WorldWideScience

Sample records for high temperature polymeric

  1. High temperature structural, polymeric foams from high internal emulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Hoisington, M.A.; Duke, J.R.; Apen, P.G.

    1996-02-01

    In 1982, a high internal phase emulsion (HIPE) polymerization process to manufacture microcellular, polymeric foam systems was patented by Unilever. This patent discloses a polymerization process that occurs in a water-in-oil emulsion in which the water represents at least 76% of the emulsion by volume. The oil phase consists of vinyl monomers such as styrene and acrylates that are crosslinked by divinyl monomers during polymerization. After polymerization and drying to remove the water phase, the result is a crosslinked polymer foam with an open cell microstructure that is homogeneous throughout in terms of morphology, density, and mechanical properties. Since 1982, numerous patents have examined various HIPE polymerized foam processing techniques and applications that include absorbents for body fluids, cleaning materials, and ion exchange systems. All the published HIPE polymerized foams have concentrated on materials for low temperature applications. Copolymerization of styrene with maleic anhydride and N-substituted maleimides to produce heat resistant thermoplastics has been studied extensively. These investigations have shown that styrene will free radically copolymerize with N-substituted maleimides to create an alternating thermoplastic copolymer with a Tg of approximately 200{degrees}C. However, there are many difficulties in attempting the maleimide styrene copolymerization in a HIPE such as lower polymerization temperatures, maleimide solubility difficulties in both styrene and water, and difficulty obtaining a stable HIPE with a styrene/maleimide oil phase. This work describes the preparation of copolymer foams from N-ethylmaleimide and Bis(3-ethyl-5-methyl-4-maleimide-phenyl)methane with styrene based monomers and crosslinking agents.

  2. High-temperature-pressure Polymerized Resin-infiltrated Ceramic Networks

    Science.gov (United States)

    Nguyen, J.F.; Ruse, D.; Phan, A.C.; Sadoun, M.J.

    2014-01-01

    The aim of this study was to produce composite blocks (CB) for CAD/CAM applications by high-temperature-pressure (HT/HP) polymerization of resin-infiltrated glass-ceramic networks. The effect of network sintering and the absence/presence of initiator was investigated. Mechanical properties were determined and compared with those of Paradigm MZ100 (3M ESPE) blocks and HT/HP polymerized experimental “classic” CB, in which the filler had been incorporated by conventional mixing. The networks were made   from glass-ceramic powder (VITA Zahnfabrik) formed by slip casting and were either sintered or not. They were silanized, infiltrated by urethane dimethacrylate, with or without initiator, and polymerized under HT/HP (300 MPa, 180°C) to obtain resin-infiltrated glass-ceramic network (RIGCN) CB. HT/HP polymerized CB were also made from an experimental “classic” composite. Flexural strength (σf), fracture toughness (KIC), and Vickers hardness were determined and analyzed by one- or two-way analysis of variance (ANOVA), Scheffé multiple-means comparisons (α = 0.05), and Weibull statistics (for σf). Fractured surfaces were characterized with scanning electron microscopy. The mechanical properties of RIGCN CB were significantly higher. Sintering induced significant increases in σf and hardness, while the initiator significantly decreased hardness. The results suggested that RIGCN and HT/HP polymerization could be used to obtain CB with superior mechanical properties, suitable for CAD/CAM applications. PMID:24186559

  3. Matrix free fiber reinforced polymeric composites via high-temperature high-pressure sintering

    Science.gov (United States)

    Xu, Tao

    2004-11-01

    A novel manufacturing process called high-temperature high-pressure sintering was studied and explored. Solid fiber reinforced composites are produced by consolidating and compacting layers of polymeric fabrics near their melting temperature under high pressure. There is no need to use an additional matrix as a bonding material. Partial melting and recrystallization of the fibers effectively fuse the material together. The product is called a "matrix free" fiber reinforced composite and essentially a one-polymer composite in which the fiber and the matrix have the same chemical composition. Since the matrix is eliminated in the process, it is possible to achieve a high fiber volume fraction and light weight composite. Interfacial adhesion between fibers and matrix is very good due to the molecular continuity throughout the system and the material is thermally shapeable. Plain woven Spectra RTM cloth made of SpectraRTM fiber was used to comprehensively study the process. The intrinsic properties of the material demonstrate that matrix free SpectraRTM fiber reinforced composites have the potential to make ballistic shields such as body armor and helmets. The properties and structure of the original fiber and the cloth were carefully examined. Optimization of the processing conditions started with the probing of sintering temperatures by Differential Scanning Calorimetry. Coupled with the information from structural, morphological and mechanical investigations on the samples sintered at different processing conditions, the optimal processing windows were determined to ensure that the outstanding original properties of the fibers translate into high ballistic performance of the composites. Matrix free SpectraRTM composites exhibit excellent ballistic resistance in the V50 tests conducted by the US Army. In the research, process-structure-property relationship is established and correlations between various properties and structures are understood. Thorough knowledge is

  4. Polymerization Experiment Of Amino Acids Under High Pressure And Temperature Conditions Simulating The Deep Lithosphere

    Science.gov (United States)

    Ohara, S.; Kakegawa, T.; Nakazawa, H.

    2005-12-01

    Chemical evolution in deep sea or deep lithosphere is one of the popular hypotheses for the origin of life on the early Earth. In such hypothesis, effects of pressure and temperature on polymerization (and/or stability) of amino acids needed to be evaluated. In this study, high temperature and pressure experiments were performed using of a test-tube-type autoclave for polymerization of amino acids. Approximately 100 mg of Glycine powder were placed into sterilized gold capsule. Multiple experiments were done at 150 degrees for 1 to 8 days at variable pressures (25MPa, 50MPa, 75MPa and 100MPa). Glycine peptides were identified and quantified by high performance liquid chromatography (HPLC). Each capsule was opened carefully and 1 ml of mobile phase was added to release the amino acids and oligopeptide from the solid phase. Liquid phases were separated by the cetrifugal method. Peptides were identified by retention times of authentic reference substances. The reaction yields were determined as percentage of the reactant converted to the reaction product. Pligopeptides more than hexamer were additionally identified by the detection of the molecular ion by liquid chromatography mass spectrometry (LC / MS). A HPLC chromatogram of the products indicated at least seven oligomers: diketopiperazine (cyc(Gly)2), di-glycine (Gly2), tri-glycine (Gly3), tetra-glycine (Gly4), penta-glycine (Gly5) and hexa-glycine (Gly6). We also identified hepta-glycine (Gly7), octa-glycine (Gly8) and nona-glycine (Gly9) with LC/MS. This is the first report that up to nona-glycine was synthesized under high temperature and pressure conditions. In addition, our experiments indicate that polymerization occurs wide range of pressure from 25 to 100 MPa. On the other hand, yields of total amounts of peptide did not change with pressure, suggesting that an unknown process in the autoclave is limiting the yield. We speculate the activity of water vapor, generated by peptide formation reaction

  5. Decay Time Measurement for Different Energy Depositions of Plastic Scintillator Fabricated by High Temperature Polymerization Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheol Ho; Son, Jaebum; Lee, Sangmin; Kim, Tae Hoon; Kim, Yong-Kyun [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    Plastic scintillators are based on organic fluorite. They have many advantages such as fast rise and decay time, high optical transmission, ease of manufacturing, low cost, and large available size. For these reasons they are widely used for particle identification. Also, protection of people against a variety of threats (such as nuclear, radiological, and explosive) represents a true challenge along with the continuing development of science and technology. The plastic scintillator is widely used in various devise, which serves for nuclear, photonics, quantum, and high-energy physics. The plastic scintillator is probably the most widely used organic detector, and polystyrene is one of the most widely used materials in the making of the plastic scintillator detector. Thus, a styrene monomer as a solvent was used to fabricate the plastic scintillator by using high temperature polymerization reaction, and then the emission wavelength and the decay times for different energy depositions were measured by using the fabricated plastic scintillator. A plastic scintillator was fabricated to measure decay time for different energy depositions using the high temperature polymerization. Emission wavelength was measured of 426.05 nm to confirm a scintillator property using the spectrophotometer. Four gamma-ray sources (Cs-137, Co-60, Na-22, and Ba-133) were used to evaluate effect for decay time of different energy depositions. The average decay time of the fabricated plastic scintillator was measured to approximately 4.72 ns slightly higher more than commercial plastic scintillator. In future, light output and linearity will be measured to evaluate other property compared with the commercial scintillator.

  6. Synthesis of polystyrene with high melting temperature through BDE/CuCl catalyzed polymerization

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    No matter what the polymerization manner was, polystyrene withunique high Tm (Tm = 170-285℃) was obtained through polymerization of styrene if the amount of BDE/CuCl catalyst was highly increased (mol ratio: St:CuCl = 25:1-2.5:1). Partial crystallinity of the PSt was observed by characterizations of X-ray diffraction and DSC. Spectra of 1H-NMR and 13C-NMR showed that syndiotactic structure contained in the obtained PSt was 5% more than that in aPSt (atactic polystyrene). According to the proposed "coordinated radical cage" mechanism, the coordinated state between radical and catalyst center metal Cu should be more closely packed with increasing the BDE/CuCl catalyst amount, which was induced to partial stereospecific polymerization in the coordinated radical polymerization of St.

  7. How do polymerized room-temperature ionic liquid membranes plasticize during high pressure CO2 permeation?

    NARCIS (Netherlands)

    Simons, K.; Nijmeijer, D.C.; Bara, J.B.; Noble, R.D.; Wessling, M.

    2010-01-01

    Room-temperature ionic liquids (RTILs) are a class of organic solvents that have been explored as novel media for CO2 separations. Polymerized RTILs (poly(RTILs)) can be synthesized from RTIL monomers to form dense, solid gas selective membranes. It is of interest to understand the permeation proper

  8. Effects of High-Temperature-Pressure Polymerized Resin-Infiltrated Ceramic Networks on Oral Stem Cells.

    Directory of Open Access Journals (Sweden)

    Mathilde Tassin

    Full Text Available The development of CAD-CAM techniques called for new materials suited to this technique and offering a safe and sustainable clinical implementation. The infiltration of resin in a ceramic network under high pressure and high temperature defines a new class of hybrid materials, namely polymer infiltrated ceramics network (PICN, for this purpose which requires to be evaluated biologically. We used oral stem cells (gingival and pulpal as an in vitro experimental model.Four biomaterials were grinded, immersed in a culture medium and deposed on stem cells from dental pulp (DPSC and gingiva (GSC: Enamic (VITA®, Experimental Hybrid Material (EHM, EHM with initiator (EHMi and polymerized Z100™ composite material (3M®. After 7 days of incubation; viability, apoptosis, proliferation, cytoskeleton, inflammatory response and morphology were evaluated in vitro.Proliferation was insignificantly delayed by all the tested materials. Significant cytotoxicity was observed in presence of resin based composites (MTT assay, however no detectable apoptosis and some dead cells were detected like in PICN materials. Cell morphology, major cytoskeleton and extracellular matrix components were not altered. An intimate contact appeared between the materials and cells.The three new tested biomaterials did not exhibit adverse effects on oral stem cells in our experimental conditions and may be an interesting alternative to ceramics or composite based CAD-CAM blocks.

  9. Highly Efficient and Well-controlled Ambient Temperature Raft Polymerization Under Visible Light Radiation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results A range of well-defined polymers and their corresponding block copolymers were synthesized via ambient temperature RAFT polymerization under environmentally friendly visible light radiation,using a (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) photo-initiator[1].The results indicated that the photolysis of chain transfer agent (CTA) functionalities was significantly suppressed under visible light radiation,thus exerting well control over RAFT process,leading to a remarkably living beh...

  10. Synthesis of polystyrene with high melting temperature through BDE/CuCl catalyzed polymerization

    Institute of Scientific and Technical Information of China (English)

    WAN; Xiaolong

    2001-01-01

    [1]Ewen, J. A., Novel method for plastic production, Science (in Chinese), 1997, 9: 34.[2]Brintzinger, H. H., Fischer, D., Waymouth, R. M. et al., Stereospecific olefin polymerization with chiral metallocene catalysts, Angewandte Chemie International Edition in English, 1995, 34(11): 1143.[3]Matyjaszewski, K., Atom transfer radical polymerization, role of various components and reaction conditions, Polym. Prep., 1997, 38(2): 736.[4]Wang, J. S., Matyjaszewski, K., Controlled/"living" radical polymerization, atom transfer radical polymerization in the presence of transition-metal complex, J. Am. Soc., 1995, 117: 5614.[5]Wang, J. S., Matyjaszewski, K., Controlled/"living" radical polymerization, halogen atom transfer radical polymerization promoted by a Cu(I)/Cu(II) redox process, Macromolecules, 1995, 28: 7901.[6]Koto, M., Kamigaito, M., Sawamoto, M. et al., Polymerization of methyl methacrylate with the carbon tetrachloride/dichloro-tris(triphenyphosphine) ruthenium(II)/methylaluminum bis(2,6-di-tert-butylphenoxide) initiating system: possible of living radical polymerization, Macromolecules, 1995, 28: 1721.[7]Ando, T., Kato, M., Living radical polymerization of methyl methacrylate with Ruthenium complex: formation of polymers with controlled molecular weights and very narrow distributions, Macromolecules, 1996, 29: 1070.[8]Granel, C., Dubios, P., Jerome, R. et al., Controlled radical polymerization of methacrylic monomers in the presence of a bis(ortho-chelated) arylnickel(II) complex and different activated alkyl halides, Macromolecules, 1996, 29: 8576.[9]Granel, C., Moineau, G., Lecome, P. et al., (Meth)acrylates pseudo-living radical polymerization in the presence of transition metal complexes: the kharasch reaction revisited, Polym. Prep., 1997, 38(1): 450.[10]Ando, T., Kamigaito, M., Sawamoto, M., Iron(II) chloride complex for living radical polymerization of methyl methacrylate, Macromolecules, 1997, 30: 4507.[11

  11. Rapid room temperature solubilization and depolymerization of polymeric lignin at high loadings

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jian; Dutta, Tanmoy; Parthasarathi, Ramakrishnan; Kim, Kwang Ho; Tolic, Nikola; Chu, Rosalie K.; Isern, Nancy G.; Cort, John R.; Simmons, Blake A.; Singh, Seema

    2016-10-03

    The relatively poor solubility of lignin in most pretreatment solvents remains one of the biggest challegnes in lignin valorization to improve overall biorefinery economics. In this work, rapid room temperature solubilization of lignin at high solid loadings (>30 wt%) can be easily achieved in a single step using ethylene glycol (EG). The solubilized lignin can be rapidly and quantitively recovered with the addtion of ethanol. The computational and nuclear magnetic resonance (NMR) spectroscopic studies confirm that strong hydrogen bond interactions between EG and the free hydroxyl groups present in lignin contribute to the lignin dissolution. In addition, hydrogen peroxide mediated depolymerization of dissolved lignin at low temperature (80 oC) was tested and the effect of EG molecules on depolymerization of ligin was also theoritically studied. The findings of this work provide mechanistic insights of hydrogen bond interactions in high lignin solubilization and valorization.

  12. Topochemical 3D polymerization of C60 under high pressure at elevated temperatures.

    Science.gov (United States)

    Yamanaka, Shoji; Kini, Nagesh S; Kubo, Akira; Jida, Saeko; Kuramoto, Hideaki

    2008-04-02

    Fullerene C60 monomer crystals were compressed to a face-centered cubic (fcc) phase with a lattice parameter of a = 11.93(5) A and a micro-Vickers hardness of 4500 kg/mm2 using high-pressure and high-temperature conditions of 15 GPa at 500-600 degrees C. The hardness is compatible with that of cubic boron nitride (c-BN), suggesting the formation of a 3D C60 polymer. The single-crystal X-ray structural analysis revealed that each C60 molecule in the polymer was linked to the 12 nearest neighbors by [2+2] cycloaddition between the common pentagon-hexagon (56) edges. However, ab initio geometry optimization and molecular dynamics calculations suggested that the 3D polymer should have a rhombohedral structure with the space group of R containing [3+3] cycloaddition between the pentagons of C60 molecules within the plane perpendicular to the 3-fold axis. The higher apparent symmetry of fcc was observed as an averaged structure of different orientations of the rhombohedral structure. The R structure can be derived by only a slight rotation of each C60 unit in the (111) plane of the fcc structure. The band-structure calculation suggested that the 3D polymer (R) was a semiconductor; the activation energy for the electrical conductivity was experimentally determined to be 0.25 eV at 550 K.

  13. Standard Test Method for Testing Polymeric Seal Materials for Geothermal and/or High Temperature Service Under Sealing Stress

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1985-01-01

    1.1 This test method covers the initial evaluation of (screening) polymeric materials for seals under static sealing stress and at elevated temperatures. 1.2 This test method applies to geothermal service only if used in conjunction with Test Method E 1068. 1.3 The test fluid is distilled water. 1.4 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  14. A Novel RAFT Polymerization under UV Radiation at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Nianfa Yang; Lican Lu; Yuanli Cai

    2005-01-01

    @@ 1Introduction Reversible Addition Fragmentation chain Transfer (RAFT) polymerization has become a highly versatile technique for the controlled/"living" radical polymerization of a wide range of monomers under various conditions[1,2]. The RAFT polymerization was carried out using a dithiocarboxylate or trithiocarbonate as a Chain Transfer Agent (CTA), which mediates the growing chain radicals via an equilibrium[1,2]. From both academic and industrial standpoints, it is clearly desirable to develop a RAFT process under mild conditions. Rizzardo, et al [3] and McCormick's group[4] have respectively reported RAFT polymerization using conventional radical initiators at ambient temperature by adjusting the structure of CTA. The RAFT Polymerization initiated by γ-radiation has also reported recently[5]. Quinn, et al [6] have reported the RAFT polymerization under UV radiation using CTA as the source of primary radicals at 42 ℃, which was well controlled at low conversions (below 20% ) but less controlled at higher conversions (over 20% ) due to the photolysis of CTA residues under UV radiation.

  15. The effect of high temperature sol-gel polymerization parameters on the microstructure and properties of hydrophobic phenol-formaldehyde/silica hybrid aerogels.

    Science.gov (United States)

    Seraji, Mohamad Mehdi; Sameri, Ghasem; Davarpanah, Jamal; Bahramian, Ahmad Reza

    2017-05-01

    Phenol-formaldehyde/silica hybrid aerogels with different degree of hydrophobicity were successfully synthesized via high temperature sol-gel polymerization. Tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) were used as precursor and co-precursor of the hydrophobic silica-based phase, respectively. The hydrolysis step of silica based sols were conducted by acid catalyzed reactions and HCl was used as hydrolysis catalyst. The chemical structure of prepared hybrid aerogels was characterized by Fourier Transform Infrared spectroscopy (FT-IR). The effect of MTES/TEOS proportion and catalyst content on the morphology and microstructure of samples were investigated by FE-SEM and C, Si mapping analysis. The acid catalyzed hydrolysis of TEOS and MTES sols leads to formation of a sol with primarily silica particles in the organic-inorganic hybrid sol and varying colloid growth mechanisms were occurred with change in MTES and HCl molar ratio. With the increasing of MTES content, the microstructure of samples changed from uniform colloidal network, core-shell structure to polymeric structure with a huge phase separation. The increasing of HCl mole fraction leads to smaller particle size. Moreover, the shrinkage of samples was decreased and water contact angles of the resulted aerogels were increased from 40 to 156.8° with the increases of MTES content.

  16. THE POLYMERIZATION OF ROOM TEMPERATURE CURING EPOXY RESINS

    Science.gov (United States)

    EPOXY RESINS , *PLASTICS, *POLYMERIZATION, AGING (PHYSIOLOGY), CHEMICAL BONDS, ELECTRICAL PROPERTIES, EMBEDDING SUBSTANCES, MONITORS, POLYMERS, RESISTANCE (ELECTRICAL), STORAGE, STRUCTURES, TEMPERATURE, TEST METHODS, VOLUME

  17. High Vacuum Techniques for Anionic Polymerization

    KAUST Repository

    Ratkanthwar, Kedar

    2015-09-01

    Anionic polymerization high vacuum techniques (HVTs) are the most suitable for the preparation of polymer samples with well-defined complex macromolecular architectures. Though HVTs require glassblowing skill for designing and making polymerization reactor, it is the best way to avoid any termination of living polymers during the number of steps for the synthesis of polymers with complex structure. In this chapter, we describe the different polymerization reactors and HVTs for the purification of monomers, solvents, and other reagents for anionic polymerization as well as few model reactions for the synthesis of polymers with simple to complex structure.

  18. Manganese sequestration and improved high-temperature cycling of Li-ion batteries by polymeric aza-15-crown-5

    Science.gov (United States)

    Li, Zicheng; Pauric, Allen D.; Goward, Gillian R.; Fuller, Timothy J.; Ziegelbauer, Joseph M.; Balogh, Michael P.; Halalay, Ion C.

    2014-12-01

    Mn cation trapping by polymeric aza-15-crown-5 ethers is an effective means for mitigating the consequences of Mn dissolution in Li-ion batteries. Mn cations trapping was investigated in lithium manganese oxide (LMO) spinel-graphite (GR) cells containing 1 M LiPF6 in ethylene carbonate (EC):diethyl carbonate (DEC) 1:2 v/v. A commercial polyolefin separator membrane coated with poly[divinylbenzene-(vinylbenzyl-aza-15-crown-5)-vinylbenzylchloride)] effected a 39% reduction in capacity loss rate during cycling at 50 °C with 100% depth of discharge (DOD) at C/5 rate. Simultaneously, a 50-60% reduction in the Mn deposited at the negative electrode, and a 6× to 10× increase in the Mn on the coated separator were observed for cells with coated separators, over baseline cells with plain separators. X-ray absorption near-edge spectroscopy (XANES) yielded average oxidation states near +3 for Mn cations in graphite electrodes and separators from cycled cells, suggesting that Mn metal or in oxidation state +2 can only be minor fractions of the Mn existing outside the positive electrode. We discuss the implications of these results for choosing an optimal chelating agent. We also show that the cation chelating polymer reported here is compatible with existing manufacturing processes for Li-ion battery separators.

  19. Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

    Institute of Scientific and Technical Information of China (English)

    YANG XiongFa; NI XuFeng; SHEN ZhiQuan

    2009-01-01

    The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H_2salen)_2Cl_3·2C_2H_7OH/Al(i-Bu)_3) at room temperature was investigated.The influences of ligand structure,catalyst composition,polymerization temperature,polymerization time,the concentration of catalyst and monomer,and the polymerization solvent on the polymerization of isocyanates were studied.It was found that under the polymerization conditions,examined La(H_2salen_A)_2Cl_3·2C_(2-)H_7OH/Al(i-Bu)_3 (H_2salen_A=N,N'-disalicylideneethylene diamine) is a fairly high efficient catalyst for the polymerization of n-hexyl isocyanate (n-HexNCO) to prepare high molecular weight poly(n-hexyl isocyanate) (PHNCO) with narrower molecular weight distribution at room temperature.PHNCO could be prepared with yield of 74.0%,number-average molecular weight (M_n) of 40.20×10~4 and MWD of 1.79 under the following optimum conditions:[Al]/[La]=30 (molar ratio),[n-HexNCO]/[La]=100 (molar ratio),[n-HexNCO]=3.43 mol/L polymerization at 20℃ for 12 h in toluene.In the same polymerization conditions,poly (n-octyl isocyanate) (PONCO) with yield of 67.3%,and poly(n-butyl isocyanate) (PBNCO) with yield of 45.5%,could be prepared respectively.The kinetics of the polymerization of n-HexNCO was also investigated and found to be first-order with respect to both monomer and catalyst concentrations.

  20. COPPER(0)-MEDIATED RADICAL POLYMERIZATION OF STYRENE AT ROOM TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    Xiao-fei Zhang; Yang Wu; Jun Huang; Xue-lang Miao; Zheng-biao Zhang; Xiu-lin Zhu

    2013-01-01

    The "living'/controlled radical polymerization (LRP) of styrene (St) at room temperature is rarely reported.In this work,copper(0) (Cu(0))-mediated radical polymerization of St at room temperature was investigated in detail.Dimethyl sulfoxide (DMSO),N,N-dimethylformamide (DMF) as well as a binary solvent,tetrahydrofuran/1,1,1,3,3,3-hexafluoro-2-propanol were used as the solvents,respectively.Methyl-2-bromopropionate and ethyl 2-bromoisobutyrate were used as the initiators,respectively.The polymerization proceeded smoothly with moderate conversions at room temperature.It was found that DMF was a good solvent with the essential features of LRP,while DMSO was a poor solvent with uncontrollable molecular weights.Besides,the match among the initiator,solvent and molar ratios of reactants can modulate the livingness of the polymerization,and the proper selection of ligand was also crucial to a controlled process.This work provided a first example of Cu(0)-mediated radical polymerization of St at room temperature,which would enrich and strength the LRP technique.

  1. Multifunctional Benzoxazines Feature Low Polymerization Temperature and Diverse Polymer Structures

    Directory of Open Access Journals (Sweden)

    Marc Soto

    2016-08-01

    Full Text Available 3,4-dihydro-3-phenyl-2H-1,3-benzoxazines derived from phenol-, resorcinol-, and phloroglucinol give monomers with one, two, and three oxazine units at a single benzene ring, respectively. Aside from the synthesis and characterization of such multifunctional benzoxazines, reactivity and polymerization behavior is studied in dependence of the oxazine functionality. Monomer reactivities are directly related to the number of oxazine functionalities present at the benzene ring yielding the lowest polymerization temperature for the trifunctional phloroglucinol-based benzoxazine. Comparing the polymerization processes and resulting structures, the trifunctional benzoxazine derivative enter new polymerization pathways, which include methylene linkages bridging aniline units, as well as the formation of carbonyl-derived structures.

  2. High-Performance Polymeric Materials.

    Science.gov (United States)

    1987-12-07

    interactions, Chain packing, Polybenzobisoxazoles Electrical conductivity Polybenzobisthiazoles Ceramic particles Chain flexibility Elastomer reinforcement...structures for the polybenzobisoxazole (PBO) and polybenzobisthiazole (PBT) chains originally synthesized and much studied because of their utility as...high-performance fibers and films. For cts-PBO, trans-PBO. and trans-PBT chains in their coplanar conformations, the band gaps in the axial direction

  3. Highly efficient solid-state dye-sensitized solar cells based on hexylimidazolium iodide ionic polymer electrolyte prepared by in situ low-temperature polymerization

    Science.gov (United States)

    Wang, Guiqiang; Yan, Chao; Zhang, Juan; Hou, Shuo; Zhang, Wei

    2017-03-01

    Solid-state dye-sensitized solar cells (DSCs) are fabricated using a novel ionic polymer electrolyte containing hexylimidazolium iodide (HII) ionic polymer prepared by in situ polymerization of N,N‧-bis(imidazolyl) hexane and 1,6-diiodohexane without an initiator at low temperature (40 °C). The as-prepared HII ionic polymer has a similar structure to alkylimidazolium iodide ionic liquid, and the imidazolium cations are contained in the polymer main chain; so, it can act simultaneously as the redox mediator in the electrolyte. By incorporating an appropriate amount of 1,3-dimethylimidazolium iodide (DMII) in HII ionic polymer (DMII/HII ionic polymer = 0.7:1, weight ratio), the conductivity of the ionic polymer electrolyte is greatly improved due to the formation of Grotthuss bond exchange. In addition, in situ synthesis of ionic polymer electrolyte guarantees a good pore-filling of the electrolyte in the TiO2 photoanode. As a result, the solid-state DSC based on the ionic polymer electrolyte containing HII ionic polymer and DMII without iodine achieves a conversion efficiency of 6.55% under the illumination of 100 mW cm-2 (AM 1.5), which also exhibits a good at-rest stability at room temperature.

  4. Effect of temperature on the mechanism of actin polymerization.

    Science.gov (United States)

    Zimmerle, C T; Frieden, C

    1986-10-21

    The rate of the Mg2+-induced polymerization of rabbit skeletal muscle G-actin has been measured as as function of temperature at pH 8 by using various concentrations of Mg2+, Ca2+, and G-actin. A polymerization mechanism similar to that proposed at this pH [Frieden, C. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 6513-6517] was found to fit the data from 10 to 35 degrees C. From the kinetic data, no evidence for actin filament fragmentation was found at any temperature. Dimer formation is the most temperature-sensitive step, with the ratio of forward and reverse rate constants changing 4 orders of magnitude from 10 to 35 degrees C. Over this temperature change, all other ratios of forward and reverse rate constants change 7-fold or less, and the critical concentration remains nearly constant. The reversible Mg2+-induced isomerization of G-actin monomer occurs to a greater extent with increasing temperature, measured either by using N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine-labeled actin or by simulation of the full-time course of the polymerization reaction. This is partially due to Mg2+ binding becoming tighter, and Ca2+ binding becoming weaker, with increasing temperature. Elongation rates from the filament-pointed end, determined by using actin nucleated by plasma gelsolin, show a temperature dependence slightly larger than that expected for a diffusion-limited reaction.

  5. Polymeric electrolytes for ambient temperature lithium batteries

    Science.gov (United States)

    Farrington, G. C.

    1987-09-01

    During this reporting period a number of novel solid polymer electrolytes formed by salts of multivalent cations and polyethylene oxide (PEO) have been prepared and characterized. These materials are of interest not only because of their potential ionic conductivities, but also because some of them may have electronic conductivity and oxidizing power which would be useful for novel electrode materials in all-solid-state batteries. Two broad classes of materials were investigated: PEO solutions of Zn(2), Cd(2), and Pb(2), all of which are potential electrolytes for solid-state batteries, and PEO solutions of transition metal salts, which are of interest as possible cathode materials. Mixed compositions containing both divalent cations and lithium ions were also prepared. Electrolytes formed with small, highly-polarizing ions, such as Mg(2) and Ca(2), are essentially pure anion conductors. Electrolytes containing Zn(2) behave similarly, unless they are hydrated, in which case the Zn(2) ions are quite mobile. Electrolytes formed with larger, more polarizable cations, such as Pb(2) and Cd(2), conduct both anions and cations. Solutions of salts of transition metal cations form a third group of electrolytes. Of the electrolytes investigated so far, those formed with Ni(++) salts are the most unusual. It appears as if the transport number of Ni(2) and the electrolyte conductivity can be greatly enhanced by controlling the hydration and dehydration of the polymer.

  6. Free radical (co)polymerization of methyl methacrylate and styrene in room temperature ionic liquids

    Science.gov (United States)

    Zhang, Hongwei

    Conventional free radical polymerizations were carried out in a variety of room temperature ionic liquids (RTILs). Generally, methyl methacrylate (MMA) and styrene (St) were used as typical monomers to compare the polymerization behavior both in RTILs and in common volatile organic compound solvents (VOCs). In most cases, it was observed that both yields and molecular weights are enhanced in the RTIL. While we believe the "diffusion-controlled termination" mechanism makes the termination of the radical propagating chains difficult due to the highly viscous nature of RTIL, other researchers have suggested that the rapid polymerization rates are due to the high polarity of these reaction media. By employing more than a dozen RTILs with a wide range of anions and cations, we attempted to correlate the viscosity and polarity of the RTILs with the molecular weights and polymerization rates. This correlation was not successful, suggesting that other parameters may also play a role in affecting the polymerization behavior. Other kinds of polymerizations have also been attempted including nitroxide-mediated living radical polymerizations of St and MMA in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6), and redox initiation system initiated polymerization of MMA through redox pair formed by cation of trihexyl-tetradecyl-phosphonium bis(2,4,4-trimethylpentyl) phosphinate ([H3TDP] [(PM3) 2P]) and BPO. The formation of PSt-b-PMMA by sequential monomer addition through the standard free radical polymerization mechanism, using BPO as initiator, can be realized in [BMIM]PF6 due to the insolubility of polymerized first block---PSt in [BMIM]PF6. The macroradicals wrapped inside the chain coils have prolonged lifetimes because of the diminished termination, which allow some of these radicals to initiate polymerization of MMA at room temperature to form diblock copolymer. Solvents effects on reactivity ratios for free radical statistical copolymerization have been

  7. Determination and Temperature Dependence of Plateau Modulus for Polymerization of Propylene to Isotactic Polypropylene with Ultra-high Molecular Weight under Catalysis of Ziegler-Natta Catalyst

    Institute of Scientific and Technical Information of China (English)

    DING Jian; DING Xue-jia; XU Ri-wei; YU Ding-sheng

    2005-01-01

    The viscoelastic behavior of isotactic polypropylene with ultra-high molecular weight (UHPPH) and broad molecular weight distribution(MWD), produced in the presence of Ziegler-Natta catalyst, was investigated by means of oscillatory rheometry at 180 and 200 ℃, whose loss modulus(G") plots at 180 and 200 ℃versus the natural logarithm of angular frequency(ω) present a pronounced maximum at 34.35 and 69.21 rad/s, respectively, and do not show a maximum peak at 0. 01-100 rad/s for Ziegler-Natta catalyzing ethylenepropylene random copolymerization (PPR) with a conventional molecular weight and broad MWD. The fact indicates that the high molecular weight is responsible for a maximum peak of G"(ω) vs. lnω curves for UHPPH. This makes it possible to determine the plateau modulus (G0N) of UHPPH from a certain experimental temperature G"(ω) curve directly. For UHPPH, the G0N determined to be 4. 28×105 and 3. 62×105 Pa at 180and 200 ℃, respectively, decreases with the increase of temperature and is independent of the molecular weight, which directly confirms reputation theoretical prediction that the G0N has no relation to the molecular weight.

  8. Solar thermal collectors in polymeric materials: A novel approach towards higher operating temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Joao Farinha; Horta, Pedro; Carvalho, Maria Joao [INETI - Inst. Nacional de Engenharia Tecnologia e Inovacao, IP, Lisboa (Portugal); Silva, Paulo [PLASDAN - Maquinas para Plasticos, Marinha Grande (Portugal)

    2008-07-01

    The increasing demand for low temperature solar thermal collectors, especially for hot water production purposes in dwellings, swimming pools, hotels or industry, has lead to the possibility of high scale production, with leading manufacturers presenting yearly productions of hundreds of thousands of square meters. In such conditions, the use of polymeric materials in the manufacturing of solar collectors acquires particular interest, opening a full scope of opportunities for lower production costs, by means of cheaper materials or simpler manufacturing operations. Yet, the use of low cost materials limits the maximum operating temperatures estimated for the collectors (stagnation) to values around 120 C, easily attainable by any simple glazed solar collector. Higher performances, leading to higher stagnation temperatures as those observed for regular metal-based solar thermal collectors, would require high temperature polymers, at a much higher cost. The present paper addresses the manufacturing of a high performance solar thermal collector based in polymeric materials and includes a base thermal study, highlighting the different possibilities to be followed in the production of a polymeric collector, as well as a description of different temperature control strategies. (orig.)

  9. Effect of composite resin polymerization modes on temperature rise in human dentin of different thicknesses: an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Baggio Aguiar, Flavio Henrique; Kanda Peres Barros, Gisele; Alves Nunes Leite Lima, Debora; Bovi Ambrosano, Glaucia Maria; Lovadino, Jose Roberto [Piracicaba School of Dentistry, Campinas State University, Av. Limeira, 901, SP (Brazil)

    2006-09-15

    The aim of this in vitro study was to evaluate the effect of different polymerization modes on temperature rise in human dentin of different thicknesses, and to evaluate the relation between dentin thickness and temperature rise (TR). For this purpose, 60 specimens were assigned into 20 groups (n = 3): five polymerization modes (1-conventional; 2-soft-start; 3-high intensity; 4-ramp cure: progressive and high intensity; 5-high intensity with the tip of the light-curing unit at a distance of 1.3 cm for 10 s and the tip leaning on the sample) at four dentin thicknesses (0, 1, 2, 3 mm). During composite sample polymerization (2 mm), the temperature was measured by a digital laser thermometer (CMSS2000-SL/SKF). The statistical analyses were conducted by ANOVA (p = 0.05) and post-hoc Tukey's test. There were statistical differences of TR among polymerization modes and dentin thicknesses. The temperature rise was dependent on the polymerization mode and the dentin thickness: the thicker the dentin and the lower the polymerization mode energy, the lower the temperature rise.

  10. Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

    Directory of Open Access Journals (Sweden)

    Hiep Dinh Nguyen

    2016-10-01

    Full Text Available A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA were polymerized using an immobilized Candida antarctica lipase B (CALB and the potential for an enzymatic synthesis of alkyds was investigated. The developed method enables the use of both glycerol and also pentaerythritol (for the first time as the alcohol source and was found to be very robust. This allows simple variations in the molar mass and structure of the polyester without premature gelation, thus enabling easy tailoring of the branched polyester structure. The postpolymerization crosslinking of the polyesters illustrates their potential as binders in alkyds. The formed films had good UV stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition.

  11. Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

    DEFF Research Database (Denmark)

    Nguyen, Hiep Dinh; Löf, David; Hvilsted, Søren

    2016-01-01

    A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA....... This allows simple variations in the molar mass and structure of the polyester without premature gelation, thus enabling easy tailoring of the branched polyester structure. The postpolymerization crosslinking of the polyesters illustrates their potential as binders in alkyds. The formed films had good UV...... stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition....

  12. Donor Acceptor Polymerization Chemistry as a Vehicle to Low Energy Cure of Matrix Resins: Evolution of the 2-Tg Concept to Produce High Tg Polymers at Ambient Temperatures

    Science.gov (United States)

    1989-03-01

    tetrafunctional acceptors. DSC and TGA analysis of these polymers indicated they possessed the thermal stability necessary for performance in their...be enhanced by choosing comonomers that act as "solvents", and that the "onset of decomposition" temperature as measured by TGA analysis under nitrogen

  13. High Temperature Materials Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The High Temperature Materials Lab provides the Navy and industry with affordable high temperature materials for advanced propulsion systems. Asset List: Arc Melter...

  14. Radiation-induced solid state polymerization of N-substituted acrylamides and methacrylamides at reduced temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zurakowska-Orszagh, J.; Gumulka, A.; Bartnik, J. (Warsaw Univ. (Poland). Dept. of Chemistry)

    1984-01-01

    Radiation-induced solid state in-source polymerization and post-polymerization at reduced temperature of a series of N-tert-alkylacrylamides and pairs of monomers of the acrylamide and methacrylamide series with identical aliphatic aromatic and alicyclic substituents has been studied. The effect of the changes in the structure of particular monomers on their reactivity at reduced temperature as compared with their reactivity at room temperature has been considered.

  15. Development and Evaluation of Anti Ultra-high Temperature and Salt Tolerant Polymeric Filtrate Loss Reducer%钻井液用超高温抗盐聚合物降滤失剂的研制与评价

    Institute of Scientific and Technical Information of China (English)

    黄维安; 邱正松; 曹杰; 钟汉毅; 张现斌; 张世锋

    2012-01-01

    Aimed at the outstanding problem of adjustment of filtration property and high temperature stability of high temperature water-based drilling fluid at home and abroad, the anti 240 ℃ and salt tolerant polymeric filtrate loss reducer HTP-1 was developed based on optimum design of molecular structure and selection Of monomer. The optimum Synthesis conditions of HTP-1 was as follows : pH value was 7.0, the mass ratio of DEAM, AMPS, NVP, DMDACC was 6 : 3 : 3 : 1, the initiator content was 0. 1%, reaction temperature was 60℃ and reaction time was 4 h. the result of thermal gravitational analysis showed that the thermal decomposition onset temperature of HTP-1 was up to 320℃, indicating that HTP-1 possessed strong thermal stability. The experiments of calcium and salt tolerance showed that performance of HTP-1 in drilling fluid containing 267 g/L salt or 5 g/L calcium chloride was stable, which was similar to that of the foreign anti high temperature polymer Driscal and superior to domestic metallic ion fluid loss additive PMHA- U. The filtration reducing ability of HTP-1 at high temperature of 240℃ was better than that of Driscal (240℃) and domestic PMHA- II (220℃) in fresh water drilling fluid, weighted fresh water drilling fluid, saturated brine drilling fluid and compound salt water drilling fluid, respectively. In the end, the mechanisms of heat and salinity tolerance and filtrate loss reduction of HTP-1 were probed.%针对当前国内外超高温水基钻井液高温稳定性及滤失性调控技术难题,基于分子结构优化设计、聚合单体优选,通过优化合成条件研制了抗高温(240%)抗盐聚合物降滤失剂HTP-1。HTP-1的最优合成条件为:pH=7.0、单体配比DEAM:AMPS:NVP:DMDACC=6:3:3:1、引发剂0.1%、反应温度60℃、反应时间4h。热重分析表明,HTP-1的热稳定性很强,发生热分解的初始温度达320℃以上。HTP-1的抗盐能力大于267g

  16. Heat treatment of medium-temperature Sasol-Lurgi gasifier coal-tar pitch for polymerizing to higher value products

    Energy Technology Data Exchange (ETDEWEB)

    K. Mokoena; T.J. Van der Walt; T.J. Morgan; A.A. Herod; R. Kandiyoti [Sasol Technology (Pty) Ltd., Sasolburg (South Africa). R& amp; D Division

    2008-05-15

    Two coal-derived pitch samples, one a medium temperature pitch from a Sasol-Lurgi gasifier and the other from a high temperature coking process, have been heat treated to induce polymerization, both separately and as a mixture of pitches (co-pyrolysis). The initial pitch samples and the heat-treated samples have been examined by size exclusion chromatography (SEC) in 1-methyl-2-pyrrolidinone (NMP), by UV-fluorescence spectroscopy (UV-F), by solid state {sup 13}C NMR; elemental analyses of the initial pitch samples have been carried out. The Sasol-Lurgi pitch showed larger apparent sizes, more alkyl and carbonyl functions, and smaller polycyclic aromatic hydrocarbon (PAH) groups than the high temperature pitch. Co-pyrolysis of the two pitches indicated that polymerized product from the Sasol-Lurgi pitch can be used as an extender for high-temperature binder pitch. 16 refs., 7 figs., 2 tabs.

  17. Advanced Polymeric Materials for High-tech Innovations

    Institute of Scientific and Technical Information of China (English)

    TANG; BenZhong

    2001-01-01

    High technology is advancing our society and modernizing our life and advanced materials play an important role in the technological innovations. My research group has been working on the development of advanced polymeric materials and in this talk I will report our recent work on the creation of new conjugated polymers with novel molecular structures and unique materials properties.1-18 Our work include the design of molecular structures of monomeric building blocks, development of stable, effective and environmentally benign "green” polymerization catalysts, discovery of new polymerization reactions, synthesis of functional macromolecules, fabrication of nanodimensional composites, assembly and control of hierarchical structures, and construction of electrooptical devices. We have revealed the liquid crystallinity, light emission, photoconductivity, optical limiting, nano-hybridization, solvatochromism, optical activity, self-organization, and biological activity of the linear polyacetylenes and hyperbranched polyarylenes. The utilization of the advanced polymers and their interesting materials properties for high-tech innovations will be discussed.  ……

  18. Advanced Polymeric Materials for High-tech Innovations

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ High technology is advancing our society and modernizing our life and advanced materials play an important role in the technological innovations. My research group has been working on the development of advanced polymeric materials and in this talk I will report our recent work on the creation of new conjugated polymers with novel molecular structures and unique materials properties.1-18 Our work include the design of molecular structures of monomeric building blocks, development of stable, effective and environmentally benign "green” polymerization catalysts, discovery of new polymerization reactions, synthesis of functional macromolecules, fabrication of nanodimensional composites, assembly and control of hierarchical structures, and construction of electrooptical devices. We have revealed the liquid crystallinity, light emission, photoconductivity, optical limiting, nano-hybridization, solvatochromism, optical activity, self-organization, and biological activity of the linear polyacetylenes and hyperbranched polyarylenes. The utilization of the advanced polymers and their interesting materials properties for high-tech innovations will be discussed.

  19. Colloidal and micro-carbon spheres derived from low-temperature polymerization reactions.

    Science.gov (United States)

    Moreno-Castilla, Carlos

    2016-10-01

    Carbon spheres (CSs) have recently attracted major interest due to their new applications, mainly in energy storage and conversion but also in hard-templating, sorption/catalysis processes, and drug delivery systems. This is attributable to their physico-chemical properties, including their tunable morphology (solid, hollow and core-shell), size, surface area/porosity, good electrical conductivity, low external surface-to-volume ratio, high packing density, enhanced mass transport, robust mechanical stability, low cytotoxicity, and excellent biocompatibility. They can be obtained from a wide variety of carbon precursors and methods. This review covers their production by carbonization of polymer spheres from low-temperature polymerization reactions, considered here as below 250°C. This is a very important method because it allows the synthesis of CSs with different morphologies and doped with other elements or chemical compounds. The preparation of polymer spheres by this technique is well documented in the literature, and the objective of this review is to summarize and give an overview of the most significant publications, proposing a novel classification based on the formation mechanism of the polymer spheres. This classification includes the following polymerization processes: emulsion polymerization and its derivatives, seeded emulsion and inverse emulsion polymerization; precipitation polymerization and its derivative, dispersion polymerization; hard-templating; spray-drying; and hydrothermal or solvothermal treatment of carbohydrates and biomass in general. This review also reports on the morphology and surface characteristics of the CSs obtained by different synthetic approaches. The final section of the review describes the current applications of these CSs, notably in energy storage (supercapacitors and rechargeable batteries) and energy conversion (fuel cells and dye-sensitized solar cells). Besides the numerous applications listed above, they are

  20. Space charge accumulation in polymeric high voltage DC cable systems

    NARCIS (Netherlands)

    Bodega, R.

    2006-01-01

    One of the intrinsic properties of the polymeric high voltage (HV) direct current (DC) cable insulation is the accumulation of electrostatic charges. Accumulated charges distort the initial Laplacian distribution of the electric field, leading to a local field enhancement that may cause insulation d

  1. A cell-permeable fluorescent polymeric thermometer for intracellular temperature mapping in mammalian cell lines.

    Directory of Open Access Journals (Sweden)

    Teruyuki Hayashi

    Full Text Available Changes in intracellular temperatures reflect the activity of the cell. Thus, the tool to measure intracellular temperatures could provide valuable information about cellular status. We previously reported a method to analyze the intracellular temperature distribution using a fluorescent polymeric thermometer (FPT in combination with fluorescence lifetime imaging microscopy (FLIM. Intracellular delivery of the FPT used in the previous study required microinjection. We now report a novel FPT that is cell permeable and highly photostable, and we describe the application of this FPT to the imaging of intracellular temperature distributions in various types of mammalian cell lines. This cell-permeable FPT displayed a temperature resolution of 0.05°C to 0.54°C within the range from 28°C to 38°C in HeLa cell extracts. Using our optimized protocol, this cell-permeable FPT spontaneously diffused into HeLa cells within 10 min of incubation and exhibited minimal toxicity over several hours of observation. FLIM analysis confirmed a temperature difference between the nucleus and the cytoplasm and heat production near the mitochondria, which were also detected previously using the microinjected FPT. We also showed that this cell-permeable FPT protocol can be applied to other mammalian cell lines, COS7 and NIH/3T3 cells. Thus, this cell-permeable FPT represents a promising tool to study cellular states and functions with respect to temperature.

  2. A cell-permeable fluorescent polymeric thermometer for intracellular temperature mapping in mammalian cell lines.

    Science.gov (United States)

    Hayashi, Teruyuki; Fukuda, Nanaho; Uchiyama, Seiichi; Inada, Noriko

    2015-01-01

    Changes in intracellular temperatures reflect the activity of the cell. Thus, the tool to measure intracellular temperatures could provide valuable information about cellular status. We previously reported a method to analyze the intracellular temperature distribution using a fluorescent polymeric thermometer (FPT) in combination with fluorescence lifetime imaging microscopy (FLIM). Intracellular delivery of the FPT used in the previous study required microinjection. We now report a novel FPT that is cell permeable and highly photostable, and we describe the application of this FPT to the imaging of intracellular temperature distributions in various types of mammalian cell lines. This cell-permeable FPT displayed a temperature resolution of 0.05°C to 0.54°C within the range from 28°C to 38°C in HeLa cell extracts. Using our optimized protocol, this cell-permeable FPT spontaneously diffused into HeLa cells within 10 min of incubation and exhibited minimal toxicity over several hours of observation. FLIM analysis confirmed a temperature difference between the nucleus and the cytoplasm and heat production near the mitochondria, which were also detected previously using the microinjected FPT. We also showed that this cell-permeable FPT protocol can be applied to other mammalian cell lines, COS7 and NIH/3T3 cells. Thus, this cell-permeable FPT represents a promising tool to study cellular states and functions with respect to temperature.

  3. Gold-Loaded Polymeric Micelles with Temperature-Modulated Catalytic Activity

    Institute of Scientific and Technical Information of China (English)

    HU Na; SHI Dongjian; LI Jihang; LI Junfeng; CHEN Mingqing

    2015-01-01

    Four-armed amphiphilic block copolymers, polystyrene-b-poly(N-isopropylacrylamide) (PS-b-PNIPAM)4, were synthesized by atom transfer radical polymerization (ATRP). (PS-b-PNIPAM)4 self-assembled into micelles with PS block as core and thermoresponsive PNIPAM block as corona. The gold nanoparticles (Au NPs) with average diameter about 5.8 nm were immobilized on the surfaces of the micelles by the reduction of the corresponding ions. The micelle-supported gold nanoparticles (Au-micelles) were applied to catalyze the reduction ofp-nitrophenol. Moreover, the activity of the Au-micelle catalyst could be modulated by the temperature and the Au-micelles could be easily recovered by changing the temperature and recycled four times with high catalytic activity.

  4. Bitumen modifiers for reduced temperature asphalts: a comparative analysis between three polymeric and non-polymeric additives

    OpenAIRE

    Cuadri Vega, Antonio Abad; Carrera Páez, Virginia; Izquierdo Rodríguez, María Angeles; García Morales, Moisés; Navarro Domínguez, Francisco Javier

    2014-01-01

    This study presents three bitumen modifiers which may find successful application in the fabrication of binders for warm mix asphalt in the paving industry. In that sense, two non-polymeric additives, thiourea and thiourea dioxide, along with a reactive isocyanate-terminated prepolymer have been evaluated. Viscous flow and linear viscoelasticity tests, at 60 ºC, reveal bituminous modified binders which evolve towards highly viscous materials when subjected to ambient curing. However, at 135 º...

  5. Bitumen modifiers for reduced temperature asphalts: a comparative analysis between three polymeric and non-polymeric additives

    OpenAIRE

    Cuadri Vega, Antonio Abad; Carrera Páez, Virginia; Izquierdo Rodríguez, María Angeles; García Morales, Moisés; Navarro Domínguez, Francisco Javier

    2014-01-01

    This study presents three bitumen modifiers which may find successful application in the fabrication of binders for warm mix asphalt in the paving industry. In that sense, two non-polymeric additives, thiourea and thiourea dioxide, along with a reactive isocyanate-terminated prepolymer have been evaluated. Viscous flow and linear viscoelasticity tests, at 60 ºC, reveal bituminous modified binders which evolve towards highly viscous materials when subjected to ambient curing. However, at 135 º...

  6. HIGH TEMPERATURE DISPLACEMENT SENSOR

    Institute of Scientific and Technical Information of China (English)

    Xu Longxiang; Zhang Jinyu; Schweitzer Gerhard

    2005-01-01

    A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90~350 mV at 550℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2~3 V at 550℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550℃ in a magnetic bearing system for more than 100 h.

  7. High-Temperature Superconductivity

    Science.gov (United States)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  8. Surface-initiated atom transfer radical polymerization of methyl methacrylate from magnetite nanoparticles at ambient temperature.

    Science.gov (United States)

    Raghuraman, G K; Dhamodharan, R

    2006-07-01

    The synthesis of methyl methacrylate (MMA) brush from the surface of magnetite nanoparticles (core-shell structure), from initiator moieties anchored covalently to the nanoparticles, via room temperature atom transfer radical polymerization (ATRP) is described. The surface-initiated polymerization was carried out from a surface-confined initiator containing a 2-bromoisobutyrate moiety with Cu(I)Br/PMDETA catalytic system. The initiator moiety was covalently anchored to the nanoparticles via a two step modification reaction scheme. Controlled polymerization was observed if ethyl-2-bromoisobutyrate (2-EiBrB) was added as a free/sacrificial initiator. A linear increase of molecular weight and a narrow molecular weight distribution of the PMMA formed in solution, provide evidence for a controlled surface-initiated polymerization, leading to surface-attached polymer brushes under mild conditions. The grafted PMMA provides good stability and dispersibility for the nanoparticles in organic solvents.

  9. High temperature catalytic membrane reactors

    Energy Technology Data Exchange (ETDEWEB)

    1990-03-01

    Current state-of-the-art inorganic oxide membranes offer the potential of being modified to yield catalytic properties. The resulting modules may be configured to simultaneously induce catalytic reactions with product concentration and separation in a single processing step. Processes utilizing such catalytically active membrane reactors have the potential for dramatically increasing yield reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity. Examples of commercial interest include hydrogenation, dehydrogenation, partial and selective oxidation, hydrations, hydrocarbon cracking, olefin metathesis, hydroformylation, and olefin polymerization. A large portion of the most significant reactions fall into the category of high temperature, gas phase chemical and petrochemical processes. Microporous oxide membranes are well suited for these applications. A program is proposed to investigate selected model reactions of commercial interest (i.e. dehydrogenation of ethylbenzene to styrene and dehydrogenation of butane to butadiene) using a high temperature catalytic membrane reactor. Membranes will be developed, reaction dynamics characterized, and production processes developed, culminating in laboratory-scale demonstration of technical and economic feasibility. As a result, the anticipated increased yield per reactor pass economic incentives are envisioned. First, a large decrease in the temperature required to obtain high yield should be possible because of the reduced driving force requirement. Significantly higher conversion per pass implies a reduced recycle ratio, as well as reduced reactor size. Both factors result in reduced capital costs, as well as savings in cost of reactants and energy.

  10. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard;

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...

  11. Highly stereospecific polymerization of isoprene with homogeneous binary Ziegler-Natta catalysts based on NCN-pincer neodymium precursor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The aryldiimine NCN-pincer stabilized neodymium dichloride combined with aluminum alkyls established a new type of homogeneous binary neutral Ziegler-Natta catalyst system.This system exhibited high activity and high cis-1,4 selectivity for the polymerization of isoprene (Tp=20 °C,98.2%;Tp=-20 °C,> 99%).Such catalytic performances remained under a broad range of polymerization temperatures and monomer-to-neodymium ratios (from 500 to 8000),reaching high number-average molecular weight (Mn=1582 kg/mol) and relatively narrow molecular weight distribution (PDI=1.68),which was,however,influenced by the amount and bulkiness of aluminum alkyls.Dynamic investigation of the polymerization was performed,which showed the number-average molecular weight of the resultant polyisoprene had an almost linear correlation with the conversion,suggesting,in some degree,the polymerization with this catalytic system was controllable.

  12. Polymeric Binders which Reversibly Dissociate at Elevated Temperatures

    Science.gov (United States)

    1978-05-01

    materials must be used which are capable of regenerating the free isocyana.e on heating and will not undergo undesirable side reactions . The most widely...such as imidazole, indazole and benzotriazole, exhibit a marked tendency to dissociate at temperatures as low as 80*C to 100*C. With 4,5...only undergo a Diels-Alder reaction at room temperature with a variety of dienes, but it will also react with other functional groups. Many of these

  13. High temperature battery. Hochtemperaturbatterie

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, M.

    1992-06-04

    To prevent heat losses of a high temperature battery, it is proposed to make the incoming current leads in the area of their penetration through the double-walled insulating housing as thermal throttle, particularly spiral ones.

  14. Oxidation and low temperature stability of polymerized soybean oil-based lubricants

    Science.gov (United States)

    Oxidation and low temperature stability of polymerized soybean oil (PSO)-based lubricants have been investigated by the pressurized differential scanning calorimetry (PDSC) method. It was found that PSO samples have lower oxidative stability than their precursor, soybean oil. The main reason for the...

  15. High Temperature Capacitor Development

    Energy Technology Data Exchange (ETDEWEB)

    John Kosek

    2009-06-30

    The absence of high-temperature electronics is an obstacle to the development of untapped energy resources (deep oil, gas and geothermal). US natural gas consumption is projected to grow from 22 trillion cubic feet per year (tcf) in 1999 to 34 tcf in 2020. Cumulatively this is 607 tcf of consumption by 2020, while recoverable reserves using current technology are 177 tcf. A significant portion of this shortfall may be met by tapping deep gas reservoirs. Tapping these reservoirs represents a significant technical challenge. At these depths, temperatures and pressures are very high and may require penetrating very hard rock. Logistics of supporting 6.1 km (20,000 ft) drill strings and the drilling processes are complex and expensive. At these depths up to 50% of the total drilling cost may be in the last 10% of the well depth. Thus, as wells go deeper it is increasingly important that drillers are able to monitor conditions down-hole such as temperature, pressure, heading, etc. Commercial off-the-shelf electronics are not specified to meet these operating conditions. This is due to problems associated with all aspects of the electronics including the resistors and capacitors. With respect to capacitors, increasing temperature often significantly changes capacitance because of the strong temperature dependence of the dielectric constant. Higher temperatures also affect the equivalent series resistance (ESR). High-temperature capacitors usually have low capacitance values because of these dielectric effects and because packages are kept small to prevent mechanical breakage caused by thermal stresses. Electrolytic capacitors do not operate at temperatures above 150oC due to dielectric breakdown. The development of high-temperature capacitors to be used in a high-pressure high-temperature (HPHT) drilling environment was investigated. These capacitors were based on a previously developed high-voltage hybridized capacitor developed at Giner, Inc. in conjunction with a

  16. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

    The present book aims at describing the phenomenon of superconductivity and high-temperature superconductors discovered by Bednorz and Muller in 1986. The book covers the superconductivity phenomenon, structure of high-Tc superconductors, critical currents, synthesis routes for high Tc materials, superconductivity in cuprates, the proximity effect and SQUIDs, theories of superconductivity and applications of superconductors.

  17. High Temperature ESP Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jack Booker; Brindesh Dhruva

    2011-06-20

    The objective of the High Temperature ESP Monitoring project was to develop a downhole monitoring system to be used in wells with bottom hole well temperatures up to 300°C for measuring motor temperature, formation pressure, and formation temperature. These measurements are used to monitor the health of the ESP motor, to track the downhole operating conditions, and to optimize the pump operation. A 220 ºC based High Temperature ESP Monitoring system was commercially released for sale with Schlumberger ESP motors April of 2011 and a 250 ºC system with will be commercially released at the end of Q2 2011. The measurement system is now fully qualified, except for the sensor, at 300 °C.

  18. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also...... input to the cell then hydrogen is produced giving syngas. This syngas can then be further reacted to form hydrocarbon fuels and chemicals. Operating at high temperature gives much higher efficiencies than can be achieved with low temperature electrolysis. Current state of the art SOECs utilise a dense...

  19. STUDIES ON HIGH SOLID CONTENT AND STABLE EMULSIFIER—FREE EMULSION POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    TangGuangliang; HaoGuangjie; 等

    1998-01-01

    In this article,AHPS(3-allyloxy-2-hydroxy-1-propanesulfonate salt) was synthesized to use in emulsifier-free emulsion polymerization of BA/BMA/MMA system for high solid content latexes.Storage stability,flow behavior of the latexes,morphology of the obtained latex particles,dynamic viscoelastic behavior,tensile strength and water resistance properties of the resulted copolymers were investigated.The experimental results show that with the addition of AHPS,stability of the emulsion is greatly improved that there appears no apparent precipitation during the polymerization and storage at room temperature for 6 months and at -10℃ for four months.Flow of the latexes follows the Bingham body laws,diameter of the latex particles is about 0.6μm,of which is larger than that of by conventional emulsion polymerization(0.12μm).In addition,not only water resistance of the copolymers obtained by emulsifier-free emulstion polymerization is greatly improved,but also tensile strength is obviously enhanced.

  20. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  1. Importance of salt and temperature in myosin polymerization during surimi gelation.

    Science.gov (United States)

    Núñez-Flores, Ruth; Cando, Deysi; Borderías, A Javier; Moreno, Helena M

    2018-01-15

    To address the effect of absence of NaCl on myosin heavy chain polymerization during two-step surimi gelation (different setting temperatures/times -5°C/24h and 30°C/30min-followed by heating at 90°C/30min) were considered. In gel samples made without salt (Lot A), no myosin heavy chain (MHC) polymerization was observed, only aggregation, as indicated by the electrophoresis in polyacrylamide/agarose gel profile. Moreover, these gels were characterized by weakly stabilized protein networks as denoted by the dynamic oscillatory measurement and FTIR analysis, resulting in poor quality gels. On the other hand, in gels made with added salt, MHC polymerization occurred, as evidenced by the electrophoresis, and the gelation resulted in a well-stabilized protein network with good physicochemical properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Intracellular temperature mapping with a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy.

    Science.gov (United States)

    Okabe, Kohki; Inada, Noriko; Gota, Chie; Harada, Yoshie; Funatsu, Takashi; Uchiyama, Seiichi

    2012-02-28

    Cellular functions are fundamentally regulated by intracellular temperature, which influences biochemical reactions inside a cell. Despite the important contributions to biological and medical applications that it would offer, intracellular temperature mapping has not been achieved. Here we demonstrate the first intracellular temperature mapping based on a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy. The spatial and temperature resolutions of our thermometry were at the diffraction limited level (200 nm) and 0.18-0.58 °C. The intracellular temperature distribution we observed indicated that the nucleus and centrosome of a COS7 cell, both showed a significantly higher temperature than the cytoplasm and that the temperature gap between the nucleus and the cytoplasm differed depending on the cell cycle. The heat production from mitochondria was also observed as a proximal local temperature increase. These results showed that our new intracellular thermometry could determine an intrinsic relationship between the temperature and organelle function.

  3. Strangeness at high temperatures

    CERN Document Server

    Schmidt, Christian

    2013-01-01

    We use up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number fluctuations to extract information on the strange meson and baryon contribution to the low temperature hadron resonance gas, the dissolution of strange hadronic states in the crossover region of the QCD transition and the quasi-particle nature of strange quark contributions to the high temperature quark-gluon plasma phase.

  4. Method for independent strain and temperature measurement in polymeric tensile test specimen using embedded FBG sensors

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; McGugan, Malcolm; Mikkelsen, Lars Pilgaard

    2016-01-01

    A novel method to obtain independent strain and temperature measurements using embedded Fibre Bragg Grating (FBG) in polymeric tensile test specimens is presented in this paper. The FBG strain and temperature cross-sensitivity was decoupled using two single mode FBG sensors, which were embedded...... in the specimen material with a certain angle between them. It is demonstrated that, during temperature variation, both FBG sensors show the same signal response. However, for any applied load the signal response is different, which is caused by the different levels of strain acting in each sensor. Equations...... calibration procedure (temperature and strain) was performed to this material-sensor pair, where a calibration error

  5. High-order WENO scheme for polymerization-type equations*

    Directory of Open Access Journals (Sweden)

    Gabriel Pierre

    2010-12-01

    Full Text Available Polymerization of proteins is a biochemical process involved in different diseases. Mathematically, it is generally modeled by aggregation-fragmentation-type equations. In this paper we consider a general polymerization model and propose a high-order numerical scheme to investigate the behavior of the solution. An important property of the equation is the mass conservation. The WENO scheme is built to preserve the total mass of proteins along time. Le processus biophysique de polymérisation de protéines entre en jeu dans différentes maladies. Mathématiquement, ceci est généralement modélisé par des équations de type agrégation-fragmentation. Dans cet article nous considérons un modèle général de polymérisation et proposons un schéma d’ordre élevé pour sa résolution numérique. Une propriété importante de l’équation est la conservation de la masse. Le schéma WENO est construit pour conserver la masse totale de protéines au cours du temps.

  6. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  7. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  8. Desulfurization at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Panula-Nikkilae, E.; Kurkela, E.; Mojtahedi, W.

    1987-01-01

    Two high-temperature desulfurization methods, furnace injection and gasification-desulfurization are presented. In furnace injection, the efficiency of desulfurization is 50-60%, but this method is applied in energy production plants, where flue gas desulfurization cannot be used. Ca-based sorbents are used as desulfurization material. Factors affecting desulfurization and the effect of injection on the boiler and ash handling are discussed. In energy production based on gasification, very low sulfur emissions can be achieved by conventional low-temperature cleanup. However, high-temperature gas cleaning leads to higher efficiency and can be applied to smaller size classes. Ca-, Fe-, or Zn-based sorbents or mixed metals can be used for desulfurization. Most of the methods under development are based on the use of regenerative sorbents in a cleanup reactor located outside the gasifier. So far, only calcium compounds have been used for desulfurization inside the gasifier.

  9. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  10. Effect of the polymerization with formaldehyde on the thermal reactivity of a low-temperature coal tar pitch

    Energy Technology Data Exchange (ETDEWEB)

    Jose L. Crespo; Ana Arenillas; Jose A. Vin; Roberto Garcia; Colin E. Snape; Sabino R. Moinelo [Instituto Nacional del Carbon (CSIC), Oviedo (Spain)

    2005-04-01

    The influence of polymerization with formaldehyde on the thermal reactivity of a low-temperature coal tar pitch has been investigated. The mechanism and extent of the polymerization depends on the catalyst used, the greatest extent of polymerization being achieved under basic catalytic conditions. After the polymerization treatment, samples were carbonized at 420{sup o}C and the products were characterized by optical microscopy. According to the results, polymerization with formaldehyde increases the reactivity of the pitch, giving rise to increased carbonization yields and leading to the formation of the mesophase with milder conditions. The polymerization process also affects the morphology of the resultant anisotropic material, giving rise to the formation of irregularly shaped mesophase particles and reducing the optical texture size of the anisotropic domains, giving mosaic texture, especially when basic catalysis is used. 36 refs., 11 figs., 5 tabs.

  11. Low toxicity high temperature PMR polyimide

    Science.gov (United States)

    Pater, Ruth H. (Inventor)

    1992-01-01

    In-situ polymerization of monomer reactants (PMR) type polyimides constitute an important class of ultra high performance composite matrix resins. PMR-15 is the best known and most widely used PMR polyimide. An object of the present invention is to provide a substantially improved high temperature PMR-15 system that exhibits better processability, toughness, and thermo-oxidative stability than PMR-15, as well as having a low toxicity. Another object is to provide new PMR polyimides that are useful as adhesives, moldings, and composite matrices. By the present invention, a new PMR polyimide comprises a mixture of the following compounds: 3,4'-oxydianiline (3,4'-ODA), NE, and BTDE which are then treated with heat. This PMR was designated LaRC-RP46 and has a broader processing window, better reproducibility of high quality composite parts, better elevated temperature mechanical properties, and higher retention of mechanical properties at an elevated temperature, particularly, at 371 C.

  12. Fast and Living Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides Triggered by an "Alliance" of Primary and Secondary Amines at Room Temperature

    KAUST Repository

    Zhao, Wei

    2015-04-13

    A novel highly efficient strategy, based on an "alliance" of primary and secondary amine initiators, was successfully developed allowing the fast and living ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCAs) at room temperature. (Chemical Equation Presented). © 2015 American Chemical Society.

  13. Crystal structure of polymeric carbon nitride and the determination of its process-temperature-induced modifications

    Science.gov (United States)

    Tyborski, T.; Merschjann, C.; Orthmann, S.; Yang, F.; Lux-Steiner, M.-Ch; Schedel-Niedrig, Th

    2013-10-01

    Based on the arrangement of two-dimensional ‘melon’, we construct a unit cell for polymeric carbon nitride (PCN) synthesized via thermal polycondensation, whose theoretical diffraction powder pattern includes all major features measured in x-ray diffraction. With the help of this unit cell, we describe the process-temperature-induced crystallographic changes in PCN that occur within a temperature interval between 510 and 610 °C. We also discuss further potential modifications of the unit cell for PCN. It is found that both triazine- and heptazine-based g-C3N4 can only account for minor phases within the investigated synthesis products.

  14. High temperature superconducting compounds

    Science.gov (United States)

    Goldman, Allen M.

    1992-11-01

    The major accomplishment of this grant has been to develop techniques for the in situ preparation of high-Tc superconducting films involving the use of ozone-assisted molecular beam epitaxy. The techniques are generalizable to the growth of trilayer and multilayer structures. Films of both the DyBa2Cu3O(7-x) and YBa2Cu3O(7-x) compounds as well as the La(2-x)Sr(x)CuO4 compound have been grown on the usual substrates, SrTiO3, YSZ, MgO, and LaAlO3, as well as on Si substrates without any buffer layer. A bolometer has been fabricated on a thermally isolated SiN substrate coated with YSZ, an effort carried out in collaboration with Honeywell Inc. The deposition process facilitates the fabrication of very thin and transparent films creating new opportunities for the study of superconductor-insulator transitions and the investigation of photo-doping with carriers of high temperature superconductors. In addition to a thin film technology, a patterning technology has been developed. Trilayer structures have been developed for FET devices and tunneling junctions. Other work includes the measurement of the magnetic properties of bulk single crystal high temperature superconductors, and in collaboration with Argonne National Laboratory, measurement of electric transport properties of T1-based high-Tc films.

  15. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  16. High temperature materials and mechanisms

    CERN Document Server

    2014-01-01

    The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...

  17. Temperature rise during polymerization of different cavity liners and composite resins

    Directory of Open Access Journals (Sweden)

    Ozcan Karatas

    2015-01-01

    Full Text Available Objective: The purpose of this study was to evaluate the thermal insulating properties of different light curing cavity liners and composite resins during light emitting diode (LED curing. Materials and Methods: Sixty-four dentin discs, 1 mm thick and 8 mm in diameter, were prepared. Specimens were divided into four groups. Calcium hydroxide (Ca[OH] 2 , resin-modified glass ionomer cement, flowable composite and adhesive systems were applied to dentin discs according to the manufacturers′ instructions. The rise in temperature during polymerization with a LED curing unit (LCU was measured using a K-type thermocouple connected to a data logger. Subsequently, all specimens were randomly divided into one of two groups. A silorane-based composite resin and a methacrylate-based composite resin were applied to the specimens. Temperature rise during polymerization of composite resins with LCU were then measured again. Data were analyzed using one-way ANOVA and post hoc Tukey analyses. Results: There were significant differences in temperature rise among the liners, adhesives, and composite resins (P < 0.05. Silorane-based composite resin exhibited significantly greater temperature rises than methacrylate-based resin (P < 0.05. The smallest temperature rises were observed in Ca(OH 2 specimens. Conclusion: Thermal insulating properties of different restorative materials are important factors in pulp health. Bonding agents alone are not sufficient to protect pulp from thermal stimuli throughout curing.

  18. Effect of carbon-black treatment by radiation emulsion polymerization on temperature dependence of resistivity of carbon-black-filled polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Jia Shaojin [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China) and Department of Chemical Engineering, Shanghai University, Chengzhong Road 20, Shanghai 201800 (China)]. E-mail: jiashaojin2@yahoo.com.cn; Jiang Pingkai [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Zhang Zhicheng [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang Zhongguang [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China)

    2006-04-15

    High dispersibility and stability of carbon black particles in low-density-polyethylene (LDPE) matrix were obtained by radiation emulsion polymerization on carbon particles surface, and electrical resistivities of its simple were examined. First carbon particles treatment on radiation emulsion polymerization on surface were synthesized by the reaction with a polymer-emulsion systems containing reactive group in the molecular unit, carbon particles and emulsifier. Then, the carbon particles treatment on radiation emulsion polymerization on surface was dispersed into LDPE, and its composites were prepared for electrical measurements. The effect of radiation crosslinking of the composite on the Positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomenon was investigated. The experimental results showed that PTC and NTC effects of the composites were obviously influenced by the irradiation dose. Various microstructure-exploring means were used to study the conductive composite, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM)

  19. Effect of carbon-black treatment by radiation emulsion polymerization on temperature dependence of resistivity of carbon-black-filled polymer blends

    Science.gov (United States)

    Shaojin, Jia; Pingkai, Jiang; Zhicheng, Zhang; Zhongguang, Wang

    2006-04-01

    High dispersibility and stability of carbon black particles in low-density-polyethylene (LDPE) matrix were obtained by radiation emulsion polymerization on carbon particles surface, and electrical resistivities of its simple were examined. First carbon particles treatment on radiation emulsion polymerization on surface were synthesized by the reaction with a polymer-emulsion systems containing reactive group in the molecular unit, carbon particles and emulsifier. Then, the carbon particles treatment on radiation emulsion polymerization on surface was dispersed into LDPE, and its composites were prepared for electrical measurements. The effect of radiation crosslinking of the composite on the Positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomenon was investigated. The experimental results showed that PTC and NTC effects of the composites were obviously influenced by the irradiation dose. Various microstructure-exploring means were used to study the conductive composite, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM).

  20. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  1. Highly reflective polymeric substrates functionalized utilizing atomic layer deposition

    Science.gov (United States)

    Zuzuarregui, Ana; Coto, Borja; Rodríguez, Jorge; Gregorczyk, Keith E.; Ruiz de Gopegui, Unai; Barriga, Javier; Knez, Mato

    2015-08-01

    Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur.

  2. Highly reflective polymeric substrates functionalized utilizing atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zuzuarregui, Ana, E-mail: a.zuzuarregui@nanogune.eu; Gregorczyk, Keith E. [CIC Nanogune Consolider, de Tolosa Hiribidea 76, 20018 San Sebastián (Spain); Coto, Borja; Ruiz de Gopegui, Unai; Barriga, Javier [IK4-Tekniker, Iñaki Goenaga 5, 20600 Eibar (Spain); Rodríguez, Jorge [Torresol Energy (SENER Group), Avda. de Zugazarte 61, 48930 Las Arenas (Spain); Knez, Mato [CIC Nanogune Consolider, de Tolosa Hiribidea 76, 20018 San Sebastián (Spain); IKERBASQUE Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao (Spain)

    2015-08-10

    Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur.

  3. Thermodynamic prediction of glycine polymerization as a function of temperature and pH consistent with experimentally obtained results.

    Science.gov (United States)

    Kitadai, Norio

    2014-04-01

    Prediction of the thermodynamic behaviors of biomolecules at high temperature and pressure is fundamental to understanding the role of hydrothermal systems in the origin and evolution of life on the primitive Earth. However, available thermodynamic dataset for amino acids, essential components for life, cannot represent experimentally observed polymerization behaviors of amino acids accurately under hydrothermal conditions. This report presents the thermodynamic data and the revised HKF parameters for the simplest amino acid "Gly" and its polymers (GlyGly, GlyGlyGly and DKP) based on experimental thermodynamic data from the literature. Values for the ionization states of Gly (Gly(+) and Gly(-)) and Gly peptides (GlyGly(+), GlyGly(-), GlyGlyGly(+), and GlyGlyGly(-)) were also retrieved from reported experimental data by combining group additivity algorithms. The obtained dataset enables prediction of the polymerization behavior of Gly as a function of temperature and pH, consistent with experimentally obtained results in the literature. The revised thermodynamic data for zwitterionic Gly, GlyGly, and DKP were also used to estimate the energetics of amino acid polymerization into proteins. Results show that the Gibbs energy necessary to synthesize a mole of peptide bond is more than 10 kJ mol(-1) less than previously estimated over widely various temperatures (e.g., 28.3 kJ mol(-1) → 17.1 kJ mol(-1) at 25 °C and 1 bar). Protein synthesis under abiotic conditions might therefore be more feasible than earlier studies have shown.

  4. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  5. High temperature interface superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gozar, A., E-mail: adrian.gozar@yale.edu [Yale University, New Haven, CT 06511 (United States); Bozovic, I. [Yale University, New Haven, CT 06511 (United States); Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-02-15

    Highlight: • This review article covers the topic of high temperature interface superconductivity. • New materials and techniques used for achieving interface superconductivity are discussed. • We emphasize the role played by the differences in structure and electronic properties at the interface with respect to the bulk of the constituents. - Abstract: High-T{sub c} superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-T{sub c} Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  6. Highly electrophilic organometallics for carbocationic polymerizations: from anion engineering to new polymer materials.

    Science.gov (United States)

    Bochmann, Manfred

    2010-09-21

    Ion-ion interactions are a crucial but often overlooked aspect of many polymerization reactions. The precise nature of cation-anion binding is as yet poorly understood, and little is known of the extent of ionic interactions in the typically nonaqueous, low-polarity reaction media of most polymerizations. Nevertheless, adequate control of cation-anion interactions can greatly enhance the productivity and efficiency of chemical processes and can provide low-energy alternatives to current methods. This is illustrated here with the carbocationic polymerization of isoalkenes. Carbocationic polymerizations involve, as the name implies, carbocations as propagating species. Of the various types of substrates that can be polymerized cationically, the copolymerization of isobutene to isobutene-isoprene rubber stands out as the only large-scale, industrially important implementation of this reaction type. The products, elastomers with controlled degrees of unsaturation for subsequent cross-linking, have excellent gas barrier and mechanical dampening properties that make them indispensable components in polymer composites. For such applications, the polymer molecular weight has to be high, ∼5 × 10(5) g/mol, with 1-2 mol % isoprene. Cationic polymerizations are however notoriously difficult to control. As a means of suppressing chain transfer, the process is carried out at temperatures as low as -100 °C, with aluminum chloride initiators in chloromethane. Current industrial production of isobutene-isoprene butyl rubber is thus highly energy intensive and produces aluminum and chloride effluent. This Account summarizes how highly electrophilic organometallics coupled with new types of very weakly coordinating counteranions can provide the basis for a more environmentally friendly, lower energy alternative. Because any copolymerization of two monomers, here primarily isobutene and isoprene, leads to two different propagating species, each of which is characterized by

  7. High temperature interfacial superconductivity

    Science.gov (United States)

    Bozovic, Ivan [Mount Sinai, NY; Logvenov, Gennady [Port Jefferson Station, NY; Gozar, Adrian Mihai [Port Jefferson, NY

    2012-06-19

    High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator (La.sub.2CuO.sub.4) and a metal (La.sub.1-xSr.sub.xCuO.sub.4), neither of which is superconducting per se, is described. Depending upon the layering sequence of the bilayers, T.sub.c may be either .about.15 K or .about.30 K. This highly robust phenomenon is confined to within 2-3 nm around the interface. After exposing the bilayer to ozone, T.sub.c exceeds 50 K and this enhanced superconductivity is also shown to originate from a 1 to 2 unit cell thick interfacial layer. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T.sub.c phases and to significantly enhance superconducting properties in other superconductors. The superconducting interface may be implemented, for example, in SIS tunnel junctions or a SuFET.

  8. Photocatalyst-Free and Blue Light-Induced RAFT Polymerization of Vinyl Acetate at Ambient Temperature.

    Science.gov (United States)

    Ding, Chunlai; Fan, Caiwei; Jiang, Ganquan; Pan, Xiangqiang; Zhang, Zhengbiao; Zhu, Jian; Zhu, Xiulin

    2015-12-01

    Vinyl acetate is polymerized in the living way under the irradiation of blue light-emitting diodes (LEDs) or sunlight without photocatalyst at ambient temperature. 2-(Ethoxycarbonothioyl)sulfanyl propanoate is exclusively added and acts as initiator and chain transfer agent simultaneously in the current system. Poly(vinyl acetate) with well-regulated molecular weight and narrow molecular weight distribution (Đ < 1.30) is synthesized. Near quantitative end group fidelity of polymer is demonstrated by nuclear magnetic resonance (NMR) and matrix-assisteed laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

  9. High Molecular-Weight Thermoplastic Polymerization of Kraft Lignin Macromers with Diisocyanate

    Directory of Open Access Journals (Sweden)

    Le Dai Duong

    2014-03-01

    Full Text Available A high molecular-weight thermoplastic lignin-based polymer was successfully synthesized by adjusting the degree of polymerization while inducing linear growth of lignin macromers via methylene diphenyldiisocyanate. The thermoplastic lignin-urethane polymer was desirably achieved in a narrow range of reaction conditions of 2.5 to 3.5 h at 80 oC in this study, and the molecular weight of the resulting lignin-based polyurethanes (LigPU reached as high as 912,000 g/mole, which is far above any reported values of lignin-based polymer derivatives. The thermal stability of LigPU was greatly improved by the urethane polymerization, giving the initial degradation temperature (T2% at 204 °C, which should be compared with T2% = 104 °C of the pristine lignin. This was due to the fact that the OH groups in the lignin macromers, having low bond-dissociation energy, were replaced by the urethane bonds. In dielectric analysis, the synthesized LigPU exhibited a softening transition at 175 °C corresponding to a combinatorial dual process of the dry Tg,dry of the lignin macromers and the softening of methylenediphenyl urethane chains. This work clearly demonstrated that a high molecular weight of thermoplastic LigPU could be desirably synthesized, broadening the lignin application for value added and eco-friendly products through common melt processes of polymer blend or composites.

  10. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  11. Transparent polymeric cell culture chip with integrated temperature control and uniform media perfusion

    DEFF Research Database (Denmark)

    Petronis, Sarunas; Stangegaard, Michael; Christensen, C.

    2006-01-01

    Modern microfabrication and microfluidic technologies offer new opportunities in the design and fabrication of miniaturized cell culture systems for online monitoring of living cells. We used laser micromachining and thermal bonding to fabricate an optically transparent, low-cost polymeric chip...... for long-term online cell culture observation under controlled conditions. The chip incorporated a microfluidic flow equalization system, assuring uniform perfusion of the cell culture media throughout the cell culture chamber. The integrated indium-tin-oxide heater and miniature temperature probe linked...... to an electronic feedback system created steady and spatially uniform thermal conditions with minimal interference to the optical transparency of the chip. The fluidic and thermal performance of the chip was verified by finite element modeling and by operation tests under fluctuating ambient temperature conditions...

  12. Polymeric Shape-Memory Micro-Patterned Surface for Switching Wettability with Temperature

    Directory of Open Access Journals (Sweden)

    Nuria García-Huete

    2015-09-01

    Full Text Available An innovative method to switch the wettability of a micropatterned polymeric surface by thermally induced shape memory effect is presented. For this purpose, first polycyclooctene (PCO is crosslinked with dycumil peroxide (DCP and its melting temperature, which corresponds with the switching transition temperature (Ttrans, is measured by Dynamic Mechanical Thermal Analysis (DMTA in tension mode. Later, the shape memory behavior of the bulk material is analyzed under different experimental conditions employing a cyclic thermomechanical analysis (TMA. Finally, after creating shape memory micropillars by laser ablation of crosslinked thermo-active polycyclooctene (PCO, shape memory response and associated effect on water contact angle is analyzed. Thus, deformed micropillars cause lower contact angle on the surface from reduced roughness, but the original hydrophobicity is restored by thermally induced recovery of the original surface structure.

  13. Effect of water temperature on the fit of provisional crown margins during polymerization: An in vitro study

    Directory of Open Access Journals (Sweden)

    Vivekanandan Ramkumar

    2012-01-01

    Full Text Available Aim: To evaluate the effect of water temperature on the marginal fit of bis-acrylic composite provisional crown during resin polymerization. Materials and Methods: Precisely machined 10 brass master dies were designed to simulate molar teeth. Five brass dies were selected and precisely machined to simulate all ceramic crown preparation. An acrylic jaw replica was made in which brass dies were arranged equidistant from each other. A custom-made metallic tray was fabricated on the acrylic jaw replica to make polyvinyl siloxane impression matrix. Bis-acrylic composite resin provisional crowns were made using polyvinyl siloxane impression matrix. Provisional crowns were polymerized at room temperature (Group I direct technique, on dental stone cast; Group I indirect technique crowns and at different water temperatures (Group II direct technique crowns. The vertical marginal gap between all the provisional crown margins and the finish line of brass dies was measured using a Research Stereomicroscope System. Results: The results were statistically analyzed using one-way analysis of variance (ANOVA test and Newman-Keul′s test. The results showed that crowns polymerized in 20°C and 30°C water had marginal gap approximately three times smaller than those polymerized in 30°C air, due to the reduced polymerization shrinkage. Conclusion: This study shows that crowns polymerized in 20°C and 30°C water had mean vertical marginal gap approximately three times smaller than those polymerized in 30°C air. It was approximately closer to that of crowns fabricated by indirect technique. Warmer water also supposedly hastens polymerization.

  14. Advances in high temperature chemistry

    CERN Document Server

    Eyring, Leroy

    1969-01-01

    Advances in High Temperature Chemistry, Volume 2 covers the advances in the knowledge of the high temperature behavior of materials and the complex and unfamiliar characteristics of matter at high temperature. The book discusses the dissociation energies and free energy functions of gaseous monoxides; the matrix-isolation technique applied to high temperature molecules; and the main features, the techniques for the production, detection, and diagnosis, and the applications of molecular beams in high temperatures. The text also describes the chemical research in streaming thermal plasmas, as w

  15. Ultra-High Temperature Gratings

    Institute of Scientific and Technical Information of China (English)

    John Canning; Somnath Bandyopadhyay; Michael Stevenson; Kevin Cook

    2008-01-01

    Regenerated gratings seeded by type-Ⅰ gratings are shown to withstand temperatures beyond 1000 ℃. The method of regeneration offers a new approach to increasing temperature resistance of stable fibre Bragg and other gratings. These ultra-high temperature (UHT) gratings extend the applicability of silicate based components to high temperature applications such as monitoring of smelters and vehicle and aircraft engines to high power fibre lasers.

  16. High temperature nanoplasmonics

    Science.gov (United States)

    Alabastri, Alessandro; Toma, Andrea; Malerba, Mario; De Angelis, Francesco; Proietti Zaccaria, Remo

    2016-09-01

    Metallic nanostructures can be utilized as heat nano-sources which can find application in different areas such as photocatalysis, nanochemistry or sensor devices. Here we show how the optical response of plasmonic structures is affected by the increase of temperature. In particular we apply a temperature dependent dielectric function model to different nanoparticles finding that the optical responses are strongly dependent on shape and aspect-ratio. The idea is that when metallic structures interact with an electromagnetic field they heat up due to Joule effect. The corresponding temperature increase modifies the optical response of the particle and thus the heating process. The key finding is that, depending on the structures geometry, absorption efficiency can either increase or decrease with temperature. Since absorption relates to thermal energy dissipation and thus to temperature increase, the mechanism leads to positive or negative loops. Consequently, not only an error would be made by neglecting temperature but it would be not even possible to know, a priori, if the error is towards higher or lower values.

  17. Design of a self-tuning regulator for temperature control of a polymerization reactor.

    Science.gov (United States)

    Vasanthi, D; Pranavamoorthy, B; Pappa, N

    2012-01-01

    The temperature control of a polymerization reactor described by Chylla and Haase, a control engineering benchmark problem, is used to illustrate the potential of adaptive control design by employing a self-tuning regulator concept. In the benchmark scenario, the operation of the reactor must be guaranteed under various disturbing influences, e.g., changing ambient temperatures or impurity of the monomer. The conventional cascade control provides a robust operation, but often lacks in control performance concerning the required strict temperature tolerances. The self-tuning control concept presented in this contribution solves the problem. This design calculates a trajectory for the cooling jacket temperature in order to follow a predefined trajectory of the reactor temperature. The reaction heat and the heat transfer coefficient in the energy balance are estimated online by using an unscented Kalman filter (UKF). Two simple physically motivated relations are employed, which allow the non-delayed estimation of both quantities. Simulation results under model uncertainties show the effectiveness of the self-tuning control concept.

  18. Degradation of High Voltage Polymeric Insulators in Arid Desert's Simulated Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Yasin Khan

    2009-01-01

    Full Text Available Problem statement: High Voltage (HV polymeric insulators are replacing ceramic insulator commonly used for HV outdoor networks due to their ease of handling, reliability and cost. However, their long term performance and reliability are major concerns to power utilities. Approach: To investigate their performance in arid desert's conditions, two types of HV composite insulators were aged as per International Electrochemical Commission (IEC standard-61109. Additional test samples were subjected to accelerated aging conditions simulating the actual Ultraviolet (UV radiation intensity and temperature in the inland desert. Results: This study described the experimental results of the effects of thermo electric stress and UV radiations on the polymeric insulators aged under two conditions i.e., as per IEC standard and modified IEC standard that simulates the inland arid desert. The tests results after the artificial accelerated aging indicated that the dielectric response of thermoplastic insulators under the tested thermo-electric cum UV-irradiations outperforms Silicone rubber insulators.Conclusion: From the obtained results it will be easy to assess the performance and suitability of composite insulators for their applications in arid desert environments.

  19. N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0 Nanoparticules

    Directory of Open Access Journals (Sweden)

    Mohamad-Ali Tehfe

    2015-08-01

    Full Text Available N-vinylcarbazole (NVK is proposed as an additive for acrylates thermal free radical polymerization (FRP and epoxy thermal ring opening polymerization (ROP at room temperature. The new initiating systems are based on a silane/silver salt/N-vinylcarbazole interaction, which ensures good to excellent polymerization. Moreover, the polymerization is much more efficient under air than under argon. The effects of the N-vinylcarbazole, silane, silver salt and monomer structures are investigated. Interestingly, silver nanoparticles Ag(0 are formed in situ. The as-synthesized nanocomposite materials contained spherical nanoparticles homogeneously dispersed in the polymer matrices. Polymers and nanoparticles were characterized by Differential Scanning Calorimetry (DSC, Transmission Electron Microscopy (TEM, Energy-Dispersive X-ray Spectrometry (EDS, Fourier Transform Infrared Spectroscopy (FTIR, and UV-vis spectroscopy. A coherent picture of the involved chemical mechanisms is presented.

  20. KINETICS OF VINYL CHLORIDE (CO)POLYMERIZATION AT HIGH CONVERSION

    Institute of Scientific and Technical Information of China (English)

    Zu-ren Pan; Zhi-xue Weng; Zhi-ming Huang

    1999-01-01

    This paper provides a summarized review on the kinetics of vinyl chloride homopolymerization in the absence and presence of chain transfer agents, of VC/DAP(diallyl phthalate) copolymerization with chain extension and/or slightly crosslinking functions, and of vinylidene chloride/VC random copolymerization.Models of rate, degree of polymerization or molecular weight, copolymer composition, gel fraction and crosslinking density were proposed and interpreted mechanistically.

  1. Preparation of reactive macroporous polymeric beads for high-performance liquid chromatography applications: Polymerization, surface modification and characterization

    Science.gov (United States)

    Liang, Yi-Chun

    Several stationary phases for high performance liquid chromatography (HPLC) based on synthetic polymers with controlled pore structures and surface chemistries have been prepared and characterized. The first part of the research is focused on the control of pore structure of reactive beads prepared from functional monomers such as 2,3-epoxypropyl vinylbenzyl ether and 2,3-epoxypropyl vinylbenzyl ether with divinylbenzene used as a crosslinker. Due to a relatively large difference in polarities of these two functional monomers, a new porogenic system had to be developed for the preparation of monodisperse beads from 2,3-epoxypropyl vinylbenzyl ether. In contrast, polymerization conditions similar to those used for the preparation of poly(styrene-co-divinylbenzene) beads can be used for the systems involving chloromethylstyrene and divinylbenzene. An extensive study of the effects of various polymerization parameters on the properties of these reactive beads was carried out in order to achieve fine control over the degree of functionalization and pore structure. The second part of the research is focused on the surface modification of reactive beads prepared in the previous study for the HPLC separation of enantiomers. The performance of our chiral stationary phases (CSP) with brush-type selectors was comparable to the best silica-based chiral separation media. As a part of this study, polymeric CSPs with different linkages, tethers, loading levels, and backbone structures were prepared and characterized. Another series of CSPs were prepared from beads functionalized with a poly(propylene imine) dendrimer tether. A high coupling efficiency with the chiral selector was characteristic of the polymer support modified with dendrimers, and these dendritic supports demonstrated the substantial contribution of linkers with multiple functionalities originating from a single surface site to the selectivity and efficiency of the polymer based separation media.

  2. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  3. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and dev

  4. Effect of high-pressure polymerization on mechanical properties of PMMA denture base resin.

    Science.gov (United States)

    Murakami, Natsuko; Wakabayashi, Noriyuki; Matsushima, Rie; Kishida, Akio; Igarashi, Yoshimasa

    2013-04-01

    The aim of this study was to assess the effect of high-pressure polymerization on mechanical properties of denture base resin. A heat-curing denture base resin and an experimental PMMA were polymerized under 500MPa of pressure by means of an isostatic pressurization machine at 70°C for 24h to make rectangular specimens whose dimensions were 30mm×2mm×2mm. Each specimen was deflected on a three-point flexural test until either fracture occurred or the sample was loaded up to 8mm in deflection. The molecular weight of the PMMA without filler was analyzed using the high-speed liquid chromatography system. Increased ductility without fracture was shown in the specimens subjected to high pressure, while most of the control specimens (ambient pressure) fractured. The mean toughness of the PMMA specimens polymerized under the high pressure was significantly higher than the same material polymerized under ambient pressure (ppressure groups of the denture resin and the PMMA revealed a significantly lower mean 0.2% yield stress, flexural strength, and elastic modulus than control groups (ppressure specimens than were present in the controls. The increased toughness shown in the PMMA polymerized under the high pressure was presumably attributed to the higher molecular weight produced by the pressure. The result suggests a potential application of the high-pressure polymerization to the development of PMMA-based denture resin with improved fracture resistance.

  5. High temperature materials; Materiaux a hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  6. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  7. Mechanical-property changes of polymeric and composite materials after low-temperature proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Snead, C.L. Jr.; Czajkowski, C.J.; Skaritka, J. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology; Morena, J. [Ace Inc., Stuart, FL (United States)

    1999-02-01

    The mechanical properties of polymeric and composite materials are known to be sensitive to ionizing radiation. Most of the existing data, however, is the result of near-room-temperature irradiations, most commonly with {sup 60}Co gamma irradiation. For use of these materials in applications such as for magnetic fusion magnets, where operation will be at cryogenic temperatures in sometimes severe radiation fields, knowledge of the materials` radiation response to low-temperature irradiations is required. This paper reports the results of mechanical-property-change measurements made at 4.2K on a number of potential magnet materials following 200-MeV-proton irradiation at temperatures below 20K. Standard three-point bend tests were performed at 4.2K for short-beam shear determinations in the laminate materials and for shear strength in the remainder of the specimens. Specimens were warmed to room temperature for one week prior to the mechanical testing in order to emulate the expected the expected mechanical state of the material assuming room-temperature cycling in the expected magnet applications. Data are presented in the form of yield stresses before and after irradiations with percentages of change. There were five specimens per test dose for each material. Data are presented for exposures ranging from nominally 10{sup 7} to 10{sup 9} rad. Results of the mechanical tests range from complete delamination and distortion of the specimens at 10{sup 9} rad to an increase in the yield stress of 63% after 10{sup 9} rad. The latter specimen did, however, evidence significant embrittlement. The phenomenon of irradiation-induced strengthening due to enhanced cross linking in undercured polymers was observed in some cases.

  8. New directions for high-performance materials via postextrusion solid state polymerization

    Science.gov (United States)

    Almonacil, Celine

    Solid state polymerization (SSP) usually consists of heating condensation polymers to temperatures below their melting point and holding there for a significant time to raise their molecular weight. The process is common in the polymer industry for the production of high molecular weight polyesters and polyamides for industrial fibers and molded products. Recent research has shown that post-extrusion SSP, where polymerization is performed on extruded products such as thin films or fibers, has the potential to lead to high performance materials. Although literature on SSP is abundant, the mechanisms and possible morphological consequences have remained largely unexplored. The purpose of this work is to explore the potential for generating high performance oriented polymer morphologies by performing a fundamental analysis of the mechanisms and morphological consequences of post-extrusion SSP in oriented polymers. It is based on recent research that has shown that interchange reactions can play a fundamental role during many solid state polymerizations by providing the primary mechanism for migration of functionality. It is also based on the recent recognition that these reactions can cause profound changes in the morphology of the polymer. A coarse-grained model which can be used to explore quantitatively the effect of interchange reactions on the topological distribution of chains in inter-crystalline regions is presented here. It includes a novel thermodynamic scheme, coupled with Monte Carlo Rotational Isomeric State simulations, to determine quantitatively the relative probabilities of morphologically different reaction pathways. The results show the role of intrinsic molecular rigidity on interconversions of bridges and loops during SSP of different polymers. The generalized scheme presented here can serve to identify, via gedanken experiments, appropriate semi-rigid systems to explore through real synthesis and processing of high mechanical performance polymers

  9. Highly Defined Multiblock Copolypeptoids: Pushing the Limits of Living Nucleophilic Ring-Opening Polymerization

    KAUST Repository

    Fetsch, Corinna

    2012-06-05

    Advanced macromolecular engineering requires excellent control over the polymerization reaction. Living polymerization methods are notoriously sensitive to impurities, which makes a practical realization of such control very challenging. Reversible-deactivation radical polymerization methods are typically more robust, but have other limitations. Here, we demonstrate by repeated (ge;10 times) chain extension the extraordinary robustness of the living nucleophilic ring-opening polymerization of N-substituted glycine N-carboxyanhydrides, which yields polypeptoids. We observe essentially quantitative end-group fidelity under experimental conditions that are comparatively easily managed. This is employed to synthesize a pentablock quinquiespolymer with high definition. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Free radical suspension polymerization kinetics of styrene up to high conversion

    NARCIS (Netherlands)

    Tefera, Nurelegne; Weickert, Günter; Bloodworth, Robert; Schweer, Johannes

    1994-01-01

    Styrene was polymerized using different amounts of azoisobutyronitrile as initiator at temperatures of 70°C, 75°C and 80°C in suspension. The course of reaction up to almost complete conversion was modeled within a classical kinetic framework. Optimal simultaneous descriptions of both conversion and

  11. High Temperature Electrostrictive Ceramics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop high temperature electrostrictors from bismuth-based ferroelectrics. These materials will exhibit high strain and low loss in...

  12. Measurements of the temperature dependence of radiation induced conductivity in polymeric dielectrics

    Science.gov (United States)

    Gillespie, Jodie

    This study measures Radiation Induced Conductivity (RIC) in five insulating polymeric materials over temperatures ranging from ~110 K to ~350 K: polyimide (PI or Kapton HN(TM) and Kapton E(TM)), polytetraflouroethylene (PTFE or Teflon(TM)), ethylene-tetraflouroethylene (ETFE or Tefzel(TM)), and Low Density Polyethylene (LDPE). RIC occurs when incident ionizing radiation deposits energy and excites electrons into the conduction band of insulators. Conductivity was measured when a voltage was applied across vacuum-baked, thin film polymer samples in a parallel plate geometry. RIC was calculated as the difference in sample conductivity under no incident radiation and under an incident ~4 MeV electron beam at low incident dose rates of 0.01 rad/sec to 10 rad/sec. The steady-state RIC was found to agree well with the standard power law relation, sigmaRIC(D˙) = kRIC(T) D˙Delta(T) between conductivity, sigmaRIC and adsorbed dose rate, D˙. Both the proportionality constant, kRIC, and the power, Delta, were found to be temperature-dependent above ~250 K, with behavior consistent with photoconductivity models developed for localized trap states in disordered semiconductors. Below ~250 K, kRIC and Delta exhibited little change in any of the materials.

  13. A Novel Continuously Initiated Polymerization by One-Atmosphere Low Temperature Plasma Device

    Institute of Scientific and Technical Information of China (English)

    You qingliang; Meng yuedong; Wang jianhua; Ou qiongrong; Xu xu; Zhong shaofeng

    2005-01-01

    A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.

  14. Effect of additives on the properties of polyaniline nanofibers prepared by high gravity chemical oxidative polymerization.

    Science.gov (United States)

    Zhao, Yibo; Arowo, Moses; Wu, Wei; Chen, Jianfeng

    2015-05-12

    Polyaniline (PANI) nanofibers with improved properties were prepared by high gravity chemical oxidative polymerization in a rotating packed bed with the assistance of p-aminodiphenylamine (AD) and p-phenylenediamine (AP). The effects of reactor type, additive dosage, reaction temperature, and high-gravity level on the properties of products were investigated in detail. Three conclusions were made: (1) a small amount of additive can significantly improve some properties of the nanofibers such as uniformity, specific surface area, and specific capacitance; (2) in order to obtain high-quality nanofibers, the high-gravity level should coordinate with the reaction rate; (3) the molecular weight and conductivity of PANI decrease with the increase of additive dosage. The products have larger specific surface areas of up to 73.9 and 68.4 m(2)/g and consequently improved specific capacitance of up to 527.5 and 552 F/g for the PANI nanofibers prepared with AD and AP, respectively. However, the specific surface area and specific capacitance of pure PANI are only 49.1 m(2)/g and 333.3 F/g, respectively. This research provides a simple, reliable, and scalable method to produce PANI nanofibers of high performances.

  15. Thermodynamics of High Temperature Materials.

    Science.gov (United States)

    1986-09-30

    9S l~ SECUNT’~ C..&SSFCAr’CN OF ’-S OAGE REPORT DOCUMENTATION PAGE I &. EPO RT SEC URNITY CLASS P’CATION lb. RE£ST R CT IV I dAUNLSSIFIED M 4 j7...34 - :ne polymeric ions, and the repair mechanisms which regenerated the , polymeric ions after photodissociation. The model systems studied previously

  16. Influence of the material for preformed moulds on the polymerization temperature of resin materials for temporary FPDs.

    Science.gov (United States)

    Pott, Philipp-Cornelius; Schmitz-Wätjen, Hans; Stiesch, Meike; Eisenburger, Michael

    2017-08-01

    Temperature increase of 5.5 ℃ can cause damage or necrosis of the pulp. Increasing temperature can be caused not only by mechanical factors, e.g. grinding, but also by exothermic polymerization reactions of resin materials. The aim of this study was to evaluate influences of the form material on the intrapulpal temperature during the polymerization of different self-curing resin materials for temporary restorations. 30 provisonal bridges were made of 5 resin materials: Prevision Temp (Pre), Protemp 4 (Pro), Luxatemp Star (Lux), Structure 3 (Str) and an experimental material (Exp). Moulds made of alginate (A) and of silicone (S) and vacuum formed moulds (V) were used to build 10 bridges each on a special experimental setup. The intrapulpal temperatures of three abutment teeth (a canine, a premolar, and a molar,) were measured during the polymerization every second under isothermal conditions. Comparisons of the maximum temperature (TMax) and the time until the maximum temperature (tTMax) were performed using ANOVA and Tukey Test. Using alginate as the mould material resulted in a cooling effect for every resin material. Using the vacuum formed mould, TMax increased significantly compared to alginate (Pmaterial on tTMax. All of the mould materials are suitable for clinical use if the intraoral application time does not exceed the manufacturer's instructions for the resin materials.

  17. Calcium chloride doped zinc-cobalt metal-cyanide complex: Unexpected highly activity towards ring-opening polymerization of propylene oxide

    Institute of Scientific and Technical Information of China (English)

    Yi Jun Huang; Xing Hong Zhang; Zheng Jiang Hua; Guo Rong Qi

    2010-01-01

    Highly active calcium chloride (CaCl2) doped Zn-CoⅢ double metal-cyanide (Ca-DMC) catalysts were firstly reported. Ca-DMCs presented a very higher polymer yield (54 kg polymer/g catalyst) at relative low temperature (80-115 ℃) toward ring-opening polymerization (ROP) of propylene oxide (PO) than did DMC catalysts without modification.

  18. Highly durable and unidirectionally stooped polymeric nanohairs for gecko-like dry adhesive

    Science.gov (United States)

    Im, Hyeon Seong; Kwon, Ki Yoon; Kim, Jong Uk; Kim, Kwang Su; Yi, Hoon; Yoo, Pil J.; Pang, Changhyun; Jeong, Hoon Eui; Kim, Tae-il

    2015-10-01

    Gecko-like dry adhesive using high aspect ratio polymeric nanohairs has insuperable limitations, although it has huge potential in many applications. Repeated harsh contacts on a target substrate lead to physical collapse of nanohairs and significant degradation of the adhesion property, because the polymeric nanohairs are quite fragile due to poor mechanical robustness. Herein, we demonstrate a highly robust gecko-like dry adhesive with unidirectionally stooped polymeric nanohairs (diameter 100 nm) with a high aspect ratio (∼9) using an ultrathin metal coating. 100 cycles of repeated adhesion tests with 1 N preloading force did not significantly degrade adhesion or cause collapse of nanohairs. We believe that this approach allows gecko-like dry adhesive to be utilized in many related applications and diverse industry interests.

  19. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  20. High-rate stormwater clarification with polymeric flocculant addition.

    Science.gov (United States)

    Wood, J; He, C; Rochfort, Q; Marsalek, J; Seto, P; Yang, M; Chessie, P; Kok, S

    2005-01-01

    Treatment of urban stormwater by clarification, with flocculant addition, was studied in Toronto, Canada using a pilot-scale clarifier with removable lamellar plates. Almost 90 stormwater runoff events were characterised at the study site and found fairly polluted. The previous research phase indicated good treatability of this stormwater by lamellar clarification with flocculant addition (total suspended solids, TSS, removal of 84%, at a surface load of 15 m/h), but there were concerns about cleaning plates after storm events. With the aid of numerical modelling, hydraulic improvements to the clarifier inlet zone were retrofitted in 2004 and permitted the removal of the lamellar pack without a loss in treatment efficiency. In the modified clarifier, a cationic polymeric flocculant dosage of 4 mg/L with conventional clarification provided a TSS removal of 77%, at surface loads up to 43 m/h. The use of the polymer did not increase the acute toxicity of the treated effluent. The clarifier sludge was severely polluted by several heavy metals and would require special disposal. The treatment process tested could be well applied in projects requiring intensive stormwater treatment at compact sites.

  1. High Temperature Bell Motor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The National Research Council (NRC) has identified the need for motors and actuators that can operate in extreme high and low temperature environments as a technical...

  2. High Temperature Materials Laboratory (HTML)

    Data.gov (United States)

    Federal Laboratory Consortium — The six user centers in the High Temperature Materials Laboratory (HTML), a DOE User Facility, are dedicated to solving materials problems that limit the efficiency...

  3. Highly conductive free standing polypyrrole films prepared by freezing interfacial polymerization.

    Science.gov (United States)

    Qi, Guijin; Huang, Liyan; Wang, Huiliang

    2012-08-25

    Highly conductive free standing polypyrrole (PPy) films were prepared by a novel freezing interfacial polymerization method. The films exhibit metallic luster and electrical conductivity up to 2000 S cm(-1). By characterizing with SEM, FTIR, Raman and XRD, the high conductivity is attributed to the smooth surface, higher conjugation length and more ordered molecular structure of PPy.

  4. A high-order Immersed Boundary method for the simulation of polymeric flow

    Science.gov (United States)

    Stein, David; Thomases, Becca; Guy, Robert

    2016-11-01

    We present a robust, flexible, and high-order Immersed Boundary method for simulating fluid flow, including the Incompressible Navier-Stokes equations and certain models of viscoelastic flow, e.g. the Stokes-Oldroyd-B equations. The solution to the PDE is coupled with an equation for a smooth extension of the unknown solution; high-order accuracy is a natural consequence of this additional global regularity. Low and zero Reynolds number problems are handled efficiently and accurately. We demonstrate pointwise convergence of the polymeric stress for flows in complex domains, in contrast to the standard Immersed Boundary method, which generates large errors in the polymeric stress near to the boundaries.

  5. Proton conducting, high modulus polymer electrolyte membranes by polymerization-induced microphase separation

    Science.gov (United States)

    Chopade, Sujay; Hillmyer, Marc; Lodge, Timothy

    Robust solid-state polymer electrolyte membranes (PEMs) are vital for designing next-generation lithium-ion batteries and high-temperature fuel cells. However, the performance of diblock polymer electrolytes is generally limited by poor mechanical stability and network defects in the conducting pathways. We present the in-situ preparation of robust cross-linked PEMs via polymerization-induced microphase separation, and incorporation of protic ionic liquid (IL) into one of the microphase separated domains. The facile design strategy involves a delicate balance between the controlled growth of polystyrene from a poly(ethylene oxide) macro-chain transfer agent (PEO-CTA) and simultaneous chemical cross-linking by divinylbenzene in the presence of IL. Small angle X-ray scattering and transmission electron microscopy confirmed the formation of a disordered structure with bicontinuous morphology and a characteristic domain size of order 20 nm. The long-range continuity of the PEO/protic IL conducting nanochannels and cross-linked polystyrene domains imparts high thermal and mechanical stability to the PEMs, with elastic modulus approaching 10 MPa and a high ionic conductivity of 15 mS/cm at 180 °C.

  6. Fabrication of Highly Ordered Polymeric Nanodot and Nanowire Arrays Templated by Supramolecular Assembly Block Copolymer Nanoporous Thin Films

    Directory of Open Access Journals (Sweden)

    Liu Xikui

    2009-01-01

    Full Text Available Abstract Realizing the vast technological potential of patternable block copolymers requires both the precise controlling of the orientation and long-range ordering, which is still a challenging topic so far. Recently, we have demonstrated that ordered nanoporous thin film can be fabricated from a simple supramolecular assembly approach. Here we will extend this approach and provide a general route to fabricate large areas of highly ordered polymeric nanodot and nanowire arrays. We revealed that under a mixture solvent annealing atmosphere, a near-defect-free nanoporous thin film over large areas can be achieved. Under the direction of interpolymer hydrogen bonding and capillary action of nanopores, this ordered porous nanotemplate can be properly filled with phenolic resin precursor, followed by curation and pyrolysis at middle temperature to remove the nanotemplate, a perfect ordered polymer nanodot arrays replication was obtained. The orientation of the supramolecular assembly thin films can be readily re-aligned parallel to the substrate upon exposure to chloroform vapor, so this facile nanotemplate replica method can be further extend to generate large areas of polymeric nanowire arrays. Thus, we achieved a successful sub-30 nm patterns nanotemplates transfer methodology for fabricating polymeric nanopattern arrays with highly ordered structure and tunable morphologies.

  7. Highly efficient and selective pressure-assisted photon-induced polymerization of styrene

    Science.gov (United States)

    Guan, Jiwen; Song, Yang

    2016-06-01

    The polymerization process of condensed styrene to produce polystyrene as an industrially important polymeric material was investigated using a novel approach by combining external compression with ultraviolet radiation. The reaction evolution was monitored as a function of time and the reaction products were characterized by in situ Fourier transform infrared spectroscopy. By optimizing the loading pressures, we observed highly efficient and selective production of polystyrene of different tacticities. Specifically, at relatively low loading pressures, infrared spectra suggest that styrene monomers transform to amorphous atactic polystyrene (APS) with minor crystalline isotactic polystyrene. In contrast, APS was found to be the sole product when polymerization occurs at relatively higher loading pressures. The time-dependent reaction profiles allow the examination of the polymerization kinetics by analyzing the rate constant and activation volume as a function of pressure. As a result, an optimized pressure condition, which allows a barrierless reaction to proceed, was identified and attributed to the very desirable reaction yield and kinetics. Finally, the photoinitiated reaction mechanism and the growth geometry of the polymer chains were investigated from the energy diagram of styrene and by the topology analysis of the crystal styrene. This study shows strong promise to produce functional polymeric materials in a highly efficient and controlled manner.

  8. Gallium phosphide high temperature diodes

    Science.gov (United States)

    Chaffin, R. J.; Dawson, L. R.

    1981-01-01

    High temperature (300 C) diodes for geothermal and other energy applications were developed. A comparison of reverse leakage currents of Si, GaAs, and GaP was made. Diodes made from GaP should be usable to 500 C. A Liquid Phase Epitaxy (LPE) process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers were cut into die and metallized to make the diodes. These diodes produce leakage currents below ten to the -9th power A/sq cm at 400 C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.

  9. RPC operation at high temperature

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Stante, L; Liberti, B; Paoloni, A; Pastori, E; Santonico, R

    2003-01-01

    The resistive electrodes of RPCs utilised in several current experiments (ATLAS, CMS, ALICE, BABAR and ARGO) are made of phenolic /melaminic polymers, with room temperature resistivities ranging from 10**1**0 Omega cm, for high rate operation in avalanche mode, to 5 multiplied by 10**1**1 Omega cm, for streamer mode operation at low rate. The resistivity has however a strong temperature dependence, decreasing exponentially with increasing temperature. We have tested several RPCs with different electrode resistivities in avalanche as well as in streamer mode operation. The behaviours of the operating current and of the counting rate have been studied at different temperatures. Long-term operation has also been studied at T = 45 degree C and 35 degree C, respectively, for high and low resistivity electrodes RPCs.

  10. Temperature optimization of high con

    Directory of Open Access Journals (Sweden)

    M. Sabry

    2016-06-01

    Full Text Available Active cooling is essential for solar cells operating under high optical concentration ratios. A system comprises four solar cells that are in thermal contact on top of a copper tube is proposed. Water is flowing inside the tube in order to reduce solar cells temperature for increasing their performance. Computational Fluid Dynamics (CFD simulation of such system has been performed in order to investigate the effect of water flow rate, tube internal diameter, and convective heat transfer coefficient on the temperature of the solar cells. It is found that increasing convective heat transfer coefficient has a significant effect on reducing solar cells temperatures operating at low flow rates and high optical concentration ratios. Also, a further increase of water flow rate has no effect on reducing cells temperatures.

  11. HIgh Temperature Photocatalysis over Semiconductors

    Science.gov (United States)

    Westrich, Thomas A.

    Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a

  12. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...... temperature allows for utilization of the excess heat for fuel processing. Moreover, it provides an excellent CO tolerance of several percent, and the system needs no purification of hydrogen from a reformer. Continuous service for over 6 months at 150°C has been demonstrated....

  13. Eu(3+)-mediated polymerization of benzenetetracarboxylic acid studied by spectroscopy, temperature-dependent calorimetry, and density functional theory.

    Science.gov (United States)

    Barkleit, Astrid; Tsushima, Satoru; Savchuk, Olesya; Philipp, Jenny; Heim, Karsten; Acker, Margret; Taut, Steffen; Fahmy, Karim

    2011-06-20

    Thermodynamic parameters for the complexation of Eu(3+) with pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid, BTC) as a model system for polymerizable metal-complexing humic acids were determined using temperature-dependent time-resolved laser-induced fluorescence spectroscopy (TRLFS) and isothermal titration calorimetry (ITC). At low metal and ligand concentrations (+), 500 μM Eu(3+) and BTC) a temperature-dependent polymerization was observed, where BTC monomers are linked via coordinating shared Eu(3+) ions. The two methods lead to comparable thermodynamic data (ΔH = 18.5 ± 1.5/16.5 ± 0.1 kJ mol(-1); ΔS = 152 ± 5/130 ± 5 J mol(-1) K(-1); TRLFS/ITC) in the absence of polymerization. With the onset of polymerization, TRLFS reveals the water coordination number of the lanthanide, whereas calorimetry is superior in determining the thermodynamic data in this regime. Evaluating the heat uptake kinetics, the monomer and polymer formation steps could be separated by "time-resolved" ITC, revealing almost identical binding enthalpies for the sequential reactions. Structural features of the complexes were studied by Fourier-transform infrared (FTIR) spectroscopy in combination with density functional theory (DFT) calculations showing predominantly chelating coordination with two carboxylate groups in the monomeric complex and monodentate binding of a single carboxylate group in the polymeric complex of the polycarboxylate with Eu(3+). The data show that pyromellitic acid is a suitable model for the study of metal-mediated polymerization as a crucial factor in determining the effect of humic acids on the mobility of heavy metals in the environment.

  14. Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High selective molecularly imprinted polymers (MIPs) for tetracycline have been prepared by precipitation polymerization.Effects of monomer and solvent, the ratio of monomer and template and the characterization of the polymer were investigated by frontal chromatography and selectivity experiment. The results clearly indicated that the polymer, which had the highest molecular recognition abilities for tetracycline antibiotics, had been received.

  15. Interface high-temperature superconductivity

    Science.gov (United States)

    Wang, Lili; Ma, Xucun; Xue, Qi-Kun

    2016-12-01

    Cuprate high-temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in the semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high-temperature superconductivity in ultra-thin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface-enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high-temperature superconductivity with a superconducting gap of ∼20 meV in 1UC-FeSe/STO has stimulated tremendous interest in the superconductivity community, for it opens a new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high-temperature superconductivity. Here, we review mainly the experimental progress on interface-enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and a possible pairing mechanism inferred from these studies.

  16. High-Temperature Optical Sensor

    Science.gov (United States)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  17. High temperature superconductor current leads

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Hinsdale, IL); Poeppel, Roger B. (Glen Ellyn, IL)

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  18. High temperature polymer matrix composites

    Science.gov (United States)

    Serafini, Tito T. (Editor)

    1987-01-01

    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) Characterization; (4) environmental effects; and (5) applications.

  19. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  20. Evaluation of polymeric gene delivery nanoparticles by nanoparticle tracking analysis and high-throughput flow cytometry.

    Science.gov (United States)

    Shmueli, Ron B; Bhise, Nupura S; Green, Jordan J

    2013-03-01

    Non-viral gene delivery using polymeric nanoparticles has emerged as an attractive approach for gene therapy to treat genetic diseases(1) and as a technology for regenerative medicine(2). Unlike viruses, which have significant safety issues, polymeric nanoparticles can be designed to be non-toxic, non-immunogenic, non-mutagenic, easier to synthesize, chemically versatile, capable of carrying larger nucleic acid cargo and biodegradable and/or environmentally responsive. Cationic polymers self-assemble with negatively charged DNA via electrostatic interaction to form complexes on the order of 100 nm that are commonly termed polymeric nanoparticles. Examples of biomaterials used to form nanoscale polycationic gene delivery nanoparticles include polylysine, polyphosphoesters, poly(amidoamines)s and polyethylenimine (PEI), which is a non-degradable off-the-shelf cationic polymer commonly used for nucleic acid delivery(1,3) . Poly(beta-amino ester)s (PBAEs) are a newer class of cationic polymers(4) that are hydrolytically degradable(5,6) and have been shown to be effective at gene delivery to hard-to-transfect cell types such as human retinal endothelial cells (HRECs)(7), mouse mammary epithelial cells(8), human brain cancer cells(9) and macrovascular (human umbilical vein, HUVECs) endothelial cells(10). A new protocol to characterize polymeric nanoparticles utilizing nanoparticle tracking analysis (NTA) is described. In this approach, both the particle size distribution and the distribution of the number of plasmids per particle are obtained(11). In addition, a high-throughput 96-well plate transfection assay for rapid screening of the transfection efficacy of polymeric nanoparticles is presented. In this protocol, poly(beta-amino ester)s (PBAEs) are used as model polymers and human retinal endothelial cells (HRECs) are used as model human cells. This protocol can be easily adapted to evaluate any polymeric nanoparticle and any cell type of interest in a multi

  1. Nonlinear plasmonics at high temperatures

    CERN Document Server

    Sivan, Yonatan

    2016-01-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on {\\em experimentally}-measured data for the metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution, and thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modelling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high temperature non...

  2. Nonlinear plasmonics at high temperatures

    Directory of Open Access Journals (Sweden)

    Sivan Yonatan

    2017-01-01

    Full Text Available We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  3. Nonlinear plasmonics at high temperatures

    Science.gov (United States)

    Sivan, Yonatan; Chu, Shi-Wei

    2017-01-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  4. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  5. Temperature-responsive polymeric nanospheres containing methotrexate and gold nanoparticles: A multi-drug system for theranostic in rheumatoid arthritis.

    Science.gov (United States)

    Costa Lima, Sofia A; Reis, Salette

    2015-09-01

    Inflammation plays a crucial role in rheumatoid arthritis progress. In the present work, a novel stealth polymeric nanospheres platform able to carry anti-inflammatory drugs and an imaging agent was developed. Incorporation of gold nanoparticles will allow photoacoustic imaging and near infra-red photothermal application. Through emulsion-diffusion evaporation technique methotrexate and gold nanoparticles were incorporated in the pegylated-poly(DL-lactic-co-glycolic acid) nanospheres. In vitro drug release assays revealed pH and temperature-dependence on gold nanoparticles. Blank nanospheres exhibited negligible in vitro cytotoxicity, while methotrexate-loaded nanospheres hampered monocytes and macrophages viability at a higher level than free methotrexate. Confocal fluorescent microscopy and flow cytometry revealed effective nanospheres internalization, and that their cellular uptake was energy dependent mediated by caveolae and clathrin-endocytosis mechanism. Finally, MTX-loaded multifunctional nanospheres containing gold lead to a significant reduction of IL-1β, IL-6 and TNF-α inflammatory cytokines produced by monocytes and macrophages upon in vitro inflammatory stimulation, suggesting a favorable anti-inflammatory activity. These results confirm that the multifunctional nanospheres represent a promising theranostic platform for RA diagnosis and intracellular treatment, by combining methotrexate and gold nanoparticles for a highly effective targeted chemo-photothermal therapy.

  6. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  7. Properties of high temperature SQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Falco, C. M.; Wu, C. T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb/sub 3/Sn is outlined, and comments are made on directions future work should take.

  8. High Modulus, High Conductivity Nanostructured Polymer Electrolyte Membranes via Polymerization-Induced Phase Separation

    Science.gov (United States)

    McIntosh, Lucas; Schulze, Morgan; Hillmyer, Marc; Lodge, Timothy

    2014-03-01

    Solvent-free, solid-state polymer electrolyte membranes (PEMs) will play a vital role in next-generation electrochemical devices such as Li-metal batteries and high- T fuel cells. The primary challenge is that these applications require PEMs with substantial mechanical robustness, as well as high ionic conductivity. The key to optimizing orthogonal macroscopic properties is to use a heterogeneous composite with well-defined nanoscopic morphology--specifically, long-range co-continuity of high modulus and ion transport domains, which has proven difficult to achieve in commonly-studied diblock copolymer-based electrolytes. We report a simple synthetic strategy to generate PEMs via polymerization-induced phase separation, where the delicate balance between controlled addition of styrene onto a poly(ethylene oxide) macro-chain transfer agent and simultaneous chemical crosslinking by divinylbenzene results in a disordered structure with domain size of order 10 nm. Crucially, both domains exhibit long-range continuity, which results in PEMs that are glassy solids (modulus ~ 1 GPa) owing to the isotropic network of stiff, crosslinked polystyrene, and are highly conductive (> 1 mS/cm at 70 °C) because ions migrate in channels of low Tg poly(ethylene oxide).

  9. The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

    Science.gov (United States)

    Enomoto, Ichiro; Katsumura, Yosuke; Kudo, Hisaaki; Sekiguchi, Masayuki

    2010-06-01

    A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 γ-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

  10. The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Ichiro, E-mail: enomoto.ichiro@iri-tokyo.j [Tokyo Metropolitan Industrial Technology Research Institute, KFC bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan); School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Katsumura, Yosuke [School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Ibaraki 319-1195 (Japan); Kudo, Hisaaki [School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Sekiguchi, Masayuki [Tokyo Metropolitan Industrial Technology Research Institute, KFC bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan)

    2010-06-15

    A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 gamma-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

  11. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  12. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

    Full Text Available Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  13. High Temperature Sorbents for Oxygen

    Science.gov (United States)

    Sharma, Pramod K. (Inventor)

    1996-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C is introduced. The sorbent comprises a porous alumina silicate support such as zeolite containing from 1 to 10 percent by weight of ion exchanged transition metal such as copper or cobalt ions and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum. The activation temperature, oxygen sorption and reducibility are all improved by the presence of the platinum activator.

  14. Solid state polymerization of pet/pc extruded blend: effect of reaction temperature on thermal, morphological and viscosity properties

    Directory of Open Access Journals (Sweden)

    Luis Claudio Mendes

    2014-08-01

    Full Text Available A systematic study of solid state polymerization (SSP, concerning the melt extruded blend of poly(ethylene terephthalate/polycarbonate (catalyzed PET/PC, 80/20 wt %, as a function of temperature range (180-190°C for a fixed time (6 h is presented. The materials obtained were evaluated by differential scanning calorimetry (DSC, thermogravimetry/derivative thermogravimetry (TG/DTG, optical microscopy (OM and intrinsic viscosity (IV analysis. After SSP, at all reaction temperatures, PET glass transition and heating crystallization temperatures slightly decreased, melting temperature slightly increased, while degree of crystallinity was practically invariable. The DTG curves indicated that, at least, three phases remained. The OM images revealed that the morphology is constituted of a PET matrix and a PC dispersed phase. In the interfacial region we noticed the appearance of structures like bridges linking the matrix and the dispersed domains. These bridges were correlated to the PET/PC block copolymer obtained during blending in the molten state. IV increased for all polymerization temperatures, due to the occurrence of PET chain extension reactions - esterification and transesterification. The IV range for bottle grade PET was achieved.

  15. High-temperature beryllium embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovsky, A.S. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation); Fabritsiev, S.A. [D.V. Efremov Scientific Research Institute, 189631 St. Petersburg (Russian Federation); Bagautdinov, R.M. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation); Goncharenko, Yu.D. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation)

    1996-10-01

    The neutron irradiation effect on the mechanical properties, swelling and fracture surface structure of various beryllium grades was studied in the BOR-60 reactor at 340 to 350 C up to a fluence of 7.2 x 10{sup 21} n/cm{sup 2}. At a mechanical testing temperature of 400 C there was observed a strong anisotropy of plastic beryllium deformation depending on the direction of sample cutting relative to the pressing direction. An increase of the testing temperature up to 700 C resulted in an abrupt embrittlement of all irradiated samples. In the most part of the surface structure the intercrystallite fracture along the grain boundaries was covered entirely with large pores, 1 to 4 {mu}m in size. It was suggested that the increased rate of pore formation along the grain boundaries resulted from a high-temperature embrittlement under irradiation. (orig.).

  16. Polyimide/Glass Composite High-Temperature Insulation

    Science.gov (United States)

    Pater, Ruth H.; Vasquez, Peter; Chatlin, Richard L.; Smith, Donald L.; Skalski, Thomas J.; Johnson, Gary S.; Chu, Sang-Hyon

    2009-01-01

    Lightweight composites of RP46 polyimide and glass fibers have been found to be useful as extraordinarily fire-resistant electrical-insulation materials. RP46 is a polyimide of the polymerization of monomeric reactants (PMR) type, developed by NASA Langley Research Center. RP46 has properties that make it attractive for use in electrical insulation at high temperatures. These properties include high-temperature resistance, low relative permittivity, low dissipation factor, outstanding mechanical properties, and excellent resistance to moisture and chemicals. Moreover, RP46 contains no halogen or other toxic materials and when burned it does not produce toxic fume or gaseous materials. The U. S. Navy has been seeking lightweight, high-temperature-resistant electrical-insulation materials in a program directed toward reducing fire hazards and weights in ship electrical systems. To satisfy the requirements of this program, an electrical-insulation material must withstand a 3-hour gas-flame test at 1,600 F (about 871 C). Prior to the development reported here, RP46 was rated for use at temperatures from -150 to +700 F (about -101 to 371 C), and no polymeric product - not even RP46 - was expected to withstand the Navy 3-hour gas-flame test.

  17. High temperature structural sandwich panels

    Science.gov (United States)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  18. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  19. Motor for High Temperature Applications

    Science.gov (United States)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  20. High strain rate loading of polymeric foams and solid plastics

    Science.gov (United States)

    Dick, Richard D.; Chang, Peter C.; Fourney, William L.

    2000-04-01

    The split-Hopkinson pressure bar (SHPB) provided a technique to determine the high strain rate response for low density foams and solid ABS and polypropylene plastics. These materials are used in the interior safety panels of automobiles and crash test dummies. Because the foams have a very low impedance, polycarbonate bars were used to acquire the strain rate data in the 100 to 1600 l/s range. An aluminum SPHB setup was used to obtain the solid plastics data which covered strain rates of 1000 to 4000 l/s. The curves for peak strain rate versus peak stress for the foams over the test range studied indicates only a slight strain rate dependence. Peak strain rate versus peak stress curves for polypropylene shows a strain rate dependence up to about 1500 l/s. At that rate the solid poly propylene indicates no strain rate dependence. The ABS plastics are strain rate dependent up to 3500 l/s and then are independent at larger strain rates.

  1. Very High Temperature Sound Absorption Coating Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I demonstrated experimentally a very high temperature acoustically absorbing coating for ducted acoustics applications. High temperature survivability at 3500...

  2. Influence of polymeric matrix and fiber on composite materials at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Roussy, L.; Parcelier, M. [Aerospatiale Space and Defense, Les Mureaux (France)

    1995-09-01

    For several years, we have been looking ahead to new concepts of hypersonic planes and launchers with cryotechnic tanks using composite materials for high strength to weight ratios. These structures will be subjected to extremely low temperatures in isothermal or cycling conditions. Within these severe conditions, mechanical properties of composite materials are generally unkown and their behavior not understood. To prepare for this very near future, we have looked at the effect of various parameters at different temperatures (from 400 K down to 20 K) on the mechanical properties of thermoset (cyanate, epoxy, bismaleimide, polyimide) and thermoplastic (PEEK) composite materials. The results enable us to appreciate the complexity and the sensitivity of organic matrices at low temperatures and especially to show up their brittleness. The results of works also show how the different thermal deformations of fiber and matrix induce residual stresses during cooling. These stresses may be critical all the more as the temperature is low and the matrix is brittle. At very low temperatures, relaxation mechanisms and load transfers are strongly reduced which led damages at composite interfaces. These investigations have led to a selection of rules for composite structures design.

  3. Highly protein-resistant coatings and suspension cell culture thereon from amphiphilic block copolymers prepared by RAFT polymerization.

    Science.gov (United States)

    Haraguchi, Kazutoshi; Kubota, Kazuomi; Takada, Tetsuo; Mahara, Saori

    2014-06-09

    Novel amphiphilic block copolymers composed of hydrophobic (poly(2-methoxyethyl acrylate): M) and hydrophilic (poly(N,N-dimethylacrylamide): D) segments were synthesized by living radical polymerization: a reversible addition-fragmentation chain-transfer polymerization. Two types of amphiphilic block copolymers, triblock (MDM) and 4-arm block ((MD)4) copolymers with specific compositions (D/M = (750-1500)/250), were prepared by a versatile one-pot synthesis. These copolymers show good adhesion to various types of substrates (e.g., polystyrene, polycarbonate, polypropylene, Ti, and glass), and the surface coating showed high protein repellency and a low contact angle for water, regardless of the substrate. The two opposing characteristics of high protein repellency and good substrate adhesion were achieved by the combined effects of the molecular architecture of the block copolymers, the high molecular weight, and the characteristics of each segment, that is, low protein adsorption capability of both segments and low glass transition temperature of the hydrophobic segment. Further, a polystyrene dish coated with the MDM block copolymer could be sterilized by γ-ray irradiation and used as a good substrate for a suspension cell culture that exhibits low cell adhesion and good cell growth.

  4. Highly Fluorescent and Photostable Polymeric Nanofibers as Scaffolds for Cell Interfacing and Long-Term Tracking.

    Science.gov (United States)

    Diao, Hua Jia; Wang, Kai; Long, Hong Yan; Wang, Mingfeng; Chew, Sing Yan

    2016-03-09

    Highly fluorescent polymeric nanofibers fabricated via electrospinning of PCL-DPP-PCL (photostable polycaprolactones-di(thiophene-2-yl)-diketopyrrolopyrrole-photostable polycaprolactones) and commercial PCL mixture show superior photostability and cytocompatibility for long-term tracking of cell-substrate interaction. As a proof of concept, these PCL-DPP-PCL nanofibers enable clear visualization of intricate cell-substrate interactions such as oligodendrocyte myelination.

  5. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    NARCIS (Netherlands)

    Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.

    2011-01-01

    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be optim

  6. The Doping Effect on Conductivity and Glass Transition Temperature of Solid Polymeric Electrolyte Based on Polyvinylchloride (pvc)

    Science.gov (United States)

    Abd. Rahman, Mohd. Yusri; Mat Salleh, Muhammad; Abu Talib, Ibrahim; Yahaya, Muhamad

    2002-12-01

    Solid electrolyte materials have been widely used in electrochemical devices such as batteries, solar cells and displays. This is because of its advantages over the liquidmaterial.This paper is concerned with the preparation of solid polymeric electrolyte based on polyvinylchloride (PVC) and its conductivity .The effect of percentage by weight of dopant material (LiClO4) on conductivity and glass transition temperature of the electrolyte was studied by using differential scanning calorimeter (DSC) and impedance spectroscopy technique. The electrolyte doped with 4.8%wt LiClO4 exhibits the highest conductivitiy of 7 × 10-6Scm-1 at room temperature but has the lowest glass transition temperature of 36.37°C. The other results are presented in this paper.

  7. Surface modification of ultra high molecular weight polyethylene fibers via the sequential photoinduced graft polymerization

    Science.gov (United States)

    Li, Zhi; Zhang, Wei; Wang, Xinwei; Mai, Yongyi; Zhang, Yumei

    2011-06-01

    In this study, a sequential photoinduced graft polymerization process was proposed to improve the poor interfacial bonding property of ultra high molecular weight polyethylene (UHMWPE) fibers. The polymerization was initiated by dormant semipinacol (SP) groups and carried out in a thin liquid layer. Methacrylic acid (MAA) and acryl amide (AM) were grafted stepwise onto the surface of UHMWPE fibers. Attenuated total reflectance infrared spectroscopy (ATR-IR) and thermo gravimetric analysis (TGA) confirmed the grafting. The analysis result of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) indicated the structure of grafted chains. Scanning electron microscopy (SEM) images and atomic force microscopy (AFM) images revealed the apparent morphology changing, and the grafted layers were observed. Interfacial shear stress (IFSS) test of the modified fibers showed an extensively improved interfacial bonding property. The active groups grafted onto the fibers would supply enough anchor points for the chemical bonding with various resins or further reactions.

  8. Surface modification of ultra high molecular weight polyethylene fibers via the sequential photoinduced graft polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Li Zhi; Zhang Wei; Wang Xinwei [Research and Development Center of Shanghai Research Institute of Chemical Industry, 345 YunLing Road (East), Shanghai 200062 (China); Mai Yongyi, E-mail: SRICIshanghai@163.com [Research and Development Center of Shanghai Research Institute of Chemical Industry, 345 YunLing Road (East), Shanghai 200062 (China); Zhang Yumei [Research and Development Center of Shanghai Research Institute of Chemical Industry, 345 YunLing Road (East), Shanghai 200062 (China)

    2011-06-15

    In this study, a sequential photoinduced graft polymerization process was proposed to improve the poor interfacial bonding property of ultra high molecular weight polyethylene (UHMWPE) fibers. The polymerization was initiated by dormant semipinacol (SP) groups and carried out in a thin liquid layer. Methacrylic acid (MAA) and acryl amide (AM) were grafted stepwise onto the surface of UHMWPE fibers. Attenuated total reflectance infrared spectroscopy (ATR-IR) and thermo gravimetric analysis (TGA) confirmed the grafting. The analysis result of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) indicated the structure of grafted chains. Scanning electron microscopy (SEM) images and atomic force microscopy (AFM) images revealed the apparent morphology changing, and the grafted layers were observed. Interfacial shear stress (IFSS) test of the modified fibers showed an extensively improved interfacial bonding property. The active groups grafted onto the fibers would supply enough anchor points for the chemical bonding with various resins or further reactions.

  9. Passivation of high temperature superconductors

    Science.gov (United States)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  10. High-speed organocatalytic polymerization of a renewable methylene butyrolactone by a phosphazene superbase

    KAUST Repository

    Schmitt, Meghan L.

    2014-01-01

    The organic phosphazene superbase, 1-tert-butyl-4,4,4-tris(dimethylamino)- 2,2-bis[tris(dimethylamino)phosphoranylid-enamino]-2λ5, 4λ5-catenadi(phosphazene) (t-Bu-P4), is found to directly initiate high-speed polymerization of the biomass-derived renewable γ-methyl-α-methylene-γ-butyrolactone (MMBL), in contrast to other polymerization systems using t-Bu-P4 which typically require addition of an organic acid or a nucleophile as a co-initiating component. This MMBL polymerization by t-Bu-P4 alone is extremely rapid; even with a low t-Bu-P4 loading of 0.1 mol% or 0.02 mol%, quantitative monomer conversion is achieved in 20 s or 1 min, respectively, affording medium to high molecular weight PMMBL bioplastics in a catalytic fashion. The combined experimental and theoretical/computational studies have yielded mechanisms of chain initiation through abstraction of a proton from a monomer by t-Bu-P 4, essentially barrier-less chain propagation through rapid conjugate addition of the enolate anion stabilized by the nano-size cation [t-Bu-P 4H]+ to the monomer, and chain termination through chain transfer to the monomer which generates a saturated termination chain end and the [t-Bu-P4H]+-stabilized anionic active species that starts a new chain. This journal is © the Partner Organisations 2014.

  11. Molecularly imprinted microspheres prepared by precipitation polymerization at high monomer concentrations

    Directory of Open Access Journals (Sweden)

    Renkecz Tibor

    2014-01-01

    Full Text Available Highly crosslinked polymer microparticles have been prepared by precipitation polymerization using high monomer loadings (≥25 v/v % which generally would lead to bulk monoliths. The microparticle format was achieved by the use of non-solvating diluents either alone or in combination with co-solvents. Two distinct morphologies were observed. Monodisperse smooth microspheres were obtained using a thermodynamically good co-solvent whereas segmented irregular particles were formed with poorer co-solvents. It has been found that during polymerization the forming polymer particles were enriched in the co-solvent and this effect was more pronounced when good co-solvents were used. The type of functional monomer, crosslinker and co-solvent, and the non-solvent/co-solvent ratio were identified as influential parameters on the microparticle morphology. With the proposed methodology molecularly imprinted microparticles have been prepared successfully for three different templates, naproxen, diclofenac and toltrazuril using various functional monomers, crosslinkers and polymerization solvent mixtures.

  12. High Temperature Radio Frequency Loads

    CERN Document Server

    Federmann, S; Grudiev, A; Montesinos, E; Syratchev, I

    2011-01-01

    In the context of energy saving and recovery requirements the design of reliable and robust RF power loads which permit a high outlet temperature and high pressure of the cooling water is desirable. Cooling water arriving at the outlet withmore than 150 ◦C and high pressure has a higher value than water with 50 ◦C under low pressure. Conventional RF power loads containing dielectric and magnetic materials as well as sensitive ceramic windows usually do not permit going much higher than 90 ◦C. Here we present and discuss several design concepts for "metal only" RF high power loads. One concept is the application of magnetic steel corrugated waveguides near cutoff – this concept could find practical use above several GHz. Another solution are resonant structures made of steel to be installed in large waveguides for frequencies of 500 MHz or lower. Similar resonant structures above 100 MHz taking advantage of the rather high losses of normal steel may also be used in coaxial line geometries with large di...

  13. In-situ polymerization of polyaniline on the surface of graphene oxide for high electrochemical capacitance

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xinlu, E-mail: lixinlu@cqu.edu.cn; Zhong, Qineng; Zhang, Xinlin; Li, Tongtao; Huang, Jiamu

    2015-06-01

    Conducting polymer polyaniline (PANI) was in-situ polymerized on the surface of graphene oxide (GO) to form PANI encapsulating GO nanocomposites. The morphology and microstructure were examined by scanning electron microscopy, X-ray diffraction and N{sub 2} absorption/desorption analysis. Electrochemical properties were tested by cyclic voltammetry, galvanostatic charge/discharge cycles and electrochemical impedance spectroscopy. Experimental results showed that ethanol assisted the dispersion of GO in water and facilitated the diffusion of polymer monomers on GO. GO as a support material can provide sufficient reaction sites for the deposition of aniline to form the film-like GO/PANI composites. Capacitive performance illustrated that the in-situ polymerization of PANI on GO was effective in improving the specific capacitance and cycling stability. - Highlights: • GO/PANI nanocomposites were achieved by in-situ polymerization. • PANI was uniformly coated on the surface of GO with addition of ethanol. • GO/PANI show high specific capacitance and cycling stability.

  14. High-Voltage Insulation Organic-Inorganic Nanocomposites by Plasma Polymerization

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2014-01-01

    Full Text Available In organic-inorganic nanocomposites, interfacial regions are primarily influenced by the dispersion uniformity of nanoparticles and the strength of interfacial bonds between the nanoparticles and the polymer matrix. The insulating performance of organic-inorganic dielectric nanocomposites is highly influenced by the characteristics of interfacial regions. In this study, we prepare polyethylene oxide (PEO-like functional layers on silica nanoparticles through plasma polymerization. Epoxy resin/silica nanocomposites are subsequently synthesized with these plasma-polymerized nanoparticles. It is found that plasma at a low power (i.e., 10 W can significantly increase the concentration of C–O bonds on the surface of silica nanoparticles. This plasma polymerized thin layer can not only improve the dispersion uniformity by increasing the hydrophilicity of the nanoparticles, but also provide anchoring sites to enable the formation of covalent bonds between the organic and inorganic phases. Furthermore, electrical tests reveal improved electrical treeing resistance and decreased dielectric constant of the synthesized nanocomposites, while the dielectric loss of the nanocomposites remains unchanged as compared to the pure epoxy resin.

  15. A comparative study to determine strength of autopolymerizing acrylic resin and autopolymerizing composite resin influenced by temperature during polymerization: An In Vitro study.

    Science.gov (United States)

    Chhabra, Anuj; Rudraprasad, I V; Nandeeshwar, D B; Nidhi, C

    2017-01-01

    Temporary coverage of a prepared tooth is an important step during various stages of the fixed dental prosthesis. Provisional restorations should satisfy proper mechanical requirements to resist functional and nonfunctional loads. A few studies are carried out regarding the comparison of the effect of curing environment, air and water, on mechanical properties of autopolymerizing acrylic and composite resin. Hence, the aim of this study was to compare the transverse strength of autopolymerizing acrylic resin and autopolymerizing composite resin as influenced by the temperature of air and water during polymerization. Samples of autopolymerizing acrylic resin and composite resin were prepared by mixing as per manufacturer's instructions and were placed in a preformed stainless steel mold. The mold containing the material was placed under different controlled conditions of water temperature and air at room temperature. Polymerized samples were then tested for transverse strength using an Instron universal testing machine. Alteration of curing condition during polymerization revealed a significant effect on the transverse strength. The transverse strength of acrylic resin specimens cured at 60°C and composite resin specimens cured at 80°C was highest. Polymerizing the resin in cold water at 10°C reduced the mechanical strength. Polymerization of the resin in hot water greatly increased its mechanical properties. The method of placing resin restoration in hot water during polymerization may be useful for improving the mechanical requirements and obtaining long-lasting performance.

  16. Phosphasalen indium complexes showing high rates and isoselectivities in rac-lactide polymerizations

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Dominic; White, Andrew J.P. [Department of Chemistry, Imperial College London (United Kingdom); Forsyth, Craig M. [School of Chemistry, Monash University, Clayton, VIC (Australia); Bown, Mark [CSIRO Manufacturing, Bayview Avenue, Clayton, VIC (Australia); Williams, Charlotte K. [Department of Chemistry, Oxford University (United Kingdom)

    2017-05-02

    Polylactide (PLA) is the leading bioderived polymer produced commercially by the metal-catalyzed ring-opening polymerization of lactide. Control over tacticity to produce stereoblock PLA, from rac-lactide improves thermal properties but is an outstanding challenge. Here, phosphasalen indium catalysts feature high rates (30±3 m{sup -1} min{sup -1}, THF, 298 K), high control, low loadings (0.2 mol %), and isoselectivity (P{sub i}=0.92, THF, 258 K). Furthermore, the phosphasalen indium catalysts do not require any chiral additives. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  18. Faraday imaging at high temperatures

    Science.gov (United States)

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  19. High temperature control rod assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, Russell E. (Solana Beach, CA)

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  20. High temperature autoclave vacuum seals

    Science.gov (United States)

    Hoffman, J. R.; Simpson, W. G.; Walker, H. M.

    1971-01-01

    Aluminum sheet forms effective sealing film at temperatures up to 728 K. Soft aluminum wire rings provide positive seal between foil and platen. For applications at temperatures above aluminum's service temperature, stainless steel is used as film material and copper wire as sealant.

  1. Temperature Dependent Residual Stress Models for Ultra-High-Temperature Ceramics on High Temperature Oxidation

    Science.gov (United States)

    Wang, Ruzhuan; Li, Weiguo

    2016-11-01

    The strength of SiC-depleted layer of ultra-high-temperature ceramics on high temperature oxidation degrades seriously. The research for residual stresses developed within the SiC-depleted layer is important and necessary. In this work, the residual stress evolutions in the SiC-depleted layer and the unoxidized substrate in various stages of oxidation are studied by using the characterization models. The temperature and oxidation time dependent mechanical/thermal properties of each phase in SiC-depleted layer are considered in the models. The study shows that the SiC-depleted layer would suffer from large tensile stresses due to the great temperature changes and the formation of pores on high temperature oxidation. The stresses may lead to the cracking and even the delamination of the oxidation layer.

  2. Temperature Dependent Residual Stress Models for Ultra-High-Temperature Ceramics on High Temperature Oxidation

    Science.gov (United States)

    Wang, Ruzhuan; Li, Weiguo

    2017-08-01

    The strength of SiC-depleted layer of ultra-high-temperature ceramics on high temperature oxidation degrades seriously. The research for residual stresses developed within the SiC-depleted layer is important and necessary. In this work, the residual stress evolutions in the SiC-depleted layer and the unoxidized substrate in various stages of oxidation are studied by using the characterization models. The temperature and oxidation time dependent mechanical/thermal properties of each phase in SiC-depleted layer are considered in the models. The study shows that the SiC-depleted layer would suffer from large tensile stresses due to the great temperature changes and the formation of pores on high temperature oxidation. The stresses may lead to the cracking and even the delamination of the oxidation layer.

  3. Fractional polymerization of a suspended planar bilayer creates a fluid, highly stable membrane for ion channel recordings.

    Science.gov (United States)

    Heitz, Benjamin A; Jones, Ian W; Hall, Henry K; Aspinwall, Craig A; Saavedra, S Scott

    2010-05-26

    Suspended planar lipid membranes (or black lipid membranes (BLMs)) are widely used for studying reconstituted ion channels, although they lack the chemical and mechanical stability needed for incorporation into high-throughput biosensors and biochips. Lipid polymerization enhances BLM stability but is incompatible with ion channel function when membrane fluidity is required. Here, we demonstrate the preparation of a highly stable BLM that retains significant fluidity by using a mixture of polymerizable and nonpolymerizable phospholipids. Alamethicin, a voltage-gated peptide channel for which membrane fluidity is required for activity, was reconstituted into mixed BLMs prepared using bis-dienoyl phosphatidylcholine (bis-DenPC) and diphytanoyl phosphatidylcholine (DPhPC). Polymerization yielded BLMs that retain the fluidity required for alamethicin activity yet are stable for several days as compared to a few hours prior to polymerization. Thus, these polymerized, binary composition BLMs feature both fluidity and long-term stability.

  4. Condensation Polymerization

    Indian Academy of Sciences (India)

    S Ramakrishnan

    2017-04-01

    The very idea that large polymer molecules can indeed existwas hotly debated during the early part of the 20th century.As highlighted by Sivaram in his articles on Carothersand Flory, Staudinger’s macromolecular hypothesis was finallyaccepted, and the study of polymers gained momentumbecause of the remarkable efforts of the these two individualswho laid down the foundations concerning the processes thatled to the formation of large polymer molecules, and to thosethat led to an understanding of many of their extraordinaryphysical properties. Condensation polymerizations, as thename suggests, utilizes bond-forming reactions that generatea small molecule condensate, which often needs to be continuouslyremoved to facilitate the formation of the polymer. Inthis article, I shall describe some of the essential principles ofcondensation polymerizations or more appropriately calledstep-growth polymerizations; and I will also describe someinteresting extensions that lead to the formation of polymernetworks and highly branched polymers.

  5. Temperature changes under demineralized dentin during polymerization of three resin-based restorative materials using QTH and LED units

    Directory of Open Access Journals (Sweden)

    Sayed-Mostafa Mousavinasab

    2014-08-01

    Full Text Available Objectives Light-curing of resin-based materials (RBMs increases the pulp chamber temperature, with detrimental effects on the vital pulp. This in vitro study compared the temperature rise under demineralized human tooth dentin during light-curing and the degrees of conversion (DCs of three different RBMs using quartz tungsten halogen (QTH and light-emitting diode (LED units (LCUs. Materials and Methods Demineralized and non-demineralized dentin disks were prepared from 120 extracted human mandibular molars. The temperature rise under the dentin disks (n = 12 during the light-curing of three RBMs, i.e. an Ormocer-based composite resin (Ceram. X, Dentsply DeTrey, a low-shrinkage silorane-based composite (Filtek P90, 3M ESPE, and a giomer (Beautifil II, Shofu GmbH, was measured with a K-type thermocouple wire. The DCs of the materials were investigated using Fourier transform infrared spectroscopy. Results The temperature rise under the demineralized dentin disks was higher than that under the non-demineralized dentin disks during the polymerization of all restorative materials (p 0.05. Conclusions Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

  6. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions.

    Science.gov (United States)

    Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of Nα-benzoyl-l-arginine ethyl ester to Nα-benzoyl-l-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas.

  7. High throughput atmospheric pressure plasma-induced graft polymerization for identifying protein-resistant surfaces.

    Science.gov (United States)

    Gu, Minghao; Kilduff, James E; Belfort, Georges

    2012-02-01

    Three critical aspects of searching for and understanding how to find highly resistant surfaces to protein adhesion are addressed here with specific application to synthetic membrane filtration. They include the (i) discovery of a series of previously unreported monomers from a large library of monomers with high protein resistance and subsequent low fouling characteristics for membrane ultrafiltration of protein-containing fluids, (ii) development of a new approach to investigate protein-resistant mechanisms from structure-property relationships, and (iii) adaptation of a new surface modification method, called atmospheric pressure plasma-induced graft polymerization (APP), together with a high throughput platform (HTP), for low cost vacuum-free synthesis of anti-fouling membranes. Several new high-performing chemistries comprising two polyethylene glycol (PEG), two amines and one zwitterionic monomers were identified from a library (44 commercial monomers) of five different classes of monomers as strong protein-resistant monomers. Combining our analysis here, using the Hansen solubility parameters (HSP) approach, and data from the literature, we conclude that strong interactions with water (hydrogen bonding) and surface flexibility are necessary for producing the highest protein resistance. Superior protein-resistant surfaces and subsequent anti-fouling performance was obtained with the HTP-APP as compared with our earlier HTP-photo graft-induced polymerization (PGP).

  8. In situ polymerization of highly dispersed polypyrrole on reduced graphite oxide for dopamine detection.

    Science.gov (United States)

    Qian, Tao; Yu, Chenfei; Wu, Shishan; Shen, Jian

    2013-12-15

    A composite consisting of reduced graphite oxide and highly dispersed polypyrrole nanospheres was synthesized by a straightforward technique, by in situ chemical oxidative polymerization. The novel polypyrrole nanospheres can prevent the aggregation of reduced graphite oxide sheets by electrostatic repulsive interaction, and enhance their electrochemical properties in the nano-molar measurement of dopamine in biological systems with a linear range of 1-8000 nM and a detection limit as low as 0.3 nM. © 2013 Elsevier B.V. All rights reserved.

  9. Highly selective CO{sub 2}-capturing polymeric organic network structures

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Hyung Joon; Choi, Jung Hoon; Lee, Yeob; Choi, Kyung Min; Park, Jung Hyo; Kang, Jeung Ku [Graduate School of EEWS, Department of Materials Science and Engineering, NanoCentury KI, KAIST, 373-1, Guseong Dong, Yuseong Gu, Daejeon (Korea, Republic of)

    2012-02-15

    Polymeric organic network structures are synthesized using (methanetetrayltetra-4,1-phenylene)tetrakisboronic acid and three kinds of halogen-substituted struts that include heterocyclic groups. While the networks have moderate surface areas, they exhibit good capture and uptake capacities for CO{sub 2} and very high selectivity over CH{sub 4} and H{sub 2} at 298 K and under 1 bar gas pressure. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. High-temperature thermocouples and related methods

    Science.gov (United States)

    Rempe, Joy L.; Knudson, Darrell L.; Condie, Keith G.; Wilkins, S. Curt

    2011-01-18

    A high-temperature thermocouple and methods for fabricating a thermocouple capable of long-term operation in high-temperature, hostile environments without significant signal degradation or shortened thermocouple lifetime due to heat induced brittleness.

  11. PMR Resin Compositions For High Temperatures

    Science.gov (United States)

    Vannucci, Raymond D.

    1989-01-01

    Report describes experiments to identify polymer matrix resins suitable for making graphite-fiber laminates used at 700 degree F (371 degree C) in such applications as aircraft engines to achieve higher thrust-to-weight ratios. Two particular high-molecular-weight formulations of PMR (polymerization of monomer reactants) resins most promising. PMR compositions of higher FMW exhibit enhanced thermo-oxidative stability. Formation of high-quality laminates with these compositions requires use of curing pressures higher than those suitable for compositions of lower FMW.

  12. High Temperature Superconducting Underground Cable

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, Roger, A.

    2010-02-28

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the world’s first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  13. High temperature suppression of dioxins.

    Science.gov (United States)

    Zhan, Ming-Xiu; Chen, Tong; Fu, Jian-Ying; Lin, Xiao-Qing; Lu, Sheng-Yong; Li, Xiao-Dong; Yan, Jian-Hua; Buekens, Alfons

    2016-03-01

    Combined Sulphur-Nitrogen inhibitors, such as sewage sludge decomposition gases (SDG), thiourea and amidosulphonic acid have been observed to suppress the de novo synthesis of dioxins effectively. In this study, the inhibition of PCDD/Fs formation from model fly ash was investigated at unusually high temperatures (650 °C and 850 °C), well above the usual range of de novo tests (250-400 °C). At 650 °C it was found that SDG evolving from dried sewage sludge could suppress the formation of 2,3,7,8-substituted PCDD/Fs with high efficiency (90%), both in weight units and in I-TEQ units. Additionally, at 850 °C, three kinds of sulphur-amine or sulphur-ammonium compounds were tested to inhibit dioxins formation during laboratory-scale tests, simulating municipal solid waste incineration. The suppression efficiencies of PCDD/Fs formed through homogeneous gas phase reactions were all above 85% when 3 wt. % of thiourea (98.7%), aminosulphonic acid (96.0%) or ammonium thiosulphate (87.3%) was added. Differences in the ratio of PCDFs/PCDDs, in weight average chlorination level and in the congener distribution of the 17 toxic PCDD/Fs indicated that the three inhibitors tested followed distinct suppression pathways, possibly in relation to their different functional groups of nitrogen. Furthermore, thiourea reduced the (weight) average chlorinated level. In addition, the thermal decomposition of TUA was studied by means of thermogravimetry-fourier transform infrared spectroscopy (TG-FTIR) and the presence of SO2, SO3, NH3 and nitriles (N≡C bonds) was shown in the decomposition gases; these gaseous inhibitors might be the primary dioxins suppressants.

  14. High temperature power electronics for space

    Science.gov (United States)

    Hammoud, Ahmad N.; Baumann, Eric D.; Myers, Ira T.; Overton, Eric

    1991-01-01

    A high temperature electronics program at NASA Lewis Research Center focuses on dielectric and insulating materials research, development and testing of high temperature power components, and integration of the developed components and devices into a demonstrable 200 C power system, such as inverter. An overview of the program and a description of the in-house high temperature facilities along with experimental data obtained on high temperature materials are presented.

  15. Structure - property relations of high-temperature composite polymer matrices

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, R.J.; Jurek, R.J.; Larive, D.E. [Michigan Molecular Institute, Midland, MI (United States); Tung, C.M. [Northrop Corp., Hawthorne, CA (United States); Donnellan, T. [Naval Air Development Center, Warminster, PA (United States)

    1993-12-31

    The structure-deformation-failure mode-mechanical property relations of high-temperature thermoplastic polyimide and thermoset bismaleimide (BMI) polymeric matrices and their composites will be discussed. In the case of polyimides, the effects of test temperature, thermal history, strain rate, type of filler, and filler volume fraction on structure - property relations will be discussed. For BMIs we report systematic Fourier transform infrared spectroscopy and differential scanning calorimetry studies of the cure reactions as a function of chemical composition and time - temperature cure conditions and then describe the resultant cross-linked network structure based on our understanding of the cure reactions. The optimization of the BMI matrix toughness will be considered in terms of network structure and process-induced matrix microcracking. We also describe optimization of composite prepreg, lamination and postcure conditions based on cure kinetics, and their relationship to the BMI viscosity-time-temperature profiles. The critical processing-performance limitations of high-temperature polymer matrices will be critically discussed, and toughening approaches to address these limitations, such as toughness over a wide temperature range, will be presented. 7 refs., 2 figs., 1 tab.

  16. Injection molding micro patterns with high aspect ratio using a polymeric flexible stamper

    Directory of Open Access Journals (Sweden)

    2011-11-01

    Full Text Available Poor filling occurs during the injection molding process of micro- or nano- scale patterns mainly because the hot polymer melt rapidly cools and its skin quickly solidifies upon contact with the mold surface. In this study, it is proposed to use Polyethylene terephthalate (PET film coated with patterned polyurethane acrylate (PUA as an effective thermal barrier. It can significantly hinder heat transfer into the mold during the molding process and thus may keep the melt viscosity low for longer duration. As a result, the replication would be improved not only during the filling phase but also during the packing phase. In order to verify the validity of the use of polymeric stamper, the melt-film interface temperature was evaluated by numerical simulation. Experimental results indicated that patterns possessing widths within the range of one to tens of micrometers and a height of approximately 10 µm were successfully filled and demolded.

  17. High Temperature Chemistry at NASA: Hot Topics

    Science.gov (United States)

    Jacobson, Nathan S.

    2014-01-01

    High Temperature issues in aircraft engines Hot section: Ni and Co based Superalloys Oxidation and Corrosion (Durability) at high temperatures. Thermal protection system (TPS) and RCC (Reinforced Carbon-Carbon) on the Space Shuttle Orbiter. High temperatures in other worlds: Planets close to their stars.

  18. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  19. Polymerization of liquid propylene with a 4th generation Ziegler-Natta catalyst-influence of temperature, hydrogen and monomer concentration and prepolymerization method on polymerization kinetics

    NARCIS (Netherlands)

    Pater, Jochem T.M.; Weickert, Günter; Swaaij, van Wim P.M.

    2002-01-01

    In a batch-wise operated autoclave reactor, liquid propylene was polymerized using a 4th generation, TiCl4/MgCl2/phthalate ester-AlEt3-R2Si(OMe)2, Ziegler-Natta catalyst system. By using a calorimetric principle it was possible to measure full reaction rate versus time curves for obtaining data on p

  20. Silver Nanoparticle-Deposited Boron Nitride Nanosheets as Fillers for Polymeric Composites with High Thermal Conductivity.

    Science.gov (United States)

    Wang, Fangfang; Zeng, Xiaoliang; Yao, Yimin; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping

    2016-01-19

    Polymer composites with high thermal conductivity have recently attracted much attention, along with the rapid development of the electronic devices toward higher speed and performance. However, a common method to enhance polymer thermal conductivity through an addition of high thermally conductive fillers usually cannot provide an expected value, especially for composites requiring electrical insulation. Here, we show that polymeric composites with silver nanoparticle-deposited boron nitride nanosheets as fillers could effectively enhance the thermal conductivity of polymer, thanks to the bridging connections of silver nanoparticles among boron nitride nanosheets. The thermal conductivity of the composite is significantly increased from 1.63 W/m-K for the composite filled with the silver nanoparticle-deposited boron nitride nanosheets to 3.06 W/m-K at the boron nitride nanosheets loading of 25.1 vol %. In addition, the electrically insulating properties of the composite are well preserved. Fitting the measured thermal conductivity of epoxy composite with one physical model indicates that the composite with silver nanoparticle-deposited boron nitride nanosheets outperforms the one with boron nitride nanosheets, owning to the lower thermal contact resistance among boron nitride nanosheets' interfaces. The finding sheds new light on enhancement of thermal conductivity of the polymeric composites which concurrently require the electrical insulation.

  1. HIGH IMMOBILIZATION OF ANTIBACTERIAL MOIETIES ONTO MONODISPERSE MICROSPHERES BY DISPERSION POLYMERIZATION USING BICATIONIC VIOLOGEN SURFMER

    Institute of Scientific and Technical Information of China (English)

    Sheng-liu Wang; Xiao-fang Yang; Lian-ying Liu; Wan-tai Yang

    2012-01-01

    In order to achieve monodisperse particles with high content of antibacterial groups covalently bonded on surface,a bicationic viologen,N-hexyl-N'-(4-vinylbenzyl)-4,4'-bipyridinium bromide chloride (HVV) was devised as a surfmer in dispersion polymerization of styrene (St) using a mixture of methanol (or ethylene glycol) and water as media.Effects of content of HVV,its addition profile and composition of reaction media on particles size and incorporation of HVV moieties were mainly investigated.The attachment of silver and gold nanoparticles on particle surface under UV irradiation ascertained the surface-bonded HVV segments.SEM,TEM observations and XPS,zata potential measurements indicated that increase of initial HVV contents and addition of HVV (when polymerization had been performed for 3 h) led to grown particles and enhanced immobilization of HVV moieties.Using a mixture of ethylene glycol and water as reaction media,small particles (520-142 nm) with highly attached HVV moieties were prepared.Furthermore,antibacterial efficacy of the resultant particles against S.aureus was assayed,and particles with more HVV moieties anchored on surface demonstrated greater efficiency of antibacterial activity.

  2. Viscosity modification of high-oleic sunflower oil with polymeric additives for the design of new biolubricant formulations.

    Science.gov (United States)

    Quinchia, L A; Delgado, M A; Valencia, C; Franco, J M; Gallegos, C

    2009-03-15

    Although most common lubricants contain mineral or synthetic oils as basestocks, new environmental regulations are demanding environmentally friendly lubricants. In this sense, vegetable oils represent promising alternatives to mineral-based lubricants because of their high biodegradability, good lubricity, and low volatility. However, their poor thermooxidative stability and the small range of viscosity represent a clear disadvantage to be used as suitable biolubricants. The main objective of this work was to develop new environmentally friendly lubricant formulations with improved kinematic viscosity values and viscosity thermal susceptibility. With this aim, a high-oleic sunflower oil (HOSO) was blended with polymeric additives, such as ethylene vinyl acetate (EVA) and styrene-butadiene-styrene (SBS) copolymers, at different concentrations (0.5-5% w/w). Dynamic viscosity and density measurements were performed in a rotational rheometer and capillary densimeter, respectively, in a temperature range between 25 and 120 degrees C. An Arrhenius-like equation fits the evolution of viscosity with temperature fairly well. Both EVA and SBS copolymers may be satisfactorily used as additives to increase the viscosity of HOSO, thus improving the low viscosity values of this oil. HOSO viscosity increases with polymer concentration. Specifically, EVA/HOSO blends exhibit higher viscosity values, which are needed for applications such as lubrication of bearings and four-stroke engines. On the other hand, viscositythermal susceptibility of HOSO samples increases with EVA or SBS concentration.

  3. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    Science.gov (United States)

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively.

  4. Structural analysis of advanced polymeric foams by means of high resolution X-ray computed tomography

    Science.gov (United States)

    Nacucchi, M.; De Pascalis, F.; Scatto, M.; Capodieci, L.; Albertoni, R.

    2016-06-01

    Advanced polymeric foams with enhanced thermal insulation and mechanical properties are used in a wide range of industrial applications. The properties of a foam strongly depend upon its cell structure. Traditionally, their microstructure has been studied using 2D imaging systems based on optical or electron microscopy, with the obvious disadvantage that only the surface of the sample can be analysed. To overcome this shortcoming, the adoption of X-ray micro-tomography imaging is here suggested to allow for a complete 3D, non-destructive analysis of advanced polymeric foams. Unlike metallic foams, the resolution of the reconstructed structural features is hampered by the low contrast in the images due to weak X-ray absorption in the polymer. In this work an advanced methodology based on high-resolution and low-contrast techniques is used to perform quantitative analyses on both closed and open cells foams. Local structural features of individual cells such as equivalent diameter, sphericity, anisotropy and orientation are statistically evaluated. In addition, thickness and length of the struts are determined, underlining the key role played by the achieved resolution. In perspective, the quantitative description of these structural features will be used to evaluate the results of in situ mechanical and thermal test on foam samples.

  5. Thermodynamics of High Temperature Plasmas

    Directory of Open Access Journals (Sweden)

    Ettore Minardi

    2009-03-01

    Full Text Available In this work we discuss how and to what extent the thermodynamic concepts and the thermodynamic formalism can be extended to the description of high temperature states of the plasma not necessarily associated with a Boltzmann distribution and with thermal equilibrium.The discussion is based on the “magnetic or electrostatic entropy concept”, an interpretative and predictive tool based on probability and information, defined in a suitably coarse-grained possibility space of all current density or of all electric charge density distributions under testable constraints, and whose variation properties are proven to be related under certain conditions to the equilibrium and the stability of the system. In the case of magnetic equilibrium the potentiality of the magnetic entropy concept is illustrated by comparing the predictions of the current density and pressure profiles with the observations in different tokamak machines and different tokamak regimes, as well as by showing how the equilibrium and the stability in devices as different as the reversed field pinch or the magnetic well are described by the variation properties of the same entropy functional applied to the different situations. In fact it emerges that the maximum of the entropy can be seen in these different cases as an optimization constraint for the minimum of the magnetic energy. The application of the entropy concept to the electrostatic processes shows in particular that the so-called reactive instabilities (non-dissipative, non-resonant instabilities with a marginal point admit a neighboring state with higher entropy and are therefore of special relevance from the point of view of the physical evolution of the system. In this case the thermodynamic formalism allows the introduction of the concept of “thermodynamic fluctuations” of the macroscopic charge density and provides a method for the calculation of the “thermodynamic” fluctuation levels both on the stable as

  6. Influence of calcination temperature on the zirconia microstructure synthesized by complex polymerization method (CPM): a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Santos, R.L.P.; Mota, F.V.; Nascimento, R.M.; Henriques, B.P.; Silva, F.S.; Assis, R. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2016-07-01

    Full text: The aim of this study was to accomplish a previous characterization of the zirconia synthesized by Complex Polymerization Method (CPM) using yttria as stabilizing agent and different calcination temperatures. The powders were crystallized at 800, 900 and 1000 °C for 2h. The structural evolution Y-TZP powders were characterized by X-Ray Diffraction (XRD) and Micro-Raman Spectroscopy. The thermal properties of the calcined pre-pyrolyzed (350 °C for 4 h), samples were investigated by simultaneous thermo analysis (TGA/DTA). After heat treatment the phase Y-TZP was obtained of a single-phase, with absence of the deleterious phases. The results show that average crystallite size of the powder synthesized with 3% of Yttria dopant, increased from 11.5 to 27.9 nm when the calcination temperature increased from 800 to 1000 °C. This behavior was observed for all specimens independent of the Yttria content. The micro-Raman indicate the presence of the tetragonal phase for all samples independent of the calcination temperature employed. (author)

  7. Synthesis of New Silicon-linked Lanthanocene Complexes and Their High Catalytic Activity for Methyl Methacrylate Polymerization with Nanometric Sodium Hydride as Co-catalyst

    Institute of Scientific and Technical Information of China (English)

    谢小敏; 黄吉玲

    2005-01-01

    The synthesis and characterization of four new silicon-linked lanthanocene complexes with pendant phenyl groups on cyclopentadiene were reported. Based on the data of elemental analyses, MS and IR, the complexes were presumed to be unsolvated and dimeric complexes [Me2Si(C5H3CMe2C6H5)2LnC1]2 [Ln=Er (1), Gd (2), Sm (3), Dy (4)]. In conjunction with AlEt3 or sodium hydride as the co-catalyst, these complexes could efficiently catalyze the polymerization of methyl methacrylate (MMA). When the nanometric sodium hydride was used as a co-catalyst, the complexes were highly effective for the polymerization of MMA. At low temperature and in short time, in [MeESi(C5H3CMe2C6H5)2LnC1]2/NaH (nanometric) system, the polymer was obtained in more than 80% yield and the molecular weight was greater than 105. The activity reached that of organolanthanide hydride as a single-component catalyst. In ]MeESi(C5H3CMe2C6H5)2ErC1]2/Nail (nanometric) system, the effects of the molar ratio of MMA/catalyst and catalyst/co-catalyst, and the temperature on polymerization were studied.

  8. High temperature superconducting fault current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Hinsdale, IL)

    1997-01-01

    A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

  9. Structural effect of lignans and sesamol on polymerization of soybean oil at frying temperature

    Science.gov (United States)

    Antipolymerization activities of lignans including nordihydroguaiaretic acid, (+)-pinoresinol, (-)-secoisolariciresinol, enterodiol, two sesame lignans (sesamol, sesamin), and four model compounds were investigated for soybean oil at frying temperature (180 °C). The heated samples were analyzed by G...

  10. Effect of temperature and -irradiation on gas permeability for polymeric membrane

    Indian Academy of Sciences (India)

    Vaibhav Kulshrestha; K Awasthi; N K Acharya; M Singh; Y K Vijay

    2005-12-01

    In the present study the polyethersulphone (PES) membranes of thickness (35 ± 2) m were prepared by solution cast method. The permeability of these membranes was calculated by varying the temperature and by irradiation of ions. For the variation of temperature, the gas permeation cell was dipped in a constant temperature water bath in the temperature range from 303–373 K, which is well below the glass transition temperature (498 K). The permeability of H2 and CO2 increased with increasing temperature. The PES membrane was exposed by -source (${}_{95}$Am$^{241}$) of strength (1 Ci) in vacuum of the order of 10-6 torr, with fluence 2.7 × 107 ions/cm2. The permeability of H2 and CO2 has been observed for irradiated membrane with increasing etching time. The permeability increases with increasing etching time for both gases. There was a sudden change in permeability for both the gases when observed at 18 min etching. At this stage the tracks are visible with optical instrument, which confirms that the pores are generated. Most of pores seen in the micrograph are circular cross-section ones.

  11. (Krauss) at constant high temperatures

    African Journals Online (AJOL)

    the various physical and chemical factors that may affect freshwater snails. However ... order to assess the effect of temperature on the organism, it is essential to ..... of snails by parasites is of cardinal importance to shed light on the population ...

  12. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Guihua, E-mail: guihuaruan@hotmail.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China); Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Du, Fuyou, E-mail: dufu2005@126.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China)

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

  13. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  14. Accurate fluorescent polymeric thermometers containing an ionic component.

    Science.gov (United States)

    Gota, Chie; Uchiyama, Seiichi; Ohwada, Tomohiko

    2007-02-01

    Fluorescent polymeric thermometers consisting of only N-alkylacrylamide and fluorescent components show rather low temperature resolution in their functional ranges (ca. 15-50 degrees C) because of the occurrence of intermolecular aggregation, which causes hysteresis in their fluorescence response to changes in temperature. By adding an ionic component to prevent such intermolecular aggregation, we obtained four fluorescent polymeric thermometers that offer high temperature resolution (<0.2 degrees C). Each new fluorescent polymeric thermometer covered the temperature range, 9-33 degrees C, 30-51 degrees C, 49-66 degrees C or 4-38 degrees C.

  15. Study of the effect of external heating and internal temperature build-up during polymerization on the morphology of porous polymethacrylate adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Chan Yi, E-mail: vicchanyiwei@hotmail.com; Ongkudon, Clarence M., E-mail: clarence@ums.edu.my; Kansil, Tamar, E-mail: tamarkansil87@gmail.com [Biotechnology Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah (Malaysia)

    2015-07-22

    Modern day synthesis protocols of methacrylate monolithic polymer adsorbent are based on existing polymerization blueprint without a thorough understanding of the dynamics of pore structure and formation. This has resulted in unproductiveness of polymer adsorbent consequently affecting purity and recovery of final product, productivity, retention time and cost effectiveness of the whole process. The problems magnified in monolith scaling-up where internal heat buildup resulting from external heating and high exothermic polymerization reaction was reflected in cracking of the adsorbent. We believe that through careful and precise control of the polymerization kinetics and parameters, it is possible to prepare macroporous methacrylate monolithic adsorbents with controlled pore structures despite being carried out in an unstirred mould. This research involved the study of the effect of scaling-up on pore morphology of monolith, in other words, porous polymethacrylate adsorbents that were prepared via bulk free radical polymerization process by imaging the porous morphology of polymethacrylate with scanning electron microscope.

  16. A kinetic approach to modeling the manufacture of high density strucutral foam: Foaming and polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Mondy, Lisa Ann [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Noble, David R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Brunini, Victor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Roberts, Christine Cardinal [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Long, Kevin Nicholas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Soehnel, Melissa Marie [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Celina, Mathias C. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Wyatt, Nicholas B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Thompson, Kyle R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Tinsley, James

    2015-09-01

    We are studying PMDI polyurethane with a fast catalyst, such that filling and polymerization occur simultaneously. The foam is over-packed to tw ice or more of its free rise density to reach the density of interest. Our approach is to co mbine model development closely with experiments to discover new physics, to parameterize models and to validate the models once they have been developed. The model must be able to repres ent the expansion, filling, curing, and final foam properties. PMDI is chemically blown foam, wh ere carbon dioxide is pr oduced via the reaction of water and isocyanate. The isocyanate also re acts with polyol in a competing reaction, which produces the polymer. A new kinetic model is developed and implemented, which follows a simplified mathematical formalism that decouple s these two reactions. The model predicts the polymerization reaction via condensation chemis try, where vitrification and glass transition temperature evolution must be included to correctly predict this quantity. The foam gas generation kinetics are determined by tracking the molar concentration of both water and carbon dioxide. Understanding the therma l history and loads on the foam due to exothermicity and oven heating is very important to the results, since the kinetics and ma terial properties are all very sensitive to temperature. The conservation eq uations, including the e quations of motion, an energy balance, and thr ee rate equations are solved via a stabilized finite element method. We assume generalized-Newtonian rheology that is dependent on the cure, gas fraction, and temperature. The conservation equations are comb ined with a level set method to determine the location of the free surface over time. Results from the model are compared to experimental flow visualization data and post-te st CT data for the density. Seve ral geometries are investigated including a mock encapsulation part, two configur ations of a mock stru ctural part, and a bar geometry to

  17. Isolation and characterization of inulin with a high degree of polymerization from roots of Stevia rebaudiana (Bert.) Bertoni.

    Science.gov (United States)

    Lopes, Sheila M S; Krausová, Gabriela; Rada, Vojtěch; Gonçalves, José E; Gonçalves, Regina A C; de Oliveira, Arildo J B

    2015-06-26

    The polysaccharide inulin has great importance in the food and pharmaceutical industries. The degree of polymerization (DP) of inulin influences important properties, such as, solubility, thermal stability, sweetness power and prebiotic activity. Molecules with a high degree of polymerization are obtained through physical techniques for enrichment of the inulin chains because they are not commonly obtained from plants extract. Gas chromatography/Mass Spectrometry and (1)H Nuclear Magnetic Resonance analysis showed that inulin from Stevia rebaudiana roots has a degree of polymerization (DPn 28) higher than the value of DPn 12-15 for inulins from other plant species. Furthermore, the methodology of freeze/thaw to enrich the chains allowed us to increase the DP, similarly to other methodologies used for the enrichment of inulin chains. The prebiotic assays confirm that inulin from S. rebaudiana has a high DP. The combined use of these molecules with low degree of polymerization fructans seems to be advantageous to prolong the prebiotic effect in the colon. Our results suggest that S. rebaudiana roots are a promising source of high degree polymerization inulins.

  18. Application of polymeric macroporous supports for temperature-responsive chromatography of pharmaceuticals.

    Science.gov (United States)

    Lamprou, Alexandros; Gavriilidou, Agni-Faviola-Mika; Storti, Giuseppe; Soos, Miroslav; Morbidelli, Massimo

    2015-08-14

    A macroporous particulate support prepared previously by reactive gelation under shear and functionalized with poly(N-isopropylacrylamide), PNIPAM, brushes of variable length is applied for temperature-responsive chromatography, whereby temperature modulates hydrophobic interactions. Several different analytes, including small pharmaceuticals, peptides, proteins and monoclonal antibodies are employed. Contrary to the most commonly observed behavior in conventional chromatography, increasing retention is observed at elevated temperatures. Peak broadening is quantified using the peak standard deviation, which depends on both the polymer chain conformation and analyte adsorptivity. The favorable effect of grafted polymer thickness on retention becomes progressively less pronounced for thicker grafted PNIPAM layers. The effect of eluent composition on solute-sorbent interactions was investigated by introducing NaCl, methanol, dioxane and by varying the pH. Salt or organic solvent addition affects apart from the analytes solution properties, the hydrophobicity of the stationary phase itself. Frontal analyses performed at different temperatures to determine dynamic binding capacities, indicate small mass transfer resistances imposed by this novel packing material. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    and oxygen with a new type of alkaline electrolysis cell at high temperatures and pressures. To perform measurements under high pressure and at elevated temperatures it was necessary to build a measurement system around an autoclave which could stand high temperatures up to 250 °C and pressures up to 200 bar...... as well as extremely caustic environments. Based on a literature study to identify resistant materials for these conditions, Inconel 600 was selected among the metals which are available for autoclave construction. An initial single atmosphere high temperature and pressure measurement setup was build...... comprising this autoclave. A second high temperature and pressure measurement setup was build based on experiences from the first setup in order to perform automatized measurements. The conductivity of aqueous KOH at elevated temperatures and high concentrations was investigated using the van der Pauw method...

  20. High Molecular Weight Thermally Stable Poly (Sodium Methacrylate / Magnetites Nanocomposites Via Emulsion Polymerization

    Directory of Open Access Journals (Sweden)

    Rasha A. El-Ghazawya,

    2014-04-01

    Full Text Available Core/shell type magnetite nanocomposites (MN were synthesized using sodium methacrylate (NMA monomer. Functionalized and bare magnetite nanoparticles were prepared by conventional co-precipitation method giving particles with 3-10 nm in diameter. Microemulsion polymerization was used for constructing core/shell structure with magnetite nanoparticles as core and poly (sodium methacrylate as shell. Chemical structure and morphology of the synthesized PNMA/magnetite nanocomposites were investigated using FTIR and TEM, respectively. The synthesized nanocomposites show effective encapsulation of different treated magnetite nanoparticles in the polymer matrix and exhibited good thermal stability. Such magnetite nanocomposites with high molecular weight and thermal stability have potential application in enhanced oil recovery application.

  1. Refractometric sensor utilizing a vertically coupled polymeric microdisk resonator incorporating a high refractive index overlay.

    Science.gov (United States)

    Kim, Gun-Duk; Son, Geun-Sik; Lee, Hak-Soon; Kim, Ki-Do; Lee, Sang-Shin

    2009-04-01

    A refractometric sensor resorting to a vertically coupled polymeric microdisk resonator was demonstrated, estimating the refractive index (RI) of an analyte by monitoring the resonant wavelength shift in its transfer characteristics. The disk resonator was especially overlaid with a high RI TiO2 film, thereby reinforcing the interaction of the evanescent field of its guided mode with the analyte. The sensitivity of the sensor was theoretically and experimentally confirmed to be enhanced by adjusting the overlay thickness. The fabricated sensor provided the maximum sensitivity of approximately 294 nm/RIU (refractive index unit) with the 40-nm-thick overlay, which is equivalent to an improvement of 150% compared with the case without the overlay.

  2. Hydrophobic and high adhesive polyaniline layer of rectangular microtubes fabricated by a modified interfacial polymerization

    Science.gov (United States)

    Zhou, Chuanqiang; Gong, Xiangxiang; Qu, Yun; Han, Jie

    2016-08-01

    A modified interfacial polymerization of aniline is developed to fabricate hydrophobic and adhesive polyaniline (PANI) layer of rectangular microtubes on the glass substrate. The modified method uses pentanol as an organic medium to dissolve aniline monomer, with the water film of oxidant and surfactant on the glass substrate as water phase. The effects of some synthetic parameters (such as monomer concentration, alcohol molecular structure and surfactant type) on the morphology of PANI layer are studied for better understanding the fabrication of PANI nanostructures on the film. The alcohol molecular structure plays key role for the supermolecular assembly of PANI chains into nanostructures, while the surfactant may direct the array and deposition of these nanostructures on the glass substrate. The formation reason of PANI rectangular sub-microtubes is roughly interpreted according to our previous works. Wettability experiment indicates that the as-prepared PANI layer exhibits excellent hydrophobicity and high adhesive properties to water drop.

  3. Synthesis of High cis-Polybutadiene in Styrene Solution with Neodymium-Based Catalysts: Towards the Preparation of HIPS and ABS via In Situ Bulk Polymerization

    Directory of Open Access Journals (Sweden)

    Ramón Díaz de León

    2016-01-01

    Full Text Available In a first step, 1,3-butadiene was selectively polymerized at 60°C in styrene as solvent using NdV3/DIBAH/EASC as the catalyst system. The catalyst system activation process, the addition order of monomers and catalyst components, and the molar ratios [Al]/[Nd] and [Cl]/[Nd] were studied. The catalyst system allowed the selective 1,3-butadiene polymerization, reaching conversions between 57.5 and 88.1% with low polystyrene contents in the order of 6.3 to 15.4%. Molecular weights ranging from 39,000 to 150,000 g/mol were obtained, while cis-1,4 content was found in the interval of 94.4 to 96.4%. On the other hand, the glass transition temperatures of synthesized materials were established in the range of −101.9 to −107.4°C, explained by the presence of polystyrene segments in the polybutadiene chains; in the same sense, the polybutadienes did not show the typical melting endotherm of high cis-polybutadienes. In a second step, the resulting styrene/high cis-1,4 polybutadiene solutions were used to synthesize ABS (adding a fraction of acrylonitrile monomer and HIPS via in situ bulk polymerizations and the results were discussed in terms of morphological development, molecular parameters, dynamical mechanical behavior, and mechanical properties.

  4. High-temperature protective coatings on superalloys

    Institute of Scientific and Technical Information of China (English)

    刘培生; 梁开明; 周宏余

    2002-01-01

    Protective coatings are essential for superalloys to serve as blades of gas turb ines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high-temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high-temperature oxidation law of aluminide coatings.

  5. Domestic Polymerization Inhibitor BL-628B Used in High-Pressure Depropanizer of Ethylene Unit Commands an International Leading Position

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The high-pressure depropanizer of the 180 kt/a ethylene unit at the SINOPEC's Zhongyuan Petrochemical Limited Liability Company has been smoothly operating for three years since the adoption of the polymerization inhibitor BL-62B manufactured by the Beijing Sparrow Science and Technology Company to achieve first in China the target on a threeyear long-cycle,overloaded and stable operation.The large ethylene unit at PetroChina's Lanzhou Petrochemical Company will shortly apply this polymerization inhibitor to substitute for the imported additive,symbolizing the indigenous mature technology for inhibiting polymerization in the HP depropanizer by means of the multifunctional additive under high load with the product quality reaching the internationally advanced level.

  6. High Temperature Heterojunction Bipolar Transistors

    Science.gov (United States)

    1994-04-15

    2700 cmW/V-s at room temperature, a far higher value than ever found for GaN or AlGaN. Thus a GaN/ InGaN HEMT would be analogous to InP/InGaAs HEMTs...Spire’s ECR plasma source modif led as a crystal growth reactor. 8 The substrate for the film deposition is mounted on a sample holder which is...The three samples from the second growth run were also characterized. One sample was found to have a very even frosty white haze on it. The other

  7. A high temperature fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Sekido, A.; Nakai, M.; Ninomiya, Y.

    1982-12-21

    A solid electrolyte which conducts electricity with heating by oxygen ions and operates at a temperature of 1,000C is used in the element. The cathode, besides the ionic conductivity in oxygen, has an electron conductivity. The anode has electron conductivity. Substances such as Bi203, into which oxides of alkaline earth metals are added, are used for making the cathode. The electrolyte consists of ZrO2 and Y2O3, to which CaO is added. WC, to which an H2 type fuel is fed, serves as the anode. The element has a long service life.

  8. Ultrasonic Sensors for High Temperature Applications

    Science.gov (United States)

    Tittmann, Bernhard; Aslan, Mustafa

    1999-05-01

    Many processes take place under conditions other than ambient, and chief among these is high temperature. Examples of high temperature industrial processes are resin transfer molding, molten metal infiltration and rheocasting of composite metals alloys. The interaction of waves with viscous fluids is an additional complication adding to an already complicated problem of operating a sensor at high temperature for extended periods of time. This report attempts to provide an insight into the current state of the art of sensor techniques for in-situ high temperature monitoring.

  9. Advances in high temperature chemistry 1

    CERN Document Server

    Eyring, Leroy

    2013-01-01

    Advances in High Temperature Chemistry, Volume 1 describes the complexities and special and changing characteristics of high temperature chemistry. After providing a brief definition of high temperature chemistry, this nine-chapter book goes on describing the experiments and calculations of diatomic transition metal molecules, as well as the advances in applied wave mechanics that may contribute to an understanding of the bonding, structure, and spectra of the molecules of high temperature interest. The next chapter provides a summary of gaseous ternary compounds of the alkali metals used in

  10. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR program, TRS Technologies has developed several new dielectrics for high temperature applications including signal conditioning, filtering and energy...

  11. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng

    2013-01-01

    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  12. Alloys developed for high temperature applications

    Science.gov (United States)

    Basuki, Eddy Agus; Prajitno, Djoko Hadi; Muhammad, Fadhli

    2017-01-01

    Alloys used for high temperatures applications require combinations of mechanical strength, microstructural stability and corrosion/oxidation resistance. Nickel base superalloys have been traditionally the prime materials utilized for hot section components of aircraft turbine engines. Nevertheless, due to their limited melting temperatures, alloys based on intermetallic compounds, such as TiAl base alloys, have emerged as high temperature materials and intensively developed with the main aim to replace nickel based superalloys. For applications in steam power plants operated at lower temperatures, ferritic high temperature alloys still attract high attention, and therefore, development of these alloys is in progress. This paper highlights the important metallurgical parameters of high temperature alloys and describes few efforts in the development of Fe-Ni-Al based alloys containing B2-(Fe,Ni)Al precipitates, oxide dispersion strengthening (ODS) ferritic steels and titanium aluminide based alloys include important protection system of aluminide coatings.

  13. Investigations into High Temperature Components and Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  14. High temperature skin friction measurement

    Science.gov (United States)

    Tcheng, Ping; Holmes, Harlan K.; Supplee, Frank H., Jr.

    1989-01-01

    Skin friction measurement in the NASA Langley hypersonic propulsion facility is described. The sensor configuration utilized an existing balance, modified to provide thermal isolation and an increased standoff distance. For test run times of about 20 sec and ambient-air cooling of the test section and balance, the modified balance performed satisfactorily, even when it was subjected to acoustic and structural vibration. The balance is an inertially balanced closed-loop servo system where the current to a moving-coil motor needed to restore or null the output from the position sensor is a measure of the force or skin friction tending to displace the moving element. The accuracy of the sensor is directly affected by the position sensor in the feedback loop, in this case a linear-variable differential transformer which has proven to be influenced by temperature gradients.

  15. Corrosion Resistant Coatings for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  16. Synthesis and Evaluation of Molecularly Imprinted Polymeric Microspheres for Chloramphenicol by Aqueous Suspension Polymerization as a High Performance Liquid Chromatography Stationary Phase

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan [Beijing Forestry Univ., Beijing (China); Lei, Jiandu [Univ., of Science and Technology, Beijing (Korea, Republic of)

    2013-06-15

    Molecularly imprinted microsphere for chloramphenicol (CAP) with high adsorption capacity and excellent selectivity is prepared by aqueous suspension polymerization, in which chloramphenicol is used as template molecule and ethyl acetate as porogen. The CAP-imprinted microspheres are used as high performance liquid chromatography (HPLC) stationary phase and packed into stainless steel column (150 mm Χ 4.6 mm i. d.) for selective separation of chloramphenicol. HPLC analysis suggests that chloramphenicol can be distinguished from not only its structural analogs but also other broad-spectrum antibiotic such as erythromycin and tetracycline. In addition, the binding experiments of CAP-imprinted microspheres are carried out in ethanol/water (1:4, V:V), the results indicate that the maximum apparent static binding capacity of molecularly imprinted microspheres is up to 66.64 mg g{sup -1} according to scatchard model.

  17. Rapid Temperature Swing Adsorption using Polymeric/Supported Amine Hollow Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Chance, Ronald [Georgia Tech Research Corporation, Atlanta, GA (United States); Chen, Grace [Georgia Tech Research Corporation, Atlanta, GA (United States); Dai, Ying [Georgia Tech Research Corporation, Atlanta, GA (United States); Fan, Yanfang [Georgia Tech Research Corporation, Atlanta, GA (United States); Jones, Christopher [Georgia Tech Research Corporation, Atlanta, GA (United States); Kalyanaraman, Jayashree [Georgia Tech Research Corporation, Atlanta, GA (United States); Kawajiri, Yoshiaki [Georgia Tech Research Corporation, Atlanta, GA (United States); Koros, William [Georgia Tech Research Corporation, Atlanta, GA (United States); Lively, Ryan [Georgia Tech Research Corporation, Atlanta, GA (United States); McCool, Benjamin [Georgia Tech Research Corporation, Atlanta, GA (United States); Pang, Simon [Georgia Tech Research Corporation, Atlanta, GA (United States); Realff, Matthew [Georgia Tech Research Corporation, Atlanta, GA (United States); Rezaei, Fateme [Georgia Tech Research Corporation, Atlanta, GA (United States); Searcy, Katherine [Georgia Tech Research Corporation, Atlanta, GA (United States); Sholl, David [Georgia Tech Research Corporation, Atlanta, GA (United States); Subramanian, Swernath [Georgia Tech Research Corporation, Atlanta, GA (United States); Pang, Simon [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2015-03-31

    This project is a bench-scale, post-combustion capture project carried out at Georgia Tech (GT) with support and collaboration with GE, Algenol Biofuels, Southern Company and subcontract to Trimeric Corporation. The focus of the project is to develop a process based on composite amine-functionalized oxide / polymer hollow fibers for use as contactors in a rapid temperature swing adsorption post-combustion carbon dioxide capture process. The hollow fiber morphology allows coupling of efficient heat transfer with effective gas contacting, potentially giving lower parasitic loads on the power plant compared to traditional contacting strategies using solid sorbents.

  18. Methylene-bridged bimetallic α-diimino nickel(II) complexes: synthesis and high efficiency in ethylene polymerization.

    Science.gov (United States)

    Kong, Shaoliang; Song, Kuifeng; Liang, Tongling; Guo, Cun-Yue; Sun, Wen-Hua; Redshaw, Carl

    2013-07-07

    A series of 1,2-bis(arylimino)acenaphthylidenes (L1-L5) and their corresponding 4,4'-methylenebis(1-(2,6-diisopropylphenylimino)-2-(arylimino)acenaphthylene) derivatives (L6-L10) were synthesized and used to form mono-nuclear nickel bromides LnNiBr2 (n = 1-5, Ni1-Ni5) and bi-nuclear nickel halides LnNi2X4 (n = 6-10: X = Br, Ni2-1-Ni2-5; n = 4, X = Cl, Ni2-6). All the organic compounds were fully characterized by FT-IR spectra, NMR measurements and elemental analysis. The nickel complexes were characterized by FT-IR spectra and elemental analysis and the molecular structures of the representative complexes Ni1, Ni2-1 and Ni2-3 were confirmed by single-crystal X-ray diffraction. Upon activation with either Et2AlCl or MAO, all the nickel complex pre-catalysts exhibited high activity toward ethylene polymerization over the temperature range from ambient to 50 °C. In general, the bi-nuclear complexes showed a positive synergetic effect with higher activity than their mono nuclear analogs. The resultant polyethylene possessed higher molecular weight and a high degree of branching.

  19. High-Temperature Passive Power Electronics

    Science.gov (United States)

    1997-01-01

    In many future NASA missions - such as deep-space exploration, the National AeroSpace Plane, minisatellites, integrated engine electronics, and ion or arcjet thrusters - high-power electrical components and systems must operate reliably and efficiently in high-temperature environments. The high-temperature power electronics program at the NASA Lewis Research Center focuses on dielectric and insulating material research, the development and characterization of high-temperature components, and the integration of the developed components into a demonstrable 200 C power system - such as an inverter. NASA Lewis has developed high-temperature power components through collaborative efforts with the Air Force Wright Laboratory, Northrop Grumman, and the University of Wisconsin. Ceramic and film capacitors, molypermalloy powder inductors, and a coaxially wound transformer were designed, developed, and evaluated for high-temperature operation.

  20. Fractionation of polyphenols in hawthorn into polymeric procyanidins, phenolic acids and flavonoids prior to high-performance liquid chromatographic analysis.

    Science.gov (United States)

    Svedström, Ulla; Vuorela, Heikki; Kostiainen, Risto; Laakso, Into; Hiltunen, Raimo

    2006-04-21

    Polymeric procyanidins, phenolic carboxylic acids and flavonoids of hawthorn (Crataegus laevigata) were fractionated prior to HPLC analysis using column chromatography and solid-phase extraction (SPE). The flavonoid fraction also contained (-)-epicatechin. The three groups of phenolics, each with clearly different UV spectra, were examined by means of high-performance liquid chromatography-diode array detection (HPLC-DAD) analysis. The average repeatability of the method (RSD) was in the range of 8-13% for chlorogenic acid, (-)-epicatechin and hyperoside. The polymeric procyanidins of hawthorn flowers consisted mainly of (-)-epicatechin subunits, and their mean degree of polymerization (DP) was 22.2. The HPLC methods developed can be used for the qualitative and quantitative analysis of different phenolic compounds in hawthorn plant material and their extracts.

  1. A Road Towards High Temperature Superconductors

    Science.gov (United States)

    2013-08-01

    AFRL-AFOSR-UK-TR-2013-0040 A Road Towards High Temperature Superconductors Guy Deutscher Tel Aviv University Research... Superconductors 5a. CONTRACT NUMBER FA8655-10-1-3011 5b. GRANT NUMBER Grant 10-3011 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S...issue in trying to make useful high temperature superconductors is obviously to discover superconductivity at higher temperatures. But there is also

  2. High Temperature Rechargeable Battery Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This small business innovation research is intended to develop and proof the concept of a highly efficient, high temperature rechargeable battery for supporting...

  3. Lightweight, High-Temperature Radiator Panels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightweight, high-temperature radiators are needed for future, high-efficiency power conversion systems for Nuclear Electric Propulsion (NEP). Creare has developed...

  4. High Temperature Solid State Lithium Battery Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Reliable energy systems with high energy density capable of operating at high temperatures, pressures and radiation levels are needed for certain NASA missions....

  5. Lightweight, High-Temperature Radiator Panels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightweight, high-temperature radiators are needed for future, high-efficiency power conversion systems for Nuclear Electric Propulsion (NEP). Creare has developed...

  6. Thermal Expansion of Three Closed Cell Polymeric Foams at Cryogenic Temperatures

    Science.gov (United States)

    Stokes, Eric

    2006-01-01

    The Space Shuttle External Tank (ET) contains the liquid H2 fuel and liquid oxygen oxidizer and supplies them under pressure to the three space shuttle main engines (SSME) in the orbiter during lift-off and ascent. The ET thermal protection system consists of sprayed-on foam insulation and pre-molded ablator materials. The closed-cell foams are the external coating on the ET and are responsible for minimizing the amount of moisture that condenses out and freezes on the tank from the humid air in Florida while it is on the pad with cryogenic propellant awaiting launch. This effort was part of the overall drive to understand the behavior of these materials under use-conditions. There are four specially-engineered closed-cell foams used on the tank. The thermal expansion (contraction) of three of the polyurethane and polyisocyanurate foams were measured from -423 F (the temperature of liquid hydrogen) to 125 F under atmospheric conditions and under vacuum. One of them, NCFI 24-124, is a mechanically-applied material and covers the main acreage of the tank, accounting for 77 percent of the total foam used. Another, BX-265, is also a mechanically-applied and hand-sprayed material used on the tank's "closeout" areas. PDL 1034 is a hand-poured foam used for filling odd-shaped cavities in the tank, Measurements were made in triplicate in the three primary material directions in the case of the first two materials and the two primary material directions in the case of the last. Task 1 was developing the techniques for getting a uniform heating rate and minimizing axial and radial thermal gradients in the specimens. Temperature measurements were made at four locations in the specimens during this initial development phase of testing. Major challenges that were overcome include developing techniques for transferring the coolant, liquid helium (-452 F), from its storage container to the test facility with a minimal transfer of heat to the coolant and control of the heating

  7. Ceramic fibres for high temperature insulation

    Energy Technology Data Exchange (ETDEWEB)

    Padgett, G.C.

    1986-03-01

    Traditionally, refractory linings for high temperature plant and furnaces have comprised either brick or some form of concrete. In recent years, energy conservation has encouraged the greater use of high temperature insulation which is also available in either brick or a lightweight concrete. As an alternative, insulation can also be achieved using fibrous products or fibres combining low heat transfer with low heat capacity.

  8. POLYMERIZATION OF OCTAMETHYLCYCLOTETRASILOXANE WITH HEXAMETHYLDISILAZYL-LITHIUM AS INITIATOR

    Institute of Scientific and Technical Information of China (English)

    Zhijie Zhang; Ning Zhou; Cai-hong Xu; Ze-min Xie

    2001-01-01

    This work focused on the anionic polymerization of octamethylcyclotetrasiloxane (D4, D = Me2SiO2/2) initiated by a new kind of initiator hexamethyldisilazyl-lithium (MMPi). 29Si-NMR spectroscopy and gas chromatography (GC) were used to characterize the polymerization products. The process was accelerated by adding a small amount of high activity monomer D3 and by raising the polymerization temperature. At the end of polymerization more than 95% of the monomer was converted to polymer and only a very small amount ofD4 and D5 remained in the polymers.

  9. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.

    Science.gov (United States)

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang

    2013-01-01

    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks.

  10. Plasma micro-nanotextured polymeric micromixer for DNA purification with high efficiency and dynamic range.

    Science.gov (United States)

    Kastania, Athina S; Tsougeni, Katerina; Papadakis, George; Gizeli, Electra; Kokkoris, George; Tserepi, Angeliki; Gogolides, Evangelos

    2016-10-26

    We present a polymeric microfluidic chip capable of purifying DNA through solid phase extraction. It is designed to be used as a module of an integrated Lab-on-chip platform for pathogen detection, but it can also be used as a stand-alone device. The microfluidic channels are oxygen plasma micro-nanotextured, i.e. randomly roughened in the micro-nano scale, a process creating high surface area as well as high density of carboxyl groups (COOH). The COOH groups together with a buffer that contains polyethylene glycol (PEG), NaCl and ethanol are able to bind DNA on the microchannel surface. The chip design incorporates a mixer so that sample and buffer can be efficiently mixed on chip under continuous flow. DNA is subsequently eluted in water. The chip is able to isolate DNA with high recovery efficiency (96± 11%) in an extremely large dynamic range of prepurified Salmonella DNA as well as from Salmonella cell lysates that correspond to a range of 5 to 1.9 × 10(8) cells (0.263 fg to 2 × 500 ng). The chip was evaluated via absorbance measurements, polymerase chain reaction (PCR), and gel electrophoresis.

  11. High quality factor polymeric Fabry-Perot resonators utilizing a polymer waveguide.

    Science.gov (United States)

    Tadayon, Mohammad Amin; Baylor, Martha-Elizabeth; Ashkenazi, Shai

    2014-03-10

    Optical resonators are used in a variety of applications ranging from sensors to lasers and signal routing in high volume communication networks. Achieving a high quality (Q) factor is necessary for higher sensitivity in sensing applications and for narrow linewidth light emission in most lasing applications. In this work, we propose a new approach to achieve a very high Q-factor in polymeric Fabry-Perot resonators by conquering light diffraction inside the optical cavity. This can be achieved by inducing a refractive index feature inside the optical cavity that simply creates a waveguide between the two mirrors. This approach eliminates diffraction loss from the cavity and therefore the Q-factor is only limited by mirror loss and absorption. To demonstrate this claim, a device has been fabricated consisting of two dielectric Bragg reflectors with a 100 μm layer of photosensitive polymer between them. The refractive index of this polymer can be modified utilizing standard photo-lithography processes. The measured finesse of the fabricated device was 692 and the Q-factor was 55000.

  12. Application of High Temperature Superconductors to Accelerators

    CERN Document Server

    Ballarino, A

    2000-01-01

    Since the discovery of high temperature superconductivity, a large effort has been made by the scientific community to investigate this field towards a possible application of the new oxide superconductors to different devices like SMES, magnetic bearings, flywheels energy storage, magnetic shielding, transmission cables, fault current limiters, etc. However, all present day large scale applications using superconductivity in accelerator technology are based on conventional materials operating at liquid helium temperatures. Poor mechanical properties, low critical current density and sensitivity to the magnetic field at high temperature are the key parameters whose improvement is essential for a large scale application of high temperature superconductors to such devices. Current leads, used for transferring currents from the power converters, working at room temperature, into the liquid helium environment, where the magnets are operating, represent an immediate application of the emerging technology of high t...

  13. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    Sanjay Upadhyay; Hem Chandra; Meenakashi Joshi; Deepika P Joshi

    2011-01-01

    The knowledge of elasticity of the minerals is useful for interpreting the structure and composition of the lower mantle and also in seismic studies. The purpose of the present study is to discuss a simple and straightforward method for evaluating thermoelastic properties of minerals at high temperatures. We have extended the Kumar’s formulation by taking into the account the concept of anharmonicity in minerals above the Debye temperature (D). In our present study, we have investigated the thermophysical properties of two minerals (pyrope-rich garnet and MgAl2O4) under high temperatures and calculated the second-order elastic constant () and bulk modulus (T) of the above minerals, in two cases first by taking Anderson–Gruneisen parameter (T) as temperature-independent and then by treating T as temperature-dependent parameter. The results obtained when T is temperature-dependent are in close agreement with experimental data.

  14. Low to high temperature energy conversion system

    Science.gov (United States)

    Miller, C. G. (Inventor)

    1977-01-01

    A method for converting heat energy from low temperature heat sources to higher temperature was developed. It consists of a decomposition chamber in which ammonia is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature energy source. A recombination reaction then takes place which increases the temperature of a fluid significantly. The system is of use for the efficient operation of compact or low capital investment turbine driven electrical generators, or in other applications, to enable chemical reactions that have a critical lower temperature to be used. The system also recovers heat energy from low temperature heat sources, such as solar collectors or geothermal sources, and converts it to high temperatures.

  15. Sandia_HighTemperatureComponentEvaluation_2015

    Energy Technology Data Exchange (ETDEWEB)

    Cashion, Avery T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    The objective of this project is to perform independent evaluation of high temperature components to determine their suitability for use in high temperature geothermal tools. Development of high temperature components has been increasing rapidly due to demand from the high temperature oil and gas exploration and aerospace industries. Many of these new components are at the late prototype or first production stage of development and could benefit from third party evaluation of functionality and lifetime at elevated temperatures. In addition to independent testing of new components, this project recognizes that there is a paucity of commercial-off-the-shelf COTS components rated for geothermal temperatures. As such, high-temperature circuit designers often must dedicate considerable time and resources to determine if a component exists that they may be able to knead performance out of to meet their requirements. This project aids tool developers by characterization of select COTS component performances beyond published temperature specifications. The process for selecting components includes public announcements of project intent (e.g., FedBizOps), direct discussions with candidate manufacturers,and coordination with other DOE funded programs.

  16. Highly Active New a-Diimine Nickel Catalyst for Polymerization of Ethylene

    Institute of Scientific and Technical Information of China (English)

    YUAN Jian-chao; LIU Yu-feng; MEI Tong-jian; WANG Xue-hu

    2011-01-01

    A new a-diimine ligand 1a,bis[N,N'-(4-tert-butyl-2,6-dimethylphenyl)imino]-2,3-butanediylidene and its corresponding Ni(II)complex 2a,{bis[N,N'-(4-tert-butyi-2,6-dimethylphenyi)imino]-2,3-butanediylidene}dibromonickel were successfully synthesized,and characterized by 1H NMR,13C NMR,Fourier transform infrared spectroscope(FTIR),elemental analysis and X-ray photoelectron spectroscopy(XPS).a-Diimine ligand 1b,bis[N,N'-(2,6-dimethylphenyl)imino]-2,3-butanediylidene and its corresponding Ni(Ⅱ)complex 2b,{bis[N,N'-(2,6-dimethylphenyl)imino]-2,3-butanediylidene}dibromonickel were also synthesized and characterized for comparison.The pre-catalyst 2a with sterically bulky,electron-donating group tert-butyl,activated by diethylaluminum chloride (DEAC)and tested in the polymerization of ethylene,was very highly active[2.01 × 107g PE/(mol Ni.h·0.1 MPa)]and led to a very highly branched polyethylene(ca.35-103 branches/1000 C).The state of the polyethylene obtained varied from plastic,elastomer polymers to the oil-like hyperbranched polymers.

  17. Knitted Strain Sensor Textiles of Highly Conductive All-Polymeric Fibers.

    Science.gov (United States)

    Seyedin, Shayan; Razal, Joselito M; Innis, Peter C; Jeiranikhameneh, Ali; Beirne, Stephen; Wallace, Gordon G

    2015-09-30

    A scaled-up fiber wet-spinning production of electrically conductive and highly stretchable PU/PEDOT:PSS fibers is demonstrated for the first time. The PU/PEDOT:PSS fibers possess the mechanical properties appropriate for knitting various textile structures. The knitted textiles exhibit strain sensing properties that were dependent upon the number of PU/PEDOT:PSS fibers used in knitting. The knitted textiles show sensitivity (as measured by the gauge factor) that increases with the number of PU/PEDOT:PSS fibers deployed. A highly stable sensor response was observed when four PU/PEDOT:PSS fibers were co-knitted with a commercial Spandex yarn. The knitted textile sensor can distinguish different magnitudes of applied strain with cyclically repeatable sensor responses at applied strains of up to 160%. When used in conjunction with a commercial wireless transmitter, the knitted textile responded well to the magnitude of bending deformations, demonstrating potential for remote strain sensing applications. The feasibility of an all-polymeric knitted textile wearable strain sensor was demonstrated in a knee sleeve prototype with application in personal training and rehabilitation following injury.

  18. High performance nature of biodegradable polymeric nanocomposites for oil-well drilling fluids

    Directory of Open Access Journals (Sweden)

    Tarek M. Madkour

    2016-06-01

    Full Text Available Multi-walled carbon nanotube (MWCNT and graphene nanoplatelet reinforced thermoplastic poly(lactic acid (PLA biodegradable nanocomposites were designed and prepared using solution casting techniques. The prepared biodegradable polymers are expected to provide an environmentally friendly alternative to petroleum-based polymers. Both nanocomposite systems exhibited better thermal stability and improved mechanical performance over the unreinforced polymer exhibiting excellent strength and degradability. The addition of graphene nanofiller in varied amounts was aimed to enhance the thermal and mechanical properties of the nanocomposites even further and incorporate the outstanding characteristics of graphene nanoplatelets into the nanocomposites. The polymeric nanocomposites showed also superior advantages for oil drilling relevances, automotive lubricating purposes, membrane technology and food packaging. Scanning electron microscopy images indicated a homogeneous dispersion of the nanofiller within the polymeric matrix at low filler loadings and a cluster formation at higher loadings that could be responsible for the polymeric matrix movement restrictions. The enthalpy of mixing (the polymer and the nanofiller measured could explain the cause of the repulsive interactions between the nanoparticles and the polymeric chains, which created an additional excluded volume that the polymeric segments were restricted to occupy, thus forcing the conformational characteristics of the polymeric chains to deviate away from those of the bulk chains. The prepared polymeric nano composites (poly lactic acid carbon nano tube and poly lactic acid graphene nanoplatelets were utilized in the formulation of oil-base mud as a viscosifier. The rheological, filtration properties and electrical stability of the oil based mud formulation with the new polymeric nanocomposite were studied and the result compared to the oil-based mud formulation with commercial viscosifier.

  19. Dimensionality of high temperature superconductivity in oxides

    Science.gov (United States)

    Chu, C. W.

    1989-01-01

    Many models have been proposed to account for the high temperature superconductivity observed in oxide systems. Almost all of these models proposed are based on the uncoupled low dimensional carrier Cu-O layers of the oxides. Results of several experiments are presented and discussed. They suggest that the high temperature superconductivity observed cannot be strictly two- or one-dimensional, and that the environment between the Cu-O layers and the interlayer coupling play an important role in the occurrence of such high temperature superconductivity. A comment on the very short coherence length reported is also made.

  20. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 k) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  1. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 K) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  2. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    the operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen overpotentials. Current...

  3. Symposium on high temperature and materials chemistry

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    This volume contains the written proceedings of the Symposium on High Temperature and Materials Chemistry held in Berkeley, California on October 24--25, 1989. The Symposium was sponsored by the Materials and Chemical Sciences Division of Lawrence Berkeley Laboratory and by the College of Chemistry of the University of California at Berkeley to discuss directions, trends, and accomplishments in the field of high temperature and materials chemistry. Its purpose was to provide a snapshot of high temperature and materials chemistry and, in so doing, to define status and directions.

  4. Silicon Carbide Nanotube Oxidation at High Temperatures

    Science.gov (United States)

    Ahlborg, Nadia; Zhu, Dongming

    2012-01-01

    Silicon Carbide Nanotubes (SiCNTs) have high mechanical strength and also have many potential functional applications. In this study, SiCNTs were investigated for use in strengthening high temperature silicate and oxide materials for high performance ceramic nanocomposites and environmental barrier coating bond coats. The high · temperature oxidation behavior of the nanotubes was of particular interest. The SiCNTs were synthesized by a direct reactive conversion process of multiwall carbon nanotubes and silicon at high temperature. Thermogravimetric analysis (TGA) was used to study the oxidation kinetics of SiCNTs at temperatures ranging from 800degC to1300degC. The specific oxidation mechanisms were also investigated.

  5. Development of high temperature capable piezoelectric sensors

    Science.gov (United States)

    Suprock, Andrew D.; Tittmann, Bernhard R.

    2017-02-01

    The objective of the project was to investigate the influence of the temperature effect on ultrasonic transducers based on a comparison of the effects of high temperature conditions versus those of high temperature and irradiation on the transducer system. There was also a preliminary move towards the establishment of the means for optimizing the bulk single crystal transducer fabrication process in order to achieve peak efficiency and maximum effectiveness in both irradiated and non-irradiated high temperature applications. Optimization of the material components within the transducer will greatly increase non-destructive testing abilities for industry, structural health monitoring. Here is presented a progress report on the testing of several different piezoelectric materials under high temperature conditions. The viability of aluminum nitride (AlN) as a transducer material in high temperature conditions has been previously explored [1] and has been further tested to ensure reliability. Bistmuth Titanate (BiT) has also been tested and has displayed excellent effectiveness for high temperature application.

  6. TEPIC -- A new high temperature structural foam

    Energy Technology Data Exchange (ETDEWEB)

    L. L. Whinnery; S. H. Goods; M. L. Tootle; C. L. Neuschwanger

    1998-10-01

    The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 C, are reported. In each of these respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. The authors' approach was to combine chemistries known to form thermally stable products. The principal polymerization products are an oxizolidinone produced by the reaction of the isocyanate with the epoxide and isocyanurate rings formed by the trimerization of the isocyanate. Processing has been examined and large-scale production is discussed in detail. Compared to APO-BMI processing, TEPIC processing is facile and economical. The structure of the foam resembles a traditional rigid polyurethane foam rather than that of the APO-BMI. That is, the foam is comprised of a continuous resin phase rather than weakly bonded glass microballoons. At a density of 0.42 g/cm{sup 3} or greater, maximum pore size in TEPIC was less than 2 mm, as required for the application.

  7. Broadband, High-Temperature Ultrasonic Transducer

    Science.gov (United States)

    Parker, F. Raymond; Winfree, William P.; Barrows, Danny A.

    1995-01-01

    Materials chosen for endurance at high temperatures and acoustic coupling and damping. Acoustic transducer designed to exhibit broad frequency response and to survive temperatures close to melting points of brazing alloys. Attached directly and continuously to hot object monitored ultrasonically: for example, it can be attached to relatively cool spot on workpiece during brazing for taking ultrasonic quality-control measurements.

  8. Magnetic properties of polymerized diphenyloctatetrayne

    Energy Technology Data Exchange (ETDEWEB)

    Beristain, Miriam F.; Jimenez-Solomon, Maria F.; Ortega, Alejandra; Escudero, Roberto [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Ciudad Universitaria, Mexico DF 04510 (Mexico); Munoz, Eduardo [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, Ciudad Universitaria, Mexico DF 01000 (Mexico); Maekawa, Yasunari; Koshikawa, Hiroshi [High Performance Polymer Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Ogawa, Takeshi, E-mail: ogawa@unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, Ciudad Universitaria, Mexico DF 04510 (Mexico)

    2012-10-15

    A new type of metal-free ferromagnetic carbon material was obtained by thermal polymerization and electron beam irradiation of diphenyloctatetrayne (DPOT). The isothermal magnetic measurements showed hysteresis loops indicating weak but intrinsic ferromagnetism with Curie temperatures of around 600 K. Electron spin resonance spectroscopy showed that the material contained stable free radicals in the range of 10{sup 17}-10{sup 20} radicals g{sup -1} depending on the polymerization process. The ferromagnetism should be due to high radical concentration although no correlation was observed between them. It was shown that an amorphous ferromagnetic carbon could be obtained from a simple crystalline solid by heating at moderate temperatures. Highlights: Black-Right-Pointing-Pointer Diphenyloctatetrayne as a precursor for carbon with high radical concentration. Black-Right-Pointing-Pointer The carbon material consists of sp{sup 2} configuration. Black-Right-Pointing-Pointer A weak intrinsic metal-free ferromagnetism was observed for the carbon products.

  9. Surface functionalization of macroporous polymeric materials by treatment with air low temperature plasma.

    Science.gov (United States)

    Molina, R; Sole, I; Vílchez, A; Bertran, E; Solans, C; Esquena, J

    2013-04-01

    Polystyrene/divinylbenzene (PS-DVB) macroporous monoliths obtained using highly concentrated emulsions as templates show a superhydrophobic behaviour, restricting their potential technological applications, especially those related to adhesion and wetting. Air plasma treatments were carried out in order to modulate wetting properties, modifying the surface chemical composition of macroporous polystyrene/divinylbenzene materials. The superhydrophobic behaviour was rapidly suppressed by air plasma treatment, greatly reducing the water contact angle, from approximately 150 degrees to approximately 90 degrees, in only 10 seconds of treatment. The new surface chemical groups, promoted by plasma active species, were characterized by surface analysis techniques with different depth penetration specificity (contact angle, XPS, FTIR and SEM). Results demonstrated that very short treatment times produced different chemical functionalities, mainly C-O, C=O, O-C=O and C-N, which provide the materials with predominantly acidic surface properties. However, plasma active species did not penetrate deeply through the interconnected pores of the material. FTIR analysis evidenced that the new hydrophilic surface groups promoted by plasma active species are in a negligibly concentration compared to bulk chemical groups, and are located in a very thin surface region on the PS-DVB monolith surface (significantly below 2 microm). XPS analysis of treated monoliths revealed a progressive increase of oxygen and nitrogen content as a function of plasma treatment time. However, oxidation of the PS-DVB monoliths surface prevails over the incorporation of nitrogen atoms. Finally, SEM studies indicated that the morphology of the plasma treated PS-DVB does not significantly change even for the longest air plasma treatment time studied (120 s).

  10. Reverse phase high-performance liquid chromatography for quantification of hydroxymethylnitrofurazone in polymeric nanoparticles

    Directory of Open Access Journals (Sweden)

    Lis Marie Monteiro

    2015-09-01

    Full Text Available Hydroxymethylnitrofurazone (NFOH is a new compound with potential leishmanicidal and trypanocidal activity. Despite its effectiveness, the formulators have to overcome its poor aqueous solubility. Recently, polymeric nano-scale drug delivery systems have proposed for the treatment of neglected diseases. As several studies have confirmed the advantages of such formulations, and this approach provides new analytical challenges, including the need to detect trace amounts of the drug. A suitable method was developed and validated for NFOH determination bound to poly (n-butylcyanoacrylate (PBCA nanoparticles. The chromatographic separation was achieved using a C18 column maintained at 25 ºC and an isocratic mobile phase consisting of water and acetonitrile: 80:20 (v/v at a flow rate of 1.2 mL min-1 and UV-detection at 265 nm. Investigated validation parameters included selectivity, linearity, accuracy, precision and robustness (changes in column temperature, mobile phase composition and flow. The method was specific, the peak of NFOH had no interference with any nanoparticle excipients and no co-elution with main degradation product (nitrofurazone. Linearity was over the range of 0.94 13.11 μg mL-1 (r2=0.999. The method was accurate and precise, recovery of 100.7%, RSD of 0.4%; intra-day and inter-day RSD range 9.98-9.99 μg mL-1 and 0.3% to 0.5%, respectively. Robustness confirmed that method could resist the applied changes. Application of the optimized method revealed an encapsulation efficiency of 64.4% (n=3. Therefore, the method was successfully developed and validated for the determination of the encapsulation efficiency of NFOH-PBCA nanoparticles.

  11. High Temperature Fiberoptic Thermal Imaging System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Phase 1 program will fabricate and demonstrate a small diameter single fiber endoscope that can perform high temperature thermal imaging in a jet engine...

  12. High Temperature Self-Healing Metallic Composite

    Science.gov (United States)

    Kutelia, E. R.; Bakhtiyarov, S. I.; Tsurtsumia, O. O.; Bakhtiyarov, A. S.; Eristavi, B.

    2012-01-01

    This work presents the possibility to realize the self healing mechanisms for heterogeneous architectural metal/ceramic high temperature sandwich thermal barrier coating systems on the surfaces refractory metals by analogy of wound healing in the skin.

  13. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High temperature power electronics have become a vital aspect of future designs for power converters in spacecraft, battle zone electric power, satellite power...

  14. Panel report on high temperature ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Nolet, T C [ed.

    1979-01-01

    Fundamental research is reported concerning high temperature ceramics for application in turbines, engines, batteries, gasifiers, MHD, fuel cells, heat exchangers, and hot wall combustors. Ceramics microstructure and behavior are included. (FS)

  15. Application Fields of High-Temperature Superconductors

    OpenAIRE

    Hott, Roland

    2003-01-01

    Potential application fields for cuprate high-temperature superconductors (HTS) and the status of respective projects are reviewed. The availability of a reliable and inexpensive cooling technique will be essential for a future broad acceptance of HTS applications.

  16. Measuring Moduli Of Elasticity At High Temperatures

    Science.gov (United States)

    Wolfenden, Alan

    1993-01-01

    Shorter, squatter specimens and higher frequencies used in ultrasonic measurement technique. Improved version of piezo-electric ultrasonic composite oscillator technique used to measure moduli of elasticity of solid materials at high temperatures.

  17. Silicon carbide, an emerging high temperature semiconductor

    Science.gov (United States)

    Matus, Lawrence G.; Powell, J. Anthony

    1991-01-01

    In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

  18. Novel High Temperature Strain Gauge Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced high-temperature sensor technology and bonding methods are of great interests in designing and developing advanced future aircraft. Current state-of-the-art...

  19. Polymeric microspheres

    Science.gov (United States)

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  20. Lanthanide-containing polymer microspheres by multiple-stage dispersion polymerization for highly multiplexed bioassays.

    Science.gov (United States)

    Abdelrahman, Ahmed I; Dai, Sheng; Thickett, Stuart C; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A

    2009-10-28

    We describe the synthesis and characterization of metal-encoded polystyrene microspheres by multiple-stage dispersion polymerization with diameters on the order of 2 mum and a very narrow size distribution. Different lanthanides were loaded into these microspheres through the addition of a mixture of lanthanide salts (LnCl(3)) and excess acrylic acid (AA) or acetoacetylethyl methacrylate (AAEM) dissolved in ethanol to the reaction after about 10% conversion of styrene, that is, well after the particle nucleation stage was complete. Individual microspheres contain ca. 10(6)-10(8) chelated lanthanide ions, of either a single element or a mixture of elements. These microspheres were characterized one-by-one utilizing a novel mass cytometer with an inductively coupled plasma (ICP) ionization source and time-of-flight (TOF) mass spectrometry detection. Microspheres containing a range of different metals at different levels of concentration were synthesized to meet the requirements of binary encoding and enumeration encoding protocols. With four different metals at five levels of concentration, we could achieve a variability of 624, and the strategy we report should allow one to obtain much larger variability. To demonstrate the usefulness of element-encoded beads for highly multiplexed immunoassays, we carried out a proof-of-principle model bioassay involving conjugation of mouse IgG to the surface of La and Tm containing particles and its detection by an antimouse IgG bearing a metal-chelating polymer with Pr.

  1. A Green Platform for Preparation of the Well-Defined Polyacrylonitrile: 60Co γ-ray Irradiation-Initiated RAFT Polymerization at Room Temperature

    Directory of Open Access Journals (Sweden)

    Shuangshuang Zhang

    2017-01-01

    Full Text Available 60Co γ-ray irradiation-initiated reversible addition–fragmentation chain transfer (RAFT polymerization at room temperature with 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN as the chain transfer agent was first applied to acrylonitrile (AN polymerization, providing a “green” platform for preparing polyacrylonitrile (PAN-based carbon fibers using an environment-friendly energy source. Various effects of dose rate, molar ratio of the monomer to the chain transfer agent, monomer concentration and reaction time on the AN polymerization behaviors were performed to improve the controllability of molecular the weight and molecular weight distribution of the obtained PAN. The feature of the controlled polymerization was proven by the first-order kinetics, linear increase of the molecular weight with the monomer conversion and a successful chain-extension experiment. The molecular weight and molecular weight distribution of PAN were characterized by size exclusion chromatography (SEC. 1H NMR and Matrix assisted laser desorption ionization/time of flight mass spectra (MALDI-TOF-MS confirmed the chain-end functionality of PAN, which also was supported by the successful chain-extension experiments of original PANs with acrylonitrile and styrene as the second monomers respectively.

  2. High temperature superconductors and other superfluids

    CERN Document Server

    Alexandrov, A S

    2017-01-01

    Written by eminent researchers in the field, this text describes the theory of superconductivity and superfluidity starting from liquid helium and a charged Bose-gas. It also discusses the modern bipolaron theory of strongly coupled superconductors, which explains the basic physical properties of high-temperature superconductors. This book will be of interest to fourth year graduate and postgraduate students, specialist libraries, information centres and chemists working in high-temperature superconductivity.

  3. PLA recycling by hydrolysis at high temperature

    Science.gov (United States)

    Cristina, Annesini Maria; Rosaria, Augelletti; Sara, Frattari; Fausto, Gironi

    2016-05-01

    In this work the process of PLA hydrolysis at high temperature was studied, in order to evaluate the possibility of chemical recycling of this polymer bio-based. In particular, the possibility to obtain the monomer of lactic acid from PLA degradation was investigated. The results of some preliminary tests, performed in a laboratory batch reactor at high temperature, are presented: the experimental results show that the complete degradation of PLA can be obtained in relatively low reaction times.

  4. Recent developments in high temperature organic polymers

    Science.gov (United States)

    Hergenrother, P. M.

    1991-01-01

    Developments in high temperature organic polymers during the last 5 years with major emphasis on polyimides and poly(arylene ether)s are discussed. Specific polymers or series of polymers have been selected to demonstrate unique properties or the effect chemical structure has upon certain properties. This article is not intended to be a comprehensive review of high temperature polymer advancements during the last 5 years.

  5. Polymerization Using Phosphazene Bases

    KAUST Repository

    Zhao, Junpeng

    2015-09-01

    In the recent rise of metal-free polymerization techniques, organic phosphazene superbases have shown their remarkable strength as promoter/catalyst for the anionic polymerization of various types of monomers. Generally, the complexation of phosphazene base with the counterion (proton or lithium cation) significantly improves the nucleophilicity of the initiator/chain end resulting in highly enhanced polymerization rates, as compared with conventional metalbased initiating systems. In this chapter, the general features of phosphazenepromoted/catalyzed polymerizations and the applications in macromolecular engineering (synthesis of functionalized polymers, block copolymers, and macromolecular architectures) are discussed with challenges and perspectives being pointed out.

  6. High-temperature discontinuously reinforced aluminum

    Science.gov (United States)

    Zedalis, M. S.; Bryant, J. D.; Gilman, P. S.; Das, S. K.

    1991-08-01

    High-temperature discontinuously reinforced aluminum (HTDRA) composites have been developed for elevated-temperature applications by incorporating SiC particulate reinforcement into a rapidly solidified, high-temperature Al-Fe-V-Si (alloy 8009) matrix. HTDRA combines the superior elevated-temperature strength, stability and corrosion resistance of the 8009 matrix with the excellent specific stiffness and abrasion resistance of the discontinuous SiC particulate reinforcement. On a specific stiffness basis, HTDRA is competitive with Ti-6-Al-4V and 17-4 PH stainless steel to temperatures approaching 480°C. Potential aerospace applications being considered for HTDRA include aircraft wing skins, missile bodies, and miscellaneous engine, spacecraft and hypersonic vehicle components.

  7. Polymerization shrinkage and depth of cure of bulk-fill resin composites and highly filled flowable resin.

    Science.gov (United States)

    Jang, J-H; Park, S-H; Hwang, I-N

    2015-01-01

    The aim of this study was to evaluate the polymerization behavior and depth of cure (DOC) of recently introduced resin composites for posterior use: highly filled flowable composite and composites for bulk fill. A highly filled flowable (G-aenial Universal Flo [GUF]), two bulk-fill flowables (Surefil SDR Flow [SDR] and Venus Bulk fill [VBF]), and a bulk-fill nonflowable composite (Tetric N-Ceram Bulk fill [TBF]) were compared with two conventional composites (Tetric Flow [TF], Filtek Supreme Ultra [FS]). Linear polymerization shrinkage and polymerization shrinkage stress were each measured with custom-made devices. To evaluate DOC, the composite specimen was prepared using a mold with a hole of 4 mm depth and 4 mm internal diameter. The hole was bulk filled with each of the six composites and light cured for 20 seconds, followed by 24 hours of water storage. The surface hardness was measured on the top and the bottom using a Vickers microhardness (HV) indenter. The linear polymerization shrinkage of the composite specimens after photo-initiation decreased in the following order: TF and GUF > VBF > SDR > FS and TBF (pcomposite groups decreased in the following order: GUF > TF and VBF > SDR > FS and TBF (pflowable (GUF) revealed limitations in polymerization shrinkage and DOC. Bulk-fill flowables (SDR and VBF) were properly cured in 4-mm bulk, but they shrank more than the conventional nonflowable composite. A bulk-fill nonflowable (TBF) showed comparable shrinkage to the conventional nonflowable composite, but it was not sufficiently cured in the 4-mm bulk.

  8. Laser Plasma Coupling for High Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W.

    1999-11-04

    Simple scaling models indicate that quite high radiation temperatures can be achieved in hohlraums driven with the National Ignition Facility. A scaling estimate for the radiation temperature versus pulse duration for different size NIF hohlraums is shown in Figure 1. Note that a radiation temperature of about 650 ev is projected for a so-called scale 1 hohlraum (length 2.6mm, diameter 1.6mm). With such high temperature hohlraums, for example, opacity experiments could be carried out using more relevant high Z materials rather than low Z surrogates. These projections of high temperature hohlraums are uncertain, since the scaling model does not allow for the very strongly-driven laser plasma coupling physics. Lasnex calculations have been carried out to estimate the plasma and irradiation conditions in a scale 1 hohlraum driven by NIF. Linear instability gains as high as exp(100) have been found for stimulated Brillouin scattering, and other laser-driven instabilities are also far above their thresholds. More understanding of the very strongly-driven coupling physics is clearly needed in order to more realistically assess and improve the prospects for high temperature hohlraums. Not surprisingly, this regime has been avoided for inertial fusion applications and so is relatively unexplored.

  9. Relativistic QED Plasma at Extremely High Temperature

    CERN Document Server

    Masood, Samina S

    2016-01-01

    Renormalization scheme of QED (Quantum Electrodynamics) at high temperatures is used to calculate the effective parameters of relativistic plasma in the early universe. Renormalization constants of QED play role of effective parameters of the theory and can be used to determine the collective behavior of the medium. We explicitly show that the dielectric constant, magnetic reluctivity, Debye length and the plasma frequency depend on temperature in the early universe. Propagation speed, refractive index, plasma frequency and Debye shielding length of a QED plasma are computed at extremely high temperatures in the early universe. We also found the favorable conditions for the relativistic plasma from this calculations.

  10. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  11. High Temperature, Wireless Seismometer Sensor for Venus

    Science.gov (United States)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

    2012-01-01

    Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

  12. High-temperature granulites and supercontinents

    Institute of Scientific and Technical Information of China (English)

    J.L.R. Touret; M. Santosh; J.M. Huizenga

    2016-01-01

    The formation of continents involves a combination of magmatic and metamorphic processes. These processes become indistinguishable at the crust-mantle interface, where the pressure-temperature (P-T) conditions of (ultra) high-temperature granulites and magmatic rocks are similar. Continents grow laterally, by magmatic activity above oceanic subduction zones (high-pressure metamorphic setting), and vertically by accumulation of mantle-derived magmas at the base of the crust (high-temperature metamorphic setting). Both events are separated from each other in time; the vertical accretion post-dating lateral growth by several tens of millions of years. Fluid inclusion data indicate that during the high-temperature metamorphic episode the granulite lower crust is invaded by large amounts of low H2O-activity fluids including high-density CO2 and concentrated saline solutions (brines). These fluids are expelled from the lower crust to higher crustal levels at the end of the high-grade metamorphic event. The final amalgamation of supercontinents corresponds to episodes of ultra-high temperature metamorphism involving large-scale accumulation of these low-water activity fluids in the lower crust. This accumulation causes tectonic instability, which together with the heat input from the sub-continental lithospheric mantle, leads to the disruption of supercontinents. Thus, the fragmentation of a supercontinent is already programmed at the time of its amalgamation.

  13. High-temperature granulites and supercontinents

    Directory of Open Access Journals (Sweden)

    J.L.R. Touret

    2016-01-01

    Full Text Available The formation of continents involves a combination of magmatic and metamorphic processes. These processes become indistinguishable at the crust-mantle interface, where the pressure-temperature (P-T conditions of (ultra high-temperature granulites and magmatic rocks are similar. Continents grow laterally, by magmatic activity above oceanic subduction zones (high-pressure metamorphic setting, and vertically by accumulation of mantle-derived magmas at the base of the crust (high-temperature metamorphic setting. Both events are separated from each other in time; the vertical accretion postdating lateral growth by several tens of millions of years. Fluid inclusion data indicate that during the high-temperature metamorphic episode the granulite lower crust is invaded by large amounts of low H2O-activity fluids including high-density CO2 and concentrated saline solutions (brines. These fluids are expelled from the lower crust to higher crustal levels at the end of the high-grade metamorphic event. The final amalgamation of supercontinents corresponds to episodes of ultra-high temperature metamorphism involving large-scale accumulation of these low-water activity fluids in the lower crust. This accumulation causes tectonic instability, which together with the heat input from the sub-continental lithospheric mantle, leads to the disruption of supercontinents. Thus, the fragmentation of a supercontinent is already programmed at the time of its amalgamation.

  14. High-entropy alloys as high-temperature thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Shafeie, Samrand [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Guo, Sheng, E-mail: sheng.guo@chalmers.se [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Hu, Qiang [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China); Fahlquist, Henrik [Bruker AXS Nordic AB, 17067 Solna (Sweden); Erhart, Paul [Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Palmqvist, Anders, E-mail: anders.palmqvist@chalmers.se [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2015-11-14

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  15. High-entropy alloys as high-temperature thermoelectric materials

    Science.gov (United States)

    Shafeie, Samrand; Guo, Sheng; Hu, Qiang; Fahlquist, Henrik; Erhart, Paul; Palmqvist, Anders

    2015-11-01

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  16. The tempered polymerization of human neuroserpin.

    Directory of Open Access Journals (Sweden)

    Rosina Noto

    Full Text Available Neuroserpin, a member of the serpin protein superfamily, is an inhibitor of proteolytic activity that is involved in pathologies such as ischemia, Alzheimer's disease, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB. The latter belongs to a class of conformational diseases, known as serpinopathies, which are related to the aberrant polymerization of serpin mutants. Neuroserpin is known to polymerize, even in its wild type form, under thermal stress. Here, we study the mechanism of neuroserpin polymerization over a wide range of temperatures by different techniques. Our experiments show how the onset of polymerization is dependent on the formation of an intermediate monomeric conformer, which then associates with a native monomer to yield a dimeric species. After the formation of small polymers, the aggregation proceeds via monomer addition as well as polymer-polymer association. No further secondary mechanism takes place up to very high temperatures, thus resulting in the formation of neuroserpin linear polymeric chains. Most interesting, the overall aggregation is tuned by the co-occurrence of monomer inactivation (i.e. the formation of latent neuroserpin and by a mechanism of fragmentation. The polymerization kinetics exhibit a unique modulation of the average mass and size of polymers, which might suggest synchronization among the different processes involved. Thus, fragmentation would control and temper the aggregation process, instead of enhancing it, as typically observed (e.g. for amyloid fibrillation.

  17. High-temperature superconducting conductors and cables

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-09-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J{sub c} in high magnetic fields at temperatures near liq. N2`s bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J{sub c} at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices.

  18. High Temperature VARTM of Phenylethynyl Terminated Imides

    Science.gov (United States)

    Ghose, Sayata; Watson, Kent A.; Cano, Roberto J.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.

    2009-01-01

    LaRC phenylethynyl terminated imide (PETI) resins were processed into composites using high temperature vacuum assisted resin transfer molding (VARTM). Although initial runs yielded composites with high void content, process modifications reduced voids to <3%. Photomicrographs were taken and void contents and T(sub g)s of the panels were determined.

  19. Reactive Plasticizers for High Temperature Quinoxaline Thermoplastics

    Science.gov (United States)

    1976-06-01

    involves essentially two steps, consolidation of boardy prepreg into sheet stock and thermoforming the sheet stock into structural components. A...problem associated with the fabrication process is the high temperatures required in both the consolidation and thermoforming operations. High processing

  20. Fluctuations and correlations in high temperature QCD

    CERN Document Server

    Bellwied, R; Fodor, Z; Katz, S D; Pasztor, A; Ratti, C; Szabo, K K

    2015-01-01

    We calculate second- and fourth-order cumulants of conserved charges in a temperature range stretching from the QCD transition region towards the realm of (resummed) perturbation theory. We perform lattice simulations with staggered quarks; the continuum extrapolation is based on $N_t=10\\dots24$ in the crossover-region and $N_t=8\\dots16$ at higher temperatures. We find that the Hadron Resonance Gas model predictions describe the lattice data rather well in the confined phase. At high temperatures (above $\\sim$250 MeV) we find agreement with the three-loop Hard Thermal Loop results.

  1. Ultra High Temperature Ceramics for aerospace applications

    OpenAIRE

    Jankowiak, A.; Justin, J.F.

    2014-01-01

    Après relecture une erreur est apparue dans le document et doit être retiré; International audience; The Ultra High Temperature Ceramics (UHTCs) are of great interest for different engineering sectors and notably the aerospace industry. Indeed, hypersonic flights, re-entry vehicles, propulsion applications and so on, require new materials that can perform in oxidizing or corrosive atmospheres at temperatures higher than 2000°C and sometimes, for long life-time. To fulfil these requirements, U...

  2. Effects of High Temperature on Collector Coatings

    Science.gov (United States)

    Lowery, J. R.

    1982-01-01

    Report reveals electroplated black chrome is good coating for concentrating collectors in which temperatures are in the 650 degrees-800 degrees F (340 degrees - 430 degrees C) range. Black chrome thermal emittance is low and solar-absorption properties are not seriously degraded at high temperatures. Black coatings are used to increase absorption of solar energy by base metal while decreasing emission of infrared energy. Coatings are intended to improve efficiency of solar collectors.

  3. Polybenzimidazoles based on high temperature polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Linares Leon, Jose Joaquin; Camargo, Ana Paula M.; Ashino, Natalia M.; Morgado, Daniella L.; Frollini, Elisabeth; Paganin, Valdecir A.; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil); Bajo, Justo Lobato [University of Castilla-La Mancha, Ciudad Real (Spain). Dept. of Chemical Engineering

    2010-07-01

    This work presents an interesting approach in order to enhance the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFC) by means of an increase in the operational temperature. For this, two polymeric materials, Poly(2,5-bibenzimidazole) (ABPBI) and Poly[2,2'-(m-phenyl en)-5,5' bib enzimidazol] (PBI), impregnated with phosphoric acid have been utilized. These have shown excellent properties, such as thermal stability above 500 deg C, reasonably high conductivity when impregnated with H{sub 3}PO{sub 4} and a low permeability to alcohols compared to Nafion. Preliminary fuel cells measurements on hydrogen based Polymer Electrolyte Membrane Fuel Cell (PEMFC) displayed an interestingly reasonable good fuel cell performance, a quite reduced loss when the hydrogen stream was polluted with carbon monoxide, and finally, when the system was tested with an ethanol/water (E/W) fuel, it displayed quite promising results that allows placing this system as an attractive option in order to increase the cell performance and deal with the typical limitations of low temperature Nafion-based PEMFC. (author)

  4. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    , a single-family house designed for plus-energy targets and equipped with a radiant water-based floor heating and cooling system was studied by means of full-scale measurements, dynamic building simulations and thermodynamic evaluation tools. Thermal indoor environment and energy performance of the house...... performance of heating and cooling systems for achieving the same thermal indoor environment. The results show that it is crucial to minimize the heating and cooling demands in the design phase since these demands determine the terminal units and heat sources and sinks that could be used. Low temperature...... heating and high temperature cooling systems (a radiant water-based floor heating and cooling system in this study) proved to be superior to compared systems, evaluated with different system analysis tools; energy, exergy, and entransy. Radiant systems should be coupled to appropriate heating and cooling...

  5. Synthesis, characterization and dye removal ability of high capacity polymeric adsorbent: Polyaminoimide homopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodi, Niyaz Mohammad, E-mail: nm_mahmoodi@aut.ac.ir [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Najafi, Farhood [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Khorramfar, Shooka [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Amini, Farrokhlegha [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Arami, Mokhtar [Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer Polyaminoimide homopolymer (PAIHP) was synthesized and characterized. Black-Right-Pointing-Pointer Kinetics data followed pseudo-second order kinetic model. Black-Right-Pointing-Pointer Isotherm data followed Langmuir isotherm. Black-Right-Pointing-Pointer Q{sub 0} for DR31, DR23, DB22 and AB25 was 6667, 5555, 9090 and 5882 mg/g, respectively. Black-Right-Pointing-Pointer PAIHP was regenerated at pH 12. - Abstract: In this paper, polyaminoimide homopolymer (PAIHP) was synthesized and its dye removal ability was investigated. Physical characteristics of PAIHP were studied using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Direct Red 31 (DR31), Direct Red 23 (DR23), Direct Black 22 (DB22) and Acid Blue 25 (AB25) were used as model compounds. The kinetic and isotherm of dye adsorption were studied. The effect of operational parameter such as adsorbent dosage, pH and salt on dye removal was evaluated. Adsorption kinetic of dyes followed pseudo-second order kinetics. The maximum dye adsorption capacity (Q{sub 0}) of PAIHP was 6667 mg/g, 5555 mg/g, 9090 mg/g and 5882 mg/g for DR31, DR23, DB22 and AB25, respectively. It was found that adsorption of DR31, DR23, DB22 and AB25 onto PAIHP followed with Langmuir isotherm. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% for DR31, 86% for DR23, 87% for DB22 and 90% for AB25 were achieved in aqueous solution at pH 12. The results showed that the PAIHP as a polymeric adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored wastewater.

  6. Evolutive characteristics of aromatics under high pressure and temperature of deep lithosphere

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Pyrolysis of lignite in closed systems was conducted at temperatures from 400 to 700℃ and pressure from 1 to 3 GPa in order to investigate the evolutive characteristics of aromatics and the effects of pressure and temperature on the maturation of organic matter under the extreme conditions. The total yield of liquid hydrocarbons decreased with increasing pressure and the aromatics shows more mature with increasing temperature at a given pressure. The data indicate that high pressure significantly suppresses the thermal evolution of geological organic matter especially at lower temperature, but favors the cyclization, polymerization and aromatization of pyrolysate. The pressure effect on maturation of organic matter is nonlinear. Therefore, it can be inferred that sediment organic-matters in the subducted slab could be retained in the deep lithosphere, and the results are also significant for understanding the accumulation and preservation of petroleum in deep reservoirs.key wordshigh pressure and high temperature, lignite, aromatic hydrocarbon, maturation, isomerzation, petroleum in deep reservoirs

  7. Joining of ultra-high temperature ceramics

    OpenAIRE

    Silvestroni, Laura; Sciti, Diletta; Esposito, Laura; Glaeser, Andreas

    2012-01-01

    In the last decade, ultra-high temperature ceramics raised renewed interest after the first studies in the 60's. Thanks to their high melting point, superior to any group of materials, and to their set of interesting physical and engineering properties, they find application in aerospace industry, propulsion field, as cladding materials in generation IV nuclear reactors and solar absorbers in novel HT CSP systems. Recent efforts were devoted to the achievement of high strength and toughness m...

  8. High systemic availability of core-crosslinked polymeric micelles after subcutaneous administration

    NARCIS (Netherlands)

    Hu, Q.; Prakash, Jai; Rijcken, C.J.F.; Hennink, W.E.; Storm, Gerrit

    2016-01-01

    Covalent entrapment of drug molecules within core-crosslinked polymeric micelles (CCPM) represents an attractive approach to improve their therapeutic index. As an alternative to the most commonly employed intravenous (i.v.) route, subcutaneous (s.c.) administration offers the possibility of

  9. High systemic availability of core-crosslinked polymeric micelles after subcutaneous administration

    NARCIS (Netherlands)

    Hu, Q.; Prakash, Jai; Rijcken, C.J.F.; Hennink, W.E.; Storm, Gerrit

    2016-01-01

    Covalent entrapment of drug molecules within core-crosslinked polymeric micelles (CCPM) represents an attractive approach to improve their therapeutic index. As an alternative to the most commonly employed intravenous (i.v.) route, subcutaneous (s.c.) administration offers the possibility of self-ad

  10. High temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of the book describe rationalization and illustration of approaches to high temperature PEM systems. Chapters 6 - 13 are devoted to fabrication, optimization and characterization of phosphoric acid-doped polybenzimidazole membranes, the very first electrolyte system that has demonstrated the concept...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  11. Abiotic formation of valine peptides under conditions of high temperature and high pressure.

    Science.gov (United States)

    Furukawa, Yoshihiro; Otake, Tsubasa; Ishiguro, Takato; Nakazawa, Hiromoto; Kakegawa, Takeshi

    2012-12-01

    We investigated the oligomerization of solid valine and the stabilities of valine and valine peptides under conditions of high temperature (150-200 °C) and high pressure (50-150 MPa). Experiments were performed under non-aqueous condition in order to promote dehydration reaction. After prolonged exposure of monomeric valine to elevated temperatures and pressures, the products were analyzed by liquid chromatography mass spectrometry comparing their retention times and masses. We identified linear peptides that ranged in size from dimer to hexamer, as well as a cyclic dimer. Previous studies that attempted abiotic oligomerization of valine in the absence of a catalyst have never reported valine peptides larger than a dimer. Increased reaction temperature increased the dissociative decomposition of valine and valine peptides to products such as glycine, β-alanine, ammonia, and amines by processes such as deamination, decarboxylation, and cracking. The amount of residual valine and peptide yields was greater at higher pressures at a given temperature, pressure, and reaction time. This suggests that dissociative decomposition of valine and valine peptides is reduced by pressure. Our findings are relevant to the investigation of diagenetic processes in prebiotic marine sediments where similar pressures occur under water-poor conditions. These findings also suggest that amino acids, such as valine, could have been polymerized to peptides in deep prebiotic marine sediments within a few hundred million years.

  12. Abiotic Formation of Valine Peptides Under Conditions of High Temperature and High Pressure

    Science.gov (United States)

    Furukawa, Yoshihiro; Otake, Tsubasa; Ishiguro, Takato; Nakazawa, Hiromoto; Kakegawa, Takeshi

    2012-12-01

    We investigated the oligomerization of solid valine and the stabilities of valine and valine peptides under conditions of high temperature (150-200 °C) and high pressure (50-150 MPa). Experiments were performed under non-aqueous condition in order to promote dehydration reaction. After prolonged exposure of monomeric valine to elevated temperatures and pressures, the products were analyzed by liquid chromatography mass spectrometry comparing their retention times and masses. We identified linear peptides that ranged in size from dimer to hexamer, as well as a cyclic dimer. Previous studies that attempted abiotic oligomerization of valine in the absence of a catalyst have never reported valine peptides larger than a dimer. Increased reaction temperature increased the dissociative decomposition of valine and valine peptides to products such as glycine, β-alanine, ammonia, and amines by processes such as deamination, decarboxylation, and cracking. The amount of residual valine and peptide yields was greater at higher pressures at a given temperature, pressure, and reaction time. This suggests that dissociative decomposition of valine and valine peptides is reduced by pressure. Our findings are relevant to the investigation of diagenetic processes in prebiotic marine sediments where similar pressures occur under water-poor conditions. These findings also suggest that amino acids, such as valine, could have been polymerized to peptides in deep prebiotic marine sediments within a few hundred million years.

  13. High temperature superconductivity the road to higher critical temperature

    CERN Document Server

    Uchida, Shin-ichi

    2015-01-01

    This book presents an overview of material-specific factors that influence Tc and give rise to diverse Tc values for copper oxides and iron-based high- Tc superconductors on the basis of more than 25 years of experimental data, to most of which the author has made important contributions. The book then explains why both compounds are distinct from others with similar crystal structure and whether or not one can enhance Tc, which in turn gives a hint on the unresolved pairing mechanism. This is an unprecedented new approach to the problem of high-temperature superconductivity and thus will be inspiring to both specialists and non-specialists interested in this field.   Readers will receive in-depth information on the past, present, and future of high-temperature superconductors, along with special, updated information on what the real highest Tc values are and particularly on the possibility of enhancing Tc for each member material, which is important for application. At this time, the highest Tc has not been...

  14. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    and pressures. Two measurement systems were built to perform measurements under high pressures and at elevated temperatures of up to 95 bar and 250 °C, respectively. The conductivity of aqueous KOH and aqueous KOH immobilized in a porous SrTiO3 structure were investigated at elevated temperatures and high...... the operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... concentrations of the electrolyte using the van der Pauw method in combination with electrochemical impedance spectroscopy (EIS). Conductivity values as high as 2.9 S cm-1 for 45 wt% KOH aqueous KOH and 0.84 S cm-1 for the immobilized KOH of the same concentration were measured at 200 °C. Porous SrTiO3 was used...

  15. Materials for high-temperature fuel cells

    CERN Document Server

    Jiang, San Ping; Lu, Max

    2013-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in High-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in high-temperature fuel cells with emphasis on the most important solid oxide fuel cells. A related book will cover key mater

  16. High Temperature Protonic Conductors by Melt Growth

    Science.gov (United States)

    2007-11-02

    ceramic materials of BaCe1 -xNdxO3-a and Ba3(CaNb2)O9 that exhibit high temperature protonic conductance and superior mechanical properties at elevated...TEM). The mechanical behavior BaCe1 -xNdxO3-a (x=0 to 0.2) and Ba3(CaNb2)O9 ceramics in the elastic, brittle and plastic regime will be studied...spatial variations of compositions in BaCe1 -xNdxO3-a and Ba3(CaNb2)O9 following high temperature wet atmosphere treatment will be measured using a

  17. High-temperature MAS-NMR at high spinning speeds.

    Science.gov (United States)

    Kirchhain, Holger; Holzinger, Julian; Mainka, Adrian; Spörhase, Andreas; Venkatachalam, Sabarinathan; Wixforth, Achim; van Wüllen, Leo

    2016-09-01

    A low cost version to enable high temperature MAS NMR experiments at temperatures of up to 700°C and spinning speeds of up to 10kHz is presented. The method relies on inductive heating using a metal coated rotor insert. The metal coating is accomplished via a two step process involving physical vapor deposition and galvanization.

  18. High Temperature Mechanisms for Venus Exploration

    Science.gov (United States)

    Ji, Jerri; Narine, Roop; Kumar, Nishant; Singh, Sase; Gorevan, Steven

    Future Venus missions, including New Frontiers Venus In-Situ Explorer and three Flagship Missions - Venus Geophysical Network, Venus Mobile Explorer and Venus Surface Sample Return all focus on searching for evidence of past climate change both on the surface and in the atmospheric composition as well as in the interior dynamics of the planet. In order to achieve these goals and objectives, many key technologies need to be developed for the Venus extreme environment. These key technologies include sample acquisition systems and other high-temperature mechanisms and mobility systems capable of extended operation when directly exposed to the Venus surface or lower atmosphere environment. Honeybee Robotics has developed two types of high temperature motors, the materials and components in both motors were selected based on the requirement to survive temperatures above a minimum of 460° C, at earth atmosphere. The prototype Switched Reluctance Motor (SRM) has been operated non-continuously for over 20 hours at Venus-like conditions (460° C temperature, mostly CO2 gas environment) and it remains functional. A drilling system, actuated by two SRMs was tested in Venus-like conditions, 460° C temperature and mostly CO2 gas environment, for more than 15 hours. The drill successfully completed three tests by drilling into chalk up to 6 inches deep in each test. A first generation Brushless DC (BLDC) Motor and high temperature resolver were also tested and the feasibility of the designs was demonstrated by the extended operation of both devices under Venus-like condition. Further development of the BLDC motor and resolver continues and these devices will, ultimately, be integrated into the development of a high temperature sample acquisition scoop and high temperature joint (awarded SBIR Phase II in October, 2007). Both the SR and BLDC motors will undergo extensive testing at Venus temperature and pressure (TRL6) and are expected to be mission ready before the next New

  19. High temperature reactors for cogeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl [Forschungszentrum Juelich (Germany). IEK-6; Allelein, Hans-Josef [Forschungszentrum Juelich (Germany). IEK-6; RWTH Aachen (Germany). Lehrstuhl fuer Reaktorsicherheit und -technik (LRST)

    2016-05-15

    There is a large potential for nuclear energy also in the non-electric heat market. Many industrial sectors have a high demand for process heat and steam at various levels of temperature and pressure to be provided for desalination of seawater, district heating, or chemical processes. The future generation of nuclear plants will be capable to enter the wide field of cogeneration of heat and power (CHP), to reduce waste heat and to increase efficiency. This requires an adjustment to multiple needs of the customers in terms of size and application. All Generation-IV concepts proposed are designed for coolant outlet temperatures above 500 C, which allow applications in the low and medium temperature range. A VHTR would even be able to cover the whole temperature range up to approx. 1 000 C.

  20. On-wafer high temperature characterization system

    Science.gov (United States)

    Teodorescu, L.; ǎghici, F., Dr; Rusu, I.; Brezeanu, G.

    2016-12-01

    In this work a on-wafer high temperature characterization system for wide bandgap semiconductor devices and circuits has been designed, implemented and tested. The proposed system can perform the wafer temperature adjustment in a large domain, from the room temperature up to 3000C with a resolution better than +/-0.50C. In order to obtain both low-noise measurements and low EMI, the heating element of the wafer chuck is supplied in two ways: one is from a DC linear power supply connected to the mains electricity, another one is from a second DC unit powered by batteries. An original temperature control algorithm, different from classical PID, is used to modify the power applied to the chuck.

  1. High-Temperature Shape Memory Polymers

    Science.gov (United States)

    Yoonessi, Mitra; Weiss, Robert A.

    2012-01-01

    physical conformation changes when exposed to an external stimulus, such as a change in temperature. Such materials have a permanent shape, but can be reshaped above a critical temperature and fixed into a temporary shape when cooled under stress to below the critical temperature. When reheated above the critical temperature (Tc, also sometimes called the triggering or switching temperature), the materials revert to the permanent shape. The current innovation involves a chemically treated (sulfonated, carboxylated, phosphonated, or other polar function group), high-temperature, semicrystalline thermoplastic poly(ether ether ketone) (Tg .140 C, Tm = 340 C) mix containing organometallic complexes (Zn++, Li+, or other metal, ammonium, or phosphonium salts), or high-temperature ionic liquids (e.g. hexafluorosilicate salt with 1-propyl-3- methyl imidazolium, Tm = 210 C) to form a network where dipolar or ionic interactions between the polymer and the low-molecular-weight or inorganic compound forms a complex that provides a physical crosslink. Hereafter, these compounds will be referred to as "additives". The polymer is semicrystalline, and the high-melt-point crystals provide a temporary crosslink that acts as a permanent crosslink just so long as the melting temperature is not exceeded. In this example case, the melting point is .340 C, and the shape memory critical temperature is between 150 and 250 C. PEEK is an engineering thermoplastic with a high Young fs modulus, nominally 3.6 GPa. An important aspect of the invention is the control of the PEEK functionalization (in this example, the sulfonation degree), and the thermal properties (i.e. melting point) of the additive, which determines the switching temperature. Because the compound is thermoplastic, it can be formed into the "permanent" shape by conventional plastics processing operations. In addition, the compound may be covalently cross - linked after forming the permanent shape by S-PEEK by applying ionizing

  2. High-Temperature Capacitor Polymer Films

    Science.gov (United States)

    Tan, Daniel; Zhang, Lili; Chen, Qin; Irwin, Patricia

    2014-12-01

    Film capacitor technology has been under development for over half a century to meet various applications such as direct-current link capacitors for transportation, converters/inverters for power electronics, controls for deep well drilling of oil and gas, direct energy weapons for military use, and high-frequency coupling circuitry. The biaxially oriented polypropylene film capacitor remains the state-of-the-art technology; however, it is not able to meet increasing demand for high-temperature (>125°C) applications. A number of dielectric materials capable of operating at high temperatures (>140°C) have attracted investigation, and their modifications are being pursued to achieve higher volumetric efficiency as well. This paper highlights the status of polymer dielectric film development and its feasibility for capacitor applications. High-temperature polymers such as polyetherimide (PEI), polyimide, and polyetheretherketone were the focus of our studies. PEI film was found to be the preferred choice for high-temperature film capacitor development due to its thermal stability, dielectric properties, and scalability.

  3. High temperature fatigue behaviour of intermetallics

    Indian Academy of Sciences (India)

    K Bhanu Sankara Rao

    2003-06-01

    There would be considerable benefits in developing new structural materials where high use temperatures and strength coupled with low density are minimum capabilities. Nickel and titanium aluminides exhibit considerable potential for near-term application in various branches of modern industry due to the number of property advantages they possess including low density, high melting temperature, high thermal conductivity, and excellent environmental resistance, and their amenability for significant improvment in creep and fatigue resistance through alloying. Reliability of intermetallics when used as engineering materials has not yet been fully established. Ductility and fracture toughness at room and intermediate temperatures continue to be lower than the desired values for production implementation. In this paper, progress made towards improving strain-controlled fatigue resistance of nickel and titanium aluminides is outlined. The effects of manufacturing processes and micro alloying on low cycle fatigue behaviour of NiAl are addressed. The effects of microstructure, temperature of testing, section thickness, brittle to ductile transition temperature, mean stress and environment on fatigue behaviour of same -TiAl alloys are discussed.

  4. High Accuracy, Miniature Pressure Sensor for Very High Temperatures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SiWave proposes to develop a compact, low-cost MEMS-based pressure sensor for very high temperatures and low pressures in hypersonic wind tunnels. Most currently...

  5. Parametric investigation of substrate temperatures on the properties of Zinc oxide deposited over a flexible polymeric substrate via spray technique

    Science.gov (United States)

    Rajagopalan, P.; Gagrani, Rohit; Nakamura, Daisuke; Okada, Tatsuo; Singh, Vipul; Palani, I. A.

    2016-09-01

    Here we report the influence of substrate temperature (300-500 °C) on the deposition and growth of ZnO over a Flexible polyimide film. Owing to its simplicity, large area deposition capability and Cost effectivity Spray Pyrolysis technique was used. We have modified the conventional process of Spray pyrolysis by spraying for shorter durations and repeating the process which in turn reduced the Island formation of ZnO. Moreover, this technique helped in maintaining the constant temperature and uniformity during the deposition as prolonged spraying reduces the temperature of the heating plate drastically. Photoluminescence (PL) reveals that at 350 and 400° C the defect have reduced. XRD reveals the crystallinity and Impurities present. FE-SEM reveals the structure morphology changes with the change in the substrate temperature. TGA was done to ensure that substrate does not undergoes dissociation at high temperature. It was observed at the film deposited at 400 °C was found to be more uniform, defect free and crystalline. Hence, IV characterization of the film deposited at 400 °C was done which showed good rectification behaviour of the Schottky diodes.

  6. High Temperature Polymer Electrolyte Fuel Cells

    DEFF Research Database (Denmark)

    Fleige, Michael

    This thesis presents the development and application of electrochemical half-cell setups to study the catalytic reactions taking place in High Temperature Polymer Electrolyte Fuel Cells (HTPEM-FCs): (i) a pressurized electrochemical cell with integrated magnetically coupled rotating disk electrode...... of dissolved oxygen. A potential step method (hydrodynamic chronocoulometry) is evaluated for simultaneous measurement of diffusivity and solubility of oxygen by means of RDE. Finally, the ORR tests are extended to conc. H3PO4 at more relevant working temperatures and under increased oxygen pressure. Direct...... of platinumphosphoric acid. At room temperature, a relative slow ORR hindering process is active, which requires using a fast method (cyclic voltammetry with high scan rate / hydrodynamic chronocoulometry) to accurately measure the diffusion limited currents, and thus, oxygen diffusivity and solubility. In conc. H3PO4...

  7. Gravimeter using high-temperature superconductor bearing.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.

    1998-09-11

    We have developed a sensitive gravimeter concept that uses an extremely low-friction bearing based on a permanent magnet (PM) levitated over a high-temperature superconductor (HTS). A mass is attached to the PM by means of a cantilevered beam, and the combination of PM and HTS forms a bearing platform that has low resistance to rotational motion but high resistance to horizontal, vertical, or tilting motion. The combination acts as a low-loss torsional pendulum that can be operated in any orientation. Gravity acts on the cantilevered beam and attached mass, accelerating them. Variations in gravity can be detected by time-of-flight acceleration, or by a control coil or electrode that would keep the mass stationary. Calculations suggest that the HTS gravimeter would be as sensitive as present-day superconducting gravimeters that need cooling to liquid helium temperatures, but the HTS gravimeter needs cooling only to liquid nitrogen temperatures.

  8. Nuclear and Quark Matter at High Temperature

    CERN Document Server

    Biro, T S; Schram, Z

    2016-01-01

    We review important ideas on nuclear and quark matter description on the basis of high- temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the - partially still open - problems of the hadronization process.

  9. Technology of high temperature organic coolant

    Energy Technology Data Exchange (ETDEWEB)

    Makin, R.S.; Vorobei, M.P.; Kuprienko, V.A.; Starkov, V.A.; Tsykanov, V.A.; Checketkin, Y.V. [Research Institute of Atomic Reactors, Ulyanovsk (Russian Federation)

    1993-12-31

    Research has been performed on the problems related to the use of high temperature organic coolants in small and medium nuclear power plants. The work performed and also the experience of operating the ARBUS reactor confirmed the inherent safety features, reliability, and enhanced safety margins of the plants with this type of coolants. The advantages of this system and research highlights are presented.

  10. Enamel for high-temperature superalloys

    Science.gov (United States)

    Levin, H.; Lent, W. E.

    1977-01-01

    Desired optical and high temperature enamel properties are obtained with glasses prepared from the system Li2O-ZrO2-nSiO2. Molar compositions range from n=4 to n=1.3, to which are added minor amounts in varying combinations of alumina, alkali fluorides, boric oxide, alkali oxides, and akaline earth oxides.

  11. Nuclear and quark matter at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Biro, Tamas S. [H.A.S. Wigner Research Centre for Physics, Budapest (Hungary); Jakovac, Antal [Roland Eotvos University, Budapest (Hungary); Schram, Zsolt [University of Debrecen, Institute for Theoretical Physics, Debrecen (Hungary)

    2017-03-15

    We review important ideas on nuclear and quark matter description on the basis of high-temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the -partially still open- problems of the hadronization process. (orig.)

  12. Analysis of iron oxidation at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, J.C.; Peng, K.Y.; Gadalla, A.M.; Gadalla, N. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemical Engineering

    1995-10-01

    A new theory for the high-temperature oxidation of iron is proposed, in which the rate-limiting step is ternary diffusion of ferric, ferrous, and oxygen ions in the iron oxides that are formed. The predictions of this theory are compared with previously published experimental data. The only thermodynamic information required is a phase diagram.

  13. Dynamics of Gauge Fields at High Temperature

    NARCIS (Netherlands)

    Nauta, B.J.

    2000-01-01

    An effective description of dynamical Bose fields is provided by the classical (high-temperature) limit of thermal field theory. The main subject of this thesis is to improve the ensuing classical field theory, that is, to include the dominant quantum corrections and to add counter terms for the Ray

  14. Photoemission studies of high-temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Margaritondo, G. (Inst. de Physique Appliquee, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (CH))

    1990-11-01

    Photoemission spectroscopy has recently emerged as one of the leading techniques in the study of high-temperature superconductors. Relevant successes include the direct detection of the superconductivity gap, tests for departure from Fermi-liquid behavior, and many interface chemical studies with technological interest. The authors present a review of the fundamental and applied aspects of this technique.

  15. High-temperature carbidization of carboniferous rocks

    Science.gov (United States)

    Goldin, B. A.; Grass, V. E.; Nadutkin, A. V.; Nazarova, L. Yu.

    2009-08-01

    Processes of thermal metamorphism of carboniferous rocks have been studied experimentally. The conditions of high-temperature interaction of shungite carbon with components of the contained rocks, leading to formation of carbide compounds, have been determined. The results of this investigation contribute to the works on searching for new raw material for prospective material production.

  16. 10.3 High-temperature Instrumentation

    Science.gov (United States)

    Piazza, Anthony

    2008-01-01

    This viewgraph presentation describes high temperature instrumentation development from 1960-1970, 1980-1990 and 2000-present. The contents include: 1) Background; 2) Objective; 3) Application and Sensor; 4) Attachment Techniques; 5) Evaluation/Characterization Testing; and 6) Future testing.

  17. Anharmonic phonons and high-temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H.; Cohen, M.L. (Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States))

    1993-07-01

    We examine a simple model of anharmonic phonons with application to the superconducting isotope effect. Linear and quadratic electron-phonon coupling are considered for various model potentials. The results of the model calculations are compared with the high-temperature superconductors La[sub 2[minus][ital x

  18. High-temperature langasite SAW oxygen sensor.

    Science.gov (United States)

    Zheng, Peng; Chin, Tao-Lun; Greve, David; Oppenheim, Irving; Malone, Vanessa; Cao, Limin

    2011-08-01

    High-temperature langasite SAW oxygen sensors using sputtered ZnO as a resistive gas-sensing layer were fabricated and tested. Sensitivity to oxygen gas was observed between 500°C to 700°C, with a sensitivity peak at about 625°C, consistent with the theoretical predictions of the acoustoelectric effect.

  19. Dynamics of Gauge Fields at High Temperature

    NARCIS (Netherlands)

    Nauta, B.J.

    2000-01-01

    An effective description of dynamical Bose fields is provided by the classical (high-temperature) limit of thermal field theory. The main subject of this thesis is to improve the ensuing classical field theory, that is, to include the dominant quantum corrections and to add counter terms for the Ray

  20. Solar-driven high temperature radiant cooling

    Institute of Scientific and Technical Information of China (English)

    SONG ZhaoPei; WANG RuZhu; ZHAI XiaoQiang

    2009-01-01

    Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller's COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%.According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion.

  1. High Temperature Corrosion in Biomass Incineration Plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel; Gotthjælp, K.

    1997-01-01

    The aim of the project is to study the role of ash deposits in high temperature corrosion of superheater materials in biomass and refuse fire combined heat and power plants. The project has included the two main activities: a) A chemical characterisation of ash deposits collected from a major...

  2. The Evolution of High Temperature Gas Sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, F. H. (Fernando H.); Brosha, E. L. (Eric L.); Mukundan, R. (Rangachary)

    2001-01-01

    Gas sensor technology based on high temperature solid electrolytes is maturing rapidly. Recent advances in metal oxide catalysis and thin film materials science has enabled the design of new electrochemical sensors. We have demonstrated prototype amperometric oxygen sensors, nernstian potentiometric oxygen sensors that operate in high sulfur environments, and hydrocarbon and carbon monoxide sensing mixed potentials sensors. Many of these devices exhibit part per million sensitivities, response times on the order of seconds and excellent long-term stability.

  3. High temperature internal friction measurements of 3YTZP zirconia polycrystals. High temperature background and creep

    OpenAIRE

    Simas, P.; Castillo-Rodríguez, Miguel; Nó, M. L.; De-Bernardi, S.; Gómez-García, D.; Domínguez-Rodríguez, Alejandro; San Juan, J.

    2014-01-01

    This work focuses on the high-temperature mechanic properties of a 3 mol % yttria zirconia polycrystals (3YTZP), fabricated by hot-pressureless sintering. Systematic measurements of mechanical loss as a function of temperature and frequency were performed. An analytical method, based on the generalised Maxwell rheological model, has been used to analyse the high temperature internal friction background (HTB). This method has been previously applied to intermetallic compounds...

  4. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V

    2002-01-01

    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  5. High temperature furnace modeling and performance verifications

    Science.gov (United States)

    Smith, James E., Jr.

    1992-01-01

    Analytical, numerical, and experimental studies were performed on two classes of high temperature materials processing sources for their potential use as directional solidification furnaces. The research concentrated on a commercially available high temperature furnace using a zirconia ceramic tube as the heating element and an Arc Furnace based on a tube welder. The first objective was to assemble the zirconia furnace and construct parts needed to successfully perform experiments. The 2nd objective was to evaluate the zirconia furnace performance as a directional solidification furnace element. The 3rd objective was to establish a data base on materials used in the furnace construction, with particular emphasis on emissivities, transmissivities, and absorptivities as functions of wavelength and temperature. A 1-D and 2-D spectral radiation heat transfer model was developed for comparison with standard modeling techniques, and were used to predict wall and crucible temperatures. The 4th objective addressed the development of a SINDA model for the Arc Furnace and was used to design sample holders and to estimate cooling media temperatures for the steady state operation of the furnace. And, the 5th objective addressed the initial performance evaluation of the Arc Furnace and associated equipment for directional solidification. Results of these objectives are presented.

  6. High temperature superconductors applications in telecommunications

    Science.gov (United States)

    Kumar, A. Anil; Li, Jiang; Zhang, Ming Fang

    1995-01-01

    The purpose of this paper is twofold: (1) to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and (2) to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices - obvious advantages versus practical difficulties - needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models - a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B) - shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance - conductivity, surface resistance and attenuation constant - will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T

  7. High temperature superconductors applications in telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.A.; Li, J.; Zhang, M.F. [Prairie View A& M Univ., Texas (United States)

    1994-12-31

    The purpose of this paper is twofold: to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices-obvious advantages versus practical difficulties-needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models-a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B)-shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance-conductivity, surface resistance and attenuation constant-will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T{sub c} superconductors.

  8. X-Aerogels for Structural Components and High Temperature Applications

    Science.gov (United States)

    2005-01-01

    Future NASA missions and space explorations rely on the use of materials that are strong ultra lightweight and able to withstand extreme temperatures. Aerogels are low density (0.01-0.5 g/cu cm) high porosity materials that contain a glass like structure formed through standard sol-gel chemistry. As a result of these structural properties, aerogels are excellent thermal insulators and are able to withstand temperatures in excess of l,000 C. The open structure of aerogels, however, renders these materials extremely fragile (fracturing at stress forces less than 0.5 N/sq cm). The goal of NASA Glenn Research Center is to increase the strength of these materials by templating polymers and metals onto the surface of an aerogel network facilitating the use of this material for practical applications such as structural components of space vehicles used in exploration. The work this past year focused on two areas; (1) the research and development of new templated aerogels materials and (2) process development for future manufacturing of structural components. Research and development occurred on the production and characterization of new templating materials onto the standard silica aerogel. Materials examined included polymers such as polyimides, fluorinated isocyanates and epoxies, and, metals such as silver, gold and platinum. The final properties indicated that the density of the material formed using an isocyanate is around 0.50 g/cc with a strength greater than that of steel and has low thermal conductivity. The process used to construct these materials is extremely time consuming and labor intensive. One aspect of the project involved investigating the feasibility of shortening the process time by preparing the aerogels in the templating solvent. Traditionally the polymerization used THF as the solvent and after several washes to remove any residual monomers and water, the solvent around the aerogels was changed to acetonitrile for the templating step. This process

  9. Reverse phase high-performance liquid chromatography for quantification of hydroxymethylnitrofurazone in polymeric nanoparticles

    OpenAIRE

    Lis Marie Monteiro; Guilherme Diniz Tavares; Elizabeth Igne Ferreira; Vladi Olga Consiglieri; Nadia Araci Bou-Chacra; Raimar Löbenberg

    2015-01-01

    Hydroxymethylnitrofurazone (NFOH) is a new compound with potential leishmanicidal and trypanocidal activity. Despite its effectiveness, the formulators have to overcome its poor aqueous solubility. Recently, polymeric nano-scale drug delivery systems have proposed for the treatment of neglected diseases. As several studies have confirmed the advantages of such formulations, and this approach provides new analytical challenges, including the need to detect trace amounts of the drug. A suitable...

  10. Comments on theories of high temperature superconductivity

    Directory of Open Access Journals (Sweden)

    T. M. Rice

    2006-09-01

    Full Text Available   The recently discovered MgB2 superconductors have a record transition temperature for a BCS superconductor due to the high vibration frequencies associated with its light elements. The transition temperatures in the cuprate family of superconductors are much higher but these do not fit the BCS paradigm. The most promising microscopic origin for their many anomalous properties lies in magnetic pairing described by the RVB (Resonant Valence Bond ansatz. However a comprehensive theoretical description of the key anomalous properties of the cuprates remains to be an open challenge.

  11. The metallurgy of high temperature alloys

    Science.gov (United States)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  12. Optically transparent high temperature shape memory polymers.

    Science.gov (United States)

    Xiao, Xinli; Qiu, Xueying; Kong, Deyan; Zhang, Wenbo; Liu, Yanju; Leng, Jinsong

    2016-03-21

    Optically transparent shape memory polymers (SMPs) have potential in advanced optoelectronic and other common shape memory applications, and here optically transparent shape memory polyimide is reported for the first time. The polyimide possesses a glass transition temperature (Tg) of 171 °C, higher than the Tg of other transparent SMPs reported, and the influence of molecular structure on Tg is discussed. The 120 μm thick polyimide film exhibits transmittance higher than 81% in 450-800 nm, and the possible mechanism of its high transparency is analyzed, which will benefit further research on other transparent high temperature SMPs. The transparent polyimide showed excellent thermomechanical properties and shape memory performances, and retained high optical transparency after many shape memory cycles.

  13. High temperature sensors for exhaust diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Svenningstorp, Henrik

    2000-07-01

    One of the largest problems that we will have to deal with on this planet this millennium is to stop the pollution of our environment. In many of the ongoing works to reduce toxic emissions, gas sensors capable of enduring rough environments and high temperatures, would be a great tool. The different applications where sensors like this would be useful vary between everything from online measurement in the paper industry and food industry to measurement in the exhaust pipe of a car. In my project we have tested Schottky diodes and MlSiCFET sensor as gas sensors operating at high temperatures. The measurement condition in the exhaust pipe of a car is extremely tough, not only is the temperature high and the different gases quite harmful, there are also a lot of particles that can affect the sensors in an undesirable way. In my project we have been testing Schottky diodes and MlSiCFET sensors based on SiC as high temperature sensors, both in the laboratory with simulated exhaust and after a real engine. In this thesis we conclude that these sensors can work in the hostile environment of an engines exhaust. It is shown that when measuring in a gas mixture with a fixed I below one, where the I-value is controlled by the O{sub 2} concentration, a sensor with a catalytic gate metal as sensitive material respond more to the increased O{sub 2} concentration than the increased HC concentration when varying the two correspondingly. A number of different sensors have been tested in simulated exhaust towards NO{sub x}. It was shown that resistivity changes in the thin gate metal influenced the gas response. Tests have been performed where sensors were a part of a SCR system with promising results concerning NH{sub 3} sensitivity. With a working temperature of 300 deg C there is no contamination of the metal surface.

  14. High Temperature Fluoride Salt Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Richard Burns [Univ. of Tennessee, Knoxville, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peretz, Fred J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  15. Thermoelectric properties by high temperature annealing

    Science.gov (United States)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Kumar, Shankar (Inventor); Lee, Hohyun (Inventor)

    2009-01-01

    The present invention generally provides methods of improving thermoelectric properties of alloys by subjecting them to one or more high temperature annealing steps, performed at temperatures at which the alloys exhibit a mixed solid/liquid phase, followed by cooling steps. For example, in one aspect, such a method of the invention can include subjecting an alloy sample to a temperature that is sufficiently elevated to cause partial melting of at least some of the grains. The sample can then be cooled so as to solidify the melted grain portions such that each solidified grain portion exhibits an average chemical composition, characterized by a relative concentration of elements forming the alloy, that is different than that of the remainder of the grain.

  16. High Temperature Polymer Electrolyte Fuel Cells

    DEFF Research Database (Denmark)

    Fleige, Michael

    This thesis presents the development and application of electrochemical half-cell setups to study the catalytic reactions taking place in High Temperature Polymer Electrolyte Fuel Cells (HTPEM-FCs): (i) a pressurized electrochemical cell with integrated magnetically coupled rotating disk electrode...... (RDE) and (ii) a gas diffusion electrode (GDE) setup designed for experiments in conc. H3PO4. The pressurized cell is demonstrated by tests on polycrystalline platinum electrodes up to 150 ºC. Functionality of the RDE system is proved studying the oxygen reduction reaction (ORR) at temperatures up...... to 140 ºC and oxygen pressures up to ~100 bar at room temperature. The GDE cell is successfully tested at 130 ºC by means of direct oxidation of methanol and ethanol, respectively. In the second part of the thesis, the emphasis is put on the ORR in H3PO4 with particular focus on the mass transport...

  17. Quench in high temperature superconductor magnets

    CERN Document Server

    Schwartz, J

    2013-01-01

    High field superconducting magnets using high temperature superconductors are being developed for high energy physics, nuclear magnetic resonance and energy storage applications. Although the conductor technology has progressed to the point where such large magnets can be readily envisioned, quench protection remains a key challenge. It is well-established that quench propagation in HTS magnets is very slow and this brings new challenges that must be addressed. In this paper, these challenges are discussed and potential solutions, driven by new technologies such as optical fiber based sensors and thermally conducting electrical insulators, are reviewed.

  18. Influence of bacterial exopolymers on cell adhesion of Desulfovibrio vulgaris on high alloyed steel: Corrosion inhibition by extracellular polymeric substances (EPS)

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, R.; Wei, L.; Fuerbeth, W. [Karl-Winnacker-Institut, DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main (Germany); Grooters, M.; Kuklinski, A. [University of Duisburg-Essen, Biofilm Centre, Geibelstrasse 41, 47057 Duisburg (Germany)

    2010-12-15

    Extracellular polymeric substances (EPS) were studied with regard to their potential application as inhibitors of biocorrosion. EPS that have been isolated from biofilms of sulphate-reducing bacteria (SRB) were adsorbed on samples of high alloyed steel (type 1.4301) at different temperatures. The samples were exposed to SRB containing solution and afterwards analysed by fluorescence microscopy (FM). The results show that the EPS form an incomplete layer and lead to a smaller amount of cell adhesion when compared to pure surfaces. The results are discussed with regard to the application of EPS for the prevention of biofilm formation. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Gasification of high ash, high ash fusion temperature bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  20. Gasification of high ash, high ash fusion temperature bituminous coals

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  1. Polymeric bicontinuous microemulsions

    DEFF Research Database (Denmark)

    Bates, F.S.; Maurer, W.W.; Lipic, P.M.

    1997-01-01

    High molecular weight block copolymers can be viewed as macromolecular surfactants when blended with thermodynamically incompatible homopolymers. This Letter describes the formation of polymeric bicontinuous microemulsions in nurtures containing a model diblock copolymer and two homopolymers...

  2. Dominant role of wormlike micelles in temperature-responsive viscoelastic properties of their mixtures with polymeric chains

    KAUST Repository

    Molchanov, Vyacheslav S.

    2013-03-01

    Temperature effects on the rheological properties of viscoelastic solutions containing entangled wormlike micelles of potassium oleate and hydrophobically modified polyacrylamide were studied in a wide range of polymer concentrations. A very pronounced drop of viscosity by four orders of magnitude was observed at heating from 20 to 78 °C both in the presence and in the absence of polymer indicating that the wormlike micelles are mainly responsible for this effect. The highly thermosensitive behavior was attributed to the shortening of micellar chains induced by heating. Although the decrease in viscosity is almost the same for both surfactant and surfactant/polymer systems, the absolute values of the viscosity in the presence of polymer are by few orders of magnitude higher, which is due to the formation of a common network of entangled polymer and micellar chains. As a result, the added polymer allows one to get highly temperature responsive system that keeps viscoelastic properties in a much wider range of temperatures, which makes it very promising for various practical applications. © 2012 Elsevier Inc.

  3. Energy storage via high temperature superconductivity (SMES)

    Energy Technology Data Exchange (ETDEWEB)

    Mikkonen, R. [Tampere Univ. of Technology (Finland)

    1998-10-01

    The technology concerning high temperature superconductors (HTS) is matured to enabling different kind of prototype applications including SMES. Nowadays when speaking about HTS systems, attention is focused on the operating temperature of 20-30 K, where the critical current and flux density are fairly close to 4.2 K values. In addition by defining the ratio of the energy content of a novel HTS magnetic system and the required power to keep the system at the desired temperature, the optimum settles to the above mentioned temperature range. In the frame of these viewpoints a 5 kJ HTS SMES system has been designed and tested at Tampere University of Technology with a coil manufactured by American Superconductor (AMSC). The HTS magnet has inside and outside diameters of 252 mm and 317 mm, respectively and axial length of 66 mm. It operates at 160 A and carries a total of 160 kA-turns to store the required amount of energy. The effective magnetic inductance is 0.4 H and the peak axial field is 1.7 T. The magnet is cooled to the operating temperature of 20 K with a two stage Gifford-McMahon type cryocooler with a cooling power of 60 W at 77 K and 8 W at 20 K. The magnetic system has been demonstrated to compensate a short term loss of power of a sensitive consumer

  4. High temperature deformation of silicon steel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Calvillo, Pablo, E-mail: pablo.rodriguez@ctm.com.es [CTM - Technologic Centre, Materials Technology Area, Manresa, Cataluna (Spain); Department of Materials Science and Metallurgical Engineering, Universidad Politecnica de Cataluna, Barcelona (Spain); Houbaert, Yvan, E-mail: Yvan.Houbaert@UGent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Petrov, Roumen, E-mail: Roumen.Petrov@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Kestens, Leo, E-mail: Leo.kestens@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Colas, Rafael, E-mail: rafael.colas@uanl.edu.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon (Mexico)

    2012-10-15

    The microstructure and texture development during high temperature plane strain compression of 2% in weight silicon steel was studied. The tests were carried out at a constant strain rate of 5 s{sup -1} with reductions of 25, 35 and 75% at temperatures varying from 800 to 1100 Degree-Sign C. The changes in microstructure and texture were studied by means of scanning electron microscopy and electron backscattered diffraction. The microstructure close to the surface of the samples was equiaxed, which is attributed to the shear caused by friction, whereas that at the centre of the specimens was made of a mixture of elongated and fine equiaxed grains, the last ones attributed to the action of dynamic recovery followed by recrystallization. It was found that the volume fraction of these equiaxed grains augmented as reduction and temperature increased; a 0.7 volume fraction was accomplished with a 75% reduction at 1100 Degree-Sign C. The texture of the equiaxed and elongated grains was found to vary with the increase of deformation and temperature, as the {gamma}-fibre tends to disappear and the {alpha}-fibre to increase towards the higher temperature range. -- Highlights: Black-Right-Pointing-Pointer The plastic deformation of a silicon containing steel is studied by plane strain compression. Black-Right-Pointing-Pointer Equiaxed and elongated grains develop in different regions of the sample due to recrystallization. Black-Right-Pointing-Pointer Texture, by EBSD, is revealed to be similar in either type of grains.

  5. Electrochemical high-temperature gas sensors

    Science.gov (United States)

    Saruhan, B.; Stranzenbach, M.; Yüce, A.; Gönüllü, Y.

    2012-06-01

    Combustion produced common air pollutant, NOx associates with greenhouse effects. Its high temperature detection is essential for protection of nature. Component-integration capable high-temperature sensors enable the control of combustion products. The requirements are quantitative detection of total NOx and high selectivity at temperatures above 500°C. This study reports various approaches to detect NO and NO2 selectively under lean and humid conditions at temperatures from 300°C to 800°C. All tested electrochemical sensors were fabricated in planar design to enable componentintegration. We suggest first an impedance-metric gas sensor for total NOx-detection consisting of NiO- or NiCr2O4-SE and PYSZ-electrolyte. The electrolyte-layer is about 200μm thickness and constructed of quasi-single crystalline columns. The sensing-electrode (SE) is magnetron sputtered thin-layers of NiO or NiCr2O4. Sensor sensitivity for detection of total NOx has been measured by applying impedance analysis. The cross-sensitivity to other emission gases such as CO, CO2, CH4 and oxygen (5 vol.%) has been determined under 0-1000ppm NO. Sensor maintains its high sensitivity at temperatures up to 550°C and 600°C, depending on the sensing-electrode. NiO-SE yields better selectivity to NO in the presence of oxygen and have shorter response times comparing to NiCr2O4-SE. For higher temperature NO2-sensing capability, a resistive DC-sensor having Al-doped TiO2-sensing layers has been employed. Sensor-sensitivity towards NO2 and cross-sensitivity to CO has been determined in the presence of H2O at temperatures 600°C and 800°C. NO2 concentrations varying from 25 to 100ppm and CO concentrations from 25 to 75ppm can be detected. By nano-tubular structuring of TiO2, NO2 sensitivity of the sensor was increased.

  6. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    to 250 °C and 2400 bar, in the deep petroleum reservoirs. Furthermore, many of these deep reservoirs are found offshore, including the North Sea and the Gulf of Mexico, making the development even more risky. On the other hand, development of these high pressure high temperature (HPHT) fields can...

  7. Pulse Radiolysis at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Christensen, H.; Sehested, Knud

    1981-01-01

    A set-up enabling pulse radiolysis measurements at high temperatures (up to 320°C) and high pressures (up to 140 bar) has been constructed in collaboration between Risö National Laboratory and Studsvik Energiteknik. The cell has been used for experiments with aqueous solutions with the purpose...

  8. Rapidly-deposited polydopamine coating via high temperature and vigorous stirring: formation, characterization and biofunctional evaluation.

    Directory of Open Access Journals (Sweden)

    Ping Zhou

    Full Text Available Polydopamine (PDA coating provides a promising approach for immobilization of biomolecules onto almost all kinds of solid substrates. However, the deposition kinetics of PDA coating as a function of temperature and reaction method is not well elucidated. Since dopamine self-polymerization usually takes a long time, therefore, rapid-formation of PDA film becomes imperative for surface modification of biomaterials and medical devices. In the present study, a practical method for preparation of rapidly-deposited PDA coating was developed using a uniquely designed device, and the kinetics of dopamine self-polymerization was investigated by QCM sensor system. It was found that high temperature and vigorous stirring could dramatically speed up the formation of PDA film on QCM chip surface. Surface characterization, BSA binding study, cell viability assay and antibacterial test demonstrates that the polydopamine coating after polymerization for 30 min by our approach exhibits similar properties to those of 24 h counterpart. The method has a great potential for rapid-deposition of polydopamine films to modify biomaterial surfaces.

  9. Rapidly-deposited polydopamine coating via high temperature and vigorous stirring: formation, characterization and biofunctional evaluation.

    Science.gov (United States)

    Zhou, Ping; Deng, Yi; Lyu, Beier; Zhang, Ranran; Zhang, Hai; Ma, Hongwei; Lyu, Yalin; Wei, Shicheng

    2014-01-01

    Polydopamine (PDA) coating provides a promising approach for immobilization of biomolecules onto almost all kinds of solid substrates. However, the deposition kinetics of PDA coating as a function of temperature and reaction method is not well elucidated. Since dopamine self-polymerization usually takes a long time, therefore, rapid-formation of PDA film becomes imperative for surface modification of biomaterials and medical devices. In the present study, a practical method for preparation of rapidly-deposited PDA coating was developed using a uniquely designed device, and the kinetics of dopamine self-polymerization was investigated by QCM sensor system. It was found that high temperature and vigorous stirring could dramatically speed up the formation of PDA film on QCM chip surface. Surface characterization, BSA binding study, cell viability assay and antibacterial test demonstrates that the polydopamine coating after polymerization for 30 min by our approach exhibits similar properties to those of 24 h counterpart. The method has a great potential for rapid-deposition of polydopamine films to modify biomaterial surfaces.

  10. Rapidly-Deposited Polydopamine Coating via High Temperature and Vigorous Stirring: Formation, Characterization and Biofunctional Evaluation

    Science.gov (United States)

    Zhou, Ping; Deng, Yi; Lyu, Beier; Zhang, Ranran; Zhang, Hai; Ma, Hongwei; Lyu, Yalin; Wei, Shicheng

    2014-01-01

    Polydopamine (PDA) coating provides a promising approach for immobilization of biomolecules onto almost all kinds of solid substrates. However, the deposition kinetics of PDA coating as a function of temperature and reaction method is not well elucidated. Since dopamine self-polymerization usually takes a long time, therefore, rapid-formation of PDA film becomes imperative for surface modification of biomaterials and medical devices. In the present study, a practical method for preparation of rapidly-deposited PDA coating was developed using a uniquely designed device, and the kinetics of dopamine self-polymerization was investigated by QCM sensor system. It was found that high temperature and vigorous stirring could dramatically speed up the formation of PDA film on QCM chip surface. Surface characterization, BSA binding study, cell viability assay and antibacterial test demonstrates that the polydopamine coating after polymerization for 30 min by our approach exhibits similar properties to those of 24 h counterpart. The method has a great potential for rapid-deposition of polydopamine films to modify biomaterial surfaces. PMID:25415328

  11. High temperature alloys: their exploitable potential

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.B.; Merz, M.; Nihoul, J.; Ward, J. (eds.) (Commission of the European Communities, Petten (Netherlands). Joint Nuclear Research Center; NET-TEAM, Garching (DE))

    1987-01-01

    This book is the proceedings of a conference dealing with fundamental and technical aspects of the applications of high temperature alloys. It is split into five sections which cover the opening session of the conference and four further sessions covering: the theoretical and practical limits for HT alloys; the potential for development in alloys and processing; engineering considerations; the future outlook. The different sessions each included a number of invited papers followed by a series of posters and were concluded by a presentation of a 'synthesis' by a session rapporteur and general discussion. This structure is retained in the proceedings, including the discussion points in those cases where the authors have provided written answers to the questions raised. This book will be of interest to metallurgists, materials scientists, physicists and research workers in high temperature materials.

  12. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg

    2013-01-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 ◦C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive...... media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells......, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established...

  13. High temperature superconductors for magnetic suspension applications

    Science.gov (United States)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  14. High temperature superconductor materials and applications

    Science.gov (United States)

    Doane, George B., III. (Editor); Banks, Curtis; Golben, John

    1991-01-01

    One of the areas concerned itself with the investigation of the phenomena involved in formulating and making in the laboratory new and better superconductor material with enhanced values of critical current and temperature. Of special interest were the chemistry, physical processes, and environment required to attain these enhanced desirable characteristics. The other area concerned itself with producing high temperature superconducting thin films by pulsed laser deposition techniques. Such films are potentially very useful in the detection of very low power signals. To perform this research high vacuum is required. In the course of this effort, older vacuum chambers were maintained and used. In addition, a new facility is being brought on line. This latter activity has been replete with the usual problems of bringing a new facility into service. Some of the problems are covered in the main body of this report.

  15. Fast pyrolysis of biomass at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna

    This Ph.D. thesis describes experimental and modeling investigations of fast high temperature pyrolysis of biomass. Suspension firing of biomass is widely used for power generation and has been considered as an important step in reduction of greenhouse gas emissions by using less fossil fuels. Fast...... pyrolysis at high temperatures plays a significant role in the overall combustion process since the biomass type, the reaction kinetics and heat transfer rates during pyrolysis influence the volatile gas release. The solid residue yield and its properties in suspension firing, including particle size...... and shape, composition, reactivity and burnout depend significantly on the operating conditions of the fast pyrolysis. Biomass fast pyrolysis experiments were performed in a laboratory-scale wire mesh reactor and bench scale atmospheric pressure drop tube / entrained flow reactors with the aim...

  16. High Temperature Phenomena in Shock Waves

    CERN Document Server

    2012-01-01

    The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

  17. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  18. High temperature mechanical properties of iron aluminides

    Directory of Open Access Journals (Sweden)

    Morris, D. G.

    2001-04-01

    Full Text Available Considerable attention has been given to the iron aluminide family of intermetallics over the past years since they offer considerable potential as engineering materials for intermediate to high temperature applications, particularly in cases where extreme oxidation or corrosion resistance is required. Despite efforts at alloy development, however, high temperature strength remains low and creep resistance poor. Reasons for the poor high-temperature strength of iron aluminides will be discussed, based on the ordered crystal structure, the dislocation structure found in the material, and the mechanisms of dislocation pinning operating. Alternative ways of improving high temperature strength by microstructural modification and the inclusion of second phase particles will also be considered.

    Durante los últimos años se ha prestado mucha atención a la familia de intermetálicos Fe-Al, puesto que estos constituyen un considerable potencial como materiales de ingeniería en aplicaciones a temperaturas intermedias o altas, sobre todo en casos donde se necesita alta resistencia a la oxidación o corrosión. A pesar del considerable esfuerzo desarrollado para obtener aleaciones con mejores propiedades, su resistencia mecánica a alta temperatura no es muy elevada. Se discutirán los aspectos que contribuyen a la baja resistencia mecánica a temperatura elevada en función de la estructura de dislocaciones y los mecanismos de anclaje que operan en este intermetálico. Se considerarán, también, maneras alternativas para mejorar la resistencia a temperatura elevada mediante la modificación de la microestructura y la incorporación de partículas de segunda fase.

  19. High Temperature Perforating System for Geothermal Applications

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Moises E. [Schlumberger Technology Corporation, Sugar Land, TX (United States)

    2017-02-28

    The objective of this project is to develop a perforating system consisting of all the explosive components and hardware, capable of reliable performance in high temperatures geothermal wells (>200 ºC). In this light we will focused on engineering development of these components, characterization of the explosive raw powder and developing the internal infrastructure to increase the production of the explosive from laboratory scale to industrial scale.

  20. On quark number susceptibilities at high temperatures

    CERN Document Server

    Bazavov, A; Hegde, P; Karsch, F; Miao, C; Mukherjee, Swagato; Petreczky, P; Schmidt, C; Velytsky, A

    2013-01-01

    We calculated second and fourth order quark number susceptibilities for 2+1 flavor QCD in the high temperature region using two improved staggered fermion formulations. The calculations are performed at several lattice spacing and we show that in the continuum limit the two formulations give consistent results. We compare our continuum extrapolated results on quark number susceptibilities with recent weak coupling calculations, and find that these cannot simultaneously explain the lattice results for second and fourth order quark number susceptibilities.

  1. Intermetallic-based high-temperature materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-07-01

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminides are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  2. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  3. Hydrogen dominant metallic alloys: high temperature superconductors?

    Science.gov (United States)

    Ashcroft, N W

    2004-05-07

    The arguments suggesting that metallic hydrogen, either as a monatomic or paired metal, should be a candidate for high temperature superconductivity are shown to apply with comparable weight to alloys of metallic hydrogen where hydrogen is a dominant constituent, for example, in the dense group IVa hydrides. The attainment of metallic states should be well within current capabilities of diamond anvil cells, but at pressures considerably lower than may be necessary for hydrogen.

  4. High Temperature Superconducting Maglev Measurement System

    OpenAIRE

    Wang, Jia-Su; Wang, Su-Yu

    2010-01-01

    Three high temperature superconducting (HTS) Maglev measurement systems were successfully developed in the Applied Superconductivity Laboratory (ASCLab) of Southwest Jiaotong University, P. R. China. These systems include liquid nitrogen vessel, Permanent Magnet Guideway (PMG), data collection and processing, mechanical drive and Autocontrol features. This chapter described the three different measuring systems along with their theory of operations and workflow. The SCML-01 HTS Maglev measure...

  5. GRAPHENE PEEK COMPOSITES AS HIGH TEMPERATURE ADHESIVES

    Science.gov (United States)

    2017-09-05

    Price DW, Roberts JA, Scott JB, Wadhawan A, Ye Z, Tour JM. Nanotubes in microwave fields : light emission , intense heat, outgassing, and reconstruction...Arepalli S, Yowell LL, Tour JM. Carbon nanotube composite curing through absorption of microwave radiation. Composites Science and Technology. 2008 Dec...polymer that is suitable for high-temperature applications. Graphene is a two-dimensional form of carbon nanomaterial that has been studied

  6. Technological evolution of high temperature superconductors

    OpenAIRE

    White, Jordan R.

    2015-01-01

    Approved for public release; distribution is unlimited High temperature superconducting (HTS) cables are currently being used in the commercial energy industry primarily for demonstration purposes and to evaluate the feasibility of large-scale implementation into the electric grid. While still in the evaluation stage, the U.S. Navy is finding the test results promising and is investigating its potential use for future electric ships to supply power to electric propulsion motors and possibl...

  7. Development of High-Temperature Strain Gages.

    Science.gov (United States)

    1961-03-17

    lengths the article is either dipped in a slip (finely divided tend to require a support for the grid, while shorter coating material suspended in a...liquid) or the lengths require too many loops to achieve the slip is sprayed onto the article , followed in both cases by high-temperature fusion. An...Electrochemistry. Electrical Instruments. Magnetic Measurements. Dielectrics. Metrology. Photometry and Colorimetry. Refractometry . Photographic Research

  8. Current trends in high temperature design

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, D.L. (Illinois Univ., Urbana, IL (United States). Dept. of Mechanical Engineering)

    1992-01-01

    A review of high temperature design guidelines has been carried out in preparation for designing a solar storage module for the Freedom Spacelab. Three major guidelines, N47, R5 and RCC-MR form the basis of the survey. The main issues with current, mature design in the power industry appear to be adequately covered by these guidelines. A significant finding is that long established models of material damage have survived the test of time very well. A new design regime referred to as Very High Temperature Design (VHTD) is identified. The characteristics of this regime are changing material properties which require some changes in philosophy in drafting of future codes, particularly in regard to definitions of yield strengths and other design allowables. Finally, there is some discussion of the more general use of the stress/strain plane, e.g. isochronous curves, for representation of very complex material constitutive behaviour. A concept called the 'Relaxation Locus', which summarizes essential local constrained component behavior, is introduced and its application to high temperature design problems is discussed briefly. (author).

  9. High temperature inorganic membranes for separating hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    1995-08-01

    Effort has continued to accumulate data on the transport of gases over the temperature range from room temperature to 275{degrees}C with inorganic membranes having a range of pore radii from approximately 0.25 nm to 3 mn. An experimental alumina membrane having an estimated mean pore radius of 0.25 nm has been fabricated and tested. Extensive testing of this membrane indicated that the separation factor for helium and carbon tetrafluoride at 250{degrees}C was 59 and the extrapolated high temperature separation factor was 1,193. For safety reasons, earlier flow measurements concentrated on helium, carbon dioxide, and carbon tetrafluoride. New data have been acquired with hydrogen to verify the agreement with the other gases. During the measurements with hydrogen, it was noted that a considerable amount of moisture was present in the test gas. The source of this moisture and its effect on permeance was examined. Improvements were implemented to the flow test system to minimize the water content of the hydrogen test gas, and subsequent flow measurements have shown excellent results with hydrogen. The extrapolation of separation factors as a function of temperature continues to show promise as a means of using the hard sphere model to determine the pore size of membranes. The temperature dependence of helium transport through membranes appears to be considerably greater than other gases for the smallest pore sizes. The effort to extend temperature dependence to the hard sphere model continues to be delayed, primarily because of a lack of adequate adsorption data.

  10. Novel High Temperature Magnetic Bearings for Space Vehicle Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Previous high temperature magnetic bearings employed electromagnets only. The work proposed in this SBIR program seeks to utilize High Temperature Permanent Magnets...

  11. Novel High Temperature Magnetic Bearings for Space Vehicle Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Previous high temperature magnetic bearings employed only electromagnets. The work proposed in this SBIR program seeks to utilize High Temperature Permanent Magnets...

  12. The NDT methods under high temperature service environment

    Directory of Open Access Journals (Sweden)

    Zhang Zhen-guo

    2016-01-01

    Full Text Available Concerning the detective requirement of the equipment under high temperature running status, this paper summarizes the technical characteristics and related applications of several non-destructive testing methods(NDT, such as thermal infrared imaging technology in high temperature, ultrasonic testing technique in high temperature, pulsed eddy current technology in high temperature and magnetic powder flaw detection technology in high temperature, penetration testing technique in high temperature and indirect visual detection in high temperature and on-line monitoring system in high temperature.

  13. Preparation of highly monodisperse fluorescent polymer particles by miniemulsion polymerization of styrene with a polymerizable surfactant.

    Science.gov (United States)

    Taniguchi, Tatsuo; Takeuchi, Naoki; Kobaru, Shotaro; Nakahira, Takayuki

    2008-11-01

    Miniemulsion polymerization of styrene (St) in the presence of a hydrophobe (hexadecane:HD) using a cationic polymerizable surfactant (N,N-dimethyl-N-n-dodecyl-N-2-methacryloyloxyethylammonium bromide:C(12)Br) and a cationic initiator (2,2'-azobis(2-amidinopropane) dihydrochloride:V50), called St/C(12)Br/V50 hereafter, proceeded efficiently compared with that using sodium dodecyl sulfate (SDS) and potassium persulfate (KPS), i.e., St/SDS/KPS, providing monodisperse polystyrene latex particles with a narrower particle size distribution. In St/C(12)Br/AIBN, where an oil-soluble initiator, i.e., 2,2'-azobisisobutyronitrile (AIBN), was used in place of V50, little changes in polymerization kinetics or in particle size distribution were observed, while a significant drop in polymerization rate and a broad particle size distribution were observed with St/SDS/AIBN. A polymerizable pyrene derivative (1-pyrenylmethyl methacrylate: PyMMA) was quantitatively incorporated into monodisperse latex particles in St/PyMMA/C(12)Br/V50 compared to pyrene (Py) in St/Py/C(12)Br/V50. Contrary to our expectation, however, increased excimer emission was observed with St/PyMMA/C(12)Br/V50 particles, indicating less evenly distributed pyrene chromophores in the particles. The fluorescence lifetime of pyrene chromophores in St/Py/C(12)Br/V50 particles was determined to be 286 ns, which was 17 times longer than that of pyrene in THF solution.

  14. Technology of high-temperature organic coolant

    Energy Technology Data Exchange (ETDEWEB)

    Vorobei, M.P.; Makin, R.S.; Kuprienko, V.A. [and others

    1993-12-31

    A wide range of studies were carried out in RIAR on the problems connected with the use of high-temperature organic coolant at nuclear power plants. The work performed and successful experience gained in persistent operation of the ARBUS reactor confirmed the inherent safety characteristics, high operational reliability, as well as improved safety of stations with similar reactors. A large scope of studies were carried out at the ARBUS pilot reactor and loop with the organic coolant of the MIR reactor and a wide range of problems were solved. The studies are described.

  15. Precipitation Hardenable High Temperature Shape Memory Alloy

    Science.gov (United States)

    Noebe, Ronald Dean (Inventor); Draper, Susan L. (Inventor); Nathal, Michael V. (Inventor); Crombie, Edwin A. (Inventor)

    2010-01-01

    A composition of the invention is a high temperature shape memory alloy having high work output, and is made from (Ni+Pt+Y),Ti(100-x) wherein x is present in a total amount of 49-55 atomic % Pt is present in a total amount of 10-30 atomic %, Y is one or more of Au, Pd. and Cu and is present in a total amount of 0 to 10 atomic %. The alloy has a matrix phase wherein the total concentration of Ni, Pt, and the one or more of Pd. Au, and Cu is greater than 50 atomic %.

  16. High Temperature Sensing Systems--Characteristics of Rechargeable Batteries at High Temperature--

    OpenAIRE

    2001-01-01

     High temperature discharge characteristics were measured at 100℃ for commercial available Nickel Cadmium and Nickel Metal Hydride rechargeable batteries. A Nickel Cadmium battery has superior dis­charge characteristics than a Nickel Metal Hydride battery. A life cycle of rechargeable battery can be esti­mated by measuring an internal resistance of the battery during charge at room temperature.

  17. Autoadhesion of High-Molecular-Weight Monodisperse Glassy Polystyrene at unexpected low temperatures

    DEFF Research Database (Denmark)

    Boiko, Yuri M.; Lyngaae-Jørgensen, Jørgen

    2004-01-01

    -bulk corresponding to a second-order phase transition temperature). To our knowledge, this is the first observation of such nature, which gives further evidence of the lowering of the T-g at polymeric surfaces and the persistence of this effect at early stages of healing of polymer-polymer interfaces.......Healing of symmetric interfaces of amorphous anionically polymerized high- and ultra-high-molecular weight (HMW and UHMW, respectively) polystyrene (PS) in a range of the weight-average molecular weight M-w from 102.5 (M-w/M-n = 1.05) to 1110 kg/ mol (M-w/M-n = 1.15) was followed at a constant...... healing temperature, T-h, well below the glass transition temperature of the polymer bulk [Tg-bulk = 105 - 106degreesC as measured by differential scanning calorimeter (DSC)]. The bonded interfaces were shear fractured in tension on an Instron tester at ambient temperature. Autoadhesion at symmetric HMW...

  18. High Temperature Materials for Chemical Propulsion Applications

    Science.gov (United States)

    Elam, Sandra; Hickman, Robert; O'Dell, Scott

    2007-01-01

    Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

  19. High temperature measurement of water vapor absorption

    Science.gov (United States)

    Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

    1985-01-01

    An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

  20. High-temperature alloys for high-power thermionic systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang S.; Jacobson, D.L.; D' cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  1. LHDAC setup for high temperature and high pressure studies

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Nishant N., E-mail: nnpatel@barc.gov.in; Meenakshi, S., E-mail: nnpatel@barc.gov.in; Sharma, Surinder M., E-mail: nnpatel@barc.gov.in [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    A ytterbium fibre laser (λ = 1.07 μm) based laser heated diamond anvil cell (LHDAC) facility has been recently set up at HP and SRPD, BARC for simultaneous high temperature and high pressure investigation of material properties. Synthesis of GaN was carried out at pressure of ∼9 GPa and temperature of ∼1925 K in a Mao-Bell type diamond anvil cell (DAC) using the LHDAC facility. The retrieved sample has been characterized using our laboratory based micro Raman setup.

  2. High-temperature brushless DC motor controller

    Energy Technology Data Exchange (ETDEWEB)

    Cieslewski, Crzegorz; Lindblom, Scott C.; Maldonado, Frank J.; Eckert, Michael Nathan

    2017-05-16

    A motor control system for deployment in high temperature environments includes a controller; a first half-bridge circuit that includes a first high-side switching element and a first low-side switching element; a second half-bridge circuit that includes a second high-side switching element and a second low-side switching element; and a third half-bridge circuit that includes a third high-side switching element and a third; low-side switching element. The motor controller is arranged to apply a pulse width modulation (PWM) scheme to switch the first half-bridge circuit, second half-bridge circuit, and third half-bridge circuit to power a motor.

  3. Conformal Properties in High Temperature QCD

    CERN Document Server

    Ishikawa, K -I; Nakayama, Yu; Yoshie, T

    2015-01-01

    We investigate the properties of quarks and gluons above the chiral phase transition temperature $T_c,$ using the RG improved gauge action and the Wilson quark action with two degenerate quarks mainly on a $32^3\\times 16$ lattice. In the one-loop perturbation theory, the thermal ensemble is dominated by the gauge configurations with effectively $Z(3)$ center twisted boundary conditions, making the thermal expectation value of the spatial Polyakov loop take a non-trivial $Z(3)$ center. This is in agreement with our lattice simulation of high temperature QCD. We further observe that the temporal propagator of massless quarks at extremely high temperature $\\beta=100.0 \\, (T \\simeq10^{58} T_c)$ remarkably agrees with the temporal propagator of free quarks with the $Z(3)$ twisted boundary condition for $t/L_t \\geq 0.2$, but differs from that with the $Z(3)$ trivial boundary condition. As we increase the mass of quarks $m_q$, we find that the thermal ensemble continues to be dominated by the $Z(3)$ twisted gauge fi...

  4. The NASA high temperature superconductivity program

    Science.gov (United States)

    Sokoloski, Martin M.; Romanofsky, Robert R.

    1990-01-01

    It has been recognized from the onset that high temperature superconductivity held great promise for major advances across a broad range of NASA interests. The current effort is organized around four key areas: communications and data, sensors and cryogenics, propulsion and power, and space materials technology. Recently, laser ablated YBa2Cu3O(7-x) films on LaAIO produced far superior RF characteristics when compared to metallic films on the same substrate. This achievement has enabled a number of unique microwave device applications, such as low insertion loss phase shifters and high Q filters. Melt texturing and melt quenched techniques are being used to produce bulk materials with optimized magnetic properties. These yttrium enriched materials possess enhanced flux pinning characteristics and will lead to prototype cryocooler bearings. Significant progress has also occurred in bolometer and current lead technology. Studies are being conducted to evaluate the effect of high temperature superconducting materials on the performance and life of high power magneto-plasma-dynamic thrusters. Extended studies were also performed to evaluate the benefit of superconducting magnetic energy storage for LEO space station, lunar and Mars mission applications. The project direction and level of effort of the program are also described.

  5. High Temperature Battery for Drilling Applications

    Energy Technology Data Exchange (ETDEWEB)

    Josip Caja

    2009-12-31

    In this project rechargeable cells based on the high temperature electrochemical system Na/beta''-alumina/S(IV) in AlCl3/NaCl were developed for application as an autonomous power source in oil/gas deep drilling wells. The cells operate in the temperature range from 150 C to 250 C. A prototype DD size cell was designed and built based on the results of finite element analysis and vibration testing. The cell consisted of stainless steel case serving as anode compartment with cathode compartment installed in it and a seal closing the cell. Critical element in cell design and fabrication was hermetically sealing the cell. The seal had to be leak tight, thermally and vibration stable and compatible with electrode materials. Cathode compartment was built of beta''-alumina tube which served as an electrolyte, separator and cathode compartment.

  6. Permanent magnets composed of high temperature superconductors

    Science.gov (United States)

    Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

    1991-01-01

    A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

  7. High-temperature insulation; Hochtemperatur-Waermeisolierung

    Energy Technology Data Exchange (ETDEWEB)

    Fuehres, M.

    1995-12-31

    For high-temperature insulations of industrial plants in the temperature range above 800 C preferably fibrous insulating materials are used. For this purpose ceramic fibres are more and more used. Apart from energy conservation possibilities up to 50% ceramic fibre products are characterized by a large field of the most different applications compared to conventional fire-resistant materials such as stone and compounds. The properties, production and the field of application are gone into in detail. (BWI) [Deutsch] In der Hochtemperaturisolierung industrieller Anlagen werden im Temperaturbereich oberhalb von 800 C bevorzugt faserfoermige Daemmstoffe eingesetzt. In zunehmendem Masse werden hierzu Keramikfasern eingesetzt. Neben den Einsparmoeglichkeiten im Energieverbrauch von bis zu 50% gegenueber konventionellen feuerfesten Werkstoffen wie Steinen und Massen zeichnen sich Keramikfaser-Produkte durch eine breite Palette vielfaeltigster Einsatzmoeglichkeiten aus. Es wird ausfuehrlich auf Eigenschaften, Herstellung und Einsatzmoeglichkeiten eingegangen. (BWI)

  8. Graphite thermal expansion reference for high temperature

    Science.gov (United States)

    Gaal, P. S.

    1974-01-01

    The design requirements of the aerospace and high-temperature nuclear reactor industries necessitate reliable thermal expansion data for graphite and other carbonaceous materials. The feasibility of an acceptable reference for calibration of expansion measuring systems that operate in carbon-rich atmospheres at temperatures ranging to 2500 C is the prime subject of this work. Present-day graphite technology provides acceptable materials for stable, reproducible references, as reflected by some of the candidate materials. The repeatability for a single specimen in a given expansion measuring system was found to be plus or minus 1%, while the combined results of several tests made on a number of samples fell within a plus or minus 2.5% band.

  9. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2017-01-31

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, copper, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  10. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2015-11-13

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6 carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  11. High temperature polymer electrolyte membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    K.Scott; M. Mamlouk

    2006-01-01

    One of the major issues limiting the introduction of polymer electrolyte membrane fuel cells (PEMFCs) is the low temperature of operation which makes platinum-based anode catalysts susceptible to poisoning by the trace amount of CO, inevitably present in reformed fuel. In order to alleviate the problem of CO poisoning and improve the power density of the cell, operating at temperature above 100 ℃ is preferred. Nafion(R) -type perfluorosulfonated polymers have been typically used for PEMFC. However, the conductivity of Nafion(R) -type polymers is not high enough to be used for fuel cell operations at higher temperature ( > 90 ℃) and atmospheric pressure because they dehydrate under these condition.An additional problem which faces the introduction of PEMFC technology is that of supplying or storing hydrogen for cell operation,especially for vehicular applications. Consequently the use of alternative fuels such as methanol and ethanol is of interest, especially if this can be used directly in the fuel cell, without reformation to hydrogen. A limitation of the direct use of alcohol is the lower activity of oxidation in comparison to hydrogen, which means that power densities are considerably lower. Hence to improve activity and power output higher temperatures of operation are preferable. To achieve this goal, requires a new polymer electrolyte membrane which exhibits stability and high conductivity in the absence of liquid water.Experimental data on a polybenzimidazole based PEMFC were presented. A simple steady-state isothermal model of the fuel cell is also used to aid in fuel cell performance optimisation. The governing equations involve the coupling of kinetic, ohmic and mass transport. This paper also considers the advances made in the performance of direct methanol and solid polymer electrolyte fuel cells and considers their limitations in relation to the source and type of fuels to be used.

  12. Kinetics of silica polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Weres, O.; Yee, A.; Tsao, L.

    1980-05-01

    The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.

  13. High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Turnquist, Norman [GE Global Research, Munchen (Germany); Qi, Xuele [GE Global Research, Munchen (Germany); Raminosoa, Tsarafidy [GE Global Research, Munchen (Germany); Salas, Ken [GE Global Research, Munchen (Germany); Samudrala, Omprakash [GE Global Research, Munchen (Germany); Shah, Manoj [GE Global Research, Munchen (Germany); Van Dam, Jeremy [GE Global Research, Munchen (Germany); Yin, Weijun [GE Global Research, Munchen (Germany); Zia, Jalal [GE Global Research, Munchen (Germany)

    2013-12-20

    This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

  14. Diamond based detectors for high temperature, high radiation environments

    Science.gov (United States)

    Metcalfe, A.; Fern, G. R.; Hobson, P. R.; Smith, D. R.; Lefeuvre, G.; Saenger, R.

    2017-01-01

    Single crystal CVD diamond has many desirable properties as a radiation detector; exceptional radiation hardness and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry and transmission mode applications), wide bandgap (high temperature operation with low noise and solar blind), an intrinsic pathway to fast neutron detection through the 12C(n,α)9Be reaction. This combination of radiation hardness, temperature tolerance and ability to detect mixed radiation types with a single sensor makes diamond particularly attractive as a detector material for harsh environments such as nuclear power station monitoring (fission and fusion) and oil well logging. Effective exploitation of these properties requires the development of a metallisation scheme to give contacts that remain stable over extended periods at elevated temperatures (up to 250°C in this instance). Due to the cost of the primary detector material, computational modelling is essential to best utilise the available processing methods for optimising sensor response through geometry and conversion media configurations and to fully interpret experimental data. Monte Carlo simulations of our diamond based sensor have been developed, using MCNP6 and FLUKA2011, assessing the sensor performance in terms of spectral response and overall efficiency as a function of the detector and converter geometry. Sensors with varying metallisation schemes for high temperature operation have been fabricated at Brunel University London and by Micron Semiconductor Limited. These sensors have been tested under a varied set of conditions including irradiation with fast neutrons and alpha particles at high temperatures. The presented study indicates that viable metallisation schemes for high temperature contacts have been successfully developed and the modelling results, supported by preliminary experimental data from partners, indicate that the simulations provide a reasonable representation of

  15. Fail Safe, High Temperature Magnetic Bearings

    Science.gov (United States)

    Minihan, Thomas; Palazzolo, Alan; Kim, Yeonkyu; Lei, Shu-Liang; Kenny, Andrew; Na, Uhn Joo; Tucker, Randy; Preuss, Jason; Hunt, Andrew; Carter, Bart; hide

    2002-01-01

    This paper contributes to the magnetic bearing literature in two distinct areas: high temperature and redundant actuation. Design considerations and test results are given for the first published combined 538 C (1000 F) high speed rotating test performance of a magnetic bearing. Secondly, a significant extension of the flux isolation based, redundant actuator control algorithm is proposed to eliminate the prior deficiency of changing position stiffness after failure. The benefit of the novel extension was not experimentally demonstrated due to a high active stiffness requirement. In addition, test results are given for actuator failure tests at 399 C (750 F), 12,500 rpm. Finally, simulation results are presented confirming the experimental data and validating the redundant control algorithm.

  16. A High-Fidelity Codon Set for the T4 DNA Ligase-Catalyzed Polymerization of Modified Oligonucleotides.

    Science.gov (United States)

    Lei, Yi; Kong, Dehui; Hili, Ryan

    2015-12-14

    In vitro selection of nucleic acid polymers can readily deliver highly specific receptors and catalysts for a variety of applications; however, it is suspected that the functional group deficit of nucleic acids has limited their potential with respect to proteinogenic polymers. This has stimulated research toward expanding their chemical diversity to bridge the functional gap between nucleic acids and proteins to develop a superior biopolymer. In this study, we investigate the effect of codon library size and composition on the sequence specificity of T4 DNA ligase in the DNA-templated polymerization of both unmodified and modified oligonucleotides. Using high-throughput DNA sequencing of duplex pairs, we have uncovered a 256-membered codon set that yields sequence-defined modified ssDNA polymers in high yield and with high fidelity.

  17. High-temperature superconductors make major progress

    CERN Multimedia

    CERN Bulletin

    2014-01-01

    This month's Nature Materials featured an important breakthrough for high-temperature superconductors. A new method has been found for processing Bi-2212 high-temperature superconducting round wire in order to drastically increase its critical current density. The result confirms that this conductor is a serious candidate for future very-high-field magnets.   This image shows the cross-section of two Bi-2212 wires. The bottom wire has less leakage and void porosity due to a heat treatment done at an overpressure of 100 bar - about 100 times the pressure used to produce the top wire (image from [Nature Materials, Vol. 13 (2014), 10.1038/nmat3887]). The workhorse for building superconducting accelerator magnets has been, so far, the Niobium-Titanium (Nb-Ti) alloy superconductor. But with Nb-Ti having reached its full potential, other conductors must be used to operate in higher magnetic fields beyond those reached with the LHC magnets. Today, the intermetallic Niobium-Tin (Nb3Sn) is th...

  18. High temperature flat plate solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Hozumi, S.; Aso, S.; Ebisu, K.; Uchino, H.

    1981-04-01

    Improvements in the efficiency of collectors are of great importance for extending the utilization of solar energy for heating and cooling in homes. A highly efficient collector makes the system size small and decreases the system cost effectively. From the view of the amount of energy collected, the efficient collector has a multiple effect, not only because of the high increase in instantaneous efficiency, but also because of the large usable intensity range of the insolation. On the basis of a functional analysis for a flat collector, the materials and parameters were selected and optimized, and a new high temperature flat collector was designed. The collector has 2 panes. The first pane is low iron glass and the second pane is a thin film of fluorinated ethylene-propylene copolymer. The overall solar transmittance for the two panes is 0.89. The collecting panel and its water paths were formed by means of welding and hydraulic expansion. The selective absorbing surface consists of colored stainless steel whose absorption characteristic is 0.89 and emission characteristic is 0.16. The thermal insulator preventing backward heatloss consists of double layers of urethane foam and glass wool. Furthermore, the sustained method for the second pane is contrived so as to prevent water condensation on the panes and excessive elevation of the absorber temperature during no load heating.

  19. Robust high temperature oxygen sensor electrodes

    DEFF Research Database (Denmark)

    Lund, Anders

    Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode ......-based electrodes and one porous electrode based on the perovskite-structured strontium and vanadiumdoped lanthanum chromium oxide (LSCV) were investigated. The porous electrodes were applied on yttrium-stabilised zirconium oxide (YSZ) substrates in a collaboration with the company PBI...

  20. High Temperature Sodium Thermal Convection Test Loop

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A project for the evaluation of compatibility characteristic of structural materials used in China experimental fast reactor(CEFR) has been in operation. The conditions which these structural materials contact with liquid sodium in reactor can be simulated by the tests in high temperature sodium thermal convection test loop. The main aims of designing and constructing the thermal convection test loop is for the corrosion test of CEFR materials, and the objective is to obtain the corrosion data of domestic materials.The main features of the test loop are shown in Fig.1. The primary components of the loop

  1. Applications of bulk high-temperature superconductors

    Science.gov (United States)

    Hull, J. R.

    The development of high-temperature superconductors (HTS's) can be broadly generalized into thin-film electronics, wire applications, and bulk applications. We consider bulk HTS's to include sintered or crystallized forms that do not take the geometry of filaments or tapes, and we discuss major applications for these materials. For the most part applications may be realized with the HTS's cooled to 77 K, and the properties of the bulk HTS's are often already sufficient for commercial use. A non-exhaustive list of applications for bulk HTS's includes trapped field magnets, hysteresis motors, magnetic shielding, current leads, and magnetic bearings. These applications are briefly discussed in this paper.

  2. High Temperature Corrosion in Biomass Incineration Plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel; Gotthjælp, K.

    1997-01-01

    The aim of the project is to study the role of ash deposits in high temperature corrosion of superheater materials in biomass and refuse fire combined heat and power plants. The project has included the two main activities: a) A chemical characterisation of ash deposits collected from a major...... number of biomass and refuse fired combined heat and power plant boilers, b) Laboratory exposures and metallurgical examinations of material specimens with ash deposits in well-defined gas environments with HCl and SO2 in a furnace....

  3. High Temperature Materials Laboratory third annual report

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Foust, F.M.

    1990-12-01

    The High Temperature Materials Laboratory has completed its third year of operation as a designated DOE User Facility at the Oak Ridge National Laboratory. Growth of the user program is evidenced by the number of outside institutions who have executed user agreements since the facility began operation in 1987. A total of 88 nonproprietary agreements (40 university and 48 industry) and 20 proprietary agreements (1 university, 19 industry) are now in effect. Sixty-eight nonproprietary research proposals (39 from university, 28 from industry, and 1 other government facility) and 8 proprietary proposals were considered during this reporting period. Research projects active in FY 1990 are summarized.

  4. High temperature quark localization by Polyakov loops

    CERN Document Server

    Kovacs, Tamas G; Bruckmann, Falk; Schierenberg, Sebastian

    2011-01-01

    We study the low eigenmodes of the overlap and staggered Dirac operator at high temperature. We show that the recently found localized quark modes obeying Poisson statistics are connected to physical gauge field objects with their size and density scaling in the continuum limit. The localized modes are also strongly correlated with large fluctuations of the Polyakov loop. Based on that we construct a random matrix model of the low Dirac modes inspired by dimensional reduction. Our model reproduces the Poisson to random matrix transition seen in the lattice Dirac spectrum.

  5. Symmetry Non-restoration at High Temperature

    CERN Document Server

    Rius, N

    1998-01-01

    We discuss the (non)-restoration of global and local symmetries at high temperature. First, we analyze a two-scalar model with $Z_2 \\times Z_2$ symmetry using the exact renormalization group. We conclude that inverse symmetry breaking is possible in this kind of models within the perturbative regime. Regarding local symmetries, we consider the $SU(2) \\otimes U(1)$ gauge symmetry and focus on the case of a strongly interacting scalar sector. Employing a model-independent chiral Lagrangian we find indications of symmetry restoration.

  6. High temperature decomposition of hydrogen peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  7. Aerospace applications of high temperature superconductivity

    Science.gov (United States)

    Heinen, V. O.; Connolly, D. J.

    1991-01-01

    Space application of high temperature superconducting (HTS) materials may occur before most terrestrial applications because of the passive cooling possibilities in space and because of the economic feasibility of introducing an expensive new technology which has a significant system benefit in space. NASA Lewis Research Center has an ongoing program to develop space technology capitalizing on the potential benefit of HTS materials. The applications being pursued include space communications, power and propulsion systems, and magnetic bearings. In addition, NASA Lewis is pursuing materials research to improve the performance of HTS materials for space applications.

  8. High-temperature superconducting current leads

    Science.gov (United States)

    Hull, J. R.

    1992-07-01

    The use of high-temperature superconductors (HTSs) for current leads to deliver power to devices at liquid helium temperature is near commercial realization. The use of HTSs in this application has the potential to reduce refrigeration requirements and helium boiloff to values significantly lower than the theoretical best achievable with conventional leads. Considerable advantage is achieved by operating these leads with an intermediate temperature heat sink. The HTS part of the lead can be made from pressed and sintered powder. Powder-in-tube fabrication is also possible, however, the normal metal part of the lead acts as a thermal short and cannot provide much stabilization without increasing the refrigeration required. Lead stability favors designs with low current density. Such leads can be manufactured with today's technology, and lower refrigeration results from the same allowable burnout time. Higher current densities result in lower boiloff for the same lead length, but bumout times can be very short. In comparing experiment to theory, the density of helium vapor needs to be accounted for in calculating the expected boiloff. For very low-loss leads, two-dimensional heat transfer and the state of the dewar near the leads may play a dominant role in lead performance.

  9. Simple efficient synthesis of strongly luminescent polypyrene with intrinsic conductivity and high carbon yield by chemical oxidative polymerization of pyrene.

    Science.gov (United States)

    Li, Xin-Gui; Liu, You-Wei; Huang, Mei-Rong; Peng, Sai; Gong, Ling-Zhi; Moloney, Mark G

    2010-04-26

    A wholly aromatic polypyrene was synthesized by direct chemical oxidative polymerization of pyrene with ferric chloride as oxidant in hexane/nitromethane. Successful synthesis of polypyrene was thoroughly confirmed by IR, UV/Vis, 1D (1)H NMR, 2D (1)H-(1)H COSY, 2D (1)H-(13)C HSQC, MALDI-TOF MS, elemental analysis, and X-ray diffraction methods. The results indicated that the polypyrene was formed mainly through dehydro coupling between 2- or 1- and 2'- or 1'-positions on pyrene rings having a degree of polymerization of around 24. The polypyrene was purified and then separated into THF-soluble (ca. 10 %) and THF-insoluble (ca. 90 %) fractions. Compared with insulating pyrene monomer, the polypyrene is a controllably conducting polymer that has low conductivity of 3.4x10(-8) S cm(-1) in its virgin state, moderate conductivity of 2.28x10(-4) S cm(-1) upon iodine doping, but much higher conductivity of up to 81.2 S cm(-1) after the insoluble polypyrene was heated up to 1300 degrees C in nitrogen with a high char yield of 70.6 %. In particular, the soluble polypyrene demonstrates much stronger visible color fluorescence and much lower toxicity than pyrene. The soluble polypyrene would be advantageous for detecting Fe(3+) with almost no interference of other metal ions. The soluble and insoluble polypyrene fractions have potential applications as intrinsically luminescent and highly conducting carbon materials, respectively.

  10. Establishing a High-content Analysis Method for Tubulin Polymerization to Evaluate Both the Stabilizing and Destabilizing Activities of Compounds.

    Science.gov (United States)

    Sum, Chi Shing; Nickischer, Debra; Lei, Ming; Weston, Andrea; Zhang, Litao; Schweizer, Liang

    2014-01-01

    Microtubules are important components of the cellular cytoskeleton that play roles in various cellular processes such as vesicular transport and spindle formation during mitosis. They are formed by an ordered organization of α-tubulin and β-tubulin hetero-polymers. Altering microtubule polymerization has been known to be the mechanism of action for a number of therapeutically important drugs including taxanes and epothilones. Traditional cell-based assays for tubulin-interacting compounds rely on their indirect effects on cell cycle and/or cell proliferation. Direct monitoring of compound effects on microtubules is required to dissect detailed mechanisms of action in a cellular setting. Here we report a high-content assay platform to monitor tubulin polymerization status by directly measuring the acute effects of drug candidates on the cellular tubulin network with the capability to dissect the mechanisms of action. This high-content analysis distinguishes in a quantitative manner between compounds that act as tubulin stabilizers versus those that are tubulin destabilizers. In addition, using a multiplex approach, we expanded this analysis to simultaneously monitor physiological cellular responses and associated cellular phenotypes.

  11. Intercalated Nanocomposites Based on High-Temperature Superconducting Ceramics and Their Properties

    Directory of Open Access Journals (Sweden)

    Sevan Davtyan

    2009-12-01

    Full Text Available High temperature superconducting (SC nanocomposites based on SC ceramics and various polymeric binders were prepared. Regardless of the size of the ceramics’ grains, the increase of their amount leads to an increase of resistance to rupture and modulus and a decrease in limiting deformation, whereas an increase in the average ceramic grain size worsens resistance properties. The SC, thermo-chemical, mechanical and dynamic-mechanical properties of the samples were investigated. Superconducting properties of the polymer ceramic nanocomposites are explained by intercalation of macromolecule fragments into the interstitial layer of the ceramics’ grains. This phenomenon leads to a change in the morphological structure of the superconducting nanocomposites.

  12. Predicted novel metallic metastable phases of polymeric nitrogen at high pressures

    Science.gov (United States)

    Wang, Xiaoli; Tian, Fubo; Wang, Lin; Jin, Xilian; Duan, Defang; Huang, Xiaoli; Liu, Bingbing; Cui, Tian

    2013-01-01

    Two new metallic polymeric structures of nitrogen, Pnnm and Cccm, are found by means of the first-principles density functional theory and a random structure-searching method. Firstly, it is shown that the transition behavior of nitrogen from insulator to metal starts at a pressure of approximately 460 GPa at 0 K. The Pnnm phase becomes energetically favorable with respect to cubic gauche at 363 GPa, and then transforms to the Cccm structure at 884 GPa. Electron-phonon coupling calculations suggest that the Pnnm crystal possesses superconductivity. The stability of these two phases is also explored, showing for the first time that they are stable structures of nitrogen exhibiting metallic properties.

  13. High power densities from high-temperature material interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.F.

    1981-01-01

    Thermionic energy conversion (TEC) and metallic-fluid heat pipes (MFHPs) offer important and unique advantages in terrestrial and space energy processing. And they are well suited to serve together synergistically. TEC and MFHPs operate through working-fluid vaporization, condensation cycles that accept great thermal power densities at high temperatures. TEC and MFHPs have apparently simple, isolated performance mechanisms that are somewhat similar. And they also have obviously difficult, complected material problems that again are somewhat similar. Intensive investigation reveals that aspects of their operating cycles and material problems tend to merge: high-temperature material effects determine the level and lifetime of performance. Simplified equations verify the preceding statement for TEC and MFHPs. Material properties and interactions exert primary influences on operational effectiveness. And thermophysicochemical stabilities dictate operating temperatures which regulate the thermoemissive currents of TEC and the vaporization flow rates of MFHPs. Major high-temperature material problems of TEC and MFHPs have been solved. These solutions lead to productive, cost-effective applications of current TEC and MFHPs - and point to significant improvements with anticipated technological gains.

  14. A facile and simple high-performance polydimethylsiloxane casting based on self-polymerization dopamine

    Science.gov (United States)

    Chen, Xing; Zhang, Lu-lu; Sun, Jian-hai; Li, Hui; Cui, Da-fu

    2014-09-01

    We present a new and facile method for polydimethylsiloxane (PDMS) casting by dip-coating the master molds in an aqueous solution of dopamine. A poly(dopamine) film formed by self-polymerization of dopamine is used as the surface anti-adhesion coating for PDMS de-molding. Different master molds, such as metal, silicon and PDMS replica, were used to verify the feasibility of this proposed PDMS casting method. The poly(dopamine) coatings at various fabrication conditions were studied by using surface plasmon resonance technology. We found that it is very easy to form repeated poly(dopamine) coatings with similar thicknesses and density at fairly flexible conditions of self-polymerization. The water contact angles of the PDMS master molds and the positive PDMS replicas were studied after the PDMS master molds were immersed in the dopamine coating solution for different times. The de-molding process was then measured by surface plasmon resonance technology. The surface morphology of the master molds and the PDMS replicas were characterized by using scanning electron microscopy and atomic force microscopy. Results demonstrate that the poly(dopamine) coating exhibits a strong release property in the PDMS de-molding process and has good stickiness after PDMS de-molding a dozen times. The package performances of the PDMS replicas were detected and compared by bonding experiments. PDMS replicas after a second round of de-molding present a little higher package performance than that of the PDMS replicas with an anti-sticking agent of silane. The biochemical properties of PDMS replicas were studied through fluorescence immunoassay experiments. The PDMS replicas present similar biochemical properties to the bare PDMS. This biomimetic surface modification method of dopamine for PDMS casting has a great potential for preparing microdevices for various biological and clinical applications.

  15. High point for CERN and high-temperature superconductors

    CERN Multimedia

    2007-01-01

    Amalia Ballarino is named the Superconductor Industry Person of the year 2006. Amalia Ballarino showing a tape of high-superconducting material used for the LHC current leads.The CERN project leader for the high-temperature superconducting current leads for the LHC, Amalia Ballarino, has received the award for "Superconductor Industry Person of the Year". This award, the most prestigious international award in the development and commercialization of superconductors, is presented by the leading industry newsletter "Superconductor Week". Amalia Ballarino was selected from dozens of nominations from around the world by a panel of recognized leading experts in superconductivity. "It is a great honour for me," says Amalia Ballarino. "It has been many years of hard work, and it’s a great satisfaction to see that the work has been completed successfully." Amalia Ballarino has been working on high-temperature superconducting materials sin...

  16. High-Temperature, High-Load-Capacity Radial Magnetic Bearing

    Science.gov (United States)

    Provenza, Andrew; Montague, Gerald; Kascak, Albert; Palazzolo, Alan; Jansen, Ralph; Jansen, Mark; Ebihara, Ben

    2005-01-01

    A radial heteropolar magnetic bearing capable of operating at a temperature as high as 1,000 F (=540 C) has been developed. This is a prototype of bearings for use in gas turbine engines operating at temperatures and speeds much higher than can be withstood by lubricated rolling-element bearings. It is possible to increase the maximum allowable operating temperatures and speeds of rolling-element bearings by use of cooling-air systems, sophisticated lubrication systems, and rotor-vibration- damping systems that are subsystems of the lubrication systems, but such systems and subsystems are troublesome. In contrast, a properly designed radial magnetic bearing can suspend a rotor without contact, and, hence, without need for lubrication or for cooling. Moreover, a magnetic bearing eliminates the need for a separate damping system, inasmuch as a damping function is typically an integral part of the design of the control system of a magnetic bearing. The present high-temperature radial heteropolar magnetic bearing has a unique combination of four features that contribute to its suitability for the intended application: 1. The wires in its electromagnet coils are covered with an insulating material that does not undergo dielectric breakdown at high temperature and is pliable enough to enable the winding of the wires to small radii. 2. The processes used in winding and potting of the coils yields a packing factor close to 0.7 . a relatively high value that helps in maximizing the magnetic fields generated by the coils for a given supplied current. These processes also make the coils structurally robust. 3. The electromagnets are of a modular C-core design that enables replacement of components and semiautomated winding of coils. 4. The stator is mounted in such a manner as to provide stable support under radial and axial thermal expansion and under a load as large as 1,000 lb (.4.4 kN).

  17. Apparatus for accurately measuring high temperatures

    Science.gov (United States)

    Smith, D.D.

    The present invention is a thermometer used for measuring furnace temperatures in the range of about 1800/sup 0/ to 2700/sup 0/C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  18. Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  19. Thermomechanics of composite structures under high temperatures

    CERN Document Server

    Dimitrienko, Yu I

    2016-01-01

    This pioneering book presents new models for the thermomechanical behavior of composite materials and structures taking into account internal physico-chemical transformations such as thermodecomposition, sublimation and melting at high temperatures (up to 3000 K). It is of great importance for the design of new thermostable materials and for the investigation of reliability and fire safety of composite structures. It also supports the investigation of interaction of composites with laser irradiation and the design of heat-shield systems. Structural methods are presented for calculating the effective mechanical and thermal properties of matrices, fibres and unidirectional, reinforced by dispersed particles and textile composites, in terms of properties of their constituent phases. Useful calculation methods are developed for characteristics such as the rate of thermomechanical erosion of composites under high-speed flow and the heat deformation of composites with account of chemical shrinkage. The author expan...

  20. High-Temperature Ionization in Protoplanetary Disks

    CERN Document Server

    Desch, Steven J

    2015-01-01

    We calculate the abundances of electrons and ions in the hot (> 500 K), dusty parts of protoplanetary disks, treating for the first time the effects of thermionic and ion emission from the dust grains. High-temperature ionization modeling has involved simply assuming that alkali elements such as potassium occur as gas-phase atoms and are collisionally ionized following the Saha equation. We show that the Saha equation often does not hold, because free charges are produced by thermionic and ion emission and destroyed when they stick to grain surfaces. This means the ionization state depends not on the first ionization potential of the alkali atoms, but rather on the grains' work functions. The charged species' abundances typically rise abruptly above about 800 K, with little qualitative dependence on the work function, gas density, or dust-to-gas mass ratio. Applying our results, we find that protoplanetary disks' dead zone, where high diffusivities stifle magnetorotational turbulence, has its inner edge locat...

  1. Filter unit for use at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ciliberti, D.F.; Lippert, T.E.

    1988-04-05

    A filtering unit for the filtering of particulates from a particulate-containing high temperature gas stream is described comprising a ceramic, tubular filter element, having a closed bottom and side walls and an open top at the upper region thereof, disposed in an aperture in a tube sheet. The walls of the tube sheet about the aperature have an inwardly extending flange thereon, with the open top of the ceramic, tubular filter element adjacent one surface of the tube sheet where filtered gases are discharged, and the closed bottom and side walls exposed to the area of the opposite surface of the tube sheet where a particulate-containing high temperature gas stream to be filtered is present. A ceramic spiral spring is provided at an end of the ceramic, tubular filter element to bias the upper region of the ceramic, tubular filter element into contact with the flange so as to seal the ceramic, tubular filter element to the flange on the tube sheet.

  2. Finite element analysis of the high strain rate testing of polymeric materials

    Science.gov (United States)

    Gorwade, C. V.; Alghamdi, A. S.; Ashcroft, I. A.; Silberschmidt, V. V.; Song, M.

    2012-08-01

    Advanced polymer materials are finding an increasing range of industrial and defence applications. Ultra-high molecular weight polymers (UHMWPE) are already used in lightweight body armour because of their good impact resistance with light weight. However, a broader use of such materials is limited by the complexity of the manufacturing processes and the lack of experimental data on their behaviour and failure evolution under high-strain rate loading conditions. The current study deals with an investigation of the internal heat generation during tensile of UHMWPE. A 3D finite element (FE) model of the tensile test is developed and validated the with experimental work. An elastic-plastic material model is used with adiabatic heat generation. The temperature and stresses obtained with FE analysis are found to be in a good agreement with the experimental results. The model can be used as a simple and cost effective tool to predict the thermo-mechanical behaviour of UHMWPE part under various loading conditions.

  3. Transformation pathways in high-pressure solid nitrogen: from molecular N$_2$ to polymeric cg-N

    CERN Document Server

    Plašienka, Dusan

    2014-01-01

    The transition pathway in high-pressure solid nitrogen from N$_2$ molecular state to polymeric cg-N phase was investigated by means of \\textit{ab initio} molecular dynamics and metadynamics simulations. In our study, we observed a transformation mechanism from molecular $Immm$ phase initiated by formation of $trans$-$cis$ chains. These chains further connected within layers and formed a chain-planar state, which we describe as a mixture of crystalline $trans$-$cis$ chain phase and $planar$ phase (both with $Pnma$ symmetry). This form appeared in molecular dynamics performed at 120 GPa and 1500 K and also in metadynamics run at 110 GPa and 1500 K, in which the chains continued to reorganize further and finally formed cg-N. During various other metadynamics runs, two different phases emerged - molecular $P2_1/c$ and two-three-coordinated chain-like $Cm$. The transformation mechanism leading to cg-N may be characterized as a progressive polymerization process passing throughout several intermediate states of var...

  4. Highly Stereoselective Heterogeneous Diene Polymerization by Co-MFU-4l: A Single-Site Catalyst Prepared by Cation Exchange.

    Science.gov (United States)

    Dubey, Romain J-C; Comito, Robert J; Wu, Zhenwei; Zhang, Guanghui; Rieth, Adam J; Hendon, Christopher H; Miller, Jeffrey T; Dincă, Mircea

    2017-09-13

    Molecular catalysts offer tremendous advantages for stereoselective polymerization because their activity and selectivity can be optimized and understood mechanistically using the familiar tools of organometallic chemistry. Yet, this exquisite control over selectivity comes at an operational price that is generally not justifiable for the large-scale manufacture of polyfolefins. In this report, we identify Co-MFU-4l, prepared by cation exchange in a metal-organic framework, as a solid catalyst for the polymerization of 1,3-butadiene with high stereoselectivity (>99% 1,4-cis). To our knowledge, this is the highest stereoselectivity achieved with a heterogeneous catalyst for this transformation. The polymer's low polydispersity (PDI ≈ 2) and the catalyst's ready recovery and low leaching indicate that our material is a structurally resilient single-site heterogeneous catalyst. Further characterization of Co-MFU-4l by X-ray absorption spectroscopy provided evidence for discrete, tris-pyrazolylborate-like coordination of Co(II). With this information, we identify a soluble cobalt complex that mimics the structure and reactivity of Co-MFU-4l, thus providing a well-defined platform for studying the catalytic mechanism in the solution phase. This work underscores the capacity for small molecule-like tunability and mechanistic tractability available to transition metal catalysis in metal-organic frameworks.

  5. High density and high temperature plasmas in Large Helical Device

    Science.gov (United States)

    Komori, Akio

    2010-11-01

    Recently a new confinement regime called Super Dense Core (SDC) mode was discovered in Large Helical Device (LHD). An extremely high density core region with more than ~ 1 × 1021 m-3 is obtained with the formation of an Internal Diffusion Barrier (IDB). The density gradient at the IDB is very high and the particle confinement in the core region is ~ 0.2 s. It is expected, for the future reactor, that the IDB-SDC mode has a possibility to achieve the self-ignition condition with lower temperature than expected before. Conventional approaches to increase the temperature have also been tried in LHD. For the ion heating, the perpendicular neutral beam injection effectively increased the ion temperature up to 5.6 keV with the formation of the internal transport barrier (ITB). In the electron heating experiments with 77 GHz gyrotrons, the highest electron temperature more than 15 keV was achieved, where plasmas are in the neoclassical regime.

  6. High density and high temperature plasmas in Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Komori, Akio, E-mail: komori@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)

    2010-11-01

    Recently a new confinement regime called Super Dense Core (SDC) mode was discovered in Large Helical Device (LHD). An extremely high density core region with more than {approx} 1 x 10{sup 21} m{sup -3} is obtained with the formation of an Internal Diffusion Barrier (IDB). The density gradient at the IDB is very high and the particle confinement in the core region is {approx} 0.2 s. It is expected, for the future reactor, that the IDB-SDC mode has a possibility to achieve the self-ignition condition with lower temperature than expected before. Conventional approaches to increase the temperature have also been tried in LHD. For the ion heating, the perpendicular neutral beam injection effectively increased the ion temperature up to 5.6 keV with the formation of the internal transport barrier (ITB). In the electron heating experiments with 77 GHz gyrotrons, the highest electron temperature more than 15 keV was achieved, where plasmas are in the neoclassical regime.

  7. High temperature and current density induced degradation of multi-layer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Baoming; Haque, M. A., E-mail: mah37@psu.edu [Mechanical and Nuclear Engineering, The Pennsylvania State University, 314, Leonhard Building, University Park, Pennsylvania 16802 (United States); Mag-isa, Alexander E.; Kim, Jae-Hyun [Korea Institute of Machinery and Materials, 156 Gajungbuk-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Lee, Hak-Joo [Korea Institute of Machinery and Materials, 156 Gajungbuk-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Center for Advanced Meta-Materials (CAMM), 156 Gajungbuk-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of)

    2015-10-19

    We present evidence of moderate current density, when accompanied with high temperature, promoting migration of foreign atoms on the surface of multi-layer graphene. Our in situ transmission electron microscope experiments show migration of silicon atoms at temperatures above 800 °C and current density around 4.2 × 10{sup 7} A/cm{sup 2}. Originating from the micro-machined silicon structures that clamp the freestanding specimen, the atoms are observed to react with the carbon atoms in the multi-layer graphene to produce silicon carbide at temperatures of 900–1000 °C. In the absence of electrical current, there is no migration of silicon and only pyrolysis of polymeric residue is observed.

  8. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    1996-08-01

    Ceramic gas separation membranes can provide very high separation factors if the pore size is sufficiently small to separate gas molecules by molecular sieving and if oversized pores are adequately limited. Ceramic membranes typically have some pores that are substantially larger than the mean pore size and that should be regarded as defects. To assess the effects of such defects on the performance of ceramic membranes, a simple mathematical model has been developed to describe flow through a gas separation membrane that has a primary mode of flow through very small pores but that has a secondary mode of flow through undesirably large pores. This model permits separation factors to be calculated for a specified gas pair as a function of the molecular weights and molecular diameters of the gases, the membrane pore diameter, and the diameter and number of defects. This model will be described, and key results from the model will be presented. The separation factors of the authors membranes continue to be determined using a permeance test system that measures flows of pure gases through a membrane at temperatures up to 275{degrees}C. A primary goal of this project for FY 1996 is to develop a mixed gas separation system for measuring the separation efficiency of membranes at higher temperatures. Performance criteria have been established for the planned mixed gas separation system and design of the system has been completed. The test system is designed to measure the separation efficiency of membranes at temperatures up to 600{degrees}C and pressures up to 100 psi by separating the constituents of a gas mixture containing hydrogen. The system will accommodate the authors typical experimental membrane that is tubular and has a diameter of about 9 mm and a length of about 23 cm. The design of the new test system and its expected performance will be discussed.

  9. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  10. Potential aerospace applications of high temperature superconductors

    Science.gov (United States)

    Selim, Raouf

    1994-01-01

    The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on

  11. Porous and Magnetic Molecularly Imprinted Polymers via Pickering High Internal Phase Emulsions Polymerization for Selective Adsorption of λ-Cyhalothrin

    Science.gov (United States)

    Wu, Yunlong; Ma, Yue; Pan, Jianming; Gu, Runxing; Luo, Jialu

    2017-01-01

    A novel macroporous magnetic molecularly imprinted polymer (MMIPs) of was prepared by W/O Pickering (high internal phase emulsions) HIPEs polymerization, and then it was adopted as adsorbent for selective adsorption of λ-cyhalothrin (LC). In static conditions, adsorption capacity of LC increased rapidly in the first 60 min and reached to equilibrium in ~2.0 h. Excellent conformity of the second-order model confirmed the chemical nature of the interaction between the LC and imprinted sites. The fitting adsorption isotherm was a Langmuir type, and the maximum monolayer adsorption capacity at 298 K was 404.4 μmol g−1. Thermodynamic parameters suggested the specific adsorption at 298 K was an exothermic, spontaneous, and entropy decreased process. Competitive recognition studies of the MMIPs were performed with diethyl phthalate (DEP) and the structurally similar compound fenvalerate (FL), and the MMIPs, which displayed high selectivity for LC.

  12. High pressure/high temperature thermogravimetric apparatus. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.; Suuberg, E.M.

    1999-12-01

    The purpose of this instrumentation grant was to acquire a state-of-the-art, high pressure, high temperature thermogravimetric apparatus (HP/HT TGA) system for the study of the interactions between gases and carbonaceous solids for the purpose of solving problems related to coal utilization and applications of carbon materials. The instrument that we identified for this purpose was manufactured by DMT (Deutsche Montan Technologies)--Institute of Cokemaking and Coal Chemistry of Essen, Germany. Particular features of note include: Two reactors: a standard TGA reactor, capable of 1100 C at 100 bar; and a high temperature (HT) reactor, capable of operation at 1600 C and 100 bar; A steam generator capable of generating steam to 100 bar; Flow controllers and gas mixing system for up to three reaction gases, plus a separate circuit for steam, and another for purge gas; and An automated software system for data acquisition and control. The HP/TP DMT-TGA apparatus was purchased in 1996 and installed and commissioned during the summer of 1996. The apparatus was located in Room 128 of the Prince Engineering Building at Brown University. A hydrogen alarm and vent system were added for safety considerations. The system has been interfaced to an Ametek quadruple mass spectrometer (MA 100), pumped by a Varian V250 turbomolecular pump, as provided for in the original proposed. With this capability, a number of gas phase species of interest can be monitored in a near-simultaneous fashion. The MS can be used in a few different modes. During high pressure, steady-state gasification experiments, it is used to sample, measure, and monitor the reactant/product gases. It can also be used to monitor gas phase species during nonisothermal temperature programmed reaction (TPR) or temperature programmed desorption (TPD) experiments.

  13. High-temperature superconducting undulator magnets

    Science.gov (United States)

    Kesgin, Ibrahim; Kasa, Matthew; Ivanyushenkov, Yury; Welp, Ulrich

    2017-04-01

    This paper presents test results on a prototype superconducting undulator magnet fabricated using 15% Zr-doped rare-earth barium copper oxide high temperature superconducting (HTS) tapes. On an 11-pole magnet we demonstrate an engineering current density, J e, of more than 2.1 kA mm‑2 at 4.2 K, a value that is 40% higher than reached in comparable devices wound with NbTi-wire, which is used in all currently operating superconducting undulators. A novel winding scheme enabling the continuous winding of tape-shaped conductors into the intricate undulator magnets as well as a partial interlayer insulation procedure were essential in reaching this advance in performance. Currently, there are rapid advances in the performance of HTS; therefore, achieving even higher current densities in an undulator structure or/and operating it at temperatures higher than 4.2 K will be possible, which would substantially simplify the cryogenic design and reduce overall costs.

  14. A polymerized C60 coating enhancing interfacial stability at three-dimensional LiCoO2 in high-potential regime

    Science.gov (United States)

    Hudaya, Chairul; Halim, Martin; Pröll, Johannes; Besser, Heino; Choi, Wonchang; Pfleging, Wilhelm; Seifert, Hans Jürgen; Lee, Joong Kee

    2015-12-01

    The interfacial instabilities, including side reactions due to electrolyte decompositions and Cobalt (Co) dissolutions, are the main detrimental processes at LiCoO2 cathode when a high-voltage window (>4.2 V) is applied. Nevertheless, cycling the cathode with a voltage above 4.2 V would deliver an increased gravimetric capacity, which is desired for high power battery operation. To address these drawbacks, we demonstrate a synergistic approach by manufacturing the three-dimensional high-temperature LiCoO2 electrodes (3D HT-LCO) using laser-microstructuring, laser-annealing and subsequent coating with polymerized C60 thin films (C60@3D HT-LCO) by plasma-assisted thermal evaporation. The C60@3D HT-LCO cathode delivers higher initial discharge capacity compared to its theoretical value, i.e. 175 mA h g-1 at 0.1 C with cut-off voltage of 3.0-4.5 V. This cathode combines the advantages of the 3D electrode architecture and an advanced C60 coating/passivation concept leading to an improved electrochemical performance, due to an increased active surface area, a decreased charge transfer resistance, a prevented Co dissolution into the electrolyte and a suppressed side reaction and electrolyte decomposition. This work provides a novel solution for other cathode materials having similar concerns in high potential regimes for application in lithium-ion microbatteries.

  15. On Silicides in High Temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    C. Ramachandra

    1986-04-01

    Full Text Available High temperature titanium alloys like IMI 685 contain small amounts of silicon (~ 0.25 wt. per cent to improve creep resistance. Different types of silicides, namely Ti5Si3 (TiZr5Si3(S1 and (TiZr6 Si3 (S2, have been observed to precipitate in various silicon-bearing titanium alloys depending upon their composition and heat treatment. The precipitation of silicides, their orientation relationship with the matrix in different alloys, and the beneficial influence of thermo-mechanical treatment on the distribution of silicides have been pointed out. The effect of silicides on mechanical properties and fracture of the commercial alloy IMI 685 is also indicated.

  16. Turbine vane with high temperature capable skins

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Jay A [Oviedo, FL

    2012-07-10

    A turbine vane assembly includes an airfoil extending between an inner shroud and an outer shroud. The airfoil can include a substructure having an outer peripheral surface. At least a portion of the outer peripheral surface is covered by an external skin. The external skin can be made of a high temperature capable material, such as oxide dispersion strengthened alloys, intermetallic alloys, ceramic matrix composites or refractory alloys. The external skin can be formed, and the airfoil can be subsequently bi-cast around or onto the skin. The skin and the substructure can be attached by a plurality of attachment members extending between the skin and the substructure. The skin can be spaced from the outer peripheral surface of the substructure such that a cavity is formed therebetween. Coolant can be supplied to the cavity. Skins can also be applied to the gas path faces of the inner and outer shrouds.

  17. Electrode Kinetics in High Temperature Fuel Cells

    DEFF Research Database (Denmark)

    Bay, Lasse

    1998-01-01

    The O_2 reduction on Pt electrode with an yttria stabilized zirconia (YSZ) electrolyte is examined with potential step, voltammetry and impedance measurements. Inductive hysteresis are observed in all cases, indicating an activation-deactivation process for the electrode reaction. The same is found...... when the electrolyte is Gd doped ceria. The activation is generated by current passage. The time constant for the hysteresis is large considering the high operating temperatures, 800- 1000^oC. For the activation process potential steps give two time constants 10^2s and 10^3s for an anodic current, 10...... treated by modelling. The phenomenological model proposed can explain the principal behaviour of the inductive hysteresis. The activation process has first order dependence of the current density and the deactivation first order with respect to the activation.AFM pictures of the electrode...

  18. High temperature superconductivity space experiment (HTSSE)

    Science.gov (United States)

    Ritter, J. C.; Nisenoff, M.; Price, G.; Wolf, S. A.

    1991-01-01

    An experiment dealing with high-temperature superconducting devices and components in space is discussed. A variety of devices (primarily passive microwave and millimeter-wave components) has been procured and will be integrated with a cryogenic refrigerating and data acquisition system to form the space package, which will be launched in late 1992. This space experiment is expected to demonstrate that this technology is sufficiently robust to survive the space environment and that the technology has the potential to improve the operation of space systems significantly. The devices for the initial launch have been evaluated electrically, thermally, and mechanically, and will be integrated into the final space package early in 1991. The performance of the devices is summarized, and some potential applications of this technology in space systems are outlined.

  19. Chemical stability of high-temperature superconductors

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    A review of the available studies on the chemical stability of the high temperature superconductors (HTS) in various environments was made. The La(1.8)Ba(0.2)CuO4 HTS is unstable in the presence of H2O, CO2, and CO. The YBa2Cu3O(7-x) superconductor is highly susceptible to degradation in different environments, especially water. The La(2-x)Ba(x)CuO4 and Bi-Sr-Ca-Cu-O HTS are relatively less reactive than the YBa2Cu3O(7-x). Processing of YBa2Cu3O(7-x) HTS in purified oxygen, rather than in air, using high purity noncarbon containing starting materials is recommended. Exposure of this HTS to the ambient atmosphere should also be avoided at all stages during processing and storage. Devices and components made out of these oxide superconductors would have to be protected with an impermeable coating of a polymer, glass, or metal to avoid deterioration during use.

  20. HIGH TEMPERATURE OXIDATION PERFORMANCE OF ALUMINIDE COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Pint, B.A.; Zhang, Y.; Haynes, J.A.; Wright, I.G.

    2003-04-22

    In order to determine the potential benefits and limitations of aluminide coatings, coatings made by chemical vapor deposition (CVD) on Fe- and Ni-base alloy substrates are being evaluated in various high-temperature environments. Testing of coatings on representative ferritic (Fe-9Cr-1Mo) and austenitic (type 304L stainless steel) alloys has found that high frequency thermal cycling (1h cycle time) can significantly degrade the coating. Based on comparison with similar specimens with no thermal cycling or a longer cycle time (100h), this degradation was not due to Al loss from the coating but most likely because of the thermal expansion mismatch between the coating and the substrate. Several coated Ni-base alloys were tested in a high pressure (20atm) steam-CO2 environment for the ZEST (zero-emission steam turbine) program. Coated specimens showed less mass loss than the uncoated specimens after 1000h at 900 C and preliminary characterization examined the post-test coating structure and extent of attack.

  1. Assessment of high-temperature battery systems

    Energy Technology Data Exchange (ETDEWEB)

    Sen, R K

    1989-02-01

    Three classes of high-temperature batteries are being developed internationally with transportation and stationary energy storage applications in mind: sodium/sulfur, lithium/metal sulfide, and sodium/metal chloride. Most attention is being given to the sodium/sulfur system. The Office of Energy Storage and Distribution (OESD) and the Office of Transportation Systems (OTS) of the US Department of Energy (DOE) are actively supporting the development of this battery system. It is anticipated that pilot-scale production facilities for sodium/sulfur batteries will be in operation in the next couple of years. The lithium/metal sulfide and the sodium/metal chloride systems are not receiving the same level of attention as the sodium/sulfur battery. Both of these systems are in an earlier stage of development than sodium/sulfur. OTS and OESD are supporting work on the lithium/iron sulfide battery in collaboration with the Electric Power Research Institute (EPRI); the work is being carried out at Argonne National Laboratory (ANL). The sodium/metal chloride battery, the newest member of the group, is being developed by a Consortium of South African and British companies. Very little DOE funds are presently allocated for research on this battery. The purpose of this assessment is to evaluate the present status of the three technologies and to identify for each technology a prioritized list of R and D issues. Finally, the assessment includes recommendations to DOE for a proposed high-temperature battery research and development program. 18 figs., 21 tabs.

  2. Dynamic Model of High Temperature PEM Fuel Cell Stack Temperature

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2007-01-01

    cathode air cooled 30 cell HTPEM fuel cell stack developed at the Institute of Energy Technology at Aalborg University. This fuel cell stack uses PEMEAS Celtec P-1000 membranes, runs on pure hydrogen in a dead end anode configuration with a purge valve. The cooling of the stack is managed by running...... conduction through stack insulation, cathode air convection and heating of the inlet gasses in manifold. Various measurements are presented to validate the model predictions of the stack temperatures....

  3. Plasma nanotextured polymeric lab-on-a-chip for highly efficient bacteria capture and lysis.

    Science.gov (United States)

    Tsougeni, K; Papadakis, G; Gianneli, M; Grammoustianou, A; Constantoudis, V; Dupuy, B; Petrou, P S; Kakabakos, S E; Tserepi, A; Gizeli, E; Gogolides, E

    2016-01-07

    We describe the design, fabrication, and successful demonstration of a sample preparation module comprising bacteria cell capture and thermal lysis on-chip with potential applications in food sample pathogen analysis. Plasma nanotexturing of the polymeric substrate allows increase of the surface area of the chip and the antibody binding capacity. Three different anti-Salmonella antibodies were directly and covalently linked to plasma treated chips without any additional linker chemistry or other treatment. Then, the Ab-modified chips were tested for their capacity to bind bacteria in the concentration range of 10(2)-10(8) cells per mL; the module exhibited 100% efficiency in Salmonella enterica serovar Typhimurium bacteria capture for cell suspensions below 10(5) cells per mL (10(4) cells injected with a 100 μL sample volume) and efficiency higher than 50% for 10(7) cells per mL. Moreover, thermal lysis achieved on-chip from as low as 10 captured cells was demonstrated and shown to compare well with off-chip lysis. Excellent selectivity (over 1 : 300) was obtained in a sample containing, in addition to S. Typhimurium and E. coli bacteria.

  4. Molecular Dynamics Simulations of Liquid Phosphorus at High Temperature and Pressure

    Institute of Scientific and Technical Information of China (English)

    WU Yan-Ning; ZHAO Gang; LIU Chang-Song; ZHU Zhen-Gang

    2008-01-01

    By performing ab initio molecular dynamics simulations, we have investigated the mierostructure, dynam-ical and electronic properties of liquid phosphorus (P) under high temperature and pressure. In our simulations, the calculated coordination number (CN) changes discontinuously with density, and seems to increase rapidly after liquid P is compressed to 2.5 g/cm3. Under compression, liquid P shows the first-order liquid-liquid phase transition from the molecular liquid composed of the tetrahedral P4 molecules to complex polymeric form with three-dimensional network structure, accompanied by the nonmetal to metal transition of the electronic structure. The order parameters Q6 and Q4 are sensitive to the microstructural change of liquid P. By calculating diffusion coefficients, we show the dynamical anomaly of liquid P by compression. At lower temperatures, a maximum exists at the diffusion coefficients as a function of density; at higher temperatures, the anomalous behavior is weakened. The excess entropy shows the same phenom-ena as the diffusion coefficients. By analysis of the angle distribution functions and angular limited triplet correlation functions, we can clearly find that the Peierls distortion in polymeric form of liquid P is reduced by further compression.

  5. HIGH TEMPERATURE HIGH PRESSURE THERMODYNAMIC MEASUREMENTS FOR COAL MODEL COMPOUNDS

    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi

    2000-05-01

    The flow VLE apparatus designed and built for a previous project was upgraded and recalibrated for data measurements for this project. The modifications include better and more accurate sampling technique, addition of a digital recorder to monitor temperature and pressure inside the VLE cell, and a new technique for remote sensing of the liquid level in the cell. VLE data measurements for three binary systems, tetralin-quinoline, benzene--ethylbenzene and ethylbenzene--quinoline, have been completed. The temperature ranges of data measurements were 325 C to 370 C for the first system, 180 C to 300 C for the second system, and 225 C to 380 C for the third system. The smoothed data were found to be fairly well behaved when subjected to thermodynamic consistency tests. SETARAM C-80 calorimeter was used for incremental enthalpy and heat capacity measurements for benzene--ethylbenzene binary liquid mixtures. Data were measured from 30 C to 285 C for liquid mixtures covering the entire composition range. An apparatus has been designed for simultaneous measurement of excess volume and incremental enthalpy of liquid mixtures at temperatures from 30 C to 300 C. The apparatus has been tested and is ready for data measurements. A flow apparatus for measurement of heat of mixing of liquid mixtures at high temperatures has also been designed, and is currently being tested and calibrated.

  6. Mechanical behavior of high strength ceramic fibers at high temperatures

    Science.gov (United States)

    Tressler, R. E.; Pysher, D. J.

    1991-01-01

    The mechanical behavior of commercially available and developmental ceramic fibers, both oxide and nonoxide, has been experimentally studied at expected use temperatures. In addition, these properties have been compared to results from the literature. Tensile strengths were measured for three SiC-based and three oxide ceramic fibers for temperatures from 25 C to 1400 C. The SiC-based fibers were stronger but less stiff than the oxide fibers at room temperature and retained more of both strength and stiffness to high temperatures. Extensive creep and creep-rupture experiments have been performed on those fibers from this group which had the best strengths above 1200 C in both single filament tests and tests of fiber bundles. The creep rates for the oxides are on the order of two orders of magnitude faster than the polymer derived nonoxide fibers. The most creep resistant filaments available are single crystal c-axis sapphire filaments. Large diameter CVD fabricated SiC fibers are the most creep and rupture resistant nonoxide polycrystalline fibers tested to date.

  7. High Temperature Integrated Thermoelectric Ststem and Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mike S. H. Chu

    2011-06-06

    The final goal of this project is to produce, by the end of Phase II, an all ceramic high temperature thermoelectric module. Such a module design integrates oxide ceramic n-type, oxide ceramic p-type materials as thermoelectric legs and oxide ceramic conductive material as metalizing connection between n-type and p-type legs. The benefits of this all ceramic module are that it can function at higher temperatures (> 700 C), it is mechanically and functionally more reliable and it can be scaled up to production at lower cost. With this all ceramic module, millions of dollars in savings or in new opportunities recovering waste heat from high temperature processes could be made available. A very attractive application will be to convert exhaust heat from a vehicle to reusable electric energy by a thermoelectric generator (TEG). Phase I activities were focused on evaluating potential n-type and p-type oxide compositions as the thermoelectric legs. More than 40 oxide ceramic powder compositions were made and studied in the laboratory. The compositions were divided into 6 groups representing different material systems. Basic ceramic properties and thermoelectric properties of discs sintered from these powders were measured. Powders with different particles sizes were made to evaluate the effects of particle size reduction on thermoelectric properties. Several powders were submitted to a leading thermoelectric company for complete thermoelectric evaluation. Initial evaluation showed that when samples were sintered by conventional method, they had reasonable values of Seebeck coefficient but very low values of electrical conductivity. Therefore, their power factors (PF) and figure of merits (ZT) were too low to be useful for high temperature thermoelectric applications. An unconventional sintering method, Spark Plasma Sintering (SPS) was determined to produce better thermoelectric properties. Particle size reduction of powders also was found to have some positive benefits

  8. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Cleemann, Lars Nilausen; Steenberg, T.;

    2014-01-01

    High temperature operation of proton exchange membrane fuel cells under ambient pressure has been achieved by using phosphoric acid doped polybenzimidazole (PBI) membranes. To optimize the membrane and fuel cells, high performance polymers were synthesized of molecular weights from 30 to 94 k...... showed enhanced chemical stability towards radical attacks under the Fenton test, reduced volume swelling upon the acid doping and improved mechanical strength at acid doping levels of as high as about 11 mol H3PO4 per molar repeat polymer unit. The PBI‐78kDa/10.8PA membrane, for example, exhibited...... tensile strength of 30.3 MPa at room temperature or 7.3 MPa at 130 °C and a proton conductivity of 0.14 S cm–1 at 160 °C. Fuel cell tests with H2 and air at 160 °C showed high open circuit voltage, power density and a low degradation rate of 1.5 μV h–1 at a constant load of 300 mA cm–2....

  9. Crystal structures at high pressures and temperatures

    Science.gov (United States)

    Caldwell, Wendel Alexander

    2000-10-01

    The diamond anvil cell (DAC) is a unique instrument that can generate pressures equivalent to those inside planetary interiors (pressures on the order of 1 million atmospheres) under sustained conditions. When combined with a bright source of collimated x-rays, the DAC can be used to probe the structure of materials in-situ at ultra-high pressures. An understanding of the high-pressure structure of materials is important in determining what types of processes may take place in the Earth at great depths. Motivated by previous studies showing that xenon becomes metallic at pressures above ˜1 megabar (100 GPa), we examined the stable structures and reactivity of xenon at pressures approaching that of the core-mantle boundary in the Earth. Our findings indicate the transformation of xenon from face-centered cubic (fcc) to hexagonal close-packed (hcp) structures is kinetically hindered at room temperature, with the equilibrium fcc--hcp phase boundary at 21 (+/-3) gigapascals, a pressure lower than was previously thought. Additionally, we find no tendency on the part of xenon to form a metal alloy with iron or platinum to at least 100 to 150 gigapascals, making it unlikely that the Earth's core serves as a reservoir for primordial xenon. Measurements of the compressibility of natural (Mg.75,Fe .25)2SiO4 gamma-spinel at pressures of the Earth's transition zone yield a pressure derivative of the bulk modulus K0 ' = 6.3 (+/-0.3). As gamma-spinel is considered to be a dominant mineral phase of the transition-zone of the Earth's mantle (400--670 km depth), the relatively high value of K0' for gamma-spinel may help explain the rapid increase with depth of seismic velocities through the transition zone. The thermodynamics, mechanisms and kinetics of pressure-induced amorphization are not well understood. We report here new studies indicating little or no entropy difference between the crystalline and glassy states of Ca(OH) 2 (portlandite). Additional work on the pressure

  10. High temperature superconductors at optimal doping

    Directory of Open Access Journals (Sweden)

    W. E. Pickett

    2006-09-01

    Full Text Available   Intensive study of the high temperature superconductors has been ongoing for two decades. A great deal of this effort has been devoted to the underdoped regime, where the new and difficult physics of the doped Mott insulator has met extra complications including bilayer coupling/splitting, shadow bands, and hot spots. While these complications continue to unfold, in this short overview the focus is moved to the region of actual high-Tc, that of optimal doping. The focus here also is not on the superconducting state itself, but primarily on the characteristics of the normal state from which the superconducting instability arises, and even these can be given only a broad-brush description. A reminder is given of two issues,(i why the “optimal Tc” varies,for n-layered systems it increases for n up to 3, then decreases for a given n, Tc increases according to the ‘basis’ atom in the order Bi, Tl, Hg (ii how does pressure, or a particular uniaxial strain, increase Tc when the zero-strain system is already optimally doped?

  11. High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Biffi, C. A.; Tuissi, A.

    2014-10-01

    In this paper, an experimental study of laser micro-processing on a Cu-Zr-based shape memory alloy (SMA), which is suitable for high-temperature (HT) applications, is discussed. A first evaluation of the interaction between a laser beam and Zr50Cu28Ni7Co15 HT SMA is highlighted. Single laser pulses at various levels of power and pulse duration were applied to evaluate their effect on the sample surfaces. Blind and through microholes were produced with sizes on the order of a few hundreds of microns; the results were characterized from the morphological viewpoint using a scanning electron microscope. The high beam quality allows the holes to be created with good circularity and little melted material around the hole periphery. An analysis of the chemical composition was performed using energy dispersive spectroscopy, revealing that compositional changes were limited, while important oxidation occurred on the hole surfaces. Additionally, laser micro-cutting tests were also proposed to evaluate the cut edge morphology and dimensions. The main result of this paper concerned the good behavior of the material upon interaction with the laser beam, which suggests that microfeatures can be successfully produced in this alloy.

  12. High temperature superconductors in electromagnetic applications

    CERN Document Server

    Richens, P E

    2000-01-01

    powder-in-tube and dip-coated, have been made using a novel single loop tensometer that enables the insertion of a reasonably long length of conductor into the bore of a high-field magnet. The design, construction, and characterization of a High Temperature Superconducting (HTS) magnet is described. The design stage has involved the development of computer software for the calculation of the critical current of a solenoid wound from anisotropic HTS conductor. This calculation can be performed for a variety of problems including those involving magnetic materials such as iron by the incorporation of finite element electromagnetic analysis software. This has enabled the optimization of the magnet's performance. The HTS magnet is wound from 190 m of silver-matrix Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub 1 sub 0 powder-in-tube tape conductor supplied by Intermagnetics General Corporation. The dimensions are 70 mm bore and 70 mm length, and it consists of 728 turns. Iron end-plates were utilized in order to reduc...

  13. Assessment of microelectronics packaging for high temperature, high reliability applications

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, F.

    1997-04-01

    This report details characterization and development activities in electronic packaging for high temperature applications. This project was conducted through a Department of Energy sponsored Cooperative Research and Development Agreement between Sandia National Laboratories and General Motors. Even though the target application of this collaborative effort is an automotive electronic throttle control system which would be located in the engine compartment, results of this work are directly applicable to Sandia`s national security mission. The component count associated with the throttle control dictates the use of high density packaging not offered by conventional surface mount. An enabling packaging technology was selected and thermal models defined which characterized the thermal and mechanical response of the throttle control module. These models were used to optimize thick film multichip module design, characterize the thermal signatures of the electronic components inside the module, and to determine the temperature field and resulting thermal stresses under conditions that may be encountered during the operational life of the throttle control module. Because the need to use unpackaged devices limits the level of testing that can be performed either at the wafer level or as individual dice, an approach to assure a high level of reliability of the unpackaged components was formulated. Component assembly and interconnect technologies were also evaluated and characterized for high temperature applications. Electrical, mechanical and chemical characterizations of enabling die and component attach technologies were performed. Additionally, studies were conducted to assess the performance and reliability of gold and aluminum wire bonding to thick film conductor inks. Kinetic models were developed and validated to estimate wire bond reliability.

  14. The ultimate state of polymeric materials and laminated and fibrous composites under asymmetric high-cycle loading

    Science.gov (United States)

    Golub, V. P.; Pogrebniak, A. D.; Kochetkova, E. S.

    2008-01-01

    The prediction of the high-cycle fatigue strength of polymeric and composite materials in asymmetric loading is considered. The problem is solved on the basis of a nonlinear model of ultimate state allowing us to describe all typical forms of the diagrams of ultimate stresses. The material constants of the model are determined from the results of fatigue tests in symmetric reversed cycling, in a single fatigue test with the minimum stress equal to zero, and in a short-term strength test. The fatigue strength characteristics of some polymers, glass-fiber laminates, glass-fiber-reinforced plastics, organic-fiber-reinforced plastics, and wood laminates in asymmetric tension-compression, bending, and torsion have been calculated and approved experimentally.

  15. In Site Analysis of a High Temperature Cure Reaction in Real Time Using Modulated Fiber-Optic FT-Raman Spectroscopy

    Science.gov (United States)

    Cooper, John; Aust, Jeffrey F.; Wise, Kent L.; Jensen, Brian J.

    1999-01-01

    The vibrational spectrum of a high temperature (330 C) polymerization reaction was successfully monitored in real time using a modulated fiber-optic FT-Raman spectrometer. A phenylethynyl terminated monomer was cured, and spectral evidence for two different reaction products was acquired. The products are a conjugated polyene chain and a cyclized trimer. This is the first report describing the use of FT-Raman spectroscopy to monitor a high temperature (greater than 250 C) reaction in real time.

  16. Geochemistry of Aluminum in High Temperature Brines

    Energy Technology Data Exchange (ETDEWEB)

    Benezeth, P.; Palmer, D.A.; Wesolowski, D.J.

    1999-05-18

    The objective ofthis research is to provide quantitative data on the equilibrium and thermodynamic properties of aluminum minerals required to model changes in permeability and brine chemistry associated with fluid/rock interactions in the recharge, reservoir, and discharge zones of active geothermal systems. This requires a precise knowledge of the thermodynamics and speciation of aluminum in aqueous brines, spanning the temperature and fluid composition rangesencountered in active systems. The empirical and semi-empirical treatments of the solubility/hydrolysis experimental results on single aluminum mineral phases form the basis for the ultimate investigation of the behavior of complex aluminosilicate minerals. The principal objective in FY 1998 was to complete the solubility measurements on boehmite (AIOOH) inNaC1 media( 1 .O and 5.0 molal ionic strength, IOO-250°C). However, additional measurements were also made on boehmite solubility in pure NaOH solutions in order to bolster the database for fitting in-house isopiestic data on this system. Preliminary kinetic Measurements of the dissolution/precipitation of boehmite was also carried out, although these were also not planned in the earlier objective. The 1999 objectives are to incorporate these treatments into existing codes used by the geothermal industry to predict the chemistry ofthe reservoirs; these calculations will be tested for reliability against our laboratory results and field observations. Moreover, based on the success of the experimental methods developed in this program, we intend to use our unique high temperature pH easurement capabilities to make kinetic and equilibrium studies of pH-dependent aluminosilicate transformation reactions and other pH-dependent heterogeneous reactions.

  17. Raman Laser Polymerization of C60 Nanowhiskers

    Directory of Open Access Journals (Sweden)

    Ryoei Kato

    2012-01-01

    Full Text Available Photopolymerization of C60 nanowhiskers (C60NWs was investigated by using a Raman spectrometer in air at room temperature, since the polymerized C60NWs are expected to exhibit a high mechanical strength and a thermal stability. Short C60NWs with a mean length of 4.4 μm were synthesized by LLIP method (liquid-liquid interfacial precipitation method. The Ag(2 peak of C60NWs shifted to the lower wavenumbers with increasing the laser beam energy dose, and an energy dose more than about 1520 J/mm2 was found necessary to obtain the photopolymerized C60NWs. However, excessive energy doses at high-power densities increased the sample temperature and lead to the thermal decomposition of polymerized C60 molecules.

  18. Elaboration of highly hydrophobic polymeric surface — a potential strategy to reduce the adhesion of pathogenic bacteria?

    Energy Technology Data Exchange (ETDEWEB)

    Poncin-Epaillard, F., E-mail: fabienne.poncin-epaillard@univ-lemans.fr [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Herry, J.M. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France); Marmey, P.; Legeay, G. [CTTM, 20 rue Thalès de Milet 72000 Le Mans (France); Debarnot, D. [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Bellon-Fontaine, M.N. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France)

    2013-04-01

    Different polymeric surfaces have been modified in order to reach a high hydrophobic character, indeed the superhydrophobicity property. For this purpose, polypropylene and polystyrene have been treated by RF or μwaves CF{sub 4} plasma with different volumes, the results were compared according to the density of injected power. The effect of pretreatment such as mechanical abrasion or plasma activation was also studied. The modified surfaces were shown as hydrophobic, or even superhydrophobic depending of defects density. They were characterized by measurement of wettability and roughness at different scales, i.e. macroscopic, mesoscopic and atomic. It has been shown that a homogeneous surface at the macroscopic scale could be heterogeneous at lower mesoscopic scale. This was associated with the crystallinity of the material. The bioadhesion tests were performed with Gram positive and negative pathogenic strains: Listeria monocytogenes, Pseudomonas aeruginosa and Hafnia alvei. They have demonstrated an antibacterial efficiency of very hydrophobic and amorphous PS treated for all strains tested and a strain-dependent efficiency with modified PP surface being very heterogeneous at the mesoscopic scale. Thus, these biological results pointed out not only the respective role of the surface chemistry and topography in bacterial adhesion, but also the dependence on the peaks and valley distribution at bacteria dimension scale. Highlights: ► Simple, eco-friendly modification of polymers leading to highly hydrophobic property ► Plasma treatment inducing surface fluorination and roughness ► Study of non-adhesion of different types of bacteria onto such polymeric surfaces ► Dependence of their non-adhesion on surface topography whatever their characteristics.

  19. High Temperature Oxidation and Corrosion Properties of High Entropy Superalloys

    Directory of Open Access Journals (Sweden)

    Te-Kang Tsao

    2016-02-01

    Full Text Available The present work investigates the high temperature oxidation and corrosion behaviour of high entropy superalloys (HESA. A high content of various solutes in HESA leads to formation of complex oxides, however the Cr and Al activities of HESA are sufficient to promote protective chromia or alumina formation on the surface. By comparing the oxidation and corrosion resistances of a Ni-based superalloy—CM247LC, Al2O3-forming HESA can possess comparable oxidation resistance at 1100 °C, and Cr2O3-forming HESA can exhibit superior resistance against hot corrosion at 900 °C. This work has demonstrated the potential of HESA to maintain surface stability in oxidizing and corrosive environments.

  20. Organometallic Polymeric Conductors

    Science.gov (United States)

    Youngs, Wiley J.

    1997-01-01

    For aerospace applications, the use of polymers can result in tremendous weight savings over metals. Suitable polymeric materials for some applications like EMI shielding, spacecraft grounding, and charge dissipation must combine high electrical conductivity with long-term environmental stability, good processability, and good mechanical properties. Recently, other investigators have reported hybrid films made from an electrically conductive polymer combined with insulating polymers. In all of these instances, the films were prepared by infiltrating an insulating polymer with a precursor for a conductive polymer (either polypyrrole or polythiophene), and oxidatively polymerizing the precursor in situ. The resulting composite films have good electrical conductivity, while overcoming the brittleness inherent in most conductive polymers. Many aerospace applications require a combination of properties. Thus, hybrid films made from polyimides or other engineering resins are of primary interest, but only if conductivities on the same order as those obtained with a polystyrene base could be obtained. Hence, a series of experiments was performed to optimize the conductivity of polyimide-based composite films. The polyimide base chosen for this study was Kapton. 3-MethylThiophene (3MT) was used for the conductive phase. Three processing variables were identified for producing these composite films, namely time, temperature, and oxidant concentration for the in situ oxidation. Statistically designed experiments were used to examine the effects of these variables and synergistic/interactive effects among variables on the electrical conductivity and mechanical strength of the films. Multiple linear regression analysis of the tensile data revealed that temperature and time have the greatest effect on maximum stress. The response surface of maximum stress vs. temperature and time (for oxidant concentration at 1.2 M) is shown. Conductivity of the composite films was measured for

  1. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

    The current thesis studies experimentally the effect of high external pressure on high-T{sub c} superconductors. The structure and lattice dynamics of several members of the high-T{sub c} cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa{sub 2}Cu{sub 3}O{sub 6.55} samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa{sub 2}Cu{sub 4}O{sub 8}. A clear renormalization of some of the Raman phonons is seen below T{sub c} as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B{sub 1g}-like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa{sub 2}Cu{sub 3}O{sub 6+x}. At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group

  2. Rheological assessment of nanofluids at high pressure high temperature

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza

    2013-11-01

    High pressure high temperature (HPHT) fluids are commonly encountered in industry, for example in cooling and/or lubrications applications. Nanofluids, engineered suspensions of nano-sized particles dispersed in a base fluid, have shown prospective as industrial cooling fluids due to their enhanced rheological and heat transfer properties. Nanofluids can be potentially utilized in oil industry for drilling fluids and for high pressure water jet cooling/lubrication in machining. In present work rheological characteristics of oil based nanofluids are investigated at HPHT condition. Nanofluids used in this study are prepared by dispersing commercially available SiO2 nanoparticles (~20 nm) in a mineral oil. The basefluid and nanofluids with two concentrations, namely 1%, and 2%, by volume, are considered in this investigation. The rheological characteristics of base fluid and the nanofluids are measured using an industrial HPHT viscometer. Viscosity values of the nanofluids are measured at pressures of 100 kPa to 42 MPa and temperatures ranging from 25°C to 140°C. The viscosity values of both nanofluids as well as basefluid are observed to have increased with the increase in pressure. Funded by Qatar National Research Fund (NPRP 08-574-2-239).

  3. Laser Brazing of High Temperature Braze Alloy

    Science.gov (United States)

    Gao, Y. P.; Seaman, R. F.; McQuillan, T. J.; Martiens, R. F.

    2000-01-01

    The Space Shuttle Main Engine (SSME) consists of 1080 conical tubes, which are furnace brazed themselves, manifolds, and surrounding structural jacket making almost four miles of braze joints. Subsequent furnace braze cycles are performed due to localized braze voids between the coolant tubes. SSME nozzle experiences extremely high heat flux (180 mW/sq m) during hot fire. Braze voids between coolant tubes may result in hot combustion gas escape causing jacket bulges. The nozzle can be disqualified for flight or result in mission failure if the braze voids exceed the limits. Localized braze processes were considered to eliminate braze voids, however, damage to the parent materials often prohibited use of such process. Being the only manned flight reusable rocket engine, it has stringent requirement on the braze process. Poor braze quality or damage to the parent materials limits the nozzle service life. The objective of this study was to develop a laser brazing process to provide quality, localized braze joints without adverse affect on the parent materials. Gold (Au-Cu-Ni-Pd-Mn) based high temperature braze alloys were used in both powder and wire form. Thin section iron base superalloy A286 tube was used as substrate materials. Different Laser Systems including CO2 (10.6 micrometers, 1kW), ND:YAG (1.06 micrometers, 4kW). and direct diode laser (808nm. 150W) were investigated for brazing process. The laser process variables including wavelength. laser power, travel speed and angle of inclination were optimized according to bead geometry and braze alloy wetting at minimum heat input level, The properties of laser brazing were compared to that of furnace brazing. Microhardness profiles were used for braze joint property comparison between laser and furnace brazing. The cooling rate of laser brazing was compared to furnace brazing based on secondary dendritic arm spacing, Both optical and Scanning Electron Microscope (SEM) were used to evaluate the microstructures of

  4. Analytic Models of High-Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Stygar, W.A.; Olson, R.E.; Spielman, R.B.; Leeper, R.J.

    2000-11-29

    A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P{sub s} = [A{sub s}+(1{minus}{alpha}{sub W})A{sub W}+A{sub H}]{sigma}T{sub R}{sup 4} + (4V{sigma}/c)(dT{sub R}{sup r}/dt) where P{sub S} is the total power radiated by the source, A{sub s} is the source area, A{sub W} is the area of the cavity wall excluding the source and holes in the wall, A{sub H} is the area of the holes, {sigma} is the Stefan-Boltzmann constant, T{sub R} is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo {alpha}{sub W} {triple_bond} (T{sub W}/T{sub R}){sup 4} where T{sub W} is the brightness temperature of area A{sub W}. The net power radiated by the source P{sub N} = P{sub S}-A{sub S}{sigma}T{sub R}{sup 4}, which suggests that for laser-driven hohlraums the conversion efficiency {eta}{sub CE} be defined as P{sub N}/P{sub LASER}. The characteristic time required to change T{sub R}{sup 4} in response to a change in P{sub N} is 4V/C[(l{minus}{alpha}{sub W})A{sub W}+A{sub H}]. Using this model, T{sub R}, {alpha}{sub W}, and {eta}{sub CE} can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, P{sub N} = {l_brace}(1{minus}{alpha}{sub W})A{sub W}+A{sub H}+[(1{minus}{alpha}{sub C})(A{sub S}+A{sub W}{alpha}{sub W})A{sub C}/A{sub T}]{r_brace}{sigma}T{sub RC}{sup 4} where {alpha}{sub C} is the capsule albedo, A{sub C} is the capsule area, A{sub T} {triple_bond} (A{sub S}+A{sub W}+A{sub H}), and T{sub RC} is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented.

  5. Solid Nitrogen at Extreme Conditions of High Pressure and Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, A; Gregoryanz, E

    2004-04-05

    We review the phase diagram of nitrogen in a wide pressure and temperature range. Recent optical and x-ray diffraction studies at pressures up to 300 GPa and temperatures in excess of 1000 K have provided a wealth of information on the transformation of molecular nitrogen to a nonmolecular (polymeric) semiconducting and two new molecular phases. These newly found phases have very large stability (metastability) range. Moreover, two new molecular phases have considerably different orientational order from the previously known phases. In the iota phase (unlike most of other known molecular phases), N{sub 2} molecules are orientationally equivalent. The nitrogen molecules in the theta phase might be associated into larger aggregates, which is in line with theoretical predictions on polyatomic nitrogen.

  6. NOVEL REFRACTORY MATERIALS FOR HIGH ALKALI, HIGH TEMPERATURE ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.

    2012-08-01

    A project was led by Oak Ridge National Laboratory (ORNL) in collaboration with a research team comprised of the academic institution Missouri University of Science and Technology (MS&T), and the industrial company MINTEQ International, Inc. (MINTEQ), along with representatives from the aluminum, chemical, glass, and forest products industries. The project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al 2O3, MgAl2O4, or other similar spinel structured or alumina-based unshaped refractory compositions (castables, gunnables, shotcretes, etc.) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques (in-situ phase formation, altered conversion temperatures, accelerated reactions, etc). This family of refractory compositions would then be tailored for use in high-temperature, high-alkaline industrial environments like those found in the aluminum, chemical, forest products, glass, and steel industries. Both practical refractory development experience and computer modeling techniques were used to aid in the design of this new family of materials. The newly developed materials were expected to offer alternative material choices for high-temperature, high-alkali environments that were capable of operating at higher temperatures (goal of increasing operating temperature by 100-200oC depending on process) or for longer periods of time (goal of twice the life span of current materials or next process determined service increment). This would lead to less process down time, greater energy efficiency for associated manufacturing processes (more heat kept in process), and materials that could be installed/repaired in a more efficient manner. The overall project goal was a 5% improvement in energy efficiency (brought about through a 20% improvement in thermal efficiency) resulting in a savings of 3.7 TBtu/yr (7.2 billion ft3 natural gas) by the year 2030. Additionally, new

  7. Measuring Specific Heats at High Temperatures

    Science.gov (United States)

    Vandersande, Jan W.; Zoltan, Andrew; Wood, Charles

    1987-01-01

    Flash apparatus for measuring thermal diffusivities at temperatures from 300 to 1,000 degrees C modified; measures specific heats of samples to accuracy of 4 to 5 percent. Specific heat and thermal diffusivity of sample measured. Xenon flash emits pulse of radiation, absorbed by sputtered graphite coating on sample. Sample temperature measured with thermocouple, and temperature rise due to pulse measured by InSb detector.

  8. High Temperature Electrical Insulation Materials for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's future space science missions cannot be realized without the state of the art high temperature insulation materials of which higher working temperature, high...

  9. Thermoelectric Powered High Temperature Wireless Sensing

    Science.gov (United States)

    Kucukkomurler, Ahmet

    This study describes use of a thermoelectric power converter to transform waste heat into electrical energy to power an RF receiver and transmitter, for use in harsh environment wireless temperature sensing and telemetry. The sensing and transmitting module employs a DS-1820 low power digital temperature sensor to perform temperature to voltage conversion, an ATX-34 RF transmitter, an ARX-34 RF receiver module, and a PIC16f84A microcontroller to synchronize data communication between them. The unit has been tested in a laboratory environment, and promising results have been obtained for an actual automotive wireless under hood temperature sensing and telemetry implementation.

  10. Critical Temperature Characteristics of Layered High-Temperature Superconductor Under Pressure

    Institute of Scientific and Technical Information of China (English)

    LIANG Fang-Ying

    2009-01-01

    We consider a Ginzburg-Landau modified model of layered high-temperature superconductor under pres-sure. We have theoretically studied the relation between the pressure and the temperature of layered high-temperature superconductor. If the pressure is not a constant, we have a relation of quadratic equation between the pressure and the temperature of layered high-temperature superconductor. In a special case, we find the critical temperature decreases with further increasing pressure. In another special case, the critical temperature increases with further increasing pressure.

  11. Processing Mechanisms, Structure and Morphology of High Temperature Polymeric Alloys. Part I.

    Science.gov (United States)

    1978-04-01

    as is and the particle size was reduced by cryogenic grinding using a Mikro -Pulverizer hammer mill. The grindin g pro - cedure used was to pre -cool...cases except for the modulus of the pure BBB at 475 ’C which falls slightly. Increasing the load leads to a decrease in pro - pertie s except for the

  12. Synthesis of optically clear polymeric materials for high temperature windows. [preparation of phenolphthalein polycarbonate resin

    Science.gov (United States)

    Pannell, C. E.; Magner, J. E.

    1973-01-01

    A polymer has been developed that has excellent potential for use as windows in spacecraft as well as conventional aircraft. This polymer, phenolphthalein polycarbonate, has outstanding thermal properties, e.g., in place of melting or burning, it produces an insulating charred foam that closes off transmission of radiant heat through the window. This fact, coupled with an oxygen index of 0.43 and a 177 C tensile strength of 58 mega Newtons/sq m, makes this polymer a prime candidate for further development. Pilot plant preparation in a 20 gallon Pfaudler kettle was accomplished and large test specimens were prepared for evaluations.

  13. High temperature superconductivity induced by incipient magnetism

    Science.gov (United States)

    Weger, M.; Pereg, Y.

    1990-10-01

    We consider the BCS gap equation, with an attractive interaction λ with an upper cutoff ω 0 and lower cutoff ω 1, and a repulsive interaction μ with cutoffΓ. We consider parameters such that a superconducting solution does not exist. We add a repulsive interaction ν eith cutoff ω1 ( ω1 < ω0), and show that this repulsive interaction (that we attribute to incipient magnetism) induces a superconducting state possessing a high transition temperature. In this state, the gap function Δ(ɛ) oscillates as function of ɛ, with a period of order ω 0. We also find solutions antisymmetric in energy [ Δ( ɛ) = - Δ(- ɛ) ], which turn out to be almost degenerate with the normal, symmetric ones. We discuss the physical implications of this model. Our model thus combines a low frequency repulsion due to antiferromagnetic interactions, with excitonic attraction at intermediate frequencies, and ordinary Coulomb repulsion above that. All frequency ranges, and coupling strengths, are comparable with the bandwidth.

  14. High temperature bacterial leaching: HIOX project

    Energy Technology Data Exchange (ETDEWEB)

    Morin, D.; D' Hugues, P.; Bonney, C. F.; Norris, P.; Shwab, W.; Sundkvist, J-E.; Bridges, P. [Bureau de Recherhes Geologiques et Minieres, Orleans (France)

    2001-07-01

    The HIOX project was designed to investigate the use of thermophilic bacterial cultures for the leaching of chalcopyrite (CuFeS{sub 2}, the natural source of copper). Beyond bacterial leaching, the study also encompassed the downstream processing steps in an effort to develop a new method for the recovery of copper in an economical and environmentally-friendly process. Using the HIOX process copper recovery was increased to better than 90 per cent within 5 days with a 12 per cent solids culture, although some potentially limiting factors such as foam generation, nutrient concentrations and mixing/aeration efficiency were also identified. The study resulted in the establishment of a mass balance based on a simplified flowsheet of the process. Techno-economic evaluation carried out at three sites indicated technical feasibility using relatively conventional equipment and capital and operating costs in ranges that suggest that bioleaching with high temperature bacteria is an attractive alternative for the treatment of chalcopyrite concentrate. 5 tabs.

  15. Turbulent Flow past High Temperature Surfaces

    Science.gov (United States)

    Mehmedagic, Igbal; Thangam, Siva; Carlucci, Pasquale; Buckley, Liam; Carlucci, Donald

    2014-11-01

    Flow over high-temperature surfaces subject to wall heating is analyzed with applications to projectile design. In this study, computations are performed using an anisotropic Reynolds-stress model to study flow past surfaces that are subject to radiative flux. The model utilizes a phenomenological treatment of the energy spectrum and diffusivities of momentum and heat to include the effects of wall heat transfer and radiative exchange. The radiative transport is modeled using Eddington approximation including the weighted effect of nongrayness of the fluid. The time-averaged equations of motion and energy are solved using the modeled form of transport equations for the turbulence kinetic energy and the scalar form of turbulence dissipation with an efficient finite-volume algorithm. The model is applied for available test cases to validate its predictive capabilities for capturing the effects of wall heat transfer. Computational results are compared with experimental data available in the literature. Applications involving the design of projectiles are summarized. Funded in part by U.S. Army, ARDEC.

  16. High-temperature archeointensity measurements from Mesopotamia

    Science.gov (United States)

    Gallet, Yves; Le Goff, Maxime

    2006-01-01

    We present new archeointensity results obtained from 127 potsherds and baked brick fragments dated from the last four millennia BC which were collected from different Syrian archeological excavations. High temperature magnetization measurements were carried out using a laboratory-built triaxial vibrating sample magnetometer (Triaxe), and ancient field intensity determinations were derived from the experimental procedure described by Le Goff and Gallet [Le Goff and Gallet. Earth Planet. Sci. Lett. 229 (2004) 31-43]. As some of the studied samples were previously analyzed using the classical Thellier and Thellier [Thellier and Thellier . Ann. Geophys. 15 (1959) 285-376] method revised by Coe [Coe. J. Geophys. Res. 72 (1967) 3247-3262], a comparison of the results is made from the two methods. The differences both at the fragment and site levels are mostly within ± 5%, which strengthens the validity of the experimental procedure developed for the Triaxe. The new data help to better constrain the geomagnetic field intensity variations in Mesopotamia during archeological times, with the probable occurrence of an archeomagnetic jerk around 2800-2600 BC.

  17. Electronic phase separation and high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kivelson, S.A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics; Emery, V.J. [Brookhaven National Lab., Upton, NY (United States)

    1994-01-11

    The authors review the extensive evidence from model calculations that neutral holes in an antiferromagnet separate into hole-rich and hole-poor phases. All known solvable limits of models of holes in a Heisenberg antiferromagnet exhibit this behavior. The authors show that when the phase separation is frustrated by the introduction of long-range Coulomb interactions, the typical consequence is either a modulated (charge density wave) state or a superconducting phase. The authors then review some of the strong experimental evidence supporting an electronically-driven phase separation of the holes in the cuprate superconductors and the related Ni oxides. Finally, the authors argue that frustrated phase separation in these materials can account for many of the anomalous normal state properties of the high temperature superconductors and provide the mechanism of superconductivity. In particular, it is shown that the T-linear resistivity of the normal state is a paraconductivity associated with a novel composite pairing, although the ordered superconducting state is more conventional.

  18. Spin injection into high temperature superconductor

    CERN Document Server

    Severac, C H L

    2000-01-01

    DELTA M versus pulse length was measured. It showed two regions: above 100 mu s DELTA M is the same for both magnetic and non-magnetic material and can be attributed to heating. Below 100 mu s, DELTA M is only significant for the CMR samples. This is attributed to the injection of highly spin polarised carriers that are believed to reduce the order parameter over the whole sample, and hence l sub C and the magnetic moment of the sample. As part of a search for colossal magneto-resistance (CMR) materials with Curie temperature below the superconducting transition of YBCO, we made an investigation of the magnetic and electrical characteristics of Chromium doped LCMO. We found that the conduction mechanism which depends on the orbital order via the double-exchange mechanism, is decoupled from the ferromagnetic behaviour, which is related to spin order. Work on the injection of dc-current from half metallic CMR material into YBa sub 2 Cu sub 3 O sub 7 sub - subdelta (YBCO) showed a shift and a compression in the ...

  19. Development of Strengthened Bundle High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lue, J.W.; Lubell, M.S. [Oak Ridge National Lab., TN (United States); Demko, J.A. [Oak Ridge Inst. for Science and Education, TN (United States); Tomsic, M. [Plastronic, Inc., Troy, OH (United States); Sinha, U. [Southwire Company, Carollton, GA (United States)

    1997-12-31

    In the process of developing high temperature superconducting (HTS) transmission cables, it was found that mechanical strength of the superconducting tape is the most crucial property that needs to be improved. It is also desirable to increase the current carrying capacity of the conductor so that fewer layers are needed to make the kilo-amp class cables required for electric utility usage. A process has been developed by encapsulating a stack of Bi-2223/Ag tapes with a silver or non-silver sheath to form a strengthened bundle superconductor. This process was applied to HTS tapes made by the Continuous Tube Forming and Filling (CTFF) technique pursued by Plastronic Inc. and HTS tapes obtained from other manufacturers. Conductors with a bundle of 2 to 6 HTS tapes have been made. The bundled conductor is greatly strengthened by the non-silver sheath. No superconductor degradation as compared to the sum of the original critical currents of the individual tapes was seen on the finished conductors.

  20. High-temperature Gas Reactor (HTGR)

    Science.gov (United States)

    Abedi, Sajad

    2011-05-01

    General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.