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Sample records for bearing oh nh

  1. Catalytic effect of a single water molecule on the OH + CH2NH reaction.

    Science.gov (United States)

    Akbar Ali, Mohamad; M, Balaganesh; Lin, K C

    2018-02-07

    In recent work, there has been considerable speculation about the atmospheric reaction of methylenimine (CH 2 NH), because this compound is highly reactive, soluble in water, and sticky, thus posing severe experimental challenges. In this work, we have revisited the kinetics of the OH + CH 2 NH reaction assisted by a single water molecule. The potential energy surfaces (PESs) for the water-assisted OH + CH 2 NH reaction were calculated using the CCSD(T)//BH&HLYP/aug-cc-pVTZ levels of theory. The rate coefficients for the bimolecular reaction pathways CH 2 NHH 2 O + OH and CH 2 NH + H 2 OHO were computed using canonical variational transition state theory (CVT) with small curvature tunneling correction. The reaction without water has four elementary reaction pathways, depending on how the hydroxyl radical approaches CH 2 NH. In all cases, the reaction begins with the formation of a single pre-reactive complex before producing abstraction and addition products. When water is added, the products of the reaction do not change, and the reaction becomes quite complex, yielding four different pre-reactive complexes and eight reaction pathways. The calculated rate coefficient for the OH + CH 2 NH (water-free) reaction at 300 K is 1.7 × 10 -11 cm 3 molecule -1 s -1 and for OH + CH 2 NH (water-assisted), it is 5.1 × 10 -14 cm 3 molecule -1 s -1 . This result is similar to the isoelectronic analogous reaction OH + CH 2 O (water-assisted). In general, the effective rate coefficients of the water-assisted reaction are 2∼3 orders of magnitude smaller than water-free. Our results show that the water-assisted OH + CH 2 NH reaction cannot accelerate the reaction because the dominated water-assisted process depends parametrically on water concentration. As a result, the overall reaction rate coefficients are smaller.

  2. Comparison of Three Isoelectronic Multiple-Well Reaction Systems: OH + CH2O, OH + CH2CH2, and OH + CH2NH.

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    Akbar Ali, Mohamad; Barker, John R

    2015-07-16

    Methylenimine (CH2NH) has been predicted to be a product of the atmospheric photo-oxidation of methylamine, but its atmospheric reactions have not been measured. In this paper, we report potential energy surfaces (PESs) and rate constants for OH + CH2NH and its isoelectronic analogues OH + CH2O and OH + CH2CH2, which are more fully understood. The PESs were computed using the BHandHLYP/aug-cc-pVTZ and CCSD(T)/aug-cc-pVTZ levels of theory. Canonical variational transition state theory and Rice-Ramsperger-Kassel-Marcus and master equation modeling were used to calculate temperature- and pressure-dependent rate constants, with particular emphasis on the OH + reactant entrance channels and the effects of prereactive complexes. The computed results are in reasonable agreement with experimental data where they can be compared and also with the results of previous theoretical calculations. The results show that to some extent OH radicals both add to the carbon center double bond in CH2NH and abstract methylene hydrogen atoms, as in the OH + CH2O and OH + CH2CH2 reactions, respectively, but the dominant pathway is abstraction of the hydrogen from N-H. The computed rate constants are suitable for both atmospheric and combustion modeling.

  3. NH(4)OH-KOH pulping mechanisms and kinetics of rice straw.

    Science.gov (United States)

    Huang, Guolin; Shi, Jeffrey X; Langrish, Tim A G

    2007-04-01

    The mechanisms and kinetics of NH(4)OH-KOH mixture pulping rice straw were studied. When aqueous ammonia was mixed with a small amount of caustic potash (ratio of 1:5), three distinct delignification phases were observed in the pulping process: a bulk delignification phase from the beginning of the cooking period to 100 degrees C, a supplementary delignification phase from 100 degrees C to 155 degrees C lasting a further 45 min, and a residual delignification phase until the end of the cooking period. There were two silica removal phases; the first phase was from the beginning of the cooking period to 100 degrees C and the second phase was from 100 degrees C to the end of the cooking period. The rate of delignification reaction was first order with respect to residual lignin and 0.3 order with respect to [OH(-)]. The silica removal was pseudo-first-order with respect to residual silica and 0.6 order with respect to [OH(-)]. The activation energies of the delignification and removal of silica reactions were 35.6 and 30.9 kJ/mol, respectively.

  4. Dynamic investigation of the diffusion absorption refrigeration system NH3-H2O-H2

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    Mohamed Izzedine Serge Adjibade

    2017-09-01

    Full Text Available This paper reports on a numerical and experimental study of a diffusion absorption refrigerator. The performance of the system is examined by computer simulation using MATLAB software and Engineering Equations Solver. A dynamic model is developed for each component of the system and solved numerically in order to predict the transient state of the diffusion absorption refrigeration. The experiment set included 0.04 m3 commercial absorption diffusion refrigerator working with the ammonia-water-hydrogen (NH3-H2O-H2 solution. The transient numerical results were validated with the experimental data. The investigations are focused on the dynamic profile of the temperature of each component. The results obtained agree with the experiment; the relative error between numerical and experimental models doesn’t exceed 15% for all temperatures of each component. The increase of the average ambient temperature from 23.04 °C to 32.56 °C causes an increase of the condensation temperature from 29.46 °C to 37.51 °C, and the best evaporation temperature obtained was 3 °C, with an ambient temperature of 23.04 °C. The results show that a minimum starting temperature of 152 °C and 63.8 W electric power are required to initiate the decrease of evaporation temperature.

  5. In situ attenuated total reflection infrared (ATR-IR) study of the adsorption of NO2-, NH2OH, and NH4+ on Pd/Al2O3 and Pt/Al2O3.

    NARCIS (Netherlands)

    Ebbesen, S.D.; Mojet, Barbara; Lefferts, Leonardus

    2008-01-01

    In relation to the heterogeneous hydrogenation of nitrite, adsorption of NO2-, NH4+, and NH2OH from the aqueous phase was examined on Pt/Al2O3, Pd/Al2O3, and Al2O3. None of the investigated inorganic nitrogen compounds adsorb on alumina at conditions presented in this study. NO2-(aq) and NH4+(aq) on

  6. Dynamics study of the OH + NH3 hydrogen abstraction reaction using QCT calculations based on an analytical potential energy surface.

    Science.gov (United States)

    Monge-Palacios, M; Corchado, J C; Espinosa-Garcia, J

    2013-06-07

    To understand the reactivity and mechanism of the OH + NH3 → H2O + NH2 gas-phase reaction, which evolves through wells in the entrance and exit channels, a detailed dynamics study was carried out using quasi-classical trajectory calculations. The calculations were performed on an analytical potential energy surface (PES) recently developed by our group, PES-2012 [Monge-Palacios et al. J. Chem. Phys. 138, 084305 (2013)]. Most of the available energy appeared as H2O product vibrational energy (54%), reproducing the only experimental evidence, while only the 21% of this energy appeared as NH2 co-product vibrational energy. Both products appeared with cold and broad rotational distributions. The excitation function (constant collision energy in the range 1.0-14.0 kcal mol(-1)) increases smoothly with energy, contrasting with the only theoretical information (reduced-dimensional quantum scattering calculations based on a simplified PES), which presented a peak at low collision energies, related to quantized states. Analysis of the individual reactive trajectories showed that different mechanisms operate depending on the collision energy. Thus, while at high energies (E(coll) ≥ 6 kcal mol(-1)) all trajectories are direct, at low energies about 20%-30% of trajectories are indirect, i.e., with the mediation of a trapping complex, mainly in the product well. Finally, the effect of the zero-point energy constraint on the dynamics properties was analyzed.

  7. Influence of the use of NaOH and NH{sub 4}OH the synthesis of iron oxide nanoparticles by coprecipitation; Influencia da utilizacao de NaOH e NH{sub 4}OH na sintese de nanoparticulas de oxido de ferro por coprecipitacao

    Energy Technology Data Exchange (ETDEWEB)

    Panta, P.C.; Zampiva, R.Y.S., E-mail: pr.priscila@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), RS (Brazil). Programa de Pos-Graduaco em Engenharia de Minas, Metalurgica e de Materiais; Campos, H.G.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (UFRGS), RS (Brazil), Escola de Engenharia

    2012-07-01

    Numerous chemical methods can be used to synthesize iron oxide nanoparticles, including, microemulsion, sol-gel, polyol among others. This work was used because of advantages such as coprecipitation simplicity and large scale production. The goal is to control the characteristics and stability of nanoparticles. Thus, it is a reaction in aqueous iron salts with a base (NaOH, NH{sub 4}OH, etc.) In which parameters such as quality and the molar ratio of base used were varied to control the morphology that the particles, and consequently varying the grain size. Factors such as reaction time and temperature, pH, influence on morphology, and magnetic. There were measures of X-ray diffraction and scanning electron microscopy to obtain the phases and average diameters. The results show that as the choice of base used and its molar concentration variation occurring in the sizes of the iron oxide nanoparticles. (author)

  8. Vibrational spectroscopic analysis of taranakite (K,NH4)Al3(PO4)3(OH)·9(H2O) from the Jenolan Caves, Australia.

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    Frost, Ray L; Xi, Yunfei; Palmer, Sara J; Pogson, Ross E

    2011-12-01

    Many phosphate containing minerals are found in the Jenolan Caves. Such minerals are formed by the reaction of bat guano and clays from the caves. Among these cave minerals is the mineral taranakite (K,NH(4))Al(3)(PO(4))(3)(OH)·9(H(2)O) which has been identified by X-ray diffraction. Jenolan Caves taranakite has been characterised by Raman spectroscopy. Raman and infrared bands are assigned to H(2)PO(4), OH and NH stretching vibrations. By using a combination of XRD and Raman spectroscopy, the existence of taranakite in the caves has been proven. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Clean production of corn stover pulp using KOH+NH4OH solution and its kinetic during delignification

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    Sun Yong

    2012-01-01

    Full Text Available The self-made KOH together with NH4OH pulping of corn stover was investigated. The combined alkaline system could effectively remove lignin during pulping. There are three stages of lignin removal during delginification. Approximately 90% of lignin could be removed after temperature reached 150ºC for over 30 minutes. The p-hydroxyl phenol groups in lignin could be completely removed during the delignification reaction. The tendency of the increase of the crystalline degree of cellulose is observed with increase of reaction temperature. The kinetics of delignification is found to be the first order with respect to the remained lignin and the 0.4 order with respect to the remained hydroxide concentration. The activation energy of delignification is 23 kJ/mol. The solution obtained from precipitation of lignin is rich in nitrogen, phosphorous, potassium elements and organic matters. Various techniques including FT-IR, GPC, DSC, were applied to characterize the acid precipitated lignin. The result shows that the lignin with the polydispersity of 1.4 still maintains the p-coumaryl, coniferyl, and sinapyl units in its matrix.

  10. COMPARATIVE PHARMACOKINETICS OF PAMAM-OH DENDRIMERS AND HPMA COPOLYMERS IN OVARIAN-TUMOR-BEARING MICE.

    Science.gov (United States)

    Sadekar, S; Linares, O; Noh, Gj; Hubbard, D; Ray, A; Janát-Amsbury, M; Peterson, C M; Facelli, J; Ghandehari, H

    2013-06-01

    The purpose of this study was to model data from a head to head comparison of the in vivo fate of hyper-branched PAMAM dendrimers with linear HPMA copolymers in order to understand the influence of molecular weight (MW), hydrodynamic size (Rh) and polymer architecture on biodistribution in tumor-bearing mice using compartmental pharmacokinetic analysis. Plasma concentration data was modeled by two-compartment analysis using Winnonlin® to obtain elimination clearance (E.CL) and plasma exposure (AUC plasma ). Renal clearance (CL R ) was calculated from urine data collected over 1 week. A plasma-tumor link model was fitted to experimental plasma and tumor data by varying the tumor extravasation (K 4 , K 6 ) and elimination (K 5 ) rate constants using multivariable constrained optimization solver in Matlab®. Tumor exposures (AUC tumor ) were computed from area under the tumor concentration time profile curve by the linear trapezoidal method. Along with MW and Rh, polymer architecture was critical in affecting the blood and tumor pharmacokinetics of the PAMAM-OH dendrimers and HPMA copolymers. Elimination clearance decreased more rapidly with increase in hydrodynamic size for PAMAM-OH dendrimers as compared to HPMA copolymers. HPMA copolymers were eliminated renally to a higher extent than PAMAM-OH dendrimers. These results are suggestive of a difference in extravasation of polymers of varying architecture through the glomerular basement membrane. While the linear HPMA copolymers can potentially reptate through a pore smaller in size than their hydrodynamic radii in a random coil conformation, PAMAM dendrimers have to deform in order to permeate across the pores. With increase in molecular weight or generation, the deforming capacity of PAMAM-OH dendrimers is known to decrease, making it harder for higher generation PAMAM-OH dendrimers to sieve through the glomerulus as compared to HPMA copolymers of comparable molecular weights. PAMAM-OH dendrimer had greater tumor

  11. Removal of Aluminum from the Dissolved Alumina Matrix by NH{sub 4}OH Precipitation and Chelate Ion Exchange Resin

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    Suh, Jung Ki; Kim, Chang Soo; Han, Myung Sub; Lee, Hwa Shim [Korea Research Institute of Standardsand Science, Daejeon (Korea, Republic of)

    2016-03-15

    Many studies have been devoted to the determination of trace elements in alumina matrices using high sensitivity techniques such as inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS). The dissolved alumina samples contain high concentrations of aluminum (Al) and sulfuric acid. High Al concentrations can cause high background emission from 190 to 250 nm and can increase the detection limit of ICP-OES. Furthermore, reactions between the Al matrix and quartz from the quartz torch used in high temperature plasmas can result in the formation of aluminosilicate (3Al{sub 2}O{sub 3}–2SiO{sub 2}), which reduce the torch lifetime. High concentration of Al matrix can also form a white deposit on the skimmer and the sampler cone, and block the orifice. These problems prevent the long-term use of ICP-MS seriously. NIST SRM 699 alumina was used as a test sample for the removal of the Al and the recovery of trace metals from matrix. First, about 1 g of NIST SRM 699 alumina standard was dissolved with 40 mL of 25% H{sub 2}SO{sub 4} for 65 h at 230 °C in PolytetraFluoroethylene (PTFE) vessel and diluted with deionized water to be about 100 g. For fast and simple separation of the two solid layers, 5 mL aliquots of 0.1 M NH4OH solution were added and the solutions were shaken gently; then, only the swollen resin layer was transferred to another tube. This transfer process was repeated several times.

  12. OH-point defects in quartz in B- and Li-bearing systems and their application to pegmatites

    Science.gov (United States)

    Baron, M. A.; Stalder, R.; Konzett, J.; Hauzenberger, C. A.

    2015-01-01

    OH incorporation in quartz in Al-, B- and Li-bearing systems (granitic systems containing tourmaline or spodumene) was studied experimentally in order to investigate the effect of pressure, temperature and chemical impurities on the generation of OH-defects. High-pressure experiments were carried out at pressures between 5 and 25 kbar and temperatures between 800 and 900 °C, and OH-contents in quartz were calculated from IR absorption spectra measured on oriented quartz crystals. IR absorption features were assigned to impurity substitutions, such as AlOH (3,420, 3,379 and 3,315 cm-1) and BOH (3,595 cm-1), LiOH (3,483 cm-1), and hydrogarnet substitution (4H)Si defects (3,583 cm-1). Results indicate a negative correlation of incorporated Al-specific OH-defect content versus pressure (630 ± 130 wt ppm H2O at 5 kbar to 102 ± 6 wt ppm H2O at 25 kbar), but no clear correlation of B-specific OH-defects with pressure. In runs initially containing spodumene, virtually OH-free quartzes were observed at pressures ≥10 kbar, where impurity cations compensate each other forming an anhydrous eucryptite-defect component. In contrast, at 5 kbar, both Li- ad Al-specific OH-defects are observed (corresponding to 470 ± 75 wt ppm H2O). Results from this study may therefore be used to monitor formation conditions of quartz in terms of pressure and trace metal saturation of the crystallizing petrological system. IR spectra obtained from natural quartz grains from a tourmaline-bearing pegmatite exhibit B- and Al-related OH-bands. The B-related OH-band is also exhibited in quartz from a tourmaline + spodumene-bearing pegmatite. Li- and Al-related OH-bands, however, are subordinate or not observed at all in the spodumene-bearing system, which suggests that OH-vibrations do not reflect absolute Li-contents in quartz due to efficient coupled substitution involving Al. Data from experimental runs and natural specimens indicate that the B-related OH-band can be used as a rough proxy for

  13. van der Waals forces and confinement in carbon nanopores: Interaction between CH4, COOH, NH3, OH, SH and single-walled carbon nanotubes

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    Weck, Philippe F.; Kim, Eunja; Wang, Yifeng

    2016-05-01

    Interactions between CH4, COOH, NH3, OH, SH and armchair (n, n) (n = 4, 7, 14) and zigzag (n, 0) (n = 7, 12, 25) single-walled carbon nanotubes (SWCNTs) have been systematically investigated within the framework of dispersion-corrected density functional theory (DFT-D2). Endohedral and exohedral molecular adsorption on SWCNT walls is energetically unfavorable or weak, despite the use of C6 /r6 pairwise London-dispersion corrections. The effects of pore size and chirality on the molecule/SWCNTs interaction were also assessed. Chemisorption of COOH, NH3, OH and SH at SWCNT edge sites was examined using a H-capped (7, 0) SWCNT fragment and its impact on electrophilic, nucleophilic and radical attacks was predicted by means of Fukui functions.

  14. EFFECT OF GRAIN SIZE AND ACTIVATION TIME OF ZEOLITE TO ADSORPTION AND DESORPTION OF NH4OH AND KCL AS MODEL OF FERTILIZER-ZEOLITE MIX

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    Muhammad Prasantio Bimantio

    2017-10-01

    Full Text Available Zeolites can be used as adsorbent, ion exchange, catalyst, or catalyst carrier. Application of fertilizer use in the zeolite also be one of the interesting topic. Zeolites in a mixture of fertilizer can use to control the release of nutrients. The purpose of this research is to study the effect of grain size and time of the activation of zeolite to adsorption and desorption of NH4OH and KCl as modeling of ZA and KCl fertilizer, to obtain the value of adsorption rate constant (ka and desorption rate constant (kd. This research procedure include: the process of adsorption by adding zeolite with various size and time of activation into a sealed beaker glass and let the adsorption process occurs for 24 hours. After 24 hours, the solution was filtered, the zeolite then put in 100 ml of aquadest into a sealed beaker glass and let the desorption process happened for another 24 hours. Three samples with the largest difference solution concentrations looked for the value of the ka and kd. Zeolite configuration with the largest ka is trialed with fertilizer and compared with the value of ka obtained from modeling. The result for NH4OH adsorbate, -50+60 mesh 2 hours configuration zeolite give the largest ka. For KCl adsorbate, -30+40 mesh 4 hours configuration zeolite give the largest ka. The value between modeling and trials with fertilizers are not much different.

  15. A novel process for preparation of titanium dioxide from Ti-bearing electric furnace slag: NH4HF2-HF leaching and hydrolyzing process.

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    Zheng, Fuqiang; Guo, Yufeng; Qiu, Guanzhou; Chen, Feng; Wang, Shuai; Sui, Yulei; Jiang, Tao; Yang, Lingzhi

    2018-02-15

    A novel process to prepare titanium dioxide from Ti-bearing electric furnace slag by NH 4 HF 2 -HF leaching and hydrolyzing process has been developed. In this present study, the effects of [NH 4 + ]/[F] mXolar ratio, leaching temperature, [F] concentration, liquid/solid mass ratio, leaching time on the Ti extraction, and the phase transformations have been investigated to reveal the leaching mechanism of Ti-bearing electric furnace slag in NH 4 HF 2 -HF solution. In the NH 4 HF 2 -HF leaching process, the MgTi 2 O 5 and Al 2 TiO 5 are converted to TiF 6 2- and Mg-Al-bearing precipitate. Ti extraction rate reached 98.84% under the optimal conditions. In addition, 98.25% iron ions can be removed in the presence of NaCl prior to hydrolysis process. The effects of pH and temperature on the selective hydrolysis of TiF 6 2- during hydrolysis process were also studied. In the hydrolysis process, the TiF 6 2- is converted to (NH 4 ) 2 TiOF 4 . By calcination, high grade TiO 2 powder with its purity of 99.88% was obtained, using which the products, well crystallized anatase and rutile, were obtained through roasting at 800°C and 1000°C, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A multi-level quantum mechanics and molecular mechanics study of SN2 reaction at nitrogen: NH2Cl + OH(-) in aqueous solution.

    Science.gov (United States)

    Lv, Jing; Zhang, Jingxue; Wang, Dunyou

    2016-02-17

    We employed a multi-level quantum mechanics and molecular mechanics approach to study the reaction NH2Cl + OH(-) in aqueous solution. The multi-level quantum method (including the DFT method with both the B3LYP and M06-2X exchange-correlation functionals and the CCSD(T) method, and both methods with the aug-cc-pVDZ basis set) was used to treat the quantum reaction region in different stages of the calculation in order to obtain an accurate potential of mean force. The obtained free energy activation barriers at the DFT/MM level of theory yielded a big difference of 21.8 kcal mol(-1) with the B3LYP functional and 27.4 kcal mol(-1) with the M06-2X functional respectively. Nonetheless, the barrier heights become very close when shifted from DFT to CCSD(T): 22.4 kcal mol(-1) and 22.9 kcal mol(-1) at CCSD(T)(B3LYP)/MM and CCSD(T)(M06-2X)/MM levels of theory, respectively. The free reaction energy obtained using CCSD(T)(M06-2X)/MM shows an excellent agreement with the one calculated using the available gas-phase data. Aqueous solution plays a significant role in shaping the reaction profile. In total, the water solution contributes 13.3 kcal mol(-1) and 14.6 kcal mol(-1) to the free energy barrier heights at CCSD(T)(B3LYP)/MM and CCSD(T)(M06-2X)/MM respectively. The title reaction at nitrogen is a faster reaction than the corresponding reaction at carbon, CH3Cl + OH(-).

  17. New Line Lists for Rovibrational and Rotational Transitions Within the NH X^3Σ{^-} and OH X^2Π Ground States

    Science.gov (United States)

    Brooke, James S. A.; Bernath, Peter F.; Western, Colin; Li, Gang; Groenenboom, Gerrit

    2014-06-01

    A new line list for rovibrational and rotational transitions within the NH X^3Σ{^-} ground state has been created, including line intensities in the form of Einstein A and f-values, for all possible bands up to v^'=6. The intensities are based on a new dipole moment function (DMF), which has been calculated using the internally contracted MRCI method with an aug-cc-pV6Z basis set. The programs RKR1, LEVEL and PGOPHER were used to calculate line positions and intensities using the most recent spectroscopic observations and the new DMF, and including the rotational dependence on the matrix elements. The Hund's case (b) matrix elements from the LEVEL output have been transformed to the case (a) form required by PGOPHER. Equivalent calculations have been performed for the OH X^2Π ground state. This includes a new DMF calculation using the internally contracted MR-ACPF method with an aug-cc-pV6Z basis set. A similar line list has been produced for rovibrational and rotational transitions for all possible transitions up to v^'=13.

  18. Stopped-Flow Spectrophotometric Study of the Kinetics and Mechanism of CO2 Uptake by cis-[Cr(C2O4(BaraNH2(OH22]+ Cation and the Acid-Catalyzed Decomposition of cis-[Cr(C2O4(BaraNH2OCO2]− Anion in Aqueous Solution

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    Lech Chmurzyński

    2011-09-01

    Full Text Available The kinetics of CO2 uptake by the cis-[Cr(C2O4(BaraNH2(OH22]+ complex cation and the acid hydrolysis of the cis-[Cr(C2O4(BaraNH2OCO2]− complex anion (where BaraNH2 denotes methyl 3-amino-2,3-dideoxy-b-D-arabino-hexopyranoside were studied using the stopped-flow technique. The reactions under study were investigated in aqueous solution in the 288–308 K temperature range. In the case of the reaction between CO2 and cis-[Cr(C2O4(BaraNH2(OH22]+ cation variable pH values (6.82–8.91 and the constant ionic strength of solution (H+, Na+, ClO4− = 1.0 were used. Carbon dioxide was generated by the reaction between sodium pyruvate and hydrogen peroxide. The acid hydrolysis of cis-[Cr(C2O4(BaraNH2OCO2]− was investigated for varying concentrations of H+ ions (0.01–2.7 M. The obtained results enabled the determination of the number of steps of the studied reactions. Based on the kinetic equations, rate constants were determined for each step. Finally, mechanisms for both reactions were proposed and discussed. Based on the obtained results it was concluded that the carboxylation (CO2 uptake reactions of cis-[Cr(C2O4(BaraNH2(OH22]+ and the decarboxylation (acid hydrolysis of the cis-[Cr(C2O4(BaraNH2OCO2]− are the opposite of each other.

  19. PlayDoh and Toothpicks and Gummy Bears... OH MY, They're Models!

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    Kolandaivelu, K. P.; Wilson, M. W.; Glesener, G. B.

    2017-12-01

    Simple, everyday items found around the house are often used in geoscience lab activities. Gummy bears and silly putty can model the bending and breaking behaviour of rocks; shaking buildings during an earthquake can be modeled with some Jello, toothpicks, and marshmallows; PlayDoh can be used to demonstrate layers of sedimentary rocks; and even plumbing pipes filled with pebbles and playground sand become miniature physical models of aquifers. When performed correctly, these activities can help students visualize geoscience phenomena or increase students' motivation to pay attention in class, but how do these activities help students develop ways to think like a scientist? "Developing and using models" is one of the important science and engineering practices recommended in the Next Generation Science Standards (NGSS). In this presentation, we will demonstrate a variety of common geoscience lab activities using simple, everyday household items in order to describe ways instructors can help their students develop model-based reasoning skills. Specific areas of interest will be on identifying positive and negative attributes of a model, ways to evaluate the reliability of a model, and how a model can be revised to improve its outcome. We will also outline other kinds of models that can be generated from these lab activities, such as mathematical, graphical, and verbal models. Our goal is to encourage educators to focus more time on helping students develop model-based reasoning skills, which can be used in almost all aspects of everyday life.

  20. Laboratory study on new particle formation from the reaction OH + SO2: influence of experimental conditions, H2O vapour, NH3 and the amine tert-butylamine on the overall process

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    J. Curtius

    2010-08-01

    Full Text Available Nucleation experiments starting from the reaction of OH radicals with SO2 have been performed in the IfT-LFT flow tube under atmospheric conditions at 293±0.5 K for a relative humidity of 13–61%. The presence of different additives (H2, CO, 1,3,5-trimethylbenzene for adjusting the OH radical concentration and resulting OH levels in the range (4–300 ×105 molecule cm−3 did not influence the nucleation process itself. The number of detected particles as well as the threshold H2SO4 concentration needed for nucleation was found to be strongly dependent on the counting efficiency of the used counting devices. High-sensitivity particle counters allowed the measurement of freshly nucleated particles with diameters down to about 1.5 nm. A parameterization of the experimental data was developed using power law equations for H2SO4 and H2O vapour. The exponent for H2SO4 from different measurement series was in the range of 1.7–2.1 being in good agreement with those arising from analysis of nucleation events in the atmosphere. For increasing relative humidity, an increase of the particle number was observed. The exponent for H2O vapour was found to be 3.1 representing an upper limit. Addition of 1.2×1011 molecule cm−3 or 1.2×1012 molecule cm−3 of NH3 (range of atmospheric NH3 peak concentrations revealed that NH3 has a measureable, promoting effect on the nucleation rate under these conditions. The promoting effect was found to be more pronounced for relatively dry conditions, i.e. a rise of the particle number by 1–2 orders of magnitude at RH = 13% and only by a factor of 2–5 at RH = 47% (NH3 addition: 1.2×1012 molecule cm−3. Using the amine tert-butylamine instead of NH3, the enhancing impact of the base for nucleation and particle growth appears to be stronger. Tert-butylamine addition of about 1010 molecule cm−3 at RH = 13% enhances particle formation by about two orders of magnitude, while for NH3 only a small or negligible

  1. Simulation of the time dependent infrared nu2 mode absorptions of (oH2)n:H2O clusters in O2 doped solid hydrogen at 4.2 K.

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    Abouaf-Marguin, L; Vasserot, A-M; Pardanaud, C

    2009-02-07

    Using Fourier transform infrared spectroscopy, we have analyzed the time evolution of the nu(2) mode of (oH(2))(n):H(2)O clusters (n = 11 to 1) embedded in solid normal hydrogen at 4.2 K over a period of 150 h using paramagnetic O(2) to speed up the ortho to para nuclear spin conversion process. For concentrations H(2)O/O(2)/H(2) = 1/20/4000, at time t = 0 right after the solid is prepared, all the H(2)O molecules are preferentially clustered by large numbers of oH(2). With time the cluster distribution irreversibly shifts toward smaller cluster sizes and also generates freely rotating H(2)O (n = 0) which is solvated completely by pH(2) molecules. From a spectral decomposition of the nu(2) (oH(2))(n):H(2)O cluster spectra, a phenomenological simulation of the time behavior of the clusters has been developed. The time evolution is modeled using coupled rate equations in a step by step n to n-1 cluster cascade fashion and analyzed over nine successive time periods. It shows that rotating H(2)O grows only at the expense of cluster n = 1 and that the process dramatically slows down as the conversion of orthohydrogen proceeds. At the end of the conversion process, it was found that cluster n = 1 remained with a very slow decrease.

  2. Stereodependent and solvent-specific formation of unusual β-structure through side chain-backbone H-bonding in C4(S)-(NH2/OH/NHCHO)-L-prolyl polypeptides.

    Science.gov (United States)

    Bansode, Nitin D; Madhanagopal, B; Sonar, Mahesh V; Ganesh, Krishna N

    2017-01-01

    It is shown that C4(S)-NH 2 /OH/NHCHO-prolyl polypeptides exhibit PPII conformation in aqueous medium, but in a relatively hydrophobic solvent trifluoroethanol (TFE) transform into an unusual β-structure. The stereospecific directing effect of H-bonding in defining the specific structure is demonstrated by the absence of β-structure in the corresponding C4(S)-guanidinyl/(NH/O)-acetyl derivatives and retention of β-structure in C4(S)-(NHCHO)-prolyl polypeptides in TFE. The distinct conformations are identified by the characteristic CD patterns and supported by Raman spectroscopic data. The solvent dependent conformational effects are interpreted in terms of intraresidue H-bonding that promotes PPII conformation in water, switching over to interchain H-bonding in TFE. The present observations add a new design principle to the growing repertoire of strategies for engineering peptide secondary structural motifs for innovative nanoassemblies and new biomaterials. © 2016 Wiley Periodicals, Inc.

  3. Densities and apparent molar volumes of atmospherically important electrolyte solutions. 1. The solutes H2SO4, HNO3, HCl, Na2SO4, NaNO3, NaCl, (NH4)2SO4, NH4NO3, and NH4Cl from 0 to 50 °C, including extrapolations to very low temperature and to the pure liquid state, and NaHSO4, NaOH, and NH3 at 25 °C.

    Science.gov (United States)

    Clegg, S L; Wexler, A S

    2011-04-21

    Calculations of the size and density of atmospheric aerosols are complicated by the fact that they can exist at concentrations highly supersaturated with respect to dissolved salts and supercooled with respect to ice. Densities and apparent molar volumes of solutes in aqueous solutions containing the solutes H(2)SO(4), HNO(3), HCl, Na(2)SO(4), NaNO(3), NaCl, (NH(4))(2)SO(4), NH(4)NO(3), and NH(4)Cl have been critically evaluated and represented using fitted equations from 0 to 50 °C or greater and from infinite dilution to concentrations saturated or supersaturated with respect to the dissolved salts. Using extrapolated densities of high-temperature solutions and melts, the relationship between density and concentration is extended to the hypothetical pure liquid solutes. Above a given reference concentration of a few mol kg(-1), it is observed that density increases almost linearly with decreasing temperature, and comparisons with available data below 0 °C suggest that the fitted equations for density can be extrapolated to very low temperatures. As concentration is decreased below the reference concentration, the variation of density with temperature tends to that of water (which decreases as temperature is reduced below 3.98 °C). In this region below the reference concentration, and below 0 °C, densities are calculated using extrapolated apparent molar volumes which are constrained to agree at the reference concentrations with an equation for the directly fitted density. Calculated volume properties agree well with available data at low temperatures, for both concentrated and dilute solutions. Comparisons are made with literature data for temperatures of maximum density. Apparent molar volumes at infinite dilution are consistent, on a single ion basis, to better than ±0.1 cm(3) mol(-1) from 0 to 50 °C. Volume properties of aqueous NaHSO(4), NaOH, and NH(3) have also been evaluated, at 25 °C only. In part 2 of this work (ref 1 ) an ion interaction (Pitzer

  4. Effects of the addition of H2O and NH4OH in the electrical properties of thin films of Y2O3 deposited by pyrolytic spray

    International Nuclear Information System (INIS)

    Herrera S, H.J.; Alarcon F, G.; Aguilar F, M.; Falcony, C.; Garcia H, M.; Guzman M, J.; Araiza I, J.J.

    2005-01-01

    In this work we studied the electrical properties of yttrium oxide thin films obtained by spray pyrolysis from Y(acac) 3 and N,N-DMF. The films were deposited on Si(100) substrates at temperatures of 400, 450, 500 and 550 C. The electrical characteristic of the films was improved when a mist of H 2 O and/or NH 4 0H was simultaneously added to the deposition system. Current and capacitance versus voltage measurements were obtained when the Y 2 O 3 films were integrated in MOS (Metal-Oxide-Semiconductor) structures. Y 2 O 3 films with a dielectric constant up to 15 were obtained. The films can stand electric fields up to 2 MV/cm. An interface state density in the range of 10 10 -10 11 cm -2 eV -1 was measured at midgap from the high and low frequency capacitance measurements. (Author)

  5. Synthesis, structure and magnetism of the new S  =  1 kagome magnet NH4Ni2.5V2O7(OH)2ṡH2O

    Science.gov (United States)

    Connolly, E. T.; Reeves, P.; Boldrin, D.; Wills, A. S.

    2018-01-01

    Kagome antiferromagnets (KAFMs) have long been known to host exotic electronic states due to their strong geometric frustration, including the quantum spin liquid state in S=\\frac{1}{2} systems. Away from that limit, S  =  1 KAFMs are also predicted to host unconventional ground states such as spin nematic phases, but a paucity of studies on known model materials has restricted progress. Here, we present the crystal structure and preliminary magnetization measurements on the newly synthesized S  =  1 KAFM, NH4Ni2.5V2O7(OH)_2\\cdot H2O, which has the three-fold symmetry of the kagome lattice but significant site depletion, with  ∼77% site occupancy. Bulk magnetic data show clear evidence of frustration and competition between ferromagnetic and antiferromagnetic interactions. We propose that the magnetic Hamiltonian is frustrated and that anisotropic terms cause the formation of an unconventional ground state.

  6. Effects of the addition of H2O and NH4OH in the optical and structural properties of the thin films of Y2O3 deposited by pyrolytic spray

    International Nuclear Information System (INIS)

    Alarcon F, G.; Carvajal V, R.; Aguilar F, M.; Falcony, C.

    2005-01-01

    In this work we studied the optical and structural properties of yttrium oxide thin films deposited by spray pyrolysis. Yttrium acetylacetonate was used as raw material and N, N-DMF was used as solvent. The films were deposited on Si (100) and Si (111) substrates at temperatures of 400, 450, 500 and 550 C. The optical and structural characteristics of the films were dramatically improved when a mist of H 2 O and/or NH 4 0H was simultaneously added during deposition of the films. A refraction index up to 1.88, and deposition rates lower than 10 A/sec were obtained in the films. Infrared spectroscopy measurements indicate that the films resulted free from -OH bonds. X-ray diffraction patterns reveal that the films were polycrystalline. In addition, the relative chemical composition of the films was determined by Energy Dispersive Spectroscopy and the surface morphology was analyzed in the Atomic Force Microscope. (Author)

  7. Comparison of high-titer lactic acid fermentation from NaOH- and NH3-H2O2-pretreated corncob by Bacillus coagulans using simultaneous saccharification and fermentation

    Science.gov (United States)

    Zhang, Zhenting; Xie, Yuejiao; He, Xiaolan; Li, Xinli; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Peng, Nan; Liang, Yunxiang

    2016-01-01

    Lignocellulose is one of the most abundant renewable feedstocks that has attracted considerable attention as a substrate for biofuel and biochemical production. One such biochemical product, lactic acid, is an important fermentation product because of its great potential for the production of biodegradable and biocompatible polylactic acid. High-titer lactic acid production from lignocellulosic materials has been achieved recently; however, it requires biodetoxification or results in large amounts of waste washing water. In this study, we employed two alkaline pretreatment methods and compared their effects on lactic acid fermentation of pretreated corncob by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile conditions. The lactic acid titer, yield, and productivity from 16% (w/w) NaOH-pretreated and washed corncob were 122.99 g/L, 0.77 g/g corncob, and 1.37 g/L/h, respectively, and from 16% NH3-H2O2-pretreated and washed corncob were 118.60 g/L, 0.74 g/g corncob, and 1.32 g/L/h, respectively. Importantly, the lactic acid titer, yield, and productivity from 18.4% NH3-H2O2-pretreated and unwashed corncob by using fed-batch simultaneous saccharification and fermentation reached 79.47 g/L, 0.43 g/g corncob, and 1.10 g/L/h, respectively, demonstrating that this method is possible for industrial applications and saves washing water. PMID:27853308

  8. Extractability of plutonium-238 and curium-242 from a contaminated soil as a function of pH and certain soil components. CH3COOH-NH4OH system

    International Nuclear Information System (INIS)

    Nishita, H.

    1978-01-01

    Extractability of 238 Pu and 242 Cm from an artificially contaminated soil as a function of pH and certain soil components was examined with an equilibrium batch technique by the use of a CH 3 COOH--NH 4 OH extracting system. The influence of various soil components on 238 Pu and 242 Cm extractability was determined indirectly by selective removal of the components from the soil. The soil organic matter appeared to have a major influence on the extractability of these radionuclides. Though to a lesser extent, free iron oxides exerted an influence also. Before removal of soil organic matter, the extractability curves for these radionuclides were qualitatively similar in general form. The nature of this form is discussed. Within the contaminated, untreated soil, the 238 Pu and 242 Cm extractability ranged from 0.60 to 30.8% and 0.11 to 14.83% of dose, respectively, depending on the pH of the extracting solution. The liquid-to soild-phase ratio (K'/sub d/) values ranged from 3.5 x 10 -4 to 2.7 x 10 -2 for 238 Pu and 0.9 x 10 -4 to 1.4 x 10 -2 for 242 Cm. Very low extractability occurred in the pH range from approx. 8.6 to approx. 9.7 for 238 Pu and from 7.6 to approx. 9.7 for 242 Cm

  9. Effects of the addition of H{sub 2}O and NH{sub 4}OH in the optical and structural properties of the thin films of Y{sub 2}O{sub 3} deposited by pyrolytic spray; Efectos de la adicion de H{sub 2}O y NH{sub 4}OH en las propiedades opticas y estructurales de las peliculas delgadas de Y{sub 2}O{sub 3} depositadas por rocio pirolitico

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon F, G.; Carvajal V, R.; Aguilar F, M. [CICATA-IPN, Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico); Falcony, C. [CINVESTAV, A.P. 14-740, 07000 Mexico D.F. (Mexico)] [and others

    2005-07-01

    In this work we studied the optical and structural properties of yttrium oxide thin films deposited by spray pyrolysis. Yttrium acetylacetonate was used as raw material and N, N-DMF was used as solvent. The films were deposited on Si (100) and Si (111) substrates at temperatures of 400, 450, 500 and 550 C. The optical and structural characteristics of the films were dramatically improved when a mist of H{sub 2}O and/or NH{sub 4}0H was simultaneously added during deposition of the films. A refraction index up to 1.88, and deposition rates lower than 10 A/sec were obtained in the films. Infrared spectroscopy measurements indicate that the films resulted free from -OH bonds. X-ray diffraction patterns reveal that the films were polycrystalline. In addition, the relative chemical composition of the films was determined by Energy Dispersive Spectroscopy and the surface morphology was analyzed in the Atomic Force Microscope. (Author)

  10. Axial asymmetry of the charge- and spin-density distributions in Pi states. Molecular quadrupole moments and hyperfine coupling constants of CH, NH, OH, CF, LiO, NO, and FO.

    Science.gov (United States)

    Bruna, Pablo J; Grein, Friedrich

    2009-03-19

    The axial asymmetry of the charge- and spin-density distributions in Pi states is studied via second-rank traceless tensors P(ii) (ii = xx, yy, zz), namely, quadrupole moments (Theta(ii)), electric field gradients (q(ii)), and magnetic dipolar (T(ii)) hyperfine coupling constants (hfcc's). In linear molecules, it holds that P(xx) does not = P(yy) does not = P(zz) for Pi, but P(xx) = P(yy) does not = P(zz) for Sigma, Delta, Phi,..., states. Thus, traceless P(ii) in Pi states have two independent parameters, P(parallel) = P(zz) is proportional to [r(m)(3 cos2 theta - 1] and deltaP(perpendicular) = |P(xx) - P(yy)| is proportional to [r(m) sin2 theta], with m = 2(Theta(ii)) or -3(q(ii), T(ii)). All linear states have P(parallel) does not = 0, but only Pi states exhibit deltaP(perpendicular) does not = 0, as shown by hfcc's like c = (3/2)T(zz), and d = |T(xx) - T(yy)|, as well as q0 = (-q(zz)) and |q(2)/2| = |q(xx) - q(yy)|. Little is known about Theta(zz) and deltaTheta(perpendicular) = |Theta(xx) - Theta(yy)| in Pi states since most experimental values (gas-phase) are rotational averages, and several theoretical studies have reported Theta(zz) but assumed deltaTheta(perpendicular) = 0. The diatomics studied here have X2Pi(1/2)(pi1) ground states, like CH and NO, or are of type X2Pi(3/2)(pi3), like OH, CF, LiO, and FO. The A3Pi(sigma pi3) state of NH is also included. Our P(parallel) and deltaP(perpendicular) values--calculated at the experimental R(e)'s with the B3LYP/aug-cc-pVQZ method--reproduce well the available literature data. The properties of the CF and FO radicals are not well-known so that our {c, d} and {q0, q2} values should help future experimental studies of their hyperfine spectra. Excluding OH, the complete quadrupole sets {Theta(zz), deltaTheta(perpendicular)} are new for all species discussed here. For comparison purposes, Theta(zz) of a low-lying Sigma state is also calculated for each X2Pi radical.

  11. Bulk gold catalyzed oxidation reactions of amines and isocyanides and iron porphyrin catalyzed N-H and O-H bond insertion/cyclization reactions of diamines and aminoalcohols

    Energy Technology Data Exchange (ETDEWEB)

    Klobukowski, Erik [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    conditions, it was found that the oxidative dehydrogenation of dibenzylamine to Nbenzylidenebenzylamine, with N-methylmorpholine N-oxide (NMMO), was nearly quantitative (96%) within 24 h. However, the reaction with oxygen was much slower, with only a 52% yield of imine product over the same time period. Moreover, the rate of reaction was found to be influenced by the nature of the amine N-oxide. For example, the use of the weakly basic pyridine N-oxide (PyNO) led to an imine yield of only 6% after 24 h. A comparison of amine N-oxide and O2 was also examined in the oxidation of PhCH{sub 2}OH to PhCHO catalyzed by bulk gold. In this reaction, a 52% yield of the aldehyde was achieved when NMMO was used, while only a 7% product yield was afforded when O{sub 2} was the oxidant after 48 h. The bulk gold-catalyzed oxidative dehydrogenation of cyclic amines generates amidines, which upon treatment with Aerosil and water were found to undergo hydrolysis to produce lactams. Moreover, 5-, 6-, and 7-membered lactams could be prepared through a one-pot reaction of cyclic amines by treatment with oxygen, water, bulk gold, and Aerosil. This method is much more atom economical than industrial processes, does not require corrosive acids, and does not generate undesired byproducts. Additionally, the gold and Aerosil catalysts can be readily separated from the reaction mixture. The second project involved studying iron(III) tetraphenylporphyrin chloride, Fe(TPP)Cl, as a homogeneous catalyst for the generation of carbenes from diazo reagents and their reaction with heteroatom compounds. Fe(TPP)Cl, efficiently catalyzed the insertion of carbenes derived from methyl 2-phenyldiazoacetates into O-H bonds of aliphatic and aromatic alcohols. Fe(TPP)Cl was also found to be an effective catalyst for tandem N-H and O-H insertion/cyclization reactions when 1,2-diamines and 1,2-alcoholamines were treated with diazo reagents. This approach provides a one-pot process for synthesizing piperazinones and

  12. Managing OHS

    DEFF Research Database (Denmark)

    Hull Kristensen, Peer

    2011-01-01

    Contrary to a widely held view, rather than seeing the certification of Occupational Health and Safety (OHS) as a barrier to increasing employee participation, this article views new ways of structuring participation as a necessary step towards making improvements in OHS management systems....... The article first considers how work organization has changed and then in a similar way traces how bargaining has shifted from being distributive to become integrative to create a fundamental change in the negotiation regime. Finally, by analyzing an OHS-certified firm in greater depth, the article shows how...... solutions for improvements in OHS management and notable bottom-up formulations of OHS benchmarks may help us discover how the organizational form of firms with high-performance work organization can be developed through new participatory structures....

  13. Intrinsic gas-phase reactivity toward methanol of trinuclear tungsten W(3)S(4) complexes bearing W-X (X = Br, OH) groups.

    Science.gov (United States)

    Vicent, Cristian; Feliz, Marta; Llusar, Rosa

    2008-12-11

    Electrospray ionization (ESI) tandem mass spectrometry is used to investigate the gas-phase dissociation of trinuclear sulfide W(3)S(4) complexes containing three diphosphane ligands and three terminal bromine atoms, namely, [W(3)S(4)(dmpe)(3)(Br)(3)](+) (1(+)) or hydroxo groups, [W(3)S(4)(dmpe)(3)(OH)(3)](+) (2(+)) (dmpe = 1,2-bis(dimethylphosphanyl)ethane). Sequential evaporation of two diphosphane ligands is the sole fragmentation channel for the 1(+) cation that yields product ions with one or two unsaturated W-Br functional groups, respectively. Conversely, evaporation of one diphosphane ligand followed by two water molecules is observed for cation 2(+). Complementary deuterium-labeling experiments in conjunction with computational studies provide deep insight into the thermodynamically favored product ion structures found along the fragmentation pathways. From these results, the formation of a series of cluster cations with WBr, WOH, and WO functional groups either on saturated or unsaturated metal sites is proposed. The effect of the properties of these cluster cations, among them chemical composition and coordinative saturation, on their reactivity toward methanol is discussed.

  14. Effects of the addition of H{sub 2}O and NH{sub 4}OH in the electrical properties of thin films of Y{sub 2}O{sub 3} deposited by pyrolytic spray; Efectos de la adicion de H{sub 2}O y NH{sub 4}OH en las propiedades electricas de peliculas delgadas de Y{sub 2}O{sub 3} depositadas por rocio pirolitico

    Energy Technology Data Exchange (ETDEWEB)

    Herrera S, H.J.; Alarcon F, G.; Aguilar F, M. [CICATA-IPN, Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico); Falcony, C. [CINVESTAV-IPN, 07000 Mexico D.F. (Mexico); Garcia H, M.; Guzman M, J. [IIM-UNAM, A.P. 70-360, 04510 Mexico D.F. (Mexico); Araiza I, J.J. [UAZ, 98060 Zacatecas (Mexico)

    2005-07-01

    In this work we studied the electrical properties of yttrium oxide thin films obtained by spray pyrolysis from Y(acac){sub 3} and N,N-DMF. The films were deposited on Si(100) substrates at temperatures of 400, 450, 500 and 550 C. The electrical characteristic of the films was improved when a mist of H{sub 2}O and/or NH{sub 4}0H was simultaneously added to the deposition system. Current and capacitance versus voltage measurements were obtained when the Y{sub 2}O{sub 3} films were integrated in MOS (Metal-Oxide-Semiconductor) structures. Y{sub 2}O{sub 3} films with a dielectric constant up to 15 were obtained. The films can stand electric fields up to 2 MV/cm. An interface state density in the range of 10{sup 10}-10{sup 11} cm{sup -2} eV{sup -1} was measured at midgap from the high and low frequency capacitance measurements. (Author)

  15. oh sport

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2017-03-01

    Sports play a very important and diverse role in the present-day global culture. On the occasion of the 105th anniversary of Coubertin’s Ode we would like to wish sports to return to the main words of the Ode and to correspond with them: “Oh sport, you are the peace”.

  16. Crystal structures of two decavanadates(V with pentaaquamanganese(II pendant groups: (NMe42[V10O28{Mn(H2O5}2]·5H2O and [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O

    Directory of Open Access Journals (Sweden)

    Maurício P. Franco

    2015-02-01

    Full Text Available Two heterometallic decavanadate(V compounds, bis(tetramethylammonium decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V pentahydrate, (Me4N2[V10O28{Mn(H2O5}2]·5H2O, A, and bis{[tris(hydroxymethylmethyl]ammonium} decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V dihydrate, [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O, B, have been synthesized under mild reaction conditions in an aqueous medium. Both polyanions present two [Mn(OH25]2+ complex units bound to the decavanadate cluster through oxide bridges. In A, the decavanadate unit has 2/m symmetry, whereas in B it has twofold symmetry. Apart from this, the main differences between A and B rest on the organic cations, tetramethylammonium and [tris(hydroxymethylmethyl]ammonium, respectively, and on the number and arrangement of the water molecules of crystallization. In both compounds, the H atoms from the coordinating water molecules participate in extensive three-dimensional hydrogen-bonding networks, which link the cluster units both directly and through solvent molecules and, in B, through the `tris' cation hydroxyl groups. The cation in B also participates in N—H...O hydrogen bonds. A number of C—H...O interactions are also observed in both structures.

  17. Improvement of SO2 removal by the solubility change of Ca(OH)2 in the spray dryer system.

    Science.gov (United States)

    Song, H C; Park, J W

    2001-09-01

    Experiments were carried out to verify the effect of the solubility change of the Ca(OH)2 sorbent on the removal of SO2 in a lab-scale spray dryer system. First, to identify the solubility effect, HNO3 was added into Ca(OH)2 slurry to increase the solubility of Ca(OH)2 by neutralization. The improvement of SO2 removal by 5-10% occurred under the condition of both 50% relative solubility and constant pH of slurry. But SO2 removal efficiency decreased steeply when the relative solubility approached 100% and the pH of the slurry decreased rapidly. For the practical application of the solubility effect, NH4Cl and NH4OH were selected as additives. Ammonium chloride (NH4Cl) which could improved Ca(OH)2 solubility removed more SO2 by 5-10% than NH4OH which showed no change in solubility. The optimal result was obtained when the slurry was fed at the ratio of 0.25mol NH4Cl/mol Ca(OH)2. The Ca(OH),/NH4Cl sorbent could remove more SO2 and improve Ca(OH)2 utilization than Ca(OH)2 sorbent in the Ca/S stoichiometric range of 1.0-1.4. It was concluded that the increase of sorbent solubility made the improvement in SO2 removal efficiency and Ca(OH)2 utilization.

  18. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  19. Layer-separated MoS2 bearing reduced graphene oxide formed by an in situ intercalation-cum-anchoring route mediated by Co(OH)2 as a Pt-free electrocatalyst for oxygen reduction.

    Science.gov (United States)

    Illathvalappil, Rajith; Unni, Sreekuttan M; Kurungot, Sreekumar

    2015-10-28

    A significant improvement in the electrochemical oxygen reduction reaction (ORR) activity of molybdenum sulphide (MoS2) could be accomplished by its layer separated dispersion on graphene mediated by cobalt hydroxide (Co(OH)2) through a hydrothermal process (Co(OH)2-MoS2/rGO). The activity makeover in this case is found to be originated from a controlled interplay of the favourable modulations achieved in terms of electrical conductivity, more exposure of the edge planes of MoS2 and a promotional role played by the coexistence of Co(OH)2 in the proximity of MoS2. Co(OH)2-MoS2/rGO displays an oxygen reduction onset potential of 0.855 V and a half wave potential (E1/2) of 0.731 V vs. RHE in 0.1 M KOH solution, which are much higher than those of the corresponding values (0.708 and 0.349 V, respectively) displayed by the as synthesized pristine MoS2 (P-MoS2) under identical experimental conditions. The Tafel slope corresponding to oxygen reduction for Co(OH)2-MoS2/rGO is estimated to be 63 mV dec(-1) compared to 68 mV dec(-1) displayed by the state-of-the-art Pt/C catalyst. The estimated number of electrons transferred during oxygen reduction for Co(OH)2-MoS2/rGO is in the range of 3.2-3.6 in the potential range of 0.77 V to 0.07 V, which again stands out as valid evidence on the much favourable mode of oxygen reduction accomplished by the system compared to its pristine counterpart. Overall, the present study, thus, demonstrates a viable strategy of tackling the inherent limitations, such as low electrical conductivity and limited access to the active sites, faced by the layered structures like MoS2 to position them among the group of potential Pt-free electrocatalysts for oxygen reduction.

  20. Obesity hypoventilation syndrome (OHS)

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000085.htm Obesity hypoventilation syndrome (OHS) To use the sharing features on this page, please enable JavaScript. Obesity hypoventilation syndrome (OHS) is a condition in some ...

  1. NH4Cl Treatment Prevents Tissue Calcification in Klotho Deficiency

    Science.gov (United States)

    Leibrock, Christina B.; Alesutan, Ioana; Voelkl, Jakob; Pakladok, Tatsiana; Michael, Diana; Schleicher, Erwin; Kamyabi-Moghaddam, Zahra; Quintanilla-Martinez, Leticia; Kuro-o, Makoto

    2015-01-01

    Klotho, a cofactor in suppressing 1,25(OH)2D3 formation, is a powerful regulator of mineral metabolism. Klotho-hypomorphic mice (kl/kl) exhibit excessive plasma 1,25(OH)2D3, Ca2+, and phosphate concentrations, severe tissue calcification, volume depletion with hyperaldosteronism, and early death. Calcification is paralleled by overexpression of osteoinductive transcription factor Runx2/Cbfa1, Alpl, and senescence-associated molecules Tgfb1, Pai-1, p21, and Glb1. Here, we show that NH4Cl treatment in drinking water (0.28 M) prevented soft tissue and vascular calcification and increased the life span of kl/kl mice >12-fold in males and >4-fold in females without significantly affecting extracellular pH or plasma concentrations of 1,25(OH)2D3, Ca2+, and phosphate. NH4Cl treatment significantly decreased plasma aldosterone and antidiuretic hormone concentrations and reversed the increase of Runx2/Cbfa1, Alpl, Tgfb1, Pai-1, p21, and Glb1 expression in aorta of kl/kl mice. Similarly, in primary human aortic smooth muscle cells (HAoSMCs), NH4Cl treatment reduced phosphate-induced mRNA expression of RUNX2/CBFA1, ALPL, and senescence-associated molecules. In both kl/kl mice and phosphate-treated HAoSMCs, levels of osmosensitive transcription factor NFAT5 and NFAT5-downstream mediator SOX9 were higher than in controls and decreased after NH4Cl treatment. Overexpression of NFAT5 in HAoSMCs mimicked the effect of phosphate and abrogated the effect of NH4Cl on SOX9, RUNX2/CBFA1, and ALPL mRNA expression. TGFB1 treatment of HAoSMCs upregulated NFAT5 expression and prevented the decrease of phosphate-induced NFAT5 expression after NH4Cl treatment. In conclusion, NH4Cl treatment prevents tissue calcification, reduces vascular senescence, and extends survival of klotho-hypomorphic mice. The effects of NH4Cl on vascular osteoinduction involve decrease of TGFB1 and inhibition of NFAT5-dependent osteochondrogenic signaling. PMID:25644113

  2. Post-magmatic solid solutions of CaCeAl2(Fe3+ 2/3□1/3)[Si2O7][SiO4]O(OH), allanite-(Ce) and REE-bearing epidote in miarolitic pegmatites of Permian Baveno granite (Verbania, central-southern alps, Italy)

    Science.gov (United States)

    Guastoni, Alessandro; Nestola, Fabrizio; Schiazza, Mariangela

    2017-06-01

    CaCeAl2(Fe3+ 2/3□1/3)[Si2O7][SiO4]O(OH), allanite-(Ce) and rare earth element (REE)-bearing epidote occur as globular aggregates and platy prismatic crystals in miarolitic cavities in a niobium, yttrium, fluorine (NYF) granitic pegmatite at Baveno, Verbania, Southern Alps, Italy. These samples were investigated by means of an electron probe micro-analyser (EPMA) and single-crystal X-ray diffraction. Our EPMA results show that the globular aggregates have the highest REE content in the core portion and decreases to REE-bearing epidote towards the rim whereas the prismatic crystals are characterized by marked oscillatory zoning that have the highest REE contents at the rim of the crystal. The unit-cell parameters of "allanites" have an intermediate unit-cell between CaCeAl2(Fe3+ 2/3□1/3)[Si2O7][SiO4]O(OH), allanite-(Ce) and REE-free epidote, because reflect the strong chemical heterogeneity of the samples which form complete solid solutions. Hydrothermal fluids control the activity and precipitation of incompatible elements like high field strength elements (HFSE), Sc and REE by hydrous F-rich fluids below the critical temperature which allow to deposit accessory minerals in the cavities with decreasing temperature. The source of REE and Y are the sheet and REE-silicates like siderophyllite-annite, and gadolinite-(Y) which underwent partial to complete decomposition by the activity of aggressive F-rich hydrothermal fluids.

  3. OH-6A Propulsion System Vibration Investigation

    Science.gov (United States)

    1975-01-01

    of rotors. This con- clusion, in turn, is restrained by the possibility that use of squeeze film bearing dampers (chosen to control rotor...prediction of the influence of the pendular dampers that the OH-6A uses to minimize 3/rev and 5/rev force and moments from the rotor is re- ported in...rev oscillatory forces are neglected because the pendular dampers sub- stantially reduce r’^em. The residual vertical forces introduce a small

  4. Preparation of carbon supported cobalt by electrostatic adsorption of [Co(NH[subscript 3])[subscript 6

    Energy Technology Data Exchange (ETDEWEB)

    D' Souza, L.; Regalbuto, J.R.; Miller, J.T. (BP Res. Cntr.); (UIC)

    2010-10-22

    Our previous paper [L. D'Souza, L. Jiao, J.R. Regalbuto, J.T. Miller, A.J. Kropf, J. Catal. 248 (2007) 165] presented the synthesis of cobalt catalysts on carbon (Timrex) and silica supports by strong electrostatic adsorption (SEA), using a cobalt hexaamine chloride ([Co(NH{sub 3}){sub 6}]Cl{sub 3}, CoHA) precursor. The CoHA undergoes reductive deammination in an uncontrolled manner in the presence of NaOH and adsorbs as Co{sub 3}O{sub 4} on carbon with broad size distribution. The present paper extends these studies toward the end of synthesizing well-dispersed Co oxide particles in a narrow size range on carbon supports using NH{sub 4}OH. Cobalt uptake versus pH was determined in NH{sub 4}OH and NaOH basified solutions over a number of carbons with varying point of zero charge (PZC). The resulting materials were characterized by ICP, powder XRD, XAS, TPR and STEM. CoHA in the presence of NH{sub 4}OH adsorbs as well dispersed as CoO, Co{sub 3}O{sub 4} and Co(OH){sub 4}{sup 2-} depending upon the pH of the adsorption solution. These phases were undetectable by powder XRD and STEM Z-contrast imaging, but could be identified by XAS. Additionally, non-adsorbed CoHA complexes underwent transformation to [Co(NH{sub 3}){sub 5}Cl]Cl{sub 2} at pH > 11 in solution. After calcinations of 250 C, particle sizes of Co{sub 3}O{sub 4} range from 20-50 {angstrom} from NH{sub 4}OH and 50-200 {angstrom} from NaOH. Maximum metal uptake was approximately 3.3 and 2.7 {micro}mol/m{sup 2} in presence of NaOH and NH{sub 4}OH, respectively. The SEA method of preparation was compared with incipient wetness impregnation (IWI) of Co(NO{sub 3}){sub 2}{sm_bullet}6H{sub 2}O; this method yields Co{sub 3}O{sub 4} particles after 250 C calcinations which are almost as small or in one case, smaller than the calcined SEA samples. Higher metal loadings can be achieved by the SEA method by successive adsorption steps with a little variation in particle size and distribution. However, the main

  5. Magnetic Bearing

    OpenAIRE

    Anbuselvan. T; Vinothkumar. K; Sai Vikash. M

    2013-01-01

    The use of bearings is essential to all types of machines, especially in marine aspects they provide the function of supporting heavier component in a desired position. These bearings have contact with the rotating part and causes surface wear which can be controlled by lubrication. Researches have raised the standards of performance for rotating equipment by providing robust, cost effective, easy to implement magnetic bearing solutions. Use of magnetic bearings in ships can be more advantag...

  6. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  7. OH Solar Radiometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The abundance of the hydroxyl radical, OH, determines the lifetime of methane and its global warming potential. Despite the growing importance of methane and the...

  8. Increase in Ice Nucleation Efficiency of Feldspars, Kaolinite and Mica in Dilute NH3 and NH4+-containing Solutions

    Science.gov (United States)

    Kumar, A.; Marcolli, C.; Luo, B.; Krieger, U. K.; Peter, T.

    2017-12-01

    Semivolatile species present in the atmosphere are prone to adhere to mineral dust particle surfaces during long range transport, and could potentially change the particle surface properties and its ice nucleation (IN) efficiency. Immersion freezing experiments were performed with microcline (K-feldspar), known to be highly IN active, suspended in aqueous solutions of ammonia, (NH4)2SO4, NH4HSO4, NH4NO3, NH4Cl, Na2SO4, H2SO4, K2SO4 and KCl to investigate the effect of solutes on the IN efficiency. Freezing of emulsified droplets investigated with a differential scanning calorimeter (DSC) showed that the heterogeneous ice nucleation temperatures deviate from the water activity-based IN theory, describing heterogeneous ice nucleation temperatures as a function of solution water activity by a constant offset with respect to the ice melting point curve (Zobrist et al. 2008). IN temperatures enhanced up to 4.5 K were observed for very dilute NH3 and NH4+-containing solutions while a decrease was observed as the concentration was further increased. For all solutes with cations other than NH4+, the IN efficiency decreased. An increase of the IN efficiency in very dilute NH3 and NH4+-containing solutions followed by a decrease with increasing concentration was also observed for sanidine (K-feldspar) and andesine (Na/Ca-feldspar). This is an important indication towards specific chemical interactions between solutes and the feldspar surface which is not captured by the water activity-based IN theory. A similar trend is present but less pronounced in case of kaolinite and mica, while quartz is barely affected. We hypothesize that the hydrogen bonding of NH3 molecules with surface -OH groups could be the reason for the enhanced freezing temperatures in dilute ammonia and ammonium containing solutions as they could form an ice-like overlayer providing hydrogen bonding groups for ice to nucleate on top of it. This implies to possibilities of enhanced IN efficiency, especially

  9. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  10. Thrust bearing

    Science.gov (United States)

    Anderson, W. J. (Inventor)

    1976-01-01

    A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

  11. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  12. Do aerosols act as catalysts in the OH radical initiated atmospheric oxidation of volatile organic compounds?

    Science.gov (United States)

    Sørensen, M.; Hurley, M. D.; Wallington, T. J.; Dibble, T. S.; Nielsen, O. J.

    Smog chamber/FTIR techniques were used to study the relative reactivity of OH radicals with methanol, ethanol, phenol, C 2H 4, C 2H 2, and p-xylene in 750 Torr of air diluent at 296±2 K. Experiments were performed with, and without, 500-8000 μg m -3 (4000-50 000 μm 2 cm -3 surface area per volume) of NaCl, (NH 4) 2SO 4 or NH 4NO 3 aerosol. In contrast to the recent findings of Oh and Andino (Atmospheric Environment 34 (2000) 2901, 36 (2002) 149; International Journal of Chemical Kinetics 33 (2001) 422) there was no discernable effect of aerosol on the rate of loss of the organic compounds via reaction with OH radicals. Gas kinetic theory arguments cast doubt upon the findings of Oh and Andino. The available data suggest that the answer to the title question is "No". As part of this work the rate constants for reactions of OH radicals with methanol, ethanol, and phenol in 750 Torr of air at 296 K were determined to be: kOH+CH 3OH =(8.12±0.54)×10 -13, kOH+C 2H 5OH =(3.47±0.32)×10 -12 and kOH+phenol=(3.27±0.31)×10 -11 cm 3 molecule -1 s -1.

  13. Flame Structure Studies of Neat and NH3-Doped H2/N2O/Ar Flames by Laser-Induced Fluorescence, Mass Spectrometry, and Modeling

    National Research Council Canada - National Science Library

    Sausa, R

    1998-01-01

    .... The major species concentrations are measured by molecular beam mass spectrometry (MB/MS), whereas the minor species OH, NH, and O-atom concentrations are measured by laser-induced fluorescence (LIF...

  14. Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants

    Directory of Open Access Journals (Sweden)

    Martins-Loução Maria A

    2011-05-01

    Full Text Available Abstract Background In plants, nitrate (NO3- nutrition gives rise to a natural N isotopic signature (δ15N, which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+ nutrition. When NH4+ is the major N source, the two forms, NH4+ and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g and NH4+ (aq which drives to a different δ15N. Nine plant species with different NH4+-sensitivities were cultured hydroponically with NO3- or NH4+ as the sole N sources, and plant growth and δ15N were determined. Short-term NH4+/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4+ and NH3. Results Several NO3--fed plants were consistently enriched in 15N, whereas plants under NH4+ nutrition were depleted of 15N. It was shown that more sensitive plants to NH4+ toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4+ showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4+ pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. Conclusions This article proposes that the negative values of δ15N in NH4+-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4+/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4+ may have two components: one that

  15. Synthesis of 15N-enriched urea (CO(15NH22 from 15NH3, CO, and S in a discontinuous process

    Directory of Open Access Journals (Sweden)

    C. R. Sant Ana Filho

    2012-12-01

    Full Text Available CO(15NH22 enriched with the stable isotope 15N was synthesized based on a reaction involving CO, 15NH3, and S in the presence of CH3OH. The method differs from the industrial method; a stainless steel reactor internally lined with polytetrafluoroethylene (PTFE was used in a discontinuous process under low pressure and temperature. The yield of the synthesis was evaluated as a function of the parameters: the amount of reagents, reaction time, addition of H2S, liquid solution and reaction temperature. The results showed that under optimum conditions (1.36, 4.01, and 4.48 g of 15NH3, CO, and S, respectively, 40 ml CH3OH, 40 mg H2S, 100 ºC and 120 min of reaction 1.82 g (yield 76.5% of the compound was obtained per batch. The synthesized CO(15NH22 contained 46.2% N, 0.55% biuret, melting point of 132.55 ºC and did not exhibit isotopic fractionation. The production cost of CO(15NH22 with 90.0 at. % 15N was US$ 238.60 per gram.

  16. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  17. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  18. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  19. Low Temperature Catalyst for NH3 Removal

    Science.gov (United States)

    Monje, Oscar; Melendez, Orlando

    2013-01-01

    Air revitalization technologies maintain a safe atmosphere inside spacecraft by the removal of C02, ammonia (NH3), and trace contaminants. NH3 onboard the International Space Station (ISS) is produced by crew metabolism, payloads, or during an accidental release of thermal control refrigerant. Currently, the ISS relies on removing NH3 via humidity condensate and the crew wears hooded respirators during emergencies. A different approach to cabin NH3 removal is to use selective catalytic oxidation (SCO), which builds on thermal catalytic oxidation concepts that could be incorporated into the existing TCCS process equipment architecture on ISS. A low temperature platinum-based catalyst (LTP-Catalyst) developed at KSC was used for converting NH3 to H20 and N2 gas by SCO. The challenge of implementing SCO is to reduce formation of undesirable byproducts like NOx (N20 and NO). Gas mixture analysis was conducted using FTIR spectrometry in the Regenerable VOC Control System (RVCS) Testbed. The RVCS was modified by adding a 66 L semi-sealed chamber, and a custom NH3 generator. The effect of temperature on NH3 removal using the LTP-Catalyst was examined. A suitable temperature was found where NH3 removal did not produce toxic NO, (NO, N02) and N20 formation was reduced.

  20. Laboratory procedure for sizing and electroless nickel plating assembled steel bearings

    International Nuclear Information System (INIS)

    Wright, R.R.; Petit, G.S.

    1976-01-01

    The bearing is placed in a holder and degreased in methyl chloroform. The entire bearing is etched in hydrochloric acid and sized in an ammonium bifluoride-hydrogen peroxide solution (NH 4 F.HF--H 2 O 2 ). The bearing is removed from the holder, activated in hydrochloric acid and plated with 0.001 in. of nickel in a plating tumbler immersed in a heated electroless nickel plating bath. The bearing is water-rinsed and air-dried

  1. p-Toluenesulfonic acid mediated 1,3-dipolar cycloaddition of nitroolefins with NaN3 for synthesis of 4-aryl-NH-1,2,3-triazoles.

    Science.gov (United States)

    Quan, Xue-Jing; Ren, Zhi-Hui; Wang, Yao-Yu; Guan, Zheng-Hui

    2014-11-07

    A p-TsOH-mediated 1,3-dipolar cycloaddition of nitroolefins and sodium azide for the synthesis of 4-aryl-NH-1,2,3-triazoles has been developed. p-TsOH was discovered as a vital additive in this type of 1,3-dipolar cycloaddition. This novel cycloaddition reaction is a good method for the rapid synthesis of valuable 4-aryl-NH-1,2,3-triazoles in high yields.

  2. [Study on the FTIR spectra of OH in olivines from mengyin kimberlite].

    Science.gov (United States)

    Ai, Qun; Yang, Zhi-jun; Zeng, Xiang-qing; Zheng, Yun-long; Hu, Piao-ye

    2013-09-01

    The results of FTIR spectra study of OH in olivines from Mengyin kimberlite show that there are more than 60 OH absorption peaks in the range of 3800-3000 cm(-1). We identified four major spectral features in the OH absorption bands of kimberlitic olivines. One is with nuOH in the range of 3800-3700 cm(-1), which is caused by the vapour of the room circumstance, and can not be regarded as intrinsic or non-intrinsic nuOH of the olivines. Another one is with nuOH in the range of 3710-3620 cm(-1), which belongs to three "water"-bearing minerals including serpentine, talc and Mg-bearing amphiboles, which is the non-intrinsic nuOH of the olivines. There is the possibility that H in hydrous minerals mainly entered into olivines during post-emplacement processes of the kimberlite magma. The third one is with nuOH in the range of 3620-3425 cm(-1), which originated from H occupying the Si-defect in the olivine structure, forming humite-like defects, and/or the defects that H occupies (Mg,Fe)-depletion, which is certainly attributed to the intrinsic nuOH of the olivines. In this case, H possibly entered into olivines following its immersion in the high temperature and rich fluid kimberlite magma in the mantle circumstance. The last one is with nuOH in the range of 3425-3000 cm(-1). In this area, nuOH is assigned to fluid inclusions of the olivines, and is the non-intrinsic nuOH of olivines. Fluid inclusions can enter into the olivines either during post-emplacement processes of the kimberlite magma or during the periods that olivines were formed in the mantle.

  3. Influence of NH3 on secondary organic aerosols from the ozonolysis and photooxidation of α-pinene in a flow reactor

    Science.gov (United States)

    Babar, Zaeem Bin; Park, Jun-Hyun; Lim, Ho-Jin

    2017-09-01

    This study presents detailed characterizations of a newly-developed flow reactor including (1) residence time distribution measurements, (2) relative humidity (RH) and temperature control, and (3) OH radical exposure range (i.e., atmospheric aging time). Hydroxyl (OH) radical exposures ranged from 8.20 × 1010 to 7.22 × 1011 molecules cm-3 s (0.5-4.9 d of atmospheric aging). In this study, the effects of NH3 gas on the secondary organic aerosol (SOA) formation of α-pinene by dark ozonolysis and photooxidation were investigated using the newly-developed flow reactor. For both dark α-pinene ozonolysis and photooxidation, higher SOA yields were observed in the presence of NH3 than in the absence of NH3. At RH of ∼50%, the SOA yield for ozonolysis and photooxidation in the presence of NH3 increased by 23% and 15% relative to those in the absence of NH3. Similar effects were observed at lower and higher RH conditions. Fourier transform infrared spectroscopy analysis confirmed the presence of nitrogen-containing functional groups in SOA formed in the presence of NH3. The α-pinene SOA formed in the presence of NH3 showed higher absorption and fluorescence for UV-visible radiation than those formed in the absence of NH3.

  4. Anion Effect of Zinc Source on Chemically Deposited ZnS(O,OH Films

    Directory of Open Access Journals (Sweden)

    K. Ernits

    2009-01-01

    Full Text Available The study on the anion effect of different Zn sources—Zn(CH3COO2, ZnCl2, ZnI2, Zn(NO32 and ZnSO4—on the chemical deposition of ZnS(O,OH films revealed that the growth rate and composition of the ZnS(O,OH layer depend on the instability constant (pK value of the corresponding Zn-complex Zn(Ln in the chemical bath solution. In the region of pKZn(NH32+>pKZn(Ln the ZnS(O,OH film's growth rate and ZnS concentration in films increased with the increasing pK value of the used Zn salt complex up to the pK value of the Zn[NH3]2+ complex and decreased in the region where pKZn(NH32+OH films did not depend on the Zn precursor's instability constant, the ZnS(O,OH film from zinc nitrate containing bath has higher band gap energy (Eg = 3.8 eV. The maximum efficiency of CISSe and CZTSSe monograin layer solar cells was gained with ZnS(O,OH buffer layer deposited from CBD solution containing Zn(CH3COO2 as Zn source, which provided the highest growth rate and ZnS concentration in the ZnS(O,OH film on glass substrates.

  5. Synthesis and structure of ruthenium(IV) complexes featuring N-heterocyclic ligands with an N-H group as the hydrogen-bond donor: hydrogen interactions in solution and in the solid state.

    Science.gov (United States)

    Díez, Josefina; Gimeno, José; Merino, Isabel; Rubio, Eduardo; Suárez, Francisco J

    2011-06-06

    The synthesis and characterization of novel ruthenium(IV) complexes [Ru(η(3):η(3)-C(10)H(16))Cl(2)L] [L = 3-methylpyrazole (2b), 3,5-dimethylpyrazole (2c), 3-methyl-5-phenylpyrazole (2d), 2-(1H-pyrazol-5-yl)phenol (2e), 6-azauracile (3), and 1H-indazol-3-ol (4)] are reported. Complex 2e is converted to the chelated complex [Ru(η(3):η(3)-C(10)H(16))Cl(κ(2)-N,O-2-(1H-pyrazol-3-yl)phenoxy)] (5) by treatment with an excess of NaOH. All of the ligands feature N-H, O-H, or C═O as the potential hydrogen-bonding group. The structures of complexes 2a-2c, 2e, 3, and 5 in the solid state have been determined by X-ray diffraction. Complexes 2a-2c and 3, which contain the pyrazole N-H group, exhibit intra- and intermolecular hydrogen bonds with chloride ligands [N-H···Cl distances (Å): intramolecular, 2.30-2.78; intermolecular, 2.59-2.77]. Complexes 2e and 3 bearing respectively O-H and C═O groups also feature N-H···O interactions [intramolecular (2e), 2.27 Å; intermolecular (3), 2.00 Å]. Chelated complex 5, lacking the O-H group, only shows an intramolecular N-H···Cl hydrogen bonding of 2.42 Å. The structure of complex 3, which turns out to be a dimer in the solid state through a double intermolecular N-H···O hydrogen bonding, has also been investigated in solution (CD(2)Cl(2)) by NMR diffusion studies. Diffusion-ordered spectroscopy experiments reveal an equilibrium between monomer and dimer species in solution whose extension depends on the temperature, concentration, and coordinating properties of the solvent. Preliminary catalytic studies show that complex 3 is highly active in the redox isomerization of the allylic alcohols in an aqueous medium under very mild reaction conditions (35 °C) and in the absence of a base. © 2011 American Chemical Society

  6. The OH + HBr reaction revisited

    Science.gov (United States)

    Ravishankara, A. R.; Wine, P. H.; Wells, J. R.

    1985-01-01

    Variable-temperature measurements of the rate coefficient /k(1)/ for the reaction OH + HBr yield Br + H2O are presented. The measurements are verified by two techniques: one involved a 266-nm pulsed-laser photolysis of O3/H2O/HBr/He mixtures in conjunction with time-resolved resonance fluorescence detection of OH, the second comprised pulsed laser-induced fluorescence detection of OH following 248-nm pulsed-laser photolysis of H2O2/HBr/Ar mixtures. It is reported that k(1) = (11.9 + or -1.4 x 10 to the -12th (cu cm)/(molecule)(s) independent of temperature. The measurements are compared with other available results.

  7. Volatility of NH3 from internally mixed sodium succinate-NH4SO4 particles

    Science.gov (United States)

    Wang, Na; Zhang, Yunhong

    2016-04-01

    Contributing the complicacy of atmospheric constituents, aerosol particles may undergo complicated heterogeneous reactions that have profound consequences on their hygroscopic properties and volatility. Ammonia (NH3) is a ubiquitous trace atmospheric gas in the troposphere and has negative effects on human health and climate forcing of ambient aerosols. In addition, atmospheric cycle of NH3 is complex in atmosphere, therefore it necessary to get insights to the complexity of gas-to-aerosol NH3 partitioning, which results in large uncertainties in the sources and distributions of NH3. By using in-situ Fourier transform infrared spectroscopy and attenuated total reflection (FTIR-ATR), we report here the volatility of NH3 from the laboratory generated sodium succinate with ammonium sulfate ((NH4)2SO4) at a 1:1 molar ratio as well as its effect on the hygroscopicity of the mixtures. The loss of the NH4+ peak at 1451cm-1 and the formation of peaks at 1718 and 1134 cm-1 due to C = O stretching asymmetric vibration of -COOH and ν3 (SO42-) stretching of sodium sulfate indicate that sodium succinate reacts with (NH4)2SO4, releasing NH3 and forming succinic acid and sodium sulfate on dehydration process. The formation of less hygroscopic succinic acid and volatility of NH3 in mixtures leads to a significant decrease in the total water content. To the best of our knowledge, this is the first report of the reaction between (NH4)2SO4 and dicarboxylate salts, which may represent an important particle-gas partitioning for ammonia and thus elucidate another underlying ammonia cycle in atmosphere. These results could be helpful to understand the mutual transformation process of dicarboxylic acids and dicarboxylate salts.

  8. Interaction between OHS regulation and OHS certification in Denmark

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Jørgensen, Kirsten; Jørgensen, Ulrik

    2010-01-01

    that in practice OHSAS 18001 received the same status as the Danish standards, which are presently of no practical importance. A special marking arrangement was also introduced for certified enterprises/organizations and shown on the Danish Working Environment Authority’s website. In spite of the fact that OHS...

  9. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  10. An investigation on NH 3 emissions and particulate NH 4+-NO 3- formation in East Asia

    Science.gov (United States)

    Kim, J. Y.; Song, C. H.; Ghim, Y. S.; Won, J. G.; Yoon, S. C.; Carmichael, G. R.; Woo, J.-H.

    In this study, the accuracy of NH 3 emissions in East Asia is evaluated by a comparison of measured and predicted NH 4NO 3 concentrations. For the prediction of particulate NH 4NO 3 concentrations, this study uses the USEPA Models-3/Community Multi-scale Air Quality (Models-3/CMAQ) model. The measurement data are collected from 4 ground-based stations (Beijing, Shanghai, Qingdao, and Kangwha) and ACE-ASIA C130 Flights #6, #7, and #10. The four ground-based stations and air flight tracks are located in and around the Yellow Sea in East Asia. According to the results, the predicted fine-mode NH 4+concentrations are 1.2-3.8 times overestimated compared to those measured on the mass basis, and fine-mode NO 3- concentrations are 1.9-7.6 times overestimated on the mass basis. It is also revealed in this study that aberrantly high predicted fine-mode NO 3- concentrations in East Asia can be attributed to the overestimated NH 3 emissions. The predicted gas-phase NH 3 concentrations and estimated NH 3 emissions are likely to be 1.2-3.8 times overestimated in East Asia on the mass basis. Therefore, it is recommended that approximately 20-75% reduced NH 3 emission fields should be used in future modeling studies for East Asia.

  11. Hydrothermal syntheses and crystal structure of NH

    International Nuclear Information System (INIS)

    Kang, Z. J.; Wang, Y. X.; You, F. T.; Lin, J. H.

    2001-01-01

    Ammonium rare earth fluorides NH(sub 4)Ln(sub 3)F(sub 10) (Ln=Dy, Ho, Y, Er, Tm) were synthesized by a hydrothermal method. Two polymorphs, of the hexagonal(beta)-KYb(sub 3)F(sub 10) and the cubic(gamma)-KYb(sub 3)F(sub 10) structure types, were formed under hydrothermal conditions for most of the rare earth fluorides except NH(sub 4)Dy(sub 3)F(sub 10), for which only the cubic -phase was obtained. The crystal structures of MLn(sub 3)F(sub 10) (M=alkaline metal, NH(sup+4) and Ln=rare earth) show a strong correlation to the ratio of ionic radii (R(sub M)/R(sub Ln)), which has been expressed in a structure phase diagram of the ionic radii of univalent and rare earth cations

  12. Improved gas thrust bearings

    Science.gov (United States)

    Anderson, W. J.; Etsion, I.

    1979-01-01

    Two variations of gas-lubricated thrust bearings extend substantially load-carrying range over existing gas bearings. Dual-Action Gas Thrust Bearing's load-carrying capacity is more than ninety percent greater than that of single-action bearing over range of compressibility numbers. Advantages of Cantilever-mounted Thrust Bearing are greater tolerance to dirt ingestion, good initial lift-off characteristics, and operational capability over wide temperature range.

  13. Rapid ammonia gas transport accounts for futile transmembrane cycling under NH3/NH4+ toxicity in plant roots.

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T; Li, Mingyuan; Becker, Alexander; Kronzucker, Herbert J

    2013-12-01

    Futile transmembrane NH3/NH4(+) cycling in plant root cells, characterized by extremely rapid fluxes and high efflux to influx ratios, has been successfully linked to NH3/NH4(+) toxicity. Surprisingly, the fundamental question of which species of the conjugate pair (NH3 or NH4(+)) participates in such fluxes is unresolved. Using flux analyses with the short-lived radioisotope (13)N and electrophysiological, respiratory, and histochemical measurements, we show that futile cycling in roots of barley (Hordeum vulgare) seedlings is predominately of the gaseous NH3 species, rather than the NH4(+) ion. Influx of (13)NH3/(13)NH4(+), which exceeded 200 µmol g(-1) h(-1), was not commensurate with membrane depolarization or increases in root respiration, suggesting electroneutral NH3 transport. Influx followed Michaelis-Menten kinetics for NH3 (but not NH4(+)), as a function of external concentration (Km = 152 µm, Vmax = 205 µmol g(-1) h(-1)). Efflux of (13)NH3/(13)NH4(+) responded with a nearly identical Km. Pharmacological characterization of influx and efflux suggests mediation by aquaporins. Our study fundamentally revises the futile-cycling model by demonstrating that NH3 is the major permeating species across both plasmalemma and tonoplast of root cells under toxicity conditions.

  14. A new crystal modification of diammonium hydrogen phosphate, (NH42(HPO4

    Directory of Open Access Journals (Sweden)

    Bernhard Spingler

    2010-04-01

    Full Text Available The addition of hexafluoridophosphate salts (ammonium, silver, thallium or potassium is usually used to precipitate complex cations from aqueous solutions. It has long been known that PF6− is sensitive towards hydrolysis under acidic conditions [Gebala & Jones (1969. J. Inorg. Nucl. Chem. 31, 771–776; Plakhotnyk et al. (2005. J. Fluorine Chem. 126, 27–31]. During the course of our investigation into coinage metal complexes of diphosphine ligands, we used ammonium hexafluoridophosphate in order to crystallize [Ag(diphosphine2]PF6 complexes. From these solutions we always obtained needle-like crystals which turned out to be the title compound, 2NH4+·HPO42−. It was received as the hydrolysis product of NH4PF6. The crystals are a new modification of diammonium hydrogen phosphate. In contrast to the previously published polymorph [Khan et al. (1972. Acta Cryst. B28, 2065–2069], Z′ of the title compound is 2. In the new modification of the title compound, there are eight molecules of (NH42(HPO4 in the unit cell. The structure consists of PO3OH and NH4 tetrahedra, held together by O—H...O and N—H...O hydrogen bonds.

  15. A new interaction mechanism of LiNH2 with MgH2: magnesium bond.

    Science.gov (United States)

    Yang, Xin; Li, Qingzhong; Cheng, Jianbo; Li, Wenzuo

    2013-01-01

    Quantum chemical calculations were performed for LiNH2-HMgX (X=H, F, Cl, Br, CH3, OH, and NH2) complexes to propose a new interaction mechanism between them. This theoretical survey showed that the complexes are stabilized through the combinative interaction of magnesium and lithium bonds. The binding energies are in the range of 63.2-66.5 kcal mol(-1), i.e., much larger than that of the lithium bond. Upon complexation, both Mg-H and Li-N bonds are lengthened. Substituents increase Mg-H bond elongation and at the same time decrease Li-N bond elongation. These cyclic complexes were characterized with the presence of a ring critical point and natural population analysis charges.

  16. Screening criteria for ILs used in NH

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.; Groll, Eckhard

    2016-01-01

    This paper describes a properties-optimization work for the working fluids in NH3 / ionic liquid (ILs) based single-effect absorption heat pumps. The optimum parameters of the IL can be used as criteria in screening task-specified ILs, which play the role of absorbents, in absorption heat pumps.

  17. Aquaporin 4 as a NH3 Channel

    DEFF Research Database (Denmark)

    Assentoft, Mette; Kaptan, Shreyas; Schneider, Hans-Peter

    2016-01-01

    to the aquaporins as putative NH3-permeable pores. Accordingly, a range of aquaporins from mammals, plants, fungi, and protozoans demonstrates ammonia permeability. Aquaporin 4 (AQP4) is highly expressed at perivascular glia end-feet in the mammalian brain and may, with this prominent localization at the blood-brain...

  18. Self-Assembled Hollow Spheres of β-Ni(OH) 2 and Their Derived Nanomaterials

    KAUST Repository

    Zhang, Shengmao

    2009-03-10

    This paper describes a novel solution-based chemical process to architect hollow spheres of β-Ni(OH) 2 with controllable sizes in submicrometer and micrometer regimes. In the synthesis, starting nickel salt (nitrate) is first converted to 6-coordinated nickel ion complex [Ni(EDA) 3] 2+ (bidentate ligand EDA = C 2H 4(NH 2) 2) to avoid rapid solid formation. Hollow and core - shell β-Ni(OH) 2 spheres can be obtained with this template-free approach under one-pot conditions. The β-Ni(OH) 2 spheres are constructed from petal-like nanobuilding units which in turn are formed from even smaller nanocrystallites. The obtained porous β-Ni(OH) 2 spheres have a large specific surface area and show a unimodal pore-size distribution. Several preparative parameters have been examined and optimized. In particular, the concentration of divalent nickel in the starting solutions plays an important role in controlling thickness of the petal-like β-Ni(OH) 2 flakes and diameter of spheres. The β-Ni(OH) 2 flakes self-assemble into final spherical products through a donut-like structural intermediate. Furthermore, the β-Ni(OH) 2 hollow spheres can be used as solid precursors to synthesize other nanostructured derivatives. In this work, phase pure inorganic nanostructures, carbon nanotube (CNT) - inorganic nanocomposites, and inorganic - inorganic nanocom-posites (e.g., NiO, Ni, NiO/Ni, Ni/β-Ni(OH) 2, CNTs/NiO, CNTs/Ni, Ni@CNTs, Fe(OH) 3/β-Ni(OH) 2, Co(OH) 2/β-Ni(OH) 2, and Mg(OH) 2/β-Ni(OH) 2) have been prepared via solid-state thermal decomposition, gas-phase reduction, solution-based reduction, surface oxidation, chemical vapor deposition, and liquid-phase deposition. A greater picture for general synthesis of Ni-containing nanomaterials is thus obtained. © 2009 American Chemical Society.

  19. Experiments with needle bearings

    Science.gov (United States)

    Ferretti, Pericle

    1933-01-01

    Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.

  20. NH4HCO3 gas-generating liposomal nanoparticle for photoacoustic imaging in breast cancer

    Directory of Open Access Journals (Sweden)

    Xia J

    2017-03-01

    Full Text Available Jizhu Xia, Gang Feng, Xiaorong Xia, Lan Hao, Zhigang Wang Chongqing Key Laboratory of Ultrasound Molecular Imaging, Department of Ultrasound, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China Abstract: In this study, we have developed a biodegradable nanomaterial for photoacoustic imaging (PAI. Its biodegradation products can be fully eliminated from a living organism. It is a gas-generating nanoparticle of liposome-encapsulating ammonium bicarbonate (NH4HCO3 solution, which is safe, effective, inexpensive, and free of side effects. When lasers irradiate these nanoparticles, NH4HCO3 decomposes to produce CO2, which can absorb much of the light energy under laser irradiation with a specific wavelength, and then expand under heat to generate a thermal acoustic wave. An acoustic detector can detect this wave and show it as a photoacoustic signal on a display screen. The intensity of the photoacoustic signal is enhanced corresponding to an increase in time, concentration, and temperature. During in vivo testing, nanoparticles were injected into tumor-bearing nude mice through the caudal vein, and photoacoustic signals were detected from the tumor, reaching a peak in 4 h, and then gradually disappearing. There was no damage to the skin or subcutaneous tissue from laser radiation. Our developed gas-generating nanomaterial, NH4HCO3 nanomaterial, is feasible, effective, safe, and inexpensive. Therefore, it is a promising material to be used in clinical PAI. Keywords: Photoacoustic tomography, CO2, NH4HCO3, contrast agent, cancer

  1. Detection of CH3OH J = 5→4 lines around 242 GHz from OMC-1

    International Nuclear Information System (INIS)

    Boland, W.; De Graauw, T.; Lidholm, S.; Lee, T.J.

    1983-01-01

    Sixteen methanol lines have been detected at a frequency of 242 GHz from OMC-1. They correspond to the J = 5→4, Δk = 0 transitions of CH 3 OH A and E. With the assumption of reproduced with a thermal excitation model using one temperature, T/sub exc/ = 90 K, and using a column density of N(CH 3 OH) = 5 x 10 16 cm -2 . All lines appear to be optically thin. Collisional excitation of the J = 5 levels requires gas densities of n(H 2 )> or =4 x 10 6 cm -3 . Some of the detected methanol lines are also observed at a position 2' south of OMC-1 and in DR 21, M17(SW), and W3(OH)

  2. The Dissociative Electroionization of Ammonia and Ammonia-d3. I. The NH+ and NH2+ dissociation channels.

    OpenAIRE

    Locht, Robert; Servais, Christian; Ligot, M.; Derwa, Fr.; Momigny, J.

    1988-01-01

    The dissociative electroionization of NH3 (ND3) in the NH2+ (ND2+) and NH+(ND+) dissociation channels is investigated in the 15-50 eV electron energy range. The translational energy distributions of ND2+ (NH2+) exhibit several components whereas NH+ only shows a continuous broad distribution. For both ions a kinetic energy-versus-appearance energy diagram is obtained and discussed. The predissociation of the Jahn-Teller split NH3+(A2E) state produces both ions at their lowest threshold. At hi...

  3. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... about their childhood teddy bears, and children's accounts of what they do with teddy bears, both written for school and told 'out of school', The chapter sees teddy bears as artefacts that provide a cultural channeling for the child's need of a transitional object and argues that the meanings of teddy...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  4. Evidence of amino acid precursors: C-N bond coupling in simulated interstellar CO2/NH3 ices

    Science.gov (United States)

    Esmaili, Sasan

    2015-08-01

    Low energy secondary electrons are abundantly produced in astrophysical or planetary ices by the numerous ionizing radiation fields typically encountered in space environments and may thus play a role in the radiation processing of such ices [1]. One approach to determine their chemical effect is to irradiate nanometer thick molecular solids of simple molecular constituents, with energy selected electron beams and to monitor changes in film chemistry with the surface analytical techniques [2].Of particular interest is the formation of HCN, which is a signature of dense gases in interstellar clouds, and is ubiquitous in the ISM. Moreover, the chemistry of HCN radiolysis products such as CN- may be essential to understand of the formation of amino acids [3] and purine DNA bases. Here we present new results on the irradiation of multilayer films of CO2 and NH3 with 70 eV electrons, leading to CN bond formations. The electron stimulated desorption (ESD) yields of cations and anions are recorded as a function of electron fluence. The prompt desorption of cationic reaction/scattering products [4], is observed at low fluence (~4x1013 electrons/cm2). Detected ions include C2+, C2O2+, C2O+, CO3+, C2O3+ or CO4+ from pure CO2, and N+, NH+, NH2+, NH3+, NH4+, N2+, N2H+ from pure NH3, and NO+, NOH+ from CO2/NH3 mixtures. Most saliently, increasing signals of negative ion products desorbing during prolonged irradiation of CO2/NH3 films included C2-, C2H-, C2H2-, as well as CN-, HCN- and H2CN-. The identification of particular product ions was accomplished by using 13CO2 and 15NH3 isotopes. The chemistry induced by electrons in pure films of CO2 and NH3 and mixtures with composition ratios (3:1), (1:1), and (1:3), was also studied by X-ray photoelectron spectroscopy (XPS). Irradiation of CO2/NH3 mixed films at 22 K produces species containing the following bonds/functional groups identified by XPS: C=O, O-H, C-C, C-O, C=N and N=O. (This work has been funded by NSERC).

  5. 76 FR 14802 - Establishment of Class E Airspace; Lancaster, NH

    Science.gov (United States)

    2011-03-18

    ...-1009; Airspace Docket No. 10-ANE-111] Establishment of Class E Airspace; Lancaster, NH AGENCY: Federal... at Lancaster, NH, to accommodate a new Area Navigation Global Positioning System RNAV special... establish Class E airspace at Lancaster, NH (75 FR 81517). Interested parties were invited to participate in...

  6. NH3 and (NH2)1- as ligands in yttrium metallocene chemistry.

    Science.gov (United States)

    Boshart, Monica D; Ziller, Joseph W; Evans, William J

    2018-04-03

    (C5Me5)2Y(C3H5)(THF) reacts with ammonia in THF to form the first crystallographically-characterized rare-earth metal complex with a terminal (NH2)1- ligand, (C5Me5)2Y(NH2)(THF), 1. Complex 1 can be protonated with [HNEt3][BPh4] to form [(C5Me5)2Y(NH3)(THF)][BPh4], 2. Both complexes were characterized by X-ray crystallography which allowed a comparison of the Y-NH2 bond length, 2.226(2) Å, with an Y-NH3 bond length, 2.476(2) Å, in analogous coordination environments. Reactions of 2 with NaN3 and acetone produced the known complexes [(C5Me5)2YN3]x and [(C5Me5)2Y(OCMe2)2][BPh4], respectively, suggesting that the ammonia moiety in 2 functions as a displaceable solvate like THF.

  7. OH initiated heterogeneous degradation of organophosphorus compounds

    Science.gov (United States)

    Liggio, J.; Liu, Y.; Harner, T.; Jantunen, L.; Shoeib, M.; Li, S.

    2013-12-01

    Organophosphorus compounds (OPs) have been extensively used worldwide as flame retardants, plasticizers, antifoaming agents, and additives because of their favorable physicochemical characteristics. The global consumption of OPs is likely to greatly increase due to the phasing out of bromine-containing flame retardants (BFRs) with OPs identified as possible substitutes. In most applications, OPs easily leach out of the material into the environment via volatilization, abrasion, and dissolution and have been observed widely in atmospheric particles even in polar regions. However, little is known about their atmospheric fate. The Canadian Chemicals Management Plan (CMP) has targeted OP FRs for risk assessment, including assessing stability and atmospheric transport potential of OP FRs and other priority chemicals that are associated primarily with particles. In the current study, OH initiated heterogeneous reaction kinetics of tris(1,3-dichloro-2-propyl) phosphate (TDCPP), tris-2-ethylhexyl-phosphate (TEHP), tris-2-butoxyethyl-phosphate (TBEP), and tri-phenyl phosphate (TPhP) coated on (NH4)2SO4 were investigated using a photo-chemical flow tube which was coupled to an Aerosol Mass Spectrometer (AMS) and Proton Transfer Reaction Mass Spectrometer (PTR-MS). second-order rate constants (k2) for the heterogeneous loss of TPhP, TEHP and TDCPP were (2.07×0.19)×10-12, (2.69×0.63)×10-12 and (9.22×0.92)×10-13 cm3 molecule-1 s-1, respectively, from which approximate atmospheric lifetimes were estimated to be 5.6 (5.2-6.0), 4.3 (3.5-5.6), and 12.6 (11.4-14.0) days. These results represent the first reported estimates of heterogeneous rate constants for these species, and suggest that particle bound OPEs will be highly persistent in the atmosphere, supporting the assumption that OPEs can undergo medium or long-range transport, as proposed on the basis of field measurements.

  8. O-H bond dissociation enthalpies in oximes: order restored.

    Science.gov (United States)

    Pratt, Derek A; Blake, Jessie A; Mulder, Peter; Walton, John C; Korth, Hans-Gert; Ingold, Keith U

    2004-09-01

    The O-H bond dissociation enthalpies (BDEs) of 13 oximes, RR'C=NOH, having R and/or R' = H, alkyl, and aryl are reported. Experimental anchor points used to validate the results of theoretical calculations include (1) the O-H BDEs of (t-Bu)2C=NOH, t-Bu(i-Pr)C=NOH, and t-Bu(1-Ad)C=NOH determined earlier from the heat released in the reaction of (t-Bu)2C=NO* with (PhNH)2 in benzene and EPR spectroscopy (Mahoney, L. R.; Mendenhall, G. D.; Ingold, K. U. J. Am. Chem. Soc. 1973, 95, 8610), all of which were decreased by 1.7 kcal/mol to reflect a revision to the heat of formation of (E)-azobenzene (which has significant ramifications for other BDEs) and to correct for the heat of hydrogen bonding of (t-Bu)2C=NOH (alphaH2 = 0.43 measured in this work) to benzene, and (2) the measured rates of thermal decomposition of six RR'C=NOCH2Ph at 423 or 443 K, which were used to derive O-H BDEs for the corresponding RR'C=NOH. Claims (Bordwell, F. G.; Ji, G. Z. J. Org. Chem. 1992, 57, 3019; Bordwell, F. G.; Zhang, S. J. Am. Chem. Soc. 1995, 117, 4858; and Bordwell, F. G.; Liu, W.-Z. J. Am. Chem. Soc. 1996, 118, 10819) that the O-H BDEs in mono- and diaryloximes are significantly lower than those for alkyloximes due to delocalization of the unpaired electron into the aromatic ring have always been inconsistent with the known structures of iminoxyl radicals as are the purported perpendicular structures, i.e., phi(Calpha-C=N-O*) = 90 degrees, for sterically hindered dialkyl iminoxyl radicals. The present results confirm the 1973 conclusion that simple steric effects, not electron delocalization or dramatic geometric changes, are responsible for the rather small differences in oxime O-H BDEs. Copyright 2004 American Chemical Society

  9. Crystal structure of [UO2(NH35]NO3·NH3

    Directory of Open Access Journals (Sweden)

    Patrick Woidy

    2016-12-01

    Full Text Available Pentaammine dioxide uranium(V nitrate ammonia (1/1, [UO2(NH35]NO3·NH3, was obtained in the form of yellow crystals from the reaction of caesium uranyl nitrate, Cs[UO2(NO33], and uranium tetrafluoride, UF4, in dry liquid ammonia. The [UO2]+ cation is coordinated by five ammine ligands. The resulting [UO2(NH35] coordination polyhedron is best described as a pentagonal bipyramid with the O atoms forming the apices. In the crystal, numerous N—H...N and N—H...O hydrogen bonds are present between the cation, anion and solvent molecules, leading to a three-dimensional network.

  10. NH3 and NH4+ permeability in aquaporin-expressing Xenopus oocytes

    DEFF Research Database (Denmark)

    Holm, Lars M.; Jahn, Thomas Paul; Møller, Anders Laurell Blom

    2005-01-01

    opencircuit and voltage-clamped conditions. TIP2;1 was tested as the wild-type and in a mutated version (tip2;1) in which the water permeability is intact. When AQP8-, AQP9-, AQP3- and TIP2;1-expressing oocytes were placed in a well-stirred bathing medium of low buffer capacity, NH3 permeability was evident...... inwards currents carried by NH4+. This conductivity increased as a sigmoid function of external [NH3]: for AQP8 at a bath pH (pH(e)) of 6.5, the conductance was abolished, at pH(e) 7.4 it was half maximal and at pH(e) 7.8 it saturated. NY4+ influx was associated with oocyte swelling. In comparison, native...

  11. Morphology Controlled Synthesis of α-GaO(OH Nanoparticles: Thermal Conversion to Ga2O3 and Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Ayse Dulda

    2016-01-01

    Full Text Available Morphology controlled α-GaO(OH particles have been synthesized via precipitation method which allows the tuning of relative growth rates of crystal facets. The effects of alkali addition rate and the type of alkali on the growth rates of the crystal facets during hydrolysis were also investigated. XRD and TG analysis confirmed that there was a phase transition from GaO(OH to Ga2O3 when precursor sample was calcined to 750°C. The single phase α-Ga2O3 was obtained after thermal treatment of NaOH precipitated precursor, while β-Ga2O3 was formed when the urea or NH4OH precipitated precursor was calcinated. Furthermore, the thermal, spectral, and photocatalytic properties connected to the crystal structure and morphology were discussed.

  12. Hydrogen Abstraction from Hydrocarbons by NH2.

    Science.gov (United States)

    Siddique, Kamal; Altarawneh, Mohammednoor; Gore, Jeff; Westmoreland, Phillip R; Dlugogorski, Bogdan Z

    2017-03-23

    This contribution investigates thermokinetic parameters of bimolecular gas-phase reactions involving the amine (NH 2 ) radical and a large number of saturated and unsaturated hydrocarbons. These reactions play an important role in combustion and pyrolysis of nitrogen-rich fuels, most notably biomass. Computations performed at the CBS-QB3 level and based on the conventional transition-state theory yield potential-energy surfaces and reaction rate constants, accounting for tunnelling effects and the presence of hindered rotors. In an analogy to other H abstraction systems, we demonstrate only a small influence of variational effects on the rate constants for selected reaction. The studied reactions cover the abstraction of hydrogen atoms by the NH 2 radical from the C-H bonds in C 1 -C 4 species, and four C 5 hydrocarbons of 2-methylbutane, 2-methyl-1-butene, 3-methyl-1-butene, 3-methyl-2-butene, and 3-methyl-1-butyne. For the abstraction of H from methane, in the temperature windows 300-500 and 1600-2000 K, the calculated reaction rate constants concur with the available experimental measurements, i.e., k calculated /k experimetal = 0.3-2.5 and 1.1-1.4, and the previous theoretical estimates. Abstraction of H atom from ethane attains the ratio of k calculated /k experimetal equal to 0.10-1.2 and 1.3-1.5 over the temperature windows of available experimental measurements, i.e., 300-900 K and 1500-2000 K, respectively. For the remaining alkanes (propane and n-butane), the average k experimental /k calculated ratio remains 2.6 and 1.3 over the temperature range of experimental data. Also, comparing the calculated standard enthalpy of reaction (Δ r H° 298 ) with the available experimental measurements for alkanes, we found the mean unsigned error of computations as 3.7 kJ mol -1 . This agreement provides an accuracy benchmark of our methodology, affording the estimation of the unreported kinetic parameters for H abstractions from alkenes and alkynes. On the basis of

  13. Bearings: Technology and needs

    Science.gov (United States)

    Anderson, W. J.

    1982-01-01

    A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

  14. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  15. Olefin Metathesis Mediated By: - Schiff Base Ru-Alkylidenes -Ru-Alkylidenes Bearing Unsymmetrical NH Ligands

    Science.gov (United States)

    Monsaert, Stijn; Voort, Pascal Van Der; Ledoux, Nele; Allaert, Bart; Drozdzak, Renata; Verpoort, Francis

    The classic Grubbs second-generation complex 2 was modified through 1. The introduction of a bidentate Schiff base ligand 2. Changes in the amino side groups of the NHC ligand Representative olefin metathesis test reactions show the effects induced by the ligand modifications and demonstrate some interesting new properties of the described catalysts. catalysts.

  16. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  17. Identification of 4-hydroxyheptachlorostyrene in polar bear plasma and its binding affinity to transthyretin : a metabolite of octachlorostyrene?

    NARCIS (Netherlands)

    Standau, C.D.; Meerts, I.A.T.M.; Letcher, R.J.; McAlees, A.J.; Chittim, B.; Brouwer, A.; Norstrom, R.J.

    2000-01-01

    A new compound, 4-hydroxyheptachlorostyrene (4-OH-HpCS), was identified as a major component in the chlorinated phenolic compound fraction of polar bear plasma. The structure was hypothesized to be 4-OH-HpCS based on mass spectral interpretation, the assumption that it was a metabolite of

  18. Identification of 4-hydroxyheptachlorostyrene in polar bear plasma and its binding affinity to transhyretin: a metabolite of octachlorostyrene

    NARCIS (Netherlands)

    Sandau, C.D.; Meerts, I.A.T.M.; Letcher, R.J.; McAlee, A.J.; Chittim, B.; Brouwer, A.; Norstrom, R.J.

    2000-01-01

    A new compound, 4-hydroxyheptachlorostyrene (4-OH-HpCS), was identified as a major component in the chlorinated phenolic compound fraction of polar bear plasma. The structure was hypothesized to be 4-OH-HpCS based on mass spectral interpretation, the assumption that it was a metabolite of

  19. Microwave-assisted synthesis of submicrometer GaO(OH) and Ga2O3 rods

    Science.gov (United States)

    Patra, Chitta Ranjan; Mastai, Yitzhak; Gedanken, Aharon

    2004-10-01

    Submicrometer sized gallium oxide hydroxide (GaO(OH)) and gallium oxide (Ga2O3) rods have been successfully fabricated on a large scale by refluxing an aqueous solution of Ga(NO3)3 and NH4OH in a simple domestic microwave oven (DMO). The structures, morphologies, compositions and physical properties of the as-synthesized and calcined products have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), selected area energy dispersive X-ray spectroscopy (SAEDS), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and energy dispersive X-ray (EDX) analysis. TEM images show that submicrometer sized as-synthesized Ga O(OH) rods have diameters of 0.3-0.5 μm and lengths of 3.2-3.5 μm. The calcined product consists of submicrometer rods with diameters of 0.4-0.5 μm and lengths of 5-5.5 μm. XRD, EDX and SAED analysis together indicate that the as-synthesized product has an orthorhombic gallium oxide hydroxide (GaO(OH)) crystal structure, and that the calcined product is rhombohedral Ga2O3. A possible mechanism for the formation of submicrometer sized GaO(OH) rods is discussed briefly.

  20. Heterogeneous reactions between ions NH3+and NH+andhydrocarbons adsorbed on a tungsten surface.Formation of HCN+in NH+-surface hydrocarbon collisions

    Czech Academy of Sciences Publication Activity Database

    Harnisch, M.; Scheier, P.; Herman, Zdeněk

    2015-01-01

    Roč. 392, DEC 2015 (2015), s. 139-144 ISSN 1387-3806 Institutional support: RVO:61388955 Keywords : ion-surface collisions * NH3+and NH+ projectile s * surface hydrocarbons Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.183, year: 2015

  1. Naftifine hydrochloride (NH in the treatment of pityriasis versicolor

    Directory of Open Access Journals (Sweden)

    L. P. Kotrekhova

    2016-01-01

    Full Text Available Introduction & objectives: The purpose of this study was to demonstrate the efficacy comparability of 1% NH lotion vs. of 1% NH cream (exoderil, Sandoz in the treatment of pityriasis versicolor. Material & methods. 71 patients with pityriasis versicolor were randomly allocated either to receive NH lotion once daily (NH lotion group (п = 35, 38.6 years (95% CI [33,7, 43.5] or NH cream once daily (NH cream group (п = 36, 40.8 years (95% CI [36,6, 45.0] for 14 days. Mycological evaluations (microscopy and culture were performed at weeks 2 and 3, inflammation symptoms evaluations were scored at day 3, weeks 2 and 3 after start of the therapy. Overall cure rates assessment included results of mycological, clinical outcomes and safety evaluation. Results. There was no difference between groups in mycological cure rates (94% vs 92% and inflammation regression (97% vs 97%. Overall cure rate was 91% and 92% of patients in NH lotion and NH cream groups respectively (p = 0,97. Conclusion. 1% NH lotion and 1% NH cream are effective in the treatment of pityriasis versicolor.

  2. Fluorine lubricated bearing technology

    Science.gov (United States)

    Mallaire, F. R.

    1973-01-01

    An experimental program was conducted to evaluate and select materials for ball bearings intended for use in liquid fluorine and/or FLOX. The ability of three different ball-separator materials, each containing nickel, to form and transfer a nickel fluoride film to provide effective lubrication at the required areas of a ball bearing operating in liquid fluorine was evaluated. In addition, solid lubrication of a ball bearing operating in liquid fluorine by either a fused fluoride coating applied to all surfaces of the ball separator or by a fluoride impregnation of porous sintered material ball separators was evaluated. Less bearing wear occurred when tests were conducted in the less reactive FLOX. Bearings fabricated from any of the materials tested would have relatively short wear lives and would require frequent replacement in a reusable engine.

  3. Photodissociation thresholds of OH produced from CH sub 3 OH in solid neon and argon

    CERN Document Server

    Cheng, B M; Lo, W J; Lee, Y P

    2001-01-01

    Photodissociation thresholds of OH from CH sub 3 OH in solid Ne and Ar were determined via photolysis of CH sub 3 OH/Ne and CH sub 3 OH/Ar (1/200) samples in situ at 4 K. The samples were irradiated with VUV synchrotron radiation after dispersion by a Seya-Namioka monochromator. The OH photo-product was detected by means of laser-induced fluorescence technique. The increase of fluorescent intensity of OH was monitored and recorded after the matrix sample was irradiated at different wavelengths for 3-5 min. Photodissociation threshold energies of 7.13+-0.02 eV (174.0+-0.5 nm) and 7.08+-0.04 eV (175.0+-1.0 nm) were measured for OH production of CH sub 3 OH in solid Ne and Ar, respectively.

  4. New insights into Cu/SSZ-13 SCR catalyst acidity. Part I: Nature of acidic sites probed by NH 3 titration

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jinyong; Gao, Feng; Kamasamudram, Krishna; Currier, Neal; Peden, Charles H. F.; Yezerets, Aleksey

    2017-04-01

    In this work we investigated an unusual acidity feature of a Cu/SSZ-13 catalyst used in selective catalytic reduction of NOx with NH3 (NH3-SCR). In particular, this catalyst showed two distinct NH3 desorption peaks in NH3-TPD measurements, in contrast to single, unresolved desorption peaks observed for other Cu-exchanged zeolites conventionally used in the SCR studies, including its isostructural but chemically different analogue Cu/SAPO-34. We further observed that the intensities of the two TPD peaks, which represented the amount of stored NH3, changed in opposite directions in response to progressive mild hydrothermal aging, while the total storage capacity was preserved. We proposed an explanation for this remarkable behavior, by using model reference samples and additional characterization techniques. At least three NH3 storage sites were identified: two distinct populations of Cu sites responsible for low-temperature NH3 storage, and Brønsted acid sites responsible for high-temperature NH3 storage. Contrary to the commonly accepted mechanism that Brønsted acid site loss during hydrothermal aging is driven by dealumination, we concluded that the decline in the number of Brønsted acid sites upon mild hydrothermal aging for Cu/SSZ-13 was not due to dealumination, but rather transformation of Cu sites, i.e., gradual conversion of ZCuOH (Cu2+ singly coordinated with Zeolite) to Z2Cu (Cu2+ doubly coordinated with Zeolite). This transformation was responsible for the increased low-temperature desorption peak in NH3-TPD since each ZCuOH adsorbed ~1 NH3 molecule while each Z2Cu adsorbed ~2 NH3 molecules under the conditions used here. These findings were used in Part II of this series of studies to develop a method for quantifying hydrothermal ageing of industrial Cu/SSZ-13 SCR catalysts. Authors would like to thank Randall Jines for his help with collecting the reactor data, Nancy W. Washton for measuring the NMR data and Tamas Varga for in-situ XRD measurements

  5. Flame retardants and methoxylated and hydroxylated polybrominated diphenyl ethers in two Norwegian Arctic top predators: glaucous gulls and polar bears.

    Science.gov (United States)

    Verreault, Jonathan; Gabrielsen, Geir W; Chu, Shaogang; Muir, Derek C G; Andersen, Magnus; Hamaed, Ahmad; Letcher, Robert J

    2005-08-15

    The brominated flame retardants have been subject of a particular environmental focus in the Arctic. The present study investigated the congener patterns and levels of total hexabromocyclododecane (HBCD), polybrominated biphenyls, polybrominated diphenyl ethers (PBDEs), as well as methoxylated (MeO) and hydroxylated (OH) PBDEs in plasma samples of glaucous gulls (Larus hyperboreus) and polar bears (Ursus maritimus) from the Norwegian Arctic. The analyses revealed the presence of total HBCD (0.07-1.24 ng/g wet wt) and brominated biphenyl 101 (polar bears. Sum (sigma) concentrations of the 12 PBDEs monitored in glaucous gulls (range: 8.23-67.5 ng/g wet wt) surpassed largely those of polar bears (range: 2.65-9.72 ng/g wet wt). Two higher brominated PBDEs, BDE183 and BDE209, were detected, and thus bioaccumulated to a limited degree, in glaucous gulls with concentrations ranging from polar bear plasma, BDE183 was polar bears (sigmaMeO-PBDE up to 0.17 ng/g wet wt), followed by 4'-MeO-BDE49 and 6-MeO-BDE47. The 3-OH-BDE47, 4'-OH-BDE49, and 6-OH-BDE47 congeners were also detected in glaucous gulls (sigmaOH-PBDE up to 1.05 ng/g wet wt), although in polar bears 4'-OH-BDE49 was the only congener quantifiable in 13% of the samples. The presence of MeO- and OH-PBDEs in plasma of both species suggests possible dietary uptake from naturally occurring sources (e.g., marine sponges and green algae), but also metabolically derived biotransformation of PBDEs such as BDE47 could be a contributing factor. Our findings suggest that there are dissimilar biochemical mechanisms involved in PCB and PBDE metabolism and accumulation/elimination and/or OH-PBDE accumulation and retention in glaucous gulls and polar bears.

  6. New Directions: Watching over tropospheric hydroxyl (OH)

    NARCIS (Netherlands)

    Lelieveld, J.; Brenninkmeijer, C.A.M.; Joeckel, P.; Isaksen, I.S.A.; Krol, M.C.; Mak, J.E.; Dlugokencky, E.; Montzka, S.A.; Novelli, P.C.; Peters, W.; Tans, P.P.

    2006-01-01

    Mean tropospheric hydroxyl radical (OH) abundance is often used as a measure of the oxidation capacity (or “self-cleansing”) of the atmosphere. The primary mechanism by which atmospheric pollutant gases are removed from the atmosphere is initiated by the reaction with OH. As a result, large

  7. OH masers towards IRAS 19092+0841

    Science.gov (United States)

    Edris, K. A.; Fuller, G. A.; Etoka, S.; Cohen, R. J.

    2017-12-01

    Context. Maser emission is a strong tool for studying high-mass star-forming regions and their evolutionary stages. OH masers in particular can trace the circumstellar material around protostars and determine their magnetic field strengths at milliarcsecond resolution. Aims: We seek to image OH maser emission towards high-mass protostellar objects to determine their evolutionary stages and to locate the detected maser emission in the process of high-mass star formation. Methods: In 2007, we surveyed OH maser emission towards 217 high-mass protostellar objects to study its presence. In this paper, we present follow-up MERLIN observations of a ground-state OH maser emission towards one of these objects, IRAS 19092+0841. Results: We detect emissions from the two OH main spectral lines, 1665 and 1667 MHz, close to the central object. We determine the positions and velocities of the OH maser features. The masers are distributed over a region of 5'' corresponding to 22 400 AU (or 0.1 pc) at a distance of 4.48 kpc. The polarization properties of the OH maser features are determined as well. We identify three Zeeman pairs from which we inferred a magnetic field strength of 4.4 mG pointing towards the observer. Conclusions: The relatively small velocity spread and relatively wide spacial distribution of the OH maser features support the suggestion that this object could be in an early evolutionary state before the presence of disk, jets or outflows.

  8. OHS Continues to Encourage Cardiovascular Fitness | Poster

    Science.gov (United States)

    Even on a brisk fall day, NCI at Frederick employees came out to enjoy a walk during their lunch hour at the latest Occupational Health Services (OHS) Walk for Health event. It was the third such event that OHS has sponsored in 2016.

  9. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

  10. Dissociation of NH3 and NH2D by high power CO2 laser radiation

    International Nuclear Information System (INIS)

    Jacobs, R.R.

    1976-08-01

    Multiquantum dissociation of polyatomics using intense CO 2 lasers resulting in isotopic enrichment has been demonstrated for several molecules. In this presentation, the possibility of selective dissociation of NH 3 and NH 2 D by high power laser radiation at 10 μm will be considered. Relevant work performed at the Lawrence Livermore Laboratory and elsewhere will be summarized. In this review, attention will be given to four distinct mechanisms that can play varying degrees of importance in such investigations. Discussion will deal with the usefulness of two-resonant-frequency molecular excitation, the role of buffer gases, and the need to monitor the yields into the ground and excited electronic states of the dissociated fragments

  11. Biodistribution and tumor uptake of C{sub 60}(OH){sub x} in mice

    Energy Technology Data Exchange (ETDEWEB)

    Ji Zhiqiang; Sun Hongfang, E-mail: shf@pku.edu.cn; Wang Haifang; Xie Qunying; Liu Yuangfang [Peking University, Department of Chemical Biology, College of Chemistry and Molecular Engineering (China); Wang Zheng [Chinese Academy of Medical Sciences, Cancer Institute (China)

    2006-02-15

    Radiolabeling of fullerol, {sup 125}I-C{sub 60}(OH){sub x}, was performed by the traditional chloramine-T method. The C-I covalent bond in I-C{sub 60}(OH){sub x} was characterized by X-ray photoelectron spectroscopy (XPS) that was sufficiently stable for in vivo study. Laser light scattering spectroscopy clearly showed that C{sub 60}(OH){sub x} aggregated to large nanoparticle clumps with a wide range of distribution. The clumps formed were also visualized by transmission electron microscope (TEM). We examined the biodistribution and tumor uptake of C{sub 60}(OH){sub x} in five mouse bearing tumor models, including mouse H22 hepatocarcinoma, human lung giantcellcarcinoma PD, human colon cancer HCT-8, human gastric cancer MGC803, and human OS732 osteosarcoma. The accumulation ratios of {sup 125}I-C{sub 60}(OH){sub x} in mouse H22 hepatocarcinoma to that in normal muscle tissue (T/N) and blood (T/B) at 1, 6, 24 and 72 h, reveal that {sup 125}I-C{sub 60}(OH){sub x} gradually accumulates in H22 tumor, and retains for a quite long period (e.g., T/N 3.41, T/B 3.94 at 24 h). For the other four tumor models, the T/N ratio at 24 h ranges within 1.21-6.26, while the T/B ratio ranges between 1.23 and 4.73. The accumulation of C{sub 60}(OH){sub x} in tumor is mostly due to the enhanced permeability and retention effect (EPR) and the phagocytosis of mononuclear phagocytes. Hence, C{sub 60}(OH){sub x} might serve as a photosensitizer in the photodynamic therapy of some kinds of tumor.

  12. Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Gustavson, Lisa; Ciesielski, Tomasz M.; Bytingsvik, Jenny

    2015-01-01

    As a top predator in the Arctic food chain, polar bears (Ursus maritimus) are exposed to high levels of persistent organic pollutants (POPs). Because several of these compounds have been reported to alter endocrine pathways, such as the steroidogenesis, potential disruption of the sex steroid...... synthesis by POPs may cause implications for reproduction by interfering with ovulation, implantation and fertility. Blood samples were collected from 15 female polar bears in Svalbard (Norway) in April 2008. The concentrations of nine circulating steroid hormones; dehydroepiandrosterone (DHEA......-metabolites (hydroxylated PCBs [OH-PCBs] and hydroxylated PBDEs [OH-PBDEs]), steroid hormones, biological and capture variables in female polar bears. Inverse correlations were found between circulating levels of PRE and AN, and circulating levels of OH-PCBs. There were no significant relationships between the steroid...

  13. Moessbauer study of 57Fe isolated in NH3 and NH3/Xe matrices

    International Nuclear Information System (INIS)

    Saitovitch, E.M.B.; Litterst, F.J.; Micklitz, H.

    1981-01-01

    Moessbauer studies on 57 Fe isolated in solid ammonia and ammonia/xenon mixtures were perfomed at 4.2 K and 77 K. They show clearly that atomic iron reacts only with one ammonia molecule forming FeNH 3 which is stable in an ammonia matrix up to 77 K. In addition a compound is formed which is attributed to an iron (II) hexammine. (Author) [pt

  14. LPG and NH3 Sensing Properties of SnO2 Thick Film Resistors Prepared by Screen Printing Technique

    Directory of Open Access Journals (Sweden)

    A. S. GARDE

    2010-11-01

    Full Text Available The gas sensing behavior of SnO2 thick film resistors deposited on alumina substrates has been investigated for LPG and NH3 gas. The standard screen printing technology was used to prepare the thick films. The films were fired at optimized temperature of 780 0C for 30 minutes. The material characterization was performed by XRD, SEM, FTIR, UV and EDAX for elemental analysis. IR spectroscopy analysis at 2949.26 cm-1 showed the peak assigned to the –Sn-H vibration due to the effect of hybridization i.e. sp3 and the sharp peak at 3734.31 cm-1 assigned to –Sn-OH stretching vibration due to hydrogen bonding. The variation of D.C electrical resistance of SnO2 film samples was measured in air as well as in LPG and NH3 gas atmosphere as a function of temperature. The SnO2 film samples show negative temperature coefficient of résistance. The SnO2 film samples showed the highest sensitivity to 600 ppm of LPG at 230 0C and NH3 at 370 0C. The effect of microstructure on sensitivity, response time and recovery time of the sensor in the presence of LPG and NH3 gases were studied and discussed.

  15. Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus).

    Science.gov (United States)

    Gustavson, Lisa; Ciesielski, Tomasz M; Bytingsvik, Jenny; Styrishave, Bjarne; Hansen, Martin; Lie, Elisabeth; Aars, Jon; Jenssen, Bjørn M

    2015-04-01

    As a top predator in the Arctic food chain, polar bears (Ursus maritimus) are exposed to high levels of persistent organic pollutants (POPs). Because several of these compounds have been reported to alter endocrine pathways, such as the steroidogenesis, potential disruption of the sex steroid synthesis by POPs may cause implications for reproduction by interfering with ovulation, implantation and fertility. Blood samples were collected from 15 female polar bears in Svalbard (Norway) in April 2008. The concentrations of nine circulating steroid hormones; dehydroepiandrosterone (DHEA), androstenedione (AN), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (βE2), pregnenolone (PRE) and progesterone (PRO) were determined. The aim of the study was to investigate associations among circulating levels of specific POP compounds and POP-metabolites (hydroxylated PCBs [OH-PCBs] and hydroxylated PBDEs [OH-PBDEs]), steroid hormones, biological and capture variables in female polar bears. Inverse correlations were found between circulating levels of PRE and AN, and circulating levels of OH-PCBs. There were no significant relationships between the steroid concentrations and other analyzed POPs or the variables capture date and capture location (latitude and longitude), lipid content, condition and body mass. Although statistical associations do not necessarily represent direct cause-effect relationships, the present study indicate that OH-PCBs may affect the circulating levels of AN and PRE in female polar bears and that OH-PCBs thus may interfere with the steroid homeostasis. Increase in PRO and a decrease in AN concentrations suggest that the enzyme CYP17 may be a potential target for OH-PCBs. In combination with natural stressors, ongoing climate change and contaminant exposure, it is possible that OH-PCBs may disturb the reproductive potential of polar bears. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Investigation of Bearing Technology

    National Research Council Canada - National Science Library

    Maciag, Walter

    1998-01-01

    .... They eliminate roller needles and balls in bearings. Since the GC design does not require lubrication maintenance, there is no need for the u-joint cross to contain lubrication reservoirs and distribution channels and their input fitting...

  17. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  18. Inactivation of Bacillus atrophaeus by OH radicals

    Science.gov (United States)

    Ono, Ryo; Yonetamari, Kenta; Tokumitsu, Yusuke; Yonemori, Seiya; Yasuda, Hachiro; Mizuno, Akira

    2016-08-01

    The inactivation of Bacillus atrophaeus by OH radicals is measured. This study aims to evaluate the bactericidal effects of OH radicals produced by atmospheric-pressure nonthermal plasma widely used for plasma medicine; however, in this study, OH radicals are produced by vacuum ultraviolet (VUV) photolysis of water vapor instead of plasma to allow the production of OH radicals with almost no other reactive species. A 172 nm VUV light from a Xe2 excimer lamp irradiates a He-H2O mixture flowing in a quartz tube to photodissociate H2O to produce OH, H, O, HO2, H2O2, and O3. The produced reactive oxygen species (ROS) flow out of the quartz tube nozzle to the bacteria on an agar plate and cause inactivation. The inactivation by OH radicals among the six ROS is observed by properly setting the experimental conditions with the help of simulations calculating the ROS densities. A 30 s treatment with approximately 0.1 ppm OH radicals causes visible inactivation.

  19. Sulfonation of environmental chemicals and their metabolites in the polar bear (Ursus maritimus).

    Science.gov (United States)

    Sacco, James C; James, Margaret O

    2005-09-01

    Although its habitat comprises mostly remote regions of the Arctic, the polar bear is subject to bioaccumulation of persistent environmental pollutants. Along with their phase I metabolites, they are potential substrates for detoxification via sulfonation and glucuronidation. The capability of polar bear liver to sulfonate a structurally diverse group of environmental chemicals, that is, 3-hydroxybenzo[a]pyrene (3-OH-B[a]P), triclosan, 4'-hydroxy-3,3',4,5'-tetrachlorobiphenyl (4'OH-PCB79), 4'-hydroxy-2,3,3',4,5,5'-hexachlorobiphenyl (4'-OH-PCB159), 4'-hydroxy-2,3,3',5,5',6-hexachlorobiphenyl (4'-OH-PCB165), the methoxychlor metabolite 2-(4-methoxyphenyl)-2-(4-hydroxyphenyl)-1,1,1-trichloroethane (OHMXC), tris(4-chlorophenyl)-methanol (TCPM), and pentachlorophenol (PCP) was investigated. The glucuronidation of 3-OH-B[a]P was also studied. Enzyme activity was assayed by incubation of liver cytosol or microsomes derived from three adult male polar bears with 3'-phosphoadenosine-5'-phosphosulfate or uridine 5'-diphosphoglucuronic acid and substrate, followed by fluorometric or radiochemical thin-layer chromatographic analysis. The efficiency of sulfonation decreased in the order 3-OH-B[a]P > triclosan > 4'-OH-PCB79 > OHMXC > 4'-OH-PCB165 > TCPM > 4'-OH-PCB159 > PCP, all of which produced detectable sulfate conjugates. The 3-OH-B[a]P substrate was readily sulfonated and glucuronidated (apparent K(m) 0.41, 1.4 microM, and apparent V(max) 0.50, 3.00 nmol/min/mg, respectively). UDP-glucuronic acid kinetics suggested the presence of multiple enzymes glucuronidating 3-OH-B[a]P. Substrate inhibition was observed for the sulfonation of 3-OH-B[a]P and 4'OH-PCB79 (K(i) 1.0 and 217 microM, respectively). Triclosan was the most rapidly sulfated (apparent V(max) 1008 pmol/min/mg) of the substrates tested. Since sulfonation of an acyclic tertiary alcoholic group, as in TCPM, has not previously been reported, we also examined TCPM conjugation in humans and catfish, both of which

  20. Gear bearing drive

    Science.gov (United States)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  1. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  2. State-to-state inelastic scattering of OH by HI: a comparison with OH-HCl and OH-HBr.

    Science.gov (United States)

    Moise, A; Parker, D H; ter Meulen, J J

    2007-03-28

    Relative state-to-state cross sections and steric asymmetries have been measured for the scattering process: OH (X (2)Pi(32),v=0,J=32,M(J)=32,f)+HI ((1)Sigma,v=0,JOH (X (2)Pi,v=0,Omega=12,J=12-52 and Omega=32,J=32-92,ef)+HI, at 690 cm(-1) collision energy. Comparison with the previously studied systems OH-HCl and OH-HBr reveals relevant features of the potential energy surfaces of these molecular systems. Some measured differences concerning the internal energy distribution after collision and the propensities for the impact with one or the other side of the OH molecule in scattering by HCl, HBr, and HI molecules are discussed.

  3. 44Sc-DOTA-BN[2-14]NH2 in comparison to 68Ga-DOTA-BN[2-14]NH2 in pre-clinical investigation. Is 44Sc a potential radionuclide for PET?

    International Nuclear Information System (INIS)

    Koumarianou, E.; Loktionova, N.S.; Fellner, M.; Roesch, F.; Thews, O.; Pawlak, D.; Archimandritis, S.C.; Mikolajczak, R.

    2012-01-01

    Aim: In the present study we demonstrate the in vitro and in vivo comparison of the 44 Sc and 68 Ga labeled DOTA-BN[2-14]NH 2 . 44 Sc is a positron emitter with a half life of 3.92 h. Hence it could be used for PET imaging with ligands requiring longer observation time than in the case of 68 Ga. Methods: The binding affinity of nat Sc-DOTA-BN[2-14]NH 2 and nat Ga-DOTA-BN[2-14]NH 2 to GRP receptors was studied in competition to [ 125 I-Tyr 4 ]-Bombesin in the human prostate cancer cell line PC-3. A preliminary biodistribution in normal rats was performed, while first microPET images were assessed in male Copenhagen rats bearing the androgen-independent Dunning R-3327-AT-1 prostate cancer tumor. Results: The affinity to GRP receptors in the PC-3 cell line was higher for nat Ga-DOTA-BN[2-14]NH 2 (IC 50 (nM)=0.85±0.06) than that of nat Sc-DOTA-BN[2-14]NH 2 (IC 50 (nM)=6.49±0.13). The internalization rate of 68 Ga labeled DOTA-BN[2-14]NH 2 was slower than that of 44 Sc, but their final internalization percents were comparable. 68 Ga-DOTA-BN[2-14]NH 2 was externalized faster than 44 Sc-DOTA-BN[2-14]NH 2 . The biodistribution of 44 Sc-DOTA-BN[2-14]NH 2 and 68 Ga-DOTA-BN[2-14]NH 2 in normal rats revealed a higher uptake in target organs and tissues of the first one while both excreted mainly through urinary tract. In microPET images both tracers were accumulated in the tumor with similar uptake patterns. Conclusions: Despite the differences in the receptor affinity both the 68 Ga- and the 44 Sc-labeled DOTA-BN[2-14]NH 2 tracers showed comparable distribution and similar time constants of uptake and elimination. Moreover no differences in tumor accumulation (neither in the overall uptake nor in the dynamics) were observed from the microPet imaging. From that perspective the use of either 44 Sc or 68 Ga for detecting tumors with GRP receptors is equivalent. - Highlights: ► In vitro and in vivo evaluation of 44 Sc- and 68 Ga-DOTA-BN[2-14]NH 2 in reference to published

  4. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  5. Experimental Acidification Causes Soil Base-Cation Depletion at the Bear Brook Watershed in Maine

    Science.gov (United States)

    Ivan J. Fernandez; Lindsey E. Rustad; Stephen A. Norton; Jeffrey S. Kahl; Bernard J. Cosby

    2003-01-01

    There is concern that changes in atmospheric deposition, climate, or land use have altered the biogeochemistry of forests causing soil base-cation depletion, particularly Ca. The Bear Brook Watershed in Maine (BBWM) is a paired watershed experiment with one watershed subjected to elevated N and S deposition through bimonthly additions of (NH4)2SO4. Quantitative soil...

  6. Investigating the mechanism for maintaining eucalcemia despite immobility and anuria in the hibernating American black bear (Ursus americanus).

    Science.gov (United States)

    Seger, Rita L; Cross, Randal A; Rosen, Clifford J; Causey, Robert C; Gundberg, Caren M; Carpenter, Thomas O; Chen, Tai C; Halteman, William A; Holick, Michael F; Jakubas, Walter J; Keisler, Duane H; Seger, Richard M; Servello, Frederick A

    2011-12-01

    Ursine hibernation uniquely combines prolonged skeletal unloading, anuria, pregnancy, lactation, protein recycling, and lipolysis. This study presents a radiographic and biochemical picture of bone metabolism in free-ranging, female American black bears (Ursus americanus) that were active (spring bears and autumn bears) or hibernating (hibernating bears). Hibernating bears included lactating and non-lactating individuals. We measured serum calcium, albumin, inorganic phosphate, creatinine, bone specific alkaline phosphatase (BSALP), CTX, parathyroid hormone, insulin-like growth factor-I (IGF-l), leptin, 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D] and sclerostin from 35 to 50 tranquilized hibernating bears and 14 to 35 tranquilized spring bears. We compared metacarpal cortical indices (MCI), measured by digital X-ray radiogrammetry, from 60 hunter-killed autumn bears and 79 tranquilized, hibernating bears. MCI was greater in autumn than winter in younger bears, but showed no seasonal difference in older bears. During hibernation eucalcemia was maintained, BSALP was suppressed, and CTX was in the range expected for anuria. During hibernation 1,25(OH)(2)D was produced despite anuria. 1,25(OH)(2)D and IGF-I were less in hibernating than spring bears. In a quarter of hibernating bears, sclerostin was elevated. Leptin was greater in hibernating than spring bears. In hibernating bears, leptin correlated positively with BSALP in non-lactating bears and with CTX in lactating bears. Taken together the biochemical and radiographic findings indicate that during hibernation, bone turnover was persistent, balanced, and suppressed; bone resorption was lower than expected for an unloaded skeleton; and there was no unloading-induced bone loss. The skeleton appears to perceive that it was loaded when it was actually unloaded during hibernation. However, at the level of sclerostin, the skeleton recognized that it was unloaded. During hibernation leptin

  7. The influence of Uranium-Thorium ratio and heating time during gelation using as a CCl4(NH3) on the Gel quality

    International Nuclear Information System (INIS)

    Indra-Suryawan; Sukarsono, R; Setyo-Sulardi

    1996-01-01

    Gel has been prepared from a uranium-thorium sol using CCI 4 (NH 3 ) as a gelling medium. The uranium-thorium ratio and the heating time during gelation have been chosen as variables. The sol was prepared by mixing Th(NO 3 ) 4 and UO 2 (NO 3 ) 2 solutions, heating the solution at 95 o C and adding NH 4 OH solution drop by drop until colloidal particles were formed. Sol was then fed into a gelation column containing CCI 4 (NH 3 ), where the sol was transformed into gel. A good gel has properties such as sphere in shape and elastic which it will not crack when it is dropped from 2 metres height. The experimental work resulted a good gel when the percentage of uranium was about 15 - 25 % at heating time of 40 - 50 minutes

  8. Room temperature atomic layer deposited Al2O3 on CH3NH3PbI3 characterized by synchrotron-based X-ray photoelectron spectroscopy

    Science.gov (United States)

    Kot, Małgorzata; Das, Chittaranjan; Henkel, Karsten; Wojciechowski, Konrad; Snaith, Henry J.; Schmeisser, Dieter

    2017-11-01

    An ultrathin Al2O3 film deposited on methylammonium lead triiodide (CH3NH3PbI3) perovskite has the capability to suppress the carrier recombination process and improve the perovskite solar cells efficiency and stability. However, annealing at temperatures higher than 85 °C degrades the CH3NH3PbI3 perovskite film. The X-ray photoelectron spectroscopy study performed in this work indicates that it is possible to grow Al2O3 by atomic layer deposition on the perovskite at room temperature, however, besides pure Al2O3 some OH groups are found and the creation of lead and iodine oxides at the Al2O3/CH3NH3PbI3 interface takes place.

  9. EnviroAtlas - Cleveland, OH - Block Groups

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset is the base layer for the Cleveland, OH EnviroAtlas community. The block groups are from the US Census Bureau and are included/excluded...

  10. Inversion of the OH 1720-MHz line

    International Nuclear Information System (INIS)

    Elitzur, M.

    1975-01-01

    It is shown that the OH 1720-MHz line can be strongly inverted by collisions which excite the rotation states. It is also argued that radiative pumps (of any wave length) can invert strongly only the 1612-MHz line. (author)

  11. Efficient alpha-(alkylthio)alkyl-type radical formation in (*)OH-induced oxidation of alpha-(methylthio)acetamide.

    Science.gov (United States)

    Wisniowski, Pawel B; Hug, Gordon L; Pogocki, Dariusz; Bobrowski, Krzysztof

    2010-01-14

    Pulse radiolysis with UV-vis/ESR detection and steady-state gamma-radiolysis, combined with chromatographic techniques, were used to investigate the detailed mechanism of the (*)OH-induced oxidation of alpha-(methylthio)acetamide (alpha-MTA) in aqueous solution. The main pathway involves the formation of hydroxysulfuranyl radicals alpha-MTA-(>S(*)-OH) and alpha-(alkylthio)alkyl radicals H(3)C-S-(*)CH-C( horizontal lineO)-NH(2) (lambda(max) effect of both substituents in terms of the captodative effect. At low pH, alpha-MTA-(>S(*)-OH) radicals undergo efficient conversion to intermolecularly three-electron-bonded dimeric radical cations of alpha-MTA-(>S thereforeSS(*)-OH) radicals decompose via the elimination of water, formed through intramolecular hydrogen (attached to the nitrogen atom) transfer to the hydroxysulfuranyl moiety within a six-membered structure. This process leads to the formation of the imine radical H(3)C-S-CH(2)-C( horizontal lineO)(*)NH, which subsequently decays in three independent channels. The first decay channel begins with a beta-scission followed by hydrolysis and a subsequent Hofmann rearrangement. One of the end products of this first decay channel is CO(2), which was detected. The second decay channel involves an intramolecular hydrogen transfer from the deltaC carbon atom to the radical imine site producing the alpha-(alkylthio)alkyl radical H(2)C(*)-S-CH(2)-C( horizontal lineO)-NH(2). In the third decay channel there is a 1,3-hydrogen shift in the imine radical which forms the radical H(3)C-S-(*)CH-C( horizontal lineO)-NH(2). The presence of the amide group induces more complex radical chemistry that leads unexpectedly to the degradation of the CH(3)SCH(2)CONH(2) molecule into gaseous products, CO(2) and NH(3). These features of the mechanism of the (*)OH-induced oxidation of alpha-MTA are quite different from those seen in other organic sulfides in neutral solutions.

  12. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  13. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  14. Preparation of Mg(OH){sub 2} hybrid pigment by direct precipitation and graft onto cellulose fiber via surface-initiated atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao, E-mail: wangxiao@dlpu.edu.cn [School of Textile and Materials Engineering, Dalian Polytechnic University, Dalian, Liaoning Province (China); Zhang, Yue; Lv, Lihua; Cui, Yongzhu; Wei, Chunyan [School of Textile and Materials Engineering, Dalian Polytechnic University, Dalian, Liaoning Province (China); Pang, Guibing [School of Mechanical Engineering and Automation, Dalian Polytechnic University, Dalian, Liaoning Province (China)

    2016-02-15

    Graphical abstract: - Highlights: • Adsorbed anionic dye molecules are conducive to preferential growth of (0 0 1) plane of Mg(OH){sub 2} crystal for Mg(OH){sub 2} pigments. • Uniform coverage of nanosized Mg(OH){sub 2} pigments on fiber surface is achieved via surface-initiated ATRP. • About 4 wt% of Mg(OH){sub 2} pigment on fiber surface shortens nearly half of burning time of cellulose. - Abstract: Mg(OH){sub 2} flame retardant hybrid pigment is synthesized through simultaneous solution precipitation and adsorption of anionic dyes (C.I. Acid Red 6). The Mg(OH){sub 2} hybrid pigment bearing vinyl groups after surface silane modification is immobilized onto the surface of bromo end-functional cellulose fiber by atom transfer radical polymerization (ATRP). The morphology and structure of Mg(OH){sub 2} pigments and cellulose fibers grafted with modified pigments are characterized. The thermal properties, flammability and color fastness of cellulose fibers grafted with modified pigments are measured. The results reveal that anionic dye molecules are adsorbed onto Mg(OH){sub 2} crystals and affect the formation of lamella-like Mg(OH){sub 2} crystals. The cellulose fiber grafted with modified Mg(OH){sub 2} hybrid pigment absorbs about four times heat more than original cellulose fiber with about 4% immobilization ratio of pigment, which shortens nearly half of afterflame time and afterglow time.

  15. Gas phase ultraviolet and infrared spectroscopy on a partial peptide of β2-adrenoceptor SIVSF-NH2 by a laser desorption supersonic jet technique.

    Science.gov (United States)

    Ishiuchi, Shun-Ichi; Yamada, Kohei; Oba, Hikari; Wako, Hiromichi; Fujii, Masaaki

    2016-08-17

    Laser desorption supersonic jet laser spectroscopy has been applied to a penta-peptide, Ser-Ile-Val-Ser-Phe-NH2 (SIVSF-NH2), which is a partial sequence of a binding site in a β2-adrenaline receptor protein. By comparing the resonance enhanced multiphoton ionization spectrum with the ultraviolet-ultraviolet hole burning (HB) spectrum, it is concluded that only a single conformer exists. The infrared (IR) spectrum of the X-H stretching region, measured by IR dip spectroscopy, shows that all of the OH and NH groups form hydrogen bonds. The structure of SIVSF-NH2 is assigned by the combination of a force field calculation (CONFLEX) and quantum chemical calculations both in S0 and S1. Over 20 000 stable conformations, given by CONFLEX, are classified into 6987 groups and 1068 groups in which all of the NH and OH bonds are hydrogen-bonded are selected. The most stable structure in each group was geometrically optimized by density functional theory (DFT) calculations, and theoretical IR spectra were calculated for the conformers for which the energies are within 10 kJ mol(-1) of the most stable one. It has been found that the most stable and the secondmost stable conformers well-reproduce the observed IR spectrum. The vibrational frequencies in S1 were also calculated for these two conformers. According to the reproduction of the vibrational frequencies in the HB spectrum, the structure of SIVSF-NH2 is assigned to the most stable conformer, which forms a hydrogen-bonded structure corresponding to a compact, distorted version of the beta hairpin of peptides and proteins.

  16. Generation of nanopores during desorption of NH3 from Mg(NH3)6Cl2

    DEFF Research Database (Denmark)

    Hummelshøj, Jens Strabo; Sørensen, Rasmus Zink; Kostova, M.Y.

    2006-01-01

    It is shown that nanopores are formed during desorption of NH3 from Mg(NH3)6Cl2, which has been proposed as a hydrogen storage material. The system of nanopores facilitates the transport of desorbed ammonia away from the interior of large volumes of compacted storage material. DFT calculations sh...

  17. Vibrational spectroscopic study of poldervaartite CaCa[SiO3(OH)(OH)

    Science.gov (United States)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo; Lima, Rosa Malena Fernandes

    2015-02-01

    We have studied the mineral poldervaartite CaCa[SiO3(OH)(OH)] which forms a series with its manganese analogue olmiite CaMn[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is reasonably pure and contains only calcium and manganese with low amounts of Al and F. Thermogravimetric analysis proves the mineral decomposes at 485 °C with a mass loss of 7.6% compared with the theoretical mass loss of 7.7%. A strong Raman band at 852 cm-1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm-1 are attributed to the antisymmetric vibrations. Intense prominent peaks observed at 3487, 3502, 3509, 3521 and 3547 cm-1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of poldervaartite.

  18. Radial Halbach Magnetic Bearings

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2009-01-01

    Radial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Radial Halbach magnetic bearings are based on the same principle as that of axial Halbach magnetic bearings, differing in geometry as the names of these two types of bearings suggest. Both radial and axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control. Axial Halbach magnetic bearings were described in Axial Halbach Magnetic Bearings (LEW-18066-1), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 85. In the remainder of this article, the description of the principle of operation from the cited prior article is recapitulated and updated to incorporate the present radial geometry. In simplest terms, the basic principle of levitation in an axial or radial Halbach magnetic bearing is that of the repulsive electromagnetic force between (1) a moving permanent magnet and (2) an electric current induced in a stationary electrical conductor by the motion of the magnetic field. An axial or radial Halbach bearing includes multiple permanent magnets arranged in a Halbach array ("Halbach array" is defined below) in a rotor and multiple conductors in the form of wire coils in a stator, all arranged so the rotary motion produces an axial or radial repulsion that is sufficient to levitate the rotor. A basic Halbach array (see Figure 1) consists of a row of permanent magnets, each oriented so that its magnetic field is at a right angle to that of the adjacent magnet, and the right-angle turns are sequenced so as to maximize the magnitude of the magnetic flux density on one side of the row while

  19. Crystal structure and characterization of the novel NH+⋯N hydrogen bonded polar crystal [NH2(CH2)4NH][BF4

    International Nuclear Information System (INIS)

    Wojtaś, M.; Gagor, A.; Czupiński, O.; Medycki, W.; Jakubas, R.

    2012-01-01

    Dielectric properties and phase transitions of the piperazinium tetrafluoroborate ([NH 2 (CH 2 ) 4 NH][BF 4 ], abbreviated as PFB) crystal are related to the one-dimensional arrangement of the cations linked by the bistable NH + ⋯N hydrogen bonds and molecular motions of the [BF 4 ] − units. The crystal structure of [NH 2 (CH 2 ) 4 NH][BF 4 ] is monoclinic at room temperature with the polar space group Pn. The polar/acentric properties of the room temperature phase IV have been confirmed by the piezoelectric and pyroelectric measurements. DSC measurements show that the compound undergoes three first-order structural phase transitions: at 421/411 K (heating/cooling), at 386/372 K and at 364/349 K. 1 H and 19 F NMR measurements indicate the reorientational motions of [BF 4 ] − anions and piperazinium(+) cations as well as the proton motion in the hydrogen-bonded chains of piperazine along the [001] direction. Over the phase I the isotropic reorientational motions or even self-diffusion of the cations and anions are expected. The conductivity measurements in the vicinity of the II–I PT indicate a superionic phase over the phase I. - Graphical abstract: It must be emphasized that the titled compound represents the first organic–inorganic simple salt containing the single-protonated piperazinium cation which was studied by means of the wide variety of experimental techniques. A survey of Cambridge Structural Database (CSD version 5.32 (November 2010) and updates (May 2011)) for structure containing the piperazinium cations yields 248 compounds with the doubly protonated piperazinium(2+) cations and only eight compounds with the singly protonated piperazinium(+) cations. Among these structures only one is the hybrid organic–inorganic material. This is piperazinium nitrate characterized structurally. The crystal packing of [NH 2 (CH 2 ) 4 NH][BF 4 ], phase IV. The dashed lines stand for the hydrogen bonds. The hydrogen bonds to BF4 groups are not included for

  20. Crystal structure and characterization of the novel NH+⋯N hydrogen bonded polar crystal [NH2(CH2)4NH][BF4

    Science.gov (United States)

    Wojtaś, M.; Gaģor, A.; Czupiński, O.; Medycki, W.; Jakubas, R.

    2012-03-01

    Dielectric properties and phase transitions of the piperazinium tetrafluoroborate ([NH2(CH2)4NH][BF4], abbreviated as PFB) crystal are related to the one-dimensional arrangement of the cations linked by the bistable NH+⋯N hydrogen bonds and molecular motions of the [BF4]- units. The crystal structure of [NH2(CH2)4NH][BF4] is monoclinic at room temperature with the polar space group Pn. The polar/acentric properties of the room temperature phase IV have been confirmed by the piezoelectric and pyroelectric measurements. DSC measurements show that the compound undergoes three first-order structural phase transitions: at 421/411 K (heating/cooling), at 386/372 K and at 364/349 K. 1H and 19F NMR measurements indicate the reorientational motions of [BF4]- anions and piperazinium(+) cations as well as the proton motion in the hydrogen-bonded chains of piperazine along the [001] direction. Over the phase I the isotropic reorientational motions or even self-diffusion of the cations and anions are expected. The conductivity measurements in the vicinity of the II-I PT indicate a superionic phase over the phase I.

  1. Bioaccumulation and biotransformation of brominated and chlorinated contaminants and their metabolites in ringed seals (Pusa hispida) and polar bears (Ursus maritimus) from East Greenland.

    Science.gov (United States)

    Letcher, Robert J; Gebbink, Wouter A; Sonne, Christian; Born, Erik W; McKinney, Melissa A; Dietz, Rune

    2009-11-01

    We report on the comparative bioaccumulation, biotransformation and/or biomagnification from East Greenland ringed seal (Pusa hispida) blubber to polar bear (Ursus maritimus) tissues (adipose, liver and brain) of various classes and congeners of persistent chlorinated and brominated contaminants and metabolic by-products: polychlorinated biphenyls (PCBs), chlordanes (CHLs), hydroxyl (OH-) and methylsulfonyl (MeSO(2)-) PCBs, polybrominated biphenyls (PBBs), OH-PBBs, polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) flame retardants and OH- and methoxyl (MeO-) PBDEs, 2,2-dichloro-bis(4-chlorophenyl)ethene (p,p'-DDE), 3-MeSO(2)-p,p'-DDE, pentachlorophenol (PCP) and 4-OH-heptachlorostyrene (4-OH-HpCS). We detected all of the investigated contaminants in ringed seal blubber with high frequency, the main diet of East Greenland bears, with the exception of OH-PCBs and 4-OH-HpCS, which indicated that these phenolic contaminants were likely of metabolic origin and formed in the bears from accumulated PCBs and octachlorostyrene (OCS), respectively, rather than being bioaccumulated from a seal blubber diet. For all of the detectable sum of classes or individual organohalogens, in general, the ringed seal to polar bear mean BMFs for SigmaPCBs, p,p'-DDE, SigmaCHLs, SigmaMeSO(2)-PCBs, 3-MeSO(2)-p,p'-DDE, PCP, SigmaPBDEs, total-(alpha)-HBCD, SigmaOH-PBDEs, SigmaMeO-PBDEs and SigmaOH-PBBs indicated that these organohalogens bioaccumulate, and in some cases there was tissue-specific biomagnification, e.g., BMFs for bear adipose and liver ranged from 2 to 570. The blood-brain barrier appeared to be effective in minimizing brain accumulation as BMFs were bear tissues appeared to be mainly accumulated from the seal blubber rather than being metabolic formed from PBDEs in the bears. In vitro PBDE depletion assays using polar bear hepatic microsomes, wherein the rate of oxidative metabolism of PBDE congeners was very slow, supported the probability that accumulation

  2. Hybrid superconductor magnet bearings

    Science.gov (United States)

    Chu, Wei-Kan

    1995-01-01

    Hybrid superconductor magnet bearings (HSMB's) utilize high temperature superconductors (HTS's) together with permanent magnets to form a frictionless interface between relatively rotating parts. They are low mass, stable, and do not incur expenditure of energy during normal operation. There is no direct physical contact between rotor and stator, and hence there is no wear and tear. However, just as any other applications of HTS's, it requires a very cold temperature to function. Whereas this might be perceived as a disadvantage on earth, it is of no great concern in space or on the moon. To astronomers, the moon is an excellent site for an observatory, but the cold and dusty vacuum environment on the moon precludes the use of mechanical bearings on the telescope mounts. Furthermore, drive mechanisms with very fine steps, and hence bearings with extremely low friction are needed to track a star from the moon, because the moon rotates very slowly. All aspects considered, the HSMB is about the only candidate that fits in naturally. Here, we present a design for one such bearing, capable of supporting a telescope that weighs about 3 lbs on Earth.

  3. Exploring the crystallization landscape of cadmium bis(N-hydroxyethyl, N-isopropyldithiocarbamate), Cd[S2CN(iPr)CH2CH2OH]2

    International Nuclear Information System (INIS)

    Tan, Yee Seng; Halim, Siti Nadiah Abdul; Tiekink, Edward R.T.; Sunway Univ., Bandar Sunway

    2016-01-01

    Crystallization of Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 from ethanol yields the coordination polymer [{Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 }.EtOH] ∞ (1) within 3 h. When the solution is allowed to stand for another hour, the needles begin to dissolve and prisms emerge of the supramolecular isomer (SI), binuclear {Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 } 2 .2EtOH (2). These have been fully characterized spectroscopically and by X-ray crystallography. Polymeric 1 has 2-fold symmetry and features dithiocarbamate ligands coordinating two octahedral Cd atoms in a μ 2 κ 2 -tridentate mode. Binuclear 2 is centrosymmetric with two ligands being μ 2 κ 2 -tridentate as for 1 but the other two being κ 2 -chelating leading to square pyramidal geometries. The conversion of the kinetic crystallization product, 1, to thermodynamic 2 is irreversible but transformations mediated by recrystallization (ethanol and acetonitrile) to related literature SI species, namely coordination polymer [{Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 } 3 .MeCN] ∞ and binuclear {Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 } 2 .2H 2 O.2MeCN, are demonstrated, some of which are reversible. Three other crystallization outcomes are described whereby crystal structures were obtained for the 1:2 co-crystal {Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 } 2 :2[3-(propan-2-yl)-1,3-oxazolidine-2-thione] (3), the salt co-crystal [iPrNH 2 (CH 2 CH 2 OH)] 4 [SO 4 ] 2 {Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 } 2 (4) and the salt [iPrNH 2 (CH 2 CH 2 OH)]{Cd[S 2 CN(iPr)CH 2 CH 2 OH] 3 } (5). These arise as a result of decomposition/oxidation of the dithiocarbamate ligands. In each of 3 and 4 the binuclear {Cd[S 2 CN(iPr)CH 2 CH 2 OH] 2 } 2 SI, as in 2, is observed strongly suggesting a thermodynamic preference for this form.

  4. Tissue-specific congener composition of organohalogen and metabolite contaminants in East Greenland polar bears (Ursus maritimus)

    Energy Technology Data Exchange (ETDEWEB)

    Gebbink, Wouter A. [National Wildlife Research Centre, Science and Technology Branch, Environment Canada, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Sonne, Christian; Dietz, Rune; Kirkegaard, Maja; Riget, Frank F. [Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Born, Erik W. [Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk, Greenland (Denmark); Muir, Derek C.G. [Water Science and Technology Directorate, Environment Canada, Burlington, Ontario L7R 4A6 (Canada); Letcher, Robert J. [National Wildlife Research Centre, Science and Technology Branch, Environment Canada, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6 (Canada)], E-mail: robert.letcher@ec.gc.ca

    2008-04-15

    Congener patterns of the major organohalogen contaminant classes of PCBs, PBDEs and their metabolites and/or by-products (OH-PCBs, MeSO{sub 2}-PCBs, OH-PBDEs and MeO-PBDEs) were examined in adipose tissue, liver, brain and blood of East Greenland polar bears (Ursus maritimus). PCB, OH-PCB, MeSO{sub 2}-PCB and PBDE congener patterns showed significant differences (p {<=} 0.05) mainly in the liver and the brain relative to the adipose tissue and the blood. OH-PBDEs and MeO-PBDEs were not detected in the brain and liver, but had different patterns in blood versus the adipose tissue. Novel OH-polybrominated biphenyls (OH-PBBs), one tri- and two tetra-brominated OH-PBBs were detected in all tissues and blood. Congener pattern differences among tissues and blood are likely due to a combination of factors, e.g., biotransformation and retention in the liver, retention in the blood and blood-brain barrier transport. Our findings suggest that different congener pattern exposures to these classes of contaminants should be considered with respect to potential target tissue-specific effects in East Greenland polar bears. - Tissues-specific (adipose tissue, liver, brain and blood) differences exist for the congener patterns of PCBs, PBDEs and their metabolites/degradation products in East Greenland polar bears.

  5. Tissue-specific congener composition of organohalogen and metabolite contaminants in East Greenland polar bears (Ursus maritimus)

    International Nuclear Information System (INIS)

    Gebbink, Wouter A.; Sonne, Christian; Dietz, Rune; Kirkegaard, Maja; Riget, Frank F.; Born, Erik W.; Muir, Derek C.G.; Letcher, Robert J.

    2008-01-01

    Congener patterns of the major organohalogen contaminant classes of PCBs, PBDEs and their metabolites and/or by-products (OH-PCBs, MeSO 2 -PCBs, OH-PBDEs and MeO-PBDEs) were examined in adipose tissue, liver, brain and blood of East Greenland polar bears (Ursus maritimus). PCB, OH-PCB, MeSO 2 -PCB and PBDE congener patterns showed significant differences (p ≤ 0.05) mainly in the liver and the brain relative to the adipose tissue and the blood. OH-PBDEs and MeO-PBDEs were not detected in the brain and liver, but had different patterns in blood versus the adipose tissue. Novel OH-polybrominated biphenyls (OH-PBBs), one tri- and two tetra-brominated OH-PBBs were detected in all tissues and blood. Congener pattern differences among tissues and blood are likely due to a combination of factors, e.g., biotransformation and retention in the liver, retention in the blood and blood-brain barrier transport. Our findings suggest that different congener pattern exposures to these classes of contaminants should be considered with respect to potential target tissue-specific effects in East Greenland polar bears. - Tissues-specific (adipose tissue, liver, brain and blood) differences exist for the congener patterns of PCBs, PBDEs and their metabolites/degradation products in East Greenland polar bears

  6. Reflectance spectroscopy (0.35–8 μm) of ammonium-bearing minerals and qualitative comparison to Ceres-like asteroids

    Science.gov (United States)

    Berg, Breanne L.; Cloutis, Edward A.; Beck, P.; Vernazza, P.; Bishop, Janice L; Takir, Driss; Reddy, V.; Applin, D.; Mann, Paul

    2016-01-01

    Ammonium-bearing minerals have been suggested to be present on Mars, Ceres, and various asteroids and comets. We undertook a systematic study of the spectral reflectance properties of ammonium-bearing minerals and compounds that have possible planetary relevance (i.e., ammonium carbonates, chlorides, nitrates, oxalates, phosphates, silicates, and sulfates). Various synthetic and natural NH4+-bearing minerals were analyzed using reflectance spectroscopy in the long-wave ultraviolet, visible, near-infrared, and mid-infrared regions (0.35–8 μm) in order to identify spectral features characteristic of the NH4+ molecule, and to evaluate if and how these features vary among different species. Mineral phases were confirmed through structural and compositional analyses using X-ray diffraction, X-ray fluorescence, and elemental combustion analysis. Characteristic absorption features associated with NH4 can be seen in the reflectance spectra at wavelengths as short as ∼1 μm. In the near-infrared region, the most prominent absorption bands are located near 1.6, 2.0, and 2.2 μm. Absorption features characteristic of NH4+ occurred at slightly longer wavelengths in the mineral-bound NH4+ spectra than for free NH4+ for most of the samples. Differences in wavelength position are attributable to various factors, including differences in the type and polarizability of the anion(s) attached to the NH4+, degree and type of hydrogen bonding, molecule symmetry, and cation substitutions. Multiple absorption features, usually three absorption bands, in the mid-infrared region between ∼2.8 and 3.8 μm were seen in all but the most NH4-poor sample spectra, and are attributed to fundamentals, combinations, and overtones of stretching and bending vibrations of the NH4+ molecule. These features appear even in reflectance spectra of water-rich samples which exhibit a strong 3 μm region water absorption feature. While many of the samples examined in this study have NH4 absorption

  7. Reflectance spectroscopy (0.35-8 μm) of ammonium-bearing minerals and qualitative comparison to Ceres-like asteroids

    Science.gov (United States)

    Berg, Breanne L.; Cloutis, Edward A.; Beck, Pierre; Vernazza, Pierre; Bishop, Janice L.; Takir, Driss; Reddy, Vishnu; Applin, Daniel; Mann, Paul

    2016-02-01

    Ammonium-bearing minerals have been suggested to be present on Mars, Ceres, and various asteroids and comets. We undertook a systematic study of the spectral reflectance properties of ammonium-bearing minerals and compounds that have possible planetary relevance (i.e., ammonium carbonates, chlorides, nitrates, oxalates, phosphates, silicates, and sulfates). Various synthetic and natural NH4+-bearing minerals were analyzed using reflectance spectroscopy in the long-wave ultraviolet, visible, near-infrared, and mid-infrared regions (0.35-8 μm) in order to identify spectral features characteristic of the NH4+ molecule, and to evaluate if and how these features vary among different species. Mineral phases were confirmed through structural and compositional analyses using X-ray diffraction, X-ray fluorescence, and elemental combustion analysis. Characteristic absorption features associated with NH4 can be seen in the reflectance spectra at wavelengths as short as ∼1 μm. In the near-infrared region, the most prominent absorption bands are located near 1.6, 2.0, and 2.2 μm. Absorption features characteristic of NH4+ occurred at slightly longer wavelengths in the mineral-bound NH4+ spectra than for free NH4+ for most of the samples. Differences in wavelength position are attributable to various factors, including differences in the type and polarizability of the anion(s) attached to the NH4+, degree and type of hydrogen bonding, molecule symmetry, and cation substitutions. Multiple absorption features, usually three absorption bands, in the mid-infrared region between ∼2.8 and 3.8 μm were seen in all but the most NH4-poor sample spectra, and are attributed to fundamentals, combinations, and overtones of stretching and bending vibrations of the NH4+ molecule. These features appear even in reflectance spectra of water-rich samples which exhibit a strong 3 μm region water absorption feature. While many of the samples examined in this study have NH4 absorption bands

  8. Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Multisensor Analyzed Sea Ice Extent Northern Hemisphere (MASIE-NH) products provide measurements of daily sea ice extent and sea ice edge boundary for the...

  9. On the volatility of nihonium (Nh, Z = 113)

    Energy Technology Data Exchange (ETDEWEB)

    Aksenov, Nikolay V.; Steinegger, Patrick; Abdullin, Farid Sh.; Albin, Yury V.; Chepigin, Viktor I.; Lebedev, Vyacheslav Ya.; Madumarov, Alexander Sh.; Malyshev, Oleg N.; Petrushkin, Oleg V.; Polyakov, Alexander N.; Popov, Yury A.; Sabel' nikov, Alexey V.; Sagaidak, Roman N.; Shirokovsky, Igor V.; Shumeiko, Maksim V.; Starodub, Gennadii Ya.; Tsyganov, Yury S.; Utyonkov, Vladimir K.; Voinov, Alexey A.; Vostokin, Grigory K.; Yeremin, Alexander V.; Dmitriev, Sergey N. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russian Federation); Bozhikov, Gospodin A. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Advanced Physical Studies, Sofia (Bulgaria); Eichler, Robert [Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen PSI (Switzerland); Departement fuer Chemie und Biochemie, Universitaet Bern, Bern (Switzerland)

    2017-07-15

    Gas-phase chromatography studies of nihonium (Nh, Z = 113) were carried out at the one-atom-at-a-time level. For the production of nihonium, the heavy-ion-induced nuclear fusion reaction of {sup 48}Ca with {sup 243}Am was used. This leads to isotopes {sup 284,285}Nh, as the direct descendants of the α-decaying precursors {sup 288,289}Mc. Combining the Dubna Gas-Filled Recoil Separator with gas-phase chromatographic separation, the experiment was sensitive to elemental nihonium and its adsorption behavior on Teflon, theoretically predicted by modern relativistic density functional theory. The non-observation of any decays of Nh after the chemical separation indicates a larger than expected retention of elemental Nh on a Teflon surface. (orig.)

  10. Heterogeneous OH initiated oxidation: a possible explanation for the persistence of organophosphate flame retardants in air.

    Science.gov (United States)

    Liu, Yongchun; Liggio, John; Harner, Tom; Jantunen, Liisa; Shoeib, Mahiba; Li, Shao-Meng

    2014-01-21

    Heterogeneous reactions between OH radicals and emerging flame retardant compounds coated on inert particles have been investigated. Organophosphate esters (OPEs) including triphenyl phosphate (TPhP), tris-2-ethylhexyl phosphate (TEHP), and tris-1,3-dichloro-2-propyl phosphate (TDCPP) were coated on (NH4)2SO4 particles and exposed to OH radicals in a photochemical flow tube at 298 K and (38.0 ± 2.0) % RH. The degradation of these particle-bound OPEs was observed as a result of OH exposure, as measured using a Time-of-Flight Aerosol Mass Spectrometer. The derived second-order rate constants for the heterogeneous loss of TPhP, TEHP, and TDCPP were (2.1 ± 0.19) × 10(-12), (2.7 ± 0.63) × 10(-12), and (9.2 ± 0.92) × 10(-13) cm(3) molecule(-1) s(-1), respectively, from which approximate atmospheric lifetimes are estimated to be 5.6 (5.2-6.0), 4.3 (3.5-5.6), and 13 (11-14) days. Additional coating of the OPE coated particles with an OH radical active species further increased the lifetimes of these OPEs. These results represent the first reported estimates of heterogeneous reaction rate constants for these species. The results demonstrate that particle bound OPEs are highly persistent in the atmosphere with regard to OH radical oxidation, consistent with the assumption that OPEs can undergo medium or long-range transport, as previously proposed on the basis of field measurements. Finally, these results indicate that future risk assessment and transport modeling of emerging priority chemicals with semi- to low-volatility must consider particle phase heterogeneous loss processes when evaluating environmental persistence.

  11. Lions and tigers and bears, oh my! children's conceptions of forests and their inhabitants

    Science.gov (United States)

    Strommen, Erik

    Forty first-grade children, drawn from urban areas in Nebraska and New Jersey, were asked to produce drawings of forests and were interviewed about forests and the types of living things found in them. Results indicate that the children's concepts of animals and where they live are quite diverse, but highly concrete and unorganized. Although children correctly assigned most forest-dwellers to the forest (deer and squirrels, for example), they also tended to assign almost all other animals (elephants, sharks, etc.) to the forest as well, especially carnivores. A general lack of awareness of plant life, insects, water resources, and other forest features was also observed.Received: 17 March 1994; Revised: 17 January 1995;

  12. NH AND Mg INDEX TRENDS IN ELLIPTICAL GALAXIES

    International Nuclear Information System (INIS)

    Serven, Jedidiah; Worthey, Guy; Toloba, Elisa; Sanchez-Blazquez, Patricia

    2011-01-01

    We examine the spectrum in the vicinity of the NH3360 index of Davidge and Clark, which was defined to measure the NH absorption around 3360 A and shows almost no trend with velocity dispersion, unlike other N-sensitive indices, which show a strong trend. Computing the effect of individual elements on the integrated spectrum with synthetic stellar population integrated spectra, we find that, while being well correlated with nitrogen abundance, NH3360 is almost equally well anti-correlated with Mg abundance. This prompts the definition of two new indices, Mg3334, which is mostly sensitive to magnesium, and NH3375, which is mostly sensitive to nitrogen. Rather surprisingly, we find that the new NH3375 index shows a trend versus optical absorption feature indices that is as shallow as the NH3360 index. We hypothesize that the lack of a strong index trend in these near-UV indices is due to the presence of an old metal-poor component of the galactic population. Comparison of observed index trends and those predicted by models shows that a modest fraction of an old, metal-poor stellar population could easily account for the observed flat trend in these near-UV indices while still allowing substantial N abundance increase in the larger galaxies.

  13. In vivo evaluation of the 3-carboranyl thymidine analogue (3-CTA), N5-2OH, for neutron capture therapy

    International Nuclear Information System (INIS)

    Barth, Rolf F.; Yang, Weilian; Wu, Gong; Byun, Youngjoo; Tjarks, Werner; Eriksson, Staffan; Binns, Peter J.; Riley, Kent J.

    2006-01-01

    The purpose of the present study was to evaluate a 3 CTA, designated N5-2OH, as a boron delivery agent for NCT. Target validation was established using the thymidine kinase 1 (+) wild type L929 cell line and its TK1(-) counterpart, which were implanted subcutaneously into NIH nu/nu mice. 10 B-enriched N5-2OH, solubilized in DMSO (50μg 10 B in 15μl), was administered by 2 intratumoral (i.t.) injections at 2 h intervals. Two hours later the animals were irradiated at the MITR-II Research Reactor, following which tumor volumes were determined over a period of 30 days. Mice bearing TK1(+) wild type tumors, which had received N5-2OH, had a 15 fold inhibition in tumor growth compared to TK1(-) controls (247 versus 3,603 mm 3 ). Based on these data, biodistribution and therapy studies were initiated in F98 glioma bearing rats. Animals received 500μg of N5-2OH, administered intracerebrally (i.c.) by convection enhanced delivery (CED) using ALZET pumps (8μl/h for 24 h). The tumor boron concentration was 17.3μg/g compared to undetectable amounts in normal brain and blood. BNCT was carried out 14 d following i.c. implantation of 10 3 F98 glioma cells and 24 h following CED of N5-2OH (500μg/200μl). The mean survival time (MST) of these animals was 38 d compared to 31 d and 25 d, respectively, for irradiated and untreated controls. Studies are planned to optimize the delivery and formulation of N5-2OH and additional therapy studies will be carried out using N5-2OH in combination with BPA and BSH. (author)

  14. Compliant hydrodynamic fluid journal bearing

    Science.gov (United States)

    Warren, E. L. (Inventor)

    1985-01-01

    An air bearing structure is described that prevents destructive bending moments within the top foil. Welds are eliminated by mounting the top bearing foil in the bearing cartridge sleeve without using a space block. Tabs or pins at the end of the top bearing foil are restrained by slots or stops formed in the cartridge sleeve. These structural members are free to move in a direction normal to the shaft while being restrained from movement in the direction of shaft rotation.

  15. FRAIL-NH Predicts Outcomes in Long Term Care.

    Science.gov (United States)

    Kaehr, E W; Pape, L C; Malmstrom, T K; Morley, J E

    2016-02-01

    To investigate the predictive validity of the short, simple FRAIL-NH frailty screening tool in the long term care population and to then compare the predictive validity with the frailty index (FI) for 6-month adverse health outcomes. Retrospective study using the Minimum Data Set (MDS) 3.0 and chart review from June-December 2014. Two Long Term Care Facilities in Saint Louis, MO. 270 patients ages ≥ 65 years old residing in long term care. Frailty was measured using the FRAIL-NH and Frailty Index (FI) criteria. Adverse outcomes measured at 6-month follow-up included falls, hospitalizations, and hospice enrollment/mortality. Based on screening tool used frailty prevalence was 48.7% for FRAIL-NH and 30.3% for FI. The FRAIL-NH pre-frail (Adjusted Odds Ratio [AOR]=2.62; 95% Confidence Interval [CI]=1.25-5.54; p=0.11) classification was associated with 6 month risk of falling and mortality/hospice enrollment was associated with the frail classification, AOR=3.96 (1.44-10.87, p=0.007). Combining the pre-frail and frail categories both measures predicted 6 month mortality with the FRAIL-NH being the strongest predictor (AOR=3.36; 95%CI=1.26-8.98; p=0.016) and the FI was a more modest predictor with an AOR of 2.28; 95%CI=1.01-5.15; p=0.047. When directly comparing the FRAIL-NH to the FI, the FRAIL-NH pre-frail were at increased risk of falling, AOR=2.42 (1.11-5.92, p=0.027) and the FRAIL-NH frail were at increased risk of hospice enrollment/death, OR=3.25 (1.04- 10.86) p=0.044. In comparison to the FI, the FRAIL-NH preformed just as well at screening for frailty and was a slightly better predictor of adverse outcomes. The FRAIL-NH is a brief, easy-to-administer frailty screening tool appropriate for long term care patients and predicts increased risk of falls in the pre-frail and mortality/hospice enrollment in the frail.

  16. 13C, 18O, and D Fractionation Effects in the Reactions of CH3OH Isotopologues with Cl andOH Radicals

    DEFF Research Database (Denmark)

    Feilberg, Karen; Gruber-Stadler, Margaret; Johnson, Matthew Stanley

    2008-01-01

    with measured high-resolution infrared spectra as references. The relative reaction rates defined as R ) klight/kheavy are determined to be: kOH + CH3OH/kOH + 13CH3OH ) 1.031 ( 0.020, kOH + CH3OH/kOH + CH3 18OH ) 1.017 ( 0.012, kOH + CH3OH/kOH + CH2DOH ) 1.119 ( 0.045, kOH + CH3OH/kOH + CHD2OH ) 1.326 ( 0.......021 and kOH + CH3OH/kOH + CD3OH ) 2.566 ( 0.042, kCl + CH3OH/kCl + 13CH3OH ) 1.055 ( 0.016, kCl + CH3OH/ kCl + CH3 18OH ) 1.025 ( 0.022, kCl + CH3OH/kCl + CH2DOH ) 1.162 ( 0.022 and kCl + CH3OH/kCl + CHD2OH ) 1.536 ( 0.060, and kCl + CH3OH/kCl + CD3OH ) 3.011 ( 0.059. The errors represent 2s from...

  17. Magnetic bearing and motor

    Science.gov (United States)

    Studer, Philip A. (Inventor)

    1983-01-01

    A magnetic bearing assembly (10) has an intermediate rotatable section (33) having an outer cylindrical member (30) coaxially suspended by a torsion wire (72) around an axially polarized cylindrical magnet (32). Axial alignment between the pole faces (40-43) of the intermediate section (33) and end surfaces (50-53) of opposed end bells (20, 22) provides a path of least reluctance across intervening air gaps (60-63) for the magnetic flux emanating from magnet (32). Radial dislocation increases the reluctance and creates a radial restoring force. Substitution of radially polarized magnets 107 fixed to a magnetically permeable cylinder (32') and insertion of pairs of armature coil windings (109-112) between the cylinder pair (33') provides an integral magnetic bearing and torsion motor (100) able to provide arcuately limited rotational drive.

  18. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  19. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  20. COMPOSITION OF BLACK BEAR MILK.

    Science.gov (United States)

    An analysis of black bear ( Ursus americanus Pallas) milk showed that the total solids, fat and protein were much higher and the lactose lower than...either cow or human milk. In comparison with polar bear (Thalarcotos maritimus ), the black bear milk was lower in fat, protein and total calories. (Author)

  1. Frictionless Bearing Uses Permanent Magnets

    Science.gov (United States)

    1965-01-01

    The purpose of this innovation was to develop a frictionless bearing for high speed, light load applications. The device involves the incorporation of permanent magnets in the bearing design. The repulsion of like magnetic poles provides concentric support of the inner member so that no metallic contact occurs between the bearing surfaces.

  2. Rotating plug bearing and seal

    International Nuclear Information System (INIS)

    Wade, E.E.

    1977-01-01

    Disclosed is a bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing. 19 claims, 3 figures

  3. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  4. Reflection of OH molecules from magnetic mirrors

    NARCIS (Netherlands)

    Metsaelae, Markus; Gilijamse, Joop J.; Hoekstra, Steven; van de Meerakker, Sebastiaan Y. T.; Meijer, Gerard

    2008-01-01

    We have reflected a Stark-decelerated beam of OH molecules under normal incidence from mirrors consisting of permanent magnets. Two different types of magnetic mirrors have been demonstrated. A long-range flat mirror made from a large disc magnet has been used to spatially focus the reflected beam

  5. Photodissociation of OH in interstellar clouds

    NARCIS (Netherlands)

    Dishoeck, van E.F.; Dalgarno, A.

    1984-01-01

    Calculations are presented of the lifetime of OH against photodissociation by the interstellar radiation field as a function of depth into interstellar clouds containing grains of various scattering properties. The effectiveness of the different photodissociation channels changes with depth into a

  6. Effect of Chemical Treatment of Sesame Stover with NaOH and Urea on Chemical Composition and In vivo Rumen Digestion in Sheep

    Directory of Open Access Journals (Sweden)

    Mohammad MALEKKHAHI

    2014-03-01

    Full Text Available This study tested the effect of urea, urea sodium hydroxide (NaOH and NaOH + urea on chemical composition and total tract nutrition in sheep. Treated stovers were prepared by mixing stovers with aqueous solution of urea (SU, 3g in 100 ml water /100 g DM, NaOH (SN, 4g in 100 ml water /100g DM and urea + NaOH (SUN. Five male Balouchi sheep (30 ±1.4 kg were used in a change-over design. In vivo experimental diets were as follows: alfalfa hay (AH, alfalfa hay + S (AHS, alfalfa hay + SU (AH SU, alfalfa hay + SN (AHSN and alfalfa hay + SUN (AHSUN. The NDF content significantly (P0.05 in urea and NaOH. The urea caused a significant (P<0.05 increase in CP content of sesame stover. The digestibility coefficients of DM, OM, NDF and ADF increased with chemically treatment of sesame stover. Furthermore, rumen pH was not affected by the chemical treatment, while rumen NH3- N (P<0.05 concentration was enhanced by urea +NaOH treatment. These results suggest that digestibility of DM, OM, CP, NDF and ADF could be improved by chemical treatment with urea and NaOH.

  7. 24,25(OH)2D3 enhances the calcemic effect of 1,25(OH)2D3.

    Science.gov (United States)

    Wald, H; Hayek, T; Popovtzer, M M

    1985-11-01

    The effect of 24,25(OH)2D3 on 1,25(OH)2D3-induced hypercalcemia was studied in normal rats. Serum (S) levels and urinary excretion of Ca2+ (UCaV) were measured in (a) control rats, (b) rats receiving a daily sc injection of 54 ng 1,25(OH)2D3, (c) rats receiving 24,25(OH)2D3 in the same dose and same manner, and (d) rats receiving 1,25(OH)2D3 + 24,25(OH)2D3. The animals were housed in metabolic cages and 24-hr urine specimens were collected. After 24 hr SCa2+ increased similarly with 1,25(OH)2D3 and with 1,25(OH)2D3 + 24,25(OH)2D3, while 24,25(OH)2D3 alone did not change SCa2+. UCaV after 24 hr increased significantly less (P less than 0.025) with 1,25(OH)2D3 + 24,25(OH)2D3 than with 1,25(OH)2D3 alone. After 5 days of 1,25(OH)2D3, SCa2+ rose from 5.1 +/- 0.15 to 6.29 +/- 0.08 whereas 1,25(OH)2D3 + 24,25(OH)2D3 effected a greater increase in SCa2+ up to 6.63 +/- 0.09 (P less than 0.01). 24,25(OH)2D3 alone did not change SCa2+. UCaV after 5 days of treatment rose similarly with 1,25(OH)2D3 and with 1,25(OH)2D3 + 24,25(OH)2D3. After 10 days of 1,25(OH)2D3 SCa2+ was 6.17 +/- 0.15 meq/liter while with the combination SCa2+ rose to 6.74 +/- 0.2 (P less than 0.025). 24,25(OH)2D3 alone did not change SCa2+. These results show that (a) 24,25(OH)2D3 alone does not alter SCa2+ in normal rats, (b) combined administration of 1,25(OH)2D3 + 24,25(OH)2D3 enhances the hypercalcemic response to 1,25(OH)2D3 without a parallel increase in UCaV, and (c) it is suggested that the effect of 24,25(OH)2D3 on serum Ca2+ level, at least partly, may result from its hypocalciuric effect.

  8. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  9. Bearing, gearing, and lubrication technology

    Science.gov (United States)

    Anderson, W. J.

    1978-01-01

    Results of selected NASA research programs on rolling-element and fluid-film bearings, gears, and elastohydrodynamic lubrication are reported. Advances in rolling-element bearing material technology, which have resulted in a significant improvement in fatigue life, and which make possible new applications for rolling bearings, are discussed. Research on whirl-resistant, fluid-film bearings, suitable for very high-speed applications, is discussed. An improved method for predicting gear pitting life is reported. An improved formula for calculating the thickness of elastohydrodynamic films (the existence of which help to define the operating regime of concentrated contact mechanisms such as bearings, gears, and cams) is described.

  10. Hydrothermal crystal growth and structure determination of double hydroxides LiSb(OH)₆, BaSn(OH)₆, and SrSn(OH)₆.

    Science.gov (United States)

    Mizoguchi, Hiroshi; Bhuvanesh, Nattamai S P; Kim, Young-Il; Ohara, Satoshi; Woodward, Patrick M

    2014-10-06

    Colorless single crystals of LiSb(OH)6, SrSn(OH)6, and BaSn(OH)6, which are useful as precursors for the synthesis of LiSbO3, SrSnO3, and BaSnO3, were synthesized by a low-temperature hydrothermal method using a Teflon-lined autoclave at 380 K. The crystal structures were determined by single-crystal X-ray diffraction measurements. LiSb(OH)6 crystallizes in the trigonal space group P3̅1m with a = 5.3812(3)A, c = 9.8195(7)A, V = 246.25(3)A(3), Z = 2. In this layered structure, [Li2Sb(OH)6](+) and [Sb(OH)6](-) layers are alternately stacked along the c-direction. The [Li2Sb(OH)6](+) layer can be regarded as a cation-ordered CdCl2 layer. The [Sb(OH)6)](-) layer is built up from isolated [Sb(OH)6](-) octahedra, which are linked to each other via hydrogen bonding within the layer. BaSn(OH)6 and SrSn(OH)6 crystallize with monoclinic P21/n space group symmetry. The monoclinic structure possesses a CsCl-type packing of Ba(2+)/Sr(2+) cations and [Sn(OH)6](2-) anions. The [Sn(OH)6](2-) polyhedra are connected to each other through hydrogen bonding to form a three-dimensional framework. The factors that favor these hitherto unknown crystal structures are discussed using a structure map that compares various M(OH)3 and M'M″(OH)6 compounds.

  11. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  12. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  13. Cation incorporation into zirconium oxide in LiOH, NaOH, and KOH solutions

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, K.H.; Baek, J.H.

    1999-01-01

    To investigate the cation incorporation into zirconium oxide, SIMS analysis was performed on the specimens prepared to have an equal oxide thickness in LiOH, NaOH, and KOH solutions. Even though they have an equal oxide thickness in LiOH, NaOH, and KOH solutions, the penetration depth of cation into the oxide decreased with an increase in the ionic radius of cation. The cation is considered to control the corrosion in alkali hydroxide solutions and its effect is dependent on the concentration of alkali and the oxide thickness. The slight enhancement of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide, while the significant acceleration at a high concentration is due to the transformation of oxide microstructures that would be also induced by cation incorporation into oxide. (orig.)

  14. Highly supersonic bipolar mass ejection from a red giant OH/IR source - OH 0739 - 14

    Science.gov (United States)

    Cohen, M.; Dopita, M. A.; Schwartz, R. D.; Tielens, A. G. G. M.

    1985-01-01

    From long-slit spectrophotometry of the bipolar nebula associated with the unusual OH source, OH 0739 - 14, the presence of a blue companion to the M9 III central star was shown and a Herbig-Haro-like knot beyond each nebular lobe was discovered. From differential colors of the lobes and from radial velocities of these knots it was demonstrated that the system inclines its northern lobe in the forward direction. It was also shown that the nebulous knots are shocks being driven into an extensive circumstellar envelope, and that this material is very overabundant in nitrogen, suggesting that it is matter lost from a star of mass greater than 3 solar masses. A model of biconical ejection from a central binary is consistent with the OH observations, and a possible relation of OH 0739 - 14 to the symbiotic stars and to bipolar planetary nebulae is suggested.

  15. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  16. Ternary Ni–Cu–OH and Ni–Co–OH electrodes for electrochemical energy storage

    KAUST Repository

    Alhebshi, Nuha

    2015-10-01

    In this project, Ni–Cu–OH and Ni–Co–OH ternary electrodes have been prepared. Different Ni:Cu and Ni:Co ratios were deposited by chemical bath deposition (CBD) at room temperature on carbon microfibers. Since Ni(OH)2 is notorious for poor cycling stability, the goal of the work was to determine if doping with Cu or Co could improve Ni(OH)2 cycling stability performance and conductivity against reaction with electrolyte. It is observed that the electrodes with Ni:Cu and Ni:Co composition ratio of 100:10 result in the optimum capacitance and cycling stability in both Ni–Cu–OH and Ni–Co–OH electrodes. This improvement in cycling stability can be attributed to the higher redox reversibility as indicated by the smaller CV redox peak separation. In addition, it is found that decreasing Cu and Co ratios, with fixed CBD time, enhances nanoflakes formation, and hence increases electrode capacitance. For the optimum composition (Ni:Co = 100:10), composites of the ternary electrodes with graphene and carbon nanofibers were also tested, with resultant improvement in potential window, equivalent series resistance, areal capacitance and cycling stability.

  17. A kinetic study of struvite precipitation recycling technology with NaOH/Mg(OH)2 addition.

    Science.gov (United States)

    Yu, Rongtai; Ren, Hongqiang; Wang, Yanru; Ding, Lili; Geng, Jingji; Xu, Ke; Zhang, Yan

    2013-09-01

    Struvite precipitation recycling technology is received wide attention in removal ammonium and phosphate out of wastewater. While past study focused on process efficiency, and less on kinetics. The kinetic study is essential for the design and optimization in the application of struvite precipitation recycling technology. The kinetics of struvite with NaOH/Mg(OH)2 addition were studied by thermogravimetry analysis with three rates (5, 10, 20 °C/min), using Friedman method and Ozawa-Flynn-Wall method, respectively. Degradation process of struvite with NaOH/Mg(OH)2 addition was three steps. The stripping of ammonia from struvite was mainly occurred at the first step. In the first step, the activation energy was about 70 kJ/mol, which has gradually declined as the reaction progress. By model fitting studies, the proper mechanism function for struvite decomposition process with NaOH/Mg(OH)2 addition was revealed. The mechanism function was f(α)=α(α)-(1-α)(n), a Prout-Tompkins nth order (Bna) model. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Wet Mechanochemical Processing of Celestine using (NH42CO3

    Directory of Open Access Journals (Sweden)

    Deniz Bingöl

    2017-06-01

    Full Text Available In this study, traditional (univariate method of processing to the wet mechanochemical treatment were applied to obtain both SrCO3 and (NH42SO4 from celestite (SrSO4-(NH42CO3-H2O mixtures in a planetary ball mill. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were used to analyze products formed during wet milling. A hydrometallurgical process was carried out to examine milling time, ball to grinding material mass ratio, (NH42CO3 to SrSO4 mole ratio and rotational speed of the mill in a planetary mill. Under optimum conditions, a conversion approaching 100% of SrCO3 was obtained.

  19. Electron transport in NH3/NO2 sensed buckled antimonene

    Science.gov (United States)

    Srivastava, Anurag; Khan, Md. Shahzad; Ahuja, Rajeev

    2018-04-01

    The structural and electronic properties of buckled antimonene have been analysed using density functional theory based ab-initio approach. Geometrical parameters in terms of bond length and bond angle are found close to the single ruffle mono-layer of rhombohedral antimony. Inter-frontier orbital analyses suggest localization of lone pair electrons at each atomic centre. Phonon dispersion along with high symmetry point of Brillouin zone does not signify any soft mode. With an electronic band gap of 1.8eV, the quasi-2D nano-surface has been further explored for NH3/NO2 molecules sensing and qualities of interaction between NH3/NO2 gas and antimonene scrutinized in terms of electronic charges transfer. A current-voltage characteristic has also been analysed, using Non Equilibrium Green's function (NEGF), for antimonene, in presence of incoming NH3/NO2 molecules.

  20. Phosphate recovery from anaerobic digester effluents using CaMg(OH)4.

    Science.gov (United States)

    Liu, Xueyu; Xu, Zhonghou; Peng, Jianfeng; Song, Yonghui; Meng, Xiaoguang

    2016-06-01

    Dolomite lime (DL) (CaMg(OH)4) was used as an economical source of Mg(2+) for the removal and recovery of phosphate from an anaerobic digester effluent of a municipal wastewater treatment plant (MWWTP) wastewater. Batch precipitation results determined that phosphate was effectively reduced from 87 to less than 4mg-P/L when the effluent water was mixed with 0.3g/L of DL. The competitive precipitation mechanisms of different solids in the treatment system consisting of Ca(2+)-Mg(2+)-NH4(+)-PO4(3-)CO3(2-) were determined by comparing model predictions with experimental results. Thermodynamic model calculations indicated that hydroxyapatite (Ca10(PO4)6(OH)2), Ca4H(PO4)3∙3H2O, Ca3(PO4)2(beta), and Ca3(PO4)2(am2) were more stable than struvite (MgNH4PO3∙6H2O) and calcite (CaCO3). However, X-ray diffraction (XRD) analysis determined the formation of struvite and calcite minerals in the treated effluent. Kinetic experimental results showed that most of the phosphate was removed from synthetic effluent containing NH4(+) within 2hr, while only 20% of the PO4(3-) was removed in the absence of NH4(+) after 24hr of treatment. The formation of struvite in the DL-treated effluent was due to the rapid precipitation rate of the mineral. The final pH of the DL-treated effluent significantly influenced the mass ratio of struvite to calcite in the precipitates. Because more calcite was formed when the pH increased from 8.4 to 9.6, a pH range of 8.0-8.5 should be used to produce solid with high PO4(3-) content. This study demonstrated that DL could be used for effective removal of phosphate from the effluent and that resultant precipitates contained high content of phosphate and ammonium. Copyright © 2016. Published by Elsevier B.V.

  1. First detection of ammonia (NH3) in the upper troposphere

    Science.gov (United States)

    Höpfner, Michael; Volkamer, Rainer; Grabowski, Udo; Grutter de la Mora, Michel; Orphal, Johannes; Stiller, Gabriele; von Clarmann, Thomas

    2016-04-01

    Ammonia (NH3) is the major alkaline trace gas in the troposphere. Neutralization of atmospheric acids, like HNO3 and H2SO4, leads to formation of ammonium nitrate and ammonium sulfate aerosols. Further, there are indications that NH3 may enhance nucleation of sulfuric acid aerosols by stabilization of sulfuric acid clusters. By far the largest source of ammonia is agricultural food production. Major global emissions are located in S-E Asia as e.g. shown by satellite nadir observations. Besides its importance with respect to air quality issues, an increase of ammonia emissions in the 21st century might lead to a significant climate radiative impact through aerosol formation. In spite of its significance, there is a lack of observational information on the global distribution of NH3 in the mid- and upper troposphere. Observational evidence, however, would be important for testing e.g. model results on the fate of ammonia from its source regions on ground to altitudes up to the tropopause. In this contribution we will show, to our knowledge, the first unequivocal detection of ammonia in the upper troposphere. This result has been achieved through analysis of infrared limb-emission observations performed with the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument on board the Envisat satellite from 2002-2012. On a global scale, enhanced values of ammonia have been measured in the upper tropospheric region influenced by the Asian monsoon. We will present a quantitative analysis of the retrieved concentrations of NH3 including an error assessment and further retrieval diagnostics. The results will be discussed with respect to the variability of NH3 locally within the Asian monsoon region's upper troposphere and at different years. Further, we will show comparisons between global distributions of NH3 from published model simulations and our observational dataset from MIPAS.

  2. Formulation of an inhibitor radiopharmaceutical of prostatic antigen of {sup 177}Lu-Glu-Nh-CO-Nh-Lys membrane; Formulacion de un radiofarmaco inhibidor del antigeno prostatico de membrana {sup 177}Lu-Glu-NH-CO-NH-Lys

    Energy Technology Data Exchange (ETDEWEB)

    Ortega S, D.

    2015-07-01

    The prostate specific membrane antigen (PSMA) is a zinc metalloenzyme that is expressed on the cell membrane and highly expressed in prostate cancer. Recently, it has been demonstrated that the peptide sequence Glu-Nh-CO-Nh-Lys inhibit PSMA activity through an electrostatic interaction with the Zn. Several theragnostic radiopharmaceuticals with base in {sup 177}Lu have been developed for radiotherapy of specific molecular targets because gamma and beta emissions of the radionuclide (β = 0.498 MeV and γ= 0.133 MeV). However, there is currently no label a formulation for preparing a radiopharmaceutical of {sup 177}Lu-Glu-Nh-CO-Nh-Lys useful treatment of prostate cancer. The aim of this research was to optimize and document the process of production of the radiopharmaceutical {sup 177}Lu-Glu-Nh-CO-Nh-Lys for sanitary registration application before the Comision Federal para la Proteccion contra Riesgos Sanitarios (COFEPRIS). The optimization of the production process was assessed a factorial design of three variables with mixed levels (3 x 3 x 2) where the dependent variable is the radiochemical purity, the analytical method was validated by UV-Vis spectrophotometry. Next, process validation was carried out by labeling 3 lots of the optimized formulation of the radiopharmaceutical (5.55 GBq (2.16 μg) of {sup 177}LuCl{sub 3}, 90 mg peptide PSMA, 50 mg ascorbic acid and 150 μL of acetate buffer 1 M ph 5), long-term stability was performed by high resolution liquid chromatography) to determine its useful shelf life. 3 validation batches were prepared under protocols of Good Manufacturing Practice (GMP) in the Production Plant of Radiopharmaceuticals of the Instituto Nacional de Investigaciones Nucleares (ININ), meet specifications preset by obtaining a sterile and free development of bacterial endotoxin yields of labeled 100% and which retains its quality characteristics radiochemical purity greater than 90% for at least 15 days. (Author)

  3. Improved GaSb surfaces using a (NH4)2S/(NH4)2S04 solution

    International Nuclear Information System (INIS)

    Murape, D.M.; Eassa, N.; Nyamhere, C.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

    2012-01-01

    Bulk (1 0 0) n-GaSb surfaces have been treated with a sulphur based solution ((NH 4 ) 2 S/(NH 4 ) 2 SO 4 ) to which sulphur has been added, not previously reported for the passivation of GaSb surfaces. Au/n-GaSb Schottky barrier diodes (SBDs) fabricated on the treated material show significant improvement compared to that of the similar SBDs on the as-received material as evidenced by the lower ideality factor (n), higher barrier height (φ b ) and lower contact resistance obtained. Additionally, the reverse leakage current, although not saturating, has been reduced by almost an order of magnitude at −0.2 V. The sample surfaces were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The native oxide, Sb–O, present on the as-received material is effectively removed on treating with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ]+S) and (NH 4 ) 2 S. Analysis of the as-received surface by XPS, prior to and after argon sputtering, suggests that the native oxide layer is ≤8.5 nm.

  4. Synthesis, characterization and flocculation activity of novel Fe(OH){sub 3}-polyacrylamide hybrid polymer

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huilong; Cui Jinyan [Department of Chemistry, Dalian University of Technology, Dalian 116023 (China); Jiang Wenfeng, E-mail: dlutjiangwf@yahoo.com.cn [Department of Chemistry, Dalian University of Technology, Dalian 116023 (China)

    2011-11-01

    Highlights: {yields} The preparation of a novel Fe(OH){sub 3}-PAM hybrid polymer flocculant is achieved via free radical solution polymerization. {yields} Flocculation of kaolin suspensions using this novel Fe(OH){sub 3}-PAM hybrid polymer flocculant is revealed in this study. {yields} The statistical model was first applied for calculating the thermodynamic parameters for the kaolin flocculating process. - Abstract: A novel Fe(OH){sub 3}-polyacrylamide inorganic-organic hybrid polymer (FHPAM) was synthesized via free radical solution polymerization initiated by a redox initiation system ((NH{sub 4}){sub 2}S{sub 2}O{sub 8}-NaHSO{sub 3}) in an aqueous medium. Reaction parameters influencing the intrinsic viscosity and the yield of the hybrid polymer, such as initiator concentration, monomer mass fraction, temperature and reaction time were investigated and optimized. The results show that the maximum intrinsic viscosity and up to 94% yields of the hybrid polymer can be achieved using initiator concentration of 0.3% with acrylamide monomer mass fraction of 20% under solution polymerization at 40 deg. C for 7 h. The physicochemical properties of this hybrid flocculant were characterized with TEM, FTIR spectra, TGA, and conductivity. It was found that a chemical bond exists between Fe(OH){sub 3} colloid and polyacrylamide chains in the FHPAM. The application of the hybrid polymer for the treatment of 2.5 g L{sup -1} kaolin suspension indicates that it had an excellent flocculation capacity and its flocculation efficiency was much better than that of commercial available polyacrylamide (PAM) and polymeric ferric sulfate (PFS). The optimal conditions for the flocculation treatment of kaolin suspension were the FHPAM dosage of 40 mg L{sup -1} at pH 7.0. The thermodynamic parameters for the flocculation process were calculated based on a statistical model. Interpretation of the results was given.

  5. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  6. Formulation of an inhibitor radiopharmaceutical of prostatic antigen of 177Lu-Glu-Nh-CO-Nh-Lys membrane

    International Nuclear Information System (INIS)

    Ortega S, D.

    2015-01-01

    The prostate specific membrane antigen (PSMA) is a zinc metalloenzyme that is expressed on the cell membrane and highly expressed in prostate cancer. Recently, it has been demonstrated that the peptide sequence Glu-Nh-CO-Nh-Lys inhibit PSMA activity through an electrostatic interaction with the Zn. Several theragnostic radiopharmaceuticals with base in 177 Lu have been developed for radiotherapy of specific molecular targets because gamma and beta emissions of the radionuclide (β = 0.498 MeV and γ= 0.133 MeV). However, there is currently no label a formulation for preparing a radiopharmaceutical of 177 Lu-Glu-Nh-CO-Nh-Lys useful treatment of prostate cancer. The aim of this research was to optimize and document the process of production of the radiopharmaceutical 177 Lu-Glu-Nh-CO-Nh-Lys for sanitary registration application before the Comision Federal para la Proteccion contra Riesgos Sanitarios (COFEPRIS). The optimization of the production process was assessed a factorial design of three variables with mixed levels (3 x 3 x 2) where the dependent variable is the radiochemical purity, the analytical method was validated by UV-Vis spectrophotometry. Next, process validation was carried out by labeling 3 lots of the optimized formulation of the radiopharmaceutical (5.55 GBq (2.16 μg) of 177 LuCl 3 , 90 mg peptide PSMA, 50 mg ascorbic acid and 150 μL of acetate buffer 1 M ph 5), long-term stability was performed by high resolution liquid chromatography) to determine its useful shelf life. 3 validation batches were prepared under protocols of Good Manufacturing Practice (GMP) in the Production Plant of Radiopharmaceuticals of the Instituto Nacional de Investigaciones Nucleares (ININ), meet specifications preset by obtaining a sterile and free development of bacterial endotoxin yields of labeled 100% and which retains its quality characteristics radiochemical purity greater than 90% for at least 15 days. (Author)

  7. Tissue-specific congener composition of organohalogen and metabolite contaminants in East Greenland polar bears (Ursus maritimus).

    Science.gov (United States)

    Gebbink, Wouter A; Sonne, Christian; Dietz, Rune; Kirkegaard, Maja; Riget, Frank F; Born, Erik W; Muir, Derek C G; Letcher, Robert J

    2008-04-01

    Congener patterns of the major organohalogen contaminant classes of PCBs, PBDEs and their metabolites and/or by-products (OH-PCBs, MeSO2-PCBs, OH-PBDEs and MeO-PBDEs) were examined in adipose tissue, liver, brain and blood of East Greenland polar bears (Ursus maritimus). PCB, OH-PCB, MeSO2-PCB and PBDE congener patterns showed significant differences (pOH-PBDEs and MeO-PBDEs were not detected in the brain and liver, but had different patterns in blood versus the adipose tissue. Novel OH-polybrominated biphenyls (OH-PBBs), one tri- and two tetra-brominated OH-PBBs were detected in all tissues and blood. Congener pattern differences among tissues and blood are likely due to a combination of factors, e.g., biotransformation and retention in the liver, retention in the blood and blood-brain barrier transport. Our findings suggest that different congener pattern exposures to these classes of contaminants should be considered with respect to potential target tissue-specific effects in East Greenland polar bears.

  8. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  9. Improvement of bearing support lubrication

    Directory of Open Access Journals (Sweden)

    Shehovtseva E. V.

    2016-12-01

    Full Text Available Gas turbine engine bearing supports is an important part in providing product efficiency of general and special-purpose engineering industry. Attempts are being made to increase efficiency of bearing support. Such attempts are caused by the modern tendency of the development of engineering striving for compact machines and units possessing increased reliability and durability. Researches on finding discrepancies in operation of support for this purpose have been executed. The reasons of occurrence the fatigue crumbling on external bearing races at different stages development of working surface damage have been investigated. The basic constructions of support of shaft for the aviation gas turbine engine and methods of their lubrication have been considered. Shortcomings of existing methods of lubrication of bearing supports have been marked. The upgraded construction of the module of gas turbine bearing shaft, which allows to improve conditions of lubrication and bearing cooling as a result of a uniform oil feed to the contact zones of outside bearing race and rolling elements and forced oil removal from contact zones of inside bearing race and rolling elements has been suggested. The task of improving conditions of lubrication supply to an internal holder of the bearing has been solved. The developed design allows applying unconventional methods of lubrication and cooling of a bearing support. Thus it is recommended to use process of regulation of a microrough on working surfaces bearing support during grinding-in. It will allow to improve a stage grinding-in and to increase reliability and durability of bearing support.

  10. Synthesis and crystal structure of 4-fluorobenzylammonium dihydrogen phosphate, [FC6H4CH2NH3]H2PO4

    Directory of Open Access Journals (Sweden)

    Ali Rayes

    2016-12-01

    Full Text Available The asymmetric unit of the title salt, [p-FC6H4CH2NH3]+·H2PO4−, contains one 4-fluorobenzylammonium cation and one dihydrogen phosphate anion. In the crystal, the H2PO4− anions are linked by O—H...O hydrogen bonds to build corrugated layers extending parallel to the ab plane. The FC6H4CH2NH3+ cations lie between these anionic layers to maximize the electrostatic interactions and are linked to the H2PO4− anions through N—H...O hydrogen bonds, forming a three-dimensional supramolecular network. Two hydrogen atoms belonging to the dihydrogen phosphate anion are statistically occupied due to disorder along the OH...HO direction.

  11. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  12. Phosphorylation of 5-substituted NH-tetrazoles with dimethyl chloroacetylenephosphonate

    Czech Academy of Sciences Publication Activity Database

    Iakobson, George; Erkhitueva, E. B.; Svintsitskaya, N. I.

    2015-01-01

    Roč. 85, č. 9 (2015), s. 2219-2221 ISSN 1070-3632 Institutional support: RVO:61388963 Keywords : NH-tetrazoles * chloroacetylenephosphonate * tetrazole-containing vinylphosphonates * nucleophilic addition Subject RIV: CC - Organic Chemistry Impact factor: 0.481, year: 2015

  13. Reinforcing graphene oxide/cement composite with NH2 ...

    Indian Academy of Sciences (India)

    Abstract. In this study, pure and NH2-functionalized graphene oxide (GO) nanosheets have been added to the cement mortar with different weight percents (0.05, 0.10, 0.15, 0.20 and 0.25 wt%). In addition, the effects of func- tionalizing GO on the microstructure and mechanical properties (flexural/compressive strengths) of ...

  14. Silicates with incorporation of NH4+, Rb+, or Cs+

    NARCIS (Netherlands)

    Voncken, J.H.L.

    1990-01-01

    This thesis presents results of an experimental study on the incorporation of NH4+, Rb +, and Cs + in micas and feldspars. The studied micas are dioctahedral. The feldspars are sanidine-like. In chapter II it is shown that the ammonium analogue of muscovite, called tobelite, with the formula

  15. Reinforcing graphene oxide/cement composite with NH2 ...

    Indian Academy of Sciences (India)

    In this study, pure and NH 2 -functionalized graphene oxide (GO) nanosheets have been added to the cement mortar with different weight percents (0.05, 0.10, 0.15, 0.20 and 0.25 wt%). In addition, the effects of functionalizing GO on the microstructure and mechanical properties (flexural/compressive strengths) of cement ...

  16. Synthesis of Al(OH3 Nanostructures from Al(OH3 Microagglomerates via Dissolution-Precipitation Route

    Directory of Open Access Journals (Sweden)

    Bo Yu

    2013-01-01

    Full Text Available A facile method was developed to synthesize Al(OH3 nanostructures from Al(OH3 microagglomerates by dissolution in 9.0 mol·L−1 NaOH at 115°C followed by dilution and aging of the solution at room temperature. The influence of Al(OH3 nanoseed and surfactants as sodium dodecyl sulfate (SDS, polyethylene glycol 6000 (PEG6000, and cetyltrimethylammonium bromide (CTAB on the formation of the Al(OH3 nano-structures was investigated. The experimental results indicated that the Al(OH3 microspheres composed of nanoparticles were prepared in the blank experiment, while dispersive Al(OH3 nano-particles with a diameter of 80–100 nm were produced in the presence of Al(OH3 nano-seed and CTAB.

  17. Spectroscopic parameters of the low-lying electronic states and laser cooling feasibility of NH+cation and NH-anion.

    Science.gov (United States)

    Zhang, Qing-Qing; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Liu, Wen-Wang

    2017-10-05

    The potential energy curves and transition dipole moments of 1 2 Σ + , 2 2 Σ + , 1 2 Π and 2 2 Π states of NH + cation and NH - anion are calculated by using multi-reference configuration interaction method and large all-electron basis sets. Based on the obtained potential energy curves, the rotational and vibrational energy levels of the states are obtained by solving the Schrödinger equation of nuclear movement. The calculated spectroscopic parameters for NH + cation and NH - anion are in good agreement with available theoretical and experimental results. The spin orbit coupling effect of the 2 Π states for both NH + cation and NH - anion are calculated. The feasibility of laser cooling of the two molecules is examined by using the results of the molecular structure and spectroscopy. The highly diagonal Franck-Condon factors for the 1 2 Π (v″=0)↔1 2 Σ + (v'=0) transition of NH + and NH - are 0.821 and 0.999, while the radiative lifetimes of the 1 2 Σ + (v'=0) state for the two molecules are 384ns and 52.4ns, respectively. The results indicate that NH + cation and NH - anion are good candidate molecules for laser cooling. The cooling scheme via Sisyphus process for the NH + cation and NH - anion are proposed in the paper. The laser wavelengths for the close cycles of the absorption and radiation are also determined. Unfortunately, the potential energy curve of the ground state of the neutral NH molecule shows that the auto-detachment of NH - anion is possible, implying the optical scheme of laser cooling for NH - anion is not easy to achieve in the experiment although it has larger Franck-Condon factor. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. The combination of 1α, 25(OH)2 – Vitamin D3, calcium and acetylsalicyclic acid affects azoxymethane-induced aberrant crypt foci and colorectal tumours in rats

    DEFF Research Database (Denmark)

    Mølck, Anne-Marie; Poulsen, Morten; Meyer, Otto A.

    2002-01-01

    Effects of 1alpha,25(OH)(2)-vitamin D(3) and acetylsalicylic acid at various dietary levels of calcium (CaCO(3)) on development of aberrant crypt foci (ACF) and tumours in colon were examined in groups of 16 male F344 rats initiated with azoxymethane and observed for 16 weeks. Calcium was the most...... potent modulator of ACF development. The total number of ACF increased with low calcium and decreased with high calcium. The number of large ACF decreased with any addition of calcium, acetylsalicylic acid and 1alpha,25(OH)(2)-vitamin D(3). High levels of calcium alone or in combination with 1alpha,25(OH......)(2)-vitamin D(3) increased the incidence of tumour-bearing animals. 1alpha,25(OH)(2)-vitamin D(3) and acetylsalicylic acid at 5,000 ppm calcium increased the incidence as well....

  19. Autosizing Control Panel for Needle Bearing

    OpenAIRE

    Prof.A.R.Wadhekar,; Ms Jyoti R. Rajput

    2016-01-01

    A needle roller bearing is a bearing which uses small cylindrical rollers. Bearings are used to reduce friction of any rotating surface. Needle bearings have a large surface in contact with the bearing outer surfaces as compared to ball bearings. There is less added clearance(Diameter of the shaft and the diameter of the bearing are different) so they are much compact. The structure consists of a needle cage which contains the needle rollersthemselves and an outer race (The housin...

  20. Synthesis of quinoxaline derivatives via condensation of aryl-1,2-diamines with 1,2-diketones using (NH4)6 Mo7 O24 . 4 H2 O as an efficient, mild and reusable catalyst

    International Nuclear Information System (INIS)

    Hasaninejad, A.; Zare, A.; Mohammadizadeh, M. R.; Karami, Z.

    2009-01-01

    Ammonium heptamolybdate tetrahydrate [(NH 4 ) 6 Mo 7 O 24. 4H 2 O] efficiently catalyzes the condensation of aryl-1,2-diamines with l,2-diketones in EtOH/H 2 O as a green media at room temperature to afford quinoxaline derivatives as biologically interesting compounds. Ease of recycling of the catalyst is one of the most advantages of the proposed method

  1. The effect of Si and Al concentrations on the removal of U(VI) in the alkaline conditions created by NH3 gas

    Energy Technology Data Exchange (ETDEWEB)

    Katsenovich, Yelena P.; Cardona, Claudia; Lapierre, Robert; Szecsody, Jim; Lagos, Leonel E.

    2016-10-01

    Remediation of uranium in the deep unsaturated zone is a challenging task, especially in the presence of oxygenated, high-carbonate alkalinity soil and pore water composition typical for arid and semi-arid environments of the western regions of the U.S. This study evaluates the effect of various pore water constituencies on changes of uranium concentrations in alkaline conditions, created in the presence of reactive gases such as NH3 to effectively mitigate uranium contamination in the vadose zone sediments. This contaminant is a potential source for groundwater pollution through slow infiltration of soluble and highly mobile uranium species towards the water table. The objective of this research was to evaluate uranium sequestration efficiencies in the alkaline synthetic pore water solutions prepared in a broad range of Si, Al, and bicarbonate concentrations typically present in field systems of the western U.S. regions and identify solid uranium-bearing phases that result from ammonia gas treatment. In previous studies (Szecsody et al. 2012; Zhong et al. 2015), although uranium mobility was greatly decreased, solid phases could not be identified at the low uranium concentrations in field-contaminated sediments. The chemical composition of the synthetic pore water used in the experiments varied for silica (5–250 mM), Al3+ (2.8 or 5 mM), HCO3- (0–100 mM) and U(VI) (0.0021–0.0084 mM) in the solution mixture. Experiment results suggested that solutions with Si concentrations higher than 50 mM exhibited greater removal efficiencies of U(VI). Solutions with higher concentrations of bicarbonate also exhibited greater removal efficiencies for Si, Al, and U(VI). Overall, the silica polymerization reaction leading to the formation of Si gel correlated with the removal of U(VI), Si, and Al from the solution. If no Si polymerization was observed, there was no U removal from the supernatant solution. Speciation modeling indicated that the dominant uranium species in the

  2. The effect of Si and Al concentrations on the removal of U(VI) in the alkaline conditions created by NH3 gas

    International Nuclear Information System (INIS)

    Katsenovich, Yelena P.; Cardona, Claudia; Lapierre, Robert; Szecsody, Jim; Lagos, Leonel E.

    2016-01-01

    Remediation of uranium in the deep unsaturated zone is a challenging task, especially in the presence of oxygenated, high-carbonate alkalinity soil and pore water composition typical for arid and semi-arid environments of the western regions of the U.S. This study evaluates the effect of various pore water constituencies on changes of uranium concentrations in alkaline conditions, created in the presence of reactive gases such as NH 3 to effectively mitigate uranium contamination in the vadose zone sediments. This contaminant is a potential source for groundwater pollution through slow infiltration of soluble and highly mobile uranium species towards the water table. The objective of this research was to evaluate uranium sequestration efficiencies in the alkaline synthetic pore water solutions prepared in a broad range of Si, Al, and bicarbonate concentrations typically present in field systems of the western U.S. regions and identify solid uranium-bearing phases that result from ammonia gas treatment. In previous studies (Szecsody et al. 2012; Zhong et al. 2015), although uranium mobility was greatly decreased, solid phases could not be identified at the low uranium concentrations in field-contaminated sediments. The chemical composition of the synthetic pore water used in the experiments varied for silica (5–250 mM), Al 3+ (2.8 or 5 mM), HCO 3 − (0–100 mM) and U(VI) (0.0021–0.0084 mM) in the solution mixture. Experiment results suggested that solutions with Si concentrations higher than 50 mM exhibited greater removal efficiencies of U(VI). Solutions with higher concentrations of bicarbonate also exhibited greater removal efficiencies for Si, Al, and U(VI). Overall, the silica polymerization reaction leading to the formation of Si gel correlated with the removal of U(VI), Si, and Al from the solution. If no Si polymerization was observed, there was no U removal from the supernatant solution. Speciation modeling indicated that the dominant uranium

  3. EXOTIC METAL MOLECULES IN OXYGEN-RICH ENVELOPES: DETECTION OF AlOH (X1Σ+) IN VY CANIS MAJORIS

    International Nuclear Information System (INIS)

    Tenenbaum, E. D.; Ziurys, L. M.

    2010-01-01

    A new interstellar molecule, AlOH, has been detected toward the envelope of VY Canis Majoris (VY CMa), an oxygen-rich red supergiant. Three rotational transitions of AlOH were observed using the facilities of the Arizona Radio Observatory (ARO). The J = 9 → 8 and J = 7 → 6 lines at 1 mm were measured with the ARO Submillimeter Telescope, while the J = 5 → 4 transition at 2 mm was observed with the ARO 12 m antenna on Kitt Peak. The AlOH spectra exhibit quite narrow line widths of 16-23 km s -1 , as found for NaCl in this source, indicating that the emission arises from within the dust acceleration zone of the central circumstellar outflow. From a radiative transfer analysis, the abundance of AlOH relative to H 2 was found to be ∼1 x 10 -7 for a source size of 0.26'' or 22 R * . In contrast, AlCl was not detected with f ≤ 5 x 10 -8 . AlOH is likely formed just beyond the photosphere via thermodynamic equilibrium chemistry and then disappears due to dust condensation. The AlOH/AlO abundance ratio found in VY CMa is ∼17. Therefore, AlOH appears to be the dominant gas-phase molecular carrier of aluminum in this oxygen-rich shell. Local thermodynamic equilibrium calculations predict that the monohydroxides should be the major carriers of Al, Ca, and Mg in O-rich envelopes, as opposed to the oxides or halides. The apparent predominance of aluminum-bearing molecules in VY CMa may reflect proton addition processes in H-shell burning.

  4. Permanent-Magnet Meissner Bearing

    Science.gov (United States)

    Robertson, Glen A.

    1994-01-01

    Permanent-magnet meissner bearing features inherently stable, self-centering conical configuration. Bearing made stiffer or less stiff by selection of magnets, springs, and spring adjustments. Cylindrical permanent magnets with axial magnetization stacked coaxially on rotor with alternating polarity. Typically, rare-earth magnets used. Magnets machined and fitted together to form conical outer surface.

  5. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  6. What about the Javan Bear?

    NARCIS (Netherlands)

    Jentink, F.A.

    1898-01-01

    The other day I read in a dutch popular periodical a paper dealing with the different species of Bears and their geographical distribution. To my great surprise the Malayan Bear was mentioned from Java: the locality Java being quite new to me I wrote to the author of that paper and asked him some

  7. Elastic Constants of Brucite (Mg(OH)2) and Diaspore (AlO(OH)) to 12 GPa by Brillouin Scattering

    Science.gov (United States)

    Jiang, F.; Speziale, S.; Majzlan, J.; Duffy, T. S.

    2005-12-01

    Hydroxides such as brucite, Mg(OH)2, and diaspore, AlO(OH), serve as analogs for the more complex hydrogen-bearing minerals found in subduction zones. The single-crystal elastic constants of these two minerals were determined by Brillouin scattering up to 12 GPa in a diamond anvil cell. A 16:3:1 methanol-ethanol-water and 4:1 methanol-ethanol mixture were used as pressure media and ruby as pressure calibrant. Two platelets of brucite and three platelets of diaspore were measured at room pressure and over nine elevated pressures. Brillouin spectra were recorded in 37 directions with a 5-degree step for each plane. All individual elastic stiffness constants were retrieved by fitting the velocity data to the Christoffel's equation. The individual elastic constants, aggregate bulk and shear moduli, were then fitted to the finite Eulerian stain equations to obtain their pressure derivatives. For brucite, aggregate moduli and their pressure derivatives are KT0=35.9(9) GPa, GO=31.3(2) GPa, (∂ Kt/∂ P)T0=8.9(3), (∂ G/∂ P)O=4.33(4) for the Reuss bound. Diaspore aggregate moduli and their pressure derivatives are KT0=147.0(7) GPa, GO=114.8(5) GPa, (∂ Ks/∂ P)T0=4.1(1), (∂ G/∂ P)O=1.6(1). For diaspore, both individual and aggregate elastic moduli define nearly linear modulus pressure trend within the measured pressure range. For Brucite, there are clear deviations from linear modulus - pressure trends. In comparison with diaspore, brucite exhibits strong anisotropy. The ratio of the linear compressibility of brucite along the c and a axes decreased from 4.7 to 1.3 over the examined pressure range. The shear anisotropy (C66/C44) decreased from 2.6 at ambient condition to 1.3 with increase of pressure to 12 GPa. Compression curves constructed from our Brillouin data for both brucite and diaspore are in good agreement with previous x-ray diffraction data.

  8. Direct observation of OH production from the ozonolysis of olefins

    Science.gov (United States)

    Donahue, Neil M.; Kroll, Jesse H.; Anderson, James G.; Demerjian, Kenneth L.

    Ozone olefin reactions may be a significant source of OH in the urban atmosphere, but current evidence for OH production is indirect and contested. We report the first direct observation of OH radicals from the reaction of ozone with a series of olefins (ethene, isoprene, trans-2-butene and 2,3 dimethyl-2-butene) in 4-6 torr of nitrogen. Using LIF to directly observe the steady-state of OH produced by the initial ozone-olefin reaction and subsequently destroyed by the OH-olefin reaction, we are able to establish OH yields broadly consistent with indirect values. The identification of the OH is unequivocal, and there is no indication that it is produced by a secondary process. To support these observations, we present a complete ab-initio potential energy surface for the O3-ethene reaction, extending from the reactants to available products.

  9. Nonlinear control of magnetic bearings

    Science.gov (United States)

    Pradeep, A. K.; Gurumoorthy, R.

    1994-01-01

    In this paper we present a variety of nonlinear controllers for the magnetic bearing that ensure both stability and robustness. We utilize techniques of discontinuous control to design novel control laws for the magnetic bearing. We present in particular sliding mode controllers, time optimal controllers, winding algorithm based controllers, nested switching controllers, fractional controllers, and synchronous switching controllers for the magnetic bearing. We show existence of solutions to systems governed by discontinuous control laws, and prove stability and robustness of the chosen control laws in a rigorous setting. We design sliding mode observers for the magnetic bearing and prove the convergence of the state estimates to their true values. We present simulation results of the performance of the magnetic bearing subject to the aforementioned control laws, and conclude with comments on design.

  10. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  11. Porphyrin Cobalt(III “Nitrene Radical” Reactivity; Hydrogen Atom Transfer from Ortho-YH Substituents to the Nitrene Moiety of Cobalt-Bound Aryl Nitrene Intermediates (Y = O, NH

    Directory of Open Access Journals (Sweden)

    Monalisa Goswami

    2016-02-01

    Full Text Available In the field of cobalt(II porphyrin-catalyzed metallo-radical reactions, organic azides have emerged as successful nitrene transfer reagents. In the pursuit of employing ortho-YH substituted (Y = O, NH aryl azides in Co(II porphyrin-catalyzed nitrene transfer reactions, unexpected hydrogen atom transfer (HAT from the OH or NH2 group in the ortho-position to the nitrene moiety of the key radical-intermediate was observed. This leads to formation of reactive ortho-iminoquinonoid (Y = O and phenylene diimine (Y = NH species. These intermediates convert to subsequent products in non-catalyzed reactions, as is typical for these free organic compounds. As such, the observed reactions prevent the anticipated cobalt-mediated catalytic radical-type coupling of the nitrene radical intermediates to alkynes or alkenes. Nonetheless, the observed reactions provide valuable insights into the reactivity of transition metal nitrene-radical intermediates, and give access to ortho-iminoquinonoid and phenylene diimine intermediates from ortho-YH substituted aryl azides in a catalytic manner. The latter can be employed as intermediates in one-pot catalytic transformations. From the ortho-hydroxy aryl azide substrates both phenoxizinones and benzoxazines could be synthesized in high yields. From the ortho-amino aryl azide substrates azabenzene compounds were obtained as the main products. Computational studies support these observations, and reveal that HAT from the neighboring OH and NH2 moiety to the nitrene radical moiety has a low energy barrier.

  12. Conversion of cyclohexane to cyclohexanol and cyclohexanone using H3[PMo12O40].nH2O-ZrOCl2 as catalyst

    Directory of Open Access Journals (Sweden)

    Eriza Sativa

    2017-07-01

    Full Text Available Synthesis and preparation polyoxometalate compound H3[-PMo12O40].nH2O supported with ZrOCl2 at various weights of ZrOCl2 i.e. 0.25 g, 0.50 g, 0.75 g, 1.00 g, 1.25 g, 0.01 g and 0.05 g to form H3[-PMo12O40].nH2O/ZrOCl2 have been conducted. These compound than was characterized through functional group analysis using FT-IR spectrophotometer and XRD analysis. The results showed that the optimal preparation was H3[-PMo12O40].nH2O/ZrOCl2  with support 0.05 g. FT-IR spectrum of H3[-PMo12O40].nH2O/ZrOCl2 show wavenumber at 1033.85 cm-1 for vibration P-O, 887.26 cm-1  for vibration M=O, 840.96 cm-1 and 655.80 cm-1   for vibration Mo-O-Mo. The existence of support was identified at wavenumber 1404.18 cm-1for vibration Zr-OH and 478.35 for vibration Zr-O-Zr. XRD powder analysis showed that material H3[-PMo12O40].nH2O/ZrOCl2 was amorphous material. Material H3[-PMo12O40].nH2O/ZrOCl2 was applied in oxidation of cyclohexane using hydrogen peroxide as oxidant. Oxidation process was optimized through reaction time H2O2 amount, temperature and catalyst weight. The results showed that the highest conversion in the using of H3[-PMo12O40].nH2O/ZrOCl2 catalyst found at 2 hours reaction time, 3 mL H2O2, 80oC temperature and 0.038 g catalyst with conversion 99.18 %. Selectivity of best reaction was 6.96 % for cyclohexanol and 24.9% for cyclohexanone, which was identified by GC-MS.           Keywords : H3[-PMo12O40].nH2O-ZrO2,cyclohexane, cyclohexanol, cyclohexanone.

  13. Functionalization of zeolitic cavities: grafting NH2 groups in framework T sites of B-SSZ-13--a way to obtain basic solids catalysts?

    Science.gov (United States)

    Regli, Laura; Bordiga, Silvia; Busco, Claudia; Prestipino, Carmelo; Ugliengo, Piero; Zecchina, Adriano; Lamberti, Carlo

    2007-10-10

    Insertion of B atoms into an Al-free zeolitic framework with CHA topology results in the formation of B-SSZ-13 zeotype with Si/B = 11. B K-edge NEXAFS testifies that B forms [B(OSi)4] units in a Td-like geometry (sp3-hybridized B atoms). According to B K-edge NEXAFS and IR, template burning results in the formation of [B(OSi)3] units in a D3h-like geometry (sp2-hybridized B atoms) with a break of a B-O-Si bond and the formation of a Si-OH group. The activated material contains B(III) Lewis acid centers able to specifically coordinate bases like NH3. Such [B(OSi)3] units are reactive toward ammonia, resulting in the formation of B-NH2 surface functionality inside the pores of B-SSZ-13 already under mild conditions, i.e., 35 mbar of NH3 at 373 K for 30 min and without crystallinity degradation. A minor fraction of Si-NH2 cannot be excluded owing to the presence of two IR doublets at 3500 and 3430 cm-1 and at 1600 and 1550 cm-1. Ab initio B3LYP/6-31+G(d,p) calculations on a cluster model, supported by a single-point MP2 on B3LYP/6-31+G(D,P) optimized structures, found the break by NH3 of a B-O-Si bond of the [B(OSi)3] unit with formation of [SiOH] and [H2N-B(OSi)2] species to be energetically favored. Comparison between experimental and computed frequency shifts shows them to be in semiquantitative agreement. The high stability of the B-NH2 surface functionality is probed by N K-edge NEXAFS spectra collected under UHV conditions. These findings can open a new route in the preparation of shape selective solid basic catalysts.

  14. Facile synthesis of Co(OH)2/Al(OH)3 nanosheets with improved electrochemical properties for asymmetric supercapacitor

    Science.gov (United States)

    Zhao, Cuimei; Ren, Fang; Cao, Yang; Xue, Xiangxin; Duan, Xiaoyue; Wang, Hairui; Chang, Limin

    2018-01-01

    Sheet-like Co(OH)2/Al(OH)3 or Co(OH)2 nanomaterial has been synthesized on conducting carbon fiber paper (CFP) by a facile one-step electrochemical deposition. The binder-free Co(OH)2/Al(OH)3/CFP displays an improved electrical conductivity, electrochemical activity and material utilization than solitary Co(OH)2, therefore Co(OH)2/Al(OH)3 nanomaterial exhibits improved electrochemical properties (a maximum capacitance of 1006 Fg-1 at 2 Ag-1, with 77% retention even at a high current density of 32 Ag-1, and more than 87% of the capacitance retention after 10000 cycles at 32 Ag-1) in comparison to that of the Co(OH)2/CFP (709 Fg-1, 65%, 79%). In addition, an asymmetric supercapacitor (ASC) fabricated with Co(OH)2/Al(OH)3/CFP positive electrode and AC/CFP negative electrode demonstrates ultrahigh specific capacitance (75.8 Fg-1) and potential window (1.7 V). These encouraging results make these low-cost and eco-friendly materials promising for high-performance energy storage application.

  15. 13C, 18O, and D Fractionation Effects in the Reactions of CH3OH Isotopologues with Cl andOH Radicals

    DEFF Research Database (Denmark)

    Feilberg, Karen; Gruber-Stadler, Margaret; Johnson, Matthew Stanley

    2008-01-01

    A relative rate experiment is carried out for six isotopologues of methanol and their reactions with OH and Cl radicals. The reaction rates of CH2DOH, CHD2OH, CD3OH, 13CH3OH, and CH3 18OH with Cl and OH radicals are measured by long-path FTIR spectroscopy relative to CH3OH at 298 ( 2 K and 1013 (...

  16. Synthesis of shape-controlled ZnSn(OH6 and gas sensing properties

    Directory of Open Access Journals (Sweden)

    HAN Lixian

    2013-02-01

    Full Text Available Monodisperse ZnSn(OH6(ZHS microcrystallites(MCs with two morphologies have been prepared through a facile preparation method without complicated steps,advanced experimental conditions or equipments.The morphology and compositional characteristics of the 3D hierarchitectures(HAs of ZHS MCs were investigated by various techniques such as XRD,FESEM,TEM,UV-vis spectra,BET.In the reaction system the morphology evolution from cube to sphere was controlled with adding different concentration of NH4OH.The gas sensors based on ZHS exhibited a good gas sensitivity to HCHO.However,the gas sensors based on spherical ZHS MCs exhibited the higher sensitivity,shorter recovery time and good reproducibility to HCHO than those of cubic ZHS MCs.More importantly,it was found that spherical ZHS MCs with ~600 nm size had the best gas-sensing properties owing to more oxygen vacancy defects,less band gap energy,and larger active surface area.

  17. Bias Gender Dalam Novel La Grande Borne Karya NH. Dini

    OpenAIRE

    Dilla, Raili Irfa; Thahar, Harris Effendi; Zulfikarni, Zulfikarni

    2013-01-01

    The purpose of this article was to describe the gender diffraction in novel La Grande Borne by Nh. Dini, evaluated from five aspects, (a) marginalization, (b) subordination, (c) stereotype, (d) violence, and (e) double work load. The data of this study was the sentences that refer to the gender diffraction.. The analyze technics were (1) describe the data, (2) analyze the data that refer to gender, (3) lnterpretated the unfair in gender, and (4) conclusion. The results of this study could be ...

  18. Coloring Jupiter's clouds: Radiolysis of ammonium hydrosulfide (NH4SH)

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2018-03-01

    Here we present our recent studies on the color and spectral reflectance changes induced by ∼0.9 MeV proton irradiation of ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. Ultraviolet-visible spectroscopy was used to observe and identify reaction products in the ice sample and digital photography was used to document the corresponding color changes at 10-160 K. Our experiments clearly show that the resulting color of the sample depends not only on the irradiation dose but also the irradiation temperature. Furthermore, unlike in our most recent studies of irradiation of NH4SH at 120 K, which showed that higher irradiation doses caused the sample to appear green, the lower temperature studies now show that the sample becomes red after irradiation. However, comparison of these lower temperature spectra over the entire spectral range observed by HST shows that even though the color and spectrum resemble the color and spectrum of the GRS, there is still enough difference to suggest that another component may be needed to adequately fit spectra of the GRS and other red regions of Jupiter's clouds. Regardless, the presence of NH4SH in the atmosphere of Jupiter and other gas giants, combined with this compound's clear alteration via radiolysis, suggests that its contribution to the ultraviolet-visible spectra of any of these object's clouds is significant.

  19. Fabrications of High-Capacity Alpha-Ni(OH2

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2017-03-01

    Full Text Available Three different methods were used to produce α-Ni(OH2 with higher discharge capacities than the conventional β-Ni(OH2, specifically a batch process of co-precipitation, a continuous process of co-precipitation with a phase transformation step (initial cycling, and an overcharge at low temperature. All three methods can produce α-Ni(OH2 or α/β mixed-Ni(OH2 with capacities higher than that of conventional β-Ni(OH2 and a stable cycle performance. The second method produces a special core–shell β-Ni(OH2/α-Ni(OH2 structure with an excellent cycle stability in the flooded half-cell configuration, is innovative and also already mass-production ready. The core–shell structure has been investigated by both scanning and transmission electron microscopies. The shell portion of the particle is composed of α-Ni(OH2 nano-crystals embedded in a β-Ni(OH2 matrix, which helps to reduce the stress originating from the lattice expansion in the β-α transformation. A review on the research regarding α-Ni(OH2 is also included in the paper.

  20. Keggin type polyoxometalate H4[αSiW12O40].nH2O as intercalant for hydrotalcite

    Directory of Open Access Journals (Sweden)

    Neza Rahayu Palapa

    2017-06-01

    Full Text Available The synthesis of hydrotalcite and polyoxometalate H4[αSiW12O40].nH2O with the ratio (2:1, (1:1, (1:2 and (1:3 has been done. The product of intercalation was characterized using FT-IR spectrophotometer, XRD, and TG-DTA. Polyoxometalate H4[αSiW12O40].nH2O intercalated layered double hydroxide was optimised to use as adsorbent Congo red dye. Characterization using FT-IR was not showing the optimal insertion process. The result using XRD characterization was showed successful of polyoxometalate H4[αSiW12O40].nH2O inserted layered double hydroxide with a ratio (1:1 which the basal spacing was expanded from 7,8 Ȧ to 9,81 Ȧ. Furthermore, the thermal analysis was performed using TG-DTA. The result show that the decomposition of polyoxometalate H4[αSiW12O40].nH2O intercalated  hydrotalcite with ratio (1:1 was occured at 80oC to 400oC with a loss of OH in the layer at 150oC to 220oC, and then the decomposition of the compound polyoxometalate H4[αSiW12O40].nH2O at 350oC to 420oC. Keywords: Hydrotalcite, Layered Double Hydroxide, Polyoxometalate, Intercalation

  1. Water contents and OH speciation in pyroxenes

    Science.gov (United States)

    Bégaudeau, K.; Morizet, Y.; Mercier, J.

    2010-12-01

    Nominally anhydrous minerals such as pyroxene contain trace amounts of hydrogen which reside in structural defects. Dissolved water (hydroxyls species OH) plays a crucial role in modifying the physical and chemical properties of the Earth’s mantle and attests a significant water reservoir inside. For a series of natural clino- and orthopyroxenes (cpx and opx) from large suite mantle xenoliths, we investigated the total water (H2Otot) in pyroxenes using micro-FTIR so as to constrain the OH dissolution mechanisms. Samples studied have been brought up either by 1) alkaline basalts magmas, Mont Briançon, Maar de Borée , Barges (France), Dreiser Weiher (Germany), San Carlos (Arizona), Black Rock Sumitt (Nevada), Kilbourne Hole (New Mexico), or by 2) kimberlite magmas, Letseng-la-Terae (South Africa). Crystal chemistry from the different xenoliths was determined by microprobe analyses. Pyroxenes have high Mg number (about 0.9) and spinels contain 0.19 Fe3+/Fetot. Equilibrium P, T conditions were determined by geothermobarometry. P-T conditions were estimated between 700 and 1400°C and between 0.5 and 6.3 GPa. Polarized FTIR spectra acquired on natural cpx and opx are consistent with previous studies, showing the main absorption bands attributed to OH species in the region between 3000-3800 cm-1. H2Otot was estimated by the Beer-Lambert law using the calibration of Libowitzky and Rossman (1997) and gives about 300 ppm and 100 ppm H2O for cpx and opx, respectively. Partionning coefficient between cpx and opx is estimated to 2.1, similar to those from literature data on pyroxenes of alkali-basalt and kimberlitic xenoliths. The H2Otot does not show significant correlation with crystal chemistry, therefore contrasting with previous studies. However, we observe a good linear correlation between the cpx/opx water content and the physical conditions (P, T and fO2 determined from Fe3+/Fetot in spinel) recorded by the mantle xenoliths: ppm H2Ocpx=522.89-119.38*P-0.195*T+484

  2. DESIGN HANDBOOK ON GAS BEARINGS FOR GYROSCOPES.

    Science.gov (United States)

    consisting of a plain journal for supporting radial loads flanked by two spiral-grooved thrust bearings to support double-acting thrust loads; (3) the spiral-grooved journal bearing ; and (4) the spiral-grooved conical bearing.

  3. Hybrid Hydrostatic/Transient Roller Bearing Assembly

    Science.gov (United States)

    Justak, John F.

    1992-01-01

    Proposed bearing assembly for shaft of high-speed turbopump includes both hydrostatic and rolling-element bearings. Rolling-element bearing unloaded at high speed by centrifugal expansion of outer race and transient retainer.

  4. Two pad axially grooved hydrostatic bearing

    Science.gov (United States)

    San Andres, Luis A. (Inventor)

    1995-01-01

    A hydrostatic bearing having two axial grooves on opposite sides of the bearing for breaking the rotational symmetry in the dynamic force coefficients thus reducing the whirl frequency ratio and increasing the damping and stiffness of the hydrostatic bearing.

  5. Deformation Analysis of Fixed Bearing Inclined Plane Thrust Bearing

    Directory of Open Access Journals (Sweden)

    LI Yong--hai

    2017-02-01

    Full Text Available According to the theory of lubrication,Numerical simulation of the deformation of the thrust bearing of the fixed inclined plane was carried out,by finite element numerical analysis method and using the ANSYS software. The mathematical model of the oil film shape control equations about of the deformation and bearing is established. Analytical result showed that the force caused the tile surface generating concave deformation,and convex deformation increased with the height and the size of the load and bearing;Tile surface temperature generated convex deformation and increased with the height and the size of the temperature of bearing bush;The actual deformation of the tile surface is the superposition of the force and the thermal deformation. This conclusion can provide reference for the design and the application of thrust bearing,to reduce the tile surface,which is not conducive to the carrying capacity of the concave deformation.

  6. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  7. Exploring the crystallization landscape of cadmium bis(N-hydroxyethyl, N-isopropyldithiocarbamate), Cd[S{sub 2}CN(iPr)CH{sub 2}CH{sub 2}OH]{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Yee Seng; Halim, Siti Nadiah Abdul [Malaya Univ., Kuala Lumpur (Malaysia). Dept. of Chemistry; Tiekink, Edward R.T. [Malaya Univ., Kuala Lumpur (Malaysia). Dept. of Chemistry; Sunway Univ., Bandar Sunway (Malaysia). Centre for Chemical Crystallography

    2016-04-01

    Crystallization of Cd[S{sub 2}CN(iPr)CH{sub 2}CH{sub 2}OH]{sub 2} from ethanol yields the coordination polymer [{Cd[S_2CN(iPr)CH_2CH_2OH]_2}.EtOH]{sub ∞} (1) within 3 h. When the solution is allowed to stand for another hour, the needles begin to dissolve and prisms emerge of the supramolecular isomer (SI), binuclear {Cd[S_2CN(iPr)CH_2CH_2OH]_2}{sub 2}.2EtOH (2). These have been fully characterized spectroscopically and by X-ray crystallography. Polymeric 1 has 2-fold symmetry and features dithiocarbamate ligands coordinating two octahedral Cd atoms in a μ{sub 2}κ{sup 2}-tridentate mode. Binuclear 2 is centrosymmetric with two ligands being μ{sub 2}κ{sup 2}-tridentate as for 1 but the other two being κ{sup 2}-chelating leading to square pyramidal geometries. The conversion of the kinetic crystallization product, 1, to thermodynamic 2 is irreversible but transformations mediated by recrystallization (ethanol and acetonitrile) to related literature SI species, namely coordination polymer [{Cd[S_2CN(iPr)CH_2CH_2OH]_2}{sub 3}.MeCN]{sub ∞} and binuclear {Cd[S_2CN(iPr)CH_2CH_2OH]_2}{sub 2}.2H{sub 2}O.2MeCN, are demonstrated, some of which are reversible. Three other crystallization outcomes are described whereby crystal structures were obtained for the 1:2 co-crystal {Cd[S_2CN(iPr)CH_2CH_2OH]_2}{sub 2}:2[3-(propan-2-yl)-1,3-oxazolidine-2-thione] (3), the salt co-crystal [iPrNH{sub 2}(CH{sub 2}CH{sub 2}OH)]{sub 4}[SO{sub 4}]{sub 2}{Cd[S_2CN(iPr)CH_2CH_2OH]_2}{sub 2} (4) and the salt [iPrNH{sub 2}(CH{sub 2}CH{sub 2}OH)]{Cd[S_2CN(iPr)CH_2CH_2OH]_3} (5). These arise as a result of decomposition/oxidation of the dithiocarbamate ligands. In each of 3 and 4 the binuclear {Cd[S_2CN(iPr)CH_2CH_2OH]_2}{sub 2} SI, as in 2, is observed strongly suggesting a thermodynamic preference for this form.

  8. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  9. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  10. Short-term effects of natural and NH4+-enriched chabazite zeolitite amendments to soil microbial biomass

    Science.gov (United States)

    Ferretti, Giacomo; Keiblinger, Katharina Maria; Di Giuseppe, Dario; Faccini, Barbara; Colombani, Nicolò; Zechmeister-Boltenstern, Sophie; Coltorti, Massimo; Mastrocicco, Micòl

    2017-04-01

    Natural zeolite-bearing rocks (zeolitites) are known to be a suitable material for agricultural purposes by improving soil physicochemical properties and nitrogen use efficiency (NUE). However, little is known about their effects on soil microbial biomass. Aim of this work is to evaluate short-term effects of different chabazite-zeolitite amendments on soil microbial biomass (and activity). To this purpose a silty-clay agricultural soil was amended in three different ways, by the addition of 5 and 15 wt% of natural chabazite zeolitites (NZ) and 10 wt% of NH4+-enriched chabazite zeolitites (CZ). Soil pH, water content, dissolved organic carbon (C), total dissolved N, NH4+, NO3-, NO2-, microbial biomass C and N and ergosterol were periodically measured over a time course of 16 days in a laboratory incubation experiment. In order to verify the immobilization of N derived from CZ into microbial biomass, the δ15N signature of microorganisms was evaluated by the Extraction-Fumigation-Extraction method followed by EA-IRMS analysis. This latter investigation was possible because zeolitites were enriched with NH4+ derived from pig-slurry, which have a very high 15N natural abundance that allow to trace microbial incorporation. Soil amended with 5 wt% of NZ showed increased ergosterol content as well as microbial C/N ratio starting from day 9 of incubation, suggesting that fungal biomass was probably favored, although the same behavior was not found in the soil amended with 15 wt% of the same material. On the other hand, the NH4+-enriched CZ showed strong interactions with soil microbial biomass N. Isotopic measurements supported microbial assimilation of the N introduced with CZ since the second day of incubation. The high dissolved organic C and microbial biomass N suggested an increase of mineralization and immobilization processes. In addition, in CZ amended soil, microbial biomass N was related to NO3- production over time and inversely related to NH4+, suggesting high

  11. Study of vibrational spectra of NH sub 4 Cl and NH sub 4 Br at high pressure

    CERN Document Server

    Glazkov, V P; Syrykh, G F; Kozlenko, D P; Savenko, B N; Telepnev, A S

    2002-01-01

    The NH sub 4 Cl vibrational spectra at the pressures up to 2.6 GPa and the NH sub 4 Br spectra at the pressures up to 7 GPa are studied through the method of the neutrons inelastic incoherent scattering. It is established that the linear baric dependence of the libration mode changes its inclination in the area above the pressure of transition from the disordered cubic phase to the ordered cubic phase with the CsCl-type structure. The baric dependence inclination of the cross-sectional optical translation mode remains unchanged. The evaluations of the Grueneisen parameters are presented in the one-dimensional approximation and the form of the potential function for the libration oscillations in the disordered and ordered cubic phases with the CsCl-type structure is calculated. It is shown that the observed effects are related to the high anharmonism of the potential in the disordered phase

  12. Thin Dense Chrome Bearing Insertion Program

    National Research Council Canada - National Science Library

    Rhoads, Mark

    1997-01-01

    .... TDC coated bearings demonstrated improved corrosion and contamination resistance. TDC coated bearings also demonstrated acceptable performance during thermal cycle, oil-off, and induced defect conditions...

  13. Rapid Aluminum Nanoparticle Production by Milling in NH3 and CH3NH2 Atmospheres: An Experimental and Theoretical Study

    Science.gov (United States)

    2015-07-01

    functionalization enhances size reduction by reducing the surface free energy and the tendency toward mechanochemical welding . For both NH3 and MMA, the...mixtures of nano and micron size particles, with nanoparticles making up less than 50% of the product mass under the best conditions. Although it is... nanoparticle production is more efficient in these gases than in reactive liquid milling agents, including alkylamines. Furthermore, the particle size

  14. Total Syntheses and Initial Evaluation of [Ψ[C(=S)NH]Tpg4]vancomycin, [Ψ[C(=NH)NH]Tpg4]vancomycin, [Ψ[CH2NH]Tpg4]vancomycin and their (4-Chlorobiphenyl)methyl Derivatives: Synergistic Binding Pocket and Peripheral Modifications for the Glycopeptide Antibiotics

    Science.gov (United States)

    Okano, Akinori; Nakayama, Atsushi; Wu, Kejia; Lindsey, Erick A.; Schammel, Alex W.; Feng, Yiqing; Collins, Karen C.

    2015-01-01

    Full details of studies are disclosed on the total synthesis of binding pocket analogues of vancomycin, bearing the peripheral L-vancosaminyl-1,2-D-glucosyl disaccharide, that contain changes to a key single atom in the residue 4 amide (residue 4 carbonyl O → S, NH, H2) designed to directly address the underlying molecular basis of resistance to vancomycin. Also disclosed are studies piloting the late stage transformations conducted on the synthetically more accessible C-terminus hydroxymethyl aglycon derivatives and full details of the peripheral chlorobiphenyl functionalization of all the binding pocket modified vancomycin analogues designed for dual D-Ala-D-Ala/D-Ala-D-Lac binding are reported. Their collective assessment indicate that combined binding pocket and chlorobiphenyl peripherally modified analogues exhibit a remarkable spectrum of antimicrobial activity (VSSA, MRSA, VanA and VanB VRE) and impressive potencies against both vancomycin-sensitive and vancomycin-resistant bacteria (MICs = 0.06–0.005 μg/mL and 0.5–0.06 μg/mL for the amidine and methylene analogues, respectively) and likely benefit from two independent and synergistic mechanisms of action, only one of which is dependent on D-Ala-D-Ala/D-Ala-D-Lac binding. Such analogues are likely to display especially durable antibiotic activity not prone to rapidly acquired clinical resistance. PMID:25750995

  15. Certification of OHS management in a Nordic context

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Jørgensen, Kirsten; Jørgensen, Ulrik

    2009-01-01

    for the involved stakeholders. The consequences of these foundational elements of the existing management standard are analysed and exemplified. The Nordic Minister Council has funded the project, OHS Certification as Control Instrument and Control Strategy, which together with earlier studies of the working...... in an interaction between stakeholders including researchers, OHS professionals, and the labour market organisations and has to a large degree been reflected in the Nordic countries OHS legislation. In the last decade the use of OHS management systems has been taken up in Danish legislation as a complement...... to the traditional command and control regulation. This has triggered a debate on how OHS management systems operate and impact the working environment. This article present a study of how OHS management systems in the form of OHSAS 18001 is constructed and how they reflect existing regulatory practices...

  16. Mixed-mu superconducting bearings

    Science.gov (United States)

    Hull, John R.; Mulcahy, Thomas M.

    1998-01-01

    A mixed-mu superconducting bearing including a ferrite structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet structure. The ferrite structure is levitated by said stationary permanent magnet structure.

  17. Simplified installation of thrust bearings

    Science.gov (United States)

    Sensenbaugh, N. D.

    1980-01-01

    Special handling sleeve, key to method of installing thrust bearings, was developed for assembling bearings on shaft of low-pressure oxygen turbo-pump. Method eliminates cooling and vacuum-drying steps which saves time, while also eliminating possibility of corrosion formation. Procedure saves energy because it requires no liquid nitrogen for cooling shaft and no natural gas or electric power for operating vacuum oven.

  18. Lateral dampers for thrust bearings

    Science.gov (United States)

    Hibner, D. H.; Szafir, D. R.

    1985-01-01

    The development of lateral damping schemes for thrust bearings was examined, ranking their applicability to various engine classes, selecting the best concept for each engine class and performing an in-depth evaluation. Five major engine classes were considered: large transport, military, small general aviation, turboshaft, and non-manrated. Damper concepts developed for evaluation were: curved beam, constrained and unconstrained elastomer, hybrid boost bearing, hydraulic thrust piston, conical squeeze film, and rolling element thrust face.

  19. 75 FR 65585 - Proposed Establishment of Class E Airspace; Lancaster, NH

    Science.gov (United States)

    2010-10-26

    ...-0323; Airspace Docket No. 10-ANE-106] Proposed Establishment of Class E Airspace; Lancaster, NH AGENCY... to establish Class E airspace at Weeks Medical Center Heliport, Lancaster, NH. The NPRM is being... Lancaster, NH to accommodate special standard instrument approach procedures for Weeks Medical Center...

  20. 75 FR 42630 - Proposed Establishment of Class E Airspace; Lancaster, NH

    Science.gov (United States)

    2010-07-22

    ...-0323; Airspace Docket No. 10-ANE-106] Proposed Establishment of Class E Airspace; Lancaster, NH AGENCY... action proposes to establish Class E Airspace at Lancaster, NH, to accommodate a new Area Navigation... Lancaster, NH to provide controlled airspace required to support the special SIAPs for Weeks Medical Center...

  1. 75 FR 81517 - Proposed Establishment of Class E Airspace; Lancaster, NH

    Science.gov (United States)

    2010-12-28

    ...-1009; Airspace Docket No. 10-ANE-111] Proposed Establishment of Class E Airspace; Lancaster, NH AGENCY... action proposes to establish Class E Airspace at Lancaster, NH to accommodate a new Area Navigation (RNAV... Federal Regulations (14 CFR) part 71 to establish Class E airspace at Lancaster, NH providing the...

  2. Radial magnetic bearings: An overview

    Directory of Open Access Journals (Sweden)

    Weiyu Zhang

    Full Text Available Radial magnetic bearings (RMBs are one of the most commonly used magnetic bearings. They are used widely in the field of ultra-high speed and ultra-precise numerical control machine tools, bearingless motors, high speed flywheels, artificial heart pumps, and molecular pumps, and they are being strengthened and extended in various important areas. In this paper, a comprehensive overview is given of different bearing topologies of RMBs with different stator poles that differ in their construction, the driving mode of electromagnets, power consumption, cost, magnetic circuits, and symmetry. RMBs with different poles and couplings between the two bearing axes in the radial direction responsible for cross-coupling generation are compared. In addition, different shaped rotors are compared, as the performances of magnetic bearing-rotor systems are of great concern to rotor constructions. Furthermore, the parameter design methods, the mathematical models and control strategies of the RMBs are described in detail. From the comparison of topologies, models and control methods for RMBs, the advantages, disadvantages and utilizable perspectives are also analyzed. Moreover, several possible development trends of the RMBs are discussed. Keywords: Radial magnetic bearings (RMBs, Topologies, Mathematical mode, Control strategies, Development trends

  3. Preparation of silver chloride nanoparticles by a mechanical treatment of the system NH4Cl−AgNO3−NH4NO3

    Directory of Open Access Journals (Sweden)

    Farit Urakaev

    2014-08-01

    Full Text Available Silver chloride nanoparticles dispersed within ammonium nitrate matrix have been prepared though displacement mechanochemical reaction NH4Cl + AgNO3 + z NH4NO3 = (z+1 NH4 NO3 + AgCl at various z coefficients z1 = 7.22 and z2 = 3.64. The intermediate compound of NH4Ag(NO32 were recorded after mechanochemical processing of studied system. By using simultaneous TG and DSC measurements possibilities to prepare silver chloride in its free form have been discussed by using thermal treatment.

  4. Crystal structure and magnetism of Fe2(OH)[B2O4(OH)

    DEFF Research Database (Denmark)

    Kurayoshi, Yotaro; Hara, Shigeo; Sato, Hirohiko

    2014-01-01

    The structure and magnetism of Fe2(OH)[B2O4(OH)] are reported. Powder x-ray diffraction reveals a characteristic structure containing two crystallographically independent zigzag-ladder chains of magnetic Fe2+ ions. Magnetization measurements reveal a phase transition at 85 K, below which a weak...... spontaneous magnetization (approximate to 0.15 μB/Fe) appears. Below 85 K, magnetization increases with decreasing temperature down to 70 K, below which it decreases and approaches a constant value at low temperature. The Mossbauer spectrum at room temperature is composed of two paramagnetic doublets...... corresponding to the two crystallographic Fe2+ sites. Below 85 K, each doublet undergoes further splitting because of the magnetic hyperfine fields. The temperature dependence of the hyperfine field is qualitatively different for the two distinguishable Fe2+ sites. This is responsible for the anomalous...

  5. DFT study on the attacking mechanisms of H and OH radicals to G-C and A-T base pairs in water

    International Nuclear Information System (INIS)

    Okutsu, N.; Shimamura, K.; Shimizu, E.; Kurita, N.; Shulga, S.; Danilov, V. I.

    2016-01-01

    To elucidate the effect of radicals on DNA base pairs, we investigated the attacking mechanism of OH and H radicals to the G-C and A-T base pairs, using the density functional theory (DFT) calculations in water approximated by the continuum solvation model. The DFT calculations revealed that the OH radical abstracts the hydrogen atom of a NH 2 group of G or A base and induces a tautomeric reaction for an A-T base pair more significantly than for a G-C base pair. On the other hand, the H radical prefers to bind to the Cytosine NH 2 group of G-C base pair and induce a tautomeric reaction from G-C to G*-C*, whose activation free energy is considerably small (−0.1 kcal/mol) in comparison with that (42.9 kcal/mol) for the reaction of an A-T base pair. Accordingly, our DFT calculations elucidated that OH and H radicals have a significant effect on A-T and G-C base pairs, respectively. This finding will be useful for predicting the effect of radiation on the genetic information recorded in the base sequences of DNA duplexes

  6. Elasticity of Hydrous Aluminosilicate Mineral, Topaz-OH (Al2SiO4(OH)2) at High Pressures

    Science.gov (United States)

    Hariharan, A.; Mookherjee, M.; Tsuchiya, J.

    2015-12-01

    We examined the equation of state and high-pressure elasticity of the hydrous aluminosilicate mineral topaz-OH (Al2SiO4(OH)2) using first principles simulation. Topaz-OH is a hydrous phase in the Al2O3-SiO2-H2O (ASH) ternary system, which is relevant for the mineral phase relations in the hydrated sedimentary layer of subducting slabs. Based on recent experiments, it is known that the protons in the topaz-OH exhibit positional disorder with half occupancy over two distinct crystallographic sites. In order to adequately depict the proton environment in the topaz-OH, we examined five crystal structure models with distinct configuration for the protons. Upon full geometry optimization, we find that there are two distinct crystal structures for the topaz-OH. The first crystal structure has an orthorhombic Pbnm space group symmetry, and the second crystal structure has a monoclinic P21/c space group symmetry. At static conditions, the monoclinic (P21/c) topaz-OH has lower energy compared to the orthorhombic (Pbnm) topaz-OH. The energy of the monoclinic (P21/c) topaz-OH remains stable at least up to 40 GPa, i.e., pressures beyond the thermodynamic stability of the topaz-OH. Based on the results from first principles simulation, the equation of state for the monoclinic topaz-OH is well represented by a third-order Birch-Murnaghan formulation, with V0 = 348.63 (±0.04) Å3, K0 = 164.7 (±0.04) GPa, and K'0 = 4.24 (±0.05). The equation of state for the orthorhombic topaz-OH is well represented by a third-order Birch-Murnaghan formulation, with V0 = 352.47 (±0.04) Å3, K0 = 166.4 (±0.06) GPa, and K'0 = 4.03 (±0.04). While the bulk modulus is very similar for both the monoclinic and orthorhombic topaz-OH, the shear elastic moduli are very sensitive to the position of the proton and the orientation of the hydroxyl (O-H) groups. In the hydrated sedimentary layer of a subducting slab, transformation of a mineral assemblage consisting of coesite (SiO2) and diaspore (AlOOH) to

  7. Trichinella nativa in a black bear from Plymouth, New Hampshire.

    Science.gov (United States)

    Hill, D E; Gamble, H R; Zarlenga, D S; Coss, C; Finnigan, J

    2005-09-05

    A suspected case of trichinellosis was identified in a single patient by the New Hampshire Public Health Laboratories in Concord, NH. The patient was thought to have become infected by consumption of muscle larvae (ML) in undercooked meat from a black bear killed in Plymouth, NH in October 2003 and stored frozen at -20 degrees C fro 4 months. In January 2004, a 600 g sample of the meat was thawed at 4 degrees C, digested in hydrochloric acid and pepsin, and larvae were collected by sedimentation. Intact, coiled, and motile ML were recovered (366 larvae per gram (l pg) of tissue), which were passed into mice and pigs. Multiplex PCR revealed a single 127 bp amplicon, indicative of Trichinella nativa. The Reproductive Capacity Index (RCI) for the T. nativa-Plymouth isolate in mice was 24.3. Worm burdens in the diaphragms of two 3-month-old pigs given 2,500 ML were 0.05 and 0.2l pg by 35 days post-inoculation, while 2.2 and 0.75 l pg were recovered from two 3-month-old pigs given 10,000 ML; no larvae were recovered from four 1-year-old pigs given 2,500 ML (n=2) or 10,000 ML (n=2). Viable larvae were also recovered from frozen black bear meat harvested at two additional locations, one in southern Ontario, Canada, and one in upstate New York, USA. Multiplex PCR using genomic DNA from these parasite samples demonstrated that both isolates were T. nativa. This is the first report of the freeze-resistant species, T. nativa, within the continental United States.

  8. Ultrasonic irradiation-promoted one-pot synthesis of CH3NH3PbBr3 quantum dots without using flammable CH3NH2 precursor

    Science.gov (United States)

    Jiang, Han; Wang, Chunlei; Lv, Changgui; Xu, Shuhong; Zhu, Li; Zhang, Ruohu; Cui, Yiping

    2017-02-01

    At present, the CH3NH3PbBr3 quantum dots (QDs) reported in the literature usually contain two synthesis steps: the initial preparation of CH3NH3Br via the reaction of flammable CH3NH2 and HBr, together with the subsequent formation of CH3NH3PbBr3 QDs. To avoid the use of dangerous CH3NH2, this work develops a novel one-pot method for synthesizing CH3NH3PbBr3 QDs using safe and commercially available reactants (CH3NH3Cl, KBr and PbCl2). It is found that ultrasonic treatment plays a key role during the synthesis of CH3NH3PbBr3 QDs. Without ultrasonic irradiation, it is not possible to synthesize CH3NH3PbBr3 QDs under heating or vigorous stirring. Aliquots of samples taken at different ultrasonic irradiation time intervals show a time-dependent redshift in the emission wavelength. This suggests the formation of CH3NH3PbCl3 QDs first, followed by the formation of CH3NH3PbBr3 QDs through ultrasonically promoted halide exchange. Moreover, mixed CH3NH3PbCl x Br3-x QDs with a tunable emission wavelength can also be prepared through this one-pot method by controlling the ultrasonic irradiation time. In comparison to the previous two-step method, the current one-pot method is simpler, less time-consuming and does not use flammable CH3NH2. The as-prepared CH3NH3PbBr3 QDs show a comparable photoluminescence (PL) quantum yield (QY) to that of the literature. What is more, the ultrasonic time-controlled emission wavelength of CH3NH3PbCl x Br3-x QDs also provides an alternative way of tuning QD emission to the traditional way of controlling the halide ratios.

  9. A liquid-based eutectic system: LiBH4·NH 3-nNH3BH3 with high dehydrogenation capacity at moderate temperature

    KAUST Repository

    Tan, Yingbin

    2011-01-01

    A novel eutectic hydrogen storage system, LiBH4·NH 3-nNH3BH3, which exists in a liquid state at room temperature, was synthesized through a simple mixing of LiBH 4·NH3 and NH3BH3 (AB). In the temperature range of 90-110 °C, the eutectic system showed significantly improved dehydrogenation properties compared to the neat AB and LiBH 4·NH3 alone. For example, in the case of the LiBH4·NH3/AB with a mole ratio of 1:3, over 8 wt.% hydrogen could be released at 90 °C within 4 h, while only 5 wt.% hydrogen released from the neat AB at the same conditions. Through a series of experiments it has been demonstrated that the hydrogen release of the new system is resulted from an interaction of AB and the NH3 group in the LiBH4·NH3, in which LiBH4 works as a carrier of ammonia and plays a crucial role in promoting the interaction between the NH3 group and AB. The enhanced dehydrogenation of LiBH 4·NH3/AB may result from the polar liquid state reaction environments and the initially promoted formation of the diammoniate of diborane, which will facilitate the B-H⋯H-N interaction between LiBH4·NH3 and AB. Kinetics analysis revealed that the rate-controlling steps of the dehydrogenation process are three-dimensional diffusion of hydrogen at temperatures ranging from 90 to 110 °C. This journal is © The Royal Society of Chemistry.

  10. 36 CFR 13.1236 - Bear orientation.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear Orientation. Failure to receive an NPS-approved Bear Orientation is prohibited. ...

  11. 49 CFR 229.69 - Side bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

  12. Heuristic Explanation of Journal Bearing Instability

    Science.gov (United States)

    1982-05-01

    A fluid-filled journal bearing is viewed as a powerful pump circulating fluid around the annular space between the journal and the bearing. A small...other simple explanations of journal - bearing instability. It is shown that for non-cavitating long bearings the hypothesis predicts instability onset

  13. Descriptor-Based Analysis Applied to HCN Synthesis from NH3 and CH4

    Energy Technology Data Exchange (ETDEWEB)

    Grabow, L

    2011-08-18

    The design of solid metal catalysts using theoretical methods has been a long-standing goal in heterogeneous catalysis. Recent developments in methodology and computer technology as well as the establishment of a descriptor-based approach for the analysis of reaction mechanisms and trends across the periodic table allow for the fast screening for new catalytic materials and have lead to first examples of computational discoveries of new materials. The underlying principles of the descriptor-based approach are the existence of relations between the surface electronic structure, adsorption energies and activation barriers that result in volcano-shaped activity plots as function of simple descriptors, such as atomic binding energies or the d-band center. Linear scaling relations have been established between the adsorption energies of hydrogen-containing molecules such as CH{sub x}, NH{sub x}, OH{sub x} and SH{sub x} and the C, N O and S adsorption energies on transition-metal surfaces. Transition-state energies have also been shown to scale linearly with adsorption energies in a similar fashion. Recently, a single transition state scaling relation has been identified for a large number of C-C, C-O, C-N, N-O, N-N, and O-O coupling reactions. The scaling relations provide a powerful tool for the investigation of reaction mechanisms and the prediction of potential energy surfaces. They limit the number of independent variables to a few, typically adsorption energies of key atoms. Using this information as input to a microkinetic model provides an understanding of trends in catalytic activity across the transition metals. In most cases a volcano-shaped relation between activity and the key variables, the descriptors, is observed. In the present paper we will provide an example of the approach outlined above and show how one can obtain an understanding of activity/selectivity trends of a reaction with just a few new calculations.

  14. Several notes on the OH* layer

    Directory of Open Access Journals (Sweden)

    M. Grygalashvyly

    2015-07-01

    Full Text Available This brief note introduces several analytical approaches to OH* layer parameters. The number density and height of the OH* layer peak are determined by the distributions of atomic oxygen and temperature, and by corresponding vertical gradients. The theory can be applied to satellite-borne and ground-based airglow measurements, as well as to model results.

  15. New route for synthesis of electrocatalytic Ni (OH) 2 modified ...

    Indian Academy of Sciences (India)

    Immobilization of redox species like Ni(OH)2 onto the electrode surface is important in the application areas such as super capacitor, electrochromic displays and electrocatalysis. Nickel hexacyanoferrate (NiHCF) modified glassy carbon could be further derivatized with Ni(OH)2 by electrochemical cycling in alkali.

  16. Observations of OH and HO2 radicals in coastal Antarctica

    Directory of Open Access Journals (Sweden)

    S. J.-B. Bauguitte

    2007-08-01

    Full Text Available OH and HO2 radical concentrations have been measured in the boundary layer of coastal Antarctica for a six-week period during the austral summer of 2005. The measurements were performed at the British Antarctic Survey's Halley Research Station (75° 35' S, 26° 19' W, using the technique of on-resonance laser-induced fluorescence to detect OH, with HO2 measured following chemical conversion through addition of NO. The mean radical levels were 3.9×105 molecule cm−3 for OH, and 0.76 ppt for HO2 (ppt denotes parts per trillion, by volume. Typical maximum (local noontime levels were 7.9×105 molecule cm−3 and 1.50 ppt for OH and HO2 respectively. The main sources of HOx were photolysis of O3 and HCHO, with potentially important but uncertain contributions from HONO and higher aldehydes. Of the measured OH sinks, reaction with CO and CH4 dominated, however comparison of the observed OH concentrations with those calculated via the steady state approximation indicated that additional co-reactants were likely to have been present. Elevated levels of NOx resulting from snowpack photochemistry contributed to HOx cycling and enhanced levels of OH, however the halogen oxides IO and BrO dominated the CH3O2 – HO2 – OH conversion in this environment, with associated ozone destruction.

  17. Modelling atmospheric OH-reactivity in a boreal forest ecosystem

    DEFF Research Database (Denmark)

    Mogensen, D.; Smolander, S.; Sogachev, Andrey

    2011-01-01

    We have modelled the total atmospheric OH-reactivity in a boreal forest and investigated the individual contributions from gas phase inorganic species, isoprene, monoterpenes, and methane along with other important VOCs. Daily and seasonal variation in OH-reactivity for the year 2008 was examined...

  18. Superconductor bearings, flywheels and transportation

    Science.gov (United States)

    Werfel, F. N.; Floegel-Delor, U.; Rothfeld, R.; Riedel, T.; Goebel, B.; Wippich, D.; Schirrmeister, P.

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS-FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN2. More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  19. Observations of HC5N and NH3 in Taurus

    International Nuclear Information System (INIS)

    Myers, P.C.; Ho, P.T.P.; Benson, P.J.

    1979-01-01

    Observations of HC 5 N lines toward TMC-2 indicate that it is a small (Lapprox.0.1 pc), dense (napprox.4 x 10 4 cm -3 ), low-mass (Mapprox.1 M/sub sun/) fragment in the Taurus complex, with velocity dispersion at the emission peak only about twice thermal (Δvapprox.0.2 km s -1 ). The HC 5 N emission region in TMC-2 has roughly half the projected area of that in TMC-1, and is more round than filamentary. The HC 5 N and NH 3 emission regions in TMC-2 are coincident, with N (HC 5 N)/N (NH 3 ) approx.0.1. The line width is much smaller than the free-fall width; the deduced values of L, n, and T satisfy the virial-theorem requirement for stable equilibrium. The temporary equilibrium of such fragments may serve to lengthen the time scales for formation of low-mass stars and long-chain molecules

  20. Photoacoustic detection of NH3 in power plant emissions

    International Nuclear Information System (INIS)

    Rassmussen, O.

    1991-01-01

    The paper describes a photoacoustic spectrometer initially designed for detection of NH 3 in power plant emission with a detection limit below 1 ppm. The radiation source is a high tunable CO 2 waveguide laser emitting its own frequency standard in one of 90 laserlines. The detection is performed at reduced pressure where the vibration-rotation transitions give an unambiguous fingerprint for each trace gas. Immunity against interference is ensured by recording this characteristic spectral fingerprint over the tuning range of the laser, and problems associated with the high concentration of CO 2 or other interfering molecules are further eliminated by utilizing the effect of kinetic cooling in the photoacoustic phase. The use of a CO 2 laser as radiation source combined with the highly sensitive photoacoustic detection provides a great possibility of measuring a wide range of air pollutants in the range down to ppt concentrations. Experimental measurements have been carried out on gases like sulfur dioxide, ethylene, sulfur hexafluoride, vinylchloride, ozone, etc., and many others have been theoretically examined to give a high response in the CO 2 laser frequency range. A computerized NH 3 spectrometer has been constructed and tested under realistic conditions at a Danish power plant operating a test facility for selective non-catalytic reduction of NO x . Results of this test will be presented

  1. Treatment for GaSb surfaces using a sulphur blended (NH4)2S/(NH4)2SO4 solution

    International Nuclear Information System (INIS)

    Murape, D.M.; Eassa, N.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

    2012-01-01

    A sulphur based chemical, [(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na 2 S·9H 2 O and (NH 4 ) 2 S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) than with (NH 4 ) 2 S or Na 2 S·9H 2 O, as evidenced by the ratio of the O 506eV to Sb 457eV AES peaks. XPS results reveal that Sb 2 S 3 /Sb 2 S 5 “replaces” Sb 2 O 3 /Sb 2 O 5 , suggesting that sulphur atoms substitute oxygen atoms in Sb 2 O 3 /Sb 2 O 5 to form Sb-S. It seems sulphurization only partially removes Ga 2 O 3 . Treatment with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

  2. Increasing Hydrogen Density with the Cation-Anion Pair BH4−-NH4+ in Perovskite-Type NH4Ca(BH43

    Directory of Open Access Journals (Sweden)

    Pascal Schouwink

    2015-08-01

    Full Text Available A novel metal borohydride ammonia-borane complex Ca(BH42·NH3BH3 is characterized as the decomposition product of the recently reported perovskite-type metal borohydride NH4Ca(BH43, suggesting that ammonium-based metal borohydrides release hydrogen gas via ammonia-borane-complexes. For the first time the concept of proton-hydride interactions to promote hydrogen release is applied to a cation-anion pair in a complex metal hydride. NH4Ca(BH43 is prepared mechanochemically from Ca(BH42 and NH4Cl as well as NH4BH4 following two different protocols, where the synthesis procedures are modified in the latter to solvent-based ball-milling using diethyl ether to maximize the phase yield in chlorine-free samples. During decomposition of NH4Ca(BH43 pure H2 is released, prior to the decomposition of the complex to its constituents. As opposed to a previously reported adduct between Ca(BH42 and NH3BH3, the present complex is described as NH3BH3-stuffed α-Ca(BH42.

  3. Lubrication of sliding bearings for hydropower applications

    OpenAIRE

    McCarthy, Donald

    2005-01-01

    The term "sliding bearing" refers to types of bearing where two conformal surfaces (usually the stationary bearing and a moving shaft) slide relative to one another with load distributed directly across the interface. A suitable lubricant may be employed to reduce the friction between these two surfaces. In "fluid film" bearings, this lubricant builds up a layer of sufficient thickness such that the two surfaces are completely separated. Examples include journal and thrust bearings and shaft ...

  4. Strategy for improved NH2 detection in combustion environments using an Alexandrite laser

    Science.gov (United States)

    Brackmann, Christian; Zhou, Bo; Samuelsson, Per; Alekseev, Vladimir A.; Konnov, Alexander A.; Li, Zhongshan; Aldén, Marcus

    2017-09-01

    A new scheme for NH2 detection by means of laser-induced fluorescence (LIF) with excitation around wavelength 385 nm, accessible using the second harmonic of a solid-state Alexandrite laser, is presented. Detection of NH2 was confirmed by identification of corresponding lines in fluorescence excitation spectra measured in premixed NH3-air flames and on NH2 radicals generated through NH3 photolysis in a nonreactive flow at ambient conditions. Moreover, spectral simulations allow for tentative NH2 line identification. Dispersed fluorescence emission spectra measured in flames and photolysis experiments showed lines attributed to vibrational bands of the NH2 A2A1 ← X2B1 transition but also a continuous structure, which in flame was observed to be dependent on nitrogen added to the fuel, apparently also generated by NH2. A general conclusion was that fluorescence interferences need to be carefully considered for NH2 diagnostics in this spectral region. Excitation for laser irradiances up to 0.2 GW/cm2 did not result in NH2 fluorescence saturation and allowed for efficient utilization of the available laser power without indication of laser-induced photochemistry. Compared with a previously employed excitation/detection scheme for NH2 at around 630 nm, excitation at 385.7 nm showed a factor of 15 higher NH2 signal. The improved signal allowed for single-shot NH2 LIF imaging on centimeter scale in flame with signal-to-noise ratio of 3 for concentrations around 1000 ppm, suggesting a detection limit around 700 ppm. Thus, the presented approach for NH2 detection provides enhanced possibilities for characterization of fuel-nitrogen combustion chemistry.

  5. OHS consultants as facilitators of learning processes in client enterprises

    DEFF Research Database (Denmark)

    Broberg, Ole

    2004-01-01

    in a public institution, and 4) new factory building. The results indicated differences across the OHS consultants studied when it came to the learning aspects of their work practice. In terms of organizational learning, the most com-mon observed effect in the client enterprise was single loop learning......In carrying out consultancy the Danish occupational health services (OHS) are supposed to support and develop the capabilities of enterprises to manage work environment issues. This may be interpreted in a learning perspective: As part of the process consultancy the OHS consultants have to put...... emphasis on initiating learning processes in the client enter-prise in a way that will develop the OHS management capabilities of that enterprise. This presentation is based on a research program focussing on how OHS consultants go about when they are involved in consultancy on technological change...

  6. Young planetary nebula with OH molecules - NGC 6302

    International Nuclear Information System (INIS)

    Payne, H.E.; Phillips, J.A.; Terzian, Y.

    1988-01-01

    The results of a sensitive survey of planetary nebulae in all four ground-state OH lines are reported. The results confirm that evolved planetary nebulas are not OH sources in general. However, one interesting object was not detected: an OH 1612 MHz maser in the young planetary nebula NGC 6302. This nebula may be in a brief evolutionary stage, similar to the young and compact planetary nebula Vy 2-2, where OH has already been detected. In addition, the results of further observations of NGC 6302 are reported, including VLA observations of the 1612 MHz line and continuum emission and detections of rotationally excited OH lines at 5-cm wavelength in absorption. 28 references

  7. Product of autodigestion at Leu63-Ile64 site binds to HIV--1 protease instead of inhibitor Boc-Phe-.PSI.[(S)-CH(OH)CH.sub.2./sub.NH]Phe-Ile-Phe-NH.sub.2./sub..

    Czech Academy of Sciences Publication Activity Database

    Buchtelová, E.; Hašek, Jindřich; Dohnálek, Jan; Petroková, Hana; Dušková, Jarmila; Skálová, Tereza; Brynda, Jiří; Sedláček, Juraj; Hradilek, Martin; Konvalinka, Jan; Tykarska, E.; Jaskolski, M.; Olivi, L.

    2001-01-01

    Roč. 8, 1a (2001), s. 31 ISSN 1211-5894. [Kolokvium Krystalografické společnosti: Struktura 2001. 18.06.2001-22.06.2001, Bedřichov] R&D Projects: GA ČR GA106/99/0557 Subject RIV: CD - Macromolecular Chemistry

  8. Preliminary crystallographic study of native HIV-1 protease inhibited by hydroxyethylamine modified tetrapeptides of Boc-Phe-.psi.[(R/S)-CH(OH)CH2NH]-Phe-Ile-Phe-NH2 type

    Czech Academy of Sciences Publication Activity Database

    Buchtelová, Eva; Hašek, Jindřich; Dohnálek, Jan; Tykarska, E.; Jaskolski, M.; Olivi, L.

    1999-01-01

    Roč. 6, č. 1 (1999), s. 6-7 ISSN 1211-5894 R&D Projects: GA AV ČR IAA4050811; GA ČR GV203/98/K023 Institutional research plan: CEZ:AV0Z4050913 Keywords : HIV protease * hydroxyethylamine inhibitors * crystallization Subject RIV: CD - Macromolecular Chemistry

  9. Interactions between kaolinite Al−OH surface and sodium hexametaphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yonghua, E-mail: hyh19891102@163.com [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Liu, Wenli; Zhou, Jia [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chen, Jianhua [College of Resources and Metallurgy, Guangxi University, Nanning 530004 (China)

    2016-11-30

    Highlights: • Sodium hexametaphosphate (NaHMP) can adsorb on kaolinite Al−OH terminated (001) surface easily. • The oxygen atoms of hexametaphosphate form strong hydrogen bonds with the hydrogen atoms of kaolinite Al−OH surface. • The electrostatic force is the main interaction between NaHMP and Al−OH surface. • The linear hexaphosphate −[PO{sub 3}]{sub m}− chains adsorb stably than −[HPO{sub 3}]{sub m}− chains. - Abstract: To investigate the dispersion mechanism of sodium hexametaphosphate on kaolinite particles, we simulated the interaction between linear polyphosphate chains and kaolinite Al−OH terminated surface by molecular dynamics, as well as the interaction between the [HPO{sub 4}]{sup 2−} anion and kaolinite Al−OH surface by density functional theory (DFT). The calculated results demonstrate that hexametaphosphate can be adsorbed by the kaolinite Al−OH surface. The oxygen atoms of hexametaphosphate anions may receive many electrons from the Al−OH surface and form hydrogen bonds with the hydrogen atoms of surface hydroxyl groups. Moreover, electrostatic force dominates the interactions between hexametaphosphate anions and kaolinite Al−OH surface. Therefore, after the adsorption of hexametaphosphate on kaolinite Al−OH surface, the kaolinite particles carry more negative charge and the electrostatic repulsion between particles increases. In addition, the adsorption of −[PO{sub 3}]{sub m}− species on the Al−OH surface should be more stable than the adsorption of −[HPO{sub 3}]{sub m}− species.

  10. The Weight-Bearing Shoulder.

    Science.gov (United States)

    Patel, Ronak M; Gelber, Jonathan D; Schickendantz, Mark S

    2018-01-01

    The shoulder achieves a wide spectrum of motion, and in a subset of patients, including those who use manual wheelchairs and upper extremity walking aids, the shoulder also serves as the primary weight-bearing joint. Because the weight-bearing shoulder is subject to considerable joint reaction forces and overuse, a broad spectrum of pathology can affect the joint. The combination of muscle imbalance and repetitive trauma presents most commonly as subacromial impingement syndrome but can progress to other pathology. Patients with high-level spinal cord injury, leading to quadriplegia and motor deficits, have an increased incidence of shoulder pain. Understanding the needs of patients who use manual wheelchairs or walking aids can help the physician to better comprehend the pathology of and better manage the weight-bearing shoulder.

  11. AMT1;1 transgenic rice plants with enhanced NH4 + permeability show superior growth and higher yield under optimal and suboptimal NH4 + conditions

    Science.gov (United States)

    Rothstein, Steven J.

    2014-01-01

    The major source of nitrogen for rice (Oryza sativa L.) is ammonium (NH4 +). The NH4 + uptake of roots is mainly governed by membrane transporters, with OsAMT1;1 being a prominent member of the OsAMT1 gene family that is known to be involved in NH4 + transport in rice plants. However, little is known about its involvement in NH4 + uptake in rice roots and subsequent effects on NH4 + assimilation. This study shows that OsAMT1;1 is a constitutively expressed, nitrogen-responsive gene, and its protein product is localized in the plasma membrane. Its expression level is under the control of circadian rhythm. Transgenic rice lines (L-2 and L-3) overexpressing the OsAMT1;1 gene had the same root structure as the wild type (WT). However, they had 2-fold greater NH4 + permeability than the WT, whereas OsAMT1;1 gene expression was 20-fold higher than in the WT. Analogous to the expression, transgenic lines had a higher NH4 + content in the shoots and roots than the WT. Direct NH4 + fluxes in the xylem showed that the transgenic lines had significantly greater uptake rates than the WT. Higher NH4 + contents also promoted higher expression levels of genes in the nitrogen assimilation pathway, resulting in greater nitrogen assimilates, chlorophyll, starch, sugars, and grain yield in transgenic lines than in the WT under suboptimal and optimal nitrogen conditions. OsAMT1;1 also enhanced overall plant growth, especially under suboptimal NH4 + levels. These results suggest that OsAMT1;1 has the potential for improving nitrogen use efficiency, plant growth, and grain yield under both suboptimal and optimal nitrogen fertilizer conditions. PMID:24420570

  12. Crystal structure and charge density analysis of Li2NH by synchrotron X-ray diffraction

    International Nuclear Information System (INIS)

    Noritake, T.; Nozaki, H.; Aoki, M.; Towata, S.; Kitahara, G.; Nakamori, Y.; Orimo, S.

    2005-01-01

    Complex hydrides, such as lithium amide (LiNH 2 ) and lithium imide (Li 2 NH), have recently been noticed as one of the most promising materials for reversible hydrogen storage. In this paper, we reveal the bonding nature of hydrogen in Li 2 NH crystal by synchrotron powder X-ray diffraction measurement at room temperature. The crystal structure was refined by Rietveld method and the charge density distribution was analyzed by maximum entropy method (MEM). The Li 2 NH crystal is anti-fluorite type structure (space group Fm3-bar m) consisting of Li and NH. Hydrogen atom occupies randomly the 48h (Wyckoff notation) sites around N atom. The refined lattice constant is a=5.0742(2)A. The charge density distribution around NH anion in Li 2 NH is almost spherical. The number of electrons within the sphere around the Li and NH is estimated from the obtained charge density distribution. As the result, the ionic charge is expressed as [Li 0.99+ ] 2 [NH] 1.21- . Therefore, it is confirmed experimentally that Li 2 NH is ionically bonded

  13. Wave Journal Bearing. Part 1: Analysis

    Science.gov (United States)

    Dimofte, Florin

    1995-01-01

    A wave journal bearing concept features a waved inner bearing diameter of the non-rotating bearing side and it is an alternative to the plain journal bearing. The wave journal bearing has a significantly increased load capacity in comparison to the plain journal bearing operating at the same eccentricity. It also offers greater stability than the plain circular bearing under all operating conditions. The wave bearing's design is relatively simple and allows the shaft to rotate in either direction. Three wave bearings are sensitive to the direction of an applied stationary side load. Increasing the number of waves reduces the wave bearing's sensitivity to the direction of the applied load relative to the wave. However, the range in which the bearing performance can be varied decreases as the number of waves increases. Therefore, both the number and the amplitude of the waves must be properly selected to optimize the wave bearing design for a specific application. It is concluded that the stiffness of an air journal bearing, due to hydrodynamic effect, could be doubled and made to run stably by using a six or eight wave geometry with a wave amplitude approximately half of the bearing radial clearance.

  14. Analysis of NSTX Upgrade OH Magnet and Center Stack

    Energy Technology Data Exchange (ETDEWEB)

    A. Zolfaghari, P. Titus, J. Chrzanowski, A. Salehzadeh, F. Dahlgren

    2010-11-30

    The new ohmic heating (OH) coil and center stack for the National Spherical Torus Experiment (NSTX) upgrade are required to meet cooling and structural requirements for operation at the enhanced 1 Tesla toroidal field and 2 MA plasma current. The OH coil is designed to be cooled in the time between discharges by water flowing in the center of the coil conductor. We performed resistive heating and thermal hydraulic analyses to optimize coolant channel size to keep the coil temperature below 100 C and meet the required 20 minute cooling time. Coupled electromagnetic, thermal and structural FEA analyses were performed to determine if the OH coil meets the requirements of the structural design criteria. Structural response of the OH coil to its self-field and the field from other coils was analyzed. A model was developed to analyze the thermal and electromagnetic interaction of centerstack components such as the OH coil, TF inner legs and the Bellville washer preload mechanism. Torsional loads from the TF interaction with the OH and poloidal fields are transferred through the TF flag extensions via a torque transfer coupling to the rest of the tokamak structure. A 3D FEA analysis was performed to qualify this design. The results of these analyses, which will be presented in this paper, have led to the design of OH coil and centerstack components that meet the requirements of the NSTX-upgrade structural design criteria.

  15. Crystal structure of hexagonal RE(CO{sub 3})OH

    Energy Technology Data Exchange (ETDEWEB)

    Michiba, Kiyonori; Tahara, Takeshi; Nakai, Izumi [Tokyo Univ. of Science, Shinjuku (Japan). Faculty of Science; Miyawaki, Ritsuro; Matsubara, Satoshi [National Museum of Nature and Science, Tokyo (Japan). Dept. of Geology and Paleontology

    2011-07-01

    Hexagonal rare earth carbonate hydroxides, RE(CO{sub 3})OH, where RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er, were hydrothermally synthesized from formic acid and hydroxide gels of rare earth elements. The crystals exhibited bicephalous hexagonal prisms with lengths of several tens of micrometers. The crystal structures of a series of hexagonal RE(CO{sub 3})OH were solved using the single crystal CCD-XRD intensity data sets. The space groups of the synthetic hexagonal RE(CO{sub 3})OH crystals are all P- anti 6. The present study has cast doubt upon the space group P- anti 62c previously reported for the natural Ce(CO{sub 3})OH, hydroxylbastnaesite-(Ce). The cell parameters decreased linearly with decreases in the ionic radii of the rare earth elements. La(CO{sub 3})OH showed the largest unit cell (a = 12.6752(6), c = 10.0806(10) A), while Er(CO{sub 3})OH showed the smallest (a = 11.8977(4), c = 9.6978(8) A). The rare earth atoms are in ninefold coordination with oxygen atoms to form a tricapped trigonal prism. The structure consists of layers of {sup 2}{infinity}[(OH)RE{sub 3/3}]{sup 2+} ions linked by carbonate ions. Raman spectra indicate the presence of carbonate and hydroxide groups. An evolutionary shift was observed from La to Er towards higher frequency, which was associated with a decreasing RE-O bond length. (orig.)

  16. Reaction of atomic bromine with acetylene and loss rate of atmospheric acetylene due to reaction with OH, Cl, O, and Br

    Science.gov (United States)

    Payne, W. A.; Nava, D. F.; Brunning, J.; Stief, L. J.

    1986-01-01

    The first-order, diffusion, and bimolecular rate constants for the reaction Br + C2H2 yields C2H3Br are evaluated. The rate constants are measured at 210, 248, 298, and 393 K and at pressures between 15-100 torr Ar using flash photolysis combined with time-resolved detection of atomic bromine via Br resonance radiation. It is observed that the reaction is not affected by pressure or temperature and the bimolecular constant = (4.0 + or - 0.8) x 10 to the -15th cu cm/sec with an error of two standard deviations. The C2H2 + Br reaction rates are compared with reactions of C2H2 with Cl, OH, NH2, and H. The loss rates for atmospheric C2H2 for reactions with OH, Cl, O, and Br are calculated as a function of altitude.

  17. Parallel operation of NH3 screw compressors - the optimum way

    Science.gov (United States)

    Pijnenburg, B.; Ritmann, J.

    2015-08-01

    The use of more smaller industrial NH3 screw compressors operating in parallel seems to offer the optimum way when it comes to fulfilling maximum part load efficiency, increased redundancy and other highly requested features in the industrial refrigeration industry today. Parallel operation in an optimum way can be selected to secure continuous operation and can in most applications be configured to ensure lower overall operating economy. New compressors are developed to meet requirements for flexibility in operation and are controlled in an intelligent way. The intelligent control system keeps focus on all external demands, but yet striving to offer always the lowest possible absorbed power, including in future scenarios with connection to smart grid.

  18. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-01-01

    © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

  19. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  20. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  1. BEAR AT THE BACK DOOR

    African Journals Online (AJOL)

    BEAR AT THE BACK DOOR. Deur generaal sir Walter Walker KCB, CBE,. D80. 8andton. Uitgegee deur Valiant Publis- hers. Verskyningsdatum Julie 1978. Prys R10.) Hierdie boek is 'n uitstekende aktuele geskrif ook. Suidelike Afrika se politieke en militere aspekte wat deur 'n a/gehele buitestaander nl 'n Britse. Generaal ...

  2. [UO2(NH3)5]Br2·NH3: synthesis, crystal structure, and speciation in liquid ammonia solution by first-principles molecular dynamics simulations.

    Science.gov (United States)

    Woidy, Patrick; Bühl, Michael; Kraus, Florian

    2015-04-28

    Pentaammine dioxido uranium(VI) dibromide ammonia (1/1), [UO2(NH3)5]Br2·NH3, was synthesized in the form of yellow crystals by the reaction of uranyl bromide, UO2Br2, with dry liquid ammonia. The compound crystallizes orthorhombic in space group Cmcm and is isotypic to [UO2(NH3)5]Cl2·NH3 with a = 13.2499(2), b = 10.5536(1), c = 8.9126(1) Å, V = 1246.29(3) Å(3) and Z = 4 at 123 K. The UO2(2+) cation is coordinated by five ammine ligands and the coordination polyhedron can be best described as pentagonal bipyramid. Car-Parrinello molecular dynamics simulations are reported for [UO2(NH3)5](2+) in the gas phase and in liquid NH3 solution (using the BLYP density functional). According to free-energy simulations, solvation by ammonia has only a small effect on the uranyl-NH3 bond strength.

  3. CO2 Absorption and Magnesium Carbonate Precipitation in MgCl2–NH3–NH4Cl Solutions: Implications for Carbon Capture and Storage

    Directory of Open Access Journals (Sweden)

    Chen Zhu

    2017-09-01

    Full Text Available CO2 absorption and carbonate precipitation are the two core processes controlling the reaction rate and path of CO2 mineral sequestration. Whereas previous studies have focused on testing reactive crystallization and precipitation kinetics, much less attention has been paid to absorption, the key process determining the removal efficiency of CO2. In this study, adopting a novel wetted wall column reactor, we systematically explore the rates and mechanisms of carbon transformation from CO2 gas to carbonates in MgCl2–NH3–NH4Cl solutions. We find that reactive diffusion in liquid film of the wetted wall column is the rate-limiting step of CO2 absorption when proceeding chiefly through interactions between CO2(aq and NH3(aq. We further quantified the reaction kinetic constant of the CO2–NH3 reaction. Our results indicate that higher initial concentration of NH4Cl ( ≥ 2 mol · L − 1 leads to the precipitation of roguinite [ ( NH 4 2 Mg ( CO 3 2 · 4 H 2 O ], while nesquehonite appears to be the dominant Mg-carbonate without NH4Cl addition. We also noticed dypingite formation via phase transformation in hot water. This study provides new insight into the reaction kinetics of CO2 mineral carbonation that indicates the potential of this technique for future application to industrial-scale CO2 sequestration.

  4. Atmospheric chemistry of CF3CH2CH2OH

    DEFF Research Database (Denmark)

    Hurley, Michael D.; Misner, Jessica A.; Ball, James C.

    2005-01-01

    Relative rate techniques were used to study the kinetics of the reactions of Cl atoms and OH radicals with CF3CH2C(O)H and CF3CH2CH2OH in 700 Torr of N-2 or air diluent at 296 2 K. The rate constants determined were k(Cl+CF3CH2C(O)H) = (1.81 +/- 0.27) x 10(-11), k(OH+CF3CH2C(O)H) = (2.57 +/- 0.44...

  5. Climate Change, Polar Bears and their management

    OpenAIRE

    Derenchenko, Liza

    2010-01-01

    This is a literature study of polar bears in the context of climate change: what kind of creatures are polar bears, what are the main interpretations of current climate change, how might the polar bear adapt to these changes (feeding strategies) and how are the bears being managed (hunting)? These are relevant questions , since climate change is on the agenda, and polar bears being the apex predators of the Arctic are a key representation of the wildlife there. The third element of polar bear...

  6. Moving to Sustainable Metals. Multifunctional Ligands in Catalytic, Outer Sphere C-H, N-H and O-H Activation

    Energy Technology Data Exchange (ETDEWEB)

    Crabtree, Robert [Yale Univ., New Haven, CT (United States)

    2015-03-03

    Much of our work during this grant period has emphasized green chemistry and sustainability. For example, we were able to convert glycerine, a waste byproduct of biodiesel production, into lactic acid, a compound with numerous applications, notably in the food and cosmetics industry, as well as being a source material for a biodegradable plastic. This work required a catalyst, that ceases to work after a certain lapse of time. We were able to identify the way in which this deactivation occurs by identifying some of the metal catalyst deactivation products. These proved to be multimetallic clusters containing up to six metals and up to 14 hydrogen atoms. Both the catalytic reaction itself and the deactivation structures are novel and unexpected. We have previously proposed that nitrogen heterocycles could be good energy carriers in a low CO2 future world. In another part of our study, we found catalysts for introduction of hydrogen, an energy carrier that is hard to store, into nitrogen heterocycles. The mechanism of this process proved to be unusual in that the catalyst transfers the H2 to the heterocycle in the form of H+ and H-, first transferring the H+ and only then the H-. In a third area of study, some of our compounds, originally prepared for DOE catalysis purposes, also proved useful in hydrocarbon oxidation and in water oxidation. The latter is important in solar-to-fuel work, because, by analogy with natural photosynthesis, the goal of the Yale Solar Group of four PIs is to convert sunlight to hydrogen and oxygen, which requires water splitting catalysts. The catalysts that proved useful mediate the latter reaction: water oxidation to oxygen. In a more technical study, we developed methods for distinguishing the case where catalysis is mediated by a soluble catalyst from cases where catalysis arises from a deposit of finely divided solid. One particular application involved electrocatalysis, where catalysis is driven by application of a voltage to electrodes dipped in the reactant mixture. We measured the mass increase of an electrode as material is deposited, and were able to see how this process is affected by the voltage supplied to the electrode. Our work continues to be well cited and we often receive requests for information or samples from fellow researchers.

  7. NH and OH Concentration Profiles in a Stoichiometric CH4/N2O Flame by Laser Excited Fluorescence and Absorption Techniques.

    Science.gov (United States)

    1982-10-01

    Fundamantal Data, J. Quant. Spectrosc. Radiat. Transfer, Vol. 2, p. 97, 1962. 33 REFERENCES 23. Anderson, W.R., Decker, L.J. and Kotlar, A.J...used? (Information source, design data or procedure, management procedure, source of ideas, etc.) 4. Has the information in this report led to any

  8. PEMBUATAN ASAM OKSALAT DARI SEKAM PADI DENGAN HIDROLISIS BERKATALISATOR NaOH DAN Ca(OH2

    Directory of Open Access Journals (Sweden)

    Primata Mardina

    2014-03-01

    Full Text Available Rice husk is a major by-product of the rice milling industries. Rice husk  is one of the most common  lignocellulosic materials those can be converted to oxalic acid by alkaline hydrolysis. This research investigated the effect of  the alkaline catalysts at specified temperature and reaction time on the efficiency of  process and  yield of oxalic acid. Oxalic acid was produced by four processes; alkaline hydrolysis, precipitation, acidification, and crystalization. Washed and dryed rice husk was crushed  to obtain 0.25 mm diameterl particles. The main process was performed by dissolving and hydrolyzing 125 grams of rice husk in 500 mL of 3.5 N NaOH and Ca(OH2. Rice husk, which hydrolyzed by NaOH, was  precipated with CaCl2 before acidification, whereas rice husk, which hydrolyzed by Ca(OH2 directly acidified by sulphuric acid without precipitation process. Furthermore, water in acidified solution was evaporated to obtain crystal of oxalic acid. The result showed the alkaline catalyst Ca(OH2 was more eficient than NaOH for hydrolysis. It omitted precipitation process. The highest yield of oxalic acid which produced by Ca(OH2 catalyzed hydrolysis was 2.232%  at 60oC for 60 minutes.

  9. Pembuatan Arang Aktif dari Sabut Kelapa Sawit dengan Bahan Pengaktif Nh4hco3 dan (Nh4)2c03 Dosis Rendah 1)

    OpenAIRE

    Pari, Gustan; Sailah, Ilah

    2001-01-01

    This report deals with experimental study on the utilization of palm-tree bast as raw material for activated charcoal. In this regard, the main aim was to study the effect of concentrations of vaporized NH4HCO3and (NH4)2C03 solutions as activating agents (in persentages) on properties of activated charcoal, and to evaluate its use for purifying ground waler In this regard. the vapors might consist of NH3, CO2, and H2O. The manufacture of activated charcoal involved two consecutive stages, i....

  10. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  11. The Transition from Hydrogen Bonding to Ionization in (HCI)n(NH3)n and (HCI)n(H2O)n Clusters: Consequences for Anharmonic Vibrational Spectroscopy

    Science.gov (United States)

    Chaban, Galina M.; Gerber, R. Benny; Janda, Kenneth C.; Kwak, Dochan (Technical Monitor)

    2001-01-01

    Anharmonic vibrational frequencies and intensities are calculated for 1:1 and 2:2 (HCl)(sub n)(NH3)(sub n) and (HCl)(sub n)(H2O)(sub n) complexes, employing the correlation-corrected vibrational self-consistent field method with ab initio potential surfaces at the MP2/TZP computational level. In this method, the anharmonic coupling between all vibrational modes is included, which is found to be important for the systems studied. For the 4:4 (HCl)(sub n)(H2O)(sub n) complex, the vibrational spectra are calculated at the harmonic level, and anharmonic effects are estimated. Just as the (HCl)(sub n)(NH3)(sub n) structure switches from hydrogen-bonded to ionic for n=2, the (HCl)(sub n)(H2O)(sub n) switches to ionic structure for n=4. For (HCl)2(H2O)2, the lowest energy structure corresponds to the hydrogen-bonded form. However, configurations of the ionic form are separated from this minimum by a barrier of less than an O-H stretching quantum. This suggests the possibility of experiments on ionization dynamics using infrared excitation of the hydrogen-bonded form. The strong cooperative effects on the hydrogen bonding, and concomitant transition to ionic bonding, makes an accurate estimate of the large anharmonicity crucial for understanding the infrared spectra of these systems. The anharmonicity is typically of the order of several hundred wave numbers for the proton stretching motions involved in hydrogen or ionic bonding, and can also be quite large for the intramolecular modes. In addition, the large cooperative effects in the 2:2 and higher order (HCl(sub n)(H2O)(sub n) complexes may have interesting implications for solvation of hydrogen halides at ice surfaces.

  12. Dehydriding reaction of Mg(NH2)2-LiH system under hydrogen pressure

    International Nuclear Information System (INIS)

    Aoki, M.; Noritake, T.; Kitahara, G.; Nakamori, Y.; Towata, S.; Orimo, S.

    2007-01-01

    The dehydriding and structural properties of the 3Mg(NH 2 ) 2 + 12LiH system under hydrogen pressure were investigated using the pressure-composition (p-c) isotherm measurement and X-ray diffraction (XRD) analysis. Two distinct regions, a plateau region and a sloping region, can be seen on the p-c isotherms and the amount of the desorbed hydrogen at 523 K was 4.9 mass%. The enthalpy of hydrogenation calculated using a van't Hoff plot was -46 kJ/mol H 2 . The dehydriding reaction was proposed for the 3Mg(NH 2 ) 2 + 12LiH system based on the obtained p-c isotherms and XRD profiles and chemical valences of Li, Mg, N, and H. In the plateau region on the p-c isotherm, Mg(NH 2 ) 2 , Li 4 Mg 3 (NH 2 ) 2 (NH) 4 (tetragonal), and LiH phases coexist and the molar ratio of the Li 4 Mg 3 (NH 2 ) 2 (NH) 4 phase increases (while those of Mg(NH 2 ) 2 and LiH phases decrease) with the amount of the desorbed hydrogen. On the other hand, the mixture of Li 4+x Mg 3 (NH 2 ) 2-x (NH) 4+x + (8-x)LiH (0 ≤ x ≤ 2) is formed and the lattice volume of the Li 4+x Mg 3 (NH 2 ) 2-x (NH) 4+x phase continuously increases with the amount of the desorbed hydrogen in the sloping region on the p-c isotherm

  13. The structure of NH4F as determined by neutron and X-ray diffraction

    NARCIS (Netherlands)

    Adrian, H.W.W.; Feil, D.

    1969-01-01

    Neutron and X-ray intensities of NH4F were measured at -196°C and -155°C respectively. The wurtzite type structure and space group P63mc were confirmed. The displacement of the two h.c.p. sublattices, formed by each of the F-- and NH+4- ions, is such that all bond-distances are equivalent. The N-H

  14. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  15. Deactivation of Highly Vibrationally Excited OH by O Atoms

    Science.gov (United States)

    Copeland, R. A.; Smith, G. P.; Mlynczak, M. M.; Kalogerakis, K. S.

    2006-12-01

    The hydroxyl radical is a key player in the chemistry and energetics of the middle terrestrial atmosphere, and several studies have investigated energy transfer processes between OH(υ) and atmospheric molecules. Nevertheless, a gap exists in our understanding of its interaction with oxygen atoms. Oxygen atoms are present at about 10% of the oxygen molecule concentration at ~95 km and about 1% at 88 km, so if their rate constant is significantly faster than that of O2 and N2, they will strongly influence the intensity and the vibrational distribution extracted from the OH(υ) emission. We report laboratory measurements of the total removal rate constants of OH(υ = 8, 9) by O(3 P) atoms and preliminary measurements on CO2. These measurements are required so that we can quantify the importance of these collisional processes in the modeling of atmospheric OH emissions and evaluate the chemical heating rate from measurements by the SABER instrument aboard the TIMED satellite. In the experiments, we generate O(3P) and OH(υ) by photodissociation of ozone at 250 nm in a mixture of ozone, nitrogen, hydrogen. The highly excited vibrational levels OH(υ = 7-9) are produced in the reaction of H atoms with ozone that has not been photodissociated. We monitor the temporal evolution of the OH(υ = 8 and 9) population by laser excitation via the \\it B3Σ_u- \\textendash \\it X3Σ_g- (0,9) and (0,8) transitions near 237 nm and 226 nm, respectively, and subsequent detection of visible fluorescence emitted from the \\it B3Σ_u^{- } \\textendash \\it A3Σ_u+ band, an approach developed previously in our laboratory [1]. By controlling the initial conditions of the experiments, we can extract the rate coefficient for OH removal by O atoms in the system. For direct analysis of the OH signal rise to yield accurate rate coefficients an extremely good signal-to-noise-ratio is required. However, a preferred approach involves comparison of the OH signal relative intensity changes when

  16. Antitumor and other effects of 24R,25-dihydroxycholecalciferol in Lewis lung carcinoma causing abnormal calcium metabolism in tumor-bearing mice.

    Science.gov (United States)

    Maeda, Y; Yamato, H; Hirai, T; Kobori, N; Fujii, T; Kobayashi, Y; Saitoh, K; Inoguchi, E; Hakozaki, M; Iijima, H

    1988-01-01

    Lewis lung carcinoma was found to cause hypercalcemia in tumor-bearing mice. 24R,25(OH)2D3 (K-DR, prepared by Kureha Chemical Ind.) significantly prolonged the survival time of mice with Lewis lung carcinoma. K-DR exhibited an antimetastatic effect on Lewis lung carcinoma, and also had an analgesic effect in mice with Lewis lung carcinoma.

  17. Determination of the hydrogen positions in the novel barium boroarsenate Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] by combined single crystal X-ray and powder neutron investigations

    Energy Technology Data Exchange (ETDEWEB)

    Lieb, Alexandra [School of Chemistry, University of Southampton (United Kingdom); Fakultaet fuer Verfahrens- und Systemtechnik, Lehrstuhl fuer Technische Chemie, Otto-von-Guericke-Universitaet, Magdeburg (Germany); Weller, Mark T. [School of Chemistry, University of Southampton (United Kingdom); Department of Chemistry, University of Bath (United Kingdom)

    2017-11-17

    The boroarsenate Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was obtained by the reaction of NH{sub 4}H{sub 2}AsO{sub 4}, B(OH){sub 3} and BaBr{sub 2}.2H{sub 2}O in the melt. Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was obtained as thin colorless needles, together with spherical crystals of BAsO{sub 4} as by-product, grown on a pellet of Ba[BAsO{sub 5}]. The products could be separated mechanically. For neutron scattering experiments a sample was prepared with {sup 11}B(OH){sub 3} as a starting material. The crystal structure of Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was determined by single-crystal X-ray diffraction and exhibits a layer structure with an unprecedented layer topology. The exact positions of the hydrogen atoms were determined using combined single-crystal X-ray and powder neutron diffraction investigations. Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was further characterized by IR spectroscopy and EDX analysis. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. NH4SH and cloud cover in the atmospheres of the giant planets

    Science.gov (United States)

    Ibragimov, K. Iu.; Solodovnik, A. A.

    1991-02-01

    The probability of the formation of NH4SH and (NH4)2S is examined on the basis of the Le Chatelier principle. It is shown that it is very doubtful if NH4SH can be created in the atmospheres of the giant planets in quantities sufficient for cloud formation. Thus (NH4)2S is considered as a more likely candidate for cloud formation in the atmospheres of these planets, inasmuch as the conditions for its production there are more favorable.

  19. Investigation on thermal evaporated CH3NH3PbI3 thin films

    International Nuclear Information System (INIS)

    Li, Youzhen; Xu, Xuemei; Yang, Junliang; Wang, Chenggong; Wang, Congcong; Gao, Yongli; Xie, Fangyan

    2015-01-01

    CH 3 NH 3 I, PbI 2 and CH 3 NH 3 PbI 3 films were fabricated by evaporation and characterized with X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD). The XPS results indicate that the PbI 2 and CH 3 NH 3 PbI 3 films are more uniform and stable than the CH 3 NH 3 I film. The atomic ratio of the CH 3 NH 3 I, PbI 2 and CH 3 NH 3 PbI 3 films are C:N:I=1.00:1.01:0.70, Pb:I= 1.00:1.91 and C: N: Pb: I = 1.29:1.07:1.00:2.94, respectively. The atomic ratio of CH 3 NH 3 PbI 3 is very close to that of the ideal perovskite. Small angle x-ray diffraction results demonstrate that the as evaporated CH 3 NH 3 PbI 3 film is crystalline. The valence band maximum (VBM) and work function (WF) of the CH 3 NH 3 PbI 3 film are about 0.85eV and 4.86eV, respectively

  20. Dynamics of gas-thrust bearings

    Science.gov (United States)

    Stiffler, A. K.; Tapia, R. R.

    1978-01-01

    Computer program calculates load coefficients, up to third harmonic, for hydrostatic gas thrust bearings. Program is useful in identification of industrial situations where gas-thrust bearings have potential applications.

  1. Rolling Element Bearing Stiffness Matrix Determination (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y.; Parker, R.

    2014-01-01

    Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

  2. Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

    Science.gov (United States)

    Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

    2012-01-01

    We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

  3. Effect NaOH Concentration on Bagasse Ash Based Geopolymerization

    Directory of Open Access Journals (Sweden)

    Saloma

    2016-01-01

    Full Text Available Geopolymer is a natural adhesive material which can be developed as a substitute for cement. The natural ingredients which want to use should contain silica and alumina. This paper uses bagasse ash as a basic material of mortar geopolymer. As an adhesive, the bagasse ash should be mixed with water and another activator alkali such as sodium hydroxide (NaOH and sodium silicate (Na2SiO3. The NaOHs molarity variation are 8, 10, 12, 14 and 16 M with Na2SiO3/NaOH = 1,0 sand/bagasse ash = 2,75 and activator/bagasse ash = 0,42. This research use 50 × 50 × 50 mm cube sized specimen and conduct a compressive strength test with 3, 7, 14, 21 and 28 days. The fresh mortar test result showed that the use of NaOHs molarity variation influences the slump value and time setting. The bigger NaOH molarity variation that been used, the smaller slump value. But, the time setting is increased. While the result for density and compressive strength shown that the bigger NaOH molarity variation, the bigger density and the compressive strength. Maximum compressive strength resulted from the mixture of mortar geopolymer with 16 M concentration.

  4. Catalytic Silylation of N2and Synthesis of NH3and N2H4by Net Hydrogen Atom Transfer Reactions Using a Chromium P4Macrocycle.

    Science.gov (United States)

    Kendall, Alexander J; Johnson, Samantha I; Bullock, R Morris; Mock, Michael T

    2018-02-21

    We report the first discrete molecular Cr-based catalysts for the reduction of N 2 . This study is focused on the reactivity of the Cr-N 2 complex, trans-[Cr(N 2 ) 2 (P Ph 4 N Bn 4 )] (P 4 Cr(N 2 ) 2 ), bearing a 16-membered tetraphosphine macrocycle. The architecture of the [16]-P Ph 4 N Bn 4 ligand is critical to preserve the structural integrity of the catalyst. P 4 Cr(N 2 ) 2 was found to mediate the reduction of N 2 at room temperature and 1 atm pressure by three complementary reaction pathways: (1) Cr-catalyzed reduction of N 2 to N(SiMe 3 ) 3 by Na and Me 3 SiCl, affording up to 34 equiv N(SiMe 3 ) 3 ; (2) stoichiometric reduction of N 2 by protons and electrons (for example, the reaction of cobaltocene and collidinium triflate at room temperature afforded 1.9 equiv of NH 3 , or at -78 °C afforded a mixture of NH 3 and N 2 H 4 ); and (3) the first example of NH 3 formation from the reaction of a terminally bound N 2 ligand with a traditional H atom source, TEMPOH (2,2,6,6-tetramethylpiperidine-1-ol). We found that trans-[Cr( 15 N 2 ) 2 (P Ph 4 N Bn 4 )] reacts with excess TEMPOH to afford 1.4 equiv of 15 NH 3 . Isotopic labeling studies using TEMPOD afforded ND 3 as the product of N 2 reduction, confirming that the H atoms are provided by TEMPOH.

  5. Mercury in polar bears from Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Lentfer, J.W.; Galster, W.A.

    1987-04-01

    Alaskan polar bear (Ursus maritimus) muscle and liver samples collected in 1972 were analyzed for total mercury. Bears north of Alaska had more mercury than bears west of Alaska. The only difference between young and adult animals was in the northern area where adults had more mercury in liver tissue than young animals. Levels were probably not high enough to be a serious threat to bears.

  6. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  7. Study of the thermodynamic properties of the metallic compounds Sr(NH{sub 3}){sub 6} and Li(NH{sub 3}){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Medouer, Hadria [L.E.P.C.M, Departement de physique, Faculte des sciences, Universite de Batna, B.P. C2045, Poste Hadj Lakhdar, Batna 05011 (Algeria); Messaadi, Saci [L.E.P.C.M, Departement de physique, Faculte des sciences, Universite de Batna, B.P. C2045, Poste Hadj Lakhdar, Batna 05011 (Algeria)], E-mail: messaadi_saci@yahoo.fr; Aiadi, Kamel Eddine [Departement de physique, Faculte des sciences et sciences de l' ingenieur, Universite de Ouargla (Algeria)

    2009-03-20

    The metallic compounds Sr(NH{sub 3}){sub 6} and Li(NH{sub 3}){sub 4} are prepared in vacuum within cells of quartz. The non-reproducibility of Jacobs' measurements of the heat capacity at high temperature of the compound Sr(NH{sub 3}){sub 6} led us to reconsider the thermal studies. Our measurements by differential thermal analysis (D.T.A.) were obtained by the analysis of the phase shift between the piloting and the differential signals. The metallic compound Li(NH{sub 3}){sub 4} was also examined by the mean of D.T.A. A detailed study has been carried out in a range of temperature 25-90 K, where the results obtained shows a second-order transition at 23 K, which can be compared with these observed in the case of deutered compound.

  8. A multiferroic material [NH2-CH+-NH2]Co(HCOO3 of metal-organic frameworks with weak ferromagnetism and dielectric relaxation

    Directory of Open Access Journals (Sweden)

    Jiangqi Luo

    2017-10-01

    Full Text Available In order to seek for the single-phase multiferroic metal-organic frameworks (MOFs materials, we prepared a multiferroic material [NH2-CH+-NH2]Co(HCOO3 (FMDCo by solvothermal method. We found that it had weak ferromagnetism below 12.5 K with the coercive fields (Hc of 560 Oe, remnant magnetization (Mr of 7.67 emu/g and saturation magnetization (Ms of 10.3 emu/g and exhibited obvious dielectric relaxation. The octahedral metal ions (Co2+ were linked by formate (HCOO- ligands. The AmineH+ cation (NH2-CH+-NH2 were located within the cube-like cavities of the framework and formed extensive hydrogen bonds with the framework. This improved the phase transition temperature and thermal stability. This finding helps to understand the nature of magnetic and electric ordering in the MOFs.

  9. Experimental studies of the formation of cluster ions formed by corona discharge in an atmosphere containing SO2, NH3, and H2O

    DEFF Research Database (Denmark)

    Hvelplund, Preben; Pedersen, Jens Olaf Pepke; Støchkel, Kristian

    2013-01-01

    Abstract We report on studies of ion-induced nucleation in a corona discharge taking place in an atmosphere containing SO2, NH3, and H2O at standard temperature and pressure. Positive ions such as H3O+(H2O)n, NH4+(H2O)n, and H+(H2SO4)(H2O)n and negative ions such as HSO5-(H2O)n, SO4-(H2O)n, HSO4-(H......5-, which has been observed in many studies, in our experiments is contaminated by O2-(HNO3)(H2O) ions, and this may also have been the case in other experiments. Finally an ion with m/z = 232 (where m is the cluster mass in amu and z is the charge state), capable of attaching H2O...

  10. Thin film superconductor magnetic bearings

    Science.gov (United States)

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  11. Passive Thermal Management of Foil Bearings

    Science.gov (United States)

    Bruckner, Robert J. (Inventor)

    2015-01-01

    Systems and methods for passive thermal management of foil bearing systems are disclosed herein. The flow of the hydrodynamic film across the surface of bearing compliant foils may be disrupted to provide passive cooling and to improve the performance and reliability of the foil bearing system.

  12. 49 CFR 229.64 - Plain bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

  13. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  14. Hydrodynamic squeeze-film bearings for gyroscopes

    Science.gov (United States)

    Chiang, T.; Smith, R. L.

    1970-01-01

    Experimental tests are conducted on squeeze-film bearings by applying electricity to piezoelectric ceramics, causing vibrations at thousands or millions of Hz that are amplified and transmitted to the bearing. Rotor operation through 24,000 rpm without whirl instability proved bearing ability to support rotor weight without hydrodynamic action.

  15. 14 CFR 23.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

  16. 14 CFR 25.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  17. 14 CFR 27.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  18. 14 CFR 29.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  19. Fractal analysis of polar bear hairs

    Directory of Open Access Journals (Sweden)

    Wang Qing-Li

    2015-01-01

    Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

  20. Limited overshooting of NH{sub 4}{sup +} ions in ammonium perchlorate; Ograniczene przeskoki jonow NH{sub 4}{sup +} w nadchloranie amonowym

    Energy Technology Data Exchange (ETDEWEB)

    Birczynski, A.; Lalowicz, Z.T. [Inst. of Nuclear Physics, Cracow (Poland); Ingman, L.P.; Punkkinen, M.; Ylinen, E.E. [Wihuri Physical Lab., Turku Univ., Turku (Finland)

    1995-12-31

    The interpretation of NMR spectra for polycrystalline sample of ammonium perchlorate in helium temperature assumes the tunneling of NH{sub 4}{sup +}. Such interpretation does not agree with experimental data. The hypothesis of additional motion (fast rotation around one of C3 axis) has been checked and discussed on the base of NMR spectra of NH{sub 4}ClO{sub 4} monocrystal for the temperature range 2.1-25 K. 9 refs, 1 fig.

  1. Treatment for GaSb surfaces using a sulphur blended (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Murape, D.M., E-mail: Davison.Murape@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Eassa, N.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa)

    2012-07-01

    A sulphur based chemical, [(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na{sub 2}S{center_dot}9H{sub 2}O and (NH{sub 4}){sub 2}S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) than with (NH{sub 4}){sub 2}S or Na{sub 2}S{center_dot}9H{sub 2}O, as evidenced by the ratio of the O{sub 506eV} to Sb{sub 457eV} AES peaks. XPS results reveal that Sb{sub 2}S{sub 3}/Sb{sub 2}S{sub 5} 'replaces' Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5}, suggesting that sulphur atoms substitute oxygen atoms in Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5} to form Sb-S. It seems sulphurization only partially removes Ga{sub 2}O{sub 3}. Treatment with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

  2. Microstructural degradation of bearing steels

    OpenAIRE

    Solano Alvarez, Wilberth

    2015-01-01

    The aim of the work presented in this thesis is to clarify one of the most fundamental aspects of fatigue damage in bearings steels through critical experiments, in particular whether damage in the form of cracks precedes hard “white-etching matter" formation, which is carbon supersaturated nanoscaled ferrite. Heat treatments have been designed to create four different crack types and distributions: scarce martensite plate cracks, fine grain boundary cracks, abundant martensite plate cracks, ...

  3. Pemaknaan Pembaca terhadap Kisah-kisah Rumah Tangga Bertema Perselingkuhan dalam Rubrik Oh Mama, Oh Papa di Majalah Kartini

    OpenAIRE

    Sari, Ayu Permata; Santosa, Hedi Pudjo; Rahardjo, Turnomo

    2013-01-01

    Pemaknaan Pembaca Terhadap Kisah-kisah Rumah TanggaBertema Perselingkuhan dalam Rubrik Oh Mama, Oh Papa diMajalah KartiniSkripsiDisusun untuk memenuhi persyaratan menyelesaikanPendidikan Strata 1Jurusan Ilmu Komunikasi Fakultas Ilmu Sosial dan Imu PolitikUniversitas DiponegoroPenyusun :Ayu Permata SariD2C009109JURUSAN ILMU KOMUNIKASIFAKULTAS ILMU SOSIAL DAN ILMU POLITIKUNIVERSITAS DIPONEGOROSEMARANG2013Nama : Ayu Permata SariNIM : D2C009109Judul : Pemaknaan Pembaca Terhadap Kisah-kisah Rumah ...

  4. Observations of OH and HO2 radicals over West Africa

    Directory of Open Access Journals (Sweden)

    D. E. Heard

    2010-09-01

    Full Text Available The hydroxyl radical (OH plays a key role in the oxidation of trace gases in the troposphere. However, observations of OH and the closely related hydroperoxy radical (HO2 have been sparse, especially in the tropics. Based on a low-pressure laser-induced fluorescence technique (FAGE – Fluorescence Assay by Gas Expansion, an instrument has been developed to measure OH and HO2 aboard the Facility for Airborne Atmospheric Measurement (FAAM BAe-146 research aircraft. During the African Monsoon Multidisciplinary Analyses (AMMA campaign, observations of OH and HO2 (HOx were made in the boundary layer and free troposphere over West Africa on 13 flights during July and August 2006. Mixing ratios of both OH and HO2 were found to be highly variable, but followed a diurnal cycle: OH varied from 1.3 pptv to below the instrumental limit of detection, with a median mixing ratio of 0.17 pptv. HO2 varied from 42.7 pptv to below the limit of detection, with a median mixing ratio of 8.0 pptv. A median HO2/OH ratio of 95 was observed. Daytime OH observations were compared with the primary production rate of OH from ozone photolysis in the presence of water vapour. Daytime HO2 observations were generally reproduced by a simple steady-state HOx calculation, where HOx was assumed to be formed from the primary production of OH and lost through HO2 self-reaction. Deviations between the observations and this simple model were found to be grouped into a number of specific cases: (a within cloud, (b in the presence of high levels of isoprene in the boundary layer and (c within a biomass burning plume. HO2 was sampled in and around cloud, with significant short-lived reductions of HO2 observed. Up to 9 pptv of HO2 was observed at night, with HO2 above 6 pptv observed at altitudes above 6 km. In the forested boundary layer, HO2 was underestimated by a steady state calculation at altitudes below 500 m but overestimated between 500 m and 2 km. In a biomass burning plume

  5. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  6. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

  7. Intercomparison of OH and OH reactivity measurements in a high isoprene and low NO environment during the Southern Oxidant and Aerosol Study (SOAS)

    Science.gov (United States)

    Sanchez, Dianne; Jeong, Daun; Seco, Roger; Wrangham, Ian; Park, Jeong-Hoo; Brune, William H.; Koss, Abigail; Gilman, Jessica; de Gouw, Joost; Misztal, Pawel; Goldstein, Allen; Baumann, Karsten; Wennberg, Paul O.; Keutsch, Frank N.; Guenther, Alex; Kim, Saewung

    2018-02-01

    We intercompare OH and OH reactivity datasets from two different techniques, chemical ionization mass spectrometry (CIMS) and laser-induced fluorescence (LIF) in a high isoprene and low NO environment in a southeastern US forest during the Southern Oxidant and Aerosol Study (SOAS). An LIF instrument measured OH and OH reactivity at the top of a tower, a CIMS instrument measured OH at the top of the tower, and a CIMS based comparative reactivity method (CRM-CIMS) instrument deployed at the base of the tower measured OH reactivity. Averaged diel variations of OH and OH reactivity from these datasets agree within analytical uncertainty and correlations of LIF versus CIMS for OH and OH reactivity have slopes of 0.65 and 0.97, respectively. However, there are systematic differences between the measurement datasets. The CRM-CIMS measurements of OH reactivity were ∼16% lower than those by the LIF technique in the late afternoon. We speculate that it is caused by losses in the sampling line down to the CRM-CIMS instrument. On the other hand, we could not come up with a reasonable explanation for the difference in the LIF and CIMS OH datasets for early morning and late afternoon when OH is below 1 × 106 molecules cm-3. Nonetheless, results of this intercomparison exercise strengthen previous publications from the field site on OH concentrations and atmospheric reactivity.

  8. Bearing/Bypass Material-Testing System

    Science.gov (United States)

    Crews, John H., Jr.

    1988-01-01

    System developed to test specimens in compression as well as tension while maintaining constant bearing/bypass ration. Test specimen with centrally located hole is clamped between two bearing-guide plates using one bolt. Bearing-guide plates then secured to two bearing-load cells. Test specimen independently loaded at both ends, using two separate control systems identified as applied and bypass. If two end loads unequal, difference between them reacted as bolt-bearing load on specimen. Throughout test, two control systems synchronized by common input signal (increasing voltage). As result, loads remain proportional as they increase.

  9. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  10. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

  11. A motor with superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

    1993-01-01

    Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

  12. Heuristic explanation of journal bearing instability

    Science.gov (United States)

    Crandall, S. H.

    1982-01-01

    A fluid-filled journal bearing is viewed as a powerful pump circulating fluid around the annular space between the journal and the bearing. A small whirling motion of the journal generates a wave of thickness variation progressing around the channel. The hypothesis that the fluid flow drives the whirl whenever the mean of the pumped fluid velocity is greater than the peripheral speed of the thickness variation wave is discussed and compared with other simple explanations of journal bearing instability. It is shown that for non-cavitation long bearings the hypothesis predicts instability onset correctly for unloaded bearings but gradually overpredicts the onset speed as the load is increased.

  13. A reliability approach to machine tool bearings

    International Nuclear Information System (INIS)

    Jia Yazhou; Shen Guixiang; Jia Zhixin

    1995-01-01

    Based on the machine tool working characteristics, a method to determine the bearing dynamic load rating with a specified reliability is presented. Unlike the conventional methods for machine tool bearing design which are almost empirical, the proposed method is based on the bearing fatigue reliability. Also, unlike the common design methods of other industrial bearings which cannot consider the machine tool peculiarity, the obtained method is based on power and torque characteristics of machine tools. Designing the machine tool bearings by use of the method can obtain the expected reliability

  14. Ball Bearing Analysis with the ORBIS Tool

    Science.gov (United States)

    Halpin, Jacob D.

    2016-01-01

    Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

  15. Optimization, biological evaluation and microPET imaging of copper-64-labeled bombesin agonists, [64Cu-NO2A-(X)-BBN(7-14)NH2], in a prostate tumor xenografted mouse model

    International Nuclear Information System (INIS)

    Lane, Stephanie R.; Nanda, Prasanta; Rold, Tammy L.; Sieckman, Gary L.; Figueroa, Said D.; Hoffman, Timothy J.; Jurisson, Silvia S.; Smith, Charles J.

    2010-01-01

    Gastrin-releasing peptide receptors (GRPr) are a member of the bombesin (BBN) receptor family. GRPr are expressed in high numbers on specific human cancers, including human prostate cancer. Therefore, copper-64 ( 64 Cu) radiolabeled BBN(7-14)NH 2 conjugates could have potential for diagnosis of human prostate cancer via positron-emission tomography (PET). The aim of this study was to produce [ 64 Cu-NO2A-(X)-BBN(7-14)NH 2 ] conjugates for prostate cancer imaging, where X=pharmacokinetic modifier (beta-alanine, 5-aminovaleric acid, 6-aminohexanoic acid, 8-aminooctanoic acid, 9-aminonanoic acid or para-aminobenzoic acid) and NO2A=1,4,7-triazacyclononane-1,4-diacetic acid [a derivative of NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid)]. Methods: [(X)-BBN(7-14)NH 2 ] Conjugates were synthesized by solid-phase peptide synthesis (SPPS), after which NOTA was added via manual conjugation. The new peptide conjugates were radiolabeled with 64 Cu radionuclide. The receptor-binding affinity was determined in human prostate PC-3 cells, and tumor-targeting efficacy was determined in PC-3 tumor-bearing severely combined immunodeficient (SCID) mice. Whole-body maximum intensity microPET/CT images of PC-3 tumor-bearing SCID mice were obtained 18 h postinjection (pi). Results: Competitive binding assays in PC-3 cells indicated high receptor-binding affinity for the [NO2A-(X)-BBN(7-14)NH 2 ] and [ nat Cu-NO2A-(X)-BBN(7-14)NH 2 ] conjugates. In vivo biodistribution studies of the [ 64 Cu-NO2A-(X)-BBN(7-14)NH 2 ] conjugates at 1, 4 and 24 h pi showed very high uptake of the tracer in GRPr-positive tissue with little accumulation and retention in nontarget tissues. High-quality, high-contrast microPET images were obtained, with xenografted tumors being clearly visible at 18 h pi. Conclusions: NO2A chelator sufficiently stabilizes copper(II) radiometal under in vivo conditions, producing conjugates with very high uptake and retention in targeted GRPr. Preclinical evaluation of these

  16. Lions and tigers and bears, oh my! Three barriers to progress in computer-aided molecular design

    Science.gov (United States)

    Clark, Robert D.; Waldman, Marvin

    2012-01-01

    The computational chemistry and cheminformatics community faces many challenges to advancing the state of the art. We discuss three of those challenges here: accurately estimating the contribution of entropy to ligand binding; reliably estimating the uncertainties in model predictions for new molecules; and being able to effectively curate the ever-expanding literature and commercial databases needed to build new models.

  17. Estabilidade da sílica biogênica extraída de capim Jaraguá (Hyparrhenia rufa em solução de NaOH Stability of biogenic silica extract of Jaraguá grass (Hyparrhenia rufa in NaOH solution

    Directory of Open Access Journals (Sweden)

    Liovando M. Costa

    2010-01-01

    Full Text Available Biogenic silica is used to describe compounds of hydrated silica (SiO2.nH2O, with specific shapes and sizes, deposited in plants. The chemical composition of biogenic silica and its stability in Jaraguá grass was studied in increasing concentration of NaOH. The analytical results demonstrated high concentration of Si, Al, Fe, Mg, P and low of Cu, Cd and Zn in the phytoliths composition. The silica bodies stability in NaOH solution with increasing concentration was different among the shapes and sizes. Silicified stomata and silicified plant tissues were dissolved along with the dumbbells because they are the less stable forms of biogenic silica.

  18. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    OpenAIRE

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and...

  19. Coupled Dynamics of a Rotor-Journal Bearing System Equipped with Thrust Bearings

    OpenAIRE

    Yu Lie; R.B. Bhat

    1995-01-01

    The rotordynamic coefficients of fixed-pad thrust bearing are introduced and calculated by using the out-domain method, and a general analysis method is developed to investigate the coupled dynamics of a rotor equipped with journal and thrust bearings simultaneously. Considerations include the effects of static tilt parameters of the rotor on rotordynamic coefficients of thrust bearing and the action of thrust bearing on system dynamics. It is shown that thrust bearing changes the load distri...

  20. SURVEY OBSERVATIONS OF A POSSIBLE GLYCINE PRECURSOR, METHANIMINE (CH{sub 2}NH)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Taiki; Ohishi, Masatoshi; Hirota, Tomoya; Saito, Masao [Department of Astronomy, the Graduate University for Advanced Studies (SOKENDAI), Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Majumdar, Liton; Wakelam, Valentine, E-mail: taiki.suzuki@nao.ac.jp [Univ. Bordeaux, LAB, UMR 5804, F-33270, Floirac (France)

    2016-07-01

    We conducted survey observations of a glycine precursor, methanimine, or methylenimine (CH{sub 2}NH), with the Nobeyama Radio Observatory 45 m telescope and the Sub-Millimeter Radio telescope toward 12 high-mass and two low-mass star-forming regions in order to increase the number of known CH{sub 2}NH sources and to better understand the characteristics of CH{sub 2}NH sources. As a result of our survey, CH{sub 2}NH was detected in eight sources, including four new sources. The estimated fractional abundances were ∼10{sup −8} in Orion KL and G10.47+0.03, while they were ∼10{sup −9} toward the other sources. Our hydrogen recombination line and past studies suggest that CH{sub 2}NH-rich sources have less (this mean not so evolved) evolved H ii regions. The lower destruction rates from UV flux from the central star would contribute to the high CH{sub 2}NH abundances toward CH{sub 2}NH-rich sources. Our gas-grain chemical simulations suggest that CH{sub 2}NH is mostly formed in the gas phase by neutral–neutral reactions, rather than being the product of thermal evaporation from dust surfaces.

  1. Theoretical study on the mechanism of CH3NH2 and O3 ...

    Indian Academy of Sciences (India)

    file, PEP, for the mechanism of CH3NH2+ O3 reaction to find a way to eliminate methylamine from the ... 03 program.16 Geometrical parameters of the reactants, products, intermediates (denoted as INs) .... intermediates and transition states in the CH3NH2+O3 reaction on the singlet PEP. Species. RB3LYP. ZPE. CCSD(T).

  2. Atmospheric NH3 as plant nutrient: A case study with Brassica oleracea

    International Nuclear Information System (INIS)

    Castro, Ana; Stulen, Ineke; De Kok, Luit J.

    2008-01-01

    Nutrient-sufficient and nitrate- or sulfate-deprived plants of Brassica oleracea L. were exposed to 4 μl l -1 NH 3 (2.8 mg m -3 ), and effects on biomass production and allocation, N-compounds and root morphology investigated. Nitrate-deprived plants were able to transfer to atmospheric NH 3 as nitrogen source, but biomass allocation in favor of the root was not changed by exposure to NH 3 . NH 3 reduced the difference in total root length between nitrate-sufficient and nitrate-deprived plants, and increased the specific root length in the latter. The internal N status, therefore, might be involved in controlling root length in B. oleracea. Root surface area, volume and diameter were unaffected by both nitrate deprivation and NH 3 exposure. In sulfate-deprived plants an inhibitory effect of NH 3 on root morphological parameters was observed. These plants, therefore, might be more susceptible to atmospheric NH 3 than nitrate-deprived plants. The relevance of the present data under field conditions is discussed. - Atmospheric NH 3 can serve as sole N source for Brassica oleracea, but does not change root biomass allocation in nitrate-deprived plants

  3. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib

    2012-01-01

    temperatures and a low NH3-to-H2 ratio, the catalytic activity of the best Ni-Fe/Al2O3 catalyst was found to be comparable or even better to that of a more expensive Ru-based catalyst. Small Ni-Fe nanoparticle sizes are crucial for an optimal overall NH3 conversion because of a structural effect favoring...

  4. First principles study of NH3 molecular adsorption on LiH (100) surfaces

    International Nuclear Information System (INIS)

    Lu Xiaoxia; Chen Yuhong; Dong Xiao

    2012-01-01

    The adsorption of NH 3 on LiH (100) crystal surfaces was studied by first principles method. The preferred adsorption sites, adsorption energy, dissociation energy and electronic structure of the LiH (100)/NH 3 systems were calculated separately. It is found that chemical adsorption happened mainly when NH 3 molecules are on the LiH (100) crystal surfaces. When NH 3 is adsorbed on the Li top site, NH 2 is formed on the LiH (100) crystal surfaces after loss of H atom, the calculated adsorption energy, 0.511 eV, belongs to strong chemical adsorption, then the interaction is strongest. The interaction between NH 2 and the neighboring Li, H are ionic. The covalent bonds are formed between N and H atoms in NH 2 . One H 2 molecule is formed by another H atom in NH 3 and H atom from LiH (100) crystal sur- faces. The covalent bonds are formed between H and H atoms in H 2 . (authors)

  5. Study on Control of NH4 +-N in Surface Water by Photocatalytic

    Science.gov (United States)

    Zuo, Xiaoran; He, Honghua; Yang, Yue; Yan, Chao; Zhou, Ying

    2018-01-01

    NH4 +-N has become the main pollution factor affecting the surface water quality in China. Based on the theory of photolysis, the feasibility of photolysis removing NH4 +-N in surface water is studied. The effects of pH, CaO2 content and photolysis time on removal rate of NH4 +-N are studied. The actual study is based on Laboratory studies results. Experimental results show: When the pH8, the photolysis can greatly reduce the NH4 +-N content in water. CaO2 can greatly remove NH4 +-N. The removal rate of NH4 +-N increased with the increase of photocatalytic time. When irradiated with UV light for 108 hours or the sun is irradiated for about 40 days, NH4 +-N content can be reduced from 4mg/L to 0.5mg/L under the optimum experimental conditions. Adjusting the pH of surface water is the most important condition for controlling NH4 +-N content.

  6. Chromatographic (TLC) differentiation of grizzly bear and black bear scats

    Science.gov (United States)

    Picton, Harold D.; Kendall, Katherine C.

    1994-01-01

    While past work concluded that thin-layer chromatography (TLC) was inadequate for the separation of grizzly (Ursus arctos horribilis) and black bear (U. americanus) scats, our study found differences adequate for species separation. A key was constructed using 19 of 40 data points recorded on each(N)=356 profiles of 178) know-species scat. Accuracy was best for late summer scats (94%). Methods for specimen preparation, analysis, and reading the TLC profiles are discussed. Factors involved in scat variation were tested.

  7. Proton location in (CH3)3N-H+-(CH3OH)n: A theoretical and infrared spectroscopic study

    International Nuclear Information System (INIS)

    Bing, Dan; Hamashima, Toru; Tsai, Chen-Wei; Fujii, Asuka; Kuo, Jer-Lai

    2013-01-01

    Highlights: • Preferential location of the excess proton in the trimethylamine-methanol clusters. • Collaboration between DFT calculations and IR spectroscopy. • The excess proton prefers the protonation to the trimethylamine moiety. - Abstract: The dependence of the preferential protonated site in (CH 3 ) 3 N-H + -(CH 3 OH) n on the cluster size was investigated using theoretical calculations and infrared spectroscopy measurements. While simple estimation from the magnitude of proton affinity suggested that the excess proton prefers the methanol site in n ⩾ 4, density functional theory calculations of the stabilization energy indicated the clear preference as protonation of the trimethylamine site, even for n = 9. Infrared spectra of the clusters were observed for n = 3–7. Spectral simulations were also performed using the quantum harmonic superposition approximation. The observed (CH 3 ) 3 N-H + -(CH 3 OH) n spectra were well interpreted by simulations of the isomers with the protonated trimethylamine ion core. It was shown that both the proton affinity and the mutual solvation energy govern the preferential location of the excess proton in binary component clusters

  8. A prototype construction of bearing heater system

    International Nuclear Information System (INIS)

    Firman Silitonga

    2007-01-01

    A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

  9. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  10. Gas-phase reactions of [VO2(OH)2]- and [V2O5(OH)]- with methanol: experiment and theory.

    Science.gov (United States)

    Harris, Benjamin L; Waters, Tom; Khairallah, George N; O'Hair, Richard A J

    2013-02-14

    The gas-phase reactivity of the vanadium hydroxides [VO(2)(OH)(2)](-) and [V(2)O(5)(OH)](-) toward methanol was examined using a combination of ion-molecule reactions (IMRs) and collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer. Isotope-labeling experiments with CD(3)OH, (13)CH(3)OH, and CH(3)(18)OH were used to confirm the stoichiometry of ions and the observed sequence of reactions. The experimental data were interpreted with the aid of density functional theory calculations, carried out at the B3LYP/SDD6-311++G** level of theory. While [VO(2)(OH)(2)](-) is unreactive, [V(2)O(5)(OH)](-) undergoes a metathesis reaction to yield [V(2)O(5)(OCH(3))](-). The DFT calculations reveal that the metathesis reaction of methanol with [VO(2)(OH)(2)](-) suffers from a barrier of +0.52 eV (relative to separated reactants) but that the reaction of [V(2)O(5)(OH)](-) with methanol readily proceeds via addition/elimination reactions with both transition states being below the energy of the separated reactants. CID of [V(2)O(5)(OCH(3))](-) (m/z 213) yields three ions arising from activation of the methoxo ligand: [V(2), O(6), C, H](-) (m/z 211); [V(2), O(5), H](-) (m/z 183); and [V(2), O(4), H](-) (m/z 167). Additional experiments and DFT calculations suggest that these ions arise from losses of H(2), formaldehyde and the sequential losses of H(2) and CO(2), respectively. The use of an (18)O-labeled methoxo ligand in [V(2)O(5)((18)OCH(3))](-) (m/z 215) showed the competing losses of H(2)C(16)O and H(2)C(18)O and [H(2) and C(16)O(18)O] and [H(2) and C(16)O(2)], highlighting that (16)O/(18)O exchange between the methoxo ligand and the vanadium oxide occurs prior to the subsequent fragmentation of the ligand. DFT calculations reveal that a key step involves hydrogen atom transfer from the methoxo ligand to the oxo ligand of the same vanadium center, producing the intermediate [V(2)O(4)(OH)(OCH(2))](-) containing a ketyl radical ligand and a hydroxo ligand

  11. Evaluation of rotating, incompressibly lubricated, pressurized thrust bearings

    Science.gov (United States)

    Fleming, D. P.

    1971-01-01

    Program evaluates a series hybrid, fluid film ball bearing consisting of an orifice compensated pressurized thrust bearing in conjunction with a self-acting journal bearing. Oil viscosities corresponding to experimentally measured ball bearing outer-race temperatures were used.

  12. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

    Science.gov (United States)

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-03-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  13. The structure and the analytical potential energy function of NH2 (X2B1)

    International Nuclear Information System (INIS)

    Liu Yufang; Jiang Lijuan; Ma Heng; Sun Jinfeng

    2008-01-01

    This paper reports that the equilibrium structure of NH 2 has been optimized at the QCISD/6-311++G (3df, 3pd) level. The ground-state NH 2 has a bent (C 2v , X 2 B 1 ) structure with an angle of 103.0582°. The geometrical structure is in good agreement with the other calculational and experimental results. The harmonic frequencies and the force constants have also been calculated. Based on the group theory and the principle of microscopic reversibility, the dissociation limits of NH 2 (C 2v , X 2 B 1 ) have been derived. The potential energy surface of NH 2 (X 2 B 1 ) is reasonable. The contour lines are constructed, the structure and energy of NH 2 reappear on the potential energy surface

  14. NH125 kills methicillin-resistant Staphylococcus aureus persisters by lipid bilayer disruption.

    Science.gov (United States)

    Kim, Wooseong; Fricke, Nico; Conery, Annie L; Fuchs, Beth Burgwyn; Rajamuthiah, Rajmohan; Jayamani, Elamparithi; Vlahovska, Petia M; Ausubel, Frederick M; Mylonakis, Eleftherios

    2016-01-01

    NH125, a known WalK inhibitor kills MRSA persisters. However, its precise mode of action is still unknown. The mode of action of NH125 was investigated by comparing its spectrum of antimicrobial activity and its effects on membrane permeability and giant unilamellar vesicles (GUVs) with walrycin B, a WalR inhibitor and benzyldimethylhexadecylammonium chloride (16-BAC), a cationic surfactant. NH125 killed persister cells of a variety of Staphylococcus aureus strains. Similar to 16-BAC, NH125 killed MRSA persisters by inducing rapid membrane permeabilization and caused the rupture of GUVs, whereas walrycin B did not kill MRSA persisters or induce membrane permeabilization and did not affect GUVs. NH125 kills MRSA persisters by interacting with and disrupting membranes in a detergent-like manner.

  15. Rotational spectrum of the NH3–He van der Waals complex

    Directory of Open Access Journals (Sweden)

    Surin L.

    2017-01-01

    Full Text Available The interaction between ammonia and helium has attracted considerable interest over many years, partly because of the observation of interstellar ammonia. The rate coefficients of NH3–He scattering are an important ingredient for numerical modeling of astrochemical environments. Another, though quite different application in which the NH3–He interaction can play an important role is the doping of helium clusters with NH3 molecules to perform high-resolution spectroscopy. Such experiments are directed on the detection of non-classical response of molecular rotation in helium clusters addressing fundamental questions related to the microscopic nature of superfluidity. High-resolution spectroscopy on the NH3–He complex is an important tool for increasing our understanding of intermolecular forces between NH3 and He.

  16. Hydroxyl radicals (. OH) and the toxicity of oral iron

    Energy Technology Data Exchange (ETDEWEB)

    Kang, J.O.; Slivka, A.; Cohen, G.

    1986-05-01

    Oral iron salts are widely prescribed for a variety of medical uses. Accidental overdoses has caused serious pathological consequences, especially in young children. Because iron is absorbed most efficiently when it is in the ferrous form, most oral preparations consist of a ferrous salt. Many preparations additionally contain ascorbic acid in order to maintain the iron in the reduced state. Ferrous ions in solution are readily oxidized by molecular oxygen, and can generate reactive products, including .OH. In this study, the authors demonstrate that intragastric instillation of a ferrous salt and ascorbic acid in rats produces .OH. .OH was detected by its reaction with intragastric 2-keto-4-methylthiobutyric acid to yield ethylene gas. Animals were placed into sealed rebreathing chambers and chamber ethylene was measured by gas chromatography. The authors studied a dose range of 10-100 mg ferrous sulfate (7H20) per 250 g rat. In experiments conducted in vitro, ascorbate had a biphasic action, increasing the yield of ethylene at low concentrations, but suppressing the yield at higher concentrations. Almost complete inhibition of product formation by catalase in vitro shows the involvement of hydrogen peroxide as an intermediate. The authors suggest that .OH a formed in vivo via a Fenton reaction between ferrous ions and generated hydrogen peroxide, and that .OH may be responsible, in part, for damage to the GI tract by the oral iron.

  17. An -OH group functionalized MOF for ratiometric Fe3+ sensing

    Science.gov (United States)

    Xu, Hui; Dong, Yingying; Wu, Yuhang; Ren, Wenjing; Zhao, Tao; Wang, Shunli; Gao, Junkuo

    2018-02-01

    Iron is one of the most important elements in the biochemical processes in all living system, both deficiency or excess of iron will lead to metabolism disorder diseases. However, Fe3+ is one of the most efficient fluorescence quenchers among the transition-metal ions because of its paramagnetic nature. The realization of Fe3+ ratiometric and self-calibrated fluorescent sensor is highly-challenging. We synthesized a novel luminescent -OH functionalized EuOHBDC (Eu2(OH-BDC)3, OH-BDC=2-hydroxyterephthalic acid) by hydrothermal reaction and in situ ligand synthesis, and used it as a rare ratiomatric luminescent sensor for Fe3+ ions. The -OH functional group facilitates both electron transfer and binding interaction between EuOHBDC and Fe3+, which lead to luminescent quenching of ligand-based emission while enhancement of a new peak emission, and thus enables ratiometric detection of Fe3+. The relative fluorescent intensity ratio (I375/I427) increased linearly with increasing Fe3+ concentration in the 10-50 μM range with 1.17 μM (65 ppb) detection limit. The EuOHBDC also shows excellent selectivity towards different metal ions, particularly can discriminate Fe3+ and Fe2+ through different luminescent responses. This result clearly demonstrates the superiority of -OH functionalized MOF for Fe3+ detection, which can contribute to develop high performance luminescent probe for detection of metal ions in environmental and biomedical applications.

  18. Photofragment imaging study of the CH2CCH2OH radical intermediate of the OH+allene reaction

    International Nuclear Information System (INIS)

    Raman, Arjun S.; Justine Bell, M.; Lau, K.-C.; Butler, Laurie J.

    2007-01-01

    These velocity map imaging experiments characterize the photolytic generation of one of the two radical intermediates formed when OH reacts via an addition mechanism with allene. The CH 2 CCH 2 OH radical intermediate is generated photolytically from the photodissociation of 2-chloro-2-propen-1-ol at 193 nm. Detecting the Cl atoms using [2+1] resonance-enhanced multiphoton ionization evidences an isotropic angular distribution for the Cl+CH 2 CCH 2 OH photofragments, a spin-orbit branching ratio for Cl( 2 P 1/2 ):Cl( 2 P 3/2 ) of 0.28, and a bimodal recoil kinetic energy distribution. Conservation of momentum and energy allows us to determine from this data the internal energy distribution of the nascent CH 2 CCH 2 OH radical cofragment. To assess the possible subsequent decomposition pathways of this highly vibrationally excited radical intermediate, we include electronic structure calculations at the G3//B3LYP level of theory. They predict the isomerization and dissociation transition states en route from the initial CH 2 CCH 2 OH radical intermediate to the three most important product channels for the OH+allene reaction expected from this radical intermediate: formaldehyde+C 2 H 3 , H+acrolein, and ethene+CHO. We also calculate the intermediates and transition states en route from the other radical adduct, formed by addition of the OH to the center carbon of allene, to the ketene+CH 3 product channel. We compare our results to a previous theoretical study of the O+allyl reaction conducted at the CBS-QB3 level of theory, as the two reactions include several common intermediates

  19. Photofragment imaging study of the CH2CCH2OH radical intermediate of the OH +allene reaction

    Science.gov (United States)

    Raman, Arjun S.; Justine Bell, M.; Lau, Kai-Chung; Butler, Laurie J.

    2007-10-01

    These velocity map imaging experiments characterize the photolytic generation of one of the two radical intermediates formed when OH reacts via an addition mechanism with allene. The CH2CCH2OH radical intermediate is generated photolytically from the photodissociation of 2-chloro-2-propen-1-ol at 193nm. Detecting the Cl atoms using [2+1] resonance-enhanced multiphoton ionization evidences an isotropic angular distribution for the Cl +CH2CCH2OH photofragments, a spin-orbit branching ratio for Cl(P1/22):Cl(P3/22) of 0.28, and a bimodal recoil kinetic energy distribution. Conservation of momentum and energy allows us to determine from this data the internal energy distribution of the nascent CH2CCH2OH radical cofragment. To assess the possible subsequent decomposition pathways of this highly vibrationally excited radical intermediate, we include electronic structure calculations at the G3//B3LYP level of theory. They predict the isomerization and dissociation transition states en route from the initial CH2CCH2OH radical intermediate to the three most important product channels for the OH +allene reaction expected from this radical intermediate: formaldehyde+C2H3, H +acrolein, and ethene+CHO. We also calculate the intermediates and transition states en route from the other radical adduct, formed by addition of the OH to the center carbon of allene, to the ketene+CH3 product channel. We compare our results to a previous theoretical study of the O +allyl reaction conducted at the CBS-QB3 level of theory, as the two reactions include several common intermediates.

  20. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  1. A thermodynamic model for the solubility of NpO2(am) in the aqueous K+-HCO3--CO32--OH--H2O system

    International Nuclear Information System (INIS)

    Rai, D.; Hess, N.J.; Felmy, A.R.; Moore, D.A.; Yui, M.

    1999-01-01

    Solubility of NpO 2 (am) was determined in the aqueous K + -HCO 3 - -CO 3 2- -OH - -H 2 O system extending to high concentrations of carbonate, bicarbonate, and mixed carbonate-hydroxide. Several reducing agents (Fe powder, Na 2 S 2 O 4 , NH 2 . NH 2 , and NH 2 OH . HCl) were tested for their effectiveness to maintain neptunium in the tetravalent state. Of these reducing agents, Na 2 S 2 O 4 was found to be the most effective. Even in the presence of Na 2 S 2 O 4 , significant oxidation of Np(IV) to Np(V) occurred in samples containing relatively low concentrations of carbonate/bicarbonate, relatively high concentrations of hydroxide, and samples equilibrated for relatively long periods. X-ray absorption spectroscopy (XAS) and solvent extraction were used to identify aqueous species and oxidation states and to help select appropriate data sets for thermodynamic interpretations. The dominant aqueous species in CO 3 2- and relatively concentrated HCO 3 - solutions was found by XAS to be Np(CO 3 ) 5 6- . Solubility of NpO 2 (am) in carbonate and bicarbonate solutions increased dramatically with increasing molal concentrations (carbonate >0.1 moles per kg H 2 O (m) and bicarbonate >0.01 m), indicating that carbonate makes strong complexes with Np(IV). The dominant Np(IV)-carbonate species that reasonably described all of the experimental data were Np(CO 3 ) 5 6- in low to high concentrations of carbonate and hydroxide and in high concentrations of bicarbonate, and Np(OH) 2 (CO 3 ) 2 2- in low concentrations of bicarbonate. The logarithm of the thermodynamic equilibrium constants for the NpO 2 (am) dissolution reactions involving these species [(NpO 2 (am) + 5 CO 3 2- + 4 H + Np(CO 3 ) 3 6- + 2 H 2 O) and (NpO 2 (am) + 2 HCO 3 - Np(OH) 2 (CO 3 ) 2 2- )] were found to be 34.85 and -4.44, respectively. These values, when combined with the solubility product of NpO 2 (am) [log K Sp = -54.9 [1, and recent unpublished data from Rai et al.

  2. Removing Gaseous NH3 Using Biochar as an Adsorbent

    Directory of Open Access Journals (Sweden)

    Kyoung S. Ro

    2015-09-01

    Full Text Available Ammonia is a major fugitive gas emitted from livestock operations and fertilization production. This study tested the potential of various biochars in removing gaseous ammonia via adsorption processes. Gaseous ammonia adsorption capacities of various biochars made from wood shaving and chicken litter with different thermal conditions and activation techniques were determined using laboratory adsorption column tests. Ammonia adsorption capacities of non-activated biochars ranged from 0.15 to 5.09 mg·N/g, which were comparable to that of other commercial activated carbon and natural zeolite. There were no significant differences in ammonia adsorption capacities of steam activated and non-activated biochars even if the surface areas of the steam activated biochars were about two orders of magnitude greater than that of non-activated biochars. In contrast, phosphoric acid activation greatly increased the biochar ammonia adsorption capacity. This suggests that the surface area of biochar did not readily control gaseous NH3 adsorption. Ammonia adsorption capacities were more or less linearly increased with acidic oxygen surface groups of non-activated and steam-activated biochars. Phosphoric acid bound to the acid activated biochars is suspected to contribute to the exceptionally high ammonia adsorption capacity. The sorption capacities of virgin and water-washed biochar samples were not different, suggesting the potential to regenerate spent biochar simply with water instead of energy- and capital-intensive steam. The results of this study suggest that non-activated biochars can successfully replace commercial activated carbon in removing gaseous ammonia and the removal efficiency will greatly increase if the biochars are activated with phosphoric acid.

  3. 24,25(OH)2D3 enhances the calcemic effect of 1,25(OH)2D3 in PTX rats.

    Science.gov (United States)

    Wald, H; Traves, J; Popovtzer, M M

    1987-01-01

    The effect of 24,25(OH)2D3 on 1,25(OH)2D3-induced hypercalcemia was studied in parathyroidectomized (PTX) rats for 10 days. Serum (S) and urinary Ca excretion (UCaV) were measured in (a) control rats, (b) rats receiving a daily sc injection of 54 ng 1,25(OH)2D3, (c) rats receiving 24,25(OH)2D3 in the same dose and same manner, and (d) rats receiving 1,25(OH)2D3 + 24,25(OH)2D3. Our results show that (i) 24,25(OH)2D3 alone does not increase SCa2+ in PTX rats, (ii) combined administration of 1,25(OH)2D3 + 24,25(OH)2D3 enhances the hypercalcemic response to 1,25(OH)2D3 without a parallel increase in UCaV, (iii) combined administration of 1,25(OH)2D3 + 24,25(OH)2D3 reduces the rise in urinary excretion of Ca2+ compared with that of rats receiving 1,25(OH)2D3 alone for 10 days, and (iv) these alterations are independent of parathyroid hormone.

  4. Precision magnetic suspension linear bearing

    Science.gov (United States)

    Trumper, David L.; Queen, Michael A.

    1992-01-01

    We have shown the design and analyzed the electromechanics of a linear motor suitable for independently controlling two suspension degrees of freedom. This motor, at least on paper, meets the requirements for driving an X-Y stage of 10 Kg mass with about 4 m/sq sec acceleration, with travel of several hundred millimeters in X and Y, and with reasonable power dissipation. A conceptual design for such a stage is presented. The theoretical feasibility of linear and planar bearings using single or multiple magnetic suspension linear motors is demonstrated.

  5. SiO 2 nanospheres with tailorable interiors by directly controlling Zn 2+ and NH 3·H 2O species in an emulsion process

    Science.gov (United States)

    Liao, Yuchao; Wu, Xiaofeng; Wang, Zhen; Chen, Yun-Fa

    2011-07-01

    SiO 2 nanospheres with tailorable interiors were synthesized by a facile one-spot microemulsion process using TEOS as silica source, wherein cyclohexane including triton X-100 and n-octanol as oil phase and Zn 2+ or NH 3·H 2O aqueous solution as dispersive phase, respectively. The products were characterized by Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray Powder Diffraction. It was suggested that the as-synthesized silica nanospheres possessed grape-stone-like porous or single hollow interior, and also found that the ammonia dosage and aging time played key roles in controlling the size and structure of silica nanospheres. Furthermore, the comparative results confirmed that in-situ zinc species [ZnO/Zn(OH) 2] acted as the temporary templates to construct grape-stone-like interior, and a simultaneously competing etching process occurred owing to the soluble Zn(NH 3) 42+ complex formation while the additional excessive ammonia was introduced. With the aging time being extended, the in-situ nanocrystals tended to grow into bigger ones by Ostwald Ripening, producing single hollow interior.

  6. Comparative fate of organohalogen contaminants in two top carnivores in Greenland: captive sledge dogs and wild polar bears.

    Science.gov (United States)

    Verreault, Jonathan; Dietz, Rune; Sonne, Christian; Gebbink, Wouter A; Shahmiri, Soheila; Letcher, Robert J

    2008-04-01

    The limited knowledge and/or the inability to control physiological condition parameters that influence the fate of organohalogen contaminants (OHCs) has been the foremost confounding aspect in monitoring programs and health risk assessments of wild top predators in the Arctic such as the polar bear (Ursus maritimus). In the present comparative study, we used a potential surrogate Canoidea species for the East Greenland polar bear, the captive sledge dog (Canis familiaris), to investigate some factors that may influence the bioaccumulation and biotransformation of major chlorinated and brominated OHCs in adipose tissue and blood (plasma) of control (fed commercial pork fat) and exposed (fed West Greenland minke whale (Balaenoptera acutorostrata) blubber) adult female sledge dogs. Furthermore, we compared the patterns and concentrations of OHCs and their known or suggested hydroxylated (OH) metabolites (e.g., OH-PCBs) in sledge dogs with those in adipose tissue and blood (plasma) of East Greenland adult female polar bears, and blubber of their main prey species, the ringed seal (Pusa hispida). The two-year feeding regime conducted with sledge dogs led to marked differences in overall adipose tissue (and plasma) OHC residue accumulation between the control and exposed groups. Characteristic prey-to-predator OHC bioaccumulation dynamics for major PCB and PBDE congeners (patterns and concentrations) and biotransformation capacity with respect to PCB metabolite formation and OH-PCB retention distinguished, to some extent, captive sledge dogs and wild polar bears. Based on the present findings, we conclude that the use of surrogate species in toxicological investigations for species in the Canoidea family should be done with great caution, although they remain essential in the context of contaminants research with sensitive arctic top carnivore species such as the polar bear.

  7. Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

    Science.gov (United States)

    Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

    2016-01-01

    Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  9. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  10. Saturation kinetics in phenolic O-H bond oxidation by a mononuclear Mn(III)-OH complex derived from dioxygen.

    Science.gov (United States)

    Wijeratne, Gayan B; Corzine, Briana; Day, Victor W; Jackson, Timothy A

    2014-07-21

    The mononuclear hydroxomanganese(III) complex, [Mn(III)(OH)(dpaq)](+), which is supported by the amide-containing N5 ligand dpaq (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate) was generated by treatment of the manganese(II) species, [Mn(II)(dpaq)](OTf), with dioxygen in acetonitrile solution at 25 °C. This oxygenation reaction proceeds with essentially quantitative yield (greater than 98% isolated yield) and represents a rare example of an O2-mediated oxidation of a manganese(II) complex to generate a single product. The X-ray diffraction structure of [Mn(III)(OH)(dpaq)](+) reveals a short Mn-OH distance of 1.806(13) Å, with the hydroxo moiety trans to the amide function of the dpaq ligand. No shielding of the hydroxo group is observed in the solid-state structure. Nonetheless, [Mn(III)(OH)(dpaq)](+) is remarkably stable, decreasing in concentration by only 10% when stored in MeCN at 25 °C for 1 week. The [Mn(III)(OH)(dpaq)](+) complex participates in proton-coupled electron transfer reactions with substrates with relatively weak O-H and C-H bonds. For example, [Mn(III)(OH)(dpaq)](+) oxidizes TEMPOH (TEMPOH = 2,2'-6,6'-tetramethylpiperidine-1-ol), which has a bond dissociation free energy (BDFE) of 66.5 kcal/mol, in MeCN at 25 °C. The hydrogen/deuterium kinetic isotope effect of 1.8 observed for this reaction implies a concerted proton-electron transfer pathway. The [Mn(III)(OH)(dpaq)](+) complex also oxidizes xanthene (C-H BDFE of 73.3 kcal/mol in dimethylsulfoxide) and phenols, such as 2,4,6-tri-t-butylphenol, with BDFEs of less than 79 kcal/mol. Saturation kinetics were observed for phenol oxidation, implying an initial equilibrium prior to the rate-determining step. On the basis of a collective body of evidence, the equilibrium step is attributed to the formation of a hydrogen-bonding complex between [Mn(III)(OH)(dpaq)](+) and the phenol substrates.

  11. Morphological and taxonomic affinities of the Olduvai ulna (OH 36).

    Science.gov (United States)

    Aiello, L C; Wood, B; Key, C; Lewis, M

    1999-05-01

    The OH 36 ulna derives from Upper Bed II in the Olduvai Gorge, and is dated to circa 1.1-1.2 Myr. Multivariate analyses incorporating data from samples of modern humans, common and pygmy chimpanzees, gorillas, orangutans, and two other early hominin ulnae, Omo L40-19 and KNM-BK 66, suggest that OH 36 belonged to an individual with powerful forearms consistent with a locomotor repertoire that included arboreal locomotion. However, there is no compelling evidence that it made regular use of its forelimbs as supports when travelling on the ground. When compared with levels of intra- and intertaxon size and shape variation in the comparative sample (humans, chimpanzees, gorillas), the differences between OH 36, KNM-BK 66, and Omo L40-19 are compatible with OH 36 differing from the other two fossil hominin ulnae to the extent that modern humans differ from modern great apes. KNM-BK 66 and Omo L40-19 differ from each other in overall size and shape only to the degree that would be expected within any of the individual modern comparative samples. Based on these analyses, there is no evidence to support the hypothesis that OH 36 and Omo L40-19 belong to the same species of fossil hominin, or to two species that shared a similar forelimb locomotor repertoire. We suggest that OH 36 has the greater claim to be assigned to Paranthropus boisei, and we recommend that for the time being the latter be referred to the tribe Hominini gen. et sp. indet. The surprising result of these analyses is the overall size and shape similarity between Omo L40-19 and KNM-BK 66, two fossils that are separated in time by more than 1.5 million years, and which have traditionally been assumed to represent hominin species with quite different locomotor patterns.

  12. The Far Infrared Lines of OH as Molecular Cloud Diagnostics

    Science.gov (United States)

    Smith, Howard A.

    2004-01-01

    Future IR missions should give some priority to high resolution spectroscopic observations of the set of far-IR transitions of OH. There are 15 far-IR lines arising between the lowest eight rotational levels of OH, and ISO detected nine of them. Furthermore, ISO found the OH lines, sometimes in emission and sometimes in absorption, in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds to active galactic nuclei and ultra-luminous IR galaxies. The ISO/LWS Fabry-Perot resolved the 119 m doublet line in a few of the strong sources. This set of OH lines provides a uniquely important diagnostic for many reasons: the lines span a wide wavelength range (28.9 m to 163.2 m); the transitions have fast radiative rates; the abundance of the species is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and, not least, the powerful centimeter-wave radiation from OH allows comparison with radio and VLBI datasets. The problem is that the large number of sensitive free parameters, and the large optical depths of the strongest lines, make modeling the full set a difficult job. The SWAS montecarlo radiative transfer code has been used to analyze the ISO/LWS spectra of a number of objects with good success, including in both the lines and the FIR continuum; the DUSTY radiative transfer code was used to insure a self-consistent continuum. Other far IR lines including those from H2O, CO, and [OI] are also in the code. The OH lines all show features which future FIR spectrometers should be able to resolve, and which will enable further refinements in the details of each cloud's structure. Some examples are given, including the case of S140, for which independent SWAS data found evidence for bulk flows.

  13. Why Does Alkylation of the N-H Functionality within M/NH Bifunctional Noyori-Type Catalysts Lead to Turnover?

    Science.gov (United States)

    Dub, Pavel A; Scott, Brian L; Gordon, John C

    2017-01-25

    Molecular metal/NH bifunctional Noyori-type catalysts are remarkable in that they are among the most efficient artificial catalysts developed to date for the hydrogenation of carbonyl functionalities (loadings up to ∼10 -5 mol %). In addition, these catalysts typically exhibit high C═O/C═C chemo- and enantioselectivities. This unique set of properties is traditionally associated with the operation of an unconventional mechanism for homogeneous catalysts in which the chelating ligand plays a key role in facilitating the catalytic reaction and enabling the aforementioned selectivities by delivering/accepting a proton (H + ) via its N-H bond cleavage/formation. A recently revised mechanism of the Noyori hydrogenation reaction (Dub, P. A. et al. J. Am. Chem. Soc. 2014, 136, 3505) suggests that the N-H bond is not cleaved but serves to stabilize the turnover-determining transition states (TDTSs) via strong N-H···O hydrogen-bonding interactions (HBIs). The present paper shows that this is consistent with the largely ignored experimental fact that alkylation of the N-H functionality within M/NH bifunctional Noyori-type catalysts leads to detrimental catalytic activity. The purpose of this work is to demonstrate that decreasing the strength of this HBI, ultimately to the limit of its complete absence, are conditions under which the same alkylation may lead to beneficial catalytic activity.

  14. Improved GaSb surfaces using a (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}S0{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Murape, D.M., E-mail: Davison.Murape@live.nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Eassa, N.; Nyamhere, C.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2012-05-15

    Bulk (1 0 0) n-GaSb surfaces have been treated with a sulphur based solution ((NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}) to which sulphur has been added, not previously reported for the passivation of GaSb surfaces. Au/n-GaSb Schottky barrier diodes (SBDs) fabricated on the treated material show significant improvement compared to that of the similar SBDs on the as-received material as evidenced by the lower ideality factor (n), higher barrier height ({phi}{sub b}) and lower contact resistance obtained. Additionally, the reverse leakage current, although not saturating, has been reduced by almost an order of magnitude at -0.2 V. The sample surfaces were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The native oxide, Sb-O, present on the as-received material is effectively removed on treating with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}]+S) and (NH{sub 4}){sub 2}S. Analysis of the as-received surface by XPS, prior to and after argon sputtering, suggests that the native oxide layer is {<=}8.5 nm.

  15. Synchrotron FTIR imaging of OH in quartz mylonites

    Directory of Open Access Journals (Sweden)

    A. K. Kronenberg

    2017-10-01

    Full Text Available Previous measurements of water in deformed quartzites using conventional Fourier transform infrared spectroscopy (FTIR instruments have shown that water contents of larger grains vary from one grain to another. However, the non-equilibrium variations in water content between neighboring grains and within quartz grains cannot be interrogated further without greater measurement resolution, nor can water contents be measured in finely recrystallized grains without including absorption bands due to fluid inclusions, films, and secondary minerals at grain boundaries.Synchrotron infrared (IR radiation coupled to a FTIR spectrometer has allowed us to distinguish and measure OH bands due to fluid inclusions, hydrogen point defects, and secondary hydrous mineral inclusions through an aperture of 10 µm for specimens > 40 µm thick. Doubly polished infrared (IR plates can be prepared with thicknesses down to 4–8 µm, but measurement of small OH bands is currently limited by strong interference fringes for samples < 25 µm thick, precluding measurements of water within individual, finely recrystallized grains. By translating specimens under the 10 µm IR beam by steps of 10 to 50 µm, using a software-controlled x − y stage, spectra have been collected over specimen areas of nearly 4.5 mm2. This technique allowed us to separate and quantify broad OH bands due to fluid inclusions in quartz and OH bands due to micas and map their distributions in quartzites from the Moine Thrust (Scotland and Main Central Thrust (Himalayas.Mylonitic quartzites deformed under greenschist facies conditions in the footwall to the Moine Thrust (MT exhibit a large and variable 3400 cm−1 OH absorption band due to molecular water, and maps of water content corresponding to fluid inclusions show that inclusion densities correlate with deformation and recrystallization microstructures. Quartz grains of mylonitic orthogneisses and paragneisses deformed

  16. Synchrotron FTIR imaging of OH in quartz mylonites

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Andreas K.; Hasnan, Hasnor F. B.; Holyoke III, Caleb W.; Law, Richard D.; Liu, Zhenxian; Thomas, Jay B.

    2017-01-01

    Previous measurements of water in deformed quartzites using conventional Fourier transform infrared spectroscopy (FTIR) instruments have shown that water contents of larger grains vary from one grain to another. However, the non-equilibrium variations in water content between neighboring grains and within quartz grains cannot be interrogated further without greater measurement resolution, nor can water contents be measured in finely recrystallized grains without including absorption bands due to fluid inclusions, films, and secondary minerals at grain boundaries.

    Synchrotron infrared (IR) radiation coupled to a FTIR spectrometer has allowed us to distinguish and measure OH bands due to fluid inclusions, hydrogen point defects, and secondary hydrous mineral inclusions through an aperture of 10 µm for specimens > 40 µm thick. Doubly polished infrared (IR) plates can be prepared with thicknesses down to 4–8 µm, but measurement of small OH bands is currently limited by strong interference fringes for samples < 25 µm thick, precluding measurements of water within individual, finely recrystallized grains. By translating specimens under the 10 µm IR beam by steps of 10 to 50 µm, using a software-controlled x-y stage, spectra have been collected over specimen areas of nearly 4.5 mm2. This technique allowed us to separate and quantify broad OH bands due to fluid inclusions in quartz and OH bands due to micas and map their distributions in quartzites from the Moine Thrust (Scotland) and Main Central Thrust (Himalayas).

    Mylonitic quartzites deformed under greenschist facies conditions in the footwall to the Moine Thrust (MT) exhibit a large and variable 3400 cm-1 OH absorption band due to molecular water, and maps of water content corresponding to fluid inclusions show that inclusion densities correlate with deformation and recrystallization microstructures. Quartz grains of mylonitic orthogneisses and

  17. Serum 25(OH)D and incident type 2 diabetes

    DEFF Research Database (Denmark)

    Husemoen, L L N; Skaaby, T; Thuesen, B H

    2012-01-01

    Mild to moderate vitamin D insufficiency has been proposed as a risk factor for several common chronic diseases including type 2 diabetes. This study aimed to examine the association between serum 25-hydroxy vitamin D (25(OH)D) and incident diabetes.......Mild to moderate vitamin D insufficiency has been proposed as a risk factor for several common chronic diseases including type 2 diabetes. This study aimed to examine the association between serum 25-hydroxy vitamin D (25(OH)D) and incident diabetes....

  18. Coupled Dynamics of a Rotor-Journal Bearing System Equipped with Thrust Bearings

    Directory of Open Access Journals (Sweden)

    Yu Lie

    1995-01-01

    Full Text Available The rotordynamic coefficients of fixed-pad thrust bearing are introduced and calculated by using the out-domain method, and a general analysis method is developed to investigate the coupled dynamics of a rotor equipped with journal and thrust bearings simultaneously. Considerations include the effects of static tilt parameters of the rotor on rotordynamic coefficients of thrust bearing and the action of thrust bearing on system dynamics. It is shown that thrust bearing changes the load distribution of journal bearings and the static deflection of the rotor and delays the instability of the system considerably in lateral shaft vibration.

  19. The dual action gas thrust bearing - A new high load bearing concept

    Science.gov (United States)

    Etsion, I.

    1976-01-01

    The principle of utilizing hydrodynamic effects in diverging films for improving load capacity in gas thrust bearings is discussed. A new concept of dual action bearing based on that principle is described and analyzed. The potential of the new bearing is demonstrated both analytically for an infinitely long slider and by numerical solution for a flat sector shaped thrust bearing. It is shown that the dual action bearing can extend substantially the range of load carrying capacity in gas lubricated thrust bearings and improve their efficiency.

  20. Construction of gas suspended bearings (radial and axial gas ball bearings)

    International Nuclear Information System (INIS)

    Kaspar, G.

    1974-10-01

    This report contains practical and theoretical results that were obtained at IPP in the section of gas suspended bearings. The two air-cushioned, air-driven revolving mirrors and an air-cushioned, air measuring coil drive were built. The latter has a double radial bearing and a single axial bearing. The axial bearing is shaped in such a way that, with slight throttling of the air feed, i.e. at low air intake pressure, a relatively high bearing load can be imposed and the bearing remains at the same time free of the so-called air hammer effect. (orig.) [de

  1. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH3

    International Nuclear Information System (INIS)

    Gwo, Dz-Hung; California Univ., Berkeley, CA

    1989-11-01

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH 3 and (NH 3 ) 2 , generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH 3 , and the other six belong to (NH 3 ) 2 . To facilitate the intermolecular vibrational assignment for Ar--NH 3 , a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH 3 centered at 26.470633(17) cm -1 can correlate only to either the fundamental dimeric stretching band for the A 2 states with the NH 3 inversional quantum number v i = 1, or the K a = 0 left-arrow 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface

  2. Penggunaan zeolit alam untuk mengurangi kandungan krom dan nh4+ dalam air limbah penyamakan kulit

    Directory of Open Access Journals (Sweden)

    Supraptiningsih Supraptiningsih

    2006-07-01

    Full Text Available Leather tanning waste water contains chemical compounds, such as chromium and NH4+ in high concentration, so if they are thrown away without treatment they will make some problems. The aims of this research is to adsorb the cations in leather tanning waste water i.e chromium and NH4+ used natural zeolite as an adsorbent. Research was done by comparing amount of chromium and NH4+ in effluent waste water treatment unit with amount of chromium and NH4+ after being adsorbed by zeolite in a batch system. The result of this research showed that efficiency difference between using zeolite and waste water treatment unit was significant. The optimal condition to reduce chromium and NH4+ was by using 300 grams per liter waste, zeolite particle size was 50-60 mesh, contact time was 24 hours and pH 8±0,1. In this condition, zeolites could reduce chromium from 3728,56mg/l to 365,39 mg/l or 90,20%, and NH4+ from 3040,02 mg/l menjadi 209,76 mg/l or 93,10%. Waste water treatment unit could reduce chromium 63,55% and NH4+ 56,75%.

  3. Towards validation of ammonia (NH3) measurements from the IASI satellite

    Science.gov (United States)

    Van Damme, M.; Clarisse, L.; Dammers, E.; Liu, X.; Nowak, J. B.; Clerbaux, C.; Flechard, C. R.; Galy-Lacaux, C.; Xu, W.; Neuman, J. A.; Tang, Y. S.; Sutton, M. A.; Erisman, J. W.; Coheur, P. F.

    2015-03-01

    Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI) satellite has been observing NH3 from space at a high spatio-temporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement, but they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows investigations of the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented.

  4. PRAXIS: low thermal emission high efficiency OH suppressed fibre spectrograph

    Science.gov (United States)

    Content, Robert; Bland-Hawthorn, Joss; Ellis, Simon; Gers, Luke; Haynes, Roger; Horton, Anthony; Lawrence, Jon; Leon-Saval, Sergio; Lindley, Emma; Min, Seong-Sik; Shortridge, Keith; Staszak, Nick; Trinh, Christopher; Xavier, Pascal; Zhelem, Ross

    2014-07-01

    PRAXIS is a second generation instrument that follows on from GNOSIS, which was the first instrument using fibre Bragg gratings for OH suppression to be deployed on a telescope. The Bragg gratings reflect the NIR OH lines while being transparent to the light between the lines. This gives in principle a much higher signal-noise ratio at low resolution spectroscopy but also at higher resolutions by removing the scattered wings of the OH lines. The specifications call for high throughput and very low thermal and detector noise so that PRAXIS will remain sky noise limited even with the low sky background levels remaining after OH suppression. The optical and mechanical designs are presented. The optical train starts with fore-optics that image the telescope focal plane on an IFU which has 19 hexagonal microlenses each feeding a multi-mode fibre. Seven of these fibres are attached to a fibre Bragg grating OH suppression system while the others are reference/acquisition fibres. The light from each of the seven OH suppression fibres is then split by a photonic lantern into many single mode fibres where the Bragg gratings are imprinted. Another lantern recombines the light from the single mode fibres into a multi-mode fibre. A trade-off was made in the design of the IFU between field of view and transmission to maximize the signal-noise ratio for observations of faint, compact objects under typical seeing. GNOSIS used the pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph specifically designed for the fibre Bragg grating OH suppression and optimised for 1.47 μm to 1.7 μm (it can also be used in the 1.09 μm to 1.26 μm band by changing the grating and refocussing). This results in a significantly higher transmission due to high efficiency coatings, a VPH grating at low incident angle and optimized for our small bandwidth, and low absorption glasses. The detector noise will also be lower thanks to the use of a current generation HAWAII-2RG detector

  5. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  6. Bearing Health Assessment Based on Chaotic Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Lu

    2013-01-01

    Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

  7. Empirical and mechanistic evaluation of NH4(+) release kinetic in calcareous soils.

    Science.gov (United States)

    Ranjbar, F; Jalali, M

    2014-05-01

    Release, fixation, and distribution of ammonium (NH4(+)) as a source of nitrogen can play an important role in soil fertility and plant nutrition. In this study, ten surface soils, after addition of 1,000 mg NH4(+) kg(-1,) were incubated for 1 week at the field capacity moisture and 25 ± 2 °C temperature, and then NH4(+) release kinetic was investigated by sequential extractions with 10 mM CaCl2. Furthermore, NH4(+) distribution among three fractions, including water-soluble, exchangeable, and non-exchangeable, was determined in all soil samples. NH4(+) release was initially rapid followed by a slower reaction, and this was described well with the Elovich equation as an empirical model. The cumulative NH4(+) concentration released in spiked soil samples had a positive significant correlation with sand content and negative ones with pH, exchangeable Ca(2+)m and K(+), cation exchange capacity (CEC), equivalent calcium carbonate (ECC), and clay content. The cation exchange model in the PHREEQC program was successful in mechanistic simulation of the release trend of native and added NH4(+) in all control and spiked soil samples. The results of fractionation experiments showed that the non-exchangeable fraction in control and spiked soil samples was greater than that in water-soluble and exchangeable fractions. Soil properties, such as pH, exchangeable Ca(2+) and K(+), CEC, ECC, and contents of sand and clay, had significant influences on the distribution of NH4(+) among three measured fractions. This study indicated that both native and recently fixed NH4(+), added to soil through the application of fertilizers, were readily available for plant roots during 1 week after exposure.

  8. An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements

    Directory of Open Access Journals (Sweden)

    E. Dammers

    2016-08-01

    Full Text Available Global distributions of atmospheric ammonia (NH3 measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs = 547 give a mean relative difference of −32.4 ± (56.3 %, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (−50 to +100 %.

  9. Are organohalogen contaminants a bears (Ursus maritimus)?

    DEFF Research Database (Denmark)

    Sonne, Christian; Dietz, Rune; Leifsson, PS

    2006-01-01

    Tissues of polar bears (Ursus maritimus) from East Greenland contain the highest concentrations of organohalogen contaminants (OHCs) among subpopulations of any mammalian species in the Arctic. Negative associations also have been found between OHC concentrations and bone mineral density and liver...... histology parameters for this subpopulation of polar bears. The present study examined the OHC concentrations and adverse effects on renal tissue for 75 polar bears collected during 1999 to 2002. Specific lesions were diffuse glomerular capillary wall thickening, mesangial glomerular deposits, tubular...

  10. Deterioration Assessment of Bridge Rubber Bearings

    OpenAIRE

    Gu, Haosheng; 伊藤, 義人; Itoh, Yoshito

    2005-01-01

    Natural rubber (NR) with lead plugs and high damping rubber (HDR) are often used for base-isolated rubber bearings. However, it is usually known that ageing causes rubber performance to drop. This research is to study the deterioration characteristics of these two kinds of bridge rubber bearings through accelerated thermal oxidation tests. The property variations inside the aged rubber blocks are investigated. For natural rubber bearing, the mechanical properties on the surface change the mos...

  11. BEARING TESTS FOR THE SPUR TURBOGENERATOR.

    Science.gov (United States)

    The results of the liquid-potassium journalbearing test program for the SPUR turbogenerator are presented. The activities described include the design, assembly and checkout of the bearing test rig, and the results of a successfully completed 250-h endurance test on a hydrodynamic journal bearing using 600 F liquid potassium as the lubricant. Unidirectional loads from 6 to 25 lbs were applied to the bearing operating at a speed of 24,000 rpm. (Author)

  12. The international research progress of Ammonia(NH3) emissions and emissions reduction technology in farmland ecosystem

    Science.gov (United States)

    Yang, W. Z.; Jiao, Y.

    2017-03-01

    NH3 is the important factor leading to the grey haze, and one of the main causes of environmental problems of serious ecological imbalance, such as acid rain and air quality deterioration. The fertilizer excessive application of the current farmland results NH3 emissions intensity greatly. In order to clear the farmland NH3 emissions research status and achievements, the literature of farmland NH3 emission related were retrievaled by the SCI journals and Chinese science citation database. Some factors of NH3 emission were analyzed such as soil factors, climate factors and farmland management measures. The research progress was inductived on farmland NH3 emission reduction technology. The results will help to clarify farmland NH3 emissions research progress. The theoretical guidance was provided on the future of farmland NH3 emissions research.

  13. Plasma chemistry in an atmospheric pressure Ar/NH3 dielectric barrier discharge

    DEFF Research Database (Denmark)

    Fateev, A.; Leipold, F.; Kusano, Y.

    2005-01-01

    An atmospheric pressure dielectric barrier discharge (DBD) in Ar/NH3 (0.1 - 10%) mixtures with a parallel plate electrode geometry was studied. The plasma was investigated by emission and absorption spectroscopy in the UV spectral range. Discharge current and voltage were measured as well. UV...... of an atmospheric pressure Ar/NH3 DBD are H-2, N-2 and N2H4. The hydrazine (N2H4) concentration in the plasma and in the exhaust gases at various ammonia concentrations and different discharge powers was measured. Thermal N2H4 decomposition into NH2 radicals may be used for NOx reduction processes....

  14. The Spectrum of Jupiter's Great Red Spot: The Case for Ammonium Hydrosulfide (NH4SH)

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.

    2016-01-01

    Here we present new ultraviolet-visible spectra of irradiated ammonium hydrosul?de (NH4SH), a reported Jovian atmospheric cloud component, for a range of temperatures and radiation doses and make assignments to the spectral features. We show that the combination of radiolysis and thermal annealing of NH4SH causes the originally featureless ultraviolet-visible re?ectance spectrum to evolve into one that absorbs in the ultraviolet-visible region. Furthermore, we ?nd that our laboratory spectra resemble HST (Hubble Space Telescope) spectra below 500 nanometers, suggesting that the more stable reaction products of NH4SH radiolysis are likely an important component of the Great Red Spot.

  15. The Spectrum of Jupiters Great Red Spot: the Case for Ammonium Hydrosulfide (NH4SH)

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.

    2016-01-01

    Here we present new ultraviolet-visible spectra of irradiated ammonium hydrosul?de (NH4SH), a reported Jovian atmospheric cloud component, for a range of temperatures and radiation doses and make assignments to the spectral features. We show that the combination of radiolysis and thermal annealing of NH4SH causes the originally featureless ultraviolet-visible re?ectance spectrum to evolve into one that absorbs in the ultraviolet-visible region. Furthermore, we ?nd that our laboratory spectra resemble HST (Hubble Space Telescope) spectra below 500 nanometers, suggesting that the more stable reaction products of NH4SH radiolysis are likely an important component of the Great Red Spot.

  16. Technical Development Path for Gas Foil Bearings

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  17. Hydrogen abstraction from CH3NH2, (CH3)2 NH, and (CH3)3 N by HO˙2 radicals: A theoretical study

    Science.gov (United States)

    Shi, J. C.; Shang, Y. L.; Du, S. Y.; Luo, S. N.

    2018-01-01

    Hydrogen abstraction from CH3NH2, (CH3)2 NH, and (CH3)3 N by HO˙2 radicals, is investigated via quantum chemistry calculations.The B3LYP/6-31G(2df, p) method is employed in geometry optimizations, frequencies, and intrinsic reaction coordinate calculations. The G4 method is applied in energy and thermodynamical property calculations. Rate constants are obtained from variation transition state theory and conventional transition state theory calculations with one-dimensional hindered rotor treatment and Eckart tunneling correction. A branching ratio analysis for each reaction system is further performed.

  18. EFFECTS OF NaOH MODIFICATION ON THE MECHANICAL ...

    African Journals Online (AJOL)

    In order to improve properties of natural fibers as reinforcement, different treatment methods have being adopted by researchers. However, the use of sodium hydroxide (NaOH) for the treatment of baobab pod fiber as reinforcement in low density polyethylene is sparsely reported. Therefore, this study, investigated the effect ...

  19. Aesthetic Relationships and Ethics in "The Oh Fuck Moment"

    Science.gov (United States)

    Breel, Astrid

    2015-01-01

    This article explores the aesthetics and ethics of participatory performance through "The Oh Fuck Moment" by Hannah Jane Walker and Chris Thorpe, a performance that aesthetically explores ethically troubling material and manipulation. Ethical criticism of participatory art in recent years has focused on the way the audience member is…

  20. Hydrothermal synthesis of porous Co (OH) 2 nanoflake array film ...

    Indian Academy of Sciences (India)

    ... -Co(OH)2 nanoflake array film exhibits high capacitances of 1017 F g-1 at 2Ag-1 and 890 F g-1 at 40Ag-1 as well as rather good cycling stability for supercapacitor application. The porous architecture is responsible for the enhancement of the electrochemical properties because it provides fast ion and electron transfer, ...

  1. Transition metal chemistry of hydroxy(–OH)-rich molecules ...

    Indian Academy of Sciences (India)

    Administrator

    Transition metal chemistry of hydroxy(–OH)-rich molecules: Syntheses, crystal structures and solution reactivity studies. MISHTU DEY 1, P K SAARENKETO 2, E KOLEHMAINEN 2,. K RISSANEN 2 and CHEBROLU P RAO 1. 1Bioinorganic Laboratory, Department of Chemistry, Indian Institute of. Technology Bombay, Powai ...

  2. Mechanism of the CO2-Ca(OH)2 reaction

    International Nuclear Information System (INIS)

    Chew, V.S.; Cheh, C.H.; Glass, R.W.

    1983-01-01

    Recent studies clearly showed the importance of moisture in achieving high Ca(OH) 2 absorbent utilization for removing CO 2 from gas streams at ambient temperatures. However, the role of moisture and the mechanism of the reaction was not well understood. This paper summarizes the results of a study of the mechanism of the CO 2 -Ca(OH) 2 reaction with emphasis on the role of moisture. The reaction between Ca(OH) 2 and CO 2 in moist N 2 was found to be first order with respect to the reactants with a rate constant of about 100 min -1 . At high humidities, the rate of reaction was chemically controlled, but at low humidities, the reaction rate was limited by the diffusion through the carbonate layer formed by the reaction. Calculations showed that capillary condensation could have occurred only in about 2% of the pore volume and was unlikely to have affected the reaction rate significantly by allowing the reaction to occur in the liquid phase. It was, therefore, concluded that the main role of moisture was to improve the Ca(OH) 2 utilization by lowering the resistance to diffusion through the carbonate layer

  3. Fabrication of hierarchical β-Co(OH)2 microspheres via ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Hierarchical β-Co(OH)2 microspheres with 20–50 µm diameter assembled from nanoplate building blocks were successfully fabricated via a hydrothermal process in the presence of a cation surfactant cetyl- trimethylammonium bromide (CTAB). The products are characterized in detail by multiform techniques: X-.

  4. OHS Encourages People to Hike Despite the Heat | Poster

    Science.gov (United States)

    Even the blazing heat could not stop people from enjoying the Occupational Health Services’ (OHS) most recent Take a Hike event, which promoted healthy living. The red, white, and blue–themed, 1.3-mile walk was the fifth such event since 2014 for NCI at Frederick. People got out of their offices to exercise, show off their patriotism, and win prizes.

  5. On satellite lines anomalies in OH excited states

    International Nuclear Information System (INIS)

    Elitzur, M.

    1976-01-01

    It is argued that different pumps produce similar distributions of populations in the first two excited states of OH. The pattern observed recently in G 219.3 - 07 by Whiteoak and Gardner can be due either to radiative or collisional pump. (author)

  6. Assessment of the exchange parameters of Amberlite IR-45 (OH ...

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: Simple quantitative technique has been developed for assessing the exchange parameters of Amberlite IR. – 45 (OH) using column chromatographic techniques from the displacement of exchangeable hydroxyl ions of the resin by sulphate ions. The results obtained showed retention time of 33min, retention ...

  7. Transition metal chemistry of hydroxy(–OH)-rich molecules ...

    Indian Academy of Sciences (India)

    Administrator

    Appropriately designed hydroxy(–OH) containing Schiff's base and Mannich base molecules have been recently found to be important for development of the coordination chemistry of a number of metal ions in the biomimetic chemistry of metalloenzymes. In this context, our group has studied the coordination role of these ...

  8. Spatially extended OH+ emission from the Orion Bar and Ridge

    NARCIS (Netherlands)

    van der Tak, F. F. S.; Nagy, Z.; Ossenkopf, V.; Makai, Z.; Black, J. H.; Faure, A.; Gerin, M.; Bergin, E. A.

    2013-01-01

    Context. The reactive HnO+ ions (OH+, H2O+ and H3O+) are widespread in the interstellar medium and act as precursors to the H2O molecule. While HnO+ absorption is seen on many Galactic lines of sight, active galactic nuclei often show the lines in emission. Aims: This paper shows the first example

  9. 76 FR 66250 - Television Broadcasting Services; Cleveland, OH

    Science.gov (United States)

    2011-10-26

    ...] Television Broadcasting Services; Cleveland, OH AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: The Commission has before it a petition for rulemaking filed by Community Television of Ohio License, LLC (``Community Television''), the licensee of station WJW (TV), channel 8, Cleveland...

  10. Assessment of the exchange parameters of Amberlite IR-45 (OH ...

    African Journals Online (AJOL)

    Simple quantitative technique has been developed for assessing the exchange parameters of Amberlite IR – 45 (OH) using column chromatographic techniques from the displacement of exchangeable hydroxyl ions of the resin by sulphate ions. The results obtained showed retention time of 33min, retention volume of ...

  11. ACCURATE OH MASER POSITIONS FROM THE SPLASH PILOT REGION

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hai-Hua; Shen, Zhi-Qiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai, 200030 (China); Walsh, Andrew J.; Jordan, Christopher H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth WA 6845 (Australia); Green, James A. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, Epping, NSW 2121 (Australia); Breen, Shari L. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Dawson, J. R. [Department of Physics and Astronomy and MQ Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109 (Australia); Ellingsen, Simon P. [School of Physical Sciences, Private Bag 37,University of Tasmania, Hobart 7001, TAS (Australia); Gómez, José F. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Lowe, Vicki; Jones, Paul A., E-mail: qiaohh@shao.ac.cn [Department of Astrophysics and Optic, School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

    2016-12-01

    We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centers previously identified in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) pilot region, between Galactic longitudes of 334° and 344° and Galactic latitudes of −2° and +2°. Supplementing our data with data from the MAGMO (Mapping the Galactic Magnetic field through OH masers) survey, we find maser emission toward 175 of the 196 target fields. We conclude that about half of the 21 nondetections were due to intrinsic variability. Due to the superior sensitivity of the followup ATCA observations, and the ability to resolve nearby sources into separate sites, we have identified 215 OH maser sites toward the 175 fields with detections. Among these 215 OH maser sites, 111 are new detections. After comparing the positions of these 215 maser sites to the literature, we identify 122 (57%) sites associated with evolved stars (one of which is a planetary nebula), 64 (30%) with star formation, two sites with supernova remnants, and 27 (13%) of unknown origin. The infrared colors of evolved star sites with symmetric maser profiles tend to be redder than those of evolved star sites with asymmetric maser profiles, which may indicate that symmetric sources are generally at an earlier evolutionary stage.

  12. Supramolecular network formed through OH $\\cdots $ O and - ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 4. Supramolecular network formed through O-H ⋯ O and - stacking interactions: Hydrothermal syntheses and crystal structures of M(H2O)6](optp)2 (M = Mg, Ni, Zn, and optp = 1-oxopyridinium-2-thiopropionate). Murugan Indrani Ramasamy ...

  13. CTEPP-OH DATA CHILD DAY CARE CENTER WEEKLY MENUS

    Science.gov (United States)

    This data set contains information on the weekly day care menus for CTEPP-OH. The day care centers provided menus up to three months prior to field sampling. The Children’s Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study was one of the larg...

  14. The middle infrared properties of OH megamaser host galaxies

    Science.gov (United States)

    Zhang, J. S.; Wang, J. Z.; Di, G. X.; Zhu, Q. F.; Guo, Q.; Wang, J.

    2014-10-01

    We compiled all 119 OH maser galaxies (110 out of them are megamasers, i.e., LOH> 10 L⊙) published so far and cross-identified these OH masers with the Wide-Field Infrared Survey Explorer (WISE) catalog, to investigate the middle infrared (MIR) properties of OH maser galaxies. The WISE magnitude data at the 3.4, 4.6, 12 and 22 μm (W1 to W4) are collected for the OH maser sample and one control sample, which are non-detection sources. The color-color diagrams show that both OH megamaser (OHM) and non-OHM (ultra)luminous infrared galaxies ((U)LIRGs) are far away from the single blackbody model line and many of them can follow the path described by the power-law model. The active galaxy nuclei (AGN) fraction is about ~40% for both OHM and non-OHM (U)LIRGs, according to the AGN criteria W1 - W2 ≥ 0.8. Among the Arecibo survey sample, OHM sources tend to have a lower luminosity at short MIR wavelengths (e.g., 3.4 μm and 4.6 μm) than that of non-OHM sources, which should come from the low OHM fraction among the survey sample with large 3.4 μm and 4.6 μm luminosity. The OHM fraction tends to increase with cooler MIR colors (larger F22 μm/F3.4 μm). These may be good for sample selection when searching OH megamasers, such as excluding extreme luminous sources at short MIR wavelengths, choosing sources with cooler MIR colors. In the case of the power-law model, we derived the spectral indices for our samples. For the Arecibo survey sample, OHM (U)LIRGs tend to have larger spectral index α22-12 than non-OHM sources, which agrees with previous results. One significant correlation exists between the WISE infrared luminosity at 22μm and the color [W1]-[W4] for the Arecibo OHM hosts. These clues should provide suitable constraints on the sample selection for OH megamaser surveys by future advanced telescopes (e.g., FAST). In addition, the correlation of maser luminosity and the MIR luminosity of maser hosts tends to be non-significant, which may indirectly support

  15. Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.

    Science.gov (United States)

    Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

    2012-04-20

    Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

  16. Experimental Evaluation of Journal Bearing Stability and New Gas Bearing Material

    Science.gov (United States)

    Keith, Theo G., Jr.; Dimofte, Florin

    2001-01-01

    It has been estimated that the noise levels in aircraft engine transmissions can be reduced by as much as 10 dB through the use of journal bearings. The potential benefits of lower noise levels include reduced wear, longer gear life and enhanced comfort for passengers and crew. Based on this concept the journal-thrust wave bearing was analyzed and its performance was evaluated. Numerical codes, developed over the past 30 years by Dr. Dimofte, were used to predict the performance of the bearing. The wave bearing is a fluid film bearing and therefore was analyzed using the Reynolds pressure equation. The formulation includes turbulent flow concepts and possesses a viscosity-temperature correction. The centrifugal growth of the bearing diameter and the deformation of the bearing under gear loads were also incorporated into the code. An experimental rig was developed to test the journal-thrust wave bearing.

  17. Gearbox Reliability Collaborative Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.

    2011-10-01

    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  18. Aluminum (III) and gallium (III) complexes with methyliminodiacetic acid: Crystal structures of Cat[M(Mida)2] (Cat+=Na, K, NH4; M3+=Al, Ga) and Me4N[Ga(Mida)2]·H2O

    International Nuclear Information System (INIS)

    Ilyukhin, A.B.; Petrosyants, S.P.; Milovanov, S.V.; Malyarik, M.A.

    1997-01-01

    The bis chelate complexes Cat[M(Mida) 2 ] and Me 4 N[Ga(Mida) 2 ]·H 2 O are synthesized from aqueous solutions M(NO 3 ) 3 -2H 2 Mida-CatOH (M 3+ =Al, Ga; Cat + =Na, K, NH 4 ) and Ga(OH) 3 -2H 2 Mida-Me 4 NOH. The crystal structures of the isostructural compounds Cat[M(Mida) 2 ] (Cat=Na, M=Al; Cat=K, M=Al; Cat=Na, M=Ga) and Me 4 N[Ga(Mida) 2 ]·H 2 O are determined by X-ray structure analysis. According to the X-ray powder diffraction analysis, all the six compounds Cat[M(Mida) 2 ] (Cat=Na, K, NH 4 ; M=Al, Ga) are isostructural. The octahedral anion in Cat[M(Mida) 2 ] and Me 4 N[Ga(Mida) 2 ]·H 2 O exhibits a trans(N)- fac configuration

  19. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  20. Evaluating 4 years of atmospheric ammonia (NH3) over Europe using IASI satellite observations and LOTOS-EUROS model results

    NARCIS (Netherlands)

    Damme, M. van; Wichink Kruit, R.J.; Schaap, M.; Clarisse, L.; Clerbaux, C.; Coheur, P.F.; Dammers, E.; Dolman, A.J.; Erisman, J.W.

    2014-01-01

    Monitoring ammonia (NH3) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH3 distributions generally relies on model calculations. Novel remotely sensed NH3burdens provide valuable insights to

  1. Artefactual 25-OH vitamin D concentration in multiple myeloma.

    Science.gov (United States)

    Ong, Michal Ws; Salota, Rashim; Reeman, Tracy; Lapsley, Marta; Jones, Lydia

    2017-11-01

    The most commonly used techniques to measure vitamin D are automated immunoassays which are known to be affected by interferences, especially from immunoglobulins present in the patient's serum. We present a case of a patient with myeloma in whom interference with the vitamin D assay was identified. An 83-year-old female, known to have IgG myeloma, was found to have a high concentration of 25-OH vitamin D on a routine test without any signs of vitamin D toxicity. She was not taking vitamin D supplements or any other multivitamin preparation and had minimal sun exposure. The initial and subsequent samples run by the ARCHITECT 25-OH vitamin D assay (chemiluminescent microparticle immunoassay technology, Abbott Laboratories, Abbott Park, IL) showed a high concentration of 25-OH vitamin D of 281 nmol/L and 327 nmol/L, respectively. Further fresh samples taken for 25-OH vitamin D and analysed by liquid chromatography-mass spectrometry (LC-MS/MS) and ARCHITECT analysis showed results of 49 nmol/L and 289 nmol/L, respectively. Our patient had high concentrations of circulating IgG paraproteins and had a long history of rheumatoid arthritis; paraproteins and rheumatoid factor may interfere in the assay. In conclusion, we report a case of a patient with IgG myeloma and rheumatoid arthritis with high concentrations of 25-OH vitamin D detected by the Abbott ARCHITECT, but not by a reference method (LC-MS/MS). The most likely cause of the discordant results is interference in the immunoassay by the paraprotein but interference from rheumatoid factor remains a possibility.

  2. Prospective association of 25(OH)D with metabolic syndrome.

    Science.gov (United States)

    Kayaniyil, Sheena; Harris, Stewart B; Retnakaran, Ravi; Vieth, Reinhold; Knight, Julia A; Gerstein, Hertzel C; Perkins, Bruce A; Zinman, Bernard; Hanley, Anthony J

    2014-04-01

    Vitamin D may play a role in the aetiology of the metabolic syndrome (MetS), yet the majority of previous studies have been cross-sectional, and the limited number of prospective studies has yielded inconsistent results. To examine the prospective association of vitamin D [25-hydroxyvitamin D, 25(OH)D] with MetS in a multi-ethnic cohort of adults in Ontario, Canada. Nondiabetic individuals with pre-existing MetS risk factors were recruited for participation in the PROspective Metabolism and ISlet cell Evaluation (PROMISE) cohort study, a longitudinal study of the determinants of insulin resistance and MetS. Of the 654 participants enrolled at baseline, 489 attended a 3-year follow-up visit. There were 301 participants eligible for the analysis of 25(OH)D with incident MetS (age 49·2 ± 9·3 years old, 75·4% female), after excluding 188 (38·5%) prevalent MetS cases at baseline. Longitudinal change in MetS components was assessed in the entire follow-up cohort. There were 76 (15·5%) participants who developed MetS over the 3-years of follow-up. Multivariate logistic regression analyses indicated a decreased risk of MetS at follow-up per standard deviation increase in baseline 25(OH)D after adjustment for sociodemographics, season, baseline and change in supplement use and physical activity and insulin resistance (OR = 0·63, 95% CI 0·44-0·90). Multivariate linear regression analyses revealed a significant inverse association of baseline 25(OH)D with fasting glucose at follow-up (β = -0·0005, P = 0·025). There was a significant inverse association of baseline 25(OH)D with incident MetS, which may be partly driven by its association with glucose homoeostasis. © 2013 John Wiley & Sons Ltd.

  3. Long-term bearing wear tests of conventional journal bearings and development of hydrostatic bearings for the LOFT drag-disc turbine transducer

    International Nuclear Information System (INIS)

    Fincke, J.R.

    1979-01-01

    The details of a two-year development program concerning materials for use as turbine bearings in a pressurized water reactor environment are reported. Two types of bearings have been examined, both conventional journal bearings and hydrostatic bearings. The results of long-term bearing wear tests conducted at 590 K and 15.1 MPa in water are presented. The feasibility of using hydrostatic bearings for the same transducer is demonstrated

  4. G331.512–0.103: An Interstellar Laboratory for Molecular Synthesis. I. The Ortho-to-para Ratios for CH3OH and CH3CN

    Science.gov (United States)

    Mendoza, Edgar; Bronfman, Leonardo; Duronea, Nicolas U.; Lépine, Jacques R. D.; Finger, Ricardo; Merello, Manuel; Hervías-Caimapo, Carlos; Gama, Diana R. G.; Reyes, Nicolas; Åke-Nyman, Lars

    2018-02-01

    Spectral line surveys reveal rich molecular reservoirs in G331.512–0.103, a compact radio source in the center of an energetic molecular outflow. In this first work, we analyze the physical conditions of the source by means of CH3OH and CH3CN. The observations were performed with the APEX Telescope. Six different system configurations were defined to cover most of the band within (292–356) GHz as a consequence, we detected a forest of lines toward the central core. A total of 70 lines of A/E–CH3OH and A/E–CH3CN were analyzed, including torsionally excited transitions of CH3OH ({ν }t=1). In a search for all the isotopologues, we identified transitions of 13CH3OH. The physical conditions were derived considering collisional and radiative processes. We found common temperatures for each A and E symmetry of CH3OH and CH3CN; the derived column densities indicate an A/E equilibrated ratio for both tracers. The results reveal that CH3CN and CH3OH trace a hot and cold component with {T}k∼ 141 K and {T}k∼ 74 K, respectively. In agreement with previous ALMA observations, the models show that the emission region is compact (≲ 5\\buildrel{\\prime\\prime}\\over{.} 5) with gas density n(H2) = (0.7–1)×107 cm‑3. The CH3OH/CH3CN abundance ratio and the evidences for prebiotic and complex organic molecules suggest a rich and active chemistry toward G331.512–0.103.

  5. Rolling Bearing Life Prediction, Theory, and Application

    Science.gov (United States)

    Zaretsky, Erwin V.

    2016-01-01

    A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

  6. Tf2NH-Catalyzed Amide Synthesis from Vinyl Azides and Alcohols.

    Science.gov (United States)

    Zhang, Feng-Lian; Zhu, Xu; Chiba, Shunsuke

    2015-06-19

    Triflimide (Tf2NH) specifically catalyzed reactions of alcohols and vinyl azides, enabling efficient construction of amides with C-C bond formation through nucleophilic attack of vinyl azides onto the putative carbocation intermediates derived from alcohols are described.

  7. GLOBEC NEP Northern California Current Cetacean Survey Data, NH0005, 2000-2000, 0007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) Northern California Current Cetacean Survey Data from R/V New Horizon cruises NH0005 and 0007....

  8. An introduction to NH-A neutron earth base moisture gage

    International Nuclear Information System (INIS)

    Zhu Huaian; Jiang Yulan; Yin Xilin; Yu Peiying; Luo Pinjie

    1988-01-01

    NH-A neutron earth base moisture gage is an accurate instrument which can measure earth moisture rapidly and non-destructively and display moisture results immediately. The deviation is estimated at ±0.012g/cm

  9. Refinement of hydrogen positions in (NH4)2SeO4

    International Nuclear Information System (INIS)

    Loose, A.; Mel'nik, G.; Zink, N.; Wozniak, K.; Dominiak, P.; Smirnov, L.S.; Pawlukojc, A.; Shuvalov, L.A.

    2005-01-01

    The crystal structure of ammonium selenate has been studied by means of single crystal X-ray and neutron diffraction with the purpose of the refinement of hydrogen positions. The refined hydrogen positions obtained by single crystal neutron diffraction show that N-H bond lengths form a regular tetrahedron in an ammonium ion. The single crystal X-ray diffraction data show that N-H bond lengths are shorter than those obtained by neutron diffraction and are not equal between themselves. Thus, the comparison of the results of X-ray and neutron diffraction allows one to suggest that the shorter N-H bond lengths by X-ray diffraction reflect the distribution of the electron charge density of ammonium ions within the (NH 4 ) 2 SeO 4 crystal lattice

  10. Refinement of Hydrogen Positions in (NH$_{4}$)$_{2}$SeO$_{4}$

    CERN Document Server

    Loose, A; Zink, N; Wozniak, K; Dominiak, P; Smirnov, L S; Pawlukojc, A; Shuvalov, L A

    2005-01-01

    The crystal structure of ammonium selenate has been studied by means of single crystal $X$-ray and neutron diffraction with the purpose of the refinement of hydrogen positions. The refined hydrogen positions obtained by single crystal neutron diffraction show that N--H bond lengths form a regular tetrahedron in an ammonium ion. The single crystal $X$-ray diffraction data show that N--H bond lengths are shorter than those obtained by neutron diffraction and are not equal between themselves. Thus, the comparison of the results of $X$-ray and neutron diffraction allows one to suggest that the shorter N-H bond lengths obtained by $X$-ray diffraction reflect the distribution of the electron charge density of ammonium ions within the (NH$_{4})_{2}$SeO$_{4 }$ crystal lattice.

  11. Zn Mediated Regioselective Barbier Reaction of Propargylic Bromides in THF/aq. NH4Cl Solution

    Directory of Open Access Journals (Sweden)

    Uno Mäeorg

    2001-11-01

    Full Text Available The reaction of substituted and unsubstituted propargylic bromides with butanal in presence of zinc power in THF/saturated aqueous NH4Cl solution gave corresponding allenic and propargylic alcohols with high selectivity.

  12. Zn Mediated Regioselective Barbier Reaction of Propargylic Bromides in THF/aq. NH4Cl Solution

    OpenAIRE

    Jõgi, Artur; Mäeorg, Uno

    2001-01-01

    The reaction of substituted and unsubstituted propargylic bromides with butanal in presence of zinc power in THF/saturated aqueous NH4Cl solution gave corresponding allenic and propargylic alcohols with high selectivity.

  13. Use of NH3 fuel to achieve deep greenhouse gas reductions from US transportation

    Directory of Open Access Journals (Sweden)

    Doo Won Kang

    2015-11-01

    The current study demonstrates that NH3-fueled vehicles could be a promising near-term alternative for LDV because of its significant contribution in reducing CO2 emissions compared with vehicles of carbon based fuels.

  14. Hydrogenation of interstellar molecules: a survey for methylenimine (CH2NH)

    Science.gov (United States)

    Dickens, J. E.; Irvine, W. M.; DeVries, C. H.; Ohishi, M.

    1997-01-01

    Methylenimine (CH2NH) has been convincingly detected for the first time outside the Galactic center as part of a study of the hydrogenation of interstellar molecules. We have observed transitions from energy levels up to about 100 K above the ground state in the giant molecular clouds W51, Orion KL and G34.3 + 0.15. In addition, CH2NH was found at the " radical-ion peak" on the quiescent ridge of material in the Orion molecular cloud. The abundance ratio CH2NH/HCN at the radical-ion peak agrees with the predictions of recent gas-phase chemical models. This ratio is an order of magnitude higher in the warmer cloud cores, suggesting additional production pathways for CH2NH, probably on interstellar grains.

  15. NOAA Climate Data Record (CDR) of Northern Hemisphere (NH) Snow Cover Extent (SCE), Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) is a record for the Northern Hemisphere (NH) Snow Cover Extent (SCE) spanning from October 4, 1966 to present, updated monthly...

  16. TOVS GLA 5 DAY GRIDS from NOAA-11 V01 (TOVSA5NH) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset (TOVSA5NH) contains the TIROS Operational Vertical Sounder (TOVS) level 3 geophysical parameters derived using data from NOAA-11 and the physical...

  17. GLOBEC NEP Northern California Current Bird Data NH0005, 2000-2000, 0007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) Northern California Current Bird Data from R/V New Horizon cruises NH0005 and 0007. As a part of...

  18. Seabrook, N.H. Wastewater Treatment Plant Chief Operator Recognized for Outstanding Service

    Science.gov (United States)

    Dustin Price, a resident of Berwick Maine and the Chief Operator of the Seabrook, N.H. Wastewater Treatment Plant, was honored by EPA with a 2016 Regional Wastewater Treatment Plant Operator of the Year Excellence Award.

  19. Crystal structure and characterization of the novel NH{sup +} Midline-Horizontal-Ellipsis N hydrogen bonded polar crystal [NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Wojtas, M., E-mail: maciej.wojtas@chem.uni.wroc.pl [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Gagor, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Science, PO Box 1410, 50-950 Wroclaw (Poland); Czupinski, O. [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Medycki, W. [Institute of Molecular Physics, Polish Academy of Science, Smoluchowskiego 17, 60-179 Poznan (Poland); Jakubas, R. [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland)

    2012-03-15

    Dielectric properties and phase transitions of the piperazinium tetrafluoroborate ([NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}], abbreviated as PFB) crystal are related to the one-dimensional arrangement of the cations linked by the bistable NH{sup +} Midline-Horizontal-Ellipsis N hydrogen bonds and molecular motions of the [BF{sub 4}]{sup -} units. The crystal structure of [NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}] is monoclinic at room temperature with the polar space group Pn. The polar/acentric properties of the room temperature phase IV have been confirmed by the piezoelectric and pyroelectric measurements. DSC measurements show that the compound undergoes three first-order structural phase transitions: at 421/411 K (heating/cooling), at 386/372 K and at 364/349 K. {sup 1}H and {sup 19}F NMR measurements indicate the reorientational motions of [BF{sub 4}]{sup -} anions and piperazinium(+) cations as well as the proton motion in the hydrogen-bonded chains of piperazine along the [001] direction. Over the phase I the isotropic reorientational motions or even self-diffusion of the cations and anions are expected. The conductivity measurements in the vicinity of the II-I PT indicate a superionic phase over the phase I. - Graphical abstract: It must be emphasized that the titled compound represents the first organic-inorganic simple salt containing the single-protonated piperazinium cation which was studied by means of the wide variety of experimental techniques. A survey of Cambridge Structural Database (CSD version 5.32 (November 2010) and updates (May 2011)) for structure containing the piperazinium cations yields 248 compounds with the doubly protonated piperazinium(2+) cations and only eight compounds with the singly protonated piperazinium(+) cations. Among these structures only one is the hybrid organic-inorganic material. This is piperazinium nitrate characterized structurally. The crystal packing of [NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}], phase IV. The

  20. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    Directory of Open Access Journals (Sweden)

    Peter W. Tse

    2017-02-01

    Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  1. Ammonia-solvated ammonium species in the NH(4)-ZSM-5 zeolite.

    Science.gov (United States)

    Bonelli, Barbara; Armandi, Marco; Areán, Carlos O; Garrone, Edoardo

    2010-10-25

    Interaction of gaseous ammonia with a NH(4)-ZSM-5 zeolite (Si/Al=11.5) was studied by means of infrared (IR) spectroscopy both at constant ambient temperature and in the temperature range 373-573 K. H-bonding of NH(3) molecules to the NH(4) (+) species takes place. The interaction is weak and reversible, resembling a solvation process. Spectral evidence shows that only one N--H moiety is actually available, indicating that ammonium ions are tricoordinated to the zeolite inner surface. H-bonded NH(3) has an absorption band at 1712 cm(-1), which grows with increasing pressure in two steps: a monosolvated ammonium species is initially formed, evolving to a disolvated species for pressures above 5 mbar. Coordination of the second NH(3) molecule takes place at the already coordinated NH(3) molecule and not at the ammonium cation. From the changes in intensity of the 1712 cm(-1) band with changing temperature under a moderate NH(3) equilibrium pressure, the calculated standard enthalpy and entropy of the monosolvation reaction were ΔH(0)=-34(±5) kJ mol(-1) and ΔS(0)=-88(±10) J mol(-1) K(-1), respectively. The enthalpy of the second solvation step was calculated from the corresponding equilibrium constant under the assumption of (nearly) the same entropy change for both solvation processes. In agreement with the overall picture, this enthalpy change is small (-15 kJ mol(-1) at the most). Since in a previous work (M. Armandi, B. Bonelli, I. Bottero, C. O. Areán, E. Garrone, J. Phys. Chem. C 2010, 114, 6658) the thermodynamic features of the reaction between bare Brønsted acid sites and NH(3) yielding NH(4) (+) species were determined, the data reported herein allow the study of the coexistence of different species in the NH(3)/H-ZSM-5 zeolite system: 1) unreacted acid Brønsted sites, 2) bare ammonium ions, and 3) variously solvated ammonium species. The relevant description is particularly simple when the overall average coverage is one molecule per site.

  2. Why a German "Oh" Is Not Necessarily an English "Oh": Showing Understanding and Emotions with Change-of-State Tokens

    Science.gov (United States)

    Linneweber, Judith

    2016-01-01

    This paper presents a two-session teaching unit on German change-of-state tokens such as "oh," "ach" and "achso." Goal is to teach students the appropriate reaction through change-of-state tokens in various situations. Students are provided with authentic data based on empirical research in conversation analysis (CA).…

  3. Urban NH3 levels and sources in six major Spanish cities.

    Science.gov (United States)

    Reche, Cristina; Viana, Mar; Karanasiou, Angeliki; Cusack, Michael; Alastuey, Andrés; Artiñano, Begoña; Revuelta, M Aranzazu; López-Mahía, Purificación; Blanco-Heras, Gustavo; Rodríguez, Sergio; Sánchez de la Campa, Ana M; Fernández-Camacho, Rocío; González-Castanedo, Yolanda; Mantilla, Enrique; Tang, Y Sim; Querol, Xavier

    2015-01-01

    A detailed spatial and temporal assessment of urban NH3 levels and potential emission sources was made with passive samplers in six major Spanish cities (Barcelona, Madrid, A Coruña, Huelva, Santa Cruz de Tenerife and Valencia). Measurements were conducted during two different periods (winter-autumn and spring-summer) in each city. Barcelona showed the clearest spatial pattern, with the highest concentrations in the old city centre, an area characterised by a high population density and a dense urban architecture. The variability in NH3 concentrations did not follow a common seasonal pattern across the different cities. The relationship of urban NH3 with SO2 and NOX allowed concluding on the causes responsible for the variations in NH3 levels between measurement periods observed in Barcelona, Huelva and Madrid. However, the factors governing the variations in A Coruña, Valencia and Santa Cruz de Tenerife are still not fully understood. This study identified a broad variability in NH3 concentrations at the city-scale, and it confirms that NH3 sources in Spanish urban environments are vehicular traffic, biological sources (e.g. garbage containers), wastewater treatment plants, solid waste treatment plants and industry. The importance of NH3 monitoring in urban environments relies on its role as a precursor of secondary inorganic species and therefore PMX. Further research should be addressed in order to establish criteria to develop and implement mitigation strategies for cities, and to include urban NH3 sources in the emission inventories. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. A study of proton polarization in ammonia (NH sub 3 ) under irradiation and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, A.A.; Get' man, V.A.; Dzyubak, A.P.; Karnaukhov, I.M.; Lukhanin, A.A.; Neffa, A.Yu.; Semisalov, I.L.; Sorokin, P.V.; Sporov, E.S.; Telegin, Yu.N.; Tolmachev, I.A.; Trotsenko, V.I. (Kharkov Institute of Physics and Technology, Ukrainian SSR, Academy of Sciences, 310108 Kharkov, USSR (UA))

    1989-05-05

    The proton polarization in irradiated NH{sub 3} has been measured as a function of the irradiation dose and annealing temperature. The analysis of the experimental data obtained shows that under low-temperature'' irradiation along with the NH{sup {minus}}{sub 2} the e{sub tr}-radical is likely to be formed which contributes to the polarization build-up and relaxation and influences the radiation damage resistance of the target.

  5. Computer Program of SIE ASME-NH (Revision 1.0) Code

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Gyeong Hoi; Lee, J. H

    2008-01-15

    In this report, the SIE ASME (Structural Integrity Evaluations by ASME-NH) (Revision 1.0), which has a computerized implementation of ASME Pressure Vessels and Piping Code Section III Subsection NH rules, is developed to apply to the next generation reactor design subjecting to the elevated temperature operations over 500 .deg. C and over 30 years design lifetime, and the user's manual for this program is described in detail.

  6. Surface study of platinum decorated graphene towards adsorption of NH3 and CH4

    International Nuclear Information System (INIS)

    Rad, Ali Shokuhi; Pazoki, Hossein; Mohseni, Soheil; Zareyee, Daryoush; Peyravi, Majid

    2016-01-01

    To distinguish the potential of graphene sensors, there is a need to recognize the interaction between graphene sheet and adsorbing molecules. We used density functional theory (DFT) calculations to study the properties of pristine as well as Pt-decorated graphene sheet upon adsorption of NH 3 and CH 4 on its surface to exploit its potential to be as gas sensors for them. We found much higher adsorption, higher charge transfer, lower intermolecular distance, and higher orbital hybridizing upon adsorption of NH 3 and CH 4 gas molecules on Pt-decorated graphene compared to pristine graphene. Also our calculations reveal that the adsorption energies on Pt-decorated graphene sheet are in order of NH 3 >CH 4 which could be corresponded to the order of their sensitivity on this modified surface. We used orbital analysis including density of states as well as frontier molecular orbital study for all analyte-surface systems to more understanding the kind of interaction (physisorption or chemisorption). Consequently, the Pt-decorated graphene can transform the existence of NH 3 and CH 4 molecules into electrical signal and it may be potentially used as an ideal sensor for detection of NH 3 and CH 4 in ambient situation. - Highlights: • Pt-decorated graphene was investigated as an adsorbent for NH 3 and CH 4 . • Much higher adsorption of NH 3 and CH 4 on Pt-decorated graphene than pristine graphene. • Higher adsorption of NH 3 compared to CH 4 on Pt-decorated graphene. • Pt influences the electronic structure of graphene.

  7. Membrane potential independent transport of NH3in the absence of ammonium permeases in Saccharomyces cerevisiae.

    Science.gov (United States)

    Cueto-Rojas, Hugo F; Milne, Nicholas; van Helmond, Ward; Pieterse, Mervin M; van Maris, Antonius J A; Daran, Jean-Marc; Wahl, S Aljoscha

    2017-04-17

    Microbial production of nitrogen containing compounds requires a high uptake flux and assimilation of the N-source (commonly ammonium), which is generally coupled with ATP consumption and negatively influences the product yield. In the industrial workhorse Saccharomyces cerevisiae, ammonium (NH 4 + ) uptake is facilitated by ammonium permeases (Mep1, Mep2 and Mep3), which transport the NH 4 + ion, resulting in ATP expenditure to maintain the intracellular charge balance and pH by proton export using the plasma membrane-bound H + -ATPase. To decrease the ATP costs for nitrogen assimilation, the Mep genes were removed, resulting in a strain unable to uptake the NH 4 + ion. Subsequent analysis revealed that growth of this ∆mep strain was dependent on the extracellular NH 3 concentrations. Metabolomic analysis revealed a significantly higher intracellular NH X concentration (3.3-fold) in the ∆mep strain than in the reference strain. Further proteomic analysis revealed significant up-regulation of vacuolar proteases and genes involved in various stress responses. Our results suggest that the uncharged species, NH 3 , is able to diffuse into the cell. The measured intracellular/extracellular NH X ratios under aerobic nitrogen-limiting conditions were consistent with this hypothesis when NH x compartmentalization was considered. On the other hand, proteomic analysis indicated a more pronounced N-starvation stress response in the ∆mep strain than in the reference strain, which suggests that the lower biomass yield of the ∆mep strain was related to higher turnover rates of biomass components.

  8. Computer Program of SIE ASME-NH (Revision 1.0) Code

    International Nuclear Information System (INIS)

    Koo, Gyeong Hoi; Lee, J. H.

    2008-01-01

    In this report, the SIE ASME (Structural Integrity Evaluations by ASME-NH) (Revision 1.0), which has a computerized implementation of ASME Pressure Vessels and Piping Code Section III Subsection NH rules, is developed to apply to the next generation reactor design subjecting to the elevated temperature operations over 500 .deg. C and over 30 years design lifetime, and the user's manual for this program is described in detail

  9. Oxidation characteristics of chars generated from wood impregnated with (NH4)2HPO4 and (NH4)2SO4

    International Nuclear Information System (INIS)

    Branca, Carmen; Di Blasi, Colomba

    2007-01-01

    Thermogravimetric analysis (heating rates between 5 and 15 K/min up to 873 K) has been carried out in air of chars, generated from the pyrolysis of wood and wood impregnated with (NH 4 ) 2 HPO 4 and (NH 4 ) 2 SO 4 (5%, dry wood basis) which are widely used as flame retardants. Salts significantly alter the char reactivity, but a mechanism consisting of three parallel reactions always provides a good description of the measurements. The estimated activation energy and reaction order of the most important combustion reaction, which causes the release of about 71-80% of the volatile matter, are nearly the same for untreated and (NH 4 ) 2 SO 4 impregnated samples (about 190-200 kJ/mol and 0.86). A lower activation energy (about 150 kJ/mol) and a higher reaction order (1.35) are obtained for (NH 4 ) 2 HPO 4 treatments. Scanning electronic microscope (SEM) images show significant modifications in the morphological structure of both wood and char as a consequence of salt impregnation

  10. Nanoscale structural characterization of Mg(NH3)6Cl2 during NH3 desorption

    DEFF Research Database (Denmark)

    Jacobsen, Hjalte Sylvest; Hansen, Heine Anton; Andreasen, Jens Wenzel

    2007-01-01

    Complex metal hydrides progressively display improved hydrogen storage capacity, but they are still far from fulfilling the requirements of the transport sector. Recently, indirect storage of hydrogen as ammonia in Mg(NH3)(6)Cl-2 has shown impressive capacity and reversibility. Here, we present...

  11. Reactions of H+(pyridinem(H2On and H+(NH31(pyridinem(H2On with NH3: experiments and kinetic modelling

    Directory of Open Access Journals (Sweden)

    E. Uggerud

    2012-03-01

    Full Text Available Reactions between pyridine containing water cluster ions, H+(pyridine1(H2On, H+(pyridine2(H2On and H+(NH31(pyridine1(H2On (n up to 15 with NH3 have been studied experimentally using a quadrupole time-of-flight mass spectrometer. The product ions in the reaction between H+(pyridinem(H2On (m = 1 to 2 and NH3 have been determined for the first time. It is found that the reaction mainly leads to cluster ions of the form H+(NH31(pyridinem(H2On-x, with x = 1 or 2 depending on the initial size of the reacting cluster ion. For a given number of water molecules (from 5 to 15 in the cluster ion, rate coefficients are found to be slightly lower than those for protonated pure water clusters reacting with ammonia. The rate coefficients obtained from this study are used in a kinetic cluster ion model under tropospheric conditions. The disagreement between ambient ground level measurements and previous models are discussed in relation to the results from our model and future experimental directions are suggested.

  12. Shaft Center Orbit in Dynamically Loaded Bearings

    DEFF Research Database (Denmark)

    Klit, Peder

    2005-01-01

    The aim of this work is to demonstrate how to utilize the bearings damping coe±cients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 [1]and described further in 1972 [2]. Several authors have re¯ned this metho...

  13. INVESTIGATION OF SHALLOW FOUNDATION SOIL BEARING ...

    African Journals Online (AJOL)

    This study investigated the soil bearing capacity and foundation settlement characteristics of Minna City Centre development site using standard penetration test (SPT) data obtained from10 SPT boreholes at 0.6, 2.1 and 3.6 m depths to correlate soil properties. Evaluation of foundation bearing capacity and settlement ...

  14. INVESTIGATION OF ANGULAR BALL BEARING WEAR

    Directory of Open Access Journals (Sweden)

    A. L. Savchenko

    2006-01-01

    Full Text Available Wearing process of balls in an angular ball bearing has been investigated in the paper. Force affecting a separator from the side of balls is determined theoretically. Wear rate may be calculated with a formula for abrasive wear while substituting numerical parameter values of the investigated ball bearing for formula symbols.

  15. On the dynamics of ball bearings

    NARCIS (Netherlands)

    Wensing, J.A.

    1998-01-01

    This investigation on the dynamic behaviour of ball bearings was motivated by the demand for silent bearings in noise-sensitive applications, especially in the household appliance and automotive industry. The present investigations are intended to provide a clear understanding of the role of the

  16. Hydrodynamic Lubrication Analysis Of Slider Bearings Lubricated ...

    African Journals Online (AJOL)

    Hydrodynamic Lubrication Analysis Of Slider Bearings Lubricated With Micropolar Fluids. ... In this paper, a theoretical study of the effect of micropolar lubricants on the performance characteristics of wide inclined slider bearings is presented. The finite element method and Gauss Seidel iterative procedure have been used ...

  17. 33 CFR 117.543 - Bear Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bear Creek. 117.543 Section 117.543 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.543 Bear Creek. (a) The draws of the Baltimore...

  18. Friction coefficients of PTFE bearing liner

    Science.gov (United States)

    Daniels, C. M.

    1979-01-01

    Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.

  19. BEARING ANALYSIS FOR THE SPUR TURBOGENERATOR.

    Science.gov (United States)

    The results of the analysis of journal bearing configuration for the SPUR turbogenerator are presented in this report. For this analysis, a computer...laminar analysis agreed with existing solutions, thereby providing a check of the computer program. Several journal bearing mounting arrangements were considered, and a design was selected for initial testing. (Author)

  20. Protecting a Ball-Bearing-Deflection Monitor

    Science.gov (United States)

    Kuhr, George A.

    1987-01-01

    Deflectometer probe monitors deflection of ball-bearing race in liquid oxygen with aid of small window or diaphragm. Diaphragm or window isolates optical deflectometer from liquid oxygen or other fluid in ball bearing. At high pressures, diaphragm integral part of housing preferable to window, since there would be no leakage.

  1. Rotor Vibration Reduction via Active Hybrid Bearings

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

  2. Can polar bear hairs absorb environmental energy?

    OpenAIRE

    He Ji-Huan; Wang Qing-Li; Sun Jie

    2011-01-01

    A polar bear (Ursus maritimus) has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  3. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  4. TEMPERATURE DIAGNOSTICS OF GAS TURBINE ENGINE BEARINGS

    Directory of Open Access Journals (Sweden)

    R. V. Birukov

    2014-01-01

    Full Text Available The objective of the current research was to develop methodology for diagnosing industrial gas turbine engine bearings using the standard performance parameters. This paper presents mathematical thermal model of combined thrust and radial bearing and provides the model application examples for diagnostics.

  5. Charge transfer in the electron donor-acceptor complex BH3NH3.

    Science.gov (United States)

    Mo, Yirong; Song, Lingchun; Wu, Wei; Zhang, Qianer

    2004-03-31

    As a simple yet strongly binding electron donor-acceptor (EDA) complex, BH(3)NH(3) serves as a good example to study the electron pair donor-acceptor complexes. We employed both the ab initio valence bond (VB) and block-localized wave function (BLW) methods to explore the electron transfer from NH(3) to BH(3). Conventionally, EDA complexes have been described by two diabatic states: one neutral state and one ionic charge-transferred state. Ab initio VB self-consistent field (VBSCF) computations generate the energy profiles of the two diabatic states together with the adiabatic (ground) state. Our calculations evidently demonstrated that the electron transfer between NH(3) and BH(3) falls in the abnormal regime where the reorganization energy is less than the exoergicity of the reaction. The nature of the NH(3)-BH(3) interaction is probed by an energy decomposition scheme based on the BLW method. We found that the variation of the charge-transfer energy with the donor-acceptor distance is insensitive to the computation levels and basis sets, but the estimation of the amount of electron transferred heavily depends on the population analysis procedures. The recent resurgence of interest in the nature of the rotation barrier in ethane prompted us to analyze the conformational change of BH(3)NH(3), which is an isoelectronic system with ethane. We found that the preference of the staggered structure over the eclipsed structure of BH(3)NH(3) is dominated by the Pauli exchange repulsion.

  6. Application procedures and analysis examples of the SIE ASME-NH program

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seok Hoon; Koo, G. H.; Kim, J. B. [KAERI, Daejeon (Korea, Republic of)

    2010-12-15

    In this report, the design rule of the ASME-NH Code was briefly summarized and the application procedures of SIE ASME-NH program were analysed, the analysis examples were described. The SIE ASME-NH program was developed according to the ASME Code Section III Subsection NH rules to perform the primary stress limits, the accumulated inelastic strain limits and the creep fatigue damage evaluations in the structural design of nuclear power plants operating with high temperatures over creep temperature at normal operating conditions. In the analysis examples, the benchmark problem for the high temperature reactor vessel which was discussed in the SIE ASME-NH user's seminar was described. Also, the preliminary structural analysis of an Advanced Burner Test Reactor internal structure was described. Considering the load combinations of the various cycle types submitted from significant operating conditions, the integrity of a reactor internal structure was reviewed according to the stress and strain limits of the ASME-NH rules and the analysis and evaluation results were summarized

  7. Application procedures and analysis examples of the SIE ASME-NH program

    International Nuclear Information System (INIS)

    Kim, Seok Hoon; Koo, G. H.; Kim, J. B.

    2010-12-01

    In this report, the design rule of the ASME-NH Code was briefly summarized and the application procedures of SIE ASME-NH program were analysed, the analysis examples were described. The SIE ASME-NH program was developed according to the ASME Code Section III Subsection NH rules to perform the primary stress limits, the accumulated inelastic strain limits and the creep fatigue damage evaluations in the structural design of nuclear power plants operating with high temperatures over creep temperature at normal operating conditions. In the analysis examples, the benchmark problem for the high temperature reactor vessel which was discussed in the SIE ASME-NH user's seminar was described. Also, the preliminary structural analysis of an Advanced Burner Test Reactor internal structure was described. Considering the load combinations of the various cycle types submitted from significant operating conditions, the integrity of a reactor internal structure was reviewed according to the stress and strain limits of the ASME-NH rules and the analysis and evaluation results were summarized

  8. [Effects of superphosphate addition on NH3 and greenhouse gas emissions during vegetable waste composting].

    Science.gov (United States)

    Yang, Yan; Sun, Qin-ping; Li, Ni; Liu, Chun-sheng; Li, Ji-jin; Liu, Ben-sheng; Zou, Guo-yuan

    2015-01-01

    To study the effects of superphosphate (SP) on the NH, and greenhouse gas emissions, vegetable waste composting was performed for 27 days using 6 different treatments. In addition to the controls, five vegetable waste mixtures (0.77 m3 each) were treated with different amounts of the SP additive, namely, 5%, 10%, 15%, 20% and 25%. The ammonia volatilization loss and greenhouse gas emissions were measured during composting. Results indicated that the SP additive significantly decreased the ammonia volatilization and greenhouse gas emissions during vegetable waste composting. The additive reduced the total NH3 emission by 4.0% to 16.7%. The total greenhouse gas emissions (CO2-eq) of all treatments with SP additives were decreased by 10.2% to 20.8%, as compared with the controls. The NH3 emission during vegetable waste composting had the highest contribution to the greenhouse effect caused by the four different gases. The amount of NH3 (CO2-eq) from each treatment ranged from 59.90 kg . t-1 to 81.58 kg . t-1; NH3(CO2-eq) accounted for 69% to 77% of the total emissions from the four gases. Therefore, SP is a cost-effective phosphorus-based fertilizer that can be used as an additive during vegetable waste composting to reduce the NH3 and greenhouse gas emissions as well as to improve the value of compost as a fertilizer.

  9. Optical monitoring of CH3NH3PbI3 thin films upon atmospheric exposure

    International Nuclear Information System (INIS)

    Ghimire, Kiran; Zhao, Dewei; Cimaroli, Alex; Ke, Weijun; Yan, Yanfa; Podraza, Nikolas J

    2016-01-01

    CH 3 NH 3 PbI 3 perovskite films of interest for photovoltaic (PV) devices have been prepared by (i) vapor deposition and (ii) solution processing. Complex dielectric function ( ε   =   ε 1   +  i ε 2 ) spectra and structural parameters of the films have been extracted using near infrared to ultraviolet spectroscopic ellipsometry. In situ real time spectroscopic ellipsometry (RTSE) over a 48 h period has been performed on vapor deposited CH 3 NH 3 PbI 3 after the deposition in normal atmospheric laboratory ambient conditions. Analysis of RTSE data for vapor deposited CH 3 NH 3 PbI 3 film prepared under un-optimized conditions identifies phase segregated PbI 2 and CH 3 NH 3 I at the substrate/film interface and unreacted PbI 2 and CH 3 NH 3 I on the film surface. This analysis also provides the time dependence of the effective thicknesses of perovskite film, unreacted components, and phase segregated layers to track CH 3 NH 3 PbI 3 decomposition. (paper)

  10. [Influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton].

    Science.gov (United States)

    Dong, Hairong; Li, Jincai; Li, Cundong

    2004-04-01

    The influence of different NH4+/NO3- ratios on nitrogen metabolism of cotton was studied under controlled hydroponics. The results showed that compared with single nitrate nutrition, solutions with 25/75, 50/50, 75/25 and 100/0 of NH4+/NO3- significantly increased the soluble protein accumulation in leaves and roots of cotton, and the maximum content of soluble protein in leaves and roots appeared respectively in the solution with 50/50 and 75/25 of NH4+/NO3-. The soluble protein content in roots was increased with the increase of NH4+ percentage, but was slightly less in the solution of 100/0 than 75/25, which was probably related to the excess NH4+ limiting boot metabolism. With the increase of NH4+ percentage, the nitrate content in petiole and the nitrate reductase activity in functional blade declined, but ammoniac nitrogen content increased in every organ of cotton. These results showed that foreign nitrogen affected the nitrogen metabolism of cotton in a different way, and the nitrogen absorption by cotton was probably related to different forms of foreign nitrogen.

  11. Photostriction of CH3NH3PbBr3 Perovskite Crystals

    KAUST Repository

    Wei, Tzu-Chiao

    2017-07-17

    Organic-inorganic hybrid perovskite materials exhibit a variety of physical properties. Pronounced coupling between phonon, organic cations, and the inorganic framework suggest that these materials exhibit strong light-matter interactions. The photoinduced strain of CH3 NH3 PbBr3 is investigated using high-resolution and contactless in situ Raman spectroscopy. Under illumination, the material exhibits large blue shifts in its Raman spectra that indicate significant structural deformations (i.e., photostriction). From these shifts, the photostrictive coefficient of CH3 NH3 PbBr3 is calculated as 2.08 × 10-8 m2 W-1 at room temperature under visible light illumination. The significant photostriction of CH3 NH3 PbBr3 is attributed to a combination of the photovoltaic effect and translational symmetry loss of the molecular configuration via strong translation-rotation coupling. Unlike CH3 NH3 PbI3 , it is noted that the photostriction of CH3 NH3 PbBr3 is extremely stable, demonstrating no signs of optical decay for at least 30 d. These results suggest the potential of CH3 NH3 PbBr3 for applications in next-generation optical micro-electromechanical devices.

  12. A new ab initio potential energy surface for the NH-He complex

    Science.gov (United States)

    Ramachandran, R.; Kłos, J.; Lique, F.

    2018-02-01

    We present a new three-dimensional potential energy surface (PES) for the NH(X3Σ-)-He van der Waals system, which explicitly takes into account the NH vibrational motion. The NH-He PES was obtained using the open-shell single- and double-excitation coupled cluster approach with non-iterative perturbational treatment of triple excitations. The augmented correlation-consistent aug-cc-pVXZ (X = Q, 5, 6) basis sets were employed, and the energies obtained were then extrapolated to the complete basis set limit. Using this new PES, we have studied the spectroscopy of the NH-He complex and we have determined a new rotational constant that agrees well with the available experimental data. Collisional excitation of NH(X3Σ-) by He was also studied at the close-coupling level. Calculations of the collisional excitation cross sections of the fine-structure levels of NH by He were performed for energies up to 3500 cm-1, which yield, after thermal average, rate coefficients up to 350 K. The calculated rate coefficients are compared with available experimental measurements at room temperature, and a reasonably good agreement is found between experimental and theoretical data.

  13. Effect of LiOH, NaOH and KOH on corrosion and oxide microstructure of Zr-based alloys

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, H.G.; Jung, Y.H.; Ruhmann, H.

    1999-01-01

    Long-term corrosion test, SIMS analysis, and TEM microstructural study were carried out to investigate the corrosion characteristics and mechanism of Zr alloys in alkali hydroxides. The corrosion tests were performed in solutions of LiOH, NaOH, KOH, RbOH, and CsOH at 350 deg. C for 500 days. SIMS analysis was performed for the specimens prepared to have an equal oxide thickness. TEM studies on the specimens with an equal oxide thickness in various solutions in both pre- and post-transition regimes were also conducted. The corrosion rate in alkali hydroxide solutions was observed to decrease as the ionic radius of alkali cation was increased. The penetration depth of cation into the oxide decreases with increasing the ionic radius of cation. Even though the oxide thickness was equal, the different oxide morphologies were observed in specimens. Namely, in LiOH solution the oxide morphology was transformed early from columnar to equiaxed structure. However, in KOH solution the columnar structure was maintained up to post-transition regime. Based on the corrosion test, SIMS analysis, and microstructural study, the cation is considered to control the corrosion in a alkali hydroxide solution and its effect is dependent on the concentration of alkali and the oxide thickness. The slight acceleration of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide while the significant acceleration at a high concentration is due to the transformation of oxide microstructure that would be induced by cation incorporation. KOH was shown not to affect significantly the corrosion and the hydrogen pickup of Zircaloy. Therefore, it has a potential for PWR application only from the point of view of Zircaloy corrosion. (author)

  14. In Vitro and In Vivo Evaluation of Alexa Fluor 680-Bombesin[7–14]NH2 Peptide Conjugate, a High-Affinity Fluorescent Probe with High Selectivity for the Gastrin-Releasing Peptide Receptor

    Directory of Open Access Journals (Sweden)

    Lixin Ma

    2007-05-01

    Full Text Available Gastrin-releasing peptide (GRP receptors are overexpressed on several types of human cancer cells, including breast, prostate, small cell lung, and pancreatic cancers. Bombesin (BBN, a 14–amino acid peptide that is an analogue of human GRP, binds to GRP receptors with very high affinity and specificity. The aim of this study was to develop a new fluorescent probe based on BBN having high tumor uptake and optimal pharmacokinetics for specific targeting and optical imaging of human breast cancer tissue. In this study, solid-phase peptide synthesis was used to produce H2N-glycylglycylglycine-BBN[7–14]NH2 peptide with the following general sequence: H2N-G-G-G-Q-W-A-V-G-H-L-M-(NH2. This conjugate was purified by reversed-phase high-performance liquid chromatography and characterized by electrospray-ionization mass spectra. The fluorescent probe Alexa Fluor 680-G-G-G-BBN[7–14]NH2 conjugate was prepared by reaction of Alexa Fluor 680 succinimidyl ester to H2N-G-G-G-BBN[7–14]NH2 in dimethylformamide (DMF. In vitro competitive binding assays, using 125I-Tyr4-BBN as the radiolabeling gold standard, demonstrated an inhibitory concentration 50% value of 7.7 ± 1.4 nM in human T-47D breast cancer cells. Confocal fluorescence microscopy images of Alexa Fluor 680-G-G-G-BBN[7–14]NH2 in human T-47D breast cancer cells indicated specific uptake, internalization, and receptor blocking of the fluorescent bioprobe in vitro. In vivo investigations in SCID mice bearing xenografted T-47D breast cancer lesions demonstrated the ability of this new conjugate to specifically target tumor tissue with high selectivity and affinity.

  15. In vitro and in vivo evaluation of Alexa Fluor 680-bombesin[7-14]NH2 peptide conjugate, a high-affinity fluorescent probe with high selectivity for the gastrin-releasing peptide receptor.

    Science.gov (United States)

    Ma, Lixin; Yu, Ping; Veerendra, Bhadrasetty; Rold, Tammy L; Retzloff, Lauren; Prasanphanich, Adam; Sieckman, Gary; Hoffman, Timothy J; Volkert, Wynn A; Smith, Charles J

    2007-01-01

    Gastrin-releasing peptide (GRP) receptors are overexpressed on several types of human cancer cells, including breast, prostate, small cell lung, and pancreatic cancers. Bombesin (BBN), a 14-amino acid peptide that is an analogue of human GRP, binds to GRP receptors with very high affinity and specificity. The aim of this study was to develop a new fluorescent probe based on BBN having high tumor uptake and optimal pharmacokinetics for specific targeting and optical imaging of human breast cancer tissue. In this study, solid-phase peptide synthesis was used to produce H(2)N-glycylglycylglycine-BBN[7-14]NH(2) peptide with the following general sequence: H(2)N-G-G-G-Q-W-A-V-G-H-L-M-(NH(2)). This conjugate was purified by reversed-phase high-performance liquid chromatography and characterized by electrospray-ionization mass spectra. The fluorescent probe Alexa Fluor 680-G-G-G-BBN[7-14]NH(2) conjugate was prepared by reaction of Alexa Fluor 680 succinimidyl ester to H(2)N-G-G-G-BBN[7-14]NH(2) in dimethylformamide (DMF). In vitro competitive binding assays, using (125)I-Tyr(4)-BBN as the radiolabeling gold standard, demonstrated an inhibitory concentration 50% value of 7.7 +/- 1.4 nM in human T-47D breast cancer cells. Confocal fluorescence microscopy images of Alexa Fluor 680-G-G-G-BBN[7-14]NH(2) in human T-47D breast cancer cells indicated specific uptake, internalization, and receptor blocking of the fluorescent bioprobe in vitro. In vivo investigations in SCID mice bearing xenografted T-47D breast cancer lesions demonstrated the ability of this new conjugate to specifically target tumor tissue with high selectivity and affinity.

  16. Kinetics of selected elementary reactions of NH(a{sup 1}{delta}) or ND(a{sup {delta}}), NH(X{sup 3}{sigma}{sup -}) or ND(X{sup 3}{sigma}{sup -}) and NH{sub 2}(X), NHD(X), NH{sub 2}(X) radicals; Untersuchung der Kinetik ausgewaehlter Elementarreaktionen von NH(a{sup 1}{delta})- bzw. ND(a{sup 1}{delta})-, NH(X{sup 3}{sigma}{sup -})- bzw. ND(X{sup 3}{sigma}{sup -})- und NH{sub 2}(X)-, NHD(X)-, ND{sub 2}(X)-Radikalen

    Energy Technology Data Exchange (ETDEWEB)

    Adam, L.

    2002-02-01

    The elementary reactions of the NH and ND radicals in the ground state and the first excited state with H({sup 2}S) atoms and with molecules containing hydrogen and fluorine element bonds were investigated in the gaseous phase at a pressure of p = 7-80 bar. The elementary reactions of the NH{sub 2}, NHD and ND{sub 2} radicals in the ground state with hydrogen halides in the gaseous phase were investigated as well. [German] Die Elementarreaktionen des NH- bzw. ND-Radikals im Elektronengrundzustand und im ersten elektronisch angeregten Zustand mit H({sup 2}S)-Atomen und mit Molekuelen, die Wasserstoff- und Fluor-Elementbindungen besitzen, wurden in der Gasphase bei einem Druck von p = 7 - 80 mbar untersucht. Weiterhin wurden die Elementarreaktionen der NH{sub 2}-, NHD- bzw. ND{sub 2}-Radikale im Elektronengrundzustand mit Halogenwasserstoffen in der Gasphase untersucht. (orig.)

  17. Effect of mixing geopolymer and peat on bearing capacity in Ogan Komering Ilir (OKI) by California bearing ratio (CBR) test

    Science.gov (United States)

    Raharja, Danang S.; Hadiwardoyo, Sigit P.; Rahayu, Wiwik; Zain, Nasuhi

    2017-06-01

    Geopolymer is binder material that consists of solid material and the activator solution. Geopolymer material has successfully replaced cement in the manufacture of concrete with aluminosilicate bonding system. Geopolymer concrete has properties similar to cement concrete with high compressive strength, low shrinkage value, relatively low creep value, as well as acid-resistant. Based on these, the addition of polymers in peat soils is expected to improve the bearing capacity of peat soils. A study on the influence of geopolymer addition in peat soils was done by comparing before and after the peat soil was mixed with geopolymer using CBR (California Bearing Ratio) test in unsoaked and soaked conditions. 10% mixture content of the peat dry was used, weighted with a variety of curing time 4 hours, 5 days, and 10 days. There were two methods of mixing: first, peat was mixed with fly ash geopolymer activators and mixed solution (waterglass, NaOH, water), and second, peat was mixed with fly ash and mixed geopolymer (waterglass, NaOH, water, fly ash). Changes were observed in specific gravity, dry density, acidity (pH), and the microscopic structure with Scanning Electron Microscope (SEM). Curing time did not significantly affect the CBR value. It even shows a tendency to decline with longer curing time. The first type mixture obtained CBR value of: 5.4% for 4 hours curing, 4.6% for 5 days curing and 3.6% for 10 days curing. The second type mixture obtained CBR value of: 6.1% for 4 hours curing, 5.2% for 5 days curing and 5.2% for 10 days curing. Furthermore, the specific gravity value, dry density, pH near neutral and swelling percentage increased. From both variants, the second type mixture shows better results than the first type mixture. The results of SEM (Scanning Electron Microscopy) show the structure of the peat which became denser with the fly ash particles filling the peat microporous. Also, the reaction of fly ash with geopolymer is indicated by the solid

  18. Gas Lubricated Foil Bearing Development for Advanced Turbomachines

    Science.gov (United States)

    1977-03-01

    Rear Journal Bearing Runner 29 3.1.6 Forward Journal Bearing Runner Stress and DefJection Analysis 32 3.1.7 Critical Speed Analysis 35 3.1.8 Thermal...Analysis 39 3.1.8.1 Journal Bearing Temperatures 42 3.1.8.2 Thrust Bearing Temperatures 50 3.2 Design 56 3.2.1 Baseline Bearing Design 56 3.2.1.1 Journal ... Bearing Baseline Design 57 3.2.1.2 Thrust Bearing Baseline Design 59 3.2.2 Thrust Bearing Test Rig Design 61 3.2.3 Journal Bearing Test Rig Design 63

  19. Transient response of two lobe aerodynamic journal bearing

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Yadav

    2018-03-01

    Full Text Available The dynamic behavior of a rotor-dynamic system is greatly affected by the performance of aerodynamic bearing and the performance of bearing is characterized by the stiffness and damping coefficients. In the present work, stiffness and damping coefficients of bearing are computed and the performance of the bearing is greatly changed with the change in bearing air film profile. The effect of lobe offset factors on the transient performance of aerodynamic bearing is presented. Bifurcation and Poincare diagrams of two lobe journal bearing have been presented for different offset factors. A bearing designer can judge the bearing performance based on bifurcation diagrams.

  20. OH, HO2 and RO2 Radical and OH Reactivity Observations during the Summertime in Beijing: High In-Situ Ozone Production and Evidence of a Missing OH Source.

    Science.gov (United States)

    Whalley, L.; Ye, C.; Slater, E.; Woodward-Massey, R.; Lee, J. D.; Squires, F. A.; Hopkins, J. R.; Dunmore, R.; Shaw, M.; Hamilton, J.; Lewis, A. C.; Crilley, L.; Kramer, L. J.; Bloss, W.; Heard, D. E.

    2017-12-01

    Despite substantial reductions in primary emissions of pollutants in China over the past decade, concentrations of the secondary pollutant, ozone, still frequently exceed air quality threshold limits in urban areas during the summertime. We will present measurements of OH, HO2 and RO2 radicals and OH reactivity made in central Beijing at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, close to the North 4th ring road in May and June 2017 which formed the summer phase of `An Integrated Study of AIR Pollution PROcesses'. Elevated levels of O3 (>100 ppbv) were regularly observed. NO concentrations were elevated during the morning but often decreased to below the instrument limit of detection during the afternoon hours when the ozone concentrations peaked. Biogenic emissions influenced the chemistry at the site, with several ppbv of isoprene measured during the afternoons. The OH measurements were made using the FAGE technique, equipped with an inlet pre injector (IPI) which provides an alternative method to determine the instrument background signal by injecting a scavenger to remove ambient OH and ensures an artefact-free OH measurement. Elevated levels of OH were observed, with a mean peak OH concentration of 1.2×107 molecule cm-3 at noon; but with OH concentrations reaching up to 2.5×107 molecule cm-3 on some days. Mean peak HO2 concentrations of 3×108 molecule cm-3 and total RO2 of 1.2×109 molecule cm-3 were recorded, with maximum concentrations of 1.0×109 molecule cm-3 and 4×109 molecule cm-3 observed for HO2 and RO2 respectively, suggesting significant in situ ozone production. A comparison of the artefact-free OH observations with steady state calculations, constrained to the total OH reactivity measurement and known OH precursors that were measured alongside OH, highlights a significant missing daytime OH source under low [NO], with the steady state OH concentrations approximately a factor of two lower than the OH concentrations

  1. The dynamic state monitoring of bearings system

    Directory of Open Access Journals (Sweden)

    Marek Krynke

    2015-03-01

    Full Text Available The article discusses the methods of dynamic state monitoring of bearings system. A vibration signal contains important technical information about the machine condition and is currently the most frequently used in diagnostic bearings systems. One of the main ad-vantages of machine condition monitoring is identifying the cause of failure of the bearings and taking preventative measures, otherwise the operation of such a machine will lead to frequent replacement of the bearings. Monitoring changes in the course of the operation of machin-ery repair strategies allows keeping the conditioned state of dynamic failure conditioned preventive repairs and repairs after-failure time. In addition, the paper also presents the fundamental causes of bearing failure and identifies mechanisms related to the creation of any type of damage.

  2. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing...... the rotational speed ranges by improving damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing startup torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable bearings can act as "smart......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  3. Development of gadolinia bearing fuel for PWR

    International Nuclear Information System (INIS)

    Seki, Kazuichiro

    1986-01-01

    In the PWR power plants in Japan, the long-period operation cycle was extended legally to a maximum of 13 months from the conventional about 9 months in fiscal 1980. With this move, as a new type of fuel with burnable-poison-rod function, the development was started of gadolinia-bearing (gadolinium oxide) fuel, gadolinia being contained in the fuel pellets. The basic technology studies were completed in fiscal 1984. Actual irradiation of the fuel in Unit 2 of the Oi Power Station was then started in July 1984, demonstrating validity of the design. Meanwhile, the rapid power-up fest and the fuel center temperature measurement are conducted in an overseas reactor from fiscal 1983. The following are described: functions of the burnable absorber, the need for gadolinia-bearing fuel, experiences with gadolinia-bearing fuel, problems in the design and production of gadolinia-bearing fuel, the development of gadolinia-bearing fuel. (Mori, K.)

  4. Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

    Science.gov (United States)

    Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

    2009-01-01

    Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

  5. Wave journal bearing with compressible lubricant--Part 1: The wave bearing concept and a comparison to the plain circular bearing

    Science.gov (United States)

    Dimofte, Florin

    1995-01-01

    To improve hydrodynamic journal bearing steady-state and dynamic performance, a new bearing concept, the wave journal bearing, was developed at the author's lab. This concept features a waved inner bearing diameter. Compared to other alternative bearing geometries used to improve bearing performance such as spiral or herring-bone grooves, steps, etc., the wave bearing's design is relatively simple and allows the shaft to rotate in either direction. A three-wave bearing operating with a compressible lubricant, i.e., gas is analyzed using a numerical code. Its performance is compared to a plain (truly) circular bearing over a broad range of bearing working parameters, e.g., bearing numbers from 0.01 to 100.

  6. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and bearing...

  7. 24 CFR 3285.202 - Soil classifications and bearing capacity.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Soil classifications and bearing... Soil classifications and bearing capacity. The soil classification and bearing capacity of the soil... bearing capacity must be determined by one or more of the following methods, unless the soil bearing...

  8. Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 1: Journal bearing performance

    Science.gov (United States)

    Ruscitto, D.; Mccormick, J.; Gray, S.

    1978-01-01

    A 38.1 mm (1.5 inch) diameter Hydresil Compliant Surface Air Lubricated Journal Bearing was designed and tested to obtain bearing performance characteristics at both room temperature and 315 C (600 F). Testing was performed at various speeds up to 60,000 rpm with varying loads. Rotating sensors provided an opportunity to examine the film characteristics of the compliant surface bearing. In addition to providing minimum film thickness values and profiles, many other insights into bearing operation were gained such as the influence of bearing fabrication accuracy and the influence of smooth foil deflection between the bumps.

  9. Failure of GIMBAL bearing in directional GYRO

    International Nuclear Information System (INIS)

    Pervaiz, R.; Baig, N.A.; Shahid, M.; Ahmad, A.; Chohan, G.Y.

    2003-01-01

    This paper relates to the directional gyro of a sensing device used in indigenously developed surface-to-surface missile. The assembling of more than one thousand components in the form of several sub assemblies including hundreds of silver solders of this device was done in the hundred-thousands-class clean room according to assembly procedure. Whereas more than twenty bearings including gimbals bearings were assembled in the ten-thousands-class clean room after inspection/ testing them on beating testing system as per routine. The device was entered in testing and adjustment phase after successful completion of assembly work. The directional gyro qualified all the tests except the most critical one, the drift-rate. The drift-rate of outer gimbal was 60% more than permissible limit whereas drift-rate of inner gimbal was found O.K. It was diagnosed that at least one inner gimbal bearing out of two had some problem. The results were same after rebalancing of gimbals three times. The directional gyro was disassembled in clean room and the radial-thrust-bearing was recovered and flange bearing which are inner gimbal bearings. They were checked on bearing testing system and it was found that flange-bearing had more friction than permissible limit and hence rejected but radial thrust bearing were declared O.K. The gyro was reassembled with new O.K. flange bearing and the assembly work was completed in all respects. The sensing device qualified all the tests including the drift-rate. This case study is being presented to emphasize the importance of careful assembly of gyro in clean environment. (author)

  10. Parathyroid hormone may maintain bone formation in hibernating black bears (Ursus americanus) to prevent disuse osteoporosis.

    Science.gov (United States)

    Donahue, Seth W; Galley, Sarah A; Vaughan, Michael R; Patterson-Buckendahl, Patricia; Demers, Laurence M; Vance, Josef L; McGee, Meghan E

    2006-05-01

    Mechanical unloading of bone causes an imbalance in bone formation and resorption leading to bone loss and increased fracture risk. Black bears (Ursus americanus) are inactive for up to six months during hibernation, yet bone mineral content and strength do not decrease with disuse or aging. To test whether hibernating bears have biological mechanisms to prevent disuse osteoporosis, we measured the serum concentrations of hormones and growth factors involved in bone metabolism and correlated them with the serum concentration of a bone formation marker (osteocalcin). Serum was obtained from black bears over a 7-month duration that included periods of activity and inactivity. Both resorption and formation markers increased during hibernation, suggesting high bone turnover occurred during inactivity. However, bone formation appeared to be balanced with bone resorption. The serum concentration of parathyroid hormone (PTH) was higher in the hibernation (P=0.35) and post-hibernation (P=0.006) seasons relative to pre-hibernation levels. Serum leptin was lower (Phibernation relative to pre-hibernation and hibernation periods. Insulin-like growth factor I (IGF-I) decreased (Phibernation relative to pre-hibernation and reached its highest value during remobilization. There was no difference (P=0.64) in 25-OH vitamin D between the three seasons. Serum osteocalcin (bone formation marker) was significantly correlated with PTH, but not with leptin, IGF-I or 25-OH vitamin D. Osteocalcin and PTH were positively correlated when samples from all seasons were pooled and when only hibernation samples were considered, raising the possibility that the anabolic actions of PTH help maintain bone formation to prevent disuse osteoporosis. Prostaglandin E(2) (PGE(2)) release from MC3T3 osteoblastic cells was significantly affected by treatment with bear serum from different seasons (i.e. hibernation versus active periods). The seasonal changes in PGE(2) release showed trends similar to the

  11. Genomic evidence of widespread admixture from polar bears into brown bears during the last ice age.

    Science.gov (United States)

    Cahill, James A; Heintzman, Peter D; Harris, Kelley; Teasdale, Matthew D; Kapp, Joshua; Soares, André E Rodrigues; Stirling, Ian; Bradley, Daniel; Edwards, Ceiridwen J; Graim, Kiley; Kisleika, Aliaksandr A; Malev, Alexander V; Monaghan, Nigel; Green, Richard E; Shapiro, Beth

    2018-02-20

    Recent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic introgression. However, because it has mainly been possible to sample bears from the present day, the timing, frequency, and evolutionary significance of this admixture remains unknown. Here, we analyze genomic DNA from three additional and geographically distinct brown bear populations, including two that lived temporally close to the peak of the last ice age. We find evidence of admixture in all three populations, suggesting that admixture between these species has been common in their recent evolutionary history. In addition, analyses of ten fossil bears from the now-extinct Irish population indicate that admixture peaked during the last ice age, when brown bear and polar bear ranges overlapped. Following this peak, the proportion of polar bear ancestry in Irish brown bears declined rapidly until their extinction. Our results support a model in which ice age climate change created geographically widespread conditions conducive to admixture between polar bears and brown bears, as is again occurring today. We postulate that this model will be informative for many admixing species pairs impacted by climate change. Our results highlight the power of paleogenomics to reveal patterns of evolutionary change that are otherwise masked in contemporary data.

  12. Bear-ly” learning: Limits of abstraction in black bear cognition

    Directory of Open Access Journals (Sweden)

    Jennifer Vonk

    2018-02-01

    Full Text Available We presented two American black bears (Ursus americanus with a serial list learning memory task, and one of the bears with a matching-to-sample task. After extended training, both bears demonstrated some success with the memory task but failed to generalize the overarching rule of the task to novel stimuli. Matching to sample proved even more difficult for our bear to learn. We conclude that, despite previous success in training bears to respond to natural categories, quantity discriminations, and other related tasks, that bears may possess a cognitive limitation with regards to learning abstract rules. Future tests using different procedures are necessary to determine whether this is a limit of bears’ cognitive capacities, or a limitation of the current tasks as presented. Future tests should present a larger number of varying stimuli. Ideally, bears of various species should be tested on these tasks to demonstrate species as well as individual differences.

  13. Vibration quenching in a large scale rotor-bearing system using journal bearings with variable geometry

    Science.gov (United States)

    Chasalevris, Athanasios; Dohnal, Fadi

    2014-03-01

    In large scale rotating machinery the resonance amplitude during the passage through resonance is a matter of consideration because of its influence in the surrounding environment of the rotational system and foundation. In this paper, a variable geometry journal bearing (VGJB), recently patented, is applied for the mounting of a large scale rotor bearing system operating at the range of medium speed. The simulation of the rotor-bearing system incorporates a recent method for simulation of a multi-segment continuous rotor in combination with nonlinear bearing forces. The use of the current bearing gives results that encourage the use of such a bearing in rotating machinery since the vibration amplitude during the passage through the critical speed can be reduced up to 60-70%. In the presented study, the developed amplitude and the rotor stresses are severely reduced compared to those of the system with normal cylindrical journal bearings during a virtual start up of the system.

  14. Process-based modelling of NH3 exchange with grazed grasslands

    Science.gov (United States)

    Móring, Andrea; Vieno, Massimo; Doherty, Ruth M.; Milford, Celia; Nemitz, Eiko; Twigg, Marsailidh M.; Horváth, László; Sutton, Mark A.

    2017-09-01

    In this study the GAG model, a process-based ammonia (NH3) emission model for urine patches, was extended and applied for the field scale. The new model (GAG_field) was tested over two modelling periods, for which micrometeorological NH3 flux data were available. Acknowledging uncertainties in the measurements, the model was able to simulate the main features of the observed fluxes. The temporal evolution of the simulated NH3 exchange flux was found to be dominated by NH3 emission from the urine patches, offset by simultaneous NH3 deposition to areas of the field not affected by urine. The simulations show how NH3 fluxes over a grazed field in a given day can be affected by urine patches deposited several days earlier, linked to the interaction of volatilization processes with soil pH dynamics. Sensitivity analysis showed that GAG_field was more sensitive to soil buffering capacity (β), field capacity (θfc) and permanent wilting point (θpwp) than the patch-scale model. The reason for these different sensitivities is dual. Firstly, the difference originates from the different scales. Secondly, the difference can be explained by the different initial soil pH and physical properties, which determine the maximum volume of urine that can be stored in the NH3 source layer. It was found that in the case of urine patches with a higher initial soil pH and higher initial soil water content, the sensitivity of NH3 exchange to β was stronger. Also, in the case of a higher initial soil water content, NH3 exchange was more sensitive to the changes in θfc and θpwp. The sensitivity analysis showed that the nitrogen content of urine (cN) is associated with high uncertainty in the simulated fluxes. However, model experiments based on cN values randomized from an estimated statistical distribution indicated that this uncertainty is considerably smaller in practice. Finally, GAG_field was tested with a constant soil pH of 7.5. The variation of NH3 fluxes simulated in this way

  15. Products of reaction of OH radicals with α-pinene

    Science.gov (United States)

    Aschmann, Sara M.; Atkinson, Roger; Arey, Janet

    2002-07-01

    Products of the gas-phase reaction of α-pinene with OH radicals in the presence of NO have been investigated using gas chromatography with flame ionization detection to quantify pinonaldehyde and in situ atmospheric pressure ionization mass spectrometry in the negative ion mode to quantify selected other products as their NO2- adducts by utilizing C6-dihydroxycarbonyls and C6-hydroxynitrates formed in situ from the reaction of OH radicals with 1-hexene as an internal standard. The products quantified, and their molar formation yields, were: pinonaldehyde, 28 +/- 5% molecular weight 184 product (dihydroxycarbonyl), 19% (with an estimated uncertainty of a factor of ~2) molecular weight 200 product, 11% (with an estimated uncertainty of a factor of ~2). Together with a very approximate yield from our API-MS analyses for the formation of organic nitrates (~1%) and literature data for acetone (plus coproducts), ~65-70% of the reaction products and pathways are accounted for.

  16. Clumped isotope effects during OH and Cl oxidation of methane

    DEFF Research Database (Denmark)

    Whitehill, Andrew R.; Joelsson, Lars Magnus T.; Schmidt, Johan Albrecht

    2017-01-01

    A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH...... was produced from the reaction of O(1D) (from O3 photolysis) with H2O, and Cl was from photolysis of Cl2. Samples were taken from the reaction cell and analyzed for methane (12CH4, 12CH3D, 13CH4, 13CH3D) isotopologue ratios using tunable infrared laser direct absorption spectroscopy. Measured kinetic isotope...... effects for singly substituted species were consistent with previous experimental studies. For doubly substituted methane, 13CH3D, the observed kinetic isotope effects closely follow the product of the kinetic isotope effects for the 13C and deuterium substituted species (i.e., 13,2KIE = 13KIE × 2KIE...

  17. Dither-free stabilization of CH3OH pumping sources

    Science.gov (United States)

    Bennett, C. A.; Patterson, J. D.; Hutchinson, D. P.

    1986-08-01

    A dither-free stabilization scheme was reported recently1 in which the optical transmission through an absorption cell filled with CH2F2 provided an error signal necessary to stabilize the 214-μm line of CH2F2. Measurements have indicated that this technique is difficult to apply to the 119-μm line of CH3OH due to a lack of contrast in the absorption features of CH3OH over the tuning range of the pump. Efforts to find a nonlasant gas with the required absorption features and to develop a similar technique based on the photoacoustic technique will be described. This research was supported by the Office of Fusion Energy, U.S. DOE, under Contract No. DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc.

  18. Equatorial enhancement of the nighttime OH mesospheric infrared airglow

    International Nuclear Information System (INIS)

    Baker, D J; Thurgood, B K; Harrison, W K; Mlynczak, M G; Russell, J M

    2007-01-01

    Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (Δv=2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H+O 3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings

  19. Inversion mechanisms for OH main lines astrophysical masers

    International Nuclear Information System (INIS)

    Elitzur, M.

    1977-01-01

    Excitation processes that can lead to inversion of the main lines of the OH ground state are discussed. Due to the frequency dependence of the emission coefficient of dust, far-IR emitted by warm enough dust can excite the upper halves of the Λ-doublets of rotational levels more strongly than the lower halves. The cascade back to the ground state will then invert the main lines and it is shown that this mechanism can explain rather well the main lines emission from OH-IR stars. The main lines masers associated with compact HII regions are discussed extensively. It is argued that the most plausible explanation for them is a model based on the mechanism suggested some time ago by Johnston where the inversion is due to collisional excitation by streams of uni-directional electrons. (author)

  20. From employee representation to problem-solving: Mainstreaming OHS management

    DEFF Research Database (Denmark)

    Hasle, Peter; Seim, Rikke; Refslund, Bjarke

    2016-01-01

    The role of occupational health and safety representatives is changing. A study in 60 Danish enterprises indicates that representation, and especially negotiation on behalf of colleagues, has diminished. The work environment is mainstreamed in many enterprises and is rarely an area of conflict....... The role of OHS representatives has accordingly changed to focus on solving specific problems in the workplace as an integrated part of daily operations. Both management and colleagues consider the OHS representatives as a resource that can be utilized to manage the work environment. The consequences...... of this development for the employees may be a stronger joint management–employee effort to improve the work environment, but also management domination and an accordingly weaker employee voice in some companies....