WorldWideScience

Sample records for direct thermal desorption

  1. The direct determination of HgS by thermal desorption coupled with atomic absorption spectrometry

    Czech Academy of Sciences Publication Activity Database

    Coufalík, Pavel; Zvěřina, O.; Komárek, J.

    2016-01-01

    Roč. 118, APR (2016), s. 1-5 ISSN 0584-8547 Institutional support: RVO:68081715 Keywords : mercury * HgS * thermal desorption Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.241, year: 2016

  2. Determination of the carbon isotopic composition of whole/intact biological specimens using at-line direct thermal desorption to effect thermally assisted hydrolysis/methylation

    NARCIS (Netherlands)

    Akoto, L.; Vreuls, R.J.J.; Irth, H.; Floris, V.; Hoogveld, H.L.; Pel, R.

    2008-01-01

    In this paper, we discuss the use of a direct thermal desorption (DTD) interface as an alternative to Curie-point flash pyrolysis system as an inlet technique in gas chromatography–combustion isotope-ratio mass spectrometry (GC/C-IRMS) analysis of whole/intact phytoplankton and zooplankton

  3. Direct Detection of Pharmaceuticals and Personal Care Products from Aqueous Samples with Thermally-Assisted Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Campbell, Ian S.; Ton, Alain T.; Mulligan, Christopher C.

    2011-07-01

    An ambient mass spectrometric method based on desorption electrospray ionization (DESI) has been developed to allow rapid, direct analysis of contaminated water samples, and the technique was evaluated through analysis of a wide array of pharmaceutical and personal care product (PPCP) contaminants. Incorporating direct infusion of aqueous sample and thermal assistance into the source design has allowed low ppt detection limits for the target analytes in drinking water matrices. With this methodology, mass spectral information can be collected in less than 1 min, consuming ~100 μL of total sample. Quantitative ability was also demonstrated without the use of an internal standard, yielding decent linearity and reproducibility. Initial results suggest that this source configuration is resistant to carryover effects and robust towards multi-component samples. The rapid, continuous analysis afforded by this method offers advantages in terms of sample analysis time and throughput over traditional hyphenated mass spectrometric techniques.

  4. At-line gas chromatographic-mass spectrometric analysis of fatty acid profiles of green microalgae using a direct thermal desorption interface

    NARCIS (Netherlands)

    Blokker, P.; Pel, R.; Akoto, L.; Udo, A.; Brinkman, U.A.Th.; Vreuls, R.J.J.

    2002-01-01

    Thermally assisted hydrolysis and methylation¯gas chromatography (THM¯GC) is an important tool to analyse fatty acid in complex matrices. Since THM¯GC has major drawbacks such as isomerisation when applied to fatty acids in natural matrices, a direct thermal desorption (DTD) interface and an

  5. Detection of Nonvolatile Inorganic Oxidizer-Based Explosives from Wipe Collections by Infrared Thermal Desorption-Direct Analysis in Real Time Mass Spectrometry.

    Science.gov (United States)

    Forbes, Thomas P; Sisco, Edward; Staymates, Matthew

    2018-05-07

    Infrared thermal desorption (IRTD) was coupled with direct analysis in real time mass spectrometry (DART-MS) for the detection of both inorganic and organic explosives from wipe collected samples. This platform generated discrete and rapid heating rates that allowed volatile and semivolatile organic explosives to thermally desorb at relatively lower temperatures, while still achieving elevated temperatures required to desorb nonvolatile inorganic oxidizer-based explosives. IRTD-DART-MS demonstrated the thermal desorption and detection of refractory potassium chlorate and potassium perchlorate oxidizers, compounds difficult to desorb with traditional moderate-temperature resistance-based thermal desorbers. Nanogram to sub-nanogram sensitivities were established for analysis of a range of organic and inorganic oxidizer-based explosive compounds, with further enhancement limited by the thermal properties of the most common commercial wipe materials. Detailed investigations and high-speed visualization revealed conduction from the heated glass-mica base plate as the dominant process for heating of the wipe and analyte materials, resulting in thermal desorption through boiling, aerosolization, and vaporization of samples. The thermal desorption and ionization characteristics of the IRTD-DART technique resulted in optimal sensitivity for the formation of nitrate adducts with both organic and inorganic species. The IRTD-DART-MS coupling and IRTD in general offer promising explosive detection capabilities to the defense, security, and law enforcement arenas.

  6. Characterization of olive oil volatiles by multi-step direct thermal desorption-comprehensive gas chromatography-time-of-flight mass spectrometry using a programmed temperature vaporizing injector

    NARCIS (Netherlands)

    de Koning, S.; Kaal, E.; Janssen, H.-G.; van Platerink, C.; Brinkman, U.A.Th.

    2008-01-01

    The feasibility of a versatile system for multi-step direct thermal desorption (DTD) coupled to comprehensive gas chromatography (GC × GC) with time-of-flight mass spectrometric (TOF-MS) detection is studied. As an application the system is used for the characterization of fresh versus aged olive

  7. Direct analysis of anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption-dielectric barrier discharge ionization mass spectrometry.

    Science.gov (United States)

    Saha, Subhrakanti; Mandal, Mridul Kanti; Nonami, Hiroshi; Hiraoka, Kenzo

    2014-08-11

    Rapid detection of trace level anabolic steroids in urine is highly desirable to monitor the consumption of performance enhancing anabolic steroids by athletes. The present article describes a novel strategy for identifying the trace anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption (LPTD) coupled to dielectric barrier discharge (DBD) ionization mass spectrometry. Using this method the steroid molecules are enriched within a liquid droplet during the thermal desorption process and desorbed all-together at the last moment of droplet evaporation in a short time domain. The desorbed molecules were ionized using a dielectric barrier discharge ion-source in front of the mass spectrometer inlet at open atmosphere. This process facilitates the sensitivity enhancement with several orders of magnitude compared to the thermal desorption at a lower temperature. The limits of detection (LODs) of various steroid molecules were found to be in the range of 0.05-0.1 ng mL(-1) for standard solutions and around two orders of magnitude higher for synthetic urine samples. The detection limits of urinary anabolic steroids could be lowered by using a simple and rapid dichloromethane extraction technique. The analytical figures of merit of this technique were evaluated at open atmosphere using suitable internal standards. The technique is simple and rapid for high sensitivity and high throughput screening of anabolic steroids in urine. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Direct thermal desorption in the analysis of cheese volatiles by gas chromatography and gas chromatography-mass spectrometry: comparison with simultaneous distillation-extraction and dynamic headspace.

    Science.gov (United States)

    Valero, E; Sanz, J; Martínez-Castro, I

    2001-06-01

    Direct thermal desorption (DTD) has been used as a technique for extracting volatile components of cheese as a preliminary step to their gas chromatographic (GC) analysis. In this study, it is applied to different cheese varieties: Camembert, blue, Chaumes, and La Serena. Volatiles are also extracted using other techniques such as simultaneous distillation-extraction and dynamic headspace. Separation and identification of the cheese components are carried out by GC-mass spectrometry. Approximately 100 compounds are detected in the examined cheeses. The described results show that DTD is fast, simple, and easy to automate; requires only a small amount of sample (approximately 50 mg); and affords quantitative information about the main groups of compounds present in cheeses.

  9. Thermal desorption study of physical forces at the PTFE surface

    Science.gov (United States)

    Wheeler, D. R.; Pepper, S. V.

    1987-01-01

    Thermal desorption spectroscopy (TDS) of the polytetrafluoroethylene (PTFE) surface was successfully employed to study the possible role of physical forces in the enhancement of metal-PTFE adhesion by radiation. The thermal desorption spectra were analyzed without assumptions to yield the activation energy for desorption over a range of xenon coverage from less than 0.1 monolayer to more than 100 monolayers. For multilayer coverage, the desorption is zero-order with an activation energy equal to the sublimation energy of xenon. For submonolayer coverages, the order for desorption from the unirradiated PTFE surface is 0.73 and the activation energy for desorption is between 3.32 and 3.36 kcal/mol; less than the xenon sublimation energy. The effect of irradiation is to increase the activation energy for desorption to as high as 4 kcal/mol at low coverage.

  10. Thermal desorption and surface modification of He+ implanted into tungsten

    International Nuclear Information System (INIS)

    Fu Zhang; Yoshida, N.; Iwakiri, H.; Xu Zengyu

    2004-01-01

    Tungsten divertor plates in fusion reactors will be subject to helium bombardment. Helium retention and thermal desorption is a concerned issue in controlling helium ash. In the present study, fluence dependence of thermal desorption behavior of helium in tungsten was studied at different irradiation temperatures and ion energies. Results showed that helium desorption could start at ∼400 K with increasing fluence, while no noticeable peaks were detected at low fluence. Total helium desorption reached a saturation value at high fluence range, which was not sensitive to irradiation temperature or ion energy for the conditions evaluated. Surface modifications caused by either ion irradiation or thermal desorption were observed by SEM. The relationship of surface modifications and helium desorption behavior was discussed. Some special features of elevated irradiation temperature and lower ion energy were also indicated

  11. Initial screening of thermal desorption for soil remediation

    International Nuclear Information System (INIS)

    Yezzi, J.J. Jr.; Tafuri, A.N.; Rosenthal, S.; Troxler, W.L.

    1994-01-01

    Petroleum-contaminated soils--caused by spills, leaks, and accidental discharges--exist at many sites throughout the United States. Thermal desorption technologies which are increasingly being employed to treat these soils, have met soil cleanup criteria for a variety of petroleum products. Currently the United States Environmental Protection Agency is finalizing a technical report entitled Use of Thermal Desorption for Treating Petroleum-Contaminated Soils to assist remedial project managers, site owners, remediation contractors, and equipment vendors in evaluating the use of thermal desorption technologies for petroleum-contaminated soil applications. The report will present a three-level screening method to help a reader predict the success of applying thermal desorption at a specific site. The objective of screening level one is to determine the likelihood of success in a specific application of thermal desorption. It will take into account procedures for collecting and evaluating data on site characteristics, contaminant characteristics, soil characteristics, and regulatory requirements. This level will establish whether or not thermal desorption should be evaluated further for site remediation, whether treatment should occur on-site or off-site, and if on-site is a viable option, what system size will be most cost-effective. The scope of this paper addresses only screening level one which provides a preliminary assessment of the applicability of thermal desorption to a particular site. This topic encompasses worksheets that are an integral part of the ''user friendly'' screening process. Level one screening provides a foundation for the subsequent two levels which follow a similar ''user friendly'' worksheet approach to evaluating thermal desorption technologies and establishing costs for thermal desorption in an overall remediation project

  12. Fatty acid profiling of raw human plasma and whole blood using direct thermal desorption combined with gas chromatography–mass spectrometry

    NARCIS (Netherlands)

    Akoto, L.; Vreuls, R.J.J.; Irth, H.; Pel, R.; Stellaard, F.

    2008-01-01

    Gas chromatography (GC) has in recent times become an important tool for the fatty acid profiling of human blood and plasma. An at-line procedure used in the fatty acid profiling of whole/intact aquatic micro-organisms without any sample preparation was adapted for this work. A direct thermal

  13. Fatty acid profiling of raw human plasma and whole blood using direct thermal desorption combined with gas chromatography-mass spectrometry.

    NARCIS (Netherlands)

    Akoto, L.; Vreuls, J.J.; Irth, H.; Pel, R.; Stellaard, F.

    2008-01-01

    Gas chromatography (GC) has in recent times become an important tool for the fatty acid profiling of human blood and plasma. An at-line procedure used in the fatty acid profiling of whole/intact aquatic micro-organisms without any sample preparation was adapted for this work. A direct thermal

  14. Fatty acid profiling of raw human plasma and whole blood using direct thermal desorption combined with gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Akoto, Lawrence; Vreuls, Rene J. J.; Irth, Hubertus; Pel, Roel; Stellaard, Frans

    2008-01-01

    Gas chromatography (GC) has in recent times become an important tool for the fatty acid profiling of human blood and plasma. An at-line procedure used in the fatty acid profiling of whole/intact aquatic micro-organisms without any sample preparation was adapted for this work. A direct thermal

  15. Spatially resolved thermal desorption/ionization coupled with mass spectrometry

    Science.gov (United States)

    Jesse, Stephen; Van Berkel, Gary J; Ovchinnikova, Olga S

    2013-02-26

    A system and method for sub-micron analysis of a chemical composition of a specimen are described. The method includes providing a specimen for evaluation and a thermal desorption probe, thermally desorbing an analyte from a target site of said specimen using the thermally active tip to form a gaseous analyte, ionizing the gaseous analyte to form an ionized analyte, and analyzing a chemical composition of the ionized analyte. The thermally desorbing step can include heating said thermally active tip to above 200.degree. C., and positioning the target site and the thermally active tip such that the heating step forms the gaseous analyte. The thermal desorption probe can include a thermally active tip extending from a cantilever body and an apex of the thermally active tip can have a radius of 250 nm or less.

  16. Quantification of 2,5-dimethyl-4-hydroxy-3(2H)-furanone using solid-phase extraction and direct microvial insert thermal desorption gas chromatography-mass spectrometry.

    Science.gov (United States)

    Du, Xiaofen; Qian, Michael

    2008-10-24

    A GC-MS method for the determination of furaneol in fruit juice was developed using Lichrolut-EN solid-phase extraction (SPE) coupled to microvial insert thermal desorption. Lichrolut-EN can effectively extract furaneol from juice, and had much less retention for pigments and other non-volatiles than HLB and C18 columns. The furaneol can be completely eluted out from the Lichrolut-EN SPE column with 1mL of methanol, which can be directly analyzed on GC-MS using an automated large volume microvial insert thermal desorption technique without further purification and concentration. The method is sensitive, has good recovery (98%) and reproducibility (CVfuraneol in some commonly grown strawberry, raspberry, and blackberry cultivars in Pacific Northwest of the United States was determined. Strawberries had the highest concentration of furaneol with 'Totem' and 'Pinnacle' cultivars over 13mgkg(-1) fruit. 'Marion' blackberry had 5 times more furaneol than 'Black Diamond', and 16 times more than 'Thornless Evergreen' blackberry. Raspberries had furaneol concentration ranged from 0.8 to 1.1mgkg(-1) fruit.

  17. Thermal desorption of deuterium implanted into beryllium

    International Nuclear Information System (INIS)

    Markin, A.V.; Chernikov, V.N.; Zakharov, A.P.

    1995-01-01

    By means of TDS measurements it is shown that the desorption of deuterium from Be implanted with 5 keV D ions to fluences, Φ, from 1x10 20 D/m 2 to 1x10 21 D/m 2 proceeds in one high temperature stage B, while at Φ ≥ 1.2x10 21 D/m 2 one more stage A is added. The desorption maximum A is narrow and consists of two peaks A 1 and A 2 at about 460 K and 490 K, respectively. Peak A 1 is attributed to the desorption of deuterium from the walls of opened channels formed under D ion implantation. Peak A 2 is a consequence of the opening of a part of closed bubbles/channels to the outer surface. The position of maximum B shifts noticeably and nonsteadily on the fluence in a range from 850 to 1050 K. The origin of this maximum is the liberation of D atoms bound at vacancy complexes discussed previously by Wampler. The dependence of Tm(B) on the fluence is governed by the interaction of freely migrating D atoms with partly opened or fully closed gas cavity arrangements which are created under temperature ramping, but differently in specimens implanted with D ions to different fluences

  18. Impact of neutron irradiation on thermal helium desorption from iron

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xunxiang, E-mail: hux1@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Field, Kevin G. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Taller, Stephen [University of Michigan, Ann Arbor, MI 48109 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wirth, Brian D. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); University of Tennessee, Knoxville, TN 37996 (United States)

    2017-06-15

    The synergistic effect of neutron irradiation and transmutant helium production is an important concern for the application of iron-based alloys as structural materials in fission and fusion reactors. In this study, we investigated the impact of neutron irradiation on thermal helium desorption behavior in high purity iron. Single crystalline and polycrystalline iron samples were neutron irradiated in HFIR to 5 dpa at 300 °C and in BOR-60 to 16.6 dpa at 386 °C, respectively. Following neutron irradiation, 10 keV He ion implantation was performed at room temperature on both samples to a fluence of 7 × 10{sup 18} He/m{sup 2}. Thermal desorption spectrometry (TDS) was conducted to assess the helium diffusion and clustering kinetics by analyzing the desorption spectra. The comparison of He desorption spectra between unirradiated and neutron irradiated samples showed that the major He desorption peaks shift to higher temperatures for the neutron-irradiated iron samples, implying that strong trapping sites for He were produced during neutron irradiation, which appeared to be nm-sized cavities through TEM examination. The underlying mechanisms controlling the helium trapping and desorption behavior were deduced by assessing changes in the microstructure, as characterized by TEM, of the neutron irradiated samples before and after TDS measurements.

  19. Study of defects near molybdenum surface using thermal desorption spectrometer

    International Nuclear Information System (INIS)

    Naik, P.K.

    1980-01-01

    Thermal desorption spectrometry is utilized to study the migration of atoms and defects near molybdenum surface. The thermal desorption spectra of inert gas ions (neon, argon and krypton) injected with various energies (430-1950 eV) into a polycrystalline molybdenum target with various dosages (6.4 x 10sup(12) - 3.9 x 10sup(14) ions/cmsup(2)) are investigated. Four different states of binding of the trapped atoms corresponding to the activation energies for desorption have been revealed from the spectra. The activation energies are found to be relatively insensitive to the species of the bombarding ion, incident ion energy and the dosage. The patterns of the spectra are strongly influenced by the mean projected range of the ions into the solid. The activation energies deduced are in good agreement with those reported for the migration of atoms and defects in molybdenum. (auth.)

  20. Solid Waste Decontamination by Thermal Desorption and Catalytic Oxidation Methods

    Czech Academy of Sciences Publication Activity Database

    Šolcová, Olga; Topka, Pavel; Soukup, Karel; Jirátová, Květa; Váňová, H.; Kaštánek, František

    2014-01-01

    Roč. 68, č. 9 (2014), s. 1279-1282 ISSN 0366-6352 R&D Projects: GA MPO FR-TI1/059 Institutional support: RVO:67985858 Keywords : thermal desorption * catalytic oxidation * soil decontamination Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.468, year: 2014

  1. Rapid screening of pharmaceutical drugs using thermal desorption – SALDI mass spectrometry

    International Nuclear Information System (INIS)

    Grechnikov, A A; Kubasov, A E; Borodkov, A S; Georgieva, V B; Nikiforov, S M; Simanovsky, Ya O; Alimpiev, S S

    2012-01-01

    A novel approach to the rapid screening of pharmaceutical drugs by surface assisted laser desorption-ionization (SALDI) mass spectrometry with the rotating ball interface coupled with temperature programmed thermal desorption has been developed. Analytes were thermally desorbed and deposited onto the surface of amorphous silicon substrate attached to the rotating ball. The ball was rotated and the deposited analytes were analyzed using SALDI. The effectiveness of coupling SALDI mass spectrometry with thermal desorption was evaluated by the direct and rapid analysis of tablets containing lidocaine, diphenhydramine and propranolol without any sample pretreatment. The overall duration of the screening procedure was 30÷40 sec. Real urine samples were studied for drug analysis. It is shown that with simple preparation steps, urine samples can be quantitatively analyzed using the proposed technique with the detection limits in the range of 0.2÷0.5 ng/ml.

  2. Behavior of sorption and thermal desorption of fission products from loaded metal oxide exchangers

    International Nuclear Information System (INIS)

    Buerck, J.

    1986-08-01

    A new sublimation method for the concentration and purification of 99 Mo, produced by the fission of 235 U with thermal neutrons, has been developed to replace the present final decontamination steps in the various well established 99 Mo separation processes. A distinct simplification and shortening of the actual procedure is obtained by combining the chromatographic sorption on the SnO 2 -exchanger with the direct thermal desorption of the Mo product from the oxide. (orig./PW) [de

  3. The Design and Development of Enhanced Thermal Desorption Products

    Directory of Open Access Journals (Sweden)

    R. Humble

    2005-01-01

    Full Text Available This research study is based on a knowledge-transfer collaboration between The National Centre for Product Design and Development Research (PDR and Markes International Ltd. The aim of the two-year collaboration has been to implement design tools and techniques for the development of enhanced thermal desorption products. Thermal desorption is a highly-specialised technique for the analysis of trace-level volatile organic compounds. This technique allows minute quantities of these compounds to be measured; however, there is an increasing demand from customers for greater sensitivity over a wider range of applications, which means new design methodologies need to be evaluated. The thermal desorption process combines a number of disparate chemical, thermal and mechanical disciplines, and the major design constraints arise from the need to cycle the sample through extremes in temperature. Following the implementation of a comprehensive product design specification, detailed design solutions have been developed using the latest 3D CAD techniques. The impact of the advanced design techniques is assessed in terms of improved product performance and reduced development times, and the wider implications of new product development within small companies are highlighted.  

  4. Case study of manufactured gas plant site remediations using thermal desorption

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, R.G.; Hayes, T.; Slimon, K.F.; Unites, D. [Southern California Gas Company, Los Angeles, CA (United States)

    1995-12-31

    Southern California Gas Company (SoCal Gas) has recently remediated five of its former manufactured gas plant (MGP) sites using on-site and off-site thermal desorption. This technology has proven effective in the treatment of PAH-contaminated soils with widely variable concentrations. At two of the five sites, MGP-contaminated materials were excavated and thermally treated on site. At the other sites, MGP-contaminated materials were excavated and transported directly to an off-site thermal desorber. Much of the production was of oil-gas, giving lampblack contamination, but some coal tar was also present.

  5. Thermal desorption spectroscopy for investigating hydrogen isotope behavior in materials

    International Nuclear Information System (INIS)

    Xia Tirui; Yang Hongguang; Zhan Qin; Han Zhibo; He Changshui

    2012-01-01

    The behavior of hydrogen isotope generated in fusion reactor materials is the key issue for safety and economic operation of fusion reactors and becomes an interesting field. In order to investigate the mechanism of hydrogen isotope such as diffusion, release and retention, a high-sensitivity thermal desorption spectroscopy (TDS) in combination with a quadruple mass spectrometer (QMS) was developed. A major technical breakthrough in ultrahigh vacuum (UHV), low hydrogen background, linear heating and sensitivity calibration of TDS system was made. UHV of l × 10 -7 Pa and low hydrogen background of l × 10 -9 Pa were obtained by combining turbo molecule pump and sputter ion pump. Specimens can be linearly heated up to 1173 K at the rate of 1 to 50 K/min under the MCGS PID software. Sensitivity calibration of the TDS system was accomplished using a special deuterium leak in the detector mode of QMS second electron multiplier. The desorption sensitivity coefficient and the minimum detection limit of deuterium desorption rate are 6.22 × l0 24 s -l · and l.24 × l0 -10 s -1 , respectively. The measurement was also routinely conducted on a specimen of standard, deuterium-containing Zr-4 alloy maintained in the laboratory, so as to validate the TDS method. (authors)

  6. Comparison of a disposable sorptive sampler with thermal desorption in a gas chromatographic inlet, or in a dedicated thermal desorber, to conventional stir bar sorptive extraction-thermal desorption for the determination of micropollutants in water.

    Science.gov (United States)

    Wooding, Madelien; Rohwer, Egmont R; Naudé, Yvette

    2017-09-01

    The presence of micropollutants in the aquatic environment is a worldwide environmental concern. The diversity of micropollutants and the low concentration levels at which they may occur in the aquatic environment have greatly complicated the analysis and detection of these chemicals. Two sorptive extraction samplers and two thermal desorption methods for the detection of micropollutants in water were compared. A low-cost, disposable, in-house made sorptive extraction sampler was compared to SBSE using a commercial Twister sorptive sampler. Both samplers consisted of polydimethylsiloxane (PDMS) as a sorptive medium to concentrate micropollutants. Direct thermal desorption of the disposable samplers in the inlet of a GC was compared to conventional thermal desorption using a commercial thermal desorber system (TDS). Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS) was used for compound separation and identification. Ten micropollutants, representing a range of heterogeneous compounds, were selected to evaluate the performance of the methods. The in-house constructed sampler, with its associated benefits of low-cost and disposability, gave results comparable to commercial SBSE. Direct thermal desorption of the disposable sampler in the inlet of a GC eliminated the need for expensive consumable cryogenics and total analysis time was greatly reduced as a lengthy desorption temperature programme was not required. Limits of detection for the methods ranged from 0.0010 ng L -1 to 0.19 ng L -1 . For most compounds, the mean (n = 3) recoveries ranged from 85% to 129% and the % relative standard deviation (% RSD) ranged from 1% to 58% with the majority of the analytes having a %RSD of less than 30%. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Organic and inorganic decomposition products from the thermal desorption of atmospheric particles

    Science.gov (United States)

    Williams, Brent J.; Zhang, Yaping; Zuo, Xiaochen; Martinez, Raul E.; Walker, Michael J.; Kreisberg, Nathan M.; Goldstein, Allen H.; Docherty, Kenneth S.; Jimenez, Jose L.

    2016-04-01

    Atmospheric aerosol composition is often analyzed using thermal desorption techniques to evaporate samples and deliver organic or inorganic molecules to various designs of detectors for identification and quantification. The organic aerosol (OA) fraction is composed of thousands of individual compounds, some with nitrogen- and sulfur-containing functionality and, often contains oligomeric material, much of which may be susceptible to decomposition upon heating. Here we analyze thermal decomposition products as measured by a thermal desorption aerosol gas chromatograph (TAG) capable of separating thermal decomposition products from thermally stable molecules. The TAG impacts particles onto a collection and thermal desorption (CTD) cell, and upon completion of sample collection, heats and transfers the sample in a helium flow up to 310 °C. Desorbed molecules are refocused at the head of a gas chromatography column that is held at 45 °C and any volatile decomposition products pass directly through the column and into an electron impact quadrupole mass spectrometer. Analysis of the sample introduction (thermal decomposition) period reveals contributions of NO+ (m/z 30), NO2+ (m/z 46), SO+ (m/z 48), and SO2+ (m/z 64), derived from either inorganic or organic particle-phase nitrate and sulfate. CO2+ (m/z 44) makes up a major component of the decomposition signal, along with smaller contributions from other organic components that vary with the type of aerosol contributing to the signal (e.g., m/z 53, 82 observed here for isoprene-derived secondary OA). All of these ions are important for ambient aerosol analyzed with the aerosol mass spectrometer (AMS), suggesting similarity of the thermal desorption processes in both instruments. Ambient observations of these decomposition products compared to organic, nitrate, and sulfate mass concentrations measured by an AMS reveal good correlation, with improved correlations for OA when compared to the AMS oxygenated OA (OOA

  8. Mercury speciation during in situ thermal desorption in soil

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Min, E-mail: cmpark80@gmail.com; Katz, Lynn E.; Liljestrand, Howard M.

    2015-12-30

    Highlights: • Impact of soil conditions on distribution and phase transitions of Hg was identified. • Metallic Hg was slowly transformed to Hg{sup 0} gas until the temperature reached 358.15 K. • Phase change of HgCl{sub 2(s)} completely occurred without decomposition at 335.15 K. • HgS remained solid in dry soil sharply decreased in the narrow temperature range. • Hg gas can be easily captured with higher vapor pressures of soil compositions. - Abstract: Metallic mercury (Hg{sup 0}) and its compounds are highly mobile and toxic environmental pollutants at trace level. In situ thermal desorption (ISTD) is one of the soil remediation processes applying heat and vacuum simultaneously. Knowledge of thermodynamic mercury speciation is imperative to understand the fate and transport of mercury during thermal remediation and operate the treatment processes in a cost-effective manner. Hence, speciation model for inorganic mercury was developed over a range of environmental conditions to identify distribution of dissolved mercury species and potential transformations of mercury at near source environment. Simulation of phase transitions for metallic mercury, mercury(II) chloride and mercury sulfide with temperature increase showed that complete vaporization of metallic mercury and mercury(II) chloride were achieved below the boiling point of water. The effect of soil compositions on mercury removal was also evaluated to better understand thermal remediation process. Higher vapor pressures expected both from soil pore water and inorganic carbonate minerals in soil as well as creation of permeability were significant for complete vaporization and removal of mercury.

  9. Mercury speciation during in situ thermal desorption in soil

    International Nuclear Information System (INIS)

    Park, Chang Min; Katz, Lynn E.; Liljestrand, Howard M.

    2015-01-01

    Highlights: • Impact of soil conditions on distribution and phase transitions of Hg was identified. • Metallic Hg was slowly transformed to Hg"0 gas until the temperature reached 358.15 K. • Phase change of HgCl_2_(_s_) completely occurred without decomposition at 335.15 K. • HgS remained solid in dry soil sharply decreased in the narrow temperature range. • Hg gas can be easily captured with higher vapor pressures of soil compositions. - Abstract: Metallic mercury (Hg"0) and its compounds are highly mobile and toxic environmental pollutants at trace level. In situ thermal desorption (ISTD) is one of the soil remediation processes applying heat and vacuum simultaneously. Knowledge of thermodynamic mercury speciation is imperative to understand the fate and transport of mercury during thermal remediation and operate the treatment processes in a cost-effective manner. Hence, speciation model for inorganic mercury was developed over a range of environmental conditions to identify distribution of dissolved mercury species and potential transformations of mercury at near source environment. Simulation of phase transitions for metallic mercury, mercury(II) chloride and mercury sulfide with temperature increase showed that complete vaporization of metallic mercury and mercury(II) chloride were achieved below the boiling point of water. The effect of soil compositions on mercury removal was also evaluated to better understand thermal remediation process. Higher vapor pressures expected both from soil pore water and inorganic carbonate minerals in soil as well as creation of permeability were significant for complete vaporization and removal of mercury.

  10. Study of Perylenetetracarboxylic Acid Dimethylimide Films by Cyclic Thermal Desorption and Scanning Probe Microscopy

    Science.gov (United States)

    Pochtennyi, A. E.; Lappo, A. N.; Il'yushonok, I. P.

    2018-02-01

    Some results of studying the direct-current (DC) conductivity of perylenetetracarboxylic acid dimethylimide films by cyclic oxygen thermal desorption are presented. The microscopic parameters of hopping electron transport over localized impurity and intrinsic states were determined. The bandgap width and the sign of major current carriers were determined by scanning probe microscopy methods (atomic force microscopy, scanning probe spectroscopy, and photoassisted Kelvin probe force microscopy). The possibility of the application of photoassisted scanning tunneling microscopy for the nanoscale phase analysis of photoconductive films is discussed.

  11. Sustainable remediation of mercury contaminated soils by thermal desorption.

    Science.gov (United States)

    Sierra, María J; Millán, Rocio; López, Félix A; Alguacil, Francisco J; Cañadas, Inmaculada

    2016-03-01

    Mercury soil contamination is an important environmental problem that needs the development of sustainable and efficient decontamination strategies. This work is focused on the application of a remediation technique that maintains soil ecological and environmental services to the extent possible as well as search for alternative sustainable land uses. Controlled thermal desorption using a solar furnace at pilot scale was applied to different types of soils, stablishing the temperature necessary to assure the functionality of these soils and avoid the Hg exchange to the other environmental compartments. Soil mercury content evolution (total, soluble, and exchangeable) as temperature increases and induced changes in selected soil quality indicators are studied and assessed. On total Hg, the temperature at which it is reduced until acceptable levels depends on the intended soil use and on how restrictive are the regulations. For commercial, residential, or industrial uses, soil samples should be heated to temperatures higher than 280 °C, at which more than 80 % of the total Hg is released, reaching the established legal total Hg level and avoiding eventual risks derived from high available Hg concentrations. For agricultural use or soil natural preservation, conversely, maintenance of acceptable levels of soil quality limit heating temperatures, and additional treatments must be considered to reduce available Hg. Besides total Hg concentration in soils, available Hg should be considered to make final decisions on remediation treatments and potential future uses. Graphical Abstract Solar energy use for remediation of soils affected by mercury.

  12. Thermal desorption treatability test conducted with VAC*TRAX Unit

    International Nuclear Information System (INIS)

    1996-01-01

    In 1992, Congress passed the Federal Facilities Compliance Act, requiring the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with Resource Conservation and Recovery Act (RCRA) treatment standards. In response to the need for mixed-waste treatment capacity, where off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed waste with treatment options and develop a strategy for treatment of mixed waste. DOE-AL manages nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment units (MTUs) to treat waste at the sites where the wastes are generated. Treatment processes used for mixed wastes must remove the hazardous component (i.e., meet RCRA treatment standards) and contain the radioactive component in a form that will protect the worker, public, and environment. On the basis of the recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (DOE-GJPO) include thermal desorption (TD), evaporative oxidation, and waste water evaporation

  13. Thermal Desorption Analysis of Effective Specific Soil Surface Area

    Science.gov (United States)

    Smagin, A. V.; Bashina, A. S.; Klyueva, V. V.; Kubareva, A. V.

    2017-12-01

    A new method of assessing the effective specific surface area based on the successive thermal desorption of water vapor at different temperature stages of sample drying is analyzed in comparison with the conventional static adsorption method using a representative set of soil samples of different genesis and degree of dispersion. The theory of the method uses the fundamental relationship between the thermodynamic water potential (Ψ) and the absolute temperature of drying ( T): Ψ = Q - aT, where Q is the specific heat of vaporization, and a is the physically based parameter related to the initial temperature and relative humidity of the air in the external thermodynamic reservoir (laboratory). From gravimetric data on the mass fraction of water ( W) and the Ψ value, Polyanyi potential curves ( W(Ψ)) for the studied samples are plotted. Water sorption isotherms are then calculated, from which the capacity of monolayer and the target effective specific surface area are determined using the BET theory. Comparative analysis shows that the new method well agrees with the conventional estimation of the degree of dispersion by the BET and Kutilek methods in a wide range of specific surface area values between 10 and 250 m2/g.

  14. Evaluation of contaminated soil remediation by low temperature thermal desorption

    International Nuclear Information System (INIS)

    Gibbs, L.; Punt, M.

    1993-01-01

    Soil contaminated with diesel and aviation fuels has been excavated and stored at a Canadian Forces Base in Ontario. Because of the volatile nature of this contamination, it was determined that low temperature thermal desorption (LTTD) would be an effective method of remediating this soil. A full scale evaluation of LTTD technology was conducted at the base to determine its acceptability for other sites. In the LTTD process, soil enters a primary treatment unit and is heated to a sufficiently high temperature to volatilize the hydrocarbon contaminants. Offgases are treated in a secondary combustion chamber. Primary treatment kiln temperature was maintained at 260 degree C for each test during the evaluation. The LTTD unit was evaluated for two sets of operating conditions: two levels of inlet soil total petroleum hydrocarbon concentrations and two feed rates (16,000 and 22,000 kg/h). Emissions from the LTTD unit were monitored continuously for volatile organics, moisture, and gas velocity. Results of the tests and emissions analyses are presented. Outlet soil hydrocarbon concentration requirements of 100 ppM were not exceeded during the evaluation. Air hydrocarbon emissions only exceeded 100-ppM limits under upset conditions, otherwise virturally no total hydrocarbon content was observed in the stack gas. 5 refs., 6 figs., 9 tabs

  15. Thermal desorption of deuterium from modified carbon nanotubes and its correlation to the microstructure

    NARCIS (Netherlands)

    Lisowski, W.F.; Keim, Enrico G.; van den Berg, A.H.J.; Smithers, Mark A.; Smithers, M.A.

    2006-01-01

    The process of deuterium desorption from single-wall carbon nanotubes (SWNTs) modified by atomic (D) and molecular (D2) deuterium treatment was investigated in an ultrahigh vacuum environment using thermal desorption mass spectroscopy (TDMS). Microstructural and chemical analyses of SWNT material,

  16. VAC*TRAX - Thermal desorption for mixed wastes

    International Nuclear Information System (INIS)

    McElwee, M.J.; Palmer, C.R.

    1995-01-01

    The patented VAC*TRAX process was designed in response to the need to remove organic constituents from mixed waste, waste that contains both a hazardous (RCRA or TSCA regulated) component and a radioactive component. Separation of the mixed waste into its hazardous and radioactive components allows for ultimate disposal of the material at existing, permitted facilities. The VAC*TRAX technology consists of a jacketed vacuum dryer followed by a condensing train. Solids are placed in the dryer and indirectly heated to temperatures as high as 260 degrees C, while a strong vacuum (down to 50 mm Hg absolute pressure) is applied to the system and the dryer is purged with a nitrogen carrier gas. The organic contaminants in the solids are thermally desorbed, swept up in the carrier gas and into the condensing train where they are cooled and recovered. The dryer is fitted with a filtration system that keeps the radioactive constituents from migrating to the condensate. As such, the waste is separated into hazardous liquid and radioactive solid components, allowing for disposal of these streams at a permitted incinerator or a radioactive materials landfill, respectively. The VAC*TRAX system is designed to be highly mobile, while minimizing the operational costs with a simple, robust process. These factors allow for treatment of small waste streams at a reasonable cost. This paper describes the VAC*TRAX thermal desorption process, as well as results from the pilot testing program. Also, the design and application of the full-scale treatment system is presented. Materials tested to date include spiked soil and debris, power plant trash and sludge contaminated with solvents, PCB contaminated soil, solvent-contaminated uranium mill-tailings, and solvent and PCB-contaminated sludge and trash. Over 70 test runs have been performed using the pilot VAC*TRAX system, with more than 80% of the tests using mixed waste as the feed material

  17. Direct thermal dyes

    Science.gov (United States)

    Ehlinger, Edward

    1990-07-01

    Direct thermal dyes are members of a class of compounds referred to in the imaging industry as color formers or leuco dyes. The oldest members of that class have simple triarylmethane structures, and have been employed for years in various dyeing applications. More complex triarylmethane compounds, such as phthalides and fluorans, are now used in various imaging systems to produce color. Color is derived from all of these compounds via the same mechanism, on a molecular level. That is, an event of activation produces a highly resonating cationic system whose interaction with incident light produces reflected light of a specific color. The activation event in the case of a direct thermal system is the creation of a melt on the paper involving dye and an acidic developer. The three major performance parameters in a thermal system are background color, image density, and image stability. The three major dye physical parameters affecting thermal performance are chemical constituency, purity, and particle size. Those dyes having the best combination of characteristics which can also be manufactured economically dominate the marketplace. Manufacturing high performance dyes for the thermal market involves multi-step, convergent reaction sequences performed on large scale. Intermediates must be manufactured at the right time, and at the right quality to be useful.

  18. Experimental Study on Methane Desorption from Lumpy Coal under the Action of Hydraulic and Thermal

    Directory of Open Access Journals (Sweden)

    Dong Zhao

    2018-01-01

    Full Text Available Moisture and thermal are the key factors for influencing methane desorption during CBM exploitation. Using high-pressure water injection technology into coalbed, new fractures and pathways are formed to transport methane. A phenomenon of water-inhibiting gas flow existed. This study is focused on various water pressures impacted on gas-adsorbed coal samples, and then the desorption capacity could be revealed under different conditions. And the results are shown that methane desorption capacity was decreased with the increase in water pressure at room temperature and the downtrend would be steady until water pressure was large enough. Heating could promote gas desorption capacity effectively, with the increasing of water injection pressures, and the promotion of thermal on desorption became more obvious. These results are expected to provide a clearer understanding of theoretical efficiency of heat water or steam injection into coalbed, and they can provide some theoretical and experimental guidance on CBM production and methane control.

  19. Treating high-mercury-containing lamps using full-scale thermal desorption technology.

    Science.gov (United States)

    Chang, T C; You, S J; Yu, B S; Chen, C M; Chiu, Y C

    2009-03-15

    The mercury content in high-mercury-containing lamps are always between 400 mg/kg and 200,000 mg/kg. This concentration is much higher than the 260 mg/kg lower boundary recommended for the thermal desorption process suggested by the US Resource Conservation and Recovery Act. According to a Taiwan EPA survey, about 4,833,000 cold cathode fluorescent lamps (CCFLs), 486,000 ultraviolet lamps and 25,000 super high pressure mercury lamps (SHPs) have been disposed of in the industrial waste treatment system, producing 80, 92 and 9 kg-mercury/year through domestic treatment, offshore treatment and air emissions, respectively. To deal with this problem we set up a full-scale thermal desorption process to treat and recover the mercury from SHPs, fluorescent tube tailpipes, fluorescent tubes containing mercury-fluorescent powder, and CCFLs containing mercury-fluorescent powder and monitor the use of different pre-heating temperatures and desorption times. The experimental results reveal that the average thermal desorption efficiency of SHPs and fluorescent tube tailpipe were both 99.95%, while the average thermal desorption efficiencies of fluorescent tubes containing mercury-fluorescent powder were between 97% and 99%. In addition, a thermal desorption efficiency of only 69.37-93.39% was obtained after treating the CCFLs containing mercury-fluorescent powder. These differences in thermal desorption efficiency might be due to the complexity of the mercury compounds contained in the lamps. In general, the thermal desorption efficiency of lamps containing mercury-complex compounds increased with higher temperatures.

  20. Kinetics Study of Gas Pollutant Adsorption and Thermal Desorption on Silica Gel

    Directory of Open Access Journals (Sweden)

    Rong A

    2017-06-01

    Full Text Available Silica gel is a typical porous desiccant material. Its adsorption performance for gaseous air pollutants was investigated to determine its potential contribution to reducing such pollutants. Three gaseous air pollutants, toluene, carbon dioxide, and methane, were investigated in this paper. A thermogravimetric analyzer was used to obtain the equilibrium adsorption capacity of gases on single silica gel particles. The silica gel adsorption capacity for toluene is much higher than that for carbon dioxide and methane. To understand gas pollutant thermal desorption from silica gel, the thermogravimetric analysis of toluene desorption was conducted with 609 ppm toluene vapor at 313 K, 323 K, and 333 K. The overall regeneration rate of silica gel was strongly dependent on temperature and the enthalpy of desorption. The gas pollutant adsorption performance and thermal desorption on silica gel material may be used to estimate the operating and design parameters for gas pollutant adsorption by desiccant wheels.

  1. Decomposition of thin titanium deuteride films: thermal desorption kinetics studies combined with microstructure analysis

    NARCIS (Netherlands)

    Lisowski, W.F.; Keim, Enrico G.; Kaszkur, Zbigniew; Smithers, M.A.; Smithers, Mark A.

    2008-01-01

    The thermal evolution of deuterium from thin titanium films, prepared under UHV conditions and deuterated in situ at room temperature, has been studied by means of thermal desorption mass spectrometry (TDMS) and a combination of scanning electron microscopy (SEM), transmission electron microscopy

  2. Thermal desorption remediation in relation to landfill disposal at isolated sites in northern Alberta

    International Nuclear Information System (INIS)

    Walker, G.; Henze, M.; Fernuik, N.; MacKinnon, B.; Nelson, D.

    2005-01-01

    Thermal desorption (TD) involves the application of heat to organic-contaminated soil to release and thermally destruct contaminants using high temperatures. An overview of the technique used in the remediation of diesel-contaminated sites was presented. The paper was divided into 2 parts, the first of which provided an overview of TD at 2 electric company sites with a total of 29,000 tonnes of diesel-contaminated soil. Site contamination occurred mainly through the loading, storage and dispensing of diesel fuel. Petroleum lubricants, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), glycols and metals were among the other contaminants. Remediation work was comprised of dig and dump (DD) or thermal desorption (TD) treatment of contaminated soils as well as the removal of underground facilities including concrete foundations, screw anchors, storage tanks, pipelines and grounding grids. The TD process, and productivity with both clay and sand soil types was reviewed, and an analysis of direct, indirect and total costs was presented. Issues concerning planning, production rates, practical field experience and quality control procedures were discussed, in addition to limitations such the treatment's inability to remediate metals, sensitivity to soil water content, and water demands for soil processing. The second section described the role of TD in a staged remediation for 46,000 tonnes of diesel-contaminated soil at Fox Lake, a remote northern community accessible by winter road and ice bridges. The challenges of ice bridge construction and maintenance, excavation backfilling and soil transport at low temperature were reviewed. An outline of consultation processes with First Nations was presented, as well as details of site operations and soil hauling, truck restrictions and coordination over the ice bridge, alternate backfill sources, and TD soil treatment of the contaminated soil. 2 tabs

  3. Leidenfrost Phenomenon-assisted Thermal Desorption (LPTD) and Its Application to Open Ion Sources at Atmospheric Pressure Mass Spectrometry

    Science.gov (United States)

    Saha, Subhrakanti; Chen, Lee Chuin; Mandal, Mridul Kanti; Hiraoka, Kenzo

    2013-03-01

    This work describes the development and application of a new thermal desorption technique that makes use of the Leidenfrost phenomenon in open ion sources at atmospheric pressure for direct mass spectrometric detection of ultratrace levels of illicit, therapeutic, and stimulant drugs, toxicants, and peptides (molecular weight above 1 kDa) in their unaltered state from complex real world samples without or with minor sample pretreatment. A low temperature dielectric barrier discharge ion source was used throughout the experiments and the analytical figures of merit of this technique were investigated. Further, this desorption technique coupled with other ionization sources such as electrospray ionization (ESI) and dc corona discharge atmospheric pressure chemical ionization (APCI) in open atmosphere was also investigated. The use of the high-resolution `Exactive Orbitrap' mass spectrometer provided unambiguous identification of trace levels of the targeted compounds from complex mixtures and background noise; the limits of detection for various small organic molecules and peptides treated with this technique were at the level of parts per trillion and 10-9 M, respectively. The high sensitivity of the present technique is attributed to the spontaneous enrichment of analyte molecules during the slow evaporation of the solvent, as well as to the sequential desorption of molecules from complex mixtures based on their volatilities. This newly developed desorption technique is simple and fast, while molecular ions are observed as the major ions.

  4. Thermal Effect on the Structural, Electrical, and Optical Properties of In-Line Sputtered Aluminum Doped Zinc Oxide Films Explored with Thermal Desorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Shang-Chou Chang

    2014-01-01

    Full Text Available This work investigates the thermal effect on the structural, electrical, and optical properties of aluminum doped zinc oxide (AZO films. The AZO films deposited at different temperatures were measured using a thermal desorption system to obtain their corresponding thermal desorption spectroscopy (TDS. In addition to obtaining information of thermal desorption, the measurement of TDS also has the effect of vacuum annealing on the AZO films. The results of measuring TDS imply part of the doped aluminum atoms do not stay at substituted zinc sites in AZO films. The (002 preferential direction of the AZO films in X-ray diffraction spectra shifts to a lower angle after measurement of TDS. The grain size grows and surface becomes denser for all AZO films after measurement of TDS. The carrier concentration, mobility, and average optical transmittance increase while the electrical resistivity decreases for AZO films after measurement of TDS. These results indicate that the AZO films deposited at 200°C are appropriate selections if the AZO films are applied in device fabrication of heat-produced process.

  5. Surface Structures and Thermal Desorption Behaviors of Cyclopentanethiol Self-Assembled Monolayers on Au(111)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hun Gu; Kim, You Young; Park, Tae Sun; Noh, Jae Geun [Hanyang University, Seoul (Korea, Republic of); Park, Joon B. [Chonbuk National University, Jeonju (Korea, Republic of); Ito, Eisuke; Hara, Masahiko [RIKEN-HYU Collaboration Center, Saitama (Japan)

    2011-04-15

    The surface structures, adsorption conditions, and thermal desorption behaviors of cyclopentanethiol (CPT) self-assembled monolayers (SAMs) on Au(111) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). STM imaging revealed that although the adsorption of CPT on Au(111) at room temperature generates disordered SAMs, CPT molecules at 50 .deg. C formed well-ordered SAMs with a (2√3 x √5)R41{sup .}deg. packing structure. XPS measurements showed that CPT SAMs at room temperature were formed via chemical reactions between the sulfur atoms and gold surfaces. TDS measurements showed two dominant TD peaks for the decomposed fragments (C{sub 5}H{sub 9} {sup +}, m/e = 69) generated via C-S bond cleavage and the parent molecular species (C{sub 5}H{sub 9}SH{sup +}, m/e = 102) derived from a recombination of the chemisorbed thiolates and hydrogen atoms near 440 K. Interestingly, dimerization of sulfur atoms in n-alkanethiol SAMs usually occurs during thermal desorption and the same reaction did not happen for CPT SAMs, which may be due to the steric hindrance of cyclic rings of the CPT molecules. In this study, we demonstrated that the alicyclic ring of organic thiols strongly affected the surface structure and thermal desorption behavior of SAMs, thus providing a good method for controlling chemical and physical properties of organic thiol SAMs.

  6. Surface Structures and Thermal Desorption Behaviors of Cyclopentanethiol Self-Assembled Monolayers on Au(111)

    International Nuclear Information System (INIS)

    Kang, Hun Gu; Kim, You Young; Park, Tae Sun; Noh, Jae Geun; Park, Joon B.; Ito, Eisuke; Hara, Masahiko

    2011-01-01

    The surface structures, adsorption conditions, and thermal desorption behaviors of cyclopentanethiol (CPT) self-assembled monolayers (SAMs) on Au(111) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). STM imaging revealed that although the adsorption of CPT on Au(111) at room temperature generates disordered SAMs, CPT molecules at 50 .deg. C formed well-ordered SAMs with a (2√3 x √5)R41".deg. packing structure. XPS measurements showed that CPT SAMs at room temperature were formed via chemical reactions between the sulfur atoms and gold surfaces. TDS measurements showed two dominant TD peaks for the decomposed fragments (C_5H_9 "+, m/e = 69) generated via C-S bond cleavage and the parent molecular species (C_5H_9SH"+, m/e = 102) derived from a recombination of the chemisorbed thiolates and hydrogen atoms near 440 K. Interestingly, dimerization of sulfur atoms in n-alkanethiol SAMs usually occurs during thermal desorption and the same reaction did not happen for CPT SAMs, which may be due to the steric hindrance of cyclic rings of the CPT molecules. In this study, we demonstrated that the alicyclic ring of organic thiols strongly affected the surface structure and thermal desorption behavior of SAMs, thus providing a good method for controlling chemical and physical properties of organic thiol SAMs

  7. ECO LOGIC INTERNATIONAL GAS-PHASE CHEMICAL REDUCTION PROCESS - THE THERMAL DESORPTION UNIT - APPLICATIONS ANALYSIS REPORT

    Science.gov (United States)

    ELI ECO Logic International, Inc.'s Thermal Desorption Unit (TDU) is specifically designed for use with Eco Logic's Gas Phase Chemical Reduction Process. The technology uses an externally heated bath of molten tin in a hydrogen atmosphere to desorb hazardous organic compounds fro...

  8. Photon-induced Processing of Interstellar Ices in the Laboratory. Focus on Their Non-thermal Desorption.

    Science.gov (United States)

    Martin-Domenech, Rafael; Munoz Caro, Guillermo; Cruz-Diaz, Gustavo A.; Oberg, Karin I.

    2018-06-01

    Some of the processes that take place in the interstellar medium (ISM)can be simulated in laboratories on Earth under astrophysically relevant conditions. For example, the energetic processing of the ice mantles that accrete on top of dust grains in the coldest regions of the ISM, leading to the production of new species and their desorption to the gas phase. In particular, observation of complex organic molecules (COMs) in cold interstellar environments stress the need for not only a solid state formation but also for non-thermal desorption mechanisms that can account for the observed abundances in regions where thermal desorption is inhibited. Laboratory Astrophysics can be used to test different non-thermal desorption processes and extract yields than can be extrapolated to the astrophysical scenario with theoretical models. 0th generation COMs like CH3OH and H2CO can be formed at very low temperatures. In this talk, we present laboratory simulations of the UV photoprocessing of a binary ice mixture composed by water (the main component of astrophysical ices) and methane. Formation of CO, CO2, CH3OH and H2CO was confirmed by IR spectroscopy and subsequent TPD. At the same time, photodesorption of CO and H2CO was detected by means of a Quadrupole Mass Spectrometer, with yields on the order of 10-4 and 10-5 molecules per incident photon, respectively. In general, photodesorption can take place through a direct mechanism, where the absorbing molecule (or its photofragments) are desorbed; or through an indirect mechanism where the absorbed energy is transferred to a surface molecule which is the one finally desorbing. In the case of photoproducts, the evolution of the photodesorption yield gives information on the photodesorption mechanism: a constant photodesorption yield is observed when the photoproducts are desorbed right after their formation; while an increasing yield is measured when the photoproducts are desorbed later after energy transfer from another

  9. Thermal desorption of deuterium from polycrystalline nickel pre-implanted with helium

    International Nuclear Information System (INIS)

    Shi, S.Q.; Abramov, E.; Thompson, D.A.

    1990-01-01

    The thermal desorption technique has been used to study the trapping of deuterium atoms in high-purity polycrystalline nickel pre-implanted with helium for 1 x 10 19 to 5 x 10 20 ions/m 2 . The effect of post-implantation annealing at 703 K and 923 K on the desorption behavior was investigated. Measured values of the total amount of detrapped deuterium (Q T ) and helium concentration were used in a computer simulation of the desorption curve. It was found that the simulation using one or two discrete trap energies resulted in an inadequate fit between the simulated and the measured data. Both experimental and simulation results are explained using a stress-field trapping model. The effective binding energy, E b eff , was estimated to be in the range of 0.4-0.6 eV. Deuterium charging was found to stimulate a release of helium at a relatively low temperature

  10. Thermal desorption of formamide and methylamine from graphite and amorphous water ice surfaces

    Science.gov (United States)

    Chaabouni, H.; Diana, S.; Nguyen, T.; Dulieu, F.

    2018-04-01

    Context. Formamide (NH2CHO) and methylamine (CH3NH2) are known to be the most abundant amine-containing molecules in many astrophysical environments. The presence of these molecules in the gas phase may result from thermal desorption of interstellar ices. Aims: The aim of this work is to determine the values of the desorption energies of formamide and methylamine from analogues of interstellar dust grain surfaces and to understand their interaction with water ice. Methods: Temperature programmed desorption (TPD) experiments of formamide and methylamine ices were performed in the sub-monolayer and monolayer regimes on graphite (HOPG) and non-porous amorphous solid water (np-ASW) ice surfaces at temperatures 40-240 K. The desorption energy distributions of these two molecules were calculated from TPD measurements using a set of independent Polanyi-Wigner equations. Results: The maximum of the desorption of formamide from both graphite and ASW ice surfaces occurs at 176 K after the desorption of H2O molecules, whereas the desorption profile of methylamine depends strongly on the substrate. Solid methylamine starts to desorb below 100 K from the graphite surface. Its desorption from the water ice surface occurs after 120 K and stops during the water ice sublimation around 150 K. It continues to desorb from the graphite surface at temperatures higher than160 K. Conclusions: More than 95% of solid NH2CHO diffuses through the np-ASW ice surface towards the graphitic substrate and is released into the gas phase with a desorption energy distribution Edes = 7460-9380 K, which is measured with the best-fit pre-exponential factor A = 1018 s-1. However, the desorption energy distribution of methylamine from the np-ASW ice surface (Edes = 3850-8420 K) is measured with the best-fit pre-exponential factor A = 1012 s-1. A fraction of solid methylamine monolayer of roughly 0.15 diffuses through the water ice surface towards the HOPG substrate. This small amount of methylamine

  11. Investigation of hydrogen-deformation interactions in β-21S titanium alloy using thermal desorption spectroscopy

    International Nuclear Information System (INIS)

    Tal-Gutelmacher, E.; Eliezer, D.; Boellinghaus, Th.

    2007-01-01

    The focus of this paper is the investigation of the combined influence of hydrogen and pre-plastic deformation on hydrogen's absorption/desorption behavior, the microstructure and microhardness of a single-phased β-21S alloy. In this study, thermal desorption analyses (TDS) evaluation of various desorption and trapping parameters provide further insight on the relationships between hydrogen absorption/desorption processes and deformation, and their mutual influence on the microstructure and the microhardness of β-21S alloy. TDS spectra were supported by other experimental techniques, such as X-ray diffraction, scanning and transmission electron microscopy, hydrogen quantity analyses and microhardness tests. Pre-plastic deformation, performed before the electrochemical hydrogenation of the alloy, increased significantly the hydrogen absorption capacity. Its influence was also evident on the notably expanded lattice parameter of β-21S alloy after hydrogenation. However, no hydride precipitation was observed. An interesting softening effect of the pre-deformed hydrogenated alloy was revealed by microhardness tests. TDS demonstrated the significant effect of pre-plastic deformation on the hydrogen evolution process. Hydrogen desorption temperature and the activation energy for hydrogen release increased, additional trap states were observed and the amount of desorbed hydrogen decreased

  12. Design and construction of thermal desorption measurement system for tritium contained materials

    International Nuclear Information System (INIS)

    Hara, M.; Hatano, Y.; Calderoni, P.; Shimada, M.

    2014-01-01

    The dual-mode thermal desorption analysis system was designed and built in Idaho National Laboratory (INL) to examine the evolution of the hydrogen isotope gas from materials. The system is equipped with a mass spectrometer for stable hydrogen isotopes and an ionization chamber for tritium components. The performance of the system built was tested with using tritium contained materials. The evolution of tritiated gas species from contaminated materials was measured successfully by using the system. (author)

  13. Treatment of Y-12 storm sewer sediments and DARA soils by thermal desorption

    International Nuclear Information System (INIS)

    Morris, M.I.; Shealy, S.E.

    1995-01-01

    The 1992 Oak Ridge Reservation Federal Facilities Compliance Agreement (FFCA) listed a number of mixed wastes, subject to land disposal restrictions (LDR), for which no treatment method had been identified, and required DOE to develop strategies for treatment and ultimate disposal of those wastes. This paper presents the results of a program to demonstrate that thermal desorption can remove both organics and mercury from two mixed wastes from the DOE Y-12 facility in Oak Ridge, Tennessee. The first waste, the Y-12 Storm Sewer Sediments (SSSs) was a sediment generated from upgrades to the plant storm sewer system. This material contained over 4 percent mercury, 2 percent uranium and 350 mg/kg polychlorinated biphenyls (PCBs). Leachable mercury exceeded toxicity characteristic leaching procedure (TCLP) and LDR criteria. The second waste, the Disposal Area Remedial Action (DARA) Soils, are contaminated with uranium, mercury and PCBs. This treatability study included bench-scale testing of a thermal desorption process. Results of the testing showed that, for the SSSs, total mercury could be reduced to 120 mg/kg by treatment at 600 degrees C, which is at the high end of the temperature range for typical thermal desorption systems. Leachable TCLP mercury was less than 50 μg/L and PCBs were below 2 mg/kg. Treatment of the DARA Soils at 450 degrees C for 10 minutes resulted in residual PCBs of 0.6 to 3.0 mg/kg. This is too high (goal < 2mg/kg) and higher treatment temperatures are needed. The testing also provided information on the characteristics and quantities of residuals from the thermal desorption process

  14. VAC*TRAX - thermal desorption for mixed wastes

    Energy Technology Data Exchange (ETDEWEB)

    McElwee, M.J.; Palmer, C.R. [RUST-Clemson Technical Center, Anderson, SC (United States)

    1995-10-01

    The patented VAC*TRAX process was designed in response to the need to remove organic constituents from mixed waste, waste that contains both a hazardous (RCRA or TSCA regulated) component and a radioactive component. Separation of the mixed waste into its hazardous and radioactive components allows for ultimate disposal of the material at existing, permitted facilities. The VAC*TRAX technology consists of a jacketed vacuum dryer followed by a condensing train. Solids are placed in the dryer and indirectly heated to temperatures as high as 2600{degrees}C, while a strong vacuum (down to 50 mm Hg absolute pressure) is applied to the system and the dryer is purged with a nitrogen carrier gas. The organic contaminants in the solids are thermally desorbed, swept up in the carrier gas and into the condensing train where they are cooled and recovered. The dryer is fitted with a filtration system that keeps the radioactive constituents from migrating to the condensate. As such, the waste is separated into hazardous liquid and radioactive solid components, allowing for disposal of these streams at a permitted incinerator or a radioactive materials landfill, respectively. The VAC*TRAX system is designed to be highly mobile, while minimizing the operational costs with a simple, robust process. These factors allow for treatment of small waste streams at a reasonable cost.

  15. Thermal desorption spectroscopy of boron/carbon films after keV deuterium irradiation

    International Nuclear Information System (INIS)

    Yamaki, T.; Gotoh, Y.; Ando, T.; Jimbou, R.; Ogiwara, N.; Saidoh, M.

    1994-01-01

    Thermal desorption spectroscopy (TDS) of D 2 and CD 4 was done on boron/carbon films (B/(B+C)=0-74%), after 3 keV D 3 + irradiation to 4.5x10 17 D/cm 2 at 473 K. The D 2 desorption peaks were observed at 1050, 850 and 650 K. For a sputter B/C film (0%), only the 1050 K peak was observed. With increasing boron concentration to 3%, a sharp peak appeared at 850 K, the intensity of which was found to increase with increasing boron concentration to 23%, and then to decrease at 74%. The 650 K shoulder, which was observed for high boron concentration specimens, was speculated to be deuterium trapped by boron atoms in the boron clusters. The relative amount of CD 4 desorption was found to decrease with increasing boron concentration, which was attributed to the decrease in the trapped deuterium concentration in the implantation layer at temperatures at which CD 4 desorption proceeds. ((orig.))

  16. Modelling deuterium release during thermal desorption of D{sup +}-irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Poon, M. [University of Toronto Institute for Aerospace Studies, Toronto, ON, M3H 5T6 (Canada); Haasz, A.A. [University of Toronto Institute for Aerospace Studies, Toronto, ON, M3H 5T6 (Canada)], E-mail: tonyhaasz@utias.utoronto.ca; Davis, J.W. [University of Toronto Institute for Aerospace Studies, Toronto, ON, M3H 5T6 (Canada)

    2008-03-15

    Thermal desorption profiles were modelled based on SIMS measurements of implantation profiles and using the multi-trap diffusion code TMAP7 [G.R. Longhurst, TMAP7: Tritium Migration Analysis Program, User Manual, Idaho National Laboratory, INEEL/EXT-04-02352 (2004)]. The thermal desorption profiles were the result of 500 eV/D{sup +} irradiations on single crystal tungsten at 300 and 500 K to fluences of 10{sup 22}-10{sup 24} D{sup +}/m{sup 2}. SIMS depth profiling was performed after irradiation to obtain the distribution of trapped D within the top 60 nm of the surface. Thermal desorption spectroscopy (TDS) was performed subsequently to obtain desorption profiles and to extract the total trapped D inventory. The SIMS profiles were calibrated to give D concentrations. To account for the total trapped D inventory measured by TDS, SIMS depth distributions were used in the near-surface (surface to 30 nm), NRA measurements [V.Kh. Alimov, J. Roth, M. Mayer, J. Nucl. Mater. 337-339 (2005) 619] were used in the range 1-7 {mu}m, and a linear drop in the D distribution was assumed in the intermediate sub-surface region ({approx}30 nm to 1 {mu}m). Traps were assumed to be saturated so that the D distribution also represented the trap distribution. Three trap energies, 1.07 {+-} 0.03, 1.34 {+-} 0.03 and 2.1 {+-} 0.05 eV were required to model the 520, 640 and 900 K desorption peaks, respectively. The 1.34 and 1.07 eV traps correspond to trapping of a first and second D atom at a vacancy, respectively, while the 2.1 eV trap corresponds to atomic D trapping at a void. A fourth trap energy of 0.65 eV was used to fit the 400 K desorption peak observed by Quastel et al. [A.D. Quastel, J.W. Davis, A.A. Haasz, R.G. Macaulay-Newcombe, J. Nucl. Mater. 359 (2006) 8].

  17. Non-thermal desorption from interstellar dust grains via exothermic surface reactions

    Science.gov (United States)

    Garrod, R. T.; Wakelam, V.; Herbst, E.

    2007-06-01

    Aims:The gas-phase abundance of methanol in dark quiescent cores in the interstellar medium cannot be explained by gas-phase chemistry. In fact, the only possible synthesis of this species appears to be production on the surfaces of dust grains followed by desorption into the gas. Yet, evaporation is inefficient for heavy molecules such as methanol at the typical temperature of 10 K. It is necessary then to consider non-thermal mechanisms for desorption. But, if such mechanisms are considered for the production of methanol, they must be considered for all surface species. Methods: Our gas-grain network of reactions has been altered by the inclusion of a non-thermal desorption mechanism in which the exothermicity of surface addition reactions is utilized to break the bond between the product species and the surface. Our estimated rate for this process derives from a simple version of classical unimolecular rate theory with a variable parameter only loosely constrained by theoretical work. Results: Our results show that the chemistry of dark clouds is altered slightly at times up to 106 yr, mainly by the enhancement in the gas-phase abundances of hydrogen-rich species such as methanol that are formed on grain surfaces. At later times, however, there is a rather strong change. Instead of the continuing accretion of most gas-phase species onto dust particles, a steady-state is reached for both gas-phase and grain-surface species, with significant abundances for the former. Nevertheless, most of the carbon is contained in an undetermined assortment of heavy surface hydrocarbons. Conclusions: The desorption mechanism discussed here will be better constrained by observational data on pre-stellar cores, where a significant accretion of species such as CO has already occurred.

  18. Triple sorbent thermal desorption/gas chromatography/mass spectrometry determination of vapor phase organic contaminants

    International Nuclear Information System (INIS)

    Ma, C.Y.; Skeen, J.T.; Dindal, A.B.; Higgins, C.E.; Jenkins, R.A.

    1994-05-01

    A thermal desorption/ps chromatography/mass spectrometry (TD/GC/MS) has been evaluated for the determination of volatile organic compounds (VOCS) in vapor phase samples using Carbosieve S-III/Carbotrap/Carotrap C triple sorbent traps (TST) similar to those available from a commercial source. The analysis was carried out with a Hewlett-Packard 5985A or 5995 GC/MS system with a modified injector to adapt an inhouse manufactured short-path desorber for transferring desorbate directly onto a cryofocusing loop for subsequent GC/MS analysis. Vapor phase standards generated from twenty six compounds were used for method validation, including alkanes, alkyl alcohols, alkyl ketones, and alkyl nitrites, a group of representative compounds that have previously been identified in a target airborne matrix. The method was validated based on the satisfactory results in terms of reproducibility, recovery rate, stability, and linearity. A relative, standard deviation of 0.55 to 24.3 % was obtained for the entire TD process (generation of gas phase standards, spiking the standards on and desorbing from TST) over a concentration range of 20 to 500 ng/trap. Linear correlation coefficients for the calibration curves as determined ranged from 0.81 to 0.99 and limits of detection ranged from 3 to 76 ng. For a majority of standards, recoveries of greater than 90% were observed. For three selected standards spiked on TSTS, minimal loss (10 to 22%) was observed after storing the spiked in, a 4 degree C refrigerator for 29 days. The only chromatographable artifact observed was a 5% conversion of isopropanol to acetone. The validated method been successfully applied, to the determination of VOCs collected from various emission sources in a diversified concentration range

  19. Cold vapor-solid phase microextraction using amalgamation in different Pd-based substrates combined with direct thermal desorption in a modified absorption cell for the determination of Hg by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Romero, Vanesa; Costas-Mora, Isabel; Lavilla, Isela; Bendicho, Carlos

    2011-01-01

    In this work, different Pd-based substrates (i.e. Pd wire, Pd-coated stainless steel wire and Pd-coated SiO 2 ) are tried for microextraction of Hg prior to its release into a modified quartz T-cell so as to develop a cost-effective, sensitive and easy-to-handle coupling between solid-phase microextraction (SPME) and atomic absorption spectrometry. The new design allows a direct sample injection from the SPME device into a quartz T-cell thus avoiding analyte dilution. Mercury amalgamation onto a Pd wire provided the best performance in respect to sensitivity and fiber lifetime, but Pd wires could not be implemented in the SPME device due to their poor mechanical characteristics. On the contrary, Pd-coated SiO 2 fibers could be easily adapted to the typical sampling device used for SPME. Narrow time-dependent absorption signal profiles that could be integrated within 25 s were obtained. The detection limit was 90 pg mL -1 of Hg, and the repeatability expressed as relative standard deviation was 4.3%.

  20. Thermal soil desorption for total petroleum hydrocarbon testing on gas chromatographs

    International Nuclear Information System (INIS)

    Mott, J.

    1995-01-01

    Testing for total petroleum hydrocarbons (TPH) is one of the most common analytical tests today. A recent development in chromatography incorporates Thermal Soil Desorption technology to enable analyses of unprepared soil samples for volatiles such as BTEX components and semi-volatiles such as diesel, PCBs, PAHs and pesticides in the same chromatogram, while in the field. A gas chromatograph is the preferred method for determining TPH because the column in a GC separates the individual hydrocarbons compounds such as benzene and toluene from each other and measures each individually. A GC analysis will determine not only the total amount of hydrocarbon, but also whether it is gasoline, diesel or another compound. TPH analysis with a GC is typically conducted with a Flame Ionization Detector (FID). Extensive field and laboratory testing has shown that incorporation of a Thermal Soil Desorber offers many benefits over traditional analytical testing methods such as Headspace, Solvent Extraction, and Purge and Trap. This paper presents the process of implementing Thermal Soil Desorption in gas chromatography, including procedures for, and advantages of faster testing and analysis times, concurrent volatile and semi-volatile analysis, minimized sample manipulation, single gas (H 2 ) operation, and detection to the part-per billion levels

  1. Direct pathway for sticking/desorption of H2 on Si(100)

    DEFF Research Database (Denmark)

    Kratzer, Peter; Hammer, Bjørk; Nørskov, Jens Kehlet

    1995-01-01

    The energetics of H2 interacting with the Si(100) surface is studied by means of ab initio total-energy calculations within the framework of density-functional theory. We find a direct desorption pathway from the monohydride phase that is compatible with experimental activation energies and demon......The energetics of H2 interacting with the Si(100) surface is studied by means of ab initio total-energy calculations within the framework of density-functional theory. We find a direct desorption pathway from the monohydride phase that is compatible with experimental activation energies...... and demonstrate the importance of substrate relaxation for this process. Both the transition state configuration and the barrier height depend crucially on the degree of buckling of the Si dimers on the Si(100) surface. The adsorption barrier height on the clean surface is governed by the buckling via its...

  2. Low-temperature thermal reduction of graphene oxide: In situ correlative structural, thermal desorption, and electrical transport measurements

    Science.gov (United States)

    Lipatov, Alexey; Guinel, Maxime J.-F.; Muratov, Dmitry S.; Vanyushin, Vladislav O.; Wilson, Peter M.; Kolmakov, Andrei; Sinitskii, Alexander

    2018-01-01

    Elucidation of the structural transformations in graphene oxide (GO) upon reduction remains an active and important area of research. We report the results of in situ heating experiments, during which electrical, mass spectrometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) measurements were carried out correlatively. The simultaneous electrical and temperature programmed desorption measurements allowed us to correlate the onset of the increase in the electrical conductivity of GO by five orders of magnitude at about 150 °C with the maxima of the rates of desorption of H2O, CO, and CO2. Interestingly, this large conductivity change happens at an intermediate level of the reduction of GO, which likely corresponds to the point when the graphitic domains become large enough to enable percolative electronic transport. We demonstrate that the gas desorption is intimately related to (i) the changes in the chemical structure of GO detected by XPS and Raman spectroscopy and (ii) the formation of nanoscopic holes in GO sheets revealed by TEM. These in situ observations provide a better understanding of the mechanism of the GO thermal reduction.

  3. Trace level detection of explosives in solution using leidenfrost phenomenon assisted thermal desorption ambient mass spectrometry.

    Science.gov (United States)

    Saha, Subhrakanti; Mandal, Mridul Kanti; Chen, Lee Chuin; Ninomiya, Satoshi; Shida, Yasuo; Hiraoka, Kenzo

    2013-01-01

    The present paper demonstrates the detection of explosives in solution using thermal desorption technique at a temperature higher than Leidenfrost temperature of the solvent in combination with low temperature plasma (LTP) ionization. Leidenfrost temperature of a solvent is the temperature above which the solvent droplet starts levitation instead of splashing when placed on a hot metallic surface. During this desorption process, slow and gentle solvent evaporation takes place, which leads to the pre-concentration of less-volatile explosive molecules in the droplet and the explosive molecules are released at the last moment of droplet evaporation. The limits of detection for explosives studied by using this thermal desorption LTP ionization method varied in a range of 1 to 10 parts per billion (ppb) using a droplet volume of 20 μL (absolute sample amount 90-630 fmol). As LTP ionization method was applied and ion-molecule reactions took place in ambient atmosphere, various ion-molecule adduct species like [M+NO2](-), [M+NO3](-), [M+HCO3](-), [M+HCO4](-) were generated together with [M-H](-) peak. Each peak was unambiguously identified using 'Exactive Orbitrap' mass spectrometer in negative ionization mode within 3 ppm deviation compared to its exact mass. This newly developed technique was successfully applied to detect four explosives contained in the pond water and soil sample with minor sample pre-treatment and the explosives were detected with ppb levels. The present method is simple, rapid and can detect trace levels of explosives with high specificity from solutions.

  4. Thermal imitators with single directional invisibility

    Science.gov (United States)

    Wang, Ruizhe; Xu, Liujun; Huang, Jiping

    2017-12-01

    Thermal metamaterials have been intensively studied during the past years to achieve the long-standing dream of invisibility, illusion, and other inconceivable thermal phenomena. However, many thermal metamaterials can only exhibit omnidirectional thermal response, which take on the distinct feature of geometrical isotropy. In this work, we theoretically design and experimentally fabricate a pair of thermal imitators by applying geometrical anisotropy provided by elliptical/ellipsoidal particles and layered structures. This pair of thermal imitators possesses thermal invisibility in one direction, while having thermal opacity in other directions. This work may open a gate in designing direction-dependent thermal metamaterials.

  5. Demonstration of a batch vacuum thermal desorption process on hazardous and mixed waste

    International Nuclear Information System (INIS)

    Palmer, C.R.; McElwee, M.; Meyers, G.

    1995-01-01

    Many different waste streams have been identified at Department of Energy (DOE) facilities as having both hazardous organic and radioactive contaminants. There is presently only one permitted facility in which to manage these materials, and that facility has only limited capacity to process solid wastes. Over the past two years, Rust has been pilot testing a new thermal desorption process that is very well suited to these wastes, and has begun permitting and design of a unit for commercial operation. This paper presents both historic and recent pilot test data on the treatment of hazardous and mixed waste. Also described is the commercial unit. Rust's patented VAC*TRAX technology takes advantage of high vacuum to reduced operating temperature for the thermal desorption of organic contaminants from waste soils, sludges and other contaminated solids. This allows for economical thermal separation on relatively small sites (30 to 5,000 m 3 of waste). VAC*TRAX employs indirect heating; this, combined with a very low carrier gas flow, results in a vent flow rate of approximately 1 m 3 /min which allows for the use of control devices that would not be practical with conventional thermal technology. The unit is therefore ideally suited to processing mixed waste, since zero radioactive emissions can be maintained. An additional benefit of the technology is that the low operating temperature allows highly effective separation to be performed well below the degradation point for the solid components of a trash type waste stream, which constitutes a large fraction of the present mixed waste inventory

  6. Helium implanted Eurofer97 characterized by positron beam Doppler broadening and Thermal Desorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, I., E-mail: i.carvalho@m2i.nl [Materials Innovation Institute (M2i), Delft (Netherlands); Schut, H. [Delft University of Technology, Faculty of Applied Sciences, Delft (Netherlands); Fedorov, A.; Luzginova, N. [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Desgardin, P. [CEMHTI-CNRS, 3A Rue de la Férolerie, 45071 Orléans Cedex (France); Sietsma, J. [Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Delft (Netherlands)

    2013-11-15

    Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion and Generation IV fission reactors. To produce irradiation induced defects, Eurofer97 samples were implanted with helium at energies of 500 keV and 2 MeV and doses of 1 × 10{sup 15}–10{sup 16} He/cm{sup 2}, creating atomic displacements in the range 0.07–0.08 dpa. The implantation induced defects were characterized by positron beam Doppler Broadening (DB) and Thermal Desorption Spectroscopy (TDS). Results show that up to ∼600 K peaks that can be attributed to He desorption from overpressured He{sub n}V{sub m} (n > m) clusters and vacancy assisted mechanism in the case of helium in the substitutional position. The temperature range 600–1200 K is related to the formation of larger clusters He{sub n}V{sub m} (n < m). The dissociation of the HeV and the phase transition attributed to a sharp peak in the TDS spectra at 1200 K. Above this temperature, the release of helium from bubbles is observed.

  7. Thermal desorption and bombardment-induced release of deuterium implanted into stainless steels at low energy

    International Nuclear Information System (INIS)

    Farrell, G.; Donnelly, S.E.

    1978-01-01

    Thermal desorption spectra have been obtained for low energy (15-750 eV) deuterons implanted into types 321 and 304 stainless steel, to total fluences in the range 10 13 - 10 17 deuterons/cm 2 . In each case the spectra show a peak at about 350 K, but in the 321 steel there is a second peak in the region of 900 K, the population and peak temperature of which increase with energy. Activation energies of 0.99 and 2.39 eV and a rate constant of 7 x 10 15 /s have been derived for the peaks and it is thought that the first peak corresponds to release from sites close to the surface, while the second peak may be related to trapping at impurities such as Ti. Measurements have also been made of the release of deuterium resulting from post-implantation bombardment with hydrogen ions. It is found that depletion of the first peak in the 321 steel is the result of gas sputtering, but depletion of the second peak is the result of the formation of HD during desorption, while depletion of the peak in the 304 stainless steel also results from HD formation even though this peak is the same as the first peak in the 321 steel. Estimates have also been made of the deuterium self-sputtering cross section at various energies, which show a monotonic decrease as energy increases. (Auth.)

  8. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    International Nuclear Information System (INIS)

    Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

    2015-01-01

    Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 10 26 m −2 ) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min −1 up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h

  9. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    Science.gov (United States)

    Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

    2015-08-01

    Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 1026 m-2) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min-1 up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h.

  10. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Masashi, E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID (United States); Hara, Masanori [Hydrogen Isotope Research Center, University of Toyama, Toyama (Japan); Otsuka, Teppei [Kyushu University, Interdisciplinary Graduate School of Engineering Science, Higashi-ku, Fukuoka (Japan); Oya, Yasuhisa [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Hatano, Yuji [Hydrogen Isotope Research Center, University of Toyama, Toyama (Japan)

    2015-08-15

    Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 10{sup 26} m{sup −2}) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min{sup −1} up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h.

  11. Quantification of Selected Vapour-Phase Compounds using Thermal Desorption-Gas Chromatography

    Directory of Open Access Journals (Sweden)

    McLaughlin DWJ

    2014-12-01

    Full Text Available A robust method for the analysis of selected vapour phase (VP compounds in mainstream smoke (MSS is described. Cigarettes are smoked on a rotary smoking machine and the VP that passes through the Cambridge filter pad collected in a TedlarA¯ bag. On completion of smoking, the bag contents are sampled onto an adsorption tube containing a mixed carbon bed. The tube is subsequently analysed on an automated thermal desorption (TD system coupled to a gas chromatography-flame ionization detector (GC-FID using a PoraPLOT-Q column. Quantification of 14 volatile compounds including the major carbonyls is achieved. Details of the method validation data are included in this paper. This method has been used to analyse the VP of cigarette MSS over a wide range of ‘tar’ deliveries and configurations with excellent repeatability. Results for the University of Kentucky reference cigarette 1R4F are in good agreement with reported values.

  12. A Solid Trap and Thermal Desorption System with Application to a Medical Electronic Nose

    Directory of Open Access Journals (Sweden)

    Xuntao Xu

    2008-11-01

    Full Text Available In this paper, a solid trap/thermal desorption-based odorant gas condensation system has been designed and implemented for measuring low concentration odorant gas. The technique was successfully applied to a medical electronic nose system. The developed system consists of a flow control unit, a temperature control unit and a sorbent tube. The theoretical analysis and experimental results indicate that gas condensation, together with the medical electronic nose system can significantly reduce the detection limit of the nose system and increase the system’s ability to distinguish low concentration gas samples. In addition, the integrated system can remove the influence of background components and fluctuation of operational environment. Even with strong disturbances such as water vapour and ethanol gas, the developed system can classify the test samples accurately.

  13. Operable Unit 7-13/14 in situ thermal desorption treatability study work plan

    International Nuclear Information System (INIS)

    Shaw, P.; Nickelson, D.; Hyde, R.

    1999-01-01

    This Work Plan provides technical details for conducting a treatability study that will evaluate the application of in situ thermal desorption (ISTD) to landfill waste at the Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). ISTD is a form of thermally enhanced vapor vacuum extraction that heats contaminated soil and waste underground to raise its temperature and thereby vaporize and destroy most organics. An aboveground vapor vacuum collection and treatment system then destroys or absorbs the remaining organics and vents carbon dioxide and water to the atmosphere. The technology is a byproduct of an advanced oil-well thermal extraction program. The purpose of the ISTD treatability study is to fill performance-based data gaps relative to off-gas system performance, administrative feasibility, effects of the treatment on radioactive contaminants, worker safety during mobilization and demobilization, and effects of landfill type waste on the process (time to remediate, subsidence potential, underground fires, etc.). By performing this treatability study, uncertainties associated with ISTD as a selected remedy will be reduced, providing a better foundation of remedial recommendations and ultimate selection of remedial actions for the SDA

  14. Atmospheric Pressure-Thermal Desorption (AP-TD)/Electrospray Ionization-Mass Spectrometry for the Rapid Analysis of Bacillus Spores

    Science.gov (United States)

    A technique is described where an atmospheric pressure-thermal desorption (AP-TD) device and electrospray ionization (ESI)-mass spectrometry are coupled and used for the rapid analysis of Bacillus spores in complex matrices. The resulting AP-TD/ESI-MS technique combines the generation of volatile co...

  15. SUPERFUND TREATABILITY CLEARINGHOUSE: TECHNOLOGY DEMONSTRATION OF A THERMAL DESORPTION/UV PHOTOLYSIS PROCESS FOR DECONTAMINATING SOILS CONTAINING HERBICIDE ORANGE

    Science.gov (United States)

    This treatability study report presents the results of laboratory and field tests on the effectiveness of a new decontamination process for soils containing 2,4-D/2,4,5-T and traces of dioxin. The process employs three operations, thermal desorption, condensation and absorp...

  16. DEMONSTRATION BULLETIN: THE ECO LOGIC THERMAL DESORPTION UNIT - MIDDLEGROUND LANDFILL - BAY CITY, MI - ELI ECO LOGIC INTERNATIONAL, INC.

    Science.gov (United States)

    ECO Logic has developed a thermal desorption unit 0"DU) for the treatment of soils contaminated with hazardous organic contaminants. This TDU has been designed to be used in conjunction with Eco Logic's patented gas-phase chemical reduction reactor. The Eco Logic reactor is the s...

  17. Rapid detection of illegal colorants on traditional Chinese pastries through mass spectrometry with an interchangeable thermal desorption electrospray ionization source.

    Science.gov (United States)

    Chao, Yu-Ying; Chen, Yen-Ling; Chen, Wei-Chu; Chen, Bai-Hsiun; Huang, Yeou-Lih

    2018-06-30

    Ambient mass spectrometry using an interchangeable thermal desorption/electrospray ionization source (TD-ESI) is a relatively new technique that has had only a limited number of applications to date. Nevertheless, this direct-analysis technique has potential for wider use in analytical chemistry (e.g., in the rapid direct detection of contaminants, residues, and adulterants on and in food) when operated in dual-working mode (pretreatment-free qualitative screening and conventional quantitative confirmation) after switching to a TD-ESI source from a conventional ESI source. Herein, we describe the benefits and challenges associated with the use of a TD-ESI source to detect adulterants on traditional Chinese pastries (TCPs), as a proof-of-concept for the detection of illegal colorants. While TD-ESI can offer direct (i.e., without any sample preparation) qualitative screening analyses for TCPs with adequate sensitivity within 30 s, the use of TD-ESI for semi-quantification is applicable only for homogeneous matrices (e.g., tang yuan). Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Non-isothermal kinetics of the thermal desorption of mercury from a contaminated soil

    Directory of Open Access Journals (Sweden)

    López, Félix A.

    2014-03-01

    Full Text Available The Almadén mining district (Ciudad Real, Spain was the largest cinnabar (mercury sulphide mine in the world. Its soils have high levels of mercury a consequence of its natural lithology, but often made much worse by its mining history. The present work examines the thermal desorption of two contaminated soils from the Almadén area under non-isothermal conditions in a N2 atmosphere, using differential scanning calorimetry (DSC. DSC was performed at different heating rates between room temperature and 600 °C. Desorption temperatures for different mercury species were determined. The Friedman, Flynn-Wall-Ozawa and Coasts–Redfern methods were employed to determine the reaction kinetics from the DSC data. The activation energy and pre-exponential factor for mercury desorption were calculated.El distrito minero de Almadén (Ciudad Real, España tiene la mayor mina de cinabrio (sulfuro de mercurio del mundo. Sus suelos tienen altos niveles de mercurio como consecuencia de su litología natural, pero a menudo su contenido en mercurio es mucho más alto debido a la historia minera de la zona. Este trabajo examina la desorción térmica de dos suelos contaminados procedentes de Almadén bajo condiciones isotérmicas en atmósfera de N2, empleando calorimetría diferencial de barrido (DSC. La calorimetría se llevó a cabo a diferentes velocidades de calentamiento desde temperatura ambiente hasta 600 °C. Se determinaron las diferentes temperaturas de desorción de las especies de mercurio presentes en los suelos. Para determinar la cinética de reacción a partir de los datos de DSC se utilizaron los métodos de Friedman, Flynn-Wall-Ozawa y Coasts–Redfern. Además se calcularon las energías de activación y los factores pre-exponenciales para la desorción del mercurio.

  19. Thermal desorption spectroscopy of pyrolytic graphite cleavage faces after keV deuterium irradiation at 330-1000 K

    International Nuclear Information System (INIS)

    Gotoh, Y.; Yamaki, T.; Tokiguchi, K.

    1992-01-01

    Thermal desorption spectroscopy (TDS) measurements were made on D 2 and CD 4 from surface layers of pyrolytic graphite cleavage faces after 3 keV D + 3 irradiation to 1.5 x 10 18 D/cm 2 at irradiation temperatures from 330 to 1000 K. Thermal desorption of both D 2 and CD 4 was observed to rise simultaneously at around 700 K. The D 2 peak was found at T m = 900-1000 K, while the CD 4 peak appeared at a lower temperature, 800-840 K. The T m for the D 2 TDS increased, while that for the CD 4 decreased with increasing irradiation temperature. These results obviously indicate that the D 2 desorption is detrapping/recombination limited, while the CD 4 desorption is most likely to be diffusion limited. The amount of thermally desorbed D 2 after the D + irradiation was observed to monotonously decrease as the irradiation temperature was increased from 330 to 1000 K. These tendencies agreed with previous results for the irradiation temperature dependencies of both C1s chemical shift (XPS) and the interlayer spacing, d 002 (HRTEM), on the graphite basal face. (orig.)

  20. Effects of H2O and H2O2 on thermal desorption of tritium from stainless steel

    International Nuclear Information System (INIS)

    Quinlan, M. J.; Shmayda, W. T.; Lim, S.; Salnikov, S.; Chambers, Z.; Pollock, E.; Schroeder, W. U.

    2008-01-01

    Tritiated stainless steel was subjected to thermal desorption at various temperatures, different temperature profiles, and in the presence of different helium carrier gas additives. In all cases the identities of the desorbing tritiated species were characterized as either water-soluble or insoluble. The samples were found to contain 1.1 mCi±0.4 mCi. Approximately ninety-five percent of this activity was released in molecular water-soluble form. Additives of H 2 O or H 2 O 2 to dry helium carrier gas increase the desorption rate and lower the maximum temperature to which the sample must be heated, in order to remove the bulk of the tritium. The measurements validate a method of decontamination of tritiated steel and suggest a technique that can be used to further explore the mechanisms of desorption from tritiated metals. (authors)

  1. Characterisation of Dissolved Organic Carbon by Thermal Desorption - Proton Transfer Reaction - Mass Spectrometry

    Science.gov (United States)

    Materić, Dušan; Peacock, Mike; Kent, Matthew; Cook, Sarah; Gauci, Vincent; Röckmann, Thomas; Holzinger, Rupert

    2017-04-01

    Dissolved organic carbon (DOC) is an integral component of the global carbon cycle. DOC represents an important terrestrial carbon loss as it is broken down both biologically and photochemically, resulting in the release of carbon dioxide (CO2) to the atmosphere. The magnitude of this carbon loss can be affected by land management (e.g. drainage). Furthermore, DOC affects autotrophic and heterotrophic processes in aquatic ecosystems, and, when chlorinated during water treatment, can lead to the release of harmful trihalomethanes. Numerous methods have been used to characterise DOC. The most accessible of these use absorbance and fluorescence properties to make inferences about chemical composition, whilst high-performance size exclusion chromatography can be used to determine apparent molecular weight. XAD fractionation has been extensively used to separate out hydrophilic and hydrophobic components. Thermochemolysis or pyrolysis Gas Chromatography - Mass Spectrometry (GC-MS) give information on molecular properties of DOC, and 13C NMR spectroscopy can provide an insight into the degree of aromaticity. Proton Transfer Reaction - Mass Spectrometry (PTR-MS) is a sensitive, soft ionisation method suitable for qualitative and quantitative analysis of volatile and semi-volatile organic vapours. So far, PTR-MS has been used in various environmental applications such as real-time monitoring of volatile organic compounds (VOCs) emitted from natural and anthropogenic sources, chemical composition measurements of aerosols etc. However, as the method is not compatible with water, it has not been used for analysis of organic traces present in natural water samples. The aim of this work was to develop a method based on thermal desorption PTR-MS to analyse water samples in order to characterise chemical composition of dissolved organic carbon. We developed a clean low-pressure evaporation/sublimation system to remove water from samples and thermal desorption system to introduce

  2. Rapid screening of basic colorants in processed vegetables through mass spectrometry using an interchangeable thermal desorption electrospray ionization source.

    Science.gov (United States)

    Chao, Yu-Ying; Chen, Yen-Ling; Lin, Hong-Yi; Huang, Yeou-Lih

    2018-06-20

    Thermal desorption electrospray ionization/mass spectrometry (TD-ESI-MS) employing a quickly interchangeable ionization source is a relatively new ambient ionization mass spectrometric technique that has had, to date, only a limited number of applications related to food safety control. With reallocation of resources, this direct-analysis technique has had wider use in food analysis when operated in dual-working mode (pretreatment-free qualitative screening and conventional quantitative confirmation) after switching to an ambient ionization source from a traditional atmospheric pressure ionization source. Herein, we describe the benefits and challenges associated with the use of a TD-ESI source to detect adulterants in processed vegetables (PVs), as a proof-of-concept for the detection of basic colorants. While TD-ESI can offer direct qualitative screening analyses for PVs with detection capabilities lower than those provided with liquid chromatography/UV detection within 30 s, the use of TD-ESI for semi-quantification is applicable only for homogeneous food matrices. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Direct Surface Analysis of Fungal Species by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, Nancy B.(BATTELLE (PACIFIC NW LAB)); Wahl, Jon H.(BATTELLE (PACIFIC NW LAB)); Kingsley, Mark T.(BATTELLE (PACIFIC NW LAB)); Wahl, Karen L.(BATTELLE (PACIFIC NW LAB))

    2001-12-01

    Intact spores and/or hyphae of Aspergillus niger, Rhizopus oryzae, Trichoderma reesei and Phanerochaete chrysosporium are analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). This study investigates various methods of sample preparation and matrices to determine optimum collection and analysis criteria for fungal analysis by MALDI-MS. Fungi are applied to the MALDI sample target as untreated, sonicated, acid/heat treated, or blotted directly from the fungal culture with double-stick tape. Ferulic acid or sinapinic acid matrix solution is layered over the dried samples and analyzed by MALDI-MS. Statistical analysis of the data show that simply using double stick tape to collect and transfer to a MALDI sample plate typically worked as well as the other preparation methods, but requires the least sample handling.

  4. Thermopiles - a new thermal desorption technology for recycling highly organic contaminated soils down to natural levels

    International Nuclear Information System (INIS)

    Haemers, J.; Cardot, J.; Falcinelli, U.; Zwaan, H.

    2005-01-01

    The Thermopile R technology, developed by Deep Green, provides an implementation system allowing to treat hydrocarbon and PAH contaminated materials down to natural levels or down to levels where they are treatable with a traditional thermal desorption unit, in a controlled batch system. The materials are indirectly heated while a substantial part of the energy is reused to heat the pile of soil. The system differs from most of the indirect thermal desorption systems by its very high energetic efficiency as well as its ability to be set -up remotely. The system does not face preferential path problems, since the heating medium is only conduction, which is very indifferent with regard to soil type (clay, sand, silt, etc.). That property is critical to an in-depth clean-up with a batch system. Other systems, based on heat, are mostly sending heat vectors (gases, hot air, steam, etc.) through the soil, which implies preferential paths, which are the main cause for not completely cleaning the soil with most batch technologies (down to natural levels). The soil to treat is placed in a pile or in a modular container in which perforated steel pipes are installed along a hexagonal pattern. During treatment those pipes are heated by hot gases (about 600 deg. C) coming from the afterburner. Consequently the soil reaches the contaminant's desorption temperature. The desorbed pollutants are then drawn by convection and diffusion into the heating pipes via the perforations. Once in the pipes the desorbed gases are mixed with the heating gases. They are sucked by the ID fan and sent to the afterburner. The hydrocarbons in gaseous phase are then oxidized in the afterburner. In this manner, they provide a part of the energy needed to heat the soil itself. The pilot unit is also equipped with a purge that allows the evacuation of a part of the gases circulating in the system; Different additional gas treatments can be applied as required by the type of contaminants and the

  5. Kinetic compensation effect in the thermal desorption of a binary gas mixture

    Science.gov (United States)

    Zuniga-Hansen, Nayeli; Silbert, Leonardo E.; Calbi, M. Mercedes

    The kinetic compensation effect, observed in many different areas of science, is the systematic change in the magnitudes of the Arrhenius parameters Ea, the energy of activation and ν, the preexponential factor, as a response to external perturbing parameters. Its existence continues to be debated as it has not been explicitly demonstrated and its physical origins remain poorly understood. As part of a systematic study of different factors that alter the energy of activation during thermal desorption, we have performed numerical studies of the effects of adsorbate-adsorbate interactions on the Arrhenius parameters, as well as the effects of changes in surface morphology. Our results have consistently shown that there is a partial compensation effect between Ea and lnν and a tendency towards isokinetic equilibrium when the system transitions from an interacting to a non-interacting regime. In the present work we study the effects of the presence of two different chemical species. With our systematic study we expect to provide a deeper insight into the microscopic events that originate compensation effects, not only in our system, but also in other fields where these effects have been reported.

  6. GoAmazon 2014/15 Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, JN [Univ. of California, Irvine, CA (United States)

    2016-04-01

    The Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) deployment to the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility T3 site in Manacapuru, Brazil, was motivated by two main scientific objectives of the Green Ocean Amazon (GoAmazon) 2014/15 field campaign. 1) Study the interactions between anthropogenic and biogenic emissions by determining important molecular species in ambient nanoparticles. To address this, TDCIMS data will be combined with coincident measurements such as gas-phase sulfuric acid to determine the contribution of sulfuric acid condensation to nucleation and growth. We can then compare that result to TDCIMS-derived nanoparticle composition to determine the fraction of growth that can be attributed to the uptake of organic compounds. The molecular composition of sampled particles will also be used to attribute specific chemical species and mechanisms to growth, such as the condensation of low-volatility species or the oligomerization of α-dicarbonyl compounds. 2) Determine the source of new ambient nanoparticles in the Amazon. The hypothesis prior to measurements was that potassium salts formed from the evaporation of primary particles emitted by fungal spores can provide a unique and important pathway for new particle production in the Amazon basin. To explore this hypothesis, the TDCIMS recorded the mass spectra of sampled ambient particles using a protonated water cluster Chemical Ionization Mass Spectrometer (CIMS). Laboratory tests performed using potassium salts show that the TDCIMS can detect potassium with high sensitivity with this technique.

  7. Thermal desorption of hydrogen from Mg2Ni hydrogen storage materials.

    Science.gov (United States)

    Hur, Tae Hong; Han, Jeong Seb; Kim, Jin Ho; Kim, Byung Kwan

    2011-07-01

    In order to investigate the influence of HCS on the hydrogen occupation site of Mg2Ni alloy, the thermal desorption technique has been applied to Mg2Ni hydride made by hydriding combustion synthesis (HCS). Mg2Ni was made under low temperature in a short time by the HCS compared to conventional melting process. At various initial hydride wt% from 0.91 to 3.52, the sample was heated to 623 K at a rate of 1.0 K/min. The starting temperature of the evolution of hydrogen goes higher as the initial hydride wt% increases. Only one peak is shown in the case of the small initial hydride wt%. But two peaks appeared with increasing initial hydride wt%. The activation energies obtained by the first and second peaks are 113.0 and 99.5 kJ/mol respectively. The two site occupation model by Darriet et al. was proved. The influence of HCS on the hydrogen occupation site of Mg2Ni alloy is nonexistent.

  8. Effects of alloying elements on thermal desorption of helium in Ni alloys

    International Nuclear Information System (INIS)

    Xu, Q.; Cao, X.Z.; Sato, K.; Yoshiie, T.

    2012-01-01

    It is well known that the minor elements Si and Sn can suppress the formation of voids in Ni alloys. In the present study, to investigate the effects of Si and Sn on the retention of helium in Ni alloys, Ni, Ni–Si, and Ni–Sn alloys were irradiated by 5 keV He ions at 723 K. Thermal desorption spectroscopy (TDS) was performed at up to 1520 K, and microstructural observations were carried out to identify the helium trapping sites during the TDS analysis. Two peaks, at 1350 and 1457 K, appeared in the TDS spectrum of Ni. On the basis of the microstructural observations, the former peak was attributed to the release of trapped helium from small cavities and the latter to its release from large cavities. Small-cavity helium trapping sites were also found in the Ni–Si and Ni–Sn alloys, but no large cavities were observed in these alloys. In addition, it was found that the oversized element Sn could trap He atoms in the Ni–Sn alloy.

  9. Effects of alloying elements on thermal desorption of helium in Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q., E-mail: xu@rri.kyoto-u.ac.jp [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Cao, X.Z.; Sato, K.; Yoshiie, T. [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan)

    2012-12-15

    It is well known that the minor elements Si and Sn can suppress the formation of voids in Ni alloys. In the present study, to investigate the effects of Si and Sn on the retention of helium in Ni alloys, Ni, Ni-Si, and Ni-Sn alloys were irradiated by 5 keV He ions at 723 K. Thermal desorption spectroscopy (TDS) was performed at up to 1520 K, and microstructural observations were carried out to identify the helium trapping sites during the TDS analysis. Two peaks, at 1350 and 1457 K, appeared in the TDS spectrum of Ni. On the basis of the microstructural observations, the former peak was attributed to the release of trapped helium from small cavities and the latter to its release from large cavities. Small-cavity helium trapping sites were also found in the Ni-Si and Ni-Sn alloys, but no large cavities were observed in these alloys. In addition, it was found that the oversized element Sn could trap He atoms in the Ni-Sn alloy.

  10. Effects of alloying elements on thermal desorption of helium in Ni alloys

    Science.gov (United States)

    Xu, Q.; Cao, X. Z.; Sato, K.; Yoshiie, T.

    2012-12-01

    It is well known that the minor elements Si and Sn can suppress the formation of voids in Ni alloys. In the present study, to investigate the effects of Si and Sn on the retention of helium in Ni alloys, Ni, Ni-Si, and Ni-Sn alloys were irradiated by 5 keV He ions at 723 K. Thermal desorption spectroscopy (TDS) was performed at up to 1520 K, and microstructural observations were carried out to identify the helium trapping sites during the TDS analysis. Two peaks, at 1350 and 1457 K, appeared in the TDS spectrum of Ni. On the basis of the microstructural observations, the former peak was attributed to the release of trapped helium from small cavities and the latter to its release from large cavities. Small-cavity helium trapping sites were also found in the Ni-Si and Ni-Sn alloys, but no large cavities were observed in these alloys. In addition, it was found that the oversized element Sn could trap He atoms in the Ni-Sn alloy.

  11. Helium implanted RAFM steels studied by positron beam Doppler Broadening and Thermal Desorption Spectroscopy

    International Nuclear Information System (INIS)

    Carvalho, I; Schut, H; Fedorov, A; Luzginova, N; Desgardin, P; Sietsma, J

    2013-01-01

    Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion and Generation IV fission reactors. To mimic neutron irradiation conditions, Eurofer97 samples were implanted with helium ions at energies of 500 keV and 2 MeV and doses of 5x10 15 -10 16 He /cm 2 , creating atomic displacements in the range 0.07–0.08 dpa. The implantation induced defects were characterized by positron beam Doppler Broadening (DB) and Thermal Desorption Spectroscopy (TDS). The DB data could be fitted with one or two layers of material, depending on the He implantation energy. The S and W values obtained for the implanted regions suggest the presence of not only vacancy clusters but also positron traps of the type present in a sub-surface region found on the reference sample. The traps found in the implanted layers are expected to be He n V m clusters. For the 2 MeV, 10 16 He/cm 2 implanted sample, three temperature regions can be observed in the TDS data. Peaks below 450 K can be ascribed to He released from vacancies in the neighbourhood of the surface, the phase transition is found at 1180 K and the peak at 1350 K is likely caused by the migration of bubbles.

  12. Defects in TiN and HfN studied by helium thermal desorption spectrometry

    International Nuclear Information System (INIS)

    Hoondert, W.H.B.; Thijsse, B.J.; Beuckel, A. van den

    1994-01-01

    Point defects in sub-stoichiometric TiN 1-x and HfN 1-x were investigated by helium thermal desorption spectrometry (300-1800K) following He + ion implantation at energies up to 3000eV. It was found that the low energy spectra are dominated by helium dissociating from the structural vacancies on the nitrogen sublattice; the activation energy for dissociation is 2.2eV for TiN. Above a few hundred electron volts the ions begin to produce several other types of defects, from which helium dissociates with activation energies in the range 2.6-4.0eV. The identity of these defects is discussed. The results for the two nitrides were similar in many respects. The most significant difference observed is that in TiN low energy He + ions generate damage on the N sublattice of a type that is not observed for HfN. Activation energies for HfN are found to be consistently 0.7eV lower than for TiN. ((orig.))

  13. MERCURY QUANTIFICATION IN SOILS USING THERMAL DESORPTION AND ATOMIC ABSORPTION SPECTROMETRY: PROPOSAL FOR AN ALTERNATIVE METHOD OF ANALYSIS

    Directory of Open Access Journals (Sweden)

    Liliane Catone Soares

    2015-08-01

    Full Text Available Despite the considerable environmental importance of mercury (Hg, given its high toxicity and ability to contaminate large areas via atmospheric deposition, little is known about its activity in soils, especially tropical soils, in comparison with other heavy metals. This lack of information about Hg arises because analytical methods for determination of Hg are more laborious and expensive compared to methods for other heavy metals. The situation is even more precarious regarding speciation of Hg in soils since sequential extraction methods are also inefficient for this metal. The aim of this paper is to present a technique of thermal desorption associated with atomic absorption spectrometry, TDAAS, as an efficient tool for quantitative determination of Hg in soils. The method consists of the release of Hg by heating, followed by its quantification by atomic absorption spectrometry. It was developed by constructing calibration curves in different soil samples based on increasing volumes of standard Hg2+ solutions. Performance, accuracy, precision, and quantification and detection limit parameters were evaluated. No matrix interference was detected. Certified reference samples and comparison with a Direct Mercury Analyzer, DMA (another highly recognized technique, were used in validation of the method, which proved to be accurate and precise.

  14. Removal of Persistent Organic Pollutants from a Solid Matrix by Thermal Desorption Technology Using Conventional and Microwave Heating

    Czech Academy of Sciences Publication Activity Database

    Mašín, P.; Hendrych, J.; Kroužek, J.; Kubal, M.; Kochánková, L.; Sobek, Jiří

    2013-01-01

    Roč. 22, č. 7A (2013), s. 2017-2021 ISSN 1018-4619. [International Conference on Environmental Management , Engineering, Planning and Economics (CEMEPE 2011) & SECOTOX Conference /3./. Skiathos Island, 19.06.2011-24.06.2011] Grant - others:GA MŽP(CZ) SP/2f3/133/08 Institutional support: RVO:67985858 Keywords : thermal desorption * microwave heating * remediation * persistent pollutants * pilot scale Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.527, year: 2013

  15. Ink dating using thermal desorption and gas chromatography / mass spectrometry: comparison of results obtained in two laboratories

    OpenAIRE

    Koenig, A.; Bügler, J.; Kirsch, D.; Köhler, F.; Weyermann, C.

    2015-01-01

    Recent ink dating methods focused mainly on changes in solvent amounts occurring over time. A promising method was developed at the Landeskriminalamt of Munich using thermal desorption (TD) followed by gas chromatography / mass spectrometry (GC/MS) analysis. Sequential extractions of the phenoxyethanol present in ballpoint pen ink entries were carried out at two different temperatures. This method is applied in forensic practice and is currently implemented in several laboratories participati...

  16. Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

    2015-12-01

    Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

  17. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Metabolic Profiling Directly from the Petri Dish Using Nanospray Desorption Electrospray Ionization Imaging Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Watrous, Jeramie D.; Roach, Patrick J.; Heath, Brandi S.; Alexandrov, Theodore; Laskin, Julia; Dorrestein, Pieter C.

    2013-11-05

    Understanding molecular interaction pathways in complex biological systems constitutes a treasure trove of knowledge that might facilitate the specific, chemical manipulation of the countless microbiological systems that occur throughout our world. However, there is a lack of methodologies that allow the direct investigation of chemical gradients and interactions in living biological systems, in real time. Here, we report the use of nanospray desorption electrospray ionization (nanoDESI) imaging mass spectrometry for in vivo metabolic profiling of living bacterial colonies directly from the Petri dish with absolutely no sample preparation needed. Using this technique, we investigated single colonies of Shewanella oneidensis MR-1, Bacillus subtilis 3610, and Streptomyces coelicolor A3(2) as well as a mixed biofilm of S. oneidensis MR-1 and B. subtilis 3610. Data from B. subtilis 3610 and S. coelicolor A3(2) provided a means of validation for the method while data from S. oneidensis MR-1 and the mixed biofilm showed a wide range of compounds that this bacterium uses for the dissimilatory reduction of extracellular metal oxides, including riboflavin, iron-bound heme and heme biosynthetic intermediates, and the siderophore putrebactin.

  19. Desorption of surface positrons: A source of free positronium at thermal velocities

    International Nuclear Information System (INIS)

    Mills, A.P. Jr.; Pfeiffer, L.

    1979-01-01

    A direct measurement is reported of the velocity of positronium (Ps) ejected into a vacuum when 0- to 100-eV positrons (e + ) strike a negatively biased Cu(111) surface. At 30 0 C, about half the e + form Ps with normal energy component E-bar=3.4(3) eV. At 790 0 C, most of the remaining e + form Ps but with E-bar=0.14(1) eV, and a non-Maxwellian thermal distribution. We infer that surface-bound e + are thermally desorbed to form the extra Ps. These low Ps velocities suggest exciting possibilities for experiments on free Ps

  20. Analysis of the technique Thermal Desorption Spectroscopy (TDS) and its Application for the Characterization of Metal -Hydrogen Systems

    International Nuclear Information System (INIS)

    Castro, F.J.

    2000-01-01

    We present the theoretical and experimental developments made to study the desorption of hydrogen from metallic samples by Thermal Desorption Spectroscopy (TDS). With this technique gas desorption is stimulated by the programmed heating of the sample. To perform the study we set up a newly designed equipment and develop theoretical models of the kinetic processes involved. The equipment and the models are used to analyze the desorption process in a real system. We begin by analyzing the models developed to interpret the results of the experiments. These models consider simultaneously bulk diffusion and surface reaction processes in metal-hydrogen systems with one or two thermodynamic phases. We present numerical results, computer simulations and analytical approximations of the original models. Based on these results we analyze the main features of the spectra for the different relevant kinetic processes, and determine the changes induced in them when material parameters (activation energies, geometry) or experimental parameters (heating speed, initial concentration) are modified.We present the original equipment, designed and constructed during this work to perform the TDS experiments. We describe its main characteristics, its components, its range of operation and its sensibility. We also offer an analysis of the background spectrum. We use the Pd-H system to test the equipment and the models. The samples chosen, powders, granules, foils and wires, were previously characterized to analyze their composition, their morphology and their characteristic size. We show the results of Scanning Electron Microscopy (SEM) observation, X ray diffraction (XRD) and Auger Electron Spectroscopy (AES) analysis.We then present and analyze in depth the experimental desorption spectra of the palladium powder. Based on the analysis we determine the rate limiting step for desorption and the characteristic activation energies. When the system is on the b phase (hydride) the rate

  1. Microwave-Enhanced Thermal Desorption of Polyhalogenated Biphenyls from Contaminated Soil

    Czech Academy of Sciences Publication Activity Database

    Kaštánek, P.; Kaštánek, František; Hájek, Milan

    2010-01-01

    Roč. 136, č. 3 (2010), s. 295-300 ISSN 0733-9372 Institutional research plan: CEZ:AV0Z40720504 Keywords : microwave * experiments * desorption Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.117, year: 2010

  2. Biological functioning of PAH-polluted and thermal desorption-treated soils assessed by fauna and microbial bioindicators.

    Science.gov (United States)

    Cébron, Aurélie; Cortet, Jérôme; Criquet, Stéven; Biaz, Asmaa; Calvert, Virgile; Caupert, Cécile; Pernin, Céline; Leyval, Corinne

    2011-11-01

    A large number of soil bioindicators were used to assess biological diversity and activity in soil polluted with polycyclic aromatic hydrocarbons (PAHs) and the same soil after thermal desorption (TD) treatment. Abundance and biodiversity of bacteria, fungi, protozoa, nematodes and microarthropods, as well as functional parameters such as enzymatic activities and soil respiration, were assessed during a two year period of in situ monitoring. We investigated the influence of vegetation (spontaneous vegetation and Medicago sativa) and TD treatment on biological functioning. Multivariate analysis was performed to analyze the whole data set. A principal response curve (PRC) technique was used to evaluate the different treatments (various vegetation and contaminated vs. TD soil) contrasted with control (bare) soil over time. Our results indicated the value of using a number of complementary bioindicators, describing both diversity and functions, to assess the influence of vegetation on soil and discriminate polluted from thermal desorption (TD)-treated soil. Plants had an influence on the abundance and activity of all organisms examined in our study, favoring the whole trophic chain development. However, although TD-treated soil had a high abundance and diversity of microorganisms and fauna, enzymatic activities were weak because of the strong physical and chemical modifications of this soil. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  3. Application of Thermal Desorption Unit (TDU) to treat low-toxicity mineral oil base cuttings in Barinas District, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Rendon, Ruben [Petroleos de Venezuela, Caracas (Venezuela); Luzardo, Janeth; Alcoba, Alcides [M-I SWACO, Houston, TX (United States)

    2008-07-01

    The potential environmental impact of oil-based drill cuttings is generating increased scrutiny in the oil and gas industry. If left untreated, oil-based cuttings not only increase the risk of environmental liabilities, but also affect revenue, as drilling generates wastes that in most cases require special treatment before disposal. Consequently, the oil industry is looking for technologies to help minimize environmental liabilities. Accordingly, the Barinas District of PDVSA has started a pilot trial to treat oil-based drilling cuttings by applying thermal desorption technology. The main objective of this technology is recovering trapped hydrocarbons, while minimizing wastes and preparing solids to be disposed of through a mobile treatment plant. This novel technology has been used worldwide to treat organic pollutants in soil. Thermal desorption is a technology based on the application of heat in soils polluted with organic compounds. With this technology, target temperatures vary according to the type and concentration of detected pollutants along with its characterization, in such a way that compounds are disposed of by volatilization. As part of the integral waste management development along with the pilot trial for hydrocarbon-contaminated solid waste treatment, trials on soils were undertaken by applying process-generated ashes in equally-sized bins, with different mixtures (ashes, ashes organic material, ashes-organic material-sand, ashes-land). The resulting process offers an immediate soil remediation and final disposal solution for toxic and dangerous waste. (author)

  4. Distribution and removal of organochlorine pesticides in waste clay bricks from an abandoned manufacturing plant using low-temperature thermal desorption technology.

    Science.gov (United States)

    Cong, Xin; Li, Fasheng; Kelly, Ryan M; Xue, Nandong

    2018-04-01

    The distribution of pollutants in waste clay bricks from an organochlorine pesticide-contaminated site was investigated, and removal of the pollutants using a thermal desorption technology was studied. The results showed that the contents of HCHs in both the surface and the inner layer of the bricks were slightly higher than those of DDTs. The total pore volume of the bricks was 37.7 to 41.6% with an increase from external to internal surfaces. The removal efficiency by thermal treatment was within 62 to 83% for HCHs and DDTs in bricks when the temperature was raised from 200 to 250 °C after 1 h. HCHs were more easily removed than DDTs with a higher temperature. Either intraparticle or surface diffusion controls the desorption processes of pollutants in bricks. It was feasible to use the polluted bricks after removal of the pollutants by low-temperature thermal desorption technology.

  5. Effects of thermal desorption on the composition of two coking plant soils: Impact on solvent extractable organic compounds and metal bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Biache, Coralie [G2R UMR 7566, Nancy Universite, CNRS, Boulevard des Aiguillettes B.P. 239, F-54506 Vandoeuvre-les-Nancy (France); LIMOS UMR 7137, Nancy Universite, CNRS, Boulevard des Aiguillettes B.P. 239, F-54506 Vandoeuvre-les-Nancy (France)], E-mail: coralie.biache@g2r.uhp-nancy.fr; Mansuy-Huault, Laurence; Faure, Pierre [G2R UMR 7566, Nancy Universite, CNRS, Boulevard des Aiguillettes B.P. 239, F-54506 Vandoeuvre-les-Nancy (France); Munier-Lamy, Colette; Leyval, Corinne [LIMOS UMR 7137, Nancy Universite, CNRS, Boulevard des Aiguillettes B.P. 239, F-54506 Vandoeuvre-les-Nancy (France)

    2008-12-15

    To evaluate the efficiency and the influence of thermal desorption on the soil organic compartment, contaminated soils from coking plant sites (NM and H) were compared to their counterparts treated with thermodesorption. The extractable organic matter, and the metal content and distribution with soil compartments were studied. In both thermodesorbed soils, PAH (polycyclic aromatic hydrocarbon) degradation exceeded 90%. However, the thermal desorption led not only to a volatilization of the organic compounds but also to the condensation of extractable organic matter. The treatments only affected the Fe and Zn distribution within the more stable fractions, whereas the organic compound degradation did not affect their mobility and availability. - Thermal desorption does not induce a metal mobilization but condensation seems to occur during the treatment.

  6. Thermal desorption of deuterium from Be, and Be with helium bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, A.V.; Van Veen, A.; Busker, G.J. [Delft Univ. of Technology (Netherlands). Interfaculty Reactor Inst.

    1998-01-01

    Deuterium desorption measurements carried out on a single-crystalline beryllium sample are presented. Deuterium ions were implanted at room temperature at the energy of 0.7 and 1.2 keV up to doses ranging from 10{sup 19} to 3.6 x 10{sup 21} m{sup -2}. In order to eliminate the influence of the beryllium-oxide surface layer, before the implantation the surface of the sample was cleaned by argon sputtering. After the implantation the sample was annealed up to 1200 K at a constant rate of 10 K/s. Deuterium released from the sample was monitored by a calibrated quadrupole mass-spectrometer. The desorption spectra revealed two different contributions. One is a well defined and very narrow peak centered around 450 K. This peak is observed only at high implantation doses > 7.8 x 10{sup 20} m{sup -2}, which is close to the deuterium saturation limit of 0.3 D/Be and is related to deuterium release from blisters or interconnected bubbles. The activation energy of 1.1 eV and the threshold implantation dose are consistent with the values reported in literature. The second contribution in the release spectra is found in the temperature range from 600 to 900 K and is present throughout the whole range of the implantation doses. The activation energies corresponding to this release lie in the range between 1.8 and 2.5 eV and are ascribed to the release from deuterium-vacancy type of defects. In a number of experiments the deuterium implantation was preceded by helium implantation followed by partial annealing to create helium bubbles. The resulting deuterium desorption spectra indicate that deuterium detrapping from helium bubbles is characterized by an activation energy of 2.7 eV. (author)

  7. Molecular Beam-Thermal Desorption Spectrometry (MB-TDS Monitoring of Hydrogen Desorbed from Storage Fuel Cell Anodes

    Directory of Open Access Journals (Sweden)

    Jorge H. F. Ribeiro

    2012-02-01

    Full Text Available Different types of experimental studies are performed using the hydrogen storage alloy (HSA MlNi3.6Co0.85Al0.3Mn0.3 (Ml: La-rich mischmetal, chemically surface treated, as the anode active material for application in a proton exchange membrane fuel cell (PEMFC. The recently developed molecular beam—thermal desorption spectrometry (MB-TDS technique is here reported for detecting the electrochemical hydrogen uptake and release by the treated HSA. The MB-TDS allows an accurate determination of the hydrogen mass absorbed into the hydrogen storage alloy (HSA, and has significant advantages in comparison with the conventional TDS method. Experimental data has revealed that the membrane electrode assembly (MEA using such chemically treated alloy presents an enhanced surface capability for hydrogen adsorption.

  8. Molecular Beam-Thermal Desorption Spectrometry (MB-TDS) Monitoring of Hydrogen Desorbed from Storage Fuel Cell Anodes.

    Science.gov (United States)

    Lobo, Rui F M; Santos, Diogo M F; Sequeira, Cesar A C; Ribeiro, Jorge H F

    2012-02-06

    Different types of experimental studies are performed using the hydrogen storage alloy (HSA) MlNi 3.6 Co 0.85 Al 0.3 Mn 0.3 (Ml: La-rich mischmetal), chemically surface treated, as the anode active material for application in a proton exchange membrane fuel cell (PEMFC). The recently developed molecular beam-thermal desorption spectrometry (MB-TDS) technique is here reported for detecting the electrochemical hydrogen uptake and release by the treated HSA. The MB-TDS allows an accurate determination of the hydrogen mass absorbed into the hydrogen storage alloy (HSA), and has significant advantages in comparison with the conventional TDS method. Experimental data has revealed that the membrane electrode assembly (MEA) using such chemically treated alloy presents an enhanced surface capability for hydrogen adsorption.

  9. Thermal desorption of toluene from Vanadium-containing catalysts coated onto various carriers

    Directory of Open Access Journals (Sweden)

    Z. Zheksenbaeva

    2012-12-01

    Full Text Available The method temperature-programmed desorption has been studied the state of toluene on the surface-modified vanadium catalysts on different carriers. Among the investigated carriers the most active in the reaction of partial oxidation of toluene is anatase structural titanium dioxide. For the partial oxidation of toluene on modified vanadium-containing catalysts deposited on TiO2 was tested. It was found that on the catalyst 20%V2O5-5%MoO3-2%Sb2O3/TiO2 at a temperature of 673K, volume rate of 15 thousand hours-1 oxidation of toluene is 80% c yield of benzoic acid with a selectivity of  70% of 87.5%.

  10. Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

    International Nuclear Information System (INIS)

    Venugopal, V.; Seijbel, L.J.; Thijsse, B.J.

    2005-01-01

    Thermal helium desorption spectrometry (THDS) has been used for the investigation of defects and thermal stability of thin Cu films (5-200 A ) deposited on a polycrystalline Mo substrate in ultrahigh vacuum. These films are metastable at room temperature. On heating, the films transform into islands, giving rise to a relatively broad peak in the helium desorption spectra. The temperature of this island formation is dependent on film thickness, being 417 K for 10 A and 1100 K for a 200 A film. The activation energy for island formation was found to be 0.3±0.1 eV for 75 A film. Grain boundaries have a strong effect on island formation. The defect concentration in the as-deposited films is ∼5x10 -4 , for films thicker than 50 A and more for thinner films. Helium release from monovacancies was identified in the case of a 200 A film. Helium release was also seen during sublimation of the Cu film (∼1350 K). Overlayer experiments were used to identify helium trapped close to the film surface. An increase of the substrate temperature during deposition resulted in a film that had already formed islands. Argon-ion assistance (250 eV) during film deposition with an ion/atom ratio of ∼0.1 resulted in a significant enhancement of helium trapping in the films. The argon concentration in the films was found to be 10 -3 . The temperature of island formation was increased due to argon-ion assistance. The helium and argon desorption spectra are found to be similar, which is due to most of the helium becoming trapped in the defects created by the argon beam. The role of the Mo surface in affecting the defects at the film-substrate interface is investigated. The effect of variation of helium fluence and helium implantation energy is also considered. The present THDS results of Cu/poly-Mo are compared to those of Cu/Mo(100) and Cu/Mo(100) reported earlier

  11. Retention model for sorptive extraction-thermal desorption of aqueous samples : application to the automated analysis of pesticides and polyaromatic hydrocarbons in water samples

    NARCIS (Netherlands)

    Baltussen, H.A.; David, F.; Sandra, P.J.F.; Janssen, J.G.M.; Cramers, C.A.M.G.

    1998-01-01

    In this report, an automated method for sorptive enrichment of aqueous samples is presented. It is based on sorption of the analytes of interest into a packed bed containing 100% polydimethylsiloxane (PDMS) particles followed by thermal desorption for complete transfer of the enriched solutes onto

  12. Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sangwon [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    Matrix-assisted laser desorption/ionization(MALDI) mass spectrometry(MS) has been widely used for analysis of biological molecules, especially macromolecules such as proteins. However, MALDI MS has a problem in small molecule (less than 1 kDa) analysis because of the signal saturation by organic matrixes in the low mass region. In imaging MS (IMS), inhomogeneous surface formation due to the co-crystallization process by organic MALDI matrixes limits the spatial resolution of the mass spectral image. Therefore, to make laser desorption/ionization (LDI) MS more suitable for mass spectral profiling and imaging of small molecules directly from raw biological tissues, LDI MS protocols with various alternative assisting materials were developed and applied to many biological systems of interest. Colloidal graphite was used as a matrix for IMS of small molecules for the first time and methodologies for analyses of small metabolites in rat brain tissues, fruits, and plant tissues were developed. With rat brain tissues, the signal enhancement for cerebroside species by colloidal graphite was observed and images of cerebrosides were successfully generated by IMS. In addition, separation of isobaric lipid ions was performed by imaging tandem MS. Directly from Arabidopsis flowers, flavonoids were successfully profiled and heterogeneous distribution of flavonoids in petals was observed for the first time by graphite-assisted LDI(GALDI) IMS.

  13. Direct isotope determination of isotopically labelled lipids by field desorption mass spectrometry

    International Nuclear Information System (INIS)

    Lehmann, W.D.; Kessler, M.

    1982-01-01

    Lipids labelled with deuterium or carbon-14 have been investigated by field desorption mass spectrometry for determination of their degree of labelling. This application is demonstrated for free fatty acids, cholesterol, cholesteryl esters, triglycerides, and L-α-phosphatidylcholines. Comparison of the molecular ion groups of the non-labelled and of the labelled compounds enables a fast and reliable determination of the degree of labelling. For multiply labelled compounds the label distribution is also obtained from the molecular ion group. In addition, for cholesteryl esters and for phosphatidylcholines structurally significant fragment ions provide information about the position of the label. Several hundred nanograms of the compound are typically required for a single analysis with a relative standard error of 0.5-2% in the value calculated for atom% hydrogen-2 or for the specific carbon-14 activity. (orig.) [de

  14. Demonstration Testing of a Thermal Desorption Unit to Receive and Treat Waste with Unlimited Concentration of PCBs - 13437

    Energy Technology Data Exchange (ETDEWEB)

    Orton, Timothy L. [EnergySolutions, 423 West 300 South, Salt Lake City, UT 84101 (United States); Palmer, Carl R. [TD.X Associates LP, 148 South Dowlen Road, PMB 700, Beaumont, TX 77707 (United States)

    2013-07-01

    For the last nine years, EnergySolutions and TD*X Associates LP have teamed up to provide the most comprehensive organic removal treatment process in the radioactive waste industry. The high performance thermal desorption unit (HP-TDU) located at the EnergySolutions Clive facility in Utah has successfully processed over 1,850 tons of organically contaminated radioactive mixed waste. Products from the HP-TDU system include a radioactively contaminated dry solid material that can be disposed in the on-site landfill and an organic condensate with high thermal energy content that is generally below background radiation and capable of free-release to a non-radioactive incinerator. Over the years, Permits and approvals have been obtained through the state of Utah, United States Environmental Protection Agency (USEPA) Region 8, and USEPA headquarters that enable the treatment of several waste categories including volatile and semi-volatile organic compounds, combustion-coded (CMBST) compounds, volatile metals, and polychlorinated biphenyls (PCBs). The unit has recently successfully completed Demonstration Testing for PCB concentrations up to 660,000 ppm (parts per million). Solid processed material from this Demonstration Testing was less than two ppm PCBs in three separate treatment runs; reprocessing or additional treatment was not needed to meet this limit. Through post-demonstration permitting, the system is unlimited in scope as approval has been given to receive and solidify up to pure PCBs down to this processing limit concentration to complete treatment of mixed waste. (authors)

  15. Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

    Science.gov (United States)

    Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

    2016-12-01

    Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

  16. Direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry improves appropriateness of antibiotic treatment of bacteremia.

    Directory of Open Access Journals (Sweden)

    Anne L M Vlek

    Full Text Available Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS allows the identification of microorganisms directly from positive blood culture broths. Use of the MALDI-TOF MS for rapid identification of microorganisms from blood culture broths can reduce the turnaround time to identification and may lead to earlier appropriate treatment of bacteremia. During February and April 2010, direct MALDI-TOF MS was routinely performed on all positive blood cultures. During December 2009 and March 2010 no direct MALDI-TOF MS was used. Information on antibiotic therapy was collected from the hospital and intensive care units' information systems from all positive blood cultures during the study period. In total, 253 episodes of bacteremia were included of which 89 during the intervention period and 164 during the control period. Direct performance of MALDI-TOF MS on positive blood culture broths reduced the time till species identification by 28.8-h and was associated with an 11.3% increase in the proportion of patients receiving appropriate antibiotic treatment 24 hours after blood culture positivity (64.0% in the control period versus 75.3% in the intervention period (p0.01. Routine implementation of this technique increased the proportion of patients on adequate antimicrobial treatment within 24 hours.

  17. Direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry improves appropriateness of antibiotic treatment of bacteremia.

    Science.gov (United States)

    Vlek, Anne L M; Bonten, Marc J M; Boel, C H Edwin

    2012-01-01

    Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows the identification of microorganisms directly from positive blood culture broths. Use of the MALDI-TOF MS for rapid identification of microorganisms from blood culture broths can reduce the turnaround time to identification and may lead to earlier appropriate treatment of bacteremia. During February and April 2010, direct MALDI-TOF MS was routinely performed on all positive blood cultures. During December 2009 and March 2010 no direct MALDI-TOF MS was used. Information on antibiotic therapy was collected from the hospital and intensive care units' information systems from all positive blood cultures during the study period. In total, 253 episodes of bacteremia were included of which 89 during the intervention period and 164 during the control period. Direct performance of MALDI-TOF MS on positive blood culture broths reduced the time till species identification by 28.8-h and was associated with an 11.3% increase in the proportion of patients receiving appropriate antibiotic treatment 24 hours after blood culture positivity (64.0% in the control period versus 75.3% in the intervention period (p0.01)). Routine implementation of this technique increased the proportion of patients on adequate antimicrobial treatment within 24 hours.

  18. Re-emission and thermal desorption of deuterium from plasma sprayed tungsten coatings for application in ASDEX-upgrade

    International Nuclear Information System (INIS)

    Garcia-Rosales, C.; Franzen, P.; Plank, H.; Roth, J.; Gauthier, E.

    1996-01-01

    The trapping and release of deuterium implanted with an energy of 100 eV in wrought and in plasma sprayed tungsten of different manufacture and structure has been investigated by means of re-emission as well as thermal and isothermal desorption spectroscopy. The experimental data for wrought tungsten are compared with model calculations with the PIDAT code in order to estimate the parameters governing diffusion, surface recombination and trapping in tungsten. The amount of retained deuterium in tungsten is of the same order of magnitude as in graphite for the implantation parameters used in this work. The mobile hydrogen concentration in tungsten during the implantation is of the same order of magnitude than the trapped one, being released after the termination of the implantation. The fraction of deuterium trapped to defects increases strongly with the porosity of the samples. The temperature needed for the release of the trapped deuterium (∝600 K) are considerably lower than for graphite, due to the smaller trapping energy (≤1.5 eV). (orig.)

  19. Hydrogen isotope inventory in the graphite divertor tiles of ASDEX Upgrade as measured by thermal desorption spectroscopy

    International Nuclear Information System (INIS)

    Franzen, P.; Behrisch, R.; Garcia-Rosales, C.; Schleussner, D.; Roesler, D.; Becker, J.; Knapp, W.; Edelmann, C.

    1997-01-01

    The hydrogen and deuterium inventories of the ASDEX Upgrade divertor tiles were measured after the experimental period from December 1994 to July 1995 by thermal desorption spectroscopy (TDS) of samples cut out of the divertor tiles. The samples were heated by electron bombardment up to 2100 K; the released gases were measured by means of a calibrated quadrupole mass spectrometer. The measured hydrogen or deuterium inventories are of the order of 10 23 m -2 . They are larger for samples of the inner divertor than of the outer divertor by a factor of about 2. The largest inventory was found at the separatrix position of the inner divertor. Most of the released hydrogen (H) can be attributed to water adsorbed in the near surface region during the air exposure prior to the TDS measurements. The total inventories measured by TDS exceed the inventories in the near surface region (< 25 μm) measured by ion beam analysis methods by a factor of up to 10. Hence, the total hydrogen retention is governed by the diffusion out of the near surface region deep into the material. The hydrogen and deuterium inventories decreased with increasing surface temperature. (author). 64 refs, 12 figs, 2 tabs

  20. Rapid Quantification of N-Methyl-2-pyrrolidone in Polymer Matrices by Thermal Desorption-GC/MS.

    Science.gov (United States)

    Kim, Young-Min; Kim, Jae Woo; Moon, Hye Mi; Lee, Min-Jin; Hosaka, Akihiko; Watanabe, Atsushi; Teramae, Norio; Park, Young-Kwon; Myung, Seung-Woon

    2017-01-01

    Analysis of a residual solvent in polymeric materials has become an important issue due to the increased regulations and standards for its use. N-Methyl-2-pyrrolidone (NMP) is a solvent widely used in many industries and restricted as one of the chemicals under EU REACH regulations due to its potential harmful effects. In this study, thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) is applied for the quantitative analysis of NMP with the use of a polymer-coated sample cup. By using the polymer-coated sample cup, the vaporization of NMP was prevented during waiting time before TD-GC/MS analysis. The calibration curve for the TD method showed good linearity (correlation coefficient, r 2 = 0.9998) and precision values (below 5.3% RSD). NMP recovery rates in different polymer matrices (PS, PMMA and PVC) were in the range of 98.8 to 106.6% with RSD values below 5.0%. The quantification result (600 mg NMP/kg PVC) for the blind NMP carrying sample in a PVC matrix by TD-GC/MS was higher than that (532 mg NMP/kg PVC) by solvent extraction-GC/MS method.

  1. Evaluation of laser diode thermal desorption-tandem mass spectrometry (LDTD-MS-MS) in forensic toxicology.

    Science.gov (United States)

    Bynum, Nichole D; Moore, Katherine N; Grabenauer, Megan

    2014-10-01

    Many forensic laboratories experience backlogs due to increased drug-related cases. Laser diode thermal desorption (LDTD) has demonstrated its applicability in other scientific areas by providing data comparable with instrumentation, such as liquid chromatography-tandem mass spectrometry, in less time. LDTD-MS-MS was used to validate 48 compounds in drug-free human urine and blood for screening or quantitative analysis. Carryover, interference, limit of detection, limit of quantitation, matrix effect, linearity, precision and accuracy and stability were evaluated. Quantitative analysis indicated that LDTD-MS-MS produced precise and accurate results with the average overall within-run precision in urine and blood represented by a %CV forensic toxicology but before it can be successfully implemented that there are some challenges that must be addressed. Although the advantages of the LDTD system include minimal maintenance and rapid analysis (∼10 s per sample) which makes it ideal for high-throughput forensic laboratories, a major disadvantage is its inability or difficulty analyzing isomers and isobars due to the lack of chromatography without the use of high-resolution MS; therefore, it would be best implemented as a screening technique. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Comparison of two common adsorption materials for thermal desorption gas chromatography - mass spectrometry of biogenic volatile organic compounds.

    Science.gov (United States)

    Marcillo, Andrea; Jakimovska, Viktorija; Widdig, Anja; Birkemeyer, Claudia

    2017-09-08

    Volatile organic compounds (VOCs) are commonly collected from gaseous samples by adsorption to materials such as the porous polymer Tenax TA. Adsorbed compounds are subsequently released from these materials by thermal desorption (TD) and separated then by gas chromatography (GC) with flame ionization (FID) or mass spectrometry (MS) detection. Tenax TA is known to be particularly suitable for non-polar to semipolar volatiles, however, many volatiles from environmental and biological samples possess a rather polar character. Therefore, we tested if the polymer XAD-2, which so far is widely used to adsorb organic compounds from aqueous and organic solvents, could provide a broader coverage for (semi)polar VOCs during gas-phase sampling. Mixtures of volatile compounds covering a wide range of volatility (bp. 20-256°C) and different chemical classes were introduced by liquid spiking into sorbent tubes with one of the two porous polymers, Tenax TA or XAD-2, and analyzed by TD/GC-MS. At first, an internal standard mixture composed of 17 authentic standards was used to optimize desorption temperature with respect to sorbent degradation and loading time for calibration. Secondly, we tested the detectability of a complex standard mixture composed of 57 volatiles, most of them common constituents of the body odor of mammals. Moreover, the performance of XAD-2 compared with Tenax TA was assessed as limit of quantitation and linearity for the internal standard mixture and 33 compounds from the complex standard mixture. Volatiles were analyzed in a range between 0.01-∼250ng/tube depending on the compound and material. Lower limits of quantitation were between 0.01 and 3 ng±0.9). Interestingly, we found different kinetics for compound adsorption with XAD-2, and a partially better sensitivity in comparison with Tenax TA. For these analytes, XAD-2 might be recommended as an alternative of Tenax TA for TD/GC-MS analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. High-throughput trace analysis of explosives in water by laser diode thermal desorption/atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Badjagbo, Koffi; Sauvé, Sébastien

    2012-07-03

    Harmful explosives can accumulate in natural waters in the long term during their testing, usage, storage, and dumping and can pose a health risk to humans and the environment. For the first time, attachment of small anions to neutral molecules in laser diode thermal desorption/atmospheric pressure chemical ionization was systematically investigated for the direct determination of trace nitroaromatics, nitrate esters, and nitramine explosives in water. Using ammonium chloride as an additive improved the instrument response for all the explosives tested and promoted the formation of several characteristic adduct ions. The method performs well achieving good linearity over at least 2 orders of magnitude, with coefficients of determination greater than 0.995. The resulting limits of detection are in the range of 0.009-0.092 μg/L. River water samples were successfully analyzed by the proposed method with accuracy in the range of 96-98% and a response time of 15 s, without any further pretreatment or chromatographic separation.

  4. Mercury recovery from mercury-containing wastes using a vacuum thermal desorption system.

    Science.gov (United States)

    Lee, Woo Rim; Eom, Yujin; Lee, Tai Gyu

    2017-02-01

    Mercury (Hg)-containing waste from various industrial facilities is commonly treated by incineration or stabilization/solidification and retained in a landfill at a managed site. However, when highly concentrated Hg waste is treated using these methods, Hg is released into the atmosphere and soil environment. To eliminate these risks, Hg recovery technology using thermal treatment has been developed and commercialized to recover Hg from Hg-containing waste for safe disposal. Therefore, we developed Hg recovery equipment to treat Hg-containing waste under a vacuum of 6.67kPa (abs) at 400°C and recover the Hg. In addition, the dust generated from the waste was separated by controlling the temperature of the dust filtration unit to 230°C. Additionally, water and Hg vapors were condensed in a condensation unit. The Hg removal rate after waste treatment was 96.75%, and the Hg recovery rate as elemental Hg was 75.23%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Reduction of polycyclic aromatic hydrocarbons (PAHs) from petroleum-contaminated soil using thermal desorption technology

    International Nuclear Information System (INIS)

    Silkebakken, D.M.; Davis, H.A.; Ghosh, S.B.; Beardsley, G.P.

    1995-01-01

    The remediation of petroleum-contaminated soil typically requires the selection of a treatment option that addresses the removal of both volatile and semi-volatile organic compounds. Volatile organic compounds (VOCs), primarily BTEX (benzene, toluene, ethylbenzene, and xylenes) compounds, can be readily removed from the soil by a variety of well-established technologies. The semivolatile organic compounds, especially the polycyclic aromatic hydrocarbons (PAHS) that are characteristic of petroleum-contaminated soil, are not as amenable to conventional treatment. Low temperature thermal volatilization (LTTV) can be a viable treatment technology depending on the initial contaminant concentrations present and applicable cleanup objectives that must be attained. A-two-phase treatability study was conducted at 14 former underground storage tank (UST) sites to evaluate the applicability and effectiveness of LTTV for remediation of approximately 31,000 tons of PAH-contaminated soil. The PAHs of primary concern included benzo(a)anthracene, chrysene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(g,h,i)perylene, dibenz(a,h) anthracene, and indeno(1,2,3-cd)pyrene. During Phase 1, LTTV operational parameters were varied by trial-and-error and changes in soil treatment effectiveness were monitored. Phase B of the treatability study incorporated the appropriate treatment regime established during Phase 1 to efficiently remediate the remaining contaminated soil

  6. Residual thermal desorption studies of Ga adatoms on trenched Si(5 5 12) surface

    International Nuclear Information System (INIS)

    Kumar, Praveen; Kumar, Mahesh; Shivaprasad, S.M.

    2013-01-01

    We present here the thermal stability studies of the room temperature adsorbed Ga/Si(5 5 12) interfaces in the monolayer coverage regime, using AES and LEED as in-situ UHV characterization probes. Ga grows in Stranski–Krastanov growth mode at RT on the 2 × 1 reconstructed Si(5 5 12) surface where islands form on top of 2 ML of flat pseudomorphic Ga, yielding a (1 × 1) LEED pattern for coverages of 1.2 ML and above. When this RT adsorbed Ga/Si(5 5 12) interface is annealed at different temperatures, initially the strained Ga adlayers relax by agglomerating into 3D islands on top of a single Ga monolayer with an activation energy of 0.19 eV in the temperature range of 200–300 °C. The remnant Ga monolayer with a sharp (1 × 1) LEED pattern desorbs at temperature >400 °C, yielding the (1 1 2)–6 × 1 and 2 × (3 3 7) sub-monolayer superstructural. Finally at 720 °C Ga completely desorbs from the surface and leaves the clean 2 × 1 reconstructed Si(5 5 12) surface. The studies demonstrate the richness of the atomically trenched high index Si(5 5 12) surface, in obtaining several anisotropic features that can be used as templates to grow self-assembled nanostructures.

  7. Residual thermal desorption studies of Ga adatoms on trenched Si(5 5 12) surface

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen [Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India); ISOM, Universidad Politecnia de Madrid, 28040 (Spain); Kumar, Mahesh [Physics and Energy Harvesting Group, National Physical Laboratory, New Delhi 110012 (India); Shivaprasad, S.M., E-mail: smsprasad@jncasr.ac.in [Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

    2013-10-01

    We present here the thermal stability studies of the room temperature adsorbed Ga/Si(5 5 12) interfaces in the monolayer coverage regime, using AES and LEED as in-situ UHV characterization probes. Ga grows in Stranski–Krastanov growth mode at RT on the 2 × 1 reconstructed Si(5 5 12) surface where islands form on top of 2 ML of flat pseudomorphic Ga, yielding a (1 × 1) LEED pattern for coverages of 1.2 ML and above. When this RT adsorbed Ga/Si(5 5 12) interface is annealed at different temperatures, initially the strained Ga adlayers relax by agglomerating into 3D islands on top of a single Ga monolayer with an activation energy of 0.19 eV in the temperature range of 200–300 °C. The remnant Ga monolayer with a sharp (1 × 1) LEED pattern desorbs at temperature >400 °C, yielding the (1 1 2)–6 × 1 and 2 × (3 3 7) sub-monolayer superstructural. Finally at 720 °C Ga completely desorbs from the surface and leaves the clean 2 × 1 reconstructed Si(5 5 12) surface. The studies demonstrate the richness of the atomically trenched high index Si(5 5 12) surface, in obtaining several anisotropic features that can be used as templates to grow self-assembled nanostructures.

  8. Direct imaging of plant metabolites in leaves and petals by Desorption Electrospray Ionization mass spectrometry

    DEFF Research Database (Denmark)

    Li, Bin; Hansen, Steen Honore'; Janfelt, Christian

    2013-01-01

    and demonstrated on leaves and petals of Hypericum perforatum. The direct imaging approaches are in contrast to previous DESI imaging studies where indirect analysis via imprints were used in order to overcome the morphological barrier presented by the layer of cuticular waxes covering the surface of a leaf...... of very long chain fatty acids (VLCFAs), a significant class of metabolites located in the cuticle layer in leaves and petals, as well as other plant metabolites. In the case of the petals of H. perforatum, all common metabolites could be imaged directly using the ternary solvent, whereas in the case...... of leaves from the same plant, only some of the metabolites were accessible, even with the ternary solvent system. For these samples, the leaves could be imaged with direct DESI after chloroform had been used to remove most of the cuticle, thus exposing lower layers in the leaf structure. A number...

  9. Control of Strobilurin Fungicides in Wheat Using Direct Analysis in Real Time Accurate Time-of-Flight and Desorption Electrospray Ionization Linear Ion Trap Mass Spectrometry

    NARCIS (Netherlands)

    Schurek, J.; Vaclavik, L.; Hooijerink, H.; Lacina, O.; Poustka, J.; Sharman, M.; Caldow, M.; Nielen, M.W.F.; Hajslova, J.

    2008-01-01

    Ambient mass spectrometry has been used for the analysis of strobilurin residues in wheat. The use of this novel, challenging technique, employing a direct analysis in a real time (DART) ion-source coupled with a time-of-flight mass spectrometer (TOF MS) and a desorption electrospray ionization

  10. Direct detection of neutral metal atoms in electron-stimulated desorption: Al from CH3O/Al(111) - velocity distribution and absolute yield

    International Nuclear Information System (INIS)

    Whitten, J.E.; Young, C.E.; Pellin, M.J.; Gruen, D.M.; Jones, P.L.

    1994-01-01

    Electron-stimulated desorption of neutral aluminum from the system CH 3 O/Al(111) has been directly monitored via quasiresonant photoionization with 193 nm excimer laser light and confirmed by two-step resonant ionization, utilizing the Al 3d 2 D manifold. Velocity distribution measurements for the neutral Al peak at ∼ 800 m/s for 1 keV incident electron energy. An absolute yield of 3.2 x 10 -6 Al atoms/electron was determined by comparison with sputtering measurements in the same apparatus. This is the first observation of electron-stimulated metal desorption from adsorbate-covered metallic surfaces

  11. Adsorption, desorption, and film formation of quinacridone and its thermal cracking product indigo on clean and carbon-covered silicon dioxide surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Scherwitzl, Boris; Lassnig, Roman; Truger, Magdalena; Resel, Roland; Leising, Günther; Winkler, Adolf, E-mail: a.winkler@tugraz.at [Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

    2016-09-07

    The evaporation of quinacridone from a stainless steel Knudsen cell leads to the partial decomposition of this molecule in the cell, due to its comparably high sublimation temperature. At least one additional type of molecules, namely indigo, could be detected in the effusion flux. Thermal desorption spectroscopy and atomic force microscopy have been used to study the co-deposition of these molecules on sputter-cleaned and carbon-covered silicon dioxide surfaces. Desorption of indigo appears at temperatures of about 400 K, while quinacridone desorbs at around 510 K. For quinacridone, a desorption energy of 2.1 eV and a frequency factor for desorption of 1 × 10{sup 19} s{sup −1} were calculated, which in this magnitude is typical for large organic molecules. A fraction of the adsorbed quinacridone molecules (∼5%) decomposes during heating, nearly independent of the adsorbed amount, resulting in a surface composed of small carbon islands. The sticking coefficients of indigo and quinacridone were found to be close to unity on a carbon covered SiO{sub 2} surface but significantly smaller on a sputter-cleaned substrate. The reason for the latter can be attributed to insufficient energy dissipation for unfavorably oriented impinging molecules. However, due to adsorption via a hot-precursor state, the sticking probability is increased on the surface covered with carbon islands, which act as accommodation centers.

  12. Analysis of airborne pesticides from different chemical classes adsorbed on Radiello® Tenax® passive tubes by thermal-desorption-GC/MS.

    Science.gov (United States)

    Raeppel, Caroline; Fabritius, Marie; Nief, Marie; Appenzeller, Brice M R; Briand, Olivier; Tuduri, Ludovic; Millet, Maurice

    2015-02-01

    An analytical methodology using automatic thermal desorption (ATD) and GC/MS was developed for the determination of 28 pesticides of different chemical classes (dichlobenil, carbofuran, trifluralin, clopyralid, carbaryl, flazasulfuron, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, cyprodinil, bromoxynil, fluroxypyr, oxadiazon, myclobutanil, buprofezin, picloram, trinexapac-p-ethyl, ioxynil, diflufenican, tebuconazole, bifenthrin, isoxaben, alphacypermethrin, fenoxaprop and tau-fluvalinate) commonly used in nonagricultural areas in atmospheric samples. This methodology was developed to evaluate the indoor and outdoor atmospheric contamination by nonagricultural pesticides. Pesticides were sampled passive sampling tubes containing Tenax® adsorbent. Since most of these pesticides are polar (clopyralid, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, bromoxynil, fluroxypyr, picloram, trinexapac-p-ethyl and ioxynil), a derivatisation step is required. For this purpose, a silylation step using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MtBSTFA) was added before thermal desorption. This agent was chosen since it delivers very specific ions on electronic impact (m/z = M-57). This method was established with special consideration for optimal thermal desorption conditions (desorption temperature, desorb flow and duration; trap heating duration and flow; outlet split), linear ranges, limits of quantification and detection which varied from 0.005 to 10 ng and from 0.001 to 2.5 ng, respectively, for an uncertainty varied from 8 to 30 %. The method was applied in situ to the analysis of passive tubes exposed during herbicide application to an industrial site in east of France.

  13. A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-11-01

    Full Text Available We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes (Zhang et al., 2014. Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF, where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS, TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level

  14. Microorganisms direct identification from blood culture by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Ferreira, L; Sánchez-Juanes, F; Porras-Guerra, I; García-García, M I; García-Sánchez, J E; González-Buitrago, J M; Muñoz-Bellido, J L

    2011-04-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows a fast and reliable bacterial identification from culture plates. Direct analysis of clinical samples may increase its usefulness in samples in which a fast identification of microorganisms can guide empirical treatment, such as blood cultures (BC). Three hundred and thirty BC, reported as positive by the automated BC incubation device, were processed by conventional methods for BC processing, and by a fast method based on direct MALDI-TOF MS. Three hundred and eighteen of them yield growth on culture plates, and 12 were false positive. The MALDI-TOF MS-based method reported that no peaks were found, or the absence of a reliable identification profile, in all these false positive BC. No mixed cultures were found. Among these 318 BC, we isolated 61 Gram-negatives (GN), 239 Gram-positives (GP) and 18 fungi. Microorganism identifications in GN were coincident with conventional identification, at the species level, in 83.3% of BC and, at the genus level, in 96.6%. In GP, identifications were coincident with conventional identification in 31.8% of BC at the species level, and in 64.8% at the genus level. Fungaemia was not reliably detected by MALDI-TOF. In 18 BC positive for Candida species (eight C. albicans, nine C. parapsilosis and one C. tropicalis), no microorganisms were identified at the species level, and only one (5.6%) was detected at the genus level. The results of the present study show that this fast, MALDI-TOF MS-based method allows bacterial identification directly from presumptively positive BC in a short time (<30 min), with a high accuracy, especially when GN bacteria are involved. © 2010 The Authors. Clinical Microbiology and Infection © 2010 European Society of Clinical Microbiology and Infectious Diseases.

  15. Some new features of Direct Analysis in Real Time mass spectrometry utilizing the desorption at an angle option.

    Science.gov (United States)

    Chernetsova, Elena S; Revelsky, Alexander I; Morlock, Gertrud E

    2011-08-30

    The present study is a first step towards the unexplored capabilities of Direct Analysis in Real Time (DART) mass spectrometry (MS) arising from the possibility of the desorption at an angle: scanning analysis of surfaces, including the coupling of thin-layer chromatography (TLC) with DART-MS, and a more sensitive analysis due to the preliminary concentration of analytes dissolved in large volumes of liquids on glass surfaces. In order to select the most favorable conditions for DART-MS analysis, proper positioning of samples is important. Therefore, a simple and cheap technique for the visualization of the impact region of the DART gas stream onto a substrate was developed. A filter paper or TLC plate, previously loaded with the analyte, was immersed in a derivatization solution. On this substrate, owing to the impact of the hot DART gas, reaction of the analyte to a colored product occurred. An improved capability of detection of DART-MS for the analysis of liquids was demonstrated by applying large volumes of model solutions of coumaphos into small glass vessels and drying these solutions prior to DART-MS analysis under ambient conditions. This allowed the introduction of, by up to more than two orders of magnitude, increased quantities of analyte compared with the conventional DART-MS analysis of liquids. Through this improved detectability, the capabilities of DART-MS in trace analysis could be strengthened. Copyright © 2011 John Wiley & Sons, Ltd.

  16. Analysis of wastewater samples by direct combination of thin-film microextraction and desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Strittmatter, Nicole; Düring, Rolf-Alexander; Takáts, Zoltán

    2012-09-07

    An analysis method for aqueous samples by the direct combination of C18/SCX mixed mode thin-film microextraction (TFME) and desorption electrospray ionization mass spectrometry (DESI-MS) was developed. Both techniques make analytical workflow simpler and faster, hence the combination of the two techniques enables considerably shorter analysis time compared to the traditional liquid chromatography mass spectrometry (LC-MS) approach. The method was characterized using carbamazepine and triclosan as typical examples for pharmaceuticals and personal care product (PPCP) components which draw increasing attention as wastewater-derived environmental contaminants. Both model compounds were successfully detected in real wastewater samples and their concentrations determined using external calibration with isotope labeled standards. Effects of temperature, agitation, sample volume, and exposure time were investigated in the case of spiked aqueous samples. Results were compared to those of parallel HPLC-MS determinations and good agreement was found through a three orders of magnitude wide concentration range. Serious matrix effects were observed in treated wastewater, but lower limits of detection were still found to be in the low ng L(-1) range. Using an Orbitrap mass spectrometer, the technique was found to be ideal for screening purposes and led to the detection of various different PPCP components in wastewater treatment plant effluents, including beta-blockers, nonsteroidal anti-inflammatory drugs, and UV filters.

  17. Thermal transformation of bioactive caffeic acid on fumed silica seen by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry and quantum chemical methods.

    Science.gov (United States)

    Kulik, Tetiana V; Lipkovska, Natalia O; Barvinchenko, Valentyna M; Palyanytsya, Borys B; Kazakova, Olga A; Dudik, Olesia O; Menyhárd, Alfréd; László, Krisztina

    2016-05-15

    Thermochemical studies of hydroxycinnamic acid derivatives and their surface complexes are important for the pharmaceutical industry, medicine and for the development of technologies of heterogeneous biomass pyrolysis. In this study, structural and thermal transformations of caffeic acid complexes on silica surfaces were studied by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry (TPD MS) and quantum chemical methods. Two types of caffeic acid surface complexes are found to form through phenolic or carboxyl groups. The kinetic parameters of the chemical reactions of caffeic acid on silica surface are calculated. The mechanisms of thermal transformations of the caffeic chemisorbed surface complexes are proposed. Thermal decomposition of caffeic acid complex chemisorbed through grafted ester group proceeds via three parallel reactions, producing ketene, vinyl and acetylene derivatives of 1,2-dihydroxybenzene. Immobilization of phenolic acids on the silica surface improves greatly their thermal stability. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Ion mobility spectrometry–mass spectrometry studies of ion processes in air at atmospheric pressure and their application to thermal desorption of 2,4,6-trinitrotoluene

    International Nuclear Information System (INIS)

    Sabo, Martin; Malásková, Michaela; Matejčík, Štefan

    2014-01-01

    In this study we have investigated the negative reactant ion formation in a negative corona discharge (CD) using the corona discharge ion mobility spectrometry orthogonal acceleration time-of-flight (CD-IMS-oaTOF) technique. The reactant ions were formed in the CD operating in the reverse gas flow mode at an elevated temperature of 363.5 K in synthetic and ambient air. Under these conditions mainly O 2 − and their clusters were formed. We have also studied the influence of CCl 4 admixture to air (dopant gas) on the composition of the reactant ions, which resulted in the formation of Cl − and its clusters with a reduced ion mobility of 3.05 cm 2  V −1  s −1 as a major reactant ion peak. Additional IMS peaks with reduced ion mobilities of 2.49, 2.25 and 2.03 cm 2  V −1  s −1 were detected, and Cl −  · (NO 2 ) and Cl −  · (NO) n (n = 2, 3) anions were identified. The negative reactant ions were used to detect 2,4,6 trinitrotoluene (TNT) using the thermal desorption (TD) technique using a CD-IMS instrument. Using TD sampling and a negative CD ion source doped by CCl 4 we have achieved a limit of detection of 350 pg for direct surface analysis of TNT. (paper)

  19. Ultra-fast photo-patterning of hydroxamic acid layers adsorbed on TiAlN: The challenge of modeling thermally induced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Hemgesberg, Maximilian [Fachbereich Chemie, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 54, 67663 Kaiserslautern (Germany); Schuetz, Simon [Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 45, 67663 Kaiserslautern (Germany); Heidelberger Druckmaschinen AG, Kurfuerstenanlage 54-60, 66120 Heidelberg (Germany); Mueller, Christine [Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 45, 67663 Kaiserslautern (Germany); Schloerholz, Matthias; Latzel, Harald [Heidelberger Druckmaschinen AG, Kurfuerstenanlage 54-60, 66120 Heidelberg (Germany); Sun, Yu [Fachbereich Chemie, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 54, 67663 Kaiserslautern (Germany); Ziegler, Christiane [Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 45, 67663 Kaiserslautern (Germany); Thiel, Werner R., E-mail: thiel@chemie.uni-kl.de [Fachbereich Chemie, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 54, 67663 Kaiserslautern (Germany)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Different hydroxamic acids are suitable for the hydrophobization of TiAlN surfaces used in photo-patterning applications. Black-Right-Pointing-Pointer The binding strength of the surfactant on the surface is dependent on the hydrogen and {pi}-bonding interactions within the organic layer. Black-Right-Pointing-Pointer Thermal desorption of selected HA species results in a 20% energy reduction compared to alkyl phosphates. - Abstract: Long-chain n-alkyl terminated hydroxamic acids (HA) are used for the modification of titanium aluminum nitride (TiAlN) surfaces. HA coatings improve the hydrophobicity of this wear resistant and industrially relevant ceramic. Therefore, HAs with different structural properties are evaluated with respect to their wear resistance and their thermal desorption properties. In order to find new coatings for rewritable offset printing plates, the changes in the surface polarity, composition, and morphology are analyzed by contact angle measurements, X-ray photoemission spectroscopy (XPS), and scanning force microscopy (SFM), respectively. The results are referenced to the strongly bonding molecule n-dodecyl phosphonate (PO11M), which has been used for surface hydrophobization before but proved difficult to remove due to the high laser outputs required for thermal desorption. It is found that for certain HAs, an equally good hydrophobization compared to PO11M can be achieved. Contact angles obtained for different hydroxamic acid coatings can be correlated to their modes of adsorption. Only for selected HA species, resistance to mechanical wear is sufficient for further investigations. Photo-patterning of these hydroxamic acid layers is achieved using a high energy IR laser beam at different energy inputs. Fitting of the obtained data and further evaluation using finite element analysis (FEM) calculations reveal significantly reduced energy consumption of about 20% for the removal of a specific hydroxamic

  20. Performance evaluation of a thermal desorption/gas chromatographic/mass spectrometric method for the characterization of waste tank headspace samples

    International Nuclear Information System (INIS)

    Ma, C.Y.; Skeen, J.T.; Dindal, A.B.; Bayne, C.K.; Jenkins, R.A.

    1997-01-01

    A thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) method was validated for the determination of volatile organic compounds collected on carbonaceous triple sorbent traps and applied to characterize samples of headspace gases collected from underground nuclear waste storage tanks at the U.S. Department of Energy's Hanford site, in Richland, WA. Method validation used vapor-phase standards generated from 25 target analytes, including alkanes, alkyl alcohols, alkyl ketones, alkylated aromatics, and alkyl nitriles. The target analytes represent a group of compounds identified in one of the most problematic tanks. TD/GC/MS was carried out with modified injectors. Performance was characterized based on desorption efficiency, reproducibility, stability, and linearity of the calibration, method detection limits, preanalytical holding time, and quality control limits for surrogate standard recoveries. Desorption efficiencies were all greater than 82%, and the majority of the analytes (23 out of 25) had reproducibility values less than 24% near the method detection levels. The method was applied to the analysis of a total of 305 samples collected from the headspaces of 48 underground waste storge tanks. Quality control procedures were implemented to monitor sampling and TD/GC/MS method. 33 refs., 2 figs., 4 tabs

  1. Use of thermal desorption gas chromatography-olfactometry/mass spectrometry for the comparison of identified and unidentified odor active compounds emitted from building products containing linseed oil

    DEFF Research Database (Denmark)

    Clausen, P. A.; Knudsen, Henrik Nellemose; Larsen, K.

    2008-01-01

    The emission of odor active volatile organic compounds (VOCs) from a floor oil based on linseed oil, the linseed oil itself and a low-odor linseed oil was investigated by thermal desorption gas chromatography combined with olfactometry and mass spectrometry (TD-GC-O/MS). The oils were applied...... to filters and conditioned in the micro emission cell, FLEC, for 1-3 days at ambient temperature, an air exchange rate of 26.9 h-1 and a 30% relative humidity. These conditions resulted in dynamic headspace concentrations and composition of the odor active VOCs that may be similar to real indoor setting...

  2. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Direct Bacterial Identification from Positive Blood Culture Pellets ▿

    OpenAIRE

    Prod'hom, Guy; Bizzini, Alain; Durussel, Christian; Bille, Jacques; Greub, Gilbert

    2010-01-01

    An ammonium chloride erythrocyte-lysing procedure was used to prepare a bacterial pellet from positive blood cultures for direct matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry analysis. Identification was obtained for 78.7% of the pellets tested. Moreover, 99% of the MALDI-TOF identifications were congruent at the species level when considering valid scores. This fast and accurate method is promising.

  3. Matrix-assisted laser desorption ionization-time of flight mass spectrometry for direct bacterial identification from positive blood culture pellets.

    Science.gov (United States)

    Prod'hom, Guy; Bizzini, Alain; Durussel, Christian; Bille, Jacques; Greub, Gilbert

    2010-04-01

    An ammonium chloride erythrocyte-lysing procedure was used to prepare a bacterial pellet from positive blood cultures for direct matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry analysis. Identification was obtained for 78.7% of the pellets tested. Moreover, 99% of the MALDI-TOF identifications were congruent at the species level when considering valid scores. This fast and accurate method is promising.

  4. The role of surface charging during the coadsorption of mercaptohexanol to DNA layers on gold: direct observation of desorption and layer reorientation.

    Science.gov (United States)

    Arinaga, K; Rant, U; Tornow, M; Fujita, S; Abstreiter, G; Yokoyama, N

    2006-06-20

    We study the coadsorption of mercaptohexanol onto preimmobilized oligonucleotide layers on gold. Monitoring the position of the DNA relative to the surface by optical means directly shows the mercaptohexanol-induced desorption of DNA and the reorientation of surface-tethered strands in situ and in real time. By simultaneously recording the electrochemical electrode potential, we are able to demonstrate that changes in the layer conformation are predominantly of electrostatic origin and can be reversed by applying external bias to the substrate.

  5. A Study on Thermal Desorption of Deuterium in D-loaded SS316LN for ITER Tritium Removal System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Myungchul; Kim, Heemoon; Ahn, Sangbok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jaeyong; Lee, Sanghwa; LanAhn, Nguyen Thi [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    Because Type B radwaste includes tritium on its inside, especially at vicinity of surface, tritium removal from the radwaste is a matter of concern in terms of the radwaste processes. Tritium behavior in materials is related with temperature. Considering a diffusion process, it is expected that tritium removal efficiency is enhanced with increasing baking temperature. However, there is a limitation about temperature due to facility capacity and economic aspect. Therefore, it is necessary to investigate the effect of temperature on the desorption behavior of Tritium in ITER materials. TDS analysis was performed in SS316LN loaded at 120, 240 and 350 °C. D2 concentration and the desorption peak temperature increased with increasing loading temperature. Using peak shift method with three ramp rates of 0.166, 0.332, and 0.5 °C/sec, trap activation energy of D in SS316LN loaded at 350 °C was 56 kJ/mol.

  6. A possible answer to the mysterious non-detection of hydroxylamine in space: the thermal desorption mechanism

    Science.gov (United States)

    Jonusas, Mindaugas; Krim, Lahouari

    2016-06-01

    The presence of NH2OH, one of the main precursors in the formation of amino-acids, on dust grain mantles, may be the most obvious elucidation for the creation of large pre-biotic molecules in the interstellar medium. However, while many laboratory experimental studies, to simulate the icy grain chemistry in space, found that NH2OH molecules may be easily formed in solid phase with high abundances and then they should desorb, through a temperature-induced desorption into the gas phase, with the same high abundances; all the spatial observations conclude that NH2OH is not detected in gas phase within any of the explored astronomical sources. Such inconsistencies between laboratory experiment simulations and spatial observations lead our investigations towards this experimental study to see if there is any chemical transformation of NH2OH, occurring in the solid phase before the desorption processes of NH2OH from the mantle of interstellar icy grains. Our experimental results show that the heating of NH2OH-H2O ices lead to a decomposition of NH2OH into HNO, NH3 and O2, even before reaching its desorption temperature. We show through this work that the NH2OH non-detection from previous examined astronomical sources could mainly due to its high reactivity in solid phase on the icy interstellar grains.

  7. Non-thermal desorption/ablation of molecular solids induced by ultra-short soft x-ray pulses

    Czech Academy of Sciences Publication Activity Database

    Chalupský, Jaromír; Juha, Libor; Hájková, Věra; Cihelka, Jaroslav; Vyšín, Luděk; Gautier, J.; Hajdu, J.; Hau-Riege, S.P.; Jurek, M.; Krzywinski, J.; London, R.A.; Papalazarou, E.; Pelka, J. B.; Rey, G.; Sebban, S.; Sobierajski, R.; Stojanovic, N.; Tiedtke, K.; Toleikis, S.; Tschentscher, T.; Valentin, C.; Wabnitz, H.; Zeitoun, P.

    2009-01-01

    Roč. 17, č. 1 (2009), s. 208-217 ISSN 1094-4087 R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Grant - others:EU FP6 NEST-Adventure(XE) 012843 Institutional research plan: CEZ:AV0Z10100523 Keywords : x-ray laser * high-order harmonics * free-electron laser * desorption * ablation * organic polymer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.278, year: 2009

  8. Development of a Microfluidic Open Interface with Flow Isolated Desorption Volume for the Direct Coupling of SPME Devices to Mass Spectrometry.

    Science.gov (United States)

    Tascon, Marcos; Alam, Md Nazmul; Gómez-Ríos, Germán Augusto; Pawliszyn, Janusz

    2018-02-20

    Technologies that efficiently integrate the sampling and sample preparation steps with direct introduction to mass spectrometry (MS), providing simple and sensitive analytical workflows as well as capabilities for automation, can generate a great impact in a vast variety of fields, such as in clinical, environmental, and food-science applications. In this study, a novel approach that facilitates direct coupling of Bio-SPME devices to MS using a microfluidic design is presented. This technology, named microfluidic open interface (MOI), which operates under the concept of flow-isolated desorption volume, consists of an open-to-ambient desorption chamber (V ≤ 7 μL) connected to an ionization source. Subsequently, compounds of interest are transported to the ionization source by means of the self-aspiration process intrinsic of these interfaces. Thus, any ionization technology that provides a reliable and constant suction, such as electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), or inductively coupled plasma ionization (ICP), can be hyphenated to MOI. Using this setup, the desorption chamber is used to release target compounds from the coating, while the isolation of the flow enables the ionization source to be continuously fed with solvent, all without the necessity of employment of additional valves. As a proof of concept, the design was applied to an ESI-MS/MS system for experimental validation. Furthermore, numerical simulations were undertaken to provide a detailed understanding of the fluid flow pattern inside the interface, then used to optimize the system for better efficiency. The analytical workflow of the developed Bio-SPME-MOI-MS setup consists of the direct immersion of SPME fibers into the matrix to extract/enrich analytes of interest within a short period of time, followed by a rinsing step with water to remove potentially adhering proteins, salts, and/or other interfering compounds. Next, the fiber is inserted into the

  9. Desorption, dissociation and orientation of oxygen admolecules on a reconstructed platinum(110)(1x2) surface studied by thermal desorption and near-edge X-ray-absorption fine-structure

    International Nuclear Information System (INIS)

    Ohno, Yuichi; Matsushima, Tatsuo; Tanaka, Shin-ichiro; Kamada, Masao

    1993-01-01

    The desorption, dissociation and orientation of oxygen admolecules on a reconstructed Pt(110)(1x2) were studied by means of TDS combined with isotope tracer, NEXAFS, and angle-resolved TDS. The admolecules below half a monolayer lie on the bottom of the trough, being oriented along it. The molecules adsorbed additionally are lying on declining terraces. The desorption flux of the former species shows a simple cosine distribution, suggesting that the molecule is not localized on the bottom in the desorption event. (author)

  10. Measurement of Passive Uptake Rates for Volatile Organic Compounds on Commercial Thermal Desorption Tubes and the Effect of Ozone on Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Maddalena, Randy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Parra, Amanda [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Russell, Marion [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lee, Wen-Yee [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-05-01

    Diffusive or passive sampling methods using commercially filled axial-sampling thermal desorption tubes are widely used for measuring volatile organic compounds (VOCs) in air. The passive sampling method provides a robust, cost effective way to measure air quality with time-averaged concentrations spanning up to a week or more. Sampling rates for VOCs can be calculated using tube geometry and Fick’s Law for ideal diffusion behavior or measured experimentally. There is evidence that uptake rates deviate from ideal and may not be constant over time. Therefore, experimentally measured sampling rates are preferred. In this project, a calibration chamber with a continuous stirred tank reactor design and constant VOC source was combined with active sampling to generate a controlled dynamic calibration environment for passive samplers. The chamber air was augmented with a continuous source of 45 VOCs ranging from pentane to diethyl phthalate representing a variety of chemical classes and physiochemical properties. Both passive and active samples were collected on commercially filled Tenax TA thermal desorption tubes over an 11-day period and used to calculate passive sampling rates. A second experiment was designed to determine the impact of ozone on passive sampling by using the calibration chamber to passively load five terpenes on a set of Tenax tubes and then exposing the tubes to different ozone environments with and without ozone scrubbers attached to the tube inlet. During the sampling rate experiment, the measured diffusive uptake was constant for up to seven days for most of the VOCs tested but deviated from linearity for some of the more volatile compounds between seven and eleven days. In the ozone experiment, both exposed and unexposed tubes showed a similar decline in terpene mass over time indicating back diffusion when uncapped tubes were transferred to a clean environment but there was no indication of significant loss by ozone reaction.

  11. Determination of 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene and related compounds in marine pore water by automated thermal desorption-gas chromatography/mass spectrometry using disposable optical fiber

    Science.gov (United States)

    Eganhouse, Robert P.; DiFilippo, Erica L

    2015-01-01

    A method is described for determination of ten DDT-related compounds in marine pore water based on equilibrium solid-phase microextraction (SPME) using commercial polydimethylsiloxane-coated optical fiber with analysis by automated thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Thermally cleaned fiber was directly exposed to sediments and allowed to reach equilibrium under static conditions at the in situ field temperature. Following removal, fibers were rinsed, dried and cut into appropriate lengths for storage in leak-tight containers at -20°C. Analysis by TD-GC/MS under full scan (FS) and selected ion monitoring (SIM) modes was then performed. Pore-water method detection limits in FS and SIM modes were estimated at 0.05-2.4ng/L and 0.7-16pg/L, respectively. Precision of the method, including contributions from fiber handling, was less than 10%. Analysis of independently prepared solutions containing eight DDT compounds yielded concentrations that were within 6.9±5.5% and 0.1±14% of the actual concentrations in FS and SIM modes, respectively. The use of optical fiber with automated analysis allows for studies at high temporal and/or spatial resolution as well as for monitoring programs over large spatial and/or long temporal scales with adequate sample replication. This greatly enhances the flexibility of the technique and improves the ability to meet quality control objectives at significantly lower cost.

  12. Modeling directional thermal radiance from a forest canopy

    International Nuclear Information System (INIS)

    McGuire, M.J.; Balick, L.K.; Smith, J.A.; Hutchison, B.A.

    1989-01-01

    Recent advances in remote sensing technology have increased interest in utilizing the thermal-infared region to gain additional information about surface features such as vegetation canopies. Studies have shown that sensor view angle, canopy structure, and percentage of canopy coverage can affect the response of a thermal sensor. These studies have been primarily of agricultural regions and there have been relatively few examples describing the thermal characteristics of forested regions. This paper describes an extension of an existing thermal vegetation canopy radiance model which has been modified to partially account for the geometrically rough structure of a forest canopy. Fourier series expansion of a canopy height profile is used to calculate improved view factors which partially account for the directional variations in canopy thermal radiance transfers. The original and updated radiance model predictions are compared with experimental data obtained over a deciduous (oak-hickory) forest site. The experimental observations are also used to document azimuthal and nadir directional radiance variations. Maximum angular variations in measured canopy temperatures were 4–6°C (azimuth) and 2.5°C (nadir). Maximum angular variations in simulated temperatures using the modified rough surface model was 4°C. The rough surface model appeared to be sensitive to large gaps in the canopy height profile, which influenced the resultant predicted temperature. (author)

  13. Bench- and pilot-scale demonstration of thermal desorption for removal of mercury from the Lower East Fork Poplar Creek floodplain soils

    International Nuclear Information System (INIS)

    Morris, M.I.; Sams, R.J.; Gillis, G.; Helsel, R.W.; Alperin, E.S.; Geisler, T.J.; Groen, A.; Root, D.

    1995-01-01

    Thermal desorption is an innovative technology that has seen significant growth in applications to organically contaminated soils and sludges for the remediation of hazardous, radioactive and mixed waste sites. This paper will present the results of a bench and pilot-scale demonstration of this technology for the removal of mercury from the Lower East Fork Poplar Creek floodplain soil. Results demonstrate that the mercury in this soil can be successfully removed to the target treatment levels of 10 milligrams per kilogram (mg/kg) and that all process residuals could be rendered RCRA-nonhazardous as defined by the Resource Conservation and Recovery Act. Sampling and analyses of the desorber off-gas before and after the air pollution control system demonstrated effective collection of mercury and organic constituents. Pilot-scale testing was also conducted to verify requirements for material handling of soil into and out of the process. This paper will also present a conceptual design and preliminary costs of a full-scale system, including feed preparation, thermal treatment, and residuals handling for the soil

  14. Determination of short chain chlorinated paraffins in water by stir bar sorptive extraction-thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Tölgyessy, P; Nagyová, S; Sládkovičová, M

    2017-04-21

    A simple, robust, sensitive and environment friendly method for the determination of short chain chlorinated paraffins (SCCPs) in water using stir bar sorptive extraction (SBSE) coupled to thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry (TD-GC-QqQ-MS/MS) was developed. SBSE was performed using 100mL of water sample, 20mL of methanol as a modifier, and a commercial sorptive stir bar (with 10mm×0.5mm PDMS layer) during extraction period of 16h. After extraction, the sorptive stir bar was thermally desorbed and online analysed by GC-MS/MS. Method performance was evaluated for MilliQ and surface water spiked samples. For both types of matrices, a linear dynamic range of 0.5-3.0μgL -1 with correlation coefficients >0.999 and relative standard deviations (RSDs) of the relative response factors (RRFs) <12% was established. The limits of quantification (LOQs) of 0.06 and 0.08μgL -1 , and the precision (repeatability) of 6.4 and 7.7% (RSDs) were achieved for MilliQ and surface water, respectively. The method also showed good robustness, recovery and accuracy. The obtained performance characteristics indicate that the method is suitable for screening and monitoring and compliance checking with environmental quality standards (EQS, set by the EU) for SCCPs in surface waters. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.

    Science.gov (United States)

    Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

    2014-08-08

    For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Simultaneous Screening of Major Flame Retardants and Plasticizers in Polymer Materials Using Pyrolyzer/Thermal Desorption Gas Chromatography Mass Spectrometry (Py/TD–GC–MS

    Directory of Open Access Journals (Sweden)

    Hiroyuki Yanagisawa

    2018-03-01

    Full Text Available This study was conducted with the aim of achieving the simultaneous screening of various additives in polymer materials by utilizing a solvent-free pyrolyzer/thermal desorption gas chromatography mass spectrometry (Py/TD-GC–MS method. As a first step to achieve this goal, simultaneous screening has been examined by selecting major substances representing plasticizers and flame retardants, such as short chain chlorinated paraffins (SCCPs, decabromodiphenyl ether (DecaBDE, hexabromocyclododecane (HBCDD, and di(2-ethylhexyl phthalate (DEHP. A quantitative MS analysis was performed to check for the peak areas and sensitivities. Since Py/TD-GC–MS is fraught with the risk of thermal degradation of the sample, temperatures during the analytical process were finely tuned for securing reliable results. The instrumental sensitivity was confirmed by the S/N ratio on each component. The detection limits of all components were less than 50 mg/kg, which are sufficiently lower than the regulatory criteria. With regard to reproducibility, a relative standard deviation (RSD of about 5% was confirmed by employing a spike recovery test on a polystyrene polymer solution containing mixed standard solution (ca. 1000 mg/kg. In conclusion, the results obtained in this study indicate that Py/TD-GC–MS is applicable for the screening of major flame retardants and plasticizers in real samples with sufficient reproducibility at regulatory levels.

  17. Direct detection of illicit drugs from biological fluids by desorption/ionization mass spectrometry with nanoporous silicon microparticles.

    Science.gov (United States)

    Guinan, T M; Kirkbride, P; Della Vedova, C B; Kershaw, S G; Kobus, H; Voelcker, N H

    2015-12-07

    Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is a high throughput analytical technique capable of detecting low molecular weight analytes, including illicit drugs, and with potential applications in forensic toxicology as well as athlete and workplace testing, particularly for biological fluids (oral fluids, urine and blood). However, successful detection of illicit drugs using SALDI-MS often requires extraction steps to reduce the inherent complexity of biological fluids. Here, we demonstrate an all-in-one extraction and analytical system consisting of hydrophobically functionalized porous silicon microparticles (pSi-MPs) for affinity SALDI-MS of prescription and illicit drugs. This novel approach allows for the analysis of drugs from multiple biological fluids without sample preparation protocols. The effect of pSi-MP size, pore diameter, pore depth and functionalization on analytical performance is investigated. pSi-MPs were optimized for the rapid and high sensitivity detection of methadone, cocaine and 3,4-methylenedioxymethamphetamine (MDMA). This optimized system allowed extraction and detection of methadone from spiked saliva and clinical urine samples. Furthermore, by detecting oxycodone in additional clinical saliva and plasma samples, we were able to demonstrate the versatility of the pSi-MP SALDI-MS technique.

  18. Directional radiative cooling thermal compensation for gravitational wave interferometer mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Justin Kamp, Carl [Department of Chemical Reaction Engineering, Chalmers University of Technology, SE-412 96 Goteborg (Sweden)], E-mail: carl.kamp@chalmers.se; Kawamura, Hinata [Yokoyama Junior High School, Sanda, Hachioji, Tokyo 193-0832 (Japan); Passaquieti, Roberto [Dipartimento di Fisica ' Enrico Fermi' and INFN Sezione di Pisa, Universita' di Pisa, Largo Bruno Pontecorvo, I-56127 Pisa (Italy); DeSalvo, Riccardo [LIGO Observatories, California Institute of Technology, Pasadena, CA 91125 (United States)

    2009-08-21

    The concept of utilizing directional radiative cooling to correct the problem of thermal lensing in the mirrors of the LIGO/VIRGO gravitational wave detectors has been shown and has prospects for future use. Two different designs utilizing this concept, referred to as the baffled and parabolic mirror solutions, have been proposed with different means of controlling the cooling power. The technique takes advantage of the power naturally radiated by the mirror surfaces at room temperature to prevent their heating by the powerful stored laser beams. The baffled solution has been simulated via COMSOL Multiphysics as a design tool. Finally, the parabolic mirror concept was experimentally validated with the results falling in close agreement with theoretical cooling calculations. The technique of directional radiative thermal correction can be reversed to image heat rings on the mirrors periphery to remotely and dynamically correct their radius of curvature without subjecting the mirror to relevant perturbations.

  19. The structure-directed effect of Al-based metal–organic frameworks on fabrication of alumina by thermal treatment

    International Nuclear Information System (INIS)

    Liu, Dandan; Dai, Fangna; Tang, Zhe; Liu, Yunqi; Liu, Chenguang

    2015-01-01

    Highlights: • We use Al-MOFs as precursor in the fabrication process of mesoporous alumina by thermal treatment. • The obtained mesoporous alumina has dual pore system and five-fold aluminum. • The aluminum building units in the precursor show structure-directed effect on the formation of alumina. - Abstract: In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state 27 Al nuclear magnetic resonance ( 27 Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ-alumina possesses a dual pore system and a large surface area (146 m 2 /g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina

  20. Mercury speciation and analysis in drinking water by stir bar sorptive extraction with in situ propyl derivatization and thermal desorption-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Ito, Rie; Kawaguchi, Migaku; Sakui, Norihiro; Honda, Hidehiro; Okanouchi, Noriya; Saito, Koichi; Nakazawa, Hiroyuki

    2008-10-31

    A method for mercury analysis and speciation in drinking water was developed, which involved stir bar sorptive extraction (SBSE) with in situ propyl derivatization and thermal desorption (TD)-GC-MS. Ten millilitre of tap water or bottled water was used. After a stir bar, pH adjustment agent and derivatization reagent were added, SBSE was performed. Then, the stir bar was subjected to TD-GC-MS. The detection limits were 0.01 ng mL(-1) (ethylmercury; EtHg), 0.02 ng mL(-1) (methylmercury; MeHg), and 0.2 ng mL(-1) (Hg(II) and diethylmercury (DiEtHg)). The method showed good linearity and correlation coefficients. The average recoveries of mercury species (n=5) in water samples spiked with 0.5, 2.0, and 6.0 ng mL(-1) mercury species were 93.1-131.1% (RSDmercury species in water samples.

  1. China action of "Cleanup Plan for Polychlorinated Biphenyls Burial Sites": emissions during excavation and thermal desorption of a capacitor-burial site.

    Science.gov (United States)

    Yang, Bing; Zhou, Lingli; Xue, Nandong; Li, Fasheng; Wu, Guanglong; Ding, Qiong; Yan, Yunzhong; Liu, Bo

    2013-10-01

    Scarce data are available so far on emissions in a given scenario for excavation and thermal desorption, a common practice, of soils contaminated with polychlorinated biphenyls (PCBs). As part of China action of "Cleanup Plan for PCBs Burial Sites", this study roughly estimated PCBs emissions in the scenario for a capacitor-burial site. The concentrations of total PCBs (22 congeners) in soils were in the range of 2.1-16,000μg/g with a mean of 2300μg/g, among the same order of magnitude as the highest values obtained in various PCBs-contaminated sites. Only six congeners belonging to Di-, Tri-, and Tetra-CBs were observed above limits of detection in air samples in the scenario, partially which can be estimated by the USEPA air emission model. Comparing concentrations and composition profiles of PCBs in the soil and air samples further indicated a leaked source of commercial PCBs formulations of trichlorobiphenyl (China PCB no. 1). The measures taken if any to mitigate the volatilization and movement of PCBs and to minimize worker exposure were discussed for improvements of the excavation practice. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Experimental and theoretical investigation of Fe-catalysis phenomenon in hydrogen thermal desorption form hydrocarbon plasma-discharge films from T-10 tokamak

    International Nuclear Information System (INIS)

    Stankevich, V.G.; Svechnikov, N.Y.; Lebedev, A.M.; Menshikov, K.A.; Kolbasov, B.N.; Sukhanov, L.P.

    2017-01-01

    A comprehensive study of hydrocarbon films obtained in the plasma discharge of large fusion facilities will allow the minimization of parasitic capture. The investigation of the effect of Fe impurities on D 2 thermal desorption (TD) from homogeneous CD x films (x ∼ 0.5) formed in the D-plasma discharge of the T-10 tokamak were carried out. The experimental TD spectra of the films showed 2 groups of peaks at 650-850 K and 900-1000 K for 2 adsorption states. The main result of the iron catalysis effect consists in the shift of the high-temperature peak by -24 K and in the increase in the fraction of the weakly bonded adsorption states. To describe the effect of iron impurities on TD of hydrogen isotopes, a structural cluster model based on the interaction of the Fe + ion with the 1,3-C 6 H 8 molecule was proposed. The potential energy surfaces of chemical reactions with the H 2 elimination were calculated using ab initio methods of quantum chemistry. It was established that the activation barrier of hydrogen TD is reduced by about 1 eV due to the interaction of the Fe + ion with the π-subsystem of the 1,3-C 6 H 8 molecule leading to a redistribution of the double bonds along the carbon system

  3. The Integration of a Small Thermal Desorption (TD) System for Air Monitoring into a Mobile Analytical Laboratory in France Used by the NRBC Emergency First Responder Police Organization

    International Nuclear Information System (INIS)

    Roberts, G. M.

    2007-01-01

    A mobile analytical laboratory has been developed in France by Thales Security Systems in conjunction with the French department of defense (DGA) to rapidly identify the composition of toxic substances released accidentally or by terrorist activity at a location of high civilian population density. Accurate and fast identification of toxic material is critical for first responder teams that attend an incident site. Based on this analysis defined decontamination protocols for contaminated people can be implemented, and specific medical treatment can be administered to those worst affected. Analysing samples with high technology instrumentation close to the point of release is therefore highly advantageous and is only possible with mobile analytical platforms. Transporting samples back to a central laboratory for analysis is not realistic due to time limitations. This paper looks at one particular aspect of analysis performed in this mobile multi-technique laboratory namely air monitoring for CW or TIC compounds. Air sampling and pre concentration is achieved using a small, innovative Thermal Desorption system (Unitytm) in combination with a gas chromatograph-mass spectroscopy system for the detection and identification of specific analytes. Implementation of the Unity TD system in the confines of this small mobile environment will be reviewed in this paper. (author)

  4. Experimental and theoretical investigation of Fe-catalysis phenomenon in hydrogen thermal desorption from hydrocarbon plasma-discharge films from T-10 tokama

    Science.gov (United States)

    Stankevich, Vladimir G.; Sukhanov, Leonid P.; Svechnikov, Nicolay Yu.; Lebedev, Alexey M.; Menshikov, Kostantin A.; Kolbasov, Boris N.

    2017-10-01

    Investigations of the effect of Fe impurities on D2 thermal desorption (TD) from homogeneous CDx films (x ˜ 0.5) formed in the D-plasma discharge of the T-10 tokamak were carried out. The experimental TD spectra of the films showed two groups of peaks at 650-850 K and 900-1000 K for two adsorption states. The main result of the iron catalysis effect consists in the shift of the high-temperature peak by -24 K and in the increase in the fraction of the weakly bonded adsorption states. To describe the effect of iron impurities on TD of hydrogen isotopes, a structural cluster model based on the interaction of the Fe+ ion with the 1,3-C6H8 molecule was proposed. The potential energy surfaces of chemical reactions with the H2 elimination were calculated using ab initio methods of quantum chemistry. It was established that the activation barrier of hydrogen TD is reduced by about 1 eV due to the interaction of the Fe+ ion with the π-subsystem of the 1,3-C6H8 molecule leading to a redistribution of the double bonds along the carbon system. Contribution to the topical issue "Plasma Sources and Plasma Processes (PSPP)"", edited by Luis Lemos Alves, Thierry Belmonte and Tiberiu Minea

  5. Hydrogen retention studies on lithiated tungsten exposed to glow discharge plasmas under varying lithiation environments using Thermal Desorption Spectroscopy and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A. de, E-mail: alfonso.decastro@ciemat.es [Fusion National Laboratory-CIEMAT, Av Complutense 40, 28040 Madrid (Spain); Valson, P. [Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald (Germany); Tabarés, F.L. [Fusion National Laboratory-CIEMAT, Av Complutense 40, 28040 Madrid (Spain)

    2017-04-15

    For the design of a Fusion Reactor based on a liquid lithium divertor target and a tungsten first wall at high temperature, the interaction of the wall material with plasmas of significant lithium content must be assessed, as issues like fuel retention, tungsten embrittlement and enhanced sputtering may represent a showstopper for the selection of the first wall material compatible with the presence of liquid metal divertor. In this work we address this topic for the first time at the laboratory level, hot W samples (100 °C) have been exposed to Glow Discharges of H{sub 2} or Li-seeded H{sub 2} followed by in situ thermal desorption studies (TDS) of the uptake of H{sub 2} on the samples. Pure and pre-lithiated tungsten was investigated in order to evaluate the differential effect of Li ion implantation on H retention. Global particle balance was also used for the determination of trapped H into the full W wall of the plasma chamber. A factor of 3-4 lower retention was deduced for samples and main W wall exposed to H/Li plasma than that measured on pre-lithiated W.

  6. Direct observation of thermal disorder and decomposition of black phosphorus

    Science.gov (United States)

    Yoo, Seung Jo; Kim, Heejin; Lee, Ji-Hyun; Kim, Jin-Gyu

    2018-02-01

    Theoretical research has been devoted to reveal the properties of black phosphorus as a two-dimensional nanomaterial, but little attention has been paid for the experimental characterization. In this study, the thermal disorder and decomposition of black phosphorus were examined using in situ heating transmission electron microscopy experiments. We observed that the breaking of crystallographic symmetry begins at 380 °C under vacuum condition, followed by the phosphorus evaporates after long-term heating at 400 °C. This decomposition process can be initiated by the surficial vacancy and proceeds toward both interlayer ([010]) and intralayer ([001]) directions. The results on the thermal behavior of black phosphorus provide useful guidance for thin film deposition and fabrication processes with black phosphorus.

  7. Thermal desorption studies of heterogeneous catalytic reactions--3. The stepwise mechanism of n-hexane dehydrocyclization (to benzene) over a Pt/Al/sub 2/O/sub 3/ catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, V V; Sklyarov, A V

    1978-12-01

    The interactions of n-hexane, benzene, and the possible intermediates of n-hexane dehydrocyclization by different mechanisms with a 0.68Vertical Bar3< Pt/..gamma..-Al/sub 2/O/sub 3/ catalyst and over pure ..gamma..-Al/sub 2/O/sub 3/ were studied by recording thermal desorption (TD) spectra of these compounds. The kinetic parameters, calculated from the TD data, for benzene formation from n-hexane, 1-hexene and 1,5-hexadiene coincided, suggesting a common reaction route involving these three species. TD spectra of methylcyclopentane indicated that this compound is not an important intermediate in n-hexane dehydrocyclization. These findings suggested that the process starts by two-step dehydrogenation of n-hexane to 1-hexene and 1,5-hexadiene and is followed by a rate-limiting step of hexadiene conversion. Formation of cyclohexadiene, the immediate precursor of benzene, occurs either by direct cyclization of hexadiene or via cyclohexene or hexatriene intermediates, but these routes are alternative rather than competing under the conditions studied.

  8. Enzyme Kinetics By Directly Imaging A Porous Silicon Microfluidic Reactor Using Desorption/Ionization on Silicon Mass Spectrometry

    NARCIS (Netherlands)

    Nichols, K.P.F.; Azoz, Seyla; Gardeniers, Johannes G.E.

    2008-01-01

    Enzyme kinetics were obtained in a porous silicon microfluidic channel by combining an enzyme and substrate droplet, allowing them to react and deposit a small amount of residue on the channel walls, and then analyzing this residue by directly ionizing the channel walls using a matrix assisted laser

  9. A New Generation of Thermal Desorption Technology Incorporating Multi Mode Sampling (NRT/DAAMS/Liquid Agent) for Both on and off Line Analysis of Trace Level Airbone Chemical Warfare Agents

    International Nuclear Information System (INIS)

    Roberts, G. M.

    2007-01-01

    A multi functional, twin-trap, electrically-cooled thermal desorption (TD) system (TT24-7) will be discussed for the analysis of airborne trace level chemical warfare agents. This technology can operate in both military environments (CW stockpile, or destruction facilities) and civilian locations where it is used to monitor for accidental or terrorist release of acutely toxic substances. The TD system interfaces to GC, GCMS or direct MS analytical platforms and provides for on-line continuous air monitoring with no sampling time blind spots and within a near real time (NRT) context. Using this technology enables on-line sub ppt levels of agent detection from a vapour sample. In addition to continuous sampling the system has the capacity for off-line single (DAAMS) tube analysis and the ability to receive an external liquid agent injection. The multi mode sampling functionality provides considerable flexibility to the TD system, allowing continuous monitoring of an environment for toxic substances plus the ability to analyse calibration standards. A calibration solution can be introduced via a conventional sampling tube on to either cold trap or as a direct liquid injection using a conventional capillary split/splitless injection port within a gas chromatograph. Low level (linearity) data will be supplied showing the TT24-7 analyzing a variety of CW compounds including free (underivitised) VX using the three sampling modes described above. Stepwise changes in vapor generated agent concentrations will be shown, and this is cross referenced against direct liquid agent introduction, and the tube sampling modes. This technology is in use today in several geographies around the world in both static and mobile analytical laboratories. (author)

  10. Rapid identification of pathogens directly from blood culture bottles by Bruker matrix-assisted laser desorption laser ionization-time of flight mass spectrometry versus routine methods.

    Science.gov (United States)

    Jamal, Wafaa; Saleem, Rola; Rotimi, Vincent O

    2013-08-01

    The use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of microorganisms directly from blood culture is an exciting dimension to the microbiologists. We evaluated the performance of Bruker SepsiTyper kit™ (STK) for direct identification of bacteria from positive blood culture. This was done in parallel with conventional methods. Nonrepetitive positive blood cultures from 160 consecutive patients were prospectively evaluated by both methods. Of 160 positive blood cultures, the STK identified 114 (75.6%) isolates and routine conventional method 150 (93%). Thirty-six isolates were misidentified or not identified by the kit. Of these, 5 had score of >2.000 and 31 had an unreliable low score of <1.7. Four of 8 yeasts were identified correctly. The average turnaround time using the STK was 35 min, including extraction steps and 30:12 to 36:12 h with routine method. The STK holds promise for timely management of bacteremic patients. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry of friction modifier additives analyzed directly from base oil solutions.

    Science.gov (United States)

    Widder, Lukas; Brennerb, Josef; Huttera, Herbert

    2014-01-01

    To develop new products and to apply measures of quality control quick and simple accessibility of additive composition in automo- tive lubrication is important. The aim of this study was to investigate the possibility of analyzing organic friction modifier additives by means of atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry [AP-MALDI-MS] from lubricant solu- tions without the use of additional separation techniques. Analyses of selected friction modifier ethoxylated tallow amines and oleic acid amide were compared using two ionization methods, positive-ion electrospray ionization (ESI) and AP-MALDI, using a LTQ Orbitrap mass spectrometer. Pure additives were characterized from solvent solutions, as well as from synthetic and mineral base oil mixtures. Detected ions of pure additive samples consisted mainly of [M + H]+, but also alkaLi metal adducts [M + Na]+ and [M + K]+ could be seen. Characterizations of blends of both friction modifiers from the base oil mixtures were carried out as well and showed significant inten- sities for several additive peaks. Thus, this work shows a method to directly analyze friction modifier additives used in the automotive industry from an oil blend via the use of AP-MALDI without any further separation steps. The method presented will further simplify the acquisition of data on lubricant composition and additives. Furthermore, it allows the perspective of analyzing additive reaction products directly from formulated oil blends.

  12. Evaluation of stir-bar sorptive extraction coupled with thermal desorption GC-MS for the detection of leachables from polymer single use systems to drugs.

    Science.gov (United States)

    Scherer, Nicole; Marcseková, Klaudia; Posset, Tobias; Winter, Gerhard

    2018-04-15

    Stir-bar Sorptive Extraction (SBSE) in combination with thermal desorption and gas chromatography-mass spectrometry (TD-GC-MS) is widely accepted as the gold-standard analysis method for trace amounts of organic substances, including leachables in aqueous matrices. Meanwhile, as far as pharmaceutical quality control in protein-based parenteral drugs is concerned, the use of SBSE analysis remains unexplored. Previous studies reported a strong influence of the matrix on the method's recovery. The scope of the present work was to fill in the unexplored territory in a threefold manner 1) by quantifying the effects that various matrices commonly found in pharmaceutical processing have on the recovery, 2) by comparing between different coating materials for stir bar (namely between polydimethylsiloxane (PDMS) material and ethylene-glycol (EG)-PDMS), and 3) by proposing a preparation step for stir-bar to mitigate inhibitory effects. The current study shows no inhibition of SBSE by protein matrices (p > 0.15). Further the influence of various drug matrices on the recovery of leachables with a log K o/w  ≥ 3.6 is negligible (-3.9 to 3.8%). In contrast, the inhibition effect caused by an alkaline media led to a recovery decrease of -42.9%. For leachables with a log K o/w   0.992). On average, the conventional PDMS coating resulted in a 28-fold higher signal-to-noise ratio compared to EG-PDMS. Furthermore, a broader range of leachables was detectable with the PDSM coating. Preceding stir-bar preparation consisting of a simple soaking step improved the enrichment by 14%, effectively lowering the limit of detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. [Target and non-target screening of volatile organic compounds in industrial exhaust gas using thermal desorption-gas chromatography-mass spectrometry].

    Science.gov (United States)

    Ma, Huilian; Jin, Jing; Li, Yun; Chen, Jiping

    2017-10-08

    A method of comprehensive screening of the target and non-target volatile organic compounds (VOCs) in industrial exhaust gas using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) has been developed. In this paper, two types of solid phase adsorption column were compared, and the Tenex SS TD Tube was selected. The analytes were enriched into the adsorption tube by constant flow sampling, and detected by TD-GC-MS in full scan mode. Target compounds were quantified by internal standard method, and the quantities of non-target compounds were calculated by response coefficient of toluene. The method detection limits (MDLs) for the 24 VOCs were 1.06 to 5.44 ng, and MDLs could also be expressed as 0.004 to 0.018 mg/m 3 assuming that the sampling volume was 300 mL. The average recoveries were in the range of 78.4% to 89.4% with the relative standard deviations (RSDs) of 3.9% to 14.4% ( n =7). The established analytical method was applied for the comprehensive screening of VOCs in a waste incineration power plant in Dalian city. Twenty-nine VOCs were identified. In these compounds, only five VOCs were the target compounds set in advance, which accounted for 26.7% of the total VOCs identified. Therefore, this study further proved the importance of screening non-target compounds in the analysis of VOCs in industrial exhaust gas, and has certain reference significance for the complete determination of VOCs distribution.

  14. Analysis of trimethoprim, lincomycin, sulfadoxin and tylosin in swine manure using laser diode thermal desorption-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Solliec, Morgan; Massé, Daniel; Sauvé, Sébastien

    2014-10-01

    A new extraction method coupled to a high throughput sample analysis technique was developed for the determination of four veterinary antibiotics. The analytes belong to different groups of antibiotics such as chemotherapeutics, sulfonamides, lincosamides and macrolides. Trimethoprim (TMP), sulfadoxin (SFX), lincomycin (LCM) and tylosin (TYL) were extracted from lyophilized manure using a sonication extraction. McIlvaine buffer and methanol (MeOH) were used as extraction buffers, followed by cation-exchange solid phase extraction (SPE) for clean-up. Analysis was performed by laser diode thermal desorption-atmospheric pressure chemical-ionization (LDTD-APCI) tandem mass spectrometry (MS/MS) with selected reaction monitoring (SRM) detection. The LDTD is a high throughput sample introduction method that reduces total analysis time to less than 15s per sample, compared to minutes when using traditional liquid chromatography (LC). Various SPE parameters were optimized after sample extraction: the stationary phase, the extraction solvent composition, the quantity of sample extracted and sample pH. LDTD parameters were also optimized: solvent deposition, carrier gas, laser power and corona discharge. The method limit of detection (MLD) ranged from 2.5 to 8.3 µg kg(-1) while the method limit of quantification (MLQ) ranged from 8.3 to 28µgkg(-1). Calibration curves in the manure matrix showed good linearity (R(2)≥ 0.996) for all analytes and the interday and intraday coefficients of variation were below 14%. Recoveries of analytes from manure ranged from 53% to 69%. The method was successfully applied to real manure samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Determination of Glycol Ethers in Ambient Air by Adsorption Sampling and Thermal Desorption with GC/MS Analysis: Performance Evaluation and Field Application

    Directory of Open Access Journals (Sweden)

    Young-Kyo Seo

    2012-01-01

    Full Text Available Some of glycol ethers, such as 2-methoxyethanol (2-ME and 2-ethoxyethanol (2-EE are known to be toxic and classified as hazardous air pollutants in USA, Japan and Germany. In Korea, however, there has been no study conducted so far for these compounds in ambient air. In addition, no clear methodologies for the measurement of glycol ethers have been yet established. We carried out this study to evaluate a sampling and analytical method for the determination of glycol ethers, in ambient air samples collected in specific industrial areas of South Korea. To measure glycol ethers, adsorption sampling and thermal desorption with GC/MS analysis were used in this study. The analytical method showed good repeatability, linearity and sensitivity. The lower detection limits were estimated to be approximately 0.3∼0.5 ppb. Based on storage tests, it was suggested that samples should be analyzed within two weeks. It was also demonstrated that this method can be used for the simultaneous measurement of glycol ethers and other aromatic VOCs such as benzene, toluene, and xylenes. Field sampling campaign was carried out at 2 sites, located in a large industrial area, from October 2006 to June 2007, and a total of 480 samples were collected seasonally. Among them, 2-ME was not detected from any samples, while 2-EE and 2-Ethyloxyethylacetate (2-EEA were found in 7 and 70 samples, respectively. The measured concentrations of 2-EE and 2-EEA for samples were ranged from 0.7-2.5 ppb and from 0.5-10.5 ppb, respectively. To our knowledge, this is the first measurement report for glycol ethers in the ambient atmosphere not only in Korea but also the rest of the world.

  16. Analysis of the technique Thermal Desorption Spectroscopy (TDS) and its Application for the Characterization of Metal -Hydrogen Systems; Analisis de la Tecnica Espectroscopia de Desorcion Termica (TDS) y su Applicacion para la Caracterizacion de Sistemas Metal-Hydrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Castro, F J [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina)

    2000-07-01

    We present the theoretical and experimental developments made to study the desorption of hydrogen from metallic samples by Thermal Desorption Spectroscopy (TDS). With this technique gas desorption is stimulated by the programmed heating of the sample. To perform the study we set up a newly designed equipment and develop theoretical models of the kinetic processes involved. The equipment and the models are used to analyze the desorption process in a real system. We begin by analyzing the models developed to interpret the results of the experiments. These models considersimultaneously bulk diffusion and surface reaction processes in metal-hydrogen systems with one or two thermodynamic phases. We present numerical results, computer simulations and analytical approximations of the original models. Based on these results we analyze the main features of the spectra for the different relevant kinetic processes, and determine the changes induced in them when material parameters (activation energies, geometry) or experimental parameters (heating speed, initial concentration) are modified.We present the original equipment, designed and constructed during this work to perform the TDS experiments. We describe its main characteristics, its components, its range of operation and its sensibility. We also offer an analysis of the background spectrum. We use the Pd-H system to test the equipment and the models. The samples chosen, powders, granules, foils and wires, were previously characterized to analyze their composition, their morphology and their characteristic size. We show the results of Scanning Electron Microscopy (SEM) observation, X ray diffraction (XRD) and Auger Electron Spectroscopy (AES) analysis.We then present and analyze in depth the experimental desorption spectra of the palladium powder. Based on the analysis we determine the rate limiting step for desorption and the characteristic activation energies. When the system is on the b phase (hydride) the rate

  17. Gold nanoparticles bridging infra-red spectroscopy and laser desorption/ionization mass spectrometry for direct analysis of over-the-counter drug and botanical medicines.

    Science.gov (United States)

    Chau, Siu-Leung; Tang, Ho-Wai; Ng, Kwan-Ming

    2016-05-05

    With a coating of gold nanoparticles (AuNPs), over-the-counter (OTC) drugs and Chinese herbal medicine granules in KBr pellets could be analyzed by Fourier Transform Infra-red (FT-IR) spectroscopy and Surface-assisted Laser Desorption/Ionization mass spectrometry (SALDI-MS). FT-IR spectroscopy allows fast detection of major active ingredient (e.g., acetaminophen) in OTC drugs in KBr pellets. Upon coating a thin layer of AuNPs on the KBr pellet, minor active ingredients (e.g., noscapine and loratadine) in OTC drugs, which were not revealed by FT-IR, could be detected unambiguously using AuNPs-assisted LDI-MS. Moreover, phytochemical markers of Coptidis Rhizoma (i.e. berberine, palmatine and coptisine) could be quantified in the concentrated Chinese medicine (CCM) granules by the SALDI-MS using standard addition method. The quantitative results matched with those determined by high-performance liquid chromatography with ultraviolet detection. Being strongly absorbing in UV yet transparent to IR, AuNPs successfully bridged FT-IR and SALDI-MS for direct analysis of active ingredients in the same solid sample. FT-IR allowed the fast analysis of major active ingredient in drugs, while SALDI-MS allowed the detection of minor active ingredient in the presence of excipient, and also quantitation of phytochemicals in herbal granules. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Discrimination of Bacillus anthracis Spores by Direct in-situ Analysis of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

    International Nuclear Information System (INIS)

    Jeong, Youngsu; Lee, Jonghee; Kim, Seongsoo

    2013-01-01

    The rapid and accurate identification of biological agents is a critical step in the case of bio-terror and biological warfare attacks. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been widely used for the identification of microorganisms. In this study, we describe a method for the rapid and accurate discrimination of Bacillus anthracis spores using MALDI-TOF MS. Our direct in-situ analysis of MALDI-TOF MS does not involve subsequent high-resolution mass analyses and sample preparation steps. This method allowed the detection of species-specific biomarkers from each Bacillus spores. Especially, B. anthracis spores had specific biomarker peaks at 2503, 3089, 3376, 6684, 6698, 6753, and 6840 m/z. Cluster and PCA analyses of the mass spectra of Bacillus spores revealed distinctively separated clusters and within-groups similarity. Therefore, we believe that this method is effective in the real-time identification of biological warfare agents such as B. anthracis as well as other microorganisms in the field

  19. Identification of pathogenic microorganisms directly from positive blood vials by matrix-assisted laser desorption/ionization time of flight mass spectrometry

    DEFF Research Database (Denmark)

    Nonnemann, Bettina; Tvede, Michael; Bjarnsholt, Thomas

    2013-01-01

    Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is a promising and fast method for identifying fungi and bacteria directly from positive blood cultures. Various pre-treatment methods for MALDI-TOF MS identification have been reported for this purpose. In......-house results for identification of bacterial colonies by MALDI-TOF MS using a cut-off score of 1.5 did not reduce the diagnostic accuracy compared with the recommended cut-off score of 1.8. A 3-month consecutive study of positive blood cultures was carried out in our laboratory to evaluate whether...... the Sepsityper™ Kit (Bruker Daltonics) with Biotyper 2.0 software could be used as a fast diagnostic tool for bacteria and fungi and whether a 1.5 cut-off score could improve species identification compared with the recommended score of 1.8. Two hundred and fifty-six positive blood vials from 210 patients and 19...

  20. Direct identification of bacteria in blood culture by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a new methodological approach.

    Science.gov (United States)

    Kroumova, Vesselina; Gobbato, Elisa; Basso, Elisa; Mucedola, Luca; Giani, Tommaso; Fortina, Giacomo

    2011-08-15

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has recently been demonstrated to be a powerful tool for the rapid identification of bacteria from growing colonies. In order to speed up the identification of bacteria, several authors have evaluated the usefulness of this MALDI-TOF MS technology for the direct and quick identification bacteria from positive blood cultures. The results obtained so far have been encouraging but have also shown some limitations, mainly related to the bacterial growth and to the presence of interference substances belonging to the blood cultures. In this paper, we present a new methodological approach that we have developed to overcome these limitations, based mainly on an enrichment of the sample into a growing medium before the extraction process, prior to mass spectrometric analysis. The proposed method shows important advantages for the identification of bacterial strains, yielding an increased identification score, which gives higher confidence in the results. Copyright © 2011 John Wiley & Sons, Ltd.

  1. Discrimination of Bacillus anthracis Spores by Direct in-situ Analysis of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Youngsu; Lee, Jonghee; Kim, Seongsoo [Agency for Defense Development, Daejeon (Korea, Republic of)

    2013-09-15

    The rapid and accurate identification of biological agents is a critical step in the case of bio-terror and biological warfare attacks. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been widely used for the identification of microorganisms. In this study, we describe a method for the rapid and accurate discrimination of Bacillus anthracis spores using MALDI-TOF MS. Our direct in-situ analysis of MALDI-TOF MS does not involve subsequent high-resolution mass analyses and sample preparation steps. This method allowed the detection of species-specific biomarkers from each Bacillus spores. Especially, B. anthracis spores had specific biomarker peaks at 2503, 3089, 3376, 6684, 6698, 6753, and 6840 m/z. Cluster and PCA analyses of the mass spectra of Bacillus spores revealed distinctively separated clusters and within-groups similarity. Therefore, we believe that this method is effective in the real-time identification of biological warfare agents such as B. anthracis as well as other microorganisms in the field.

  2. Direct identification of bacteria in positive blood culture bottles by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Bernard La Scola

    Full Text Available BACKGROUND: With long delays observed between sampling and availability of results, the usefulness of blood cultures in the context of emergency infectious diseases has recently been questioned. Among methods that allow quicker bacterial identification from growing colonies, matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF mass spectrometry was demonstrated to accurately identify bacteria routinely isolated in a clinical biology laboratory. In order to speed up the identification process, in the present work we attempted bacterial identification directly from blood culture bottles detected positive by the automate. METHODOLOGY/PRINCIPAL FINDINGS: We prospectively analysed routine MALDI-TOF identification of bacteria detected in blood culture by two different protocols involving successive centrifugations and then lysis by trifluoroacetic acid or formic acid. Of the 562 blood culture broths detected as positive by the automate and containing one bacterial species, 370 (66% were correctly identified. Changing the protocol from trifluoroacetic acid to formic acid improved identification of Staphylococci, and overall correct identification increased from 59% to 76%. Lack of identification was observed mostly with viridans streptococci, and only one false positive was observed. In the 22 positive blood culture broths that contained two or more different species, only one of the species was identified in 18 samples, no species were identified in two samples and false species identifications were obtained in two cases. The positive predictive value of bacterial identification using this procedure was 99.2%. CONCLUSIONS/SIGNIFICANCE: MALDI-TOF MS is an efficient method for direct routine identification of bacterial isolates in blood culture, with the exception of polymicrobial samples and viridans streptococci. It may replace routine identification performed on colonies, provided improvement for the specificity of blood culture

  3. Direct identification of pathogens from positive blood cultures using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Rodríguez-Sánchez, B; Sánchez-Carrillo, C; Ruiz, A; Marín, M; Cercenado, E; Rodríguez-Créixems, M; Bouza, E

    2014-07-01

    In recent years, matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has proved a rapid and reliable method for the identification of bacteria and yeasts that have already been isolated. The objective of this study was to evaluate this technology as a routine method for the identification of microorganisms directly from blood culture bottles (BCBs), before isolation, in a large collection of samples. For this purpose, 1000 positive BCBs containing 1085 microorganisms have been analysed by conventional phenotypic methods and by MALDI-TOF MS. Discrepancies have been resolved using molecular methods: the amplification and sequencing of the 16S rRNA gene or the Superoxide Dismutase gene (sodA) for streptococcal isolates. MALDI-TOF predicted a species- or genus-level identification of 81.4% of the analysed microorganisms. The analysis by episode yielded a complete identification of 814 out of 1000 analysed episodes (81.4%). MALDI-TOF identification is available for clinicians within hours of a working shift, as oppose to 18 h later when conventional identification methods are performed. Moreover, although further improvement of sample preparation for polymicrobial BCBs is required, the identification of more than one pathogen in the same BCB provides a valuable indication of unexpected pathogens when their presence may remain undetected in Gram staining. Implementation of MALDI-TOF identification directly from the BCB provides a rapid and reliable identification of the causal pathogen within hours. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

  4. Development of a rapid and simplified protocol for direct bacterial identification from positive blood cultures by using matrix assisted laser desorption ionization time-of- flight mass spectrometry.

    Science.gov (United States)

    Jakovljev, Aleksandra; Bergh, Kåre

    2015-11-06

    Bloodstream infections represent serious conditions carrying a high mortality and morbidity rate. Rapid identification of microorganisms and prompt institution of adequate antimicrobial therapy is of utmost importance for a successful outcome. Aiming at the development of a rapid, simplified and efficient protocol, we developed and compared two in-house preparatory methods for the direct identification of bacteria from positive blood culture flasks (BD BACTEC FX system) by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI TOF MS). Both methods employed saponin and distilled water for erythrocyte lysis. In method A the cellular pellet was overlaid with formic acid on the MALDI TOF target plate for protein extraction, whereas in method B the pellet was exposed to formic acid followed by acetonitrile prior to placing on the target plate. Best results were obtained by method A. Direct identification was achieved for 81.9 % and 65.8 % (50.3 % and 26.2 % with scores >2.0) of organisms by method A and method B, respectively. Overall concordance with final identification was 100 % to genus and 97.9 % to species level. By applying a lower cut-off score value, the levels of identification obtained by method A and method B increased to 89.3 % and 77.8 % of organisms (81.9 % and 65.8 % identified with scores >1.7), respectively. Using the lowered score criteria, concordance with final results was obtained for 99.3 % of genus and 96.6 % of species identifications. The reliability of results, rapid performance (approximately 25 min) and applicability of in-house method A have contributed to implementation of this robust and cost-effective method in our laboratory.

  5. Direct identification of bacteria in positive blood culture bottles by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry.

    Science.gov (United States)

    La Scola, Bernard; Raoult, Didier

    2009-11-25

    With long delays observed between sampling and availability of results, the usefulness of blood cultures in the context of emergency infectious diseases has recently been questioned. Among methods that allow quicker bacterial identification from growing colonies, matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry was demonstrated to accurately identify bacteria routinely isolated in a clinical biology laboratory. In order to speed up the identification process, in the present work we attempted bacterial identification directly from blood culture bottles detected positive by the automate. We prospectively analysed routine MALDI-TOF identification of bacteria detected in blood culture by two different protocols involving successive centrifugations and then lysis by trifluoroacetic acid or formic acid. Of the 562 blood culture broths detected as positive by the automate and containing one bacterial species, 370 (66%) were correctly identified. Changing the protocol from trifluoroacetic acid to formic acid improved identification of Staphylococci, and overall correct identification increased from 59% to 76%. Lack of identification was observed mostly with viridans streptococci, and only one false positive was observed. In the 22 positive blood culture broths that contained two or more different species, only one of the species was identified in 18 samples, no species were identified in two samples and false species identifications were obtained in two cases. The positive predictive value of bacterial identification using this procedure was 99.2%. MALDI-TOF MS is an efficient method for direct routine identification of bacterial isolates in blood culture, with the exception of polymicrobial samples and viridans streptococci. It may replace routine identification performed on colonies, provided improvement for the specificity of blood culture broths growing viridans streptococci is obtained in the near future.

  6. Determination of a wide range of volatile organic compounds in ambient air using multisorbent adsorption/thermal desorption and gas chromatography/mass spectrometry

    Science.gov (United States)

    Pankow, J.F.; Luo, W.; Isabelle, L.M.; Bender, D.A.; Baker, R.J.

    1998-01-01

    Adsorption/thermal desorption with multisorbent air-sampling cartridges was developed for the determination of 87 method analytes including halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. The volatilities of the compounds ranged from that of dichlorofluoromethane (CFC12) to that of 1,2,3- trichlorobenzene. The eight most volatile compounds were determined using a 1.5-L air sample and a sample cartridge containing 50 mg of Carbotrap B and 280 mg of Carboxen 1000; the remaining 79 compounds were determined using a 5-L air sample and a cartridge containing 180 mg of Carbotrap B and 70 mg of Carboxen 1000. Analysis and detection were by gas chromatography/mass spectrometry. The minimum detectable level (MDL) concentration values ranged from 0.01 parts per billion by volume (ppbv) for chlorobenzene to 0.4 ppbv for bromomethane; most of the MDL values were in the range 0.02-0.06 ppbv. No breakthrough was detected with the prescribed sample volumes. Analyte stability on the cartridges was very good. Excellent recoveries were obtained with independent check standards. Travel spike recoveries ranged from 90 to 110% for 72 of the 87 compounds. The recoveries were less than 70% for bromomethane and chloroethene and for a few compounds such as methyl acetate that are subject to losses by hydrolysis; the lowest travel spike recovery was obtained for bromomethane (62%). Blank values for all compounds were either below detection or very low. Ambient atmospheric sampling was conducted in New Jersey from April to December, 1997. Three sites characterized by low, moderate, and high densities of urbanization/traffic were sampled. The median detected concentrations of the compounds were either similar at all three sites (as with the chlorofluorocarbon compounds) or increased with the density of urbanization/traffic (as with dichloromethane, MTBE, benzene, and toluene). For toluene, the median detected

  7. Nature of unresolved complex mixture in size-distributed emissions from residential wood combustion as measured by thermal desorption-gas chromatography-mass spectrometry

    Science.gov (United States)

    Hays, Michael D.; Smith, N. Dean; Dong, Yuanji

    2004-08-01

    Unresolved complex mixture (UCM) is an analytical artifact of gas chromatographs of combustion source-related fine aerosol extracts. In this study the UCM is examined in size-resolved fine aerosol emissions from residential wood combustion. The aerosols are sorted by size in an electrical low-pressure impactor (ELPI) and subsequently analyzed by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). A semiquantitative system for predicting the branched alkane, cycloalkane, alkylbenzene, C3-, C4-, C5-alkylbenzene, methylnaphthalene, C3-, C4-, C5-alkylnaphthalene, methylphenanthrene C2-, C3-alkylphenanthrene, and dibenzothiophene concentrations in the UCM is introduced. Analysis by TD/GS/MS detects UCM on each ELPI stage for all six combustion tests. The UCM baseline among the different fuel types is variable. In particular, the UCM of Pseudotsuga sp. is enriched in later-eluting compounds of lower volatility. A high level of reproducibility is achieved in determining UCM areas. UCM fractions (UCM ion area/total extracted ion chromatograph area) by individual ELPI stage return a mean relative standard deviation of 19.1% over the entire combustion test set, indicating a highly consistent UCM fraction across the ELPI size boundaries. Among the molecular ions investigated, branched alkane (m/z 57) and dibenzothiophene (m/z 212 and 226) constituents are most abundant in UCM emissions from RWC, collectively accounting for 64-95% of the targeted chemical species. The total UCM emissions span 446-756 mg/kg of dry biomass burned and correspond to an upper limit of 7.1% of the PM2.5 mass. The UCM emissions are primarily accumulation mode (0.1 μm ≤ aerodynamic diameter (da) ≤ 1 μm), with a geometric mean diameter (dg) range of 120.3-518.4 nm. UCM in PM2.5 is chemically asymmetric (shifted to finer da), typically clustering at da ≤ 1 μm. Measurable shifts in dg and changes in distribution widths (σg) on an intratest basis suggest that the particle density

  8. Air Emissions Sampling from Vacuum Thermal Desorption for Mixed Wastes Designated with a Combustion Treatment Code for the Energy Solutions LLC Mixed Waste Facility

    International Nuclear Information System (INIS)

    Christensen, M.E.; Willoughby, O.H.

    2009-01-01

    EnergySolutions LLC is permitted by the State of Utah to treat organically-contaminated Mixed Waste by a vacuum thermal desorption (VTD) treatment process at its Clive, Utah treatment, storage, and disposal facility. The VTD process separates organics from organically-contaminated waste by heating the material in an inert atmosphere, and captures them as concentrated liquid by condensation. The majority of the radioactive materials present in the feed to the VTD are retained with the treated solids; the recovered aqueous and organic condensates are not radioactive. This is generally true when the radioactivity is present in solid form such as inorganic salts, metals or metallic oxides. The exception is when volatile radioactive materials are present such as radon gas, tritium, or carbon-14 organic chemicals. Volatile radioactive materials are a small fraction of the feed material. On August 28, 2006, EnergySolutions submitted a request to the USEPA for a variance to the Land Disposal Restrictions (LDR) standards for wastes designated with the combustion treatment code (CMBST). The final rule granting a site specific treatment variance was effective June 13, 2008. This variance is an alternative treatment standard to treatment by CMBST required for these wastes under USEPA's rules. The State of Utah provides oversight of the VTD processing operations. A demonstration test for treating CMBST-coded wastes was performed on April 29, 2008 through May 1, 2008. Three separate process cycles were conducted during this test. Both solid/liquid samples and emission samples were collected each day during the demonstration test. To adequately challenge the unit, feed material was spiked with trichloroethylene, o-cresol, dibenzofuran, and coal tar. Emission testing was conducted by EnergySolutions' emissions test contractor and sampling for radioactivity within the off-gas was completed by EnergySolutions' Health Physics department. This report discusses the emission testing

  9. Survival and growth of Alfalfa (Medicago sativa l.) inoculated with an am fungus (Glomus intraradices) in contaminated soils treated with two different remediation technologies (bio-pile and thermal desorption)

    International Nuclear Information System (INIS)

    Norini, M.P.; Beguiristain, Th.; Leyval, C.

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAHs) represent a group of persistent and toxic soil pollutants that are of major public concern due to their mutagenic and carcinogenic property. Phyto-remediation is the use of plants and their associated microorganisms for remediation of polluted soils. Phyto-remediation could be used in conjunction with other remediation technologies to reduce the contamination to safe levels and maintain or restore soil physico-chemical and biological properties. Most plant species form mycorrhizas with symbiotic fungi. It was shown that AM fungi enhance survival and plant growth in PAH contaminated soils. Mycorrhizal fungi also enhance the biotransformation or biodegradation of PAH, although the effect differed between soils. A rhizosphere and myco-rhizosphere gradient of PAH concentrations was observed, with decreased PAH concentration with decreased distance to roots. Different microbial communities were found in the rhizosphere of AM and non-mycorrhizal plants in comparison to bulk soil, suggesting that AM could affect PAH degradation by changing microbial communities. We investigated the effect of mycorrhizal fungi and nutrients on the ability of alfalfa to grow on soil contaminated with PAHs before and after two remediation treatments. We used soil from an industrial site (Homecourt, North East part of France) highly contaminated with PAH (2000 mg kg -1 ), which has been partially treated by two different remediation technologies (bio-pile and thermal desorption). The bio-pile treatment consisted of piling the contaminated soil with stimulation of aerobic microbial activity by aeration and addition of nutrient solution, and reduced PAH concentration to around 300 mg kg-1. With the thermal desorption treatment the soil was heated to around 500 deg. C so that PAH vaporized and were separated from the soil. The residual PAH concentration in soil was 40 mg kg -1 . Treated and non-treated contaminated soil was planted with alfalfa (Medicago

  10. Species identification of Aspergillus, Fusarium and Mucorales with direct surface analysis by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    De Carolis, E; Posteraro, B; Lass-Flörl, C; Vella, A; Florio, A R; Torelli, R; Girmenia, C; Colozza, C; Tortorano, A M; Sanguinetti, M; Fadda, G

    2012-05-01

    Accurate species discrimination of filamentous fungi is essential, because some species have specific antifungal susceptibility patterns, and misidentification may result in inappropriate therapy. We evaluated matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for species identification through direct surface analysis of the fungal culture. By use of culture collection strains representing 55 species of Aspergillus, Fusarium and Mucorales, a reference database was established for MALDI-TOF MS-based species identification according to the manufacturer's recommendations for microflex measurements and MALDI BioTyper 2.0 software. The profiles of young and mature colonies were analysed for each of the reference strains, and species-specific spectral fingerprints were obtained. To evaluate the database, 103 blind-coded fungal isolates collected in the routine clinical microbiology laboratory were tested. As a reference method for species designation, multilocus sequencing was used. Eighty-five isolates were unequivocally identified to the species level (≥99% sequence similarity); 18 isolates producing ambiguous results at this threshold were initially rated as identified to the genus level only. Further molecular analysis definitively assigned these isolates to the species Aspergillus oryzae (17 isolates) and Aspergillus flavus (one isolate), concordant with the MALDI-TOF MS results. Excluding nine isolates that belong to the fungal species not included in our reference database, 91 (96.8%) of 94 isolates were identified by MALDI-TOF MS to the species level, in agreement with the results of the reference method; three isolates were identified to the genus level. In conclusion, MALDI-TOF MS is suitable for the routine identification of filamentous fungi in a medical microbiology laboratory. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

  11. Direct identification of bacteria from charcoal-containing blood culture bottles using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

    Science.gov (United States)

    Wüppenhorst, N; Consoir, C; Lörch, D; Schneider, C

    2012-10-01

    Several protocols for direct matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) from positive blood cultures are currently used to speed up the diagnostic process of bacteraemia. Identification rates are high and results are accurate for the BACTEC™ system and for charcoal-free bottles. Only a few studies have evaluated protocols for charcoal-containing BacT/ALERT bottles reaching substantially lower identification rates. We established a new protocol for sample preparation from aerobic and anaerobic positive charcoal-containing BacT/ALERT blood culture bottles and measured the protein profiles (n = 167). Then, we integrated this protocol in the routine workflow of our laboratory (n = 212). During the establishment of our protocol, 74.3 % of bacteria were correctly identified to the species level, in 23.4 %, no result and in 2.4 %, a false identification were obtained. Reliable criteria for correct species identification were a score value ≥1.400 and a best match on rank 1-3 of the same species. Identification rates during routine workflow were 77.8 % for correct identification, 20.8 % for not identified samples and 1.4 % for discordant identification. In conclusion, our results indicate that MALDI-TOF MS is possible, even from charcoal-containing blood cultures. Reliable criteria for correct species identification are a score value ≥1.400 and a best match on rank 1-3 of a single species.

  12. Direct bacterial identification in positive blood cultures by use of two commercial matrix-assisted laser desorption ionization-time of flight mass spectrometry systems.

    Science.gov (United States)

    Chen, Jonathan H K; Ho, Pak-Leung; Kwan, Grace S W; She, Kevin K K; Siu, Gilman K H; Cheng, Vincent C C; Yuen, Kwok-Yung; Yam, Wing-Cheong

    2013-06-01

    Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of bacteria and fungi was recently introduced in microbiology laboratories. This technology could greatly improve the clinical management of patients and guidance for chemotherapy. In this study, we used a commercial MALDI Sepsityper extraction method to evaluate the performance of two commercial MALDI-TOF MS systems, the Vitek MS IVD (bioMérieux) and the Microflex LT Biotyper (Bruker Daltonics) for direct bacterial identification in positive blood cultures. In 181 monomicrobial cultures, both systems generated genus to species level identifications for >90% of the specimens (Biotyper, 177/181 [97.8%]; Vitek MS IVD, 167/181 [92.3%]). Overall, the Biotyper system generated significantly more accurate identifications than the Vitek MS IVD system (P = 0.016; 177 versus 167 out of 181 specimens). The Biotyper system identified the minority species among polymicrobial blood cultures. We also compared the performance of an in-house extraction method with that of the Sepsityper on both MALDI-TOF MS systems. The in-house method generated more correct identifications at the genus level than the Sepsityper (96.7% versus 93.5%) on the Biotyper system, whereas the two methods exhibited the same performance level (88.0% versus 88.0%) on the Vitek MS IVD system. Our study confirmed the practical advantages of MALDI-TOF MS, and our in-house extraction method reduced the reagent cost to $1 per specimen, with a shorter turnaround time of 3 h, which is highly cost-effective for a diagnostic microbiology service.

  13. Experiment on direct nn scattering - The radiation-induced outgassing complication

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, S.L., E-mail: sstephen@gettysburg.edu [Gettysburg College, Gettysburg, PA 17325 (United States); Crawford, B.E. [Gettysburg College, Gettysburg, PA 17325 (United States); Furman, W.I.; Lychagin, E.V.; Muzichka, A.Yu.; Nekhaev, G.V.; Sharapov, E.I.; Shvetsov, V.N.; Strelkov, A.V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Levakov, B.G.; Lyzhin, A.E.; Chernukhin, Yu.I. [Russian Federal Nuclear Center - All Russian Research Institute of Technical Physics, P.O. Box 245, 456770 Snezhinsk (Russian Federation); Howell, C.R. [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G.E. [North Carolina State University, Raleigh, NC 27695-8202 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Showalter-Bucher, R.A. [Northeastern University, Boston, MA 02115 (United States)

    2012-12-01

    The first direct neutron-neutron scattering experiment using the YAGUAR pulsed reactor has yielded initial results. They show a unforeseen significant thermal neutron background as a result of radiation-induced desorption within the scattering chamber. Thermal neutrons are mostly scattering not from other neutrons but instead from the desorbed gas molecules. Analysis of the obtained neutron time-of-flight spectra suggests neutron scattering from H{sub 2} molecules. The presented desorption model agrees with our experimental value of the desorption yield {eta}{sub {gamma}}=0.02 molecules/gamma. Possible techniques to reduce the effect of the desorption background are presented.

  14. Identification of Blood Culture Isolates Directly from Positive Blood Cultures by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and a Commercial Extraction System: Analysis of Performance, Cost, and Turnaround Time

    OpenAIRE

    Lagacé-Wiens, Philippe R. S.; Adam, Heather J.; Karlowsky, James A.; Nichol, Kimberly A.; Pang, Paulette F.; Guenther, Jodi; Webb, Amanda A.; Miller, Crystal; Alfa, Michelle J.

    2012-01-01

    Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry represents a revolution in the rapid identification of bacterial and fungal pathogens in the clinical microbiology laboratory. Recently, MALDI-TOF has been applied directly to positive blood culture bottles for the rapid identification of pathogens, leading to reductions in turnaround time and potentially beneficial patient impacts. The development of a commercially available extraction kit (Bruker Sepsit...

  15. An in-house assay is superior to Sepsityper for direct matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry identification of yeast species in blood cultures.

    Science.gov (United States)

    Bidart, Marie; Bonnet, Isabelle; Hennebique, Aurélie; Kherraf, Zine Eddine; Pelloux, Hervé; Berger, François; Cornet, Muriel; Bailly, Sébastien; Maubon, Danièle

    2015-05-01

    We developed an in-house assay for the direct identification, by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry, of yeasts in blood culture. Sixty-one representative strains from 12 species were analyzed in spiked blood cultures. Our assay accurately identified 95 of 107 (88.8%) positive blood cultures and outperformed the commercial Sepsityper kit (81.7% identification). Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. Direct analysis of triterpenes from high-salt fermented cucumbers using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI)

    Science.gov (United States)

    High-salt samples present a challenge to mass spectrometry (MS) analysis, particularly when electrospray ionization (ESI) is used, requiring extensive sample preparation steps such as desalting, extraction, and purification. In this study, infrared matrix-assisted laser desorption electrospray ioniz...

  17. Economic impact of latent heat thermal energy storage systems within direct steam generating solar thermal power plants with parabolic troughs

    International Nuclear Information System (INIS)

    Seitz, M.; Johnson, M.; Hübner, S.

    2017-01-01

    Highlights: • Integration of a latent heat thermal energy storage system into a solar direct steam generation power cycle. • Parametric study of solar field and storage size for determination of the optimal layout. • Evaluation of storage impact on the economic performance of the solar thermal power plant. • Economic comparison of new direct steam generation plant layout with state-of-the-art oil plant layout. - Abstract: One possible way to further reduce levelized costs of electricity of concentrated solar thermal energy is to directly use water/steam as the primary heat transfer fluid within a concentrated collector field. This so-called direct steam generation offers the opportunity of higher operating temperatures and better exergy efficiency. A technical challenge of the direct steam generation technology compared to oil-driven power cycles is a competitive storage technology for heat transfer fluids with a phase change. Latent heat thermal energy storages are suitable for storing heat at a constant temperature and can be used for direct steam generation power plants. The calculation of the economic impact of an economically optimized thermal energy storage system, based on a latent heat thermal energy storage system with phase change material, is the main focus of the presented work. To reach that goal, a thermal energy storage system for a direct steam generation power plant with parabolic troughs in the solar field was thermally designed to determine the boundary conditions. This paper discusses the economic impact of the designed thermal energy storage system based on the levelized costs of electricity results, provided via a wide parametric study. A state-of-the-art power cycle with a primary and a secondary heat transfer fluid and a two-tank thermal energy storage is used as a benchmark technology for electricity generation with solar thermal energy. The benchmark and direct steam generation systems are compared to each other, based respectively

  18. Direct detection of carbapenemase-associated proteins of Acinetobacter baumannii using nanodiamonds coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Chang, Kai-Chih; Chung, Chin-Yi; Yeh, Chen-Hsing; Hsu, Kuo-Hsiu; Chin, Ya-Ching; Huang, Sin-Siang; Liu, Bo-Rong; Chen, Hsi-An; Hu, Anren; Soo, Po-Chi; Peng, Wen-Ping

    2018-04-01

    The appearance and spread of carbapenem-resistant Acinetobacter baumannii (CRAB) pose a challenge for optimization of antibiotic therapies and outbreak preventions. The carbapenemase production can be detected through culture-based methods (e.g. Modified Hodge Test-MHT) and DNA based methods (e.g. Polymerase Chain Reaction-PCR). The culture-based methods are time-consuming, whereas those of PCR assays need only a few hours but due to its specificity, can only detect known genetic targets encoding carbapenem-resistance genes. Therefore, new approaches to detect carbapenemase-producing A. baumannii are of great importance. Here, we have developed a rapid and novel method using detonation nanodiamonds (DNDs) as a platform for concentration and extraction of A. baumannii carbapenemase-associated proteins prior to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS) analysis. To concentrate and extract the A. baumannii carbapenemase-associated proteins, we tested several protein precipitation conditions and found a 0.5% trifluoroacetic acid (TFA) solution within the bacterial suspension could result in strong ion signals with DNDs. A total of 66 A. baumannii clinical-isolates including 51 carbapenem-resistant strains and 15 carbapenem-susceptible strains were tested. Our result showed that among the 51 carbapenem-resistant strains 49 strains had a signal at m/z ~40,279 (±87); among the 15 carbapenem-susceptible strains, 4 strains showed a signal at m/z ~40,279. With on-diamond digestion, we confirmed that the captured protein at m/z ~40,279 was related to ADC family extended-spectrum class C beta-lactamase, from A. baumannii. Using this ADC family protein as a biomarker (m/z ~ 40,279) for carbapenem susceptibility testing of A. baumannii, the sensitivity and the specificity could reach 96% and 73% as compared to traditional imipenem susceptibility testing (MIC results). However, the sensitivity and specificity of this method

  19. Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, V V [Inst. Chem. Phys. Acad. Sci. U.S.S.R.; Sklyarov, A V; Gland, J

    1979-10-01

    Programed TD of n-heptane adsorbed on 0.6-3% by wt Pt/..gamma..-Al/sub 2/O/sub 3/ laboratory catalysts with different dispersities of the metallic phase showed the formation of toluene at 160/sup 0/-260/sup 0/C with spectral maxima at about 200/sup 0/ and 230/sup 0/C and a benzene desorption maxima at 300/sup 0/C. The desorption of both benzene and the high-temperature form of toluene decreased with decreased dispersity of the catalyst and was not observed with the catalyst characterized by an average Pt particle size of 1000 A. Toluene adsorbed on the same catalysts showed a TD peak of benzene at 300/sup 0/C. With commercial Pt/Al/sub 2/O/sub 3/ reforming catalysts, up to five toluene desorption peaks were observed at 200/sup 0/-360/sup 0/C, suggesting the presence of active sites with different activities and concentrations on the catalyst surface. Experiments on TD of deuterated n-heptane suggested different reaction mechanisms associated with different types of active sites and the formation of low- and high-temperature forms of toluene. Only the latter had a maximum coinciding with a TD peak of D/sub 2/ (240/sup 0/C), probably formed by dehydrogenation of adsorbed diene or olefin intermediates.

  20. Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Idelevich, Evgeny A; Grünastel, Barbara; Becker, Karsten

    2017-01-01

    Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. Copyright © 2016 American Society for Microbiology.

  1. Measurement of breakthrough volumes of volatile chemical warfare agents on a poly(2,6-diphenylphenylene oxide)-based adsorbent and application to thermal desorption-gas chromatography/mass spectrometric analysis.

    Science.gov (United States)

    Kanamori-Kataoka, Mieko; Seto, Yasuo

    2015-09-04

    To establish adequate on-site solvent trapping of volatile chemical warfare agents (CWAs) from air samples, we measured the breakthrough volumes of CWAs on three adsorbent resins by an elution technique using direct electron ionization mass spectrometry. The trapping characteristics of Tenax(®) TA were better than those of Tenax(®) GR and Carboxen(®) 1016. The latter two adsorbents showed non-reproducible breakthrough behavior and low VX recovery. The specific breakthrough values were more than 44 (sarin) L/g Tenax(®) TA resin at 20°C. Logarithmic values of specific breakthrough volume for four nerve agents (sarin, soman, tabun, and VX) showed a nearly linear correlation with the reciprocals of their boiling points, but the data point of sulfur mustard deviated from this linear curve. Next, we developed a method to determine volatile CWAs in ambient air by thermal desorption-gas chromatography (TD-GC/MS). CWA solutions that were spiked into the Tenax TA(®) adsorbent tubes were analyzed by a two-stage TD-GC/MS using a Tenax(®) TA-packed cold trap tube. Linear calibration curves for CWAs retained in the resin tubes were obtained in the range between 0.2pL and 100pL for sarin, soman, tabun, cyclohexylsarin, and sulfur mustard; and between 2pL and 100pL for VX and Russian VX. We also examined the stability of CWAs in Tenax(®) TA tubes purged with either dry or 50% relative humidity air under storage conditions at room temperature or 4°C. More than 80% sarin, soman, tabun, cyclohexylsarin, and sulfur mustard were recovered from the tubes within 2 weeks. In contrast, the recoveries of VX and Russian VX drastically reduced with storage time at room temperature, resulting in a drop to 10-30% after 2 weeks. Moreover, we examined the trapping efficiency of Tenax TA(®) adsorbent tubes for vaporized CWA samples (100mL) prepared in a 500mL gas sampling cylinder. In the concentration range of 0.2-2.5mg/m(3), >50% of sarin, soman, tabun, cyclohexylsarin, and HD were

  2. Multi-Directional Optical Diagnostics of Thermal Plasma Jets

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Chvála, František; Šonský, Jiří; Gruber, Jan

    2008-01-01

    Roč. 19, č. 1 (2008), s. 1-6 ISSN 0957-0233 R&D Projects: GA ČR(CZ) GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * optical diagnostics * Radon transform Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.493, year: 2008

  3. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, David C. [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  4. Directed Thermal Diffusions through Metamaterial Source Illusion with Homogeneous Natural Media

    Directory of Open Access Journals (Sweden)

    Guoqiang Xu

    2018-04-01

    Full Text Available Owing to the utilization of transformation optics, many significant research and development achievements have expanded the applications of illusion devices into thermal fields. However, most of the current studies on relevant thermal illusions used to reshape the thermal fields are dependent of certain pre-designed geometric profiles with complicated conductivity configurations. In this paper, we propose a methodology for designing a new class of thermal source illusion devices for achieving directed thermal diffusions with natural homogeneous media. The employments of the space rotations in the linear transformation processes allow the directed thermal diffusions to be independent of the geometric profiles, and the utilization of natural homogeneous media improve the feasibility. Four schemes, with fewer types of homogeneous media filling the functional regions, are demonstrated in transient states. The expected performances are observed in each scheme. The related performance are analyzed by comparing the thermal distribution characteristics and the illusion effectiveness on the measured lines. The findings obtained in this paper see applications in the development of directed diffusions with minimal thermal loss, used in novel “multi-beam” thermal generation, thermal lenses, solar receivers, and waveguide.

  5. An infrared measurement of chemical desorption from interstellar ice analogues

    Science.gov (United States)

    Oba, Y.; Tomaru, T.; Lamberts, T.; Kouchi, A.; Watanabe, N.

    2018-03-01

    In molecular clouds at temperatures as low as 10 K, all species except hydrogen and helium should be locked in the heterogeneous ice on dust grain surfaces. Nevertheless, astronomical observations have detected over 150 different species in the gas phase in these clouds. The mechanism by which molecules are released from the dust surface below thermal desorption temperatures to be detectable in the gas phase is crucial for understanding the chemical evolution in such cold clouds. Chemical desorption, caused by the excess energy of an exothermic reaction, was first proposed as a key molecular release mechanism almost 50 years ago1. Chemical desorption can, in principle, take place at any temperature, even below the thermal desorption temperature. Therefore, astrochemical network models commonly include this process2,3. Although there have been a few previous experimental efforts4-6, no infrared measurement of the surface (which has a strong advantage to quantify chemical desorption) has been performed. Here, we report the first infrared in situ measurement of chemical desorption during the reactions H + H2S → HS + H2 (reaction 1) and HS + H → H2S (reaction 2), which are key to interstellar sulphur chemistry2,3. The present study clearly demonstrates that chemical desorption is a more efficient process for releasing H2S into the gas phase than was previously believed. The obtained effective cross-section for chemical desorption indicates that the chemical desorption rate exceeds the photodesorption rate in typical interstellar environments.

  6. Oxygen transport and GeO2 stability during thermal oxidation of Ge

    Science.gov (United States)

    da Silva, S. R. M.; Rolim, G. K.; Soares, G. V.; Baumvol, I. J. R.; Krug, C.; Miotti, L.; Freire, F. L.; da Costa, M. E. H. M.; Radtke, C.

    2012-05-01

    Oxygen transport during thermal oxidation of Ge and desorption of the formed Ge oxide are investigated. Higher oxidation temperatures and lower oxygen pressures promote GeO desorption. An appreciable fraction of oxidized Ge desorbs during the growth of a GeO2 layer. The interplay between oxygen desorption and incorporation results in the exchange of O originally present in GeO2 by O from the gas phase throughout the oxide layer. This process is mediated by O vacancies generated at the GeO2/Ge interface. The formation of a substoichiometric oxide is shown to have direct relation with the GeO desorption.

  7. Universal scaling for biomolecule desorption induced by swift heavy ions

    International Nuclear Information System (INIS)

    Szenes, G.

    2005-01-01

    A thermal activation mechanism is proposed for the desorption of biomolecules. Good agreement is found with the experiments in a broad range of the electronic stopping power. The activation energies of desorption U are 0.33, 1.57 and 5.35 eV for positive, negative and neutral leucine molecules, respectively, and 2.05 eV for positive ergosterol molecules. The desorption of valine clusters is analyzed. The magnitude of the specific heat shows that the internal degrees of freedom are not excited up to the moment of desorption. The effect of irradiation temperature and of ion velocity on the desorption yield is discussed on the basis of the author's model. The scaling function derived in the model for the desorption of biomolecules is applied also to the sputtering of SiO 2 and U = 0.42 eV is obtained

  8. Differential and directional effects of perfusion on electrical and thermal conductivities in liver.

    Science.gov (United States)

    Podhajsky, Ronald J; Yi, Ming; Mahajan, Roop L

    2009-01-01

    Two different measurement probes--an electrical probe and a thermal conductivity probe--were designed, fabricated, calibrated, and used in experimental studies on a pig liver model that was designed to control perfusion rates. These probes were fabricated by photolithography and mounted in 1.5-mm diameter catheters. We measured the local impedance and thermal conductivity, respectively, of the artificially perfused liver at different flow rates and, by rotating the probes, in different directions. The results show that both the local electrical conductivity and the thermal conductivity varied location to location, that thermal conductivity increased with decreased distance to large blood vessels, and that significant directional differences exist in both electrical and thermal conductivities. Measurements at different perfusion rates demonstrated that both the local electrical and local thermal conductivities increased linearly with the square root of perfusion rate. These correlations may be of great value to many energy-based biomedical applications.

  9. Direct Estimation of Power Distribution in Reactors for Nuclear Thermal Space Propulsion

    Science.gov (United States)

    Aldemir, Tunc; Miller, Don W.; Burghelea, Andrei

    2004-02-01

    A recently proposed constant temperature power sensor (CTPS) has the capability to directly measure the local power deposition rate in nuclear reactor cores proposed for space thermal propulsion. Such a capability reduces the uncertainties in the estimated power peaking factors and hence increases the reliability of the nuclear engine. The CTPS operation is sensitive to the changes in the local thermal conditions. A procedure is described for the automatic on-line calibration of the sensor through estimation of changes in thermal .conditions.

  10. An Integrated Hot-Stage Microscope-Direct Analysis in Real Time-Mass Spectrometry System for Studying the Thermal Behavior of Materials.

    Science.gov (United States)

    Ashton, Gage P; Harding, Lindsay P; Parkes, Gareth M B

    2017-12-19

    This paper describes a new analytical instrument that combines a precisely temperature-controlled hot-stage with digital microscopy and Direct Analysis in Real Time-mass spectrometry (DART-MS) detection. The novelty of the instrument lies in its ability to monitor processes as a function of temperature through the simultaneous recording of images, quantitative color changes, and mass spectra. The capability of the instrument was demonstrated through successful application to four very varied systems including profiling an organic reaction, decomposition of silicone polymers, and the desorption of rhodamine B from an alumina surface. The multidimensional, real-time analytical data provided by this instrument allow for a much greater insight into thermal processes than could be achieved previously.

  11. Development of a direct push based in-situ thermal conductivity measurement system

    Science.gov (United States)

    Chirla, Marian Andrei; Vienken, Thomas; Dietrich, Peter; Bumberger, Jan

    2016-04-01

    Heat pump systems are commonly utilized in Europe, for the exploitation of the shallow geothermal potential. To guarantee a sustainable use of the geothermal heat pump systems by saving resources and minimizing potential negative impacts induced by temperature changes within soil and groundwater, new geothermal exploration methods and tools are required. The knowledge of the underground thermal properties is a necessity for a correct and optimum design of borehole heat exchangers. The most important parameter that indicates the performance of the systems is thermal conductivity of the ground. Mapping the spatial variability of thermal conductivity, with high resolution in the shallow subsurface for geothermal purposes, requires a high degree of technical effort to procure adequate samples for thermal analysis. A collection of such samples from the soil can disturb sample structure, so great care must be taken during collection to avoid this. Factors such as transportation and sample storage can also influence measurement results. The use of technologies like Thermal Response Test (TRT) require complex mechanical and electrical systems for convective heat transport in the subsurface and longer monitoring times, often three days. Finally, by using thermal response tests, often only one integral value is obtained for the entire coupled subsurface with the borehole heat exchanger. The common thermal conductivity measurement systems (thermal analyzers) can perform vertical thermal conductivity logs only with the aid of sample procurement, or by integration into a drilling system. However, thermal conductivity measurements using direct push with this type of probes are not possible, due to physical and mechanical limitations. Applying vertical forces using direct push technology, in order to penetrate the shallow subsurface, can damage the probe and the sensors systems. The aim of this study is to develop a new, robust thermal conductivity measurement probe, for direct

  12. Thermal analysis and two-directional air flow thermal management for lithium-ion battery pack

    Science.gov (United States)

    Yu, Kuahai; Yang, Xi; Cheng, Yongzhou; Li, Changhao

    2014-12-01

    Thermal management is a routine but crucial strategy to ensure thermal stability and long-term durability of the lithium-ion batteries. An air-flow-integrated thermal management system is designed in the present study to dissipate heat generation and uniformize the distribution of temperature in the lithium-ion batteries. The system contains of two types of air ducts with independent intake channels and fans. One is to cool the batteries through the regular channel, and the other minimizes the heat accumulations in the middle pack of batteries through jet cooling. A three-dimensional anisotropic heat transfer model is developed to describe the thermal behavior of the lithium-ion batteries with the integration of heat generation theory, and validated through both simulations and experiments. Moreover, the simulations and experiments show that the maximum temperature can be decreased to 33.1 °C through the new thermal management system in comparison with 42.3 °C through the traditional ones, and temperature uniformity of the lithium-ion battery packs is enhanced, significantly.

  13. Turbostar: an ICF reactor using both direct and thermal power conversion. Revision 1

    International Nuclear Information System (INIS)

    Pitts, J.H.

    1986-01-01

    Combining direct and thermal power conversion results in a 52% gross plant efficiency with DT fuel and 68% with advanced DD fuel. We maximize the fraction of fusion-yield energy converted to kinetic energy in a liquid-lithium blanket, and use this energy directly with turbine generators to produce electricity. We use the remainder of the energy to produce electricity in a standard Rankine thermal power conversion cycle

  14. Rapid method for direct identification of bacteria in urine and blood culture samples by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: intact cell vs. extraction method.

    Science.gov (United States)

    Ferreira, L; Sánchez-Juanes, F; Muñoz-Bellido, J L; González-Buitrago, J M

    2011-07-01

    Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a fast and reliable technology for the identification of microorganisms with proteomics approaches. Here, we compare an intact cell method and a protein extraction method before application on the MALDI plate for the direct identification of microorganisms in both urine and blood culture samples from clinical microbiology laboratories. The results show that the intact cell method provides excellent results for urine and is a good initial method for blood cultures. The extraction method complements the intact cell method, improving microorganism identification from blood culture. Thus, we consider that MALDI-TOF MS performed directly on urine and blood culture samples, with the protocols that we propose, is a suitable technique for microorganism identification, as compared with the routine methods used in the clinical microbiology laboratory. © 2010 The Authors. Clinical Microbiology and Infection © 2010 European Society of Clinical Microbiology and Infectious Diseases.

  15. Direct detection of the plant pathogens Burkholderia glumae, Burkholderia gladioli pv. gladioli, and Erwinia chrysanthemi pv. zeae in infected rice seedlings using matrix assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Kajiwara, Hideyuki

    2016-01-01

    The plant pathogens Burkholderia glumae, Burkholderia gladioli pv. gladioli, and Erwinia chrysanthemi pv. zeae were directly detected in extracts from infected rice seedlings by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This method did not require culturing of the pathogens on artificial medium. In the MALDI-TOF MS analysis, peaks originating from bacteria were found in extracts from infected rice seedlings. The spectral peaks showed significantly high scores, in spite of minor differences in spectra. The spectral peaks originating from host plant tissues did not affect this direct MALDI-TOF MS analysis for the rapid identification of plant pathogens. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Thermal tides and Martian dust storms: Direct evidence for coupling

    International Nuclear Information System (INIS)

    Leovy, C.B.; Zurek, R.W.

    1979-01-01

    Observations of surface pressure oscillations at the Viking 1 and Viking 2 lander sites on Mars indicate that the thermally driven global atmospheric tides were closely coupled to the dust content of the Martian atmosphere, especially during northern fall and winter, when two successive global dust storms occurred. The onset of each of these global storms was marked by substantial, nearly simultaneous increases in the dust opacity and in the range of the daily surface pressure variation observed at both lander sites. Although both the diurnal and semidiurnal tidal surface pressure components were amplified at Lander 1 during the onset of a global dust storm, the semidiurnal component was greatly enhanced in relation to the diurnal tide. Semidiurnal wind components were prominent at both lander sites during the height of the global dust storm. We have attempted to interpret these observations using simplified dynamical models. In particular, the semidiurnal wind component can be successfully related to the observed surface pressure variation using a simplified model of a semidiurnally forced Ekman boundary layer. On the other hand, a classical atmospheric tidal model shows that the preferential enhancement of the semidiurnal surface pressure oscillation at Lander 1 can be produced by a tidal heating distribution which places most of the heating (per unit mass) above 10-km altitude. Furthermore, when a dust storm expands to global scale, it does so rather quickly, and the total atmospheric heating at the peak of the dust storm can represent more than 50% of the available insolation. The Viking observations suggest that a number of mechanisms are important for the generation and decay of these episodic Martian global dust storms

  17. Deuterium desorption from tungsten using laser heating

    Directory of Open Access Journals (Sweden)

    J.H. Yu

    2017-08-01

    Full Text Available Retention and desorption of hydrogenic species need to be accurately modeled to predict the tritium inventory of next generation fusion devices, which is needed both for tritium fuel recovery and for tritium safety concerns. In this paper, experiments on thermal desorption of deuterium from intrinsic polycrystalline tungsten defects using laser heating are compared to TMAP-7 modeling. The samples during deuterium plasma exposure were at a temperature of 373K for this benchmark study with ion fluence of 0.7–1.0 ×1024Dm−2. Following plasma exposure, a fiber laser (λ= 1100nm heated the samples to peak surface temperatures ranging from ∼500 to 1400K with pulse widths from 10ms to 1s, and 1 to 10 pulses applied to each sample. The remaining deuterium retention was measured using temperature programmed desorption (TPD. Results show that > 95% of deuterium is desorbed when the peak surface temperature reached ∼950K for > 1s. TMAP-7 is used to predict deuterium desorption from tungsten for a range of surface temperatures and heating durations, and is compared to previous work on desorption from beryllium codeposits.

  18. Direct identification of bacteria from positive BacT/ALERT blood culture bottles using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry.

    Science.gov (United States)

    Mestas, Javier; Felsenstein, Susanna; Bard, Jennifer Dien

    2014-11-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is a fast and robust method for the identification of bacteria. In this study, we evaluate the performance of a laboratory-developed lysis method (LDT) for the rapid identification of bacteria from positive BacT/ALERT blood culture bottles. Of the 168 positive bottles tested, 159 were monomicrobial, the majority of which were Gram-positive organisms (61.0% versus 39.0%). Using a cut-off score of ≥1.7, 80.4% of the organisms were correctly identified to the species level, and the identification rate of Gram-negative organisms (90.3%) was found to be significantly greater than that of Gram-positive organisms (78.4%). The simplicity and cost-effectiveness of the LDT enable it to be fully integrated into the routine workflow of the clinical microbiology laboratory, allowing for rapid identification of Gram-positive and Gram-negative bacteria within an hour of blood culture positivity. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Direct numerical simulation of thermally-stratified turbulent boundary layer subjected to adverse pressure gradient

    International Nuclear Information System (INIS)

    Hattori, Hirofumi; Kono, Amane; Houra, Tomoya

    2016-01-01

    Highlights: • We study various thermally-stratified turbulent boundary layers having adverse pressure gradient (APG) by means of DNS. • The detailed turbulent statistics and structures in various thermally-stratified turbulent boundary layers having APG are discussed. • It is found that the friction coefficient and Stanton number decrease along the streamwise direction due to the effects of stable thermal stratification and APG, but those again increase due to the APG effect in the case of weak stable thermal stratification. • In the case of strong stable stratification with or without APG, the flow separation is observed in the downstream region. - Abstract: The objective of this study is to investigate and observe turbulent heat transfer structures and statistics in thermally-stratified turbulent boundary layers subjected to a non-equilibrium adverse pressure gradient (APG) by means of direct numerical simulation (DNS). DNSs are carried out under conditions of neutral, stable and unstable thermal stratifications with a non-equilibrium APG, in which DNS results reveal heat transfer characteristics of thermally-stratified non-equilibrium APG turbulent boundary layers. In cases of thermally-stratified turbulent boundary layers affected by APG, heat transfer performances increase in comparison with a turbulent boundary layer with neutral thermal stratification and zero pressure gradient (ZPG). Especially, it is found that the friction coefficient and Stanton number decrease along the streamwise direction due to the effects of stable thermal stratification and APG, but those again increase due to the APG effect in the case of weak stable thermal stratification (WSBL). Thus, the analysis for both the friction coefficient and Stanton number in the case of WSBL with/without APG is conducted using the FIK identity in order to investigate contributions from the transport equations, in which it is found that both Reynolds-shear-stress and the mean convection terms

  20. The sensitivity of direct identification from positive BacT/ALERT™ (bioMérieux) blood culture bottles by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is low.

    Science.gov (United States)

    Szabados, F; Michels, M; Kaase, M; Gatermann, S

    2011-02-01

    Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been presented as a novel method for the direct identification of bacteria from positive blood culture bottles. The rate of the MALDI TOF MS-based identification in the present study from positive BacT/ALERT (bioMérieux, Marcy l'Etoile, France) blood culture bottles was 30%, which is far below the previously reported sensitivities using the BACTEC (Becton Dickinson, Franklin Lakes, NJ, USA) system. We also found evidence that the Biotyper algorithm did not identify a second pathogen in cases of positive BacT/ALERT blood culture bottles containing two different species. © 2010 The Authors. Journal Compilation © 2010 European Society of Clinical Microbiology and Infectious Diseases.

  1. Desorption of Lipases Immobilized on Octyl-Agarose Beads and Coated with Ionic Polymers after Thermal Inactivation. Stronger Adsorption of Polymers/Unfolded Protein Composites

    Directory of Open Access Journals (Sweden)

    Jose J. Virgen-Ortíz

    2017-01-01

    Full Text Available Lipases from Candida antarctica (isoform B and Rhizomucor miehei (CALB and RML have been immobilized on octyl-agarose (OC and further coated with polyethylenimine (PEI and dextran sulfate (DS. The enzymes just immobilized on OC supports could be easily released from the support using 2% SDS at pH 7, both intact or after thermal inactivation (in fact, after inactivation most enzyme molecules were already desorbed. The coating with PEI and DS greatly reduced the enzyme release during thermal inactivation and improved enzyme stability. However, using OC-CALB/RML-PEI-DS, the full release of the immobilized enzyme to reuse the support required more drastic conditions: a pH value of 3, a buffer concentration over 2 M, and temperatures above 45 °C. However, even these conditions were not able to fully release the thermally inactivated enzyme molecules from the support, being necessary to increase the buffer concentration to 4 M sodium phosphate and decrease the pH to 2.5. The formation of unfolded protein/polymers composites seems to be responsible for this strong interaction between the octyl and some anionic groups of OC supports. The support could be reused five cycles using these conditions with similar loading capacity of the support and stability of the immobilized enzyme.

  2. Insight to the Thermal Decomposition and Hydrogen Desorption Behaviors of NaNH2-NaBH4 Hydrogen Storage Composite.

    Science.gov (United States)

    Pei, Ziwei; Bai, Ying; Wang, Yue; Wu, Feng; Wu, Chuan

    2017-09-20

    The lightweight compound material NaNH 2 -NaBH 4 is regarded as a promising hydrogen storage composite due to the high hydrogen density. Mechanical ball milling was employed to synthesize the composite NaNH 2 -NaBH 4 (2/1 molar ratio), and the samples were investigated utilizing thermogravimetric-differential thermal analysis-mass spectroscopy (TG-DTA-MS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. The full-spectrum test (range of the ratio of mass to charge: 0-200) shows that the released gaseous species contain H 2 , NH 3 , B 2 H 6 , and N 2 in the heating process from room temperature to 400 °C, and possibly the impurity gas B 6 H 12 also exists. The TG/DTA analyses show that the composite NaNH 2 -NaBH 4 (2/1 molar ratio) is conductive to generate hydrogen so that the dehydrogenation process can be finished before 400 °C. Moreover, the thermal decomposition process from 200 to 400 °C involves two-step dehydrogenation reactions: (1) Na 3 (NH 2 ) 2 BH 4 hydride decomposes into Na 3 BN 2 and H 2 (200-350 °C); (2) remaining Na 3 (NH 2 ) 2 BH 4 reacts with NaBH 4 and Na 3 BN 2 , generating Na, BN, NH 3 , N 2 , and H 2 (350-400 °C). The better mechanism understanding of the thermal decomposition pathway lays a foundation for tailoring the hydrogen storage performance of the composite complex hydrides system.

  3. Direct observation of free-exciton thermalization in quantum-well structures

    DEFF Research Database (Denmark)

    Umlauff, M.; Hoffmann, J.; Kalt, H.

    1998-01-01

    We report on a direct observation of free-exciton thermalization in quantum-well structures. A narrow energy distribution of free 1s excitons is created in ZnSe-based quantum wells by emission of one LO phonon after optical excitation of the continuum stales with picosecond laser pulses. The subs......We report on a direct observation of free-exciton thermalization in quantum-well structures. A narrow energy distribution of free 1s excitons is created in ZnSe-based quantum wells by emission of one LO phonon after optical excitation of the continuum stales with picosecond laser pulses...

  4. Direct analysis and identification of pathogenic Lichtheimia species by matrix-assisted laser desorption ionization-time of flight analyzer-mediated mass spectrometry.

    Science.gov (United States)

    Schrödl, Wieland; Heydel, Tilo; Schwartze, Volker U; Hoffmann, Kerstin; Grosse-Herrenthey, Anke; Walther, Grit; Alastruey-Izquierdo, Ana; Rodriguez-Tudela, Juan Luis; Olias, Philipp; Jacobsen, Ilse D; de Hoog, G Sybren; Voigt, Kerstin

    2012-02-01

    Zygomycetes of the order Mucorales can cause life-threatening infections in humans. These mucormycoses are emerging and associated with a rapid tissue destruction and high mortality. The resistance of Mucorales to antimycotic substances varies between and within clinically important genera such as Mucor, Rhizopus, and Lichtheimia. Thus, an accurate diagnosis before onset of antimycotic therapy is recommended. Matrix-assisted laser desorption ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) is a potentially powerful tool to rapidly identify infectious agents on the species level. We investigated the potential of MALDI-TOF MS to differentiate Lichtheimia species, one of the most important agents of mucormycoses. Using the Bruker Daltonics FlexAnalysis (version 3.0) software package, a spectral database library with m/z ratios of 2,000 to 20,000 Da was created for 19 type and reference strains of clinically relevant Zygomycetes of the order Mucorales (12 species in 7 genera). The database was tested for accuracy by use of 34 clinical and environmental isolates of Lichtheimia comprising a total of five species. Our data demonstrate that MALDI-TOF MS can be used to clearly discriminate Lichtheimia species from other pathogenic species of the Mucorales. Furthermore, the method is suitable to discriminate species within the genus. The reliability and robustness of the MALDI-TOF-based identification are evidenced by high score values (above 2.3) for the designation to a certain species and by moderate score values (below 2.0) for the discrimination between clinically relevant (Lichtheimia corymbifera, L. ramosa, and L. ornata) and irrelevant (L. hyalospora and L. sphaerocystis) species. In total, all 34 strains were unequivocally identified by MALDI-TOF MS with score values of >1.8 down to the generic level, 32 out of 34 of the Lichtheimia isolates (except CNM-CM 5399 and FSU 10566) were identified accurately with score values of >2 (probable species

  5. Direct Analysis and Identification of Pathogenic Lichtheimia Species by Matrix-Assisted Laser Desorption Ionization–Time of Flight Analyzer-Mediated Mass Spectrometry

    Science.gov (United States)

    Schrödl, Wieland; Heydel, Tilo; Schwartze, Volker U.; Hoffmann, Kerstin; Große-Herrenthey, Anke; Walther, Grit; Alastruey-Izquierdo, Ana; Rodriguez-Tudela, Juan Luis; Olias, Philipp; Jacobsen, Ilse D.; de Hoog, G. Sybren

    2012-01-01

    Zygomycetes of the order Mucorales can cause life-threatening infections in humans. These mucormycoses are emerging and associated with a rapid tissue destruction and high mortality. The resistance of Mucorales to antimycotic substances varies between and within clinically important genera such as Mucor, Rhizopus, and Lichtheimia. Thus, an accurate diagnosis before onset of antimycotic therapy is recommended. Matrix-assisted laser desorption ionization (MALDI)–time of flight (TOF) mass spectrometry (MS) is a potentially powerful tool to rapidly identify infectious agents on the species level. We investigated the potential of MALDI-TOF MS to differentiate Lichtheimia species, one of the most important agents of mucormycoses. Using the Bruker Daltonics FlexAnalysis (version 3.0) software package, a spectral database library with m/z ratios of 2,000 to 20,000 Da was created for 19 type and reference strains of clinically relevant Zygomycetes of the order Mucorales (12 species in 7 genera). The database was tested for accuracy by use of 34 clinical and environmental isolates of Lichtheimia comprising a total of five species. Our data demonstrate that MALDI-TOF MS can be used to clearly discriminate Lichtheimia species from other pathogenic species of the Mucorales. Furthermore, the method is suitable to discriminate species within the genus. The reliability and robustness of the MALDI-TOF-based identification are evidenced by high score values (above 2.3) for the designation to a certain species and by moderate score values (below 2.0) for the discrimination between clinically relevant (Lichtheimia corymbifera, L. ramosa, and L. ornata) and irrelevant (L. hyalospora and L. sphaerocystis) species. In total, all 34 strains were unequivocally identified by MALDI-TOF MS with score values of >1.8 down to the generic level, 32 out of 34 of the Lichtheimia isolates (except CNM-CM 5399 and FSU 10566) were identified accurately with score values of >2 (probable species

  6. Detailed partial load investigation of a thermal energy storage concept for solar thermal power plants with direct steam generation

    Science.gov (United States)

    Seitz, M.; Hübner, S.; Johnson, M.

    2016-05-01

    Direct steam generation enables the implementation of a higher steam temperature for parabolic trough concentrated solar power plants. This leads to much better cycle efficiencies and lower electricity generating costs. For a flexible and more economic operation of such a power plant, it is necessary to develop thermal energy storage systems for the extension of the production time of the power plant. In the case of steam as the heat transfer fluid, it is important to use a storage material that uses latent heat for the storage process. This leads to a minimum of exergy losses during the storage process. In the case of a concentrating solar power plant, superheated steam is needed during the discharging process. This steam cannot be superheated by the latent heat storage system. Therefore, a sensible molten salt storage system is used for this task. In contrast to the state-of-the-art thermal energy storages within the concentrating solar power area of application, a storage system for a direct steam generation plant consists of a latent and a sensible storage part. Thus far, no partial load behaviors of sensible and latent heat storage systems have been analyzed in detail. In this work, an optimized fin structure was developed in order to minimize the costs of the latent heat storage. A complete system simulation of the power plant process, including the solar field, power block and sensible and latent heat energy storage calculates the interaction between the solar field, the power block and the thermal energy storage system.

  7. Analysis of volatile organic compounds released from the decay of surrogate human models simulating victims of collapsed buildings by thermal desorption-comprehensive two-dimensional gas chromatography-time of flight mass spectrometry.

    Science.gov (United States)

    Agapiou, A; Zorba, E; Mikedi, K; McGregor, L; Spiliopoulou, C; Statheropoulos, M

    2015-07-09

    Field experiments were devised to mimic the entrapment conditions under the rubble of collapsed buildings aiming to investigate the evolution of volatile organic compounds (VOCs) during the early dead body decomposition stage. Three pig carcasses were placed inside concrete tunnels of a search and rescue (SAR) operational field terrain for simulating the entrapment environment after a building collapse. The experimental campaign employed both laboratory and on-site analytical methods running in parallel. The current work focuses only on the results of the laboratory method using thermal desorption coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (TD-GC×GC-TOF MS). The flow-modulated TD-GC×GC-TOF MS provided enhanced separation of the VOC profile and served as a reference method for the evaluation of the on-site analytical methods in the current experimental campaign. Bespoke software was used to deconvolve the VOC profile to extract as much information as possible into peak lists. In total, 288 unique VOCs were identified (i.e., not found in blank samples). The majority were aliphatics (172), aromatics (25) and nitrogen compounds (19), followed by ketones (17), esters (13), alcohols (12), aldehydes (11), sulfur (9), miscellaneous (8) and acid compounds (2). The TD-GC×GC-TOF MS proved to be a sensitive and powerful system for resolving the chemical puzzle of above-ground "scent of death". Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Direct measurement of thermal conductivity in solid iron at planetary core conditions.

    Science.gov (United States)

    Konôpková, Zuzana; McWilliams, R Stewart; Gómez-Pérez, Natalia; Goncharov, Alexander F

    2016-06-02

    The conduction of heat through minerals and melts at extreme pressures and temperatures is of central importance to the evolution and dynamics of planets. In the cooling Earth's core, the thermal conductivity of iron alloys defines the adiabatic heat flux and therefore the thermal and compositional energy available to support the production of Earth's magnetic field via dynamo action. Attempts to describe thermal transport in Earth's core have been problematic, with predictions of high thermal conductivity at odds with traditional geophysical models and direct evidence for a primordial magnetic field in the rock record. Measurements of core heat transport are needed to resolve this difference. Here we present direct measurements of the thermal conductivity of solid iron at pressure and temperature conditions relevant to the cores of Mercury-sized to Earth-sized planets, using a dynamically laser-heated diamond-anvil cell. Our measurements place the thermal conductivity of Earth's core near the low end of previous estimates, at 18-44 watts per metre per kelvin. The result is in agreement with palaeomagnetic measurements indicating that Earth's geodynamo has persisted since the beginning of Earth's history, and allows for a solid inner core as old as the dynamo.

  9. Ceramic thermal wind sensor based on advanced direct chip attaching package

    International Nuclear Information System (INIS)

    Zhou Lin; Qin Ming; Chen Shengqi; Chen Bei

    2014-01-01

    An advanced direct chip attaching packaged two-dimensional ceramic thermal wind sensor is studied. The thermal wind sensor chip is fabricated by metal lift-off processes on the ceramic substrate. An advanced direct chip attaching (DCA) packaging is adopted and this new packaged method simplifies the processes of packaging further. Simulations of the advanced DCA packaged sensor based on computational fluid dynamics (CFD) model show the sensor can detect wind speed and direction effectively. The wind tunnel testing results show the advanced DCA packaged sensor can detect the wind direction from 0° to 360° and wind speed from 0 to 20 m/s with the error less than 0.5 m/s. The nonlinear fitting based least square method in Matlab is used to analyze the performance of the sensor. (semiconductor devices)

  10. Polydimethylsiloxane rod extraction, a novel technique for the determination of organic micropollutants in water samples by thermal desorption-capillary gas chromatography-mass spectrometry.

    Science.gov (United States)

    Montero, L; Popp, P; Paschke, A; Pawliszyn, J

    2004-01-30

    A novel, simple and inexpensive approach to absorptive extraction of organic compounds from environmental samples is presented. It consists of a polydimethylsiloxane rod used as an extraction media, enriched with analytes during shaking, then thermally desorbed and analyzed by GC-MS. Its performance was illustrated and evaluated for the enrichment of sub- to ng/l of selected chlorinated compounds (chlorobenzenes and polychlorinated biphenyls) in water samples. The new approach was compared to the stir bar sorptive extraction performance. A natural ground water sample from Bitterfeld, Germany, was also extracted using both methods, showing good agreement. The proposed approach presented good linearity, high sensitivity, good blank levels and recoveries comparable to stir bars, together with advantages such as simplicity, lower cost and higher feasibility.

  11. The effect of linear imperfection in [001] direction on the thermal properties of silver crystal

    Directory of Open Access Journals (Sweden)

    J Davoodi

    2013-09-01

    Full Text Available  The aim of this investigation was to calculate the thermal properties of silver crystal in the presence of linear imperfection. The simulations were performed by molecular dynamics simulation technique in NPT as well as NVT ensemble based on quantum Sutton-Chen many body potential. The thermal properties including cohesive energy, melting temperature, isobaric heat capacity and thermal expansion of imperfect silver crystal were calculated and compared to those of the perfect crystal. Moreover, the quantities such as radial distribution function, order parameter and lindemann index were calculated in order to obtain information on crystal structure and disorder in atoms. All calculations were done both with liner imperfection in [001] direction and without imperfection at different temperature. The simulation results show that cohesive energy, linear thermal expansion coefficient increase and melting temperature, latent heat of fusion decrease with increasing linear imperfection. Also, the results show that linear imperfection has no effect on the heat capacity.

  12. THERMAL AND DIELECTRIC PROPERTIES OF PINE WOOD IN THE TRANSVERSE DIRECTION

    Directory of Open Access Journals (Sweden)

    Hamiyet Şahin Kol

    2009-11-01

    Full Text Available In this paper, the thermal conductivity and dielectric parameters for pine [Pinus sylvestris (L.] woods were determined in transverse directions for moisture conditions from oven-dry to 22 percent at a room temperature of 22 to 24 °C. Results indicate that the behaviors of thermal conductivity and dielectric parameters with moisture content and structural directions were similar. In general, the properties increased within the range studied with increasing moisture content. The radial values were similar to tangential values for both thermal conductivity and dielectric properties. The data presented here should be useful in most design problems where pine wood is subjected to microwave electric fields and heat changes.

  13. Colour-the-INSight : Combining a direct view rifle sight with fused intensified and thermal imagery

    NARCIS (Netherlands)

    Hogervorst, M.A.; Jansen, C.; Toet, A.; Bijl, P.; Bakker, P.J.; Hiddema, A.C.; Vliet, S.F. van

    2012-01-01

    We present the design and evaluation of a new demonstrator rifle sight viewing system containing direct view, red aim point and fusion of an (uncooled, LWIR) thermal sensor with a digital image intensifier. Our goal is to create a system that performs well under a wide variety of (weather)

  14. Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review

    Directory of Open Access Journals (Sweden)

    Wisut Chamsa-ard

    2017-05-01

    Full Text Available The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

  15. Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review.

    Science.gov (United States)

    Chamsa-Ard, Wisut; Brundavanam, Sridevi; Fung, Chun Che; Fawcett, Derek; Poinern, Gerrard

    2017-05-31

    The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

  16. Identification of blood culture isolates directly from positive blood cultures by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry and a commercial extraction system: analysis of performance, cost, and turnaround time.

    Science.gov (United States)

    Lagacé-Wiens, Philippe R S; Adam, Heather J; Karlowsky, James A; Nichol, Kimberly A; Pang, Paulette F; Guenther, Jodi; Webb, Amanda A; Miller, Crystal; Alfa, Michelle J

    2012-10-01

    Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry represents a revolution in the rapid identification of bacterial and fungal pathogens in the clinical microbiology laboratory. Recently, MALDI-TOF has been applied directly to positive blood culture bottles for the rapid identification of pathogens, leading to reductions in turnaround time and potentially beneficial patient impacts. The development of a commercially available extraction kit (Bruker Sepsityper) for use with the Bruker MALDI BioTyper has facilitated the processing required for identification of pathogens directly from positive from blood cultures. We report the results of an evaluation of the accuracy, cost, and turnaround time of this method for 61 positive monomicrobial and 2 polymicrobial cultures representing 26 species. The Bruker MALDI BioTyper with the Sepsityper gave a valid (score, >1.7) identification for 85.2% of positive blood cultures with no misidentifications. The mean reduction in turnaround time to identification was 34.3 h (P MALDI-TOF was used for all blood cultures and 26.5 h in a more practical setting where conventional identification or identification from subcultures was required for isolates that could not be directly identified by MALDI-TOF. Implementation of a MALDI-TOF-based identification system for direct identification of pathogens from blood cultures is expected to be associated with a marginal increase in operating costs for most laboratories. However, the use of MALDI-TOF for direct identification is accurate and should result in reduced turnaround time to identification.

  17. Performance evaluation of four directional emissivity analytical models with thermal SAIL model and airborne images.

    Science.gov (United States)

    Ren, Huazhong; Liu, Rongyuan; Yan, Guangjian; Li, Zhao-Liang; Qin, Qiming; Liu, Qiang; Nerry, Françoise

    2015-04-06

    Land surface emissivity is a crucial parameter in the surface status monitoring. This study aims at the evaluation of four directional emissivity models, including two bi-directional reflectance distribution function (BRDF) models and two gap-frequency-based models. Results showed that the kernel-driven BRDF model could well represent directional emissivity with an error less than 0.002, and was consequently used to retrieve emissivity with an accuracy of about 0.012 from an airborne multi-angular thermal infrared data set. Furthermore, we updated the cavity effect factor relating to multiple scattering inside canopy, which improved the performance of the gap-frequency-based models.

  18. Direct identification of microorganisms from positive blood cultures using the lysis-filtration technique and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): a multicentre study.

    Science.gov (United States)

    Farina, Claudio; Arena, Fabio; Casprini, Patrizia; Cichero, Paola; Clementi, Massimo; Cosentino, Marina; Degl'Innocenti, Roberto; Giani, Tommaso; Luzzaro, Francesco; Mattei, Romano; Mauri, Carola; Nardone, Maria; Rossolini, Gian Maria; Serna Ortega, Paula Andrea; Vailati, Francesca

    2015-04-01

    Microbial identification from blood cultures is essential to institute optimal antibiotic therapy and improve survival possibilities. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied to identify bacteria and yeasts from positive blood cultures broths. The aim of this multicentre study was to evaluate the reliability of the lysis-filtration technique associated with MALDI-TOF MS to directly identify microorganisms from 765 positive blood cultures collected in six Italian hospitals. Overall, 675/765 (78.1%) blood isolates were correctly identified at the species level, with significant differences between Gram-negative and Gram-positive bacteria (92.6%, and 69.8%, respectively). Some difficulties arise in identifying Streptococcus pneumoniae, Staphylococcus aureus, yeasts and anaerobes. The lysis-filtration protocol is a suitable procedure in terms of performance in identifying microorganisms, but it is quite expensive and technically time-consuming since the time of filtration is not regular for all the samples. The application of the MALDI-TOF MS technique to the direct microbial identification from positive blood cultures is a very promising approach, even if more experience must be gained to minimize errors and costs.

  19. Direct identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS from positive blood culture bottles: An opportunity to customize growth conditions for fastidious organisms causing bloodstream infections

    Directory of Open Access Journals (Sweden)

    Megha Sharma

    2017-01-01

    Full Text Available Culture-negative bacteraemia has been an enigmatic entity with respect to its aetiological agents. In an attempt to actively identify those positive blood cultures that escape isolation and detection on routine workflow, an additional step of MALDI-TOF MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry based detection was carried out directly from the flagged blood culture bottles. Blood samples from 200 blood culture bottles that beeped positive with automated (BACTEC system and showed no growth of organism on routine culture media, were subjected to analysis by MALDI-TOF MS. Forty seven of the 200 (23.5% bacterial aetiology could be established by bottle-based method. Based on these results, growth on culture medium could be achieved for the isolates by providing special growth conditions to the fastidious organisms. Direct identification by MALDI-TOF MS from BACTEC-positive bottles provided an opportunity to isolate those fastidious organisms that failed to grow on routine culture medium by providing them with necessary alterations in growth environment.

  20. Direct identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) from positive blood culture bottles: An opportunity to customize growth conditions for fastidious organisms causing bloodstream infections.

    Science.gov (United States)

    Sharma, Megha; Gautam, Vikas; Mahajan, Monika; Rana, Sudesh; Majumdar, Manasi; Ray, Pallab

    2017-10-01

    Culture-negative bacteraemia has been an enigmatic entity with respect to its aetiological agents. In an attempt to actively identify those positive blood cultures that escape isolation and detection on routine workflow, an additional step of MALDI-TOF MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry) based detection was carried out directly from the flagged blood culture bottles. Blood samples from 200 blood culture bottles that beeped positive with automated (BACTEC) system and showed no growth of organism on routine culture media, were subjected to analysis by MALDI-TOF MS. Forty seven of the 200 (23.5%) bacterial aetiology could be established by bottle-based method. Based on these results, growth on culture medium could be achieved for the isolates by providing special growth conditions to the fastidious organisms. Direct identification by MALDI-TOF MS from BACTEC-positive bottles provided an opportunity to isolate those fastidious organisms that failed to grow on routine culture medium by providing them with necessary alterations in growth environment.

  1. Laser-induced desorption of organic molecules from front- and back-irradiated metal foils

    International Nuclear Information System (INIS)

    Zinovev, Alexander V.; Veryovkin, Igor V.; Pellin, Michael J.

    2009-01-01

    Laser-Induced Acoustic Desorption (LIAD) from thin metal foils is a promising technique for gentle and efficient volatilization of intact organic molecules from surfaces of solid substrates. Using the Single Photon Ionization (SPI) method combined with time-of-flight mass-spectrometry (TOF MS), desorbed flux in LIAD was examined and compared to that from direct laser desorption (LD). Molecules of various organic dyes were used in experiments. Translational velocities of the desorbed intact molecules did not depend on the desorbing laser intensity, which implies the presence of more sophisticated mechanism of energy transfer than the direct mechanical or thermal coupling between the laser pulse and the adsorbed molecules. The results of our experiments indicate that the LIAD phenomenon cannot be described in terms of a simple mechanical shake-off nor the direct laser desorption. Rather, they suggest that multi-step energy transfer processes are involved. Possible qualitative mechanism of LIAD that are based on formation of non-equilibrium energy states in the adsorbate-substrate system are proposed and discussed.

  2. Determination of delta9-tetrahydrocannabinol in indoor air as an indicator of marijuana cigarette smoking using adsorbent sampling and in-injector thermal desorption gas chromatography-mass spectrometry.

    Science.gov (United States)

    Chou, Su-Lien; Ling, Yong-Chien; Yang, Mo-Hsiung; Pai, Chung-Yen

    2007-08-13

    The marijuana leaves are usually mixed with tobaccos and smoked at amusement places in Taiwan. Recently, for investigation-legal purposes, the police asked if we can identify the marijuana smoke in a KTV stateroom (a private room at the entertainment spot for singing, smoking, alcohol drinking, etc.) without marijuana residues. A personal air-sampler pump fitted with the GC liner-tube packed with Tenax-TA adsorbent was used for air sampling. The GC-adsorbent tube was placed in the GC injector port and desorbed directly, followed by GC-MS analysis for the determination of delta9-tetrahydrocannabinol (delta9-THC) in indoor air. The average desorption efficiency and limit of detection for delta9-THC were 89% and 0.1 microg m(-3), respectively, approximately needing 1.09 mg of marijuana leaves smoked in an unventilated closed room (3.0 m x 2.4 m x 2.7 m) to reach this level. The mean delta9-THC contained in the 15 marijuana plants seized from diverse locations was measured to be 0.32%. The delta9-THC in room air can be successfully identified from mock marijuana cigarettes, mixtures of marijuana and tobacco, and an actual case. The characteristic delta9-THC peak in chromatogram can serve as the indicator of marijuana. Positive result suggests marijuana smoking at the specific scene in the recent past, facilitating the formulation of further investigation.

  3. The colour of thermal noise in classical Brownian motion: a feasibility study of direct experimental observation

    International Nuclear Information System (INIS)

    Berg-Soerensen, Kirstine; Flyvbjerg, Henrik

    2005-01-01

    One hundred years after Einstein modelled Brownian motion, a central aspect of this motion in incompressible fluids has not been verified experimentally: the thermal noise that drives the Brownian particle, is not white, as in Einstein's simple theory. It is slightly coloured, due to hydrodynamics and the fluctuation-dissipation theorem. This theoretical result from the 1970s was prompted by computer simulation results in apparent violation of Einstein's theory. We discuss how a direct experimental observation of this colour might be carried out by using optical tweezers to separate the thermal noise from the particle's dynamic response to it. Since the thermal noise is almost white, very good statistics is necessary to resolve its colour. That requires stable equipment and long recording times, possibly making this experiment one for the future only. We give results for experimental requirements and for stochastic errors as functions of experimental window and measurement time, and discuss some potential sources of systematic errors

  4. System and method of providing quick thermal comfort with reduced energy by using directed spot conditioning

    Science.gov (United States)

    Wang, Mingyu; Kadle, Prasad S.; Ghosh, Debashis; Zima, Mark J.; Wolfe, IV, Edward; Craig, Timothy D

    2016-10-04

    A heating, ventilation, and air conditioning (HVAC) system and a method of controlling a HVAC system that is configured to provide a perceived comfortable ambient environment to an occupant seated in a vehicle cabin. The system includes a nozzle configured to direct an air stream from the HVAC system to the location of a thermally sensitive portion of the body of the occupant. The system also includes a controller configured to determine an air stream temperature and an air stream flow rate necessary to establish the desired heat supply rate for the sensitive portion and provide a comfortable thermal environment by thermally isolating the occupant from the ambient vehicle cabin temperature. The system may include a sensor to determine the location of the sensitive portion. The nozzle may include a thermoelectric device to heat or cool the air stream.

  5. Out-of-plane platforms with bi-directional thermal bimorph actuation for transducer applications

    KAUST Repository

    Conchouso Gonzalez, David

    2015-04-01

    This paper reports on the Buckled Cantilever Platform (BCP) that allows the manipulation of the out of plane structures through the adjustment of the pitch angle using thermal bimorph micro-Actuators. Due to the micro-fabrication process used, the bimorph actuators can be designed to move in both: Counter Clockwise (CCW) and Clockwise (CW) directions with a resolution of up to 110 μm/V, with smallest step in the range of nanometers. Thermal and electrical characterization of the thermal bimorph actuators showed low influence in the platforms temperature and low power consumption (< 35μW) mainly due to the natural isolation of the structure. Tip displacements larger than 500μm were achieved. The precise angle adjustment achieved through these mechanisms makes them optimal for a range of different MEMS applications, like optical benches and low frequency sweeping sensors and antennas. © 2015 IEEE.

  6. Evaluation of laser diode thermal desorption (LDTD) coupled with tandem mass spectrometry (MS/MS) for support of in vitro drug discovery assays: increasing scope, robustness and throughput of the LDTD technique for use with chemically diverse compound libraries.

    Science.gov (United States)

    Beattie, Iain; Smith, Aaron; Weston, Daniel J; White, Peter; Szwandt, Simon; Sealey, Laura

    2012-02-05

    Within the drug discovery environment, the key process in optimising the chemistry of a structural series toward a potential drug candidate is the design, make and test cycle, in which the primary screens consist of a number of in vitro assays, including metabolic stability, cytochrome P450 inhibition, and time-dependent inhibition assays. These assays are often carried out using multiple drug compounds with chemically diverse structural features, often in a 96 well-plate format for maximum time-efficiency, and are supported using rapid liquid chromatographic (LC) sample introduction with a tandem mass spectrometry (MS/MS) selected reaction monitoring (SRM) endpoint, taking around 6.5 h per plate. To provide a faster time-to-decision at this critical point, there exists a requirement for higher sample throughput and a robust, well-characterized analytical alternative. This paper presents a detailed evaluation of laser diode thermal desorption (LDTD), a relatively new ambient sample ionization technique, for compound screening assays. By systematic modification of typical LDTD instrumentation and workflow, and providing deeper understanding around overcoming a number of key issues, this work establishes LDTD as a practical, rapid alternative to conventional LC-MS/MS in drug discovery, without need for extensive sample preparation or expensive, scope-limiting internal standards. Analysis of both the five and three cytochrome P450 competitive inhibition assay samples by LDTD gave improved sample throughput (0.75 h per plate) and provided comparable data quality as the IC₅₀ values obtained were within 3 fold of those calculated from the LC-MS/MS data. Additionally when applied generically to a chemically diverse library of over 250 proprietary compounds from the AstraZeneca design, make and test cycle, LDTD demonstrated a success rate of 98%. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Direct numerical simulation of stable and unstable turbulent thermal boundary layers

    International Nuclear Information System (INIS)

    Hattori, Hirofumi; Houra, Tomoya; Nagano, Yasutaka

    2007-01-01

    This paper presents direct numerical simulations (DNS) of stable and unstable turbulent thermal boundary layers. Since a buoyancy-affected boundary layer is often encountered in an urban environmental space where stable and unstable stratifications exist, exploring a buoyancy-affected boundary layer is very important to know the transport phenomena of the flow in an urban space. Although actual observation may qualitatively provide the characteristics of these flows, the relevant quantitative turbulent quantities are very difficult to measure. Thus, in order to quantitatively investigate a buoyancy-affected boundary layer in detail, we have here carried out for the first time time- and space-developing DNS of slightly stable and unstable turbulent thermal boundary layers. The DNS results show the quantitative turbulent statistics and structures of stable and unstable thermal boundary layers, in which the characteristic transport phenomena of thermally stratified boundary layers are demonstrated by indicating the budgets of turbulent shear stress and turbulent heat flux. Even though the input of buoyant force is not large, the influence of buoyancy is clearly revealed in both stable and unstable turbulent boundary layers. In particular, it is found that both stable and unstable thermal stratifications caused by the weak buoyant force remarkably alter the structure of near-wall turbulence

  8. Temperature-modulated direct thermoelectric gas sensors: thermal modeling and results for fast hydrocarbon sensors

    International Nuclear Information System (INIS)

    Rettig, Frank; Moos, Ralf

    2009-01-01

    Direct thermoelectric gas sensors are a promising alternative to conductometric gas sensors. For accurate results, a temperature modulation technique in combination with a regression analysis is advantageous. However, the thermal time constant of screen-printed sensors is quite large. As a result, up to now the temperature modulation frequency (20 mHz) has been too low and the corresponding principle-related response time (50 s) has been too high for many applications. With a special design, respecting the physical properties of thermal waves and the use of signal processing similar to a lock-in-amplifier, it is possible to achieve response times of about 1 s. As a result, direct thermoelectric gas sensors with SnO 2 as a gas-sensitive material respond fast and are reproducible to the propane concentration in the ambient atmosphere. Due to the path-independent behavior of the thermovoltage and the temperature, the measured thermopower of two sensors is almost identical

  9. Direct Identification and Antimicrobial Susceptibility Testing of Bacteria From Positive Blood Culture Bottles by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry and the Vitek 2 System.

    Science.gov (United States)

    Jo, Sung Jin; Park, Kang Gyun; Han, Kyungja; Park, Dong Jin; Park, Yeon-Joon

    2016-03-01

    We evaluated the reliability and accuracy of the combined use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) bacterial identification and Vitek 2 antimicrobial susceptibility testing (AST) for bacteria from positive blood culture bottles. Direct identification and AST were performed in parallel to the standard methods in monomicrobial positive blood culture bottles. In total, 254 isolates grown on aerobic and/or anaerobic bottles were identified with MALDI-TOF Vitek MS (bioMérieux, France), and 1,978 microorganism/antimicrobial agent combinations were assessed. For isolates from anaerobic bottles, an aliquot of the culture broth was centrifuged, washed, and filtered through a nylon mesh. For isolates from aerobic/pediatric bottles, a lysis step using 9.26% ammonium chloride solution and 2% saponin solution was included. The overall correct identification rate was 81.8% (208/254) and that for gram-positive/gram-negative isolates was 73.9%/92.6%, respectively, and it was 81.8%, 87.6%, and 57.9% for isolates from aerobic, anaerobic, and pediatric bottles, respectively. Identification was not possible in 45 cases, and most of these isolates were streptococci (N=14) and coagulase-negative staphylococci (N=11). Misidentification occurred only in one case. Compared with standard methods, direct AST showed 97.9% (1,936/1,978) agreement with very major error of 0.25%, major error of 0.05%, and minor error of 1.8%. This simple and cost-effective sample preparation method gives reliable results for the direct identification and AST of bacteria. For the identification of streptococci and coagulase-negative staphylococci, the method should be further improved.

  10. Direct bacterial identification from positive blood cultures using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry: A systematic review and meta-analysis.

    Science.gov (United States)

    Ruiz-Aragón, Jesús; Ballestero-Téllez, Mónica; Gutiérrez-Gutiérrez, Belén; de Cueto, Marina; Rodríguez-Baño, Jesús; Pascual, Álvaro

    2017-10-27

    The rapid identification of bacteraemia-causing pathogens could assist clinicians in the timely prescription of targeted therapy, thereby reducing the morbidity and mortality of this infection. In recent years, numerous techniques that rapidly and directly identify positive blood cultures have been marketed, with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) being one of the most commonly used. The aim of this systematic review and meta-analysis was to evaluate the accuracy of MALDI-TOF (Bruker ® ) for the direct identification of positive blood culture bottles. A meta-analysis was performed to summarize the results of the 32 studies evaluated. The overall quality of the studies was moderate. For Gram-positive bacteria, overall rates of correct identification of the species ranged from 0.17 to 0.98, with a cumulative rate (random-effects model) of 0.72 (95% CI: 0.64-0.80). For Gram-negative bacteria, correct identification rates ranged from 0.66 to 1.00, with a cumulative effect of 0.92 (95% CI: 0.88-0.95). For Enterobacteriaceae, the rate was 0.96 (95% CI: 0.94-0.97). MALDI-TOF mass spectrometry shows high accuracy for the correct identification of Gram-negative bacteria, particularly Enterobacteriaceae, directly from positive blood culture bottles, and moderate accuracy for the identification of Gram-positive bacteria (low for some species). Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  11. Hybrid indirect/direct contactor for thermal management of counter-current processes

    Science.gov (United States)

    Hornbostel, Marc D.; Krishnan, Gopala N.; Sanjurjo, Angel

    2018-03-20

    The invention relates to contactors suitable for use, for example, in manufacturing and chemical refinement processes. In an aspect is a hybrid indirect/direct contactor for thermal management of counter-current processes, the contactor comprising a vertical reactor column, an array of interconnected heat transfer tubes within the reactor column, and a plurality of stream path diverters, wherein the tubes and diverters are configured to block all straight-line paths from the top to bottom ends of the reactor column.

  12. Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry System for Identification of Aspergillus Species Directly from Growth on Solid Agar Media

    Directory of Open Access Journals (Sweden)

    Ying Li

    2017-06-01

    Full Text Available We evaluated the accuracy of the Bruker Biotyper matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS system at identifying clinical isolates of Aspergillus species that were grown on agar media. A total of 381 non-duplicate Aspergillus isolates representing 21 different Aspergillus species identified by molecular analysis were included in this study. The Bruker Biotyper MALDI-TOF MS system was able to identify 30.2% (115/381 of the isolates to the species level (score values of ≥2.000 and 49.3% to the genus level (score values of 1.700–1.999. When the identification cutoff value was lowered from ≥2.000 to ≥1.700, the species-level identification rate increased to 79.5% with a slight rise of false identification from 2.6 to 5.0%. From another aspect, a correct species-level identification rate of 89% could be reached by the Bruker Biotyper MALDI-TOF MS system regardless of the score values obtained. The Bruker Biotyper MALDI-TOF MS system had a moderate performance in identification of Aspergillus directly inoculated on solid agar media. Continued expansion of the Bruker Biotyper MALDI-TOF MS database and adoption of alternative cutoff values for interpretation are required to improve the performance of the system for identifying highly diverse species of clinically encountered Aspergillus isolates.

  13. Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry System for Identification of Aspergillus Species Directly from Growth on Solid Agar Media.

    Science.gov (United States)

    Li, Ying; Wang, He; Zhao, Yu-Pei; Xu, Ying-Chun; Hsueh, Po-Ren

    2017-01-01

    We evaluated the accuracy of the Bruker Biotyper matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) system at identifying clinical isolates of Aspergillus species that were grown on agar media. A total of 381 non-duplicate Aspergillus isolates representing 21 different Aspergillus species identified by molecular analysis were included in this study. The Bruker Biotyper MALDI-TOF MS system was able to identify 30.2% (115/381) of the isolates to the species level (score values of ≥2.000) and 49.3% to the genus level (score values of 1.700-1.999). When the identification cutoff value was lowered from ≥2.000 to ≥1.700, the species-level identification rate increased to 79.5% with a slight rise of false identification from 2.6 to 5.0%. From another aspect, a correct species-level identification rate of 89% could be reached by the Bruker Biotyper MALDI-TOF MS system regardless of the score values obtained. The Bruker Biotyper MALDI-TOF MS system had a moderate performance in identification of Aspergillus directly inoculated on solid agar media. Continued expansion of the Bruker Biotyper MALDI-TOF MS database and adoption of alternative cutoff values for interpretation are required to improve the performance of the system for identifying highly diverse species of clinically encountered Aspergillus isolates.

  14. Novel, improved sample preparation for rapid, direct identification from positive blood cultures using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.

    Science.gov (United States)

    Schubert, Sören; Weinert, Kirsten; Wagner, Chris; Gunzl, Beatrix; Wieser, Andreas; Maier, Thomas; Kostrzewa, Markus

    2011-11-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used for rapid and reliable identification of bacteria and yeast grown on agar plates. Moreover, MALDI-TOF MS also holds promise for bacterial identification from blood culture (BC) broths in hospital laboratories. The most important technical step for the identification of bacteria from positive BCs by MALDI-TOF MS is sample preparation to remove blood cells and host proteins. We present a method for novel, rapid sample preparation using differential lysis of blood cells. We demonstrate the efficacy and ease of use of this sample preparation and subsequent MALDI-TOF MS identification, applying it to a total of 500 aerobic and anaerobic BCs reported to be positive by a Bactec 9240 system. In 86.5% of all BCs, the microorganism species were correctly identified. Moreover, in 18/27 mixed cultures at least one isolate was correctly identified. A novel method that adjusts the score value for MALDI-TOF MS results is proposed, further improving the proportion of correctly identified samples. The results of the present study show that the MALDI-TOF MS-based method allows rapid (directly from positive BCs and with high accuracy. Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  15. Development of an improved rapid BACpro® protocol and a method for direct identification from blood-culture-positive bottles using matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Yonezawa, Takatoshi; Watari, Tomohisa; Ashizawa, Kazuho; Hanada, Daisuke; Yanagiya, Takako; Watanabe, Naoki; Terada, Takashi; Tomoda, Yutaka; Fujii, Satoshi

    2018-05-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been incorporated into pathogenic bacterial identification methods and has improved their rapidity. Various methods have been reported to directly identify bacteria with MALDI-TOF MS by pretreating culture medium in blood culture bottles. Rapid BACpro® (Nittobo Medical Co., Ltd.) is a pretreatment kit for effective collection of bacteria with cationic copolymers. However, the Rapid BACpro® pretreatment kit is adapted only for MALDI Biotyper (Bruker Daltonics K.K.), and there has been a desire to expand its use to VITEK MS (VMS; bioMerieux SA). We improved the protocol and made it possible to analyze with VMS. The culture medium bacteria collection method was changed to a method with centrifugation after hemolysis using saponin; the cationic copolymer concentration was changed to 30% of the original concentration; the sequence with which reagents were added was changed; and a change was made to an ethanol/formic acid extraction method. The improved protocol enhanced the identification performance. When VMS was used, the identification rate was 100% with control samples. With clinical samples, the identification agreement rate with the cell smear method was 96.3%. The improved protocol is effective in blood culture rapid identification, being both simpler and having an improved identification performance compared with the original. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Direct identification from positive blood broth culture by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Barberino, Maria Goreth; Silva, Marcio de Oliveira; Arraes, Ana Carolina Palmeiras; Correia, Luís Cláudio; Mendes, Ana Verena

    Bloodstream infections (BSIs) are among the most concerning bacterial infections. They are one of the leading causes of morbidity and mortality, and occur in 30-70% of critical care patients. The prompt identification of the causative microorganism can help choosing the appropriate antimicrobial therapy that will lead to better clinical outcomes. Blood culture is one of the most relevant tests for microbiological diagnosis of bacterial infections. The introduction of the MALDI-TOF microbiological diagnosis significantly decreased the time of identifying microorganisms. However, it depends on the growth on solid culture medium. In this study, 538 bottles of positive blood cultures were evaluated to test the accuracy of an in house modified protocol. The study sample consisted of 198 Gram-negative and 350 Gram-positive bacteria. In all, 460 (83.94%) species were identified based on the direct plate findings. The protocol allowed the identification of 185/198 (93.43%) of the Gram-negative bacteria, including aerobes, anaerobes, and non-fermenters, and 275/350 (78.85%) of the Gram-positive bacteria. The proposed method has the potential to provide accurate results in comparison to the traditional method with the potential to reduce the turnaround time for the results and optimize antimicrobial therapy in BSI. Copyright © 2017 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

  17. Direct identification from positive blood broth culture by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS

    Directory of Open Access Journals (Sweden)

    Maria Goreth Barberino

    2017-05-01

    Full Text Available Bloodstream infections (BSIs are among the most concerning bacterial infections. They are one of the leading causes of morbidity and mortality, and occur in 30–70% of critical care patients. The prompt identification of the causative microorganism can help choosing the appropriate antimicrobial therapy that will lead to better clinical outcomes. Blood culture is one of the most relevant tests for microbiological diagnosis of bacterial infections. The introduction of the MALDI-TOF microbiological diagnosis significantly decreased the time of identifying microorganisms. However, it depends on the growth on solid culture medium. In this study, 538 bottles of positive blood cultures were evaluated to test the accuracy of an in house modified protocol. The study sample consisted of 198 Gram-negative and 350 Gram-positive bacteria. In all, 460 (83.94% species were identified based on the direct plate findings. The protocol allowed the identification of 185/198 (93.43% of the Gram-negative bacteria, including aerobes, anaerobes, and non-fermenters, and 275/350 (78.85% of the Gram-positive bacteria. The proposed method has the potential to provide accurate results in comparison to the traditional method with the potential to reduce the turnaround time for the results and optimize antimicrobial therapy in BSI.

  18. Direct calculation of modal contributions to thermal conductivity via Green–Kubo modal analysis

    International Nuclear Information System (INIS)

    Lv, Wei; Henry, Asegun

    2016-01-01

    We derived a new method for direct calculation of the modal contributions to thermal conductivity, which is termed Green–Kubo modal analysis (GKMA). The GKMA method combines the lattice dynamics formalism with the Green–Kubo formula for thermal conductivity, such that the thermal conductivity becomes a direct summation of modal contributions, where one need not define the phonon velocity. As a result, the GKMA method can be applied to any material/group of atoms, where the atoms vibrate around stable equilibrium positions, which includes non-stoichiometric compounds, random alloys, amorphous materials and even rigid molecules. By using molecular dynamics simulations to obtain the time history of each mode’s contribution to the heat current, one naturally includes anharmonicity to full order and can obtain insight into the interactions between different modes through the cross-correlations. As an example, we applied the GMKA method to crystalline and amorphous silicon. The modal contributions at each frequency result from the analysis and thereby allow one to apply a quantum correction to the mode heat capacity to determine the temperature dependence of thermal conductivity. The predicted temperature dependent thermal conductivity for amorphous silicon shows the best agreement with experiments to date. The GKMA method provides new insight into the nature of phonon transport, as it casts the problem in terms of mode–mode correlation instead of scattering, and provides a general unified formalism that can be used to understand phonon–phonon interactions in essentially any class of materials or structures where the atoms vibrate around stable equilibrium sites. (paper)

  19. Study of the mechanisms of heavy-ion induced desorption on accelerator-relevant materials; Untersuchung der Mechanismen schwerioneninduzierter Desorption an beschleunigerrelevanten Materialien

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Markus

    2008-02-22

    The ion beam loss induced desorption is a performance limitation for low charge state heavy ion accelerators. If charge exchanged projectile ions get lost onto the beam pipe, desorption of gas is stimulated resulting in a pressure increase inside of the synchrotron and thus, a dramatically reduction of the beam life time. To minimize the amount of desorbed gas an experimental program has been started to measure the desorption yields (released gas molecules per incident ion) of various materials and different projectile ions. The present work is a contribution to the understanding of the physical processes behind the ion beam loss induced desorption. The yield measurements by the pressure rise method have been combined for the rst time with in situ ion beam analysis technologies such as ERDA and RBS. With this unique method the desorption behavior of a sample can be correlated to its surface and bulk properties. The performed experiments with 1,4 MeV/u Xenon-Ions show that the ion induced desorption is mainly a surface effect. Sputtered oxide layers or impurities do not contribute to the desorbed gas significantly. Nevertheless bulk properties play an important role in the desorption strength. Pure metallic samples desorb less gas than isolating materials under swift heavy ion irradiation. From the experimental results it was possible to estimate the desorption yields of various materials under ion bombardment by means of an extended inelastic thermal-spike-model. The extension is the combination of the thermal-spike's temperature map with thermal desorption. Within this model the ion induced desorption can be regarded as the release of adsorbates from a transient overheated spot on the samples surface around the ion impact. Finally a copper substrate with a gold coated surface was developed and proposed as a suitable material for a beam loss collimator with minimum desorption to ensure the performance of GSI's SIS18 in high current beam operation. (orig.)

  20. VAC*TRAX vacuum thermal desorption

    International Nuclear Information System (INIS)

    1994-09-01

    Pilot VAC*TRAX treatability tests were conducted on RCRA, TSCA, and RCRA/radioactive mixed wastes, to determine the efficiency in remediating organics' contaminated solids. The process volatilizes organic compounds by indirectly heating the feed material in a vacuum batch dryer and condensing the organics separately from the remaining solids. Contaminants included tetrachloroethene, bis(2-ethylhexyl)phthalate, pentachlorophenol, and PCBs. Treatment specifications were met: a tetrachloroethene removal >99.99% and PCB removal from a starting level of 990 ppM to a final level of 3 , as a uranium simulant; the Mo remained in the treated solids, not transferring to the condensate. In the mixed waste tests, uranium present in a feed soil remained in the soil. Economic viability was demonstrated by achieving excellent treatment on a routine basis with both 4 and 6 hour heating cycles

  1. VAC*TRAX vacuum thermal desorption

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-09-01

    Pilot VAC*TRAX treatability tests were conducted on RCRA, TSCA, and RCRA/radioactive mixed wastes, to determine the efficiency in remediating organics` contaminated solids. The process volatilizes organic compounds by indirectly heating the feed material in a vacuum batch dryer and condensing the organics separately from the remaining solids. Contaminants included tetrachloroethene, bis(2-ethylhexyl)phthalate, pentachlorophenol, and PCBs. Treatment specifications were met: a tetrachloroethene removal >99.99% and PCB removal from a starting level of 990 ppM to a final level of <1 ppM. One test run was spiked with MoO{sub 3}, as a uranium simulant; the Mo remained in the treated solids, not transferring to the condensate. In the mixed waste tests, uranium present in a feed soil remained in the soil. Economic viability was demonstrated by achieving excellent treatment on a routine basis with both 4 and 6 hour heating cycles.

  2. Small Reactor Designs Suitable for Direct Nuclear Thermal Propulsion: Interim Report

    International Nuclear Information System (INIS)

    Schnitzler, Bruce G.

    2012-01-01

    open loop systems for direct nuclear thermal propulsion. Although a number of fast spectrum reactor and engine designs suitable for direct nuclear thermal propulsion were proposed and designed, none were built. This report summarizes status results of evaluations of small nuclear reactor designs suitable for direct nuclear thermal propulsion.

  3. Environmental Assisted Fatigue Evaluation of Direct Vessel Injection Piping Considering Thermal Stratification

    International Nuclear Information System (INIS)

    Kim, Taesoon; Lee, Dohwan

    2016-01-01

    As the environmentally assisted fatigue (EAF) due to the primary water conditions is to be a critical issue, the fatigue evaluation for the components and pipes exposed to light water reactor coolant conditions has become increasingly important. Therefore, many studies to evaluate the fatigue life of the components and pipes in LWR coolant environments on fatigue life of materials have been conducted. Among many components and pipes of nuclear power plants, the direct vessel injection piping is known to one of the most vulnerable pipe systems because of thermal stratification occurred in that systems. Thermal stratification occurs because the density of water changes significantly with temperature. In this study, fatigue analysis for DVI piping using finite element analysis has been conducted and those results showed that the results met design conditions related with the environmental fatigue evaluation of safety class 1 pipes in nuclear power plants. Structural and fatigue integrity for the DVI piping system that thermal stratification occurred during the plant operation has conducted. First of all, thermal distribution of the piping system is calculated by computational fluid dynamic analysis to analyze the structural integrity of that piping system. And the fatigue life evaluation considering environmental effects was carried out. Our results showed that the DVI piping system had enough structural integrity and fatigue life during the design lifetime of 60 years

  4. Liquid immersion thermal crosslinking of 3D polymer nanopatterns for direct carbonisation with high structural integrity

    Science.gov (United States)

    Kang, Da-Young; Kim, Cheolho; Park, Gyurim; Moon, Jun Hyuk

    2015-12-01

    The direct pyrolytic carbonisation of polymer patterns has attracted interest for its use in obtaining carbon materials. In the case of carbonisation of nanopatterned polymers, the polymer flow and subsequent pattern change may occur in order to relieve their high surface energies. Here, we demonstrated that liquid immersion thermal crosslinking of polymer nanopatterns effectively enhanced the thermal resistance and maintained the structure integrity during the heat treatment. We employed the liquid immersion thermal crosslinking for 3D porous SU8 photoresist nanopatterns and successfully converted them to carbon nanopatterns while maintaining their porous features. The thermal crosslinking reaction and carbonisation of SU8 nanopatterns were characterised. The micro-crystallinity of the SU8-derived carbon nanopatterns was also characterised. The liquid immersion heat treatment can be extended to the carbonisation of various polymer or photoresist nanopatterns and also provide a facile way to control the surface energy of polymer nanopatterns for various purposes, for example, to block copolymer or surfactant self-assemblies.

  5. Desorption by Femtosecond Laser Pulses : An Electron-Hole Effect?

    OpenAIRE

    D. M., NEWNS; T. F., HEINZ; J. A., MISEWICH; IBM Research Division, T. J. Watson Research Center; IBM Research Division, T. J. Watson Research Center; IBM Research Division, T. J. Watson Research Center

    1992-01-01

    Desorption of molecules from metal surfaces induced by femtosecond visible laser pulses has been reported. Since the lattice temperature rise is insufficient to explain desorption, an electronic mechanism is clearly responsible. It is shown that a theory based on direct coupling between the center-of-mass degree of freedom of the adsorbate and the electron-hole excitations of the substrate provides a satisfactory explanation of the various experimental findings.

  6. Thermal and electrical energy yield analysis of a directly water cooled photovoltaic module

    Directory of Open Access Journals (Sweden)

    Mtunzi Busiso

    2016-01-01

    Full Text Available Electrical energy of photovoltaic modules drops by 0.5% for each degree increase in temperature. Direct water cooling of photovoltaic modules was found to give improved electrical and thermal yield. A prototype was put in place to analyse the field data for a period of a year. The results showed an initial high performance ratio and electrical power output. The monthly energy saving efficiency of the directly water cooled module was found to be approximately 61%. The solar utilisation of the naturally cooled photovoltaic module was found to be 8.79% and for the directly water cooled module its solar utilisation was 47.93%. Implementation of such systems on households may reduce the load from the utility company, bring about huge savings on electricity bills and help in reducing carbon emissions.

  7. Towards understanding thermal history of the Universe through direct and indirect detection of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Roszkowski, Leszek; Trojanowski, Sebastian [National Centre for Nuclear Research, Hoża 69, 00-681 Warsaw (Poland); Turzyński, Krzysztof, E-mail: leszek.roszkowski@ncbj.gov.pl, E-mail: sebastian.trojanowski@uci.edu, E-mail: Krzysztof-Jan.Turzynski@fuw.edu.pl [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw (Poland)

    2017-10-01

    We examine the question to what extent prospective detection of dark matter by direct and indirect- detection experiments could shed light on what fraction of dark matter was generated thermally via the freeze-out process in the early Universe. By simulating putative signals that could be seen in the near future and using them to reconstruct WIMP dark matter properties, we show that, in a model- independent approach this could only be achieved in a thin sliver of the parameter space. However, with additional theoretical input the hypothesis about the thermal freeze-out as the dominant mechanism for generating dark matter can potentially be verified. We illustrate this with two examples: an effective field theory of dark matter with a vector messenger and a higgsino or wino dark matter within the MSSM.

  8. Thermal performance analysis of a direct-expansion solar-assisted heat pump water heater

    International Nuclear Information System (INIS)

    Kong, X.Q.; Zhang, D.; Li, Y.; Yang, Q.M.

    2011-01-01

    A direct-expansion solar-assisted heat pump water heater (DX-SAHPWH) is described, which can supply hot water for domestic use during the whole year. The system mainly employs a bare flat-plate collector/evaporator with a surface area of 4.2 m 2 , an electrical rotary-type hermetic compressor, a hot water tank with the volume of 150 L and a thermostatic expansion valve. R-22 is used as working fluid in the system. A simulation model based on lumped and distributed parameter approach is developed to predict the thermal performance of the system. Given the structure parameters, meteorological parameters, time step and final water temperature, the numerical model can output operational parameters, such as heat capacity, system COP and collector efficiency. Comparisons between the simulation results and the experimental measurements show that the model is able to give satisfactory predictions. The effect of various parameters, including solar radiation, ambient temperature, wind speed and compressor speed, has been analyzed on the thermal performance of the system. -- Highlights: ► A direct-expansion solar-assisted heat pump water heater (DX-SAHPWH) is described. ► A simulation model based on lumped and distributed parameter approach is developed to predict the thermal performance of the system. ► The numerical model can output operational parameters, such as heat capacity, system COP and collector efficiency. ► Comparisons between the simulation results and the experimental measurements show that the model is able to give satisfactory predictions. ► The effect of various parameters has been analyzed on the thermal performance of the system.

  9. Desorption dynamics of deuterium in CuCrZr alloy

    Science.gov (United States)

    Thi Nguyen, Lan Anh; Lee, Sanghwa; Noh, S. J.; Lee, S. K.; Park, M. C.; Shu, Wataru; Pitcher, Spencer; Torcy, David; Guillermain, David; Kim, Jaeyong

    2017-12-01

    Desorption behavior of deuterium (D2) in CuCrZr alloy was investigated considering sample thickness, loading and baking temperature of deuterium followed by the ITER scopes. Cylindrical specimens of 1, 3, 5 mm thick with 4 mm diameter were exposed to deuterium at a pressure of 25 bar at 120, 240 and 350 °C for 24 h, then baked at 800 °C in a vacuum chamber maintained at a pressure lower than 10-7 Torr. Deuterium desorption characteristics such as desorption rate and amount of deuterium in the sample were estimated by analyzing the desorption peaks monitored with a residual gas analyzer (RGA), and the trapping energy of deuterium was calculated using thermal desorption spectroscopy (TDS). Secondary ion mass spectroscopy (SIMS) results showed that deuterium atoms embedded in the sample at a depth of less than 15 μm and desorbed as low as 400 °C. All absorbed deuterium atoms in the specimen were completely retrieved by dynamic pumping at 800 °C in 15 min. The desorption rate of deuterium per unit area was inversely proportional to the increment of the thickness of the sample, and was proportional to the loading temperature. Based on the assumption that a uniform distribution of interstitial sites for deuterium follows the Femi-Dirac statistics, the result of TDS demonstrated that the CuCrZr alloy has two types of trapping energies, which were estimated to be 62 and 79 kJ/mol.

  10. A monoenergetic electron source generated by nuclear stimulated desorption

    International Nuclear Information System (INIS)

    Kelson, I.; Levy, Y.; Nir, D.; Haustein, P.E.

    1994-01-01

    A series of measurements of nuclear stimulated desorption was performed for 103 Ru, using thin ruthenium films irradiated by thermal neutrons. The magnitude, time dependence and electric charge state of the outgoing 103m Rh flux was investigated. The utilization of monoenergetic electrons accompanying the 103 Rh decay for thin film thickness measurement is considered. (Author)

  11. Electrical Thermal Network for Direct Contact Membrane Distillation Modeling and Analysis

    KAUST Repository

    Karam, Ayman M.

    2015-02-04

    Membrane distillation is an emerging water distillation technology that offers several advantages compared to conventional water desalination processes. Although progress has been made to model and understand the physics of the process, many studies are based on steady-state assumptions or are computationally not appropriate for real time control. This paper presents the derivation of a novel dynamical model, based on analogy between electrical and thermal systems, for direct contact membrane distillation (DCMD). The proposed model captures the dynamics of temperature distribution and distilled water flux. To demonstrate the adequacy of the proposed model, validation with transient and steady-state experimental data is presented.

  12. Direct laser writing of polymeric nanostructures via optically induced local thermal effect

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Quang Cong [Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, École Normale Supérieure de Cachan, CentraleSupélec, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan (France); Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, 10000 Hanoi (Viet Nam); Nguyen, Dam Thuy Trang; Do, Minh Thanh; Luong, Mai Hoang; Journet, Bernard; Ledoux-Rak, Isabelle; Lai, Ngoc Diep, E-mail: nlai@lpqm.ens-cachan.fr [Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, École Normale Supérieure de Cachan, CentraleSupélec, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan (France)

    2016-05-02

    We demonstrate the fabrication of desired structures with feature size below the diffraction limit by use of a positive photoresist. The direct laser writing technique employing a continuous-wave laser was used to optically induce a local thermal effect in a positive photoresist, which then allowed the formation of solid nanostructures. This technique enabled us to realize multi-dimensional sub-microstructures by use of a positive photoresist, with a feature size down to 57 nm. This mechanism acting on positive photoresists opens a simple and low-cost way for nanofabrication.

  13. Laser desorption mass spectrometry for biomolecule detection and its applications

    Science.gov (United States)

    Winston Chen, C. H.; Sammartano, L. J.; Isola, N. R.; Allman, S. L.

    2001-08-01

    During the past few years, we developed and used laser desorption mass spectrometry for biomolecule detections. Matrix-assisted laser desorption/ionization (MALDI) was successfully used to detect DNA fragments with the size larger than 3000 base pairs. It was also successfully used to sequence DNA with both enzymatic and chemical degradation methods to produce DNA ladders. We also developed MALDI with fragmentation for direct DNA sequencing for short DNA probes. Since laser desorption mass spectrometry for DNA detection has the advantages of fast speed and no need of labeling, it has a great potential for molecular diagnosis for disease and person identification by DNA fingerprinting. We applied laser desorption mass spectrometry to succeed in the diagnosis of cystic fibrosis and several other nerve degenerative diseases such as Huntington's disease. We also succeeded in demonstrating DNA typing for forensic applications.

  14. Laser desorption mass spectrometry for biomolecule detection and its applications

    International Nuclear Information System (INIS)

    Winston Chen, C.H.; Allman, S.L.; Sammartano, L.J.; Isola, N.R.

    2001-01-01

    During the past few years, we developed and used laser desorption mass spectrometry for biomolecule detections. Matrix-assisted laser desorption/ionization (MALDI) was successfully used to detect DNA fragments with the size larger than 3000 base pairs. It was also successfully used to sequence DNA with both enzymatic and chemical degradation methods to produce DNA ladders. We also developed MALDI with fragmentation for direct DNA sequencing for short DNA probes. Since laser desorption mass spectrometry for DNA detection has the advantages of fast speed and no need of labeling, it has a great potential for molecular diagnosis for disease and person identification by DNA fingerprinting. We applied laser desorption mass spectrometry to succeed in the diagnosis of cystic fibrosis and several other nerve degenerative diseases such as Huntington's disease. We also succeeded in demonstrating DNA typing for forensic applications

  15. Thermal Cracking in Westerly Granite Monitored Using Direct Wave Velocity, Coda Wave Interferometry, and Acoustic Emissions

    Science.gov (United States)

    Griffiths, L.; Lengliné, O.; Heap, M. J.; Baud, P.; Schmittbuhl, J.

    2018-03-01

    To monitor both the permanent (thermal microcracking) and the nonpermanent (thermo-elastic) effects of temperature on Westerly Granite, we combine acoustic emission monitoring and ultrasonic velocity measurements at ambient pressure during three heating and cooling cycles to a maximum temperature of 450°C. For the velocity measurements we use both P wave direct traveltime and coda wave interferometry techniques, the latter being more sensitive to changes in S wave velocity. During the first cycle, we observe a high acoustic emission rate and large—and mostly permanent—apparent reductions in velocity with temperature (P wave velocity is reduced by 50% of the initial value at 450°C, and 40% upon cooling). Our measurements are indicative of extensive thermal microcracking during the first cycle, predominantly during the heating phase. During the second cycle we observe further—but reduced—microcracking, and less still during the third cycle, where the apparent decrease in velocity with temperature is near reversible (at 450°C, the P wave velocity is decreased by roughly 10% of the initial velocity). Our results, relevant for thermally dynamic environments such as geothermal reservoirs, highlight the value of performing measurements of rock properties under in situ temperature conditions.

  16. A predictive thermal dynamic model for parameter generation in the laser assisted direct write process

    International Nuclear Information System (INIS)

    Shang Shuo; Fearon, Eamonn; Wellburn, Dan; Sato, Taku; Edwardson, Stuart; Dearden, G; Watkins, K G

    2011-01-01

    The laser assisted direct write (LADW) method can be used to generate electrical circuitry on a substrate by depositing metallic ink and curing the ink thermally by a laser. Laser curing has emerged over recent years as a novel yet efficient alternative to oven curing. This method can be used in situ, over complicated 3D contours of large parts (e.g. aircraft wings) and selectively cure over heat sensitive substrates, with little or no thermal damage. In previous studies, empirical methods have been used to generate processing windows for this technique, relating to the several interdependent processing parameters on which the curing quality and efficiency strongly depend. Incorrect parameters can result in a track that is cured in some areas and uncured in others, or in damaged substrates. This paper addresses the strong need for a quantitative model which can systematically output the processing conditions for a given combination of ink, substrate and laser source; transforming the LADW technique from a purely empirical approach, to a simple, repeatable, mathematically sound, efficient and predictable process. The method comprises a novel and generic finite element model (FEM) that for the first time predicts the evolution of the thermal profile of the ink track during laser curing and thus generates a parametric map which indicates the most suitable combination of parameters for process optimization. Experimental data are compared with simulation results to verify the accuracy of the model.

  17. Study of the thermal and kinetic parameters during directional solidification of zinc-aluminum eutectic alloys

    International Nuclear Information System (INIS)

    Gueijman, Sergio Fabian; Ares, Alicia Esther; Schvezov, Carlos Enrique

    2008-01-01

    Much work has been done recently on investigating zinc-based binary alloys, with different aluminum content, and modified or not with small amounts of other alloying elements. Some of these alloys have interesting properties, such as, the ZA alloys that have properties similar to some bronzes that are used in applications that require pieces with enough resistance to mechanical stresses. The longitudinal thermal gradients, the minimal gradients, the velocities of the liquid interphases, the velocities of the solid interphases and the accelerations of both interphases as a function of time and position were determined for each diluted alloy of the eutectic concentration considered (Zn-5%Al, % in weight), solidified horizontally with caloric extraction from both ends of the test pieces. The values obtained from the horizontal solidification with two directions of predominant caloric extraction are compared to previous values obtained for the same vertically solidified alloy system with a predominantly caloric extraction direction

  18. The influence of thermal regime on gasoline direct injection engine performance and emissions

    Science.gov (United States)

    Leahu, C. I.; Tarulescu, S.

    2016-08-01

    This paper presents the experimental research regarding to the effects of a low thermal regime on fuel consumption and pollutant emissions from a gasoline direct injection (GDI) engine. During the experimental researches, the temperature of the coolant and oil used by the engine were modified 4 times (55, 65, 75 and 85 oC), monitoring the effects over the fuel consumption and emissions (CO2, CO and NOx). The variations in temperature of the coolant and oil have been achieved through AVL coolant and oil conditioning unit, integrated in the test bed. The obtained experimental results reveals the poor quality of exhaust gases and increases of fuel consumption for the gasoline direct injection engines that runs outside the optimal ranges for coolant and oil temperatures.

  19. Optically and thermally controlled terahertz metamaterial via transition between direct and indirect electromagnetically induced transparency

    Directory of Open Access Journals (Sweden)

    Jiawei Sui

    2014-12-01

    Full Text Available This passage presents a design of tunable terahertz metamaterials via transition between indirect and direct electromagnetically induced transparency (EIT effects by changing semiconductor InSb’s properties to terahertz wave under optical and thermal stimuli. Mechanical model and its electrical circuit model are utilized in analytically calculating maximum transmission of transparency window. Simulated results show consistency with the analytical expressions. The results show that the metamaterials hold 98.4% modulation depth at 189 GHz between 300 K, σInSb =256000 S/m, and 80 K, σInSb =0.0162 S/m conditions , 1360 ps recovery time of the excited electrons in InSb under optical stimulus at 300 K mainly considering the direct EIT effect, and minimum bandwidth 1 GHz.

  20. Improving the thermal stability of cellobiohydrolase Cel7A from Hypocrea jecorina by directed evolution.

    Science.gov (United States)

    Goedegebuur, Frits; Dankmeyer, Lydia; Gualfetti, Peter; Karkehabadi, Saeid; Hansson, Henrik; Jana, Suvamay; Huynh, Vicky; Kelemen, Bradley R; Kruithof, Paulien; Larenas, Edmund A; Teunissen, Pauline J M; Ståhlberg, Jerry; Payne, Christina M; Mitchinson, Colin; Sandgren, Mats

    2017-10-20

    Secreted mixtures of Hypocrea jecorina cellulases are able to efficiently degrade cellulosic biomass to fermentable sugars at large, commercially relevant scales. H. jecorina Cel7A, cellobiohydrolase I, from glycoside hydrolase family 7, is the workhorse enzyme of the process. However, the thermal stability of Cel7A limits its use to processes where temperatures are no higher than 50 °C. Enhanced thermal stability is desirable to enable the use of higher processing temperatures and to improve the economic feasibility of industrial biomass conversion. Here, we enhanced the thermal stability of Cel7A through directed evolution. Sites with increased thermal stability properties were combined, and a Cel7A variant (FCA398) was obtained, which exhibited a 10.4 °C increase in T m and a 44-fold greater half-life compared with the wild-type enzyme. This Cel7A variant contains 18 mutated sites and is active under application conditions up to at least 75 °C. The X-ray crystal structure of the catalytic domain was determined at 2.1 Å resolution and showed that the effects of the mutations are local and do not introduce major backbone conformational changes. Molecular dynamics simulations revealed that the catalytic domain of wild-type Cel7A and the FCA398 variant exhibit similar behavior at 300 K, whereas at elevated temperature (475 and 525 K), the FCA398 variant fluctuates less and maintains more native contacts over time. Combining the structural and dynamic investigations, rationales were developed for the stabilizing effect at many of the mutated sites. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Electrical equivalent thermal network for direct contact membrane distillation modeling and analysis

    KAUST Repository

    Karam, Ayman M.

    2016-09-19

    Membrane distillation (MD) is an emerging water desalination technology that offers several advantages compared to conventional desalination methods. Although progress has been made to model the physics of the process, there are two common limitations of existing models. Firstly, many of the models are based on the steady-state analysis of the process and secondly, some of the models are based on partial differential equations, which when discretized introduce many states which are not accessible in practice. This paper presents the derivation of a novel dynamic model, based on the analogy between electrical and thermal systems, for direct contact membrane distillation (DCMD). An analogous electrical thermal network is constructed and its elements are parameterized such that the response of the network models the DCMD process. The proposed model captures the spatial and temporal responses of the temperature distribution along the flow direction and is able to accurately predict the distilled water flux output. To demonstrate the adequacy of the proposed model, validation with time varying and steady-state experimental data is presented. (C) 2016 Elsevier Ltd. All rights reserved.

  2. Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

    Science.gov (United States)

    Han, Yung-Min; Han, Chulhee; Kim, Wan Ho; Seong, Ho Yong; Choi, Seung-Bok

    2016-09-01

    This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.

  3. Evaluation of Three Parametric Models for Estimating Directional Thermal Radiation from Simulation, Airborne, and Satellite Data

    Directory of Open Access Journals (Sweden)

    Xiangyang Liu

    2018-03-01

    Full Text Available An appropriate model to correct thermal radiation anisotropy is important for the wide applications of land surface temperature (LST. This paper evaluated the performance of three published directional thermal radiation models—the Roujean–Lagouarde (RL model, the Bidirectional Reflectance Distribution Function (BRDF model, and the Vinnikov model—at canopy and pixel scale using simulation, airborne, and satellite data. The results at canopy scale showed that (1 the three models could describe directional anisotropy well and the Vinnikov model performed the best, especially for erectophile canopy or low leaf area index (LAI; (2 the three models reached the highest fitting accuracy when the LAI varied from 1 to 2; and (3 the capabilities of the three models were all restricted by the hotspot effect, plant height, plant spacing, and three-dimensional structure. The analysis at pixel scale indicated a consistent result that the three models presented a stable effect both on verification and validation, but the Vinnikov model had the best ability in the erectophile canopy (savannas and grassland and low LAI (barren or sparsely vegetated areas. Therefore, the Vinnikov model was calibrated for different land cover types to instruct the angular correction of LST. Validation with the Surface Radiation Budget Network (SURFRAD-measured LST demonstrated that the root mean square (RMSE of the Moderate Resolution Imaging Spectroradiometer (MODIS LST product could be decreased by 0.89 K after angular correction. In addition, the corrected LST showed better spatial uniformity and higher angular correlation.

  4. Study of the mechanisms of heavy-ion induced desorption on accelerator-relevant materials

    International Nuclear Information System (INIS)

    Bender, Markus

    2008-01-01

    The ion beam loss induced desorption is a performance limitation for low charge state heavy ion accelerators. If charge exchanged projectile ions get lost onto the beam pipe, desorption of gas is stimulated resulting in a pressure increase inside of the synchrotron and thus, a dramatically reduction of the beam life time. To minimize the amount of desorbed gas an experimental program has been started to measure the desorption yields (released gas molecules per incident ion) of various materials and different projectile ions. The present work is a contribution to the understanding of the physical processes behind the ion beam loss induced desorption. The yield measurements by the pressure rise method have been combined for the rst time with in situ ion beam analysis technologies such as ERDA and RBS. With this unique method the desorption behavior of a sample can be correlated to its surface and bulk properties. The performed experiments with 1,4 MeV/u Xenon-Ions show that the ion induced desorption is mainly a surface effect. Sputtered oxide layers or impurities do not contribute to the desorbed gas significantly. Nevertheless bulk properties play an important role in the desorption strength. Pure metallic samples desorb less gas than isolating materials under swift heavy ion irradiation. From the experimental results it was possible to estimate the desorption yields of various materials under ion bombardment by means of an extended inelastic thermal-spike-model. The extension is the combination of the thermal-spike's temperature map with thermal desorption. Within this model the ion induced desorption can be regarded as the release of adsorbates from a transient overheated spot on the samples surface around the ion impact. Finally a copper substrate with a gold coated surface was developed and proposed as a suitable material for a beam loss collimator with minimum desorption to ensure the performance of GSI's SIS18 in high current beam operation. (orig.)

  5. Anomalous low-temperature desorption from preirradiated rare gas solids

    International Nuclear Information System (INIS)

    Savchenko, E.V.; Gumenchuk, G.B.; Yurtaeva, E.M.; Belov, A.G.; Khyzhniy, I.V.; Frankowski, M.; Beyer, M.K.; Smith-Gicklhorn, A.M.; Ponomaryov, A.N.; Bondybey, V.E.

    2005-01-01

    The role for the exciton-induced defects in the stimulation of anomalous low-temperature desorption of the own lattice atoms from solid Ar and Ne preirradiated by an electron beam is studied. The free electrons from shallow traps-structural defects-was monitored by the measurements of a yield of the thermally induced exoelectron emission (TSEE). The reaction of recombination of self-trapped holes with electrons is considered as a source of energy needed for the desorption of atoms from the surface of preirradiated solids. A key part of the exciton-induced defects in the phenomenon observed is demonstrated

  6. Indirect and direct measurement of thermal neutron acceleration by inelastic scattering on the 177Lu isomer

    International Nuclear Information System (INIS)

    Belier, G.; Roig, O.; Meot, V.; Daugas, J.M.; Aupiais, J.; Jutier, Ch.; Le Petit, G.; Veyssiere, Ch.

    2008-01-01

    When neutrons interact with isomers, these isomers can de-excite and in such a reaction the outgoing neutron has an energy greater than the in-going one. This process is referred as Inelastic Neutron Acceleration or Super-elastic Scattering. Up to now this process was observed for only two nucleus, 152m Eu and 180m Hf by measuring the number of fast neutrons produced by isomeric targets irradiated with thermal neutrons. In these experiments the energies of the accelerated neutrons were not measured. This report presents an indirect measurement of inelastic neutron acceleration on 177m Lu, based on the burn-up and the radiative capture cross sections measurements. Since at thermal energies the inelastic scattering and the radiative capture are the only processes that contribute to the isomer burn-up, the inelastic cross section can be deduced from the difference between the two measured quantities. Applying this method for the 177 Lu isomer with different neutron fluxes we obtained a value of (257 ± 50) barns (for a temperature of 323 K) and determined that there is no integral resonance for this process. In addition the radiative capture cross section on 177g Lu was measured with a much better accuracy than the accepted value. Since the acceleration cross section is quite high, a direct measurement of this process was undertaken, sending thermal neutrons and measuring the fast neutrons. The main goal now is to measure the outgoing neutron energies in order to identify the neutron transitions in the exit channel. In particular the K conservation question can be addressed by such a measurement. (author)

  7. Direct dimethyl ether (DME) synthesis through a thermally coupled heat exchanger reactor

    International Nuclear Information System (INIS)

    Vakili, R.; Pourazadi, E.; Setoodeh, P.; Eslamloueyan, R.; Rahimpour, M.R.

    2011-01-01

    Compared to some of the alternative fuel candidates such as methane, methanol and Fischer-Tropsch fuels, dimethyl ether (DME) seems to be a superior candidate for high-quality diesel fuel in near future. The direct synthesis of DME from syngas would be more economical and beneficial in comparison with the indirect process via methanol synthesis. Multifunctional auto-thermal reactors are novel concepts in process intensification. A promising field of applications for these concepts could be the coupling of endothermic and exothermic reactions in heat exchanger reactors. Consequently, in this study, a double integrated reactor for DME synthesis (by direct synthesis from syngas) and hydrogen production (by the cyclohexane dehydrogenation) is modelled based on the heat exchanger reactors concept and a steady-state heterogeneous one-dimensional mathematical model is developed. The corresponding results are compared with the available data for a pipe-shell fixed bed reactor for direct DME synthesis which is operating at the same feed conditions. In this novel configuration, DME production increases about 600 Ton/year. Also, the effects of some operational parameters such as feed flow rates and the inlet temperatures of exothermic and endothermic sections on reactor behaviour are investigated. The performance of the reactor needs to be proven experimentally and tested over a range of parameters under practical operating conditions.

  8. Kinetics of Hydrogen Absorption and Desorption in Titanium

    Directory of Open Access Journals (Sweden)

    Suwarno Suwarno

    2017-10-01

    Full Text Available Titanium is reactive toward hydrogen forming metal hydride which has a potential application in      energy storage and conversion. Titanium hydride has been widely studied for hydrogen storage, thermal storage, and battery electrodes applications. A special interest is using titanium for hydrogen production in a hydrogen sorption-enhanced steam reforming of natural gas. In the present work, non-isothermal dehydrogenation kinetics of titanium hydride and kinetics of hydrogenation in gaseous flow at isothermal conditions were investigated. The hydrogen desorption was studied using temperature desorption spectroscopy (TDS while the hydrogen absorption and desorption in gaseous flow were studied by temperature programmed desorption (TPD. The present work showed that the path of dehydrogenation of the TiH2 is d®b®a hydride phase with possible overlapping steps occurred. The fast hydrogen desorption rate observed at the TDS main peak temperature were correlated with the fast transformation of the d-TiH1.41 to b-TiH0.59. In the gaseous flow, hydrogen absorption and desorption were related to the transformation of b-TiH0.59 Û d-TiH1.41 with 2 wt.% hydrogen reversible content. Copyright © 2017 BCREC Group. All rights reserved Received: 21st November 2016; Revised: 20th March 2017; Accepted: 9th April 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Suwarno, S., Yartys, V.A. (2017. Kinetics of Hydrogen Absorption and Desorption in Titanium. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3: 312-317  (doi:10.9767/bcrec.12.3.810.312-317

  9. Ultrasound assisted simultaneous reduction and direct functionalization of graphene oxide with thermal and cytotoxicity profile.

    Science.gov (United States)

    Maktedar, Shrikant S; Avashthi, Gopal; Singh, Man

    2017-01-01

    The new sonochemical approach for simultaneous reduction and direct functionalization of graphene oxide (GrO) has been developed. The GrO was functionalized with 2-Aminobenzoxazole (2-ABOZ) in twenty min with complete deletion of hazardous steps. The significance of ultrasound was exemplified with the comparative conventional methods. The newly prepared f-(2-ABOZ)GrO was extensively characterized with near edge X-ray absorption fine structure (NEXAFS) spectroscopy, 13 C solid state NMR, XPS, XRD, HRTEM, SAED, AFM, Raman, UV-vis, FTIR and TGA. The thermal stability of f-(2-ABOZ)GrO was confirmed with total percentage weight loss in TGA. The biological activity of f-(2-ABOZ)GrO was explored with MCF-7 and Vero cell lines. The inherent cytotoxicity was evaluated with SRB assay at 10, 20, 40 and 80μgmL -1 . The estimated cell viabilities were >78% with f-(2-ABOZ) GrO. A high cytocompatibility of f-(2-ABOZ)GrO was ensured with in vitro evaluation on living cell lines, and low toxicity of f-(2-ABOZ)GrO was confirmed its excellent biocompatibility. The morphological effect on Vero cell line evidently supports the formation of biocompatible f-(2-ABOZ)GrO. Therefore, f-(2-ABOZ)GrO was emerged as an advanced functional material for thermally stable biocompatible coatings. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Acetate self-mixing and direct thermal reaction for preparation of LiCoO2

    International Nuclear Information System (INIS)

    Jung, Bum-Young; Kang, Hyun-Koo; Jeong, In-Seong; Han, Kyoo-Seung; Lee, Youngil; Choo, Jaebum; Ryu, Kwang Sun

    2004-01-01

    Layered LiCoO 2 as a cathode material for rechargeable lithium battery is prepared using the acetate self-mixing method. Using this method, the preparation procedure consists of just two steps: spontaneous and homogeneous mixing of molten acetates at 80 deg. C, as well as direct thermal reaction at high temperature without any pulverization, grinding, agglomeration, particle morphology controlling, particle size controlling, and even artificial stirring of reactants. When lithium and cobalt acetates are exposed to the temperature of 80 deg. C, they can be fluidized substances by themselves without any solvents and spontaneously mixed together. In this way, layered LiCoO 2 phase is prepared by just simple heat treatment. The heating at 350 deg. C is interposed to accomplish steady intermediate phase translation without any intermittent cooling. The 7 Li MAS NMR and Raman spectra upon the thermal exposure of the reactants demonstrate the feature of the spontaneous mixing process of the molten reactants. The LiCoO 2 prepared by the acetate self-mixing method show quite prospective properties as a cathode material for lithium rechargeable battery, an initial discharge capacity of 149.5 mAh/g and the discharge capacity retention of 98.9% and 97.5% after 10 and 20 cycles, respectively

  11. Repeated Thermal Stress, Shading, and Directional Selection in the Florida Reef Tract

    Directory of Open Access Journals (Sweden)

    Robert van Woesik

    2017-06-01

    Full Text Available Over the last three decades reef corals have been subjected to an unprecedented frequency and intensity of thermal-stress events, which have led to extensive coral bleaching, disease, and mortality. Over the next century, the climate is predicted to drive sea-surface temperatures to even higher levels, consequently increasing the risk of mass bleaching and disease outbreaks. Yet, there is considerable temporal and spatial variation in coral bleaching and in disease prevalence. Using data collected from 2,398 sites along the Florida reef tract from 2005 to 2015, this study examined the temporal and spatial patterns of coral bleaching and disease in relation to coral-colony size, depth, temperature, and chlorophyll-a concentrations. The results show that coral bleaching was most prevalent during the warmest years in 2014 and 2015, and disease was also most prevalent in 2010, 2014, and 2015. Although the majority of the corals surveyed were found in habitats with low chlorophyll-a concentrations, and high irradiance, these same habitats showed the highest prevalence of coral bleaching and disease outbreaks during thermal-stress events. These results suggest that directional selection in a warming ocean may favor corals able to tolerate inshore, shaded environments with high turbidity and productivity.

  12. Design, fabrication, and application of a directional thermal processing system for controlled devitrification of metallic glasses

    Science.gov (United States)

    Meyer, Megan Anne Lamb

    The potential of using metallic glass as a pathway to obtaining novel morphologies and metastable phases has been garnering attention since their discovery. Several rapid solidification techniques; such as gas atomization, melt spinning, laser melting, and splat quenching produce amorphous alloys. A directional thermal processing system (DTPS) was designed, fabricated and characterized for the use of zone processing or gradient-zone processing of materials. Melt-spun CuZr metallic glass alloy was subjected to the DTPS and the relaxation and crystallization responses of the metallic glass were characterized. A range of processing parameters were developed and analyzed that would allow for devitrification to occur. The relaxation and crystallization responses were compared with traditional heat treatment methods of metallic glasses. The new processing method accessed equilibrium and non-equilibrium phases of the alloy and the structures were found to be controllable and sensitive to processing conditions. Crystallized fraction, crystallization onset temperature, and structural relaxation were controlled through adjusting the processing conditions, such as the hot zone temperature and sample velocity. Reaction rates computed from isothermal (TTT) transformation data were not found to be reliable, suggesting that the reaction kinetics are not additive. This new processing method allows for future studying of the thermal history effects of metallic glasses.

  13. High temperature thermal conductivity measurements of UO2 by Direct Electrical Heating. Final report

    International Nuclear Information System (INIS)

    Bassett, B.

    1980-10-01

    High temperature properties of reactor type UO 2 pellets were measured using a Direct Electrical Heating (DEH) Facility. Modifications to the experimental apparatus have been made so that successful and reproducible DEH runs may be carried out while protecting the pellets from oxidation at high temperature. X-ray diffraction measurements on the UO 2 pellets have been made before and after runs to assure that sample oxidation has not occurred. A computer code has been developed that will model the experiment using equations that describe physical properties of the material. This code allows these equations to be checked by comparing the model results to collected data. The thermal conductivity equation for UO 2 proposed by Weilbacher has been used for this analysis. By adjusting the empirical parameters in Weilbacher's equation, experimental data can be matched by the code. From the several runs analyzed, the resulting thermal conductivity equation is lambda = 1/4.79 + 0.0247T/ + 1.06 x 10 -3 exp[-1.62/kT/] - 4410. exp[-3.71/kT/] where lambda is in w/cm K, k is the Boltzman constant, and T is the temperature in Kelvin

  14. Thermally induced structural evolution and performance of mesoporous block copolymer-directed alumina perovskite solar cells.

    KAUST Repository

    Tan, Kwan Wee

    2014-04-11

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI(3-x)Cl(x)) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI(3-x)Cl(x) material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance.

  15. Thermally induced structural evolution and performance of mesoporous block copolymer-directed alumina perovskite solar cells.

    KAUST Repository

    Tan, Kwan Wee; Moore, David T; Saliba, Michael; Sai, Hiroaki; Estroff, Lara A; Hanrath, Tobias; Snaith, Henry J; Wiesner, Ulrich

    2014-01-01

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI(3-x)Cl(x)) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI(3-x)Cl(x) material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance.

  16. Thermally Induced Structural Evolution and Performance of Mesoporous Block Copolymer-Directed Alumina Perovskite Solar Cells

    Science.gov (United States)

    2015-01-01

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI3–xClx) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI3–xClx material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance. PMID:24684494

  17. Highly directional transurethral ultrasound applicators with rotational control for MRI-guided prostatic thermal therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Anthony B [Thermal Therapy Research Group, UCSF Radiation Oncology, San Francisco, CA (United States); Diederich, Chris J [Thermal Therapy Research Group, UCSF Radiation Oncology, San Francisco, CA (United States); Nau, William H [Thermal Therapy Research Group, UCSF Radiation Oncology, San Francisco, CA (United States); Gill, Harcharan [Department of Urology, Stanford University, Stanford, CA (United States); Bouley, Donna M [Department of Comparative Medicine, Stanford University, Stanford, CA (United States); Daniel, Bruce [Department of Radiology, Stanford University, Stanford, CA (United States); Rieke, Viola [Department of Radiology, Stanford University, Stanford, CA (United States); Butts, R Kim [Department of Radiology, Stanford University, Stanford, CA (United States); Sommer, Graham [Department of Radiology, Stanford University, Stanford, CA (United States)

    2004-01-21

    Transurethral ultrasound applicators with highly directional energy deposition and rotational control were investigated for precise treatment of benign prostatic hyperplasia (BPH) and adenocarcinoma of the prostate (CaP). Two types of catheter-based applicators were fabricated, using either sectored tubular (3.5 mm OD x 10 mm) or planar transducers (3.5 mm x 10 mm). They were constructed to be MRI compatible, minimally invasive and allow for manual rotation of the transducer array within a 10 mm cooling balloon. In vivo evaluations of the applicators were performed in canine prostates (n 3) using MRI guidance (0.5 T interventional magnet). MR temperature imaging (MRTI) utilizing the proton resonance frequency shift method was used to acquire multiple-slice temperature overlays in real time for monitoring and guiding the thermal treatments. Post-treatment T1-weighted contrast-enhanced imaging and triphenyl tetrazolium chloride stained tissue sections were used to define regions of tissue coagulation. Single sonications with the tubular applicator ) produced coagulated zones covering a wedge of the prostate extending from 1-2 mm outside the urethra to the outer boundary of the gland (16 mm radial coagulation). Single sonications with the planar applicator (15-20 W, 10 min, {approx}8 MHz) generated thermal lesions of {approx}30 extending to the prostate boundary. Multiple sequential sonications (sweeping) of a planar applicator (12 W with eight rotations of 30 each) demonstrated controllable coagulation of a 270 contiguous section of the prostate extending to the capsule boundary. The feasibility of using highly directional transurethral ultrasound applicators with rotational capabilities to selectively coagulate regions of the prostate while monitoring and controlling the treatments with MRTI was demonstrated in this study.

  18. Overview of direct air free cooling and thermal energy storage potential energy savings in data centres

    International Nuclear Information System (INIS)

    Oró, Eduard; Depoorter, Victor; Pflugradt, Noah; Salom, Jaume

    2015-01-01

    In the last years the total energy demand of data centres has experienced a dramatic increase which is expected to continue. This is why data centres industry and researchers are working on implementing energy efficiency measures and integrating renewable energy to overcome energy dependence and to reduce operational costs and CO 2 emissions. The cooling system of these unique infrastructures can account for 40% of the total energy consumption. To reduce the energy consumption, free cooling strategies are used more and more, but so far there has been little research about the potential of thermal energy storage (TES) solutions to match energy demand and energy availability. Hence, this work intends to provide an overview of the potential of the integration of direct air free cooling strategy and TES systems into data centres located at different European locations. For each location, the benefit of using direct air free cooling is evaluated energetically and economically for a data centre of 1250 kW. The use of direct air free cooling is shown to be feasible. This does not apply the TES systems by itself. But when using TES in combination with an off-peak electricity tariff the operational cooling cost can be drastically reduced. - Highlights: • The total annual hours for direct air free cooling in data centres are calculated. • The potential of TES integration in data centres is evaluated. • The implementation of TES to store the ambient air cold is not recommended. • TES is feasible if combined with redundant chillers and off-peak electricity price. • The cooling electricity cost is being reduced up to 51%, depending on the location

  19. Novel, Improved Sample Preparation for Rapid, Direct Identification from Positive Blood Cultures Using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry

    OpenAIRE

    Schubert, Sören; Weinert, Kirsten; Wagner, Chris; Gunzl, Beatrix; Wieser, Andreas; Maier, Thomas; Kostrzewa, Markus

    2011-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used for rapid and reliable identification of bacteria and yeast grown on agar plates. Moreover, MALDI-TOF MS also holds promise for bacterial identification from blood culture (BC) broths in hospital laboratories. The most important technical step for the identification of bacteria from positive BCs by MALDI-TOF MS is sample preparation to remove blood cells and host proteins. We present a m...

  20. Absorption/desorption in sprays

    International Nuclear Information System (INIS)

    Naimpally, A.

    1987-01-01

    This survey paper shall seek to present the present state of knowledge concerning absorption and desorption in spray chambers. The first part of the paper presents the theories and formulas for the atomization and break-up of sprays in nozzles. Formulas for the average (sauter-mean) diameters are then presented. For the case of absorption processes, the formulas for the dimensionless mass transfer coefficients is in drops. The total; mass transfer is the total of the transfer in individual drops. For the case of desorption of sparingly soluble gases from liquids in a spray chamber, the mass transfer occurs in the spray just at the point of break-up of the jet. Formulas for the desorption of gases are presented

  1. Coverage dependent desorption dynamics of deuterium on Si(100) surfaces: interpretation with a diffusion-promoted desorption model.

    Science.gov (United States)

    Matsuno, T; Niida, T; Tsurumaki, H; Namiki, A

    2005-01-08

    We studied coverage dependence of time-of-flight (TOF) spectra of D2 molecules thermally desorbed from the D/Si(100) surface. The mean translational energies Et of desorbed D2 molecules were found to increase from 0.20+/-0.05 eV to 0.40+/-0.04 eV as the desorption coverage window was decreased from 1.0 ML> or =thetaD> or =0.9 ML to 0.2 ML> or =thetaD> or =0 ML, being consistent with the kinetics switch predicted in the interdimer mechanism. The measured TOF spectra were deconvoluted into 2H, 3H, and 4H components by a curve fitting method along the principle of detailed balance. As a result, it turned out that the desorption kinetics changes from the 4H to the 3H situation at high coverage above thetaD=0.9 ML, while the 2H desorption is dominant for a quite wide coverage region up to thetaD=0.8 ML. A dynamic desorption mechanism by which the desorption is promoted by D-atom diffusion to dangling bonds was proposed. 2005 American Institute of Physics.

  2. Measuremental analysis of thermal performance of direct gain houses in Kanto district. Effects of thermal mass and caves; Kanto chiho ni tatsu direct gain jutaku no netsuseino jissoku. Netsuyoryo to hisashi no koka

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, K; Sunaga, N; Muro, K [Tokyo Metropolitan University, Tokyo (Japan)

    1996-10-27

    The thermal performance of direct gain passive solar houses was measured. Mr. M`s two-storied RC residence with double glazing windows and thermal storage floors, walls and ceilings of brick or concrete was provided for measurement. Its double eaves of the south window and both SE and SW overhanging exterior walls play a role in sunshade. Mr. I`s two-storied wooden residence with thermal storage RC floors and brick walls, and no eaves of the south window and no overhanging exterior walls was also provided. The summer and winter measurement results were in complete contrast between the residences. In summer, large thermal mass and eaves of Mr. M`s residence were effective, while in winter, small thermal mass and no eaves of Mr. I`s residence were effective. The following ideas are important in design from the viewpoint of indoor thermal environment: a movable sunshade for taking in solar radiation as much as possible in winter, well-balanced arrangement of thermal storage parts with suitable thermal mass corresponding to movement of the sun, a large screen door for cross ventilation in summer, and a night insulation shutter for reducing heat loss in winter. 2 refs., 10 figs., 1 tab.

  3. Data compilation for particle impact desorption

    International Nuclear Information System (INIS)

    Oshiyama, Takashi; Nagai, Siro; Ozawa, Kunio; Takeuchi, Fujio.

    1984-05-01

    The desorption of gases from solid surfaces by incident electrons, ions and photons is one of the important processes of hydrogen recycling in the controlled thermonuclear reactors. We have surveyed the literature concerning the particle impact desorption published through 1983 and compiled the data on the desorption cross sections and desorption yields with the aid of a computer. This report presents the results obtained for electron stimulated desorption, the desorption cross sections and yields being given in graphs and tables as functions of incident electron energy, surface temperature and gas exposure. (author)

  4. Laser aided direct metal deposition of Inconel 625 superalloy: Microstructural evolution and thermal stability

    International Nuclear Information System (INIS)

    Dinda, G.P.; Dasgupta, A.K.; Mazumder, J.

    2009-01-01

    Direct metal deposition technology is an emerging laser aided manufacturing technology based on a new additive manufacturing principle, which combines laser cladding with rapid prototyping into a solid freeform fabrication process that can be used to manufacture near net shape components from their CAD files. In the present study, direct metal deposition technology was successfully used to fabricate a series of samples of the Ni-based superalloy Inconel 625. A high power CO 2 laser was used to create a molten pool on the Inconel 625 substrate into which an Inconel 625 powder stream was delivered to create a 3D object. The structure and properties of the deposits were investigated using optical and scanning electron microscopy, X-ray diffraction and microhardness test. The microstructure has been found to be columnar dendritic in nature, which grew epitaxially from the substrate. The thermal stability of the dendritic morphology was investigated in the temperature range 800-1200 deg. C. These studies demonstrate that Inconel 625 is an attractive material for laser deposition as all samples produced in this study are free from relevant defects such as cracks, bonding error and porosity.

  5. Laser aided direct metal deposition of Inconel 625 superalloy: Microstructural evolution and thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Dinda, G.P., E-mail: dindag@focushope.edu [Center for Advanced Technologies, Focus: HOPE, Detroit, MI 48238 (United States); Center for Laser Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI 48109 (United States); Dasgupta, A.K. [Center for Advanced Technologies, Focus: HOPE, Detroit, MI 48238 (United States); Mazumder, J. [Center for Laser Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI 48109 (United States)

    2009-05-25

    Direct metal deposition technology is an emerging laser aided manufacturing technology based on a new additive manufacturing principle, which combines laser cladding with rapid prototyping into a solid freeform fabrication process that can be used to manufacture near net shape components from their CAD files. In the present study, direct metal deposition technology was successfully used to fabricate a series of samples of the Ni-based superalloy Inconel 625. A high power CO{sub 2} laser was used to create a molten pool on the Inconel 625 substrate into which an Inconel 625 powder stream was delivered to create a 3D object. The structure and properties of the deposits were investigated using optical and scanning electron microscopy, X-ray diffraction and microhardness test. The microstructure has been found to be columnar dendritic in nature, which grew epitaxially from the substrate. The thermal stability of the dendritic morphology was investigated in the temperature range 800-1200 deg. C. These studies demonstrate that Inconel 625 is an attractive material for laser deposition as all samples produced in this study are free from relevant defects such as cracks, bonding error and porosity.

  6. Numerical Prediction of a Bi-Directional Micro Thermal Flow Sensors

    Directory of Open Access Journals (Sweden)

    M. Al-Amayrah

    2011-09-01

    Full Text Available Thermal flow sensors such as hot-wire anemometer (HWA can be used to measure the flow velocity with certain accuracy. However, HWA can measure the flow velocity without determining the flow direction. Pulsed-Wire Anemometer (PWA with 3 wires can be used to measure flow velocity and flow directions. The present study aims to develop a numerical analysis of unsteady flow around a pulsed hot-wire anemometer using three parallel wires. The pulsed wire which is called the heated wire is located in the middle and the two sensor wires are installed upstream and downstream of the pulsed wire. 2-D numerical models were built and simulated using different wires arrangements. The ratio of the separation distance between the heated wire and sensor wire (x to the diameter of the heated wire (D ratios (x/D was varied between 3.33 and 183.33. The output results are plotted as a function of Peclet number (convection time / diffusion time. It was found that as the ratio of x/D increases, the sensitivity of PWA device to the time of flight decreases. But at the same the reading of the time of flight becomes more accurate, because the effects of the diffusion and wake after the heated wire decrease. Also, a very good agreement has been obtained between the present numerical simulation and the previous experimental data.

  7. Direct fitness correlates and thermal consequences of facultative aggregation in a desert lizard.

    Directory of Open Access Journals (Sweden)

    Alison R Davis Rabosky

    Full Text Available Social aggregation is a common behavioral phenomenon thought to evolve through adaptive benefits to group living. Comparing fitness differences between aggregated and solitary individuals in nature--necessary to infer an evolutionary benefit to living in groups--has proven difficult because communally-living species tend to be obligately social and behaviorally complex. However, these differences and the mechanisms driving them are critical to understanding how solitary individuals transition to group living, as well as how and why nascent social systems change over time. Here we demonstrate that facultative aggregation in a reptile (the Desert Night Lizard, Xantusia vigilis confers direct reproductive success and survival advantages and that thermal benefits of winter huddling disproportionately benefit small juveniles, which can favor delayed dispersal of offspring and the formation of kin groups. Using climate projection models, however, we estimate that future aggregation in night lizards could decline more than 50% due to warmer temperatures. Our results support the theory that transitions to group living arise from direct benefits to social individuals and offer a clear mechanism for the origin of kin groups through juvenile philopatry. The temperature dependence of aggregation in this and other taxa suggests that environmental variation may be a powerful but underappreciated force in the rapid transition between social and solitary behavior.

  8. Thermal Inactivation of Mycobacterium avium subsp. paratuberculosis in Artificially Contaminated Milk by Direct Steam Injection

    Science.gov (United States)

    Butot, Sophie; Jagadeesan, Balamurugan; Bakker, Douwe; Donaghy, John

    2016-01-01

    ABSTRACT The efficiency of direct steam injection (DSI) at 105°C for 3 s to inactivate Mycobacterium avium subsp. paratuberculosis in milk at a pilot-plant scale was investigated. Milk samples were artificially contaminated with M. avium subsp. paratuberculosis and also with cow fecal material naturally infected with M. avium subsp. paratuberculosis. We also tested milk artificially contaminated with Mycobacterium smegmatis as a candidate surrogate to compare thermal inactivation between M. smegmatis and M. avium subsp. paratuberculosis. Following the DSI process, no viable M. avium subsp. paratuberculosis or M. smegmatis was recovered using culture methods for both strains. For pure M. avium subsp. paratuberculosis cultures, a minimum reduction of 5.6 log10 was achieved with DSI, and a minimum reduction of 5.7 log10 was found with M. smegmatis. The minimum log10 reduction for wild-type M. avium subsp. paratuberculosis naturally present in feces was 3.3. In addition, 44 dairy and nondairy powdered infant formula (PIF) ingredients used during the manufacturing process of PIF were tested for an alternate source for M. avium subsp. paratuberculosis and were found to be negative by quantitative PCR (qPCR). In conclusion, the results obtained from this study indicate that a >7-fold-log10 reduction of M. avium subsp. paratuberculosis in milk can be achieved with the applied DSI process. IMPORTANCE M. avium subsp. paratuberculosis is widespread in dairy herds in many countries. M. avium subsp. paratuberculosis is the causative agent of Johne's disease in cattle, and infected animals can directly or indirectly (i.e., fecal contamination) contaminate milk. Despite much research and debate, there is no conclusive evidence that M. avium subsp. paratuberculosis is a zoonotic bacterium, i.e., one that causes disease in humans. The presence of M. avium subsp. paratuberculosis or its DNA has been reported in dairy products, including pasteurized milk, cheese, and infant formula

  9. Gas desorption properties of ammonia borane and metal hydride composites

    International Nuclear Information System (INIS)

    Matin, M.R.

    2009-01-01

    'Full text': Ammonia borane (NH 3 BH 3 ) has been of great interest owing to its ideal combination of low molecular weight and high H 2 storage capacity of 19.6 mass %, which exceeds the current capacity of gasoline. DOE's year 2015 targets involve gravimetric as well as volumetric energy densities. In this work, we have investigated thermal decomposition of ammonia borane and calcium hydride composites at different molar ratio. The samples were prepared by planetary ball milling under hydrogen gas atmosphere pressure of 1Mpa at room temperature for 2, and 10 hours. The gas desorption properties were examined by thermal desorption mass spectroscopy (TDMS). The identification of phases was carried out by X-ray diffraction. The results obtain were shown in fig (a),(b),and (c). Hydrogen desorption properties were observed at all molar ratios, but the desorption temperature is significantly lower at around 70 o C at molar ratio 1:1 as shown in fig (c), and unwanted gas (ammonia) emissions were remarkably suppressed by mixing with the calcium hydride. (author)

  10. Effect of Working Fluids on the Thermal Performance of a Bi-directional Solar Thermodiode

    International Nuclear Information System (INIS)

    Ko, Yung Joo

    2008-02-01

    (Smart Module System) were made. Six kinds of working fluids were used to investigate their effects on the thermal performance of a bi-directional solar thermo diode. Two kinds of thermo diodes were studied. The first one is the mono-directional thermo diode that allows heat flow in the desired direction but blocks in the opposite direction. The second one is the bi-directional thermo diode of which the direction of heat flow, surface absorptivity and heat capacity of the module can be adjusted for maximum energy efficiency. This hi-directional can be used both for the summer cooling and winter heating of buildings and shelters. Usually, the thermo diodes are simple beam shape, but in this study, they were redesigned a s two L-shaped loops mounted between a collector plate and a Storage tank. Rotable joints between the horizontal and inclined segments of the loop enable easy alteration of geat transfer direction. The loops and tank were filled with a working fluid for effective heat transfer when the solar thermo diode was forwarded biased. The solar thermo diode was heated by a radiant heater that consisted of 20 halogen lamps that generates a heat flux of about 1000W/m 2 on the collector surface. The working fluids used in the study were water, acetone, ethylalcohol. In addition, three kinds of silicon oil with different viscosity were studied. And three mixtures of water and ethylalcohol of different volume ratio were used. Finally, the nano fluids were also studied. Working fluids were tested with thermal conductivity values ranging from 0.1 to 0.56 W/m- .deg. C, thermal expansion coefficient values ranging from 1.8 x 10 -4 to 1.3 x 10 -3 K -1 , and kinematic viscosity values ranging from 0.65 x 10 -6 to 100 x 10 -6 m 2 /s. Through the study, it was found that the circulation point(CP) at the onset of fluid flow is very important. for a given working fluid, the heat transfer and heated stability of the system depends strongly on the circulation point of the fluid

  11. SPS Ion Induced Desorption Experiment

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    This experiment will give a study about the induced desorption from heavy ion (Indium ion run from week 45 in SPS T4-H8 area) impacting LHC type graphite collimator. 4 different samples are located in the 4 chambers 90° one to each other: pure graphite, graphite with copper coating, graphite with NEG coating, 316LN stainless steal (reference).

  12. Carbon tetrachloride desorption from activated carbon

    International Nuclear Information System (INIS)

    Jonas, L.A.; Sansone, E.B.

    1981-01-01

    Carbon tetrachloride was desorbed from a granular activated carbon subsequent to its adsorption under various vapor exposure periods. The varied conditions of exposure resulted in a range of partially saturated carbon beds which, when followed by a constant flow rate for desorption, generated different forms of the desorbing concentration versus time curve. A method of analyzing the desorption curves is presented which permits extraction of the various desorbing rates from the different desorption and to relate this to the time required for such regeneration. The Wheeler desorption kinetic equation was used to calculate the pseudo first order desorption rate constant for the carbon. The desorption rate constant was found to increase monotonically with increasing saturation of the bed, permitting the calculation of the maximum desorption rate constant for the carbon at 100% saturation. The Retentivity Index of the carbon, defined as the dimensionless ratio of the adsorption to the desorption rate constant, was found to be 681

  13. A Direct Simulation Monte Carlo Model Of Thermal Escape From Titan

    Science.gov (United States)

    Johnson, Robert E.; Tucker, O. J.

    2008-09-01

    Recent analysis of density profiles vs. altitude from the Ion Neutral Mass Spectrometer (INMS) on Cassini (Waite et al. 2005) suggest Titan could have loss a significant amount of atmosphere in 4 Gyr at present escape rates (e.g., Johnson 2008). Strobel 2008 applied a slow hydrodynamic escape model to Titan's atmosphere using solar heating below the exobase to drive upward thermal conduction and power escape. However, near the exobase continuum models become problematic as a result of the increasing rarefaction in the atmosphere. The microscopic nature of DSMC is directly suitable to model atmosphere flow in nominal exobase region (e.g., Michael et. al. 2005). Our Preliminary DSMC models have shown no evidence for slow hydrodynamic escape of N2 and CH4 from Titan's atmosphere using boundary conditions normalized to the atmospheric properties in Strobel (2008). In this paper we use a 1D radial Direct Simulation Monte Carlo (DSMC) model of heating in Titan's upper atmosphere to estimate the escape rate as a function of the Jean's parameter. In this way we can test under what conditions the suggested deviations from Jeans escape would occur. In addition, we will be able to extract the necessary energy deposition to power the heavy molecule loss rates suggested in recent models (Strobel 2008; Yelle et. al. 2008). Michael, M. Johnson, R.E. 2005 Energy Deposition of pickup ions and heating of Titan's atmosphere. Planat. Sp. Sci. 53, 1510-1514 Johnson, R.E., "Sputtering and Heating of Titan's Upper Atmosphere", Proc Royal Soc. (London) (2008) Strobel, D.F. 2008 Titan's hydrodynamically escaping atmosphere. Icarus 193, 588-594 Yelle, R.V., J. Cui and I. C.F. Muller-Wodarg 2008 Methane Escape from Titan's Atmosphere. J. Geophys. Res in press Waite, J.H., Jr., Niemann, H.B., Yelle, R.V. et al. 2005 Ion Neutral Mass Spectrometer Results from the First Flyby of Titan. Science 308, 982-986

  14. Direct chemical oxidation: a non-thermal technology for the destruction of organic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, G.B.; Cooper, J. F.; Lewis, P. R.; Adamson, M. G.

    1998-02-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment and chemical demilitarization and decontamination at LLNL since 1992, and is applicable to the destruction of virtually all solid or liquid organics, including: chlorosolvents, oils and greases, detergents, organic-contaminated soils or sludges, explosives, chemical and biological warfare agents, and PCB's. [1-15] The process normally operates at 80-100 C, a heating requirement which increases the difficulty of surface decontamination of large objects or, for example, treatment of a wide area contaminated soil site. The driver for DCO work in FY98 was thus to investigate the use of catalysts to demonstrate the effectiveness of the technology for organics destruction at temperatures closer to ambient. In addition, DCO is at a sufficiently mature stage of development that technology transfer to a commercial entity was a logical next step, and was thus included in FY98 tasks.

  15. Experimental investigation on photothermal properties of nanofluids for direct absorption solar thermal energy systems

    International Nuclear Information System (INIS)

    He, Qinbo; Wang, Shuangfeng; Zeng, Shequan; Zheng, Zhaozhi

    2013-01-01

    Highlights: • The factors affecting the transmittance of Cu–H 2 O nanofluids were studied with UV–Vis–NIR spectrophotometer. • The optical properties of Cu–H 2 O nanofluids were studied through the theoretical model. • The Cu–H 2 O nanofluids can enhance the absorption ability for solar energy. - Abstract: In this article, Cu–H 2 O nanofluids were prepared through two-step method. The transmittance of nanofluids over solar spectrum (250–2500 nm) was measured by the UV–Vis–NIR spectrophotometer based on integrating sphere principle. The factors influencing transmittance of nanofluids, such as particle size, mass fraction and optical path were investigated. The extinction coefficients measured experimentally were compared with the theoretical calculation value. Meanwhile, the photothermal properties of nanofluids were also investigated. The experimental results show that the transmittance of Cu–H 2 O nanofluids is much less than that of deionized water, and decreases with increasing nanoparticle size, mass fraction and optical depth. The highest temperature of Cu–H 2 O nanofluids (0.1 wt.%) can increased up to 25.3% compared with deionized water. The good absorption ability of Cu–H 2 O nanofluids for solar energy indicates that it is suitable for direct absorption solar thermal energy systems

  16. Multiscale 3D manufacturing: combining thermal extrusion printing with additive and subtractive direct laser writing

    Science.gov (United States)

    Malinauskas, Mangirdas; Lukoševičius, Laurynas; MackevičiÅ«tÄ--, DovilÄ--; BalčiÅ«nas, Evaldas; RekštytÄ--, Sima; Paipulas, Domas

    2014-05-01

    A novel approach for efficient manufacturing of three-dimensional (3D) microstructured scaffolds designed for cell studies and tissue engineering applications is presented. A thermal extrusion (fused filament fabrication) 3D printer is employed as a simple and low-cost tabletop device enabling rapid materialization of CAD models out of biocompatible and biodegradable polylactic acid (PLA). Here it was used to produce cm- scale microporous (pore size varying from 100 to 400 µm) scaffolds. The fabricated objects were further laser processed in a direct laser writing (DLW) subtractive (ablation) and additive (lithography) manners. The first approach enables precise surface modification by creating micro-craters, holes and grooves thus increasing the surface roughness. An alternative way is to immerse the 3D PLA scaffold in a monomer solution and use the same DLW setup to refine its inner structure by fabricating dots, lines or a fine mesh on top as well as inside the pores of previously produced scaffolds. The DLW technique is empowered by ultrafast lasers - it allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. Structure geometry on macro- to micro- scales could be finely tuned by combining these two fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro- featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of ms, microfluidics, microoptics and many others.

  17. Influence of Crucible Thermal Conductivity on Crystal Growth in an Industrial Directional Solidification Process for Silicon Ingots

    Directory of Open Access Journals (Sweden)

    Zaoyang Li

    2016-01-01

    Full Text Available We carried out transient global simulations of heating, melting, growing, annealing, and cooling stages for an industrial directional solidification (DS process for silicon ingots. The crucible thermal conductivity is varied in a reasonable range to investigate its influence on the global heat transfer and silicon crystal growth. It is found that the crucible plays an important role in heat transfer, and therefore its thermal conductivity can influence the crystal growth significantly in the entire DS process. Increasing the crucible thermal conductivity can shorten the time for melting of silicon feedstock and growing of silicon crystal significantly, and therefore large thermal conductivity is helpful in saving both production time and power energy. However, the high temperature gradient in the silicon ingots and the locally concave melt-crystal interface shape for large crucible thermal conductivity indicate that high thermal stress and dislocation propagation are likely to occur during both growing and annealing stages. Based on the numerical simulations, some discussions on designing and choosing the crucible thermal conductivity are presented.

  18. Laser induced desorption as hydrogen retention diagnostic method

    Energy Technology Data Exchange (ETDEWEB)

    Zlobinski, Miroslaw

    2016-07-15

    Laser Induced Desorption Spectroscopy (LIDS) is a diagnostic method to measure the hydrogen content in the surface of a material exposed to a hydrogen isotope (H,D,T) plasma. It is developed mainly to monitor hydrogen retention in the walls of magnetic fusion devices that have to limit the amount of their fuel tritium mainly due to safety reasons. The development of fusion increasingly focusses on plasma-wall interactions for which in situ diagnostics like LIDS are required that work during plasma operation and without tile removal. The method has first been developed for thin amorphous hydrocarbon (a-C:H < 500 nm) layers successfully and is studied in the present work on thick (15 μm) layers, carbon fibre composites (CFCs), bulk tungsten (W), W fuzz and mixed C/W materials. In LID a 3 ms Nd:YAG (1064 nm) laser pulse heats a spot of diameter 3 mm with 500 {sup MW}/{sub m{sup 2}} on W to 1800 K at the surface and thus above 1300 K within ca. 0.2 mm depth. On C materials (graphite, CFC, a-C:H) this temperature guarantees a nearly complete (>95%) desorption already within 1.5 ms pulse duration. The retained hydrogen atoms are desorbed locally, recombine to molecules and migrate promptly to the surface via internal channels like pores and grain boundaries. Whereas, in W the retained hydrogen atoms have to diffuse through the bulk material, which is a relatively slow process also directed into the depth. The desorbed hydrogen fraction can thus be strongly reduced to 18-91% as observed here. This fraction is measured by melting the central part of a previously heated spot ca. 40 μm deep with a diameter 2 mm, 3 ms laser pulse, releasing the remaining hydrogen. W samples exposed to different plasmas in TEXTOR, Pilot-PSI, PSI-2, PADOS and PlaQ show that the desorption fraction of LID mainly decreases due to higher sample temperature during plasma exposure. The heat causes deeper hydrogen diffusion and/or stronger hydrogen trapping due to creation of traps with higher

  19. Laser induced desorption as hydrogen retention diagnostic method

    International Nuclear Information System (INIS)

    Zlobinski, Miroslaw

    2016-01-01

    Laser Induced Desorption Spectroscopy (LIDS) is a diagnostic method to measure the hydrogen content in the surface of a material exposed to a hydrogen isotope (H,D,T) plasma. It is developed mainly to monitor hydrogen retention in the walls of magnetic fusion devices that have to limit the amount of their fuel tritium mainly due to safety reasons. The development of fusion increasingly focusses on plasma-wall interactions for which in situ diagnostics like LIDS are required that work during plasma operation and without tile removal. The method has first been developed for thin amorphous hydrocarbon (a-C:H < 500 nm) layers successfully and is studied in the present work on thick (15 μm) layers, carbon fibre composites (CFCs), bulk tungsten (W), W fuzz and mixed C/W materials. In LID a 3 ms Nd:YAG (1064 nm) laser pulse heats a spot of diameter 3 mm with 500 MW / m 2 on W to 1800 K at the surface and thus above 1300 K within ca. 0.2 mm depth. On C materials (graphite, CFC, a-C:H) this temperature guarantees a nearly complete (>95%) desorption already within 1.5 ms pulse duration. The retained hydrogen atoms are desorbed locally, recombine to molecules and migrate promptly to the surface via internal channels like pores and grain boundaries. Whereas, in W the retained hydrogen atoms have to diffuse through the bulk material, which is a relatively slow process also directed into the depth. The desorbed hydrogen fraction can thus be strongly reduced to 18-91% as observed here. This fraction is measured by melting the central part of a previously heated spot ca. 40 μm deep with a diameter 2 mm, 3 ms laser pulse, releasing the remaining hydrogen. W samples exposed to different plasmas in TEXTOR, Pilot-PSI, PSI-2, PADOS and PlaQ show that the desorption fraction of LID mainly decreases due to higher sample temperature during plasma exposure. The heat causes deeper hydrogen diffusion and/or stronger hydrogen trapping due to creation of traps with higher binding energy

  20. Optimisation of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

    DEFF Research Database (Denmark)

    Modi, Anish; Haglind, Fredrik

    2014-01-01

    Central receiver solar thermal power plants are regarded as one of the promising ways to generate electricity in near future. They offer the possibility of using high temperatures and pressures to achieve high efficiencies with standard power cycles. A direct steam generation approach can be used...

  1. XPS study of influence of exposure to air on thermal stability and kinetics of hydrogen decomposition of MgH{sub 2} films obtained by direct hydrogenation from gaseous phase of metallic Mg

    Energy Technology Data Exchange (ETDEWEB)

    Dobrovolsky, V.D., E-mail: dobersh@ipms.kiev.ua; Khyzhun, O.Y.; Sinelnichenko, A.K.; Ershova, O.G.; Solonin, Y.M.

    2017-02-15

    Highlights: • Air influence on thermal stability of MgH{sub 2} have been studied by XPS. • XPS spectra of MgH{sub 2} films obtained at different hydrogen pressures have been studied. • Changes in the chemical state of MgH{sub 2} films depending on time of exposure to air are analyzed. • Correlation exists between chemical surface condition of MgH{sub 2} films and their thermal stableness. • Process of hydrogen desorption from MgH{sub 2} films is studied using TDS for model samples. - Abstract: Mechanism of influence of exposure to air on thermal stability of MgH{sub 2} obtained by direct hydrogenation from the gas phase, the nature of the hydride sensitivity to the negative impact of air and the role of its surface chemical state have not been studied enough. The present article presents data of X-ray photoelectron spectroscopy (XPS) measurements of the Mg 2s, O 1s, C 1s core-level spectra of surface of hydride MgH{sub 2} films derived by gas phase hydrogenation of model samples of metallic Mg, and the evolution of changes in the chemical state of the surface of the hydride films depending on the time of exposure to air and formation conditions (hydrogen pressure and hydrogenation regime). Based on results of XPS, X-ray diffraction (XRD), and thermodesorption spectroscopy (TDS), the existence of a relationship (correlation) between chemical surface condition of hydride MgH{sub 2} films obtained at different hydrogen pressures (3.0 MPa and 11.5 MPa) and their thermal stableness and temperature of the beginning of hydride decomposition has been established.

  2. Direct measurement of thermal effusivity of foods by front configuration of the photpyroelectric method

    NARCIS (Netherlands)

    Szafner, G.; Bicanic, D.D.; Kulcsár, R.; Doka, O.

    2014-01-01

    Thermophysical properties of foods are of considerable relevance to food industry. The One among less explored thermophysical quantities is the thermal effusivity. In this paper the front variant of the photopyroelectric method was applied to determine thermal effusivity of both, fresh hen egg¿s

  3. Layered thermal metamaterials for the directing and harvesting of conductive heat

    Directory of Open Access Journals (Sweden)

    P. R. Bandaru

    2015-05-01

    Full Text Available The utility of a metamaterial, assembled from two layers of nominally isotropic materials, for thermal energy re-orientation and harvesting is examined. A study of the underlying phenomena related to heat flux manipulation, exploiting the anisotropy of the thermal conductivity tensor, is a focus. The notion of the assembled metamaterial as an effective thermal medium forms the basis for many of these investigations and will be probed. An overarching aim is to implement in such thermal metamaterials, functionalities well known from light optics, such as reflection and refraction, which in turn may yield insights on efficient thermal lensing. Consequently, the harness and dissipation of heat, which are for example, of much importance in energy conservation and improving electrical device performance, may be accomplished. The possibilities of energy harvesting, through exploiting anisotropic thermopower in the metamaterials is also examined. The review concludes with a brief survey of the outstanding issues and insights needed for further progress.

  4. Hydrogen desorption from hydrogen fluoride and remote hydrogen plasma cleaned silicon carbide (0001) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    King, Sean W., E-mail: sean.king@intel.com; Tanaka, Satoru; Davis, Robert F. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Nemanich, Robert J. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2015-09-15

    Due to the extreme chemical inertness of silicon carbide (SiC), in-situ thermal desorption is commonly utilized as a means to remove surface contamination prior to initiating critical semiconductor processing steps such as epitaxy, gate dielectric formation, and contact metallization. In-situ thermal desorption and silicon sublimation has also recently become a popular method for epitaxial growth of mono and few layer graphene. Accordingly, numerous thermal desorption experiments of various processed silicon carbide surfaces have been performed, but have ignored the presence of hydrogen, which is ubiquitous throughout semiconductor processing. In this regard, the authors have performed a combined temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) investigation of the desorption of molecular hydrogen (H{sub 2}) and various other oxygen, carbon, and fluorine related species from ex-situ aqueous hydrogen fluoride (HF) and in-situ remote hydrogen plasma cleaned 6H-SiC (0001) surfaces. Using XPS, the authors observed that temperatures on the order of 700–1000 °C are needed to fully desorb C-H, C-O and Si-O species from these surfaces. However, using TPD, the authors observed H{sub 2} desorption at both lower temperatures (200–550 °C) as well as higher temperatures (>700 °C). The low temperature H{sub 2} desorption was deconvoluted into multiple desorption states that, based on similarities to H{sub 2} desorption from Si (111), were attributed to silicon mono, di, and trihydride surface species as well as hydrogen trapped by subsurface defects, steps, or dopants. The higher temperature H{sub 2} desorption was similarly attributed to H{sub 2} evolved from surface O-H groups at ∼750 °C as well as the liberation of H{sub 2} during Si-O desorption at temperatures >800 °C. These results indicate that while ex-situ aqueous HF processed 6H-SiC (0001) surfaces annealed at <700 °C remain terminated by some surface C–O and

  5. Association/dissociation in dense gases and adsorption/desorption on surfaces

    International Nuclear Information System (INIS)

    Flannery, M.R.

    1984-01-01

    A new comprehensive theory is described for the time evolution towards equilibrium of association and dissociation in a dense gas. Expressions are formulated and are illustrated for the net probabilities of association to stable vibrational levels and dissociation to the continuum from an arbitrary bound vibrational level via collision with the thermal gas bath. A general variational principle emerges: The rate which corresponds to the overall direction of the process always adjusts itself to a minimum and the time evolution towards equilibrium is hindered. Analogy is established with Kirchhoff's Laws and Tellegen's Theorem for electrical networks, and with the Principle of Least Dissipation basic to thermodynamics, heat conduction, and fluid mechanics. The theory can also be modified to provide the first basic microscopic account of Associative Desorption of atoms from and Dissociative Chemisorption of molecules to surfaces

  6. Observation of the adsorption and desorption of vibrationally excited molecules on a metal surface

    Science.gov (United States)

    Shirhatti, Pranav R.; Rahinov, Igor; Golibrzuch, Kai; Werdecker, Jörn; Geweke, Jan; Altschäffel, Jan; Kumar, Sumit; Auerbach, Daniel J.; Bartels, Christof; Wodtke, Alec M.

    2018-06-01

    The most common mechanism of catalytic surface chemistry is that of Langmuir and Hinshelwood (LH). In the LH mechanism, reactants adsorb, become thermalized with the surface, and subsequently react. The measured vibrational (relaxation) lifetimes of molecules adsorbed at metal surfaces are in the range of a few picoseconds. As a consequence, vibrational promotion of LH chemistry is rarely observed, with the exception of LH reactions occurring via a molecular physisorbed intermediate. Here, we directly detect adsorption and subsequent desorption of vibrationally excited CO molecules from a Au(111) surface. Our results show that CO (v = 1) survives on a Au(111) surface for 1 × 10-10 s. Such long vibrational lifetimes for adsorbates on metal surfaces are unexpected and pose an interesting challenge to the current understanding of vibrational energy dissipation on metal surfaces. They also suggest that vibrational promotion of surface chemistry might be more common than is generally believed.

  7. Out-of-plane platforms with bi-directional thermal bimorph actuation for transducer applications

    KAUST Repository

    Conchouso Gonzalez, David; Carreno, Armando Arpys Arevalo; Castro, D.; Foulds, Ian G.

    2015-01-01

    This paper reports on the Buckled Cantilever Platform (BCP) that allows the manipulation of the out of plane structures through the adjustment of the pitch angle using thermal bimorph micro-Actuators. Due to the micro-fabrication process used

  8. Coverage-dependent adsorption and desorption of oxygen on Pd(100)

    Energy Technology Data Exchange (ETDEWEB)

    Dunnen, Angela den; Jacobse, Leon; Wiegman, Sandra; Juurlink, Ludo B. F., E-mail: l.juurlink@chem.leidenuniv.nl [Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden (Netherlands); Berg, Otto T. [Department of Chemistry, California State University Fresno, 2555 E. San Ramon Ave., Fresno, California 93740 (United States)

    2016-06-28

    We have studied the adsorption and desorption of O{sub 2} on Pd(100) by supersonic molecular beam techniques and thermal desorption spectroscopy. Adsorption measurements on the bare surface confirm that O{sub 2} initially dissociates for all kinetic energies between 56 and 380 meV and surface temperatures between 100 and 600 K via a direct mechanism. At and below 150 K, continued adsorption leads to a combined O/O{sub 2} overlayer. Dissociation of molecularly bound O{sub 2} during a subsequent temperature ramp leads to unexpected high atomic oxygen coverages, which are also obtained at high incident energy and high surface temperature. At intermediate temperatures and energies, these high final coverages are not obtained. Our results show that kinetic energy of the gas phase reactant and reaction energy dissipated during O{sub 2} dissociation on the cold surface both enable activated nucleation of high-coverage surface structures. We suggest that excitation of local substrate phonons may play a crucial role in oxygen dissociation at any coverage.

  9. Adsorption and temperature-programmed desorption of hydrogen with dispersed platinum and platinum-gold catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J.R.; Foger, K.; Breakspere, R.J.

    1979-05-01

    Adsorption and temperature-programmed desorption of hydrogen with dispersed platinum and platinum-gold catalysts was studied with 0.9-3Vertical Bar3< platinum on silica gel, aerosil, sodium and lanthanum Y zeolites, and ..gamma..-alumina, and on aerosil-supported gold-platinum alloys containing 2, 10, 24, 33, and 85Vertical Bar3< gold. Surface enrichment with gold in the alloy systems, as derived from hydrogen adsorption data and predicted from surface enrichment theory and electron microscopic measurements of particle size, were in good agreement, which indicated that equilibrium was achieved by the thermal treatment (oxygen at 573/sup 0/K, hydrogen at 620/sup 0/K, repeated cycles) used. Hydrogen spillover to gold was observed at the higher hydrogen pressures tested on the alloys with high gold content, and to the zeolite supports. The temperature-programed desorption profiles were independent of gold content, which indicated that gold acts only as diluent, and that isolated surface platinum atoms become populated with hydrogen atoms either by hydrogen atom spillover from platinum ensembles to gold and from the gold to the isolated platinum, and/or by adsorption of a molecule directly on the isolated platinum and chemisorption of one H atom at an adjacent gold atom. The distribution of surface platinum ensembles was evaluated by a computer simulation method.

  10. High Surface Area of Porous Silicon Drives Desorption of Intact Molecules

    Science.gov (United States)

    Northen, Trent R.; Woo, Hin-Koon; Northen, Michael T.; Nordström, Anders; Uritboonthail, Winnie; Turner, Kimberly L.; Siuzdak, Gary

    2007-01-01

    The surface structure of porous silicon used in desorption/ionization on porous silicon (DIOS) mass analysis is known to play a primary role in the desorption/ionization (D/I) process. In this study, mass spectrometry and scanning electron microscopy (SEM) are used to examine the correlation between intact ion generation with surface ablation, and surface morphology. The DIOS process is found to be highly laser energy dependent and correlates directly with the appearance of surface ions (Sin+ and OSiH+). A threshold laser energy for DIOS is observed (10 mJ/cm2), which supports that DIOS is driven by surface restructuring and is not a strictly thermal process. In addition, three DIOS regimes are observed which correspond to surface restructuring and melting. These results suggest that higher surface area silicon substrates may enhance DIOS performance. A recent example which fits into this mechanism is silicon nanowires surface which have a high surface energy and concomitantly requires lower laser energy for analyte desorpton. PMID:17881245

  11. Investigation on the asymmetry of thermal condition and grain defect formation in the customary directional solidification process

    International Nuclear Information System (INIS)

    Ma, D; Wu, Q; Hollad, S; Bührig-Polaczek, A

    2012-01-01

    In the present study, the non-uniformity of the thermal condition and the corresponding grain defect formation in the customary Bridgman process were investigated. The casting clusters in radial alignment were directionally solidified in a Bridgman furnace. It was found that in the casting cluster, the shadow side facing the central rod was ineffectively heated in the hot zone and ineffectively cooled in the cooling zone during withdrawal, compared with the heater side facing the furnace heater. The metallographic examination of the simplified turbine blades exhibited that the platforms on the shadow side are very prone to stray grain formation, while the heater side reveals a markedly lower tendency for that. The asymmetric thermal condition causes the asymmetrical formation of these grain defects. This non-uniformity of the thermal condition should be minimized as far as possible, in order to effectively optimize the quality of the SC superalloy components.

  12. Nuclear stimulated desorption as a potential tool for surface study

    International Nuclear Information System (INIS)

    Nir, Dror.

    1993-03-01

    The described research work constitutes a base for an experimental method to be implemented in the study of solid surfaces. Nuclear Stimulated Desorption (NSD) is a new mode of experimentation in thin film and surface physics. It Is based on the interplay between nuclear phenomena (reactions and spontaneous decays), and atomic - scale induced effects on surfaces and very thin films. One may distinguish between two generically different relationships between the two. First, the dynamics of the nuclear reaction -primarily the recoil of the nucleus - may effect the position of the atom or molecule containing it. Second, the nuclear reaction (or decay) may serve as an analytical indicator of the whereabouts of the atom, or molecule, in question. In nuclear stimulated desorption, both thee aspects combine in an essential way. Namely, one employs a series of two consecutive decays (normally weak decays or isomeric transition) . The first of these decays causes the nucleus to desorb from a surface onto which it had been placed; the second serves to determine the position of the daughter and thereby the characteristics of the primary desorption . The essential feature in NSD is that it occurs almost exclusively from the outermost surface layer. This is because we choose to work with nuclei whose recoil energy Is of the same order of magnitude of the binding energy of the atom to the surface . Furthermore, the desorption probability and its angular (and temporal) characteristics, depend on the features (topology, morphology) of its immediate neighborhood. This work describes experiments which were designed to give relevant, phenomenological information about the outgoing flux of the radioactive daughters (for specifically chosen nuclear species) , and in particular the magnitude of the flux, its time dependence and its charged state. In addition. the basic phenomena itself is being distinguished from competing processes (thermal desorption, in particular). We will now

  13. Effect of thermal cycling on the microstructure of a directionally solidified Fe, Cr, Al-TaC eutectic alloy

    Science.gov (United States)

    Harf, F. H.; Tewari, S. N.

    1977-01-01

    Cylindrical bars (1.2 cm diameter) of Fe-13.6Cr-3.7Al-9TaC (wt %) eutectic alloy were directionally solidified in a modified Bridgman type furnace at 1 cm/h. The alloy microstructure consisted of aligned TaC fibers imbedded in a bcc Fe-Cr-Al matrix. Specimens of the alloy were thermally cycled from 1100 to 425 C in a burner rig. The effects of 1800 thermal cycles on the microstructure was examined by scanning electron microscopy, revealing a zig-zag shape of TaC fibers aligned parallel to the growth direction. The mechanism of carbide solution and reprecipitation on the (111) easy growth planes, suggested previously to account for the development of irregular serrations in Co-Cr-Ni matrix alloys, is believed to be responsible for these zig-zag surfaces.

  14. Modeling of hydrogen desorption from tungsten surface

    Energy Technology Data Exchange (ETDEWEB)

    Guterl, J., E-mail: jguterl@ucsd.edu [University of California, San Diego, La Jolla, CA 92093 (United States); Smirnov, R.D. [University of California, San Diego, La Jolla, CA 92093 (United States); Krasheninnikov, S.I. [University of California, San Diego, La Jolla, CA 92093 (United States); Nuclear Research National University MEPhI, Moscow 115409 (Russian Federation); Uberuaga, B.; Voter, A.F.; Perez, D. [Los Alamos National Laboratory, Los Alamos, NM 8754 (United States)

    2015-08-15

    Hydrogen retention in metallic plasma-facing components is among key-issues for future fusion devices. For tungsten, which has been chosen as divertor material in ITER, hydrogen desorption parameters experimentally measured for fusion-related conditions show large discrepancies. In this paper, we therefore investigate hydrogen recombination and desorption on tungsten surfaces using molecular dynamics simulations and accelerated molecular dynamics simulations to analyze adsorption states, diffusion, hydrogen recombination into molecules, and clustering of hydrogen on tungsten surfaces. The quality of tungsten hydrogen interatomic potential is discussed in the light of MD simulations results, showing that three body interactions in current interatomic potential do not allow to reproduce hydrogen molecular recombination and desorption. Effects of surface hydrogen clustering on hydrogen desorption are analyzed by introducing a kinetic model describing the competition between surface diffusion, clustering and recombination. Different desorption regimes are identified and reproduce some aspects of desorption regimes experimentally observed.

  15. On the thermal cyclic loading behaviour of a directional eutectic superalloy based on the Co-Cr-C system

    International Nuclear Information System (INIS)

    Hildebrandt, U.W.; Nicoll, A.R.

    1981-01-01

    Various modifications of the eutectic, directionally solidified superalloy 73 C were investigated with respect to creep fatigue effects. This was carried out using a thermal cycling apparatus where a mechanical uniaxial load could be applied. A high volume fraction of carbides had an impairing effect on fatigue life. An improvement, however, could be obtained using low concentrations of refractory elements which form monocarbides. (orig.) [de

  16. Hydrogen desorption kinetics from zirconium hydride and zirconium metal in vacuum

    International Nuclear Information System (INIS)

    Hu, Xunxiang; Terrani, Kurt A.; Wirth, Brian D.

    2014-01-01

    The kinetics of hydrogen desorption from zirconium hydride is important in many nuclear design and safety applications. In this paper, a coordinated experimental and modeling study has been used to explicitly demonstrate the applicability of existing kinetic theories for hydrogen desorption from zirconium hydride and α-zirconium. A static synthesis method was used to produce δ-zirconium hydride, and the crystallographic phases of the zirconium hydride were confirmed by X-ray diffraction (XRD). Three obvious stages, involving δ-zirconium hydride, a two-phase region, and α-zirconium, were observed in the hydrogen desorption spectra of two zirconium hydride specimens with H/Zr ratios of 1.62 and 1.64, respectively, which were obtained using thermal desorption spectroscopy (TDS). A continuous, one-dimensional, two-phase moving boundary model, coupled with the zero- and second-order kinetics of hydrogen desorption from δ-zirconium hydride and α-zirconium, respectively, has been developed to reproduce the TDS experimental results. A comparison of the modeling predictions with the experimental results indicates that a zero-order kinetic model is valid for description of hydrogen flux away from the δ-hydride phase, and that a second-order kinetic model works well for hydrogen desorption from α-Zr if the activation energy of desorption is optimized to be 70% of the value reported in the literature

  17. Magnesium growth in magnesium deuteride thin films during deuterium desorption

    Energy Technology Data Exchange (ETDEWEB)

    Checchetto, R., E-mail: riccardo.checchetto@unitn.it [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Miotello, A. [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Mengucci, P.; Barucca, G. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche, I-60131 Ancona (Italy)

    2013-12-15

    Highlights: ► Highly oriented Pd-capped magnesium deuteride thin films. ► The MgD{sub 2} dissociation was studied at temperatures not exceeding 100 °C. ► The structure of the film samples was analyzed by XRD and TEM. ► The transformation is controlled by the re-growth velocity of the Mg layers. ► The transformation is thermally activated, activation energy value of 1.3 ± 0.1 eV. -- Abstract: Pd- capped nanocrystalline magnesium thin films having columnar structure were deposited on Si substrate by e-gun deposition and submitted to thermal annealing in D{sub 2} atmosphere to promote the metal to deuteride phase transformation. The kinetics of the reverse deuteride to metal transformation was studied by Thermal Desorption Spectroscopy (TDS) while the structure of the as deposited and transformed samples was analyzed by X-rays diffraction and Transmission Electron Microscopy (TEM). In Pd- capped MgD{sub 2} thin films the deuteride to metal transformation begins at the interface between un-reacted Mg and transformed MgD{sub 2} layers. The D{sub 2} desorption kinetics is controlled by MgD{sub 2}/Mg interface effects, specifically the re-growth velocity of the Mg layers. The Mg re-growth has thermally activated character and shows an activation energy value of 1.3 ± 0.1 eV.

  18. Catalitic effect of Co on hydrogen desorption form nanostucturated magnesium hydride

    Directory of Open Access Journals (Sweden)

    Matović Ljiljana Lj.

    2008-01-01

    Full Text Available To study the influence of 3d transition metal addition on desorption kinetics of MgH2 ball milling of MgH2-Co blends was performed under Ar. Microstructural and morphological characterization, performed by XRD and SEM, show a huge correlation with thermal stability and hydrogen desorption properties investigated by DSC. A complex desorption behavior is correlated with the dispersion of the metal additive particles on hydride matrix. The activation energy for H2 desorption from MgH2-Co composite was calculated from both non-isothermal and isothermal methods to be 130 kJ/mol which means that mutually diffusion and nucleation and growth of new phase control the dehydration process.

  19. Direct measurement of thermal effusivity of avian eggs and theur constituents: A photopyroelectric study

    NARCIS (Netherlands)

    Szafner, G.; Bicanic, D.D.; Kovacsne, K.; Doka, O.

    2012-01-01

    The front configuration photopyroelectric method has been used to determine, in a nondestructive fashion, thermal effusivity of the yolk and the white of eggs of several bird species as well as of the blends of a single egg yolk and egg white (also called liquid eggs) of different avian eggs.

  20. Direct observation of the thermal demagnetization of magnetic vortex structures in nonideal magnetite recorders

    DEFF Research Database (Denmark)

    Almeida, Trevor P.; Muxworthy, Adrian R.; Kovács, András

    2016-01-01

    The thermal demagnetization of pseudo-single-domain (PSD) magnetite (Fe3O4) particles, which govern the magnetic signal in many igneous rocks, is examined using off-axis electron holography. Visualization of a vortex structure held by an individual Fe3O4 particle (~250nm in diameter) during in situ...

  1. Stable Isotope Systematics of Coalbed Gas during Desorption and Production

    Directory of Open Access Journals (Sweden)

    Martin Niemann

    2017-06-01

    Full Text Available The stable carbon isotope ratios of coalbed methane (CBM demonstrate diagnostic changes that systematically vary with production and desorption times. These shifts can provide decisive, predictive information on the behaviour and potential performance of CBM operations. Samples from producing CBM wells show a general depletion in 13C-methane with increasing production times and corresponding shifts in δ13C-CH4 up to 35.8‰. Samples from canister desorption experiments show mostly enrichment in 13C for methane with increasing desorption time and isotope shifts of up to 43.4‰. Also, 13C-depletion was observed in some samples with isotope shifts of up to 32.1‰. Overall, the magnitudes of the observed isotope shifts vary considerably between different sample sets, but also within samples from the same source. The δ13C-CH4 values do not have the anticipated signature of methane generated from coal. This indicates that secondary processes, including desorption and diffusion, can influence the values. It is also challenging to deconvolute these various secondary processes because their molecular and isotope effects can have similar directions and/or magnitudes. In some instances, significant alteration of CBM gases has to be considered as a combination of secondary alteration effects.

  2. Thermal infrared remote sensing for riverscape analysis of water temperature heterogeneity: current research and future directions

    Science.gov (United States)

    Dugdale, S.; Hannah, D. M.; Malcolm, I.; Bergeron, N.; St-Hilaire, A.

    2016-12-01

    Climate change will increase summer water temperatures in northern latitude rivers. It is likely that this will have a negative impact on fish species such as salmonids, which are sensitive to elevated temperatures. Salmonids currently avoid heat stress by opportunistically using cool water zones that arise from the spatio-temporal mosaic of thermal habitats present within rivers. However, there is a general lack of information about the processes driving this thermal habitat heterogeneity or how these spatio-temporal patterns might vary under climate change. In this paper, we document how thermal infrared imaging has previously been used to better understand the processes driving river temperature patterns. We then identify key knowledge gaps that this technology can help to address in the future. First, we demonstrate how repeat thermal imagery has revealed the role of short-term hydrometeorological variability in influencing longitudinal river temperature patterns, showing that precipitation depth is strongly correlated with the degree of longitudinal temperature heterogeneity. Second, we document how thermal infrared imagery of a large watershed in Eastern Canada has shed new light on the landscape processes driving the spatial distribution of cool water patches, revealing that the distribution of cool patches is strongly linked to channel confinement, channel curvature and the proximity of dry tributary valleys. Finally, we detail gaps in current understanding of spatio-temporal patterns of river temperature heterogeneity. We explain how advances in unmanned aerial vehicle technology and deterministic temperature modelling will be combined to address these current limitations, shedding new light on the landscape processes driving geographical variability in patterns of river temperature heterogeneity. We then detail how such advances will help to identify rivers that will be resilient to future climatic warming, improving current and future strategies for

  3. Simulation of Thermal Neutron Transport Processes Directly from the Evaluated Nuclear Data Files

    Science.gov (United States)

    Androsenko, P. A.; Malkov, M. R.

    The main idea of the method proposed in this paper is to directly extract thetrequired information for Monte-Carlo calculations from nuclear data files. The met od being developed allows to directly utilize the data obtained from libraries and seehs to be the most accurate technique. Direct simulation of neutron scattering in themmal energy range using file 7 ENDF-6 format in terms of code system BRAND has beer achieved. Simulation algorithms have been verified using the criterion x2

  4. Desorption of H atoms from graphite (0001) using XUV free electron laser pulses

    DEFF Research Database (Denmark)

    Siemer, B.; Olsen, Thomas; Hoger, T.

    2010-01-01

    The desorption of neutral H atoms from graphite with femtosecond XUV pulses is reported. The velocity distribution of the atoms peaks at extremely low kinetic energies. A DFT-based electron scattering calculation traces this distribution to desorption out of specific adsorption sites on graphite......, and identifies the highest vibrational state in the adsorbate potential as a major source for the slow atoms. It is evident that multiple electron scattering processes are required for this desorption. A direct electronic excitation of a repulsive hydrogen-carbon bond seems not to be important....

  5. Repeated Thermal Stress, Shading, and Directional Selection in the Florida Reef Tract

    OpenAIRE

    Robert van Woesik; Kelly R. McCaffrey

    2017-01-01

    Over the last three decades reef corals have been subjected to an unprecedented frequency and intensity of thermal-stress events, which have led to extensive coral bleaching, disease, and mortality. Over the next century, the climate is predicted to drive sea-surface temperatures to even higher levels, consequently increasing the risk of mass bleaching and disease outbreaks. Yet, there is considerable temporal and spatial variation in coral bleaching and in disease prevalence. Using data coll...

  6. Direct evidence for a thermal effect of Ar+ ion bombardment in a conventional sputtering mode

    International Nuclear Information System (INIS)

    Okuyama, F.; Fujimoto, Y.

    1986-01-01

    Evidence is presented that the Ar + ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 0 C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar + ions, proving that the needle tips were melted by impacting Ar + ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment

  7. Thermomechanical Modelling of Direct-Drive Friction Welding Applying a Thermal Pseudo Mechanical Model for the Generation of Heat

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Hattel, Jesper Henri

    2018-01-01

    In the present work a 2D a xisymmetric thermomechanical model of the direct-drive friction welding process is developed, taking the temperature dependent shear yield stress into account in the description of the heat generation, utilizing a recent thermal pseudo mechanical model originally...... developed for the friction stir welding (FSW) process. The model is implemented in ABAQUS/Explicit via a subroutine. The application in this case is joining of austenitic stainless steel rods with an outer diameter of 112 mm, used for manufacturing of exhaust gas valves for large two stroke marine engines....... The material properties in terms of the temperature dependent flowstress curves used both in the thermal and the mechanical constitutive description are extracted from compression tests performed between 20 °C and 1200 °C on a Gleeble 1500 thermomechanical simulator. Comparison between measured and simulated...

  8. High efficiency direct thermal to electric energy conversion from radioisotope decay using selective emitters and spectrally tuned solar cells

    Science.gov (United States)

    Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

    1993-01-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.

  9. High efficiency direct thermal to electric energy conversion from radioisotope decay using selective emitters and spectrally tuned solar cells

    International Nuclear Information System (INIS)

    Chubb, D.L.; Flood, D.J.; Lowe, R.A.

    1993-08-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source

  10. Design and Construction of Experiment for Direct Electron Irradiation of Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakho [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-10-01

    Argonne is assisting SHINE Medical Technologies in developing SHINE, a system for producing fission-product 99Mo using a D/T-accelerator to produce fission in a non-critical target solution of aqueous uranyl sulfate. We have developed an experimental setup for studying thermal-hydraulics and bubble formation in the uranyl sulfate solution to simulate conditions expected in the SHINE target solution during irradiation. A direct electron beam from the linac accelerator will be used to irradiate a 20 L solution (sector of the solution vessel). Because the solution will undergo radiolytic decomposition, we will be able to study bubble formation and dynamics and effects of convection and temperature on bubble behavior. These experiments will serve as a verification/ validation tool for the thermal-hydraulic model. Utilization of the direct electron beam for irradiation allows homogeneous heating of a large solution volume and simplifies observation of the bubble dynamics simultaneously with thermal-hydraulic data collection, which will complement data collected during operation of the miniSHINE experiment. Irradiation will be conducted using a 30-40 MeV electron beam from the high-power linac accelerator. The total electron-beam power will be 20 kW, which will yield a power density on the order of 1 kW/L. The solution volume will be cooled on the front and back surfaces and central tube to mimic the geometry of the proposed SHINE solution vessel. Also, multiple thermocouples will be inserted into the solution vessel to map thermal profiles. The experimental design is now complete, and installation and testing are in progress.

  11. Modelling of discrete TDS-spectrum of hydrogen desorption

    Science.gov (United States)

    Rodchenkova, Natalia I.; Zaika, Yury V.

    2015-12-01

    High concentration of hydrogen in metal leads to hydrogen embrittlement. One of the methods to evaluate the hydrogen content is the method of thermal desorption spectroscopy (TDS). As the sample is heated under vacuumization, atomic hydrogen diffuses inside the bulk and is desorbed from the surface in the molecular form. The extraction curve (measured by a mass-spectrometric analyzer) is recorded. In experiments with monotonous external heating it is observed that background hydrogen fluxes from the extractor walls and fluxes from the sample cannot be reliably distinguished. Thus, the extraction curve is doubtful. Therefore, in this case experimenters use discrete TDS-spectrum: the sample is removed from the analytical part of the device for the specified time interval, and external temperature is then increased stepwise. The paper is devoted to the mathematical modelling and simulation of experimental studies. In the corresponding boundary-value problem with nonlinear dynamic boundary conditions physical- chemical processes in the bulk and on the surface are taken into account: heating of the sample, diffusion in the bulk, hydrogen capture by defects, penetration from the bulk to the surface and desorption. The model aimed to analyze the dynamics of hydrogen concentrations without preliminary artificial sample saturation. Numerical modelling allows to choose the point on the extraction curve that corresponds to the initial quantity of the surface hydrogen, to estimate the values of the activation energies of diffusion, desorption, parameters of reversible capture and hydride phase decomposition.

  12. Modelling of discrete TDS-spectrum of hydrogen desorption

    International Nuclear Information System (INIS)

    Rodchenkova, Natalia I; Zaika, Yury V

    2015-01-01

    High concentration of hydrogen in metal leads to hydrogen embrittlement. One of the methods to evaluate the hydrogen content is the method of thermal desorption spectroscopy (TDS). As the sample is heated under vacuumization, atomic hydrogen diffuses inside the bulk and is desorbed from the surface in the molecular form. The extraction curve (measured by a mass-spectrometric analyzer) is recorded. In experiments with monotonous external heating it is observed that background hydrogen fluxes from the extractor walls and fluxes from the sample cannot be reliably distinguished. Thus, the extraction curve is doubtful. Therefore, in this case experimenters use discrete TDS-spectrum: the sample is removed from the analytical part of the device for the specified time interval, and external temperature is then increased stepwise. The paper is devoted to the mathematical modelling and simulation of experimental studies. In the corresponding boundary-value problem with nonlinear dynamic boundary conditions physical- chemical processes in the bulk and on the surface are taken into account: heating of the sample, diffusion in the bulk, hydrogen capture by defects, penetration from the bulk to the surface and desorption. The model aimed to analyze the dynamics of hydrogen concentrations without preliminary artificial sample saturation. Numerical modelling allows to choose the point on the extraction curve that corresponds to the initial quantity of the surface hydrogen, to estimate the values of the activation energies of diffusion, desorption, parameters of reversible capture and hydride phase decomposition. (paper)

  13. Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability

    Science.gov (United States)

    Grimm, R. E.; Marchi, S.

    2018-03-01

    Intense bombardment is considered characteristic of the Hadean and early Archean eons, yet some detrital zircons indicate that near-surface water was present and thus at least intervals of clement conditions may have existed. We investigate the habitability of the top few kilometers of the subsurface by updating a prior approach to thermal evolution of the crust due to impact heating, using a revised bombardment history, a more accurate thermal model, and treatment of melt sheets from large projectiles (>100 km diameter). We find that subsurface habitable volume grows nearly continuously throughout the Hadean and early Archean (4.5-3.5 Ga) because impact heat is dissipated rapidly compared to the total duration and waning strength of the bombardment. Global sterilization was only achieved using an order of magnitude more projectiles in 1/10 the time. Melt sheets from large projectiles can completely resurface the Earth several times prior to ∼4.2 Ga but at most once since then. Even in the Hadean, melt sheets have little effect on habitability because cooling times are short compared to resurfacing intervals, allowing subsurface biospheres to be locally re-established by groundwater infiltration between major impacts. Therefore the subsurface is always habitable somewhere, and production of global steam or silicate-vapor atmospheres are the only remaining avenues to early surface sterilization by bombardment.

  14. Segregation of O2 and CO on the surface of dust grains determines the desorption energy of O2

    Science.gov (United States)

    Noble, J. A.; Diana, S.; Dulieu, F.

    2015-12-01

    Selective depletion towards pre-stellar cores is still not understood. The exchange between the solid and gas phases is central to this mystery. The aim of this paper is to show that the thermal desorption of O2 and CO from a submonolayer mixture is greatly affected by the composition of the initial surface population. We have performed thermally programmed desorption (TPD) experiments on various submonolayer mixtures of O2 and CO. Pure O2 and CO exhibit almost the same desorption behaviour, but their desorption differs strongly when mixed. Pure O2 is slightly less volatile than CO, while in mixtures, O2 desorbs earlier than CO. We analyse our data using a desorption law linking competition for binding sites with desorption, based on the assumption that the binding energy distribution of both molecules is the same. We apply Fermi-Dirac statistics in order to calculate the adsorption site population distribution, and derive the desorbing fluxes. Despite its simplicity, the model reproduces the observed desorption profiles, indicating that competition for adsorption sites is the reason for lower temperature O2 desorption. CO molecules push-out or `dislodge' O2 molecules from the most favourable binding sites, ultimately forcing their early desorption. It is crucial to consider the surface coverage of dust grains in any description of desorption. Competition for access to binding sites results in some important discrepancies between similar kinds of molecules, such as CO and O2. This is an important phenomenon to be investigated in order to develop a better understanding of the apparently selective depletion observed in dark molecular clouds.

  15. Thermal radiation characteristics and direct evidence of tungsten cooling on the way to nanostructure formation on its surface

    Energy Technology Data Exchange (ETDEWEB)

    Takamura, S., E-mail: takamura@aitech.ac.jp [Faculty of Engineering, Aichi Institute of Technology, Yakusa-cho, Toyota 470-0392 (Japan); Miyamoto, T. [Faculty of Engineering, Aichi Institute of Technology, Yakusa-cho, Toyota 470-0392 (Japan); Ohno, N. [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2013-07-15

    The physical properties of tungsten with nanostructure on its surface are investigated focusing on the thermal radiation and cooling characteristics. First, direct evidence of substantial W surface cooling has been clearly shown with use of a very thin thermocouple inserted into W target, which solves an uncertainty associated with a radiation thermometer. Second, the above measurements of W surface temperature make it possible to estimate quantitatively the total emissivity from which we may evaluate the radiative power through the Stefan–Boltzmann equation, which is very important for mitigation evaluation of a serious plasma heat load to the plasma-facing component.

  16. Thermal radiation characteristics and direct evidence of tungsten cooling on the way to nanostructure formation on its surface

    International Nuclear Information System (INIS)

    Takamura, S.; Miyamoto, T.; Ohno, N.

    2013-01-01

    The physical properties of tungsten with nanostructure on its surface are investigated focusing on the thermal radiation and cooling characteristics. First, direct evidence of substantial W surface cooling has been clearly shown with use of a very thin thermocouple inserted into W target, which solves an uncertainty associated with a radiation thermometer. Second, the above measurements of W surface temperature make it possible to estimate quantitatively the total emissivity from which we may evaluate the radiative power through the Stefan–Boltzmann equation, which is very important for mitigation evaluation of a serious plasma heat load to the plasma-facing component

  17. Design and modelling of an innovative three-stage thermal storage system for direct steam generation CSP plants

    Science.gov (United States)

    Garcia, Pierre; Vuillerme, Valéry; Olcese, Marco; El Mourchid, Nadim

    2016-05-01

    Thermal Energy Storage systems (TES) for a Direct Steam Generation (DSG) solar plant feature preferably three stages in series including a latent heat storage module so that steam can be recovered with a limited temperature loss. The storage system designed within the Alsolen Sup project is characterized by an innovative combination of sensible and latent modules. A dynamic model of this three-stage storage has been developed and applied to size the storage system of the Alsolen Sup® plant demonstrator at CEA Cadarache. Results of this simulation show that this promising concept is an efficient way to store heat in DSG solar plants.

  18. Gas desorption during friction of amorphous carbon films

    International Nuclear Information System (INIS)

    Rusanov, A; Fontaine, J; Martin, J-M; Mogne, T L; Nevshupa, R

    2008-01-01

    Gas desorption induced by friction of solids, i.e. tribodesorption, is one of the numerous physical and chemical phenomena, which arise during friction as result of thermal and structural activation of material in a friction zone. Tribodesorption of carbon oxides, hydrocarbons, and water vapours may lead to significant deterioration of ultra high vacuum conditions in modern technological equipment in electronic, optoelectronic industries. Therefore, knowledge of tribodesorption is crucial for the performance and lifetime of vacuum tribosystems. Diamond-like carbon (DLC) coatings are interesting materials for vacuum tribological systems due to their high wear resistance and low friction. Highly hydrogenated amorphous carbon (a-C:H) films are known to exhibit extremely low friction coefficient under high vacuum or inert environment, known as 'superlubricity' or 'superlow friction'. However, the superlow friction period is not always stable and then tends to spontaneous transition to high friction. It is supposed that hydrogen supply from the bulk to the surface is crucial for establishing and maintaining superlow friction. Thus, tribodesorption can serve also as a new technique to determine the role of gases in superlow friction mechanisms. Desorption of various a-C:H films, deposited by PECVD, ion-beam deposition and deposition using diode system, has been studied by means of ultra-high vacuum tribometer equipped with a mass spectrometer. It was found that in superlow friction period desorption rate was below the detection limit in the 0-85 mass range. However, transition from superlow friction to high friction was accompanied by desorption of various gases, mainly of H 2 and CH 4 . During friction transition, surfaces were heavily damaged. In experiments with DLC films with low hydrogen content tribodesorption was significant during the whole experiment, while low friction was not observed. From estimation of maximum surface temperature during sliding contact it

  19. MoO3 Thickness, Thermal Annealing and Solvent Annealing Effects on Inverted and Direct Polymer Photovoltaic Solar Cells

    Directory of Open Access Journals (Sweden)

    Guillaume Wantz

    2012-11-01

    Full Text Available Several parameters of the fabrication process of inverted polymer bulk heterojunction solar cells based on titanium oxide as an electron selective layer and molybdenum oxide as a hole selective layer were tested in order to achieve efficient organic photovoltaic solar cells. Thermal annealing treatment is a common process to achieve optimum morphology, but it proved to be damageable for the performance of this kind of inverted solar cells. We demonstrate using Auger analysis combined with argon etching that diffusion of species occurs from the MoO3/Ag top layers into the active layer upon thermal annealing. In order to achieve efficient devices, the morphology of the bulk heterojunction was then manipulated using the solvent annealing technique as an alternative to thermal annealing. The influence of the MoO3 thickness was studied on inverted, as well as direct, structure. It appeared that only 1 nm-thick MoO3 is enough to exhibit highly efficient devices (PCE = 3.8% and that increasing the thickness up to 15 nm does not change the device performance. 

  20. One-step fabrication of submicrostructures by low one-photon absorption direct laser writing technique with local thermal effect

    Science.gov (United States)

    Nguyen, Dam Thuy Trang; Tong, Quang Cong; Ledoux-Rak, Isabelle; Lai, Ngoc Diep

    2016-01-01

    In this work, local thermal effect induced by a continuous-wave laser has been investigated and exploited to optimize the low one-photon absorption (LOPA) direct laser writing (DLW) technique for fabrication of polymer-based microstructures. It was demonstrated that the temperature of excited SU8 photoresist at the focusing area increases to above 100 °C due to high excitation intensity and becomes stable at that temperature thanks to the use of a continuous-wave laser at 532 nm-wavelength. This optically induced thermal effect immediately completes the crosslinking process at the photopolymerized region, allowing obtain desired structures without using the conventional post-exposure bake (PEB) step, which is usually realized after the exposure. Theoretical calculation of the temperature distribution induced by local optical excitation using finite element method confirmed the experimental results. LOPA-based DLW technique combined with optically induced thermal effect (local PEB) shows great advantages over the traditional PEB, such as simple, short fabrication time, high resolution. In particular, it allowed the overcoming of the accumulation effect inherently existed in optical lithography by one-photon absorption process, resulting in small and uniform structures with very short lattice constant.

  1. Effects of an electron beam on adsorption and desorption of ammonia on ruthenium (0001)

    International Nuclear Information System (INIS)

    Danielson, L.R.; Dresser, M.J.; Donaldson, E.E.; Sandstrom, D.R.

    1978-01-01

    The effects of an electron beam on ammonia adsorption and desorption on Ru(0001) have been investigated by Auger electron spectroscopy, low-energy electron diffraction, and thermal flash desorption. Appreciable adsorption at room temperature occurred only on the area of the Ru crystal which had been bombarded by an electron beam during dosing. The adsorption rate was a function of beam current density and ammonia pressure, and an apparent (2x2) diffraction pattern appeared in the area bombarded by the electron beam. Electron bombardment of the molecular γ states of ammonia followed by flash desorption showed that less ammonia and more hydrogen and nitrogen were desorbed as the bombardment time increased. An analysis of this process based on electron-induced dissociation of the ammonia molecule yielded an effective initial dissociation cross section of 3x10 -6 cm 2 . Hydrogen flash desorption spectra after bombardment of the γ states obeying first order kinetics with desorption energies of 0.78 and 1.0 eV. Electron bombardment of the γ states for short times produced the same effects on the ammonia flash desorption spectra as preadsorption of hydrogen. (Auth.)

  2. Direct Iron Coating onto Nd-Fe-B Powder by Thermal Decomposition of Iron Pentacarbonyl

    International Nuclear Information System (INIS)

    Yamamuro, S; Okano, M; Tanaka, T; Sumiyama, K; Nozawa, N; Nishiuchi, T; Hirosawa, S; Ohkubo, T

    2011-01-01

    Iron-coated Nd-Fe-B composite powder was prepared by thermal decomposition of iron pentacarbonyl in an inert organic solvent in the presence of alkylamine. Though this method is based on a modified solution-phase process to synthesize highly size-controlled iron nanoparticles, it is in turn featured by a suppressed formation of iron nanoparticles to achieve an efficient iron coating solely onto the surfaces of rare-earth magnet powder. The Nd-Fe-B magnetic powder was successfully coated by iron shells whose thicknesses were of the order of submicrometer to micrometer, being tuneable by the amount of initially loaded iron pentacarbonyl in a reaction flask. The amount of the coated iron reached to more than 10 wt.% of the initial Nd-Fe-B magnetic powder, which is practically sufficient to fabricate Nd-Fe-B/α-Fe nanocomposite permanent magnets.

  3. Direct Observation of the Phenomenology of a Solid Thermal Explosion Using Time-Resolved Proton Radiography

    International Nuclear Information System (INIS)

    Smilowitz, L.; Henson, B. F.; Romero, J. J.; Asay, B. W.; Schwartz, C. L.; Saunders, A.; Merrill, F. E.; Morris, C. L.; Kwiatkowski, K.; Hogan, G.; Nedrow, P.; Murray, M. M.; Thompson, T. N.; McNeil, W.; Rightley, P.; Marr-Lyon, M.

    2008-01-01

    We present a new phenomenology for burn propagation inside a thermal explosion based on dynamic radiography. Radiographic images were obtained of an aluminum cased solid cylindrical sample of a plastic bonded formulation of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. The phenomenology observed is ignition followed by cracking in the solid accompanied by the propagation of a radially symmetric front of increasing proton transmission. This is followed by a further increase in transmission through the sample, ending after approximately 100 μs. We show that these processes are consistent with the propagation of a convective burn front followed by consumption of the remaining solid by conductive particle burning

  4. Preparation of uranium dioxide by thermal decomposition and direct reduction of ammonium uranate

    International Nuclear Information System (INIS)

    Hernandez R, R.

    1995-01-01

    The thermal decomposition of ammonium uranate has been studied by infrared spectroscopy, and X-ray diffraction. It has been show that ammonia remains in the solid until substantially 350 Centigrade degrees, when gaseous nitrogen is released. It is concluded that compounds derived from the calcination of ammonium uranate at atmospheric pressure, produced amorphous U O 3 at about 350-400 Centigrade degrees and transform to U 3 O 8 via α - U O 3 and/or α - U O 3 . The object of this study was to obtain reliable fundamental information regarding the character of the pure carbon monoxide-ammonium uranate-uranium trioxide-uranium octaoxide reaction, in the range of temperatures that has been used in commercial reduction processes. Through the use of high-purity samples and by the proper control of incidental variable, this object was realized. (Author)

  5. Film growth, adsorption and desorption kinetics of indigo on SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Scherwitzl, Boris, E-mail: b.scherwitzl@tugraz.at; Resel, Roland; Winkler, Adolf [Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

    2014-05-14

    Organic dyes have recently been discovered as promising semiconducting materials, attributable to the formation of hydrogen bonds. In this work, the adsorption and desorption behavior, as well as thin film growth was studied in detail for indigo molecules on silicon dioxide with different substrate treatments. The material was evaporated onto the substrate by means of physical vapor deposition under ultra-high vacuum conditions and was subsequently studied by Thermal Desorption Spectroscopy (TDS), Auger Electron Spectroscopy, X-Ray Diffraction, and Atomic Force Microscopy. TDS revealed initially adsorbed molecules to be strongly bonded on a sputter cleaned surface. After further deposition a formation of dimers is suggested, which de-stabilizes the bonding mechanism to the substrate and leads to a weakly bonded adsorbate. The dimers are highly mobile on the surface until they get incorporated into energetically favourable three-dimensional islands in a dewetting process. The stronger bonding of molecules within those islands could be shown by a higher desorption temperature. On a carbon contaminated surface no strongly bonded molecules appeared initially, weakly bonded monomers rather rearrange into islands at a surface coverage that is equivalent to one third of a monolayer of flat-lying molecules. The sticking coefficient was found to be unity on both substrates. The desorption energies from carbon covered silicon dioxide calculated to 1.67 ± 0.05 eV for multilayer desorption from the islands and 0.84 ± 0.05 eV for monolayer desorption. Corresponding values for desorption from a sputter cleaned surface are 1.53 ± 0.05 eV for multilayer and 0.83 ± 0.05 eV for monolayer desorption.

  6. Enhanced desorption of cesium from collapsed interlayer regions in vermiculite by hydrothermal treatment with divalent cations

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xiangbiao, E-mail: yin.x.aa@m.titech.ac.jp [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Wang, Xinpeng [College of Resources and Metallurgy, Guangxi University, 100 Daxue East Road, Nanning 530004 (China); Wu, Hao; Ohnuki, Toshihiko; Takeshita, Kenji [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2017-03-15

    Highlights: • Desorption of Cs{sup +} fixed in collapsed interlayer region of vermiculite was studied. • Monovalent cations readily induced interlayer collapse inhibiting Cs{sup +} desorption. • Larger hydrous ionic radii of divalent cations greatly prevented Cs{sup +} desorption. • Effect of divalent cation on Cs{sup +} desorption changes depending on thermal treatment. • ∼100% removal of saturated Cs{sup +} was achieved by hydrothermal treatment at 250 °C. - Abstract: Adsorption of cesium (Cs) on phyllosilicates has been intensively investigated because natural soils have strong ability of immobilizing Cs within clay minerals resulting in difficulty of decontamination. The objectives of present study are to clarify how Cs fixation on vermiculite is influenced by structure change caused by Cs sorption at different loading levels and how Cs desorption is affected by various replacing cations induced at different treating temperature. As a result, more than 80% of Cs was readily desorbed from vermiculite with loading amount of 2% saturated Cs (5.49 × 10{sup −3} mmol g{sup −1}) after four cycles of treatment of 0.01 M Mg{sup 2+}/Ca{sup 2+} at room temperature, but less than 20% of Cs was desorbed from saturated vermiculite. These distinct desorption patterns were attributed to inhibition of Cs desorption by interlayer collapse of vermiculite, especially at high Cs loadings. In contrast, elevated temperature significantly facilitated divalent cations to efficiently desorb Cs from collapsed regions. After five cycles of treatment at 250 °C with 0.01 M Mg{sup 2+}, ∼100% removal of saturated Cs was achieved. X-ray diffraction analysis results suggested that Cs desorption was completed through enhanced diffusion of Mg{sup 2+} cations into collapsed interlayer space under hydrothermal condition resulting in subsequent interlayer decollapse and readily release of Cs{sup +}.

  7. From the direct numerical simulation to system codes-perspective for the multi-scale analysis of LWR thermal hydraulics

    International Nuclear Information System (INIS)

    Bestion, D.

    2010-01-01

    A multi-scale analysis of water-cooled reactor thermal hydraulics can be used to take advantage of increased computer power and improved simulation tools, including Direct Numerical Simulation (DNS), Computational Fluid Dynamics (CFD) (in both open and porous mediums), and system thermalhydraulic codes. This paper presents a general strategy for this procedure for various thermalhydraulic scales. A short state of the art is given for each scale, and the role of the scale in the overall multi-scale analysis process is defined. System thermalhydraulic codes will remain a privileged tool for many investigations related to safety. CFD in porous medium is already being frequently used for core thermal hydraulics, either in 3D modules of system codes or in component codes. CFD in open medium allows zooming on some reactor components in specific situations, and may be coupled to the system and component scales. Various modeling approaches exist in the domain from DNS to CFD which may be used to improve the understanding of flow processes, and as a basis for developing more physically based models for macroscopic tools. A few examples are given to illustrate the multi-scale approach. Perspectives for the future are drawn from the present state of the art and directions for future research and development are given

  8. Reusable bi-directional 3ω sensor to measure thermal conductivity of 100-μm thick biological tissues

    Science.gov (United States)

    Lubner, Sean D.; Choi, Jeunghwan; Wehmeyer, Geoff; Waag, Bastian; Mishra, Vivek; Natesan, Harishankar; Bischof, John C.; Dames, Chris

    2015-01-01

    Accurate knowledge of the thermal conductivity (k) of biological tissues is important for cryopreservation, thermal ablation, and cryosurgery. Here, we adapt the 3ω method—widely used for rigid, inorganic solids—as a reusable sensor to measure k of soft biological samples two orders of magnitude thinner than conventional tissue characterization methods. Analytical and numerical studies quantify the error of the commonly used "boundary mismatch approximation" of the bi-directional 3ω geometry, confirm that the generalized slope method is exact in the low-frequency limit, and bound its error for finite frequencies. The bi-directional 3ω measurement device is validated using control experiments to within ±2% (liquid water, standard deviation) and ±5% (ice). Measurements of mouse liver cover a temperature ranging from -69 °C to +33 °C. The liver results are independent of sample thicknesses from 3 mm down to 100 μm and agree with available literature for non-mouse liver to within the measurement scatter.

  9. Assessment Of The Viability Of Kaduna City Climate For Year Round Use Of Direct Solar Thermal Cooking Fuel In Housing

    Directory of Open Access Journals (Sweden)

    Boumann Ephraim Sule

    2017-10-01

    Full Text Available Solar energy obtained from the sun is the world most abundant and cheapest source of energy as a cooking fuel. It comes in two forms Concentrated Solar Thermal direct conversion of solar energy to heat that cooks and Solar Photovoltaic PV a conversion of solar energy to electrical then to heat energy the former technology is simple and far cheaper. Despite all these architectural and engineering researches is yet to capture it for indoor cooking because of inability to cook year round due the claimed hindrances by weather condition such as clouds rainfall wind dusty atmosphere and many others. This paper attempted to look into the possibility of cooking year round in Kaduna city. It collected and analyzed ten years climatic data from three different meteorological stations strategically located round the city this showed a low solar radiation in the month of August. It further compared the result with a literature review of solar cooking carried in the same month the findings showed at the peak of each weather hindrance a another element overrides it to give enough minimum energy for cooking a meals. This paper has therefore pointed the potentials of Kaduna city climate for year round use of concentrated solar thermal as a cooking fuel in residential building and further recommends the architectural collaboration with engineers for the direct capturing of solar rays into residential dwelling as a sustainable cooking fuel.

  10. Thermal analysis of a direct evaporative cooling system enhancement with desiccant dehumidification for vehicular air conditioning

    International Nuclear Information System (INIS)

    Alahmer, Ali

    2016-01-01

    Highlights: • Thermal analysis was conducted to design a desiccant evaporative cooling system for vehicular air conditioning. • EC is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter. • Drawbacks of evaporative cooler of increased weight and reduced COP. • A rotary desiccant dehumidifier with generation was combined with evaporative cooling to be more efficient. - Abstract: This manuscript analyzes the sub-systems of evaporative cooler (EC) combined with desiccant dehumidification and regeneration for automotive air conditioning purpose. The thermodynamic and psychometric analysis was conducted to design all evaporative cooling system components in terms of desiccant selection, regeneration process, compact heat exchanger and evaporative cooler. Moreover, the effect of the desiccant, heat exchanger and evaporative performances on the mass flow rate and water sprayed required for evaporative cooling system was investigated. The results show that the theoretical evaporative cooling design will achieve two main objectives: lower fuel consumption and less environmental pollutants. However, it has the two drawbacks in terms of increased weight and reduces the coefficient of performance (COP). The main remark is that evaporating cooling system is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter.

  11. In situ sonochemical reduction and direct functionalization of graphene oxide: A robust approach with thermal and biomedical applications.

    Science.gov (United States)

    Maktedar, Shrikant S; Mehetre, Shantilal S; Avashthi, Gopal; Singh, Man

    2017-01-01

    The rapid, robust, scalable and non-hazardous sonochemical approach for in situ reduction and direct functionalization of graphene oxide has been developed for non-toxic biomedical applications. The graphene oxide (GrO) was directly functionalized with tryptamine (TA) without using any hazardous acylating and coupling reagents. The reaction was completed within 20min. An impact of ultrasound was inferred for a direct functionalization with other conventional methods. The evolved electronic states were confirmed with near edge X-ray absorption fine structure (NEXAFS). The direct covalent functionalization and formation of f-(TA) GrO was proven with FTIR, 13 C solid state NMR, XPS, XRD, Raman' HRTEM, AFM and TGA. The total percentage weight loss in TGA confirms an enhanced thermal stability of f-(TA) GrO. The f-(TA) GrO was further explored for an investigation of in vitro antimicrobial activity to ensure the health and environmental safety. An outstanding antibacterial activity of f-(TA) GrO was found against gram positive Staphylococcus aureus at MIC 128mgmL -1 . It confirms a suitability of f-(TA) GrO for thermally stable antibacterial coating. The f-(TA) GrO showed 39.14-48.9% antioxidant activities, evaluated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. The inherent cytotoxicity of f-(TA) GrO was evaluated with SRB assay to living cells, MCF-7 and Vero. The estimated cell viabilities were >80% upon addition of f-(TA) GrO over a wide concentration range of 10-80μgmL -1 . The high cytocompatibility of f-(TA) GrO confirms the low toxicity and an excellent biocompatibility. The morphological effect on Vero cell line, evidently confirmed the biocompatibility of f-(TA) GrO. Therefore, f-(TA) GrO was emerged as an advanced functional biomaterial for thermal and biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Directional anisotropy in thermal infrared measurements over Toulouse city centre during the CAPITOUL measurement campaigns: first results

    Science.gov (United States)

    Lagouarde, J.-P.; Irvine, M.

    2008-12-01

    The measurements of surface temperature are prone to important directional anisotropy related to the structure of the canopy and the radiative and energy exchanges inside of it. Directional effects must be taken into account for a number of practical applications such as the correction of large swath satellite data, the assimilation of thermal infrared (TIR) measurements in surface models, the design of future spatial missions… For urban canopies, experimental measurements of TIR directional anisotropy previously performed during summer days over Marseille in the framework of the ESCOMPTE campaign (2001) revealed significant angular surface temperature variations with noticeable hot spot effects whose intensity was related to the canopy structure. The CAPITOUL project ( http://medias.cnrs.fr/capitoul/ ) provided the opportunity to extend these results to other seasons and to nighttime conditions. The experimental setup is based on the use of 2 airborne TIR cameras with different lenses, inclination and resolution, and installed aboard a small aircraft. The flight protocol allowed the retrieval of directional anisotropy in all azimutal directions and in a range of zenith viewing angles between nadir and 62°. Measurements were performed during several intensive operation periods (IOP) in summer (2004 july), autumn (2004 September and October) and winter (2005 February). Only the first results of the 2004 autumn and 2005 winter IOPs are presented in this paper. The results obtained in daytime conditions confirm the systematic hot spot effects observed in previous experiments over cities. The variations found seem to be particularly important in winter when sun elevation is low: for instance they range between -4 and 10 K between oblique and nadir viewing in February. During nighttime conditions, angular variations are much lower (always less than 2 K between nadir and 60° zenithal viewing angle), whichever the azimutal viewing direction.

  13. Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

    Science.gov (United States)

    Idelevich, Evgeny A.; Grünastel, Barbara

    2016-01-01

    ABSTRACT Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption–ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. PMID:27795344

  14. Performance analysis of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

    International Nuclear Information System (INIS)

    Modi, Anish; Haglind, Fredrik

    2014-01-01

    Solar thermal power plants have attracted increasing interest in the past few years – with respect to both the design of the various plant components, and extending the operation hours by employing different types of storage systems. One approach to improve the overall plant efficiency is to use direct steam generation with water/steam as both the heat transfer fluid in the solar receivers and the cycle working fluid. This enables operating the plant with higher turbine inlet temperatures. Available literature suggests that it is feasible to use ammonia-water mixtures at high temperatures without corroding the equipment by using suitable additives with the mixture. The purpose of the study reported here was to investigate if there is any benefit of using a Kalina cycle for a direct steam generation, central receiver solar thermal power plant with high live steam temperature (450 °C) and pressure (over 100 bar). Thermodynamic performance of the Kalina cycle in terms of the plant exergy efficiency was evaluated and compared with a simple Rankine cycle. The rates of exergy destruction for the different components in the two cycles were also calculated and compared. The results suggest that the simple Rankine cycle exhibits better performance than the Kalina cycle when the heat input is only from the solar receiver. However, when using a two-tank molten-salt storage system as the primary source of heat input, the Kalina cycle showed an advantage over the simple Rankine cycle because of about 33 % reduction in the storage requirement. The solar receiver showed the highest rate of exergy destruction for both the cycles. The rates of exergy destruction in other components of the cycles were found to be highly dependent on the amount of recuperation, and the ammonia mass fraction and pressure at the turbine inlet. - Highlights: •Kalina cycle for a central receiver solar thermal power plant with direct steam generation. •Rankine cycle shows better plant exergy

  15. Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Bismarck L., E-mail: bismarck_luiz@yahoo.com.br [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, 13083-860 Campinas, SP (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil)

    2016-04-15

    Low temperature soldering technology encompasses Sn–Bi based alloys as reference materials for joints since such alloys may be molten at temperatures less than 180 °C. Despite the relatively high strength of these alloys, segregation problems and low ductility are recognized as potential disadvantages. Thus, for low-temperature applications, Bi–Sn eutectic or near-eutectic compositions with or without additions of alloying elements are considered interesting possibilities. In this context, additions of third elements such as Cu and Ag may be an alternative in order to reach sounder solder joints. The length scale of the phases and their proportions are known to be the most important factors affecting the final wear, mechanical and corrosions properties of ternary Sn–Bi–(Cu,Ag) alloys. In spite of this promising outlook, studies emphasizing interrelations of microstructure features and solidification thermal parameters regarding these multicomponent alloys are rare in the literature. In the present investigation Sn–Bi–(Cu,Ag) alloys were directionally solidified (DS) under transient heat flow conditions. A complete characterization is performed including experimental cooling thermal parameters, segregation (XRF), optical and scanning electron microscopies, X-ray diffraction (XRD) and length scale of the microstructural phases. Experimental growth laws relating dendritic spacings to solidification thermal parameters have been proposed with emphasis on the effects of Ag and Cu. The theoretical predictions of the Rappaz-Boettinger model are shown to be slightly above the experimental scatter of secondary dendritic arm spacings for both ternary Sn–Bi–Cu and Sn–Bi–Ag alloys examined. - Highlights: • Dendritic growth prevailed for the ternary Sn–Bi–Cu and Sn–Bi–Ag solder alloys. • Bi precipitates within Sn-rich dendrites were shown to be unevenly distributed. • Morphology and preferential region for the Ag{sub 3}Sn growth depend on Ag

  16. Indirect and direct measurement of thermal neutron acceleration by inelastic scattering on the {sup 177}Lu isomer

    Energy Technology Data Exchange (ETDEWEB)

    Belier, G.; Roig, O.; Meot, V.; Daugas, J.M. [CEA Bruyeres-le-Chatel, Dept. de Physique Theorique et Appliquee, 91 (France); Aupiais, J.; Jutier, Ch.; Le Petit, G. [CEA Bruyeres-le-Chatel, Service de Physique Nucleaire, 91 (France). Dept. de Physique Theorique et Appliquee; Letourneau, A.; Marie, F. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, Service de Physique Nucleaire, 91- Gif sur Yvette (France); Veyssiere, Ch. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, Service d' Ingenierie des Systemes, 91- Gif sur Yvette (France)

    2008-07-01

    When neutrons interact with isomers, these isomers can de-excite and in such a reaction the outgoing neutron has an energy greater than the in-going one. This process is referred as Inelastic Neutron Acceleration or Super-elastic Scattering. Up to now this process was observed for only two nucleus, {sup 152m}Eu and {sup 180m}Hf by measuring the number of fast neutrons produced by isomeric targets irradiated with thermal neutrons. In these experiments the energies of the accelerated neutrons were not measured. This report presents an indirect measurement of inelastic neutron acceleration on {sup 177m}Lu, based on the burn-up and the radiative capture cross sections measurements. Since at thermal energies the inelastic scattering and the radiative capture are the only processes that contribute to the isomer burn-up, the inelastic cross section can be deduced from the difference between the two measured quantities. Applying this method for the {sup 177}Lu isomer with different neutron fluxes we obtained a value of (257 {+-} 50) barns (for a temperature of 323 K) and determined that there is no integral resonance for this process. In addition the radiative capture cross section on {sup 177g}Lu was measured with a much better accuracy than the accepted value. Since the acceleration cross section is quite high, a direct measurement of this process was undertaken, sending thermal neutrons and measuring the fast neutrons. The main goal now is to measure the outgoing neutron energies in order to identify the neutron transitions in the exit channel. In particular the K conservation question can be addressed by such a measurement. (author)

  17. IRIS , Hinode , SDO , and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung-Sun [Hinode Science Center, National Astronomical Observatory of Japan (NAOJ), 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan); Imada, Shinsuke [Institute for Space–Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 466-8550 (Japan); Watanabe, Kyoko [National Defense Academy of Japan, 1-10-20 Hashirimizu, Yokosuka 239-8686 (Japan); Bamba, Yumi [Hinode team, ISAS/JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Brooks, David H., E-mail: ksun.lee@nao.ac.jp [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2017-02-20

    An X1.6 flare occurred in active region AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode , IRIS , SDO , and RHESSI . We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode /EIS, we measure the temporal variation of the plasma properties in the bright kernel in the chromosphere and corona. We find that explosive evaporation was observed when the WL emission occurred, even though the intensity enhancement in hotter lines is quite weak. The temporal correlation of the WL emission, HXR peak, and evaporation flows indicates that the WL emission was produced by accelerated electrons. To understand the WL emission process, we calculated the energy flux deposited by non-thermal electrons (observed by RHESSI ) and compared it to the dissipated energy estimated from a chromospheric line (Mg ii triplet) observed by IRIS . The deposited energy flux from the non-thermal electrons is about (3–7.7) × 10{sup 10} erg cm{sup −2} s{sup −1} for a given low-energy cutoff of 30–40 keV, assuming the thick-target model. The energy flux estimated from the changes in temperature in the chromosphere measured using the Mg ii subordinate line is about (4.6–6.7) × 10{sup 9} erg cm{sup −2} s{sup −1}: ∼6%–22% of the deposited energy. This comparison of estimated energy fluxes implies that the continuum enhancement was directly produced by the non-thermal electrons.

  18. On plate graphite supported sample processing for simultaneous lipid and protein identification by matrix assisted laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Calvano, Cosima Damiana; van der Werf, Inez Dorothé; Sabbatini, Luigia; Palmisano, Francesco

    2015-05-01

    The simultaneous identification of lipids and proteins by matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) after direct on-plate processing of micro-samples supported on colloidal graphite is demonstrated. Taking advantages of large surface area and thermal conductivity, graphite provided an ideal substrate for on-plate proteolysis and lipid extraction. Indeed proteins could be efficiently digested on-plate within 15 min, providing sequence coverages comparable to those obtained by conventional in-solution overnight digestion. Interestingly, detection of hydrophilic phosphorylated peptides could be easily achieved without any further enrichment step. Furthermore, lipids could be simultaneously extracted/identified without any additional treatment/processing step as demonstrated for model complex samples such as milk and egg. The present approach is simple, efficient, of large applicability and offers great promise for protein and lipid identification in very small samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Materials and design concerning magnetohydrodynamic channels of direct power conversion from combustion gases thermal energy into electricity

    International Nuclear Information System (INIS)

    Yerouchalmi, David

    1970-01-01

    Direct power conversion of thermal energy into electricity by magnetohydrodynamic is defined through thermodynamic cycles of hot gases; the present work concerning only the channel-generator operating with fossil gases in open cycle. Insulating walls and electrodes are subject initially to general apparent working conditions and those are followed by several others which appear only when experimental stage is reached. First, a choice has to be made between cold walls and hot walls which have been both closely investigated. But experience and theory lead to a third solution: viz controlled temperature walls and to consequent thermal exchange design. Many additional phenomena such as: solid state electrolysis, vaporisation, corrosion and alkali seed migration are analysed; then some solutions are described, tried and suggested. Same is given for mechanical, cooling devices, cold electric junctions and current relays. Experimental devices and work done on several solutions are described and results given. New prospects are suggested; and, in conclusion, the subject still appears to merit quite an important amount of further research. (author) [fr

  20. High temperature thermal conductivity measurements of UO/sub 2/ by Direct Electrical Heating. Final report. [MANTRA-III

    Energy Technology Data Exchange (ETDEWEB)

    Bassett, B

    1980-10-01

    High temperature properties of reactor type UO/sub 2/ pellets were measured using a Direct Electrical Heating (DEH) Facility. Modifications to the experimental apparatus have been made so that successful and reproducible DEH runs may be carried out while protecting the pellets from oxidation at high temperature. X-ray diffraction measurements on the UO/sub 2/ pellets have been made before and after runs to assure that sample oxidation has not occurred. A computer code has been developed that will model the experiment using equations that describe physical properties of the material. This code allows these equations to be checked by comparing the model results to collected data. The thermal conductivity equation for UO/sub 2/ proposed by Weilbacher has been used for this analysis. By adjusting the empirical parameters in Weilbacher's equation, experimental data can be matched by the code. From the several runs analyzed, the resulting thermal conductivity equation is lambda = 1/4.79 + 0.0247T/ + 1.06 x 10/sup -3/ exp(-1.62/kT/) - 4410. exp(-3.71/kT/) where lambda is in w/cm K, k is the Boltzman constant, and T is the temperature in Kelvin.

  1. Analysis of the thermal response of a BWR Mark-I containment shell to direct contact by molten core materials

    International Nuclear Information System (INIS)

    Kress, T.S.; Cleveland, J.C.

    1988-01-01

    This study was undertaken to evaluate the thermal response of a BWR Mark-I containment shell in the event of an accident severe enough for molten core materials to fall into the cavity beneath the rector vessel and eventually come into direct contact with the shell. An existing ORNL three-dimensional transient heat transport computer code, HEATING-6, was used for a specific 2-D case (and variations) for which representative melt/shell boundary conditions required as input were available from other studies. In addition to the use of HEATING-6, a simplified analytical steady-state correlation was developed and given the name BWR Liner Analysis Program (BWRLAP). BWRLAP was ''benchmarked'' by comparison with HEATING-6 and was then used to make a number of parametric calculations to investigate the sensitivities of the results to the inputs. 5 refs., 11 figs., 2 tabs

  2. Transient heat transfer in a directly-irradiated solar chemical reactor for the thermal dissociation of ZnO

    International Nuclear Information System (INIS)

    Mueller, R.; Lipinski, W.; Steinfeld, A.

    2008-01-01

    A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates

  3. ε-Polylysine-based thermo-responsive adsorbents for immunoglobulin adsorption-desorption under mild conditions.

    Science.gov (United States)

    Maruyama, Masashi; Shibuya, Keisuke

    2017-08-22

    Thermo-responsive adsorbents for immunoglobulin G (IgG) employing ε-polylysine (EPL) as a polymer backbone were developed. The introduction of mercaptoethylpyridine (MEP) as an IgG-binding ligand and hydrophobization of side chains afforded thermo-responsive IgG adsorbents, whose thermo-responsive IgG desorption ratio was up to 88% (EPL/MEP derivative 3m). The changes in surface densities of active MEP groups, which are caused by thermal conformational changes of the adsorbents, play key roles for IgG desorption. Although a trade-off of IgG adsorption capacity and IgG desorption ratio was observed, the present study offers a novel molecular design for thermo-responsive adsorbents with high synthetic accessibility and potentially low toxicity.

  4. High aspect ratio silicon nanomoulds for UV embossing fabricated by directional thermal oxidation using an oxidation mask

    International Nuclear Information System (INIS)

    Chen, L Q; Chan-Park, Mary B; Yan, Y H; Zhang Qing; Li, C M; Zhang Jun

    2007-01-01

    Nanomoulding is simple and economical but moulds with nanoscale features are usually prohibitively expensive to fabricate because nanolithographic techniques are mostly serial and time-consuming for large-area patterning. This paper describes a novel, simple and inexpensive parallel technique for fabricating nanoscale pattern moulds by silicon etching followed by thermal oxidation. The mask pattern can be made by direct photolithography or photolithography followed by metal overetching for submicron- and nanoscale features, respectively. To successfully make nanoscale channels having a post-oxidation cross-sectional shape similar to that of the original channel, an oxidation mask to promote unidirectional (specifically horizontal) oxide growth is found to be essential. A silicon nitride or metal mask layer prevents vertical oxidation of the Si directly beneath it. Without this mask, rectangular channels become smaller but are V-shaped after oxidation. By controlling the silicon etch depth and oxidation time, moulds with high aspect ratio channels having widths ranging from 500 to 50 nm and smaller can be obtained. The nanomould, when passivated with a Teflon-like layer, can be used for first-generation replication using ultraviolet (UV) nanoembossing and second-generation replication in other materials, such as polydimethylsiloxane (PDMS). The PDMS stamp, which was subsequently coated with Au, was used for transfer printing of Au electrodes with a 600 nm gap which will find applications in plastics nanoelectronics

  5. Thermal and Mechanical Non-Equilibrium Effects on Turbulent Flows: Fundamental Studies of Energy Exchanges Through Direct Numerical Simulations, Molecular Simulations and Experiments

    Science.gov (United States)

    2016-02-26

    photochemical TNE generation, and chemistry of non- equilibrium phenomena. We have investigated a new concept to generate turbulence using photo-initiated...AFRL-AFOSR-VA-TR-2016-0104 Thermal and mechanical non- equilibrium effects on turbulent flows:fundamental studies of energy exchanges through direct...Performance 3. DATES COVERED (From - To) 15-09-2012 to 14-11-2015 4. TITLE AND SUBTITLE Thermal and mechanical non- equilibrium effects on turbulent

  6. Thermal stability of hydrogenated small-diameter carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Podlivaev, A. I., E-mail: AIPodlivayev@mephi.ru; Openov, L. A. [National Research Nuclear University “MEPhI” (Russian Federation)

    2017-02-15

    The initial stage of hydrogen desorption from fully hydrogenated carbon nanotubes (3.0) and (2.2) is numerically studied by the molecular dynamics method. The temperature dependence of the desorption rate is directly determined at T = 1800–2500 K. The characteristic desorption times are determined at temperatures outside this range by extrapolation. It is shown that hydrogen desorption leads to the appearance of electronic states in the band gap.

  7. Operating conditions of an open and direct solar thermal Brayton cycle with optimised cavity receiver and recuperator

    International Nuclear Information System (INIS)

    Le Roux, W.G.; Bello-Ochende, T.; Meyer, J.P.

    2011-01-01

    The small-scale open and direct solar thermal Brayton cycle with recuperator has several advantages, including low cost, low operation and maintenance costs and it is highly recommended. The main disadvantages of this cycle are the pressure losses in the recuperator and receiver, turbomachine efficiencies and recuperator effectiveness, which limit the net power output of such a system. The irreversibilities of the solar thermal Brayton cycle are mainly due to heat transfer across a finite temperature difference and fluid friction. In this paper, thermodynamic optimisation is applied to concentrate on these disadvantages in order to optimise the receiver and recuperator and to maximise the net power output of the system at various steady-state conditions, limited to various constraints. The effects of wind, receiver inclination, rim angle, atmospheric temperature and pressure, recuperator height, solar irradiance and concentration ratio on the optimum geometries and performance were investigated. The dynamic trajectory optimisation method was applied. Operating points of a standard micro-turbine operating at its highest compressor efficiency and a parabolic dish concentrator diameter of 16 m were considered. The optimum geometries, minimum irreversibility rates and maximum receiver surface temperatures of the optimised systems are shown. For an environment with specific conditions and constraints, there exists an optimum receiver and recuperator geometry so that the system produces maximum net power output. -- Highlights: → Optimum geometries exist such that the system produces maximum net power output. → Optimum operating conditions are shown. → Minimum irreversibility rates and minimum entropy generation rates are shown. → Net power output was described in terms of total entropy generation rate. → Effects such as wind, recuperator height and irradiance were investigated.

  8. Direct thermal to electrical energy conversion using 9.5/65/35 PLZT ceramics in the ergodic relaxor phase.

    Science.gov (United States)

    Chin, Thomas K; Lee, Felix Y; McKinley, Ian M; Goljahi, Sam; Lynch, Christopher S; Pilon, Laurent

    2012-11-01

    This paper reports on direct thermal to electrical energy conversion by performing the Olsen cycle on 9.5/65/35 lead lanthanum zirconate titanate (PLZT). The Olsen cycle consists of two isothermal and two isoelectric field processes in the electric displacement versus electric field diagram. It was performed by alternatively dipping the material in hot and cold dielectric fluid baths under specified electric fields. The effects of applied electric field, sample thickness, electrode material, operating temperature, and cycle frequency on the energy and power densities were investigated. A maximum energy density of 637 ± 20 J/L/cycle was achieved at 0.054 Hz with a 250-μm-thick sample featuring Pt electrodes and coated with a silicone conformal coating. The operating temperatures varied between 3°C and 140°C and the electric field was cycled between 0.2 and 6.0 MV/m. A maximum power density of 55 ± 8 W/L was obtained at 0.125 Hz under the same operating temperatures and electric fields. The dielectric strength of the material, and therefore the energy and power densities generated, increased when the sample thickness decreased from 500 to 250 μm. Furthermore, the electrode material was found to have no significant effect on the energy and power densities for samples subject to the same operating temperatures and electric fields. However, samples with electrode material possessing thermal expansion coefficients similar to that of PLZT were capable of withstanding larger temperature swings. Finally, a fatigue test showed that the power generation gradually degraded when the sample was subject to repeated thermoelectrical loading.

  9. Ionic Adsorption and Desorption of CNT Nanoropes

    Directory of Open Access Journals (Sweden)

    Jun-Jun Shang

    2016-09-01

    Full Text Available A nanorope is comprised of several carbon nanotubes (CNTs with different chiralities. A molecular dynamic model is built to investigate the ionic adsorption and desorption of the CNT nanoropes. The charge distribution on the nanorope is obtained by using a modified gradient method based on classical electrostatic theory. The electrostatic interactions among charged carbon atoms are calculated by using the Coulomb law. It was found here that the charged nanorope can adsorb heavy metal ions, and the adsorption and desorption can be realized by controlling the strength of applied electric field. The distance between the ions and the nanorope as well as the amount of ions have an effect on the adsorption capacity of the nanorope. The desorption process takes less time than that of adsorption. The study indicates that the CNT nanorope can be used as a core element of devices for sewage treatment.

  10. Thermal soil remediation

    International Nuclear Information System (INIS)

    Nelson, D.

    1999-01-01

    The environmental properties and business aspects of thermal soil remediation are described. Thermal soil remediation is considered as being the best option in cleaning contaminated soil for reuse. The thermal desorption process can remove hydrocarbons such as gasoline, kerosene and crude oil, from contaminated soil. Nelson Environmental Remediation (NER) Ltd. uses a mobile thermal desorption unit (TDU) with high temperature capabilities. NER has successfully applied the technology to target heavy end hydrocarbon removal from Alberta's gumbo clay in all seasons. The TDU consist of a feed system, a counter flow rotary drum kiln, a baghouse particulate removal system, and a secondary combustion chamber known as an afterburner. The technology has proven to be cost effective and more efficient than bioremediation and landfarming

  11. STM-Induced Hydrogen Desorption via a Hole Resonance

    DEFF Research Database (Denmark)

    Stokbro, Kurt; Thirstrup, C.; Sakurai, M.

    1998-01-01

    We report STM-induced desorption of H from Si(100)-H(2 X 1) at negative sample bias. The desorption rate exhibits a power-law dependence on current and a maximum desorption rate at -7 V. The desorption is explained by vibrational heating of H due to inelastic scattering of tunneling holes...... with the Si-H 5 sigma hole resonance. The dependence of desorption rate on current and bias is analyzed using a novel approach for calculating inelastic scattering, which includes the effect of the electric field between tip and sample. We show that the maximum desorption rate at -7 V is due to a maximum...

  12. 5th International Workshop on Desorption Induced by Electronic Transitions

    CERN Document Server

    Jennison, Dwight R; Stechel, Ellen B; DIET V; Desorption induced by electronic transitions

    1993-01-01

    This volume in the Springer Series on Surface Sciences presents a recent account of advances in the ever-broadening field of electron-and photon-stimulated sur­ face processes. As in previous volumes, these advances are presented as the proceedings of the International Workshop on Desorption Induced by Electronic Transitions; the fifth workshop (DIET V) was held in Taos, New Mexico, April 1-4, 1992. It will be abundantly clear to the reader that "DIET" is not restricted to desorption, but has for several years included photochemistry, non-thermal surface modification, exciton self-trapping, and many other phenomena that are induced by electron or photon bombardment. However, most stimulated surface processes do share a common physics: initial electronic excitation, localization of the excitation, and conversion of electronic energy into nuclear kinetic energy. It is the rich variation of this theme which makes the field so interesting and fruitful. We have divided the book into eleven parts in orde...

  13. Modeling photo-desorption in high current storage rings

    International Nuclear Information System (INIS)

    Barletta, W.A.

    1991-01-01

    High luminosity flavor factories are characterized by high fluxes of synchrotron radiation that lead to thermal management difficulties. The associated photo-desorption from the vacuum chamber walls presents an additional design challenge, providing a vacuum system suitable for maintaining acceptable beam-gas lifetimes and low background levels of scattered radiation in the detector. Achieving acceptable operating pressures (1-10 nTorr) with practical pumping schemes requires the use of materials with low photodesorption efficiency operating in a radiation environment beyond that of existing storage rings. Extrapolating the existing photo-desorption data base to the design requirements of high luminosity colliders requires a physical model of the differential cleaning in the vacuum chamber. The authors present a simple phenomenological model of photodesorption that includes effects of dose dependence and diffuse photon reflection to compute the leveling of gas loads in beamlines of high current storage rings that typify heavy flavor factories. This model is also used to estimate chamber commissioning times

  14. Methanol ice co-desorption as a mechanism to explain cold methanol in the gas-phase

    Science.gov (United States)

    Ligterink, N. F. W.; Walsh, C.; Bhuin, R. G.; Vissapragada, S.; van Scheltinga, J. Terwisscha; Linnartz, H.

    2018-05-01

    Context. Methanol is formed via surface reactions on icy dust grains. Methanol is also detected in the gas-phase at temperatures below its thermal desorption temperature and at levels higher than can be explained by pure gas-phase chemistry. The process that controls the transition from solid state to gas-phase methanol in cold environments is not understood. Aims: The goal of this work is to investigate whether thermal CO desorption provides an indirect pathway for methanol to co-desorb at low temperatures. Methods: Mixed CH3OH:CO/CH4 ices were heated under ultra-high vacuum conditions and ice contents are traced using RAIRS (reflection absorption IR spectroscopy), while desorbing species were detected mass spectrometrically. An updated gas-grain chemical network was used to test the impact of the results of these experiments. The physical model used is applicable for TW Hya, a protoplanetary disk in which cold gas-phase methanol has recently been detected. Results: Methanol release together with thermal CO desorption is found to be an ineffective process in the experiments, resulting in an upper limit of ≤ 7.3 × 10-7 CH3OH molecules per CO molecule over all ice mixtures considered. Chemical modelling based on the upper limits shows that co-desorption rates as low as 10-6 CH3OH molecules per CO molecule are high enough to release substantial amounts of methanol to the gas-phase at and around the location of the CO thermal desorption front in a protoplanetary disk. The impact of thermal co-desorption of CH3OH with CO as a grain-gas bridge mechanism is compared with that of UV induced photodesorption and chemisorption.

  15. Development of a thermal desorption modulator for gas chromatography

    NARCIS (Netherlands)

    Geus, H.J.; Boer, de J.; Brinkman, U.A.Th.

    1997-01-01

    The separation space in gas chromatography can be enhanced dramatically by the comprehensive coupling of two independent separation dimensions. An interface between the two columns must accumulate analytes eluting from the first dimension, focus them and at the appropriate moment transfer them to

  16. Direct spectroscopic evidence for competition between thermal molecular agitation and magnetic field in a tetrameric protein in aqueous solution

    Science.gov (United States)

    Calabrò, Emanuele; Magazù, Salvatore

    2018-05-01

    Samples of a typical tetrameric protein, the hemoglobin, at the concentration of 150 mg/ml in bidistilled water solution, were exposed to a uniform magnetic field at 200 mT at different temperatures of 15∘C, 40∘C and 65∘C. Fourier Transform Infrared Spectroscopy was used to analyze the response of the secondary structure of the protein to both stress agents, heating and static magnetic field. The most relevant result which was observed was the significant increasing in intensity of the Amide I band after exposure to the uniform magnetic field at the room temperature of 15∘C. This result can be explained assuming that protein's α-helices aligned along the direction of the applied magnetic field due to their large dipole moment, inducing the alignment of the entire protein. Increasing of temperature up to 40∘C and 65∘C induced a significant reduction of the increasing in intensity of the Amide I band. This effect may be easily explained assuming that Brownian motion of the protein in water solution caused by thermal molecular agitation increased with increasing of temperature, contrasting the effect of the torque of the magnetic field applied to the protein in water solution.

  17. Thermal cure effects on electromechanical properties of conductive wires by direct ink write for 4D printing and soft machines

    Science.gov (United States)

    Mu, Quanyi; Dunn, Conner K.; Wang, Lei; Dunn, Martin L.; Qi, H. Jerry; Wang, Tiejun

    2017-04-01

    Recent developments in soft materials and 3D printing are promoting the rapid development of novel technologies and concepts, such as 4D printing and soft machines, that in turn require new methods for fabricating conductive materials. Despite the ubiquity of silver nanoparticles (NPs) in the conducting electrodes of printed electronic devices, their potential use in stretchable conductors has not been fully explored in 4D printing and soft machines. This paper studies the effect of thermal cure conditions on conductivity and electro-mechanical behaviors of silver ink by the direct ink write (DIW) printing approach. We found that the electro-mechanical properties of silver wires can be tailored by controlling cure time and cure temperature to achieve conductivity as well as stretchability. For the silver NP ink we used in the experiments, silver wires cured at 80 °C for 10-30 min have conductivity >1% bulk silver, Young’s modulus printed silver ink patterns on the surface of 3D printed polymer parts, with the future goal of constructing fully 3D printed arbitrarily formed soft and stretchable devices and of applying them to 4D printing. We demonstrated a fully printed functional soft-matter sensor and a circuit element that can be stretched by as much as 45%.

  18. Secondary ion shadow-cone enhanced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Chechen Chang (Hawaii Univ., Honolulu (USA). Dept. of Chemistry)

    1990-02-01

    The incident angle dependence of the secondary particle emission process under keV ion bombardment has been investigated. The results from the full molecular dynamics calculations indicate that the flux anisotropy of the incident beam, resulting from the non-uniform impact parameters for the surface atom of a single crystal, affects the particle desorption in a systematic fashion. The enhanced desorption at certain angles of incidence corresponds to the intensive focusing of the incident beam to the near-surface atom and the extended dissipation of momentum by large-angle scattering. This observation has let us to develop a new theoretical model in which the enhanced desorption is described by the distance of closest encounter along the trajectory of the incident particle to the surface atom. The computer time for the simulation of the incident-angle-dependent emission process is significantly reduced. The results from the calculation based on this model are in good agreement both with the results from the full dynamics calculation and with the experimental results. The new model also allows a complementary evaluation of the microscopic dynamics involved in the shadow-cone enhanced desorption. (author).

  19. Exciton-Promoted Desorption From Solid Water Surfaces A2

    DEFF Research Database (Denmark)

    McCoustra, M.R.S.; Thrower, J.D.

    2018-01-01

    Abstract Desorption from solid water surfaces resulting from interaction with electromagnetic and particle radiation is reviewed in the context of the role of nonthermal desorption in astrophysical environments. Experimental observations are interpreted in terms of mechanisms sharing a common basis...

  20. Data compilation for particle-impact desorption, 2

    International Nuclear Information System (INIS)

    Oshiyama, Takashi; Nagai, Siro; Ozawa, Kunio; Takeutchi, Fujio.

    1985-07-01

    The particle impact desorption is one of the elementary processes of hydrogen recycling in controlled thermonuclear fusion reactors. We have surveyed the literature concerning the ion impact desorption and photon stimulated desorption published through the end of 1984 and compiled the data on the desorption cross sections and yields with the aid of a computer. This report presents the results of the compilation in graphs and tables as functions of incident energy, surface temperature and surface coverage. (author)

  1. Desorption of intrinsic cesium from smectite: inhibitive effects of clay particle organization on cesium desorption.

    Science.gov (United States)

    Fukushi, Keisuke; Sakai, Haruka; Itono, Taeko; Tamura, Akihiro; Arai, Shoji

    2014-09-16

    Fine clay particles have functioned as transport media for radiocesium in terrestrial environments after nuclear accidents. Because radiocesium is expected to be retained in clay minerals by a cation-exchange reaction, ascertaining trace cesium desorption behavior in response to changing solution conditions is crucially important. This study systematically investigated the desorption behavior of intrinsic Cs (13 nmol/g) in well-characterized Na-montmorillonite in electrolyte solutions (NaCl, KCl, CaCl2, and MgCl2) under widely differing cation concentrations (0.2 mM to 0.2 M). Batch desorption experiments demonstrated that Cs(+) desorption was inhibited significantly in the presence of the environmental relevant concentrations of Ca(2+) and Mg(2+) (>0.5 mM) and high concentrations of K(+). The order of ability for Cs desorption was Na(+) = K(+) > Ca(2+) = Mg(2+) at the highest cation concentration (0.2 M), which is opposite to the theoretical prediction based on the cation-exchange selectivity. Laser diffraction grain-size analyses revealed that the inhibition of Cs(+) desorption coincided with the increase of the clay tactoid size. Results suggest that radiocesium in the dispersed fine clay particles adheres on the solid phase when the organization of swelling clay particles occurs because of changes in solution conditions caused by both natural processes and artificial treatments.

  2. Effects of chemical oxidation on sorption and desorption of PAHs in typical Chinese soils

    International Nuclear Information System (INIS)

    Chen Wei; Hou Lei; Luo Xiaoli; Zhu Lingyan

    2009-01-01

    In situ chemical oxidation is a commonly applied soil and groundwater remediation technology, but can have significant effects on soil properties, which in turn might affect fate and transport of organic contaminants. In this study, it was found that oxidation treatment resulted mainly in breakdown of soil organic matter (SOM) components. Sorption of naphthalene and phenanthrene to the original soils and the KMnO 4 -treated soils was linear, indicating that hydrophobic partitioning to SOM was the predominant mechanism for sorption. Desorption from the original and treated soils was highly resistant, and was well modeled with a biphasic desorption model. Desorption of residual naphthalene after treating naphthalene-contaminated soils with different doses of KMnO 4 also followed the biphasic desorption model very well. It appears that neither changes of soil properties caused by chemical oxidation nor direct chemical oxidation of contaminated soils had a noticeable effect on the nature of PAH-SOM interactions. - Chemical oxidation of soils had little effect on the mechanisms controlling sorption and desorption of PAHs.

  3. Interconnection of thermal parameters, microstructure and mechanical properties in directionally solidified Sn–Sb lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Marcelino; Costa, Thiago [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Rocha, Otávio [Federal Institute of Education, Science and Technology of Pará — IFPA, 66093-020 Belém, PA (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos — UFSCar, 13565-905 São Carlos, SP (Brazil); Cheung, Noé, E-mail: cheung@fem.unicamp.br [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil)

    2015-08-15

    Considerable effort is being made to develop lead-free solders for assembling in environmental-conscious electronics, due to the inherent toxicity of Pb. The search for substitute alloys of Pb–Sn solders has increased in order to comply with different soldering purposes. The solder must not only meet the expected levels of electrical performance but may also have appropriate mechanical strength, with the absence of cracks in the solder joints. The Sn–Sb alloy system has a range of compositions that can be potentially included in the class of high temperature solders. This study aims to establish interrelations of solidification thermal parameters, microstructure and mechanical properties of Sn–Sb alloys (2 wt.%Sb and 5.5 wt.%Sb) samples, which were directionally solidified under cooling rates similar to those of reflow procedures in industrial practice. A complete high-cooling rate cellular growth is shown to be associated with the Sn–2.0 wt.%Sb alloy and a reverse dendrite-to-cell transition is observed for the Sn–5.5 wt.%Sb alloy. Strength and ductility of the Sn–2.0 wt.%Sb alloy are shown not to be affected by the cellular spacing. On the other hand, a considerable variation in these properties is associated with the cellular region of the Sn–5.5 wt.%Sb alloy casting. - Graphical abstract: Display Omitted - Highlights: • The microstructure of the Sn–2 wt.%Sb alloy is characterized by high-cooling rates cells. • Reverse dendrite > cell transition occurs for Sn–5.5 wt.%Sb alloy: cells prevail for cooling rates > 1.2 K/s. • Sn–5.5 wt.%Sb alloy: the dendritic region occurs for cooling rates < 0.9 K/s. • Sn–5.5 wt.%Sb alloy: tensile properties are improved with decreasing cellular spacing.

  4. EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

    KAUST Repository

    Piskorz, Danielle

    2016-11-23

    We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant\\'s atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth\\'s atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L-band observations and three epochs of Keck NIRSPEC K-band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross-correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40 +/- 15 km s(-1), a true mass of 1.02(-0.28)(+0.61) M-J, a nearly face-on orbital inclination of 15(-5)(+60), and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with 11 years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.

  5. Turbulence Generation Using Localized Sources of Energy: Direct Numerical Simulations and the Effects of Thermal Non-Equilibrium

    Science.gov (United States)

    Maqui, Agustin Francisco

    Turbulence in high-speed flows is an important problem in aerospace applications, yet extremely difficult from a theoretical, computational and experimental perspective. A main reason for the lack of complete understanding is the difficulty of generating turbulence in the lab at a range of speeds which can also include hypersonic effects such as thermal non-equilibrium. This work studies the feasibility of a new approach to generate turbulence based on laser-induced photo-excitation/dissociation of seeded molecules. A large database of incompressible and compressible direct numerical simulations (DNS) has been generated to systematically study the development and evolution of the flow towards realistic turbulence. Governing parameters and the conditions necessary for the establishment of turbulence, as well as the length and time scales associated with such process, are identified. For both the compressible and incompressible experiments a minimum Reynolds number is found to be needed for the flow to evolve towards fully developed turbulence. Additionally, for incompressible cases a minimum time scale is required, while for compressible cases a minimum distance from the grid and limit on the maximum temperature introduced are required. Through an extensive analysis of single and two point statistics, as well as spectral dynamics, the primary mechanisms leading to turbulence are shown. As commonly done in compressible turbulence, dilatational and solenoidal components are separated to understand the effect of acoustics on the development of turbulence. Finally, a large database of forced isotropic turbulence has been generated to study the effect of internal degrees of freedom on the evolution of turbulence.

  6. Improved fatty acid detection in micro-algae and aquatic meiofauna species using a direct thermal desorption interface combined with comprehensive gas chromatography-time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Akoto, L.; Stellaard, F.; Irth, H.; Vreuls, R.J.J.; Pel, R.

    2008-01-01

    Comprehensive two-dimensional gas chromatography (GC × GC) with time-of-flight mass spectrometry detection is used to profile the fatty acid composition of whole/intact aquatic microorganisms such as the common fresh water green algae Scenedesmus acutus and the filamentous cyanobacterium Limnothrix

  7. Improved fatty acid detection in micro-algae and aquatic meiofauna species using a direct thermal desorption interface combined with comprehensive gas chromatography–time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Akoto, L.; Stellaard, F.; Irth, H.; Vreuls, R.J.J.; Pel, R.

    2008-01-01

    Comprehensive two-dimensional gas chromatography (GC × GC) with time-of-flight mass spectrometry detection is used to profile the fatty acid composition of whole/intact aquatic microorganisms such as the common fresh water green algae Scenedesmus acutus and the filamentous cyanobacterium Limnothrix

  8. Improved fatty acid detection in micro-algae and aquatic meiofauna species using a direct thermal desorption interface combined with comprehensive gas chromatography-time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Akoto, Lawrence; Stellaard, Frans; Irth, Hubertus; Vreuls, Rene J. J.; Pel, Roel

    2008-01-01

    Comprehensive two-dimensional gas chromatography (GC x GC) with time-of-flight mass spectrometry detection is used to profile the fatty acid composition of whole/intact aquatic microorganisms such as the common fresh water green algae Scenedesmus acutus and the filamentous cyanobacterium Limnothrix

  9. Hydrocarbon analysis using desorption atmospheric pressure chemical ionization

    KAUST Repository

    Jjunju, Fred Paul Mark; Badu-Tawiah, Abraham K.; Li, Anyin; Soparawalla, Santosh; Roqan, Iman S.; Cooks, Robert Graham

    2013-01-01

    Characterization of the various petroleum constituents (hydronaphthalenes, thiophenes, alkyl substituted benzenes, pyridines, fluorenes, and polycyclic aromatic hydrocarbons) was achieved under ambient conditions without sample preparation by desorption atmospheric pressure chemical ionization (DAPCI). Conditions were chosen for the DAPCI experiments to control whether ionization was by proton or electron transfer. The protonated molecule [M+H]+ and the hydride abstracted [MH]+ form were observed when using an inert gas, typically nitrogen, to direct a lightly ionized plasma generated by corona discharge onto the sample surface in air. The abundant water cluster ions generated in this experiment react with condensed-phase functionalized hydrocarbon model compounds and their mixtures at or near the sample surface. On the other hand, when naphthalene was doped into the DAPCI gas stream, its radical cation served as a charge exchange reagent, yielding molecular radical cations (M+) of the hydrocarbons. This mode of sample ionization provided mass spectra with better signal/noise ratios and without unwanted side-products. It also extended the applicability of DAPCI to petroleum constituents which could not be analyzed through proton transfer (e.g., higher molecular PAHs such as chrysene). The thermochemistry governing the individual ionization processes is discussed and a desorption/ionization mechanism is inferred. © 2012 Elsevier B.V.

  10. Electron-stimulated desorption from condensed branched alkanes

    International Nuclear Information System (INIS)

    Kelber, J.A.; Knotek, M.L.

    1982-01-01

    Desorption of H + , CH 3+ , H 2+ , and D + have been measured as a function of electron excitation energy for solid neopentane, tetramethylsilane and two deuterated isomers of isobutane. The evidence shows that C-C (or Si-C) and C-H bonds are broken by electronic excitations localized on methyl groups, in contrast to CH 3+ production in gas-phase neopentane, and that these excitations are the final states of decay processes initiated by creation of a hole in the C2s level, or, in tetramethylsilane, the C2s/Si3s level. This is in accord with other evidence which shows that localized multi-valence hole states result in C-H, C-C, Si-C and Si-H dissociation, and that such states may be excited either directly or by shakeup, by decay from a C2s hole, or by decay for a C1s core hole. It is apparent then, that dissociation and desorption of ions from covalent materials is a multi (electron) hole mechanism, and that the means of localizing the excitation energy in such systems involves multi-hole correlation

  11. Hydrocarbon analysis using desorption atmospheric pressure chemical ionization

    KAUST Repository

    Jjunju, Fred Paul Mark

    2013-07-01

    Characterization of the various petroleum constituents (hydronaphthalenes, thiophenes, alkyl substituted benzenes, pyridines, fluorenes, and polycyclic aromatic hydrocarbons) was achieved under ambient conditions without sample preparation by desorption atmospheric pressure chemical ionization (DAPCI). Conditions were chosen for the DAPCI experiments to control whether ionization was by proton or electron transfer. The protonated molecule [M+H]+ and the hydride abstracted [MH]+ form were observed when using an inert gas, typically nitrogen, to direct a lightly ionized plasma generated by corona discharge onto the sample surface in air. The abundant water cluster ions generated in this experiment react with condensed-phase functionalized hydrocarbon model compounds and their mixtures at or near the sample surface. On the other hand, when naphthalene was doped into the DAPCI gas stream, its radical cation served as a charge exchange reagent, yielding molecular radical cations (M+) of the hydrocarbons. This mode of sample ionization provided mass spectra with better signal/noise ratios and without unwanted side-products. It also extended the applicability of DAPCI to petroleum constituents which could not be analyzed through proton transfer (e.g., higher molecular PAHs such as chrysene). The thermochemistry governing the individual ionization processes is discussed and a desorption/ionization mechanism is inferred. © 2012 Elsevier B.V.

  12. Desorption, partitioning, and dechlorination characteristics of PCBs in sediments in interaction with reactive activated carbon.

    Science.gov (United States)

    Choi, Hyeok; Lawal, Wasiu; Al-Abed, Souhail R

    2015-04-28

    Sediment (WHS) in Waukegan Harbor, Illinois, heavily contaminated and aged with polychlorinated biphenyls (PCBs), was treated with reactive activated carbon (RAC) impregnated with palladized iron nanoparticles. Lab test proceeded in a direct mixing configuration of RAC and WHS. A compartment configuration, where RAC was physically separated from WHS, was also designed to trace the sequential transport and fate of PCBs, including desorption, adsorption, dechlorination, and re-partitioning. PCBs, once desorbed from WHS, were immediately sequestrated to RAC and subject to dechlorination. Direct mixing of WHS with RAC was one-order of magnitude more effective for dechlorination than compartment configuration. Compared to their desorption-followed by-adsorption route, direct physical contact of RAC with PCBs bound to WHS exhibited negligible contribution to the availability of PCBs for dechlorination reaction. Addition of RAC even in compartment configuration facilitated PCBs desorption from WHS. However, slow desorption of PCBs limited overall performance, resulting in a five-order of magnitude lower dechlorination yield when compared with treatment of purely aqueous PCBs. The low dechlorination yield reflected real world complexities in treating 3.19% organic carbon-containing WHS aged with PCBs for 40 years. These observations were further supported when compared with results on clean Cesar Creek sediment spiked with 2-chlorinated biphenyls. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Thermal treatment of natural goethite: Thermal transformation and physical properties

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Haibo [Laboratory for Nanomineralogy and Environmental Material, School of Resources and Environmental Engineering, Hefei University of Technology (China); School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (Australia); Chen, Tianhu, E-mail: chentianhu@hfut.edu.cn [Laboratory for Nanomineralogy and Environmental Material, School of Resources and Environmental Engineering, Hefei University of Technology (China); Zou, Xuehua; Qing, Chengsong [Laboratory for Nanomineralogy and Environmental Material, School of Resources and Environmental Engineering, Hefei University of Technology (China); Frost, Ray L., E-mail: r.frost@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (Australia)

    2013-09-20

    Highlights: • We have characterized the thermal transformation of natural goethite. • The heated products showed a topotactical relationship to the original mineral. • The N2 adsorption isotherm provided the variation of surface area and pore size distribution with temperature. • The significant increase in surface area was attributed to the formation of regularly arranged slit-shaped micropores. • The hematite derived from heating goethite has application as an adsorbent and catalyst. - Abstract: XRD (X-ray diffraction), XRF (X-ray fluorescence), TG (thermogravimetry), FT-IES (Fourier transform infrared emission spectroscopy), FESEM (field emission scanning electron microscope), TEM (transmission electron microscope) and nitrogen–adsorption–desorption analysis were used to characterize the composition and thermal evolution of the structure of natural goethite. The in situ FT-IES demonstrated the start temperature (250 °C) of the transformation of natural goethite to hematite and the thermodynamic stability of protohematite between 250 and 600 °C. The heated products showed a topotactic relationship to the original mineral based on SEM analysis. Finally, the nitrogen–adsorption–desorption isotherm provided the variation of surface area and pore size distribution as a function of temperature. The surface area displayed a remarkable increase up to 350 °C, and then decreased above this temperature. The significant increase in surface area was attributed to the formation of regularly arranged slit-shaped micropores running parallel to elongated direction of hematite microcrystal. The main pore size varied from 0.99 nm to 3.5 nm when heating temperature increases from 300 to 400 °C. The hematite derived from heating goethite possesses high surface area and favors the possible application of hematite as an adsorbent as well as catalyst carrier.

  14. Thermal treatment of natural goethite: Thermal transformation and physical properties

    International Nuclear Information System (INIS)

    Liu, Haibo; Chen, Tianhu; Zou, Xuehua; Qing, Chengsong; Frost, Ray L.

    2013-01-01

    Highlights: • We have characterized the thermal transformation of natural goethite. • The heated products showed a topotactical relationship to the original mineral. • The N2 adsorption isotherm provided the variation of surface area and pore size distribution with temperature. • The significant increase in surface area was attributed to the formation of regularly arranged slit-shaped micropores. • The hematite derived from heating goethite has application as an adsorbent and catalyst. - Abstract: XRD (X-ray diffraction), XRF (X-ray fluorescence), TG (thermogravimetry), FT-IES (Fourier transform infrared emission spectroscopy), FESEM (field emission scanning electron microscope), TEM (transmission electron microscope) and nitrogen–adsorption–desorption analysis were used to characterize the composition and thermal evolution of the structure of natural goethite. The in situ FT-IES demonstrated the start temperature (250 °C) of the transformation of natural goethite to hematite and the thermodynamic stability of protohematite between 250 and 600 °C. The heated products showed a topotactic relationship to the original mineral based on SEM analysis. Finally, the nitrogen–adsorption–desorption isotherm provided the variation of surface area and pore size distribution as a function of temperature. The surface area displayed a remarkable increase up to 350 °C, and then decreased above this temperature. The significant increase in surface area was attributed to the formation of regularly arranged slit-shaped micropores running parallel to elongated direction of hematite microcrystal. The main pore size varied from 0.99 nm to 3.5 nm when heating temperature increases from 300 to 400 °C. The hematite derived from heating goethite possesses high surface area and favors the possible application of hematite as an adsorbent as well as catalyst carrier

  15. Desorption of Water from Distinct Step Types on a Curved Silver Crystal

    Directory of Open Access Journals (Sweden)

    Jakrapan Janlamool

    2014-07-01

    Full Text Available We have investigated the adsorption of H2O onto the A and B type steps on an Ag single crystal by temperature programmed desorption. For this study, we have used a curved crystal exposing a continuous range of surface structures ranging from [5(111 × (100] via (111 to [5(111 × (110]. LEED and STM studies verify that the curvature of our sample results predominantly from monoatomic steps. The sample thus provides a continuous array of step densities for both step types. Desorption probed by spatially-resolved TPD of multilayers of H2O shows no dependence on the exact substrate structure and thus confirms the absence of thermal gradients during temperature ramps. In the submonolayer regime, we observe a small and linear dependence of the desorption temperature on the A and B step density. We argue that such small differences are only observable by means of a single curved crystal, which thus establishes new experimental benchmarks for theoretical calculation of chemically accurate binding energies. We propose an origin of the observed behavior based on a “two state” desorption model.

  16. Lead sorption-desorption from organic residues.

    Science.gov (United States)

    Duarte Zaragoza, Victor M; Carrillo, Rogelio; Gutierrez Castorena, Carmen M

    2011-01-01

    Sorption and desorption are mechanisms involved in the reduction of metal mobility and bioavailability in organic materials. Metal release from substrates is controlled by desorption. The capacity of coffee husk and pulp residues, vermicompost and cow manure to adsorb Pb2+ was evaluated. The mechanisms involved in the sorption process were also studied. Organic materials retained high concentrations of lead (up to 36,000 mg L(-1)); however, the mechanisms of sorption varied according to the characteristics of each material: degree of decomposition, pH, cation exchange capacity and percentage of organic matter. Vermicompost and manure removed 98% of the Pb from solution. Lead precipitated in manure and vermicompost, forming lead oxide (PbO) and lead ferrite (PbFe4O7). Adsorption isotherms did not fit to the typical Freundlich and Langmuir equations. Not only specific and non-specific adsorption was observed, but also precipitation and coprecipitation. Lead desorption from vermicompost and cow manure was less than 2%. For remediation of Pb-polluted sites, the application of vermicompost and manure is recommended in places with alkaline soils because Pb precipitation can be induced, whereas coffee pulp residue is recommended for acidic soils where Pb is adsorbed.

  17. Plasma nitriding process by direct current glow discharge at low temperature increasing the thermal diffusivity of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Prandel, L. V.; Somer, A.; Assmann, A.; Camelotti, F.; Costa, G.; Bonardi, C.; Jurelo, A. R.; Rodrigues, J. B.; Cruz, G. K. [Universidade Estadual de Ponta Grossa, Grupo de Espectroscopia Optica e Fotoacustica de Materiais, Departamento de Fisica, Av. Carlos Cavalcanti, 4748, CEP 84030-900, Ponta Grossa, PR (Brazil)

    2013-02-14

    This work reports for the first time on the use of the open photoacoustic cell technique operating at very low frequencies and at room temperature to experimentally determine the thermal diffusivity parameter of commercial AISI304 stainless steel and AISI304 stainless steel nitrided samples. Complementary measurements of X-ray diffraction and scanning electron microscopy were also performed. The results show that in standard AISI 304 stainless steel samples the thermal diffusivity is (4.0 {+-} 0.3) Multiplication-Sign 10{sup -6} m{sup 2}/s. After the nitriding process, the thermal diffusivity increases to the value (7.1 {+-} 0.5) Multiplication-Sign 10{sup -6} m{sup 2}/s. The results are being associated to the diffusion process of nitrogen into the surface of the sample. Carrying out subsequent thermal treatment at 500 Degree-Sign C, the thermal diffusivity increases up to (12.0 {+-} 2) Multiplication-Sign 10{sup -6} m{sup 2}/s. Now the observed growing in the thermal diffusivity must be related to the change in the phases contained in the nitrided layer.

  18. Use of joint-growth directions and rock textures to infer thermal regimes during solidification of basaltic lava flows

    Science.gov (United States)

    Degraff, James M.; Long, Philip E.; Aydin, Atilla

    1989-09-01

    Thermal contraction joints form in the upper and lower solidifying crusts of basaltic lava flows and grow toward the interior as the crusts thicken. Lava flows are thus divided by vertical joints that, by changes in joint spacing and form, define horizontal intraflow layers known as tiers. Entablatures are tiers with joint spacings less than about 40 cm, whereas colonnades have larger joint spacings. We use structural and petrographic methods to infer heat-transfer processes and to constrain environmental conditions that produce these contrasting tiers. Joint-surface morphology indicates overall joint-growth direction and thus identifies the level in a flow where the upper and lower crusts met. Rock texture provides information on relative cooling rates in the tiers of a flow. Lava flows without entablature have textures that develop by relatively slow cooling, and two joint sets that usually meet near their middles, which indicate mostly conductive cooling. Entablature-bearing flows have two main joint sets that meet well below their middles, and textures that indicate fast cooling of entablatures and slow cooling of colonnades. Entablatures always occur in the upper joint sets and sometimes alternate several times with colonnades. Solidification times of entablature-bearing flows, constrained by lower joint-set thicknesses, are much less than those predicted by a purely conductive cooling model. These results are best explained by a cooling model based on conductive heat transfer near a flow base and water-steam convection in the upper part of an entablature-bearing flow. Calculated solidification rates in the upper parts of such flows exceed that of the upper crust of Kilauea Iki lava lake, where water-steam convection is documented. Use of the solidification rates in an available model of water-steam convection yields permeability values that agree with measured values for fractured crystalline rock. We conclude, therefore, that an entablature forms when part

  19. Desorption, partitioning, and dechlorination characteristics of PCBs in sediments in interaction with reactive activated carbon

    International Nuclear Information System (INIS)

    Choi, Hyeok; Lawal, Wasiu; Al-Abed, Souhail R.

    2015-01-01

    Highlights: • Problematic aged real PCBs-contaminated sediment (WHS) was examined. • Performance of reactive activated carbon (RAC) impregnated with Pd–ZVI was tested. • Fate and transport of PCBs bound to WHS in the presence of RAC was fully traced. • Direct mixing configuration was compared with compartment configuration. • Results reflected real world complexities associated with slow desorption of PCBs. - Abstract: Sediment (WHS) in Waukegan Harbor, Illinois, heavily contaminated and aged with polychlorinated biphenyls (PCBs), was treated with reactive activated carbon (RAC) impregnated with palladized iron nanoparticles. Lab test proceeded in a direct mixing configuration of RAC and WHS. A compartment configuration, where RAC was physically separated from WHS, was also designed to trace the sequential transport and fate of PCBs, including desorption, adsorption, dechlorination, and re-partitioning. PCBs, once desorbed from WHS, were immediately sequestrated to RAC and subject to dechlorination. Direct mixing of WHS with RAC was one-order of magnitude more effective for dechlorination than compartment configuration. Compared to their desorption-followed by-adsorption route, direct physical contact of RAC with PCBs bound to WHS exhibited negligible contribution to the availability of PCBs for dechlorination reaction. Addition of RAC even in compartment configuration facilitated PCBs desorption from WHS. However, slow desorption of PCBs limited overall performance, resulting in a five-order of magnitude lower dechlorination yield when compared with treatment of purely aqueous PCBs. The low dechlorination yield reflected real world complexities in treating 3.19% organic carbon-containing WHS aged with PCBs for 40 years. These observations were further supported when compared with results on clean Cesar Creek sediment spiked with 2-chlorinated biphenyls

  20. Desorption, partitioning, and dechlorination characteristics of PCBs in sediments in interaction with reactive activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyeok, E-mail: hchoi@uta.edu [Department of Civil Engineering, The University of Texas at Arlington, 416 Yates Street, Arlington, TX 76019-0308 (United States); Environmental and Earth Sciences Program, The University of Texas at Arlington, 500 Yates Street, Arlington, TX 76019-0049 (United States); Lawal, Wasiu [Environmental and Earth Sciences Program, The University of Texas at Arlington, 500 Yates Street, Arlington, TX 76019-0049 (United States); Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268 (United States)

    2015-04-28

    Highlights: • Problematic aged real PCBs-contaminated sediment (WHS) was examined. • Performance of reactive activated carbon (RAC) impregnated with Pd–ZVI was tested. • Fate and transport of PCBs bound to WHS in the presence of RAC was fully traced. • Direct mixing configuration was compared with compartment configuration. • Results reflected real world complexities associated with slow desorption of PCBs. - Abstract: Sediment (WHS) in Waukegan Harbor, Illinois, heavily contaminated and aged with polychlorinated biphenyls (PCBs), was treated with reactive activated carbon (RAC) impregnated with palladized iron nanoparticles. Lab test proceeded in a direct mixing configuration of RAC and WHS. A compartment configuration, where RAC was physically separated from WHS, was also designed to trace the sequential transport and fate of PCBs, including desorption, adsorption, dechlorination, and re-partitioning. PCBs, once desorbed from WHS, were immediately sequestrated to RAC and subject to dechlorination. Direct mixing of WHS with RAC was one-order of magnitude more effective for dechlorination than compartment configuration. Compared to their desorption-followed by-adsorption route, direct physical contact of RAC with PCBs bound to WHS exhibited negligible contribution to the availability of PCBs for dechlorination reaction. Addition of RAC even in compartment configuration facilitated PCBs desorption from WHS. However, slow desorption of PCBs limited overall performance, resulting in a five-order of magnitude lower dechlorination yield when compared with treatment of purely aqueous PCBs. The low dechlorination yield reflected real world complexities in treating 3.19% organic carbon-containing WHS aged with PCBs for 40 years. These observations were further supported when compared with results on clean Cesar Creek sediment spiked with 2-chlorinated biphenyls.

  1. Qualitative and quantitative analysis of complex temperature-programmed desorption data by multivariate curve resolution

    Science.gov (United States)

    Rodríguez-Reyes, Juan Carlos F.; Teplyakov, Andrew V.; Brown, Steven D.

    2010-10-01

    The substantial amount of information carried in temperature-programmed desorption (TPD) experiments is often difficult to mine due to the occurrence of competing reaction pathways that produce compounds with similar mass spectrometric features. Multivariate curve resolution (MCR) is introduced as a tool capable of overcoming this problem by mathematically detecting spectral variations and correlations between several m/z traces, which is later translated into the extraction of the cracking pattern and the desorption profile for each desorbate. Different from the elegant (though complex) methods currently available to analyze TPD data, MCR analysis is applicable even when no information regarding the specific surface reaction/desorption process or the nature of the desorbing species is available. However, when available, any information can be used as constraints that guide the outcome, increasing the accuracy of the resolution. This approach is especially valuable when the compounds desorbing are different from what would be expected based on a chemical intuition, when the cracking pattern of the model test compound is difficult or impossible to obtain (because it could be unstable or very rare), and when knowing major components desorbing from the surface could in more traditional methods actually bias the quantification of minor components. The enhanced level of understanding of thermal processes achieved through MCR analysis is demonstrated by analyzing three phenomena: i) the cryogenic desorption of vinyltrimethylsilane from silicon, an introductory system where the known multilayer and monolayer components are resolved; ii) acrolein hydrogenation on a bimetallic Pt-Ni-Pt catalyst, where a rapid identification of hydrogenated products as well as other desorbing species is achieved, and iii) the thermal reaction of Ti[N(CH 3) 2] 4 on Si(100), where the products of surface decomposition are identified and an estimation of the surface composition after the

  2. Trapping hydropyrolysates on silica and their subsequent desorption to facilitate rapid fingerprinting by GC-MS

    Energy Technology Data Exchange (ETDEWEB)

    Meredith, W.; Russell, C.A.; Cooper, M.; Snape, C.E. [Nottingham Univ. (United Kingdom). Fuel and Energy Centre; Love, G.D. [Newcastle upon Tyne Univ. (United Kingdom). School of Civil Engineering and Geosciences; Fabbri, D. [Universita di Bologna, Ravenna (Italy). Lab. di Chimica Ambientale; Vane, C.H. [British Geological Society, Keyworth (United Kingdom)

    2004-01-01

    Analytical hydropyrolysis performed under high hydrogen gas pressure (>10 MPa) has been demonstrated to possess the unique ability to release high yields of biomarker hydrocarbons covalently bound within the non-hydrocarbon macromolecular fraction of crude oils and source rocks. This study describes the development of the experimental procedure for trapping the product oils (hydropyrolysates) on silica to facilitate more convenient recovery than conventional collection and to allow analysis by thermal desorption-GC-MS without any prior work-up. Conventionally, the trap has consisted of a stainless steel coil, cooled with dry ice from which the products are recovered in organic solvents. Replacing this with a system in which the hydropyrolysates are adsorbed on a small mass of silica greatly reduces the turn-around time between tests, and aids the recovery and separation of the products. This method has been developed using an oil shale and an oil asphaltene fraction, with the silica trap producing very similar biomarker profiles to that from the conventional trap. The quantitative recovery of hydrocarbons from a light crude oil desorbed from silica under hydropyrolysis conditions demonstrates no significant loss of the high molecular weight n-alkanes (>n-C{sub 10}) for both trapping methods. The use of liquid nitrogen as the trap coolant results in significantly improved recovery of the lower molecular mass constituents. The silica trapping method allows for the hydropyrolysates to be characterised by thermal desorption-GC-MS, which has been investigated both on- and off-line. The oils undergo relatively little cracking during desorption, with similar n-alkane and biomarker profiles being obtained as with normal work-up and GC-MS analysis. Thus, in terms of fingerprinting geomacromolecules, ''hypy-thermal desorption-GC-MS'' appears to have the potential to be developed as an attractive alternative to traditional py-GC-MS. (author)

  3. Update on the direct n-n scattering experiment at the reactor YAGUAR

    Science.gov (United States)

    Stephenson, S. L.; Crawford, B. E.; Furman, W. I.; Lychagin, E. V.; Muzichka, A. Yu.; Nekhaev, G. V.; Sharapov, E. I.; Shvetsov, V. N.; Strelkov, A. V.; Levakov, B. G.; Lyzhin, A. E.; Chernukhin, Yu. I.; Howell, C. R.; Mitchell, G. E.; Tornow, W.; Showalter-Bucher, R. A.

    2013-10-01

    The first direct measurement of the 1S0 neutron-neutron scattering experiment using the YAGUAR aperiodic reactor at the Russian Federal Nuclear Center - All Russian Research Institute of Technical Physics has preliminary results. Thermal neutrons are scattered from a thermal neutron ``gas'' within the scattering chamber of the reactor and measured via time-of-flight. These initial results show an unexpectedly large thermal neutron background now understood to be from radiation-induced desorption within the scattering chamber. Analysis of the neutron time-of-flight spectra suggests neutron scattering from H2 and possibly H2O molecules. An experimental value for the desorption yield ηγ of 0.02 molecules/gamma agrees with modeled results. Techniques to reduce the effect of the nonthermal desorption will be presented. This work was supported in part by ISTC project No. 2286, Russia Found. Grant 01-02-17181, the US DOE grants Nos. DE-FG02-97-ER41042 and DE-FG02-97-ER41033, and by the US NSF through Award Nos. 0107263 and 0555652.

  4. Assessment of MARS for downcomer multi-dimensional thermal hydraulics during LBLOCA reflood using KAERI air-water direct vessel injection tests

    Energy Technology Data Exchange (ETDEWEB)

    Won-Jae, Lee; Kwi-Seok, Ha; Chul-Hwa, Song [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

    2001-07-01

    The MARS code has been assessed for the downcomer multi-dimensional thermal hydraulics during a large break loss-of-coolant accident (LBLOCA) reflood of Korean Next Generation Reactor (KNGR) that adopted an upper direct vessel injection (DVI) design. Direct DVI bypass and downcomer level sweep-out tests carried out at 1/50-scale air-water DVI test facility are simulated to examine the capability of MARS. Test conditions are selected such that they represent typical reflood conditions of KNGR, that is, DVI injection velocities of 1.0 {approx} 1.6 m/sec and air injection velocities of 18.0 {approx} 35.0 m/sec, for single and double DVI configurations. MARS calculation is first adjusted to the experimental DVI film distribution that largely affects air-water interaction in a scaled-down downcomer, then, the code is assessed for the selected test matrix. With some improvements of MARS thermal-hydraulic (T/H) models, it has been demonstrated that the MARS code is capable of simulating the direct DVI bypass and downcomer level sweep-out as well as the multi-dimensional thermal hydraulics in downcomer, where condensation effect is excluded. (authors)

  5. Thermal enhancement of charge and discharge cycles for adsorbed natural gas storage

    KAUST Repository

    Rahman, Kazi Afzalur; Loh, Wai Soong; Chakraborty, Anutosh; Saha, Bidyut Baran; Chun, Won Gee; Ng, Kim Choon

    2011-01-01

    The usage of adsorbed natural gas (ANG) storage is hindered by the thermal management during the adsorption and desorption processes. An effective thermal enhancement is thus essential for the development of the ANG technology and the motivation

  6. Performance of two resin-containing blood culture media in detection of bloodstream infections and in direct matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) broth assays for isolate identification: clinical comparison of the BacT/Alert Plus and Bactec Plus systems.

    Science.gov (United States)

    Fiori, Barbara; D'Inzeo, Tiziana; Di Florio, Viviana; De Maio, Flavio; De Angelis, Giulia; Giaquinto, Alessia; Campana, Lara; Tanzarella, Eloisa; Tumbarello, Mario; Antonelli, Massimo; Sanguinetti, Maurizio; Spanu, Teresa

    2014-10-01

    We compared the clinical performances of the BacT/Alert Plus (bioMérieux) and Bactec Plus (Becton Dickinson) aerobic and anaerobic blood culture (BC) media with adsorbent polymeric beads. Patients ≥ 16 years old with suspected bloodstream infections (BSIs) were enrolled in intensive care units and infectious disease wards. A single 40-ml blood sample was collected from each and used to inoculate (10 ml/bottle) one set of BacT/Alert Plus cultures and one set of Bactec Plus cultures, each set consisting of one aerobic and one anaerobic bottle. Cultures were incubated ≤ 5 days in the BacT/Alert 3D and Bactec FX instruments, respectively. A total of 128 unique BSI episodes were identified based on the recovery of clinically significant growth in 212 aerobic cultures (106 BacT/Alert and 106 Bactec) and 151 anaerobic cultures (82 BacT/Alert and 69 Bactec). The BacT/Alert aerobic medium had higher recovery rates for Gram-positive cocci (P = 0.024), whereas the Bactec aerobic medium was superior for recovery of Gram-negative bacilli (P = 0.006). BacT/Alert anaerobic medium recovery rates exceeded those of the Bactec anaerobic medium for total organisms (P = 0.003), Gram-positive cocci (P = 0.013), and Escherichia coli (P = 0.030). In terms of capacity for diagnosing the 128 septic episodes, the BacT/Alert and Bactec sets were comparable, although the former sets diagnosed more BSIs caused by Gram-positive cocci (P = 0.008). They also allowed earlier identification of coagulase-negative staphylococcal growth (mean, 2.8 h; P = 0.003) and growth in samples from patients not on antimicrobial therapy that yielded positive results (mean, 1.3 h; P direct matrix-assisted laser desorption ionization-time of flight mass spectrometry assay of BC broths. The BacT/Alert Plus media line appears to be a reliable, timesaving tool for routine detection of BSIs in the population we studied, although further studies are needed to evaluate their performance in other settings. Copyright

  7. Direct quantum mechanical calculation of the F + H{sub 2} {yields} HF + H thermal rate constant

    Energy Technology Data Exchange (ETDEWEB)

    Moix, Marc [Computer Simulation and Modeling (COSMO) Lab, Parc Cientific de Barcelona, Josep Samitier 5, 08028 Barcelona (Spain); Institut de Quimica Teorica i Computacional de la UB (IQTCUB), Universitat de Barcelona (Spain); Huarte-Larranaga, Fermin [Computer Simulation and Modeling (COSMO) Lab, Parc Cientific de Barcelona, Josep Samitier 5, 08028 Barcelona (Spain); Institut de Quimica Teorica i Computacional de la UB (IQTCUB), Universitat de Barcelona (Spain)], E-mail: fhuarte@pcb.ub.es

    2008-07-03

    Accurate full-dimensional quantum mechanical thermal rate constant values have been calculated for the F+H{sub 2}{yields}HF+H reaction on the Stark-Werner ab initio potential energy surface. These calculations are based on a flux correlation functions and employ a rigorous statistical sampling scheme to account for the overall rotation and the MCTDH scheme for the wave packet propagation. Our results shed some light on discrepancies on the thermal rate found for previous flux correlation based calculations with respect to accurate reactive scattering results. The resonance pattern of the all-J cumulative reaction probability is analyzed in terms of the partial wave contributions.

  8. EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

    KAUST Repository

    Piskorz, Danielle; Benneke, Bjö rn; Crockett, Nathan R.; Lockwood, Alexandra C.; Blake, Geoffrey A.; Barman, Travis S.; Bender, Chad F.; Bryan, Marta L.; Carr, John S.; Fischer, Debra A.; Howard, Andrew W.; Isaacson, Howard; Johnson, John A.

    2016-01-01

    We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations

  9. Performance analysis of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

    DEFF Research Database (Denmark)

    Modi, Anish; Haglind, Fredrik

    2014-01-01

    Solar thermal power plants have attracted increasing interest in the past few years - with respect to both the design of the various plant components, and extending the operation hours by employing different types of storage systems. One approach to improve the overall plant efficiency is to use ...

  10. Interlaboratory determinations of isotopically enriched metals by field desorption mass spectroscopy

    International Nuclear Information System (INIS)

    Bahr, U.; Schulten, H.R.; Achenbach, C.; Ziskoven, R.

    1982-01-01

    The isotopic distribution of stable isotopes in six enriched metals (calcium, copper, barium, rubidium, strontium and thallium) has been determined by field desorption mass spectrometry. A first evaluation of the interlaboratory reproducibility of the application of this method for trace determination of metals was made using three different types of mass spectrometers in three different laboratories. The standard deviations for the most abundant isotopes of the metals investigated are between +-0.1 and +-0.5%. Within these standard deviations, the values obtained by the three mass spectrometry groups are the same. To support the accuracy of our quantification, thermal ionization mass spectrometry has been employed and confirms the results of the field desorption method. (orig.) [de

  11. Status of direct containment heating in CSNI member countries. Report of task group on ex-vessel thermal-hydraulics

    International Nuclear Information System (INIS)

    1989-03-01

    The status of activities on direct containment heating in the light water reactor program in OECD/CSNI countries is presented. Experimental and analytical studies are reviewed. Approaches or measures are discussed for accident management in relation to direct containment heating. A discussion is given of common and diverging views among the countries based, in part, on response to a questionnaire. The key issues are discussed and recommendations are provided for future CSNI work on direct containment heating

  12. Testosterone sorption and desorption: Effects of soil particle size

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yong, E-mail: yqi01@unomaha.edu [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Zhang, Tian C. [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Ren, Yongzheng [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-08-30

    Graphical abstract: - Highlights: • Smaller soil particles have higher sorption and lower desorption rates. • The sorption capacity ranks as clay > silt > sand. • Small particles like clays have less potential for desorption. • Colloids (clays) have high potential to facilitate the transport of hormones in soil–water environments. - Abstract: Soils contain a wide range of particles of different diameters with different mobility during rainfall events. Effects of soil particles on sorption and desorption behaviors of steroid hormones have not been investigated. In this study, wet sieve washing and repeated sedimentation methods were used to fractionate the soils into five ranges. The sorption and desorption properties and related mechanisms of testosterone in batch reactors filled with fractionated soil particles were evaluated. Results of sorption and desorption kinetics indicate that small soil particles have higher sorption and lower desorption rates than that of big ones. Thermodynamic results show the sorption processes are spontaneous and exothermal. The sorption capacity ranks as clay > silt > sand, depending mainly on specific surface area and surface functional groups. The urea control test shows that hydrogen bonding contributes to testosterone sorption onto clay and silt but not on sand. Desorption tests indicate sorption is 36–65% irreversible from clay to sand. Clays have highest desorption hysteresis among these five soil fractions, indicating small particles like clays have less potential for desorption. The results provide indirect evidence on the colloid (clay)-facilitated transport of hormones (micro-pollutants) in soil environments.

  13. Helium desorption in EFDA iron materials for use in nuclear fusion reactors

    International Nuclear Information System (INIS)

    Salazar R, A. R.; Pinedo V, J. L.; Sanchez, F. J.; Ibarra, A.; Vila, R.

    2015-09-01

    In this paper the implantation with monoenergetic ions (He + ) was realized with an energy of 5 KeV in iron samples (99.9999 %) EFDA (European Fusion Development Agreement) using a collimated beam, after this a Thermal Desorption Spectrometry of Helium (THeDS) was made using a leak meter that detects amounts of helium of up to 10 - - 12 mbar l/s. Doses with which the implantation was carried out were 2 x 10 15 He + /cm 2 , 1 x 10 16 He + /cm 2 , 2 x 10 16 He + /cm 2 , 1 x 10 17 He + /cm 2 during times of 90 s, 450 s, 900 s and 4500 s, respectively. Also, using the SRIM program was calculated the depth at which the helium ions penetrate the sample of pure ion, finding that the maximum distance is 0.025μm in the sample. For this study, 11 samples of Fe EFDA were prepared to find defects that are caused after implantation of helium in order to provide valuable information to the manufacture of materials for future fusion reactors. However understand the effects of helium in the micro structural evolution and mechanical properties of structural materials are some of the most difficult questions to answer in materials research for nuclear fusion. When analyzing the spectra of THeDS was found that five different groups of desorption peaks existed, which are attributed to defects of He caused in the material, these defects are He n V (2≤n≤6), He n V m , He V for the groups I, II and IV respectively. These results are due to the comparison of the peaks presented in the desorption spectrum of He, with those of other authors who have made theoretical calculations. Is important to note that the thermal desorption spectrum of helium was different depending on the dose with which the implantation of He + was performed. (Author)

  14. Direct synthesis of nano-sized glass powders with spherical shape by RF (radio frequency) thermal plasma

    International Nuclear Information System (INIS)

    Seo, J.H.; Kim, J.S.; Lee, M.Y.; Ju, W.T.; Nam, I.T.

    2011-01-01

    A new route for obtaining very small, spheroid glass powders is demonstrated using an RF (radio frequency) thermal plasma system. During the process, four kinds of chemicals, here SiO 2 , B 2 O 3 , BaCO 3 , and K 2 CO 3 , were mixed at pre-set weight ratios, spray-dried, calcined at 250 deg. C for 3 h, and crushed into fragments. Then, they were successfully reformed into nano-sized amorphous powders (< 200 nm) with spherical shape by injecting them along the centerline of an RF thermal plasma reactor at ∼ 24 kW. The as-synthesized powders show negligible (< 1%) composition changes when compared with the injected precursors of raw material compounds.

  15. Ground Thermal Diffusivity Calculation by Direct Soil Temperature Measurement. Application to very Low Enthalpy Geothermal Energy Systems.

    Science.gov (United States)

    Andújar Márquez, José Manuel; Martínez Bohórquez, Miguel Ángel; Gómez Melgar, Sergio

    2016-02-29

    This paper presents a methodology and instrumentation system for the indirect measurement of the thermal diffusivity of a soil at a given depth from measuring its temperature at that depth. The development has been carried out considering its application to the design and sizing of very low enthalpy geothermal energy (VLEGE) systems, but it can has many other applications, for example in construction, agriculture or biology. The methodology is simple and inexpensive because it can take advantage of the prescriptive geotechnical drilling prior to the construction of a house or building, to take at the same time temperature measurements that will allow get the actual temperature and ground thermal diffusivity to the depth of interest. The methodology and developed system have been tested and used in the design of a VLEGE facility for a chalet with basement at the outskirts of Huelva (a city in the southwest of Spain). Experimental results validate the proposed approach.

  16. A study of thermal deformation in the carriage of a permanent magnet direct drive linear motor stage

    International Nuclear Information System (INIS)

    Chow, J.H.; Zhong, Z.W.; Lin, W.; Khoo, L.P.

    2012-01-01

    Carriage deformation due to temperature gradients within the materials of the carriage affects the accuracy of precision machines. This is largely due to the indeterminist temperature distribution in the carriage's material caused by the non-linearity of heat transfer. The joule heat from the motor coil forms the main heat source. When coupled with the heat loss through convection and radiation, the temperature variation in the motor's carriage also increases. In this study, the Finite Element Analysis was used together with a set of boundary conditions, which was obtained empirically, to analyze the distortion of the motor's carriage. The simulated results were compared with those obtained through experiments. The study shows that it is important to know, rather than to assume, the thermal boundary conditions of the motor's carriage of a precision machine in order to accurately estimate the thermal deformation of the carriage in precision machining. - Highlights: ► Deformation occurs in carriages which are mounted with linear motor. ► The convective coefficient, which is assumed to be 10 W mm −2 , is shown to be invalid. ► The perfect contact conductance is shown to be invalid too. ► To have an accurate thermal model, boundary conditions have to be realistic. ► Boundary conditions are the heat source, convective and conductance values.

  17. Desorption of trihalomethanes in gas liquid contactors

    International Nuclear Information System (INIS)

    Ramirez Quesada, Kenneth

    2000-01-01

    Updated studies show that gastric cancer is related with the existence of trihalomethanes (THMs) in the drinking water. The trihalomethanes are sub products from the degradation of humic acids and your reaction with chlorine and bromine used like decontaminates. The desorption process is used to eliminate the THMs with air in contact with the water. The experimental design was used in three contactors. The contactors selected were: the bubbling's column, the packed column and the shaken tank without screen. There were selected three variable: initial concentration of THMs, the residence time and the turbulence degree (measured with the Reynolds number). The concentrations were made with a gas chromatograph. The objective of this project is to do a comparison with the gas liquid contactors more used in the industrial level to determinate which ones are the best in the desorption process. The conclusion of the experimental design is that the tank is the equipment with the best capacity to eliminate THMs. Too it includes other techniques to eliminate THMs of the water and your treatment [es

  18. Optical detection of CO and CO2 temperature dependent desorption from carbon nanotube clusters

    International Nuclear Information System (INIS)

    Chistiakova, M V; Armani, A M

    2014-01-01

    The development of new materials relies on high precision methods to quantify adsorption/desorption of gases from surfaces. One commonly used approach is temperature programmed desorption spectroscopy. While this approach is very accurate, it requires complex instrumentation, and it is limited to performing experiments under high vacuum, thus restricting experimental scope. An alternative approach is to integrate the surface of interest directly onto a detector face, creating an active substrate. One surface that has applications in numerous areas is the carbon nanotube (CNT). As such, an active substrate that integrates a CNT surface on a sensor and is able to perform measurements in ambient environments will have significant impact. In the present work, we have developed an active substrate that combines an optical sensor with a CNT cluster substrate. The optical sensor is able to accurately probe the temperature dependent desorption of carbon monoxide and carbon dioxide gases from the CNT cluster surface. This active substrate will enable a wide range of temperature dependent desorption measurements to be performed from a scientifically interesting material system. (paper)

  19. Coupled Chiral Structure in Graphene-Based Film for Ultrahigh Thermal Conductivity in Both In-Plane and Through-Plane Directions.

    Science.gov (United States)

    Meng, Xin; Pan, Hui; Zhu, Chengling; Chen, Zhixin; Lu, Tao; Xu, Da; Li, Yao; Zhu, Shenmin

    2018-06-21

    The development of high-performance thermal management materials to dissipate excessive heat both in plane and through plane is of special interest to maintain efficient operation and prolong the life of electronic devices. Herein, we designed and constructed a graphene-based composite film, which contains chiral liquid crystals (cellulose nanocrystals, CNCs) inside graphene oxide (GO). The composite film was prepared by annealing and compacting of self-assembled GO-CNC, which contains chiral smectic liquid crystal structures. The helical arranged nanorods of carbonized CNC act as in-plane connections, which bridge neighboring graphene sheets. More interestingly, the chiral structures also act as through-plane connections, which bridge the upper and lower graphene layers. As a result, the graphene-based composite film shows extraordinary thermal conductivity, in both in-plane (1820.4 W m -1 K -1 ) and through-plane (4.596 W m -1 K -1 ) directions. As a thermal management material, the heat dissipation and transportation behaviors of the composite film were investigated using a self-heating system and the results showed that the real-time temperature of the heater covered with the film was 44.5 °C lower than a naked heater. The prepared film shows a much higher efficiency of heat transportation than the commonly used thermal conductive Cu foil. Additionally, this graphene-based composite film exhibits excellent mechanical strength of 31.6 MPa and an electrical conductivity of 667.4 S cm -1 . The strategy reported here may open a new avenue to the development of high-performance thermal management films.

  20. Solvent jet desorption capillary photoionization-mass spectrometry.

    Science.gov (United States)

    Haapala, Markus; Teppo, Jaakko; Ollikainen, Elisa; Kiiski, Iiro; Vaikkinen, Anu; Kauppila, Tiina J; Kostiainen, Risto

    2015-03-17

    A new ambient mass spectrometry method, solvent jet desorption capillary photoionization (DCPI), is described. The method uses a solvent jet generated by a coaxial nebulizer operated at ambient conditions with nitrogen as nebulizer gas. The solvent jet is directed onto a sample surface, from which analytes are extracted into the solvent and ejected from the surface in secondary droplets formed in collisions between the jet and the sample surface. The secondary droplets are directed into the heated capillary photoionization (CPI) device, where the droplets are vaporized and the gaseous analytes are ionized by 10 eV photons generated by a vacuum ultraviolet (VUV) krypton discharge lamp. As the CPI device is directly connected to the extended capillary inlet of the MS, high ion transfer efficiency to the vacuum of MS is achieved. The solvent jet DCPI provides several advantages: high sensitivity for nonpolar and polar compounds with limit of detection down to low fmol levels, capability of analyzing small and large molecules, and good spatial resolution (250 μm). Two ionization mechanisms are involved in DCPI: atmospheric pressure photoionization, capable of ionizing polar and nonpolar compounds, and solvent assisted inlet ionization capable of ionizing larger molecules like peptides. The feasibility of DCPI was successfully tested in the analysis of polar and nonpolar compounds in sage leaves and chili pepper.

  1. Using SpaceClaimTD Direct for Modeling Components with Complex Geometries for the Thermal Desktop-Based Advanced Stirling Radioisotope Generator Model

    Science.gov (United States)

    Fabanich, William A., Jr.

    2014-01-01

    SpaceClaim/TD Direct has been used extensively in the development of the Advanced Stirling Radioisotope Generator (ASRG) thermal model. This paper outlines the workflow for that aspect of the task and includes proposed best practices and lessons learned. The ASRG thermal model was developed to predict component temperatures and power output and to provide insight into the prime contractor's thermal modeling efforts. The insulation blocks, heat collectors, and cold side adapter flanges (CSAFs) were modeled with this approach. The model was constructed using mostly TD finite difference (FD) surfaces/solids. However, some complex geometry could not be reproduced with TD primitives while maintaining the desired degree of geometric fidelity. Using SpaceClaim permitted the import of original CAD files and enabled the defeaturing/repair of those geometries. TD Direct (a SpaceClaim add-on from CRTech) adds features that allowed the "mark-up" of that geometry. These so-called "mark-ups" control how finite element (FE) meshes are to be generated through the "tagging" of features (e.g. edges, solids, surfaces). These tags represent parameters that include: submodels, material properties, material orienters, optical properties, and radiation analysis groups. TD aliases were used for most tags to allow analysis to be performed with a variety of parameter values. "Domain-tags" were also attached to individual and groups of surfaces and solids to allow them to be used later within TD to populate objects like, for example, heaters and contactors. These tools allow the user to make changes to the geometry in SpaceClaim and then easily synchronize the mesh in TD without having to redefine the objects each time as one would if using TDMesher. The use of SpaceClaim/TD Direct helps simplify the process for importing existing geometries and in the creation of high fidelity FE meshes to represent complex parts. It also saves time and effort in the subsequent analysis.

  2. Using SpaceClaim/TD Direct for Modeling Components with Complex Geometries for the Thermal Desktop-Based Advanced Stirling Radioisotope Generator Model

    Science.gov (United States)

    Fabanich, William

    2014-01-01

    SpaceClaim/TD Direct has been used extensively in the development of the Advanced Stirling Radioisotope Generator (ASRG) thermal model. This paper outlines the workflow for that aspect of the task and includes proposed best practices and lessons learned. The ASRG thermal model was developed to predict component temperatures and power output and to provide insight into the prime contractors thermal modeling efforts. The insulation blocks, heat collectors, and cold side adapter flanges (CSAFs) were modeled with this approach. The model was constructed using mostly TD finite difference (FD) surfaces solids. However, some complex geometry could not be reproduced with TD primitives while maintaining the desired degree of geometric fidelity. Using SpaceClaim permitted the import of original CAD files and enabled the defeaturing repair of those geometries. TD Direct (a SpaceClaim add-on from CRTech) adds features that allowed the mark-up of that geometry. These so-called mark-ups control how finite element (FE) meshes were generated and allowed the tagging of features (e.g. edges, solids, surfaces). These tags represent parameters that include: submodels, material properties, material orienters, optical properties, and radiation analysis groups. TD aliases were used for most tags to allow analysis to be performed with a variety of parameter values. Domain-tags were also attached to individual and groups of surfaces and solids to allow them to be used later within TD to populate objects like, for example, heaters and contactors. These tools allow the user to make changes to the geometry in SpaceClaim and then easily synchronize the mesh in TD without having to redefine these objects each time as one would if using TD Mesher.The use of SpaceClaim/TD Direct has helped simplify the process for importing existing geometries and in the creation of high fidelity FE meshes to represent complex parts. It has also saved time and effort in the subsequent analysis.

  3. The Marangoni convection induced by acetone desorption from the falling soap film

    Science.gov (United States)

    Sha, Yong; Li, Zhangyun; Wang, Yongyi; Huang, Jiali

    2012-05-01

    By means of the falling soap film tunnel and the Schlieren optical method, the Marangoni convection were observed directly in the immediate interfacial neighborhood during the desorption process of acetone from the falling soap film. Moreover, the hydraulic characteristics of the falling soap film tunnel, the acetone concentration, the surface tension of the soap liquid and the mass transfer has been investigated in details through the experimental or theoretical method.

  4. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    International Nuclear Information System (INIS)

    Cooper, J.F.; Ballazs G.B.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput

  5. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput.

  6. Modeling Organic Contaminant Desorption from Municipal Solid Waste Components

    Science.gov (United States)

    Knappe, D. R.; Wu, B.; Barlaz, M. A.

    2002-12-01

    Approximately 25% of the sites on the National Priority List (NPL) of Superfund are municipal landfills that accepted hazardous waste. Unlined landfills typically result in groundwater contamination, and priority pollutants such as alkylbenzenes are often present. To select cost-effective risk management alternatives, better information on factors controlling the fate of hydrophobic organic contaminants (HOCs) in landfills is required. The objectives of this study were (1) to investigate the effects of HOC aging time, anaerobic sorbent decomposition, and leachate composition on HOC desorption rates, and (2) to simulate HOC desorption rates from polymers and biopolymer composites with suitable diffusion models. Experiments were conducted with individual components of municipal solid waste (MSW) including polyvinyl chloride (PVC), high-density polyethylene (HDPE), newsprint, office paper, and model food and yard waste (rabbit food). Each of the biopolymer composites (office paper, newsprint, rabbit food) was tested in both fresh and anaerobically decomposed form. To determine the effects of aging on alkylbenzene desorption rates, batch desorption tests were performed after sorbents were exposed to toluene for 30 and 250 days in flame-sealed ampules. Desorption tests showed that alkylbenzene desorption rates varied greatly among MSW components (PVC slowest, fresh rabbit food and newsprint fastest). Furthermore, desorption rates decreased as aging time increased. A single-parameter polymer diffusion model successfully described PVC and HDPE desorption data, but it failed to simulate desorption rate data for biopolymer composites. For biopolymer composites, a three-parameter biphasic polymer diffusion model was employed, which successfully simulated both the initial rapid and the subsequent slow desorption of toluene. Toluene desorption rates from MSW mixtures were predicted for typical MSW compositions in the years 1960 and 1997. For the older MSW mixture, which had a

  7. Copper desorption from Gelidium algal biomass.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2007-04-01

    Desorption of divalent copper from marine algae Gelidium sesquipedale, an algal waste (from agar extraction industry) and a composite material (the algal waste immobilized in polyacrylonitrile) was studied in a batch system. Copper ions were first adsorbed until saturation and then desorbed by HNO(3) and Na(2)EDTA solutions. Elution efficiency using HNO(3) increases as pH decreases. At pH=1, for a solid to liquid ratio S/L=4gl(-1), elution efficiency was 97%, 95% and 88%, the stoichiometric coefficient for the ionic exchange, 0.70+/-0.02, 0.73+/-0.05 and 0.76+/-0.06 and the selectivity coefficient, 0.93+/-0.07, 1.0+/-0.3 and 1.1+/-0.3, respectively, for algae Gelidium, algal waste and composite material. Complexation of copper ions by EDTA occurs in a molar proportion of 1:1 and the elution efficiency increases with EDTA concentration. For concentrations of 1.4, 0.88 and 0.57 mmoll(-1), the elution efficiency for S/L=4gl(-1), was 91%, 86% and 78%, respectively, for algae Gelidium, algal waste and composite material. The S/L ratio, in the range 1-20gl(-1), has little influence on copper recovery by using 0.1M HNO(3). Desorption kinetics was very fast for all biosorbents. Kinetic data using HNO(3) as eluant were well described by the mass transfer model, considering the average metal concentration in the solid phase and the equilibrium relationship given by the mass action law. The homogeneous diffusion coefficient varied between 1.0 x 10(-7)cm(2)s(-1) for algae Gelidium and 3.0 x 10(-7)cm(2)s(-1) for the composite material.

  8. Brominated Tyrosine and Polyelectrolyte Multilayer Analysis by Laser Desorption VUV Postionization and Secondary Ion Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    University of Illinois at Chicago; Blaze, Melvin M. T.; Takahashi, Lynelle; Zhou, Jia; Ahmed, Musahid; Gasper, Gerald; Pleticha, F. Douglas; Hanley, Luke

    2011-03-14

    The small molecular analyte 3,5-dibromotyrosine (Br2Y) and chitosan-alginate polyelectrolyte multilayers (PEM) with and without adsorbed Br2Y were analyzed by laser desorption postionization mass spectrometry (LDPI-MS). LDPI-MS using 7.87 eV laser and tunable 8 ? 12.5 eV synchrotron vacuum ultraviolet (VUV) radiation found that desorption of clusters from Br2Y films allowed detection by≤8 eV single photon ionization. Thermal desorption and electronic structure calculations determined the ionization energy of Br2Y to be ~;;8.3?0.1 eV and further indicated that the lower ionization energies of clusters permitted their detection at≤8 eV photon energies. However, single photon ionization could only detect Br2Y adsorbed within PEMs when using either higher photon energies or matrix addition to the sample. All samples were also analyzed by 25 keV Bi3 + secondary ion mass spectrometry (SIMS), with the negative ion spectra showing strong parent ion signal which complemented that observed by LDPI-MS. The negative ion SIMS depended strongly on the high electron affinity of this specific analyte and the analyte?s condensed phase environment.

  9. Searching out the hydrogen absorption/desorption limiting reaction factors: Strategies allowing to increase kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Zeaiter, Ali, E-mail: ali.zeaiter@femto-st.fr; Chapelle, David; Nardin, Philippe

    2015-10-05

    Highlights: • A macro scale thermodynamic model that simulates the response of a FeTi-X hydride tank is performed, and validated experimentally. • A sensibility study to identify the most influent input variables that can changes very largely the reaction rate. - Abstract: Hydrogen gas has become one of the most promising energy carriers. Main breakthrough concerns hydrogen solid storage, specially based on intermetallic material use. Regarding the raw material abundance and cost, the AB type alloy FeTi is an auspicious candidate to store hydrogen. Its absorption/desorption kinetics is a basic hindrance to common use, compared with more usual hydrides. First, discussions based on literature help us identifying the successive steps leading to metal hydriding, and allow to introduce the physical parameters which drive or limit the reaction. This analysis leads us to suggest strategies in order to increase absorption/desorption kinetics. Attention is then paid to a thermofluidodynamic model, allowing to describe a macroscopic solid storage reactor. Thus, we can achieve a simulation which describes the overall reaction inside the hydrogen reactor and, by varying the sub-mentioned parameters (thermal conductivity, the powder granularity, environment heat exchange…), we attempt to hierarchy the reaction limiting factors. These simulations are correlated to absorption/desorption experiments for which pressure, temperature and hydrogen flow are recorded.

  10. Combined effects of cooled EGR and a higher geometric compression ratio on thermal efficiency improvement of a downsized boosted spark-ignition direct-injection engine

    International Nuclear Information System (INIS)

    Su, Jianye; Xu, Min; Li, Tie; Gao, Yi; Wang, Jiasheng

    2014-01-01

    Highlights: • Experiments for the effects of cooled EGR and two compression ratios (CR) on fuel efficiency were conducted. • The mechanism for the observed fuel efficiency behaviors by cooled EGR and high CR was clarified. • Cooled EGR offers more fuel efficiency improvement than elevating CR from 9.3 to 10.9. • Combining 18–25% cooled EGR with 10.9 CR lead to 2.1–3.5% brake thermal efficiency improvements. - Abstract: The downsized boosted spark-ignition direct-injection (SIDI) engine has proven to be one of the most promising concepts to improve vehicle fuel economy. However, the boosted engine is typically designed at a lower geometric compression ratio (CR) due to the increased knock tendency in comparison to naturally aspirated engines, limiting the potential of improving fuel economy. On the other hand, cooled exhaust gas recirculation (EGR) has drawn attention due to the potential to suppress knock and improve fuel economy. Combing the effects of boosting, increased CR and cooled EGR to further improve fuel economy within acceptable knock tolerance has been investigated using a 2.0 L downsized boosted SIDI engine over a wide range of engine operating conditions from 1000 rpm to 3000 rpm at low to high loads. To clarify the mechanism of this complicated effects, the first law of thermodynamics analysis was conducted with the inputs from GT-Power® engine simulation. Experiment results indicate that cooled EGR provides more brake thermal efficiency improvement than increasing geometric CR from 9.3 to 10.9. The benefit of brake thermal efficiency from the higher CR is limited to low load conditions. The attributes for improving brake thermal efficiency by cooled EGR include reduced heat transfer loss, reduced pumping work and increased ratio of specific heats for all the engine operating conditions, as well as higher degree of constant volume heat release only for the knock-limited high load conditions. The combined effects of 18–25% cooled EGR

  11. Is there a difference between the energy and CO_2 emission performance for China’s thermal power industry? A bootstrapped directional distance function approach

    International Nuclear Information System (INIS)

    Duan, Na; Guo, Jun-Peng; Xie, Bai-Chen

    2016-01-01

    Highlights: • Evaluate the energy and CO_2 emission performance of China’s thermal power industry. • Perform statistical inferences for the estimates of efficiency and productivity indexes. • There exist differences between the energy and CO_2 emission performance. • Technological progress is the main driving force for productivity improvement. - Abstract: A scientific evaluation of the energy efficiency and CO_2 emission performance of the thermal power industry could not only provide valuable information for reducing energy consumption and carbon emissions but also serve as a tool to estimate the effectiveness of relevant policy reforms. Considering the opposite effects of energy conservation and carbon emission reduction on generation cost, this study respectively measures the energy and CO_2 emission performance of the thermal power industries in China’s 30 provincial administrative regions during the period 2005–2012 from both static and dynamic perspectives. We implement the bootstrap method for the directional distance function to correct the possible estimate bias and test the significance of productivity changes where the weak disposability of undesirable outputs is also integrated. The empirical analysis leads to the following conclusions. The bootstrapping results could provide us with much valuable information because the initial estimates might result from sampling noise rather than reveal the real variations. In addition, some differences do exist between the energy and CO_2 emission performance of China’s thermal power industry. Furthermore, technological progress is the main driving force for energy and CO_2 emission productivity improvement and it works better for the former.

  12. Effects of Molybdenum Addition on Hydrogen Desorption of TiC Precipitation-Hardened Steel

    Science.gov (United States)

    Song, Eun Ju; Baek, Seung-Wook; Nahm, Seung Hoon; Suh, Dong-Woo

    2018-03-01

    The hydrogen-trap states in TiC and MoC that have coherent interfaces with ferrite were investigated using first-principles calculation. The trapping sites of TiC were the interfaces and interstitial sites of ferrite. On the other hand, the trapping sites of MoC were ferrite interstitial sites; the interface had a negative binding energy with H. Thermal desorption analysis confirms that the amounts of diffusible hydrogen were significantly reduced by addition of Mo in Ti-bearing steel.

  13. Innovative direct energy conversion systems from fusion output thermal power to the electrical one with the use of electronic adiabatic processes of electron fluid in solid conductors

    International Nuclear Information System (INIS)

    Kondoh, Y.; Kondo, M.; Shimoda, K.; Takahashi, T.; Osuga, K.

    2003-07-01

    It is shown that with the use of the fusion output and/or environmental thermal energy, innovative open systems for permanent auto-working (PA) direct energy converting (DEC) from the thermal to the electrical (TE) and further to the chemical potential (TEC) energies, abbreviated as PA-TEC-DEC systems, can be used for new auto-working electrical power plants and the plants of the compressible and conveyable hydrogen gas resources at various regions in the whole world. It is analytically shown that the same physical mechanism by free electrons and electrical potential determined by temperature in conductors, which include semiconductors, leads to the Peltier effect and the Seebeck one. It is analytically proved that the energy conservation law is exactly satisfied in a simple form where the net absorbed thermal power is directly transferred to the electrical power and to the chemical power in the PA-TEC-DEC systems. It is analytically and experimentally clarified that the long distance separation between two π type elements of the heat absorption side and the production one of the Peltier effect circuit system or between the higher temperature side and the lower one of the Seebeck effect circuit one does not change mechanisms of the heat pumping by the Peltier effect and of the TE-DEC by the Seebeck effect. The proposed systems gives us freedom of no using the fossil fuel, such as coals, oils, and natural gases that yield serious greenhouse effect all over the earth, and the plant of nuclear fissions that left radiating wastes, i.e., no more environmental pollutions. The PA-TEC-DEC systems can be applicable for several km scale systems to the micro ones, such as the plants of the electrical power and the hydrogen gas resources, compact transportable hydrogen gas producers, the refrigerators, the air conditions, home electrical apparatuses, and further the computer elements. (author)

  14. Electron beam exposure mechanisms in hydrogen silsesquioxane investigated by vibrational spectroscopy and in-situ electron beam induced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Olynick, D.L.; Cord, B.; Schipotinin, A.; Ogletree, D.F.; Schuck, P.J.

    2009-11-13

    Hydrogen Silsesquioxane (HSQ) is used as a high-resolution resist with resolution down below 10nm half-pitch. This material or materials with related functionalities could have widespread impact in nanolithography and nanoscience applications if the exposure mechanism was understood and instabilities controlled. Here we have directly investigated the exposure mechanism using vibrational spectroscopy (both Raman and Fourier transform Infrared) and electron beam desorption spectrocscopy (EBDS). In the non-networked HSQ system, silicon atoms sit at the corners of a cubic structure. Each silicon is bonded to a hydrogen atom and bridges 3 oxygen atoms (formula: HSiO3/2). For the first time, we have shown, via changes in the Si-H2 peak at ~;;2200 cm -1 in the Raman spectra and the release of SiHx products in EBID, that electron-bam exposed materials crosslinks via a redistribution reaction. In addition, we observe the release of significantly more H2 than SiH2 during EBID, which is indicative of additional reaction mechanisms. Additionally, we compare the behavior of HSQ in response to both thermal and electron-beam induced reactions.

  15. Use of stable sulphur isotopes to monitor directly the behaviour of sulphur in coal during thermal desulphurization

    Science.gov (United States)

    Liu, Chao-Li; Hackley, Keith C.; Coleman, D.D.

    1987-01-01

    A method has been developed using stable sulphur isotope analyses to monitor the behaviour of sulphur forms in a coal during thermal desulphurization. In this method, the natural stable isotopic composition of the pyritic and organic sulphur in coal is used as a tracer to follow their mobility during the desulphurization process. This tracer method is based on the fact that the isotopic compositions of pyritic and organic sulphur are significantly different in some coals. Isotopic results of pyrolysis experiments at temperatures ranging from 350 to 750 ??C indicate that the sulphur released with the volatiles is predominantly organic sulphur. The pyritic sulphur is evolved in significant quantities only when pyrolysis temperatures exceed 500 ??C. The presence of pyrite seems to have no effect on the amount of organic sulphur evolved during pyrolysis. The chemical and isotopic mass balances achieved from three different samples of the Herrin (No. 6) coal of the Illinois Basin demonstrate that this stable isotope tracer method is quantitative. The main disadvantage of this tracing technique is that not all coals contain isotopically distinct organic and pyritic sulphur. ?? 1987.

  16. Drawing a different picture with pencil lead as matrix-assisted laser desorption/ionization matrix for fullerene derivatives.

    Science.gov (United States)

    Nye, Leanne C; Hungerbühler, Hartmut; Drewello, Thomas

    2018-02-01

    Inspired by reports on the use of pencil lead as a matrix-assisted laser desorption/ionization matrix, paving the way towards matrix-free matrix-assisted laser desorption/ionization, the present investigation evaluates its usage with organic fullerene derivatives. Currently, this class of compounds is best analysed using the electron transfer matrix trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene] malononitrile (DCTB), which was employed as the standard here. The suitability of pencil lead was additionally compared to direct (i.e. no matrix) laser desorption/ionization-mass spectrometry. The use of (DCTB) was identified as the by far gentler method, producing spectra with abundant molecular ion signals and much reduced fragmentation. Analytically, pencil lead was found to be ineffective as a matrix, however, appears to be an extremely easy and inexpensive method for producing sodium and potassium adducts.

  17. Damage, trapping and desorption at the implantation of helium and deuterium in graphite, diamond and silicon carbide

    International Nuclear Information System (INIS)

    Lopez, G.A.R.

    1995-07-01

    The production, thermal stability and structure of ion induced defects have been studied by Rutherford backscattering in channeling geometry for the implantation of helium and deuterium in graphite, diamond and silicon carbide with energies of 8 and 20 keV. At the implantation of deuterium and helium ions more defects were measured in graphite than in diamond or silicon carbide at equal experimental conditions. This is due to increased backscattering in graphite, which is caused by the splitting and tilting of crystallites and a local reordering of lattice atoms around defects. At 300 K, Helium produces more defects in all three materials than deuterium with equal depth distribution of defects. The ratio of the defects produced by helium and deuterium agrees very well with the corresponding ratio of the energy deposited in nuclear collisions. In graphite, only small concentrations of deuterium induced defects anneal below 800 K, while in diamond small concentrations of deuterium as well as of helium induced defects anneal mostly below 800 K. This annealing behavior is considered to be due to recombination of point defects. The buildup of helium and deuterium in graphite is different. The trapping of deuterium proceeds until saturation is reached, while in the case of helium trapping is interrupted by flaking. In diamond, deuterium as well as helium are trapped almost completely until at higher fluences reemission starts and saturation is reached. Two desorption mechanisms were identified for the thermal desorption of helium from base-oriented graphite. Helium implanted at low fluences desorbs diffusing to the surface, while for the implantation of high fluences the release of helium due to blistering dominates. The desorption of deuterium from graphite and diamond shows differences. While in graphite the desorption starts already at 800 K, in diamond up to 1140 K only little desorption can be observed. These differences can be explained by the different transport

  18. The path to clean energy: direct coupling of nuclear and renewable technologies for thermal and electrical applications

    Energy Technology Data Exchange (ETDEWEB)

    Bragg-Sitton, Shannon [Idaho National Lab. (INL), Idaho Falls, ID (United States). Nuclear Fuel Performance and Design; Boardman, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States). Advanced Process and Decision Systems; Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States). Strategic Energy Analysis Center

    2015-07-01

    The U.S. Department of Energy (DOE) recognizes the need to transform the energy infrastructure of the U.S. and elsewhere to systems that can significantly reduce environmental impacts in an efficient and economically viable manner while utilizing both clean energy generation sources and hydrocarbon resources. Thus, DOE is supporting research and development that could lead to more efficient utilization of clean nuclear and renewable energy generation sources. A concept being advanced by the DOE Offices of Nuclear Energy (NE) and Energy Efficiency and Renewable Energy (EERE) is tighter coupling of nuclear and renewable energy sources in a manner that better optimizes energy use for the combined electricity, industrial manufacturing, and the transportation sectors. This integration concept has been referred to as a “hybrid system” that is capable of providing energy (thermal or electrical) where it is needed, when it is needed. For the purposes of this work, the hybrid system would integrate two or more energy resources to generate two or more products, one of which must be an energy commodity, such as electricity or transportation fuel. This definition requires coupling of subsystems ‘‘behind’’ the electrical transmission bus, where energy flows are dynamically apportioned as necessary to meet demand and the system has a single connection to the grid that provides dispatchable electricity as required while capital intensive generation assets operate at full capacity. Development of integrated energy systems for an “energy park” must carefully consider the intended location and the associated regional resources, traditional industrial processes, energy delivery infrastructure, and markets to identify viable region-specific system configurations. This paper will provide an overview of the current status of regional hybrid energy system design, development and application of dynamic analysis tools to assess technical and economic performance, and

  19. Sorption and desorption of diuron in Oxisol under biochar application

    OpenAIRE

    Petter, Fabiano André; Ferreira, Tamara Santos; Sinhorin, Adilson Paulo; Lima, Larissa Borges de; Morais, Leidimar Alves de; Pacheco, Leandro Pereira

    2016-01-01

    ABSTRACT The objective of this study was to verify the kinetics of sorption and desorption of diuron in an Oxisol under application of biochar. The samples were collected in a field experiment conducted in randomized design blocks consisted of 2 base fertilization levels (0 and 400 kg∙ha−1 NPK 00-20-20 fertilizer formula) and 3 doses of biochar (0, 8 and 16 Mg∙ha−1). In the evaluation of sorption and desorption, Batch Equilibrium method was used. The kinetics of sorption and desorption of diu...

  20. Acoustic emission during hydrogen absorption and desorption in palladium

    International Nuclear Information System (INIS)

    Ramesh, R.; Mukhopadhyay, C.K.; Jayakumar, T.; Baldev Raj

    1996-01-01

    Acoustic emission technique has been used to study charging and discharging of hydrogen in palladium. During charging, breaking of oxide film due to surface activation and saturation of hydrogen absorption have been identified by acoustic emission. In the discharging cycle, the desorption of hydrogen from the specimen leads to high AE activity immediately after initiation of discharging, followed by gradual decrease in the acoustic activity, which reaches a minimum upon completion of the desorption. The potential of the acoustic emission technique for studying the kinetics of hydrogen absorption and desorption in metals has been shown. (author)

  1. Inelastic surface collisions and the desorption of massive molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Macfarlane, R D [Texas A and M Univ., College Station (USA). Dept. of Chemistry

    1983-01-01

    The interaction of high energy ions in the region of electronic stopping (1 MeV u/sup -1/) stimulates the desorption of massive molecular ions of biomolecules such as insulin. The experimental details of the measurements are given with some examples of application for analytical mass spectrometry. Studies on the role of the incident ion (accelerator beam experiments) are reviewed as well as the contribution of the matrix to the desorption-ionization process. How the electronic relaxation process couples to desorption-ionization is a central question in understanding the overall mechanism of the process.

  2. Laser desorption/ionization from nanostructured surfaces: nanowires, nanoparticle films and silicon microcolumn arrays

    International Nuclear Information System (INIS)

    Chen Yong; Luo Guanghong; Diao Jiajie; Chornoguz, Olesya; Reeves, Mark; Vertes, Akos

    2007-01-01

    Due to their optical properties and morphology, thin films formed of nanoparticles are potentially new platforms for soft laser desorption/ionization (SLDI) mass spectrometry. Thin films of gold nanoparticles (with 12±1 nm particle size) were prepared by evaporation-driven vertical colloidal deposition and used to analyze a series of directly deposited polypeptide samples. In this new SLDI method, the required laser fluence for ion detection was equal or less than what was needed for matrix-assisted laser desorption/ionization (MALDI) but the resulting spectra were free of matrix interferences. A silicon microcolumn array-based substrate (a.k.a. black silicon) was developed as a new matrix-free laser desorption ionization surface. When low-resistivity silicon wafers were processed with a 22 ps pulse length 3xω Nd:YAG laser in air, SF 6 or water environment, regularly arranged conical spikes emerged. The radii of the spike tips varied with the processing environment, ranging from approximately 500 nm in water, to ∼2 μm in SF 6 gas and to ∼5 μm in air. Peptide mass spectra directly induced by a nitrogen laser showed the formation of protonated ions of angiotensin I and II, substance P, bradykinin fragment 1-7, synthetic peptide, pro14-arg, and insulin from the processed silicon surfaces but not from the unprocessed areas. Threshold fluences for desorption/ionization were similar to those used in MALDI. Although compared to silicon nanowires the threshold laser pulse energy for ionization is significantly (∼10x) higher, the ease of production and robustness of microcolumn arrays offer complementary benefits

  3. Simulation of thermal fluid dynamics in parabolic trough receiver tubes with direct steam generation using the computer code ATHLET

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Alexander; Merk, Bruno [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany); Hirsch, Tobias; Pitz-Paal, Robert [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Solarforschung

    2014-06-15

    In the present feasibility study the system code ATHLET, which originates from nuclear engineering, is applied to a parabolic trough test facility. A model of the DISS (DIrect Solar Steam) test facility at Plataforma Solar de Almeria in Spain is assembled and the results of the simulations are compared to measured data and the simulation results of the Modelica library 'DissDyn'. A profound comparison between ATHLET Mod 3.0 Cycle A and the 'DissDyn' library reveals the capabilities of these codes. The calculated mass and energy balance in the ATHLET simulations are in good agreement with the results of the measurements and confirm the applicability for thermodynamic simulations of DSG processes in principle. Supplementary, the capabilities of the 6-equation model with transient momentum balances in ATHLET are used to study the slip between liquid and gas phases and to investigate pressure wave oscillations after a sudden valve closure. (orig.)

  4. Interaction of D2 with H2O amorphous ice studied by temperature-programmed desorption experiments.

    Science.gov (United States)

    Amiaud, L; Fillion, J H; Baouche, S; Dulieu, F; Momeni, A; Lemaire, J L

    2006-03-07

    The gas-surface interaction of molecular hydrogen D2 with a thin film of porous amorphous solid water (ASW) grown at 10 K by slow vapor deposition has been studied by temperature-programmed-desorption (TPD) experiments. Molecular hydrogen diffuses rapidly into the porous network of the ice. The D2 desorption occurring between 10 and 30 K is considered here as a good probe of the effective surface of ASW interacting with the gas. The desorption kinetics have been systematically measured at various coverages. A careful analysis based on the Arrhenius plot method has provided the D2 binding energies as a function of the coverage. Asymmetric and broad distributions of binding energies were found, with a maximum population peaking at low energy. We propose a model for the desorption kinetics that assumes a complete thermal equilibrium of the molecules with the ice film. The sample is characterized by a distribution of adsorption sites that are filled according to a Fermi-Dirac statistic law. The TPD curves can be simulated and fitted to provide the parameters describing the distribution of the molecules as a function of their binding energy. This approach contributes to a correct description of the interaction of molecular hydrogen with the surface of possibly porous grain mantles in the interstellar medium.

  5. Zero-Headspace Coal-Core Gas Desorption Canister, Revised Desorption Data Analysis Spreadsheets and a Dry Canister Heating System

    Science.gov (United States)

    Barker, Charles E.; Dallegge, Todd A.

    2005-01-01

    Coal desorption techniques typically use the U.S. Bureau of Mines (USBM) canister-desorption method as described by Diamond and Levine (1981), Close and Erwin (1989), Ryan and Dawson (1993), McLennan and others (1994), Mavor and Nelson (1997) and Diamond and Schatzel (1998). However, the coal desorption canister designs historically used with this method have an inherent flaw that allows a significant gas-filled headspace bubble to remain in the canister that later has to be compensated for by correcting the measured desorbed gas volume with a mathematical headspace volume correction (McLennan and others, 1994; Mavor and Nelson, 1997).

  6. Strong influence of coadsorbate interaction on CO desorption dynamics on Ru(0001) probed by ultrafast x-ray spectroscopy and ab initio simulations

    Energy Technology Data Exchange (ETDEWEB)

    Xin, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Oberg, H. [Stockholm Univ., Stockholm (Sweden); Beye, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Dell' Angela, M. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Turner, J. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gladh, J. [Stockholm Univ., Stockholm (Sweden); Ng, M. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Sellberg, J. A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Kaya, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mercurio, G. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Hieke, F. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Nordlund, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Schlotter, W. F. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dakovski, G. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Minitti, M. P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fohlisch, A. [Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Univ. Potsdam, Potsdam (Germany); Wolf, M. [Fritz-Haber Institute of the Max-Planck-Society, Berlin (Germany); Wurth, W. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); DESY Photon Science, Hamburg (Germany); Ogasawara, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Norskov, J. K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Ostrom, H. [Stockholm Univ., Stockholm (Sweden); Pettersson, L. G. M. [Stockholm Univ., Stockholm (Sweden); Nilsson, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stockholm Univ., Stockholm (Sweden); Ablid-Pedersen, F. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-04-16

    We show that coadsorbed oxygen atoms have a dramatic influence on the CO desorption dynamics from Ru(0001). In contrast to the precursor-mediated desorption mechanism on Ru(0001), the presence of surface oxygen modifies the electronic structure of Ru atoms such that CO desorption occurs predominantly via the direct pathway. This phenomenon is directly observed in an ultrafast pump-probe experiment using a soft x-ray free-electron laser to monitor the dynamic evolution of the valence electronic structure of the surface species. This is supported with the potential of mean force along the CO desorption path obtained from density-functional theory calculations. Charge density distribution and frozen-orbital analysis suggest that the oxygen-induced reduction of the Pauli repulsion, and consequent increase of the dative interaction between the CO 5σ and the charged Ru atom, is the electronic origin of the distinct desorption dynamics. Ab initio molecular dynamics simulations of CO desorption from Ru(0001) and oxygen-coadsorbed Ru(0001) provide further insights into the surface bond-breaking process.

  7. Mechanism and comparison of needle-type non-thermal direct and indirect atmospheric pressure plasma jets on the degradation of dyes

    Science.gov (United States)

    Attri, Pankaj; Yusupov, Maksudbek; Park, Ji Hoon; Lingamdinne, Lakshmi Prasanna; Koduru, Janardhan Reddy; Shiratani, Masaharu; Choi, Eun Ha; Bogaerts, Annemie

    2016-10-01

    Purified water supply for human use, agriculture and industry is the major global priority nowadays. The advanced oxidation process based on atmospheric pressure non-thermal plasma (NTP) has been used for purification of wastewater, although the underlying mechanisms of degradation of organic pollutants are still unknown. In this study we employ two needle-type atmospheric pressure non-thermal plasma jets, i.e., indirect (ID-APPJ) and direct (D-APPJ) jets operating at Ar feed gas, for the treatment of methylene blue, methyl orange and congo red dyes, for two different times (i.e., 20 min and 30 min). Specifically, we study the decolorization/degradation of all three dyes using the above mentioned plasma sources, by means of UV-Vis spectroscopy, HPLC and a density meter. We also employ mass spectroscopy to verify whether only decolorization or also degradation takes place after treatment of the dyes by the NTP jets. Additionally, we analyze the interaction of OH radicals with all three dyes using reactive molecular dynamics simulations, based on the density functional-tight binding method. This investigation represents the first report on the degradation of these three different dyes by two types of NTP setups, analyzed by various methods, and based on both experimental and computational studies.

  8. SEM method for direct visual tracking of nanoscale morphological changes of platinum based electrocatalysts on fixed locations upon electrochemical or thermal treatments

    Energy Technology Data Exchange (ETDEWEB)

    Zorko, Milena [National Institute of Chemistry, Hajdrihova 19, Ljubljana (Slovenia); Centre of Excellence for Low-Carbon Technologies, Hajdrihova 19, Ljubljana (Slovenia); Jozinović, Barbara [Centre of Excellence for Low-Carbon Technologies, Hajdrihova 19, Ljubljana (Slovenia); Bele, Marjan [National Institute of Chemistry, Hajdrihova 19, Ljubljana (Slovenia); Centre of Excellence for Low-Carbon Technologies, Hajdrihova 19, Ljubljana (Slovenia); Hodnik, Nejc, E-mail: nejc.hodnik@ki.si [National Institute of Chemistry, Hajdrihova 19, Ljubljana (Slovenia); Gaberšček, Miran [National Institute of Chemistry, Hajdrihova 19, Ljubljana (Slovenia); Centre of Excellence for Low-Carbon Technologies, Hajdrihova 19, Ljubljana (Slovenia)

    2014-05-01

    A general method for tracking morphological surface changes on a nanometer scale with scanning electron microscopy (SEM) is introduced. We exemplify the usefulness of the method by showing consecutive SEM images of an identical location before and after the electrochemical and thermal treatments of platinum-based nanoparticles deposited on a high surface area carbon. Observations reveal an insight into platinum based catalyst degradation occurring during potential cycling treatment. The presence of chloride clearly increases the rate of degradation. At these conditions the dominant degradation mechanism seems to be the platinum dissolution with some subsequent redeposition on the top of the catalyst film. By contrast, at the temperature of 60 °C, under potentiostatic conditions some carbon corrosion and particle aggregation was observed. Temperature treatment simulating the annealing step of the synthesis reveals sintering of small platinum based composite aggregates into uniform spherical particles. The method provides a direct proof of induced surface phenomena occurring on a chosen location without the usual statistical uncertainty in usual, random SEM observations across relatively large surface areas. - Highlights: • A new SEM method for observations of identical locations. • Nanoscale morphological consecutive changes on identical locations. • Electrochemical and thermal treatments on platinum based nanoparticles. • Potential cycling induces platinum dissolution with redeposition on top of the film. • At 1.4 V vs. RHE and 60 °C carbon corrosion and particle aggregation is observed.

  9. Poiseuille, thermal transpiration and Couette flows of a rarefied gas between plane parallel walls with nonuniform surface properties in the transverse direction and their reciprocity relations

    Science.gov (United States)

    Doi, Toshiyuki

    2018-04-01

    Slow flows of a rarefied gas between two plane parallel walls with nonuniform surface properties are studied based on kinetic theory. It is assumed that one wall is a diffuse reflection boundary and the other wall is a Maxwell-type boundary whose accommodation coefficient varies periodically in the direction perpendicular to the flow. The time-independent Poiseuille, thermal transpiration and Couette flows are considered. The flow behavior is numerically studied based on the linearized Bhatnagar-Gross-Krook-Welander model of the Boltzmann equation. The flow field, the mass and heat flow rates in the gas, and the tangential force acting on the wall surface are studied over a wide range of the gas rarefaction degree and the parameters characterizing the distribution of the accommodation coefficient. The locally convex velocity distribution is observed in Couette flow of a highly rarefied gas, similarly to Poiseuille flow and thermal transpiration. The reciprocity relations are numerically confirmed over a wide range of the flow parameters.

  10. PAHs soil decontamination in two steps: desorption and electrochemical treatment.

    Science.gov (United States)

    Alcántara, M Teresa; Gómez, Jose; Pazos, Marta; Sanromán, M Angeles

    2009-07-15

    The presence of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in soils poses a potential threat to human health if exposure levels are too high. Nevertheless, the removal of these contaminants presents a challenge to scientists and engineers. The high hydrophobic nature of PAHs enables their strong sorption onto soil or sediments. Thus, the use of surfactants could favour the release of sorbed hydrophobic organic compounds from contaminated soils. In this work, five surfactants, namely Brij 35, Tergitol NP10, Tween 20, Tween 80 and Tyloxapol, are evaluated on the desorption of PAHs [benzanthracene (BzA), fluoranthene (FLU), and pyrene (PYR), single and in mixture] from a model sample such as kaolin. In all cases, the best results were obtained when Tween 80 was employed. In order to obtain the global decontamination of PAHs, their electrochemical degradation is investigated. It is concluded that the order of increasing degradation for single compounds is BzA>FLU>PYR when they are subject to the same electrochemical treatment. In addition, there is a direct relationship between the ionization potential and the electrochemical degradation of PAH.

  11. Laser desorption mass spectrometry for fast DNA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.H.; Ch`ang, L.Y.; Taranenko, N.I.; Allman, S.L.; Tang, K.; Matteson, K.J.

    1995-09-01

    During the past few years, major effort has been directed toward developing mass spectrometry to measure biopolymers because of the great potential benefit to biomedical research. Hellenkamp and his co-workers were the first to report that large polypeptide molecules can be ionized and detected without significant fragmentation when a greater number of nicotinic acid molecules are used as a matrix. This method is now well known as matrix-assisted laser desorption/ionization (MALDI). Since then, various groups have reported measurements of very large proteins by MALDI. Reliable protein analysis by MALDI is more or less well established. However, the application of MALDI to nucleic acids analysis has been found to be much more difficult. Most research on the measurement of nucleic acid by MALDI were stimulated by the Human Genome Project. Up to now, the only method for reliable routine analysis of nucleic acid is gel electrophoresis. Different sizes of nucleic acids can be separated in gel medium when a high electric field is applied to the gel. However, the time needed to separate different sizes of DNA segments usually takes from several minutes to several hours. If MALDI can be successfully used for nucleic acids analysis, the analysis time can be reduced to less than I millisecond. In addition, no tagging with radioactive materials or chemical dyes is needed. In this work, we will review recent progress related to MALDI for DNA analysis.

  12. Direct high-pressure NMR observation of dipicolinic acid leaking from bacterial spore: A crucial step for thermal inactivation.

    Science.gov (United States)

    Akasaka, Kazuyuki; Maeno, Akihiro; Yamazaki, Akira

    2017-12-01

    A bacterial spore protects itself with an unusually high concentration (~10% in dry weight of spore) of dipicolinic acid (DPA), the release of which is considered the crucial step for inactivating it under mild pressure and temperature conditions. However, the process of how the spore releases DPA in response to pressure remains obscure. Here we apply 1 H high-resolution high-pressure NMR spectroscopy, for the first time, to the spore suspension of Bacillus subtilis natto and monitor directly and in real-time the leaking process of DPA in response to pressure of 200MPa at 20°C. We find that about one third of the total DPA leaks immediately upon applying pressure, but that the rest leaks slowly in hrs upon decreasing the pressure. Once DPA is fully released from the spore, the proteins of the spore become easily denatured at a mild temperature, e.g., 80°C, much below the temperature commonly used to inactivate spores (121°C). The success of the present experiment opens a new avenue for studying bacterial spores and cells at the molecular level in response to pressure, temperature and other perturbations. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Study on hydrogen absorption/desorption properties of uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen absorption/desorption properties of two U-Mn intermetallic compounds, U{sub 6}Mn and UMn{sub 2}, were investigated. U{sub 6}Mn absorbed hydrogen and the hydrogen desorption pressure of U{sub 6}Mn obtained from this experiment was higher than that of U, which was considered to be the effect of alloying, whereas UMn{sub 2} was not observed to absorb hydrogen up to 50 atm at room temperature. (author)

  14. Nanoparticle assisted laser desorption/ionization mass spectrometry for small molecule analytes.

    Science.gov (United States)

    Abdelhamid, Hani Nasser

    2018-03-01

    Nanoparticle assisted laser desorption/ionization mass spectrometry (NPs-ALDI-MS) shows remarkable characteristics and has a promising future in terms of real sample analysis. The incorporation of NPs can advance several methods including surface assisted LDI-MS, and surface enhanced LDI-MS. These methods have advanced the detection of many thermally labile and nonvolatile biomolecules. Nanoparticles circumvent the drawbacks of conventional organic matrices for the analysis of small molecules. In most cases, NPs offer a clear background without interfering peaks, absence of fragmentation of thermally labile molecules, and allow the ionization of species with weak noncovalent interactions. Furthermore, an enhancement in sensitivity and selectivity can be achieved. NPs enable straightforward analysis of target species in a complex sample. This review (with 239 refs.) covers the progress made in laser-based mass spectrometry in combination with the use of metallic NPs (such as AuNPs, AgNPs, PtNPs, and PdNPs), NPs consisting of oxides and chalcogenides, silicon-based NPs, carbon-based nanomaterials, quantum dots, and metal-organic frameworks. Graphical abstract An overview is given on nanomaterials for use in surface-assisted laser desorption/ionization mass spectrometry of small molecules.

  15. Direct Dynamics Simulation of the Thermal 3CH2 + 3O2 Reaction. Rate Constant and Product Branching Ratios.

    Science.gov (United States)

    Lakshmanan, Sandhiya; Pratihar, Subha; Machado, Francisco Bolivar Correto; Hase, William Louis

    2018-04-26

    The reaction of 3CH2 with 3O2 is of fundamental importance in combustion and the reaction is complex as a result of multiple extremely exothermic product channels. In the present study, direct dynamics simulations were performed to study the reaction on both the singlet and triplet potential energy surfaces (PESs). The simulations were performed at the UM06/6-311++G(d,p) level of theory. Trajectories were calculated at a temperature of 300 K and all reactive trajectories proceeded through the carbonyl oxide Criegee intermediate, CH2OO, on both the singlet and triplet PESs. The triplet surface leads to only one product channel, H2CO + O(3P), while the singlet surface leads to 8 product channels with their relative importance as: CO + H2O > CO + OH + H ~ H2CO + O(1D) > HCO + OH ~ CO2 + H2 ~ CO + H2 + O(1D) > CO2 + H + H > HCO + O(1D) + H. Reaction on the singlet PES is barrierless, consistent with experiment and the total rate constant on the singlet surface is 0.93 ± 0.22 x 10-12 cm3molecule-1s-1 in comparison to the recommended experimental rate constant of 3.3 x 10-12 cm3molecule-1s-1. The simulation product yields for the singlet PES are compared with experiment and the most significant differences are for H, CO2, and H2O. Reaction on the triplet surface is also barrierless, inconsistent with experiment. A discussion is given of the need for future calculations to address the: (1) barrier on the triplet PES for 3CH2 + 3O2 → 3CH2OO; (2) temperature dependence of the 3CH2 + 3O2 reaction rate constant and product branching ratios; and (3) possible non-RRKM dynamics of the 1CH2OO Criegee intermediate.

  16. Two-phase flow pattern measurements with a wire mesh sensor in a direct steam generating solar thermal collector

    Science.gov (United States)

    Berger, Michael; Mokhtar, Marwan; Zahler, Christian; Willert, Daniel; Neuhäuser, Anton; Schleicher, Eckhard

    2017-06-01

    At Industrial Solar's test facility in Freiburg (Germany), two phase flow patterns have been measured by using a wire mesh sensor from Helmholtz Zentrum Dresden-Rossendorf (HZDR). Main purpose of the measurements was to compare observed two-phase flow patterns with expected flow patterns from models. The two-phase flow pattern is important for the design of direct steam generating solar collectors. Vibrations should be avoided in the peripheral piping, and local dry-outs or large circumferential temperature gradients should be prevented in the absorber tubes. Therefore, the choice of design for operation conditions like mass flow and steam quality are an important step in the engineering process of such a project. Results of a measurement with the wire mesh sensor are the flow pattern and the plug or slug frequency at the given operating conditions. Under the assumption of the collector power, which can be assumed from previous measurements at the same collector and adaption with sun position and incidence angle modifier, also the slip can be evaluated for a wire mesh sensor measurement. Measurements have been performed at different mass flows and pressure levels. Transient behavior has been tested for flashing, change of mass flow, and sudden changes of irradiation (cloud simulation). This paper describes the measurements and the method of evaluation. Results are shown as extruded profiles in top view and in side view. Measurement and model are compared. The tests have been performed at low steam quality, because of the limits of the test facility. Conclusions and implications for possible future measurements at larger collectors are also presented in this paper.

  17. Adsorption and Desorption of Chemical Warfare Agent Simulants on Silica Surfaces with Hydrophobic Coating

    International Nuclear Information System (INIS)

    Park, Eun Ji; Kim, Young Dok

    2013-01-01

    Aim of our study is finding adsorbents suitable for pre-concentration of chemical warfare agents (CWAs). We considered Tenax, bare silica and polydimethylsiloxane (PDMS)-coated silica as adsorbents for dimethyl methylphosphonate (DMMP) and dipropylene glycol methyl ether (DPGME). Tenax showed lower thermal stability, and therefore, desorption of CWA simulants and decomposition of Tenax took place simultaneously. Silica-based adsorbents showed higher thermal stabilities than Tenax. A drawback of silica was that adsorption of CWA simulant (DMMP) was significantly reduced by pre-treatment of the adsorbents with humid air. In the case of PDMS-coated silica, influence of humidity for CWA simulant adsorption was less pronounced due to the hydrophobic nature of PDMS-coating. We propose that PDMS-coated silica can be of potential importance as adsorbent of CWAs for their pre-concentration, which can facilitate detection of these CWAs

  18. Adsorption and Desorption of Chemical Warfare Agent Simulants on Silica Surfaces with Hydrophobic Coating

    Energy Technology Data Exchange (ETDEWEB)

    Park, Eun Ji; Kim, Young Dok [Sungkyunkwan Univ., Suwon (Korea, Republic of)

    2013-07-15

    Aim of our study is finding adsorbents suitable for pre-concentration of chemical warfare agents (CWAs). We considered Tenax, bare silica and polydimethylsiloxane (PDMS)-coated silica as adsorbents for dimethyl methylphosphonate (DMMP) and dipropylene glycol methyl ether (DPGME). Tenax showed lower thermal stability, and therefore, desorption of CWA simulants and decomposition of Tenax took place simultaneously. Silica-based adsorbents showed higher thermal stabilities than Tenax. A drawback of silica was that adsorption of CWA simulant (DMMP) was significantly reduced by pre-treatment of the adsorbents with humid air. In the case of PDMS-coated silica, influence of humidity for CWA simulant adsorption was less pronounced due to the hydrophobic nature of PDMS-coating. We propose that PDMS-coated silica can be of potential importance as adsorbent of CWAs for their pre-concentration, which can facilitate detection of these CWAs.

  19. Laser desorption and time-of-flight mass spectrometry. Fundamentals .Applications

    International Nuclear Information System (INIS)

    Chaurand, P.

    1994-11-01

    Time-of-flight mass spectrometry is a very powerful technique for the analysis of heavy molecular ions (100 000 u and more). The ejection in the gas phase and the ionization of these molecules is now possible through the MALDI technique (Matrix Assisted Laser Desorption Ionization). This technique consists in mixing the heavy molecules to be analysed with a organic matrix which absorbs at the wavelength of the laser. The necessary irradiance are of the order of 10 6 W/cm 2 . In these conditions we have shown that the mass resolutions are optimum and that the relative mass accuracies are of the order of 10 -4 . We have also demonstrated that the emission angle of the molecular ions in MALDI depends on the incident angle of the laser light. During the desorption process, the molecular ions are emitted in the opposite direction of the incident laser light. This effect is particularly important for the design of the accelerating stage of the time-of-flight spectrometers. Problems relative to the detection of these heavy molecular ions have been studied in details between 0.5 10 4 m/s and 10 5 m/s. The velocity threshold of the electronic emission is lower than the value of 0.5 10 4 m/s. The relation between the electronic emission and the projectile velocity is complex. Finally, examples on mass identification of C 60 molecules and derivated C 60 are presented. Desorption methods are compared. (author). 32 refs., 34 figs

  20. Characterization of Rhodamine Self-Assembled Films Using Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Shi, Ruixia; Na, Na; Jiang, Fubin; Ouyang, Jin

    2013-06-01

    Growth process information and molecular structure identification are very important for characterization of self-assembled films. Here, we explore the possible application of desorption electrospray ionization mass spectrometry (DESI-MS) that provides the assembled information of rhodamine B (Rh B) and rhodamine 123 (Rh 123) films. With the help of lab-made DESI source, two characteristic ions [Rh B]+ and [Rh 123]+ are observed directly in the open environment. To evaluate the reliability of this technique, a comparative study of ultraviolet-visible (UV-vis) spectroscopy and our method is carried out, and the result shows good correlation. According to the signal intensity of characteristic ions, the layer-by-layer adsorption process of dyes can be monitored, and the thicknesses of multilayer films can also be comparatively determined. Combining the high sensitivity, selectivity, and speed of mass spectrometry, the selective adsorption of similar structure molecules under different pH is recognized easily from extracted ion chronograms. The variation trend of dyes signalling intensity with concentration of polyelectrolyte is studied as well, which reflects the effect of surface charge on dyes deposition. Additionally, the desorption area, surface morphology, and thicknesses of multilayer films are investigated using fluorescence microscope, scanning electron microscope (SEM), and atomic force microscopy (AFM), respectively. Because the desorption area was approximately as small as 2 mm2, the distribution situation of organic dyes in an arbitrary position could be gained rapidly, which means DESI-MS has advantages on in situ analysis.

  1. Matrix-assisted laser desorption fourier transform mass spectrometry for biological compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hettich, R.; Buchanan, M.

    1990-01-01

    The recent development of matrix-assisted UV laser desorption (LD) mass spectrometry has made possible the ionization and detection of extremely large molecules (with molecular weights exceeding 100,000 Daltons). This technique has generated enormous interest in the biological community for the direct examination of large peptides and oligonucleotides. Although this matrix-assisted ionization method has been developed and used almost exclusively with time-of-flight (TOF) mass spectrometers, research is currently in progress to demonstrate this technique with trapped ion mass spectrometers, such as Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The potential capabilities of FTMS for wide mass range, high resolution measurement, and ion trapping experiments suggest that this instrumental technique should be useful for the detailed structural characterization of large ions generated by the matrix-assisted technique. We have recently demonstrated that matrix-assisted ultraviolet laser desorption can be successfully used with FTMS for the ionization of small peptides. The objective of this report is to summarize the application and current limitations of matrix-assisted laser desorption FTMS for the characterization of peptides and oligonucleotides at the isomeric level. 4 refs., 3 figs., 2 tabs.

  2. Particle desorption mass spectrometric surface characterization

    International Nuclear Information System (INIS)

    Summers, W.R.

    1986-01-01

    The feasibility of utilizing 252 Cf-Particle Desorption Mass Spectro