editor)

    1984-01-01

    The results of five technology panels which convened to discuss the Large Deployable Reflector (LDR) are presented. The proposed LDR is a large, ambient-temperature, far infrared/submillimeter telescope designed for space. Panel topics included optics, materials and structures, sensing and control, science instruments, and systems and missions. The telescope requirements, the estimated technology levels, and the areas in which the generic technology work has to be augmented are enumerated.

  1. The importance of preoperative hemoglobin evaluation in large volume liposuction: lessons learned from our 15-year experience.

    PubMed

    Choudry, Umar H; Hyza, Petr; Lane, Jason; Petty, Paul

    2008-09-01

    Liposuction of >5 L of total aspirate at one setting is defined as large volume liposuction (LVL). A retrospective chart review was performed on all patients who underwent LVL from January 1990 to June 2005. Sixty-two patients underwent LVL. The mean volume of total aspirate was 8 L (5.0-11.7 L). There were a total of 6 patients who had complications. These included symptomatic postoperative anemia requiring blood transfusions on postoperative day 1 (n = 5), and an expanding hematoma requiring operative evacuation without transfusion (n = 1). Two of the patients who had blood transfusions had a history of gastric bypass and all of the patients were preoperatively anemic (<11.5 mg/dL). The mean follow up was 38 months. LVL is safe when performed in healthy patients under strict guidelines. Hemoglobin levels of all potential LVL patients should be checked preoperatively, and surgery should be withheld for levels <12 g/dL.

  2. Motion detection and amelioration in a dedicated cardiac solid-state CZT SPECT device.

    PubMed

    Kennedy, John A; William Strauss, H

    2017-04-01

    A solid-state cadmium zinc tellurium (CZT) dedicated multipinhole cardiac camera which acquires all views simultaneously has been introduced for myocardial SPECT acquisition. We report a method to detect and ameliorate patient motion artifacts in myocardial perfusion imaging (MPI) studies recorded with this device. To detect motion, a myocardial phantom study was recorded, and at mid-scan, the phantom was moved stepwise along each of 6 orthogonal directions, causing MPI artifacts. Using QPS software (Cedars-Sinai) and an in-house normal database, displacements giving artifactual perfusion defects (total perfusion deficit score, TPD, >5 %) were all 1.5 cm or greater (11.2 ± 1.3 % for 1.5 cm). List mode data were reframed into 10-s steps, and the norm of the changes in center of mass among the 19 projections (32 × 32 matrix, pixel size 2.46 mm) was used as a motion index. Rejection of misregistered data gave artifact-free reconstructions (TPD = 1.0 ± 0.8 %) in phantom scans and reduced blur in a rest/stress clinical study. Blur on the patient's stress scan was consistent with increased motion compared to rest (motion index of 4.4 vs. 3.0 pixels, respectively). For CZT cameras that acquire data from multiple views simultaneously, motion during MPI can cause clinically significant artifacts. Reframing acquisitions into discrete time intervals enables the detection of motion and its amelioration, improving diagnostic accuracy.

  3. Development of a low noise readout ASIC for CZT detectors for gamma-ray spectroscopy applications

    NASA Astrophysics Data System (ADS)

    Luo, J.; Deng, Z.; Wang, G.; Li, H.; Liu, Y.

    2012-08-01

    A multi-channel readout ASIC for pixelated CZT detectors has been developed for gamma-ray spectroscopy applications. Each channel consists of a low noise dual-stage charge sensitive amplifier (CSA), a CR-(RC)4 semi-Gaussian shaper and a class-AB output buffer. The equivalent noise charge (ENC) of input PMOS transistor is optimized for 5 pF input capacitance and 1 μs peaking time using gm/ID design methodology. The gain can be adjusted from 100 mV/fC to 400 mV/fC and the peaking time can be adjusted from 1 μs to 4 μs. A 16-channel chip has been designed and fabricated in 0.35 μm 2P4M CMOS technology. The test results show that the chip works well and fully satisfies the design specifications. The ENC was measured to be 72 e + 26 e/pF at 1 μs peaking time and 86 e + 20 e/pF at 4 μs peaking time. The non-uniformity of the channel gain and ENC was less than ±12% and ±11% respectively for 16 channels in one chip. The chip was also tested with a pixelated CZT detector at room temperature. The measured energy resolution at 59.5 keV photopeak of 241Am and 122 keV photopeak of 57Co were 4.5% FWHM and 2.8% FWHM for the central area pixels, respectively.

  4. Development of Small-Pixel CZT Detectors for Future High-Resolution Hard X-ray Missions

    NASA Astrophysics Data System (ADS)

    Beilicke, Matthias

    Owing to recent breakthroughs in grazing incidence mirror technology, next-generation hard X-ray telescopes will achieve angular resolutions of between 5 and 10 arc seconds - about an order of magnitude better than that of the NuSTAR hard X-ray telescope. As a consequence, the next generation of hard X-ray telescopes will require pixelated hard X- ray detectors with pixels on a grid with a lattice constant of between 120 and 240 um. Additional detector requirements include a low energy threshold of less than 5 keV and an energy resolution of less than 1 keV. The science drivers for a high angular-resolution hard X-ray mission include studies and measurements of black hole spins, the cosmic evolution of super-massive black holes, AGN feedback, and the behavior of matter at very high densities. We propose a R&D research program to develop, optimize and study the performance of 100-200 um pixel pitch CdTe and Cadmium Zinc Telluride (CZT) detectors of 1-2 mm thickness. Our program aims at a comparison of the performance achieved with CdTe and CZT detectors, and the optimization of the pixel, steering grid, and guard ring anode patterns. Although these studies will use existing ASICs (Application Specific Integrated Circuits), our program also includes modest funds for the development of an ultra-low noise ASIC with a 2-D grid of readout pads that can be directly bonded to the 100-200 um pixel pitch CdTe and CZT detectors. The team includes the Washington University group (Prof. M. Beilicke and Co-I Prof. H.S.W. Krawczynski et al.), and co-investigator G. De Geronimo at Brookhaven National Laboratory (BNL). The Washington University group has a 10 year track record of innovative CZT detector R&D sponsored by the NASA Astronomy and Physics Research and Analysis (APRA) program. The accomplishments to date include the development of CZT detectors with pixel pitches between 350 um and 2.5 mm for the ProtoExist, EXIST, and X-Calibur hard X-ray missions with some of the best

  5. Simplification and validation of a large volume polyurethane foam sampler for the analysis of persistent hydrophobic compounds in drinking water.

    PubMed

    Choi, J W; Lee, J H; Moon, B S; Kannan, K

    2008-08-01

    The use of a large volume polyurethane foam (PUF) sampler was validated for rapid extraction of persistent organic pollutants (POPs), such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), in raw water and treated water from drinking water plants. To validate the recovery of target compounds in the sampling process, a (37)Cl-labeled standard was spiked into the 1st PUF plug prior to filtration. An accelerated solvent extraction method, as a pressurized liquid extractor (PLE), was optimized to extract the PUF plug. For sample preparation, tandem column chromatography (TCC) clean-up was used for rapid analysis. The recoveries of labeled compounds in the analytical method were 80-110% (n = 9). The optimized PUF-PLE-TCC method was applied in the analysis of raw water and treated potable water from seven drinking water plants in South Korea. The sample volume used was between 18 and 102 L for raw water at a flow rate of 0.4-2 L min(-1), 95 and 107 L for treated water at a flow rate of 1.5-2.2 L min(-1). Limit of quantitation (LOQ) was a function of sample volume and it decreased with increasing sample volume. The LOQ of PCDD/Fs in raw waters analyzed by this method was 3-11 times lower than that described using large-size disk-type solid phase extraction (SPE) method. The LOQ of PCDD/F congeners in raw water and treated water were 0.022-3.9 ng L(-1) and 0.018-0.74 ng L(-1), respectively. Octachlorinated dibenzo-p-dioxin (OCDD) was found in some raw water samples, while their concentrations were well below the tentative criterion set by the Japanese Environmental Ministry for drinking water. OCDD was below the LOQ in the treated drinking water.

  6. Low temperature system for a large volume multi-anvil press

    NASA Astrophysics Data System (ADS)

    Secco, Richard A.; Yong, Wenjun

    2016-12-01

    A new custom-designed system for a 3000 ton multi-anvil press has been developed to reach temperatures below room temperature at high pressures. The system was designed to remove heat selectively and conductively from the sample volume through six of the eight tungsten carbide (WC) cubes in direct contact with the octahedral pressure cell. The key components of the system include Cu cooling fins sandwiched between neighboring cube faces and the connected Cu heat exchange chamber through which liquid nitrogen flows. Currently, this system enables us to reach temperatures down to 220 K at pressures up to 8 GPa, but it can be easily modified to retain similar cooling capability at the highest pressure the press can reach (ca. 25 GPa).

  7. Neutron spectrometry with large volume, heavy-loaded superheated droplet detectors: a simple spin-off.

    PubMed

    Ramos, A R; Giuliani, F; Felizardo, M; Girard, T A; Morlat, T; Marques, J G; Oliveira, C; Limagne, D; Waysand, G; Fernandes, A C

    2005-01-01

    SIMPLE is a superheated droplet detector (SDD) experiment designed to search for the evidence of spin-dependent weakly interacting neutralino dark matter (WIMPs). SDDs, a type of emulsion detector, consist of a uniform suspension of superheated liquid droplets in a compliant material such as a polymeric or aqueous gel. We report on the first neutron spectrometry experiments with SIMPLE SDDs, a spin-off of the neutron detector calibrations performed at the Portuguese Research Reactor. SIMPLE SDDs differ from most SDDs available commercially as they have a 10 times higher loading factor, containing 10(3) times more freon than their commercial counterparts and a 100 times larger volume. We have analysed the response of SIMPLE SDDs to two quasi-monochromatic neutron beams of energies 54 and 144 keV obtained with passive filters. Results show that the characteristic peaks in the fluence distribution of both filters could be determined and their energy position obtained using a simple thermodynamic relation.

  8. Enrichment of diluted cell populations from large sample volumes using 3D carbon-electrode dielectrophoresis.

    PubMed

    Islam, Monsur; Natu, Rucha; Larraga-Martinez, Maria Fernanda; Martinez-Duarte, Rodrigo

    2016-05-01

    Here, we report on an enrichment protocol using carbon electrode dielectrophoresis to isolate and purify a targeted cell population from sample volumes up to 4 ml. We aim at trapping, washing, and recovering an enriched cell fraction that will facilitate downstream analysis. We used an increasingly diluted sample of yeast, 10(6)-10(2) cells/ml, to demonstrate the isolation and enrichment of few cells at increasing flow rates. A maximum average enrichment of 154.2 ± 23.7 times was achieved when the sample flow rate was 10 μl/min and yeast cells were suspended in low electrically conductive media that maximizes dielectrophoresis trapping. A COMSOL Multiphysics model allowed for the comparison between experimental and simulation results. Discussion is conducted on the discrepancies between such results and how the model can be further improved.

  9. Large Volume 18O-depleted Rhyolitic Volcanism: the Bruneau-Jarbidge Volcanic Field, Idaho

    NASA Astrophysics Data System (ADS)

    Boroughs, S.; Wolff, J.; Bonnichsen, B.; Godchaux, M. M.; Larson, P. B.

    2003-12-01

    The Bruneau-Jarbidge (BJ) volcanic field is located in southern Idaho at the intersection of the western and eastern arms of the Snake River Plain. The BJ region is an oval structural basin of about 6000 km2, and is likely a system of nested caldera and collapse structures similar to, though larger than, the Yellowstone Volcanic Plateau. BJ rocks are high-temperature rhyolite tuffs, high-temperature rhyolite lavas, and volumetrically minor basalts. Exposed volumes of individual rhyolite units range up to greater than 500 km3. We have analyzed feldspar and, where present, quartz from 30 rhyolite units emplaced throughout the history of the BJ center. All, including the Cougar Point Tuff, are 18O depleted (δ 18OFSP = -1.3 to 3.7‰ ), while petrographically, temporally, and chemically similar lavas erupted along the nearby Owyhee Front have "normal" rhyolite magmatic δ 18O values of 7 - 9‰ . There is no evidence for significant modification of δ 18O values by post-eruptive alteration. No correlation exists between δ 18O and age, magmatic temperature, major element composition or trace element abundances among depleted BJ rhyolites. The BJ and WSRP rhyolites possess the geochemical characteristics (depressed Al, Ca, Eu, and Sr contents, high Ga/Al and K/Na) expected of liquids derived from shallow melting of calc-alkaline granitoids with residual plagioclase and orthopyroxene (Patino-Douce, Geology v.25 p.743-746, 1997). The classic Yellowstone low δ 18O rhyolites are post-caldera collapse lavas, but at BJ, both lavas and caldera-forming ignimbrites are strongly 18O-depleted. The total volume of low δ 18O rhyolite may be as high as 10,000 km3, requiring massive involvement of meteoric-hydrothermally altered crust in rhyolite petrogenesis. Regional hydrothermal modification of the crust under the thermal influence of the Yellowstone hotspot apparently preceded voluminous rhyolite generation at Bruneau-Jarbidge.

  10. A large volume striped bass egg incubation chamber: design and comparison with a traditional method

    USGS Publications Warehouse

    Harper, C.J.

    2009-01-01

    I conducted a comparative study of a new jar design (experimental chamber) with a standard egg incubation vessel (McDonald jar). Experimental chambers measured 0.4 m in diameter by 1.3 m in height and had a volume of 200 L. McDonald hatching jars measured 16 cm in diameter by 45 cm in height and had a volume of 6 L. Post-hatch survival was estimated at 48, 96 and 144 h. Stocking rates resulted in an average egg density of 21.9 eggs ml-1 (range = 21.6 – 22.1) for McDonald jars and 10.9 eggs ml-1 (range = 7.0 – 16.8) for experimental chambers. I was unable to detect an effect of container type on survival to 48, 96 or 144 h. At 144 h striped bass fry survival averaged 37.3% for McDonald jars and 34.2% for experimental chambers. Survival among replicates was significantly different. Survival of striped bass significantly decreased between 96 and 144 h. Mean survival among replicates ranged from 12.4 to 57.3%. I was unable to detect an effect of initial stocking density on survival. Experimental jars allow for incubation of a larger number of eggs in a much smaller space. As hatchery production is often limited by space or water supply, experimental chambers offer an alternative to extending spawning activities, thereby reducing manpower and cost. However, the increase in the number of eggs per rearing container does increase the risk associated with catastrophic loss of a production unit. I conclude the experimental chamber is suitable for striped bass egg incubation.

  11. Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography.

    PubMed

    Förste, Alexander; Pfirrmann, Marco; Sachs, Johannes; Gröger, Roland; Walheim, Stefan; Brinkmann, Falko; Hirtz, Michael; Fuchs, Harald; Schimmel, Thomas

    2015-05-01

    There are only few quantitative studies commenting on the writing process in dip-pen nanolithography with lipids. Lipids are important carrier ink molecules for the delivery of bio-functional patters in bio-nanotechnology. In order to better understand and control the writing process, more information on the transfer of lipid material from the tip to the substrate is needed. The dependence of the transferred ink volume on the dwell time of the tip on the substrate was investigated by topography measurements with an atomic force microscope (AFM) that is characterized by an ultra-large scan range of 800 × 800 μm(2). For this purpose arrays of dots of the phospholipid1,2-dioleoyl-sn-glycero-3-phosphocholine were written onto planar glass substrates and the resulting pattern was imaged by large scan area AFM. Two writing regimes were identified, characterized of either a steady decline or a constant ink volume transfer per dot feature. For the steady state ink transfer, a linear relationship between the dwell time and the dot volume was determined, which is characterized by a flow rate of about 16 femtoliters per second. A dependence of the ink transport from the length of pauses before and in between writing the structures was observed and should be taken into account during pattern design when aiming at best writing homogeneity. The ultra-large scan range of the utilized AFM allowed for a simultaneous study of the entire preparation area of almost 1 mm(2), yielding good statistic results.

  12. Soft SUSY breaking parameters and RG running of squark and slepton masses in large volume Swiss Cheese compactifications

    NASA Astrophysics Data System (ADS)

    Misra, Aalok; Shukla, Pramod

    2010-03-01

    We consider type IIB large volume compactifications involving orientifolds of the Swiss Cheese Calabi-Yau WCP[1,1,1,6,9] with a single mobile space-time filling D3-brane and stacks of D7-branes wrapping the “big” divisor ΣB (as opposed to the “small” divisor usually done in the literature thus far) as well as supporting D7-brane fluxes. After reviewing our proposal of [1] (Misra and Shukla, 2010) for resolving a long-standing tension between large volume cosmology and phenomenology pertaining to obtaining a 10 GeV gravitino in the inflationary era and a TeV gravitino in the present era, and summarizing our results of [1] (Misra and Shukla, 2010) on soft supersymmetry breaking terms and open-string moduli masses, we discuss the one-loop RG running of the squark and slepton masses in mSUGRA-like models (using the running of the gaugino masses) to the EW scale in the large volume limit. Phenomenological constraints and some of the calculated soft SUSY parameters identify the D7-brane Wilson line moduli as the first two generations/families of squarks and sleptons and the D3-brane (restricted to the big divisor) position moduli as the two Higgses for MSSM-like models at TeV scale. We also discuss how the obtained open-string/matter moduli make it easier to impose FCNC constraints, as well as RG flow of off-diagonal squark mass(-squared) matrix elements.

  13. RADON DIAGNOSTIC MEASUREMENT GUIDANCE FOR LARGE BUILDINGS - VOLUME 1. TECHNICAL REPORT

    EPA Science Inventory

    The report discusses the development of radon diagnostic procedures and mitigation strategies applicable to a variety of large non-residential buildings commonly found in Florida. The investigations document and evaluate the nature of radon occurrence and entry mechanisms for rad...

  14. Systems definition study for shuttle demonstration flights of large space structures. Volume 3: Thermal analyses

    NASA Technical Reports Server (NTRS)

    1979-01-01

    the development of large space structure technology is discussed. A detailed thermal analysis of a model space fabricated 1 meter beam is presented. Alternative thermal coatings are evaluated, and deflections, stresses, and stiffness variations resulting from flight orientations and solar conditions are predicted.

  15. IMPLICATION FOR THE CORE-COLLAPSE SUPERNOVA RATE FROM 21 YEARS OF DATA OF THE LARGE VOLUME DETECTOR

    SciTech Connect

    Agafonova, N. Y.; Ashikhmin, V. V.; Dadykin, V. L.; Dobrynina, E. A.; Enikeev, R. I.; Malgin, A. S.; Aglietta, M.; Badino, G.; Bertoni, R.; Fulgione, W.; Galeotti, P.; Gomez, F.; Antonioli, P.; Bari, G.; Garbini, M.; Giusti, P.; Bressan, E.; Bruno, G.; Ghia, P. L.; Kemp, E. E-mail: fulgione@to.infn.it; Collaboration: LVD Collaboration; and others

    2015-03-20

    The Large Volume Detector (LVD) has been continuously taking data since 1992 at the INFN Gran Sasso National Laboratory. The LVD is sensitive to neutrino bursts from gravitational stellar collapses with full detection probability over the Galaxy. We have searched for neutrino bursts in LVD data taken over 7,335 days of operation. No evidence of neutrino signals has been found between 1992 June and 2013 December. The 90% C.L. upper limit on the rate of core collapse and failed supernova explosions out to distances of 25 kpc is found to be 0.114 yr{sup −1}.

  16. Large Deployable Reflector (LDR) system concept and technology definition study. Volume 1: Executive summary, analyses and trades, and system concepts

    NASA Astrophysics Data System (ADS)

    Agnew, Donald L.; Jones, Peter A.

    1989-04-01

    A study was conducted to define reasonable and representative large deployable reflector (LDR) system concepts for the purpose of defining a technology development program aimed at providing the requisite technological capability necessary to start LDR development by the end of 1991. This volume includes the executive summary for the total study, a report of thirteen system analysis and trades tasks (optical configuration, aperture size, reflector material, segmented mirror, optical subsystem, thermal, pointing and control, transportation to orbit, structures, contamination control, orbital parameters, orbital environment, and spacecraft functions), and descriptions of three selected LDR system concepts. Supporting information is contained in appendices.

  17. Large Deployable Reflector (LDR) system concept and technology definition study. Volume 1: Executive summary, analyses and trades, and system concepts

    NASA Technical Reports Server (NTRS)

    Agnew, Donald L.; Jones, Peter A.

    1989-01-01

    A study was conducted to define reasonable and representative large deployable reflector (LDR) system concepts for the purpose of defining a technology development program aimed at providing the requisite technological capability necessary to start LDR development by the end of 1991. This volume includes the executive summary for the total study, a report of thirteen system analysis and trades tasks (optical configuration, aperture size, reflector material, segmented mirror, optical subsystem, thermal, pointing and control, transportation to orbit, structures, contamination control, orbital parameters, orbital environment, and spacecraft functions), and descriptions of three selected LDR system concepts. Supporting information is contained in appendices.

  18. Reirradiation of Large-Volume Recurrent Glioma With Pulsed Reduced-Dose-Rate Radiotherapy

    SciTech Connect

    Adkison, Jarrod B.; Tome, Wolfgang; Seo, Songwon; Richards, Gregory M.; Robins, H. Ian; Rassmussen, Karl; Welsh, James S.; Mahler, Peter A.; Howard, Steven P.

    2011-03-01

    Purpose: Pulsed reduced-dose-rate radiotherapy (PRDR) is a reirradiation technique that reduces the effective dose rate and increases the treatment time, allowing sublethal damage repair during irradiation. Patients and Methods: A total of 103 patients with recurrent glioma underwent reirradiation using PRDR (86 considered to have Grade 4 at PRDR). PRDR was delivered using a series of 0.2-Gy pulses at 3-min intervals, creating an apparent dose rate of 0.0667 Gy/min to a median dose of 50 Gy (range, 20-60) delivered in 1.8-2.0-Gy fractions. The mean treatment volume was 403.5 {+-} 189.4 cm{sup 3} according to T{sub 2}-weighted magnetic resonance imaging and a 2-cm margin. Results: For the initial or upgraded Grade 4 cohort (n = 86), the median interval from the first irradiation to PRDR was 14 months. Patients undergoing PRDR within 14 months of the first irradiation (n = 43) had a median survival of 21 weeks. Those treated {>=}14 months after radiotherapy had a median survival of 28 weeks (n = 43; p = 0.004 and HR = 1.82 with a 95% CI ranging from 1.25 to 3.10). These data compared favorably to historical data sets, because only 16% of the patients were treated at first relapse (with 46% treated at the second relapse, 32% at the third or fourth relapse, and 4% at the fourth or fifth relapse). The median survival since diagnosis and retreatment was 6.3 years and 11.4 months for low-grade, 4.1 years and 5.6 months for Grade 3, and 1.6 years and 5.1 months for Grade 4 tumors, respectively, according to the initial histologic findings. Multivariate analysis revealed age at the initial diagnosis, initial low-grade disease, and Karnofsky performance score of {>=}80 to be significant predictors of survival after initiation of PRDR. Conclusion: PRDR allowed for safe retreatment of larger volumes to high doses with palliative benefit.

  19. Linear and cyclic methylsiloxanes in air by concurrent solvent recondensation-large volume injection-gas chromatography-mass spectrometry.

    PubMed

    Companioni-Damas, E Y; Santos, F J; Galceran, M T

    2014-01-01

    In the present work, a simple and fast method for the analysis of linear and cyclic methylsiloxanes in ambient air based on active sampling combined with gas chromatography - mass spectrometry (GC-MS) was developed. The retention efficiency of five sampling sorbents (activated coconut charcoal, Carbopack B, Cromosorb 102, Cromosorb 106 and Isolute ENV+) was evaluated and Isolute ENV+ was found to be the most effective. A volume of 2700 L of air can be sampled without significant losses of the most volatile methylsiloxanes. To improve the sensitivity of the GC-MS method, concurrent solvent recondensation - large volume injection (CSR-LVI), using volumes up to 30 µl of sample extract, is proposed and limits of quantification down to 0.03-0.45 ng m(-3), good linearity (r>0.999) and precision (RSD %<9%) were obtained. The developed method was applied to the analysis of ambient air. Concentrations of linear and cyclic methylsiloxanes in indoor air ranging from 3.9 to 319 ng m(-3) and between 48 and 292668 ng m(-3), were obtained, respectively, while levels from 6 to 22 ng m(-3) for linear and between 2.2 and 439 ng m(-3) for cyclic methylsiloxanes in outdoor air from Barcelona (Spain), were found.

  20. Particle-associated polycyclic aromatic hydrocarbons near power plants as determined by large volume injection--GC/MS.

    PubMed

    Evagelopoulos, V; Albanis, T A; Kodona, El; Zoras, S

    2010-06-01

    PM(10) and PM(2.5) samples were collected at two locations in the heavy industrialized prefecture of Kozani, in North-western Greece; in the open-cast mines of Klitos area and in the urban area of city of Kozani. The samples were collected by the use of low volume samplers, for a period of 1 year every 6 d. An analytical method has been adapted for determining 16 particle-bound polycyclic aromatic hydrocarbons (PAHs) in PM(10) and PM(2.5). Samples were collected on poly-tetra-fluorinated-ethylene (PTFE) filters using low volume samplers, considered to be ideal for trapping various organic pollutants including PAHs. The extraction has been made in two stages. Firstly, by reflux and then by using ultrasound bath. Chromatographic analysis has been carried out by GC/MS with programmable temperature vaporizers (PTV) injector and large volume injection (LVI) technique. Mean daily concentrations of B[a]Py in PM(10)-bound particles were 0.57 ng m(-3) in Kozani and 0.58 ng m(-3) at Klitos, while in PM(2.5)-bound PAHs were 0.35 ng m(-3) and 0.30 ng m(-3) respectively. We were able to verify the sources of PAHs by the use of diagnostic ratios, which indicate oil or/and coal burning as the, possible, major PAHs pollutant source(s).

  1. Large-area chromogenics: Materials and devices for transmittance control. Volume IS 4

    SciTech Connect

    Lampert, C.M.; Granqvist, C.G.

    1990-12-31

    Chromogenic materials can alter their optical properties in a persistent yet reversible manner when subjected to a change in external conditions such as irradiation intensity, temperature, or electric-field strength. In the future chromogenic materials may be used on large scale to regulate the throughput of radiant energy for windows in buildings and cars, so that comfortable lighting and temperature are maintained without excessive air conditioning. The purpose of this book is to give a broad coverage of large-area chromogenics and to discuss their applications. The book is divided into the following areas: applications; photochromic materials; thermochromic materials; inorganic electrochromic materials; inorganic electrochromic materials; organic electrochromic materials; conductors for ions and electrons in electrochromic devices; electrochromic devices; and liquid crystals materials and devices. Separate abstracts were prepared for 33 papers in this book.

  2. Large Deployable Reflector Science and Technology Workshop. Volume 2: Scientific Rationale and Technology Requirements

    NASA Technical Reports Server (NTRS)

    Hollenbach, D. (Editor)

    1983-01-01

    The scientific rationale for the large deployable reflector (LDR) and the overall technological requirements are discussed. The main scientific objectives include studies of the origins of planets, stars and galaxies, and of the ultimate fate of the universe. The envisioned studies require a telescope with a diameter of at least 20 m, diffraction-limited to wavelengths as short as 30-50 micron. In addition, light-bucket operation with 1 arcsec spatial resolution in the 2-4 microns wavelength region would be useful in studies of high-redshifted galaxies. Such a telescope would provide a large increase in spectroscopic sensitivity and spatial resolving power compared with existing or planned infrared telescopes.

  3. Study of auxiliary propulsion requirements for large space systems, volume 2

    NASA Technical Reports Server (NTRS)

    Smith, W. W.; Machles, G. W.

    1983-01-01

    A range of single shuttle launched large space systems were identified and characterized including a NASTRAN and loading dynamics analysis. The disturbance environment, characterization of thrust level and APS mass requirements, and a study of APS/LSS interactions were analyzed. State-of-the-art capabilities for chemical and ion propulsion were compared with the generated propulsion requirements to assess the state-of-the-art limitations and benefits of enhancing current technology.

  4. Extraterrestrial processing and manufacturing of large space systems. Volume 3: Executive summary

    NASA Technical Reports Server (NTRS)

    Miller, R. H.; Smith, D. B. S.

    1979-01-01

    Facilities and equipment are defined for refining processes to commercial grade of lunar material that is delivered to a 'space manufacturing facility' in beneficiated, primary processed quality. The manufacturing facilities and the equipment for producing elements of large space systems from these materials and providing programmatic assessments of the concepts are also defined. In-space production processes of solar cells (by vapor deposition) and arrays, structures and joints, conduits, waveguides, RF equipment radiators, wire cables, converters, and others are described.

  5. Extraterrestrial processing and manufacturing of large space systems, volume 1, chapters 1-6

    NASA Technical Reports Server (NTRS)

    Miller, R. H.; Smith, D. B. S.

    1979-01-01

    Space program scenarios for production of large space structures from lunar materials are defined. The concept of the space manufacturing facility (SMF) is presented. The manufacturing processes and equipment for the SMF are defined and the conceptual layouts are described for the production of solar cells and arrays, structures and joints, conduits, waveguides, RF equipment radiators, wire cables, and converters. A 'reference' SMF was designed and its operation requirements are described.

  6. No evidence of a threshold in traffic volume affecting road-kill mortality at a large spatio-temporal scale

    SciTech Connect

    Grilo, Clara; Ferreira, Flavio Zanchetta; Revilla, Eloy

    2015-11-15

    Previous studies have found that the relationship between wildlife road mortality and traffic volume follows a threshold effect on low traffic volume roads. We aimed at evaluating the response of several species to increasing traffic intensity on highways over a large geographic area and temporal period. We used data of four terrestrial vertebrate species with different biological and ecological features known by their high road-kill rates: the barn owl (Tyto alba), hedgehog (Erinaceus europaeus), red fox (Vulpes vulpes) and European rabbit (Oryctolagus cuniculus). Additionally, we checked whether road-kill likelihood varies when traffic patterns depart from the average. We used annual average daily traffic (AADT) and road-kill records observed along 1000 km of highways in Portugal over seven consecutive years (2003–2009). We fitted candidate models using Generalized Linear Models with a binomial distribution through a sample unit of 1 km segments to describe the effect of traffic on the probability of finding at least one victim in each segment during the study. We also assigned for each road-kill record the traffic of that day and the AADT on that year to test for differences using Paired Student's t-test. Mortality risk declined significantly with traffic volume but varied among species: the probability of finding road-killed red foxes and rabbits occurs up to moderate traffic volumes (< 20,000 AADT) whereas barn owls and hedgehogs occurred up to higher traffic volumes (40,000 AADT). Perception of risk may explain differences in responses towards high traffic highway segments. Road-kill rates did not vary significantly when traffic intensity departed from the average. In summary, we did not find evidence of traffic thresholds for the analysed species and traffic intensities. We suggest mitigation measures to reduce mortality be applied in particular on low traffic roads (< 5000 AADT) while additional measures to reduce barrier effects should take into account

  7. Characteristics of surface-wave and volume-wave plasmas produced with internally mounted large-area planar microwave launcher

    SciTech Connect

    Nagatsu, Masaaki; Naito, Katsutoshi; Ogino, Akihisa; Ninomiya, Keigo; Nanko, Shohei

    2005-10-17

    We studied discharge characteristics of microwave plasmas excited with a large-area planar microwave launcher installed internally in a 600-mm-diam cylindrical vacuum chamber. With the microwave power less than roughly 400 W, we demonstrated the large volumetric volume-wave plasma (VWP) spread in the entire chamber at a pressure of 14-27 Pa in He. Above 400 W, the plasma discharge made a sudden transition to higher-density, uniform surface-wave plasma (SWP) having a spatial uniformity of {+-}3.5% over 300 mm in diameter. Electron energy probability functions in the downstream region were studied using Langmuir probe measurements with Druyvesteyn method in both the SWP and VWP discharges.

  8. Magnetostructural martensitic transformations with large volume changes and magneto-strains in all-d-metal Heusler alloys

    NASA Astrophysics Data System (ADS)

    Wei, Z. Y.; Liu, E. K.; Li, Y.; Han, X. L.; Du, Z. W.; Luo, H. Z.; Liu, G. D.; Xi, X. K.; Zhang, H. W.; Wang, W. H.; Wu, G. H.

    2016-08-01

    The all-d-metal Mn2-based Heusler ferromagnetic shape memory alloys Mn50Ni40-xCoxTi10 (x = 8 and 9.5) are realized. With a generic comparison between d-metal Ti and main-group elements in lowering the transformation temperature, the magnetostructural martensitic transformations are established by further introducing Co to produce local ferromagnetic Mn-Co-Mn configurations. A 5-fold modulation and (3, -2) stacking of [00 10] of martensite are determined by X-ray diffraction and HRTEM analysis. Based on the transformation, a large magneto-strain of 6900 ppm and a large volume change of -2.54% are observed in polycrystalline samples, which makes the all-d-metal magnetic martensitic alloys of interest for magnetic/pressure multi-field driven applications.

  9. Large-volume data delivery from low-Earth orbit to ground using efficient single-mode optical receivers

    NASA Astrophysics Data System (ADS)

    Robinson, B. S.; Schieler, C. M.; Boroson, D. M.

    2016-03-01

    Space systems operating in low-Earth orbit are often constrained by how much data can be delivered from space to ground. Traditional data delivery approaches are often limited by either large link losses associated with transmission via a geosynchronous relay satellite or short contact times and spectrum-constrained data rates associated with direct-to-Earth radio-frequency links. Direct-to-Earth optical communication links from low-Earth orbit based on fiber telecommunications technologies that can operate at high data rates (> 100 Gb/s per wavelength channel) can enable the delivery of extremely large volumes of data from space to ground. We analyze the performance of such systems and discuss the performance gains that are enabled by coupling the received signal to an efficient single-mode-fiber-based receiver, even in the presence of turbulence-induced losses.

  10. Multiple myeloma patients receiving large volume leukapheresis efficiently yield enough CD34+ cells to allow double transplants.

    PubMed

    Zubair, A C; Rymer, R; Young, J; Keeton, U; Befort, R; Nolot, B; Evans, C; Bleach, T; Torloni, A

    2009-01-01

    Current protocols for myeloma patients require more than one autologous transplant. We performed a retrospective study to determine the cost-effectiveness of large volume leukapheresis (LVL) compared with standard volume leukapheresis (SVL) collection when two transplants are required. We evaluated 87 patients who underwent a cumulative total of 260 LVL and SVL collections. The median product volume per collection was 356 ml for LVL, and this was significantly higher than the median product volume per collection for SVL (median 149.5 ml, P < 0.001). The median total CD34+ cell yield/kg was 6.4 x 10(6) for LVL and 5.2 x 10(6) for SVL. This difference was statistically significant (P = 0.005). Because the target CD34+ cell dose for a single transplant was 3 x 10(6)/kg at our institution, overall the LVL yields enough CD34+ cells that could allow for two transplants. Therefore, more patients in the LVL group were able to undergo a potential second transplant. Because of the reserved cells for a second transplant, LVL patients received significantly less CD34+ cell/kg per transplant than the patients in SVL group (P = <0.001). As a result, LVL group had statistically significant but clinically insignificant delay in neutrophil (P = <0.001) and platelet (P = 0.02) engraftments. Additionally, using LVL instead of SVL to collect >or=6 x 10(6)/kg CD34+ cells may potentially save $7,497 per patient. We therefore conclude that LVL is the method of choice for collection of multiple myeloma patients when two transplants are anticipated.

  11. Large-volume volcanic edifice failures in Central America and associated hazards

    USGS Publications Warehouse

    Siebert, Lee; Alvarado, Guillermo E.; Vallance, James W.; van Wyk de Vries, Benjamin

    2006-01-01

    Edifice-collapse phenomena have, to date, received relatively little attention in Central America, although ∼40 major collapse events (≥0.1 km3) from about two dozen volcanoes are known or inferred in this volcanic arc. Volcanoes subjected to gravitational failure are concentrated at the arc's western and eastern ends. Failures correlate positively with volcano elevation, substrate elevation, edifice height, volcano volume, and crustal thickness and inversely with slab descent angle. Collapse orientations are strongly influenced by the direction of slope of the underlying basement, and hence are predominately perpendicular to the arc (preferentially to the south) at its extremities and display more variable failure directions in the center of the arc.The frequency of collapse events in Central America is poorly constrained because of the lack of precise dating of deposits, but a collapse interval of ∼1000–2000 yr has been estimated during the Holocene. These high-impact events fortunately occur at low frequency, but the proximity of many Central American volcanoes to highly populated regions, including some of the region's largest cities, requires evaluation of their hazards. The primary risks are from extremely mobile debris avalanches and associated lahars, which in Central America have impacted now-populated areas up to ∼50 km from a source volcano. Lower probability risks associated with volcanic edifice collapse derive from laterally directed explosions and tsunamis. The principal hazards of the latter here result from potential impact of debris avalanches into natural or man-made lakes. Much work remains on identifying and describing debris-avalanche deposits in Central America. The identification of potential collapse sites and assessing and monitoring the stability of intact volcanoes is a major challenge for the next decade.

  12. Large-volume volcanic edifi ce failures in Central America and associated hazards

    USGS Publications Warehouse

    Siebert, L.; Alvarado, Guillermo E.; Vallance, J.W.; Van Wyk de Vries, B.

    2006-01-01

    Edifi ce-collapse phenomena have, to date, received relatively little attention in Central America, although ??40 major collapse events (??0.1 km3) from about two dozen volcanoes are known or inferred in this volcanic arc. Volcanoes subjected to gravitational failure are concentrated at the arc's western and eastern ends. Failures correlate positively with volcano elevation, substrate elevation, edifi ce height, volcano volume, and crustal thickness and inversely with slab descent angle. Collapse orientations are strongly infl uenced by the direction of slope of the underlying basement, and hence are predominately perpendicular to the arc (preferentially to the south) at its extremities and display more variable failure directions in the center of the arc. The frequency of collapse events in Central America is poorly constrained because of the lack of precise dating of deposits, but a collapse interval of ??1000-2000 yr has been estimated during the Holocene. These high-impact events fortunately occur at low frequency, but the proximity of many Central American volcanoes to highly populated regions, including some of the region's largest cities, requires evaluation of their hazards. The primary risks are from extremely mobile debris avalanches and associated lahars, which in Central America have impacted now-populated areas up to ??50 km from a source volcano. Lower probability risks associated with volcanic edifi ce collapse derive from laterally directed explosions and tsunamis. The principal hazards of the latter here result from potential impact of debris avalanches into natural or man-made lakes. Much work remains on identifying and describing debris-avalanche deposits in Central America. The identifi cation of potential collapse sites and assessing and monitoring the stability of intact volcanoes is a major challenge for the next decade. ?? 2006 Geological Society of America.

  13. Hierarchical storage of large volume of multidector CT data using distributed servers

    NASA Astrophysics Data System (ADS)

    Ratib, Osman; Rosset, Antoine; Heuberger, Joris; Bandon, David

    2006-03-01

    Multidector scanners and hybrid multimodality scanners have the ability to generate large number of high-resolution images resulting in very large data sets. In most cases, these datasets are generated for the sole purpose of generating secondary processed images and 3D rendered images as well as oblique and curved multiplanar reformatted images. It is therefore not essential to archive the original images after they have been processed. We have developed an architecture of distributed archive servers for temporary storage of large image datasets for 3D rendering and image processing without the need for long term storage in PACS archive. With the relatively low cost of storage devices it is possible to configure these servers to hold several months or even years of data, long enough for allowing subsequent re-processing if required by specific clinical situations. We tested the latest generation of RAID servers provided by Apple computers with a capacity of 5 TBytes. We implemented a peer-to-peer data access software based on our Open-Source image management software called OsiriX, allowing remote workstations to directly access DICOM image files located on the server through a new technology called "bonjour". This architecture offers a seamless integration of multiple servers and workstations without the need for central database or complex workflow management tools. It allows efficient access to image data from multiple workstation for image analysis and visualization without the need for image data transfer. It provides a convenient alternative to centralized PACS architecture while avoiding complex and time-consuming data transfer and storage.

  14. Study of stress-strain and volume change behavior of emplaced municipal solid waste using large-scale triaxial testing.

    PubMed

    Ramaiah, B J; Ramana, G V

    2017-01-27

    The article presents the stress-strain and volume change behavior, shear strength and stiffness parameters of landfilled municipal solid waste (MSW) collected from two dump sites located in Delhi, India. Over 30 drained triaxial compression (TXC) tests were conducted on reconstituted large-scale specimens of 150mm diameter to study the influence of fiber content, age, density and confining pressure on the shear strength of MSW. In addition, a few TXC tests were also conducted on 70mm diameter specimen to examine the effect of specimen size on the mobilized shear strength. It is observed that the fibrous materials such as textiles and plastics, and their percentage by weight have a significant effect on the stress-strain-volume change behavior, shear strength and stiffness of solid waste. The stress-strain-volume change behavior of MSW at Delhi is qualitatively in agreement with the behavior reported for MSW from different countries. Results of large-scale direct shear tests conducted on MSW with an identical composition used for TXC tests revealed the cross-anisotropic behavior as reported by previous researchers. Effective shear strength parameters of solid waste evaluated from this study is best characterized by ϕ'=39° and c'=0kPa for the limiting strain-based failure criteria of K0=0.3+5% axial strain and are in the range of the data reported for MSW from different countries. Data presented in this article is useful for the stress-deformation and stability analysis of the dump sites during their operation as well as closure plans.

  15. Systems definition study for shuttle demonstration flights of large space structures, Volume 2: Technical Report

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The development of large space structure (LSS) technology is discussed, with emphasis on space fabricated structures which are automatically manufactured in space from sheet-strip materials and assembled on-orbit. It is concluded that an LSS flight demonstration using an Automated Beam Builder and the orbiter as a construction base, could be performed in the 1983-1984 time period. The estimated cost is $24 million exclusive of shuttle launch costs. During the mission, a simple space platform could be constructed in-orbit to accommodate user requirements associated with earth viewing and materials exposure experiments needs.

  16. Large-volume sample stacking-capillary electrophoresis used for the determination of 3-nitrotyrosine in rat urine.

    PubMed

    Maeso, Nuria; Cifuentes, Alejandro; Barbas, Coral

    2004-09-25

    Large-volume sample stacking using the electroosmotic flow (EOF) pump technique has been investigated for the quantification of 3-nitrotyrosine in urine of diabetic rats. The best separation conditions for these highly complex samples were obtained using capillary electrophoresis (CE) in the reversed polarity mode (i.e., injecting at the cathode and detecting at the anode) using cetyltrimethylammonium bromide (CTAB) in the running buffer. The optimum CE separation conditions were achieved using a phosphate buffer prepared with 0.15M phosphoric acid and 0.5 mM CTAB adjusted to pH 6.4 with sodium hydroxide. In such CE conditions, the limit of detection (LOD) was 1.77 microM for 3-nitrotyrosine with normal injection mode, meanwhile with the large-volume sample stacking technique a more than 20-fold improvement was observed (i.e., LOD = 0.08 microM was obtained) without noticeable loss of resolution. This value allowed the detection of 3-nitrotyrosine in urine from diabetic rats. To our knowledge, this work is one of the few applications showing the great possibilities of these stacking procedures to analyse biological samples by CE.

  17. Boron-doped diamond heater and its application to large-volume, high-pressure, and high-temperature experiments.

    PubMed

    Shatskiy, Anton; Yamazaki, Daisuke; Morard, Guillaume; Cooray, Titus; Matsuzaki, Takuya; Higo, Yuji; Funakoshi, Ken-ichi; Sumiya, Hitoshi; Ito, Eiji; Katsura, Tomoo

    2009-02-01

    A temperature of 3500 degrees C was generated using a diamond resistance heater in a large-volume Kawai-type high-pressure apparatus. Re and LaCrO(3) have conventionally been used for heaters in high-pressure studies but they cannot generate temperatures higher than 2900 degrees C and make in situ x-ray observations difficult due to their high x-ray absorption. Using a boron-doped diamond heater overcomes these problems and achieves stable temperature generation for pressure over 10 GPa. The heater starting material is a cold-compressed mixture of graphite with boron used to avoid the manufacturing difficulties due to the extreme hardness of diamond. The diamond heater was synthesized in situ from the boron-graphite mixture at temperature of 1600+/-100 degrees C and pressure of 20 GPa. By using the proposed technique, we have employed the diamond heater for high-temperature generation in a large-volume high-pressure apparatus. Achievement of temperatures above 3000 degrees C allows us to measure the melting points of the important constituents in earth's mantle (MgSiO(3), SiO(2), and Al(2)O(3)) and core (Fe and Ni) at extremely high pressures.

  18. Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps

    SciTech Connect

    Henager, Charles H.; Gao, Fei; Hu, Shenyang Y.; Lin, Guang; Bylaska, Eric J.; Zabaras, Nicholas

    2012-11-01

    This one-year, study topic project will survey and investigate the known state-of-the-art of modeling and simulation methods suitable for performing fine-scale, fully 3-D modeling, of the growth of CZT crystals at the melt-solid interface, and correlating physical growth and post-growth conditions with generation and incorporation of defects into the solid CZT crystal. In the course of this study, this project will also identify the critical gaps in our knowledge of modeling and simulation techniques in terms of what would be needed to be developed in order to perform accurate physical simulations of defect generation in melt-grown CZT. The transformational nature of this study will be, for the first time, an investigation of modeling and simulation methods for describing microstructural evolution during crystal growth and the identification of the critical gaps in our knowledge of such methods, which is recognized as having tremendous scientific impacts for future model developments in a wide variety of materials science areas.

  19. Construction and testing of a pixellated CZT detector and shield for a hard x-ray astronomy balloon flight

    NASA Astrophysics Data System (ADS)

    Bloser, Peter F.; Narita, Tomohiko; Jenkins, Jonathan A.; Grindlay, Jonathan E.

    2000-12-01

    We report on the construction and laboratory testing of pixellated CZT detectors mounted in a flip-chip, tiled fashion and read out by an ASIC, as required for proposed hard X-ray astronomy missions. Two 10 mm X 10 mm X 5 mm detectors were fabricated, one out of standard eV Products high-pressure Bridgman CZT and one out of IMARAD horizontal Bridgman CZT. Each was fashioned with a 4 X 4 array of gold pixels on 2.5 mm pitch with a surrounding guard ring. The detectors were mounted side by side on a carrier card, such that the pixel pitch was preserved, and read out by a 32-channel VA-TA ASIC from IDE AS Corp. controlled by a PC/104 single-board computer. A passive shield/collimator surrounded by plastic scintillator encloses the detectors on five sides and provides an approximately 40 degree field of view. Thus this experiment tests key techniques required for future hard X-ray survey instruments. The experiment was taken to Ft. Sumner, NM in May 2000 in preparation for a scientific balloon flight aboard the joint Harvard-MSFC EXITE2/HERO payload. Although we did not receive a flight opportunity, and are currently scheduled to fly in September 2000, we present our calibration data in the flight configuration together with data analysis techniques and simulations of the expected flight background spectrum.

  20. Requirements for a mobile communications satellite system. Volume 3: Large space structures measurements study

    NASA Technical Reports Server (NTRS)

    Akle, W.

    1983-01-01

    This study report defines a set of tests and measurements required to characterize the performance of a Large Space System (LSS), and to scale this data to other LSS satellites. Requirements from the Mobile Communication Satellite (MSAT) configurations derived in the parent study were used. MSAT utilizes a large, mesh deployable antenna, and encompasses a significant range of LSS technology issues in the areas of structural/dynamics, control, and performance predictability. In this study, performance requirements were developed for the antenna. Special emphasis was placed on antenna surface accuracy, and pointing stability. Instrumentation and measurement systems, applicable to LSS, were selected from existing or on-going technology developments. Laser ranging and angulation systems, presently in breadboard status, form the backbone of the measurements. Following this, a set of ground, STS, and GEO-operational were investigated. A third scale (15 meter) antenna system as selected for ground characterization followed by STS flight technology development. This selection ensures analytical scaling from ground-to-orbit, and size scaling. Other benefits are cost and ability to perform reasonable ground tests. Detail costing of the various tests and measurement systems were derived and are included in the report.

  1. Volumetric leak detection in large underground storage tanks. Volume 2. Appendices a through e

    SciTech Connect

    Starr, J.W.; Wise, R.F.; Maresca, J.W.

    1991-08-01

    The program of experiments conducted at Griffiss Air Force Base was devised to expand the understanding of large underground storage tank behavior as it impacts the performance of volumetric leak detection testing. The report addresses three important questions about testing the larger underground storage tanks for leaks. First, can the EPA regulatory standards be met when volumetric methods are used to test tanks up to 190,000 L (50,000 gal) in capacity. Second, what is the precision required of the temperature and level sensors and what is the minimum duration of the data collection period in order for a volumetric system to accurately test larger tanks, particularly those that are partially filled. Third, what are the important features of a volumetric system that meets or exceeds the regulatory performance standards. The document presents the results of experiments conducted on 190,000-L (50,000-gal) underground storage tanks (USTs) to determine how to test large tanks for leaks with volumetric leak detection systems. The work reported in the document has applications to the UST release detection technical standards in CFR 280 Subpart D.

  2. Assessing the Feasibility of Large-Scale Countercyclical Public Job-Creation. Final Report, Volume II. Activities Suitable for Public Job-Creation and Their Characteristics.

    ERIC Educational Resources Information Center

    Urban Inst., Washington, DC.

    This second of a three-volume report of a study done to assess the feasibility of large-scale, countercyclical public job creation contains chapter 2 of the report on the methods and findings with respect to job-creating activities, their job-creation potential, and related characteristics. (Volume 1, comprised of the report's first chapter,…

  3. Assessing the Feasibility of Large-Scale Countercyclical Public Job-Creation. Final Report, Volume III. Selected Implications of Public Job-Creation.

    ERIC Educational Resources Information Center

    Urban Inst., Washington, DC.

    This last of a three-volume report of a study done to assess the feasibility of large-scale, countercyclical public job creation covers the findings regarding the priorities among projects, indirect employment effects, skill imbalances, and administrative issues; and summarizes the overall findings, conclusions, and recommendations. (Volume 1,…

  4. Critical joints in large composite primary aircraft structures. Volume 2: Technology demonstration test report

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of four large composite multirow bolted joint tests are presented. The tests were conducted to demonstrate the technology for critical joints in highly loaded composite structure and to verify the analytical methods that were developed throughout the program. The test consisted of a wing skin-stringer transition specimen representing a stringer runout and skin splice on the wing lower surface at the side of the fuselage attachment. All tests were static tension tests. The composite material was Toray T-300 fiber with Ciba-Geigy 914 resin in 10 mil tape form. The splice members were metallic, using combinations of aluminum and titanium. Discussions are given of the test article, instrumentation, test setup, test procedures, and test results for each of the four specimens. Some of the analytical predictions are also included.

  5. Critical joints in large composite primary aircraft structures. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted at Douglas Aircraft Company to develop the technology for critical joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. In fulfilling this objective, analytical procedures for joint design and analysis were developed during Phase 1 of the program. Tests were conducted at the element level to supply the empirical data required for methods development. Large composite multirow joints were tested to verify the selected design concepts and for correlation with analysis predictions. The Phase 2 program included additional tests to provide joint design and analysis data, and culminated with several technology demonstration tests of a major joint area representative of a commercial transport wing. The technology demonstration program of Phase 2 is discussed. The analysis methodology development, structural test program, and correlation between test results and analytical strength predictions are reviewed.

  6. Study of electrical and chemical propulsion systems for auxiliary propulsion of large space systems, volume 2

    NASA Technical Reports Server (NTRS)

    Smith, W. W.

    1981-01-01

    The five major tasks of the program are reported. Task 1 is a literature search followed by selection and definition of seven generic spacecraft classes. Task 2 covers the determination and description of important disturbance effects. Task 3 applies the disturbances to the generic spacecraft and adds maneuver and stationkeeping functions to define total auxiliary propulsion systems requirements for control. The important auxiliary propulsion system characteristics are identified and sensitivities to control functions and large space system characteristics determined. In Task 4, these sensitivities are quantified and the optimum auxiliary propulsion system characteristics determined. Task 5 compares the desired characteristics with those available for both electrical and chemical auxiliary propulsion systems to identify the directions technology advances should take.

  7. Earth matter effects on supernova neutrinos in large-volume detectors

    NASA Astrophysics Data System (ADS)

    Borriello, Enrico

    2013-04-01

    Neutrino oscillations in the Earth matter may introduce peculiar modulations in the supernova (SN) neutrino spectra. The detection of this effect has been proposed as diagnostic tool for the neutrino mass hierarchy. We perform an updated study on the observability of this effect at large next-generation underground detectors (i.e., 0.4 Mton water Cherenkov, 50 kton scintillation and 100 kton liquid Argon detectors) based on neutrino fluxes from state-of-the-art SN simulations and accounting for statistical fluctuations via Montecarlo simulations. Since the average energies predicted by recent simulations are lower than previously expected and a tendency towards the equalization of the neutrino fluxes appears during the SN cooling phase, the detection of the Earth matter effect will be more challenging than expected from previous studies. We find that none of the proposed detectors shall be able to detect the Earth modulation for the neutrino signal of a typical galactic SN at 10 kpc. It should be observable in a 100 kton liquid Argon detector for a SN at few kpc and all three detectors would clearly see the Earth signature for very close-by stars only (d˜200 pc).

  8. Study of auxiliary propulsion requirements for large space systems. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Smith, W. W.; Machles, G. W.

    1983-01-01

    An insight into auxiliary propulsion systems (APS) requirements for large space systems (LSS) launchable by a single shuttle is presented. In an effort to scope the APS requirements for LSS, a set of generic LSSs were defined. For each generic LSS class a specific structural configuration, representative of that most likely to serve the needs of the 1980's and 1990's was defined. The environmental disturbance forces and torques which would be acting on each specific structural configuration in LEO and GEO orbits were then determined. Auxiliary propulsion requirements were determined as a function of: generic class specific configuration, size and openness of structure, orbit, angle of orientation, correction frequency, duty cycle, number and location of thrusters and direction of thrusters and APS/LSS interactions. The results of this analysis were used to define the APS characteristics of: (1) number and distribution of thrusters, (2) thruster modulation, (3) thrust level, (4) mission energy requirements, (5) total APS mass component breakdown, and (6) state of the art adequacy/deficiency.

  9. Does Size Really Matter? Analysis of the Effect of Large Fibroids and Uterine Volumes on Complication Rates of Uterine Artery Embolisation

    SciTech Connect

    Parthipun, A. A. Taylor, J.; Manyonda, I.; Belli, A. M.

    2010-10-15

    The purpose of this study was to determine whether there is a correlation between large uterine fibroid diameter, uterine volume, number of vials of embolic agent used and risk of complications from uterine artery embolisation (UAE). This was a prospective study involving 121 patients undergoing UAE embolisation for symptomatic uterine fibroids at a single institution. Patients were grouped according to diameter of largest fibroid and uterine volume. Results were also stratified according to the number of vials of embolic agent used and rate of complications. No statistical difference in complication rate was demonstrated between the two groups according to diameter of the largest fibroid (large fibroids were classified as {>=}10 cm; Fisher's exact test P = 1.00), and no statistical difference in complication rate was demonstrated according to uterine volume (large uterine volume was defined as {>=}750 cm{sup 3}; Fisher's exact test P = 0.70). 84 of the 121 patients had documentation of the number of vials used during the procedure. Patients were divided into two groups, with {>=}4 used defined as a large number of embolic agent. There was no statistical difference between these two groups and no associated increased risk of developing complications. This study showed no increased incidence of complications in women with large-diameter fibroids or uterine volumes as defined. In addition, there was no evidence of increased complications according to quantity of embolic material used. Therefore, UAE should be offered to women with large fibroids and uterine volumes.

  10. A magnetic sorbent for the efficient and rapid extraction of organic micropollutants from large-volume environmental water samples.

    PubMed

    Zhang, Mancheng; Zhou, Qing; Li, Aimin; Shuang, Chendong; Wang, Wei; Wang, Mengqiao

    2013-11-05

    A magnetic solid-phase extraction (MSPE) method based on a novel magnetic sorbent was proposed for the extraction of target compounds from large-volume water samples. First, magnetic hypercrosslinked microspheres (NAND-1) were prepared via membrane emulsification-suspension polymerization and post crosslinking reaction. To ensure that the Fe3O4 nanoparticles could completely pass through the membrane without blocking the pores, oleic acid was used to modify the Fe3O4 nanoparticles, which enhanced lipophilicity and monodispersity of the magnetite nanoparticles. The obtained NAND-1 microspheres exhibited super paramagnetic characteristics and excellent magnetic responsiveness with a saturation magnetization of 2.53 emu/g. In addition, a uniform particle size (~8 μm) and a large average surface area (1303.59 m(2)/g) were also observed, which were both beneficial for the extraction of the target compounds. Thus, NAND-1 has the potential to simultaneously exhibit good extraction efficiencies toward different types of organic micropollutants (OMPs), including triazines, carbamazepine and diethyl phthalate. The conditions of the MSPE based on NAND-1 were optimized by single factor and orthogonal design experiments. This MSPE method needed only a small amount of sorbent (50mg/L) for the extraction of OMPs from a large-volume aquatic sample (5L) and reached equilibrium in a short amount of time (30 min). Moreover, the solution volume, the pH, and the salinity had insignificant influences on the extraction of the eight target OMPs. Under the optimum conditions, the recoveries of the eight OMPs calculated by analyzing the spiked samples were from 91.7% to 99.4%. The NAND-1 could be recycled ten times and still achieve recoveries of the eight OMPs higher than 86%. The limits of detection of the eight OMPs ranged from 1.76 to 27.56 ng/L, and the limits of quantification were from 5.71 to 92.05 ng/L. These results indicated that the proposed method, based on the use of NAND-1

  11. Determination of acrylamide in drinking water by large-volume direct injection and ion-exclusion chromatography-mass spectrometry.

    PubMed

    Cavalli, S; Polesello, S; Saccani, G

    2004-06-11

    Acrylamide, a known neurotoxin and putative human carcinogen, has been included among the substances to be monitored in drinking water according to the European Union Directive 98/83 on potable water. This paper reports a new method based on the combination of ion-exclusion chromatographic separation and MS detection. Samples of drinking water have been directly injected in the microbore ICE-AS1 column and detected in the selected-ion monitoring mode by a single quadrupole system with electrospray ionization. Chromatographic conditions, such as eluent composition and flow rate, have been optimized by a central composite design experiment. Statistical analysis of data showed that the amount of acetonitrile fraction in the eluent mixture, composed by acetonitrile and formic acid solution, is the variable that most influences retention of the acrylamide peak. After optimization of MS detection parameters, this method has been validated for spiked drinking water samples. The effect of large-volume injection (up to 500 microl) has been also explored. Linearity was evaluated from 0.5 to 5 microg l(-1). Repeatability, expressed as R.S.D., was 16 and 12% at 0.5 and 1 microg l(-1) respectively. The limit of detection was 0.20 ppb with 500 microl injection volume.

  12. Large-volume excitation of air, argon, nitrogen and combustible mixtures by thermal jets produced by nanosecond spark discharges

    NASA Astrophysics Data System (ADS)

    Stepanyan, Sergey; Hayashi, Jun; Salmon, Arthur; Stancu, Gabi D.; Laux, Christophe O.

    2017-04-01

    This work presents experimental observations of strong expanding thermal jets following the application of nanosecond spark discharges. These jets propagate in a toroidal shape perpendicular to the interelectrode axis, with high velocities of up to 30 m s‑1 and over distances of the order of a cm. Their propagation length is much larger than the thermal expansion region produced by the conventional millisecond sparks used in car engine ignition, thus greatly improving the volumetric excitation of gas mixtures. The shape and velocity of the jets is found to be fairly insensitive to the shape of the electrodes. In addition, their spatial extent is found to increase with the number of nanosecond sparks and with the discharge voltage, and to decrease slightly with the pressure between 1 and 7 atm at constant applied voltage. Finally, this thermal jet phenomenon is observed in experiments conducted with many types of gas mixtures, including air, nitrogen, argon, and combustible CH4/air mixtures. This makes nanosecond repetitively pulsed discharges particularly attractive for aerodynamic flow control or plasma-assisted combustion because of their ability to excite large volumes of gas, typically about 100 times the volume of the discharge.

  13. Eruption and emplacement of flood basalt. An example from the large-volume Teepee Butte Member, Columbia River Basalt Group

    SciTech Connect

    Reidel, S.P. ); Tolan, T.L. )

    1992-12-01

    Flows of the Teepee Butte Member, Grande Ronde Basalt, issued from a vent system in southeastern Washington, northeastern Oregon, and western Idaho. Three distinct basalt flows were erupted: the Limekiln Rapids flow, the Joseph Creek flow, and the Pruitt Draw flow. Together these mappable flows cover more than 52,000 km[sup 2] and have a volume exceeding 5,000 km[sup 3]. A portion of the vent system for the Joseph Creek flow is exposed in cross section in Joseph Canyon, Washington; it is one of the best preserved Columbia River Basalt Group vent complexes known. The vent complex is about 1 km in cross section, 30 m high, and composed of deposits characteristic of Hawaiian-type volcanism. The vent is asymmetrical; the eastern rampart consists of intercalated pyroclastic deposits and thin pahoehoe flows; the western rampart is composed wholly of pahoehoe flows. Flows of the Teepee Butte Member are compositionally homogeneous and were emplaced as sheet flows, each having several local flow units. Our study supports the importance of linear vent systems and the westward Palouse Slope, along with the large-volume lava flows, in controlling the distribution of Columbia River Basalt Group flows. Other factors, including the number of active fissure segments and topography, modified the shape of the flows and the number of flow units. 45 refs., 19 figs., 2 tabs.

  14. Thermo-mechanical response of poly(methyl methacrylate) (PMMA) large volumes exposed to time-dependent environmental conditions

    NASA Astrophysics Data System (ADS)

    Fraldi, M.; Esposito, L.; Perrella, G.; Cutolo, A.

    2014-02-01

    Low thermal conductivity and elevated absorbance of large bulky volumes of poly(methyl methacrylate) (PMMA) exposed to moderately aggressive environmental conditions may cooperate to determine critical mechanical conditions, kindling unexpected high thermal stresses values which lead the material to failure. From the engineering point of view, this can be explained as the result of two concomitant phenomena which activate a cascade of events: very sharp thermal gradients engendered by transient thermal processes induced by cyclic environmental conditions, combined with significant bulk heat generation due to the high thermal inertia of massive PMMA volumes, in turn aggravating the steepness of the thermal gradients, may in fact ingenerate severe stress regimes, potentially undermining the structural stability of the material. Moving from these considerations, the present study is aimed to investigate possible rupture of PMMA blocks experiencing heating processes as a consequence of their exposure to outdoor cyclic environmental conditions. The problem is approached by means of both rigorous analytical arguments and the Finite Element based numerical methods, finally exploiting the theoretical outcomes to formulate a hypothesis which might explain the still unclear phenomenon of the sudden breaking of the PMMA structure, named Huge Wine Glass and designed by the world famous Japanese architect Toyo Ito, which occurred in Pescara (Italy) in 2009.

  15. Development and sea trials of a subsea holographic camera for large volume in-situ recording of marine organisms

    NASA Astrophysics Data System (ADS)

    Watson, John; Alexander, Stephen J.; Craig, Gary; Hendry, David C.; Hobson, Peter R.; Lampitt, R. S.; Marteau, J.-M.; Nareid, Helge; Nebrensky, J. J.; Player, Michael A.; Saw, Kevin; Tipping, Keith

    2002-06-01

    We describe the development, construction and sea testing of An underwater holographic camera (HoloCam) for in situ recording of marine organisms and particles in large volumes of sea water. HoloCam comprises a laser, power supply, holographic recording optics, and plate holders, a water- tight housing and a support frame. Added to this are control electronics such that the entire camera is remotely operable and controllable from ship or dock-side. Uniquely the camera can simultaneously record both in-line and off-axis holograms using a pulsed frequency double Nd:YAG laser. In- line holography is capable of producing images of organisms with a resolution of better than 10 micrometers . Off-axis holograms of aquatic systems of up to 50,000 cm3 volume, have been recorded. Following initial laboratory testing, the holo-camera was evaluated in an observation tank and ultimately was tested in Loch Etive, Scotland. In-line and off-axis holograms were recorded to a depth of 100 m. We will present result on the ste dives and evaluation of the camera performance.

  16. A 5 kA pulsed power supply for inductive and plasma loads in large volume plasma device.

    PubMed

    Srivastava, P K; Singh, S K; Sanyasi, A K; Awasthi, L M; Mattoo, S K

    2016-07-01

    This paper describes 5 kA, 12 ms pulsed power supply for inductive load of Electron Energy Filter (EEF) in large volume plasma device. The power supply is based upon the principle of rapid sourcing of energy from the capacitor bank (2.8 F/200 V) by using a static switch, comprising of ten Insulated Gate Bipolar Transistors (IGBTs). A suitable mechanism is developed to ensure equal sharing of current and uniform power distribution during the operation of these IGBTs. Safe commutation of power to the EEF is ensured by the proper optimization of its components and by the introduction of over voltage protection (>6 kV) using an indigenously designed snubber circuit. Various time sequences relevant to different actions of power supply, viz., pulse width control and repetition rate, are realized through optically isolated computer controlled interface.

  17. Determination of synthetic phenolic antioxidants in edible oils using microvial insert large volume injection gas-chromatography.

    PubMed

    Cacho, Juan Ignacio; Campillo, Natalia; Viñas, Pilar; Hernández-Córdoba, Manuel

    2016-06-01

    Three synthetic phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ), were determined in different edible vegetable oil samples. The analyses were carried out by gas chromatography-mass spectrometry (GC-MS) using microvial insert large volume injection (LVI). Several parameters affecting this sample introduction step, such as temperatures, times and gas flows, were optimised. Quantification was carried out by the matrix-matched calibration method using carvacrol as internal standard, providing quantification limits between 0.08 and 0.10 ng g(-1), depending on the compound. The three phenolic compounds were detected in several of the samples, BHT being the most frequently found. Recovery assays for oil samples spiked at two concentration levels, 2.5 and 10 ng g(-1), provided recoveries in the 86-115% range.

  18. Determination of multiclass pesticide residues in apple juice by gas chromatography-mass spectrometry with large-volume injection.

    PubMed

    Wang, Jian-Hua; Zhang, Yi-Bing; Wang, Xiu-Lin

    2006-10-01

    This study presents two GC-MS SIM methods, in combination with large-volume injection programmed-temperature vaporization (LVI-PTV) injection, for the determination of 141 pesticide residues in apple juice. The sample was extracted with ACN, and coextractives were removed with primary/secondary amine sorbent. ACN extract (20 microL) was injected into a PTV injection port in solvent vent mode, and the pesticides were determined by GC-MS using retention time locking software. Deuterium-labeled pesticides (surrogate standards) were used for analytical quality control. In the validation experiments, pesticides recoveries were found to be 70-121% with RSDs of 4.6-21% (n = 6).

  19. Yardea Dacite -large-volume, high-temperature felsic volcanism from the Middle Proterozoic of South Australia

    SciTech Connect

    Creaser, R.A.; White, A.J.R. )

    1991-01-01

    The Yardea Dacite is a large-volume felsic volcanic unit from the Middle Proterozoic Gawler Range Volcanics of South Australia; it has been previously described as an ignimbrite. However, some samples contain no petrographic evidence for a pyroclastic origin, but have characteristics compatible with final crystallization from a nonfragmented magma. These samples may have erupted as lavas, but others are likely to be extremely densely welded ignimbrites, suggesting a compound nature for the unit. Geothermometry and phase equilibria indicate that the Yardea Dacite originated from a high-temperature ({approximately}1,000{degree}C) felsic magma with a low water content ({le}2%). The Yardea Dacite is not associated with a known caldera of the Valles type, and shares many characteristics of recently described Cenozoic felsic volcanic rocks from the western United States, interpreted as rheoignimbrites or as unusually extensive lavas.

  20. A 5 kA pulsed power supply for inductive and plasma loads in large volume plasma device

    NASA Astrophysics Data System (ADS)

    Srivastava, P. K.; Singh, S. K.; Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.

    2016-07-01

    This paper describes 5 kA, 12 ms pulsed power supply for inductive load of Electron Energy Filter (EEF) in large volume plasma device. The power supply is based upon the principle of rapid sourcing of energy from the capacitor bank (2.8 F/200 V) by using a static switch, comprising of ten Insulated Gate Bipolar Transistors (IGBTs). A suitable mechanism is developed to ensure equal sharing of current and uniform power distribution during the operation of these IGBTs. Safe commutation of power to the EEF is ensured by the proper optimization of its components and by the introduction of over voltage protection (>6 kV) using an indigenously designed snubber circuit. Various time sequences relevant to different actions of power supply, viz., pulse width control and repetition rate, are realized through optically isolated computer controlled interface.

  1. Multiresidue determination of pesticides in agricultural products by gas chromatography/mass spectrometry with large volume injection.

    PubMed

    Saito, Yukio; Kodama, Shuji; Matsunaga, Akinobu; Yamamoto, Atsushi

    2004-01-01

    A method is described for the rapid determination of pesticide residues in agricultural products. Pesticides were extracted from samples with acetonitrile. To remove pigments and fatty acids, an aliquot of the extract was cleaned up by a minicolumn that was packed both with graphitized carbon black and primary secondary amine. Analysis was performed by gas chromatography/ mass spectrometry with programmable temperature vaporizer-based large volume injection using a liner packed with phenylmethylsilicone chemically bonded silica. The method was evaluated for 114 pesticides by spiking into tomato, spinach, Japanese pear, grape, and brown rice at various concentrations of each pesticide (0.02-0.4 microg/g). The method, which gave good recovery (>60%) for 108 pesticides, is characterized by high cleanup efficiency and short cleanup time, and is useful as a rapid screening analysis.

  2. A 3D CZT hard x-ray polarimeter for a balloon-borne payload

    NASA Astrophysics Data System (ADS)

    Caroli, E.; Alvarez, J. M.; Auricchio, N.; Budtz-Jørgensen, C.; Curado da Silva, R. M.; Del Sordo, S.; Ferrando, P.; Laurent, P.; Limousin, O.; Galvèz, J. L.; Gloster, C. P.; Hernanz, M.; Isern, J.; Kuvvetli, I.; Maia, J. M.; Meuris, A.; Stephen, J. B.; Zappettini, A.

    2012-09-01

    Today it is widely recognised that a measurement of the polarization status of cosmic sources high energy emission is a key observational parameter to understand the active production mechanism and its geometry. Therefore new instrumentation operating in the hard X/soft γ rays energy range should be optimized also for this type of measurement. In this framework, we present the concept of a small high-performance spectrometer designed for polarimetry between 100 and 1000 keV suitable as a stratospheric balloon-borne payload dedicated to perform an accurate and reliable measurement of the polarization status of the Crab pulsar, i.e. the polarization level and direction. The detector with 3D spatial resolution is based on a CZT spectrometer in a highly segmented configuration designed to operate as a high performance scattering polarimeter. We discuss different configurations based on recent development results and possible improvements currently under study. Furthermore we describe a possible baseline design of the payload, which can be also seen as a pathfinder for a high performance focal plane detector in new hard X and soft gamma ray focussing telescopes and/or advanced Compton instruments. Finally we present preliminary data from Montecarlo undergoing studies to determine the best trade-off between polarimetric performance and detector design complexity.

  3. Development of a 3D CZT detector prototype for Laue Lens telescope

    NASA Astrophysics Data System (ADS)

    Caroli, Ezio; Auricchio, Natalia; Del Sordo, Stefano; Abbene, Leonardo; Budtz-Jørgensen, Carl; Casini, Fabio; Curado da Silva, Rui M.; Kuvvetlli, Irfan; Milano, Luciano; Natalucci, Lorenzo; Quadrini, Egidio M.; Stephen, John B.; Ubertini, Pietro; Zanichelli, Massimiliano; Zappettini, Andrea

    2010-07-01

    We report on the development of a 3D position sensitive prototype suitable as focal plane detector for Laue lens telescope. The basic sensitive unit is a drift strip detector based on a CZT crystal, (~19×8 mm2 area, 2.4 mm thick), irradiated transversally to the electric field direction. The anode side is segmented in 64 strips, that divide the crystal in 8 independent sensor (pixel), each composed by one collecting strip and 7 (one in common) adjacent drift strips. The drift strips are biased by a voltage divider, whereas the anode strips are held at ground. Furthermore, the cathode is divided in 4 horizontal strips for the reconstruction of the third interaction position coordinate. The 3D prototype will be made by packing 8 linear modules, each composed by one basic sensitive unit, bonded on a ceramic layer. The linear modules readout is provided by a custom front end electronics implementing a set of three RENA-3 for a total of 128 channels. The front-end electronics and the operating logics (in particular coincidence logics for polarisation measurements) are handled by a versatile and modular multi-parametric back end electronics developed using FPGA technology.

  4. Changing the metabolic profile by large-volume liposuction: a clinical study conducted with 123 obese women.

    PubMed

    D'Andrea, Francesco; Grella, Roberto; Rizzo, Maria Rosaria; Grella, Elisa; Grella, Rodolfo; Nicoletti, Gianfranco; Barbieri, Michelangela; Paolisso, Giuseppe

    2005-01-01

    Adipose tissue is a metabolically active tissue. The hypertrophic fat cells of obese patients produce increased quantities of leptin and tumor necrosis factor-alpha (TNF-alpha) and are less sensitive to insulin. This study aimed to determine whether aspirating large amounts of these subcutaneous fat cells by large-volume liposuction (LVL), could change the metabolic profile in 123 obese women. All the patients had a main central body fat distribution (waist-hip ratio, 0.91+/-0.01) and a body mass index of 32.8 +/- 0.8 kg/m). They were studied for 90 days after LVL to determine their changes in insulin sensitivity, resting metabolic rate, serum adipocytokines, and inflammatory marker levels. During 3 months of follow-up evaluation, LVL resulted in a significantly improved insulin sensitivity, resting metabolic rate, serum adipocytokines, and inflammatory marker levels. Such parameters correlate with a decrease in fat mass and waist-hip ratio. Interestingly, no significant changes were seen between the first (21 days) and second (90 days) metabolic determinations after LVL. However, these findings, confirm other preliminary data published previously, and could change the actual role of LVL in the multidisciplinary treatment of obesity.

  5. Large Magnetoresistance and Volume Expansion Associated with Valence Transition in Eu(Rh1-xIrx)2Si2

    NASA Astrophysics Data System (ADS)

    Mitsuda, Akihiro; Fujimoto, Takumi; Kishaba, Eigo; Hamano, Suguru; Kondo, Akihiro; Kindo, Koichi; Wada, Hirofumi

    2016-12-01

    We report lattice parameters as a function of temperature, magnetization curves, and magnetoresistance of polycrystalline samples of Eu(Rh1-xIrx)2Si2. The lattice parameters a and c for x = 0.3, 0.4, and 0.5 jump at around the valence transition temperature Tv. For these samples, the high-temperature (larger a, c) and low-temperature (smaller a, c) phases, the volume fraction of which changes with temperature, coexist at around Tv, which means that the valence transition is of the first order. The magnetization curves of x = 0.3, 0.4, and 0.5 at T = 4.2 K exhibit a metamagnetic transition with a large hysteresis, implying a first-order field-induced valence transition. The transition field Bv is proportional to Tv, Bv = αTv with α = 0.36 T/K. For x = 0.3, a large negative magnetoresistance associated with the field-induced valence transition is observed. The origin of the negative magnetoresistance is discussed.

  6. a Method to Achieve Large Volume, High Accuracy Photogrammetric Measurements Through the Use of AN Actively Deformable Sensor Mounting Platform

    NASA Astrophysics Data System (ADS)

    Sargeant, B.; Robson, S.; Szigeti, E.; Richardson, P.; El-Nounu, A.; Rafla, M.

    2016-06-01

    When using any optical measurement system one important factor to consider is the placement of the sensors in relation to the workpiece being measured. When making decisions on sensor placement compromises are necessary in selecting the best placement based on the shape and size of the object of interest and the desired resolution and accuracy. One such compromise is in the distance the sensors are placed from the measurement surface, where a smaller distance gives a higher spatial resolution and local accuracy and a greater distance reduces the number of measurements necessary to cover a large area reducing the build-up of errors between measurements and increasing global accuracy. This paper proposes a photogrammetric approach whereby a number of sensors on a continuously flexible mobile platform are used to obtain local measurements while the position of the sensors is determined by a 6DoF tracking solution and the results combined to give a single set of measurement data within a continuous global coordinate system. The ability of this approach to achieve both high accuracy measurement and give results over a large volume is then tested and areas of weakness to be improved upon are identified.

  7. Large-volume leukapheresis for peripheral blood progenitor cell collection in low body weight pediatric patients: a single center experience.

    PubMed

    Cecyn, Karin Zattar; Seber, Adriana; Ginani, Valéria Cortez; Gonçalves, Alexandra Vieira; Caram, Eliana Maria; Oguro, Tsutomu; Oliveira, Olga Maria Wanderley; Carvalho, Maria Mercês; Bordin, José Orlando

    2005-06-01

    Peripheral blood progenitor cells (PBPC) have became the preferred source of stem cells for autologous transplantation because of easier accessibility, rapid engraftment, and lower tumor cell contamination. In pediatric patients is very important to optimize peripheral blood stem cells (PBSC) harvesting to obtain a sufficient number of cells with a reduced number of leukapheresis. In this study we prospectively analyzed data on 43 large volume leukapheresis (LVL) from 20 consecutive low body weight pediatric patients with various malignancies. Patients' mean body weight was 16.6 kg (range, 8.9-32.0 kg), and the median age was 4 years (range, 1-10 y ears). Instead of saline, it was used irradiated and leukoreduced red blood cell (RBC) units to prime the machine in 15 patients weighting 25 kg or less. The median number of LVL was 2 (range, 1-4) and a mean of 5.2 patient's blood volume was processed per session lasting 165 min (range, 118-239). The mean number of CD34+ cells, one day before leukapheresis was 49 mm(-3) (range, 9-219). The PBPC collection yielded 24.7 x 10(8) total nucleated cells/kg (range, 6.2-74.0), 10.7 x 10(6) kg(-1) CD34+ cells (range, 3.6-53.7); 49.8 x 10(4) CFU-GM/kg (range, 6.4-198.1), and 65.6 x 10(4) BFU-E/kg (range, 7.6-198.1). The platelet count decreased significantly after each procedure 39.8 +/- 9.1 x 10(9) mm(-3) (range, 18.000-76.000) (p < 0.001). In conclusion, our data show that LVL for collection of PBPC in low weight pediatric patients is a safe and efficient procedure, but it may expose the patient to the risk of thrombocytopenia.

  8. Large Cohort Dose-Volume Response Analysis of Parotid Gland Function After Radiotherapy: Intensity-Modulated Versus Conventional Radiotherapy

    SciTech Connect

    Dijkema, Tim Terhaard, Chris H.J.; Roesink, Judith M.; Braam, Petra M.; Gils, Carla H. van; Moerland, Marinus A.; Raaijmakers, Cornelis P.J.

    2008-11-15

    Purpose: To compare parotid gland dose-volume response relationships in a large cohort of patients treated with intensity-modulated (IMRT) and conventional radiotherapy (CRT). Methods and materials: A total of 221 patients (64 treated with IMRT, 157 with CRT) with various head-and-neck malignancies were prospectively evaluated. The distribution of tumor subsites in both groups was unbalanced. Stimulated parotid flow rates were measured before and 6 weeks, 6 months, and 1 year after radiotherapy. Parotid gland dose-volume histograms were derived from computed tomography-based treatment planning. The normal tissue complication probability (NTCP) model proposed by Lyman was fit to the data. A complication was defined as stimulated parotid flow ratio <25% of the pretreatment flow rate. The relative risk of complications was determined for IMRT vs. CRT and adjusted for the mean parotid gland dose using Poisson regression modeling. Results: One year after radiotherapy, NTCP curves for IMRT and CRT were comparable with a TD{sub 50} (uniform dose leading to a 50% complication probability) of 38 and 40 Gy, respectively. Until 6 months after RT, corrected for mean dose, different complication probabilities existed for IMRT vs. CRT. The relative risk of a complication for IMRT vs. CRT after 6 weeks was 1.42 (95% CI 1.21-1.67), after 6 months 1.41 (95% CI; 1.12-1.77), and at 1 year 1.21 (95% CI 0.87-1.68), after correcting for mean dose. Conclusions: One year after radiotherapy, no difference existed in the mean dose-based NTCP curves for IMRT and CRT. Early after radiotherapy (up to 6 months) mean dose based (Lyman) models failed to fully describe the effects of radiotherapy on the parotid glands.

  9. Large volume inside the cage leading incomplete interbody bone fusion and residual back pain after posterior lumbar interbody fusion.

    PubMed

    Takeuchi, Mikinobu; Kamiya, Mitsuhiro; Wakao, Norimitsu; Hirasawa, Atsuhiko; Kawanami, Katsuhisa; Osuka, Koji; Takayasu, Masakazu

    2015-07-01

    The purpose of this study is to compare intervertebral bone fusion and clinical outcomes in L4-5 posterior lumbar interbody fusion (PLIF) using the same posterior instrumentation with four combinations of one of three types of interbody cage with one of two bone grafts, iliac and local or only local. In 67 patients who underwent L4-5 PLIF, 19 patients had the Brantigan cage and iliac and local bone graft, 18 with the TELAMON C cage and iliac and local bone graft, 16 with the TELAMON C cage and local bone graft (TL), and 14 with the OIC PEEK cage and local bone graft. Clinical assessments were based on Japanese Orthopaedic Association (JOA) scores and on the visual analogue scale (VAS). The bone fusion assessments were based on radiography and CT scans according to the Brantigan, Steffee, and Fraser criteria. More than 2 years after surgery, these assessments were made. In the results, the fusion outcome for the group receiving TL was significantly less than those for the other three groups. In TL, multivariate logistic regression analysis showed that the inside volume of the cage of ≥2.0 mL was the only significant factor for incomplete fusion. Moreover, the VAS (low back pain) score was significantly higher for TL than for the other three groups. In conclusions, we believe that the large volume inside the cage (≥2.0 mL) with local bone graft may lead incomplete interbody bone fusion and residual postsurgical low back pain after PLIF.

  10. Low resistance, large dimension entrance to the inner cavity of BK channels determined by changing side-chain volume

    PubMed Central

    Niu, Xiaowei

    2011-01-01

    Large-conductance Ca2+- and voltage-activated K+ (BK) channels have the largest conductance (250–300 pS) of all K+-selective channels. Yet, the contributions of the various parts of the ion conduction pathway to the conductance are not known. Here, we examine the contribution of the entrance to the inner cavity to the large conductance. Residues at E321/E324 on each of the four α subunits encircle the entrance to the inner cavity. To determine if 321/324 is accessible from the inner conduction pathway, we measured single-channel current amplitudes before and after exposure and wash of thiol reagents to the intracellular side of E321C and E324C channels. MPA− increased currents and MTSET+ decreased currents, with no difference between positions 321 and 324, indicating that side chains at 321/324 are accessible from the inner conduction pathway and have equivalent effects on conductance. For neutral amino acids, decreasing the size of the entrance to the inner cavity by substituting large side-chain amino acids at 321/324 decreased outward single-channel conductance, whereas increasing the size of the entrance with smaller side-chain substitutions had little effect. Reductions in outward conductance were negated by high [K+]i. Substitutions had little effect on inward conductance. Fitting plots of conductance versus side-chain volume with a model consisting of one variable and one fixed resistor in series indicated an effective diameter and length of the entrance to the inner cavity for wild-type channels of 17.7 and 5.6 Å, respectively, with the resistance of the entrance ∼7% of the total resistance of the conduction pathway. The estimated dimensions are consistent with the structure of MthK, an archaeal homologue to BK channels. Our observations suggest that BK channels have a low resistance, large entrance to the inner cavity, with the entrance being as large as necessary to not limit current, but not much larger. PMID:21576375

  11. Application of ultradisperse magnetic adsorbents for removal of small concentrations of pollutants from large volumes of water

    NASA Astrophysics Data System (ADS)

    Nechitailo, Galina S.; Kuznetsov, Anatoli; Kuznetsov, Oleg

    2016-07-01

    Pollution of natural bodies of water (rivers, lakes, ground water, etc) is unfortunately very common, both from natural sources like volcanic activity; and, even more importantly, from human activity, including disposal of industrial and municipal waste, mining, etc. Many toxic substances are harmful for humans and other organisms even in very low concentrations (e.g., less than 1 µg/L of cadmium is harmful, for Hg it is 0.5 µg/L, for phenol - 1 µg/L), and can remain in water for decades or longer. Cleaning large volumes of water even from low concentrations of pollutants is a challenging technological task and is very expensive. We propose to use suspension of ultradisperse magnetic adsorbents, for example, nanostructured ferro-carbon particles, produced by plasmachemical technique, for removing small concentrations of pollutants from large volumes of water. The suspension is introduced into the water. Due to their small sizes and densities similar to water (we measured the density of FC-4 ferro-carbon to be about 1 g/cm3; presumably due to porosity) the particles do not sediment for a long time (hours, days or longer), move due to Brownian motion and adsorb a variety of substances from the water. The particle surface can be modified to provide selectivity of the adsorption. Sorption capacities of ferro-carbon adsorbents is in dozens of percent. Therefore, to collect 1 kg of a pollutant, 2 to 20 kg of the adsorbents is required. Then the particles with the adsorbed contaminant can be collected (e.g., downstream of the river) using a variety of magnetic traps. The traps can consist of ferromagnetic wires and permanent magnets, a variety of simple and inexpensive designs are available. As a model system, the kinetics of adsorption of a highly diluted (0.002 mg/ml) aqueous solution of a low molecular weight compound (toluidine blue) by a small concentration of a ferro-carbon powder (FC-4) was studied by spectrophotometry. Before each measurement, the particles

  12. Design and optimization of a new-generation CZT-based positron emission tomography system (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Abbaszadeh, Shiva; Levin, Craig

    2016-10-01

    The goal of this work is to develop and explore a novel small animal PET system that will advance our ability to detect, visualize, and quantify low concentrations of molecular probes. Key technologies of this work are: (1) A superior performance cadmium zinc telluride (CZT) detector technology that uses solid-state semiconductor detectors, instead of scintillation crystals, to achieve ultra-high (≤ 1 mm3) resolution, 3-dimensional (3-D) event positioning and excellent energy resolution. (2) A novel edge-on arrangement of these semiconductor crystals in a four-sided panel geometry that facilitates an order of magnitude greater photon detection efficiency. The 3-D position sensitive dual-CZT detector module and readout electronics developed in our lab was scaled up to complete a significant portion of the final PET system. This sub-system was configured as two opposing detection panels containing a total of twelve 40 mm × 40 mm 5 mm monolithic CZT crystals for proof of concept. System-level characterization studies, including optimizing the trigger threshold of each channel's comparators, were performed. 68Ge and 137Cs radioactive isotopes were used to characterize the energy resolution of all 468 anode channels in the sub-system. The mean measured global 511 keV photopeak energy resolution over all anodes was found to be 7.35±1.75% FWHM after correction for photon interaction depth-dependent signal variation. The measured global time resolution was 24 ns FWHM after precise time caibration, and the intrinsic spatial resolution was 0.76 mm FWHM.

  13. New Technology CZT Detectors for High-Energy Flare Spectroscopy: The Room Temperature Semiconductor Spectrometer for JAWSAT

    NASA Technical Reports Server (NTRS)

    Vestrand, W. Thomas

    1999-01-01

    The goal of our Room Temperature Semiconductor Spectrometer (RTeSS) project is to develop a small high-energy solar flare spectrometer employing semiconductor detectors that do not require significant cooling when used as high-energy solar flare spectrometers. Specifically, the goal is to test Cadmium Zinc Telluride (CZT) detectors with coplanar grid electrodes as x-ray and gamma-ray spectrometers and to design an experiment that can be flown as a "piggy-back" payload on a satellite mission during the next solar maximum.

  14. The Use of Cryogenically Cooled 5A Molecular Sieves for Large Volume Reduction of Tritiated Hydrogen Gas

    SciTech Connect

    Antoniazzi, A.B.; Bartoszek, F.E.; Sherlock, A.M.

    2006-07-01

    A commercial hydrogen isotope separation system based on gas chromatography (AGC-ISS) has been built. The system operates in two modes: stripping and volume reduction. The purpose of the stripping mode is to reduce a large volume of tritiated hydrogen gas to a small volume of tritium rich hydrogen gas. The results here illustrate the effectiveness of the AGC-ISS in the stripping and volume reduction phases. Column readiness for hydrogen isotope separation is confirmed by room temperature air separation tests. Production runs were initially carried out using natural levels of deuterium (110-160 ppm) in high purity hydrogen. After completion of the deuterium/hydrogen runs the system began operations with tritiated hydrogen. The paper presents details of the AGC-ISS design and results of tritium tests. The heart of the AGC-ISS consists of two packed columns (9 m long, 3.8 cm OD) containing 5A molecular sieve material of 40/60 mesh size. Each column has 5 individually controlled heaters along the length of the column and is coiled around an inverted inner dewar. The coiled column and inner dewar are both contained within an outer dewar. In this arrangement liquid nitrogen, used to cryogenically cool the columns, flows into and out off the annular space defined by the two dewars, allowing for alternate heating and cooling cycles. Tritiated hydrogen feed is injected in batch quantities. The batch size is variable with the maximum quantity restricted by the tritium concentration in the exhausted hydrogen. The stripping operations can be carried out in full automated mode or in full manual mode. The average cycle time between injections is about 75 minutes. To date, the maximum throughput achieved is 10.5 m{sup 3}/day. A total of 37.8 m{sup 3} of tritiated hydrogen has been processed during commissioning. The system has demonstrated that venting of >99.95% of the feed gas is possible while retaining 99.98% of the tritium. At a maximum tritium concentration of {approx}7 GBq

  15. Detection of s-triazine pesticides in natural waters by modified large-volume direct injection HPLC.

    PubMed

    Beale, David J; Kaserzon, Sarit L; Porter, Nichola A; Roddick, Felicity A; Carpenter, Peter D

    2010-07-15

    There is a need for simple and inexpensive methods to quantify potentially harmful persistent pesticides often found in our water-ways and water distribution systems. This paper presents a simple, relatively inexpensive method for the detection of a group of commonly used pesticides (atrazine, simazine and hexazinone) in natural waters using large-volume direct injection high performance liquid chromatography (HPLC) utilizing a monolithic column and a single wavelength ultraviolet-visible light (UV-vis) detector. The best results for this system were obtained with a mobile phase made up of acetonitrile and water in a 30:70 ratio, a flow rate of 2.0 mL min(-1), and a detector wavelength of 230 nm. Using this method, we achieved retention times of less than three minutes, and detection limits of 5.7 microg L(-1) for atrazine, 4.7 microg L(-1) for simazine and 4.0 microg L(-1) for hexazinone. The performance of this method was validated with an inter-laboratory trial against a National Association of Testing Authorities (NATA) accredited liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method commonly used in commercial laboratories.

  16. Determination of organophosphorus pesticides by gas chromatography with mass spectrometry using a large-volume injection technique after magnetic extraction.

    PubMed

    Nedaei, Maryam; Salehpour, Ali-Reza; Mozaffari, Shahla; Yousefi, Seyedeh Mahboobeh; Yousefi, Seyed Reza

    2014-09-01

    A fast and efficient method was developed for the extraction and determination of organophosphorus pesticides in water samples. Organophosphorus pesticides were extracted by solid-phase extraction using magnetic multi-walled carbon nanotubes and determined by gas chromatography with ion-trap mass spectrometry. Parameters affecting the extraction were investigated. Under optimum conditions of the method, 10 mg magnetic multi-walled carbon nanotubes were added into 10 mL sample. After 2 min, adsorbent particles settled at the bottom of test tube with a magnet. After removing aqueous supernatant, the analytes were desorbed with acetonitrile. Then, 70 μL of acetonitrile phase was injected into the gas chromatography and mass spectrometry system that had an ion-trap analyzer. To achieve high sensitivity, the large-volume-injection technique was used with a programmed temperature vaporization inlet, and the ion-trap mass spectrometer was operated in single ion storage mode. Under the best conditions, the enrichment factors and extraction recoveries were in the range of 113-124 and 74-103%, respectively. The limits of detection were between 3 and 15 ng/L, and the relative standard deviations were < 10%. This method was successfully used for the determination of organophosphorus pesticides in dam water, lagoon water, and river water samples with good reproducibility and recovery.

  17. A Large Volume Double Channel 1H-X RF Probe for Hyperpolarized Magnetic Resonance at 0.0475 Tesla

    PubMed Central

    Coffey, Aaron M.; Shchepin, Roman V.; Wilkens, Ken; Waddell, Kevin W.; Chekmenev, Eduard Y.

    2012-01-01

    In this work we describe a large volume 340 mL 1H-X magnetic resonance (MR) probe for studies of hyperpolarized compounds at 0.0475 T. 1H/13C and 1H/15N probe configurations are demonstrated with the potential for extension to 1H/129Xe. The primary applications of this probe are preparation and quality assurance of 13C and 15N hyperpolarized contrast agents using PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) and other parahydrogen-based methods of hyperpolarization. The probe is efficient and permits 62 μs 13C excitation pulses at 5.3 Watts, making it suitable for portable operation. The sensitivity and detection limits of this probe, tuned to 13C, are compared with a commercial radio frequency (RF) coil operating at 4.7 T. We demonstrate that low field MR of hyperpolarized contrast agents could be as sensitive as conventional high field detection and outline potential improvements and optimization of the probe design for preclinical in vivo MRI. PASADENA application of this low-power probe is exemplified with 13C hyperpolarized 2-hydroxyethyl propionate-1-13C,2,3,3-d3. PMID:22706029

  18. Novel experimental design for high pressure-high temperature electrical resistance measurements in a "Paris-Edinburgh" large volume press.

    PubMed

    Matityahu, Shlomi; Emuna, Moran; Yahel, Eyal; Makov, Guy; Greenberg, Yaron

    2015-04-01

    We present a novel experimental design for high sensitivity measurements of the electrical resistance of samples at high pressures (0-6 GPa) and high temperatures (300-1000 K) in a "Paris-Edinburgh" type large volume press. Uniquely, the electrical measurements are carried out directly on a small sample, thus greatly increasing the sensitivity of the measurement. The sensitivity to even minor changes in electrical resistance can be used to clearly identify phase transitions in material samples. Electrical resistance measurements are relatively simple and rapid to execute and the efficacy of the present experimental design is demonstrated by measuring the electrical resistance of Pb, Sn, and Bi across a wide domain of temperature-pressure phase space and employing it to identify the loci of phase transitions. Based on these results, the phase diagrams of these elements are reconstructed to high accuracy and found to be in excellent agreement with previous studies. In particular, by mapping the locations of several well-studied reference points in the phase diagram of Sn and Bi, it is demonstrated that a standard calibration exists for the temperature and pressure, thus eliminating the need for direct or indirect temperature and pressure measurements. The present technique will allow simple and accurate mapping of phase diagrams under extreme conditions and may be of particular importance in advancing studies of liquid state anomalies.

  19. Novel experimental design for high pressure-high temperature electrical resistance measurements in a "Paris-Edinburgh" large volume press

    NASA Astrophysics Data System (ADS)

    Matityahu, Shlomi; Emuna, Moran; Yahel, Eyal; Makov, Guy; Greenberg, Yaron

    2015-04-01

    We present a novel experimental design for high sensitivity measurements of the electrical resistance of samples at high pressures (0-6 GPa) and high temperatures (300-1000 K) in a "Paris-Edinburgh" type large volume press. Uniquely, the electrical measurements are carried out directly on a small sample, thus greatly increasing the sensitivity of the measurement. The sensitivity to even minor changes in electrical resistance can be used to clearly identify phase transitions in material samples. Electrical resistance measurements are relatively simple and rapid to execute and the efficacy of the present experimental design is demonstrated by measuring the electrical resistance of Pb, Sn, and Bi across a wide domain of temperature-pressure phase space and employing it to identify the loci of phase transitions. Based on these results, the phase diagrams of these elements are reconstructed to high accuracy and found to be in excellent agreement with previous studies. In particular, by mapping the locations of several well-studied reference points in the phase diagram of Sn and Bi, it is demonstrated that a standard calibration exists for the temperature and pressure, thus eliminating the need for direct or indirect temperature and pressure measurements. The present technique will allow simple and accurate mapping of phase diagrams under extreme conditions and may be of particular importance in advancing studies of liquid state anomalies.

  20. Quantitative Determination of Fluorinated Alkyl Substances by Large-Volume-Injection LC/MS/MS—Characterization of Municipal Wastewaters

    PubMed Central

    Schultz, Melissa M.; Barofsky, Douglas F.; Field, Jennifer A.

    2008-01-01

    A quantitative method was developed for the determination of fluorinated alkyl substances in municipal wastewater influents and effluents. The method consisted of centrifugation followed by large-volume injection (500 μL) of the supernatant onto a liquid chromatograph with a reverse-phase column and detection by electrospray ionization, and tandem mass spectrometry (LC/MS/MS). The fluorinated analytes studied include perfluoroalkyl sulfonates, fluorotelomer sulfonates, perfluorocarboxylates, and select fluorinated alkyl sulfonamides. Recoveries of the fluorinated analytes from wastewater treatment plant (WWTP) raw influents and final effluent ranged from 77% – 96% and 80% – 99%, respectively. The lower limit of quantitation ranged from 0.5 to 3.0 ng/L depending on the analyte. The method was applied to flow-proportional composites of raw influent and final effluent collected over a 24 hr period from ten WWTPs nationwide. Fluorinated alkyl substances were observed in wastewater at all treatment plants and each plant exhibited unique distributions of fluorinated alkyl substances despite similarities in treatment processes. In nine out of the ten plants sampled, at least one class of fluorinated alkyl substances exhibited increased concentrations in the effluent as compared to the influent concentrations. In some instances, decreases in certain fluorinated analyte concentrations were observed and attributed to sorption to sludge. PMID:16433363

  1. Colorimetric paper-based detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes of agricultural water.

    PubMed

    Bisha, Bledar; Adkins, Jaclyn A; Jokerst, Jana C; Chandler, Jeffrey C; Pérez-Méndez, Alma; Coleman, Shannon M; Sbodio, Adrian O; Suslow, Trevor V; Danyluk, Michelle D; Henry, Charles S; Goodridge, Lawrence D

    2014-06-09

    This protocol describes rapid colorimetric detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes (10 L) of agricultural waters. Here, water is filtered through sterile Modified Moore Swabs (MMS), which consist of a simple gauze filter enclosed in a plastic cartridge, to concentrate bacteria. Following filtration, non-selective or selective enrichments for the target bacteria are performed in the MMS. For colorimetric detection of the target bacteria, the enrichments are then assayed using paper-based analytical devices (µPADs) embedded with bacteria-indicative substrates. Each substrate reacts with target-indicative bacterial enzymes, generating colored products that can be detected visually (qualitative detection) on the µPAD. Alternatively, digital images of the reacted µPADs can be generated with common scanning or photographic devices and analyzed using ImageJ software, allowing for more objective and standardized interpretation of results. Although the biochemical screening procedures are designed to identify the aforementioned bacterial pathogens, in some cases enzymes produced by background microbiota or the degradation of the colorimetric substrates may produce a false positive. Therefore, confirmation using a more discriminatory diagnostic is needed. Nonetheless, this bacterial concentration and detection platform is inexpensive, sensitive (0.1 CFU/ml detection limit), easy to perform, and rapid (concentration, enrichment, and detection are performed within approximately 24 hr), justifying its use as an initial screening method for the microbiological quality of agricultural water.

  2. What Would Be the Effect of Referral to High-Volume Hospitals in a Largely Rural State?

    ERIC Educational Resources Information Center

    Ward, Marcia M.; Jaana, Mirou; Wakefield, Douglas S.; Ohsfeldt, Robert L.; Schneider, John E.; Miller, Thomas; Lei, Yang

    2004-01-01

    Volume of certain surgical procedures has been linked to patient outcomes. The Leapfrog Group and others have recommended evidence-based referral using specific volume thresholds for nonemergent cases. The literature is limited on the effect of such referral on hospitals, especially in rural areas. To examine the impact of evidence-based referral…

  3. (135)Xe measurements with a two-element CZT-based radioxenon detector for nuclear explosion monitoring.

    PubMed

    Ranjbar, Lily; Farsoni, Abi T; Becker, Eric M

    2017-04-01

    Measurement of elevated concentrations of xenon radioisotopes ((131m)Xe, (133m)Xe, (133)Xe and (135)Xe) in the atmosphere has been shown to be a very powerful method for verifying whether or not a detected explosion is nuclear in nature. These isotopes are among the few with enough mobility and with half-lives long enough to make their detection at long distances realistic. Existing radioxenon detection systems used by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) suffer from problems such as complexity, need for high maintenance and memory effect. To study the response of CdZnTe (CZT) detectors to xenon radioisotopes and investigate whether it is capable of mitigating the aforementioned issues with the current radioxenon detection systems, a prototype detector utilizing two coplanar CZT detectors was built and tested at Oregon State University. The detection system measures xenon radioisotopes through beta-gamma coincidence technique by detecting coincidence events between the two detectors. In this paper, we introduce the detector design and report our measurement results with radioactive lab sources and (135)Xe produced in the OSU TRIGA reactor. Minimum Detectable Concentration (MDC) for (135)Xe was calculated to be 1.47 ± 0.05 mBq/m(3).

  4. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

    NASA Astrophysics Data System (ADS)

    Cai, Liang; Meng, Ling-Jian

    2013-02-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X-Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2-5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper.

  5. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system.

    PubMed

    Cai, Liang; Meng, Ling-Jian

    2013-02-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X-Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2-5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper.

  6. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

    PubMed Central

    Cai, Liang; Meng, Ling-Jian

    2013-01-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X–Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2–5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper. PMID:24371365

  7. Flowing and growing: a microanalytical and isotopic investigation of a large volume rhyolite lava flow at Yellowstone

    NASA Astrophysics Data System (ADS)

    Severin, Z.; Bindeman, I. N.; Lackey, J.

    2013-12-01

    Why large-volume rhyolitic magmas with identical properties and volatile budgets erupt as both pyroclastic rocks forming calderas, and quiet lava flows, has remained a long standing question at Yellowstone and volcanic centers worldwide. We have investigated the youngest lava flow of Yellowstone - the Central Plateau member (0.2-0.07 Ma) in attempt to better understand the following aspects of a large-volume (≤54 km^3) lava flow: 1) how long it takes to erupt; 2) how chemically and isotopically homogenous it is; and 3) how syneruptive cooling affects isotopic and chemical composition. We also analyze the homogeneity of the 112 ka, 37 km^3, low-δ^18O Summit Lake lava flow, which formed by remelting of hydrothermally altered and buried materials. On the surface twenty samples were collected along a southwest-northeast transect from the flow vent to the lava flow edge. We examined these samples petrographically and chemically, employing whole rock geochemistry, the titanium content of quartz phenocrysts to calculate relative temperature of growth using the Ti-in-quartz thermometer (TitaniQ), and the δ^18O of volcanic glass. The Ti content of quartz is useful for inferring the temperature, pressure, and/or chemical conditions of quartz crystallization. We also used cathodoluminescence imaging (CL) on a scanning electron microscopy (SEM) to distinguish quartz cores from overgrowths. Values of δ^18O are relatively homogeneous across the flow (4.60 × 0.59‰, n=20), showing no systematic variation with distance from the vent. Whole-rock major element composition is also homogenous across the flow (SiO2 = 75.08-77.03 wt.%). However, precise grid-counting reveals a general increase in the percent of phenocrysts (4.4-7.3%) and also the ratio of quartz to feldspar (40:60). CL shows that all quartz phenocrysts display a renewed growth as a dark ~200 μm-thick rims upon by bright cores. Among the quartz phenocrysts, Ti generally decreases from 139×39 ppm in bright cores

  8. Fast determination of 40 drugs in water using large volume direct injection liquid chromatography-tandem mass spectrometry.

    PubMed

    Boix, Clara; Ibáñez, María; Sancho, Juan V; Rambla, Javier; Aranda, José L; Ballester, Salomé; Hernández, Félix

    2015-01-01

    This work describes a rapid analytical method based on direct sample injection of water samples for the simultaneous identification/quantification of 40 emerging compounds, including pharmaceuticals and drugs of abuse. The water samples were analyzed by ultra-high-performance liquid chromatography coupled to hybrid triple quadrupole mass spectrometer (UHPLC-MS/MS QqQ). Taking profit of the increasing sensitivity of nowadays tandem mass spectrometers, direct sample injection of large volumes has been an attractive alternative to pre-concentration steps. In this work, the developed methodology has been validated at three concentration levels (10, 100 and 1000 ng/L) in 10 different water samples of different types (5 effluent wastewater and 5 surface water samples). The majority of compounds could be satisfactory validated at these concentrations, showing good recoveries and precision. With only few exceptions, the limits of quantification (LOQs), estimated from the sample chromatogram at lowest spiked level tested, were below 3 ng/L. The method was applied to the analysis of 10 effluent wastewater and 10 surface water samples. Venlafaxine was the compound most frequently detected (80%) in surface water, followed by acetaminophen (70%). Regarding effluent wastewater, valsartan and 4-acetyl aminoantipyrine were detected in 9 out of 10 samples analyzed. These two compounds together with 4-formyl aminoantipyrine and naproxen showed the highest concentrations (>2000 ng/L). In these cases, a dilution step was required for a correct quantification. As an additional evaluation of the method performance, the same water samples were analyzed in another laboratory by a second analytical methodology, based on on-line solid-phase-extraction coupled to LC-MS/MS (QqQ).

  9. Large volume sample stacking in capillary zone electrophoresis for the monitoring of the degradation products of metribuzin in environmental samples.

    PubMed

    Quesada-Molina, Carolina; García-Campaña, Ana M; Del Olmo-Iruela, Laura; Del Olmo, Monsalud

    2007-09-14

    A capillary zone electrophoresis (CZE) method with UV-vis detection has been developed for the simultaneous monitoring of the major degradation products of metribuzin, i.e. deaminometribuzin (DA), deaminodiketometribuzin (DADK) and diketometribuzin (DK). The dissociation acid constants have also been estimated by CE and no significant differences have been observed with the values obtained by applying other techniques. Optimum separation has been achieved in less than 9 min in 40 mM sodium tetraborate buffer, pH 9.5 by applying a voltage of 15kV at 25 degrees C and using p-aminobenzoic acid as internal standard. In order to increase sensitivity, large volume sample stacking (LVSS) with polarity switching has been applied as on-line pre-concentration methodology. Detection limits of 10, 10 and 20 ng/mL for DA, DADK and DK, respectively were obtained. The method has been applied to soil samples, after pressurized liquid extraction (PLE). Samples were extracted at high temperature (103 degrees C and 1500 psi) using methanol as extraction solvent and sodium sulphate as drying agent. This PLE procedure was followed by an off-line pre-concentration and sample clean-up procedure by solid-phase extraction (SPE) using a LiChrolut EN sorbent column. These last two procedures were also suitable for the direct treatment of groundwater samples before CE analysis. The combination of both off-line and on-line pre-concentration procedures provided a significant improvement in sensitivity. LVSS provided pre-concentration factors of 4, 36 and 28 for DK, DA and DADK, respectively and with SPE a pre-concentration of 500-fold for the case of water samples and of 2.5-fold in the case of soil samples was obtained. The method is suitable for the monitoring of these residues in environmental samples with high sensitivity, precision and satisfactory recoveries.

  10. Rain Characteristics and Large-Scale Environments of Precipitation Objects with Extreme Rain Volumes from TRMM Observations

    NASA Technical Reports Server (NTRS)

    Zhou, Yaping; Lau, William K M.; Liu, Chuntao

    2013-01-01

    This study adopts a "precipitation object" approach by using 14 years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Feature (PF) and National Centers for Environmental Prediction (NCEP) reanalysis data to study rainfall structure and environmental factors associated with extreme heavy rain events. Characteristics of instantaneous extreme volumetric PFs are examined and compared to those of intermediate and small systems. It is found that instantaneous PFs exhibit a much wider scale range compared to the daily gridded precipitation accumulation range. The top 1% of the rainiest PFs contribute over 55% of total rainfall and have 2 orders of rain volume magnitude greater than those of the median PFs. We find a threshold near the top 10% beyond which the PFs grow exponentially into larger, deeper, and colder rain systems. NCEP reanalyses show that midlevel relative humidity and total precipitable water increase steadily with increasingly larger PFs, along with a rapid increase of 500 hPa upward vertical velocity beyond the top 10%. This provides the necessary moisture convergence to amplify and sustain the extreme events. The rapid increase in vertical motion is associated with the release of convective available potential energy (CAPE) in mature systems, as is evident in the increase in CAPE of PFs up to 10% and the subsequent dropoff. The study illustrates distinct stages in the development of an extreme rainfall event including: (1) a systematic buildup in large-scale temperature and moisture, (2) a rapid change in rain structure, (3) explosive growth of the PF size, and (4) a release of CAPE before the demise of the event.

  11. Large volume leukapheresis is efficient and safe even in small children up to 15 kg body weight

    PubMed Central

    Bojanic, Ines; Mazic, Sanja; Rajic, Ljubica; Jakovljevic, Gordana; Stepan, Jasminka; Cepulic, Branka Golubic

    2017-01-01

    Background The collection of peripheral blood stem cells, although now a routine procedure, is still a challenge in low body weight children because of specific technical and clinical issues. For paediatric patients it is crucial to obtain an adequate number of CD34+ cells with the minimum number of procedures: this can be done using large volume leukapheresis (LVL). Materials and methods We analysed the efficacy and safety of 54 autologous LVL performed in 50 children (33 [66%] males and 17 [34%] females), median age 2 years (range, 1–5) and median body weight 12 kg (range, 6–15). The procedures were performed with a COBE Spectra previously primed with red blood cells; ACD-A solution and heparin were used as anticoagulants. Results The target CD34+ cell dose (≥5×10/kg body weight) were collected with one LVL in 46 (92%) patients, while four (8%) patients needed another procedure. All our LVL were well tolerated. Side effects were observed in five (9.2%) patients and one procedure had to be discontinued because of catheter-related haemorrhage. The platelet count decreased significantly (p<0.001) after each procedure but without bleeding or need for transfusion support. Discussion Our experience confirms that LVL is efficient and safe even in small children, if the procedure is adjusted considering the weight and age of child. The most important factors are good venous access, adequate preparation of the child’s electrolyte status, and surroundings in which the small child as well as parents feel comfortable, and can tolerate the procedure better. Although a median platelet loss of 50% can be expected, LVL is safe and reduces the overall number of procedures required. It can be recommended for peripheral blood stem cell collection even in small body weight children with malignant diseases, particularly those who mobilise low numbers of CD34+ cells. PMID:27136428

  12. Large wood recruitment processes and transported volumes in Swiss mountain streams during the extreme flood of August 2005

    NASA Astrophysics Data System (ADS)

    Steeb, Nicolas; Rickenmann, Dieter; Badoux, Alexandre; Rickli, Christian; Waldner, Peter

    2017-02-01

    The extreme flood event that occurred in August 2005 was the most costly (documented) natural hazard event in the history of Switzerland. The flood was accompanied by the mobilization of > 69,000 m3 of large wood (LW) throughout the affected area. As recognized afterward, wood played an important role in exacerbating the damages, mainly because of log jams at bridges and weirs. The present study aimed at assessing the risk posed by wood in various catchments by investigating the amount and spatial variability of recruited and transported LW. Data regarding LW quantities were obtained by field surveys, remote sensing techniques (LiDAR), and GIS analysis and was subsequently translated into a conceptual model of wood transport mass balance. Detailed wood budgets and transport diagrams were established for four study catchments of Swiss mountain streams, showing the spatial variability of LW recruitment and deposition. Despite some uncertainties with regard to parameter assumptions, the sum of reconstructed wood input and observed deposition volumes agree reasonably well. Mass wasting such as landslides and debris flows were the dominant recruitment processes in headwater streams. In contrast, LW recruitment from lateral bank erosion became significant in the lower part of mountain streams where the catchment reached a size of about 100 km2. According to our analysis, 88% of the reconstructed total wood input was fresh, i.e., coming from living trees that were recruited from adjacent areas during the event. This implies an average deadwood contribution of 12%, most of which was estimated to have been in-channel deadwood entrained during the flood event.

  13. Successful treatment of a LifeSite Hemodialysis Access System pocket infection with large-volume kanamycin solution irrigation.

    PubMed

    Ross, John R

    2003-07-01

    Bridge devices-dialysis catheters and subcutaneous access devices-play a critical role in increasing the placement of arteriovenous (AV) fistulas by providing hemodialysis vascular access while AV fistulas mature. The LifeSite Hemodialysis Access System (Vasca Inc, Tewskburg, MA), a fully implantable, subcutaneous dual valve access system, has been shown to have lower complication rates, higher blood flow rates, and better long-term device survival than conventional tunneled hemodialysis catheters, indicating it may better meet the requirements for optimally bridging to a fistula. This case study of a 48-year-old black man undergoing chronic hemodialysis for renal failure because of insulin-dependent diabetes describes a simple approach for resolving localized pocket infections associated with the LifeSite System by drip irrigation of the valves and tissue pockets with an antibiotic solution. Eight weeks after implantation of the LifeSite System, the patient exhibited symptoms of infection of the lateral LifeSite valve tissue pocket, which on culture was shown to be caused by Staphylococcus aureus. Flushing the LifeSite valve and tissue pocket with a large volume of kanamycin solution, in conjunction with intravenous vancomycin and routine irrigation of the valve with isopropyl alcohol, resolved the infection after 1 treatment. The LifeSite System successfully bridged the patient to a transposed basilic vein fistula created through a 2-stage surgical procedure. The LifeSite System provided uninterrupted access for hemodialysis over a period of 6 months while the fistula matured. The LifeSite System should allow surgeons to attempt fistula construction in more patients, including diabetics, access-challenged patients, and patients with small vessels, who may benefit from a nontraditional surgical approach toward fistula creation.

  14. Trace analysis of isothiazolinones in water samples by large-volume direct injection liquid chromatography tandem mass spectrometry.

    PubMed

    Speksnijder, P; van Ravestijn, J; de Voogt, P

    2010-08-06

    Isothiazolinones are used as preservatives, biocides and disinfectants in a variety of industrial and domestic applications. Some of the isothiazolinones are difficult to isolate from water due their high polarity. A sensitive and selective analytical method was developed and optimized for the determination of sub-microg/L levels of three isothiazolinones in water samples. Three isothiazolinones are described in this paper: 2-methyl-3-isothiazolinone, 5-chloro-2-methyl-3-isothiazolinone and 4,5-dichloro-2-methyl-3-isothiazolinone. The analytical method involves a robust large-volume direct on-column loop injection of 2 mL on an Aqua ODS HPLC column and tandem MS detection (HPLC-MS/MS). After filtration, samples are directly injected without further pretreatment. Detection limits of the individual target compounds were between 0.03 and 0.1 microg/L employing Multi-Reaction Monitoring (MRM) mass spectrometry. Based on the constant ratio of two selected product-ions together with the retention time, the identification is very selective and quantification is reliable. The method was successfully applied to real samples of membrane flushings, drinking water, surface waters and waste water. Additional investigations showed the instability of the isothiazolinones in river- and waste water. Preservation of river water and waste water samples with sodium azide (NaN(3)) promotes the stability of the isothiazolines in solution. In membrane flushings, waste water, surface waters and drinking water, levels of the three isothiazolinones were all below the limit of detection. In effluents of households containing washings from normal shampoo use, isothiazolinones could be detected.

  15. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus

    SciTech Connect

    Yan, Zhaoli Tian, Hao; Cheng, Xiaobin; Yang, Jun; Chen, Bin

    2015-12-15

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10{sup −4} during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  16. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus.

    PubMed

    Yan, Zhaoli; Chen, Bin; Tian, Hao; Cheng, Xiaobin; Yang, Jun

    2015-12-01

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10(-4) during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  17. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus

    NASA Astrophysics Data System (ADS)

    Yan, Zhaoli; Chen, Bin; Tian, Hao; Cheng, Xiaobin; Yang, Jun

    2015-12-01

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10-4 during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  18. Characterizing Companions to Low-Mass Stars: A Large-Scale, Volume-Limited Survey of Local M-dwarfs

    NASA Astrophysics Data System (ADS)

    Ward-Duong, Kimberly; Patience, J.; De Rosa, R.; Rajan, A.

    2013-01-01

    M-dwarfs constitute the major fraction of stars within both the solar neighborhood and nearby star-forming regions. However, key M-dwarf companion characteristics - including multiplicity fraction, mass ratios, and separation distributions - are less certain for field stars, due to limited sample sizes and non-uniform selection criteria. Studies of star-forming regions often compare results to solar-type field stars due to the extensive population statistics available for G-dwarfs, but field M-dwarfs represent a more analogous population for comparison due to their prevalence. We present results on a stellar and substellar companion study covering separations from ~1 - 10,000 AU, based on a volume-limited survey of ~300 M-dwarfs within 15 pc. Our study constrains the frequency of binary companions and the shape of the companion separation and mass ratio distributions. Diffraction-limited, mid-to-near infrared archival data were obtained from the Very Large Telescope, Hubble Space Telescope, and Canada-France-Hawaii Telescope, to detect nearby companions to M-dwarfs from ~1 to 100 AU. To supplement the high-resolution data, wide-field archival plates were searched for companions with separations of 100 to 10,000 AU. The all-sky survey data include multiple epochs, and follow up observations at higher resolution will allow us to confirm or reject the new companion candidates detected during our analysis. These multi-epoch observations provide confirmation of common proper motions, thereby minimizing background contamination and providing comprehensive statistics for M-star binaries. Preliminary analysis of an initial subset of the sample suggests a lower limit to the multiplicity of 23 ± 7% within the restricted separation range. Characterizations of the binary frequency for M-dwarfs provide crucial insights into the low-mass star formation environment, and hold additional implications for the frequency and evolutionary histories of their associated disks and

  19. Simulation and measurement of pulse height and rise-time for electron signals in CZT detectors:. influence of material and electronics parameters

    NASA Astrophysics Data System (ADS)

    Mathy, F.; Bonnefoy, J. P.; Gliere, A.; Mestais, C.; Verger, L.

    2001-02-01

    A model for simulation of amplitude vs. rise-time biparametric spectra as a function of CZT materials properties was developed. This model takes into account the physical properties of the CZT detectors, the electric field profile and the physics of γ- ray interaction with CZT. The model has been refined to include the filtering effects of the front-end electronics and applied again to biparametric spectra. The electronic filtering is represented by a combination of linear band pass filters. The rise-time measurement circuit induces a non-linearity that is taken into account. A comparison between the electronics simulations and calibration measurements on the actual circuits is presented. In addition, physical and electrical properties of several CZT samples have been characterized and these properties have been incorporated in the model so that actual and simulated biparametric spectra can be compared. Finally, the model is applied to show the influence of the main physical parameters (mobility and lifetime) and of the applied electric field on the biparametric spectra.

  20. Advanced fractional crystallisation and homogenization of large-volume rhyolite before the Oraefajokull 1362 AD plinian eruption, SE Iceland

    NASA Astrophysics Data System (ADS)

    Selbekk, R. S.; Tronnes, R. G.

    2007-12-01

    In the 50 km wide Icelandic rift zones rhyolite magma is generated by partial melting of hydrated metabasaltic crust, subsiding under the weight of the growing volcanic pile. This mechanism of silicic melt formation is indicated by the basalt-rhyolite bimodality and rhyolite O-isotope composition. The low 18/16O-isotope ratios of rift zone rhyolites trace the high-latitude meteoric water component of the subsiding hydrated basalts [1]. The rhyolites of the volcanic flank zones (VFZ), however, have generally as heavy oxygen as the associated alkaline to transitional basalts and intermediate volcanics [2,3]. The minor volcanic loading of the older, thicker and stronger VFZ crust is insufficient for significant subsidence, and less pronounced basalt-rhyolite bimodality combined with other geochemical features support silicic melt generation by fractional crystallization. An extreme case in Icelandic, as well as global, perspective is the rhyolite magma of the plinian eruption from the large VFZ-volcano, Oraefajokull, in 1362 AD [4]. Glass, mineral and bulk tephra analyses show no chemical variation exceeding the analytical precision for the entire erupted volume of 2 km3 DRE. This applies even to the glass shards from distant locations in Greenland, Norway and Ireland. The total phenocryst content is 0.5-1 wt percent, with oligoclase (An14 Ab81 Or5.5), fayalite (Fa99.7 Fo0.3) and hedenbergite (Wo44.7 En2.6 Fs52.7) constituting 50- 80, 10-25 and 10-25 percent of the total phenocrysts, respectively. The extreme mineral compositions (especially pure fayalite and hedenbergite) resemble those of the granophyres in the Skaergaard and Bushveld complexes and differ from all other investigated rhyolites. The advanced fractionation and homogenisation to form the erupted 2 km3 DRE rhyolite is petrogenetically challenging, and a parental magma chamber of 20-40 km3 seems like a conservative estimate. The time-scale of the historic magma chamber evolution under Oraefajokull is

  1. Coded Mask Imaging of High Energy X-rays with CZT Detectors

    NASA Astrophysics Data System (ADS)

    Matteson, J. L.; Dowkontt, P. F.; Duttweiler, F.; Heindl, W. A.; Hink, P. L.; Huszar, G. L.; Kalemci, E.; Leblanc, P. C.; Rothschild, R. E.; Skelton, R. T.; Slavis, K. R.; Stephan, E. A.

    1998-12-01

    Coded mask imagers are appropriate for important objectives of high energy X-ray astronomy, e.g., gamma- ray burst localization, all-sky monitors and surveys, and deep surveys of limited regions. We report results from a coded mask imager developed to establish the proof-of-concept for this technique with CZT detectors. The detector is 2 mm thick with orthogonal crossed strip readout and an advanced electrode design to improve the energy resolution. Each detector face has 22 strip electrodes, and the strip pitch and pixel size are 500 microns. ASIC readout is used and the energy resolution varies from 3 to 6 keV FWHM over the 14 to 184 keV keV range. A coded mask with 2 x 2 cycles of a 23 x 23 MURA pattern (860 micron unit cell) was built from 600 micron thick tantalum to provide good X-ray modulation up to 200 keV. The detector, mask, and a tiny Gd-153 source of 41 keV X-rays were positioned with a spacing that caused the mask cells in the shadowgram to have a projected size of 1300 microns at the detector. Multiple detector positions were used to measure the shadowgram of a full mask cycle and this was recorded with 100 percent modulation transfer by the detector, due to its factor of 2.6 oversampling of the mask unit cell, and very high strip-to-strip selectivity and spatial accuracy. Deconvolution of the shadowgram produced a correlation image in which the source was detected as a 76-sigma peak with the correct FWHM and base diameter. Off-source image pixels had gaussian fluctuations that agree closely with the measurement statistics. Off-source image defects such as might be produced by systematic effects were too small to be seen and limited to <0.5 percent of the source peak. These results were obtained with the "raw" shadowgram and image; no "flat fielding" corrections were used.

  2. The unsettled world of leak rate physics: 1 atm large-volume considerations do not apply to MEMS packages: a practitioner's perspective

    NASA Astrophysics Data System (ADS)

    Kullberg, Richard C.; Jonath, Arthur; Lowry, Robert K.

    2012-03-01

    The world of leak testing, and the applicable physics, is unsettled. While globally lower MIL-STD leak rate criteria are under consideration even for 1 atm-large volume packages, industry is conversely moving rapidly into very small volume MEMS and vacuum packaging for advanced devices. These changes point out serious conceptual disconnects between the reality of properly characterizing a leak and the conceptual tools used to ensure the desired lifetime. The physical understandings and associated tool sets used to test and model the leaks are described. We modeled two actual packages, a large, ~200 cc volume multichip module for aerospace applications and a small ~0.01cc volume MEMS package for sensor applications. Impacts of various physical models of leak flow into a package are compared to include Fickian Diffusion, The Davy Model, Howl-Mann, and an empirically derived model based on Kr-85 leak testing as called out in the most recent edition of MIL-STD-883. As shown in the comparisons, simple He leak testing and physical models based thereon fall apart in the small volume MEMS packaging space.

  3. Origin of Large Felsic Rock Volumes in Marie Byrd Land Volcanoes:Possible Influence of Tectonic Environment and Continental Lithospheric Structure

    NASA Astrophysics Data System (ADS)

    Lemasurier, W. E.

    2002-12-01

    The Marie Byrd Land volcanic province, in the West Antarctic rift system, includes several volcanoes with large volumes of peralkaline trachyte, phonolite, and rhyolite. The roughly 780 cu. km. of trachyte at Mt. Takahe volcano, for example, is about twice the volume of Mt. Shasta, the largest Cascade volcano.Geochemical data provide evidence for only minor amounts of crustal contamination, affecting just a small proportion of the felsic rocks, hence crustal assimilation is unlikely to have supplemented the volume of felsic rocks. Most appear to have been derived entirely by fractional crystallization of basaltic magma; but the volumes of felsic rock in Marie Byrd Land volcanoes is much larger than is found in their counterparts in oceanic islands, produced by essentially the same process, suggesting that continental structure and/or tectonic environment may have played a role in felsic rock evolution. The absence of Antarctic plate motion, over at least the past 26 m.y., seems an obvious factor. This has apparently led to repeated replenishment of the same magma chambers, rather than formation of linear chains of volcanoes. In addition, modeling results suggest that a multi-level, polybaric plumbing system within the lithosphere has acted as a filter, delaying the rise of at least some large volume magma batches, thereby prolonging and refining the fractionation process.

  4. A new adsorption-elution technique for the concentration of aquatic extracellular antibiotic resistance genes from large volumes of water.

    PubMed

    Wang, Da-Ning; Liu, Lu; Qiu, Zhi-Gang; Shen, Zhi-Qiang; Guo, Xuan; Yang, Dong; Li, Jing; Liu, Wei-Li; Jin, Min; Li, Jun-Wen

    2016-04-01

    Extracellular antibiotic resistance genes (eARGs) that help in the transmission and spread of antibiotic-resistant bacteria are emerging environmental contaminants in water, and there is therefore a growing need to assess environmental levels and associated risks of eARGs. However, as they are present in low amounts, it is difficult to detect eARGs in water directly with PCR techniques. Here, we prepared a new type of nucleic acid adsorption particle (NAAP) with high capacity and developed an optimal adsorption-elution method to concentrate eARGs from large volumes of water. With this technique, we were able to achieve an eARG recovery rate of above 95% from 10 L of water samples. Moreover, combining this new method with quantitative real-time PCR (qPCR), the sensitivity of the eARG detection was 10(4) times that of single qPCR, with the detection limit lowered to 100 gene copies (GCs)/L. Our analyses showed that the eARG load, virus load and certain water characteristics such as pH, chemical oxygen demand (CODMn), and turbidity affected the eARGs recovery rate. However, high eARGs recovery rates always remained within the standard limits for natural surface water quality, while eARG levels in water were lower than the detection limits of single qPCR assays. The recovery rates were not affected by water temperature and heterotrophic plate counts (HPC). The eARGs whatever located in the plasmids or the short-length linear DNAs can be recovered from the water. Furthermore, the recovery rate was high even in the presence of high concentrations of plasmids in different natural water (Haihe river, well water, raw water for drinking water, Jinhe river, Tuanbo lake and the Yunqiao reservoir). By this technology, eARGs concentrations were found ranging from (2.70 ± 0.73) × 10(2) to (4.58 ± 0.47) × 10(4) GCs/L for the extracellular ampicillin resistance gene and (5.43 ± 0.41) × 10(2) to (2.14 ± 0.23) × 10(4) GCs/L for the extracellular gentamicin

  5. Evaluation of position-estimation methods applied to CZT-based photon-counting detectors for dedicated breast CT

    PubMed Central

    Makeev, Andrey; Clajus, Martin; Snyder, Scott; Wang, Xiaolang; Glick, Stephen J.

    2015-01-01

    Abstract. Semiconductor photon-counting detectors based on high atomic number, high density materials [cadmium zinc telluride (CZT)/cadmium telluride (CdTe)] for x-ray computed tomography (CT) provide advantages over conventional energy-integrating detectors, including reduced electronic and Swank noise, wider dynamic range, capability of spectral CT, and improved signal-to-noise ratio. Certain CT applications require high spatial resolution. In breast CT, for example, visualization of microcalcifications and assessment of tumor microvasculature after contrast enhancement require resolution on the order of 100  μm. A straightforward approach to increasing spatial resolution of pixellated CZT-based radiation detectors by merely decreasing the pixel size leads to two problems: (1) fabricating circuitry with small pixels becomes costly and (2) inter-pixel charge spreading can obviate any improvement in spatial resolution. We have used computer simulations to investigate position estimation algorithms that utilize charge sharing to achieve subpixel position resolution. To study these algorithms, we model a simple detector geometry with a 5×5 array of 200  μm pixels, and use a conditional probability function to model charge transport in CZT. We used COMSOL finite element method software to map the distribution of charge pulses and the Monte Carlo package PENELOPE for simulating fluorescent radiation. Performance of two x-ray interaction position estimation algorithms was evaluated: the method of maximum-likelihood estimation and a fast, practical algorithm that can be implemented in a readout application-specific integrated circuit and allows for identification of a quadrant of the pixel in which the interaction occurred. Both methods demonstrate good subpixel resolution; however, their actual efficiency is limited by the presence of fluorescent K-escape photons. Current experimental breast CT systems typically use detectors with a pixel size of 194

  6. Portable waveguide display system with a large field of view by integrating freeform elements and volume holograms

    PubMed Central

    Han, Jian; Liu, Juan; Yao, Xincheng; Wang, Yongtian

    2015-01-01

    A compact waveguide display system integrating freeform elements and volume holograms is presented here for the first time. The use of freeform elements can broaden the field of view, which limits the applications of a holographic waveguide. An optimized system can achieve a diagonal field of view of 45° when the thickness of the waveguide planar is 3mm. Freeform-elements in-coupler and the volume holograms out-coupler were designed in detail in our study, and the influence of grating configurations on diffraction efficiency was analyzed thoroughly. The off-axis aberrations were well compensated by the in-coupler and the diffraction efficiency of the optimized waveguide display system could reach 87.57%. With integrated design, stability and reliability of this monochromatic display system were achieved and the alignment of the system was easily controlled by the record of the volume holograms, which makes mass production possible. PMID:25836207

  7. Derivation and representation of dose-volume response from large clinical trial data sets: an example from the RADAR prostate radiotherapy trial

    NASA Astrophysics Data System (ADS)

    Ebert, M. A.; Foo, K.; Haworth, A.; Gulliford, S. L.; Kearvall, R.; Kennedy, A.; Richardson, S.; Krawiec, M.; Stewart, N.; Joseph, D. J.; Denham, J. W.

    2014-03-01

    Large multicentre radiotherapy trials incorporating assessment of multiple outcomes at multiple timepoints can generate extensive datasets. We have investigated graphical techniques for presentation of this data and the associated underlying dose-volume response information, necessary for guiding statistical analyses and translating outcomes to future patient treatments. A relational database was used to archive reviewed plan data for patients accrued to the TROG 03.04 RADAR trial. Viewing software was used to clean and enhance the data. Scripts were developed to export arbitrary dose-histogram data which was combined with clinical toxicity data with a median follow-up of 72 months. Graphical representations of dose-volume response developed include prevalence atlasing, univariate logistic regression and dose-volume-point odds ratios, and continuous cut-point derivation via ROC analysis. These representations indicate variable association of toxicities across structures and time-points.

  8. Results of volume-staged fractionated Gamma Knife radiosurgery for large complex arteriovenous malformations: obliteration rates and clinical outcomes of an evolving treatment paradigm.

    PubMed

    Franzin, Alberto; Panni, Pietro; Spatola, Giorgio; Vecchio, Antonella Del; Gallotti, Alberto L; Gigliotti, Carmen R; Cavalli, Andrea; Donofrio, Carmine A; Mortini, Pietro

    2016-12-01

    OBJECTIVE There are few reported series regarding volume-staged Gamma Knife radiosurgery (GKRS) for the treatment of large, complex, cerebral arteriovenous malformations (AVMs). The object of this study was to report the results of using volume-staged Gamma Knife radiosurgery for patients affected by large and complex AVMs. METHODS Data from 20 patients with large AVMs were prospectively included in the authors' AVM database between 2004 and 2012. A staging strategy was used when treating lesion volumes larger than 10 cm(3). Hemorrhage and seizures were the presenting clinical feature for 6 (30%) and 8 (40%) patients, respectively. The median AVM volume was 15.9 cm(3) (range 10.1-34.3 cm(3)). The mean interval between stages (± standard deviation) was 15 months (± 9 months). The median margin dose for each stage was 20 Gy (range 18-25 Gy). RESULTS Obliteration was confirmed in 8 (42%) patients after a mean follow-up of 45 months (range 19-87 months). A significant reduction (> 75%) of the original nidal volume was achieved in 4 (20%) patients. Engel Class I-II seizure status was reported by 75% of patients presenting with seizures (50% Engel Class I and 25% Engel Class II) after radiosurgery. After radiosurgery, 71.5% (5/7) of patients who had presented with a worsening neurological deficit reported a complete resolution or amelioration. None of the patients who presented acutely because of hemorrhage experienced a new bleeding episode during follow-up. One (5%) patient developed radionecrosis that caused sensorimotor hemisyndrome. Two (10%) patients sustained a bleeding episode after GKRS, although only 1 (5%) was symptomatic. High nidal flow rate and a time interval between stages of less than 11.7 months were factors significantly associated with AVM obliteration (p = 0.021 and p = 0.041, respectively). Patient age younger than 44 years was significantly associated with a greater than 75% reduction in AVM volume but not with AVM obliteration (p = 0

  9. Hybrid vapor phase-solution phase growth techniques for improved CZT(S,Se) photovoltaic device performance

    DOEpatents

    Chang, Liang-Yi; Gershon, Talia S.; Haight, Richard A.; Lee, Yun Seog

    2016-12-27

    A hybrid vapor phase-solution phase CZT(S,Se) growth technique is provided. In one aspect, a method of forming a kesterite absorber material on a substrate includes the steps of: depositing a layer of a first kesterite material on the substrate using a vapor phase deposition process, wherein the first kesterite material includes Cu, Zn, Sn, and at least one of S and Se; annealing the first kesterite material to crystallize the first kesterite material; and depositing a layer of a second kesterite material on a side of the first kesterite material opposite the substrate using a solution phase deposition process, wherein the second kesterite material includes Cu, Zn, Sn, and at least one of S and Se, wherein the first kesterite material and the second kesterite material form a multi-layer stack of the absorber material on the substrate. A photovoltaic device and method of formation thereof are also provided.

  10. Measuring and mitigating inhibition during quantitative real time PCR analysis of viral nucleic acid extracts from large-volume environmental water samples.

    PubMed

    Gibson, K E; Schwab, K J; Spencer, S K; Borchardt, M A

    2012-09-01

    Naturally-occurring inhibitory compounds are a major concern during qPCR and RT-qPCR analysis of environmental samples, particularly large volume water samples. Here, a standardized method for measuring and mitigating sample inhibition in environmental water concentrates is described. Specifically, the method 1) employs a commercially available standard RNA control; 2) defines inhibition by the change in the quantification cycle (C(q)) of the standard RNA control when added to the sample concentrate; and 3) calculates a dilution factor using a mathematical formula applied to the change in C(q) to indicate the specific volume of nuclease-free water necessary to dilute the effect of inhibitors. The standardized inhibition method was applied to 3,193 large-volume water (surface, groundwater, drinking water, agricultural runoff, sewage) concentrates of which 1,074 (34%) were inhibited. Inhibition level was not related to sample volume. Samples collected from the same locations over a one to two year period had widely variable inhibition levels. The proportion of samples that could have been reported as false negatives if inhibition had not been mitigated was between 0.3% and 71%, depending on water source. These findings emphasize the importance of measuring and mitigating inhibition when reporting qPCR results for viral pathogens in environmental waters to minimize the likelihood of reporting false negatives and under-quantifying virus concentration.

  11. Thirty Years on--A Large Anti-Flynn Effect? The Piagetian Test Volume & Heaviness Norms 1975-2003

    ERIC Educational Resources Information Center

    Shayer, Michael; Ginsburg, Denise; Coe, Robert

    2007-01-01

    Background: "Volume & Heaviness" was one of three Piagetian tests used in the CSMS survey in 1975/76. However unlike psychometric tests showing the Flynn effect--that is with students showing steady improvements year by year requiring tests to be restandardized--it appeared that the performance of Y7 students has recently been…

  12. Development status of a CZT spectrometer prototype with 3D spatial resolution for hard x-ray astronomy

    NASA Astrophysics Data System (ADS)

    Auricchio, N.; Caroli, E.; Basili, A.; Benassi, G.; Budtz Jørgensen, C.; Curado da Silva, R. M.; Del Sordo, S.; Kuvvetli, I.; Milano, L.; Moscatelli, F.; Stephen, J. B.; Zanichelli, M.; Zappettini, A.

    2012-07-01

    The development of new focusing optics based on wide band Laue lenses operating from ~60 keV up to several hundred keV is particularly challenging. This type of hard X-ray or gamma ray optics requires a high performance focal plane detector in order to exploit to the best their intrinsic capabilities. We describe a three dimensional (3D) position sensitive detector prototype suitable as the basic module for a high efficiency Laue lens focal plane detector. This detector configuration is currently under study for use in a balloon payload dedicated to performing a high significance measurement of the polarization status of the Crab between 100 and 500 keV. The prototype is made by packing 8 linear modules, each composed of one basic sensitive unit bonded onto a thin supporting ceramic layer. Each unit is a drift strip detector based on a CZT crystal, irradiated transversally to the electric field direction. The anode is segmented into 8 detection cells, each comprising one collecting strip and 8 surrounding drift strips. The drift strips are biased by a voltage divider. The cathode is divided into 4 horizontal strips for the reconstruction of the Z interaction position. The detector readout electronics is based on RENA-3 ASIC and the data handling system uses a custom electronics based on FPGA to provide the ASIC setting, the event handling logic, and the data acquisition. This paper mainly describes the components and the status of the undergoing activities for the construction of the proposed 3D CZT prototype and shows the results of the electronics tests.

  13. A computerized tomography scan method for calculating the hernia sac and abdominal cavity volume in complex large incisional hernia with loss of domain.

    PubMed

    Tanaka, E Y; Yoo, J H; Rodrigues, A J; Utiyama, E M; Birolini, D; Rasslan, S

    2010-02-01

    Preoperative progressive pneumoperitoneum (PPP) is a safe and effective procedure in the treatment of large incisional hernia (size > 10 cm in width or length) with loss of domain (LIHLD). There is no consensus in the literature on the amount of gas that must be insufflated in a PPP program or even how long it should be maintained. We describe a technique for calculating the hernia sac volume (HSV) and abdominal cavity volume (ACV) based on abdominal computerized tomography (ACT) scanning that eliminates the need for subjective criteria for inclusion in a PPP program and shows the amount of gas that must be insufflated into the abdominal cavity in the PPP program. Our technique is indicated for all patients with large or recurrent incisional hernias evaluated by a senior surgeon with suspected LIHLD. We reviewed our experience from 2001 to 2008 of 23 consecutive hernia surgical procedures of LIHLD undergoing preoperative evaluation with CT scanning and PPP. An ACT was required in all patients with suspected LIHLD in order to determine HSV and ACV. The PPP was performed only if the volume ratio HSV/ACV (VR = HSV/ACV) was >or=25% (VR >or= 25%). We have performed this procedure on 23 patients, with a mean age of 55.6 years (range 31-83). There were 16 women and 7 men with an average age of 55.6 years (range 31-83), and a mean BMI of 38.5 kg/m(2) (range 23-55.2). Almost all patients (21 of 23 patients-91.30%) were overweight; 43.5% (10 patients) were severely obese (obese class III). The mean calculated volumes for ACV and HSV were 9,410 ml (range 6,060-19,230 ml) and 4,500 ml (range 1,850-6,600 ml), respectively. The PPP is performed by permanent catheter placed in a minor surgical procedure. The total amount of CO(2) insufflated ranged from 2,000 to 7,000 ml (mean 4,000 ml). Patients required a mean of 10 PPP sessions (range 4-18) to achieve the desired volume of gas (that is the same volume that was calculated for the hernia sac). Since PPP sessions were performed

  14. Large-volume lava flows fed by a deep magmatic reservoir at Ağrı Dağı (Ararat) volcano, Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Karaoğlu, Özgür; Elshaafi, Abdelsalam; Salah, Mohamed K.; Browning, John; Gudmundsson, Agust

    2017-02-01

    Ağrı Dağı (Ararat), whilst being the tallest volcano in Turkey, is largely understudied. Two predominant peaks, Greater and Lesser Ağrı, make up the main edifice, which has been built during four main phases. The most recent phase consisted of two volcanic eruptions. The respective surface area and volume of the first volcanic eruption were estimated at 96 km2 and 3.2 km3, whereas those of the second eruption were much smaller with the surface area and volume estimated at 25 km2 and 0.6 km3. It is unusual for stratovolcanoes to produce basaltic eruptions of more than 3 km3, although these and larger volumes are not uncommon in flood basalt-type eruptions. Large basaltic eruptions from stratovolcanoes normally require volcano-tectonic forcing (e.g. subsidence of collapse caldera and graben). However, there is no evidence for such volcano-tectonic forcing, during the most recent eruptions at Ağrı Dağı (Ararat), and therefore, their comparatively large volume basaltic lavas need to be explained in a different way. Here, we present an analytical method for calculating the source volume needed to supply magma to the eruptions at Ağrı Dağı. We found that the lava flow of 3.2 km3 was likely fed by a very large magma reservoir (˜13,000 km3), while the second flow of 0.6 km3 was fed by a reservoir of a much smaller effective size (or ˜2000 km3). `Effective size' depends on what fraction of the reservoir participates in the eruption. We propose that the entire reservoir supplied magma to the larger eruption, but only one of its compartments (about one fifth of the total volume of the reservoir) supplied magma to the smaller eruption. Although seismic tomography indicates a magma reservoir at great depths (>20-30 km) below the Ağrı Dağı volcano, geochemical constraints on some of the later-formed rocks suggest an interaction between a shallow chamber (at 8-10-km depth) and the deep reservoir approximately 0.5 Ma. We provide numerical models whose results

  15. Genetic influences on schizophrenia and subcortical brain volumes: large-scale proof-of-concept and roadmap for future studies

    PubMed Central

    Anttila, Verneri; Hibar, Derrek P; van Hulzen, Kimm J E; Arias-Vasquez, Alejandro; Smoller, Jordan W; Nichols, Thomas E; Neale, Michael C; McIntosh, Andrew M; Lee, Phil; McMahon, Francis J; Meyer-Lindenberg, Andreas; Mattheisen, Manuel; Andreassen, Ole A; Gruber, Oliver; Sachdev, Perminder S; Roiz-Santiañez, Roberto; Saykin, Andrew J; Ehrlich, Stefan; Mather, Karen A; Turner, Jessica A; Schwarz, Emanuel; Thalamuthu, Anbupalam; Shugart, Yin Yao; Ho, Yvonne YW; Martin, Nicholas G; Wright, Margaret J

    2016-01-01

    Schizophrenia is a devastating psychiatric illness with high heritability. Brain structure and function differ, on average, between schizophrenia cases and healthy individuals. As common genetic associations are emerging for both schizophrenia and brain imaging phenotypes, we can now use genome-wide data to investigate genetic overlap. Here we integrated results from common variant studies of schizophrenia (33,636 cases, 43,008 controls) and volumes of several (mainly subcortical) brain structures (11,840 subjects). We did not find evidence of genetic overlap between schizophrenia risk and subcortical volume measures either at the level of common variant genetic architecture or for single genetic markers. The current study provides proof-of-concept (albeit based on a limited set of structural brain measures), and defines a roadmap for future studies investigating the genetic covariance between structural/functional brain phenotypes and risk for psychiatric disorders. PMID:26854805

  16. Evaluation of different adsorbents for large-volume pre-concentration for analyzing atmospheric persistent organic pollutants at trace levels.

    PubMed

    Avino, Pasquale; Cinelli, Giuseppe; Notardonato, Ivan; Russo, Mario Vincenzo

    2011-07-01

    This paper investigates the performance of some adsorbents, Carbopack B, Tenax-GC, and XAD-2, in a SPE and GC analytical method for sampling and determining some persistent organic pollutants such as benzene, toluene, o-, m-, and p-xylenes, naphthalene, anthracene, fluorene, fluoranthene, benzo(i,k)fluorene, pyrene and benzo(a)pyrene, aldrin, dieldrin, endrin, endosulfan, and PCB congeners (nos. 1, 15, 44, 77, and 209). Adsorbents evaluated in this study are Carbopack B, Tenax-GC, and XAD-2. Before applying the analytical method to air samples, it was widely investigated in laboratory: the sampler is constituted by a glass pyrex vial home-filled with 300 mg (sampling section) and 50 mg of adsorbent material (backup section). The re-extraction is performed by CS(2) (1-2 mL) and analysis is performed by GC-FID and GC-ECD. The evaluation of breakthrough volumes and desorption efficiencies shows the XAD-2 performance in the enrichment of different organic species present in atmosphere at trace levels (ppt) to be more advantageous than the other two materials in terms of analytical and technical parameters. One of the advantages is the high volume of sampled air with high concentration factor and limited loss of analytes (breakthrough volumes are higher than 5,000 L g(-1) for high-boiling compounds and higher than 400 L g(-1) for low-boiling solutes). Another advantage is the possibility of easy and speed re-extraction of analytes using small volumes of solvent (a few milliliters). The recoveries are about 100% with a RSD ≤ 2.3 for low-boiling compounds, and between 77% and 109% with a RSD ≤ 5.7% for high-boiling species. The XAD-2 adsorbent was applied to real air samples collected in different polluted areas (urban, industrial, rural, and remote locations) demonstrating the wide application of such methodology in various environmental situation.

  17. Quantifying the Impact of Immediate Reconstruction in Postmastectomy Radiation: A Large, Dose-Volume Histogram-Based Analysis

    SciTech Connect

    Ohri, Nisha; Cordeiro, Peter G.; Keam, Jennifer; Ballangrud, Ase; Shi Weiji; Zhang Zhigang; Nerbun, Claire T.; Woch, Katherine M.; Stein, Nicholas F.; Zhou Ying; McCormick, Beryl; Powell, Simon N.; Ho, Alice Y.

    2012-10-01

    Purpose: To assess the impact of immediate breast reconstruction on postmastectomy radiation (PMRT) using dose-volume histogram (DVH) data. Methods and Materials: Two hundred forty-seven women underwent PMRT at our center, 196 with implant reconstruction and 51 without reconstruction. Patients with reconstruction were treated with tangential photons, and patients without reconstruction were treated with en-face electron fields and customized bolus. Twenty percent of patients received internal mammary node (IMN) treatment. The DVH data were compared between groups. Ipsilateral lung parameters included V20 (% volume receiving 20 Gy), V40 (% volume receiving 40 Gy), mean dose, and maximum dose. Heart parameters included V25 (% volume receiving 25 Gy), mean dose, and maximum dose. IMN coverage was assessed when applicable. Chest wall coverage was assessed in patients with reconstruction. Propensity-matched analysis adjusted for potential confounders of laterality and IMN treatment. Results: Reconstruction was associated with lower lung V20, mean dose, and maximum dose compared with no reconstruction (all P<.0001). These associations persisted on propensity-matched analysis (all P<.0001). Heart doses were similar between groups (P=NS). Ninety percent of patients with reconstruction had excellent chest wall coverage (D95 >98%). IMN coverage was superior in patients with reconstruction (D95 >92.0 vs 75.7%, P<.001). IMN treatment significantly increased lung and heart parameters in patients with reconstruction (all P<.05) but minimally affected those without reconstruction (all P>.05). Among IMN-treated patients, only lower lung V20 in those without reconstruction persisted (P=.022), and mean and maximum heart doses were higher than in patients without reconstruction (P=.006, P=.015, respectively). Conclusions: Implant reconstruction does not compromise the technical quality of PMRT when the IMNs are untreated. Treatment technique, not reconstruction, is the primary

  18. Design aspects of a compact, single-frequency, permanent magnet ECR ion source with a large uniformly distributed resonant plasma volume

    SciTech Connect

    Liu, Y.; Alton, G.D.; Mills, G.D.; Reed, C.A.; Haynes, D.L.

    1997-09-01

    A compact, all-permanent-magnet single-frequency ECR ion source with a large uniformly distributed ECR plasma volume has been designed and is presently under construction at the Oak Ridge National Laboratory (ORNL). The central region of the field is designed to achieve a flat-field (constant mod-B) which extends over the length of the central field region along the axis of symmetry and radially outward to form a uniformly distributed ECR plasma volume. The magnetic field design strongly contrasts with those used in conventional ECR ion sources where the central field regions are approximately parabolic and the consequent ECR zones are surfaces. The plasma confinement magnetic field mirror has a mirror ratio B{sub max}/B{sub ECR} of slightly greater than two. The source is designed to operate at a nominal RF frequency of 6 GHz. The central flat magnetic field region can be easily adjusted by mechanical means to tune the source to the resonant conditions within the limits of 5.5 to 6.8 GHz. The RF injection system is broadband to ensure excitation of transverse electric (TE) modes so that the RF power is largely concentrated in the resonant plasma volume which lies along and surrounds the axis of symmetry of the source. Because of the much larger ECR zone, the probability for absorption of microwave power is dramatically increased thereby increasing the probability for acceleration of electrons, the electron temperature of the plasma and, consequently, the hot electron population within the plasma volume of the source. The creation of an ECR volume rather than a surface is commensurate with higher charge states and higher beam intensities within a particular charge state.

  19. Large optics technology; Proceedings of the Meeting, San Diego, CA, August 19-21, 1985. Volume 571

    SciTech Connect

    Sanger, G.M.

    1986-01-01

    The present conference on telescope primary mirror design and manufacturing technologies considers topics in mirror fabrication and testing, novel technology currently under development, recently instituted large optics development programs, and large mirror materials. Among the topics discussed are aspheric figure generation using feedback from an IR phase-shifting interferometer, thermal stability tests of CFRP sandwich panels for far-IR astronomy, Zerodur lightweight (large mirror) blanks, and the precision machining of grazing-incidence X-ray mirror substrates. Also treated are the rapid fabrication of large aspheric optics, steps toward 8-m honeycomb mirrors, a novel telescope design employing the refraction of prism rows, telescope technology for the Far-UV Spectroscopic Explorer, hot isostatic-pressed Be for large optics, and a concept for a moderate cost large deployable reflector.

  20. A novel porous bioceramics scaffold by accumulating hydroxyapatite spherulites for large bone tissue engineering in vivo. II. Construct large volume of bone grafts.

    PubMed

    Zhi, Wei; Zhang, Cong; Duan, Ke; Li, Xiaohong; Qu, Shuxin; Wang, Jianxin; Zhu, Zhuoli; Huang, Peng; Xia, Tian; Liao, Ga; Weng, Jie

    2014-08-01

    In vivo engineering of bone autografts using bioceramic scaffolds with appropriate porous structures is a potential approach to prepare autologous bone grafts for the repair of critical-sized bone defects. This study investigated the evolutionary process of osteogenesis, angiogenesis, and compressive strength of bioceramic scaffolds implanted in two non-osseous sites of dogs: the abdominal cavity and the dorsal muscle. Hydroxyapatite (HA) sphere-accumulated scaffolds with controlled porous structures were prepared and placed in the two sites for up to 6 months. Analyses of retrieved scaffolds found that osteogenesis and angiogenesis were faster in scaffolds implanted in dorsal muscles compared with those placed in abdominal cavities. The abdominal cavity, however, can accommodate larger bone grafts with designed shape. Analyses of scaffolds implanted in abdominal cavities [an environment of a low mesenchymal stem cell (MSC) density] further demonstrated that angiogenesis play critical roles during osteogenesis in the scaffolds, presumably by supplying progenitor cells and/or MSCs as seed cells. This study also examined the relationship between the volume of bone grafts and the physiological environment of in vivo bioreactor. These results provide basic information for the selection of appropriate implanting sites and culture time required to engineer autologous bone grafts for the clinical bone defect repair. Based on these positive results, a pilot study has applied the grafts constructed in canine abdominal cavity to repair segmental bone defect in load-bearing sites (limbs).

  1. Northeast Artificial Intelligence Consortium Annual Report 1986. Volume 6. Part A. Computer Architectures for Very Large Knowledge Bases

    DTIC Science & Technology

    1988-06-01

    that efficiently manage very large knowledge bases (VLKB) in a real time environment. There is a current need for expert systems with large and very...large knowledge bases. With these systems comes the problem of the efficient management of the knowledge base. Database management system technology can...approaches. The context cf our knowledge base management research is that of logic programming. That is, the inferencing mechanism is written in a logic

  2. Multiphase flow modelling using non orthogonal collocated finite volumes : application to fluid catalytical cracking and large scale geophysical flows.

    NASA Astrophysics Data System (ADS)

    Martin, R. M.; Nicolas, A. N.

    2003-04-01

    A modeling approach of gas solid flow, taking into account different physical phenomena such as gas turbulence and inter-particle interactions is presented. Moment transport equations are derived for the second order fluctuating velocity tensor which allow to involve practical closures based on single phase turbulence modeling on one hand and kinetic theory of granular media on the other hand. The model is applied to fluid catalytic cracking processes and explosive volcanism. In the industry as well as in the geophysical community, multiphase flows are modeled using a finite volume approach and a multicorrector algorithm in time in order to determine implicitly the pressures, velocities and volume fractions for each phase. Pressures, and velocities are generally determined at mid-half mesh step from each other following the staggered grid approach. This ensures stability and prevents oscillations in pressure. It allows to treat almost all the Reynolds number ranges for all speeds and viscosities. The disadvantages appear when we want to treat more complex geometries or if a generalized curvilinear formulation of the conservation equations is considered. Too many interpolations have to be done and accuracy is then lost. In order to overcome these problems, we use here a similar algorithm in time and a Rhie and Chow interpolation (1983) of the collocated variables and essentially the velocities at the interface. The Rhie and Chow interpolation of the velocities at the finite volume interfaces allows to have no oscillations of the pressure without checkerboard effects and to stabilize all the algorithm. In a first predictor step, fluxes at the interfaces of the finite volumes are then computed using 2nd and 3rd order shock capturing schemes of MUSCL/TVD or Van Leer type, and the orthogonal stress components are treated implicitly while cross viscous/diffusion terms are treated explicitly. Pentadiagonal linear systems are solved in each geometrical direction (the so

  3. Thermal analysis of the growth process of synthetic diamond in the large volume cubic press apparatus with large deformation of high pressure cell

    NASA Astrophysics Data System (ADS)

    Zhang, Qingchao; Li, Rui; Gu, Xue; Qin, Jieming; Jia, Xiaopeng; Ma, Hongan

    2015-06-01

    The temperature-field in diamond synthesis cell was simulated by a finite element method. A three-dimensional model of the China-type cubic press with large deformation of the synthesis cell was established successfully, which has been verified by situ measurements of synthesis cell. In addition, the distributions of temperature and its gradient in the synthesis sample were described. We found there is a large temperature drop in the synthesis sample, which brings some uncertainties in a synthesis process, such as the phenomenon of "wasteland, on which there is no nucleation and growth of diamond". Furthermore, the formation mechanism of wasteland was studied in detail. It indicates that the wasteland is inevitably exists in the synthesis sample, the distribution of growth region of the diamond with hex-octahedral is move to the center of the synthesis sample from near the heater as the power increasing, and the growth conditions of high quality diamond is locate at the center of the synthesis sample. This work can offer suggestion and advice to the development and optimization of a diamond production process.

  4. Associations Between Retinal Pigment Epithelium and Drusen Volume Changes During the Lifecycle of Large Drusenoid Pigment Epithelial Detachments

    PubMed Central

    Balaratnasingam, Chandrakumar; Yannuzzi, Lawrence A.; Curcio, Christine A.; Morgan, William H.; Querques, Giuseppe; Capuano, Vittorio; Souied, Eric; Jung, Jesse; Freund, K. Bailey

    2016-01-01

    Purpose Drusenoid pigment epithelial detachments (PEDs) are a defined path to atrophy in age-related macular degeneration (AMD). We analyzed the relationships between retinal pigment epithelium (RPE) and drusen volume changes during the PED lifecycle, using spectral-domain optical coherence tomography (SD-OCT). Methods Twenty-one cases of drusenoid PED tracked using SD-OCT through periods of growth and collapse were evaluated. Volumetric calculations and piece-wise linear regression analysis were used to determine the breakpoint between growth and collapse. Spectral-domain OCT scans were independently evaluated for the appearance of intraretinal hyperreflective foci, acquired vitelliform lesions (AVLs), and disruptions to the RPE+basal lamina band. Timing of these events with respect to the breakpoint was statistically evaluated. Morphometric characteristics of drusenoid PEDs were correlated with rate of PED collapse and final visual acuity. Results Mean age of subjects was 75.3 years and mean period of follow up was 4.1 years (median 4.5 years; range, 0.6–6.6 years). The lifecycle of drusenoid PEDs was asymmetric, in that the rate of collapse (0.199 mm3/month) is significantly faster (P < 0.001) than the rate of growth (0.022 mm3/month). Appearance of intraretinal hyperreflective foci and AVLs preceded the breakpoint (both P < 0.001). The timing of disruptions to the RPE+basal lamina band did not differ from the breakpoint (P = 0.510). Maximal height, volume, and diameter of drusenoid PEDs were inversely correlated with final visual acuity (all P < 0.001) and positively correlated with the rate of PED collapse (all P < 0.001). Conclusions Spectral-domain OCT signatures, plausibly attributable to anteriorly migrated RPE and disintegration of the RPE layer, precede or occur simultaneously with changes in volume of drusenoid PED during the lifecycle of this lesion. PMID:27760262

  5. Correlation of the Peach Springs Tuff, a large-volume Miocene ignimbrite sheet in California and Arizona ( USA).

    USGS Publications Warehouse

    Glazner, A.F.; Nielson, J.E.; Howard, K.A.; Miller, D.M.

    1986-01-01

    The Peach Springs Tuff is a distinctive early Miocene ignimbrite deposit that was first recognized in western Arizona. Recent field studies and phenocryst analyses indicate that adjacent outcrops of similar tuff in the central and eastern Mojave Desert may be correlative. This proposed correlation implies that outcrops of the tuff are scattered over an area of at least 35 000 km2 from the western Colorado Plateau to Barstow, California, and that the erupted volume, allowing for posteruption crustal extension, was at least several hundred cubic kilometres. Thus, the Peach Springs Tuff may be a regional stratigraphic marker, useful for determining regional paleogeography and the time and extent of Tertiary crustal extension. -Authors

  6. Containment at the Source during Waste Volume Reduction of Large Radioactive Components Using Oxylance High-Temperature Cutting Equipment - 13595

    SciTech Connect

    Keeney, G. Neil

    2013-07-01

    As a waste-volume reduction and management technique, highly contaminated Control Element Drive Mechanism (CEDM) housings were severed from the Reactor Pressure Vessel Head (RPVH) inside the San Onofre Unit 2 primary containment utilizing Oxylance high-temperature cutting equipment and techniques. Presented are relevant data concerning: - Radiological profiles of the RPVH and individual CEDMs; - Design overviews of the engineering controls and the specialized confinement housings; - Utilization of specialized shielding; - Observations of apparent metallurgical-contamination coalescence phenomena at high temperatures resulting in positive control over loose-surface contamination conditions; - General results of radiological and industrial hygiene air sampling and monitoring; - Collective dose and personnel contamination event statistics; - Lessons learned. (author)

  7. SemiSPECT: A small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays

    PubMed Central

    Kim, Hyunki; Furenlid, Lars R.; Crawford, Michael J.; Wilson, Donald W.; Barber, H. Bradford; Peterson, Todd E.; Hunter, William C. J.; Liu, Zhonglin; Woolfenden, James M.; Barrett, Harrison H.

    2008-01-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm × 2.7 cm × ~ 0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 × 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of −180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 × 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 × 10−4 with the energy window of ±10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT. PMID:16532954

  8. Performance evaluation of high-resolution square parallel-hole collimators with a CZT room temperature pixelated semiconductor SPECT system: a Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Kang, W.

    2015-07-01

    The pixelated semiconductor based on cadmium zinc telluride (CZT) is a promising imaging device that provides many benefits compared with conventional scintillation detectors. By using a high-resolution square parallel-hole collimator with a pixelated semiconductor detector, we were able to improve both sensitivity and spatial resolution. Here, we present a simulation of a CZT pixleated semiconductor single-photon emission computed tomography (SPECT) system with a high-resolution square parallel-hole collimator using various geometric designs of 0.5, 1.0, 1.5, and 2.0 mm X-axis hole size. We performed a simulation study of the eValuator-2500 (eV Microelectronics Inc., Saxonburg, PA, U.S.A.) CZT pixelated semiconductor detector using a Geant4 Application for Tomographic Emission (GATE). To evaluate the performances of these systems, the sensitivity and spatial resolution was evaluated. Moreover, to evaluate the overall performance of the imaging system, a hot-rod phantom was designed. Our results showed that the average sensitivity of the 2.0 mm collimator X-axis hole size was 1.34, 1.95, and 3.92 times higher than that of the 1.5, 1.0, and 0.5 mm collimator X-axis hole size, respectively. Also, the average spatial resolution of the 0.5 mm collimator X-axis hole size was 28.69, 44.65, and 55.73% better than that of the 1.0, 1.5, and 2.0 mm collimator X-axis hole size, respectively. We discuss the high-resolution square parallel-hole collimator of various collimator geometric designs and our evaluations. In conclusion, we have successfully designed a high-resolution square parallel-hole collimator with a CZT pixelated semiconductor SPECT system.

  9. SemiSPECT: a small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays.

    PubMed

    Kim, Hyunki; Furenlid, Lars R; Crawford, Michael J; Wilson, Donald W; Barber, H Bradford; Peterson, Todd E; Hunter, William C J; Liu, Zhonglin; Woolfenden, James M; Barrett, Harrison H

    2006-02-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm x 2.7 cm x -0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 x 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of -180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 x 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 x 10(-4) with the energy window of +/-10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT.

  10. [Determination of trace and ultra-trace level bromate in water by large volume sample injection with enrichment column for on-line preconcentration coupled with ion chromatography].

    PubMed

    Liu, Jing; He, Qingqing; Yang, Lili; Hu, Enyu; Wang, Meifei

    2015-10-01

    A method for the determination of trace and ultra-trace level bromate in water by ion chromatography with large volume sample injection for on-line preconcentration was established. A high capacity Dionex IonPac AG23 guard column was simply used as the enrichment column instead of the loop for the preconcentration of bromate. High purity KOH solution used as eluent for gradient elution was on-line produced by an eluent generator automatically. The results showed that a good linear relationship of bromate was exhibited in the range of 0.05-51.2 μg/L (r ≥ 0.999 5), and the method detection limit was 0.01 μg/L. Compared with conventional sample injection, the injection volume was up to 5 mL, and the enrichment factor of this method was about 240 times. This method was successfully applied for several real samples of pure water which were purchased in the supermarket, and the recoveries of bromate were between 90%-100% with the RSDs (n = 6) of 2.1%-6.4% at two spiked levels. This method without pretreatment is simple, and of high accuracy and precision. The preconcentration can be achieved by large volume sample injection. It is suitable for the analysis of trace and ultra-trace level bromate.

  11. Cryo-FIB-SEM serial milling and block face imaging: Large volume structural analysis of biological tissues preserved close to their native state.

    PubMed

    Vidavsky, Netta; Akiva, Anat; Kaplan-Ashiri, Ifat; Rechav, Katya; Addadi, Lia; Weiner, Steve; Schertel, Andreas

    2016-12-01

    Many important biological questions can be addressed by studying in 3D large volumes of intact, cryo fixed hydrated tissues (⩾10,000μm(3)) at high resolution (5-20nm). This can be achieved using serial FIB milling and block face surface imaging under cryo conditions. Here we demonstrate the unique potential of the cryo-FIB-SEM approach using two extensively studied model systems; sea urchin embryos and the tail fin of zebrafish larvae. We focus in particular on the environment of mineral deposition sites. The cellular organelles, including mitochondria, Golgi, ER, nuclei and nuclear pores are made visible by the image contrast created by differences in surface potential of different biochemical components. Auto segmentation and/or volume rendering of the image stacks and 3D reconstruction of the skeleton and the cellular environment, provides a detailed view of the relative distribution in space of the tissue/cellular components, and thus of their interactions. Simultaneous acquisition of secondary and back-scattered electron images adds additional information. For example, a serial view of the zebrafish tail reveals the presence of electron dense mineral particles inside mitochondrial networks extending more than 20μm in depth in the block. Large volume imaging using cryo FIB SEM, as demonstrated here, can contribute significantly to the understanding of the structures and functions of diverse biological tissues.

  12. Large-volume, low-δ18O rhyolites of the central Snake River Plain, Idaho, USA

    USGS Publications Warehouse

    Boroughs, Scott; Wolff, John; Bonnichsen, Bill; Godchaux, Martha; Larson, Peter

    2005-01-01

    The Miocene Bruneau-Jarbidge and adjacent volcanic fields of the central Snake River Plain, southwest Idaho, are dominated by high-temperature rhyolitic tuffs and lavas having an aggregate volume estimated as 7000 km3. Samples from units representing at least 50% of this volume are strongly depleted in 18O, with magmatic feldspar δ18OVSMOW (Vienna standard mean ocean water) values between −1.4‰ and 3.8‰. The magnitude of the 18O depletion and the complete lack of any rhyolites with normal values (7‰–10‰) combine to suggest that assimilation or melting of a caldera block altered by near- contemporaneous hydrothermal activity is unlikely. Instead, we envisage generation of the high-temperature rhyolites by shallow melting of Idaho Batholith rocks, under the influence of the Yellowstone hotspot, affected by Eocene meteoric-hydrothermal events. The seeming worldwide scarcity of strongly 18O-depleted rhyolites may simply reflect a similar scarcity of suitable crustal protoliths.

  13. Small-volume chylous ascites after laparoscopic radical gastrectomy for gastric cancer: Results from a large population-based sample

    PubMed Central

    Lu, Jun; Wei, Zhen-Quan; Huang, Chang-Ming; Zheng, Chao-Hui; Li, Ping; Xie, Jian-Wei; Wang, Jia-Bin; Lin, Jian-Xian; Chen, Qi-Yue; Cao, Long-Long; Lin, Mi

    2015-01-01

    AIM: To report the incidence and potential risk factors of small-volume chylous ascites (SVCA) following laparoscopic radical gastrectomy (LAG). METHODS: A total of 1366 consecutive gastric cancer patients who underwent LAG from January 2008 to June 2011 were enrolled in this study. We analyzed the patients based on the presence or absence of SVCA. RESULTS: SVCA was detected in 57 (4.17%) patients, as determined by the small-volume drainage (range, 30-100 mL/24 h) of triglyceride-rich fluid. Both univariate and multivariate analyses revealed that the total number of resected lymph nodes (LNs), No. 8 or No. 9 LN metastasis and N stage were independent risk factors for SVCA following LAG (P < 0.05). Regarding hospital stay, there was a significant difference between the groups with and without SVCA (P < 0.001). The 3-year disease-free and overall survival rates of the patients with SVCA were 47.4% and 56.1%, respectively, which were similar to those of the patients without SVCA (P > 0.05). CONCLUSION: SVCA following LAG developed significantly more frequently in the patients with ≥ 32 harvested LNs, ≥ 3 metastatic LNs, or No. 8 or No. 9 LN metastasis. SVCA, which was successfully treated with conservative management, was associated with a prolonged hospital stay but was not associated with the prognosis. PMID:25741151

  14. MIDAS prototype Multispectral Interactive Digital Analysis System for large area earth resources surveys. Volume 2: Charge coupled device investigation

    NASA Technical Reports Server (NTRS)

    Kriegler, F.; Marshall, R.; Sternberg, S.

    1976-01-01

    MIDAS is a third-generation, fast, low cost, multispectral recognition system able to keep pace with the large quantity and high rates of data acquisition from large regions with present and projected sensors. MIDAS, for example, can process a complete ERTS frame in forty seconds and provide a color map of sixteen constituent categories in a few minutes. A principal objective of the MIDAS Program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The need for advanced onboard spacecraft processing of remotely sensed data is stated and approaches to this problem are described which are feasible through the use of charge coupled devices. Tentative mechanizations for the required processing operations are given in large block form. These initial designs can serve as a guide to circuit/system designers.

  15. Initial evaluation of a modified dual-energy window scatter correction method for CZT-based gamma cameras for breast SPECT

    NASA Astrophysics Data System (ADS)

    Mann, Steve D.; Tornai, Martin P.

    2015-03-01

    Solid state Cadmium Zinc Telluride (CZT) gamma cameras for SPECT imaging offer significantly improved energy resolution compared to traditional scintillation detectors. However, the photopeak resolution is often asymmetric due to incomplete charge collection within the detector, resulting in many photopeak events incorrectly sorted into lower energy bins ("tailing"). These misplaced events contaminate the true scatter signal, which may negatively impact scatter correction methods that rely on estimates of scatter from the spectra. Additionally, because CZT detectors are organized into arrays, each individual detector element may exhibit different degrees of tailing. Here, we present a modified dualenergy window scatter correction method for emission detection and imaging that attempts to account for positiondependent effects of incomplete charge collection in the CZT gamma camera of our dedicated breast SPECT-CT system. Point source measurements and geometric phantoms were used to estimate the impact of tailing on the scatter signal and extract a better estimate of the ratio of scatter within two energy windows. To evaluate the method, cylindrical phantoms with and without a separate fillable chamber were scanned to determine the impact on quantification in hot, cold, and uniform background regions. Projections were reconstructed using OSEM, and the results for the traditional and modified scatter correction methods were compared. Results show that while modest reduced quantification accuracy was observed in hot and cold regions of the multi-chamber phantoms, the modified scatter correction method yields up to 8% improved quantification accuracy with 4% less added noise than the traditional DEW method within uniform background regions.

  16. Large-volume reconstruction of brain tissue from high-resolution serial section images acquired by SEM-based scanning transmission electron microscopy.

    PubMed

    Kuwajima, Masaaki; Mendenhall, John M; Harris, Kristen M

    2013-01-01

    With recent improvements in instrumentation and computational tools, serial section electron microscopy has become increasingly straightforward. A new method for imaging ultrathin serial sections is developed based on a field emission scanning electron microscope fitted with a transmitted electron detector. This method is capable of automatically acquiring high-resolution serial images with a large field size and very little optical and physical distortions. In this chapter, we describe the procedures leading to the generation and analyses of a large-volume stack of high-resolution images (64 μm × 64 μm × 10 μm, or larger, at 2 nm pixel size), including how to obtain large-area serial sections of uniform thickness from well-preserved brain tissue that is rapidly perfusion-fixed with mixed aldehydes, processed with a microwave-enhanced method, and embedded into epoxy resin.

  17. Assessment of a novel device for onsite integrative large-volume solid phase extraction of water samples to enable a comprehensive chemical and effect-based analysis.

    PubMed

    Schulze, Tobias; Ahel, Marijan; Ahlheim, Jörg; Aït-Aïssa, Selim; Brion, François; Di Paolo, Carolina; Froment, Jean; Hidasi, Anita O; Hollender, Juliane; Hollert, Henner; Hu, Meng; Kloß, Anett; Koprivica, Sanja; Krauss, Martin; Muz, Melis; Oswald, Peter; Petre, Margit; Schollée, Jennifer E; Seiler, Thomas-Benjamin; Shao, Ying; Slobodnik, Jaroslav; Sonavane, Manoj; Suter, Marc J-F; Tollefsen, Knut Erik; Tousova, Zuzana; Walz, Karl-Heinz; Brack, Werner

    2017-03-01

    The implementation of targeted and nontargeted chemical screening analysis in combination with in vitro and organism-level bioassays is a prerequisite for a more holistic monitoring of water quality in the future. For chemical analysis, little or no sample enrichment is often sufficient, while bioanalysis often requires larger sample volumes at a certain enrichment factor for conducting comprehensive bioassays on different endpoints or further effect-directed analysis (EDA). To avoid logistic and technical issues related to the storage and transport of large volumes of water, sampling would benefit greatly from onsite extraction. This study presents a novel onsite large volume solid phase extraction (LVSPE) device tailored to fulfill the requirements for the successful effect-based and chemical screening of water resources and complies with available international standards for automated sampling devices. Laboratory recovery experiments using 251 organic compounds in the log D range from -3.6 to 9.4 (at pH7.0) spiked into pristine water resulted in acceptable recoveries and from 60 to 123% for 159 out of 251 substances. Within a European-wide demonstration program, the LVSPE was able to enrich compounds in concentration ranges over three orders of magnitude (1ngL(-1) to 2400ngL(-1)). It was possible to discriminate responsive samples from samples with no or only low effects in a set of six different bioassays (i.e. acetylcholinesterase and algal growth inhibition, androgenicity, estrogenicity, fish embryo toxicity, glucocorticoid activity). The LVSPE thus proved applicable for onsite extraction of sufficient amounts of water to investigate water quality thoroughly by means of chemical analysis and effect-based tools without the common limitations due to small sample volumes.

  18. Dosimetric Coverage of the Prostate, Normal Tissue Sparing, and Acute Toxicity with High-Dose-Rate Brachytherapy for Large Prostate Volumes

    PubMed Central

    Yang, George; Strom, Tobin J.; Wilder, Richard B.; Shrinath, Kushagra; Mellon, Eric A.; Fernandez, Daniel C.; Biagioli, Matthew C.

    2015-01-01

    ABSTRACT Purpose To evaluate dosimetric coverage of the prostate, normal tissue sparing, and acute toxicity with HDR brachytherapy for large prostate volumes. Materials and Methods One hundred and two prostate cancer patients with prostate volumes >50 mL (range: 5-29 mL) were treated with high-dose-rate (HDR) brachytherapy ± intensity modulated radiation therapy (IMRT) to 4,500 cGy in 25 daily fractions between 2009 and 2013. HDR brachytherapy monotherapy doses consisted of two 1,350-1,400 cGy fractions separated by 2-3 weeks, and HDR brachytherapy boost doses consisted of two 950-1,150 cGy fractions separated by 4 weeks. Twelve of 32 (38%) unfavorable intermediate risk, high risk, and very high risk patients received androgen deprivation therapy. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4. Results Median follow-up was 14 months. Dosimetric goals were achieved in over 90% of cases. Three of 102 (3%) patients developed Grade 2 acute proctitis. No variables were significantly associated with Grade 2 acute proctitis. Seventeen of 102 (17%) patients developed Grade 2 acute urinary retention. American Urological Association (AUA) symptom score was the only variable significantly associated with Grade 2 acute urinary retention (p=0.04). There was no ≥ Grade 3 acute toxicity. Conclusions Dosimetric coverage of the prostate and normal tissue sparing were adequate in patients with prostate volumes >50 mL. Higher pre-treatment AUA symptom scores increased the relative risk of Grade 2 acute urinary retention. However, the overall incidence of acute toxicity was acceptable in patients with large prostate volumes. PMID:26200536

  19. Inhibition of clot formation in deterministic lateral displacement arrays for processing large volumes of blood for rare cell capture.

    PubMed

    D'Silva, Joseph; Austin, Robert H; Sturm, James C

    2015-05-21

    Microfluidic deterministic lateral displacement (DLD) arrays have been applied for fractionation and analysis of cells in quantities of ~100 μL of blood, with processing of larger quantities limited by clogging in the chip. In this paper, we (i) demonstrate that this clogging phenomenon is due to conventional platelet-driven clot formation, (ii) identify and inhibit the two dominant biological mechanisms driving this process, and (iii) characterize how further reductions in clot formation can be achieved through higher flow rates and blood dilution. Following from these three advances, we demonstrate processing of 14 mL equivalent volume of undiluted whole blood through a single DLD array in 38 minutes to harvest PC3 cancer cells with ~86% yield. It is possible to fit more than 10 such DLD arrays on a single chip, which would then provide the capability to process well over 100 mL of undiluted whole blood on a single chip in less than one hour.

  20. Large Deployable Reflector (LDR) system concept and technology definition study. Volume 2: Technology assessment and technology development plan

    NASA Astrophysics Data System (ADS)

    Agnew, Donald L.; Jones, Peter A.

    1989-04-01

    A study was conducted to define reasonable and representative LDR system concepts for the purpose of defining a technology development program aimed at providing the requisite technological capability necessary to start LDR development by the end of 1991. This volume presents thirteen technology assessments and technology development plans, as well as an overview and summary of the LDR concepts. Twenty-two proposed augmentation projects are described (selected from more than 30 candidates). The five LDR technology areas most in need of supplementary support are: cryogenic cooling; astronaut assembly of the optically precise LDR in space; active segmented primary mirror; dynamic structural control; and primary mirror contamination control. Three broad, time-phased, five-year programs were synthesized from the 22 projects, scheduled, and funding requirements estimated.

  1. Large Deployable Reflector (LDR) system concept and technology definition study. Volume 2: Technology assessment and technology development plan

    NASA Technical Reports Server (NTRS)

    Agnew, Donald L.; Jones, Peter A.

    1989-01-01

    A study was conducted to define reasonable and representative LDR system concepts for the purpose of defining a technology development program aimed at providing the requisite technological capability necessary to start LDR development by the end of 1991. This volume presents thirteen technology assessments and technology development plans, as well as an overview and summary of the LDR concepts. Twenty-two proposed augmentation projects are described (selected from more than 30 candidates). The five LDR technology areas most in need of supplementary support are: cryogenic cooling; astronaut assembly of the optically precise LDR in space; active segmented primary mirror; dynamic structural control; and primary mirror contamination control. Three broad, time-phased, five-year programs were synthesized from the 22 projects, scheduled, and funding requirements estimated.

  2. A novel optical microscope for imaging large embryos and tissue volumes with sub-cellular resolution throughout

    PubMed Central

    McConnell, Gail; Trägårdh, Johanna; Amor, Rumelo; Dempster, John; Reid, Es; Amos, William Bradshaw

    2016-01-01

    Current optical microscope objectives of low magnification have low numerical aperture and therefore have too little depth resolution and discrimination to perform well in confocal and nonlinear microscopy. This is a serious limitation in important areas, including the phenotypic screening of human genes in transgenic mice by study of embryos undergoing advanced organogenesis. We have built an optical lens system for 3D imaging of objects up to 6 mm wide and 3 mm thick with depth resolution of only a few microns instead of the tens of microns currently attained, allowing sub-cellular detail to be resolved throughout the volume. We present this lens, called the Mesolens, with performance data and images from biological specimens including confocal images of whole fixed and intact fluorescently-stained 12.5-day old mouse embryos. DOI: http://dx.doi.org/10.7554/eLife.18659.001 PMID:27661778

  3. Assessing the Feasibility of Large-Scale Countercyclical Job-Creation. Final Report, Volume I, Overview and Summary.

    ERIC Educational Resources Information Center

    Urban Inst., Washington, DC.

    The feasibility of large-scale, countercyclical public job-creation was assessed. Focus was on how many job-creating activities could be undertaken as well as the job-creation potential and costs of these activities. Data was collected through field visits made to Washington-based federal government and national organizations and to twenty-four…

  4. BROAD SPECTRUM ANALYSIS FOR TRACE ORGANIC POLLUTANTS IN LARGE VOLUMES OF WATER BY XAD RESINS-COLUMN DESIGN-FACTS AND MYTHS.

    USGS Publications Warehouse

    Gibs, J.; Wicklund, A.; Suffet, I.H.

    1986-01-01

    The 'rule of thumb' that large volumes of water can be sampled for trace organic pollutants by XAD resin columns which are designed by small column laboratory studies or pure compounds is examined and shown to be a problem. A theory of multicomponent breakthrough is presented as a frame of reference to help solve the problem and develop useable criteria to aid the design of resin columns. An important part of the theory is the effect of humic substances on the breakthrough character of multicomponent chemical systems.

  5. Sensitive and Rapid Detection of Viable Giardia Cysts and Cryptosporidium parvum Oocysts in Large-Volume Water Samples with Wound Fiberglass Cartridge Filters and Reverse Transcription-PCR

    PubMed Central

    Kaucner, Christine; Stinear, Timothy

    1998-01-01

    We recently described a reverse transcription-PCR (RT-PCR) for detecting low numbers of viable Cryptosporidium parvum oocysts spiked into clarified environmental water concentrates. We have now modified the assay for direct analysis of primary sample concentrates with simultaneous detection of viable C. parvum oocysts, Giardia cysts, and a novel type of internal positive control (IPC). The IPC was designed to assess both efficiency of mRNA isolation and potential RT-PCR inhibition. Sensitivity testing showed that low numbers of organisms, in the range of a single viable cyst and oocyst, could be detected when spiked into 100-μl packed pellet volumes of concentrates from creek and river water samples. The RT-PCR was compared with an immunofluorescence (IF) assay by analyzing 29 nonspiked environmental water samples. Sample volumes of 20 to 1,500 liters were concentrated with a wound fiberglass cartridge filter. Frequency of detection for viable Giardia cysts increased from 24% by IF microscopy to 69% by RT-PCR. Viable C. parvum oocysts were detected only once by RT-PCR (3%) in contrast to detection of viable Cryptosporidium spp. in four samples by IF microscopy (14%), suggesting that Cryptosporidium species other than C. parvum were present in the water. This combination of the large-volume sampling method with RT-PCR represents a significant advance in terms of protozoan pathogen monitoring and in the wider application of PCR technology to this field of microbiology. PMID:9572946

  6. Kinetics of standardized large volume leukapheresis (LVL) in patients do not show a recruitment phenomenon of peripheral blood progenitor cells (PBPC).

    PubMed

    Cassens, U; Momkvist, P H; Zuehlsdorf, M; Mohr, M; Kienast, J; Berdel, W E; Sibrowski, W

    2001-07-01

    Although several studies have demonstrated the efficacy of large volume leukapheresis (LVL) to yield high numbers of peripheral blood progenitor cells (PBPC), the mechanisms of stem cell release into circulation and the postulated phenomenon of PBPC recruitment during apheresis have not been investigated in detail. Therefore, we analyzed the kinetics of stem cell enrichment in a total of 34 standardized LVL for patients with hematologic malignancies (lymphoma, multiple myeloma) and solid tumors (breast cancer, rhabdomyosarcoma). LVL was started 2 h after administration of G-CSF processing six times the patient's blood volume. Cells were sequentially collected into six bags and the numbers of leukocytes, mononuclear cells (MNC), CD34+ cells and colony-forming cells (CFU-GM) in each collection bag were analyzed. The numbers of PBPC collected demonstrated a continuous decrease starting after an early maximum during the second processed blood volume (P = 0.001). Interestingly, these kinetics of decreasing stem cell yields during LVL were similar for both entities of patients with hematologic malignancies as well as for both groups of patients with solid tumors. In summary, a recruitment phenomenon, defined as a time-dependent and LVL-induced increase of PBPC, could not be demonstrated in any of the diseases investigated.

  7. Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-Like Shale Oil

    SciTech Connect

    Burnham, A K

    2003-08-20

    A process is proposed to convert oil shale by radio frequency heating over a period of months to years to create a product similar to natural petroleum. Electrodes would be placed in drill holes, either vertical or horizontal, and a radio frequency chosen so that the penetration depth of the radio waves is of the order of tens to hundreds of meters. A combination of excess volume production and overburden compaction drives the oil and gas from the shale into the drill holes, where it is pumped to the surface. Electrical energy for the process could be provided initially by excess regional capacity, especially off-peak power, which would generate {approx}3 x 10{sup 5} bbl/day of synthetic crude oil, depending on shale grade. The electricity cost, using conservative efficiency assumptions, is $4.70 to $6.30/bbl, depending on grade and heating rate. At steady state, co-produced gas can generate more than half the electric power needed for the process, with the fraction depending on oil shale grade. This would increase production to 7.3 x 10{sup 5} bbl/day for 104 l/Mg shale and 1.6 x 10{sup 6} bbl/day for 146 l/Mg shale using a combination of off-peak power and power from co-produced gas.

  8. MIDAS, prototype Multivariate Interactive Digital Analysis System for large area earth resources surveys. Volume 1: System description

    NASA Technical Reports Server (NTRS)

    Christenson, D.; Gordon, M.; Kistler, R.; Kriegler, F.; Lampert, S.; Marshall, R.; Mclaughlin, R.

    1977-01-01

    A third-generation, fast, low cost, multispectral recognition system (MIDAS) able to keep pace with the large quantity and high rates of data acquisition from large regions with present and projected sensots is described. The program can process a complete ERTS frame in forty seconds and provide a color map of sixteen constituent categories in a few minutes. A principle objective of the MIDAS program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The hardware and software generated in the overall program is described. The system contains a midi-computer to control the various high speed processing elements in the data path, a preprocessor to condition data, and a classifier which implements an all digital prototype multivariate Gaussian maximum likelihood or a Bayesian decision algorithm. Sufficient software was developed to perform signature extraction, control the preprocessor, compute classifier coefficients, control the classifier operation, operate the color display and printer, and diagnose operation.

  9. Ultrafast, sensitive and large-volume on-chip real-time PCR for the molecular diagnosis of bacterial and viral infections.

    PubMed

    Houssin, Timothée; Cramer, Jérémy; Grojsman, Rébecca; Bellahsene, Lyes; Colas, Guillaume; Moulet, Hélène; Minnella, Walter; Pannetier, Christophe; Leberre, Maël; Plecis, Adrien; Chen, Yong

    2016-04-21

    To control future infectious disease outbreaks, like the 2014 Ebola epidemic, it is necessary to develop ultrafast molecular assays enabling rapid and sensitive diagnoses. To that end, several ultrafast real-time PCR systems have been previously developed, but they present issues that hinder their wide adoption, notably regarding their sensitivity and detection volume. An ultrafast, sensitive and large-volume real-time PCR system based on microfluidic thermalization is presented herein. The method is based on the circulation of pre-heated liquids in a microfluidic chip that thermalize the PCR chamber by diffusion and ultrafast flow switches. The system can achieve up to 30 real-time PCR cycles in around 2 minutes, which makes it the fastest PCR thermalization system for regular sample volume to the best of our knowledge. After biochemical optimization, anthrax and Ebola simulating agents could be respectively detected by a real-time PCR in 7 minutes and a reverse transcription real-time PCR in 7.5 minutes. These detections are respectively 6.4 and 7.2 times faster than with an off-the-shelf apparatus, while conserving real-time PCR sample volume, efficiency, selectivity and sensitivity. The high-speed thermalization also enabled us to perform sharp melting curve analyses in only 20 s and to discriminate amplicons of different lengths by rapid real-time PCR. This real-time PCR microfluidic thermalization system is cost-effective, versatile and can be then further developed for point-of-care, multiplexed, ultrafast and highly sensitive molecular diagnoses of bacterial and viral diseases.

  10. Large volumes of rejuvenated volcanism in Samoa: Evidence supporting a tectonic influence on late-stage volcanism

    NASA Astrophysics Data System (ADS)

    Konter, Jasper G.; Jackson, Matthew G.

    2012-06-01

    Hot spot volcanoes are commonly constructed in a characteristic sequence of stages. After the volumetrically dominant shield stage, a protracted period of quiescence ends with a final stage of activity: rejuvenated volcanism. The mechanism responsible for generating rejuvenated volcanism is not generally agreed upon. New data obtained for samples 200 m down-section in a deeply incised canyon on Savai`i (Samoa) are unusually enriched isotopically and indicate a relatively voluminous rejuvenated stage compared to other intraplate volcanoes. Using a modified flexural model originally proposed for Hawai`i, we suggest that the location of Samoa near the Tonga Trench terminus causes plate flexure resulting in upward flow of the shallow mantle driving partial melting. In particular, subduction-related plate bending in the Samoan region may cause a larger flexural amplitude than generated by volcanic loading in Hawai`i. The larger amplitude may explain the larger volume of rejuvenated melt in Samoa, constrained by our new data. Moreover, we argue that Sr-Nd-Pb-Os-He-Ne isotopes in Samoan rejuvenated lavas are all consistent with sampling of a lithospheric component that is characterized by a metasomatic imprint from the Pacific Plate's earlier passage over the Rarotonga hot spot. Furthermore, temperature estimates for the melts suggest a drop in temperature during the predicted shallower melting due to flexural uplift, compared to the conditions during shield volcanism. Thus, flexural bending and metasomatism of the Samoan lithosphere may have generated the voluminous and geochemically distinct Samoan rejuvenated lavas, implying the lithosphere may play an important role during this stage in non- Hawaiian hot spots.

  11. Automated Transmission-Mode Scanning Electron Microscopy (tSEM) for Large Volume Analysis at Nanoscale Resolution

    PubMed Central

    Kuwajima, Masaaki; Mendenhall, John M.; Lindsey, Laurence F.; Harris, Kristen M.

    2013-01-01

    Transmission-mode scanning electron microscopy (tSEM) on a field emission SEM platform was developed for efficient and cost-effective imaging of circuit-scale volumes from brain at nanoscale resolution. Image area was maximized while optimizing the resolution and dynamic range necessary for discriminating key subcellular structures, such as small axonal, dendritic and glial processes, synapses, smooth endoplasmic reticulum, vesicles, microtubules, polyribosomes, and endosomes which are critical for neuronal function. Individual image fields from the tSEM system were up to 4,295 µm2 (65.54 µm per side) at 2 nm pixel size, contrasting with image fields from a modern transmission electron microscope (TEM) system, which were only 66.59 µm2 (8.160 µm per side) at the same pixel size. The tSEM produced outstanding images and had reduced distortion and drift relative to TEM. Automated stage and scan control in tSEM easily provided unattended serial section imaging and montaging. Lens and scan properties on both TEM and SEM platforms revealed no significant nonlinear distortions within a central field of ∼100 µm2 and produced near-perfect image registration across serial sections using the computational elastic alignment tool in Fiji/TrakEM2 software, and reliable geometric measurements from RECONSTRUCT™ or Fiji/TrakEM2 software. Axial resolution limits the analysis of small structures contained within a section (∼45 nm). Since this new tSEM is non-destructive, objects within a section can be explored at finer axial resolution in TEM tomography with current methods. Future development of tSEM tomography promises thinner axial resolution producing nearly isotropic voxels and should provide within-section analyses of structures without changing platforms. Brain was the test system given our interest in synaptic connectivity and plasticity; however, the new tSEM system is readily applicable to other biological systems. PMID:23555711

  12. Long-range and wide field of view optical coherence tomography for in vivo 3D imaging of large volume object based on akinetic programmable swept source

    PubMed Central

    Song, Shaozhen; Xu, Jingjiang; Wang, Ruikang K.

    2016-01-01

    Current optical coherence tomography (OCT) imaging suffers from short ranging distance and narrow imaging field of view (FOV). There is growing interest in searching for solutions to these limitations in order to expand further in vivo OCT applications. This paper describes a solution where we utilize an akinetic swept source for OCT implementation to enable ~10 cm ranging distance, associated with the use of a wide-angle camera lens in the sample arm to provide a FOV of ~20 x 20 cm2. The akinetic swept source operates at 1300 nm central wavelength with a bandwidth of 100 nm. We propose an adaptive calibration procedure to the programmable akinetic light source so that the sensitivity of the OCT system over ~10 cm ranging distance is substantially improved for imaging of large volume samples. We demonstrate the proposed swept source OCT system for in vivo imaging of entire human hands and faces with an unprecedented FOV (up to 400 cm2). The capability of large-volume OCT imaging with ultra-long ranging and ultra-wide FOV is expected to bring new opportunities for in vivo biomedical applications. PMID:27896012

  13. The consequences of metric production for small manufacturers. Volume 2: Case studies of large business-small business interactions

    NASA Astrophysics Data System (ADS)

    Hitchcock, H. H.; Coates, J. F.; Canavan, M. M.; Prillaman, G. H.; Nettles, M. S.

    1982-02-01

    Over the last decade, controversy, concern, and conjecture have surrounded the effects of metric conversion on small business. Enthusiasts for metric argue that conversion would benefit small businesses in two ways. It would expand their markets, especially export markets. It would also improve business by making production processes more rational. Dissenters argue that conversion is unnecessary and possibly harmful to the majority of the nation's small businesses. Against this backdrop, the U.S. Metric Board is fulfilling its statutory mission to find out what happens to small businesses that convert to metric. The first phase of the project was a search for small businesses that had made substantial investments in converting to metric. That search showed that small businesses were most likely to invest in metric production in response to large corporations' needs for metric parts and products. The second phase of the research consisted of three case studies of the effects of large companies' conversion on small business suppliers. The team studied how the conversion of a General Electric Company department, two Ford Motor Company product lines, and three divisions of Ingersoll-Rand affected their small business suppliers.

  14. A biomechanical perspective on the role of large stem volume and high water content in baobab trees (Adansonia spp.; Bombacaceae).

    PubMed

    Chapotin, Saharah Moon; Razanameharizaka, Juvet H; Holbrook, N Michele

    2006-09-01

    The stems of large trees serve in transport, storage, and support; however, the degree to which these roles are reflected in their morphology is not always apparent. The large, water-filled stems of baobab trees (Adansonia spp.) are generally assumed to serve a water storage function, yet recent studies indicate limited use of stored water. Through an analysis of wood structure and composition, we examined whether baobab morphology reflects biomechanical constraints rather than water storage capacity in the six Madagascar baobab species. Baobab wood has a high water content (up to 79%), low wood density (0.09-0.17 g · cm(-3)), high parenchyma content (69-88%), and living cells beyond 35 cm into the xylem from the cambium. Volumetric construction cost of the wood is several times lower than in more typical trees, and the elastic modulus approaches that of parenchyma tissue. Safety factors calculated from estimated elastic buckling heights were low, indicating that baobabs are not more overbuilt than other temperate and tropical trees, yet the energy investment in stem material is comparable to that in temperate deciduous trees. Furthermore, the elastic modulus of the wood decreases with water content, such that excessive water withdrawal from the stem could affect mechanical stability.

  15. Experimental study of the response of CZT and CdTe detectors of various thicknesses in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Tan, J. W.; Cai, L.; Meng, L. J.

    2011-10-01

    In this paper, we used a combined experimental and Monte Carlo simulation approach to investigate the detailed charge collection process within thick CdTe/CZT detectors operated inside a strong magnetic field. As one of the key objectives, we quantitatively assessed the effect of the Lorenz force on the migration of charge carriers inside the detector bulk. This information would allow an accurate modeling of the detector's response to gamma ray interactions and therefore help to compensate for the event-positioning error induced by the strong magnetic field. In this study, a pixilated ERPC detector with 350 μm square pixels was set on a non-magnetic gantry and operated inside a 3 T Siemens MRI scanner. Multiple studies, with similar geometries, were performed using the same detector setup with and without the presence of the magnetic field to investigate the effect on the charge collection behavior from the strong magnetic field. The experimental results were used to validate the Monte Carlo simulation package that models both photon transportation and charge collection process inside the detector.

  16. Characteristics of a multichannel low-noise front-end ASIC for CZT-based small animal PET imaging

    NASA Astrophysics Data System (ADS)

    Gao, W.; Liu, H.; Gan, B.; Hu, Y.

    2014-05-01

    In this paper, we present the design and characteristics of a novel low-noise front-end readout application-specific integrated circuit dedicated to CdZnTe (CZT) detectors for a small animal PET imaging system. A low-noise readout method based on the charge integration and the delayed peak detection is proposed. An eight-channel front-end readout prototype chip is designed and implemented in a 0.35 μm CMOS process. The die size is 2.3 mm ×2.3 mm. The prototype chip is tested in different methods including electronic test, energy spectrum test and irradiation test. The input range of the ASIC is from 2000e- to 180,000e-, reflecting the energy of the gamma ray from 11.2 keV to 1 MeV. The gain of the readout channel is 65 mV/fC at the shaping time of 1 μs. The best test result of the equivalent noise charge (ENC) is 58.9 e- at zero farad plus 5.4 e- per picofarad. The nonlinearity and the crosstalk are less than 3% and less than 2%, respectively, at the room temperature. The static power dissipation is about 3 mW/channel.

  17. Determination of nifuroxazide in biological fluids by automated high-performance liquid chromatography with large-volume injection.

    PubMed

    Guinebault, P R; Broquaire, M; Braithwaite, R A

    1981-01-16

    A high-performance liquid chromatographic method for the measurement of nifuroxazide in plasma is described. The technique is based on the single extraction of the drug from buffered plasma with chloroform, using nifuratel as internal standard. The chromatographic system consisted of a 15 cm x 4.6 mm I.D. stainless-steel column packed with Spherisorb ODS, 5 micrometer, and the mobile phase was acetonitrile-orthophosphoric acid (pH 2.5) (30:70). The method was able to measure accurately plasma nifuroxazide concentrations down to 2 ng . ml-1 using 2 ml of sample with no interference from endogenous compounds. The coefficients of variation of the method at 200 and 2 ng . ml-1 were 3% and 15%, respectively, and the calibration graph was linear in this range. The use of automatic injection makes the method suitable for the routine analysis of large numbers of samples.

  18. Extension of an explicit finite volume method to large time steps (CFL>1): application to shallow water flows

    NASA Astrophysics Data System (ADS)

    Murillo, J.; García-Navarro, P.; Brufau, P.; Burguete, J.

    2006-01-01

    In this work, the explicit first order upwind scheme is presented under a formalism that enables the extension of the methodology to large time steps. The number of cells in the stencil of the numerical scheme is related to the allowable size of the CFL number for numerical stability. It is shown how to increase both at the same time. The basic idea is proposed for a 1D scalar equation and extended to 1D and 2D non-linear systems with source terms. The importance of the kind of grid used is highlighted and the method is outlined for irregular grids. The good quality of the results is illustrated by means of several examples including shallow water flow test cases. The bed slope source terms are involved in the method through an upwind discretization.

  19. JUICE: a data management system that facilitates the analysis of large volumes of information in an EST project workflow

    PubMed Central

    Latorre, Mariano; Silva, Herman; Saba, Juan; Guziolowski, Carito; Vizoso, Paula; Martinez, Veronica; Maldonado, Jonathan; Morales, Andrea; Caroca, Rodrigo; Cambiazo, Veronica; Campos-Vargas, Reinaldo; Gonzalez, Mauricio; Orellana, Ariel; Retamales, Julio; Meisel, Lee A

    2006-01-01

    Background Expressed sequence tag (EST) analyses provide a rapid and economical means to identify candidate genes that may be involved in a particular biological process. These ESTs are useful in many Functional Genomics studies. However, the large quantity and complexity of the data generated during an EST sequencing project can make the analysis of this information a daunting task. Results In an attempt to make this task friendlier, we have developed JUICE, an open source data management system (Apache + PHP + MySQL on Linux), which enables the user to easily upload, organize, visualize and search the different types of data generated in an EST project pipeline. In contrast to other systems, the JUICE data management system allows a branched pipeline to be established, modified and expanded, during the course of an EST project. The web interfaces and tools in JUICE enable the users to visualize the information in a graphical, user-friendly manner. The user may browse or search for sequences and/or sequence information within all the branches of the pipeline. The user can search using terms associated with the sequence name, annotation or other characteristics stored in JUICE and associated with sequences or sequence groups. Groups of sequences can be created by the user, stored in a clipboard and/or downloaded for further analyses. Different user profiles restrict the access of each user depending upon their role in the project. The user may have access exclusively to visualize sequence information, access to annotate sequences and sequence information, or administrative access. Conclusion JUICE is an open source data management system that has been developed to aid users in organizing and analyzing the large amount of data generated in an EST Project workflow. JUICE has been used in one of the first functional genomics projects in Chile, entitled "Functional Genomics in nectarines: Platform to potentiate the competitiveness of Chile in fruit exportation

  20. Environmental Monitoring and Characterization of Radiation Sources on UF Campus Using a Large Volume NaI Detector

    NASA Astrophysics Data System (ADS)

    Bruner, Jesse A.; Gardiner, Hannah E.; Jordan, Kelly A.; Baciak, James E.

    2016-09-01

    Environmental radiation surveys are important for applications such as safety and regulations. This is especially true for areas exposed to emissions from nuclear reactors, such as the University of Florida Training Reactor (UFTR). At the University of Florida, surveys are performed using the RSX-1 NaI detector, developed by Radiation Solutions Inc. The detector uses incoming gamma rays and an Advanced Digital Spectrometer module to produce a linear energy spectrum. These spectra can then be analyzed in real time with a personal computer using the built in software, RadAssist. We report on radiation levels around the University of Florida campus using two mobile detection platforms, car-borne and cart-borne. The car-borne surveys provide a larger, broader map of campus radiation levels. On the other hand, cart-borne surveys provide a more detailed radiation map because of its ability to reach places on campus cars cannot go. Throughout the survey data, there are consistent radon decay product energy peaks in addition to other sources such as medical I-131 found in a large crowd of people. Finally, we investigate further applications of this mobile detection platform, such as tracking the Ar-41 plume emitted from the UFTR and detection of potential environmental hazards.

  1. Growth and stability of stress corrosion cracks in large-diameter BWR piping. Volume 2: appendixes. Final report

    SciTech Connect

    Hale, D A; Heald, J D; Horn, R M; Jewett, C W; Kass, J N; Mehta, H S; Ranganath, S; Sharma, S R

    1982-07-01

    This report presents the results of a research program conducted to evaluate the behavior of hypothetical stress corrosion cracks in large diameter austenitic piping. The program included major tasks, a design margin assessment, an evaluation of crack growth and crack arrest, and development of a predictive model. As part of the margin assessment, the program developed diagrams which predicted net section collapse as a function of crack size. In addition, plasticity and dynamic load effects were also considered in evaluating collapse. Analytical methods for evaluating these effects were developed and were benchmarked by dynamic tests of 4-in.-diameter piping. The task of evaluating the growth behavior of stress corrosion cracks focused on developing constant load and cyclic growth rate data that could be used with the predictive model. Secondly, laboratory tests were performed to evaluate the conditions under which growing stress corrosion cracks would arrest when they intersected stress corrosion resistant weld metal. The third task successfully developed a model to predict the behavior of cracks in austenitic piping.

  2. Pre-column dilution large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of multi-class pesticides in cabbages.

    PubMed

    Zhong, Qisheng; Shen, Lingling; Liu, Jiaqi; Yu, Dianbao; Li, Siming; Yao, Jinting; Zhan, Song; Huang, Taohong; Hashi, Yuki; Kawano, Shin-ichi; Liu, Zhaofeng; Zhou, Ting

    2016-04-15

    Pre-column dilution large volume injection (PD-LVI), a novel sample injection technique for reverse phase ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), was developed in this study. The PD-LVI UHPLC-MS/MS system was designed by slightly modifying the commercial UHPLC-MS/MS equipment with a mixer chamber. During the procedure of PD-LVI, sample solution of 200μL was directly carried by the organic mobile phase to the mixer and diluted with the aqueous mobile phase. After the mixture was introduced to the UHPLC column in a mobile phase of acetonitrile-water (15/85, v/v), the target analytes were stacked on the head of the column until following separation. Using QuEChERS extraction, no additional steps such as solvent evaporation or residue redissolution were needed before injection. The features of PD-LVI UHPLC-MS/MS system were systematically investigated, including the injection volume, the mixer volume, the precondition time and the gradient elution. The efficiency of this approach was demonstrated by direct analysis of 24 pesticides in cabbages. Under the optimized conditions, low limits of detection (0.00074-0.8 ng/kg) were obtained. The recoveries were in the range of 63.3-109% with relative standard deviations less than 8.1%. Compared with common UHPLC-MS/MS technique, PD-LVI UHPLC-MS/MS showed significant advantages such as excellent sensitivity and reliability. The mechanism of PD-LVI was demonstrated to be based on the column-head stacking effect with pre-column dilution. Based on the results, PD-LVI as a simple and effective sample injection technique of reverse phase UHPLC-MS/MS for the analysis of trace analytes in complex samples showed a great promising prospect.

  3. Enhanced detection of nitroaromatic explosive vapors combining solid-phase extraction-air sampling, supercritical fluid extraction, and large-volume injection-GC.

    PubMed

    Batlle, Ramón; Carlsson, Håkan; Tollbäck, Petter; Colmsjö, Anders; Crescenzi, Carlo

    2003-07-01

    A complete method for sampling and analyzing of energetic compounds in the atmosphere is described. The method consists of the hyphenation of several techniques: active air sampling using a solid-phase extraction cartridge to collect the analytes, extraction of the sorbed analytes by toluene/methyl tert-butyl ether modified supercritical fluid extraction (SFE), and analysis of the extract by large-volume injection GC-nitrogen/phosphorus detection. The GC system is equipped with a loop-type injection interface with an early solvent vapor exit, a utilizing concurrent solvent evaporation technique. Chemometric approaches, based on a Plackett-Burman screening design and a central composite design for response surface modeling, were used to determine the optimum SFE conditions. The relative standard deviations of the optimized method were determined to be 4.3 to 7.7%, giving raise to method detection limits ranging from 0.06 to 0.36 ng in the sampling cartridge, equivalent to 6.2-36.4 pg/L in the atmosphere, standard sampling volume 10 L. The analytical method was applied to characterize headspace composition above military grade trinitrotoluene (TNT). Results confirm that 2,4-dinitrotoluene (DNT) and 1,3-dinitrobenzene (DNB) constitute the largest vapor flux, but TNT, 2,6-DNT, and trinitrobenzene TNB were also consistently detected in all the samples.

  4. Sapphire-anvil cell for small-angle neutron scattering measurements in large-volume liquid samples up to 530 MPa

    NASA Astrophysics Data System (ADS)

    Bonetti, M.; Calmettes, P.

    2005-04-01

    A cell with unsupported beveled sapphire-anvils was developed to carry out small-angle neutron scattering measurements in large-volume liquid samples up to a pressure of 530 MPa. The body of the anvil is a cylinder with a 30 mm diameter. One end is shaped into a truncated cone with a face 14 mm in diameter. The two opposed anvils squeeze a flat metallic gasket of thickness between 1 and 3 mm with a central hole between 4 and 10 mm in diameter. The initial sample volume varies from about 10 to 240mm3. The highest achievable pressure depends on the dimensions and on the mechanical properties of the gasket. To allow a high neutron transmission of the collimated neutron beam, a 10-mm-diam bore is machined along the cell axis. For a neutron beam of 7 mm in diameter, the maximum forward scattering angle is about 9.5°. With a neutron wavelength of 0.4 nm, this allows scattering spectra to be recorded for wave-number transfers up to 2.6nm-1.

  5. Development of a bar adsorptive micro-extraction-large-volume injection-gas chromatography-mass spectrometric method for pharmaceuticals and personal care products in environmental water matrices.

    PubMed

    Neng, N R; Nogueira, J M F

    2012-01-01

    The combination of bar adsorptive micro-extraction using activated carbon (AC) and polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phases, followed by liquid desorption and large-volume injection gas chromatography coupled to mass spectrometry, under selected ion monitoring mode acquisition, was developed for the first time to monitor pharmaceutical and personal care products (PPCPs) in environmental water matrices. Assays performed on 25 mL water samples spiked (100 ng L(-1)) with caffeine, gemfibrozil, triclosan, propranolol, carbamazepine and diazepam, selected as model compounds, yielded recoveries ranging from 74% to 99% under optimised experimental conditions (equilibrium time, 16 h (1,000 rpm); matrix characteristics: pH 5, 5% NaCl for AC phase; LD: methanol/acetonitrile (1:1), 45 min). The analytical performance showed good precision (RSD < 18%), convenient detection limits (5-20 ng L(-1)) and excellent linear dynamic range (20-800 ng L(-1)) with remarkable determination coefficients (r(2) > 0.99), where the PS-DVB sorbent phase showed a much better efficiency. By using the standard addition methodology, the application of the present analytical approach on tap, ground, sea, estuary and wastewater samples allowed very good performance at the trace level. The proposed method proved to be a suitable sorption-based micro-extraction alternative for the analysis of priority pollutants with medium-polar to polar characteristics, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor PPCPs in water matrices.

  6. Analysis of linear and cyclic methylsiloxanes in sewage sludges and urban soils by concurrent solvent recondensation-large volume injection-gas chromatography-mass spectrometry.

    PubMed

    Companioni-Damas, E Y; Santos, F J; Galceran, M T

    2012-12-14

    Concurrent solvent recondensation-large volume injection (CSR-LVI) is a gas chromatography injection technique that is particularly suitable for determining volatile compounds. In the present work, we evaluated the applicability of this technique for the analysis of linear and cyclic methylsiloxanes in sewage sludges and soils after solvent extraction to prevent losses of low-molecular-weight compounds. The CSR-LVI injection method was optimised to achieve maximum sensitivity and good chromatographic peak shapes. A liner packed with deactivated glass wool and a 5 m × 0.32 mm I.D. uncoated fused-silica precolumn was used. This made it possible to inject extract volumes of up to 30 μl. Good linearity (r>0.9993) and precision (RSD <15%), with recoveries ranging from 80 to 100% and method limits of quantification from 0.03 to 0.4 ng g(-1) wet weight (0.04-1.5 ng g(-1) dry weight for sewage sludges and 0.01-0.5 ng g(-1) dry weight for soils) were obtained. The developed method was applied to the analysis of linear and cyclic methylsiloxanes in sewage sludges collected from several wastewater treatment plants in Catalonia (NE Spain) and urban soils from the city of Barcelona.

  7. Quantitation of fluoride ion released sarin in red blood cell samples by gas chromatography-chemical ionization mass spectrometry using isotope dilution and large-volume injection.

    PubMed

    Jakubowski, E M; McGuire, J M; Evans, R A; Edwards, J L; Hulet, S W; Benton, B J; Forster, J S; Burnett, D C; Muse, W T; Matson, K; Crouse, C L; Mioduszewski, R J; Thomson, S A

    2004-01-01

    A new method for measuring fluoride ion released isopropyl methylphosphonofluoridate (sarin, GB) in the red blood cell fraction was developed that utilizes an autoinjector, a large-volume injector port (LVI), positive ion ammonia chemical ionization detection in the SIM mode, and a deuterated stable isotope internal standard. This method was applied to red blood cell (RBC) and plasma ethyl acetate extracts from spiked human and animal whole blood samples and from whole blood of minipigs, guinea pigs, and rats exposed by whole-body sarin inhalation. Evidence of nerve agent exposure was detected in plasma and red blood cells at low levels of exposure. The linear method range of quantitation was 10-1000 pg on-column with a detection limit of approximately 2-pg on-column. In the course of method development, several conditions were optimized for the LVI, including type of injector insert, injection volume, initial temperature, pressure, and flow rate. RBC fractions had advantages over the plasma with respect to assessing nerve agent exposure using the fluoride ion method especially in samples with low serum butyrylcholinesterase activity.

  8. Determination of pesticides in seaweeds by pressurized liquid extraction and programmed temperature vaporization-based large volume injection-gas chromatography-tandem mass spectrometry.

    PubMed

    García-Rodríguez, D; Carro-Díaz, A M; Lorenzo-Ferreira, R A; Cela-Torrijos, R

    2010-04-23

    A rapid method for the simultaneous identification and quantification of pesticide residues in edible seaweed has been developed. Target analytes were three pyrethroid, a carbamate and two organophosphorus pesticides. The procedure consists of a pressurized liquid extraction (PLE) with integrated clean-up, followed by gas chromatography coupled to tandem mass spectrometry. Five PLE parameters were investigated using a screening design: temperature, static extraction time, number of cycles, percent of flush volume and quantitative composition of the n-hexane/ethyl acetate extraction solvent. The effect of the in-cell clean-up with Florisil and graphitized carbon black adsorbents was investigated using a Doehlert response surface design. Large volumes of sample extracts were injected using a programmed-temperature vaporizer (PTV-LVI) to improve both sensitivity and selectivity of measurements. Quantification was carried by the internal standard method with surrogate deuterated standards. The method showed excellent linearity (R2>0.999) and precision (relative standard deviation, RSD < or = 8%) for all compounds, with detection limits ranging from 0.3 pg g(-1) for chlorpyrifos-ethyl, to 3.0 pg g(-1) for carbaryl (23.1 pg g(-1) for deltamethrin). Recoveries in real seaweed samples were within the range 82-108%. The method was satisfactory validated for the analysis of wild and cultivated edible seaweeds. The presence of pyrethroid and organophosphorus pesticides in some of the samples was evidenced.

  9. Microwave-assisted extraction and large-volume injection gas chromatography tandem mass spectrometry determination of multiresidue pesticides in edible seaweed.

    PubMed

    García-Rodríguez, D; Carro, A M; Cela, R; Lorenzo, R A

    2010-09-01

    A microwave-assisted extraction method followed by clean-up with solid-phase extraction (SPE) combined with large-volume injection gas chromatography-tandem mass spectrometry (LVI-GC-MS/MS) for the analysis of 17 pesticides in wild and aquaculture edible seaweeds has been developed. An experimental central composite design was employed to evaluate the effects of the main variables potentially affecting the extraction (temperature, time, and solvent volume) and to optimize the process. The most effective microwave extraction conditions were achieved at 125 °C and 12 min with 24 mL of hexane/ethyl acetate (80:20). SPE clean-up of the extracts with graphitized carbon and Florisil, optimized by means of the experimental design, proved to be efficient in the removal of matrix interferences. The analytical recoveries were close to 100% for all the analytes, with relative standard deviations lower than 13%. The limits of detection ranged from 0.3 to 23.1 pg g(-1) and the limits of quantification were between 2.3 and 76.9 pg g(-1), far below the maximum residue levels established by the European Union for pesticides in seaweed. The results obtained prove the suitability of the microwave-assisted extraction for the routine analysis of pesticides in aquaculture and wild seaweed samples.

  10. New large volume hydrothermal reaction cell for studying chemical processes under supercritical hydrothermal conditions using time-resolved in situ neutron diffraction

    NASA Astrophysics Data System (ADS)

    Ok, Kang Min; O'Hare, Dermot; Smith, Ronald I.; Chowdhury, Mohammed; Fikremariam, Hanna

    2010-12-01

    The design and testing of a new large volume Inconel pressure cell for the in situ study of supercritical hydrothermal syntheses using time-resolved neutron diffraction is introduced for the first time. The commissioning of this new cell is demonstrated by the measurement of the time-of-flight neutron diffraction pattern for TiO2 (Anatase) in supercritical D2O on the POLARIS diffractometer at the United Kingdom's pulsed spallation neutron source, ISIS, Rutherford Appleton Laboratory. The sample can be studied over a wide range of temperatures (25-450 °C) and pressures (1-355 bar). This novel apparatus will now enable us to study the kinetics and mechanisms of chemical syntheses under extreme environments such as supercritical water, and in particular to study the crystallization of a variety of technologically important inorganic materials.

  11. Large pore volume mesoporous copper particles and scaffold microporous carbon material obtained from an inorganic-organic nanohybrid material, copper-succinate-layered hydroxide.

    PubMed

    Ghotbi, Mohammad Yeganeh; Bagheri, Narjes; Sadrnezhaad, S K

    2011-10-01

    Copper-succinate-layered hydroxide (CSLH), a new nanohybrid material, was synthesized as an inorganic-organic nanohybrid, in which organic moiety was intercalated between the layers of a single cation layered material, copper hydroxide nitrate. Microporous scaffold carbon material was obtained by thermal decomposition of the nanohybrid at 500 °C under argon atmosphere followed by acid washing process. Furthermore, the heat-treated product of the nanohybrid at 600 °C was ultrafine mesoporous metallic copper particles. The results of this study confirmed the great potential of CSLH to produce the carbon material with large surface area (580 m(2)/g) and high pore volume copper powder (2.04 cm(3)/g).

  12. New large volume hydrothermal reaction cell for studying chemical processes under supercritical hydrothermal conditions using time-resolved in situ neutron diffraction.

    PubMed

    Ok, Kang Min; O'Hare, Dermot; Smith, Ronald I; Chowdhury, Mohammed; Fikremariam, Hanna

    2010-12-01

    The design and testing of a new large volume Inconel pressure cell for the in situ study of supercritical hydrothermal syntheses using time-resolved neutron diffraction is introduced for the first time. The commissioning of this new cell is demonstrated by the measurement of the time-of-flight neutron diffraction pattern for TiO(2) (Anatase) in supercritical D(2)O on the POLARIS diffractometer at the United Kingdom's pulsed spallation neutron source, ISIS, Rutherford Appleton Laboratory. The sample can be studied over a wide range of temperatures (25-450 °C) and pressures (1-355 bar). This novel apparatus will now enable us to study the kinetics and mechanisms of chemical syntheses under extreme environments such as supercritical water, and in particular to study the crystallization of a variety of technologically important inorganic materials.

  13. Determination of Atto- to Femtogram Levels of Americium and Curium Isotopes in Large-Volume Urine Samples by Compact Accelerator Mass Spectrometry.

    PubMed

    Dai, Xiongxin; Christl, Marcus; Kramer-Tremblay, Sheila; Synal, Hans-Arno

    2016-03-01

    Ultralow level analysis of actinides in urine samples may be required for dose assessment in the event of internal exposures to these radionuclides at nuclear facilities and nuclear power plants. A new bioassay method for analysis of sub-femtogram levels of Am and Cm in large-volume urine samples was developed. Americium and curium were co-precipitated with hydrous titanium oxide from the urine matrix and purified by column chromatography separation. After target preparation using mixed titanium/iron oxides, the final sample was measured by compact accelerator mass spectrometry. Urine samples spiked with known quantities of Am and Cm isotopes in the range of attogram to femtogram levels were measured for method evaluation. The results are in good agreement with the expected values, demonstrating the feasibility of compact accelerator mass spectrometry (AMS) for the determination of minor actinides at the levels of attogram/liter in urine samples to meet stringent sensitivity requirements for internal dosimetry assessment.

  14. A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance Probe for In-Situ Investigations with Constant Flow of Reactants

    SciTech Connect

    Hu, Jian Z.; Sears, Jesse A.; Mehta, Hardeep S.; Ford, Joseph J.; Kwak, Ja Hun; Zhu, Kake; Wang, Yong; Liu, Jun; Hoyt, David W.; Peden, Charles HF

    2012-02-21

    A large-sample-volume constant-flow magic angle sample spinning (CF-MAS) NMR probe is reported for in-situ studies of the reaction dynamics, stable intermediates/transition states, and mechanisms of catalytic reactions. In our approach, the reactants are introduced into the catalyst bed using a fixed tube at one end of the MAS rotor while a second fixed tube, linked to a vacuum pump, is attached at the other end of the rotor. The pressure difference between both ends of the catalyst bed inside the sample cell space forces the reactants flowing through the catalyst bed, which improves the diffusion of the reactants and products. This design allows the use of a large sample volume for enhanced sensitivity and thus permitting in-situ 13C CF-MAS studies at natural abundance. As an example of application, we show that reactants, products and reaction transition states associated with the 2-butanol dehydration reaction over a mesoporous silicalite supported heteropoly acid catalyst (HPA/meso-silicalite-1) can all be detected in a single 13C CF-MAS NMR spectrum at natural abundance. Coke products can also be detected at natural 13C abundance and under the stopped flow condition. Furthermore, 1H CF-MAS NMR is used to identify the surface functional groups of HPA/meso-silicalite-1 under the condition of in-situ drying . We also show that the reaction dynamics of 2-butanol dehydration using HPA/meso-silicalite-1 as a catalyst can be explored using 1H CF-MAS NMR.

  15. Phenocryst abundances and glass and phenocryst compositions as indicators of magmatic environments of large-volume ash flow sheets in southwestern Nevada

    SciTech Connect

    Warren, R. G.; Byers, F. M., Jr.; Broxton, D. E.; Freeman, S. H.; Hagan, R. C.

    1989-05-10

    The Topopah Spring, Tiva Canyon, Rainier Mesa, and Ammonia Tanks tuffsare large-volume, silicic ash flow sheets that provide samples of fourmagmatic systems in southwestern Nevada. Successively erupted within a span of2 m.y. from the same source area, they allow comparison of the sequentialevolution of large-volume, mature Cordilleran magmatic systems. Each largesheet has a rhyolitic lower zone and quartz latitic upper zone. Coevalbasaltic andesite and basalt show petrochemical continuity with these sheetsand may represent mantle contributions that triggered eruptions of themidcrustal silicic portion. Abundance of phenocrysts and accessory phasesincrease upward with whole rock Fe (FeOt) from the base of all four sheets tomaximum values unique for each system. Although maximum abundances of eachmineral are unique for each sheet, each maximum occupies the same relativeposition within each sheet. High-temperature minerals such as plagioclaseincrease in abundance continuously with FeOt in each system, showing a decreasewith FeOt only within basaltic andesite at the base of the Rainier Mesasystem. Late crystallizing minerals such as quartz and sphene show maximumabundances at much lower FeOt, at or near the top of the rhyolitic zone.Minerals that normally form at intermediate stages of crystallization, such assanidine, show maxima at intermediate FeOt for each sheet. A continuum ofglass and phenocryst compositions occurs within the Topopah Spring andRainier Mesa sheets. Variations in phenocryst compositions with FeOt aregenerally consistent with those expected for crystallization within magmareservoirs characterized by vertical thermal and compositional gradients.However, simple fractional crystallization does not adequately explain theclose relationship in each sheet among the mineral chemistry, glass (magma)chemistry, and phase assemblages, which indicate a close approach to equilibriumwithin each magma system.

  16. New approach to large-volume injection in reversed-phase high performance liquid chromatography: determination of atrazine and hydroxyatrazine in soil samples.

    PubMed

    Hutta, Milan; Chalányová, Mária; Halko, Radoslav; Góra, Róbert; Rybár, Ivan; Pajchl, Marek; Dokupilová, Svetlana

    2006-08-01

    A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow-rate setting accuracy of +/- 1-2% over a flow-rate range from 0.1 mL/min to 10 mL/min and the flow stability is 0.2% or less. Quarternary low pressure gradient pumps are widely available and used, but all their hydraulic lines are seldom utilised. The idea of using one line of a common commercial HPLC quaternary low-pressure pump for direct on-column injection (pumping) of large sample volumes ranging from 1 mL to 100 mL was tested. This approach was evaluated during practical work on the development of an RP-HPLC method of determination of residual atrazine and hydroxyatrazine. In lysimetric environmental experiments hydroxyatrazine was formed in situ in a soil column by hydrolysis of atrazine. The results proved the applicability of this approach not only in experiments with model mixtures of analytes at microg/L levels in solutions. Analysis of 20 mL of soil leachates and extracts of soil samples containing atrazine and hydroxyatrazine at the 10 microg/kg level (in dry soil) revealed that good figures-of-merit were preserved, even in the presence of a large excess of humic substances.

  17. LiDAR-Landsat data fusion for large-area assessment of urban land cover: Balancing spatial resolution, data volume and mapping accuracy

    NASA Astrophysics Data System (ADS)

    Singh, Kunwar K.; Vogler, John B.; Shoemaker, Douglas A.; Meentemeyer, Ross K.

    2012-11-01

    The structural characteristics of Light Detection and Ranging (LiDAR) data are increasingly used to classify urban environments at fine scales, but have been underutilized for distinguishing heterogeneous land covers over large urban regions due to high cost, limited spectral information, and the computational difficulties posed by inherently large data volumes. Here we explore tradeoffs between potential gains in mapping accuracy with computational costs by integrating structural and intensity surface models extracted from LiDAR data with Landsat Thematic Mapper (TM) imagery and evaluating the degree to which TM, LiDAR, and LiDAR-TM fusion data discriminated land covers in the rapidly urbanizing region of Charlotte, North Carolina, USA. Using supervised maximum likelihood (ML) and classification tree (CT) methods, we classified TM data at 30 m and LiDAR data and LiDAR-TM fusions at 1 m, 5 m, 10 m, 15 m and 30 m resolutions. We assessed the relative contributions of LiDAR structural and intensity surface models to classification map accuracy and identified optimal spatial resolution of LiDAR surface models for large-area assessments of urban land cover. ML classification of 1 m LiDAR-TM fusions using both structural and intensity surface models increased total accuracy by 32% compared to LiDAR alone and by 8% over TM at 30 m. Fusion data using all LiDAR surface models improved class discrimination of spectrally similar forest, farmland, and managed clearings and produced the highest total accuracies at 1 m, 5 m, and 10 m resolutions (87.2%, 86.3% and 85.4%, respectively). At all resolutions of fusion data and using either ML or CT classifier, the relative contribution of the LiDAR structural surface models (canopy height and normalized digital surface model) to classification accuracy is greater than the intensity surface. Our evaluation of tradeoffs between data volume and thematic map accuracy for this study system suggests that a spatial resolution of 5 m for Li

  18. Geochronology, geochemistry, and tectonic characterization of Quaternary large-volume travertine deposits in the southwestern United States and their implications for CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Priewisch, Alexandra

    Travertines are freshwater carbonates that precipitate from carbonic groundwater due to the degassing of CO2. Travertine deposits are often situated along faults that serve as conduits for CO2-charged groundwater and their geochemistry often records mixing of deeply-derived fluids and volatiles with shallow meteoric water. Travertines are surface expressions of dynamic mantle processes related to the tectonic setting. This dissertation includes four chapters that focus on different aspects of travertine formation and their scientific value. They are excellent, although underestimated, diagnostic tools for climatology, hydrology, tectonics, geochemistry, geomicrobiology, and they can inform carbon sequestration models. Quaternary large-volume travertine deposits in New Mexico and Arizona occur in an extensional tectonic stress regime on the southeastern Colorado Plateau and along the Rio Grande rift. They accumulated above fault systems during episodes of high hydraulic head in confined aquifers, increased regional volcanic activity, and high input of mantle-derived volatiles such as CO 2 and He. Stable isotope and trace element geochemistry of travertines is controlled by groundwater geochemistry as well as the degassing of CO 2. The geochemical composition allows for distinguishing different travertine facies and evaluating past groundwater flow. The travertine deposits in New Mexico are interpreted to be extinct CO2 fields due to the large volumes that accumulated and in analogy to the travertine deposits in Arizona that are associated with an active CO2-gas field. Travertines are natural analogues for CO2 leakage along fault systems that bypassed regional cap rocks and they provide important insight into the migration of CO2 from a reservoir to the surface. The volume of travertine can be used to infer the integrated CO2 leakage along a fault system over geologic time. This leakage is estimated as: (1) CO2 that becomes fixed in CaCO3/travertine (tons of carbon

  19. Large-volume silicic volcanism in Kamchatka: Ar-Ar and U-Pb ages, isotopic, and geochemical characteristics of major pre-Holocene caldera-forming eruptions

    NASA Astrophysics Data System (ADS)

    Bindeman, I. N.; Leonov, V. L.; Izbekov, P. E.; Ponomareva, V. V.; Watts, K. E.; Shipley, N. K.; Perepelov, A. B.; Bazanova, L. I.; Jicha, B. R.; Singer, B. S.; Schmitt, A. K.; Portnyagin, M. V.; Chen, C. H.

    2010-01-01

    The Kamchatka Peninsula in far eastern Russia represents the most volcanically active arc in the world in terms of magma production and the number of explosive eruptions. We investigate large-scale silicic volcanism in the past several million years and present new geochronologic results from major ignimbrite sheets exposed in Kamchatka. These ignimbrites are found in the vicinity of morphologically-preserved rims of partially eroded source calderas with diameters from ˜ 2 to ˜ 30 km and with estimated volumes of eruptions ranging from 10 to several hundred cubic kilometers of magma. We also identify and date two of the largest ignimbrites: Golygin Ignimbrite in southern Kamchatka (0.45 Ma), and Karymshina River Ignimbrites (1.78 Ma) in south-central Kamchatka. We present whole-rock geochemical analyses that can be used to correlate ignimbrites laterally. These large-volume ignimbrites sample a significant proportion of remelted Kamchatkan crust as constrained by the oxygen isotopes. Oxygen isotope analyses of minerals and matrix span a 3‰ range with a significant proportion of moderately low- δ18O values. This suggests that the source for these ignimbrites involved a hydrothermally-altered shallow crust, while participation of the Cretaceous siliceous basement is also evidenced by moderately elevated δ18O and Sr isotopes and xenocryst contamination in two volcanoes. The majority of dates obtained for caldera-forming eruptions coincide with glacial stages in accordance with the sediment record in the NW Pacific, suggesting an increase in explosive volcanic activity since the onset of the last glaciation 2.6 Ma. Rapid changes in ice volume during glacial times and the resulting fluctuation of glacial loading/unloading could have caused volatile saturation in shallow magma chambers and, in combination with availability of low- δ18O glacial meltwaters, increased the proportion of explosive vs effusive eruptions. The presented results provide new constraints on

  20. A Novel Front-End ASIC With Post Digital Filtering and Calibration for CZT-Based PET Detector

    SciTech Connect

    Gao, W.; Yin, J.; Li, C.; Zeng, H.; Gao, D.; Hu, Y.

    2015-07-01

    This paper presents a novel front-end electronics based on a front-end ASIC with post digital filtering and calibration dedicated to CZT detectors for PET imaging. A cascade amplifier based on split-leg topology is selected to realize the charge-sensitive amplifier (CSA) for the sake of low noise performances and the simple scheme of the power supplies. The output of the CSA is connected to a variable-gain amplifier to generate the compatible signals for the A/D conversion. A multi-channel single-slope ADC is designed to sample multiple points for the digital filtering and shaping. The digital signal processing algorithms are implemented by a FPGA. To verify the proposed scheme, a front-end readout prototype ASIC is designed and implemented in 0.35 μm CMOS process. In a single readout channel, a CSA, a VGA, a 10-bit ADC and registers are integrated. Two dummy channels, bias circuits, and time controller are also integrated. The die size is 2.0 mm x 2.1 mm. The input range of the ASIC is from 2000 e{sup -} to 100000 e{sup -}, which is suitable for the detection of the X-and gamma ray from 11.2 keV to 550 keV. The linearity of the output voltage is less than 1 %. The gain of the readout channel is 40.2 V/pC. The static power dissipation is about 10 mW/channel. The above tested results show that the electrical performances of the ASIC can well satisfy PET imaging applications. (authors)

  1. Application of large volume injection GC-MS to analysis of organic compounds in the extracts and leachates of municipal solid waste incineration fly ash

    SciTech Connect

    Korenkova, Eva; Slobodnik, Jaroslav

    2006-07-01

    Organic solvent and water extracts of fly ash from a Milan (Italy) municipal solid waste incinerator (MSWI) were analyzed by large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) with programmable temperature vaporizer (PTV). Using injection volumes of 10-100 {mu}l, typically over a hundred compounds were detected in organic solvent extracts and ca. 35% of them could be tentatively identified from their electron impact ionization mass spectra. A protocol for the determination of the maximum amount of a potential environmental pollutant available for leaching (availability test) was developed for four selected target compounds: pentachlorobenzene (PeCB), hexachlorobenzene (HxCB), o-terphenyl (o-TPH) and m-terphenyl (m-TPH). Key parameters, extraction time and liquid-to-solid ratio (L/S), were studied in more detail. Recoveries of PeCB, HxCB and o-TPH spiked into the fly ash samples at two concentration levels ranged from 38% to 53% for freshly spiked and from 14% to 40% for 40-day aged fly ash. Recoveries of m-TPH were 8% to 11% from freshly spiked and less than 3% from aged spiked fly ash. The native amounts in Milan MSWI fly ash, determined in an interlaboratory exercise using the developed protocol, were 31 ng/g PeCB, 34 ng/g HxCB, 72 ng/g o-TPH and 4.4 ng/g m-TPH. A separate methodology was developed for the determination of compounds extracted from fly ash by water (leaching test). Following 8-h sonication at L/S 20, the leached amounts of PeCB, HxCB and o-TPH were 1.1, 3.1 and 6.0 ng/g fly ash, respectively.

  2. Generation of a large volume of clinically relevant nanometre-sized ultra-high-molecular-weight polyethylene wear particles for cell culture studies.

    PubMed

    Liu, Aiqin; Ingham, Eileen; Fisher, John; Tipper, Joanne L

    2014-04-01

    It has recently been shown that the wear of ultra-high-molecular-weight polyethylene in hip and knee prostheses leads to the generation of nanometre-sized particles, in addition to micron-sized particles. The biological activity of nanometre-sized ultra-high-molecular-weight polyethylene wear particles has not, however, previously been studied due to difficulties in generating sufficient volumes of nanometre-sized ultra-high-molecular-weight polyethylene wear particles suitable for cell culture studies. In this study, wear simulation methods were investigated to generate a large volume of endotoxin-free clinically relevant nanometre-sized ultra-high-molecular-weight polyethylene wear particles. Both single-station and six-station multidirectional pin-on-plate wear simulators were used to generate ultra-high-molecular-weight polyethylene wear particles under sterile and non-sterile conditions. Microbial contamination and endotoxin levels in the lubricants were determined. The results indicated that microbial contamination was absent and endotoxin levels were low and within acceptable limits for the pharmaceutical industry, when a six-station pin-on-plate wear simulator was used to generate ultra-high-molecular-weight polyethylene wear particles in a non-sterile environment. Different pore-sized polycarbonate filters were investigated to isolate nanometre-sized ultra-high-molecular-weight polyethylene wear particles from the wear test lubricants. The use of the filter sequence of 10, 1, 0.1, 0.1 and 0.015 µm pore sizes allowed successful isolation of ultra-high-molecular-weight polyethylene wear particles with a size range of < 100 nm, which was suitable for cell culture studies.

  3. On-line liquid chromatography-mass spectrometry with dilution line to achieve large volume urine injection for the improvement of sensitivity.

    PubMed

    Liu, Min; Yan, Wei; Lin, Jin-Ming; Hashi, Yuki; Liu, Li-Bin; Wei, Yanlin

    2008-07-11

    A unique automated on-line high-performance liquid chromatography-mass spectrometry (LC-MS) method was developed allowing injection of a large volume of urine for the improvement of sensitivity using estrogens as analytes. The urine sample was precipitated by acetonitrile (sample:acetonitrile, 1:2, v/v) to remove most proteins. Then the supernatant was directly delivered at 0.3 mL/min by a pump, which broke through the limit of autosampler with fixed loop. Then the sample was loaded onto a restricted access media (RAM) pre-column after on-line dilution with NH(4)Ac solution which was delivered by another pump under high flow-rate. After the addition of on-line dilution line, the content of organic solvent in the sample aliquot was sharply decreased so that the analytes were effectively trapped by pre-column. In addition, another 6-port valve was added to selectively deliver the effluent containing analytes into MS, which minimized the pollution of the MS and matrix effect. After optimization of the condition of extraction method, 3 mL sample (containing 1 mL urine) could be successfully enriched. The injection volume increased 10 times compared with conventional on-line LC-MS methods for biofluid analysis, significantly improving sensitivity. Moreover, no obvious increase of column pressure was observed after 300 injections. The method was validated by spiking urine. Linearity was determined by sample which was in the range of 1-500 ng/mL. The process efficiency ranged from 70.2 to 106% with RSDs less than 15% with the exception of a few analytes. The limit of detection (LOD) and quantification (LOQ) ranged from 0.3 to 2 ng/mL and 1 to 8 ng/mL, respectively, corresponding a decrease of 1-2 orders of magnitude compared with those of off-line and on-line methods.

  4. Integrated strong cation-exchange hybrid monolith coupled with capillary zone electrophoresis and simultaneous dynamic pH junction for large-volume proteomic analysis by mass spectrometry.

    PubMed

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Yan, Xiaojing; Dovichi, Norman J

    2015-06-01

    A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50 µm ID capillary, a 1cm long SCX-SPE monolith, a 60cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1 µL. By loading 21 µL of a 1×10(-7) M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N=44,000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15 pmol by frontal analysis with 10(-5) M angiotensin II. The system was also applied to the analysis of a 10(-4) mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5 µL of a 10(-3) mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20 min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates.

  5. Investigation of the Relationship Between Gross Tumor Volume Location and Pneumonitis Rates Using a Large Clinical Database of Non-Small-Cell Lung Cancer Patients

    SciTech Connect

    Vinogradskiy, Yevgeniy; Tucker, Susan L.; Liao Zhongxing; Martel, Mary K.

    2012-04-01

    Purpose: Studies have suggested that function may vary throughout the lung, and that patients who have tumors located in the base of the lung are more susceptible to radiation pneumonitis. The purpose of our study was to investigate the relationship between gross tumor volume (GTV) location and pneumonitis rates using a large clinical database of 547 patients with non-small-cell lung cancer. Methods and Materials: The GTV centroids of all patients were mapped onto one common coordinate system, in which the boundaries of the coordinate system were defined by the extreme points of each individual patient lung. The data were qualitatively analyzed by graphing all centroids and displaying the data according to the presence of severe pneumonitis, tumor stage, and smoking status. The centroids were grouped according to superior-inferior segments, and the pneumonitis rates were analyzed. In addition, we incorporated the GTV centroid information into a Lyman-Kutcher-Burman normal tissue complication probability model and tested whether adding spatial information significantly improved the fit of the model. Results: Of the 547 patients analyzed, 111 (20.3%) experienced severe radiation pneumonitis. The pneumonitis incidence rates were 16%, 23%, and 21% for the superior, middle, and inferior thirds of the lung, respectively. Qualitatively, the GTV centroids of nonsmokers were notably absent from the superior portion of the lung. In addition, the GTV centroids of patients who had Stage III and IV clinical staging were concentrated toward the medial edge of the lung. The comparison between the GTV centroid model and the conventional dose-volume model did not yield a statistically significant difference in model fit. Conclusions: Lower pneumonitis rates were noted for the superior portion of the lung; however the differences were not statistically significant. For our patient cohort, incorporating GTV centroid information did not lead to a statistically significant improvement

  6. Determination of cyclic volatile methylsiloxanes in water, sediment, soil, biota, and biosolid using large-volume injection-gas chromatography-mass spectrometry.

    PubMed

    Wang, De-Gao; Alaee, Mehran; Steer, Helena; Tait, Tara; Williams, Zackery; Brimble, Samantha; Svoboda, Lewina; Barresi, Enzo; Dejong, Maryl; Schachtschneider, Joanne; Kaminski, Ed; Norwood, Warren; Sverko, Ed

    2013-10-01

    Several methods were developed to detect the cyclic volatile methylsiloxanes (cVMSs) including octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in water, sediment, soil, biota, and biosolid samples. Analytical techniques employed to optimize measurement of this compound class in various matrices included membrane-assisted solvent extraction in water, liquid-solid extraction for sediment, soil, biota, and biosolid samples. A subsequent analysis of the extract was conducted by large-volume injection-gas chromatography-mass spectrometry (LVI-GC-MS). These methods employed no evaporative techniques to avoid potential losses and contamination of the volatile siloxanes. To compensate for the inability to improve detection limits by concentrating final sample extract volumes we used a LVI-GC-MS. Contamination during analysis was minimized by using a septumless GC configuration to avoid cVMS's associated with septum bleed. These methods performed well achieving good linearity, low limits of detection, good precision, recovery, and a wide dynamic range. In addition, stability of cVMS in water and sediment was assessed under various storage conditions. D4 and D5 in Type-I (Milli-Q) water stored at 4°C were stable within 29d; however, significant depletion of D6 (60-70%) occurred only after 3d. Whereas cVMS in sewage influent and effluent were stable at 4°C within 21d. cVMS in sediment sealed in amber glass jars at -20°C and in pentane extracts in vials at -15°C were stable during 1month under both storage conditions.

  7. Origin and emplacement of the andesite of Burroughs Mountain, a zoned, large-volume lava flow at Mount Rainier, Washington, USA

    NASA Astrophysics Data System (ADS)

    Stockstill, Karen R.; Vogel, Thomas A.; Sisson, Thomas W.

    2003-01-01

    Burroughs Mountain, situated at the northeast foot of Mount Rainier, WA, exposes a large-volume (3.4 km 3) andesitic lava flow, up to 350 m thick and extending 11 km in length. Two sampling traverses from flow base to eroded top, over vertical sections of 245 and 300 m, show that the flow consists of a felsic lower unit (100 m thick) overlain sharply by a more mafic upper unit. The mafic upper unit is chemically zoned, becoming slightly more evolved upward; the lower unit is heterogeneous and unzoned. The lower unit is also more phenocryst-rich and locally contains inclusions of quenched basaltic andesite magma that are absent from the upper unit. Widespread, vuggy, gabbronorite-to-diorite inclusions may be fragments of shallow cumulates, exhumed from the Mount Rainier magmatic system. Chemically heterogeneous block-and-ash-flow deposits that conformably underlie the lava flow were the earliest products of the eruptive episode. The felsic-mafic-felsic progression in lava composition resulted from partial evacuation of a vertically-zoned magma reservoir, in which either (1) average depth of withdrawal increased, then decreased, during eruption, perhaps due to variations in effusion rate, or (2) magmatic recharge stimulated ascent of a plume that brought less evolved magma to shallow levels at an intermediate stage of the eruption. Pre-eruptive zonation resulted from combined crystallization-differentiation and intrusion(s) of less evolved magma into the partly crystallized resident magma body. The zoned lava flow at Burroughs Mountain shows that, at times, Mount Rainier's magmatic system has developed relatively large, shallow reservoirs that, despite complex recharge events, were capable of developing a felsic-upward compositional zonation similar to that inferred from large ash-flow sheets and other zoned lava flows.

  8. Origin and emplacement of the andesite of Burroughs Mountain, a zoned, large-volume lava flow at Mount Rainier, Washington, USA

    USGS Publications Warehouse

    Stockstill, K.R.; Vogel, T.A.; Sisson, T.W.

    2002-01-01

    Burroughs Mountain, situated at the northeast foot of Mount Rainier, WA, exposes a large-volume (3.4 km3) andesitic lava flow, up to 350 m thick and extending 11 km in length. Two sampling traverses from flow base to eroded top, over vertical sections of 245 and 300 m, show that the flow consists of a felsic lower unit (100 m thick) overlain sharply by a more mafic upper unit. The mafic upper unit is chemically zoned, becoming slightly more evolved upward; the lower unit is heterogeneous and unzoned. The lower unit is also more phenocryst-rich and locally contains inclusions of quenched basaltic andesite magma that are absent from the upper unit. Widespread, vuggy, gabbronorite-to-diorite inclusions may be fragments of shallow cumulates, exhumed from the Mount Rainier magmatic system. Chemically heterogeneous block-and-ash-flow deposits that conformably underlie the lava flow were the earliest products of the eruptive episode. The felsic-mafic-felsic progression in lava composition resulted from partial evacuation of a vertically-zoned magma reservoir, in which either (1) average depth of withdrawal increased, then decreased, during eruption, perhaps due to variations in effusion rate, or (2) magmatic recharge stimulated ascent of a plume that brought less evolved magma to shallow levels at an intermediate stage of the eruption. Pre-eruptive zonation resulted from combined crystallization- differentiation and intrusion(s) of less evolved magma into the partly crystallized resident magma body. The zoned lava flow at Burroughs Mountain shows that, at times, Mount Rainier's magmatic system has developed relatively large, shallow reservoirs that, despite complex recharge events, were capable of developing a felsic-upward compositional zonation similar to that inferred from large ash-flow sheets and other zoned lava flows. ?? 2002 Elsevier Science B.V. All rights reserved.

  9. A dosimetric comparison of 3D-CRT, IMRT, and static tomotherapy with an SIB for large and small breast volumes

    SciTech Connect

    Michalski, Andrea; Atyeo, John; Cox, Jennifer; Rinks, Marianne; Morgia, Marita; Lamoury, Gillian

    2014-07-01

    Radiation therapy to the breast is a complex task, with many different techniques that can be employed to ensure adequate dose target coverage while minimizing doses to the organs at risk. This study compares the dose planning outcomes of 3 radiation treatment modalities, 3 dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and static tomotherapy, for left-sided whole-breast radiation treatment with a simultaneous integrated boost (SIB). Overall, 20 patients with left-sided breast cancer were separated into 2 cohorts, small and large, based on breast volume. Dose plans were produced for each patient using 3D-CRT, IMRT, and static tomotherapy. All patients were prescribed a dose of 45 Gy in 20 fractions to the breast with an SIB of 56 Gy in 20 fractions to the tumor bed and normalized so that D{sub 98%} > 95% of the prescription dose. Dosimetric comparisons were made between the 3 modalities and the interaction of patient size. All 3 modalities offered adequate planning target volume (PTV) coverage with D{sub 98%} > 95% and D{sub 2%} < 107%. Static tomotherapy offered significantly improved (p = 0.006) dose homogeneity to the PTV{sub boost} {sub eval} (0.079 ± 0.011) and breast minus the SIB volume (Breast{sub SIB}) (p < 0.001, 0.15 ± 0.03) compared with the PTV{sub boost} {sub eval} (0.085 ± 0.008, 0.088 ± 0.12) and Breast{sub SIB} (0.22 ± 0.05, 0.23 ± 0.03) for IMRT and 3D-CRT, respectively. Static tomotherapy also offered statistically significant reductions (p < 0.001) in doses to the ipsilateral lung mean dose of 6.79 ± 2.11 Gy compared with 7.75 ± 2.54 Gy and 8.29 ± 2.76 Gy for IMRT and 3D-CRT, respectively, and significantly (p < 0.001) reduced heart doses (mean = 2.83 ± 1.26 Gy) compared to both IMRT and 3D-CRT (mean = 3.70 ± 1.44 Gy and 3.91 ± 1.58 Gy). Static tomotherapy is the dosimetrically superior modality for the whole breast with an SIB compared with IMRT and 3D-CRT. IMRT is superior to 3D

  10. Development of a compact radiation-hardened low-noise front-end readout ASIC for CZT-based hard X-ray imager

    NASA Astrophysics Data System (ADS)

    Gao, W.; Gan, B.; Li, X.; Wei, T.; Gao, D.; Hu, Y.

    2015-04-01

    In this paper, we present the development and performances of a radiation-hardened front-end readout application-specific integrated circuit (ASIC) dedicated to CZT detectors for a hard X-ray imager in space applications. The readout channel consists of a charge sensitive amplifier (CSA), a CR-RC shaper, a fast shaper, a discriminator and a driving buffer. With the additional digital filtering, the readout channel can achieve very low noise performances and low power dissipation. An eight-channel prototype ASIC is designed and fabricated in 0.35 μm CMOS process. The energy range of the detected X-rays is evaluated as 1.45 keV to 281 keV. The gain is larger than 100 mV/fC. The equivalent noise charge (ENC) of the ASIC is 53 e- at zero farad plus 10 e- per picofarad. The power dissipation is less than 4.4 mW/channel. Through the measurement with a CZT detector, the energy resolution is less than 3.45 keV (FWHM) under the irradiation of the radioactive source 241Am. The radiation effect experiments indicate that the proposed ASIC can resist the total ionization dose (TID) irradiation of higher than 200 krad (Si).

  11. Flight performance of an advanced CZT imaging detector in a balloon-borne wide-field hard X-ray telescope—ProtoEXIST1

    NASA Astrophysics Data System (ADS)

    Hong, J.; Allen, B.; Grindlay, J.; Barthelemy, S.; Baker, R.; Garson, A.; Krawczynski, H.; Apple, J.; Cleveland, W. H.

    2011-10-01

    We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes such as the High Energy Telescope (HET) in the Energetic X-ray Imaging Survey Telescope (EXIST). The CZT detector plane in ProtoEXIST1 consists of an 8×8 array of closely tiled 2 cm×2 cm×0.5 cm thick pixellated CZT crystals, each with 8×8 pixels, mounted on a set of readout electronics boards and covering a 256 cm2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30-600 keV band for imaging, allowing a fully coded field of view of 9°×9° (and 19°×19° for 50% coding fraction) with an angular resolution of 20‧. In order to reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. On the back side, a 26 cm×26 cm×2 cm CsI(Na) active shield provides signals to tag charged particle induced events as well as ≳100keV background photons from below. The flight duration was only about 7.5 h due to strong winds (60 knots) at float altitude (38-39 km). Throughout the flight, the CZT detector performed excellently. The telescope observed Cyg X-1, a bright black hole binary system, for ˜1h at the end of the flight. Despite a few problems with the pointing and aspect systems that caused the telescope to track about 6.4° off the target, the analysis of the Cyg X-1 data revealed an X-ray source at 7.2σ in the 30-100 keV energy band at the expected location from the optical images taken by the onboard daytime star camera. The success of this first flight is very

  12. Scatter and crosstalk corrections for {sup 99m}Tc/{sup 123}I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators

    SciTech Connect

    Fan, Peng; Hutton, Brian F.; Holstensson, Maria; Ljungberg, Michael; Hendrik Pretorius, P.; Prasad, Rameshwar; Liu, Chi; Ma, Tianyu; Liu, Yaqiang; Wang, Shi; Thorn, Stephanie L.; Stacy, Mitchel R.; Sinusas, Albert J.

    2015-12-15

    Purpose: The energy spectrum for a cadmium zinc telluride (CZT) detector has a low energy tail due to incomplete charge collection and intercrystal scattering. Due to these solid-state detector effects, scatter would be overestimated if the conventional triple-energy window (TEW) method is used for scatter and crosstalk corrections in CZT-based imaging systems. The objective of this work is to develop a scatter and crosstalk correction method for {sup 99m}Tc/{sup 123}I dual-radionuclide imaging for a CZT-based dedicated cardiac SPECT system with pinhole collimators (GE Discovery NM 530c/570c). Methods: A tailing model was developed to account for the low energy tail effects of the CZT detector. The parameters of the model were obtained using {sup 99m}Tc and {sup 123}I point source measurements. A scatter model was defined to characterize the relationship between down-scatter and self-scatter projections. The parameters for this model were obtained from Monte Carlo simulation using SIMIND. The tailing and scatter models were further incorporated into a projection count model, and the primary and self-scatter projections of each radionuclide were determined with a maximum likelihood expectation maximization (MLEM) iterative estimation approach. The extracted scatter and crosstalk projections were then incorporated into MLEM image reconstruction as an additive term in forward projection to obtain scatter- and crosstalk-corrected images. The proposed method was validated using Monte Carlo simulation, line source experiment, anthropomorphic torso phantom studies, and patient studies. The performance of the proposed method was also compared to that obtained with the conventional TEW method. Results: Monte Carlo simulations and line source experiment demonstrated that the TEW method overestimated scatter while their proposed method provided more accurate scatter estimation by considering the low energy tail effect. In the phantom study, improved defect contrasts were

  13. Development of a novel filter cartridge system with electropositive granule media to concentrate viruses from large volumes of natural surface water.

    PubMed

    Jin, Min; Guo, Xuan; Wang, Xin-Wei; Yang, Dong; Shen, Zhi-Qiang; Qiu, Zhi-Gang; Chen, Zhao-Li; Li, Jun-Wen

    2014-06-17

    Exposure to various infectious viruses in environmental drinking water can constitute a public health risk. However, it is difficult to detect viruses in water due to their low concentration. In this study, we have developed a novel filter cartridge system containing electropositive granule media (EGM). Viruses present in large volumes of environmental samples were adsorbed onto the EGM, and then recovered by elution and poly(ethylene glycol) (PEG) concentration. To evaluate the system's efficiency in viral recovery, poliovirus (PV-1), a surrogate for enteric viruses, was used to artificially contaminate river water samples which were then assayed by quantitative real-time PCR. To optimize the concentration procedure, the eluent type, water flow rate and properties (e.g., pH, bacterial, and viral loads), were evaluated. The highest virus recovery was obtained by pumping river water at a flow rate of 300 mL/min and then pushing 3 L of an eluent containing 3× broth [1.5% (w/v) NaCl, 3% (w/v) tryptone, 1.5% (w/v) beef powder] with 0.05 mol/L glycine through the filter. Using this procedure, the recovery efficiencies of PV-1 from 10 to 100 L of spiked river water were up to 99%. In addition, this method is virus load and pH dependent. Virus recovery was maximal at a load of between 10(3.5) and 10(5.5) TCID50 and a pH ranging from 5 to 7. The bacterial load in the water has no effect on virus recovery. Different types of viruses and surface water were tested to validate the system's applicability. Results revealed that the EGM filter cartridge was able to concentrate PV-1, human adenoviruses (HAdVs) and noroviruses (HuNoVs) with high efficiency from river, lake, and reservoir water. Furthermore, it showed more efficient recovery than glass wool and 1MDS filters. These data suggest that this system provides rapid and efficient virus recovery from a large volume of natural surface water and, as such, could be a useful tool in revealing the presence of viruses in surface

  14. Towards large volume big divisor D3/D7 " μ-split supersymmetry" and Ricci-flat Swiss-cheese metrics, and dimension-six neutrino mass operators

    NASA Astrophysics Data System (ADS)

    Dhuria, Mansi; Misra, Aalok

    2012-02-01

    We show that it is possible to realize a " μ-split SUSY" scenario (Cheng and Cheng, 2005) [1] in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for Σ obtained in Misra and Shukla (2010) [2] based on GLSM techniques, and the Donaldson's algorithm (Barun et al., 2008) [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) [4] pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.

  15. Analysis of ten abused drugs in urine by large volume sample stacking-sweeping capillary electrophoresis with an experimental design strategy.

    PubMed

    Ho, Yu-Hsiang; Wang, Chun-Chi; Hsiao, Yu-Tzu; Ko, Wei-Kung; Wu, Shou-Mei

    2013-06-21

    A statistical tool equipped with Plackett-Burman design (PBD) and central composite design (CCD) was used for fast stacking analysis of ten frequently consumed drugs, namely codeine, morphine, methamphetamine, ketamine, alprazolam, clonazepam, diazepam, flunitrazepam, nitrazepam and oxazepam, by capillary electrophoresis (CE). This statistical design is expected to help quick analysis with few procedures, avoiding tedious work required because of the large number of variables or parameters. A large volume sample stacking (LVSS)-sweeping CE is developed for concentrating and analyzing the 10 abused drugs. First, phosphate buffer (50 mM, pH 2.3) containing methanol was filled into a capillary and then the extracted urine sample was loaded (1 psi, 200 s) to enhance sensitivity. The sweeping and separating steps were completed simultaneously by phosphate buffer (50 mM, pH 2.3) containing methanol and sodium dodecyl sulfate, within 15 min. Better resolution was obtained by the experimental design than the "one factor at a time" (OFAT) approach. During method validation, calibration plots were linear (r>0.998), over a range of 25-1500 ng/mL for the six benzodiazepines, methamphetamine and ketamine, and 50-3000 ng/mL for codeine and morphine. The RSD of precision and absolute RE of accuracy in intra-day and inter-day assays were below 14.54% and 16.61%, respectively. The minimum limits for detection (S/N=3) of analytes were in the range of 7.5-30 ng/mL. This stacking method increased sensitivity more than 200-fold and can be applied for detection of the presence of methamphetamine in an abuser's urine (3600 ng/mL), which was confirmed by GC-MS. The method is considered feasible for fast screening of abused drugs in urine.

  16. A new development of the dynamic procedure in large-eddy simulation based on a Finite Volume integral approach. Application to stratified turbulence

    NASA Astrophysics Data System (ADS)

    Denaro, Filippo Maria; de Stefano, Giuliano

    2011-10-01

    A Finite Volume-based large-eddy simulation method is proposed along with a suitable extension of the dynamic modelling procedure that takes into account for the integral formulation of the governing filtered equations. Discussion about the misleading interpretation of FV in some literature is addressed. Then, the classical Germano identity is congruently rewritten in such a way that the determination of the modelling parameters does not require any arbitrary averaging procedure and thus retains a fully local character. The numerical modelling of stratified turbulence is the specific problem considered in this study, as an archetypal of simple geophysical flows. The original scaling formulation of the dynamic sub-grid scale model proposed by Wong and Lilly (Phys. Fluids 6(6), 1994) is suitably extended to the present integral formulation. This approach is preferred with respect to traditional ones since the eddy coefficients can be independently computed by avoiding the addition of unjustified buoyancy production terms in the constitutive equations. Simple scaling arguments allow us not to use the equilibrium hypothesis according to which the dissipation rate should equal the sub-grid scale energy production. A careful a priori analysis of the relevance of the test filter shape as well as the filter-to-grid ratio is reported. Large-eddy simulation results are a posteriori compared with a reference pseudo-spectral direct numerical solution that is suitably post-filtered in order to have a meaningful comparison. In particular, the spectral distribution of kinetic and thermal energy as well as the viscosity and diffusivity sub-grid scale profiles are illustrated. The good performances of the proposed method, in terms of both evolutions of global quantities and statistics, are very promising for the future development and application of the method.

  17. Development of high internal phase emulsion polymeric monoliths for highly efficient enrichment of trace polycyclic aromatic hydrocarbons from large-volume water samples.

    PubMed

    Su, Rihui; Ruan, Guihua; Nie, Honggang; Xie, Ting; Zheng, Yanjie; Du, Fuyou; Li, Jianping

    2015-07-31

    In this work, polymerized high internal phase emulsion (polyHIPE) monoliths were prepared and applied as monolithic adsorbent materials for proconcentration of trace polycyclic aromatic hydrocarbons (PAHs) from large-volume water samples. The monolithic polyHIPE columns were prepared by in situ polymerization of the continuous phase of a high internal phase emulsion (HIPE) containing styrene (STY), divinylbenzene (DVB) and glycidyl methacrylate (GMA) in pipette tips, and the resulting STY/DVB/GMA polyHIPE monoliths exhibited highly interconnected porosity and large surface areas, making them excellent candidates as adsorbents for enrichment of trace aromatic compounds. The prepared STY/DVB/GMA polyHIPE monoliths were applied to the determination of trace PAHs in environmental water samples by combing with high performance liquid chromatography-fluorescence detection (HPLC-FLD). Under the optimized experimental conditions, the polyHIPE monoliths could effectively enrich trace 13 PAHs from 500mL of water samples, the mean recoveries at four spiked levels were ranged from 80.7% to 115.0% with the relative standard deviations (RSDs) lower than 14%, and the detection limits (LODs) were ranged from 4.0 to 228pg/L. In addition, the prepared polyHIPE monolith was stable enough for more than 200 replicate extraction cycles without measurable loss of performance on the enrichment of PAHs, and good column-to-column repeatability was obtained with RSD less than 13%. The proposed method was applied to simultaneous analysis of 13 PAHs in water samples with satisfactory recoveries.

  18. Large Eddy Simulation of Bubbly Flow and Slag Layer Behavior in Ladle with Discrete Phase Model (DPM)-Volume of Fluid (VOF) Coupled Model

    NASA Astrophysics Data System (ADS)

    Li, Linmin; Liu, Zhongqiu; Cao, Maoxue; Li, Baokuan

    2015-07-01

    In the ladle metallurgy process, the bubble movement and slag layer behavior is very important to the refining process and steel quality. For the bubble-liquid flow, bubble movement plays a significant role in the phase structure and causes the unsteady complex turbulent flow pattern. This is one of the most crucial shortcomings of the current two-fluid models. In the current work, a one-third scale water model is established to investigate the bubble movement and the slag open-eye formation. A new mathematical model using the large eddy simulation (LES) is developed for the bubble-liquid-slag-air four-phase flow in the ladle. The Eulerian volume of fluid (VOF) model is used for tracking the liquid-slag-air free surfaces and the Lagrangian discrete phase model (DPM) is used for describing the bubble movement. The turbulent liquid flow is induced by bubble-liquid interactions and is solved by LES. The procedure of bubble coming out of the liquid and getting into the air is modeled using a user-defined function. The results show that the present LES-DPM-VOF coupled model is good at predicting the unsteady bubble movement, slag eye formation, interface fluctuation, and slag entrainment.

  19. Rapid and sensitive solid phase extraction-large volume injection-gas chromatography for the analysis of mineral oil saturated and aromatic hydrocarbons in cardboard and dried foods.

    PubMed

    Moret, Sabrina; Barp, Laura; Purcaro, Giorgia; Conte, Lanfranco S

    2012-06-22

    A rapid off-line solid phase extraction-large volume injection-gas chromatography-flame ionisation detection (SPE-LVI-GC-FID) method, based on the use of silver silica gel and low solvent consumption, was developed for mineral oil saturated hydrocarbon (MOSH) and mineral oil aromatic hydrocarbon (MOAH) determination in cardboard and dried foods packaged in cardboard. The SPE method was validated using LVI with a conventional on-column injector and the retention gap technique (which allowed to inject up to 50 μL of the sample). Detector response was linear over all the concentration range tested (0.5-250 μg/mL), recoveries were practically quantitative, repeatability was good (coefficients of variation lower than 7%) and limit of quantification adequate to quantify the envisioned limit of 0.15 mg/kg proposed in Germany for MOAH analysis in food samples packaged in recycled cardboard. Rapid heating of the GC oven allowed to increase sample throughput (3-4 samples per hour) and to enhance sensitivity. The proposed method was used for MOSH and MOAH determination in selected food samples usually commercialised in cardboard packaging. The most contaminated was a tea sample (102.2 and 7.9 mg/kg of MOSH and MOAH below n-C25, respectively), followed by a rice and a sugar powder sample, all packaged in recycled cardboard.

  20. Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.

    PubMed

    Li, Pingjing; Zhang, Xing; Hu, Bin

    2011-12-30

    In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 μL of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples.