WorldWideScience

Sample records for thermal compound low-enriched-uranium

  1. 78 FR 75579 - Low Enriched Uranium From France

    Science.gov (United States)

    2013-12-12

    ... COMMISSION Low Enriched Uranium From France Determination On the basis of the record \\1\\ developed in the... antidumping duty order on low enriched uranium from France would be likely to lead to continuation or...), entitled Low Enriched Uranium from France: Investigation No. 731-TA-909 (Second Review). By order of the...

  2. The thermal-mechanical analysis of targets for the high volume production of molybdenum-99 using a low-enriched uranium metal foil

    Science.gov (United States)

    Turner, Kyler Kriens

    Molybdenum-99 diagnostic imaging is the most commonly practiced procedure in nuclear medicine today with the majority molybdenum-99 produced with proliferation sensitive HEU. International and domestic efforts to develop non-HEU production techniques have taking the first steps toward establishing a new non-HEU molybdenum-99 based supply chain. The focus of the research presented in this work is on the analysis of a new high U-235 density LEU based molybdenum-99 production target. Converting directly to LEU using current manufacturing techniques greatly reduces the molybdenum-99 yield per target making high volume production uneconomical. The LEU based foil target analyzed in this research increases the yield per target making economic high volume production with LEU possible. The research analyzed the thermal-mechanical response of an LEU foil target during irradiation. Thermal-mechanical studies focused on deflections and stresses to assess the probability of target failure. Simpler analytical models were used to determine the proper shape of the target and to benchmark the numerical modeling software. Numerical studies using Abaqus focused on analyzing various heating and cooling conditions and assessing the effects of curvature on the target. Finally, experiments were performed to simulate low power heating and further benchmark the models. The results from all of these analyses indicate a LEU foil target could survive irradiation depending on the conditions seen during irradiation.

  3. Conversion of Molybdenum-99 production process to low enriched uranium: Neutronic and thermal hydraulic analyses of HEU and LEU target plates for irradiation in Pakistan Research Reactor-1

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq, Ahmad, E-mail: amushtaq1@hotmail.com [Isotope Production Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Iqbal, Masood; Bokhari, Ishtiaq Hussain; Mahmood, Tayyab; Muhammad, Atta [Nuclear Engineering Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)

    2012-09-15

    Technetium-99m, the daughter product of Molybdenum-99 is the most widely needed radionuclide for diagnostic studies in Pakistan. Molybdenum-99 Production Facility has been established at PINSTECH. Highly enriched uranium (93% {sup 235}U) U/Al alloy targets have been irradiated in Pakistan Research Reactor-1 (PARR-1) for the generation of fission Mo-99, while basic dissolution technique is used for separation of Mo-99 from target matrix activity. In line with the international objective of minimizing and eventually eliminating the use of HEU in civil commerce, national and international efforts have been underway to shift the production of medical isotopes from HEU to LEU (LEU; <20% {sup 235}U enrichment) targets. To achieve the equivalent amount of {sup 99}Mo with LEU targets, approximately 5 times uranium is needed. LEU aluminum uranium dispersion target has been developed, which may replace existing HEU aluminum/uranium alloy targets for production of {sup 99}Mo using basic dissolution technique. Neutronic and thermal hydraulic calculations were performed for safe irradiation of targets in the core of PARR-1.

  4. Enhanced Low-Enriched Uranium Fuel Element for the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pope, M. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); DeHart, M. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Morrell, S. R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jamison, R. K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nef, E. C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nigg, D. W. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    Under the current US Department of Energy (DOE) policy and planning scenario, the Advanced Test Reactor (ATR) and its associated critical facility (ATRC) will be reconfigured to operate on low-enriched uranium (LEU) fuel. This effort has produced a conceptual design for an Enhanced LEU Fuel (ELF) element. This fuel features monolithic U-10Mo fuel foils and aluminum cladding separated by a thin zirconium barrier. As with previous iterations of the ELF design, radial power peaking is managed using different U-10Mo foil thicknesses in different plates of the element. The lead fuel element design, ELF Mk1A, features only three fuel meat thicknesses, a reduction from the previous iterations meant to simplify manufacturing. Evaluation of the ELF Mk1A fuel design against reactor performance requirements is ongoing, as are investigations of the impact of manufacturing uncertainty on safety margins. The element design has been evaluated in what are expected to be the most demanding design basis accident scenarios and has met all initial thermal-hydraulic criteria.

  5. 78 FR 66898 - Low Enriched Uranium From France: Final Results of Changed Circumstances Review

    Science.gov (United States)

    2013-11-07

    ... uranium. Low- enriched uranium is enriched uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of... a U\\235\\ assay of 20 percent or greater, also known as highly- enriched uranium. In addition... rods or assemblies. Natural uranium concentrates (U 3 O 8 ) with a U\\235\\ concentration of no greater...

  6. Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual report for FY 2009

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Sease, John D [ORNL; Guida, Tracey [University of Pittsburgh; Jolly, Brian C [ORNL

    2010-02-01

    This report documents progress made during FY 2009 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Studies are reported of the application of a silicon coating to surrogates for spheres of uranium-molybdenum alloy. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. A description of the progress in developing a finite element thermal hydraulics model of the LEU core is provided.

  7. Preliminary Evaluation of Alternate Designs for HFIR Low-Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Renfro, David G [ORNL; Chandler, David [ORNL; Cook, David Howard [ORNL; Ilas, Germina [ORNL; Jain, Prashant K [ORNL; Valentine, Jennifer R [ORNL

    2014-11-01

    Engineering design studies of the feasibility of conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL) as part of an effort sponsored by the U.S. Department of Energy s Global Threat Reduction Initiative (GTRI)/Reduced Enrichment for Research and Test Reactors (RERTR) program. The fuel type selected by the program for the conversion of the five high-power research reactors in the U.S. that still use HEU fuel is a new U-Mo monolithic fuel. Studies by ORNL have previously indicated that HFIR can be successfully converted using the new fuel provided (1) the reactor power can be increased from 85 MW to 100 MW and (2) the fuel can be fabricated to a specific reference design. Fabrication techniques for the new fuel are under development by the program but are still immature, especially for the complex aspects of the HFIR fuel design. In FY 2012, the program underwent a major shift in focus to emphasize developing and qualifying processes for the fabrication of reliable and affordable LEU fuel. In support of this new focus and in an effort to ensure that the HFIR fuel design is as suitable for reliable fabrication as possible, ORNL undertook the present study to propose and evaluate several alternative design features. These features include (1) eliminating the fuel zone axial contouring in the previous reference design by substituting a permanent neutron absorber in the lower unfueled region of all of the fuel plates, (2) relocating the burnable neutron absorber from the fuel plates of the inner fuel element to the side plates of the inner fuel element (the fuel plates of the outer fuel element do not contain a burnable absorber), (3) relocating the fuel zone inside the fuel plate to be centered on the centerline of the depth of the plate, and (4) reshaping the radial contour of the relocated fuel zone to be symmetric about this centerline. The present

  8. Preliminary Evaluation of Alternate Designs for HFIR Low-Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Renfro, David [ORNL; Chandler, David [ORNL; Cook, David [ORNL; Ilas, Germina [ORNL; Jain, Prashant [ORNL; Valentine, Jennifer [ORNL

    2014-10-30

    Engineering design studies of the feasibility of conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL) as part of an effort sponsored by the U.S. Department of Energy’s Global Threat Reduction Initiative (GTRI)/Reduced Enrichment for Research and Test Reactors (RERTR) program. The fuel type selected by the program for the conversion of the five high-power research reactors in the U.S. that still use HEU fuel is a new U-Mo monolithic fuel. Studies by ORNL have previously indicated that HFIR can be successfully converted using the new fuel provided (1) the reactor power can be increased from 85 MW to 100 MW and (2) the fuel can be fabricated to a specific reference design. Fabrication techniques for the new fuel are under development by the program but are still immature, especially for the “complex” aspects of the HFIR fuel design. In FY 2012, the program underwent a major shift in focus to emphasize developing and qualifying processes for the fabrication of reliable and affordable LEU fuel. In support of this new focus and in an effort to ensure that the HFIR fuel design is as suitable for reliable fabrication as possible, ORNL undertook the present study to propose and evaluate several alternative design features. These features include (1) eliminating the fuel zone axial contouring in the previous reference design by substituting a permanent neutron absorber in the lower unfueled region of all of the fuel plates, (2) relocating the burnable neutron absorber from the fuel plates of the inner fuel element to the side plates of the inner fuel element (the fuel plates of the outer fuel element do not contain a burnable absorber), (3) relocating the fuel zone inside the fuel plate to be centered on the centerline of the depth of the plate, and (4) reshaping the radial contour of the relocated fuel zone to be symmetric about this centerline. The

  9. Low enriched uranium foil plate target for the production of fission Molybdenum-99 in Pakistan Research Reactor-1

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq, A. [Isotope Production Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad, Federal Area 44000 (Pakistan)], E-mail: mushtaqa@pinstech.org.pk; Iqbal, Masood; Bokhari, Ishtiaq Hussain; Mahmood, Tayyab [Nuclear Engineering Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad, Federal Area 44000 (Pakistan)

    2009-04-15

    Low enriched uranium foil (19.99% {sup 235}U) will be used as target material for the production of fission Molybdenum-99 in Pakistan Research Reactor-1 (PARR-1). LEU foil plate target proposed by University of Missouri Research Reactor (MURR) will be irradiated in PARR-1 for the production of 100Ci of Molybdenum-99 at the end of irradiation, which will be sufficient to prepare required {sup 99}Mo/{sup 99m}Tc generators at Pakistan Institute of Nuclear Science and Technology, Islamabad (PINSTECH) and its supply in the country. Neutronic and thermal hydraulic analysis for the fission Molybdenum-99 production at PARR-1 has been performed. Power levels in target foil plates and their corresponding irradiation time durations were initially determined by neutronic analysis to have the required neutron fluence. Finally, the thermal hydraulic analysis has been carried out for the proposed design of the target holder using LEU foil plates for fission Molybdenum-99 production at PARR-1. Data shows that LEU foil plate targets can be safely irradiated in PARR-1 for production of desired amount of fission Molybdenum-99.

  10. Production of Low Enriched Uranium Nitride Kernels for TRISO Particle Irradiation Testing

    Energy Technology Data Exchange (ETDEWEB)

    McMurray, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Silva, C. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Helmreich, G. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gerczak, T. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dyer, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Collins, J. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunt, R. D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lindemer, T. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, K. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-01

    A large batch of UN microspheres to be used as kernels for TRISO particle fuel was produced using carbothermic reduction and nitriding of a sol-gel feedstock bearing tailored amounts of low-enriched uranium (LEU) oxide and carbon. The process parameters, established in a previous study, produced phasepure NaCl structure UN with dissolved C on the N sublattice. The composition, calculated by refinement of the lattice parameter from X-ray diffraction, was determined to be UC0.27N0.73. The final accepted product weighed 197.4 g. The microspheres had an average diameter of 797±1.35 μm and a composite mean theoretical density of 89.9±0.5% for a solid solution of UC and UN with the same atomic ratio; both values are reported with their corresponding calculated standard error.

  11. Low-enriched uranium high-density target project. Compendium report

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, George; Brown, M. Alex; Jerden, James L.; Gelis, Artem V.; Stepinski, Dominique C.; Wiedmeyer, Stanley; Youker, Amanda; Hebden, Andrew; Solbrekken, G; Allen, C; Robertson., D; El-Gizawy, Sherif; Govindarajan, Srisharan; Hoyer, Annemarie; Makarewicz, Philip; Harris, Jacob; Graybill, Brian; Gunn, Andy; Berlin, James; Bryan, Chris; Sherman, Steven; Hobbs, Randy; Griffin, F. P.; Chandler, David; Hurt, C. J.; Williams, Paul; Creasy, John; Tjader, Barak; McFall, Danielle; Longmire, Hollie

    2016-09-01

    At present, most 99Mo is produced in research, test, or isotope production reactors by irradiation of highly enriched uranium targets. To achieve the denser form of uranium needed for switching from high to low enriched uranium (LEU), targets in the form of a metal foil (~125-150 µm thick) are being developed. The LEU High Density Target Project successfully demonstrated several iterations of an LEU-fission-based Mo-99 technology that has the potential to provide the world’s supply of Mo-99, should major producers choose to utilize the technology. Over 50 annular high density targets have been successfully tested, and the assembly and disassembly of targets have been improved and optimized. Two target front-end processes (acidic and electrochemical) have been scaled up and demonstrated to allow for the high-density target technology to mate up to the existing producer technology for target processing. In the event that a new target processing line is started, the chemical processing of the targets is greatly simplified. Extensive modeling and safety analysis has been conducted, and the target has been qualified to be inserted into the High Flux Isotope Reactor, which is considered above and beyond the requirements for the typical use of this target due to high fluence and irradiation duration.

  12. Development of Industrial-Scale Fission 99Mo Production Process Using Low Enriched Uranium Target

    Directory of Open Access Journals (Sweden)

    Seung-Kon Lee

    2016-06-01

    Full Text Available Molybdenum-99 (99Mo is the most important isotope because its daughter isotope, technetium-99m (99mTc, has been the most widely used medical radioisotope for more than 50 years, accounting for > 80% of total nuclear diagnostics worldwide. In this review, radiochemical routes for the production of 99Mo, and the aspects for selecting a suitable process strategy are discussed from the historical viewpoint of 99Mo technology developments. Most of the industrial-scale 99Mo processes have been based on the fission of 235U. Recently, important issues have been raised for the conversion of fission 99Mo targets from highly enriched uranium to low enriched uranium (LEU. The development of new LEU targets with higher density was requested to compensate for the loss of 99Mo yield, caused by a significant reduction of 235U enrichment, from the conversion. As the dramatic increment of intermediate level liquid waste is also expected from the conversion, an effective strategy to reduce the waste generation from the fission 99Mo production is required. The mitigation of radioxenon emission from medical radioisotope production facilities is discussed in relation with the monitoring of nuclear explosions and comprehensive nuclear test ban. Lastly, the 99Mo production process paired with the Korea Atomic Energy Research Institute's own LEU target is proposed as one of the most suitable processes for the LEU target.

  13. Inquiry into disintegration control of irradiated low enrichment uranium for high temperature gas cooled reactors

    Science.gov (United States)

    Reitsamer, G.; Stolba, G.; Falta, G.; Strigl, A.; Zeger, J.; Maly, V.

    1984-07-01

    The PyC-coatings of irradiated high temperature reactor (HTR) fuel particles from AVR fuel elements were burnt off by air and oxygen at 1120K (comparable to the current HTR head-end). Experiments on the solubility of this low enrichment uranium fuel prove that 99.93% of the uranium and 99.84% of the plutonium can be dissolved by 7n HNO3. After additional treatment with 7n HNO3/0.01 n NaF, only 0.01% of the original amount of uranium and 0.01% of the original amount of plutonium remain undissolved. Neither the insoluble residues nor the very small amounts of solids formed on standing (before and after concentrating the solution up to 200 g U/1 and acidity of 3 n HNO3) show any enrichment of plutonium compared with the nitric acid solution. Results indicate that LWR-PUREX-technology can be used for reprocessing HTR-LEU-fuel.

  14. Criticality safety evaluation for the Advanced Test Reactor enhanced low enriched uranium fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Montierth, Leland M. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-07-19

    The Global Threat Reduction Initiative (GTRI) convert program is developing a high uranium density fuel based on a low enriched uranium (LEU) uranium-molybdenum alloy. Testing of prototypic GTRI fuel elements is necessary to demonstrate integrated fuel performance behavior and scale-up of fabrication techniques. GTRI Enhanced LEU Fuel (ELF) elements based on the ATR-Standard Size elements (all plates fueled) are to be fabricated for testing in the Advanced Test Reactor (ATR). While a specific ELF element design will eventually be provided for detailed analyses and in-core testing, this criticality safety evaluation (CSE) is intended to evaluate a hypothetical ELF element design for criticality safety purposes. Existing criticality analyses have analyzed Standard (HEU) ATR elements from which controls have been derived. This CSE documents analysis that determines the reactivity of the hypothetical ELF fuel elements relative to HEU ATR elements and whether the existing HEU ATR element controls bound the ELF element. The initial calculations presented in this CSE analyzed the original ELF design, now referred to as Mod 0.1. In addition, as part of a fuel meat thickness optimization effort for reactor performance, other designs have been evaluated. As of early 2014 the most current conceptual designs are Mk1A and Mk1B, that were previously referred to as conceptual designs Mod 0.10 and Mod 0.11, respectively. Revision 1 evaluates the reactivity of the ATR HEU Mark IV elements for a comparison with the Mark VII elements.

  15. Assembly and Irradiation Modeling of Residual Stresses in Low-Enriched Uranium Foil-Based Annular Targets for Molybdenum-99 Production

    Directory of Open Access Journals (Sweden)

    Srisharan G. Govindarajan

    2013-01-01

    Full Text Available This paper considers a composite cylindrical structure, with low-enriched uranium (LEU foil enclosed between two aluminum 6061-T6 cylinders. A recess is cut all around the outer circumference of the inner tube to accommodate the LEU foil of open-cross section. To obtain perfect contact at the interfaces of the foil and the tubes, an internal pressure is applied to the inner tube, thereby plastically and elastically deforming it. The residual stresses resulting from the assembly process are used along with a thermal stress model to predict the stress margins in the cladding during irradiation. The whole process was simulated as a steady-state two-dimensional problem using the commercial finite element code Abaqus FEA. The irradiation behavior of the annular target has been presented, and the effect of the assembly residual stresses has been discussed.

  16. Fuel Grading Study on a Low-Enriched Uranium Fuel Design for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Germina [ORNL; Primm, Trent [ORNL

    2009-11-01

    An engineering design study that would enable the conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium to low-enriched uranium fuel is ongoing at Oak Ridge National Laboratory. The computational models used to search for a low-enriched uranium (LEU) fuel design that would meet the requirements for the conversion study, and the recent results obtained with these models during FY 2009, are documented and discussed in this report. Estimates of relevant reactor performance parameters for the LEU fuel core are presented and compared with the corresponding data for the currently operating high-enriched uranium fuel core. These studies indicate that the LEU fuel design would maintain the current performance of the HFIR with respect to the neutron flux to the central target region, reflector, and beam tube locations.

  17. CONCEPTUAL PROCESS DESCRIPTION FOR THE MANUFACTURE OF LOW-ENRICHED URANIUM-MOLYBDENUM FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Wachs; Curtis R. Clark; Randall J. Dunavant

    2008-02-01

    The National Nuclear Security Agency Global Threat Reduction Initiative (GTRI) is tasked with minimizing the use of high-enriched uranium (HEU) worldwide. A key component of that effort is the conversion of research reactors from HEU to low-enriched uranium (LEU) fuels. The GTRI Convert Fuel Development program, previously known as the Reduced Enrichment for Research and Test Reactors program was initiated in 1978 by the United States Department of Energy to develop the nuclear fuels necessary to enable these conversions. The program cooperates with the research reactors’ operators to achieve this goal of HEU to LEU conversion without reduction in reactor performance. The programmatic mandate is to complete the conversion of all civilian domestic research reactors by 2014. These reactors include the five domestic high-performance research reactors (HPRR), namely: the High Flux Isotope Reactor at the Oak Ridge National Laboratory, the Advanced Test Reactor at the Idaho National Laboratory, the National Bureau of Standards Reactor at the National Institute of Standards and Technology, the Missouri University Research Reactor at the University of Missouri–Columbia, and the MIT Reactor-II at the Massachusetts Institute of Technology. Characteristics for each of the HPRRs are given in Appendix A. The GTRI Convert Fuel Development program is currently engaged in the development of a novel nuclear fuel that will enable these conversions. The fuel design is based on a monolithic fuel meat (made from a uranium-molybdenum alloy) clad in Al-6061 that has shown excellent performance in irradiation testing. The unique aspects of the fuel design, however, necessitate the development and implementation of new fabrication techniques and, thus, establishment of the infrastructure to ensure adequate fuel fabrication capability. A conceptual fabrication process description and rough estimates of the total facility throughput are described in this document as a basis for

  18. Separation of Fission Molybdenum from Low Enriched Uranium Products by Precipitation with α-Benzoin Oxime

    Directory of Open Access Journals (Sweden)

    WANG Qing-gui;LIANG Ji-xin;WU Yu-xuan;XIANG Xue-qin;LUO Zhi-fu

    2016-11-01

    Full Text Available To separate molybdenum-99 from fission products of low enriched uranium (LEU by precipitation with α-benzoin oxime (α-BO, influences of temperature, concentration of nitrate, molar ratio of α-BO to Mo, radiation dose and uranium concentration on precipitating molybdenum with α-BO had been evaluated. Re-dissolution of MoO2(α-BO2 was performed. The decontamination factors of impurity elements including strontium、 zirconium、 ruthenium、 cesium、 cerium、 iodine-131 and uranium had been determined. The recovery yield of Mo for the separation procedure was calculated. It showed that, at the room temperature, with 1 mol/L of nitric acid concentration , higher than 2 of molar ratio of α-BO to Mo, when α-BO was dissolved in anhydrous ethanol or 0.4 mol/L sodium hydroxide solution, higher than 95% of Mo recovery yield could be obtained. Under the radiation dose rate of 5 000 Gy/h, when the radiation dose increased, Mo recovery yield decreased instead. When the total radiation dose of α-BO was below 8.25×105 Gy, Mo recovery yield was higher than 85%.When uranium concentration increased, Mo recovery yield decreased. MoO2(α-BO2 precipitate could be dissolved in sodium hydroxide of 0.5 mol/L within 15 minutes. Effective decontamination for all major impurity elements including strontium, zirconium, ruthenium, cesium,cerium, iodine and uranium were observed. This study has paved the pay for further research for fission 99Mo production.

  19. A new fast neutron collar for safeguards inspection measurements of fresh low enriched uranium fuel assemblies containing burnable poison rods

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Louise G., E-mail: evanslg@ornl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Swinhoe, Martyn T.; Menlove, Howard O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Schwalbach, Peter; Baere, Paul De [European Commission, Euratom Safeguards Office (Luxembourg); Browne, Michael C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-11-21

    Safeguards inspection measurements must be performed in a timely manner in order to detect the diversion of significant quantities of nuclear material. A shorter measurement time can increase the number of items that a nuclear safeguards inspector can reliably measure during a period of access to a nuclear facility. In turn, this improves the reliability of the acquired statistical sample, which is used to inform decisions regarding compliance. Safeguards inspection measurements should also maintain independence from facility operator declarations. Existing neutron collars employ thermal neutron interrogation for safeguards inspection measurements of fresh fuel assemblies. A new fast neutron collar has been developed for safeguards inspection measurements of fresh low-enriched uranium (LEU) fuel assemblies containing gadolinia (Gd{sub 2}O{sub 3}) burnable poison rods. The Euratom Fast Collar (EFC) was designed with high neutron detection efficiency to make a fast (Cd) mode measurement viable whilst meeting the high counting precision and short assay time requirements of the Euratom safeguards inspectorate. A fast mode measurement reduces the instrument sensitivity to burnable poison rod content and therefore reduces the applied poison correction, consequently reducing the dependence on the operator declaration of the poison content within an assembly. The EFC non-destructive assay (NDA) of typical modern European pressurized water reactor (PWR) fresh fuel assembly designs have been simulated using Monte Carlo N-particle extended transport code (MCNPX) simulations. Simulations predict that the EFC can achieve 2% relative statistical uncertainty on the doubles neutron counting rate for a fast mode measurement in an assay time of 600 s (10 min) with the available {sup 241}AmLi (α,n) interrogation source strength of 5.7×10{sup 4} s{sup −1}. Furthermore, the calibration range of the new collar has been extended to verify {sup 235}U content in variable PWR fuel

  20. A new fast neutron collar for safeguards inspection measurements of fresh low enriched uranium fuel assemblies containing burnable poison rods

    Science.gov (United States)

    Evans, Louise G.; Swinhoe, Martyn T.; Menlove, Howard O.; Schwalbach, Peter; Baere, Paul De; Browne, Michael C.

    2013-11-01

    Safeguards inspection measurements must be performed in a timely manner in order to detect the diversion of significant quantities of nuclear material. A shorter measurement time can increase the number of items that a nuclear safeguards inspector can reliably measure during a period of access to a nuclear facility. In turn, this improves the reliability of the acquired statistical sample, which is used to inform decisions regarding compliance. Safeguards inspection measurements should also maintain independence from facility operator declarations. Existing neutron collars employ thermal neutron interrogation for safeguards inspection measurements of fresh fuel assemblies. A new fast neutron collar has been developed for safeguards inspection measurements of fresh low-enriched uranium (LEU) fuel assemblies containing gadolinia (Gd2O3) burnable poison rods. The Euratom Fast Collar (EFC) was designed with high neutron detection efficiency to make a fast (Cd) mode measurement viable whilst meeting the high counting precision and short assay time requirements of the Euratom safeguards inspectorate. A fast mode measurement reduces the instrument sensitivity to burnable poison rod content and therefore reduces the applied poison correction, consequently reducing the dependence on the operator declaration of the poison content within an assembly. The EFC non-destructive assay (NDA) of typical modern European pressurized water reactor (PWR) fresh fuel assembly designs have been simulated using Monte Carlo N-particle extended transport code (MCNPX) simulations. Simulations predict that the EFC can achieve 2% relative statistical uncertainty on the doubles neutron counting rate for a fast mode measurement in an assay time of 600 s (10 min) with the available 241AmLi (α,n) interrogation source strength of 5.7×104 s-1. Furthermore, the calibration range of the new collar has been extended to verify 235U content in variable PWR fuel designs in the presence of up to 32

  1. Low enriched uranium UAl{sub X}-Al targets for the production of Molybdenum-99 in the IEA-R1 and RMB reactors

    Energy Technology Data Exchange (ETDEWEB)

    Domingos, Douglas B.; Silva, Antonio T. e; Joao, Thiago G.; Silva, Jose Eduardo R. da, E-mail: teixeira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Nishiyama, Pedro J.B. de O., E-mail: pedro.julio@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil)

    2011-07-01

    The IEA-R1 reactor of IPEN/CNEN-SP in Brazil is a pool type research reactor cooled and moderated by demineralized water and having Beryllium and Graphite as reflectors. In 1997 the reactor received the operating licensing for 5 MW. A new research reactor is being planned in Brazil to replace the IEA-R1 reactor. This new reactor, the Brazilian Multipurpose Reactor (RMB), planned for 30 MW, is now in the conception design phase. Low enriched uranium (LEU) (<20% {sup 235}U) UAl{sub x} dispersed in Al targets are being considered for production of Molybdenum-99 ({sup 99}Mo) by fission. Neutronic and thermal-hydraulics calculations were performed, respectively, to compare the production of {sup 99}Mo for these targets in IEA-R1 reactor and RMB and to determine the temperatures achieved in the UAl{sub x}-Al targets during irradiation. For the neutronic calculations were utilized the computer codes HAMMER-TECHNION, CITATION and SCALE and for the thermal-hydraulics calculations was utilized the computer code MTRCR-IEAR1. (author)

  2. Low-Enriched Uranium Fuel Design with Two-Dimensional Grading for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Germina [ORNL; Primm, Trent [ORNL

    2011-05-01

    An engineering design study of the conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel is ongoing at Oak Ridge National Laboratory. The computational models developed during fiscal year 2010 to search for an LEU fuel design that would meet the requirements for the conversion and the results obtained with these models are documented and discussed in this report. Estimates of relevant reactor performance parameters for the LEU fuel core are presented and compared with the corresponding data for the currently operating HEU fuel core. The results obtained indicate that the LEU fuel design would maintain the current performance of the HFIR with respect to the neutron flux to the central target region, reflector, and beam tube locations under the assumption that the operating power for the reactor fueled with LEU can be increased from the current value of 85 MW to 100 MW.

  3. Environmental assessment: Transfer of normal and low-enriched uranium billets to the United Kingdom, Hanford Site, Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    Under the auspices of an agreement between the U.S. and the United Kingdom, the U.S. Department of Energy (DOE) has an opportunity to transfer approximately 710,000 kilograms (1,562,000 pounds) of unneeded normal and low-enriched uranium (LEU) to the United Kingdom; thus, reducing long-term surveillance and maintenance burdens at the Hanford Site. The material, in the form of billets, is controlled by DOE`s Defense Programs, and is presently stored as surplus material in the 300 Area of the Hanford Site. The United Kingdom has expressed a need for the billets. The surplus uranium billets are currently stored in wooden shipping containers in secured facilities in the 300 Area at the Hanford Site (the 303-B and 303-G storage facilities). There are 482 billets at an enrichment level (based on uranium-235 content) of 0.71 weight-percent. This enrichment level is normal uranium; that is, uranium having 0.711 as the percentage by weight of uranium-235 as occurring in nature. There are 3,242 billets at an enrichment level of 0.95 weight-percent (i.e., low-enriched uranium). This inventory represents a total of approximately 532 curies. The facilities are routinely monitored. The dose rate on contact of a uranium billet is approximately 8 millirem per hour. The dose rate on contact of a wooden shipping container containing 4 billets is approximately 4 millirem per hour. The dose rate at the exterior of the storage facilities is indistinguishable from background levels.

  4. Validation of SCALE 4.0 -- CSAS25 module and the 27-group ENDF/B-IV cross-section library for low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, W.C.

    1993-02-01

    A version of KENO V.a and the 27-group library in SCALE-4.0 were validated for use in evaluating the nuclear criticality safety of low-enriched uranium systems. A total of 59 critical systems were analyzed. A statistical analysis of the results was performed, and subcritical acceptanced criteria are established.

  5. Validation of SCALE 4. 0 -- CSAS25 module and the 27-group ENDF/B-IV cross-section library for low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, W.C.

    1993-02-01

    A version of KENO V.a and the 27-group library in SCALE-4.0 were validated for use in evaluating the nuclear criticality safety of low-enriched uranium systems. A total of 59 critical systems were analyzed. A statistical analysis of the results was performed, and subcritical acceptanced criteria are established.

  6. Comparison of low enriched uranium (UAl{sub x}-Al and U-Ni) targets with different geometries for the production of molybdenum-99 in the RMB (Brazilian multipurpose reactor)

    Energy Technology Data Exchange (ETDEWEB)

    Domingos, Douglas B.; Silva, Antonio T. e; Joao, Thiago G.; Silva, Jose Eduardo R. da; Angelo, Gabriel; Fedorenko, Giuliana G., E-mail: teixeira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Nishiyama, Pedro J.B. de O., E-mail: pedro.julio@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)

    2011-07-01

    The Brazilian Multipurpose Reactor (RMB), now in the conception design phase, is being designed in Brazil to attend the demand of radiopharmaceuticals in the country and conduct researches in various areas. The new reactor, planned for 30 MW, will replace the IEA-R1 reactor of IPEN-CNEN/SP. Low enriched uranium (<20% {sup 235}U) UAl{sub x} dispersed in Al (plate geometry) and metallic uranium foil targets (plate and cylinder geometries) are being considered for production of Molybdenum-99 ({sup 99}Mo) by fission. Neutronic and thermal-hydraulics calculations were performed to compare the production of {sup 99}Mo for these targets in the RMB. For the neutronic calculations were utilized the computer codes Hammer-Technion, Citation and Scale and for the thermal-hydraulics calculations were utilized the computer code MTRCR-IEAR1 and ANSYS CFX. (author)

  7. A cellular automaton method to simulate the microstructure and evolution of low-enriched uranium (LEU) U–Mo/Al dispersion type fuel plates

    Energy Technology Data Exchange (ETDEWEB)

    Drera, Saleem S., E-mail: saleem.drera@gmail.com [Mechanical Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Hofman, Gerard L. [Argonne National Laboratory, Chicago, IL 60439 (United States); Kee, Robert J. [Mechanical Engineering, Colorado School of Mines, Golden, CO 80401 (United States); King, Jeffrey C. [Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO 80401 (United States)

    2014-10-15

    Highlights: • This article presents a cellular automata (CA) algorithm to synthesize the growth of intermetallic interaction layers in U–Mo/Al dispersion fuel. • The method utilizes a 3D representation of the fuel, which is discretized into separate voxels that can change identy based on derived CA rules. • The CA model is compared to ILT measurements for RERTR experimental data. • The primary objective of the model is to synthesize three-dimensional microstructures that can be used in subsequent thermal and mechanical modeling. • The CA model can be used for predictive analysis. For example, it can be used to study the dependence of temperature on interaction layer growth. - Abstract: Low-enriched uranium (LEU) fuel plates for high power materials test reactors (MTR) are composed of nominally spherical uranium–molybdenum (U–Mo) particles within an aluminum matrix. Fresh U–Mo particles typically range between 10 and 100 μm in diameter, with particle volume fractions up to 50%. As the fuel ages, reaction–diffusion processes cause the formation and growth of interaction layers that surround the fuel particles. The growth rate depends upon the temperature and radiation environment. The cellular automaton algorithm described in this paper can synthesize realistic random fuel-particle structures and simulate the growth of the intermetallic interaction layers. Examples in the present paper pack approximately 1000 particles into three-dimensional rectangular fuel structures that are approximately 1 mm on each side. The computational approach is designed to yield synthetic microstructures consistent with images from actual fuel plates and is validated by comparison with empirical data on actual fuel plates.

  8. DIissolution of low enriched uranium from the experimental breeder reactor-II fuel stored at the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Almond, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); O' Rourke, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-28

    The Idaho National Laboratory (INL) is actively engaged in the development of electrochemical processing technology for the treatment of fast reactor fuels using irradiated fuel from the Experimental Breeder Reactor-II (EBR-II) as the primary test material. The research and development (R&D) activities generate a low enriched uranium (LEU) metal product from the electrorefining of the EBR-II fuel and the subsequent consolidation and removal of chloride salts by the cathode processor. The LEU metal ingots from past R&D activities are currently stored at INL awaiting disposition. One potential disposition pathway is the shipment of the ingots to the Savannah River Site (SRS) for dissolution in H-Canyon. Carbon steel cans containing the LEU metal would be loaded into reusable charging bundles in the H-Canyon Crane Maintenance Area and charged to the 6.4D or 6.1D dissolver. The LEU dissolution would be accomplished as the final charge in a dissolver batch (following the dissolution of multiple charges of spent nuclear fuel (SNF)). The solution would then be purified and the 235U enrichment downblended to allow use of the U in commercial reactor fuel. To support this potential disposition path, the Savannah River National Laboratory (SRNL) developed a dissolution flowsheet for the LEU using samples of the material received from INL.

  9. Radionuclide inventories : ORIGEN2.2 isotopic depletion calculation for high burnup low-enriched uranium and weapons-grade mixed-oxide pressurized-water reactor fuel assemblies.

    Energy Technology Data Exchange (ETDEWEB)

    Gauntt, Randall O.; Ross, Kyle W. (Los Alamos National Laboratory, Los Alamos, NM); Smith, James Dean; Longmire, Pamela

    2010-04-01

    The Oak Ridge National Laboratory computer code, ORIGEN2.2 (CCC-371, 2002), was used to obtain the elemental composition of irradiated low-enriched uranium (LEU)/mixed-oxide (MOX) pressurized-water reactor fuel assemblies. Described in this report are the input parameters for the ORIGEN2.2 calculations. The rationale for performing the ORIGEN2.2 calculation was to generate inventories to be used to populate MELCOR radionuclide classes. Therefore the ORIGEN2.2 output was subsequently manipulated. The procedures performed in this data reduction process are also described herein. A listing of the ORIGEN2.2 input deck for two-cycle MOX is provided in the appendix. The final output from this data reduction process was three tables containing the radionuclide inventories for LEU/MOX in elemental form. Masses, thermal powers, and activities were reported for each category.

  10. Proposal of new 235U nuclear data to improve keff biases on 235U enrichment and temperature for low enriched uranium fueled lattices moderated by light water

    OpenAIRE

    Wu, H; 奥村 啓介; 柴田 恵一

    2005-01-01

    The under prediction of keff depending on 235U enrichment in low enriched uranium fueled systems was studied in this report. Benchmark testing was carried out with several evaluated nuclear data files, including the new uranium evaluations from preliminary ENDF/B-VII and CENDL-3.1. Another problem reviewed here was keff underestimation vs. temperature increase, which was observed in the slightly enriched system with recent JENDL and ENDF/B uranium evaluations. Through the substitute analysis ...

  11. Preliminary Assessment of the Impact on Reactor Vessel dpa Rates Due to Installation of a Proposed Low Enriched Uranium (LEU) Core in the High Flux Isotope Reactor (HFIR)

    Energy Technology Data Exchange (ETDEWEB)

    Daily, Charles R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-01

    An assessment of the impact on the High Flux Isotope Reactor (HFIR) reactor vessel (RV) displacements-per-atom (dpa) rates due to operations with the proposed low enriched uranium (LEU) core described by Ilas and Primm has been performed and is presented herein. The analyses documented herein support the conclusion that conversion of HFIR to low-enriched uranium (LEU) core operations using the LEU core design of Ilas and Primm will have no negative impact on HFIR RV dpa rates. Since its inception, HFIR has been operated with highly enriched uranium (HEU) cores. As part of an effort sponsored by the National Nuclear Security Administration (NNSA), conversion to LEU cores is being considered for future HFIR operations. The HFIR LEU configurations analyzed are consistent with the LEU core models used by Ilas and Primm and the HEU balance-of-plant models used by Risner and Blakeman in the latest analyses performed to support the HFIR materials surveillance program. The Risner and Blakeman analyses, as well as the studies documented herein, are the first to apply the hybrid transport methods available in the Automated Variance reduction Generator (ADVANTG) code to HFIR RV dpa rate calculations. These calculations have been performed on the Oak Ridge National Laboratory (ORNL) Institutional Cluster (OIC) with version 1.60 of the Monte Carlo N-Particle 5 (MCNP5) computer code.

  12. Safety evaluation report related to the evaluation of low-enriched uranium silicide-aluminum dispersion fuel for use in non-power reactors

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    Low-enriched uranium silicide-aluminum dispersion plate-type fuels have been extensively researched and developed under the international program, Reduced Enrichment in Research and Test Reactors. The international effort was led by Argonne National Laboratory (ANL) in the United States. This evaluation is based primarily on reports issued by ANL that discuss and summarize the developmental tests and experiments, including postirradiation examinations, of both miniature and full-sized plates of prototypical fuel compositions. This evaluation concludes that plate-type fuels suitable and acceptable for use in research and test reactors can be fabricated with U/sub 3/Si/sub 2/-Al dispersion compacts with uranium densities up to 4.8 g/cm/sup 3/. 4 refs., 1 fig.

  13. Accident Analyses for Conversion of the University of Missouri Research Reactor (MURR) from Highly-Enriched to Low-Enriched Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Stillman, J. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Feldman, E. E. [Argonne National Lab. (ANL), Argonne, IL (United States); Jaluvka, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Wilson, E. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Foyto, L. P. [Univ. of Missouri, Columbia, MO (United States); Kutikkad, K. [Univ. of Missouri, Columbia, MO (United States); McKibben, J. C. [Univ. of Missouri, Columbia, MO (United States); Peters, N. J. [Univ. of Missouri, Columbia, MO (United States)

    2017-02-01

    This report contains the results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members in the Research and Test Reactor Department at the Argonne National Laboratory (ANL) and the MURR Facility. MURR LEU conversion is part of an overall effort to develop and qualify high-density fuel within the U.S. High Performance Research Reactor Conversion (USHPRR) program conducted by the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization (M3).

  14. A study of a zone approach to IAEA (International Atomic Energy Agency) safeguards: The low-enriched-uranium zone of a light-water-reactor fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Fishbone, L.G.; Higinbotham, W.A.

    1986-06-01

    At present the IAEA designs its safeguards approach with regard to each type of nuclear facility so that the safeguards activities and effort are essentially the same for a given type and size of nuclear facility wherever it may be located. Conclusions regarding a state are derived by combining the conclusions regarding the effectiveness of safeguards for the individual facilities within a state. In this study it was convenient to define three zones in a state with a closed light-water-reactor nuclear fuel cycle. Each zone contains those facilities or parts thereof which use or process nuclear materials of the same safeguards significance: low-enriched uranium, radioactive spent fuel, or recovered plutonium. The possibility that each zone might be treated as an extended material balance area for safeguards purposes is under investigation. The approach includes defining the relevant features of the facilities in the three zones and listing the safeguards activities which are now practiced. This study has focussed on the fresh-fuel zone, the several facilities of which use or process low-enriched uranium. At one extreme, flows and inventories would be verified at each material balance area. At the other extreme, the flows into and out of the zone and the inventory of the whole zone would be verified. There are a number of possible safeguards approaches which fall between the two extremes. The intention is to develop a rational approach which will make it possible to compare the technical effectiveness and the inspection effort for the facility-oriented approach, for the approach involving the zone as a material balance area, and for some reasonable intermediate safeguards approaches.

  15. Accident Analyses for Conversion of the University of Missouri Research Reactor (MURR) from Highly-Enriched to Low-Enriched Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Stillman, J. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Div., Research and Test Reactor Dept.; Feldman, E. E. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Div., Research and Test Reactor Dept.; Wilson, E. H. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Div., Research and Test Reactor Dept.; Foyto, L. P. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; Kutikkad, K. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; McKibben, J. C. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; Peters, N. J. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; Cowherd, W. M. [Univ. of Missouri, Columbia, MO (United States). College of Engineering, Nuclear Engineering Program; Rickman, B. [Univ. of Missouri, Columbia, MO (United States). College of Engineering, Nuclear Engineering Program

    2014-12-01

    This report contains the results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL), the MURR Facility, and the Nuclear Engineering Program – College of Engineering, University of Missouri-Columbia. The core conversion to LEU is being performed with financial support from the U. S. government. This report contains the results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL), the MURR Facility, and the Nuclear Engineering Program – College of Engineering, University of Missouri-Columbia. The core conversion to LEU is being performed with financial support from the U. S. government. In the framework of non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context most research and test reactors, both domestic and international, have started a program of conversion to the use of LEU fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (U-Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MURR. This report presents the results of a study of core behavior under a set of accident conditions for MURR cores fueled with HEU U-Alx dispersion fuel or LEU monolithic U-Mo alloy fuel with 10 wt% Mo

  16. Low enriched uranium foil targets with different geometries for the production of Molybdenum-99 in the BMR (Brazilian Multipurpose Reactor)

    Energy Technology Data Exchange (ETDEWEB)

    Domingos, Douglas B.; Silva, Antonio T. e; Joao, Thiago G.; Muniz, Rafael O.R.; Coelho, Talita S., E-mail: teixeira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    A new research reactor is being planned in Brazil to take care of the demand of radiopharmaceuticals in the country and conduct research in various areas. This new reactor, the Brazilian Multipurpose Reactor (RMB), planned for 30 MW, is now in the conception design phase. Two low enriched (<20% {sup 235}U) metallic uranium foil targets (cylinder and plate geometries) are being considered for production of Molybdenum-99 ({sup 99}Mo) by fission. Neutronic and thermal-hydraulics calculations were performed to compare the production of {sup 99}Mo for these targets in the RMB and to determine the temperatures achieved in the targets. For the neutronic calculations were utilized the computer codes HAMMER-TECHNION, CITATION and SCALE and for the thermal-hydraulics calculations were utilized the computer codes MTRCR-IEA-R1 and ANSYS CFX. (author)

  17. Nuclear safety analyses and core design calculations to convert the Texas A & M University Nuclear Science Center reactor to low enrichment uranium fuel. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Parish, T.A.

    1995-03-02

    This project involved performing the nuclear design and safety analyses needed to modify the license issued by the Nuclear Regulatory Commission to allow operation of the Texas A& M University Nuclear Science Center Reactor (NSCR) with a core containing low enrichment uranium (LEU) fuel. The specific type of LEU fuel to be considered was the TRIGA 20-20 fuel produced by General Atomic. Computer codes for the neutronic analyses were provided by Argonne National Laboratory (ANL) and the assistance of William Woodruff of ANL in helping the NSCR staff to learn the proper use of the codes is gratefully acknowledged. The codes applied in the LEU analyses were WIMSd4/m, DIF3D, NCTRIGA and PARET. These codes allowed full three dimensional, temperature and burnup dependent calculations modelling the NSCR core to be performed for the first time. In addition, temperature coefficients of reactivity and pulsing calculations were carried out in-house, whereas in the past this modelling had been performed at General Atomic. In order to benchmark the newly acquired codes, modelling of the current NSCR core with highly enriched uranium fuel was also carried out. Calculated results were compared to both earlier licensing calculations and experimental data and the new methods were found to achieve excellent agreement with both. Therefore, even if an LEU core is never loaded at the NSCR, this project has resulted in a significant improvement in the nuclear safety analysis capabilities established and maintained at the NSCR.

  18. Environmental assessment for the purchase of Russian low enriched uranium derived from the dismantlement of nuclear weapons in the countries of the former Soviet Union

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-01

    The United States is proposing to purchase from the Russian Federation low enriched uranium (LEU) derived from highly enriched uranium (HEU) resulting from the dismantlement of nuclear weapons in the countries of the former Soviet Union. The purchase would be accomplished through a proposed contract requiring the United States to purchase 15,250 metric tons (tonnes) of LEU (or 22,550 tonnes of UF{sub 6}) derived from blending 500 metric tones uranium (MTU) of HEU from nuclear warheads. The LEU would be in the form of uranium hexafluoride (UF{sub 6}) and would be converted from HEU in Russia. The United States Enrichment Corporation (USEC) is the entity proposing to undertake the contract for purchase, sale, and delivery of the LEU from the Russian Federation. The US Department of Energy (DOE) is negotiating the procedure for gaining confidence that the LEU is derived from HEU that is derived from dismantled nuclear weapons (referred to as ``transparency),`` and would administer the transparency measures for the contract. There are six environments that could potentially be affected by the proposed action; marine (ocean); US ports of entry; truck or rail transportation corridors; the Portsmouth GDP; the electric power industry; and the nuclear fuel cycle industry. These environmental impacts are discussed.

  19. Preliminary Accident Analyses for Conversion of the Massachusetts Institute of Technology Reactor (MITR) from Highly Enriched to Low Enriched Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Floyd E. [Argonne National Lab. (ANL), Argonne, IL (United States); Olson, Arne P. [Argonne National Lab. (ANL), Argonne, IL (United States); Wilson, Erik H. [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Kaichao S. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Newton, Jr., Thomas H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Hu, Lin-wen [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2013-09-30

    The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. It delivers a neutron flux comparable to current LWR power reactors in a compact 6 MW core using Highly Enriched Uranium (HEU) fuel. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context most research and test reactors, both domestic and international, have started a program of conversion to the use of LEU fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (U-Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MITR. This report presents the preliminary accident analyses for MITR cores fueled with LEU monolithic U-Mo alloy fuel with 10 wt% Mo. Preliminary results demonstrate adequate performance, including thermal margin to expected safety limits, for the LEU accident scenarios analyzed.

  20. In-Situ Measurements of Low Enrichment Uranium Holdup Process Gas Piping at K-25 - Paper for Waste Management Symposia 2010 East Tennessee Technology Park Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen B.

    2010-01-01

    This document is the final version of a paper submitted to the Waste Management Symposia, Phoenix, 2010, abstract BJC/OR-3280. The primary document from which this paper was condensed is In-Situ Measurement of Low Enrichment Uranium Holdup in Process Gas Piping at K-25 Using NaI/HMS4 Gamma Detection Systems, BJC/OR-3355. This work explores the sufficiency and limitations of the Holdup Measurement System 4 (HJVIS4) software algorithms applied to measurements of low enriched uranium holdup in gaseous diffusion process gas piping. HMS4 has been used extensively during the decommissioning and demolition project of the K-25 building for U-235 holdup quantification. The HMS4 software is an integral part of one of the primary nondestructive assay (NDA) systems which was successfully tested and qualified for holdup deposit quantification in the process gas piping of the K-25 building. The initial qualification focused on the measurement of highly enriched UO{sub 2}F{sub 2} deposits. The purpose of this work was to determine if that qualification could be extended to include the quantification of holdup in UO{sub 2}F{sub 2} deposits of lower enrichment. Sample field data are presented to provide evidence in support of the theoretical foundation. The HMS4 algorithms were investigated in detail and found to sufficiently compensate for UO{sub 2}F{sub 2} source self-attenuation effects, over the range of expected enrichment (4-40%), in the North and East Wings of the K-25 building. The limitations of the HMS4 algorithms were explored for a described set of conditions with respect to area source measurements of low enriched UO{sub 2}F{sub 2} deposits when used in conjunction with a 1 inch by 1/2 inch sodium iodide (NaI) scintillation detector. The theoretical limitations of HMS4, based on the expected conditions in the process gas system of the K-25 building, are related back to the required data quality objectives (DQO) for the NBA measurement system established for the K-25

  1. Research and Development of Multiphysics Models in Support of the Conversion of the High Flux Isotope Reactor to Low Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Bodey, Isaac T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Curtis, Franklin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Arimilli, Rao V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ekici, Kivanc [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Freels, James D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-11-01

    The findings presented in this report are results of a five year effort led by the RRD Division of the ORNL, which is focused on research and development toward the conversion of the High Flux Isotope Reactor (HFIR) fuel from high-enriched uranium (HEU) to low-enriched uranium (LEU). This report focuses on the tasks accomplished by the University of Tennessee Knoxville (UTK) team from the Department of Mechanical, Aerospace, and Biomedical Engineering (MABE) that provided expert support in multiphysics modeling of complex problems associated with the LEU conversion of the HFIR reactor. The COMSOL software was used as the main computational modeling tool, whereas Solidworks was also used in support of computer-aided-design (CAD) modeling of the proposed LEU fuel design. The UTK research has been governed by a statement of work (SOW), which was updated annually to clearly define the specific tasks reported herein. Ph.D. student Isaac T. Bodey has focused on heat transfer and fluid flow modeling issues and has been aided by his major professor Dr. Rao V. Arimilli. Ph.D. student Franklin G. Curtis has been focusing on modeling the fluid-structure interaction (FSI) phenomena caused by the mechanical forces acting on the fuel plates, which in turn affect the fluid flow in between the fuel plates, and ultimately the heat transfer, is also affected by the FSI changes. Franklin Curtis has been aided by his major professor Dr. Kivanc Ekici. M.Sc. student Adam R. Travis has focused two major areas of research: (1) on accurate CAD modeling of the proposed LEU plate design, and (2) reduction of the model complexity and dimensionality through interdimensional coupling of the fluid flow and heat transfer for the HFIR plate geometry. Adam Travis is also aided by his major professor, Dr. Kivanc Ekici. We must note that the UTK team, and particularly the graduate students, have been in very close collaboration with Dr. James D. Freels (ORNL technical monitor and mentor) and have

  2. Reactor Physics Methods and Preconceptual Core Design Analyses for Conversion of the Advanced Test Reactor to Low-Enriched Uranium Fuel Annual Report for Fiscal Year 2012

    Energy Technology Data Exchange (ETDEWEB)

    David W. Nigg; Sean R. Morrell

    2012-09-01

    Under the current long-term DOE policy and planning scenario, both the ATR and the ATRC will be reconfigured at an appropriate time within the next several years to operate with low-enriched uranium (LEU) fuel. This will be accomplished under the auspices of the Reduced Enrichment Research and Test Reactor (RERTR) Program, administered by the DOE National Nuclear Security Administration (NNSA). At a minimum, the internal design and composition of the fuel element plates and support structure will change, to accommodate the need for low enrichment in a manner that maintains total core excess reactivity at a suitable level for anticipated operational needs throughout each cycle while respecting all control and shutdown margin requirements and power distribution limits. The complete engineering design and optimization of LEU cores for the ATR and the ATRC will require significant multi-year efforts in the areas of fuel design, development and testing, as well as a complete re-analysis of the relevant reactor physics parameters for a core composed of LEU fuel, with possible control system modifications. Ultimately, revalidation of the computational physics parameters per applicable national and international standards against data from experimental measurements for prototypes of the new ATR and ATRC core designs will also be required for Safety Analysis Report (SAR) changes to support routine operations with LEU. This report is focused on reactor physics analyses conducted during Fiscal Year (FY) 2012 to support the initial development of several potential preconceptual fuel element designs that are suitable candidates for further study and refinement during FY-2013 and beyond. In a separate, but related, effort in the general area of computational support for ATR operations, the Idaho National Laboratory (INL) is conducting a focused multiyear effort to introduce modern high-fidelity computational reactor physics software and associated validation protocols to replace

  3. Investigative studies on the effects of cadmium rabbits on high enriched uranium-fueled and low enriched uranium-fueled cores of Ghana Research Reactor-1 using MCNP5 code

    Energy Technology Data Exchange (ETDEWEB)

    Boffie, J., E-mail: jboffie@yahoo.com [Department of Nuclear Engineering and Material Science, School of Nuclear and Allied Sciences (SNAS), University of Ghana, P.O. Box AE 1, Atomic Energy, Accra (Ghana); National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Akaho, E.H.K. [Department of Nuclear Engineering and Material Science, School of Nuclear and Allied Sciences (SNAS), University of Ghana, P.O. Box AE 1, Atomic Energy, Accra (Ghana); Nyarko, B.J.B.; Odoi, H.C.; Tuffour-Achampong, K.; Abrefah, R.G. [Department of Nuclear Engineering and Material Science, School of Nuclear and Allied Sciences (SNAS), University of Ghana, P.O. Box AE 1, Atomic Energy, Accra (Ghana); National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana)

    2013-12-15

    Highlights: • The operating parameters for both the HEU core and proposed LEU core were similar. • The length of the Cd in the capsules must be increased for its use in the LEU core. • Cd rabbits can emergently be used to shut down MNSRs. - Abstract: Miniature Neutron Source Reactors (MNSRs) are noted to be among highly safe research reactors. However, because of its use of one control rod for reactivity control and shutdown purposes, alternative methods of shutting it down are important. The Ghana MNSR uses four cadmium rabbits of approximate dimensions 6.5 cm × 5.0 cm × 0.1 cm and mass of 9.48 g each to emergently shut down the reactor. The Monte Carlo N-Particle code; version 5, (MCNP5) was used to design the high enriched uranium (HEU) and low enriched uranium (LEU) cores of the MNSR with four cadmium rabbits inserted in four inner irradiation sites of each core. The operating parameters and shutdown parameters for both cores with the central control rod (CCR) either fully withdrawn or fully inserted had similar results with the HEU core having slightly better results in terms of safety. However, the results show that the four inserted cadmium rabbits make the HEU core subcritical whiles in the LEU core, it still remains critical (k{sub eff} = 1.00005 ± 0.00007). The length of the cadmium material in each cadmium rabbit must therefore be increased by at least 0.5 cm in order to attain subcriticality (k{sub eff} = 0.99989 ± 0.00006) and shutdown margin of 0.11 mk when inserted in the LEU core.

  4. Negative thermal expansion in framework compounds

    Indian Academy of Sciences (India)

    electron microscopy, EXAFS and differential scanning calorimetry have been used to study structural properties as a function of temperature for these compounds. In this paper we report the results obtained from our study [14–20] of negative thermal expansion (NTE) compounds with chemical compositions of NX2O8 and.

  5. Biodegradable compounds: Rheological, mechanical and thermal properties

    Science.gov (United States)

    Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

    2015-12-01

    Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

  6. Negative thermal expansion in framework compounds

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... We have studied negative thermal expansion (NTE) compounds with chemi- cal compositions of NX2O8 and NX2O7 (N=Zr, Hf and X=W, Mo, V) and M2O (M=Cu, Ag) using the techniques of inelastic neutron scattering and lattice dynamics. There is a large variation in the negative thermal expansion ...

  7. Compound Refractive Lenses for Thermal Neutron Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gary, Charles K.

    2013-11-12

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 μm which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  8. DEVELOPMENT OF HIGH THERMAL CONDUCTIVITY ELECTRICAL EMBEDDING COMPOUNDS.

    Science.gov (United States)

    This report describes the development of high thermal conductivity electrical embedding compounds utilizing a technique wherein the mold is first...Contained herein, are the pertinent results of a previously reported study which led to the development of three high thermal conductivity compounds...and the further development of several additional compounds with still higher conductivities. (Author)

  9. Neutronic and thermal hydraulic analysis for production of fission molybdenum-99 at Pakistan Research Reactor-1

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq, A. [Isotope Production Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)], E-mail: mushtaqa@pinstech.org.pk; Iqbal, Massod; Bokhari, Ishtiaq Hussain; Mahmood, Tariq; Mahmood, Tayyab; Ahmad, Zahoor; Zaman, Qamar [Nuclear Engineering Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)

    2008-02-15

    Neutronic and thermal hydraulic analysis for the fission molybdenum-99 production at PARR-1 has been performed. Low enriched uranium foil (<20% {sup 235}U) will be used as target material. Annular target designed by ANL (USA) will be irradiated in PARR-1 for the production of 100 Ci of molybdenum-99 at the end of irradiation, which will be sufficient to prepare required {sup 99}Mo/{sup 99m}Tc generators at PINSTECH and its supply in the country. Neutronic and thermal hydraulic analysis were performed using various codes. Data shows that annular targets can be safely irradiated in PARR-1 for production of required amount of fission molybdenum-99.

  10. Thermal steam plasma decomposition of organochlorine compounds

    Science.gov (United States)

    Surov, A. V.; Subbotin, D. I.; Popov, V. E.; Popov, S. D.; Litvyikova, A. I.; Nakonechniy, Gh V.; Serba, E. O.; Obraztsov, N. V.

    2017-11-01

    For the almost complete processing of organochlorine compounds are required a high temperature, hydrogen to produce hydrogen chloride and a high degree of mixing. Reforming chlorobenzene by steam and carbon dioxide in the presence of methane using a three-phase AC plasma torch was carried out. Soot composition was analyzed by energy dispersive X-ray analysis. The yield of soot was 0.84% wt. of raw materials, the content of chlorine in the soot was 2.08% by wt.

  11. A thermal conductivity model for U-­Si compounds

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    U3Si2 is a candidate for accident tolerant nuclear fuel being developed as an alternative to UO2 in commercial light water reactors (LWRs). One of its main benefits compared to UO2 is higher thermal conductivity that increases with temperature. This increase is contrary to UO2, for which the thermal conductivity decreases with temperature. The reason for the difference is the electronic origin of thermal conductivity in U3Si2, as compared to the phonon mechanism responsible for thermal transport in UO2. The phonon thermal conductivity in UO2 is unusually low for a fluorite oxide due to the strong interaction with the spins in the paramagnetic phase. The thermal conductivity of U3Si2 as well as other U-­Si compounds has been measured experimentally [1-­4]. However, for fuel performance simulations it is also critical to model the degradation of the thermal conductivity due to damage and microstructure evolution caused by the reactor environment (irradiation and high temperature). For UO2 this reduction is substantial and it has been the topic of extensive NEAMS research resulting in several publications [5, 6]. There are no data or models for the evolution of the U3Si2 thermal conductivity under irradiation. We know that the intrinsic thermal conductivities of UO2 (semi-conductor) and U3Si2 (metal) are very different, and we do not necessarily expect the dependence on damage to be the same either, which could present another advantage for the silicide fuel. In this report we summarize the first step in developing a model for the thermal conductivity of U-­Si compounds with the goal of capturing the effect of damage in U3Si2. Next year, we will focus on lattice damage. We will also attempt to assess the impact of fission gas bubbles.

  12. Epoxidized natural rubber and hydrotalcite compounds: rheological and thermal characterization

    Directory of Open Access Journals (Sweden)

    Vanessa Macedo da Silva

    2017-09-01

    Full Text Available Abstract Epoxidized natural rubber (ENR and synthetic non-modified hydrotalcite (HT compounds were prepared and evaluated. Natural rubber (NR was epoxidized with 20.6% of epoxy groups from a chemical modification of the latex. A sulfur-based curing system formulation with accelerators was used. The amounts of HT in the ENR-HT compositions was varied between 0, 2, 3 and 5 phr. All compositions were evaluated as to cure parameters, rheological properties, thermal resistance and crosslink density. The results showed that the mineral filler does not have a significant influence on the cure parameters. Different methods of crosslink density determination were used (swelling at equilibrium and elastic modulus. The results turn out to be equivalent and rise as the amount of filler is increased. The best results were found for the 5 phr hydrotalcite compound (ENR-HT5.

  13. Thermolysis kinetics and thermal degradation compounds of alliin.

    Science.gov (United States)

    Chen, Zixing; Xu, MingJiao; Wang, Chao; Zhou, Hua; Fan, Lokyee; Huang, Xuesong

    2017-05-15

    To investigate thermolysis kinetics and identify degradation compounds, alliin solutions were heated at 60, 80, and 89°C. The degradation compounds of alliin were identified by high performance liquid chromatography-mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS) and ultra-pressure liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). The results showed that the thermal degradation kinetic of alliin could be described by a first-order reaction and k=4.38×1017exp (-142494/RT), where k is the reaction rate constant, min-1; R is gas constant; T is the absolute temperature, K. Degraded compounds, including S-allyl-l-cysteine and ethers, such as allyl alanine disulfide, allyl alanine trisulfide, allyl alanine tetrasulfide, dialanine disulfide (cysteine), dialanine trisulfide and dialanine tetrasulfide, were identified by HPLC-MS, MS/MS and UPLC-HRMS. Allyl alanine tetrasulfide was identified for the first time in alliin. The results show that alliin is unstable and significant numbers of organosulfur compounds are generated under high temperature treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. 78 FR 52905 - Low Enriched Uranium From France: Initiation of Expedited Changed Circumstances Review, and...

    Science.gov (United States)

    2013-08-27

    ... uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of less than 20 percent that has not been..., the order does not cover enriched uranium hexafluoride with a U\\235\\ assay of 20 percent or greater... (U 3 O 8 ) with a U\\235\\ concentration of no greater than 0.711 percent and natural uranium...

  15. 77 FR 19642 - Low Enriched Uranium From France: Final Results of Antidumping Duty Changed Circumstances Review

    Science.gov (United States)

    2012-04-02

    ... hexafluoride with a U\\235\\ assay of 20 percent or greater, also known as highly enriched uranium. In addition.... Natural uranium concentrates (U 3 O 8 ) with a U\\235\\ concentration of no greater than 0.711 percent and natural uranium concentrates converted into uranium hexafluoride with a U\\235\\ concentration of no greater...

  16. 77 FR 7128 - Low Enriched Uranium From France: Preliminary Results of Antidumping Duty Changed Circumstances...

    Science.gov (United States)

    2012-02-10

    ... uranium (LEU). LEU is enriched uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of less than 20.... Specifically, the order does not cover enriched uranium hexafluoride with a U\\235\\ assay of 20 percent or... a U\\235\\ concentration of no greater than 0.711 percent and natural uranium concentrates converted...

  17. 78 FR 77650 - Low Enriched Uranium From France: Continuation of Antidumping Duty Order

    Science.gov (United States)

    2013-12-24

    ... hexafluoride with a U\\235\\ assay of 20 percent or greater, also known as highly enriched uranium. In addition.... Natural uranium concentrates (U 3 O 8 ) with a U\\235\\ concentration of no greater than 0.711 percent and natural uranium concentrates converted into uranium hexafluoride with a U\\235\\ concentration of no greater...

  18. 77 FR 1059 - Low Enriched Uranium From France: Initiation of Antidumping Duty Changed Circumstances Review

    Science.gov (United States)

    2012-01-09

    ... enriched uranium hexafluoride (UF 6 ) with a U\\235\\ product assay of less than 20 percent that has not been... cover enriched uranium hexafluoride with a U\\235\\ assay of 20 percent or greater, also known as highly... nuclear fuel rods or assemblies. Natural uranium concentrates (U 3 O 8 ) with a U\\235\\ concentration of no...

  19. Effects study on the thermal stresses in a LEU metal foil annular target.

    Science.gov (United States)

    Govindarajan, Srisharan G; Solbrekken, Gary L

    2015-09-01

    The effects of fission gas pressure, uranium swelling and thermal contact conductance on the thermal-mechanical behavior of an annular target containing a low-enriched uranium foil (LEU) encapsulated in a nickel foil have been presented in this paper. The draw-plug assembly method is simulated to obtain the residual stresses, which are applied to the irradiation model as initial inputs, and the integrated assembly-irradiation process is simulated as an axisymmetric problem using the commercial finite element code Abaqus FEA. Parametric studies were performed on the LEU heat generation rate and the results indicate satisfactory irradiation performance of the annular target. The temperature and stress margins have been provided along with a discussion of the results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. 3D COMSOL Simulations for Thermal Deflection of HFIR Fuel Plate in the "Cheverton-Kelley" Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Prashant K [ORNL; Freels, James D [ORNL; Cook, David Howard [ORNL

    2012-08-01

    Three dimensional simulation capabilities are currently being developed at Oak Ridge National Laboratory using COMSOL Multiphysics, a finite element modeling software, to investigate thermal expansion of High Flux Isotope Reactor (HFIR) s low enriched uranium fuel plates. To validate simulations, 3D models have also been developed for the experimental setup used by Cheverton and Kelley in 1968 to investigate the buckling and thermal deflections of HFIR s highly enriched uranium fuel plates. Results for several simulations are presented in this report, and comparisons with the experimental data are provided when data are available. A close agreement between the simulation results and experimental findings demonstrates that the COMSOL simulations are able to capture the thermal expansion physics accurately and that COMSOL could be deployed as a predictive tool for more advanced computations at realistic HFIR conditions to study temperature-induced fuel plate deflection behavior.

  1. Development of method for identification of compounds emitted during thermal degradation of binders used in foundry

    Directory of Open Access Journals (Sweden)

    A. Bobrowski

    2011-07-01

    Full Text Available The aim of the research was to develop a method for identification of compounds emitted during thermal degradation of binders used in foundry. Research were performed with the use of Certified Reference Materials mixtures of semi-volatiles compounds with furfuryl alcohol and aldehyde. Furfuryl-urea resin samples were also used. Station for thermal degradation of materials used in foundry was designed and made. Thermal degradation process conditions and gas chromatograph coupled with high resolution mass spectrometry operating conditions were established. Organic compounds emitted during degradation were identified. The paper briefly represents the range of study and the results obtained for furfuryl-urea resin thermal degradation. Significant information about volatile and semi-volatile organic compounds emitted in different temperatures is also discussed.

  2. Technical assistance for development of thermally conductive nitride filler for epoxy molding compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Song, Kee Chan; Jung, In Ha

    2005-07-15

    Technical assistance was carried out to develop nitride filler for thermally conductive epoxy molding compounds. Carbothermal reduction method was used to fabricate silicon nitride powder from mixtures of silica and graphite powders. Microstructure and crystal structure were observed by using scanning electron microscopy and x-ray diffraction technique. Thermal properties of epoxy molding compounds containing silicon nitride were measured by using laser flash method. Fabrication process of silicon nitride nanowire was developed and was applied to a patent.

  3. Thermal conductivities study of new types of compound adsorbents used in solar adsorption refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Huizhong [College of Urban Construction and Environment Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China)], E-mail: zhz@usst.edu.cn; Zhang Min [College of Food Science Technology, Shanghai Ocean University, Shanghai 200090 (China); Lv Jing; Yu Guoqing; Zou Zhijun [College of Urban Construction and Environment Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2009-05-15

    In this paper, the thermal probe is firstly introduced and used in adsorption refrigeration to measure the working pair's thermal conductivities. Different types of compound adsorbents were prepared, and the thermal conductivities of all the types were measured with different adsorption capacities. Experimental results demonstrate that: with the same adsorption capacity, the conductivities of the compound adsorbents increase with the quantity of sodium silicate (Na{sub 2}SiO{sub 3}) content. The conductivities of the compound adsorbents increase sharply when the sodium silicate content is between 0% and 7.5% and increase slowly when the content is 7.5-20%. For 13x zeolite and compound adsorbents Z3 and Z4, their thermal conductivities increase as a quadratic polynomial with their adsorption capacities. The conductivities increase more than 158.2% when the adsorption capacities increase from 0% to 25%. The thermal conductivities of compound adsorbent Z3 and Z4 are 0.183 and 0.199 W (m K){sup -1}, respectively, and increase about 65.4% and 80.1%, respectively, compared with the 13x zeolite. With these test results, the compound adsorbent Z4 is used for making an adsorption bed, and the experimental coefficient of performance (COP) of the solar cooling tube is about 0.26.

  4. Thermal Plasma Decomposition Of Nickel And Cobalt Compounds

    Directory of Open Access Journals (Sweden)

    Woch M.

    2015-06-01

    Full Text Available The paper presents the study on manufacturing of nickel and cobalt powders by thermal plasma decomposition of the carbonates of these metals. It was shown the dependence of process parameters and grain size of initial powder on the composition of final product which was ether metal powder, collected in the container as well as the nanopowder with crystallite size of 70 - 90 nm, collected on the inner wall of the reaction chamber. The occurrence of metal oxides in the final products was confirmed and discussed.

  5. Predicting the Thermal Stability of Nitroaromatic Compounds Using Chemoinformatic Tools.

    Science.gov (United States)

    Fayet, Guillaume; Del Rio, Alberto; Rotureau, Patricia; Joubert, Laurent; Adamo, Carlo

    2011-06-01

    In the framework of the European REACH regulation major attention was recently devoted to toxicological and ecotoxicological problems while little attention has been dedicated to other important applications concerning chemical hazards, for instance, explosive properties. In this work different chemoinformatic tools such as partial least squares, multilinear regressions, and decision trees have been used for the development of a novel quantitative structure-property relationships to predict the heat of decomposition of a series of nitroaromatic compounds. Models were conceived in order to follow the regulatory requirements according to OECD principles for the validation of QSAR methods. Three models derived with MLR, PLS and decision tree techniques were developed, validated (internally and externally) and their applicability domains have been defined and analyzed. All models proved to be reliable with remarkable robustness in terms of full cross-validation scheme and showed good predictive power toward the external validation set. These models also present a large applicability domain within nitrobenzene derivatives and are easy to implement and interpret in terms of subjacent mechanisms. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. First Principles Calculations of Electronic and Thermal Properties of AIRE (RE = La, Ce and Pr) Compounds

    Science.gov (United States)

    Srivastava, Vipul; Aynyas, M.; Rajagopalan, M.; Sanyal, S. P.

    2008-04-01

    Electronic properties of non-magnetic cubic B2-type AIRE (RE = La, Ce and Pr) compounds have been derived from self-consistent tight binding linear muffin tin orbital method at ambient pressure. These compounds show metallic behaviour under ambient conditions. While thermal properties like Debye temperature and Grüneisen constant are calculated at T = 0 K within the Debye-Grüneisen model and compared with the others theoretical results. We have also performed a pressure induced variation of Debye temperature. We have found a decrease in Debye temperature around 40 kbar in all the AIRE compounds.

  7. Thermal Conductivity of Compounds Present in the Side Ledge in Aluminium Electrolysis Cells

    Science.gov (United States)

    Gheribi, Aïmen E.; Chartrand, Patrice

    2017-11-01

    This paper presents a database for the temperature-dependent thermal conductivity of compounds potentially present in the side ledge formed in aluminium electrolysis cells, between the molten electrolyte used to dissolve the alumina and the side wall. The database is given in the form of an analytical model with sets of parameters for each compound. To determine the model parameters, we considered a robust optimisation approach based on reliable models derived from fundamental physics. Where data are missing, first-principles calculations are utilized to estimate the parameters directly. For all compounds for which data are available, the model's predictions are found to be in very good agreement with reported experimental data.

  8. Thermal analysis of a compound parabolic concentrator for refrigeration applications

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Naghelli; Best, Roberto [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico)

    2000-07-01

    The refrigeration system designed at the Centro de Investigacion en Energia (CIE), Mexico is able to produce, in optimal conditions, one hundred kilograms per day of ice by means of solar energy. A continuous absorption ammonia-water refrigeration cycle is employed. In its actual state, heat supply to the system is provided through a bank of evacuated tube solar collectors. Their principal difficulties encountered in this system are the indirect heat losses due to the coupling of the falling film generator to the solar heating subsystem that requires a heat transfer gradient and higher collector operating temperatures. Also the high initial cost of the evacuated tube collectors is a barrier for an economical feasible system. Currently, new types of solar collectors are being considered, more efficient and reliable, with a potentially lower cost. This type of collectors known as Compound Parabolic Collectors (CPC) succeed in working at the required temperatures for absorption refrigeration systems. Therefore, a new system is suggested and it is proposed to use a CPC array, where heat losses by the indirect heating system are avoided. In this work a simple method was developed in order to establish the energy balances in a CPC, with a steel tubular receiver without an evacuated glass shell. The receptor's model considers a bidimensional system in stationary state and it supposes a continuous medium. Four nonlinear, simultaneous equations were obtained to predict heat exchange among various components in the system. These equations were utilized in a computer program to analyze the collector performance under various operating conditions. Consequently, the prediction of temperature distribution with respect to position permits to calculate length and arrangement of the CPC for a determined refrigeration application. [Spanish] El sistema de refrigeracion en el Centro de Investigacion en Energia (CIE) Mexico es capaz de producir en condiciones optimas 100

  9. Optimization of Norbornadiene Compounds for Solar Thermal Storage by First-Principles Calculations.

    Science.gov (United States)

    Kuisma, Mikael; Lundin, Angelica; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

    2016-07-21

    Molecular photoswitches capable of storing solar energy are interesting candidates for future renewable energy applications. Here, using quantum mechanical calculations, we carry out a systematic screening of crucial optical (solar spectrum match) and thermal (storage energy density) properties of 64 such compounds based on the norbornadiene-quadricyclane system. Whereas a substantial number of these molecules reach the theoretical maximum solar power conversion efficiency, this requires a strong red-shift of the absorption spectrum, which causes undesirable absorption by the photoisomer as well as reduced thermal stability. These compounds typically also have a large molecular mass, leading to low storage densities. By contrast, single-substituted systems achieve a good compromise between efficiency and storage density, while avoiding competing absorption by the photo-isomer. This establishes guiding principles for the future development of molecular solar thermal storage systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. QSPR modeling of thermal stability of nitroaromatic compounds: DFT vs. AM1 calculated descriptors.

    Science.gov (United States)

    Fayet, Guillaume; Rotureau, Patricia; Joubert, Laurent; Adamo, Carlo

    2010-04-01

    The quantitative structure-property relationship (QSPR) methodology was applied to predict the decomposition enthalpies of 22 nitroaromatic compounds, used as indicators of thermal stability. An extended series of descriptors (constitutional, topological, geometrical charge related and quantum chemical) was calculated at two different levels of theory: density functional theory (DFT) and semi-empirical AM1 approaches. Reliable models have been developed for each level, leading to similar correlations between calculated and experimental data (R(2) > 0.98). Hence, both of them can be employed as screening tools for the prediction of thermal stability of nitroaromatic compounds. If using the AM1 model presents the advantage to be less time consuming, DFT allows the calculation of more accurate molecular quantum properties, e.g., conceptual DFT descriptors. In this study, our best QSPR model is based on such descriptors, providing more chemical comprehensive relationships with decomposition reactivity, a particularly complex property for the specific class of nitroaromatic compounds.

  11. Carcinogenic organic residual compounds readsorbed on thermally reduced graphene materials are released at low temperature.

    Science.gov (United States)

    Ambrosi, Adriano; Wong, Gwendeline K S; Webster, Richard D; Sofer, Zdeněk; Pumera, Martin

    2013-10-18

    The preliminary oxidation of graphite to graphite oxide followed by a thermal exfoliation is one of the methods most frequently employed in the preparation of graphene. Such thermally reduced graphene can be widely used for several applications that range from coatings to sensing device fabrication. It is therefore important to investigate in detail the fabrication procedure, the structural features of the resulting graphene, and its potential toxicological effects. Low-molecular-weight and carcinogenic compounds are known to be generated during the thermal reduction/exfoliation of graphite oxide. Such compounds are readsorbed onto the reduced material during the cooling process. We investigate here the composition of the organic compounds that are adsorbed onto the graphene material and show that they can be easily released during the following processing steps even at temperatures as low as 50 °C. Some of the released organic compounds are classified as highly carcinogenic. The results shown here are important not only from a chemical point of view to better understand the composition and properties of the graphene material produced, but also to bring attention to the potential toxicological effects that the synthesis itself or the post-production processes can cause. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of removal of phenolic compounds on structural and thermal properties of sunflower protein isolate.

    Science.gov (United States)

    Malik, M A; Sharma, H K; Saini, C S

    2016-09-01

    The present study evaluated the effect of removal of polyphenols on the structural properties of protein isolates extracted from sunflower seed and kernel. The structural and thermal changes in protein upon phenolic interaction were studied using circular dichroism, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and Fourier Transform Infrared (FT-IR) spectroscopy. Presence of phenolic compounds in proteins decreased the ordered structure content with parallel increase in unordered structure content. Denaturation temperature was higher for protein isolates with phenolic compounds while, enthalpy decreased upon phenolic interaction. In the presence of phenolic compounds, higher mass loss was observed upon heating. Crystalinity and crystal size got increased after removal of phenolic compounds. Protein isolates from kernels had higher percentage of crystalinity and crystal size as compared to seed protein isolates. Higher molecular weights were observed for protein isolates with phenolic compounds. Presence of polyphenols reduced the hydrophobicity as well the sulfhydryl content and increased the particle size of proteins.

  13. Comparative Ab-Initio Study of Substituted Norbornadiene-Quadricyclane Compounds for Solar Thermal Storage.

    Science.gov (United States)

    Kuisma, Mikael J; Lundin, Angelica M; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

    2016-02-25

    Molecular photoswitches that are capable of storing solar energy, so-called molecular solar thermal storage systems, are interesting candidates for future renewable energy applications. In this context, substituted norbornadiene-quadricyclane systems have received renewed interest due to recent advances in their synthesis. The optical, thermodynamic, and kinetic properties of these systems can vary dramatically depending on the chosen substituents. The molecular design of optimal compounds therefore requires a detailed understanding of the effect of individual substituents as well as their interplay. Here, we model absorption spectra, potential energy storage, and thermal barriers for back-conversion of several substituted systems using both single-reference (density functional theory using PBE, B3LYP, CAM-B3LYP, M06, M06-2x, and M06-L functionals as well as MP2 calculations) and multireference methods (complete active space techniques). Already the diaryl substituted compound displays a strong red-shift compared to the unsubstituted system, which is shown to result from the extension of the conjugated π-system upon substitution. Using specific donor/acceptor groups gives rise to a further albeit relatively smaller red-shift. The calculated storage energy is found to be rather insensitive to the specific substituents, although solvent effects are likely to be important and require further study. The barrier for thermal back-conversion exhibits strong multireference character and as a result is noticeably correlated with the red-shift. Two possible reaction paths for the thermal back-conversion of diaryl substituted quadricyclane are identified and it is shown that among the compounds considered the path via the acceptor side is systematically favored. Finally, the present study establishes the basis for high-throughput screening of norbornadiene-quadricyclane compounds as it provides guidelines for the level of accuracy that can be expected for key properties from

  14. Comparative Ab-Initio Study of Substituted Norbornadiene-Quadricyclane Compounds for Solar Thermal Storage

    OpenAIRE

    Kuisma, Mikael J.; Lundin, Angelica M.; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

    2016-01-01

    Molecular photoswitches that are capable of storing solar energy, so-called molecular solar thermal storage systems, are interesting candidates for future renewable energy applications. In this context, substituted norbornadiene-quadricyclane systems have received renewed interest due to recent advances in their synthesis. The optical, thermodynamic, and kinetic properties of these systems can vary dramatically depending on the chosen substituents. The molecular design of optimal compounds th...

  15. Nanostructure and thermal properties of melt compounded PE/clay nanocomposites filled with an organosilylated montmorillonite

    Science.gov (United States)

    Scarfato, Paola; Incarnato, Loredana; Di Maio, Luciano; Dittrich, Bettina; Niebergall, Ute; Böhning, Martin; Schartel, Bernhard

    2015-12-01

    In this work we report on the functionalization of a natural sodium montmorillonite (MMT) with (3-glycidyloxypropyl)trimethoxysilane by a silylation procedure and on its use as nanofiller in melt compounding of polyethylene nanocomposites. The obtained organosilylated clay showed higher interlayer spacing than the original MMT and higher thermal stability with respect to most of commercial organoclays modified with alkylammonium salts. Its addition (at 5wt%) to two different polyethylene matrices (a low density polyethylene, LDPE, and a high density polyethylene, HDPE), processed in a pilot-scale twin-screw extruder, allowed to produce hybrids with nanoscale dispersion of the filler, as demonstrated by X-ray diffraction. Thermogravimetric and differential scanning thermal analyses point out that the obtained nanocomposites do not show noticeable changes in the thermal behavior of both LDPE and HDPE, even if a slight reduction in the overall bulk crystallinity was observed in presence of the nanofillers.

  16. Investigation of thermodynamic parameters in the thermal decomposition of plastic waste-waste lube oil compounds.

    Science.gov (United States)

    Kim, Yong Sang; Kim, Young Seok; Kim, Sung Hyun

    2010-07-01

    Thermal decomposition properties of plastic waste-waste lube oil compounds were investigated under nonisothermal conditions. Polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) were selected as representative household plastic wastes. A plastic waste mixture (PWM) and waste lube oil (WLO) were mixed with mixing ratios of 33, 50, and 67 (w/w) % on a PWM weight basis, and thermogravimetric (TG) experiments were performed from 25 to 600 degrees C. The Flynn-Wall method and the Ozawa-Flynn-Wall method were used for analyses of thermodynamic parameters. In this study, activation energies of PWM/WLO compounds ranged from 73.4 to 229.6 kJ/mol between 0.2 and 0.8 of normalized mass conversions, and the 50% PWM/WLO compound had lower activation energies and enthalpies among the PWM/WLO samples at each mass conversion. At the point of maximum differential mass conversion, the analyzed activation energies, enthalpies, entropies, and Gibbs free energies indicated that mixing PWM and WLO has advantages in reducing energy to decrease the degree of disorder. However, no difference in overall energy that would require overcoming both thermal decomposition reactions and degree of disorder was observed among PWM/WLO compounds under these experimental conditions.

  17. Electronic and thermal properties of compounds bearing diimide, azomethine and triphenylamine units

    Science.gov (United States)

    Grucela-Zajac, Marzena; Bijak, Katarzyna; Zaleckas, Ernestas; Grigalevicius, Saulius; Wiacek, Malgorzata; Janeczek, Henryk; Schab-Balcerzak, Ewa

    2014-11-01

    New triphenylamine containing azomethine diimides and two kinds of poly(azomethine imide)s, i.e., linear and branched were synthesized. These compounds were prepared from two diamines, that is, N,N‧-bis(4-amino-2,3,5,6-tetramethylphenyl)phtalene-1,2,4,5-dicarboximide (DAPhDI), N,N‧-bis(5-aminonaphtalen)naphthalene-1,4,5,8-dicarboxyimide (DANDI-2) and 4-formyltriphenylamine, 4,4‧-diformyltriphenylamine and 4,4‧,4″-triformyltriphenylamine. The structures of the compounds were characterized by means of FTIR, 1H NMR spectroscopy and elemental analysis; the results show an agreement with the proposed structure. Thermal properties of prepared azomethine diimides and polymers were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Obtained compounds exhibited high thermal stability with 5% weight-loss temperatures above 390 °C. Azomethine diimides exhibited glass-forming properties with high glass-transition temperatures 216 and 308 °C. Optical properties of the prepared compounds were investigated by UV-vis and photoluminescence (PL) measurements. All compounds emitted blue light in NMP solution and in solid state as blend with PMMA. The electrochemical properties, that is, orbital energies and resulting energy gap were estimated based on cyclic voltammetry (CV). All synthesized material showed reversible reduction process, furthermore AzPhDI and AzNDI showed partially reversible oxidation process. Electrochemical band gap was found in the range 1.23-1.70 eV. Low molecular weight model compounds were tested as bipolar host materials in blue phosphorescent organic light emitting diodes (OLEDs). The devices exhibited turn-on voltages of about 5.5 V and maximum brightness of 40-220 cd/m2.

  18. Structure-Activity Relationship Analysis of the Thermal Stabilities of Nitroaromatic Compounds Following Different Decomposition Mechanisms.

    Science.gov (United States)

    Li, Jiazhong; Liu, Huanxiang; Huo, Xing; Gramatica, Paola

    2013-02-01

    The decomposition behavior of energetic materials is very important for the safety problems concerning their production, transportation, use and storage, because molecular decomposition is intimately connected to their explosive properties. Nitroaromatic compounds, particularly nitrobenzene derivatives, are often considered as prototypical energetic molecules, and some of them are commonly used as high explosives. Quantitative structure-activity relationship (QSAR) represents a potential tool for predicting the thermal stability properties of energetic materials. But it is reported that constructing general reliable models to predict their stability and their potential explosive properties is a very difficult task. In this work, we make our efforts to investigate the relationship between the molecular structures and corresponding thermal stabilities of 77 nitrobenzene derivatives with various substituent functional groups (in ortho, meta and/or para positions). The proposed best MLR model, developed by the new software QSARINS, based on Genetic Algorithm for variable selection and with various validation tools, is robust, stable and predictive with R(2) of 0.86, QLOO (2) of 0.79 and CCC of 0.90. The results indicated that, though difficult, it is possible to build predictive, externally validated QSAR models to estimate the thermal stability of nitroaromatic compounds. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Analysis of organic compounds in water by direct adsorption and thermal desorption. [Dissertation

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, J.P. Jr.

    1980-03-01

    An instrument was designed and constructed that makes it possible to thermally desorb organic compounds from wet adsorption traps to a gas chromatograph in an efficient and reproducible manner. Based on this device, a method of analyzing organics in water was developed that is rapid, sensitive, and of broader scope than previously published methods. The system was applied to the analysis of compounds with a wide range of volatilities. Temperature and flow parameters were investigated and specific procedures for quantitation were established. Real samples, including tap water and well water, were also analyzed with this system. Depending on the analysis requirements, the thermal desorption instrument can be used with either packed column or high resolution open-tubular column gas chromatography. The construction plans of normal and high-resolution systems are presented along with chromatograms and data produced by each. Finally, an improved thermal desorption instrument is described. Modifications to the basic system, including splitless injection onto a capillary column, automation, dual cryogenic trapping, reduction of scale, and effluent splitting to dual detection are discussed at length as they relate to the improved instrument.

  20. 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.

  1. Synthesis, characterization and thermal behaviour of solid-state compounds of benzoates with some bivalent transition metal ions

    Directory of Open Access Journals (Sweden)

    Adriano B. Siqueira

    2007-04-01

    Full Text Available Solid-state MBz compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu and Zn and Bz is benzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA, differential scanning calorimetry (DSC, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The procedure used in the preparation of the compounds via reaction of basic carbonates with benzoic acid is not efficient in eliminating excess acid. However the TG-DTA curves permitted to verify that the binary compounds can be obtained by thermosynthesis, because the benzoic acid can be eliminated before the thermal decomposition of these compounds. The results led to information about the composition, dehydration, thermal stability, thermal decomposition and structure of the isolated compounds. On heating, these compounds decompose in two (Mn, Co, Ni, Zn or three (Fe, Cu steps with formation of the respective oxide (Mn3O4, Fe2O3, Co3O4, NiO, CuO and ZnO as final residue. The theoretical and experimental spectroscopic studies suggest a covalent bidentate bond between ligand and metallic center.

  2. Optimization of Mechanical, Dynamical and Thermal Properties of a High Performance Tread Compound for Radial Tires

    Directory of Open Access Journals (Sweden)

    Mir Hamid Reza Ghoreishy

    2013-06-01

    Full Text Available A high performance passenger tire tread compound was optimized for its mechanical, dynamical and thermal properties. A reference compound was based on a blend of SBR and BR, sulfur and other ingredients without accelerator, carbon black and aromatic oil. The effects of CBS/TMTD and TBBS/TMTD as accelerator systems were studied with different quantities and the best accelerator system was chosen. Then, the blends of N330 and N550 carbon blacks were added in different quantities and the properties of these samples were studied to determine the best carbon black blend. Finally, the effect of different quantities of aromatic oil was investigated and the optimized quantity of aromatic oil and the final properties of tire tread compound were defined. The mechanical and dynamical tests were carried out on appropriate samples to determine tensile strength, elongation-at-break, fatigue-to-failure, abrasion resistance, hardness, resilience, dynamical-mechanical properties and temperature rise due to the heat build-up. The results showed that the compound containing 0.8 phr CBS, 0.7 phr TMTD, 40 phr N330,20 phr N550 and 15 phr aromatic oils demonstrated the best properties.

  3. Simulation of Low-Enriched Uranium (LEU) Burnup in Russian VVER Reactors with the HELIOS Code Package

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, B.D.; Kravchenko, J.; Lazarenko, A.; Pavlovitchev, A.; Sidorenko, V.; Chetverikov, A.

    2000-03-01

    The HELIOS reactor-physics computer program system was used to simulate the burnup of UO{sub 2} fuel in three VVER reactors. The manner in which HELIOS was used in these simulations is described. Predictions of concentrations for actinides up to {sup 244}Cm and for isotopes of neodymium were compared with laboratory-measured values. Reasonable agreement between calculated and measured values was seen for experimental samples from a fuel rod in the interior of an assembly.

  4. 78 FR 21100 - Low Enriched Uranium From France: Final Results of the Expedited Second Sunset Review of the...

    Science.gov (United States)

    2013-04-09

    ... hexafluoride with a U\\235\\ assay of 20 percent or greater, also known as highly enriched uranium. In addition.... Natural uranium concentrates (U 3 O 8 ) with a U\\235\\ concentration of no greater than 0.711 percent and natural uranium concentrates converted into uranium hexafluoride with a U\\235\\ concentration of no greater...

  5. Compound

    Indian Academy of Sciences (India)

    UV-vis spectra showing solvent effects on compounds (6). Figure S4. UV-vis spectra showing solvent effects on compounds (9). Figure S5. UV-vis spectra showing solvent ___, acidic--- and basic -□- effects on compound (8) in CH2Cl2 solution. Table S1. 1H and 13C NMR spectral data of salicylaldimine Schiff bases (5-8).

  6. Theoretical studies on thermal degradation reaction mechanism of model compound of bisphenol A polycarbonate.

    Science.gov (United States)

    Huang, Jinbao; He, Chao; Li, Xinsheng; Pan, Guiying; Tong, Hong

    2018-01-01

    Density functional theory methods (DFT) M062X have been used to investigate the thermal degradation processes of model compound of bisphenol A polycarbonate (MPC) and to identify the optimal reaction paths in the thermal decomposition of bisphenol A polycarbonate (PC). The bond dissociation energies of main bonds in MPC were calculated, and it is found that the weakest bond in MPC is the single bond between the methylic carbon and carbon atom and the second weakest bond in MPC is the single bond between oxygen atom and the carbonyl carbon. On the basis of computational results of kinetic parameters, a mechanism is proposed where the hydrolysis (or alcoholysis) reaction is the main degradation pathways for the formation of the evolved products, and the homolytic cleavage and rearrangement reactions are the competitive reaction pathways in the thermal degradation of PC. The proposed mechanism is consistent with experimental observations of CO2, bisphenol A and 1,1-bis(4-hydroxyphenyl)-ethane as the main degradation products, together with a small amount of CO, alkyl phenol and diphenyl carbonate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. MECHANICAL AND THERMAL PROPERTIES OF WASTE BIO-POLYMER COMPOUND BY HOT COMPRESSION MOLDING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    M. Khairul Zaimy A. G.

    2013-12-01

    Full Text Available The demand for bio-polymer compound (BPC has attracted attention in various applications from industrial to medical. Therefore, the mechanical and thermal stability properties of recycling industrial waste BPC are very important to investigate. The waste BPC for this study is based on a mixture of hydroxylated waste cooking oil with hardeners to produce waste bio-polymer foam (WBF. The granulate of WBF was cast into the mold until all spaces were evenly filled and compacted into a homogeneous shape and thickness at 30–45 bar for 2 hours using hot compression molding. This method of BPC fabrication results in a tensile and flexural strength of 4.89 MPa and 18.08 MPa respectively. Meanwhile, the thermal stability of laminated BPC was conducted using a thermal gravimetric analyzer (TGA, and the first degradation of the soft segment occurred at 263°C, then subsequently the second degradation occurred at 351°C and the last at 416°C.

  8. Analysis of the Compounds from the BTEX Group, Emitted During Thermal Decomposition of Alkyd Resin

    Directory of Open Access Journals (Sweden)

    M. Kubecki

    2012-09-01

    Full Text Available Suitability of the given binding agent for the moulding sands preparation depends on the one hand on the estimation of technological properties of the sand and the mould made of it and the obtained casting quality and on the other hand on the assessment of this sand influence on the natural and working environment. Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin (phenol-formaldehyde, urea, furfuryl, urea–furfuryl, alkyd under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene, and also polycyclic aromatic hydrocarbons (PAH can be formed and released.The aim of the study was the development of the method, selection of analytical methods and the determination of optimal conditionsof formation compounds from the BTEX group. An emission of these components constitutes one of the basic criteria of the harmfulnessassessment of binders applied for moulding and core sands. Investigations were carried out in the specially designed set up for the thermal decomposition of organic substances in a temperature range: 5000C – 13000C at the laboratory scale. The object for testing was alkyd resin applied as a binding material for moulding sands. Within investigations the minimal amount of adsorbent necessary for the adsorption of compounds released during the decomposition of the resin sample of a mass app. 15 mg was selected. Also the minimal amount of solvent needed for

  9. Thermal and oxidation stability of organo-fluorine compound-mixed electrolyte solutions for lithium ion batteries

    Science.gov (United States)

    Nishikawa, Daiki; Nakajima, Tsuyoshi; Ohzawa, Yoshimi; Koh, Meiten; Yamauchi, Akiyoshi; Kagawa, Michiru; Aoyama, Hirokazu

    2013-12-01

    Thermal and oxidation stability of fluorine compound-mixed electrolyte solutions have been investigated. Charge/discharge behavior of natural graphite electrode has been also examined in the same electrolyte solutions. Fluorine compounds demonstrate much lower reactivity with metallic Li than ethylene carbonate/dimethyl carbonate. Fluorine compound-mixed electrolyte solutions show the lower reactivity with LiC6 and the smaller exothermic peaks due to decomposition of electrolyte solutions and surface films than original solutions without fluorine compound. Oxidation currents are also smaller in fluorine compound-mixed electrolyte solutions than in original ones. First coulombic efficiencies in fluorine compound-mixed electrolyte solutions are similar to those in original ethylene carbonate-based solutions except one case. Mixing of fluorine compounds highly increase first coulombic efficiencies of natural graphite electrode in propylene carbonate-containing solution.

  10. Thermal Decomposition Mechanisms of Lignin Model Compounds: From Phenol to Vanillin

    Science.gov (United States)

    Scheer, Adam Michael

    Lignin is a complex, aromatic polymer abundant in cellulosic biomass (trees, switchgrass etc.). Thermochemical breakdown of lignin for liquid fuel production results in undesirable polycyclic aromatic hydrocarbons that lead to tar and soot byproducts. The fundamental chemistry governing these processes is not well understood. We have studied the unimolecular thermal decomposition mechanisms of aromatic lignin model compounds using a miniature SiC tubular reactor. Products are detected and characterized using time-of-flight mass spectrometry with both single photon (118.2 nm; 10.487 eV) and 1 + 1 resonance-enhanced multiphoton ionization (REMPI) as well as matrix isolation infrared spectroscopy. Gas exiting the heated reactor (300 K--1600 K) is subject to a free expansion after a residence time of approximately 100 micros. The expansion into vacuum rapidly cools the gas mixture and allows the detection of radicals and other highly reactive intermediates. By understanding the unimolecular fragmentation patterns of phenol (C6H5OH), anisole (C6H 5OCH3) and benzaldehyde (C6H5CHO), the more complicated thermocracking processes of the catechols (HO-C 6H4-OH), methoxyphenols (HO-C6H4-OCH 3) and hydroxybenzaldehydes (HO-C6H4-CHO) can be interpreted. These studies have resulted in a predictive model that allows the interpretation of vanillin, a complex phenolic ether containing methoxy, hydroxy and aldehyde functional groups. This model will serve as a guide for the pyrolyses of larger systems including lignin monomers such as coniferyl alcohol. The pyrolysis mechanisms of the dimethoxybenzenes (H3C-C 6H4-OCH3) and syringol, a hydroxydimethoxybenzene have also been studied. These results will aid in the understanding of the thermal fragmentation of sinapyl alcohol, the most complex lignin monomer. In addition to the model compound work, pyrolyisis of biomass has been studied via the pulsed laser ablation of poplar wood. With the REMPI scheme, aromatic lignin decomposition

  11. Morphology, thermal and mechanical properties of PVC/MMT nanocomposites prepared by solution blending and solution blending + melt compounding

    DEFF Research Database (Denmark)

    Madaleno, Liliana Andreia Oliveira; Schjødt-Thomsen, Jan; Pinto, José Cruz

    2010-01-01

    and solution blending + melt compounding The effects on morphology, thermal and mechanical properties of the PVC/MMT nanocomposites were studied by varying the amount of Na-MMT and OMMT in both methods SEM and XRD analysis revealed that possible intercalated and exfoliated structures were obtained in all...... of the PVC/MMT nanocomposites Thermogravimetric analysis revealed that PVC/Na-MMT nanocomposites have better thermal stability than PVC/OMMT nanocomposites and PVC. In general, PVC/MMT nanocomposites prepared by solution blending + melt compounding revealed improved thermal properties compared to PVC....../MMT nanocomposites prepared by solution blending Vicar tests revealed a significant decrease in Vicar softening temperature of PVC/MMT nanocomposites prepared by solution blending + melt compounding compared to unfilled PVC The mechanical properties of the PVC/MMT nanocomposites were, in general, greatly improved...

  12. Comparative Performance of Three Magnesium Compounds on Thermal Degradation Behavior of Red Gum Wood

    Directory of Open Access Journals (Sweden)

    Yiqiang Wu

    2014-01-01

    Full Text Available The effect of basic magnesium carbonate (BMC, magnesium hydroxide (MH, and magnesium chloride hydrate (MCH on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC analysis, and X-ray diffraction (XRD characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270 °C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg2+ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167 °C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction.

  13. Evaluation of bioactive compounds of black mulberry juice after thermal, microwave, ultrasonic processing, and storage at different temperatures.

    Science.gov (United States)

    Jiang, Bo; Mantri, Nitin; Hu, Ya; Lu, Jiayin; Jiang, Wu; Lu, Hongfei

    2015-07-01

    The effect of different sterilization methods (thermal, microwave, and ultrasonic processing) on the main bioactive compounds and antioxidant activity of black mulberry juice during selected storage time (8 days) and temperatures (5, 15, and 25 ℃) was investigated. The antioxidant activity of thermal-treated juice depleted with storage time, whilst both ultrasound- and microwave-treated juices showed transient increase in antioxidant activity during the first 2 days that later decreased with storage time. Lower temperature storage preserved more bioactive compounds and antioxidant activity, especially in ultrasound sterilized samples. The activation energy values were 15.99, 13.07, and 12.81 kJ/mol for ultrasonic, microwave, and thermal pasteurization processes, respectively. In general, ultrasound-sterilized samples showed higher total phenolics, anthocyanin, and antioxidant activity compared to the microwave- and thermal-processed juice during the storage time especially at lower temperatures. © The Author(s) 2014.

  14. Effects of high hydrostatic pressure and thermal processing on bioactive compounds, antioxidant activity, and volatile profile of mulberry juice.

    Science.gov (United States)

    Wang, Fan; Du, Bao-Lei; Cui, Zheng-Wei; Xu, Li-Ping; Li, Chun-Yang

    2017-03-01

    The aim of this study was to investigate the effects of high hydrostatic pressure and thermal processing on microbiological quality, bioactive compounds, antioxidant activity, and volatile profile of mulberry juice. High hydrostatic pressure processing at 500 MPa for 10 min reduced the total viable count from 4.38 log cfu/ml to nondetectable level and completely inactivated yeasts and molds in raw mulberry juice, ensuring the microbiological safety as thermal processing at 85 ℃ for 15 min. High hydrostatic pressure processing maintained significantly (p pressure processing enhanced the volatile compound concentrations of mulberry juice while thermal processing reduced them in comparison with the control. These results suggested that high hydrostatic pressure processing could be an alternative to conventional thermal processing for production of high-quality mulberry juice.

  15. On the prediction of thermal stability of nitroaromatic compounds using quantum chemical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Fayet, Guillaume [Laboratoire d' Electrochimie et Chimie Analytique, CNRS UMR-7575, Ecole Nationale Superieure de Chimie de Paris, 11 rue P. et M. Curie, 75231 Paris Cedex 05 (France); Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, 60550 Verneuil-en-Halatte (France); Rotureau, Patricia, E-mail: patricia.rotureau@ineris.fr [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, 60550 Verneuil-en-Halatte (France); Joubert, Laurent; Adamo, Carlo [Laboratoire d' Electrochimie et Chimie Analytique, CNRS UMR-7575, Ecole Nationale Superieure de Chimie de Paris, 11 rue P. et M. Curie, 75231 Paris Cedex 05 (France)

    2009-11-15

    This work presents a new approach to predict thermal stability of nitroaromatic compounds based on quantum chemical calculations and on quantitative structure-property relationship (QSPR) methods. The data set consists of 22 nitroaromatic compounds of known decomposition enthalpy (taken as a macroscopic property related to explosibility) obtained from differential scanning calorimetry. Geometric, electronic and energetic descriptors have been selected and computed using density functional theory (DFT) calculation to describe the 22 molecules. First approach consisted in looking at their linear correlations with the experimental decomposition enthalpy. Molecular weight, electrophilicity index, electron affinity and oxygen balance appeared as the most correlated descriptors (respectively R{sup 2} = 0.76, 0.75, 0.71 and 0.64). Then multilinear regression was computed with these descriptors. The obtained model is a six-parameter equation containing descriptors all issued from quantum chemical calculations. The prediction is satisfactory with a correlation coefficient R{sup 2} of 0.91 and a predictivity coefficient R{sub cv}{sup 2} of 0.84 using a cross validation method.

  16. On the prediction of thermal stability of nitroaromatic compounds using quantum chemical calculations.

    Science.gov (United States)

    Fayet, Guillaume; Rotureau, Patricia; Joubert, Laurent; Adamo, Carlo

    2009-11-15

    This work presents a new approach to predict thermal stability of nitroaromatic compounds based on quantum chemical calculations and on quantitative structure-property relationship (QSPR) methods. The data set consists of 22 nitroaromatic compounds of known decomposition enthalpy (taken as a macroscopic property related to explosibility) obtained from differential scanning calorimetry. Geometric, electronic and energetic descriptors have been selected and computed using density functional theory (DFT) calculation to describe the 22 molecules. First approach consisted in looking at their linear correlations with the experimental decomposition enthalpy. Molecular weight, electrophilicity index, electron affinity and oxygen balance appeared as the most correlated descriptors (respectively R(2)=0.76, 0.75, 0.71 and 0.64). Then multilinear regression was computed with these descriptors. The obtained model is a six-parameter equation containing descriptors all issued from quantum chemical calculations. The prediction is satisfactory with a correlation coefficient R(2) of 0.91 and a predictivity coefficient R(cv)(2) of 0.84 using a cross validation method.

  17. Infrared Active Phonons in the Negative Thermal Expanding Compound, ZrW2O8

    Science.gov (United States)

    Turpen, Chandra; Hancock, Jason N.; Schlesinger, Zack; Kowach, Glen

    2003-03-01

    ZrW_2O8 is unusual in that it contracts as it is heated, a phenomenon known as negative thermal expansion. We will present studies of infrared reflectivity and conductivity vs. frequency for a pressed pellet sample of ZrW_2O_8, a compound with cubic lattice structure. Our measurements range from 20 K up to room temperature and from 12 cm-1 to 5000 cm-1 encompassing the entire range of the infrared active phonons in ZrW_2O_8. The phonon spectra exhibit considerable temperature dependence, particularly at low frequency. It is of interest to note that our infrared measurements show two regions of strong absorption in frequency ranges where the phonon density-of-states inferred from time-of-flight neutron scattering is very low. We will compare IR results with other measurements and discuss implications for understanding the nature of this unusual compound. This material is based upon work supported by the National Science Foundation under Grant No. DMR-0071949.

  18. Thermal behavior and spectroscopic study of neutral and cationic mononuclear cyclopalladated compounds

    Directory of Open Access Journals (Sweden)

    Ananias Sandra R.

    2003-01-01

    Full Text Available The reactions of the precursor [Pd(N,C-dmba(MeCN2](NO3 (1 (dmba = N,N-dimethylbenzylamine, with the proligands 3,5-dimethylpyrazole (Hdmpz, 2-quinolinethiol (qnSH and 1,1'-bis(diphenylphosphineferrocene (dppf afforded the compounds [Pd(N,C-dmba(Hdmpz(ONO2]0.5CH2 Cl2 (2, [Pd(N,C-dmba(qnSH(ONO2] 0.5CH2Cl2 (3 and [Pd(N,C-dmba(dppf](NO3 (4, respectively. The mononuclear species 2, 3 and 4 were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR spectra show bands which are consistent with terminal monodentate nitrate group for 2-3 and ionic nitrate for 4. The ¹H and 13C NMR data confirm that coordination of the organic ligands has occurred and the 31P{¹H} NMR data for 4 clearly evidences the occurrence in solution of three cyclopalladated species with the dppf acting as a bridging ligand in two cases and as a chelate in one. The thermal behavior of compounds 1-4 suggests that complex 2 is the most stable. The X-ray diffractometry results show the formation of PdO from 1 and 2, Pd2OSO4 from 3, and of a mixture of PdO and Fe2(PO43 from 4, as final decomposition products.

  19. Thermal and structural study on the lattice compound 1,4-diammoniumbutane bis(theophyllinate)

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Margit; Madarasz, Janos; Bombicz, Petra; Pokol, Gyoergy; Gal, Sandor

    2004-10-01

    Crystalline title compound (1) prepared from aqueous solution of theophylline and 1,4-diaminobutane has been structurally and thermally characterized. Both the two-step TG decomposition curve and elemental analysis of the hexagonal crystals show that it consists of theophylline and 1,4-diaminobutane in 2:1 molar ratio. Actually, presence of one type of both theophyllinate anions and 1,4-diammoniumbutane dication have been indicated by FTIR spectroscopy. The molecular structure of lattice compound (1) has been determined by single crystal X-ray diffraction, where the hydrogen positions have been obtained from differential Fourier maps. It has confirmed that the crystal is really built up from these ionic constituents bound together with an extensive net of hydrogen bonds. The coupled TG-FTIR analysis of the evolved gases has revealed that the diamine is released as a whole molecule in the first decomposition step. Clathrate 1 and the proton migration in it might serve as a structural model of solid aminophylline whose crystal structure is still unknown.

  20. Stabilities of tocopherols and phenolic compounds in virgin olive oil during thermal oxidation.

    Science.gov (United States)

    Yalcin, Seda; Schreiner, Matthias

    2018-01-01

    The effects of thermal oxidation at 60 °C on tocopherols (α, β, γ) and phenolic compounds (hydroxytyrosol and tyrosol) of olive oil were studied. Tocopherols were determined by HPLC and phenolic compounds by HPLC and GC-MS. Peroxide value of olive oil increased with treatment time until it reached to 56.6 meq/kg. α-Tocopherol, β-tocopherol and γ-tocopherol contents of olive oil decreased with treatment time. α-Tocopherol in olive oil was decomposed after 63 days of treatment. β-Tocopherol in olive oil was depleted after 33 days of treatment. The reduction in γ-tocopherol of olive oil was 75% after 63 days of treatment. The degradation of hydroxytyrosol in olive oil was 91% after 63 days of treatment. Tyrosol was more stable than hydroxytyrosol in olive oil. Inverse correlations of peroxide value with hydroxytyrosol, α-Tocopherol, β-tocopherol and γ-tocopherol were observed.

  1. Increase in the specific radioactivity of tritium-labeled compounds obtained by tritium thermal activation method

    Energy Technology Data Exchange (ETDEWEB)

    Badun, G.A.; Chernysheva, M.G. [Lomonosov Moscow State Univ., Moscow (Russian Federation). Radiochemistry Div.; Ksenofontov, A.L. [Lomonosov Moscow State Univ., Moscow (Russian Federation). N. Belozersky Institute of Physico-Chemical Biology

    2012-07-01

    A method of tritium introduction into different types of organic molecules that is based on the interaction of atomic tritium with solid organic target is described. Tritium atoms are formed on the hot W-wire, which is heated by the electric current. Such an approach is called 'tritium thermal activation method'. Here we summarize the results of labeling globular proteins (lysozyme, human and bovine serum albumins); derivatives of pantothenic acid and amino acids; ionic surfactants (sodium dodecylsulfate and alkyltrimethylammonium bromides) and nonionic high-molecular weight surfactants - pluronics. For the first time it is observed that if the target-compound is fixed and its radicals are stable the specific radioactivity of the labeled product can be drastically increased (up to 400 times) when the target temperature is ca. 295 K compared with the results obtained at 77 K. The influence of labeling parameters as tritium gas pressure, exposure time and W-wire temperature was tested for each target temperature that results in the optimum labeling conditions with high specific radioactivity and chemical yield of the resulting compound. (orig.)

  2. Fuel Thermo-physical Characterization Project: Evaluation of Models to Calculate Thermal Diffusivity of Layered Composites

    Energy Technology Data Exchange (ETDEWEB)

    Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Casella, Amanda J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gardner, Levi D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Casella, Andrew M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huber, Tanja K. [Technische Universität München, Munich (Germany); Breitkreutz, Harald [Technische Universität München, Munich (Germany)

    2015-02-11

    The Office of Material Management and Minimization Fuel Thermo-physical Characterization Project at Pacific Northwest National Laboratory (PNNL) is tasked with using PNNL facilities and processes to receive irradiated low enriched uranium-molybdenum fuel plate samples and perform analyses in support of the Office of Material Management and Minimization Reactor Conversion Program. This work is in support of the Fuel Development Pillar that is managed by Idaho National Laboratory. A key portion of the scope associated with this project was to measure the thermal properties of fuel segments harvested from plates that were irradiated in the Advanced Test Reactor. Thermal diffusivity of samples prepared from the fuel segments was measured using laser flash analysis. Two models, one developed by PNNL and the other developed by the Technische Universität München (TUM), were evaluated to extract the thermal diffusivity of the uranium-molybdenum alloy from measurements made on the irradiated, layered composites. The experimental data of the “TC” irradiated fuel segment was evaluated using both models considering a three-layer and five-layer system. Both models are in acceptable agreement with one another and indicate that the zirconium diffusion barrier has a minimal impact on the overall thermal diffusivity of the monolithic U-Mo fuel.

  3. Retrofitting of compound systems of thermal insulation. Mantle on the jacket; Sanierung von WDVS durch Aufdoppelung. Mantel ueber der Jacke

    Energy Technology Data Exchange (ETDEWEB)

    Siegele, Klaus

    2011-03-15

    More than thirty years ago the era of compound systems of thermal insulation started - using five to eight centimetres thin polystyrene insulation panels, in the 1970ies the pioneers of the facade insulation responded to the dictation of the oil sheik and set thereby the course for the development of an energy efficient design for the first time. In the meantime the thermoskins of the first hour lost some of its shine and also correspond no more to the today's insulation standard. Their retrofitting lines up. Thus the question arises: Demolition, disposal and assembly of a new compound system of thermal insulation? Or are panels the better solution?.

  4. Impact of organic-mineral matter interactions on thermal reaction pathways for coal model compounds

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, A.C. III; Britt, P.F.; Struss, J.A. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

    1995-07-01

    Coal is a complex, heterogeneous solid that includes interdispersed mineral matter. However, knowledge of organic-mineral matter interactions is embryonic, and the impact of these interactions on coal pyrolysis and liquefaction is incomplete. Clay minerals, for example, are known to be effective catalysts for organic reactions. Furthermore, clays such as montmorillonite have been proposed to be key catalysts in the thermal alteration of lignin into vitrinite during the coalification process. Recent studies by Hatcher and coworkers on the evolution of coalified woods using microscopy and NMR have led them to propose selective, acid-catalyzed, solid state reaction chemistry to account for retained structural integrity in the wood. However, the chemical feasibility of such reactions in relevant solids is difficult to demonstrate. The authors have begun a model compound study to gain a better molecular level understanding of the effects in the solid state of organic-mineral matter interactions relevant to both coal formation and processing. To satisfy the need for model compounds that remain nonvolatile solids at temperatures ranging to 450 C, model compounds are employed that are chemically bound to the surface of a fumed silica (Si-O-C{sub aryl}linkage). The organic structures currently under investigation are phenethyl phenyl ether (C{sub 6}H{sub 5}CH{sub 2}CH{sub 2}OC{sub 6}H{sub 5}) derivatives, which serve as models for {beta}-alkyl aryl ether units that are present in lignin and lignitic coals. The solid-state chemistry of these materials at 200--450 C in the presence of interdispersed acid catalysts such as small particle size silica-aluminas and montmorillonite clay will be reported. Initial focus will be on defining the potential impact of these interactions on coal pyrolysis and liquefaction.

  5. Nuclear Thermal Propulsion Development Risks

    Science.gov (United States)

    Kim, Tony

    2015-01-01

    There are clear advantages of development of a Nuclear Thermal Propulsion (NTP) for a crewed mission to Mars. NTP for in-space propulsion enables more ambitious space missions by providing high thrust at high specific impulse ((is) approximately 900 sec) that is 2 times the best theoretical performance possible for chemical rockets. Missions can be optimized for maximum payload capability to take more payload with reduced total mass to orbit; saving cost on reduction of the number of launch vehicles needed. Or missions can be optimized to minimize trip time significantly to reduce the deep space radiation exposure to the crew. NTR propulsion technology is a game changer for space exploration to Mars and beyond. However, 'NUCLEAR' is a word that is feared and vilified by some groups and the hostility towards development of any nuclear systems can meet great opposition by the public as well as from national leaders and people in authority. The public often associates the 'nuclear' word with weapons of mass destruction. The development NTP is at risk due to unwarranted public fears and clear honest communication of nuclear safety will be critical to the success of the development of the NTP technology. Reducing cost to NTP development is critical to its acceptance and funding. In the past, highly inflated cost estimates of a full-scale development nuclear engine due to Category I nuclear security requirements and costly regulatory requirements have put the NTP technology as a low priority. Innovative approaches utilizing low enriched uranium (LEU). Even though NTP can be a small source of radiation to the crew, NTP can facilitate significant reduction of crew exposure to solar and cosmic radiation by reducing trip times by 3-4 months. Current Human Mars Mission (HMM) trajectories with conventional propulsion systems and fuel-efficient transfer orbits exceed astronaut radiation exposure limits. Utilizing extra propellant from one additional SLS launch and available

  6. Effects of thermal maturation and thermochemical sulfate reduction on compound-specific sulfur isotopic compositions of organosulfur compounds in Phosphoria oils from the Bighorn Basin, USA

    Science.gov (United States)

    Ellis, Geoffrey S.; Said-Ahamed, Ward; Lillis, Paul G.; Shawar, Lubna; Amrani, Alon

    2017-01-01

    Compound-specific sulfur isotope analysis was applied to a suite of 18 crude oils generated from the Permian Phosphoria Formation in the Bighorn Basin, western USA. These oils were generated at various levels of thermal maturity and some experienced thermochemical sulfate reduction (TSR). This is the first study to examine the effects of thermal maturation on stable sulfur isotopic compositions of individual organosulfur compounds (OSCs) in crude oil. A general trend of 34S enrichment in all of the studied compounds with increasing thermal maturity was observed, with the δ34S values of alkyl-benzothiophenes (BTs) tending to be enriched in 34S relative to those of the alkyl-dibenzothiophenes (DBTs) in lower-maturity oils. As thermal maturity increases, δ34S values of both BTs and DBTs become progressively heavier, but the difference in the average δ34S value of the BTs and DBTs (Δ34S BT-DBT) decreases. Differences in the isotopic response to thermal stress exhibited by these two compound classes are considered to be the result of relative differences in their thermal stabilities. TSR-altered Bighorn Basin oils have OSCs that are generally enriched in 34S relative to non-TSR-altered oils, with the BTs being enriched in 34S relative to the DBTs, similar to the findings of previous studies. However, several oils that were previously interpreted to have been exposed to minor TSR have Δ34S BT-DBT values that do not support this interpretation. The δ34S values of the BTs and DBTs in some of these oils suggest that they did not experience TSR, but were derived from a more thermally mature source. The heaviest δ34S values observed in the OSCs are enriched in 34S by up to 10‰ relative to that of Permian anhydrite in the Bighorn Basin, suggesting that there may be an alternate or additional source of sulfate in some parts of the basin. These results indicate that the sulfur isotopic composition of OSCs in oil provides a sensitive indicator for the extent of TSR

  7. Endogenous functional compounds in Korean native chicken meat are dependent on sex, thermal processing and meat cut.

    Science.gov (United States)

    Jayasena, Dinesh D; Jung, Samooel; Kim, Sun Hyo; Kim, Hyun Joo; Alahakoon, Amali U; Lee, Jun Heon; Jo, Cheorun

    2015-03-15

    In this study the effects of sex, meat cut and thermal processing on the carnosine, anserine, creatine, betaine and carnitine contents of Korean native chicken (KNC) meat were determined. Forty 1-day-old chicks (20 chicks of each sex) from a commercial KNC strain (Woorimatdag™) were reared under similar standard commercial conditions with similar diets, and ten birds of each sex were randomly selected and slaughtered at 14 weeks of age. Raw and cooked meat samples were prepared from both breast and leg meats and analyzed for the aforementioned functional compounds. Female KNCs had significantly higher betaine and creatine contents. The breast meat showed significantly higher carnosine and anserine contents, whereas the leg meat had a higher betaine and carnitine content. The content of all functional compounds was significantly depleted by thermal processing. This study confirms that KNC meat is a good source of the above-mentioned functional compounds, which can be considered attractive nutritional quality factors. However, their concentrations were significantly affected by thermal processing conditions, meat cut and sex. Further experiments are needed to select the best thermal processing method to preserve these functional compounds. © 2014 Society of Chemical Industry.

  8. Development of a general model for determination of thermal conductivity of liquid chemical compounds at atmospheric pressure

    DEFF Research Database (Denmark)

    Gharagheizi, Farhad; Ilani‐Kashkouli, Poorandokht; Sattari, Mehdi

    2013-01-01

    In this communication, a general model for representation/presentation of the liquid thermal conductivity of chemical compounds (mostly organic) at 1 atm pressure for temperatures below normal boiling point and at saturation pressure for temperatures above the normal boiling point is developed us...

  9. Volatile organic compounds (VOCs) removal in non-thermal plasma double dielectric barrier discharge reactor.

    Science.gov (United States)

    Mustafa, Muhammad Farooq; Fu, Xindi; Liu, Yanjun; Abbas, Yawar; Wang, Hongtao; Lu, Wenjing

    2018-04-05

    Non-thermal plasma (NTP) an emerging technology to treat volatile organic compounds (VOCs) present in unhygienic point source air streams. In present study, double dielectric barrier discharge (DDBD) reactors were used for the first time to evaluate the removal efficiency of VOCs mixture of different nature at constant experimental conditions (input power 16-65.8 W, VOCs mixture feeding rate 1-6 L/min, 100-101 ppm inlet concentration of individual VOC). Reactor A and B with discharge gap at 6 mm and 3 mm respectively, were used in current study. When treated at an input power of 53.7 W with gas feeding rate of 1 L/min in DDBD reactor A, removal efficiency of the VOCs were: tetrachloroethylene (100%), toluene (100%), trichloroethylene (100%), benzene (100%), ethyl acetate (100%) and carbon disulfide (88.30%); whereas in reactor B, the removal efficiency of all VOCs were 100%. Plasma-catalyst (Pt-Sn/Al 2 O 3 , BaTiO 3 and HZSM-5) synergistic effect on VOCs removal efficiency was also investigated. Highest removal efficiency i.e 100% was observed for each compound with BaTiO 3 and HZSM-5 at an input power 65.8 W. However, integrating NTP with BaTiO 3 and HZSM-5 leads to enhanced removal performance of VOCs mixture with high activity, increase in energy efficiency and suppression of unwanted byproducts. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Biochemical degradation and physical migration of polyphenolic compounds in osmotic dehydrated blueberries with pulsed electric field and thermal pretreatments.

    Science.gov (United States)

    Yu, Yuanshan; Jin, Tony Z; Fan, Xuetong; Wu, Jijun

    2018-01-15

    Fresh blueberries were pretreated by pulsed electric fields (PEF) or thermal pretreatment and then were subject to osmotic dehydration. The changes in contents of anthocyanins, predominantly phenolic acids and flavonols, total phenolics, polyphenol oxidase (PPO) activity and antioxidant activity in the blueberry samples during pretreatment and osmotic dehydration were investigated. Biochemical degradation and physical migration of these nutritive compounds from fruits to osmotic solutions were observed during the pretreatments and osmotic dehydration. PEF pretreated samples had the least degradation loss but the most migration loss of these compounds compared to thermally pretreated and control samples. Higher rates of water loss and solid gain during osmotic dehydration were also obtained by PEF pretreatment, reducing the dehydration time from 130 to 48h. PEF pretreated and dehydrated fruits showed superior appearance to thermally pretreated and control samples. Therefore, PEF pretreatment is a preferred technology that balances nutritive quality, appearance, and dehydration rate. Published by Elsevier Ltd.

  11. Thermal design of a modern, two floor, zero energy house in a desert compound

    KAUST Repository

    Serag-Eldin, M. A.

    2010-12-01

    The paper presents a thermal analysis and design of a fully equipped, air-conditioned, zero energy house located in a desert compound at 24.5° latitude. Unlike previous designs the home is two floors high, which makes the balancing of energy supply and demand even more challenging. The roof of the house carries an array of retractable Photovoltaic modules and cover. During day light hours the modules convert the incident sun energy into useful electrical power, while shielding the roof from direct sun-radiation. At night time, the roof cover and modules are retracted to expose the roof to the cool night-sky, thus enhancing cooling. The paper employs time-dependent modeling of Solar input and heat transfer to predict the roof, wall and window temperature distributions and cooling loads, as well as energy generated by the modules. With the aid of battery storage, the modules provide the entire energy needs of the house. The paper displays the results of energy balances for three key days of the year which demonstrate that the proposed two floor design is indeed capable of operating without external energy. © 2010 IEEE.

  12. Gamma-radiation effect on thermal ageing of butyl rubber compounds

    Energy Technology Data Exchange (ETDEWEB)

    Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

  13. Analysis of the Compounds from the BTEX Group, Emitted During Thermal Decomposition of Alkyd Resin

    Directory of Open Access Journals (Sweden)

    Kubecki M.

    2012-09-01

    Full Text Available Suitability of the given binding agent for the moulding sands preparation depends on the one hand on the estimation of technological properties of the sand and the mould made of it and the obtained casting quality and on the other hand on the assessment of this sand influence on the natural and working environment. Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin (phenol-formaldehyde, urea, furfuryl, urea-furfuryl, alkyd under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene, and also polycyclic aromatic hydrocarbons (PAH can be formed and released.

  14. A Multi-Dimensional Heat Transfer Model of a Tie-Tube and Hexagonal Fuel Element for Nuclear Thermal Propulsion

    Science.gov (United States)

    Gomez, C. F.; Mireles, O. R.; Stewart, E.

    2016-01-01

    The Space Capable Cryogenic Thermal Engine (SCCTE) effort considers a nuclear thermal rocket design based around a Low-Enriched Uranium (LEU) design fission reactor. The reactor core is comprised of bundled hexagonal fuel elements that directly heat hydrogen for expansion in a thrust chamber and hexagonal tie-tubes that house zirconium hydride moderator mass for the purpose of thermalizing fast neutrons resulting from fission events. Created 3D steady state Hex fuel rod model with 1D flow channels. Hand Calculation were used to set up initial conditions for fluid flow. The Hex Fuel rod uses 1D flow paths to model the channels using empirical correlations for heat transfer in a pipe. Created a 2-D axisymmetric transient to steady state model using the CFD turbulent flow and Heat Transfer module in COMSOL. This model was developed to find and understand the hydrogen flow that might effect the thermal gradients axially and at the end of the tie tube where the flow turns and enters an annulus. The Hex fuel rod and Tie tube models were made based on requirements given to us by CSNR and the SCCTE team. The models helped simplify and understand the physics and assumptions. Using pipe correlations reduced the complexity of the 3-D fuel rod model and is numerically more stable and computationally more time-efficient compared to the CFD approach. The 2-D axisymmetric tie tube model can be used as a reference "Virtual test model" for comparing and improving 3-D Models.

  15. Effect of Thermal Cycle on the Formation of Intermetallic Compounds in Laser Welding of Aluminum-Steel Overlap Joints

    Science.gov (United States)

    Fan, J.; Thomy, C.; Vollertsen, F.

    The intermetallic compound (IMC) (or intermetallic phase layer) has a significant influence on the mechanical properties ofjoints between dissimilar metals obtained by thermal processes such as laser welding. Its formation is basically affected by thermal cycles in the joining or contact zone, where the IMC is formed. Within this study, the influence of the thermal cycle on the formation of the IMC during laser welding of an aluminum-steel (Al99.5-DC01) overlap joint was investigated. The temperature was measured directly by a thermocouple, and the weld seam was analyzed by scanning electron microscope (SEM). The influence of peak temperature, cooling time and the integral of the thermal cycle on the thickness of the IMC was identified and discussed. It was identified that cooling time has the biggest influence on the thickness of the IMC.

  16. Comparison of phenolic compounds of orange juice processed by pulsed electric fields (PEF) and conventional thermal pasteurisation.

    Science.gov (United States)

    Agcam, E; Akyıldız, A; Akdemir Evrendilek, G

    2014-01-15

    Processing of orange juice by pulsed electric fields (PEF) and thermal pasteurisation was carried out to compare changes in total phenolic concentration, hydroxybenzoic acid, hydroxycinnamic acids, flavonols, flavones and flavonones before and after being stored at 4°C for 180days. Changes in the initial total phenolic concentration of the samples varied depending on the applied electric field intensity and thermal pasteurisation. Hesperidin and chlorogenic acids were detected as the most abounded flavonoid and phenolic acids in the orange juice, respectively. Except for syringic acid and neoeriocitrin, the concentration of the phenolic compounds indentified in the orange juice samples enhanced after the PEF or thermal pasteurisation. The samples treated with PEF had more stable flavonoids and phenolic acids than those treated with the thermal pasteurisation. The PEF-treated samples had higher sensory scores than the heat-treated samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Partition behavior of virgin olive oil phenolic compounds in oil-brine mixtures during thermal processing for fish canning.

    Science.gov (United States)

    Sacchi, Raffaele; Paduano, Antonello; Fiore, Francesca; Della Medaglia, Dorotea; Ambrosino, Maria Luisa; Medina, Isabel

    2002-05-08

    The chemical modifications and partitioning toward the brine phase (5% salt) of major phenol compounds of extra virgin olive oil (EVOO) were studied in a model system formed by sealed cans filled with oil-brine mixtures (5:1, v/v) simulating canned-in-oil food systems. Filled cans were processed in an industrial plant using two sterilization conditions commonly used during fish canning. The partitioning of phenolic compounds toward brine induced by thermal processing was studied by reversed-phase high-performance liquid chromatographic analysis of the phenol fraction extracted from oils and brine. Hydroxytyrosol (1), tyrosol (2), and the complex phenolic compounds containing 1 and 2 (i.e., the dialdehydic form of decarboxymethyl oleuropein aglycon 3, the dialdehydic form of decarboxymethyl ligstroside aglycon 4, and the oleuropein aglycon 6) decreased in the oily phase after sterilization with a marked partitioning toward the brine phase. The increase of the total amount of 1 and 2 after processing, as well as the presence of elenolic acid 7 released in brine, revealed the hydrolysis of the ester bond of hydrolyzable phenolic compounds 3, 4, and 6 during thermal processing. Both phenomena (partitioning toward the water phase and hydrolysis) contribute to explain the loss of phenolic compounds exhibited by EVOO used as filling medium in canned foods, as well as the protection of n-3 polyunsaturated fatty acids in canned-in-EVOO fish products.

  18. On the thermal decomposition pathway of coordination compounds: synthesis, crystal structures and properties of new polymorphic CuI(2-ethylpyrazine) coordination compounds

    Science.gov (United States)

    Näther, Christian; Jeß, Inke; Lehnert, Nicolai; Hinz-Hübner, Dirk

    2003-10-01

    Five new coordination compounds were prepared at room temperature in solution, under solvothermal conditions at elevated temperatures or by thermal decomposition reactions. In the amine rich 1:2 compound [(CuI) 2(2-ethylpyrazine-N) 4] ( I) discrete molecular complexes are found that consist of (CuI) 2 dimers in which each copper atom is coordinated by two 2-ethylpyrazine ligands. The crystal structure of the 1:1 compound poly[(CuI) 2( μ2-2-ethylpyrazine-N,N') 2] ( II) contains (CuI) 2 dimers which are connected by the 2-ethylpyrazine ligands into layers parallel to (010). The second modification of a 1:1 compound poly[(CuI) 2( μ2-2-ethylpyrazine-N,N')-(2-ethylpyrazine-N)] ( III) consists of 8-membered CuI rings, which are connected by the 2-ethylpyrazine ligands into layers. In one modification of poly[(CuI) 2( μ2-2-ethylpyrazine-N,N')] ( IV) CuI double chains are connected by the ligands into layers parallel to (001). If the preparation is kinetically controlled, crystals of the second modification poly[(CuI) 2( μ2-2-ethylpyrazine)-N,N'

  19. Effect of Boron and Phosphate compounds on Thermal and Fire Properties of wood/HDPE composites

    Science.gov (United States)

    Turgay Akbulut; Nadir Ayrilmis; Turker Dundar; Ali Durmus; Robert H. White; Murat Teker

    2011-01-01

    Melting and non-isothermal crystallization behaviors, oxidative induction time, and fire performance of the injection-molded wood flour-high density polyethylene (HDPE) composites (WPCs) incorporated with different levels (4, 8, or 12 wt %) of boron compounds [borax/boric acid (BX/BA) (0.5:0.5 wt %), zinc borate (ZB)] and phosphorus compounds [mono- and di-ammonium...

  20. Advanced Multiphysics Thermal-Hydraulics Models for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Prashant K [ORNL; Freels, James D [ORNL

    2015-01-01

    Engineering design studies to determine the feasibility of converting the High Flux Isotope Reactor (HFIR) from using highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL). This work is part of an effort sponsored by the US Department of Energy (DOE) Reactor Conversion Program. HFIR is a very high flux pressurized light-water-cooled and moderated flux-trap type research reactor. HFIR s current missions are to support neutron scattering experiments, isotope production, and materials irradiation, including neutron activation analysis. Advanced three-dimensional multiphysics models of HFIR fuel were developed in COMSOL software for safety basis (worst case) operating conditions. Several types of physics including multilayer heat conduction, conjugate heat transfer, turbulent flows (RANS model) and structural mechanics were combined and solved for HFIR s inner and outer fuel elements. Alternate design features of the new LEU fuel were evaluated using these multiphysics models. This work led to a new, preliminary reference LEU design that combines a permanent absorber in the lower unfueled region of all of the fuel plates, a burnable absorber in the inner element side plates, and a relocated and reshaped (but still radially contoured) fuel zone. Preliminary results of estimated thermal safety margins are presented. Fuel design studies and model enhancement continue.

  1. 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.

  2. Development of a QSPR model for predicting thermal stabilities of nitroaromatic compounds taking into account their decomposition mechanisms.

    Science.gov (United States)

    Fayet, Guillaume; Rotureau, Patricia; Joubert, Laurent; Adamo, Carlo

    2011-10-01

    The molecular structures of 77 nitroaromatic compounds have been correlated to their thermal stabilities by combining the quantitative structure-property relationship (QSPR) method with density functional theory (DFT). More than 300 descriptors (constitutional, topological, geometrical and quantum chemical) have been calculated, and multilinear regressions have been performed to find accurate quantitative relationships with experimental heats of decomposition (-ΔH). In particular, this work demonstrates the importance of accounting for chemical mechanisms during the selection of an adequate experimental data set. A reliable QSPR model that presents a strong correlation with experimental data for both the training and the validation molecular sets (R (2) = 0.90 and 0.84, respectively) was developed for non-ortho-substituted nitroaromatic compounds. Moreover, its applicability domain was determined, and the model's predictivity reached 0.86 within this applicability domain. To our knowledge, this work has produced the first QSPR model, developed according to the OECD principles of regulatory acceptability, for predicting the thermal stabilities of energetic compounds.

  3. Spin-glass-like behavior and negative thermal expansion in antiperovskite Mn3Ni1-xCuxN compounds

    Science.gov (United States)

    Ding, Lei; Wang, Cong; Sun, Ying; Colin, Claire V.; Chu, Lihua

    2015-06-01

    The Cu-doping effect on the lattice and magnetic properties in Mn3Ni1-xCuxN (x = 0, 0.3, 0.5, 0.7, 1.0) was extensively investigated. We observed that the Cu-doping at the Ni site complicated the magnetic ground states, which induced the competition of antiferromagnetic and ferromagnetic interactions. Spin-glass-like behavior, arising from possible site-randomness and competing interactions of magnetism, was observed in compounds with x = 0.3, 0.5, and 0.7, and typically discussed by means of the measurement of ac magnetic susceptibility for x = 0.7. The negative thermal expansion (NTE) behavior, due to the magnetic ordering transition, was observed in Mn3Ni1-xCuxN compounds using variable temperature x-ray diffraction. It reveals that the introduction of Cu effectively broadens the temperature range displaying negative thermal expansion. The relationship between the local lattice distortion and the competing magnetic ground states might play an important role in broadening the NTE temperature range in this antiperovskite compound.

  4. Flexible fabrication of biomimetic compound eye array via two-step thermal reflow of simply pre-modeled hierarchic microstructures

    Science.gov (United States)

    Huang, Shengzhou; Li, Mujun; Shen, Lianguan; Qiu, Jinfeng; Zhou, Youquan

    2017-06-01

    A flexible fabrication method for the biomimetic compound eye (BCE) array is proposed. In this method, a triple-layer sandwich-like coating configuration was introduced, and the required hierarchic microstructures are formed with a simple single-scan exposure in maskless digital lithography. Taking advantage of the difference of glass transition point (Tg) between photoresists of each layer, the pre-formed hierarchic microstructures are in turn reflowed to the curved substrate and the BCE ommatidia in a two-step thermal reflow process. To avoid affecting the spherical substrate formed in the first thermal reflow, a non-contact strategy was proposed in the second reflow process. The measurement results were in good agreement with the designed BCE profiles. Results also showed that the fabricated BCE had good performances in optical test. The presented method is flexible, convenient, low-cost and can easily adapt to the fabrications of other optical elements with hierarchic microstructures.

  5. The Molecular Structure of SBR and Filler Type Effects on Thermal Diffusivity of SBR/BR Compounds Used in Tire Tread

    Directory of Open Access Journals (Sweden)

    Mir Hamid Reza Ghoreishy

    2017-05-01

    Full Text Available This research work is devoted to the study of the thermal diffusivity of SBR/BR compounds used as the tread of radial tires. Three series of rubber compounds were prepared, in which two solution SBR grades (with and without extra oil as well as an emulsion SBR were selected. Five compounds with different CB/silica ratios were designed for each of the three series. Moreover, three compounds without fillers were prepared as reference samples. Thermal diffusivities of the compounds were determined by a novel technique to solve an inverse heat transfer problem. Abaqus and Isight codes were used to carry out the finite element solution and optimization. It is shown that, in all the compounds the thermal diffusivities were reduced with increasing the temperature. In addition, the macro- and micro- structures of SBR as well as the CB/silica ratios greatly affected the variations in thermal diffusivities with temperature. The thermal diffusivity and its variabilities were studied and discussed by different structural and functional parameters such as intermolecular distance, molecular vibrational energy, difference between the thermal diffusivities of the polymer and filler, and the chemical bonds between the polymer and silica.

  6. Multidimensional gas chromatography using microfluidic switching and low thermal mass gas chromatography for the characterization of targeted volatile organic compounds.

    Science.gov (United States)

    Luong, J; Gras, R; Hawryluk, M; Shellie, R A; Cortes, H J

    2013-05-03

    Volatile organic compounds such as light hydrocarbons, dienes, and aromatic compounds are often encountered in the manufacturing and processing environments of chemical and petrochemical segments. These compounds need to be closely monitored for process optimization, plant maintenance and industrial hygiene purposes. A high throughput analytical approach has been successfully developed and implemented for the accurate measurement of fourteen commonly encountered analytes. The approach incorporates a recently introduced 5-port planar microfluidic device configured for use as a Deans switch for multidimensional gas chromatography. The use of multidimensional gas chromatography allows the elimination of potential chromatographic contaminants with a substantial enhancement of stationary phase selectivity via the use of columns with different separation mechanisms, and the back-flushing of heavier undesired hydrocarbons. A low thermal mass gas chromatographic module was employed in the second dimension of the two-dimensional gas chromatography system and was used to provide independent temperature control, and rapid heating and cooling to meet the high throughput requirements. By successfully combining these concepts, complete analysis of fourteen targeted components can be conducted in less than 120s. Repeatability of retention times for all compounds was found to be less than 0.05% (n=20). Repeatability of area counts at two levels, namely 10ppmv and 1000ppmv over a period of two days was found to be less than 3% (n=20). Apart from methane, which has a detection limit of 0.4ppmv, the rest of the compounds were found to have detection limits of less than 0.2ppmv. Compounds of interest were found to be linear over a range of 500ppbv-3000ppmv with correlation coefficients greater than 0.999. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Changes in guava (Psidium guajava L. var. Paluma nectar volatile compounds concentration due to thermal processing and storage

    Directory of Open Access Journals (Sweden)

    Maria Ivaneide Coutinho Correa

    2010-12-01

    Full Text Available Guava nectars were formulated for approximately 10, 12, or 14 ºBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 ºC/42 seconds in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 ºC or refrigerated (5 ± 2 ºC under fluorescent light exposure and analyzed on the day after processing (time zero and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC -Mass Spectrometry (MS: hexanal, (E-hex-2-enal, 1-hexenol, (Z-hex-3-enol, (Z-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001 in hexanal and (Z-hex-3-enyl acetate (p = 0.0029. As for the storage time, there was a much greater decrease in the esters contents, such as (Z-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

  8. Determination of Volatile Organic Compounds in Fourty Five Salvia Species by Thermal Desorption-GC-MS Technique

    Directory of Open Access Journals (Sweden)

    Seda Damla Hatipoglu

    2016-05-01

    Full Text Available Volatile organic compounds (VOC from dried aerial parts (flowers, leafs, leafy branches and stems of fourty five Salvia species, harvested from different regions of Turkey, were determined using thermal desorption technique coupled to gas chromatography-mass spectrometer (TD-GC-MS. Total percentages of the detected volatile organic compounds of the Salvia species ranged from 70.30 to 99.65% . Total yield of VOC was found to be highly variable among Salvia species, and the percentage of each component also exhibited high variation. While sesquiterpene hydrocarbons represented 0.90-45.02% of the volatile organic compounds, the others were found to be monoterpene hydrocarbons 0.00-32.25%, monoterpenoids 0.94- 53.60%, sesquiterpenoids 0.00- 31.45% and hydrocarbons and derivatives 2.99-46.87%. The rest of the composition consisted of diterpene alcohols, fatty acids, phenolics and triterpenes. In total, 108 volatile compounds were identified from studied 45 Anatolian Salvia species.

  9. Laser-induced thermal coagulation enhances skin uptake of topically applied compounds

    DEFF Research Database (Denmark)

    Haak, C S; Hannibal, J; Paasch, U

    2017-01-01

    BACKGROUND: Ablative fractional laser (AFL) generates microchannels in skin surrounded by a zone of thermally altered tissue, termed the coagulation zone (CZ). The thickness of CZ varies according to applied wavelength and laser settings. It is well-known that AFL channels facilitate uptake...

  10. Structural, thermal and electrical studies of a novel rubidium phosphite tellurate compound

    DEFF Research Database (Denmark)

    Beyribey, Didem Berceste; Hallinder, Jonathan

    2012-01-01

    Structural, thermal and electrical properties studies of rubidium phosphite tellurate, RbH(PO3H)·Te(OH)6, were performed. An endothermic peak, which reached a completion at about 315 °C accompanied with a weight loss of 4.6 wt.%, was attributed to dehydration. Four types of pellets were produced...

  11. Gas chromatographic-mass spectrometric analysis of some potential toxicants amongst volatile compounds emitted during large-scale thermal degradation of poly(acrylonitrile-butadiene-styrene) plastic.

    Science.gov (United States)

    Shapi, M M; Hesso, A

    1991-01-02

    A number of compounds emitted during the thermal degradation of plastics are potentially toxic. This study was aimed at identifying the volatile compounds emitted during large-scale thermal degradation of poly(acrylonitrile-butadiene-styrene). About 5 g of the sample were degraded at between 25 and 470 degrees C in air and nitrogen in a device that can simulate temperature-programmed thermogravimetry. The volatiles were collected in dichloromethane using the solvent trap technique. Some of the 92 compounds identified by gas chromatography-mass spectrometry were found to have no hitherto documented toxicological profiles, even though they are potentially dangerous.

  12. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds

    Directory of Open Access Journals (Sweden)

    Nigel V. Gale

    2016-08-01

    Full Text Available Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME–gas chromatography–mass spectrometry (GC-MS to qualitatively describe organic compounds in both biochar (through headspace extraction, and in the water leachates (through direct injection. Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species

  13. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Thermal analytic model of current gain for bipolar junction transistor-bipolar static induction transistor compound device

    Science.gov (United States)

    Zhang, You-Run; Zhang, Bo; Li, Ze-Hong; Lai, Chang-Jin; Li, Zhao-Ji

    2009-02-01

    This paper proposes a thermal analytical model of current gain for bipolar junction transistor-bipolar static induction transistor (BJT-BSIT) compound device in the low current operation. It also proposes a best thermal compensating factor to the compound device that indicates the relationship between the thermal variation rate of current gain and device structure. This is important for the design of compound device to be optimized. Finally, the analytical model is found to be in good agreement with numerical simulation and experimental results. The test results demonstrate that thermal variation rate of current gain is below 10% in 25 °C-85°C and 20% in -55°C-25°C.

  14. Thermal evolution of the Ni{sub 3}Fe compound obtained by mechanical alloying as probed by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Popa, F. [Department of Materials Science and Engineering, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Isnard, O. [Institut Néel, CNRS, associé à l’Université de Grenoble J. Fourier, 25 rue des Martyrs, BP 166, 38042 Grenoble (France); Chicinaş, I., E-mail: Ionel.Chicinas@stm.utcluj.ro [Department of Materials Science and Engineering, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Pop, V. [Faculty of Physics, Babes-Bolyai University, 1 M. Kogălniceanu St., 400084 Cluj-Napoca (Romania)

    2013-03-25

    Highlights: ► Thermal evolution of Ni{sub 3}Fe compound obtained by MA was studied by DSC. ► At low milling times both Ni{sub 3}Fe formation and recrystallization occur during heating. ► Ni{sub 3}Fe grains obtained by milling and Ni{sub 3}Fe new germs produced during heating growth. ► Ni{sub 3}Fe compound recrystallization enthalpy increases by increasing milling time. ► The activation energy of the recrystallization process has been calculated. -- Abstract: An investigation of the formation of Ni{sub 3}Fe soft magnetic material by high energy ball milling combining X-ray as well as neutron diffraction and differential scanning calorimetry (DSC) is presented. The Ni{sub 3}Fe powders have been obtained by mechanical alloying of elemental powders in a planetary mill under argon atmosphere for milling times ranging from 2 h to 28 h. Ni{sub 3}Fe intermetallic compound is obtained after 10–12 h of milling, as showed by X-ray and neutron diffraction and magnetic studies. The obtained crystallite has the mean size of 20 ± 2 nm after 28 h of milling. The DSC curves, recorded for different heating speeds, present a broad transformation reaction of the as-milled powders. The onset temperature of the transition is about 500 °C. The transition has been assigned to the re-crystallization of the nanocrystalline samples. The Curie temperature of Ni{sub 3}Fe is also observed in the DSC curves, indicating the compound formation. DSC studies prove that the activation energy and the re-crystallization enthalpy increase with the milling time, as the compound is formed by milling and his grain size decrease.

  15. Rapid characterization of chemical compounds in liquid and solid states using thermal desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Huang, Min-Zong; Zhou, Chi-Chang; Liu, De-Lin; Jhang, Siou-Sian; Cheng, Sy-Chyi; Shiea, Jentaie

    2013-10-01

    Rapid characterization of thermally stable chemical compounds in solid or liquid states is achieved through thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS). A feature of this technique is that sampling, desorption, ionization, and mass spectrometric detection are four separate events with respect to time and location. A metal probe was used to sample analytes in their solid or liquid states. The probe was then inserted in a preheated oven to thermally desorb the analytes on the probe. The desorbed analytes were carried by a nitrogen gas stream into an ESI plume, where analyte ions were formed via interactions with charged solvent species generated in the ESI plume. The analyte ions were subsequently detected by a mass analyzer attached to the TD-ESI source. Quantification of acetaminophen in aqueous solutions using TD-ESI/MS was also performed in which a linear response for acetaminophen was obtained between 25 and 500 ppb (R(2) = 0.9978). The standard deviation for a reproducibility test for ten liquid samples was 9.6%. Since sample preparation for TD-ESI/MS is unnecessary, a typical analysis can be completed in less than 10 s. Analytes such as the active ingredients in over-the-counter drugs were rapidly characterized regardless of the different physical properties of said drugs, which included liquid eye drops, viscous cold syrup solution, ointment cream, and a drug tablet. This approach was also used to detect trace chemical compounds in illicit drugs and explosives, in which samples were obtained from the surfaces of a cell phone, piece of luggage made from hard plastic, business card, and wooden desk.

  16. 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.

  17. Clathrate Hydrates for Thermal Energy Storage in Buildings: Overview of Proper Hydrate-Forming Compounds

    Directory of Open Access Journals (Sweden)

    Beatrice Castellani

    2014-09-01

    Full Text Available Increasing energy costs are at the origin of the great progress in the field of phase change materials (PCMs. The present work aims at studying the application of clathrate hydrates as PCMs in buildings. Clathrate hydrates are crystalline structures in which guest molecules are enclosed in the crystal lattice of water molecules. Clathrate hydrates can form also at ambient pressure and present a high latent heat, and for this reason, they are good candidates for being used as PCMs. The parameter that makes a PCM suitable to be used in buildings is, first of all, a melting temperature at about 25 °C. The paper provides an overview of groups of clathrate hydrates, whose physical and chemical characteristics could meet the requirements needed for their application in buildings. Simulations with a dynamic building simulation tool are carried out to evaluate the performance of clathrate hydrates in enhancing thermal comfort through the moderation of summer temperature swings and, therefore, in reducing energy consumption. Simulations suggest that clathrate hydrates have a potential in terms of improvement of indoor thermal comfort and a reduction of energy consumption for cooling. Cooling effects of 0.5 °C and reduced overheating hours of up to 1.1% are predicted.

  18. Hydrolytic and thermal degradation of PCL and PCL/Bentonite compounds

    Energy Technology Data Exchange (ETDEWEB)

    Franca, Danyelle Campos; Bezerra, Elieber Barros; Morais, Dayanne Diniz de Souza; Araujo, Edcleide Maria [Universidade Federal de Campina grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Wellen, Renate Maria Ramos, E-mail: wellen.renate@gmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Engenharia de Materiais

    2016-05-15

    Poly(ε-caprolactone)/montmorillonite (PCL/MMT) and Poly(εcaprolactone)/organo-modified montmorillonite (PCL/OMMT) compounds at 3% w/w clay content were prepared by melting mixing. The effect of MMT and OMMT on the degradability of PCL injected specimens was investigated in vacuum at 40 deg C for up to 45 days and in aqueous medium at 40 deg C for up to 45 days. Selected specimens were collected after 15, 30 and 45 days of exposure. Microstructural changes were monitored during the degradation experiment by means of melt flow rate (MFR), weight loss, X ray diffraction (XRD), mechanical properties, and scanning electron microscopy (SEM). PCL and its compounds revealed not to be prone to hydrolytic degradation with similar results for MFR of samples exposed in vacuum and water. Gain and loss of weight were observed during experiments, probably due to swelling mechanism taking place in two stages, with the amorphous phase being the first to be swelled followed by the crystalline one. By XRD a new peak corresponding to (002) plane was evident for PCL/OMMT. PCL proved to be resistant to degradation since experiments carried out in vacuum or in aqueous medium for up to 45 days were not enough to affect the mechanical integrity of PCL samples. (author)

  19. Measurement of phonon dispersion relation in negative thermal expansion compound ZrW2O8

    Science.gov (United States)

    Mittal, R.; Chaplot, S. L.; Pintschovius, L.; Achary, S. N.; Kowach, G. R.

    2007-12-01

    Isotropic negative thermal expansion (NTE) is found in cubic AX2O8(A = Zr, Hf: X=W, Mo) up to high temperatures (1050 K). Anharmonicity of low energy phonon modes plays an important role in leading to the NTE behaviour. Earlier we verified our predictions of large phonon softening for low energy phonons (below 8 meV) through high-pressure inelastic neutron scattering measurements on powder samples at ILL, France. Now we have measured the phonon dispersion relation from a single crystal of ZrW2O8. The measurements are useful to verify our prediction of highly anharmonic nature of specific phonon branches, in particular the transverse acoustic branch, and other branches up to 10 meV. These modes below 10 meV mainly contribute to the NTE in ZrW2O8.

  20. Thermal Stability and Coefficient of Friction of the Diamond Composites with the Titanium Compound Bonding Phase

    Science.gov (United States)

    Cygan, S.; Jaworska, L.; Putyra, P.; Ratuszek, W.; Cyboron, J.; Klimczyk, P.

    2017-05-01

    In this paper, processes occurring during heat treatment of the diamond-Ti compound composites without Co addition were investigated and compared with commercial PCD. Three types of materials were prepared. The first material was sintered using the mixture containing diamond and 10 mass% of TiC, the second material was prepared using diamond powder and 10 mass% of Ti-Si-C, and the third composite was sintered using the addition of 10 mass% of TiB2. During the research, it was proved that TiO2 formation contributes to material swelling and WO3 (W is present from the milling process) causes a significant increase in coefficient of friction. TiC and Ti-Si-C bonded materials are very susceptible to this process of oxidation; their hardness drops absolutely after wear test at 600 °C. The diamond composite with TiB2 is the most resistant to oxidation from investigated materials.

  1. Thermodynamic study on six tricyclic nitrogen heterocyclic compounds by thermal analysis and effusion techniques

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, Bruno [Istituto per lo Studio dei Materiali Nanostrutturati, Consiglio Nazionale delle Ricerche, Dipartimento di Chimica, Sapienza Università di Roma, P .le A. Moro 5, I-00185 Rome (Italy); Lapi, Andrea [Dipartimento di Chimica, Sapienza Università di Roma, and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, Dipartimento di Chimica, Sapienza Università di Roma, P. le A. Moro 5, I-00185 Rome (Italy); Vecchio Ciprioti, Stefano, E-mail: stefano.vecchio@uniroma1.it [Dipartimento S.B.A.I., Sapienza Università di Roma, Via del Castro Laurenziano 7, I-00161 Rome (Italy)

    2016-07-20

    Highlights: • Melting characteristics of tricyclic N-hetero tricyclic compounds were measured by DSC. • Vapor pressures of solid and liquid compounds were measured by effusion and iso-TG. • Thermochemical data from solid and liquid phases were compared with literature. • Good agreement between experimental and literature data with only few exceptions. - Abstract: The molar sublimation and vaporization enthalpies of acridine, phenanthridine, 1,7-phenanthroline, 1,10-phenanthroline, 4,7-phenanthroline and phenazine were determined at the averages of their respective experimental temperature ranges (Δ{sub cr}{sup g}H{sup 0}{sub m} () and Δ{sub l}{sup g}H{sup 0}{sub m} (), respectively) from the temperature dependencies of vapor pressure determined using Knudsen Effusion Mass Loss (KEML), Torsion Effusion (TE) and Isothermal Thermogravimetry (ITG) above their solid and liquid phases. The fusion characteristics (melting temperatures and the molar standard enthalpies of fusion at their melting temperatures) measured by Differential Scanning Calorimetry (DSC) were compared with the available literature values. Solid and liquid vapor pressure data determined by KEML, TE and ITG techniques as well as Δ{sub cr}{sup g}H{sup 0}{sub m} () and Δ{sub l}{sup g}H{sup 0}{sub m} () values, adjusted at 298.15 K by using the values of C{sub p}(cr) and C{sub p}(l) calculated by a well-known group additivity method, were found to be fairly correlated and are consistent with the available literature data. Final Δ{sub cr}{sup g}H{sup 0}{sub m}(298.15 K) values were also provided as weighted averages of all the available data.

  2. Formation of polymerization compounds during thermal oxidation of cottonseed oil, partially hydrogenated cottonseed oil and their blends

    Directory of Open Access Journals (Sweden)

    Barrera-Arellano, D. Laboratório de Óleos e Gorduras, Departa

    2006-09-01

    Full Text Available Samples of cottonseed oil, partially hydrogenated cottonseed oil and their blends, with iodine values between 60 and 110, tocopherol-stripped or not by aluminium oxide treatment, were submitted to thermal oxidation, at 180 °C, for 10 hours. Samples were collected at 0, 2, 5, 8 and 10 hours, for the determination of dimers and polymers (degradation compounds and of tocopherols. The influence of the degree of hydrogenation on the formation of dimers and polymers and the role of originally present tocopherols in the protection of fats and oils against thermal degradation was verified. The degradation curves for tocopherols showed a fast destruction rate for the tocopherols present in cottonseed fats and oil (α and γ-tocopherols, with residual levels close to zero after 10 hours under thermal oxidation conditions. Nevertheless, samples with their natural tocopherols presented a slower rate of thermal degradation. The unsaturation degree was apparently more important in the protection against thermal degradation than the content of tocopherolsMuestras de aceite de algodón, aceite de algodón parcialmente hidrogenado y sus mezclas, con índices de yodo de 60 a 110, tratadas o no con óxido de aluminio, fueron sometidas a termoxidación, a 180 °C, durante 10 horas. Se retiraron muestras en los tiempos 0, 2, 5, 8 y 10 horas, para determinación de dímeros y polímeros (compuestos de degradación y de tocoferoles. Se verificó la influencia del grado de hidrogenación sobre la formación de dímeros y polímeros, y también el papel de los tocoferoles originalmente presentes en el aceite y en las grasas, en la protección contra la degradación térmica. Las curvas de degradación de los tocoferoles mostraron una destrucción bastante rápida de los tocoferoles presentes en el aceite y en las grasas de algodón (α y γ-tocoferoles, con niveles residuales próximos a cero después de 10 horas de termoxidación. Aún así, muestras con sus

  3. Testing and linearity calibration of films of phenol compounds exposed to thermal neutron field for EPR dosimetry.

    Science.gov (United States)

    Gallo, S; Panzeca, S; Longo, A; Altieri, S; Bentivoglio, A; Dondi, D; Marconi, R P; Protti, N; Zeffiro, A; Marrale, M

    2015-12-01

    This paper reports the preliminary results obtained by Electron Paramagnetic Resonance (EPR) measurements on films of IRGANOX® 1076 phenols with and without low content (5% by weight) of gadolinium oxide (Gd2O3) exposed in the thermal column of the Triga Mark II reactor of LENA (Laboratorio Energia Nucleare Applicata) of Pavia (Italy). Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The dependence of EPR signal as function of neutron dose was investigated in the fluence range between 10(11) cm(-2) and 10(14) cm(-2). Linearity of EPR response was found and the signal was compared with that of commercial alanine films. Our analysis showed that gadolinium oxide (5% by weight) can enhance the thermal neutron sensitivity more than 18 times. Irradiated dosimetric films of phenolic compound exhibited EPR signal fading of about 4% after 10 days from irradiation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Outdoor Performance Analysis of a Photovoltaic Thermal (PVT Collector with Jet Impingement and Compound Parabolic Concentrator (CPC

    Directory of Open Access Journals (Sweden)

    Ahed Hameed Jaaz

    2017-08-01

    Full Text Available This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT collector and compound parabolic concentrators (CPC on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m2 and an ambient temperature of 33.5 °C. It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV module at 1:30 p.m. The short-circuit current ISC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC.

  5. Outdoor Performance Analysis of a Photovoltaic Thermal (PVT) Collector with Jet Impingement and Compound Parabolic Concentrator (CPC).

    Science.gov (United States)

    Jaaz, Ahed Hameed; Hasan, Husam Abdulrasool; Sopian, Kamaruzzaman; Kadhum, Abdul Amir H; Gaaz, Tayser Sumer; Al-Amiery, Ahmed A

    2017-08-01

    This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT) collector and compound parabolic concentrators (CPC) on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m² and an ambient temperature of 33.5 °C). It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV) module at 1:30 p.m. The short-circuit current I SC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC.

  6. Outdoor Performance Analysis of a Photovoltaic Thermal (PVT) Collector with Jet Impingement and Compound Parabolic Concentrator (CPC)

    Science.gov (United States)

    Jaaz, Ahed Hameed; Hasan, Husam Abdulrasool; Sopian, Kamaruzzaman; Kadhum, Abdul Amir H.; Gaaz, Tayser Sumer

    2017-01-01

    This paper discusses the effect of jet impingement of water on a photovoltaic thermal (PVT) collector and compound parabolic concentrators (CPC) on electrical efficiency, thermal efficiency and power production of a PVT system. A prototype of a PVT solar water collector installed with a jet impingement and CPC has been designed, fabricated and experimentally investigated. The efficiency of the system can be improved by using jet impingement of water to decrease the temperature of the solar cells. The electrical efficiency and power output are directly correlated with the mass flow rate. The results show that electrical efficiency was improved by 7% when using CPC and jet impingement cooling in a PVT solar collector at 1:00 p.m. (solar irradiance of 1050 W/m2 and an ambient temperature of 33.5 °C). It can also be seen that the power output improved by 36% when using jet impingement cooling with CPC, and 20% without CPC in the photovoltaic (PV) module at 1:30 p.m. The short-circuit current ISC of the PV module experienced an improvement of ~28% when using jet impingement cooling with CPC, and 11.7% without CPC. The output of the PV module was enhanced by 31% when using jet impingement cooling with CPC, and 16% without CPC. PMID:28763048

  7. Synthesis of boron nitride nanostructures from catalyst of iron compounds via thermal chemical vapor deposition technique

    Science.gov (United States)

    da Silva, Wellington M.; Ribeiro, Hélio; Ferreira, Tiago H.; Ladeira, Luiz O.; Sousa, Edésia M. B.

    2017-05-01

    For the first time, patterned growth of boron nitride nanostructures (BNNs) is achieved by thermal chemical vapor deposition (TCVD) technique at 1150 °C using a mixture of FeS/Fe2O3 catalyst supported in alumina nanostructured, boron amorphous and ammonia (NH3) as reagent gas. This innovative catalyst was synthesized in our laboratory and systematically characterized. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The X-ray diffraction profile of the synthesized catalyst indicates the coexistence of three different crystal structures showing the presence of a cubic structure of iron oxide and iron sulfide besides the gamma alumina (γ) phase. The results show that boron nitride bamboo-like nanotubes (BNNTs) and hexagonal boron nitride (h-BN) nanosheets were successfully synthesized. Furthermore, the important contribution of this work is the manufacture of BNNs from FeS/Fe2O3 mixture.

  8. Fabrication and thermal characterization of amorphous and nanocrystalline Al{sub 9}FeNi/Al{sub 3}Ti compound

    Energy Technology Data Exchange (ETDEWEB)

    Tavoosi, Majid, E-mail: ma.tavoosi@gmail.com

    2017-01-15

    In this study, the fabrication and structural characterization of amorphous/nanocrystalline Al{sub 9}FeNi/Al{sub 3}Ti phase has been performed. In this regards, milling and annealing processes were applied on Al{sub 80}Fe{sub 10}Ti{sub 5}Ni{sub 5} (at. %) powder mixture for different periods of time. The prepared samples were characterized using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM) and differential scanning calorimetery (DSC). According to the results, supersaturated solid solution, nanocrystalline Al{sub 9}FeNi/Al{sub 3}Ti (with average crystallite size of about 7 nm) and amorphous phases indicated three different microstructures which can be formed in Al{sub 80}Fe{sub 10}Ti{sub 5}Ni{sub 5} system during milling process. The formed supersaturated solid solution and amorphous phases were unstable and transformed to Al{sub 9}FeNi/Al{sub 3}Ti intermetallic compound during annealing process. It is shown that, Al{sub 9}FeNi phase in Al{sub 9}FeNi/Al{sub 3}Ti intermetallic compound can decompose into Al{sub 3}Ni, Al{sub 13}Fe{sub 4} and liquid phases during a reversible peritectic reaction at 809 °C. - Highlights: • We study the effect of milling process on Al{sub 80}Fe{sub 10}Ti{sub 5}Ni{sub 5} alloy. • We study the effect of annealing on Al{sub 80}Fe{sub 10}Ti{sub 5}Ni{sub 5} supersaturated solid solution phase. • We study the effect of annealing on Al{sub 80}Fe{sub 10}Ti{sub 5}Ni{sub 5} amorphous phase. • We study the thermal behaviour of Al{sub 9}FeNi/Al{sub 3}Ti compound.

  9. The STAT7 Code for Statistical Propagation of Uncertainties In Steady-State Thermal Hydraulics Analysis of Plate-Fueled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Floyd E. [Argonne National Lab. (ANL), Argonne, IL (United States); Hu, Lin-wen [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Nuclear Reactor Lab.; Wilson, Erik [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-12-01

    The STAT code was written to automate many of the steady-state thermal hydraulic safety calculations for the MIT research reactor, both for conversion of the reactor from high enrichment uranium fuel to low enrichment uranium fuel and for future fuel re-loads after the conversion. A Monte-Carlo statistical propagation approach is used to treat uncertainties in important parameters in the analysis. These safety calculations are ultimately intended to protect against high fuel plate temperatures due to critical heat flux or departure from nucleate boiling or onset of flow instability; but additional margin is obtained by basing the limiting safety settings on avoiding onset of nucleate boiling. STAT7 can simultaneously analyze all of the axial nodes of all of the fuel plates and all of the coolant channels for one stripe of a fuel element. The stripes run the length of the fuel, from the bottom to the top. Power splits are calculated for each axial node of each plate to determine how much of the power goes out each face of the plate. By running STAT7 multiple times, full core analysis has been performed by analyzing the margin to ONB for each axial node of each stripe of each plate of each element in the core.

  10. Influence of the aromatic substitutes in the thermal and kinetic behavior of mesoionic compounds of the 1,3-thiazole-5-tiolate system

    Energy Technology Data Exchange (ETDEWEB)

    Alves de Morais, Soraya, E-mail: sorayaamorais@yahoo.com.b [Universidade Estadual da Paraiba, Departamento de Quimica, Av. Baraunas, s/n, Campina Grande, PB (Brazil); Rogrigues da Silva Morais, Crislene, E-mail: crislene@pq.cnpq.b [Universidade Federal de Campina Grande, Unidade Academica de Engenharia de Materiais, Av. Aprigio Veloso, 882, Campina Grande, PB (Brazil); Filgueiras de Athayde Filho, Petronio, E-mail: athayde-filho@pq.cnpq.b [Universidade Federal da Paraiba, Departamento de Quimica - CCEN, 58.081-970, Joao Pessoa, PB (Brazil); Freitas Lira, Bruno, E-mail: brunofrlira@hotmail.co [Universidade Federal da Paraiba, Departamento de Quimica - CCEN, 58.081-970, Joao Pessoa, PB (Brazil); Feitosa de Souza, Marcos Antonio, E-mail: ramcos31@yahoo.com.b [Universidade Federal da Paraiba, Departamento de Quimica - CCEN, 58.081-970, Joao Pessoa, PB (Brazil)

    2010-04-16

    In this work, three mesoionic compounds of the 1,3-thiazole-5-tiolat system were studied, derived from amino acids of the glycerin through 1,3-dipolar cyclo-addition/reversion reaction. The mesoionic compounds were characterized as: MI-1 (mesoionic 2-(4-chlorophenyl)-3-methyl-4-phenyl-1,3-thiazole-5-tiolat); MI-2 (mesoionic 2-(4-chlorophenyl)-3-methyl-4-(4-isopropylphenyl)-1,3-thiazole-5-tiolat) and MI-3 (Mesoionic 2-(4-clorophenyl)-3-methyl-4-(methoxyphenyl)-1,3-thiazole-5-tiolate). These compounds were characterized by infrared spectroscopy (IR), nuclear magnetic resonance (NMR), thermogravimetry (TG) and differential scanning calorimeter (DSC). Also, the kinetic study of the thermal decomposition by non-isothermal thermogravimetry has been realized, presenting, the kinetic and thermal behavior of these compounds. The results of the spectroscopic analysis confirmed the structure of the synthesized mesoionic compounds. The DSC curves of the mesoionic compounds MI-1, MI-2, and MI-3 indicated the fusion of two of them followed by a subsequent decomposition. The TG/DTG curves showed that the decomposition of the mesoionic compounds MI-1, MI-2 and MI-3 occurred in several steps.

  11. Thermal and spectroscopic study to investigate p-aminobenzoic acid, sodium p-aminobenzoate and its compounds with some lighter trivalent lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, J.A.; Nunes, W.D.G.; Colman, T.A.D.; Nascimento, A.L.C.S do [Instituto de Química, UNESP—Universidade Estadual Paulista, Campus Araraquara, Departamento de Química Analítica, Araraquara 14801-970, SP (Brazil); Caires, F.J. [Faculdade de Ciências, UNESP—Universidade Estadual Paulista, Campus Bauru, Departamento de Química, Bauru 17033-260, SP (Brazil); Campos, F.X. [Instituto de Química, UNESP—Universidade Estadual Paulista, Campus Araraquara, Departamento de Química Analítica, Araraquara 14801-970, SP (Brazil); Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso, Primavera do Leste 78850-000, MT (Brazil); Gálico, D.A. [Instituto de Química, UNICAMP—Universidade Estadual de Campinas, Campinas 13083-970, SP (Brazil); Ionashiro, M., E-mail: massaoi@yahoo.com.br [Instituto de Química, UNESP—Universidade Estadual Paulista, Campus Araraquara, Departamento de Química Analítica, Araraquara 14801-970, SP (Brazil)

    2016-01-20

    Highlights: • The p-aminobenzoic acid melts followed partial evaporation. • The stoichiometry of compounds was established by TG, EA and complexometry. • The TG–DTA curves provided previously unreported information about thermal behavior. - Abstract: The characterization, thermal stability and thermal decomposition of some lighter trivalent lanthanide p-aminobenzoates, Ln(C{sub 7}H{sub 6}NO{sub 2}){sub 3}·H{sub 2}O (Ln = La, Ce, Pr, Nd, Sm), as well as the thermal behavior and spectroscopic study of p-aminobenzoic acid C{sub 7}H{sub 7}NO{sub 2} and its sodium salt were investigated. The following methods were utilized: simultaneous thermogravimetry and differential thermal analysis (TG–DTA) in dynamic dry air and nitrogen atmospheres; differential scanning calorimetry (DSC); middle (MIR) and near (NIR) infrared region spectroscopy; evolved gas analysis (EGA); elemental analysis; complexometry; X-ray diffraction (XRD); and diffuse reflectance spectroscopy (DR) in the ultraviolet and visible regions. All the compounds were obtained monohydrated and the thermal decomposition occurred in two, three or four steps in an air atmosphere, and three or four steps in N{sub 2} atmosphere. In both atmospheres (air and N{sub 2}) the final residues were CeO{sub 2}, Pr{sub 6}O{sub 11}, Ln{sub 2}O{sub 3} (Ln = La, Nd, Sm). The results also provided information concerning the coordination mode and thermal behavior, as well as the identification of the gaseous products which evolved during the thermal decomposition of these compounds. The DR and NIR spectra provided information about the ligand absorption bands and the f–f transitions of the Nd{sup 3+}, Pr{sup 3+} and Sm{sup 3+} ions.

  12. Dataset on the electronic and thermal transport properties of quaternary compounds of (PbTe0.95−x(PbSex(PbS0.05

    Directory of Open Access Journals (Sweden)

    Dianta Ginting

    2017-08-01

    Full Text Available The data presented in this article are related to the research article entitled “High thermoelectric performance in pseudo quaternary compounds of (PbTe0.95−x(PbSex(PbS0.05 by simultaneous band convergence and nano precipitation” (Ginting et al., 2017 [1]. We measured electrical and thermal transport properties such as temperature-dependent Hall carrier density nH, Hall mobility μH, thermal diffusivity D, heat capacity Cp, and power factor S2σ in (PbTe0.95−x(PbSex(PbS0.05 (x=0.0, 0.05, 0.10, 0.15, 0.20, 0.35, and 0.95 compounds with other related compounds from references. From the theoretical fitting of thermal conductivity κ, we found that the temperature-dependent thermal conductivity follows nano-structure model as well as alloy scattering. Transmission electron microscopy images shows that there are numerous nano-scale precipitates in a matrix. Owing to the low thermal conductivity and high power factor, we report high thermoelectric performances such as the high ZT, engineering ZTeng, efficiency η.

  13. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn-Ag-Cu/Cu solder joint during different thermal conditions.

    Science.gov (United States)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-06-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn-Ag-Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided.

  14. Pyrolysis reaction networks for lignin model compounds: unraveling thermal deconstruction of β-O-4 and α-O-4 compounds

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong S.; Singh, Rahul; Zhang, Jing; Balasubramanian, Ganesh; Sturgeon, Matthew R.; Katahira, Rui; Chupka, Gina; Beckham, Gregg T.; Shanks, Brent H.

    2016-01-01

    Although lignin is one of the main components of biomass, its pyrolysis chemistry is not well understood due to complex heterogeneity. To gain insights into this chemistry, the pyrolysis of seven lignin model compounds (five ..beta..-O-4 and two ..alpha..-O-4 linked molecules) was investigated in a micropyrolyzer connected to GC-MS/FID. According to quantitative product mole balance for the reaction networks, concerted retro-ene fragmentation and homolytic dissociation were strongly suggested as the initial reaction step for ..beta..-O-4 compounds and ..alpha..-O-4 compounds, respectively. The difference in reaction pathway between compounds with different linkages was believed to result from thermodynamics of the radical initiation. The rate constants for the different reaction pathways were predicted from ab initio density functional theory calculations and pre-exponential literature values. The computational findings were consistent with the experiment results, further supporting the different pyrolysis mechanisms for the ..beta..-ether linked and ..alpha..-ether linked compounds. A combination of the two pathways from the dimeric model compounds was able to describe qualitatively the pyrolysis of a trimeric lignin model compound containing both ..beta..-O-4 and ..alpha..-O-4 linkages.

  15. Core Thermal-Hydraulic Design of a Sodium Cooled Fast Reactor for the U/TRU Fuel Modification

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sun Rock; Cho, Chung Ho; Kim, Young Gyun; Song, Hoon; Park, Won Seok; Kim, Sang Ji [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    The Korea Atomic energy Research Institute (KAERI) has been developing an advanced SFR design technology with the final goal of constructing a demonstration plant by 2028. The main objective of the SFR demonstration plant is to verify TRU metal fuel performance, large-scale reactor operation, and transmutation ability of high-level wastes. However, in the early stage, the SFR will run on low enriched uranium fuel due to a lack of TRU fuel qualification. After sequential evaluations of the fuel performance, the fissile fuel material will transform from uranium to LTRU (LWR-TRU), and then finally to MTRU (Mixed TRU of LTRU and recycled TRU). At the same time, the core configurations will be modified to meet the nuclear design requirements. Therefore, there is also a strong need to ensure a proper cooling capability during modifications of the entire core. In this work, the core thermal-hydraulic design for U/TRU fuel modification is performed using the SLTHEN (Steady-State LMR Thermal-Hydraulic Analysis Code Based on ENERGY Model) code. As the power distribution in a reactor core is not uniform, it requires a suitable flow allocation to each assembly. There are two ways of allocating the flow rates depending on the orifice positions. The inner officering scheme locates orifice plates in the lower part of the fuel assembly. Therefore, it is possible that the flow distribution is redesigned according to the core configurations. On the other hand, the outer officering scheme fixes orifice plates within the receptacle body throughout the entire plant lifetime. This has the advantage lower of fabrication costs and operating errors but included insufficient design flexibility. This paper provides comparative studies of orifice position for the core thermal-hydraulic design

  16. Steady-state thermal hydraulic analysis and flow channel blockage accident analysis of JRR-4 silicide LEU core

    Energy Technology Data Exchange (ETDEWEB)

    Kaminaga, Masanori; Yamamoto, Kazuyoshi; Watanabe, Shukichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-09-01

    JRR-4 is a light water moderated and cooled, graphite reflected pool type research reactor using high enriched uranium (HEU) plate-type fuels. Its thermal power is 3.5 MW. The core conversion program from HEU fuel to uranium-silicon-aluminum (U{sub 3}Si{sub 2}-Al) dispersion type fuel (Silicide fuel) with low enriched uranium (LEU) is currently conducted at the JRR-4. This report describes about the steady-state thermal hydraulic analysis results and the flow channel blockage accident analysis result. In JRR-4, there are two operation mode. One is high power operation mode up to 3.5 MW, under forced convection cooling using the primary and the secondary cooling systems. The other is low power operation mode up to 200 kW, under natural circulation cooling between the reactor core and the reactor pool without the primary and the secondary cooling systems. For the analysis of the high power operation mode under forced convection cooling and the flow channel blockage accident, COOLOD code was used. On the other hand, for the analysis of low power operation under natural convection cooling, COOLOD-N2 code was used. From steady-state thermal hydraulic analysis results of both forced and natural convection cooling, fuel temperature, minimum DNBR etc. meet the design criteria and JRR-4 LEU silicide core has enough safety margin under normal operation conditions. Furthermore, flow channel blockage accident analysis results show that one channel flow blockage accident meet the safety criteria for accident conditions which have been established for JRR-4 LEU silicide core. (author)

  17. Hexamethylenetetramine reaction with graphite oxide (GO as a strategy to increase the thermal stability of GO: synthesis and characterization of a compound

    Directory of Open Access Journals (Sweden)

    ROBSON F. de FARIAS

    2010-04-01

    Full Text Available In this paper, the synthesis and characterization of a GO–hmta compound (GO – graphite oxide; hmta – hexamethylenetetramine are presented. It is shown that the presence of hmta molecules inside the GO matrix, with very strong interactions, stabilize the GO matrix from a thermal point of view. Such a fact could be used to explore possible applications of GO matrix, especially in catalysis.

  18. Thermal properties of Ba{sub 1-x}Sr{sub x}ZrO{sub 3} compounds from microscopic theory

    Energy Technology Data Exchange (ETDEWEB)

    Terki, R. [Laboratoire d' Etude et de Recherche sur les Materiaux, les Procedes et les Surfaces, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort (France); Ecole Polytechnique de Montreal, Genie Physique, Pavillon J. Armand Bombardier, C.P. 6079, Succ. Centre-Ville, Montreal, Que., Canada H3C 3A7 (Canada)], E-mail: rashida_terki@yahoo.fr; Bertrand, G. [Laboratoire d' Etude et de Recherche sur les Materiaux, les Procedes et les Surfaces, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort (France); Aourag, H. [Laboratoire d' Etude et de Prediction de Materiaux, URMER, Universite de Tlemcen, 13000 (Algeria); Coddet, C. [Laboratoire d' Etude et de Recherche sur les Materiaux, les Procedes et les Surfaces, Universite de Technologie de Belfort-Montbeliard, Site de Sevenans, 90010 Belfort (France)

    2008-05-29

    The ground-state equilibrium properties of cubic Ba{sub 1-x}Sr{sub x}ZrO{sub 3} compounds (x = 0, 0.125, 0.25, 0.375 and 0.5) were studied by means of ab initio total energy calculations using the full-potential linearized augmented plane wave (FP-LAPW) method. In this approach, the generalized gradient approximation was used for the exchange-correlation potential. These calculations are the first step in the investigation of thermodynamics of Ba{sub 1-x}Sr{sub x}ZrO{sub 3} compounds. We found out that compressibility decreases with the Sr concentration according to the ionic radii. The sub-stoichiometry also leads to higher hardness of perovskite compounds. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the isothermal bulk modulus, thermal expansion coefficient, specific heats at constant volume and constant pressure as well as Debye temperature were calculated. No experimental data are available and our results are considered as purely predictive. The major trends show that Ba{sub 1-x}Sr{sub x}ZrO{sub 3} compounds tend to maintain their hardness with the temperature increases. Furthermore, the substitution of Sr{sup 2+} at Ba{sup 2+} sites in BaZrO{sub 3} has a noticeable influence on the thermal expansion behavior which makes Ba{sub 1-x}Sr{sub x}ZrO{sub 3} compounds unable to be good candidates for application as thermal barrier coating.

  19. Lattice thermal transport in L a3C u3X4 compounds (X =P ,As ,Sb ,Bi ) : Interplay of anharmonicity and scattering phase space

    Science.gov (United States)

    Pandey, Tribhuwan; Polanco, Carlos A.; Lindsay, Lucas; Parker, David S.

    2017-06-01

    Thermal conductivities of L a3C u3X4 (X =P ,As ,Sb ,Bi ) compounds are examined using first-principles density functional theory and Boltzmann transport methods. We observe a trend of increasing lattice thermal conductivity (κl) with increasing atomic mass, challenging our expectations, as lighter mass systems typically have larger sound speeds and weaker intrinsic scattering. In particular, we find that L a3C u3P4 has the lowest κl, despite having larger sound speed and the most restricted available phase space for phonon-phonon scattering, an important criterion for estimating and comparing κl among like systems. The origin of this unusual behavior lies in the strength of the individual anharmonic phonon scattering matrix elements, which are much larger in L a3C u3P4 than in the heavier L a3C u3B i4 system. Our finding provides insights into the interplay of harmonic and anharmonic properties of complex, low-thermal-conductivity compounds, of potential use for thermoelectric and thermal barrier coating applications.

  20. Molybdenum-99-producing 37-element fuel bundle neutronically and thermal-hydraulically equivalent to a standard CANDU fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Nichita, E., E-mail: Eleodor.Nichita@uoit.ca; Haroon, J., E-mail: Jawad.Haroon@uoit.ca

    2016-10-15

    Highlights: • A 37-element fuel bundle modified for {sup 99}Mo production in CANDU reactors is presented. • The modified bundle is neutronically and thermal-hydraulically equivalent to the standard bundle. • The modified bundle satisfies all safety criteria satisfied by the standard bundle. - Abstract: {sup 99m}Tc, the most commonly used radioisotope in diagnostic nuclear medicine, results from the radioactive decay of {sup 99}Mo which is currently being produced at various research reactors around the globe. In this study, the potential use of CANDU power reactors for the production of {sup 99}Mo is investigated. A modified 37-element fuel bundle, suitable for the production of {sup 99}Mo in existing CANDU-type reactors is proposed. The new bundle is specifically designed to be neutronically and thermal-hydraulically equivalent to the standard 37-element CANDU fuel bundle in normal, steady-state operation and, at the same time, be able to produce significant quantities of {sup 99}Mo when irradiated in a CANDU reactor. The proposed bundle design uses fuel pins consisting of a depleted-uranium centre surrounded by a thin layer of low-enriched uranium. The new molybdenum-producing bundle is analyzed using the lattice transport code DRAGON and the diffusion code DONJON. The proposed design is shown to produce 4081 six-day Curies of {sup 99}Mo activity per bundle when irradiated in the peak-power channel of a CANDU core, while maintaining the necessary reactivity and power rating limits. The calculated {sup 99}Mo yield corresponds to approximately one third of the world weekly demand. A production rate of ∼3 bundles per week can meet the global demand of {sup 99}Mo.

  1. Computer calculations of the thermally-induced magnetic and electronic properties of the rare earth compounds RERu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Michalski, R. [Inst. of Physics, Pedagocial Univ., Cracow (Poland); Radwanski, R.J. [Center for Solid State Physics, Cracow (Poland)

    2005-07-01

    The aim of this paper is to demonstrate the effectiveness of the calculation method, which takes into consideration the electrostatic ligands field as well as the the magnetic interactions. Our calculations method based on crystal field (CEF) together with the Zeeman effect in one Hamiltonian and allows calculating many of the temperature dependencies of the magnetic and electronic properties of the rare earth compounds. The result of the calculations shows the accuracy of the approach even for the intermetallic compounds. The obtained results for calculations of the compounds of the family in RERu{sub 2}Si{sub 2} (RE - rare-earth element) are fully confirmed the experimental data such as: the easy magnetic direction of all the analyzed compounds, the thermal dependencies of magnetic properties; in particular the giant magnetocrystalline anisotropy of PrRu{sub 2}S{sub 2} with the calculated anisotropy field B{sub A}>400T, in-plain anisotropy of ErRu{sub 2}Si{sub 2}, the cause of difficulty in magnetic ordering of compounds TmRu{sub 2}Si{sub 2} and YbRu{sub 2}Si{sub 2} as well as effects and dependencies not foreseen before. In this paper we have put together the elementary calculated magnetic properties for the chosen compounds of RERu{sub 2}Si{sub 2} in the paramagnetic region. All Calculations are on the basis of the calculating computer package BIREC 1.5{sup 1}. (orig.)

  2. Structural stability, mechanical properties, electronic structures and thermal properties of XS (X = Ti, V, Cr, Mn, Fe, Co, Ni) binary compounds

    Science.gov (United States)

    Liu, Yangzhen; Xing, Jiandong; Fu, Hanguang; Li, Yefei; Sun, Liang; Lv, Zheng

    2017-08-01

    The properties of sulfides are important in the design of new iron-steel materials. In this study, first-principles calculations were used to estimate the structural stability, mechanical properties, electronic structures and thermal properties of XS (X = Ti, V, Cr, Mn, Fe, Co, Ni) binary compounds. The results reveal that these XS binary compounds are thermodynamically stable, because their formation enthalpy is negative. The elastic constants, Cij, and moduli (B, G, E) were investigated using stress-strain and Voigt-Reuss-Hill approximation, respectively. The sulfide anisotropy was discussed from an anisotropic index and three-dimensional surface contours. The electronic structures reveal that the bonding characteristics of the XS compounds are a mixture of metallic and covalent bonds. Using a quasi-harmonic Debye approximation, the heat capacity at constant pressure and constant volume was estimated. NiS possesses the largest CP and CV of the sulfides.

  3. Stability of selected organic compounds on solid adsorbents for thermal desorption gas chromatographic and mass spectrometric characterisation of workroom air.

    OpenAIRE

    Volden, Jon

    2003-01-01

    There is a growing interest in the characterisation of volatile organic compounds (VOCs) in workroom air because of the potentially adverse health effects of these compounds. Volatile organic compounds have intrinsic properties as they vaporise easily and penetrate deep into the lungs were they can be transported to a number of target organs. The VOCs selected for this study were methylethylketone, methylisobutylketone, benzene, toluene, perchloroethylene, butylacetate, decane, limonene, ...

  4. Optimization study and neutronic and thermal-hydraulic design calculations of a 75 KWTH aqueous homogeneous reactor for medical isotopes production

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Daniel Milian; Lorenzo, Daniel E. Milian; Garcia, Lorena P. Rodriguez; Llanes, Jesus Salomon; Hernandez, Carlos R. Garcia, E-mail: dperez@instec.cu, E-mail: dmilian@instec.cu, E-mail: lorenapilar@instec.cu, E-mail: cgh@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas (InSTEC), La Habana (Cuba); Lira, Carlos A. Brayner de Oliveira, E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Rodriguez, Manuel Cadavid, E-mail: mcadavid2001@yahoo.com [Tecnologia Nuclear Medica Spa, TNM (Chile)

    2015-07-01

    {sup 99m}Tc is the most common radioisotope used in nuclear medicine. It is a very useful radioisotope, which is used in about 30-40 million procedures worldwide every year. Medical diagnostic imaging techniques using {sup 99m}Tc represent approximately 80% of all nuclear medicine procedures. Although {sup 99m}Tc can be produced directly on a cyclotron or other type of particle accelerator, currently is almost exclusively produced from the beta-decay of its 66-h parent {sup 99}Mo. {sup 99}Mo production system in an Aqueous Homogeneous Reactor (AHR) is potentially advantageous because of its low cost, small critical mass, inherent passive safety, and simplified fuel handling, processing and purification characteristics. In this paper, an AHR conceptual design using Low Enriched Uranium (LEU) is studied and optimized for the production of {sup 99}Mo. Aspects related with the neutronic behavior such as optimal reflector thickness, critical height, medical isotopes production and the reactivity feedback introduced in the solution by the volumetric expansion of the fuel solution due to thermal expansion of the fuel solution and the void volume generated by radiolytic gas bubbles were evaluated. Thermal-hydraulics studies were carried out in order to show that sufficient cooling capacity exists to prevent fuel overheating. The neutronic and thermal-hydraulics calculations have been performed with the MCNPX computational code and the version 14 of ANSYS CFX respectively. The neutronic calculations demonstrated that the reactor is able to produce 370 six-day curies of {sup 99}Mo in 5 days operation cycles and the CFD simulation demonstrated that the heat removal systems provide sufficient cooling capacity to prevent fuel overheating, the maximum temperature reached by the fuel (89.29 deg C) was smaller to the allowable temperature limit (90 deg C). (author)

  5. Ab initio study of the structural, electronic, elastic and thermal properties of RMn{sub 2}Ge{sub 2} (R = Ca, Nd and Y) intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Miloud Abid, O.; Yakoubi, A. [Laboratoire d’Etudes des Matériaux et Instrumentations Expérimentales, Université Djilali Liabes de Sidi Bel-Abbes, 22000 (Algeria); Tadjer, A. [Modeling and Simulation in Materials Science Laboratory, Physics Department, University of Sidi Bel-Abbes, Sidi Bel-Abbes (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique de la Modélisation Mathématique (LPQ3M), Université de Mascara, 29000 (Algeria); Ahmed, R. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Murtaza, G. [Materials Modeling Laboratory, Department of Physics, Islamia College University, Peshawar (Pakistan); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Azam, Sikander [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic)

    2014-12-15

    Highlights: • The calculated structural parameters of RMn{sub 2}Ge{sub 2} (R = Ca, Nd and Y) compounds are found in good agreement with the experimental data. • The structural and band structure calculation reveals that these compounds are ferromagnetic brittle metals. • The elastic and thermodynamic properties for the herein studied compounds are investigated for the first time. - Abstract: Intermetallic RMn{sub 2}Ge{sub 2} ternary compounds have attracted considerable attention from researchers in recent years because they show strong indications for novel magnetic characteristics and they have the potential to reveal the mechanism of superlattices. The study of the paramagnetic, ferromagnetic and antiferromagnetic phases affirms the strong dependence to the distance between atomic species in these compounds. In this study, we investigated the structural, elastic, electronic and thermodynamic properties of the intermetallic RMn{sub 2}Ge{sub 2} (R = Ca, Nd and Y) compounds. To carry out this study, we used the full potential (FP) linearized (L) augmented plane wave plus local orbitals (APW + lo), a scheme of calculations developed within the frame work of density functional theory (DFT). To incorporate the exchange correlation (XC) energy and corresponding potential into the total energy calculations, local density approximation (LDA) parameterized by Perdew and Wang is taken into account. Analysis of the density of states (DOS) profile illustrates the conducting nature of these intermetallic compounds; with a predominantly contribution from the R and Mn-d states. At ambient conditions, calculations for elastic constants (C{sub 11}, C{sub 12}, C{sub 13}, C{sub 44}, C{sub 33} and C{sub 66}) are also performed, which point to their brittle character. In addition, the quasi harmonic Debye model was used to predict the thermal properties, together with relative expansion coefficients and heat capacity.

  6. Spin-glass-like behavior and negative thermal expansion in antiperovskite Mn{sub 3}Ni{sub 1−x}Cu{sub x}N compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Lei [Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, 100191 Beijing (China); Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38000 Grenoble (France); Wang, Cong, E-mail: congwang@buaa.edu.cn; Sun, Ying [Center for Condensed Matter and Materials Physics, Department of Physics, Beihang University, 100191 Beijing (China); Colin, Claire V. [Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38000 Grenoble (France); Chu, Lihua [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, School of Renewable Energy, North China Electric Power University, Beijing 102206 (China)

    2015-06-07

    The Cu-doping effect on the lattice and magnetic properties in Mn{sub 3}Ni{sub 1−x}Cu{sub x}N (x = 0, 0.3, 0.5, 0.7, 1.0) was extensively investigated. We observed that the Cu-doping at the Ni site complicated the magnetic ground states, which induced the competition of antiferromagnetic and ferromagnetic interactions. Spin-glass-like behavior, arising from possible site-randomness and competing interactions of magnetism, was observed in compounds with x = 0.3, 0.5, and 0.7, and typically discussed by means of the measurement of ac magnetic susceptibility for x = 0.7. The negative thermal expansion (NTE) behavior, due to the magnetic ordering transition, was observed in Mn{sub 3}Ni{sub 1−x}Cu{sub x}N compounds using variable temperature x-ray diffraction. It reveals that the introduction of Cu effectively broadens the temperature range displaying negative thermal expansion. The relationship between the local lattice distortion and the competing magnetic ground states might play an important role in broadening the NTE temperature range in this antiperovskite compound.

  7. Preparation, morphologies and thermal behavior of high nitrogen compound 2-amino-4,6-diazido-s-triazine and its derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qi-Long, E-mail: terry.well@163.com [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Musil, Tomáš [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Zeman, Svatopluk, E-mail: svatopluk.zeman@upce.cz [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Matyáš, Robert [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Shi, Xiao-Bing [Xi‘an Modern Chemistry Research Institute, 710065 Xi’an (China); Vlček, Milan [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 12006 Prague (Czech Republic); Pelikán, Vojtěch [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic)

    2015-03-20

    Graphical abstract: High nitrogen compound 2-amino-4,6-diazido-s-triazine (DAAT) can be substituted by different function groups, forming many other new energetic materials. Such materials that have very close molecular structure may be very different in terms of crystal structure, thermal behavior, as well as performances (e.g., TAAT vs. TAHT). Generally, the increase of the molecular weight results in better thermal stability. - Highlights: • The crystal morphologies of azido-triazine derivatives are examined using SEM. • The thermal stability and decomposition processes are compared by TGA and DSC. • The effect of function group on the thermal behavior of title compounds is clarified. - Abstract: The crystal morphologies, thermal behavior, sensitivity and performance of 2-amino-4,6,-diazido-s-triazine and its derivatives have been investigated using SEM, DSC, TG techniques and related theories. It has been shown that the DANT crystal is in 1–5 μm thickness layered regular hexagon structure with severe agglomeration. DAAT crystal is very hydrophobic and can be dispersed in water, which has layered rectangle structure with thickness less than 0.5 μm. The TAHT materials exist in a form of amorphous irregular particles with diameters of more than 200 μm while its analogue TAAT can be crystallized in needle shape with a length of 30 μm. TNADAzT crystal has a shape of regular polyhedron with average size of about 120 μm. The thermal analysis indicates that there is only one complex step for decomposition of DAAT, while at least three steps are included for the other materials. DAAT started to decompose at around 148.4 °C with a peak temperature of 197.0 °C, while TAHT started to decompose at 167.2 °C with shoulder-peak of 193.4–206.7 °C at the heating rate of 2.0 °C min{sup −1}. DANT decomposes with a heat release of 2420–2721 J g{sup −1}, which is much higher than that of DAAT indicating that the heat and its release rate are greatly

  8. Low-temperature abnormal thermal expansion property of Mn doped cubic NaZn13-type La(Fe, Al)13 compounds

    Science.gov (United States)

    Zhao, Yuqiang; Huang, Rongjin; Shan, Yi; Wang, Wei; Li, Jiangtao; Li, Laifeng

    2017-09-01

    Low-temperature abnormal thermal expansion (ATE) materials have been recently developed because of their significant applications for cryogenic engineering. However, the challenge still remains for the control of ATE effect at cryogenic temperature and adjustable ATE is of fundamental interest. In this paper, we report the isotropic ATE in La(Fe, Al)13 compounds over a wide adjusting temperature range by partially substituting Fe by Mn. It is found that all samples crystallize in the cubic NaZn13-type structure with the Fm\\bar{3}c space group. The introduction of nonmagnetic Mn atoms reduces the Fe-Fe exchange interaction, therefore, the itinerant electron system needs less energy to break the magnetic order in ferromagnetic (FM) state at low temperature. The negative thermal expansion (NTE) operation-temperature window moves towards lower temperatures accompanied with the decrease of Curie temperature (T C) by increasing Mn elements. Moreover, the composite combining Mn 0 and Mn 57 broadens the zero thermal expansion (ZTE) behavior occurring in the whole tested temperature range. The present studies could be useful to control the thermal expansion, and indicate the potential applications of ATE materials in cryogenic engineering.

  9. Electron-phonon interaction and thermal boundary resistance at the crystal-amorphous interface of the phase change compound GeTe

    Energy Technology Data Exchange (ETDEWEB)

    Campi, Davide; Bernasconi, Marco, E-mail: marco.bernasconi@mater.unimib.it [Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125, Milano (Italy); Donadio, Davide [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany); Sosso, Gabriele C. [Computational Science, Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, via Giuseppe Buffi 13, CH-6900 Lugano (Switzerland); Behler, Jörg [Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstrasse 150, D-44780 Bochum (Germany)

    2015-01-07

    Phonon dispersion relations and electron-phonon coupling of hole-doped trigonal GeTe have been computed by density functional perturbation theory. This compound is a prototypical phase change material of interest for applications in phase change non-volatile memories. The calculations allowed us to estimate the electron-phonon contribution to the thermal boundary resistance at the interface between the crystalline and amorphous phases present in the device. The lattice contribution to the thermal boundary resistance has been computed by non-equilibrium molecular dynamics simulations with an interatomic potential based on a neural network scheme. We find that the electron-phonon term contributes to the thermal boundary resistance to an extent which is strongly dependent on the concentration and mobility of the holes. Further, for measured values of the holes concentration and electrical conductivity, the electron-phonon term is larger than the contribution from the lattice. It is also shown that the presence of Ge vacancies, responsible for the p-type degenerate character of the semiconductor, strongly affects the lattice thermal conductivity of the crystal.

  10. Electron-phonon interaction and thermal boundary resistance at the crystal-amorphous interface of the phase change compound GeTe

    Science.gov (United States)

    Campi, Davide; Donadio, Davide; Sosso, Gabriele C.; Behler, Jörg; Bernasconi, Marco

    2015-01-01

    Phonon dispersion relations and electron-phonon coupling of hole-doped trigonal GeTe have been computed by density functional perturbation theory. This compound is a prototypical phase change material of interest for applications in phase change non-volatile memories. The calculations allowed us to estimate the electron-phonon contribution to the thermal boundary resistance at the interface between the crystalline and amorphous phases present in the device. The lattice contribution to the thermal boundary resistance has been computed by non-equilibrium molecular dynamics simulations with an interatomic potential based on a neural network scheme. We find that the electron-phonon term contributes to the thermal boundary resistance to an extent which is strongly dependent on the concentration and mobility of the holes. Further, for measured values of the holes concentration and electrical conductivity, the electron-phonon term is larger than the contribution from the lattice. It is also shown that the presence of Ge vacancies, responsible for the p-type degenerate character of the semiconductor, strongly affects the lattice thermal conductivity of the crystal.

  11. Effects of counterions of colorful sandwich-type zinc(II) 4‧-phenyl-terpyridine compounds on photoluminescent and thermal properties

    Science.gov (United States)

    Zhang, Yongqiang; Zhou, Peng; Liang, Baohuan; Huang, Ling; Zhou, Yanling; Ma, Zhen

    2017-10-01

    Reactions between 4‧-phenyl-terpyridine (L) and several Zn(II) salts (p-toluenesulfonate, nitrate, trifluoromethane sulfonate or hexafluoroantimonate) led to the formation of the complexes [ZnL2](p-OSO2PhCH3)2 (1), [ZnL2](NO3)2 (2), [ZnL2](SO3CF3)2 (3) and [ZnL2](SbF6)2 (4), which were characterized by IR, 1H NMR, elemental analysis, UV-vis spectroscopies and single crystal X-ray diffraction, along with their TG-DTA thermal and photoluminescent properties. The four compounds show mononuclear Zn(II) structures with hexacoordinated, irregular ZnN6 octahedron geometries. Their colours and photo-luminescent properties have changed regularly depending on the counterions of the compounds.

  12. Biochemical degradation and physical migration of nutritive compounds in blueberries after PEF and thermal pretreatments and osmotic dehydration

    Science.gov (United States)

    Fresh blueberries were pretreated by pulsed electric fields (PEF) at 3 kV/cm or thermal pretreatment at 90 degrees C for 5 min after which they were subject to osmotic dehydration. The changes in contents of anthocyanins, predominantly phenolic acids and flavonols, total phenolics, polyphenol oxidas...

  13. The impacts of exposure to organic compounds occurrence of natural origin in thermal water on health in Békés, Hungary.

    Science.gov (United States)

    Hassanien, M A; Dura, G

    2000-07-01

    Deep thermal well (75 degrees C) in Békés county, South East Hungary has been studied. The chemical measurements showed that the thermal water coming from deep geological layers (> 800 m) contains up to 117.2, 35.2, 30.2 and 26 micrograms/l of benzene, toluene, ethylbenzene, and xylenes, respectively. The objectives of this study are: to measure these naturally occurring compounds; estimating to potential risk and hazard index for the population who are using this well mainly for swimming and health baths; assessing the relationship between exposure to environmental chemical and human health; and to stimulate thinking about possible broader uses of risk assessment in identifying and solving public health problems. This paper is not intended as a complete study concerning the four measured compounds. A particular emphasis on benzene which is highly toxic and carcinogenic has been paid. The exposure assessment of benzene based on Risk Assistant model was done. The results showed that the Hazard Quotient (H.Q.) for benzene is more than 1 (requiring actions) and the probability of getting cancer from this exposure is 8E-5 exhibiting high risk for exposed population.

  14. Trends in negative thermal expansion behavior for AMO 2 ( A=Cu or Ag; M=Al, Sc, In, or La) compounds with the delafossite structure

    Science.gov (United States)

    Li, J.; Sleight, A. W.; Jones, C. Y.; Toby, B. H.

    2005-01-01

    Powder neutron diffraction data were obtained from 30 to 600 K for CuAlO 2, CuInO 2, CuLaO 2, 2H CuScO 2, 3R CuScO 2, and AgInO 2. Rietveld refinements of these data showed negative thermal expansion (NTE) of the O-Cu-O linkage in all cases. This behavior was especially strong for CuLaO 2 and CuScO 2, where it persisted up to our maximum measuring temperature of 600 K. This NTE in turn caused NTE of the c cell edge, which was moderated by the positive thermal expansion of the M-O bonds. The NTE behavior increases in the Cu MO 2 series as the size of M increases. No NTE behavior was found for the O-Ag-O linkage in AgInO 2; nonetheless, this compound did exhibit NTE for the c cell edge at low temperatures. For CuLaO 2 there is NTE for both the a and c cell edges at low temperatures. Structural trends for compounds with the delafossite structure are discussed with respect to both composition and temperature.

  15. Influence of thermal treatment on the stability of phenolic compounds and the microbiological quality of sucrose solution following osmotic dehydration of highbush blueberry fruits.

    Science.gov (United States)

    Kucner, Anna; Papiewska, Agnieszka; Klewicki, Robert; Sójka, Michał; Klewicka, Elżbieta

    2014-01-01

    Osmotic dehydration is a process of the partial removal of water which is based on immersion of material having cellular structure in a hypertonic solution. Osmotic dehydration is used as a pretreatment for the dehydration of foods before they are subjected to further processing such as freezing, freeze drying, vacuum drying. Management of spent syrup is one of the most important problems related to osmotic dewatering. Osmotic solutions are heavily polluted with of carbohydrates, remains of the dehydrated material and microorganisms. The aim of this study was to determine the effect of thermal treatment on the content of phenolic compounds and the microbiological quality of sucrose solution used in 15 cycles of osmotic dehydration of highbush blueberry (Vaccinium corymbosum L.) fruits. The tested material was 65.0 ±0.5°Brix sucrose solution used for 15 cycles of osmotic dehydration of highbush blueberry (Vaccinium corymbosum L.). Osmotic dehydration was conducted at 40°C for 120 min using fruits previously subjected to enzymatic pretreatment. The thermal treatment of sucrose solution was conducted at 70, 80, 90, 100 and 115°C for 20, 40 and 60 s. The sucrose solution was analysed in terms of total polyphenols, particular polyphenols using high performance liquid chromatography and microbiological analysis was subjected. Thermal treatment at 70-115°C for 20 s caused degradation of 8.5% to 12.7% of polyphenols, while as much as 23.1% of polyphenols were degraded at 115°C after 60 s. The present paper proposes heating parameters that are optimal from the point of view of phenolic compound retention and microbiological quality: thermal treatment of syrup at 100°C for 40 s. Under these conditions, total polyphenols retention was 94.5%, while the retention of individual phenolic compounds varied from 89.2% to 37.2%, and that of flavan-3-ols amounted to 89.5%. The studied manner of syrup treatment eliminated the problem of syrup contamination with yeasts and molds

  16. Some new nano-structure zinc(II) coordination compounds of an imidazolidine Schiff base: spectral, thermal, antimicrobial properties and DNA interaction.

    Science.gov (United States)

    Montazerozohori, Morteza; Musavi, Sayed Alireza; Naghiha, Asghar; Zohour, Mostafa Montazer

    2014-08-14

    Some novel nano-sized structure zinc complexes of a new Schiff base ligand entitled as (3-nitro-benzylidene)-{2-[2-(3-nitro-phenyl)-imidazolidine-1-yl]-ethyl}-amine(L) with general formula of ZnLX2 wherein X=Cl(-), Br(-), I(-), SCN(-) and N3(-) have been synthesized under ultrasonic conditions. The ligand and its complexes have been characterized by elemental analysis, molar conductance measurements, FT-IR, (1)H and (13)C NMR and UV-Visible spectroscopy. The resulting data from spectral investigation especially (1)H and (13)C NMR well confirmed formation of an imidazolidine ring in the ligand structure. Transmission electron microscopy (TEM) showed nano-size structures with average particle sizes of 21.80-78.10nm for the zinc(II) Schiff base complexes. The free Schiff base and its Zn(II) complexes have been screened in vitro both for antibacterial activity against some gram-positive and gram-negative bacteria and also for antifungal activity. The metal complexes were found to be more active than the free Schiff base ligand. The results showed that ZnL(N3)2 is the most effective inhibitor against Escherichia coli, Pseudomonas aereuguinosa, Staphylococcus aureus and Candida albicans while ZnLBr2 was found to be more effective against Bacillus subtillis than other compounds. Moreover, DNA cleavage potential of all compounds with plasmid DNA was investigated. The results showed that the ligand and ZnLCl2 complex cleave DNA more efficiently than others. In final, thermal analysis of ligand and its complexes revealed that they are decomposed via 2-3 thermal steps in the range of room temperature to 1000°C. Furthermore some activation kinetic parameters such as A, E(*), ΔH(*), ΔS(*) and ΔG(*) were calculated based on TG/DTA plots by use of coats - Redfern relation. Positive values of activation energy evaluated for the compounds confirmed the thermal stability of them. In addition to, the positive ΔH(*), and ΔG(*) values suggested endothermic character for the

  17. Characterization of volatile organic compounds from human analogue decomposition using thermal desorption coupled to comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry.

    Science.gov (United States)

    Stadler, Sonja; Stefanuto, Pierre-Hugues; Brokl, Michał; Forbes, Shari L; Focant, Jean-François

    2013-01-15

    Complex processes of decomposition produce a variety of chemicals as soft tissues, and their component parts are broken down. Among others, these decomposition byproducts include volatile organic compounds (VOCs) responsible for the odor of decomposition. Human remains detection (HRD) canines utilize this odor signature to locate human remains during police investigations and recovery missions in the event of a mass disaster. Currently, it is unknown what compounds or combinations of compounds are recognized by the HRD canines. Furthermore, a comprehensive decomposition VOC profile remains elusive. This is likely due to difficulties associated with the nontarget analysis of complex samples. In this study, cadaveric VOCs were collected from the decomposition headspace of pig carcasses and were further analyzed using thermal desorption coupled to comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (TD-GC × GC-TOFMS). Along with an advanced data handling methodology, this approach allowed for enhanced characterization of these complex samples. The additional peak capacity of GC × GC, the spectral deconvolution algorithms applied to unskewed mass spectral data, and the use of a robust data mining strategy generated a characteristic profile of decomposition VOCs across the various stages of soft-tissue decomposition. The profile was comprised of numerous chemical families, particularly alcohols, carboxylic acids, aromatics, and sulfides. Characteristic compounds identified in this study, e.g., 1-butanol, 1-octen-3-ol, 2-and 3-methyl butanoic acid, hexanoic acid, octanal, indole, phenol, benzaldehyde, dimethyl disulfide, and trisulfide, are potential target compounds of decomposition odor. This approach will facilitate the comparison of complex odor profiles and produce a comprehensive VOC profile for decomposition.

  18. Unusual Low-Energy Phonon Dynamics in the Negative Thermal Expansion Compound ZrW2O8

    Science.gov (United States)

    Hancock, Jason N.; Turpen, Chandra; Schlesinger, Zack; Kowach, Glen R.; Ramirez, Arthur P.

    2004-11-01

    An infrared study of the phonon spectra of ZrW2O8 as a function of temperature which includes the low-energy (2 10meV) region relevant to negative thermal expansion is reported and discussed in the context of specific heat and neutron density of state results. The prevalence of infrared active phonons at low energy and their observed temperature dependence are highly unusual and indicative of exotic low-energy lattice dynamics. Eigenvector calculations indicate a mixing of librational and translational motion within each low-frequency IR mode. The role of the underconstrained structure in establishing the nature of these modes and the relationship between the IR spectra and the large negative thermal expansion in ZrW2O8 are discussed.

  19. Manipulating the adhesion of electroless nickel-phosphorus film on silicon wafers by silane compound modification and rapid thermal annealing

    OpenAIRE

    Hsu, Chin-Wei; Wang, Wei-Yen; Wang, Kuan-Ting; Chen, Hou-An; Wei, Tzu-Chien

    2017-01-01

    In this study, the effect of 3-2-(2-aminoethylamino) ethylamino propyl trimethoxysilane (ETAS) modification and post rapid thermal annealing (RTA) treatment on the adhesion of electroless plated nickel-phosphorus (ELP Ni-P) film on polyvinyl alcohol-capped palladium nanoclusters (PVA-Pd) catalyzed silicon wafers is systematically investigated. Characterized by pull-off adhesion, atomic force microscopy, X-ray spectroscopy and water contact angle, a time-dependent, three-staged ETAS grafting m...

  20. Analysis of the Effect of Construction and Operation of Thermal Expansion System Compounds on Steam Turbines Reliability

    Science.gov (United States)

    Murmansky, B. E.; Sosnovsky, A. Yu.; Brodov, Yu. M.

    2017-11-01

    The inspection results are presented of turbines of different types and capacity, showing the influence of various factors (such as increased frictional forces on the mating surfaces, clearance changes in the joints elements, TES elements design, state of the thermal expansions compensation system of pipelines) on the operation both of thermal expansion system and of the turbine as a whole. The data are presented on the effectiveness of various measures aimed to eliminate the causes of the turbine thermal expansion system deviations from its normal operation. The results are shown of the influence simulation of various factors (such as flanges and piping warming, ratio of clearance changes in the elements) on the probability of turbine TES hindrance. It is shown that clearance ratios employed in most turbines do not provide the stability of turbine TES against the external action of connected pipes. The simulation results permit to explain the bearing housings turns observed during inspections, resulting in a jam on the longitudinal keys, in temperature distribution changes on the thrust bearing pads, and in some cases in false readings of instruments rotor axial displacement.

  1. Treatment Efficiency by means of a Nonthermal Plasma Combined with Heterogeneous Catalysis of Odoriferous Volatile Organic Compounds Emissions from the Thermal Drying of Landfill Leachates

    Directory of Open Access Journals (Sweden)

    Daniel Almarcha

    2014-01-01

    Full Text Available The objective of the present work was to assess the odoriferous volatile organic compounds depuration efficiency of an experimental nonthermal plasma coupled to a catalytic system used for odor abatement of real emissions from a leachate thermal drying plant installed in an urban solid waste landfill. VOC screening was performed by means of HRGC-MS analysis of samples taken at the inlet and at the outlet of the nonthermal plasma system. Odor concentration by means of dynamic olfactometry, total organic carbon, mercaptans, NH3, and H2S were also determined in order to assess the performance of the system throughout several days. Three plasma frequencies (100, 150, and 200 Hz and two catalyst temperatures (150°C and 50°C were also tested. Under conditions of maximum capacity of the treatment system, the results show VOC depuration efficiencies around 69%, with average depuration efficiencies between 44 and 95% depending on the chemical family of the substance. Compounds belonging to the following families have been detected in the samples: organic acids, alcohols, ketones, aldehydes, pyrazines, and reduced sulphur compounds, among others. Average total organic carbon removal efficiency was 88%, while NH3 and H2S removal efficiencies were 88% and 87%, respectively, and odor concentration abatement was 78%.

  2. Effect of thermal processing on the profile of bioactive compounds and antioxidant capacity of fermented orange juice.

    Science.gov (United States)

    Escudero-López, Blanca; Cerrillo, Isabel; Gil-Izquierdo, Ángel; Hornero-Méndez, Dámaso; Herrero-Martín, Griselda; Berná, Genoveva; Medina, Sonia; Ferreres, Federico; Martín, Franz; Fernández-Pachón, María-Soledad

    2016-11-01

    Previously, we reported that alcoholic fermentation enhanced flavanones and carotenoids content of orange juice. The aim of this work was to evaluate the influence of pasteurization on the qualitative and quantitative profile of bioactive compounds and the antioxidant capacity of fermented orange juice. Ascorbic acid (203 mg/L), total flavanones (647 mg/L), total carotenoids (7.07 mg/L) and provitamin A (90.06 RAEs/L) values of pasteurized orange beverage were lower than those of fermented juice. Total phenolic remained unchanged (585 mg/L) and was similar to that of original juice. The flavanones naringenin-7-O-glucoside, naringenin-7-O-rutinoside, hesperetin-7-O-rutinoside, hesperetin-7-O-glucoside and isosakuranetin-7-O-rutinoside, and the carotenoids karpoxanthin and isomer, neochrome, lutein, ζ-carotene, zeaxanthin, mutatoxanthin epimers, β-cryptoxanthin and auroxanthin epimers were the major compounds. Pasteurization produced a decrease in antioxidant capacity of fermented juice. However, TEAC (5.45 mM) and ORAC (6353 μM) values of orange beverage were similar to those of original orange juice. The novel orange beverage could be a valuable source of bioactive compounds with antioxidant capacity and exert potential beneficial effects.

  3. Bioaccessibility of bioactive compounds after non-thermal processing of an exotic fruit juice blend sweetened with Stevia rebaudiana.

    Science.gov (United States)

    Buniowska, Magdalena; Carbonell-Capella, Juana M; Frigola, Ana; Esteve, Maria J

    2017-04-15

    A comparative study of the bioaccessibility of bioactive compounds and antioxidant capacity in a fruit juice-Stevia rebaudiana mixture processed by pulsed electric fields (PEF), high voltage electrical discharges (HVED) and ultrasound (USN) technology at two equivalent energy inputs (32-256kJ/kg) was made using an in vitro model. Ascorbic acid was not detected following intestinal digestion, while HVED, PEF and USN treatments increased total carotenoid bioaccessibility. HVED at an energy input of 32kJ/kg improved bioaccessibility of phenolic compounds (34.2%), anthocyanins (31.0%) and antioxidant capacity (35.8%, 29.1%, 31.9%, for TEAC, ORAC and DPPH assay, respectively) compared to untreated sample. This was also observed for PEF treated samples at an energy input of 256kJ/kg (37.0%, 15.6%, 29.4%, 26.5%, 23.5% for phenolics, anthocyanins, and antioxidant capacity using TEAC, ORAC and DPPH method, respectively). Consequently, pulsed electric technologies (HVED and PEF) show good prospects for enhanced bioaccessibility of compounds with putative health benefit. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Characterization of Key Aroma Compounds in Raw and Thermally Processed Prawns and Thermally Processed Lobsters by Application of Aroma Extract Dilution Analysis.

    Science.gov (United States)

    Mall, Veronika; Schieberle, Peter

    2016-08-24

    Application of aroma extract dilution analysis (AEDA) to an aroma distillate of blanched prawn meat (Litopenaeus vannamei) (BPM) revealed 40 odorants in the flavor dilution (FD) factor range from 4 to 1024. The highest FD factors were assigned to 2-acetyl-1-pyrroline, 3-(methylthio)propanal, (Z)-1,5-octadien-3-one, trans-4,5-epoxy-(E)-2-decenal, (E)-3-heptenoic acid, and 2-aminoacetophenone. To understand the influence of different processing conditions on odorant formation, fried prawn meat was investigated by means of AEDA in the same way, revealing 31 odorants with FD factors between 4 and 2048. Also, the highest FD factors were determined for 2-acetyl-1-pyrroline, 3-(methylthio)propanal, and (Z)-1,5-octadien-3-one, followed by 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E)-3-heptenoic acid, and 2-aminoacetophenone. As a source of the typical marine, sea breeze-like odor attribute of the seafood, 2,4,6-tribromoanisole was identified in raw prawn meat as one of the contributors. Additionally, the aroma of blanched prawn meat was compared to that of blanched Norway and American lobster meat, respectively (Nephrops norvegicus and Homarus americanus). Identification experiments revealed the same set of odorants, however, with differing FD factors. In particular, 3-hydroxy-4,5-dimethyl-2(5H)-furanone was found as the key aroma compound in blanched Norway lobster, whereas American lobster contained 3-methylindole with a high FD factor.

  5. Effect of high-pressure processing and thermal treatment on quality attributes and nutritional compounds of "Songold" plum purée.

    Science.gov (United States)

    González-Cebrino, Francisco; García-Parra, Jesús; Contador, Rebeca; Tabla, Rafael; Ramírez, Rosario

    2012-08-01

    The application of hydrostatic high pressure on a "Songold" plum purée was assessed in comparison with heat pasteurization. To simulate industrial conditions, one-half of the total purée was manufactured with a pretreatment of thermal blanching (TB) and the other half without it (nonthermally blanched, NTB). Changes after thermal treatment and high-pressure processing (HPP: 400, 600 MPa) and after 20 d of refrigerated storage were evaluated. HPP maintained the microbial stability of the purées until the end of the storage period. Polyphenol oxidase activity was lower in TB purées than NTB purées. No treatment was completely effective to stop the enzyme activity, although a significant reduction was reached. Thermally treated purées showed more intense color changes after processing and storage than HP-treated purées. After processing, high-pressure (HP) purées treated at 600 MPa (TB and NTB) increased the extractability of carotenoids compared with initial untreated purée. Nevertheless, at the end of the storage, the highest carotenoid content was found in the TB purée treated at 400 MPa. After processing, total polyphenol levels were similar in all purées. TB and 600 MPa processing was more effective in the maintenance of the polyphenols than the other purées. TB increased the level of antioxidants after storage, compared to NTB purées. A previous TB step is necessary to inactivate browning enzymes before HPP to maintain the levels of bioactive compounds. HPP of plum purée could be a suitable alternative to traditional thermal processing, but more studies are necessary to ensure a major inactivation of polyphenol oxidase. High-pressure processing is one of the most successful technologies to obtain high-quality fruit purées without appreciable losses in taste, flavor, color, and nutritive value. However, for the introduction of a new technology, some advantages compared to the traditional thermal treatment need to be emphasized. The application of

  6. Monocrystal Elastic Constants of the Negative-Thermal-Expansion Compound Zirconium Tungstate (ZrW2O8)

    Science.gov (United States)

    Drymiotis, F. R.; Ledbetter, H.; Betts, J. B.; Kimura, T.; Lashley, J. C.; Migliori, A.; Ramirez, A. P.; Kowach, G. R.; van Duijn, J.

    2004-07-01

    We measured zirconium tungstate's elastic constants Cij. This compound shows relatively soft, nearly isotropic elastic constants with normal Poisson ratios and no approach to Born instability. ZrW2O8 shows normal ambient-temperature elastic constants Cij, but remarkable dCij/dT that show dominant low-frequency acoustic-vibration modes. From the bulk modulus, we estimated the total ambient-temperature thermodynamic Grüneisen parameter as γ=-1.2. The dB/dT slope gives a Grüneisen parameter γ=-7. The 300 0K bulk-modulus increase (40%) seems unprecedented and breaks Birch's law of corresponding states.

  7. Thermal hysteresis in spin-crossover compounds studied within the mechanoelastic model and its potential application to nanoparticles

    Science.gov (United States)

    Stoleriu, Laurentiu; Chakraborty, Pradip; Hauser, Andreas; Stancu, Alexandru; Enachescu, Cristian

    2011-10-01

    The recently developed mechanoelastic model is applied to characterize the thermal transition in spin-crossover complexes, with special attention given to the case of spin-crossover nanoparticles. In a two-dimensional system, hexagonal-shaped samples with open boundary conditions are composed of individual molecules that are linked by springs and can switch between two states, namely, the high-spin (HS) and the low-spin (LS) states. The switching of an individual molecule during the spin transition is decided by way of a Monte Carlo standard procedure, using transition probabilities depending on the temperature, the energy gap between the two states, the enthalpy difference, the degeneracy ratio, and the local pressure determined by the elongation or compression of its closest springs. The influence of external parameters, such as temperature sweeping rate and pressure, or intrinsic features of the system, such as the value of its spring constant, on the width of the thermal hysteresis, its shape, and its position are discussed. The particular case of spin-crossover nanoparticles is treated by considering them embedded into a polymer environment, which essentially affects the molecules situated at the edges and faces by decreasing their transition probabilities from HS to LS. Finally, the pressure hysteresis, obtained by varying the external pressure at constant temperature is discussed.

  8. 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...... identified by GC-MS. While 92 VOCs were detected from the oil used in the floor oil, only 13 were detected in the low-odor linseed oil. The major odor active VOCs were aldehydes and carboxylic acids. Spearmen rank correlation of the GC-O profiles showed that the odor profile of the linseed oil likely...... influenced the odor profile of the floor oil based on this linseed oil....

  9. 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.

  10. Antioxidant Activity and Thermal Stability of Oleuropein and Related Phenolic Compounds of Olive Leaf Extract after Separation and Concentration by Salting-Out-Assisted Cloud Point Extraction

    Directory of Open Access Journals (Sweden)

    Konstantinos Stamatopoulos

    2014-04-01

    Full Text Available A fast, clean, energy-saving, non-toxic method for the stabilization of the antioxidant activity and the improvement of the thermal stability of oleuropein and related phenolic compounds separated from olive leaf extract via salting-out-assisted cloud point extraction (CPE was developed using Tween 80. The process was based on the decrease of the solubility of polyphenols and the lowering of the cloud point temperature of Tween 80 due to the presence of elevated amounts of sulfates (salting-out and the separation from the bulk solution with centrifugation. The optimum conditions were chosen based on polyphenols recovery (%, phase volume ratio (Vs/Vw and concentration factor (Fc. The maximum recovery of polyphenols was in total 95.9%; Vs/Vw was 0.075 and Fc was 15 at the following conditions: pH 2.6, ambient temperature (25 °C, 4% Tween 80 (w/v, 35% Na2SO4 (w/v and a settling time of 5 min. The total recovery of oleuropein, hydroxytyrosol, luteolin-7-O-glucoside, verbascoside and apigenin-7-O-glucoside, at optimum conditions, was 99.8%, 93.0%, 87.6%, 99.3% and 100.0%, respectively. Polyphenolic compounds entrapped in the surfactant-rich phase (Vs showed higher thermal stability (activation energy (Ea 23.8 kJ/mol compared to non-entrapped ones (Ea 76.5 kJ/mol. The antioxidant activity of separated polyphenols remained unaffected as determined by the 1,1-diphenyl-2-picrylhydrazyl method.

  11. Effects of carbon content on structural, magnetic, and electrical/thermal transport properties of antiperovskite compounds GaCxFe3

    Science.gov (United States)

    Lin, S.; Wang, B. S.; Tong, P.; Hu, L.; Huang, Y. N.; Lu, W. J.; Zhao, B. C.; Song, W. H.; Sun, Y. P.

    2013-03-01

    In this paper, we report the effects of carbon content on crystal structure, magnetic and electrical/thermal transport properties in antiperovskite compounds GaCxFe3 (0.15 ≤ x ≤ 0.3). Our experimental results indicate that all the physical properties we measured are sensitive to the carbon concentration for GaCxFe3. With decreasing the carbon content x, the Curie temperature (TC), saturated magnetization, and coercive force (HC) increase while the lattice constant, Debye temperature, and resistivity decrease gradually. Further analysis suggests that the serial GaCxFe3 can be a new kind of promising high-temperature soft magnetic material considering their high-TC (˜788 K) and low-HC (˜22 Oe). Interestingly, the low-temperature resistivity exhibits an abnormal semiconducting behavior below a characteristic temperature for each of GaCxFe3 (0.15 ≤ x ≤ 0.3). This abnormality of resistivity may be attributed to a combination of the renormalized electron-electron interaction and the weak-localization. Furthermore, the studies of the thermal transport and the Hall measurement suggest that the type of dominant carriers in GaCxFe3 changes gradually from hole- to electron-type with decreasing x.

  12. Effect of Graphene Nanosheets on the Morphology, Crystallinity, and Thermal and Electrical Properties of Super Tough Polyamide 6 Using SEBS Compounds

    Directory of Open Access Journals (Sweden)

    Farzaneh Alirezaei Hoor

    2015-01-01

    Full Text Available Super tough polyamide 6 was prepared by using SEBS and effect of SEBS-g-MA as a compatibilizer of PA6/SEBS matrix on mechanical properties was investigated. Thus super tough polyamide 6/graphene nanocomposites were produced using graphene nanosheets (GNs through the melt compounding method. To compare the effectiveness of graphene, effects of graphite and carbon black (the other carbon structures are also studied on the same matrix. The effects of graphene on crystallinity, improvements of morphology, and thermal and electrical properties of the nanocomposites were researched and compared with similar samples of graphite and carbon black. Due to the reaction between the maleic anhydride groups of SEBS and amine groups of nylon chains during the melt mixing process, super tough polyamide 6 was produced with high impact and tensile strength. The most important results of this study can be noted as an increase in the electrical conductivity and thermal stability by adding graphene to PA6/SEBS blend. Also the effect of graphene compatibility on PA6/SEBS/SEBS-g-MA blend was investigated with studying morphology.

  13. Time-dependent categorization of volatile aroma compound formation in stewed Chinese spicy beef using electron nose profile coupled with thermal desorption GC–MS detection

    Directory of Open Access Journals (Sweden)

    Hui Gong

    2017-09-01

    Full Text Available In the present study, flavor profiles of Chinese spiced beef in the cooking process were comparatively analyzed by electronic nose, gas chromatography–mass spectrometry (GC–MS with a thermal desorption system (TDS, and solid-phase microextraction (SPME. A total of 82 volatile compounds were identified, and 3-methyl-butanal, pentanal, hexanal, ρ-xylene, heptanal, limonene, terpinene, octanal, linalool, 4-terpinenol, α-terpineol, and (E-anethole were identified as the characteristic flavor compounds in Chinese spiced beef. Variation in the content of volatile components produced by different cooking processes was observed. In general, a cooking time of 4 h resulted in optimal flavor quality and stability. Results indicated that the electronic nose could profile and rapidly distinguish variation among different cooking time. The volatile profiling by TDS-GC–MS and responses from the electronic nose, in combination with multivariate statistical analysis, are a promising tool for control the cooking process of spiced beef.

  14. Synthesis of Nanocrystals and Particle Size Effects Studies on the Thermally Induced Spin Transition of the Model Spin Crossover Compound [Fe(phen)2(NCS)2].

    Science.gov (United States)

    Valverde-Muñoz, Francisco Javier; Gaspar, Ana B; Shylin, Sergii I; Ksenofontov, Vadim; Real, José A

    2015-08-17

    Surfactant-free nanocrystals of the model spin-crossover compound [Fe(phen)2(NCS)2] (phen: 1,10-phenanthroline) have been synthesized applying the reverse micelle technique. The morphology of the nanocrystals, characterized by scanning electronic microscopy, corresponds to rhombohedric platelets with dimensions ranging from 203 × 203 × 106 nm to 142 × 142 × 74 nm. Variation of the concentration of the Fe(BF4)2·6H2O salt in the synthesis has been found to have little influence on the crystallite size. In contrast, the solvent-surfactant ratio (ω) is critical for a good particle growth. The spin transition of the nanocrystals has been characterized by magnetic susceptibility measurements and Mössbauer spectroscopy. The nanocrystals undergo an abrupt and more cooperative spin transition in comparison with the bulk compound. The spin transition is centered in the interval of temperature of 175-185 K and is accompanied by 8 K of thermal hysteresis width. The crystallite quality more than the crystallite size is responsible for the higher cooperativity. The magnetic properties of the nanocrystals embedded in organic polymers such as polyethylene glycol, nujol, glycerol, and triton have been studied as well. The spin transition in the nanocrystals is affected by the polymer coating. The abrupt and first-order spin transition transforms into a more continuous spin transition as a result of the chemical pressure asserted by the organic polymers on the Fe(II) centers.

  15. Thermal cooking changes the profile of phenolic compounds, but does not attenuate the anti-inflammatory activities of black rice

    Directory of Open Access Journals (Sweden)

    Sassy Bhawamai

    2016-09-01

    Full Text Available Background: Evidence on biological activities of cooked black rice is limited. This study examined the effects of washing and cooking on the bioactive ingredients and biological activities of black rice. Methods: Cooked rice was prepared by washing 0–3 times followed by cooking in a rice cooker. The acidic methanol extracts of raw and cooked rice were used for the analyses. Results: Raw black rice, both washed and unwashed, had higher contents of polyphenols, anthocyanins, and cyanidin-3-glucoside (C3G, but lower protocatechuic acid (PA, than did cooked samples. Similarly, raw rice extracts were higher in ferric-reducing antioxidant power (FRAP activities than extracts of cooked samples. Nonetheless, extracts of raw and cooked rice showed similar inhibitory potencies on nitric oxide, tumor necrosis factor-α, and interleukin-6 productions in lipopolysaccharide-activated macrophages, whereas equivalent amounts of C3G and PA did not possess such inhibitory effects. Conclusions: Thermal cooking decreased total anthocyanin and C3G contents and the FRAP antioxidative capacity, but did not affect anti-inflammatory activities of black rice. Neither C3G nor PA contributed to the anti-inflammatory activity of black rice.

  16. The effect of mineral fillers on the rheological, mechanical and thermal properties of halogen-free flame-retardant polypropylene/expandable graphite compounds

    Science.gov (United States)

    Mattausch, Hannelore; Laske, Stephan; Hohenwarter, Dieter; Holzer, Clemens

    2015-05-01

    In many polyolefin applications, such as electrical cables or automotive applications, the fire protection is a very important task. Unfortunately flame-retardant polymeric materials are often halogenated and form toxic substances in case of fire, which explains the general requirement to reduce the halogen content to zero. Non-halogenated, state-of-the-art flame retardants must be incorporated into the polymer in very high grades (> 40 wt%) leading to massive decrease in mechanical properties and/or processability. In this research work halogen-free flame-retardant polypropylene (PP) /expandable graphite (EG) were filled with minerals fillers such as layered silicates (MMT), magnesium hydroxide (MgOH), zeolite (Z) and expanded perlite (EP) in order to enhance the flame-retardant effect. The rheological, mechanical and thermal properties of these materials were investigated to gain more fundamental knowledge about synergistic combinations of flame-retardants and other additives. The rheological properties were characterized with a rotational rheometer with plate-plate setup. The EG/EP/PP compound exhibited the highest increase in viscosity (˜ 37 %). As representative value for the mechanical properties the Young's modulus was chosen. The final Young's modulus values of the twofold systems gained higher values than the single ones. Thermo gravimetric analysis (TGA) was utilized to investigate the material with respect to volatile substances and combustion behavior. All materials decomposed in one-step degradation. The EG filled compounds showed a significant increase in sample weight due to the expansion of EG. The combustion behavior of these materials was characterized by cone calorimeter tests. Especially combinations of expandable graphite with mineral fillers exhibit a reduction of the peak heat release rate during cone calorimeter measurements of up to 87% compared to pure PP.

  17. Thermally activated persulfate oxidation of NAPL chlorinated organic compounds: effect of soil composition on oxidant demand in different soil-persulfate systems.

    Science.gov (United States)

    Liu, Jialu; Liu, Zhehua; Zhang, Fengjun; Su, Xiaosi; Lyu, Cong

    2017-04-01

    This study investigates the interaction of persulfate with soil components and chlorinated volatile organic compounds (CVOCs), using thermally activated persulfate oxidation in three soil types: high sand content; high clay content; and paddy field soil. The effect of soil composition on the available oxidant demand and CVOC removal rate was evaluated. Results suggest that the treatment efficiency of CVOCs in soil can be ranked as follows: cis-1,2-dichloroethene > trichloroethylene > 1,2-dichloroethane > 1,1,1-trichloroethane. The reactions of soil components with persulfate, shown by the reduction in soil phase natural organics and mineral content, occurred in parallel with persulfate oxidation of CVOCs. Natural oxidant demand from the reaction of soil components with persulfate exerted a large relative contribution to the total oxidant demand. The main influencing factor in oxidant demand in paddy-soil-persulfate systems was natural organics, rather than mineral content as seen with sand and clay soil types exposed to the persulfate system. The competition between CVOCs and soil components for oxidation by persulfate indicates that soil composition exhibits a considerable influence on the available oxidant demand and CVOC removal efficiency. Therefore, soil composition of natural organics and mineral content is a critical factor in estimating the oxidation efficiency of in-situ remediation systems.

  18. The fate of Fe{sup 3+} ions in the system {l_brace}AlO(OH)-xerogel/Fe-compounds{r_brace} after mechanical activation and different thermal treatments studied by Moessbauer, ESR spectroscopy and thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stoesser, R. [Humboldt University, Institute of Chemistry (Germany); Menzel, M., E-mail: Michael.Menzel@bam.de [Federal Institute for Materials Research and Testing (BAM) (Germany); Feist, M. [Humboldt University, Institute of Chemistry (Germany)

    2009-04-15

    Co-milling of AlO(OH) xerogels with various iron(III) compounds such as {alpha}-Fe{sub 2}O{sub 3} or K{sub 3}[Fe(CN){sub 6}] has been used for mechanochemical activation leading to Fe/Al oxide phases in coexistence with the activated main component. The results obtained allow a deeper insight into the chemical processes occurring during activation, doping, and thermal treatment in atmospheres of different chemical activity (H{sub 2}O; N{sub 2}; O{sub 2}/N{sub 2}; H{sub 2}/N{sub 2}). Evidence will be given for Fe{sup 3+} species being able to form suitable crystallization germs and to lower the crystallization temperature. One can distinguish between the incorporation of Fe{sup 3+} ions into the alumina matrix at the crystallite growth (e.g. on Fe{sub 2}O{sub 3}-like seeds) and the incorporation of Fe{sup 3+} ions during the last steps of crystallization. These last-mentioned Fe{sup 3+} ions are provided by coexisting Fe/Al oxide phases. In contrast to alumina matrices equilibrated at high temperatures (e.g. at 1,200-1,500{sup o}C), the matrices formed in situ are able to incorporate Fe{sup 3+} ions by diffusion at temperatures of {approx}900-1,100 deg. C in a short time regime.

  19. Crystal structures and thermal behaviour of double complex compounds incorporating the [Cr{CO(NH2)2}6]3+ cation

    Science.gov (United States)

    Pechenyuk, S. I.; Zolotarev, A. A.; Gosteva, A. N.; Domonov, D. P.; Shimkin, A. A.

    2017-11-01

    Double complex compounds (DCC) of the [Cr(ur)6][Fe(CN)6]·4H2O (I), [Cr(ur)6][Co(CN)6]·4H2O (II), [Cr(ur)6][Fe(Ox)3]·2H2O (III), and [Cr(ur)6][Co(Ox)3].3.5H2O (IV) composition, where ur is CO(NH2)2, Ох - С2О42- have been synthesized and their crystal structures have been studied. The DCC I, II and IV are triclinic (Р-1); III is orthorhombic (С2221). The DCC thermal behavior in air and argon atmospheres was analyzed by the following parameters: the temperature interval of total decomposition and the nature of gaseous and solid products. The end solid products in air were FeO and FeCr2O4 for I, a mixture of СоCr2O4 + Со2CrO4 for II and IV and an X-ray amorphous phase with composition CrFeO2.5 for III. The gaseous products were HCN, NH3, HNCO, N2O, СО, СО2, N2, and urea. The temperatures of total decomposition in air were: I, II 400°С, III - 350°С, IV - 460°С. In argon, the solid residue contained, besides the oxides, 7-30% of carbon up to 1000°С.

  20. X-231A demonstration of in-situ remediation of DNAPL compounds in low permeability media by soil fracturing with thermally enhanced mass recovery or reactive barrier destruction

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L. [Oak Ridge National Lab., TN (United States)]|[Colorado School of Mines, Golden, CO (United States). Environmental Science and Engineering Div.; Lowe, K.S. [Oak Ridge National Lab., Grand Junction, CO (United States). Life Sciences Div.; Murdoch, L.D. [FRx, Inc., Cincinnati, OH (United States)]|[Clemson Univ., SC (United States); Slack, W.W. [FRx, Inc., Cincinnati, OH (United States); Houk, T.C. [Lockheed Martin Energy Systems, Piketon, OH (United States)

    1998-03-01

    The overall goal of the program of activities is to demonstrate robust and cost-effective technologies for in situ remediation of DNAPL compounds in low permeability media (LPM), including adaptations and enhancements of conventional technologies to achieve improved performance for DNAPLs in LPM. The technologies sought should be potential for application at simple, small sites (e.g., gasoline underground storage tanks) as well as at complex, larger sites (e.g., DOE land treatment units). The technologies involved in the X-231A demonstration at Portsmouth Gaseous Diffusion Plant (PORTS) utilized subsurface manipulation of the LPM through soil fracturing with thermally enhanced mass recovery or horizontal barrier in place destruction. To enable field evaluation of these approaches, a set of four test cells was established at the X-231A land treatment unit at the DOE PORTS plant in August 1996 and a series of demonstration field activities occurred through December 1997. The principal objectives of the PORTS X-231A demonstration were to: determine and compare the operational features of hydraulic fractures as an enabling technology for steam and hot air enhanced soil vapor extraction and mass recovery, in situ interception and reductive destruction by zero valent iron, and in situ interception and oxidative destruction by potassium permanganate; determine the interaction of the delivered agents with the LPM matrix adjacent to the fracture and within the fractured zone and assess the beneficial modifications to the transport and/or reaction properties of the LPM deposit; and determine the remediation efficiency achieved by each of the technology strategies.

  1. Thermal properties of Zn2(C8H4O4)2?C6H12N2 metal-organic framework compound and mirror symmetry violation of dabco molecules

    OpenAIRE

    Kozlova, Svetlana G.; Gabuda, Svyatoslav P.

    2017-01-01

    Thermal properties of Zn2(C8H4O4)2?C6H12N2 metal-organic framework compound at 8?300?K suggest the possibility of subbarrier tunnelling transitions between left-twisted (S) and right-twisted (R) forms of C6H12N2 dabco molecules with D3 point symmetry. The data agree with those obtained for the temperature behavior of nuclear spin-lattice relaxation times. It is shown that there is a temperature range where the transitions are stopped. Therefore, Zn2(C8H4O4)2?C6H12N2 and related compounds are ...

  2. Group IB Organometallic Chemistry XXXIV: Thermal behavior and chemical reactivity of tetranuclear Me2N-substituted diarylpropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds

    NARCIS (Netherlands)

    Koten, G. van; Hoedt, R.W.M. ten; Noltes, J.G.

    1980-01-01

    Thermal decomposition of configurationally pure 1, 2-diarylpropenylcopper compounds Z-Vi{2}CU{4}Br{2} and Z-Vi{2}Cu{4}R{2} [Vi @? (2-Me{2}NC{6}H{4})C@?C(Me)-(C{6}H{4}Me-4), R @? 2-Me{2}NC{6}H{4} or 4-MeC{6}H{4}C@?C] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were

  3. Preparation of uranium compounds

    Science.gov (United States)

    Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

    2013-02-19

    UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

  4. Assessment of severe accident source terms in pressurized-water reactors with a 40% mixed-oxide and 60% low-enriched uranium core using MELCOR 1.8.5.

    Energy Technology Data Exchange (ETDEWEB)

    Gauntt, Randall O.; Goldmann, Andrew S. (Texas A& M University, College Station, TX); Wagner, Kenneth C.; Powers, Dana Auburn; Ashbaugh, Scott G.; Longmire, Pamela

    2010-04-01

    As part of a Nuclear Regulatory Commission (NRC) research program to evaluate the impact of using mixed-oxide (MOX) fuel in commercial nuclear power plants, a study was undertaken to evaluate the impact of the usage of MOX fuel on the consequences of postulated severe accidents. A series of 23 severe accident calculations was performed using MELCOR 1.8.5 for a four-loop Westinghouse reactor with an ice condenser containment. The calculations covered five basic accident classes that were identified as the risk- and consequence-dominant accident sequences in plant-specific probabilistic risk assessments for the McGuire and Catawba nuclear plants, including station blackouts and loss-of-coolant accidents of various sizes, with both early and late containment failures. Ultimately, the results of these MELCOR simulations will be used to provide a supplement to the NRC's alternative source term described in NUREG-1465. Source term magnitude and timing results are presented consistent with the NUREG-1465 format. For each of the severe accident release phases (coolant release, gap release, in-vessel release, ex-vessel release, and late in-vessel release), source term timing information (onset of release and duration) is presented. For all release phases except for the coolant release phase, magnitudes are presented for each of the NUREG-1465 radionuclide groups. MELCOR results showed variation of noble metal releases between those typical of ruthenium (Ru) and those typical of molybdenum (Mo); therefore, results for the noble metals were presented for Ru and Mo separately. The collection of the source term results can be used as the basis to develop a representative source term (across all accident types) that will be the MOX supplement to NUREG-1465.

  5. Development of low enriched uranium target plates by thermo-mechanical processing of UAl{sub 2}–Al matrix for production of {sup 99}Mo in Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Kanwar Liaqat; Khan, Akhlaque Ahmad [Pakistan Institute of Nuclear Science and Technology (PINSTECH) P.O Nilore, Islamabad (Pakistan); Mushtaq, Ahmad, E-mail: amushtaq1@hotmail.com [Pakistan Institute of Nuclear Science and Technology (PINSTECH) P.O Nilore, Islamabad (Pakistan); Imtiaz, Farhan; Ziai, Maratab Ali; Gulzar, Amir; Farooq, Muhammad; Hussain, Nazar; Ahmed, Nisar; Pervez, Shahid; Zaidi, Jamshed Hussain [Pakistan Institute of Nuclear Science and Technology (PINSTECH) P.O Nilore, Islamabad (Pakistan)

    2013-02-15

    Uranium aluminide predominated with UAl{sub 2} phase was prepared by arc-melting procedures and comminuted to required particle size. UAl{sub 2} and Al powders were blended and compacted to achieve LEU fuel density of 2.17 g/cm{sup 3}. The picture-frame technique was used to clad the dispersions (UAl{sub 2}–Al) with aluminum. A few target plates were fabricated by thermo-mechanical processing (hot rolling and annealing) of UAl{sub 2}–Al matrix contained in roll billet of Al. The fabricated plates were characterized by destructive and some of non-destructive testing techniques and then annealed to achieve required phase of uranium aluminide for proper dissolution in basic media.

  6. Neutronic and thermal-hydraulic analysis of a device for irradiation of LEU UAl{sub x}-Al targets for {sup 99}Mo production in the IEA-R1 reactor; Analises neutronica e termo-hidraulica de um dispositivo para irradiacao de alvos tipo LEU de UAl{sub x}-Al para producao de {sup 99}MO no reator IEA-R1

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, Pedro Julio Batista de Oliveira

    2012-07-01

    Technetium-99m ({sup 99m}Tc), the product of radioactive decay of molybdenum-99 ( Mo), is one of the most widely used radioisotope in nuclear medicine, covering approximately 80% of all radiodiagnosis procedures in the world. Nowadays, Brazil requires an amount of about 450 Ci of {sup 99}Mo per week. Due to the crisis and the shortage of {sup 99}Mo supply chain that has been observed on the world since 2008, IPEN/CNEN-SP decided to develop a project to produce {sup 99}Mo through fission of uranium-235. The objective of this dissertation was the development of neutronic and thermal-hydraulic calculations to evaluate the operational safety of a device for {sup 99}Mo production to be irradiated in the IEA-Rl reactor core at 5 MW. In this device will be placed ten targets of UAl{sub x}-Al dispersion fuel with low enriched uranium (LEU) and density of 2.889 gU/cm{sup 3}. For the neutronic calculations were utilized the computer codes HAMMER-TECHNION and CITATION and the maximum temperatures reached in the targets were calculated with the code MTRCR-IEA-R1. The analysis demonstrated that the device irradiation will occur without adverse consequences to the operation of the reactor. The total amount of {sup 99}Mo was calculated with the program SCALE and considering that the time needed for the chemical processing and recovering of the {sup 99}Mo will be five days after the irradiation, we have that the {sup 99}Mo activity available for distribution will be 176 Ci for 3 days of irradiation, 236 Ci for 5 days of irradiation and 272 Ci for 7 days of targets irradiation. (author)'.

  7. Group IB Organometallic Chemistry XXXI. Synthesis and characterization of tetranuclear Me2N- and Me2NCH2-substituted diarylpropenylcopper-copper anion compounds (Vi2Cu4X2) containing bridging propenyl ligands. Isolation of a thermally stable mixed diarylpropenyl/arylcopper compound (Vi2Cu4Ar2)

    NARCIS (Netherlands)

    Koten, G. van; Hoedt, R.W.M. ten; Noltes, J.G.

    1979-01-01

    Thermally stable 1, 2-diarylpropenylcopper compounds (ViCu{2}X){n} (Vi = (2-Me{2}NC{6}H{4})C@?C(Me)(C{6}H{4}Me-4), X = Br (n = 2) or OTf2OTf = trifluoromethanesulphonate = triflate. and Vi = (2-Me{2}NCH{2}C{6}H{4})C@?C(Me)(C{6}H{4}Me-4), X = Br (n = 2)) have been prepared by reaction of

  8. In situ synthesis and study of morphology and thermal properties of polyamide 6 nanocomposites reinforced with different layered compounds; Sintese in situ e estudo da morfologia e propriedades termicas de nanocompositos de poliamida 6 reforcados com diferentes compostos lamelares

    Energy Technology Data Exchange (ETDEWEB)

    Botan, Rodrigo; Sartor, Sabrina de B.; Moraes, Samara B. de; Lona, Liliane M.F., E-mail: botan.03@gmail.com [Universidade Estadual de Campinas (FEQ/UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia Quimica

    2015-07-01

    Presently the research and development of new polymer nanocomposites is a field of large interest and importance to the scientific and technological community. For the development and improvement in synthesis and properties of new nanocomposites, different reinforcement types have been explored. Thus, this work studies the in situ synthesis and, morphological and thermal characterization of new polyamide 6 (PA6) nanocomposites reinforced with two different types of layered compounds: layered double hydroxide (LDH) and layered hydroxide salt (LHS). These new synthesized nanocomposites were characterized by x-ray diffraction (XRD), infrared spectroscopy by Fourier transform (FTIR) and thermogravimetric analysis (TGA). The results demonstrate that the new nanocomposites showed strong evidence of exfoliated morphology with improvement in their thermal properties compared with the neat PA6. (author)

  9. Group ib organometallic chemistry. XXXIV. Thermal behaviour and chemical reactivity of tetranuclear Me2N-substituted diarypropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds

    NARCIS (Netherlands)

    Hoedt, R.W.M. ten; Koten, G. van; Noltes, J.G.

    1980-01-01

    Thermal decomposition of configurationally pure 1,2-diarylpropenylcopper compounds Z-Vi2CU4Br2 and Z-Vi2Cu4R2 [Vi = (2-Me2NC6H4)C=C(Me)-(C6H4Me-4), R = 2-Me2NC6H4 or 4-MeC6H4CC] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were formed on thermolysis of (Z-ViCu2OTf)η

  10. Phase 0: goal study for the technical and economic evaluation of the Compound Parabolic Concentrator (CPC) concept applied to solar thermal and photovoltaic collectors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1975-06-01

    This report presents the results of a quick, six-week technical and economic evaluation of the compound parabolic concentrator (CPC) solar collector. The purpose of this effort was to provide an initial phase of a goals study that is directed toward recommending relative priorities for development of the compound parabolic concentrator concept. The findings of this study are of a very preliminary nature. Conclusions based on study findings at this depth should be considered preliminary and subject to revision and review in later phases.

  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. Evaluation of the stability of a mixture of volatile organic compounds on sorbents for the determination of emissions from indoor materials and products using thermal desorption/gas chromatography/mass spectrometry.

    Science.gov (United States)

    Brown, Veronica M; Crump, Derrick R; Plant, Neil T; Pengelly, Ian

    2014-07-11

    The standard method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air (ISO 16000-6:2011) specifies sampling onto the sorbent Tenax TA followed by analysis using thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). The informative Annex D to the standard suggests the use of multi-sorbent samplers to extend the volatility range of compounds which can be determined. The aim of this study was to investigate the storage performance of Tenax TA and two multi-sorbent tubes loaded with a mixture of nine VOCs of relevance for material emissions testing. The sorbent combinations tested were quartz wool/Tenax TA/Carbograph™ 5TD and quartz wool/Tenax TA/Carbopack™ X. A range of loading levels, loading conditions (humidities and air volume), storage times (1-4 weeks) and storage conditions (refrigerated and ambient) were investigated. Longer term storage trials (up to 1 year) were conducted with Tenax TA tubes to evaluate the stability of tubes used for proficiency testing (PT) of material emissions analyses. The storage performance of the multi-sorbent tubes tested was found to be equal to that for Tenax TA, with recoveries after 4 weeks storage of within about 10% of the amounts loaded. No consistent differences in recoveries were found for the different loading or storage conditions. The longer term storage trials also showed good recovery for these compounds, although two other compounds, hexanal and BHT, were found to be unstable when stored on Tenax TA. The results of this study provide confidence in the stability of nine analytes for up to 4 weeks on two multi-sorbent tubes for material emissions testing and the same compounds loaded on Tenax TA sorbent for a recently introduced PT scheme for material emissions testing. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Interfacial Characterizations of a Nickel-Phosphorus Layer Electrolessly Deposited on a Silane Compound-Modified Silicon Wafer Under Thermal Annealing

    Science.gov (United States)

    Lai, Kuei-Chang; Wu, Pei-Yu; Chen, Chih-Ming; Wei, Tzu-Chien; Wu, Chung-Han; Feng, Shien-Ping

    2016-10-01

    Front-side metallization of a Si wafer was carried out using electroless deposition of nickel-phosphorus (Ni-P) catalyzed by polyvinylpyrrolidone-capped palladium nanoclusters (PVP-nPd). A 3-[2-(2-Aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS) layer was covalently bonded on the Si surface as bridge linker to the Pd cores of PVP-nPd clusters for improving adhesion between the Ni-P layer and the Si surface. To investigate the effects of an interfacial ETAS layer on the Ni silicide formation at the Ni-P/Si contact, the Ni-P-coated Si samples were thermally annealed via rapid thermal annealing (RTA) from 500°C to 900°C for 2 min. To compare with the ETAS sample, the sputtered Ni layer on Si and electroless Ni-P layer on ion-Pd-catalyzed Si (both are standard processes) were also investigated. The microstructural characterizations for the Ni-P or Ni layer deposited on the Si wafer were performed using x-ray diffractometer, scanning electron microscopy, and transmission electron microscopy. Our results showed that the ETAS layer acted as a barrier to slow the atomic diffusion of Ni toward the Si side. Although the formation of Ni silicides required a higher annealing temperature, the adhesion strength and contact resistivity measurements of annealed Ni-P/Si contacts showed satisfactory results, which were essential to the device performance and reliability during thermal annealing.

  14. The effect of antioxidant concentration of N-isopropyl-N-phenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline and mixing time of physical properties, thermal properties, mechanical properties and microstructure on natural rubber compound

    Science.gov (United States)

    Budiarto

    2017-03-01

    Study the influence of high concentrations of antioxidants N-isopropyl-N-phenyl-p-phenylenediamine (IPPD) and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and the mixing time of the vulcanization physical properties, thermal properties, mechanical properties and structure micro on natural rubber compound has been done. The purpose of this study is to compare the effect of anti-oxidants types IPPD and TMQ and mixing time of vulcanization of the physical properties, mechanical properties, microstructure and elemental composition of the synthesis of natural rubber compound. Processes of vulcanization with variations in the concentration of antioxidant IPPD and TMQ: 2, 3, and 4 grams and mixing time: 20, 30, and 40 minutes. Analysis characterization of physical properties and mechanical properties of natural rubber compound showed that the maturity value 0,499Nm (TMQ) and 0.489 Nm (IPPD), Mooney viscosity value of 26.7 (TMQ) and 20.8 (IPPD), the value of the elongation at break 583.75 % (IPPD), and 552.63% (TMQ) as well as the value of tensile strength of 28.108 M.Pa (TMQ), and 27.986 M.Pa (IPPD). Analysis of thermal properties of natural rubber compound antioxidant IPPD with DTA shows there are three endothermic peak on the curve that is temperature 405°C, 550°C and 660°C and tested by TGA showed that the curve of the total reduction in the sample are 81.745% and compound rubber antioxidant TMQ with the analysis of DTA also contained 3 endothermic peak at a temperature 397,21°C, 514,02°C, and 610,27°C and TGA analysis shows the curve of the total sample of 82.356% reduction. Gsi fun group analysis rubber-antioxidant compound IPPD / TMQ with FTIR spectrophotometer shows some typical infrared absorption peak at the wave number (1 / λ) 833-895 cm-1 for cluster / CH bonds, 1,313 cm-1 for group / single bond Si-O, 1368 cm-1 to g ugus / single bond CC, 1507 cm-1, for cluster / bond C = C, 1665 cm-1For cluster / bond-C = O, 2128 cm-1 is the group / bond CN single, 3371

  15. Structural characterization, vibrational spectroscopy accomplished with DFT calculation, thermal and dielectric behaviors in a new organic-inorganic tertrapropylammonium aquapentachlorostannate dihydrate compound

    Energy Technology Data Exchange (ETDEWEB)

    Hajlaoui, Sondes, E-mail: hajlaouisondes@yahoo.fr [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia); Chaabane, Iskandar [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia); Lhoste, Jérôme; Bulou, Alain [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et Matériaux du Mans (IMMM), Avenue Olivier Messiaen, 72085, Le Mans, Cedex 9 (France); Guidara, Kamel [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia)

    2016-09-15

    In this work a novel compound tertrapropylammonium aquapentachlorostannate dihydrate was synthesized and characterized by; single crystal X-ray diffraction, vibrational spectroscopy, differential scanning calorimetric and dielectric measurement. The crystal structure refinement at room temperature reveled that this later belongs to the monoclinic compound with P121/c1 space group with the following unit cell parameters a = 8.2699(3) Å, b = 12.4665(4) Å, c = 22.3341(7) Å and β = 92.94(0)°. The crystal arrangement can be described by stacked organic-inorganic layers in the c direction with two independent water molecules placed between each two layers. The detailed interpretations of the vibrational properties of the studied compound were performed using density functional theory (DFT) with the B3LYP/LanL2DZ basis set, and has enabled us to make the detailed assignments by comparative study of the experimental and calculated Raman and IR spectra. The differential scanning calorimetry (DSC) measurement disclosed two anomalies in the temperature range 356–376 (T{sub 1}) K and at 393 K (T{sub 2}) characterized by the dehydration of the sample and probably a reconstruction of a new structure after T{sub 2} transition. The temperature dependences of dielectric permittivity show a relaxation process around T{sub 2} anomaly indicating the occurrence of the disorder at high temperature. The dependence of the exponent m(T) on temperature, extracted from the straight lines of log(ε″) with log (ω), suggests that the correlated barrier hopping is the appropriate model for the conduction mechanism. - Highlights: • The single-crystal X-ray diffraction has been performed. • The assignments of the vibration modes based on DFT were reported and discussed. • Differential scanning calorimetric reveals the presence of two endothermic peaks. • The electric permittivity was studied using the impedance measurements. • The CBH is the appropriate model for the conduction

  16. Enhanced Anti-Ultraviolet and Thermal Stability of a Pesticide via Modification of a Volatile Organic Compound (VOC-Free Vinyl-Silsesquioxane in Desert Areas

    Directory of Open Access Journals (Sweden)

    Derong Lin

    2016-08-01

    Full Text Available Due to the effect of severe environmental conditions, such as intense heat, blowing sand, and ultraviolet light, conventional pesticide applications have repeatedly failed to adequately control mosquito and sandfly populations in desert areas. In this study, a vinyl silsesquioxane (VS was added to a pesticide (citral to enhance residual, thermal and anti-ultraviolet properties via three double-bond reactions in the presence of an initiator: (1 the connection of VS and citral, (2 a radical self-polymerization of VS and (3 a radical self-polymerization of citral. VS-citral, the expected and main product of the copolymerization of VS and citral, was characterized using standard spectrum techniques. The molecular consequences of the free radical polymerization were analyzed by MALDITOF spectrometry. Anti-ultraviolet and thermal stability properties of the VS-citral system were tested using scanning spectrophotometry (SSP and thermogravimetric analysis (TGA. The repellency of VS-citral decreased over time, from 97.63% at 0 h to 72.98% at 1 h and 60.0% at 2 h, as did the repellency of citral, from 89.56% at 0 h to 62.73% at 1 h and 50.95% at 2 h.

  17. Influence of heating time and metal ions on the amount of free fatty acids and formation rates of selected carbonyl compounds during the thermal oxidation of canola oil.

    Science.gov (United States)

    Bastos, Luciane Conceição Silva; Pereira, Pedro Afonso de Paula

    2010-12-22

    Canola oil was heated continuously for 8 h at a typical frying temperature (180 °C) in the presence of various concentrations of the metal ions Fe(III), Cu(II), and Al(III) (9.2, 27.5, and 46.0 μg L(-1) of oil) to evaluate changes occurring in the amount of free fatty acids, expressed as acidity index, and in the formation rates of aldehydes. The aldehydes were collected and derivatized in silica cartridges functionalized with C18 and impregnated with an acid solution of 2,4-dinitrophenylhydrazine, after which they were eluted with acetonitrile and analyzed by LC-DAD-MS. Among the substances emitted, the following were identified and quantified: formaldehyde, acetaldehyde, acrolein, propanal, butanal, hexanal, (E)-2-heptenal, and octanal. During heating of the oil, the compounds presenting the highest mean formation rates were acrolein, hexanal, and acetaldehyde. In the study of the metal ions, the addition of ions to the samples generally led to a corresponding increase in the formation rates of the eight substances. The compounds showing the highest relative increases in formation rates were formaldehyde, acetaldehyde, propanal, and heptenal. In terms of catalytic effect, copper proved to be the most efficient in promoting increased formation rates, followed by iron and aluminum.

  18. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs).

    Science.gov (United States)

    Kang, Seok-Won; Fragala, Joe; Banerjee, Debjyoti

    2015-08-31

    Bi-layer (Au-Si₃N₄) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current.

  19. Possible Phonon Density of States of High-Temperature Phase Structure of the Negative Thermal Expansion Compound ZrW2O8

    Science.gov (United States)

    Yamamura, Yasuhisa; Saito, Kazuya

    2007-12-01

    To study the phonon properties of β-ZrW2O8 showing the negative thermal expansion (NTE), the heat capacities of Zr1-xMxW2O8-y (M = Sc, Lu; x = 0.02, 0.04) at low temperatures were measured and analyzed. The analysis presents the effective phonon density of states (DOS) of β-ZrW2O8, showing a rounded form around 5 meV. The rounded phonon DOS of β-ZrW2O8 is in marked contrast to that of the low-temperature phase of ZrW2O8, and their distinction is consistent with the difference in NTE nature between two structures.

  20. Gaseous byproducts from high-temperature thermal conversion elemental analysis of nitrogen- and sulfur-bearing compounds with considerations for δ2H and δ18O analyses.

    Science.gov (United States)

    Hunsinger, Glendon B; Tipple, Christopher A; Stern, Libby A

    2013-07-30

    High-temperature, conversion-reduction (HTC) systems convert hydrogen and oxygen in materials into H2 and CO for δ(2)H and δ(18)O measurements by isotope ratio mass spectrometry. HTC of nitrogen- and sulfur-bearing materials produces unintended byproduct gases that could affect isotope analyses by: (1) allowing isotope exchange reactions downstream of the HTC reactor, (2) creating isobaric or co-elution interferences, and (3) causing deterioration of the chromatography. This study characterizes these HTC byproducts. A HTC system (ThermoFinnigan TC/EA) was directly connected to a gas chromatograph/quadrupole mass spectrometer in scan mode (m/z 8 to 88) to identify the volatile products generated by HTC at conversion temperatures of 1350 °C and 1450 °C for a range of nitrogen- and sulfur-bearing solids [keratin powder, horse hair, caffeine, ammonium nitrate, potassium nitrate, ammonium sulfate, urea, and three nitrated organic explosives (PETN, RDX, and TNT)]. The prominent HTC byproduct gases include carbon dioxide, hydrogen cyanide, methane, acetylene, and water for all nitrogen-bearing compounds, as well as carbon disulfide, carbonyl sulfide, and hydrogen sulfide for sulfur-bearing compounds. The 1450 °C reactor temperature reduced the abundance of most byproduct gases, but increased the significant byproduct, hydrogen cyanide. Inclusion of a post-reactor chemical trap containing Ascarite II and Sicapent, in series, eliminated the majority of byproducts. This study identified numerous gaseous HTC byproducts. The potential adverse effects of these gases on isotope ratio analyses are unknown but may be mitigated by higher HTC reactor temperatures and purifying the products with a purge-and-trap system or with chemical traps. Published in 2013. This article is a U.S. Government work and is in the public domain in the USA.

  1. Synthesis, characterization and a thermal (TG-DSC) study of gadolinium and lutetium methanesulfonate coordination compounds with pyridine-N-oxide and 2-, 3- and 4-picoline-N-oxides

    OpenAIRE

    MARIADE F. V. DEMOURA; JIVALDO DO R. MATOS; ROBSON F. DE FARIAS

    2005-01-01

    The synthesis, characterization and a thermal (TG and DSC) study of the coordination compounds Gd(MS)3·(py-NO)2, Gd(MS)3·(2-picNO)2, Gd(MS)3·(3-picNO)2, Gd(MS)3·(4-picNO)2, Lu(MS)3·(py-NO)2·2H2O, Lu(MS)3·(2-picNO)1.5·H2O, Lu(MS)3·(3-picNO) and Lu(MS)3·(4-picNO)2 are reported (MS = methanesulfonate, py-NO = pyridine-N-oxide, 2-picNO, 3-picNo and 4-picNO are 2-, 3- and 4-picoline-N-oxides, respectively). The observed thermal stability trend is: 2-picNO < py-NO < 4-picNO < 3-picNO for Gd and 2-p...

  2. The Effect of Size and Crumb Rubber Composition as a Filler with Compatibilizer Pp-G-Ma in Polypropylene Blends and Sir-20 Compound on Mechanical and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Erna Frida

    2013-04-01

    Full Text Available Having been researched the development of thermoplastic elastomer material of polypropylene and natural rubber SIR-20 compound with Crumb Rubber as the filler. Reinforced polypropylene with size 60 mesh with 1 mm, and the composition of the Crumb rubber (30, 40, and 50 wt%. Observed mechanical properties are tensile strength, fracture elongation, Young's modulus, tear strength and impact strength. Thermal properties are analyzed by DSC and DTA/TGA. It is acquired that for the size of 60 mesh crumb rubber tensile strength, fracture elongation, Young’s modulus, tear strength and impact strength are bigger than 1mm size. The addition of 60 mesh crumb rubber increases but it decreases by adding of 50 weight%. While for crumb rubber 1 mm tensile strength, fracture elongation, tear strength and impact strength decreas. Based on analysis of DSC that the addition of crumb rubber does not make a difference boiling point significantly between samples containing crumb rubber and polypropylene Analysis TGA/DTA to an increase in enthalpy and decomposition temperature with the addition of crumb rubber used and thermal stability.

  3. The influence of the relative thermal expansion and electric permittivity on phase transitions in the perovskite-type bidimensional layered NH3(CH2)3NH3CdBr4 compound

    Science.gov (United States)

    Staśkiewicz, Beata; Staśkiewicz, Anna

    2017-07-01

    Hydrothermal method has been used to synthesized the layered hybrid compound NH3(CH2)3NH3CdBr4 of perovskite architecture. Structural, dielectric and dilatometric properties of the compound have been analyzed. Negative thermal expansion (NTE) effect in the direction perpendicular to the perovskite plane as well as an unusual phase sequence have been reported based on X-ray diffraction analysis. Electric permittivity measurements evidenced the phase transitions at Tc1=326/328 K and Tc2=368/369 K. Relative linear expansion measurements almost confirmed these temperatures of phase transitions. Anomalies of electric permittivity and expansion behavior connected with the phase transitions are detected at practically the same temperatures as those observed earlier in differential scanning calorimetry (DSC), infrared (IR), far infrared (FIR) and Raman spectroscopy studies. Mechanism of the phase transitions is explained. Relative linear expansion study was prototype to estimate critical exponent value β for continuous phase transition at Tc1. It has been inferred that there is a strong interplay between the distortion of the inorganic network, those hydrogen bonds and the intermolecular interactions of the organic component.

  4. Compound Semiconductor Radiation Detectors

    CERN Document Server

    Owens, Alan

    2012-01-01

    Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

  5. Studies of behavior of the fuel compound based on the U-Zr micro-heterogeneous quasialloy during cyclic thermal tests

    Science.gov (United States)

    Zaytsev, D. A.; Repnikov, V. M.; Soldatkin, D. M.; Solntsev, V. A.

    2017-11-01

    This paper provides the description of temperature cycle testing of U-Zr heterogeneous fuel composition. The composition is essentially a niobium-doped zirconium matrix with metallic uranium filaments evenly distributed over the cross section. The test samples 150 mm long had been fabricated using a fiber-filament technology. The samples were essentially two-bladed spiral mandrel fuel elements parts. In the course of experiments the following temperatures were applied: 350, 675, 780 and 1140 °C with total exposure periods equal to 200, 30, 30 and 6 hours respectively. The fuel element samples underwent post-exposure material science examination including: geometry measurements, metallographic analysis, X-ray phase analysis and electron-microscopic analysis as well as micro-hardness measurement. It has been found that no significant thermal swelling of the samples occurs throughout the whole temperature range from 350 °C up to 1140 °C. The paper presents the structural changes and redistribution of the fuel component over the fuel element cross section with rising temperature.

  6. Measurement of anharmonicity of phonons in the negative thermal expansion compound Zn(CN)2 by high pressure inelastic neutron scattering

    Science.gov (United States)

    Mittal, R.; Chaplot, S. L.; Schober, H.

    2009-11-01

    Zn(CN)2 is known to have an isotropic negative thermal expansion (NTE) coefficient (about -51×10-6 K-1) over 10-370 K that is twice as large as that of ZrW2O8. We have measured the pressure dependence of the phonon spectra up to 30 meV from a polycrystalline sample of Zn(CN)2 at pressures of 0, 0.3, 1.9, and 2.8 kbar at temperatures of 165 and 225 K. The measurements enabled us to estimate the energy dependence of the ratios Γi/B (Γi are Grüneisen parameters as a function of phonon energy Ei at ambient pressure and B is the bulk modulus), which reflect the anharmonicity of phonons. We conclude that the phonon modes of low energy below 15 meV play an important role in the understanding of the NTE behavior in Zn(CN)2 and the measured anharmonicity can quantitatively explain the NTE.

  7. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs

    Directory of Open Access Journals (Sweden)

    Seok-Won Kang

    2015-08-01

    Full Text Available Bi-layer (Au-Si3N4 microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current.

  8. Features of magnetic and thermal properties of R(Co{sub 1−x}Fe{sub x}){sub 2} (x≤0.16) quasibinary compounds with R=Dy, Ho, Er

    Energy Technology Data Exchange (ETDEWEB)

    Anikin, Maksim; Tarasov, Evgeniy; Kudrevatykh, Nikolay [Institute of Natural Sciences, Ural Federal University, Ekaterinburg 620002 (Russian Federation); Inishev, Aleksander [Institute of Metal Physics, Ekaterinburg 620137 (Russian Federation); Semkin, Mikhail; Volegov, Aleksey; Zinin, Aleksander [Institute of Natural Sciences, Ural Federal University, Ekaterinburg 620002 (Russian Federation)

    2016-11-15

    In this work the results of measurements of high field susceptibility, paraprocess susceptibility and thermal properties of R(Co{sub 1−x}Fe{sub x}){sub 2} intermetallic compounds (R=Dy, Ho, Er and x=(0−0.16)) are presented (heat capacity and magnetocaloric effect (MCE)). A magnetic structure of the Ho(Co{sub 0.88}Fe{sub 0.12}){sub 2} at 293 K and 78 K was studied by neutron powder diffraction. Some peculiarities of a high-field susceptibility were revealed at low temperatures and around the Curie point (T{sub C}). In temperature range lower than T{sub C} by (100–150) K, magnetic contributions to a zero-field heat capacity were found. Studying MCE in wide temperatures range, the large change of the entropy magnetic contribution (∆S) was observed which correlates with ∆T phenomenon. In particular, for the Er(Co{sub 0.84}Fe{sub 0.16}){sub 2} compound the ∆S value at low temperatures is six times higher than that at Curie point. The possible reasons of such behavior were discussed. - Highlights: • Magnetic and magnetocaloric properties of R(Co–Fe){sub 2} compounds have been studied. • Fe introduction induces the disorientation effect in Ho-ions magnetic ordering. • Emergence of magnetic contribution to a heat capacity at temperatures less T{sub C}. • The existence of a broad maximum on a temperature dependence of the MCE. • Direct MCE measurements at magnetic field of (0–17.5) kOe have been performed.

  9. Assessment of organic compound exposures, thermal comfort parameters, and HVAC system-driven air exchange rates in public school portable classrooms in California

    Energy Technology Data Exchange (ETDEWEB)

    Shendell, Derek Garth [Univ. of California, Los Angeles, CA (United States)

    2003-01-01

    The prevalence of prefabricated, portable classrooms (portables, relocatables, RCs) has increased due to class size reduction initiatives and limited resources. Classroom mechanical wall-mount heating, ventilation, and air conditioning (HVAC) systems may function improperly or not be maintained; lower ventilation rates may impact indoor air and environmental quality (IEQ). Materials in portables may off-gas volatile organic compounds (VOCs), including formaldehyde, as a function of age, temperature, and humidity. For a pilot study, public K-12 schools located in or serving target areas within five Los Angeles County communities were identified. In two communities where school districts (SD) consented, 1-3 randomly selected portables, one newer and one older, and one main building control classroom from each participating school were included. Sampling was conducted over a five-day school week in the cooling and heating seasons, or repeated twice in the cooling season. Measurements included passive samplers for VOCs, formaldehyde and acetaldehyde, and air exchange rate (AER) calculation; indoor air temperature and humidity; technician walk-through surveys; an interview questionnaire above HVAC system operation and maintenance (O and M). For an intervention study evaluating advanced HVAC technologies in comparison to the common conventional technology, and materials for source reduction of VOCs, four RC were manufactured and located in pairs at two schools in two recruited Northern California SD in different climate zones. RCs were built with the two HVAC systems, cabinetry and conduit for monitoring equipment, and standard or advanced interior finish materials. Each RC was its own control in a case-crossover design--HVAC systems alternately operated for 1-2 week intervals in the 2001-02 school year, with IEQ monitoring including aldehyde and indoor air temperature and humidity data. Measured classroom AER were low, formaldehyde concentrations were below the state

  10. Concentration, ozone formation potential and source analysis of volatile organic compounds (VOCs) in a thermal power station centralized area: A study in Shuozhou, China.

    Science.gov (United States)

    Yan, Yulong; Peng, Lin; Li, Rumei; Li, Yinghui; Li, Lijuan; Bai, Huiling

    2017-04-01

    Volatile organic compounds (VOCs) from two sampling sites (HB and XB) in a power station centralized area, in Shuozhou city, China, were sampled by stainless steel canisters and measured by gas chromatography-mass selective detection/flame ionization detection (GC-MSD/FID) in the spring and autumn of 2014. The concentration of VOCs was higher in the autumn (HB, 96.87 μg/m3; XB, 58.94 μg/m3) than in the spring (HB, 41.49 μg/m3; XB, 43.46 μg/m3), as lower wind speed in the autumn could lead to pollutant accumulation, especially at HB, which is a new urban area surrounded by residential areas and a transportation hub. Alkanes were the dominant group at both HB and XB in both sampling periods, but the contribution of aromatic pollutants at HB in the autumn was much higher than that of the other alkanes (11.16-19.55%). Compared to other cities, BTEX pollution in Shuozhou was among the lowest levels in the world. Because of the high levels of aromatic pollutants, the ozone formation potential increased significantly at HB in the autumn. Using the ratio analyses to identify the age of the air masses and analyze the sources, the results showed that the atmospheric VOCs at XB were strongly influenced by the remote sources of coal combustion, while at HB in the spring and autumn were affected by the remote sources of coal combustion and local sources of vehicle emission, respectively. Source analysis conducted using the Positive Matrix Factorization (PMF) model at Shuozhou showed that coal combustion and vehicle emissions made the two largest contributions (29.98% and 21.25%, respectively) to atmospheric VOCs. With further economic restructuring, the influence of vehicle emissions on the air quality should become more significant, indicating that controlling vehicle emissions is key to reducing the air pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The crystal structure, electrostatic properties, and thermal vibrations of some hydrated spermine compounds using neutron and x-ray diffraction data

    Science.gov (United States)

    Cohen, Aina Elizabeth

    Spermine phosphate hexahydrate crystallizes in space group P21/a with unit cell dimensions a = 7.931(1) A, b = 23.158(5) A, c = 6.856(2) A, and b = 113.44(2)° at 125 K with unit cell contents ([C10H 30N4]2+4 4[HPO4] -2·12H2O). The packing of spermines and monohydrogen phosphates in this crystal structure has features which may be relevant to the binding of spermine to DNA. Another important structural feature is the presence of channels containing water that is H-bonded as in ice-Ih with disordered protons. The channels occur between sheets of spermine long chains and are also bordered by H-bonded monohydrogen phosphate chains. Using neutron diffraction data, the H-bonding scheme of these water chains proposed on the basis of an earlier X-ray study is now confirmed. Nuclear positions, anisotropic m.s. displacements, an overall scale factor, and two extinction parameters ( r and g) were refined using full-matrix least-squares giving values of R(Fo2) = 0.09, Rw(Fo 2) = 0.11 and S = 1.02. Thermal vibrational analysis revealed that the backbone of the spermine cation can be described as a single rigid segment with a substantial libration of 27 deg2 around the spermine molecular long axis. The charge density distribution in the crystal structure of spermine phosphate hexahydrate ([C10H30N4] +4 2[HPO4]-2·6H2O) has been determined from X-ray diffraction data MoKa at 125 K using 13,984 reflections with sin/l≤1. 51 A-1. Least-squares structure refinement assuming Stewart's rigid pseudoatom model (variables included electron populations for multipole terms extending to octapoles for C, N, O, and P and up to dipoles for H) gave R(F2) = 0.042, Rw(F2) = 0.071 and S = 1.06. The electron density and its Laplacian have been determined at the (3, -1) or bond-critical points. The crystal structure of spermine dihydrate (C10H26N 4·2H2O), or possibly sperminium dihydroxide, has been determined for the non-hydrogen atoms. Spermine dihydrate crystallizes in space group P1¯ with

  12. Evaluation of Concepts for Mulitiple Application Thermal Reactor for Irradiation eXperiments (MATRIX)

    Energy Technology Data Exchange (ETDEWEB)

    Pope, Michael A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gougar, Hans D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ryskamp, John M. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-09-01

    The Advanced Test Reactor (ATR) is a high power density test reactor specializing in fuel and materials irradiation. For more than 45 years, the ATR has provided irradiations of materials and fuels testing along with radioisotope production. Originally operated primarily in support of the Offcie of Naval Reactors (NR), the mission has gradually expanded to cater to other customers, such as the DOE Office of Nuclear Energy (NE), private industry, and universities. Unforeseen circumstances may lead to the decommissioning of ATR, thus leaving the U.S. Government without a large-scale materials irradiation capability to meet the needs of its nuclear energy and naval reactor missions. In anticipation of this possibility, work was performed under the Laboratory Directed Research and Development (LDRD) program to investigate test reactor concepts that could satisfy the current missions of the ATR along with an expanded set of secondary missions. This work can be viewed as an update to a project from the 1990’s called the Broad Application Test Reactor (BATR). In FY 2012, a survey of anticipated customer needs was performed, followed by analysis of the original BATR concepts with fuel changed to low-enriched uranium. Departing from these original BATR designs, four concepts were identified for further analysis in FY2013. The project informally adopted the acronym MATRIX (Multiple-Application Thermal Reactor for Irradiation eXperiments). This report discusses analysis of the four MATRIX concepts along with a number of variations on these main concepts. Designs were evaluated based on their satisfaction of anticipated customer requirements and the “Cylindrical” variant was selected for further analysis of options. This downselection should be considered preliminary and the backup alternatives should include the other three main designs. The baseline Cylindrical MATRIX design is expected to be capable of higher burnup than the ATR (or longer cycle length given a

  13. Phytochemical and Bioactive Potential of in vivo and in vitro Grown Plants of Centaurea ragusina L. - Detection of DNA/RNA Active Compounds in Plant Extracts via Thermal Denaturation and Circular Dichroism.

    Science.gov (United States)

    Vujčić, Valerija; Radić Brkanac, Sandra; Radojčić Redovniković, Ivana; Ivanković, Siniša; Stojković, Ranko; Žilić, Irena; Radić Stojković, Marijana

    2017-11-01

    The phytochemical composition and biological activity of non-volatile components of Centaurea ragusina L. has not been studied previously. Our aim was to evaluate the phytochemical and bioactive potential (including interactions with polynucleotides) of C. ragusina L. depending on the origin of plant material (in vivo - leaves from natural habitats, ex vitro - leaves from plants acclimated from culture media, in vitro - leaves and calli from plants grown in culture media) and polarity of solvents used in extract preparation (80 and 96% ethanol and water combinations or single solvents). The polyphenol composition was determined by spectrophotometric and HPLC analysis. Biological activity of extracts was evaluated by following methods: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods for antioxidative activity, 2,3,5-triphenyl tetrazolium chloride (TTC) microdilution method for antibacterial activity, crystal-violet test for cytotoxic activity and thermal denaturation (TD) and circular dichroism (CD) for DNA/RNA interactions. Conditions for the most efficient polyphenol extraction were determined: the 80% ethanol/water solvent system was the most suitable for callus and leaf ex vitro samples and 80 or 96% ethanol for leaf in vivo samples. Significantly higher levels of chlorogenic acid and naringenin were detected in callus tissue than in vivo plant. Ethanolic extracts exhibited the significant antibacterial activity against Staphylococcus aureus ATCC 25923. DNA/RNA active compounds in plant extracts were detected by TD and CD methods. Callus tissue and ex vitro leaves represent a valuable source of polyphenols as in vivo leaves. TD and CD can be applied for detection of DNA/RNA active compounds in extracts from natural resources. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  14. Highly trifluoromethylated platinum compounds.

    Science.gov (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil

    2011-07-11

    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. CHARACTERIZATION OF RUTIN-CYCLODEXTRIN INCLUSION COMPOUNDS

    Directory of Open Access Journals (Sweden)

    Andreia Corciovă

    2011-12-01

    Full Text Available The objectives of this study were to examine the potential of beta-cyclodextrin to improve the solubility of rutin and obtain inclusion compounds that were analyzed by different techniques: UV-Vis, IR spectroscopy, thermal analysis. The presence of β-cyclodextrin raises the content of rutin in water. The inclusion compounds were prepared by dry mixing, complexation in semisolid and liquid medium in 1:2 molar ratio rutin - β-cyclodextrin. The UV-Vis and IR analysis demonstrated the obtaining of inclusion compounds and the thermal analysis show that these compounds are more stable than the parent substance.

  16. Crystal growth, structural, spectral, thermal, linear and nonlinear optical characterization of a new organic nonlinear chiral compound: L-tryptophan-fumaric acid-water (1/1/1) suitable for laser frequency conversion

    Science.gov (United States)

    Peer Mohamed, M.; Jayaprakash, P.; Nageshwari, M.; Rathika Thaya Kumari, C.; Sangeetha, P.; Sudha, S.; Mani, G.; Lydia Caroline, M.

    2017-08-01

    A new organic active nonlinear optical crystal L-tryptophan fumaric acid water (1/1/1), (C15H17N2 O7. H2O)(LTFAW), consisting of zwitterion tryptophan molecule in conjunction with a fumaric acid molecule and a water molecule was grown by slow solvent evaporation technique from aqueous solution. The organic chromophore crystallizes from water in its zwitterions exhibiting tabular habit in monoclinic system with acentric space group C2 (Z = 4). The sharp peaks observed in Powder X-ray diffractogram depicts the crystalline nature. The presence of functional groups in the grown crystal was analyzed using FT-IR spectrum. The carbon and hydrogen environment in molecular structure was investigated using FT-NMR technique using deuterated DMSO solution. Ultraviolet-visible spectral analysis reveal that the crystal possess lower cut-off wavelength down to 275 nm, is a key factor to exhibit Second Harmonic Generation (SHG) signal. The direct optical band gap is evaluated to be 5.28 eV from the UV absorption profile. The evaluation of optical constants by employing UV-visible absorbance data such as, extinction coefficient, reflectance, refractive index, optical conductivity are supportive towards good performance as NLO devices. Temperature of decomposition was investigated using thermogravimetric analysis/differential thermal analysis techniques (TG/DTA). The luminescence profile exhibited two peaks (362 nm, 683 nm) due to the donation of protons from carboxylic group to amino group. The nonlinear optical behavior from the noncentrosymmetric crystal was observed by the generation of frequency doubled (2ω) optical radiation when subjected to pulsed Nd:YAG laser (1064 nm, 10 ns, 10 Hz) using Kurtz-Perry method. The variation of dielectric constant (εʹ) and dielectric loss (εʹʹ) vs. Log f for the title compound was analysed at a few selected temperatures and frequencies.

  17. Multipurpose Compound

    Science.gov (United States)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  18. Mesoionic Compounds

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 10. Mesoionic Compounds - An Unconventional Class of Aromatic Heterocycles. Bharati V Badami. General Article Volume 11 Issue 10 October 2006 pp 40-48. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. Mesoionic Compounds

    Indian Academy of Sciences (India)

    Sydnone, the representative mesoionic compound has been extensively studied because of its unusual structure, chemi- cal properties and synthetic utility. Sydnone is used as a versatile synthon in heterocyclic synthesis. This article gives a brief account of the comparative studies of the structural features of mesoionic ...

  20. Thermal decomposition of hemicelluloses

    OpenAIRE

    Werner, Kajsa; Pommer, Linda; Broström, Markus

    2014-01-01

    Decomposition modeling of biomass often uses commercially available xylan as model compound representing hemicelluloses, not taking in account the heterogeneous nature of that group of carbohydrates. In this study, the thermal decomposition behavior of seven different hemicelluloses (beta-glucan, arabinogalactan, arabinoxylan, galactomannan, glucomannan, xyloglucan, and xylan) were investigated in inert atmosphere using (i) thermogravimetric analysis coupled to Fourier transform infrared spec...

  1. Compound odontoma

    Directory of Open Access Journals (Sweden)

    Monica Yadav

    2012-01-01

    Full Text Available Odontomas have been extensively reported in the dental literature, and the term refers to tumors of odontogenic origin. Though the exact etiology is still unknown, the postulated causes include: local trauma, infection, inheritance and genetic mutation. The majority of the lesions are asymptomatic; however, may be accompanied with pain and swelling as secondary complaints in some cases. Here, we report a case of a compound odontome in a 14 year old patient.

  2. Reducing Contact Resistance Errors In Measuring Thermal ...

    African Journals Online (AJOL)

    Values of thermal conductivity (k) of glass beads, quartz sand, stone dust and clay were determined using a thermal probe with and without heat sink compounds (arctic silver grease (ASG) and white grease (WG)) at different water contents, bulk densities and particle sizes. The heat sink compounds (HSC) increased k at ...

  3. Synthesis, photophysical, electrochemical and thermal investigation ...

    Indian Academy of Sciences (India)

    studies revealed that the synthesized compounds have good thermal stability with 5% and 10% weight loss at ... from carbazole10 and fluoranthene20 emit either green ..... The obtained CIE are located in yellow−green region (see Supporting. Information). Table 2. Electrochemical and thermal data for compounds 2–4.

  4. Nuclear Thermal Rocket (NTR) Development Risk Communication

    Science.gov (United States)

    Kim, Tony

    2014-01-01

    nuclear radiation from Fukushima" which focus on mis-information and fear mongering. Nuclear power and NTR are powerful resources that can open many doors for future prosperity and capability. With great power comes great responsibility. Radiation and its effects need to be better understood, quantified, and communicated. A human mission to mars has its own risks of deep space radiation and is considered a considerable risk at 400 milli-Sieverts per year in deep space and 245 milli-Sieverts per year on the surface of Mars as measured by the Mars Curiosity mission. Although these quantities of ionizing radiation are within the astronaut career limit, it exceeds the yearly average amounts of ionizing radiation. Astronaut crews have experienced these levels of radiation before, but for durations shorter than a year, and a mission to Mars could possibly be 3 years in length. There is also evidence that people can comfortably handle higher levels of ionizing radiation where the radiation occurs naturally like Ramsar, Iran when people can experience 270 milli-Sieverts per year. A risk posture that the development, test, and flight of an NTR will meet opposition from groups who oppose nuclear energy must be likely and the impact can be sever to the effort. Active risk mitigation must be taken for an NTR full-scale development project. The NTR design must take into account safety for transport and off nominal conditions. Nuclear fuel element must consider containment of fission products and Low Enriched Uranium (LEU) that may meet less opposition should be considered for safety and security reasons. Even though testing was conducted on Rover/NERVA safely and successfully in the 60's with exhaust sent heavenward in to open air, modern testing of NTR must consider full containment and no release of ionizing radiation to the public and must meet the current requirement of no more than 0.1 milli-Sieverts per year to the public. 0.1 milli-Sieverts is equivalent to eating one banana or

  5. Two new supramolecular compounds induced by novel ...

    Indian Academy of Sciences (India)

    Compound 1 has a 2D polypseudorotaxane structure and compound 2 presents a 1D chain structure. Furthermore, the thermal gravimetric analysis (TGA),UV–Vis diffusereflectance spectra, the morphology and the photocatalytic performances were studied carefully. Remarkably, both 1 and 2 exhibited good photocatalytic ...

  6. Lattice anisotropy in uranium ternary compounds

    DEFF Research Database (Denmark)

    Maskova, S.; Adamska, A.M.; Havela, L.

    2012-01-01

    Several U-based intermetallic compounds (UCoGe, UNiGe with the TiNiSi structure type and UNiAl with the ZrNiAl structure type) and their hydrides were studied from the point of view of compressibility and thermal expansion. Confronted with existing data for the compounds with the ZrNiAl structure...

  7. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  8. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  9. Bismaleimide compounds

    Science.gov (United States)

    Adams, Johnnie E.; Jamieson, Donald R.

    1986-01-14

    Bismaleimides of the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, C1 or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  10. Reactive codoping of GaAlInP compound semiconductors

    Science.gov (United States)

    Hanna, Mark Cooper [Boulder, CO; Reedy, Robert [Golden, CO

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  11. EVALUATION OF THERMAL PROTECTIVE SYSTEMS FOR ADVANCED AEROSPACE VEHICLES. VOLUME II: APPENDICES.

    Science.gov (United States)

    AEROSPACE CRAFT, TABLES(DATA), GRAPHICS, OXIDES, BERYLLIUM, HAFNIUM COMPOUNDS, SPINEL, ZIRCONIUM COMPOUNDS, NITRIDES, CARBIDES, BORIDES , SILICIDES...GRAPHITE, NIOBIUM, MOLYBDENUM , TANTALUM, TUNGSTEN, THERMAL PROPERTIES, THERMAL PROPERTIES, SPECIFIC HEAT.

  12. Physical and mechanical properties of lamellar compounds of graphite

    OpenAIRE

    Костиков, Александр Анатольевич; Довгаль, Анна Николаевна; Черномаз, Владимир Николаевич; Кузнецов, Андрей Андреевич

    2013-01-01

    In this paper physical, mechanical and thermophysical properties of lamellar graphite compounds with various intercalants have been studied as a function of temperature and oxidants. The focus of the study was the influence of various factors on lamellar graphite compounds parameters, namely: elongation of samples, thermal expansion coefficient, thermal conductivity. The following factors have been considered: oxidant concentration in the synthesis of lamellar graphite compounds, the particle...

  13. Thermal comfort

    CSIR Research Space (South Africa)

    Osburn, L

    2010-01-01

    Full Text Available wider range of temperature limits, saving energy while still satisfying the majority of building occupants. It is also noted that thermal comfort varies significantly between individuals and it is generally not possible to provide a thermal environment...

  14. Hausa verbal compounds

    NARCIS (Netherlands)

    McIntyre, Joseph Anthony

    2006-01-01

    Verbal compounds abound in Hausa (a Chadic language). A very broad definition of Hausa verbal compounds (henceforth: VC) is “a compound with a verb”. Four types of verbal compound are analysed: V[erb]+X compounds, PAC+V compounds (a PAC is a pronoun complex indicating TAM), VCs with a ma prefix

  15. Synthesis, crystal structure determination, thermal and magnetic properties of the new Cu{sub 0.73}Ni{sub 0.27}(HSeO{sub 3}){sub 2} compound

    Energy Technology Data Exchange (ETDEWEB)

    Hentech, I., E-mail: hentechimen@yahoo.fr [Laboratoire des Sciences des Matériaux et de l' Environnement, Faculté des Sciences de Sfax, BP 1171, Université de Sfax, 3000 (Tunisia); CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France); Zehani, K. [CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France); Kabadou, A.; Ben Salah, A.; Loukil, M. [Laboratoire des Sciences des Matériaux et de l' Environnement, Faculté des Sciences de Sfax, BP 1171, Université de Sfax, 3000 (Tunisia); Bessais, L. [CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France)

    2017-01-15

    A novel three-dimensional Cu{sub 0.73}Ni{sub 0.27}(HSeO{sub 3}){sub 2} compound was prepared from an aqueous solution. This compound crystallizes in the monoclinic system with P2{sub 1}/n space group and with the following cell parameters: a=6.4379(3) Å; b=7.3555(3) Å; c=5.7522(3) Å; β=93.4341(1)°; V=271.90(2) Å{sup 3} and Z=2. The reported material has been structurally characterized by X-ray powder diffraction and confirmed by scanning electron microscope and energy dispersive spectroscopy (MEB/EDS) analysis. The copper/nickel atom is surrounded by an octahedron coordination of oxygen atoms from sex hydrogenoselenites anions. The presence of (HSeO{sub 3}){sup −} has been further confirmed by IR spectroscopy and this compound exhibits a phase transition at 356 K, this transition has been detected by differential scanning calorimetry and TG-DTA measurement. The magnetic property of this material was determined. The ferromagnetic ordering is further confirmed by the magnetic field dependence of the magnetization (Hysteresis loop) at 10 K. The substitution of Cu by Ni induces a ferro-paramagnetic transition at T=31 K. Field cooled (FC) and Zero field cooled (ZFC) magnetization measurements under an applied field of 100 Oe in the temperature range of 10–300 K were performed. These measurements have been resulted the blocking temperature (T{sub B}) at around 25 K. - Highlights: • A novel three-dimensional Cu{sub 0.73}Ni{sub 0.27}(HSeO{sub 3}){sub 2} compound was prepared from an aqueous solution. • Magnetic measurements reveal the occurrence of weak ferromagnetism at low temperature for this compound. • The substitution of Cu by Ni induces a ferro-paramagnetic transition at T=31 K.

  16. Six novel transition-metal phosphite compounds, with structure related to yavapaiite: Crystal structures and magnetic and thermal properties of A{sup I}[M{sup III}(HPO{sub 3}){sub 2}] (A=K, NH{sub 4}, Rb and M=V, Fe)

    Energy Technology Data Exchange (ETDEWEB)

    Hamchaoui, Farida [Laboratoire des Sciences des Materiaux, Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Alonzo, Veronique [Sciences Chimiques de Rennes, UMR6226, Ecole Nationale Superieure de Chimie de Rennes, CNRS, Avenue du General Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Universite Europeenne de Bretagne (France); Venegas-Yazigi, Diego [Facultad de Quimia y Biologia, Universitad de Santiago de Chile, USACH, Casilla, 40 Correo 33, Santiago (Chile); Rebbah, Houria [Laboratoire des Sciences des Materiaux, Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Le Fur, Eric, E-mail: eric.le-fur@ensc-rennes.fr [Sciences Chimiques de Rennes, UMR6226, Ecole Nationale Superieure de Chimie de Rennes, CNRS, Avenue du General Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Universite Europeenne de Bretagne (France)

    2013-02-15

    Six new transition metal(III) phosphites A{sup I}[V{sup III}(HPO{sub 3}){sub 2}], where A=K (1), NH{sub 4} (2) and Rb (3) and A{sup I}[Fe{sup III}(HPO{sub 3}){sub 2}] where A=K (4), NH{sub 4} (5) and Rb (6) have been synthesized under hydrothermal conditions and the solid-state structures were solved from single-crystal X-ray diffraction data. These compounds crystallize in the hexagonal system, space group P6{sub 3}mc (no. 186), with a=5.3294(2) A and c=12.3130(5) A for 1, a=5.3330(2) A and c=12.8760(4) A for 2, a=5.3459(2) A and c=12.6850(8) A for 3, a=5.3256(1) A and c=12.2362(3) A for 4, a=5.3229(2) A and c=12.8562(4) A for 5, a=5.3393(2) A and c=12.6913(5) A for 6, with Z=2 in the six phases. The crystal structures of these compounds are isotypic and exhibit a layered structure stacked along the c-axis with the A{sup +} cations located in the interlayer space. The [M{sup III}(HPO{sub 3}){sub 2}]{sup -} sheets are formed by MO{sub 6} octahedra interconnected by HPO{sub 3} tetrahedral phosphite oxoanions through sharing vertices. Thermal analysis shows a large range of stability for compounds containing potassium and rubidium cations with decomposition starting around 550 K for stable compounds and above 840 K for the most stable compounds leading in general to pyrophosphate compounds. Triangular nets of metallic centers are observed within the layers in which antiferromagnetic interactions are evidenced by magnetic susceptibility measurements suggesting magnetic frustration. - Graphical abstract: Six new transition metal(III) phosphites A{sup I}[M{sup III}(HPO{sub 3}){sub 2}], where A=K, NH{sub 4}, Rb and M=V, Fe, have been synthesized. The crystal structures of these compounds are isotypic and exhibit a lamellar structure related to Yavapaiite. The M(HPO{sub 3}){sub 2} layers separated by cationic species present the metallic centers in a triangular arrangement. Bulk antiferromagnetic behavior is observed for all the studied compounds. Highlights: Black

  17. Rubber compounding and processing

    CSIR Research Space (South Africa)

    John, MJ

    2014-06-01

    Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...

  18. Spectroscopic, thermal and biological studies of coordination ...

    Indian Academy of Sciences (India)

    , thermal and biological studies of coordination compounds of sulfasalazine drug: Mn(II), Hg(II), Cr(III), ZrO(II), VO(II) and Y(III) transition metal complexes. M G Abd El-Wahed M S Refat S M El-Megharbel. Thermal Studies Volume 32 Issue 2 ...

  19. Influence of time, surface-to-volume ratio, and heating process (continuous or intermittent) on the emission rates of selected carbonyl compounds during thermal oxidation of palm and soybean oils.

    Science.gov (United States)

    da Silva, Thalita Oliveira; Pereira, Pedro Afonso de Paula

    2008-05-14

    The aim of this work was to compare the emission rates of selected carbonyl compounds (CC) produced by palm and soybean oils when heated at 180 degrees C in the presence of air, through different time intervals and at different surface-to-volume ratios ( S/ V), in continuous and intermittent processes. The CC were collected and derivatized onto silica C18 cartridges impregnated with an acid 2,4-dinitrophenylhidrazine solution, followed by extraction with acetonitrile and analysis by HPLC-UV and, in some cases, HPLC-MS with electrospray ionization. Among the CC quantified, namely, acetaldehyde, acrolein, propanal, butanal, hexanal, 2-heptenal, and 2-octenal, acrolein was the main emission in both oils and all S/ V ratios, followed by hexanal and 2-heptenal. The soybean oil has presented greater emission rates of acrolein than palm oil. When different S/ V ratios used during the heating process of the oil were compared, the emission rates, in general, were directly related to them, although saturated and nonsaturated CC have had different behaviors toward oxidation reactions. During intermittent heating, there was a trend of increasing emission rates of saturated aldehydes, whereas the opposite was observed with unsaturated aldehydes, probably due to the reactivity of the double bond present in these compounds.

  20. Three coordination compounds based on benzene tetracarboxylate ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 8. Three coordination compounds based on benzene tetracarboxylate ligand: syntheses, structures, thermal behaviors and luminescence properties. YUNLONG WU CHANGKUN XIA JUN QIAN JIMIN XIE. REGULAR ARTICLE Volume 129 Issue 8 August ...

  1. Formation of Sodium cyclo-Triphosphate by the Thermal Reaction of Sodium Dihydrogenphosphate-Organic Nitrogen Compound Mixtures; Rinsan nisuiso natoriumu-yuki chisso kagobutsu kongokei no kanetsu ni yoru cyclo-sanrinsan natoriumu no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, Atsushi.; Kikui, Satoshi. [Yonago National College of Technology, Tottori (Japan). Department of Materials Science; Motooka, Itaru.; Nariai, Hiroyuki. [Kobe University, Hyogo (Japan). Department of Chemical Science and Engineering

    1998-11-10

    Mixtures of sodium dihydrogenphosphate (NaH{sub 2}PO{sub 4}) with biuret, cyanuric acid, or melamine were heated in a stream of nitrogen gas. Crystalline sodium polyphosphate of high-temperature type of Maddrell`s salt was produced at above 300 degree C in the NaH{sub 2}PO{sub 4}-cyanuric acid or NaH{sub 2}PO{sub 4}-melamine mixtures. Sodium cyclo-trihosphate was produced in the NaH{sub 2}PO{sub 3}-biuret mixture in a similar manner to the thermal reaction of NaH{sub 2}PO{sub 4}-urea mixture reported previously, which was considered to be responsible for the enhanced water-vapor pressure in samples caused by the the formation of a kind of (shell.) An increase in amount of biuret added was available for the formation of cyclo-triphosphate. (author)

  2. Formation of Sodium cyclo-Triphosphate by the Thermal Reaction of Sodium Dihydrogenphosphate-Organic Nitrogen Compound Mixtures. Rinsan nisuiso natoriumu-yuki chisso kagobutsu kongokei no kanetsu ni yoru cyclo-sanrinsan natoriumu no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, Atsushi.; Kikui, Satoshi. (Yonago National College of Technology, Tottori (Japan). Department of Materials Science); Motooka, Itaru.; Nariai, Hiroyuki. (Kobe University, Hyogo (Japan). Department of Chemical Science and Engineering)

    1998-11-10

    Mixtures of sodium dihydrogenphosphate (NaH[sub 2]PO[sub 4]) with biuret, cyanuric acid, or melamine were heated in a stream of nitrogen gas. Crystalline sodium polyphosphate of high-temperature type of Maddrell's salt was produced at above 300 degree C in the NaH[sub 2]PO[sub 4]-cyanuric acid or NaH[sub 2]PO[sub 4]-melamine mixtures. Sodium cyclo-trihosphate was produced in the NaH[sub 2]PO[sub 3]-biuret mixture in a similar manner to the thermal reaction of NaH[sub 2]PO[sub 4]-urea mixture reported previously, which was considered to be responsible for the enhanced water-vapor pressure in samples caused by the the formation of a kind of (shell.) An increase in amount of biuret added was available for the formation of cyclo-triphosphate. (author)

  3. Preparation and optical and electrical evaluation of bulk SiO{sub 2} sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, Maria Elena [Coordinacion de Ingenieria Mecatronica, Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786 Huixquilucan, Estado de Mexico (Mexico); Morales-Saavedra, Omar G. [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico)], E-mail: omar.morales@ccadet.unam.mx; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico); Ortiz Rebollo, Armando [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, IIM-UNAM, A.P. 70-360, Coyoacan, 04510 Mexico, D.F. (Mexico)

    2009-02-25

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E{sub g}) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO{sub 2} sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively.

  4. Synthesis, crystal structure, thermal analysis and dielectric properties of [(C{sub 4}H{sub 9}){sub 4}N]{sub 3}Bi{sub 2}Cl{sub 9} compound

    Energy Technology Data Exchange (ETDEWEB)

    Trigui, W., E-mail: walatrigui@yahoo.fr; Oueslati, A.; Chaabane, I.; Hlel, F.

    2015-07-15

    A new organic–inorganic tri-tetrabutylammonium nonachlorobibismuthate(III) compound was prepared. It was found to crystallize in the monoclinic system (P2{sub 1}/n space group) with the following lattice parameters: a=11.32(2) Å, b=22.30(3) Å, c=28.53(2) Å and β=96.52(0)°. The [Bi{sub 2}Cl{sub 9}]{sup 3−} anions are surrounded by six [(C{sub 4}H{sub 9})N]{sup +} cations, forming an octahedral configuration. These octahedra are sharing corners in order to provide the tri-dimensional network cohesion. The differential scanning calorimetry reveals four order-disorder reversible phase transitions located at 214, 238, 434 and 477 K. The Raman and infrared spectra confirm the presence of both cationic [(C{sub 4}H{sub 9})N]{sup +} and anionic [Bi{sub 2}Cl{sub 9}]{sup 3−} parts. The dielectric parameters, real and imaginary dielectric permittivity (ε′ and ε″), and dielectric loss tangent (tg δ), were measured in the frequency range of 209 kHz–5 MHz at different temperatures. The variations of dielectric dispersion (ε') and dielectric absorption (ε″) with frequency show a distribution of relaxation times, which is probably related to the change in the dynamical state of the [(C{sub 4}H{sub 9}){sub 4}N]{sup +} cations and the [Bi{sub 2}Cl{sub 9}]{sup 3−} anions. - Graphical abstract: Projection of the atomic arrangement of the [(C{sub 4}H{sub 9}){sub 4}N]{sub 3}Bi{sub 2}Cl{sub 9} compound along the b axis. - Highlights: • The structure of the (TBA){sub 3}Bi{sub 2}Cl{sub 9} compound was solved and reported. • The cristal belongs to the monoclinic system with P2{sub 1}/n space group. • DSC discloses four order–disorder reversible phases transitions. • The temperature-dependent permittivity ε' and ε″ has been investigated.

  5. Re-evaluation of effective carbon number (ECN) approach to predict response factors of 'compounds lacking authentic standards or surrogates' (CLASS) by thermal desorption analysis with GC-MS.

    Science.gov (United States)

    Szulejko, Jan E; Kim, Ki-Hyun

    2014-12-03

    In our recent study, we experimentally demonstrated the feasibility of an effective carbon number (ECN) approach for the prediction of the response factor (RF) values of 'compounds lacking authentic standards or surrogates' (CLASS) using a certified 54-mix containing 38 halogenated analytes as a pseudo-unknown. Although our recent analysis performed well in terms of RF predictive power for a 25-component learning set (for both Q-MS and TOF-MS detection), large physically unrealistic negative ECN and carbon number equivalent (CNE) values were noted for TOF-MS detection, e.g., ECN (acetic acid)=-16.96. Hence, to further improve the ECN-based quantitation procedure of CLASS, we re-challenged RF vs. ECN linear regression analysis with additional descriptors (i.e., Cl, Br, CC, and a group ECN offset (Ok)) using the 1-point RF values. With an Ok, all compound classes, e.g., halo-alkanes/-alkenes and aromatics can now be fitted to yield consistently positive set of ECN values for most analytes (e.g., 3 outliers out of 29, Q-MS detection). In this way, we were able to further refine our approach so that the absolute percentage difference (PD)±standard deviation (SD) between mass detected vs. mass loaded is reduced from 39.0±34.1% (previous work) to 13.1±12.0% (this work) for 29 C1C4 halocarbons (Q-MS detector). Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Time-resolved X-ray absorption spectroscopy for the study of solid state reactions: synthesis of nanocrystalline barium titanate and thermal decomposition of ammonium hexachlorometallate compounds; Zeitaufgeloeste Roentgenabsorptionspektroskopie zur Untersuchung von Festkoerperreaktionen: Synthese von nanokristallinem Bariumtitanat und thermische Zersetzung von Ammoniumhexachlorometallat-Verbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Rumpf, H.

    2001-07-01

    This report presents investigations on the mechanism of two different types of solid-state reactions: At first, barium titanate nanopowders were prepared through a combined polymerization and pyrolysis of a metallo-organic precursor. The mean particle size d{sub m} could be adjusted by choosing appropriate reaction temperatures and tempering atmospheres. In the present in situ study of this particular solid-phase reaction, X-ray absorption near edge structure (XANES) spectroscopy at the Ti K and Ba L{sub 3}-edges was applied in the preparation route of BaTiO{sub 3} nanopowders. A pronounced distortion of the lattice symmetry was found to occur in very fine BaTiO{sub 3} nanopowders (d{sub m} < 20 nm). Secondly, in situ XANES investigations were carried out at the Cl K, Pd L{sub 3}, Rh L{sub 3}, and Pt L{sub 3}-edges to study the mechanism of the thermal decomposition of ammonium hexachlorometallates. The results exceed structural information obtained by in situ X-ray diffraction methods and thermal analysis. Feff8 multiple scattering simulations have been carried out to disclose new intermediate phases of unknown reference compounds. (orig.)

  7. Morphology, mechanical, cross-linking, thermal, and tribological properties of nitrile and hydrogenated nitrile rubber/multi-walled carbon nanotubes composites prepared by melt compounding: The effect of acrylonitrile content and hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Likozar, Blaz, E-mail: blaz.likozar@fkkt.uni-lj.si [Polymer Competence Center Leoben GmbH, Montanuniversitaet Leoben, Roseggerstrasse 12, A-8700 Leoben (Austria); Major, Zoltan, E-mail: zoltan.major@jku.at [Polymer Competence Center Leoben GmbH, Montanuniversitaet Leoben, Roseggerstrasse 12, A-8700 Leoben (Austria)

    2010-11-01

    The purpose of this work was to prepare nanocomposites by mixing multi-walled carbon nanotubes (MWCNT) with nitrile and hydrogenated nitrile elastomers (NBR and HNBR). Utilization of transmission electronic microscopy (TEM), scanning electron microscopy (SEM), and small- and wide-angle X-ray scattering techniques (SAXS and WAXS) for advanced morphology observation of conducting filler-reinforced nitrile and hydrogenated nitrile rubber composites is reported. Principal results were increases in hardness (maximally 97 Shore, type A), elastic modulus (maximally 981 MPa), tensile strength (maximally 27.7 MPa), elongation at break (maximally 216%), cross-link density (maximally 7.94 x 10{sup 28} m{sup -3}), density (maximally 1.16 g cm{sup -3}), and tear strength (11.2 kN m{sup -1}), which were clearly visible at particular acrylonitrile contents both for unhydrogenated and hydrogenated polymers due to enhanced distribution of carbon nanotubes (CNT) and their aggregated particles in the applied rubber matrix. Conclusion was that multi-walled carbon nanotubes improved the performance of nitrile and hydrogenated nitrile rubber nanocomposites prepared by melt compounding.

  8. Morphology, mechanical, cross-linking, thermal, and tribological properties of nitrile and hydrogenated nitrile rubber/multi-walled carbon nanotubes composites prepared by melt compounding: The effect of acrylonitrile content and hydrogenation

    Science.gov (United States)

    Likozar, Blaž; Major, Zoltan

    2010-11-01

    The purpose of this work was to prepare nanocomposites by mixing multi-walled carbon nanotubes (MWCNT) with nitrile and hydrogenated nitrile elastomers (NBR and HNBR). Utilization of transmission electronic microscopy (TEM), scanning electron microscopy (SEM), and small- and wide-angle X-ray scattering techniques (SAXS and WAXS) for advanced morphology observation of conducting filler-reinforced nitrile and hydrogenated nitrile rubber composites is reported. Principal results were increases in hardness (maximally 97 Shore, type A), elastic modulus (maximally 981 MPa), tensile strength (maximally 27.7 MPa), elongation at break (maximally 216%), cross-link density (maximally 7.94 × 1028 m-3), density (maximally 1.16 g cm-3), and tear strength (11.2 kN m-1), which were clearly visible at particular acrylonitrile contents both for unhydrogenated and hydrogenated polymers due to enhanced distribution of carbon nanotubes (CNT) and their aggregated particles in the applied rubber matrix. Conclusion was that multi-walled carbon nanotubes improved the performance of nitrile and hydrogenated nitrile rubber nanocomposites prepared by melt compounding.

  9. A Silsesquioxane Organically Modified with 4-Amino-5-(4-pyridyl-4H-1,2,4-triazole-3-thiol: Thermal Behavior and Its Electrochemical Detection of Sulfhydryl Compounds

    Directory of Open Access Journals (Sweden)

    D. R. Do Carmo

    2014-01-01

    Full Text Available The octakis(3-chloropropylsilsesquioxane (SS was organofunctionalized with 4-amino-5-4(pyridyl-4H-1,2,4-triazole-3-thiol. The product formed (SA was undergo another reactions in two steps, first with copper and so hexacyanoferrate (III to form CuHSA. The organofunctionalized silsesquioxane was characterized by the following techniques: scanning electron microscopy (SEM, Fourier transform infrared (FTIR, nuclear magnetic resonance (NMR in solid state, and thermogravimetric analysis in air and nitrogen atmosphere. The composite CuHSA was incorporated into a graphite paste electrode and the electrochemical behavior studies were conducted with cyclic voltammetry. The cyclic voltammogram of the modified graphite paste electrode with CuHSA showed one redox couple with formal potential Eθ′=0.75 V versus Ag/AgCl(sat (KCl 1.0 mol L−1; v = 20 mV s−1 attributed to the redox process Fe(II(CN6/Fe(III(CN6 of the binuclear complex formed. The redox couple presents an electrocatalytic response of sulfhydryl compounds such as n-acetylcysteine and l-cysteine. For determination of n-acetylcysteine and l-cysteine the modified graphite paste electrode showed a linear region in the concentration range of 2 to 20 mmol L−1. The modified electrode was chemically and electrochemically stable and showed good reproducibility.

  10. Effect of different drying techniques on the volatile compounds ...

    African Journals Online (AJOL)

    Purpose: To examine the volatile compounds, thermal stability and morphological characteristics of stevia (Stevia rebaudiana Bertoni) leaves after sun, oven and microwave drying. Methods: Gas chromatography-mass spectrometry with a spectral analysis manager was used to separate the volatile compounds. Dried stevia ...

  11. Heterogeneous photocatalytic reactions of sulfur aromatic compounds.

    Science.gov (United States)

    Samokhvalov, Alexander

    2011-11-18

    Sulfur aromatic compounds, such as mono-, di-, tri-, and tetraalkyl-substituted thiophene, benzothiophenes, dibenzothiophenes, are the molecular components of many fossils (petroleum, oil shale, tar sands, bitumen). Structural units of natural, cross-linked heteroaromatic polymers present in brown coals, turf, and soil are similar to those of sulfur aromatic compounds. Many sulfur aromatic compounds are found in the streams of petroleum refining and upgrading (naphthas, gas oils) and in the consumer products (gasoline, diesel, jet fuels, heating fuels). Besides fossils, the structural fragments of sulfur aromatic compounds are present in molecules of certain organic semiconductors, pesticides, small molecule drugs, and in certain biomolecules present in human body (pheomelanin pigments). Photocatalysis is the frontier area of physical chemistry that studies chemical reactions initiated by absorption of photons by photocatalysts, that is, upon electronic rather than thermal activation, under "green" ambient conditions. This review provides systematization and critical review of the fundamental chemical and physicochemical information on heterogeneous photocatalysis of sulfur aromatic compounds accumulated in the last 20-30 years. Specifically, the following topics are covered: physicochemical properties of sulfur aromatic compounds, major classes of heterogeneous photocatalysts, mechanisms and reactive intermediates of photocatalytic reactions of sulfur aromatic compounds, and the selectivity of these reactions. Quantum chemical calculations of properties and structures of sulfur aromatic compounds, their reactive intermediates, and the structure of adsorption complexes formed on the surface of the photocatalysts are also discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Thermal comfort

    DEFF Research Database (Denmark)

    d’Ambrosio Alfano, Francesca Romana; Olesen, Bjarne W.; Palella, Boris Igor

    2014-01-01

    Thermal comfort is one of the most important aspects of the indoor environmental quality due to its effects on well-being, people's performance and building energy requirements. Its attainment is not an easy task requiring advanced design and operation of building and HVAC systems, taking...... under specific conditions. At operation level, only few variables are taken into account with unpredictable effects on the assessment of comfort indices. In this paper, the main criteria for the design and assessment of thermal comfort are discussed in order to help building and HVAC systems designers...... into account all parameters involved. Even though thermal comfort fundamentals are consolidated topics for more than forty years, often designers seem to ignore or apply them in a wrong way. Design input values from standards are often considered as universal values rather than recommended values to be used...

  13. Thermal defoliation

    Science.gov (United States)

    The negative perception some consumers hold regarding agricultural chemicals has resulted in an increased demand for organic foods and fibers, and in increasing political pressure for the regulation of agricultural production practices. This has revived interest in thermal defoliation of cotton and ...

  14. Holographic thermalization

    NARCIS (Netherlands)

    Balasubramanian, V.; Bernamonti, A.; de Boer, J.; Copland, N.; Craps, B.; Keski-Vakkuri, E.; Müller, B.; Schäfer, A.; Shigemori, M.; Staessens, W.

    2011-01-01

    Using the AdS/CFT correspondence, we probe the scale-dependence of thermalization in strongly coupled field theories following a quench, via calculations of two-point functions, Wilson loops and entanglement entropy in d=2,3,4. In the saddlepoint approximation these probes are computed in AdS space

  15. Thermal Hardware for the Thermal Analyst

    Science.gov (United States)

    Steinfeld, David

    2015-01-01

    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Space Flight Center (GSFC) Thermal Engineering Branch (Code 545). NCTS 21070-1. Most Thermal analysts do not have a good background into the hardware which thermally controls the spacecraft they design. SINDA and Thermal Desktop models are nice, but knowing how this applies to the actual thermal hardware (heaters, thermostats, thermistors, MLI blanketing, optical coatings, etc...) is just as important. The course will delve into the thermal hardware and their application techniques on actual spacecraft. Knowledge of how thermal hardware is used and applied will make a thermal analyst a better engineer.

  16. Next Generation Nuclear Plant Materials Research and Development Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    G. O. Hayner; E.L. Shaber

    2004-09-01

    The U.S Department of Energy (DOE) has selected the Very High Temperature Reactor (VHTR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production without greenhouse gas emissions. The reactor design will be a graphite moderated, helium-cooled, prismatic or pebble-bed, thermal neutron spectrum reactor that will produce electricity and hydrogen in a state-of-the-art thermodynamically efficient manner. The NGNP will use very high burn-up, low-enriched uranium, TRISO-coated fuel and have a projected plant design service life of 60 years.

  17. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

    Science.gov (United States)

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-01-01

    Abstract Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography–mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

  18. Thiophenic Sulfur Compounds Released During Coal Pyrolysis.

    Science.gov (United States)

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-06-01

    Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography-mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ . Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis.

  19. Thermal conductivity of rare earth-uranium ternary oxides of the type RE 6UO 12

    Science.gov (United States)

    Krishnaiah, M. V.; Seenivasan, G.; Srirama Murti, P.; Mathews, C. K.

    2002-11-01

    The knowledge of thermophysical properties of the rare earth uranium ternary oxides of the type RE 6UO 12 (RE=La, Gd and Dy) is essential to understand the fuel performance during reactor operation and for modeling fuel behavior. Literature on the high temperature properties of this compound is not available and there is no report at all on the thermal conductivity of these compounds. Hence a study of thermal conductivity of this compound has been taken up. The compounds were synthesized by a solution combustion method using metal nitrates and urea. Thermal diffusivity of these compounds was measured by the laser flash method in the temperature range 673-1373 K. The specific heat data was computed using Neumann-Kopp's law. Thermal conductivity was calculated using the measured thermal diffusivity value, density and specific heat data for different temperatures. The temperature dependence of thermal conductivity and the implication of structural aspects of these compounds on the data are discussed here.

  20. Thermal Clothing

    Science.gov (United States)

    1997-01-01

    Gateway Technologies, Inc. is marketing and developing textile insulation technology originally developed by Triangle Research and Development Corporation. The enhanced thermal insulation stems from Small Business Innovation Research contracts from NASA's Johnson Space Center and the U.S. Air Force. The effectiveness of the insulation comes from the microencapsulated phase-change materials originally made to keep astronauts gloved hands warm. The applications for the product range from outer wear, housing insulation, and blankets to protective firefighting gear and scuba diving suits. Gateway has developed and begun marketing thermal regulating products under the trademark, OUTLAST. Products made from OUTLAST are already on the market, including boot and shoe liners, winter headgear, hats and caps for hunting and other outdoor sports, and a variety of men's and women's ski gloves.

  1. Turbulent Thermalization

    CERN Document Server

    Micha, Raphael; Micha, Raphael; Tkachev, Igor I.

    2004-01-01

    We study, analytically and with lattice simulations, the decay of coherent field oscillations and the subsequent thermalization of the resulting stochastic classical wave-field. The problem of reheating of the Universe after inflation constitutes our prime motivation and application of the results. We identify three different stages of these processes. During the initial stage of ``parametric resonance'', only a small fraction of the initial inflaton energy is transferred to fluctuations in the physically relevant case of sufficiently large couplings. A major fraction is transfered in the prompt regime of driven turbulence. The subsequent long stage of thermalization classifies as free turbulence. During the turbulent stages, the evolution of particle distribution functions is self-similar. We show that wave kinetic theory successfully describes the late stages of our lattice calculation. Our analytical results are general and give estimates of reheating time and temperature in terms of coupling constants and...

  2. Experimental study and kinetic modeling of the thermal degradation of aromatic volatile organic compounds (benzene, toluene and xylene-para) in methane flames; Etude experimentale et modelisation cinetique de la degradation thermique des composes organiques volatils aromatiques benzenes, toluene et para-xylene dans des flammes de methane

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, L.

    2001-02-01

    This study treats of the thermal degradation of a family of aromatic volatile organic compounds (VOCs) in laminar premixed methane flames at low pressure. The experimental influence of benzene, toluene and xylene-para on the structure of a reference methane flame has been studied. The molar fraction profiles of the stable and reactive, aliphatic, aromatic and cyclic species have been established by the coupling of the molecular beam sampling/mass spectroscopy technique with the gas chromatography/mass spectroscopy technique. Temperature profiles have been measured using a covered thermocouple. A detailed kinetic mechanism of oxidation of these compounds in flame conditions has been developed. Different available sub-mechanisms have been used as references: the GDF-Kin 1.0 model for the oxidation of methane and the models of Tan and Franck (1996) and of Lindstedt and Maurice (1996) in the case of benzene and toluene. In the case of para-xylene, a model has been developed because no mechanisms was available in the literature. These different mechanisms have been refined, completed or adjusted by comparing the experimental results with those obtained by kinetic modeling. The complete kinetic mechanism, comprising 156 chemical species involved in 1072 reactions allows to reproduce all the experimental observations in a satisfactory manner. The kinetic analysis of reactions velocity has permitted to determine oxidation kinetic schemes for benzene, toluene, xylene-para and for the cyclopentadienyl radical, main species at the origin of the rupture of the aromatic cycle. Reactions of recombination with the methyl radicals formed during methane oxidation, of the different aromatic or aliphatic radicals created during the oxidation of aromatics, play an important role and lead to the formation of several aromatic pollutants (ethyl-benzene for instance) or aliphatic pollutants (butadiene or penta-diene for instance) in flames. (J.S.)

  3. NOUN COMPOUND IN ENGLISH

    Directory of Open Access Journals (Sweden)

    Ni Luh Ketut Mas Indrawati

    2013-11-01

    Full Text Available This paper aims at analyzing and describing the English compound specifically the English noun compound. Compound is a combination of two or more words of which meaning cannot always be predicted from the meaning of each part. In English, words, especially adjectives and nouns, are combined into compound structures in a variety of ways. This article attempts to discuss the formal characteristics and types of the English noun compound. The theory of compound was adopted for further analysis. The finding shows that the formal characteristics of the English noun compound are: the noun compounds have primary stress on the first constituent, the semantic unity of a noun compound is reflected in an orthographic, the meaning of the noun compound cannot be predicted from the meaning of the parts. The orthographic characteristics can be solid, hyphenated, and open. The types involved are Subject and Verb, Verb and Object, verb and adverbial, verb-less, subject and complement, combining-form and Bahuvrihi

  4. Diamond as a solid state micro-fission chamber for thermal neutron detection at the VR-1 research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pomorski, Michal; Mer-Calfati, Christine [CEA-LIST, Diamond Sensors Laboratory, 91191, Gif-sur-Yvette (France); Foulon, Francois [CEA, National Institute for Nuclear Science and Technology, 91191, Gif-sur-Yvette (France); Sklenka, Lubomir; Rataj, Jan; Bily, Tomas [Department of Nuclear Reactors,Faculty of Nuclear Science and Physical Engineering, Czech Technical University, V. Holesovickach 2, 180 00 PRAHA 8 (Czech Republic)

    2015-07-01

    Prague. The Training Reactor VR-1 is a pool type (light water) reactor based on UO{sub 2} low enriched uranium. It has a nominal power of 1 kW, and can be operated for a short period up to 5 kW. The arrangement of the reactor pool reactor facilitates access to the core, setting and removal of various experimental samples and detectors, and safe and easy handling of fuel assemblies. The reactor is equipped with two horizontal channels (radial and tangential) and 10 vertical channels, of varying diameters, which can be loaded into various core positions, and one pneumatic transfer system. It is also equipped with several specifically designed educational instrumentation systems that can be used to supply complementary measurements and characterization around the reactor. The reactor is operated by the Department of Nuclear Reactors of the Faculty of Nuclear Sciences and Physical Engineering of the Czech Technical University in Prague. The two detectors were placed in-core through one of the vertical insertion channel. They were coupled to remote placed (5 m BNC cable) classical nuclear charge sensitive electronics. Detection properties of both sensors, including: pulse height spectra of U-235 fission fragments (response linearity with neutron flux, count rate, gamma background, were evaluated varying the power of the reactor from 0.005 W to 500 W. The evolution of the counting rate of the thinned optical grade detector as a function of counting rate of a gas ionization chamber used currently for reactor monitoring shows the very good linearity of the detector over the 5 decades. Similar results were obtained with the PIM detector. Additionally fast transient current signals of the detectors were recorded on a digital storage oscilloscope (DSO) using broad-band amplifier and with a simple bias-T, showing potential use of such sensors for neutron counting with no need of an amplification stage, since non-amplified signals from fission fragments exceeded 4 mV in amplitude

  5. Caracterização mecânica e térmica da borracha natural formulada e vulcanizada dos clones: GT 1, IAN 873, PB 235 e RRIM 600 Mechanical and thermal characterization of compounds of natural rubber of the clones: GT 1, IAN 873, PB 235 and RRIM 600

    Directory of Open Access Journals (Sweden)

    Ana C. Dall'Antonia

    2009-01-01

    Full Text Available Neste trabalho estudou-se o desempenho mecânico e térmico de compostos de borracha natural (Hevea brasiliensis de 4 diferentes clones (GT 1, IAN 873, PB 235 e RRIM 600 cultivados no Estado de São Paulo, assim como de uma mistura destes clones e de uma borracha comercial, GEB-1. Estas borrachas foram formuladas e vulcanizadas com tempos de 5, 7 e 9 minutos. A caracterização foi realizada por calorimetria exploratória diferencial, termogravimetria, ensaios de resistência à tração, análise dinâmico-mecânica, medidas de dureza Shore A, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. Os resultados permitiram concluir que o tempo de vulcanização e o tipo de clone não influenciaram na temperatura de transição vítrea (Tg dos compostos. Os valores de Tg obtidos por DMA foram de cerca de -62 °C, e os resultados ensaios de dureza apresentaram valores próximos de 60 para todos os compostos estudados. Os ensaios de resistência à tração mostraram que o melhor desempenho mecânico foi obtido pelo clone RRIM 600. De acordo com os resultados obtidos neste trabalho, todos os clones atingiram as propriedades reportadas na literatura, podendo ser utilizados, em princípio, nas indústrias de artefatos de borracha separadamente ou na forma de mistura.The objective of this work was to study the mechanical and thermal performance of natural rubber (Hevea brasiliensis compounds of different types of clones (GT 1, IAN 873, PB 235 and RRIM 600, as well as a mixture made from these clones and a commercial rubber GEB-1. These rubbers were formulated and prepared in a two-roll mill and vulcanized at different times (5, 7 and 9 minutes. The evaluation of the mechanical and thermal performance of different natural rubber compounds was carried out by differential scanning calorimetry (DSC, thermogravimetry analysis (TGA, mechanical properties (tensile and hardness tests, dynamic mechanic thermal analysis (DMTA

  6. Thermal insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.

    1985-07-16

    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  7. Ultrasound assisted extraction of bioactive compounds

    Directory of Open Access Journals (Sweden)

    Helena Drmić

    2010-01-01

    Full Text Available Many novel and innovative techniques are nowadays researched and explored in order to replace or improve classical, thermal processing technologies. One of newer technique is technique of minimal food processing, under what we assume ultrasound processing. Ultrasound technology can be very useful for minimal food processing because transmission of acoustic energy through product is fast and complete, which allows reduction in total processing time, and therefore lower energy consumption. Industrial processing is growing more and more waste products, and in desire of preservation of global recourses and energy efficiency, several ways of active compounds extraction techniques are now explored. The goal is to implement novel extraction techniques in food and pharmaceutical industry as well in medicine. Ultrasound assisted extraction of bioactive compounds offers increase in yield, and reduction or total avoiding of solvent usage. Increase in temperature of treatment is controlled and restricted, thereby preserving extracted bioactive compounds. In this paper, several methods of ultrasound assisted extraction of bioactive compounds from plant materials are shown. Ultrasound can improve classic mechanisms of extraction, and thereby offer novel possibilities of commercial extraction of desired compounds. Application of sonochemistry (ultrasound chemistry is providing better yield in desired compounds and reduction in treatment time.

  8. Coordination Compounds in Biology

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 6. Coordination Compounds in Biology - The Chemistry of Vitamin B12 and Model Compounds. K Hussian Reddy. General Article Volume 4 Issue 6 June 1999 pp 67-77 ...

  9. Optical and thermal performance of a three-dimensional compound ...

    Indian Academy of Sciences (India)

    The time constant of the 3D CPC (431 s) was fairly high when compared with the 2D CPC (110 s). An attempt was made to generate low pressure steam using 3D CPC in the in situ steam generation mode. The efficiency of the steam generation was about 38%, which was one of the possible applications of 3D CPC module.

  10. Optical and thermal performance of a three-dimensional compound ...

    Indian Academy of Sciences (India)

    and revive interest on renewable, solar energy utilization options. Flat plate collectors have been widely used for applications that demand below 90. ◦. C and large amount of research efforts are already made. For medium temperature range (90–300. ◦. C) applications, concentrating type collectors are suitable, which are ...

  11. Thermal decomposition of potassium bis-oxalatodiaqua-indate (III ...

    Indian Academy of Sciences (India)

    2] 3H2O. Thermal decomposition studies show that the compound decomposes first to the anhydrous potassium indium oxalate ... Bio-inorganic Chemistry Laboratories, School of Chemistry, Andhra University, Visakhapatnam 530 003, India ...

  12. Advanced thermally stable jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  13. Antimicrobial azobenzene compounds and their potential use in biomaterials

    Science.gov (United States)

    Sessa, L.; Concilio, S.; Iannelli, P.; De Santis, F.; Porta, A.; Piotto, S.

    2016-04-01

    We recently synthesized a class of active compounds with azobenzene structure [1] and lowest in silico toxicity values. The antimicrobial activity of these molecules and their thermal stability are very promising and indicate that they may have interesting and therapeutically significant applications. This work aims to develop new materials with antibacterial and antifungal activity inserting different percentages of synthetic antimicrobial azo compounds in commercial polymer matrices. We realized thin films using solvent casting and melt compounding techniques. The obtained materials retained the proprieties of the pure matrices. This means that azo dye dissolved in the matrix does not influence the thermal behavior and the morphology of the material. Tested films exhibited the capability to inhibit biofilms formation of S. aureus and C. albicans. Spectrophotometric investigation of the azo compound released from the polymer matrices confirmed that the realized materials might be interesting for biomedical tools, antibacterial surfaces, and films for active packaging.

  14. MEA 86 Compound data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data file contains the full raw parameter data for the 86 compounds tested in the developmental MEA assay, as well as Area Under the Curve (AUC) calculations...

  15. Chemistry of peroxide compounds

    Science.gov (United States)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  16. Phenolic compounds in flaxseed

    OpenAIRE

    Johnsson, Pernilla

    2004-01-01

    The dietary lignan secoisolariciresinol diglucoside (SDG), present in high concentrations in flaxseed, and its metabolites enterolactone and enterodiol are thought to decrease the risk of hormone dependent cancers, cardiovascular disease and other “welfare” diseases. Flaxseed also contains other biologically active phenolic compounds, such as phenolic acids. The understanding of the nature of these compounds is crucial for their possible exploitation in drugs and functional foods. Until the m...

  17. Biodegradation of Organofluorine Compounds

    Science.gov (United States)

    2016-02-01

    3.1 Enrichment Cultures One approach to the identification of degradative enzymes is to “feed” the compound of interest (COI) to a...Defluorination of Organofluorine Sulfur Compounds by Pseudomonas Sp. Strain D2. Environ. Sci. Technol. 1998, 32, 2283–2287. 2. Chan, P.W.Y.; Yakunin...document format ( pdf ) electronic version of this report: U.S. Army Edgewood Chemical Biological Center RDCB-DRB-C ATTN: Dixon, M

  18. Nomenclature of chemical compounds

    OpenAIRE

    Karolina Kaczmarek

    2009-01-01

    This article presents the mechanisms of the inorganic chemistry nomenclature formation in French language. It shows the structure and the way of presenting the names of chemical compounds either descriptively or by giving the structural formulas’ characteristics, their transcription and order of reading the letters. The text specifies the rules of naming a chemical compound, according to the criteria of IUPAC (Union of Pure and Applied Chemistry), the organisation responsible for digesting th...

  19. Chromium (V) compounds as cathode material in electrochemical power sources

    Science.gov (United States)

    Delnick, F.M.; Guidotti, R.A.; McCarthy, D.K.

    A cathode for use in a thermal battery, comprising a chromium (V) compound. The preferred materials for this use are Ca/sub 5/(CrO/sub 4/)/sub 3/Cl, Ca/sub 5/(CrO/sub 4/)OH, and Cr/sub 2/O/sub 5/. The chromium (V) compound can be employed as a cathode material in ambient temperature batteries when blended with a suitably conductive filler, preferably carbon black.

  20. Thermal degradation kinetics and solid state, temperature ...

    Indian Academy of Sciences (India)

    WINTEC

    Phenothiazine derivatives belong to a big group of aromatic compounds. These derivatives are substituted in ... Elemental analysis for carbon, hydrogen, nitrogen and sulphur were done using Vario EL III CHNS ... The aim of the kinetic study of thermal analysis data is to find out the most probable kinetic model which best ...

  1. Phenolic Molding Compounds

    Science.gov (United States)

    Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

    Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

  2. Spin state switching in iron coordination compounds

    Directory of Open Access Journals (Sweden)

    Philipp Gütlich

    2013-02-01

    Full Text Available The article deals with coordination compounds of iron(II that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices.The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II, with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligo- and polynuclear iron(II complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property.

  3. Seasonal thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

    1984-05-01

    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  4. Fundamentals of Thermal Expansion and Thermal Contraction

    OpenAIRE

    Liu, Zi-Kui; Shang, Shun-Li; Wang, Yi

    2017-01-01

    Thermal expansion is an important property of substances. Its theoretical prediction has been challenging, particularly in cases the volume decreases with temperature, i.e., thermal contraction or negative thermal expansion at high temperatures. In this paper, a new theory recently developed by the authors has been reviewed and further examined in the framework of fundamental thermodynamics and statistical mechanics. Its applications to cerium with colossal thermal expansion and Fe3Pt with th...

  5. Nomenclature of chemical compounds

    Directory of Open Access Journals (Sweden)

    Karolina Kaczmarek

    2009-01-01

    Full Text Available This article presents the mechanisms of the inorganic chemistry nomenclature formation in French language. It shows the structure and the way of presenting the names of chemical compounds either descriptively or by giving the structural formulas’ characteristics, their transcription and order of reading the letters. The text specifies the rules of naming a chemical compound, according to the criteria of IUPAC (Union of Pure and Applied Chemistry, the organisation responsible for digesting the chemical nomenclature. The article contains the transcription chart and the manner of reading the structural formula, also called latero-numerical. Additionally, there is information conceming the usage of the common names given, still remaining in use next to the names compatible with those of IUPAC. Particular types of chemical compounds have served as models for description of other nomenclature formation rules from the simplest structures to the complicated compound ones. A short summary presents the relations and similarities between the names of particular types of chemical compounds.

  6. Rocket Motor Joint Construction Including Thermal Barrier

    Science.gov (United States)

    Steinetz, Bruce M. (Inventor); Dunlap, Patrick H., Jr. (Inventor)

    2002-01-01

    A thermal barrier for extremely high temperature applications consists of a carbon fiber core and one or more layers of braided carbon fibers surrounding the core. The thermal barrier is preferably a large diameter ring, having a relatively small cross-section. The thermal barrier is particularly suited for use as part of a joint structure in solid rocket motor casings to protect low temperature elements such as the primary and secondary elastomeric O-ring seals therein from high temperature gases of the rocket motor. The thermal barrier exhibits adequate porosity to allow pressure to reach the radially outward disposed O-ring seals allowing them to seat and perform the primary sealing function. The thermal barrier is disposed in a cavity or groove in the casing joint, between the hot propulsion gases interior of the rocket motor and primary and secondary O-ring seals. The characteristics of the thermal barrier may be enhanced in different applications by the inclusion of certain compounds in the casing joint, by the inclusion of RTV sealant or similar materials at the site of the thermal barrier, and/or by the incorporation of a metal core or plurality of metal braids within the carbon braid in the thermal barrier structure.

  7. Efeito do tratamento térmico na concentração de carotenóides, compostos fenólicos, ácido ascórbico e capacidade antioxidante do suco de tangerina murcote Effect of thermal treatment on the carotenoid, phenolic compound and ascorbic acid concentrations, and the antioxidant capacity of murcott tangerine juice

    Directory of Open Access Journals (Sweden)

    André de Souza Dutra

    2012-09-01

    possibilitaram menores alterações e/ou maiores retenções nos compostos determinados.This study evaluated the effect of thermal treatment on the total carotenoid concentration, the carotenoid profile (lutein, zeaxanthin, β-cryptoxanthin and β-carotene, total phenolic compound content, ascorbic acid content and antioxidant capacity of Murcott Tangerine juice. Using a tubular heat exchanger eleven treatments were evaluated based on a full 2² factorial design with three replicates at the central point, four axial points and a region of observation from 88 to 100 ºC and from 16 to 44 s. The total carotenoid content decreased significantly in almost all treatments when compared with the results obtained for the fresh juice. The carotenoid levels (lutein, zeaxanthin and β-cryptoxanthin were not significantly reduced by most of the treatments studied, and the β-carotene content was not significantly changed by any treatment. For the carotenoid contents, the analysis of variance showed no significant interactions between the variables of temperature and time. The levels of ascorbic acid and total phenolic compounds decreased in six of the conditions evaluated, while in four treatments an increase in the total phenolic compounds was observed, probably due to evaporation of water from the juice. The greatest reduction and the greatest increase of, respectively, ascorbic acid and total phenolic compounds were observed for the binomial of 100 ºC/30 s. The ascorbic acid content was significantly influenced by the temperature, and its degradation process can be described using a quadratic model. All the treatments applied reduced the antioxidant capacity of the juice, but the reduction was higher for the binomial 100 ºC/30 s. The nutritional characteristics of the juice were little affected by the changes observed, and the heat treatments carried out at 94 ºC for 16 to 44 s allowed for the smallest changes and/or the highest retentions of the determined compounds.

  8. Compound Droplets on Fibers.

    Science.gov (United States)

    Weyer, Floriane; Ben Said, Marouen; Hötzer, Johannes; Berghoff, Marco; Dreesen, Laurent; Nestler, Britta; Vandewalle, Nicolas

    2015-07-21

    Droplets on fibers have been extensively studied in the recent years. Although the equilibrium shapes of simple droplets on fibers are well established, the situation becomes more complex for compound fluidic systems. Through experimental and numerical investigations, we show herein that compound droplets can be formed on fibers and that they adopt specific geometries. We focus on the various contact lines formed at the meeting of the different phases and we study their equilibrium state. It appears that, depending on the surface tensions, the triple contact lines can remain separate or merge together and form quadruple lines. The nature of the contact lines influences the behavior of the compound droplets on fibers. Indeed, both experimental and numerical results show that, during the detachment process, depending on whether the contact lines are triple or quadruple, the characteristic length is the inner droplet radius or the fiber radius.

  9. Compound semiconductor device physics

    CERN Document Server

    Tiwari, Sandip

    2013-01-01

    This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter

  10. Synthetic Aperture Compound Imaging

    DEFF Research Database (Denmark)

    Hansen, Jens Munk

    Medical ultrasound imaging is used for many purposes, e.g. for localizing and classifying cysts, lesions, and other processes. Almost any mass is first observed using B-mode imaging and later classified using e.g. color flow, strain, or attenuation imaging. It is therefore important that the B...... region of parenchyma. A successful approach to reduce the speckle artifacts is spatial compounding, where images are acquired from a number of directions and combined after envelope-detection. Today, spatial compounding is implemented in all highend ultrasound systems and available when using a low pitch...

  11. Prediction of intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Burkhanov, Gennady S; Kiselyova, N N [A A Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Moscow (Russian Federation)

    2009-06-30

    The problems of predicting not yet synthesized intermetallic compounds are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is faced with the complexity of presenting multidimensional phase diagrams. One way of predicting new intermetallics with specified properties is the use of modern processing technology with application of teaching of image recognition by the computer. The algorithms used most often in these methods are briefly considered and the efficiency of their use for predicting new compounds is demonstrated.

  12. Thermal Ignition

    Science.gov (United States)

    Boettcher, Philipp Andreas

    Accidental ignition of flammable gases is a critical safety concern in many industrial applications. Particularly in the aviation industry, the main areas of concern on an aircraft are the fuel tank and adjoining regions, where spilled fuel has a high likelihood of creating a flammable mixture. To this end, a fundamental understanding of the ignition phenomenon is necessary in order to develop more accurate test methods and standards as a means of designing safer air vehicles. The focus of this work is thermal ignition, particularly auto-ignition with emphasis on the effect of heating rate, hot surface ignition and flame propagation, and puffing flames. Combustion of hydrocarbon fuels is traditionally separated into slow reaction, cool flame, and ignition regimes based on pressure and temperature. Standard tests, such as the ASTM E659, are used to determine the lowest temperature required to ignite a specific fuel mixed with air at atmospheric pressure. It is expected that the initial pressure and the rate at which the mixture is heated also influences the limiting temperature and the type of combustion. This study investigates the effect of heating rate, between 4 and 15 K/min, and initial pressure, in the range of 25 to 100 kPa, on ignition of n-hexane air mixtures. Mixtures with equivalence ratio ranging from 0.6 to 1.2 were investigated. The problem is also modeled computationally using an extension of Semenov's classical auto-ignition theory with a detailed chemical mechanism. Experiments and simulations both show that in the same reactor either a slow reaction or an ignition event can take place depending on the heating rate. Analysis of the detailed chemistry demonstrates that a mixture which approaches the ignition region slowly undergoes a significant modification of its composition. This change in composition induces a progressive shift of the explosion limit until the mixture is no longer flammable. A mixture that approaches the ignition region

  13. Intercalation compounds involving inorganic layered structures

    Directory of Open Access Journals (Sweden)

    CONSTANTINO VERA R. L.

    2000-01-01

    Full Text Available Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts.

  14. Synthesis and characterization of phenylethynylcarbonyl terminated novel thermosetting imide compound

    Directory of Open Access Journals (Sweden)

    H. Kimura

    2013-02-01

    Full Text Available Phenylethynyl terminated novel imide compound based on 1,3-bis(3-aminophenoxybenzene (APB and phenylethynyl trimellitic anhydride (PETA were prepared. The curing behavior of phenylethynyl terminated imide compound was investigated by differential scanning calorimetry and Fourier transform infrared spectrometry. The curing reaction of phenylethynylcarbonyl end group completed at 220°C, and proceeded much faster than that of phenylethynyl end group. Glass transition temperature of the thermosetting resin from phenylethynylcarbonyl terminated novel imide compound determined by dynamic mechanical analysis was almost the same as that of o-cresolnovolac type epoxy resin. In addition, the thermosetting resin from phenylethynylcarbonyl terminated novel imide compound exhibited excellent thermal and dimensional stabilities. These excellent properties of these phenylethynyl terminated imide compound might be due to the incorporation of alkene group or aromatic ring substitutes in the backbones, which might enhance the chain interaction (molecular packing and reduce the molecular chain mobility.

  15. Complex compound polyvinyl alcohol-titanic acid/titanium dioxide

    Science.gov (United States)

    Prosanov, I. Yu.

    2013-02-01

    A complex compound polyvinyl alcohol-titanic acid has been produced and investigated by means of IR and Raman spectroscopy, X-ray diffraction, and synchronous thermal analysis. It is claimed that it represents an interpolymeric complex of polyvinyl alcohol and hydrated titanium oxide.

  16. A Study of Solar Thermal Propulsion System Enhancement via Thermal Storage and Thermal-electric Conversion

    Science.gov (United States)

    2010-03-24

    material. Molybdenum has a thermal conductivity of 138 W/mK, while rheniums is much lower at 39.6 W/mK 2 . Zirconium Boride (ZrB2) and Hafnium Boride ...14,000 Iridium 77 2739 213 147 $42,000 Niobium 41 2750 323 53.7 $170 Molybdenum 42 2896 390 138 $100 The materials listed in Table 1 do not...this paper, several materials with melting points above 3000 K are boride compounds and several of those that are not borides contain elements which

  17. Polymeric coordination compounds

    Indian Academy of Sciences (India)

    Administrator

    Metal coordination polymers with one- and two-dimensional structures are of current interest due to their possible relevance to material science 1. In continuation of our previous studies 2,3, several new polymeric compounds are reported here. Among the complexes of silver with aminomethyl pyridine (amp) ...

  18. NATURAL POLYACETYLENE COMPOUNDS

    Directory of Open Access Journals (Sweden)

    A. M. Nasukhova

    2014-01-01

    Full Text Available In article the review of the initial stage of researches of natural polyacetylene compounds is resulted. The high reactionary ability leading to fast oxidation and degradation of these compounds, especially at influence of Uf-light, oxygen of air, pH and other factors, has caused the serious difficulties connected with an establishment of structure and studying of their physical and chemical properties. Therefore the greatest quantity of works of this stage is connected with studying of essential oils of plants from families Apiaceae, Araliaceae, Asteraceae, Campanulaceae, Olacaceae, Pittosporaceae and Santalaceae where have been found out, basically, diacetylene compounds. About development of physical and chemical methods of the analysis of possibility of similar researches have considerably extended. More than 2000 polyacetylenes are known today, from them more than 1100 are found out in plants fam. Asteraceae. Revolution in the field of molecular biology has allowed to study processes of biosynthesis of these compounds intensively.

  19. Toxicology of perfluorinated compounds

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Thorsten [Hessian State Laboratory, Wiesbaden (Germany); Mattern, Daniela; Brunn, Hubertus [Hessian State Laboratory, Giessen (Germany)

    2011-12-15

    Perfluorinated compounds [PFCs] have found a wide use in industrial products and processes and in a vast array of consumer products. PFCs are molecules made up of carbon chains to which fluorine atoms are bound. Due to the strength of the carbon/fluorine bond, the molecules are chemically very stable and are highly resistant to biological degradation; therefore, they belong to a class of compounds that tend to persist in the environment. These compounds can bioaccumulate and also undergo biomagnification. Within the class of PFC chemicals, perfluorooctanoic acid and perfluorosulphonic acid are generally considered reference substances. Meanwhile, PFCs can be detected almost ubiquitously, e.g., in water, plants, different kinds of foodstuffs, in animals such as fish, birds, in mammals, as well as in human breast milk and blood. PFCs are proposed as a new class of 'persistent organic pollutants'. Numerous publications allude to the negative effects of PFCs on human health. The following review describes both external and internal exposures to PFCs, the toxicokinetics (uptake, distribution, metabolism, excretion), and the toxicodynamics (acute toxicity, subacute and subchronic toxicities, chronic toxicity including carcinogenesis, genotoxicity and epigenetic effects, reproductive and developmental toxicities, neurotoxicity, effects on the endocrine system, immunotoxicity and potential modes of action, combinational effects, and epidemiological studies on perfluorinated compounds). (orig.)

  20. Computing compound distributions faster

    OpenAIRE

    Iseger, P.; Smith, M.A.J.; Dekker, Rommert

    1997-01-01

    textabstractThe use of Panjer's algorithm has meanwhile become a widespread standard technique for actuaries (Kuon et al., 1955). Panjer's recursion formula is used for the evaluation of compound distributions and can be applied to life and general insurance problems. The discrete version of Panjer's recursion formula is often applied to continuous distributions by discretizing the

  1. Computing compound distributions faster

    NARCIS (Netherlands)

    P. den Iseger; M.A.J. Smith; R. Dekker (Rommert)

    1997-01-01

    textabstractThe use of Panjer's algorithm has meanwhile become a widespread standard technique for actuaries (Kuon et al., 1955). Panjer's recursion formula is used for the evaluation of compound distributions and can be applied to life and general insurance problems. The discrete version of

  2. Coordination Compounds in Biology

    Indian Academy of Sciences (India)

    inorganic chemistry has been uncovered while studying sys- tems pertinent to B. 12 ... inorganic chemistry. His research interests are in the chemistry of model compounds of biochemical relevance. He did post- doctoral research in the. University of ..... G N Schrauzer, in Advances in Chemistry series, No. 100, Ed. R F.

  3. Xenobiotic organic compounds in wastewater

    DEFF Research Database (Denmark)

    Eriksson, Eva; Baun, Anders; Henze, Mogens

    2002-01-01

    Information regarding the contents of xenobiotic organic compounds (XOCs) in wastewater is limited, but it has been shown that at least 900 different compounds / compound groups could potentially be present in grey wastewater. Analyses of Danish grey wastewater revealed the presence of several hu...... aquatic toxicity were present and that data for environmental fate could only be retrieved for about half of the compounds....

  4. High performance UV and thermal cure hybrid epoxy adhesive

    Science.gov (United States)

    Chen, C. F.; Iwasaki, S.; Kanari, M.; Li, B.; Wang, C.; Lu, D. Q.

    2017-06-01

    New type one component UV and thermal curable hybrid epoxy adhesive was successfully developed. The hybrid epoxy adhesive is complete initiator free composition. Neither photo-initiator nor thermal initiator is contained. The hybrid adhesive is mainly composed of special designed liquid bismaleimide, partially acrylated epoxy resin, acrylic monomer, epoxy resin and latent curing agent. Its UV light and thermal cure behavior was studied by FT-IR spectroscopy and FT-Raman spectroscopy. Adhesive samples cured at UV only, thermal only and UV + thermal cure conditions were investigated. By calculated conversion rate of double bond in both acrylic component and maleimide compound, satisfactory light curability of the hybrid epoxy adhesive was confirmed quantitatively. The investigation results also showed that its UV cure components, acrylic and bismalimide, possess good thermal curability too. The initiator free hybrid epoxy adhesive showed satisfactory UV curability, good thermal curability and high adhesion performance.

  5. Steady-State Thermal-Hydraulics Analyses for the Conversion of the BR2 Reactor to LEU

    Energy Technology Data Exchange (ETDEWEB)

    Licht, J. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Bergeron, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Dionne, B. [Argonne National Lab. (ANL), Argonne, IL (United States); Van den Branden, G. [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium); Kalcheva, S [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium); Sikik, E [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium); Koonen, E [Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium)

    2016-09-01

    BR2 is a research reactor used for radioisotope production and materials testing. It’s a tank-in-pool type reactor cooled by light water and moderated by beryllium and light water. The reactor core consists of a beryllium moderator forming a matrix of 79 hexagonal prisms in a hyperboloid configuration; each having a central bore that can contain a variety of different components such as a fuel assembly, a control or regulating rod, an experimental device, or a beryllium or aluminum plug. Based on a series of tests, the BR2 operation is currently limited to a maximum allowable heat flux of 470 W/cm2 to ensure fuel plate integrity during steady-state operation and after a loss-of-flow/loss-of-pressure accident. A feasibility study for the conversion of the BR2 reactor from highly-enriched uranium (HEU) to low-enriched uranium (LEU) fuel was previously performed to verify it can operate safely at the same maximum nominal steady-state heat flux. An assessment was also performed to quantify the heat fluxes at which the onset of flow instability and critical heat flux occur for each fuel type. This document updates and expands these results for the current representative core configuration (assuming a fresh beryllium matrix) by evaluating the onset of nucleate boiling (ONB), onset of fully developed nucleate boiling (FDNB), onset of flow instability (OFI) and critical heat flux (CHF).

  6. Dynamic thermal environment and thermal comfort.

    Science.gov (United States)

    Zhu, Y; Ouyang, Q; Cao, B; Zhou, X; Yu, J

    2016-02-01

    Research has shown that a stable thermal environment with tight temperature control cannot bring occupants more thermal comfort. Instead, such an environment will incur higher energy costs and produce greater CO2 emissions. Furthermore, this may lead to the degeneration of occupants' inherent ability to combat thermal stress, thereby weakening thermal adaptability. Measured data from many field investigations have shown that the human body has a higher acceptance to the thermal environment in free-running buildings than to that in air-conditioned buildings with similar average parameters. In naturally ventilated environments, occupants have reported superior thermal comfort votes and much greater thermal comfort temperature ranges compared to air-conditioned environments. This phenomenon is an integral part of the adaptive thermal comfort model. In addition, climate chamber experiments have proven that people prefer natural wind to mechanical wind in warm conditions; in other words, dynamic airflow can provide a superior cooling effect. However, these findings also indicate that significant questions related to thermal comfort remain unanswered. For example, what is the cause of these phenomena? How we can build a comfortable and healthy indoor environment for human beings? This article summarizes a series of research achievements in recent decades, tries to address some of these unanswered questions, and attempts to summarize certain problems for future research. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Iterative elimination algorithm for thermal image processing

    Directory of Open Access Journals (Sweden)

    A. H. Alkali

    2014-08-01

    Full Text Available Segmentation is employed in everyday image processing, in order to remove unwanted objects present in the image. There are scenarios where segmentation alone does not do the intended job automatically. In such cases, subjective means are required to eliminate the remnants which are time consuming especially when multiple images are involved. It is also not feasible when real-time applications are involved. This is even compounded when thermal imaging is involved as both foreground and background objects can have similar thermal distribution, thus making it impossible for straight segmentation to distinguish between the two. In this study, a real-time Iterative Elimination Algorithm (IEA was developed and it was shown that false foreground was removed in thermal images where segmentation failed to do so. The algorithm was tested on thermal images that were segmented using the inter-variance thresholding. The thermal images contained human subjects as foreground with some background objects having similar thermal distribution as the subject. Informed consent was obtained from the subject that voluntarily took part in the study. The IEA was only tested on thermal images and failed when false background object was connected to the foreground after segmentation.

  8. Thermal conductivity of halide solid solutions: measurement and prediction.

    Science.gov (United States)

    Gheribi, Aïmen E; Poncsák, Sándor; St-Pierre, Rémi; Kiss, László I; Chartrand, Patrice

    2014-09-14

    The composition dependence of the lattice thermal conductivity in NaCl-KCl solid solutions has been measured as a function of composition and temperature. Samples with systematically varied compositions were prepared and the laser flash technique was used to determine the thermal diffusivity from 373 K to 823 K. A theoretical model, based on the Debye approximation of phonon density of state (which contains no adjustable parameters) was used to predict the thermal conductivity of both stoichiometric compounds and fully disordered solid solutions. The predictions obtained with the model agree very well with our measurement. A general method for predicting the thermal conductivity of different halide systems is discussed.

  9. Systems and methods for solar energy storage, transportation, and conversion utilizing photochemically active organometallic isomeric compounds and solid-state catalysts

    Science.gov (United States)

    Vollhardt, K. Peter C.; Segalman, Rachel A; Majumdar, Arunava; Meier, Steven

    2015-02-10

    A system for converting solar energy to chemical energy, and, subsequently, to thermal energy includes a light-harvesting station, a storage station, and a thermal energy release station. The system may include additional stations for converting the released thermal energy to other energy forms, e.g., to electrical energy and mechanical work. At the light-harvesting station, a photochemically active first organometallic compound, e.g., a fulvalenyl diruthenium complex, is exposed to light and is photochemically converted to a second, higher-energy organometallic compound, which is then transported to a storage station. At the storage station, the high-energy organometallic compound is stored for a desired time and/or is transported to a desired location for thermal energy release. At the thermal energy release station, the high-energy organometallic compound is catalytically converted back to the photochemically active organometallic compound by an exothermic process, while the released thermal energy is captured for subsequent use.

  10. Compound semiconductor device modelling

    CERN Document Server

    Miles, Robert

    1993-01-01

    Compound semiconductor devices form the foundation of solid-state microwave and optoelectronic technologies used in many modern communication systems. In common with their low frequency counterparts, these devices are often represented using equivalent circuit models, but it is often necessary to resort to physical models in order to gain insight into the detailed operation of compound semiconductor devices. Many of the earliest physical models were indeed developed to understand the 'unusual' phenomena which occur at high frequencies. Such was the case with the Gunn and IMPATI diodes, which led to an increased interest in using numerical simulation methods. Contemporary devices often have feature sizes so small that they no longer operate within the familiar traditional framework, and hot electron or even quantum­ mechanical models are required. The need for accurate and efficient models suitable for computer aided design has increased with the demand for a wider range of integrated devices for operation at...

  11. Magnetochemistry: Compounds and Concepts

    Science.gov (United States)

    Lueken, Heiko; Schilder, Helmut; Eifert, Thomas; Handrick, Klaus; Huening, Felix

    New materials in today's magnetochemistry are reviewed, among them spin-crossover compounds, single-molecule magnets, supramolecular magnetic materials, ferrofluids, and ferromagnetic nanocrystal superlattices, each with its specific application potential. Advanced computer programs are available which consider all relevant perturbations on the 'magnetic electrons' and allow, on the basis of precise measurement results, the evaluation of magnetic parameters, above all the exchange parameter J. By means of molecular, ionic, and metallic compounds the J values are discussed with respect to sign and magnitude on the basis of concepts which take into consideration overlap of magnetic orbitals (direct exchange, superexchange) and the conduction electron concentration. Finally, further developments in the field of magnetochemistry are prospected.

  12. Decay characteristics of once-through LWR and LMFBR spent fuels, high-level wastes, and fuel-assembly structural material wastes

    Energy Technology Data Exchange (ETDEWEB)

    Croff, A.G.; Alexander, C.W.

    1980-11-01

    The decay characteristics of spent fuel, high-level waste, and fuel-assembly structural material (cladding) waste are presented in the form of ORIGEN2 output tables for (1) a pressurized water reactor operating on a once-through cycle with low-enrichment uranium feed, (2) a boiling-water reactor operating on a once-through cycle with low-enrichment uranium feed, and (3) a liquid-metal fast breeder reactor being fueled with depleted uranium enriched with discharged light water reactor plutonium on a once-through basis. The decay characteristics given include the mass (g), radioactivity (Ci), thermal power (W), photon activity (photons/s and MeV/W-s in 18 energy groups), and neutron activity (neutrons/s) from (..cap alpha..,n) and spontaneous fission events. The first three characteristics are given for each element and for the principal nuclide contributors to the activation products, actinides, and fission products. Also included are a summary description of the ORIGEN2 reactor models that form the basis for the calculated results and a physical description of the fuel assemblies for the three reactors.

  13. Process for compound transformation

    KAUST Repository

    Basset, Jean-Marie

    2016-12-29

    Embodiments of the present disclosure provide for methods of using a catalytic system to chemically transform a compound (e.g., a hydrocarbon). In an embodiment, the method does not employ grafting the catalyst prior to catalysis. In particular, embodiments of the present disclosure provide for a process of hydrocarbon (e.g., C1 to C20 hydrocarbon) metathesis (e.g., alkane, olefin, or alkyne metathesis) transformation, where the process can be conducted without employing grafting prior to catalysis.

  14. Phenolic compounds in oats

    OpenAIRE

    Skoglund, Maria

    2008-01-01

    This research project examined how to treat raw oat material for oat-based food products in order to sustain or increase the levels of phenolic compounds. The focus was mainly on the avenanthramides, which are potentially health beneficial bioactive components found exclusively in oats. A proposed enzymatic decrease in avenanthramide levels when non heat-treated milled oats are steeped in water was investigated. The decrease was strongly suggested to be caused by a polyphenol oxidase. Althoug...

  15. A lubricating compound

    Energy Technology Data Exchange (ETDEWEB)

    Barchan, G.P.; Alekseyenko, V.A.; Bolotnikov, V.S.; Burlov, A.S.; Chigarenko, G.G.; Kogan, V.A.

    1982-01-01

    In a lubricating compound (SK), which contains petroleum or synthetic oil, a complex ether (SE) and an additive (Pr), in order to improve the loading, antifriction and antiwear properties, a complex ether of glycerin of the formula C/sub 3/H/sub 5/R/sub 3/, where R is C/sub 3/H/sub 7/C00, C/sub 17/H/sub 33/C00, is used and 2-(n-tololsulfamino)benzalaniline is used as the additive. The ratio of components in percent is: 2-(n-tololsulfamino)benzalanaline, 0.1 to 0.4; complex ether, 20 to 30 and petroleum or synthetic oil to 100. Oils of different chemical structure and physical and chemical properties are used for making the lubricating compound: vaseline, medicinal, industrial, instrumental MVP, vacuum VM-4 and polyethylsiloxane liquid 132-25. The oil is mixed with the complex ether and additive in the cited proportions with heating to 100 degrees C and intensive mixing. After cooling it is ready for use. The results of tests of the proposed lubricating compound in a facial friction machine for lubricating friction subasemblies of steel and a copper alloy showed significant improvements in properties.

  16. A lubricating compound

    Energy Technology Data Exchange (ETDEWEB)

    Barchan, G.P.; Boltnikov, V.S.; Bulgarevich, A.F.; Chigarenko, G.G.; Ponomarenko, A.G.

    1982-01-01

    In a known lubricating compound (SK) in order to improve the loading, antifriction and antiwear properties, a dicarbonic acid of a complex ether of azelaic acid of the formula (CH/sub 2/)/sub 7/(COOC/sub 2/H/sub 2//sub n+1/)/sub 2/, where n = 4 to 8, is additionally introduced as a complex ether (SE). 1-(2-oxy-1-naphthylazo)-2-naphthol-4-sulfo acid is introduced as an additive. The ratio of components in percent is: 1-(2-oxy-1-naphthylazo)-2-naphthol-4-sulfo acid 0.1 to 0.5 and complex ether, 20 to 30 and petroleum or synthetic oil (Ms) to 100 percent. Synthetic or petroleum oil of varying chemical structure and physical and chemical properties is used to prepare the lubricating compound: industrialnoye-20, vaseline, industrialnoye-50, instrumental MPV, vacuum MV-4 and polytehylsiloxanic liquid 32 to 25. The oil is mixed with the complex ether and the additive in the cited ratios with heating to 100 degrees and intensive mixing. After cooling, an oil ready for use is produced. The lubricating properties of the lubricating compound are studied in a facial friction (Tr) machine with a movable sample of St45.

  17. atmospheric volatile organic compounds

    Directory of Open Access Journals (Sweden)

    A. R. Koss

    2016-07-01

    organic compounds (VOCs that cannot be ionized with H3O+ ions (e.g., in a PTR-MS or H3O+ CIMS instrument. Here we describe the adaptation of a high-resolution time-of-flight H3O+ CIMS instrument to use NO+ primary ion chemistry. We evaluate the NO+ technique with respect to compound specificity, sensitivity, and VOC species measured compared to H3O+. The evaluation is established by a series of experiments including laboratory investigation using a gas-chromatography (GC interface, in situ measurement of urban air using a GC interface, and direct in situ measurement of urban air. The main findings are that (1 NO+ is useful for isomerically resolved measurements of carbonyl species; (2 NO+ can achieve sensitive detection of small (C4–C8 branched alkanes but is not unambiguous for most; and (3 compound-specific measurement of some alkanes, especially isopentane, methylpentane, and high-mass (C12–C15 n-alkanes, is possible with NO+. We also demonstrate fast in situ chemically specific measurements of C12 to C15 alkanes in ambient air.

  18. Antifungal compounds from cyanobacteria.

    Science.gov (United States)

    Shishido, Tânia K; Humisto, Anu; Jokela, Jouni; Liu, Liwei; Wahlsten, Matti; Tamrakar, Anisha; Fewer, David P; Permi, Perttu; Andreote, Ana P D; Fiore, Marli F; Sivonen, Kaarina

    2015-04-13

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.

  19. Antifungal Compounds from Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Tânia K. Shishido

    2015-04-01

    Full Text Available Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.

  20. Compound Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Kramer Gerhard

    2009-01-01

    Full Text Available Abstract This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom ( are derived for the degraded case with one receiver. Schemes to achieve the for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable is given for the general case.

  1. Thermal expansion of L-ascorbic acid

    Science.gov (United States)

    Nicolaï, B.; Barrio, M.; Tamarit, J.-Ll.; Céolin, R.; Rietveld, I. B.

    2017-04-01

    The specific volume of vitamin C has been investigated by X-ray powder diffraction as a function of temperature from 110 K up to complete degradation around 440 K. Its thermal expansion is relatively small in comparison with other organic compounds with an expansivity α v of 1.2(3) × 10-4 K-1. The structure consists of strongly bound molecules in the ac plane through a dense network of hydrogen bonds. The thermal expansion is anisotropic. Along the b axis, the expansion has most leeway and is about 10 times larger than in the other directions.

  2. Stabilization of organosilver(I) compounds, and their application in organic synthesis

    NARCIS (Netherlands)

    Westmijze, H.; Kleijn, H.; Vermeer, P.

    1979-01-01

    The favourable influence of lithium bromide on the thermal stability of organosilver(I) compounds is described. The stabilized silver(I) compounds have been brought into reaction with conjugated enynes; the regiochemistry of the reactions appears to depend on steric factors. A comparison is

  3. A composition for a carbon black compound

    Energy Technology Data Exchange (ETDEWEB)

    Mednikov, M.M.; Babyuk, V.N.; Kasatkin, G.P.; Khaykin, M.S.; Kozlov, L.A.; Stroyev, V.N.

    1983-01-01

    Paraffinylendiamine is additionally introduced into a known compound of a carbon black paste in order to increase the degree of blackness and the total stability. The ratio of components in parts is: carbon black 100; petroleum oil, 150 to 300; butadiene and 2-methyl-5-vinylpyridine copolymer, 0.1 to 10.0 and paraffinylendiamine, 0.5 to 5.0. Furnace, thermal, channel and acetylene carbon black with a specific Brunauer Emmett Teller surface of 10 to 1,000 square meters per grain, of high, medium and low structural states, modified by different compounds, for instance, 02, are used as the carbon black. Petroleum oil with a kinematic viscosity at 50 degrees of 15 to 40 centistokes (for instance, vaseline, transformer oil and so on) is used as the petroleum oil. The compound is prepared in the following manner. The petroleum oil, carbon black, copolymer and paraffinylendiamine are loaded into an apparatus with a mixer. The compound is mixed for two hours at 80 degrees, cooled to 25 degrees, unloaded and are ground in a color mill. The coloring force is determined in the following manner. The components are mixed for 30 minutes in a glue mixer, unloaded and is ground in the color mill ten times. One gram is taken off from each sample (Ob). The sample which contains no paraffinylendiamine is used as the control sample. One gram of each sample is mixed with ZnO until the color of the compound is transformed from shiny black to a gray matte (brightening). The ratio of the ZnO volume which went to brightening of the sample to the volume which went to brightening of the control sample (1.2 grams), multiplied by 100 percent is used as the coloring force. It is shown that the composition of the proposed carbon black paste has a high degree of blackness and a high aggregate stability.

  4. Ambazone-lipoic acid salt: Structural and thermal characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kacso, Irina [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Racz, Csaba-Pal; Santa, Szabolcs [Babes-Bolyai' University, Faculty of Chemistry, 11 Arany Janos street, Cluj-Napoca (Romania); Rus, Lucia [' Iuliu Hatieganu' University of Medicine and Pharmacy, Faculty of Pharmacy, 6 Louis Pasteur street, 400349 Cluj-Napoca (Romania); Dadarlat, Dorin; Borodi, Gheorghe [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Bratu, Ioan, E-mail: ibratu@gmail.com [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania)

    2012-12-20

    Highlights: Black-Right-Pointing-Pointer Salt of Ambazone with lipoic acid obtained by solvent-drop grinding. Black-Right-Pointing-Pointer Ambazone lipoate salt crystallizes in monoclinic system. Black-Right-Pointing-Pointer FTIR data suggest the deprotonation of the lipoic acid. Black-Right-Pointing-Pointer Thermal behaviour different of ambazone salt as compared to the starting compounds. - Abstract: A suitable method for increasing the solubility, dissolution rate and consequently the bioavailability of poor soluble acidic or basic drugs is their salt formation. The aim of this study is to investigate the structural and thermal properties of the compound obtained by solvent drop grinding (SDG) method at room temperature, starting from the 1:1 molar ratios of ambazone (AMB) and {alpha}-lipoic acid (LA). The structural characterization was performed with X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR). The thermal behaviour of the obtained compound (AMB{center_dot}LA) was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). The photopyroelectric calorimetry, in front detection configuration (FPPE), was applied to measure and compare the room temperature values of one dynamic thermal parameter (thermal effusivity) for starting and resulting compounds. Both structural and supporting calorimetric techniques pointed out a salt structure for AMB{center_dot}LA compound as compared to those of the starting materials.

  5. Thermal luminescence spectroscopy chemical imaging sensor.

    Science.gov (United States)

    Carrieri, Arthur H; Buican, Tudor N; Roese, Erik S; Sutter, James; Samuels, Alan C

    2012-10-01

    The authors present a pseudo-active chemical imaging sensor model embodying irradiative transient heating, temperature nonequilibrium thermal luminescence spectroscopy, differential hyperspectral imaging, and artificial neural network technologies integrated together. We elaborate on various optimizations, simulations, and animations of the integrated sensor design and apply it to the terrestrial chemical contamination problem, where the interstitial contaminant compounds of detection interest (analytes) comprise liquid chemical warfare agents, their various derivative condensed phase compounds, and other material of a life-threatening nature. The sensor must measure and process a dynamic pattern of absorptive-emissive middle infrared molecular signature spectra of subject analytes to perform its chemical imaging and standoff detection functions successfully.

  6. their use as Accelerator in Curing Process of Rubber Compounds

    Directory of Open Access Journals (Sweden)

    S. taghvaee

    2007-06-01

    Full Text Available In some special cases, rubber compounds with high amounts of unsaturated elastomer are recommended with organic sulfur donors instead of mineral sulfurs. In this condition, activated sulfur is produced in situ and curingprocess is facilitated without accelerators. Organic sulfur donor compounds have low thermal stability and in the vulcanization temperature produce free and activated sulfurs. The advantages of these compounds are:1. High effectiveness of curing agent in low quantities in rubber compounds manufacturing.2. Producing activated sulfurs in controlled condition and avoiding the over curing of rubber compounds.In this report the novel synthesis of some derivatives of diamino-disulfides which can be applied as sulfur donors in vulcanization of special rubber compounds is introduced. The key process is reaction of sulfurmonochloride with amines in petroleum ether as solvent in low temperature. Dithio-dimorpholine(DTDM, dithio-dipipyridyl (DTDP, dithio-bis dibutylamine (DTBDB and dithio-bisdiisopropyl amine (DTBDI were prepared according to this method. All products thus obtained were characterized by 1H and 13C-NMR spectroscopies. The effects of accelerating and sulfur donoring of all prepared agents were detected in rubber compounds with natural and synthetic rubber bases. All physical, chemical, reological and mechanical properties of rubber compounds based on prepared sulfur donors were characterized.

  7. Influence of heat treatment on antioxidant capacity and (poly)phenolic compounds of selected vegetables

    OpenAIRE

    Juaniz, I. (Isabel); Ludwig, I.A. (Iziar A.); Huarte, E; Pereira-Caro, G.; Moreno-Rojas, J.M.; Cid, C. (Concepción); Peña, M.P. (María Paz) de

    2016-01-01

    The impact of cooking heat treatments (frying in olive oil, frying in sunflower oil and griddled) on the antioxidant capacity and (poly)phenolic compounds of onion, green pepper and cardoon, was evaluated. The main compounds were quercetin and isorhamnetin derivates in onion, quercetin and luteolin derivates in green pepper samples, and chlorogenic acids in cardoon. All heat treatments tended to increase the concentration of phenolic compounds in vegetables suggesting a thermal destruction of...

  8. Solar Thermal Energy Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Pitsenbarger, J. [eds.

    1996-02-01

    Solar Thermal Energy Technology (PST) announces on a bimonthly basis the current worldwide research and development information that would expand the technology base required for the advancement of solar thermal systems as a significant energy resource.

  9. Ouellette Thermal Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Thermal Test Facility is a joint Army/Navy state-of-the-art facility (8,100 ft2) that was designed to:Evaluate and characterize the effect of flame and thermal...

  10. Offset Compound Gear Drive

    Science.gov (United States)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  11. Boronated porphyrin compounds

    Science.gov (United States)

    Kahl, Stephen B.; Koo, Myoung-Seo

    1992-01-01

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  12. Electric Motor Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    Thermal management enables more efficient and cost-effective motors. This Annual Merit Review presentation describes the technical accomplishments and progress in electric motor thermal management R&D over the last year. This project supports a broad industry demand for data, analysis methods, and experimental techniques to improve and better understand motor thermal management.

  13. Thermal Performance Benchmarking (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, G.

    2014-11-01

    This project will benchmark the thermal characteristics of automotive power electronics and electric motor thermal management systems. Recent vehicle systems will be benchmarked to establish baseline metrics, evaluate advantages and disadvantages of different thermal management systems, and identify areas of improvement to advance the state-of-the-art.

  14. Synthesis, structural and electrical characterizations of thermally ...

    African Journals Online (AJOL)

    The cross-planar i-v characteristics curves of Cu2SnS3 films were non-Ohmic while in-planar i-v characteristic curves were Ohmic. The electrical resistivity of the deposited Cu2SnS3 film is 2.55 x 10-3 Ωcm. The conductivity is in the order of 103 Ω-1cm-1. Key words: Ternary compound, microscopic glass substrate, Thermal ...

  15. Frequency effects in compound production

    NARCIS (Netherlands)

    Bien, H.; Levelt, W.J.M.; Baayen, R.H.

    2005-01-01

    Four experiments investigated the role of frequency information in compound production by independently varying the frequencies of the first and second constituent as well as the frequency of the compound itself. Pairs of Dutch noun-noun compounds were selected such that there was a maximal contrast

  16. Organometallic compounds in the environment

    National Research Council Canada - National Science Library

    Craig, P. J

    2003-01-01

    ... of Organometallic Species in the Environment 20 1.10 Stability of Organometallic Compounds in Biological Systems 1.11 G eneral Comments on the Toxicities of Organometallic Compounds 22 1.12 General Considerations on Environmental R eactivity of Organometallic Compounds 24 1.13 Microbial Biotransformation of Metals and M etalloids 25 1.13.1 Introduction 25 1...

  17. Molecular modeling of inorganic compounds

    National Research Council Canada - National Science Library

    Comba, Peter; Hambley, Trevor W; Martin, Bodo

    2009-01-01

    ... mechanics to inorganic and coordination compounds. Initially, simple metal complexes were modeled, but recently the field has been extended to include organometallic compounds, catalysis and the interaction of metal ions with biological macromolecules. The application of molecular mechanics to coordination compounds is complicated by the numbe...

  18. Theoretical Study of the Compound Parabolic Trough Solar Collector

    Directory of Open Access Journals (Sweden)

    Dr. Subhi S. Mahammed

    2012-06-01

    Full Text Available Theoretical design of compound parabolic trough solar collector (CPC without tracking is presented in this work. The thermal efficiency is obtained by using FORTRAN 90 program. The thermal efficiency is between (60-67% at mass flow rate between (0.02-0.03 kg/s at concentration ratio of (3.8 without need to tracking system.The total and diffused radiation is calculated for Tikrit city by using theoretical equations. Good agreement between present work and the previous work.

  19. Semiconducting III-V compounds

    CERN Document Server

    Hilsum, C; Henisch, Heinz R

    1961-01-01

    Semiconducting III-V Compounds deals with the properties of III-V compounds as a family of semiconducting crystals and relates these compounds to the monatomic semiconductors silicon and germanium. Emphasis is placed on physical processes that are peculiar to III-V compounds, particularly those that combine boron, aluminum, gallium, and indium with phosphorus, arsenic, and antimony (for example, indium antimonide, indium arsenide, gallium antimonide, and gallium arsenide).Comprised of eight chapters, this book begins with an assessment of the crystal structure and binding of III-V compounds, f

  20. Thermal Management and Thermal Protection Systems

    Science.gov (United States)

    Hasnain, Aqib

    2016-01-01

    During my internship in the Thermal Design Branch (ES3), I contributed to two main projects: i) novel passive thermal management system for future human exploration, ii) AVCOAT undercut thermal analysis. i) As NASA prepares to further expand human and robotic presence in space, it is well known that spacecraft architectures will be challenged with unprecedented thermal environments. Future exploration activities will have the need of thermal management systems that can provide higher reliability, mass and power reduction and increased performance. In an effort to start addressing the current technical gaps the NASA Johnson Space Center Passive Thermal Discipline has engaged in technology development activities. One of these activities was done through an in-house Passive Thermal Management System (PTMS) design for a lunar lander. The proposed PTMS, functional in both microgravity and gravity environments, consists of three main components: a heat spreader, a novel hybrid wick Variable Conductance Heat Pipe (VCHP), and a radiator. The aim of this PTMS is to keep electronics on a vehicle within their temperature limits (0 and 50 C for the current design) during all mission phases including multiple lunar day/night cycles. The VCHP was tested to verify its thermal performance. I created a thermal math model using Thermal Desktop (TD) and analyzed it to predict the PTMS performance. After testing, the test data provided a means to correlate the thermal math model. This correlation took into account conduction and convection heat transfer, representing the actual benchtop test. Since this PTMS is proposed for space missions, a vacuum test will be taking place to provide confidence that the system is functional in space environments. Therefore, the model was modified to include a vacuum chamber with a liquid nitrogen shroud while taking into account conduction and radiation heat transfer. Infrared Lamps were modelled and introduced into the model to simulate the sun

  1. Structure Modification of an Active Azo-Compound as a Route to New Antimicrobial Compounds

    Directory of Open Access Journals (Sweden)

    Simona Concilio

    2017-05-01

    Full Text Available Some novel (phenyl-diazenylphenols 3a–g were designed and synthesized to be evaluated for their antimicrobial activity. A previously synthesized molecule, active against bacteria and fungi, was used as lead for modifications and optimization of the structure, by introduction/removal or displacement of hydroxyl groups on the azobenzene rings. The aim of this work was to evaluate the consequent changes of the antimicrobial activity and to validate the hypothesis that, for these compounds, a plausible mechanism could involve an interaction with protein receptors, rather than an interaction with membrane. All newly synthesized compounds were analyzed by 1H-NMR, DSC thermal analysis and UV-Vis spectroscopy. The in vitro minimal inhibitory concentrations (MIC of each compound was determined against Gram-positive and Gram-negative bacteria and Candida albicans. Compounds 3b and 3g showed the highest activity against S. aureus and C. albicans, with remarkable MIC values of 10 µg/mL and 3 µg/mL, respectively. Structure-activity relationship studies were capable to rationalize the effect of different substitutions on the phenyl ring of the azobenzene on antimicrobial activity.

  2. Quantum Thermal Transistor.

    Science.gov (United States)

    Joulain, Karl; Drevillon, Jérémie; Ezzahri, Younès; Ordonez-Miranda, Jose

    2016-05-20

    We demonstrate that a thermal transistor can be made up with a quantum system of three interacting subsystems, coupled to a thermal reservoir each. This thermal transistor is analogous to an electronic bipolar one with the ability to control the thermal currents at the collector and at the emitter with the imposed thermal current at the base. This is achieved by determining the heat fluxes by means of the strong-coupling formalism. For the case of three interacting spins, in which one of them is coupled to the other two, that are not directly coupled, it is shown that high amplification can be obtained in a wide range of energy parameters and temperatures. The proposed quantum transistor could, in principle, be used to develop devices such as a thermal modulator and a thermal amplifier in nanosystems.

  3. Flavour Compounds in Fungi

    DEFF Research Database (Denmark)

    Ravasio, Davide Antonio

    from the catabolism of amino acids. These compounds are produced by the Ehrlich pathway. The conversion of amino acids into aroma alcohols is accomplished by three enzymatic steps: i) a transamination, ii) a decarboxylation and iii) a dehydration reaction. The transaminase and decarboxylase enzymes...... and 2-phenylacetate. The last part of this thesis presents the initial characterization of twenty non-conventional yeasts (NCY) and their potential application in fermentative processes. These strains have been selected as they have been previously isolated from various fermented food sources....... This selection of strains was used in fermentations with the aim of identifying new interesting flavour producers. Fermentation profiles, volatile analyses, off-flavour identification and resistance to osmotic/oxidative stress have been addressed to highlight new candidates to use for industrial applications...

  4. Flavour Compounds in Fungi

    DEFF Research Database (Denmark)

    Ravasio, Davide Antonio

    provides a tool for the prediction of volatile production in other Saccharomyces sensu stricto species. It can be used to screen a large number of strains for their flavour production within a short time and with low costs and effort. In Ashbya single mutations in the ARO genes led to a strong reduction...... region is directly regulated by the ScAro80 transcription factor. This interaction has been used to create a lacZ-reporter system to correlate the formation of two volatile compounds, 2- phenylethanol and 2-phenylethyl acetate in yeast with ARO9 expression levels. This indirect genetic assay also...... in volatile production, especially in the amount of isoamyl alcohol and 2-phenylethanol. In contrast, the overexpression of the transcriptional regulator AgARO80 did only increase the level of isoamyl alcohol but did not enhance the 2-phenylethanol yield. Promoter analyses of the ARO genes in A. gossypii...

  5. Study of Selected Composites Copper Concentrate-Plastic Waste Using Thermal Analysis

    Science.gov (United States)

    Szyszka, Danuta

    2017-12-01

    The paper presents thermal analysis of selected composites (copper concentrate, plastic waste) in two stages. The first stage consisted in thermogravimetric analysis and differential thermal analysis on the applied plastic waste and copper concentrate, and subsequently, a comparative study has been carried out on products obtained, constituting composites of those materials. As a result of analyses, it was found that up to ca. 400 °C composites show high thermal stability, whereas above that temperature, a thermal decomposition of the composite occurs, resulting in emissions of organic compounds, i.e. hydrocarbon compounds and organic oxygenate derivatives.

  6. Lanthanide phosphonates: Synthesis, thermal stability and magnetic characterization

    Energy Technology Data Exchange (ETDEWEB)

    Amghouz, Z., E-mail: amghouz.uo@uniovi.es [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Garcia, J.R.; Garcia-Granda, S. [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Clearfield, A. [Department of Chemistry, Texas A and M University, College Station, TX 77842-3012 (United States); Rodriguez Fernandez, J.; Pedro, I. de [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Report of the complete series of lanthanide 1,4-phenylbis(phosphonate). Black-Right-Pointing-Pointer Synthesis under conventional hydrothermal synthesis or microwave-assisted hydrothermal synthesis. Black-Right-Pointing-Pointer Cation size is the key factor for the structural and particles size variations. Black-Right-Pointing-Pointer Thermal behaviour is characterized by unusual very high thermal stability. - Abstract: Series of novel organic-inorganic hybrids materials based on trivalent lanthanides (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and 1,4-phenylbis(phosphonate) obtained under hydrothermal conditions either by oven heat or microwave irradiation. The anhydrous compounds containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho, are isostructural. However, the compounds based on Y, Er, Tm, Yb, and Lu are hydrated and their structures have not yet been solved. The series of compounds are characterized by PXRD, TEM, SEM-EDX and thermal analyses (TG-MS and DSC). TEM study show a variable particles size with a minimum mean-particle size of ca. 30 nm. These compounds exhibit unusual very high thermal stability. The size of particles and the thermal stability are depending on lanthanide(III) cation features. All the investigated materials show paramagnetic behaviour. The magnetic susceptibility data follow a Curie-Weiss laws with paramagnetic effective moments in good agreement with those expected for Ln{sup 3+} free ions.

  7. High-Thermal-Conductivity Fabrics

    Science.gov (United States)

    Chibante, L. P. Felipe

    2012-01-01

    Heat management with common textiles such as nylon and spandex is hindered by the poor thermal conductivity from the skin surface to cooling surfaces. This innovation showed marked improvement in thermal conductivity of the individual fibers and tubing, as well as components assembled from them. The problem is centered on improving the heat removal of the liquid-cooled ventilation garments (LCVGs) used by astronauts. The current design uses an extensive network of water-cooling tubes that introduces bulkiness and discomfort, and increases fatigue. Range of motion and ease of movement are affected as well. The current technology is the same as developed during the Apollo program of the 1960s. Tubing material is hand-threaded through a spandex/nylon mesh layer, in a series of loops throughout the torso and limbs such that there is close, form-fitting contact with the user. Usually, there is a nylon liner layer to improve comfort. Circulating water is chilled by an external heat exchanger (sublimator). The purpose of this innovation is to produce new LCVG components with improved thermal conductivity. This was addressed using nanocomposite engineering incorporating high-thermalconductivity nanoscale fillers in the fabric and tubing components. Specifically, carbon nanotubes were added using normal processing methods such as thermoplastic melt mixing (compounding twin screw extruder) and downstream processing (fiber spinning, tubing extrusion). Fibers were produced as yarns and woven into fabric cloths. The application of isotropic nanofillers can be modeled using a modified Nielsen Model for conductive fillers in a matrix based on Einstein s viscosity model. This is a drop-in technology with no additional equipment needed. The loading is limited by the ability to maintain adequate dispersion. Undispersed materials will plug filtering screens in processing equipment. Generally, the viscosity increases were acceptable, and allowed the filled polymers to still be

  8. Azo group containing compounds: investigation of the decay mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Franzke, D.; Kritzenberger, J.; Kunz, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    We investigated compounds containing the N=N-X (X=S,P,N{sub 3}) group which are potential candidates for microstructuring by photoresist technology or by photoablation. To elucidate the mechanism of thermal decomposition and photolysis we used infrared and UV spectroscopy, respectively, in solution as well as in the solid state. In this article we describe photolytic and thermolytic properties of one representative molecule for each of three substance classes: diazosulfides, azophosphonates and pentazadienes. (author) 4 figs., 4 refs.

  9. Zeolite and zeotype-catalysed transformations of biofuranic compounds

    DEFF Research Database (Denmark)

    Li, Hu; Yang, Song; Riisager, Anders

    2016-01-01

    with tuneable acidity, good thermal stability and shape-selectivity have recently emerged as promising solid catalysts, exhibiting superior catalytic performance to other heterogeneous catalysts. This review focuses on the synthesis of biomass-derived furanic compounds catalysed by zeolitic materials, firstly...... introducing zeolite-catalysed hydrolysis of di-, oligo- and polysaccharides and isomerization reactions of monomeric sugars. Subsequently, the catalytic dehydration reactions of hexoses and pentoses to obtain HMF and furfural are reported. Particularly, a variety of reaction pathways towards upgrading...

  10. Compounding in synthetic aperture imaging

    DEFF Research Database (Denmark)

    Hansen, J. M.; Jensen, J. A.

    2012-01-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic...... property of how the compound images are constructed using synthetic aperture data and an improvement compared with how spatial compounding is obtained using conventional methods. The synthetic aperture compound images are created by exploiting the linearity of delay-and-sum beamformation for data collected...... from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from...

  11. Optimizing Synthetic Aperture Compound Imaging

    DEFF Research Database (Denmark)

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-01-01

    Spatial compound images are constructed from synthetic aperture data acquired using a linear phased-array transducer. Compound images of wires, tissue, and cysts are created using a method, which allows both transmit and receive compounding without any loss in temporal resolution. Similarly...... to conventional imaging, the speckle reduction achieved by spatial compounding comes at the cost of a reduced detail resolution and a compromise must be made. Using a performance indicator, which can be measured from an image of a phantom without cysts, it is demonstrated how a compromise can be made, which...... is optimal for lesion detection. Synthetic aperture data are acquired from unfocused emissions and 154 compound images are constructed by synthesizing different aperture configurations with more or less compounding, all maintaining a constant resolution across depth corresponding to an f-number of 2...

  12. Pluto's Nonvolatile Chemical Compounds

    Science.gov (United States)

    Grundy, William M.; Binzel, Richard; Cook, Jason C.; Cruikshank, Dale P.; Dalle Ore, Cristina M.; Earle, Alissa M.; Ennico, Kimberly; Jennings, Donald; Howett, Carly; Kaiser, Ralf-Ingo; Linscott, Ivan; Lunsford, A. W.; Olkin, Catherine B.; Parker, Alex Harrison; Parker, Joel Wm.; Philippe, Sylvain; Protopapa, Silvia; Quirico, Eric; Reuter, D. C.; Schmitt, Bernard; Singer, Kelsi N.; Spencer, John R.; Stansberry, John A.; Stern, S. Alan; Tsang, Constantine; Verbiscer, Anne J.; Weaver, Harold A.; Weigle, G. E.; Young, Leslie

    2016-10-01

    Despite the migration of Pluto's volatile ices (N2, CO, and CH4) around the surface on seasonal timescales, the planet's non-volatile materials are not completely hidden from view. They occur in a variety of provinces formed over a wide range of timescales, including rugged mountains and chasms, the floors of mid-latitude craters, and an equatorial belt of especially dark and reddish material typified by the informally named Cthulhu Regio. NASA's New Horizons probe observed several of these regions at spatial resolutions as fine as 3 km/pixel with its LEISA imaging spectrometer, covering wavelengths from 1.25 to 2.5 microns. Various compounds that are much lighter than the tholin-like macromolecules responsible for the reddish coloration, but that are not volatile at Pluto surface temperatures such as methanol (CH3OH) and ethane (C2H6) have characteristic absorption bands within LEISA's wavelength range. This presentation will describe their geographic distributions and attempt to constrain their origins. Possibilities include an inheritance from Pluto's primordial composition (the likely source of H2O ice seen on Pluto's surface) or ongoing production from volatile precursors through photochemistry in Pluto's atmosphere or through radiolysis on Pluto's surface. New laboratory data inform the analysis.This work was supported by NASA's New Horizons project.

  13. Thermal Imaging in Aviation

    Directory of Open Access Journals (Sweden)

    Marek Štumper

    2015-10-01

    Full Text Available This article focuses on the use of thermal imaging in aviation. In the never ending pursuit of lower costs, the Thermal Imaging offers shorter inspection times thanks to its application in aircraft inspections and can reduce the number of costly goarounds using the Enhanced Vision System, which also increases safety in one of the most dangerous parts of flight. Thermal Imaging also offers solutions for Airport Perimeter Security and it can be used for construction of ground surveillance system.

  14. Thermal waveguide OPO.

    Science.gov (United States)

    Lin, S T; Lin, Y Y; Wang, T D; Huang, Y C

    2010-01-18

    We report a mid-infrared, CW singly resonant optical parametric oscillator (OPO) with a thermally induced waveguide in its gain crystal. We measured a numerical aperture of 0.0062 for the waveguide at 80-W intracavity power at 3.2 microm. This thermal-guiding effect benefits to the stable operation of an OPO and improves the parametric conversion efficiency by more than a factor of two when compared with that without thermal guiding.

  15. Thermal Hyperbolic Metamaterials

    OpenAIRE

    Guo, Yu; Jacob, Zubin

    2013-01-01

    We explore the near-field radiative thermal energy transfer properties of hyperbolic metamaterials. The presence of unique electromagnetic states in a broad bandwidth leads to super-planckian thermal energy transfer between metamaterials separated by a nano-gap. We consider practical phonon-polaritonic metamaterials for thermal engineering in the mid-infrared range and show that the effect exists in spite of the losses, absorption and finite unit cell size. For thermophotovoltaic energy conve...

  16. Identifiability of Compound Poisson Distributions

    OpenAIRE

    Xekalaki, Evdokia; Panaretos, John

    1983-01-01

    Compound Poisson distributions (CPD's) are frequently used as alternatives in studying situations where a simple Poisson model is found inadequate to describe. In this paper an attempt is made to identify compound Poisson distributions when it is known that the conditional distribution of two random variables (r.v.'s) is compound binomial. Some interesting special cases and their application to accident theory are discussed.

  17. Phenolic compounds in Ecuadorian fruits

    OpenAIRE

    Vasco, Catalina

    2009-01-01

    A group of eighteen fruits cultivated in Ecuador were evaluated for their total soluble phenolic compounds and antioxidant activity and attempts were made to identify the group and content of phenolic compounds responsible for the antioxidant activity. In terms of total phenolic content, three groups (with 1000 mg gallic acid equivalents/100 g FW) were clearly distinguishable. RP-HPLC-DAD and/or LC-MS/MS were used to study the phenolic compounds in four Rosaceae fruits (Andean blackberry, str...

  18. Building Thermal Models

    Science.gov (United States)

    Peabody, Hume L.

    2017-01-01

    This presentation is meant to be an overview of the model building process It is based on typical techniques (Monte Carlo Ray Tracing for radiation exchange, Lumped Parameter, Finite Difference for thermal solution) used by the aerospace industry This is not intended to be a "How to Use ThermalDesktop" course. It is intended to be a "How to Build Thermal Models" course and the techniques will be demonstrated using the capabilities of ThermalDesktop (TD). Other codes may or may not have similar capabilities. The General Model Building Process can be broken into four top level steps: 1. Build Model; 2. Check Model; 3. Execute Model; 4. Verify Results.

  19. Thermal microactuator dimension analysis

    Science.gov (United States)

    Azman, N. D.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

    2017-09-01

    The focus of this study was to analyse the stress and thermal flow of thermal microactuator with different type of materials and parameter using COMSOL Multiphysics software. Simulations were conducted on the existing thermal actuator and integrated it to be more efficient, low cost and low power consumption. In this simulation, the U-shaped actuator was designed and five different materials of the microactuator were studied. The result showed that Si Polycrystalline was the most suitable material used to produce thermal actuator for commercialization.

  20. Thermal Performance Benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xuhui; Moreno, Gilbert; Bennion, Kevin

    2016-06-07

    The goal for this project is to thoroughly characterize the thermal performance of state-of-the-art (SOA) in-production automotive power electronics and electric motor thermal management systems. Information obtained from these studies will be used to: evaluate advantages and disadvantages of different thermal management strategies; establish baseline metrics for the thermal management systems; identify methods of improvement to advance the SOA; increase the publicly available information related to automotive traction-drive thermal management systems; help guide future electric drive technologies (EDT) research and development (R&D) efforts. The thermal performance results combined with component efficiency and heat generation information obtained by Oak Ridge National Laboratory (ORNL) may then be used to determine the operating temperatures for the EDT components under drive-cycle conditions. In FY16, the 2012 Nissan LEAF power electronics and 2014 Honda Accord Hybrid power electronics thermal management system were characterized. Comparison of the two power electronics thermal management systems was also conducted to provide insight into the various cooling strategies to understand the current SOA in thermal management for automotive power electronics and electric motors.

  1. Theory of thermal stresses

    CERN Document Server

    Boley, Bruno A

    1997-01-01

    Highly regarded text presents detailed discussion of fundamental aspects of theory, background, problems with detailed solutions. Basics of thermoelasticity, heat transfer theory, thermal stress analysis, more. 1985 edition.

  2. Natural compounds with herbicidal activity

    Directory of Open Access Journals (Sweden)

    Pasquale Montemurro

    2011-02-01

    Full Text Available Research about phytotoxic activity of natural compounds could lead both to find new herbicidal active ingredients and to plan environmental friendly weed control strategies. Particularly, living organisms could be a source of compounds that are impossible, for their complexity, to synthesize artificially. More over, they could have alternative sites of action respect to the known chemical herbicides and, due to their origin, they should be more environmental safe. Many living organism, such as bacteria, fungi, insects, lichens and plants, are able to produce bioactive compounds. They generally are secondary metabolites or simply waste molecules. In this paper we make a review about these compounds, highlighting potential and constraints.

  3. Variable pressure thermal insulating jacket

    Science.gov (United States)

    Nelson, Paul A.; Malecha, Richard F.; Chilenskas, Albert A.

    1994-01-01

    A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

  4. Antimicrobial compounds in tears.

    Science.gov (United States)

    McDermott, Alison M

    2013-12-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Thermal Properties of Anionic Polyurethane Composition for Leather Finishing

    Directory of Open Access Journals (Sweden)

    Olga KOVTUNENKO

    2016-09-01

    Full Text Available Thermal properties of anionic polyurethane composition mixed with collagen product and hydrophilic sodium form of montmorillonite for use in the finishing of leather were studied by thermogravimetric method. The thermal indices of processes of thermal and thermo-oxidative destruction depending on the polyurethane composition were determined. The influence of anionic polyurethane composition on thermal behavior of chromium tanned gelatin films that imitate the leather were studied. APU composition with natural compounds increases their thermal stability both in air and in nitrogen atmosphere due to the formation of additional bonds between active groups of APU, protein and chrome tanning agent as the result of chemical reactions between organic and inorganic parts with the new structure formation.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.10043

  6. Processing and properties of PCL/cotton linter compounds

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, Elieber Barros; Franca, Danyelle Campos; Morais, Dayanne Diniz de Souza; Araujo, Edcleide Maria [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Rosa, Morsyleide de Freitas; Morais, Joao Paulo Saraiva [Embrapa Tropical Agroindustia, Fortaleza, CE (Brazil); Wellen, Renate Maria Ramos, E-mail: wellen.renate@gmail.com [Universidade Federal da Paraiaba (UFPB), Joao Pessoa, PB (Brazil)

    2017-03-15

    Biodegradable compounds of poly(ε-caprolactone) (PCL)/ cotton linter were melting mixed with filling content ranging from 1% to 5% w/w. Cotton linter is an important byproduct of textile industry; in this work it was used in raw state and after acid hydrolysis. According to the results of torque rheometry no decaying of viscosity took place during compounding, evidencing absence of breaking down in molecular weight. The thermal stability increased by 20% as observed in HDT for PCL/cotton nanolinter compounds. Adding cotton linter to PCL did not change its crystalline character as showed by XRD; however an increase in degree of crystallinity was observed by means of DSC. From mechanical tests in tension was observed an increase in ductility of PCL, and from mechanical tests in flexion an increase in elastic modulus upon addition of cotton linter, whereas impact strength presented lower values for PCL/cotton linter and PCL/cotton nanolinter compounds. SEM images showed that PCL presents plastic fracture and cotton linter has an interlacing fibril structure with high L/D ratio, which are in agreement with matrix/fibril morphology observed for PCL/cotton linter compounds. PCL/cotton linter compounds made in this work cost less than neat PCL matrix and presented improved properties making feasible its commercial use. (author)

  7. Enhancing Thermal Conductivity of Hexagonal Boron Nitride Filled Thermoplastics for Thermal Interface Management

    Science.gov (United States)

    Prindl, John

    Hexagonal Boron Nitride has been shown to enhance thermal conductivity in polymer composites more so than conventional ceramic fillers. However, to see a significant increase in thermal conductivity a high loading level of the advanced ceramic is often needed which can have an adverse effect on the mechanical behavior of the composite part. Applications for thermal management using thermal interface materials (TIM) continue to grow with thermoplastic injection molded parts emerging as an area for market growth. There is a growing need for published technical data in this particular area of application. In the current study, the thermal conductivity and mechanical behavior of hexagonal Boron Nitride (hBN) loaded thermoplastic composites is investigated. The main objectives of this work is produce a novel data package which illustrates the effects of hBN, loaded at high concentrations, across several different thermoplastic resins with the ultimate goal being to find a desirable formulation for specific thermal management applications. The desired properties for such applications being high thermal conductivity and high electrical resistivity with a minimal decrease in mechanical properties. Hexagonal BN cooling filler agglomerates were compounded into polypropylene (PP), nylon-6 (PA-6), and thermoplastic elastomer (TPE) via twin-screw extruder at 3 different loading levels. Injection molded samples were produced and characterized to show varying degrees of thermal conductivity and mechanical strength. Results from this research showed that in all cases, the thermal conductivity increased with increasing levels of hBN addition. The largest increases in thermal conductivity were seen in the PA-6 and TPE systems with the possible indication of exceeding the percolation threshold in the TPE system. This is hypothesized to occur due to the preferential migration of hBN to form conduction pathways around the elastomeric domains in the TPE matrix. Though TPE produced

  8. Thermoelectric transport in rare-earth compounds

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Ulrike

    2007-07-01

    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce{sub 3}Rh{sub 4}Sn{sub 13} are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu{sub 1-x}Yb{sub x}Rh{sub 2}Si{sub 2} and Ce{sub x}La{sub 1-x}Ni{sub 2}Ge{sub 2} by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  9. A thermal ground cloak

    Science.gov (United States)

    Yang, Tianzhi; Wu, Qinghe; Xu, Weikai; Liu, Di; Huang, Lujun; Chen, Fei

    2016-02-01

    The thermal cloak has been a long-standing scientific dream of researchers and engineers. Recently thermal metamaterials with man-made micro-structure have been presented based on the principle of transformation optics (TO). This new concept has received considerable attention, which is a powerful tool for manipulating heat flux in thermal imaging systems. However, the inherent material singularity has long been a captivation of experimental realization. As an alternative method, the scattering-cancellation-based cloak (or bi-layer thermal cloak) has been presented to remove the singularity for achieving the same cloaking performance. Nevertheless, such strategy needs prerequisite knowledge (geometry and conductivity) of the object to be cloaked. In this paper, a new thermal ground cloak is presented to overcome the limitations. The device is designed, fabricated and measured to verify the thermal cloaking performance. We experimentally show that the remarkably low complexity of the device can fully and effectively be manipulated using realizable transformation thermal devices. More importantly, this thermal ground cloak is designed to exclude heat flux without knowing the information of the cloaked object.

  10. Power Electronics Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-07

    Thermal modeling was conducted to evaluate and develop thermal management strategies for high-temperature wide-bandgap (WBG)-based power electronics systems. WBG device temperatures of 175 degrees C to 250 degrees C were modeled under various under-hood temperature environments. Modeling result were used to identify the most effective capacitor cooling strategies under high device temperature conditions.

  11. Thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor)

    2011-01-01

    A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

  12. Conceptual thermal design

    NARCIS (Netherlands)

    Strijk, R.

    2008-01-01

    Present thermal design tools and methods insufficiently support the development of structural concepts engaged by typical practicing designers. Research described in this thesis identifies the main thermal design problems in practice. In addition, models and methods are developed that support an

  13. Thermal energy storage

    Science.gov (United States)

    1980-01-01

    The planning and implementation of activities associated with lead center management role and the technical accomplishments pertaining to high temperature thermal energy storage subsystems are described. Major elements reported are: (1) program definition and assessment; (2) research and technology development; (3) industrial storage applications; (4) solar thermal power storage applications; and (5) building heating and cooling applications.

  14. Thermal flow micro sensors

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow

  15. High Thermal Conductivity Materials

    CERN Document Server

    Shinde, Subhash L

    2006-01-01

    Thermal management has become a ‘hot’ field in recent years due to a need to obtain high performance levels in many devices used in such diverse areas as space science, mainframe and desktop computers, optoelectronics and even Formula One racing cars! Thermal solutions require not just taking care of very high thermal flux, but also ‘hot spots’, where the flux densities can exceed 200 W/cm2. High thermal conductivity materials play an important role in addressing thermal management issues. This volume provides readers a basic understanding of the thermal conduction mechanisms in these materials and discusses how the thermal conductivity may be related to their crystal structures as well as microstructures developed as a result of their processing history. The techniques for accurate measurement of these properties on large as well as small scales have been reviewed. Detailed information on the thermal conductivity of diverse materials including aluminum nitride (AlN), silicon carbide (SiC), diamond, a...

  16. Paradoxes of Thermal Radiation

    Science.gov (United States)

    Besson, U.

    2009-01-01

    This paper presents an analysis of the thermal behaviour of objects exposed to a solar-type flux of thermal radiation. It aims to clarify certain apparent inconsistencies between theory and observation, and to give a detailed exposition of some critical points that physics textbooks usually treat in an insufficient or incorrect way. In particular,…

  17. Thermal Activated Envelope

    DEFF Research Database (Denmark)

    Foged, Isak Worre; Pasold, Anke

    2015-01-01

    search procedure, the combination of materials and their bonding temperature is found in relation to the envelope effect on a thermal environment inside a defined space. This allows the designer to articulate dynamic composites with time-based thermal functionality, related to the material dynamics...

  18. II-VI semiconductor compounds

    CERN Document Server

    1993-01-01

    For condensed matter physicists and electronic engineers, this volume deals with aspects of II-VI semiconductor compounds. Areas covered include devices and applications of II-VI compounds; Co-based II-IV semi-magnetic semiconductors; and electronic structure of strained II-VI superlattices.

  19. The Electrochemistry of Organophosphorus Compounds.

    Science.gov (United States)

    1988-01-20

    the exclusive vlide product. Furthermore, carbonvl compounds were added to the electrolyses to react with the electrochemically-generated ylides via...Howard Hargis Electrolyses of the trivalent organophosphorus compounds of the type Ph 3 x P(PhO) x (x=0,2,3) in dry acetonitrile saturated with oxygen

  20. Process for demethylating dimethylsulfonium compounds

    NARCIS (Netherlands)

    Hansen, Theo; van der Maarel, Marc

    1998-01-01

    PCT No. PCT/EP94/01640 Sec. 371 Date Nov. 14, 1995 Sec. 102(e) Date Nov. 14, 1995 PCT Filed May 16, 1994 PCT Pub. No. WO94/26918 PCT Pub. Date Nov. 24, 1994Process for preparing S-methylmercapto and mercapto compounds comprising the step of demethylating a dimethylsulfonium compound of formula I to

  1. Radiative Bistability and Thermal Memory

    Science.gov (United States)

    Kubytskyi, Viacheslav; Biehs, Svend-Age; Ben-Abdallah, Philippe

    2014-08-01

    We predict the existence of a thermal bistability in many-body systems out of thermal equilibrium which exchange heat by thermal radiation using insulator-metal transition materials. We propose a writing-reading procedure and demonstrate the possibility to exploit the thermal bistability to make a volatile thermal memory. We show that this thermal memory can be used to store heat and thermal information (via an encoding temperature) for arbitrary long times. The radiative thermal bistability could find broad applications in the domains of thermal management, information processing, and energy storage.

  2. Battery Pack Thermal Design

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, Ahmad

    2016-06-14

    This presentation describes the thermal design of battery packs at the National Renewable Energy Laboratory. A battery thermal management system essential for xEVs for both normal operation during daily driving (achieving life and performance) and off-normal operation during abuse conditions (achieving safety). The battery thermal management system needs to be optimized with the right tools for the lowest cost. Experimental tools such as NREL's isothermal battery calorimeter, thermal imaging, and heat transfer setups are needed. Thermal models and computer-aided engineering tools are useful for robust designs. During abuse conditions, designs should prevent cell-to-cell propagation in a module/pack (i.e., keep the fire small and manageable). NREL's battery ISC device can be used for evaluating the robustness of a module/pack to cell-to-cell propagation.

  3. Bilayer Effects of Antimalarial Compounds.

    Directory of Open Access Journals (Sweden)

    Nicole B Ramsey

    Full Text Available Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05; MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all.

  4. Complex chemistry with complex compounds

    Directory of Open Access Journals (Sweden)

    Eichler Robert

    2016-01-01

    Full Text Available In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the investigation of fragile single molecular species by gas-phase chromatography. The latest success with the heaviest group 6 transactinide seaborgium is highlighted. The formation of a very volatile hexacarbonyl compound Sg(CO6 was observed similarly to its lighter homologues molybdenum and tungsten. The interactions of these gaseous carbonyl complex compounds with quartz surfaces were investigated by thermochromatography. Second-generation experiments are under way to investigate the intramolecular bond between the central metal atom of the complexes and the ligands addressing the influence of relativistic effects in the heaviest compounds. Our contribution comprises some aspects of the ongoing challenging experiments as well as an outlook towards other interesting compounds related to volatile complex compounds in the gas phase.

  5. Assimilation of Unusual Carbon Compounds

    Science.gov (United States)

    Middelhoven, Wouter J.

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

  6. Heat transport imaging in the spin-ladder compound Ca9La5Cu24O41

    NARCIS (Netherlands)

    Otter, M.; Krasnikov, V. V.; Fishman, D. A.; Pshenichnikov, M. S.; Saint-Martin, R.; Revcolevschi, A.; van Loosdrecht, P. H. M.

    All-optical heat transport imaging on the spin-ladder compound Ca9La5Cu24O41 is presented. A 'time-of-flight' principle is discussed along with its experimental veri. cation which can be used to measure the bulk thermal diffusion constant. The results of the thermal imaging experiments clearly

  7. 76 FR 21928 - Washington State University; Facility Operating License No. R-76; Washington State University...

    Science.gov (United States)

    2011-04-19

    ... issued: (1) Allowing for an increase in the possession limits for Uranium-235; and (2) conversion from high-enriched uranium fuel to low-enriched uranium fuel as amendments to the license. The licensee has... standard low-enriched uranium TRIGA (Training, Research, Isotopes, General Atomic) fuel. A detailed...

  8. Crystal growth, FTIR and thermal characterization of bis ...

    Indian Academy of Sciences (India)

    The grown crystals were characterized by elemental analysis, powder X-ray diffraction, thermal analysis, nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infra-red spectroscopy (FTIR) techniques. The chemical composition of the compound was revealed by elemental analysis and its crystallinity was ...

  9. First principles calculations of structural, electronic and thermal ...

    Indian Academy of Sciences (India)

    Administrator

    2013-07-28

    Jul 28, 2013 ... full-potential linear augmented plane wave (FP-LAPW) method are investigated. The exchange–correlation energy ... The electronic band structure shows that the fundamental energy gap is direct (L–L) for all the compounds. Thermal ... voltaic energy converters (Zogg et al 1994). The semi- conductors PbS ...

  10. Thermally-related safety issues associated with thermal batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Guidotti, Ronald Armand

    2006-06-01

    Thermal batteries can experience thermal runaway under certain usage conditions. This can lead to safety issues for personnel and cause damage to associated test equipment if the battery thermally self destructs. This report discusses a number of thermal and design related issues that can lead to catastrophic destruction of thermal batteries under certain conditions. Contributing factors are identified and mitigating actions are presented to minimize or prevent undesirable thermal runaway.

  11. Thermal imaging in medicine

    Directory of Open Access Journals (Sweden)

    Jaka Ogorevc

    2015-12-01

    Full Text Available AbstractIntroduction: Body temperature monitoring is one of the oldest and still one of the most basic diagnostic methods in medicine. In recent years thermal imaging has been increasingly used in measurements of body temperature for diagnostic purposes. Thermal imaging is non-invasive, non-contact method for measuring surface body temperature. Method is quick, painless and patient is not exposed to ionizing radiation or any other body burden.Application of thermal imaging in medicine: Pathological conditions can be indicated as hyper- or hypothermic patterns in many cases. Thermal imaging is presented as a diagnostic method, which can detect such thermal anomalies. This article provides an overview of the thermal imaging applications in various fields of medicine. Thermal imaging has proven to be a suitable method for human febrile temperature screening, for the detection of sites of fractures and infections, a reliable diagnostic tool in the detection of breast cancer and determining the type of skin cancer tumour. It is useful in monitoring the course of a therapy after spinal cord injury, in the detection of food allergies and detecting complications at hemodialysis and is also very effective at the course of treatment of breast reconstruction after mastectomy. With thermal imaging is possible to determine the degrees of burns and early detection of osteomyelitis in diabetic foot phenomenon. The most common and the oldest application of thermal imaging in medicine is the field of rheumatology.Recommendations for use and standards: Essential performance of a thermal imaging camera, measurement method, preparation of a patient and environmental conditions are very important for proper interpretation of measurement results in medical applications of thermal imaging. Standard for screening thermographs was formed for the human febrile temperature screening application.Conclusion: Based on presented examples it is shown that thermal imaging can

  12. Thermal properties of nanofluids.

    Science.gov (United States)

    Philip, John; Shima, P D

    2012-11-15

    Colloidal suspensions of fine nanomaterials in the size range of 1-100 nm in carrier fluids are known as nanofluids. For the last one decade, nanofluids have been a topic of intense research due to their enhanced thermal properties and possible heat transfer applications. Miniaturization and increased operating speeds of gadgets warranted the need for new and innovative cooling concepts for better performance. The low thermal conductivity of conventional heat transfer fluid has been a serious impediment for improving the performance and compactness of engineering equipments. Initial studies on thermal conductivity of suspensions with micrometer-sized particles encountered problems of rapid settling of particles, clogging of flow channels and increased pressure drop in the fluid. These problems are resolved by using dispersions of fine nanometer-sized particles. Despite numerous experimental and theoretical studies, it is still unclear whether the thermal conductivity enhancement in nanofluids is anomalous or within the predictions of effective medium theory. Further, many reports on thermal conductivity of nanofluids are conflicting due to the complex issues associated with the surface chemistry of nanofluids. This review provides an overview of recent advances in the field of nanofluids, especially the important material properties that affect the thermal properties of nanofluids and novel approaches to achieve extremely high thermal conductivities. The background information is also provided for beginners to better understand the subject. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Thermalized axion inflation

    Science.gov (United States)

    Ferreira, Ricardo Z.; Notari, Alessio

    2017-09-01

    We analyze the dynamics of inflationary models with a coupling of the inflaton phi to gauge fields of the form phi F tilde F/f, as in the case of axions. It is known that this leads to an instability, with exponential amplification of gauge fields, controlled by the parameter ξ= dot phi/(2fH), which can strongly affect the generation of cosmological perturbations and even the background. We show that scattering rates involving gauge fields can become larger than the expansion rate H, due to the very large occupation numbers, and create a thermal bath of particles of temperature T during inflation. In the thermal regime, energy is transferred to smaller scales, radically modifying the predictions of this scenario. We thus argue that previous constraints on ξ are alleviated. If the gauge fields have Standard Model interactions, which naturally provides reheating, they thermalize already at ξgtrsim2.9, before perturbativity constraints and also before backreaction takes place. In absence of SM interactions (i.e. for a dark photon), we find that gauge fields and inflaton perturbations thermalize if ξgtrsim3.4 however, observations require ξgtrsim6, which is above the perturbativity and backreaction bounds and so a dedicated study is required. After thermalization, though, the system should evolve non-trivially due to the competition between the instability and the gauge field thermal mass. If the thermal mass and the instabilities equilibrate, we expect an equilibrium temperature of Teq simeq ξ H/bar g where bar g is the effective gauge coupling. Finally, we estimate the spectrum of perturbations if phi is thermal and find that the tensor to scalar ratio is suppressed by H/(2T), if tensors do not thermalize.

  14. Positron annihilation studies on reactor irradiated and thermal annealed ferrocene

    Energy Technology Data Exchange (ETDEWEB)

    Marques Netto, A. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil); Carvalho, R.S. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil); Magalhaes, W.F. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil); Sinisterra, R.D. [Laboratorio de Espectroscopia de Aniquilacao de Positrons-LEAP, Depto. de Quimica, ICEX, Univ. Federal de Minas Gerais-UFMG, Belo Horizonte, MG (Brazil)

    1996-10-01

    Retention and thermal annealing following (n, {gamma}) reaction in solid ferrocene, Fe(C{sub 5}H{sub 5}){sub 2}, were studied by positron annihilation lifetime spectroscopy (PAL). Positronium (Ps) formation was observed in the non-irradiated compound with a probability or intensity (I{sub 3}) of 30%. Upon irradiation of the compound with thermal neutrons in a nuclear reactor, I{sub 3} decreases with increasing irradiation time. Thermal treatment again increases I{sub 3} values from 16% to 25%, revealing an important proportion of molecular reformation without variation of the ortho-positronium lifetime ({tau}{sub 3}). These results point out the major influence of the electronic structure as determining the Ps yields in the pure complex. In the irradiated and non irradiated complexes the results are satisfactorily explained on the basis of the spur model. (orig.)

  15. Lithium-containing scintillators for thermal neutron, fast neutron, and gamma detection

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.

    2016-03-01

    In one embodiment, a scintillator includes a scintillator material; a primary fluor, and a Li-containing compound, where the Li-containing compound is soluble in the primary fluor, and where the scintillator exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays.

  16. Biomedical Compounds from Marine organisms

    OpenAIRE

    Jha, Rajeev Kumar; Zi-rong, Xu

    2004-01-01

    The Ocean, which is called the ‘mother of origin of life’, is also the source of structurally unique natural products that are mainly accumulated in living organisms. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immuno-deficiency syndrome (AIDS), arthritis, etc., while other compounds have been developed as analgesics or to treat inflammation, etc...

  17. Advanced thermal management materials

    CERN Document Server

    Jiang, Guosheng; Kuang, Ken

    2012-01-01

    ""Advanced Thermal Management Materials"" provides a comprehensive and hands-on treatise on the importance of thermal packaging in high performance systems. These systems, ranging from active electronically-scanned radar arrays to web servers, require components that can dissipate heat efficiently. This requires materials capable of dissipating heat and maintaining compatibility with the packaging and dye. Its coverage includes all aspects of thermal management materials, both traditional and non-traditional, with an emphasis on metal based materials. An in-depth discussion of properties and m

  18. Alternatives to eigenstate thermalization.

    Science.gov (United States)

    Rigol, Marcos; Srednicki, Mark

    2012-03-16

    An isolated quantum many-body system in an initial pure state will come to thermal equilibrium if it satisfies the eigenstate thermalization hypothesis (ETH). We consider alternatives to ETH that have been proposed. We first show that von Neumann's quantum ergodic theorem relies on an assumption that is essentially equivalent to ETH. We also investigate whether, following a sudden quench, special classes of pure states can lead to thermal behavior in systems that do not obey ETH, namely, integrable systems. We find examples of this, but only for initial states that obeyed ETH before the quench.

  19. Thermal energy transformer

    Science.gov (United States)

    Berdahl, C. M.; Thiele, C. L. (Inventor)

    1979-01-01

    For use in combination with a heat engine, a thermal energy transformer is presented. It is comprised of a flux receiver having a first wall defining therein a radiation absorption cavity for converting solar flux to thermal energy, and a second wall defining an energy transfer wall for the heat engine. There is a heat pipe chamber interposed between the first and second walls having a working fluid disposed within the chamber and a wick lining the chamber for conducting the working fluid from the second wall to the first wall. Thermal energy is transferred from the radiation absorption cavity to the heat engine.

  20. The elastic properties of Mn3(Cu1−xGexN compounds

    Directory of Open Access Journals (Sweden)

    B. Y. Qu

    2011-12-01

    Full Text Available We present an ab initio study of the elastic properties of the negative thermal expansion (NTE compound Mn3(Cu1−xGexN. The calculated energies show that the Ge atoms can be easily doped into the compound and, the distribution of the Ge atoms in the compound is very uniform. The elastic moduli of the compound in the form of polycrystalline are evaluated according to the Voigt-Reuss-Hill approximation, which show that the doped Ge enhances the ductile character of the compound, with fairly high elastic anisotropy. Furthermore, it is found that the bulk modulus and the Young's modulus of the compound increase as the Ge content increases from 12.5 % to 50 %, being in agreement with experiments. Through analyzing the electronic structures, we propose that these elastic features are essentially stemmed from the valence states and the valence electrons of the doped Ge.

  1. Thermal analysis of cement pastes with superabsorbent polymers

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Jensen, Ole Mejlhede; Lukosiute, Irena

    2013-01-01

    Thermal analysis of cement systems is very helpful in the understanding of many different properties of cementitious compounds, both for the original reacting compounds, and also for the resulting hydration products. Superabsorbent polymers can be added to cement systems with many different reasons......, so it is relevant that fundamental knowledge of this new compound on the development of hydration is well understood [1-3]. This paper reports research on thermal analysis of cement pastes with superabsorbent polymers. We have studied several parameters: the concentration of SAP in the system......, the effect of particle size distribution, and their influence on the hydration process with focus on cement-silica systems. This is done at different thermodynamic conditions, so the energy of activation in the different systems can be accessed. This paper provides information relevant to hydration modelling...

  2. Study of thermal behavior of phytic acid

    Directory of Open Access Journals (Sweden)

    André Luis Máximo Daneluti

    2013-06-01

    Full Text Available Phytic acid is a natural compound widely used as depigmenting agent in galenic cosmetic emulsions. However, we have observed experimentally that phytic acid, when heated to 150 ºC for around one hour, shows evidence of thermal decomposition. Few studies investigating this substance alone with regard to its stability are available in the literature. This fact prompted the present study to characterize this species and its thermal behavior using thermal analysis (TG/DTG and DSC and to associate the results of these techniques with those obtained by elemental analysis (EA and absorption spectroscopy in the infrared region. The TG/DTG and DSC curves allowed evaluation of the thermal behavior of the sample of phytic acid and enabled use of the non-isothermal thermogravimetric method to study the kinetics of the three main mass-loss events: dehydration I, dehydration II and thermal decomposition. The combination of infrared absorption spectroscopy and elemental analysis techniques allowed evaluation of the intermediate products of the thermal decomposition of phytic acid. The infrared spectra of samples taken during the heating process revealed a reduction in the intensity of the absorption band related to O-H stretching as a result of the dehydration process. Furthermore, elemental analysis results showed an increase in the carbon content and a decrease in the hydrogen content at temperatures of 95, 150, 263 and 380 °C. Visually, darkening of the material was observed at 150 °C, indicating that the thermal decomposition of the material started at this temperature. At a temperature of 380 °C, thermal decomposition progressed, leading to a decrease in carbon and hydrogen. The results of thermogravimetry coupled with those of elemental analysis allow us to conclude that there was agreement between the percentages of phytic acid found in aqueous solution. The kinetic study by the non-isothermal thermogravimetric method showed that the dehydration

  3. Improved Thermal Modulator for Gas Chromatography

    Science.gov (United States)

    Hasselbrink, Ernest Frederick, Jr.; Hunt, Patrick J.; Sacks, Richard D.

    2008-01-01

    An improved thermal modulator has been invented for use in a variant of gas chromatography (GC). The variant in question denoted as two-dimensional gas chromatography (2DGC) or GC-GC involves the use of three series-connected chromatographic columns, in the form of capillary tubes coated interiorly with suitable stationary phases (compounds for which different analytes exhibit different degrees of affinity). The two end columns are relatively long and are used as standard GC columns. The thermal modulator includes the middle column, which is relatively short and is not used as a standard GC column: instead, its temperature is modulated to affect timed adsorption and desorption of analyte gases between the two end columns in accordance with a 2DGC protocol.

  4. Crystallographic properties of fertilizer compounds

    Energy Technology Data Exchange (ETDEWEB)

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  5. Phenolic Compounds in Brassica Vegetables

    Directory of Open Access Journals (Sweden)

    Pablo Velasco

    2010-12-01

    Full Text Available Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

  6. Fourth symposium on macrocyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, J. J.; Izatt, R. M.

    1980-01-01

    Both theoretical and experimental aspects of the properties and behavior of synthetic and naturally occurring macrocyclic compounds are covered in this symposium. This document contains abstracts of the papers. (DLC)

  7. Thermal cloak-concentrator

    Science.gov (United States)

    Shen, Xiangying; Li, Ying; Jiang, Chaoran; Ni, Yushan; Huang, Jiping

    2016-07-01

    For macroscopically manipulating heat flow at will, thermal metamaterials have opened a practical way, which possesses a single function, such as either cloaking or concentrating the flow of heat even though environmental temperature varies. By developing a theory of transformation heat transfer for multiple functions, here we introduce the concept of intelligent thermal metamaterials with a dual function, which is in contrast to the existing thermal metamaterials with single functions. By assembling homogeneous isotropic materials and shape-memory alloys, we experimentally fabricate a kind of intelligent thermal metamaterials, which can automatically change from a cloak (or concentrator) to a concentrator (or cloak) when the environmental temperature changes. This work paves an efficient way for a controllable gradient of heat, and also provides guidance both for arbitrarily manipulating the flow of heat and for efficiently designing similar intelligent metamaterials in other fields.

  8. Paradoxes of thermal radiation

    Energy Technology Data Exchange (ETDEWEB)

    Besson, U [Department of Physics ' A Volta' , University of Pavia, Via A Bassi 6, 27100 Pavia (Italy)], E-mail: ugo.besson@unipv.it

    2009-09-15

    This paper presents an analysis of the thermal behaviour of objects exposed to a solar-type flux of thermal radiation. It aims to clarify certain apparent inconsistencies between theory and observation, and to give a detailed exposition of some critical points that physics textbooks usually treat in an insufficient or incorrect way. In particular, the paper examines the equilibrium temperature reached by objects exposed to solar thermal radiation and the temperature difference between their illuminated and shaded sides. These problems are studied first by analysing the simple ideal case of an isolated object, subsequently by taking into account the thermal radiation emitted by the environment, and finally by considering also the heat exchange with the surrounding air. Some examples are developed and numerical data are provided. The topic is developed in a way that can be suitable for both undergraduate student and general physicist.

  9. Compliant thermal microactuators

    DEFF Research Database (Denmark)

    Jonsmann, Jacques; Sigmund, Ole; Bouwstra, Siebe

    1999-01-01

    Two dimensional compliant metallic thermal microactuators are designed using topology optimisation, and microfabricated using rapid prototyping techniques. Structures are characterised using advanced image analysis, yielding a very high precision. Characterised structures behave in a way which can...

  10. Compliant thermal microactuators

    DEFF Research Database (Denmark)

    Jonsmann, Jacques; Sigmund, Ole; Bouwstra, Siebe

    1999-01-01

    Two dimensional compliant metallic thermal microactuators are designed using topology optimisation, and microfabricated using rapid prototyping techniques. Structures are characterised using advanced image analysis, yielding a very high precision. Characterised structures behave in accordance...

  11. Thermal Properties Measurement Report

    Energy Technology Data Exchange (ETDEWEB)

    Carmack, Jon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Braase, Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Papesch, Cynthia [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hurley, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tonks, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gofryk, Krzysztof [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fielding, Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Knight, Collin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Meyer, Mitch [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    The Thermal Properties Measurement Report summarizes the research, development, installation, and initial use of significant experimental thermal property characterization capabilities at the INL in FY 2015. These new capabilities were used to characterize a U3Si2 (candidate Accident Tolerant) fuel sample fabricated at the INL. The ability to perform measurements at various length scales is important and provides additional data that is not currently in the literature. However, the real value of the data will be in accomplishing a phenomenological understanding of the thermal conductivity in fuels and the ties to predictive modeling. Thus, the MARMOT advanced modeling and simulation capability was utilized to illustrate how the microstructural data can be modeled and compared with bulk characterization data. A scientific method was established for thermal property measurement capability on irradiated nuclear fuel samples, which will be installed in the Irradiated Material Characterization Laboratory (IMCL).

  12. Graphene thermal flux transistor.

    Science.gov (United States)

    Shafranjuk, S E

    2016-11-24

    Insufficient flexibility of existing approaches to controlling the thermal transport in atomic monolayers limits their capability for use in many applications. Here, we examine the means of electrode doping to control the thermal flux Q due to phonons propagating along the atomic monolayer. We found that the frequency of the electron-restricted phonon scattering strongly depends on the concentration nC. of the electric charge carriers, established by the electric potentials applied to local gates. As a result of the electrode doping, nC is increased, causing a sharp rise in both the electrical conductivity and Seebeck coefficient, while the thermal conductivity tumbles. Therefore, the effect of the thermal transistor improves the figure of merit of nanoelectronic circuits.

  13. Thermal springs of Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Breckenridge, R.M.; Hinckley, B.S.

    1978-01-01

    This bulletin attempts, first, to provide a comprehensive inventory of the thermal springs of Wyoming; second, to explore the geologic and hydrologic factors producing these springs; and, third, to analyze the springs collectively as an indicator of the geothermal resources of the state. A general discussion of the state's geology and the mechanisms of thermal spring production, along with a brief comparison of Wyoming's springs with worldwide thermal features are included. A discussion of geothermal energy resources, a guide for visitors, and an analysis of the flora of Wyoming's springs follow the spring inventory. The listing and analysis of Wyoming's thermal springs are arranged alphabetically by county. Tabulated data are given on elevation, ownership, access, water temperature, and flow rate. Each spring system is described and its history, general characteristics and uses, geology, hydrology, and chemistry are discussed. (MHR)

  14. Thermal Acoustic Fatigue Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — The Thermal Acoustic Fatigue Apparatus (TAFA) is a progressive wave tube test facility that is used to test structures for dynamic response and sonic fatigue due to...

  15. Thermal hyperbolic metamaterials.

    Science.gov (United States)

    Guo, Yu; Jacob, Zubin

    2013-06-17

    We explore the near-field radiative thermal energy transfer properties of hyperbolic metamaterials. The presence of unique electromagnetic states in a broad bandwidth leads to super-planckian thermal energy transfer between metamaterials separated by a nano-gap. We consider practical phonon-polaritonic metamaterials for thermal engineering in the mid-infrared range and show that the effect exists in spite of the losses, absorption and finite unit cell size. For thermophotovoltaic energy conversion applications requiring energy transfer in the near-infrared range we introduce high temperature hyperbolic metamaterials based on plasmonic materials with a high melting point. Our work paves the way for practical high temperature radiative thermal energy transfer applications of hyperbolic metamaterials.

  16. Antitumor compounds from marine actinomycetes.

    OpenAIRE

    Salas, José A.; Carmen Méndez; Carlos Olano

    2009-01-01

    Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal pept...

  17. Cancer chemoprevention by natural compounds

    OpenAIRE

    スズキ, マスミ; Masumi, SUZUI

    2007-01-01

    There is growing interest in the use of natural compounds for the treatment and prevention of a wide variety of diseases, including cancer. Several herb-derived components are currently evaluated in preclinical studies as potential cancer chemopreventive agents. We have recently found that several herbal plants in the Ryukyu Islands, or any other natural compound, have a potential chemopreventive effect on biomarkers of colon carcinogenesis and a growth inhibitory effect on human cancer cells...

  18. Phenolic Compounds in Brassica Vegetables

    OpenAIRE

    Cartea González, María Elena; Francisco Candeira, Marta; Soengas Fernández, María del Pilar; Velasco Pazos, Pablo

    2011-01-01

    Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The...

  19. Anaerobic Degradation of Phenolic Compounds

    OpenAIRE

    Schink, Bernhard; Philipp, Bodo; Jochen A Müller

    2000-01-01

    Mononuclear aromatic compounds are degraded anaerobically through three main pathways, the benzoyl-CoA pathway, the resorcinol pathway, and the phloroglucinol pathway. Various modification reactions channel a broad variety of mononuclear aromatics including aromatic hydrocarbons into either one of these three pathways. Recently, a further pathway was discovered with hydroxyhydroquinone as central intermediate through which especially nitrate-reducing bacteria degrade phenolic compounds and so...

  20. Effect of drying on the bioactive compounds, antioxidant, antibacterial and antityrosinase activities of pomegranate peel

    OpenAIRE

    Mphahlele, Rebogile R.; Fawole, Olaniyi A; Makunga, Nokwanda P.; Opara, Umezuruike L.

    2016-01-01

    Background The use of pomegranate peel is highly associated with its rich phenolic concentration. Series of drying methods are recommended since bioactive compounds are highly sensitive to thermal degradation. The study was conducted to evaluate the effects of drying on the bioactive compounds, antioxidant as well as antibacterial and antityrosinase activities of pomegranate peel. Methods Dried pomegranate peels with the initial moisture content of 70.30?% wet basis were prepared by freeze an...

  1. Antioxidant and antibacterial effects of natural phenolic compounds on green composite materials

    OpenAIRE

    ESPAÑA GINER, JOSÉ MANUEL; Fages, E.; Moriana Torró, Rosana; Boronat Vitoria, Teodomiro; Balart Gimeno, Rafael Antonio

    2012-01-01

    The aim of this study is to establish the thermal performance of a biocomposite (Arbofill kokos (R)), stabilized with different natural phenolic additives, to check the antioxidant capacity of the resulting compounds. Different phenolic compounds (thymol, carvacrol, a-tocopherol, and tannic acid) were used as biobased additives and the concentrations ranged between 0.5 wt% and 2 wt%. The results obtained were compared with formulations containing a typical industrial petroleum-based antioxida...

  2. ThermalTracker Software

    Energy Technology Data Exchange (ETDEWEB)

    2016-08-10

    The software processes recorded thermal video and detects the flight tracks of birds and bats that passed through the camera's field of view. The output is a set of images that show complete flight tracks for any detections, with the direction of travel indicated and the thermal image of the animal delineated. A report of the descriptive features of each detected track is also output in the form of a comma-separated value text file.

  3. Thermal Anemometry Grid Sensor

    OpenAIRE

    Martin Arlit; Eckhard Schleicher; Uwe Hampel

    2017-01-01

    A novel thermal anemometry grid sensor was developed for the simultaneous measurement of cross-sectional temperature and axial velocity distribution in a fluid flow. The sensor consists of a set of platinum resistors arranged in a regular grid. Each platinum resistor allows the simultaneous measurement of fluid temperature via electrical resistance and flow velocity via constant voltage thermal anemometry. Cross-sectional measurement was enabled by applying a special multiplexing-excitation s...

  4. Thermal conveyance systems

    Energy Technology Data Exchange (ETDEWEB)

    Meador, J.T.

    1978-09-01

    The purpose of the evaluation is to characterize modern technology for long-distance, large-diameter, underground steam and high-temperature water (HTW) transport systems and for hot-water and chilled-water systems that distribute thermal energy within communities. Data on the status of existing systems have been compiled and compared with recommended design factors for fluid flow to aid in parameter selection for assessing performance in transporting and distributing thermal energy.

  5. Thermal properties examples

    OpenAIRE

    Bantle, Michael

    2017-01-01

    Thermal properties of selected organic products were investigated using novel DSC technique and methods of determination. The report includes determination of freezing temperatures, glass transition temperatures, amount of ice, and end of freezing point, heat capacity and thermal conductivity for selected cases. One part of the experimental work was devoted to investigate the difference between oils extracted from organic and conventional salmon. The main aim of the investigation was to u...

  6. Thermal radiation heat transfer

    CERN Document Server

    Howell, John R; Siegel, Robert

    2016-01-01

    Further expanding on the changes made to the fifth edition, Thermal Radiation Heat Transfer, 6th Edition continues to highlight the relevance of thermal radiative transfer and focus on concepts that develop the radiative transfer equation (RTE). The book explains the fundamentals of radiative transfer, introduces the energy and radiative transfer equations, covers a variety of approaches used to gauge radiative heat exchange between different surfaces and structures, and provides solution techniques for solving the RTE.

  7. Compound Odontoma in young girl

    Directory of Open Access Journals (Sweden)

    Nurwahida Nurwahida

    2017-08-01

    Full Text Available Introduction. Odontomas are the most common type of odontogenic tumors and generally they are asymptomatic. These tumors are formed from enamel and dentin, and can have variable amounts of cement and pulp tissues. According to radiographic, microscopic, and clinical features, two types of odontomas are recognized: Complex and compound odontomas. Complex odontomas occur mostly in the posterior part of the mandible and compound odontomas in the anterior maxilla. Case Report. A young girl patient, 9 years old came to Department of Oral and Maxillofacial Surgery with a slow growing and asymptomatic swelling in her left posterior mandible for 5 years in his history taking. The panoramic radiograph show  a radioopacity and radiolucent lesion at the lower second molar region, with well-corticated limits. An insisional biopsi   confirmed  as compound odontoma. The surgery  performed with simple enucleation and curettage under general anaesthesia. Discussion. Compound odontomas are usually located in the anterior maxilla, over the crowns of unerupted teeth, or between the roots of erupted teeth. In this case report, Compound odontomas are found in the posterior mandible. Conclusion. Compound odontomas in the posterior mandible is a rare. The treatment of odontomas depends on the size of the lesion. The early diagnosis, the treatment of choice is conservative surgical enucleation and curettage and prognosis is excellent.

  8. Battery Thermal Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Keyser, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-08

    The operating temperature is critical in achieving the right balance between performance, cost, and life for both Li-ion batteries and ultracapacitors. The chemistries of advanced energy-storage devices - such as lithium-based batteries - are very sensitive to operating temperature. High temperatures degrade batteries faster while low temperatures decrease their power and capacity, affecting vehicle range, performance, and cost. Understanding heat generation in battery systems - from the individual cells within a module, to the inter-connects between the cells, and across the entire battery system - is imperative for designing effective thermal-management systems and battery packs. At NREL, we have developed unique capabilities to measure the thermal properties of cells and evaluate thermal performance of battery packs (air or liquid cooled). We also use our electro-thermal finite element models to analyze the thermal performance of battery systems in order to aid battery developers with improved thermal designs. NREL's tools are used to meet the weight, life, cost, and volume goals set by the U.S. Department of Energy for electric drive vehicles.

  9. Local Thermal Insulating Materials For Thermal Energy Storage ...

    African Journals Online (AJOL)

    Thermal insulation is one of the most important components of a thermal energy storage system. In this paper the thermal properties of selected potential local materials which can be used for high temperature insulation are presented. Thermal properties of seven different samples were measured. Samples consisted of: ...

  10. Effects of water and sawdust additives on thermal effusivity, thermal ...

    African Journals Online (AJOL)

    The effects of water and sawdust additives on the thermal effusivity (e), thermal conductivity (λ), and durability of cement-stabilized laterites were investigated. The thermal effusivity (e) and conductivity(λ) have direct influ-ence on heat transfer and thermal insulation in buildings, and the parameters were determined by hot ...

  11. Tunable Radiative Thermal Rectifiers : Toward Thermal Logical Circuits

    OpenAIRE

    Nefzaoui, Elyes; Ezzahri, Younès; Joulain, Karl; Drevillon, Jérémie

    2015-01-01

    International audience; Thermal rectification can be defined as an asymmetry in the heat flux when the temperature difference between two interacting thermal reservoirs is reversed. We present a thermal rectifier concept based on far-field radiative heat transfer. The device is composed of two opaque thermal baths 1 and 2 at temperatures T 1 and T 2 respectively and exchanging heat through thermal radiation. The two interacting bodies are made of spectrally selective photonic structures with ...

  12. Origin of the Giant Negative Thermal Expansion in Mn3(Cu0.5Ge0.5N

    Directory of Open Access Journals (Sweden)

    B. Y. Qu

    2012-01-01

    Full Text Available The giant negative thermal expansion in the Ge-doped antiperovskite Mn3CuN compound is theoretically studied by using the first principles calculations. We propose that such a negative thermal expansion property is essentially attributed to the magnetic phase transition, rather than to the lattice vibration of the Ge-doped compound. Furthermore, we found that the doped Ge atoms in the compound significantly enhance the antiferromagnetic couplings between the nearest neighboring Mn ions, which effectively stabilizes the magnetic ground states. In addition, the nature of the temperature-dependent changes in the volume of the Ge-doped compound was revealed.

  13. Thermal and spectroscopic studies on solid ibuprofen complexes of lighter trivalent lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Gálico, D.A.; Holanda, B.B.C.; Guerra, R.B.; Legendre, A.O.; Rinaldo, D. [UNESP – Univ Estadual Paulista, Faculdade de Ciências, Departamento de Química, São Paulo CEP 17033-260 (Brazil); Treu-Filho, O. [UNESP – Univ Estadual Paulista, Instituto de Química, São Paulo CEP 14800-900 (Brazil); Bannach, G., E-mail: gilbert@fc.unesp.br [UNESP – Univ Estadual Paulista, Faculdade de Ciências, Departamento de Química, São Paulo CEP 17033-260 (Brazil)

    2014-01-10

    Highlights: • Lighter trivalent lanthanide complexes of ibuprofen have been synthesized. • The TG-FTIR allowed the identification of propane as the gas evolved during the thermal decomposition of the neodymium compound. • The thermal analysis provided information about the composition, dehydration, thermal behavior and thermal decomposition of the samples. • The theoretical and experimental spectroscopic studies suggest that the carboxylate group of ibuprofen is coordinated to the metals by a bidentate bond. - Abstract: Solid-state compounds of general formula Ln(L){sub 3}, in which L is ibuprofen and Ln stands for trivalent La, Ce, Pr, Nd, Sm and Eu, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry (DRX), complexometry, Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetry coupled to Fourier-transformed infrared spectroscopy (TG-FTIR) were used to characterize these compounds. The results provided information concerning the chemical composition, dehydration, coordination modes of the ligands, crystallinity of the samples, thermal behavior and thermal decomposition of the compounds. The theoretical and experimental spectroscopic studies suggest that ibuprofen coordinates through the carboxylate group as a chelating ligand.

  14. Landsat and Thermal Infrared Imaging

    Science.gov (United States)

    Arvidson, Terry; Barsi, Julia; Jhabvala, Murzy; Reuter, Dennis

    2012-01-01

    The purpose of this chapter is to describe the collection of thermal images by Landsat sensors already on orbit and to introduce the new thermal sensor to be launched in 2013. The chapter describes the thematic mapper (TM) and enhanced thematic mapper plus (ETM+) sensors, the calibration of their thermal bands, and the design and prelaunch calibration of the new thermal infrared sensor (TIRS).

  15. Compounded bioidentical menopausal hormone therapy.

    Science.gov (United States)

    2012-08-01

    Although improvement in long-term health is no longer an indication for menopausal hormone therapy, evidence supporting fewer adverse events in younger women, combined with its high overall effectiveness, has reinforced its usefulness for short-term treatment of menopausal symptoms. Menopausal therapy has been provided not only by commercially available products but also by compounding, or creation of an individualized preparation in response to a health care provider's prescription to create a medication tailored to the specialized needs of an individual patient. The Women's Health Initiative findings, coupled with an increase in the direct-to-consumer marketing and media promotion of compounded bioidentical hormonal preparations as safe and effective alternatives to conventional menopausal hormone therapy, have led to a recent increase in the popularity of compounded bioidentical hormones as well as an increase in questions about the use of these preparations. Not only is evidence lacking to support superiority claims of compounded bioidentical hormones over conventional menopausal hormone therapy, but these claims also pose the additional risks of variable purity and potency and lack efficacy and safety data. The Committee on Gynecologic Practice of the American College of Obstetricians and Gynecologists and the Practice Committee of the American Society for Reproductive Medicine provide an overview of the major issues of concern surrounding compounded bioidentical menopausal hormone therapy and provide recommendations for patient counseling. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  16. Vanadium Compounds as PTP Inhibitors

    Directory of Open Access Journals (Sweden)

    Elsa Irving

    2017-12-01

    Full Text Available Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs and protein tyrosine phosphatases (PTPs. Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

  17. The demise of compound houses

    DEFF Research Database (Denmark)

    Andreasen, Jørgen; Eskemose Andersen, Jørgen

    2006-01-01

    The compound house has long provided the accomodation required by low income households in West African cities. In Kumasi, Ghana, evidence suggests that no new compounds are being built. Instead, the city is being ringed by relatively affluent villa-style development while neighbourhoods dominate...... perceptions of what is acceptable urban life to the growing cohort of young African households. In addition, there is a need to explore innovative forms of tenure in order to secure the majority of Kumasi's population access to land for housing.......The compound house has long provided the accomodation required by low income households in West African cities. In Kumasi, Ghana, evidence suggests that no new compounds are being built. Instead, the city is being ringed by relatively affluent villa-style development while neighbourhoods dominated...... by compounds are increasing in density and experiencing considerable extension activity. Within the system of customary tenure through the chieftaincy, the availability and access to land for the lower income segment of the urban population is now extremely limited. The research examines the characteristics...

  18. Extraterrestrial Organic Compounds in Meteorites

    Science.gov (United States)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  19. Promiscuity progression of bioactive compounds over time

    OpenAIRE

    Hu, Ye; Jasial, Swarit; Bajorath, J?rgen

    2015-01-01

    In the context of polypharmacology, compound promiscuity is rationalized as the ability of small molecules to specifically interact with multiple targets. To study promiscuity progression of bioactive compounds in detail, nearly 1 million compounds and more than 5.2 million activity records were analyzed. Compound sets were assembled by applying different data confidence criteria and selecting compounds with activity histories over many years. On the basis of release dates, compounds and acti...

  20. ASSESSING LONGITUDINAL THERMAL CONNECTIVITY ...

    Science.gov (United States)

    Water temperature is a key driver of ecological processes in aquatic environments and can influence biological connectivity among riverine habitats. Riverine fish and other mobile aquatic species often must navigate a variety of physical barriers such as dams and culverts. For Pacific salmon, warm water can also pose barriers to migration, but the presence of patches of cooler water within rivers can serve as important refuges and potentially as stepping stones at times of day when temperatures are elsewhere unsuitable along the migratory corridor. Rising water temperature associated with climate change has become a major conservation concern for freshwater species and poses challenges for natural resource managers who must consider multiple factors in addition to uncertainty in climate predictions. Thermal refuges can contribute to watershed-scale thermal resilience and are increasingly considered in water quality regulations; however, monitoring such refuges and effectively operationalizing the concept for management has proved difficult. We review what is known about use of thermal refuges by coldwater fishes in natural systems, and then we present two case study applications in which we characterize thermal patterns in rivers (e.g., the frequency, size, spacing, and location of thermal patches) and consider effects on salmon in a management context. In our first example, we illustrate methods for quantifying spatial heterogeneity in stream temperatures at bi

  1. Thermal degradation of injectable epinephrine.

    Science.gov (United States)

    Church, W H; Hu, S S; Henry, A J

    1994-05-01

    The degradation of epinephrine in USP injectable cartridges was investigated under different heating conditions. Epinephrine (EPI) and EPI sulfonic acid (EPI-SA) levels in 1:10,000 (0.1 mg/mL) EPI injectable solutions subjected to either cyclical (65 degrees C for 8 hr/d for 4 to 12 weeks) or constant (65 degrees C for 7 days) heating were determined using high-pressure liquid chromatography with diode array and electrochemical detection. Constant (169 total hours of heat exposure) heating resulted in complete degradation of both compounds and dark brown discoloration of the solution. Cyclical heating (672 total hours of heat exposure) resulted in a 31% reduction in EPI concentration and a 225% increase in EPI-SA concentration with no discoloration of the solution. In laboratory-prepared solutions, the degradation of EPI and the formation of EPI-SA was found to be dependent on sodium metabisulfite concentration and the duration of cyclical heating. These results indicate that the thermal stability of EPI and the formation of EPI-SA depends on the method of heat exposure and the amount of bisulfite present in the solution.

  2. Antitumor compounds from marine actinomycetes.

    Science.gov (United States)

    Olano, Carlos; Méndez, Carmen; Salas, José A

    2009-06-11

    Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds.

  3. Antitumor Compounds from Marine Actinomycetes

    Directory of Open Access Journals (Sweden)

    José A. Salas

    2009-06-01

    Full Text Available Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds.

  4. Gallium-containing anticancer compounds.

    Science.gov (United States)

    Chitambar, Christopher R

    2012-06-01

    There is an ever pressing need to develop new drugs for the treatment of cancer. Gallium nitrate, a group IIIa metal salt, inhibits the proliferation of tumor cells in vitro and in vivo and has shown activity against non-Hodgkin's lymphoma and bladder cancer in clinical trials. Gallium can function as an iron mimetic and perturb iron-dependent proliferation and other iron-related processes in tumor cells. Gallium nitrate lacks crossresistance with conventional chemotherapeutic drugs and is not myelosuppressive; it can be used when other drugs have failed or when the blood count is low. Given the therapeutic potential of gallium, newer generations of gallium compounds are now in various phases of preclinical and clinical development. These compounds hold the promise of greater anti-tumor activity against a broader spectrum of cancers. The development of gallium compounds for cancer treatment and their mechanisms of action will be discussed.

  5. Concepts in Thermal Physics

    CERN Document Server

    Blundell, Stephen J

    2006-01-01

    This modern introduction to thermal physics contains a step-by-step presentation of the key concepts. The text is copiously illustrated and each chapter contains several worked examples. - ;An understanding of thermal physics is crucial to much of modern physics, chemistry and engineering. This book provides a modern introduction to the main principles that are foundational to thermal physics, thermodynamics, and statistical mechanics. The key concepts are carefully presented in a clear way, and new ideas are illustrated with copious worked examples as well as a description of the historical background to their discovery. Applications are presented to subjects as. diverse as stellar astrophysics, information and communication theory, condensed matter physics, and climate change. Each chapter concludes with detailed exercises. -

  6. Highly Thermal Conductive Nanocomposites

    Science.gov (United States)

    Sun, Ya-Ping (Inventor); Connell, John W. (Inventor); Veca, Lucia Monica (Inventor)

    2017-01-01

    Disclosed are methods for forming carbon-based fillers as may be utilized in forming highly thermal conductive nanocomposite materials. Formation methods include treatment of an expanded graphite with an alcohol/water mixture followed by further exfoliation of the graphite to form extremely thin carbon nanosheets that are on the order of between about 2 and about 10 nanometers in thickness. Disclosed carbon nanosheets can be functionalized and/or can be incorporated in nanocomposites with extremely high thermal conductivities. Disclosed methods and materials can prove highly valuable in many technological applications including, for instance, in formation of heat management materials for protective clothing and as may be useful in space exploration or in others that require efficient yet light-weight and flexible thermal management solutions.

  7. Electrical and Thermal Conductivity

    Science.gov (United States)

    Ventura, Guglielmo; Perfetti, Mauro

    After a Sect. 1.1 devoted to electrical conductivity and a section that deals with magnetic and dielectric losses ( 1.2 ), this chapter explores the theory of thermal conduction in solids. The examined categories of solids are: metals Sect. 1.3.2 , Dielectrics Sects. 1.3.3 and 1.3.4 and Nanocomposites Sect. 1.3.5 . In Sect. 1.3.6 the problem of thermal and electrical contact between materials is considered because contact resistance occurring at conductor joints in magnets or other high power applications can lead to undesirable electrical losses. At low temperature, thermal contact is also critical in the mounting of temperature sensors, where bad contacts can lead to erroneous results, in particular when superconductivity phenomena are involved.

  8. Thermal Responsive Envelope

    DEFF Research Database (Denmark)

    Foged, Isak Worre; Pasold, Anke

    2015-01-01

    alterations, their respective durability and copper’s architectural (visual and transformative) aesthetic qualities. Through the use of an evolutionary solver, the composite structure of the elements are organised to find the bending behaviour specified by and for the thermal environments. The entire model......The paper presents an architectural computational method and model, which, through additive and subtractive processes, create composite elements with bending behaviour based on thermal variations in the surrounding climatic environment. The present effort is focused on the manipulation of assembly...... composite layers and their relative layer lengths thereby embedding the merged material effect to create a responsive behavioural architectural envelope. Copper and polypropylene are used as base materials for the composite structure due to their high differences in thermal expansion, surface emissivity...

  9. Design without thermal bridges

    Directory of Open Access Journals (Sweden)

    Maltseva Irina

    2018-01-01

    Full Text Available The main focus of the article is on the quality design and implementation of the thermal insulation of buildings. Shells of buildings consist not only of conventional structures (wall, roof, ceiling, but also of edges, corners, joints and places of disruption of the outer thermal insulation shell integrity (due to through passage of pipelines, ventilation ducts and etc.. In all these places, heat losses are generally increased in comparison with conventional surfaces. Some of them are easily taken into account by calculation, using a special method proposed by the authors. Other thermal bridges due to unfavorable structural details can be avoided by observing the rules and recommendations that are classified and discussed in detail in this article.

  10. The structures of binary compounds

    CERN Document Server

    Hafner, J; Jensen, WB; Majewski, JA; Mathis, K; Villars, P; Vogl, P; de Boer, FR

    1990-01-01

    - Up-to-date compilation of the experimental data on the structures of binary compounds by Villars and colleagues. - Coloured structure maps which order the compounds into their respective structural domains and present for the first time the local co-ordination polyhedra for the 150 most frequently occurring structure types, pedagogically very helpful and useful in the search for new materials with a required crystal structure. - Crystal co-ordination formulas: a flexible notation for the interpretation of solid-state structures by chemist Bill Jensen. - Recent important advances in unders

  11. Cytotoxic Compounds from Aloe megalacantha

    Directory of Open Access Journals (Sweden)

    Negera Abdissa

    2017-07-01

    Full Text Available Phytochemical investigation of the ethyl acetate extract of the roots of Aloe megalacantha led to the isolation of four new natural products—1,8-dimethoxynepodinol (1, aloesaponarin III (2, 10-O-methylchrysalodin (3 and methyl-26-O-feruloyl-oxyhexacosanate (4—along with ten known compounds. All purified metabolites were characterized by NMR, mass spectrometric analyses and comparison with literature data. The isolates were evaluated for their cytotoxic activity against a human cervix carcinoma cell line KB-3-1 and some of them exhibited good activity, with aloesaponarin II (IC50 = 0.98 µM being the most active compound.

  12. Antimicrobial compounds of porcine mucosa

    Science.gov (United States)

    Kotenkova, E. A.; Lukinova, E. A.; Fedulova, L. V.

    2017-09-01

    The aim of the study was to investigate porcine oral cavity mucosa (OCM), nasal cavity mucosa (NCM), rectal mucosa (RM) and tongue mucosa (TM) as sources of antimicrobial compounds. Ultrafiltrates with MW >30 kDa, MW 5-30 kDa and MW antimicrobial activity against Escherichia coli and Proteus vulgaris. NCM ultrafiltrates revealed the highest antibacterial activity in respect to negative control: for the fraction with MW >30 kDa, the zone of microbial growth inhibition was 7.5 mm, for the MWantimicrobial compounds, which could be an actual alternative for reduction of microbial spoilage of foods.

  13. A Study on Actual Conditions of Thermal Environment and Indoor Air Quality in a Japanese Traditional House Corresponding to Sericulture

    National Research Council Canada - National Science Library

    Wang, Yan; Yoshino, Yasuko; Kumagai, Kazukiyo; Takahashi, Miyuki

    2010-01-01

    .... Therefore we describe the actual conditions of the thermal environment such as temperature and humidity when the silkworm is breeding, and the air quality such as CO2, CO, VOC, and carbonyl compound...

  14. Thermocatalytic treatment of biomass tar model compounds via radio frequency.

    Science.gov (United States)

    Anis, Samsudin; Zainal, Z A; Bakar, M Z A

    2013-05-01

    A new effective RF tar thermocatalytic treatment process with low energy intensive has been proposed to remove tar from biomass gasification. Toluene and naphthalene as biomass tar model compounds were removed via both thermal and catalytic treatment over a wide temperature range from 850 °C to 1200 °C and 450 °C to 900 °C, respectively at residence time of 0-0.7 s. Thermal characteristics of the new technique are also described in this paper. This study clearly clarified that toluene was much easier to be removed than naphthalene. Soot was found as the final product of thermal treatment of the tar model and completely removed during catalytic treatment. Radical reactions generated by RF non-thermal effect improve the tar removal. The study showed that Y-zeolite has better catalytic activity compared to dolomite on toluene and naphthalene removal due to its acidic nature and large surface area, even at lower reaction temperature of about 550 °C. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Thermal stability of DNA with interstrand crosslinks.

    Science.gov (United States)

    Chang, Chun-Ling; Lando, Dmitri Y; Fridman, Alexander S; Hu, Chin-Kun

    2012-10-01

    Although many anticancer drugs exert their biological activity by forming DNA interstrand crosslinks (ICLs), the thermodynamics of biologically relevant long crosslinked DNAs has not been intensively studied in contrast to short duplexes. Here, we carry out computer modeling of the shift of melting temperature of long DNAs caused by ICLs taking into account crosslinking effect in itself and concomitant local alterations in the free energy (δG) of the helix-coil transition at sites of ICLs. Depending on δG, DNA interstrand crosslinks at per nucleotide concentration r = 0.05 can change the melting temperature by value from -17 to +47°C, and the influence weakly depends on DNA sequence and GC content. A change in melting temperature caused by introduction of interstrand crosslinking in modified DNA at sites of modifications also depends on δG and varies from 0 to +12°C. Comparison with experiment for the three platinum crosslinking compounds demonstrates utility of the theoretical method for understanding how crosslinking compounds can influence the melting behavior. On the basis of the method, interdependence of local distortions and crosslinking in itself was studied for thermal effect of ICLs. A method for evaluating the nature of the structural alteration that produces a change in thermal stability for short crosslinked DNA is also proposed. The methods can be used for comparative thermodynamic characterization of various DNA crosslinking agents. Copyright © 2012 Wiley Periodicals, Inc.

  16. Thermal Anemometry Grid Sensor

    Directory of Open Access Journals (Sweden)

    Martin Arlit

    2017-07-01

    Full Text Available A novel thermal anemometry grid sensor was developed for the simultaneous measurement of cross-sectional temperature and axial velocity distribution in a fluid flow. The sensor consists of a set of platinum resistors arranged in a regular grid. Each platinum resistor allows the simultaneous measurement of fluid temperature via electrical resistance and flow velocity via constant voltage thermal anemometry. Cross-sectional measurement was enabled by applying a special multiplexing-excitation scheme. In this paper, we present the design and characterization of a prototypical sensor for measurements in a range of very low velocities.

  17. Thermal management of batteries

    Science.gov (United States)

    Gibbard, H. F.; Chen, C.-C.

    Control of the internal temperature during high rate discharge or charge can be a major design problem for large, high energy density battery systems. A systematic approach to the thermal management of such systems is described for different load profiles based on: thermodynamic calculations of internal heat generation; calorimetric measurements of heat flux; analytical and finite difference calculations of the internal temperature distribution; appropriate system designs for heat removal and temperature control. Examples are presented of thermal studies on large lead-acid batteries for electrical utility load levelling and nickel-zinc and lithium-iron sulphide batteries for electric vehicle propulsion.

  18. Thermal Anemometry Grid Sensor.

    Science.gov (United States)

    Arlit, Martin; Schleicher, Eckhard; Hampel, Uwe

    2017-07-19

    A novel thermal anemometry grid sensor was developed for the simultaneous measurement of cross-sectional temperature and axial velocity distribution in a fluid flow. The sensor consists of a set of platinum resistors arranged in a regular grid. Each platinum resistor allows the simultaneous measurement of fluid temperature via electrical resistance and flow velocity via constant voltage thermal anemometry. Cross-sectional measurement was enabled by applying a special multiplexing-excitation scheme. In this paper, we present the design and characterization of a prototypical sensor for measurements in a range of very low velocities.

  19. No Thermalization without Correlations

    Science.gov (United States)

    Zhdanov, Dmitry V.; Bondar, Denys I.; Seideman, Tamar

    2017-10-01

    The proof of the long-standing conjecture is presented that Markovian quantum master equations are at odds with quantum thermodynamics under conventional assumptions of fluctuation-dissipation theorems (implying a translation invariant dissipation). Specifically, except for identified systems, persistent system-bath correlations of at least one kind, spatial or temporal, are obligatory for thermalization. A systematic procedure is proposed to construct translation invariant bath models producing steady states that well approximate thermal states. A quantum optical scheme for the laboratory assessment of the developed procedure is outlined.

  20. Thermal Inactivation of Viruses

    Science.gov (United States)

    1977-10-01

    S) VIKU3FS THERMAL RESISTANCE FOODS FLUIDS FOOD PROCESSING FOOD PRESERVATION CONTAMINATION HEAT VIRAL NUCLEIC ACIDS ao’.AjUsTNACT (Conilnum...an rm**— •**» It nmc +nmy m>d Id+atttr by M«o* fmbm) A review of the literature pertaining to thermal inactivation of virus in fluid media» fluid...vacuum packaged in cans or in flexible pouches , frozen to ca. -40 C, and irradiated within a temperature range of -40 C to -8 C to obtain the

  1. Thermal Nanosystems and Nanomaterials

    CERN Document Server

    Volz, Sebastian

    2009-01-01

    Heat transfer laws for conduction, radiation and convection change when the dimensions of the systems in question shrink. The altered behaviours can be used efficiently in energy conversion, respectively bio- and high-performance materials to control microelectronic devices. To understand and model those thermal mechanisms, specific metrologies have to be established. This book provides an overview of actual devices and materials involving micro-nanoscale heat transfer mechanisms. These are clearly explained and exemplified by a large spectrum of relevant physical models, while the most advanced nanoscale thermal metrologies are presented.

  2. Thermal Network Modelling Handbook

    Science.gov (United States)

    1972-01-01

    Thermal mathematical modelling is discussed in detail. A three-fold purpose was established: (1) to acquaint the new user with the terminology and concepts used in thermal mathematical modelling, (2) to present the more experienced and occasional user with quick formulas and methods for solving everyday problems, coupled with study cases which lend insight into the relationships that exist among the various solution techniques and parameters, and (3) to begin to catalog in an orderly fashion the common formulas which may be applied to automated conversational language techniques.

  3. Sensitivity analysis of critical experiments with evaluated nuclear data libraries

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, D.; Kosaka, S. [Tepco Systems Corporation, Nuclear Engineering Dept., Tokyo (Japan)

    2008-07-01

    Criticality benchmark testing was performed with evaluated nuclear data libraries for thermal, low-enriched uranium fuel rod applications. C/E values for k{sub eff} were calculated with the continuous-energy Monte Carlo code MVP2 and its libraries generated from Endf/B-VI.8, Endf/B-VII.0, JENDL-3.3 and JEFF-3.1. Subsequently, the observed k{sub eff} discrepancies between libraries were decomposed to specify the source of difference in the nuclear data libraries using sensitivity analysis technique. The obtained sensitivity profiles are also utilized to estimate the adequacy of cold critical experiments to the boiling water reactor under hot operating condition. (authors)

  4. Fission-Produced99Mo Without a Nuclear Reactor.

    Science.gov (United States)

    Youker, Amanda J; Chemerisov, Sergey D; Tkac, Peter; Kalensky, Michael; Heltemes, Thad A; Rotsch, David A; Vandegrift, George F; Krebs, John F; Makarashvili, Vakho; Stepinski, Dominique C

    2017-03-01

    99 Mo, the parent of the widely used medical isotope 99m Tc, is currently produced by irradiation of enriched uranium in nuclear reactors. The supply of this isotope is encumbered by the aging of these reactors and concerns about international transportation and nuclear proliferation. Methods: We report results for the production of 99 Mo from the accelerator-driven subcritical fission of an aqueous solution containing low enriched uranium. The predominately fast neutrons generated by impinging high-energy electrons onto a tantalum convertor are moderated to thermal energies to increase fission processes. The separation, recovery, and purification of 99 Mo were demonstrated using a recycled uranyl sulfate solution. Conclusion: The 99 Mo yield and purity were found to be unaffected by reuse of the previously irradiated and processed uranyl sulfate solution. Results from a 51.8-GBq 99 Mo production run are presented. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  5. The Rhode Island Nuclear Science Center conversion from HEU to LEU fuel

    Energy Technology Data Exchange (ETDEWEB)

    Tehan, Terry

    2000-09-27

    The 2-MW Rhode Island Nuclear Science Center (RINSC) open pool reactor was converted from 93% UAL-High Enriched Uranium (HEU) fuel to 20% enrichment U3Si2-AL Low Enriched Uranium (LEU) fuel. The conversion included redesign of the core to a more compact size and the addition of beryllium reflectors and a beryllium flux trap. A significant increase in thermal flux level was achieved due to greater neutron leakage in the new compact core configuration. Following the conversion, a second cooling loop and an emergency core cooling system were installed to permit operation at 5 MW. After re-licensing at 2 MW, a power upgrade request will be submitted to the NRC.

  6. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  8. Impact of disorder on ionic charge in spinel compounds

    Science.gov (United States)

    Surblé, Suzy; Baldinozzi, Gianguido; Siméone, David; Gosset, Dominique; Thomé, Lionel

    2008-06-01

    In order to obtain a correlation between the ionic charge and the local environment, the evolution of valence charges of cations in different 2-3 spinel compounds was investigated as a function of the temperature. The evolution of the structural parameters in normal (MgAl2O4), mixed (MgGa2O4) and inverse (MgIn2O4) spinels as a function of the temperature was extracted from X-ray diffraction patterns collected during different thermal annealings. The evolution of these structural parameters as a function of the disorder is analyzed within the bond valence shell model: large variations of the cation valence are observed in these three spinel compounds. From this analysis, a strong correlation between the change of the cation valence and the local disorder is pointed out. Including this dependence in the microscopic models may provide a better agreement between experimental observations and simulations.

  9. Reduction of thermal conductivity by low energy multi-Einstein optic modes

    Directory of Open Access Journals (Sweden)

    Huili Liu

    2016-06-01

    Full Text Available The lattice dynamics and thermal transport in Cu2-δSe compounds were investigated via theoretical calculations, neutron measurement, and characterization of thermal properties. The results show that binary ordered Cu2-δSe has an extremely low lattice thermal conductivity at low temperatures. The low energy multi-Einstein optic modes are the dominant approach obtaining such an extremely low lattice thermal conductivity. It is indicated that the damped vibrations of copper ions could contribute to the low energy multi-Einstein optic modes, especially for those low energy branches at 2–4 meV.

  10. Reversible phase change of new anthracene compounds triggered by the action of light and heat

    Science.gov (United States)

    Kihara, Hideyuki; Yoshida, Masaru

    2014-03-01

    We synthesized 2-anthroyl and 9-anthroyl ester compounds and investigated their bulk-phase changes associated with photodimerization under melting conditions (melt-photodimerization) and subsequent thermal back reactions. All the five anthroyl compounds exhibited melting points lower than ca. 160 °C, and they were nearly quantitatively converted to the corresponding photodimers by UV irradiation in their molten state. Among them, two 2-anthroyl compounds remained isotropic and lost fluidity during the melt-photodimerization. The obtained photodimers exhibited robust solid-state amorphous phases at room temperature. In contrast, the other three anthroyl compounds showed crystallization during the melt-photodimerization. It was also found that the photodimers returned to the corresponding monomers by heat. We successfully demonstrated rewritable photopatterning using the phase change of the anthracene compounds triggered by the action of light and heat.

  11. Thermoelectric properties of SnSe compound

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Xinhong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Lu, Pengfei, E-mail: photon@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Wu, Liyuan; Han, Lihong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Liu, Gang [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Song, Yuxin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Shumin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    2015-09-15

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data.

  12. The effect of sonication on bioactive compounds in carrot juice

    Directory of Open Access Journals (Sweden)

    A Ayaseh

    2016-01-01

    Full Text Available The objective of this research was to determine the effect of ultrasound treatment on bioactive compounds (including total phenolic, total flavonoids, total carotenoids, ascorbic acid of carrot juice in comparison with conventional thermal process. Carrot juice samples were sonicated according to D-optimal response surface design with processing variables of temperature (25, 37.5 and 50°C, time (10, 20 and 30 min and power (350 and 400 w at a constant frequency of 24 kHz. Results showed that ultrasound temperature (P

  13. Safety of food contact silicone rubber: Liberation of volatile compounds from soothers and teats

    DEFF Research Database (Denmark)

    Lund, Kirsten H.; Petersen, Jens Højslev

    2002-01-01

    C were observed using gravimetric measurements. One product had a weight loss above the proposed CEN limit of 0.5%. Secondly, the volatile compounds were identified using a thermal desorption/cold trap injector on a gas chromatograph equipped with infrared spectroscopic (IR) and mass spectrometric (MS...

  14. Synthesis, Structure and Properties of Melamine-Based pTHF-Urethane Supramolecular Compounds

    NARCIS (Netherlands)

    Öjelund, Karin; Loontjens, Ton; Steeman, Paul; Palmans, Anja; Maurer, Frans

    2003-01-01

    The properties of melamine based supramolecular compounds have been studied with rheological, thermal, mechanical, dielectric and scattering techniques and compared with similar covalently bonded materials. The complexes are based on a linear pTHF-diol (M¯n=1 000) connected via a diisocyanate with

  15. SYNTHESIS, CRYSTAL STRUCTURE, SPECTROSCOPY PROPERTIES AND POTENTIAL ANTIMICROBIAL POTENTIALITIES OF A NEW SYNTHETIC COMPOUND: AMINO- CHLOROPYRIDINIUM DIAQUA DIOXALATO IRON(III)

    National Research Council Canada - National Science Library

    Jawher Abdelhak; Essghaier Badiaa; Toukebri Nourchene; Amani Naouar; Rebib Hanene; Mohamed Faouzi Zid; Najla Sadfi-Zouaoui

    .... It has been characterized by IR and UV-VIS spectra and thermal analysis (TG and DTA). In this compound, the iron ion has a slightly distorted square bipyramidal environment, coordinated by two chelating oxalate ion and two water molecules...

  16. Thermal management for LED applications

    CERN Document Server

    Poppe, András

    2014-01-01

    Thermal Management for LED Applications provides state-of-the-art information on recent developments in thermal management as it relates to LEDs and LED-based systems and their applications. Coverage begins with an overview of the basics of thermal management including thermal design for LEDs, thermal characterization and testing of LEDs, and issues related to failure mechanisms and reliability and performance in harsh environments. Advances and recent developments in thermal management round out the book with discussions on advances in TIMs (thermal interface materials) for LED applications, advances in forced convection cooling of LEDs, and advances in heat sinks for LED assemblies. This book also: Presents a comprehensive overview of the basics of thermal management as it relates to LEDs and LED-based systems Discusses both design and thermal management considerations when manufacturing LEDs and LED-based systems Covers reliability and performance of LEDs in harsh environments Has a hands-on applications a...

  17. Shape memory thermal conduction switch

    Science.gov (United States)

    Vaidyanathan, Rajan (Inventor); Krishnan, Vinu (Inventor); Notardonato, William U. (Inventor)

    2010-01-01

    A thermal conduction switch includes a thermally-conductive first member having a first thermal contacting structure for securing the first member as a stationary member to a thermally regulated body or a body requiring thermal regulation. A movable thermally-conductive second member has a second thermal contacting surface. A thermally conductive coupler is interposed between the first member and the second member for thermally coupling the first member to the second member. At least one control spring is coupled between the first member and the second member. The control spring includes a NiTiFe comprising shape memory (SM) material that provides a phase change temperature <273 K, a transformation range <40 K, and a hysteresis of <10 K. A bias spring is between the first member and the second member. At the phase change the switch provides a distance change (displacement) between first and second member by at least 1 mm, such as 2 to 4 mm.

  18. Anisotropic Thermal Diffusivities of Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Akoshima, Megumi; Takahashi, Satoru

    2017-09-01

    Thermal barrier coatings (TBCs) are used to shield the blades of gas turbines from heat and wear. There is a pressing need to evaluate the thermal conductivity of TBCs in the thermal design of advanced gas turbines with high energy efficiency. These TBCs consist of a ceramic-based top coat and a bond coat on a superalloy substrate. Usually, the focus is on the thermal conductivity in the thickness direction of the TBC because heat tends to diffuse from the surface of the top coat to the substrate. However, the in-plane thermal conductivity is also important in the thermal design of gas turbines because the temperature distribution within the turbine cannot be ignored. Accordingly, a method is developed in this study for measuring the in-plane thermal diffusivity of the top coat. Yttria-stabilized zirconia top coats are prepared by thermal spraying under different conditions. The in-plane and cross-plane thermal diffusivities of the top coats are measured by the flash method to investigate the anisotropy of thermal conduction in a TBC. It is found that the in-plane thermal diffusivity is higher than the cross-plane one for each top coat and that the top coats have significantly anisotropic thermal diffusivity. The cross-sectional and in-plane microstructures of the top coats are observed, from which their porosities are evaluated. The thermal diffusivity and its anisotropy are discussed in detail in relation to microstructure and porosity.

  19. Cancer prevention with natural compounds.

    Science.gov (United States)

    Gullett, Norleena P; Ruhul Amin, A R M; Bayraktar, Soley; Pezzuto, John M; Shin, Dong M; Khuri, Fadlo R; Aggarwal, Bharat B; Surh, Young-Joon; Kucuk, Omer

    2010-06-01

    Botanical and nutritional compounds have been used for the treatment of cancer throughout history. These compounds also may be useful in the prevention of cancer. Population studies suggest that a reduced risk of cancer is associated with high consumption of vegetables and fruits. Thus, the cancer chemopreventive potential of naturally occurring phytochemicals is of great interest. There are numerous reports of cancer chemopreventive activity of dietary botanicals, including cruciferous vegetables such as cabbage and broccoli, Allium vegetables such as garlic and onion, green tea, Citrus fruits, soybeans, tomatoes, berries, and ginger, as well as medicinal plants. Several lead compounds, such as genistein (from soybeans), lycopene (from tomatoes), brassinin (from cruciferous vegetables), sulforaphane (from asparagus), indole-3-carbinol (from broccoli), and resveratrol (from grapes and peanuts) are in preclinical or clinical trials for cancer chemoprevention. Phytochemicals have great potential in cancer prevention because of their safety, low cost, and oral bioavailability. In this review, we discuss potential natural cancer preventive compounds and their mechanisms of action. 2010 Elsevier Inc. All rights reserved.

  20. The Compound Atwood Machine Problem

    Science.gov (United States)

    Coelho, R. Lopes

    2017-01-01

    The present paper accounts for progress in physics teaching in the sense that a problem, which has been closed to students for being too difficult, is gained for the high school curriculum. This problem is the compound Atwood machine with three bodies. Its introduction into high school classes is based on a recent study on the weighing of an…